BOK Financial (BOKF) 10-Q 28 Jul 17 2017 Q2 Quarterly report Financial data

Document And Entity Information

Document And Entity Information	6 Months Ended
	Jun. 30, 2017USD ($)shares
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 | $	$ 2,096,658,923
Entity Common Stock, Shares Outstanding | shares	65,416,403
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	Q2
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2017

Consolidated Statements of Earn

Consolidated Statements of Earnings (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Interest revenue [Abstract]
Loans	$ 168,952	$ 141,560	$ 329,847	$ 280,672
Residential mortgage loans held for sale	2,386	3,508	4,222	6,208
Trading securities	3,339	616	8,522	1,140
Investment securities	4,005	4,217	8,176	8,604
Available for sale securities	43,363	43,872	86,735	89,339
Fair value option securities	3,539	2,062	5,919	4,651
Restricted equity securities	4,399	3,863	8,708	8,174
Interest-bearing cash and cash equivalents	5,198	2,569	9,442	5,275
Total interest revenue	235,181	202,267	461,571	404,063
Interest expense [Abstract]
Deposits	12,622	9,997	23,976	20,539
Borrowed funds	15,352	8,780	27,181	16,752
Subordinated debentures	2,003	878	4,028	1,588
Total interest expense	29,977	19,655	55,185	38,879
Net interest revenue	205,204	182,612	406,386	365,184
Provision for credit losses	0	20,000	0	55,000
Net interest revenue after provision for credit losses	205,204	162,612	406,386	310,184
Other operating revenue [Abstract]
Brokerage and trading revenue	31,764	39,530	65,387	71,871
Transaction card revenue	35,296	34,950	67,423	67,304
Fiduciary and asset management revenue	41,808	34,813	80,439	66,869
Deposit service charges and fees	23,354	22,618	46,384	45,160
Mortgage banking revenue	30,276	34,884	55,467	66,984
Other revenue	14,984	13,352	26,736	25,256
Total fees and commissions	177,482	180,147	341,836	343,444
Other gains, net	6,108	1,307	9,735	2,867
Gain (loss) on derivatives, net	3,241	10,766	2,791	17,904
Gain (loss) on fair value option securities, net	1,984	4,279	844	13,722
Change in fair value of mortgage servicing rights	(6,943)	(16,283)	(5,087)	(44,271)
Gain on available for sale securities, net	380	5,326	2,429	9,290
Total other operating revenue	182,252	185,542	352,548	342,956
Other operating expense [Abstract]
Personnel	143,744	139,213	280,169	272,775
Business promotion	7,738	6,703	14,455	12,399
Professional fees and services	12,419	14,158	23,836	25,917
Net occupancy and equipment	21,125	19,677	42,749	38,443
Insurance	689	7,129	7,093	14,394
Data processing and communications	36,330	32,802	71,232	64,819
Printing, postage and supplies	4,140	3,889	7,991	7,796
Net losses (gains) and operating expenses of repossessed assets	2,267	1,588	3,276	2,658
Amortization of intangible assets	1,803	2,624	3,605	3,783
Mortgage banking costs	12,072	15,746	25,075	28,076
Other expense	8,558	7,856	16,115	22,895
Total other operating expense	250,885	251,385	495,596	493,955
Net income before taxes	136,571	96,769	263,338	159,185
Federal and state income taxes	47,705	30,497	85,808	51,925
Net income	88,866	66,272	177,530	107,260
Net income (loss) attributable to non-controlling interests	719	471	1,027	(1,105)
Net income attributable to BOK Financial Corporation shareholders	$ 88,147	$ 65,801	$ 176,503	$ 108,365
Earnings per share: [Abstract]
Basic	$ 1.35	$ 1	$ 2.70	$ 1.64
Diluted	$ 1.35	$ 1	$ 2.69	$ 1.64
Average shares used in computation: [Abstract]
Basic	64,729,752	65,245,887	64,722,744	65,271,214
Diluted	64,793,134	65,302,926	64,788,322	65,317,177
Dividends declared per share	$ 0.44	$ 0.43	$ 0.88	$ 0.86

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017		Jun. 30, 2016
Statement of Comprehensive Income [Abstract]
Net income	$ 88,866	$ 66,272	$ 177,530		$ 107,260
Other comprehensive income before income taxes:
Net change in unrealized gain (loss)	21,958	45,475	33,369		166,566
Reclassification adjustments included in earnings:
Interest revenue, Investment securities, Taxable securities	0	(43)	0		(112)
Gain on available for sale securities, net	(380)	(5,326)	(2,429)		(9,290)
Other comprehensive income before income taxes	21,578	40,106	30,940		157,164
Federal and state income taxes	8,393	15,583	12,009	[1]	61,119	[1]
Other comprehensive income, net of income taxes	13,185	24,523	18,931		96,045
Comprehensive income	102,051	90,795	196,461		203,305
Comprehensive income (loss) attributable to non-controlling interests	719	471	1,027		(1,105)
Comprehensive income attributable to BOK Financial Corp. shareholders	$ 101,332	$ 90,324	$ 195,434		$ 204,410
[1]	Calculated using a 39 percent effective tax rate.

Consolidated Balance Sheets (Un

Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016	Jun. 30, 2016
Assets [Abstract]
Cash and due from banks	$ 561,587	$ 620,846	$ 498,713
Interest-bearing cash and cash equivalents	2,078,831	1,916,651	1,907,838
Trading securities	441,414	337,628	211,622
Investment securities	490,426	546,145	560,711
Available for sale securities	8,341,041	8,676,829	8,830,689
Fair value option securities	445,169	77,046	263,265
Restricted equity securities	311,033	307,240	319,639
Residential mortgage loans held for sale	287,259	301,897	430,728
Loans	17,183,645	16,989,660	16,406,749
Allowance for loan losses	(250,061)	(246,159)	(243,259)
Loans, net of allowance	16,933,584	16,743,501	16,163,490
Premises and equipment, net	321,038	325,849	315,199
Receivables	295,042	772,952	173,638
Goodwill	446,697	448,899	382,739
Intangible assets, net	40,755	46,931	43,372
Mortgage servicing rights	245,239	247,073	190,747
Real estate and other repossessed assets, net of allowance	39,436	44,287	24,054
Derivative contracts, net	280,289	689,872	883,673
Cash surrender value of bank-owned life insurance	312,774	308,430	307,860
Receivable on unsettled securities sales	33,177	7,188	142,820
Other assets	358,741	353,017	319,653
Total assets	32,263,532	32,772,281	31,970,450
Deposits [Abstract]
Noninterest-bearing demand deposits	9,568,895	9,235,720	8,424,609
Interest-bearing deposits: [Abstract]
Transaction	10,087,139	10,865,105	9,668,869
Savings	464,318	425,470	419,262
Time	2,196,122	2,221,800	2,247,061
Total deposits	22,316,474	22,748,095	20,759,801
Funds purchased	67,990	57,929	56,780
Repurchase agreements	396,333	668,661	472,683
Other borrowings	5,232,343	4,846,072	5,830,736
Subordinated debentures	144,658	144,640	371,812
Accrued interest, taxes and expense	133,198	146,704	197,742
Derivative contracts, net	285,819	664,531	719,159
Due on unsettled securities purchases	32,636	6,508	11,757
Other liabilities	204,536	182,784	147,242
Total liabilities	28,813,987	29,465,924	28,567,712
Shareholders' equity: [Abstract]
Common stock	4	4	4
Capital surplus	1,017,495	1,006,535	990,106
Retained earnings	2,942,447	2,823,334	2,755,766
Treasury stock	(545,441)	(544,052)	(494,675)
Accumulated other comprehensive income (loss)	7,964	(10,967)	117,632
Total shareholders’ equity	3,422,469	3,274,854	3,368,833
Non-controlling interests	27,076	31,503	33,905
Total equity	3,449,545	3,306,357	3,402,738
Total liabilities and equity	$ 32,263,532	$ 32,772,281	$ 31,970,450

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) (Unaudited) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016	Jun. 30, 2016
Investment securities [Abstract]
Investment Securities, fair value	$ 515,675	$ 565,493	$ 599,062
Allowance for real estate and other repossessed assets - Accounts 1953055, 1953056, 1953555	$ 8,576	$ 9,562	$ 9,448
Shareholders' equity: [Abstract]
Common stock, par value (in dollars per share)	$ 0.00006	$ 0.00006	$ 0.00006
Common stock, shares authorized (in shares)	2,500,000,000	2,500,000,000	2,500,000,000
Common stock, shares issued (in shares)	75,089,152	74,993,407	74,817,155
Common stock, shares outstanding (in shares)	75,089,152	74,993,407	74,817,155
Treasury stock, shares at cost (in shares)	9,672,749	9,655,975	8,950,838

Consolidated Statements of Chan

Consolidated Statements of Changes in Equity (Unaudited) - 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, 2015		74,530			8,636
Balance, beginning 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 (loss)	107,260			108,365			108,365	(1,105)
Other comprehensive income	96,045					96,045	96,045
Repurchase of common stock (in shares)					305
Repurchase of common stock	(17,770)				$ (17,770)		(17,770)
Stock options exercised (in shares)		39
Stock options exercised	2,016		2,016				2,016
Non-vested shares awarded, net (in shares)		248
Vesting of non-vested shares (in shares)					10
Vesting of non-vested shares	(260)				$ 260		(260)
Tax effect from equity compensation, net	351		351				351
Share-based compensation	5,730		5,730				5,730
Cash dividends on common stock	(56,720)			(56,720)			(56,720)
Capital calls and distributions, net	(2,073)							(2,073)
Balance, end of period (in shares) at Jun. 30, 2016		74,817			8,951
Balance, end of period at Jun. 30, 2016	3,402,738	$ 4	990,106	2,755,766	$ (494,675)	117,632	3,368,833	33,905
Balance, beginning of period (in shares) at Dec. 31, 2016		74,993			9,656
Balance, beginning 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
Net income (loss)	177,530			176,503			176,503	1,027
Other comprehensive income	18,931					18,931	18,931
Stock options exercised (in shares)		41
Stock options exercised	1,977		1,977				1,977
Non-vested shares awarded, net (in shares)		55
Vesting of non-vested shares (in shares)					17
Vesting of non-vested shares	(1,389)				$ (1,389)		(1,389)
Share-based compensation	8,983		8,983				8,983
Cash dividends on common stock	(57,390)			(57,390)			(57,390)
Capital calls and distributions, net	(5,454)							(5,454)
Balance, end of period (in shares) at Jun. 30, 2017		75,089			9,673
Balance, end of period at Jun. 30, 2017	$ 3,449,545	$ 4	$ 1,017,495	$ 2,942,447	$ (545,441)	$ 7,964	$ 3,422,469	$ 27,076

Consolidated Statements of Cash

Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Cash Flows From Operating Activities: [Abstract]
Net income	$ 177,530	$ 107,260
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for credit losses	0	55,000
Change in fair value of mortgage servicing rights due to market changes	5,087	44,271
Change in the fair value of mortgage servicing rights due to loan runoff	16,261	17,942
Net unrealized gains from derivative contracts	(5,928)	(15,459)
Share-based compensation	8,983	5,730
Depreciation and amortization	25,864	23,532
Net amortization of securities discounts and premiums	15,377	21,814
Net realized gains on financial instruments and other net gains	(4,351)	(9,787)
Net gain on mortgage loans held for sale	(25,229)	(37,151)
Mortgage loans originated for sale	(1,613,997)	(3,062,859)
Proceeds from sale of mortgage loans held for sale	1,651,018	2,981,973
Capitalized mortgage servicing rights	(19,514)	(34,355)
Change in trading and fair value option securities	(472,682)	90,484
Change in receivables	479,774	(9,698)
Change in other assets	(17,548)	(4,740)
Change in accrued interest, taxes and expense	(19,703)	20,299
Change in other liabilities	27,420	(8,854)
Net cash provided by operating activities	228,362	185,402
Cash Flows From Investing Activities: [Abstract]
Proceeds from maturities or redemptions of investment securities	71,654	52,463
Proceeds from maturities or redemptions of available for sale securities	899,096	721,432
Purchases of investment securities	(18,802)	(18,599)
Purchases of available for sale securities	(1,242,070)	(1,155,261)
Proceeds from sales of available for sale securities	700,412	795,140
Change in amount receivable on unsettled securities transactions	(25,989)	(102,627)
Loans originated, net of principal collected	(159,924)	(481,085)
Net payments on derivative asset contracts	420,996	(204,041)
Acquisitions, net of cash acquired	0	(7,700)
Proceeds from disposition of assets	127,699	78,629
Purchases of assets	(106,362)	(107,241)
Net cash provided by investing activities	666,710	(428,890)
Cash Flows From Financing Activities: [Abstract]
Net change in demand deposits, transaction deposits and savings accounts	(405,943)	(169,354)
Net change in time deposits	(25,678)	(159,003)
Net change in other borrowed funds	64,833	259,359
Issuance of subordinated debentures	0	145,390
Net proceeds on derivative liability contracts	(422,016)	196,225
Net change in derivative margin accounts	27,327	(188,823)
Change in amount due on unsettled security transactions	26,128	(5,140)
Issuance of common and treasury stock, net	588	2,276
Repurchase of common stock	0	17,770
Dividends paid	(57,390)	(56,720)
Net cash provided by (used in) financing activities	(792,151)	6,440
Net increase (decrease) in cash and cash equivalents	102,921	(237,048)
Cash and cash equivalents at beginning of period	2,537,497	2,643,599
Cash and cash equivalents at end of period	2,640,418	2,406,551
Supplemental Cash Flow Information: [Abstract]
Cash paid for interest	54,881	40,213
Cash paid for taxes	60,654	14,671
Net loans and bank premises transferred to repossessed real estate and other assets	2,049	5,372
Residential mortgage loans guaranteed by U.S. government agencies that became eligible for repurchase during the period	59,171	49,325
Conveyance of other real estate owned guaranteed by U.S. government agencies	$ 22,602	$ 29,512

Significant Accounting Policies

Significant Accounting Policies	6 Months Ended
	Jun. 30, 2017
Accounting Policies [Abstract]
Significant Accounting Policies [Text Block]	Significant Accounting Policies Basis of Presentation The accompanying unaudited consolidated financial statements of BOK Financial Corporation (“BOK Financial” or “the Company”) have been prepared in accordance with accounting principles for interim financial information generally accepted in the United States and with the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the information and footnotes required by generally accepted accounting principles for complete financial statements. In the opinion of management, all adjustments (consisting of normal recurring accruals) considered necessary for a fair presentation have been included. The unaudited consolidated financial statements include accounts of BOK Financial and its subsidiaries, principally BOKF, NA (“the Bank”), BOK Financial Securities, Inc., The Milestone Group, Inc. and Cavanal Hill Investment Management Inc. Operating divisions of the Bank include Bank of Albuquerque, Bank of Arizona, Bank of Arkansas, Bank of Oklahoma, Bank of Texas, Colorado State Bank and Trust, Mobank, BOK Financial Mortgage and the TransFund electronic funds network. Certain reclassifications have been made to conform to the current period presentation. The financial information should be read in conjunction with BOK Financial’s 2016 Form 10-K filed with the Securities and Exchange Commission, which contains audited financial statements. Amounts presented as of December 31, 2016 have been derived from the audited financial statements included in BOK Financial’s 2016 Form 10-K but do not include all of the information and footnotes required by generally accepted accounting principles for complete financial statements. Operating results for the six -month period ended June 30, 2017 are not necessarily indicative of the results that may be expected for the year ending December 31, 2017 . Newly Adopted and Pending Accounting Policies 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 commissions 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 represents 19% of gross revenue and 43% of fees and commissions revenue for the first half of 2017. Timing of revenue recognition and gross versus net presentation may be affected. Management will 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 is evaluating the impact the adoption of ASU 2016-08 will have on the Company's financial statements along with ASU 2014-09. 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 over the recognition and measurement of financial assets and liabilities. The update 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. At June 30, 2017 , the Company had $3.2 million of unrealized gains included in accumulated 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 lease assets and 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 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. 2016-09, 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 became effective for annual reporting periods beginning after December 15, 2016, including interim periods within those annual reporting periods. Implementation of ASU 2016-09 decreased tax expense $2.3 million in the first six months of 2017. 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 in order to provide more timely recording of credit losses on loans and other financial instruments. The ASU adds 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 a 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 guidance in ASC 230 on the classification of certain cash receipts and payments in the statement of cash flows. The amendments address eight cash flow issues. ASU 2016-15 is effective for the Company for interim and annual reporting periods beginning after December 15, 2017. 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.

Securities

Securities	6 Months Ended
	Jun. 30, 2017
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): June 30, 2017 December 31, 2016 June 30, 2016 Fair Value Net Unrealized Gain (Loss) Fair Value Net Unrealized Gain (Loss) Fair Value Net Unrealized Gain (Loss) U.S. government agency debentures $ 20,954 $ (9 ) $ 6,234 $ (4 ) $ 18,909 $ (8 ) U.S. government agency residential mortgage-backed securities 365,171 (1,032 ) 310,067 635 122,306 363 Municipal and other tax-exempt securities 45,444 230 14,427 50 52,721 262 Other trading securities 9,845 (175 ) 6,900 57 17,686 169 Total trading securities $ 441,414 $ (986 ) $ 337,628 $ 738 $ 211,622 $ 786 Investment Securities The amortized cost and fair values of investment securities are as follows (in thousands): June 30, 2017 Amortized Fair Gross Unrealized 1 Cost Value Gain Loss Municipal and other tax-exempt $ 267,375 $ 270,531 $ 3,384 $ (228 ) U.S. government agency residential mortgage-backed securities – Other 18,035 18,642 668 (61 ) Other debt securities 205,016 226,502 22,040 (554 ) Total investment securities $ 490,426 $ 515,675 $ 26,092 $ (843 ) 1 Gross unrealized gains and losses are not recognized in Accumulated Other Comprehensive Income "AOCI" in the Consolidated Balance Sheets. December 31, 2016 Amortized Fair Gross Unrealized 1 Cost Value Gain Loss Municipal and other tax-exempt $ 320,364 $ 321,225 $ 2,272 $ (1,411 ) U.S. government agency residential mortgage-backed securities – Other 20,777 21,473 767 (71 ) Other debt securities 205,004 222,795 18,115 (324 ) Total investment securities $ 546,145 $ 565,493 $ 21,154 $ (1,806 ) 1 Gross unrealized gains and losses are not recognized in AOCI in the Consolidated Balance Sheets. June 30, 2016 Amortized Fair Gross Unrealized 1 Cost Value Gain Loss Municipal and other tax-exempt $ 334,551 $ 340,700 $ 6,234 $ (85 ) U.S. government agency residential mortgage-backed securities – Other 23,750 25,233 1,483 — Other debt securities 202,410 233,129 30,723 (4 ) Total investment securities $ 560,711 $ 599,062 $ 38,440 $ (89 ) 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 June 30, 2017 , 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: Amortized cost $ 90,415 $ 122,560 $ 10,739 $ 43,661 $ 267,375 3.48 Fair value 90,436 122,914 11,220 45,961 270,531 Nominal yield¹ 1.66 % 2.12 % 4.88 % 5.05 % 2.55 % Other debt securities: Amortized cost 14,286 45,638 130,279 14,813 205,016 6.59 Fair value 14,482 48,973 148,415 14,632 226,502 Nominal yield 3.84 % 4.95 % 5.75 % 4.46 % 5.35 % Total fixed maturity securities: Amortized cost $ 104,701 $ 168,198 $ 141,018 $ 58,474 $ 472,391 4.83 Fair value 104,918 171,887 159,635 60,593 497,033 Nominal yield 1.95 % 2.89 % 5.69 % 4.90 % 3.77 % Residential mortgage-backed securities: Amortized cost $ 18,035 ³ Fair value 18,642 Nominal yield 4 2.76 % Total investment securities: Amortized cost $ 490,426 Fair value 515,675 Nominal yield 3.73 % 1 Calculated on a taxable equivalent basis using a 39 percent 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): June 30, 2017 Amortized Fair Gross Unrealized 1 Cost Value Gain Loss OTTI ² U.S. Treasury $ 1,000 $ 998 $ — $ (2 ) $ — Municipal and other tax-exempt 32,885 32,765 293 (413 ) — Residential mortgage-backed securities: U. S. government agencies: FNMA 3,005,920 3,008,531 24,213 (21,602 ) — FHLMC 1,412,376 1,412,472 7,785 (7,689 ) — GNMA 938,086 936,365 3,641 (5,362 ) — Other 25,000 25,009 52 (43 ) — Total U.S. government agencies 5,381,382 5,382,377 35,691 (34,696 ) — Private issue: Alt-A loans 38,334 46,903 8,569 — — Jumbo-A loans 48,322 56,480 8,158 — — Total private issue 86,656 103,383 16,727 — — Total residential mortgage-backed securities 5,468,038 5,485,760 52,418 (34,696 ) — Commercial mortgage-backed securities guaranteed by U.S. government agencies 2,788,543 2,782,070 7,804 (14,277 ) — Other debt securities 4,400 4,152 — (248 ) — Perpetual preferred stock 12,562 16,568 4,006 — — Equity securities and mutual funds 17,572 18,728 1,219 (63 ) — Total available for sale securities $ 8,325,000 $ 8,341,041 $ 65,740 $ (49,699 ) $ — 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, 2016 Amortized Fair Gross Unrealized¹ Cost Value Gain Loss OTTI ² U.S. Treasury $ 1,000 $ 999 $ — $ (1 ) $ — Municipal and other tax-exempt 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. June 30, 2016 Amortized Fair Gross Unrealized 1 Cost Value Gain Loss OTTI ² U.S. Treasury $ 1,000 $ 1,004 $ 4 $ — $ — Municipal and other tax-exempt 50,170 50,262 805 (713 ) — Residential mortgage-backed securities: U. S. government agencies: FNMA 2,908,698 2,988,974 80,549 (273 ) — FHLMC 1,746,661 1,785,332 38,869 (198 ) — GNMA 921,928 925,962 4,646 (612 ) — Total U.S. government agencies 5,577,287 5,700,268 124,064 (1,083 ) — Private issue: Alt-A loans 49,522 54,536 5,461 — (447 ) Jumbo-A loans 65,787 71,777 6,355 (36 ) (329 ) Total private issue 115,309 126,313 11,816 (36 ) (776 ) Total residential mortgage-backed securities 5,692,596 5,826,581 135,880 (1,119 ) (776 ) Commercial mortgage-backed securities guaranteed by U.S. government agencies 2,854,306 2,911,946 57,762 (122 ) — Other debt securities 4,400 4,151 — (249 ) — Perpetual preferred stock 15,562 17,931 2,369 — — Equity securities and mutual funds 17,270 18,814 1,558 (14 ) — Total available for sale securities $ 8,635,304 $ 8,830,689 $ 198,378 $ (2,217 ) $ (776 ) 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 June 30, 2017 , 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. Treasuries: Amortized cost $ 1,000 $ — $ — $ — $ 1,000 0.55 Fair value 998 — — — 998 Nominal yield 0.87 % — % — % — % 0.87 % Municipal and other tax-exempt: Amortized cost $ 8,981 $ 6,380 $ 1,028 $ 16,496 $ 32,885 8.87 Fair value 9,021 6,497 1,081 16,166 32,765 Nominal yield¹ 4.24 % 3.91 % 6.72 % 2.28 % 6 3.27 % Commercial mortgage-backed securities: Amortized cost $ 58,263 $ 880,459 $ 1,571,735 $ 278,086 $ 2,788,543 6.98 Fair value 58,147 879,286 1,568,732 275,905 2,782,070 Nominal yield 1.20 % 1.83 % 1.84 % 1.88 % 1.82 % Other debt securities: Amortized cost $ — $ — $ — $ 4,400 $ 4,400 30.16 Fair value — — — 4,152 4,152 Nominal yield — % — % — % 1.71 % 6 1.71 % Total fixed maturity securities: Amortized cost $ 68,244 $ 886,839 $ 1,572,763 $ 298,982 $ 2,826,828 7.03 Fair value 68,166 885,783 1,569,813 296,223 2,819,985 Nominal yield 1.60 % 1.85 % 1.85 % 1.90 % 1.83 % Residential mortgage-backed securities: Amortized cost $ 5,468,038 2 Fair value 5,485,760 Nominal yield 4 1.94 % Equity securities and mutual funds: Amortized cost $ 30,134 ³ Fair value 35,296 Nominal yield — % Total available-for-sale securities: Amortized cost $ 8,325,000 Fair value 8,341,041 Nominal yield 1.90 % 1 Calculated on a taxable equivalent basis using a 39 percent effective tax rate. 2 The average expected lives of mortgage-backed securities were 3.9 years 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): Three Months Ended Six Months Ended 2017 2016 2017 2016 Proceeds $ 460,402 $ 325,758 $ 700,412 $ 795,140 Gross realized gains 2,763 5,326 4,855 9,290 Gross realized losses (2,383 ) — (2,426 ) — Related federal and state income tax expense 148 2,072 945 3,614 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): June 30, 2017 Dec. 31, 2016 June 30, 2016 Investment: Amortized cost $ 251,684 $ 322,208 $ 287,166 Fair value 255,097 323,808 293,625 Available for sale: Amortized cost 6,327,666 7,353,116 7,502,361 Fair value 6,317,623 7,327,470 7,657,916 The secured parties do not have the right to sell or repledge these securities. Temporarily Impaired Securities as of June 30, 2017 (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 82 $ 111,078 $ 149 $ 3,000 $ 79 $ 114,078 $ 228 U.S. government agency residential mortgage-backed securities – Other 1 3,810 61 — — 3,810 61 Other debt securities 22 8,384 554 — — 8,384 554 Total investment securities 105 $ 123,272 $ 764 $ 3,000 $ 79 $ 126,272 $ 843 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 1 $ 997 $ 2 $ — $ — $ 997 $ 2 Municipal and other tax-exempt 13 $ 1,957 $ 1 $ 4,655 $ 412 $ 6,612 $ 413 Residential mortgage-backed securities: U. S. government agencies: FNMA 75 1,381,687 20,288 87,371 1,314 1,469,058 21,602 FHLMC 42 731,853 7,213 16,388 476 748,241 7,689 GNMA 21 291,806 3,766 76,605 1,596 368,411 5,362 Other 1 19,957 43 — — 19,957 43 Total U.S. government agencies 139 2,425,303 31,310 180,364 3,386 2,605,667 34,696 Private issue: Alt-A loans — — — — — — — Jumbo-A loans — — — — — — — Total private issue — — — — — — — Total residential mortgage-backed securities 139 2,425,303 31,310 180,364 3,386 2,605,667 34,696 Commercial mortgage-backed securities guaranteed by U.S. government agencies 121 1,388,406 12,690 78,828 1,587 1,467,234 14,277 Other debt securities 2 — — 4,152 248 4,152 248 Perpetual preferred stocks — — — — — — — Equity securities and mutual funds 91 1,668 22 887 41 2,555 63 Total available for sale securities 367 $ 3,818,331 $ 44,025 $ 268,886 $ 5,674 $ 4,087,217 $ 49,699 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 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 1 $ 999 $ 1 $ — $ — $ 999 $ 1 Municipal and other tax-exempt 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. government 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 stocks — — — — — — — 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 June 30, 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 19 $ 11,915 $ 20 $ 4,378 $ 65 $ 16,293 $ 85 U.S. government agency residential mortgage-backed securities – Other — — — — — — — Other debt securities 1 — — 858 4 858 4 Total investment securities 20 $ 11,915 $ 20 $ 5,236 $ 69 $ 17,151 $ 89 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 — $ — $ — $ — $ — $ — $ — Municipal and other tax-exempt 1 17 $ 375 $ — $ 10,289 $ 713 $ 10,664 $ 713 Residential mortgage-backed securities: U. S. government agencies: FNMA 4 97,910 267 15,401 6 113,311 273 FHLMC 1 — — 22,338 198 22,338 198 GNMA 11 349,631 612 — — 349,631 612 Total U.S. government agencies 16 447,541 879 37,739 204 485,280 1,083 Private issue 1 : Alt-A loans 5 8,513 241 8,291 206 16,804 447 Jumbo-A loans 9 7,076 36 7,877 329 14,953 365 Total private issue 14 15,589 277 16,168 535 31,757 812 Total residential mortgage-backed securities 30 463,130 1,156 53,907 739 517,037 1,895 Commercial mortgage-backed securities guaranteed by U.S. government agencies 11 103,955 37 65,857 85 169,812 122 Other debt securities 2 — — 4,151 249 4,151 249 Perpetual preferred stocks — — — — — — — Equity securities and mutual funds 30 — — 889 14 889 14 Total available for sale securities 90 $ 567,460 $ 1,193 $ 135,093 $ 1,800 $ 702,553 $ 2,993 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. This determination considers current and forecasted liquidity requirements, regulatory and capital requirements and securities portfolio management. Based on this evaluation as of June 30, 2017 , the Company does not intend to sell any impaired available for sale securities before fair value recovers to the current amortized cost and it is more-likely-than-not that the Company will not be required to sell impaired securities before fair value recovers, which may be maturity. Fair Value Option Securities Fair value option securities represent securities which the Company has elected to carry at fair value and are separately identified on the Consolidated Balance Sheets. Changes in the fair value are recognized in earnings as they occur. Certain U.S. Treasury securities, 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): June 30, 2017 Dec. 31, 2016 June 30, 2016 Fair Value Net Unrealized Gain (Loss) Fair Value Net Unrealized Gain (Loss) Fair Value Net Unrealized Gain (Loss) U.S. Treasury $ — $ — $ — $ — $ 25,306 $ (43 ) U.S. government agency residential mortgage-backed securities 445,169 1,247 77,046 (1,777 ) 237,959 4,476 Total $ 445,169 $ 1,247 $ 77,046 $ (1,777 ) $ 263,265 $ 4,433 Restricted Equity Securities Restricted equity securities primarily include stock we are required to hold as members of the Federal Reserve system and the 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 are restricted and they lack a market. A summary of restricted equity securities follows (in thousands): June 30, 2017 Dec. 31, 2016 June 30, 2016 Federal Reserve stock $ 36,676 $ 36,498 $ 36,283 Federal Home Loan Bank stock 274,113 270,541 283,155 Other 244 201 201 Total $ 311,033 $ 307,240 $ 319,639

Derivatives

Derivatives	6 Months Ended
	Jun. 30, 2017
Derivative Instrument Detail [Abstract]
Derivatives [Text Block]	Derivatives 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 reported in earnings as they occur. Credit risk is also considered in determining fair value. When bilateral netting agreements or similar arrangements 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 type by counterparty basis. Derivative contracts may 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. None of these derivative contracts have been designated as hedging instruments for accounting purposes. Customer Risk Management Programs BOK Financial offers programs to permit its customers to manage various risks, including fluctuations in energy, cattle and other agricultural products, interest rates and foreign exchange rates with derivative contracts. Customers may also manage interest rate risk through interest rate swaps used by borrowers to modify interest rate terms of their loans or to-be-announced securities used by 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 the risk of 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. Internal Risk Management Programs BOK Financial may use derivative contracts in managing its interest rate sensitivity, as part of its economic hedge of the change in the fair value of mortgage servicing rights and as an economic hedge of trading securities. As of June 30, 2017 , derivative contracts under the internal risk management programs were primarily used as part of the economic hedges of the change in the fair value of the mortgage servicing rights and trading securities. As discussed in Note 6 , 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 6 for additional discussion of notional, fair value and impact on earnings of these contracts. The following table summarizes the fair values of derivative contracts recorded as “derivative contracts” assets and liabilities in the balance sheet at June 30, 2017 (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 $ 16,174,687 $ 57,948 $ (29,034 ) $ 28,914 $ — $ 28,914 Interest rate swaps 1,450,193 29,932 — 29,932 (2,206 ) 27,726 Energy contracts 891,480 56,824 (20,546 ) 36,278 (21,267 ) 15,011 Agricultural contracts 45,250 3,541 (1,027 ) 2,514 — 2,514 Foreign exchange contracts 169,529 162,429 — 162,429 (7 ) 162,422 Equity option contracts 100,159 4,437 — 4,437 (920 ) 3,517 Total customer risk management programs 18,831,298 315,111 (50,607 ) 264,504 (24,400 ) 240,104 Internal risk management programs 10,680,498 40,185 — 40,185 — 40,185 Total derivative contracts $ 29,511,796 $ 355,296 $ (50,607 ) $ 304,689 $ (24,400 ) $ 280,289 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 $ 16,174,687 $ 53,829 $ (29,034 ) $ 24,795 $ — $ 24,795 Interest rate swaps 1,450,193 29,982 — 29,982 (15,396 ) 14,586 Energy contracts 874,625 53,895 (20,546 ) 33,349 — 33,349 Agricultural contracts 45,262 3,538 (1,027 ) 2,511 (2,511 ) — Foreign exchange contracts 169,553 162,276 — 162,276 (3,188 ) 159,088 Equity option contracts 100,159 4,437 — 4,437 — 4,437 Total customer risk management programs 18,814,479 307,957 (50,607 ) 257,350 (21,095 ) 236,255 Internal risk management programs 8,310,950 49,564 — 49,564 — 49,564 Total derivative contracts $ 27,125,429 $ 357,521 $ (50,607 ) $ 306,914 $ (21,095 ) $ 285,819 1 Notional amounts for commodity contracts are converted into dollar-equivalent amounts based on dollar prices at the inception of the contract. 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 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 $ 16,637,532 $ 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. The following table summarizes the fair values of derivative contracts recorded as “derivative contracts” assets and liabilities in the balance sheet at June 30, 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 $ 18,774,134 $ 183,118 $ (67,383 ) $ 115,735 $ — $ 115,735 Interest rate swaps 1,299,985 54,978 — 54,978 (1,100 ) 53,878 Energy contracts 757,669 59,103 (33,996 ) 25,107 (155 ) 24,952 Agricultural contracts 50,848 2,488 (1,609 ) 879 (37 ) 842 Foreign exchange contracts 701,436 675,804 — 675,804 (5,054 ) 670,750 Equity option contracts 116,901 4,236 — 4,236 (478 ) 3,758 Total customer risk management programs 21,700,973 979,727 (102,988 ) 876,739 (6,824 ) 869,915 Internal risk management programs 1,337,000 13,758 — 13,758 — 13,758 Total derivative contracts $ 23,037,973 $ 993,485 $ (102,988 ) $ 890,497 $ (6,824 ) $ 883,673 Liabilities 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 $ 18,662,334 $ 179,443 $ (67,383 ) $ 112,060 $ (103,724 ) $ 8,336 Interest rate swaps 1,299,985 55,404 — 55,404 (32,597 ) 22,807 Energy contracts 734,538 58,033 (33,996 ) 24,037 (11,784 ) 12,253 Agricultural contracts 50,843 2,476 (1,609 ) 867 — 867 Foreign exchange contracts 701,219 675,383 — 675,383 (4,723 ) 670,660 Equity option contracts 116,901 4,236 — 4,236 — 4,236 Total customer risk management programs 21,565,820 974,975 (102,988 ) 871,987 (152,828 ) 719,159 Internal risk management programs — — — — — — Total derivative contracts $ 21,565,820 $ 974,975 $ (102,988 ) $ 871,987 $ (152,828 ) $ 719,159 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 income statement (in thousands): Three Months Ended June 30, 2017 June 30, 2016 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 $ 9,205 $ — $ 9,862 $ — Interest rate swaps 665 — 723 — Energy contracts 1,666 — 2,749 — Agricultural contracts 11 — 32 — Foreign exchange contracts 90 — 134 — Equity option contracts — — — — Total customer risk management programs 11,637 — 13,500 — Internal risk management programs 6,485 3,241 (9 ) 10,766 Total derivative contracts $ 18,122 $ 3,241 $ 13,491 $ 10,766 Six Months Ended June 30, 2017 June 30, 2016 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 $ 17,232 $ — $ 17,302 $ — Interest rate swaps 1,124 — 1,048 — Energy contracts 4,539 — 3,445 — Agricultural contracts 20 — 61 — Foreign exchange contracts 360 — 512 — Equity option contracts — — — — Total customer risk management programs 23,275 — 22,368 — Internal risk management programs 6,018 2,791 (9 ) 17,904 Total derivative contracts $ 29,293 $ 2,791 $ 22,359 $ 17,904

Loans and Allowances for Credit

Loans and Allowances for Credit Losses	6 Months Ended
	Jun. 30, 2017
Loans Receivable, Net [Abstract]
Loans [Text Block]	Loans and Allowances for Credit Losses 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 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 mortgage loans guaranteed by U.S. government agencies, are as follows. Interest is accrued at the applicable interest rate on the principal amount outstanding. 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 more than 90 days 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 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, excluding loans guaranteed by U.S. government agencies. 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 value, debt service ratio and other underwriting standards. Nonaccruing loans may be renewed and will remain classified as nonaccruing. 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 a quarterly evaluation of available cash resources and collateral value 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. 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 may have 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 Sheets. Guaranteed loans are considered 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 the 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 based on the modified rate. 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 credit losses. Classes are a further disaggregation of portfolio segments based on the risk characteristics of the loans and the Company’s method for monitoring and assessing credit risk. Portfolio segments of the loan portfolio are as follows (in thousands): June 30, 2017 December 31, 2016 Fixed Rate Variable Rate Non-accrual Total Fixed Rate Variable Rate Non-accrual Total Commercial $ 2,198,066 $ 8,242,732 $ 197,157 $ 10,637,955 $ 2,327,085 $ 7,884,786 $ 178,953 $ 10,390,824 Commercial real estate 594,542 3,090,275 3,775 3,688,592 624,187 3,179,338 5,521 3,809,046 Residential mortgage 1,597,587 297,376 44,235 1,939,198 1,647,357 256,255 46,220 1,949,832 Personal 150,728 766,900 272 917,900 154,971 684,697 290 839,958 Total $ 4,540,923 $ 12,397,283 $ 245,439 $ 17,183,645 $ 4,753,600 $ 12,005,076 $ 230,984 $ 16,989,660 Accruing loans past due (90 days) 1 $ 1,414 $ 5 June 30, 2016 Fixed Rate Variable Rate Non-accrual Total Commercial $ 1,994,415 $ 8,180,033 $ 181,989 $ 10,356,437 Commercial real estate 612,822 2,961,364 7,780 3,581,966 Residential mortgage 1,586,116 237,746 57,061 1,880,923 Personal 109,447 477,622 354 587,423 Total $ 4,302,800 $ 11,856,765 $ 247,184 $ 16,406,749 Accruing loans past due (90 days) 1 $ 2,899 1 Excludes residential mortgage loans guaranteed by agencies of the U.S. government At June 30, 2017 , $5.7 billion or 33 percent of our total loan portfolio is to businesses and individuals attributed to the Texas market and $3.4 billion or 20 percent of the total loan portfolio is to businesses and individuals attributed to the Oklahoma market. These geographic concentrations subject the loan portfolio to the general economic conditions within these areas. 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 ongoing 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 ongoing 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 June 30, 2017 , commercial loans attributed to the Texas market totaled $3.6 billion or 33 percent of the commercial loan portfolio segment and commercial loans attributed to the Oklahoma market totaled $2.1 billion or 19 percent of the commercial loan portfolio segment. The commercial loan portfolio segment is further divided into loan classes. The energy loan class totaled $2.8 billion or 17 percent of total loans at June 30, 2017 , including $2.4 billion of outstanding loans to energy producers. Approximately 58 percent of committed production loans are secured by properties primarily producing oil and 42 percent are secured by properties producing natural gas. The services loan class totaled $3.0 billion or 17 percent of total loans at June 30, 2017 . Approximately $1.5 billion of loans in the services category consist of loans with individual balances of less than $10 million . Businesses included in the services class include governmental, finance and insurance, not-for-profit, educational services and loans to entities providing services for real estate and construction. The healthcare loan class totaled $2.2 billion or 13 percent of total loans at June 30, 2017 . 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. 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 June 30, 2017 , 32 percent of commercial real estate loans are secured by properties primarily located in the Dallas and Houston areas of Texas. An additional 12 percent of commercial real estate loans are secured by properties located primarily in the Tulsa and Oklahoma City metropolitan areas of 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 unsecured loans. Residential mortgage and personal loans are made in accordance with underwriting policies we believe to be conservative and are fully documented. Loans may be individually underwritten or credit scored based on size and other criteria. 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 percent . Loan-to-value (“LTV”) ratios are tiered from 60 percent to 100 percent , 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 June 30, 2017 , residential mortgage loans included $192 million 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 $758 million at June 30, 2017 . Approximately 65 percent of the home equity loan portfolio is comprised of first lien loans and 35 percent of the home equity portfolio is comprised of junior lien loans. Junior lien loans are distributed 49 percent to amortizing term loans and 51 percent to revolving lines of credit. Home equity loans generally require a minimum FICO score of 700 and a maximum DTI of 40 percent. 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 a 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. 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 June 30, 2017 , outstanding commitments totaled $9.6 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 June 30, 2017 , outstanding standby letters of credit totaled $615 million . Commercial letters of credit are used to facilitate customer trade transactions with the drafts being drawn when the underlying transaction is consummated. At June 30, 2017 , outstanding commercial letters of credit totaled $3.2 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 6 , the Company also has separate accruals for 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 appropriateness of the allowance for loan losses and accrual for off-balance sheet credit losses (collectively "allowance for credit losses") is assessed by management based on an ongoing quarterly evaluation of the probable estimated losses inherent in the portfolio, including probable losses on both outstanding loans and unused commitments. 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, risk concentration and related factors. There have been no material changes in the approach or techniques utilized in developing the allowance for loan losses and the accrual for off-balance sheet credit losses for the three and six months ended June 30, 2017 . 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 consumer loans are risk graded based on evaluation of the borrowers' ability to repay. Certain commercial loans and most residential mortgage and consumer 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 or modified in a TDR 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 loans’ initial effective interest rate or the fair value of collateral for certain collateral dependent loans. Collateral value of real property 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 are generally not adjusted by the Company. Updated appraisals are obtained at least annually or more frequently if market conditions indicate collateral values have declined. Collateral value of mineral rights is generally determined by our internal staff of engineers based on projected 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 updated 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 estimated loss rates by loan class. The gross loss rate for each loan class is determined by the greater of the current gross loss rate based on the most recent twelve months or a ten-year gross loss rate. Recoveries are not directly considered in the estimation of 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, 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 average risk grade. This comparison determines whether credit risk in each loan class is increasing or decreasing. 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 specific loan classes which have not yet been represented in the 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 loan or loan class. These factors include trends in the economy of our primary lending areas, concentrations in large balance loans and other relevant factors. An accrual for off-balance sheet credit losses is included in Other liabilities in the Consolidated Balance Sheets. The appropriateness of this 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. The activity in the allowance for loan losses and the allowance for off-balance sheet credit losses related to loan commitments and standby letters of credit for the three months ended June 30, 2017 is summarized as follows (in thousands): Commercial Commercial Real Estate Residential Mortgage Personal Nonspecific Allowance Total Allowance for loan losses: Beginning balance $ 137,616 $ 58,343 $ 18,177 $ 7,247 $ 27,327 $ 248,710 Provision for loan losses 1,546 105 (47 ) 1,358 47 3,009 Loans charged off (1,703 ) (76 ) (40 ) (1,053 ) — (2,872 ) Recoveries 283 208 169 554 — 1,214 Ending balance $ 137,742 $ 58,580 $ 18,259 $ 8,106 $ 27,374 $ 250,061 Allowance for off-balance sheet credit losses: Beginning balance $ 9,288 $ 106 $ 40 $ 6 $ — $ 9,440 Provision for off-balance sheet credit losses (2,987 ) (22 ) (2 ) 2 — (3,009 ) Ending balance $ 6,301 $ 84 $ 38 $ 8 $ — $ 6,431 Total provision for credit losses $ (1,441 ) $ 83 $ (49 ) $ 1,360 $ 47 $ — The activity in the allowance for loan losses and the allowance for off-balance sheet credit losses related to loan commitments and standby letters of credit for the six months ended June 30, 2017 is summarized as follows (in thousands): Commercial Commercial Real Estate Residential Mortgage Personal Nonspecific Allowance Total Allowance for loan losses: Beginning balance $ 140,213 $ 50,749 $ 18,224 $ 8,773 $ 28,200 $ 246,159 Provision for loan losses (1,809 ) 6,964 (86 ) 570 (826 ) 4,813 Loans charged off (2,127 ) (76 ) (276 ) (2,546 ) — (5,025 ) Recoveries 1,465 943 397 1,309 — 4,114 Ending balance $ 137,742 $ 58,580 $ 18,259 $ 8,106 $ 27,374 $ 250,061 Allowance for off-balance sheet credit losses: Beginning balance $ 11,063 $ 123 $ 50 $ 8 $ — $ 11,244 Provision for off-balance sheet credit losses (4,762 ) (39 ) (12 ) — — (4,813 ) Ending balance $ 6,301 $ 84 $ 38 $ 8 $ — $ 6,431 Total provision for credit losses $ (6,571 ) $ 6,925 $ (98 ) $ 570 $ (826 ) $ — The activity in the allowance for loan losses and the allowance for off-balance sheet credit losses related to loan commitments and standby letters of credit for the three months ended June 30, 2016 is summarized as follows (in thousands): Commercial Commercial Real Estate Residential Mortgage Personal Nonspecific Allowance Total Allowance for loan losses: Beginning balance $ 139,793 $ 44,453 $ 18,467 $ 5,022 $ 25,421 $ 233,156 Provision for loan losses 12,478 2,010 368 1,443 1,263 17,562 Loans charged off (7,355 ) — (345 ) (1,145 ) — (8,845 ) Recoveries 223 282 200 681 — 1,386 Ending balance $ 145,139 $ 46,745 $ 18,690 $ 6,001 $ 26,684 $ 243,259 Allowance for off-balance sheet credit losses: Beginning balance $ 6,319 $ 228 $ 58 $ 2 $ — $ 6,607 Provision for off-balance sheet credit losses 2,433 (25 ) 4 26 — 2,438 Ending balance $ 8,752 $ 203 $ 62 $ 28 $ — $ 9,045 Total provision for credit losses $ 14,911 $ 1,985 $ 372 $ 1,469 $ 1,263 $ 20,000 The activity in the allowance for loan losses and the allowance for off-balance sheet credit losses related to loan commitments and standby letters of credit for the six months ended June 30, 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 43,575 4,987 (363 ) 2,909 (3,442 ) 47,666 Loans charged off (29,481 ) — (819 ) (2,536 ) — (32,836 ) Recoveries 711 367 363 1,464 — 2,905 Ending balance $ 145,139 $ 46,745 $ 18,690 $ 6,001 $ 26,684 $ 243,259 Allowance for off-balance sheet credit losses: Beginning balance $ 1,506 $ 153 $ 30 $ 22 $ — $ 1,711 Provision for off-balance sheet credit losses 7,246 50 32 6 — 7,334 Ending balance $ 8,752 $ 203 $ 62 $ 28 $ — $ 9,045 Total provision for credit losses $ 50,821 $ 5,037 $ (331 ) $ 2,915 $ (3,442 ) $ 55,000 The allowance for loan losses and recorded investment of the related loans by portfolio segment for each impairment measurement method at June 30, 2017 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 $ 10,440,798 $ 128,049 $ 197,157 $ 9,693 $ 10,637,955 $ 137,742 Commercial real estate 3,684,817 58,580 3,775 — 3,688,592 58,580 Residential mortgage 1,894,963 18,259 44,235 — 1,939,198 18,259 Personal 917,628 8,106 272 — 917,900 8,106 Total 16,938,206 212,994 245,439 9,693 17,183,645 222,687 Nonspecific allowance — — — — — 27,374 Total $ 16,938,206 $ 212,994 $ 245,439 $ 9,693 $ 17,183,645 $ 250,061 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 June 30, 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 $ 10,174,448 $ 140,911 $ 181,989 $ 4,228 $ 10,356,437 $ 145,139 Commercial real estate 3,574,186 46,727 7,780 18 3,581,966 46,745 Residential mortgage 1,823,862 18,626 57,061 64 1,880,923 18,690 Personal 587,069 6,001 354 — 587,423 6,001 Total 16,159,565 212,265 247,184 4,310 16,406,749 216,575 Nonspecific allowance — — — — — 26,684 Total $ 16,159,565 $ 212,265 $ 247,184 $ 4,310 $ 16,406,749 $ 243,259 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 consumer 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 consumer 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 June 30, 2017 is as follows (in thousands): Internally Risk Graded Non-Graded Total Recorded Investment Related Allowance Recorded Investment Related Allowance Recorded Investment Related Allowance Commercial $ 10,612,477 $ 136,819 $ 25,478 $ 923 $ 10,637,955 $ 137,742 Commercial real estate 3,688,592 58,580 — — 3,688,592 58,580 Residential mortgage 216,007 2,976 1,723,191 15,283 1,939,198 18,259 Personal 824,318 5,742 93,582 2,364 917,900 8,106 Total 15,341,394 204,117 1,842,251 18,570 17,183,645 222,687 Nonspecific allowance — — — — — 27,374 Total $ 15,341,394 $ 204,117 $ 1,842,251 $ 18,570 $ 17,183,645 $ 250,061 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 June 30, 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 $ 10,331,701 $ 144,217 $ 24,736 $ 922 $ 10,356,437 $ 145,139 Commercial real estate 3,581,966 46,745 — — 3,581,966 46,745 Residential mortgage 202,520 2,995 1,678,403 15,695 1,880,923 18,690 Personal 500,240 3,624 87,183 2,377 587,423 6,001 Total 14,616,427 197,581 1,790,322 18,994 16,406,749 216,575 Nonspecific allowance — — — — — 26,684 Total $ 14,616,427 $ 197,581 $ 1,790,322 $ 18,994 $ 16,406,749 $ 243,259 Loans are considered to be performing if they are in compliance with the original terms of the agreement and currently exhibit no factors that cause management to have doubts about the borrowers' ability to remain in compliance with the original terms of the agreement, which is consistent with the regulatory guideline of “pass.” Performing loans also include past due residential mortgages that are guaranteed by agencies of the U.S. government that continue to accrue interest based on criteria of the guarantors' 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 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 June 30, 2017 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 $ 2,376,368 $ 120,473 $ 226,407 $ 123,992 $ — $ — $ 2,847,240 Services 2,921,510 12,452 17,111 7,754 — — 2,958,827 Wholesale/retail 1,507,063 16,224 9,788 10,620 — — 1,543,695 Manufacturing 513,442 6,540 16,499 9,656 — — 546,137 Healthcare 2,130,339 33,554 33,120 24,505 — — 2,221,518 Other commercial and industrial 453,712 2,961 17,861 20,526 25,374 104 520,538 Total commercial 9,902,434 192,204 320,786 197,053 25,374 104 10,637,955 Commercial real estate: Residential construction and land development 138,790 — 751 2,051 — — 141,592 Retail 720,730 1,774 — 301 — — 722,805 Office 859,722 2,855 — 396 — — 862,973 Multifamily 947,950 — 4,420 10 — — 952,380 Industrial 693,635 — — — — — 693,635 Other commercial real estate 314,187 — 3 1,017 — — 315,207 Total commercial real estate 3,675,014 4,629 5,174 3,775 — — 3,688,592 Residential mortgage: Permanent mortgage 212,563 1,693 478 1,273 750,891 22,142 989,

Acquisitions

Acquisitions	6 Months Ended
	Jun. 30, 2017
Business Combinations [Abstract]
Business Combination Disclosure [Text Block]	Acquisitions On December 1, 2016 , the Company acquired MBT Bancshares (“MBT”), parent company of Missouri Bank and Trust of Kansas City (“Mobank”) following regulatory approval of the transaction. Mobank operated four banking branches in the Kansas City, Mo. 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 21, 2017, Mobank was merged with the Bank of Kansas City division of BOKF, NA. All branches in the Kansas City market will operate under the Mobank name. The preliminary purchase price allocation was updated in the first quarter of 2017 resulting in a $2.0 million increase in identifiable intangibles, $1.5 million decrease in premises and equipment and other repossessed assets, and a $526 thousand decrease in goodwill.

