BOK Financial (BOKF) 10-K 28 Feb 17 2016 FY Annual report Financial data

Document And Entity Information

Document And Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2016	Jan. 31, 2017	Jun. 30, 2016
Document and Entity Information [Abstract]
Entity Registrant Name	BOK FINANCIAL CORP ET AL
Entity Central Index Key	875,357
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Public Float			$ 1,588,744,146
Entity Common Stock, Shares Outstanding		65,489,810
Document Fiscal Year Focus	2,016
Document Fiscal Period Focus	FY
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2016

Consolidated Statements of Earn

Consolidated Statements of Earnings - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Interest and dividend revenue [Abstract]
Loans	$ 581,030	$ 529,683	$ 502,753
Residential mortgage loans held for sale	12,658	13,602	10,143
Trading securities	8,527	2,240	1,945
Investment securities	16,894	18,098	18,891
Available for sale securities	175,321	174,829	185,107
Fair value option securities	6,723	9,264	3,611
Restricted equity securities	17,238	13,532	7,040
Interest-bearing cash and cash equivalents	10,726	5,580	2,749
Total interest and dividend revenue	829,117	766,828	732,239
Interest expense [Abstract]
Deposits	40,494	44,170	50,683
Borrowed funds	35,336	14,204	7,672
Subordinated debentures	6,059	5,100	8,690
Total interest expense	81,889	63,474	67,045
Net interest and dividend revenue	747,228	703,354	665,194
Provision for credit losses	65,000	34,000	0
Net interest and dividend revenue after provision for credit losses	682,228	669,354	665,194
Other operating revenue [Abstract]
Brokerage and trading revenue	138,377	129,556	134,437
Transaction card revenue	135,758	128,621	123,689
Fiduciary and asset management revenue	135,477	126,153	115,652
Deposit service charges and fees	92,193	90,431	90,911
Mortgage banking revenue	133,914	126,002	109,093
Other revenue	51,029	49,883	47,537
Total fees and commissions	686,748	650,646	621,319
Other gains, net	4,030	5,702	2,953
Gain (loss) on derivatives, net	(15,685)	430	2,776
Gain (loss) on fair value option securities, net	(10,555)	(3,684)	10,189
Change in fair value of mortgage servicing rights	(2,193)	(4,853)	(16,445)
Gain on available for sale securities, net	11,675	12,058	1,539
Total other-than-temporary impairment losses	0	(2,443)	(373)
Portion of loss recognized in other comprehensive income	0	624	0
Net impairment losses recognized in earnings	0	(1,819)	(373)
Total other operating revenue	674,020	658,480	621,958
Other operating expense [Abstract]
Personnel	553,119	515,298	476,931
Business promotion	26,582	27,851	26,649
Charitable contributions to BOKF Foundation	2,000	796	4,267
Professional fees and services	56,783	40,123	44,440
Net occupancy and equipment	80,024	76,016	77,232
Insurance	32,489	20,375	18,578
Data processing and communications	131,841	122,383	115,225
Printing, postage and supplies	15,584	13,498	13,518
Net losses and operating expenses of repossessed assets	3,359	1,446	6,019
Amortization of intangible assets	6,862	4,359	3,965
Mortgage banking costs	61,387	38,813	31,705
Other expense	47,560	35,233	28,993
Total other operating expense	1,017,590	896,191	847,522
Net income before taxes	338,658	431,643	439,630
Federal and state income taxes	106,377	139,384	144,151
Net income	232,281	292,259	295,479
Net income (loss) attributable to non-controlling interests	(387)	3,694	3,044
Net income attributable to BOK Financial Corporation shareholders	$ 232,668	$ 288,565	$ 292,435
Earnings per share: [Abstract]
Basic (in dollars per share)	$ 3.53	$ 4.22	$ 4.23
Diluted (in dollars per share)	$ 3.53	$ 4.21	$ 4.22
Average shares used in computation: [Abstract]
Basic (in shares)	65,085,627	67,594,689	68,394,194
Diluted (in shares)	65,143,898	67,691,658	68,544,770
Dividends declared per share (in dollars per share)	$ 1.73	$ 1.69	$ 1.62

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Statement of Comprehensive Income [Abstract]
Net income		$ 232,281	$ 292,259	$ 295,479
Other comprehensive income (loss), before income taxes: [Abstract]
Net change in unrealized gain (loss)		(41,521)	(46,803)	136,775
Reclassification adjustments included in earnings: [Abstract]
Interest revenue, Investment securities, Taxable securities		(112)	(503)	(1,216)
Interest expense, Subordinated debentures		0	121	296
Net impairment losses recognized in earnings		0	1,819	373
Gain on available for sale securities, net		(11,675)	(12,058)	(1,539)
Other comprehensive income (loss), before income taxes		(53,308)	(57,424)	134,689
Federal and state income taxes	[1]	(20,754)	(22,338)	52,393
Other comprehensive income (loss), net of income taxes		(32,554)	(35,086)	82,296
Comprehensive income		199,727	257,173	377,775
Comprehensive income (loss) attributable to non-controlling interests		(387)	3,694	3,044
Comprehensive income attributable to BOK Financial Corp. shareholders		$ 200,114	$ 253,479	$ 374,731
[1]	Calculated using 39% effective tax rate.

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Assets [Abstract]
Cash and due from banks	$ 620,846	$ 573,699
Interest-bearing cash and cash equivalents	1,916,651	2,069,900
Trading securities	337,628	122,404
Investment securities	546,145	597,836
Available for sale securities	8,676,829	9,042,733
Fair value option securities	77,046	444,217
Restricted equity securities	307,240	273,684
Residential mortgage loans held for sale	301,897	308,439
Loans	16,989,660	15,941,154
Allowance for loan losses	(246,159)	(225,524)
Loans, net of allowance	16,743,501	15,715,630
Premises and equipment, net	325,849	306,490
Receivables	772,952	163,480
Goodwill	448,899	385,461
Intangible assets, net	46,931	43,909
Mortgage servicing rights	247,073	218,605
Real estate and other repossessed assets, net of allowance	44,287	30,731
Derivative contracts	689,872	586,270
Cash surrender value of bank-owned life insurance	308,430	303,335
Receivable on unsettled available for sale securities sales	7,188	40,193
Other assets	353,017	249,112
Total assets	32,772,281	31,476,128
Deposits [Abstract]
Noninterest-bearing demand deposits	9,235,720	8,296,888
Interest-bearing Deposit Liabilities [Abstract]
Transaction	10,865,105	9,998,954
Savings	425,470	386,252
Time	2,221,800	2,406,064
Total deposits	22,748,095	21,088,158
Funds purchased	57,929	491,192
Repurchase agreements	668,661	722,444
Other borrowings	4,846,072	4,837,879
Subordinated debentures	144,640	226,350
Accrued interest, taxes and expense	146,704	119,584
Derivative contracts	664,531	581,701
Due on unsettled available for sale securities purchases	6,508	16,897
Other liabilities	182,784	124,284
Total liabilities	29,465,924	28,208,489
Shareholders' equity: [Abstract]
Common stock	4	4
Capital surplus	1,006,535	982,009
Retained earnings	2,823,334	2,704,121
Treasury stock	(544,052)	(477,165)
Accumulated other comprehensive income (loss)	(10,967)	21,587
Total shareholders’ equity	3,274,854	3,230,556
Non-controlling interests	31,503	37,083
Total equity	3,306,357	3,267,639
Total liabilities and equity	$ 32,772,281	$ 31,476,128

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Investment securities [Abstract]
Investment securities, fair value	$ 565,493	$ 629,159
Real estate and other repossessed assets, allowance	$ 9,562	$ 12,622
Shareholders' equity: [Abstract]
Common stock, par value (in dollars per share)	$ 0.00006	$ 0.00006
Common stock, authorized (in shares)	2,500,000,000	2,500,000,000
Common stock, shares issued (in shares)	74,993,407	74,530,364
Common stock, shares outstanding (in shares)	74,993,407	74,530,364
Treasury stock, shares at cost (in shares)	9,655,975	8,636,332

Consolidated Statements of Chan

Consolidated Statements of Changes in Equity - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock [Member]	Capital Surplus [Member]	Retained Earnings [Member]	Treasury Stock [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Total Shareholders' Equity [Member]	Non-Controlling Interests [Member]
Balance, beginning of period (in shares) at Dec. 31, 2013		73,163			4,305
Balance, beginning of period at Dec. 31, 2013	$ 3,054,973	$ 4	$ 898,586	$ 2,349,428	$ (202,346)	$ (25,623)	$ 3,020,049	$ 34,924
Net income	295,479			292,435			292,435	3,044
Other comprehensive income (loss)	82,296					82,296	82,296
Repurchase of common stock (in shares)					200
Repurchase of common stock	(12,337)				$ (12,337)		(12,337)
Issuance of shares for equity compensation, net (in shares)		510			183
Issuance of shares for equity compensation, net	4,472		16,632		$ (12,160)		4,472
Tax effect from equity compensation, net	8,258		8,258				8,258
Share-based compensation	9,680		9,680				9,680
Issuance of shares in settlement of deferred compensation, net (in shares)		331			202
Issuance of shares in settlement of deferred compensation, net	8,352		21,488		$ (13,136)		8,352
Cash dividends on common stock	(111,026)			(111,026)			(111,026)
Capital calls and distributions, net	(3,941)							(3,941)
Balance, end of period (in shares) at Dec. 31, 2014		74,004			4,890
Balance, end of period at Dec. 31, 2014	3,336,206	$ 4	954,644	2,530,837	$ (239,979)	56,673	3,302,179	34,027
Net income	292,259			288,565			288,565	3,694
Other comprehensive income (loss)	(35,086)					(35,086)	(35,086)
Repurchase of common stock (in shares)					3,634
Repurchase of common stock	(229,540)				$ (229,540)		(229,540)
Issuance of shares for equity compensation, net (in shares)		526			112
Issuance of shares for equity compensation, net	6,711		14,357		$ (7,646)		6,711
Tax effect from equity compensation, net	925		925				925
Share-based compensation	12,083		12,083				12,083
Cash dividends on common stock	(115,281)			(115,281)			(115,281)
Sale of non-controlling interest	5,500							5,500
Capital calls and distributions, net	(6,138)							(6,138)
Balance, end of period (in shares) at Dec. 31, 2015		74,530			8,636
Balance, end of period at Dec. 31, 2015	3,267,639	$ 4	982,009	2,704,121	$ (477,165)	21,587	3,230,556	37,083
Net income	232,281			232,668			232,668	(387)
Other comprehensive income (loss)	(32,554)					(32,554)	(32,554)
Repurchase of common stock (in shares)					1,005
Repurchase of common stock	(66,792)				$ (66,792)		(66,792)
Issuance of shares for equity compensation, net (in shares)		463			15
Issuance of shares for equity compensation, net	12,370		12,465		$ (95)		12,370
Tax effect from equity compensation, net	1,590		1,590				1,590
Share-based compensation	10,471		10,471				10,471
Cash dividends on common stock	(113,455)			(113,455)			(113,455)
Capital calls and distributions, net	(5,193)							(5,193)
Balance, end of period (in shares) at Dec. 31, 2016		74,993			9,656
Balance, end of period at Dec. 31, 2016	$ 3,306,357	$ 4	$ 1,006,535	$ 2,823,334	$ (544,052)	$ (10,967)	$ 3,274,854	$ 31,503

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Cash Flows From Operating Activities: [Abstract]
Net income	$ 232,281	$ 292,259	$ 295,479
Adjustments to reconcile net income to net cash provided by (used in) operating activities: [Abstract]
Provision for credit losses	65,000	34,000	0
Change in fair value of mortgage servicing rights due to market changes	2,193	4,853	16,445
Change in fair value of mortgage servicing rights due to loan runoff	40,744	28,064	19,325
Unrealized losses (gains) from derivative contracts	11,234	964	(6,495)
Depreciation and amortization	47,016	37,918	36,707
Tax effect from equity compensation, net	(1,505)	(925)	(8,258)
Share-based compensation	10,471	12,083	9,680
Net amortization of securities discounts and premiums	41,643	55,145	57,202
Net realized gains on financial instruments and other assets	(13,011)	(15,212)	(1,362)
Net gain on mortgage loans held for sale	(63,636)	(75,780)	(62,053)
Mortgage loans originated for sale	(6,117,417)	(6,372,956)	(4,484,394)
Proceeds from sale of mortgage loans held for sale	6,193,587	6,446,659	4,441,819
Capitalized mortgage servicing rights	(71,405)	(79,546)	(54,413)
Change in trading and fair value option securities	149,921	(69,298)	(243,265)
Change in receivables	(603,861)	(6,943)	(7,103)
Change in other assets	(49,565)	(29,548)	68,821
Change in accrued interest, taxes and expense	44,269	17,517	(115,772)
Change in other liabilities	(11,413)	15,756	1,007
Net cash provided by (used in) operating activities	(93,454)	295,010	(36,630)
Cash Flows From Investing Activities: [Abstract]
Proceeds from sales of available for sale securities	899,381	1,600,380	2,664,740
Proceeds from maturities or redemptions of investment securities	86,847	72,664	63,258
Proceeds from maturities or redemptions of available for sale securities	1,740,226	1,542,517	1,635,533
Purchases of investment securities	(41,590)	(25,132)	(44,723)
Purchases of available for sale securities	(2,333,740)	(3,300,601)	(3,045,077)
Change in amount receivable on unsettled securities sales	33,005	34,066	(57,085)
Loans originated, net of principal collected	(621,605)	(1,681,035)	(1,346,995)
Net payments on derivative asset contracts	(103,668)	(156,419)	(247,726)
Proceeds from disposition of assets	198,922	195,760	273,271
Acquisitions, net of cash acquired	56,017	(18,098)	(21,898)
Purchases of assets	(199,802)	(265,406)	(307,318)
Net cash used in investing activities	(286,007)	(2,001,304)	(434,020)
Cash Flows From Financing Activities: [Abstract]
Net change in demand deposits, transaction deposits and savings accounts	1,277,285	149,951	958,809
Net change in time deposits	(216,084)	(202,652)	(87,277)
Net change in other borrowed funds	(606,476)	2,547,688	511,776
Repayment of subordinated debentures	226,550	121,810	0
Issuance of subordinated debentures, net of issuance costs	144,615	0	0
Change in amount due on unsettled security purchases	(10,389)	(273,643)	244,800
Issuance of common and treasury stock, net	12,455	6,711	4,472
Net change in derivative margin accounts	(28,806)	(43,226)	84,365
Net payments or proceeds on derivative liability contracts	106,051	149,428	257,439
Tax effect from equity compensation, net	1,505	925	8,258
Sale of non-controlling interests	0	5,500	0
Repurchase of common stock	(66,792)	(229,540)	(12,337)
Dividends paid	(113,455)	(115,281)	(111,026)
Net cash provided by financing activities	273,359	1,874,051	1,859,279
Net increase (decrease) in cash and cash equivalents	(106,102)	167,757	1,388,629
Cash and cash equivalents at beginning of period	2,643,599	2,475,842	1,087,213
Cash and cash equivalents at end of period	2,537,497	2,643,599	2,475,842
Supplemental Cash Flow Information: [Abstract]
Cash paid for interest	82,876	66,091	65,721
Cash paid for taxes	79,883	101,991	67,199
Net loans and bank premises transferred to repossessed real estate and other assets	36,391	12,592	79,464
Residential mortgage loans guaranteed by U.S. government agencies that became eligible for repurchase during the period	120,406	123,383	144,630
Conveyance of other real estate owned guaranteed by U.S. government agencies	68,873	110,505	44,963
Issuance of shares in settlement of accrued executive compensation	$ 0	$ 0	$ 8,352

Significant Accounting Policies

Significant Accounting Policies	12 Months Ended
	Dec. 31, 2016
Accounting Policies [Abstract]
Significant Accounting Policies [Text Block]	Significant Accounting Policies Basis of Presentation The Consolidated Financial Statements of BOK Financial Corporation (“BOK Financial” or “the Company”) have been prepared in conformity with accounting principles generally accepted in the United States ("U.S. GAAP"), including interpretations of U.S. GAAP issued by federal banking regulators and general practices of the banking industry. The consolidated financial statements include the accounts of BOK Financial and its subsidiaries, principally BOKF, NA, BOK Financial Securities, Inc., The Milestone Group, Inc. and Cavanal Hill Investment Management, Inc. All significant intercompany transactions are eliminated in consolidation. The consolidated financial statements include the assets, liabilities, non-controlling interests and results of operations of variable interest entities (“VIEs”) when BOK Financial is determined to be the primary beneficiary. Variable interest entities are generally defined as entities that either do not have sufficient equity to finance their activities without support from other parties or whose equity investors lack a controlling financial interest. See additional discussion of variable interest entities at Note 14 following. Certain prior year amounts have been reclassified to conform to the current year presentation. For 2015, $8.4 million of residential mortgage loan origination costs were reclassified from operating expense to mortgage banking revenue. Correction of this error did not affect net income or earnings per share. Nature of Operations BOK Financial, through its subsidiaries, provides a wide range of financial services to commercial and industrial customers, other financial institutions, municipalities, and consumers. These services include depository and cash management; lending and lease financing; mortgage banking; securities brokerage, trading and underwriting; and personal and corporate trust. BOKF, NA operates as Bank of Oklahoma primarily in the Tulsa and Oklahoma City metropolitan areas of the state of Oklahoma and Bank of Texas primarily in the Dallas, Fort Worth and Houston metropolitan areas of the state of Texas. In addition, BOKF, NA does business as Bank of Albuquerque in Albuquerque, New Mexico; Colorado State Bank and Trust in Denver, Colorado; Bank of Arizona in Phoenix, Arizona; Bank of Kansas City and Mobank in Kansas City, Missouri/Kansas and Bank of Arkansas in Northwest Arkansas. BOKF, NA also operates the TransFund electronic funds network. Use of Estimates Preparation of BOK Financial's consolidated financial statements requires management to make estimates of future economic activities, including loan collectability, prepayments and cash flows from customer accounts. These estimates are based upon current conditions and information available to management. Actual results may differ significantly from these estimates. Acquisitions Assets and liabilities acquired, including identifiable intangible assets, are recorded at fair value on the acquisition date. The purchase price includes consideration paid at closing and the estimated fair value of contingent consideration that will be paid in the future, subject to achieving defined performance criteria. Premiums and discounts assigned to interest-earning assets and interest-bearing liabilities are amortized over the lives of the acquired assets and liabilities on either an individual instrument or pool basis. Provision for credit losses is recognized for changes in credit quality after the acquisition date. Goodwill is recognized as the excess of the purchase price over the net fair value of assets acquired and liabilities assumed. The Consolidated Statements of Earnings include the results of operations from the acquisition date. Goodwill and Intangible Assets Goodwill and intangible assets generally result from business combinations and are evaluated for each of BOK Financial's reporting units for impairment annually or more frequently if conditions indicate impairment. The evaluation of possible impairment of goodwill and intangible assets involves significant judgment based upon short-term and long-term projections of future performance. Reporting units are defined by the Company as significant lines of business within each operating segment. This definition is consistent with the manner in which the chief operating decision maker assesses the performance of the Company and makes decisions concerning the allocation of resources. The Company qualitatively assesses whether it is more likely than not that the fair value of the reporting units are less than their carrying value, including goodwill. Reporting unit carrying value includes sufficient capital to exceed regulatory requirements. This assessment includes consideration of relevant events and circumstances including but not limited to macroeconomic conditions, industry and market conditions, the financial and stock performance of the Company and other relevant factors. If the Company concludes that it is not more likely than not that the fair value of a reporting unit is less than its carrying value through the qualitative assessment, a quantitative Step 1 analysis is performed. The quantitative analysis compares the fair value of the reporting unit with its carrying value, including goodwill. The fair value of each reporting unit is estimated by the discounted future earnings method. Goodwill is considered impaired if the fair value of the reporting unit is less than the carrying value of the reporting unit, including goodwill. Impairment is measured through a detailed Step 2 assessment of the fair values for each asset and liability assigned to the reporting unit performed in a manner similar to a business combination. Intangible assets are generally composed of customer relationships, naming rights, non-compete agreements and core deposit premiums. They are amortized using accelerated or straight-line methods, as appropriate, over the estimated benefit periods. These periods range from 3 years to 20 years . The net book values of identifiable intangible assets are evaluated for impairment when economic conditions indicate impairment may exist. Cash Equivalents Due from banks, funds sold (generally federal funds sold for one day), resell agreements (which generally mature within one to 30 days ) and investments in money market funds are considered cash equivalents. Securities Securities are identified as trading, investment (held to maturity) or available for sale at the time of purchase based upon the intent of management, liquidity and capital requirements, regulatory limitations and other relevant factors. Trading securities, which are acquired for profit through resale, are carried at fair value with unrealized gains and losses included in current period earnings. Investment securities are carried at amortized cost. Amortization is computed by methods that approximate level yield and is adjusted for changes in prepayment estimates. Securities identified as available for sale are carried at fair value. Unrealized gains and losses are recorded, net of deferred income taxes, as accumulated other comprehensive income in shareholders' equity. Available for sale securities are separately identified as pledged to creditors if the creditor has the right to sell or re-pledge the collateral. The purchase or sale of securities is recognized on a trade date basis. Realized gains and losses on sales of securities are based upon specific identification of the security sold. A receivable or payable is recognized for subsequent transaction settlement. Securities meeting certain criteria may also be transferred from the available for sale classification to the investment securities portfolio at fair value on the date of transfer. The unrealized gain or loss at the date of transfer is retained in accumulated other comprehensive income and in the carrying value of the investment securities portfolio. Such amounts are amortized over the estimated remaining life of the security as an adjustment to yield, offsetting the related amortization of the premium or accretion of the discount on the transferred securities. On a quarterly basis, the Company performs separate evaluations of impaired debt investment and available for sale securities and equity available for sale securities to determine if the decline in fair value below the amortized cost is other-than-temporary. For debt securities, management determines whether it intends to sell or if it is more likely than not that it will be required to sell impaired securities. This determination considers current and forecasted liquidity requirements and securities portfolio management. If the Company intends to sell or it is more likely than not that it will be required to sell the impaired debt security, a charge is recognized against earnings for the entire unrealized loss. For all impaired debt securities for which there is no intent or expected requirement to sell, the evaluation considers all available evidence to assess whether it is more likely than not that all amounts due would not be collected according to the security's contractual terms. Impairment of debt securities rated investment grade by all nationally-recognized rating agencies is considered temporary unless specific contrary information is identified. Impairment of debt securities rated below investment grade by at least one of the nationally recognized rating agencies is evaluated based on projections of estimated cash flows. Any expected credit loss due to the inability to collect all amounts due according to the security's contractual terms is recognized as a charge against earnings. Any remaining unrealized loss related to other factors would be recognized in other comprehensive income, net of taxes. For equity securities, management evaluates various factors including cause, severity and duration of the decline in value of the security and prospects for recovery, as well as the Company's intent and ability not to sell the security until the fair value exceeds amortized cost over periods not to exceed three years. If an unrealized loss is determined to be other-than-temporary, a charge is recognized against earnings for the difference between the security's amortized cost and fair value. BOK Financial may elect to carry certain securities at fair value with changes in fair value recognized in current period income. These securities are held with the intent that gains or losses will offset changes in the fair value of mortgage servicing rights or certain derivative instruments. Restricted equity securities represent equity interests the Company is required to hold in the Federal Reserve Banks and Federal Home Loan Banks. Restricted equity securities are carried at cost as these securities do not have a readily determined fair value because ownership of these shares is restricted and they lack a market. Derivative Instruments Derivative instruments may be used by the Company as part of its internal risk management programs or may be offered to customers. All derivative instruments are carried at fair value and changes in fair value are generally reported in income as they occur. The determination of fair value of derivative instruments considers changes in interest rates, commodity prices and foreign exchange rates. Credit risk is also considered in determining fair value. Deterioration in the credit rating of customers or other counterparties reduces the fair value of asset contracts. Deterioration of our credit rating could decrease the fair value of our derivative liabilities. When bilateral netting agreements or similar agreements exist between the Company and its counterparties that create a single legal claim or obligation to pay or receive the net amount in settlement of the individual derivative contracts, the Company reports derivative assets and liabilities on a net by derivative contract by counterparty basis. Derivative contracts may also require the Company to provide or receive cash margin as collateral for derivative assets and liabilities. Derivative assets and liabilities are reported net of cash margin when certain conditions are met. In addition, derivative contracts executed with customers under Customer Risk Management Programs may be secured by non-cash collateral in conjunction with a credit agreement with that customer. Access to collateral, in the event of default is reasonably assured. Derivative instruments may be designated as cash flow hedges of variable rate assets or liabilities, or of anticipated transactions. Changes in the fair value of derivative instruments designated as cash flow hedges are recorded in accumulated other comprehensive income to the extent they are effective. The amount recorded in other comprehensive income is reclassified to earnings in the same periods as the hedged cash flows impact earnings. The ineffective portion of changes in fair value is reported in current earnings. BOK Financial may use derivative instruments in managing its interest rate sensitivity, as part of its economic hedge of the changes in the fair value of mortgage servicing rights and as an economic hedge of trading securities. Changes in the fair value of derivative instruments used in managing interest rate sensitivity and as part of its economic hedge of changes in the fair value of mortgage servicing rights are included in Other Operating Revenue - Gain (loss) on derivatives, net in the Consolidated Statement of Earnings. Changes in the fair value of derivative instruments used as an economic hedge of trading securities are included in Operating Revenue- Brokerage and trading revenue. BOK Financial also enters into mortgage loan commitments that are considered derivative contracts. Forward sales contracts that have not been designated as hedging instruments are used to economically hedge these mortgage loan commitments as well as mortgage loans held for sale. Mortgage loan commitments are carried at fair value based upon quoted prices. Changes in fair value of mortgage loan commitments, mortgage loans held for sale and forward sales contracts are reported in Other Operating Revenue - Mortgage Banking Revenue. BOK Financial offers programs that permit its customers to manage various risks, including fluctuations in energy, cattle and other agricultural products, interest rates and foreign exchanges rates with derivative contracts. Customers may also manage interest rate risk through interest rate swaps used by the borrower to modify interest rate terms of their loans or to-be-announced securities used by our mortgage banking customers to hedge their loan production. Derivative contracts are executed between the customers and BOK Financial. Offsetting contracts are executed between BOK Financial and other selected counterparties to minimize market risk from changes in commodity prices, interest rates or foreign exchange rates. The counterparty contracts are identical to customer contracts, except for a fixed pricing spread or fee paid to BOK Financial as profit and compensation for administrative costs and credit risk which is recognized over the life of the contracts and included in other Operating Revenue - Brokerage and Trading Revenue in the Consolidated Statements of Earnings. Loans Loans are either secured or unsecured based on the type of loan and the financial condition of the borrower. Repayment is generally expected from cash flow or proceeds from the sale of selected assets of the borrower. BOK Financial is exposed to risk of loss on loans due to the borrower's financial difficulties, which may arise from any number of factors, including problems within the respective industry or local economic conditions. Access to collateral, in the event of borrower default, is reasonably assured through adherence to applicable lending laws and through sound lending standards and credit review procedures. Accounting policies for all loans, excluding residential loans guaranteed by U.S. government agencies, are as follows. Interest is accrued at the applicable interest rate on the outstanding principal amount. Loans are placed on nonaccruing status when, in the opinion of management, full collection of principal or interest is uncertain. Internally risk graded loans are individually evaluated for nonaccruing status quarterly. Non-risk graded loans are generally placed on nonaccruing status when 90 days or more past due or within 60 days of being notified of the borrower's bankruptcy filing. Interest previously accrued but not collected is charged against interest income when the loan is placed on nonaccruing status. Payments received on nonaccruing loans are applied to principal or recognized as interest income, according to management's judgment as to the collectability of principal. Loans may be returned to accruing status when, in the opinion of management, full collection of principal and interest, including principal previously charged off, is probable based on improvements in the borrower's financial condition or a sustained period of performance. Loans to borrowers experiencing financial difficulties may be modified in troubled debt restructurings ("TDRs"). All TDRs are classified as nonaccruing. Modifications generally consist of extension of payment terms or interest rate concessions and may result either voluntarily through negotiations with the borrower or involuntarily through court order. Generally, principal and accrued but unpaid interest is not voluntarily forgiven. Performing loans may be renewed under the current collateral, debt service ratio and other underwriting standards. Nonaccruing loans may also be renewed and will remain classified as nonaccruing. Occasionally, loans, other than residential mortgage loans, may be held for sale in order to manage credit concentration. These loans are carried at the lower of cost or fair value with gains or losses recognized in gain (loss) on assets. All loans are charged-off when the loan balance or a portion of the loan balance is no longer supported by the paying capacity of the borrower or when the required cash flow is reduced in a TDR. The charge-off amount is determined through an evaluation of available cash resources and collateral value. Internally risk graded loans are evaluated quarterly and charge-offs are taken in the quarter in which the loss is identified. Non-risk graded loans that are past due between 60 days and 180 days , based on the loan product type, are charged off. Loans to borrowers whose personal obligation has been discharged through Chapter 7 bankruptcy proceedings are charged off within 60 days of notice of the bankruptcy filing, regardless of payment status. Loan origination and commitment fees and direct loan acquisition and origination costs are deferred and amortized as an adjustment to yield over the life of the loan or over the commitment period, as applicable. Amortization does not anticipate loan prepayments. Net unamortized fees are recognized in full at time of payoff. Qualifying residential mortgage loans guaranteed by U.S. government agencies have been sold into GNMA pools. Under certain performance conditions specified in government programs, the Company has the right, but not the obligation to repurchase loans from GNMA pools. These loans no longer qualify for sale accounting and are recognized in the Consolidated Balance Sheet. Guaranteed loans are considered to be impaired because we do not expect to receive all principal and interest based on the loan's contractual terms. The principal balance continues to be guaranteed, however, interest accrues at a curtailed rate as specified in the programs. The carrying value of these loans is reduced based on an estimate of expected cash flows discounted at the original note rate plus a liquidity spread. Guaranteed loans may be modified in TDRs in accordance with U.S. government agency guidelines. Interest continues to accrue at the modified rate. U.S. government guaranteed loans may either be resold into GNMA pools after a performance period specified by the programs or foreclosed and conveyed to the guarantors. Loans are disaggregated into portfolio segments and further disaggregated into classes. The portfolio segment is the level at which the Company develops and documents a systematic method for determining its Allowance for Credits Losses. Classes are based on the risk characteristics of the loans and the Company's method for monitoring and assessing credit risk. Allowance for Loan Losses and Accrual for Off-Balance Sheet Credit Risk The appropriateness of the allowance for loan losses and accrual for off-balance sheet credit risk (collectively "Allowance for Credit Losses") is assessed by management quarterly based on an ongoing quarterly evaluation of the probable estimated losses inherent in the portfolio, including probable losses on outstanding loans and unused commitments to provide financing. A consistent well-documented methodology has been developed and is applied by an independent Credit Administration department to assure consistency across the Company. The allowance for loan losses consists of specific allowances attributed to impaired loans that have not yet been charged down to amounts we expect to recover, general allowances based on estimated loss rates by loan class and nonspecific allowances based on factors that affect more than one portfolio segment. There were no changes to the methodology for estimating general allowances during 2016 or 2015 . Loans are considered to be impaired when it becomes probable that BOK Financial will be unable to collect all amounts due according to the contractual terms of the loan agreements. Internally risk graded loans are evaluated individually for impairment. Substantially all commercial and commercial real estate loans and certain residential mortgage and personal loans are risk graded based on a quarterly evaluation of the borrowers' ability to repay. Certain commercial loans and most residential mortgage and personal loans are small balance, homogeneous pools of loans that are not risk graded. Non-risk graded loans are identified as impaired based on performance status. Generally, non-risk graded loans 90 days or more past due, modified in a troubled debt restructuring or in bankruptcy are considered to be impaired. Specific allowances for impaired loans are measured by an evaluation of estimated future cash flows discounted at the loan's initial effective interest rate or the fair value of collateral for certain collateral dependent loans. The fair value of real property held as collateral is generally based on third party appraisals that conform to Uniform Standards of Professional Appraisal Practice, less estimated selling costs. Appraised values are on an “as-is” basis and generally are not adjusted by the Company. Updated appraisals are obtained at least annually or more frequently if market conditions indicate collateral values may have declined. Collateral value of mineral rights is generally determined by our internal staff of engineers based on projected cash flows from proven oil and gas reserves under existing economic and operating conditions. The value of other collateral is generally determined by our special assets staff based on projected liquidation cash flows under current market conditions. Collateral values and available cash resources that support impaired loans are evaluated quarterly. Historical statistics may be used as a practical way to estimate impairment in limited situations, such as when a collateral dependent loan is identified as impaired at the end of a reporting period until an appraisal of collateral value is received or a full assessment of future cash flows is completed. Estimates of future cash flows and collateral values require significant judgments and may be volatile. General allowances for unimpaired loans are based on an estimated loss rate by loan class. The appropriate historical gross loss rate for each loan class is determined by the greater of the current loss rate based on the most recent twelve months or a ten-year average gross loss rate. Recoveries are not directly considered in the estimation of historical loss rates. Recoveries generally do not follow predictable patterns and are not received until well-after the charge-off date as a result of protracted legal actions. For risk graded loans, historical gross loss rates are adjusted for changes in risk grading. For each loan class, the current weighted average risk grade is compared to the long-term weighted average risk grade. This comparison determines whether credit risk in each loan class is increasing or decreasing. Historical loss rates are adjusted upward or downward in proportion to changes in average risk grading. General allowances for unimpaired loans also consider inherent risks identified for each loan class. Inherent risks consider loss rates that most appropriately represent the current credit cycle and other factors attributable to a specific loan class which have not yet been represented in the historical gross loss rates or risk grading. These factors include changes in commodity prices or engineering imprecision which may affect the value of reserves that secure our energy loan portfolio, construction risk that may affect commercial real estate loans, changes in regulations and public policy that may disproportionately impact health care loans and changes in loan products. Nonspecific allowances are maintained for risks beyond factors specific to a particular portfolio segment or loan class. These factors include trends in the economy in our primary lending areas, concentration in large-balance loans and other relevant factors. An accrual for off-balance sheet credit risk is included in Other liabilities. The appropriateness of the accrual is determined in the same manner as the allowance for loan losses. A provision for credit losses is charged against or credited to earnings in amounts necessary to maintain an appropriate Allowance for Credit Losses. Recoveries of loans previously charged off are added to the allowance when received. Transfers of Financial Assets BOK Financial regularly transfers financial assets as part of its mortgage banking activities and periodically may transfer other financial assets. Transfers are recorded as sales when the criteria for surrender of control are met. The Company has elected to carry certain residential mortgage loans held for sale at fair value under the fair value option. Changes in fair value are recognized in net income as they occur. These loans are reported separately in the Consolidated Balance Sheets and changes in fair value are recorded in other operating revenue - mortgage banking revenue in the Consolidated Statements of Earnings. Fair value of conforming residential mortgage loans that will be sold to U.S. government agencies is based on sales commitments or market quotes considered Level 2 inputs. Fair value of mortgage loans that are unable to be sold to U.S. government agencies is based on Level 3 inputs using quoted prices of loans that are sold in securitization transactions with a liquidity discount applied. The fair value is corroborated with an independent third party on at least an annual basis. BOK Financial retains a repurchase obligation under underwriting representations and warranties related to residential mortgage loans transferred and generally retains the right to service the loans. The Company may incur a recourse obligation in limited circumstances. Separate accruals are recognized in Other liabilities in the Consolidated Balance Sheets for repurchase and recourse obligations. These reserves reflect the estimated amount of probable loss the Company will incur as a result of repurchasing a loan, indemnifications, and other settlement resolutions. Repurchases of loans with an origination defect that are also credit impaired are considered collateral dependent and are initially recognized at net realizable value (appraised value less the cost to sell). The difference between unpaid principal balance and net realizable value is not accreted. Repurchases of loans with an origination defect that are not credit impaired are carried at fair value as of the repurchase date. Interest income continues to accrue on these loans and the discount is accreted over the estimated life of the loan. The accrual for credit losses related to recourse loans for principal and interest is performed by Credit Administration and subject to oversight by the Finance/Credit Administration Allowance Committee. All other mortgage related accruals are reviewed monthly by the Mortgage Contingency Loss Accrual Committee which is subject to oversight by Finance. The Company may also choose to purchase GNMA loans once certain mandated delinquency criteria are met. The loans that are eligible and are chosen to be repurchased are initially recognized at fair value based on expected cash flow discounted using the average agency guaranteed debenture rates, average actual principal loss rates and liquidity premium. The Company may also retain a residual interest in excess cash flows generated by the assets. All assets obtained, including cash, servicing rights and residual interests, and all liabilities incurred, including recourse obligations, are initially recognized at fair value, all assets transferred are de-recognized and any gain or loss on the sale is recognized in earnings. Subsequently, servicing rights and residual interest are carried at fair value with changes in fair value recognized in earnings as they occur. Real Estate and Other Repossessed Assets Real estate and other repossessed assets are acquired in partial or total forgiveness of loans. These assets are initially recognized at cost, which is determined by fair value at date of foreclosure less estimated disposal costs. They are subsequently carried at the lower of cost or current fair value less estimated disposal costs. Decreases in fair value below cost are recognized as asset-specific valuation allowances which may be reversed when supported by future increases in fair value. Subsequent increases in fair value may be used to reduce the allowance but not below zero. Fair values of real estate are based on “as is” appraisals which are updated at least annually or more frequently for certain asset types or assets located in certain distressed markets. Fair values based on appraisals are generally considered to be based on significant other observable inputs. The Company also considers decreases in listing price and other relevant information in quarterly evaluations and reduces the carrying value of real estate and other repossessed assets when necessary. Fair values based on list prices and other relevant information are generally considered to be based on significant unobservable inputs. Additional costs incurred to complete real estate and other repossessed assets may increase the carrying value, up to current fair value based on “as completed” appraisals. The fair value of mineral rights included in repossessed assets are generally determined by our internal staff of engineers based on projected cash flows from proven oil and gas reserves under existing economic and operating conditions. The value of other repossessed assets is generally determined by our special assets staff based on projected liquidation cash flows under current market conditions. Income generated by these assets is recognized as received. Operating expenses are recognized as incurred. Gains or losses on sales of real estate and other repossessed assets are based on the cash proceeds received less the cost basis of the asset, net of any valuation allowances. The estimated disposal costs of real estate and other repossessed assets are evaluated by the Company on an annual basis based on actual results. Premises and Equipment Premises and equipment are carried at cost, including capitalized interest when appropriate, less accumulated depreciation and amortization. Depreciation and amortization are computed on a straight-line basis over the estimated useful lives of the assets or, for leasehold improvements, over the shorter of the estimated useful lives or remaining lease terms. Useful lives range from 5 years to 40 years for buildings and improvements, 3 years to 10 years for software and 3 years to 10 years for furniture and equipment. Construction in progress represents facilities construction and data processing systems projects underway that have not yet been placed into service. Depreciation and amortization begin once the assets are placed into service. Repair and maintenanc

Securities

Securities	12 Months Ended
	Dec. 31, 2016
Marketable Securities [Abstract]
Securities [Text Block]	Securities Trading Securities The fair value and net unrealized gain (loss) included in trading securities is as follows (in thousands): December 31, 2016 December 31, 2015 Fair Value Net Unrealized Gain (Loss) Fair Value Net Unrealized Gain (Loss) U.S. government agency debentures $ 6,234 $ (4 ) $ 61,295 $ (71 ) U.S. government agency residential mortgage-backed securities 310,067 635 10,989 17 Municipal and other tax-exempt securities 14,427 50 31,901 210 Other trading securities 6,900 57 18,219 (16 ) Total trading securities $ 337,628 $ 738 $ 122,404 $ 140 Investment Securities The amortized cost and fair values of investment securities are as follows (in thousands): December 31, 2016 Amortized Carrying Fair Gross Unrealized 1 Cost Value Value Gain Loss Municipal and other tax-exempt securities $ 320,364 $ 320,364 $ 321,225 $ 2,272 $ (1,411 ) U.S. government agency residential mortgage-backed securities – Other 20,777 20,777 21,473 767 (71 ) Other debt securities 205,004 205,004 222,795 18,115 (324 ) Total investment securities $ 546,145 $ 546,145 $ 565,493 $ 21,154 $ (1,806 ) 1 Gross unrealized gains and losses are not recognized in AOCI in the Consolidated Balance Sheets. December 31, 2015 Amortized Carrying Fair Gross Unrealized 1 Cost Value Value Gain Loss Municipal and other tax-exempt securities $ 365,258 $ 365,258 $ 368,910 $ 3,935 $ (283 ) U.S. government agency residential mortgage-backed securities – Other 26,721 26,833 27,874 1,063 (22 ) Other debt securities 205,745 205,745 232,375 26,689 (59 ) Total investment securities $ 597,724 $ 597,836 $ 629,159 $ 31,687 $ (364 ) 1 Gross unrealized gains and losses are not recognized in AOCI in the Consolidated Balance Sheets. The amortized cost and fair values of investment securities at December 31, 2016 , by contractual maturity, are as shown in the following table (dollars in thousands): Less than One Year One to Five Years Six to Ten Years Over Ten Years Total Weighted Average Maturity² Municipal and other tax-exempt securities: Carrying value $ 83,583 $ 181,596 $ 5,909 $ 49,276 $ 320,364 3.41 Fair value 83,544 180,993 5,836 50,852 321,225 Nominal yield¹ 1.48 % 2.08 % 3.31 % 5.20 % 2.43 % Other debt securities: Carrying value $ 16,045 $ 41,804 $ 127,320 $ 19,835 $ 205,004 6.66 Fair value 16,107 44,372 142,010 20,306 222,795 Nominal yield 3.28 % 5.14 % 5.86 % 4.79 % 5.41 % Total fixed maturity securities: Carrying value $ 99,628 $ 223,400 $ 133,229 $ 69,111 $ 525,368 4.68 Fair value 99,651 225,365 147,846 71,158 544,020 Nominal yield 1.77 % 2.65 % 5.75 % 5.08 % 3.59 % Residential mortgage-backed securities: Carrying value $ 20,777 ³ Fair value 21,473 Nominal yield 4 2.76 % Total investment securities: Carrying value $ 546,145 Fair value 565,493 Nominal yield 3.56 % 1 Calculated on a taxable equivalent basis using a 39% effective tax rate. 2 Expected maturities may differ from contractual maturities because borrowers may have the right to call or prepay obligations with or without penalty. 3 The average expected lives of residential mortgage-backed securities were 4.7 years based upon current prepayment assumptions. 4 The nominal yield on residential mortgage-backed securities is based upon prepayment assumptions at the purchase date. Actual yields earned may differ significantly based upon actual prepayments. See Quarterly Financial Summary - Unaudited for current yields on the investment securities portfolio. Available for Sale Securities The amortized cost and fair value of available for sale securities are as follows (in thousands): December 31, 2016 Amortized Fair Gross Unrealized 1 Cost Value Gain Loss OTTI ² U.S. Treasury securities $ 1,000 $ 999 $ — $ (1 ) $ — Municipal and other tax-exempt securities 41,050 40,993 343 (400 ) — Residential mortgage-backed securities: U.S. government agencies: FNMA 3,062,525 3,055,676 25,066 (31,915 ) — FHLMC 1,534,451 1,531,116 8,475 (11,810 ) — GNMA 878,375 873,594 2,259 (7,040 ) — Total U.S. government agencies 5,475,351 5,460,386 35,800 (50,765 ) — Private issue: Alt-A loans 44,245 51,512 7,485 — (218 ) Jumbo-A loans 56,947 64,023 7,092 (16 ) — Total private issue 101,192 115,535 14,577 (16 ) (218 ) Total residential mortgage-backed securities 5,576,543 5,575,921 50,377 (50,781 ) (218 ) Commercial mortgage-backed securities guaranteed by U.S. government agencies 3,035,750 3,017,933 5,472 (23,289 ) — Other debt securities 4,400 4,152 — (248 ) — Perpetual preferred stock 15,561 18,474 2,913 — — Equity securities and mutual funds 17,424 18,357 1,060 (127 ) — Total available for sale securities $ 8,691,728 $ 8,676,829 $ 60,165 $ (74,846 ) $ (218 ) 1 Gross unrealized gain/loss recognized in AOCI in the consolidated balance sheet. 2 Amounts represent unrealized loss that remains in AOCI after an other-than-temporary credit loss has been recognized in income. December 31, 2015 Amortized Fair Gross Unrealized¹ Cost Value Gain Loss OTTI ² U.S. Treasury securities $ 1,000 $ 995 $ — $ (5 ) $ — Municipal and other tax-exempt securities 56,681 56,817 873 (737 ) — Residential mortgage-backed securities: U.S. government agencies: FNMA 3,156,214 3,187,215 41,502 (10,501 ) — FHLMC 1,940,915 1,949,335 14,727 (6,307 ) — GNMA 763,967 761,801 2,385 (4,551 ) — Total U.S. government agencies 5,861,096 5,898,351 58,614 (21,359 ) — Private issue: Alt-A loans 56,387 62,574 6,574 — (387 ) Jumbo-A loans 71,724 76,544 5,260 — (440 ) Total private issue 128,111 139,118 11,834 — (827 ) Total residential mortgage-backed securities 5,989,207 6,037,469 70,448 (21,359 ) (827 ) Commercial mortgage-backed securities guaranteed by U.S. government agencies 2,919,044 2,905,796 5,396 (18,644 ) — Other debt securities 4,400 4,151 — (249 ) — Perpetual preferred stock 17,171 19,672 2,501 — — Equity securities and mutual funds 17,121 17,833 752 (40 ) — Total available for sale securities $ 9,004,624 $ 9,042,733 $ 79,970 $ (41,034 ) $ (827 ) 1 Gross unrealized gain/loss recognized in AOCI in the consolidated balance sheet. 2 Amounts represent unrealized loss that remains in AOCI after an other-than-temporary credit loss has been recognized in income. The amortized cost and fair values of available for sale securities at December 31, 2016 , by contractual maturity, are as shown in the following table (dollars in thousands): Less than One Year One to Five Years Six to Ten Years Over Ten Years Total Weighted Average Maturity 5 U.S. Treasury securities: Amortized cost $ — $ 1,000 $ — $ — $ 1,000 1.04 Fair value — 999 — — 999 Nominal yield — % 0.87 % — % — % 0.87 % Municipal and other tax-exempt securities: Amortized cost 9,848 12,254 2,103 16,845 41,050 7.95 Fair value 9,903 12,399 2,151 16,540 40,993 Nominal yield¹ 4.81 % 4.01 % 3.47 % 2.28 % 6 3.46 % Commercial mortgage-backed securities: Amortized cost 31,910 921,981 1,832,535 249,324 3,035,750 6.90 Fair value 31,856 920,108 1,820,627 245,342 3,017,933 Nominal yield 1.00 % 1.79 % 1.85 % 1.82 % 1.81 % Other debt securities: Amortized cost — — — 4,400 4,400 30.66 Fair value — — — 4,152 4,152 Nominal yield — % — % — % 1.71 % 1.71 % Total fixed maturity securities: Amortized cost $ 41,758 $ 935,235 $ 1,834,638 $ 270,569 $ 3,082,200 6.95 Fair value 41,759 933,506 1,822,778 266,034 3,064,077 Nominal yield 1.89 % 1.82 % 1.85 % 1.84 % 1.83 % Residential mortgage-backed securities: Amortized cost $ 5,576,543 2 Fair value 5,575,921 Nominal yield 4 1.86 % Perpetual preferred stock. equity securities and mutual funds: Amortized cost $ 32,985 ³ Fair value 36,831 Nominal yield — % Total available-for-sale securities: Amortized cost $ 8,691,728 Fair value 8,676,829 Nominal yield 1.84 % 1 Calculated on a taxable equivalent basis using a 39% effective tax rate. 2 The average expected lives of mortgage-backed securities were 3.9 years based upon current prepayment assumptions. 3 Primarily common stock and preferred stock of corporate issuers with no stated maturity. 4 The nominal yield on mortgage-backed securities is based upon prepayment assumptions at the purchase date. Actual yields earned may differ significantly based upon actual prepayments. See Quarterly Financial Summary –– Unaudited following for current yields on available for sale securities portfolio. 5 Expected maturities may differ from contractual maturities, because borrowers may have the right to call or prepay obligations with or without penalty. 6 Nominal yield on municipal and other tax-exempt securities and other debt securities with contractual maturity dates over ten years are based on variable rates which generally are reset within 35 days . Sales of available for sale securities resulted in gains and losses as follows (in thousands): Year Ended December 31, 2016 2015 2014 Proceeds $ 899,381 $ 1,600,380 2,664,740 Gross realized gains 11,696 15,849 24,923 Gross realized losses (21 ) (3,791 ) (23,384 ) Related federal and state income tax expense 4,542 4,691 599 A summary of investment and available for sale securities that have been pledged as collateral for repurchase agreements, public trust funds on deposit and for other purposes, as required by law was as follows (in thousands): December 31, 2016 2015 Investment: Carrying value $ 322,208 $ 231,033 Fair value 323,808 234,382 Available for sale: Amortized cost 7,353,116 6,831,743 Fair value 7,327,470 6,849,524 The secured parties do not have the right to sell or re-pledge these securities. Temporarily Impaired Securities as of December 31, 2016 (In thousands) Number of Securities Less Than 12 Months 12 Months or Longer Total Fair Value Unrealized Loss Fair Value Unrealized Loss Fair Value Unrealized Loss Investment: Municipal and other tax-exempt securities 151 $ 219,892 $ 1,316 $ 4,333 $ 95 $ 224,225 $ 1,411 U.S. government agency residential mortgage-backed securities – Other 1 4,358 71 — — 4,358 71 Other debt securities 41 11,820 322 855 2 12,675 324 Total investment securities 193 $ 236,070 $ 1,709 $ 5,188 $ 97 $ 241,258 $ 1,806 Number of Securities Less Than 12 Months 12 Months or Longer Total Fair Value Unrealized Loss Fair Value Unrealized Loss Fair Value Unrealized Loss Available for sale: U.S. Treasury securities 1 $ 999 $ 1 $ — $ — $ 999 $ 1 Municipal and other tax-exempt securities 24 $ 15,666 $ 22 $ 4,689 $ 378 20,355 400 Residential mortgage-backed securities: U.S. government agencies: FNMA 91 1,787,644 30,238 72,105 1,677 1,859,749 31,915 FHLMC 58 964,017 11,210 18,307 600 982,324 11,810 GNMA 31 548,637 6,145 25,796 895 574,433 7,040 Total U.S. agencies 180 3,300,298 47,593 116,208 3,172 3,416,506 50,765 Private issue 1 : Alt-A loans 5 7,931 174 7,410 44 15,341 218 Jumbo-A loans 1 — — 6,098 16 6,098 16 Total private issue 6 7,931 174 13,508 60 21,439 234 Total residential mortgage-backed securities 186 3,308,229 47,767 129,716 3,232 3,437,945 50,999 Commercial mortgage-backed securities guaranteed by U.S. government agencies 171 1,904,584 22,987 38,875 302 1,943,459 23,289 Other debt securities 2 — — 4,152 248 4,152 248 Perpetual preferred stock — — — — — — — Equity securities and mutual funds 104 2,127 41 817 86 2,944 127 Total available for sale securities 488 $ 5,231,605 $ 70,818 $ 178,249 $ 4,246 $ 5,409,854 $ 75,064 1 Includes securities for which an unrealized loss remains in AOCI after an other-than-temporary credit loss has been recognized in income. Temporarily Impaired Securities as of December 31, 2015 (In thousands) Number of Securities Less Than 12 Months 12 Months or Longer Total Fair Value Unrealized Loss Fair Value Unrealized Loss Fair Value Unrealized Loss Investment: Municipal and other tax- exempt securities 73 $ 127,319 $ 206 $ 13,380 $ 77 $ 140,699 $ 283 U.S. government agency residential mortgage-backed securities – Other 1 5,533 22 — — 5,533 22 Other debt securities 11 1,082 41 1,715 18 2,797 59 Total investment securities 85 $ 133,934 $ 269 $ 15,095 $ 95 $ 149,029 $ 364 Number of Securities Less Than 12 Months 12 Months or Longer Total Fair Value Unrealized Loss Fair Value Unrealized Loss Fair Value Unrealized Loss Available for sale: U.S. Treasury securities 1 $ 995 $ 5 $ — $ — $ 995 $ 5 Municipal and other tax-exempt securities 20 $ 9,909 $ 27 $ 11,664 $ 710 21,573 737 Residential mortgage-backed securities: U. S. government agencies: FNMA 55 1,188,022 10,262 18,236 239 1,206,258 10,501 FHLMC 40 726,713 4,827 77,545 1,480 804,258 6,307 GNMA 15 364,919 1,951 102,109 2,600 467,028 4,551 Total U.S. agencies 110 2,279,654 17,040 197,890 4,319 2,477,544 21,359 Private issue 1 : Alt-A loans 4 — — 9,264 387 9,264 387 Jumbo-A loans 8 — — 8,482 440 8,482 440 Total private issue 12 — — 17,746 827 17,746 827 Total residential mortgage-backed securities 122 2,279,654 17,040 215,636 5,146 2,495,290 22,186 Commercial mortgage-backed securities guaranteed by U.S. government agencies 213 1,582,469 11,419 484,258 7,225 2,066,727 18,644 Other debt securities 2 — — 4,151 249 4,151 249 Perpetual preferred stock — — — — — — — Equity securities and mutual funds 61 782 5 991 35 1,773 40 Total available for sale securities 419 $ 3,873,809 $ 28,496 $ 716,700 $ 13,365 $ 4,590,509 $ 41,861 1 Includes securities for which an unrealized loss remains in AOCI after an other-than-temporary credit loss has been recognized in income. For debt securities, management determines whether it intends to sell or if it is more-likely-than-not that it will be required to sell impaired securities. Based on this evaluation as of December 31, 2016 , we do not intend to sell any impaired available for sale securities before fair value recovers to our current amortized cost and it is more-likely-than-not that we will not be required to sell impaired securities before fair value recovers, which may be maturity. At December 31, 2016 , the composition of the Company’s investment and available for sale securities portfolios by the lowest current credit rating assigned by any of the three nationally-recognized rating agencies is as follows (in thousands): AAA - AA A - BBB Below Investment Grade Not Rated Total Carrying Value Fair Value Carrying Value Fair Value Carrying Value Fair Value Carrying Value Fair Value Carrying Value Fair Value Investment: Municipal and other tax-exempt $ 193,931 $ 193,834 $ 6,028 $ 6,037 $ — $ — $ 120,405 $ 121,354 $ 320,364 $ 321,225 U.S. government agency residential mortgage-backed securities 1 — — — — — — 20,777 21,473 20,777 21,473 Other debt securities 140,184 156,641 — — — — 64,820 66,154 205,004 222,795 Total investment securities $ 334,115 $ 350,475 $ 6,028 $ 6,037 $ — $ — $ 206,002 $ 208,981 $ 546,145 $ 565,493 AAA - AA A - BBB Below Investment Grade Not Rated Total Amortized Cost Fair Value Amortized Cost Fair Value Amortized Cost Fair Value Amortized Cost Fair Value Amortized Cost Fair Value Available for Sale: U.S. Treasury securities $ — $ — $ — $ — $ — $ — $ 1,000 $ 999 $ 1,000 $ 999 Municipal and other tax-exempt 23,343 23,657 5,595 5,237 — — 12,112 12,099 41,050 40,993 U.S. government agency residential mortgage-backed securities 1 — — — — — — 5,475,351 5,460,386 5,475,351 5,460,386 Privately issued residential mortgage-backed securities — — — — 101,192 115,535 — — 101,192 115,535 Commercial mortgage-backed securities guaranteed by U.S. government agencies — — — — — — 3,035,750 3,017,933 3,035,750 3,017,933 Other debt securities 4,400 4,152 — — — — — — 4,400 4,152 Perpetual preferred stock — — 4,796 5,177 10,765 13,297 — — 15,561 18,474 Equity securities and mutual funds 4 759 — — — — 17,420 17,598 17,424 18,357 Total available for sale securities $ 27,747 $ 28,568 $ 10,391 $ 10,414 $ 111,957 $ 128,832 $ 8,541,633 $ 8,509,015 $ 8,691,728 $ 8,676,829 1 U.S. government and government sponsored enterprises are not rated by the nationally-recognized rating agencies as these securities are guaranteed by agencies of the U.S. government or government-sponsored enterprises. At December 31, 2016 , the entire portfolio of privately issued residential mortgage-backed securities was rated below investment grade by at least one of the nationally-recognized rating agencies. The gross unrealized loss on these securities totaled $234 thousand . Impairment of these securities was evaluated based on projections of estimated cash flows. The primary assumptions used in this evaluation were: December 31, 2016 2015 Unemployment rate Decreasing to 4.6% over the next 12 months and remain at 4.6% thereafter. Decreasing to 4.8% over the next 12 months and remain at 4.8% thereafter. Housing price appreciation/depreciation Starting with current depreciated housing prices based on information derived from the FHFA 1 , appreciating 3.1% over the next 12 months, then flat for the following 12 months and then appreciating at 2% per year thereafter. Starting with current depreciated housing prices based on information derived from the FHFA 1 , appreciating 3.5% over the next 12 months, then flat for the following 12 months and then appreciating at 2% per year thereafter. Estimated liquidation costs Reflect actual historical liquidations costs observed on Jumbo and Alt-A residential mortgage loans in securities owned by the Company. Reflect actual historical liquidations costs observed on Jumbo and Alt-A residential mortgage loans in securities owned by the Company. Discount rates Estimated cash flows were discounted at rates that range from 2.00% to 6.25% based on our current expected yields. Estimated cash flows were discounted at rates that range from 2.00% to 6.25% based on our current expected yields. 1 Federal Housing Finance Agency The Company recognized no credit loss impairment on private-label residential mortgage-backed securities in earnings during 2016 . Credit loss impairment of $157 thousand was recognized in earnings on private-label residential mortgage-backed securities in 2015 and none was recognized in 2014 . Impaired equity securities, including perpetual preferred stocks, are evaluated based on management's ability and intent to hold the securities until fair value recovers. Based on this evaluation, no other-than-temporary impairment losses were recorded in earnings on equity securities during 2016 . A $1.7 million other-than-temporary impairment loss related to equity securities was recorded in earnings in 2015 and $373 thousand in impairment losses were recognized on equity securities in 2014 . The following is a tabular roll forward of the amount of credit-related OTTI recognized on available for sale debt securities in earnings (in thousands): Year Ended December 31, 2016 2015 2014 Balance of credit-related OTTI recognized on available for sale debt, beginning of period $ 54,504 $ 54,347 $ 67,346 Additions for credit-related OTTI not previously recognized — — — Additions for increases in credit-related OTTI previously recognized when there is no intent to sell and no requirement to sell before recovery of amortized cost — 157 — Reductions for change in intent to hold before recovery — — — Sales — — (12,999 ) Balance of credit-related OTTI recognized on available for sale debt securities, end of period $ 54,504 $ 54,504 $ 54,347 Fair Value Option Securities Fair value option securities represent securities which the Company has elected to carry at fair value and separately identified on the Consolidated Balance Sheets with changes in the fair value recognized in earnings as they occur. Certain residential mortgage-backed securities issued by U.S. government agencies and derivative contracts are held as an economic hedge of the mortgage servicing rights. The fair value and net unrealized gain (loss) included in Fair value option securities is as follows (in thousands): December 31, 2016 December 31, 2015 Fair Value Net Unrealized Gain (Loss) Fair Value Net Unrealized Gain (Loss) U.S. government agency residential mortgage-backed securities $ 77,046 $ (1,777 ) $ 444,217 $ (2,060 ) Restricted Equity Securities Restricted equity securities include stock we are required to hold as members of the Federal Reserve system and the Federal Home Loan Banks ("FHLB"). Restricted equity securities are carried at cost as these securities do not have a readily determined fair value because ownership of these shares is restricted and they lack a market. A summary of restricted equity securities follows (in thousands): December 31, 2016 2015 Federal Reserve Bank stock $ 36,498 $ 36,148 Federal Home Loan Bank stock 270,541 237,365 Other 201 171 Total $ 307,240 $ 273,684

Derivatives

Derivatives	12 Months Ended
	Dec. 31, 2016
Derivative Instrument Detail [Abstract]
Derivatives [Text Block]	Derivatives The following table summarizes the fair values of derivative contracts recorded as “derivative contracts” assets and liabilities in the balance sheet at December 31, 2016 (in thousands): Assets Notional 1 Gross Fair Value Netting Adjustments Net Fair Value Before Cash Collateral Cash Collateral Fair Value Net of Cash Collateral Customer risk management programs: Interest rate contracts To-be-announced residential mortgage-backed securities $ 16,949,152 $ 180,695 $ (60,555 ) $ 120,140 $ — $ 120,140 Interest rate swaps 1,403,408 34,442 — 34,442 (4,567 ) 29,875 Energy contracts 835,566 64,140 (28,298 ) 35,842 (71 ) 35,771 Agricultural contracts 53,209 1,382 (515 ) 867 — 867 Foreign exchange contracts 580,886 494,349 — 494,349 (5,183 ) 489,166 Equity option contracts 100,924 4,357 — 4,357 (730 ) 3,627 Total customer risk management programs 19,923,145 779,365 (89,368 ) 689,997 (10,551 ) 679,446 Internal risk management programs 2,514,169 10,426 — 10,426 — 10,426 Total derivative contracts $ 22,437,314 $ 789,791 $ (89,368 ) $ 700,423 $ (10,551 ) $ 689,872 Liabilities Notional¹ Gross Fair Value Netting Adjustments Net Fair Value Before Cash Collateral Cash Collateral Fair Value Net of Cash Collateral Customer risk management programs: Interest rate contracts To-be-announced residential mortgage-backed securities $ 16,637,532 $ 176,928 $ (60,555 ) $ 116,373 $ — $ 116,373 Interest rate swaps 1,403,408 34,442 — 34,442 (11,977 ) 22,465 Energy contracts 820,365 64,306 (28,298 ) 36,008 (31,534 ) 4,474 Agricultural contracts 53,216 1,365 (515 ) 850 (769 ) 81 Foreign exchange contracts 580,712 494,695 — 494,695 (3,630 ) 491,065 Equity option contracts 100,924 4,357 — 4,357 — 4,357 Total customer risk management programs 19,596,157 776,093 (89,368 ) 686,725 (47,910 ) 638,815 Internal risk management programs 2,582,202 25,716 — 25,716 — 25,716 Total derivative contracts $ 22,178,359 $ 801,809 $ (89,368 ) $ 712,441 $ (47,910 ) $ 664,531 1 Notional amounts for commodity contracts are converted into dollar-equivalent amounts based on dollar prices at the inception of the contract. When bilateral netting agreements exist between the Company and its counterparties that create a single legal claim or obligation to pay or receive the net amount in settlement of the individual derivative contracts, the Company reports derivative assets and liabilities on a net by counterparty basis. Contracts may also require the Company to provide or receive cash margin as collateral for derivative assets and liabilities. Derivative assets and liabilities are reported net of cash margin when certain conditions are met. The following table summarizes the fair values of derivative contracts recorded as “derivative contracts” assets and liabilities in the balance sheet at December 31, 2015 (in thousands): Assets Notional 1 Gross Fair Value Netting Adjustments Net Fair Value Before Cash Collateral Cash Collateral Fair Value Net of Cash Collateral Customer risk management programs: Interest rate contracts To-be-announced residential mortgage-backed securities $ 14,583,052 $ 43,270 $ (28,305 ) $ 14,965 $ — $ 14,965 Interest rate swaps 1,332,044 31,744 — 31,744 (1,424 ) 30,320 Energy contracts 470,613 83,045 (22,970 ) 60,075 (18,606 ) 41,469 Agricultural contracts 61,662 2,591 (1,158 ) 1,433 — 1,433 Foreign exchange contracts 546,572 498,830 — 498,830 (4,140 ) 494,690 Equity option contracts 137,278 3,780 — 3,780 (470 ) 3,310 Total customer risk management programs 17,131,221 663,260 (52,433 ) 610,827 (24,640 ) 586,187 Internal risk management programs 22,000 83 — 83 — 83 Total derivative contracts $ 17,153,221 $ 663,343 $ (52,433 ) $ 610,910 $ (24,640 ) $ 586,270 Liabilities Notional¹ Gross Fair Value Netting Adjustments Net Fair Value Before Cash Collateral Cash Collateral Fair Value Net of Cash Collateral Customer risk management programs: Interest rate contracts To-be-announced residential mortgage-backed securities $ 14,168,927 $ 40,141 $ (28,305 ) $ 11,836 $ (1,308 ) $ 10,528 Interest rate swaps 1,332,044 31,928 — 31,928 (20,530 ) 11,398 Energy contracts 463,703 81,869 (22,970 ) 58,899 — 58,899 Agricultural contracts 61,657 2,579 (1,158 ) 1,421 (1,248 ) 173 Foreign exchange contracts 546,405 498,574 — 498,574 (1,951 ) 496,623 Equity option contracts 137,278 3,780 — 3,780 — 3,780 Total customer risk management programs 16,710,014 658,871 (52,433 ) 606,438 (25,037 ) 581,401 Internal risk management programs 75,000 300 — 300 — 300 Total derivative contracts $ 16,785,014 $ 659,171 $ (52,433 ) $ 606,738 $ (25,037 ) $ 581,701 1 Notional amounts for commodity contracts are converted into dollar-equivalent amounts based on dollar prices at the inception of the contract. The following summarizes the pre-tax net gains (losses) on derivative instruments and where they are recorded in the Consolidated Statement of Earnings (in thousands): Year Ended December 31, 2016 2015 2014 Brokerage and Trading Revenue Gain (Loss) on Derivatives, Net Brokerage and Trading Revenue Gain (Loss) on Derivatives, Net Brokerage and Trading Revenue Gain (Loss) on Derivatives, Net Customer risk management programs: Interest rate contracts To-be-announced residential mortgage-backed securities $ 38,523 $ — $ 33,877 $ — $ 27,007 $ — Interest rate swaps 2,589 — 2,066 — 2,494 — Energy contracts 5,027 — 4,060 — 6,572 — Agricultural contracts 111 — 123 — 146 — Foreign exchange contracts 945 — 797 — 1,581 — Equity option contracts — — — — — — Total customer risk management programs 47,195 — 40,923 — 37,800 — Internal risk management programs (4,592 ) (15,685 ) (209 ) 430 — 2,776 Total derivative contracts $ 42,603 $ (15,685 ) $ 40,714 $ 430 $ 37,800 $ 2,776 As discussed in Note 7 , certain derivative contracts not designated as hedging instruments related to mortgage loan commitments and forward sales contracts are included in Residential mortgage loans held for sale on the Consolidated Balance Sheets. See Note 7 for additional discussion of notional, fair value and impact on earnings of these contracts. Forward sales contracts are not considered swaps under the Commodity and Futures Trading Commission final rules. No derivative contracts have been designated as hedging instruments for financial reporting purposes.

