Associated Banc-Corp (ASB) 10-Q 26 Oct 17 2017 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2017	Oct. 25, 2017
Document And Entity Information [Abstract]
Trading Symbol	ASB
Entity Registrant Name	ASSOCIATED BANC-CORP
Entity Central Index Key	7,789
Document Type	10-Q
Document Period End Date	Sep. 30, 2017
Amendment Flag	false
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	Q3
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 Common Stock, Shares Outstanding		151,164,803

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands		Sep. 30, 2017	Dec. 31, 2016
Assets
Cash and due from banks		$ 354,331	$ 446,558
Interest-bearing deposits in other financial institutions		109,596	149,175
Federal funds sold and securities purchased under agreements to resell		27,700	46,500
Investment securities held to maturity, at amortized cost		2,233,579	1,273,536
Investment securities available for sale, at fair value		3,801,699	4,680,226
Federal Home Loan Bank and Federal Reserve Bank stocks, at cost		172,446	140,001
Residential loans held for sale	[1]	113,064	108,010
Commercial loans held for sale		9,718	12,474
Loans		20,931,460	20,054,716
Allowance for loan losses		(276,551)	(278,335)
Loans, net		20,654,909	19,776,381
Premises and equipment, net		330,065	330,315
Bank and corporate owned life insurance		589,093	585,290
Goodwill		972,006	971,951
Mortgage servicing rights, net		58,377	61,476
Other intangible assets, net		14,080	15,377
Trading assets		48,429	52,398
Other assets		575,455	489,647
Total assets		30,064,547	29,139,315
Liabilities and Stockholders’ Equity
Noninterest-bearing demand deposits		5,177,734	5,392,208
Interest-bearing deposits		17,155,717	16,496,240
Total deposits		22,333,451	21,888,448
Federal funds purchased and securities sold under agreements to repurchase		476,550	508,347
Other short-term funding		588,067	583,688
Long-term funding		3,147,285	2,761,795
Trading liabilities		46,812	51,103
Accrued expenses and other liabilities		268,781	254,622
Total liabilities		26,860,946	26,048,003
Stockholders’ Equity
Preferred equity		159,929	159,929
Common stock		1,615	1,630
Surplus		1,442,328	1,459,498
Retained earnings		1,792,184	1,695,764
Accumulated other comprehensive income (loss)		(54,288)	(54,679)
Treasury stock, at cost		(138,167)	(170,830)
Total common equity		3,043,672	2,931,383
Total stockholders’ equity		3,203,601	3,091,312
Total liabilities and stockholders’ equity		$ 30,064,547	$ 29,139,315
Preferred shares issued (in shares)		165,000	165,000
Preferred shares authorized (par value $1.00 per share) (in shares)		750,000	750,000
Common shares issued (in shares)		161,460,708	163,030,209
Common shares authorized (par value $0.01 per share) (in shares)		250,000,000	250,000,000
Treasury shares of common stock (in shares)		9,143,102	10,909,362
[1]	(1)Effective January 1, 2017, residential loans originated for sale are accounted for under the fair value option. Prior periods have not been restated. For more information on this accounting policy change, please refer to Note 3 to Notes to the Consolidated Financial Statements.

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Sep. 30, 2017	Dec. 31, 2016
Statement of Financial Position [Abstract]
Preferred shares, par value	$ 1	$ 1
Common shares, par value	$ 0.01	$ 0.01

Consolidated Statements of Inco

Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Interest Income
Interest and fees on loans	$ 196,972	$ 167,350	$ 554,867	$ 490,065
Interest and dividends on investment securities:
Taxable	24,162	22,948	71,295	72,734
Tax exempt	8,268	8,141	24,540	23,865
Other interest	2,492	1,064	5,581	3,449
Total interest income	231,894	199,503	656,283	590,113
Interest Expense
Interest on deposits	27,778	13,118	65,882	36,562
Interest on Federal funds purchased and securities sold under agreements to repurchase	768	326	2,107	1,000
Interest on other short-term funding	1,039	296	3,946	1,656
Interest on long-term funding	12,187	7,229	30,133	23,657
Total interest expense	41,772	20,969	102,068	62,875
NET INTEREST INCOME	190,122	178,534	554,215	527,238
Provision for credit losses	5,000	21,000	26,000	55,000
Net interest income after provision for credit losses	185,122	157,534	528,215	472,238
Noninterest Income
Trust service fees	12,785	11,700	37,066	34,656
Service charges on deposit accounts	16,268	17,445	48,654	50,162
Card-based and other nondeposit fees	12,619	12,777	38,848	37,485
Insurance commissions	19,815	19,431	62,288	62,818
Brokerage and annuity commissions	4,392	4,155	13,071	12,047
Mortgage banking, net	6,585	18,291	16,191	26,562
Capital market fees, net	4,610	7,012	12,535	14,343
Bank and Corporate Owned Life Insurance Income	6,580	3,290	13,094	11,033
Asset gains (losses), net	(16)	(1,034)	(716)	(853)
Investment securities gains (losses), net	3	(13)	359	6,201
Other	2,254	2,180	6,746	6,140
Total noninterest income	85,895	95,234	248,136	260,594
Noninterest Expense
Personnel expense	105,852	103,819	314,954	307,346
Occupancy	12,294	15,362	40,345	42,379
Equipment	5,232	5,319	15,951	16,161
Technology	15,233	14,173	45,126	42,887
Business development and advertising	7,764	5,251	20,751	20,053
Other intangible amortization	450	525	1,459	1,568
Loan expense	3,330	3,535	8,924	10,198
Legal and professional fees	6,248	4,804	16,125	14,685
Foreclosure / OREO expense, net	906	960	3,593	4,167
FDIC expense	7,800	9,000	23,800	25,500
Other	12,318	12,566	36,406	38,701
Total noninterest expense	177,427	175,314	527,434	523,645
Income before income taxes	93,590	77,454	248,917	209,187
Income tax expense	28,589	23,638	69,663	63,746
Net income	65,001	53,816	179,254	145,441
Preferred stock dividends	2,339	2,188	7,008	6,555
Net income available to common equity	$ 62,662	$ 51,628	$ 172,246	$ 138,886
Earnings per common share:
Basic (in usd per share)	$ 0.41	$ 0.34	$ 1.13	$ 0.92
Diluted (in usd per share)	$ 0.41	$ 0.34	$ 1.11	$ 0.92
Average common shares outstanding:
Basic (in shares)	150,565	148,708	150,983	148,607
Diluted (in shares)	152,968	149,973	153,782	149,645

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Statement of Comprehensive Income [Abstract]
Net income	$ 65,001	$ 53,816	$ 179,254	$ 145,441
Investment securities available for sale
Net unrealized gains (losses)	(1,986)	(22,894)	16,384	59,849
Net unrealized gain (loss) on available for sale securities transferred to held to maturity securities	0	0	(14,738)	0
Amortization of net unrealized gain (loss) on available for sale securities transferred to held to maturity securities	76	(1,441)	(2,499)	(4,465)
Reclassification adjustment for net gains (losses) realized in net income(1)	0	13	0	(6,201)
Income tax (expense) benefit	734	9,280	328	(18,768)
Other comprehensive income (loss) on investment securities available for sale	(1,176)	(15,042)	(525)	30,415
Defined benefit pension and postretirement obligations
Amortization of prior service cost	(38)	(80)	(113)	(55)
Amortization of actuarial loss (gains)	621	621	1,596	1,586
Income tax (expense) benefit	(225)	(206)	(567)	(584)
Other comprehensive income (loss) on pension and postretirement obligations	358	335	916	947
Total other comprehensive income (loss)	(818)	(14,707)	391	31,362
Comprehensive income	$ 64,183	$ 39,109	$ 179,645	$ 176,803

Consolidated Statements of Chan

Consolidated Statements of Changes in Stockholders' Equity (Unaudited) - USD ($) $ in Thousands	Total	Preferred Equity	Common Stock	Surplus	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Treasury Stock
Beginning balance at Dec. 31, 2015	$ 2,937,246	$ 121,379	$ 1,642	$ 1,458,522	$ 1,593,239	$ (32,616)	$ (204,920)
Comprehensive income:
Net income	145,441	0	0	0	145,441	0	0
Other comprehensive income	31,362	0	0	0	0	31,362	0
Comprehensive income	176,803
Common stock issued:
Stock-based compensation plans, net	7,749	0	0	1,785	(18,070)	0	24,034
Purchase of common stock returned to authorized but unissued	(20,007)	0	(12)	(19,995)	0	0	0
Purchase of treasury stock	(4,243)	0	0	0	0	0	(4,243)
Cash dividends:
Common stock dividends ($0.33 per share in 2016 and $0.36 per share in 2017)	(49,642)	0	0	0	(49,642)	0	0
Preferred stock dividends	(6,555)	0	0	0	(6,555)	0	0
Issuance of preferred stock	97,066	97,066	0	0	0	0	0
Redemption of preferred stock	(58,903)	(57,338)	0	0	(1,565)	0	0
Purchase of preferred stock	(1,248)	(1,178)	0	0	(70)	0	0
Stock-based compensation expense, net	18,047	0	0	18,047	0	0	0
Other	802	0	0	802	0	0	0
Ending balance at Sep. 30, 2016	3,097,115	159,929	1,630	1,459,161	1,662,778	(1,254)	(185,129)
Beginning balance at Dec. 31, 2016	3,091,312	159,929	1,630	1,459,498	1,695,764	(54,679)	(170,830)
Comprehensive income:
Net income	179,254	0	0	0	179,254	0	0
Other comprehensive income	391	0	0	0	0	391	0
Comprehensive income	179,645
Common stock issued:
Stock-based compensation plans, net	22,460	0	0	1,952	(20,768)	0	41,276
Purchase of common stock returned to authorized but unissued	(37,031)		(15)	(37,016)	0	0	0
Purchase of treasury stock	(8,613)	0	0	0	0	0	(8,613)
Cash dividends:
Common stock dividends ($0.33 per share in 2016 and $0.36 per share in 2017)	(55,058)	0	0	0	(55,058)	0	0
Preferred stock dividends	(7,008)	0	0	0	(7,008)	0	0
Stock-based compensation expense, net	16,860	0	0	16,860	0	0	0
Other	1,034	0	0	1,034	0	0	0
Ending balance at Sep. 30, 2017	$ 3,203,601	$ 159,929	$ 1,615	$ 1,442,328	$ 1,792,184	$ (54,288)	$ (138,167)

Consolidated Statements of Cha7

Consolidated Statements of Changes in Stockholders' Equity (Parenthetical) - $ / shares	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Common Stock
Cash dividends:
Common stock dividends (usd per share)	$ 0.36	$ 0.33

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
CASH FLOWS FROM OPERATING ACTIVITIES
Net income	$ 65,001	$ 53,816	$ 179,254	$ 145,441
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for credit losses	5,000	21,000	26,000	55,000
Depreciation and amortization			35,054	34,121
Addition to valuation allowance on mortgage servicing rights, net			286	2,486
Amortization of mortgage servicing rights			7,635	9,142
Amortization of other intangible assets	450	525	1,459	1,568
Amortization and accretion on earning assets, funding, and other, net			27,230	34,077
Other Depreciation and Amortization			14,685	4,437
Gain on sales of investment securities, net			(359)	(6,201)
Asset (gains) losses, net	16	1,034	716	853
(Gain) loss on mortgage banking activities, net			(3,762)	(21,741)
Mortgage loans originated and acquired for sale			(466,135)	(983,930)
Proceeds from sales of mortgage loans held for sale			551,697	1,147,278
Payment for Pension Benefits			(6,242)	0
(Increase) decrease in interest receivable			(9,765)	(5,809)
Increase (decrease) in interest payable			3,410	(5,994)
Other, net			(44,882)	5,451
Net cash provided by operating activities			316,281	416,179
CASH FLOWS FROM INVESTING ACTIVITIES
Net increase in loans			(991,334)	(1,461,884)
Purchases of:
Available for sale securities			(701,080)	(849,466)
Held to maturity securities			(121,596)	(151,556)
Federal Home Loan Bank and Federal Reserve Bank stocks			(195,356)	(72,975)
Premises, equipment, and software, net of disposals			(32,925)	(90,691)
Proceeds from:
Sales of available for sale securities			0	359,591
Sales of held to maturity securities			16,059	0
Proceeds from Sale of Federal Home Loan Bank Stock			162,911	80,000
Prepayments, calls, and maturities of available for sale investment securities			551,962	651,403
Prepayments, calls, and maturities of held to maturity investment securities			151,565	55,579
Sales, prepayments, calls, and maturities of other assets			10,833	19,351
Net Change in Tax Credit Investments [Line Items]			(35,027)	(13,138)
Net cash paid in acquisition			(217)	(685)
Net cash used in investing activities			(1,184,205)	(1,474,471)
CASH FLOWS FROM FINANCING ACTIVITIES
Net increase (decrease) in deposits			445,003	740,047
Proceeds from (Repayments of) Short-term Debt			(27,418)	405,677
Proceeds from (Repayments of) Long-term Debt and Capital Securities			(115,017)	(1,180,027)
Proceeds from issuance of long-term funding			500,000	1,265,000
Proceeds from Issuance of Preferred Stock and Preference Stock			0	97,066
Proceeds from issuance of common stock for stock-based compensation plans			22,460	7,749
Payments for Repurchase of Redeemable Preferred Stock			0	(58,903)
Purchase of preferred stock			0	(1,248)
Purchase of common stock returned to authorized but unissued			(37,031)	(20,007)
Purchase of treasury stock for tax withholding			(8,613)	(4,243)
Cash dividends on common stock			(55,058)	(49,642)
Cash dividends on preferred stock			(7,008)	(6,555)
Net cash provided by financing activities			717,318	1,194,914
Net increase (decrease) in cash and cash equivalents			(150,606)	136,622
Cash and cash equivalents at beginning of period			642,233	473,685	$ 473,685
Cash and cash equivalents at end of period	491,627	610,307	491,627	610,307	$ 642,233
Supplemental disclosures of cash flow information:
Cash paid for interest			98,151	68,371
Cash paid for income taxes			61,959	53,126
Loans and bank premises transferred to other real estate owned			5,872	8,834
Capitalized mortgage servicing rights			4,822	8,701
Loans transferred into held for sale from portfolio, net			75,289	256,188
Fair value of assets acquired, including cash and cash equivalents	0	522	0	522
Fair value ascribed to goodwill and intangible assets	217	4,119	217	4,119
Fair value of liabilities assumed	$ 0	$ 1,423	$ 0	$ 1,423

Basis of Presentation

Basis of Presentation	9 Months Ended
	Sep. 30, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	Basis of Presentation In the opinion of management, the accompanying unaudited consolidated financial statements contain all adjustments necessary to present fairly the financial position, results of operations and comprehensive income, changes in stockholders’ equity, and cash flows of Associated Banc-Corp (individually referred to herein as the “Parent Company,” and together with all of its subsidiaries and affiliates, collectively referred to herein as the “Corporation”) for the periods presented, and all such adjustments are of a normal recurring nature. The consolidated financial statements include the accounts of all subsidiaries. All significant intercompany transactions and balances have been eliminated in consolidation. The results of operations for the interim periods are not necessarily indicative of the results to be expected for the full year.

Acquisitions

Acquisitions	9 Months Ended
	Sep. 30, 2017
Business Combinations [Abstract]
Acquisitions	Acquisitions Completed Acquisitions During the first quarter of 2017, the Corporation completed a small insurance acquisition to complement its existing insurance and benefits related products and services provided by Associated Benefits and Risk Consulting ("ABRC"). The Corporation recorded goodwill of $55,000 and other intangibles of $162,000 related to the insurance acquisition. During the first quarter of 2016, the Corporation completed two small insurance acquisitions to complement its existing insurance and benefits related products and services provided by ABRC. The Corporation recorded goodwill of $3 million and other intangibles of $1 million related to these insurance acquisitions. See Note 8 for additional information on goodwill and other intangible assets. Acquisitions Update On October 2, 2017, the Corporation completed its previously announced acquisition of Whitnell & Co., a wealth management family services firm based in Oak Brook, IL. On July 20, 2017, the Corporation and Bank Mutual Corporation ("Bank Mutual") jointly announced that they had entered into an Agreement and Plan of Merger, dated as of July 20, 2017 (the "Merger Agreement") under which Bank Mutual will merge with and into the Corporation. Under the terms of the Merger Agreement, Bank Mutual's shareholders will receive 0.422

Summary of Significant Accounti

Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2017
New Accounting Pronouncements and Changes in Accounting Principles [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies Accounting Policy Elections Effective January 1, 2017, residential mortgage loans that are classified as held for sale are accounted using the fair value option method of accounting. The Corporation has elected the fair value option to mitigate accounting mismatches between held for sale loan valuations and corresponding derivative commitments. Prior to January 1, 2017, residential mortgage loans that were classified as held for sale were accounted for at the lower of cost or market method (“LOCOM”) of accounting. New Accounting Pronouncements Adopted Standard Description Date of adoption Effect on financial statements ASU 2017-08 Receivables - Nonrefundable Fees and Other Costs (Subtopic 310-20), Premium Amortization on Purchased Callable Debt Securities The FASB issued amendments to require that certain purchased callable debt securities held at a premium be amortized to the earliest call date. The amendments do not require an accounting change for securities held at a discount, which continue to be amortized to maturity. 1st Quarter 2017 The Corporation early adopted the accounting standard with no material impact on results of operations, financial position, or liquidity. ASU 2017-03 Accounting Changes and Error Corrections (Topic 250) and Investments - Equity Method and Joint Ventures (Topic 323) The standard states that for ASUs which have not been adopted yet, the registrant needs to determine the potential effects (if material) of those ASUs on the financial statements when adopted and include the appropriate disclosures in the financial statements. If the impact of adoption is unknown or cannot be estimated, the registrant should include a statement noting this and consider adding qualitative disclosures to the financial statements to assist the reader in evaluating the impact of the ASUs, when adopted, on the financial statements. 1st Quarter 2017 No material impact on results of operations, financial position, or liquidity. ASU 2016-17 Consolidation (Topic 810): Interests Held through Related Parties That Are Under Common Control The FASB issued an amendment to address how a reporting entity that is a single decision maker of a variable interest entity treats indirect interests in the entity held through related parties that are under common control with the reporting entity. 1st Quarter 2017 No material impact on results of operations, financial position, or liquidity. ASU 2016-09 Compensation - Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting The FASB issued an amendment involving several aspects of the accounting for share-based payment transactions, including the income tax consequences, classification of awards as either equity or liabilities, and classification on the statement of cash flows. Entities should apply the amendment related to the timing of when excess tax benefits are recognized, minimum statutory withholding requirements, forfeitures, and intrinsic value using a modified retrospective transition method by means of a cumulative-effect adjustment to equity as of the beginning of the period in which the guidance is adopted. Entities should apply the amendment related to the presentation of employee taxes paid on the statement of cash flows when an employer withholds shares to meet the minimum statutory withholding requirement retrospectively. The amendment requiring recognition of excess tax benefits and tax deficiencies in the income statement and the practical expedient for estimating expected term should be applied prospectively. 4th Quarter 2016 The Corporation early adopted the accounting standard and recognized a $1 million reduction in income taxes for the excess tax benefits on stock-based compensation. The remaining provisions of this accounting standard did not have a material impact on the results of operations, financial position, or liquidity. ASU 2016-07 Investments - Equity Method and Joint Ventures (Topic 323): Simplifying the Transition to the Equity Method of Accounting The FASB issued an amendment to eliminate the requirement that when an investment qualifies for use of the equity method as a result of an increase in the level of ownership interest or degree of influence, an investor must adjust the investment, results of operations, and retained earnings retroactively on a step-by-step basis as if the equity method had been in effect during all previous periods that the investment had been held. The amendment requires that the equity method investor add the cost of acquiring the additional interests in the investee to the current basis of the investor’s previously held interest and adopt the equity method of accounting as of the date the investment becomes qualified for equity method accounting. Therefore, upon qualifying for the equity method of accounting, no retroactive adjustment of the investment is required. The amendment requires that an entity that has an available-for-sale equity security that becomes qualified for the equity method of accounting recognize through earnings the unrealized holding gain or loss in accumulated other comprehensive income at the date the investment becomes qualified for use of the equity method. Entities should apply the amendment prospectively to increases in the level of ownership interest or degree of influence that result in the adoption of the equity method. 1st Quarter 2017 No material impact on results of operations, financial position, or liquidity.