Mortgage Banking Activities

Mortgage Banking Activities	6 Months Ended
	Jun. 30, 2017
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 retained for investment. Residential mortgage loans originated for sale by the Company are carried at fair value based on sales commitments and market quotes. Changes in the fair value of mortgage loans held for sale are included in Other operating revenue – Mortgage banking revenue. Residential mortgage loans held for sale also includes the fair value of residential mortgage loan commitments and forward sale commitments which are considered derivative contracts that have not been designated as hedging instruments for accounting purposes. 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): June 30, 2017 Dec. 31, 2016 June 30, 2016 Unpaid Principal Balance/ Notional Fair Value Unpaid Principal Balance/ Notional Fair Value Unpaid Principal Balance/ Notional Fair Value Residential mortgage loans held for sale $ 269,772 $ 275,179 $ 286,414 $ 286,971 $ 404,507 $ 417,542 Residential mortgage loan commitments 362,088 10,993 318,359 9,733 965,631 25,499 Forward sales contracts 587,595 1,087 569,543 5,193 1,216,966 (12,313 ) $ 287,259 $ 301,897 $ 430,728 No residential mortgage loans held for sale were 90 days or more past due or considered impaired as of June 30, 2017 , December 31, 2016 or June 30, 2016 . No credit losses were recognized on residential mortgage loans held for sale for the three and six month periods ended June 30, 2017 and 2016 . Mortgage banking revenue was as follows (in thousands): Three Months Ended Six Months Ended 2017 2016 2017 2016 Production revenue: Net realized gains on sale of mortgage loans $ 11,787 $ 15,865 $ 20,402 $ 24,314 Net change in unrealized gain on mortgage loans held for sale 985 3,884 4,827 7,167 Net change in the fair value of mortgage loan commitments (3,274 ) 5,329 1,260 17,365 Net change in the fair value of forward sales contracts 4,342 (5,992 ) (4,106 ) (13,113 ) Total production revenue 13,840 19,086 22,383 35,733 Servicing revenue 16,436 15,798 33,084 31,251 Total mortgage banking revenue $ 30,276 $ 34,884 $ 55,467 $ 66,984 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 for accounting purposes 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 Mortgage servicing rights may be originated or purchased. Both originated and purchased mortgage servicing rights are initially recognized at fair value. The Company has elected to carry all mortgage servicing rights at fair value. Changes in the fair value are recognized in earnings as they occur. 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): June 30, Dec. 31, June 30, Number of residential mortgage loans serviced for others 138,335 139,340 137,210 Outstanding principal balance of residential mortgage loans serviced for others $ 22,095,232 $ 21,997,568 $ 21,178,387 Weighted average interest rate 3.95 % 3.97 % 4.06 % Remaining term (in months) 299 301 301 Activity in capitalized mortgage servicing rights during the three months ended June 30, 2017 was as follows (in thousands): Purchased Originated Total Balance, March 31, 2017 $ 8,316 $ 241,087 $ 249,403 Additions, net — 11,078 11,078 Change in fair value due to scheduled payments and full-balance payoffs (464 ) (7,835 ) (8,299 ) Change in fair value due to market assumption changes 143 (7,086 ) (6,943 ) Balance, June 30, 2017 $ 7,995 $ 237,244 $ 245,239 Purchased Originated Total Balance, Dec. 31, 2016 $ 8,909 $ 238,164 $ 247,073 Additions, net — 19,514 19,514 Change in fair value due to scheduled payments and full-balance payoffs (973 ) (15,288 ) (16,261 ) Change in fair value due to market assumption changes 59 (5,146 ) (5,087 ) Balance, June 30, 2017 $ 7,995 $ 237,244 $ 245,239 Activity in capitalized mortgage servicing rights during the three months ended June 30, 2016 was as follows (in thousands): Purchased Originated Total Balance, March 31, 2016 $ 5,949 $ 190,106 $ 196,055 Additions, net — 20,773 20,773 Change in fair value due to scheduled payments and full-balance payoffs (730 ) (9,068 ) (9,798 ) Change in fair value due to market assumption changes (1,152 ) (15,131 ) (16,283 ) Balance, June 30, 2016 $ 4,067 $ 186,680 $ 190,747 Purchased Originated Total Balance, Dec. 31, 2015 $ 9,911 $ 208,694 $ 218,605 Additions, net — 34,355 34,355 Change in fair value due to scheduled payments and full-balance payoffs (1,356 ) (16,586 ) (17,942 ) Change in fair value due to market assumption changes (4,488 ) (39,783 ) (44,271 ) Balance, June 30, 2016 $ 4,067 $ 186,680 $ 190,747 Changes in the fair value of mortgage servicing rights are included in Other operating revenue in the Consolidated Statements of Earnings. Changes in fair value due to actual loan payments are included in Mortgage banking costs. Changes in fair value due to market assumption changes are reported separately. Changes in fair value due to market assumption changes during the period relate to assets held at the reporting date. 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 based on significant unobservable inputs were as follows: June 30, Dec. 31, June 30, Discount rate – risk-free rate plus a market premium 9.84% 10.08% 10.09% Prepayment rate - based upon loan interest rate, original term and loan type 8.61%-15.91% 8.98%-16.91% 9.26%-42.77% Loan servicing costs – annually per loan based upon loan type: Performing loans $65-$120 $63 - $120 $63 - $120 Delinquent loans $150-$500 $150 - $500 $150 - $500 Loans in foreclosure $1,000-$4,250 $650 - $4,250 $650 - $4,250 Escrow earnings rate – indexed to rates paid on deposit accounts with comparable average life 1.95% 1.98% 0.99% Primary/secondary mortgage rate spread 105 bps 105 bps 115 bps 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 aging status of our mortgage loans serviced for others by investor at June 30, 2017 follows (in thousands): Past Due Current 30 to 59 Days 60 to 89 Days 90 Days or More Total FHLMC $ 8,083,330 $ 48,659 $ 12,294 $ 27,338 $ 8,171,621 FNMA 6,756,211 46,918 10,679 23,981 6,837,789 GNMA 6,331,439 170,889 47,335 16,082 6,565,745 Other 514,272 3,278 932 1,595 520,077 Total $ 21,685,252 $ 269,744 $ 71,240 $ 68,996 $ 22,095,232 The Company has 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 and to service loans in accordance with investor guidelines. The Company has established accruals for losses related to these obligations that are included in Other liabilities in the Consolidated Balance Sheets and in Mortgage banking costs in the Consolidated Statements of Earnings. The Company repurchased five loans from the agencies for $ 1.3 million during the second quarter of 2017 . There were four indemnifications on loans paid during the second quarter of 2017 . Losses recognized on repurchases were insignificant. A summary of unresolved deficiency requests from the agencies follows (in thousands, except for number of unresolved deficiency requests): June 30, 2017 2016 Number of unresolved deficiency requests 206 211 Aggregate outstanding principal balance subject to unresolved deficiency requests $ 13,370 $ 15,920 Unpaid principal balance subject to indemnification by the Company 5,074 5,519 The activity in the accruals for mortgage losses related to repurchases is summarized as follows (in thousands). Three Months Ended Six Months Ended 2017 2016 2017 2016 Beginning balance $ 2,587 $ 2,974 $ 2,788 $ 3,359 Provision for losses (895 ) 368 (1,094 ) 250 Charge-offs, net (45 ) (89 ) (47 ) (356 ) Ending balance $ 1,647 $ 3,253 $ 1,647 $ 3,253

Commitments and Contingent Liab

Commitments and Contingent Liabilities	6 Months Ended
	Jun. 30, 2017
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 was approved by the Court in a final order, the Company funded the settlement, and the settlement has been implemented. 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 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 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. On March 14, 2017, the Bank was sued in the United States District Court for the Northern District of Oklahoma by bondholders in a second putative class action. The bondholders in this second action allege two individuals purchased facilities from the principals who are the subject of the SEC New Jersey proceedings by means of the fraudulent sale of $60 million of municipal securities for which the Bank also served as indenture trustee. The bondholders allege the Bank failed to disclose that the seller of the purchased facilities had engaged in the conduct complained of in the New Jersey action. The Bank properly performed all duties as indenture trustee of this second set of municipal securities, timely commenced proceedings against the issuer of the securities when default occurred, is cooperating with the SEC in actions against the two principals, is not a target of the SEC proceedings, and has been advised by counsel that the Bank has valid defenses to the claims of these bondholders. It is the opinion of management that no loss is probable at this time. The County of Bernalillo, New Mexico, commenced arbitration pursuant to the Arbitration Rules of FINRA seeking recovery of $5.6 million alleging that various municipal bonds purchased by the elected County Treasurer of Bernalillo County, New Mexico, from BOK Financial Securities, Inc. were unsuitable. The arbitration was conducted in July 2017. Management has been advised by counsel that a loss is not probable. On March 30, 2017, two deposit customers of the Bank sued the Bank in the District Court of Harris County, Texas. A judgment creditor had served a garnishment summons on the Bank. The deposit customers allege that, because the Bank was unable to produce adequate documentation of ownership of a series of deposit accounts at the Bank owned by them, they were compelled to enter into a settlement agreement with the judgment creditor pursuant to which the Bank paid $4.2 million from the accounts to the judgment creditor. The two deposit customers seek $7 million . Management has been advised by counsel that a loss is not probable and that the amount of the liability, if any, cannot be quantified at this time. On March 7, 2017, a plaintiff filed a putative class action in the United States District Court for the Northern District of Texas alleging an extended overdraft fee charged by BOKF, NA is interest and exceeds permitted rates. BOKF, NA was previously sued in a class action in the United States District Court for the Northern District of Oklahoma making the same allegations. Pursuant to a motion to dismiss, the Northern District of Oklahoma Court action was dismissed. Other courts considering the question whether extended overdraft fees are interest have likewise determined such fees are not interest. BOKF, NA has moved to dismiss the action. Management is advised by counsel that a loss is not probable and that the loss, if any, cannot be reasonably estimated. 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 $4.0 million at June 30, 2017 . 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 types of investments. Consolidated tax credit investment entities represent the Company's interest in entities earning federal new market tax credits related to qualifying loans. 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. Other consolidated alternative investments include entities held under merchant banking authority. While the Company owns a majority of the voting interest in these entities, its ability to manage daily operations is limited by applicable banking regulations. Consolidated other assets includes total tangible assets, identifiable intangible assets and goodwill held by these entities. 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 primarily 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 June 30, 2017 , December 31, 2016 and June 30, 2016 is as follows (in thousands): June 30, 2017 Loans Other assets Other liabilities Other borrowings Non-controlling interests Consolidated: Private equity funds $ — $ 16,905 $ — $ — $ 14,199 Tax credit entities 10,000 11,274 — 10,964 10,000 Other — 15,894 1,621 878 2,877 Total consolidated $ 10,000 $ 44,073 $ 1,621 $ 11,842 $ 27,076 Unconsolidated: Tax credit entities $ 59,744 $ 148,525 $ 63,822 $ — $ — Other — 33,155 13,680 — — Total unconsolidated $ 59,744 $ 181,680 $ 77,502 $ — $ — Dec. 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 $ — $ — June 30, 2016 Loans Other assets Other liabilities Other borrowings Non-controlling interests Consolidated: Private equity funds $ — $ 20,469 $ — $ — $ 16,316 Tax credit entities 10,000 11,895 — 10,964 10,000 Other — 35,387 2,004 2,272 7,589 Total consolidated $ 10,000 $ 67,751 $ 2,004 $ 13,236 $ 33,905 Unconsolidated: Tax credit entities $ 32,679 $ 102,138 $ 30,953 $ — $ — Other — 23,439 13,767 — — Total unconsolidated $ 32,679 $ 125,577 $ 44,720 $ — $ — Other Commitments and Contingencies At June 30, 2017 , Cavanal Hill Funds’ assets included U.S. Treasury, cash management and tax-free money market funds. Assets of these funds consist of highly-rated, short-term obligations of the U.S. Treasury, corporate issuers and U.S. states and municipalities. The net asset value of units in these funds was $1.00 at June 30, 2017 . 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 2017 or 2016 .

Shareholders' Equity

Shareholders' Equity	6 Months Ended
	Jun. 30, 2017
Stockholders' Equity Note [Abstract]
Shareholders' Equity [Text Block]	Shareholders' Equity On July 25, 2017 , the Company declared a quarterly cash dividend of $0.44 per common share on or about August 25, 2017 to shareholders of record as of August 11, 2017 . Dividends declared were $0.44 per share and $0.88 per share during the three and six months ended June 30, 2017 and $0.43 per share and $0.86 per share during the three and six months ended June 30, 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 the third quarter of 2011. Such amounts are being 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. 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 Total Balance, Dec. 31, 2015 $ 23,284 $ 68 $ (1,765 ) $ 21,587 Net change in unrealized gain (loss) 166,566 — — 166,566 Reclassification adjustments included in earnings: Interest revenue, Investment securities, Taxable securities — (112 ) — (112 ) Gain on available for sale securities, net (9,290 ) — — (9,290 ) Other comprehensive income (loss), before income taxes 157,276 (112 ) — 157,164 Federal and state income taxes 1 61,163 (44 ) — 61,119 Other comprehensive income (loss), net of income taxes 96,113 (68 ) — 96,045 Balance, June 30, 2016 $ 119,397 $ — $ (1,765 ) $ 117,632 Balance, Dec. 31, 2016 $ (9,087 ) $ — $ (1,880 ) $ (10,967 ) Net change in unrealized gain (loss) 33,369 — — 33,369 Reclassification adjustments included in earnings: Gain on available for sale securities, net (2,429 ) — — (2,429 ) Other comprehensive income, before income taxes 30,940 — — 30,940 Federal and state income taxes 1 12,009 — 12,009 Other comprehensive income, net of income taxes 18,931 — — 18,931 Balance, June 30, 2017 $ 9,844 $ — $ (1,880 ) $ 7,964 1 Calculated using a 39 percent effective tax rate.

Earnings Per Share

Earnings Per Share	6 Months Ended
	Jun. 30, 2017
Earnings Per Share [Abstract]
Earnings Per Share [Text Block]	Earnings Per Share (In thousands, except share and per share amounts) Three Months Ended Six Months Ended 2017 2016 2017 2016 Numerator: Net income attributable to BOK Financial Corp. shareholders $ 88,147 $ 65,801 $ 176,503 $ 108,365 Less: Earnings allocated to participating securities 926 821 1,929 1,359 Numerator for basic earnings per share – income available to common shareholders 87,221 64,980 174,574 107,006 Effect of reallocating undistributed earnings of participating securities 1 — 1 — Numerator for diluted earnings per share – income available to common shareholders $ 87,222 $ 64,980 $ 174,575 $ 107,006 Denominator: Weighted average shares outstanding 65,416,274 66,069,392 65,436,909 66,100,279 Less: Participating securities included in weighted average shares outstanding 686,522 823,505 714,165 829,065 Denominator for basic earnings per common share 64,729,752 65,245,887 64,722,744 65,271,214 Dilutive effect of employee stock compensation plans 1 63,382 57,039 65,578 45,963 Denominator for diluted earnings per common share 64,793,134 65,302,926 64,788,322 65,317,177 Basic earnings per share $ 1.35 $ 1.00 $ 2.70 $ 1.64 Diluted earnings per share $ 1.35 $ 1.00 $ 2.69 $ 1.64 1 Excludes employee stock options with exercise prices greater than current market price. — — — 145,247

Reportable Segments

Reportable Segments	6 Months Ended
	Jun. 30, 2017
Segment Reporting [Abstract]
Reportable Segments [Text Block]	Reportable Segments Reportable segments reconciliation to the Consolidated Financial Statements for the three months ended June 30, 2017 is as follows (in thousands): Commercial Consumer Wealth Management Funds Management and Other BOK Financial Consolidated Net interest revenue from external sources $ 144,164 $ 23,503 $ 10,474 $ 27,063 $ 205,204 Net interest revenue (expense) from internal sources (20,347 ) 11,837 10,325 (1,815 ) — Net interest revenue 123,817 35,340 20,799 25,248 205,204 Provision for credit losses 1,228 926 (93 ) (2,061 ) — Net interest revenue after provision for credit losses 122,589 34,414 20,892 27,309 205,204 Other operating revenue 55,778 52,102 75,569 (1,197 ) 182,252 Other operating expense 59,128 55,709 60,615 75,433 250,885 Net direct contribution 119,239 30,807 35,846 (49,321 ) 136,571 Gain on financial instruments, net 3 5,224 — (5,227 ) — Change in fair value of mortgage servicing rights — (6,943 ) — 6,943 — Gain on repossessed assets, net 1,403 98 — (1,501 ) — Corporate expense allocations 8,862 17,039 9,947 (35,848 ) — Net income before taxes 111,783 12,147 25,899 (13,258 ) 136,571 Federal and state income taxes 43,484 4,725 10,075 (10,579 ) 47,705 Net income 68,299 7,422 15,824 (2,679 ) 88,866 Net income attributable to non-controlling interests — — — 719 719 Net income attributable to BOK Financial Corp. shareholders $ 68,299 $ 7,422 $ 15,824 $ (3,398 ) $ 88,147 Average assets $ 17,596,273 $ 8,845,398 $ 6,763,093 $ (836,193 ) $ 32,368,571 Reportable segments reconciliation to the Consolidated Financial Statements for the six months ended June 30, 2017 is as follows (in thousands): Commercial Consumer Wealth Management Funds Management and Other BOK Financial Consolidated Net interest revenue from external sources $ 278,868 $ 44,632 $ 21,960 $ 60,926 $ 406,386 Net interest revenue (expense) from internal sources (37,140 ) 22,789 19,181 (4,830 ) — Net interest revenue 241,728 67,421 41,141 56,096 406,386 Provision for credit losses (234 ) 2,198 (53 ) (1,911 ) — Net interest revenue after provision for credit losses 241,962 65,223 41,194 58,007 406,386 Other operating revenue 102,048 99,408 149,727 1,365 352,548 Other operating expense 111,565 109,242 121,025 153,764 495,596 Net direct contribution 232,445 55,389 69,896 (94,392 ) 263,338 Gain on financial instruments, net 41 3,557 — (3,598 ) — Change in fair value of mortgage servicing rights — (5,087 ) — 5,087 — Gain (loss) on repossessed assets, net 1,398 (39 ) — (1,359 ) — Corporate expense allocations 17,493 33,908 20,619 (72,020 ) — Net income before taxes 216,391 19,912 49,277 (22,242 ) 263,338 Federal and state income taxes 84,176 7,746 19,169 (25,283 ) 85,808 Net income 132,215 12,166 30,108 3,041 177,530 Net income attributable to non-controlling interests — — — 1,027 1,027 Net income attributable to BOK Financial Corp. shareholders $ 132,215 $ 12,166 $ 30,108 $ 2,014 $ 176,503 Average assets $ 17,517,960 $ 8,747,524 $ 6,960,872 $ (566,196 ) $ 32,660,160 Reportable segments reconciliation to the Consolidated Financial Statements for the three months ended June 30, 2016 is as follows (in thousands): Commercial Consumer Wealth Management Funds Management and Other BOK Financial Consolidated Net interest revenue from external sources $ 118,480 $ 22,349 $ 6,271 $ 35,512 $ 182,612 Net interest revenue (expense) from internal sources (14,575 ) 8,876 $ 7,193 (1,494 ) — Net interest revenue 103,905 31,225 13,464 34,018 182,612 Provision for credit losses 6,852 1,318 (239 ) 12,069 20,000 Net interest revenue after provision for credit losses 97,053 29,907 13,703 21,949 162,612 Other operating revenue 51,497 57,440 75,772 833 185,542 Other operating expense 52,594 62,806 61,414 74,571 251,385 Net direct contribution 95,956 24,541 28,061 (51,789 ) 96,769 Gain on financial instruments, net — 15,045 — (15,045 ) — Change in fair value of mortgage servicing rights — (16,283 ) — 16,283 — Gain (loss) on repossessed assets, net (598 ) 252 — 346 — Corporate expense allocations 8,883 16,630 10,417 (35,930 ) — Net income before taxes 86,475 6,925 17,644 (14,275 ) 96,769 Federal and state income taxes 33,639 2,694 6,864 (12,700 ) 30,497 Net income 52,836 4,231 10,780 (1,575 ) 66,272 Net gain attributable to non-controlling interests — — — 471 471 Net income attributable to BOK Financial Corp. shareholders $ 52,836 $ 4,231 $ 10,780 $ (2,046 ) $ 65,801 Average assets $ 16,973,663 $ 8,774,881 $ 5,765,390 $ 472,108 $ 31,986,042 Reportable segments reconciliation to the Consolidated Financial Statements for the six months ended June 30, 2016 is as follows (in thousands): Commercial Consumer Wealth Management Funds Management and Other BOK Financial Consolidated Net interest revenue from external sources $ 235,116 $ 43,799 $ 12,349 $ 73,920 $ 365,184 Net interest revenue (expense) from internal sources (29,208 ) 18,229 $ 14,857 (3,878 ) — Net interest revenue 205,908 62,028 27,206 70,042 365,184 Provision for credit losses 28,423 3,020 (390 ) 23,947 55,000 Net interest revenue after provision for credit losses 177,485 59,008 27,596 46,095 310,184 Other operating revenue 96,605 111,469 144,518 (9,636 ) 342,956 Other operating expense 108,663 118,524 122,098 144,670 493,955 Net direct contribution 165,427 51,953 50,016 (108,211 ) 159,185 Gain on financial instruments, net — 31,626 — (31,626 ) — Change in fair value of mortgage servicing rights — (44,271 ) — 44,271 — Gain (loss) on repossessed assets, net (680 ) 406 — 274 — Corporate expense allocations 17,627 32,608 20,952 (71,187 ) — Net income before taxes 147,120 7,106 29,064 (24,105 ) 159,185 Federal and state income taxes 57,230 2,764 11,306 (19,375 ) 51,925 Net income 89,890 4,342 17,758 (4,730 ) 107,260 Net loss attributable to non-controlling interests — — — (1,105 ) (1,105 ) Net income attributable to BOK Financial Corp. shareholders $ 89,890 $ 4,342 $ 17,758 $ (3,625 ) $ 108,365 Average assets $ 16,971,339 $ 8,731,085 $ 5,665,218 $ 379,615 $ 31,747,257

Fair Value Measurements

Fair Value Measurements	6 Months Ended
	Jun. 30, 2017
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. 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 three and six months ended June 30, 2017 and 2016 , respectively. Transfers between significant other observable inputs and significant unobservable inputs during the three and six months ended June 30, 2017 and 2016 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 June 30, 2017 , December 31, 2016 or June 30, 2016 . Assets and Liabilities Measured at Fair Value on a Recurring Basis The fair value of financial assets and liabilities measured on a recurring basis was as follows as of June 30, 2017 (in thousands): Total Quoted Prices in Active Markets for Identical Instruments (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Assets: Trading securities: U.S. government agency debentures $ 20,954 $ — $ 20,954 $ — U.S. government agency residential mortgage-backed securities 365,171 — 365,171 — Municipal and other tax-exempt securities 45,444 — 45,444 — Other trading securities 9,845 — 9,845 — Total trading securities 441,414 — 441,414 — Available for sale securities: U.S. Treasury 998 998 — — Municipal and other tax-exempt securities 32,765 — 28,110 4,655 U.S. government agency residential mortgage-backed securities 5,382,377 — 5,382,377 — Privately issued residential mortgage-backed securities 103,383 — 103,383 — Commercial mortgage-backed securities guaranteed by U.S. government agencies 2,782,070 — 2,782,070 — Other debt securities 4,152 — — 4,152 Perpetual preferred stock 16,568 — 16,568 — Equity securities and mutual funds 18,728 3,516 15,212 — Total available for sale securities 8,341,041 4,514 8,327,720 8,807 Fair value option securities – U.S. government agency residential mortgage-backed securities 445,169 — 445,169 — Residential mortgage loans held for sale 287,259 — 274,524 12,735 Mortgage servicing rights 1 245,239 — — 245,239 Derivative contracts, net of cash collateral 2 280,289 20,213 260,076 — Liabilities: Derivative contracts, net of cash collateral 2 285,819 5,919 279,900 — 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 6 , Mortgage Banking Activities. 2 See Note 3 for detail of fair value of derivative contracts by contract type. Derivative contracts in asset positions that were valued based on quoted prices in active markets for identical instruments (Level 1) are primarily exchange-traded energy and interest rate derivative contacts. Derivative contacts in liability positions that were valued using quoted prices in active markets for identical instruments are exchange-traded interest rate and agricultural derivative contracts, net of cash margin. The fair value of financial assets and liabilities measured on a recurring basis was as follows as of December 31, 2016 (in thousands): Total Quoted Prices in Active Markets for Identical Instruments (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs Assets: Trading securities: U.S. government agency debentures $ 6,234 $ — $ 6,234 $ — U.S. government 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 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 1 247,073 — — 247,073 Derivative contracts, net of cash collateral 2 689,872 7,541 682,331 — Liabilities: Derivative contracts, net of cash collateral 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 6 , Mortgage Banking Activities. 2 See Note 3 for detail of fair value of derivative contracts by contract type. Derivative contracts based on quoted prices in active markets for identical instruments (Level 1) are exchange-traded interest-rate and energy derivative contacts, net of cash margin. Derivative contracts in liability positions 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 measured on a recurring basis was as follows as of June 30, 2016 (in thousands): Total Quoted Prices in Active Markets for Identical Instruments (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs Assets: Trading securities: U.S. government agency debentures $ 18,909 $ — $ 18,909 $ — U.S. government agency residential mortgage-backed securities 122,306 — 122,306 — Municipal and other tax-exempt securities 52,721 — 52,721 — Other trading securities 17,686 — 17,686 — Total trading securities 211,622 — 211,622 — Available for sale securities: U.S. Treasury 1,004 1,004 — — Municipal and other tax-exempt securities 50,262 — 40,662 9,600 U.S. government agency residential mortgage-backed securities 5,700,268 — 5,700,268 — Privately issued residential mortgage-backed securities 126,313 — 126,313 — Commercial mortgage-backed securities guaranteed by U.S. government agencies 2,911,946 — 2,911,946 — Other debt securities 4,151 — — 4,151 Perpetual preferred stock 17,931 — 17,931 — Equity securities and mutual funds 18,814 3,785 15,029 — Total available for sale securities 8,830,689 4,789 8,812,149 13,751 Fair value option securities: U.S. Treasury 25,306 25,306 — — U.S. government agency residential mortgage-backed securities 237,959 — 237,959 — Total fair value option securities 263,265 25,306 237,959 — Residential mortgage loans held for sale 430,728 — 420,979 9,749 Mortgage servicing rights 1 190,747 — — 190,747 Derivative contracts, net of cash collateral 2 883,673 7,246 876,427 — Liabilities: Derivative contracts, net of cash collateral 2 719,159 4,808 714,351 — 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 6 , Mortgage Banking Activities. 2 See Note 3 for detail of fair value of derivative contracts by contract type. Derivative contracts based on quoted prices in active markets for identical instruments (Level 1) are exchange-traded energy and agricultural derivative contacts, net of cash margin. Derivative contracts in liability positions that were valued using quoted prices in active markets for identical instruments (Level 1) are exchange-traded interest rate and energy derivative contracts, net 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 references 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 assesses 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. The reduction in fair value is recognized in earnings during the current period. 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 residential mortgage loans held for sale are based upon quoted market prices of such loans sold in securitization transactions, including related unfunded loan commitments and forward sales contracts. The fair value of mortgage loans that were unable to be sold to U.S. government agencies were 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 is 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 7 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 for the three and six months ended June 30, 2017 related to assets measured at fair value on a recurring basis using significant unobservable inputs (in thousands): Available for Sale Securities Municipal and other tax-exempt securities Other debt securities Residential mortgage loans held for sale Balance, March 31, 2017 $ 5,722 $ 4,153 $ 12,679 Transfer to Level 3 from Level 2 1 — — 853 Purchases — — — Proceeds from sales — — (1,030 ) Redemptions and distributions (1,100 ) — — Gain (loss) recognized in earnings: Mortgage banking revenue — — 233 Other comprehensive income (loss): Net change in unrealized gain (loss) 33 (1 ) — Balance, June 30, 2017 $ 4,655 $ 4,152 $ 12,735 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. Available for Sale Securities Municipal and other tax-exempt Other debt securities Residential mortgage loans held for sale Balance, Dec. 31, 2016 $ 5,789 $ 4,152 $ 11,617 Transfer to Level 3 from Level 2 1 — — 2,740 Purchases — — — Proceeds from sales — — (1,702 ) Redemptions and distributions (1,100 ) — — Gain (loss) recognized in earnings: Mortgage banking revenue — — 80 Other comprehensive income (loss): Net change in unrealized gain (loss) (34 ) — — Balance, June 30, 2017 $ 4,655 $ 4,152 $ 12,735 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. The following represents the changes for the three and six months ended June 30, 2016 related to assets measured at fair value on a recurring basis using significant unobservable inputs (in thousands): Available for Sale Securities Municipal and other tax-exempt securities Other debt securities Residential mortgage loans held for sale Balance, March 31, 2016 $ 9,614 $ 4,151 $ 8,099 Transfer to Level 3 from Level 2 1 — — 3,080 Purchases — — — Proceeds from sales — — (1,249 ) Redemptions and distributions — — — Gain (loss) recognized in earnings: Mortgage banking revenue — — (181 ) Other comprehensive income (loss): Net change in unrealized gain (loss) (14 ) — — Balance, June 30, 2016 $ 9,600 $ 4,151 $ 9,749 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. Available for Sale Securities Municipal and other tax-exempt Other debt securities Residential mortgage loans held for sale Balance, Dec. 31, 2015 $ 9,610 $ 4,151 $ 7,874 Transfer to Level 3 from Level 2 1 — — 3,540 Purchases — — — Proceeds from sales — — (1,362 ) Redemptions and distributions — — — Gain (loss) recognized in earnings Mortgage banking revenue — — (303 ) Other comprehensive income (loss): Net change in unrealized gain (loss) (10 ) — — Balance, June 30, 2016 $ 9,600 $ 4,151 $ 9,749 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 June 30, 2017 follows (in thousands): Par Value Amortized Cost/Unpaid Principal Balance Fair Value Valuation Technique(s) Unobservable Input Range (Weighted Average) Available for sale securities Municipal and other tax-exempt securities $ 5,095 $ 5,067 $ 4,655 Discounted cash flows 1 Interest rate spread 5.98%-5.98% (5.98%) 2 90.00%-94.90% (92.93%) 3 Other debt securities 4,400 4,400 4,152 Discounted cash flows 1 Interest rate spread 5.41%-6.72% (6.57%) 4 94.31% - 94.38 (94.37%) 3 Residential mortgage loans held for sale N/A 13,274 12,563 Quoted prices of loans sold in securitization transactions, with a liquidity discount applied Liquidity discount applied to the market value of a mortgage loans qualifying for sale to U.S. government agencies. 94.64% 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 360 to 446 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 3 percent . A summary of quantitative information about Recurring Fair Value Measurements based on Significant Unobservable Inputs (Level 3) as of December 31, 2016 follows (in thousands): Par Value Amortized Fair Value Valuation Technique(s) Unobservable Input Range (Weighted Average) Available for sale securities Municipal and other tax-exempt securities $ 6,195 $ 6,163 $ 5,789 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 a 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 less than 1 percent . A summary of quantitative information about Recurring Fair Value Measurements based on Significant Unobservable Inputs (Level 3) as of June 30, 2016 follows (in thousands): Par Value Amortized Cost Fair Value Valuation Technique(s) Unobservable Input Range (Weighted Average) Available for sale securities Municipal and other tax-exempt securities $ 10,370 $ 10,312 $ 9,600 Discounted cash flows 1 Interest rate spread 5.34%-5.64% (5.60%) 2 90.00%-93.28% (92.58%) 3 Other debt securities 4,400 4,400 4,151 Discounted cash flows 1 Interest rate spread 5.51%-5.96% (5.91%) 4 94.32% - 94.34 (94.34%) 3 Residential mortgage loans held for sale N/A 10,518 9,749 Quoted prices of loans sold in securitization transactions, with a liquidity discount applied Liquidity discount applied to the market value of a mortgage loans qualifying for sale to U.S. government agencies. 92.69% 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 474 to 513 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 percent . Fair Value of Assets and Liabilities Measured on a Non-Recurring Basis Assets measured at fair value on a non-recurring basis include 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. The following represents the carrying value of assets measured at fair value on a non-recurring basis (and related losses) during the period. The carrying value represents only those assets with a balance at June 30, 2017 for which the fair value was adjusted during the six months ended June 30, 2017 : Fair Value Adjustments for the Carrying Value at June 30, 2017 Three Months Ended Six Months Ended 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 Gross charge-offs against allowance for loan losses Net losses and expenses of repossessed assets, net Impaired loans $ — $ 464 $ 3,570 $ 232 $ — $ 676 $ — Real estate and other repossessed assets — 3,488 530 — 772 — 906 The following represents the carrying value of assets measured at fair value on a non-recurring basis (and related losses) during the period. The carrying value represents only those assets with a balance at June 30, 2016 for which the fair value was adjusted during the six months ended June 30, 2016 : Carrying Value at June 30, 2016 Fair Value Adjustments for the Three Months Ended Six Months Ended 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 Gross charge-offs against allowance for loan losses Net losses and expenses of repossessed assets, net Impaired loans $ — $ 634 $ 42,342 $ 7,041 $ — $ 29,186 $ — Real estate and other repossessed assets — 5,709 1,693 — 751 — 1,068 The fair value of collateral-dependent impaired loans secured by real estate 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 the same or 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 June 30, 2017 follows (in thousands): Fair Value Valuation Technique(s) Unobservable Input Range (Weighted Average) Impaired loans $ 3,570 Discounted cash flows Recoverable oil and gas reserves, forward-looking commodity prices, estimated operating costs 75% - 90% (83%) 1 Real estate and other repossessed assets 530 Appraised value, as adjusted Marketability adjustment off appraised value 2 65% - 88% (80%) 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 June 30, 2016 follows (in thousands): Fair Value Valuation Technique(s) Unobservable Input Range (Weighted Average) Impaired loans $ 42,342 Discounted cash flows Recoverable oil and gas reserves, forward-looking commodity prices, estimated operating costs 25% - 71% (58%) 1 Real estate and other repossessed assets 1,693 Appraised value, as adjusted Marketability adjustments off appraised value2 68% - 80% (71%) 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. 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 basis as of June 30, 2017 (dollars in thousands): Carrying Value Estimated Fair Value Quoted Prices in Active Markets for Identical Instruments (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs Cash and due from banks $ 561,587 $ 561,587 $ 561,587 $ — $ — Interest-bearing cash and cash equivalents 2,078,831 2,078,831 2,078,831 — — Trading securities: — U.S. government agency debentures 20,954 20,954 — 20,954 — U.S. government agency residential mortgage-backed securities 365,171 365,171 — 365,171 — Municipal and other tax-exempt securities 45,444 45,444 — 45,444 — Other trading securities 9,845 9,845 — 9,845 — Total trading securities 441,414 441,414 — 441,414 — Investment securities: Municipal and other tax-exempt securities 267,375 270,531 — 270,531 — U.S. government agency residential mortgage-backed securities 18,035 18,642 — 18,642 — Other debt securities 205,016 226,502 — 226,502 — Total investment securities 490,426 515,675 — 515,675 — Available for sale securities: U.S. Treasury 998 998 998 — — Municipal and other tax-exempt securities 32,765 32,765 — 28,110 4,655 U.S. government agency residential mortgage-backed securities 5,382,377 5,382,377 — 5,382,377 — Privately issued residential mortgage-backed securities 103,383 103,383 — 103,383 — Commercial mortgage-backed securities guaranteed by U.S. government agencies 2,782,070 2,782,070 — 2,782,070 — Other debt securities 4,152 4,152 — — 4,152 Perpetual preferred stock 16,568 16,568 — 16,568 — Equity securities and mutual funds 18,728 18,728 3,516 15,212 — Total available for sale securities 8,341,041 8,341,041 4,514 8,327,720 8,807 Fair value option securities – U.S. government agency residential mortgage-backed securities 445,169 445,169 — 445,169 — Residential mortgage loans held for sale 287,259 287,259 — 274,524 12,735 Loans: Commercial 10,637,955 10,413,704 — — 10,413,704 Commercial real estate 3,688,592 3,636,365 — — 3,636,365 Residential mortgage 1,939,198 1,950,577 — — 1,950,577 Personal 917,900 909,055 — — 909,055 Total loans 17,183,645 16,909,701 — — 16,909,701 Allowance for loan losses (250,061 ) — — — — Loans, net of allowance 16,933,584 16,909,701 — — 16,909,701 Mortgage servicing rights 245,239 245,239 — — 245,239 Derivative instruments with positive fair value, net of cash collateral 280,289 280,289 46,366 233,923 — Deposits with no stated maturity 20,120,352 20,120,352 — — 20,120,352 Time deposits 2,196,122 2,164,115 — — 2,164,115 Other borrowed funds 5,696,666 5,664,273 — — 5,664,273 Subordinated debentures 144,658 147,204 — 147,204 — Derivative instruments with negative fair value, net of cash collateral 285,819 285,819 20,915 264,904 — 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 basis as of December 31, 2016 (dollars in thousands): Carrying Value Estimated Fair Value Quoted Prices in Active Markets for Identical Instruments (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs 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 33

Federal and State Income Taxes

Federal and State Income Taxes Federal and State Income Taxes	6 Months Ended
	Jun. 30, 2017
Income Tax Disclosure [Abstract]
Income Tax Disclosure [Text Block]	Federal and State Income Taxes The reconciliations of income (loss) attributable to continuing operations at the U.S. federal statutory tax rate to income tax expense are as follows (in thousands): Three Months Ended Six Months Ended 2017 2016 2017 2016 Amount: Federal statutory tax $ 47,800 $ 33,869 $ 92,168 $ 55,715 Tax exempt revenue (3,224 ) (2,568 ) (6,335 ) (5,100 ) Effect of state income taxes, net of federal benefit 2,944 1,557 5,389 3,858 Utilization of tax credits: Low-income housing tax credit, net of amortization (526 ) (572 ) (2,249 ) (1,882 ) Other tax credits (363 ) (521 ) (727 ) (1,042 ) Bank-owned life insurance (775 ) (810 ) (1,547 ) (1,601 ) Share-based compensation 1,636 — (2,301 ) — Other, net 213 (458 ) 1,410 1,977 Total income tax expense $ 47,705 $ 30,497 $ 85,808 $ 51,925 Three Months Ended Six Months Ended 2017 2016 2017 2016 Percent of pretax income: Federal statutory tax 35.0 % 35.0 % 35.0 % 35.0 % Tax exempt revenue (2.4 ) (2.7 ) (2.4 ) (3.2 ) Effect of state income taxes, net of federal benefit 2.2 1.6 2.0 2.4 Utilization of tax credits: Low-income housing tax credit, net of amortization (0.4 ) (0.6 ) (0.8 ) (1.2 ) Other tax credits (0.3 ) (0.5 ) (0.3 ) (0.6 ) Bank-owned life insurance (0.6 ) (0.8 ) (0.6 ) (1.0 ) Share-based compensation 1.2 — (0.9 ) — Other, net 0.2 (0.5 ) 0.6 1.2 Total 34.9 % 31.5 % 32.6 % 32.6 %

Subsequent Events

Subsequent Events	6 Months Ended
	Jun. 30, 2017
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events The Company evaluated events from the date of the consolidated financial statements on June 30, 2017 through the issuance of those consolidated financial statements included in this Quarterly Report on Form 10-Q. No events were identified requiring recognition in and/or disclosure in the consolidated financial statements.

Significant Accounting Polici21

Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 30, 2017
Accounting Policies [Abstract]
Basis of Accounting, Policy [Policy Text Block]	The accompanying unaudited consolidated financial statements of BOK Financial Corporation (“BOK Financial” or “the Company”) have been prepared in accordance with accounting principles for interim financial information generally accepted in the United States and with the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the information and footnotes required by generally accepted accounting principles for complete financial statements. In the opinion of management, all adjustments (consisting of normal recurring accruals) considered necessary for a fair presentation have been included.
Principles of Consolidation [Policy Text Block]	The unaudited consolidated financial statements include accounts of BOK Financial and its subsidiaries, principally BOKF, NA (“the Bank”), BOK Financial Securities, Inc., The Milestone Group, Inc. and Cavanal Hill Investment Management Inc. Operating divisions of the Bank include Bank of Albuquerque, Bank of Arizona, Bank of Arkansas, Bank of Oklahoma, Bank of Texas, Colorado State Bank and Trust, Mobank, BOK Financial Mortgage and the TransFund electronic funds network.
Reclassification, Policy [Policy Text Block]	Certain reclassifications have been made to conform to the current period presentation.
Newly Adopted and Pending Accounting Policies [Policy Text Block]	Newly Adopted and Pending Accounting Policies 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 commissions 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 represents 19% of gross revenue and 43% of fees and commissions revenue for the first half of 2017. Timing of revenue recognition and gross versus net presentation may be affected. Management will 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 is evaluating the impact the adoption of ASU 2016-08 will have on the Company's financial statements along with ASU 2014-09. 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 over the recognition and measurement of financial assets and liabilities. The update 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. At June 30, 2017 , the Company had $3.2 million of unrealized gains included in accumulated 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 lease assets and 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 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. 2016-09, 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 became effective for annual reporting periods beginning after December 15, 2016, including interim periods within those annual reporting periods. Implementation of ASU 2016-09 decreased tax expense $2.3 million in the first six months of 2017. 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 in order to provide more timely recording of credit losses on loans and other financial instruments. The ASU adds 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 a 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 guidance in ASC 230 on the classification of certain cash receipts and payments in the statement of cash flows. The amendments address eight cash flow issues. ASU 2016-15 is effective for the Company for interim and annual reporting periods beginning after December 15, 2017. 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.
Derivatives, Policy [Policy Text Block]	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 reported in earnings as they occur. Credit risk is also considered in determining fair value. When bilateral netting agreements or similar arrangements 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 type by counterparty basis. Derivative contracts may 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. None of these derivative contracts have been designated as hedging instruments for accounting purposes. Customer Risk Management Programs BOK Financial offers programs to permit its customers to manage various risks, including fluctuations in energy, cattle and other agricultural products, interest rates and foreign exchange rates with derivative contracts. Customers may also manage interest rate risk through interest rate swaps used by borrowers to modify interest rate terms of their loans or to-be-announced securities used by 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 the risk of 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. Internal Risk Management Programs BOK Financial may use derivative contracts in managing its interest rate sensitivity, as part of its economic hedge of the change in the fair value of mortgage servicing rights and as an economic hedge of trading securities. As of June 30, 2017 , derivative contracts under the internal risk management programs were primarily used as part of the economic hedges of the change in the fair value of the mortgage servicing rights and trading securities. As discussed in Note 6 , 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 6 for additional discussion of notional, fair value and impact on earnings of these contracts.
Loans and Allowances for Credit Losses, 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 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 mortgage loans guaranteed by U.S. government agencies, are as follows. Interest is accrued at the applicable interest rate on the principal amount outstanding. 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 more than 90 days 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 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, excluding loans guaranteed by U.S. government agencies. 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 value, debt service ratio and other underwriting standards. Nonaccruing loans may be renewed and will remain classified as nonaccruing. 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 a quarterly evaluation of available cash resources and collateral value 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. 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 may have 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 Sheets. Guaranteed loans are considered 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 the 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 based on the modified rate. 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 credit losses. Classes are a further disaggregation of portfolio segments based on the risk characteristics of the loans and the Company’s method for monitoring and assessing credit risk.
Loans and Allowances for Credit Losses, Allowances for Credit Losses [Policy Text Block]	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 6 , the Company also has separate accruals for 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 appropriateness of the allowance for loan losses and accrual for off-balance sheet credit losses (collectively "allowance for credit losses") is assessed by management based on an ongoing quarterly evaluation of the probable estimated losses inherent in the portfolio, including probable losses on both outstanding loans and unused commitments. 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, risk concentration and related factors. There have been no material changes in the approach or techniques utilized in developing the allowance for loan losses and the accrual for off-balance sheet credit losses for the three and six months ended June 30, 2017 . 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 consumer loans are risk graded based on evaluation of the borrowers' ability to repay. Certain commercial loans and most residential mortgage and consumer 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 or modified in a TDR 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 loans’ initial effective interest rate or the fair value of collateral for certain collateral dependent loans. Collateral value of real property 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 are generally not adjusted by the Company. Updated appraisals are obtained at least annually or more frequently if market conditions indicate collateral values have declined. Collateral value of mineral rights is generally determined by our internal staff of engineers based on projected 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 updated 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 estimated loss rates by loan class. The gross loss rate for each loan class is determined by the greater of the current gross loss rate based on the most recent twelve months or a ten-year gross loss rate. Recoveries are not directly considered in the estimation of 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, 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 average risk grade. This comparison determines whether credit risk in each loan class is increasing or decreasing. 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 specific loan classes which have not yet been represented in the 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 loan or loan class. These factors include trends in the economy of our primary lending areas, concentrations in large balance loans and other relevant factors. An accrual for off-balance sheet credit losses is included in Other liabilities in the Consolidated Balance Sheets. The appropriateness of this 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.