Loans and Allowances for Credit

Loans and Allowances for Credit Losses	12 Months Ended
	Dec. 31, 2016
Loans Receivable, Net [Abstract]
Loans [Text Block]	Loans and Allowances for Credit Losses The portfolio segments of the loan portfolio are as follows (in thousands): December 31, 2016 December 31, 2015 Fixed Rate Variable Rate Non-accrual Total Fixed Rate Variable Rate Non-accrual Total Commercial $ 2,327,085 $ 7,884,786 $ 178,953 $ 10,390,824 $ 1,850,548 $ 8,325,559 $ 76,424 $ 10,252,531 Commercial real estate 624,187 3,179,338 5,521 3,809,046 627,678 2,622,354 9,001 3,259,033 Residential mortgage 1,647,357 256,255 46,220 1,949,832 1,598,992 216,661 61,240 1,876,893 Personal 154,971 684,697 290 839,958 91,816 460,418 463 552,697 Total $ 4,753,600 $ 12,005,076 $ 230,984 $ 16,989,660 $ 4,169,034 $ 11,624,992 $ 147,128 $ 15,941,154 Accruing loans past due (90 days) 1 $ 5 $ 1,207 Foregone interest on nonaccrual loans $ 15,990 $ 7,432 1 Excludes residential mortgage loans guaranteed by agencies of the U.S. government. At December 31, 2016 , loans to businesses and individuals with collateral primarily located in Texas totaled $5.4 billion or 32% of the total loan portfolio. Loans to businesses and individuals with collateral primarily located in Oklahoma totaled $3.5 billion or 21% of our total loan portfolio. Loans for which the collateral location is not relevant, such as unsecured loans and reserve-based energy loans, are distributed by the borrower’s primary operating location. These geographic concentrations subject the loan portfolio to the general economic conditions within these areas. At December 31, 2015 , loans to businesses and individuals with collateral primarily located in Texas totaled $5.3 billion or 33% of the loan portfolio and loans to businesses and individuals with collateral primarily located in Oklahoma totaled $3.9 billion or 24% of the loan portfolio. Commercial Commercial loans represent loans for working capital, facilities acquisition or expansion, purchases of equipment and other needs of commercial customers primarily located within our geographical footprint. Commercial loans are underwritten individually and represent on-going relationships based on a thorough knowledge of the customer, the customer’s industry and market. While commercial loans are generally secured by the customer’s assets including real property, inventory, accounts receivable, operating equipment, interest in mineral rights and other property and may also include personal guarantees of the owners and related parties, the primary source of repayment of the loans is the on-going cash flow from operations of the customer’s business. Inherent lending risk is centrally monitored on a continuous basis from underwriting throughout the life of the loan for compliance with commercial lending policies. At December 31, 2016 , commercial loans with collateral primarily located in Texas totaled $3.3 billion or 32% of the commercial loan portfolio segment and commercial loans with collateral primarily located in Oklahoma totaled $2.1 billion or 21% of the commercial loan portfolio segment. The commercial loan portfolio segment is further divided into loan classes. The services loan class totaled $3.1 billion or 18% of total loans. Approximately $1.4 billion of loans in the services class consisted of loans with individual balances of less than $10 million . Businesses included in the services class include governmental, financial & insurance, educational, religious and not-for-profit and professional/technical services. The energy loan class totaled $2.5 billion or 15% of total loans, including $2.0 billion of outstanding loans to energy producers. Approximately 57% of committed production loans were secured by properties primarily producing oil and 43% are secured by properties producing natural gas. The healthcare loan class totaled $2.2 billion or 13% of total loans. The healthcare loan class consists primarily of loans for the development and operation of senior housing and care facilities, including independent living, assisted living and skilled nursing. Healthcare also includes loans to hospitals and other medical service providers. At December 31, 2015 , commercial loans with collateral primarily located in Texas totaled $3.5 billion or 34% of the commercial loan portfolio segment and commercial loans with collateral primarily located in Oklahoma totaled $2.5 billion or 24% of the commercial loan portfolio segment. The energy loan class totaled $3.1 billion or 19% of total loans, including $2.5 billion of outstanding loans to energy producers. At December 31, 2015 , approximately 62% of committed production loans were secured by properties primarily producing oil and 38% were secured by properties producing natural gas. The services loan class totaled $2.8 billion or 17% of total loans. Approximately $1.2 billion of loans in the services category consisted of loans with individual balances of less than $10 million . The healthcare loan class totaled $1.9 billion or 12% of total loans. Commercial Real Estate Commercial real estate loans are for the construction of buildings or other improvements to real estate and property held by borrowers for investment purposes primarily within our geographical footprint. We require collateral values in excess of the loan amounts, demonstrated cash flows in excess of expected debt service requirements, equity investment in the project and a portion of the project already sold, leased or permanent financing already secured. The expected cash flows from all significant new or renewed income producing property commitments are stress tested to reflect the risks in varying interest rates, vacancy rates and rental rates. As with commercial loans, inherent lending risks are centrally monitored on a continuous basis from underwriting throughout the life of the loan for compliance with applicable lending policies. At December 31, 2016 , 30% of commercial real estate loans are secured by properties primarily located in the Dallas and Houston areas of Texas. An additional 11% of commercial real estate loans are secured by properties located primarily in the Tulsa and Oklahoma City metropolitan areas of Oklahoma. At December 31, 2015 , 30% of commercial real estate loans were secured by properties in Texas, 13% of commercial real estate loans were secured by properties in Oklahoma. Residential Mortgage and Personal Residential mortgage loans provide funds for our customers to purchase or refinance their primary residence or to borrow against the equity in their home. Residential mortgage loans are secured by a first or second mortgage on the customer’s primary residence. Personal loans consist primarily of loans secured by the cash surrender value of insurance policies and marketable securities. It also includes direct loans secured by and for the purchase of automobiles, recreational and marine equipment as well as other unsecured loans. Residential mortgage and personal loans are made in accordance with underwriting policies. Credit scoring is assessed based on significant credit characteristics including credit history, residential and employment stability. Residential mortgage loans retained in the Company’s portfolio are primarily composed of various mortgage programs to support customer relationships including jumbo mortgage loans, non-builder construction loans and special loan programs for high net worth individuals and certain professionals. Jumbo loans may be fixed or variable rate and are fully amortizing. Jumbo loans generally conform to government sponsored entity standards, except that the loan size exceeds maximums required under these standards. These loans generally require a minimum FICO score of 720 and a maximum debt-to-income ratio (“DTI”) of 38% . Loan-to-value (“LTV”) ratios are tiered from 60% to 100% , depending on the market. Special mortgage programs include fixed and variable fully amortizing loans tailored to the needs of certain healthcare professionals. Variable rate loans are fully indexed at origination and may have fixed rates for three to ten years, then adjust annually thereafter. At December 31, 2016 and 2015 , residential mortgage loans included $199 million and $197 million , respectively, of loans guaranteed by U.S. government agencies previously sold into GNMA mortgage pools. These loans either have been repurchased or are eligible to be repurchased by the Company when certain defined delinquency criteria are met. Although payments on these loans generally are past due more than 90 days, interest continues to accrue based on the government guarantee. Home equity loans totaled $744 million at December 31, 2016 and $735 million at December 31, 2015 . At December 31, 2016 , 65% of the home equity loan portfolio was comprised of first lien loans and 35% of the home equity portfolio was comprised of junior lien loans. Junior lien loans were distributed 52% to amortizing term loans and 48% to revolving lines of credit. At December 31, 2015 , 68% of the home equity portfolio was comprised of first lien loans and 32% of the home equity loan portfolio was comprised of junior lien loans. Junior lien loans were distributed 65% to amortizing term loans and 35% to revolving lines of credit. Home equity loans generally require a minimum FICO score of 700 and a maximum DTI of 40%. The maximum loan amount available for our home equity loan products is generally $400 thousand . Revolving loans have a 5 year revolving period followed by 15 year term of amortizing repayments. Interest-only home equity loans may not be extended for any additional revolving time. All other home equity loans may be extended at management's discretion for an additional 5 year revolving term subject to an update of certain credit information. At December 31, 2016 , 33% of residential mortgage loans are secured by properties located in Oklahoma, 29% of residential mortgage loans are secured by properties located in Texas, 10% of residential mortgage are secured by properties located in New Mexico and 10% of residential mortgage are secured by properties located in Colorado. At December 31, 2015 , 37% of residential mortgage loans were secured by properties in Oklahoma, 29% of residential mortgage were secured by properties in Texas, 12% of residential mortgage loans are secured by properties in New Mexico and 9% of residential mortgage loans are secured by properties in Colorado. Credit Commitments Commitments to extend credit are agreements to lend to a customer as long as there is no violation of conditions established in the contract. Commitments generally have fixed expiration dates or other termination clauses and may require payment of a fee. At December 31, 2016 , outstanding commitments totaled $9.4 billion . Because some commitments are expected to expire before being drawn upon, the total commitment amounts do not necessarily represent future cash requirements. BOK Financial uses the same credit policies in making commitments as it does loans. The amount of collateral obtained, if deemed necessary, is based upon management’s credit evaluation of the borrower. Standby letters of credit are conditional commitments issued to guarantee the performance of a customer to a third party. Because the credit risk involved in issuing standby letters of credit is essentially the same as that involved in extending loan commitments, BOK Financial uses the same credit policies in evaluating the creditworthiness of the customer. Additionally, BOK Financial uses the same evaluation process in obtaining collateral on standby letters of credit as it does for loan commitments. The term of these standby letters of credit is defined in each commitment and typically corresponds with the underlying loan commitment. At December 31, 2016 , outstanding standby letters of credit totaled $585 million . Commercial letters of credit are used to facilitate customer trade transactions with the drafts being drawn when the underlying transaction is consummated. At December 31, 2016 , outstanding commercial letters of credit totaled $4.2 million . Allowances for Credit Losses BOK Financial maintains an allowance for loan losses and an accrual for off-balance sheet credit risk. The accrual for off-balance sheet credit risk is maintained at a level that is appropriate to cover estimated losses associated with credit instruments that are not currently recognized as assets such as loan commitments, standby letters of credit or guarantees. As discussed in greater detail in Note 7 , the Company also has separate accruals related to off-balance sheet credit risk related to residential mortgage loans previously sold with full or partial recourse and for residential mortgage loans sold to government sponsored agencies under standard representations and warranties. The allowance for loan losses consists of specific allowances attributed to impaired loans that have not yet been charged down to amounts we expect to recover, general allowances for unimpaired loans based on estimated loss rates by loan class and nonspecific allowances based on general economic conditions, concentration in loans with large balances and other relevant factors. The activity in the allowance for loan losses and the accrual for off-balance sheet credit risk related to loan commitments and standby letters of credit for the year ended December 31, 2016 is summarized as follows (in thousands): Commercial Commercial Real Estate Residential Mortgage Personal Nonspecific Allowance Total Allowance for loan losses: Beginning balance $ 130,334 $ 41,391 $ 19,509 $ 4,164 $ 30,126 $ 225,524 Provision for loan losses 43,980 8,075 (1,972 ) 7,310 (1,926 ) 55,467 Loans charged off (35,828 ) — (1,312 ) (5,448 ) — (42,588 ) Recoveries 1,727 1,283 1,999 2,747 — 7,756 Ending balance $ 140,213 $ 50,749 $ 18,224 $ 8,773 $ 28,200 $ 246,159 Accrual for off-balance sheet credit risk: Beginning balance $ 1,506 $ 153 $ 30 $ 22 $ — $ 1,711 Provision for off-balance sheet credit risk 9,557 (30 ) 20 (14 ) — 9,533 Ending balance $ 11,063 $ 123 $ 50 $ 8 $ — $ 11,244 Total provision for credit losses $ 53,537 $ 8,045 $ (1,952 ) $ 7,296 $ (1,926 ) $ 65,000 The activity in the allowance for loan losses and the accrual for off-balance sheet credit risk related to loan commitments and standby letters of credit for the year ended December 31, 2015 is summarized as follows (in thousands): Commercial Commercial Real Estate Residential Mortgage Personal Nonspecific Allowance Total Allowance for loan losses: Beginning balance $ 90,875 $ 42,445 $ 23,458 $ 4,233 $ 28,045 $ 189,056 Provision for loan losses 43,464 (11,189 ) (3,004 ) 2,167 2,081 33,519 Loans charged off (6,734 ) (944 ) (2,205 ) (5,288 ) — (15,171 ) Recoveries 2,729 11,079 1,260 3,052 — 18,120 Ending balance $ 130,334 $ 41,391 $ 19,509 $ 4,164 $ 30,126 $ 225,524 Accrual for off-balance sheet credit risk: Beginning balance $ 475 $ 707 $ 28 $ 20 $ — $ 1,230 Provision for off-balance sheet credit risk 1,031 (554 ) 2 2 — 481 Ending balance $ 1,506 $ 153 $ 30 $ 22 $ — $ 1,711 Total provision for credit losses $ 44,495 $ (11,743 ) $ (3,002 ) $ 2,169 $ 2,081 $ 34,000 The activity in the allowance for loan losses and the accrual for off-balance sheet credit risk related to loan commitments and standby letters of credit for the year ended December 31, 2014 is summarized as follows (in thousands): Commercial Commercial Real Estate Residential Mortgage Personal Nonspecific Allowance Total Allowance for loan losses: Beginning balance $ 79,180 $ 41,573 $ 29,465 $ 6,965 $ 28,213 $ 185,396 Provision for loan losses 9,561 (4,084 ) (3,559 ) (892 ) (168 ) 858 Loans charged off (3,569 ) (2,047 ) (4,448 ) (6,168 ) — (16,232 ) Recoveries 5,703 7,003 2,000 4,328 — 19,034 Ending balance $ 90,875 $ 42,445 $ 23,458 $ 4,233 $ 28,045 $ 189,056 Accrual for off-balance sheet credit risk: Beginning balance $ 119 $ 1,876 $ 90 $ 3 $ — $ 2,088 Provision for off-balance sheet credit risk 356 (1,169 ) (62 ) 17 — (858 ) Ending balance $ 475 $ 707 $ 28 $ 20 $ — $ 1,230 Total provision for credit losses $ 9,917 $ (5,253 ) $ (3,621 ) $ (875 ) $ (168 ) $ — The allowance for loan losses and recorded investment of the related loans by portfolio segment for each impairment measurement method at December 31, 2016 is as follows (in thousands): Collectively Measured for Impairment Individually Measured for Impairment Total Recorded Investment Related Allowance Recorded Investment Related Allowance Recorded Investment Related Allowance Commercial $ 10,211,871 $ 139,416 $ 178,953 $ 797 $ 10,390,824 $ 140,213 Commercial real estate 3,803,525 50,749 5,521 — 3,809,046 50,749 Residential mortgage 1,903,612 18,178 46,220 46 1,949,832 18,224 Personal 839,668 8,773 290 — 839,958 8,773 Total 16,758,676 217,116 230,984 843 16,989,660 217,959 Nonspecific allowance — — — — — 28,200 Total $ 16,758,676 $ 217,116 $ 230,984 $ 843 $ 16,989,660 $ 246,159 The allowance for loan losses and recorded investment of the related loans by portfolio segment for each impairment measurement method at December 31, 2015 is as follows (in thousands): Collectively Measured for Impairment Individually Measured for Impairment Total Recorded Investment Related Allowance Recorded Investment Related Allowance Recorded Investment Related Allowance Commercial $ 10,176,107 $ 114,027 $ 76,424 $ 16,307 $ 10,252,531 $ 130,334 Commercial real estate 3,250,032 41,373 9,001 18 3,259,033 41,391 Residential mortgage 1,815,653 19,441 61,240 68 1,876,893 19,509 Personal 552,234 4,164 463 — 552,697 4,164 Total 15,794,026 179,005 147,128 16,393 15,941,154 195,398 Nonspecific allowance — — — — — 30,126 Total $ 15,794,026 $ 179,005 $ 147,128 $ 16,393 $ 15,941,154 $ 225,524 Credit Quality Indicators The Company utilizes loan class and risk grading as primary credit quality indicators. Substantially all commercial and commercial real estate loans and certain residential mortgage and personal loans are risk graded based on a quarterly evaluation of the borrowers’ ability to repay the loans. Certain commercial loans and most residential mortgage and personal loans are small, homogeneous pools that are not risk graded. The allowance for loan losses and recorded investment of the related loans by portfolio segment for risk graded and non-risk graded loans at December 31, 2016 is as follows (in thousands): Internally Risk Graded Non-Graded Total Recorded Investment Related Allowance Recorded Investment Related Allowance Recorded Investment Related Allowance Commercial $ 10,360,725 $ 139,293 $ 30,099 $ 920 $ 10,390,824 $ 140,213 Commercial real estate 3,809,046 50,749 — — 3,809,046 50,749 Residential mortgage 243,703 2,893 1,706,129 15,331 1,949,832 18,224 Personal 744,602 5,035 95,356 3,738 839,958 8,773 Total 15,158,076 197,970 1,831,584 19,989 16,989,660 217,959 Nonspecific allowance — — — — — 28,200 Total $ 15,158,076 $ 197,970 $ 1,831,584 $ 19,989 $ 16,989,660 $ 246,159 The allowance for loan losses and recorded investment of the related loans by portfolio segment for risk graded and non-risk graded loans at December 31, 2015 is as follows (in thousands): Internally Risk Graded Non-Graded Total Recorded Investment Related Allowance Recorded Investment Related Allowance Recorded Investment Related Allowance Commercial $ 10,227,303 $ 129,426 $ 25,228 $ 908 $ 10,252,531 $ 130,334 Commercial real estate 3,259,033 41,391 — — 3,259,033 41,391 Residential mortgage 196,701 2,883 1,680,192 16,626 1,876,893 19,509 Personal 467,955 1,390 84,742 2,774 552,697 4,164 Total 14,150,992 175,090 1,790,162 20,308 15,941,154 195,398 Nonspecific allowance — — — — — 30,126 Total $ 14,150,992 $ 175,090 $ 1,790,162 $ 20,308 $ 15,941,154 $ 225,524 Loans are considered to be performing if they are in compliance with the original terms of the agreement which is consistent with the regulatory guideline of “pass.” Performing also includes loans considered to be “other loans especially mentioned” by regulatory guidelines and all residential mortgage loans guaranteed by agencies of the U.S. government that continue to accrue interest based on criteria of the guarantor's programs. Other loans especially mentioned are currently performing in compliance with the original terms of the agreement but may have a potential weakness that deserves management's close attention, consistent with regulatory guidelines. The risk grading process identified certain loans that have a well-defined weakness (e.g. inadequate debt service coverage or liquidity or marginal capitalization; repayment may depend on collateral or other risk mitigation) that may jeopardize liquidation of the debt and represent a greater risk due to deterioration in the financial condition of the borrower. This is consistent with the regulatory guideline for “substandard.” Because the borrowers are still performing in accordance with the original terms of the loan agreements, these loans were not placed in nonaccruing status. Nonaccruing loans represent loans for which full collection of principal and interest in accordance with the original terms of the loan agreements is uncertain. This is substantially the same criteria used to determine whether a loan is impaired and includes certain loans considered “substandard” and all loans considered “doubtful” by regulatory guidelines. The following table summarizes the Company’s loan portfolio at December 31, 2016 by the risk grade categories (in thousands): Internally Risk Graded Non-Graded Performing Pass Other Loans Especially Mentioned Accruing Substandard Nonaccrual Performing Nonaccrual Total Commercial: Energy $ 1,937,790 $ 119,583 $ 307,996 $ 132,499 — — $ 2,497,868 Services 3,052,002 10,960 37,855 8,173 — — 3,108,990 Wholesale/retail 1,535,463 16,886 13,062 11,407 — — 1,576,818 Manufacturing 468,314 26,532 15,198 4,931 — — 514,975 Healthcare 2,140,458 44,472 16,161 825 — — 2,201,916 Other commercial and industrial 433,789 5,309 — 21,060 30,041 58 490,257 Total commercial 9,567,816 223,742 390,272 178,895 30,041 58 10,390,824 Commercial real estate: Residential construction and land development 131,630 — 470 3,433 — — 135,533 Retail 756,418 4,745 399 326 — — 761,888 Office 798,462 — — 426 — — 798,888 Multifamily 898,800 — 4,434 38 — — 903,272 Industrial 871,673 — — 76 — — 871,749 Other commercial real estate 336,488 — 6 1,222 — — 337,716 Total commercial real estate 3,793,471 4,745 5,309 5,521 — — 3,809,046 Residential mortgage: Permanent mortgage 238,769 1,186 2,331 1,417 741,679 21,438 1,006,820 Permanent mortgages guaranteed by U.S. government agencies — — — — 187,541 11,846 199,387 Home equity — — — — 732,106 11,519 743,625 Total residential mortgage 238,769 1,186 2,331 1,417 1,661,326 44,803 1,949,832 Personal 743,451 — 1,054 97 95,163 193 839,958 Total $ 14,343,507 $ 229,673 $ 398,966 $ 185,930 $ 1,786,530 $ 45,054 $ 16,989,660 The following table summarizes the Company’s loan portfolio at December 31, 2015 by the risk grade categories (in thousands): Internally Risk Graded Non-Graded Performing Pass Other Loans Especially Mentioned Accruing Substandard Nonaccrual Performing Nonaccrual Total Commercial: Energy $ 2,580,694 $ 325,663 $ 129,782 61,189 $ — $ — $ 3,097,328 Services 2,763,929 3,296 6,761 10,290 — — 2,784,276 Wholesale/retail 1,394,596 18,184 6,365 2,919 — — 1,422,064 Manufacturing 534,966 19,560 1,872 331 — — 556,729 Healthcare 1,876,745 5,563 — 1,072 — — 1,883,380 Other commercial and industrial 477,551 5,479 — 496 25,101 127 508,754 Total commercial 9,628,481 377,745 144,780 76,297 25,101 127 10,252,531 Commercial real estate: Residential construction and land development 154,369 1,355 293 4,409 — — 160,426 Retail 788,708 6,046 426 1,319 — — 796,499 Office 636,210 291 555 651 — — 637,707 Multifamily 744,299 — 6,512 274 — — 751,085 Industrial 563,093 — — 76 — — 563,169 Other commercial real estate 347,864 — 11 2,272 — — 350,147 Total commercial real estate 3,234,543 7,692 7,797 9,001 — — 3,259,033 Residential mortgage: Permanent mortgage 192,367 89 1,932 2,313 721,964 26,671 945,336 Permanent mortgages guaranteed by U.S. government agencies — — — — 175,037 21,900 196,937 Home equity — — — — 724,264 10,356 734,620 Total residential mortgage 192,367 89 1,932 2,313 1,621,265 58,927 1,876,893 Personal 467,808 3 14 130 84,409 333 552,697 Total $ 13,523,199 $ 385,529 $ 154,523 87,741 $ 1,730,775 $ 59,387 $ 15,941,154 Impaired Loans Loans are considered to be impaired when it is probable that the Company will not be able to collect all amounts due according to the contractual terms of the loan agreement. This includes all nonaccruing loans, all loans modified in a troubled debt restructuring and all loans repurchased from GNMA pools. A summary of impaired loans follows (in thousands): As of December 31, 2016 Year Ended Recorded Investment December 31, 2016 Unpaid Principal Balance Total With No With Allowance Related Allowance Average Recorded Interest Income Recognized Commercial: Energy $ 146,897 $ 132,499 $ 121,418 $ 11,081 $ 762 $ 80,100 $ — Services 11,723 8,173 8,173 — — 9,232 — Wholesale/retail 17,669 11,407 11,407 — — 7,163 — Manufacturing 5,320 4,931 4,931 — — 2,631 — Healthcare 1,147 825 825 — — 949 — Other commercial and industrial 29,006 21,118 21,083 35 35 10,870 — Total commercial 211,762 178,953 167,837 11,116 797 110,945 — Commercial real estate: Residential construction and land development 4,951 3,433 3,433 — — 3,921 — Retail 530 326 326 — — 823 — Office 521 426 426 — — 539 — Multifamily 1,000 38 38 — — 156 — Industrial 76 76 76 — — 76 — Other commercial real estate 7,349 1,222 1,222 — — 1,747 — Total commercial real estate 14,427 5,521 5,521 — — 7,262 — Residential mortgage: Permanent mortgage 28,830 22,855 22,809 46 46 25,920 1,255 Permanent mortgage guaranteed by U.S. government agencies 1 205,564 199,387 199,387 — — 193,889 7,759 Home equity 12,611 11,519 11,519 — — 10,937 — Total residential mortgage 247,005 233,761 233,715 46 46 230,746 9,014 Personal 332 290 290 — — 377 — Total $ 473,526 $ 418,525 $ 407,363 $ 11,162 $ 843 $ 349,330 $ 9,014 1 All permanent mortgage loans guaranteed by U.S. government agencies are considered impaired as we do not expect full collection of contractual principal and interest. At December 31, 2016 , $12 million of these loans are nonaccruing and $188 million are accruing based on the guarantee by U.S. government agencies. Generally, no interest income is recognized on impaired loans until all principal balances, including amounts charged-off, have been recovered. As of December 31, 2015 Year Ended Recorded Investment December 31, 2015 Unpaid Principal Balance Total With No Allowance With Allowance Related Allowance Average Recorded Investment Interest Income Recognized Commercial: Energy $ 63,910 $ 61,189 $ 18,330 $ 42,859 $ 16,115 $ 31,303 $ — Services 13,449 10,290 9,657 633 148 7,746 — Wholesale/retail 8,582 2,919 2,907 12 9 3,534 — Manufacturing 665 331 331 — — 391 — Healthcare 1,352 1,072 931 141 35 1,226 — Other commercial and industrial 8,304 623 623 — — 777 — Total commercial 96,262 76,424 32,779 43,645 16,307 44,977 — Commercial real estate: Residential construction and land development 8,963 4,409 4,409 — — 4,854 — Retail 1,923 1,319 1,319 — — 2,622 — Office 937 651 651 — — 2,035 — Multifamily 1,192 274 274 — — 137 — Industrial 76 76 76 — — 38 — Other commercial real estate 8,363 2,272 2,113 159 18 4,092 — Total commercial real estate 21,454 9,001 8,842 159 18 13,778 — Residential mortgage: Permanent mortgage 37,273 28,984 28,868 116 68 31,914 1,242 Permanent mortgage guaranteed by U.S. government agencies 1 202,984 196,937 196,937 — — 196,827 7,814 Home equity 10,988 10,356 10,356 — — 9,960 — Total residential mortgage 251,245 236,277 236,161 116 68 238,701 9,056 Personal 489 463 463 — — 515 — Total $ 369,450 $ 322,165 $ 278,245 $ 43,920 $ 16,393 $ 297,971 $ 9,056 1 All permanent mortgage loans guaranteed by U.S. government agencies are considered impaired as we do not expect full collection of contractual principal and interest. At December 31, 2015 , $22 million of these loans are nonaccruing and $175 million are accruing based on the guarantee by U.S. government agencies. Troubled Debt Restructurings A summary of troubled debt restructurings ("TDRs") by accruing status as of December 31, 2016 is as follows (in thousands): As of December 31, 2016 Recorded Investment Performing in Accordance With Modified Terms Not Performing in Accordance With Modified Terms Specific Allowance Amounts Charged-Off During the Year Ended December 31, 2016 Nonaccruing TDRs: Commercial: Energy $ 16,893 $ 10,867 $ 6,026 $ — $ 4,401 Services 7,527 6,830 697 — — Wholesale/Retail 11,291 11,251 40 — — Manufacturing 224 224 — — — Healthcare 607 — 607 — — Other commercial and industrial 337 53 284 — — Total commercial 36,879 29,225 7,654 — 4,401 Commercial real estate: Residential construction and land development 690 97 593 — — Retail 326 326 — — — Office 143 143 — — — Multifamily — — — — — Industrial — — — — — Other commercial real estate 548 548 — — — Total commercial real estate 1,707 1,114 593 — — Residential mortgage: Permanent mortgage 14,876 10,175 4,701 46 28 Permanent mortgage guaranteed by U.S. government agencies 6,702 2,241 4,461 — — Home equity 5,346 4,458 888 — 230 Total residential mortgage 26,924 16,874 10,050 46 258 Personal 237 236 1 — 73 Total nonaccruing TDRs 65,747 47,449 18,298 46 4,732 Accruing TDRs: Residential mortgage: Permanent mortgages guaranteed by U.S. government agencies 81,370 27,289 54,081 — — Total residential mortgage 81,370 27,289 54,081 — — Total accruing TDRs 81,370 27,289 54,081 — — Total TDRs $ 147,117 $ 74,738 $ 72,379 $ 46 $ 4,732 A summary of troubled debt restructurings by accruing status as of December 31, 2015 is as follows (in thousands): As of December 31, 2015 Recorded Investment Performing in Accordance With Modified Terms Not Performing in Accordance With Modified Terms Specific Allowance Amounts Charged-off During the Year Ended December 31, 2015 Nonaccruing TDRs: Commercial: Energy $ 2,304 $ 2,304 $ — $ — $ 928 Services 9,027 8,210 817 148 — Wholesale/retail 2,758 2,706 52 9 — Manufacturing 282 282 — — — Healthcare 673 673 — — — Other commercial and industrial 621 89 532 — — Total commercial 15,665 14,264 1,401 157 928 Commercial real estate: Residential construction and land development 2,328 1,556 772 — — Retail 1,319 942 377 — — Office 165 165 — — — Multifamily — — — — — Industrial — — — — — Other commercial real estate 920 478 442 — — Total commercial real estate 4,732 3,141 1,591 — — Residential mortgage: Permanent mortgage 16,618 9,043 7,575 68 192 Permanent mortgage guaranteed by U.S. government agencies 11,136 139 10,997 — — Home equity 5,159 4,218 941 — 80 Total residential mortgage 32,913 13,400 19,513 68 272 Personal 324 297 27 — 11 Total nonaccuring TDRs 53,634 31,102 22,532 225 1,211 Accruing TDRs: Residential mortgage: Permanent mortgages guaranteed by U.S. government agencies 74,050 23,029 51,021 — — Total residential mortgage 74,050 23,029 51,021 — — Total accruing TDRs 74,050 23,029 51,021 — — Total TDRs $ 127,684 $ 54,131 $ 73,553 $ 225 $ 1,211 Troubled debt restructurings generally consist of interest rate concessions, payment stream concessions or a combination of concessions to distressed borrowers. The following table details the recorded balance of loans at December 31, 2016 by class that were restructured during the year ended December 31, 2016 by primary type of concession (in thousands): Year Ended December 31, 2016 Accruing Nonaccrual Total Payment Stream Combination & Other Total Interest Rate Payment Stream Combination & Other Total Commercial: Energy $ — $ — $ — $ — $ — $ 16,892 $ 16,892 $ 16,892 Services — — — — — — — — Wholesale/retail — — — — — 9,103 9,103 9,103 Manufacturing — — — — — — — — Healthcare — — — — — — — — Other commercial and industrial — — — — — — — — Total commercial — — — — — 25,995 25,995 25,995 Commercial real estate: Residential construction and land development — — — — — — — — Retail — — — — — — — — Office — — — — — — — — Multifamily — — — — — — — — Industrial — — — — — — — — Other commercial real estate — — — — — — — — Total commercial real estate — — — — — — — — Residential mortgage: Permanent mortgage — — — — 1,036 328 1,364 1,364 Permanent mortgage guaranteed by U.S. government agencies 11,879 10,042 21,921 — — 979 979 22,900 Home equity — — — — 46 2,077 2,123 2,123 Total residential mortgage 11,879 10,042 21,921 — 1,082 3,384 4,466 26,387 Personal — — — — — 77 77 77 Total $ 11,879 $ 10,042 $ 21,921 $ — $ 1,082 $ 29,456 $ 30,538 $ 52,459 The following table details the recorded balance of loans by class that were restructured during the year ended December 31, 2015 by primary type of concession (in thousands): Year Ended December 31, 2015 Accruing Nonaccrual Total Payment St

Premises and Equipment

Premises and Equipment	12 Months Ended
	Dec. 31, 2016
Property, Plant and Equipment [Abstract]
Premises and Equipment Disclosure [Text Block]	Premises and Equipment Premises and equipment at December 31 are summarized as follows (in thousands): December 31, 2016 2015 Land $ 70,552 $ 72,612 Buildings and improvements 250,311 225,181 Software 158,155 142,476 Furniture and equipment 217,399 194,715 Construction in progress 36,743 39,886 Premises and equipment 733,160 674,870 Less accumulated depreciation 407,311 368,380 Premises and equipment, net of accumulated depreciation $ 325,849 $ 306,490 Depreciation expense of premises and equipment was $40 million , $34 million and $33 million for the years ended December 31, 2016 , 2015 and 2014 , respectively.

Goodwill and Intangible Assets

Goodwill and Intangible Assets	12 Months Ended
	Dec. 31, 2016
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Intangible Assets [Text Block]	Goodwill and Intangible Assets On May 4, 2015, the Company acquired a majority voting interest in Heartland Food Products, LLC, a Kansas-based food product and restaurant equipment company pursuant to merchant banking regulations and restrictions. The cash purchase price for this acquisition was $18 million . The purchase price allocation included $11 million of identifiable intangible assets and $2.7 million of goodwill. On January 12, 2016, the Company acquired E-Spectrum Advisors, a boutique energy investment banking firm based in Dallas that offers a broad range of oil and natural gas property sales and strategic advisory services. On February 29, 2016, the Company acquired Weaver and Tidwell Financial Advisors LTD d/b/a Weaver Wealth Management, a registered investment advisor. The acquisition included hiring Weaver Wealth Management’s team and transitioning its wealth management clients to The Milestone Group, a wholly owned subsidiary of BOK Financial. The acquisition increased BOK Financial’s assets under management and administration by approximately $340 million . The combined cash purchase price for these two acquisitions in 2016 totaled $7.7 million , including $5.3 million of identifiable intangible assets and $3.3 million of goodwill. On December 1, 2016 , the Company acquired MBT Bancshares, Inc. ("MBT"), parent company of Missouri Bank and Trust of Kansas City (“Mobank”). Mobank operates four banking branches in the Kansas City, Missouri area. BOK Financial paid $102.5 million in an all-cash deal for all outstanding shares of MBT stock. MBT was merged into BOK Financial and Mobank became a wholly owned subsidiary of BOK Financial on December 1, 2016. On February 17, 2017, Mobank was merged with the Bank of Kansas City banking division of BOKF, NA. All branches in the Kansas City market will operate under the Mobank name. A summary of the preliminary purchase price allocation and resulting goodwill follows (in thousands): Cash and cash equivalents $ 166,215 Securities 14,431 Loans 1 444,482 Premises and equipments, net 8,035 Intangible assets – Core deposit premium 6,510 Other assets 3,599 Total assets acquired 643,272 Deposits 598,735 Other borrowings 7,217 Other liabilities 980 Total liabilities assumed 606,932 Net assets acquired 36,340 Less: purchase price 102,500 Goodwill $ 66,160 1 Loans are presented net of participations sold to BOKF NA. The pro-forma impact of all acquisition transactions for periods prior to the acquisition dates was not material to the Company's consolidated financial statements. The following table presents the original cost and accumulated amortization of intangible assets (in thousands): Dec. 31, 2016 2015 Core deposit premiums $ 35,879 $ 29,369 Less accumulated amortization 29,369 29,101 Net core deposit premiums 6,510 268 Other identifiable intangible assets 60,951 55,509 Less accumulated amortization 20,530 11,868 Net other identifiable intangible assets 40,421 43,641 Total intangible assets, net $ 46,931 $ 43,909 Expected amortization expense for intangible assets that will continue to be amortized (in thousands): Core Deposit Premiums Other Identifiable Intangible Assets Total 2017 $ 808 $ 4,565 $ 5,373 2018 732 3,908 4,640 2019 716 3,556 4,272 2020 697 3,420 4,117 2021 675 3,063 3,738 Thereafter 2,882 21,909 24,791 $ 6,510 $ 40,421 $ 46,931 The changes in the carrying value of goodwill by operating segment are as follows (in thousands): Commercial Banking Consumer Banking Wealth Management Funds Management and Other Total Balance, December 31, 2014 Goodwill $ 269,363 $ 39,251 $ 69,394 $ — $ 378,008 Accumulated impairment losses — (228 ) — — (228 ) 269,363 39,023 69,394 — 377,780 Goodwill acquired during 2015 7,681 — — — 7,681 Balance, December 31, 2015 Goodwill 277,044 39,251 69,394 — 385,689 Accumulated impairment losses — (228 ) — — (228 ) 277,044 39,023 69,394 — 385,461 Goodwill acquired during 2016 1,210 — 2,126 66,160 69,496 Adjustment 1 (6,058 ) — — — (6,058 ) Balance, December 31, 2016 Goodwill 272,196 39,251 71,520 66,160 449,127 Accumulated impairment losses — (228 ) — — (228 ) $ 272,196 $ 39,023 $ 71,520 $ 66,160 $ 448,899 1 Completion of an external audit of Heartland Food Products resulted in a reallocation of the purchase price between net assets acquired, intangible assets and goodwill during 2016. Goodwill related to the Mobank acquisition was not yet allocated to the operating segments as of December 31, 2016 and accordingly is included in Funds Management and Other above. All of the goodwill related to the Mobank acquisition is tax deductible. The annual goodwill evaluations for 2016 and 2015 did not indicate impairment for any reporting unit. Economic conditions did not indicate that impairment existed for any identifiable intangible assets and therefore no impairment evaluation was performed.

Mortgage Banking Activities Mor

Mortgage Banking Activities Mortgage Banking Activities (Notes)	12 Months Ended
	Dec. 31, 2016
Mortgage Banking [Abstract]
Mortgage Banking Activities [Text Block]	Mortgage Banking Activities Residential Mortgage Loan Production The Company originates, markets and services conventional and government-sponsored residential mortgage loans. Generally, conforming fixed rate residential mortgage loans are held for sale in the secondary market and non-conforming and adjustable-rate residential mortgage loans are held for investment. The volume of mortgage loans originated for sale and secondary market prices are the primary drivers of originating and marketing revenue. Residential mortgage loan commitments are generally outstanding for 60 to 90 days, which represents the typical period from commitment to originate a residential mortgage loan to when the closed loan is sold to an investor. Residential mortgage loan commitments are subject to both credit and interest rate risk. Credit risk is managed through underwriting policies and procedures, including collateral requirements, which are generally accepted by the secondary loan markets. Exposure to interest rate fluctuations is partially managed through forward sales of residential mortgage-backed securities and forward sales contracts. These latter contracts set the price for loans that will be delivered in the next 60 to 90 days. The unpaid principal balance of residential mortgage loans held for sale, notional amounts of derivative contracts related to residential mortgage loan commitments and forward contract sales and their related fair values included in Mortgage loans held for sale on the Consolidated Balance Sheets were (in thousands): December 31, 2016 December 31, 2015 Unpaid Principal Balance/ Notional Fair Value Unpaid Principal Balance/ Notional Fair Value Residential mortgage loans held for sale $ 286,414 $ 286,971 $ 293,637 $ 299,505 Residential mortgage loan commitments 318,359 9,733 601,147 8,134 Forward sales contracts 569,543 5,193 884,710 800 $ 301,897 $ 308,439 No residential mortgage loans held for sale were 90 days or more past due or considered impaired as of December 31, 2016 or December 31, 2015 . No credit losses were recognized on residential mortgage loans held for sale for the years ended December 31, 2016 , 2015 and 2014 . Mortgage banking revenue was as follows (in thousands): Year Ended 2016 2015 2014 Production revenue: Net realized gains on sales of mortgage loans $ 68,947 $ 67,407 $ 56,696 Net change in unrealized gain on mortgage loans held for sale (5,311 ) (784 ) 5,357 Net change in the fair value of mortgage loan commitments 1,599 (1,837 ) 7,315 Net change in the fair value of forward sales contracts 4,393 4,801 (8,307 ) Total production revenue 69,628 69,587 61,061 Servicing revenue 64,286 56,415 48,032 Total mortgage banking revenue $ 133,914 $ 126,002 $ 109,093 Mortgage production revenue includes gain (loss) on residential mortgage loans held for sale and changes in the fair value of derivative contracts not designated as hedging instruments related to residential mortgage loan commitments and forward sales contracts. Servicing revenue includes servicing fee income and late charges on loans serviced for others. Residential Mortgage Servicing The Company generally retains the right to service residential mortgage loans sold and may purchase mortgage servicing rights. The unpaid principal balance of loans serviced for others is the primary driver of servicing revenue. The following represents a summary of mortgage servicing rights (Dollars in thousands): December 31, 2016 2015 2014 Number of residential mortgage loans serviced for others 139,340 131,859 117,483 Outstanding principal balance of residential mortgage loans serviced for others $ 21,997,568 $ 19,678,226 $ 16,162,887 Weighted average interest rate 3.97 % 4.12 % 4.29 % Remaining contractual term (in months) 301 300 296 Activity in capitalized mortgage servicing rights during the three years ended December 31, 2016 is as follows (in thousands): Purchased Originated Total Balance, December 31, 2013 $ 15,935 $ 137,398 $ 153,333 Additions, net — 54,413 54,413 Change in fair value due to loan runoff (2,357 ) (16,968 ) (19,325 ) Change in fair value due to market changes (2,464 ) (13,981 ) (16,445 ) Balance, December 31, 2014 11,114 160,862 171,976 Additions, net — 79,546 79,546 Change in fair value due to loan runoff (2,645 ) (25,419 ) (28,064 ) Change in fair value due to market changes 1,442 (6,295 ) (4,853 ) Balance, December 31, 2015 9,911 208,694 218,605 Additions, net — 71,405 71,405 Change in fair value due to loan runoff (2,844 ) (37,900 ) (40,744 ) Change in fair value due to market changes 1,842 (4,035 ) (2,193 ) Balance, December 31, 2016 $ 8,909 $ 238,164 $ 247,073 Changes in the fair value of mortgage servicing rights due to market changes are included in Other operating revenue in the Consolidated Statements of Earnings. Changes in fair value due to loan runoff are included in Mortgage banking costs. There is no active market for trading in mortgage servicing rights after origination. Fair value is determined by discounting the projected net cash flows. Significant assumptions used to determine fair value considered to be significant unobservable inputs were as follows: December 31, 2016 2015 Discount rate – risk-free rate plus a market premium 10.08% 10.11% Prepayment rate - based upon loan interest rate, original term and loan type 8.98%-16.91% 7.41% - 23.88% Loan servicing costs – annually per loan based upon loan type: Performing loans $63 - $120 $63 - $105 Delinquent loans $150 - $500 $150 - $500 Loans in foreclosure $650 - $4,250 $650 - $4,250 Primary/secondary mortgage rate spread 105 bps 130 bps Escrow earnings rate – indexed to rates paid on deposit accounts with comparable average life 1.98% 1.73% Changes in primary residential mortgage interest rates directly affect the prepayment speeds used in valuing our mortgage servicing rights. A separate third party model is used to estimate prepayment speeds based on interest rates, housing turnover rates, estimated loan curtailment, anticipated defaults and other relevant factors. The prepayment model is updated periodically for changes in market conditions and adjusted to better correlate with actual performance of BOK Financial’s servicing portfolio. The interest rate sensitivity of our mortgage servicing rights is modeled over a range of +/- 50 basis points. At December 31, 2016 , a 50 basis point increase in mortgage interest rates is expected to increase the fair value of our mortgage servicing rights by $25 million . A 50 basis point decrease in mortgage interest rates is expected to decrease the fair value of our mortgage servicing rights by $29 million . In the model, changes in the value of servicing rights due to changes in interest rates assume stable relationships between residential mortgage rates and prepayment speeds. Changes in market conditions can cause variations from these assumptions. These factors and others may cause changes in the value of our mortgage servicing rights to differ from our expectations. The aging status of our mortgage loans serviced for others by investor at December 31, 2016 follows (in thousands): Past Due Current 30 to 59 Days 60 to 89 Days 90 Days or More Total FHLMC $ 7,950,818 $ 52,434 $ 9,812 $ 25,670 $ 8,038,734 FNMA 6,922,833 44,532 11,233 21,486 7,000,084 GNMA 6,304,914 181,669 56,534 22,471 6,565,588 Other 390,109 763 351 1,939 393,162 Total $ 21,568,674 $ 279,398 $ 77,930 $ 71,566 $ 21,997,568 The Company has off-balance sheet credit risk related to first lien, fixed-rate residential mortgage loans sold to U.S. government agencies with recourse prior to 2008 under various community development programs. The Company no longer sells residential mortgage loans with recourse other than obligations under standard representations and warranties. The recourse obligation relates to loan performance for the life of the loan. The principal balance of residential mortgage loans sold subject to recourse obligations totaled $139 million at December 31, 2016 and $155 million at December 31, 2015 . A separate accrual for these off-balance sheet commitments is included in Other liabilities in the Consolidated Balance Sheets. The provision for credit losses on loans sold with recourse is included in Mortgage banking costs in the Consolidated Statements of Earnings. The activity in the accrual for losses on loans sold with recourse included in Other liabilities in the Consolidated Balance Sheets is summarized as follows (in thousands): Year Ended 2016 2015 2014 Beginning balance $ 4,649 $ 7,299 $ 9,562 Provision for recourse losses 725 (982 ) 354 Loans charged off, net (1,358 ) (1,668 ) (2,617 ) Ending balance $ 4,016 $ 4,649 $ 7,299 The Company also has off-balance sheet obligations to repurchase or provide indemnification for residential mortgage loans sold to government sponsored entities due to standard representations and warranties made under contractual agreements. The Company has established an accrual for credit losses related to potential loan repurchases under representations and warranties and related servicing expenses that is included in Other liabilities in the Consolidated Balance Sheets and in Mortgage banking costs in the Consolidated Statements of Earnings. In 2016 , the Company repurchased 18 loans from the agencies for $3.9 million and paid indemnification for 7 loans. Losses on both repurchases and indemnifications were insignificant. A summary of unresolved deficiency requests from the agencies follows (in thousands, except for number of unresolved deficiency requests): December 31, 2016 2015 Number of unresolved deficiency requests 233 198 Aggregate outstanding principal balance subject to unresolved deficiency requests $ 17,382 $ 15,624 Unpaid principal balance subject to indemnification by the Company 5,803 4,365 The activity in the accruals for mortgage losses related to repurchases is summarized as follows (in thousands). December 31, 2016 2015 Beginning balance $ 3,359 $ 3,220 Provision for losses 27 353 Charge-offs, net (598 ) (214 ) Ending balance $ 2,788 $ 3,359

Deposits

Deposits	12 Months Ended
	Dec. 31, 2016
Deposits [Abstract]
Deposits [Text Block]	Deposits Interest expense on deposits is summarized as follows (in thousands): Year Ended December 31, 2016 2015 2014 Transaction deposits $ 13,906 $ 8,821 $ 9,757 Savings 386 383 401 Time: Certificates of deposits under $100,000 8,776 11,894 14,278 Certificates of deposits $100,000 and over 10,123 10,643 11,878 Other time deposits 7,303 12,429 14,369 Total time 26,202 34,966 40,525 Total $ 40,494 $ 44,170 $ 50,683 The aggregate amounts of time deposits in denominations of $250,000 or more at December 31, 2016 and 2015 were $ 866 million and $ 905 million , respectively. Time deposit maturities are as follows: 2017 – $ 1.3 billion , 2018 – $ 340 million , 2019 – $ 71 million , 2020 – $ 94 million , 2021 – $ 114 million and $ 342 million thereafter. At December 31, 2016 and 2015 , the Company had $417 million and $358 million , respectively, in fixed rate, brokered certificates of deposits. The weighted-average interest rate paid on these certificates was 1.33% in 2016 and 1.48% in 2015 . The aggregate amount of overdrawn customer transaction deposits that have been reclassified as loan balances was $ 9.7 million at December 31, 2016 and $ 5.3 million at December 31, 2015 .

Other Borrowings

Other Borrowings	12 Months Ended
	Dec. 31, 2016
Debt Disclosure [Abstract]
Other borrowings [Text Block]	Other Borrowings Information relating to other borrowings is summarized as follows (dollars in thousands): As of Year Ended December 31, 2016 December 31, 2016 Balance Rate Average Balance Rate Maximum Parent company and other non-bank subsidiaries: Trust preferred debt $ 7,217 3.28 % $ 611 3.27 % $ 7,217 Other 1,092 8.27 % 2,073 16.11 % 3,157 Total other borrowings 8,309 2,684 13.19 % Subordinated debentures 144,640 5.60 % 74,428 5.59 % $ 145,393 Total parent company and other non-bank subsidiaries 152,949 77,112 5.86 % BOKF, NA: Funds purchased 57,929 0.38 % 78,222 0.24 % 567,103 Repurchase agreements 668,661 0.02 % 589,145 0.04 % 668,661 Other borrowings: Federal Home Loan Bank advances 4,800,000 0.72 % 5,985,656 0.55 % 6,500,000 GNMA repurchase liability 22,471 4.26 % 15,637 4.74 % 22,471 Other 15,292 2.66 % 15,670 2.41 % 15,797 Total other borrowings 4,837,763 6,016,963 0.57 % Subordinated debentures — — % 140,414 1.35 % 226,434 Total BOKF, NA 5,564,353 6,824,744 0.54 % Total other borrowed funds $ 5,717,302 $ 6,901,856 0.60 % As of Year Ended December 31, 2015 December 31, 2015 Balance Rate Average Balance Rate Maximum Parent company and other non-bank subsidiaries: Trust preferred debt $ — — % $ — — % $ — Other — — % — — % — Total other borrowings — — — % Subordinated debentures — — % — — % — Total parent company and other non-bank subsidiaries — — — % BOKF, NA: Funds purchased 491,192 0.15 % 73,219 0.09 % 491,192 Repurchase agreements 722,444 0.02 % 623,921 0.04 % 1,008,144 Other borrowings: Federal Home Loan Bank advances 4,800,000 0.48 % 4,921,739 0.28 % 5,000,000 GNMA repurchase liability 19,478 4.75 % 16,668 4.95 % 19,478 Other 18,402 2.70 % 18,768 2.35 % 26,058 Total other borrowings 4,837,880 4,957,175 0.33 % Subordinated debentures 226,350 1.05 % 226,332 1.84 % 348,076 Total BOKF, NA 6,277,866 5,880,647 0.36 % Total other borrowed funds $ 6,277,866 $ 5,880,647 0.36 % As of Year Ended December 31, 2014 December 31, 2014 Balance Rate Average Balance Rate Maximum Parent company and other non-bank subsidiaries: Trust preferred debt $ — — % $ — — % $ — Other — — % — — % — Total other borrowings — — — % Subordinated debentures — — % — — % — Total parent company and other non-bank subsidiaries — — — % BOKF, NA: Funds purchased 57,031 0.05 % 494,220 0.07 % 1,548,676 Repurchase agreements 1,187,489 0.04 % 928,767 0.06 % 1,187,489 Other borrowings: Federal Home Loan Bank advances 2,103,400 0.25 % 1,894,966 0.24 % 3,453,400 GNMA repurchase liability 14,298 5.05 % 17,343 5.20 % 24,980 Other 16,076 2.73 % 16,433 2.32 % 16,582 Total other borrowings 2,133,774 1,928,742 0.35 % Subordinated debentures 347,983 2.35 % 347,892 2.50 % 347,983 Total BOKF, NA 3,726,277 3,699,621 0.43 % Total other borrowed funds $ 3,726,277 $ 3,699,621 0.43 % Aggregate annual principal repayments at December 31, 2016 are as follows (in thousands): Parent Company and Other Non-bank Subsidiaries BOKF, NA 2017 $ — $ 5,549,587 2018 — 711 2019 — 956 2020 — 961 2021 — 965 Thereafter 152,949 11,173 Total $ 152,949 $ 5,564,353 Funds purchased are unsecured and generally mature within one to ninety days from the transaction date. Securities repurchase agreements are recorded as secured borrowings that generally mature within ninety days and are secured by certain available for sale securities. There was no outstanding accrued interest payable related to repurchase agreements at December 31, 2016 or December 31, 2015 . Additional information relating to securities sold under agreements to repurchase and related liabilities at December 31, 2016 and 2015 is as follows (dollars in thousands): December 31, 2016 Amortized Fair Repurchase Average Security Sold/Maturity Cost Value Liability 1 Rate U.S. government agency mortgage-backed securities: Overnight 1 $ 655,529 $ 655,851 $ 668,661 0.02 % Long-term — — — — % Total Agency Securities $ 655,529 $ 655,851 $ 668,661 0.02 % December 31, 2015 Amortized Fair Repurchase Average Security Sold/Maturity Cost Value Liability 1 Rate U.S. government agency mortgage-backed securities: Overnight 1 $ 685,458 $ 688,485 $ 722,444 0.02 % Long-term — — — — % Total Agency Securities $ 685,458 $ 688,485 $ 722,444 0.02 % 1 BOK Financial maintains control over the securities underlying overnight repurchase agreements and generally transfers control over securities underlying longer-term dealer repurchase agreements to the respective counterparty. Borrowings from the Federal Home Loan Banks are used for funding purposes. In accordance with policies of the Federal Home Loan Banks, BOK Financial has granted a blanket pledge of eligible assets (generally unencumbered U.S. Treasury and residential mortgage-backed securities, 1-4 family loans and multifamily loans) as collateral for these advances. The Federal Home Loan Banks have issued letters of credit totaling $242 million to secure BOK Financial’s obligations to depositors of public funds. The unused credit available to BOK Financial at December 31, 2016 pursuant to the Federal Home Loan Bank’s collateral policies is $1.3 billion . In 2016, BOK Financial issued $150 million of subordinated debt that will mature on June 30, 2056 . Interest on this debt bears an interest rate of 5.375% , payable quarterly. On June 30, 2021 , BOK Financial will have the option to redeem the debt at the principal amount plus accrued interest, subject to regulatory approval. In conjunction with the acquisition of MBT, BOK Financial assumed $7.2 million of variable rate subordinated trust preferred. This trust preferred debt is callable prior to maturity on September 17, 2033 and December 15, 2036 , respectively, subject to regulatory approval. Interest is payable quarterly at three-month LIBOR plus 2.95% on $3.1 million and three-month LIBOR plus 1.82% on $4.1 million . BOK Financial Securities, Inc. may borrow funds from Pershing, LLC ("Pershing"), a clearing broker/dealer and a wholly owned subsidiary of Bank of New York Mellon, for the purposes of financing securities purchases or to facilitate funding of investment banking activities, on terms to be negotiated at the time of the borrowing. BOK Financial Securities, Inc. had no borrowings from Pershing outstanding at December 31, 2016 or December 31, 2015 . In 2007, BOKF, NA issued $250 million of subordinated debt due May 15, 2017 . Interest on this debt was based upon a fixed rate of 5.75% through May 14, 2012 and is based on a floating rate of three-month LIBOR plus 0.69% thereafter . The proceeds of this debt were used to fund the Worth National Bank and First United Bank acquisitions and to fund continued asset growth. The outstanding balance of this subordinated debt was $226 million at December 31, 2015 . The remaining outstanding balance was called during 2016. The Company has a liability related to the repurchase of certain delinquent residential mortgage loans previously sold into GNMA mortgage pools. Interest is payable at rates contractually due to investors.

Federal and State Income Taxes

Federal and State Income Taxes	12 Months Ended
	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Federal and State Income Taxes [Text Block]	Federal and State Income Taxes Deferred income taxes reflect the net tax effects of temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes. Significant components of deferred tax assets and liabilities are as follows (in thousands): December 31, 2016 2015 Deferred tax assets: Available for sale securities mark to market $ 5,779 $ — Share-based compensation 9,360 10,522 Credit loss allowances 99,191 88,906 Valuation adjustments 12,222 6,957 Deferred compensation 30,262 25,950 Unearned fees 11,877 11,124 Other 42,541 34,169 Total deferred tax assets 211,232 177,628 Deferred tax liabilities: Available for sale securities mark to market — 14,828 Depreciation 25,877 22,080 Mortgage servicing rights 92,748 77,900 Lease financing 17,923 22,301 Other 45,363 41,904 Total deferred tax liabilities 181,911 179,013 Net deferred tax assets (liabilities) $ 29,321 $ (1,385 ) The Company determined that no valuation allowance was necessary on deferred tax assets as of December 31, 2016 and 2015 . The significant components of the provision for income taxes attributable to continuing operations for BOK Financial are shown below (in thousands): Year Ended December 31, 2016 2015 2014 Current income tax expense: Federal $ 107,379 $ 117,566 $ 95,289 State 11,028 12,397 9,392 Total current income tax expense 118,407 129,963 104,681 Deferred income tax expense: Federal (11,340 ) 8,397 36,521 State (690 ) 1,024 2,949 Total deferred income tax expense (12,030 ) 9,421 39,470 Total income tax expense $ 106,377 $ 139,384 $ 144,151 The reconciliations of income attributable to continuing operations at the U.S. federal statutory tax rate to income tax expense are as follows (in thousands): Year Ended December 31, 2016 2015 2014 Amount: Federal statutory tax $ 118,530 $ 151,075 $ 153,870 Tax exempt revenue (10,544 ) (9,553 ) (8,446 ) Effect of state income taxes, net of federal benefit 6,478 9,082 9,054 Utilization of tax credits: Low-income housing tax credits, net of amortization (4,171 ) (3,874 ) (2,953 ) Other tax credits (2,085 ) (2,085 ) (2,109 ) Bank-owned life insurance (2,911 ) (3,264 ) (3,183 ) Other, net 1,080 (1,997 ) (2,082 ) Total income tax expense $ 106,377 $ 139,384 $ 144,151 Year Ended December 31, 2016 2015 2014 Percent of pretax income: Federal statutory tax 35.0 % 35.0 % 35.0 % Tax exempt revenue (3.1 ) (2.2 ) (1.9 ) Effect of state income taxes, net of federal benefit 1.9 2.1 2.1 Utilization of tax credits: Low-income housing tax credits, net of amortization (1.2 ) (0.9 ) (0.7 ) Other tax credits (0.6 ) (0.5 ) (0.5 ) Bank-owned life insurance (0.9 ) (0.7 ) (0.7 ) Other, net 0.3 (0.5 ) (0.5 ) Total 31.4 % 32.3 % 32.8 % A reconciliation of the beginning and ending amount of unrecognized tax benefits is as follows (in thousands): 2016 2015 2014 Balance as of January 1 $ 13,232 $ 13,374 $ 12,058 Additions for tax for current year positions 5,640 2,226 3,813 Settlements during the period — — — Lapses of applicable statute of limitations (3,031 ) (2,368 ) (2,497 ) Balance as of December 31 $ 15,841 $ 13,232 $ 13,374 Of the above unrecognized tax benefits, $10.3 million , if recognized, would have affected the effective tax rate. BOK Financial recognizes interest and penalties accrued related to unrecognized tax benefits in income tax expense. The Company recognized $1.0 million for 2016 , $1.0 million for 2015 and $1.5 million for 2014 in interest and penalties. The Company had approximately $3.5 million and $3.3 million accrued for the payment of interest and penalties at December 31, 2016 and 2015 , respectively. Federal statutes remain open for federal tax returns filed in the previous three reporting periods. Various state income tax statutes remain open for the previous three to six reporting periods.

Employee Benefits

Employee Benefits	12 Months Ended
	Dec. 31, 2016
Compensation and Retirement Disclosure [Abstract]
Employee Benefits [Text Block]	Employee Benefits BOK Financial sponsors a defined benefit cash balance Pension Plan for all employees who satisfy certain age and service requirements. Pension Plan benefits were curtailed as of April 1, 2006. No participants may be added to the plan and no additional service benefits will be accrued. During 2016 and 2015, interest accrued on employees' account balances at a variable rate tied to the five-year trailing average of five-year U.S. Treasury securities plus 1.5% . The rate has a floor of 3.0% and a ceiling of 5.0% . The 2016 quarterly variable rates remained at 3.00% . The following table presents information regarding this plan (in thousands): December 31, 2016 2015 Change in projected benefit obligation: Projected benefit obligation at beginning of year $ 38,797 $ 45,224 Interest cost 1,309 1,487 Actuarial loss (gain) (55 ) (2,702 ) Benefits paid (5,087 ) (5,212 ) Projected benefit obligation at end of year 1,2 $ 34,964 $ 38,797 Change in plan assets: Plan assets at fair value at beginning of year $ 44,190 $ 49,443 Actual return on plan assets 2,666 (41 ) Benefits paid (5,087 ) (5,212 ) Plan assets at fair value at end of year $ 41,769 $ 44,190 Funded status of the plan $ 6,805 $ 5,393 Components of net periodic benefit costs: Interest cost $ 1,309 $ 1,487 Expected return on plan assets (2,167 ) (2,706 ) Other (741 ) 1,849 Net benefit cost $ (1,599 ) $ 630 1 Projected benefit obligation equals accumulated benefit obligation. 2 Projected benefit obligation is based on January 1 measurement date. Weighted-average assumptions as of December 31: 2016 2015 Discount rate 3.43 % 3.54 % Expected return on plan assets 5.00 % 5.00 % As of December 31, 2016 , expected future benefit payments related to the Pension Plan were as follows (in thousands): 2017 $ 2,706 2018 3,072 2019 3,402 2020 3,090 2021 2,934 Thereafter 28,044 Total estimated future benefit payments $ 43,248 Assets of the Pension Plan consist primarily of shares in the Cavanal Hill Active Core Fund. The stated objective of this fund is to provide an attractive total return with a well-balanced mix of equities and bonds. The typical portfolio mix is approximately 60% equities and 40% bonds. The net asset value of shares in the Cavanal Hill Funds is reported daily based on market quotations for the Fund’s securities. Management considers the Fund's recent and long-term performance as indicators when setting the expected return on plan assets. As of December 31, 2016 , the expected return on plan assets for 2017 is 5.00% . The maximum tax deductible Pension Plan contribution for 2016 was $12 million . No minimum contribution was required for 2016 , 2015 or 2014 . Employee contributions to the Thrift Plan are eligible for Company matching equal to 6% of base compensation, as defined in the plan. The Company-provided matching contribution rates range from 50% for employees with less than 4 years of service to 200% for employees with 15 or more years of service. Additionally, a maximum Company-provided, non-elective annual contribution of up to $750 per participant is provided for employees whose annual base compensation is less than $40,000 . Total non-elective contributions were $530 thousand for 2016 , $605 thousand for 2015 and $662 thousand for 2014 . Participants may direct investments in their accounts to a variety of options, including a BOK Financial common stock fund and Cavanal Hill funds. Employer contributions, which are invested in accordance with the participant’s investment options, vest over five years. Thrift Plan expenses were $22.4 million for 2016 , $20.6 million for 2015 and $18.6 million for 2014 . BOK Financial offers numerous incentive compensation plans that are aligned with the Company’s growth strategy. Compensation awarded under these plans may be based on defined formulas, other performance criteria or discretionary. Incentive compensation is designed to motivate and reinforce sales and customer service behavior in all markets. Earnings were charged $128.1 million in 2016 , $114.3 million in 2015 , and $111.7 million in 2014 for cash incentive compensation.

Share-Based Compensation Plans

Share-Based Compensation Plans	12 Months Ended
	Dec. 31, 2016
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Share-Based Compensation Plans [Text Block]	Share-Based Compensation Plans The shareholders and Board of Directors of BOK Financial have approved various share-based compensation plans. An independent compensation committee of the Board of Directors determines the number of awards granted to the Chief Executive Officer and other senior executives. Share-based compensation is granted to other officers and employees as determined by the Chief Executive Officer. The following table presents stock options outstanding during 2016 , 2015 and 2014 under these plans (in thousands, except for per share data): Number Weighted- Average Exercise Price Aggregate Intrinsic Value Options outstanding at December 31, 2013 1,135,105 $ 49.09 $ 19,564 Options awarded — — Options exercised (323,004 ) 49.17 Options forfeited (15,509 ) 45.71 Options expired (2,701 ) 47.98 Options outstanding at December 31, 2014 793,891 49.05 8,725 Options awarded — — Options exercised (286,678 ) 47.86 Options forfeited (22,304 ) 48.90 Options expired (4,874 ) 51.32 Options outstanding at December 31, 2015 480,035 49.75 4,821 Options awarded — — Options exercised (249,404 ) 47.60 Options forfeited (4,098 ) 55.44 Options expired (8,009 ) 53.43 Options outstanding at December 31, 2016 218,524 $ 51.95 $ 6,793 Options vested at: December 31, 2014 347,633 $ 48.85 $ 3,889 December 31, 2015 243,395 48.17 2,829 December 31, 2016 93,117 46.22 3,429 The following table summarizes information concerning currently outstanding and vested stock options: Options Outstanding Options Vested Weighted Weighted Average Weighted Weighted Average Remaining Average Average Remaining Exercise Number Contractual Exercise Number Exercise Contractual Prices Outstanding Life (years) Price Vested Price Life (years) $36.65 36,722 1.45 $36.65 36,722 $36.65 1.45 48.30 14,208 2.32 48.30 6,906 48.30 1.57 48.46 21,138 0.81 48.46 21,138 48.46 0.81 54.33 3,628 0.03 54.33 3,628 54.33 0.03 55.74 51,570 4.28 55.74 5,008 55.74 2.03 55.94 48,800 3.08 55.94 12,260 55.94 1.72 58.76 42,458 3.62 58.76 7,455 58.76 1.70 The aggregate intrinsic value of options exercised was $ 6.2 million for 2016 , $ 5.1 million for 2015 and $ 5.5 million for 2014 . No options were granted in 2016, 2015 or 2014. Compensation expense recognized on stock options totaled $ 254 thousand for 2016 , $ 362 thousand for 2015 and $ 826 thousand for 2014 . Compensation cost of stock options granted that may be recognized as compensation expense in future years totaled $ 229 thousand at December 31, 2016 . The following represents a summary of the non-vested stock awards as of December 31, 2016 (in thousands): Shares Weighted Average Grant Date Fair Value Non-vested at January 1, 2014 647,989 Granted 206,621 $64.96 Vested (140,820 ) $44.56 Forfeited (25,179 ) $56.26 Non-vested at December 31, 2014 688,611 Granted 312,755 $57.66 Vested (114,045 ) $50.15 Forfeited (96,212 ) $58.33 Non-vested at December 31, 2015 791,109 Granted 256,670 $55.35 Vested (213,941 ) $55.87 Forfeited (47,132 ) $57.86 Non-vested at December 31, 2016 786,706 Compensation expense recognized on non-vested shares totaled $10.2 million for 2016 , $12.0 million for 2015 and $10.0 million for 2014 . Unrecognized compensation cost of non-vested shares totaled $ 14.1 million at December 31, 2016 . Subject to adjustment for forfeitures and changes in the fair value of 293,110 shares awarded under the Executive Incentive Plan, we expect to recognize compensation expense of $ 9.3 million in 2017 , $ 4.7 million in 2018 , and $ 89 thousand in 2019 . During January 2017, BOK Financial awarded 170,785 shares of non-vested stock with a fair value per award of $83.50 . The aggregate compensation cost of these awards totaled approximately $ 14.3 million .

Related Parties

Related Parties	12 Months Ended
	Dec. 31, 2016
Related Party Transactions [Abstract]
Related Parties [Text Block]	Related Parties In compliance with applicable banking regulations, the Company may extend credit to certain executive officers, directors, principal shareholders and their affiliates (collectively referred to as “related parties”) in the ordinary course of business. The Company’s loans to related parties do not involve more than the normal credit risk and there are no nonaccruing or impaired related party loans outstanding at December 31, 2016 or 2015 . Activity in loans to related parties is summarized as follows (in thousands): Year Ended December 31, 2016 2015 Beginning balance $ 594,225 $ 103,395 Advances 884,511 3,582,384 Payments (1,123,747 ) (3,104,004 ) Adjustments 1 (218,044 ) 12,450 Ending balance $ 136,945 $ 594,225 1 Adjustments generally consist of changes in status as a related party. As defined by banking regulations, loan commitments and equity investments to a single affiliate may not exceed 10% of unimpaired capital and surplus and loan commitments and equity investments to all affiliates may not exceed 20% of unimpaired capital and surplus. All loans to affiliates must be fully secured by eligible collateral. At December 31, 2016 , loan commitments and equity investments were limited to $287 million to a single affiliate and $573 million to all affiliates. The largest loan commitment and equity investment to a single affiliate was $220 million and the aggregate loan commitments and equity investments to all affiliates were $337 million . The largest outstanding amount to a single affiliate at December 31, 2016 was $24 million and the total outstanding amounts to all affiliates were $39 million . At December 31, 2015 , total loan commitments and equity investments to all affiliates were $330 million and the total outstanding amounts to all affiliates were $244 million . Certain related parties are customers of the Company for services other than loans, including consumer banking, corporate banking, risk management, wealth management, brokerage and trading, or fiduciary/trust services. The Company engages in transactions with related parties in the ordinary course of business in compliance with applicable regulations. The Company rents office space in facilities owned by affiliates of Mr. Kaiser, its Chairman and principal shareholder. Lease payments totaled $1.1 million for 2016, $975 thousand for 2015 and $1.1 million for 2014. During 2016, the Company agreed to purchase approximately $7.5 million of Oklahoma Historic State Income Tax Credits from the George Kaiser Family Foundation, a principal shareholder of BOKF. In the fourth quarter, $3.8 million of these tax credits were purchased and reduced the Company's state liability for 2016. The remaining credits when purchased will be used to reduce the Company's state income tax liability in 2017. Cavanal Hill Investment Management, Inc., a wholly-owned subsidiary of BOKF, NA, is the administrator to and investment advisor for the Cavanal Hill Funds (the "Funds"), a diversified, open-ended investment company established as a business trust under the Investment Company Act of 1940 (the "1940 Act"). BOKF, NA is custodian and BOK Financial Securities, Inc. is distributor for the Funds. The Funds’ products are offered to customers, employee benefit plans, trusts and the general public in the ordinary course of business. Approximately 94% of the Funds’ assets of $ 3.8 billion are held for the Company's clients. A Company executive officer serves on the Funds' board of trustees and officers of BOKF, NA serve as president and secretary of the Funds. A majority of the members of the Funds’ board of trustees are, however, independent of the Company and the Funds are managed by its board of trustees.

Commitments and Contingent Liab

Commitments and Contingent Liabilities	12 Months Ended
	Dec. 31, 2016
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingent Liabilities [Text Block]	Commitments and Contingent Liabilities Litigation Contingencies As a member of Visa, BOK Financial is obligated for a proportionate share of certain covered litigation losses incurred by Visa under a retrospective responsibility plan. A contingent liability was recognized for the Company’s share of Visa’s covered litigation liabilities. Visa funded an escrow account to cover litigation claims, including covered litigation losses under the retrospective responsibility plan, with proceeds from its initial public offering in 2008 and from available cash. BOK Financial currently owns 252,233 Visa Class B shares which are convertible into 415,755 shares of Visa Class A shares after the final settlement of all covered litigation. Class B shares may be diluted in the future if the escrow fund is not adequate to cover future covered litigation costs. Therefore, no value has been currently assigned to the Class B shares and no value may be assigned until the Class B shares are converted into a known number of Class A shares. On March 3, 2015, BOKF, NA and the Company were named as defendants in a class action alleging (1) that the manner in which the Bank posted charges to its consumer deposit accounts was improper from September 1, 2011 through July 8, 2014, the period after which the Bank and BOK Financial had settled a class action respecting a similar claim, and before it made changes to its posting order and (2) that the manner in which the Bank posted charges to its small business deposit accounts was improper from July 9, 2009 through July 8, 2014. Following mediation of the case in August 2016, the Class Representatives and the Bank reached a settlement of the action for $7.8 million . The settlement is subject to the approval of the Court which the Parties to the Action expect. The Company has funded the settlement. On June 24, 2015, the Bank received a complaint alleging that an employee had colluded with a bond issuer and an individual in misusing revenues pledged to municipal bonds for which the Bank served as trustee under the bond indenture. The Company conducted an investigation and concluded that employees in one of its Corporate Trust offices had, with respect to a single group of affiliated bond issuances, violated Company policies and procedures by waiving financial covenants, granting forbearances and accepting without disclosure to the bondholders, debt service payments from sources other than pledged revenues. The relationship manager was terminated. The Company reported the circumstances to, and cooperated with an investigation by, the Securities and Exchange Commission ("SEC"). On December 28, 2015, in an action brought by the SEC, the United States District Court for the District of New Jersey entered a judgment against the principals involved in the issuing the bonds, precluding the principals from denying the alleged violations of the federal securities laws and requiring the principals to pay all outstanding principal, accrued interest, and other amounts required under the bond documents (estimated to be approximately $73 million , less the value of the facilities securing repayment of the bonds), subject to oversight by a court appointed monitor. On September 7, 2016, the Bank agreed, and the SEC entered, a consent order finding that the Bank had violated Section 17(a) of the Securities Act of 1933 and Section 10(b) of the Securities Exchange Act and requiring the Bank to disgorge $1,067,721 of fees and pay a civil penalty of $600,000 . The Bank has disgorged the fees and paid the penalty. On January 7, 2016, the terminated employee filed an action against the Bank alleging the Bank defamed the employee and made a demand for indemnification respecting the SEC investigation which demand the respective boards of directors of the Company and the Bank denied. On September 26, 2016, the employee dismissed the action without prejudice. On September 9, 2016, the SEC filed a complaint against the terminated employee alleging the employee violated Section 17(a) of the Securities Act of 1933 and Section 10(b) of the Securities Exchange Act and requiring the employee to disgorge ill-gotten gains. The SEC and the terminated employee have advised the Court that a settlement has been reached subject to approval by the Commission. On August 26, 2016, the Bank was sued in the United States District Court for New Jersey by two bondholders in a putative class action on behalf of all holders of the bonds alleging the Bank participated in the fraudulent sale of securities by the principals. On September 14, 2016, the Bank was sued in the District Court of Tulsa County, Oklahoma by 19 bondholders alleging the Bank participated in the fraudulent sale of securities by the principals. Management has been advised by counsel that the Bank has valid defenses to the claims. The Bank expects the Court ordered payment plan will result in the payment of the bonds by the principals. Accordingly, no loss is probable at this time and no provision for loss has been made. If the payment plan does not result in payment of the bonds, a loss could become probable. A reasonable estimate cannot be made at this time though the amount could be material to the Company. The Director of the New Mexico Securities Division of the State of New Mexico Regulation and Licensing Department ("the Director") issued a Notice of Contemplated Action in connection with the purchase of various municipal bonds by the elected County Treasurer of Bernalillo County, New Mexico, from BOK Financial Securities, Inc., the Company’s broker-dealer affiliate. The Notice was settled by a $125,000 payment to the Division’s Educational fund, without any fine, penalty or sanction. The County of Bernalillo, New Mexico, has commenced arbitration pursuant to the Arbitration Rules of FINRA seeking recovery of $5.6 million arising out of the purchase. The Company has been advised that any recovery by the County is remote. In the ordinary course of business, BOK Financial and its subsidiaries are subject to legal actions and complaints. Management believes, based upon the opinion of counsel, that the actions and liability or loss, if any, resulting from the final outcomes of the proceedings, will not have a material effect on the Company’s financial condition, results of operations or cash flows. Alternative Investment Commitments The Company sponsors two private equity funds and invests in several tax credit entities and other funds as permitted by banking regulations. Consolidation of these investments is based on the variable interest model determined by the nature of the entity. Variable interest entities are generally defined as entities that either do not have sufficient equity to finance their activities without support from other parties or whose equity investors lack a controlling financial interest. Variable interest entities are consolidated based on the determination that the Company is the primary beneficiary including the power to direct the activities that most significantly impact the variable interest's economic performance and the obligation to absorb losses of the variable interest or the right to receive benefits of the variable interest that could be significant to the variable interest. BOKF Equity, LLC, an indirect wholly-owned subsidiary, is the general partner of two consolidated private equity funds (“the Funds”). The Funds provide alternative investment opportunities to certain customers, some of which are related parties, through unaffiliated limited partnerships. These unaffiliated limited partnerships generally invest in distressed assets, asset buy-outs or venture capital companies. As general partner, BOKF Equity, LLC has the power to direct activities that most significantly affect the Funds' performance and contingent obligations to make additional investments totaling $2.6 million at December 31, 2016 . Substantially all of the obligations are offset by limited partner commitments. The Company does not accrue its contingent liability to fund investments. The Volcker Rule in Title VI of the Dodd-Frank Act will limit both the amount and structure of these type of investments. Consolidated tax credit entities represent the Company's interest in entities earning federal new market tax credits related to qualifying loans for which the Company has the power to direct the activities that most significantly impact the variable interest's economic performance of the entity including being the primary beneficiary of or the obligation to absorb losses of the variable interest that could be significant to the variable interest. The creditors underlying the other borrowings of consolidated tax credit entities do not have recourse to the general credit of BOKF. The Company also has interests in various unrelated alternative investments generally consisting of unconsolidated limited partnership interests in or loans to entities for which investment return is in the form of tax credits or that invest in distressed real estate loans and properties, energy development, venture capital and other activities. The Company is prohibited by banking regulations from controlling or actively managing the activities of these investments and the Company's maximum exposure to loss is restricted to its investment balance. The Company's obligation to fund alternative investments is included in Other liabilities in the Consolidated Balance Sheets. A summary of consolidated and unconsolidated alternative investments as of December 31, 2016 and December 31, 2015 is as follows (in thousands): December 31, 2016 Loans Other Assets Other Liabilities Other Borrowings Non-controlling Interests Consolidated: Private equity funds $ — $ 17,357 $ — $ — $ 13,237 Tax credit entities 10,000 11,585 — 10,964 10,000 Other — 29,783 3,189 1,092 8,266 Total consolidated $ 10,000 $ 58,725 $ 3,189 $ 12,056 $ 31,503 Unconsolidated: Tax credit entities $ 44,488 $ 143,715 $ 63,329 $ — $ — Other — 31,675 15,028 — — Total unconsolidated $ 44,488 $ 175,390 $ 78,357 $ — $ — December 31, 2015 Loans Other Other Other Non-controlling Consolidated: Private equity funds $ — $ 22,472 $ — $ — $ 17,823 Tax credit entities 10,000 12,206 — 10,964 10,000 Other — 40,453 2,198 2,831 9,260 Total consolidated $ 10,000 $ 75,131 $ 2,198 $ 13,795 $ 37,083 Unconsolidated: Tax credit entities $ 16,916 $ 85,274 $ 14,572 $ — $ — Other — 15,506 6,319 — — Total unconsolidated $ 16,916 $ 100,780 $ 20,891 $ — $ — Other Commitments and Contingencies Cavanal Hill Funds’ assets include U.S. Treasury and government securities market funds. Assets of these funds consist of highly-rated, short-term obligations of the U.S. Treasury and Agencies. The net asset value of units in these funds was $1.00 at December 31, 2016 . An investment in these funds is not insured by the Federal Deposit Insurance Corporation or guaranteed by BOK Financial or any of its subsidiaries. BOK Financial may, but is not obligated to purchase assets from these funds to maintain the net asset value at $1.00 . No assets were purchased from the funds in 2016 or 2015 . Total rent expense for BOK Financial was $ 25.8 million in 2016 , $25.2 million in 2015 and $25.0 million in 2014 . At December 31, 2016 , future minimum lease payments for premises under operating leases were as follows: $22.5 million in 2017 , $20.1 million in 2018 , $19.6 million in 2019 , $16.2 million in 2020 , $13.4 million in 2021 and $56.8 million thereafter. BOKF, NA is obligated under a long-term lease for its bank premises in downtown Tulsa. The lease term, which began November 1, 1976, is for fifty-seven years with an option to terminate in 2024 with a two-year prior written notice. Premises leases may include options to renew at then current market rates and may include escalation provisions based upon changes in consumer price index or similar benchmarks. The Federal Reserve Bank requires member banks to maintain certain minimum average cash balances. Member banks may satisfy reserve balance requirements through holdings of vault cash and balances maintained directly with a Federal Reserve Bank. The combined average balance of vault cash and balances held at the Federal Reserve Bank was $1.9 billion for the year ended December 31, 2016 and $1.8 billion for the year ended December 31, 2015 .

Earnings Per Share

Earnings Per Share	12 Months Ended
	Dec. 31, 2016
Earnings Per Share [Abstract]
Earnings Per Share [Text Block]	Earnings Per Share The following table presents the computation of basic and diluted earnings per share (dollars in thousands, except per share data): Year Ended 2016 2015 2014 Numerator: Net income attributable to BOK Financial Corp. shareholders $ 232,668 $ 288,565 $ 292,435 Less: Earnings allocated to participating securities 2,883 3,383 3,239 Numerator for basic earnings per share – income available to common shareholders 229,785 285,182 289,196 Effect of reallocating undistributed earnings of participating securities 1 3 4 Numerator for diluted earnings per share – income available to common shareholders $ 229,786 $ 285,185 $ 289,200 Denominator: Weighted average shares outstanding 65,901,110 68,397,215 69,159,902 Less: Participating securities included in weighted average shares outstanding 815,483 802,526 765,708 Denominator for basic earnings per common share 65,085,627 67,594,689 68,394,194 Dilutive effect of employee stock compensation plans 1 58,271 96,969 150,576 Denominator for diluted earnings per common share 65,143,898 67,691,658 68,544,770 Basic earnings per share $ 3.53 $ 4.22 $ 4.23 Diluted earnings per share $ 3.53 $ 4.21 $ 4.22 1 Excludes employee stock options with exercise prices greater than current market price. — — —

Shareholders' Equity

Shareholders' Equity	12 Months Ended
	Dec. 31, 2016
Stockholders' Equity Note [Abstract]
Shareholders' Equity [Text Block]	Shareholders Equity Preferred Stock One billion shares of preferred stock with a par value of $0.00005 per share are authorized. The Series A Preferred Stock has no voting rights except as otherwise provided by Oklahoma corporate law and may be converted into one share of Common Stock for each 36 shares of Series A Preferred Stock at the option of the holder . Dividends are cumulative at an annual rate of ten percent of the $0.06 per share liquidation preference value when declared and are payable in cash. Aggregate liquidation preference is $15 million . No Series A Preferred Stock was outstanding in 2016 , 2015 or 2014 . Common Stock Common stock consists of 2.5 billion authorized shares with a $0.00006 par value. Holders of common shares are entitled to one vote per share at the election of the Board of Directors and on any question arising at any shareholders’ meeting and to receive dividends when and as declared. Additionally, regulations restrict the ability of national banks and bank holding companies to pay dividends. Subsidiary Bank The amounts of dividends that BOK Financial’s subsidiary bank can declare and the amounts of loans the subsidiary bank can extend to affiliates are limited by various federal banking regulations and state corporate law. Generally, dividends declared during a calendar year are limited to net profits, as defined, for the year plus retained profits for the preceding two years. The amounts of dividends are further restricted by minimum capital requirements. Regulatory Capital BOK Financial and the subsidiary banks are subject to various capital requirements administered by the federal banking agencies. Failure to meet minimum capital requirements can initiate certain mandatory and additional discretionary actions by regulators that could have a material effect on BOK Financial's operations. These capital requirements include quantitative measures of assets, liabilities and certain off-balance sheet items. The capital standards are also subject to qualitative judgments by the regulators. New capital rules were effective for BOK Financial on January 1, 2015. Components of these rules will phase in through January 1, 2019. A bank falling below the minimum capital requirements, including the capital conservation buffer, would be subject to regulatory restrictions on capital distributions (including but not limited to dividends and share repurchases) and executive bonus payments. For a banking institution to qualify as well capitalized, Common equity Tier 1, Tier I, Total and Leverage capital ratios must be at least 6.5% , 8% , 10% and 5% , respectively. Tier I capital consists primarily of common stockholders' equity, excluding unrealized gains or losses on available for sale securities, less goodwill, core deposit premiums and certain other intangible assets. Total capital consists primarily of Tier I capital plus preferred stock, subordinated debt and allowances for credit losses, subject to certain limitations. The subsidiary banks exceeded the regulatory definition of well capitalized as of December 31, 2016 and December 31, 2015 . A summary of regulatory capital minimum requirements and levels follows (dollars in thousands): Minimum Capital Requirement Capital Conservation Buffer 1 Minimum Capital Requirement Including Capital Conservation Buffer December 31, 2016 December 31, 2015 Common equity Tier 1 Capital (to Risk Weighted Assets): Consolidated 4.50% 2.50% 7.00% 2,834,532 11.21 % $ 2,842,193 12.13 % BOKF, NA 4.50% N/A 4.50% 2,609,450 10.65 % 2,385,323 10.26 % Mobank 2 4.50% N/A 4.50% 54,616 10.03 % N/A N/A Tier I Capital (to Risk Weighted Assets): Consolidated 6.00% 2.50% 8.50% $ 2,834,532 11.21 % $ 2,842,193 12.13 % BOKF, NA 6.00% N/A 6.00% 2,609,450 10.65 % 2,385,323 10.26 % Mobank 2 6.00% N/A 6.00% 54,616 10.03 % N/A N/A Total Capital (to Risk Weighted Assets): Consolidated 8.00% 2.50% 10.50% $ 3,238,323 12.81 % $ 3,116,144 13.30 % BOKF, NA 8.00% N/A 8.00% 2,866,949 11.70 % 2,657,935 11.43 % Mobank 2 8.00% N/A 8.00% 54,617 10.03 % N/A N/A Leverage (Tier I Capital to Average Assets): Consolidated 4.00% N/A 4.00% $ 2,834,532 8.72 % $ 2,842,193 9.25 % BOKF, NA 4.00% N/A 4.00% 2,609,450 8.11 % 2,385,323 7.81 % Mobank 2 4.00% N/A 4.00% 54,616 8.37 % N/A N/A 1 Capital conservation buffer is effective January 1, 2016 and is phased in through 2019. The phased in capital conservation buffer at December 31, 2016 is 0.625% . The fully phased in requirement of 2.50% is included in the table above. 2 Missouri Bank and Trust Company of Kansas City dba Mobank was acquired by BOK Financial effective December 1, 2016. Accumulated Other Comprehensive Income (Loss) AOCI includes unrealized gains and losses on available for sale ("AFS") securities and non-credit related unrealized losses on AFS securities for which an other-than-temporary impairment has been recorded in earnings. AOCI also includes unrealized gains on AFS securities that were transferred from AFS to investment securities in 2011. Such amounts were amortized over the estimated remaining life of the security as an adjustment to yield, offsetting the related amortization of premium on the transferred securities. Unrealized losses on employee benefit plans will be reclassified into income as pension plan costs are recognized over the remaining service period of plan participants. Accumulated losses on the interest rate lock hedge of the subordinated debt issuance in 2005 were reclassified into income over the ten-year life of the debt. Gains and losses in AOCI are net of deferred income taxes. A rollforward of the components of accumulated other comprehensive income (loss) is included as follows (in thousands): Unrealized Gain (Loss) on Available for Sale Securities Investment Securities Transferred from AFS Employee Benefit Plans Loss on Effective Cash Flow Hedges Total Balance, December 31, 2013 $ (23,175 ) $ 1,118 $ (3,311 ) $ (255 ) $ (25,623 ) Net change in unrealized gain (loss) 136,050 — 725 — 136,775 Reclassification adjustments included in earnings: Interest revenue, Investment securities, Taxable securities — (1,216 ) — — (1,216 ) Interest expense, Subordinated debentures — — — 296 296 Net impairment losses recognized in earnings 373 — — — 373 Gain on available for sale securities, net (1,539 ) — — — (1,539 ) Other comprehensive income (loss), before income taxes 134,884 (1,216 ) 725 296 134,689 Federal and state income tax 1 52,470 (474 ) 282 115 52,393 Other comprehensive income (loss), net of income taxes 82,414 (742 ) 443 181 82,296 Balance, December 31, 2014 59,239 376 (2,868 ) (74 ) 56,673 Net change in unrealized gain (loss) (48,607 ) — 1,804 — (46,803 ) Reclassification adjustments included in earnings: Interest revenue, Investment securities, Taxable securities — (503 ) — — (503 ) Interest expense, Subordinated debentures — — — 121 121 Net impairment losses recognized in earnings 1,819 — — — 1,819 Gain on available for sale securities, net (12,058 ) — — — (12,058 ) Other comprehensive income (loss), before income taxes (58,846 ) (503 ) 1,804 121 (57,424 ) Federal and state income tax 1 (22,891 ) (195 ) 701 47 (22,338 ) Other comprehensive income (loss), net of income taxes (35,955 ) (308 ) 1,103 74 (35,086 ) Balance, December 31, 2015 23,284 68 (1,765 ) — 21,587 Net change in unrealized gain (loss) (41,333 ) — (188 ) — (41,521 ) Reclassification adjustments included in earnings: Interest revenue, Investment securities, Taxable securities — (112 ) — — (112 ) Interest expense, Subordinated debentures — — — — — Net impairment losses recognized in earnings — — — — — Gain on available for sale securities, net (11,675 ) — — — (11,675 ) Other comprehensive income (loss), before income taxes (53,008 ) (112 ) (188 ) — (53,308 ) Federal and state income tax 1 (20,637 ) (44 ) (73 ) — (20,754 ) Other comprehensive income (loss), net of income taxes (32,371 ) (68 ) (115 ) — (32,554 ) Balance, December 31, 2016 $ (9,087 ) $ — $ (1,880 ) $ — $ (10,967 ) 1 Calculated using 39% effective tax rate.