Earnings Per Common Share

Earnings Per Common Share	9 Months Ended
	Sep. 30, 2017
Earnings Per Share [Abstract]
Earnings Per Common Share	Earnings Per Common Share Earnings per common share are calculated utilizing the two-class method. Basic earnings per common share are calculated by dividing the sum of distributed earnings to common shareholders and undistributed earnings allocated to common shareholders by the weighted average number of common shares outstanding. Diluted earnings per common share are calculated by dividing the sum of distributed earnings to common shareholders and undistributed earnings allocated to common shareholders by the weighted average number of common shares outstanding adjusted for the dilutive effect of common stock awards (outstanding stock options and unvested restricted stock awards) and common stock warrants. Presented below are the calculations for basic and diluted earnings per common share. For the Three Months Ended September 30, For the Nine Months Ended September 30, 2017 2016 2017 2016 (In thousands, except per share data) Net income $ 65,001 $ 53,816 $ 179,254 $ 145,441 Preferred stock dividends (2,339 ) (2,188 ) (7,008 ) (6,555 ) Net income available to common equity $ 62,662 $ 51,628 $ 172,246 $ 138,886 Common shareholder dividends (18,149 ) (16,431 ) (54,726 ) (49,077 ) Unvested share-based payment awards (105 ) (177 ) (332 ) (565 ) Undistributed earnings $ 44,408 $ 35,020 $ 117,188 $ 89,244 Undistributed earnings allocated to common shareholders 44,150 34,645 116,418 88,294 Undistributed earnings allocated to unvested share-based payment awards 258 375 770 950 Undistributed earnings $ 44,408 $ 35,020 $ 117,188 $ 89,244 Basic Distributed earnings to common shareholders $ 18,149 $ 16,431 $ 54,726 $ 49,077 Undistributed earnings allocated to common shareholders 44,150 34,645 116,418 88,294 Total common shareholders earnings, basic $ 62,299 $ 51,076 $ 171,144 $ 137,371 Diluted Distributed earnings to common shareholders $ 18,149 $ 16,431 $ 54,726 $ 49,077 Undistributed earnings allocated to common shareholders 44,150 34,645 116,418 88,294 Total common shareholders earnings, diluted $ 62,299 $ 51,076 $ 171,144 $ 137,371 Weighted average common shares outstanding 150,565 148,708 150,983 148,607 Effect of dilutive common stock awards 1,815 1,265 2,081 1,038 Effect of dilutive common stock warrants 588 — 718 — Diluted weighted average common shares outstanding 152,968 149,973 153,782 149,645 Basic earnings per common share $ 0.41 $ 0.34 $ 1.13 $ 0.92 Diluted earnings per common share $ 0.41 $ 0.34 $ 1.11 $ 0.92 Anti-dilutive common stock options of approximately 1 million and 4 million for the three months ended September 30, 2017 and 2016 , respectively, and approximately 1 million and 4 million for the nine months ended September 30, 2017 and 2016, respectively, were excluded from the earnings per common share calculation. Warrants to purchase approximately 4 million shares were outstanding for the three and nine months ended September 30, 2016

Stock-Based Compensation

Stock-Based Compensation	9 Months Ended
	Sep. 30, 2017
Retirement Benefits [Abstract]
Stock-Based Compensation	Stock-Based Compensation The fair value of stock options granted is estimated on the date of grant using a Black-Scholes option pricing model, while the fair value of restricted stock awards is their fair market value on the date of grant. The fair values of stock options and restricted stock awards are amortized as compensation expense on a straight-line basis over the vesting period of the grants. For retirement eligible colleagues, expenses related to stock options and restricted stock awards are fully recognized on the date the colleague meets the definition of normal or early retirement. Compensation expense recognized is included in personnel expense in the consolidated statements of income. Assumptions are used in estimating the fair value of stock options granted. The weighted average expected life of the stock option represents the period of time that stock options are expected to be outstanding and is estimated using historical data of stock option exercises and forfeitures. The risk-free interest rate is based on the U.S. Treasury yield curve in effect at the time of grant. The expected volatility is based on the implied volatility of the Corporation’s stock. The following assumptions were used in estimating the fair value for options granted in the first nine months of 2017 and full year 2016 . 2017 2016 Dividend yield 2.00 % 2.50 % Risk-free interest rate 2.00 % 2.00 % Weighted average expected volatility 25.00 % 25.00 % Weighted average expected life 5.5 years 5.5 years Weighted average per share fair value of options $5.30 $3.36 A summary of the Corporation’s stock option activity for the nine months ended September 30, 2017 is presented below. Stock Options Shares Weighted Average Exercise Price Weighted Average Remaining Contractual Term Aggregate Intrinsic Value (a) Outstanding at December 31, 2016 6,357,843 $ 17.67 6.10 $ 47,902 Granted 799,558 25.61 Exercised (1,291,244 ) 16.32 Forfeited or expired (506,395 ) 31.90 Outstanding at September 30, 2017 5,359,762 $ 18.07 6.55 $ 34,334 Options Exercisable at September 30, 2017 3,072,811 $ 16.54 5.25 $ 23,911 (a) $ in Thousands Intrinsic value represents the amount by which the fair market value of the underlying stock exceeds the exercise price of the stock option. For the nine months ended September 30, 2017 , the intrinsic value of stock options exercised was approximately $12 million . For the nine months ended September 30, 2016 , the intrinsic value of the stock options exercised was $2 million . The total fair value of stock options vested was $4 million and $3 million for the nine months ended September 30, 2017 and September 30, 2016 , respectively. The Corporation recognized compensation expense for the vesting of stock options of $3 million for both the nine months ended September 30, 2017 and September 30, 2016 . Included in compensation expense for 2017 was approximately $570,000 of expense for the accelerated vesting of stock options granted to retirement eligible colleagues. At September 30, 2017 , the Corporation had approximately $5 million of unrecognized compensation expense related to stock options that is expected to be recognized over the remaining requisite service periods that extend predominantly through first quarter 2021 . The following table summarizes information about the Corporation’s restricted stock activity for the nine months ended September 30, 2017 . Restricted Stock Shares Weighted Average Grant Date Fair Value Outstanding at December 31, 2016 2,377,380 $ 17.40 Granted 748,024 25.55 Vested (872,020 ) 17.92 Forfeited (101,703 ) 20.02 Outstanding at September 30, 2017 2,151,681 $ 19.94 The Corporation amortizes the expense related to restricted stock awards as compensation expense over the vesting period specified in the grant's award agreement. Performance-based restricted stock awards granted during 2016 and 2017 will vest ratably over a three year period, while service-based restricted stock awards granted during 2016 and 2017 will vest ratably over a four year period. Expense for restricted stock awards of approximately $14 million was recorded for the nine months ended September 30, 2017 and approximately $15 million for the nine months ended September 30, 2016 . Included in compensation expense for 2017 was approximately $2 million of expense for the accelerated vesting of restricted stock awards granted to retirement eligible colleagues. The Corporation had $22 million of unrecognized compensation costs related to restricted stock awards at September 30, 2017 , that is expected to be recognized over the remaining requisite service periods that extend predominantly through first quarter 2021 . The Corporation has the ability to issue shares from treasury or new shares upon the exercise of stock options or the granting of restricted stock awards. The Board of Directors has authorized management to repurchase shares of the Corporation’s common stock in the market, to be made available for issuance in connection with the Corporation’s employee incentive plans and for other corporate purposes. The repurchase of shares will be based on market and investment opportunities, capital levels, growth prospects,

Investment Securities

Investment Securities	9 Months Ended
	Sep. 30, 2017
Investments, Debt and Equity Securities [Abstract]
Investment Securities	Investment Securities Investment securities are generally classified as available for sale or held to maturity at the time of purchase. The majority of the Corporation's investment securities are mortgage-related securities issued by the Government National Mortgage Association (“GNMA”) or government-sponsored enterprises ("GSE") such as the Federal National Mortgage Association (“FNMA”) and the Federal Home Loan Mortgage Corporation (“FHLMC”). The amortized cost and fair values of securities available for sale and held to maturity were as follows. September 30, 2017 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value ($ in Thousands) Investment securities available for sale U. S. Treasury securities $ 1,003 $ — $ (2 ) $ 1,001 Residential mortgage-related securities FNMA / FHLMC 494,041 12,780 (1,560 ) 505,261 GNMA 1,681,380 2,504 (16,048 ) 1,667,836 Private-label 1,083 — (11 ) 1,072 GNMA commercial mortgage-related securities 1,539,169 73 (26,165 ) 1,513,077 Asset backed securities 108,590 63 (25 ) 108,628 Other securities (debt and equity) 4,718 132 (26 ) 4,824 Total investment securities available for sale $ 3,829,984 $ 15,552 $ (43,837 ) $ 3,801,699 Investment securities held to maturity Obligations of state and political subdivisions (municipal securities) $ 1,192,290 $ 14,525 $ (3,858 ) $ 1,202,957 Residential mortgage-related securities FNMA / FHLMC 42,386 464 (404 ) 42,446 GNMA 444,196 3,712 (2,615 ) 445,293 GNMA commercial mortgage-related securities 554,707 10,250 (11,808 ) 553,149 Total investment securities held to maturity $ 2,233,579 $ 28,951 $ (18,685 ) $ 2,243,845 December 31, 2016 Amortized Gross Gross Fair Value ($ in Thousands) Investment securities available for sale U. S. Treasury securities $ 1,000 $ — $ — $ 1,000 Residential mortgage-related securities FNMA / FHLMC 625,234 17,298 (2,602 ) 639,930 GNMA 2,028,301 1,372 (25,198 ) 2,004,475 Private-label 1,134 1 (14 ) 1,121 GNMA commercial mortgage-related securities 2,064,508 356 (35,966 ) 2,028,898 Other securities (debt and equity) 4,718 105 (21 ) 4,802 Total investment securities available for sale $ 4,724,895 $ 19,132 $ (63,801 ) $ 4,680,226 Investment securities held to maturity Obligations of state and political subdivisions (municipal securities) $ 1,145,843 $ 3,868 $ (12,036 ) $ 1,137,675 Residential mortgage-related securities FNMA / FHLMC 37,697 439 (693 ) 37,443 GNMA 89,996 216 (656 ) 89,556 Total investment securities held to maturity $ 1,273,536 $ 4,523 $ (13,385 ) $ 1,264,674 The amortized cost and fair values of investment securities available for sale and held to maturity at September 30, 2017 , are shown below. Expected maturities will differ from contractual maturities because borrowers may have the right to call or prepay obligations with or without call or prepayment penalties. Available for Sale Held to Maturity Amortized Cost Fair Value Amortized Cost Fair Value ($ in Thousands) Due in one year or less $ 1,000 $ 1,000 $ 54,259 $ 48,123 Due after one year through five years 4,703 4,675 222,037 227,978 Due after five years through ten years — — 281,559 284,789 Due after ten years — — 634,435 642,067 Total debt securities 5,703 5,675 1,192,290 1,202,957 Residential mortgage-related securities FNMA / FHLMC 494,041 505,261 42,386 42,446 GNMA 1,681,380 1,667,836 444,196 445,293 Private-label 1,083 1,072 — — GNMA commercial mortgage-related securities 1,539,169 1,513,077 554,707 553,149 Asset backed securities 108,590 108,628 — — Equity securities 18 150 — — Total investment securities $ 3,829,984 $ 3,801,699 $ 2,233,579 $ 2,243,845 Ratio of Fair Value to Amortized Cost 99.3 % 100.5 % During the nine months ended September 30, 2017 , the Corporation reclassified approximately $1 billion of GNMA residential mortgage-related securities and GNMA commercial mortgage-related securities from available for sale to held to maturity. The GNMA residential and commercial mortgage-related securities are principally securities with a CRA component in the underlying collateral. The reclassification of these investment securities was accounted for at fair value. Management elected to transfer these investment securities as the Corporation has the positive intent and ability to hold these investment securities to maturity. In the third quarter of 2017, the Corporation purchased approximately $109 million of asset backed securities collateralized with government guaranteed student loans. The proceeds from the sale of investment securities for the first nine months ended September 30, 2017 and 2016 are shown below. Nine Months Ended September 30, 2017 2016 ($ in Thousands) Gross gains on available for sale securities $ — $ 6,403 Gross gains on held to maturity securities 364 — Total gains 364 6,403 Gross losses on available for sale securities — (202 ) Gross losses on held to maturity securities (5 ) — Total losses (5 ) (202 ) Investment securities gains, net $ 359 $ 6,201 Proceeds from sales of investment securities $ 16,059 $ 359,591 During the first nine months of 2017, the Corporation sold approximately $16 million of municipal securities classified as held to maturity due to significant credit concerns and negative actions taken by credit rating agencies, primarily as a result of budgetary pressures in the State of Illinois. These sales resulted in a net gain of approximately $359,000 . Investment securities with a carrying value of approximately $2.9 billion and $1.8 billion at September 30, 2017 , and December 31, 2016 , respectively, were pledged to secure certain deposits or for other purposes as required or permitted by law. The following represents gross unrealized losses and the related fair value of investment securities available for sale and held to maturity, aggregated by investment category and length of time individual securities have been in a continuous unrealized loss position, at September 30, 2017 . Less than 12 months 12 months or more Total September 30, 2017 Number of Securities Unrealized Losses Fair Value Number of Securities Unrealized Losses Fair Value Unrealized Losses Fair Value ($ in Thousands) Investment securities available for sale U.S. Treasury securities 1 $ (2 ) $ 1,001 — $ — $ — $ (2 ) $ 1,001 Residential mortgage-related securities FNMA / FHLMC 16 (1,254 ) 177,782 2 (306 ) 33,842 (1,560 ) 211,624 GNMA 22 (9,455 ) 687,814 14 (6,593 ) 378,457 (16,048 ) 1,066,271 Private-label — — — 1 (11 ) 1,072 (11 ) 1,072 GNMA commercial mortgage-related securities 42 (4,962 ) 551,833 56 (21,203 ) 891,178 (26,165 ) 1,443,011 Asset backed securities 5 (25 ) 52,851 — — — (25 ) 52,851 Other securities (debt and equity) 1 (26 ) 174 — — — (26 ) 174 Total 87 $ (15,724 ) $ 1,471,455 73 $ (28,113 ) $ 1,304,549 $ (43,837 ) $ 2,776,004 Investment securities held to maturity Obligations of state and political subdivisions (municipal securities) 195 $ (1,195 ) $ 138,178 108 $ (2,663 ) $ 94,432 $ (3,858 ) $ 232,610 Residential mortgage-related securities FNMA / FHLMC 12 (124 ) 17,816 4 (280 ) 9,910 (404 ) 27,726 GNMA 29 (1,628 ) 223,379 7 (987 ) 67,981 (2,615 ) 291,360 GNMA commercial mortgage-related securities 5 (841 ) 94,758 19 (10,967 ) 427,161 (11,808 ) 521,919 Total 241 $ (3,788 ) $ 474,131 138 $ (14,897 ) $ 599,484 $ (18,685 ) $ 1,073,615 For comparative purposes, the following represents gross unrealized losses and the related fair value of investment securities available for sale and held to maturity, aggregated by investment category and length of time that individual securities have been in a continuous unrealized loss position, at December 31, 2016 . Less than 12 months 12 months or more Total December 31, 2016 Number Unrealized Fair Number Unrealized Fair Unrealized Fair ($ in Thousands) Investment securities available for sale Residential mortgage-related securities FNMA / FHLMC 14 $ (2,602 ) $ 244,252 — $ — $ — $ (2,602 ) $ 244,252 GNMA 54 (25,198 ) 1,723,523 — — — (25,198 ) 1,723,523 Private-label — — — 1 (14 ) 1,119 (14 ) 1,119 GNMA commercial mortgage-related securities 74 (16,445 ) 1,427,889 21 (19,521 ) 429,258 (35,966 ) 1,857,147 Other securities (debt and equity) 3 (21 ) 1,479 — — — (21 ) 1,479 Total 145 $ (44,266 ) $ 3,397,143 22 $ (19,535 ) $ 430,377 $ (63,801 ) $ 3,827,520 Investment securities held to maturity Obligations of state and political subdivisions (municipal securities) 700 $ (11,937 ) $ 414,186 4 $ (99 ) $ 1,752 $ (12,036 ) $ 415,938 Residential mortgage-related securities FNMA / FHLMC 14 (441 ) 17,477 1 (252 ) 6,031 (693 ) 23,508 GNMA 39 (656 ) 64,633 — — — (656 ) 64,633 Total 753 $ (13,034 ) $ 496,296 5 $ (351 ) $ 7,783 $ (13,385 ) $ 504,079 The Corporation reviews the investment securities portfolio on a quarterly basis to monitor its exposure to other-than-temporary impairment. A determination as to whether a security’s decline in fair value is other-than-temporary takes into consideration numerous factors and the relative significance of any single factor can vary by security. Some factors the Corporation may consider in the other-than-temporary impairment analysis include, the length of time and extent to which the security has been in an unrealized loss position, changes in security ratings, financial condition and near-term prospects of the issuer, as well as security and industry specific economic conditions. Based on the Corporation’s evaluation, management does not believe any unrealized loss at September 30, 2017 , represents an other-than-temporary impairment as these unrealized losses are primarily attributable to changes in interest rates and the current market conditions, and not credit deterioration. The unrealized losses reported for municipal securities relate to various state and local political subdivisions and school districts. The Corporation currently does not intend to sell nor does it believe that it will be required to sell the securities contained in the above unrealized losses table before recovery of their amortized cost basis. Federal Home Loan Bank (“FHLB”) and Federal Reserve Bank stocks: The Corporation is required to maintain Federal Reserve stock and FHLB stock as a member of both the Federal Reserve System and the FHLB, and in amounts as required by these institutions. These equity securities are “restricted” in that they can only be sold back to the respective institutions or another member institution at par. Therefore, they are less liquid than other marketable equity securities and their fair value is equal to amortized cost. At September 30, 2017 , and December 31, 2016 , the Corporation had FHLB stock of $97 million and $65 million , respectively. The Corporation had Federal Reserve Bank stock of $76 million and $75 million at September 30, 2017 and December 31, 2016