Securities (Tables)

Securities (Tables)	6 Months Ended
	Jun. 30, 2017
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): June 30, 2017 December 31, 2016 June 30, 2016 Fair Value Net Unrealized Gain (Loss) Fair Value Net Unrealized Gain (Loss) Fair Value Net Unrealized Gain (Loss) U.S. government agency debentures $ 20,954 $ (9 ) $ 6,234 $ (4 ) $ 18,909 $ (8 ) U.S. government agency residential mortgage-backed securities 365,171 (1,032 ) 310,067 635 122,306 363 Municipal and other tax-exempt securities 45,444 230 14,427 50 52,721 262 Other trading securities 9,845 (175 ) 6,900 57 17,686 169 Total trading securities $ 441,414 $ (986 ) $ 337,628 $ 738 $ 211,622 $ 786
Investment Securities (Held-to-Maturity) [Table Text Block]	The amortized cost and fair values of investment securities are as follows (in thousands): June 30, 2017 Amortized Fair Gross Unrealized 1 Cost Value Gain Loss Municipal and other tax-exempt $ 267,375 $ 270,531 $ 3,384 $ (228 ) U.S. government agency residential mortgage-backed securities – Other 18,035 18,642 668 (61 ) Other debt securities 205,016 226,502 22,040 (554 ) Total investment securities $ 490,426 $ 515,675 $ 26,092 $ (843 ) 1 Gross unrealized gains and losses are not recognized in Accumulated Other Comprehensive Income "AOCI" in the Consolidated Balance Sheets. December 31, 2016 Amortized Fair Gross Unrealized 1 Cost Value Gain Loss Municipal and other tax-exempt $ 320,364 $ 321,225 $ 2,272 $ (1,411 ) U.S. government agency residential mortgage-backed securities – Other 20,777 21,473 767 (71 ) Other debt securities 205,004 222,795 18,115 (324 ) Total investment securities $ 546,145 $ 565,493 $ 21,154 $ (1,806 ) 1 Gross unrealized gains and losses are not recognized in AOCI in the Consolidated Balance Sheets. June 30, 2016 Amortized Fair Gross Unrealized 1 Cost Value Gain Loss Municipal and other tax-exempt $ 334,551 $ 340,700 $ 6,234 $ (85 ) U.S. government agency residential mortgage-backed securities – Other 23,750 25,233 1,483 — Other debt securities 202,410 233,129 30,723 (4 ) Total investment securities $ 560,711 $ 599,062 $ 38,440 $ (89 ) 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 June 30, 2017 , 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: Amortized cost $ 90,415 $ 122,560 $ 10,739 $ 43,661 $ 267,375 3.48 Fair value 90,436 122,914 11,220 45,961 270,531 Nominal yield¹ 1.66 % 2.12 % 4.88 % 5.05 % 2.55 % Other debt securities: Amortized cost 14,286 45,638 130,279 14,813 205,016 6.59 Fair value 14,482 48,973 148,415 14,632 226,502 Nominal yield 3.84 % 4.95 % 5.75 % 4.46 % 5.35 % Total fixed maturity securities: Amortized cost $ 104,701 $ 168,198 $ 141,018 $ 58,474 $ 472,391 4.83 Fair value 104,918 171,887 159,635 60,593 497,033 Nominal yield 1.95 % 2.89 % 5.69 % 4.90 % 3.77 % Residential mortgage-backed securities: Amortized cost $ 18,035 ³ Fair value 18,642 Nominal yield 4 2.76 % Total investment securities: Amortized cost $ 490,426 Fair value 515,675 Nominal yield 3.73 % 1 Calculated on a taxable equivalent basis using a 39 percent 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): June 30, 2017 Amortized Fair Gross Unrealized 1 Cost Value Gain Loss OTTI ² U.S. Treasury $ 1,000 $ 998 $ — $ (2 ) $ — Municipal and other tax-exempt 32,885 32,765 293 (413 ) — Residential mortgage-backed securities: U. S. government agencies: FNMA 3,005,920 3,008,531 24,213 (21,602 ) — FHLMC 1,412,376 1,412,472 7,785 (7,689 ) — GNMA 938,086 936,365 3,641 (5,362 ) — Other 25,000 25,009 52 (43 ) — Total U.S. government agencies 5,381,382 5,382,377 35,691 (34,696 ) — Private issue: Alt-A loans 38,334 46,903 8,569 — — Jumbo-A loans 48,322 56,480 8,158 — — Total private issue 86,656 103,383 16,727 — — Total residential mortgage-backed securities 5,468,038 5,485,760 52,418 (34,696 ) — Commercial mortgage-backed securities guaranteed by U.S. government agencies 2,788,543 2,782,070 7,804 (14,277 ) — Other debt securities 4,400 4,152 — (248 ) — Perpetual preferred stock 12,562 16,568 4,006 — — Equity securities and mutual funds 17,572 18,728 1,219 (63 ) — Total available for sale securities $ 8,325,000 $ 8,341,041 $ 65,740 $ (49,699 ) $ — 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, 2016 Amortized Fair Gross Unrealized¹ Cost Value Gain Loss OTTI ² U.S. Treasury $ 1,000 $ 999 $ — $ (1 ) $ — Municipal and other tax-exempt 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. June 30, 2016 Amortized Fair Gross Unrealized 1 Cost Value Gain Loss OTTI ² U.S. Treasury $ 1,000 $ 1,004 $ 4 $ — $ — Municipal and other tax-exempt 50,170 50,262 805 (713 ) — Residential mortgage-backed securities: U. S. government agencies: FNMA 2,908,698 2,988,974 80,549 (273 ) — FHLMC 1,746,661 1,785,332 38,869 (198 ) — GNMA 921,928 925,962 4,646 (612 ) — Total U.S. government agencies 5,577,287 5,700,268 124,064 (1,083 ) — Private issue: Alt-A loans 49,522 54,536 5,461 — (447 ) Jumbo-A loans 65,787 71,777 6,355 (36 ) (329 ) Total private issue 115,309 126,313 11,816 (36 ) (776 ) Total residential mortgage-backed securities 5,692,596 5,826,581 135,880 (1,119 ) (776 ) Commercial mortgage-backed securities guaranteed by U.S. government agencies 2,854,306 2,911,946 57,762 (122 ) — Other debt securities 4,400 4,151 — (249 ) — Perpetual preferred stock 15,562 17,931 2,369 — — Equity securities and mutual funds 17,270 18,814 1,558 (14 ) — Total available for sale securities $ 8,635,304 $ 8,830,689 $ 198,378 $ (2,217 ) $ (776 ) 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 June 30, 2017 , 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. Treasuries: Amortized cost $ 1,000 $ — $ — $ — $ 1,000 0.55 Fair value 998 — — — 998 Nominal yield 0.87 % — % — % — % 0.87 % Municipal and other tax-exempt: Amortized cost $ 8,981 $ 6,380 $ 1,028 $ 16,496 $ 32,885 8.87 Fair value 9,021 6,497 1,081 16,166 32,765 Nominal yield¹ 4.24 % 3.91 % 6.72 % 2.28 % 6 3.27 % Commercial mortgage-backed securities: Amortized cost $ 58,263 $ 880,459 $ 1,571,735 $ 278,086 $ 2,788,543 6.98 Fair value 58,147 879,286 1,568,732 275,905 2,782,070 Nominal yield 1.20 % 1.83 % 1.84 % 1.88 % 1.82 % Other debt securities: Amortized cost $ — $ — $ — $ 4,400 $ 4,400 30.16 Fair value — — — 4,152 4,152 Nominal yield — % — % — % 1.71 % 6 1.71 % Total fixed maturity securities: Amortized cost $ 68,244 $ 886,839 $ 1,572,763 $ 298,982 $ 2,826,828 7.03 Fair value 68,166 885,783 1,569,813 296,223 2,819,985 Nominal yield 1.60 % 1.85 % 1.85 % 1.90 % 1.83 % Residential mortgage-backed securities: Amortized cost $ 5,468,038 2 Fair value 5,485,760 Nominal yield 4 1.94 % Equity securities and mutual funds: Amortized cost $ 30,134 ³ Fair value 35,296 Nominal yield — % Total available-for-sale securities: Amortized cost $ 8,325,000 Fair value 8,341,041 Nominal yield 1.90 % 1 Calculated on a taxable equivalent basis using a 39 percent effective tax rate. 2 The average expected lives of mortgage-backed securities were 3.9 years 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): Three Months Ended Six Months Ended 2017 2016 2017 2016 Proceeds $ 460,402 $ 325,758 $ 700,412 $ 795,140 Gross realized gains 2,763 5,326 4,855 9,290 Gross realized losses (2,383 ) — (2,426 ) — Related federal and state income tax expense 148 2,072 945 3,614
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): June 30, 2017 Dec. 31, 2016 June 30, 2016 Investment: Amortized cost $ 251,684 $ 322,208 $ 287,166 Fair value 255,097 323,808 293,625 Available for sale: Amortized cost 6,327,666 7,353,116 7,502,361 Fair value 6,317,623 7,327,470 7,657,916
Schedule of Unrealized Loss on Investments [Table Text Block]	Temporarily Impaired Securities as of June 30, 2017 (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 82 $ 111,078 $ 149 $ 3,000 $ 79 $ 114,078 $ 228 U.S. government agency residential mortgage-backed securities – Other 1 3,810 61 — — 3,810 61 Other debt securities 22 8,384 554 — — 8,384 554 Total investment securities 105 $ 123,272 $ 764 $ 3,000 $ 79 $ 126,272 $ 843 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 1 $ 997 $ 2 $ — $ — $ 997 $ 2 Municipal and other tax-exempt 13 $ 1,957 $ 1 $ 4,655 $ 412 $ 6,612 $ 413 Residential mortgage-backed securities: U. S. government agencies: FNMA 75 1,381,687 20,288 87,371 1,314 1,469,058 21,602 FHLMC 42 731,853 7,213 16,388 476 748,241 7,689 GNMA 21 291,806 3,766 76,605 1,596 368,411 5,362 Other 1 19,957 43 — — 19,957 43 Total U.S. government agencies 139 2,425,303 31,310 180,364 3,386 2,605,667 34,696 Private issue: Alt-A loans — — — — — — — Jumbo-A loans — — — — — — — Total private issue — — — — — — — Total residential mortgage-backed securities 139 2,425,303 31,310 180,364 3,386 2,605,667 34,696 Commercial mortgage-backed securities guaranteed by U.S. government agencies 121 1,388,406 12,690 78,828 1,587 1,467,234 14,277 Other debt securities 2 — — 4,152 248 4,152 248 Perpetual preferred stocks — — — — — — — Equity securities and mutual funds 91 1,668 22 887 41 2,555 63 Total available for sale securities 367 $ 3,818,331 $ 44,025 $ 268,886 $ 5,674 $ 4,087,217 $ 49,699 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 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 1 $ 999 $ 1 $ — $ — $ 999 $ 1 Municipal and other tax-exempt 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. government 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 stocks — — — — — — — 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 June 30, 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 19 $ 11,915 $ 20 $ 4,378 $ 65 $ 16,293 $ 85 U.S. government agency residential mortgage-backed securities – Other — — — — — — — Other debt securities 1 — — 858 4 858 4 Total investment securities 20 $ 11,915 $ 20 $ 5,236 $ 69 $ 17,151 $ 89 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 — $ — $ — $ — $ — $ — $ — Municipal and other tax-exempt 1 17 $ 375 $ — $ 10,289 $ 713 $ 10,664 $ 713 Residential mortgage-backed securities: U. S. government agencies: FNMA 4 97,910 267 15,401 6 113,311 273 FHLMC 1 — — 22,338 198 22,338 198 GNMA 11 349,631 612 — — 349,631 612 Total U.S. government agencies 16 447,541 879 37,739 204 485,280 1,083 Private issue 1 : Alt-A loans 5 8,513 241 8,291 206 16,804 447 Jumbo-A loans 9 7,076 36 7,877 329 14,953 365 Total private issue 14 15,589 277 16,168 535 31,757 812 Total residential mortgage-backed securities 30 463,130 1,156 53,907 739 517,037 1,895 Commercial mortgage-backed securities guaranteed by U.S. government agencies 11 103,955 37 65,857 85 169,812 122 Other debt securities 2 — — 4,151 249 4,151 249 Perpetual preferred stocks — — — — — — — Equity securities and mutual funds 30 — — 889 14 889 14 Total available for sale securities 90 $ 567,460 $ 1,193 $ 135,093 $ 1,800 $ 702,553 $ 2,993 1 Includes securities for which an unrealized loss remains in AOCI after an other-than-temporary credit loss has been recognized in income.
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): June 30, 2017 Dec. 31, 2016 June 30, 2016 Fair Value Net Unrealized Gain (Loss) Fair Value Net Unrealized Gain (Loss) Fair Value Net Unrealized Gain (Loss) U.S. Treasury $ — $ — $ — $ — $ 25,306 $ (43 ) U.S. government agency residential mortgage-backed securities 445,169 1,247 77,046 (1,777 ) 237,959 4,476 Total $ 445,169 $ 1,247 $ 77,046 $ (1,777 ) $ 263,265 $ 4,433
Schedule of Restricted Equity Securities [Table Text Block]	June 30, 2017 Dec. 31, 2016 June 30, 2016 Federal Reserve stock $ 36,676 $ 36,498 $ 36,283 Federal Home Loan Bank stock 274,113 270,541 283,155 Other 244 201 201 Total $ 311,033 $ 307,240 $ 319,639

Derivatives (Tables)

Derivatives (Tables)	6 Months Ended
	Jun. 30, 2017
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 June 30, 2017 (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 $ 16,174,687 $ 57,948 $ (29,034 ) $ 28,914 $ — $ 28,914 Interest rate swaps 1,450,193 29,932 — 29,932 (2,206 ) 27,726 Energy contracts 891,480 56,824 (20,546 ) 36,278 (21,267 ) 15,011 Agricultural contracts 45,250 3,541 (1,027 ) 2,514 — 2,514 Foreign exchange contracts 169,529 162,429 — 162,429 (7 ) 162,422 Equity option contracts 100,159 4,437 — 4,437 (920 ) 3,517 Total customer risk management programs 18,831,298 315,111 (50,607 ) 264,504 (24,400 ) 240,104 Internal risk management programs 10,680,498 40,185 — 40,185 — 40,185 Total derivative contracts $ 29,511,796 $ 355,296 $ (50,607 ) $ 304,689 $ (24,400 ) $ 280,289 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 $ 16,174,687 $ 53,829 $ (29,034 ) $ 24,795 $ — $ 24,795 Interest rate swaps 1,450,193 29,982 — 29,982 (15,396 ) 14,586 Energy contracts 874,625 53,895 (20,546 ) 33,349 — 33,349 Agricultural contracts 45,262 3,538 (1,027 ) 2,511 (2,511 ) — Foreign exchange contracts 169,553 162,276 — 162,276 (3,188 ) 159,088 Equity option contracts 100,159 4,437 — 4,437 — 4,437 Total customer risk management programs 18,814,479 307,957 (50,607 ) 257,350 (21,095 ) 236,255 Internal risk management programs 8,310,950 49,564 — 49,564 — 49,564 Total derivative contracts $ 27,125,429 $ 357,521 $ (50,607 ) $ 306,914 $ (21,095 ) $ 285,819 1 Notional amounts for commodity contracts are converted into dollar-equivalent amounts based on dollar prices at the inception of the contract. 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 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 $ 16,637,532 $ 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. The following table summarizes the fair values of derivative contracts recorded as “derivative contracts” assets and liabilities in the balance sheet at June 30, 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 $ 18,774,134 $ 183,118 $ (67,383 ) $ 115,735 $ — $ 115,735 Interest rate swaps 1,299,985 54,978 — 54,978 (1,100 ) 53,878 Energy contracts 757,669 59,103 (33,996 ) 25,107 (155 ) 24,952 Agricultural contracts 50,848 2,488 (1,609 ) 879 (37 ) 842 Foreign exchange contracts 701,436 675,804 — 675,804 (5,054 ) 670,750 Equity option contracts 116,901 4,236 — 4,236 (478 ) 3,758 Total customer risk management programs 21,700,973 979,727 (102,988 ) 876,739 (6,824 ) 869,915 Internal risk management programs 1,337,000 13,758 — 13,758 — 13,758 Total derivative contracts $ 23,037,973 $ 993,485 $ (102,988 ) $ 890,497 $ (6,824 ) $ 883,673 Liabilities 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 $ 18,662,334 $ 179,443 $ (67,383 ) $ 112,060 $ (103,724 ) $ 8,336 Interest rate swaps 1,299,985 55,404 — 55,404 (32,597 ) 22,807 Energy contracts 734,538 58,033 (33,996 ) 24,037 (11,784 ) 12,253 Agricultural contracts 50,843 2,476 (1,609 ) 867 — 867 Foreign exchange contracts 701,219 675,383 — 675,383 (4,723 ) 670,660 Equity option contracts 116,901 4,236 — 4,236 — 4,236 Total customer risk management programs 21,565,820 974,975 (102,988 ) 871,987 (152,828 ) 719,159 Internal risk management programs — — — — — — Total derivative contracts $ 21,565,820 $ 974,975 $ (102,988 ) $ 871,987 $ (152,828 ) $ 719,159 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 income statement (in thousands): Three Months Ended June 30, 2017 June 30, 2016 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 $ 9,205 $ — $ 9,862 $ — Interest rate swaps 665 — 723 — Energy contracts 1,666 — 2,749 — Agricultural contracts 11 — 32 — Foreign exchange contracts 90 — 134 — Equity option contracts — — — — Total customer risk management programs 11,637 — 13,500 — Internal risk management programs 6,485 3,241 (9 ) 10,766 Total derivative contracts $ 18,122 $ 3,241 $ 13,491 $ 10,766 Six Months Ended June 30, 2017 June 30, 2016 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 $ 17,232 $ — $ 17,302 $ — Interest rate swaps 1,124 — 1,048 — Energy contracts 4,539 — 3,445 — Agricultural contracts 20 — 61 — Foreign exchange contracts 360 — 512 — Equity option contracts — — — — Total customer risk management programs 23,275 — 22,368 — Internal risk management programs 6,018 2,791 (9 ) 17,904 Total derivative contracts $ 29,293 $ 2,791 $ 22,359 $ 17,904

Loans and Allowances for Cred24

Loans and Allowances for Credit Losses (Tables)	6 Months Ended
	Jun. 30, 2017
Loans Receivable, Net [Abstract]
Schedule of Loans by Portfolio Segment [Table Text Block]	Portfolio segments of the loan portfolio are as follows (in thousands): June 30, 2017 December 31, 2016 Fixed Rate Variable Rate Non-accrual Total Fixed Rate Variable Rate Non-accrual Total Commercial $ 2,198,066 $ 8,242,732 $ 197,157 $ 10,637,955 $ 2,327,085 $ 7,884,786 $ 178,953 $ 10,390,824 Commercial real estate 594,542 3,090,275 3,775 3,688,592 624,187 3,179,338 5,521 3,809,046 Residential mortgage 1,597,587 297,376 44,235 1,939,198 1,647,357 256,255 46,220 1,949,832 Personal 150,728 766,900 272 917,900 154,971 684,697 290 839,958 Total $ 4,540,923 $ 12,397,283 $ 245,439 $ 17,183,645 $ 4,753,600 $ 12,005,076 $ 230,984 $ 16,989,660 Accruing loans past due (90 days) 1 $ 1,414 $ 5 June 30, 2016 Fixed Rate Variable Rate Non-accrual Total Commercial $ 1,994,415 $ 8,180,033 $ 181,989 $ 10,356,437 Commercial real estate 612,822 2,961,364 7,780 3,581,966 Residential mortgage 1,586,116 237,746 57,061 1,880,923 Personal 109,447 477,622 354 587,423 Total $ 4,302,800 $ 11,856,765 $ 247,184 $ 16,406,749 Accruing loans past due (90 days) 1 $ 2,899 1 Excludes residential mortgage loans guaranteed by agencies of the U.S. government
Rollforward of Allowance For Loan Losses And Accrual for Off-Balance Sheet Credit Losses [Table Text Block]	The activity in the allowance for loan losses and the allowance for off-balance sheet credit losses related to loan commitments and standby letters of credit for the three months ended June 30, 2017 is summarized as follows (in thousands): Commercial Commercial Real Estate Residential Mortgage Personal Nonspecific Allowance Total Allowance for loan losses: Beginning balance $ 137,616 $ 58,343 $ 18,177 $ 7,247 $ 27,327 $ 248,710 Provision for loan losses 1,546 105 (47 ) 1,358 47 3,009 Loans charged off (1,703 ) (76 ) (40 ) (1,053 ) — (2,872 ) Recoveries 283 208 169 554 — 1,214 Ending balance $ 137,742 $ 58,580 $ 18,259 $ 8,106 $ 27,374 $ 250,061 Allowance for off-balance sheet credit losses: Beginning balance $ 9,288 $ 106 $ 40 $ 6 $ — $ 9,440 Provision for off-balance sheet credit losses (2,987 ) (22 ) (2 ) 2 — (3,009 ) Ending balance $ 6,301 $ 84 $ 38 $ 8 $ — $ 6,431 Total provision for credit losses $ (1,441 ) $ 83 $ (49 ) $ 1,360 $ 47 $ — The activity in the allowance for loan losses and the allowance for off-balance sheet credit losses related to loan commitments and standby letters of credit for the six months ended June 30, 2017 is summarized as follows (in thousands): Commercial Commercial Real Estate Residential Mortgage Personal Nonspecific Allowance Total Allowance for loan losses: Beginning balance $ 140,213 $ 50,749 $ 18,224 $ 8,773 $ 28,200 $ 246,159 Provision for loan losses (1,809 ) 6,964 (86 ) 570 (826 ) 4,813 Loans charged off (2,127 ) (76 ) (276 ) (2,546 ) — (5,025 ) Recoveries 1,465 943 397 1,309 — 4,114 Ending balance $ 137,742 $ 58,580 $ 18,259 $ 8,106 $ 27,374 $ 250,061 Allowance for off-balance sheet credit losses: Beginning balance $ 11,063 $ 123 $ 50 $ 8 $ — $ 11,244 Provision for off-balance sheet credit losses (4,762 ) (39 ) (12 ) — — (4,813 ) Ending balance $ 6,301 $ 84 $ 38 $ 8 $ — $ 6,431 Total provision for credit losses $ (6,571 ) $ 6,925 $ (98 ) $ 570 $ (826 ) $ — The activity in the allowance for loan losses and the allowance for off-balance sheet credit losses related to loan commitments and standby letters of credit for the three months ended June 30, 2016 is summarized as follows (in thousands): Commercial Commercial Real Estate Residential Mortgage Personal Nonspecific Allowance Total Allowance for loan losses: Beginning balance $ 139,793 $ 44,453 $ 18,467 $ 5,022 $ 25,421 $ 233,156 Provision for loan losses 12,478 2,010 368 1,443 1,263 17,562 Loans charged off (7,355 ) — (345 ) (1,145 ) — (8,845 ) Recoveries 223 282 200 681 — 1,386 Ending balance $ 145,139 $ 46,745 $ 18,690 $ 6,001 $ 26,684 $ 243,259 Allowance for off-balance sheet credit losses: Beginning balance $ 6,319 $ 228 $ 58 $ 2 $ — $ 6,607 Provision for off-balance sheet credit losses 2,433 (25 ) 4 26 — 2,438 Ending balance $ 8,752 $ 203 $ 62 $ 28 $ — $ 9,045 Total provision for credit losses $ 14,911 $ 1,985 $ 372 $ 1,469 $ 1,263 $ 20,000 The activity in the allowance for loan losses and the allowance for off-balance sheet credit losses related to loan commitments and standby letters of credit for the six months ended June 30, 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 43,575 4,987 (363 ) 2,909 (3,442 ) 47,666 Loans charged off (29,481 ) — (819 ) (2,536 ) — (32,836 ) Recoveries 711 367 363 1,464 — 2,905 Ending balance $ 145,139 $ 46,745 $ 18,690 $ 6,001 $ 26,684 $ 243,259 Allowance for off-balance sheet credit losses: Beginning balance $ 1,506 $ 153 $ 30 $ 22 $ — $ 1,711 Provision for off-balance sheet credit losses 7,246 50 32 6 — 7,334 Ending balance $ 8,752 $ 203 $ 62 $ 28 $ — $ 9,045 Total provision for credit losses $ 50,821 $ 5,037 $ (331 ) $ 2,915 $ (3,442 ) $ 55,000 The allowance for loan losses and recorded investment of the related loans by portfolio segment for each impairment measurement method at June 30, 2017 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 $ 10,440,798 $ 128,049 $ 197,157 $ 9,693 $ 10,637,955 $ 137,742 Commercial real estate 3,684,817 58,580 3,775 — 3,688,592 58,580 Residential mortgage 1,894,963 18,259 44,235 — 1,939,198 18,259 Personal 917,628 8,106 272 — 917,900 8,106 Total 16,938,206 212,994 245,439 9,693 17,183,645 222,687 Nonspecific allowance — — — — — 27,374 Total $ 16,938,206 $ 212,994 $ 245,439 $ 9,693 $ 17,183,645 $ 250,061 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 June 30, 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 $ 10,174,448 $ 140,911 $ 181,989 $ 4,228 $ 10,356,437 $ 145,139 Commercial real estate 3,574,186 46,727 7,780 18 3,581,966 46,745 Residential mortgage 1,823,862 18,626 57,061 64 1,880,923 18,690 Personal 587,069 6,001 354 — 587,423 6,001 Total 16,159,565 212,265 247,184 4,310 16,406,749 216,575 Nonspecific allowance — — — — — 26,684 Total $ 16,159,565 $ 212,265 $ 247,184 $ 4,310 $ 16,406,749 $ 243,259
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 June 30, 2017 is as follows (in thousands): Internally Risk Graded Non-Graded Total Recorded Investment Related Allowance Recorded Investment Related Allowance Recorded Investment Related Allowance Commercial $ 10,612,477 $ 136,819 $ 25,478 $ 923 $ 10,637,955 $ 137,742 Commercial real estate 3,688,592 58,580 — — 3,688,592 58,580 Residential mortgage 216,007 2,976 1,723,191 15,283 1,939,198 18,259 Personal 824,318 5,742 93,582 2,364 917,900 8,106 Total 15,341,394 204,117 1,842,251 18,570 17,183,645 222,687 Nonspecific allowance — — — — — 27,374 Total $ 15,341,394 $ 204,117 $ 1,842,251 $ 18,570 $ 17,183,645 $ 250,061 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 June 30, 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 $ 10,331,701 $ 144,217 $ 24,736 $ 922 $ 10,356,437 $ 145,139 Commercial real estate 3,581,966 46,745 — — 3,581,966 46,745 Residential mortgage 202,520 2,995 1,678,403 15,695 1,880,923 18,690 Personal 500,240 3,624 87,183 2,377 587,423 6,001 Total 14,616,427 197,581 1,790,322 18,994 16,406,749 216,575 Nonspecific allowance — — — — — 26,684 Total $ 14,616,427 $ 197,581 $ 1,790,322 $ 18,994 $ 16,406,749 $ 243,259
Schedule of Credit Quality Indicators [Table Text Block]	The following table summarizes the Company’s loan portfolio at June 30, 2017 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 $ 2,376,368 $ 120,473 $ 226,407 $ 123,992 $ — $ — $ 2,847,240 Services 2,921,510 12,452 17,111 7,754 — — 2,958,827 Wholesale/retail 1,507,063 16,224 9,788 10,620 — — 1,543,695 Manufacturing 513,442 6,540 16,499 9,656 — — 546,137 Healthcare 2,130,339 33,554 33,120 24,505 — — 2,221,518 Other commercial and industrial 453,712 2,961 17,861 20,526 25,374 104 520,538 Total commercial 9,902,434 192,204 320,786 197,053 25,374 104 10,637,955 Commercial real estate: Residential construction and land development 138,790 — 751 2,051 — — 141,592 Retail 720,730 1,774 — 301 — — 722,805 Office 859,722 2,855 — 396 — — 862,973 Multifamily 947,950 — 4,420 10 — — 952,380 Industrial 693,635 — — — — — 693,635 Other commercial real estate 314,187 — 3 1,017 — — 315,207 Total commercial real estate 3,675,014 4,629 5,174 3,775 — — 3,688,592 Residential mortgage: Permanent mortgage 212,563 1,693 478 1,273 750,891 22,142 989,040 Permanent mortgages guaranteed by U.S. government agencies — — — — 182,677 9,052 191,729 Home equity — — — — 746,661 11,768 758,429 Total residential mortgage 212,563 1,693 478 1,273 1,680,229 42,962 1,939,198 Personal 823,304 49 877 88 93,398 184 917,900 Total $ 14,613,315 $ 198,575 $ 327,315 $ 202,189 $ 1,799,001 $ 43,250 $ 17,183,645 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 June 30, 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 $ 2,031,955 $ 197,531 $ 421,025 $ 168,145 $ — $ — $ 2,818,656 Services 2,805,307 6,253 9,916 9,388 — — 2,830,864 Wholesale/retail 1,478,966 24,595 26,624 2,772 — — 1,532,957 Manufacturing 556,741 18,757 19,612 293 — — 595,403 Healthcare 2,011,934 29,420 8,917 875 — — 2,051,146 Other commercial and industrial 478,169 24,053 — 453 24,673 63 527,411 Total commercial 9,363,072 300,609 486,094 181,926 24,673 63 10,356,437 Commercial real estate: Residential construction and land development 152,343 — 972 4,261 — — 157,576 Retail 787,779 5,962 413 1,265 — — 795,419 Office 767,296 906 304 606 — — 769,112 Multifamily 781,058 — 6,077 65 — — 787,200 Industrial 645,510 — — 76 — — 645,586 Other commercial real estate 425,558 — 8 1,507 — — 427,073 Total commercial real estate 3,559,544 6,868 7,774 7,780 — — 3,581,966 Residential mortgage: Permanent mortgage 194,962 1,197 3,406 2,955 742,214 24,273 969,007 Permanent mortgages guaranteed by U.S. government agencies — — — — 172,991 19,741 192,732 Home equity — — — — 709,092 10,092 719,184 Total residential mortgage 194,962 1,197 3,406 2,955 1,624,297 54,106 1,880,923 Personal 496,534 — 3,590 116 86,945 238 587,423 Total $ 13,614,112 $ 308,674 $ 500,864 $ 192,777 $ 1,735,915 $ 54,407 $ 16,406,749
Summary of Impaired Loans [Table Text Block]	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 TDR and all loans repurchased from GNMA pools. A summary of impaired loans follows (in thousands): As of For the For the June 30, 2017 Three Months Ended Six Months Ended Recorded Investment June 30, 2017 June 30, 2017 Unpaid Principal Balance Total With No With Allowance Related Allowance Average Recorded Interest Income Recognized Average Recorded Interest Income Recognized Commercial: Energy $ 141,091 $ 123,992 $ 56,988 $ 67,004 $ 8,874 $ 117,209 $ — $ 128,246 $ — Services 11,209 7,754 7,754 — — 7,734 — 7,964 — Wholesale/retail 17,392 10,620 10,620 — — 10,855 — 11,013 — Manufacturing 10,223 9,656 9,656 — — 7,781 — 7,293 — Healthcare 24,795 24,505 18,883 5,622 802 12,707 — 12,665 — Other commercial and industrial 28,933 20,630 20,609 21 17 20,706 — 20,874 — Total commercial 233,643 197,157 124,510 72,647 9,693 176,992 — 188,055 — Commercial real estate: Residential construction and land development 3,676 2,051 2,051 — — 2,334 — 2,742 — Retail 518 301 301 — — 308 — 314 — Office 499 396 396 — — 404 — 411 — Multifamily 1,000 10 10 — — 17 — 24 — Industrial — — — — — 38 — 38 — Other commercial real estate 1,212 1,017 1,017 — — 1,024 — 1,119 — Total commercial real estate 6,905 3,775 3,775 — — 4,125 — 4,648 — Residential mortgage: Permanent mortgage 28,603 23,415 23,415 — — 23,801 307 23,135 598 Permanent mortgage guaranteed by U.S. government agencies 1 197,659 191,729 191,729 — — 202,946 2,021 205,159 3,925 Home equity 13,064 11,768 11,768 — — 11,776 — 11,643 — Total residential mortgage 239,326 226,912 226,912 — — 238,523 2,328 239,937 4,523 Personal 307 272 272 — — 253 — 281 — Total $ 480,181 $ 428,116 $ 355,469 $ 72,647 $ 9,693 $ 419,893 $ 2,328 $ 432,921 $ 4,523 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 June 30, 2017 , $9.1 million of these loans were nonaccruing and $183 million were 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, are recovered. A summary of impaired loans at December 31, 2016 follows (in thousands): Recorded Investment Unpaid Principal Balance Total With No Allowance With Allowance Related Allowance Commercial: Energy $ 146,897 $ 132,499 $ 121,418 $ 11,081 $ 762 Services 11,723 8,173 8,173 — — Wholesale/retail 17,669 11,407 11,407 — — Manufacturing 5,320 4,931 4,931 — — Healthcare 1,147 825 825 — — Other commercial and industrial 29,006 21,118 21,083 35 35 Total commercial 211,762 178,953 167,837 11,116 797 Commercial real estate: Residential construction and land development 4,951 3,433 3,433 — — Retail 530 326 326 — — Office 521 426 426 — — Multifamily 1,000 38 38 — — Industrial 76 76 76 — — Other commercial real estate 7,349 1,222 1,222 — — Total commercial real estate 14,427 5,521 5,521 — — Residential mortgage: Permanent mortgage 28,830 22,855 22,809 46 46 Permanent mortgage guaranteed by U.S. government agencies 1 205,564 199,387 199,387 — — Home equity 12,611 11,519 11,519 — — Total residential mortgage 247,005 233,761 233,715 46 46 Personal 332 290 290 — — Total $ 473,526 $ 418,525 $ 407,363 $ 11,162 $ 843 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 were nonaccruing and $188 million were accruing based on the guarantee by U.S. government agencies. A summary of impaired loans at June 30, 2016 follows (in thousands): For the For the As of June 30, 2016 Three Months Ended Six Months Ended Recorded Investment June 30, 2016 June 30, 2016 Unpaid Principal Balance Total With No Allowance With Allowance Related Allowance Average Recorded Investment Interest Income Recognized Average Recorded Investment Interest Income Recognized Commercial: Energy $ 202,369 $ 168,145 $ 136,264 $ 31,881 $ 4,228 $ 163,849 $ — $ 97,923 $ — Services 12,780 9,388 9,388 — — 9,450 — 9,839 — Wholesale/retail 8,697 2,772 2,772 — — 3,229 — 2,846 — Manufacturing 650 293 293 — — 303 — 312 — Healthcare 1,175 875 875 — — 949 — 973 — Other commercial and industrial 8,186 516 516 — — 542 — 569 — Total commercial 233,857 181,989 150,108 31,881 4,228 178,322 — 112,462 — Commercial real estate: Residential construction and land development 7,177 4,261 4,261 — — 4,525 — 4,335 — Retail 1,914 1,265 1,265 — — 1,283 — 1,292 — Office 907 606 606 — — 618 — 628 — Multifamily 1,000 65 65 — — 157 — 169 — Industrial 76 76 76 — — 76 — 76 — Other commercial real estate 7,445 1,507 1,355 152 18 1,865 — 1,890 — Total commercial real estate 18,519 7,780 7,628 152 18 8,524 — 8,390 — Residential mortgage: Permanent mortgage 33,793 27,228 27,117 111 64 27,362 304 28,106 631 Permanent mortgage guaranteed by U.S. government agencies 1 198,534 192,732 192,732 — — 191,430 2,023 195,563 3,795 Home equity 10,964 10,092 10,092 — — 10,311 — 10,224 — Total residential mortgage 243,291 230,052 229,941 111 64 229,103 2,327 233,893 4,426 Personal 1,174 354 354 — — 342 — 409 — Total $ 496,841 $ 420,175 $ 388,031 $ 32,144 $ 4,310 $ 416,291 $ 2,327 $ 355,154 $ 4,426 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 June 30, 2016 , $20 million of these loans were nonaccruing and $173 million were accruing based on the guarantee by U.S. government agencies.
Troubled Debt Restructurings [Table Text Block]	Troubled Debt Restructurings A summary of troubled debt restructurings ("TDRs") by accruing status as of June 30, 2017 is as follows (in thousands): As of June 30, 2017 Amounts Charged Off During: Recorded Investment Performing in Accordance With Modified Terms Not Performing in Accordance With Modified Terms Specific Allowance Three Months Ended June 30, 2017 Six Months Ended Nonaccruing TDRs: Commercial: Energy $ 22,466 $ 12,692 $ 9,774 $ 4,308 $ — $ — Services 7,208 6,561 647 — 3 3 Wholesale/retail 10,524 10,524 — — — — Manufacturing 195 195 — — — — Healthcare — — — — — — Other commercial and industrial 20,531 35 20,496 — — — Total commercial 60,924 30,007 30,917 4,308 3 3 Commercial real estate: Residential construction and land development 381 145 236 — — — Retail 301 301 — — — — Office 121 — 121 — — — Multifamily — — — — — — Industrial — — — — — — Other commercial real estate 365 365 — — — — Total commercial real estate 1,168 811 357 — — — Residential mortgage: Permanent mortgage 14,284 9,939 4,345 — — — Permanent mortgage guaranteed by U.S. government agencies 5,962 1,176 4,786 — — — Home equity 5,549 4,239 1,310 — — 31 Total residential mortgage 25,795 15,354 10,441 — — 31 Personal 228 228 — — 7 8 Total nonaccruing TDRs $ 88,115 $ 46,400 $ 41,715 $ 4,308 $ 10 $ 42 Accruing TDRs: Permanent mortgages guaranteed by U.S. government agencies 80,624 24,506 56,118 — — — Total TDRs $ 168,739 $ 70,906 $ 97,833 $ 4,308 $ 10 $ 42 A summary of troubled debt restructurings 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 Nonaccruing TDRs: Commercial: Energy $ 16,893 $ 10,867 $ 6,026 $ — 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 — 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 Permanent mortgage guaranteed by U.S. government agencies 6,702 2,241 4,461 — Home equity 5,346 4,458 888 — Total residential mortgage 26,924 16,874 10,050 46 Personal 237 236 1 — Total nonaccuring TDRs $ 65,747 $ 47,449 $ 18,298 $ 46 Accruing TDRs: Permanent mortgages guaranteed by U.S. government agencies 81,370 27,289 54,081 — Total TDRs $ 147,117 $ 74,738 $ 72,379 $ 46 A summary of troubled debt restructurings by accruing status as of June 30, 2016 is as follows (in thousands): As of June 30, 2016 Amounts Charged Off During: Recorded Investment Performing in Accordance With Modified Terms Not Performing in Accordance With Modified Terms Specific Allowance Three Months Ended Six Months Ended Nonaccruing TDRs: Commercial: Energy $ 2,246 $ — $ 2,246 $ — $ 500 $ 500 Services 8,610 7,853 757 — — — Wholesale/retail 2,467 2,427 40 — — — Manufacturing 253 253 — — — — Healthcare 640 640 — — — — Other commercial and industrial 516 63 453 — — 57 Total commercial 14,732 11,236 3,496 — 500 557 Commercial real estate: Residential construction and land development 1,601 1,079 522 — — — Retail 1,264 907 357 — — — Office 152 152 — — — — Multifamily — — — — — — Industrial — — — — — — Other commercial real estate 793 372 421 — — — Total commercial real estate 3,810 2,510 1,300 — — — Residential mortgage: Permanent mortgage 17,367 12,462 4,905 64 37 52 Permanent mortgage guaranteed by U.S. government agencies 9,709 2,024 7,685 — — — Home equity 4,763 4,139 624 — 60 126 Total residential mortgage 31,839 18,625 13,214 64 97 178 Personal 298 276 22 — 3 9 Total nonaccruing TDRs $ 50,679 $ 32,647 $ 18,032 $ 64 $ 600 $ 744 Accruing TDRs: Permanent mortgages guaranteed by U.S. government agencies 78,806 27,999 50,807 — — — Total TDRs $ 129,485 $ 60,646 $ 68,839 $ 64 $ 600 $ 744 Troubled debt restructurings generally consist of interest rate concessions, payment stream concessions or a combination of concessions to distressed borrowers. The following tables detail the recorded balance of loans at June 30, 2017 by class that were restructured during the three months ended June 30, 2017 by primary type of concession (in thousands): Three Months Ended Accruing Nonaccrual Total Payment Stream Combination & Other Total Payment Stream Combination & Other Total Commercial: Energy $ — $ — $ — $ — $ — $ — $ — Services — — — — — — — Wholesale/retail — — — — 626 626 626 Manufacturing — — — — — — — Healthcare — — — — — — — Other commercial and industrial — — — 20,242 — 20,242 20,242 Total commercial — — — 20,242 626 20,868 20,868 Commercial real estate: Residential construction and land development — — — — — — — Retail — — — — — — — Office — — — — — — — Multifamily — — — — — — — Industrial — — — — — — — Other commercial real estate — — — — — — — Total commercial real estate — — — — — — — Residential mortgage: Permanent mortgage — — — 138 53 191 191 Permanent mortgage guaranteed by U.S. government agencies 10,410 1,568 11,978 223 — 223 12,201 Home equity — — — 26 559 585 585 Total residential mortgage 10,410 1,568 11,978 387 612 999 12,977 Personal — — — — 47 47 47 Total $ 10,410 $ 1,568 $ 11,978 $ 20,629 $ 1,285 $ 21,914 $ 33,892 Six Months Ended Accruing Nonaccrual Total Payment Stream Combination & Other Total Payment Stream Combination & Other Total Commercial: Energy $ — $ — $ — $ 13,010 $ — $ 13,010 $ 13,010 Services — — — — — — — Wholesale/retail — — — — 626 626 626 Manufacturing — — — — — — — Healthcare — — — — — — — Other commercial and industrial — — — 20,242 — 20,242 20,242 Total commercial — — — 33,252 626 33,878 33,878 Commercial real estate: Residential construction and land development — — — — — — — Retail — — — — — — — Office — — — — — — — Multifamily — — — — — — — Industrial — — — — — — — Other commercial real estate — — — — — — — Total commercial real estate — — — — — — — Residential mortgage: Permanent mortgage — — — 153 84 237 237 Permanent mortgage guaranteed by U.S. government agencies 14,883 2,586 17,469 224 85 309 17,778 Home equity — — — 149 1,053 1,202 1,202 Total residential mortgage 14,883 2,586 17,469 526 1,222 1,748 19,217 Personal — — — — 51 51 51 Total $ 14,883 $ 2,586 $ 17,469 $ 33,778 $ 1,899 $ 35,677 $ 53,146 Troubled debt restructurings generally consist of interest rate concessions, payment stream concessions or a combination of concessions to distressed borrowers. The following tables detail the recorded balance of loans by class that were restructured during three months ended June 30, 2016 by primary type of concession (in thousands): Three Months Ended Accruing Nonaccrual Total Payment Stream Combination & Other Total Payment Stream Combination & Other Total Commercial: Energy $ — $ — $ — $ — $ — $ — $ — Services — — — — — — — Wholesale/retail — — — — — — — Manufacturing — — — — — — — Healthcare — — — — — — — Other commercial and industrial — — — — — — — Total commercial — — — — — — — Commercial real estate: Residential construction and land development — — — — — — — Retail — — — — — — — Office — — — — — — — Multifamily — — — — — — — Industrial — — — — — — — Other commercial real estate — — — — — — — Total commercial real estate — — — — — — — Residential mortgage: Permanent mortgage — — — 684 1,183 1,867 1,867 Permanent mortgage guaranteed by U.S. government agencies 2,783 4,455 7,238 — 625 625 7,863 Home equity — — — 48 329 377 377 Total residential mortgage 2,783 4,455 7,238 732 2,137 2,869 10,107 Personal — — — — 65 65 65 Total $ 2,783 $ 4,455 $ 7,238 $ 732 $ 2,202 $ 2,934 $ 10,172 Six Months Ended Accruing Nonaccrual Total Payment Stream Combination & Other Total Payment Stream Combination & Other Total Commercial: Energy $ — $ — $ — $ 501 $ — $ 501 $ 501 Services — — — — — — — Wholesale/retail — — — — — — — Manufacturing — — — — — — — Healthcare — — — — — — — Other commercial and industrial — — — — — — — Total commercial — — — 501 — 501 501 Commercial real estate: Residential construction and land development — — — — — — — Retail — — — — — — — Office — — — — — — — Multifamily — — — — — — — Industrial — — — — — — — Other commercial real estate — — — — — — — Total commercial real estate — — — — — — — Residential mortgage: Permanent mortgage — — — 1,046 1,244 2,290 2,290 Permanent mortgage guaranteed by U.S. government agencies 6,625 7,818 14,443 — 625 625 15,068 Home equity — — — 48 791 839 839 Total residential mortgage 6,625 7,818 14,443 1,094 2,660 3,754 18,197 Personal — — — — 72 72 72 Total $ 6,625 $ 7,818 $ 14,443 $ 1,595 $ 2,732 $ 4,327 $ 18,770 The following table summarizes, by loan class, the recorded investment at June 30, 2017 and 2016 , respectively, of loans modified as TDRs within the previous 12 months and for which there was a payment default during the three months ended June 30, 2017 and 2016 , respectively (in thousands): Three Months Ended Six Months Ended Accruing Nonaccrual Total Accruing Nonaccrual Total Commercial: Energy $ — $ 9,774 $ 9,774 $ — $ 9,774 $ 9,774 Services — — — — — — Wholesale/retail — — — — — — Manufacturing — — — — — — Healthcare — — — — — — Other commercial and industrial — 20,242 20,242 — 20,242 20,242 Total commercial — 30,016 30,016 — 30,016 30,016 Commercial real estate: Residential construction and land development — — — — — — Retail — — — — — — Office — — — — — — Multifamily — — — — — — Industrial — — — — — — Other commercial real estate — — — — — — Total commercial real estate — — — — — — Residential mortgage: Permanent mortgage — 161 161 — 161 161 Permanent mortgage guaranteed by U.S. government agencies 22,234 918 23,152 22,590 918 23,508 Home equity — 1,113 1,113 — 1,262 1,262 Total residential mortgage 22,234 2,192 24,426 22,590 2,341 24,931 Personal — — — — — — Total $ 22,234 $ 32,208 $ 54,442 $ 22,590 $ 32,357 $ 54,947 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]	Nonaccrual & Past Due Loans Past due status for all loan classes is based on the actual number of days since the last payment was due according to the contractual terms of the loans. A summary of loans currently performing, loans past due and accruing and nonaccrual loans as of June 30, 2017 is as follows (in thousands): Past Due Current 30 to 59 Days 60 to 89 Days 90 Days or More Nonaccrual Total Commercial: Energy $ 2,723,248 $ — $ — $ — $ 123,992 $ 2,847,240 Services 2,949,562 50 180 1,281 7,754 2,958,827 Wholesale/retail 1,532,986 89 — — 10,620 1,543,695 Manufacturing 536,481 — — — 9,656 546,137 Healthcare 2,196,088 925 — — 24,505 2,221,518 Other commercial and industrial 499,743 45 119 1 20,630 520,538 Total commercial 10,438,108 1,109 299 1,282 197,157 10,637,955 Commercial real estate: Residential construction and land development 139,070 471 — — 2,051 141,592 Retail 722,504 — — — 301 722,805 Office 862,577 — — — 396 862,973 Multifamily 952,370 — — — 10 952,380 Industrial 693,635 — — — — 693,635 Other commercial real estate 314,187 3 — — 1,017 315,207 Total commercial real estate 3,684,343 474 — — 3,775 3,688,592 Residential mortgage: Permanent mortgage 962,443 2,024 1,026 132 23,415 989,040 Permanent mortgages guaranteed by U.S. government agencies 36,867 18,416 13,581 113,813 9,052 191,729 Home equity 744,735 1,564 362 — 11,768 758,429 Total residential mortgage 1,744,045 22,004 14,969 113,945 44,235 1,939,198 Personal 916,852 487 289 — 272 917,900 Total $ 16,783,348 $ 24,074 $ 15,557 $ 115,227 $ 245,439 $ 17,183,645 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 June 30, 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 $ 2,647,678 $ — — $ 2,833 $ 168,145 $ 2,818,656 Services 2,817,217 494 3,765 — 9,388 2,830,864 Wholesale/retail 1,530,110 75 — — 2,772 1,532,957 Manufacturing 595,110 — — — 293 595,403 Healthcare 2,050,271 — — — 875 2,051,146 Other commercial and industrial 526,691 76 82 46 516 527,411 Total commercial 10,167,077 645 3,847 2,879 181,989 10,356,437 Commercial real estate: Residential construction and land development 153,315 — — — 4,261 157,576 Retail 794,154 — — — 1,265 795,419 Office 768,506 — — — 606 769,112 Multifamily 784,826 2,309 — — 65 787,200 Industrial 645,510 — — — 76 645,586 Other commercial real estate 425,566 — — — 1,507 427,073 Total commercial real estate 3,571,877 2,309 — — 7,780 3,581,966 Residential mortgage: Permanent mortgage 935,857 5,798 124 — 27,228 969,007 Permanent mortgages guaranteed by U.S. government agencies 42,019 15,349 11,869 103,754 19,741 192,732 Home equity 707,024 1,889 159 20 10,092 719,184 Total residential mortgage 1,684,900 23,036 12,152 103,774 57,061 1,880,923 Personal 586,611 400 58 — 354 587,423 Total $ 16,010,465 $ 26,390 16,057 $ 106,653 $ 247,184 $ 16,406,749

Mortgage Banking Activities (Ta

Mortgage Banking Activities (Tables)	6 Months Ended
	Jun. 30, 2017
Mortgage Banking [Abstract]
Components of Residential Mortgage Loans Held For Sale [Table Text Block]	June 30, 2017 Dec. 31, 2016 June 30, 2016 Unpaid Principal Balance/ Notional Fair Value Unpaid Principal Balance/ Notional Fair Value Unpaid Principal Balance/ Notional Fair Value Residential mortgage loans held for sale $ 269,772 $ 275,179 $ 286,414 $ 286,971 $ 404,507 $ 417,542 Residential mortgage loan commitments 362,088 10,993 318,359 9,733 965,631 25,499 Forward sales contracts 587,595 1,087 569,543 5,193 1,216,966 (12,313 ) $ 287,259 $ 301,897 $ 430,728
Mortgage Banking Revenue [Table Text Block]	Mortgage banking revenue was as follows (in thousands): Three Months Ended Six Months Ended 2017 2016 2017 2016 Production revenue: Net realized gains on sale of mortgage loans $ 11,787 $ 15,865 $ 20,402 $ 24,314 Net change in unrealized gain on mortgage loans held for sale 985 3,884 4,827 7,167 Net change in the fair value of mortgage loan commitments (3,274 ) 5,329 1,260 17,365 Net change in the fair value of forward sales contracts 4,342 (5,992 ) (4,106 ) (13,113 ) Total production revenue 13,840 19,086 22,383 35,733 Servicing revenue 16,436 15,798 33,084 31,251 Total mortgage banking revenue $ 30,276 $ 34,884 $ 55,467 $ 66,984
Summary of Mortgage Servicing Rights [Table Text Block]	The following represents a summary of mortgage servicing rights (Dollars in thousands): June 30, Dec. 31, June 30, Number of residential mortgage loans serviced for others 138,335 139,340 137,210 Outstanding principal balance of residential mortgage loans serviced for others $ 22,095,232 $ 21,997,568 $ 21,178,387 Weighted average interest rate 3.95 % 3.97 % 4.06 % Remaining term (in months) 299 301 301
Activity in Capitalized Mortgage Servicing Rights [Table Text Block]	Activity in capitalized mortgage servicing rights during the three months ended June 30, 2017 was as follows (in thousands): Purchased Originated Total Balance, March 31, 2017 $ 8,316 $ 241,087 $ 249,403 Additions, net — 11,078 11,078 Change in fair value due to scheduled payments and full-balance payoffs (464 ) (7,835 ) (8,299 ) Change in fair value due to market assumption changes 143 (7,086 ) (6,943 ) Balance, June 30, 2017 $ 7,995 $ 237,244 $ 245,239 Purchased Originated Total Balance, Dec. 31, 2016 $ 8,909 $ 238,164 $ 247,073 Additions, net — 19,514 19,514 Change in fair value due to scheduled payments and full-balance payoffs (973 ) (15,288 ) (16,261 ) Change in fair value due to market assumption changes 59 (5,146 ) (5,087 ) Balance, June 30, 2017 $ 7,995 $ 237,244 $ 245,239 Activity in capitalized mortgage servicing rights during the three months ended June 30, 2016 was as follows (in thousands): Purchased Originated Total Balance, March 31, 2016 $ 5,949 $ 190,106 $ 196,055 Additions, net — 20,773 20,773 Change in fair value due to scheduled payments and full-balance payoffs (730 ) (9,068 ) (9,798 ) Change in fair value due to market assumption changes (1,152 ) (15,131 ) (16,283 ) Balance, June 30, 2016 $ 4,067 $ 186,680 $ 190,747 Purchased Originated Total Balance, Dec. 31, 2015 $ 9,911 $ 208,694 $ 218,605 Additions, net — 34,355 34,355 Change in fair value due to scheduled payments and full-balance payoffs (1,356 ) (16,586 ) (17,942 ) Change in fair value due to market assumption changes (4,488 ) (39,783 ) (44,271 ) Balance, June 30, 2016 $ 4,067 $ 186,680 $ 190,747
Assumptions to Value Mortgage Servicing Rights [Table Text Block]	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 based on significant unobservable inputs were as follows: June 30, Dec. 31, June 30, Discount rate – risk-free rate plus a market premium 9.84% 10.08% 10.09% Prepayment rate - based upon loan interest rate, original term and loan type 8.61%-15.91% 8.98%-16.91% 9.26%-42.77% Loan servicing costs – annually per loan based upon loan type: Performing loans $65-$120 $63 - $120 $63 - $120 Delinquent loans $150-$500 $150 - $500 $150 - $500 Loans in foreclosure $1,000-$4,250 $650 - $4,250 $650 - $4,250 Escrow earnings rate – indexed to rates paid on deposit accounts with comparable average life 1.95% 1.98% 0.99% Primary/secondary mortgage rate spread 105 bps 105 bps 115 bps
Aging Status of Mortgage Loans Serviced For Others [Table Text Block]	The aging status of our mortgage loans serviced for others by investor at June 30, 2017 follows (in thousands): Past Due Current 30 to 59 Days 60 to 89 Days 90 Days or More Total FHLMC $ 8,083,330 $ 48,659 $ 12,294 $ 27,338 $ 8,171,621 FNMA 6,756,211 46,918 10,679 23,981 6,837,789 GNMA 6,331,439 170,889 47,335 16,082 6,565,745 Other 514,272 3,278 932 1,595 520,077 Total $ 21,685,252 $ 269,744 $ 71,240 $ 68,996 $ 22,095,232
Summary of Unresolved Deficiency Requests and Related Accrual for Credit Losses [Table Text Block]	A summary of unresolved deficiency requests from the agencies follows (in thousands, except for number of unresolved deficiency requests): June 30, 2017 2016 Number of unresolved deficiency requests 206 211 Aggregate outstanding principal balance subject to unresolved deficiency requests $ 13,370 $ 15,920 Unpaid principal balance subject to indemnification by the Company 5,074 5,519
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). Three Months Ended Six Months Ended 2017 2016 2017 2016 Beginning balance $ 2,587 $ 2,974 $ 2,788 $ 3,359 Provision for losses (895 ) 368 (1,094 ) 250 Charge-offs, net (45 ) (89 ) (47 ) (356 ) Ending balance $ 1,647 $ 3,253 $ 1,647 $ 3,253

Commitments and Contingent Li26

Commitments and Contingent Liabilities Commitments and Contingent Liabilities - Variable Interest Entities (Tables)	6 Months Ended
	Jun. 30, 2017
Commitments and Contingencies Disclosure [Abstract]
Schedule of Variable Interest Entities [Table Text Block]	A summary of consolidated and unconsolidated alternative investments as of June 30, 2017 , December 31, 2016 and June 30, 2016 is as follows (in thousands): June 30, 2017 Loans Other assets Other liabilities Other borrowings Non-controlling interests Consolidated: Private equity funds $ — $ 16,905 $ — $ — $ 14,199 Tax credit entities 10,000 11,274 — 10,964 10,000 Other — 15,894 1,621 878 2,877 Total consolidated $ 10,000 $ 44,073 $ 1,621 $ 11,842 $ 27,076 Unconsolidated: Tax credit entities $ 59,744 $ 148,525 $ 63,822 $ — $ — Other — 33,155 13,680 — — Total unconsolidated $ 59,744 $ 181,680 $ 77,502 $ — $ — Dec. 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 $ — $ — June 30, 2016 Loans Other assets Other liabilities Other borrowings Non-controlling interests Consolidated: Private equity funds $ — $ 20,469 $ — $ — $ 16,316 Tax credit entities 10,000 11,895 — 10,964 10,000 Other — 35,387 2,004 2,272 7,589 Total consolidated $ 10,000 $ 67,751 $ 2,004 $ 13,236 $ 33,905 Unconsolidated: Tax credit entities $ 32,679 $ 102,138 $ 30,953 $ — $ — Other — 23,439 13,767 — — Total unconsolidated $ 32,679 $ 125,577 $ 44,720 $ — $ —

Shareholders' Equity (Tables)

Shareholders' Equity (Tables)	6 Months Ended
	Jun. 30, 2017
Stockholders' Equity Note [Abstract]
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 Total Balance, Dec. 31, 2015 $ 23,284 $ 68 $ (1,765 ) $ 21,587 Net change in unrealized gain (loss) 166,566 — — 166,566 Reclassification adjustments included in earnings: Interest revenue, Investment securities, Taxable securities — (112 ) — (112 ) Gain on available for sale securities, net (9,290 ) — — (9,290 ) Other comprehensive income (loss), before income taxes 157,276 (112 ) — 157,164 Federal and state income taxes 1 61,163 (44 ) — 61,119 Other comprehensive income (loss), net of income taxes 96,113 (68 ) — 96,045 Balance, June 30, 2016 $ 119,397 $ — $ (1,765 ) $ 117,632 Balance, Dec. 31, 2016 $ (9,087 ) $ — $ (1,880 ) $ (10,967 ) Net change in unrealized gain (loss) 33,369 — — 33,369 Reclassification adjustments included in earnings: Gain on available for sale securities, net (2,429 ) — — (2,429 ) Other comprehensive income, before income taxes 30,940 — — 30,940 Federal and state income taxes 1 12,009 — 12,009 Other comprehensive income, net of income taxes 18,931 — — 18,931 Balance, June 30, 2017 $ 9,844 $ — $ (1,880 ) $ 7,964 1 Calculated using a 39 percent effective tax rate.