Reportable Segments

Reportable Segments	12 Months Ended
	Dec. 31, 2016
Segment Reporting [Abstract]
Reportable Segments [Text Block]	Reportable Segments BOK Financial operates three principal lines of business: Commercial Banking, Consumer Banking and Wealth Management. Commercial Banking includes lending, treasury and cash management services and customer risk management products to small businesses, middle market and larger commercial customers. Commercial Banking also includes the TransFund EFT network. Consumer Banking includes retail lending and deposit services, lending and deposit services to small business customers served through the consumer branch network and all mortgage banking activities. Wealth Management provides fiduciary services, private bank services and investment advisory services in all markets. Wealth Management also underwrites state and municipal securities and engages in brokerage and trading activities. In addition to its lines of business, BOK Financial has a Funds Management unit. The primary purpose of this unit is to manage overall liquidity needs and interest rate risk. Each line of business borrows funds from and provides funds to the Funds Management unit as needed to support their operations. Operating results for Funds Management and other include the effect of interest rate risk positions and risk management activities, securities gains and losses including impairment charges, the provision for credit losses in excess of net loans charged off, tax planning strategies and certain executive compensation costs that are not attributed to the lines of business. BOK Financial allocates resources and evaluates performance of its lines of business after allocation of funds, actual net credit losses and capital costs. In addition, we measure the performance of our business lines after allocation of certain indirect expenses and taxes on statutory rates. The allocation for the prior comparable periods have been revised on a comparable basis. The cost of funds borrowed from the Funds Management unit by the operating lines of business is transfer priced at rates that approximate market rates for funds with similar duration. Market rates are generally based on the applicable LIBOR or interest rate swap rates, adjusted for prepayment risk. This method of transfer-pricing funds that support assets of the operating lines of business tends to insulate them from interest rate risk. The value of funds provided by the operating lines of business to the Funds Management unit is based on rates which approximate the wholesale market rates for funds with similar duration and re-pricing characteristics. Market rates are generally based on LIBOR or interest rate swap rates. The funds credit formula applied to deposit products with indeterminate maturities is established based on their re-pricing characteristics reflected in a combination of the short-term LIBOR rates and a moving average of an intermediate term swap rate, with an appropriate spread applied to both. Shorter duration products are weighted towards the short-term LIBOR rate and longer duration products are weighted towards intermediate swap rates. The expected duration ranges from 30 days for certain rate-sensitive deposits to five years. Substantially all revenue is from domestic customers. No single external customer accounts for more than 10% of total revenue. Net loans charged off and provision for credit losses represents net loans charged off as attributed to the lines of business and the provision for credit losses in excess of net charge-offs attributed to Funds Management and Other. The acquisition of Mobank on December 1, 2016 was not yet allocated to the operating segments at December 31, 2016. Accordingly, the operation, assets and liabilities of Mobank were included in Funds Management and Other for 2016. Reportable segments reconciliation to the Consolidated Financial Statements for the year ended December 31, 2016 is as follows (in thousands): Commercial Consumer Wealth Management Funds Management and Other BOK Financial Consolidated Net interest and dividend revenue from external sources $ 492,967 $ 85,998 $ 33,006 $ 135,257 $ 747,228 Net interest revenue (expense) from internal sources (58,781 ) 37,777 29,043 (8,039 ) — Net interest and dividend revenue 434,186 123,775 62,049 127,218 747,228 Provision for credit losses 32,959 4,927 (801 ) 27,915 65,000 Net interest and dividend revenue after provision for credit losses 401,227 118,848 62,850 99,303 682,228 Other operating revenue 195,521 224,802 283,222 (29,525 ) 674,020 Other operating expense 216,451 249,744 250,994 300,401 1,017,590 Net direct contribution 380,297 93,906 95,078 (230,623 ) 338,658 Gain (loss) on financial instruments, net 10 (26,252 ) (42 ) 26,284 — Change in fair value of mortgage servicing rights — (2,193 ) — 2,193 — Gain (loss) on repossessed assets, net 669 979 — (1,648 ) — Corporate expense allocations 35,760 66,411 42,378 (144,549 ) — Net income before taxes 345,216 29 52,658 (59,245 ) 338,658 Federal and state income taxes 134,289 11 20,484 (48,407 ) 106,377 Net income 210,927 18 32,174 (10,838 ) 232,281 Net income (loss) attributable to non-controlling interests — — — (387 ) (387 ) Net income attributable to BOK Financial Corp. shareholders $ 210,927 $ 18 $ 32,174 $ (10,451 ) $ 232,668 Average assets $ 16,998,626 $ 8,722,372 $ 6,281,127 $ 276,277 $ 32,278,402 Reportable segments reconciliation to the Consolidated Financial Statements for the year ended December 31, 2015 is as follows (in thousands): Commercial Consumer Wealth Management Funds Management and Other BOK Financial Consolidated Net interest and dividend revenue from external sources $ 439,751 $ 84,848 $ 24,744 $ 154,011 $ 703,354 Net interest revenue (expense) from internal sources (52,313 ) 28,503 24,043 (233 ) — Net interest and dividend revenue 387,438 113,351 48,787 153,778 703,354 Provision for credit losses (6,748 ) 6,934 (1,083 ) 34,897 34,000 Net interest and dividend revenue after provision for credit losses 394,186 106,417 49,870 118,881 669,354 Other operating revenue 177,729 218,095 267,523 (4,867 ) 658,480 Other operating expense 202,804 203,070 228,664 261,653 896,191 Net direct contribution 369,111 121,442 88,729 (147,639 ) 431,643 Gain (loss) on financial instruments, net — (4,712 ) (204 ) 4,916 — Change in fair value of mortgage servicing rights — (4,853 ) — 4,853 — Gain (loss) on repossessed assets, net 708 916 — (1,624 ) — Corporate expense allocations 43,279 74,936 40,357 (158,572 ) — Net income before taxes 326,540 37,857 48,168 19,078 431,643 Federal and state income taxes 127,024 14,726 18,737 (21,103 ) 139,384 Net income 199,516 23,131 29,431 40,181 292,259 Net income attributable to non-controlling interests — — — 3,694 3,694 Net income attributable to BOK Financial Corp. shareholders $ 199,516 $ 23,131 $ 29,431 $ 36,487 $ 288,565 Average assets $ 16,284,527 $ 8,836,327 $ 5,444,483 $ 9,418 $ 30,574,755 Reportable segments reconciliation to the Consolidated Financial Statements for the year ended December 31, 2014 is as follows (in thousands): Commercial Consumer Wealth Management Funds Management and Other BOK Financial Consolidated Net interest and dividend revenue from external sources $ 382,331 $ 81,852 $ 23,817 $ 177,194 $ 665,194 Net interest revenue (expense) from internal sources (40,083 ) 26,813 20,959 (7,689 ) — Net interest and dividend revenue 342,248 108,665 44,776 169,505 665,194 Provision for credit losses (7,447 ) 5,477 213 1,757 — Net interest and dividend revenue after provision for credit losses 349,695 103,188 44,563 167,748 665,194 Other operating revenue 171,390 214,657 242,268 (6,357 ) 621,958 Other operating expense 195,706 207,131 218,000 226,685 847,522 Net direct contribution 325,379 110,714 68,831 (65,294 ) 439,630 Gain (loss) on financial instruments, net — 12,406 (235 ) (12,171 ) — Change in fair value of mortgage servicing rights — (16,445 ) — 16,445 — Gain (loss) on repossessed assets, net (3,187 ) 1,418 — 1,769 — Corporate expense allocations 45,502 64,531 38,731 (148,764 ) — Net income before taxes 276,690 43,562 29,865 89,513 439,630 Federal and state income taxes 107,632 16,946 11,617 7,956 144,151 Net income 169,058 26,616 18,248 81,557 295,479 Net income attributable to non-controlling interests — — — 3,044 3,044 Net income attributable to BOK Financial Corp. shareholders $ 169,058 $ 26,616 $ 18,248 $ 78,513 $ 292,435 Average assets $ 15,394,957 $ 8,373,317 $ 5,002,515 $ (771,931 ) $ 27,998,858

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2016
Fair Value Disclosures [Abstract]
Fair Value Measurements [Text Block]	Fair Value Measurements Fair value is defined by applicable accounting guidance as the price to sell an asset or transfer a liability in an orderly transaction between market participants in the principal market for the given asset or liability at the measurement date based on market conditions at that date. An orderly transaction assumes exposure to the market for a customary period for marketing activities prior to the measurement date and not a forced liquidation or distressed sale. Certain assets and liabilities are recorded in the Company’s financial statements at fair value. Some are recorded on a recurring basis and some on a non-recurring basis. For some assets and liabilities, observable market transactions and market information might be available. For other assets and liabilities, observable market transactions and market information might not be available. A hierarchy for fair value has been established which categorizes into three levels the inputs to valuation techniques used to measure fair value. The three levels are as follows: Quoted Prices in Active Markets for Identical Assets or Liabilities (Level 1) - fair value is based on unadjusted quoted prices in active markets for identical assets or liabilities. Significant Other Observable Inputs (Level 2) - fair value is based on significant other observable inputs which are generally determined based on a single price for each financial instrument provided to us by an applicable third-party pricing service and is based on one or more of the following: • Quoted prices for similar, but not identical, assets or liabilities in active markets; • Quoted prices for identical or similar assets or liabilities in inactive markets; • Inputs other than quoted prices that are observable, such as interest rate and yield curves, volatilities, prepayment speeds, loss severities, credit risks and default rates; • Other inputs derived from or corroborated by observable market inputs. Significant Unobservable Inputs (Level 3) - fair value is based upon model-based valuation techniques for which at least one significant assumption is not observable in the market. Transfers between levels are recognized as of the end of the reporting period. There were no transfers in or out of quoted prices in active markets for identical instruments to significant other observable inputs or significant unobservable inputs during the year ended December 31, 2016 and 2015 , respectively. Transfers between significant other observable inputs and significant unobservable inputs during the year ended December 31, 2016 and 2015 are included in the summary of changes in recurring fair values measured using unobservable inputs. The underlying methods used by the third-party pricing services are considered in determining the primary inputs used to determine fair values. Management has evaluated the methodologies employed by the third-party pricing services by comparing the price provided by the pricing service with other sources, including brokers' quotes, sales or purchases of similar instruments and discounted cash flows to establish a basis for reliance on the pricing service values. Significant differences between the pricing service provided value and other sources are discussed with the pricing service to understand the basis for their values. Based on all observable inputs, management may adjust prices obtained from third-party pricing services to more appropriately reflect the prices that would be received to sell assets or paid to transfer liabilities in orderly transactions in the current market. No significant adjustments were made to prices provided by third-party pricing services at December 31, 2016 and 2015 . Assets and Liabilities Measured at Fair Value on a Recurring Basis The fair value of financial assets and liabilities that are measured on a recurring basis is as follows as of December 31, 2016 (in thousands): Total Quoted Prices in Active Markets for Identical Instruments Significant Other Observable Inputs Significant Unobservable Inputs Assets: Trading securities: U.S. government agency debentures $ 6,234 $ — $ 6,234 $ — U.S. agency residential mortgage-backed securities 310,067 — 310,067 — Municipal and other tax-exempt securities 14,427 — 14,427 — Other trading securities 6,900 — 6,900 — Total trading securities 337,628 — 337,628 — Available for sale securities: U.S. Treasury securities 999 999 — — Municipal and other tax-exempt securities 40,993 — 35,204 5,789 U.S. government agency residential mortgage-backed securities 5,460,386 — 5,460,386 — Privately issued residential mortgage-backed securities 115,535 — 115,535 — Commercial mortgage-backed securities guaranteed by U.S. government agencies 3,017,933 — 3,017,933 — Other debt securities 4,152 — — 4,152 Perpetual preferred stock 18,474 — 18,474 — Equity securities and mutual funds 18,357 3,495 14,862 — Total available for sale securities 8,676,829 4,494 8,662,394 9,941 Fair value option securities – U.S. government agency residential mortgage-backed securities 77,046 — 77,046 — Residential mortgage loans held for sale 301,897 — 290,280 11,617 Mortgage servicing rights, net 1 247,073 — — 247,073 Derivative contracts, net of cash margin 2 689,872 7,541 682,331 — Liabilities: Derivative contracts, net of cash margin 2 664,531 6,972 657,559 — 1 A reconciliation of the beginning and ending fair value of mortgage servicing rights and disclosures of significant assumptions used to determine fair value are presented in Note 7 , Mortgage Banking Activities. 2 See Note 3 for detail of fair value of derivative contracts by contract type. Derivative contracts in a net asset position that were valued based on quoted prices in active markets or identical instruments (Level 1) are exchange-traded interest rate and energy derivative contracts, net of cash margin. Derivative contracts in a net liability position that were valued using quoted prices in active markets for identical instruments (Level 1) are exchange-traded interest rate, energy and agricultural derivative contracts, net of cash margin. The fair value of financial assets and liabilities that are measured on a recurring basis is as follows as of December 31, 2015 (in thousands): Total Quoted Prices in Active Markets for Identical Instruments Significant Other Observable Inputs Significant Unobservable Inputs Assets: Trading securities: U.S. government agency debentures $ 61,295 $ — $ 61,295 $ — U.S. government agency residential mortgage-backed securities 10,989 — 10,989 — Municipal and other tax-exempt securities 31,901 — 31,901 — Other trading securities 18,219 — 18,219 — Total trading securities 122,404 — 122,404 — Available for sale securities: U.S. Treasury securities 995 995 — — Municipal and other tax-exempt securities 56,817 — 47,207 9,610 U.S. government agency residential mortgage-backed securities 5,898,351 — 5,898,351 — Privately issued residential mortgage-backed securities 139,118 — 139,118 — Commercial mortgage-backed securities guaranteed by U.S. government agencies 2,905,796 — 2,905,796 — Other debt securities 4,151 — — 4,151 Perpetual preferred stock 19,672 — 19,672 — Equity securities and mutual funds 17,833 3,265 14,568 — Total available for sale securities 9,042,733 4,260 9,024,712 13,761 Fair value option securities – U.S. government agency residential mortgage-backed securities 444,217 — 444,217 — Residential mortgage loans held for sale 308,439 — 300,565 7,874 Mortgage servicing rights, net 1 218,605 — — 218,605 Derivative contracts, net of cash margin 2 586,270 38,530 547,740 — Liabilities: Derivative contracts, net of cash margin 2 581,701 — 581,701 — 1 A reconciliation of the beginning and ending fair value of mortgage servicing rights and disclosures of significant assumptions used to determine fair value are presented in Note 7 , Mortgage Banking Activities. 2 See Note 3 for detail of fair value of derivative contracts by contract type. Derivative contracts in a net asset position that were valued based on quoted prices in active markets for identical instruments (Level 1) are exchange-traded energy derivative contracts, net of cash margin. Derivative contracts in a net liability position that were valued using quoted prices in active markets for identical instruments based on quoted prices in active markets for identical instruments (Level 1) are exchange-traded interest rate and agricultural derivative contracts, fully offset by cash margin. Following is a description of the Company's valuation methodologies used for assets and liabilities measured on a recurring basis: Securities The fair values of trading, available for sale and fair value option securities are based on quoted prices for identical instruments in active markets, when available. If quoted prices for identical instruments are not available, fair values are based on significant other observable inputs such as quoted prices of comparable instruments or interest rates and credit spreads, yield curves, volatilities, prepayment speeds and loss severities. The fair value of certain available for sale municipal and other debt securities may be based on significant unobservable inputs. These significant unobservable inputs include limited observed trades, projected cash flows, current credit rating of the issuers and, when applicable, the insurers of the debt and observed trades of similar debt. Discount rates are primarily based on reference to interest rate spreads on comparable securities of similar duration and credit rating as determined by the nationally-recognized rating agencies adjusted for a lack of trading volume. Significant unobservable inputs are developed by investment securities professionals involved in the active trading of similar securities. A summary of significant inputs used to value these securities follows. A management committee composed of senior members from the Company's Capital Markets, Risk Management and Finance departments assess the appropriateness of these inputs quarterly. Derivatives All derivative instruments are carried on the balance sheet at fair value. Fair values for exchange-traded contracts are based on quoted prices. Fair values for over-the-counter interest rate, commodity and foreign exchange contracts are based on valuations provided either by third-party dealers in the contracts, quotes provided by independent pricing services, or a third-party provided pricing model that uses significant other observable market inputs. Credit risk is considered in determining the fair value of derivative instruments. Management determines fair value adjustments based on various risk factors including but not limited to counterparty credit rating or equivalent loan grading, derivative contract notional size, price volatility of the underlying commodity, duration of the derivative contracts and expected loss severity. Expected loss severity is based on historical losses for similarly risk graded commercial loan customers. Decreases in counterparty credit rating or grading and increases in price volatility and expected loss severity all tend to increase the credit quality adjustment which reduces the fair value of asset contracts. We also consider our own credit risk in determining the fair value of derivative contracts. Changes in our credit rating would affect the fair value of our derivative liabilities. In the event of a credit downgrade, the fair value of our derivative liabilities would increase. The change in the fair value would be recognized in earnings in the current period. Residential Mortgage Loans Held for Sale Residential mortgage loans held for sale are carried on the balance sheet at fair value. The fair values of conforming residential mortgage loans held for sale are based upon quoted market prices of such loans sold in securitization transactions, including related unfunded loan commitments. The fair value of mortgage loans that are unable to be sold to U.S. government agencies is determined using quoted prices of loans that are sold in securitization transactions with a liquidity discount applied. Other Assets - Private Equity Funds The fair value of the portfolio investments of the Company's two private equity funds are based upon net asset value reported by the underlying funds, as adjusted by the general partner when necessary, as a practical expedient to measure the fair value of the investments in the underlying funds. The Company's private equity funds provide customers alternative investment opportunities as limited partners of the funds. As fund of funds, the private equity funds invest in other limited partnerships or limited liability companies that invest substantially all of their assets in U.S. companies pursuing diversified investment strategies including early-stage venture capital, distressed securities and corporate or asset buy-outs. Private equity fund assets are long-term, illiquid investments. No secondary market exists for these assets. The private equity funds typically invest in funds that provide no redemption rights to investors. The fair value of the private equity investments may only be realized through cash distributions from the underlying funds. See Note 14 for disclosure of the fair value of the private equity funds using the net asset value per share of the underlying investments, as a practical expedient, included in Other assets in the Consolidated Balance Sheets of the Company. The following represents the changes related to assets measured at fair value on a recurring basis using significant unobservable inputs (in thousands): Available for Sale Securities Residential mortgage loans held for sale Municipal and other tax-exempt securities Other debt securities Balance, December 31, 2014 $ 10,093 $ 4,150 $ 11,856 Transfer to Level 3 from Level 2 1 — — 2,193 Purchases and capital calls — — — Redemptions and distributions — — — Proceeds from sales — — (6,283 ) Gain (loss) recognized in earnings: Mortgage banking revenue — — 108 Other comprehensive income (loss): Net change in unrealized gain (loss) (483 ) 1 — Balance, December 31, 2015 9,610 4,151 7,874 Transfer to Level 3 from Level 2 1 — — 6,631 Purchases and capital calls — — — Redemptions and distributions (3,975 ) — — Proceeds from sales — — (2,540 ) Gain (loss) recognized in earnings: Mortgage banking revenue — — (348 ) Other comprehensive income (loss): Net change in unrealized gain (loss) 154 1 — Balance, December 31, 2016 $ 5,789 $ 4,152 $ 11,617 1 Recurring transfers to Level 3 from Level 2 consist of residential mortgage loans intended for sale to U.S. government agencies that fail to meet conforming standards. A summary of quantitative information about assets measured at fair value on a recurring basis using significant unobservable inputs (Level 3) as of December 31, 2016 follows (in thousands): Quantitative Information about Level 3 Recurring Fair Value Measurements Par Value Amortized Cost/Unpaid Principal Balance Fair Value Valuation Technique(s) Significant Unobservable Input Range (Weighted Average) Available for sale securities: Municipal and other tax-exempt securities $ 6,195 $ 6,163 $ 5,712 Discounted cash flows 1 Interest rate spread 5.91%-6.21% (6.16%) 2 90.00%-93.40% (92.20%) 3 Other debt securities 4,400 4,400 4,152 Discounted cash flows 1 Interest rate spread 6.01% - 6.26% (6.23%) 4 94.34% - 94.36% (94.36%) 3 Residential mortgage loans held for sale N/A 12,431 11,617 Quoted prices of loans sold in securitization transactions, with a liquidity discount applied Liquidity discount applied to the market value of mortgage loans qualifying for sale to U.S. government agencies 93.45% 1 Discounted cash flows developed using discount rates primarily based on reference to interest rate spreads for comparable securities of similar duration and credit rating as determined by the nationally-recognized rating agencies, adjusted for lack of trading volume. 2 Interest rate yields used to value investment grade tax-exempt securities represent a spread of 467 to 525 basis points over average yields for comparable tax-exempt securities. 3 Represents fair value as a percentage of par value. 4 Interest rate yields used to value investment grade taxable securities based on comparable short-term taxable securities which are generally yielding approximately 1% . A summary of quantitative information about Recurring Fair Value Measurements based on Significant Unobservable Inputs (Level 3) as of December 31, 2015 follows (in thousands): Quantitative Information about Level 3 Recurring Fair Value Measurements Par Value Amortized Cost 6 Fair Value Valuation Technique(s) Significant Unobservable Input Range (Weighted Average) Available for sale securities: Municipal and other tax-exempt securities $ 10,370 $ 10,311 $ 9,610 Discounted cash flows 1 Interest rate spread 5.47%-5.77% (5.73%) 2 92.34%-92.93% (92.67%) 3 Other debt securities 4,400 4,400 4,151 Discounted cash flows 1 Interest rate spread 5.80% - 5.92% (5.90%) 4 94.33% - 94.34% (94.34%) 3 Residential mortgage loans held for sale N/A 8,395 7,874 Quoted prices of loans sold in securitization transactions, with a liquidity discount applied Liquidity discount applied to the market value of mortgage loans qualifying for sale to U.S. government agencies 93.79% 1 Discounted cash flows developed using discount rates primarily based on reference to interest rate spreads for comparable securities of similar duration and credit rating as determined by the nationally-recognized rating agencies, adjusted for lack of trading volume. 2 Interest rate yields used to value investment grade tax-exempt securities represent a spread of 499 to 541 basis points over average yields for comparable tax-exempt securities. 3 Represents fair value as a percentage of par value. 4 Interest rate yields used to value investment grade taxable securities based on comparable short-term taxable securities which are generally yielding less than 1% . Fair Value of Assets and Liabilities Measured on a Non-Recurring Basis Assets measured at fair value on a non-recurring basis include pension plan assets, which are based on quoted prices in active markets for identical instruments, collateral for certain impaired loans and real property and other assets acquired to satisfy loans, which are based primarily on comparisons to completed sales of similar assets. See Note 6 for information related to the non-recurring fair value measurement of Mobank. The following represents the carrying value of assets measured at fair value on a non-recurring basis and related losses recorded during the year. The carrying value represents only those assets with the balance sheet date for which the fair value was adjusted during the year: Carrying Value at December 31, 2016 Fair Value Adjustments for the Quoted Prices in Active Markets for Identical Instruments Significant Other Observable Inputs Significant Unobservable Inputs Gross charge-offs against allowance for loan losses Net losses and expenses of repossessed assets, net Impaired loans $ — $ 539 $ 11,295 $ 7,594 $ — Real estate and other repossessed assets — 7,965 2,192 — 2,527 Carrying Value at December 31, 2015 Fair Value Adjustments for the Quoted Prices in Active Markets for Identical Instruments Significant Other Observable Inputs Significant Unobservable Inputs Gross charge-offs against allowance for loan losses Net losses and expenses of repossessed assets, net Impaired loans $ — $ 252 $ 20,805 $ 4,042 $ — Real estate and other repossessed assets — 13,611 245 — 1,820 The fair value of collateral-dependent impaired loans and real estate and other repossessed assets and the related fair value adjustments are generally based on unadjusted third-party appraisals. Our appraisal review policies require appraised values to be supported by observed inputs derived principally from or corroborated by observable market data. Appraisals that are not based on observable inputs or that require significant adjustments or fair value measurements that are not based on third-party appraisals are considered to be based on significant unobservable inputs. Non-recurring fair value measurements of collateral-dependent impaired loans and real estate and other repossessed assets based on significant unobservable inputs are generally due to estimates of current fair values between appraisal dates. Significant unobservable inputs include listing prices for comparable assets, uncorroborated expert opinions or management's knowledge of the collateral or industry. Non-recurring fair value measurements of collateral dependent loans secured by mineral rights are generally determined by our internal staff of engineers on projected cash flows under current market conditions and are based on significant unobservable inputs. Projected cash flows are discounted according to risk characteristics of the underlying oil and gas properties. Assets are evaluated to demonstrate with reasonable certainty that crude oil, natural gas and natural gas liquids can be recovered from known oil and gas reservoirs under existing economic and operating conditions at current prices with existing conventional equipment, operating methods and costs. Significant unobservable inputs are developed by asset management and workout professionals and approved by senior Credit Administration executives. A summary of quantitative information about Non-recurring Fair Value Measurements based on Significant Unobservable Inputs (Level 3) as of December 31, 2016 follows (in thousands): Quantitative Information about Level 3 Non-recurring Fair Value Measurements Fair Value Valuation Technique(s) Significant Unobservable Input Range (Weighted Average) Impaired loans $ 11,295 Appraised value, as adjusted Recoverable oil and gas reserves, forward-looking commodity prices and estimated operating costs 22% - 59% (57%) 1 Real estate and other repossessed assets 2,192 Appraised value, as adjusted Marketability adjustments off appraised value 2 70% - 87% (74%) 1 Represents fair value as a percentage of the unpaid principal balance. 2 Marketability adjustments include consideration of estimated costs to sell which is approximately 10% of the fair value. A summary of quantitative information about Non-recurring Fair Value Measurements based on Significant Unobservable Inputs (Level 3) as of December 31, 2015 follows (in thousands): Quantitative Information about Level 3 Non-recurring Fair Value Measurements Fair Value Valuation Technique(s) Significant Unobservable Input Range (Weighted Average) Impaired loans $ 20,805 Appraised value, as adjusted Broker quotes and management's knowledge of industry and collateral. N/A Real estate and other repossessed assets 245 Appraised value, as adjusted Marketability adjustments off appraised value 1 66%-81% (74%) 1 Marketability adjustments include consideration of estimated costs to sell which is approximately 10% of the fair value. The fair value of pension plan assets was approximately $42 million at December 31, 2016 and $44 million at December 31, 2015 , determined by significant other observable inputs. Fair value adjustments of pension plan assets along with changes in the projected benefit obligation are recognized in other comprehensive income. Fair Value of Financial Instruments The following table presents the carrying values and estimated fair values of all financial instruments, including those financial assets and liabilities that are not measured and reported at fair value on a recurring basis or non-recurring (dollars in thousands): December 31, 2016 Carrying Value Estimated Fair Value Quoted Prices in Active Markets for Identical Instruments (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Cash and due from banks $ 620,846 620,846 620,846 — — Interest-bearing cash and cash equivalents 1,916,651 1,916,651 1,916,651 — — Trading securities: U.S. government agency debentures 6,234 6,234 — 6,234 — U.S. government agency residential mortgage-backed securities 310,067 310,067 — 310,067 — Municipal and other tax-exempt securities 14,427 14,427 — 14,427 — Other trading securities 6,900 6,900 — 6,900 — Total trading securities 337,628 337,628 — 337,628 — Investment securities: Municipal and other tax-exempt securities 320,364 321,225 — 321,225 — U.S. government agency residential mortgage-backed securities 20,777 21,473 — 21,473 — Other debt securities 205,004 222,795 — 222,795 — Total investment securities 546,145 565,493 — 565,493 — Available for sale securities: U.S. Treasury securities 999 999 999 — — Municipal and other tax-exempt securities 40,993 40,993 — 35,204 5,789 U.S. government agency residential mortgage-backed securities 5,460,386 5,460,386 — 5,460,386 — Privately issued residential mortgage-backed securities 115,535 115,535 — 115,535 — Commercial mortgage-backed securities guaranteed by U.S. government agencies 3,017,933 3,017,933 — 3,017,933 — Other debt securities 4,152 4,152 — — 4,152 Perpetual preferred stock 18,474 18,474 — 18,474 — Equity securities and mutual funds 18,357 18,357 3,495 14,862 — Total available for sale securities 8,676,829 8,676,829 4,494 8,662,394 9,941 Fair value option securities – U.S. government agency residential mortgage-backed securities 77,046 77,046 — 77,046 — Residential mortgage loans held for sale 301,897 301,897 — 290,280 11,617 Loans: Commercial 10,390,824 10,437,016 — — 10,437,016 Commercial real estate 3,809,046 3,850,981 — — 3,850,981 Residential mortgage 1,949,832 2,025,159 — — 2,025,159 Personal 839,958 864,904 — — 864,904 Total loans 16,989,660 17,178,060 — — 17,178,060 Allowance for loan losses (246,159 ) — — — — Loans, net of allowance 16,743,501 17,178,060 — — 17,178,060 Mortgage servicing rights 247,073 247,073 — — 247,073 Derivative instruments with positive fair value, net of cash margin 689,872 689,872 7,541 682,331 — Deposits with no stated maturity 20,526,295 20,526,295 — — 20,526,295 Time deposits 2,221,800 2,218,303 — — 2,218,303 Other borrowed funds 5,572,662 5,556,327 — — 5,556,327 Subordinated debentures 144,640 128,903 — 128,903 — Derivative instruments with negative fair value, net of cash margin 664,531 664,531 6,972 657,559 — December 31, 2015 Carrying Value Estimated Fair Value Quoted Prices in Active Markets for Identical Instruments (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Cash and due from banks $ 573,699 $ 573,699 573,699 — $ — Interest-bearing cash and cash equivalents 2,069,900 2,069,900 2,069,900 — — Trading securities: U.S. government agency debentures 61,295 61,295 — 61,295 — U.S. government agency residential mortgage-backed securities 10,989 10,989 — 10,989 — Municipal and other tax-exempt securities 31,901 31,901 — 31,901 — Other trading securities 18,219 18,219 — 18,219 — Total trading securities 122,404 122,404 — 122,404 — Investment securities: Municipal and other tax-exempt securities 365,258 368,910 — 368,910 — U.S. government agency residential mortgage-backed securities 26,833 27,874 — 27,874 — Other debt securities 205,745 232,375 — 232,375 — Total investment securities 597,836 629,159 — 629,159 — Available for sale securities: U.S. Treasury securities 995 995 995 — — Municipal and other tax-exempt securities 56,817 56,817 — 47,207 9,610 U.S. government agency residential mortgage-backed securities 5,898,351 5,898,351 — 5,898,351 — Privately issued residential mortgage-backed securities 139,118 139,118 — 139,118 — Commercial mortgage-backed securities guaranteed by U.S. government agencies 2,905,796 2,905,796 — 2,905,796 — Other debt securities 4,151 4,151 — — 4,151 Perpetual preferred stock 19,672 19,672 — 19,672 — Equity securities and mutual funds 17,833 17,833 3,265 14,568 — Total available for sale securities 9,042,733 9,042,733 4,260 9,024,712 13,761 Fair value option securities – U.S. government agency residential mortgage-backed securities 444,217 444,217 — 444,217 — Residential mortgage loans held for sale 308,439 308,439 — 300,565 7,874 Loans: Commercial 10,252,531 10,053,952 — — 10,053,952 Commercial real estate 3,259,033 3,233,476 — — 3,233,476 Residential mortgage 1,876,893 1,902,976 — — 1,902,976 Personal 552,697 549,068 — — 549,068 Total loans 15,941,154 15,739,472 — — 15,739,472 Allowance for loan losses (225,524 ) — — — — Loans, net of allowance 15,715,630 15,739,472 — — 15,739,472 Mortgage servicing rights 218,605 218,605 — — 218,605 Derivative instruments with positive fair value, net of cash margin 586,270 586,270 38,530 547,740 — Deposits with no stated maturity 18,682,094 18,682,094 — — 18,682,094 Time deposits 2,406,064 2,394,562 — — 2,394,562 Other borrowed funds 6,051,515 5,600,932 — — 5,600,932 Subordinated debentures 226,350 223,758 — — 223,758 Derivative instruments with negative fair value, net of cash margin 581,701 581,701 — 581,701 — Because no market exists for certain of these financial instruments and management does not intend to sell these financial instruments, the fair values shown in the tables above may not represent values at which the respective financial instruments could be sold individually or in the aggregate at the given reporting date. The following methods and assumptions were used in estimating the fair value of these financial instruments: Cash and Cash Equivalents The book value reported in the consolidated balance sheet for cash and short-term instruments approximates those assets’ fair values. Securities The fair values of securities are generally based on Significant Other Observable Inputs such as quoted prices for comparable instruments or interest rates and credit spreads, yield curves, volatilities, prepayment speeds and loss severities. Loans The fair value of loans, excluding loans held for sale, are based on discounted cash flow analyses using interest rates and credit and liquidity spreads currently being offered for loans with similar remaining terms to maturity and risk, adjusted for the impact of interest rate floors and ceilings which are classified as Significant Unobservable Inputs. The fair values of loans were estimated to approximate their discounted cash flows less loan loss allowances allocated to these loans of $218 million at December 31, 2016 and $195 million at December 31, 2015 . A summary of assumptions used in determining the fair value of loans follows: Range of Average Discount December 31, 2016 Commercial 0.38% - 30.00% 0.70 0.64% - 4.60% Commercial real estate 0.38% - 18.00% 0.71 0.94% - 4.27% Residential mortgage 1.74% - 18.00% 2.27 1.71% - 4.26% Personal 0.25% - 21.00% 0.40 1.03% - 4.59% December 31, 2015 Commercial 0.25% - 30.00% 0.62 0.52% - 4.34% Commercial real estate 0.38% - 18.00% 0.73 0.95% - 3.93% Residential mortgage 1.67% - 18.00% 2.42 0.86% - 4.25% Personal 0.38% - 21.00% 0.37 1.19% - 4.11% Deposits The fair values of time deposits are based on discounted cash flow analyses using interest rates currently being offered on similar transactions which are considered Significant Unobservable Inputs. Estimated fair value of deposits with no stated maturity, which includes demand deposits, transaction deposits, money market deposits and savings accounts, is equal to the amount payable on demand. Although market premiums paid reflect an additional value for these low cost deposits, adjusting fair value for the expected benefit of these deposits is prohibited. Accordingly, the positive effect of such deposits is not included in the tables above.A summary of assumptions used in determining the fair value of time deposits follows: Range of Average Discount December 31, 2016 0.02% - 9.65% 1.96 1.57% - 2.00% December 31, 2015 0.02% - 5.50% 1.78 1.11% - 1.57% Other Borrowed Funds and Subordinated Debentures The fair values of these instruments are based upon discounted cash flow analyses using interest rates currently being offered on similar instruments which are considered Significant Unobservable Inputs. A summary of assumptions used in determining the fair value of other borrowings and subordinated debentures follows: Range of Average Discount December 31, 2016 Other borrowed funds 0.25% - 3.50% 0.00 0.55% - 3.22% Subordinated debentures 5.38% 16.86 6.11% December 31, 2015 Other borrowed funds 0.25% - 3.40% 0.00 0.20% - 2.89% Subordinated debentures 1.05% 1.37 2.12% Off-Balance Sheet Instruments The fair values of commercial loan commitments are based on fees currently charged to enter into similar agreements, taking into account the remaining terms of the agreements. The fair values of these off-balance sheet instruments were not significant at December 31, 2016 or December 31, 2015 . Fair Value Election As more fully disclosed in Note 2 and Not

Parent Company Only Financial S

Parent Company Only Financial Statements Parent Company Only Financial Statements	12 Months Ended
	Dec. 31, 2016
Condensed Financial Information of Parent Company Only Disclosure [Abstract]
Condensed Financial Information of Parent Company Only Disclosure [Text Block]	Parent Company Only Financial Statements Summarized financial information for BOK Financial – Parent Company Only follows: Balance Sheets (In thousands) December 31, 2016 2015 Assets Cash and cash equivalents $ 163,418 $ 282,169 Available for sale securities 19,234 20,150 Investment in bank subsidiaries 3,067,595 2,746,810 Investment in non-bank subsidiaries 177,068 186,271 Other assets 4,865 1,534 Total assets $ 3,432,180 $ 3,236,934 Liabilities and Shareholders’ Equity Liabilities: Other liabilities $ 5,469 $ 6,378 Other borrowings – Trust preferred debt 7,217 — Subordinated debentures 144,640 — Total liabilities 157,326 6,378 Shareholders’ equity: Common stock 4 4 Capital surplus 1,006,535 982,009 Retained earnings 2,823,334 2,704,121 Treasury stock (544,052 ) (477,165 ) Accumulated other comprehensive income (loss) (10,967 ) 21,587 Total shareholders’ equity 3,274,854 3,230,556 Total liabilities and shareholders’ equity $ 3,432,180 $ 3,236,934 Statements of Earnings (In thousands) Year Ended December 31, 2016 2015 2014 Dividends, interest and fees received from bank subsidiaries $ 15,237 $ 150,308 $ 75,412 Dividends, interest and fees received from non-bank subsidiaries 25,923 — — Other revenue 1,612 1,279 1,572 Total revenue 42,772 151,587 76,984 Interest expense 4,182 131 293 Charitable contributions to BOKF Foundation — — 2,420 Professional fees and services 395 378 600 Other operating expense 1,583 1,864 1,556 Total expense 6,160 2,373 4,869 Income before taxes and equity in undistributed income of subsidiaries 36,612 149,214 72,115 Federal and state income taxes (1,920 ) (375 ) (1,702 ) Income before equity in undistributed income of subsidiaries 38,532 149,589 73,817 Equity in undistributed income of bank subsidiaries 216,120 134,045 214,435 Equity in undistributed income of non-bank subsidiaries (21,984 ) 4,931 4,183 Net income attributable to BOK Financial Corp. shareholders $ 232,668 $ 288,565 $ 292,435 Statements of Cash Flows (In thousands) Year Ended December 31, 2016 2015 2014 Cash Flows From Operating Activities: Net income $ 232,668 $ 288,565 $ 292,435 Adjustments to reconcile net income to net cash provided by operating activities: Equity in undistributed income of bank subsidiaries (216,120 ) (134,045 ) (214,435 ) Equity in undistributed income of non-bank subsidiaries 21,984 (4,931 ) (4,183 ) Tax effect from equity compensation, net (1,505 ) (925 ) (8,258 ) Change in other assets (2,933 ) 49 8,726 Change in other liabilities (1,285 ) (2,818 ) 1,055 Net cash provided by operating activities 32,809 145,895 75,340 Cash Flows From Investing Activities: Proceeds from sales of available for sale securities 1,632 4,760 — Investment in subsidiaries (26,000 ) (41,969 ) (15,336 ) Acquisitions, net of cash acquired (105,520 ) — — Net cash used in investing activities (129,888 ) (37,209 ) (15,336 ) Cash Flows From Financing Activities: Issuance of subordinated debentures, net of issuance costs 144,615 — — Issuance of common and treasury stock, net 12,455 6,711 4,472 Tax effect from equity compensation, net 1,505 925 8,258 Dividends paid (113,455 ) (115,281 ) (111,026 ) Repurchase of common stock (66,792 ) (229,540 ) (12,337 ) Net cash used in financing activities (21,672 ) (337,185 ) (110,633 ) Net decrease in cash and cash equivalents (118,751 ) (228,499 ) (50,629 ) Cash and cash equivalents at beginning of period 282,169 510,668 561,297 Cash and cash equivalents at end of period $ 163,418 $ 282,169 $ 510,668 Cash paid for interest $ 4,127 $ 131 $ 293 Issuance of shares in settlement of deferred compensation, net $ — $ — $ 8,352

Subsequent Events

Subsequent Events	12 Months Ended
	Dec. 31, 2016
Subsequent Events [Abstract]
Subsequent Events [Text Block]	Subsequent Events The Company evaluated events from the date of the consolidated financial statements on December 31, 2016 through the issuance of those consolidated financial statements included in this Annual Report on Form 10-K. No events were identified requiring recognition in and/or disclosure in the consolidated financial statements.

Significant Accounting Polici28

Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2016
Accounting Policies [Abstract]
Basis of Presentation [Policy Text Block]	The Consolidated Financial Statements of BOK Financial Corporation (“BOK Financial” or “the Company”) have been prepared in conformity with accounting principles generally accepted in the United States ("U.S. GAAP"), including interpretations of U.S. GAAP issued by federal banking regulators and general practices of the banking industry.
Consolidation [Policy Text Block]	The consolidated financial statements include the accounts of BOK Financial and its subsidiaries, principally BOKF, NA, BOK Financial Securities, Inc., The Milestone Group, Inc. and Cavanal Hill Investment Management, Inc. All significant intercompany transactions are eliminated in consolidation. The consolidated financial statements include the assets, liabilities, non-controlling interests and results of operations of variable interest entities (“VIEs”) when BOK Financial is determined to be the primary beneficiary. Variable interest entities are generally defined as entities that either do not have sufficient equity to finance their activities without support from other parties or whose equity investors lack a controlling financial interest. See additional discussion of variable interest entities at Note 14 following.
Reclassifications [Text Block]	Certain prior year amounts have been reclassified to conform to the current year presentation. For 2015, $8.4 million of residential mortgage loan origination costs were reclassified from operating expense to mortgage banking revenue. Correction of this error did not affect net income or earnings per share.
Nature of Operations [Text Block]	Nature of Operations BOK Financial, through its subsidiaries, provides a wide range of financial services to commercial and industrial customers, other financial institutions, municipalities, and consumers. These services include depository and cash management; lending and lease financing; mortgage banking; securities brokerage, trading and underwriting; and personal and corporate trust. BOKF, NA operates as Bank of Oklahoma primarily in the Tulsa and Oklahoma City metropolitan areas of the state of Oklahoma and Bank of Texas primarily in the Dallas, Fort Worth and Houston metropolitan areas of the state of Texas. In addition, BOKF, NA does business as Bank of Albuquerque in Albuquerque, New Mexico; Colorado State Bank and Trust in Denver, Colorado; Bank of Arizona in Phoenix, Arizona; Bank of Kansas City and Mobank in Kansas City, Missouri/Kansas and Bank of Arkansas in Northwest Arkansas. BOKF, NA also operates the TransFund electronic funds network.
Use of Estimates [Policy Text Block]	Use of Estimates Preparation of BOK Financial's consolidated financial statements requires management to make estimates of future economic activities, including loan collectability, prepayments and cash flows from customer accounts. These estimates are based upon current conditions and information available to management. Actual results may differ significantly from these estimates.
Acquisitions [Policy Text Block]	Acquisitions Assets and liabilities acquired, including identifiable intangible assets, are recorded at fair value on the acquisition date. The purchase price includes consideration paid at closing and the estimated fair value of contingent consideration that will be paid in the future, subject to achieving defined performance criteria. Premiums and discounts assigned to interest-earning assets and interest-bearing liabilities are amortized over the lives of the acquired assets and liabilities on either an individual instrument or pool basis. Provision for credit losses is recognized for changes in credit quality after the acquisition date. Goodwill is recognized as the excess of the purchase price over the net fair value of assets acquired and liabilities assumed. The Consolidated Statements of Earnings include the results of operations from the acquisition date.
Goodwill and Intangible Assets [Policy Text Block]	Goodwill and Intangible Assets Goodwill and intangible assets generally result from business combinations and are evaluated for each of BOK Financial's reporting units for impairment annually or more frequently if conditions indicate impairment. The evaluation of possible impairment of goodwill and intangible assets involves significant judgment based upon short-term and long-term projections of future performance. Reporting units are defined by the Company as significant lines of business within each operating segment. This definition is consistent with the manner in which the chief operating decision maker assesses the performance of the Company and makes decisions concerning the allocation of resources. The Company qualitatively assesses whether it is more likely than not that the fair value of the reporting units are less than their carrying value, including goodwill. Reporting unit carrying value includes sufficient capital to exceed regulatory requirements. This assessment includes consideration of relevant events and circumstances including but not limited to macroeconomic conditions, industry and market conditions, the financial and stock performance of the Company and other relevant factors. If the Company concludes that it is not more likely than not that the fair value of a reporting unit is less than its carrying value through the qualitative assessment, a quantitative Step 1 analysis is performed. The quantitative analysis compares the fair value of the reporting unit with its carrying value, including goodwill. The fair value of each reporting unit is estimated by the discounted future earnings method. Goodwill is considered impaired if the fair value of the reporting unit is less than the carrying value of the reporting unit, including goodwill. Impairment is measured through a detailed Step 2 assessment of the fair values for each asset and liability assigned to the reporting unit performed in a manner similar to a business combination. Intangible assets are generally composed of customer relationships, naming rights, non-compete agreements and core deposit premiums. They are amortized using accelerated or straight-line methods, as appropriate, over the estimated benefit periods. These periods range from 3 years to 20 years . The net book values of identifiable intangible assets are evaluated for impairment when economic conditions indicate impairment may exist.
Cash and Cash Equivalents [Policy Text Block]	Cash Equivalents Due from banks, funds sold (generally federal funds sold for one day), resell agreements (which generally mature within one to 30 days ) and investments in money market funds are considered cash equivalents.
Securities [Policy Text Block]	Securities Securities are identified as trading, investment (held to maturity) or available for sale at the time of purchase based upon the intent of management, liquidity and capital requirements, regulatory limitations and other relevant factors. Trading securities, which are acquired for profit through resale, are carried at fair value with unrealized gains and losses included in current period earnings. Investment securities are carried at amortized cost. Amortization is computed by methods that approximate level yield and is adjusted for changes in prepayment estimates. Securities identified as available for sale are carried at fair value. Unrealized gains and losses are recorded, net of deferred income taxes, as accumulated other comprehensive income in shareholders' equity. Available for sale securities are separately identified as pledged to creditors if the creditor has the right to sell or re-pledge the collateral. The purchase or sale of securities is recognized on a trade date basis. Realized gains and losses on sales of securities are based upon specific identification of the security sold. A receivable or payable is recognized for subsequent transaction settlement. Securities meeting certain criteria may also be transferred from the available for sale classification to the investment securities portfolio at fair value on the date of transfer. The unrealized gain or loss at the date of transfer is retained in accumulated other comprehensive income and in the carrying value of the investment securities portfolio. Such amounts are amortized over the estimated remaining life of the security as an adjustment to yield, offsetting the related amortization of the premium or accretion of the discount on the transferred securities. On a quarterly basis, the Company performs separate evaluations of impaired debt investment and available for sale securities and equity available for sale securities to determine if the decline in fair value below the amortized cost is other-than-temporary. For debt securities, management determines whether it intends to sell or if it is more likely than not that it will be required to sell impaired securities. This determination considers current and forecasted liquidity requirements and securities portfolio management. If the Company intends to sell or it is more likely than not that it will be required to sell the impaired debt security, a charge is recognized against earnings for the entire unrealized loss. For all impaired debt securities for which there is no intent or expected requirement to sell, the evaluation considers all available evidence to assess whether it is more likely than not that all amounts due would not be collected according to the security's contractual terms. Impairment of debt securities rated investment grade by all nationally-recognized rating agencies is considered temporary unless specific contrary information is identified. Impairment of debt securities rated below investment grade by at least one of the nationally recognized rating agencies is evaluated based on projections of estimated cash flows. Any expected credit loss due to the inability to collect all amounts due according to the security's contractual terms is recognized as a charge against earnings. Any remaining unrealized loss related to other factors would be recognized in other comprehensive income, net of taxes. For equity securities, management evaluates various factors including cause, severity and duration of the decline in value of the security and prospects for recovery, as well as the Company's intent and ability not to sell the security until the fair value exceeds amortized cost over periods not to exceed three years. If an unrealized loss is determined to be other-than-temporary, a charge is recognized against earnings for the difference between the security's amortized cost and fair value. BOK Financial may elect to carry certain securities at fair value with changes in fair value recognized in current period income. These securities are held with the intent that gains or losses will offset changes in the fair value of mortgage servicing rights or certain derivative instruments. Restricted equity securities represent equity interests the Company is required to hold in the Federal Reserve Banks and Federal Home Loan Banks. Restricted equity securities are carried at cost as these securities do not have a readily determined fair value because ownership of these shares is restricted and they lack a market.
Derivatives Instruments [Policy Text Block]	Derivative Instruments Derivative instruments may be used by the Company as part of its internal risk management programs or may be offered to customers. All derivative instruments are carried at fair value and changes in fair value are generally reported in income as they occur. The determination of fair value of derivative instruments considers changes in interest rates, commodity prices and foreign exchange rates. Credit risk is also considered in determining fair value. Deterioration in the credit rating of customers or other counterparties reduces the fair value of asset contracts. Deterioration of our credit rating could decrease the fair value of our derivative liabilities. When bilateral netting agreements or similar agreements exist between the Company and its counterparties that create a single legal claim or obligation to pay or receive the net amount in settlement of the individual derivative contracts, the Company reports derivative assets and liabilities on a net by derivative contract by counterparty basis. Derivative contracts may also require the Company to provide or receive cash margin as collateral for derivative assets and liabilities. Derivative assets and liabilities are reported net of cash margin when certain conditions are met. In addition, derivative contracts executed with customers under Customer Risk Management Programs may be secured by non-cash collateral in conjunction with a credit agreement with that customer. Access to collateral, in the event of default is reasonably assured. Derivative instruments may be designated as cash flow hedges of variable rate assets or liabilities, or of anticipated transactions. Changes in the fair value of derivative instruments designated as cash flow hedges are recorded in accumulated other comprehensive income to the extent they are effective. The amount recorded in other comprehensive income is reclassified to earnings in the same periods as the hedged cash flows impact earnings. The ineffective portion of changes in fair value is reported in current earnings. BOK Financial may use derivative instruments in managing its interest rate sensitivity, as part of its economic hedge of the changes in the fair value of mortgage servicing rights and as an economic hedge of trading securities. Changes in the fair value of derivative instruments used in managing interest rate sensitivity and as part of its economic hedge of changes in the fair value of mortgage servicing rights are included in Other Operating Revenue - Gain (loss) on derivatives, net in the Consolidated Statement of Earnings. Changes in the fair value of derivative instruments used as an economic hedge of trading securities are included in Operating Revenue- Brokerage and trading revenue. BOK Financial also enters into mortgage loan commitments that are considered derivative contracts. Forward sales contracts that have not been designated as hedging instruments are used to economically hedge these mortgage loan commitments as well as mortgage loans held for sale. Mortgage loan commitments are carried at fair value based upon quoted prices. Changes in fair value of mortgage loan commitments, mortgage loans held for sale and forward sales contracts are reported in Other Operating Revenue - Mortgage Banking Revenue. BOK Financial offers programs that permit its customers to manage various risks, including fluctuations in energy, cattle and other agricultural products, interest rates and foreign exchanges rates with derivative contracts. Customers may also manage interest rate risk through interest rate swaps used by the borrower to modify interest rate terms of their loans or to-be-announced securities used by our mortgage banking customers to hedge their loan production. Derivative contracts are executed between the customers and BOK Financial. Offsetting contracts are executed between BOK Financial and other selected counterparties to minimize market risk from changes in commodity prices, interest rates or foreign exchange rates. The counterparty contracts are identical to customer contracts, except for a fixed pricing spread or fee paid to BOK Financial as profit and compensation for administrative costs and credit risk which is recognized over the life of the contracts and included in other Operating Revenue - Brokerage and Trading Revenue in the Consolidated Statements of Earnings.
Loans [Policy Text Block]	Loans Loans are either secured or unsecured based on the type of loan and the financial condition of the borrower. Repayment is generally expected from cash flow or proceeds from the sale of selected assets of the borrower. BOK Financial is exposed to risk of loss on loans due to the borrower's financial difficulties, which may arise from any number of factors, including problems within the respective industry or local economic conditions. Access to collateral, in the event of borrower default, is reasonably assured through adherence to applicable lending laws and through sound lending standards and credit review procedures. Accounting policies for all loans, excluding residential loans guaranteed by U.S. government agencies, are as follows. Interest is accrued at the applicable interest rate on the outstanding principal amount. Loans are placed on nonaccruing status when, in the opinion of management, full collection of principal or interest is uncertain. Internally risk graded loans are individually evaluated for nonaccruing status quarterly. Non-risk graded loans are generally placed on nonaccruing status when 90 days or more past due or within 60 days of being notified of the borrower's bankruptcy filing. Interest previously accrued but not collected is charged against interest income when the loan is placed on nonaccruing status. Payments received on nonaccruing loans are applied to principal or recognized as interest income, according to management's judgment as to the collectability of principal. Loans may be returned to accruing status when, in the opinion of management, full collection of principal and interest, including principal previously charged off, is probable based on improvements in the borrower's financial condition or a sustained period of performance. Loans to borrowers experiencing financial difficulties may be modified in troubled debt restructurings ("TDRs"). All TDRs are classified as nonaccruing. Modifications generally consist of extension of payment terms or interest rate concessions and may result either voluntarily through negotiations with the borrower or involuntarily through court order. Generally, principal and accrued but unpaid interest is not voluntarily forgiven. Performing loans may be renewed under the current collateral, debt service ratio and other underwriting standards. Nonaccruing loans may also be renewed and will remain classified as nonaccruing. Occasionally, loans, other than residential mortgage loans, may be held for sale in order to manage credit concentration. These loans are carried at the lower of cost or fair value with gains or losses recognized in gain (loss) on assets. All loans are charged-off when the loan balance or a portion of the loan balance is no longer supported by the paying capacity of the borrower or when the required cash flow is reduced in a TDR. The charge-off amount is determined through an evaluation of available cash resources and collateral value. Internally risk graded loans are evaluated quarterly and charge-offs are taken in the quarter in which the loss is identified. Non-risk graded loans that are past due between 60 days and 180 days , based on the loan product type, are charged off. Loans to borrowers whose personal obligation has been discharged through Chapter 7 bankruptcy proceedings are charged off within 60 days of notice of the bankruptcy filing, regardless of payment status. Loan origination and commitment fees and direct loan acquisition and origination costs are deferred and amortized as an adjustment to yield over the life of the loan or over the commitment period, as applicable. Amortization does not anticipate loan prepayments. Net unamortized fees are recognized in full at time of payoff. Qualifying residential mortgage loans guaranteed by U.S. government agencies have been sold into GNMA pools. Under certain performance conditions specified in government programs, the Company has the right, but not the obligation to repurchase loans from GNMA pools. These loans no longer qualify for sale accounting and are recognized in the Consolidated Balance Sheet. Guaranteed loans are considered to be impaired because we do not expect to receive all principal and interest based on the loan's contractual terms. The principal balance continues to be guaranteed, however, interest accrues at a curtailed rate as specified in the programs. The carrying value of these loans is reduced based on an estimate of expected cash flows discounted at the original note rate plus a liquidity spread. Guaranteed loans may be modified in TDRs in accordance with U.S. government agency guidelines. Interest continues to accrue at the modified rate. U.S. government guaranteed loans may either be resold into GNMA pools after a performance period specified by the programs or foreclosed and conveyed to the guarantors. Loans are disaggregated into portfolio segments and further disaggregated into classes. The portfolio segment is the level at which the Company develops and documents a systematic method for determining its Allowance for Credits Losses. Classes are based on the risk characteristics of the loans and the Company's method for monitoring and assessing credit risk.
Allowance for Loan Losses and Accrual for Off-Balance Sheet Credit Losses [Policy Text Block]	Allowance for Loan Losses and Accrual for Off-Balance Sheet Credit Risk The appropriateness of the allowance for loan losses and accrual for off-balance sheet credit risk (collectively "Allowance for Credit Losses") is assessed by management quarterly based on an ongoing quarterly evaluation of the probable estimated losses inherent in the portfolio, including probable losses on outstanding loans and unused commitments to provide financing. A consistent well-documented methodology has been developed and is applied by an independent Credit Administration department to assure consistency across the Company. The allowance for loan losses consists of specific allowances attributed to impaired loans that have not yet been charged down to amounts we expect to recover, general allowances based on estimated loss rates by loan class and nonspecific allowances based on factors that affect more than one portfolio segment. There were no changes to the methodology for estimating general allowances during 2016 or 2015 . Loans are considered to be impaired when it becomes probable that BOK Financial will be unable to collect all amounts due according to the contractual terms of the loan agreements. Internally risk graded loans are evaluated individually for impairment. Substantially all commercial and commercial real estate loans and certain residential mortgage and personal loans are risk graded based on a quarterly evaluation of the borrowers' ability to repay. Certain commercial loans and most residential mortgage and personal loans are small balance, homogeneous pools of loans that are not risk graded. Non-risk graded loans are identified as impaired based on performance status. Generally, non-risk graded loans 90 days or more past due, modified in a troubled debt restructuring or in bankruptcy are considered to be impaired. Specific allowances for impaired loans are measured by an evaluation of estimated future cash flows discounted at the loan's initial effective interest rate or the fair value of collateral for certain collateral dependent loans. The fair value of real property held as collateral is generally based on third party appraisals that conform to Uniform Standards of Professional Appraisal Practice, less estimated selling costs. Appraised values are on an “as-is” basis and generally are not adjusted by the Company. Updated appraisals are obtained at least annually or more frequently if market conditions indicate collateral values may have declined. Collateral value of mineral rights is generally determined by our internal staff of engineers based on projected cash flows from proven oil and gas reserves under existing economic and operating conditions. The value of other collateral is generally determined by our special assets staff based on projected liquidation cash flows under current market conditions. Collateral values and available cash resources that support impaired loans are evaluated quarterly. Historical statistics may be used as a practical way to estimate impairment in limited situations, such as when a collateral dependent loan is identified as impaired at the end of a reporting period until an appraisal of collateral value is received or a full assessment of future cash flows is completed. Estimates of future cash flows and collateral values require significant judgments and may be volatile. General allowances for unimpaired loans are based on an estimated loss rate by loan class. The appropriate historical gross loss rate for each loan class is determined by the greater of the current loss rate based on the most recent twelve months or a ten-year average gross loss rate. Recoveries are not directly considered in the estimation of historical loss rates. Recoveries generally do not follow predictable patterns and are not received until well-after the charge-off date as a result of protracted legal actions. For risk graded loans, historical gross loss rates are adjusted for changes in risk grading. For each loan class, the current weighted average risk grade is compared to the long-term weighted average risk grade. This comparison determines whether credit risk in each loan class is increasing or decreasing. Historical loss rates are adjusted upward or downward in proportion to changes in average risk grading. General allowances for unimpaired loans also consider inherent risks identified for each loan class. Inherent risks consider loss rates that most appropriately represent the current credit cycle and other factors attributable to a specific loan class which have not yet been represented in the historical gross loss rates or risk grading. These factors include changes in commodity prices or engineering imprecision which may affect the value of reserves that secure our energy loan portfolio, construction risk that may affect commercial real estate loans, changes in regulations and public policy that may disproportionately impact health care loans and changes in loan products. Nonspecific allowances are maintained for risks beyond factors specific to a particular portfolio segment or loan class. These factors include trends in the economy in our primary lending areas, concentration in large-balance loans and other relevant factors. An accrual for off-balance sheet credit risk is included in Other liabilities. The appropriateness of the accrual is determined in the same manner as the allowance for loan losses. A provision for credit losses is charged against or credited to earnings in amounts necessary to maintain an appropriate Allowance for Credit Losses. Recoveries of loans previously charged off are added to the allowance when received.
Transfers of Financial Assets [Policy Text Block]	Transfers of Financial Assets BOK Financial regularly transfers financial assets as part of its mortgage banking activities and periodically may transfer other financial assets. Transfers are recorded as sales when the criteria for surrender of control are met. The Company has elected to carry certain residential mortgage loans held for sale at fair value under the fair value option. Changes in fair value are recognized in net income as they occur. These loans are reported separately in the Consolidated Balance Sheets and changes in fair value are recorded in other operating revenue - mortgage banking revenue in the Consolidated Statements of Earnings. Fair value of conforming residential mortgage loans that will be sold to U.S. government agencies is based on sales commitments or market quotes considered Level 2 inputs. Fair value of mortgage loans that are unable to be sold to U.S. government agencies is based on Level 3 inputs using quoted prices of loans that are sold in securitization transactions with a liquidity discount applied. The fair value is corroborated with an independent third party on at least an annual basis. BOK Financial retains a repurchase obligation under underwriting representations and warranties related to residential mortgage loans transferred and generally retains the right to service the loans. The Company may incur a recourse obligation in limited circumstances. Separate accruals are recognized in Other liabilities in the Consolidated Balance Sheets for repurchase and recourse obligations. These reserves reflect the estimated amount of probable loss the Company will incur as a result of repurchasing a loan, indemnifications, and other settlement resolutions. Repurchases of loans with an origination defect that are also credit impaired are considered collateral dependent and are initially recognized at net realizable value (appraised value less the cost to sell). The difference between unpaid principal balance and net realizable value is not accreted. Repurchases of loans with an origination defect that are not credit impaired are carried at fair value as of the repurchase date. Interest income continues to accrue on these loans and the discount is accreted over the estimated life of the loan. The accrual for credit losses related to recourse loans for principal and interest is performed by Credit Administration and subject to oversight by the Finance/Credit Administration Allowance Committee. All other mortgage related accruals are reviewed monthly by the Mortgage Contingency Loss Accrual Committee which is subject to oversight by Finance. The Company may also choose to purchase GNMA loans once certain mandated delinquency criteria are met. The loans that are eligible and are chosen to be repurchased are initially recognized at fair value based on expected cash flow discounted using the average agency guaranteed debenture rates, average actual principal loss rates and liquidity premium. The Company may also retain a residual interest in excess cash flows generated by the assets. All assets obtained, including cash, servicing rights and residual interests, and all liabilities incurred, including recourse obligations, are initially recognized at fair value, all assets transferred are de-recognized and any gain or loss on the sale is recognized in earnings. Subsequently, servicing rights and residual interest are carried at fair value with changes in fair value recognized in earnings as they occur.
Real Estate and Other Repossessed Assets [Policy Text Block]	Real Estate and Other Repossessed Assets Real estate and other repossessed assets are acquired in partial or total forgiveness of loans. These assets are initially recognized at cost, which is determined by fair value at date of foreclosure less estimated disposal costs. They are subsequently carried at the lower of cost or current fair value less estimated disposal costs. Decreases in fair value below cost are recognized as asset-specific valuation allowances which may be reversed when supported by future increases in fair value. Subsequent increases in fair value may be used to reduce the allowance but not below zero. Fair values of real estate are based on “as is” appraisals which are updated at least annually or more frequently for certain asset types or assets located in certain distressed markets. Fair values based on appraisals are generally considered to be based on significant other observable inputs. The Company also considers decreases in listing price and other relevant information in quarterly evaluations and reduces the carrying value of real estate and other repossessed assets when necessary. Fair values based on list prices and other relevant information are generally considered to be based on significant unobservable inputs. Additional costs incurred to complete real estate and other repossessed assets may increase the carrying value, up to current fair value based on “as completed” appraisals. The fair value of mineral rights included in repossessed assets are generally determined by our internal staff of engineers based on projected cash flows from proven oil and gas reserves under existing economic and operating conditions. The value of other repossessed assets is generally determined by our special assets staff based on projected liquidation cash flows under current market conditions. Income generated by these assets is recognized as received. Operating expenses are recognized as incurred. Gains or losses on sales of real estate and other repossessed assets are based on the cash proceeds received less the cost basis of the asset, net of any valuation allowances. The estimated disposal costs of real estate and other repossessed assets are evaluated by the Company on an annual basis based on actual results.
Premises and Equipment [Policy Text Block]	Premises and Equipment Premises and equipment are carried at cost, including capitalized interest when appropriate, less accumulated depreciation and amortization. Depreciation and amortization are computed on a straight-line basis over the estimated useful lives of the assets or, for leasehold improvements, over the shorter of the estimated useful lives or remaining lease terms. Useful lives range from 5 years to 40 years for buildings and improvements, 3 years to 10 years for software and 3 years to 10 years for furniture and equipment. Construction in progress represents facilities construction and data processing systems projects underway that have not yet been placed into service. Depreciation and amortization begin once the assets are placed into service. Repair and maintenance costs, including software maintenance and enhancement costs, are charged to expense as incurred. Software licensing costs are generally charged to expense as incurred. Software licensing costs are capitalized if the contractual right to take possession of the software exists and it is feasible to take possession without significant penalty. Capitalized costs are amortized over the shorter of the estimated useful life of the software or remaining contractual life of the license. Premises no longer used by the Company are transferred to real estate and other repossessed assets. The transferred amount is the lower of cost less accumulated depreciation or fair value less estimated disposal costs as of the transfer date. Rent expense for leased premises is recognized as incurred over the lease term. The effects of rent holidays, significant rent escalations and other adjustments to rent payments are recognized on a straight-line basis over the lease term. Ongoing technology projects of significant size or length are reviewed at least annually for impairment. The construction in progress account is reviewed for projects or components of projects that do not support the value of the asset being constructed. Findings of obsolescence, duplicate effort or other conditions that do not support the recorded value are impaired, with the cost of the impaired components being charged to current-year earnings.
Mortgage Servicing Rights [Policy Text Block]	Mortgage Servicing Rights Mortgage servicing rights may be purchased or may be recognized when mortgage loans are originated and sold with servicing right retained. All mortgage servicing rights are carried at fair value. Changes in the fair value are recognized in earnings as they occur. There is no active market for trading in mortgage servicing rights after origination. A cash flow model is used to determine fair value. Key assumptions and estimates, including projected prepayment speeds and assumed servicing costs, earnings on escrow deposits, ancillary income and discount rates, used by this model are based on current market sources. Assumptions used to value mortgage servicing rights are considered significant unobservable inputs. A separate third party model is used to estimate prepayment speeds based on interest rates, housing turnover rates, estimated loan curtailment, anticipated defaults and other relevant factors. The prepayment model is updated daily for changes in market conditions and adjusted to better correlate with actual performance of BOK Financial's servicing portfolio. Fair value estimates from outside sources are received at least annually to corroborate the results of the valuation model.
Federal and State Income Taxes [Policy Text Block]	Federal and State Income Taxes BOK Financial and its subsidiaries file consolidated tax returns. The subsidiaries provide for income taxes on a separate return basis and remit to BOK Financial amounts determined to be currently payable. BOK Financial is agent for its subsidiaries under the Company's tax sharing agreements and has no ownership rights to any refunds received for the benefit of its subsidiaries. Current income tax expense or benefit is based on an evaluation that considers estimated taxable income, tax credits, and statutory federal and state income tax rates. The amount of current income tax expense or benefit recognized in any period may differ from amounts reported to taxing authorities. Annually, tax returns are filed with each jurisdiction where the Company conducts business and recognized current income tax expense or benefit is adjusted to the filed tax returns. Deferred tax assets and liabilities are based upon the differences between the values of assets and liabilities as recognized in the financial statements and their related tax basis using enacted tax rates in effect for the year in which the differences are expected to be recovered or settled. A valuation allowance is provided when it is more likely than not that some portion of the entire deferred tax asset may not be realized based on taxes previously paid in net loss carry-back periods and other factors. BOK Financial has unrecognized tax benefits, which are included in accrued current income taxes payable, for the uncertain portion of recorded tax benefits and related interest. These uncertainties result from the application of complex tax laws, rules, regulations and interpretations, primarily in state taxing jurisdictions. Unrecognized tax benefits are assessed quarterly and may be adjusted through current income tax expense in future periods based on changing facts and circumstances, completion of examinations by taxing authorities or expiration of a statute of limitations. Estimated penalties and interest on uncertain tax positions are recognized in income tax expense.
Employee Benefit Plans [Policy Text Block]	Employee Benefit Plans BOK Financial sponsors a defined benefit cash balance pension plan (“Pension Plan”), qualified profit sharing plan (“Thrift Plan”) and employee health care plans. Pension Plan costs, which are based upon actuarial computations of current costs, are expensed annually. Unrecognized prior service cost and net gains or losses are amortized on a straight-line basis over a period not to exceed the average remaining service periods of the participants. Employer contributions to the Pension Plan are in accordance with Federal income tax regulations. Pension Plan benefits were curtailed as of April 1, 2006. No participants may be added to the Pension Plan and no additional service benefits will be accrued. BOK Financial recognizes the funded status of its employee benefit plans. For a pension plan, the funded status is the difference between the fair value of plan assets and the projected benefit obligation measured as of the fiscal year-end date. Adjustments required to recognize the Pension Plan's net funded status are made through accumulated other comprehensive income, net of deferred income taxes. Employer contributions to the Thrift Plan, which matches employee contributions subject to percentage and years of service limits, are expensed when incurred. BOK Financial recognizes the expense of health care benefits on the accrual method.
Shared-Based Compensation Plans [Policy Text Block]	Share-Based Compensation Plans BOK Financial awards stock options and non-vested common shares as compensation to certain officers. Compensation cost is generally fixed based on the grant date fair value of the award. The grant date fair value of stock options is based on the Black-Scholes option pricing model. Stock options generally have graded vesting over 7 years . Each tranche is considered a separate award for valuation and compensation cost recognition. Grant date fair value of non-vested shares is based on the then-current market value of BOK Financial common stock. Non-vested shares awarded prior to 2013 generally cliff vest in 5 years . Non-vested shares awarded since January 1, 2013 generally cliff vest in 3 years and are subject to a two year holding period after vesting. Shares awarded under the Executive Incentive Plan are subject to downward adjustment at the discretion of the Incentive Compensation Committee. Compensation cost of non-vested shares granted under the Executive Incentive Plan varies based on changes in the fair value of BOKF common shares. Compensation cost is recognized as expense over the service period, which is generally the vesting period. Expense is reduced for estimated forfeitures over the vesting period and adjusted for actual forfeitures as they occur. Stock-based compensation awarded to certain officers has performance conditions that affect the number of awards granted. Compensation cost is adjusted based on the probable outcome of the performance conditions. Excess tax benefits from share-based payments recognized in capital surplus are determined by the excess of tax benefits recognized over the tax effect of compensation cost recognized. Dividends on non-vested shares that are not subject to forfeiture are charged to dividends paid.
Other Operating Revenue [Policy Text Block]	Other Operating Revenue Fees and commission revenue is recognized at the time the related services are provided or products are sold and may be accrued when necessary. Accrued fees and commissions are reversed against revenue if amounts are subsequently deemed to be uncollectible. Revenue is recognized on a gross basis whenever we have primary responsibility and risk in providing the services or products to our customers and on a net basis whenever we act as a broker for products or services of others. Brokerage and trading revenue includes changes in the fair value of securities and derivatives held for trading purposes and derivatives held for customer risk management programs, including credit losses, commissions earned from the retail sale of securities, mutual funds and other financial instruments, and underwriting and financial advisory fees. Transaction card revenue includes merchant discount fees, electronic funds transfer network fees and check card fees. Merchant discount fees represent fees paid by customers for account management and electronic processing of transactions. Merchant discount fees are recognized at the time the customer's transactions are processed or other services are performed. The Company also maintains the TransFund electronic funds transfer network for the benefit of its members, which includes BOKF, NA. Electronic funds transfer fees are recognized as electronic transactions processed on behalf of its members. Check card fees represent interchange fees paid by a merchant bank for transactions processed from cards issued by the Company. Check card fees are recognized when transactions are processed. Interchange fees are generally recognized on a gross basis. Related expenses are generally recognized as Data processing and communications expense. Fiduciary and asset management revenue includes fees from asset management, custody, recordkeeping, investment advisory and administration services. Revenue is recognized on an accrual basis at the time the services are performed and may be based on either the fair value of the account or the service provided. Deposit service charges and fees are recognized at least quarterly in accordance with a published deposit account agreements and disclosure statements for retail accounts or contractual agreements for commercial accounts. Item charges for overdraft or non-sufficient funds items are recognized as items are presented for payment. Account balance charges and activity fees are accrued monthly and collected in arrears. Commercial account activity fees may be offset by an earnings credit based on account balances.
Newly Adopted and Pending Accounting Pronouncements [Policy Text Block]	Newly Adopted and Pending Accounting Pronouncements The following is a summary of newly adopted and pending accounting pronouncements that may have a more than insignificant effect on the Company's financial statements. Financial Accounting Standards Board ("FASB") FASB Accounting Standards Update No. 2014-09, Revenue from Contracts with Customers ("ASU 2014-09") On May 28, 2014, the FASB issued ASU 2014-09 to clarify the principles for recognizing revenue by providing a more robust framework that will give greater consistency and comparability in revenue recognition practices. In the new framework, an entity recognizes revenue in an amount that reflects the consideration to which the entity expects to be entitled in exchange for goods or services. The new model requires the identification of performance obligations included in contracts with customers, a determination of the transaction price and an allocation of the price to those performance obligations. The entity recognizes revenue when performance obligations are satisfied. ASU 2014-09 is effective for the Company for annual reporting periods beginning after December 15, 2017, including interim periods within that reporting period. Net interest revenue from financial assets and liabilities is explicitly excluded from the scope of ASU 2014-09. Management expects that most fees and commission revenue will not be affected. The Company continues to evaluate the impact of ASU 2014-09 on Fiduciary and Asset Management Revenue and Transaction Card Revenue which represent 18% of total gross revenue and 39% of fees and commissions revenue for 2016. Timing of revenue recognition and gross vs. net revenue presentation may be affected. Management expects to adopt the standard in the first quarter of 2018 with a cumulative effect adjustment to opening retained earnings if such adjustment is significant. FASB Accounting Standards Update No. 2016-08, Revenue from Contracts with Customers (Topic 606): Principal versus Agent Considerations (Reporting Revenue Gross versus Net) ("ASU 2016-08") On March 17, 2016, the FASB Issued ASU 2016-08 to amend the principal versus agent implementation guidance in ASU 2014-09. The ASU clarifies that an entity should evaluate whether it is the principal or the agent for each specified good or service promised in a contract with a customer. ASU 2016-08 is effective for the Company for annual reporting periods beginning after December 15, 2017, including interim periods within that reporting period. The Company generally follows the guidance of ASU 2016-08 and is evaluating the impact the adoption of ASU 2016-08 may have on the Company's financial statements along with ASU 2014-09. FASB Accounting Standards Update No. 2016-10, Revenue from Contracts with Customers (Topic 606): Identifying Performance Obligations and Licensing ("ASU 2016-10") On April 14, 2016, the FASB issued ASU 2016-10 which amends certain sections of ASU 2014-09 related to identifying performance obligations and licensing implementation. ASU 2016-10 is effective for the Company for annual reporting periods beginning after December 15, 2017, including interim periods within that reporting period. The Company is evaluating the impact the adoption of ASU 2016-10 may have on the Company's financial statements along with ASU 2014-09. FASB Accounting Standards Update No. 2016-12, Revenue from Contracts with Customers (Topic 606): Narrow-Scope Improvements and Practical Expedients ("ASU 2016-12") On May 9, 2016, the FASB issued ASU 2016-12, which amends certain aspects of the Board's new revenue standard, ASU 2014-09. The amendments clarify information regarding collectibility, presentation of sales tax and other similar taxes collected from customers, noncash consideration, contract modifications and completed contracts at transition, and transition disclosures. ASU 2016-12 is effective for the Company for annual reporting periods beginning after December 15, 2017, including interim periods within that reporting period. The Company is evaluating the impact the adoption of ASU 2016-12 may have on the Company's financial statements along with ASU 2014-09. FASB Accounting Standards Update No. 2014-16, Derivatives and Hedging (Topic 815): Determining Whether the Host Contract in a Hybrid Financial Instrument Issued in the Form of a Share is More Akin to Debt or to Equity ("ASU 2014-16") On November 3, 2014, the FASB issued ASU 2014-16 to eliminate the use of different methods and reduce diversity under GAAP in the accounting for hybrid financial instruments issued in the form of a share. For hybrid financial instruments issued in the form of a share, an entity should determine the nature of the host contract by considering all stated and implied substantive terms and features of the hybrid financial instrument. The entity should determine the nature of the host contract by considering the economic characteristics and risks of the entire hybrid financial instrument, including the embedded derivative feature that is being evaluated for separate accounting from the host contract. For public business entities, the ASU was effective for annual periods beginning after December 15, 2015, and interim periods within those annual periods. Adoption of ASU 2014-16 did not impact the Company's consolidated financial statements. FASB Accounting Standards Update No. 2015-02, Consolidation (Topic 810): Amendments to the Consolidation Analysis ("ASU 2015-02") On February 18, 2015, the FASB issued ASU 2015-02 to address concerns that current U.S. GAAP may require a reporting entity to consolidate another legal entity where the reporting entity's contractual rights do not give it the ability to act primarily on its own behalf, the reporting entity does not hold a majority of the legal entity's voting rights, or the reporting entity is not exposed to a majority of the legal entity's economic benefits or obligations. The amendments affected limited partnerships and similar legal entities, the evaluation of fees paid to a decision maker or a service provider as a variable interest, the effect of fee arrangements and related parties on the primary beneficiary determination, and certain investment funds. The ASU was effective for periods beginning after December 15, 2015 for public companies. Adoption of ASU 2015-02 did not have a material impact on the Company's consolidated financial statements. FASB Accounting Standards Update No. 2015-07, Fair Value Measurements (Topic 820): Disclosures for Investments in Certain Entities That Calculate Net Asset Value per Share (or Its Equivalent) ("ASU 2015-07") On May 1, 2015, the FASB issued ASU 2015-07 to gain consistency within the categorization of the fair value hierarchy. The update removed the requirement to categorize within the fair value hierarchy all investments for which fair value is measured using the net asset value per share practical expedient. It also removed the requirement to make certain disclosures for all investments that are eligible to be measured at fair value using the net asset value per share practical expedient. The ASU was effective for the Company for interim and annual periods beginning after December 15, 2015 and was applied retrospectively to all periods presented. Adoption of ASU 2015-07 did not have a material impact on the Company's consolidated financial statements. FASB Accounting Standards Update No. 2016-01, Financial Instruments - Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities ("ASU 2016-01") On January 5, 2016, the FASB issued ASU 2016-01 which requires equity investments, in general, to be measured at fair value with changes in fair value recognized in earnings. It also eliminates the requirement to disclose the methods and significant assumptions used to estimate the fair value for financial instruments measured at amortized cost, requires entities to use the exit price notion when measuring fair value, requires an entity to present separately in other comprehensive income the portion of the total change in fair value of a liability resulting from a change in the instrument-specific credit risk when the fair value option has been elected, requires separate presentation of financial assets and liabilities by measurement category and form on the balance sheet or accompanying notes, clarifies that an entity should evaluate the need for a valuation allowance on a deferred tax asset related to available-for-sale securities in combination with the entity's other deferred tax assets, and simplifies the impairment assessment of equity investments without readily determinable fair values. The ASU is effective for the Company for interim and annual periods beginning after December 15, 2017. Upon adoption, unrealized gains and losses from equity securities will be reclassified from other comprehensive income to retained earnings. As of December 31, 2016, the Company had $2.4 million of net unrealized gains and losses from equity securities in other comprehensive income. FASB Accounting Standards Update No. 2016-02, Leases (Topic 842) ("ASU 2016-02") On February 25, 2016, the FASB issued ASU 2016-02 to increase transparency and comparability by recognizing substantially all lease liabilities on the balance sheet and disclosing key information about leasing arrangements. Lessees will be required to recognize an obligation for future lease payments measured on a discounted basis and a related right-of-use asset. The ASU is effective for the Company for interim and annual periods beginning after December 15, 2018 and requires transition through a modified retrospective approach for leases existing at or entered into after January 1, 2017. The Company is evaluating the impact the adoption of ASU 2016-02 will have on the Company's financial statements. FASB Accounting Standards Update No. 2016-05, Derivatives and Hedging (Topic 815): Effect of Derivative Contract Novations on Existing Hedge Accounting Relationships ("ASU 2016-05") On March 10, 2016, the FASB issued ASU 2016-05 which clarifies that "a change in the counterparty to a derivative instrument that has been designated as the hedging instrument in an existing hedging relationship would not, in and of itself, be considered a termination of the derivative instrument" or "a change in a critical term of the hedging relationship." If all other hedge accounting criteria in ASC 815 are met, a hedging relationship where the hedging derivative instrument is novated would not be discontinued or need to be re-designated. The ASU is effective for interim and annual periods beginning after December 15, 2016. An entity would apply the guidance prospectively unless modified retrospective transition is elected. Early adoption is permitted. Adoption of ASU 2016-05 did not have a material impact on the Company's financial statements. FASB Accounting Standards Update No. 2016-07, Investments - Equity Method and Joint Ventures ("ASU 2016-07") On March 15, 2016, the FASB issued ASU 2016-07 to simplify the equity method of accounting by eliminating the requirement to retrospectively apply the equity method to an investment that subsequently qualifies for such accounting. The ASU also requires that unrealized holding gains or losses in accumulated other comprehensive income related to an available for sale security that becomes eligible for the equity method be recognized in earnings as of the date the investment qualifies for the equity method. The ASU was effective for all entities for fiscal years beginning after December 15, 2016, including interim periods within those fiscal years. Adoption of ASU 2016-07 did not have a material impact on the Company's financial statements. FASB Accounting Standards Update No. 2016-09, Compensation - Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting ("ASU 2016-09") On March 30, 2016, the FASB issued ASU 2016-09 to simplify multiple aspects of accounting for employee share-based payment transactions including accounting income taxes, forfeitures, and statutory tax withholding requirements. The ASU is effective for annual reporting periods beginning after December 15, 2016, including interim periods within those annual reporting periods. Implementation of ASU 2016-09 will add volatility to tax expense as stock prices change; however, we expect the impact on future periods to be insignificant. FASB Accounting Standards Update No. 2016-13, Financial Instruments - Credit Losses (Topic 326): Assets Measured at Amortized Cost ("ASU 2016-13") On June 16, 2016, the FASB issued ASU 2016-13 to provide more timely recording of credit losses on loans and other financial instruments. The ASU requires an impairment model (known as the current expected credit loss ("CECL") model) that is based on expected credit losses rather than incurred credit losses. It requires measurement of all expected credit losses for financial assets carried at amortized cost, including loans and investment securities, based on historical experience, current conditions, and reasonable and supportable forecasts. ASU 2016-13 also changes the recognition of other-than-temporary impairment of available for sale securities to an allowance methodology from an direct write-down methodology. ASU 2016-13 will be effective for the Company for annual reporting periods beginning after December 15, 2019, including interim periods within those fiscal years. Early adoption is permitted for annual reporting periods beginning after December 15, 2018. ASU 2016-13 will be applied through a cumulative-effect adjustment to retained earnings as of the beginning of the first reporting period in which the guidance is effective. The Company is evaluating the impact the adoption of ASU 2016-13 will have on the Company's financial statements. FASB Accounting Standards Update No. 2016-15, Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments ("ASU 2016-15") On August 26, 2016, the FASB issued ASU 2016-15, which amends ASC 230 on the classification of certain cash receipts and payments in the statement of cash flows. The amendments address eight specific cash flow issues. ASU 2016-15 is effective for the Company for annual reporting periods beginning after December 15, 2017, including interim periods within those fiscal years. Entities generally must apply the guidance retrospectively to all periods presented. Adoption of ASU 2016-15 is not expected to have a material impact on the Company's financial statements. FASB Accounting Standards Update No. 2016-17, Consolidation (Topic 810): Interests Held through Related Parties that are under Common Control ("ASU 2016-17") On October 26, 2016, the FASB issued ASU 2016-17, which amends consolidation guidance on related parties under common control. The ASU requires that a single decision maker consider indirect interests held by related parties under common control on a proportionate basis in a manner consistent with its evaluation of indirect interests held through other related parties. ASU 2016-17 was effective for the Company for annual reporting periods beginning after December 15, 2016, including interim and annual periods. Adoption of ASU 2016-17 did not have a material impact on the Company's financial statements.