Loans

Loans	9 Months Ended
	Sep. 30, 2017
Receivables [Abstract]
Loans	Loans The period end loan composition was as follows. September 30, December 31, ($ in Thousands) Commercial and industrial $ 6,534,660 $ 6,489,014 Commercial real estate — owner occupied 827,064 897,724 Commercial and business lending 7,361,724 7,386,738 Commercial real estate — investor 3,345,536 3,574,732 Real estate construction 1,552,135 1,432,497 Commercial real estate lending 4,897,671 5,007,229 Total commercial 12,259,395 12,393,967 Residential mortgage 7,408,471 6,332,327 Home equity 890,130 934,443 Other consumer 373,464 393,979 Total consumer 8,672,065 7,660,749 Total loans $ 20,931,460 $ 20,054,716 The following table presents commercial and consumer loans by credit quality indicator at September 30, 2017 . Pass Special Mention Potential Problem Nonaccrual Total ($ in Thousands) Commercial and industrial $ 6,101,491 $ 157,106 $ 153,779 $ 122,284 $ 6,534,660 Commercial real estate - owner occupied 742,257 11,741 57,468 15,598 827,064 Commercial and business lending 6,843,748 168,847 211,247 137,882 7,361,724 Commercial real estate - investor 3,284,497 10,726 46,770 3,543 3,345,536 Real estate construction 1,550,462 15 118 1,540 1,552,135 Commercial real estate lending 4,834,959 10,741 46,888 5,083 4,897,671 Total commercial 11,678,707 179,588 258,135 142,965 12,259,395 Residential mortgage 7,352,286 881 650 54,654 7,408,471 Home equity 876,003 1,364 124 12,639 890,130 Other consumer 372,638 567 — 259 373,464 Total consumer 8,600,927 2,812 774 67,552 8,672,065 Total $ 20,279,634 $ 182,400 $ 258,909 $ 210,517 $ 20,931,460 The following table presents commercial and consumer loans by credit quality indicator at December 31, 2016 . Pass Special Mention Potential Problem Nonaccrual Total ($ in Thousands) Commercial and industrial $ 5,937,119 $ 141,328 $ 227,196 $ 183,371 $ 6,489,014 Commercial real estate - owner occupied 805,871 17,785 64,524 9,544 897,724 Commercial and business lending 6,742,990 159,113 291,720 192,915 7,386,738 Commercial real estate - investor 3,491,217 14,236 51,228 18,051 3,574,732 Real estate construction 1,429,083 105 2,465 844 1,432,497 Commercial real estate lending 4,920,300 14,341 53,693 18,895 5,007,229 Total commercial 11,663,290 173,454 345,413 211,810 12,393,967 Residential mortgage 6,275,162 1,314 5,615 50,236 6,332,327 Home equity 919,740 1,588 114 13,001 934,443 Other consumer 393,161 562 — 256 393,979 Total consumer 7,588,063 3,464 5,729 63,493 7,660,749 Total $ 19,251,353 $ 176,918 $ 351,142 $ 275,303 $ 20,054,716 Factors that are important to managing overall credit quality are sound loan underwriting and administration, systematic monitoring of existing loans and commitments, effective loan review on an ongoing basis, early identification of potential problems, and appropriate allowance for loan losses, allowance for unfunded commitments, nonaccrual, and charge off policies. For commercial loans, management has determined the pass credit quality indicator to include credits that exhibit acceptable financial statements, cash flow, and leverage. If any risk exists, it is mitigated by the loan structure, collateral, monitoring, or control. For consumer loans, performing loans include credits that are performing in accordance with the original contractual terms. Loans are considered past due if the required principal and interest payments have not been received as of the date such payments were due. Special mention credits have potential weaknesses that deserve management’s attention. If left uncorrected, these potential weaknesses may result in deterioration of the repayment prospects for the credit. Potential problem loans are considered inadequately protected by the current net worth and paying capacity of the obligor or the collateral pledged. These loans generally have a well-defined weakness, or weaknesses, that may jeopardize liquidation of the debt and are characterized by the distinct possibility that the Corporation will sustain some loss if the deficiencies are not corrected. Lastly, management considers a loan to be impaired when it is probable that the Corporation will be unable to collect all amounts due according to the original contractual terms of the note agreement, including both principal and interest. Management has determined that commercial and consumer loan relationships that have nonaccrual status or have had their terms restructured in a troubled debt restructuring meet this impaired loan definition. Commercial loans classified as special mention, potential problem, and nonaccrual are reviewed at a minimum on a quarterly basis, while pass and performing rated credits are reviewed on an annual basis or more frequently if the loan renewal is less than one year or if otherwise warranted. The following table presents loans by past due status at September 30, 2017 . Current 30-59 Days Past Due 60-89 Days Past Due 90 Days or More Past Due (a) Nonaccrual (b) Total ($ in Thousands) Commercial and industrial $ 6,410,690 $ 1,254 $ 124 $ 308 $ 122,284 $ 6,534,660 Commercial real estate - owner occupied 809,944 1,522 — — 15,598 827,064 Commercial and business lending 7,220,634 2,776 124 308 137,882 7,361,724 Commercial real estate - investor 3,340,884 1,109 — — 3,543 3,345,536 Real estate construction 1,549,895 685 15 — 1,540 1,552,135 Commercial real estate lending 4,890,779 1,794 15 — 5,083 4,897,671 Total commercial 12,111,413 4,570 139 308 142,965 12,259,395 Residential mortgage 7,344,947 8,327 543 — 54,654 7,408,471 Home equity 870,300 5,852 1,339 — 12,639 890,130 Other consumer 370,216 987 699 1,303 259 373,464 Total consumer 8,585,463 15,166 2,581 1,303 67,552 8,672,065 Total $ 20,696,876 $ 19,736 $ 2,720 $ 1,611 $ 210,517 $ 20,931,460 (a) The recorded investment in loans past due 90 days or more and still accruing totaled $2 million at September 30, 2017 (the same as the reported balances for the accruing loans noted above). (b) Of the total nonaccrual loans, $156 million or 74% were current with respect to payment at September 30, 2017 . The following table presents loans by past due status at December 31, 2016 . Current 30-59 Days Past Due 60-89 Days Past Due 90 Days or More Past Due (a) Nonaccrual (b) Total ($ in Thousands) Commercial and industrial $ 6,303,994 $ 965 $ 448 $ 236 $ 183,371 $ 6,489,014 Commercial real estate - owner occupied 886,796 968 416 — 9,544 897,724 Commercial and business lending 7,190,790 1,933 864 236 192,915 7,386,738 Commercial real estate - investor 3,555,750 431 500 — 18,051 3,574,732 Real estate construction 1,431,284 264 105 — 844 1,432,497 Commercial real estate lending 4,987,034 695 605 — 18,895 5,007,229 Total commercial 12,177,824 2,628 1,469 236 211,810 12,393,967 Residential mortgage 6,273,949 7,298 844 — 50,236 6,332,327 Home equity 915,593 4,265 1,584 — 13,001 934,443 Other consumer 389,157 2,471 718 1,377 256 393,979 Total consumer 7,578,699 14,034 3,146 1,377 63,493 7,660,749 Total $ 19,756,523 $ 16,662 $ 4,615 $ 1,613 $ 275,303 $ 20,054,716 (a) The recorded investment in loans past due 90 days or more and still accruing totaled $2 million at December 31, 2016 (the same as the reported balances for the accruing loans noted above). (b) Of the total nonaccrual loans, $224 million or 81% were current with respect to payment at December 31, 2016 . The following table presents impaired loans individually evaluated under ASC Topic 310 at September 30, 2017 . Recorded Unpaid Related Average Interest ($ in Thousands) Loans with a related allowance Commercial and industrial $ 67,226 $ 72,343 $ 11,540 $ 76,082 $ 1,050 Commercial real estate — owner occupied 12,255 12,374 1,549 12,032 192 Commercial and business lending 79,481 84,717 13,089 88,114 1,242 Commercial real estate — investor 16,974 16,988 1,812 16,992 1,224 Real estate construction 476 586 75 489 22 Commercial real estate lending 17,450 17,574 1,887 17,481 1,246 Total commercial 96,931 102,291 14,976 105,595 2,488 Residential mortgage 42,684 45,028 6,893 43,090 1,258 Home equity 10,351 11,283 3,684 10,537 411 Other consumer 1,092 1,093 118 1,095 1 Total consumer 54,127 57,404 10,695 54,722 1,670 Total loans (a) $ 151,058 $ 159,695 $ 25,671 $ 160,317 $ 4,158 Loans with no related allowance Commercial and industrial $ 86,802 $ 99,480 $ — $ 100,398 $ 927 Commercial real estate — owner occupied 6,871 7,716 — 7,016 — Commercial and business lending 93,673 107,196 — 107,414 927 Commercial real estate — investor 589 732 — 606 — Real estate construction 213 218 — 220 — Commercial real estate lending 802 950 — 826 — Total commercial 94,475 108,146 — 108,240 927 Residential mortgage 6,469 7,074 — 6,492 105 Home equity 540 543 — 540 — Other consumer — — — — — Total consumer 7,009 7,617 — 7,032 105 Total loans (a) $ 101,484 $ 115,763 $ — $ 115,272 $ 1,032 Total Commercial and industrial $ 154,028 $ 171,823 $ 11,540 $ 176,480 $ 1,977 Commercial real estate — owner occupied 19,126 20,090 1,549 19,048 192 Commercial and business lending 173,154 191,913 13,089 195,528 2,169 Commercial real estate — investor 17,563 17,720 1,812 17,598 1,224 Real estate construction 689 804 75 709 22 Commercial real estate lending 18,252 18,524 1,887 18,307 1,246 Total commercial 191,406 210,437 14,976 213,835 3,415 Residential mortgage 49,153 52,102 6,893 49,582 1,363 Home equity 10,891 11,826 3,684 11,077 411 Other consumer 1,092 1,093 118 1,095 1 Total consumer 61,136 65,021 10,695 61,754 1,775 Total loans (a) $ 252,542 $ 275,458 $ 25,671 $ 275,589 $ 5,190 (a) The net recorded investment (defined as recorded investment, net of the related allowance) of the impaired loans represented 82% of the unpaid principal balance at September 30, 2017 . The following table presents impaired loans individually evaluated under ASC Topic 310 at December 31, 2016 . Recorded Investment Unpaid Principal Balance Related Allowance Average Recorded Investment Interest Income Recognized ($ in Thousands) Loans with a related allowance Commercial and industrial $ 99,786 $ 105,175 $ 21,047 $ 104,808 $ 2,345 Commercial real estate — owner occupied 5,544 5,568 23 5,840 263 Commercial and business lending 105,330 110,743 21,070 110,648 2,608 Commercial real estate — investor 26,764 27,031 3,410 30,665 2,120 Real estate construction 509 648 84 529 31 Commercial real estate lending 27,273 27,679 3,494 31,194 2,151 Total commercial 132,603 138,422 24,564 141,842 4,759 Residential mortgage 37,902 39,979 6,438 38,608 1,551 Home equity 11,070 11,909 3,943 11,420 627 Other consumer 1,012 1,023 109 1,021 2 Total consumer 49,984 52,911 10,490 51,049 2,180 Total loans (a) $ 182,587 $ 191,333 $ 35,054 $ 192,891 $ 6,939 Loans with no related allowance Commercial and industrial $ 113,485 $ 134,863 $ — $ 117,980 $ 1,519 Commercial real estate — owner occupied 8,439 9,266 — 8,759 138 Commercial and business lending 121,924 144,129 — 126,739 1,657 Commercial real estate — investor 6,144 6,478 — 7,092 — Real estate construction — — — — — Commercial real estate lending 6,144 6,478 — 7,092 — Total commercial 128,068 150,607 — 133,831 1,657 Residential mortgage 5,974 6,998 — 6,610 184 Home equity 106 107 — 107 4 Other consumer — — — — — Total consumer 6,080 7,105 — 6,717 188 Total loans (a) $ 134,148 $ 157,712 $ — $ 140,548 $ 1,845 Total Commercial and industrial $ 213,271 $ 240,038 $ 21,047 $ 222,788 $ 3,864 Commercial real estate — owner occupied 13,983 14,834 23 14,599 401 Commercial and business lending 227,254 254,872 21,070 237,387 4,265 Commercial real estate — investor 32,908 33,509 3,410 37,757 2,120 Real estate construction 509 648 84 529 31 Commercial real estate lending 33,417 34,157 3,494 38,286 2,151 Total commercial 260,671 289,029 24,564 275,673 6,416 Residential mortgage 43,876 46,977 6,438 45,218 1,735 Home equity 11,176 12,016 3,943 11,527 631 Other consumer 1,012 1,023 109 1,021 2 Total consumer 56,064 60,016 10,490 57,766 2,368 Total loans (a) $ 316,735 $ 349,045 $ 35,054 $ 333,439 $ 8,784 (a) The net recorded investment (defined as recorded investment, net of the related allowance) of the impaired loans represented 81% of the unpaid principal balance at December 31, 2016 . Troubled Debt Restructurings (“Restructured Loans”) Loans are considered restructured loans if concessions have been granted to borrowers that are experiencing financial difficulty. The Corporation had a recorded investment of approximately $17 million in loans modified in troubled debt restructurings for the nine months ended September 30, 2017 , of which approximately $6 million were in accrual status and $11 million were in nonaccrual pending a sustained period of repayment. The following table presents nonaccrual and performing restructured loans by loan portfolio. September 30, 2017 December 31, 2016 Performing Restructured Loans Nonaccrual Restructured Loans (a) Performing Restructured Loans Nonaccrual Restructured Loans (a) ($ in Thousands) Commercial and industrial $ 32,572 $ 7,994 $ 31,884 $ 1,276 Commercial real estate — owner occupied 4,077 2,145 5,490 2,220 Commercial real estate — investor 14,294 589 15,289 924 Real estate construction 316 160 359 150 Residential mortgage 16,859 20,248 18,100 21,906 Home equity 7,987 2,364 7,756 2,877 Other consumer 1,073 20 979 32 Total $ 77,178 $ 33,520 $ 79,857 $ 29,385 (a) Nonaccrual restructured loans have been included within nonaccrual loans. The following table provides the number of loans modified in a troubled debt restructuring by loan portfolio during the nine months ended September 30, 2017 and 2016 , respectively, and the recorded investment and unpaid principal balance as of September 30, 2017 and 2016 , respectively. Nine Months Ended September 30, 2017 Nine Months Ended September 30, 2016 Number of Loans Recorded Investment (a) Unpaid Principal Balance (b) Number of Loans Recorded Investment (a) Unpaid Principal Balance (b) ($ in Thousands) Commercial and industrial 19 $ 11,387 $ 15,898 10 $ 2,455 $ 2,517 Commercial real estate — owner occupied 2 710 710 1 117 124 Real estate construction — — — 1 66 91 Residential mortgage 48 4,445 4,638 56 4,676 4,922 Home equity 35 934 1,182 47 1,709 1,793 Other consumer — — — 1 15 16 Total 104 $ 17,476 $ 22,428 116 $ 9,038 $ 9,463 (a) Represents post-modification outstanding recorded investment. (b) Represents pre-modification outstanding recorded investment. Restructured loan modifications may include payment schedule modifications, interest rate concessions, maturity date extensions, modification of note structure (A/B Note), non-reaffirmed Chapter 7 bankruptcies, principal reduction, or some combination of these concessions. During the nine months ended September 30, 2017 , restructured loan modifications of commercial and industrial, commercial real estate, and real estate construction loans primarily included maturity date extensions and payment schedule modifications. Restructured loan modifications of home equity and residential mortgage loans primarily included maturity date extensions, interest rate concessions, non-reaffirmed Chapter 7 bankruptcies, or a combination of these concessions for the nine months ended September 30, 2017 . The following table provides the number of loans modified in a troubled debt restructuring during the previous twelve months which subsequently defaulted during the nine months ended September 30, 2017 and 2016 , respectively, as well as the recorded investment in these restructured loans as of September 30, 2017 and 2016 , respectively. Nine Months Ended September 30, 2017 Nine Months Ended September 30, 2016 Number of Loans Recorded Investment Number of Loans Recorded Investment ($ in Thousands) Commercial and industrial 1 $ 1 — $ — Residential mortgage 21 1,335 36 3,310 Home equity 14 371 12 182 Other consumer — — 1 15 Total 36 $ 1,707 49 $ 3,507 All loans modified in a troubled debt restructuring are evaluated for impairment. The nature and extent of the impairment of restructured loans, including those which have experienced a subsequent payment default, is considered in the determination of an appropriate level of the allowance for loan losses. Allowance for Credit Losses The allowance for credit losses is comprised of the allowance for loan losses and the allowance for unfunded commitments. The level of the allowance for loan losses represents management’s estimate of an amount appropriate to provide for probable credit losses in the loan portfolio at the balance sheet date. The allowance for unfunded commitments is maintained at a level believed by management to be sufficient to absorb estimated probable losses related to unfunded credit facilities (including unfunded loan commitments and letters of credit) and is included in accrued expenses and other liabilities on the consolidated balance sheets. See Note 12 for additional information on the allowance for unfunded commitments. The following table presents a summary of the changes in the allowance for loan losses by portfolio segment for the nine months ended September 30, 2017 . ($ in Thousands) Commercial and Commercial real estate Commercial real estate - Real estate Residential Home Other Total December 31, 2016 $ 140,126 $ 14,034 $ 45,285 $ 26,932 $ 27,046 $ 20,364 $ 4,548 $ 278,335 Charge offs (33,928 ) (83 ) (803 ) (225 ) (1,472 ) (2,208 ) (3,238 ) (41,957 ) Recoveries 9,072 158 218 60 754 2,348 563 13,173 Net Charge offs (24,856 ) 75 (585 ) (165 ) (718 ) 140 (2,675 ) (28,784 ) Provision for loan losses 23,587 (4,352 ) 1,798 (1,340 ) 4,632 (479 ) 3,154 27,000 September 30, 2017 $ 138,857 $ 9,757 $ 46,498 $ 25,427 $ 30,960 $ 20,025 $ 5,027 $ 276,551 Allowance for loan losses Individually evaluated for impairment $ 11,540 $ 1,549 $ 1,812 $ 75 $ 6,893 $ 3,684 $ 118 $ 25,671 Collectively evaluated for impairment 127,317 8,208 44,686 25,352 24,067 16,341 4,909 250,880 Total allowance for loan losses $ 138,857 $ 9,757 $ 46,498 $ 25,427 $ 30,960 $ 20,025 $ 5,027 $ 276,551 Loans Individually evaluated for impairment $ 154,028 $ 19,126 $ 17,563 $ 689 $ 49,153 $ 10,891 $ 1,092 $ 252,542 Collectively evaluated for impairment 6,380,632 807,938 3,327,973 1,551,446 7,359,318 879,239 372,372 20,678,918 Total loans $ 6,534,660 $ 827,064 $ 3,345,536 $ 1,552,135 $ 7,408,471 $ 890,130 $ 373,464 $ 20,931,460 For comparison purposes, a summary of the changes in the allowance for loan losses by portfolio segment for the year ended December 31, 2016 , was as follows. ($ in Thousands) Commercial and Commercial real estate Commercial real estate - Real estate Residential Home Other Total December 31, 2015 $ 129,959 $ 18,680 $ 43,018 $ 25,266 $ 28,261 $ 23,555 $ 5,525 $ 274,264 Charge offs (71,016 ) (512 ) (1,504 ) (558 ) (4,332 ) (4,686 ) (3,831 ) (86,439 ) Recoveries 14,543 74 1,624 203 755 3,491 820 21,510 Net Charge offs (56,473 ) (438 ) 120 (355 ) (3,577 ) (1,195 ) (3,011 ) (64,929 ) Provision for loan losses 66,640 (4,208 ) 2,147 2,021 2,362 (1,996 ) 2,034 69,000 December 31, 2016 $ 140,126 $ 14,034 $ 45,285 $ 26,932 $ 27,046 $ 20,364 $ 4,548 $ 278,335 Allowance for loan losses Individually evaluated for impairment $ 21,047 $ 23 $ 3,410 $ 84 $ 6,438 $ 3,943 $ 109 $ 35,054 Collectively evaluated for impairment 119,079 14,011 41,875 26,848 20,608 16,421 4,439 243,281 Total allowance for loan losses $ 140,126 $ 14,034 $ 45,285 $ 26,932 $ 27,046 $ 20,364 $ 4,548 $ 278,335 Loans Individually evaluated for impairment $ 213,271 $ 13,983 $ 32,908 $ 509 $ 43,876 $ 11,176 $ 1,012 $ 316,735 Collectively evaluated for impairment 6,275,743 883,741 3,541,824 1,431,988 6,288,451 923,267 392,967 19,737,981 Total loans $ 6,489,014 $ 897,724 $ 3,574,732 $ 1,432,497 $ 6,332,327 $ 934,443 $ 393,979 $ 20,054,716 At September 30, 2017, the oil and gas portfolio was comprised of 56 credits, totaling $577 million of outstanding balances. The allowance related to the oil and gas portfolio was $30 million at September 30, 2017 and represented 5.2% of total oil and gas loans. ($ in Millions) Nine Months Ended September 30, 2017 Year Ended December 31, 2016 Balance at beginning of period $ 38 $ 42 Charge offs (26 ) (59 ) Recoveries — — Net Charge offs (26 ) (59 ) Provision for loan losses 18 55 Balance at end of period $ 30 $ 38 Allowance for loan losses Individually evaluated for impairment $ 2 $ 14 Collectively evaluated for impairment 28 24 Total allowance for loan losses $ 30 $ 38 Loans Individually evaluated for impairment $ 92 $ 147 Collectively evaluated for impairment 485 521 Total loans $ 577 $ 668 The following table presents a summary of the changes in the allowance for unfunded commitments. Nine Months Ended September 30, 2017 Year Ended December 31, 2016 ($ in Thousands) Allowance for Unfunded Commitments Balance at beginning of period $ 25,400 $ 24,400 Provision for unfunded commitments (1,000 ) 1,000 Balance at end of period $ 24,400 $ 25,400