Earnings Per Share (Tables)

Earnings Per Share (Tables)	6 Months Ended
	Jun. 30, 2017
Earnings Per Share [Abstract]
Earnings Per Share [Table Text Block]	(In thousands, except share and per share amounts) Three Months Ended Six Months Ended 2017 2016 2017 2016 Numerator: Net income attributable to BOK Financial Corp. shareholders $ 88,147 $ 65,801 $ 176,503 $ 108,365 Less: Earnings allocated to participating securities 926 821 1,929 1,359 Numerator for basic earnings per share – income available to common shareholders 87,221 64,980 174,574 107,006 Effect of reallocating undistributed earnings of participating securities 1 — 1 — Numerator for diluted earnings per share – income available to common shareholders $ 87,222 $ 64,980 $ 174,575 $ 107,006 Denominator: Weighted average shares outstanding 65,416,274 66,069,392 65,436,909 66,100,279 Less: Participating securities included in weighted average shares outstanding 686,522 823,505 714,165 829,065 Denominator for basic earnings per common share 64,729,752 65,245,887 64,722,744 65,271,214 Dilutive effect of employee stock compensation plans 1 63,382 57,039 65,578 45,963 Denominator for diluted earnings per common share 64,793,134 65,302,926 64,788,322 65,317,177 Basic earnings per share $ 1.35 $ 1.00 $ 2.70 $ 1.64 Diluted earnings per share $ 1.35 $ 1.00 $ 2.69 $ 1.64 1 Excludes employee stock options with exercise prices greater than current market price. — — — 145,247

Reportable Segments (Tables)

Reportable Segments (Tables)	6 Months Ended
	Jun. 30, 2017
Segment Reporting [Abstract]
Reportable Segments [Table Text Block]	Reportable segments reconciliation to the Consolidated Financial Statements for the three months ended June 30, 2017 is as follows (in thousands): Commercial Consumer Wealth Management Funds Management and Other BOK Financial Consolidated Net interest revenue from external sources $ 144,164 $ 23,503 $ 10,474 $ 27,063 $ 205,204 Net interest revenue (expense) from internal sources (20,347 ) 11,837 10,325 (1,815 ) — Net interest revenue 123,817 35,340 20,799 25,248 205,204 Provision for credit losses 1,228 926 (93 ) (2,061 ) — Net interest revenue after provision for credit losses 122,589 34,414 20,892 27,309 205,204 Other operating revenue 55,778 52,102 75,569 (1,197 ) 182,252 Other operating expense 59,128 55,709 60,615 75,433 250,885 Net direct contribution 119,239 30,807 35,846 (49,321 ) 136,571 Gain on financial instruments, net 3 5,224 — (5,227 ) — Change in fair value of mortgage servicing rights — (6,943 ) — 6,943 — Gain on repossessed assets, net 1,403 98 — (1,501 ) — Corporate expense allocations 8,862 17,039 9,947 (35,848 ) — Net income before taxes 111,783 12,147 25,899 (13,258 ) 136,571 Federal and state income taxes 43,484 4,725 10,075 (10,579 ) 47,705 Net income 68,299 7,422 15,824 (2,679 ) 88,866 Net income attributable to non-controlling interests — — — 719 719 Net income attributable to BOK Financial Corp. shareholders $ 68,299 $ 7,422 $ 15,824 $ (3,398 ) $ 88,147 Average assets $ 17,596,273 $ 8,845,398 $ 6,763,093 $ (836,193 ) $ 32,368,571 Reportable segments reconciliation to the Consolidated Financial Statements for the six months ended June 30, 2017 is as follows (in thousands): Commercial Consumer Wealth Management Funds Management and Other BOK Financial Consolidated Net interest revenue from external sources $ 278,868 $ 44,632 $ 21,960 $ 60,926 $ 406,386 Net interest revenue (expense) from internal sources (37,140 ) 22,789 19,181 (4,830 ) — Net interest revenue 241,728 67,421 41,141 56,096 406,386 Provision for credit losses (234 ) 2,198 (53 ) (1,911 ) — Net interest revenue after provision for credit losses 241,962 65,223 41,194 58,007 406,386 Other operating revenue 102,048 99,408 149,727 1,365 352,548 Other operating expense 111,565 109,242 121,025 153,764 495,596 Net direct contribution 232,445 55,389 69,896 (94,392 ) 263,338 Gain on financial instruments, net 41 3,557 — (3,598 ) — Change in fair value of mortgage servicing rights — (5,087 ) — 5,087 — Gain (loss) on repossessed assets, net 1,398 (39 ) — (1,359 ) — Corporate expense allocations 17,493 33,908 20,619 (72,020 ) — Net income before taxes 216,391 19,912 49,277 (22,242 ) 263,338 Federal and state income taxes 84,176 7,746 19,169 (25,283 ) 85,808 Net income 132,215 12,166 30,108 3,041 177,530 Net income attributable to non-controlling interests — — — 1,027 1,027 Net income attributable to BOK Financial Corp. shareholders $ 132,215 $ 12,166 $ 30,108 $ 2,014 $ 176,503 Average assets $ 17,517,960 $ 8,747,524 $ 6,960,872 $ (566,196 ) $ 32,660,160 Reportable segments reconciliation to the Consolidated Financial Statements for the three months ended June 30, 2016 is as follows (in thousands): Commercial Consumer Wealth Management Funds Management and Other BOK Financial Consolidated Net interest revenue from external sources $ 118,480 $ 22,349 $ 6,271 $ 35,512 $ 182,612 Net interest revenue (expense) from internal sources (14,575 ) 8,876 $ 7,193 (1,494 ) — Net interest revenue 103,905 31,225 13,464 34,018 182,612 Provision for credit losses 6,852 1,318 (239 ) 12,069 20,000 Net interest revenue after provision for credit losses 97,053 29,907 13,703 21,949 162,612 Other operating revenue 51,497 57,440 75,772 833 185,542 Other operating expense 52,594 62,806 61,414 74,571 251,385 Net direct contribution 95,956 24,541 28,061 (51,789 ) 96,769 Gain on financial instruments, net — 15,045 — (15,045 ) — Change in fair value of mortgage servicing rights — (16,283 ) — 16,283 — Gain (loss) on repossessed assets, net (598 ) 252 — 346 — Corporate expense allocations 8,883 16,630 10,417 (35,930 ) — Net income before taxes 86,475 6,925 17,644 (14,275 ) 96,769 Federal and state income taxes 33,639 2,694 6,864 (12,700 ) 30,497 Net income 52,836 4,231 10,780 (1,575 ) 66,272 Net gain attributable to non-controlling interests — — — 471 471 Net income attributable to BOK Financial Corp. shareholders $ 52,836 $ 4,231 $ 10,780 $ (2,046 ) $ 65,801 Average assets $ 16,973,663 $ 8,774,881 $ 5,765,390 $ 472,108 $ 31,986,042 Reportable segments reconciliation to the Consolidated Financial Statements for the six months ended June 30, 2016 is as follows (in thousands): Commercial Consumer Wealth Management Funds Management and Other BOK Financial Consolidated Net interest revenue from external sources $ 235,116 $ 43,799 $ 12,349 $ 73,920 $ 365,184 Net interest revenue (expense) from internal sources (29,208 ) 18,229 $ 14,857 (3,878 ) — Net interest revenue 205,908 62,028 27,206 70,042 365,184 Provision for credit losses 28,423 3,020 (390 ) 23,947 55,000 Net interest revenue after provision for credit losses 177,485 59,008 27,596 46,095 310,184 Other operating revenue 96,605 111,469 144,518 (9,636 ) 342,956 Other operating expense 108,663 118,524 122,098 144,670 493,955 Net direct contribution 165,427 51,953 50,016 (108,211 ) 159,185 Gain on financial instruments, net — 31,626 — (31,626 ) — Change in fair value of mortgage servicing rights — (44,271 ) — 44,271 — Gain (loss) on repossessed assets, net (680 ) 406 — 274 — Corporate expense allocations 17,627 32,608 20,952 (71,187 ) — Net income before taxes 147,120 7,106 29,064 (24,105 ) 159,185 Federal and state income taxes 57,230 2,764 11,306 (19,375 ) 51,925 Net income 89,890 4,342 17,758 (4,730 ) 107,260 Net loss attributable to non-controlling interests — — — (1,105 ) (1,105 ) Net income attributable to BOK Financial Corp. shareholders $ 89,890 $ 4,342 $ 17,758 $ (3,625 ) $ 108,365 Average assets $ 16,971,339 $ 8,731,085 $ 5,665,218 $ 379,615 $ 31,747,257

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	6 Months Ended
	Jun. 30, 2017
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 measured on a recurring basis was as follows as of June 30, 2017 (in thousands): Total Quoted Prices in Active Markets for Identical Instruments (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Assets: Trading securities: U.S. government agency debentures $ 20,954 $ — $ 20,954 $ — U.S. government agency residential mortgage-backed securities 365,171 — 365,171 — Municipal and other tax-exempt securities 45,444 — 45,444 — Other trading securities 9,845 — 9,845 — Total trading securities 441,414 — 441,414 — Available for sale securities: U.S. Treasury 998 998 — — Municipal and other tax-exempt securities 32,765 — 28,110 4,655 U.S. government agency residential mortgage-backed securities 5,382,377 — 5,382,377 — Privately issued residential mortgage-backed securities 103,383 — 103,383 — Commercial mortgage-backed securities guaranteed by U.S. government agencies 2,782,070 — 2,782,070 — Other debt securities 4,152 — — 4,152 Perpetual preferred stock 16,568 — 16,568 — Equity securities and mutual funds 18,728 3,516 15,212 — Total available for sale securities 8,341,041 4,514 8,327,720 8,807 Fair value option securities – U.S. government agency residential mortgage-backed securities 445,169 — 445,169 — Residential mortgage loans held for sale 287,259 — 274,524 12,735 Mortgage servicing rights 1 245,239 — — 245,239 Derivative contracts, net of cash collateral 2 280,289 20,213 260,076 — Liabilities: Derivative contracts, net of cash collateral 2 285,819 5,919 279,900 — 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 6 , Mortgage Banking Activities. 2 See Note 3 for detail of fair value of derivative contracts by contract type. Derivative contracts in asset positions that were valued based on quoted prices in active markets for identical instruments (Level 1) are primarily exchange-traded energy and interest rate derivative contacts. Derivative contacts in liability positions that were valued using quoted prices in active markets for identical instruments are exchange-traded interest rate and agricultural derivative contracts, net of cash margin. The fair value of financial assets and liabilities measured on a recurring basis was as follows as of December 31, 2016 (in thousands): Total Quoted Prices in Active Markets for Identical Instruments (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs Assets: Trading securities: U.S. government agency debentures $ 6,234 $ — $ 6,234 $ — U.S. government 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 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 1 247,073 — — 247,073 Derivative contracts, net of cash collateral 2 689,872 7,541 682,331 — Liabilities: Derivative contracts, net of cash collateral 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 6 , Mortgage Banking Activities. 2 See Note 3 for detail of fair value of derivative contracts by contract type. Derivative contracts based on quoted prices in active markets for identical instruments (Level 1) are exchange-traded interest-rate and energy derivative contacts, net of cash margin. Derivative contracts in liability positions 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 measured on a recurring basis was as follows as of June 30, 2016 (in thousands): Total Quoted Prices in Active Markets for Identical Instruments (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs Assets: Trading securities: U.S. government agency debentures $ 18,909 $ — $ 18,909 $ — U.S. government agency residential mortgage-backed securities 122,306 — 122,306 — Municipal and other tax-exempt securities 52,721 — 52,721 — Other trading securities 17,686 — 17,686 — Total trading securities 211,622 — 211,622 — Available for sale securities: U.S. Treasury 1,004 1,004 — — Municipal and other tax-exempt securities 50,262 — 40,662 9,600 U.S. government agency residential mortgage-backed securities 5,700,268 — 5,700,268 — Privately issued residential mortgage-backed securities 126,313 — 126,313 — Commercial mortgage-backed securities guaranteed by U.S. government agencies 2,911,946 — 2,911,946 — Other debt securities 4,151 — — 4,151 Perpetual preferred stock 17,931 — 17,931 — Equity securities and mutual funds 18,814 3,785 15,029 — Total available for sale securities 8,830,689 4,789 8,812,149 13,751 Fair value option securities: U.S. Treasury 25,306 25,306 — — U.S. government agency residential mortgage-backed securities 237,959 — 237,959 — Total fair value option securities 263,265 25,306 237,959 — Residential mortgage loans held for sale 430,728 — 420,979 9,749 Mortgage servicing rights 1 190,747 — — 190,747 Derivative contracts, net of cash collateral 2 883,673 7,246 876,427 — Liabilities: Derivative contracts, net of cash collateral 2 719,159 4,808 714,351 — 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 6 , Mortgage Banking Activities. 2 See Note 3 for detail of fair value of derivative contracts by contract type. Derivative contracts based on quoted prices in active markets for identical instruments (Level 1) are exchange-traded energy and agricultural derivative contacts, net of cash margin. Derivative contracts in liability positions that were valued using quoted prices in active markets for identical instruments (Level 1) are exchange-traded interest rate and energy derivative contracts, net cash margin.
Fair Value Assets Measured On Recurring Basis, Significant Unobservable Inputs [Table Text Block]	The following represents the changes for the three and six months ended June 30, 2017 related to assets measured at fair value on a recurring basis using significant unobservable inputs (in thousands): Available for Sale Securities Municipal and other tax-exempt securities Other debt securities Residential mortgage loans held for sale Balance, March 31, 2017 $ 5,722 $ 4,153 $ 12,679 Transfer to Level 3 from Level 2 1 — — 853 Purchases — — — Proceeds from sales — — (1,030 ) Redemptions and distributions (1,100 ) — — Gain (loss) recognized in earnings: Mortgage banking revenue — — 233 Other comprehensive income (loss): Net change in unrealized gain (loss) 33 (1 ) — Balance, June 30, 2017 $ 4,655 $ 4,152 $ 12,735 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. Available for Sale Securities Municipal and other tax-exempt Other debt securities Residential mortgage loans held for sale Balance, Dec. 31, 2016 $ 5,789 $ 4,152 $ 11,617 Transfer to Level 3 from Level 2 1 — — 2,740 Purchases — — — Proceeds from sales — — (1,702 ) Redemptions and distributions (1,100 ) — — Gain (loss) recognized in earnings: Mortgage banking revenue — — 80 Other comprehensive income (loss): Net change in unrealized gain (loss) (34 ) — — Balance, June 30, 2017 $ 4,655 $ 4,152 $ 12,735 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. The following represents the changes for the three and six months ended June 30, 2016 related to assets measured at fair value on a recurring basis using significant unobservable inputs (in thousands): Available for Sale Securities Municipal and other tax-exempt securities Other debt securities Residential mortgage loans held for sale Balance, March 31, 2016 $ 9,614 $ 4,151 $ 8,099 Transfer to Level 3 from Level 2 1 — — 3,080 Purchases — — — Proceeds from sales — — (1,249 ) Redemptions and distributions — — — Gain (loss) recognized in earnings: Mortgage banking revenue — — (181 ) Other comprehensive income (loss): Net change in unrealized gain (loss) (14 ) — — Balance, June 30, 2016 $ 9,600 $ 4,151 $ 9,749 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. Available for Sale Securities Municipal and other tax-exempt Other debt securities Residential mortgage loans held for sale Balance, Dec. 31, 2015 $ 9,610 $ 4,151 $ 7,874 Transfer to Level 3 from Level 2 1 — — 3,540 Purchases — — — Proceeds from sales — — (1,362 ) Redemptions and distributions — — — Gain (loss) recognized in earnings Mortgage banking revenue — — (303 ) Other comprehensive income (loss): Net change in unrealized gain (loss) (10 ) — — Balance, June 30, 2016 $ 9,600 $ 4,151 $ 9,749 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 Inputs, Fair Value Measured On a Recurring Basis, Quantitative Information [Table Text Block]	A summary of quantitative information about assets measured at fair value on a recurring basis using Significant Unobservable Inputs (Level 3) as of June 30, 2017 follows (in thousands): Par Value Amortized Cost/Unpaid Principal Balance Fair Value Valuation Technique(s) Unobservable Input Range (Weighted Average) Available for sale securities Municipal and other tax-exempt securities $ 5,095 $ 5,067 $ 4,655 Discounted cash flows 1 Interest rate spread 5.98%-5.98% (5.98%) 2 90.00%-94.90% (92.93%) 3 Other debt securities 4,400 4,400 4,152 Discounted cash flows 1 Interest rate spread 5.41%-6.72% (6.57%) 4 94.31% - 94.38 (94.37%) 3 Residential mortgage loans held for sale N/A 13,274 12,563 Quoted prices of loans sold in securitization transactions, with a liquidity discount applied Liquidity discount applied to the market value of a mortgage loans qualifying for sale to U.S. government agencies. 94.64% 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 360 to 446 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 3 percent . A summary of quantitative information about Recurring Fair Value Measurements based on Significant Unobservable Inputs (Level 3) as of December 31, 2016 follows (in thousands): Par Value Amortized Fair Value Valuation Technique(s) Unobservable Input Range (Weighted Average) Available for sale securities Municipal and other tax-exempt securities $ 6,195 $ 6,163 $ 5,789 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 a 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 less than 1 percent . A summary of quantitative information about Recurring Fair Value Measurements based on Significant Unobservable Inputs (Level 3) as of June 30, 2016 follows (in thousands): Par Value Amortized Cost Fair Value Valuation Technique(s) Unobservable Input Range (Weighted Average) Available for sale securities Municipal and other tax-exempt securities $ 10,370 $ 10,312 $ 9,600 Discounted cash flows 1 Interest rate spread 5.34%-5.64% (5.60%) 2 90.00%-93.28% (92.58%) 3 Other debt securities 4,400 4,400 4,151 Discounted cash flows 1 Interest rate spread 5.51%-5.96% (5.91%) 4 94.32% - 94.34 (94.34%) 3 Residential mortgage loans held for sale N/A 10,518 9,749 Quoted prices of loans sold in securitization transactions, with a liquidity discount applied Liquidity discount applied to the market value of a mortgage loans qualifying for sale to U.S. government agencies. 92.69% 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 474 to 513 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 percent .
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) during the period. The carrying value represents only those assets with a balance at June 30, 2017 for which the fair value was adjusted during the six months ended June 30, 2017 : Fair Value Adjustments for the Carrying Value at June 30, 2017 Three Months Ended Six Months Ended 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 Gross charge-offs against allowance for loan losses Net losses and expenses of repossessed assets, net Impaired loans $ — $ 464 $ 3,570 $ 232 $ — $ 676 $ — Real estate and other repossessed assets — 3,488 530 — 772 — 906 The following represents the carrying value of assets measured at fair value on a non-recurring basis (and related losses) during the period. The carrying value represents only those assets with a balance at June 30, 2016 for which the fair value was adjusted during the six months ended June 30, 2016 : Carrying Value at June 30, 2016 Fair Value Adjustments for the Three Months Ended Six Months Ended 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 Gross charge-offs against allowance for loan losses Net losses and expenses of repossessed assets, net Impaired loans $ — $ 634 $ 42,342 $ 7,041 $ — $ 29,186 $ — Real estate and other repossessed assets — 5,709 1,693 — 751 — 1,068
Fair Value Inputs, Fair Value Measured On a Nonrecurring Basis, 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 June 30, 2017 follows (in thousands): Fair Value Valuation Technique(s) Unobservable Input Range (Weighted Average) Impaired loans $ 3,570 Discounted cash flows Recoverable oil and gas reserves, forward-looking commodity prices, estimated operating costs 75% - 90% (83%) 1 Real estate and other repossessed assets 530 Appraised value, as adjusted Marketability adjustment off appraised value 2 65% - 88% (80%) 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 June 30, 2016 follows (in thousands): Fair Value Valuation Technique(s) Unobservable Input Range (Weighted Average) Impaired loans $ 42,342 Discounted cash flows Recoverable oil and gas reserves, forward-looking commodity prices, estimated operating costs 25% - 71% (58%) 1 Real estate and other repossessed assets 1,693 Appraised value, as adjusted Marketability adjustments off appraised value2 68% - 80% (71%) 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.
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 basis as of June 30, 2017 (dollars in thousands): Carrying Value Estimated Fair Value Quoted Prices in Active Markets for Identical Instruments (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs Cash and due from banks $ 561,587 $ 561,587 $ 561,587 $ — $ — Interest-bearing cash and cash equivalents 2,078,831 2,078,831 2,078,831 — — Trading securities: — U.S. government agency debentures 20,954 20,954 — 20,954 — U.S. government agency residential mortgage-backed securities 365,171 365,171 — 365,171 — Municipal and other tax-exempt securities 45,444 45,444 — 45,444 — Other trading securities 9,845 9,845 — 9,845 — Total trading securities 441,414 441,414 — 441,414 — Investment securities: Municipal and other tax-exempt securities 267,375 270,531 — 270,531 — U.S. government agency residential mortgage-backed securities 18,035 18,642 — 18,642 — Other debt securities 205,016 226,502 — 226,502 — Total investment securities 490,426 515,675 — 515,675 — Available for sale securities: U.S. Treasury 998 998 998 — — Municipal and other tax-exempt securities 32,765 32,765 — 28,110 4,655 U.S. government agency residential mortgage-backed securities 5,382,377 5,382,377 — 5,382,377 — Privately issued residential mortgage-backed securities 103,383 103,383 — 103,383 — Commercial mortgage-backed securities guaranteed by U.S. government agencies 2,782,070 2,782,070 — 2,782,070 — Other debt securities 4,152 4,152 — — 4,152 Perpetual preferred stock 16,568 16,568 — 16,568 — Equity securities and mutual funds 18,728 18,728 3,516 15,212 — Total available for sale securities 8,341,041 8,341,041 4,514 8,327,720 8,807 Fair value option securities – U.S. government agency residential mortgage-backed securities 445,169 445,169 — 445,169 — Residential mortgage loans held for sale 287,259 287,259 — 274,524 12,735 Loans: Commercial 10,637,955 10,413,704 — — 10,413,704 Commercial real estate 3,688,592 3,636,365 — — 3,636,365 Residential mortgage 1,939,198 1,950,577 — — 1,950,577 Personal 917,900 909,055 — — 909,055 Total loans 17,183,645 16,909,701 — — 16,909,701 Allowance for loan losses (250,061 ) — — — — Loans, net of allowance 16,933,584 16,909,701 — — 16,909,701 Mortgage servicing rights 245,239 245,239 — — 245,239 Derivative instruments with positive fair value, net of cash collateral 280,289 280,289 46,366 233,923 — Deposits with no stated maturity 20,120,352 20,120,352 — — 20,120,352 Time deposits 2,196,122 2,164,115 — — 2,164,115 Other borrowed funds 5,696,666 5,664,273 — — 5,664,273 Subordinated debentures 144,658 147,204 — 147,204 — Derivative instruments with negative fair value, net of cash collateral 285,819 285,819 20,915 264,904 — 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 basis as of December 31, 2016 (dollars in thousands): Carrying Value Estimated Fair Value Quoted Prices in Active Markets for Identical Instruments (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs 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 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 collateral 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 collateral 664,531 664,531 6,972 657,559 — 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 basis as of June 30, 2016 (dollars in thousands): Carrying Value Estimated Fair Value Quoted Prices in Active Markets for Identical Instruments (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs Cash and due from banks $ 498,713 $ 498,713 $ 498,713 $ — $ — Interest-bearing cash and cash equivalents 1,907,838 1,907,838 1,907,838 — — Trading securities: — U.S. government agency debentures 18,909 18,909 — 18,909 — U.S. government agency residential mortgage-backed securities 122,306 122,306 — 122,306 — Municipal and other tax-exempt securities 52,721 52,721 — 52,721 — Other trading securities 17,686 17,686 — 17,686 — Total trading securities 211,622 211,622 — 211,622 — Investment securities: Municipal and other tax-exempt securities 334,551 340,700 — 340,700 — U.S. government agency residential mortgage-backed securities 23,750 25,233 — 25,233 — Other debt securities 202,410 233,129 — 233,129 — Total investment securities 560,711 599,062 — 599,062 — Available for sale securities: U.S. Treasury 1,004 1,004 1,004 — — Municipal and other tax-exempt securities 50,262 50,262 — 40,662 9,600 U.S. government agency residential mortgage-backed securities 5,700,268 5,700,268 — 5,700,268 — Privately issued residential mortgage-backed securities 126,313 126,313 — 126,313 — Commercial mortgage-backed securities guaranteed by U.S. government agencies 2,911,946 2,911,946 — 2,911,946 — Other debt securities 4,151 4,151 — — 4,151 Perpetual preferred stock 17,931 17,931 — 17,931 — Equity securities and mutual funds 18,814 18,814 3,785 15,029 — Total available for sale securities 8,830,689 8,830,689 4,789 8,812,149 13,751 Fair value option securities: U.S. Treasury 25,306 25,306 25,306 — — U.S. government agency residential mortgage-backed securities 237,959 237,959 — 237,959 — Total fair value option securities 263,265 263,265 25,306 237,959 — Residential mortgage loans held for sale 430,728 430,728 — 420,979 9,749 Loans: Commercial 10,356,437 10,172,701 — — 10,172,701 Commercial real estate 3,581,966 3,563,378 — — 3,563,378 Residential mortgage 1,880,923 1,913,208 — — 1,913,208 Personal 587,423 582,353 — — 582,353 Total loans 16,406,749 16,231,640 — — 16,231,640 Allowance for loan losses (243,259 ) — — — — Loans, net of allowance 16,163,490 16,231,640 — — 16,231,640 Mortgage servicing rights 190,747 190,747 — — 190,747 Derivative instruments with positive fair value, net of cash collateral 883,673 883,673 7,246 876,427 — Deposits with no stated maturity 18,512,740 18,512,740 — — 18,512,740 Time deposits 2,247,061 2,252,212 — — 2,252,212 Other borrowed funds 6,360,199 6,342,885 — — 6,342,885 Subordinated debentures 371,812 371,808 — 150,234 221,574 Derivative instruments with negative fair value, net of cash collateral 719,159 719,159 4,808 714,351 —
Fair Value Inputs, Financial Instruments, Quantitative Information [Table Text Block]	Range of Contractual Yields Average Re-pricing (in years) Discount Rate Minimum Maximum Average Minimum Maximum June 30, 2017 Commercial 0.38 % 30.00 % 0.64 0.71 % 4.56 % Commercial real estate 0.38 % 18.00 % 0.77 1.03 % 4.31 % Residential mortgage 1.74 % 18.00 % 2.18 1.75 % 4.19 % Consumer 0.25 % 21.00 % 0.28 0.70 % 4.68 % Time deposits 0.03 % 10.00 % 1.91 1.81 % 2.12 % Other borrowings 0.25 % 3.58 % 0.02 1.06 % 3.69 % Subordinated debentures 5.38 % 5.38 % 16.90 4.89 % 4.89 % 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 % Consumer 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 6.11 % 6.11 % June 30, 2016 Commercial 0.38 % 30.00 % 0.69 0.55 % 3.68 % Commercial real estate 0.38 % 18.00 % 0.73 0.80 % 3.65 % Residential mortgage 1.70 % 18.00 % 1.97 1.25 % 3.75 % Consumer 0.25 % 21.00 % 0.35 0.71 % 3.91 % Time deposits 0.03 % 9.64 % 2.15 1.16 % 1.43 % Other borrowings 0.25 % 3.28 % 0.02 0.30 % 2.92 % Subordinated debentures 1.32 % 5.38 % 8.35 2.16 % 5.38 %

Federal and State Income Taxe31

Federal and State Income Taxes Federal and State Income Taes (Tables)	6 Months Ended
	Jun. 30, 2017
Income Tax Disclosure [Abstract]
Schedule of Effective Income Tax Rate Reconciliation [Table Text Block]	The reconciliations of income (loss) attributable to continuing operations at the U.S. federal statutory tax rate to income tax expense are as follows (in thousands): Three Months Ended Six Months Ended 2017 2016 2017 2016 Amount: Federal statutory tax $ 47,800 $ 33,869 $ 92,168 $ 55,715 Tax exempt revenue (3,224 ) (2,568 ) (6,335 ) (5,100 ) Effect of state income taxes, net of federal benefit 2,944 1,557 5,389 3,858 Utilization of tax credits: Low-income housing tax credit, net of amortization (526 ) (572 ) (2,249 ) (1,882 ) Other tax credits (363 ) (521 ) (727 ) (1,042 ) Bank-owned life insurance (775 ) (810 ) (1,547 ) (1,601 ) Share-based compensation 1,636 — (2,301 ) — Other, net 213 (458 ) 1,410 1,977 Total income tax expense $ 47,705 $ 30,497 $ 85,808 $ 51,925 Three Months Ended Six Months Ended 2017 2016 2017 2016 Percent of pretax income: Federal statutory tax 35.0 % 35.0 % 35.0 % 35.0 % Tax exempt revenue (2.4 ) (2.7 ) (2.4 ) (3.2 ) Effect of state income taxes, net of federal benefit 2.2 1.6 2.0 2.4 Utilization of tax credits: Low-income housing tax credit, net of amortization (0.4 ) (0.6 ) (0.8 ) (1.2 ) Other tax credits (0.3 ) (0.5 ) (0.3 ) (0.6 ) Bank-owned life insurance (0.6 ) (0.8 ) (0.6 ) (1.0 ) Share-based compensation 1.2 — (0.9 ) — Other, net 0.2 (0.5 ) 0.6 1.2 Total 34.9 % 31.5 % 32.6 % 32.6 %

Significant Accounting Polici32

Significant Accounting Policies Loans and Allowance for Credit Losses (Details)	6 Months Ended
	Jun. 30, 2017
Loans and Allowance for Credit Losses [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 and Allowances for Credit Losses, Minimum No of Days After Which Past Due Non-Risk Graded Loans Are Charged Off	60 days
Loans and Allowances for Credit Losses, Maximum No 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 Polici33

Significant Accounting Policies Newly Adopted and Pending Accounting Pronouncements (Details)	6 Months Ended
	Jun. 30, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Percentage of gross revenue of Transaction Card Revenue and Fiduciary and Asset Management Revenue	19.00%
Percentage of fees and commission revenue composed of Transaction Card Revenue and Fiduciary and Asset Management Revenue	43.00%

Trading Securities (Details)

Trading Securities (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016	Jun. 30, 2016
Schedule of Trading Securities [Line Items]
Trading Securities, Fair Value	$ 441,414	$ 337,628	$ 211,622
Trading Securities, Net Unrealized Gain (Loss)	(986)	738	786
U.S. government agency debentures
Schedule of Trading Securities [Line Items]
Trading Securities, Fair Value	20,954	6,234	18,909
Trading Securities, Net Unrealized Gain (Loss)	(9)	(4)	(8)
U.S. government agency residential mortgage-backed securities
Schedule of Trading Securities [Line Items]
Trading Securities, Fair Value	365,171	310,067	122,306
Trading Securities, Net Unrealized Gain (Loss)	(1,032)	635	363
Municipal and other tax-exempt securities
Schedule of Trading Securities [Line Items]
Trading Securities, Fair Value	45,444	14,427	52,721
Trading Securities, Net Unrealized Gain (Loss)	230	50	262
Other trading securities
Schedule of Trading Securities [Line Items]
Trading Securities, Fair Value	9,845	6,900	17,686
Trading Securities, Net Unrealized Gain (Loss)	$ (175)	$ 57	$ 169