Reclassifications (Policies)

Reclassifications (Policies)	12 Months Ended
	Dec. 31, 2016
Accounting Policies [Abstract]
Reclassifications [Text Block]	Certain prior year amounts have been reclassified to conform to the current year presentation. For 2015, $8.4 million of residential mortgage loan origination costs were reclassified from operating expense to mortgage banking revenue. Correction of this error did not affect net income or earnings per share.

Securities (Tables)

Securities (Tables)	12 Months Ended
	Dec. 31, 2016
Marketable Securities [Abstract]
Trading Securities [Table Text Block]	The fair value and net unrealized gain (loss) included in trading securities is as follows (in thousands): December 31, 2016 December 31, 2015 Fair Value Net Unrealized Gain (Loss) Fair Value Net Unrealized Gain (Loss) U.S. government agency debentures $ 6,234 $ (4 ) $ 61,295 $ (71 ) U.S. government agency residential mortgage-backed securities 310,067 635 10,989 17 Municipal and other tax-exempt securities 14,427 50 31,901 210 Other trading securities 6,900 57 18,219 (16 ) Total trading securities $ 337,628 $ 738 $ 122,404 $ 140
Investment Securities (Held-to-Maturity) [Table Text Block]	The amortized cost and fair values of investment securities are as follows (in thousands): December 31, 2016 Amortized Carrying Fair Gross Unrealized 1 Cost Value Value Gain Loss Municipal and other tax-exempt securities $ 320,364 $ 320,364 $ 321,225 $ 2,272 $ (1,411 ) U.S. government agency residential mortgage-backed securities – Other 20,777 20,777 21,473 767 (71 ) Other debt securities 205,004 205,004 222,795 18,115 (324 ) Total investment securities $ 546,145 $ 546,145 $ 565,493 $ 21,154 $ (1,806 ) 1 Gross unrealized gains and losses are not recognized in AOCI in the Consolidated Balance Sheets. December 31, 2015 Amortized Carrying Fair Gross Unrealized 1 Cost Value Value Gain Loss Municipal and other tax-exempt securities $ 365,258 $ 365,258 $ 368,910 $ 3,935 $ (283 ) U.S. government agency residential mortgage-backed securities – Other 26,721 26,833 27,874 1,063 (22 ) Other debt securities 205,745 205,745 232,375 26,689 (59 ) Total investment securities $ 597,724 $ 597,836 $ 629,159 $ 31,687 $ (364 ) 1 Gross unrealized gains and losses are not recognized in AOCI in the Consolidated Balance Sheets. The amortized cost and fair values of investment securities at December 31, 2016 , by contractual maturity, are as shown in the following table (dollars in thousands): Less than One Year One to Five Years Six to Ten Years Over Ten Years Total Weighted Average Maturity² Municipal and other tax-exempt securities: Carrying value $ 83,583 $ 181,596 $ 5,909 $ 49,276 $ 320,364 3.41 Fair value 83,544 180,993 5,836 50,852 321,225 Nominal yield¹ 1.48 % 2.08 % 3.31 % 5.20 % 2.43 % Other debt securities: Carrying value $ 16,045 $ 41,804 $ 127,320 $ 19,835 $ 205,004 6.66 Fair value 16,107 44,372 142,010 20,306 222,795 Nominal yield 3.28 % 5.14 % 5.86 % 4.79 % 5.41 % Total fixed maturity securities: Carrying value $ 99,628 $ 223,400 $ 133,229 $ 69,111 $ 525,368 4.68 Fair value 99,651 225,365 147,846 71,158 544,020 Nominal yield 1.77 % 2.65 % 5.75 % 5.08 % 3.59 % Residential mortgage-backed securities: Carrying value $ 20,777 ³ Fair value 21,473 Nominal yield 4 2.76 % Total investment securities: Carrying value $ 546,145 Fair value 565,493 Nominal yield 3.56 % 1 Calculated on a taxable equivalent basis using a 39% effective tax rate. 2 Expected maturities may differ from contractual maturities because borrowers may have the right to call or prepay obligations with or without penalty. 3 The average expected lives of residential mortgage-backed securities were 4.7 years based upon current prepayment assumptions. 4 The nominal yield on residential mortgage-backed securities is based upon prepayment assumptions at the purchase date. Actual yields earned may differ significantly based upon actual prepayments. See Quarterly Financial Summary - Unaudited for current yields on the investment securities portfolio.
Available For Sale Securities [Table Text Block]	The amortized cost and fair value of available for sale securities are as follows (in thousands): December 31, 2016 Amortized Fair Gross Unrealized 1 Cost Value Gain Loss OTTI ² U.S. Treasury securities $ 1,000 $ 999 $ — $ (1 ) $ — Municipal and other tax-exempt securities 41,050 40,993 343 (400 ) — Residential mortgage-backed securities: U.S. government agencies: FNMA 3,062,525 3,055,676 25,066 (31,915 ) — FHLMC 1,534,451 1,531,116 8,475 (11,810 ) — GNMA 878,375 873,594 2,259 (7,040 ) — Total U.S. government agencies 5,475,351 5,460,386 35,800 (50,765 ) — Private issue: Alt-A loans 44,245 51,512 7,485 — (218 ) Jumbo-A loans 56,947 64,023 7,092 (16 ) — Total private issue 101,192 115,535 14,577 (16 ) (218 ) Total residential mortgage-backed securities 5,576,543 5,575,921 50,377 (50,781 ) (218 ) Commercial mortgage-backed securities guaranteed by U.S. government agencies 3,035,750 3,017,933 5,472 (23,289 ) — Other debt securities 4,400 4,152 — (248 ) — Perpetual preferred stock 15,561 18,474 2,913 — — Equity securities and mutual funds 17,424 18,357 1,060 (127 ) — Total available for sale securities $ 8,691,728 $ 8,676,829 $ 60,165 $ (74,846 ) $ (218 ) 1 Gross unrealized gain/loss recognized in AOCI in the consolidated balance sheet. 2 Amounts represent unrealized loss that remains in AOCI after an other-than-temporary credit loss has been recognized in income. December 31, 2015 Amortized Fair Gross Unrealized¹ Cost Value Gain Loss OTTI ² U.S. Treasury securities $ 1,000 $ 995 $ — $ (5 ) $ — Municipal and other tax-exempt securities 56,681 56,817 873 (737 ) — Residential mortgage-backed securities: U.S. government agencies: FNMA 3,156,214 3,187,215 41,502 (10,501 ) — FHLMC 1,940,915 1,949,335 14,727 (6,307 ) — GNMA 763,967 761,801 2,385 (4,551 ) — Total U.S. government agencies 5,861,096 5,898,351 58,614 (21,359 ) — Private issue: Alt-A loans 56,387 62,574 6,574 — (387 ) Jumbo-A loans 71,724 76,544 5,260 — (440 ) Total private issue 128,111 139,118 11,834 — (827 ) Total residential mortgage-backed securities 5,989,207 6,037,469 70,448 (21,359 ) (827 ) Commercial mortgage-backed securities guaranteed by U.S. government agencies 2,919,044 2,905,796 5,396 (18,644 ) — Other debt securities 4,400 4,151 — (249 ) — Perpetual preferred stock 17,171 19,672 2,501 — — Equity securities and mutual funds 17,121 17,833 752 (40 ) — Total available for sale securities $ 9,004,624 $ 9,042,733 $ 79,970 $ (41,034 ) $ (827 ) 1 Gross unrealized gain/loss recognized in AOCI in the consolidated balance sheet. 2 Amounts represent unrealized loss that remains in AOCI after an other-than-temporary credit loss has been recognized in income. The amortized cost and fair values of available for sale securities at December 31, 2016 , by contractual maturity, are as shown in the following table (dollars in thousands): Less than One Year One to Five Years Six to Ten Years Over Ten Years Total Weighted Average Maturity 5 U.S. Treasury securities: Amortized cost $ — $ 1,000 $ — $ — $ 1,000 1.04 Fair value — 999 — — 999 Nominal yield — % 0.87 % — % — % 0.87 % Municipal and other tax-exempt securities: Amortized cost 9,848 12,254 2,103 16,845 41,050 7.95 Fair value 9,903 12,399 2,151 16,540 40,993 Nominal yield¹ 4.81 % 4.01 % 3.47 % 2.28 % 6 3.46 % Commercial mortgage-backed securities: Amortized cost 31,910 921,981 1,832,535 249,324 3,035,750 6.90 Fair value 31,856 920,108 1,820,627 245,342 3,017,933 Nominal yield 1.00 % 1.79 % 1.85 % 1.82 % 1.81 % Other debt securities: Amortized cost — — — 4,400 4,400 30.66 Fair value — — — 4,152 4,152 Nominal yield — % — % — % 1.71 % 1.71 % Total fixed maturity securities: Amortized cost $ 41,758 $ 935,235 $ 1,834,638 $ 270,569 $ 3,082,200 6.95 Fair value 41,759 933,506 1,822,778 266,034 3,064,077 Nominal yield 1.89 % 1.82 % 1.85 % 1.84 % 1.83 % Residential mortgage-backed securities: Amortized cost $ 5,576,543 2 Fair value 5,575,921 Nominal yield 4 1.86 % Perpetual preferred stock. equity securities and mutual funds: Amortized cost $ 32,985 ³ Fair value 36,831 Nominal yield — % Total available-for-sale securities: Amortized cost $ 8,691,728 Fair value 8,676,829 Nominal yield 1.84 % 1 Calculated on a taxable equivalent basis using a 39% effective tax rate. 2 The average expected lives of mortgage-backed securities were 3.9 years based upon current prepayment assumptions. 3 Primarily common stock and preferred stock of corporate issuers with no stated maturity. 4 The nominal yield on mortgage-backed securities is based upon prepayment assumptions at the purchase date. Actual yields earned may differ significantly based upon actual prepayments. See Quarterly Financial Summary –– Unaudited following for current yields on available for sale securities portfolio. 5 Expected maturities may differ from contractual maturities, because borrowers may have the right to call or prepay obligations with or without penalty. 6 Nominal yield on municipal and other tax-exempt securities and other debt securities with contractual maturity dates over ten years are based on variable rates which generally are reset within 35 days . Sales of available for sale securities resulted in gains and losses as follows (in thousands): Year Ended December 31, 2016 2015 2014 Proceeds $ 899,381 $ 1,600,380 2,664,740 Gross realized gains 11,696 15,849 24,923 Gross realized losses (21 ) (3,791 ) (23,384 ) Related federal and state income tax expense 4,542 4,691 599
Securities Pledged As Collateral [Table Text Block]	A summary of investment and available for sale securities that have been pledged as collateral for repurchase agreements, public trust funds on deposit and for other purposes, as required by law was as follows (in thousands): December 31, 2016 2015 Investment: Carrying value $ 322,208 $ 231,033 Fair value 323,808 234,382 Available for sale: Amortized cost 7,353,116 6,831,743 Fair value 7,327,470 6,849,524
Schedule of Unrealized Loss on Investments [Table Text Block]	Temporarily Impaired Securities as of December 31, 2016 (In thousands) Number of Securities Less Than 12 Months 12 Months or Longer Total Fair Value Unrealized Loss Fair Value Unrealized Loss Fair Value Unrealized Loss Investment: Municipal and other tax-exempt securities 151 $ 219,892 $ 1,316 $ 4,333 $ 95 $ 224,225 $ 1,411 U.S. government agency residential mortgage-backed securities – Other 1 4,358 71 — — 4,358 71 Other debt securities 41 11,820 322 855 2 12,675 324 Total investment securities 193 $ 236,070 $ 1,709 $ 5,188 $ 97 $ 241,258 $ 1,806 Number of Securities Less Than 12 Months 12 Months or Longer Total Fair Value Unrealized Loss Fair Value Unrealized Loss Fair Value Unrealized Loss Available for sale: U.S. Treasury securities 1 $ 999 $ 1 $ — $ — $ 999 $ 1 Municipal and other tax-exempt securities 24 $ 15,666 $ 22 $ 4,689 $ 378 20,355 400 Residential mortgage-backed securities: U.S. government agencies: FNMA 91 1,787,644 30,238 72,105 1,677 1,859,749 31,915 FHLMC 58 964,017 11,210 18,307 600 982,324 11,810 GNMA 31 548,637 6,145 25,796 895 574,433 7,040 Total U.S. agencies 180 3,300,298 47,593 116,208 3,172 3,416,506 50,765 Private issue 1 : Alt-A loans 5 7,931 174 7,410 44 15,341 218 Jumbo-A loans 1 — — 6,098 16 6,098 16 Total private issue 6 7,931 174 13,508 60 21,439 234 Total residential mortgage-backed securities 186 3,308,229 47,767 129,716 3,232 3,437,945 50,999 Commercial mortgage-backed securities guaranteed by U.S. government agencies 171 1,904,584 22,987 38,875 302 1,943,459 23,289 Other debt securities 2 — — 4,152 248 4,152 248 Perpetual preferred stock — — — — — — — Equity securities and mutual funds 104 2,127 41 817 86 2,944 127 Total available for sale securities 488 $ 5,231,605 $ 70,818 $ 178,249 $ 4,246 $ 5,409,854 $ 75,064 1 Includes securities for which an unrealized loss remains in AOCI after an other-than-temporary credit loss has been recognized in income. Temporarily Impaired Securities as of December 31, 2015 (In thousands) Number of Securities Less Than 12 Months 12 Months or Longer Total Fair Value Unrealized Loss Fair Value Unrealized Loss Fair Value Unrealized Loss Investment: Municipal and other tax- exempt securities 73 $ 127,319 $ 206 $ 13,380 $ 77 $ 140,699 $ 283 U.S. government agency residential mortgage-backed securities – Other 1 5,533 22 — — 5,533 22 Other debt securities 11 1,082 41 1,715 18 2,797 59 Total investment securities 85 $ 133,934 $ 269 $ 15,095 $ 95 $ 149,029 $ 364 Number of Securities Less Than 12 Months 12 Months or Longer Total Fair Value Unrealized Loss Fair Value Unrealized Loss Fair Value Unrealized Loss Available for sale: U.S. Treasury securities 1 $ 995 $ 5 $ — $ — $ 995 $ 5 Municipal and other tax-exempt securities 20 $ 9,909 $ 27 $ 11,664 $ 710 21,573 737 Residential mortgage-backed securities: U. S. government agencies: FNMA 55 1,188,022 10,262 18,236 239 1,206,258 10,501 FHLMC 40 726,713 4,827 77,545 1,480 804,258 6,307 GNMA 15 364,919 1,951 102,109 2,600 467,028 4,551 Total U.S. agencies 110 2,279,654 17,040 197,890 4,319 2,477,544 21,359 Private issue 1 : Alt-A loans 4 — — 9,264 387 9,264 387 Jumbo-A loans 8 — — 8,482 440 8,482 440 Total private issue 12 — — 17,746 827 17,746 827 Total residential mortgage-backed securities 122 2,279,654 17,040 215,636 5,146 2,495,290 22,186 Commercial mortgage-backed securities guaranteed by U.S. government agencies 213 1,582,469 11,419 484,258 7,225 2,066,727 18,644 Other debt securities 2 — — 4,151 249 4,151 249 Perpetual preferred stock — — — — — — — Equity securities and mutual funds 61 782 5 991 35 1,773 40 Total available for sale securities 419 $ 3,873,809 $ 28,496 $ 716,700 $ 13,365 $ 4,590,509 $ 41,861 1 Includes securities for which an unrealized loss remains in AOCI after an other-than-temporary credit loss has been recognized in income.
Schedule of Investments by Lowest Current Credit Rating [Table Text Block]	At December 31, 2016 , the composition of the Company’s investment and available for sale securities portfolios by the lowest current credit rating assigned by any of the three nationally-recognized rating agencies is as follows (in thousands): AAA - AA A - BBB Below Investment Grade Not Rated Total Carrying Value Fair Value Carrying Value Fair Value Carrying Value Fair Value Carrying Value Fair Value Carrying Value Fair Value Investment: Municipal and other tax-exempt $ 193,931 $ 193,834 $ 6,028 $ 6,037 $ — $ — $ 120,405 $ 121,354 $ 320,364 $ 321,225 U.S. government agency residential mortgage-backed securities 1 — — — — — — 20,777 21,473 20,777 21,473 Other debt securities 140,184 156,641 — — — — 64,820 66,154 205,004 222,795 Total investment securities $ 334,115 $ 350,475 $ 6,028 $ 6,037 $ — $ — $ 206,002 $ 208,981 $ 546,145 $ 565,493 AAA - AA A - BBB Below Investment Grade Not Rated Total Amortized Cost Fair Value Amortized Cost Fair Value Amortized Cost Fair Value Amortized Cost Fair Value Amortized Cost Fair Value Available for Sale: U.S. Treasury securities $ — $ — $ — $ — $ — $ — $ 1,000 $ 999 $ 1,000 $ 999 Municipal and other tax-exempt 23,343 23,657 5,595 5,237 — — 12,112 12,099 41,050 40,993 U.S. government agency residential mortgage-backed securities 1 — — — — — — 5,475,351 5,460,386 5,475,351 5,460,386 Privately issued residential mortgage-backed securities — — — — 101,192 115,535 — — 101,192 115,535 Commercial mortgage-backed securities guaranteed by U.S. government agencies — — — — — — 3,035,750 3,017,933 3,035,750 3,017,933 Other debt securities 4,400 4,152 — — — — — — 4,400 4,152 Perpetual preferred stock — — 4,796 5,177 10,765 13,297 — — 15,561 18,474 Equity securities and mutual funds 4 759 — — — — 17,420 17,598 17,424 18,357 Total available for sale securities $ 27,747 $ 28,568 $ 10,391 $ 10,414 $ 111,957 $ 128,832 $ 8,541,633 $ 8,509,015 $ 8,691,728 $ 8,676,829 1 U.S. government and government sponsored enterprises are not rated by the nationally-recognized rating agencies as these securities are guaranteed by agencies of the U.S. government or government-sponsored enterprises.
Schedule of Primary Assumptions Used in Other-Than-Temporary Impairment Evaluation [Table Text Block]	December 31, 2016 2015 Unemployment rate Decreasing to 4.6% over the next 12 months and remain at 4.6% thereafter. Decreasing to 4.8% over the next 12 months and remain at 4.8% thereafter. Housing price appreciation/depreciation Starting with current depreciated housing prices based on information derived from the FHFA 1 , appreciating 3.1% over the next 12 months, then flat for the following 12 months and then appreciating at 2% per year thereafter. Starting with current depreciated housing prices based on information derived from the FHFA 1 , appreciating 3.5% over the next 12 months, then flat for the following 12 months and then appreciating at 2% per year thereafter. Estimated liquidation costs Reflect actual historical liquidations costs observed on Jumbo and Alt-A residential mortgage loans in securities owned by the Company. Reflect actual historical liquidations costs observed on Jumbo and Alt-A residential mortgage loans in securities owned by the Company. Discount rates Estimated cash flows were discounted at rates that range from 2.00% to 6.25% based on our current expected yields. Estimated cash flows were discounted at rates that range from 2.00% to 6.25% based on our current expected yields.
Rollforward Other-than-temporary Impairment Credit Losses Recognized in Earnings [Table Text Block]	Year Ended December 31, 2016 2015 2014 Balance of credit-related OTTI recognized on available for sale debt, beginning of period $ 54,504 $ 54,347 $ 67,346 Additions for credit-related OTTI not previously recognized — — — Additions for increases in credit-related OTTI previously recognized when there is no intent to sell and no requirement to sell before recovery of amortized cost — 157 — Reductions for change in intent to hold before recovery — — — Sales — — (12,999 ) Balance of credit-related OTTI recognized on available for sale debt securities, end of period $ 54,504 $ 54,504 $ 54,347
Schedule of Fair Value Option Securities [Table Text Block]	The fair value and net unrealized gain (loss) included in Fair value option securities is as follows (in thousands): December 31, 2016 December 31, 2015 Fair Value Net Unrealized Gain (Loss) Fair Value Net Unrealized Gain (Loss) U.S. government agency residential mortgage-backed securities $ 77,046 $ (1,777 ) $ 444,217 $ (2,060 )
Schedule of Restricted Equity Securities [Table Text Block]	December 31, 2016 2015 Federal Reserve Bank stock $ 36,498 $ 36,148 Federal Home Loan Bank stock 270,541 237,365 Other 201 171 Total $ 307,240 $ 273,684

Derivatives (Tables)

Derivatives (Tables)	12 Months Ended
	Dec. 31, 2016
Derivative Instrument Detail [Abstract]
Derivative Contracts [Table Text Block]	The following table summarizes the fair values of derivative contracts recorded as “derivative contracts” assets and liabilities in the balance sheet at December 31, 2016 (in thousands): Assets Notional 1 Gross Fair Value Netting Adjustments Net Fair Value Before Cash Collateral Cash Collateral Fair Value Net of Cash Collateral Customer risk management programs: Interest rate contracts To-be-announced residential mortgage-backed securities $ 16,949,152 $ 180,695 $ (60,555 ) $ 120,140 $ — $ 120,140 Interest rate swaps 1,403,408 34,442 — 34,442 (4,567 ) 29,875 Energy contracts 835,566 64,140 (28,298 ) 35,842 (71 ) 35,771 Agricultural contracts 53,209 1,382 (515 ) 867 — 867 Foreign exchange contracts 580,886 494,349 — 494,349 (5,183 ) 489,166 Equity option contracts 100,924 4,357 — 4,357 (730 ) 3,627 Total customer risk management programs 19,923,145 779,365 (89,368 ) 689,997 (10,551 ) 679,446 Internal risk management programs 2,514,169 10,426 — 10,426 — 10,426 Total derivative contracts $ 22,437,314 $ 789,791 $ (89,368 ) $ 700,423 $ (10,551 ) $ 689,872 Liabilities Notional¹ Gross Fair Value Netting Adjustments Net Fair Value Before Cash Collateral Cash Collateral Fair Value Net of Cash Collateral Customer risk management programs: Interest rate contracts To-be-announced residential mortgage-backed securities $ 16,637,532 $ 176,928 $ (60,555 ) $ 116,373 $ — $ 116,373 Interest rate swaps 1,403,408 34,442 — 34,442 (11,977 ) 22,465 Energy contracts 820,365 64,306 (28,298 ) 36,008 (31,534 ) 4,474 Agricultural contracts 53,216 1,365 (515 ) 850 (769 ) 81 Foreign exchange contracts 580,712 494,695 — 494,695 (3,630 ) 491,065 Equity option contracts 100,924 4,357 — 4,357 — 4,357 Total customer risk management programs 19,596,157 776,093 (89,368 ) 686,725 (47,910 ) 638,815 Internal risk management programs 2,582,202 25,716 — 25,716 — 25,716 Total derivative contracts $ 22,178,359 $ 801,809 $ (89,368 ) $ 712,441 $ (47,910 ) $ 664,531 1 Notional amounts for commodity contracts are converted into dollar-equivalent amounts based on dollar prices at the inception of the contract. When bilateral netting agreements exist between the Company and its counterparties that create a single legal claim or obligation to pay or receive the net amount in settlement of the individual derivative contracts, the Company reports derivative assets and liabilities on a net by counterparty basis. Contracts may also require the Company to provide or receive cash margin as collateral for derivative assets and liabilities. Derivative assets and liabilities are reported net of cash margin when certain conditions are met. The following table summarizes the fair values of derivative contracts recorded as “derivative contracts” assets and liabilities in the balance sheet at December 31, 2015 (in thousands): Assets Notional 1 Gross Fair Value Netting Adjustments Net Fair Value Before Cash Collateral Cash Collateral Fair Value Net of Cash Collateral Customer risk management programs: Interest rate contracts To-be-announced residential mortgage-backed securities $ 14,583,052 $ 43,270 $ (28,305 ) $ 14,965 $ — $ 14,965 Interest rate swaps 1,332,044 31,744 — 31,744 (1,424 ) 30,320 Energy contracts 470,613 83,045 (22,970 ) 60,075 (18,606 ) 41,469 Agricultural contracts 61,662 2,591 (1,158 ) 1,433 — 1,433 Foreign exchange contracts 546,572 498,830 — 498,830 (4,140 ) 494,690 Equity option contracts 137,278 3,780 — 3,780 (470 ) 3,310 Total customer risk management programs 17,131,221 663,260 (52,433 ) 610,827 (24,640 ) 586,187 Internal risk management programs 22,000 83 — 83 — 83 Total derivative contracts $ 17,153,221 $ 663,343 $ (52,433 ) $ 610,910 $ (24,640 ) $ 586,270 Liabilities Notional¹ Gross Fair Value Netting Adjustments Net Fair Value Before Cash Collateral Cash Collateral Fair Value Net of Cash Collateral Customer risk management programs: Interest rate contracts To-be-announced residential mortgage-backed securities $ 14,168,927 $ 40,141 $ (28,305 ) $ 11,836 $ (1,308 ) $ 10,528 Interest rate swaps 1,332,044 31,928 — 31,928 (20,530 ) 11,398 Energy contracts 463,703 81,869 (22,970 ) 58,899 — 58,899 Agricultural contracts 61,657 2,579 (1,158 ) 1,421 (1,248 ) 173 Foreign exchange contracts 546,405 498,574 — 498,574 (1,951 ) 496,623 Equity option contracts 137,278 3,780 — 3,780 — 3,780 Total customer risk management programs 16,710,014 658,871 (52,433 ) 606,438 (25,037 ) 581,401 Internal risk management programs 75,000 300 — 300 — 300 Total derivative contracts $ 16,785,014 $ 659,171 $ (52,433 ) $ 606,738 $ (25,037 ) $ 581,701 1 Notional amounts for commodity contracts are converted into dollar-equivalent amounts based on dollar prices at the inception of the contract.
Derivative Instruments, Gain (Loss) in Statement of Earnings [Table Text Block]	The following summarizes the pre-tax net gains (losses) on derivative instruments and where they are recorded in the Consolidated Statement of Earnings (in thousands): Year Ended December 31, 2016 2015 2014 Brokerage and Trading Revenue Gain (Loss) on Derivatives, Net Brokerage and Trading Revenue Gain (Loss) on Derivatives, Net Brokerage and Trading Revenue Gain (Loss) on Derivatives, Net Customer risk management programs: Interest rate contracts To-be-announced residential mortgage-backed securities $ 38,523 $ — $ 33,877 $ — $ 27,007 $ — Interest rate swaps 2,589 — 2,066 — 2,494 — Energy contracts 5,027 — 4,060 — 6,572 — Agricultural contracts 111 — 123 — 146 — Foreign exchange contracts 945 — 797 — 1,581 — Equity option contracts — — — — — — Total customer risk management programs 47,195 — 40,923 — 37,800 — Internal risk management programs (4,592 ) (15,685 ) (209 ) 430 — 2,776 Total derivative contracts $ 42,603 $ (15,685 ) $ 40,714 $ 430 $ 37,800 $ 2,776

Loans and Allowances for Cred32

Loans and Allowances for Credit Losses (Tables)	12 Months Ended
	Dec. 31, 2016
Loans Receivable, Net [Abstract]
Schedule of the Loans by Portfolio Segment [Table Text Block]	The portfolio segments of the loan portfolio are as follows (in thousands): December 31, 2016 December 31, 2015 Fixed Rate Variable Rate Non-accrual Total Fixed Rate Variable Rate Non-accrual Total Commercial $ 2,327,085 $ 7,884,786 $ 178,953 $ 10,390,824 $ 1,850,548 $ 8,325,559 $ 76,424 $ 10,252,531 Commercial real estate 624,187 3,179,338 5,521 3,809,046 627,678 2,622,354 9,001 3,259,033 Residential mortgage 1,647,357 256,255 46,220 1,949,832 1,598,992 216,661 61,240 1,876,893 Personal 154,971 684,697 290 839,958 91,816 460,418 463 552,697 Total $ 4,753,600 $ 12,005,076 $ 230,984 $ 16,989,660 $ 4,169,034 $ 11,624,992 $ 147,128 $ 15,941,154 Accruing loans past due (90 days) 1 $ 5 $ 1,207 Foregone interest on nonaccrual loans $ 15,990 $ 7,432 1 Excludes residential mortgage loans guaranteed by agencies of the U.S. government
Rollforward of Allowance For Loan Losses And Accrual for Off-Balnace Sheet Credit Losses [Table Text Block]	The activity in the allowance for loan losses and the accrual for off-balance sheet credit risk related to loan commitments and standby letters of credit for the year ended December 31, 2016 is summarized as follows (in thousands): Commercial Commercial Real Estate Residential Mortgage Personal Nonspecific Allowance Total Allowance for loan losses: Beginning balance $ 130,334 $ 41,391 $ 19,509 $ 4,164 $ 30,126 $ 225,524 Provision for loan losses 43,980 8,075 (1,972 ) 7,310 (1,926 ) 55,467 Loans charged off (35,828 ) — (1,312 ) (5,448 ) — (42,588 ) Recoveries 1,727 1,283 1,999 2,747 — 7,756 Ending balance $ 140,213 $ 50,749 $ 18,224 $ 8,773 $ 28,200 $ 246,159 Accrual for off-balance sheet credit risk: Beginning balance $ 1,506 $ 153 $ 30 $ 22 $ — $ 1,711 Provision for off-balance sheet credit risk 9,557 (30 ) 20 (14 ) — 9,533 Ending balance $ 11,063 $ 123 $ 50 $ 8 $ — $ 11,244 Total provision for credit losses $ 53,537 $ 8,045 $ (1,952 ) $ 7,296 $ (1,926 ) $ 65,000 The activity in the allowance for loan losses and the accrual for off-balance sheet credit risk related to loan commitments and standby letters of credit for the year ended December 31, 2015 is summarized as follows (in thousands): Commercial Commercial Real Estate Residential Mortgage Personal Nonspecific Allowance Total Allowance for loan losses: Beginning balance $ 90,875 $ 42,445 $ 23,458 $ 4,233 $ 28,045 $ 189,056 Provision for loan losses 43,464 (11,189 ) (3,004 ) 2,167 2,081 33,519 Loans charged off (6,734 ) (944 ) (2,205 ) (5,288 ) — (15,171 ) Recoveries 2,729 11,079 1,260 3,052 — 18,120 Ending balance $ 130,334 $ 41,391 $ 19,509 $ 4,164 $ 30,126 $ 225,524 Accrual for off-balance sheet credit risk: Beginning balance $ 475 $ 707 $ 28 $ 20 $ — $ 1,230 Provision for off-balance sheet credit risk 1,031 (554 ) 2 2 — 481 Ending balance $ 1,506 $ 153 $ 30 $ 22 $ — $ 1,711 Total provision for credit losses $ 44,495 $ (11,743 ) $ (3,002 ) $ 2,169 $ 2,081 $ 34,000 The activity in the allowance for loan losses and the accrual for off-balance sheet credit risk related to loan commitments and standby letters of credit for the year ended December 31, 2014 is summarized as follows (in thousands): Commercial Commercial Real Estate Residential Mortgage Personal Nonspecific Allowance Total Allowance for loan losses: Beginning balance $ 79,180 $ 41,573 $ 29,465 $ 6,965 $ 28,213 $ 185,396 Provision for loan losses 9,561 (4,084 ) (3,559 ) (892 ) (168 ) 858 Loans charged off (3,569 ) (2,047 ) (4,448 ) (6,168 ) — (16,232 ) Recoveries 5,703 7,003 2,000 4,328 — 19,034 Ending balance $ 90,875 $ 42,445 $ 23,458 $ 4,233 $ 28,045 $ 189,056 Accrual for off-balance sheet credit risk: Beginning balance $ 119 $ 1,876 $ 90 $ 3 $ — $ 2,088 Provision for off-balance sheet credit risk 356 (1,169 ) (62 ) 17 — (858 ) Ending balance $ 475 $ 707 $ 28 $ 20 $ — $ 1,230 Total provision for credit losses $ 9,917 $ (5,253 ) $ (3,621 ) $ (875 ) $ (168 ) $ — The allowance for loan losses and recorded investment of the related loans by portfolio segment for each impairment measurement method at December 31, 2016 is as follows (in thousands): Collectively Measured for Impairment Individually Measured for Impairment Total Recorded Investment Related Allowance Recorded Investment Related Allowance Recorded Investment Related Allowance Commercial $ 10,211,871 $ 139,416 $ 178,953 $ 797 $ 10,390,824 $ 140,213 Commercial real estate 3,803,525 50,749 5,521 — 3,809,046 50,749 Residential mortgage 1,903,612 18,178 46,220 46 1,949,832 18,224 Personal 839,668 8,773 290 — 839,958 8,773 Total 16,758,676 217,116 230,984 843 16,989,660 217,959 Nonspecific allowance — — — — — 28,200 Total $ 16,758,676 $ 217,116 $ 230,984 $ 843 $ 16,989,660 $ 246,159 The allowance for loan losses and recorded investment of the related loans by portfolio segment for each impairment measurement method at December 31, 2015 is as follows (in thousands): Collectively Measured for Impairment Individually Measured for Impairment Total Recorded Investment Related Allowance Recorded Investment Related Allowance Recorded Investment Related Allowance Commercial $ 10,176,107 $ 114,027 $ 76,424 $ 16,307 $ 10,252,531 $ 130,334 Commercial real estate 3,250,032 41,373 9,001 18 3,259,033 41,391 Residential mortgage 1,815,653 19,441 61,240 68 1,876,893 19,509 Personal 552,234 4,164 463 — 552,697 4,164 Total 15,794,026 179,005 147,128 16,393 15,941,154 195,398 Nonspecific allowance — — — — — 30,126 Total $ 15,794,026 $ 179,005 $ 147,128 $ 16,393 $ 15,941,154 $ 225,524
Schedule of Allowance for Loan Losses and Recorded Investment by Portfolio Segment for Risk Graded and Non-Risk Graded Loans [Table Text Block]	The allowance for loan losses and recorded investment of the related loans by portfolio segment for risk graded and non-risk graded loans at December 31, 2016 is as follows (in thousands): Internally Risk Graded Non-Graded Total Recorded Investment Related Allowance Recorded Investment Related Allowance Recorded Investment Related Allowance Commercial $ 10,360,725 $ 139,293 $ 30,099 $ 920 $ 10,390,824 $ 140,213 Commercial real estate 3,809,046 50,749 — — 3,809,046 50,749 Residential mortgage 243,703 2,893 1,706,129 15,331 1,949,832 18,224 Personal 744,602 5,035 95,356 3,738 839,958 8,773 Total 15,158,076 197,970 1,831,584 19,989 16,989,660 217,959 Nonspecific allowance — — — — — 28,200 Total $ 15,158,076 $ 197,970 $ 1,831,584 $ 19,989 $ 16,989,660 $ 246,159 The allowance for loan losses and recorded investment of the related loans by portfolio segment for risk graded and non-risk graded loans at December 31, 2015 is as follows (in thousands): Internally Risk Graded Non-Graded Total Recorded Investment Related Allowance Recorded Investment Related Allowance Recorded Investment Related Allowance Commercial $ 10,227,303 $ 129,426 $ 25,228 $ 908 $ 10,252,531 $ 130,334 Commercial real estate 3,259,033 41,391 — — 3,259,033 41,391 Residential mortgage 196,701 2,883 1,680,192 16,626 1,876,893 19,509 Personal 467,955 1,390 84,742 2,774 552,697 4,164 Total 14,150,992 175,090 1,790,162 20,308 15,941,154 195,398 Nonspecific allowance — — — — — 30,126 Total $ 14,150,992 $ 175,090 $ 1,790,162 $ 20,308 $ 15,941,154 $ 225,524
Schedule of Credit Quality Indicators [Table Text Block]	The following table summarizes the Company’s loan portfolio at December 31, 2016 by the risk grade categories (in thousands): Internally Risk Graded Non-Graded Performing Pass Other Loans Especially Mentioned Accruing Substandard Nonaccrual Performing Nonaccrual Total Commercial: Energy $ 1,937,790 $ 119,583 $ 307,996 $ 132,499 — — $ 2,497,868 Services 3,052,002 10,960 37,855 8,173 — — 3,108,990 Wholesale/retail 1,535,463 16,886 13,062 11,407 — — 1,576,818 Manufacturing 468,314 26,532 15,198 4,931 — — 514,975 Healthcare 2,140,458 44,472 16,161 825 — — 2,201,916 Other commercial and industrial 433,789 5,309 — 21,060 30,041 58 490,257 Total commercial 9,567,816 223,742 390,272 178,895 30,041 58 10,390,824 Commercial real estate: Residential construction and land development 131,630 — 470 3,433 — — 135,533 Retail 756,418 4,745 399 326 — — 761,888 Office 798,462 — — 426 — — 798,888 Multifamily 898,800 — 4,434 38 — — 903,272 Industrial 871,673 — — 76 — — 871,749 Other commercial real estate 336,488 — 6 1,222 — — 337,716 Total commercial real estate 3,793,471 4,745 5,309 5,521 — — 3,809,046 Residential mortgage: Permanent mortgage 238,769 1,186 2,331 1,417 741,679 21,438 1,006,820 Permanent mortgages guaranteed by U.S. government agencies — — — — 187,541 11,846 199,387 Home equity — — — — 732,106 11,519 743,625 Total residential mortgage 238,769 1,186 2,331 1,417 1,661,326 44,803 1,949,832 Personal 743,451 — 1,054 97 95,163 193 839,958 Total $ 14,343,507 $ 229,673 $ 398,966 $ 185,930 $ 1,786,530 $ 45,054 $ 16,989,660 The following table summarizes the Company’s loan portfolio at December 31, 2015 by the risk grade categories (in thousands): Internally Risk Graded Non-Graded Performing Pass Other Loans Especially Mentioned Accruing Substandard Nonaccrual Performing Nonaccrual Total Commercial: Energy $ 2,580,694 $ 325,663 $ 129,782 61,189 $ — $ — $ 3,097,328 Services 2,763,929 3,296 6,761 10,290 — — 2,784,276 Wholesale/retail 1,394,596 18,184 6,365 2,919 — — 1,422,064 Manufacturing 534,966 19,560 1,872 331 — — 556,729 Healthcare 1,876,745 5,563 — 1,072 — — 1,883,380 Other commercial and industrial 477,551 5,479 — 496 25,101 127 508,754 Total commercial 9,628,481 377,745 144,780 76,297 25,101 127 10,252,531 Commercial real estate: Residential construction and land development 154,369 1,355 293 4,409 — — 160,426 Retail 788,708 6,046 426 1,319 — — 796,499 Office 636,210 291 555 651 — — 637,707 Multifamily 744,299 — 6,512 274 — — 751,085 Industrial 563,093 — — 76 — — 563,169 Other commercial real estate 347,864 — 11 2,272 — — 350,147 Total commercial real estate 3,234,543 7,692 7,797 9,001 — — 3,259,033 Residential mortgage: Permanent mortgage 192,367 89 1,932 2,313 721,964 26,671 945,336 Permanent mortgages guaranteed by U.S. government agencies — — — — 175,037 21,900 196,937 Home equity — — — — 724,264 10,356 734,620 Total residential mortgage 192,367 89 1,932 2,313 1,621,265 58,927 1,876,893 Personal 467,808 3 14 130 84,409 333 552,697 Total $ 13,523,199 $ 385,529 $ 154,523 87,741 $ 1,730,775 $ 59,387 $ 15,941,154
Summary of Impaired Loans [Table Text Block]	As of December 31, 2016 Year Ended Recorded Investment December 31, 2016 Unpaid Principal Balance Total With No With Allowance Related Allowance Average Recorded Interest Income Recognized Commercial: Energy $ 146,897 $ 132,499 $ 121,418 $ 11,081 $ 762 $ 80,100 $ — Services 11,723 8,173 8,173 — — 9,232 — Wholesale/retail 17,669 11,407 11,407 — — 7,163 — Manufacturing 5,320 4,931 4,931 — — 2,631 — Healthcare 1,147 825 825 — — 949 — Other commercial and industrial 29,006 21,118 21,083 35 35 10,870 — Total commercial 211,762 178,953 167,837 11,116 797 110,945 — Commercial real estate: Residential construction and land development 4,951 3,433 3,433 — — 3,921 — Retail 530 326 326 — — 823 — Office 521 426 426 — — 539 — Multifamily 1,000 38 38 — — 156 — Industrial 76 76 76 — — 76 — Other commercial real estate 7,349 1,222 1,222 — — 1,747 — Total commercial real estate 14,427 5,521 5,521 — — 7,262 — Residential mortgage: Permanent mortgage 28,830 22,855 22,809 46 46 25,920 1,255 Permanent mortgage guaranteed by U.S. government agencies 1 205,564 199,387 199,387 — — 193,889 7,759 Home equity 12,611 11,519 11,519 — — 10,937 — Total residential mortgage 247,005 233,761 233,715 46 46 230,746 9,014 Personal 332 290 290 — — 377 — Total $ 473,526 $ 418,525 $ 407,363 $ 11,162 $ 843 $ 349,330 $ 9,014 1 All permanent mortgage loans guaranteed by U.S. government agencies are considered impaired as we do not expect full collection of contractual principal and interest. At December 31, 2016 , $12 million of these loans are nonaccruing and $188 million are accruing based on the guarantee by U.S. government agencies. Generally, no interest income is recognized on impaired loans until all principal balances, including amounts charged-off, have been recovered. As of December 31, 2015 Year Ended Recorded Investment December 31, 2015 Unpaid Principal Balance Total With No Allowance With Allowance Related Allowance Average Recorded Investment Interest Income Recognized Commercial: Energy $ 63,910 $ 61,189 $ 18,330 $ 42,859 $ 16,115 $ 31,303 $ — Services 13,449 10,290 9,657 633 148 7,746 — Wholesale/retail 8,582 2,919 2,907 12 9 3,534 — Manufacturing 665 331 331 — — 391 — Healthcare 1,352 1,072 931 141 35 1,226 — Other commercial and industrial 8,304 623 623 — — 777 — Total commercial 96,262 76,424 32,779 43,645 16,307 44,977 — Commercial real estate: Residential construction and land development 8,963 4,409 4,409 — — 4,854 — Retail 1,923 1,319 1,319 — — 2,622 — Office 937 651 651 — — 2,035 — Multifamily 1,192 274 274 — — 137 — Industrial 76 76 76 — — 38 — Other commercial real estate 8,363 2,272 2,113 159 18 4,092 — Total commercial real estate 21,454 9,001 8,842 159 18 13,778 — Residential mortgage: Permanent mortgage 37,273 28,984 28,868 116 68 31,914 1,242 Permanent mortgage guaranteed by U.S. government agencies 1 202,984 196,937 196,937 — — 196,827 7,814 Home equity 10,988 10,356 10,356 — — 9,960 — Total residential mortgage 251,245 236,277 236,161 116 68 238,701 9,056 Personal 489 463 463 — — 515 — Total $ 369,450 $ 322,165 $ 278,245 $ 43,920 $ 16,393 $ 297,971 $ 9,056 1 All permanent mortgage loans guaranteed by U.S. government agencies are considered impaired as we do not expect full collection of contractual principal and interest. At December 31, 2015 , $22 million of these loans are nonaccruing and $175 million are accruing based on the guarantee by U.S. government agencies.
Troubled Debt Restructurings [Table Text Block]	A summary of troubled debt restructurings ("TDRs") by accruing status as of December 31, 2016 is as follows (in thousands): As of December 31, 2016 Recorded Investment Performing in Accordance With Modified Terms Not Performing in Accordance With Modified Terms Specific Allowance Amounts Charged-Off During the Year Ended December 31, 2016 Nonaccruing TDRs: Commercial: Energy $ 16,893 $ 10,867 $ 6,026 $ — $ 4,401 Services 7,527 6,830 697 — — Wholesale/Retail 11,291 11,251 40 — — Manufacturing 224 224 — — — Healthcare 607 — 607 — — Other commercial and industrial 337 53 284 — — Total commercial 36,879 29,225 7,654 — 4,401 Commercial real estate: Residential construction and land development 690 97 593 — — Retail 326 326 — — — Office 143 143 — — — Multifamily — — — — — Industrial — — — — — Other commercial real estate 548 548 — — — Total commercial real estate 1,707 1,114 593 — — Residential mortgage: Permanent mortgage 14,876 10,175 4,701 46 28 Permanent mortgage guaranteed by U.S. government agencies 6,702 2,241 4,461 — — Home equity 5,346 4,458 888 — 230 Total residential mortgage 26,924 16,874 10,050 46 258 Personal 237 236 1 — 73 Total nonaccruing TDRs 65,747 47,449 18,298 46 4,732 Accruing TDRs: Residential mortgage: Permanent mortgages guaranteed by U.S. government agencies 81,370 27,289 54,081 — — Total residential mortgage 81,370 27,289 54,081 — — Total accruing TDRs 81,370 27,289 54,081 — — Total TDRs $ 147,117 $ 74,738 $ 72,379 $ 46 $ 4,732 A summary of troubled debt restructurings by accruing status as of December 31, 2015 is as follows (in thousands): As of December 31, 2015 Recorded Investment Performing in Accordance With Modified Terms Not Performing in Accordance With Modified Terms Specific Allowance Amounts Charged-off During the Year Ended December 31, 2015 Nonaccruing TDRs: Commercial: Energy $ 2,304 $ 2,304 $ — $ — $ 928 Services 9,027 8,210 817 148 — Wholesale/retail 2,758 2,706 52 9 — Manufacturing 282 282 — — — Healthcare 673 673 — — — Other commercial and industrial 621 89 532 — — Total commercial 15,665 14,264 1,401 157 928 Commercial real estate: Residential construction and land development 2,328 1,556 772 — — Retail 1,319 942 377 — — Office 165 165 — — — Multifamily — — — — — Industrial — — — — — Other commercial real estate 920 478 442 — — Total commercial real estate 4,732 3,141 1,591 — — Residential mortgage: Permanent mortgage 16,618 9,043 7,575 68 192 Permanent mortgage guaranteed by U.S. government agencies 11,136 139 10,997 — — Home equity 5,159 4,218 941 — 80 Total residential mortgage 32,913 13,400 19,513 68 272 Personal 324 297 27 — 11 Total nonaccuring TDRs 53,634 31,102 22,532 225 1,211 Accruing TDRs: Residential mortgage: Permanent mortgages guaranteed by U.S. government agencies 74,050 23,029 51,021 — — Total residential mortgage 74,050 23,029 51,021 — — Total accruing TDRs 74,050 23,029 51,021 — — Total TDRs $ 127,684 $ 54,131 $ 73,553 $ 225 $ 1,211 Troubled debt restructurings generally consist of interest rate concessions, payment stream concessions or a combination of concessions to distressed borrowers. The following table details the recorded balance of loans at December 31, 2016 by class that were restructured during the year ended December 31, 2016 by primary type of concession (in thousands): Year Ended December 31, 2016 Accruing Nonaccrual Total Payment Stream Combination & Other Total Interest Rate Payment Stream Combination & Other Total Commercial: Energy $ — $ — $ — $ — $ — $ 16,892 $ 16,892 $ 16,892 Services — — — — — — — — Wholesale/retail — — — — — 9,103 9,103 9,103 Manufacturing — — — — — — — — Healthcare — — — — — — — — Other commercial and industrial — — — — — — — — Total commercial — — — — — 25,995 25,995 25,995 Commercial real estate: Residential construction and land development — — — — — — — — Retail — — — — — — — — Office — — — — — — — — Multifamily — — — — — — — — Industrial — — — — — — — — Other commercial real estate — — — — — — — — Total commercial real estate — — — — — — — — Residential mortgage: Permanent mortgage — — — — 1,036 328 1,364 1,364 Permanent mortgage guaranteed by U.S. government agencies 11,879 10,042 21,921 — — 979 979 22,900 Home equity — — — — 46 2,077 2,123 2,123 Total residential mortgage 11,879 10,042 21,921 — 1,082 3,384 4,466 26,387 Personal — — — — — 77 77 77 Total $ 11,879 $ 10,042 $ 21,921 $ — $ 1,082 $ 29,456 $ 30,538 $ 52,459 The following table details the recorded balance of loans by class that were restructured during the year ended December 31, 2015 by primary type of concession (in thousands): Year Ended December 31, 2015 Accruing Nonaccrual Total Payment Stream Combination & Other Total Interest Rate Payment Stream Combination & Other Total Commercial: Energy $ — $ — $ — $ — $ — $ 2,304 $ 2,304 $ 2,304 Services — — — — — 7,577 7,577 7,577 Wholesale/retail — — — — — — — — Manufacturing — — — — — — — — Healthcare — — — 673 — — 673 673 Other commercial and industrial — — — — — 57 57 57 Total commercial — — — 673 — 9,938 10,611 10,611 Commercial real estate: Residential construction and land development — — — — 329 — 329 329 Retail — — — — — — — — Office — — — — — — — — Multifamily — — — — — — — — Industrial — — — — — — — — Other commercial real estate — — — — — — — — Total commercial real estate — — — — 329 — 329 329 Residential mortgage: Permanent mortgage — — — — 3,004 1,051 4,055 4,055 Permanent mortgage guaranteed by U.S. government agencies 17,717 10,384 28,101 — 1,264 1,837 3,101 31,202 Home equity — — — 57 181 1,870 2,108 2,108 Total residential mortgage 17,717 10,384 28,101 57 4,449 4,758 9,264 37,365 Personal — — — — — 115 115 115 Total $ 17,717 $ 10,384 $ 28,101 $ 730 $ 4,778 $ 14,811 $ 20,319 $ 48,420 The following table summarizes, by loan class, the recorded investment at December 31, 2016 and 2015 , respectively of loans modified as TDRs within the previous 12 months and for which there was a payment default during the years ended December 31, 2016 and 2015 , respectively (in thousands): Year Ended December 31, 2016 December 31, 2015 Accruing Nonaccrual Total Accruing Nonaccrual Total Commercial: Energy $ — $ 8,593 $ 8,593 $ — $ — $ — Services — — — — — — Wholesale/retail — — — — — — Manufacturing — — — — — — Healthcare — — — — — — Other commercial and industrial — — — — 38 38 Total commercial — 8,593 8,593 — 38 38 Commercial real estate: Residential construction and land development — — — — 329 329 Retail — — — — — — Office — — — — — — Multifamily — — — — — — Industrial — — — — — — Other commercial real estate — — — — — — Total commercial real estate — — — — 329 329 Residential mortgage: Permanent mortgage — 544 544 — 3,034 3,034 Permanent mortgage guaranteed by U.S. government agencies 17,154 647 17,801 27,223 3,101 30,324 Home equity — 585 585 — 524 524 Total residential mortgage 17,154 1,776 18,930 27,223 6,659 33,882 Personal — 5 5 — 13 13 Total $ 17,154 $ 10,374 $ 27,528 $ 27,223 $ 7,039 $ 34,262 A payment default is defined as being 30 days or more past due. The table above includes loans that experienced a payment default during the period, but may be performing in accordance with the modified terms as of the balance sheet date.
Summary of Loans by Aging Status [Table Text Block]	A summary of loans currently performing, loans past due and accruing and nonaccrual loans as of December 31, 2016 is as follows (in thousands): Past Due Current 30 to 59 Days 60 to 89 Days 90 Days or More Nonaccrual Total Commercial: Energy $ 2,364,890 $ 479 — $ — $ 132,499 $ 2,497,868 Services 3,099,605 191 1,021 — 8,173 3,108,990 Wholesale/retail 1,561,650 3,761 — — 11,407 1,576,818 Manufacturing 509,662 382 — — 4,931 514,975 Healthcare 2,201,050 — 41 — 825 2,201,916 Other commercial and industrial 468,981 155 3 — 21,118 490,257 Total commercial 10,205,838 4,968 1,065 — 178,953 10,390,824 Commercial real estate: Residential construction and land development 132,100 — — — 3,433 135,533 Retail 761,562 — — — 326 761,888 Office 798,462 — — — 426 798,888 Multifamily 903,234 — — — 38 903,272 Industrial 871,673 — — — 76 871,749 Other commercial real estate 336,488 6 — — 1,222 337,716 Total commercial real estate 3,803,519 6 — — 5,521 3,809,046 Residential mortgage: Permanent mortgage 979,386 3,299 1,280 — 22,855 1,006,820 Permanent mortgages guaranteed by U.S. government agencies 40,594 17,465 13,803 115,679 11,846 199,387 Home equity 729,493 2,276 337 — 11,519 743,625 Total residential mortgage 1,749,473 23,040 15,420 115,679 46,220 1,949,832 Personal 838,811 589 263 5 290 839,958 Total $ 16,597,641 $ 28,603 16,748 $ 115,684 $ 230,984 $ 16,989,660 A summary of loans currently performing, loans past due and accruing and nonaccrual loans as of December 31, 2015 is as follows (in thousands): Past Due Current 30 to 59 Days 60 to 89 Days 90 Days or More Nonaccrual Total Commercial: Energy $ 3,033,504 $ 2,635 — $ — $ 61,189 $ 3,097,328 Services 2,769,895 66 4,025 — 10,290 2,784,276 Wholesale/retail 1,418,396 49 — 700 2,919 1,422,064 Manufacturing 556,398 — — — 331 556,729 Healthcare 1,879,873 2,435 — — 1,072 1,883,380 Other commercial and industrial 507,929 84 16 102 623 508,754 Total commercial 10,165,995 5,269 4,041 802 76,424 10,252,531 Commercial real estate: Residential construction and land development 156,017 — — — 4,409 160,426 Retail 795,180 — — — 1,319 796,499 Office 637,056 — — — 651 637,707 Multifamily 742,697 8,114 — — 274 751,085 Industrial 563,093 — — — 76 563,169 Other commercial real estate 347,498 — — 377 2,272 350,147 Total commercial real estate 3,241,541 8,114 — 377 9,001 3,259,033 Residential mortgage: Permanent mortgage 913,062 3,290 — — 28,984 945,336 Permanent mortgages guaranteed by U.S. government agencies 33,653 16,986 13,397 111,001 21,900 196,937 Home equity 721,149 2,379 716 20 10,356 734,620 Total residential mortgage 1,667,864 22,655 14,113 111,021 61,240 1,876,893 Personal 551,533 665 28 8 463 552,697 Total $ 15,626,933 $ 36,703 18,182 $ 112,208 $ 147,128 $ 15,941,154

Premises and Equipment Premises

Premises and Equipment Premises and Equipment (Tables)	12 Months Ended
	Dec. 31, 2016
Property, Plant and Equipment [Abstract]
Premises and Equipment [Table Text Block]	Premises and equipment at December 31 are summarized as follows (in thousands): December 31, 2016 2015 Land $ 70,552 $ 72,612 Buildings and improvements 250,311 225,181 Software 158,155 142,476 Furniture and equipment 217,399 194,715 Construction in progress 36,743 39,886 Premises and equipment 733,160 674,870 Less accumulated depreciation 407,311 368,380 Premises and equipment, net of accumulated depreciation $ 325,849 $ 306,490

Goodwill and Intangible Assets

Goodwill and Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2016
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Business Acquisitions, by Acquisition [Table Text Block]	A summary of the preliminary purchase price allocation and resulting goodwill follows (in thousands): Cash and cash equivalents $ 166,215 Securities 14,431 Loans 1 444,482 Premises and equipments, net 8,035 Intangible assets – Core deposit premium 6,510 Other assets 3,599 Total assets acquired 643,272 Deposits 598,735 Other borrowings 7,217 Other liabilities 980 Total liabilities assumed 606,932 Net assets acquired 36,340 Less: purchase price 102,500 Goodwill $ 66,160 1 Loans are presented net of participations sold to BOKF NA.
Schedule of Finite-Lived Intangible Assets [Table Text Block]	The following table presents the original cost and accumulated amortization of intangible assets (in thousands): Dec. 31, 2016 2015 Core deposit premiums $ 35,879 $ 29,369 Less accumulated amortization 29,369 29,101 Net core deposit premiums 6,510 268 Other identifiable intangible assets 60,951 55,509 Less accumulated amortization 20,530 11,868 Net other identifiable intangible assets 40,421 43,641 Total intangible assets, net $ 46,931 $ 43,909
Schedule of Finite-Lived Intangible Assets, Future Amortization Expense [Table Text Block]	Expected amortization expense for intangible assets that will continue to be amortized (in thousands): Core Deposit Premiums Other Identifiable Intangible Assets Total 2017 $ 808 $ 4,565 $ 5,373 2018 732 3,908 4,640 2019 716 3,556 4,272 2020 697 3,420 4,117 2021 675 3,063 3,738 Thereafter 2,882 21,909 24,791 $ 6,510 $ 40,421 $ 46,931
Schedule of Goodwill [Table Text Block]	The changes in the carrying value of goodwill by operating segment are as follows (in thousands): Commercial Banking Consumer Banking Wealth Management Funds Management and Other Total Balance, December 31, 2014 Goodwill $ 269,363 $ 39,251 $ 69,394 $ — $ 378,008 Accumulated impairment losses — (228 ) — — (228 ) 269,363 39,023 69,394 — 377,780 Goodwill acquired during 2015 7,681 — — — 7,681 Balance, December 31, 2015 Goodwill 277,044 39,251 69,394 — 385,689 Accumulated impairment losses — (228 ) — — (228 ) 277,044 39,023 69,394 — 385,461 Goodwill acquired during 2016 1,210 — 2,126 66,160 69,496 Adjustment 1 (6,058 ) — — — (6,058 ) Balance, December 31, 2016 Goodwill 272,196 39,251 71,520 66,160 449,127 Accumulated impairment losses — (228 ) — — (228 ) $ 272,196 $ 39,023 $ 71,520 $ 66,160 $ 448,899 1 Completion of an external audit of Heartland Food Products resulted in a reallocation of the purchase price between net assets acquired, intangible assets and goodwill during 2016.

Mortgage Banking Activities (Ta

Mortgage Banking Activities (Tables)	12 Months Ended
	Dec. 31, 2016
Mortgage Banking [Abstract]
Components of Residential Mortgage Loans Held For Sale [Table Text Block]	The unpaid principal balance of residential mortgage loans held for sale, notional amounts of derivative contracts related to residential mortgage loan commitments and forward contract sales and their related fair values included in Mortgage loans held for sale on the Consolidated Balance Sheets were (in thousands): December 31, 2016 December 31, 2015 Unpaid Principal Balance/ Notional Fair Value Unpaid Principal Balance/ Notional Fair Value Residential mortgage loans held for sale $ 286,414 $ 286,971 $ 293,637 $ 299,505 Residential mortgage loan commitments 318,359 9,733 601,147 8,134 Forward sales contracts 569,543 5,193 884,710 800 $ 301,897 $ 308,439
Mortgage Banking Revenue [Table Text Block]	Mortgage banking revenue was as follows (in thousands): Year Ended 2016 2015 2014 Production revenue: Net realized gains on sales of mortgage loans $ 68,947 $ 67,407 $ 56,696 Net change in unrealized gain on mortgage loans held for sale (5,311 ) (784 ) 5,357 Net change in the fair value of mortgage loan commitments 1,599 (1,837 ) 7,315 Net change in the fair value of forward sales contracts 4,393 4,801 (8,307 ) Total production revenue 69,628 69,587 61,061 Servicing revenue 64,286 56,415 48,032 Total mortgage banking revenue $ 133,914 $ 126,002 $ 109,093
Summary of Mortgage Servicing Rights [Table Text Block]	The following represents a summary of mortgage servicing rights (Dollars in thousands): December 31, 2016 2015 2014 Number of residential mortgage loans serviced for others 139,340 131,859 117,483 Outstanding principal balance of residential mortgage loans serviced for others $ 21,997,568 $ 19,678,226 $ 16,162,887 Weighted average interest rate 3.97 % 4.12 % 4.29 % Remaining contractual term (in months) 301 300 296
Activity in Capitalized Mortgage Servicing Rights [Table Text Block]	Activity in capitalized mortgage servicing rights during the three years ended December 31, 2016 is as follows (in thousands): Purchased Originated Total Balance, December 31, 2013 $ 15,935 $ 137,398 $ 153,333 Additions, net — 54,413 54,413 Change in fair value due to loan runoff (2,357 ) (16,968 ) (19,325 ) Change in fair value due to market changes (2,464 ) (13,981 ) (16,445 ) Balance, December 31, 2014 11,114 160,862 171,976 Additions, net — 79,546 79,546 Change in fair value due to loan runoff (2,645 ) (25,419 ) (28,064 ) Change in fair value due to market changes 1,442 (6,295 ) (4,853 ) Balance, December 31, 2015 9,911 208,694 218,605 Additions, net — 71,405 71,405 Change in fair value due to loan runoff (2,844 ) (37,900 ) (40,744 ) Change in fair value due to market changes 1,842 (4,035 ) (2,193 ) Balance, December 31, 2016 $ 8,909 $ 238,164 $ 247,073
Assumptions to Value Mortgage Servicing Rights [Table Text Block]	Significant assumptions used to determine fair value considered to be significant unobservable inputs were as follows: December 31, 2016 2015 Discount rate – risk-free rate plus a market premium 10.08% 10.11% Prepayment rate - based upon loan interest rate, original term and loan type 8.98%-16.91% 7.41% - 23.88% Loan servicing costs – annually per loan based upon loan type: Performing loans $63 - $120 $63 - $105 Delinquent loans $150 - $500 $150 - $500 Loans in foreclosure $650 - $4,250 $650 - $4,250 Primary/secondary mortgage rate spread 105 bps 130 bps Escrow earnings rate – indexed to rates paid on deposit accounts with comparable average life 1.98% 1.73%
Aging Status of Mortgage Loans Serviced For Others [Table Text Block]	The aging status of our mortgage loans serviced for others by investor at December 31, 2016 follows (in thousands): Past Due Current 30 to 59 Days 60 to 89 Days 90 Days or More Total FHLMC $ 7,950,818 $ 52,434 $ 9,812 $ 25,670 $ 8,038,734 FNMA 6,922,833 44,532 11,233 21,486 7,000,084 GNMA 6,304,914 181,669 56,534 22,471 6,565,588 Other 390,109 763 351 1,939 393,162 Total $ 21,568,674 $ 279,398 $ 77,930 $ 71,566 $ 21,997,568
Activity in Accrual for Losses On Loans Sold With Recourse [Table Text Block]	The activity in the accrual for losses on loans sold with recourse included in Other liabilities in the Consolidated Balance Sheets is summarized as follows (in thousands): Year Ended 2016 2015 2014 Beginning balance $ 4,649 $ 7,299 $ 9,562 Provision for recourse losses 725 (982 ) 354 Loans charged off, net (1,358 ) (1,668 ) (2,617 ) Ending balance $ 4,016 $ 4,649 $ 7,299
Summary of Unresolved Deficiency Requests [Table Text Block]	A summary of unresolved deficiency requests from the agencies follows (in thousands, except for number of unresolved deficiency requests): December 31, 2016 2015 Number of unresolved deficiency requests 233 198 Aggregate outstanding principal balance subject to unresolved deficiency requests $ 17,382 $ 15,624 Unpaid principal balance subject to indemnification by the Company 5,803 4,365
Activity in Accruals for Mortgage Losses [Table Text Block]	The activity in the accruals for mortgage losses related to repurchases is summarized as follows (in thousands). December 31, 2016 2015 Beginning balance $ 3,359 $ 3,220 Provision for losses 27 353 Charge-offs, net (598 ) (214 ) Ending balance $ 2,788 $ 3,359

Deposits (Tables)

Deposits (Tables)	12 Months Ended
	Dec. 31, 2016
Deposits [Abstract]
Interest Expense on Deposits Disclosure [Table Text Block]	Interest expense on deposits is summarized as follows (in thousands): Year Ended December 31, 2016 2015 2014 Transaction deposits $ 13,906 $ 8,821 $ 9,757 Savings 386 383 401 Time: Certificates of deposits under $100,000 8,776 11,894 14,278 Certificates of deposits $100,000 and over 10,123 10,643 11,878 Other time deposits 7,303 12,429 14,369 Total time 26,202 34,966 40,525 Total $ 40,494 $ 44,170 $ 50,683

Other Borrowings Other Borrowin

Other Borrowings Other Borrowings (Tables)	12 Months Ended
	Dec. 31, 2016
Debt Disclosure [Abstract]
Schedule of Other Borrowings [Table Text Block]	Information relating to other borrowings is summarized as follows (dollars in thousands): As of Year Ended December 31, 2016 December 31, 2016 Balance Rate Average Balance Rate Maximum Parent company and other non-bank subsidiaries: Trust preferred debt $ 7,217 3.28 % $ 611 3.27 % $ 7,217 Other 1,092 8.27 % 2,073 16.11 % 3,157 Total other borrowings 8,309 2,684 13.19 % Subordinated debentures 144,640 5.60 % 74,428 5.59 % $ 145,393 Total parent company and other non-bank subsidiaries 152,949 77,112 5.86 % BOKF, NA: Funds purchased 57,929 0.38 % 78,222 0.24 % 567,103 Repurchase agreements 668,661 0.02 % 589,145 0.04 % 668,661 Other borrowings: Federal Home Loan Bank advances 4,800,000 0.72 % 5,985,656 0.55 % 6,500,000 GNMA repurchase liability 22,471 4.26 % 15,637 4.74 % 22,471 Other 15,292 2.66 % 15,670 2.41 % 15,797 Total other borrowings 4,837,763 6,016,963 0.57 % Subordinated debentures — — % 140,414 1.35 % 226,434 Total BOKF, NA 5,564,353 6,824,744 0.54 % Total other borrowed funds $ 5,717,302 $ 6,901,856 0.60 % As of Year Ended December 31, 2015 December 31, 2015 Balance Rate Average Balance Rate Maximum Parent company and other non-bank subsidiaries: Trust preferred debt $ — — % $ — — % $ — Other — — % — — % — Total other borrowings — — — % Subordinated debentures — — % — — % — Total parent company and other non-bank subsidiaries — — — % BOKF, NA: Funds purchased 491,192 0.15 % 73,219 0.09 % 491,192 Repurchase agreements 722,444 0.02 % 623,921 0.04 % 1,008,144 Other borrowings: Federal Home Loan Bank advances 4,800,000 0.48 % 4,921,739 0.28 % 5,000,000 GNMA repurchase liability 19,478 4.75 % 16,668 4.95 % 19,478 Other 18,402 2.70 % 18,768 2.35 % 26,058 Total other borrowings 4,837,880 4,957,175 0.33 % Subordinated debentures 226,350 1.05 % 226,332 1.84 % 348,076 Total BOKF, NA 6,277,866 5,880,647 0.36 % Total other borrowed funds $ 6,277,866 $ 5,880,647 0.36 % As of Year Ended December 31, 2014 December 31, 2014 Balance Rate Average Balance Rate Maximum Parent company and other non-bank subsidiaries: Trust preferred debt $ — — % $ — — % $ — Other — — % — — % — Total other borrowings — — — % Subordinated debentures — — % — — % — Total parent company and other non-bank subsidiaries — — — % BOKF, NA: Funds purchased 57,031 0.05 % 494,220 0.07 % 1,548,676 Repurchase agreements 1,187,489 0.04 % 928,767 0.06 % 1,187,489 Other borrowings: Federal Home Loan Bank advances 2,103,400 0.25 % 1,894,966 0.24 % 3,453,400 GNMA repurchase liability 14,298 5.05 % 17,343 5.20 % 24,980 Other 16,076 2.73 % 16,433 2.32 % 16,582 Total other borrowings 2,133,774 1,928,742 0.35 % Subordinated debentures 347,983 2.35 % 347,892 2.50 % 347,983 Total BOKF, NA 3,726,277 3,699,621 0.43 % Total other borrowed funds $ 3,726,277 $ 3,699,621 0.43 %
Schedule of Maturities of Other Borrowings [Table Text Block]	Aggregate annual principal repayments at December 31, 2016 are as follows (in thousands): Parent Company and Other Non-bank Subsidiaries BOKF, NA 2017 $ — $ 5,549,587 2018 — 711 2019 — 956 2020 — 961 2021 — 965 Thereafter 152,949 11,173 Total $ 152,949 $ 5,564,353
Schedule of Repurchase Agreements [Table Text Block]	Additional information relating to securities sold under agreements to repurchase and related liabilities at December 31, 2016 and 2015 is as follows (dollars in thousands): December 31, 2016 Amortized Fair Repurchase Average Security Sold/Maturity Cost Value Liability 1 Rate U.S. government agency mortgage-backed securities: Overnight 1 $ 655,529 $ 655,851 $ 668,661 0.02 % Long-term — — — — % Total Agency Securities $ 655,529 $ 655,851 $ 668,661 0.02 % December 31, 2015 Amortized Fair Repurchase Average Security Sold/Maturity Cost Value Liability 1 Rate U.S. government agency mortgage-backed securities: Overnight 1 $ 685,458 $ 688,485 $ 722,444 0.02 % Long-term — — — — % Total Agency Securities $ 685,458 $ 688,485 $ 722,444 0.02 % 1 BOK Financial maintains control over the securities underlying overnight repurchase agreements and generally transfers control over securities underlying longer-term dealer repurchase agreements to the respective counterparty.