Goodwill and Other Intangible A

Goodwill and Other Intangible Assets	9 Months Ended
	Sep. 30, 2017
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Intangible Assets	Goodwill and Other Intangible Assets Goodwill Goodwill is not amortized but, instead, is subject to impairment tests on at least an annual basis, and more frequently if an event occurs or circumstances change that would more likely than not reduce the fair value of a reporting unit below its carrying amount. The Corporation conducted its most recent annual impairment testing in May 2017, utilizing a qualitative assessment. Factors that management considered in this assessment included macroeconomic conditions, industry and market considerations, overall financial performance of the Corporation and each reporting unit (both current and projected), changes in management strategy, and changes in the composition or carrying amount of net assets. In addition, management considered the changes in both the Corporation’s common stock price and in the overall bank common stock index (based on the S&P 400 Regional Bank Sub-Industry Index), as well as the Corporation’s earnings per common share trend over the past year. Based on these assessments, management concluded that the 2017 annual qualitative impairment assessment indicated that it is more likely than not that the estimated fair value exceeded the carrying value (including goodwill) for each reporting unit. Therefore, a step one quantitative analysis was not required. There have been no events since the May 2017 impairment testing that have changed the Corporation's impairment assessment conclusion. There were no impairment charges recorded in 2016 or the first nine months of 2017 . At both September 30, 2017 and December 31, 2016 , the Corporation had goodwill of $972 million . Goodwill increased minimally by approximately $55,000 during the first quarter of 2017 as a result of a small insurance acquisition. See Note 2 for additional information on the Corporation's acquisitions. Other Intangible Assets The Corporation has other intangible assets that are amortized, consisting of core deposit intangibles, other intangibles (primarily related to customer relationships acquired in connection with the Corporation’s insurance agency acquisitions), and mortgage servicing rights. During the first quarter of 2017, the Corporation added approximately $162,000 of other intangibles relating to customer relationships associated with one small insurance acquisition. See Note 2 for additional information on the Corporation's acquisitions. During the fist nine months of 2017, core deposit intangibles fully amortized. For core deposit intangibles and other intangibles, changes in the gross carrying amount, accumulated amortization, and net book value were as follows. Nine Months Ended September 30, 2017 Year Ended December 31, 2016 ($ in Thousands) Core deposit intangibles Gross carrying amount $ 4,385 $ 4,385 Accumulated amortization (4,385 ) (4,273 ) Net book value $ — $ 112 Amortization during the year $ 112 $ 281 Other intangibles Gross carrying amount $ 32,572 $ 32,410 Accumulated amortization (18,492 ) (17,145 ) Net book value $ 14,080 $ 15,265 Additions during the period $ 162 $ 1,012 Amortization during the year $ 1,347 $ 1,812 The Corporation sells residential mortgage loans in the secondary market and typically retains the right to service the loans sold. Mortgage servicing rights are amortized in proportion to and over the period of estimated net servicing income and assessed for impairment at each reporting date. The Corporation evaluates its mortgage servicing rights asset for impairment at minimum on a quarterly basis. Impairment is assessed based on fair value at each reporting date using estimated prepayment speeds of the underlying mortgage loans serviced and stratifications based on the risk characteristics of the underlying loans (predominantly loan type and note interest rate). As mortgage interest rates fall, prepayment speeds are usually faster and the value of the mortgage servicing rights asset generally decreases, requiring additional valuation reserve. Conversely, as mortgage interest rates rise, prepayment speeds are usually slower and the value of the mortgage servicing rights asset generally increases, requiring less valuation reserve. A valuation allowance is established, through a charge to earnings, to the extent the amortized cost of the mortgage servicing rights exceeds the estimated fair value by stratification. If it is later determined that all or a portion of the temporary impairment no longer exists for a stratification, the valuation is reduced through a recovery to earnings. An other-than-temporary impairment (i.e., recoverability is considered remote when considering interest rates and loan pay off activity) is recognized as a write-down of the mortgage servicing rights asset and the related valuation allowance (to the extent a valuation allowance is available) and then against earnings. A direct write-down permanently reduces the carrying value of the mortgage servicing rights asset and valuation allowance, precluding subsequent recoveries. See Note 12 for a discussion of the recourse provisions on sold residential mortgage loans. See Note 13 which further discusses fair value measurement relative to the mortgage servicing rights asset. A summary of changes in the balance of the mortgage servicing rights asset and the mortgage servicing rights valuation allowance was as follows. Nine Months Ended September 30, 2017 Year Ended December 31, 2016 ($ in Thousands) Mortgage servicing rights Mortgage servicing rights at beginning of period $ 62,085 $ 62,150 Additions 4,822 12,262 Amortization (7,635 ) (12,327 ) Mortgage servicing rights at end of period $ 59,272 $ 62,085 Valuation allowance at beginning of period (609 ) (809 ) (Additions) recoveries, net (286 ) 200 Valuation allowance at end of period (895 ) (609 ) Mortgage servicing rights, net $ 58,377 $ 61,476 Fair value of mortgage servicing rights $ 62,625 $ 73,149 Portfolio of residential mortgage loans serviced for others (“servicing portfolio”) $ 7,653,458 $ 7,974,742 Mortgage servicing rights, net to servicing portfolio 0.76 % 0.77 % Mortgage servicing rights expense (a) $ 7,921 $ 12,127 (a) Includes the amortization of mortgage servicing rights and additions / recoveries to the valuation allowance of mortgage servicing rights, and is a component of mortgage banking, net in the consolidated statements of income. The following table shows the estimated future amortization expense for amortizing intangible assets. The projections of amortization expense are based on existing asset balances, the current interest rate environment, and prepayment speeds as of September 30, 2017 . The actual amortization expense the Corporation recognizes in any given period may be significantly different depending upon acquisition or sale activities, changes in interest rates, prepayment speeds, market conditions, regulatory requirements, and events or circumstances that indicate the carrying amount of an asset may not be recoverable. Estimated Amortization Expense Other Intangibles Mortgage Servicing Rights ($ in Thousands) Three Months Ended December 31, 2017 $ 451 $ 2,593 2018 1,771 9,337 2019 1,472 7,792 2020 1,355 6,522 2021 1,331 5,484 2022 1,308 4,641 Beyond 2022 6,392 22,903 Total Estimated Amortization Expense $ 14,080 $ 59,272

Short and Long-Term Funding

Short and Long-Term Funding	9 Months Ended
	Sep. 30, 2017
Debt Disclosure [Abstract]
Short and Long-Term Funding	Short and Long-Term Funding The following table presents the components of short-term funding (funding with original contractual maturities of one year or less) and long-term funding (funding with original contractual maturities greater than one year). September 30, 2017 December 31, 2016 ($ in Thousands) Short-Term Funding Federal funds purchased $ 220,575 $ 208,150 Securities sold under agreements to repurchase 255,975 300,197 Federal funds purchased and securities sold under agreements to repurchase $ 476,550 $ 508,347 FHLB advances 520,000 482,000 Commercial paper 68,067 101,688 Other short-term funding 588,067 583,688 Total short-term funding $ 1,064,617 $ 1,092,035 Long-Term Funding FHLB advances $ 2,650,172 $ 2,265,188 Senior notes, at par 250,000 250,000 Subordinated notes, at par 250,000 250,000 Other long-term funding and capitalized costs (2,887 ) (3,393 ) Total long-term funding 3,147,285 2,761,795 Total short and long-term funding $ 4,211,902 $ 3,853,830 Securities Sold Under Agreements to Repurchase ("Repurchase Agreements") The Corporation enters into agreements under which it sells securities subject to an obligation to repurchase the same or similar securities. Under these arrangements, the Corporation may transfer legal control over the assets but still retain effective control through an agreement that both entitles and obligates the Corporation to repurchase the assets. The obligation to repurchase the securities is reflected as a liability on the Corporation’s consolidated balance sheets, while the securities underlying the repurchase agreements remain in the respective investment securities asset accounts (i.e., there is no offsetting or netting of the investment securities assets with the repurchase agreement liabilities). See Note 11 for additional disclosures on balance sheet offsetting. The Corporation utilizes securities sold under agreements to repurchase to facilitate the needs of its customers. As of September 30, 2017 , the Corporation pledged agency mortgage-related securities with a fair value of $391 million as collateral for the repurchase agreements. Securities pledged as collateral under repurchase agreements are maintained with the Corporation's safekeeping agents and are monitored on a daily basis due to the market risk of fair value changes in the underlying securities. The Corporation generally pledges excess securities to ensure there is sufficient collateral to satisfy short-term fluctuations in both the repurchase agreement balances and the fair value of the underlying securities. The remaining contractual maturity of the securities sold under agreements to repurchase in the consolidated balance sheets as of September 30, 2017 and December 31, 2016 are presented in the following table. Remaining Contractual Maturity of the Agreements Overnight and Continuous Up to 30 days 30-90 days Greater than 90 days Total September 30, 2017 ($ in Thousands) Repurchase agreements Agency mortgage-related securities $ 255,975 $ — $ — $ — $ 255,975 Total $ 255,975 $ — $ — $ — $ 255,975 December 31, 2016 Repurchase agreements Agency mortgage-related securities $ 300,197 $ — $ — $ — $ 300,197 Total $ 300,197 $ — $ — $ — $ 300,197 Long-Term Funding FHLB advances: At September 30, 2017 , the long-term FHLB advances had a weighted average interest rate of 1.02% , compared to 0.50% at December 31, 2016 . The majority of FHLB advances are indexed to the FHLB discount note and re-price at varying intervals. The advances offer flexible, low cost, long-term funding that improves the Corporation’s liquidity profile. Senior notes: In November 2014, the Corporation issued $250 million of senior notes, due November 2019, and callable October 2019. The senior notes have a fixed coupon interest rate of 2.75% and were issued at a discount. Subordinated notes: In November 2014, the Corporation issued $250 million of 10 -year subordinated notes, due January 2025, and callable October 2024. The subordinated notes have a fixed coupon interest rate of 4.25%

Derivative and Hedging Activiti

Derivative and Hedging Activities	9 Months Ended
	Sep. 30, 2017
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative and Hedging Activities	Derivative and Hedging Activities The Corporation facilitates customer borrowing activity by providing various interest rate risk management, commodity hedging, and foreign currency exchange solutions through its capital markets area. To date, all of the notional amounts of customer transactions have been matched with a mirror hedge with another counterparty. The Corporation has used, and may use again in the future, derivative instruments to hedge the variability in interest payments or protect the value of certain assets and liabilities recorded on its consolidated balance sheets from changes in interest rates. The predominant derivative and hedging activities include interest rate-related instruments (swaps and caps), foreign currency exchange forwards, commodity contracts, written options, purchased options, and certain mortgage banking activities. The contract or notional amount of a derivative is used to determine, along with the other terms of the derivative, the amounts to be exchanged between the counterparties. The Corporation is exposed to credit risk in the event of nonperformance by counterparties to financial instruments. To mitigate the counterparty risk, interest rate and commodity-related instruments generally contain language outlining collateral pledging requirements for each counterparty. Collateral must be posted when the market value exceeds certain mutually agreed upon threshold limits. The Corporation pledged $26 million of investment securities as collateral at September 30, 2017 , and pledged $40 million of investment securities as collateral at December 31, 2016 . Federal regulations require the Corporation to clear all LIBOR interest rate swaps through a clearing house if it can be cleared. As such, the Corporation is required to pledge cash collateral for the margin. At September 30, 2017 the Corporation posted $3 million of cash collateral for the margin compared to none at December 31, 2016 . Derivatives to Accommodate Customer Needs The Corporation enters into various derivative contracts which are designated as free standing derivative contracts. Free standing derivative products are entered into primarily for the benefit of commercial customers seeking to manage their exposures to interest rate risk, foreign currency, and commodity prices. These derivative contracts are not designated against specific assets and liabilities on the balance sheet or forecasted transactions and, therefore, do not qualify for hedge accounting treatment. Such derivative contracts are carried at fair value on the consolidated balance sheets with changes in the fair value recorded as a component of Capital market fees, net, and typically include interest rate-related instruments (swaps and caps), foreign currency exchange forwards, and commodity contracts. See Note 11 for additional information and disclosures on balance sheet offsetting. Interest rate-related instruments: The Corporation provides interest rate risk management services to commercial customers, primarily forward interest rate swaps and caps. The Corporation’s market risk from unfavorable movements in interest rates related to these derivative contracts is generally economically hedged by concurrently entering into offsetting derivative contracts. The offsetting derivative contracts have identical notional values, terms and indices. Foreign currency exchange forwards: The Corporation provides foreign currency exchange services to customers, primarily forward contracts. Our customers enter into a foreign currency exchange forward with the Corporation as a means for them to mitigate exchange rate risk. The Corporation mitigates its risk by then entering into an offsetting foreign currency exchange derivative contract. Commodity contracts: Commodity contracts are entered into primarily for the benefit of commercial customers seeking to manage their exposure to fluctuating commodity prices. The Corporation mitigates its risk by then entering into an offsetting commodity derivative contract. The table below identifies the balance sheet category and fair values of the Corporation’s free standing derivative instruments, which are not designated as hedging instruments. September 30, 2017 December 31, 2016 ($ in Thousands) Notional Amount Fair Value Balance Sheet Category Notional Amount Fair Balance Sheet Interest rate-related instruments — customer and mirror $ 2,198,794 $ 26,837 Trading assets $ 2,039,323 $ 33,671 Trading assets Interest rate-related instruments — customer and mirror 2,198,794 (26,469 ) Trading liabilities 2,039,323 (33,188 ) Trading liabilities Foreign currency exchange forwards 130,191 3,053 Trading assets 109,675 2,002 Trading assets Foreign currency exchange forwards 122,307 (3,033 ) Trading liabilities 106,251 (1,943 ) Trading liabilities Commodity contracts 424,996 18,539 Trading assets 127,582 16,725 Trading assets Commodity contracts 396,754 (17,310 ) Trading liabilities 128,368 (15,972 ) Trading liabilities Mortgage Derivatives Interest rate lock commitments to originate residential mortgage loans held for sale and forward commitments to sell residential mortgage loans are considered derivative instruments, and the fair value of these commitments is recorded on the consolidated balance sheets with the changes in fair value recorded as a component of mortgage banking, net. Written and Purchased Options (Time Deposit) Historically, the Corporation had entered into written and purchased option derivative instruments to facilitate an equity linked time deposit product (the “Power CD”), which the Corporation ceased offering in September 2013. The Power CD was a time deposit that provided the purchaser a guaranteed return of principal at maturity plus a potential equity return (a written option), while the Corporation received a known stream of funds based on the equity return (a purchased option). The written and purchased options are mirror derivative instruments, which are carried at fair value on the consolidated balance sheets. The table below identifies the balance sheet category and fair values of the Corporation’s derivative instruments, which are not designated as hedging instruments. September 30, 2017 December 31, 2016 ($ in Thousands) Notional Amount Fair Balance Sheet Notional Amount Fair Balance Sheet Interest rate lock commitments (mortgage) $ 354,075 $ 2,729 Other assets $ 285,345 $ 206 Other assets Forward commitments (mortgage) 243,500 234 Other assets 179,600 2,908 Other assets Purchased options (time deposit) 53,074 1,434 Other assets 80,554 2,576 Other assets Written options (time deposit) 53,074 (1,434 ) Other liabilities 80,554 (2,576 ) Other liabilities The table below identifies the income statement category of the gains and losses recognized in income on the Corporation’s derivative instruments not designated as hedging instruments. Income Statement Category of Gain / (Loss) Recognized in Income Nine Months Ended September 30, ($ in Thousands) 2017 2016 Derivative Instruments Interest rate-related instruments — customer and mirror, net Capital market fees, net $ (115 ) $ (888 ) Interest rate lock commitments (mortgage) Mortgage banking, net 2,523 2,768 Forward commitments (mortgage) Mortgage banking, net (2,674 ) (2,271 ) Foreign currency exchange forwards Capital market fees, net (39 ) (85 ) Commodity contracts Capital market fees, net 476 690

Balance Sheet Offsetting

Balance Sheet Offsetting	9 Months Ended
	Sep. 30, 2017
Offsetting [Abstract]
Balance Sheet Offsetting	Balance Sheet Offsetting Interest Rate-Related Instruments and Commodity Contracts (“Interest and Commodity Agreements”) The Corporation enters into interest rate-related instruments to facilitate the interest rate risk management strategies of commercial customers. The Corporation also enters into commodity contracts to manage commercial customers' exposure to fluctuating commodity prices. The Corporation mitigates these risks by entering into equal and offsetting interest and commodity agreements with highly rated third party financial institutions. The Corporation is party to master netting arrangements with its financial institution counterparties that creates a single net settlement of all legal claims or obligations to pay or receive the net amount of settlement of the individual interest and commodity agreements. Collateral, usually in the form of investment securities and cash, is posted by the counterparty with net liability positions in accordance with contract thresholds. The Corporation does not offset assets and liabilities under these arrangements for financial statement presentation purposes. See Note 10 for additional information on the Corporation’s derivative and hedging activities. Securities Sold Under Agreements to Repurchase (“Repurchase Agreements”) The Corporation enters into agreements under which it sells securities subject to an obligation to repurchase the same or similar securities. These repurchase agreements are accounted for as collateralized financing arrangements (i.e., secured borrowings) and not as a sale and subsequent repurchase of securities (i.e., there is no offsetting or netting of the investment securities assets with the repurchase agreement liabilities). The right of set-off for a repurchase agreement resembles a secured borrowing, whereby the collateral would be used to settle the fair value of the repurchase agreement should the Corporation be in default (e.g., fails to make an interest payment to the counterparty). In addition, the Corporation does not enter into reverse repurchase agreements; therefore, there is no such offsetting to be done with the repurchase agreements. See Note 9 for additional disclosures on repurchase agreements. The following table presents the assets and liabilities subject to an enforceable master netting arrangement. The interest and commodity agreements we have with our commercial customers are not subject to an enforceable master netting arrangement, and therefore, are excluded from this table. Gross amounts recognized Gross amounts not offset in the balance sheet Gross amounts offset in the balance sheet Net amounts presented in the balance sheet Financial instruments Collateral Net amount ($ in Thousands) September 30, 2017 Derivative assets Interest and commodity agreements $ 23,224 $ — $ 23,224 $ (21,783 ) $ (1,441 ) $ — Derivative liabilities Interest and commodity agreements $ 21,783 $ — $ 21,783 $ (21,783 ) $ — $ — December 31, 2016 Derivative assets Interest and commodity agreements $ 18,031 $ — $ 18,031 $ (18,031 ) $ — $ — Derivative liabilities Interest and commodity agreements $ 31,075 $ — $ 31,075 $ (18,031 ) $ (11,148 ) $ 1,896