Investment (Held-to-Maturity) S

Investment (Held-to-Maturity) Securities (Details) $ in Thousands		6 Months Ended
		Jun. 30, 2017USD ($)		Dec. 31, 2016USD ($)		Jun. 30, 2016USD ($)
Schedule of Investment (Held-to-Maturity) Securities [Line Items]
Investments Securities, Amortized Cost		$ 490,426		$ 546,145		$ 560,711
Investment Securities, fair value		515,675		565,493		599,062
Investment Securities, Gross Unrealized Gain		26,092	[1]	21,154	[2]	38,440	[3]
Investment Securities, Gross Unrealized Loss		(843)	[1]	(1,806)	[2]	(89)	[3]
Investment Securities, Debt Maturities, Net Carrying Value [Abstract]
Investments Securities, Debt Maturities, Amortized Cost		490,426		546,145		560,711
Investment Securities, Debt Maturities, Fair Value, Rolling Maturity [Abstract]
Investment Securities, Debt Maturities, Fair Value		$ 515,675		565,493		599,062
Investment Securities, Debt Maturities, Nominal Yield [Abstract]
Investment Securities, Debt Maturities, Nominal Yield		3.73%
Investment Securities, Pledged as Collateral [Abstract]
Investment Securities, Pledged as Collateral, Amortized Cost		$ 251,684		322,208		287,166
Investment Securities, Pledged as Collateral, Fair Value		$ 255,097		$ 323,808		$ 293,625
Investment Securities, Continuous Unrealized Loss Position, Qualitative Disclosure [Abstract]
Investment Securities, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions		105		193		20
Investment Securities, Continuous Unrealized Loss Position, Fair Value [Abstract]
Investment Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value		$ 123,272		$ 236,070		$ 11,915
Investment Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		3,000		5,188		5,236
Investment Securities, Continuous Unrealized Loss Position, Fair Value		126,272		241,258		17,151
Investment Securities, Continuous Unrealized Loss Position, Aggregate Losses [Abstract]
Investment Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		764		1,709		20
Investment Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		79		97		69
Investment Securities, Continuous Unrealized Loss Position, Accumulated Loss		843		1,806		89
Fixed Maturity Securities [Member]
Investment Securities, Debt Maturities, Net Carrying Value [Abstract]
Investment Securities, Debt Maturities, Less than One Year, Net Carrying Value		104,701
Investment Securities, Debt Maturities, One to Five Years, Net Carrying Value		168,198
Investment Securities, Debt Maturities, Six to Ten Years, Net Carrying Value		141,018
Investment Securities, Debt Maturities, Over Ten Years, Net Carrying Value		58,474
Investment Securities, Debt Maturities, Single Maturity Date, Net Carrying Value		472,391
Investment Securities, Debt Maturities, Fair Value, Rolling Maturity [Abstract]
Investment Securities, Debt Maturities, Less Than One Year, Fair Value		104,918
Investment Securities, Debt Maturities, One to Five Years, Fair Value		171,887
Investment Securities, Debt Maturities, Six to Ten Years, Fair Value		159,635
Investment Securities, Debt Maturities, Over Ten Years, Fair Value		60,593
Investment Securities, Debt Maturities, Single Maturity Date, Fair Value		$ 497,033
Investment Securities, Debt Maturities, Nominal Yield [Abstract]
Investment Securities, Debt Maturities, Less Than One Year, Nominal Yield		1.95%
Investment Securities, Debt Maturities, One to Five Years, Nominal Yield		2.89%
Investment Securities, Debt Maturities, Six to Ten Years, Nominal Yield		5.69%
Investment Securities, Debt Maturities, Over Ten Years, Nominal Yield		4.90%
Investment Securities, Debt Maturities, Nominal Yield		3.77%
Investment Securities, Debt Maturities, Weighted Average Maturity	[4]	4.83
Municipal and other tax-exempt securities
Schedule of Investment (Held-to-Maturity) Securities [Line Items]
Investments Securities, Amortized Cost		$ 267,375		320,364		334,551
Investment Securities, fair value		270,531		321,225		340,700
Investment Securities, Gross Unrealized Gain		3,384	[1]	2,272	[2]	6,234	[3]
Investment Securities, Gross Unrealized Loss		(228)	[1]	(1,411)	[2]	(85)	[3]
Investment Securities, Debt Maturities, Net Carrying Value [Abstract]
Investment Securities, Debt Maturities, Less than One Year, Net Carrying Value		90,415
Investment Securities, Debt Maturities, One to Five Years, Net Carrying Value		122,560
Investment Securities, Debt Maturities, Six to Ten Years, Net Carrying Value		10,739
Investment Securities, Debt Maturities, Over Ten Years, Net Carrying Value		43,661
Investment Securities, Debt Maturities, Single Maturity Date, Net Carrying Value		267,375
Investments Securities, Debt Maturities, Amortized Cost		267,375		320,364		334,551
Investment Securities, Debt Maturities, Fair Value, Rolling Maturity [Abstract]
Investment Securities, Debt Maturities, Less Than One Year, Fair Value		90,436
Investment Securities, Debt Maturities, One to Five Years, Fair Value		122,914
Investment Securities, Debt Maturities, Six to Ten Years, Fair Value		11,220
Investment Securities, Debt Maturities, Over Ten Years, Fair Value		45,961
Investment Securities, Debt Maturities, Single Maturity Date, Fair Value		270,531
Investment Securities, Debt Maturities, Fair Value		$ 270,531		$ 321,225		$ 340,700
Investment Securities, Debt Maturities, Nominal Yield [Abstract]
Investment Securities, Debt Maturities, Less Than One Year, Nominal Yield	[5]	1.66%
Investment Securities, Debt Maturities, One to Five Years, Nominal Yield	[5]	2.12%
Investment Securities, Debt Maturities, Six to Ten Years, Nominal Yield	[5]	4.88%
Investment Securities, Debt Maturities, Over Ten Years, Nominal Yield	[5]	5.05%
Investment Securities, Debt Maturities, Nominal Yield	[5]	2.55%
Investment Securities, Debt Maturities, Weighted Average Maturity	[4]	3.48
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 Positions		82		151		19
Investment Securities, Continuous Unrealized Loss Position, Fair Value [Abstract]
Investment Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value		$ 111,078		$ 219,892		$ 11,915
Investment Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		3,000		4,333		4,378
Investment Securities, Continuous Unrealized Loss Position, Fair Value		114,078		224,225		16,293
Investment Securities, Continuous Unrealized Loss Position, Aggregate Losses [Abstract]
Investment Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		149		1,316		20
Investment Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		79		95		65
Investment Securities, Continuous Unrealized Loss Position, Accumulated Loss		228		1,411		85
Other debt securities
Schedule of Investment (Held-to-Maturity) Securities [Line Items]
Investments Securities, Amortized Cost		205,016		205,004		202,410
Investment Securities, fair value		226,502		222,795		233,129
Investment Securities, Gross Unrealized Gain		22,040	[1]	18,115	[2]	30,723	[3]
Investment Securities, Gross Unrealized Loss		(554)	[1]	(324)	[2]	(4)	[3]
Investment Securities, Debt Maturities, Net Carrying Value [Abstract]
Investment Securities, Debt Maturities, Less than One Year, Net Carrying Value		14,286
Investment Securities, Debt Maturities, One to Five Years, Net Carrying Value		45,638
Investment Securities, Debt Maturities, Six to Ten Years, Net Carrying Value		130,279
Investment Securities, Debt Maturities, Over Ten Years, Net Carrying Value		14,813
Investment Securities, Debt Maturities, Single Maturity Date, Net Carrying Value		205,016
Investments Securities, Debt Maturities, Amortized Cost		205,016		205,004		202,410
Investment Securities, Debt Maturities, Fair Value, Rolling Maturity [Abstract]
Investment Securities, Debt Maturities, Less Than One Year, Fair Value		14,482
Investment Securities, Debt Maturities, One to Five Years, Fair Value		48,973
Investment Securities, Debt Maturities, Six to Ten Years, Fair Value		148,415
Investment Securities, Debt Maturities, Over Ten Years, Fair Value		14,632
Investment Securities, Debt Maturities, Single Maturity Date, Fair Value		226,502
Investment Securities, Debt Maturities, Fair Value		$ 226,502		$ 222,795		$ 233,129
Investment Securities, Debt Maturities, Nominal Yield [Abstract]
Investment Securities, Debt Maturities, Less Than One Year, Nominal Yield		3.84%
Investment Securities, Debt Maturities, One to Five Years, Nominal Yield		4.95%
Investment Securities, Debt Maturities, Six to Ten Years, Nominal Yield		5.75%
Investment Securities, Debt Maturities, Over Ten Years, Nominal Yield		4.46%
Investment Securities, Debt Maturities, Nominal Yield		5.35%
Investment Securities, Debt Maturities, Weighted Average Maturity	[4]	6.59
Investment Securities, Continuous Unrealized Loss Position, Qualitative Disclosure [Abstract]
Investment Securities, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions		22		41		1
Investment Securities, Continuous Unrealized Loss Position, Fair Value [Abstract]
Investment Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value		$ 8,384		$ 11,820		$ 0
Investment Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		0		855		858
Investment Securities, Continuous Unrealized Loss Position, Fair Value		8,384		12,675		858
Investment Securities, Continuous Unrealized Loss Position, Aggregate Losses [Abstract]
Investment Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		554		322		0
Investment Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		0		2		4
Investment Securities, Continuous Unrealized Loss Position, Accumulated Loss		554		324		4
U.S. government agency residential mortgage-backed securities
Investment Securities, Debt Maturities, Net Carrying Value [Abstract]
Investment Securities, Debt Maturities, without Single Maturity Date, Net Carrying Value		18,035
Investment Securities, Debt Maturities, Fair Value, Rolling Maturity [Abstract]
Investment Securities, Debt Maturities, without Single Maturity Date, Fair Value		$ 18,642
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 255 days
U.S. government agency residential mortgage-backed securities | Other
Schedule of Investment (Held-to-Maturity) Securities [Line Items]
Investments Securities, Amortized Cost		$ 18,035		20,777		23,750
Investment Securities, fair value		18,642		21,473		25,233
Investment Securities, Gross Unrealized Gain		668	[1]	767	[2]	1,483	[3]
Investment Securities, Gross Unrealized Loss		(61)	[1]	(71)	[2]	0	[3]
Investment Securities, Debt Maturities, Net Carrying Value [Abstract]
Investments Securities, Debt Maturities, Amortized Cost		18,035		20,777		23,750
Investment Securities, Debt Maturities, Fair Value, Rolling Maturity [Abstract]
Investment Securities, Debt Maturities, Fair Value		$ 18,642		$ 21,473		$ 25,233
Investment Securities, Continuous Unrealized Loss Position, Qualitative Disclosure [Abstract]
Investment Securities, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions		1		1		0
Investment Securities, Continuous Unrealized Loss Position, Fair Value [Abstract]
Investment Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value		$ 3,810		$ 4,358		$ 0
Investment Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		0		0		0
Investment Securities, Continuous Unrealized Loss Position, Fair Value		3,810		4,358		0
Investment Securities, Continuous Unrealized Loss Position, Aggregate Losses [Abstract]
Investment Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		61		71		0
Investment Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		0		0		0
Investment Securities, Continuous Unrealized Loss Position, Accumulated Loss		$ 61		$ 71		$ 0
[1]	Gross unrealized gains and losses are not recognized in Accumulated Other Comprehensive Income "AOCI" in the Consolidated Balance Sheets.
[2]	Gross unrealized gains and losses are not recognized in AOCI in the Consolidated Balance Sheets.
[3]	Gross unrealized gains and losses are not recognized in AOCI in the Consolidated Balance Sheets.
[4]	Expected maturities may differ from contractual maturities, because borrowers may have the right to call or prepay obligations with or without penalty.
[5]	Calculated on a taxable equivalent basis using a 39 percent effective tax rate.
[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) $ in Thousands		3 Months Ended				6 Months Ended
		Jun. 30, 2017USD ($)		Jun. 30, 2016USD ($)		Jun. 30, 2017USD ($)		Jun. 30, 2016USD ($)		Dec. 31, 2016USD ($)
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost		$ 8,325,000		$ 8,635,304		$ 8,325,000		$ 8,635,304		$ 8,691,728
Available-for-sale Securities, Fair Value		8,341,041		8,830,689		8,341,041		8,830,689		8,676,829
Available-for-sale Securities, Gross Unrealized Gain		65,740	[1]	198,378	[2]	65,740	[1]	198,378	[2]	60,165	[3]
Available-for-sale Securities, Gross Unrealized Loss		(49,699)	[1]	(2,217)	[2]	(49,699)	[1]	(2,217)	[2]	(74,846)	[3]
Available-for-Sale Securities, Other Than Temporary Impairments		0	[4]	(776)	[5]	0	[4]	(776)	[5]	(218)	[6]
Available-for-sale Securities, Debt Maturities, Amortized Cost Basis, Rolling Maturity [Abstract]
Available-for-sale Securities, Debt Maturities, Amortized Cost		8,325,000		8,635,304		8,325,000		8,635,304		8,691,728
Available-for-sale Securities, Debt Maturities, Fair Value, Rolling Maturity [Abstract]
Available-for-sale Securities, Debt Maturities, Fair Value		$ 8,341,041		8,830,689		$ 8,341,041		8,830,689		8,676,829
Available-for-sale Securities, Debt Maturities, Nominal Yield [Abstract]
Available-for-sale Securities, Debt Maturities, Nominal Yield		1.90%				1.90%
Available-for-sale Securities, Gross Realized Gain (Loss), Disclosures [Abstract]
Available-for-sale Securities, Proceeds		$ 460,402		325,758		$ 700,412		795,140
Available-for-sale Securities, Gross realized gains		2,763		5,326		4,855		9,290
Available-for-sale Securities, Gross realized losses		(2,383)		0		(2,426)		0
Available-for-sale Securities, Related federal and state income tax expense		148		2,072		945		3,614
Available-for-sale Securities, Pledged as Collateral [Abstract]
Available-for-sale Securities, Pledged As Collateral, Amortized cost		6,327,666		7,502,361		6,327,666		7,502,361		7,353,116
Available-for-sale Securities, Pledged As Collateral, Fair value		$ 6,317,623		$ 7,657,916		$ 6,317,623		$ 7,657,916		$ 7,327,470
Available-for-sale Securities, Continuous Unrealized Loss Position, Qualitative Disclosure [Abstract]
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions		367		90		367		90		488
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		$ 3,818,331		$ 567,460		$ 3,818,331		$ 567,460		$ 5,231,605
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		268,886		135,093		268,886		135,093		178,249
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value		4,087,217		702,553		4,087,217		702,553		5,409,854
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		44,025		1,193		44,025		1,193		70,818
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		5,674		1,800		5,674		1,800		4,246
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss		49,699		2,993		49,699		2,993		75,064
Fixed Maturity Securities [Member]
Available-for-sale Securities, Debt Maturities, Amortized Cost Basis, Rolling Maturity [Abstract]
Available-for-sale Securities, Debt Maturities, Less than One Year, Amortized Cost Basis		68,244				68,244
Available-for-sale Securities, Debt Maturities, One to Five Years, Amortized Cost Basis		886,839				886,839
Available-for-sale Securities, Debt Maturities, Six To Ten Years, Amortized Cost Basis		1,572,763				1,572,763
Available-for-sale Securities, Debt Maturities, Over Ten Years, Amortized Cost Basis		298,982				298,982
Available-for-sale Securities, Debt Maturities, Single Maturity Date, Amortized Cost Basis		2,826,828				2,826,828
Available-for-sale Securities, Debt Maturities, Fair Value, Rolling Maturity [Abstract]
Available-for-sale Securities, Debt Maturities, Less than One Year, Fair Value		68,166				68,166
Available-for-sale Securities, Debt Maturities, One to Five Years, Fair Value		885,783				885,783
Available-for-sale Securities, Debt Maturities, Six to Ten Years, Fair Value		1,569,813				1,569,813
Available-for-sale Securities, Debt Maturities, Over Ten Years, Fair Value		296,223				296,223
Available-for-sale Securities, Debt Maturities, Single Maturity Date		$ 2,819,985				$ 2,819,985
Available-for-sale Securities, Debt Maturities, Nominal Yield [Abstract]
Available-for-sale Securities, Debt Maturities, Less than One Year, Nominal Yield		1.60%				1.60%
Available-for-sale Securities, Debt Maturities, One to Five Years, Nominal Yield		1.85%				1.85%
Available-for-sale Securities, Debt Maturities, Six To Ten Years, Nominal Yield		1.85%				1.85%
Available-for-sale Securities, Debt Maturities, Over Ten Years, Nominal Yield		1.90%				1.90%
Available-for-sale Securities, Debt Maturities, Nominal Yield		1.83%				1.83%
Available-for-sale Securities, Debt Maturities, Weighted Average Maturity	[7]	7.03				7.03
U.S. Treasury
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost		$ 1,000		1,000		$ 1,000		1,000		1,000
Available-for-sale Securities, Fair Value		998		1,004		998		1,004		999
Available-for-sale Securities, Gross Unrealized Gain		0	[1]	4	[2]	0	[1]	4	[2]	0	[3]
Available-for-sale Securities, Gross Unrealized Loss		(2)	[1]	0	[2]	(2)	[1]	0	[2]	(1)	[3]
Available-for-Sale Securities, Other Than Temporary Impairments		0	[4]	0	[5]	0	[4]	0	[5]	0	[6]
Available-for-sale Securities, Debt Maturities, Amortized Cost Basis, Rolling Maturity [Abstract]
Available-for-sale Securities, Debt Maturities, Less than One Year, Amortized Cost Basis		1,000				1,000
Available-for-sale Securities, Debt Maturities, One to Five Years, Amortized Cost Basis		0				0
Available-for-sale Securities, Debt Maturities, Six To Ten Years, Amortized Cost Basis		0				0
Available-for-sale Securities, Debt Maturities, Over Ten Years, Amortized Cost Basis		0				0
Available-for-sale Securities, Debt Maturities, Single Maturity Date, Amortized Cost Basis		1,000				1,000
Available-for-sale Securities, Debt Maturities, Amortized Cost		1,000		1,000		1,000		1,000		1,000
Available-for-sale Securities, Debt Maturities, Fair Value, Rolling Maturity [Abstract]
Available-for-sale Securities, Debt Maturities, Less than One Year, Fair Value		998				998
Available-for-sale Securities, Debt Maturities, One to Five Years, Fair Value		0				0
Available-for-sale Securities, Debt Maturities, Six to Ten Years, Fair Value		0				0
Available-for-sale Securities, Debt Maturities, Over Ten Years, Fair Value		0				0
Available-for-sale Securities, Debt Maturities, Single Maturity Date		998				998
Available-for-sale Securities, Debt Maturities, Fair Value		$ 998		$ 1,004		$ 998		$ 1,004		$ 999
Available-for-sale Securities, Debt Maturities, Nominal Yield [Abstract]
Available-for-sale Securities, Debt Maturities, Less than One Year, Nominal Yield		0.87%				0.87%
Available-for-sale Securities, Debt Maturities, One to Five Years, Nominal Yield		0.00%				0.00%
Available-for-sale Securities, Debt Maturities, Six To Ten Years, Nominal Yield		0.00%				0.00%
Available-for-sale Securities, Debt Maturities, Over Ten Years, Nominal Yield		0.00%				0.00%
Available-for-sale Securities, Debt Maturities, Nominal Yield		0.87%				0.87%
Available-for-sale Securities, Debt Maturities, Weighted Average Maturity	[7]	0.55				0.55
Available-for-sale Securities, Continuous Unrealized Loss Position, Qualitative Disclosure [Abstract]
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions		1		0		1		0		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		$ 997		$ 0		$ 997		$ 0		$ 999
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		0		0		0		0		0
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value		997		0		997		0		999
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		2		0		2		0		1
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		0		0		0		0		0
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss		2		0		2		0		1
Municipal and other tax-exempt securities
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost		32,885		50,170		32,885		50,170		41,050
Available-for-sale Securities, Fair Value		32,765		50,262		32,765		50,262		40,993
Available-for-sale Securities, Gross Unrealized Gain		293	[1]	805	[2]	293	[1]	805	[2]	343	[3]
Available-for-sale Securities, Gross Unrealized Loss		(413)	[1]	(713)	[2]	(413)	[1]	(713)	[2]	(400)	[3]
Available-for-Sale Securities, Other Than Temporary Impairments		0	[4]	0	[5]	0	[4]	0	[5]	0	[6]
Available-for-sale Securities, Debt Maturities, Amortized Cost Basis, Rolling Maturity [Abstract]
Available-for-sale Securities, Debt Maturities, Less than One Year, Amortized Cost Basis		8,981				8,981
Available-for-sale Securities, Debt Maturities, One to Five Years, Amortized Cost Basis		6,380				6,380
Available-for-sale Securities, Debt Maturities, Six To Ten Years, Amortized Cost Basis		1,028				1,028
Available-for-sale Securities, Debt Maturities, Over Ten Years, Amortized Cost Basis		16,496				16,496
Available-for-sale Securities, Debt Maturities, Single Maturity Date, Amortized Cost Basis		32,885				32,885
Available-for-sale Securities, Debt Maturities, Amortized Cost		32,885		50,170		32,885		50,170		41,050
Available-for-sale Securities, Debt Maturities, Fair Value, Rolling Maturity [Abstract]
Available-for-sale Securities, Debt Maturities, Less than One Year, Fair Value		9,021				9,021
Available-for-sale Securities, Debt Maturities, One to Five Years, Fair Value		6,497				6,497
Available-for-sale Securities, Debt Maturities, Six to Ten Years, Fair Value		1,081				1,081
Available-for-sale Securities, Debt Maturities, Over Ten Years, Fair Value		16,166				16,166
Available-for-sale Securities, Debt Maturities, Single Maturity Date		32,765				32,765
Available-for-sale Securities, Debt Maturities, Fair Value		$ 32,765		$ 50,262		$ 32,765		$ 50,262		$ 40,993
Available-for-sale Securities, Debt Maturities, Nominal Yield [Abstract]
Available-for-sale Securities, Debt Maturities, Less than One Year, Nominal Yield	[8]	4.24%				4.24%
Available-for-sale Securities, Debt Maturities, One to Five Years, Nominal Yield	[8]	3.91%				3.91%
Available-for-sale Securities, Debt Maturities, Six To Ten Years, Nominal Yield	[8]	6.72%				6.72%
Available-for-sale Securities, Debt Maturities, Over Ten Years, Nominal Yield	[8],[9]	2.28%				2.28%
Available-for-sale Securities, Debt Maturities, Nominal Yield	[8]	3.27%				3.27%
Available-for-sale Securities, Debt Maturities, Weighted Average Maturity	[7]	8.87				8.87
Available-for-sale Securities, Debt Maturities, Effective tax rate for nominal yield calculation		39.00%				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 Positions		13		17		13		17		24
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		$ 1,957		$ 375		$ 1,957		$ 375		$ 15,666
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		4,655		10,289		4,655		10,289		4,689
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value		6,612		10,664		6,612		10,664		20,355
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		0		1		0		22
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		412		713		412		713		378
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss		413		713		413		713		400
Commercial mortgage-backed securities guaranteed by U.S. government agencies
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost		2,788,543		2,854,306		2,788,543		2,854,306		3,035,750
Available-for-sale Securities, Fair Value		2,782,070		2,911,946		2,782,070		2,911,946		3,017,933
Available-for-sale Securities, Gross Unrealized Gain		7,804	[1]	57,762	[2]	7,804	[1]	57,762	[2]	5,472	[3]
Available-for-sale Securities, Gross Unrealized Loss		(14,277)	[1]	(122)	[2]	(14,277)	[1]	(122)	[2]	(23,289)	[3]
Available-for-Sale Securities, Other Than Temporary Impairments		0	[4]	0	[5]	0	[4]	0	[5]	0	[6]
Available-for-sale Securities, Debt Maturities, Amortized Cost Basis, Rolling Maturity [Abstract]
Available-for-sale Securities, Debt Maturities, Less than One Year, Amortized Cost Basis		58,263				58,263
Available-for-sale Securities, Debt Maturities, One to Five Years, Amortized Cost Basis		880,459				880,459
Available-for-sale Securities, Debt Maturities, Six To Ten Years, Amortized Cost Basis		1,571,735				1,571,735
Available-for-sale Securities, Debt Maturities, Over Ten Years, Amortized Cost Basis		278,086				278,086
Available-for-sale Securities, Debt Maturities, Single Maturity Date, Amortized Cost Basis		2,788,543				2,788,543
Available-for-sale Securities, Debt Maturities, Amortized Cost		2,788,543		2,854,306		2,788,543		2,854,306		3,035,750
Available-for-sale Securities, Debt Maturities, Fair Value, Rolling Maturity [Abstract]
Available-for-sale Securities, Debt Maturities, Less than One Year, Fair Value		58,147				58,147
Available-for-sale Securities, Debt Maturities, One to Five Years, Fair Value		879,286				879,286
Available-for-sale Securities, Debt Maturities, Six to Ten Years, Fair Value		1,568,732				1,568,732
Available-for-sale Securities, Debt Maturities, Over Ten Years, Fair Value		275,905				275,905
Available-for-sale Securities, Debt Maturities, Single Maturity Date		2,782,070				2,782,070
Available-for-sale Securities, Debt Maturities, Fair Value		$ 2,782,070		$ 2,911,946		$ 2,782,070		$ 2,911,946		$ 3,017,933
Available-for-sale Securities, Debt Maturities, Nominal Yield [Abstract]
Available-for-sale Securities, Debt Maturities, Less than One Year, Nominal Yield		1.20%				1.20%
Available-for-sale Securities, Debt Maturities, One to Five Years, Nominal Yield		1.83%				1.83%
Available-for-sale Securities, Debt Maturities, Six To Ten Years, Nominal Yield		1.84%				1.84%
Available-for-sale Securities, Debt Maturities, Over Ten Years, Nominal Yield		1.88%				1.88%
Available-for-sale Securities, Debt Maturities, Nominal Yield		1.82%				1.82%
Available-for-sale Securities, Debt Maturities, Weighted Average Maturity	[7]	6.98				6.98
Available-for-sale Securities, Continuous Unrealized Loss Position, Qualitative Disclosure [Abstract]
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions		121		11		121		11		171
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		$ 1,388,406		$ 103,955		$ 1,388,406		$ 103,955		$ 1,904,584
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		78,828		65,857		78,828		65,857		38,875
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value		1,467,234		169,812		1,467,234		169,812		1,943,459
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		12,690		37		12,690		37		22,987
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		1,587		85		1,587		85		302
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss		14,277		122		14,277		122		23,289
Other debt securities
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost		4,400		4,400		4,400		4,400		4,400
Available-for-sale Securities, Fair Value		4,152		4,151		4,152		4,151		4,152
Available-for-sale Securities, Gross Unrealized Gain		0	[1]	0	[2]	0	[1]	0	[2]	0	[3]
Available-for-sale Securities, Gross Unrealized Loss		(248)	[1]	(249)	[2]	(248)	[1]	(249)	[2]	(248)	[3]
Available-for-Sale Securities, Other Than Temporary Impairments		0	[4]	0	[5]	0	[4]	0	[5]	0	[6]
Available-for-sale Securities, Debt Maturities, Amortized Cost Basis, Rolling Maturity [Abstract]
Available-for-sale Securities, Debt Maturities, Less than One Year, Amortized Cost Basis		0				0
Available-for-sale Securities, Debt Maturities, One to Five Years, Amortized Cost Basis		0				0
Available-for-sale Securities, Debt Maturities, Six To Ten Years, Amortized Cost Basis		0				0
Available-for-sale Securities, Debt Maturities, Over Ten Years, Amortized Cost Basis		4,400				4,400
Available-for-sale Securities, Debt Maturities, Single Maturity Date, Amortized Cost Basis		4,400				4,400
Available-for-sale Securities, Debt Maturities, Amortized Cost		4,400		4,400		4,400		4,400		4,400
Available-for-sale Securities, Debt Maturities, Fair Value, Rolling Maturity [Abstract]
Available-for-sale Securities, Debt Maturities, Less than One Year, Fair Value		0				0
Available-for-sale Securities, Debt Maturities, One to Five Years, Fair Value		0				0
Available-for-sale Securities, Debt Maturities, Six to Ten Years, Fair Value		0				0
Available-for-sale Securities, Debt Maturities, Over Ten Years, Fair Value		4,152				4,152
Available-for-sale Securities, Debt Maturities, Single Maturity Date		4,152				4,152
Available-for-sale Securities, Debt Maturities, Fair Value		$ 4,152		$ 4,151		$ 4,152		$ 4,151		$ 4,152
Available-for-sale Securities, Debt Maturities, Nominal Yield [Abstract]
Available-for-sale Securities, Debt Maturities, Less than One Year, Nominal Yield		0.00%				0.00%
Available-for-sale Securities, Debt Maturities, One to Five Years, Nominal Yield		0.00%				0.00%
Available-for-sale Securities, Debt Maturities, Six To Ten Years, Nominal Yield		0.00%				0.00%
Available-for-sale Securities, Debt Maturities, Over Ten Years, Nominal Yield	[9]	1.71%				1.71%
Available-for-sale Securities, Debt Maturities, Nominal Yield		1.71%				1.71%
Available-for-sale Securities, Debt Maturities, Weighted Average Maturity	[7]	30.16				30.16
Available-for-sale Securities, Continuous Unrealized Loss Position, Qualitative Disclosure [Abstract]
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions		2		2		2		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		$ 0		$ 0		$ 0
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		4,152		4,151		4,152		4,151		4,152
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value		4,152		4,151		4,152		4,151		4,152
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		0		0		0
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		248		249		248		249		248
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss		248		249		248		249		248
Residential Mortgage Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost		5,468,038		5,692,596		5,468,038		5,692,596		5,576,543
Available-for-sale Securities, Fair Value		5,485,760		5,826,581		5,485,760		5,826,581		5,575,921
Available-for-sale Securities, Gross Unrealized Gain		52,418	[1]	135,880	[2]	52,418	[1]	135,880	[2]	50,377	[3]
Available-for-sale Securities, Gross Unrealized Loss		(34,696)	[1]	(1,119)	[2]	(34,696)	[1]	(1,119)	[2]	(50,781)	[3]
Available-for-Sale Securities, Other Than Temporary Impairments		0	[4]	(776)	[5]	0	[4]	(776)	[5]	(218)	[6]
Available-for-sale Securities, Debt Maturities, Amortized Cost Basis, Rolling Maturity [Abstract]
Available-for-sale Securities, Debt Maturities, without Single Maturity Date, Amortized Cost Basis		5,468,038				5,468,038
Available-for-sale Securities, Debt Maturities, Amortized Cost		5,468,038		5,692,596		5,468,038		5,692,596		5,576,543
Available-for-sale Securities, Debt Maturities, Fair Value, Rolling Maturity [Abstract]
Available-for-sale Securities, Debt Maturities, without Single Maturity Date, Fair Value		5,485,760				5,485,760
Available-for-sale Securities, Debt Maturities, Fair Value		$ 5,485,760		$ 5,826,581		$ 5,485,760		$ 5,826,581		$ 5,575,921
Available-for-sale Securities, Debt Maturities, Nominal Yield [Abstract]
Available-for-sale Securities, Debt Maturities, Nominal Yield	[10]	1.94%				1.94%
Available-for-sale Securities, Debt Maturities, Average Expected Life of Mortgage-backed Securities						3 years 329 days
Available-for-sale Securities, Continuous Unrealized Loss Position, Qualitative Disclosure [Abstract]
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions		139		30		139		30		186
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		$ 2,425,303		$ 463,130		$ 2,425,303		$ 463,130		$ 3,308,229
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		180,364		53,907		180,364		53,907		129,716
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value		2,605,667		517,037		2,605,667		517,037		3,437,945
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		31,310		1,156		31,310		1,156		47,767
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		3,386		739		3,386		739		3,232
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss		34,696		1,895		34,696		1,895		50,999
U.S. government agency residential mortgage-backed securities
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost		5,381,382		5,577,287		5,381,382		5,577,287		5,475,351
Available-for-sale Securities, Fair Value		5,382,377		5,700,268		5,382,377		5,700,268		5,460,386
Available-for-sale Securities, Gross Unrealized Gain		35,691	[1]	124,064	[2]	35,691	[1]	124,064	[2]	35,800	[3]
Available-for-sale Securities, Gross Unrealized Loss		(34,696)	[1]	(1,083)	[2]	(34,696)	[1]	(1,083)	[2]	(50,765)	[3]
Available-for-Sale Securities, Other Than Temporary Impairments		0	[4]	0	[5]	0	[4]	0	[5]	0	[6]
Available-for-sale Securities, Debt Maturities, Amortized Cost Basis, Rolling Maturity [Abstract]
Available-for-sale Securities, Debt Maturities, Amortized Cost		5,381,382		5,577,287		5,381,382		5,577,287		5,475,351
Available-for-sale Securities, Debt Maturities, Fair Value, Rolling Maturity [Abstract]
Available-for-sale Securities, Debt Maturities, Fair Value		$ 5,382,377		$ 5,700,268		$ 5,382,377		$ 5,700,268		$ 5,460,386
Available-for-sale Securities, Continuous Unrealized Loss Position, Qualitative Disclosure [Abstract]
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions		139		16		139		16		180
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		$ 2,425,303		$ 447,541		$ 2,425,303		$ 447,541		$ 3,300,298
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		180,364		37,739		180,364		37,739		116,208
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value		2,605,667		485,280		2,605,667		485,280		3,416,506
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		31,310		879		31,310		879		47,593
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		3,386		204		3,386		204		3,172
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss		34,696		1,083		34,696		1,083		50,765
U.S. government agency residential mortgage-backed securities | Federal National Mortgage Association Certificates and Obligations (FNMA) [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost		3,005,920		2,908,698		3,005,920		2,908,698		3,062,525
Available-for-sale Securities, Fair Value		3,008,531		2,988,974		3,008,531		2,988,974		3,055,676
Available-for-sale Securities, Gross Unrealized Gain		24,213	[1]	80,549	[2]	24,213	[1]	80,549	[2]	25,066	[3]
Available-for-sale Securities, Gross Unrealized Loss		(21,602)	[1]	(273)	[2]	(21,602)	[1]	(273)	[2]	(31,915)	[3]
Available-for-Sale Securities, Other Than Temporary Impairments		0	[4]	0	[5]	0	[4]	0	[5]	0	[6]
Available-for-sale Securities, Debt Maturities, Amortized Cost Basis, Rolling Maturity [Abstract]
Available-for-sale Securities, Debt Maturities, Amortized Cost		3,005,920		2,908,698		3,005,920		2,908,698		3,062,525
Available-for-sale Securities, Debt Maturities, Fair Value, Rolling Maturity [Abstract]
Available-for-sale Securities, Debt Maturities, Fair Value		$ 3,008,531		$ 2,988,974		$ 3,008,531		$ 2,988,974		$ 3,055,676
Available-for-sale Securities, Continuous Unrealized Loss Position, Qualitative Disclosure [Abstract]
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions		75		4		75		4		91
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		$ 1,381,687		$ 97,910		$ 1,381,687		$ 97,910		$ 1,787,644
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		87,371		15,401		87,371		15,401		72,105
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value		1,469,058		113,311		1,469,058		113,311		1,859,749
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		20,288		267		20,288		267		30,238
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		1,314		6		1,314		6		1,677
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss		21,602		273		21,602		273		31,915
U.S. government agency residential mortgage-backed securities | Federal Home Loan Mortgage Corporation Certificates and Obligations (FHLMC) [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost		1,412,376		1,746,661		1,412,376		1,746,661		1,534,451
Available-for-sale Securities, Fair Value		1,412,472		1,785,332		1,412,472		1,785,332		1,531,116
Available-for-sale Securities, Gross Unrealized Gain		7,785	[1]	38,869	[2]	7,785	[1]	38,869	[2]	8,475	[3]
Available-for-sale Securities, Gross Unrealized Loss		(7,689)	[1]	(198)	[2]	(7,689)	[1]	(198)	[2]	(11,810)	[3]
Available-for-Sale Securities, Other Than Temporary Impairments		0	[4]	0	[5]	0	[4]	0	[5]	0	[6]
Available-for-sale Securities, Debt Maturities, Amortized Cost Basis, Rolling Maturity [Abstract]
Available-for-sale Securities, Debt Maturities, Amortized Cost		1,412,376		1,746,661		1,412,376		1,746,661		1,534,451
Available-for-sale Securities, Debt Maturities, Fair Value, Rolling Maturity [Abstract]
Available-for-sale Securities, Debt Maturities, Fair Value		$ 1,412,472		$ 1,785,332		$ 1,412,472		$ 1,785,332		$ 1,531,116
Available-for-sale Securities, Continuous Unrealized Loss Position, Qualitative Disclosure [Abstract]
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions		42		1		42		1		58
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		$ 731,853		$ 0		$ 731,853		$ 0		$ 964,017
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		16,388		22,338		16,388		22,338		18,307
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value		748,241		22,338		748,241		22,338		982,324
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		7,213		0		7,213		0		11,210
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		476		198		476		198		600
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss		7,689		198		7,689		198		11,810
U.S. government agency residential mortgage-backed securities | Government National Mortgage Association Certificates and Obligations (GNMA) [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost		938,086		921,928		938,086		921,928		878,375
Available-for-sale Securities, Fair Value		936,365		925,962		936,365		925,962		873,594
Available-for-sale Securities, Gross Unrealized Gain		3,641	[1]	4,646	[2]	3,641	[1]	4,646	[2]	2,259	[3]
Available-for-sale Securities, Gross Unrealized Loss		(5,362)	[1]	(612)	[2]	(5,362)	[1]	(612)	[2]	(7,040)	[3]
Available-for-Sale Securities, Other Than Temporary Impairments		0	[4]	0	[5]	0	[4]	0	[5]	0	[6]
Available-for-sale Securities, Debt Maturities, Amortized Cost Basis, Rolling Maturity [Abstract]
Available-for-sale Securities, Debt Maturities, Amortized Cost		938,086		921,928		938,086		921,928		878,375
Available-for-sale Securities, Debt Maturities, Fair Value, Rolling Maturity [Abstract]
Available-for-sale Securities, Debt Maturities, Fair Value		$ 936,365		$ 925,962		$ 936,365		$ 925,962		$ 873,594
Available-for-sale Securities, Continuous Unrealized Loss Position, Qualitative Disclosure [Abstract]
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions		21		11		21		11		31
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		$ 291,806		$ 349,631		$ 291,806		$ 349,631		$ 548,637
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		76,605		0		76,605		0		25,796
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value		368,411		349,631		368,411		349,631		574,433
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		3,766		612		3,766		612		6,145
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		1,596		0		1,596		0		895
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss		5,362		612		5,362		612		7,040
U.S. government agency residential mortgage-backed securities | Other
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost		25,000				25,000
Available-for-sale Securities, Fair Value		25,009				25,009
Available-for-sale Securities, Gross Unrealized Gain	[1]	52				52
Available-for-sale Securities, Gross Unrealized Loss	[1]	(43)				(43)
Available-for-Sale Securities, Other Than Temporary Impairments		0				0
Available-for-sale Securities, Debt Maturities, Amortized Cost Basis, Rolling Maturity [Abstract]
Available-for-sale Securities, Debt Maturities, Amortized Cost		25,000				25,000
Available-for-sale Securities, Debt Maturities, Fair Value, Rolling Maturity [Abstract]
Available-for-sale Securities, Debt Maturities, Fair Value		$ 25,009				$ 25,009
Available-for-sale Securities, Continuous Unrealized Loss Position, Qualitative Disclosure [Abstract]
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions		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		$ 19,957				$ 19,957
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		19,957				19,957
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		43				43
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		43				43
Privately issued residential mortgage-backed securities
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost		86,656		115,309		86,656		115,309		101,192
Available-for-sale Securities, Fair Value		103,383		126,313		103,383		126,313		115,535
Available-for-sale Securities, Gross Unrealized Gain		16,727	[1]	11,816	[2]	16,727	[1]	11,816	[2]	14,577	[3]
Available-for-sale Securities, Gross Unrealized Loss		0	[1]	(36)	[2]	0	[1]	(36)	[2]	(16)	[3]
Available-for-Sale Securities, Other Than Temporary Impairments		0	[4]	(776)	[5]	0	[4]	(776)	[5]	(218)	[6]
Available-for-sale Securities, Debt Maturities, Amortized Cost Basis, Rolling Maturity [Abstract]
Available-for-sale Securities, Debt Maturities, Amortized Cost		86,656		115,309		86,656		115,309		101,192
Available-for-sale Securities, Debt Maturities, Fair Value, Rolling Maturity [Abstract]
Available-for-sale Securities, Debt Maturities, Fair Value		$ 103,383		$ 126,313		$ 103,383		$ 126,313		$ 115,535
Available-for-sale Securities, Continuous Unrealized Loss Position, Qualitative Disclosure [Abstract]
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions		0		14	[11]	0		14	[11]	6	[12]
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		$ 15,589	[11]	$ 0		$ 15,589	[11]	$ 7,931	[12]
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		0		16,168	[11]	0		16,168	[11]	13,508	[12]
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value		0		31,757	[11]	0		31,757	[11]	21,439	[12]
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		277	[11]	0		277	[11]	174	[12]
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		0		535	[11]	0		535	[11]	60	[12]
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss		0		812	[11]	0		812	[11]	234	[12]
Privately issued residential mortgage-backed securities | Alt A loans Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost		38,334		49,522		38,334		49,522		44,245
Available-for-sale Securities, Fair Value		46,903		54,536		46,903		54,536		51,512
Available-for-sale Securities, Gross Unrealized Gain		8,569	[1]	5,461	[2]	8,569	[1]	5,461	[2]	7,485	[3]
Available-for-sale Securities, Gross Unrealized Loss		0	[1]	0	[2]	0	[1]	0	[2]	0	[3]
Available-for-Sale Securities, Other Than Temporary Impairments		0	[4]	(447)	[5]	0	[4]	(447)	[5]	(218)	[6]
Available-for-sale Securities, Debt Maturities, Amortized Cost Basis, Rolling Maturity [Abstract]
Available-for-sale Securities, Debt Maturities, Amortized Cost		38,334		49,522		38,334		49,522		44,245
Available-for-sale Securities, Debt Maturities, Fair Value, Rolling Maturity [Abstract]
Available-for-sale Securities, Debt Maturities, Fair Value		$ 46,903		$ 54,536		$ 46,903		$ 54,536		$ 51,512
Available-for-sale Securities, Continuous Unrealized Loss Position, Qualitative Disclosure [Abstract]
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions		0		5	[11]	0		5	[11]	5	[12]
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		$ 8,513	[11]	$ 0		$ 8,513	[11]	$ 7,931	[12]
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		0		8,291	[11]	0		8,291	[11]	7,410	[12]
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value		0		16,804	[11]	0		16,804	[11]	15,341	[12]
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		241	[11]	0		241	[11]	174	[12]
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		0		206	[11]	0		206	[11]	44	[12]
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss		0		447	[11]	0		447	[11]	218	[12]
Privately issued residential mortgage-backed securities | Jumbo A loans [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost		48,322		65,787		48,322		65,787		56,947
Available-for-sale Securities, Fair Value		56,480		71,777		56,480		71,777		64,023
Available-for-sale Securities, Gross Unrealized Gain		8,158	[1]	6,355	[2]	8,158	[1]	6,355	[2]	7,092	[3]
Available-for-sale Securities, Gross Unrealized Loss		0	[1]	(36)	[2]	0	[1]	(36)	[2]	(16)	[3]
Available-for-Sale Securities, Other Than Temporary Impairments		0	[4]	(329)	[5]	0	[4]	(329)	[5]	0	[6]
Available-for-sale Securities, Debt Maturities, Amortized Cost Basis, Rolling Maturity [Abstract]
Available-for-sale Securities, Debt Maturities, Amortized Cost		48,322		65,787		48,322		65,787		56,947
Available-for-sale Securities, Debt Maturities, Fair Value, Rolling Maturity [Abstract]
Available-for-sale Securities, Debt Maturities, Fair Value		$ 56,480		$ 71,777		$ 56,480		$ 71,777		$ 64,023
Available-for-sale Securities, Continuous Unrealized Loss Position, Qualitative Disclosure [Abstract]
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions		0		9	[11]	0		9	[11]	1	[12]
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		$ 7,076	[11]	$ 0		$ 7,076	[11]	$ 0	[12]
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		0		7,877	[11]	0		7,877	[11]	6,098	[12]
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value		0		14,953	[11]	0		14,953	[11]	6,098	[12]
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		36	[11]	0		36	[11]	0	[12]
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		0		329	[11]	0		329	[11]	16	[12]
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss		0		365	[11]	0		365	[11]	16	[12]
Perpetual Preferred, Equity Securities and Mutual Funds [Member]
Available-for-sale Securities, Debt Maturities, Amortized Cost Basis, Rolling Maturity [Abstract]
Available-for-sale Securities, Debt Maturities, without Single Maturity Date, Amortized Cost Basis		30,134				30,134
Available-for-sale Securities, Debt Maturities, Fair Value, Rolling Maturity [Abstract]
Available-for-sale Securities, Debt Maturities, without Single Maturity Date, Fair Value		$ 35,296				$ 35,296
Available-for-sale Securities, Debt Maturities, Nominal Yield [Abstract]
Available-for-sale Securities, Debt Maturities, Nominal Yield		0.00%				0.00%
Perpetual preferred stock
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost		$ 12,562		15,562		$ 12,562		15,562		15,561
Available-for-sale Securities, Fair Value		16,568		17,931		16,568		17,931		18,474
Available-for-sale Securities, Gross Unrealized Gain		4,006	[1]	2,369	[2]	4,006	[1]	2,369	[2]	2,913	[3]
Available-for-sale Securities, Gross Unrealized Loss		0	[1]	0	[2]	0	[1]	0	[2]	0	[3]
Available-for-Sale Securities, Other Than Temporary Impairments		0	[4]	0	[5]	0	[4]	0	[5]	0	[6]
Available-for-sale Securities, Debt Maturities, Amortized Cost Basis, Rolling Maturity [Abstract]
Available-for-sale Securities, Debt Maturities, Amortized Cost		12,562		15,562		12,562		15,562		15,561
Available-for-sale Securities, Debt Maturities, Fair Value, Rolling Maturity [Abstract]
Available-for-sale Securities, Debt Maturities, Fair Value		$ 16,568		$ 17,931		$ 16,568		$ 17,931		$ 18,474
Available-for-sale Securities, Continuous Unrealized Loss Position, Qualitative Disclosure [Abstract]
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions		0		0		0		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		$ 0		$ 0		$ 0
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		0		0		0		0		0
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value		0		0		0		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		0		0		0
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		0		0		0		0		0
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss		0		0		0		0		0
Equity securities and mutual funds
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost		17,572		17,270		17,572		17,270		17,424
Available-for-sale Securities, Fair Value		18,728		18,814		18,728		18,814		18,357
Available-for-sale Securities, Gross Unrealized Gain		1,219	[1]	1,558	[2]	1,219	[1]	1,558	[2]	1,060	[3]
Available-for-sale Securities, Gross Unrealized Loss		(63)	[1]	(14)	[2]	(63)	[1]	(14)	[2]	(127)	[3]
Available-for-Sale Securities, Other Than Temporary Impairments		0	[4]	0	[5]	0	[4]	0	[5]	0	[6]
Available-for-sale Securities, Debt Maturities, Amortized Cost Basis, Rolling Maturity [Abstract]
Available-for-sale Securities, Debt Maturities, Amortized Cost		17,572		17,270		17,572		17,270		17,424
Available-for-sale Securities, Debt Maturities, Fair Value, Rolling Maturity [Abstract]
Available-for-sale Securities, Debt Maturities, Fair Value		$ 18,728		$ 18,814		$ 18,728		$ 18,814		$ 18,357
Available-for-sale Securities, Continuous Unrealized Loss Position, Qualitative Disclosure [Abstract]
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions		91		30		91		30		104
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		$ 1,668		$ 0		$ 1,668		$ 0		$ 2,127
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		887		889		887		889		817
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value		2,555		889		2,555		889		2,944
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		0		22		0		41
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		41		14		41		14		86
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss		$ 63		$ 14		$ 63		$ 14		$ 127
[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]	Gross unrealized gain/loss recognized in AOCI in the consolidated balance sheet.
[4]	Amounts represent unrealized loss that remains in AOCI after an other-than-temporary credit loss has been recognized in income.
[5]	Amounts represent unrealized loss that remains in AOCI after an other-than-temporary credit loss has been recognized in income.
[6]	Amounts represent unrealized loss that remains in AOCI after an other-than-temporary credit loss has been recognized in income.
[7]	Expected maturities may differ from contractual maturities because borrowers may have the right to call or prepay obligations with or without penalty.
[8]	Calculated on a taxable equivalent basis using a 39 percent effective tax rate.
[9]	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.
[10]	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.
[11]	Includes securities for which an unrealized loss remains in AOCI after an other-than-temporary credit loss has been recognized in income.
[12]	Includes securities for which an unrealized loss remains in AOCI after an other-than-temporary credit loss has been recognized in income.

Securities Fair Value Option Se

Securities Fair Value Option Securities (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016	Jun. 30, 2016
Schedule of Fair Value Option Securities [Line Items]
Fair Value Option Securities, Fair Value	$ 445,169	$ 77,046	$ 263,265
Fair Value Option Securities, Net Unrealized Gain or Loss	1,247	(1,777)	4,433
U.S. Treasury
Schedule of Fair Value Option Securities [Line Items]
Fair Value Option Securities, Fair Value	0	0	25,306
Fair Value Option Securities, Net Unrealized Gain or Loss	0	0	(43)
U.S. government agency residential mortgage-backed securities
Schedule of Fair Value Option Securities [Line Items]
Fair Value Option Securities, Fair Value	445,169	77,046	237,959
Fair Value Option Securities, Net Unrealized Gain or Loss	$ 1,247	$ (1,777)	$ 4,476

Securities Restricted Equity Se

Securities Restricted Equity Securities (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016	Jun. 30, 2016
Restricted Equity Securities [Abstract]
Federal Reserve stock	$ 36,676	$ 36,498	$ 36,283
Federal Home Loan Bank stock	274,113	270,541	283,155
Other	244	201	201
Total	$ 311,033	$ 307,240	$ 319,639

Derivatives, Fair Value of Deri

Derivatives, Fair Value of Derivatives Contracts (Details) - USD ($) $ in Thousands	Jun. 30, 2017		Dec. 31, 2016		Jun. 30, 2016
Derivative Assets, Fair Value, Net [Abstract]
Derviative contracts, net of cash collateral, Assets, Fair value	$ 280,289		$ 689,872		$ 883,673
Derivative Liabilities, Fair Value, Net [Abstract]
Derivative Liabilities, Fair Value, Net of Cash Collateral	285,819		664,531		719,159
Not Designated as Hedging Instrument [Member]
Notional Amount of Derivatives [Abstract]
Derivative Assets, Notional	29,511,796	[1]	22,437,314	[2]	23,037,973	[3]
Derivative Liabilities, Notional	27,125,429	[1]	22,178,359	[2]	21,565,820	[3]
Derivative Assets, Fair Value, Net [Abstract]
Derivative Assets, Gross Fair Value	355,296		789,791		993,485
Derivative Assets, Netting Adjustments	(50,607)		(89,368)		(102,988)
Derivative Assets, Net Fair Value Before Cash Collateral	304,689		700,423		890,497
Derivative Assets, Cash Collateral	(24,400)		(10,551)		(6,824)
Derviative contracts, net of cash collateral, Assets, Fair value	280,289		689,872		883,673
Derivative Liabilities, Fair Value, Net [Abstract]
Derivative Liabilities, Gross Fair Value	357,521		801,809		974,975
Derivative Liabilities, Netting Adjustments	(50,607)		(89,368)		(102,988)
Derivative Liabilities, Net Fair Value Before Cash Collateral	306,914		712,441		871,987
Derivative Liabilities, Cash Collateral	(21,095)		(47,910)		(152,828)
Derivative Liabilities, Fair Value, Net of Cash Collateral	285,819		664,531		719,159
Not Designated as Hedging Instrument [Member] | To-be-announced residential mortgage-backed securities
Notional Amount of Derivatives [Abstract]
Derivative Assets, Notional	16,174,687	[1]	16,949,152	[2]	18,774,134	[3]
Derivative Liabilities, Notional	16,174,687	[1]	16,637,532	[2]	18,662,334	[3]
Derivative Assets, Fair Value, Net [Abstract]
Derivative Assets, Gross Fair Value	57,948		180,695		183,118
Derivative Assets, Netting Adjustments	(29,034)		(60,555)		(67,383)
Derivative Assets, Net Fair Value Before Cash Collateral	28,914		120,140		115,735
Derivative Assets, Cash Collateral	0		0		0
Derviative contracts, net of cash collateral, Assets, Fair value	28,914		120,140		115,735
Derivative Liabilities, Fair Value, Net [Abstract]
Derivative Liabilities, Gross Fair Value	53,829		176,928		179,443
Derivative Liabilities, Netting Adjustments	(29,034)		(60,555)		(67,383)
Derivative Liabilities, Net Fair Value Before Cash Collateral	24,795		116,373		112,060
Derivative Liabilities, Cash Collateral	0		0		(103,724)
Derivative Liabilities, Fair Value, Net of Cash Collateral	24,795		116,373		8,336
Not Designated as Hedging Instrument [Member] | Interest rate swaps
Notional Amount of Derivatives [Abstract]
Derivative Assets, Notional	1,450,193	[1]	1,403,408	[2]	1,299,985	[3]
Derivative Liabilities, Notional	1,450,193	[1]	1,403,408	[2]	1,299,985	[3]
Derivative Assets, Fair Value, Net [Abstract]
Derivative Assets, Gross Fair Value	29,932		34,442		54,978
Derivative Assets, Netting Adjustments	0		0		0
Derivative Assets, Net Fair Value Before Cash Collateral	29,932		34,442		54,978
Derivative Assets, Cash Collateral	(2,206)		(4,567)		(1,100)
Derviative contracts, net of cash collateral, Assets, Fair value	27,726		29,875		53,878
Derivative Liabilities, Fair Value, Net [Abstract]
Derivative Liabilities, Gross Fair Value	29,982		34,442		55,404
Derivative Liabilities, Netting Adjustments	0		0		0
Derivative Liabilities, Net Fair Value Before Cash Collateral	29,982		34,442		55,404
Derivative Liabilities, Cash Collateral	(15,396)		(11,977)		(32,597)
Derivative Liabilities, Fair Value, Net of Cash Collateral	14,586		22,465		22,807
Not Designated as Hedging Instrument [Member] | Energy contracts
Notional Amount of Derivatives [Abstract]
Derivative Assets, Notional	891,480	[1]	835,566	[2]	757,669	[3]
Derivative Liabilities, Notional	874,625	[1]	820,365	[2]	734,538	[3]
Derivative Assets, Fair Value, Net [Abstract]
Derivative Assets, Gross Fair Value	56,824		64,140		59,103
Derivative Assets, Netting Adjustments	(20,546)		(28,298)		(33,996)
Derivative Assets, Net Fair Value Before Cash Collateral	36,278		35,842		25,107
Derivative Assets, Cash Collateral	(21,267)		(71)		(155)
Derviative contracts, net of cash collateral, Assets, Fair value	15,011		35,771		24,952
Derivative Liabilities, Fair Value, Net [Abstract]
Derivative Liabilities, Gross Fair Value	53,895		64,306		58,033
Derivative Liabilities, Netting Adjustments	(20,546)		(28,298)		(33,996)
Derivative Liabilities, Net Fair Value Before Cash Collateral	33,349		36,008		24,037
Derivative Liabilities, Cash Collateral	0		(31,534)		(11,784)
Derivative Liabilities, Fair Value, Net of Cash Collateral	33,349		4,474		12,253
Not Designated as Hedging Instrument [Member] | Agricultural contracts
Notional Amount of Derivatives [Abstract]
Derivative Assets, Notional	45,250	[1]	53,209	[2]	50,848	[3]
Derivative Liabilities, Notional	45,262	[1]	53,216	[2]	50,843	[3]
Derivative Assets, Fair Value, Net [Abstract]
Derivative Assets, Gross Fair Value	3,541		1,382		2,488
Derivative Assets, Netting Adjustments	(1,027)		(515)		(1,609)
Derivative Assets, Net Fair Value Before Cash Collateral	2,514		867		879
Derivative Assets, Cash Collateral	0		0		(37)
Derviative contracts, net of cash collateral, Assets, Fair value	2,514		867		842
Derivative Liabilities, Fair Value, Net [Abstract]
Derivative Liabilities, Gross Fair Value	3,538		1,365		2,476
Derivative Liabilities, Netting Adjustments	(1,027)		(515)		(1,609)
Derivative Liabilities, Net Fair Value Before Cash Collateral	2,511		850		867
Derivative Liabilities, Cash Collateral	(2,511)		(769)		0
Derivative Liabilities, Fair Value, Net of Cash Collateral	0		81		867
Not Designated as Hedging Instrument [Member] | Foreign exchange contracts
Notional Amount of Derivatives [Abstract]
Derivative Assets, Notional	169,529	[1]	580,886	[2]	701,436	[3]
Derivative Liabilities, Notional	169,553	[1]	580,712	[2]	701,219	[3]
Derivative Assets, Fair Value, Net [Abstract]
Derivative Assets, Gross Fair Value	162,429		494,349		675,804
Derivative Assets, Netting Adjustments	0		0		0
Derivative Assets, Net Fair Value Before Cash Collateral	162,429		494,349		675,804
Derivative Assets, Cash Collateral	(7)		(5,183)		(5,054)
Derviative contracts, net of cash collateral, Assets, Fair value	162,422		489,166		670,750
Derivative Liabilities, Fair Value, Net [Abstract]
Derivative Liabilities, Gross Fair Value	162,276		494,695		675,383
Derivative Liabilities, Netting Adjustments	0		0		0
Derivative Liabilities, Net Fair Value Before Cash Collateral	162,276		494,695		675,383
Derivative Liabilities, Cash Collateral	(3,188)		(3,630)		(4,723)
Derivative Liabilities, Fair Value, Net of Cash Collateral	159,088		491,065		670,660
Not Designated as Hedging Instrument [Member] | Equity option contracts
Notional Amount of Derivatives [Abstract]
Derivative Assets, Notional	100,159	[1]	100,924	[2]	116,901	[3]
Derivative Liabilities, Notional	100,159	[1]	100,924	[2]	116,901	[3]
Derivative Assets, Fair Value, Net [Abstract]
Derivative Assets, Gross Fair Value	4,437		4,357		4,236
Derivative Assets, Netting Adjustments	0		0		0
Derivative Assets, Net Fair Value Before Cash Collateral	4,437		4,357		4,236
Derivative Assets, Cash Collateral	(920)		(730)		(478)
Derviative contracts, net of cash collateral, Assets, Fair value	3,517		3,627		3,758
Derivative Liabilities, Fair Value, Net [Abstract]
Derivative Liabilities, Gross Fair Value	4,437		4,357		4,236
Derivative Liabilities, Netting Adjustments	0		0		0
Derivative Liabilities, Net Fair Value Before Cash Collateral	4,437		4,357		4,236
Derivative Liabilities, Cash Collateral	0		0		0
Derivative Liabilities, Fair Value, Net of Cash Collateral	4,437		4,357		4,236
Not Designated as Hedging Instrument [Member] | Total customer risk management programs
Notional Amount of Derivatives [Abstract]
Derivative Assets, Notional	18,831,298	[1]	19,923,145	[2]	21,700,973	[3]
Derivative Liabilities, Notional	18,814,479	[1]	19,596,157	[2]	21,565,820	[3]
Derivative Assets, Fair Value, Net [Abstract]
Derivative Assets, Gross Fair Value	315,111		779,365		979,727
Derivative Assets, Netting Adjustments	(50,607)		(89,368)		(102,988)
Derivative Assets, Net Fair Value Before Cash Collateral	264,504		689,997		876,739
Derivative Assets, Cash Collateral	(24,400)		(10,551)		(6,824)
Derviative contracts, net of cash collateral, Assets, Fair value	240,104		679,446		869,915
Derivative Liabilities, Fair Value, Net [Abstract]
Derivative Liabilities, Gross Fair Value	307,957		776,093		974,975
Derivative Liabilities, Netting Adjustments	(50,607)		(89,368)		(102,988)
Derivative Liabilities, Net Fair Value Before Cash Collateral	257,350		686,725		871,987
Derivative Liabilities, Cash Collateral	(21,095)		(47,910)		(152,828)
Derivative Liabilities, Fair Value, Net of Cash Collateral	236,255		638,815		719,159
Not Designated as Hedging Instrument [Member] | Internal risk management programs
Notional Amount of Derivatives [Abstract]
Derivative Assets, Notional	10,680,498	[1]	2,514,169	[2]	1,337,000	[3]
Derivative Liabilities, Notional	8,310,950	[1]	2,582,202	[2]	0	[3]
Derivative Assets, Fair Value, Net [Abstract]
Derivative Assets, Gross Fair Value	40,185		10,426		13,758
Derivative Assets, Netting Adjustments	0		0		0
Derivative Assets, Net Fair Value Before Cash Collateral	40,185		10,426		13,758
Derivative Assets, Cash Collateral	0		0		0
Derviative contracts, net of cash collateral, Assets, Fair value	40,185		10,426		13,758
Derivative Liabilities, Fair Value, Net [Abstract]
Derivative Liabilities, Gross Fair Value	49,564		25,716		0
Derivative Liabilities, Netting Adjustments	0		0		0
Derivative Liabilities, Net Fair Value Before Cash Collateral	49,564		25,716		0
Derivative Liabilities, Cash Collateral	0		0		0
Derivative Liabilities, Fair Value, Net of Cash Collateral	$ 49,564		$ 25,716		$ 0
[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.
[3]	Notional amounts for commodity contracts are converted into dollar-equivalent amounts based on dollar prices at the inception of the contract.