Federal and State Income Taxes

Federal and State Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Schedule of Deferred Tax Assets and Liabilities [Table Text Block]	Deferred income taxes reflect the net tax effects of temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes. Significant components of deferred tax assets and liabilities are as follows (in thousands): December 31, 2016 2015 Deferred tax assets: Available for sale securities mark to market $ 5,779 $ — Share-based compensation 9,360 10,522 Credit loss allowances 99,191 88,906 Valuation adjustments 12,222 6,957 Deferred compensation 30,262 25,950 Unearned fees 11,877 11,124 Other 42,541 34,169 Total deferred tax assets 211,232 177,628 Deferred tax liabilities: Available for sale securities mark to market — 14,828 Depreciation 25,877 22,080 Mortgage servicing rights 92,748 77,900 Lease financing 17,923 22,301 Other 45,363 41,904 Total deferred tax liabilities 181,911 179,013 Net deferred tax assets (liabilities) $ 29,321 $ (1,385 )
Schedule of Components of Income Tax Expense (Benefit) [Table Text Block]	The significant components of the provision for income taxes attributable to continuing operations for BOK Financial are shown below (in thousands): Year Ended December 31, 2016 2015 2014 Current income tax expense: Federal $ 107,379 $ 117,566 $ 95,289 State 11,028 12,397 9,392 Total current income tax expense 118,407 129,963 104,681 Deferred income tax expense: Federal (11,340 ) 8,397 36,521 State (690 ) 1,024 2,949 Total deferred income tax expense (12,030 ) 9,421 39,470 Total income tax expense $ 106,377 $ 139,384 $ 144,151
Schedule of Effective Income Tax Rate Reconciliation [Table Text Block]	The reconciliations of income attributable to continuing operations at the U.S. federal statutory tax rate to income tax expense are as follows (in thousands): Year Ended December 31, 2016 2015 2014 Amount: Federal statutory tax $ 118,530 $ 151,075 $ 153,870 Tax exempt revenue (10,544 ) (9,553 ) (8,446 ) Effect of state income taxes, net of federal benefit 6,478 9,082 9,054 Utilization of tax credits: Low-income housing tax credits, net of amortization (4,171 ) (3,874 ) (2,953 ) Other tax credits (2,085 ) (2,085 ) (2,109 ) Bank-owned life insurance (2,911 ) (3,264 ) (3,183 ) Other, net 1,080 (1,997 ) (2,082 ) Total income tax expense $ 106,377 $ 139,384 $ 144,151 Year Ended December 31, 2016 2015 2014 Percent of pretax income: Federal statutory tax 35.0 % 35.0 % 35.0 % Tax exempt revenue (3.1 ) (2.2 ) (1.9 ) Effect of state income taxes, net of federal benefit 1.9 2.1 2.1 Utilization of tax credits: Low-income housing tax credits, net of amortization (1.2 ) (0.9 ) (0.7 ) Other tax credits (0.6 ) (0.5 ) (0.5 ) Bank-owned life insurance (0.9 ) (0.7 ) (0.7 ) Other, net 0.3 (0.5 ) (0.5 ) Total 31.4 % 32.3 % 32.8 %
Schedule of Unrecognized Tax Benefits Roll Forward [Table Text Block]	A reconciliation of the beginning and ending amount of unrecognized tax benefits is as follows (in thousands): 2016 2015 2014 Balance as of January 1 $ 13,232 $ 13,374 $ 12,058 Additions for tax for current year positions 5,640 2,226 3,813 Settlements during the period — — — Lapses of applicable statute of limitations (3,031 ) (2,368 ) (2,497 ) Balance as of December 31 $ 15,841 $ 13,232 $ 13,374

Employee Benefits (Tables)

Employee Benefits (Tables)	12 Months Ended
	Dec. 31, 2016
Compensation and Retirement Disclosure [Abstract]
Change in benefit obligation, plan assets funded status and net periodic pension cost (benefit) [Table Text Block]	The following table presents information regarding this plan (in thousands): December 31, 2016 2015 Change in projected benefit obligation: Projected benefit obligation at beginning of year $ 38,797 $ 45,224 Interest cost 1,309 1,487 Actuarial loss (gain) (55 ) (2,702 ) Benefits paid (5,087 ) (5,212 ) Projected benefit obligation at end of year 1,2 $ 34,964 $ 38,797 Change in plan assets: Plan assets at fair value at beginning of year $ 44,190 $ 49,443 Actual return on plan assets 2,666 (41 ) Benefits paid (5,087 ) (5,212 ) Plan assets at fair value at end of year $ 41,769 $ 44,190 Funded status of the plan $ 6,805 $ 5,393 Components of net periodic benefit costs: Interest cost $ 1,309 $ 1,487 Expected return on plan assets (2,167 ) (2,706 ) Other (741 ) 1,849 Net benefit cost $ (1,599 ) $ 630 1 Projected benefit obligation equals accumulated benefit obligation. 2 Projected benefit obligation is based on January 1 measurement date.
Valuation assumptions used [Table Text Block]	Weighted-average assumptions as of December 31: 2016 2015 Discount rate 3.43 % 3.54 % Expected return on plan assets 5.00 % 5.00 %
Expected future benefit payments [Table Text Block]	As of December 31, 2016 , expected future benefit payments related to the Pension Plan were as follows (in thousands): 2017 $ 2,706 2018 3,072 2019 3,402 2020 3,090 2021 2,934 Thereafter 28,044 Total estimated future benefit payments $ 43,248

Share-Based Compensation Plans

Share-Based Compensation Plans (Tables)	12 Months Ended
	Dec. 31, 2016
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Schedule of Share-based Compensation, Stock Options, Activity [Table Text Block]	The following table presents stock options outstanding during 2016 , 2015 and 2014 under these plans (in thousands, except for per share data): Number Weighted- Average Exercise Price Aggregate Intrinsic Value Options outstanding at December 31, 2013 1,135,105 $ 49.09 $ 19,564 Options awarded — — Options exercised (323,004 ) 49.17 Options forfeited (15,509 ) 45.71 Options expired (2,701 ) 47.98 Options outstanding at December 31, 2014 793,891 49.05 8,725 Options awarded — — Options exercised (286,678 ) 47.86 Options forfeited (22,304 ) 48.90 Options expired (4,874 ) 51.32 Options outstanding at December 31, 2015 480,035 49.75 4,821 Options awarded — — Options exercised (249,404 ) 47.60 Options forfeited (4,098 ) 55.44 Options expired (8,009 ) 53.43 Options outstanding at December 31, 2016 218,524 $ 51.95 $ 6,793 Options vested at: December 31, 2014 347,633 $ 48.85 $ 3,889 December 31, 2015 243,395 48.17 2,829 December 31, 2016 93,117 46.22 3,429
Schedule of Share-based Compensation, Outstanding and Vested Stock Options [Table Text Block]	The following table summarizes information concerning currently outstanding and vested stock options: Options Outstanding Options Vested Weighted Weighted Average Weighted Weighted Average Remaining Average Average Remaining Exercise Number Contractual Exercise Number Exercise Contractual Prices Outstanding Life (years) Price Vested Price Life (years) $36.65 36,722 1.45 $36.65 36,722 $36.65 1.45 48.30 14,208 2.32 48.30 6,906 48.30 1.57 48.46 21,138 0.81 48.46 21,138 48.46 0.81 54.33 3,628 0.03 54.33 3,628 54.33 0.03 55.74 51,570 4.28 55.74 5,008 55.74 2.03 55.94 48,800 3.08 55.94 12,260 55.94 1.72 58.76 42,458 3.62 58.76 7,455 58.76 1.70
Schedule of Nonvested Share Activity [Table Text Block]	The following represents a summary of the non-vested stock awards as of December 31, 2016 (in thousands): Shares Weighted Average Grant Date Fair Value Non-vested at January 1, 2014 647,989 Granted 206,621 $64.96 Vested (140,820 ) $44.56 Forfeited (25,179 ) $56.26 Non-vested at December 31, 2014 688,611 Granted 312,755 $57.66 Vested (114,045 ) $50.15 Forfeited (96,212 ) $58.33 Non-vested at December 31, 2015 791,109 Granted 256,670 $55.35 Vested (213,941 ) $55.87 Forfeited (47,132 ) $57.86 Non-vested at December 31, 2016 786,706

Related Parties Related Parties

Related Parties Related Parties (Tables)	12 Months Ended
	Dec. 31, 2016
Related Party Transactions [Abstract]
Schedule of Related Party Transactions [Table Text Block]	Activity in loans to related parties is summarized as follows (in thousands): Year Ended December 31, 2016 2015 Beginning balance $ 594,225 $ 103,395 Advances 884,511 3,582,384 Payments (1,123,747 ) (3,104,004 ) Adjustments 1 (218,044 ) 12,450 Ending balance $ 136,945 $ 594,225 1 Adjustments generally consist of changes in status as a related party.

Commitments and Contingent Li42

Commitments and Contingent Liabilities Variable Interest Entities (Tables)	12 Months Ended
	Dec. 31, 2016
Commitments and Contingencies Disclosure [Abstract]
Schedule of Variable Interest Entities [Table Text Block]	December 31, 2016 Loans Other Assets Other Liabilities Other Borrowings Non-controlling Interests Consolidated: Private equity funds $ — $ 17,357 $ — $ — $ 13,237 Tax credit entities 10,000 11,585 — 10,964 10,000 Other — 29,783 3,189 1,092 8,266 Total consolidated $ 10,000 $ 58,725 $ 3,189 $ 12,056 $ 31,503 Unconsolidated: Tax credit entities $ 44,488 $ 143,715 $ 63,329 $ — $ — Other — 31,675 15,028 — — Total unconsolidated $ 44,488 $ 175,390 $ 78,357 $ — $ — December 31, 2015 Loans Other Other Other Non-controlling Consolidated: Private equity funds $ — $ 22,472 $ — $ — $ 17,823 Tax credit entities 10,000 12,206 — 10,964 10,000 Other — 40,453 2,198 2,831 9,260 Total consolidated $ 10,000 $ 75,131 $ 2,198 $ 13,795 $ 37,083 Unconsolidated: Tax credit entities $ 16,916 $ 85,274 $ 14,572 $ — $ — Other — 15,506 6,319 — — Total unconsolidated $ 16,916 $ 100,780 $ 20,891 $ — $ —

Earnings Per Share (Tables)

Earnings Per Share (Tables)	12 Months Ended
	Dec. 31, 2016
Earnings Per Share [Abstract]
Earnings Per Share [Table Text Block]	The following table presents the computation of basic and diluted earnings per share (dollars in thousands, except per share data): Year Ended 2016 2015 2014 Numerator: Net income attributable to BOK Financial Corp. shareholders $ 232,668 $ 288,565 $ 292,435 Less: Earnings allocated to participating securities 2,883 3,383 3,239 Numerator for basic earnings per share – income available to common shareholders 229,785 285,182 289,196 Effect of reallocating undistributed earnings of participating securities 1 3 4 Numerator for diluted earnings per share – income available to common shareholders $ 229,786 $ 285,185 $ 289,200 Denominator: Weighted average shares outstanding 65,901,110 68,397,215 69,159,902 Less: Participating securities included in weighted average shares outstanding 815,483 802,526 765,708 Denominator for basic earnings per common share 65,085,627 67,594,689 68,394,194 Dilutive effect of employee stock compensation plans 1 58,271 96,969 150,576 Denominator for diluted earnings per common share 65,143,898 67,691,658 68,544,770 Basic earnings per share $ 3.53 $ 4.22 $ 4.23 Diluted earnings per share $ 3.53 $ 4.21 $ 4.22 1 Excludes employee stock options with exercise prices greater than current market price. — — —

Shareholders' Equity (Tables)

Shareholders' Equity (Tables)	12 Months Ended
	Dec. 31, 2016
Stockholders' Equity Note [Abstract]
Summary of Regulatory Capital Levels [Table Text Block]	A summary of regulatory capital minimum requirements and levels follows (dollars in thousands): Minimum Capital Requirement Capital Conservation Buffer 1 Minimum Capital Requirement Including Capital Conservation Buffer December 31, 2016 December 31, 2015 Common equity Tier 1 Capital (to Risk Weighted Assets): Consolidated 4.50% 2.50% 7.00% 2,834,532 11.21 % $ 2,842,193 12.13 % BOKF, NA 4.50% N/A 4.50% 2,609,450 10.65 % 2,385,323 10.26 % Mobank 2 4.50% N/A 4.50% 54,616 10.03 % N/A N/A Tier I Capital (to Risk Weighted Assets): Consolidated 6.00% 2.50% 8.50% $ 2,834,532 11.21 % $ 2,842,193 12.13 % BOKF, NA 6.00% N/A 6.00% 2,609,450 10.65 % 2,385,323 10.26 % Mobank 2 6.00% N/A 6.00% 54,616 10.03 % N/A N/A Total Capital (to Risk Weighted Assets): Consolidated 8.00% 2.50% 10.50% $ 3,238,323 12.81 % $ 3,116,144 13.30 % BOKF, NA 8.00% N/A 8.00% 2,866,949 11.70 % 2,657,935 11.43 % Mobank 2 8.00% N/A 8.00% 54,617 10.03 % N/A N/A Leverage (Tier I Capital to Average Assets): Consolidated 4.00% N/A 4.00% $ 2,834,532 8.72 % $ 2,842,193 9.25 % BOKF, NA 4.00% N/A 4.00% 2,609,450 8.11 % 2,385,323 7.81 % Mobank 2 4.00% N/A 4.00% 54,616 8.37 % N/A N/A 1 Capital conservation buffer is effective January 1, 2016 and is phased in through 2019. The phased in capital conservation buffer at December 31, 2016 is 0.625% . The fully phased in requirement of 2.50% is included in the table above. 2 Missouri Bank and Trust Company of Kansas City dba Mobank was acquired by BOK Financial effective December 1, 2016.
Accumulated Other Comprehensive Income (Loss) [Table Text Block]	A rollforward of the components of accumulated other comprehensive income (loss) is included as follows (in thousands): Unrealized Gain (Loss) on Available for Sale Securities Investment Securities Transferred from AFS Employee Benefit Plans Loss on Effective Cash Flow Hedges Total Balance, December 31, 2013 $ (23,175 ) $ 1,118 $ (3,311 ) $ (255 ) $ (25,623 ) Net change in unrealized gain (loss) 136,050 — 725 — 136,775 Reclassification adjustments included in earnings: Interest revenue, Investment securities, Taxable securities — (1,216 ) — — (1,216 ) Interest expense, Subordinated debentures — — — 296 296 Net impairment losses recognized in earnings 373 — — — 373 Gain on available for sale securities, net (1,539 ) — — — (1,539 ) Other comprehensive income (loss), before income taxes 134,884 (1,216 ) 725 296 134,689 Federal and state income tax 1 52,470 (474 ) 282 115 52,393 Other comprehensive income (loss), net of income taxes 82,414 (742 ) 443 181 82,296 Balance, December 31, 2014 59,239 376 (2,868 ) (74 ) 56,673 Net change in unrealized gain (loss) (48,607 ) — 1,804 — (46,803 ) Reclassification adjustments included in earnings: Interest revenue, Investment securities, Taxable securities — (503 ) — — (503 ) Interest expense, Subordinated debentures — — — 121 121 Net impairment losses recognized in earnings 1,819 — — — 1,819 Gain on available for sale securities, net (12,058 ) — — — (12,058 ) Other comprehensive income (loss), before income taxes (58,846 ) (503 ) 1,804 121 (57,424 ) Federal and state income tax 1 (22,891 ) (195 ) 701 47 (22,338 ) Other comprehensive income (loss), net of income taxes (35,955 ) (308 ) 1,103 74 (35,086 ) Balance, December 31, 2015 23,284 68 (1,765 ) — 21,587 Net change in unrealized gain (loss) (41,333 ) — (188 ) — (41,521 ) Reclassification adjustments included in earnings: Interest revenue, Investment securities, Taxable securities — (112 ) — — (112 ) Interest expense, Subordinated debentures — — — — — Net impairment losses recognized in earnings — — — — — Gain on available for sale securities, net (11,675 ) — — — (11,675 ) Other comprehensive income (loss), before income taxes (53,008 ) (112 ) (188 ) — (53,308 ) Federal and state income tax 1 (20,637 ) (44 ) (73 ) — (20,754 ) Other comprehensive income (loss), net of income taxes (32,371 ) (68 ) (115 ) — (32,554 ) Balance, December 31, 2016 $ (9,087 ) $ — $ (1,880 ) $ — $ (10,967 ) 1 Calculated using 39% effective tax rate.

Reportable Segments (Tables)

Reportable Segments (Tables)	12 Months Ended
	Dec. 31, 2016
Segment Reporting [Abstract]
Reportable Segments [Table Text Block]	Reportable segments reconciliation to the Consolidated Financial Statements for the year ended December 31, 2016 is as follows (in thousands): Commercial Consumer Wealth Management Funds Management and Other BOK Financial Consolidated Net interest and dividend revenue from external sources $ 492,967 $ 85,998 $ 33,006 $ 135,257 $ 747,228 Net interest revenue (expense) from internal sources (58,781 ) 37,777 29,043 (8,039 ) — Net interest and dividend revenue 434,186 123,775 62,049 127,218 747,228 Provision for credit losses 32,959 4,927 (801 ) 27,915 65,000 Net interest and dividend revenue after provision for credit losses 401,227 118,848 62,850 99,303 682,228 Other operating revenue 195,521 224,802 283,222 (29,525 ) 674,020 Other operating expense 216,451 249,744 250,994 300,401 1,017,590 Net direct contribution 380,297 93,906 95,078 (230,623 ) 338,658 Gain (loss) on financial instruments, net 10 (26,252 ) (42 ) 26,284 — Change in fair value of mortgage servicing rights — (2,193 ) — 2,193 — Gain (loss) on repossessed assets, net 669 979 — (1,648 ) — Corporate expense allocations 35,760 66,411 42,378 (144,549 ) — Net income before taxes 345,216 29 52,658 (59,245 ) 338,658 Federal and state income taxes 134,289 11 20,484 (48,407 ) 106,377 Net income 210,927 18 32,174 (10,838 ) 232,281 Net income (loss) attributable to non-controlling interests — — — (387 ) (387 ) Net income attributable to BOK Financial Corp. shareholders $ 210,927 $ 18 $ 32,174 $ (10,451 ) $ 232,668 Average assets $ 16,998,626 $ 8,722,372 $ 6,281,127 $ 276,277 $ 32,278,402 Reportable segments reconciliation to the Consolidated Financial Statements for the year ended December 31, 2015 is as follows (in thousands): Commercial Consumer Wealth Management Funds Management and Other BOK Financial Consolidated Net interest and dividend revenue from external sources $ 439,751 $ 84,848 $ 24,744 $ 154,011 $ 703,354 Net interest revenue (expense) from internal sources (52,313 ) 28,503 24,043 (233 ) — Net interest and dividend revenue 387,438 113,351 48,787 153,778 703,354 Provision for credit losses (6,748 ) 6,934 (1,083 ) 34,897 34,000 Net interest and dividend revenue after provision for credit losses 394,186 106,417 49,870 118,881 669,354 Other operating revenue 177,729 218,095 267,523 (4,867 ) 658,480 Other operating expense 202,804 203,070 228,664 261,653 896,191 Net direct contribution 369,111 121,442 88,729 (147,639 ) 431,643 Gain (loss) on financial instruments, net — (4,712 ) (204 ) 4,916 — Change in fair value of mortgage servicing rights — (4,853 ) — 4,853 — Gain (loss) on repossessed assets, net 708 916 — (1,624 ) — Corporate expense allocations 43,279 74,936 40,357 (158,572 ) — Net income before taxes 326,540 37,857 48,168 19,078 431,643 Federal and state income taxes 127,024 14,726 18,737 (21,103 ) 139,384 Net income 199,516 23,131 29,431 40,181 292,259 Net income attributable to non-controlling interests — — — 3,694 3,694 Net income attributable to BOK Financial Corp. shareholders $ 199,516 $ 23,131 $ 29,431 $ 36,487 $ 288,565 Average assets $ 16,284,527 $ 8,836,327 $ 5,444,483 $ 9,418 $ 30,574,755 Reportable segments reconciliation to the Consolidated Financial Statements for the year ended December 31, 2014 is as follows (in thousands): Commercial Consumer Wealth Management Funds Management and Other BOK Financial Consolidated Net interest and dividend revenue from external sources $ 382,331 $ 81,852 $ 23,817 $ 177,194 $ 665,194 Net interest revenue (expense) from internal sources (40,083 ) 26,813 20,959 (7,689 ) — Net interest and dividend revenue 342,248 108,665 44,776 169,505 665,194 Provision for credit losses (7,447 ) 5,477 213 1,757 — Net interest and dividend revenue after provision for credit losses 349,695 103,188 44,563 167,748 665,194 Other operating revenue 171,390 214,657 242,268 (6,357 ) 621,958 Other operating expense 195,706 207,131 218,000 226,685 847,522 Net direct contribution 325,379 110,714 68,831 (65,294 ) 439,630 Gain (loss) on financial instruments, net — 12,406 (235 ) (12,171 ) — Change in fair value of mortgage servicing rights — (16,445 ) — 16,445 — Gain (loss) on repossessed assets, net (3,187 ) 1,418 — 1,769 — Corporate expense allocations 45,502 64,531 38,731 (148,764 ) — Net income before taxes 276,690 43,562 29,865 89,513 439,630 Federal and state income taxes 107,632 16,946 11,617 7,956 144,151 Net income 169,058 26,616 18,248 81,557 295,479 Net income attributable to non-controlling interests — — — 3,044 3,044 Net income attributable to BOK Financial Corp. shareholders $ 169,058 $ 26,616 $ 18,248 $ 78,513 $ 292,435 Average assets $ 15,394,957 $ 8,373,317 $ 5,002,515 $ (771,931 ) $ 27,998,858

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2016
Fair Value Disclosures [Abstract]
Fair Value Assets And Liabilities Measured On A Recurring Basis [Table Text Block]	The fair value of financial assets and liabilities that are measured on a recurring basis is as follows as of December 31, 2016 (in thousands): Total Quoted Prices in Active Markets for Identical Instruments Significant Other Observable Inputs Significant Unobservable Inputs Assets: Trading securities: U.S. government agency debentures $ 6,234 $ — $ 6,234 $ — U.S. agency residential mortgage-backed securities 310,067 — 310,067 — Municipal and other tax-exempt securities 14,427 — 14,427 — Other trading securities 6,900 — 6,900 — Total trading securities 337,628 — 337,628 — Available for sale securities: U.S. Treasury securities 999 999 — — Municipal and other tax-exempt securities 40,993 — 35,204 5,789 U.S. government agency residential mortgage-backed securities 5,460,386 — 5,460,386 — Privately issued residential mortgage-backed securities 115,535 — 115,535 — Commercial mortgage-backed securities guaranteed by U.S. government agencies 3,017,933 — 3,017,933 — Other debt securities 4,152 — — 4,152 Perpetual preferred stock 18,474 — 18,474 — Equity securities and mutual funds 18,357 3,495 14,862 — Total available for sale securities 8,676,829 4,494 8,662,394 9,941 Fair value option securities – U.S. government agency residential mortgage-backed securities 77,046 — 77,046 — Residential mortgage loans held for sale 301,897 — 290,280 11,617 Mortgage servicing rights, net 1 247,073 — — 247,073 Derivative contracts, net of cash margin 2 689,872 7,541 682,331 — Liabilities: Derivative contracts, net of cash margin 2 664,531 6,972 657,559 — 1 A reconciliation of the beginning and ending fair value of mortgage servicing rights and disclosures of significant assumptions used to determine fair value are presented in Note 7 , Mortgage Banking Activities. 2 See Note 3 for detail of fair value of derivative contracts by contract type. Derivative contracts in a net asset position that were valued based on quoted prices in active markets or identical instruments (Level 1) are exchange-traded interest rate and energy derivative contracts, net of cash margin. Derivative contracts in a net liability position that were valued using quoted prices in active markets for identical instruments (Level 1) are exchange-traded interest rate, energy and agricultural derivative contracts, net of cash margin. The fair value of financial assets and liabilities that are measured on a recurring basis is as follows as of December 31, 2015 (in thousands): Total Quoted Prices in Active Markets for Identical Instruments Significant Other Observable Inputs Significant Unobservable Inputs Assets: Trading securities: U.S. government agency debentures $ 61,295 $ — $ 61,295 $ — U.S. government agency residential mortgage-backed securities 10,989 — 10,989 — Municipal and other tax-exempt securities 31,901 — 31,901 — Other trading securities 18,219 — 18,219 — Total trading securities 122,404 — 122,404 — Available for sale securities: U.S. Treasury securities 995 995 — — Municipal and other tax-exempt securities 56,817 — 47,207 9,610 U.S. government agency residential mortgage-backed securities 5,898,351 — 5,898,351 — Privately issued residential mortgage-backed securities 139,118 — 139,118 — Commercial mortgage-backed securities guaranteed by U.S. government agencies 2,905,796 — 2,905,796 — Other debt securities 4,151 — — 4,151 Perpetual preferred stock 19,672 — 19,672 — Equity securities and mutual funds 17,833 3,265 14,568 — Total available for sale securities 9,042,733 4,260 9,024,712 13,761 Fair value option securities – U.S. government agency residential mortgage-backed securities 444,217 — 444,217 — Residential mortgage loans held for sale 308,439 — 300,565 7,874 Mortgage servicing rights, net 1 218,605 — — 218,605 Derivative contracts, net of cash margin 2 586,270 38,530 547,740 — Liabilities: Derivative contracts, net of cash margin 2 581,701 — 581,701 — 1 A reconciliation of the beginning and ending fair value of mortgage servicing rights and disclosures of significant assumptions used to determine fair value are presented in Note 7 , Mortgage Banking Activities. 2 See Note 3 for detail of fair value of derivative contracts by contract type. Derivative contracts in a net asset position that were valued based on quoted prices in active markets for identical instruments (Level 1) are exchange-traded energy derivative contracts, net of cash margin. Derivative contracts in a net liability position that were valued using quoted prices in active markets for identical instruments based on quoted prices in active markets for identical instruments (Level 1) are exchange-traded interest rate and agricultural derivative contracts, fully offset by cash margin.
Fair Value Assets Measured On Recurring Basis Significant Unobservable Inputs [Table Text Block]	The following represents the changes related to assets measured at fair value on a recurring basis using significant unobservable inputs (in thousands): Available for Sale Securities Residential mortgage loans held for sale Municipal and other tax-exempt securities Other debt securities Balance, December 31, 2014 $ 10,093 $ 4,150 $ 11,856 Transfer to Level 3 from Level 2 1 — — 2,193 Purchases and capital calls — — — Redemptions and distributions — — — Proceeds from sales — — (6,283 ) Gain (loss) recognized in earnings: Mortgage banking revenue — — 108 Other comprehensive income (loss): Net change in unrealized gain (loss) (483 ) 1 — Balance, December 31, 2015 9,610 4,151 7,874 Transfer to Level 3 from Level 2 1 — — 6,631 Purchases and capital calls — — — Redemptions and distributions (3,975 ) — — Proceeds from sales — — (2,540 ) Gain (loss) recognized in earnings: Mortgage banking revenue — — (348 ) Other comprehensive income (loss): Net change in unrealized gain (loss) 154 1 — Balance, December 31, 2016 $ 5,789 $ 4,152 $ 11,617
Fair Value Inputs, Assets, Quantitative Information [Table Text Block]	A summary of quantitative information about Non-recurring Fair Value Measurements based on Significant Unobservable Inputs (Level 3) as of December 31, 2016 follows (in thousands): Quantitative Information about Level 3 Non-recurring Fair Value Measurements Fair Value Valuation Technique(s) Significant Unobservable Input Range (Weighted Average) Impaired loans $ 11,295 Appraised value, as adjusted Recoverable oil and gas reserves, forward-looking commodity prices and estimated operating costs 22% - 59% (57%) 1 Real estate and other repossessed assets 2,192 Appraised value, as adjusted Marketability adjustments off appraised value 2 70% - 87% (74%) 1 Represents fair value as a percentage of the unpaid principal balance. 2 Marketability adjustments include consideration of estimated costs to sell which is approximately 10% of the fair value. A summary of quantitative information about Non-recurring Fair Value Measurements based on Significant Unobservable Inputs (Level 3) as of December 31, 2015 follows (in thousands): Quantitative Information about Level 3 Non-recurring Fair Value Measurements Fair Value Valuation Technique(s) Significant Unobservable Input Range (Weighted Average) Impaired loans $ 20,805 Appraised value, as adjusted Broker quotes and management's knowledge of industry and collateral. N/A Real estate and other repossessed assets 245 Appraised value, as adjusted Marketability adjustments off appraised value 1 66%-81% (74%) 1 Marketability adjustments include consideration of estimated costs to sell which is approximately 10% of the fair value. A summary of quantitative information about assets measured at fair value on a recurring basis using significant unobservable inputs (Level 3) as of December 31, 2016 follows (in thousands): Quantitative Information about Level 3 Recurring Fair Value Measurements Par Value Amortized Cost/Unpaid Principal Balance Fair Value Valuation Technique(s) Significant Unobservable Input Range (Weighted Average) Available for sale securities: Municipal and other tax-exempt securities $ 6,195 $ 6,163 $ 5,712 Discounted cash flows 1 Interest rate spread 5.91%-6.21% (6.16%) 2 90.00%-93.40% (92.20%) 3 Other debt securities 4,400 4,400 4,152 Discounted cash flows 1 Interest rate spread 6.01% - 6.26% (6.23%) 4 94.34% - 94.36% (94.36%) 3 Residential mortgage loans held for sale N/A 12,431 11,617 Quoted prices of loans sold in securitization transactions, with a liquidity discount applied Liquidity discount applied to the market value of mortgage loans qualifying for sale to U.S. government agencies 93.45% 1 Discounted cash flows developed using discount rates primarily based on reference to interest rate spreads for comparable securities of similar duration and credit rating as determined by the nationally-recognized rating agencies, adjusted for lack of trading volume. 2 Interest rate yields used to value investment grade tax-exempt securities represent a spread of 467 to 525 basis points over average yields for comparable tax-exempt securities. 3 Represents fair value as a percentage of par value. 4 Interest rate yields used to value investment grade taxable securities based on comparable short-term taxable securities which are generally yielding approximately 1% . A summary of quantitative information about Recurring Fair Value Measurements based on Significant Unobservable Inputs (Level 3) as of December 31, 2015 follows (in thousands): Quantitative Information about Level 3 Recurring Fair Value Measurements Par Value Amortized Cost 6 Fair Value Valuation Technique(s) Significant Unobservable Input Range (Weighted Average) Available for sale securities: Municipal and other tax-exempt securities $ 10,370 $ 10,311 $ 9,610 Discounted cash flows 1 Interest rate spread 5.47%-5.77% (5.73%) 2 92.34%-92.93% (92.67%) 3 Other debt securities 4,400 4,400 4,151 Discounted cash flows 1 Interest rate spread 5.80% - 5.92% (5.90%) 4 94.33% - 94.34% (94.34%) 3 Residential mortgage loans held for sale N/A 8,395 7,874 Quoted prices of loans sold in securitization transactions, with a liquidity discount applied Liquidity discount applied to the market value of mortgage loans qualifying for sale to U.S. government agencies 93.79% 1 Discounted cash flows developed using discount rates primarily based on reference to interest rate spreads for comparable securities of similar duration and credit rating as determined by the nationally-recognized rating agencies, adjusted for lack of trading volume. 2 Interest rate yields used to value investment grade tax-exempt securities represent a spread of 499 to 541 basis points over average yields for comparable tax-exempt securities. 3 Represents fair value as a percentage of par value. 4 Interest rate yields used to value investment grade taxable securities based on comparable short-term taxable securities which are generally yielding less than 1% .
Fair Value Assets Measured on Nonrecurring Basis [Table Text Block]	The following represents the carrying value of assets measured at fair value on a non-recurring basis and related losses recorded during the year. The carrying value represents only those assets with the balance sheet date for which the fair value was adjusted during the year: Carrying Value at December 31, 2016 Fair Value Adjustments for the Quoted Prices in Active Markets for Identical Instruments Significant Other Observable Inputs Significant Unobservable Inputs Gross charge-offs against allowance for loan losses Net losses and expenses of repossessed assets, net Impaired loans $ — $ 539 $ 11,295 $ 7,594 $ — Real estate and other repossessed assets — 7,965 2,192 — 2,527 Carrying Value at December 31, 2015 Fair Value Adjustments for the Quoted Prices in Active Markets for Identical Instruments Significant Other Observable Inputs Significant Unobservable Inputs Gross charge-offs against allowance for loan losses Net losses and expenses of repossessed assets, net Impaired loans $ — $ 252 $ 20,805 $ 4,042 $ — Real estate and other repossessed assets — 13,611 245 — 1,820
Fair Value of Financial Instruments [Table Text Block]	The following table presents the carrying values and estimated fair values of all financial instruments, including those financial assets and liabilities that are not measured and reported at fair value on a recurring basis or non-recurring (dollars in thousands): December 31, 2016 Carrying Value Estimated Fair Value Quoted Prices in Active Markets for Identical Instruments (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Cash and due from banks $ 620,846 620,846 620,846 — — Interest-bearing cash and cash equivalents 1,916,651 1,916,651 1,916,651 — — Trading securities: U.S. government agency debentures 6,234 6,234 — 6,234 — U.S. government agency residential mortgage-backed securities 310,067 310,067 — 310,067 — Municipal and other tax-exempt securities 14,427 14,427 — 14,427 — Other trading securities 6,900 6,900 — 6,900 — Total trading securities 337,628 337,628 — 337,628 — Investment securities: Municipal and other tax-exempt securities 320,364 321,225 — 321,225 — U.S. government agency residential mortgage-backed securities 20,777 21,473 — 21,473 — Other debt securities 205,004 222,795 — 222,795 — Total investment securities 546,145 565,493 — 565,493 — Available for sale securities: U.S. Treasury securities 999 999 999 — — Municipal and other tax-exempt securities 40,993 40,993 — 35,204 5,789 U.S. government agency residential mortgage-backed securities 5,460,386 5,460,386 — 5,460,386 — Privately issued residential mortgage-backed securities 115,535 115,535 — 115,535 — Commercial mortgage-backed securities guaranteed by U.S. government agencies 3,017,933 3,017,933 — 3,017,933 — Other debt securities 4,152 4,152 — — 4,152 Perpetual preferred stock 18,474 18,474 — 18,474 — Equity securities and mutual funds 18,357 18,357 3,495 14,862 — Total available for sale securities 8,676,829 8,676,829 4,494 8,662,394 9,941 Fair value option securities – U.S. government agency residential mortgage-backed securities 77,046 77,046 — 77,046 — Residential mortgage loans held for sale 301,897 301,897 — 290,280 11,617 Loans: Commercial 10,390,824 10,437,016 — — 10,437,016 Commercial real estate 3,809,046 3,850,981 — — 3,850,981 Residential mortgage 1,949,832 2,025,159 — — 2,025,159 Personal 839,958 864,904 — — 864,904 Total loans 16,989,660 17,178,060 — — 17,178,060 Allowance for loan losses (246,159 ) — — — — Loans, net of allowance 16,743,501 17,178,060 — — 17,178,060 Mortgage servicing rights 247,073 247,073 — — 247,073 Derivative instruments with positive fair value, net of cash margin 689,872 689,872 7,541 682,331 — Deposits with no stated maturity 20,526,295 20,526,295 — — 20,526,295 Time deposits 2,221,800 2,218,303 — — 2,218,303 Other borrowed funds 5,572,662 5,556,327 — — 5,556,327 Subordinated debentures 144,640 128,903 — 128,903 — Derivative instruments with negative fair value, net of cash margin 664,531 664,531 6,972 657,559 — December 31, 2015 Carrying Value Estimated Fair Value Quoted Prices in Active Markets for Identical Instruments (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Cash and due from banks $ 573,699 $ 573,699 573,699 — $ — Interest-bearing cash and cash equivalents 2,069,900 2,069,900 2,069,900 — — Trading securities: U.S. government agency debentures 61,295 61,295 — 61,295 — U.S. government agency residential mortgage-backed securities 10,989 10,989 — 10,989 — Municipal and other tax-exempt securities 31,901 31,901 — 31,901 — Other trading securities 18,219 18,219 — 18,219 — Total trading securities 122,404 122,404 — 122,404 — Investment securities: Municipal and other tax-exempt securities 365,258 368,910 — 368,910 — U.S. government agency residential mortgage-backed securities 26,833 27,874 — 27,874 — Other debt securities 205,745 232,375 — 232,375 — Total investment securities 597,836 629,159 — 629,159 — Available for sale securities: U.S. Treasury securities 995 995 995 — — Municipal and other tax-exempt securities 56,817 56,817 — 47,207 9,610 U.S. government agency residential mortgage-backed securities 5,898,351 5,898,351 — 5,898,351 — Privately issued residential mortgage-backed securities 139,118 139,118 — 139,118 — Commercial mortgage-backed securities guaranteed by U.S. government agencies 2,905,796 2,905,796 — 2,905,796 — Other debt securities 4,151 4,151 — — 4,151 Perpetual preferred stock 19,672 19,672 — 19,672 — Equity securities and mutual funds 17,833 17,833 3,265 14,568 — Total available for sale securities 9,042,733 9,042,733 4,260 9,024,712 13,761 Fair value option securities – U.S. government agency residential mortgage-backed securities 444,217 444,217 — 444,217 — Residential mortgage loans held for sale 308,439 308,439 — 300,565 7,874 Loans: Commercial 10,252,531 10,053,952 — — 10,053,952 Commercial real estate 3,259,033 3,233,476 — — 3,233,476 Residential mortgage 1,876,893 1,902,976 — — 1,902,976 Personal 552,697 549,068 — — 549,068 Total loans 15,941,154 15,739,472 — — 15,739,472 Allowance for loan losses (225,524 ) — — — — Loans, net of allowance 15,715,630 15,739,472 — — 15,739,472 Mortgage servicing rights 218,605 218,605 — — 218,605 Derivative instruments with positive fair value, net of cash margin 586,270 586,270 38,530 547,740 — Deposits with no stated maturity 18,682,094 18,682,094 — — 18,682,094 Time deposits 2,406,064 2,394,562 — — 2,394,562 Other borrowed funds 6,051,515 5,600,932 — — 5,600,932 Subordinated debentures 226,350 223,758 — — 223,758 Derivative instruments with negative fair value, net of cash margin 581,701 581,701 — 581,701 —
Fair Value Inputs, Financial Instruments, Quantitative Information [Table Text Block]	Range of Contractual Yields Average Re-pricing (in years) Discount Rate Minimum Maximum Minimum Maximum December 31, 2016 Loans: Commercial 0.38 % 30.00 % 0.70 0.64 % 4.60 % Commercial real estate 0.38 % 18.00 % 0.71 0.94 % 4.27 % Residential mortgage 1.74 % 18.00 % 2.27 1.71 % 4.26 % Personal 0.25 % 21.00 % 0.40 1.03 % 4.59 % Time deposits 0.02 % 9.65 % 1.96 1.57 % 2.00 % Other borrowings 0.25 % 3.50 % 0.00 0.55 % 3.22 % Subordinated debentures 5.38 % 5.38 % 16.86 5.38 % 5.38 % December 31, 2015 Loans: Commercial 0.25 % 30.00 % 0.62 0.52 % 4.34 % Commercial real estate 0.38 % 18.00 % 0.73 0.95 % 3.93 % Residential mortgage 1.67 % 18.00 % 2.42 0.86 % 4.25 % Personal 0.38 % 21.00 % 0.37 1.19 % 4.11 % Time deposits 0.02 % 5.50 % 1.78 1.11 % 1.57 % Other borrowings 0.25 % 3.40 % 0.00 0.20 % 2.89 % Subordinated debentures 1.05 % 1.05 % 1.37 2.12 % 2.12 %

Parent Company Only Financial47

Parent Company Only Financial Statements Parent Company Only Financial Statements (Tables)	12 Months Ended
	Dec. 31, 2016
Condensed Financial Information of Parent Company Only Disclosure [Abstract]
Condensed Balance Sheet [Table Text Block]	Balance Sheets (In thousands) December 31, 2016 2015 Assets Cash and cash equivalents $ 163,418 $ 282,169 Available for sale securities 19,234 20,150 Investment in bank subsidiaries 3,067,595 2,746,810 Investment in non-bank subsidiaries 177,068 186,271 Other assets 4,865 1,534 Total assets $ 3,432,180 $ 3,236,934 Liabilities and Shareholders’ Equity Liabilities: Other liabilities $ 5,469 $ 6,378 Other borrowings – Trust preferred debt 7,217 — Subordinated debentures 144,640 — Total liabilities 157,326 6,378 Shareholders’ equity: Common stock 4 4 Capital surplus 1,006,535 982,009 Retained earnings 2,823,334 2,704,121 Treasury stock (544,052 ) (477,165 ) Accumulated other comprehensive income (loss) (10,967 ) 21,587 Total shareholders’ equity 3,274,854 3,230,556 Total liabilities and shareholders’ equity $ 3,432,180 $ 3,236,934
Condensed Income Statement [Table Text Block]	Statements of Earnings (In thousands) Year Ended December 31, 2016 2015 2014 Dividends, interest and fees received from bank subsidiaries $ 15,237 $ 150,308 $ 75,412 Dividends, interest and fees received from non-bank subsidiaries 25,923 — — Other revenue 1,612 1,279 1,572 Total revenue 42,772 151,587 76,984 Interest expense 4,182 131 293 Charitable contributions to BOKF Foundation — — 2,420 Professional fees and services 395 378 600 Other operating expense 1,583 1,864 1,556 Total expense 6,160 2,373 4,869 Income before taxes and equity in undistributed income of subsidiaries 36,612 149,214 72,115 Federal and state income taxes (1,920 ) (375 ) (1,702 ) Income before equity in undistributed income of subsidiaries 38,532 149,589 73,817 Equity in undistributed income of bank subsidiaries 216,120 134,045 214,435 Equity in undistributed income of non-bank subsidiaries (21,984 ) 4,931 4,183 Net income attributable to BOK Financial Corp. shareholders $ 232,668 $ 288,565 $ 292,435
Condensed Cash Flow Statement [Table Text Block]	Statements of Cash Flows (In thousands) Year Ended December 31, 2016 2015 2014 Cash Flows From Operating Activities: Net income $ 232,668 $ 288,565 $ 292,435 Adjustments to reconcile net income to net cash provided by operating activities: Equity in undistributed income of bank subsidiaries (216,120 ) (134,045 ) (214,435 ) Equity in undistributed income of non-bank subsidiaries 21,984 (4,931 ) (4,183 ) Tax effect from equity compensation, net (1,505 ) (925 ) (8,258 ) Change in other assets (2,933 ) 49 8,726 Change in other liabilities (1,285 ) (2,818 ) 1,055 Net cash provided by operating activities 32,809 145,895 75,340 Cash Flows From Investing Activities: Proceeds from sales of available for sale securities 1,632 4,760 — Investment in subsidiaries (26,000 ) (41,969 ) (15,336 ) Acquisitions, net of cash acquired (105,520 ) — — Net cash used in investing activities (129,888 ) (37,209 ) (15,336 ) Cash Flows From Financing Activities: Issuance of subordinated debentures, net of issuance costs 144,615 — — Issuance of common and treasury stock, net 12,455 6,711 4,472 Tax effect from equity compensation, net 1,505 925 8,258 Dividends paid (113,455 ) (115,281 ) (111,026 ) Repurchase of common stock (66,792 ) (229,540 ) (12,337 ) Net cash used in financing activities (21,672 ) (337,185 ) (110,633 ) Net decrease in cash and cash equivalents (118,751 ) (228,499 ) (50,629 ) Cash and cash equivalents at beginning of period 282,169 510,668 561,297 Cash and cash equivalents at end of period $ 163,418 $ 282,169 $ 510,668 Cash paid for interest $ 4,127 $ 131 $ 293 Issuance of shares in settlement of deferred compensation, net $ — $ — $ 8,352

Significant Accounting Polici48

Significant Accounting Policies Reclassification (Details) $ in Millions	12 Months Ended
	Dec. 31, 2015USD ($)
Accounting Policies [Abstract]
Prior Period Reclassification Adjustment	$ 8.4

Significant Accounting Polici49

Significant Accounting Policies Goodwill and Intangible Assets (Details)	12 Months Ended
	Dec. 31, 2016
Minimum [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life	3 years
Maximum [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life	20 years

Significant Accounting Polici50

Significant Accounting Policies Cash Equivalents (Details)	12 Months Ended
	Dec. 31, 2016
Cash and Cash Equivalents [Abstract]
Maturity of Federal Funds Sold Considered Cash Equivalents	1 day
Maturity of Resell Agreement Considered Cash Equivalents, Minimum	1 day
Maturity of Resell Agreements Considered Cash Equivalents, Maximum	30 days

Significant Accounting Polici51

Significant Accounting Policies Loans (Details)	12 Months Ended
	Dec. 31, 2016
Loans [Abstract]
Loans, Number of Days Past Due for a Non-Risk Graded Loan to be Placed on Nonaccruing Status	90 days
Loans, Number of Days After Notification of Chapter 7 Bankruptcy Non-Risk Graded Loan is Placed on Nonaccruing Status	60 days
Loans, Minimum Number of Days After Which Past Due Non-Risk Graded Loans Are Charged Off	60 days
Loans, Maximum Number of Days After Which Past Due Non-Risk Graded Loans Are Charged Off	180 days
Loans, Number of Days After Notification of Chapter 7 Bankruptcy Non-Risk Graded Loan is Charged Off	60 days

Significant Accounting Polici52

Significant Accounting Policies Premises and Equipment (Details)	12 Months Ended
	Dec. 31, 2016
Buildings and improvements | Minimum [Member]
Premises and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	5 years
Buildings and improvements | Maximum [Member]
Premises and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	40 years
Software and Software Development Costs [Member] | Minimum [Member]
Premises and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	3 years
Software and Software Development Costs [Member] | Maximum [Member]
Premises and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	10 years
Furniture and equipment | Minimum [Member]
Premises and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	3 years
Furniture and equipment | Maximum [Member]
Premises and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	10 years

Significant Accounting Polici53

Significant Accounting Policies Share-Based Compensation (Details)	12 Months Ended
	Dec. 31, 2016
Stock Options [Member]
Share-based Compensation Arrangements by Share-based Payment Award [Line Items]
Vesting period (in years)	7 years
Prior to 2013 [Member] | Non-vested Common Stock [Member]
Share-based Compensation Arrangements by Share-based Payment Award [Line Items]
Vesting period (in years)	5 years
2013 and Beyond Plan [Member] | Non-vested Common Stock [Member]
Share-based Compensation Arrangements by Share-based Payment Award [Line Items]
Vesting period (in years)	3 years
Share-based Compensation Arrangement by Share-based Payment Award, Award Required Holding Period	2 years

Significant Accounting Polici54

Significant Accounting Policies Newly Adopted and Pending Accounting Pronouncements (Details)	12 Months Ended
	Dec. 31, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Percentage of gross revenue of Transaction Card Revenue and Fiduciary and Asset Management Revenue	18.00%
Percentage of fees and commission revenue composed of Transaction Card Revenue and Fiduciary and Asset Management Revenue	39.00%

Trading Securities (Details)

Trading Securities (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Schedule of Trading Securities [Line Items]
Trading Securities, Fair Value	$ 337,628	$ 122,404
Trading Securities, Net Unrealized Gain (Loss)	738	140
U.S. government agency debentures [Member]
Schedule of Trading Securities [Line Items]
Trading Securities, Fair Value	6,234	61,295
Trading Securities, Net Unrealized Gain (Loss)	(4)	(71)
U.S. government agency residential mortgage-backed securities [Member]
Schedule of Trading Securities [Line Items]
Trading Securities, Fair Value	310,067	10,989
Trading Securities, Net Unrealized Gain (Loss)	635	17
Municipal and other tax-exempt securities [Member]
Schedule of Trading Securities [Line Items]
Trading Securities, Fair Value	14,427	31,901
Trading Securities, Net Unrealized Gain (Loss)	50	210
Other trading securities [Member]
Schedule of Trading Securities [Line Items]
Trading Securities, Fair Value	6,900	18,219
Trading Securities, Net Unrealized Gain (Loss)	$ 57	$ (16)

Investment (Held-to-Maturity) S

Investment (Held-to-Maturity) Securities (Details) $ in Thousands		12 Months Ended
		Dec. 31, 2016USD ($)		Dec. 31, 2015USD ($)
Schedule of Investment (Held-to-Maturity) Securities [Line Items]
Investment Securities, Amortized Cost		$ 546,145		$ 597,724
Investment Securities, Debt Maturities, Carrying Value		546,145		597,836
Investment Securities, Fair Value		565,493		629,159
Investment Securities, Gross Unrealized Gain		21,154	[1]	31,687	[2]
Investment Securities, Gross Unrealized Loss		(1,806)	[1]	(364)	[2]
Investment Securities, Debt Maturities, Carrying Value [Abstract]
Investment Securities, Debt Maturities, Carrying Value		546,145		597,836
Investment Securities, Debt Maturities, Fair Value, Rolling Maturity [Abstract]
Investment Securities, Fair Value		$ 565,493		629,159
Investment Securities, Debt Maturities, Nominal Yield [Abstract]
Investment Securities, Debt Maturities, Nominal Yield		3.56%
Investment Securities, Pledged as Collateral [Abstract]
Investment Securities, Pledged as Collateral, Carrying Value		$ 322,208		231,033
Investment Securities, Pledged as Collateral, Fair Value		$ 323,808		$ 234,382
Investment Securities, Continuous Unrealized Loss Position, Qualitative Disclosure [Abstract]
Investment Securities, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Securities		193		85
Investment Securities, Continuous Unrealized Loss Position, Fair Value [Abstract]
Investment Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value		$ 236,070		$ 133,934
Investment Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		5,188		15,095
Investment Securities, Continuous Unrealized Loss Position, Fair Value		241,258		149,029
Investment Securities, Continuous Unrealized Loss Position, Aggregate Losses [Abstract]
Investment Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Losses		1,709		269
Investment Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Losses		97		95
Investment Securities, Continuous Unrealized Loss Position, Accumulated Loss		1,806		364
Other than Temporary Impairment Losses, Investment Securities, Portion Recognized in Earnings, Net, Qualitative Disclosures, Lowest Current Credit Rating [Abstract]
Investment Securities, Portfolio Concentration Rated AAA to AA, Carrying Value		334,115
Investment Securities, Portfolio Concentration Rated AAA to AA, Fair Value		350,475
Investment Securities, Portfolio Concentration Rated A to BBB, Carrying Value		6,028
Investment Securities, Portfolio Concentration Rated A to BBB, Fair Value		6,037
Investment Securities, Portfolio Concentration Rated Below Investment Grade, Carrying Value		0
Investment Securities, Portfolio Concentration Rated Below Investment Grade, Fair Value		0
Investment Securities, Portfolio Concentration Not Rated, Carrying Value		206,002
Investment Securities, Portfolio Concentration Not Rated, Fair Value		208,981
Fixed maturity securities [Member]
Investment Securities, Debt Maturities, Carrying Value [Abstract]
Investment Securities, Debt Maturities, Less than One Year, Carrying Value		99,628
Investment Securities, Debt Maturities, One to Five Years, Carrying Value		223,400
Investment Securities, Debt Maturities, Six to Ten Years, Carrying Value		133,229
Investment Securities, Debt Maturities, Over Ten Years, Carrying Value		69,111
Held-to-maturity Securities, Debt Maturities, Single Maturity Date, Carrying Value		525,368
Investment Securities, Debt Maturities, Fair Value, Rolling Maturity [Abstract]
Investment Securities, Debt Maturities, Less than One Year, Fair Value		99,651
Investment Securities, Debt Maturities, One to Five Years, Fair Value		225,365
Investment Securities, Debt Maturities, Six to Ten Years, Fair Value		147,846
Investment Securities, Debt Maturities, Over Ten Years, Fair Value		71,158
Investment Securities, Debt Maturities, Single Maturity Date, Fair value		$ 544,020
Investment Securities, Debt Maturities, Nominal Yield [Abstract]
Investment Securities, Debt Maturities, Less Than One Year, Nominal Yield		1.77%
Investment Securities, Debt Maturities, One to Five Years, Nominal Yield		2.65%
Investment Securities, Debt Maturities, Six to Ten Years, Nominal Yield		5.75%
Investment Securities, Debt Maturities, Over Ten Years, Nominal Yield		5.08%
Investment Securities, Debt Maturities, Nominal Yield		3.59%
Investment Securities, Debt Maturities, Weighted Average Maturity	[3]	4.68
Municipal and other tax-exempt securities [Member]
Schedule of Investment (Held-to-Maturity) Securities [Line Items]
Investment Securities, Amortized Cost		$ 320,364		365,258
Investment Securities, Debt Maturities, Carrying Value		320,364		365,258
Investment Securities, Fair Value		321,225		368,910
Investment Securities, Gross Unrealized Gain		2,272	[1]	3,935	[2]
Investment Securities, Gross Unrealized Loss		(1,411)	[1]	(283)	[2]
Investment Securities, Debt Maturities, Carrying Value [Abstract]
Investment Securities, Debt Maturities, Less than One Year, Carrying Value		83,583
Investment Securities, Debt Maturities, One to Five Years, Carrying Value		181,596
Investment Securities, Debt Maturities, Six to Ten Years, Carrying Value		5,909
Investment Securities, Debt Maturities, Over Ten Years, Carrying Value		49,276
Held-to-maturity Securities, Debt Maturities, Single Maturity Date, Carrying Value		320,364
Investment Securities, Debt Maturities, Carrying Value		320,364		365,258
Investment Securities, Debt Maturities, Fair Value, Rolling Maturity [Abstract]
Investment Securities, Debt Maturities, Less than One Year, Fair Value		83,544
Investment Securities, Debt Maturities, One to Five Years, Fair Value		180,993
Investment Securities, Debt Maturities, Six to Ten Years, Fair Value		5,836
Investment Securities, Debt Maturities, Over Ten Years, Fair Value		50,852
Investment Securities, Debt Maturities, Single Maturity Date, Fair value		321,225
Investment Securities, Fair Value		$ 321,225		$ 368,910
Investment Securities, Debt Maturities, Nominal Yield [Abstract]
Investment Securities, Debt Maturities, Less Than One Year, Nominal Yield	[4]	1.48%
Investment Securities, Debt Maturities, One to Five Years, Nominal Yield	[4]	2.08%
Investment Securities, Debt Maturities, Six to Ten Years, Nominal Yield	[4]	3.31%
Investment Securities, Debt Maturities, Over Ten Years, Nominal Yield	[4]	5.20%
Investment Securities, Debt Maturities, Nominal Yield	[4]	2.43%
Investment Securities, Debt Maturities, Weighted Average Maturity	[3]	3.41
Investment Securities, Debt Maturities, Effective tax rate for nominal yield calculation		39.00%
Investment Securities, Continuous Unrealized Loss Position, Qualitative Disclosure [Abstract]
Investment Securities, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Securities		151		73
Investment Securities, Continuous Unrealized Loss Position, Fair Value [Abstract]
Investment Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value		$ 219,892		$ 127,319
Investment Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		4,333		13,380
Investment Securities, Continuous Unrealized Loss Position, Fair Value		224,225		140,699
Investment Securities, Continuous Unrealized Loss Position, Aggregate Losses [Abstract]
Investment Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Losses		1,316		206
Investment Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Losses		95		77
Investment Securities, Continuous Unrealized Loss Position, Accumulated Loss		1,411		283
Other than Temporary Impairment Losses, Investment Securities, Portion Recognized in Earnings, Net, Qualitative Disclosures, Lowest Current Credit Rating [Abstract]
Investment Securities, Portfolio Concentration Rated AAA to AA, Carrying Value		193,931
Investment Securities, Portfolio Concentration Rated AAA to AA, Fair Value		193,834
Investment Securities, Portfolio Concentration Rated A to BBB, Carrying Value		6,028
Investment Securities, Portfolio Concentration Rated A to BBB, Fair Value		6,037
Investment Securities, Portfolio Concentration Rated Below Investment Grade, Carrying Value		0
Investment Securities, Portfolio Concentration Rated Below Investment Grade, Fair Value		0
Investment Securities, Portfolio Concentration Not Rated, Carrying Value		120,405
Investment Securities, Portfolio Concentration Not Rated, Fair Value		121,354
Other debt securities [Member]
Schedule of Investment (Held-to-Maturity) Securities [Line Items]
Investment Securities, Amortized Cost		205,004		205,745
Investment Securities, Debt Maturities, Carrying Value		205,004		205,745
Investment Securities, Fair Value		222,795		232,375
Investment Securities, Gross Unrealized Gain		18,115	[1]	26,689	[2]
Investment Securities, Gross Unrealized Loss		(324)	[1]	(59)	[2]
Investment Securities, Debt Maturities, Carrying Value [Abstract]
Investment Securities, Debt Maturities, Less than One Year, Carrying Value		16,045
Investment Securities, Debt Maturities, One to Five Years, Carrying Value		41,804
Investment Securities, Debt Maturities, Six to Ten Years, Carrying Value		127,320
Investment Securities, Debt Maturities, Over Ten Years, Carrying Value		19,835
Held-to-maturity Securities, Debt Maturities, Single Maturity Date, Carrying Value		205,004
Investment Securities, Debt Maturities, Carrying Value		205,004		205,745
Investment Securities, Debt Maturities, Fair Value, Rolling Maturity [Abstract]
Investment Securities, Debt Maturities, Less than One Year, Fair Value		16,107
Investment Securities, Debt Maturities, One to Five Years, Fair Value		44,372
Investment Securities, Debt Maturities, Six to Ten Years, Fair Value		142,010
Investment Securities, Debt Maturities, Over Ten Years, Fair Value		20,306
Investment Securities, Debt Maturities, Single Maturity Date, Fair value		222,795
Investment Securities, Fair Value		$ 222,795		$ 232,375
Investment Securities, Debt Maturities, Nominal Yield [Abstract]
Investment Securities, Debt Maturities, Less Than One Year, Nominal Yield		3.28%
Investment Securities, Debt Maturities, One to Five Years, Nominal Yield		5.14%
Investment Securities, Debt Maturities, Six to Ten Years, Nominal Yield		5.86%
Investment Securities, Debt Maturities, Over Ten Years, Nominal Yield		4.79%
Investment Securities, Debt Maturities, Nominal Yield		5.41%
Investment Securities, Debt Maturities, Weighted Average Maturity	[3]	6.66
Investment Securities, Continuous Unrealized Loss Position, Qualitative Disclosure [Abstract]
Investment Securities, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Securities		41		11
Investment Securities, Continuous Unrealized Loss Position, Fair Value [Abstract]
Investment Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value		$ 11,820		$ 1,082
Investment Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		855		1,715
Investment Securities, Continuous Unrealized Loss Position, Fair Value		12,675		2,797
Investment Securities, Continuous Unrealized Loss Position, Aggregate Losses [Abstract]
Investment Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Losses		322		41
Investment Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Losses		2		18
Investment Securities, Continuous Unrealized Loss Position, Accumulated Loss		324		59
Other than Temporary Impairment Losses, Investment Securities, Portion Recognized in Earnings, Net, Qualitative Disclosures, Lowest Current Credit Rating [Abstract]
Investment Securities, Portfolio Concentration Rated AAA to AA, Carrying Value		140,184
Investment Securities, Portfolio Concentration Rated AAA to AA, Fair Value		156,641
Investment Securities, Portfolio Concentration Rated A to BBB, Carrying Value		0
Investment Securities, Portfolio Concentration Rated A to BBB, Fair Value		0
Investment Securities, Portfolio Concentration Rated Below Investment Grade, Carrying Value		0
Investment Securities, Portfolio Concentration Rated Below Investment Grade, Fair Value		0
Investment Securities, Portfolio Concentration Not Rated, Carrying Value		64,820
Investment Securities, Portfolio Concentration Not Rated, Fair Value		66,154
U.S. government agency residential mortgage-backed securities [Member] | Other [Member]
Schedule of Investment (Held-to-Maturity) Securities [Line Items]
Investment Securities, Amortized Cost		20,777		26,721
Investment Securities, Debt Maturities, Carrying Value		20,777	[5]	26,833
Investment Securities, Fair Value		21,473	[5]	27,874
Investment Securities, Gross Unrealized Gain		767	[1]	1,063	[2]
Investment Securities, Gross Unrealized Loss		(71)	[1]	(22)	[2]
Investment Securities, Debt Maturities, Carrying Value [Abstract]
Held-to-maturity Securities, Debt Maturities, without Single Maturity Date, Carrying value		20,777
Investment Securities, Debt Maturities, Carrying Value		20,777	[5]	26,833
Investment Securities, Debt Maturities, Fair Value, Rolling Maturity [Abstract]
Investment Securities, Debt Maturities, without Single Maturity Date, Fair value		21,473
Investment Securities, Fair Value		$ 21,473	[5]	$ 27,874
Investment Securities, Debt Maturities, Nominal Yield [Abstract]
Investment Securities, Debt Maturities, Nominal Yield	[6]	2.76%
Investment Securities, Debt Maturities, Average Expected Life of Mortgage-backed Securities		4 years 8 months 12 days
Investment Securities, Continuous Unrealized Loss Position, Qualitative Disclosure [Abstract]
Investment Securities, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Securities		1		1
Investment Securities, Continuous Unrealized Loss Position, Fair Value [Abstract]
Investment Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value		$ 4,358		$ 5,533
Investment Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		0		0
Investment Securities, Continuous Unrealized Loss Position, Fair Value		4,358		5,533
Investment Securities, Continuous Unrealized Loss Position, Aggregate Losses [Abstract]
Investment Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Losses		71		22
Investment Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Losses		0		0
Investment Securities, Continuous Unrealized Loss Position, Accumulated Loss		71		$ 22
Other than Temporary Impairment Losses, Investment Securities, Portion Recognized in Earnings, Net, Qualitative Disclosures, Lowest Current Credit Rating [Abstract]
Investment Securities, Portfolio Concentration Rated AAA to AA, Carrying Value	[5]	0
Investment Securities, Portfolio Concentration Rated AAA to AA, Fair Value	[5]	0
Investment Securities, Portfolio Concentration Rated A to BBB, Carrying Value	[5]	0
Investment Securities, Portfolio Concentration Rated A to BBB, Fair Value	[5]	0
Investment Securities, Portfolio Concentration Rated Below Investment Grade, Carrying Value	[5]	0
Investment Securities, Portfolio Concentration Rated Below Investment Grade, Fair Value	[5]	0
Investment Securities, Portfolio Concentration Not Rated, Carrying Value	[5]	20,777
Investment Securities, Portfolio Concentration Not Rated, Fair Value	[5]	$ 21,473
[1]	Gross unrealized gains and losses are not recognized in AOCI in the Consolidated Balance Sheets.
[2]	Gross unrealized gains and losses are not recognized in AOCI in the Consolidated Balance Sheets.
[3]	Expected maturities may differ from contractual maturities because borrowers may have the right to call or prepay obligations with or without penalty.
[4]	Calculated on a taxable equivalent basis using a 39% effective tax rate.
[5]	U.S. government and government sponsored enterprises are not rated by the nationally-recognized rating agencies as these securities are guaranteed by agencies of the U.S. government or government-sponsored enterprises.
[6]	The nominal yield on residential mortgage-backed securities is based upon prepayment assumptions at the purchase date. Actual yields earned may differ significantly based upon actual prepayments. See Quarterly Financial Summary - Unaudited for current yields on the investment securities portfolio.