Commitments, Off-Balance Sheet

Commitments, Off-Balance Sheet Arrangements, Legal Proceedings and Regulatory Matters	9 Months Ended
	Sep. 30, 2017
Commitments and Contingencies Disclosure [Abstract]
Commitments, Off-Balance Sheet Arrangements, and Legal Proceedings	Commitments, Off-Balance Sheet Arrangements, Legal Proceedings and Regulatory Matters The Corporation utilizes a variety of financial instruments in the normal course of business to meet the financial needs of its customers and to manage its own exposure to fluctuations in interest rates. These financial instruments include lending-related and other commitments (see below) as well as derivative instruments (see Note 10 ). The following is a summary of lending-related commitments. September 30, 2017 December 31, 2016 ($ in Thousands) Commitments to extend credit, excluding commitments to originate residential mortgage loans held for sale (a)(b) $ 8,002,766 $ 8,131,131 Commercial letters of credit (a) 8,961 7,923 Standby letters of credit (c) 233,783 259,632 (a) These off-balance sheet financial instruments are exercisable at the market rate prevailing at the date the underlying transaction will be completed and, thus, are deemed to have no current fair value, or the fair value is based on fees currently charged to enter into similar agreements and is not material at September 30, 2017 or December 31, 2016 . (b) Interest rate lock commitments to originate residential mortgage loans held for sale are considered derivative instruments and are disclosed in Note 10 . (c) The Corporation has established a liability of $2 million at September 30, 2017 and $3 million at December 31, 2016 , as an estimate of the fair value of these financial instruments. Lending-related Commitments As a financial services provider, the Corporation routinely enters into commitments to extend credit. Such commitments are subject to the same credit policies and approval process accorded to loans made by the Corporation, with each customer’s creditworthiness evaluated on a case-by-case basis. The commitments generally have fixed expiration dates or other termination clauses and may require the payment of a fee. The Corporation’s exposure to credit loss in the event of nonperformance by the other party to these financial instruments is represented by the contractual amount of those instruments. The amount of collateral obtained, if deemed necessary by the Corporation upon extension of credit, is based on management’s credit evaluation of the customer. Since a significant portion of commitments to extend credit are subject to specific restrictive loan covenants or may expire without being drawn upon, the total commitment amounts do not necessarily represent future cash flow requirements. An allowance for unfunded commitments is maintained at a level believed by management to be sufficient to absorb estimated probable losses related to unfunded commitments (including unfunded loan commitments and letters of credit). The allowance for unfunded commitments totaled $24 million at September 30, 2017 and $25 million at December 31, 2016 , and is included in accrued expenses and other liabilities on the consolidated balance sheets. Lending-related commitments include commitments to extend credit, commitments to originate residential mortgage loans held for sale, commercial letters of credit, and standby letters of credit. Commitments to extend credit are legally binding agreements to lend to customers at predetermined interest rates, as long as there is no violation of any condition established in the contracts. Interest rate lock commitments to originate residential mortgage loans held for sale and forward commitments to sell residential mortgage loans are considered derivative instruments, and the fair value of these commitments is recorded on the consolidated balance sheets. The Corporation’s derivative and hedging activity is further described in Note 10 . Commercial and standby letters of credit are conditional commitments issued to guarantee the performance of a customer to a third party. Commercial letters of credit are issued specifically to facilitate commerce and typically result in the commitment being drawn on when the underlying transaction is consummated between the customer and the third party, while standby letters of credit generally are contingent upon the failure of the customer to perform according to the terms of the underlying contract with the third party. Other Commitments The Corporation has principal investment commitments to provide capital-based financing to private and public companies through either direct investments in specific companies or through investment funds and partnerships. The timing of future cash requirements to fund such commitments is generally dependent on the investment cycle, whereby privately held companies are funded by private equity investors and ultimately sold, merged, or taken public through an initial offering, which can vary based on overall market conditions, as well as the nature and type of industry in which the companies operate. The Corporation also invests in unconsolidated projects including low-income housing, new market tax credit projects, and historic tax credit projects to promote the revitalization of primarily low-to-moderate-income neighborhoods throughout the local communities of its bank subsidiary. As a limited partner in these unconsolidated projects, the Corporation is allocated tax credits and deductions associated with the underlying projects. The aggregate carrying value of these investments at September 30, 2017 , was $142 million , compared to $85 million at December 31, 2016 , included in other assets on the consolidated balance sheets. Related to these investments, the Corporation had remaining commitments to fund of $101 million at September 30, 2017 , and $69 million at December 31, 2016 . Legal Proceedings The Corporation is party to various pending and threatened claims and legal proceedings arising in the normal course of business activities, some of which involve claims for substantial amounts. Although there can be no assurance as to the ultimate outcomes, the Corporation believes it has meritorious defenses to the claims asserted against it in its currently outstanding matters, including the matters described below, and with respect to such legal proceedings, intends to continue to defend itself vigorously. The Corporation will consider settlement of cases when, in management’s judgment, it is in the best interests of both the Corporation and its shareholders. On at least a quarterly basis, the Corporation assesses its liabilities and contingencies in connection with all pending or threatened claims and litigation, utilizing the most recent information available. On a matter by matter basis, an accrual for loss is established for those matters which the Corporation believes it is probable that a loss may be incurred and that the amount of such loss can be reasonably estimated. Once established, each accrual is adjusted as appropriate to reflect any subsequent developments. Accordingly, management’s estimate will change from time to time, and actual losses may be more or less than the current estimate. For matters where a loss is not probable, or the amount of the loss cannot be estimated, no accrual is established. Resolution of legal claims is inherently unpredictable, and in many legal proceedings various factors exacerbate this inherent unpredictability, including where the damages sought are unsubstantiated or indeterminate, it is unclear whether a case brought as a class action will be allowed to proceed on that basis, discovery is not complete, the proceeding is not yet in its final stages, the matters present legal uncertainties, there are significant facts in dispute, there are a large number of parties (including where it is uncertain how liability, if any, will be shared among multiple defendants), or there is a wide range of potential results. A lawsuit, R.J. ZAYED v. Associated Bank, N.A. , was filed in the United States District Court for the District of Minnesota on January 29, 2013. The lawsuit relates to a Ponzi scheme perpetrated by Oxford Global Partners and related entities (“Oxford”) and individuals and was brought by the receiver for Oxford. Oxford was a depository customer of Associated Bank (the "Bank"). The lawsuit claims that the Bank is liable for failing to uncover the Oxford Ponzi scheme, and specifically alleges the Bank aided and abetted (1) the fraudulent scheme; (2) a breach of fiduciary duty; (3) conversion; and (4) false representations and omissions. The lawsuit seeks unspecified consequential and punitive damages. The District Court granted the Bank’s motion to dismiss the complaint on September 30, 2013. On March 2, 2015, the U.S. Court of Appeals for the Eighth Circuit reversed the District Court and remanded the case back to the District Court for further proceedings. On January 31, 2017, the District Court granted the Bank’s motion for summary judgment. The receiver has appealed the District Court’s summary judgment decision to the Eighth Circuit Court of Appeals. It is not possible for management to assess the probability of a material adverse outcome or reasonably estimate the amount of any potential loss at this time. A lawsuit by investors in the same Ponzi scheme, Herman Grad, et al v. Associated Bank, N.A., brought in Brown County, Wisconsin in October 2009 was dismissed by the circuit court, and the dismissal was affirmed by the Wisconsin Court of Appeals in June 2011 in an unpublished opinion. Two complaints were filed against the Bank on January 11, 2016 in the United States Bankruptcy Court for the Northern District of Illinois, Eastern Division in connection with the In re: World Marketing Chicago, LLC, et al Chapter 11 bankruptcy proceeding. In the first complaint, The Official Committee of Unsecured Creditors of World Marketing Chicago, LLC, et al v. Associated Bank, N.A., the plaintiff seeks to avoid guarantees and pledges of collateral given by the debtors to secure a revolving financing commitment of $6 million to the debtors’ parent company from the Bank. The plaintiff alleges a variety of legal theories under federal and state law, including fraudulent conveyance, preferential transfer and conversion, in support of its position. The plaintiff seeks return of approximately $4 million paid to the Bank and the avoidance of the security interest in the collateral securing the remaining indebtedness to the Bank. The Bank intends to vigorously defend this lawsuit. In the second complaint, American Funds Service Company v. Associated Bank, N.A., the plaintiff alleges that approximately $600,000 of funds it had advanced to the World Marketing entities to apply towards future postage fees was swept by the Bank from World Marketing’s bank accounts. Plaintiff seeks the return of such funds from the Bank under several theories, including Sec. 541(d) of the Bankruptcy Code, the creation of a resulting trust, and unjust enrichment. The Bank intends to vigorously defend this lawsuit. It is not possible for management to assess the probability of a material adverse outcome or reasonably estimate the amount of any potential loss at this time with respect to these two lawsuits. Subsequent to the announcement on July 20, 2017, of the Merger Agreement between the Corporation and Bank Mutual, several lawsuits were filed in connection with the proposed merger. On July 28, 2017, two substantially identical purported class action complaints, each by various individual plaintiffs, were filed with the Wisconsin Circuit Court for Milwaukee County on behalf of the respective named plaintiffs and other Bank Mutual shareholders against Bank Mutual, the members of the Bank Mutual board, and the Corporation. The lawsuits are captioned Schumel et al v. Bank Mutual Corporation et al. and Paquin et al. v. Bank Mutual Corporation et al . Both complaints allege state law breach of fiduciary duty claims against the Bank Mutual board for, among other things, seeking to sell Bank Mutual through an allegedly defective process, for an allegedly unfair price and on allegedly unfair terms. On August 30, 2017, a third purported class action complaint, captioned Wollenburg et al. v. Bank Mutual Corporation et al ., was filed in the Wisconsin Circuit Court for Milwaukee County, on behalf of the same class of shareholders and against the same defendants as the prior two complaints. The Wollenburg complaint asserts similar allegations as the prior two complaints, and further alleges that the preliminary proxy statement/prospectus filed with the SEC contains various alleged misstatements or omissions under federal securities law. The Paquin , Schumel and Wollenburg complaints allege that the Corporation aided and abetted Bank Mutual's directors' alleged breaches of fiduciary duty. The parties have entered into a stipulation seeking to consolidate the three actions. On September 13, 2017, the Corporation filed a notice of removal of the Paquin , Schumel and Wollenburg actions to the United States District Court for the Eastern District of Wisconsin. On September 15, 2017, the plaintiffs in the Paquin , Schumel and Wollenburg actions filed identical motions to remand the three cases back to state court, and on September 27, 2017, the defendants filed oppositions to the motions to remand. On October 3, 2017, the defendants filed motions to dismiss the three actions. On September 6, 2017, a fourth purported class action complaint, captioned Parshall et al., v. Bank Mutual Corporation et al ., was filed in the U.S. District Court for the Eastern District of Wisconsin, on behalf of the same class of shareholders and against the same defendants as the prior complaints. The Parshall complaint criticizes the adequacy of the merger consideration and alleges that Bank Mutual, the members of the Bank Mutual board and the Corporation allegedly omitted and/or misrepresented certain information in the registration statement on Form S-4 filed in connection with the proposed merger in violation of the federal securities laws. The lawsuits seek, among other things, to enjoin the consummation of the transaction and damages. The Corporation believes the allegations are without merit. On October 13, 2017, Bank Mutual and the Corporation reached agreement with the plaintiffs in each of the four cases whereby Bank Mutual issued certain additional disclosures in a Form 8-K, and each of the plaintiffs have agreed to dismiss their actions with prejudice as to the named plaintiffs and without prejudice as to the rest of the purported class members. Regulatory Matters On May 22, 2015, the Bank entered into a Conciliation Agreement ("Conciliation Agreement") with the U.S. Department of Housing and Urban Development ("HUD") which resolved the HUD investigation into the Bank's lending practices during the years 2008-2010. The Bank's commitments under the Conciliation Agreement are spread over a three -year period and include commitments to do the following in minority communities: make mortgage loans of approximately $196 million ; open one branch and four loan production offices; establish special financing programs; make affordable home repair grants; engage in affirmative marketing outreach; provide financial education programs; and make grants to support community reinvestment training and education. The cost of these commitments will be spread over four calendar years and is not expected to have a material impact on the Corporation's financial condition or results of operation. Beginning in late 2013, the Corporation began reviewing a variety of legacy products provided by third parties, including debt protection and identity protection products. In connection with this review, the Corporation has made remediation payments to affected customers and former customers, and has reserved accordingly. A variety of consumer products, including the legacy debt protection and identity protection products referred to above, and mortgage and deposit products, and certain fees and charges related to such products, have come under increased regulatory scrutiny. It is possible that regulatory authorities could bring enforcement actions, including civil money penalties, or take other actions against the Corporation and the Bank in regard to these consumer products. The Bank could also determine of its own accord, or be required by regulators, to refund or otherwise make remediation payments to customers in connection with these products. It is not possible at this time for management to assess the probability of a material adverse outcome or reasonably estimate the amount of any potential loss related to such matters. On March 27, 2017, the Bank received a Community Reinvestment Act ("CRA") rating from the Office of the Comptroller of the Currency of "Satisfactory" for the period from January 1, 2011 through July 27, 2015. As a result of this rating, the restrictions on certain of the Bank's activities that had been imposed under the previous "Needs to Improve" CRA rating are no longer applicable. Mortgage Repurchase Reserve The Corporation sells residential mortgage loans to investors in the normal course of business. Residential mortgage loans sold to others are predominantly conventional residential first lien mortgages originated under our usual underwriting procedures, and are most often sold on a nonrecourse basis, primarily to the GSEs. The Corporation’s agreements to sell residential mortgage loans in the normal course of business usually require certain representations and warranties on the underlying loans sold, related to credit information, loan documentation, collateral, and insurability. Subsequent to being sold, if a material underwriting deficiency or documentation defect is discovered, the Corporation may be obligated to repurchase the loan or reimburse the GSEs for losses incurred (collectively, “make whole requests”). The make whole requests and any related risk of loss under the representations and warranties are largely driven by borrower performance. As a result of make whole requests, the Corporation has repurchased loans with principal balances of approximately $1 million and $2 million during the nine months ended September 30, 2017 and the year ended December 31, 2016 , respectively. The loss reimbursement and settlement claims paid for both the nine months ended September 30, 2017 and the year ended December 31, 2016 were negligible. Make whole requests during 2016 and the first nine months of 2017 generally arose from loans sold during the period of January 1, 2012 to September 30, 2017 , which totaled $9.7 billion at the time of sale, and consisted primarily of loans sold to GSEs. As of September 30, 2017 , approximately $6.1 billion of these sold loans remain outstanding. The balance in the mortgage repurchase reserve at the balance sheet date reflects the estimated amount of potential loss the Corporation could incur from repurchasing a loan, as well as loss reimbursements, indemnifications, and other settlement resolutions. The following summarizes the changes in the mortgage repurchase reserve. Nine Months Ended September 30, 2017 Year Ended December 31, 2016 ($ in Thousands) Balance at beginning of period $ 900 $ 1,197 Repurchase provision expense 165 456 Adjustments to provision expense — (750 ) Charge offs, net (148 ) (3 ) Balance at end of period $ 917 $ 900 The Corporation may also sell residential mortgage loans with limited recourse (limited in that the recourse period ends prior to the loan’s maturity, usually after certain time and / or loan paydown criteria have been met), whereby repurchase could be required if the loan had defined delinquency issues during the limited recourse periods. At September 30, 2017 , and December 31, 2016 , there were approximately $77 million and $62 million , respectively, of residential mortgage loans sold with such recourse risk. There have been limited instances and immaterial historical losses on repurchases for recourse under the limited recourse criteria. The Corporation has a subordinate position to the FHLB in the credit risk on residential mortgage loans it sold to the FHLB in exchange for a monthly credit enhancement fee. The Corporation has not sold loans to the FHLB with such credit risk retention since February 2005. At September 30, 2017 and December 31, 2016 , there were $79 million and $98 million