Derivatives, Derivatives Instru

Derivatives, Derivatives Instruments Gain (Loss) in Income Statement (Details) - Not Designated as Hedging Instrument [Member] - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Derivative Instruments, Gain (Loss) Recognized in Income, Net [Abstract]
Brokergage and Trading Revenue	$ 18,122	$ 13,491	$ 29,293	$ 22,359
Gain (Loss) on Derivatives, Net	3,241	10,766	2,791	17,904
To-be-announced residential mortgage-backed securities
Derivative Instruments, Gain (Loss) Recognized in Income, Net [Abstract]
Brokergage and Trading Revenue	9,205	9,862	17,232	17,302
Gain (Loss) on Derivatives, Net	0	0	0	0
Interest rate swaps
Derivative Instruments, Gain (Loss) Recognized in Income, Net [Abstract]
Brokergage and Trading Revenue	665	723	1,124	1,048
Gain (Loss) on Derivatives, Net	0	0	0	0
Energy contracts
Derivative Instruments, Gain (Loss) Recognized in Income, Net [Abstract]
Brokergage and Trading Revenue	1,666	2,749	4,539	3,445
Gain (Loss) on Derivatives, Net	0	0	0	0
Agricultural contracts
Derivative Instruments, Gain (Loss) Recognized in Income, Net [Abstract]
Brokergage and Trading Revenue	11	32	20	61
Gain (Loss) on Derivatives, Net	0	0	0	0
Foreign exchange contracts
Derivative Instruments, Gain (Loss) Recognized in Income, Net [Abstract]
Brokergage and Trading Revenue	90	134	360	512
Gain (Loss) on Derivatives, Net	0	0	0	0
Equity option contracts
Derivative Instruments, Gain (Loss) Recognized in Income, Net [Abstract]
Brokergage and Trading Revenue	0	0	0	0
Gain (Loss) on Derivatives, Net	0	0	0	0
Total customer risk management programs
Derivative Instruments, Gain (Loss) Recognized in Income, Net [Abstract]
Brokergage and Trading Revenue	11,637	13,500	23,275	22,368
Gain (Loss) on Derivatives, Net	0	0	0	0
Internal risk management programs
Derivative Instruments, Gain (Loss) Recognized in Income, Net [Abstract]
Brokergage and Trading Revenue	6,485	(9)	6,018	(9)
Gain (Loss) on Derivatives, Net	$ 3,241	$ 10,766	$ 2,791	$ 17,904

Loans and Allowance for Credit

Loans and Allowance for Credit Losses, Loans by Portfolio Type (Details) - USD ($) $ in Thousands		6 Months Ended
		Jun. 30, 2017	Dec. 31, 2016	Jun. 30, 2016
Loan receivables disclosure [Abstract]
Loans, fixed rate of interest		$ 4,540,923	$ 4,753,600	$ 4,302,800
Loans, variable rate of interest		12,397,283	12,005,076	11,856,765
Loans, non-accrual		245,439	230,984	247,184
Total		17,183,645	16,989,660	16,406,749
Accruing loans past due (90 days)	[1]	1,414	5	2,899
Credit Commitments [Abstract]
Outstanding commitments to extend credit		9,600,000
Outstanding standby letters of credit		615,000
Outstanding commercial letters of credit		3,200
Texas [Member] | Geographic Concentration Risk [Member]
Loan receivables disclosure [Abstract]
Total		$ 5,700,000
Loans receivable, other information [Abstract]
Percentage of loan portfolio attributed to Texas (in hundredths)		33.00%
Oklahoma [Member] | Geographic Concentration Risk [Member]
Loan receivables disclosure [Abstract]
Total		$ 3,400,000
Loans receivable, other information [Abstract]
Percentage of loan portfolio attributed to Oklahoma (in hundredths)		20.00%
Commercial
Loan receivables disclosure [Abstract]
Loans, fixed rate of interest		$ 2,198,066	2,327,085	1,994,415
Loans, variable rate of interest		8,242,732	7,884,786	8,180,033
Loans, non-accrual		197,157	178,953	181,989
Total		10,637,955	10,390,824	10,356,437
Commercial | Texas [Member] | Geographic Concentration Risk [Member]
Loan receivables disclosure [Abstract]
Total		$ 3,600,000
Loans receivable, other information [Abstract]
Percentage of loan portfolio attributed to Texas (in hundredths)		33.00%
Commercial | Oklahoma [Member] | Geographic Concentration Risk [Member]
Loan receivables disclosure [Abstract]
Total		$ 2,100,000
Loans receivable, other information [Abstract]
Percentage of loan portfolio attributed to Oklahoma (in hundredths)		19.00%
Commercial | Energy [Member]
Loan receivables disclosure [Abstract]
Total		$ 2,847,240	2,497,868	2,818,656
Commercial | Energy [Member] | Credit Concentration Risk [Member]
Loan receivables disclosure [Abstract]
Total		$ 2,800,000
Loans receivable, other information [Abstract]
Percentage of loan class to total loans		17.00%
Commercial | Energy Producers [Member] | Credit Concentration Risk [Member]
Loan receivables disclosure [Abstract]
Total		$ 2,400,000
Loans receivable, other information [Abstract]
Percentage of committed energy production loans secured by oil		58.00%
Percentage of committed energy production loans secured by natural gas		42.00%
Commercial | Services [Member]
Loan receivables disclosure [Abstract]
Total		$ 2,958,827	3,108,990	2,830,864
Commercial | Services [Member] | Credit Concentration Risk [Member]
Loan receivables disclosure [Abstract]
Total		$ 3,000,000
Loans receivable, other information [Abstract]
Percentage of loan class to total loans		17.00%
Amount of loans with individual balances less than $10 million		$ 1,500,000
Maximum loan amount for certain individual loans in category		10,000
Commercial | Healthcare [Member]
Loan receivables disclosure [Abstract]
Total		2,221,518	2,201,916	2,051,146
Commercial | Healthcare [Member] | Credit Concentration Risk [Member]
Loan receivables disclosure [Abstract]
Total		$ 2,200,000
Loans receivable, other information [Abstract]
Percentage of loan class to total loans		13.00%
Commercial real estate
Loan receivables disclosure [Abstract]
Loans, fixed rate of interest		$ 594,542	624,187	612,822
Loans, variable rate of interest		3,090,275	3,179,338	2,961,364
Loans, non-accrual		3,775	5,521	7,780
Total		$ 3,688,592	3,809,046	3,581,966
Commercial real estate | Texas [Member] | Geographic Concentration Risk [Member]
Loans receivable, other information [Abstract]
Percentage of loan portfolio secured by property in Texas (in hundredths)		32.00%
Commercial real estate | Oklahoma [Member] | Geographic Concentration Risk [Member]
Loans receivable, other information [Abstract]
Percentage of loan portfolio secured by property in Oklahoma (in hundredths)		12.00%
Residential mortgage
Loan receivables disclosure [Abstract]
Loans, fixed rate of interest		$ 1,597,587	1,647,357	1,586,116
Loans, variable rate of interest		297,376	256,255	237,746
Loans, non-accrual		44,235	46,220	57,061
Total		1,939,198	1,949,832	1,880,923
Residential mortgage | Permanent mortgage [Member]
Loan receivables disclosure [Abstract]
Total		$ 989,040	1,006,820	969,007
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 | Permanent mortgages guaranteed by US government agencies [Member]
Loan receivables disclosure [Abstract]
Total		$ 191,729	199,387	192,732
Loans receivable, other information [Abstract]
Amount of loans guaranteed by US government and previously sold into GNMA mortgage pools		192,000
Residential mortgage | Home equity [Member]
Loan receivables disclosure [Abstract]
Total		$ 758,429	743,625	719,184
Loans receivable, other information [Abstract]
Percentage of home equity portfolio comprised of first lien loans		65.00%
Percentage of home equity portfolio comprised of junior lien loans		35.00%
Percentage of junior lien home equity loans that are amortizing term loans		49.00%
Percentage of junior lien home equity loans that are revolving lines of credit		51.00%
Home equity loans, description		Home equity loans generally require a minimum FICO score of 700 and a maximum DTI of 40 percent.
Home equity loans, maximum		$ 400
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
Loan receivables disclosure [Abstract]
Loans, fixed rate of interest		$ 150,728	154,971	109,447
Loans, variable rate of interest		766,900	684,697	477,622
Loans, non-accrual		272	290	354
Total		$ 917,900	$ 839,958	$ 587,423
[1]	Excludes residential mortgage loans guaranteed by agencies of the U.S. government

Loans and Allowances for Cred42

Loans and Allowances for Credit Losses, Activity in Allowance for Credit Losses (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Dec. 31, 2016	Jun. 30, 2016
Allowance for loan losses [Roll Forward]
Beginning balance	$ 248,710	$ 233,156	$ 246,159	$ 225,524
Provision for loan losses	3,009	17,562	4,813	47,666
Loans charged off	(2,872)	(8,845)	(5,025)	(32,836)
Recoveries	1,214	1,386	4,114	2,905
Ending balance	250,061	243,259	250,061	243,259
Allowance for off-balance sheet credit losses [Roll Forward]
Beginning balance	9,440	6,607	11,244	1,711
Provision for off-balance sheet credit losses	(3,009)	2,438	(4,813)	7,334
Ending balance	6,431	9,045	6,431	9,045
Total provision for credit losses	0	20,000	0	55,000
Recorded investment [Abstract]
Collectively measured for impairment, recorded investment					$ 16,938,206	$ 16,758,676	$ 16,159,565
Individually measured for impairment, recorded investment					245,439	230,984	247,184
Total					17,183,645	16,989,660	16,406,749
Related allowance [Abstract]
Collectively measured for impairment, related allowance					212,994	217,116	212,265
Individually measured for impairment, related allowance					9,693	843	4,310
Total	248,710	233,156	246,159	225,524	250,061	246,159	243,259
Commercial
Allowance for loan losses [Roll Forward]
Beginning balance	137,616	139,793	140,213	130,334
Provision for loan losses	1,546	12,478	(1,809)	43,575
Loans charged off	(1,703)	(7,355)	(2,127)	(29,481)
Recoveries	283	223	1,465	711
Ending balance	137,742	145,139	137,742	145,139
Allowance for off-balance sheet credit losses [Roll Forward]
Beginning balance	9,288	6,319	11,063	1,506
Provision for off-balance sheet credit losses	(2,987)	2,433	(4,762)	7,246
Ending balance	6,301	8,752	6,301	8,752
Total provision for credit losses	(1,441)	14,911	(6,571)	50,821
Recorded investment [Abstract]
Collectively measured for impairment, recorded investment					10,440,798	10,211,871	10,174,448
Individually measured for impairment, recorded investment					197,157	178,953	181,989
Total					10,637,955	10,390,824	10,356,437
Related allowance [Abstract]
Collectively measured for impairment, related allowance					128,049	139,416	140,911
Individually measured for impairment, related allowance					9,693	797	4,228
Total	137,616	139,793	140,213	130,334	137,742	140,213	145,139
Commercial real estate
Allowance for loan losses [Roll Forward]
Beginning balance	58,343	44,453	50,749	41,391
Provision for loan losses	105	2,010	6,964	4,987
Loans charged off	(76)	0	(76)	0
Recoveries	208	282	943	367
Ending balance	58,580	46,745	58,580	46,745
Allowance for off-balance sheet credit losses [Roll Forward]
Beginning balance	106	228	123	153
Provision for off-balance sheet credit losses	(22)	(25)	(39)	50
Ending balance	84	203	84	203
Total provision for credit losses	83	1,985	6,925	5,037
Recorded investment [Abstract]
Collectively measured for impairment, recorded investment					3,684,817	3,803,525	3,574,186
Individually measured for impairment, recorded investment					3,775	5,521	7,780
Total					3,688,592	3,809,046	3,581,966
Related allowance [Abstract]
Collectively measured for impairment, related allowance					58,580	50,749	46,727
Individually measured for impairment, related allowance					0	0	18
Total	58,343	44,453	50,749	41,391	58,580	50,749	46,745
Residential mortgage
Allowance for loan losses [Roll Forward]
Beginning balance	18,177	18,467	18,224	19,509
Provision for loan losses	(47)	368	(86)	(363)
Loans charged off	(40)	(345)	(276)	(819)
Recoveries	169	200	397	363
Ending balance	18,259	18,690	18,259	18,690
Allowance for off-balance sheet credit losses [Roll Forward]
Beginning balance	40	58	50	30
Provision for off-balance sheet credit losses	(2)	4	(12)	32
Ending balance	38	62	38	62
Total provision for credit losses	(49)	372	(98)	(331)
Recorded investment [Abstract]
Collectively measured for impairment, recorded investment					1,894,963	1,903,612	1,823,862
Individually measured for impairment, recorded investment					44,235	46,220	57,061
Total					1,939,198	1,949,832	1,880,923
Related allowance [Abstract]
Collectively measured for impairment, related allowance					18,259	18,178	18,626
Individually measured for impairment, related allowance					0	46	64
Total	18,177	18,467	18,224	19,509	18,259	18,224	18,690
Personal
Allowance for loan losses [Roll Forward]
Beginning balance	7,247	5,022	8,773	4,164
Provision for loan losses	1,358	1,443	570	2,909
Loans charged off	(1,053)	(1,145)	(2,546)	(2,536)
Recoveries	554	681	1,309	1,464
Ending balance	8,106	6,001	8,106	6,001
Allowance for off-balance sheet credit losses [Roll Forward]
Beginning balance	6	2	8	22
Provision for off-balance sheet credit losses	2	26	0	6
Ending balance	8	28	8	28
Total provision for credit losses	1,360	1,469	570	2,915
Recorded investment [Abstract]
Collectively measured for impairment, recorded investment					917,628	839,668	587,069
Individually measured for impairment, recorded investment					272	290	354
Total					917,900	839,958	587,423
Related allowance [Abstract]
Collectively measured for impairment, related allowance					8,106	8,773	6,001
Individually measured for impairment, related allowance					0	0	0
Total	7,247	5,022	8,773	4,164	8,106	8,773	6,001
Specific Allowance [Member]
Allowance for loan losses [Roll Forward]
Beginning balance			217,959
Ending balance	222,687	216,575	222,687	216,575
Recorded investment [Abstract]
Collectively measured for impairment, recorded investment					16,938,206	16,758,676	16,159,565
Individually measured for impairment, recorded investment					245,439	230,984	247,184
Total					17,183,645	16,989,660	16,406,749
Related allowance [Abstract]
Collectively measured for impairment, related allowance					212,994	217,116	212,265
Individually measured for impairment, related allowance					9,693	843	4,310
Total	222,687	216,575	217,959	216,575	222,687	217,959	216,575
Nonspecific Allowance [Member]
Allowance for loan losses [Roll Forward]
Beginning balance	27,327	25,421	28,200	30,126
Provision for loan losses	47	1,263	(826)	(3,442)
Loans charged off	0	0	0	0
Recoveries	0	0	0	0
Ending balance	27,374	26,684	27,374	26,684
Allowance for off-balance sheet credit losses [Roll Forward]
Beginning balance	0	0	0	0
Provision for off-balance sheet credit losses	0	0	0	0
Ending balance	0	0	0	0
Total provision for credit losses	47	1,263	(826)	(3,442)
Recorded investment [Abstract]
Collectively measured for impairment, recorded investment					0	0	0
Individually measured for impairment, recorded investment					0	0	0
Total					0	0	0
Related allowance [Abstract]
Collectively measured for impairment, related allowance					0	0	0
Individually measured for impairment, related allowance					0	0	0
Total	$ 27,327	$ 25,421	$ 28,200	$ 30,126	$ 27,374	$ 28,200	$ 26,684

Loans and Allowances for Cred43

Loans and Allowances for Credit Losses, Credit Quality Indicators (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	$ 15,341,394		$ 15,158,076	$ 14,616,427
Non-Graded, Recorded Investment	1,842,251		1,831,584	1,790,322
Total	17,183,645		16,989,660	16,406,749
Related Allowance [Abstract]
Internally Risk Graded, Allowance	204,117		197,970	197,581
Non-Graded, Allowance	18,570		19,989	18,994
Total	250,061	$ 248,710	246,159	243,259	$ 233,156	$ 225,524
Commercial
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	10,612,477		10,360,725	10,331,701
Non-Graded, Recorded Investment	25,478		30,099	24,736
Total	10,637,955		10,390,824	10,356,437
Related Allowance [Abstract]
Internally Risk Graded, Allowance	136,819		139,293	144,217
Non-Graded, Allowance	923		920	922
Total	137,742	137,616	140,213	145,139	139,793	130,334
Commercial | Energy [Member]
Recorded Investment [Abstract]
Total	2,847,240		2,497,868	2,818,656
Commercial | Services [Member]
Recorded Investment [Abstract]
Total	2,958,827		3,108,990	2,830,864
Commercial | Wholesale/retail [Member]
Recorded Investment [Abstract]
Total	1,543,695		1,576,818	1,532,957
Commercial | Manufacturing [Member]
Recorded Investment [Abstract]
Total	546,137		514,975	595,403
Commercial | Healthcare [Member]
Recorded Investment [Abstract]
Total	2,221,518		2,201,916	2,051,146
Commercial | Other commercial and industrial [Member]
Recorded Investment [Abstract]
Total	520,538		490,257	527,411
Commercial real estate
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	3,688,592		3,809,046	3,581,966
Non-Graded, Recorded Investment	0		0	0
Total	3,688,592		3,809,046	3,581,966
Related Allowance [Abstract]
Internally Risk Graded, Allowance	58,580		50,749	46,745
Non-Graded, Allowance	0		0	0
Total	58,580	58,343	50,749	46,745	44,453	41,391
Commercial real estate | Residential construction and land development [Member]
Recorded Investment [Abstract]
Total	141,592		135,533	157,576
Commercial real estate | Retail [Member]
Recorded Investment [Abstract]
Total	722,805		761,888	795,419
Commercial real estate | Office [Member]
Recorded Investment [Abstract]
Total	862,973		798,888	769,112
Commercial real estate | Multifamily [Member]
Recorded Investment [Abstract]
Total	952,380		903,272	787,200
Commercial real estate | Industrial [Member]
Recorded Investment [Abstract]
Total	693,635		871,749	645,586
Commercial real estate | Other commercial real estate [Member]
Recorded Investment [Abstract]
Total	315,207		337,716	427,073
Residential mortgage
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	216,007		243,703	202,520
Non-Graded, Recorded Investment	1,723,191		1,706,129	1,678,403
Total	1,939,198		1,949,832	1,880,923
Related Allowance [Abstract]
Internally Risk Graded, Allowance	2,976		2,893	2,995
Non-Graded, Allowance	15,283		15,331	15,695
Total	18,259	18,177	18,224	18,690	18,467	19,509
Residential mortgage | Permanent mortgage [Member]
Recorded Investment [Abstract]
Total	989,040		1,006,820	969,007
Residential mortgage | Permanent mortgages guaranteed by US government agencies [Member]
Recorded Investment [Abstract]
Total	191,729		199,387	192,732
Residential mortgage | Home equity [Member]
Recorded Investment [Abstract]
Total	758,429		743,625	719,184
Personal
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	824,318		744,602	500,240
Non-Graded, Recorded Investment	93,582		95,356	87,183
Total	917,900		839,958	587,423
Related Allowance [Abstract]
Internally Risk Graded, Allowance	5,742		5,035	3,624
Non-Graded, Allowance	2,364		3,738	2,377
Total	8,106	7,247	8,773	6,001	5,022	4,164
Specific Allowance [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	15,341,394		15,158,076	14,616,427
Non-Graded, Recorded Investment	1,842,251		1,831,584	1,790,322
Total	17,183,645		16,989,660	16,406,749
Related Allowance [Abstract]
Internally Risk Graded, Allowance	204,117		197,970	197,581
Non-Graded, Allowance	18,570		19,989	18,994
Total	222,687		217,959	216,575
Nonspecific Allowance [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	0		0	0
Non-Graded, Recorded Investment	0		0	0
Total	0		0	0
Related Allowance [Abstract]
Internally Risk Graded, Allowance	0		0	0
Non-Graded, Allowance	0		0	0
Total	27,374	$ 27,327	28,200	26,684	$ 25,421	$ 30,126
Performing [Member]
Recorded Investment [Abstract]
Non-Graded, Recorded Investment	1,799,001		1,786,530	1,735,915
Performing [Member] | Commercial
Recorded Investment [Abstract]
Non-Graded, Recorded Investment	25,374		30,041	24,673
Performing [Member] | Commercial | Energy [Member]
Recorded Investment [Abstract]
Non-Graded, Recorded Investment	0		0	0
Performing [Member] | Commercial | Services [Member]
Recorded Investment [Abstract]
Non-Graded, Recorded Investment	0		0	0
Performing [Member] | Commercial | Wholesale/retail [Member]
Recorded Investment [Abstract]
Non-Graded, Recorded Investment	0		0	0
Performing [Member] | Commercial | Manufacturing [Member]
Recorded Investment [Abstract]
Non-Graded, Recorded Investment	0		0	0
Performing [Member] | Commercial | Healthcare [Member]
Recorded Investment [Abstract]
Non-Graded, Recorded Investment	0		0	0
Performing [Member] | Commercial | Other commercial and industrial [Member]
Recorded Investment [Abstract]
Non-Graded, Recorded Investment	25,374		30,041	24,673
Performing [Member] | Commercial real estate
Recorded Investment [Abstract]
Non-Graded, Recorded Investment	0		0	0
Performing [Member] | Commercial real estate | Residential construction and land development [Member]
Recorded Investment [Abstract]
Non-Graded, Recorded Investment	0		0	0
Performing [Member] | Commercial real estate | Retail [Member]
Recorded Investment [Abstract]
Non-Graded, Recorded Investment	0		0	0
Performing [Member] | Commercial real estate | Office [Member]
Recorded Investment [Abstract]
Non-Graded, Recorded Investment	0		0	0
Performing [Member] | Commercial real estate | Multifamily [Member]
Recorded Investment [Abstract]
Non-Graded, Recorded Investment	0		0	0
Performing [Member] | Commercial real estate | Industrial [Member]
Recorded Investment [Abstract]
Non-Graded, Recorded Investment	0		0	0
Performing [Member] | Commercial real estate | Other commercial real estate [Member]
Recorded Investment [Abstract]
Non-Graded, Recorded Investment	0		0	0
Performing [Member] | Residential mortgage
Recorded Investment [Abstract]
Non-Graded, Recorded Investment	1,680,229		1,661,326	1,624,297
Performing [Member] | Residential mortgage | Permanent mortgage [Member]
Recorded Investment [Abstract]
Non-Graded, Recorded Investment	750,891		741,679	742,214
Performing [Member] | Residential mortgage | Permanent mortgages guaranteed by US government agencies [Member]
Recorded Investment [Abstract]
Non-Graded, Recorded Investment	183,000		188,000	173,000
Performing [Member] | Residential mortgage | Home equity [Member]
Recorded Investment [Abstract]
Non-Graded, Recorded Investment	746,661		732,106	709,092
Performing [Member] | Personal
Recorded Investment [Abstract]
Non-Graded, Recorded Investment	93,398		95,163	86,945
Performing [Member] | Pass [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	14,613,315		14,343,507	13,614,112
Performing [Member] | Pass [Member] | Commercial
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	9,902,434		9,567,816	9,363,072
Performing [Member] | Pass [Member] | Commercial | Energy [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	2,376,368		1,937,790	2,031,955
Performing [Member] | Pass [Member] | Commercial | Services [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	2,921,510		3,052,002	2,805,307
Performing [Member] | Pass [Member] | Commercial | Wholesale/retail [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	1,507,063		1,535,463	1,478,966
Performing [Member] | Pass [Member] | Commercial | Manufacturing [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	513,442		468,314	556,741
Performing [Member] | Pass [Member] | Commercial | Healthcare [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	2,130,339		2,140,458	2,011,934
Performing [Member] | Pass [Member] | Commercial | Other commercial and industrial [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	453,712		433,789	478,169
Performing [Member] | Pass [Member] | Commercial real estate
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	3,675,014		3,793,471	3,559,544
Performing [Member] | Pass [Member] | Commercial real estate | Residential construction and land development [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	138,790		131,630	152,343
Performing [Member] | Pass [Member] | Commercial real estate | Retail [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	720,730		756,418	787,779
Performing [Member] | Pass [Member] | Commercial real estate | Office [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	859,722		798,462	767,296
Performing [Member] | Pass [Member] | Commercial real estate | Multifamily [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	947,950		898,800	781,058
Performing [Member] | Pass [Member] | Commercial real estate | Industrial [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	693,635		871,673	645,510
Performing [Member] | Pass [Member] | Commercial real estate | Other commercial real estate [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	314,187		336,488	425,558
Performing [Member] | Pass [Member] | Residential mortgage
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	212,563		238,769	194,962
Performing [Member] | Pass [Member] | Residential mortgage | Permanent mortgage [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	212,563		238,769	194,962
Performing [Member] | Pass [Member] | Residential mortgage | Permanent mortgages guaranteed by US government agencies [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	0		0	0
Performing [Member] | Pass [Member] | Residential mortgage | Home equity [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	0		0	0
Performing [Member] | Pass [Member] | Personal
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	823,304		743,451	496,534
Performing [Member] | Other Loans Especially Mentioned [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	198,575		229,673	308,674
Performing [Member] | Other Loans Especially Mentioned [Member] | Commercial
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	192,204		223,742	300,609
Performing [Member] | Other Loans Especially Mentioned [Member] | Commercial | Energy [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	120,473		119,583	197,531
Performing [Member] | Other Loans Especially Mentioned [Member] | Commercial | Services [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	12,452		10,960	6,253
Performing [Member] | Other Loans Especially Mentioned [Member] | Commercial | Wholesale/retail [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	16,224		16,886	24,595
Performing [Member] | Other Loans Especially Mentioned [Member] | Commercial | Manufacturing [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	6,540		26,532	18,757
Performing [Member] | Other Loans Especially Mentioned [Member] | Commercial | Healthcare [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	33,554		44,472	29,420
Performing [Member] | Other Loans Especially Mentioned [Member] | Commercial | Other commercial and industrial [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	2,961		5,309	24,053
Performing [Member] | Other Loans Especially Mentioned [Member] | Commercial real estate
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	4,629		4,745	6,868
Performing [Member] | Other Loans Especially Mentioned [Member] | Commercial real estate | Residential construction and land development [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	0		0	0
Performing [Member] | Other Loans Especially Mentioned [Member] | Commercial real estate | Retail [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	1,774		4,745	5,962
Performing [Member] | Other Loans Especially Mentioned [Member] | Commercial real estate | Office [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	2,855		0	906
Performing [Member] | Other Loans Especially Mentioned [Member] | Commercial real estate | Multifamily [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	0		0	0
Performing [Member] | Other Loans Especially Mentioned [Member] | Commercial real estate | Industrial [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	0		0	0
Performing [Member] | Other Loans Especially Mentioned [Member] | Commercial real estate | Other commercial real estate [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	0		0	0
Performing [Member] | Other Loans Especially Mentioned [Member] | Residential mortgage
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	1,693		1,186	1,197
Performing [Member] | Other Loans Especially Mentioned [Member] | Residential mortgage | Permanent mortgage [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	1,693		1,186	1,197
Performing [Member] | Other Loans Especially Mentioned [Member] | Residential mortgage | Permanent mortgages guaranteed by US government agencies [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	0		0	0
Performing [Member] | Other Loans Especially Mentioned [Member] | Residential mortgage | Home equity [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	0		0	0
Performing [Member] | Other Loans Especially Mentioned [Member] | Personal
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	49		0	0
Performing [Member] | Substandard [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	327,315		398,966	500,864
Performing [Member] | Substandard [Member] | Commercial
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	320,786		390,272	486,094
Performing [Member] | Substandard [Member] | Commercial | Energy [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	226,407		307,996	421,025
Performing [Member] | Substandard [Member] | Commercial | Services [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	17,111		37,855	9,916
Performing [Member] | Substandard [Member] | Commercial | Wholesale/retail [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	9,788		13,062	26,624
Performing [Member] | Substandard [Member] | Commercial | Manufacturing [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	16,499		15,198	19,612
Performing [Member] | Substandard [Member] | Commercial | Healthcare [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	33,120		16,161	8,917
Performing [Member] | Substandard [Member] | Commercial | Other commercial and industrial [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	17,861		0	0
Performing [Member] | Substandard [Member] | Commercial real estate
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	5,174		5,309	7,774
Performing [Member] | Substandard [Member] | Commercial real estate | Residential construction and land development [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	751		470	972
Performing [Member] | Substandard [Member] | Commercial real estate | Retail [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	0		399	413
Performing [Member] | Substandard [Member] | Commercial real estate | Office [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	0		0	304
Performing [Member] | Substandard [Member] | Commercial real estate | Multifamily [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	4,420		4,434	6,077
Performing [Member] | Substandard [Member] | Commercial real estate | Industrial [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	0		0	0
Performing [Member] | Substandard [Member] | Commercial real estate | Other commercial real estate [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	3		6	8
Performing [Member] | Substandard [Member] | Residential mortgage
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	478		2,331	3,406
Performing [Member] | Substandard [Member] | Residential mortgage | Permanent mortgage [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	478		2,331	3,406
Performing [Member] | Substandard [Member] | Residential mortgage | Permanent mortgages guaranteed by US government agencies [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	0		0	0
Performing [Member] | Substandard [Member] | Residential mortgage | Home equity [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	0		0	0
Performing [Member] | Substandard [Member] | Personal
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	877		1,054	3,590
Nonaccrual [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	202,189		185,930	192,777
Non-Graded, Recorded Investment	43,250		45,054	54,407
Nonaccrual [Member] | Commercial
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	197,053		178,895	181,926
Non-Graded, Recorded Investment	104		58	63
Nonaccrual [Member] | Commercial | Energy [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	123,992		132,499	168,145
Non-Graded, Recorded Investment	0		0	0
Nonaccrual [Member] | Commercial | Services [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	7,754		8,173	9,388
Non-Graded, Recorded Investment	0		0	0
Nonaccrual [Member] | Commercial | Wholesale/retail [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	10,620		11,407	2,772
Non-Graded, Recorded Investment	0		0	0
Nonaccrual [Member] | Commercial | Manufacturing [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	9,656		4,931	293
Non-Graded, Recorded Investment	0		0	0
Nonaccrual [Member] | Commercial | Healthcare [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	24,505		825	875
Non-Graded, Recorded Investment	0		0	0
Nonaccrual [Member] | Commercial | Other commercial and industrial [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	20,526		21,060	453
Non-Graded, Recorded Investment	104		58	63
Nonaccrual [Member] | Commercial real estate
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	3,775		5,521	7,780
Non-Graded, Recorded Investment	0		0	0
Nonaccrual [Member] | Commercial real estate | Residential construction and land development [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	2,051		3,433	4,261
Non-Graded, Recorded Investment	0		0	0
Nonaccrual [Member] | Commercial real estate | Retail [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	301		326	1,265
Non-Graded, Recorded Investment	0		0	0
Nonaccrual [Member] | Commercial real estate | Office [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	396		426	606
Non-Graded, Recorded Investment	0		0	0
Nonaccrual [Member] | Commercial real estate | Multifamily [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	10		38	65
Non-Graded, Recorded Investment	0		0	0
Nonaccrual [Member] | Commercial real estate | Industrial [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	0		76	76
Non-Graded, Recorded Investment	0		0	0
Nonaccrual [Member] | Commercial real estate | Other commercial real estate [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	1,017		1,222	1,507
Non-Graded, Recorded Investment	0		0	0
Nonaccrual [Member] | Residential mortgage
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	1,273		1,417	2,955
Non-Graded, Recorded Investment	42,962		44,803	54,106
Nonaccrual [Member] | Residential mortgage | Permanent mortgage [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	1,273		1,417	2,955
Non-Graded, Recorded Investment	22,142		21,438	24,273
Nonaccrual [Member] | Residential mortgage | Permanent mortgages guaranteed by US government agencies [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	0		0	0
Non-Graded, Recorded Investment	9,100		12,000	20,000
Nonaccrual [Member] | Residential mortgage | Home equity [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	0		0	0
Non-Graded, Recorded Investment	11,768		11,519	10,092
Nonaccrual [Member] | Personal
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	88		97	116
Non-Graded, Recorded Investment	$ 184		$ 193	$ 238

Loans and Allowance for Credi44

Loans and Allowance for Credit Losses, Impaired Loans (Details) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2017		Jun. 30, 2016		Jun. 30, 2017		Jun. 30, 2016		Dec. 31, 2016
Impaired loans [Abstract]
Impaired loans, unpaid principal balance	$ 480,181		$ 496,841		$ 480,181		$ 496,841		$ 473,526
Impaired loans, recorded investment, total	428,116		420,175		428,116		420,175		418,525
Impaired loans, recorded investment with no related allowance	355,469		388,031		355,469		388,031		407,363
Impaired loans, recorded investment with related allowance	72,647		32,144		72,647		32,144		11,162
Impaired loans, related allowance	9,693		4,310		9,693		4,310		843
Impaired loans, average recorded investment	419,893		416,291		432,921		355,154
Impaired loans, interest income recognized	2,328		2,327		4,523		4,426
Commercial
Impaired loans [Abstract]
Impaired loans, unpaid principal balance	233,643		233,857		233,643		233,857		211,762
Impaired loans, recorded investment, total	197,157		181,989		197,157		181,989		178,953
Impaired loans, recorded investment with no related allowance	124,510		150,108		124,510		150,108		167,837
Impaired loans, recorded investment with related allowance	72,647		31,881		72,647		31,881		11,116
Impaired loans, related allowance	9,693		4,228		9,693		4,228		797
Impaired loans, average recorded investment	176,992		178,322		188,055		112,462
Impaired loans, interest income recognized	0		0		0		0
Commercial | Energy [Member]
Impaired loans [Abstract]
Impaired loans, unpaid principal balance	141,091		202,369		141,091		202,369		146,897
Impaired loans, recorded investment, total	123,992		168,145		123,992		168,145		132,499
Impaired loans, recorded investment with no related allowance	56,988		136,264		56,988		136,264		121,418
Impaired loans, recorded investment with related allowance	67,004		31,881		67,004		31,881		11,081
Impaired loans, related allowance	8,874		4,228		8,874		4,228		762
Impaired loans, average recorded investment	117,209		163,849		128,246		97,923
Impaired loans, interest income recognized	0		0		0		0
Commercial | Services [Member]
Impaired loans [Abstract]
Impaired loans, unpaid principal balance	11,209		12,780		11,209		12,780		11,723
Impaired loans, recorded investment, total	7,754		9,388		7,754		9,388		8,173
Impaired loans, recorded investment with no related allowance	7,754		9,388		7,754		9,388		8,173
Impaired loans, recorded investment with related allowance	0		0		0		0		0
Impaired loans, related allowance	0		0		0		0		0
Impaired loans, average recorded investment	7,734		9,450		7,964		9,839
Impaired loans, interest income recognized	0		0		0		0
Commercial | Wholesale/retail [Member]
Impaired loans [Abstract]
Impaired loans, unpaid principal balance	17,392		8,697		17,392		8,697		17,669
Impaired loans, recorded investment, total	10,620		2,772		10,620		2,772		11,407
Impaired loans, recorded investment with no related allowance	10,620		2,772		10,620		2,772		11,407
Impaired loans, recorded investment with related allowance	0		0		0		0		0
Impaired loans, related allowance	0		0		0		0		0
Impaired loans, average recorded investment	10,855		3,229		11,013		2,846
Impaired loans, interest income recognized	0		0		0		0
Commercial | Manufacturing [Member]
Impaired loans [Abstract]
Impaired loans, unpaid principal balance	10,223		650		10,223		650		5,320
Impaired loans, recorded investment, total	9,656		293		9,656		293		4,931
Impaired loans, recorded investment with no related allowance	9,656		293		9,656		293		4,931
Impaired loans, recorded investment with related allowance	0		0		0		0		0
Impaired loans, related allowance	0		0		0		0		0
Impaired loans, average recorded investment	7,781		303		7,293		312
Impaired loans, interest income recognized	0		0		0		0
Commercial | Healthcare [Member]
Impaired loans [Abstract]
Impaired loans, unpaid principal balance	24,795		1,175		24,795		1,175		1,147
Impaired loans, recorded investment, total	24,505		875		24,505		875		825
Impaired loans, recorded investment with no related allowance	18,883		875		18,883		875		825
Impaired loans, recorded investment with related allowance	5,622		0		5,622		0		0
Impaired loans, related allowance	802		0		802		0		0
Impaired loans, average recorded investment	12,707		949		12,665		973
Impaired loans, interest income recognized	0		0		0		0
Commercial | Other commercial and industrial [Member]
Impaired loans [Abstract]
Impaired loans, unpaid principal balance	28,933		8,186		28,933		8,186		29,006
Impaired loans, recorded investment, total	20,630		516		20,630		516		21,118
Impaired loans, recorded investment with no related allowance	20,609		516		20,609		516		21,083
Impaired loans, recorded investment with related allowance	21		0		21		0		35
Impaired loans, related allowance	17		0		17		0		35
Impaired loans, average recorded investment	20,706		542		20,874		569
Impaired loans, interest income recognized	0		0		0		0
Commercial real estate
Impaired loans [Abstract]
Impaired loans, unpaid principal balance	6,905		18,519		6,905		18,519		14,427
Impaired loans, recorded investment, total	3,775		7,780		3,775		7,780		5,521
Impaired loans, recorded investment with no related allowance	3,775		7,628		3,775		7,628		5,521
Impaired loans, recorded investment with related allowance	0		152		0		152		0
Impaired loans, related allowance	0		18		0		18		0
Impaired loans, average recorded investment	4,125		8,524		4,648		8,390
Impaired loans, interest income recognized	0		0		0		0
Commercial real estate | Residential construction and land development [Member]
Impaired loans [Abstract]
Impaired loans, unpaid principal balance	3,676		7,177		3,676		7,177		4,951
Impaired loans, recorded investment, total	2,051		4,261		2,051		4,261		3,433
Impaired loans, recorded investment with no related allowance	2,051		4,261		2,051		4,261		3,433
Impaired loans, recorded investment with related allowance	0		0		0		0		0
Impaired loans, related allowance	0		0		0		0		0
Impaired loans, average recorded investment	2,334		4,525		2,742		4,335
Impaired loans, interest income recognized	0		0		0		0
Commercial real estate | Retail [Member]
Impaired loans [Abstract]
Impaired loans, unpaid principal balance	518		1,914		518		1,914		530
Impaired loans, recorded investment, total	301		1,265		301		1,265		326
Impaired loans, recorded investment with no related allowance	301		1,265		301		1,265		326
Impaired loans, recorded investment with related allowance	0		0		0		0		0
Impaired loans, related allowance	0		0		0		0		0
Impaired loans, average recorded investment	308		1,283		314		1,292
Impaired loans, interest income recognized	0		0		0		0
Commercial real estate | Office [Member]
Impaired loans [Abstract]
Impaired loans, unpaid principal balance	499		907		499		907		521
Impaired loans, recorded investment, total	396		606		396		606		426
Impaired loans, recorded investment with no related allowance	396		606		396		606		426
Impaired loans, recorded investment with related allowance	0		0		0		0		0
Impaired loans, related allowance	0		0		0		0		0
Impaired loans, average recorded investment	404		618		411		628
Impaired loans, interest income recognized	0		0		0		0
Commercial real estate | Multifamily [Member]
Impaired loans [Abstract]
Impaired loans, unpaid principal balance	1,000		1,000		1,000		1,000		1,000
Impaired loans, recorded investment, total	10		65		10		65		38
Impaired loans, recorded investment with no related allowance	10		65		10		65		38
Impaired loans, recorded investment with related allowance	0		0		0		0		0
Impaired loans, related allowance	0		0		0		0		0
Impaired loans, average recorded investment	17		157		24		169
Impaired loans, interest income recognized	0		0		0		0
Commercial real estate | Industrial [Member]
Impaired loans [Abstract]
Impaired loans, unpaid principal balance	0		76		0		76		76
Impaired loans, recorded investment, total	0		76		0		76		76
Impaired loans, recorded investment with no related allowance	0		76		0		76		76
Impaired loans, recorded investment with related allowance	0		0		0		0		0
Impaired loans, related allowance	0		0		0		0		0
Impaired loans, average recorded investment	38		76		38		76
Impaired loans, interest income recognized	0		0		0		0
Commercial real estate | Other commercial real estate [Member]
Impaired loans [Abstract]
Impaired loans, unpaid principal balance	1,212		7,445		1,212		7,445		7,349
Impaired loans, recorded investment, total	1,017		1,507		1,017		1,507		1,222
Impaired loans, recorded investment with no related allowance	1,017		1,355		1,017		1,355		1,222
Impaired loans, recorded investment with related allowance	0		152		0		152		0
Impaired loans, related allowance	0		18		0		18		0
Impaired loans, average recorded investment	1,024		1,865		1,119		1,890
Impaired loans, interest income recognized	0		0		0		0
Residential mortgage
Impaired loans [Abstract]
Impaired loans, unpaid principal balance	239,326		243,291		239,326		243,291		247,005
Impaired loans, recorded investment, total	226,912		230,052		226,912		230,052		233,761
Impaired loans, recorded investment with no related allowance	226,912		229,941		226,912		229,941		233,715
Impaired loans, recorded investment with related allowance	0		111		0		111		46
Impaired loans, related allowance	0		64		0		64		46
Impaired loans, average recorded investment	238,523		229,103		239,937		233,893
Impaired loans, interest income recognized	2,328		2,327		4,523		4,426
Residential mortgage | Permanent mortgage [Member]
Impaired loans [Abstract]
Impaired loans, unpaid principal balance	28,603		33,793		28,603		33,793		28,830
Impaired loans, recorded investment, total	23,415		27,228		23,415		27,228		22,855
Impaired loans, recorded investment with no related allowance	23,415		27,117		23,415		27,117		22,809
Impaired loans, recorded investment with related allowance	0		111		0		111		46
Impaired loans, related allowance	0		64		0		64		46
Impaired loans, average recorded investment	23,801		27,362		23,135		28,106
Impaired loans, interest income recognized	307		304		598		631
Residential mortgage | Permanent mortgages guaranteed by US government agencies [Member]
Impaired loans [Abstract]
Impaired loans, unpaid principal balance	197,659	[1]	198,534	[2]	197,659	[1]	198,534	[2]	205,564	[3]
Impaired loans, recorded investment, total	191,729	[1]	192,732	[2]	191,729	[1]	192,732	[2]	199,387	[3]
Impaired loans, recorded investment with no related allowance	191,729	[1]	192,732	[2]	191,729	[1]	192,732	[2]	199,387	[3]
Impaired loans, recorded investment with related allowance	0	[1]	0	[2]	0	[1]	0	[2]	0	[3]
Impaired loans, related allowance	0	[1]	0	[2]	0	[1]	0	[2]	0	[3]
Impaired loans, average recorded investment	202,946	[1]	191,430	[2]	205,159	[1]	195,563	[2]
Impaired loans, interest income recognized	2,021	[1]	2,023	[2]	3,925	[1]	3,795	[2]
Residential mortgage | Home equity [Member]
Impaired loans [Abstract]
Impaired loans, unpaid principal balance	13,064		10,964		13,064		10,964		12,611
Impaired loans, recorded investment, total	11,768		10,092		11,768		10,092		11,519
Impaired loans, recorded investment with no related allowance	11,768		10,092		11,768		10,092		11,519
Impaired loans, recorded investment with related allowance	0		0		0		0		0
Impaired loans, related allowance	0		0		0		0		0
Impaired loans, average recorded investment	11,776		10,311		11,643		10,224
Impaired loans, interest income recognized	0		0		0		0
Personal
Impaired loans [Abstract]
Impaired loans, unpaid principal balance	307		1,174		307		1,174		332
Impaired loans, recorded investment, total	272		354		272		354		290
Impaired loans, recorded investment with no related allowance	272		354		272		354		290
Impaired loans, recorded investment with related allowance	0		0		0		0		0
Impaired loans, related allowance	0		0		0		0		$ 0
Impaired loans, average recorded investment	253		342		281		409
Impaired loans, interest income recognized	$ 0		$ 0		$ 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 June 30, 2017, $9.1 million of these loans were nonaccruing and $183 million were 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 June 30, 2016, $20 million of these loans were nonaccruing and $173 million were accruing based on the guarantee by U.S. government agencies.
[3]	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 were nonaccruing and $188 million were accruing based on the guarantee by U.S. government agencies.

Loans and Allowances for Cred45

Loans and Allowances for Credit Losses, Troubled Debt Restructurings (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Financing Receivable, Modifications [Line Items]
Troubled Debt Restructuring, Recorded Investment	$ 168,739	$ 129,485	$ 168,739	$ 129,485	$ 147,117
Troubled Debt Restructuring, Performing in Accordance With Modified Terms	70,906	60,646	70,906	60,646	74,738
Troubled Debt Restructuring, Not Performing in Accordance With Modified Terms	97,833	68,839	97,833	68,839	72,379
Troubled Debt Restructuring, Specific allowance	4,308	64	4,308	64	46
Troubled Debt Restructuring, Charge-offs	10	600	42	744
Nonaccrual [Member]
Financing Receivable, Modifications [Line Items]
Troubled Debt Restructuring, Recorded Investment	88,115	50,679	88,115	50,679	65,747
Troubled Debt Restructuring, Performing in Accordance With Modified Terms	46,400	32,647	46,400	32,647	47,449
Troubled Debt Restructuring, Not Performing in Accordance With Modified Terms	41,715	18,032	41,715	18,032	18,298
Troubled Debt Restructuring, Specific allowance	4,308	64	4,308	64	46
Troubled Debt Restructuring, Charge-offs	10	600	42	744
Nonaccrual [Member] | Commercial
Financing Receivable, Modifications [Line Items]
Troubled Debt Restructuring, Recorded Investment	60,924	14,732	60,924	14,732	36,879
Troubled Debt Restructuring, Performing in Accordance With Modified Terms	30,007	11,236	30,007	11,236	29,225
Troubled Debt Restructuring, Not Performing in Accordance With Modified Terms	30,917	3,496	30,917	3,496	7,654
Troubled Debt Restructuring, Specific allowance	4,308	0	4,308	0	0
Troubled Debt Restructuring, Charge-offs	3	500	3	557
Nonaccrual [Member] | Commercial | Energy [Member]
Financing Receivable, Modifications [Line Items]
Troubled Debt Restructuring, Recorded Investment	22,466	2,246	22,466	2,246	16,893
Troubled Debt Restructuring, Performing in Accordance With Modified Terms	12,692	0	12,692	0	10,867
Troubled Debt Restructuring, Not Performing in Accordance With Modified Terms	9,774	2,246	9,774	2,246	6,026
Troubled Debt Restructuring, Specific allowance	4,308	0	4,308	0	0
Troubled Debt Restructuring, Charge-offs	0	500	0	500
Nonaccrual [Member] | Commercial | Services [Member]
Financing Receivable, Modifications [Line Items]
Troubled Debt Restructuring, Recorded Investment	7,208	8,610	7,208	8,610	7,527
Troubled Debt Restructuring, Performing in Accordance With Modified Terms	6,561	7,853	6,561	7,853	6,830
Troubled Debt Restructuring, Not Performing in Accordance With Modified Terms	647	757	647	757	697
Troubled Debt Restructuring, Specific allowance	0	0	0	0	0
Troubled Debt Restructuring, Charge-offs	3	0	3	0
Nonaccrual [Member] | Commercial | Wholesale/retail [Member]
Financing Receivable, Modifications [Line Items]
Troubled Debt Restructuring, Recorded Investment	10,524	2,467	10,524	2,467	11,291
Troubled Debt Restructuring, Performing in Accordance With Modified Terms	10,524	2,427	10,524	2,427	11,251
Troubled Debt Restructuring, Not Performing in Accordance With Modified Terms	0	40	0	40	40
Troubled Debt Restructuring, Specific allowance	0	0	0	0	0
Troubled Debt Restructuring, Charge-offs	0	0	0	0
Nonaccrual [Member] | Commercial | Manufacturing [Member]
Financing Receivable, Modifications [Line Items]
Troubled Debt Restructuring, Recorded Investment	195	253	195	253	224
Troubled Debt Restructuring, Performing in Accordance With Modified Terms	195	253	195	253	224
Troubled Debt Restructuring, Not Performing in Accordance With Modified Terms	0	0	0	0	0
Troubled Debt Restructuring, Specific allowance	0	0	0	0	0
Troubled Debt Restructuring, Charge-offs	0	0	0	0
Nonaccrual [Member] | Commercial | Healthcare [Member]
Financing Receivable, Modifications [Line Items]
Troubled Debt Restructuring, Recorded Investment	0	640	0	640	607
Troubled Debt Restructuring, Performing in Accordance With Modified Terms	0	640	0	640	0
Troubled Debt Restructuring, Not Performing in Accordance With Modified Terms	0	0	0	0	607
Troubled Debt Restructuring, Specific allowance	0	0	0	0	0
Troubled Debt Restructuring, Charge-offs	0	0	0	0
Nonaccrual [Member] | Commercial | Other commercial and industrial [Member]
Financing Receivable, Modifications [Line Items]
Troubled Debt Restructuring, Recorded Investment	20,531	516	20,531	516	337
Troubled Debt Restructuring, Performing in Accordance With Modified Terms	35	63	35	63	53
Troubled Debt Restructuring, Not Performing in Accordance With Modified Terms	20,496	453	20,496	453	284
Troubled Debt Restructuring, Specific allowance	0	0	0	0	0
Troubled Debt Restructuring, Charge-offs	0	0	0	57
Nonaccrual [Member] | Commercial real estate
Financing Receivable, Modifications [Line Items]
Troubled Debt Restructuring, Recorded Investment	1,168	3,810	1,168	3,810	1,707
Troubled Debt Restructuring, Performing in Accordance With Modified Terms	811	2,510	811	2,510	1,114
Troubled Debt Restructuring, Not Performing in Accordance With Modified Terms	357	1,300	357	1,300	593
Troubled Debt Restructuring, Specific allowance	0	0	0	0	0
Troubled Debt Restructuring, Charge-offs	0	0	0	0
Nonaccrual [Member] | Commercial real estate | Residential construction and land development [Member]
Financing Receivable, Modifications [Line Items]
Troubled Debt Restructuring, Recorded Investment	381	1,601	381	1,601	690
Troubled Debt Restructuring, Performing in Accordance With Modified Terms	145	1,079	145	1,079	97
Troubled Debt Restructuring, Not Performing in Accordance With Modified Terms	236	522	236	522	593
Troubled Debt Restructuring, Specific allowance	0	0	0	0	0
Troubled Debt Restructuring, Charge-offs	0	0	0	0
Nonaccrual [Member] | Commercial real estate | Retail [Member]
Financing Receivable, Modifications [Line Items]
Troubled Debt Restructuring, Recorded Investment	301	1,264	301	1,264	326
Troubled Debt Restructuring, Performing in Accordance With Modified Terms	301	907	301	907	326
Troubled Debt Restructuring, Not Performing in Accordance With Modified Terms	0	357	0	357	0
Troubled Debt Restructuring, Specific allowance	0	0	0	0	0
Troubled Debt Restructuring, Charge-offs	0	0	0	0
Nonaccrual [Member] | Commercial real estate | Office [Member]
Financing Receivable, Modifications [Line Items]
Troubled Debt Restructuring, Recorded Investment	121	152	121	152	143
Troubled Debt Restructuring, Performing in Accordance With Modified Terms	0	152	0	152	143
Troubled Debt Restructuring, Not Performing in Accordance With Modified Terms	121	0	121	0	0
Troubled Debt Restructuring, Specific allowance	0	0	0	0	0
Troubled Debt Restructuring, Charge-offs	0	0	0	0
Nonaccrual [Member] | Commercial real estate | Multifamily [Member]
Financing Receivable, Modifications [Line Items]
Troubled Debt Restructuring, Recorded Investment	0	0	0	0	0
Troubled Debt Restructuring, Performing in Accordance With Modified Terms	0	0	0	0	0
Troubled Debt Restructuring, Not Performing in Accordance With Modified Terms	0	0	0	0	0
Troubled Debt Restructuring, Specific allowance	0	0	0	0	0
Troubled Debt Restructuring, Charge-offs	0	0	0	0
Nonaccrual [Member] | Commercial real estate | Industrial [Member]
Financing Receivable, Modifications [Line Items]
Troubled Debt Restructuring, Recorded Investment	0	0	0	0	0
Troubled Debt Restructuring, Performing in Accordance With Modified Terms	0	0	0	0	0
Troubled Debt Restructuring, Not Performing in Accordance With Modified Terms	0	0	0	0	0
Troubled Debt Restructuring, Specific allowance	0	0	0	0	0
Troubled Debt Restructuring, Charge-offs	0	0	0	0
Nonaccrual [Member] | Commercial real estate | Other commercial real estate [Member]
Financing Receivable, Modifications [Line Items]
Troubled Debt Restructuring, Recorded Investment	365	793	365	793	548
Troubled Debt Restructuring, Performing in Accordance With Modified Terms	365	372	365	372	548
Troubled Debt Restructuring, Not Performing in Accordance With Modified Terms	0	421	0	421	0
Troubled Debt Restructuring, Specific allowance	0	0	0	0	0
Troubled Debt Restructuring, Charge-offs	0	0	0	0
Nonaccrual [Member] | Residential mortgage
Financing Receivable, Modifications [Line Items]
Troubled Debt Restructuring, Recorded Investment	25,795	31,839	25,795	31,839	26,924
Troubled Debt Restructuring, Performing in Accordance With Modified Terms	15,354	18,625	15,354	18,625	16,874
Troubled Debt Restructuring, Not Performing in Accordance With Modified Terms	10,441	13,214	10,441	13,214	10,050
Troubled Debt Restructuring, Specific allowance	0	64	0	64	46
Troubled Debt Restructuring, Charge-offs	0	97	31	178
Nonaccrual [Member] | Residential mortgage | Permanent mortgage [Member]
Financing Receivable, Modifications [Line Items]
Troubled Debt Restructuring, Recorded Investment	14,284	17,367	14,284	17,367	14,876
Troubled Debt Restructuring, Performing in Accordance With Modified Terms	9,939	12,462	9,939	12,462	10,175
Troubled Debt Restructuring, Not Performing in Accordance With Modified Terms	4,345	4,905	4,345	4,905	4,701
Troubled Debt Restructuring, Specific allowance	0	64	0	64	46
Troubled Debt Restructuring, Charge-offs	0	37	0	52
Nonaccrual [Member] | Residential mortgage | Permanent mortgages guaranteed by US government agencies [Member]
Financing Receivable, Modifications [Line Items]
Troubled Debt Restructuring, Recorded Investment	5,962	9,709	5,962	9,709	6,702
Troubled Debt Restructuring, Performing in Accordance With Modified Terms	1,176	2,024	1,176	2,024	2,241
Troubled Debt Restructuring, Not Performing in Accordance With Modified Terms	4,786	7,685	4,786	7,685	4,461
Troubled Debt Restructuring, Specific allowance	0	0	0	0	0
Troubled Debt Restructuring, Charge-offs	0	0	0	0
Nonaccrual [Member] | Residential mortgage | Home equity [Member]
Financing Receivable, Modifications [Line Items]
Troubled Debt Restructuring, Recorded Investment	5,549	4,763	5,549	4,763	5,346
Troubled Debt Restructuring, Performing in Accordance With Modified Terms	4,239	4,139	4,239	4,139	4,458
Troubled Debt Restructuring, Not Performing in Accordance With Modified Terms	1,310	624	1,310	624	888
Troubled Debt Restructuring, Specific allowance	0	0	0	0	0
Troubled Debt Restructuring, Charge-offs	0	60	31	126
Nonaccrual [Member] | Personal
Financing Receivable, Modifications [Line Items]
Troubled Debt Restructuring, Recorded Investment	228	298	228	298	237
Troubled Debt Restructuring, Performing in Accordance With Modified Terms	228	276	228	276	236
Troubled Debt Restructuring, Not Performing in Accordance With Modified Terms	0	22	0	22	1
Troubled Debt Restructuring, Specific allowance	0	0	0	0	0
Troubled Debt Restructuring, Charge-offs	7	3	8	9
Accruing [Member] | Residential mortgage | Permanent mortgages guaranteed by US government agencies [Member]
Financing Receivable, Modifications [Line Items]
Troubled Debt Restructuring, Recorded Investment	80,624	78,806	80,624	78,806	81,370
Troubled Debt Restructuring, Performing in Accordance With Modified Terms	24,506	27,999	24,506	27,999	27,289
Troubled Debt Restructuring, Not Performing in Accordance With Modified Terms	56,118	50,807	56,118	50,807	54,081
Troubled Debt Restructuring, Specific allowance	0	0	0	0	$ 0
Troubled Debt Restructuring, Charge-offs	$ 0	$ 0	$ 0	$ 0