Available for Sale Securities (

Available for Sale Securities (Details)		12 Months Ended
		Dec. 31, 2016USD ($)		Dec. 31, 2015USD ($)		Dec. 31, 2014USD ($)
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost		$ 8,691,728,000		$ 9,004,624,000
Available-for-sale Securities, Fair Value		8,676,829,000		9,042,733,000
Available-for-sale Securities, Gross Unrealized Gain		60,165,000	[1]	79,970,000	[2]
Available-for-sale Securities, Gross Unrealized Loss		(74,846,000)	[1]	(41,034,000)	[2]
Available-for-Sale Securities, Other Than Temporary Impairments		$ (218,000)	[3]	(827,000)	[4]
Available-for-sale Securities, Debt Maturities, Nominal Yield [Abstract]
Available-for-sale Securities, Debt Maturities, Nominal Yield		1.84%
Available-for-sale Securities, Gross Realized Gain (Loss), Disclosures [Abstract]
Available-for-sale Securities, Proceeds		$ 899,381,000		1,600,380,000		$ 2,664,740,000
Available-for-sale Securities, Gross realized gains		11,696,000		15,849,000		24,923,000
Available-for-sale Securities, Gross realized losses		(21,000)		(3,791,000)		(23,384,000)
Available-for-sale Securites, Related federal and state income tax expense		4,542,000		4,691,000		599,000
Available-for-sale Securities, Pledged as Collateral [Abstract]
Available-for-sale Securities, Pledged As Collateral, Amortized cost		7,353,116,000		6,831,743,000
Available-for-sale Securities, Pledged As Collateral, Fair value		$ 7,327,470,000		$ 6,849,524,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Qualitative Disclosure [Abstract]
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Securities		488		419
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value [Abstract]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value		$ 5,231,605,000		$ 3,873,809,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		178,249,000		716,700,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value		5,409,854,000		4,590,509,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Losses [Abstract]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		70,818,000		28,496,000
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		4,246,000		13,365,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss		75,064,000		41,861,000
Other than Temporary Impairment Losses, Investments, Available-for-sale Securities, Portion Recognized In Earnings, Net Qualitative Disclosures, Lowest Current Credit Rating [Abstract]
Available-for-sale securities, Portfolio Concentration Rated AAA To AA, Amortized Cost		27,747,000
Available-for-sale Securities, Portfolio Concentration Rated AAA To AA, Fair Value		28,568,000
Available-for-sale Securities, Portfolio Concentration Rated A To BBB, Amortized Cost		10,391,000
Available-for-sale Securities, Portfolio Concentration Rated A To BBB, Fair Value		10,414,000
Available-for-sale Securities, Portfolio Concentration Rated Below Investment Grade, Amortized Cost		111,957,000
Available-for-sale Securities, Portfolio Concentration Rated Below Investment Grade, Fair Value		128,832,000
Available-for-sale Securities, Portfolio Concentration Not Rated, Amortized Cost		8,541,633,000
Available-for-sale Securities, Portfolio Concentration Not Rated, Fair Value		8,509,015,000
Fixed maturity securities [Member]
Available-for-sale Securities, Debt Maturities, Amortized Cost, Rolling Maturity [Abstract]
Available-for-sale Securities, Debt Maturities, Less than One Year, Amortized Cost		41,758,000
Available-for-sale Securities, Debt Maturities, One to Five Years, Amortized Cost		935,235,000
Available-for-sale Securities, Debt Maturities, Six to Ten Years, Amortized Cost		1,834,638,000
Available-for-sale Securities, Debt Maturities, Over Ten Years, Amortized Cost		270,569,000
Available-for-sale Securities, Debt Maturities, Single Maturity Date, Amortized Cost Basis		3,082,200,000
Available-for-sale Securities, Debt Maturities, Fair Value, Rolling Maturity [Abstract]
Available-for-sale Securities, Debt Maturities, Less Than One Year, Fair Value		41,759,000
Available-for-sale Securities, Debt Maturities, One to Five Years, Fair Value		933,506,000
Available-for-sale Securities, Debt Maturities, Six to Ten Years, Fair Value		1,822,778,000
Available-for-sale Securities, Debt Maturities, Over Ten Years, Fair Value		266,034,000
Available-for-sale Securities, Debt Maturities, Single Maturity Date, Fair value		$ 3,064,077,000
Available-for-sale Securities, Debt Maturities, Nominal Yield [Abstract]
Available-for-sale Securities, Debt Maturities, Less than One Year, Nominal Yield		1.89%
Available-for-sale Securities, Debt Maturities, One to Five Years, Nominal Yield		1.82%
Available-for-sale Securities, Debt Maturities, Six to Ten Years, Nominal Yield		1.85%
Available-for-sale Securities, Debt Maturities, Greater Than Ten Years, Nominal Yield		1.84%
Available-for-sale Securities, Debt Maturities, Nominal Yield		1.83%
Available-for-sale Securities, Debt Maturities, Weighted Average Maturity	[5]	6.95
U.S. Treasury securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost		$ 1,000,000		1,000,000
Available-for-sale Securities, Fair Value		999,000		995,000
Available-for-sale Securities, Gross Unrealized Gain		0	[1]	0	[2]
Available-for-sale Securities, Gross Unrealized Loss		(1,000)	[1]	(5,000)	[2]
Available-for-Sale Securities, Other Than Temporary Impairments		0	[3]	$ 0	[4]
Available-for-sale Securities, Debt Maturities, Amortized Cost, Rolling Maturity [Abstract]
Available-for-sale Securities, Debt Maturities, Less than One Year, Amortized Cost		0
Available-for-sale Securities, Debt Maturities, One to Five Years, Amortized Cost		1,000,000
Available-for-sale Securities, Debt Maturities, Six to Ten Years, Amortized Cost		0
Available-for-sale Securities, Debt Maturities, Over Ten Years, Amortized Cost		0
Available-for-sale Securities, Debt Maturities, Single Maturity Date, Amortized Cost Basis		1,000,000
Available-for-sale Securities, Debt Maturities, Fair Value, Rolling Maturity [Abstract]
Available-for-sale Securities, Debt Maturities, Less Than One Year, Fair Value		0
Available-for-sale Securities, Debt Maturities, One to Five Years, Fair Value		999,000
Available-for-sale Securities, Debt Maturities, Six to Ten Years, Fair Value		0
Available-for-sale Securities, Debt Maturities, Over Ten Years, Fair Value		0
Available-for-sale Securities, Debt Maturities, Single Maturity Date, Fair value		$ 999,000
Available-for-sale Securities, Debt Maturities, Nominal Yield [Abstract]
Available-for-sale Securities, Debt Maturities, Less than One Year, Nominal Yield		0.00%
Available-for-sale Securities, Debt Maturities, One to Five Years, Nominal Yield		0.87%
Available-for-sale Securities, Debt Maturities, Six to Ten Years, Nominal Yield		0.00%
Available-for-sale Securities, Debt Maturities, Greater Than Ten Years, Nominal Yield		0.00%
Available-for-sale Securities, Debt Maturities, Nominal Yield		0.87%
Available-for-sale Securities, Debt Maturities, Weighted Average Maturity	[5]	1.04
Available-for-sale Securities, Continuous Unrealized Loss Position, Qualitative Disclosure [Abstract]
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Securities		1		1
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value [Abstract]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value		$ 999,000		$ 995,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		0		0
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value		999,000		995,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Losses [Abstract]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		1,000		5,000
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		0		0
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss		1,000		5,000
Other than Temporary Impairment Losses, Investments, Available-for-sale Securities, Portion Recognized In Earnings, Net Qualitative Disclosures, Lowest Current Credit Rating [Abstract]
Available-for-sale securities, Portfolio Concentration Rated AAA To AA, Amortized Cost		0
Available-for-sale Securities, Portfolio Concentration Rated AAA To AA, Fair Value		0
Available-for-sale Securities, Portfolio Concentration Rated A To BBB, Amortized Cost		0
Available-for-sale Securities, Portfolio Concentration Rated A To BBB, Fair Value		0
Available-for-sale Securities, Portfolio Concentration Rated Below Investment Grade, Amortized Cost		0
Available-for-sale Securities, Portfolio Concentration Rated Below Investment Grade, Fair Value		0
Available-for-sale Securities, Portfolio Concentration Not Rated, Amortized Cost		1,000,000
Available-for-sale Securities, Portfolio Concentration Not Rated, Fair Value		999,000
Municipal and other tax-exempt securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost		41,050,000		56,681,000
Available-for-sale Securities, Fair Value		40,993,000		56,817,000
Available-for-sale Securities, Gross Unrealized Gain		343,000	[1]	873,000	[2]
Available-for-sale Securities, Gross Unrealized Loss		(400,000)	[1]	(737,000)	[2]
Available-for-Sale Securities, Other Than Temporary Impairments		0	[3]	$ 0	[4]
Available-for-sale Securities, Debt Maturities, Amortized Cost, Rolling Maturity [Abstract]
Available-for-sale Securities, Debt Maturities, Less than One Year, Amortized Cost		9,848,000
Available-for-sale Securities, Debt Maturities, One to Five Years, Amortized Cost		12,254,000
Available-for-sale Securities, Debt Maturities, Six to Ten Years, Amortized Cost		2,103,000
Available-for-sale Securities, Debt Maturities, Over Ten Years, Amortized Cost		16,845,000
Available-for-sale Securities, Debt Maturities, Single Maturity Date, Amortized Cost Basis		41,050,000
Available-for-sale Securities, Debt Maturities, Fair Value, Rolling Maturity [Abstract]
Available-for-sale Securities, Debt Maturities, Less Than One Year, Fair Value		9,903,000
Available-for-sale Securities, Debt Maturities, One to Five Years, Fair Value		12,399,000
Available-for-sale Securities, Debt Maturities, Six to Ten Years, Fair Value		2,151,000
Available-for-sale Securities, Debt Maturities, Over Ten Years, Fair Value		16,540,000
Available-for-sale Securities, Debt Maturities, Single Maturity Date, Fair value		$ 40,993,000
Available-for-sale Securities, Debt Maturities, Nominal Yield [Abstract]
Available-for-sale Securities, Debt Maturities, Less than One Year, Nominal Yield	[6]	4.81%
Available-for-sale Securities, Debt Maturities, One to Five Years, Nominal Yield	[6]	4.01%
Available-for-sale Securities, Debt Maturities, Six to Ten Years, Nominal Yield	[6]	3.47%
Available-for-sale Securities, Debt Maturities, Greater Than Ten Years, Nominal Yield	[6],[7]	2.28%
Available-for-sale Securities, Debt Maturities, Nominal Yield	[6]	3.46%
Available-for-sale Securities, Debt Maturities, Weighted Average Maturity	[5]	7.95
Available-for-sale Securities, Debt Maturities, Effective tax rate for nominal yield calculation		39.00%
Available-for-sale Securities, Debt Maturities, Number of days for interest rates to reset		35 days
Available-for-sale Securities, Continuous Unrealized Loss Position, Qualitative Disclosure [Abstract]
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Securities		24		20
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value [Abstract]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value		$ 15,666,000		$ 9,909,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		4,689,000		11,664,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value		20,355,000		21,573,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Losses [Abstract]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		22,000		27,000
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		378,000		710,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss		400,000		737,000
Other than Temporary Impairment Losses, Investments, Available-for-sale Securities, Portion Recognized In Earnings, Net Qualitative Disclosures, Lowest Current Credit Rating [Abstract]
Available-for-sale securities, Portfolio Concentration Rated AAA To AA, Amortized Cost		23,343,000
Available-for-sale Securities, Portfolio Concentration Rated AAA To AA, Fair Value		23,657,000
Available-for-sale Securities, Portfolio Concentration Rated A To BBB, Amortized Cost		5,595,000
Available-for-sale Securities, Portfolio Concentration Rated A To BBB, Fair Value		5,237,000
Available-for-sale Securities, Portfolio Concentration Rated Below Investment Grade, Amortized Cost		0
Available-for-sale Securities, Portfolio Concentration Rated Below Investment Grade, Fair Value		0
Available-for-sale Securities, Portfolio Concentration Not Rated, Amortized Cost		12,112,000
Available-for-sale Securities, Portfolio Concentration Not Rated, Fair Value		12,099,000
Commercial mortgage-backed securities guaranteed by U.S. government agencies [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost		3,035,750,000		2,919,044,000
Available-for-sale Securities, Fair Value		3,017,933,000		2,905,796,000
Available-for-sale Securities, Gross Unrealized Gain		5,472,000	[1]	5,396,000	[2]
Available-for-sale Securities, Gross Unrealized Loss		(23,289,000)	[1]	(18,644,000)	[2]
Available-for-Sale Securities, Other Than Temporary Impairments		0	[3]	$ 0	[4]
Available-for-sale Securities, Debt Maturities, Amortized Cost, Rolling Maturity [Abstract]
Available-for-sale Securities, Debt Maturities, Less than One Year, Amortized Cost		31,910,000
Available-for-sale Securities, Debt Maturities, One to Five Years, Amortized Cost		921,981,000
Available-for-sale Securities, Debt Maturities, Six to Ten Years, Amortized Cost		1,832,535,000
Available-for-sale Securities, Debt Maturities, Over Ten Years, Amortized Cost		249,324,000
Available-for-sale Securities, Debt Maturities, Single Maturity Date, Amortized Cost Basis		3,035,750,000
Available-for-sale Securities, Debt Maturities, Fair Value, Rolling Maturity [Abstract]
Available-for-sale Securities, Debt Maturities, Less Than One Year, Fair Value		31,856,000
Available-for-sale Securities, Debt Maturities, One to Five Years, Fair Value		920,108,000
Available-for-sale Securities, Debt Maturities, Six to Ten Years, Fair Value		1,820,627,000
Available-for-sale Securities, Debt Maturities, Over Ten Years, Fair Value		245,342,000
Available-for-sale Securities, Debt Maturities, Single Maturity Date, Fair value		$ 3,017,933,000
Available-for-sale Securities, Debt Maturities, Nominal Yield [Abstract]
Available-for-sale Securities, Debt Maturities, Less than One Year, Nominal Yield		1.00%
Available-for-sale Securities, Debt Maturities, One to Five Years, Nominal Yield		1.79%
Available-for-sale Securities, Debt Maturities, Six to Ten Years, Nominal Yield		1.85%
Available-for-sale Securities, Debt Maturities, Greater Than Ten Years, Nominal Yield		1.82%
Available-for-sale Securities, Debt Maturities, Nominal Yield		1.81%
Available-for-sale Securities, Debt Maturities, Weighted Average Maturity	[5]	6.90
Available-for-sale Securities, Continuous Unrealized Loss Position, Qualitative Disclosure [Abstract]
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Securities		171		213
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value [Abstract]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value		$ 1,904,584,000		$ 1,582,469,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		38,875,000		484,258,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value		1,943,459,000		2,066,727,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Losses [Abstract]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		22,987,000		11,419,000
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		302,000		7,225,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss		23,289,000		18,644,000
Other than Temporary Impairment Losses, Investments, Available-for-sale Securities, Portion Recognized In Earnings, Net Qualitative Disclosures, Lowest Current Credit Rating [Abstract]
Available-for-sale securities, Portfolio Concentration Rated AAA To AA, Amortized Cost		0
Available-for-sale Securities, Portfolio Concentration Rated AAA To AA, Fair Value		0
Available-for-sale Securities, Portfolio Concentration Rated A To BBB, Amortized Cost		0
Available-for-sale Securities, Portfolio Concentration Rated A To BBB, Fair Value		0
Available-for-sale Securities, Portfolio Concentration Rated Below Investment Grade, Amortized Cost		0
Available-for-sale Securities, Portfolio Concentration Rated Below Investment Grade, Fair Value		0
Available-for-sale Securities, Portfolio Concentration Not Rated, Amortized Cost		3,035,750,000
Available-for-sale Securities, Portfolio Concentration Not Rated, Fair Value		3,017,933,000
Other debt securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost		4,400,000		4,400,000
Available-for-sale Securities, Fair Value		4,152,000		4,151,000
Available-for-sale Securities, Gross Unrealized Gain		0	[1]	0	[2]
Available-for-sale Securities, Gross Unrealized Loss		(248,000)	[1]	(249,000)	[2]
Available-for-Sale Securities, Other Than Temporary Impairments		0	[3]	$ 0	[4]
Available-for-sale Securities, Debt Maturities, Amortized Cost, Rolling Maturity [Abstract]
Available-for-sale Securities, Debt Maturities, Less than One Year, Amortized Cost		0
Available-for-sale Securities, Debt Maturities, One to Five Years, Amortized Cost		0
Available-for-sale Securities, Debt Maturities, Six to Ten Years, Amortized Cost		0
Available-for-sale Securities, Debt Maturities, Over Ten Years, Amortized Cost		4,400,000
Available-for-sale Securities, Debt Maturities, Single Maturity Date, Amortized Cost Basis		4,400,000
Available-for-sale Securities, Debt Maturities, Fair Value, Rolling Maturity [Abstract]
Available-for-sale Securities, Debt Maturities, Less Than One Year, Fair Value		0
Available-for-sale Securities, Debt Maturities, One to Five Years, Fair Value		0
Available-for-sale Securities, Debt Maturities, Six to Ten Years, Fair Value		0
Available-for-sale Securities, Debt Maturities, Over Ten Years, Fair Value		4,152,000
Available-for-sale Securities, Debt Maturities, Single Maturity Date, Fair value		$ 4,152,000
Available-for-sale Securities, Debt Maturities, Nominal Yield [Abstract]
Available-for-sale Securities, Debt Maturities, Less than One Year, Nominal Yield		0.00%
Available-for-sale Securities, Debt Maturities, One to Five Years, Nominal Yield		0.00%
Available-for-sale Securities, Debt Maturities, Six to Ten Years, Nominal Yield		0.00%
Available-for-sale Securities, Debt Maturities, Greater Than Ten Years, Nominal Yield		1.71%
Available-for-sale Securities, Debt Maturities, Nominal Yield		1.71%
Available-for-sale Securities, Debt Maturities, Weighted Average Maturity	[5]	30.66
Available-for-sale Securities, Continuous Unrealized Loss Position, Qualitative Disclosure [Abstract]
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Securities		2		2
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value [Abstract]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value		$ 0		$ 0
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		4,152,000		4,151,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value		4,152,000		4,151,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Losses [Abstract]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		0		0
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		248,000		249,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss		248,000		249,000
Other than Temporary Impairment Losses, Investments, Available-for-sale Securities, Portion Recognized In Earnings, Net Qualitative Disclosures, Lowest Current Credit Rating [Abstract]
Available-for-sale securities, Portfolio Concentration Rated AAA To AA, Amortized Cost		4,400,000
Available-for-sale Securities, Portfolio Concentration Rated AAA To AA, Fair Value		4,152,000
Available-for-sale Securities, Portfolio Concentration Rated A To BBB, Amortized Cost		0
Available-for-sale Securities, Portfolio Concentration Rated A To BBB, Fair Value		0
Available-for-sale Securities, Portfolio Concentration Rated Below Investment Grade, Amortized Cost		0
Available-for-sale Securities, Portfolio Concentration Rated Below Investment Grade, Fair Value		0
Available-for-sale Securities, Portfolio Concentration Not Rated, Amortized Cost		0
Available-for-sale Securities, Portfolio Concentration Not Rated, Fair Value		0
Residential mortgage-backed securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost		5,576,543,000		5,989,207,000
Available-for-sale Securities, Fair Value		5,575,921,000		6,037,469,000
Available-for-sale Securities, Gross Unrealized Gain		50,377,000	[1]	70,448,000	[2]
Available-for-sale Securities, Gross Unrealized Loss		(50,781,000)	[1]	(21,359,000)	[2]
Available-for-Sale Securities, Other Than Temporary Impairments		(218,000)	[3]	$ (827,000)	[4]
Available-for-sale Securities, Debt Maturities, Amortized Cost, Rolling Maturity [Abstract]
Available-for-sale Securities, Debt Maturities, without Single Maturity Date, Amortized Cost Basis		5,576,543,000
Available-for-sale Securities, Debt Maturities, Fair Value, Rolling Maturity [Abstract]
Available-for-sale Securities, Debt Maturities, without Single Maturity Date, Fair value		$ 5,575,921,000
Available-for-sale Securities, Debt Maturities, Nominal Yield [Abstract]
Available-for-sale Securities, Debt Maturities, Nominal Yield		1.86%
Available-for-sale Securities, Debt Maturities, Average Expected Life of Mortgage-backed Securities		3 years 10 months 8 days
Available-for-sale Securities, Continuous Unrealized Loss Position, Qualitative Disclosure [Abstract]
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Securities		186		122
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value [Abstract]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value		$ 3,308,229,000		$ 2,279,654,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		129,716,000		215,636,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value		3,437,945,000		2,495,290,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Losses [Abstract]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		47,767,000		17,040,000
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		3,232,000		5,146,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss		50,999,000		22,186,000
U.S. government agency residential mortgage-backed securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost		5,475,351,000	[8]	5,861,096,000
Available-for-sale Securities, Fair Value		5,460,386,000	[8]	5,898,351,000
Available-for-sale Securities, Gross Unrealized Gain		35,800,000	[1]	58,614,000	[2]
Available-for-sale Securities, Gross Unrealized Loss		(50,765,000)	[1]	(21,359,000)	[2]
Available-for-Sale Securities, Other Than Temporary Impairments		$ 0	[3]	$ 0	[4]
Available-for-sale Securities, Continuous Unrealized Loss Position, Qualitative Disclosure [Abstract]
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Securities		180		110
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value [Abstract]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value		$ 3,300,298,000		$ 2,279,654,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		116,208,000		197,890,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value		3,416,506,000		2,477,544,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Losses [Abstract]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		47,593,000		17,040,000
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		3,172,000		4,319,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss		50,765,000		21,359,000
Other than Temporary Impairment Losses, Investments, Available-for-sale Securities, Portion Recognized In Earnings, Net Qualitative Disclosures, Lowest Current Credit Rating [Abstract]
Available-for-sale securities, Portfolio Concentration Rated AAA To AA, Amortized Cost	[8]	0
Available-for-sale Securities, Portfolio Concentration Rated AAA To AA, Fair Value	[8]	0
Available-for-sale Securities, Portfolio Concentration Rated A To BBB, Amortized Cost	[8]	0
Available-for-sale Securities, Portfolio Concentration Rated A To BBB, Fair Value	[8]	0
Available-for-sale Securities, Portfolio Concentration Rated Below Investment Grade, Amortized Cost	[8]	0
Available-for-sale Securities, Portfolio Concentration Rated Below Investment Grade, Fair Value	[8]	0
Available-for-sale Securities, Portfolio Concentration Not Rated, Amortized Cost	[8]	5,475,351,000
Available-for-sale Securities, Portfolio Concentration Not Rated, Fair Value	[8]	5,460,386,000
U.S. government agency residential mortgage-backed securities [Member] | FNMA [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost		3,062,525,000		3,156,214,000
Available-for-sale Securities, Fair Value		3,055,676,000		3,187,215,000
Available-for-sale Securities, Gross Unrealized Gain		25,066,000	[1]	41,502,000	[2]
Available-for-sale Securities, Gross Unrealized Loss		(31,915,000)	[1]	(10,501,000)	[2]
Available-for-Sale Securities, Other Than Temporary Impairments		$ 0	[3]	$ 0	[4]
Available-for-sale Securities, Continuous Unrealized Loss Position, Qualitative Disclosure [Abstract]
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Securities		91		55
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value [Abstract]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value		$ 1,787,644,000		$ 1,188,022,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		72,105,000		18,236,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value		1,859,749,000		1,206,258,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Losses [Abstract]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		30,238,000		10,262,000
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		1,677,000		239,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss		31,915,000		10,501,000
U.S. government agency residential mortgage-backed securities [Member] | FHLMC [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost		1,534,451,000		1,940,915,000
Available-for-sale Securities, Fair Value		1,531,116,000		1,949,335,000
Available-for-sale Securities, Gross Unrealized Gain		8,475,000	[1]	14,727,000	[2]
Available-for-sale Securities, Gross Unrealized Loss		(11,810,000)	[1]	(6,307,000)	[2]
Available-for-Sale Securities, Other Than Temporary Impairments		$ 0	[3]	$ 0	[4]
Available-for-sale Securities, Continuous Unrealized Loss Position, Qualitative Disclosure [Abstract]
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Securities		58		40
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value [Abstract]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value		$ 964,017,000		$ 726,713,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		18,307,000		77,545,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value		982,324,000		804,258,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Losses [Abstract]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		11,210,000		4,827,000
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		600,000		1,480,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss		11,810,000		6,307,000
U.S. government agency residential mortgage-backed securities [Member] | GNMA [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost		878,375,000		763,967,000
Available-for-sale Securities, Fair Value		873,594,000		761,801,000
Available-for-sale Securities, Gross Unrealized Gain		2,259,000	[1]	2,385,000	[2]
Available-for-sale Securities, Gross Unrealized Loss		(7,040,000)	[1]	(4,551,000)	[2]
Available-for-Sale Securities, Other Than Temporary Impairments		$ 0	[3]	$ 0	[4]
Available-for-sale Securities, Continuous Unrealized Loss Position, Qualitative Disclosure [Abstract]
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Securities		31		15
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value [Abstract]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value		$ 548,637,000		$ 364,919,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		25,796,000		102,109,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value		574,433,000		467,028,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Losses [Abstract]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		6,145,000		1,951,000
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		895,000		2,600,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss		7,040,000		4,551,000
Privately issued residential mortgage-backed securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost		101,192,000		128,111,000
Available-for-sale Securities, Fair Value		115,535,000		139,118,000
Available-for-sale Securities, Gross Unrealized Gain		14,577,000	[1]	11,834,000	[2]
Available-for-sale Securities, Gross Unrealized Loss		(16,000)	[1]	0	[2]
Available-for-Sale Securities, Other Than Temporary Impairments		$ (218,000)	[3]	$ (827,000)	[4]
Available-for-sale Securities, Continuous Unrealized Loss Position, Qualitative Disclosure [Abstract]
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Securities		6	[9]	12	[10]
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value [Abstract]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value		$ 7,931,000	[9]	$ 0	[10]
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		13,508,000	[9]	17,746,000	[10]
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value		21,439,000	[9]	17,746,000	[10]
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Losses [Abstract]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		174,000	[9]	0	[10]
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		60,000	[9]	827,000	[10]
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss		234,000	[9]	$ 827,000	[10]
Other than Temporary Impairment Losses, Investments, Available-for-sale Securities, Portion Recognized In Earnings, Net Qualitative Disclosures, Lowest Current Credit Rating [Abstract]
Available-for-sale securities, Portfolio Concentration Rated AAA To AA, Amortized Cost		0
Available-for-sale Securities, Portfolio Concentration Rated AAA To AA, Fair Value		0
Available-for-sale Securities, Portfolio Concentration Rated A To BBB, Amortized Cost		0
Available-for-sale Securities, Portfolio Concentration Rated A To BBB, Fair Value		0
Available-for-sale Securities, Portfolio Concentration Rated Below Investment Grade, Amortized Cost		101,192,000
Available-for-sale Securities, Portfolio Concentration Rated Below Investment Grade, Fair Value		115,535,000
Available-for-sale Securities, Portfolio Concentration Not Rated, Amortized Cost		0
Available-for-sale Securities, Portfolio Concentration Not Rated, Fair Value		$ 0
Other Than Temporary Impairment Losses, Investments, Available-for-sale Securities, Portion Recognized in Earnings, Net, Qualitative Disclosures, Assumptions Used to Develop Projected Cash Flows [Abstract]
Unemployment rate		Decreasing to 4.6% over the next 12 months and remain at 4.6% thereafter.		Decreasing to 4.8% over the next 12 months and remain at 4.8% thereafter.
Housing price appreciation/depreciation	[11]	Starting with current depreciated housing prices based on information derived from the FHFA1, appreciating 3.1% over the next 12 months, then flat for the following 12 months and then appreciating at 2% per year thereafter.		Starting with current depreciated housing prices based on information derived from the FHFA1, appreciating 3.5% over the next 12 months, then flat for the following 12 months and then appreciating at 2% per year thereafter.
Estimated liquidation costs		Reflect actual historical liquidations costs observed on Jumbo and Alt-A residential mortgage loans in securities owned by the Company.		Reflect actual historical liquidations costs observed on Jumbo and Alt-A residential mortgage loans in securities owned by the Company.
Discount rates		Estimated cash flows were discounted at rates that range from 2.00% to 6.25% based on our current expected yields.		Estimated cash flows were discounted at rates that range from 2.00% to 6.25% based on our current expected yields.
Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net [Abstract]
Available-for-sale Securities, Other than Temporary Impairment Losses		$ 0		$ (157,000)		0
Privately issued residential mortgage-backed securities [Member] | Alt A [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost		44,245,000		56,387,000
Available-for-sale Securities, Fair Value		51,512,000		62,574,000
Available-for-sale Securities, Gross Unrealized Gain		7,485,000	[1]	6,574,000	[2]
Available-for-sale Securities, Gross Unrealized Loss		0	[1]	0	[2]
Available-for-Sale Securities, Other Than Temporary Impairments		$ (218,000)	[3]	$ (387,000)	[4]
Available-for-sale Securities, Continuous Unrealized Loss Position, Qualitative Disclosure [Abstract]
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Securities		5	[9]	4	[10]
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value [Abstract]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value		$ 7,931,000	[9]	$ 0	[10]
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		7,410,000	[9]	9,264,000	[10]
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value		15,341,000	[9]	9,264,000	[10]
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Losses [Abstract]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		174,000	[9]	0	[10]
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		44,000	[9]	387,000	[10]
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss		218,000	[9]	387,000	[10]
Privately issued residential mortgage-backed securities [Member] | Jumbo A Loans [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost		56,947,000		71,724,000
Available-for-sale Securities, Fair Value		64,023,000		76,544,000
Available-for-sale Securities, Gross Unrealized Gain		7,092,000	[1]	5,260,000	[2]
Available-for-sale Securities, Gross Unrealized Loss		(16,000)	[1]	0	[2]
Available-for-Sale Securities, Other Than Temporary Impairments		$ 0	[3]	$ (440,000)	[4]
Available-for-sale Securities, Continuous Unrealized Loss Position, Qualitative Disclosure [Abstract]
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Securities		1	[9]	8	[10]
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value [Abstract]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value		$ 0	[9]	$ 0	[10]
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		6,098,000	[9]	8,482,000	[10]
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value		6,098,000	[9]	8,482,000	[10]
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Losses [Abstract]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		0	[9]	0	[10]
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		16,000	[9]	440,000	[10]
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss		16,000	[9]	440,000	[10]
Perpetual Preferred, Equity Securities and Mutual Funds [Member]
Available-for-sale Securities, Debt Maturities, Amortized Cost, Rolling Maturity [Abstract]
Available-for-sale Securities, Debt Maturities, without Single Maturity Date, Amortized Cost Basis		32,985,000
Available-for-sale Securities, Debt Maturities, Fair Value, Rolling Maturity [Abstract]
Available-for-sale Securities, Debt Maturities, without Single Maturity Date, Fair value		$ 36,831,000
Available-for-sale Securities, Debt Maturities, Nominal Yield [Abstract]
Available-for-sale Securities, Debt Maturities, Nominal Yield		0.00%
Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net [Abstract]
Available-for-sale Securities, Other than Temporary Impairment Losses		$ 0		(1,700,000)		$ (373,000)
Perpetual preferred stock [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost		15,561,000		17,171,000
Available-for-sale Securities, Fair Value		18,474,000		19,672,000
Available-for-sale Securities, Gross Unrealized Gain		2,913,000	[1]	2,501,000	[2]
Available-for-sale Securities, Gross Unrealized Loss		0	[1]	0	[2]
Available-for-Sale Securities, Other Than Temporary Impairments		$ 0	[3]	$ 0	[4]
Available-for-sale Securities, Continuous Unrealized Loss Position, Qualitative Disclosure [Abstract]
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Securities		0		0
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value [Abstract]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value		$ 0		$ 0
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		0		0
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value		0		0
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Losses [Abstract]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		0		0
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		0		0
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss		0		0
Other than Temporary Impairment Losses, Investments, Available-for-sale Securities, Portion Recognized In Earnings, Net Qualitative Disclosures, Lowest Current Credit Rating [Abstract]
Available-for-sale securities, Portfolio Concentration Rated AAA To AA, Amortized Cost		0
Available-for-sale Securities, Portfolio Concentration Rated AAA To AA, Fair Value		0
Available-for-sale Securities, Portfolio Concentration Rated A To BBB, Amortized Cost		4,796,000
Available-for-sale Securities, Portfolio Concentration Rated A To BBB, Fair Value		5,177,000
Available-for-sale Securities, Portfolio Concentration Rated Below Investment Grade, Amortized Cost		10,765,000
Available-for-sale Securities, Portfolio Concentration Rated Below Investment Grade, Fair Value		13,297,000
Available-for-sale Securities, Portfolio Concentration Not Rated, Amortized Cost		0
Available-for-sale Securities, Portfolio Concentration Not Rated, Fair Value		0
Equity securities and mutual funds [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost		17,424,000		17,121,000
Available-for-sale Securities, Fair Value		18,357,000		17,833,000
Available-for-sale Securities, Gross Unrealized Gain		1,060,000	[1]	752,000	[2]
Available-for-sale Securities, Gross Unrealized Loss		(127,000)	[1]	(40,000)	[2]
Available-for-Sale Securities, Other Than Temporary Impairments		$ 0	[3]	$ 0	[4]
Available-for-sale Securities, Continuous Unrealized Loss Position, Qualitative Disclosure [Abstract]
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Securities		104		61
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value [Abstract]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value		$ 2,127,000		$ 782,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		817,000		991,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value		2,944,000		1,773,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Losses [Abstract]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		41,000		5,000
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		86,000		35,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss		127,000		$ 40,000
Other than Temporary Impairment Losses, Investments, Available-for-sale Securities, Portion Recognized In Earnings, Net Qualitative Disclosures, Lowest Current Credit Rating [Abstract]
Available-for-sale securities, Portfolio Concentration Rated AAA To AA, Amortized Cost		4,000
Available-for-sale Securities, Portfolio Concentration Rated AAA To AA, Fair Value		759,000
Available-for-sale Securities, Portfolio Concentration Rated A To BBB, Amortized Cost		0
Available-for-sale Securities, Portfolio Concentration Rated A To BBB, Fair Value		0
Available-for-sale Securities, Portfolio Concentration Rated Below Investment Grade, Amortized Cost		0
Available-for-sale Securities, Portfolio Concentration Rated Below Investment Grade, Fair Value		0
Available-for-sale Securities, Portfolio Concentration Not Rated, Amortized Cost		17,420,000
Available-for-sale Securities, Portfolio Concentration Not Rated, Fair Value		$ 17,598,000
[1]	Gross unrealized gain/loss recognized in AOCI in the consolidated balance sheet.
[2]	Gross unrealized gain/loss recognized in AOCI in the consolidated balance sheet.
[3]	Amounts represent unrealized loss that remains in AOCI after an other-than-temporary credit loss has been recognized in income.
[4]	Amounts represent unrealized loss that remains in AOCI after an other-than-temporary credit loss has been recognized in income.
[5]	Expected maturities may differ from contractual maturities, because borrowers may have the right to call or prepay obligations with or without penalty.
[6]	Calculated on a taxable equivalent basis using a 39% effective tax rate.
[7]	Nominal yield on municipal and other tax-exempt securities and other debt securities with contractual maturity dates over ten years are based on variable rates which generally are reset within 35 days.
[8]	U.S. government and government sponsored enterprises are not rated by the nationally-recognized rating agencies as these securities are guaranteed by agencies of the U.S. government or government-sponsored enterprises.
[9]	Includes securities for which an unrealized loss remains in AOCI after an other-than-temporary credit loss has been recognized in income.
[10]	Includes securities for which an unrealized loss remains in AOCI after an other-than-temporary credit loss has been recognized in income.
[11]	Federal Housing Finance Agency

Rollforward of Credit-Related O

Rollforward of Credit-Related Other-than-temporary Impairment Recognized in Earnings (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Roll Forward]
Balance of credit related OTTI recognized on available for sale debt securities, beginning of period	$ 54,504	$ 54,347	$ 67,346
Additions for credit-related OTTI not previously recognized	0	0	0
Additions for increases in credit-related OTTI previously recognized when there is no intent to sell and no requirement to sell before recovery of amortized cost	0	157	0
Reductions for change in intent to hold before recovery	0	0	0
Sales	0	0	(12,999)
Balance of credit related OTTI recognized on available for sale debt securities, end of period	$ 54,504	$ 54,504	$ 54,347

Securities Fair Value Option Se

Securities Fair Value Option Securities (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Schedule of Fair Value Option Securities [Line Items]
Fair Value Option Securities, Fair Value	$ 77,046	$ 444,217
U.S. government agency residential mortgage-backed securities [Member]
Schedule of Fair Value Option Securities [Line Items]
Fair Value Option Securities, Fair Value	77,046	444,217
Fair Value Option Securities, Net Unrealized Gain (Loss)	$ (1,777)	$ (2,060)

Securities Restricted Equity Se

Securities Restricted Equity Securities (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Restricted Equity Securities [Abstract]
Federal Reserve Bank Stock	$ 36,498	$ 36,148
Federal Home Loan Bank Stock	270,541	237,365
Other	201	171
Total	$ 307,240	$ 273,684

Derivatives, Fair Value of Deri

Derivatives, Fair Value of Derivatives Contracts (Details) - USD ($) $ in Thousands	Dec. 31, 2016		Dec. 31, 2015
Derivative Assets, Fair Value, Net [Abstract]
Derivative contracts, net of cash margin, Assets, Fair Value	$ 689,872		$ 586,270
Derivative Liabilities, Fair Value, Net [Abstract]
Derivative contracts, net of cash margin, Liabilities, Fair Value	664,531		581,701
Not Designated as Hedging Instrument [Member]
Notional Amount of Derivatives [Abstract]
Derivative Assets, Notional	22,437,314	[1]	17,153,221	[2]
Derivative Liabilities, Notional	22,178,359	[1]	16,785,014	[2]
Derivative Assets, Fair Value, Net [Abstract]
Derivative Assets, Gross Fair Value	789,791		663,343
Derivative Assets, Netting Adjustments	(89,368)		(52,433)
Derivative Assets, Net Fair Value Before Cash Collateral	700,423		610,910
Derivative Assets, Fair Value, Cash Collateral	(10,551)		(24,640)
Derivative contracts, net of cash margin, Assets, Fair Value	689,872		586,270
Derivative Liabilities, Fair Value, Net [Abstract]
Derivative Liabilities, Fair Value, Gross Liability	801,809		659,171
Derivative Liabilities, Netting Adjustments	(89,368)		(52,433)
Derivative Liabilities, Net Fair Value Before Cash Collateral	712,441		606,738
Derivative Liabilities, Fair Value, Cash Collateral	(47,910)		(25,037)
Derivative contracts, net of cash margin, Liabilities, Fair Value	664,531		581,701
Not Designated as Hedging Instrument [Member] | To-be-announced residential mortgage-backed securities [Member]
Notional Amount of Derivatives [Abstract]
Derivative Assets, Notional	16,949,152	[1]	14,583,052	[2]
Derivative Liabilities, Notional	16,637,532	[1]	14,168,927	[2]
Derivative Assets, Fair Value, Net [Abstract]
Derivative Assets, Gross Fair Value	180,695		43,270
Derivative Assets, Netting Adjustments	(60,555)		(28,305)
Derivative Assets, Net Fair Value Before Cash Collateral	120,140		14,965
Derivative Assets, Fair Value, Cash Collateral	0		0
Derivative contracts, net of cash margin, Assets, Fair Value	120,140		14,965
Derivative Liabilities, Fair Value, Net [Abstract]
Derivative Liabilities, Fair Value, Gross Liability	176,928		40,141
Derivative Liabilities, Netting Adjustments	(60,555)		(28,305)
Derivative Liabilities, Net Fair Value Before Cash Collateral	116,373		11,836
Derivative Liabilities, Fair Value, Cash Collateral	0		(1,308)
Derivative contracts, net of cash margin, Liabilities, Fair Value	116,373		10,528
Not Designated as Hedging Instrument [Member] | Interest rate swaps [Member]
Notional Amount of Derivatives [Abstract]
Derivative Assets, Notional	1,403,408	[1]	1,332,044	[2]
Derivative Liabilities, Notional	1,403,408	[1]	1,332,044	[2]
Derivative Assets, Fair Value, Net [Abstract]
Derivative Assets, Gross Fair Value	34,442		31,744
Derivative Assets, Netting Adjustments	0		0
Derivative Assets, Net Fair Value Before Cash Collateral	34,442		31,744
Derivative Assets, Fair Value, Cash Collateral	(4,567)		(1,424)
Derivative contracts, net of cash margin, Assets, Fair Value	29,875		30,320
Derivative Liabilities, Fair Value, Net [Abstract]
Derivative Liabilities, Fair Value, Gross Liability	34,442		31,928
Derivative Liabilities, Netting Adjustments	0		0
Derivative Liabilities, Net Fair Value Before Cash Collateral	34,442		31,928
Derivative Liabilities, Fair Value, Cash Collateral	(11,977)		(20,530)
Derivative contracts, net of cash margin, Liabilities, Fair Value	22,465		11,398
Not Designated as Hedging Instrument [Member] | Energy contracts [Member]
Notional Amount of Derivatives [Abstract]
Derivative Assets, Notional	835,566	[1]	470,613	[2]
Derivative Liabilities, Notional	820,365	[1]	463,703	[2]
Derivative Assets, Fair Value, Net [Abstract]
Derivative Assets, Gross Fair Value	64,140		83,045
Derivative Assets, Netting Adjustments	(28,298)		(22,970)
Derivative Assets, Net Fair Value Before Cash Collateral	35,842		60,075
Derivative Assets, Fair Value, Cash Collateral	(71)		(18,606)
Derivative contracts, net of cash margin, Assets, Fair Value	35,771		41,469
Derivative Liabilities, Fair Value, Net [Abstract]
Derivative Liabilities, Fair Value, Gross Liability	64,306		81,869
Derivative Liabilities, Netting Adjustments	(28,298)		(22,970)
Derivative Liabilities, Net Fair Value Before Cash Collateral	36,008		58,899
Derivative Liabilities, Fair Value, Cash Collateral	(31,534)		0
Derivative contracts, net of cash margin, Liabilities, Fair Value	4,474		58,899
Not Designated as Hedging Instrument [Member] | Agricultural contracts [Member]
Notional Amount of Derivatives [Abstract]
Derivative Assets, Notional	53,209	[1]	61,662	[2]
Derivative Liabilities, Notional	53,216	[1]	61,657	[2]
Derivative Assets, Fair Value, Net [Abstract]
Derivative Assets, Gross Fair Value	1,382		2,591
Derivative Assets, Netting Adjustments	(515)		(1,158)
Derivative Assets, Net Fair Value Before Cash Collateral	867		1,433
Derivative Assets, Fair Value, Cash Collateral	0		0
Derivative contracts, net of cash margin, Assets, Fair Value	867		1,433
Derivative Liabilities, Fair Value, Net [Abstract]
Derivative Liabilities, Fair Value, Gross Liability	1,365		2,579
Derivative Liabilities, Netting Adjustments	(515)		(1,158)
Derivative Liabilities, Net Fair Value Before Cash Collateral	850		1,421
Derivative Liabilities, Fair Value, Cash Collateral	(769)		(1,248)
Derivative contracts, net of cash margin, Liabilities, Fair Value	81		173
Not Designated as Hedging Instrument [Member] | Foreign exchange contracts [Member]
Notional Amount of Derivatives [Abstract]
Derivative Assets, Notional	580,886	[1]	546,572	[2]
Derivative Liabilities, Notional	580,712	[1]	546,405	[2]
Derivative Assets, Fair Value, Net [Abstract]
Derivative Assets, Gross Fair Value	494,349		498,830
Derivative Assets, Netting Adjustments	0		0
Derivative Assets, Net Fair Value Before Cash Collateral	494,349		498,830
Derivative Assets, Fair Value, Cash Collateral	(5,183)		(4,140)
Derivative contracts, net of cash margin, Assets, Fair Value	489,166		494,690
Derivative Liabilities, Fair Value, Net [Abstract]
Derivative Liabilities, Fair Value, Gross Liability	494,695		498,574
Derivative Liabilities, Netting Adjustments	0		0
Derivative Liabilities, Net Fair Value Before Cash Collateral	494,695		498,574
Derivative Liabilities, Fair Value, Cash Collateral	(3,630)		(1,951)
Derivative contracts, net of cash margin, Liabilities, Fair Value	491,065		496,623
Not Designated as Hedging Instrument [Member] | Equity option contracts [Member]
Notional Amount of Derivatives [Abstract]
Derivative Assets, Notional	100,924	[1]	137,278	[2]
Derivative Liabilities, Notional	100,924	[1]	137,278	[2]
Derivative Assets, Fair Value, Net [Abstract]
Derivative Assets, Gross Fair Value	4,357		3,780
Derivative Assets, Netting Adjustments	0		0
Derivative Assets, Net Fair Value Before Cash Collateral	4,357		3,780
Derivative Assets, Fair Value, Cash Collateral	(730)		(470)
Derivative contracts, net of cash margin, Assets, Fair Value	3,627		3,310
Derivative Liabilities, Fair Value, Net [Abstract]
Derivative Liabilities, Fair Value, Gross Liability	4,357		3,780
Derivative Liabilities, Netting Adjustments	0		0
Derivative Liabilities, Net Fair Value Before Cash Collateral	4,357		3,780
Derivative Liabilities, Fair Value, Cash Collateral	0		0
Derivative contracts, net of cash margin, Liabilities, Fair Value	4,357		3,780
Not Designated as Hedging Instrument [Member] | Customer risk management programs [Member]
Notional Amount of Derivatives [Abstract]
Derivative Assets, Notional	19,923,145	[1]	17,131,221	[2]
Derivative Liabilities, Notional	19,596,157	[1]	16,710,014	[2]
Derivative Assets, Fair Value, Net [Abstract]
Derivative Assets, Gross Fair Value	779,365		663,260
Derivative Assets, Netting Adjustments	(89,368)		(52,433)
Derivative Assets, Net Fair Value Before Cash Collateral	689,997		610,827
Derivative Assets, Fair Value, Cash Collateral	(10,551)		(24,640)
Derivative contracts, net of cash margin, Assets, Fair Value	679,446		586,187
Derivative Liabilities, Fair Value, Net [Abstract]
Derivative Liabilities, Fair Value, Gross Liability	776,093		658,871
Derivative Liabilities, Netting Adjustments	(89,368)		(52,433)
Derivative Liabilities, Net Fair Value Before Cash Collateral	686,725		606,438
Derivative Liabilities, Fair Value, Cash Collateral	(47,910)		(25,037)
Derivative contracts, net of cash margin, Liabilities, Fair Value	638,815		581,401
Not Designated as Hedging Instrument [Member] | Internal risk management programs [Member]
Notional Amount of Derivatives [Abstract]
Derivative Assets, Notional	2,514,169	[1]	22,000	[2]
Derivative Liabilities, Notional	2,582,202	[1]	75,000	[2]
Derivative Assets, Fair Value, Net [Abstract]
Derivative Assets, Gross Fair Value	10,426		83
Derivative Assets, Netting Adjustments	0		0
Derivative Assets, Net Fair Value Before Cash Collateral	10,426		83
Derivative Assets, Fair Value, Cash Collateral	0		0
Derivative contracts, net of cash margin, Assets, Fair Value	10,426		83
Derivative Liabilities, Fair Value, Net [Abstract]
Derivative Liabilities, Fair Value, Gross Liability	25,716		300
Derivative Liabilities, Netting Adjustments	0		0
Derivative Liabilities, Net Fair Value Before Cash Collateral	25,716		300
Derivative Liabilities, Fair Value, Cash Collateral	0		0
Derivative contracts, net of cash margin, Liabilities, Fair Value	$ 25,716		$ 300
[1]	Notional amounts for commodity contracts are converted into dollar-equivalent amounts based on dollar prices at the inception of the contract.
[2]	Notional amounts for commodity contracts are converted into dollar-equivalent amounts based on dollar prices at the inception of the contract.

Loans and Allowances for Cred62

Loans and Allowances for Credit Losses, Loans by Portfolio Segment (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015
Loans receivables disclosure [Abstract]
Loans receivables with fixed rate of interest		$ 4,753,600	$ 4,169,034
Loans receivables with variable rate of interest		12,005,076	11,624,992
Loan receivable non-accrual		230,984	147,128
Total		16,989,660	15,941,154
Accruing loans past due (90 days)	[1]	5	1,207
Foregone interest on nonaccrual loans		15,990	7,432
Credit Commitments [Abstract]
Outstanding commitments to extend credit		9,400,000
Outstanding standby letters of credit		585,000
Outstanding commercial letters of credit		4,200
Geographic Concentration Risk [Member] | Texas [Member]
Loans receivables disclosure [Abstract]
Total		$ 5,400,000	$ 5,300,000
Loans receivable, other information [Abstract]
Percentage of loan portfolio attributed to Texas		32.00%	33.00%
Geographic Concentration Risk [Member] | Oklahoma [Member]
Loans receivables disclosure [Abstract]
Total		$ 3,500,000	$ 3,900,000
Loans receivable, other information [Abstract]
Percentage of loan portfolio attributed to Oklahoma		21.00%	24.00%
Commercial [Member]
Loans receivables disclosure [Abstract]
Loans receivables with fixed rate of interest		$ 2,327,085	$ 1,850,548
Loans receivables with variable rate of interest		7,884,786	8,325,559
Loan receivable non-accrual		178,953	76,424
Total		10,390,824	10,252,531
Commercial [Member] | Geographic Concentration Risk [Member] | Texas [Member]
Loans receivables disclosure [Abstract]
Total		$ 3,300,000	$ 3,500,000
Loans receivable, other information [Abstract]
Percentage of loan portfolio attributed to Texas		32.00%	34.00%
Commercial [Member] | Geographic Concentration Risk [Member] | Oklahoma [Member]
Loans receivables disclosure [Abstract]
Total		$ 2,100,000	$ 2,500,000
Loans receivable, other information [Abstract]
Percentage of loan portfolio attributed to Oklahoma		21.00%	24.00%
Commercial [Member] | Services [Member]
Loans receivables disclosure [Abstract]
Total		$ 3,108,990	$ 2,784,276
Commercial [Member] | Services [Member] | Credit Concentration Risk [Member]
Loans receivables disclosure [Abstract]
Total		$ 3,100,000	$ 2,800,000
Loans receivable, other information [Abstract]
Percentage of loan class to total loans		18.00%	17.00%
Amount of loans with individual balances less than $10 million		$ 1,400,000	$ 1,200,000
Maximum loan amount for certain individual loans in category		10,000	10,000
Commercial [Member] | Energy [Member]
Loans receivables disclosure [Abstract]
Total		2,497,868	3,097,328
Commercial [Member] | Energy [Member] | Credit Concentration Risk [Member]
Loans receivables disclosure [Abstract]
Total		$ 2,500,000	$ 3,100,000
Loans receivable, other information [Abstract]
Percentage of loan class to total loans		15.00%	19.00%
Commercial [Member] | Energy Producers [Member] | Credit Concentration Risk [Member]
Loans receivables disclosure [Abstract]
Total		$ 2,000,000	$ 2,500,000
Loans receivable, other information [Abstract]
Percentage of committed energy production loans secured by oil		57.00%	62.00%
Percentage of committed energy production loans secured by natural gas		43.00%	38.00%
Commercial [Member] | Healthcare [Member]
Loans receivables disclosure [Abstract]
Total		$ 2,201,916	$ 1,883,380
Commercial [Member] | Healthcare [Member] | Credit Concentration Risk [Member]
Loans receivables disclosure [Abstract]
Total		$ 2,200,000	$ 1,900,000
Loans receivable, other information [Abstract]
Percentage of loan class to total loans		13.00%	12.00%
Commercial Real Estate [Member]
Loans receivables disclosure [Abstract]
Loans receivables with fixed rate of interest		$ 624,187	$ 627,678
Loans receivables with variable rate of interest		3,179,338	2,622,354
Loan receivable non-accrual		5,521	9,001
Total		$ 3,809,046	$ 3,259,033
Commercial Real Estate [Member] | Geographic Concentration Risk [Member] | Texas [Member]
Loans receivable, other information [Abstract]
Percentage of loan portfolio secured by property in Texas (in hundredths)		30.00%	30.00%
Commercial Real Estate [Member] | Geographic Concentration Risk [Member] | Oklahoma [Member]
Loans receivable, other information [Abstract]
Percentage of loan portfolio secured by property in Oklahoma (in hundredths)		11.00%	13.00%
Residential Mortgage [Member]
Loans receivables disclosure [Abstract]
Loans receivables with fixed rate of interest		$ 1,647,357	$ 1,598,992
Loans receivables with variable rate of interest		256,255	216,661
Loan receivable non-accrual		46,220	61,240
Total		$ 1,949,832	$ 1,876,893
Residential Mortgage [Member] | Geographic Concentration Risk [Member] | Texas [Member]
Loans receivable, other information [Abstract]
Percentage of loan portfolio secured by property in Texas (in hundredths)		29.00%	29.00%
Residential Mortgage [Member] | Geographic Concentration Risk [Member] | Oklahoma [Member]
Loans receivable, other information [Abstract]
Percentage of loan portfolio secured by property in Oklahoma (in hundredths)		33.00%	37.00%
Residential Mortgage [Member] | Geographic Concentration Risk [Member] | New Mexico [Memnber]
Loans receivable, other information [Abstract]
Percentage of loan portfolio secured by property in New Mexico (in hundredths)		10.00%	12.00%
Residential Mortgage [Member] | Geographic Concentration Risk [Member] | Colorado [Member]
Loans receivable, other information [Abstract]
Percentage of loan portfolio secured by property in Colorado (in hundredths)		10.00%	9.00%
Residential Mortgage [Member] | Permanent mortgage [Member]
Loans receivables disclosure [Abstract]
Total		$ 1,006,820	$ 945,336
Loans receivable, other information [Abstract]
Minimum FICO required for jumbo loan approval		720
Maximum debt-to-income ratio on jumbo loans (in hundredths)		38.00%
Minimum loan-to-value ratio on jumbo loans (in hundredths)		60.00%
Maximum loan-to-value ratio on jumbo loans (in hundredths)		100.00%
Minimum period for fixed rate on variable rate jumbo loans (in years)		3 years
Maximum period for fixed rate on variable rate jumbo loans (in years)		10 years
Residential Mortgage [Member] | Permanent mortgages guaranteed by U.S. government agencies [Member]
Loans receivables disclosure [Abstract]
Total		$ 199,387	196,937
Residential Mortgage [Member] | Home equity [Member]
Loans receivables disclosure [Abstract]
Total		743,625	$ 734,620
Loans receivable, other information [Abstract]
Maximum loan amount for certain individual loans in category		$ 400
Percentage of home equity portfolio comprised of first lien loans		65.00%	68.00%
Percentage of home equity portfolio comprised of junior lien loans		35.00%	32.00%
Percentage of junior lien home equity loans that are amortizing term loans		52.00%	65.00%
Percentage of junior lien home equity loans that are revolving lines of credit		48.00%	35.00%
Home equity loans, description		Home equity loans generally require a minimum FICO score of 700 and a maximum DTI of 40%.
Home equity loans, revolving period		5 years
Home equity loans, amortization period following revolving period		15 years
Home equity loans, discretionary additional revolving period		5 years
Personal [Member]
Loans receivables disclosure [Abstract]
Loans receivables with fixed rate of interest		$ 154,971	$ 91,816
Loans receivables with variable rate of interest		684,697	460,418
Loan receivable non-accrual		290	463
Total		$ 839,958	$ 552,697
[1]	Excludes residential mortgage loans guaranteed by agencies of the U.S. government

Derivatives, Derivatives Instru

Derivatives, Derivatives Instruments Gain (Loss) in Income Statement (Details) - Not Designated as Hedging Instrument [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Trading Activity, Gains and Losses, Net [Line Items]
Brokerage and Trading Revenue	$ 42,603	$ 40,714	$ 37,800
Gain (Loss) on Derivatives, Net	(15,685)	430	2,776
To-be-announced residential mortgage-backed securities [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Brokerage and Trading Revenue	38,523	33,877	27,007
Gain (Loss) on Derivatives, Net	0	0	0
Interest rate swaps [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Brokerage and Trading Revenue	2,589	2,066	2,494
Gain (Loss) on Derivatives, Net	0	0	0
Energy contracts [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Brokerage and Trading Revenue	5,027	4,060	6,572
Gain (Loss) on Derivatives, Net	0	0	0
Agricultural contracts [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Brokerage and Trading Revenue	111	123	146
Gain (Loss) on Derivatives, Net	0	0	0
Foreign exchange contracts [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Brokerage and Trading Revenue	945	797	1,581
Gain (Loss) on Derivatives, Net	0	0	0
Equity option contracts [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Brokerage and Trading Revenue	0	0	0
Gain (Loss) on Derivatives, Net	0	0	0
Customer risk management programs [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Brokerage and Trading Revenue	47,195	40,923	37,800
Gain (Loss) on Derivatives, Net	0	0	0
Internal risk management programs [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Brokerage and Trading Revenue	(4,592)	(209)	0
Gain (Loss) on Derivatives, Net	$ (15,685)	$ 430	$ 2,776

Loans and Allowances for Cred64

Loans and Allowances for Credit Losses, Activity in Allowance for Credit Losses (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2016	Dec. 31, 2015
Allowance for loan losses [Roll Forward]
Beginning balance	$ 225,524	$ 189,056	$ 185,396
Provision for loan losses	55,467	33,519	858
Loans charged off	(42,588)	(15,171)	(16,232)
Recoveries	7,756	18,120	19,034
Ending balance	246,159	225,524	189,056
Accrual for off-balance sheet credit losses [Roll Forward]
Beginning balance	1,711	1,230	2,088
Provision for off-balance sheet credit risk	9,533	481	(858)
Ending balance	11,244	1,711	1,230
Total provision for credit losses	65,000	34,000	0
Recorded investment [Abstract]
Collectively measured for impairment, recorded investment				$ 16,758,676	$ 15,794,026
Individually measured for impairment, recorded investment				230,984	147,128
Total				16,989,660	15,941,154
Related allowance [Abstract]
Collectively measured for impairment, related allowance				217,116	179,005
Individually measured for impairment, related allowance				843	16,393
Total measured for impairment, related allowance	225,524	189,056	185,396	246,159	225,524
Commercial [Member]
Allowance for loan losses [Roll Forward]
Beginning balance	130,334	90,875	79,180
Provision for loan losses	43,980	43,464	9,561
Loans charged off	(35,828)	(6,734)	(3,569)
Recoveries	1,727	2,729	5,703
Ending balance	140,213	130,334	90,875
Accrual for off-balance sheet credit losses [Roll Forward]
Beginning balance	1,506	475	119
Provision for off-balance sheet credit risk	9,557	1,031	356
Ending balance	11,063	1,506	475
Total provision for credit losses	53,537	44,495	9,917
Recorded investment [Abstract]
Collectively measured for impairment, recorded investment				10,211,871	10,176,107
Individually measured for impairment, recorded investment				178,953	76,424
Total				10,390,824	10,252,531
Related allowance [Abstract]
Collectively measured for impairment, related allowance				139,416	114,027
Individually measured for impairment, related allowance				797	16,307
Total measured for impairment, related allowance	130,334	90,875	79,180	140,213	130,334
Commercial Real Estate [Member]
Allowance for loan losses [Roll Forward]
Beginning balance	41,391	42,445	41,573
Provision for loan losses	8,075	(11,189)	(4,084)
Loans charged off	0	(944)	(2,047)
Recoveries	1,283	11,079	7,003
Ending balance	50,749	41,391	42,445
Accrual for off-balance sheet credit losses [Roll Forward]
Beginning balance	153	707	1,876
Provision for off-balance sheet credit risk	(30)	(554)	(1,169)
Ending balance	123	153	707
Total provision for credit losses	8,045	(11,743)	(5,253)
Recorded investment [Abstract]
Collectively measured for impairment, recorded investment				3,803,525	3,250,032
Individually measured for impairment, recorded investment				5,521	9,001
Total				3,809,046	3,259,033
Related allowance [Abstract]
Collectively measured for impairment, related allowance				50,749	41,373
Individually measured for impairment, related allowance				0	18
Total measured for impairment, related allowance	41,391	42,445	41,573	50,749	41,391
Residential Mortgage [Member]
Allowance for loan losses [Roll Forward]
Beginning balance	19,509	23,458	29,465
Provision for loan losses	(1,972)	(3,004)	(3,559)
Loans charged off	(1,312)	(2,205)	(4,448)
Recoveries	1,999	1,260	2,000
Ending balance	18,224	19,509	23,458
Accrual for off-balance sheet credit losses [Roll Forward]
Beginning balance	30	28	90
Provision for off-balance sheet credit risk	20	2	(62)
Ending balance	50	30	28
Total provision for credit losses	(1,952)	(3,002)	(3,621)
Recorded investment [Abstract]
Collectively measured for impairment, recorded investment				1,903,612	1,815,653
Individually measured for impairment, recorded investment				46,220	61,240
Total				1,949,832	1,876,893
Related allowance [Abstract]
Collectively measured for impairment, related allowance				18,178	19,441
Individually measured for impairment, related allowance				46	68
Total measured for impairment, related allowance	19,509	23,458	29,465	18,224	19,509
Personal [Member]
Allowance for loan losses [Roll Forward]
Beginning balance	4,164	4,233	6,965
Provision for loan losses	7,310	2,167	(892)
Loans charged off	(5,448)	(5,288)	(6,168)
Recoveries	2,747	3,052	4,328
Ending balance	8,773	4,164	4,233
Accrual for off-balance sheet credit losses [Roll Forward]
Beginning balance	22	20	3
Provision for off-balance sheet credit risk	(14)	2	17
Ending balance	8	22	20
Total provision for credit losses	7,296	2,169	(875)
Recorded investment [Abstract]
Collectively measured for impairment, recorded investment				839,668	552,234
Individually measured for impairment, recorded investment				290	463
Total				839,958	552,697
Related allowance [Abstract]
Collectively measured for impairment, related allowance				8,773	4,164
Individually measured for impairment, related allowance				0	0
Total measured for impairment, related allowance	4,164	4,233	6,965	8,773	4,164
Specific Allowance [Member]
Allowance for loan losses [Roll Forward]
Beginning balance	195,398
Ending balance	217,959	195,398
Recorded investment [Abstract]
Collectively measured for impairment, recorded investment				16,758,676	15,794,026
Individually measured for impairment, recorded investment				230,984	147,128
Total				16,989,660	15,941,154
Related allowance [Abstract]
Collectively measured for impairment, related allowance				217,116	179,005
Individually measured for impairment, related allowance				843	16,393
Total measured for impairment, related allowance	195,398	195,398		217,959	195,398
Nonspecific Allowance [Member]
Allowance for loan losses [Roll Forward]
Beginning balance	30,126	28,045	28,213
Provision for loan losses	(1,926)	2,081	(168)
Loans charged off	0	0	0
Recoveries	0	0	0
Ending balance	28,200	30,126	28,045
Accrual for off-balance sheet credit losses [Roll Forward]
Beginning balance	0	0	0
Provision for off-balance sheet credit risk	0	0	0
Ending balance	0	0	0
Total provision for credit losses	(1,926)	2,081	(168)
Recorded investment [Abstract]
Collectively measured for impairment, recorded investment				0	0
Individually measured for impairment, recorded investment				0	0
Total				0	0
Related allowance [Abstract]
Collectively measured for impairment, related allowance				0	0
Individually measured for impairment, related allowance				0	0
Total measured for impairment, related allowance	$ 30,126	$ 28,045	$ 28,213	$ 28,200	$ 30,126

Loans and Allowances for Cred65

Loans and Allowances for Credit Losses, Credit Quality Indicators (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	$ 15,158,076	$ 14,150,992
Non-Graded, Recorded Investment	1,831,584	1,790,162
Total	16,989,660	15,941,154
Related Allowance [Abstract]
Internally Risk Graded, Related Allowance	197,970	175,090
Non-Graded, Related Allowance	19,989	20,308
Total, Related Allowance	246,159	225,524	$ 189,056	$ 185,396
Commercial [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	10,360,725	10,227,303
Non-Graded, Recorded Investment	30,099	25,228
Total	10,390,824	10,252,531
Related Allowance [Abstract]
Internally Risk Graded, Related Allowance	139,293	129,426
Non-Graded, Related Allowance	920	908
Total, Related Allowance	140,213	130,334	90,875	79,180
Commercial [Member] | Energy [Member]
Recorded Investment [Abstract]
Total	2,497,868	3,097,328
Commercial [Member] | Services [Member]
Recorded Investment [Abstract]
Total	3,108,990	2,784,276
Commercial [Member] | Wholesale/retail [Member]
Recorded Investment [Abstract]
Total	1,576,818	1,422,064
Commercial [Member] | Manufacturing [Member]
Recorded Investment [Abstract]
Total	514,975	556,729
Commercial [Member] | Healthcare [Member]
Recorded Investment [Abstract]
Total	2,201,916	1,883,380
Commercial [Member] | Other commercial and industrial [Member]
Recorded Investment [Abstract]
Total	490,257	508,754
Commercial Real Estate [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	3,809,046	3,259,033
Non-Graded, Recorded Investment	0	0
Total	3,809,046	3,259,033
Related Allowance [Abstract]
Internally Risk Graded, Related Allowance	50,749	41,391
Non-Graded, Related Allowance	0	0
Total, Related Allowance	50,749	41,391	42,445	41,573
Commercial Real Estate [Member] | Residential construction and land development [Member]
Recorded Investment [Abstract]
Total	135,533	160,426
Commercial Real Estate [Member] | Retail [Member]
Recorded Investment [Abstract]
Total	761,888	796,499
Commercial Real Estate [Member] | Office [Member]
Recorded Investment [Abstract]
Total	798,888	637,707
Commercial Real Estate [Member] | Multifamily [Member]
Recorded Investment [Abstract]
Total	903,272	751,085
Commercial Real Estate [Member] | Industrial [Member]
Recorded Investment [Abstract]
Total	871,749	563,169
Commercial Real Estate [Member] | Other commercial real estate [Member]
Recorded Investment [Abstract]
Total	337,716	350,147
Residential Mortgage [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	243,703	196,701
Non-Graded, Recorded Investment	1,706,129	1,680,192
Total	1,949,832	1,876,893
Related Allowance [Abstract]
Internally Risk Graded, Related Allowance	2,893	2,883
Non-Graded, Related Allowance	15,331	16,626
Total, Related Allowance	18,224	19,509	23,458	29,465
Residential Mortgage [Member] | Permanent mortgage [Member]
Recorded Investment [Abstract]
Total	1,006,820	945,336
Residential Mortgage [Member] | Permanent mortgages guaranteed by U.S. government agencies [Member]
Recorded Investment [Abstract]
Total	199,387	196,937
Residential Mortgage [Member] | Home equity [Member]
Recorded Investment [Abstract]
Total	743,625	734,620
Personal [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	744,602	467,955
Non-Graded, Recorded Investment	95,356	84,742
Total	839,958	552,697
Related Allowance [Abstract]
Internally Risk Graded, Related Allowance	5,035	1,390
Non-Graded, Related Allowance	3,738	2,774
Total, Related Allowance	8,773	4,164	4,233	6,965
Specific Allowance [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	15,158,076	14,150,992
Non-Graded, Recorded Investment	1,831,584	1,790,162
Total	16,989,660	15,941,154
Related Allowance [Abstract]
Internally Risk Graded, Related Allowance	197,970	175,090
Non-Graded, Related Allowance	19,989	20,308
Total, Related Allowance	217,959	195,398
Nonspecific Allowance [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	0	0
Non-Graded, Recorded Investment	0	0
Total	0	0
Related Allowance [Abstract]
Internally Risk Graded, Related Allowance	0	0
Non-Graded, Related Allowance	0	0
Total, Related Allowance	28,200	30,126	$ 28,045	$ 28,213
Performing [Member]
Recorded Investment [Abstract]
Non-Graded, Recorded Investment	1,786,530	1,730,775
Performing [Member] | Commercial [Member]
Recorded Investment [Abstract]
Non-Graded, Recorded Investment	30,041	25,101
Performing [Member] | Commercial [Member] | Energy [Member]
Recorded Investment [Abstract]
Non-Graded, Recorded Investment	0	0
Performing [Member] | Commercial [Member] | Services [Member]
Recorded Investment [Abstract]
Non-Graded, Recorded Investment	0	0
Performing [Member] | Commercial [Member] | Wholesale/retail [Member]
Recorded Investment [Abstract]
Non-Graded, Recorded Investment	0	0
Performing [Member] | Commercial [Member] | Manufacturing [Member]
Recorded Investment [Abstract]
Non-Graded, Recorded Investment	0	0
Performing [Member] | Commercial [Member] | Healthcare [Member]
Recorded Investment [Abstract]
Non-Graded, Recorded Investment	0	0
Performing [Member] | Commercial [Member] | Other commercial and industrial [Member]
Recorded Investment [Abstract]
Non-Graded, Recorded Investment	30,041	25,101
Performing [Member] | Commercial Real Estate [Member]
Recorded Investment [Abstract]
Non-Graded, Recorded Investment	0	0
Performing [Member] | Commercial Real Estate [Member] | Residential construction and land development [Member]
Recorded Investment [Abstract]
Non-Graded, Recorded Investment	0	0
Performing [Member] | Commercial Real Estate [Member] | Retail [Member]
Recorded Investment [Abstract]
Non-Graded, Recorded Investment	0	0
Performing [Member] | Commercial Real Estate [Member] | Office [Member]
Recorded Investment [Abstract]
Non-Graded, Recorded Investment	0	0
Performing [Member] | Commercial Real Estate [Member] | Multifamily [Member]
Recorded Investment [Abstract]
Non-Graded, Recorded Investment	0	0
Performing [Member] | Commercial Real Estate [Member] | Industrial [Member]
Recorded Investment [Abstract]
Non-Graded, Recorded Investment	0	0
Performing [Member] | Commercial Real Estate [Member] | Other commercial real estate [Member]
Recorded Investment [Abstract]
Non-Graded, Recorded Investment	0	0
Performing [Member] | Residential Mortgage [Member]
Recorded Investment [Abstract]
Non-Graded, Recorded Investment	1,661,326	1,621,265
Performing [Member] | Residential Mortgage [Member] | Permanent mortgage [Member]
Recorded Investment [Abstract]
Non-Graded, Recorded Investment	741,679	721,964
Performing [Member] | Residential Mortgage [Member] | Permanent mortgages guaranteed by U.S. government agencies [Member]
Recorded Investment [Abstract]
Non-Graded, Recorded Investment	187,541	175,037
Performing [Member] | Residential Mortgage [Member] | Home equity [Member]
Recorded Investment [Abstract]
Non-Graded, Recorded Investment	732,106	724,264
Performing [Member] | Personal [Member]
Recorded Investment [Abstract]
Non-Graded, Recorded Investment	95,163	84,409
Performing [Member] | Pass [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	14,343,507	13,523,199
Performing [Member] | Pass [Member] | Commercial [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	9,567,816	9,628,481
Performing [Member] | Pass [Member] | Commercial [Member] | Energy [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	1,937,790	2,580,694
Performing [Member] | Pass [Member] | Commercial [Member] | Services [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	3,052,002	2,763,929
Performing [Member] | Pass [Member] | Commercial [Member] | Wholesale/retail [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	1,535,463	1,394,596
Performing [Member] | Pass [Member] | Commercial [Member] | Manufacturing [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	468,314	534,966
Performing [Member] | Pass [Member] | Commercial [Member] | Healthcare [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	2,140,458	1,876,745
Performing [Member] | Pass [Member] | Commercial [Member] | Other commercial and industrial [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	433,789	477,551
Performing [Member] | Pass [Member] | Commercial Real Estate [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	3,793,471	3,234,543
Performing [Member] | Pass [Member] | Commercial Real Estate [Member] | Residential construction and land development [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	131,630	154,369
Performing [Member] | Pass [Member] | Commercial Real Estate [Member] | Retail [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	756,418	788,708
Performing [Member] | Pass [Member] | Commercial Real Estate [Member] | Office [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	798,462	636,210
Performing [Member] | Pass [Member] | Commercial Real Estate [Member] | Multifamily [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	898,800	744,299
Performing [Member] | Pass [Member] | Commercial Real Estate [Member] | Industrial [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	871,673	563,093
Performing [Member] | Pass [Member] | Commercial Real Estate [Member] | Other commercial real estate [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	336,488	347,864
Performing [Member] | Pass [Member] | Residential Mortgage [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	238,769	192,367
Performing [Member] | Pass [Member] | Residential Mortgage [Member] | Permanent mortgage [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	238,769	192,367
Performing [Member] | Pass [Member] | Residential Mortgage [Member] | Permanent mortgages guaranteed by U.S. government agencies [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	0	0
Performing [Member] | Pass [Member] | Residential Mortgage [Member] | Home equity [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	0	0
Performing [Member] | Pass [Member] | Personal [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	743,451	467,808
Performing [Member] | Other Loans Especially Mentioned [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	229,673	385,529
Performing [Member] | Other Loans Especially Mentioned [Member] | Commercial [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	223,742	377,745
Performing [Member] | Other Loans Especially Mentioned [Member] | Commercial [Member] | Energy [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	119,583	325,663
Performing [Member] | Other Loans Especially Mentioned [Member] | Commercial [Member] | Services [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	10,960	3,296
Performing [Member] | Other Loans Especially Mentioned [Member] | Commercial [Member] | Wholesale/retail [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	16,886	18,184
Performing [Member] | Other Loans Especially Mentioned [Member] | Commercial [Member] | Manufacturing [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	26,532	19,560
Performing [Member] | Other Loans Especially Mentioned [Member] | Commercial [Member] | Healthcare [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	44,472	5,563
Performing [Member] | Other Loans Especially Mentioned [Member] | Commercial [Member] | Other commercial and industrial [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	5,309	5,479
Performing [Member] | Other Loans Especially Mentioned [Member] | Commercial Real Estate [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	4,745	7,692
Performing [Member] | Other Loans Especially Mentioned [Member] | Commercial Real Estate [Member] | Residential construction and land development [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	0	1,355
Performing [Member] | Other Loans Especially Mentioned [Member] | Commercial Real Estate [Member] | Retail [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	4,745	6,046
Performing [Member] | Other Loans Especially Mentioned [Member] | Commercial Real Estate [Member] | Office [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	0	291
Performing [Member] | Other Loans Especially Mentioned [Member] | Commercial Real Estate [Member] | Multifamily [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	0	0
Performing [Member] | Other Loans Especially Mentioned [Member] | Commercial Real Estate [Member] | Industrial [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	0	0
Performing [Member] | Other Loans Especially Mentioned [Member] | Commercial Real Estate [Member] | Other commercial real estate [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	0	0
Performing [Member] | Other Loans Especially Mentioned [Member] | Residential Mortgage [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	1,186	89
Performing [Member] | Other Loans Especially Mentioned [Member] | Residential Mortgage [Member] | Permanent mortgage [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	1,186	89
Performing [Member] | Other Loans Especially Mentioned [Member] | Residential Mortgage [Member] | Permanent mortgages guaranteed by U.S. government agencies [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	0	0
Performing [Member] | Other Loans Especially Mentioned [Member] | Residential Mortgage [Member] | Home equity [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	0	0
Performing [Member] | Other Loans Especially Mentioned [Member] | Personal [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	0	3
Performing [Member] | Substandard [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	398,966	154,523
Performing [Member] | Substandard [Member] | Commercial [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	390,272	144,780
Performing [Member] | Substandard [Member] | Commercial [Member] | Energy [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	307,996	129,782
Performing [Member] | Substandard [Member] | Commercial [Member] | Services [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	37,855	6,761
Performing [Member] | Substandard [Member] | Commercial [Member] | Wholesale/retail [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	13,062	6,365
Performing [Member] | Substandard [Member] | Commercial [Member] | Manufacturing [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	15,198	1,872
Performing [Member] | Substandard [Member] | Commercial [Member] | Healthcare [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	16,161	0
Performing [Member] | Substandard [Member] | Commercial [Member] | Other commercial and industrial [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	0	0
Performing [Member] | Substandard [Member] | Commercial Real Estate [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	5,309	7,797
Performing [Member] | Substandard [Member] | Commercial Real Estate [Member] | Residential construction and land development [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	470	293
Performing [Member] | Substandard [Member] | Commercial Real Estate [Member] | Retail [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	399	426
Performing [Member] | Substandard [Member] | Commercial Real Estate [Member] | Office [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	0	555
Performing [Member] | Substandard [Member] | Commercial Real Estate [Member] | Multifamily [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	4,434	6,512
Performing [Member] | Substandard [Member] | Commercial Real Estate [Member] | Industrial [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	0	0
Performing [Member] | Substandard [Member] | Commercial Real Estate [Member] | Other commercial real estate [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	6	11
Performing [Member] | Substandard [Member] | Residential Mortgage [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	2,331	1,932
Performing [Member] | Substandard [Member] | Residential Mortgage [Member] | Permanent mortgage [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	2,331	1,932
Performing [Member] | Substandard [Member] | Residential Mortgage [Member] | Permanent mortgages guaranteed by U.S. government agencies [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	0	0
Performing [Member] | Substandard [Member] | Residential Mortgage [Member] | Home equity [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	0	0
Performing [Member] | Substandard [Member] | Personal [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	1,054	14
Nonaccrual [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	185,930	87,741
Non-Graded, Recorded Investment	45,054	59,387
Nonaccrual [Member] | Commercial [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	178,895	76,297
Non-Graded, Recorded Investment	58	127
Nonaccrual [Member] | Commercial [Member] | Energy [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	132,499	61,189
Non-Graded, Recorded Investment	0	0
Nonaccrual [Member] | Commercial [Member] | Services [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	8,173	10,290
Non-Graded, Recorded Investment	0	0
Nonaccrual [Member] | Commercial [Member] | Wholesale/retail [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	11,407	2,919
Non-Graded, Recorded Investment	0	0
Nonaccrual [Member] | Commercial [Member] | Manufacturing [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	4,931	331
Non-Graded, Recorded Investment	0	0
Nonaccrual [Member] | Commercial [Member] | Healthcare [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	825	1,072
Non-Graded, Recorded Investment	0	0
Nonaccrual [Member] | Commercial [Member] | Other commercial and industrial [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	21,060	496
Non-Graded, Recorded Investment	58	127
Nonaccrual [Member] | Commercial Real Estate [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	5,521	9,001
Non-Graded, Recorded Investment	0	0
Nonaccrual [Member] | Commercial Real Estate [Member] | Residential construction and land development [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	3,433	4,409
Non-Graded, Recorded Investment	0	0
Nonaccrual [Member] | Commercial Real Estate [Member] | Retail [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	326	1,319
Non-Graded, Recorded Investment	0	0
Nonaccrual [Member] | Commercial Real Estate [Member] | Office [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	426	651
Non-Graded, Recorded Investment	0	0
Nonaccrual [Member] | Commercial Real Estate [Member] | Multifamily [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	38	274
Non-Graded, Recorded Investment	0	0
Nonaccrual [Member] | Commercial Real Estate [Member] | Industrial [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	76	76
Non-Graded, Recorded Investment	0	0
Nonaccrual [Member] | Commercial Real Estate [Member] | Other commercial real estate [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	1,222	2,272
Non-Graded, Recorded Investment	0	0
Nonaccrual [Member] | Residential Mortgage [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	1,417	2,313
Non-Graded, Recorded Investment	44,803	58,927
Nonaccrual [Member] | Residential Mortgage [Member] | Permanent mortgage [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	1,417	2,313
Non-Graded, Recorded Investment	21,438	26,671
Nonaccrual [Member] | Residential Mortgage [Member] | Permanent mortgages guaranteed by U.S. government agencies [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	0	0
Non-Graded, Recorded Investment	11,846	21,900
Nonaccrual [Member] | Residential Mortgage [Member] | Home equity [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	0	0
Non-Graded, Recorded Investment	11,519	10,356
Nonaccrual [Member] | Personal [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	97	130
Non-Graded, Recorded Investment	$ 193	$ 333

Loans and Allowances for Cred66

Loans and Allowances for Credit Losses, Impaired Loans (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016		Dec. 31, 2015
Impaired loans [Abstract]
Impaired loans, unpaid principal balance	$ 473,526		$ 369,450
Impaired loans, recorded investment, total	418,525		322,165
Impaired loans, recorded investment with no related allowance	407,363		278,245
Impaired loans, recorded investment with related allowance	11,162		43,920
Impaired loans, related allowance	843		16,393
Impaired loans, average recorded investment	349,330		297,971
Impaired loans, interest income recognized	9,014		9,056
Commercial [Member]
Impaired loans [Abstract]
Impaired loans, unpaid principal balance	211,762		96,262
Impaired loans, recorded investment, total	178,953		76,424
Impaired loans, recorded investment with no related allowance	167,837		32,779
Impaired loans, recorded investment with related allowance	11,116		43,645
Impaired loans, related allowance	797		16,307
Impaired loans, average recorded investment	110,945		44,977
Impaired loans, interest income recognized	0		0
Commercial [Member] | Energy [Member]
Impaired loans [Abstract]
Impaired loans, unpaid principal balance	146,897		63,910
Impaired loans, recorded investment, total	132,499		61,189
Impaired loans, recorded investment with no related allowance	121,418		18,330
Impaired loans, recorded investment with related allowance	11,081		42,859
Impaired loans, related allowance	762		16,115
Impaired loans, average recorded investment	80,100		31,303
Impaired loans, interest income recognized	0		0
Commercial [Member] | Services [Member]
Impaired loans [Abstract]
Impaired loans, unpaid principal balance	11,723		13,449
Impaired loans, recorded investment, total	8,173		10,290
Impaired loans, recorded investment with no related allowance	8,173		9,657
Impaired loans, recorded investment with related allowance	0		633
Impaired loans, related allowance	0		148
Impaired loans, average recorded investment	9,232		7,746
Impaired loans, interest income recognized	0		0
Commercial [Member] | Wholesale/retail [Member]
Impaired loans [Abstract]
Impaired loans, unpaid principal balance	17,669		8,582
Impaired loans, recorded investment, total	11,407		2,919
Impaired loans, recorded investment with no related allowance	11,407		2,907
Impaired loans, recorded investment with related allowance	0		12
Impaired loans, related allowance	0		9
Impaired loans, average recorded investment	7,163		3,534
Impaired loans, interest income recognized	0		0
Commercial [Member] | Manufacturing [Member]
Impaired loans [Abstract]
Impaired loans, unpaid principal balance	5,320		665
Impaired loans, recorded investment, total	4,931		331
Impaired loans, recorded investment with no related allowance	4,931		331
Impaired loans, recorded investment with related allowance	0		0
Impaired loans, related allowance	0		0
Impaired loans, average recorded investment	2,631		391
Impaired loans, interest income recognized	0		0
Commercial [Member] | Healthcare [Member]
Impaired loans [Abstract]
Impaired loans, unpaid principal balance	1,147		1,352
Impaired loans, recorded investment, total	825		1,072
Impaired loans, recorded investment with no related allowance	825		931
Impaired loans, recorded investment with related allowance	0		141
Impaired loans, related allowance	0		35
Impaired loans, average recorded investment	949		1,226
Impaired loans, interest income recognized	0		0
Commercial [Member] | Other commercial and industrial [Member]
Impaired loans [Abstract]
Impaired loans, unpaid principal balance	29,006		8,304
Impaired loans, recorded investment, total	21,118		623
Impaired loans, recorded investment with no related allowance	21,083		623
Impaired loans, recorded investment with related allowance	35		0
Impaired loans, related allowance	35		0
Impaired loans, average recorded investment	10,870		777
Impaired loans, interest income recognized	0		0
Commercial Real Estate [Member]
Impaired loans [Abstract]
Impaired loans, unpaid principal balance	14,427		21,454
Impaired loans, recorded investment, total	5,521		9,001
Impaired loans, recorded investment with no related allowance	5,521		8,842
Impaired loans, recorded investment with related allowance	0		159
Impaired loans, related allowance	0		18
Impaired loans, average recorded investment	7,262		13,778
Impaired loans, interest income recognized	0		0
Commercial Real Estate [Member] | Residential construction and land development [Member]
Impaired loans [Abstract]
Impaired loans, unpaid principal balance	4,951		8,963
Impaired loans, recorded investment, total	3,433		4,409
Impaired loans, recorded investment with no related allowance	3,433		4,409
Impaired loans, recorded investment with related allowance	0		0
Impaired loans, related allowance	0		0
Impaired loans, average recorded investment	3,921		4,854
Impaired loans, interest income recognized	0		0
Commercial Real Estate [Member] | Retail [Member]
Impaired loans [Abstract]
Impaired loans, unpaid principal balance	530		1,923
Impaired loans, recorded investment, total	326		1,319
Impaired loans, recorded investment with no related allowance	326		1,319
Impaired loans, recorded investment with related allowance	0		0
Impaired loans, related allowance	0		0
Impaired loans, average recorded investment	823		2,622
Impaired loans, interest income recognized	0		0
Commercial Real Estate [Member] | Office [Member]
Impaired loans [Abstract]
Impaired loans, unpaid principal balance	521		937
Impaired loans, recorded investment, total	426		651
Impaired loans, recorded investment with no related allowance	426		651
Impaired loans, recorded investment with related allowance	0		0
Impaired loans, related allowance	0		0
Impaired loans, average recorded investment	539		2,035
Impaired loans, interest income recognized	0		0
Commercial Real Estate [Member] | Multifamily [Member]
Impaired loans [Abstract]
Impaired loans, unpaid principal balance	1,000		1,192
Impaired loans, recorded investment, total	38		274
Impaired loans, recorded investment with no related allowance	38		274
Impaired loans, recorded investment with related allowance	0		0
Impaired loans, related allowance	0		0
Impaired loans, average recorded investment	156		137
Impaired loans, interest income recognized	0		0
Commercial Real Estate [Member] | Industrial [Member]
Impaired loans [Abstract]
Impaired loans, unpaid principal balance	76		76
Impaired loans, recorded investment, total	76		76
Impaired loans, recorded investment with no related allowance	76		76
Impaired loans, recorded investment with related allowance	0		0
Impaired loans, related allowance	0		0
Impaired loans, average recorded investment	76		38
Impaired loans, interest income recognized	0		0
Commercial Real Estate [Member] | Other commercial real estate [Member]
Impaired loans [Abstract]
Impaired loans, unpaid principal balance	7,349		8,363
Impaired loans, recorded investment, total	1,222		2,272
Impaired loans, recorded investment with no related allowance	1,222		2,113
Impaired loans, recorded investment with related allowance	0		159
Impaired loans, related allowance	0		18
Impaired loans, average recorded investment	1,747		4,092
Impaired loans, interest income recognized	0		0
Residential Mortgage [Member]
Impaired loans [Abstract]
Impaired loans, unpaid principal balance	247,005		251,245
Impaired loans, recorded investment, total	233,761		236,277
Impaired loans, recorded investment with no related allowance	233,715		236,161
Impaired loans, recorded investment with related allowance	46		116
Impaired loans, related allowance	46		68
Impaired loans, average recorded investment	230,746		238,701
Impaired loans, interest income recognized	9,014		9,056
Residential Mortgage [Member] | Permanent mortgage [Member]
Impaired loans [Abstract]
Impaired loans, unpaid principal balance	28,830		37,273
Impaired loans, recorded investment, total	22,855		28,984
Impaired loans, recorded investment with no related allowance	22,809		28,868
Impaired loans, recorded investment with related allowance	46		116
Impaired loans, related allowance	46		68
Impaired loans, average recorded investment	25,920		31,914
Impaired loans, interest income recognized	1,255		1,242
Residential Mortgage [Member] | Permanent mortgages guaranteed by U.S. government agencies [Member]
Impaired loans [Abstract]
Impaired loans, unpaid principal balance	205,564	[1]	202,984	[2]
Impaired loans, recorded investment, total	199,387	[1]	196,937	[2]
Impaired loans, recorded investment with no related allowance	199,387	[1]	196,937	[2]
Impaired loans, recorded investment with related allowance	0	[1]	0	[2]
Impaired loans, related allowance	0	[1]	0	[2]
Impaired loans, average recorded investment	193,889	[1]	196,827	[2]
Impaired loans, interest income recognized	7,759	[1]	7,814	[2]
Residential Mortgage [Member] | Home equity [Member]
Impaired loans [Abstract]
Impaired loans, unpaid principal balance	12,611		10,988
Impaired loans, recorded investment, total	11,519		10,356
Impaired loans, recorded investment with no related allowance	11,519		10,356
Impaired loans, recorded investment with related allowance	0		0
Impaired loans, related allowance	0		0
Impaired loans, average recorded investment	10,937		9,960
Impaired loans, interest income recognized	0		0
Personal [Member]
Impaired loans [Abstract]
Impaired loans, unpaid principal balance	332		489
Impaired loans, recorded investment, total	290		463
Impaired loans, recorded investment with no related allowance	290		463
Impaired loans, recorded investment with related allowance	0		0
Impaired loans, related allowance	0		0
Impaired loans, average recorded investment	377		515
Impaired loans, interest income recognized	$ 0		$ 0
[1]	All permanent mortgage loans guaranteed by U.S. government agencies are considered impaired as we do not expect full collection of contractual principal and interest. At December 31, 2016, $12 million of these loans are nonaccruing and $188 million are accruing based on the guarantee by U.S. government agencies.
[2]	All permanent mortgage loans guaranteed by U.S. government agencies are considered impaired as we do not expect full collection of contractual principal and interest. At December 31, 2015, $22 million of these loans are nonaccruing and $175 million are accruing based on the guarantee by U.S. government agencies.