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2017
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements Fair value represents the estimated price at which an orderly transaction to sell an asset or to transfer a liability would take place between market participants at the measurement date under current market conditions (i.e., an exit price concept). Assets and Liabilities Measured at Fair Value on a Recurring Basis Following is a description of the valuation methodologies used for the Corporation’s more significant instruments measured on a recurring basis at fair value, including the general classification of such instruments pursuant to the valuation hierarchy. Investment securities available for sale: Where quoted prices are available in an active market, investment securities are classified in Level 1 of the fair value hierarchy. If quoted market prices are not available for the specific security, then fair values are estimated by using pricing models, quoted prices of securities with similar characteristics or discounted cash flows, with consideration given to the nature of the quote and the relationship of recently evidenced market activity to the fair value estimate, and are classified in Level 2 of the fair value hierarchy. Lastly, in certain cases where there is limited activity or less transparency around inputs to the estimated fair value, securities are classified within Level 3 of the fair value hierarchy. To validate the fair value estimates, assumptions, and controls, the Corporation looks to transactions for similar instruments and utilizes independent pricing provided by third party vendors or brokers and relevant market indices. While none of these sources are solely indicative of fair value, they serve as directional indicators for the appropriateness of the Corporation’s fair value estimates. The Corporation has determined that the fair value measures of its investment securities are classified predominantly within Level 1 or 2 of the fair value hierarchy. See Note 6 for additional disclosure regarding the Corporation’s investment securities. Residential loans held for sale: Loans held for sale, which consist generally of current production of certain fixed-rate, first-lien residential mortgage loans, are now carried at estimated fair value. Effective January 1, 2017, management elected the fair value option to account for all newly originated mortgage loans held for sale which results in the financial impact of changing market conditions being reflected currently in earnings as opposed to being dependent upon the timing of sales. Therefore, the continually adjusted values going forward will better reflect the price the Corporation expects to receive from the sale of such loans. The estimated fair value was based on what secondary markets are currently offering for portfolios with similar characteristics, which the Corporation classifies as a Level 2 fair value measurement. Derivative financial instruments (interest rate-related instruments): The Corporation has used, and may use again in the future, interest rate swaps to manage its interest rate risk. In addition, the Corporation offers interest rate-related instruments (swaps and caps) to service our customers’ needs, for which the Corporation simultaneously enters into offsetting derivative financial instruments (i.e., mirror interest rate-related instruments) with third parties to manage its interest rate risk associated with these financial instruments. The valuation of the Corporation’s derivative financial instruments is determined using discounted cash flow analysis on the expected cash flows of each derivative and, also includes a nonperformance / credit risk component (credit valuation adjustment). See Note 10 for additional disclosure regarding the Corporation’s interest rate-related instruments. The discounted cash flow analysis component in the fair value measurements reflects the contractual terms of the derivative financial instruments, including the period to maturity, and uses observable market-based inputs, including interest rate curves and implied volatilities. More specifically, the fair values of interest rate swaps are determined using the market standard methodology of netting the discounted future fixed cash receipts (or payments), with the variable cash payments (or receipts) based on an expectation of future interest rates (forward curves) derived from observable market interest rate curves. Likewise, the fair values of interest rate options (i.e., interest rate caps) are determined using the market standard methodology of discounting the future expected cash receipts that would occur if variable interest rates fall below (or rise above) the strike rate of the floors (or caps), with the variable interest rates used in the calculation of projected receipts on the floor (or cap) based on an expectation of future interest rates derived from observable market interest rate curves and volatilities. The Corporation also incorporates credit valuation adjustments to appropriately reflect both its own nonperformance risk and the respective counterparty’s nonperformance risk in the fair value measurements. In adjusting the fair value of its derivative financial instruments for the effect of nonperformance risk, the Corporation has considered the impact of netting and any applicable credit enhancements, such as collateral postings, thresholds, mutual puts, and guarantees. While the Corporation has determined that the majority of the inputs used to value its derivative financial instruments fall within Level 2 of the fair value hierarchy, the credit valuation adjustments utilize Level 3 inputs, such as estimates of current credit spreads to evaluate the likelihood of default by itself and its counterparties. The Corporation has assessed the significance of the impact of the credit valuation adjustments on the overall valuation of its derivative positions as of September 30, 2017 , and December 31, 2016 , and has determined that the credit valuation adjustments are not significant to the overall valuation of its derivative financial instruments. Therefore, the Corporation has determined that the fair value measures of its derivative financial instruments in their entirety are classified within Level 2 of the fair value hierarchy. Derivative financial instruments (foreign currency exchange forwards): The Corporation provides foreign currency exchange services to customers. In addition, the Corporation may enter into a foreign currency exchange forward to mitigate the exchange rate risk attached to the cash flows of a loan or as an offsetting contract to a forward entered into as a service to our customer. The valuation of the Corporation’s foreign currency exchange forwards is determined using quoted prices of foreign currency exchange forwards with similar characteristics, with consideration given to the nature of the quote and the relationship of recently evidenced market activity to the fair value estimate, and are classified in Level 2 of the fair value hierarchy. See Note 10 for additional disclosures regarding the Corporation’s foreign currency exchange forwards. Derivative financial instruments (commodity contracts): The Corporation enters into commodity contracts to manage commercial customers' exposure to fluctuating commodity prices, for which the Corporation simultaneously enters into offsetting derivative financial instruments (i.e., mirror commodity contracts) with third parties to manage its risk associated with these financial instruments. The valuation of the Corporation’s commodity contracts is determined using quoted prices of the underlying instruments, and are classified in Level 2 of the fair value hierarchy. See Note 10 for additional disclosures regarding the Corporation’s commodity contracts. The table below presents the Corporation’s financial instruments measured at fair value on a recurring basis as of September 30, 2017 and December 31, 2016 , aggregated by the level in the fair value hierarchy within which those measurements fall. Fair Value Hierarchy September 30, 2017 December 31, 2016 ($ in Thousands) Assets Investment securities available for sale: U.S. Treasury securities Level 1 $ 1,001 $ 1,000 Residential mortgage-related securities: FNMA / FHLMC Level 2 505,261 639,930 GNMA Level 2 1,667,836 2,004,475 Private-label Level 2 1,072 1,121 GNMA commercial mortgage-related securities Level 2 1,513,077 2,028,898 Asset backed securities Level 2 108,628 — Other securities (debt and equity) Level 1 1,650 1,602 Other securities (debt and equity) Level 2 3,174 3,000 Other securities (debt and equity) Level 3 — 200 Total investment securities available for sale Level 1 2,651 2,602 Total investment securities available for sale Level 2 3,799,048 4,677,424 Total investment securities available for sale Level 3 — 200 Residential loans held for sale (a) Level 2 113,064 — Interest rate-related instruments Level 2 26,837 33,671 Foreign currency exchange forwards Level 2 3,053 2,002 Interest rate lock commitments to originate residential mortgage loans held for sale Level 3 2,729 206 Forward commitments to sell residential mortgage loans Level 3 234 2,908 Commodity contracts Level 2 18,539 16,725 Purchased options (time deposit) Level 2 1,434 2,576 Liabilities Interest rate-related instruments Level 2 $ 26,469 $ 33,188 Foreign currency exchange forwards Level 2 3,033 1,943 Commodity contracts Level 2 17,310 15,972 Written options (time deposit) Level 2 1,434 2,576 (a) Effective January 1, 2017, residential loans originated for sale are accounted for under the fair value option. Prior periods have not been restated. For more information on this accounting policy change, please refer to Note 3. The table below presents a rollforward of the balance sheet amounts for the nine months ended September 30, 2017 and the year ended December 31, 2016 , for financial instruments measured on a recurring basis and classified within Level 3 of the fair value hierarchy. Investment Securities Available for Sale Derivative Financial Instruments ($ in Thousands) Balance December 31, 2015 $ 200 $ 1,361 Total net gains included in income Mortgage derivative gain — 1,753 Balance December 31, 2016 $ 200 $ 3,114 Total net losses included in income Mortgage derivative loss — (151 ) Transfer out of level 3 securities (a) (200 ) — Balance September 30, 2017 $ — $ 2,963 (a) During the first quarter of 2017, the $200,000 level 3 investment security was transferred to level 2 based upon new pricing information. For Level 3 assets and liabilities measured at fair value on a recurring basis as of September 30, 2017 , the Corporation utilized the following valuation techniques and significant unobservable inputs. Derivative financial instruments (mortgage derivative — interest rate lock commitments to originate residential mortgage loans held for sale): The fair value is determined by the change in value from each loan’s rate lock date to the expected rate lock expiration date based on the underlying loan attributes, estimated closing ratios, and investor price matrix determined to be reasonably applicable to each loan commitment. The closing ratio calculation takes into consideration historical experience and loan-level attributes, particularly the change in the current interest rates from the time of initial rate lock. The closing ratio is periodically reviewed for reasonableness and reported to the Associated Mortgage Risk Management Committee. At September 30, 2017 , the closing ratio was 87% . Derivative financial instruments (mortgage derivative—forward commitments to sell mortgage loans): Mortgage derivatives include forward commitments to deliver closed end residential mortgage loans into conforming Agency Mortgage Backed Securities (To be Announced, "TBA") or conforming Cash Forward sales. The fair value of such instruments is determined by the difference of current market prices for such traded instruments or available from forward cash delivery commitments and the original traded price for such commitments. The Corporation also relies on an internal valuation model to estimate the fair value of its forward commitments to sell residential mortgage loans (i.e., an estimate of what the Corporation would receive or pay to terminate the forward delivery contract based on market prices for similar financial instruments), which includes matching specific terms and maturities of the forward commitments against applicable investor pricing available. While there are Level 2 and 3 inputs used in the valuation models, the Corporation has determined that the majority of the inputs significant in the valuation of both of the mortgage derivatives fall within Level 3 of the fair value hierarchy. See Note 10 for additional disclosure regarding the Corporation’s mortgage derivatives. Assets and Liabilities Measured at Fair Value on a Nonrecurring Basis Following is a description of the valuation methodologies used for the Corporation’s more significant instruments measured on a nonrecurring basis at the lower of amortized cost or estimated fair value, including the general classification of such instruments pursuant to the valuation hierarchy. Commercial loans held for sale: Loans held for sale are carried at the lower of cost or estimated fair value. The estimated fair value is based on a discounted cash flow analysis, which the Corporation classifies as a Level 2 nonrecurring fair value measurement. Other real estate owned: Certain other real estate owned, upon initial recognition, was re-measured and reported at fair value through a charge off to the allowance for loan losses based upon the estimated fair value of the other real estate owned, less estimated selling costs. The fair value of other real estate owned, upon initial recognition or subsequent impairment, was estimated using appraised values, which the Corporation classifies as a Level 2 nonrecurring fair value measurement. For Level 3, assets and liabilities measured at fair value on a nonrecurring basis as of September 30, 2017 , the Corporation utilized the following valuation techniques and significant unobservable inputs. Impaired loans: The Corporation considers a loan impaired when it is probable that the Corporation will be unable to collect all amounts due according to the original contractual terms of the note agreement, including both principal and interest. Management has determined that commercial and consumer loan relationships that have nonaccrual status or have had their terms restructured in a troubled debt restructuring meet this impaired loan definition. For individually evaluated impaired loans, the amount of impairment is based upon the present value of expected future cash flows discounted at the loan’s effective interest rate, the estimated fair value of the underlying collateral for collateral-dependent loans, or the estimated liquidity of the note. See Note 7 for additional information regarding the Corporation’s impaired loans. Mortgage servicing rights: Mortgage servicing rights do not trade in an active, open market with readily observable prices. While sales of mortgage servicing rights do occur, the precise terms and conditions typically are not readily available to allow for a “quoted price for similar assets” comparison. Accordingly, the Corporation utilizes an independent valuation from a third party which uses a discounted cash flow model to estimate the fair value of its mortgage servicing rights. The valuation model incorporates prepayment assumptions to project mortgage servicing rights cash flows based on the current interest rate scenario, which is then discounted to estimate an expected fair value of the mortgage servicing rights. The valuation model considers portfolio characteristics of the underlying mortgages, contractually specified servicing fees, prepayment assumptions, discount rate assumptions, delinquency rates, late charges, other ancillary revenue, costs to service, and other economic factors. The Corporation periodically reviews and assesses the underlying inputs and assumptions used in the model. In addition, the Corporation compares its fair value estimates and assumptions to observable market data for mortgage servicing rights, where available, and to recent market activity and actual portfolio experience. Due to the nature of the valuation inputs, mortgage servicing rights are classified within Level 3 of the fair value hierarchy. The Corporation uses the amortization method (i.e., lower of amortized cost or estimated fair value measured on a nonrecurring basis), not fair value measurement accounting, for its mortgage servicing rights assets. The discounted cash flow analyses that generate expected market prices utilize the observable characteristics of the mortgage servicing rights portfolio, as well as certain unobservable valuation parameters. The significant unobservable inputs used in the fair value measurement of the Corporation’s mortgage servicing rights are the weighted average constant prepayment rate and weighted average discount rate. Significant increases (decreases) in any of those inputs in isolation could result in a significantly lower (higher) fair value measurement. These parameter assumptions fall within a range that the Corporation, in consultation with an independent third party, believes purchasers of servicing would apply to such portfolios sold into the current secondary servicing market. Discussions are held with members from Treasury and the Community, Consumer, and Business segment to reconcile the fair value estimates and the key assumptions used by the respective parties in arriving at those estimates. The Associated Mortgage Risk Management Committee is responsible for providing control over the valuation methodology and key assumptions. To assess the reasonableness of the fair value measurement, the Corporation also compares the fair value and constant prepayment rate to a value calculated by an independent third party on an annual basis. See Note 8 for additional disclosure regarding the Corporation’s mortgage servicing rights. The table below presents the Corporation’s assets measured at fair value on a nonrecurring basis, aggregated by the level in the fair value hierarchy within which those measurements fall. Income Statement Category of Adjustment Recognized in Income ($ in Thousands) Fair Value Hierarchy Fair Value September 30, 2017 Assets Commercial loans held for sale (a) Level 2 $ 9,718 Provision for credit losses $ — Impaired loans (c) Level 3 54,762 Provision for credit losses (d) (22,703 ) Other real estate owned Level 2 3,291 Foreclosure / OREO expense, net (939 ) Mortgage servicing rights Level 3 62,625 Mortgage banking, net (286 ) December 31, 2016 Assets Commercial loans held for sale Level 2 $ 12,474 Provision for credit losses $ (559 ) Residential loans held for sale (b) Level 2 108,010 Mortgage banking, net (3,760 ) Impaired loans (c) Level 3 79,270 Provision for credit losses (d) (75,194 ) Other real estate owned Level 2 9,752 Foreclosure / OREO expense, net (1,091 ) Mortgage servicing rights Level 3 73,149 Mortgage banking, net 200 (a) Commercial loans held for sale are carried at the lower of cost or estimated fair value. At September 30, 2017 , the estimated fair value exceeded the cost and therefore there was no adjustment recognized in income. (b) Effective January 1, 2017, residential loans originated for sale are accounted for under the fair value option. Prior periods have not been restated. For more information on this accounting policy change, please refer to Note 3. (c) Represents individually evaluated impaired loans, net of the related allowance for loan losses. (d) Represents provision for credit losses on individually evaluated impaired loans. The change in provision for credit loss is primarily due to the oil and gas portfolio. For more information on the oil and gas portfolio, see Note 7 . Certain nonfinancial assets and nonfinancial liabilities measured at fair value on a nonrecurring basis include the fair value analysis in the second step of a goodwill impairment test, and intangible assets and other nonfinancial long-lived assets measured at fair value for impairment assessment. The Corporations's significant Level 3 measurements which employ unobservable inputs that are readily quantifiable pertain to mortgage servicing rights and impaired loans. The table below presents information about these inputs and further discussion is found above. Valuation Technique Significant Unobservable Input Weighted Average Input Applied September 30, 2017 Mortgage servicing rights Discounted cash flow Discount rate 11% Mortgage servicing rights Discounted cash flow Constant prepayment rate 12% Impaired Loans Appraisals / Discounted cash flow Collateral / Discount factor 16% Fair Value of Financial Instruments The Corporation is required to disclose estimated fair values for its financial instruments. Fair value estimates, methods, and assumptions are set forth below for the Corporation’s financial instruments. September 30, 2017 December 31, 2016 Fair Value Hierarchy Level Carrying Amount Fair Value Carrying Amount Fair Value ($ in Thousands) Financial assets Cash and due from banks Level 1 $ 354,331 $ 354,331 $ 446,558 $ 446,558 Interest-bearing deposits in other financial institutions Level 1 109,596 109,596 149,175 149,175 Federal funds sold and securities purchased under agreements to resell Level 1 27,700 27,700 46,500 46,500 Investment securities held to maturity Level 2 2,233,579 2,243,845 1,273,536 1,264,674 Investment securities available for sale Level 1 2,651 2,651 2,602 2,602 Investment securities available for sale Level 2 3,799,048 3,799,048 4,677,424 4,677,424 Investment securities available for sale Level 3 — — 200 200 FHLB and Federal Reserve Bank stocks Level 2 172,446 172,446 140,001 140,001 Commercial loans held for sale Level 2 9,718 9,718 12,474 12,474 Residential loans held for sale Level 2 113,064 113,064 108,010 108,010 Loans, net Level 3 20,654,909 20,504,971 19,776,381 19,680,317 Bank and corporate owned life insurance Level 2 589,093 589,093 585,290 585,290 Derivatives (trading and other assets) Level 2 49,863 49,863 54,974 54,974 Derivatives (trading and other assets) Level 3 2,963 2,963 3,114 3,114 Financial liabilities Noninterest-bearing demand, savings, interest-bearing demand, and money market accounts Level 3 $ 20,012,174 $ 20,012,174 $ 20,282,321 $ 20,282,321 Brokered CDs and other time deposits Level 2 2,321,277 2,321,277 1,606,127 1,606,127 Short-term funding Level 2 1,064,617 1,064,617 1,092,035 1,092,035 Long-term funding Level 2 3,147,285 3,171,059 2,761,795 2,791,841 Standby letters of credit (a) Level 2 2,346 2,346 2,566 2,566 Derivatives (trading and other liabilities) Level 2 48,246 48,246 53,679 53,679 (a) The commitment on standby letters of credit was $234 million and $260 million at September 30, 2017 and December 31, 2016 , respectively. See Note 12 for additional information on the standby letters of credit and for information on the fair value of lending-related commitments. Cash and due from banks, interest-bearing deposits in other financial institutions, and federal funds sold and securities purchased under agreements to resell: For these short-term instruments, the carrying amount is a reasonable estimate of fair value. Investment securities (held to maturity and available for sale): The fair value of investment securities is based on quoted prices in active markets, or if quoted prices are not available for a specific security, then fair values are estimated by using pricing models, quoted prices of securities with similar characteristics, or discounted cash flows. FHLB and Federal Reserve Bank stocks: The carrying amount is a reasonable fair value estimate for the Federal Reserve Bank and FHLB stocks given their “restricted” nature (i.e., the stock can only be sold back to the respective institutions (FHLB or Federal Reserve Bank) or another member institution at par). Loans held for sale: The fair value estimation process for the loans held for sale portfolio is segregated by loan type. The estimated fair value for residential loans held for sale was based on what secondary markets are currently offering for portfolios with similar characteristics. The estimated fair value for commercial loans held for sale was based on a discounted cash flow analysis. Loans, net: The fair value estimation process for the loan portfolio uses an exit price concept and reflects discounts the Corporation believes are consistent with liquidity discounts in the market place. Fair values are estimated for portfolios of loans with similar financial characteristics. Loans are segregated by type such as commercial and industrial, real estate construction, commercial real estate (owner occupied and investor), residential mortgage, home equity, and other consumer. The fair value of loans is estimated by discounting the future cash flows using the current rates at which similar loans would be made to borrowers with similar credit ratings and for similar maturities. The fair value analysis also included other assumptions to estimate fair value, intended to approximate those a market participant would use in an orderly transaction, with adjustments for discount rates, interest rates, liquidity, and credit spreads, as appropriate. Bank and corporate owned life insurance ("BOLI" and "COLI"): The fair value of BOLI and COLI approximates the carrying amount, because upon liquidation of these investments, the Corporation would receive the cash surrender value which equals the carrying amount. The Corporation has not purchased any new BOLI or COLI policies since 2008. Deposits: The fair value of deposits with no stated maturity such as noninterest-bearing demand, savings, interest-bearing demand, and money market accounts, is equal to the amount payable on demand as of the balance sheet date. The fair value of Brokered CDs and other time deposits is based on the discounted value of contractual cash flows. The discount rate is estimated using the rates currently offered for deposits of similar remaining maturities. However, if the estimated fair value of Brokered CDs and other time deposits is less than the carrying value, the carrying value is reported as the fair value. Short-term funding: The carrying amount is a reasonable estimate of fair value for existing short-term funding. Long-term funding: Rates currently available to the Corporation for debt with similar terms and remaining maturities are used to estimate the fair value of existing long-term funding. Standby letters of credit: The fair value of standby letters of credit represents deferred fees arising from the related off-balance sheet financial instruments. These deferred fees approximate the fair value of these instruments and are based on several factors, including the remaining terms of the agreement and the credit standing of the customer. Derivatives (trading and other): A detailed description of the Corporation's derivative instruments can be found under the "Assets and Liabilities Measured at Fair Value on a Recurring Basis" section of this footnote. Limitations:

Retirement Plans

Retirement Plans	9 Months Ended
	Sep. 30, 2017
Defined Benefit Plan [Abstract]
Retirement Plans	Retirement Plans The Corporation has a noncontributory defined benefit retirement plan (the Retirement Account Plan (“RAP”)) covering substantially all employees who meet participation requirements. The benefits are based primarily on years of service and the employee’s compensation paid. Employees of acquired entities generally participate in the RAP after consummation of the business combinations. Any retirement plans of acquired entities are typically merged into the RAP after completion of the mergers, and credit is usually given to employees for years of service at the acquired institution for vesting and eligibility purposes. The Corporation also provides legacy healthcare access to a limited group of retired employees from a previous acquisition in the Postretirement Plan. There are no other active retiree healthcare plans. The components of net periodic benefit cost for the RAP and Postretirement Plan for three and nine months ended September 30, 2017 and 2016 were as follows. Three Months Ended September 30, Nine Months Ended September 30, 2017 2016 2017 2016 ($ in Thousands) Components of Net Periodic Benefit Cost RAP Service cost $ 1,713 $ 1,636 $ 5,276 $ 5,086 Interest cost 1,795 1,781 5,307 5,341 Expected return on plan assets (4,929 ) (5,085 ) (14,692 ) (15,215 ) Amortization of prior service cost (19 ) (80 ) (56 ) (55 ) Amortization of actuarial loss 619 621 1,594 1,586 Total net pension cost $ (821 ) $ (1,127 ) $ (2,571 ) $ (3,257 ) Postretirement Plan Interest cost $ 26 $ 35 $ 74 $ 107 Amortization of prior service cost (19 ) — (57 ) — Amortization of actuarial loss 2 — 2 — Total net periodic benefit cost $ 9 $ 35 $ 19 $ 107 The Corporation’s funding policy is to pay at least the minimum amount required by federal law and regulations, with consideration given to the maximum funding amounts allowed. The Corporation regularly reviews the funding of its RAP. The Corporation made contributions of $6 million

Segment Reporting

Segment Reporting	9 Months Ended
	Sep. 30, 2017
Segment Reporting [Abstract]
Segment Reporting	Segment Reporting The Corporation utilizes a risk-based internal profitability measurement system to provide strategic business unit reporting. The profitability measurement system is based on internal management methodologies designed to produce consistent results and reflect the underlying economics of the units. Certain strategic business units have been combined for segment information reporting purposes where the nature of the products and services, the type of customer and the distribution of those products and services are similar. The three reportable segments are Corporate and Commercial Specialty; Community, Consumer, and Business; and Risk Management and Shared Services. The financial information of the Corporation’s segments has been compiled utilizing the accounting policies described in the Corporation’s 2016 Annual Report on Form 10-K, with certain exceptions. The more significant of these exceptions are described herein. The Corporation allocates net interest income using an internal funds transfer pricing ("FTP") methodology that charges users of funds (assets) and credits providers of funds (liabilities, primarily deposits) based on the maturity, prepayment and / or repricing characteristics of the assets and liabilities. The net effect of this allocation is recorded in the Risk Management and Shared Services segment. A credit provision is allocated to segments based on the expected long-term annual net charge off rates attributable to the credit risk of loans managed by the segment during the period. In contrast, the level of the consolidated provision for credit losses is determined based on an incurred loss model using the methodologies described in the Corporation’s 2016 Annual Report on Form 10-K to assess the overall appropriateness of the allowance for loan losses. The net effect of the credit provision is recorded in Risk Management and Shared Services. Indirect expenses incurred by certain centralized support areas are allocated to segments based on actual usage (for example, volume measurements) and other criteria. Certain types of administrative expense and bank- wide expense accruals (including amortization of core deposit and other intangible assets associated with acquisitions) are generally not allocated to segments. Income taxes are allocated to segments based on the Corporation’s estimated effective tax rate, with certain segments adjusted for any tax-exempt income or non-deductible expenses. Equity is allocated to the segments based on regulatory capital requirements and in proportion to an assessment of the inherent risks associated with the business of the segment (including interest, credit and operating risk). The management accounting policies and processes utilized in compiling segment financial information are highly subjective and, unlike financial accounting, are not based on authoritative guidance similar to U.S. generally accepted accounting principles. As a result, reported segments and the financial information of the reported segments are not necessarily comparable with similar information reported by other financial institutions. Furthermore, changes in management structure or allocation methodologies and procedures may result in changes in previously reported segment financial data. A brief description of each business segment is presented below. A more in-depth discussion of these segments can be found in the Segment Reporting footnote in the Corporation’s 2016 Annual Report on Form 10-K. The Corporate and Commercial Specialty segment serves a wide range of customers including larger businesses, developers, not-for-profits, municipalities, and financial institutions. The Community, Consumer, and Business segment serves individuals, as well as small and mid-sized businesses. The Risk Management and Shared Services segment includes key shared operational functions and also includes residual revenue and expenses, representing the difference between actual amounts incurred and the amounts allocated to operating segments, including interest rate risk residuals (FTP mismatches) and credit risk and provision residuals (long-term credit charge mismatches). Segment Income Statement Data ($ in Thousands) Corporate and Community, Risk Management Consolidated Nine Months Ended September 30, 2017 Net interest income $ 271,615 $ 270,011 $ 12,589 $ 554,215 Noninterest income 36,768 198,546 12,822 248,136 Total revenue 308,383 468,557 25,411 802,351 Credit provision (a) 32,549 15,317 (21,866 ) 26,000 Noninterest expense 116,578 361,580 49,276 527,434 Income (loss) before income taxes 159,256 91,660 (1,999 ) 248,917 Income tax expense (benefit) 53,082 32,081 (15,500 ) 69,663 Net income $ 106,174 $ 59,579 $ 13,501 $ 179,254 Return on average allocated capital (ROCET1) (b) 12.7 % 13.6 % 2.2 % 11.0 % Nine Months Ended September 30, 2016 Net interest income $ 242,800 $ 257,848 $ 26,590 $ 527,238 Noninterest income 35,172 207,460 17,962 260,594 Total revenue 277,972 465,308 44,552 787,832 Credit provision (a) 38,933 18,357 (2,290 ) 55,000 Noninterest expense 109,511 370,714 43,420 523,645 Income (loss) before income taxes 129,528 76,237 3,422 209,187 Income tax expense (benefit) 42,623 26,683 (5,560 ) 63,746 Net income $ 86,905 $ 49,554 $ 8,982 $ 145,441 Return on average allocated capital (ROCET1) (b) 10.9 % 10.5 % 1.4 % 9.7 % Segment Balance Sheet Data ($ in Thousands) Corporate and Community, Risk Management Consolidated Average balances for YTD September 2017 Average earning assets $ 10,846,418 $ 9,418,173 $ 6,587,401 $ 26,851,992 Average loans 10,837,933 9,414,880 248,165 20,500,978 Average deposits 6,759,105 11,568,220 3,486,354 21,813,679 Average allocated capital (CET1) (b) $ 1,121,800 $ 584,774 $ 387,388 $ 2,093,962 Average balances for YTD September 2016 Average earning assets $ 10,097,995 $ 9,287,158 $ 6,508,356 $ 25,893,509 Average loans 10,088,777 9,285,848 166,447 19,541,072 Average deposits 5,906,695 11,320,106 3,531,614 20,758,415 Average allocated capital (CET1) (b) $ 1,063,598 $ 631,484 $ 225,813 $ 1,920,895 (a) The consolidated credit provision is equal to the actual reported provision for credit losses. (b) Segment Income Statement Data ($ in Thousands) Corporate and Commercial Specialty Community, Consumer, and Business Risk Management and Shared Services Consolidated Total Three Months Ended September 30, 2017 Net interest income $ 92,356 $ 90,952 $ 6,814 $ 190,122 Noninterest income 12,278 67,867 5,750 85,895 Total revenue 104,634 158,819 12,564 276,017 Credit provision (a) 9,499 5,046 (9,545 ) 5,000 Noninterest expense 39,681 120,241 17,505 177,427 Income (loss) before income taxes 55,454 33,532 4,604 93,590 Income tax expense (benefit) 19,070 11,736 (2,217 ) 28,589 Net income $ 36,384 $ 21,796 $ 6,821 $ 65,001 Return on average allocated capital (ROCET1) (b) 12.8 % 14.7 % 4.4 % 11.7 % Three Months Ended September 30, 2016 Net interest income $ 83,567 $ 87,274 $ 7,693 $ 178,534 Noninterest income 12,623 78,580 4,031 95,234 Total revenue 96,190 165,854 11,724 273,768 Credit provision (a) 11,080 5,969 3,951 21,000 Noninterest expense 37,968 127,454 9,892 175,314 Income (loss) before income taxes 47,142 32,431 (2,119 ) 77,454 Income tax expense (benefit) 14,907 11,351 (2,620 ) 23,638 Net income $ 32,235 $ 21,080 $ 501 $ 53,816 Return on average allocated capital (ROCET1) (b) 11.7 % 13.2 % (2.9 )% 10.5 % Segment Balance Sheet Data ($ in Thousands) Corporate and Commercial Specialty Community, Consumer, and Business Risk Management and Shared Services Consolidated Total Three Months Ended September 30, 2017 Average earning assets $ 10,923,762 $ 9,608,242 $ 6,927,791 $ 27,459,795 Average loans 10,916,829 9,602,098 380,210 20,899,137 Average deposits 7,398,970 11,788,606 3,253,869 22,441,445 Average allocated capital (CET1) (b) $ 1,125,181 $ 588,841 $ 405,653 $ 2,119,675 Three Months Ended September 30, 2016 Average earning assets $ 10,441,454 $ 9,414,718 $ 6,577,991 $ 26,434,163 Average loans 10,435,341 9,413,401 204,034 20,052,776 Average deposits 6,227,305 11,526,639 3,650,081 21,404,025 Average allocated capital (CET1) (b) $ 1,091,624 $ 633,392 $ 227,600 $ 1,952,616 (a) The consolidated credit provision is equal to the actual reported provision for credit losses. (b)