Loans and Allowances for Cred46

Loans and Allowances for Credit Losses, Troubled Debt Restructurings, Modifications (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	$ 33,892	$ 10,172	$ 53,146	$ 18,770
Troubled Debt Restructurings, Recorded Balance With Payment Default	54,442	23,165	54,947	25,911
Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	20,868	0	33,878	501
Troubled Debt Restructurings, Recorded Balance With Payment Default	30,016	2,246	30,016	2,246
Commercial | Energy [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0	13,010	501
Troubled Debt Restructurings, Recorded Balance With Payment Default	9,774	2,246	9,774	2,246
Commercial | Services [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0	0	0
Troubled Debt Restructurings, Recorded Balance With Payment Default	0	0	0	0
Commercial | Wholesale/retail [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	626	0	626	0
Troubled Debt Restructurings, Recorded Balance With Payment Default	0	0	0	0
Commercial | Manufacturing [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0	0	0
Troubled Debt Restructurings, Recorded Balance With Payment Default	0	0	0	0
Commercial | Healthcare [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0	0	0
Troubled Debt Restructurings, Recorded Balance With Payment Default	0	0	0	0
Commercial | Other commercial and industrial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	20,242	0	20,242	0
Troubled Debt Restructurings, Recorded Balance With Payment Default	20,242	0	20,242	0
Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0	0	0
Troubled Debt Restructurings, Recorded Balance With Payment Default	0	0	0	0
Commercial real estate | 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	0	0
Troubled Debt Restructurings, Recorded Balance With Payment Default	0	0	0	0
Commercial real estate | Retail [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0	0	0
Troubled Debt Restructurings, Recorded Balance With Payment Default	0	0	0	0
Commercial real estate | Office [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0	0	0
Troubled Debt Restructurings, Recorded Balance With Payment Default	0	0	0	0
Commercial real estate | Multifamily [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0	0	0
Troubled Debt Restructurings, Recorded Balance With Payment Default	0	0	0	0
Commercial real estate | Industrial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0	0	0
Troubled Debt Restructurings, Recorded Balance With Payment Default	0	0	0	0
Commercial real estate | Other commercial real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0	0	0
Troubled Debt Restructurings, Recorded Balance With Payment Default	0	0	0	0
Residential mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	12,977	10,107	19,217	18,197
Troubled Debt Restructurings, Recorded Balance With Payment Default	24,426	20,919	24,931	23,665
Residential mortgage | Permanent mortgage [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	191	1,867	237	2,290
Troubled Debt Restructurings, Recorded Balance With Payment Default	161	788	161	1,806
Residential mortgage | Permanent mortgages guaranteed by US government agencies [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	12,201	7,863	17,778	15,068
Troubled Debt Restructurings, Recorded Balance With Payment Default	23,152	19,899	23,508	21,627
Residential mortgage | Home equity [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	585	377	1,202	839
Troubled Debt Restructurings, Recorded Balance With Payment Default	1,113	232	1,262	232
Personal
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	47	65	51	72
Troubled Debt Restructurings, Recorded Balance With Payment Default	0	0		0
Accruing [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	11,978	7,238	17,469	14,443
Troubled Debt Restructurings, Recorded Balance With Payment Default	22,234	18,893	22,590	20,621
Accruing [Member] | Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0	0	0
Troubled Debt Restructurings, Recorded Balance With Payment Default	0	0	0	0
Accruing [Member] | Commercial | Energy [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0	0	0
Troubled Debt Restructurings, Recorded Balance With Payment Default	0	0	0	0
Accruing [Member] | Commercial | Services [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0	0	0
Troubled Debt Restructurings, Recorded Balance With Payment Default	0	0	0	0
Accruing [Member] | Commercial | Wholesale/retail [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0	0	0
Troubled Debt Restructurings, Recorded Balance With Payment Default	0	0	0	0
Accruing [Member] | Commercial | Manufacturing [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0	0	0
Troubled Debt Restructurings, Recorded Balance With Payment Default	0	0	0	0
Accruing [Member] | Commercial | Healthcare [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0	0	0
Troubled Debt Restructurings, Recorded Balance With Payment Default	0	0	0	0
Accruing [Member] | Commercial | Other commercial and industrial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0	0	0
Troubled Debt Restructurings, Recorded Balance With Payment Default	0	0	0	0
Accruing [Member] | Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0	0	0
Troubled Debt Restructurings, Recorded Balance With Payment Default	0	0	0	0
Accruing [Member] | Commercial real estate | 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	0	0
Troubled Debt Restructurings, Recorded Balance With Payment Default	0	0		0
Accruing [Member] | Commercial real estate | Retail [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0	0	0
Troubled Debt Restructurings, Recorded Balance With Payment Default	0	0		0
Accruing [Member] | Commercial real estate | Office [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0	0	0
Troubled Debt Restructurings, Recorded Balance With Payment Default	0	0		0
Accruing [Member] | Commercial real estate | Multifamily [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0	0	0
Troubled Debt Restructurings, Recorded Balance With Payment Default	0	0		0
Accruing [Member] | Commercial real estate | Industrial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0	0	0
Troubled Debt Restructurings, Recorded Balance With Payment Default	0	0		0
Accruing [Member] | Commercial real estate | Other commercial real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0	0	0
Troubled Debt Restructurings, Recorded Balance With Payment Default	0	0		0
Accruing [Member] | Residential mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	11,978	7,238	17,469	14,443
Troubled Debt Restructurings, Recorded Balance With Payment Default	22,234	18,893	22,590	20,621
Accruing [Member] | Residential mortgage | Permanent mortgage [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0	0	0
Troubled Debt Restructurings, Recorded Balance With Payment Default	0	0	0	0
Accruing [Member] | Residential mortgage | Permanent mortgages guaranteed by US government agencies [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	11,978	7,238	17,469	14,443
Troubled Debt Restructurings, Recorded Balance With Payment Default	22,234	18,893	22,590	20,621
Accruing [Member] | Residential mortgage | Home equity [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0	0	0
Troubled Debt Restructurings, Recorded Balance With Payment Default	0	0	0	0
Accruing [Member] | Personal
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0	0	0
Troubled Debt Restructurings, Recorded Balance With Payment Default	0	0		0
Accruing [Member] | Payment Stream [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	10,410	2,783	14,883	6,625
Accruing [Member] | Payment Stream [Member] | Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0	0	0
Accruing [Member] | Payment Stream [Member] | Commercial | Energy [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0	0	0
Accruing [Member] | Payment Stream [Member] | Commercial | Services [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0	0	0
Accruing [Member] | Payment Stream [Member] | Commercial | Wholesale/retail [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0	0	0
Accruing [Member] | Payment Stream [Member] | Commercial | Manufacturing [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0	0	0
Accruing [Member] | Payment Stream [Member] | Commercial | Healthcare [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0	0	0
Accruing [Member] | Payment Stream [Member] | Commercial | Other commercial and industrial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0	0	0
Accruing [Member] | Payment Stream [Member] | Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0	0	0
Accruing [Member] | Payment Stream [Member] | Commercial real estate | 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	0	0
Accruing [Member] | Payment Stream [Member] | Commercial real estate | Retail [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0	0	0
Accruing [Member] | Payment Stream [Member] | Commercial real estate | Office [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0	0	0
Accruing [Member] | Payment Stream [Member] | Commercial real estate | Multifamily [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0	0	0
Accruing [Member] | Payment Stream [Member] | Commercial real estate | Industrial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0	0	0
Accruing [Member] | Payment Stream [Member] | Commercial real estate | Other commercial real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0	0	0
Accruing [Member] | Payment Stream [Member] | Residential mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	10,410	2,783	14,883	6,625
Accruing [Member] | Payment Stream [Member] | Residential mortgage | Permanent mortgage [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0	0	0
Accruing [Member] | Payment Stream [Member] | Residential mortgage | Permanent mortgages guaranteed by US government agencies [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	10,410	2,783	14,883	6,625
Accruing [Member] | Payment Stream [Member] | Residential mortgage | Home equity [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0	0	0
Accruing [Member] | Payment Stream [Member] | Personal
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0	0	0
Accruing [Member] | Combination & Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	1,568	4,455	2,586	7,818
Accruing [Member] | Combination & Other [Member] | Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0	0	0
Accruing [Member] | Combination & Other [Member] | Commercial | Energy [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0	0	0
Accruing [Member] | Combination & Other [Member] | Commercial | Services [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0	0	0
Accruing [Member] | Combination & Other [Member] | Commercial | Wholesale/retail [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0	0	0
Accruing [Member] | Combination & Other [Member] | Commercial | Manufacturing [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0	0	0
Accruing [Member] | Combination & Other [Member] | Commercial | Healthcare [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0	0	0
Accruing [Member] | Combination & Other [Member] | Commercial | Other commercial and industrial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0	0	0
Accruing [Member] | Combination & Other [Member] | Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0	0	0
Accruing [Member] | Combination & Other [Member] | Commercial real estate | 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	0	0
Accruing [Member] | Combination & Other [Member] | Commercial real estate | Retail [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0	0	0
Accruing [Member] | Combination & Other [Member] | Commercial real estate | Office [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0	0	0
Accruing [Member] | Combination & Other [Member] | Commercial real estate | Multifamily [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0	0	0
Accruing [Member] | Combination & Other [Member] | Commercial real estate | Industrial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0	0	0
Accruing [Member] | Combination & Other [Member] | Commercial real estate | Other commercial real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0	0	0
Accruing [Member] | Combination & Other [Member] | Residential mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	1,568	4,455	2,586	7,818
Accruing [Member] | Combination & Other [Member] | Residential mortgage | Permanent mortgage [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0	0	0
Accruing [Member] | Combination & Other [Member] | Residential mortgage | Permanent mortgages guaranteed by US government agencies [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	1,568	4,455	2,586	7,818
Accruing [Member] | Combination & Other [Member] | Residential mortgage | Home equity [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0	0	0
Accruing [Member] | Combination & Other [Member] | Personal
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0	0	0
Nonaccrual [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	21,914	2,934	35,677	4,327
Troubled Debt Restructurings, Recorded Balance With Payment Default	32,208	4,272	32,357	5,290
Nonaccrual [Member] | Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	20,868	0	33,878	501
Troubled Debt Restructurings, Recorded Balance With Payment Default	30,016	2,246	30,016	2,246
Nonaccrual [Member] | Commercial | Energy [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0	13,010	501
Troubled Debt Restructurings, Recorded Balance With Payment Default	9,774	2,246	9,774	2,246
Nonaccrual [Member] | Commercial | Services [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0	0	0
Troubled Debt Restructurings, Recorded Balance With Payment Default	0	0	0	0
Nonaccrual [Member] | Commercial | Wholesale/retail [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	626	0	626	0
Troubled Debt Restructurings, Recorded Balance With Payment Default	0	0	0	0
Nonaccrual [Member] | Commercial | Manufacturing [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0	0	0
Troubled Debt Restructurings, Recorded Balance With Payment Default	0	0	0	0
Nonaccrual [Member] | Commercial | Healthcare [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0	0	0
Troubled Debt Restructurings, Recorded Balance With Payment Default	0	0	0	0
Nonaccrual [Member] | Commercial | Other commercial and industrial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	20,242	0	20,242	0
Troubled Debt Restructurings, Recorded Balance With Payment Default	20,242	0	20,242	0
Nonaccrual [Member] | Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0	0	0
Troubled Debt Restructurings, Recorded Balance With Payment Default	0	0	0	0
Nonaccrual [Member] | Commercial real estate | 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	0	0
Troubled Debt Restructurings, Recorded Balance With Payment Default	0	0		0
Nonaccrual [Member] | Commercial real estate | Retail [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0	0	0
Troubled Debt Restructurings, Recorded Balance With Payment Default	0	0		0
Nonaccrual [Member] | Commercial real estate | Office [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0	0	0
Troubled Debt Restructurings, Recorded Balance With Payment Default	0	0		0
Nonaccrual [Member] | Commercial real estate | Multifamily [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0	0	0
Troubled Debt Restructurings, Recorded Balance With Payment Default	0	0		0
Nonaccrual [Member] | Commercial real estate | Industrial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0	0	0
Troubled Debt Restructurings, Recorded Balance With Payment Default	0	0		0
Nonaccrual [Member] | Commercial real estate | Other commercial real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0	0	0
Troubled Debt Restructurings, Recorded Balance With Payment Default	0	0		0
Nonaccrual [Member] | Residential mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	999	2,869	1,748	3,754
Troubled Debt Restructurings, Recorded Balance With Payment Default	2,192	2,026	2,341	3,044
Nonaccrual [Member] | Residential mortgage | Permanent mortgage [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	191	1,867	237	2,290
Troubled Debt Restructurings, Recorded Balance With Payment Default	161	788	161	1,806
Nonaccrual [Member] | Residential mortgage | Permanent mortgages guaranteed by US government agencies [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	223	625	309	625
Troubled Debt Restructurings, Recorded Balance With Payment Default	918	1,006	918	1,006
Nonaccrual [Member] | Residential mortgage | Home equity [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	585	377	1,202	839
Troubled Debt Restructurings, Recorded Balance With Payment Default	1,113	232	1,262	232
Nonaccrual [Member] | Personal
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	47	65	51	72
Troubled Debt Restructurings, Recorded Balance With Payment Default	0	0		0
Nonaccrual [Member] | Payment Stream [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	20,629	732	33,778	1,595
Nonaccrual [Member] | Payment Stream [Member] | Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	20,242	0	33,252	501
Nonaccrual [Member] | Payment Stream [Member] | Commercial | Energy [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0	13,010	501
Nonaccrual [Member] | Payment Stream [Member] | Commercial | Services [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0	0	0
Nonaccrual [Member] | Payment Stream [Member] | Commercial | Wholesale/retail [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0	0	0
Nonaccrual [Member] | Payment Stream [Member] | Commercial | Manufacturing [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0	0	0
Nonaccrual [Member] | Payment Stream [Member] | Commercial | Healthcare [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0	0	0
Nonaccrual [Member] | Payment Stream [Member] | Commercial | Other commercial and industrial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	20,242	0	20,242	0
Nonaccrual [Member] | Payment Stream [Member] | Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0	0	0
Nonaccrual [Member] | Payment Stream [Member] | Commercial real estate | 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	0	0
Nonaccrual [Member] | Payment Stream [Member] | Commercial real estate | Retail [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0	0	0
Nonaccrual [Member] | Payment Stream [Member] | Commercial real estate | Office [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0	0	0
Nonaccrual [Member] | Payment Stream [Member] | Commercial real estate | Multifamily [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0	0	0
Nonaccrual [Member] | Payment Stream [Member] | Commercial real estate | Industrial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0	0	0
Nonaccrual [Member] | Payment Stream [Member] | Commercial real estate | Other commercial real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0	0	0
Nonaccrual [Member] | Payment Stream [Member] | Residential mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	387	732	526	1,094
Nonaccrual [Member] | Payment Stream [Member] | Residential mortgage | Permanent mortgage [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	138	684	153	1,046
Nonaccrual [Member] | Payment Stream [Member] | Residential mortgage | Permanent mortgages guaranteed by US government agencies [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	223	0	224	0
Nonaccrual [Member] | Payment Stream [Member] | Residential mortgage | Home equity [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	26	48	149	48
Nonaccrual [Member] | Payment Stream [Member] | Personal
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0	0	0
Nonaccrual [Member] | Combination & Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	1,285	2,202	1,899	2,732
Nonaccrual [Member] | Combination & Other [Member] | Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	626	0	626	0
Nonaccrual [Member] | Combination & Other [Member] | Commercial | Energy [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0	0	0
Nonaccrual [Member] | Combination & Other [Member] | Commercial | Services [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0	0	0
Nonaccrual [Member] | Combination & Other [Member] | Commercial | Wholesale/retail [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	626	0	626	0
Nonaccrual [Member] | Combination & Other [Member] | Commercial | Manufacturing [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0	0	0
Nonaccrual [Member] | Combination & Other [Member] | Commercial | Healthcare [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0	0	0
Nonaccrual [Member] | Combination & Other [Member] | Commercial | Other commercial and industrial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0	0	0
Nonaccrual [Member] | Combination & Other [Member] | Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0	0	0
Nonaccrual [Member] | Combination & Other [Member] | Commercial real estate | 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	0	0
Nonaccrual [Member] | Combination & Other [Member] | Commercial real estate | Retail [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0	0	0
Nonaccrual [Member] | Combination & Other [Member] | Commercial real estate | Office [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0	0	0
Nonaccrual [Member] | Combination & Other [Member] | Commercial real estate | Multifamily [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0	0	0
Nonaccrual [Member] | Combination & Other [Member] | Commercial real estate | Industrial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0	0	0
Nonaccrual [Member] | Combination & Other [Member] | Commercial real estate | Other commercial real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	0	0	0
Nonaccrual [Member] | Combination & Other [Member] | Residential mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	612	2,137	1,222	2,660
Nonaccrual [Member] | Combination & Other [Member] | Residential mortgage | Permanent mortgage [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	53	1,183	84	1,244
Nonaccrual [Member] | Combination & Other [Member] | Residential mortgage | Permanent mortgages guaranteed by US government agencies [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	0	625	85	625
Nonaccrual [Member] | Combination & Other [Member] | Residential mortgage | Home equity [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	559	329	1,053	791
Nonaccrual [Member] | Combination & Other [Member] | Personal
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled Debt Restructurings, Recorded Balance Modified During The Period	$ 47	$ 65	$ 51	$ 72

Loans and Allowances for Cred47

Loans and Allowances for Credit Losses, By Aging Category (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016	Jun. 30, 2016
Financing receivable, recorded investment, aging [Abstract]
Current	$ 16,783,348	$ 16,597,641	$ 16,010,465
Nonaccrual	245,439	230,984	247,184
Total	17,183,645	16,989,660	16,406,749
Commercial
Financing receivable, recorded investment, aging [Abstract]
Current	10,438,108	10,205,838	10,167,077
Nonaccrual	197,157	178,953	181,989
Total	10,637,955	10,390,824	10,356,437
Commercial | Energy [Member]
Financing receivable, recorded investment, aging [Abstract]
Current	2,723,248	2,364,890	2,647,678
Nonaccrual	123,992	132,499	168,145
Total	2,847,240	2,497,868	2,818,656
Commercial | Services [Member]
Financing receivable, recorded investment, aging [Abstract]
Current	2,949,562	3,099,605	2,817,217
Nonaccrual	7,754	8,173	9,388
Total	2,958,827	3,108,990	2,830,864
Commercial | Wholesale/retail [Member]
Financing receivable, recorded investment, aging [Abstract]
Current	1,532,986	1,561,650	1,530,110
Nonaccrual	10,620	11,407	2,772
Total	1,543,695	1,576,818	1,532,957
Commercial | Manufacturing [Member]
Financing receivable, recorded investment, aging [Abstract]
Current	536,481	509,662	595,110
Nonaccrual	9,656	4,931	293
Total	546,137	514,975	595,403
Commercial | Healthcare [Member]
Financing receivable, recorded investment, aging [Abstract]
Current	2,196,088	2,201,050	2,050,271
Nonaccrual	24,505	825	875
Total	2,221,518	2,201,916	2,051,146
Commercial | Other commercial and industrial [Member]
Financing receivable, recorded investment, aging [Abstract]
Current	499,743	468,981	526,691
Nonaccrual	20,630	21,118	516
Total	520,538	490,257	527,411
Commercial real estate
Financing receivable, recorded investment, aging [Abstract]
Current	3,684,343	3,803,519	3,571,877
Nonaccrual	3,775	5,521	7,780
Total	3,688,592	3,809,046	3,581,966
Commercial real estate | Residential construction and land development [Member]
Financing receivable, recorded investment, aging [Abstract]
Current	139,070	132,100	153,315
Nonaccrual	2,051	3,433	4,261
Total	141,592	135,533	157,576
Commercial real estate | Retail [Member]
Financing receivable, recorded investment, aging [Abstract]
Current	722,504	761,562	794,154
Nonaccrual	301	326	1,265
Total	722,805	761,888	795,419
Commercial real estate | Office [Member]
Financing receivable, recorded investment, aging [Abstract]
Current	862,577	798,462	768,506
Nonaccrual	396	426	606
Total	862,973	798,888	769,112
Commercial real estate | Multifamily [Member]
Financing receivable, recorded investment, aging [Abstract]
Current	952,370	903,234	784,826
Nonaccrual	10	38	65
Total	952,380	903,272	787,200
Commercial real estate | Industrial [Member]
Financing receivable, recorded investment, aging [Abstract]
Current	693,635	871,673	645,510
Nonaccrual	0	76	76
Total	693,635	871,749	645,586
Commercial real estate | Other commercial real estate [Member]
Financing receivable, recorded investment, aging [Abstract]
Current	314,187	336,488	425,566
Nonaccrual	1,017	1,222	1,507
Total	315,207	337,716	427,073
Residential mortgage
Financing receivable, recorded investment, aging [Abstract]
Current	1,744,045	1,749,473	1,684,900
Nonaccrual	44,235	46,220	57,061
Total	1,939,198	1,949,832	1,880,923
Residential mortgage | Permanent mortgage [Member]
Financing receivable, recorded investment, aging [Abstract]
Current	962,443	979,386	935,857
Nonaccrual	23,415	22,855	27,228
Total	989,040	1,006,820	969,007
Residential mortgage | Permanent mortgages guaranteed by US government agencies [Member]
Financing receivable, recorded investment, aging [Abstract]
Current	36,867	40,594	42,019
Nonaccrual	9,052	11,846	19,741
Total	191,729	199,387	192,732
Residential mortgage | Home equity [Member]
Financing receivable, recorded investment, aging [Abstract]
Current	744,735	729,493	707,024
Nonaccrual	11,768	11,519	10,092
Total	758,429	743,625	719,184
Personal
Financing receivable, recorded investment, aging [Abstract]
Current	916,852	838,811	586,611
Nonaccrual	272	290	354
Total	917,900	839,958	587,423
30 to 59 Days [Member]
Financing receivable, recorded investment, aging [Abstract]
Past Due	24,074	28,603	26,390
30 to 59 Days [Member] | Commercial
Financing receivable, recorded investment, aging [Abstract]
Past Due	1,109	4,968	645
30 to 59 Days [Member] | Commercial | Energy [Member]
Financing receivable, recorded investment, aging [Abstract]
Past Due	0	479	0
30 to 59 Days [Member] | Commercial | Services [Member]
Financing receivable, recorded investment, aging [Abstract]
Past Due	50	191	494
30 to 59 Days [Member] | Commercial | Wholesale/retail [Member]
Financing receivable, recorded investment, aging [Abstract]
Past Due	89	3,761	75
30 to 59 Days [Member] | Commercial | Manufacturing [Member]
Financing receivable, recorded investment, aging [Abstract]
Past Due	0	382	0
30 to 59 Days [Member] | Commercial | Healthcare [Member]
Financing receivable, recorded investment, aging [Abstract]
Past Due	925	0	0
30 to 59 Days [Member] | Commercial | Other commercial and industrial [Member]
Financing receivable, recorded investment, aging [Abstract]
Past Due	45	155	76
30 to 59 Days [Member] | Commercial real estate
Financing receivable, recorded investment, aging [Abstract]
Past Due	474	6	2,309
30 to 59 Days [Member] | Commercial real estate | Residential construction and land development [Member]
Financing receivable, recorded investment, aging [Abstract]
Past Due	471	0	0
30 to 59 Days [Member] | Commercial real estate | Retail [Member]
Financing receivable, recorded investment, aging [Abstract]
Past Due	0	0	0
30 to 59 Days [Member] | Commercial real estate | Office [Member]
Financing receivable, recorded investment, aging [Abstract]
Past Due	0	0	0
30 to 59 Days [Member] | Commercial real estate | Multifamily [Member]
Financing receivable, recorded investment, aging [Abstract]
Past Due	0	0	2,309
30 to 59 Days [Member] | Commercial real estate | Industrial [Member]
Financing receivable, recorded investment, aging [Abstract]
Past Due	0	0	0
30 to 59 Days [Member] | Commercial real estate | Other commercial real estate [Member]
Financing receivable, recorded investment, aging [Abstract]
Past Due	3	6	0
30 to 59 Days [Member] | Residential mortgage
Financing receivable, recorded investment, aging [Abstract]
Past Due	22,004	23,040	23,036
30 to 59 Days [Member] | Residential mortgage | Permanent mortgage [Member]
Financing receivable, recorded investment, aging [Abstract]
Past Due	2,024	3,299	5,798
30 to 59 Days [Member] | Residential mortgage | Permanent mortgages guaranteed by US government agencies [Member]
Financing receivable, recorded investment, aging [Abstract]
Past Due	18,416	17,465	15,349
30 to 59 Days [Member] | Residential mortgage | Home equity [Member]
Financing receivable, recorded investment, aging [Abstract]
Past Due	1,564	2,276	1,889
30 to 59 Days [Member] | Personal
Financing receivable, recorded investment, aging [Abstract]
Past Due	487	589	400
60 to 89 Days [Member]
Financing receivable, recorded investment, aging [Abstract]
Past Due	15,557	16,748	16,057
60 to 89 Days [Member] | Commercial
Financing receivable, recorded investment, aging [Abstract]
Past Due	299	1,065	3,847
60 to 89 Days [Member] | Commercial | Energy [Member]
Financing receivable, recorded investment, aging [Abstract]
Past Due	0	0	0
60 to 89 Days [Member] | Commercial | Services [Member]
Financing receivable, recorded investment, aging [Abstract]
Past Due	180	1,021	3,765
60 to 89 Days [Member] | Commercial | Wholesale/retail [Member]
Financing receivable, recorded investment, aging [Abstract]
Past Due	0	0	0
60 to 89 Days [Member] | Commercial | Manufacturing [Member]
Financing receivable, recorded investment, aging [Abstract]
Past Due	0	0	0
60 to 89 Days [Member] | Commercial | Healthcare [Member]
Financing receivable, recorded investment, aging [Abstract]
Past Due	0	41	0
60 to 89 Days [Member] | Commercial | Other commercial and industrial [Member]
Financing receivable, recorded investment, aging [Abstract]
Past Due	119	3	82
60 to 89 Days [Member] | Commercial real estate
Financing receivable, recorded investment, aging [Abstract]
Past Due	0	0	0
60 to 89 Days [Member] | Commercial real estate | Residential construction and land development [Member]
Financing receivable, recorded investment, aging [Abstract]
Past Due	0	0	0
60 to 89 Days [Member] | Commercial real estate | Retail [Member]
Financing receivable, recorded investment, aging [Abstract]
Past Due	0	0	0
60 to 89 Days [Member] | Commercial real estate | Office [Member]
Financing receivable, recorded investment, aging [Abstract]
Past Due	0	0	0
60 to 89 Days [Member] | Commercial real estate | Multifamily [Member]
Financing receivable, recorded investment, aging [Abstract]
Past Due	0	0	0
60 to 89 Days [Member] | Commercial real estate | Industrial [Member]
Financing receivable, recorded investment, aging [Abstract]
Past Due	0	0	0
60 to 89 Days [Member] | Commercial real estate | Other commercial real estate [Member]
Financing receivable, recorded investment, aging [Abstract]
Past Due	0	0	0
60 to 89 Days [Member] | Residential mortgage
Financing receivable, recorded investment, aging [Abstract]
Past Due	14,969	15,420	12,152
60 to 89 Days [Member] | Residential mortgage | Permanent mortgage [Member]
Financing receivable, recorded investment, aging [Abstract]
Past Due	1,026	1,280	124
60 to 89 Days [Member] | Residential mortgage | Permanent mortgages guaranteed by US government agencies [Member]
Financing receivable, recorded investment, aging [Abstract]
Past Due	13,581	13,803	11,869
60 to 89 Days [Member] | Residential mortgage | Home equity [Member]
Financing receivable, recorded investment, aging [Abstract]
Past Due	362	337	159
60 to 89 Days [Member] | Personal
Financing receivable, recorded investment, aging [Abstract]
Past Due	289	263	58
90 Days or More [Member]
Financing receivable, recorded investment, aging [Abstract]
Past Due	115,227	115,684	106,653
90 Days or More [Member] | Commercial
Financing receivable, recorded investment, aging [Abstract]
Past Due	1,282	0	2,879
90 Days or More [Member] | Commercial | Energy [Member]
Financing receivable, recorded investment, aging [Abstract]
Past Due	0	0	2,833
90 Days or More [Member] | Commercial | Services [Member]
Financing receivable, recorded investment, aging [Abstract]
Past Due	1,281	0	0
90 Days or More [Member] | Commercial | Wholesale/retail [Member]
Financing receivable, recorded investment, aging [Abstract]
Past Due	0	0	0
90 Days or More [Member] | Commercial | Manufacturing [Member]
Financing receivable, recorded investment, aging [Abstract]
Past Due	0	0	0
90 Days or More [Member] | Commercial | Healthcare [Member]
Financing receivable, recorded investment, aging [Abstract]
Past Due	0	0	0
90 Days or More [Member] | Commercial | Other commercial and industrial [Member]
Financing receivable, recorded investment, aging [Abstract]
Past Due	1	0	46
90 Days or More [Member] | Commercial real estate
Financing receivable, recorded investment, aging [Abstract]
Past Due	0	0	0
90 Days or More [Member] | Commercial real estate | Residential construction and land development [Member]
Financing receivable, recorded investment, aging [Abstract]
Past Due	0	0	0
90 Days or More [Member] | Commercial real estate | Retail [Member]
Financing receivable, recorded investment, aging [Abstract]
Past Due	0	0	0
90 Days or More [Member] | Commercial real estate | Office [Member]
Financing receivable, recorded investment, aging [Abstract]
Past Due	0	0	0
90 Days or More [Member] | Commercial real estate | Multifamily [Member]
Financing receivable, recorded investment, aging [Abstract]
Past Due	0	0	0
90 Days or More [Member] | Commercial real estate | Industrial [Member]
Financing receivable, recorded investment, aging [Abstract]
Past Due	0	0	0
90 Days or More [Member] | Commercial real estate | Other commercial real estate [Member]
Financing receivable, recorded investment, aging [Abstract]
Past Due	0	0	0
90 Days or More [Member] | Residential mortgage
Financing receivable, recorded investment, aging [Abstract]
Past Due	113,945	115,679	103,774
90 Days or More [Member] | Residential mortgage | Permanent mortgage [Member]
Financing receivable, recorded investment, aging [Abstract]
Past Due	132	0	0
90 Days or More [Member] | Residential mortgage | Permanent mortgages guaranteed by US government agencies [Member]
Financing receivable, recorded investment, aging [Abstract]
Past Due	113,813	115,679	103,754
90 Days or More [Member] | Residential mortgage | Home equity [Member]
Financing receivable, recorded investment, aging [Abstract]
Past Due	0	0	20
90 Days or More [Member] | Personal
Financing receivable, recorded investment, aging [Abstract]
Past Due	$ 0	$ 5	$ 0

Acquisitions (Details)

Acquisitions (Details) - MBT Bancshares [Member] - USD ($) $ in Thousands	Dec. 01, 2016	Jun. 30, 2017
Business Acquisition [Line Items]
Business Acquisition, Effective Date of Acquisition	Dec. 1, 2016
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net	$ 102,500
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Intangibles		$ 2,000
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Property, Plant, and Equipment		1,500
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Goodwill		$ 526

Mortgage Banking Activities, Co

Mortgage Banking Activities, Components of Loans Held For Sale (Details) - USD ($) $ in Thousands	6 Months Ended		12 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Schedule of Residential Mortgage Loans Held For Sale [Line Items]
Number of days for past due for loan to be considered nonperforming (in days)	90 days	90 days	90 days
Residential mortgage loans held for sale, nonperforming	$ 0	$ 0	$ 0
Credit losses recognized on residential mortgage loans held for sale	0	0	0
Components of Residential Mortgage Loans Held for Sale [Abstract]
Unpaid principal balance	269,772	404,507	286,414
Residential mortgage loans held for sale, Fair value	275,179	417,542	286,971
Total residential mortgage loans held for sale and mortgage loan commitments, net of forward sales contracts	$ 287,259	$ 430,728	$ 301,897
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	60 days
General number of days outstanding for residential mortgage commitments, maximum (in days)	90 days	90 days	90 days
Components of Residential Mortgage Loans Held for Sale [Abstract]
Notional	$ 362,088	$ 965,631	$ 318,359
Derivative, Net fair value	$ 10,993	$ 25,499	$ 9,733
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	60 days
General number of days for delivery for loans, for which the price is set by forward sales contracts, maximum (in days)	90 days	90 days	90 days
Components of Residential Mortgage Loans Held for Sale [Abstract]
Notional	$ 587,595	$ 1,216,966	$ 569,543
Derivative, Net fair value	$ 1,087	$ (12,313)	$ 5,193

Mortgage Banking Activities Mor

Mortgage Banking Activities Mortgage Banking Activities, Mortgage Banking Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Mortgage Banking Revenue [Abstract]
Net realized gains on sale of mortgage loans	$ 11,787	$ 15,865	$ 20,402	$ 24,314
Net change in unrealized gain on mortgage loans held for sale	985	3,884	4,827	7,167
Net change in the fair value of mortgage loan commitments	(3,274)	5,329	1,260	17,365
Net change in the fair value of forward sales contracts	4,342	(5,992)	(4,106)	(13,113)
Total production revenue	13,840	19,086	22,383	35,733
Servicing revenue	16,436	15,798	33,084	31,251
Total mortgage banking revenue	$ 30,276	$ 34,884	$ 55,467	$ 66,984

Mortgage Banking Activities, Mo

Mortgage Banking Activities, Mortgage Servicing Rights (Details)	3 Months Ended			6 Months Ended
	Jun. 30, 2017USD ($)	Dec. 31, 2016USD ($)	Jun. 30, 2016USD ($)	Jun. 30, 2017USD ($)	Jun. 30, 2016USD ($)
Summary of Mortgage Servicing Rights [Abstract]
Number of residential mortgage loans serviced for others	138,335	139,340	137,210	138,335	137,210
Outstanding principal balance of residential mortgage loans serviced for others	$ 22,095,232,000	$ 21,997,568,000	$ 21,178,387,000	$ 22,095,232,000	$ 21,178,387,000
Weighted average interest rate	3.95%	3.97%	4.06%	3.95%	4.06%
Remaining term (in months)	299 months	301 months	301 months
Servicing Asset at Fair Value, Amount [Roll Forward]
Beginning balance	$ 249,403,000		$ 196,055,000	$ 247,073,000	$ 218,605,000
Additions, net	11,078,000		20,773,000	19,514,000	34,355,000
Change in fair value due to scheduled payments and full-balance payoffs	(8,299,000)		(9,798,000)	(16,261,000)	(17,942,000)
Change in fair value due to market assumption changes	(6,943,000)		(16,283,000)	(5,087,000)	(44,271,000)
Ending balance	$ 245,239,000	$ 247,073,000	$ 190,747,000	$ 245,239,000	$ 190,747,000
Servicing Assets at Fair Value, Assumptions Used to Estimate Fair Value [Abstract]
Discount rate - risk-free rate plus a market premium (in hundredths)	9.84%	10.08%	10.09%
Prepayment rate - based upon loan interest rate, original term and loan type, minimum	8.61%	8.98%	9.26%
Prepayment rate - based upon loan interest rate, original term and loan type, maximum	15.91%	16.91%	42.77%
Loan servicing costs - annually per loan based upon loan type, performing, minimum (in dollars per loan)	$ 65	$ 63	$ 63
Loan servicing costs - annually per loan based upon loan type, performing, maximum (in dollars per loan)	120	120	120
Loan servicing costs - annually per loan based upon loan type, delinquent, minimum (in dollars per loan)	150	150	150
Loan servicing costs - annually per loan based upon loan type, delinquent, maximum (in dollars per loan)	500	500	500
Loan servicing costs - annually per loan based upon loan type, foreclosure, minimum (in dollars per loan)	1,000	650	650
Loan servicing costs - annually per loan based upon loan type, foreclosure, maximum (in dollars per loan)	$ 4,250	$ 4,250	$ 4,250
Escrow earnings rate - indexed to rates paid on deposit accounts with comparable average life (in hundredths)	1.95%	1.98%	0.99%
Primary secondary mortgage rate spread (in basis points)	105	105	115	105	115
Purchased [Member]
Servicing Asset at Fair Value, Amount [Roll Forward]
Beginning balance	$ 8,316,000		$ 5,949,000	$ 8,909,000	$ 9,911,000
Additions, net	0		0	0	0
Change in fair value due to scheduled payments and full-balance payoffs	(464,000)		(730,000)	(973,000)	(1,356,000)
Change in fair value due to market assumption changes	143,000		(1,152,000)	59,000	(4,488,000)
Ending balance	7,995,000	$ 8,909,000	4,067,000	7,995,000	4,067,000
Originated [Member]
Servicing Asset at Fair Value, Amount [Roll Forward]
Beginning balance	241,087,000		190,106,000	238,164,000	208,694,000
Additions, net	11,078,000		20,773,000	19,514,000	34,355,000
Change in fair value due to scheduled payments and full-balance payoffs	(7,835,000)		(9,068,000)	(15,288,000)	(16,586,000)
Change in fair value due to market assumption changes	(7,086,000)		(15,131,000)	(5,146,000)	(39,783,000)
Ending balance	$ 237,244,000	$ 238,164,000	$ 186,680,000	$ 237,244,000	$ 186,680,000

Mortgage Banking Activities M52

Mortgage Banking Activities Mortgage Banking Activities, Loans Serviced for Others (Details) $ in Thousands	Jun. 30, 2017USD ($)
Financing Receivable, Recorded Investment, Aging [Abstract]
Current	$ 21,685,252
30 to 59 Days Past Due	269,744
60 to 89 Days Past Due	71,240
90 Days or More Past Due	68,996
Total	22,095,232
Federal Home Loan Mortgage Corporation Certificates and Obligations (FHLMC) [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Current	8,083,330
30 to 59 Days Past Due	48,659
60 to 89 Days Past Due	12,294
90 Days or More Past Due	27,338
Total	8,171,621
Federal National Mortgage Association Certificates and Obligations (FNMA) [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Current	6,756,211
30 to 59 Days Past Due	46,918
60 to 89 Days Past Due	10,679
90 Days or More Past Due	23,981
Total	6,837,789
Government National Mortgage Association Certificates and Obligations (GNMA) [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Current	6,331,439
30 to 59 Days Past Due	170,889
60 to 89 Days Past Due	47,335
90 Days or More Past Due	16,082
Total	6,565,745
Other Investor Loans [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Current	514,272
30 to 59 Days Past Due	3,278
60 to 89 Days Past Due	932
90 Days or More Past Due	1,595
Total	$ 520,077

Mortgage Banking Activities, Lo

Mortgage Banking Activities, Loans Sold With Recourse (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017USD ($)	Jun. 30, 2016USD ($)	Jun. 30, 2017USD ($)	Jun. 30, 2016USD ($)
Residential Mortgage Loan Repurchase and Servicing Losses [Abstract]
Number of mortgages purchased under repurchase agreement with government sponsored entities.	5
Purchase price of loans purchased under repurchase agreement with government sponsored entities	$ 1,315
Number of loans sold under standard representations and warranties indemnified	4
Number of unresolved deficiency requests	206	211	206	211
Aggregate outstanding principal balance subject to unresolved deficiency requests	$ 13,370	$ 15,920	$ 13,370	$ 15,920
Unpaid principal balance subject to indemnification by the Company	5,074	5,519	5,074	5,519
Activity in accrual for mortgage losses [Rollforward]
Beginning balance	2,587	2,974	2,788	3,359
Provision for losses	(895)	368	(1,094)	250
Charge-offs, net	(45)	(89)	(47)	(356)
Ending balance	$ 1,647	$ 3,253	$ 1,647	$ 3,253

Commitments and Contingent Li54

Commitments and Contingent Liabilities (Details)	6 Months Ended	12 Months Ended
	Jun. 30, 2017USD ($)shares	Dec. 31, 2016USD ($)
BOKF Equity, LLC [Member]
Litigation Settlement [Abstract]
Number of Private Equity Funds of which the Entity is a General Partner	2
Contingent Obligations For Additional Investments in Private Equity Funds	$ 4,000,000
Cavanal Hill Funds [Member]
Litigation Settlement [Abstract]
The Net Asset Value of Units in Mutual Funds (per unit)	1
Settled Litigation [Member] | Deposit Account Posting Class Action [Member]
Litigation Settlement [Abstract]
Litigation Settlement, Amount		$ 7,800,000
Judicial Ruling [Member] | Misuse of Revenues Pledged to Municipal Bonds [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
Pending Litigation [Member] | Misuse of Revenues Pledged to Municipal Bonds [Member]
Litigation Settlement [Abstract]
Loss Contingency, Number of Plaintiffs	2
Pending Litigation [Member] | Bank Participation in Fraudulent Sale of Securities by Principals [Member]
Litigation Settlement [Abstract]
Loss Contingency, Number of Plaintiffs	19
Pending Litigation [Member] | Purchase of facilities from principals subject to SEC New Jersey proceedings [Member]
Litigation Settlement [Abstract]
Outstanding principal, accrued interest and other amounts required by bond documents	$ 60,000,000
Number of individuals who purchased facilities from the principals subject to SEC New Jersey proceedings	2
Number of principals in SEC New Jersey proceedings	2
Pending Litigation [Member] | Ownership of deposit accounts [Member]
Litigation Settlement [Abstract]
Loss Contingency, Number of Plaintiffs	2
Amount paid by the bank from creditor accounts to judgment creditor	$ 4,200,000
Loss Contingency, Damages Sought, Value	$ 7,000,000
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

Commitments and Contingent Li55

Commitments and Contingent Liabilities Variable Interest Entities (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016	Jun. 30, 2016
Loans Receivable [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net	$ 10,000	$ 10,000	$ 10,000
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets and Liabilities, Net	59,744	44,488	32,679
Loans Receivable [Member] | Private equity funds [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net	0	0	0
Loans Receivable [Member] | Tax credit entities [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net	10,000	10,000	10,000
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets and Liabilities, Net	59,744	44,488	32,679
Loans Receivable [Member] | Other [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net	0	0	0
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets and Liabilities, Net	0	0	0
Other Assets [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net	44,073	58,725	67,751
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets and Liabilities, Net	181,680	175,390	125,577
Other Assets [Member] | Private equity funds [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net	16,905	17,357	20,469
Other Assets [Member] | Tax credit entities [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net	11,274	11,585	11,895
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets and Liabilities, Net	148,525	143,715	102,138
Other Assets [Member] | Other [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net	15,894	29,783	35,387
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets and Liabilities, Net	33,155	31,675	23,439
Other Liabilities [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net	1,621	3,189	2,004
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets and Liabilities, Net	77,502	78,357	44,720
Other Liabilities [Member] | Private equity funds [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net	0	0	0
Other Liabilities [Member] | Tax credit entities [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net	0	0	0
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets and Liabilities, Net	63,822	63,329	30,953
Other Liabilities [Member] | Other [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net	1,621	3,189	2,004
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets and Liabilities, Net	13,680	15,028	13,767
Other borrowings [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net	11,842	12,056	13,236
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets and Liabilities, Net	0	0	0
Other borrowings [Member] | Private equity funds [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net	0	0	0
Other borrowings [Member] | Tax credit entities [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net	10,964	10,964	10,964
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets and Liabilities, Net	0	0	0
Other borrowings [Member] | Other [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net	878	1,092	2,272
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets and Liabilities, Net	0	0	0
Non-Controlling Interests [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net	27,076	31,503	33,905
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets and Liabilities, Net	0	0	0
Non-Controlling Interests [Member] | Private equity funds [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net	14,199	13,237	16,316
Non-Controlling Interests [Member] | Tax credit entities [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net	10,000	10,000	10,000
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets and Liabilities, Net	0	0	0
Non-Controlling Interests [Member] | Other [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net	2,877	8,266	7,589
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets and Liabilities, Net	$ 0	$ 0	$ 0

Shareholders' Equity (Details)

Shareholders' Equity (Details) - USD ($) $ / shares in Units, $ in Thousands		Jul. 25, 2017	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017		Jun. 30, 2016
Dividends declared (in dollars per share)			$ 0.44	$ 0.43	$ 0.88		$ 0.86
Schedule of Accumulated Other Income (Loss) [Abstract]
Balance, Beginning of Period					$ (10,967)		$ 21,587
Net change in unrealized gain (loss)			$ 21,958	$ 45,475	33,369		166,566
Reclassification adjustments included in earnings:
Interest revenue, Investment securities, Taxable securities			0	(43)	0		(112)
Gain on available for sale securities, net			(380)	(5,326)	(2,429)		(9,290)
Other comprehensive income (loss), before income taxes			21,578	40,106	30,940		157,164
Federal and state income taxes			8,393	15,583	12,009	[1]	61,119	[1]
Other comprehensive income (loss), net of income taxes			13,185	24,523	18,931		96,045
Balance, End of Period			7,964	117,632	7,964		117,632
Accumulated Net Unrealized Gain (Loss) on Available for Sale Securities [Member]
Schedule of Accumulated Other Income (Loss) [Abstract]
Balance, Beginning of Period					(9,087)		23,284
Net change in unrealized gain (loss)					33,369		166,566
Reclassification adjustments included in earnings:
Interest revenue, Investment securities, Taxable securities							0
Gain on available for sale securities, net					(2,429)		(9,290)
Other comprehensive income (loss), before income taxes					30,940		157,276
Federal and state income taxes	[1]				12,009		61,163
Other comprehensive income (loss), net of income taxes					18,931		96,113
Balance, End of Period			9,844	119,397	9,844		119,397
Accumulated Unrealized Gain on Investment Securities Transferred from AFS [Member]
Schedule of Accumulated Other Income (Loss) [Abstract]
Balance, Beginning of Period					0		68
Net change in unrealized gain (loss)					0		0
Reclassification adjustments included in earnings:
Interest revenue, Investment securities, Taxable securities							(112)
Gain on available for sale securities, net					0		0
Other comprehensive income (loss), before income taxes					0		(112)
Federal and state income taxes	[1]						(44)
Other comprehensive income (loss), net of income taxes					0		(68)
Balance, End of Period			0	0	0		0
Accumulated Unrealized Gain (Loss) on Employee Benefit Plans [Member]
Schedule of Accumulated Other Income (Loss) [Abstract]
Balance, Beginning of Period					(1,880)		(1,765)
Net change in unrealized gain (loss)					0		0
Reclassification adjustments included in earnings:
Interest revenue, Investment securities, Taxable securities							0
Gain on available for sale securities, net					0		0
Other comprehensive income (loss), before income taxes					0		0
Federal and state income taxes	[1]				0		0
Other comprehensive income (loss), net of income taxes					0		0
Balance, End of Period			(1,880)	$ (1,765)	(1,880)		$ (1,765)
Subsequent Event [Member]
Dividends Payable, Date Declared		Jul. 25, 2017
Dividends declared (in dollars per share)		$ 0.44
Dividends Payable, Date to be Paid		Aug. 25, 2017
Dividends Payable, Date of Record		Aug. 11, 2017
Perpetual Preferred, Equity Securities and Mutual Funds [Member] | Accumulated Net Unrealized Gain (Loss) on Available for Sale Securities [Member]
Reclassification adjustments included in earnings:
Balance, End of Period			$ 3,200		$ 3,200
[1]	Calculated using a 39 percent effective tax rate.