Loans and Allowances for Cred67

Loans and Allowances for Credit Losses, Troubled Debt Restructurings (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Financing Receivable, Modifications [Line Items]
Troubled Debt Restructuring, Recorded Investment	$ 147,117	$ 127,684
Troubled Debt Restructuring, Performing in Accordance With Modified Terms	74,738	54,131
Troubled Debt Restructuring, Not Performing in Accordance With Modified Terms	72,379	73,553
Troubled Debt Restructuring, Specific allowance	46	225
Troubled Debt Restructuring, Charge-offs	4,732	1,211
Nonaccrual [Member]
Financing Receivable, Modifications [Line Items]
Troubled Debt Restructuring, Recorded Investment	65,747	53,634
Troubled Debt Restructuring, Performing in Accordance With Modified Terms	47,449	31,102
Troubled Debt Restructuring, Not Performing in Accordance With Modified Terms	18,298	22,532
Troubled Debt Restructuring, Specific allowance	46	225
Troubled Debt Restructuring, Charge-offs	4,732	1,211
Nonaccrual [Member] | Commercial [Member]
Financing Receivable, Modifications [Line Items]
Troubled Debt Restructuring, Recorded Investment	36,879	15,665
Troubled Debt Restructuring, Performing in Accordance With Modified Terms	29,225	14,264
Troubled Debt Restructuring, Not Performing in Accordance With Modified Terms	7,654	1,401
Troubled Debt Restructuring, Specific allowance	0	157
Troubled Debt Restructuring, Charge-offs	4,401	928
Nonaccrual [Member] | Commercial [Member] | Energy [Member]
Financing Receivable, Modifications [Line Items]
Troubled Debt Restructuring, Recorded Investment	16,893	2,304
Troubled Debt Restructuring, Performing in Accordance With Modified Terms	10,867	2,304
Troubled Debt Restructuring, Not Performing in Accordance With Modified Terms	6,026	0
Troubled Debt Restructuring, Specific allowance	0	0
Troubled Debt Restructuring, Charge-offs	4,401	928
Nonaccrual [Member] | Commercial [Member] | Services [Member]
Financing Receivable, Modifications [Line Items]
Troubled Debt Restructuring, Recorded Investment	7,527	9,027
Troubled Debt Restructuring, Performing in Accordance With Modified Terms	6,830	8,210
Troubled Debt Restructuring, Not Performing in Accordance With Modified Terms	697	817
Troubled Debt Restructuring, Specific allowance	0	148
Troubled Debt Restructuring, Charge-offs	0	0
Nonaccrual [Member] | Commercial [Member] | Wholesale/retail [Member]
Financing Receivable, Modifications [Line Items]
Troubled Debt Restructuring, Recorded Investment	11,291	2,758
Troubled Debt Restructuring, Performing in Accordance With Modified Terms	11,251	2,706
Troubled Debt Restructuring, Not Performing in Accordance With Modified Terms	40	52
Troubled Debt Restructuring, Specific allowance	0	9
Troubled Debt Restructuring, Charge-offs	0	0
Nonaccrual [Member] | Commercial [Member] | Manufacturing [Member]
Financing Receivable, Modifications [Line Items]
Troubled Debt Restructuring, Recorded Investment	224	282
Troubled Debt Restructuring, Performing in Accordance With Modified Terms	224	282
Troubled Debt Restructuring, Not Performing in Accordance With Modified Terms	0	0
Troubled Debt Restructuring, Specific allowance	0	0
Troubled Debt Restructuring, Charge-offs	0	0
Nonaccrual [Member] | Commercial [Member] | Healthcare [Member]
Financing Receivable, Modifications [Line Items]
Troubled Debt Restructuring, Recorded Investment	607	673
Troubled Debt Restructuring, Performing in Accordance With Modified Terms	0	673
Troubled Debt Restructuring, Not Performing in Accordance With Modified Terms	607	0
Troubled Debt Restructuring, Specific allowance	0	0
Troubled Debt Restructuring, Charge-offs	0	0
Nonaccrual [Member] | Commercial [Member] | Other commercial and industrial [Member]
Financing Receivable, Modifications [Line Items]
Troubled Debt Restructuring, Recorded Investment	337	621
Troubled Debt Restructuring, Performing in Accordance With Modified Terms	53	89
Troubled Debt Restructuring, Not Performing in Accordance With Modified Terms	284	532
Troubled Debt Restructuring, Specific allowance	0	0
Troubled Debt Restructuring, Charge-offs	0	0
Nonaccrual [Member] | Commercial Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Troubled Debt Restructuring, Recorded Investment	1,707	4,732
Troubled Debt Restructuring, Performing in Accordance With Modified Terms	1,114	3,141
Troubled Debt Restructuring, Not Performing in Accordance With Modified Terms	593	1,591
Troubled Debt Restructuring, Specific allowance	0	0
Troubled Debt Restructuring, Charge-offs	0	0
Nonaccrual [Member] | Commercial Real Estate [Member] | Residential construction and land development [Member]
Financing Receivable, Modifications [Line Items]
Troubled Debt Restructuring, Recorded Investment	690	2,328
Troubled Debt Restructuring, Performing in Accordance With Modified Terms	97	1,556
Troubled Debt Restructuring, Not Performing in Accordance With Modified Terms	593	772
Troubled Debt Restructuring, Specific allowance	0	0
Troubled Debt Restructuring, Charge-offs	0	0
Nonaccrual [Member] | Commercial Real Estate [Member] | Retail [Member]
Financing Receivable, Modifications [Line Items]
Troubled Debt Restructuring, Recorded Investment	326	1,319
Troubled Debt Restructuring, Performing in Accordance With Modified Terms	326	942
Troubled Debt Restructuring, Not Performing in Accordance With Modified Terms	0	377
Troubled Debt Restructuring, Specific allowance	0	0
Troubled Debt Restructuring, Charge-offs	0	0
Nonaccrual [Member] | Commercial Real Estate [Member] | Office [Member]
Financing Receivable, Modifications [Line Items]
Troubled Debt Restructuring, Recorded Investment	143	165
Troubled Debt Restructuring, Performing in Accordance With Modified Terms	143	165
Troubled Debt Restructuring, Not Performing in Accordance With Modified Terms	0	0
Troubled Debt Restructuring, Specific allowance	0	0
Troubled Debt Restructuring, Charge-offs	0	0
Nonaccrual [Member] | Commercial Real Estate [Member] | Multifamily [Member]
Financing Receivable, Modifications [Line Items]
Troubled Debt Restructuring, Recorded Investment	0	0
Troubled Debt Restructuring, Performing in Accordance With Modified Terms	0	0
Troubled Debt Restructuring, Not Performing in Accordance With Modified Terms	0	0
Troubled Debt Restructuring, Specific allowance	0	0
Troubled Debt Restructuring, Charge-offs	0	0
Nonaccrual [Member] | Commercial Real Estate [Member] | Industrial [Member]
Financing Receivable, Modifications [Line Items]
Troubled Debt Restructuring, Recorded Investment	0	0
Troubled Debt Restructuring, Performing in Accordance With Modified Terms	0	0
Troubled Debt Restructuring, Not Performing in Accordance With Modified Terms	0	0
Troubled Debt Restructuring, Specific allowance	0	0
Troubled Debt Restructuring, Charge-offs	0	0
Nonaccrual [Member] | Commercial Real Estate [Member] | Other commercial real estate [Member]
Financing Receivable, Modifications [Line Items]
Troubled Debt Restructuring, Recorded Investment	548	920
Troubled Debt Restructuring, Performing in Accordance With Modified Terms	548	478
Troubled Debt Restructuring, Not Performing in Accordance With Modified Terms	0	442
Troubled Debt Restructuring, Specific allowance	0	0
Troubled Debt Restructuring, Charge-offs	0	0
Nonaccrual [Member] | Residential Mortgage [Member]
Financing Receivable, Modifications [Line Items]
Troubled Debt Restructuring, Recorded Investment	26,924	32,913
Troubled Debt Restructuring, Performing in Accordance With Modified Terms	16,874	13,400
Troubled Debt Restructuring, Not Performing in Accordance With Modified Terms	10,050	19,513
Troubled Debt Restructuring, Specific allowance	46	68
Troubled Debt Restructuring, Charge-offs	258	272
Nonaccrual [Member] | Residential Mortgage [Member] | Permanent mortgage [Member]
Financing Receivable, Modifications [Line Items]
Troubled Debt Restructuring, Recorded Investment	14,876	16,618
Troubled Debt Restructuring, Performing in Accordance With Modified Terms	10,175	9,043
Troubled Debt Restructuring, Not Performing in Accordance With Modified Terms	4,701	7,575
Troubled Debt Restructuring, Specific allowance	46	68
Troubled Debt Restructuring, Charge-offs	28	192
Nonaccrual [Member] | Residential Mortgage [Member] | Permanent mortgages guaranteed by U.S. government agencies [Member]
Financing Receivable, Modifications [Line Items]
Troubled Debt Restructuring, Recorded Investment	6,702	11,136
Troubled Debt Restructuring, Performing in Accordance With Modified Terms	2,241	139
Troubled Debt Restructuring, Not Performing in Accordance With Modified Terms	4,461	10,997
Troubled Debt Restructuring, Specific allowance	0	0
Troubled Debt Restructuring, Charge-offs	0	0
Nonaccrual [Member] | Residential Mortgage [Member] | Home equity [Member]
Financing Receivable, Modifications [Line Items]
Troubled Debt Restructuring, Recorded Investment	5,346	5,159
Troubled Debt Restructuring, Performing in Accordance With Modified Terms	4,458	4,218
Troubled Debt Restructuring, Not Performing in Accordance With Modified Terms	888	941
Troubled Debt Restructuring, Specific allowance	0	0
Troubled Debt Restructuring, Charge-offs	230	80
Nonaccrual [Member] | Personal [Member]
Financing Receivable, Modifications [Line Items]
Troubled Debt Restructuring, Recorded Investment	237	324
Troubled Debt Restructuring, Performing in Accordance With Modified Terms	236	297
Troubled Debt Restructuring, Not Performing in Accordance With Modified Terms	1	27
Troubled Debt Restructuring, Specific allowance	0	0
Troubled Debt Restructuring, Charge-offs	73	11
Accruing [Member]
Financing Receivable, Modifications [Line Items]
Troubled Debt Restructuring, Recorded Investment	81,370	74,050
Troubled Debt Restructuring, Performing in Accordance With Modified Terms	27,289	23,029
Troubled Debt Restructuring, Not Performing in Accordance With Modified Terms	54,081	51,021
Troubled Debt Restructuring, Specific allowance	0	0
Troubled Debt Restructuring, Charge-offs	0	0
Accruing [Member] | Residential Mortgage [Member]
Financing Receivable, Modifications [Line Items]
Troubled Debt Restructuring, Recorded Investment	81,370	74,050
Troubled Debt Restructuring, Performing in Accordance With Modified Terms	27,289	23,029
Troubled Debt Restructuring, Not Performing in Accordance With Modified Terms	54,081	51,021
Troubled Debt Restructuring, Specific allowance	0	0
Troubled Debt Restructuring, Charge-offs	0	0
Accruing [Member] | Residential Mortgage [Member] | Permanent mortgages guaranteed by U.S. government agencies [Member]
Financing Receivable, Modifications [Line Items]
Troubled Debt Restructuring, Recorded Investment	81,370	74,050
Troubled Debt Restructuring, Performing in Accordance With Modified Terms	27,289	23,029
Troubled Debt Restructuring, Not Performing in Accordance With Modified Terms	54,081	51,021
Troubled Debt Restructuring, Specific allowance	0	0
Troubled Debt Restructuring, Charge-offs	$ 0	$ 0

Loans and Allowances for Cred68

Loans and Allowances for Credit Losses, Troubled Debt Restructurings, Modifications (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	$ 52,459	$ 48,420
Troubled Debt Restructurings, Recorded Balance With Payment Default	27,528	34,262
Commercial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	25,995	10,611
Troubled Debt Restructurings, Recorded Balance With Payment Default	8,593	38
Commercial [Member] | Energy [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	16,892	2,304
Troubled Debt Restructurings, Recorded Balance With Payment Default	8,593	0
Commercial [Member] | Services [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	7,577
Troubled Debt Restructurings, Recorded Balance With Payment Default	0	0
Commercial [Member] | Wholesale/retail [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	9,103	0
Troubled Debt Restructurings, Recorded Balance With Payment Default	0	0
Commercial [Member] | Manufacturing [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0
Troubled Debt Restructurings, Recorded Balance With Payment Default	0	0
Commercial [Member] | Healthcare [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	673
Troubled Debt Restructurings, Recorded Balance With Payment Default	0	0
Commercial [Member] | Other commercial and industrial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	57
Troubled Debt Restructurings, Recorded Balance With Payment Default	0	38
Commercial Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	329
Troubled Debt Restructurings, Recorded Balance With Payment Default	0	329
Commercial Real Estate [Member] | Residential construction and land development [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	329
Troubled Debt Restructurings, Recorded Balance With Payment Default	0	329
Commercial Real Estate [Member] | Retail [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0
Troubled Debt Restructurings, Recorded Balance With Payment Default	0	0
Commercial Real Estate [Member] | Office [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0
Troubled Debt Restructurings, Recorded Balance With Payment Default	0	0
Commercial Real Estate [Member] | Multifamily [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0
Troubled Debt Restructurings, Recorded Balance With Payment Default	0	0
Commercial Real Estate [Member] | Industrial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0
Troubled Debt Restructurings, Recorded Balance With Payment Default	0	0
Commercial Real Estate [Member] | Other commercial real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0
Troubled Debt Restructurings, Recorded Balance With Payment Default	0	0
Residential Mortgage [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	26,387	37,365
Troubled Debt Restructurings, Recorded Balance With Payment Default	18,930	33,882
Residential Mortgage [Member] | Permanent mortgage [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	1,364	4,055
Troubled Debt Restructurings, Recorded Balance With Payment Default	544	3,034
Residential Mortgage [Member] | Permanent mortgages guaranteed by U.S. government agencies [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	22,900	31,202
Troubled Debt Restructurings, Recorded Balance With Payment Default	17,801	30,324
Residential Mortgage [Member] | Home equity [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	2,123	2,108
Troubled Debt Restructurings, Recorded Balance With Payment Default	585	524
Personal [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	77	115
Troubled Debt Restructurings, Recorded Balance With Payment Default	5	13
Accruing [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	21,921	28,101
Troubled Debt Restructurings, Recorded Balance With Payment Default	17,154	27,223
Accruing [Member] | Payment Stream [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	11,879	17,717
Accruing [Member] | Combination & Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	10,042	10,384
Accruing [Member] | Commercial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0
Troubled Debt Restructurings, Recorded Balance With Payment Default	0	0
Accruing [Member] | Commercial [Member] | Payment Stream [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0
Accruing [Member] | Commercial [Member] | Combination & Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0
Accruing [Member] | Commercial [Member] | Energy [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0
Troubled Debt Restructurings, Recorded Balance With Payment Default	0	0
Accruing [Member] | Commercial [Member] | Energy [Member] | Payment Stream [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0
Accruing [Member] | Commercial [Member] | Energy [Member] | Combination & Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0
Accruing [Member] | Commercial [Member] | Services [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0
Troubled Debt Restructurings, Recorded Balance With Payment Default	0	0
Accruing [Member] | Commercial [Member] | Services [Member] | Payment Stream [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0
Accruing [Member] | Commercial [Member] | Services [Member] | Combination & Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0
Accruing [Member] | Commercial [Member] | Wholesale/retail [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0
Troubled Debt Restructurings, Recorded Balance With Payment Default	0	0
Accruing [Member] | Commercial [Member] | Wholesale/retail [Member] | Payment Stream [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0
Accruing [Member] | Commercial [Member] | Wholesale/retail [Member] | Combination & Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0
Accruing [Member] | Commercial [Member] | Manufacturing [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0
Troubled Debt Restructurings, Recorded Balance With Payment Default	0	0
Accruing [Member] | Commercial [Member] | Manufacturing [Member] | Payment Stream [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0
Accruing [Member] | Commercial [Member] | Manufacturing [Member] | Combination & Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0
Accruing [Member] | Commercial [Member] | Healthcare [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0
Troubled Debt Restructurings, Recorded Balance With Payment Default	0	0
Accruing [Member] | Commercial [Member] | Healthcare [Member] | Payment Stream [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0
Accruing [Member] | Commercial [Member] | Healthcare [Member] | Combination & Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0
Accruing [Member] | Commercial [Member] | Other commercial and industrial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0
Troubled Debt Restructurings, Recorded Balance With Payment Default	0	0
Accruing [Member] | Commercial [Member] | Other commercial and industrial [Member] | Payment Stream [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0
Accruing [Member] | Commercial [Member] | Other commercial and industrial [Member] | Combination & Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0
Accruing [Member] | Commercial Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0
Troubled Debt Restructurings, Recorded Balance With Payment Default	0	0
Accruing [Member] | Commercial Real Estate [Member] | Payment Stream [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0
Accruing [Member] | Commercial Real Estate [Member] | Combination & Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0
Accruing [Member] | Commercial Real Estate [Member] | Residential construction and land development [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0
Troubled Debt Restructurings, Recorded Balance With Payment Default	0	0
Accruing [Member] | Commercial Real Estate [Member] | Residential construction and land development [Member] | Payment Stream [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0
Accruing [Member] | Commercial Real Estate [Member] | Residential construction and land development [Member] | Combination & Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0
Accruing [Member] | Commercial Real Estate [Member] | Retail [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0
Troubled Debt Restructurings, Recorded Balance With Payment Default	0	0
Accruing [Member] | Commercial Real Estate [Member] | Retail [Member] | Payment Stream [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0
Accruing [Member] | Commercial Real Estate [Member] | Retail [Member] | Combination & Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0
Accruing [Member] | Commercial Real Estate [Member] | Office [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0
Troubled Debt Restructurings, Recorded Balance With Payment Default	0	0
Accruing [Member] | Commercial Real Estate [Member] | Office [Member] | Payment Stream [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0
Accruing [Member] | Commercial Real Estate [Member] | Office [Member] | Combination & Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0
Accruing [Member] | Commercial Real Estate [Member] | Multifamily [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0
Troubled Debt Restructurings, Recorded Balance With Payment Default	0	0
Accruing [Member] | Commercial Real Estate [Member] | Multifamily [Member] | Payment Stream [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0
Accruing [Member] | Commercial Real Estate [Member] | Multifamily [Member] | Combination & Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0
Accruing [Member] | Commercial Real Estate [Member] | Industrial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0
Troubled Debt Restructurings, Recorded Balance With Payment Default	0	0
Accruing [Member] | Commercial Real Estate [Member] | Industrial [Member] | Payment Stream [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0
Accruing [Member] | Commercial Real Estate [Member] | Industrial [Member] | Combination & Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0
Accruing [Member] | Commercial Real Estate [Member] | Other commercial real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0
Troubled Debt Restructurings, Recorded Balance With Payment Default	0	0
Accruing [Member] | Commercial Real Estate [Member] | Other commercial real estate [Member] | Payment Stream [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0
Accruing [Member] | Commercial Real Estate [Member] | Other commercial real estate [Member] | Combination & Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0
Accruing [Member] | Residential Mortgage [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	21,921	28,101
Troubled Debt Restructurings, Recorded Balance With Payment Default	17,154	27,223
Accruing [Member] | Residential Mortgage [Member] | Payment Stream [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	11,879	17,717
Accruing [Member] | Residential Mortgage [Member] | Combination & Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	10,042	10,384
Accruing [Member] | Residential Mortgage [Member] | Permanent mortgage [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0
Troubled Debt Restructurings, Recorded Balance With Payment Default	0	0
Accruing [Member] | Residential Mortgage [Member] | Permanent mortgage [Member] | Payment Stream [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0
Accruing [Member] | Residential Mortgage [Member] | Permanent mortgage [Member] | Combination & Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0
Accruing [Member] | Residential Mortgage [Member] | Permanent mortgages guaranteed by U.S. government agencies [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	21,921	28,101
Troubled Debt Restructurings, Recorded Balance With Payment Default	17,154	27,223
Accruing [Member] | Residential Mortgage [Member] | Permanent mortgages guaranteed by U.S. government agencies [Member] | Payment Stream [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	11,879	17,717
Accruing [Member] | Residential Mortgage [Member] | Permanent mortgages guaranteed by U.S. government agencies [Member] | Combination & Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	10,042	10,384
Accruing [Member] | Residential Mortgage [Member] | Home equity [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0
Troubled Debt Restructurings, Recorded Balance With Payment Default	0	0
Accruing [Member] | Residential Mortgage [Member] | Home equity [Member] | Payment Stream [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0
Accruing [Member] | Residential Mortgage [Member] | Home equity [Member] | Combination & Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0
Accruing [Member] | Personal [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0
Troubled Debt Restructurings, Recorded Balance With Payment Default	0	0
Accruing [Member] | Personal [Member] | Payment Stream [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0
Accruing [Member] | Personal [Member] | Combination & Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0
Nonaccrual [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	30,538	20,319
Troubled Debt Restructurings, Recorded Balance With Payment Default	10,374	7,039
Nonaccrual [Member] | Interest Rate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	730
Nonaccrual [Member] | Payment Stream [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	1,082	4,778
Nonaccrual [Member] | Combination & Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	29,456	14,811
Nonaccrual [Member] | Commercial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	25,995	10,611
Troubled Debt Restructurings, Recorded Balance With Payment Default	8,593	38
Nonaccrual [Member] | Commercial [Member] | Interest Rate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	673
Nonaccrual [Member] | Commercial [Member] | Payment Stream [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0
Nonaccrual [Member] | Commercial [Member] | Combination & Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	25,995	9,938
Nonaccrual [Member] | Commercial [Member] | Energy [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	16,892	2,304
Troubled Debt Restructurings, Recorded Balance With Payment Default	8,593	0
Nonaccrual [Member] | Commercial [Member] | Energy [Member] | Interest Rate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0
Nonaccrual [Member] | Commercial [Member] | Energy [Member] | Payment Stream [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0
Nonaccrual [Member] | Commercial [Member] | Energy [Member] | Combination & Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	16,892	2,304
Nonaccrual [Member] | Commercial [Member] | Services [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	7,577
Troubled Debt Restructurings, Recorded Balance With Payment Default	0	0
Nonaccrual [Member] | Commercial [Member] | Services [Member] | Interest Rate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0
Nonaccrual [Member] | Commercial [Member] | Services [Member] | Payment Stream [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0
Nonaccrual [Member] | Commercial [Member] | Services [Member] | Combination & Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	7,577
Nonaccrual [Member] | Commercial [Member] | Wholesale/retail [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	9,103	0
Troubled Debt Restructurings, Recorded Balance With Payment Default	0	0
Nonaccrual [Member] | Commercial [Member] | Wholesale/retail [Member] | Interest Rate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0
Nonaccrual [Member] | Commercial [Member] | Wholesale/retail [Member] | Payment Stream [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0
Nonaccrual [Member] | Commercial [Member] | Wholesale/retail [Member] | Combination & Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	9,103	0
Nonaccrual [Member] | Commercial [Member] | Manufacturing [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0
Troubled Debt Restructurings, Recorded Balance With Payment Default	0	0
Nonaccrual [Member] | Commercial [Member] | Manufacturing [Member] | Interest Rate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0
Nonaccrual [Member] | Commercial [Member] | Manufacturing [Member] | Payment Stream [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0
Nonaccrual [Member] | Commercial [Member] | Manufacturing [Member] | Combination & Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0
Nonaccrual [Member] | Commercial [Member] | Healthcare [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	673
Troubled Debt Restructurings, Recorded Balance With Payment Default	0	0
Nonaccrual [Member] | Commercial [Member] | Healthcare [Member] | Interest Rate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	673
Nonaccrual [Member] | Commercial [Member] | Healthcare [Member] | Payment Stream [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0
Nonaccrual [Member] | Commercial [Member] | Healthcare [Member] | Combination & Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0
Nonaccrual [Member] | Commercial [Member] | Other commercial and industrial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	57
Troubled Debt Restructurings, Recorded Balance With Payment Default	0	38
Nonaccrual [Member] | Commercial [Member] | Other commercial and industrial [Member] | Interest Rate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0
Nonaccrual [Member] | Commercial [Member] | Other commercial and industrial [Member] | Payment Stream [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0
Nonaccrual [Member] | Commercial [Member] | Other commercial and industrial [Member] | Combination & Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	57
Nonaccrual [Member] | Commercial Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	329
Troubled Debt Restructurings, Recorded Balance With Payment Default	0	329
Nonaccrual [Member] | Commercial Real Estate [Member] | Interest Rate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0
Nonaccrual [Member] | Commercial Real Estate [Member] | Payment Stream [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	329
Nonaccrual [Member] | Commercial Real Estate [Member] | Combination & Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0
Nonaccrual [Member] | Commercial Real Estate [Member] | Residential construction and land development [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	329
Troubled Debt Restructurings, Recorded Balance With Payment Default	0	329
Nonaccrual [Member] | Commercial Real Estate [Member] | Residential construction and land development [Member] | Interest Rate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0
Nonaccrual [Member] | Commercial Real Estate [Member] | Residential construction and land development [Member] | Payment Stream [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	329
Nonaccrual [Member] | Commercial Real Estate [Member] | Residential construction and land development [Member] | Combination & Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0
Nonaccrual [Member] | Commercial Real Estate [Member] | Retail [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0
Troubled Debt Restructurings, Recorded Balance With Payment Default	0	0
Nonaccrual [Member] | Commercial Real Estate [Member] | Retail [Member] | Interest Rate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0
Nonaccrual [Member] | Commercial Real Estate [Member] | Retail [Member] | Payment Stream [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0
Nonaccrual [Member] | Commercial Real Estate [Member] | Retail [Member] | Combination & Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0
Nonaccrual [Member] | Commercial Real Estate [Member] | Office [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0
Troubled Debt Restructurings, Recorded Balance With Payment Default	0	0
Nonaccrual [Member] | Commercial Real Estate [Member] | Office [Member] | Interest Rate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0
Nonaccrual [Member] | Commercial Real Estate [Member] | Office [Member] | Payment Stream [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0
Nonaccrual [Member] | Commercial Real Estate [Member] | Office [Member] | Combination & Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0
Nonaccrual [Member] | Commercial Real Estate [Member] | Multifamily [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0
Troubled Debt Restructurings, Recorded Balance With Payment Default	0	0
Nonaccrual [Member] | Commercial Real Estate [Member] | Multifamily [Member] | Interest Rate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0
Nonaccrual [Member] | Commercial Real Estate [Member] | Multifamily [Member] | Payment Stream [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0
Nonaccrual [Member] | Commercial Real Estate [Member] | Multifamily [Member] | Combination & Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0
Nonaccrual [Member] | Commercial Real Estate [Member] | Industrial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0
Troubled Debt Restructurings, Recorded Balance With Payment Default	0	0
Nonaccrual [Member] | Commercial Real Estate [Member] | Industrial [Member] | Interest Rate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0
Nonaccrual [Member] | Commercial Real Estate [Member] | Industrial [Member] | Payment Stream [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0
Nonaccrual [Member] | Commercial Real Estate [Member] | Industrial [Member] | Combination & Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0
Nonaccrual [Member] | Commercial Real Estate [Member] | Other commercial real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0
Troubled Debt Restructurings, Recorded Balance With Payment Default	0	0
Nonaccrual [Member] | Commercial Real Estate [Member] | Other commercial real estate [Member] | Interest Rate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0
Nonaccrual [Member] | Commercial Real Estate [Member] | Other commercial real estate [Member] | Payment Stream [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0
Nonaccrual [Member] | Commercial Real Estate [Member] | Other commercial real estate [Member] | Combination & Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0
Nonaccrual [Member] | Residential Mortgage [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	4,466	9,264
Troubled Debt Restructurings, Recorded Balance With Payment Default	1,776	6,659
Nonaccrual [Member] | Residential Mortgage [Member] | Interest Rate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	57
Nonaccrual [Member] | Residential Mortgage [Member] | Payment Stream [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	1,082	4,449
Nonaccrual [Member] | Residential Mortgage [Member] | Combination & Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	3,384	4,758
Nonaccrual [Member] | Residential Mortgage [Member] | Permanent mortgage [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	1,364	4,055
Troubled Debt Restructurings, Recorded Balance With Payment Default	544	3,034
Nonaccrual [Member] | Residential Mortgage [Member] | Permanent mortgage [Member] | Interest Rate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0
Nonaccrual [Member] | Residential Mortgage [Member] | Permanent mortgage [Member] | Payment Stream [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	1,036	3,004
Nonaccrual [Member] | Residential Mortgage [Member] | Permanent mortgage [Member] | Combination & Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	328	1,051
Nonaccrual [Member] | Residential Mortgage [Member] | Permanent mortgages guaranteed by U.S. government agencies [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	979	3,101
Troubled Debt Restructurings, Recorded Balance With Payment Default	647	3,101
Nonaccrual [Member] | Residential Mortgage [Member] | Permanent mortgages guaranteed by U.S. government agencies [Member] | Interest Rate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0
Nonaccrual [Member] | Residential Mortgage [Member] | Permanent mortgages guaranteed by U.S. government agencies [Member] | Payment Stream [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	1,264
Nonaccrual [Member] | Residential Mortgage [Member] | Permanent mortgages guaranteed by U.S. government agencies [Member] | Combination & Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	979	1,837
Nonaccrual [Member] | Residential Mortgage [Member] | Home equity [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	2,123	2,108
Troubled Debt Restructurings, Recorded Balance With Payment Default	585	524
Nonaccrual [Member] | Residential Mortgage [Member] | Home equity [Member] | Interest Rate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	57
Nonaccrual [Member] | Residential Mortgage [Member] | Home equity [Member] | Payment Stream [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	46	181
Nonaccrual [Member] | Residential Mortgage [Member] | Home equity [Member] | Combination & Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	2,077	1,870
Nonaccrual [Member] | Personal [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	77	115
Troubled Debt Restructurings, Recorded Balance With Payment Default	5	13
Nonaccrual [Member] | Personal [Member] | Interest Rate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0
Nonaccrual [Member] | Personal [Member] | Payment Stream [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0
Nonaccrual [Member] | Personal [Member] | Combination & Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	$ 77	$ 115

Loans and Allowances for Cred69

Loans and Allowances for Credit Losses, By Aging Category (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Financing receivable, recorded investment, aging [Abstract]
Current	$ 16,597,641	$ 15,626,933
Nonaccrual	230,984	147,128
Total	16,989,660	15,941,154
Commercial [Member]
Financing receivable, recorded investment, aging [Abstract]
Current	10,205,838	10,165,995
Nonaccrual	178,953	76,424
Total	10,390,824	10,252,531
Commercial [Member] | Energy [Member]
Financing receivable, recorded investment, aging [Abstract]
Current	2,364,890	3,033,504
Nonaccrual	132,499	61,189
Total	2,497,868	3,097,328
Commercial [Member] | Services [Member]
Financing receivable, recorded investment, aging [Abstract]
Current	3,099,605	2,769,895
Nonaccrual	8,173	10,290
Total	3,108,990	2,784,276
Commercial [Member] | Wholesale/retail [Member]
Financing receivable, recorded investment, aging [Abstract]
Current	1,561,650	1,418,396
Nonaccrual	11,407	2,919
Total	1,576,818	1,422,064
Commercial [Member] | Manufacturing [Member]
Financing receivable, recorded investment, aging [Abstract]
Current	509,662	556,398
Nonaccrual	4,931	331
Total	514,975	556,729
Commercial [Member] | Healthcare [Member]
Financing receivable, recorded investment, aging [Abstract]
Current	2,201,050	1,879,873
Nonaccrual	825	1,072
Total	2,201,916	1,883,380
Commercial [Member] | Other commercial and industrial [Member]
Financing receivable, recorded investment, aging [Abstract]
Current	468,981	507,929
Nonaccrual	21,118	623
Total	490,257	508,754
Commercial Real Estate [Member]
Financing receivable, recorded investment, aging [Abstract]
Current	3,803,519	3,241,541
Nonaccrual	5,521	9,001
Total	3,809,046	3,259,033
Commercial Real Estate [Member] | Residential construction and land development [Member]
Financing receivable, recorded investment, aging [Abstract]
Current	132,100	156,017
Nonaccrual	3,433	4,409
Total	135,533	160,426
Commercial Real Estate [Member] | Retail [Member]
Financing receivable, recorded investment, aging [Abstract]
Current	761,562	795,180
Nonaccrual	326	1,319
Total	761,888	796,499
Commercial Real Estate [Member] | Office [Member]
Financing receivable, recorded investment, aging [Abstract]
Current	798,462	637,056
Nonaccrual	426	651
Total	798,888	637,707
Commercial Real Estate [Member] | Multifamily [Member]
Financing receivable, recorded investment, aging [Abstract]
Current	903,234	742,697
Nonaccrual	38	274
Total	903,272	751,085
Commercial Real Estate [Member] | Industrial [Member]
Financing receivable, recorded investment, aging [Abstract]
Current	871,673	563,093
Nonaccrual	76	76
Total	871,749	563,169
Commercial Real Estate [Member] | Other commercial real estate [Member]
Financing receivable, recorded investment, aging [Abstract]
Current	336,488	347,498
Nonaccrual	1,222	2,272
Total	337,716	350,147
Residential Mortgage [Member]
Financing receivable, recorded investment, aging [Abstract]
Current	1,749,473	1,667,864
Nonaccrual	46,220	61,240
Total	1,949,832	1,876,893
Residential Mortgage [Member] | Permanent mortgage [Member]
Financing receivable, recorded investment, aging [Abstract]
Current	979,386	913,062
Nonaccrual	22,855	28,984
Total	1,006,820	945,336
Residential Mortgage [Member] | Permanent mortgages guaranteed by U.S. government agencies [Member]
Financing receivable, recorded investment, aging [Abstract]
Current	40,594	33,653
Nonaccrual	11,846	21,900
Total	199,387	196,937
Residential Mortgage [Member] | Home equity [Member]
Financing receivable, recorded investment, aging [Abstract]
Current	729,493	721,149
Nonaccrual	11,519	10,356
Total	743,625	734,620
Personal [Member]
Financing receivable, recorded investment, aging [Abstract]
Current	838,811	551,533
Nonaccrual	290	463
Total	839,958	552,697
30 to 59 Days Past Due [Member]
Financing receivable, recorded investment, aging [Abstract]
Past Due	28,603	36,703
30 to 59 Days Past Due [Member] | Commercial [Member]
Financing receivable, recorded investment, aging [Abstract]
Past Due	4,968	5,269
30 to 59 Days Past Due [Member] | Commercial [Member] | Energy [Member]
Financing receivable, recorded investment, aging [Abstract]
Past Due	479	2,635
30 to 59 Days Past Due [Member] | Commercial [Member] | Services [Member]
Financing receivable, recorded investment, aging [Abstract]
Past Due	191	66
30 to 59 Days Past Due [Member] | Commercial [Member] | Wholesale/retail [Member]
Financing receivable, recorded investment, aging [Abstract]
Past Due	3,761	49
30 to 59 Days Past Due [Member] | Commercial [Member] | Manufacturing [Member]
Financing receivable, recorded investment, aging [Abstract]
Past Due	382	0
30 to 59 Days Past Due [Member] | Commercial [Member] | Healthcare [Member]
Financing receivable, recorded investment, aging [Abstract]
Past Due	0	2,435
30 to 59 Days Past Due [Member] | Commercial [Member] | Other commercial and industrial [Member]
Financing receivable, recorded investment, aging [Abstract]
Past Due	155	84
30 to 59 Days Past Due [Member] | Commercial Real Estate [Member]
Financing receivable, recorded investment, aging [Abstract]
Past Due	6	8,114
30 to 59 Days Past Due [Member] | Commercial Real Estate [Member] | Residential construction and land development [Member]
Financing receivable, recorded investment, aging [Abstract]
Past Due	0	0
30 to 59 Days Past Due [Member] | Commercial Real Estate [Member] | Retail [Member]
Financing receivable, recorded investment, aging [Abstract]
Past Due	0	0
30 to 59 Days Past Due [Member] | Commercial Real Estate [Member] | Office [Member]
Financing receivable, recorded investment, aging [Abstract]
Past Due	0	0
30 to 59 Days Past Due [Member] | Commercial Real Estate [Member] | Multifamily [Member]
Financing receivable, recorded investment, aging [Abstract]
Past Due	0	8,114
30 to 59 Days Past Due [Member] | Commercial Real Estate [Member] | Industrial [Member]
Financing receivable, recorded investment, aging [Abstract]
Past Due	0	0
30 to 59 Days Past Due [Member] | Commercial Real Estate [Member] | Other commercial real estate [Member]
Financing receivable, recorded investment, aging [Abstract]
Past Due	6	0
30 to 59 Days Past Due [Member] | Residential Mortgage [Member]
Financing receivable, recorded investment, aging [Abstract]
Past Due	23,040	22,655
30 to 59 Days Past Due [Member] | Residential Mortgage [Member] | Permanent mortgage [Member]
Financing receivable, recorded investment, aging [Abstract]
Past Due	3,299	3,290
30 to 59 Days Past Due [Member] | Residential Mortgage [Member] | Permanent mortgages guaranteed by U.S. government agencies [Member]
Financing receivable, recorded investment, aging [Abstract]
Past Due	17,465	16,986
30 to 59 Days Past Due [Member] | Residential Mortgage [Member] | Home equity [Member]
Financing receivable, recorded investment, aging [Abstract]
Past Due	2,276	2,379
30 to 59 Days Past Due [Member] | Personal [Member]
Financing receivable, recorded investment, aging [Abstract]
Past Due	589	665
60 to 89 Days Past Due [Member]
Financing receivable, recorded investment, aging [Abstract]
Past Due	16,748	18,182
60 to 89 Days Past Due [Member] | Commercial [Member]
Financing receivable, recorded investment, aging [Abstract]
Past Due	1,065	4,041
60 to 89 Days Past Due [Member] | Commercial [Member] | Energy [Member]
Financing receivable, recorded investment, aging [Abstract]
Past Due	0	0
60 to 89 Days Past Due [Member] | Commercial [Member] | Services [Member]
Financing receivable, recorded investment, aging [Abstract]
Past Due	1,021	4,025
60 to 89 Days Past Due [Member] | Commercial [Member] | Wholesale/retail [Member]
Financing receivable, recorded investment, aging [Abstract]
Past Due	0	0
60 to 89 Days Past Due [Member] | Commercial [Member] | Manufacturing [Member]
Financing receivable, recorded investment, aging [Abstract]
Past Due	0	0
60 to 89 Days Past Due [Member] | Commercial [Member] | Healthcare [Member]
Financing receivable, recorded investment, aging [Abstract]
Past Due	41	0
60 to 89 Days Past Due [Member] | Commercial [Member] | Other commercial and industrial [Member]
Financing receivable, recorded investment, aging [Abstract]
Past Due	3	16
60 to 89 Days Past Due [Member] | Commercial Real Estate [Member]
Financing receivable, recorded investment, aging [Abstract]
Past Due	0	0
60 to 89 Days Past Due [Member] | Commercial Real Estate [Member] | Residential construction and land development [Member]
Financing receivable, recorded investment, aging [Abstract]
Past Due	0	0
60 to 89 Days Past Due [Member] | Commercial Real Estate [Member] | Retail [Member]
Financing receivable, recorded investment, aging [Abstract]
Past Due	0	0
60 to 89 Days Past Due [Member] | Commercial Real Estate [Member] | Office [Member]
Financing receivable, recorded investment, aging [Abstract]
Past Due	0	0
60 to 89 Days Past Due [Member] | Commercial Real Estate [Member] | Multifamily [Member]
Financing receivable, recorded investment, aging [Abstract]
Past Due	0	0
60 to 89 Days Past Due [Member] | Commercial Real Estate [Member] | Industrial [Member]
Financing receivable, recorded investment, aging [Abstract]
Past Due	0	0
60 to 89 Days Past Due [Member] | Commercial Real Estate [Member] | Other commercial real estate [Member]
Financing receivable, recorded investment, aging [Abstract]
Past Due	0	0
60 to 89 Days Past Due [Member] | Residential Mortgage [Member]
Financing receivable, recorded investment, aging [Abstract]
Past Due	15,420	14,113
60 to 89 Days Past Due [Member] | Residential Mortgage [Member] | Permanent mortgage [Member]
Financing receivable, recorded investment, aging [Abstract]
Past Due	1,280	0
60 to 89 Days Past Due [Member] | Residential Mortgage [Member] | Permanent mortgages guaranteed by U.S. government agencies [Member]
Financing receivable, recorded investment, aging [Abstract]
Past Due	13,803	13,397
60 to 89 Days Past Due [Member] | Residential Mortgage [Member] | Home equity [Member]
Financing receivable, recorded investment, aging [Abstract]
Past Due	337	716
60 to 89 Days Past Due [Member] | Personal [Member]
Financing receivable, recorded investment, aging [Abstract]
Past Due	263	28
90 Days or More [Member]
Financing receivable, recorded investment, aging [Abstract]
Past Due	115,684	112,208
90 Days or More [Member] | Commercial [Member]
Financing receivable, recorded investment, aging [Abstract]
Past Due	0	802
90 Days or More [Member] | Commercial [Member] | Energy [Member]
Financing receivable, recorded investment, aging [Abstract]
Past Due	0	0
90 Days or More [Member] | Commercial [Member] | Services [Member]
Financing receivable, recorded investment, aging [Abstract]
Past Due	0	0
90 Days or More [Member] | Commercial [Member] | Wholesale/retail [Member]
Financing receivable, recorded investment, aging [Abstract]
Past Due	0	700
90 Days or More [Member] | Commercial [Member] | Manufacturing [Member]
Financing receivable, recorded investment, aging [Abstract]
Past Due	0	0
90 Days or More [Member] | Commercial [Member] | Healthcare [Member]
Financing receivable, recorded investment, aging [Abstract]
Past Due	0	0
90 Days or More [Member] | Commercial [Member] | Other commercial and industrial [Member]
Financing receivable, recorded investment, aging [Abstract]
Past Due	0	102
90 Days or More [Member] | Commercial Real Estate [Member]
Financing receivable, recorded investment, aging [Abstract]
Past Due	0	377
90 Days or More [Member] | Commercial Real Estate [Member] | Residential construction and land development [Member]
Financing receivable, recorded investment, aging [Abstract]
Past Due	0	0
90 Days or More [Member] | Commercial Real Estate [Member] | Retail [Member]
Financing receivable, recorded investment, aging [Abstract]
Past Due	0	0
90 Days or More [Member] | Commercial Real Estate [Member] | Office [Member]
Financing receivable, recorded investment, aging [Abstract]
Past Due	0	0
90 Days or More [Member] | Commercial Real Estate [Member] | Multifamily [Member]
Financing receivable, recorded investment, aging [Abstract]
Past Due	0	0
90 Days or More [Member] | Commercial Real Estate [Member] | Industrial [Member]
Financing receivable, recorded investment, aging [Abstract]
Past Due	0	0
90 Days or More [Member] | Commercial Real Estate [Member] | Other commercial real estate [Member]
Financing receivable, recorded investment, aging [Abstract]
Past Due	0	377
90 Days or More [Member] | Residential Mortgage [Member]
Financing receivable, recorded investment, aging [Abstract]
Past Due	115,679	111,021
90 Days or More [Member] | Residential Mortgage [Member] | Permanent mortgage [Member]
Financing receivable, recorded investment, aging [Abstract]
Past Due	0	0
90 Days or More [Member] | Residential Mortgage [Member] | Permanent mortgages guaranteed by U.S. government agencies [Member]
Financing receivable, recorded investment, aging [Abstract]
Past Due	115,679	111,001
90 Days or More [Member] | Residential Mortgage [Member] | Home equity [Member]
Financing receivable, recorded investment, aging [Abstract]
Past Due	0	20
90 Days or More [Member] | Personal [Member]
Financing receivable, recorded investment, aging [Abstract]
Past Due	$ 5	$ 8

Premises and Equipment Premis70

Premises and Equipment Premises and Equipment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Premises and Equipment [Line Items]
Premises and equipment	$ 733,160	$ 674,870
Less accumulated depreciation	407,311	368,380
Premises and equipment, net of accumulated depreciation	325,849	306,490
Depreciation Expense	40,000	34,000	$ 33,000
Land
Premises and Equipment [Line Items]
Premises and equipment	70,552	72,612
Buildings and improvements
Premises and Equipment [Line Items]
Premises and equipment	250,311	225,181
Software
Premises and Equipment [Line Items]
Premises and equipment	158,155	142,476
Furniture and equipment
Premises and Equipment [Line Items]
Premises and equipment	217,399	194,715
Construction in progress
Premises and Equipment [Line Items]
Premises and equipment	$ 36,743	$ 39,886

Goodwill and Intangible Asset71

Goodwill and Intangible Assets Acquisitions (Details) - USD ($) $ in Thousands		Dec. 01, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities [Abstract]
Goodwill			$ 448,899	$ 385,461	$ 377,780
Series of Individually Immaterial Business Acquisitions [Member]
Business Acquisition [Line Items]
Assets Under Management at time of acquisition			340,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets [Abstract]
Intangible assets			5,300	11,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities [Abstract]
Purchase Price			7,700	18,000
Goodwill			$ 3,300	$ 2,700
MBT Bancshares [Member]
Business Acquisition [Line Items]
Effective Date of Acquisition		Dec. 1, 2016
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets [Abstract]
Cash and cash equivalents		$ 166,215
Securities		14,431
Loans	[1]	444,482
Premises and equipments, net		8,035
Intangible assets		6,510
Other assets		3,599
Total assets acquired		643,272
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities [Abstract]
Deposits		598,735
Other borrowings		7,217
Other liabilities		980
Total liabilities assumed		606,932
Net assets acquired		36,340
Purchase Price		102,500
Goodwill		$ 66,160
[1]	Loans are presented net of participations sold to BOKF NA.

Goodwill and Intangible Asset72

Goodwill and Intangible Assets (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, net		$ 46,931	$ 43,909
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
2,017		5,373
2,018		4,640
2,019		4,272
2,020		4,117
2,021		3,738
Thereafter		24,791
Goodwill [Roll Forward]
Goodwill, Gross Beginning Balance		385,689	378,008
Goodwill, Accumulated Impairment Beginning Balance		(228)	(228)
Goodwill, Net Beginning Balance		385,461	377,780
Goodwill acquired during period		69,496	7,681
Adjustment	[1]	(6,058)
Goodwill, Gross Ending Balance		449,127	385,689
Goodwill, Accumulated Impairment Ending Balance		(228)	(228)
Goodwill, Net Ending Balance		448,899	385,461
Commercial [Member]
Goodwill [Roll Forward]
Goodwill, Gross Beginning Balance		277,044	269,363
Goodwill, Accumulated Impairment Beginning Balance		0	0
Goodwill, Net Beginning Balance		277,044	269,363
Goodwill acquired during period		1,210	7,681
Adjustment	[1]	(6,058)
Goodwill, Gross Ending Balance		272,196	277,044
Goodwill, Accumulated Impairment Ending Balance		0	0
Goodwill, Net Ending Balance		272,196	277,044
Consumer [Member]
Goodwill [Roll Forward]
Goodwill, Gross Beginning Balance		39,251	39,251
Goodwill, Accumulated Impairment Beginning Balance		(228)	(228)
Goodwill, Net Beginning Balance		39,023	39,023
Goodwill acquired during period		0	0
Adjustment	[1]	0
Goodwill, Gross Ending Balance		39,251	39,251
Goodwill, Accumulated Impairment Ending Balance		(228)	(228)
Goodwill, Net Ending Balance		39,023	39,023
Wealth Management [Member]
Goodwill [Roll Forward]
Goodwill, Gross Beginning Balance		69,394	69,394
Goodwill, Accumulated Impairment Beginning Balance		0	0
Goodwill, Net Beginning Balance		69,394	69,394
Goodwill acquired during period		2,126	0
Adjustment	[1]	0
Goodwill, Gross Ending Balance		71,520	69,394
Goodwill, Accumulated Impairment Ending Balance		0	0
Goodwill, Net Ending Balance		71,520	69,394
Funds Management and Other [Member]
Goodwill [Roll Forward]
Goodwill, Gross Beginning Balance		0	0
Goodwill, Accumulated Impairment Beginning Balance		0	0
Goodwill, Net Beginning Balance		0	0
Goodwill acquired during period		66,160	0
Adjustment	[1]	0
Goodwill, Gross Ending Balance		66,160	0
Goodwill, Accumulated Impairment Ending Balance		0	0
Goodwill, Net Ending Balance		66,160	0
Core deposits premiums [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, gross		35,879	29,369
Accumulated amortization		29,369	29,101
Finite-lived intangible assets, net		6,510	268
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
2,017		808
2,018		732
2,019		716
2,020		697
2,021		675
Thereafter		2,882
Other identifiable intangible assets [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, gross		60,951	55,509
Accumulated amortization		20,530	11,868
Finite-lived intangible assets, net		40,421	$ 43,641
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
2,017		4,565
2,018		3,908
2,019		3,556
2,020		3,420
2,021		3,063
Thereafter		$ 21,909
[1]	Completion of an external audit of Heartland Food Products resulted in a reallocation of the purchase price between net assets acquired, intangible assets and goodwill during 2016.

Mortgage Banking Activities, Co

Mortgage Banking Activities, Components of Loans Held For Sale (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Schedule of Residential Mortgage Loans Held For Sale [Line Items]
Number of days for past due for a residential mortgage loan to be considered nonperforming (in days)	90 days	90 days
Residential mortgage loans held for sale, nonperforming	$ 0	$ 0
Credit losses recognized on residential mortgage loans held for sale	0	0
Components of Residential Mortgage Loans Held for Sale [Abstract]
Unpaid principal balance	286,414	293,637
Residential mortgage loans held for sale, Fair value	286,971	299,505
Total residential mortgages loans held for sale and mortgage loan commitments, net of forward sales contracts	$ 301,897	$ 308,439
Not Designated as Hedging Instrument [Member] | Residential mortgage loan commitments [Member]
Schedule of Residential Mortgage Loans Held For Sale [Line Items]
General number of days outstanding for residential mortgage commitments, minimum (in days)	60 days	60 days
General number of days outstanding for residential mortgage commitments, maximum (in days)	90 days	90 days
Components of Residential Mortgage Loans Held for Sale [Abstract]
Notional	$ 318,359	$ 601,147
Derivative, Net fair value	$ 9,733	$ 8,134
Not Designated as Hedging Instrument [Member] | Forward sales contracts [Member]
Schedule of Residential Mortgage Loans Held For Sale [Line Items]
General number of days for delivery of loans, for which the price is set by forward sales contracts, minimum (in days)	60 days	60 days
General number of days for delivery of loans, for which the price is set by forward sales contracts, maximum (in days)	90 days	90 days
Components of Residential Mortgage Loans Held for Sale [Abstract]
Notional	$ 569,543	$ 884,710
Derivative, Net fair value	$ 5,193	$ 800

Mortgage Banking Activities, Mo

Mortgage Banking Activities, Mortgage Banking Revenue (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Mortgage Banking Revenue [Abstract]
Gain (Loss) on Sale of Mortgage Loans	$ 68,947	$ 67,407	$ 56,696
Net change in unrealized gain on mortgage loans held for sale	(5,311)	(784)	5,357
Change in fair value of mortgage loan commitments	1,599	(1,837)	7,315
Change in the fair value of forward sales commitments	4,393	4,801	(8,307)
Mortgage Production Revenue	69,628	69,587	61,061
Bank Servicing Fees	64,286	56,415	48,032
Mortgage banking revenue	$ 133,914	$ 126,002	$ 109,093

Mortgage Banking Activities, 75

Mortgage Banking Activities, Mortgage Servicing Rights (Details)	12 Months Ended
	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)
Summary of Mortgage Servicing Rights [Abstract]
Number of residential mortgage loans serviced	139,340	131,859	117,483
Outstanding principal balance of residential mortgage loans serviced for others	$ 21,997,568,000	$ 19,678,226,000	$ 16,162,887,000
Weighted average interest rate (in hundredths)	3.97%	4.12%	4.29%
Remaining contractual term (in months)	301 months	300 months	296 months
Servicing Asset at Fair Value, Amount [Roll Forward]
Beginning balance	$ 218,605,000	$ 171,976,000	$ 153,333,000
Additions, net	71,405,000	79,546,000	54,413,000
Change in fair value due to loan runoff	(40,744,000)	(28,064,000)	(19,325,000)
Change in fair value due to market changes	(2,193,000)	(4,853,000)	(16,445,000)
Ending balance	$ 247,073,000	$ 218,605,000	171,976,000
Servicing Assets at Fair Value, Assumptions Used to Estimate Fair Value [Abstract]
Discount rate - risk-free rate plus a market premium (in hundredths)	10.08%	10.11%
Prepayment rate - based upon loan interest rate, original term and loan type, Minimum	8.98%	7.41%
Prepayment rate - based upon loan interest rate, original term and loan type, Maximum	16.91%	23.88%
Loan servicing costs - annually per loan based upon loan type, Performing, minimum (in dollars per loan)	$ 63	$ 63
Loan servicing costs - annually per loan based upon loan type, Performing, maximum (in dollars per loan)	120	105
Loan servicing costs - annually per loan based upon loan type, Delinquent loans, Minimum (in dollars per loan)	150	150
Loan servicing costs - annually per loan based upon loan type, Delinquent loans, Maximum (in dollars per loan)	500	500
Loan servicing costs - annually per loan based upon loan type, Loans in foreclosure, Minimum (in dollars per loan)	650	650
Loan servicing costs - annually per loan based upon loan type, Loans in foreclosure, Maximum (in dollars per loan)	$ 4,250	$ 4,250
Primary secondary mortgage rate spread	105	130
Escrow earnings rate - indexed to rates paid on deposit accounts with comparable average life (in hundredths)	1.98%	1.73%
Interest Rate Sensitivity of Mortgage Servicing Rights [Abstract]
Economic hedge threshold for interest rate sensitivity for mortgage servicing rights and securities held (in basis points)	50
Dollar increase in fair value of mortgage servicing rights due to 50 basis point increase in mortgage interest rates	$ 25,000,000
Dollar decrease in fair value of mortgage servicing rights due to 50 basis point decrease in mortgage interest rates	29,000,000
Purchased [Member]
Servicing Asset at Fair Value, Amount [Roll Forward]
Beginning balance	9,911,000	$ 11,114,000	15,935,000
Additions, net	0	0	0
Change in fair value due to loan runoff	(2,844,000)	(2,645,000)	(2,357,000)
Change in fair value due to market changes	1,842,000	1,442,000	(2,464,000)
Ending balance	8,909,000	9,911,000	11,114,000
Originated [Member]
Servicing Asset at Fair Value, Amount [Roll Forward]
Beginning balance	208,694,000	160,862,000	137,398,000
Additions, net	71,405,000	79,546,000	54,413,000
Change in fair value due to loan runoff	(37,900,000)	(25,419,000)	(16,968,000)
Change in fair value due to market changes	(4,035,000)	(6,295,000)	(13,981,000)
Ending balance	$ 238,164,000	$ 208,694,000	$ 160,862,000

Mortgage Banking Activities, Lo

Mortgage Banking Activities, Loans Serviced for Others (Details) $ in Thousands	Dec. 31, 2016USD ($)
Financing Receivable, Recorded Investment, Aging [Abstract]
Current	$ 21,568,674
30 To 59 Days Past Due	279,398
60 To 89 Days Past Due	77,930
90 Days or More Past Due	71,566
Total	21,997,568
FHLMC [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Current	7,950,818
30 To 59 Days Past Due	52,434
60 To 89 Days Past Due	9,812
90 Days or More Past Due	25,670
Total	8,038,734
FNMA [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Current	6,922,833
30 To 59 Days Past Due	44,532
60 To 89 Days Past Due	11,233
90 Days or More Past Due	21,486
Total	7,000,084
GNMA [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Current	6,304,914
30 To 59 Days Past Due	181,669
60 To 89 Days Past Due	56,534
90 Days or More Past Due	22,471
Total	6,565,588
Other [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Current	390,109
30 To 59 Days Past Due	763
60 To 89 Days Past Due	351
90 Days or More Past Due	1,939
Total	$ 393,162

Mortgage Banking Activities, 77

Mortgage Banking Activities, Loans Sold With Recourse (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)
Residential mortgage loans sold with recourse [Abstract]
Carrying amount of residential mortgage loans sold and subject to recourse	$ 139,000	$ 155,000
Activity in the allowance for losses on loans sold with recourse [Abstract]
Beginning balance	4,649	7,299	$ 9,562
Provision for recourse losses	725	(982)	354
Loans charged off, net	(1,358)	(1,668)	(2,617)
Ending balance	$ 4,016	$ 4,649	7,299
Residential Mortgage Loans Subject to Repurchase Under Standard Representations and Warranties [Abstract]
Number of mortgages purchased under repurchase agreement with US government sponsored entities	18
Purchase price of loans purchased under repurchase agreement with government sponsored entities	$ 3,900
Number of loans sold under standard representation and warranties indemnified	7
Number of loans with unresolved deficiency requests	233	198
Principal balance of loans with unresolved deficiency requests	$ 17,382	$ 15,624
Unpaid principal balance of mortgage loans subject to indemnification under standard representations and warranties	5,803	4,365
Activity in Accruals for Mortgage Losses [Roll Forward]
Beginning balance	3,359	3,220
Provision for losses	27	353
Charge-offs, net	(598)	(214)
Ending balance	$ 2,788	$ 3,359	$ 3,220

Deposits (Details)

Deposits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Interest expense on deposits [Abstract]
Transaction deposits	$ 13,906	$ 8,821	$ 9,757
Savings	386	383	401
Time Deposit, Interest Expense [Abstract]
Certificates of deposits under $100,000	8,776	11,894	14,278
Certificates of deposits $100,000 and over	10,123	10,643	11,878
Other time deposits	7,303	12,429	14,369
Total time	26,202	34,966	40,525
Total	40,494	44,170	$ 50,683
Time Deposit Information [Abstract]
Time deposits in denomination of $250,000 or more	866,000	905,000
Time Deposit Maturities [Abstract]
2,017	1,300,000
2,018	340,000
2,019	71,000
2,020	94,000
2,021	114,000
Thereafter	342,000
Fixed rate, brokered certificates of deposits	$ 417,000	$ 358,000
Weighted-average interest rate paid on fixed rate, brokered certificates of deposits (in hundredths)	1.33%	1.48%
Other Deposits Information [Abstract]
Overdrawn customer transaction deposits reclassified as loan balances	$ 9,700	$ 5,300

Other Borrowings (Details)

Other Borrowings (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Other Borrowings [Line Items]
Balance		$ 5,717,302	$ 6,277,866	$ 3,726,277
Average Balance		$ 6,901,856	$ 5,880,647	$ 3,699,621
Rate		0.60%	0.36%	0.43%
U.S. government agency mortgage-backed securities [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Amortized Cost		$ 655,529	$ 685,458
Fair Value		655,851	688,485
Repurchase Liability	[1]	$ 668,661	$ 722,444
Average Rate (in hundredths)		0.02%	0.02%
U.S. government agency mortgage-backed securities [Member] | Overnight [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Amortized Cost		$ 655,529	$ 685,458
Fair Value		655,851	688,485
Repurchase Liability	[1]	$ 668,661	$ 722,444
Average Rate (in hundredths)		0.02%	0.02%
U.S. government agency mortgage-backed securities [Member] | Long-term [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Amortized Cost		$ 0	$ 0
Fair Value		0	0
Repurchase Liability	[1]	$ 0	$ 0
Average Rate (in hundredths)		0.00%	0.00%
Parent Company and other non-bank subsidiaries [Member]
Other Borrowings [Line Items]
Balance		$ 152,949	$ 0	$ 0
Average Balance		$ 77,112	0	$ 0
Rate		5.86%		0.00%
Other borrowings, Maturities [Abstract]
2,017		$ 0
2,018		0
2,019		0
2,020		0
2,021		0
Thereafter		152,949
Parent Company and other non-bank subsidiaries [Member] | Other Borrowings [Member]
Other Borrowings [Line Items]
Balance		8,309	0	$ 0
Average Balance		$ 2,684	$ 0	$ 0
Rate		13.19%	0.00%	0.00%
Parent Company and other non-bank subsidiaries [Member] | Trust preferred debt [Member]
Other Borrowings [Line Items]
Balance		$ 7,217	$ 0	$ 0
Rate		3.28%	0.00%	0.00%
Average Balance		$ 611	$ 0	$ 0
Rate		3.27%	0.00%	0.00%
Maximum Outstanding At Any Month End		$ 7,217	$ 0	$ 0
Parent Company and other non-bank subsidiaries [Member] | Trust preferred debt, 2003 issuance [Member]
Other Borrowings [Line Items]
Balance		$ 3,100
Other borrowings, Other Disclosures [Abstract]
Maturity date		Sep. 17, 2033
Interest rate description		three-month LIBOR plus 2.95%
Parent Company and other non-bank subsidiaries [Member] | Trust preferred debt, 2006 issuance [Member]
Other Borrowings [Line Items]
Balance		$ 4,100
Other borrowings, Other Disclosures [Abstract]
Maturity date		Dec. 15, 2036
Interest rate description		three-month LIBOR plus 1.82%
Parent Company and other non-bank subsidiaries [Member] | Other [Member]
Other Borrowings [Line Items]
Balance		$ 1,092	$ 0	$ 0
Rate		8.27%	0.00%	0.00%
Average Balance		$ 2,073	$ 0	$ 0
Rate		16.11%	0.00%	0.00%
Maximum Outstanding At Any Month End		$ 3,157	$ 0	$ 0
Parent Company and other non-bank subsidiaries [Member] | Other, Pershing [Member]
Other Borrowings [Line Items]
Balance		0
Parent Company and other non-bank subsidiaries [Member] | Subordinated debentures [Member]
Other Borrowings [Line Items]
Balance		$ 144,640	$ 0	$ 0
Rate		5.60%	0.00%	0.00%
Average Balance		$ 74,428	$ 0	$ 0
Rate		5.59%	0.00%	0.00%
Maximum Outstanding At Any Month End		$ 145,393	$ 0	$ 0
Parent Company and other non-bank subsidiaries [Member] | Subordinated debentures, 2016 issuance [Member]
Other borrowings, Other Disclosures [Abstract]
Amount of debt issuance		$ 150,000
Maturity date		Jun. 30, 2056
Stated interest rate		5.375%
Debt Instrument, Call Date, Earliest		Jun. 30, 2021
BOKF, NA [Member]
Other Borrowings [Line Items]
Balance		$ 5,564,353	6,277,866	3,726,277
Average Balance		$ 6,824,744	$ 5,880,647	$ 3,699,621
Rate		0.54%	0.36%	0.43%
Other borrowings, Maturities [Abstract]
2,017		$ 5,549,587
2,018		711
2,019		956
2,020		961
2,021		965
Thereafter		11,173
BOKF, NA [Member] | Funds purchased [Member]
Other Borrowings [Line Items]
Balance		$ 57,929	$ 491,192	$ 57,031
Rate		0.38%	0.15%	0.05%
Average Balance		$ 78,222	$ 73,219	$ 494,220
Rate		0.24%	0.09%	0.07%
Maximum Outstanding At Any Month End		$ 567,103	$ 491,192	$ 1,548,676
Other borrowings, Other Disclosures [Abstract]
Number of days to maturity, minimum		1 day
Number of days to maturity, maximum		90 days
BOKF, NA [Member] | Repurchase agreements [Member]
Other Borrowings [Line Items]
Balance		$ 668,661	$ 722,444	$ 1,187,489
Rate		0.02%	0.02%	0.04%
Average Balance		$ 589,145	$ 623,921	$ 928,767
Rate		0.04%	0.04%	0.06%
Maximum Outstanding At Any Month End		$ 668,661	$ 1,008,144	$ 1,187,489
Other borrowings, Other Disclosures [Abstract]
Number of days to maturity, maximum		90 days
Accrued interest payable		$ 0	0
BOKF, NA [Member] | Other Borrowings [Member]
Other Borrowings [Line Items]
Balance		4,837,763	4,837,880	2,133,774
Average Balance		$ 6,016,963	$ 4,957,175	$ 1,928,742
Rate		0.57%	0.33%	0.35%
BOKF, NA [Member] | Federal Home Loan Bank advances [Member]
Other Borrowings [Line Items]
Balance		$ 4,800,000	$ 4,800,000	$ 2,103,400
Rate		0.72%	0.48%	0.25%
Average Balance		$ 5,985,656	$ 4,921,739	$ 1,894,966
Rate		0.55%	0.28%	0.24%
Maximum Outstanding At Any Month End		$ 6,500,000	$ 5,000,000	$ 3,453,400
Other borrowings, Other Disclosures [Abstract]
Federal Home Loan Banks, Letters of credit issued to secure public funds		242,000
Unused credit available pursuant to the FHLB's collateral policies		1,300,000
BOKF, NA [Member] | GNMA repurchase liability [Member]
Other Borrowings [Line Items]
Balance		$ 22,471	$ 19,478	$ 14,298
Rate		4.26%	4.75%	5.05%
Average Balance		$ 15,637	$ 16,668	$ 17,343
Rate		4.74%	4.95%	5.20%
Maximum Outstanding At Any Month End		$ 22,471	$ 19,478	$ 24,980
BOKF, NA [Member] | Other [Member]
Other Borrowings [Line Items]
Balance		$ 15,292	$ 18,402	$ 16,076
Rate		2.66%	2.70%	2.73%
Average Balance		$ 15,670	$ 18,768	$ 16,433
Rate		2.41%	2.35%	2.32%
Maximum Outstanding At Any Month End		$ 15,797	$ 26,058	$ 16,582
BOKF, NA [Member] | Subordinated debentures [Member]
Other Borrowings [Line Items]
Balance		$ 0	$ 226,350	$ 347,983
Rate		0.00%	1.05%	2.35%
Average Balance		$ 140,414	$ 226,332	$ 347,892
Rate		1.35%	1.84%	2.50%
Maximum Outstanding At Any Month End		$ 226,434	$ 348,076	$ 347,983
BOKF, NA [Member] | Subordinated debentures, 2007 issuance [Member]
Other Borrowings [Line Items]
Balance			$ 226,000
Other borrowings, Other Disclosures [Abstract]
Amount of debt issuance		$ 250,000
Maturity date		May 15, 2017
Interest rate description		fixed rate of 5.75% through May 14, 2012 and is based on a floating rate of three-month LIBOR plus 0.69% thereafter
[1]	1 BOK Financial maintains control over the securities underlying overnight repurchase agreements and generally transfers control over securities underlying longer-term dealer repurchase agreements to the respective counterparty.

Federal and State Income Taxe80

Federal and State Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Deferred tax assets [Abstract]
Available for sale securities mark to market	$ 5,779	$ 0
Share-based compensation	9,360	10,522
Credit loss allowances	99,191	88,906
Valuation adjustments	12,222	6,957
Deferred compensation	30,262	25,950
Unearned fees	11,877	11,124
Other	42,541	34,169
Total deferred tax assets	211,232	177,628
Valuation Allowance [Abstract]
Valuation allowance	0	0
Deferred tax liabilities [Abstract]
Available for sale securities mark to market	0	14,828
Depreciation	25,877	22,080
Mortgage servicing rights	92,748	77,900
Lease financing	17,923	22,301
Other	45,363	41,904
Total deferred tax liabilities	181,911	179,013
Net deferred tax assets	29,321
Net deferred tax liabilities		(1,385)
Current income tax expense [Abstract]
Federal	107,379	117,566	$ 95,289
State	11,028	12,397	9,392
Total current income tax expense	118,407	129,963	104,681
Deferred income tax expense [Abstract]
Federal	(11,340)	8,397	36,521
State	(690)	1,024	2,949
Total deferred income tax expense	(12,030)	9,421	39,470
Total income tax expense	106,377	139,384	144,151
Effective Income Tax Rate Reconciliation, Amount [Abstract]
Federal statutory tax	118,530	151,075	153,870
Tax exempt revenue	(10,544)	(9,553)	(8,446)
Effect of state income taxes, net of federal benefit	6,478	9,082	9,054
Utilization of tax credits: [Abstract]
Low-income housing tax credits, net of amortization	(4,171)	(3,874)	(2,953)
Other tax credits	(2,085)	(2,085)	(2,109)
Bank-owned life insurance	(2,911)	(3,264)	(3,183)
Other, net	1,080	(1,997)	(2,082)
Total income tax expense	$ 106,377	$ 139,384	$ 144,151
Effective Income Tax Rate Reconciliation, Percent [Abstract]
Federal statutory tax (in hundredths)	35.00%	35.00%	35.00%
Tax exempt revenue (in hundredths)	(3.10%)	(2.20%)	(1.90%)
Effect of state income taxes, net of federal benefit (in hundredths)	1.90%	2.10%	2.10%
Utilization of tax credits: [Abstract]
Low-income housing tax credits, net of amortization (in hundredths)	(1.20%)	(0.90%)	(0.70%)
Other tax credits (in hundredths)	(0.60%)	(0.50%)	(0.50%)
Bank-owned life insurance (in hundredths)	(0.90%)	(0.70%)	(0.70%)
Other, net (in hundredths)	0.30%	(0.50%)	(0.50%)
Total (in hundredths)	31.40%	32.30%	32.80%
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Balance as of January 1	$ 13,232	$ 13,374	$ 12,058
Additions for tax for current year positions	5,640	2,226	3,813
Settlements during the period	0	0	0
Lapses of applicable statute of limitations	(3,031)	(2,368)	(2,497)
Balance as of December 31	15,841	13,232	13,374
Unrecognized Tax Benefits that Would Impact Effective Tax Rate	10,300
Unrecognized Tax Benefits, Income Tax Penalties and Interest Expense	1,000	1,000	$ 1,500
Unrecognized Tax Benefits, Penalties and Interest Accrued	$ 3,500	$ 3,300
Unrecognized Tax Benefits, Number of Reporting Periods Open for Examination, Federal	3 years
Unrecognized Tax Benefits, Number of Reporting Periods Open for Examination, State, Minimum	3 years
Unrecognized Tax Benefits, Number of Reporting Periods Open for Examination, State, Maximum	6 years

Employee Benefits (Details)

Employee Benefits (Details) - USD ($)	12 Months Ended
	Dec. 31, 2016		Dec. 31, 2015		Dec. 31, 2014
Thrift Plan - Defined Contribution [Abstract]
Employee base compensation company match employee contributions (in hundredths)	6.00%
Employer matching rate for employee contributions minimum (in hundredths)	50.00%
Minimum years of service for employees to obtain maximum employer matching (in years)	4 years
Employer matching rate for employee contributions maximum (in hundredths)	200.00%
Maximum years of service for employees to obtain minimum employer matching (in years)	15 years
Non-elective annual contribution for qualified employees	$ 750
Annual base employee compensation to qualify for non-elective employer contributions maximum	40,000
Employer discretionary contribution amount	$ 530,000		$ 605,000		$ 662,000
Vesting period for employer contributions (in years)	5 years
Thrift Plan expenses	$ 22,400,000		20,600,000		18,600,000
Incentive compensation plans [Abstract]
Expense related to cash-based incentive compensation plans	$ 128,100,000		114,300,000		111,700,000
Pension Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Interest percentage added to the five-year trailing average of five-year Treasury Securities	1.50%
Interest percentage accrued on employee account balances, Minimum	3.00%
Interest percentage accrued on employee account balances, Maximum	5.00%
Interest percentage accrued on employee account balances for current year	3.00%
Change in projected benefit obligation [Roll Forward]
Projected benefit obligation at beginning of year	$ 38,797,000	[1],[2]	45,224,000
Interest cost	1,309,000		1,487,000
Actuarial loss (gain)	(55,000)		(2,702,000)
Benefits paid	(5,087,000)		(5,212,000)
Projected benefit obligation at end of year	34,964,000	[1],[2]	38,797,000	[1],[2]	45,224,000
Change in plan assets [Roll Forward]
Plan assets at fair value at beginning of year	44,190,000		49,443,000
Actual return on plan assets	2,666,000		(41,000)
Benefits paid	(5,087,000)		(5,212,000)
Plan assets at fair value at end of year	41,769,000		44,190,000		$ 49,443,000
Defined Benefit Plan, Funded Status of Plan [Abstract]
Funded status of the plan	6,805,000		5,393,000
Components of net periodic benefit costs [Abstract]
Interest cost	1,309,000		1,487,000
Expected return on plan assets	(2,167,000)		(2,706,000)
Other	(741,000)		1,849,000
Net periodic pension cost	$ (1,599,000)		$ 630,000
Weighted-average assumptions [Abstract]
Discount rate (in hundredths)	3.43%		3.54%
Expected return on plan assets (in hundredths)	5.00%		5.00%
Estimated Future Benefit Payments [Abstract]
2,017	$ 2,706,000
2,018	3,072,000
2,019	3,402,000
2,020	3,090,000
2,021	2,934,000
Thereafter	28,044,000
Total estimated future benefit payments	43,248,000
Defined Benefit Plan, Information about Plan Assets [Abstract]
Maximum tax deductible contributions to defined benefit plan	$ 12,000,000
Equity Securities [Member] | Pension Plan [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Percentage of equities and bonds included in portfolio mix of fund used for defined benefit plan (in hundredths)	60.00%
Bonds [Member] | Pension Plan [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Percentage of equities and bonds included in portfolio mix of fund used for defined benefit plan (in hundredths)	40.00%
[1]	Projected benefit obligation equals accumulated benefit obligation.
[2]	Projected benefit obligation is based on January 1 measurement date.