Accumulated Other Comprehensive

Accumulated Other Comprehensive Income (Loss)	9 Months Ended
	Sep. 30, 2017
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Accumulated Other Comprehensive Income (Loss)	Accumulated Other Comprehensive Income (Loss) The following tables summarize the components, changes, and reclassifications from accumulated other comprehensive income (loss) for the nine months and three months ended September 30, 2017 and 2016, respectively. ($ in Thousands) Investment Securities Available For Sale Defined Benefit Pension and Post Retirement Obligations Accumulated Other Comprehensive Income (Loss) Balance January 1, 2017 $ (20,079 ) $ (34,600 ) $ (54,679 ) Other comprehensive income (loss) before reclassifications 1,646 — 1,646 Amounts reclassified from accumulated other comprehensive income (loss) Personnel expense — 1,483 1,483 Interest income (amortization of net unrealized losses (gains) on available for sale securities transferred to held to maturity securities) (2,499 ) — (2,499 ) Income tax (expense) benefit 328 (567 ) (239 ) Net other comprehensive income (loss) during period (525 ) 916 391 Balance September 30, 2017 $ (20,604 ) $ (33,684 ) $ (54,288 ) Balance January 1, 2016 $ 459 $ (33,075 ) $ (32,616 ) Other comprehensive income (loss) before reclassifications 59,849 — 59,849 Amounts reclassified from accumulated other comprehensive income (loss) Investment securities gain (loss), net (6,201 ) — (6,201 ) Personnel expense — 1,531 1,531 Interest income (amortization of net unrealized losses (gains) on available for sale securities transferred to held to maturity securities) (4,465 ) — (4,465 ) Income tax (expense) benefit (18,768 ) (584 ) (19,352 ) Net other comprehensive income (loss) during period 30,415 947 31,362 Balance September 30, 2016 $ 30,874 $ (32,128 ) $ (1,254 ) Investment Defined Benefit Accumulated Balance July 1, 2017 $ (19,428 ) $ (34,042 ) $ (53,470 ) Other comprehensive income (loss) before reclassifications (1,986 ) — (1,986 ) Amounts reclassified from accumulated other comprehensive income (loss) Personnel expense — 583 583 Interest income (amortization of net unrealized losses (gains) on available for sale securities transferred to held to maturity securities) 76 — 76 Income tax (expense) benefit 734 (225 ) 509 Net other comprehensive income (loss) during period (1,176 ) 358 (818 ) Balance September 30, 2017 $ (20,604 ) $ (33,684 ) $ (54,288 ) Balance July 1, 2016 $ 45,916 $ (32,463 ) $ 13,453 Other comprehensive income (loss) before reclassifications (22,894 ) — (22,894 ) Amounts reclassified from accumulated other comprehensive income (loss) Investment securities gain (loss), net 13 — 13 Personnel expense — 541 541 Interest income (amortization of net unrealized losses (gains) on available for sale securities transferred to held to maturity securities) (1,441 ) — (1,441 ) Income tax (expense) benefit 9,280 (206 ) 9,074 Net other comprehensive income (loss) during period (15,042 ) 335 (14,707 ) Balance September 30, 2016 $ 30,874 $ (32,128 ) $ (1,254 )

Summary of Significant Accoun25

Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2017
New Accounting Pronouncements and Changes in Accounting Principles [Abstract]
Finance, Loan and Lease Receivables, Held-for-sale, Policy	Accounting Policy Elections Effective January 1, 2017, residential mortgage loans that are classified as held for sale are accounted using the fair value option method of accounting. The Corporation has elected the fair value option to mitigate accounting mismatches between held for sale loan valuations and corresponding derivative commitments. Prior to January 1, 2017,
New Accounting Pronouncements, Policy	New Accounting Pronouncements Adopted Standard Description Date of adoption Effect on financial statements ASU 2017-08 Receivables - Nonrefundable Fees and Other Costs (Subtopic 310-20), Premium Amortization on Purchased Callable Debt Securities The FASB issued amendments to require that certain purchased callable debt securities held at a premium be amortized to the earliest call date. The amendments do not require an accounting change for securities held at a discount, which continue to be amortized to maturity. 1st Quarter 2017 The Corporation early adopted the accounting standard with no material impact on results of operations, financial position, or liquidity. ASU 2017-03 Accounting Changes and Error Corrections (Topic 250) and Investments - Equity Method and Joint Ventures (Topic 323) The standard states that for ASUs which have not been adopted yet, the registrant needs to determine the potential effects (if material) of those ASUs on the financial statements when adopted and include the appropriate disclosures in the financial statements. If the impact of adoption is unknown or cannot be estimated, the registrant should include a statement noting this and consider adding qualitative disclosures to the financial statements to assist the reader in evaluating the impact of the ASUs, when adopted, on the financial statements. 1st Quarter 2017 No material impact on results of operations, financial position, or liquidity. ASU 2016-17 Consolidation (Topic 810): Interests Held through Related Parties That Are Under Common Control The FASB issued an amendment to address how a reporting entity that is a single decision maker of a variable interest entity treats indirect interests in the entity held through related parties that are under common control with the reporting entity. 1st Quarter 2017 No material impact on results of operations, financial position, or liquidity. ASU 2016-09 Compensation - Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting The FASB issued an amendment involving several aspects of the accounting for share-based payment transactions, including the income tax consequences, classification of awards as either equity or liabilities, and classification on the statement of cash flows. Entities should apply the amendment related to the timing of when excess tax benefits are recognized, minimum statutory withholding requirements, forfeitures, and intrinsic value using a modified retrospective transition method by means of a cumulative-effect adjustment to equity as of the beginning of the period in which the guidance is adopted. Entities should apply the amendment related to the presentation of employee taxes paid on the statement of cash flows when an employer withholds shares to meet the minimum statutory withholding requirement retrospectively. The amendment requiring recognition of excess tax benefits and tax deficiencies in the income statement and the practical expedient for estimating expected term should be applied prospectively. 4th Quarter 2016 The Corporation early adopted the accounting standard and recognized a $1 million reduction in income taxes for the excess tax benefits on stock-based compensation. The remaining provisions of this accounting standard did not have a material impact on the results of operations, financial position, or liquidity. ASU 2016-07 Investments - Equity Method and Joint Ventures (Topic 323): Simplifying the Transition to the Equity Method of Accounting The FASB issued an amendment to eliminate the requirement that when an investment qualifies for use of the equity method as a result of an increase in the level of ownership interest or degree of influence, an investor must adjust the investment, results of operations, and retained earnings retroactively on a step-by-step basis as if the equity method had been in effect during all previous periods that the investment had been held. The amendment requires that the equity method investor add the cost of acquiring the additional interests in the investee to the current basis of the investor’s previously held interest and adopt the equity method of accounting as of the date the investment becomes qualified for equity method accounting. Therefore, upon qualifying for the equity method of accounting, no retroactive adjustment of the investment is required. The amendment requires that an entity that has an available-for-sale equity security that becomes qualified for the equity method of accounting recognize through earnings the unrealized holding gain or loss in accumulated other comprehensive income at the date the investment becomes qualified for use of the equity method. Entities should apply the amendment prospectively to increases in the level of ownership interest or degree of influence that result in the adoption of the equity method. 1st Quarter 2017 No material impact on results of operations, financial position, or liquidity.

Earnings Per Common Share (Tabl

Earnings Per Common Share (Tables)	9 Months Ended
	Sep. 30, 2017
Earnings Per Share [Abstract]
Calculations for basic and diluted earnings per common share	Presented below are the calculations for basic and diluted earnings per common share. For the Three Months Ended September 30, For the Nine Months Ended September 30, 2017 2016 2017 2016 (In thousands, except per share data) Net income $ 65,001 $ 53,816 $ 179,254 $ 145,441 Preferred stock dividends (2,339 ) (2,188 ) (7,008 ) (6,555 ) Net income available to common equity $ 62,662 $ 51,628 $ 172,246 $ 138,886 Common shareholder dividends (18,149 ) (16,431 ) (54,726 ) (49,077 ) Unvested share-based payment awards (105 ) (177 ) (332 ) (565 ) Undistributed earnings $ 44,408 $ 35,020 $ 117,188 $ 89,244 Undistributed earnings allocated to common shareholders 44,150 34,645 116,418 88,294 Undistributed earnings allocated to unvested share-based payment awards 258 375 770 950 Undistributed earnings $ 44,408 $ 35,020 $ 117,188 $ 89,244 Basic Distributed earnings to common shareholders $ 18,149 $ 16,431 $ 54,726 $ 49,077 Undistributed earnings allocated to common shareholders 44,150 34,645 116,418 88,294 Total common shareholders earnings, basic $ 62,299 $ 51,076 $ 171,144 $ 137,371 Diluted Distributed earnings to common shareholders $ 18,149 $ 16,431 $ 54,726 $ 49,077 Undistributed earnings allocated to common shareholders 44,150 34,645 116,418 88,294 Total common shareholders earnings, diluted $ 62,299 $ 51,076 $ 171,144 $ 137,371 Weighted average common shares outstanding 150,565 148,708 150,983 148,607 Effect of dilutive common stock awards 1,815 1,265 2,081 1,038 Effect of dilutive common stock warrants 588 — 718 — Diluted weighted average common shares outstanding 152,968 149,973 153,782 149,645 Basic earnings per common share $ 0.41 $ 0.34 $ 1.13 $ 0.92 Diluted earnings per common share $ 0.41 $ 0.34 $ 1.11 $ 0.92

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	9 Months Ended
	Sep. 30, 2017
Retirement Benefits [Abstract]
Fair value assumptions of stock options	The following assumptions were used in estimating the fair value for options granted in the first nine months of 2017 and full year 2016 . 2017 2016 Dividend yield 2.00 % 2.50 % Risk-free interest rate 2.00 % 2.00 % Weighted average expected volatility 25.00 % 25.00 % Weighted average expected life 5.5 years 5.5 years Weighted average per share fair value of options $5.30 $3.36
Summary of Company's Stock Option Activities	A summary of the Corporation’s stock option activity for the nine months ended September 30, 2017 is presented below. Stock Options Shares Weighted Average Exercise Price Weighted Average Remaining Contractual Term Aggregate Intrinsic Value (a) Outstanding at December 31, 2016 6,357,843 $ 17.67 6.10 $ 47,902 Granted 799,558 25.61 Exercised (1,291,244 ) 16.32 Forfeited or expired (506,395 ) 31.90 Outstanding at September 30, 2017 5,359,762 $ 18.07 6.55 $ 34,334 Options Exercisable at September 30, 2017 3,072,811 $ 16.54 5.25 $ 23,911
Summary of Restricted Stock Awards Activity (Excluding Salary Shares)	The following table summarizes information about the Corporation’s restricted stock activity for the nine months ended September 30, 2017 . Restricted Stock Shares Weighted Average Grant Date Fair Value Outstanding at December 31, 2016 2,377,380 $ 17.40 Granted 748,024 25.55 Vested (872,020 ) 17.92 Forfeited (101,703 ) 20.02 Outstanding at September 30, 2017 2,151,681 $ 19.94

Investment Securities (Tables)

Investment Securities (Tables)	9 Months Ended
	Sep. 30, 2017
Investments, Debt and Equity Securities [Abstract]
Investment securities available for sale	The amortized cost and fair values of securities available for sale and held to maturity were as follows. September 30, 2017 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value ($ in Thousands) Investment securities available for sale U. S. Treasury securities $ 1,003 $ — $ (2 ) $ 1,001 Residential mortgage-related securities FNMA / FHLMC 494,041 12,780 (1,560 ) 505,261 GNMA 1,681,380 2,504 (16,048 ) 1,667,836 Private-label 1,083 — (11 ) 1,072 GNMA commercial mortgage-related securities 1,539,169 73 (26,165 ) 1,513,077 Asset backed securities 108,590 63 (25 ) 108,628 Other securities (debt and equity) 4,718 132 (26 ) 4,824 Total investment securities available for sale $ 3,829,984 $ 15,552 $ (43,837 ) $ 3,801,699 Investment securities held to maturity Obligations of state and political subdivisions (municipal securities) $ 1,192,290 $ 14,525 $ (3,858 ) $ 1,202,957 Residential mortgage-related securities FNMA / FHLMC 42,386 464 (404 ) 42,446 GNMA 444,196 3,712 (2,615 ) 445,293 GNMA commercial mortgage-related securities 554,707 10,250 (11,808 ) 553,149 Total investment securities held to maturity $ 2,233,579 $ 28,951 $ (18,685 ) $ 2,243,845 December 31, 2016 Amortized Gross Gross Fair Value ($ in Thousands) Investment securities available for sale U. S. Treasury securities $ 1,000 $ — $ — $ 1,000 Residential mortgage-related securities FNMA / FHLMC 625,234 17,298 (2,602 ) 639,930 GNMA 2,028,301 1,372 (25,198 ) 2,004,475 Private-label 1,134 1 (14 ) 1,121 GNMA commercial mortgage-related securities 2,064,508 356 (35,966 ) 2,028,898 Other securities (debt and equity) 4,718 105 (21 ) 4,802 Total investment securities available for sale $ 4,724,895 $ 19,132 $ (63,801 ) $ 4,680,226 Investment securities held to maturity Obligations of state and political subdivisions (municipal securities) $ 1,145,843 $ 3,868 $ (12,036 ) $ 1,137,675 Residential mortgage-related securities FNMA / FHLMC 37,697 439 (693 ) 37,443 GNMA 89,996 216 (656 ) 89,556 Total investment securities held to maturity $ 1,273,536 $ 4,523 $ (13,385 ) $ 1,264,674
Investment securities held to maturity	The amortized cost and fair values of securities available for sale and held to maturity were as follows. September 30, 2017 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value ($ in Thousands) Investment securities available for sale U. S. Treasury securities $ 1,003 $ — $ (2 ) $ 1,001 Residential mortgage-related securities FNMA / FHLMC 494,041 12,780 (1,560 ) 505,261 GNMA 1,681,380 2,504 (16,048 ) 1,667,836 Private-label 1,083 — (11 ) 1,072 GNMA commercial mortgage-related securities 1,539,169 73 (26,165 ) 1,513,077 Asset backed securities 108,590 63 (25 ) 108,628 Other securities (debt and equity) 4,718 132 (26 ) 4,824 Total investment securities available for sale $ 3,829,984 $ 15,552 $ (43,837 ) $ 3,801,699 Investment securities held to maturity Obligations of state and political subdivisions (municipal securities) $ 1,192,290 $ 14,525 $ (3,858 ) $ 1,202,957 Residential mortgage-related securities FNMA / FHLMC 42,386 464 (404 ) 42,446 GNMA 444,196 3,712 (2,615 ) 445,293 GNMA commercial mortgage-related securities 554,707 10,250 (11,808 ) 553,149 Total investment securities held to maturity $ 2,233,579 $ 28,951 $ (18,685 ) $ 2,243,845 December 31, 2016 Amortized Gross Gross Fair Value ($ in Thousands) Investment securities available for sale U. S. Treasury securities $ 1,000 $ — $ — $ 1,000 Residential mortgage-related securities FNMA / FHLMC 625,234 17,298 (2,602 ) 639,930 GNMA 2,028,301 1,372 (25,198 ) 2,004,475 Private-label 1,134 1 (14 ) 1,121 GNMA commercial mortgage-related securities 2,064,508 356 (35,966 ) 2,028,898 Other securities (debt and equity) 4,718 105 (21 ) 4,802 Total investment securities available for sale $ 4,724,895 $ 19,132 $ (63,801 ) $ 4,680,226 Investment securities held to maturity Obligations of state and political subdivisions (municipal securities) $ 1,145,843 $ 3,868 $ (12,036 ) $ 1,137,675 Residential mortgage-related securities FNMA / FHLMC 37,697 439 (693 ) 37,443 GNMA 89,996 216 (656 ) 89,556 Total investment securities held to maturity $ 1,273,536 $ 4,523 $ (13,385 ) $ 1,264,674
Amortized cost and fair values of investment securities by contractual maturity	The amortized cost and fair values of investment securities available for sale and held to maturity at September 30, 2017 , are shown below. Expected maturities will differ from contractual maturities because borrowers may have the right to call or prepay obligations with or without call or prepayment penalties. Available for Sale Held to Maturity Amortized Cost Fair Value Amortized Cost Fair Value ($ in Thousands) Due in one year or less $ 1,000 $ 1,000 $ 54,259 $ 48,123 Due after one year through five years 4,703 4,675 222,037 227,978 Due after five years through ten years — — 281,559 284,789 Due after ten years — — 634,435 642,067 Total debt securities 5,703 5,675 1,192,290 1,202,957 Residential mortgage-related securities FNMA / FHLMC 494,041 505,261 42,386 42,446 GNMA 1,681,380 1,667,836 444,196 445,293 Private-label 1,083 1,072 — — GNMA commercial mortgage-related securities 1,539,169 1,513,077 554,707 553,149 Asset backed securities 108,590 108,628 — — Equity securities 18 150 — — Total investment securities $ 3,829,984 $ 3,801,699 $ 2,233,579 $ 2,243,845 Ratio of Fair Value to Amortized Cost 99.3 % 100.5 %
Realized gains and losses and proceeds from sale	The proceeds from the sale of investment securities for the first nine months ended September 30, 2017 and 2016 are shown below. Nine Months Ended September 30, 2017 2016 ($ in Thousands) Gross gains on available for sale securities $ — $ 6,403 Gross gains on held to maturity securities 364 — Total gains 364 6,403 Gross losses on available for sale securities — (202 ) Gross losses on held to maturity securities (5 ) — Total losses (5 ) (202 ) Investment securities gains, net $ 359 $ 6,201 Proceeds from sales of investment securities $ 16,059 $ 359,591
Unrealized losses and fair value of available for sale and held to maturity securities, by investment category and time length	The following represents gross unrealized losses and the related fair value of investment securities available for sale and held to maturity, aggregated by investment category and length of time individual securities have been in a continuous unrealized loss position, at September 30, 2017 . Less than 12 months 12 months or more Total September 30, 2017 Number of Securities Unrealized Losses Fair Value Number of Securities Unrealized Losses Fair Value Unrealized Losses Fair Value ($ in Thousands) Investment securities available for sale U.S. Treasury securities 1 $ (2 ) $ 1,001 — $ — $ — $ (2 ) $ 1,001 Residential mortgage-related securities FNMA / FHLMC 16 (1,254 ) 177,782 2 (306 ) 33,842 (1,560 ) 211,624 GNMA 22 (9,455 ) 687,814 14 (6,593 ) 378,457 (16,048 ) 1,066,271 Private-label — — — 1 (11 ) 1,072 (11 ) 1,072 GNMA commercial mortgage-related securities 42 (4,962 ) 551,833 56 (21,203 ) 891,178 (26,165 ) 1,443,011 Asset backed securities 5 (25 ) 52,851 — — — (25 ) 52,851 Other securities (debt and equity) 1 (26 ) 174 — — — (26 ) 174 Total 87 $ (15,724 ) $ 1,471,455 73 $ (28,113 ) $ 1,304,549 $ (43,837 ) $ 2,776,004 Investment securities held to maturity Obligations of state and political subdivisions (municipal securities) 195 $ (1,195 ) $ 138,178 108 $ (2,663 ) $ 94,432 $ (3,858 ) $ 232,610 Residential mortgage-related securities FNMA / FHLMC 12 (124 ) 17,816 4 (280 ) 9,910 (404 ) 27,726 GNMA 29 (1,628 ) 223,379 7 (987 ) 67,981 (2,615 ) 291,360 GNMA commercial mortgage-related securities 5 (841 ) 94,758 19 (10,967 ) 427,161 (11,808 ) 521,919 Total 241 $ (3,788 ) $ 474,131 138 $ (14,897 ) $ 599,484 $ (18,685 ) $ 1,073,615 For comparative purposes, the following represents gross unrealized losses and the related fair value of investment securities available for sale and held to maturity, aggregated by investment category and length of time that individual securities have been in a continuous unrealized loss position, at December 31, 2016 . Less than 12 months 12 months or more Total December 31, 2016 Number Unrealized Fair Number Unrealized Fair Unrealized Fair ($ in Thousands) Investment securities available for sale Residential mortgage-related securities FNMA / FHLMC 14 $ (2,602 ) $ 244,252 — $ — $ — $ (2,602 ) $ 244,252 GNMA 54 (25,198 ) 1,723,523 — — — (25,198 ) 1,723,523 Private-label — — — 1 (14 ) 1,119 (14 ) 1,119 GNMA commercial mortgage-related securities 74 (16,445 ) 1,427,889 21 (19,521 ) 429,258 (35,966 ) 1,857,147 Other securities (debt and equity) 3 (21 ) 1,479 — — — (21 ) 1,479 Total 145 $ (44,266 ) $ 3,397,143 22 $ (19,535 ) $ 430,377 $ (63,801 ) $ 3,827,520 Investment securities held to maturity Obligations of state and political subdivisions (municipal securities) 700 $ (11,937 ) $ 414,186 4 $ (99 ) $ 1,752 $ (12,036 ) $ 415,938 Residential mortgage-related securities FNMA / FHLMC 14 (441 ) 17,477 1 (252 ) 6,031 (693 ) 23,508 GNMA 39 (656 ) 64,633 — — — (656 ) 64,633 Total 753 $ (13,034 ) $ 496,296 5 $ (351 ) $ 7,783 $ (13,385 ) $ 504,079