Earnings Per Share (Details)

Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Numerator: [Abstract]
Net income attributable to BOK Financial Corp. shareholders	$ 88,147	$ 65,801	$ 176,503	$ 108,365
Less: Earnings allocated to participating securities	926	821	1,929	1,359
Numerator for basic earnings per share – income available to common shareholders	87,221	64,980	174,574	107,006
Effect of reallocating undistributed earnings of participating securities	1	0	1	0
Numerator for diluted earnings per share – income available to common shareholders	$ 87,222	$ 64,980	$ 174,575	$ 107,006
Denominator: [Abstract]
Weighted average shares outstanding (in shares)	65,416,274	66,069,392	65,436,909	66,100,279
Less: Participating securities included in weighted average shares (in shares)	686,522	823,505	714,165	829,065
Denominator for basic earnings per common share (in shares)	64,729,752	65,245,887	64,722,744	65,271,214
Dilutive effect of employee stock compensation plans (in shares)	63,382	57,039	65,578	45,963
Denominator for diluted earnings per common share (in shares)	64,793,134	65,302,926	64,788,322	65,317,177
Basic earnings per share (per share)	$ 1.35	$ 1	$ 2.70	$ 1.64
Diluted earnings per share (per share)	$ 1.35	$ 1	$ 2.69	$ 1.64
Excludes employee stock options with exercise prices greater than current market price.	0	0	0	145,247,000

Reportable Segments (Details)

Reportable Segments (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Segment Reporting Information [Line Items]
NIR (expense) from external sources	$ 205,204	$ 182,612	$ 406,386	$ 365,184
NIR (expense) from internal sources	0	0	0	0
Net interest revenue	205,204	182,612	406,386	365,184
Provision for credit losses	0	20,000	0	55,000
Net interest revenue after provision for credit losses	205,204	162,612	406,386	310,184
Other operating revenue	182,252	185,542	352,548	342,956
Other operating expense	250,885	251,385	495,596	493,955
Net direct contribution	136,571	96,769	263,338	159,185
Gain (loss) on financial instruments, net	0	0	0	0
Change in fair value of mortgage servicing rights	0	0	0	0
Gain (loss) on repossessed assets, net	0	0	0	0
Corporate expense allocations	0	0	0	0
Net income before taxes	136,571	96,769	263,338	159,185
Federal and state income taxes	47,705	30,497	85,808	51,925
Net income	88,866	66,272	177,530	107,260
Net income (loss) attributable to non-controlling interests	719	471	1,027	(1,105)
Net income attributable to BOK Financial Corp. shareholders	88,147	65,801	176,503	108,365
Average assets	32,368,571	31,986,042	32,660,160	31,747,257
Operating Segments [Member] | Commercial [Member]
Segment Reporting Information [Line Items]
NIR (expense) from external sources	144,164	118,480	278,868	235,116
NIR (expense) from internal sources	(20,347)	(14,575)	(37,140)	(29,208)
Net interest revenue	123,817	103,905	241,728	205,908
Provision for credit losses	1,228	6,852	(234)	28,423
Net interest revenue after provision for credit losses	122,589	97,053	241,962	177,485
Other operating revenue	55,778	51,497	102,048	96,605
Other operating expense	59,128	52,594	111,565	108,663
Net direct contribution	119,239	95,956	232,445	165,427
Gain (loss) on financial instruments, net	3	0	41	0
Change in fair value of mortgage servicing rights	0	0	0	0
Gain (loss) on repossessed assets, net	1,403	(598)	1,398	(680)
Corporate expense allocations	8,862	8,883	17,493	17,627
Net income before taxes	111,783	86,475	216,391	147,120
Federal and state income taxes	43,484	33,639	84,176	57,230
Net income	68,299	52,836	132,215	89,890
Net income (loss) attributable to non-controlling interests	0	0	0	0
Net income attributable to BOK Financial Corp. shareholders	68,299	52,836	132,215	89,890
Average assets	17,596,273	16,973,663	17,517,960	16,971,339
Operating Segments [Member] | Consumer [Member]
Segment Reporting Information [Line Items]
NIR (expense) from external sources	23,503	22,349	44,632	43,799
NIR (expense) from internal sources	11,837	8,876	22,789	18,229
Net interest revenue	35,340	31,225	67,421	62,028
Provision for credit losses	926	1,318	2,198	3,020
Net interest revenue after provision for credit losses	34,414	29,907	65,223	59,008
Other operating revenue	52,102	57,440	99,408	111,469
Other operating expense	55,709	62,806	109,242	118,524
Net direct contribution	30,807	24,541	55,389	51,953
Gain (loss) on financial instruments, net	5,224	15,045	3,557	31,626
Change in fair value of mortgage servicing rights	(6,943)	(16,283)	(5,087)	(44,271)
Gain (loss) on repossessed assets, net	98	252	(39)	406
Corporate expense allocations	17,039	16,630	33,908	32,608
Net income before taxes	12,147	6,925	19,912	7,106
Federal and state income taxes	4,725	2,694	7,746	2,764
Net income	7,422	4,231	12,166	4,342
Net income (loss) attributable to non-controlling interests	0	0	0	0
Net income attributable to BOK Financial Corp. shareholders	7,422	4,231	12,166	4,342
Average assets	8,845,398	8,774,881	8,747,524	8,731,085
Operating Segments [Member] | Wealth Management [Member]
Segment Reporting Information [Line Items]
NIR (expense) from external sources	10,474	6,271	21,960	12,349
NIR (expense) from internal sources	10,325	7,193	19,181	14,857
Net interest revenue	20,799	13,464	41,141	27,206
Provision for credit losses	(93)	(239)	(53)	(390)
Net interest revenue after provision for credit losses	20,892	13,703	41,194	27,596
Other operating revenue	75,569	75,772	149,727	144,518
Other operating expense	60,615	61,414	121,025	122,098
Net direct contribution	35,846	28,061	69,896	50,016
Gain (loss) on financial instruments, net	0	0	0	0
Change in fair value of mortgage servicing rights	0	0	0	0
Gain (loss) on repossessed assets, net	0	0	0	0
Corporate expense allocations	9,947	10,417	20,619	20,952
Net income before taxes	25,899	17,644	49,277	29,064
Federal and state income taxes	10,075	6,864	19,169	11,306
Net income	15,824	10,780	30,108	17,758
Net income (loss) attributable to non-controlling interests	0	0	0	0
Net income attributable to BOK Financial Corp. shareholders	15,824	10,780	30,108	17,758
Average assets	6,763,093	5,765,390	6,960,872	5,665,218
Funds Management and Other [Member]
Segment Reporting Information [Line Items]
NIR (expense) from external sources	27,063	35,512	60,926	73,920
NIR (expense) from internal sources	(1,815)	(1,494)	(4,830)	(3,878)
Net interest revenue	25,248	34,018	56,096	70,042
Provision for credit losses	(2,061)	12,069	(1,911)	23,947
Net interest revenue after provision for credit losses	27,309	21,949	58,007	46,095
Other operating revenue	(1,197)	833	1,365	(9,636)
Other operating expense	75,433	74,571	153,764	144,670
Net direct contribution	(49,321)	(51,789)	(94,392)	(108,211)
Gain (loss) on financial instruments, net	(5,227)	(15,045)	(3,598)	(31,626)
Change in fair value of mortgage servicing rights	6,943	16,283	5,087	44,271
Gain (loss) on repossessed assets, net	(1,501)	346	(1,359)	274
Corporate expense allocations	(35,848)	(35,930)	(72,020)	(71,187)
Net income before taxes	(13,258)	(14,275)	(22,242)	(24,105)
Federal and state income taxes	(10,579)	(12,700)	(25,283)	(19,375)
Net income	(2,679)	(1,575)	3,041	(4,730)
Net income (loss) attributable to non-controlling interests	719	471	1,027	(1,105)
Net income attributable to BOK Financial Corp. shareholders	(3,398)	(2,046)	2,014	(3,625)
Average assets	$ (836,193)	$ 472,108	$ (566,196)	$ 379,615

Fair Value Measurements, Fair V

Fair Value Measurements, Fair Value Of Financial Instruments as Measured On a Recurring Basis (Details) - USD ($) $ in Thousands	Jun. 30, 2017		Mar. 31, 2017	Dec. 31, 2016		Jun. 30, 2016		Mar. 31, 2016	Dec. 31, 2015
Assets: [Abstract]
Trading securities	$ 441,414			$ 337,628		$ 211,622
Available for sale securities	8,341,041			8,676,829		8,830,689
Fair value option securities	445,169			77,046		263,265
Mortgage servicing rights	245,239		$ 249,403	247,073		190,747		$ 196,055	$ 218,605
Derviative contracts, net of cash collateral, Assets, Fair value	280,289			689,872		883,673
Liabilities: [Abstract]
Derivative contracts, net of cash collateral, Liabilities, Fair Value	285,819			664,531		719,159
U.S. government agency debentures
Assets: [Abstract]
Trading securities	20,954			6,234		18,909
U.S. government agency residential mortgage-backed securities
Assets: [Abstract]
Trading securities	365,171			310,067		122,306
Available for sale securities	5,382,377			5,460,386		5,700,268
Fair value option securities	445,169			77,046		237,959
Municipal and other tax-exempt securities
Assets: [Abstract]
Trading securities	45,444			14,427		52,721
Available for sale securities	32,765			40,993		50,262
Other trading securities
Assets: [Abstract]
Trading securities	9,845			6,900		17,686
U.S. Treasury
Assets: [Abstract]
Available for sale securities	998			999		1,004
Fair value option securities	0			0		25,306
Privately issued residential mortgage-backed securities
Assets: [Abstract]
Available for sale securities	103,383			115,535		126,313
Commercial mortgage-backed securities guaranteed by U.S. government agencies
Assets: [Abstract]
Available for sale securities	2,782,070			3,017,933		2,911,946
Other debt securities
Assets: [Abstract]
Available for sale securities	4,152			4,152		4,151
Perpetual preferred stock
Assets: [Abstract]
Available for sale securities	16,568			18,474		17,931
Equity securities and mutual funds
Assets: [Abstract]
Available for sale securities	18,728			18,357		18,814
Fair Value, Measurements, Recurring [Member]
Assets: [Abstract]
Trading securities	441,414			337,628		211,622
Available for sale securities	8,341,041			8,676,829		8,830,689
Fair value option securities						263,265
Residential mortgage loans held for sale	287,259			301,897		430,728
Mortgage servicing rights	245,239	[1]		247,073	[2]	190,747	[3]
Derviative contracts, net of cash collateral, Assets, Fair value	280,289	[4]		689,872	[5]	883,673	[6]
Liabilities: [Abstract]
Derivative contracts, net of cash collateral, Liabilities, Fair Value	285,819	[4]		664,531	[5]	719,159	[6]
Fair Value, Measurements, Recurring [Member] | U.S. government agency debentures
Assets: [Abstract]
Trading securities	20,954			6,234		18,909
Fair Value, Measurements, Recurring [Member] | U.S. government agency residential mortgage-backed securities
Assets: [Abstract]
Trading securities	365,171			310,067		122,306
Available for sale securities	5,382,377			5,460,386		5,700,268
Fair value option securities	445,169			77,046		237,959
Fair Value, Measurements, Recurring [Member] | Municipal and other tax-exempt securities
Assets: [Abstract]
Trading securities	45,444			14,427		52,721
Available for sale securities	32,765			40,993		50,262
Fair Value, Measurements, Recurring [Member] | Other trading securities
Assets: [Abstract]
Trading securities	9,845			6,900		17,686
Fair Value, Measurements, Recurring [Member] | U.S. Treasury
Assets: [Abstract]
Available for sale securities	998			999		1,004
Fair value option securities						25,306
Fair Value, Measurements, Recurring [Member] | Privately issued residential mortgage-backed securities
Assets: [Abstract]
Available for sale securities	103,383			115,535		126,313
Fair Value, Measurements, Recurring [Member] | Commercial mortgage-backed securities guaranteed by U.S. government agencies
Assets: [Abstract]
Available for sale securities	2,782,070			3,017,933		2,911,946
Fair Value, Measurements, Recurring [Member] | Other debt securities
Assets: [Abstract]
Available for sale securities	4,152			4,152		4,151
Fair Value, Measurements, Recurring [Member] | Perpetual preferred stock
Assets: [Abstract]
Available for sale securities	16,568			18,474		17,931
Fair Value, Measurements, Recurring [Member] | Equity securities and mutual funds
Assets: [Abstract]
Available for sale securities	18,728			18,357		18,814
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Assets: [Abstract]
Trading securities	0			0		0
Available for sale securities	4,514			4,494		4,789
Fair value option securities						25,306
Residential mortgage loans held for sale	0			0		0
Mortgage servicing rights	0	[1]		0	[2]	0	[3]
Derviative contracts, net of cash collateral, Assets, Fair value	20,213	[4]		7,541	[5]	7,246	[6]
Liabilities: [Abstract]
Derivative contracts, net of cash collateral, Liabilities, Fair Value	5,919	[4]		6,972	[5]	4,808	[6]
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | U.S. government agency debentures
Assets: [Abstract]
Trading securities	0			0		0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | U.S. government agency residential mortgage-backed securities
Assets: [Abstract]
Trading securities	0			0		0
Available for sale securities	0			0		0
Fair value option securities	0			0		0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Municipal and other tax-exempt securities
Assets: [Abstract]
Trading securities	0			0		0
Available for sale securities	0			0		0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Other trading securities
Assets: [Abstract]
Trading securities	0			0		0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | U.S. Treasury
Assets: [Abstract]
Available for sale securities	998			999		1,004
Fair value option securities						25,306
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Privately issued residential mortgage-backed securities
Assets: [Abstract]
Available for sale securities	0			0		0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Commercial mortgage-backed securities guaranteed by U.S. government agencies
Assets: [Abstract]
Available for sale securities	0			0		0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Other debt securities
Assets: [Abstract]
Available for sale securities	0			0		0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Perpetual preferred stock
Assets: [Abstract]
Available for sale securities	0			0		0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Equity securities and mutual funds
Assets: [Abstract]
Available for sale securities	3,516			3,495		3,785
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Assets: [Abstract]
Trading securities	441,414			337,628		211,622
Available for sale securities	8,327,720			8,662,394		8,812,149
Fair value option securities						237,959
Residential mortgage loans held for sale	274,524			290,280		420,979
Mortgage servicing rights	0	[1]		0	[2]	0	[3]
Derviative contracts, net of cash collateral, Assets, Fair value	260,076	[4]		682,331	[5]	876,427	[6]
Liabilities: [Abstract]
Derivative contracts, net of cash collateral, Liabilities, Fair Value	279,900	[4]		657,559	[5]	714,351	[6]
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | U.S. government agency debentures
Assets: [Abstract]
Trading securities	20,954			6,234		18,909
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | U.S. government agency residential mortgage-backed securities
Assets: [Abstract]
Trading securities	365,171			310,067		122,306
Available for sale securities	5,382,377			5,460,386		5,700,268
Fair value option securities	445,169			77,046		237,959
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Municipal and other tax-exempt securities
Assets: [Abstract]
Trading securities	45,444			14,427		52,721
Available for sale securities	28,110			35,204		40,662
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Other trading securities
Assets: [Abstract]
Trading securities	9,845			6,900		17,686
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | U.S. Treasury
Assets: [Abstract]
Available for sale securities	0			0		0
Fair value option securities						0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Privately issued residential mortgage-backed securities
Assets: [Abstract]
Available for sale securities	103,383			115,535		126,313
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Commercial mortgage-backed securities guaranteed by U.S. government agencies
Assets: [Abstract]
Available for sale securities	2,782,070			3,017,933		2,911,946
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Other debt securities
Assets: [Abstract]
Available for sale securities	0			0		0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Perpetual preferred stock
Assets: [Abstract]
Available for sale securities	16,568			18,474		17,931
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Equity securities and mutual funds
Assets: [Abstract]
Available for sale securities	15,212			14,862		15,029
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Assets: [Abstract]
Trading securities	0			0		0
Available for sale securities	8,807			9,941		13,751
Fair value option securities						0
Residential mortgage loans held for sale	12,735			11,617		9,749
Mortgage servicing rights	245,239	[1]		247,073	[2]	190,747	[3]
Derviative contracts, net of cash collateral, Assets, Fair value	0	[4]		0	[5]	0	[6]
Liabilities: [Abstract]
Derivative contracts, net of cash collateral, Liabilities, Fair Value	0	[4]		0	[5]	0	[6]
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | U.S. government agency debentures
Assets: [Abstract]
Trading securities	0			0		0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | U.S. government agency residential mortgage-backed securities
Assets: [Abstract]
Trading securities	0			0		0
Available for sale securities	0			0		0
Fair value option securities	0			0		0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Municipal and other tax-exempt securities
Assets: [Abstract]
Trading securities	0			0		0
Available for sale securities	4,655			5,789		9,600
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Other trading securities
Assets: [Abstract]
Trading securities	0			0		0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | U.S. Treasury
Assets: [Abstract]
Available for sale securities	0			0		0
Fair value option securities						0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Privately issued residential mortgage-backed securities
Assets: [Abstract]
Available for sale securities	0			0		0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Commercial mortgage-backed securities guaranteed by U.S. government agencies
Assets: [Abstract]
Available for sale securities	0			0		0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Other debt securities
Assets: [Abstract]
Available for sale securities	4,152			4,152		4,151
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Perpetual preferred stock
Assets: [Abstract]
Available for sale securities	0			0		0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Equity securities and mutual funds
Assets: [Abstract]
Available for sale securities	$ 0			$ 0		$ 0
[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 6, Mortgage Banking Activities.
[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 6, 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 6, Mortgage Banking Activities.
[4]	See Note 3 for detail of fair value of derivative contracts by contract type. Derivative contracts in asset positions that were valued based on quoted prices in active markets for identical instruments (Level 1) are primarily exchange-traded energy and interest rate derivative contacts. Derivative contacts in liability positions that were valued using quoted prices in active markets for identical instruments are exchange-traded interest rate 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 based on quoted prices in active markets for identical instruments (Level 1) are exchange-traded interest-rate and energy derivative contacts, net of cash margin. Derivative contracts in liability positions 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.
[6]	See Note 3 for detail of fair value of derivative contracts by contract type. Derivative contracts based on quoted prices in active markets for identical instruments (Level 1) are exchange-traded energy and agricultural derivative contacts, net of cash margin. Derivative contracts in liability positions that were valued using quoted prices in active markets for identical instruments (Level 1) are exchange-traded interest rate and energy derivative contracts, net 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	3 Months Ended				6 Months Ended
	Jun. 30, 2017		Jun. 30, 2016		Jun. 30, 2017		Jun. 30, 2016
Available-for-sale securities [Member] | Municipal and other tax-exempt securities
Fair Value Assets Measured on Recurring Basis Unobservable Reconciliation [Roll Forward]
Balance, beginning of period	$ 5,722		$ 9,614		$ 5,789		$ 9,610
Transfer to Level 3 from Level 2	0	[1]	0	[2]	0	[1]	0	[2]
Purchases	0		0		0		0
Proceeds from sales	0		0		0		0
Redemptions and distributions	(1,100)		0		(1,100)		0
Other comprehensive income (loss)	33		(14)		(34)		(10)
Balance, end of period	4,655		9,600		4,655		9,600
Available-for-sale securities [Member] | Municipal and other tax-exempt securities | Mortgage banking revenue [Member]
Fair Value Assets Measured on Recurring Basis Unobservable Reconciliation [Roll Forward]
Gain (loss) recognized in earnings	0		0		0		0
Available-for-sale securities [Member] | Other debt securities
Fair Value Assets Measured on Recurring Basis Unobservable Reconciliation [Roll Forward]
Balance, beginning of period	4,153		4,151		4,152		4,151
Transfer to Level 3 from Level 2	0	[1]	0	[2]	0	[1]	0	[2]
Purchases	0		0		0		0
Proceeds from sales	0		0		0		0
Redemptions and distributions	0		0		0		0
Other comprehensive income (loss)	(1)		0		0		0
Balance, end of period	4,152		4,151		4,152		4,151
Available-for-sale securities [Member] | Other debt securities | Mortgage banking revenue [Member]
Fair Value Assets Measured on Recurring Basis Unobservable Reconciliation [Roll Forward]
Gain (loss) recognized in earnings	0		0		0		0
Residential mortgage loans held for sale [Member]
Fair Value Assets Measured on Recurring Basis Unobservable Reconciliation [Roll Forward]
Balance, beginning of period	12,679		8,099		11,617		7,874
Transfer to Level 3 from Level 2	853	[1]	3,080	[2]	2,740	[1]	3,540	[2]
Purchases	0		0		0		0
Proceeds from sales	(1,030)		(1,249)		(1,702)		(1,362)
Redemptions and distributions	0		0		0		0
Other comprehensive income (loss)	0		0		0		0
Balance, end of period	12,735		9,749		12,735		9,749
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	$ 233		$ (181)		$ 80		$ (303)
[1]	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.
[2]	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	6 Months Ended				12 Months Ended
	Jun. 30, 2017		Jun. 30, 2016		Dec. 31, 2016
Available-for-sale securities [Member] | Municipal and other tax-exempt securities
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Inputs, Asset, Par Value	$ 5,095		$ 10,370		$ 6,195
Fair Value Inputs, Asset, Amortized Cost/Unpaid Principal Balance	5,067		10,312		6,163
Fair Value Inputs, Asset, Fair Value	$ 4,655		$ 9,600		$ 5,789
Fair Value Measurements, Valuation Techniques	Discounted cash flows	[1]	Discounted cash flows	[2]	Discounted cash flows	[3]
Fair Value Measurements, Significant Unobservable Input	Interest rate spread		Interest rate spread		Interest rate spread
Fair Value Inputs, Assets, Discount Rate, Minimum	5.98%	[4]	5.34%	[5]	5.91%	[6]
Fair Value Inputs, Assets, Discount Rate, Maximum	5.98%	[4]	5.64%	[5]	6.21%	[6]
Fair Value Inputs, Assets, Discount Rate, Weighted Average	5.98%	[4]	5.60%	[5]	6.16%	[6]
Fair Value Inputs, Assets, Fair Value As Percentage of Par Value, Minimum	90.00%	[7]	90.00%	[8]	90.00%	[9]
Fair Value Inputs, Assets, Fair Value As Percentage of Par Value, Maximum	94.90%	[7]	93.28%	[8]	93.40%	[9]
Fair Value Inputs, Fair Value As Percentage of Par Value, Weighted Average	92.93%	[7]	92.58%	[8]	92.20%	[9]
Investment Grade Tax Exempt Securities Yield Spread Over Comparable Securities Minimum	360		474		467
Investment Grade Tax Exempt Securities Yield Spread Over Comparable Securities Maximum	446		513		525
Available-for-sale securities [Member] | Other debt securities
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Inputs, Asset, Par Value	$ 4,400		$ 4,400		$ 4,400
Fair Value Inputs, Asset, Amortized Cost/Unpaid Principal Balance	4,400		4,400		4,400
Fair Value Inputs, Asset, Fair Value	$ 4,152		$ 4,151		$ 4,152
Fair Value Measurements, Valuation Techniques	Discounted cash flows	[1]	Discounted cash flows	[2]	Discounted cash flows	[3]
Fair Value Measurements, Significant Unobservable Input	Interest rate spread		Interest rate spread		Interest rate spread
Fair Value Inputs, Assets, Discount Rate, Minimum	5.41%	[10]	5.51%	[11]	6.01%	[12]
Fair Value Inputs, Assets, Discount Rate, Maximum	6.72%	[10]	5.96%	[11]	6.26%	[12]
Fair Value Inputs, Assets, Discount Rate, Weighted Average	6.57%	[10]	5.91%	[11]	6.23%	[12]
Fair Value Inputs, Assets, Fair Value As Percentage of Par Value, Minimum	94.31%	[7]	94.32%	[8]	94.34%	[9]
Fair Value Inputs, Assets, Fair Value As Percentage of Par Value, Maximum	94.38%	[7]	94.34%	[8]	94.36%	[9]
Fair Value Inputs, Fair Value As Percentage of Par Value, Weighted Average	94.37%	[7]	94.34%	[8]	94.36%	[9]
Average Yields On Comparable Short-term Taxable Securities, Maximum	3.00%		1.00%		1.00%
Residential mortgage loans held for sale [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Inputs, Asset, Amortized Cost/Unpaid Principal Balance	$ 13,274		$ 10,518		$ 12,431
Fair Value Inputs, Asset, Fair Value	$ 12,563		$ 9,749		$ 11,617
Fair Value Measurements, 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		Quoted prices of loans sold in securitization transactions, with a liquidity discount applied
Fair Value Measurements, Significant Unobservable Input	Liquidity discount applied to the market value of a mortgage loans qualifying for sale to U.S. government agencies.		Liquidity discount applied to the market value of a mortgage loans qualifying for sale to U.S. government agencies.		Liquidity discount applied to the market value of a mortgage loans qualifying for sale to U.S. government agencies.
Liquidity Discount on Mortgage Loans Qualifying for Sale to US Govt Agencies	94.64%		92.69%		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]	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]	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
[4]	Interest rate yields used to value investment grade tax-exempt securities represent a spread of 360 to 446 basis points over average yields for comparable tax-exempt securities.
[5]	Interest rate yields used to value investment grade tax-exempt securities represent a spread of 474 to 513 basis points over average yields for comparable tax-exempt securities.
[6]	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.
[7]	Represents fair value as a percentage of par value.
[8]	Represents fair value as a percentage of par value.
[9]	Represents fair value as a percentage of par value.
[10]	Interest rate yields used to value investment grade taxable securities based on comparable short-term taxable securities which are generally yielding less than 3 percent.
[11]	Interest rate yields used to value investment grade taxable securities based on comparable short-term taxable securities which are generally yielding less than 1 percent.
[12]	Interest rate yields used to value investment grade taxable securities based on comparable short-term taxable securities which are generally yielding less than 1 percent.

Fair Value Measurements, Fair62

Fair Value Measurements, Fair Value Measured On a Nonrecurring Basis (Details) - Fair Value, Measurements, Nonrecurring [Member] - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Impaired Loans [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Gross charge-offs against allowance for loan losses	$ 232	$ 7,041	$ 676	$ 29,186
Net losses and expenses of repossessed assets, net	0	0	0	0
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	0	0
Net losses and expenses of repossessed assets, net	772	751	906	1,068
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	0	0
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	0	0
Fair Value, Inputs, Level 2 [Member] | Impaired Loans [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying Value	464	634	464	634
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	3,488	5,709	3,488	5,709
Fair Value, Inputs, Level 3 [Member] | Impaired Loans [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying Value	3,570	42,342	3,570	42,342
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	$ 530	$ 1,693	$ 530	$ 1,693

Fair Value Measurements Fair 63

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		3 Months Ended
		Jun. 30, 2017		Jun. 30, 2016
Impaired Loans [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Carrying Value		$ 3,570		$ 42,342
Fair Value Measurements, Valuation Techniques		Discounted cash flows		Discounted cash flows
Fair Value Measurements, Significant Unobservable Input		Recoverable oil and gas reserves, forward-looking commodity prices, estimated operating costs		Recoverable oil and gas reserves, forward-looking commodity prices, estimated operating costs
Fair Value of Impaired Loans as a Percentage of Unpaid Principal Balance [Abstract]
Fair Value Measurements, Fair Value of Impaired Loans as a Percentage of Unpaid Principal Balance, Minimum	[1]	75.00%		25.00%
Fair Value Measurements, Fair Value of Impaired Loans as a Percentage of Unpaid Principal Balance, Maximum	[1]	90.00%		71.00%
Fair Value of Impaired Loans as a Percentage of Unpaid Principal Balance, Weighted Average	[1]	83.00%		58.00%
Real estate and other repossessed assets [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Carrying Value		$ 530		$ 1,693
Fair Value Measurements, Valuation Techniques		Appraised value, as adjusted		Appraised value, as adjusted
Fair Value Measurements, Significant Unobservable Input		Marketability adjustment off appraised value2	[2]	Marketability adjustments off appraised value2	[3]
Fair Value of Real Estate and Other Repossessed Assets as a Percentage of Appraised Value [Abstract]
Fair Value Measurement, Percentage of Appraised Value. Minimum		65.00%		68.00%
Fair Value Measurement, Percentage of Appraised Value, Maximum		88.00%		80.00%
Fair Value Measurement, Percentage of Appraised Value, Weighted Average		80.00%		71.00%
[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]	2 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	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Interest-bearing cash and cash equivalents	$ 2,078,831		$ 1,916,651	$ 1,907,838
Trading securities	441,414		337,628	211,622
Investment securities	490,426		546,145	560,711
Available for sale securities	8,341,041		8,676,829	8,830,689
Fair value option securities	445,169		77,046	263,265
Residential mortgage loans held for sale	287,259		301,897	430,728
Loans	17,183,645		16,989,660	16,406,749
Allowance for loan losses	(250,061)	$ (248,710)	(246,159)	(243,259)	$ (233,156)	$ (225,524)
Loans, net of allowance	16,933,584		16,743,501	16,163,490
Mortgage servicing rights	245,239	249,403	247,073	190,747	196,055	218,605
Derviative contracts, net of cash collateral, Assets, Fair value	280,289		689,872	883,673
Time deposits	2,196,122		2,221,800	2,247,061
Subordinated debentures	144,658		144,640	371,812
Derivative contracts, net of cash collateral, Liabilities, Fair Value	285,819		664,531	719,159
Fair Value Assumptions and Methodology for Assets and Liabilities [Abstract]
Specific allocation of allowance for loan losses included in fair value of loans	223,000		218,000	217,000
Commercial
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	10,637,955		10,390,824	10,356,437
Allowance for loan losses	(137,742)	(137,616)	(140,213)	(145,139)	(139,793)	(130,334)
Commercial real estate
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	3,688,592		3,809,046	3,581,966
Allowance for loan losses	(58,580)	(58,343)	(50,749)	(46,745)	(44,453)	(41,391)
Residential mortgage
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	1,939,198		1,949,832	1,880,923
Allowance for loan losses	(18,259)	(18,177)	(18,224)	(18,690)	(18,467)	(19,509)
Personal
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	917,900		839,958	587,423
Allowance for loan losses	(8,106)	$ (7,247)	(8,773)	(6,001)	$ (5,022)	$ (4,164)
U.S. government agency debentures
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	20,954		6,234	18,909
U.S. government agency residential mortgage-backed securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	365,171		310,067	122,306
Available for sale securities	5,382,377		5,460,386	5,700,268
Fair value option securities	445,169		77,046	237,959
Municipal and other tax-exempt securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	45,444		14,427	52,721
Investment securities	267,375		320,364	334,551
Available for sale securities	32,765		40,993	50,262
Other trading securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	9,845		6,900	17,686
U.S. Treasury
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale securities	998		999	1,004
Fair value option securities	0		0	25,306
Privately issued residential mortgage-backed securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale securities	103,383		115,535	126,313
Commercial mortgage-backed securities guaranteed by U.S. government agencies
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale securities	2,782,070		3,017,933	2,911,946
Other debt securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities	205,016		205,004	202,410
Available for sale securities	4,152		4,152	4,151
Perpetual preferred stock
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale securities	16,568		18,474	17,931
Equity securities and mutual funds
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale securities	18,728		18,357	18,814
Carrying (Reported) Amount, Fair Value Disclosure [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and due from banks	561,587		620,846	498,713
Interest-bearing cash and cash equivalents	2,078,831		1,916,651	1,907,838
Trading securities	441,414		337,628	211,622
Investment securities	490,426		546,145	560,711
Available for sale securities	8,341,041		8,676,829	8,830,689
Fair value option securities				263,265
Residential mortgage loans held for sale	287,259		301,897	430,728
Loans	17,183,645		16,989,660	16,406,749
Allowance for loan losses	(250,061)		(246,159)	(243,259)
Loans, net of allowance	16,933,584		16,743,501	16,163,490
Mortgage servicing rights	245,239		247,073	190,747
Derviative contracts, net of cash collateral, Assets, Fair value	280,289		689,872	883,673
Deposits with no stated maturity	20,120,352		20,526,295	18,512,740
Time deposits	2,196,122		2,221,800	2,247,061
Other borrowed funds	5,696,666		5,572,662	6,360,199
Subordinated debentures	144,658		144,640	371,812
Derivative contracts, net of cash collateral, Liabilities, Fair Value	285,819		664,531	719,159
Carrying (Reported) Amount, Fair Value Disclosure [Member] | Commercial
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	10,637,955		10,390,824	10,356,437
Carrying (Reported) Amount, Fair Value Disclosure [Member] | Commercial real estate
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	3,688,592		3,809,046	3,581,966
Carrying (Reported) Amount, Fair Value Disclosure [Member] | Residential mortgage
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	1,939,198		1,949,832	1,880,923
Carrying (Reported) Amount, Fair Value Disclosure [Member] | Personal
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	917,900		839,958	587,423
Carrying (Reported) Amount, Fair Value Disclosure [Member] | U.S. government agency debentures
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	20,954		6,234	18,909
Carrying (Reported) Amount, Fair Value Disclosure [Member] | U.S. government agency residential mortgage-backed securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	365,171		310,067	122,306
Investment securities	18,035		20,777	23,750
Available for sale securities	5,382,377		5,460,386	5,700,268
Fair value option securities	445,169		77,046	237,959
Carrying (Reported) Amount, Fair Value Disclosure [Member] | Municipal and other tax-exempt securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	45,444		14,427	52,721
Investment securities	267,375		320,364	334,551
Available for sale securities	32,765		40,993	50,262
Carrying (Reported) Amount, Fair Value Disclosure [Member] | Other trading securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	9,845		6,900	17,686
Carrying (Reported) Amount, Fair Value Disclosure [Member] | U.S. Treasury
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale securities	998		999	1,004
Fair value option securities				25,306
Carrying (Reported) Amount, Fair Value Disclosure [Member] | Privately issued residential mortgage-backed securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale securities	103,383		115,535	126,313
Carrying (Reported) Amount, Fair Value Disclosure [Member] | Commercial mortgage-backed securities guaranteed by U.S. government agencies
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale securities	2,782,070		3,017,933	2,911,946
Carrying (Reported) Amount, Fair Value Disclosure [Member] | Other debt securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities	205,016		205,004	202,410
Available for sale securities	4,152		4,152	4,151
Carrying (Reported) Amount, Fair Value Disclosure [Member] | Perpetual preferred stock
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale securities	16,568		18,474	17,931
Carrying (Reported) Amount, Fair Value Disclosure [Member] | Equity securities and mutual funds
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale securities	18,728		18,357	18,814
Estimate of Fair Value, Fair Value Disclosure [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and due from banks	561,587		620,846	498,713
Interest-bearing cash and cash equivalents	2,078,831		1,916,651	1,907,838
Trading securities	441,414		337,628	211,622
Investment securities	515,675		565,493	599,062
Available for sale securities	8,341,041		8,676,829	8,830,689
Fair value option securities				263,265
Residential mortgage loans held for sale	287,259		301,897	430,728
Loans	16,909,701		17,178,060	16,231,640
Allowance for loan losses	0		0	0
Loans, net of allowance	16,909,701		17,178,060	16,231,640
Mortgage servicing rights	245,239		247,073	190,747
Derviative contracts, net of cash collateral, Assets, Fair value	280,289		689,872	883,673
Deposits with no stated maturity	20,120,352		20,526,295	18,512,740
Time deposits	2,164,115		2,218,303	2,252,212
Other borrowed funds	5,664,273		5,556,327	6,342,885
Subordinated debentures	147,204		128,903	371,808
Derivative contracts, net of cash collateral, Liabilities, Fair Value	285,819		664,531	719,159
Estimate of Fair Value, Fair Value Disclosure [Member] | Commercial
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	10,413,704		10,437,016	10,172,701
Estimate of Fair Value, Fair Value Disclosure [Member] | Commercial real estate
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	3,636,365		3,850,981	3,563,378
Estimate of Fair Value, Fair Value Disclosure [Member] | Residential mortgage
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	1,950,577		2,025,159	1,913,208
Estimate of Fair Value, Fair Value Disclosure [Member] | Personal
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	909,055		864,904	582,353
Estimate of Fair Value, Fair Value Disclosure [Member] | U.S. government agency debentures
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	20,954		6,234	18,909
Estimate of Fair Value, Fair Value Disclosure [Member] | U.S. government agency residential mortgage-backed securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	365,171		310,067	122,306
Investment securities	18,642		21,473	25,233
Available for sale securities	5,382,377		5,460,386	5,700,268
Fair value option securities	445,169		77,046	237,959
Estimate of Fair Value, Fair Value Disclosure [Member] | Municipal and other tax-exempt securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	45,444		14,427	52,721
Investment securities	270,531		321,225	340,700
Available for sale securities	32,765		40,993	50,262
Estimate of Fair Value, Fair Value Disclosure [Member] | Other trading securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	9,845		6,900	17,686
Estimate of Fair Value, Fair Value Disclosure [Member] | U.S. Treasury
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale securities	998		999	1,004
Fair value option securities				25,306
Estimate of Fair Value, Fair Value Disclosure [Member] | Privately issued residential mortgage-backed securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale securities	103,383		115,535	126,313
Estimate of Fair Value, Fair Value Disclosure [Member] | Commercial mortgage-backed securities guaranteed by U.S. government agencies
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale securities	2,782,070		3,017,933	2,911,946
Estimate of Fair Value, Fair Value Disclosure [Member] | Other debt securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities	226,502		222,795	233,129
Available for sale securities	4,152		4,152	4,151
Estimate of Fair Value, Fair Value Disclosure [Member] | Perpetual preferred stock
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale securities	16,568		18,474	17,931
Estimate of Fair Value, Fair Value Disclosure [Member] | Equity securities and mutual funds
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale securities	18,728		18,357	18,814
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	561,587		620,846	498,713
Interest-bearing cash and cash equivalents	2,078,831		1,916,651	1,907,838
Trading securities	0		0	0
Investment securities	0		0	0
Available for sale securities	4,514		4,494	4,789
Fair value option securities				25,306
Residential mortgage loans held for sale	0		0	0
Loans	0		0	0
Allowance for loan losses	0		0	0
Loans, net of allowance	0		0	0
Mortgage servicing rights	0		0	0
Derviative contracts, net of cash collateral, Assets, Fair value	46,366		7,541	7,246
Deposits with no stated maturity	0		0	0
Time deposits	0		0	0
Other borrowed funds	0		0	0
Subordinated debentures	0		0	0
Derivative contracts, net of cash collateral, Liabilities, Fair Value	20,915		6,972	4,808
Fair Value, Inputs, Level 1 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Commercial
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	0		0	0
Fair Value, Inputs, Level 1 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Commercial real estate
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	0		0	0
Fair Value, Inputs, Level 1 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Residential mortgage
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	0		0	0
Fair Value, Inputs, Level 1 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Personal
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	0		0	0
Fair Value, Inputs, Level 1 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | U.S. government agency debentures
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	0		0	0
Fair Value, Inputs, Level 1 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | U.S. government agency residential mortgage-backed securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	0		0	0
Investment securities	0		0	0
Available for sale securities	0		0	0
Fair value option securities	0		0	0
Fair Value, Inputs, Level 1 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Municipal and other tax-exempt securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	0		0	0
Investment securities	0		0	0
Available for sale securities	0		0	0
Fair Value, Inputs, Level 1 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Other trading securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	0		0	0
Fair Value, Inputs, Level 1 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | U.S. Treasury
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale securities	998		999	1,004
Fair value option securities				25,306
Fair Value, Inputs, Level 1 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Privately issued residential mortgage-backed securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale securities	0		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
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale securities	0		0	0
Fair Value, Inputs, Level 1 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Other debt securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities	0		0	0
Available for sale securities	0		0	0
Fair Value, Inputs, Level 1 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Perpetual preferred stock
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale securities	0		0	0
Fair Value, Inputs, Level 1 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Equity securities and mutual funds
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale securities	3,516		3,495	3,785
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	0
Interest-bearing cash and cash equivalents	0		0	0
Trading securities	441,414		337,628	211,622
Investment securities	515,675		565,493	599,062
Available for sale securities	8,327,720		8,662,394	8,812,149
Fair value option securities				237,959
Residential mortgage loans held for sale	274,524		290,280	420,979
Loans	0		0	0
Allowance for loan losses	0		0	0
Loans, net of allowance	0		0	0
Mortgage servicing rights	0		0	0
Derviative contracts, net of cash collateral, Assets, Fair value	233,923		682,331	876,427
Deposits with no stated maturity	0		0	0
Time deposits	0		0	0
Other borrowed funds	0		0	0
Subordinated debentures	147,204		128,903	150,234
Derivative contracts, net of cash collateral, Liabilities, Fair Value	264,904		657,559	714,351
Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Commercial
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	0		0	0
Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Commercial real estate
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	0		0	0
Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Residential mortgage
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	0		0	0
Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Personal
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	0		0	0
Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | U.S. government agency debentures
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	20,954		6,234	18,909
Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | U.S. government agency residential mortgage-backed securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	365,171		310,067	122,306
Investment securities	18,642		21,473	25,233
Available for sale securities	5,382,377		5,460,386	5,700,268
Fair value option securities	445,169		77,046	237,959
Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Municipal and other tax-exempt securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	45,444		14,427	52,721
Investment securities	270,531		321,225	340,700
Available for sale securities	28,110		35,204	40,662
Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Other trading securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	9,845		6,900	17,686
Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | U.S. Treasury
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale securities	0		0	0
Fair value option securities				0
Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Privately issued residential mortgage-backed securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale securities	103,383		115,535	126,313
Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Commercial mortgage-backed securities guaranteed by U.S. government agencies
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale securities	2,782,070		3,017,933	2,911,946
Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Other debt securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities	226,502		222,795	233,129
Available for sale securities	0		0	0
Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Perpetual preferred stock
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale securities	16,568		18,474	17,931
Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Equity securities and mutual funds
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale securities	15,212		14,862	15,029
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	0
Interest-bearing cash and cash equivalents	0		0	0
Trading securities	0		0	0
Investment securities	0		0	0
Available for sale securities	8,807		9,941	13,751
Fair value option securities				0
Residential mortgage loans held for sale	12,735		11,617	9,749
Loans	16,909,701		17,178,060	16,231,640
Allowance for loan losses	0		0	0
Loans, net of allowance	16,909,701		17,178,060	16,231,640
Mortgage servicing rights	245,239		247,073	190,747
Derviative contracts, net of cash collateral, Assets, Fair value	0		0	0
Deposits with no stated maturity	20,120,352		20,526,295	18,512,740
Time deposits	2,164,115		2,218,303	2,252,212
Other borrowed funds	5,664,273		5,556,327	6,342,885
Subordinated debentures	0		0	221,574
Derivative contracts, net of cash collateral, Liabilities, Fair Value	0		0	0
Fair Value, Inputs, Level 3 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Commercial
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	10,413,704		10,437,016	10,172,701
Fair Value, Inputs, Level 3 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Commercial real estate
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	3,636,365		3,850,981	3,563,378
Fair Value, Inputs, Level 3 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Residential mortgage
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	1,950,577		2,025,159	1,913,208
Fair Value, Inputs, Level 3 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Personal
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	909,055		864,904	582,353
Fair Value, Inputs, Level 3 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | U.S. government agency debentures
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	0		0	0
Fair Value, Inputs, Level 3 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | U.S. government agency residential mortgage-backed securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	0		0	0
Investment securities	0		0	0
Available for sale securities	0		0	0
Fair value option securities	0		0	0
Fair Value, Inputs, Level 3 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Municipal and other tax-exempt securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	0		0	0
Investment securities	0		0	0
Available for sale securities	4,655		5,789	9,600
Fair Value, Inputs, Level 3 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Other trading securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	0		0	0
Fair Value, Inputs, Level 3 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | U.S. Treasury
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale securities	0		0	0
Fair value option securities				0
Fair Value, Inputs, Level 3 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Privately issued residential mortgage-backed securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale securities	0		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
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale securities	0		0	0
Fair Value, Inputs, Level 3 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Other debt securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities	0		0	0
Available for sale securities	4,152		4,152	4,151
Fair Value, Inputs, Level 3 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Perpetual preferred stock
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale securities	0		0	0
Fair Value, Inputs, Level 3 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Equity securities and mutual funds
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale securities	$ 0		$ 0	$ 0

Fair Value Measurements Financi

Fair Value Measurements Financial Instruments, Quantitative Information (Details)	6 Months Ended		12 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Time deposits [Member]
Fair Value Inputs, Financial Instruments, Quantitative Information [Line Items]
Contractual Yield, Minimum	0.03%	0.03%	0.02%
Contractual Yield, Maximum	10.00%	9.64%	9.65%
Repricing (in years)	1 year 332 days	2 years 55 days	1 year 350 days
Discount Rate, Minimum	1.81%	1.16%	1.57%
Discount Rate, Maximum	2.12%	1.43%	2.00%
Other borrowings [Member]
Fair Value Inputs, Financial Instruments, Quantitative Information [Line Items]
Contractual Yield, Minimum	0.25%	0.25%	0.25%
Contractual Yield, Maximum	3.58%	3.28%	3.50%
Repricing (in years)	7 days	7 days	1 day
Discount Rate, Minimum	1.06%	0.30%	0.55%
Discount Rate, Maximum	3.69%	2.92%	3.22%
Subordinated debentures [Member]
Fair Value Inputs, Financial Instruments, Quantitative Information [Line Items]
Contractual Yield, Minimum	5.38%	1.32%	5.38%
Contractual Yield, Maximum	5.38%	5.38%	5.38%
Repricing (in years)	16 years 329 days	8 years 128 days	16 years 314 days
Discount Rate, Minimum	4.89%	2.16%	6.11%
Discount Rate, Maximum	4.89%	5.38%	6.11%
Commercial | Loans Receivable [Member]
Fair Value Inputs, Financial Instruments, Quantitative Information [Line Items]
Contractual Yield, Minimum	0.38%	0.38%	0.38%
Contractual Yield, Maximum	30.00%	30.00%	30.00%
Repricing (in years)	234 days	252 days	256 days
Discount Rate, Minimum	0.71%	0.55%	0.64%
Discount Rate, Maximum	4.56%	3.68%	4.60%
Commercial real estate | Loans Receivable [Member]
Fair Value Inputs, Financial Instruments, Quantitative Information [Line Items]
Contractual Yield, Minimum	0.38%	0.38%	0.38%
Contractual Yield, Maximum	18.00%	18.00%	18.00%
Repricing (in years)	281 days	266 days	259 days
Discount Rate, Minimum	1.03%	0.80%	0.94%
Discount Rate, Maximum	4.31%	3.65%	4.27%
Residential mortgage | Loans Receivable [Member]
Fair Value Inputs, Financial Instruments, Quantitative Information [Line Items]
Contractual Yield, Minimum	1.74%	1.70%	1.74%
Contractual Yield, Maximum	18.00%	18.00%	18.00%
Repricing (in years)	2 years 66 days	1 year 354 days	2 years 99 days
Discount Rate, Minimum	1.75%	1.25%	1.71%
Discount Rate, Maximum	4.19%	3.75%	4.26%
Personal | Loans Receivable [Member]
Fair Value Inputs, Financial Instruments, Quantitative Information [Line Items]
Contractual Yield, Minimum	0.25%	0.25%	0.25%
Contractual Yield, Maximum	21.00%	21.00%	21.00%
Repricing (in years)	102 days	128 days	146 days
Discount Rate, Minimum	0.70%	0.71%	1.03%
Discount Rate, Maximum	4.68%	3.91%	4.59%

Federal and State Income Taxe66

Federal and State Income Taxes Federal and State Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Effective Income Tax Rate Reconciliation, Amount [Abstract]
Federal statutory tax	$ 47,800	$ 33,869	$ 92,168	$ 55,715
Tax exempt revenue	(3,224)	(2,568)	(6,335)	(5,100)
Effect of state income taxes, net of federal benefit	2,944	1,557	5,389	3,858
Utilization of tax credits:
Low-income housing tax credit, net of amortization	(526)	(572)	(2,249)	(1,882)
Other tax credits	(363)	(521)	(727)	(1,042)
Bank-owned life insurance	(775)	(810)	(1,547)	(1,601)
Share-based compensation	1,636	0	(2,301)	0
Other, net	213	(458)	1,410	1,977
Total income tax expense	$ 47,705	$ 30,497	$ 85,808	$ 51,925
Effective Income Tax Rate Reconciliation, Percent [Abstract]
Federal statutory tax (in hundredths)	35.00%	35.00%	35.00%	35.00%
Tax exempt revenue (in hundredths)	(2.40%)	(2.70%)	(2.40%)	(3.20%)
Effect of state income taxes, net of federal benefit (in hundredths)	2.20%	1.60%	2.00%	2.40%
Utilization of tax credits: [Abstract]
Low-income housing tax credit, net of amortization (in hundredths)	(0.40%)	(0.60%)	(0.80%)	(1.20%)
Other tax credits (in hundredths)	(0.30%)	(0.50%)	(0.30%)	(0.60%)
Effective Income Tax Rate Reconciliation, Deduction, Other, Percent	0.60%	0.80%	0.60%	1.00%
Share-based compensation (in hundredths)	1.20%	0.00%	(0.90%)	0.00%
Other, net (in hundredths)	0.20%	(0.50%)	0.60%	1.20%
Total (in hundredths)	34.90%	31.50%	32.60%	32.60%