Share-Based Compensation Plan82

Share-Based Compensation Plans (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended	12 Months Ended
	Jan. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Share-based Compensation Arrangements by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Roll Forward]
Total shares awarded under executive incentive plan (in shares)		293,110
Stock Options [Member]
Share-based Compensation Arrangements by Share-based Payment Award, Options, Outstanding, Number of Options [Abstract]
Number of options outstanding, Beginning balance (in shares)	218,524	480,035	793,891	1,135,105
Options awarded (in shares)		0	0	0
Options exercised (in shares)		(249,404)	(286,678)	(323,004)
Options forfeited (in shares)		(4,098)	(22,304)	(15,509)
Options expired (in shares)		(8,009)	(4,874)	(2,701)
Number of options outstanding, Ending balance (in shares)		218,524	480,035	793,891
Options shares vested (in shares)		93,117	243,395	347,633
Share-based Compensation Arrangements by Share-based Payment Award, Options, Weighted Average Exercise Price [Abstract]
Options outstanding, weighted average exercise price, beginning balance (in dollars per share)	$ 51.95	$ 49.75	$ 49.05	$ 49.09
Options awarded, weighted average exercise price (in dollars per share)		0	0	0
Options exercised, weighted average exercise price (in dollars per share)		47.60	47.86	49.17
Options forfeited, weighted average exercise price (in dollars per share)		55.44	48.90	45.71
Options expired, weighted average exercise price (in dollars per share)		53.43	51.32	47.98
Options outstanding, weighted average exercise price, ending balance (in dollars per share)		51.95	49.75	49.05
Options vested, weighted average exercise price (in dollars per share)		$ 46.22	$ 48.17	$ 48.85
Share-based Compensation Arrangements by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Options outstanding, aggregate intrinsic value		$ 6,793	$ 4,821	$ 8,725	$ 19,564
Options vested, aggregate intrinsic value		3,429	2,829	3,889
Options exercised, aggregate intrinsic value		6,200	5,100	5,500
Share-based Compensation Expense Recognized		254	362	826
Share-based Compensation Costs, Including Costs That May Be Recognized As Future Expense [Abstract]
Unrecognized compensation cost of unvested awards, for future periods		$ 229
Stock Options [Member] | Exercise Price 36.65 [Member]
Share-based Compensation Arrangements by Share-based Payment Award, Options, Outstanding, Number of Options [Abstract]
Number of options outstanding, Beginning balance (in shares)	36,722
Number of options outstanding, Ending balance (in shares)		36,722
Options shares vested (in shares)		36,722
Share-based Compensation Arrangements by Share-based Payment Award, Options, Weighted Average Exercise Price [Abstract]
Options outstanding, weighted average exercise price, beginning balance (in dollars per share)	$ 36.65
Options outstanding, weighted average exercise price, ending balance (in dollars per share)		$ 36.65
Options vested, weighted average exercise price (in dollars per share)		$ 36.65
Share-based Compensation Arrangements by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Weighted average remaining contractual life of options outstanding (in years)		1 year 164 days
Weighted average remaining contractual life of options vested (in years)		1 year 164 days
Stock Options [Member] | Exercise Price 48.30 [Member]
Share-based Compensation Arrangements by Share-based Payment Award, Options, Outstanding, Number of Options [Abstract]
Number of options outstanding, Beginning balance (in shares)	14,208
Number of options outstanding, Ending balance (in shares)		14,208
Options shares vested (in shares)		6,906
Share-based Compensation Arrangements by Share-based Payment Award, Options, Weighted Average Exercise Price [Abstract]
Options outstanding, weighted average exercise price, beginning balance (in dollars per share)	$ 48.30
Options outstanding, weighted average exercise price, ending balance (in dollars per share)		$ 48.30
Options vested, weighted average exercise price (in dollars per share)		$ 48.30
Share-based Compensation Arrangements by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Weighted average remaining contractual life of options outstanding (in years)		2 years 117 days
Weighted average remaining contractual life of options vested (in years)		1 year 208 days
Stock Options [Member] | Exercise Price 48.46 [Member]
Share-based Compensation Arrangements by Share-based Payment Award, Options, Outstanding, Number of Options [Abstract]
Number of options outstanding, Beginning balance (in shares)	21,138
Number of options outstanding, Ending balance (in shares)		21,138
Options shares vested (in shares)		21,138
Share-based Compensation Arrangements by Share-based Payment Award, Options, Weighted Average Exercise Price [Abstract]
Options outstanding, weighted average exercise price, beginning balance (in dollars per share)	$ 48.46
Options outstanding, weighted average exercise price, ending balance (in dollars per share)		$ 48.46
Options vested, weighted average exercise price (in dollars per share)		$ 48.46
Share-based Compensation Arrangements by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Weighted average remaining contractual life of options outstanding (in years)		296 days
Weighted average remaining contractual life of options vested (in years)		296 days
Stock Options [Member] | Exercise Price 54.33 [Member]
Share-based Compensation Arrangements by Share-based Payment Award, Options, Outstanding, Number of Options [Abstract]
Number of options outstanding, Beginning balance (in shares)	3,628
Number of options outstanding, Ending balance (in shares)		3,628
Options shares vested (in shares)		3,628
Share-based Compensation Arrangements by Share-based Payment Award, Options, Weighted Average Exercise Price [Abstract]
Options outstanding, weighted average exercise price, beginning balance (in dollars per share)	$ 54.33
Options outstanding, weighted average exercise price, ending balance (in dollars per share)		$ 54.33
Options vested, weighted average exercise price (in dollars per share)		$ 54.33
Share-based Compensation Arrangements by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Weighted average remaining contractual life of options outstanding (in years)		11 days
Weighted average remaining contractual life of options vested (in years)		11 days
Stock Options [Member] | Exercise Price 55.74 [Member]
Share-based Compensation Arrangements by Share-based Payment Award, Options, Outstanding, Number of Options [Abstract]
Number of options outstanding, Beginning balance (in shares)	51,570
Number of options outstanding, Ending balance (in shares)		51,570
Options shares vested (in shares)		5,008
Share-based Compensation Arrangements by Share-based Payment Award, Options, Weighted Average Exercise Price [Abstract]
Options outstanding, weighted average exercise price, beginning balance (in dollars per share)	$ 55.74
Options outstanding, weighted average exercise price, ending balance (in dollars per share)		$ 55.74
Options vested, weighted average exercise price (in dollars per share)		$ 55.74
Share-based Compensation Arrangements by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Weighted average remaining contractual life of options outstanding (in years)		4 years 102 days
Weighted average remaining contractual life of options vested (in years)		2 years 11 days
Stock Options [Member] | Exercise Price 55.94 [Member]
Share-based Compensation Arrangements by Share-based Payment Award, Options, Outstanding, Number of Options [Abstract]
Number of options outstanding, Beginning balance (in shares)	48,800
Number of options outstanding, Ending balance (in shares)		48,800
Options shares vested (in shares)		12,260
Share-based Compensation Arrangements by Share-based Payment Award, Options, Weighted Average Exercise Price [Abstract]
Options outstanding, weighted average exercise price, beginning balance (in dollars per share)	$ 55.94
Options outstanding, weighted average exercise price, ending balance (in dollars per share)		$ 55.94
Options vested, weighted average exercise price (in dollars per share)		$ 55.94
Share-based Compensation Arrangements by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Weighted average remaining contractual life of options outstanding (in years)		3 years 29 days
Weighted average remaining contractual life of options vested (in years)		1 year 263 days
Stock Options [Member] | Exercise Price 58.76 [Member]
Share-based Compensation Arrangements by Share-based Payment Award, Options, Outstanding, Number of Options [Abstract]
Number of options outstanding, Beginning balance (in shares)	42,458
Number of options outstanding, Ending balance (in shares)		42,458
Options shares vested (in shares)		7,455
Share-based Compensation Arrangements by Share-based Payment Award, Options, Weighted Average Exercise Price [Abstract]
Options outstanding, weighted average exercise price, beginning balance (in dollars per share)	$ 58.76
Options outstanding, weighted average exercise price, ending balance (in dollars per share)		$ 58.76
Options vested, weighted average exercise price (in dollars per share)		$ 58.76
Share-based Compensation Arrangements by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Weighted average remaining contractual life of options outstanding (in years)		3 years 227 days
Weighted average remaining contractual life of options vested (in years)		1 year 256 days
Non-vested Common Stock [Member]
Share-based Compensation Arrangements by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Share-based Compensation Expense Recognized		$ 10,200	$ 12,000	$ 10,000
Share-based Compensation Costs, Including Costs That May Be Recognized As Future Expense [Abstract]
Unrecognized compensation cost of unvested awards, for future periods		14,100
Unrecognized compensation cost of unvested awards, Amount to be expensed in 2017		9,300
Unrecognized compensation cost of unvested awards, Amount to be expensed in 2018		4,700
Unrecognized compensation cost of unvested awards, Amount to be expensed in 2019		$ 89
Share-based Compensation Arrangements by Share-based Payment Award, Restricted Stock, Nonvested, Number of Shares [Roll Forward]
Non-vested common shares awarded, beginning of period (in shares)	786,706	791,109	688,611	647,989
Non-vested common shares granted during period (in shares)		256,670	312,755	206,621
Non-vested shares that vested during period (in shares)		(213,941)	(114,045)	(140,820)
Non-vested shares that forfeited during period (in shares)		(47,132)	(96,212)	(25,179)
Non-vested common shares awarded, end of period (in shares)		786,706	791,109	688,611
Share-based Compensation Arrangements by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Roll Forward]
Weighted Average Grant Date Fair Value, Granted		$ 55.35	$ 57.66	$ 64.96
Weighted Average Grant Date Fair Value, Vested		55.87	50.15	44.56
Weighted average grant date fair value non-vested stock awards forfeited (in dollars per share)		$ 57.86	$ 58.33	$ 56.26
Subsequent Event [Member] | Non-vested Common Stock [Member]
Share-based Compensation Costs, Including Costs That May Be Recognized As Future Expense [Abstract]
Unrecognized compensation cost of unvested awards, for future periods	$ 14,300
Share-based Compensation Arrangements by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Roll Forward]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period	170,785
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value	$ 83.50

Related Parties Related Parti83

Related Parties Related Parties (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Loans and Leases Receivable, Related Parties [Roll Forward]
Lease payments on office space in facilities owned by related party afffiliates	$ 25,800	$ 25,200	$ 25,000
Directors and Senior Management [Member]
Loans and Leases Receivable, Related Parties [Roll Forward]
Beginning balance	594,225	103,395
Advances	884,511	3,582,384
Payments	(1,123,747)	(3,104,004)
Adjustments	(218,044)	12,450
Ending balance	136,945	594,225	103,395
Board of Directors Chairman [Member]
Loans and Leases Receivable, Related Parties [Roll Forward]
Lease payments on office space in facilities owned by related party afffiliates	$ 1,100	975	$ 1,100
Executive Officer [Member]
Loans and Leases Receivable, Related Parties [Roll Forward]
Percentage of investment funds' assets held by clients	94.00%
Assets Held in Cavanal Hill Funds	$ 3,800,000
BOKF, NA [Member] | Affiliated Entity [Member]
Loan Commitments and Equity Investments [Abstract]
Maximum percentage of unimpaired capital on loan commitments and equity investments to a single affiliate (in hundredths)	10.00%
Maximum percentage of unimpaired capital on loan commitments and equity investments to all affiliates (in hundredths)	20.00%
Maximum loan commitments and equity investments to a single affiliate	$ 287,000
Maximum loan commitments and equity investments to all affiliates	573,000
Largest loan commitment and equity investment to a single affiliate	220,000
Aggregate loan commitment and equity investment to all affiliates	337,000	330,000
Outstanding amounts to all affiliates	39,000	$ 244,000
Largest amount outstanding to a single affiliate	$ 24,000

Commitments and Contingent Li84

Commitments and Contingent Liabilities (Details)	12 Months Ended
	Dec. 31, 2016USD ($)shares	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)
Other Commitments [Abstract]
The Net Asset Value of Units in Mutual Funds (per unit)	1
Minimum Average Cash Balance Required to be Maintained at Federal Reserve by Subsidiary Bank	$ 1,900,000,000	$ 1,800,000,000
Operating Leases, Rent Expense, Net [Abstract]
Operating Leases, Rent Expense, Net	25,800,000	$ 25,200,000	$ 25,000,000
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
Operating Leases, Future Minimum Payments, Due in 2017	22,500,000
Operating Leases, Future Minimum Payments, Due in 2018	20,100,000
Operating Leases, Future Minimum Payments, Due in 2019	19,600,000
Operating Leases, Future Minimum Payments, Due in 2020	16,200,000
Operating Leases, Future Minimum Payments, Due in 2021	13,400,000
Operating Leases, Future Minimum Payments, Due Thereafter	$ 56,800,000
Visa Membership [Member]
Loss Contingencies [Line Items]
Number of Visa Class B Shares Owned by Entity (in shares) | shares	252,233
Number of Visa Class A Shares Visa Class B Shares Are Convertible To (in shares) | shares	415,755
Deposit Account Posting Class Action [Member] | Settled Litigation [Member]
Litigation Settlement [Abstract]
Litigation Settlement, Amount	$ 7,800,000
Misuse of Revenues Pledged to Municipal Bonds [Member] | Judicial Ruling [Member]
Litigation Settlement [Abstract]
Litigation Settlement, Amount	600,000
Outstanding principal, accrued interest and other amounts required by bond documents	73,000,000
Disgorged fees	$ 1,067,721
Misuse of Revenues Pledged to Municipal Bonds [Member] | Pending Litigation [Member]
Litigation Settlement [Abstract]
Loss Contingency, Number of Plaintiffs	2
Bank Participation in Fraudulent Sale of Securities by Principals [Member] | Pending Litigation [Member]
Litigation Settlement [Abstract]
Loss Contingency, Number of Plaintiffs	19
Municipal Bond Purchase by Elected Treasurer [Member] | Settled Litigation [Member]
Litigation Settlement [Abstract]
Litigation Settlement, Amount	$ 125,000
Municipal Bond Purchase by Elected Treasurer [Member] | Pending Litigation [Member]
Litigation Settlement [Abstract]
Loss Contingency, Damages Sought, Value	$ 5,600,000

Commitments and Contingent Li85

Commitments and Contingent Liabilities Variable Interest Entities (Details) $ in Thousands	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)
BOKF Equity, LLC [Member]
Variable Interest Entity [Line Items]
Number of Private Equity Funds of which the Entity is a General Partner	2
Contingent Obligation For Additional Investments In Private Equity Funds	$ 2,600
Loans [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net	10,000	$ 10,000
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets and Liabilities, Net	44,488	16,916
Other Assets [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net	58,725	75,131
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets and Liabilities, Net	175,390	100,780
Other Liabilities [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net	3,189	2,198
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets and Liabilities, Net	78,357	20,891
Other borrowings [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net	12,056	13,795
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets and Liabilities, Net	0	0
Non-Controlling Interests [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net	31,503	37,083
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets and Liabilities, Net	0	0
Private Equity Funds Variable Interest Entities [Member] | Loans [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net	0	0
Private Equity Funds Variable Interest Entities [Member] | Other Assets [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net	17,357	22,472
Private Equity Funds Variable Interest Entities [Member] | Other Liabilities [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net	0	0
Private Equity Funds Variable Interest Entities [Member] | Other borrowings [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net	0	0
Private Equity Funds Variable Interest Entities [Member] | Non-Controlling Interests [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net	13,237	17,823
Tax Credit Variable Interest Entities [Member] | Loans [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net	10,000	10,000
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets and Liabilities, Net	44,488	16,916
Tax Credit Variable Interest Entities [Member] | Other Assets [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net	11,585	12,206
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets and Liabilities, Net	143,715	85,274
Tax Credit Variable Interest Entities [Member] | Other Liabilities [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net	0	0
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets and Liabilities, Net	63,329	14,572
Tax Credit Variable Interest Entities [Member] | Other borrowings [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net	10,964	10,964
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets and Liabilities, Net	0	0
Tax Credit Variable Interest Entities [Member] | Non-Controlling Interests [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net	10,000	10,000
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets and Liabilities, Net	0	0
Other Variable Interest Entities [Member] | Loans [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net	0	0
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets and Liabilities, Net	0	0
Other Variable Interest Entities [Member] | Other Assets [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net	29,783	40,453
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets and Liabilities, Net	31,675	15,506
Other Variable Interest Entities [Member] | Other Liabilities [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net	3,189	2,198
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets and Liabilities, Net	15,028	6,319
Other Variable Interest Entities [Member] | Other borrowings [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net	1,092	2,831
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets and Liabilities, Net	0	0
Other Variable Interest Entities [Member] | Non-Controlling Interests [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net	8,266	9,260
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets and Liabilities, Net	$ 0	$ 0

Commitments and Contingent Li86

Commitments and Contingent Liabilities Commitments (Details) - Principal Shareholder of more than 5% [Member] - Oklahoma Historic State Income Tax Credit [Member] $ in Millions	12 Months Ended
	Dec. 31, 2016USD ($)
Purchase Commitment, Excluding Long-term Commitment [Line Items]
Original commitment to purchase tax credits from related party	$ 7.5
Related Party Transaction, Purchases from Related Party	$ 3.8

Earnings Per Share (Details)

Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Numerator: [Abstract]:
Net income attributable to BOK Financial Corp. shareholders	$ 232,668	$ 288,565	$ 292,435
Less: Earnings allocated to participating securities	2,883	3,383	3,239
Numerator for basic earnings per share - income available to common shareholders	229,785	285,182	289,196
Effect of reallocating undistributed earnings of participating securities	1	3	4
Numerator for diluted earnings per share - income available to common shareholders	$ 229,786	$ 285,185	$ 289,200
Denominator: [Abstract]
Weighted average shares outstanding	65,901,110	68,397,215	69,159,902
Less: Participating securities included in weighted average shares outstanding (in shares)	815,483	802,526	765,708
Denominator for basic earnings per common share (in shares)	65,085,627	67,594,689	68,394,194
Dilutive effect of employee stock compensation plans (in shares)	58,271	96,969	150,576
Denominator for diluted earnings per common share (in shares)	65,143,898	67,691,658	68,544,770
Basic (in dollars per share)	$ 3.53	$ 4.22	$ 4.23
Diluted earnings per share (per share)	$ 3.53	$ 4.21	$ 4.22
Excludes employee stock options with exercise prices greater than current market price.	0	0	0

Shareholders' Equity (Details)

Shareholders' Equity (Details) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2016USD ($)$ / sharesshares	Dec. 31, 2015$ / sharesshares	Dec. 31, 2014shares
Common Stock [Abstract]
Common stock, authorized (in shares) | shares	2,500,000,000	2,500,000,000
Common stock, par value (in dollars per share) | $ / shares	$ 0.00006	$ 0.00006
Perpetual stock [Member]
Preferred Stock [Abstract]
Preferred stock, authorized (in shares) | shares	1,000,000,000
Preferred stock at par value (in dollars per share) | $ / shares	$ 0.00005
Preferred stock conversion rate	one share of Common Stock for each 36 shares of Series A Preferred Stock at the option of the holder
Preferred stock, Rate of annual cumulative dividends (in hundredths)	10.00%
Preferred stock, Liquidation preference per share | $ / shares	$ 0.06
Preferred stock, Aggregate liquidation preference | $	$ 15
Preferred Stock, Shares Outstanding | shares	0	0	0
Common Stock [Member]
Common Stock [Abstract]
Common stock, authorized (in shares) | shares	2,500,000,000
Common stock, par value (in dollars per share) | $ / shares	$ 0.00006
Common stock, number of vote per share	1

Shareholders' Equity Regulatory

Shareholders' Equity Regulatory Capital (Details) - USD ($) $ in Thousands		Dec. 31, 2016	Dec. 31, 2015
Common Equity Tier 1 (to Risk Weighted Assets) [Abstract]
Minimum Capital Requirement, Common equity Tier 1 Capital to Risk Weighted Assets		4.50%	4.50%
Capital Conservation Buffer, Common equity Tier 1 to Risk Weighted Assets	[1]	2.50%	2.50%
Minimum Capital Requirement Including Capital Conservation Buffer, Common equity Tier 1 to Risk Weighted Assets		7.00%	7.00%
Common Equity Tier 1 Capital		$ 2,834,532	$ 2,842,193
Common Equity Tier One Risk Based Capital to Risk Weighted Assets		11.21%	12.13%
Tier I Capital (to Risk Weighted Assets) [Abstract]
Minimum Capital Requirement, Tier 1 Capital to Risk Weighted Assets		6.00%	6.00%
Capital Conservation Buffer, Tier 1 Capital to Risk Weighted Assets	[1]	2.50%	2.50%
Minimum Capital Requirement Including Capital Conservation Buffer, Tier One to Risk Weighted Assets		8.50%	8.50%
Tier 1 Capital		$ 2,834,532	$ 2,842,193
Tier I Capital to Risk Weighted Assets		11.21%	12.13%
Total Capital (to Risk Weighted Assets) [Abstract]
Minimum Capital Requirement, Total Capital to Risk Weighted Assets		8.00%	8.00%
Capital Conservation Buffer, Total Capital to Risk Weighted Assets	[1]	2.50%	2.50%
Minimum Capital Requirement Including Capital Conservation Buffer, Total Capital to Risk Weighted Assets		10.50%	10.50%
Total Capital		$ 3,238,323	$ 3,116,144
Total Capital to Risk Weighted Assets		12.81%	13.30%
Tier I Capital (to Average Assets) [Abstract]
Minimum Capital Requirement, Tier 1 Capital to Average Assets		4.00%	4.00%
Minimum Capital Requirements Including Capital Conservation Buffer, Tier One Capital to Average Assets		4.00%	4.00%
Tier I Capital to Average Assets		8.72%	9.25%
Phased in Capital Conservation Buffer		0.625%
Fully Phased In Capital Conservation Buffer		2.50%
BOKF, NA [Member]
Common Equity Tier 1 (to Risk Weighted Assets) [Abstract]
Common Equity Tier 1 Capital Ratio Required to be Well Capitalized		6.50%	6.50%
Minimum Capital Requirement, Common equity Tier 1 Capital to Risk Weighted Assets		4.50%	4.50%
Minimum Capital Requirement Including Capital Conservation Buffer, Common equity Tier 1 to Risk Weighted Assets		4.50%	4.50%
Common Equity Tier 1 Capital		$ 2,609,450	$ 2,385,323
Common Equity Tier One Risk Based Capital to Risk Weighted Assets		10.65%	10.26%
Tier I Capital (to Risk Weighted Assets) [Abstract]
Tier I Capital Ratio Required to be Well Capitalized		8.00%	8.00%
Minimum Capital Requirement, Tier 1 Capital to Risk Weighted Assets		6.00%	6.00%
Minimum Capital Requirement Including Capital Conservation Buffer, Tier One to Risk Weighted Assets		6.00%	6.00%
Tier 1 Capital		$ 2,609,450	$ 2,385,323
Tier I Capital to Risk Weighted Assets		10.65%	10.26%
Total Capital (to Risk Weighted Assets) [Abstract]
Total Capital Ratio Required to be Well Capitalized		10.00%	10.00%
Minimum Capital Requirement, Total Capital to Risk Weighted Assets		8.00%	8.00%
Minimum Capital Requirement Including Capital Conservation Buffer, Total Capital to Risk Weighted Assets		8.00%	8.00%
Total Capital		$ 2,866,949	$ 2,657,935
Total Capital to Risk Weighted Assets		11.70%	11.43%
Tier I Capital (to Average Assets) [Abstract]
Leverage Ratio Required to be Well Capitalized		5.00%	5.00%
Minimum Capital Requirement, Tier 1 Capital to Average Assets		4.00%	4.00%
Minimum Capital Requirements Including Capital Conservation Buffer, Tier One Capital to Average Assets		4.00%	4.00%
Tier I Capital to Average Assets		8.11%	7.81%
Mobank [Member]
Common Equity Tier 1 (to Risk Weighted Assets) [Abstract]
Common Equity Tier 1 Capital Ratio Required to be Well Capitalized	[2]	6.50%
Minimum Capital Requirement, Common equity Tier 1 Capital to Risk Weighted Assets	[2]	4.50%
Minimum Capital Requirement Including Capital Conservation Buffer, Common equity Tier 1 to Risk Weighted Assets	[2]	4.50%
Common Equity Tier 1 Capital	[2]	$ 54,616
Common Equity Tier One Risk Based Capital to Risk Weighted Assets	[2]	10.03%
Tier I Capital (to Risk Weighted Assets) [Abstract]
Tier I Capital Ratio Required to be Well Capitalized	[2]	8.00%
Minimum Capital Requirement, Tier 1 Capital to Risk Weighted Assets	[2]	6.00%
Minimum Capital Requirement Including Capital Conservation Buffer, Tier One to Risk Weighted Assets	[2]	6.00%
Tier 1 Capital	[2]	$ 54,616
Tier I Capital to Risk Weighted Assets	[2]	10.03%
Total Capital (to Risk Weighted Assets) [Abstract]
Total Capital Ratio Required to be Well Capitalized	[2]	10.00%
Minimum Capital Requirement, Total Capital to Risk Weighted Assets	[2]	8.00%
Minimum Capital Requirement Including Capital Conservation Buffer, Total Capital to Risk Weighted Assets	[2]	8.00%
Total Capital	[2]	$ 54,617
Total Capital to Risk Weighted Assets	[2]	10.03%
Tier I Capital (to Average Assets) [Abstract]
Leverage Ratio Required to be Well Capitalized	[2]	5.00%
Minimum Capital Requirement, Tier 1 Capital to Average Assets	[2]	4.00%
Minimum Capital Requirements Including Capital Conservation Buffer, Tier One Capital to Average Assets	[2]	4.00%
Tier I Capital to Average Assets	[2]	8.37%
[1]	Capital conservation buffer is effective January 1, 2016 and is phased in through 2019. The phased in capital conservation buffer at December 31, 2016 is 0.625%. The fully phased in requirement of 2.50% is included in the table above.
[2]	Missouri Bank and Trust Company of Kansas City dba Mobank was acquired by BOK Financial effective December 1, 2016

Shareholders' Equity Accumulate

Shareholders' Equity Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance		$ 21,587	$ 56,673	$ (25,623)
Net change in unrealized gain (loss)		(41,521)	(46,803)	136,775
Reclassification adjustments included in earnings: [Abstract]
Interest revenue, Investment securities, Taxable securities		(112)	(503)	(1,216)
Interest expense, Subordinated debentures		0	121	296
Net impairment losses recognized in earnings		0	1,819	373
Gain on available for sale securities, net		(11,675)	(12,058)	(1,539)
Other comprehensive income (loss), before income taxes		(53,308)	(57,424)	134,689
Federal and state income taxes	[1]	(20,754)	(22,338)	52,393
Other comprehensive income (loss), net of income taxes		(32,554)	(35,086)	82,296
Ending balance		(10,967)	21,587	56,673
Accumulated Net Investment Gain (Loss) Attributable to Parent [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance		23,284	59,239	(23,175)
Net change in unrealized gain (loss)		(41,333)	(48,607)	136,050
Reclassification adjustments included in earnings: [Abstract]
Interest revenue, Investment securities, Taxable securities		0	0	0
Interest expense, Subordinated debentures		0	0	0
Net impairment losses recognized in earnings		0	1,819	373
Gain on available for sale securities, net		(11,675)	(12,058)	(1,539)
Other comprehensive income (loss), before income taxes		(53,008)	(58,846)	134,884
Federal and state income taxes	[1]	(20,637)	(22,891)	52,470
Other comprehensive income (loss), net of income taxes		(32,371)	(35,955)	82,414
Ending balance		(9,087)	23,284	59,239
Accumulated Net Investment Gain (Loss) Attributable to Parent [Member] | Perpetual Preferred, Equity Securities and Mutual Funds [Member]
Reclassification adjustments included in earnings: [Abstract]
Ending balance		2,400
Accumulated Unrealized Gain on AFS Securities Transferred to Investment Securities [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance		68	376	1,118
Net change in unrealized gain (loss)		0	0	0
Reclassification adjustments included in earnings: [Abstract]
Interest revenue, Investment securities, Taxable securities		(112)	(503)	(1,216)
Interest expense, Subordinated debentures		0	0	0
Net impairment losses recognized in earnings		0	0	0
Gain on available for sale securities, net		0	0	0
Other comprehensive income (loss), before income taxes		(112)	(503)	(1,216)
Federal and state income taxes	[1]	(44)	(195)	(474)
Other comprehensive income (loss), net of income taxes		(68)	(308)	(742)
Ending balance		0	68	376
Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance		(1,765)	(2,868)	(3,311)
Net change in unrealized gain (loss)		(188)	1,804	725
Reclassification adjustments included in earnings: [Abstract]
Interest revenue, Investment securities, Taxable securities		0	0	0
Interest expense, Subordinated debentures		0	0	0
Net impairment losses recognized in earnings		0	0	0
Gain on available for sale securities, net		0	0	0
Other comprehensive income (loss), before income taxes		(188)	1,804	725
Federal and state income taxes	[1]	(73)	701	282
Other comprehensive income (loss), net of income taxes		(115)	1,103	443
Ending balance		(1,880)	(1,765)	(2,868)
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance		0	(74)	(255)
Net change in unrealized gain (loss)		0	0	0
Reclassification adjustments included in earnings: [Abstract]
Interest revenue, Investment securities, Taxable securities		0	0	0
Interest expense, Subordinated debentures		0	121	296
Net impairment losses recognized in earnings		0	0	0
Gain on available for sale securities, net		0	0	0
Other comprehensive income (loss), before income taxes		0	121	296
Federal and state income taxes	[1]	0	47	115
Other comprehensive income (loss), net of income taxes		0	74	181
Ending balance		$ 0	$ 0	$ (74)
[1]	Calculated using 39% effective tax rate.

Reportable Segments (Details)

Reportable Segments (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Segment Reporting Information [Line Items]
Net interest and dividend revenue from external sources	$ 747,228	$ 703,354	$ 665,194
Net interest revenue (expense) from internal sources	0	0	0
Net interest and dividend revenue	747,228	703,354	665,194
Provision for credit losses	65,000	34,000	0
Net interest and dividend revenue after provision for credit losses	682,228	669,354	665,194
Other operating revenue	674,020	658,480	621,958
Other operating expense	1,017,590	896,191	847,522
Net direct contribution	338,658	431,643	439,630
Gain (loss) on financial instruments, net	0	0	0
Change in fair value of mortgage servicing rights	0	0	0
Gain (loss) on repossessed assets, net	0	0	0
Corporate expense allocations	0	0	0
Net income before taxes	338,658	431,643	439,630
Federal and state income taxes	106,377	139,384	144,151
Net income	232,281	292,259	295,479
Net income (loss) attributable to non-controlling interests	(387)	3,694	3,044
Net income attributable to BOK Financial Corp. shareholders	232,668	288,565	292,435
Average assets	32,278,402	30,574,755	27,998,858
Operating Segments [Member] | Commercial [Member]
Segment Reporting Information [Line Items]
Net interest and dividend revenue from external sources	492,967	439,751	382,331
Net interest revenue (expense) from internal sources	(58,781)	(52,313)	(40,083)
Net interest and dividend revenue	434,186	387,438	342,248
Provision for credit losses	32,959	(6,748)	(7,447)
Net interest and dividend revenue after provision for credit losses	401,227	394,186	349,695
Other operating revenue	195,521	177,729	171,390
Other operating expense	216,451	202,804	195,706
Net direct contribution	380,297	369,111	325,379
Gain (loss) on financial instruments, net	10	0	0
Change in fair value of mortgage servicing rights	0	0	0
Gain (loss) on repossessed assets, net	669	708	(3,187)
Corporate expense allocations	35,760	43,279	45,502
Net income before taxes	345,216	326,540	276,690
Federal and state income taxes	134,289	127,024	107,632
Net income	210,927	199,516	169,058
Net income (loss) attributable to non-controlling interests	0	0	0
Net income attributable to BOK Financial Corp. shareholders	210,927	199,516	169,058
Average assets	16,998,626	16,284,527	15,394,957
Operating Segments [Member] | Consumer [Member]
Segment Reporting Information [Line Items]
Net interest and dividend revenue from external sources	85,998	84,848	81,852
Net interest revenue (expense) from internal sources	37,777	28,503	26,813
Net interest and dividend revenue	123,775	113,351	108,665
Provision for credit losses	4,927	6,934	5,477
Net interest and dividend revenue after provision for credit losses	118,848	106,417	103,188
Other operating revenue	224,802	218,095	214,657
Other operating expense	249,744	203,070	207,131
Net direct contribution	93,906	121,442	110,714
Gain (loss) on financial instruments, net	(26,252)	(4,712)	12,406
Change in fair value of mortgage servicing rights	(2,193)	(4,853)	(16,445)
Gain (loss) on repossessed assets, net	979	916	1,418
Corporate expense allocations	66,411	74,936	64,531
Net income before taxes	29	37,857	43,562
Federal and state income taxes	11	14,726	16,946
Net income	18	23,131	26,616
Net income (loss) attributable to non-controlling interests	0	0	0
Net income attributable to BOK Financial Corp. shareholders	18	23,131	26,616
Average assets	8,722,372	8,836,327	8,373,317
Operating Segments [Member] | Wealth Management [Member]
Segment Reporting Information [Line Items]
Net interest and dividend revenue from external sources	33,006	24,744	23,817
Net interest revenue (expense) from internal sources	29,043	24,043	20,959
Net interest and dividend revenue	62,049	48,787	44,776
Provision for credit losses	(801)	(1,083)	213
Net interest and dividend revenue after provision for credit losses	62,850	49,870	44,563
Other operating revenue	283,222	267,523	242,268
Other operating expense	250,994	228,664	218,000
Net direct contribution	95,078	88,729	68,831
Gain (loss) on financial instruments, net	(42)	(204)	(235)
Change in fair value of mortgage servicing rights	0	0	0
Gain (loss) on repossessed assets, net	0	0	0
Corporate expense allocations	42,378	40,357	38,731
Net income before taxes	52,658	48,168	29,865
Federal and state income taxes	20,484	18,737	11,617
Net income	32,174	29,431	18,248
Net income (loss) attributable to non-controlling interests	0	0	0
Net income attributable to BOK Financial Corp. shareholders	32,174	29,431	18,248
Average assets	6,281,127	5,444,483	5,002,515
Corporate, Non-Segment [Member] | Funds Management and Other [Member]
Segment Reporting Information [Line Items]
Net interest and dividend revenue from external sources	135,257	154,011	177,194
Net interest revenue (expense) from internal sources	(8,039)	(233)	(7,689)
Net interest and dividend revenue	127,218	153,778	169,505
Provision for credit losses	27,915	34,897	1,757
Net interest and dividend revenue after provision for credit losses	99,303	118,881	167,748
Other operating revenue	(29,525)	(4,867)	(6,357)
Other operating expense	300,401	261,653	226,685
Net direct contribution	(230,623)	(147,639)	(65,294)
Gain (loss) on financial instruments, net	26,284	4,916	(12,171)
Change in fair value of mortgage servicing rights	2,193	4,853	16,445
Gain (loss) on repossessed assets, net	(1,648)	(1,624)	1,769
Corporate expense allocations	(144,549)	(158,572)	(148,764)
Net income before taxes	(59,245)	19,078	89,513
Federal and state income taxes	(48,407)	(21,103)	7,956
Net income	(10,838)	40,181	81,557
Net income (loss) attributable to non-controlling interests	(387)	3,694	3,044
Net income attributable to BOK Financial Corp. shareholders	(10,451)	36,487	78,513
Average assets	$ 276,277	$ 9,418	$ (771,931)

Fair Value Measurements, Fair V

Fair Value Measurements, Fair Value Of Financial Instruments as Measured On a Recurring Basis (Details) - USD ($) $ in Thousands	Dec. 31, 2016		Dec. 31, 2015		Dec. 31, 2014	Dec. 31, 2013
Assets [Abstract]
Trading securities	$ 337,628		$ 122,404
Available for sale securities	8,676,829		9,042,733
Fair value option securities	77,046		444,217
Mortgage servicing rights	247,073		218,605		$ 171,976	$ 153,333
Derivative contracts, net of cash margin, Assets, Fair Value	689,872		586,270
Liabilities [Abstract]
Derivative contracts, net of cash margin, Liabilities, Fair Value	664,531		581,701
U.S. government agency debentures [Member]
Assets [Abstract]
Trading securities	6,234		61,295
U.S. government agency residential mortgage-backed securities [Member]
Assets [Abstract]
Trading securities	310,067		10,989
Available for sale securities	5,460,386	[1]	5,898,351
Fair value option securities	77,046		444,217
Municipal and other tax-exempt securities [Member]
Assets [Abstract]
Trading securities	14,427		31,901
Available for sale securities	40,993		56,817
Other trading securities [Member]
Assets [Abstract]
Trading securities	6,900		18,219
U.S. Treasury securities [Member]
Assets [Abstract]
Available for sale securities	999		995
Privately issued residential mortgage-backed securities [Member]
Assets [Abstract]
Available for sale securities	115,535		139,118
Commercial mortgage-backed securities guaranteed by U.S. government agencies [Member]
Assets [Abstract]
Available for sale securities	3,017,933		2,905,796
Other debt securities [Member]
Assets [Abstract]
Available for sale securities	4,152		4,151
Perpetual preferred stock [Member]
Assets [Abstract]
Available for sale securities	18,474		19,672
Equity securities and mutual funds [Member]
Assets [Abstract]
Available for sale securities	18,357		17,833
Fair Value, Measurements, Recurring [Member]
Assets [Abstract]
Trading securities	337,628		122,404
Available for sale securities	8,676,829		9,042,733
Residential mortgage loans held for sale	301,897		308,439
Mortgage servicing rights	247,073	[2]	218,605	[3]
Derivative contracts, net of cash margin, Assets, Fair Value	689,872	[4]	586,270	[5]
Liabilities [Abstract]
Derivative contracts, net of cash margin, Liabilities, Fair Value	664,531	[4]	581,701	[5]
Fair Value, Measurements, Recurring [Member] | U.S. government agency debentures [Member]
Assets [Abstract]
Trading securities	6,234		61,295
Fair Value, Measurements, Recurring [Member] | U.S. government agency residential mortgage-backed securities [Member]
Assets [Abstract]
Trading securities	310,067		10,989
Available for sale securities	5,460,386		5,898,351
Fair value option securities	77,046		444,217
Fair Value, Measurements, Recurring [Member] | Municipal and other tax-exempt securities [Member]
Assets [Abstract]
Trading securities	14,427		31,901
Available for sale securities	40,993		56,817
Fair Value, Measurements, Recurring [Member] | Other trading securities [Member]
Assets [Abstract]
Trading securities	6,900		18,219
Fair Value, Measurements, Recurring [Member] | U.S. Treasury securities [Member]
Assets [Abstract]
Available for sale securities	999		995
Fair Value, Measurements, Recurring [Member] | Privately issued residential mortgage-backed securities [Member]
Assets [Abstract]
Available for sale securities	115,535		139,118
Fair Value, Measurements, Recurring [Member] | Commercial mortgage-backed securities guaranteed by U.S. government agencies [Member]
Assets [Abstract]
Available for sale securities	3,017,933		2,905,796
Fair Value, Measurements, Recurring [Member] | Other debt securities [Member]
Assets [Abstract]
Available for sale securities	4,152		4,151
Fair Value, Measurements, Recurring [Member] | Perpetual preferred stock [Member]
Assets [Abstract]
Available for sale securities	18,474		19,672
Fair Value, Measurements, Recurring [Member] | Equity securities and mutual funds [Member]
Assets [Abstract]
Available for sale securities	18,357		17,833
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Assets [Abstract]
Trading securities	0		0
Available for sale securities	4,494		4,260
Residential mortgage loans held for sale	0		0
Mortgage servicing rights	0	[2]	0	[3]
Derivative contracts, net of cash margin, Assets, Fair Value	7,541	[4]	38,530	[5]
Liabilities [Abstract]
Derivative contracts, net of cash margin, Liabilities, Fair Value	6,972	[4]	0	[5]
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | U.S. government agency debentures [Member]
Assets [Abstract]
Trading securities	0		0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | U.S. government agency residential mortgage-backed securities [Member]
Assets [Abstract]
Trading securities	0		0
Available for sale securities	0		0
Fair value option securities	0		0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Municipal and other tax-exempt securities [Member]
Assets [Abstract]
Trading securities	0		0
Available for sale securities	0		0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Other trading securities [Member]
Assets [Abstract]
Trading securities	0		0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | U.S. Treasury securities [Member]
Assets [Abstract]
Available for sale securities	999		995
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Privately issued residential mortgage-backed securities [Member]
Assets [Abstract]
Available for sale securities	0		0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Commercial mortgage-backed securities guaranteed by U.S. government agencies [Member]
Assets [Abstract]
Available for sale securities	0		0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Other debt securities [Member]
Assets [Abstract]
Available for sale securities	0		0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Perpetual preferred stock [Member]
Assets [Abstract]
Available for sale securities	0		0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Equity securities and mutual funds [Member]
Assets [Abstract]
Available for sale securities	3,495		3,265
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Assets [Abstract]
Trading securities	337,628		122,404
Available for sale securities	8,662,394		9,024,712
Residential mortgage loans held for sale	290,280		300,565
Mortgage servicing rights	0	[2]	0	[3]
Derivative contracts, net of cash margin, Assets, Fair Value	682,331	[4]	547,740	[5]
Liabilities [Abstract]
Derivative contracts, net of cash margin, Liabilities, Fair Value	657,559	[4]	581,701	[5]
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | U.S. government agency debentures [Member]
Assets [Abstract]
Trading securities	6,234		61,295
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | U.S. government agency residential mortgage-backed securities [Member]
Assets [Abstract]
Trading securities	310,067		10,989
Available for sale securities	5,460,386		5,898,351
Fair value option securities	77,046		444,217
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Municipal and other tax-exempt securities [Member]
Assets [Abstract]
Trading securities	14,427		31,901
Available for sale securities	35,204		47,207
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Other trading securities [Member]
Assets [Abstract]
Trading securities	6,900		18,219
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | U.S. Treasury securities [Member]
Assets [Abstract]
Available for sale securities	0		0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Privately issued residential mortgage-backed securities [Member]
Assets [Abstract]
Available for sale securities	115,535		139,118
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Commercial mortgage-backed securities guaranteed by U.S. government agencies [Member]
Assets [Abstract]
Available for sale securities	3,017,933		2,905,796
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Other debt securities [Member]
Assets [Abstract]
Available for sale securities	0		0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Perpetual preferred stock [Member]
Assets [Abstract]
Available for sale securities	18,474		19,672
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Equity securities and mutual funds [Member]
Assets [Abstract]
Available for sale securities	14,862		14,568
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Assets [Abstract]
Trading securities	0		0
Available for sale securities	9,941		13,761
Residential mortgage loans held for sale	11,617		7,874
Mortgage servicing rights	247,073	[2]	218,605	[3]
Derivative contracts, net of cash margin, Assets, Fair Value	0	[4]	0	[5]
Liabilities [Abstract]
Derivative contracts, net of cash margin, Liabilities, Fair Value	0	[4]	0	[5]
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | U.S. government agency debentures [Member]
Assets [Abstract]
Trading securities	0		0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | U.S. government agency residential mortgage-backed securities [Member]
Assets [Abstract]
Trading securities	0		0
Available for sale securities	0		0
Fair value option securities	0		0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Municipal and other tax-exempt securities [Member]
Assets [Abstract]
Trading securities	0		0
Available for sale securities	5,789		9,610
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Other trading securities [Member]
Assets [Abstract]
Trading securities	0		0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | U.S. Treasury securities [Member]
Assets [Abstract]
Available for sale securities	0		0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Privately issued residential mortgage-backed securities [Member]
Assets [Abstract]
Available for sale securities	0		0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Commercial mortgage-backed securities guaranteed by U.S. government agencies [Member]
Assets [Abstract]
Available for sale securities	0		0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Other debt securities [Member]
Assets [Abstract]
Available for sale securities	4,152		4,151
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Perpetual preferred stock [Member]
Assets [Abstract]
Available for sale securities	0		0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Equity securities and mutual funds [Member]
Assets [Abstract]
Available for sale securities	$ 0		$ 0
[1]	U.S. government and government sponsored enterprises are not rated by the nationally-recognized rating agencies as these securities are guaranteed by agencies of the U.S. government or government-sponsored enterprises.
[2]	A reconciliation of the beginning and ending fair value of mortgage servicing rights and disclosures of significant assumptions used to determine fair value are presented in Note 7, Mortgage Banking Activities.
[3]	A reconciliation of the beginning and ending fair value of mortgage servicing rights and disclosures of significant assumptions used to determine fair value are presented in Note 7, Mortgage Banking Activities.
[4]	See Note 3 for detail of fair value of derivative contracts by contract type. Derivative contracts in a net asset position that were valued based on quoted prices in active markets or identical instruments (Level 1) are exchange-traded interest rate and energy derivative contracts, net of cash margin. Derivative contracts in a net liability position that were valued using quoted prices in active markets for identical instruments (Level 1) are exchange-traded interest rate, energy and agricultural derivative contracts, net of cash margin.
[5]	See Note 3 for detail of fair value of derivative contracts by contract type. Derivative contracts in a net asset position that were valued based on quoted prices in active markets for identical instruments (Level 1) are exchange-traded energy derivative contracts, net of cash margin. Derivative contracts in a net liability position that were valued using quoted prices in active markets for identical instruments based on quoted prices in active markets for identical instruments (Level 1) are exchange-traded interest rate and agricultural derivative contracts, fully offset by cash margin.

Fair Value Measurements, Measur

Fair Value Measurements, Measured On Recurring Basis Significant Unobservable Inputs (Details) - Fair Value, Measurements, Recurring [Member] - Fair Value, Inputs, Level 3 [Member] - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015
Available for sale securities [Member] | Municipal and other tax-exempt securities [Member]
Fair Value Assets Measured on Recurring Basis Unobservable Reconciliation [Roll Forward]
Balance at beginning of period		$ 9,610	$ 10,093
Transfers to Level 3 from Level 2		0	0
Purchases and capital calls		0	0
Redemptions and distributions		(3,975)	0
Proceeds from sales		0	0
Other comprehensive income (loss)		154	(483)
Balance at end of period		5,789	9,610
Available for sale securities [Member] | Municipal and other tax-exempt securities [Member] | Mortgage banking revenue [Member]
Fair Value Assets Measured on Recurring Basis Unobservable Reconciliation [Roll Forward]
Gain (loss) recognized in earnings		0	0
Available for sale securities [Member] | Other debt securities [Member]
Fair Value Assets Measured on Recurring Basis Unobservable Reconciliation [Roll Forward]
Balance at beginning of period		4,151	4,150
Transfers to Level 3 from Level 2		0	0
Purchases and capital calls		0	0
Redemptions and distributions		0	0
Proceeds from sales		0	0
Other comprehensive income (loss)		1	1
Balance at end of period		4,152	4,151
Available for sale securities [Member] | Other debt securities [Member] | Mortgage banking revenue [Member]
Fair Value Assets Measured on Recurring Basis Unobservable Reconciliation [Roll Forward]
Gain (loss) recognized in earnings		0	0
Residential mortgage loans held for sale [Member]
Fair Value Assets Measured on Recurring Basis Unobservable Reconciliation [Roll Forward]
Balance at beginning of period		7,874	11,856
Transfers to Level 3 from Level 2	[1]	6,631	2,193
Purchases and capital calls		0	0
Redemptions and distributions		0	0
Proceeds from sales		(2,540)	(6,283)
Other comprehensive income (loss)		0	0
Balance at end of period		11,617	7,874
Residential mortgage loans held for sale [Member] | Mortgage banking revenue [Member]
Fair Value Assets Measured on Recurring Basis Unobservable Reconciliation [Roll Forward]
Gain (loss) recognized in earnings		$ (348)	$ 108
[1]	Recurring transfers to Level 3 from Level 2 consist of residential mortgage loans intended for sale to U.S. government agencies that fail to meet conforming standards.

Fair Value Measurements Fair Va

Fair Value Measurements Fair Value Measurements, Financial Instruments Measured On a Recurring Basis, Quantitative Information (Details) - Fair Value, Measurements, Recurring [Member] - Fair Value, Inputs, Level 3 [Member] - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2016		Dec. 31, 2015
Available for sale securities [Member] | Municipal and other tax-exempt securities [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Par Value		$ 6,195		$ 10,370
Amortized Cost		6,163		10,311
Fair Value		$ 5,712		$ 9,610
Valuation Techniques		Discounted cash flows	[1]	Discounted cash flows	[2]
Significant Unobservable Input		Interest rate spread		Interest rate spread
Discount Rate, Minimum		5.91%	[3]	5.47%	[4]
Discount Rate, Maximum		6.21%	[3]	5.77%	[4]
Discount Rate, Weighted Average		6.16%	[3]	5.73%	[4]
Fair Value As Percentage of Par Value or Principal Balance, Minimum	[5]	90.00%		92.34%
Fair Value As Percentage of Par Value or Principal Balance, Maximum	[5]	93.40%		92.93%
Fair Value As Percentage of Par Value or Unpaid Principal Balance, Weighted Average	[5]	92.20%		92.67%
Investment Grade Tax Exempt Securities Yield Spread Over Comparable Securities, Minimum		467		499
Investment Grade Tax Exempt Securities Yield Spread Over Comparable Securities, Maximum		525		541
Available for sale securities [Member] | Other debt securities [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Par Value		$ 4,400		$ 4,400
Amortized Cost		4,400		4,400
Fair Value		$ 4,152		$ 4,151
Valuation Techniques		Discounted cash flows	[1]	Discounted cash flows	[2]
Significant Unobservable Input		Interest rate spread		Interest rate spread
Discount Rate, Minimum		6.01%	[6]	5.80%	[7]
Discount Rate, Maximum		6.26%	[6]	5.92%	[7]
Discount Rate, Weighted Average		6.23%	[6]	5.90%	[7]
Fair Value As Percentage of Par Value or Principal Balance, Minimum		94.34%	[5]	94.33%	[8]
Fair Value As Percentage of Par Value or Principal Balance, Maximum		94.36%	[5]	94.34%	[8]
Fair Value As Percentage of Par Value or Unpaid Principal Balance, Weighted Average		94.36%	[5]	94.34%	[8]
Average Yields On Comparable Short-term Taxable Securities		1.00%		1.00%
Residential mortgage loans held for sale [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Amortized Cost		$ 12,431		$ 8,395
Fair Value		$ 11,617		$ 7,874
Valuation Techniques		Quoted prices of loans sold in securitization transactions, with a liquidity discount applied		Quoted prices of loans sold in securitization transactions, with a liquidity discount applied
Significant Unobservable Input		Liquidity discount applied to the market value of mortgage loans qualifying for sale to U.S. government agencies		Liquidity discount applied to the market value of mortgage loans qualifying for sale to U.S. government agencies
Fair Value As Percentage of Par Value or Principal Balance, Minimum		93.45%		93.79%
Fair Value As Percentage of Par Value or Principal Balance, Maximum		93.45%		93.79%
Fair Value As Percentage of Par Value or Unpaid Principal Balance, Weighted Average		93.45%		93.79%
[1]	Discounted cash flows developed using discount rates primarily based on reference to interest rate spreads for comparable securities of similar duration and credit rating as determined by the nationally-recognized rating agencies, adjusted for lack of trading volume.
[2]	Discounted cash flows developed using discount rates primarily based on reference to interest rate spreads for comparable securities of similar duration and credit rating as determined by the nationally-recognized rating agencies, adjusted for lack of trading volume.
[3]	Interest rate yields used to value investment grade tax-exempt securities represent a spread of 467 to 525 basis points over average yields for comparable tax-exempt securities.
[4]	Interest rate yields used to value investment grade tax-exempt securities represent a spread of 499 to 541 basis points over average yields for comparable tax-exempt securities.
[5]	Represents fair value as a percentage of par value
[6]	Interest rate yields used to value investment grade taxable securities based on comparable short-term taxable securities which are generally yielding approximately 1%.
[7]	Interest rate yields used to value investment grade taxable securities based on comparable short-term taxable securities which are generally yielding less than 1%.
[8]	Represents fair value as a percentage of par value

Fair Value Measurements, Fair95

Fair Value Measurements, Fair Value Measured On a Nonrecurring Basis (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Fair Value, Measurements, Nonrecurring [Member] | Impaired Loans [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Gross charge-offs against allowance for loan losses	$ 7,594	$ 4,042
Net losses and expenses of repossessed assets, net	0	0
Fair Value, Measurements, Nonrecurring [Member] | Real estate and other repossessed assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Gross charge-offs against allowance for loan losses	0	0
Net losses and expenses of repossessed assets, net	2,527	1,820
Fair Value, Measurements, Nonrecurring [Member] | Fair Value, Inputs, Level 1 [Member] | Impaired Loans [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying Value	0	0
Fair Value, Measurements, Nonrecurring [Member] | Fair Value, Inputs, Level 1 [Member] | Real estate and other repossessed assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying Value	0	0
Fair Value, Measurements, Nonrecurring [Member] | Fair Value, Inputs, Level 2 [Member] | Impaired Loans [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying Value	539	252
Fair Value, Measurements, Nonrecurring [Member] | Fair Value, Inputs, Level 2 [Member] | Real estate and other repossessed assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying Value	7,965	13,611
Fair Value, Measurements, Nonrecurring [Member] | Fair Value, Inputs, Level 3 [Member] | Impaired Loans [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying Value	11,295	20,805
Fair Value, Measurements, Nonrecurring [Member] | Fair Value, Inputs, Level 3 [Member] | Real estate and other repossessed assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying Value	2,192	245
Pension Plan [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	41,769	44,190	$ 49,443
Pension Plan [Member] | Fair Value, Measurements, Nonrecurring [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	$ 42,000	$ 44,000

Fair Value Measurements Fair 96

Fair Value Measurements Fair Value Measurement, Measured On Non-Recurring Basis, Signfiicant Unobservable Inputs, Quantitative Information (Details) - Fair Value, Measurements, Nonrecurring [Member] - Fair Value, Inputs, Level 3 [Member] - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2016		Dec. 31, 2015
Impaired Loans [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value		$ 11,295		$ 20,805
Valuation Techniques		Appraised value, as adjusted		Appraised value, as adjusted
Significant Unobservable Input		Recoverable oil and gas reserves, forward-looking commodity prices and estimated operating costs		Broker quotes and management's knowledge of industry and collateral.
Fair Value of Impaired Loans as a Percentage of Unpaid Principal Balance [Abstract]
Fair Value of Impaired Loans as a Percentage of Unpaid Principal Balance, Minimum	[1]	22.00%
Fair Value of Impaired Loans as a Percentage of Unpaid Principal Balance, Maximum	[1]	59.00%
Fair Value of Impaired Loans as a Percentage of Unpaid Principal Balance, Weighted Average	[1]	57.00%
Real estate and other repossessed assets [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value		$ 2,192		$ 245
Valuation Techniques		Appraised value, as adjusted		Appraised value, as adjusted
Significant Unobservable Input		Marketability adjustments off appraised value2	[2]	Marketability adjustments off appraised value1	[3]
Fair Value of Real Estate and Other Repossessed Assets as a Percentage of Appraised Value [Abstract]
Fair Value of Real Estate and Other Repossessed Assets, Percentage of Appraised Value, Minimum		70.00%		66.00%
Fair Value of Real Estate and Other Repossessed Assets, Percentage of Appraised Value, Maximum		87.00%		81.00%
Fair Value of Real Estate and Other Repossessed Assets, Percentage of Appraised Value, Weighted Average		74.00%		74.00%
Fair Value of Real Estate and Other Repossessed Assets, Percentage of Appraised Value, Costs to Sell		10.00%
[1]	Represents fair value as a percentage of the unpaid principal balance.
[2]	Marketability adjustments include consideration of estimated costs to sell which is approximately 10% of the fair value.
[3]	Marketability adjustments include consideration of estimated costs to sell which is approximately 10% of the fair value.

Fair Value Measurements, Financ

Fair Value Measurements, Financial Instruments (Details) - USD ($) $ in Thousands	Dec. 31, 2016		Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Interest-bearing cash and cash equivalents	$ 1,916,651		$ 2,069,900
Trading securities	337,628		122,404
Investment securities	546,145		597,836
Available for sale securities	8,676,829		9,042,733
Fair value option securities	77,046		444,217
Residential mortgage loans held for sale	301,897		308,439
Loans	16,989,660		15,941,154
Allowance for loan losses	(246,159)		(225,524)	$ (189,056)	$ (185,396)
Loans, net of allowance	16,743,501		15,715,630
Mortgage servicing rights	247,073		218,605	171,976	153,333
Derivative contracts, net of cash margin, Assets, Fair Value	689,872		586,270
Time deposits	2,221,800		2,406,064
Subordinated debentures	144,640		226,350
Derivative contracts, net of cash margin, Liabilities, Fair Value	664,531		581,701
Fair Value Assumptions and Methodology for Assets and Liabilities [Abstract]
Specific allocation of allowance for loan losses included in fair value of loans	218,000		195,000
Commercial [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	10,390,824		10,252,531
Allowance for loan losses	(140,213)		(130,334)	(90,875)	(79,180)
Commercial Real Estate [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	3,809,046		3,259,033
Allowance for loan losses	(50,749)		(41,391)	(42,445)	(41,573)
Residential Mortgage [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	1,949,832		1,876,893
Allowance for loan losses	(18,224)		(19,509)	(23,458)	(29,465)
Personal [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	839,958		552,697
Allowance for loan losses	(8,773)		(4,164)	$ (4,233)	$ (6,965)
U.S. government agency debentures [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	6,234		61,295
U.S. government agency residential mortgage-backed securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	310,067		10,989
Available for sale securities	5,460,386	[1]	5,898,351
Fair value option securities	77,046		444,217
Municipal and other tax-exempt securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	14,427		31,901
Investment securities	320,364		365,258
Available for sale securities	40,993		56,817
Other trading securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	6,900		18,219
U.S. Treasury securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale securities	999		995
Privately issued residential mortgage-backed securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale securities	115,535		139,118
Commercial mortgage-backed securities guaranteed by U.S. government agencies [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale securities	3,017,933		2,905,796
Other debt securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities	205,004		205,745
Available for sale securities	4,152		4,151
Perpetual preferred stock [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale securities	18,474		19,672
Equity securities and mutual funds [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale securities	18,357		17,833
Carrying (Reported) Amount, Fair Value Disclosure [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and due from banks	620,846		573,699
Interest-bearing cash and cash equivalents	1,916,651		2,069,900
Trading securities	337,628		122,404
Investment securities	546,145		597,836
Available for sale securities	8,676,829		9,042,733
Residential mortgage loans held for sale	301,897		308,439
Loans	16,989,660		15,941,154
Allowance for loan losses	(246,159)		(225,524)
Loans, net of allowance	16,743,501		15,715,630
Mortgage servicing rights	247,073		218,605
Derivative contracts, net of cash margin, Assets, Fair Value	689,872		586,270
Deposits with no stated maturity	20,526,295		18,682,094
Time deposits	2,221,800		2,406,064
Other borrowed funds	5,572,662		6,051,515
Subordinated debentures	144,640		226,350
Derivative contracts, net of cash margin, Liabilities, Fair Value	664,531		581,701
Carrying (Reported) Amount, Fair Value Disclosure [Member] | Commercial [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	10,390,824		10,252,531
Carrying (Reported) Amount, Fair Value Disclosure [Member] | Commercial Real Estate [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	3,809,046		3,259,033
Carrying (Reported) Amount, Fair Value Disclosure [Member] | Residential Mortgage [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	1,949,832		1,876,893
Carrying (Reported) Amount, Fair Value Disclosure [Member] | Personal [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	839,958		552,697
Carrying (Reported) Amount, Fair Value Disclosure [Member] | U.S. government agency debentures [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	6,234		61,295
Carrying (Reported) Amount, Fair Value Disclosure [Member] | U.S. government agency residential mortgage-backed securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	310,067		10,989
Investment securities	20,777		26,833
Available for sale securities	5,460,386		5,898,351
Fair value option securities	77,046		444,217
Carrying (Reported) Amount, Fair Value Disclosure [Member] | Municipal and other tax-exempt securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	14,427		31,901
Investment securities	320,364		365,258
Available for sale securities	40,993		56,817
Carrying (Reported) Amount, Fair Value Disclosure [Member] | Other trading securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	6,900		18,219
Carrying (Reported) Amount, Fair Value Disclosure [Member] | U.S. Treasury securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale securities	999		995
Carrying (Reported) Amount, Fair Value Disclosure [Member] | Privately issued residential mortgage-backed securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale securities	115,535		139,118
Carrying (Reported) Amount, Fair Value Disclosure [Member] | Commercial mortgage-backed securities guaranteed by U.S. government agencies [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale securities	3,017,933		2,905,796
Carrying (Reported) Amount, Fair Value Disclosure [Member] | Other debt securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities	205,004		205,745
Available for sale securities	4,152		4,151
Carrying (Reported) Amount, Fair Value Disclosure [Member] | Perpetual preferred stock [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale securities	18,474		19,672
Carrying (Reported) Amount, Fair Value Disclosure [Member] | Equity securities and mutual funds [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale securities	18,357		17,833
Estimate of Fair Value, Fair Value Disclosure [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and due from banks	620,846		573,699
Interest-bearing cash and cash equivalents	1,916,651		2,069,900
Trading securities	337,628		122,404
Investment securities	565,493		629,159
Available for sale securities	8,676,829		9,042,733
Residential mortgage loans held for sale	301,897		308,439
Loans	17,178,060		15,739,472
Allowance for loan losses	0		0
Loans, net of allowance	17,178,060		15,739,472
Mortgage servicing rights	247,073		218,605
Derivative contracts, net of cash margin, Assets, Fair Value	689,872		586,270
Deposits with no stated maturity	20,526,295		18,682,094
Time deposits	2,218,303		2,394,562
Other borrowed funds	5,556,327		5,600,932
Subordinated debentures	128,903		223,758
Derivative contracts, net of cash margin, Liabilities, Fair Value	664,531		581,701
Estimate of Fair Value, Fair Value Disclosure [Member] | Commercial [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	10,437,016		10,053,952
Estimate of Fair Value, Fair Value Disclosure [Member] | Commercial Real Estate [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	3,850,981		3,233,476
Estimate of Fair Value, Fair Value Disclosure [Member] | Residential Mortgage [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	2,025,159		1,902,976
Estimate of Fair Value, Fair Value Disclosure [Member] | Personal [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	864,904		549,068
Estimate of Fair Value, Fair Value Disclosure [Member] | U.S. government agency debentures [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	6,234		61,295
Estimate of Fair Value, Fair Value Disclosure [Member] | U.S. government agency residential mortgage-backed securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	310,067		10,989
Investment securities	21,473		27,874
Available for sale securities	5,460,386		5,898,351
Fair value option securities	77,046		444,217
Estimate of Fair Value, Fair Value Disclosure [Member] | Municipal and other tax-exempt securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	14,427		31,901
Investment securities	321,225		368,910
Available for sale securities	40,993		56,817
Estimate of Fair Value, Fair Value Disclosure [Member] | Other trading securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	6,900		18,219
Estimate of Fair Value, Fair Value Disclosure [Member] | U.S. Treasury securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale securities	999		995
Estimate of Fair Value, Fair Value Disclosure [Member] | Privately issued residential mortgage-backed securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale securities	115,535		139,118
Estimate of Fair Value, Fair Value Disclosure [Member] | Commercial mortgage-backed securities guaranteed by U.S. government agencies [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale securities	3,017,933		2,905,796
Estimate of Fair Value, Fair Value Disclosure [Member] | Other debt securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities	222,795		232,375
Available for sale securities	4,152		4,151
Estimate of Fair Value, Fair Value Disclosure [Member] | Perpetual preferred stock [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale securities	18,474		19,672
Estimate of Fair Value, Fair Value Disclosure [Member] | Equity securities and mutual funds [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale securities	18,357		17,833
Fair Value, Inputs, Level 1 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and due from banks	620,846		573,699
Interest-bearing cash and cash equivalents	1,916,651		2,069,900
Trading securities	0		0
Investment securities	0		0
Available for sale securities	4,494		4,260
Residential mortgage loans held for sale	0		0
Loans	0		0
Allowance for loan losses	0		0
Loans, net of allowance	0		0
Mortgage servicing rights	0		0
Derivative contracts, net of cash margin, Assets, Fair Value	7,541		38,530
Deposits with no stated maturity	0		0
Time deposits	0		0
Other borrowed funds	0		0
Subordinated debentures	0		0
Derivative contracts, net of cash margin, Liabilities, Fair Value	6,972		0
Fair Value, Inputs, Level 1 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Commercial [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	0		0
Fair Value, Inputs, Level 1 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Commercial Real Estate [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	0		0
Fair Value, Inputs, Level 1 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Residential Mortgage [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	0		0
Fair Value, Inputs, Level 1 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Personal [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	0		0
Fair Value, Inputs, Level 1 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | U.S. government agency debentures [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	0		0
Fair Value, Inputs, Level 1 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | U.S. government agency residential mortgage-backed securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	0		0
Investment securities	0		0
Available for sale securities	0		0
Fair value option securities	0		0
Fair Value, Inputs, Level 1 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Municipal and other tax-exempt securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	0		0
Investment securities	0		0
Available for sale securities	0		0
Fair Value, Inputs, Level 1 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Other trading securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	0		0
Fair Value, Inputs, Level 1 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | U.S. Treasury securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale securities	999		995
Fair Value, Inputs, Level 1 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Privately issued residential mortgage-backed securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale securities	0		0
Fair Value, Inputs, Level 1 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Commercial mortgage-backed securities guaranteed by U.S. government agencies [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale securities	0		0
Fair Value, Inputs, Level 1 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Other debt securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities	0		0
Available for sale securities	0		0
Fair Value, Inputs, Level 1 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Perpetual preferred stock [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale securities	0		0
Fair Value, Inputs, Level 1 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Equity securities and mutual funds [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale securities	3,495		3,265
Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and due from banks	0		0
Interest-bearing cash and cash equivalents	0		0
Trading securities	337,628		122,404
Investment securities	565,493		629,159
Available for sale securities	8,662,394		9,024,712
Residential mortgage loans held for sale	290,280		300,565
Loans	0		0
Allowance for loan losses	0		0
Loans, net of allowance	0		0
Mortgage servicing rights	0		0
Derivative contracts, net of cash margin, Assets, Fair Value	682,331		547,740
Deposits with no stated maturity	0		0
Time deposits	0		0
Other borrowed funds	0		0
Subordinated debentures	128,903		0
Derivative contracts, net of cash margin, Liabilities, Fair Value	657,559		581,701
Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Commercial [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	0		0
Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Commercial Real Estate [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	0		0
Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Residential Mortgage [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	0		0
Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Personal [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	0		0
Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | U.S. government agency debentures [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	6,234		61,295
Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | U.S. government agency residential mortgage-backed securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	310,067		10,989
Investment securities	21,473		27,874
Available for sale securities	5,460,386		5,898,351
Fair value option securities	77,046		444,217
Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Municipal and other tax-exempt securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	14,427		31,901
Investment securities	321,225		368,910
Available for sale securities	35,204		47,207
Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Other trading securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	6,900		18,219
Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | U.S. Treasury securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale securities	0		0
Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Privately issued residential mortgage-backed securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale securities	115,535		139,118
Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Commercial mortgage-backed securities guaranteed by U.S. government agencies [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale securities	3,017,933		2,905,796
Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Other debt securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities	222,795		232,375
Available for sale securities	0		0
Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Perpetual preferred stock [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale securities	18,474		19,672
Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Equity securities and mutual funds [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale securities	14,862		14,568
Fair Value, Inputs, Level 3 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and due from banks	0		0
Interest-bearing cash and cash equivalents	0		0
Trading securities	0		0
Investment securities	0		0
Available for sale securities	9,941		13,761
Residential mortgage loans held for sale	11,617		7,874
Loans	17,178,060		15,739,472
Allowance for loan losses	0		0
Loans, net of allowance	17,178,060		15,739,472
Mortgage servicing rights	247,073		218,605
Derivative contracts, net of cash margin, Assets, Fair Value	0		0
Deposits with no stated maturity	20,526,295		18,682,094
Time deposits	2,218,303		2,394,562
Other borrowed funds	5,556,327		5,600,932
Subordinated debentures	0		223,758
Derivative contracts, net of cash margin, Liabilities, Fair Value	0		0
Fair Value, Inputs, Level 3 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Commercial [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	10,437,016		10,053,952
Fair Value, Inputs, Level 3 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Commercial Real Estate [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	3,850,981		3,233,476
Fair Value, Inputs, Level 3 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Residential Mortgage [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	2,025,159		1,902,976
Fair Value, Inputs, Level 3 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Personal [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	864,904		549,068
Fair Value, Inputs, Level 3 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | U.S. government agency debentures [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	0		0
Fair Value, Inputs, Level 3 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | U.S. government agency residential mortgage-backed securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	0		0
Investment securities	0		0
Available for sale securities	0		0
Fair value option securities	0		0
Fair Value, Inputs, Level 3 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Municipal and other tax-exempt securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	0		0
Investment securities	0		0
Available for sale securities	5,789		9,610
Fair Value, Inputs, Level 3 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Other trading securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	0		0
Fair Value, Inputs, Level 3 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | U.S. Treasury securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale securities	0		0
Fair Value, Inputs, Level 3 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Privately issued residential mortgage-backed securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale securities	0		0
Fair Value, Inputs, Level 3 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Commercial mortgage-backed securities guaranteed by U.S. government agencies [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale securities	0		0
Fair Value, Inputs, Level 3 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Other debt securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities	0		0
Available for sale securities	4,152		4,151
Fair Value, Inputs, Level 3 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Perpetual preferred stock [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale securities	0		0
Fair Value, Inputs, Level 3 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Equity securities and mutual funds [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale securities	$ 0		$ 0
[1]	U.S. government and government sponsored enterprises are not rated by the nationally-recognized rating agencies as these securities are guaranteed by agencies of the U.S. government or government-sponsored enterprises.

Fair Value Measurements Fair 98

Fair Value Measurements Fair Value Measurements, Financial Instruments, Quantitative Information (Details)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Time Deposits [Member]
Fair Value Inputs, Financial Instruments, Quantitative Information [Line Items]
Contractual Yield, Minimum	0.02%	0.02%
Contractual Yield, Maximum	9.65%	5.50%
Repricing (in years)	1 year 350 days	1 year 285 days
Discount Rate, Minimum	1.57%	1.11%
Discount Rate, Maximum	2.00%	1.57%
Other borrowings [Member]
Fair Value Inputs, Financial Instruments, Quantitative Information [Line Items]
Contractual Yield, Minimum	0.25%	0.25%
Contractual Yield, Maximum	3.50%	3.40%
Repricing (in years)	1 day	1 day
Discount Rate, Minimum	0.55%	0.20%
Discount Rate, Maximum	3.22%	2.89%
Subordinated debentures [Member]
Fair Value Inputs, Financial Instruments, Quantitative Information [Line Items]
Contractual Yield, Minimum	5.38%	1.05%
Contractual Yield, Maximum	5.38%	1.05%
Repricing (in years)	16 years 314 days	1 year 135 days
Discount Rate, Minimum	5.38%	2.12%
Discount Rate, Maximum	5.38%	2.12%
Commercial [Member] | Loans [Member]
Fair Value Inputs, Financial Instruments, Quantitative Information [Line Items]
Contractual Yield, Minimum	0.38%	0.25%
Contractual Yield, Maximum	30.00%	30.00%
Repricing (in years)	256 days	226 days
Discount Rate, Minimum	0.64%	0.52%
Discount Rate, Maximum	4.60%	4.34%
Commercial Real Estate [Member] | Loans [Member]
Fair Value Inputs, Financial Instruments, Quantitative Information [Line Items]
Contractual Yield, Minimum	0.38%	0.38%
Contractual Yield, Maximum	18.00%	18.00%
Repricing (in years)	259 days	266 days
Discount Rate, Minimum	0.94%	0.95%
Discount Rate, Maximum	4.27%	3.93%
Residential Mortgage [Member] | Loans [Member]
Fair Value Inputs, Financial Instruments, Quantitative Information [Line Items]
Contractual Yield, Minimum	1.74%	1.67%
Contractual Yield, Maximum	18.00%	18.00%
Repricing (in years)	2 years 99 days	2 years 153 days
Discount Rate, Minimum	1.71%	0.86%
Discount Rate, Maximum	4.26%	4.25%
Personal [Member] | Loans [Member]
Fair Value Inputs, Financial Instruments, Quantitative Information [Line Items]
Contractual Yield, Minimum	0.25%	0.38%
Contractual Yield, Maximum	21.00%	21.00%
Repricing (in years)	146 days	135 days
Discount Rate, Minimum	1.03%	1.19%
Discount Rate, Maximum	4.59%	4.11%

Parent Company Only Financial99

Parent Company Only Financial Statements Parent Company Only Financial Statements, Condensed Balance Sheet Statement (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Assets [Abstract]
Cash and cash equivalents	$ 2,537,497	$ 2,643,599	$ 2,475,842	$ 1,087,213
Available for sale securities	8,676,829	9,042,733
Other assets	353,017	249,112
Total assets	32,772,281	31,476,128
Liabilities [Abstract]
Other liabilities	182,784	124,284
Subordinated debentures	144,640	226,350
Total liabilities	29,465,924	28,208,489
Shareholders' equity: [Abstract]
Common stock	4	4
Capital surplus	1,006,535	982,009
Retained earnings	2,823,334	2,704,121
Treasury stock	(544,052)	(477,165)
Accumulated other comprehensive income (loss)	(10,967)	21,587	56,673	(25,623)
Total shareholders’ equity	3,274,854	3,230,556
Total liabilities and shareholders’ equity	32,772,281	31,476,128
Parent Company [Member]
Assets [Abstract]
Cash and cash equivalents	163,418	282,169	$ 510,668	$ 561,297
Available for sale securities	19,234	20,150
Investment in bank subsidiaries	3,067,595	2,746,810
Investment in non-bank subsidiaries	177,068	186,271
Other assets	4,865	1,534
Total assets	3,432,180	3,236,934
Liabilities [Abstract]
Other liabilities	5,469	6,378
Other borrowings – Trust preferred debt	7,217	0
Subordinated debentures	144,640	0
Total liabilities	157,326	6,378
Shareholders' equity: [Abstract]
Common stock	4	4
Capital surplus	1,006,535	982,009
Retained earnings	2,823,334	2,704,121
Treasury stock	(544,052)	(477,165)
Accumulated other comprehensive income (loss)	(10,967)	21,587
Total shareholders’ equity	3,274,854	3,230,556
Total liabilities and shareholders’ equity	$ 3,432,180	$ 3,236,934

Parent Company Only Financia100

Parent Company Only Financial Statements Parent Company Only Financial Statements, Condensed Income Statements (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Condensed Income Statements, Captions [Line Items]
Other revenue	$ 51,029	$ 49,883	$ 47,537
Interest expense	81,889	63,474	67,045
Charitable contributions to BOKF Foundation	2,000	796	4,267
Professional fees and services	56,783	40,123	44,440
Other operating expense	1,017,590	896,191	847,522
Federal and state income taxes	106,377	139,384	144,151
Net income attributable to BOK Financial Corp. shareholders	232,668	288,565	292,435
Parent Company [Member]
Condensed Income Statements, Captions [Line Items]
Dividends, interest and fees received from bank subsidiaries	15,237	150,308	75,412
Dividends, interest and fees received from non-bank subsidiaries	25,923	0	0
Other revenue	1,612	1,279	1,572
Total revenue	42,772	151,587	76,984
Interest expense	4,182	131	293
Charitable contributions to BOKF Foundation	0	0	2,420
Professional fees and services	395	378	600
Other operating expense	1,583	1,864	1,556
Total expense	6,160	2,373	4,869
Income before taxes and equity in undistributed income of subsidiaries	36,612	149,214	72,115
Federal and state income taxes	(1,920)	(375)	(1,702)
Income before equity in undistributed income of subsidiaries	38,532	149,589	73,817
Equity in undistributed income of bank subsidiaries	216,120	134,045	214,435
Equity in undistributed income of non-bank subsidiaries	(21,984)	4,931	4,183
Net income attributable to BOK Financial Corp. shareholders	$ 232,668	$ 288,565	$ 292,435

Parent Company Only Financia101

Parent Company Only Financial Statements Parent Company Only Financial Statements, Condensed Cash Flow Statement (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Cash Flows From Operating Activities: [Abstract]
Net income	$ 232,281	$ 292,259	$ 295,479
Adjustments to reconcile net income to net cash provided by (used in) operating activities: [Abstract]
Tax effect from equity compensation, net	(1,505)	(925)	(8,258)
Change in other assets	(49,565)	(29,548)	68,821
Change in other liabilities	(11,413)	15,756	1,007
Net cash provided by operating activities	(93,454)	295,010	(36,630)
Cash Flows From Investing Activities: [Abstract]
Proceeds from sales of available for sale securities	899,381	1,600,380	2,664,740
Acquisitions, net of cash acquired	56,017	(18,098)	(21,898)
Net cash used in investing activities	(286,007)	(2,001,304)	(434,020)
Cash Flows From Financing Activities: [Abstract]
Issuance of subordinated debentures, net of issuance costs	144,615	0	0
Issuance of common and treasury stock, net	12,455	6,711	4,472
Tax effect from equity compensation, net	1,505	925	8,258
Dividends paid	(113,455)	(115,281)	(111,026)
Repurchase of common stock	(66,792)	(229,540)	(12,337)
Net cash used in financing activities	273,359	1,874,051	1,859,279
Net decrease in cash and cash equivalents	(106,102)	167,757	1,388,629
Cash and cash equivalents at beginning of period	2,643,599	2,475,842	1,087,213
Cash and cash equivalents at end of period	2,537,497	2,643,599	2,475,842
Cash paid for interest	82,876	66,091	65,721
Issuance of shares in settlement of deferred compensation, net			8,352
Parent Company [Member]
Cash Flows From Operating Activities: [Abstract]
Net income	232,668	288,565	292,435
Adjustments to reconcile net income to net cash provided by (used in) operating activities: [Abstract]
Equity in undistributed income of bank subsidiaries	(216,120)	(134,045)	(214,435)
Equity in undistributed income of non-bank subsidiaries	21,984	(4,931)	(4,183)
Tax effect from equity compensation, net	(1,505)	(925)	(8,258)
Change in other assets	(2,933)	49	8,726
Change in other liabilities	(1,285)	(2,818)	1,055
Net cash provided by operating activities	32,809	145,895	75,340
Cash Flows From Investing Activities: [Abstract]
Proceeds from sales of available for sale securities	1,632	4,760	0
Investment in subsidiaries	(26,000)	(41,969)	(15,336)
Acquisitions, net of cash acquired	(105,520)	0	0
Net cash used in investing activities	(129,888)	(37,209)	(15,336)
Cash Flows From Financing Activities: [Abstract]
Issuance of subordinated debentures, net of issuance costs	144,615	0	0
Issuance of common and treasury stock, net	12,455	6,711	4,472
Tax effect from equity compensation, net	1,505	925	8,258
Dividends paid	(113,455)	(115,281)	(111,026)
Repurchase of common stock	(66,792)	(229,540)	(12,337)
Net cash used in financing activities	(21,672)	(337,185)	(110,633)
Net decrease in cash and cash equivalents	(118,751)	(228,499)	(50,629)
Cash and cash equivalents at beginning of period	282,169	510,668	561,297
Cash and cash equivalents at end of period	163,418	282,169	510,668
Cash paid for interest	4,127	131	293
Issuance of shares in settlement of deferred compensation, net	$ 0	$ 0	$ 8,352