Loans (Tables)

Loans (Tables)	9 Months Ended
	Sep. 30, 2017
Receivables [Abstract]
Loan composition	The period end loan composition was as follows. September 30, December 31, ($ in Thousands) Commercial and industrial $ 6,534,660 $ 6,489,014 Commercial real estate — owner occupied 827,064 897,724 Commercial and business lending 7,361,724 7,386,738 Commercial real estate — investor 3,345,536 3,574,732 Real estate construction 1,552,135 1,432,497 Commercial real estate lending 4,897,671 5,007,229 Total commercial 12,259,395 12,393,967 Residential mortgage 7,408,471 6,332,327 Home equity 890,130 934,443 Other consumer 373,464 393,979 Total consumer 8,672,065 7,660,749 Total loans $ 20,931,460 $ 20,054,716
Commercial and consumer loans by credit quality indicator	The following table presents commercial and consumer loans by credit quality indicator at September 30, 2017 . Pass Special Mention Potential Problem Nonaccrual Total ($ in Thousands) Commercial and industrial $ 6,101,491 $ 157,106 $ 153,779 $ 122,284 $ 6,534,660 Commercial real estate - owner occupied 742,257 11,741 57,468 15,598 827,064 Commercial and business lending 6,843,748 168,847 211,247 137,882 7,361,724 Commercial real estate - investor 3,284,497 10,726 46,770 3,543 3,345,536 Real estate construction 1,550,462 15 118 1,540 1,552,135 Commercial real estate lending 4,834,959 10,741 46,888 5,083 4,897,671 Total commercial 11,678,707 179,588 258,135 142,965 12,259,395 Residential mortgage 7,352,286 881 650 54,654 7,408,471 Home equity 876,003 1,364 124 12,639 890,130 Other consumer 372,638 567 — 259 373,464 Total consumer 8,600,927 2,812 774 67,552 8,672,065 Total $ 20,279,634 $ 182,400 $ 258,909 $ 210,517 $ 20,931,460 The following table presents commercial and consumer loans by credit quality indicator at December 31, 2016 . Pass Special Mention Potential Problem Nonaccrual Total ($ in Thousands) Commercial and industrial $ 5,937,119 $ 141,328 $ 227,196 $ 183,371 $ 6,489,014 Commercial real estate - owner occupied 805,871 17,785 64,524 9,544 897,724 Commercial and business lending 6,742,990 159,113 291,720 192,915 7,386,738 Commercial real estate - investor 3,491,217 14,236 51,228 18,051 3,574,732 Real estate construction 1,429,083 105 2,465 844 1,432,497 Commercial real estate lending 4,920,300 14,341 53,693 18,895 5,007,229 Total commercial 11,663,290 173,454 345,413 211,810 12,393,967 Residential mortgage 6,275,162 1,314 5,615 50,236 6,332,327 Home equity 919,740 1,588 114 13,001 934,443 Other consumer 393,161 562 — 256 393,979 Total consumer 7,588,063 3,464 5,729 63,493 7,660,749 Total $ 19,251,353 $ 176,918 $ 351,142 $ 275,303 $ 20,054,716
Summarized details of Loans	The following table presents loans by past due status at September 30, 2017 . Current 30-59 Days Past Due 60-89 Days Past Due 90 Days or More Past Due (a) Nonaccrual (b) Total ($ in Thousands) Commercial and industrial $ 6,410,690 $ 1,254 $ 124 $ 308 $ 122,284 $ 6,534,660 Commercial real estate - owner occupied 809,944 1,522 — — 15,598 827,064 Commercial and business lending 7,220,634 2,776 124 308 137,882 7,361,724 Commercial real estate - investor 3,340,884 1,109 — — 3,543 3,345,536 Real estate construction 1,549,895 685 15 — 1,540 1,552,135 Commercial real estate lending 4,890,779 1,794 15 — 5,083 4,897,671 Total commercial 12,111,413 4,570 139 308 142,965 12,259,395 Residential mortgage 7,344,947 8,327 543 — 54,654 7,408,471 Home equity 870,300 5,852 1,339 — 12,639 890,130 Other consumer 370,216 987 699 1,303 259 373,464 Total consumer 8,585,463 15,166 2,581 1,303 67,552 8,672,065 Total $ 20,696,876 $ 19,736 $ 2,720 $ 1,611 $ 210,517 $ 20,931,460 (a) The recorded investment in loans past due 90 days or more and still accruing totaled $2 million at September 30, 2017 (the same as the reported balances for the accruing loans noted above). (b) Of the total nonaccrual loans, $156 million or 74% were current with respect to payment at September 30, 2017 . The following table presents loans by past due status at December 31, 2016 . Current 30-59 Days Past Due 60-89 Days Past Due 90 Days or More Past Due (a) Nonaccrual (b) Total ($ in Thousands) Commercial and industrial $ 6,303,994 $ 965 $ 448 $ 236 $ 183,371 $ 6,489,014 Commercial real estate - owner occupied 886,796 968 416 — 9,544 897,724 Commercial and business lending 7,190,790 1,933 864 236 192,915 7,386,738 Commercial real estate - investor 3,555,750 431 500 — 18,051 3,574,732 Real estate construction 1,431,284 264 105 — 844 1,432,497 Commercial real estate lending 4,987,034 695 605 — 18,895 5,007,229 Total commercial 12,177,824 2,628 1,469 236 211,810 12,393,967 Residential mortgage 6,273,949 7,298 844 — 50,236 6,332,327 Home equity 915,593 4,265 1,584 — 13,001 934,443 Other consumer 389,157 2,471 718 1,377 256 393,979 Total consumer 7,578,699 14,034 3,146 1,377 63,493 7,660,749 Total $ 19,756,523 $ 16,662 $ 4,615 $ 1,613 $ 275,303 $ 20,054,716 (a) The recorded investment in loans past due 90 days or more and still accruing totaled $2 million at December 31, 2016 (the same as the reported balances for the accruing loans noted above). (b) Of the total nonaccrual loans, $224 million or 81% were current with respect to payment at December 31, 2016
Summarized details of impaired Loans	The following table presents impaired loans individually evaluated under ASC Topic 310 at September 30, 2017 . Recorded Unpaid Related Average Interest ($ in Thousands) Loans with a related allowance Commercial and industrial $ 67,226 $ 72,343 $ 11,540 $ 76,082 $ 1,050 Commercial real estate — owner occupied 12,255 12,374 1,549 12,032 192 Commercial and business lending 79,481 84,717 13,089 88,114 1,242 Commercial real estate — investor 16,974 16,988 1,812 16,992 1,224 Real estate construction 476 586 75 489 22 Commercial real estate lending 17,450 17,574 1,887 17,481 1,246 Total commercial 96,931 102,291 14,976 105,595 2,488 Residential mortgage 42,684 45,028 6,893 43,090 1,258 Home equity 10,351 11,283 3,684 10,537 411 Other consumer 1,092 1,093 118 1,095 1 Total consumer 54,127 57,404 10,695 54,722 1,670 Total loans (a) $ 151,058 $ 159,695 $ 25,671 $ 160,317 $ 4,158 Loans with no related allowance Commercial and industrial $ 86,802 $ 99,480 $ — $ 100,398 $ 927 Commercial real estate — owner occupied 6,871 7,716 — 7,016 — Commercial and business lending 93,673 107,196 — 107,414 927 Commercial real estate — investor 589 732 — 606 — Real estate construction 213 218 — 220 — Commercial real estate lending 802 950 — 826 — Total commercial 94,475 108,146 — 108,240 927 Residential mortgage 6,469 7,074 — 6,492 105 Home equity 540 543 — 540 — Other consumer — — — — — Total consumer 7,009 7,617 — 7,032 105 Total loans (a) $ 101,484 $ 115,763 $ — $ 115,272 $ 1,032 Total Commercial and industrial $ 154,028 $ 171,823 $ 11,540 $ 176,480 $ 1,977 Commercial real estate — owner occupied 19,126 20,090 1,549 19,048 192 Commercial and business lending 173,154 191,913 13,089 195,528 2,169 Commercial real estate — investor 17,563 17,720 1,812 17,598 1,224 Real estate construction 689 804 75 709 22 Commercial real estate lending 18,252 18,524 1,887 18,307 1,246 Total commercial 191,406 210,437 14,976 213,835 3,415 Residential mortgage 49,153 52,102 6,893 49,582 1,363 Home equity 10,891 11,826 3,684 11,077 411 Other consumer 1,092 1,093 118 1,095 1 Total consumer 61,136 65,021 10,695 61,754 1,775 Total loans (a) $ 252,542 $ 275,458 $ 25,671 $ 275,589 $ 5,190 (a) The net recorded investment (defined as recorded investment, net of the related allowance) of the impaired loans represented 82% of the unpaid principal balance at September 30, 2017 . The following table presents impaired loans individually evaluated under ASC Topic 310 at December 31, 2016 . Recorded Investment Unpaid Principal Balance Related Allowance Average Recorded Investment Interest Income Recognized ($ in Thousands) Loans with a related allowance Commercial and industrial $ 99,786 $ 105,175 $ 21,047 $ 104,808 $ 2,345 Commercial real estate — owner occupied 5,544 5,568 23 5,840 263 Commercial and business lending 105,330 110,743 21,070 110,648 2,608 Commercial real estate — investor 26,764 27,031 3,410 30,665 2,120 Real estate construction 509 648 84 529 31 Commercial real estate lending 27,273 27,679 3,494 31,194 2,151 Total commercial 132,603 138,422 24,564 141,842 4,759 Residential mortgage 37,902 39,979 6,438 38,608 1,551 Home equity 11,070 11,909 3,943 11,420 627 Other consumer 1,012 1,023 109 1,021 2 Total consumer 49,984 52,911 10,490 51,049 2,180 Total loans (a) $ 182,587 $ 191,333 $ 35,054 $ 192,891 $ 6,939 Loans with no related allowance Commercial and industrial $ 113,485 $ 134,863 $ — $ 117,980 $ 1,519 Commercial real estate — owner occupied 8,439 9,266 — 8,759 138 Commercial and business lending 121,924 144,129 — 126,739 1,657 Commercial real estate — investor 6,144 6,478 — 7,092 — Real estate construction — — — — — Commercial real estate lending 6,144 6,478 — 7,092 — Total commercial 128,068 150,607 — 133,831 1,657 Residential mortgage 5,974 6,998 — 6,610 184 Home equity 106 107 — 107 4 Other consumer — — — — — Total consumer 6,080 7,105 — 6,717 188 Total loans (a) $ 134,148 $ 157,712 $ — $ 140,548 $ 1,845 Total Commercial and industrial $ 213,271 $ 240,038 $ 21,047 $ 222,788 $ 3,864 Commercial real estate — owner occupied 13,983 14,834 23 14,599 401 Commercial and business lending 227,254 254,872 21,070 237,387 4,265 Commercial real estate — investor 32,908 33,509 3,410 37,757 2,120 Real estate construction 509 648 84 529 31 Commercial real estate lending 33,417 34,157 3,494 38,286 2,151 Total commercial 260,671 289,029 24,564 275,673 6,416 Residential mortgage 43,876 46,977 6,438 45,218 1,735 Home equity 11,176 12,016 3,943 11,527 631 Other consumer 1,012 1,023 109 1,021 2 Total consumer 56,064 60,016 10,490 57,766 2,368 Total loans (a) $ 316,735 $ 349,045 $ 35,054 $ 333,439 $ 8,784 (a) The net recorded investment (defined as recorded investment, net of the related allowance) of the impaired loans represented 81% of the unpaid principal balance at December 31, 2016
Nonaccrual and performing restructured loans	The following table presents nonaccrual and performing restructured loans by loan portfolio. September 30, 2017 December 31, 2016 Performing Restructured Loans Nonaccrual Restructured Loans (a) Performing Restructured Loans Nonaccrual Restructured Loans (a) ($ in Thousands) Commercial and industrial $ 32,572 $ 7,994 $ 31,884 $ 1,276 Commercial real estate — owner occupied 4,077 2,145 5,490 2,220 Commercial real estate — investor 14,294 589 15,289 924 Real estate construction 316 160 359 150 Residential mortgage 16,859 20,248 18,100 21,906 Home equity 7,987 2,364 7,756 2,877 Other consumer 1,073 20 979 32 Total $ 77,178 $ 33,520 $ 79,857 $ 29,385 (a)
Summary of restructured loans	The following table provides the number of loans modified in a troubled debt restructuring by loan portfolio during the nine months ended September 30, 2017 and 2016 , respectively, and the recorded investment and unpaid principal balance as of September 30, 2017 and 2016 , respectively. Nine Months Ended September 30, 2017 Nine Months Ended September 30, 2016 Number of Loans Recorded Investment (a) Unpaid Principal Balance (b) Number of Loans Recorded Investment (a) Unpaid Principal Balance (b) ($ in Thousands) Commercial and industrial 19 $ 11,387 $ 15,898 10 $ 2,455 $ 2,517 Commercial real estate — owner occupied 2 710 710 1 117 124 Real estate construction — — — 1 66 91 Residential mortgage 48 4,445 4,638 56 4,676 4,922 Home equity 35 934 1,182 47 1,709 1,793 Other consumer — — — 1 15 16 Total 104 $ 17,476 $ 22,428 116 $ 9,038 $ 9,463 (a) Represents post-modification outstanding recorded investment. (b)
Troubled debt restructurings subsequent redefault	The following table provides the number of loans modified in a troubled debt restructuring during the previous twelve months which subsequently defaulted during the nine months ended September 30, 2017 and 2016 , respectively, as well as the recorded investment in these restructured loans as of September 30, 2017 and 2016 , respectively. Nine Months Ended September 30, 2017 Nine Months Ended September 30, 2016 Number of Loans Recorded Investment Number of Loans Recorded Investment ($ in Thousands) Commercial and industrial 1 $ 1 — $ — Residential mortgage 21 1,335 36 3,310 Home equity 14 371 12 182 Other consumer — — 1 15 Total 36 $ 1,707 49 $ 3,507
Changes in the allowance for loan losses by portfolio segment	($ in Millions) Nine Months Ended September 30, 2017 Year Ended December 31, 2016 Balance at beginning of period $ 38 $ 42 Charge offs (26 ) (59 ) Recoveries — — Net Charge offs (26 ) (59 ) Provision for loan losses 18 55 Balance at end of period $ 30 $ 38 Allowance for loan losses Individually evaluated for impairment $ 2 $ 14 Collectively evaluated for impairment 28 24 Total allowance for loan losses $ 30 $ 38 Loans Individually evaluated for impairment $ 92 $ 147 Collectively evaluated for impairment 485 521 Total loans $ 577 $ 668 nine months ended September 30, 2017 . ($ in Thousands) Commercial and Commercial real estate Commercial real estate - Real estate Residential Home Other Total December 31, 2016 $ 140,126 $ 14,034 $ 45,285 $ 26,932 $ 27,046 $ 20,364 $ 4,548 $ 278,335 Charge offs (33,928 ) (83 ) (803 ) (225 ) (1,472 ) (2,208 ) (3,238 ) (41,957 ) Recoveries 9,072 158 218 60 754 2,348 563 13,173 Net Charge offs (24,856 ) 75 (585 ) (165 ) (718 ) 140 (2,675 ) (28,784 ) Provision for loan losses 23,587 (4,352 ) 1,798 (1,340 ) 4,632 (479 ) 3,154 27,000 September 30, 2017 $ 138,857 $ 9,757 $ 46,498 $ 25,427 $ 30,960 $ 20,025 $ 5,027 $ 276,551 Allowance for loan losses Individually evaluated for impairment $ 11,540 $ 1,549 $ 1,812 $ 75 $ 6,893 $ 3,684 $ 118 $ 25,671 Collectively evaluated for impairment 127,317 8,208 44,686 25,352 24,067 16,341 4,909 250,880 Total allowance for loan losses $ 138,857 $ 9,757 $ 46,498 $ 25,427 $ 30,960 $ 20,025 $ 5,027 $ 276,551 Loans Individually evaluated for impairment $ 154,028 $ 19,126 $ 17,563 $ 689 $ 49,153 $ 10,891 $ 1,092 $ 252,542 Collectively evaluated for impairment 6,380,632 807,938 3,327,973 1,551,446 7,359,318 879,239 372,372 20,678,918 Total loans $ 6,534,660 $ 827,064 $ 3,345,536 $ 1,552,135 $ 7,408,471 $ 890,130 $ 373,464 $ 20,931,460 For comparison purposes, a summary of the changes in the allowance for loan losses by portfolio segment for the year ended December 31, 2016 , was as follows. ($ in Thousands) Commercial and Commercial real estate Commercial real estate - Real estate Residential Home Other Total December 31, 2015 $ 129,959 $ 18,680 $ 43,018 $ 25,266 $ 28,261 $ 23,555 $ 5,525 $ 274,264 Charge offs (71,016 ) (512 ) (1,504 ) (558 ) (4,332 ) (4,686 ) (3,831 ) (86,439 ) Recoveries 14,543 74 1,624 203 755 3,491 820 21,510 Net Charge offs (56,473 ) (438 ) 120 (355 ) (3,577 ) (1,195 ) (3,011 ) (64,929 ) Provision for loan losses 66,640 (4,208 ) 2,147 2,021 2,362 (1,996 ) 2,034 69,000 December 31, 2016 $ 140,126 $ 14,034 $ 45,285 $ 26,932 $ 27,046 $ 20,364 $ 4,548 $ 278,335 Allowance for loan losses Individually evaluated for impairment $ 21,047 $ 23 $ 3,410 $ 84 $ 6,438 $ 3,943 $ 109 $ 35,054 Collectively evaluated for impairment 119,079 14,011 41,875 26,848 20,608 16,421 4,439 243,281 Total allowance for loan losses $ 140,126 $ 14,034 $ 45,285 $ 26,932 $ 27,046 $ 20,364 $ 4,548 $ 278,335 Loans Individually evaluated for impairment $ 213,271 $ 13,983 $ 32,908 $ 509 $ 43,876 $ 11,176 $ 1,012 $ 316,735 Collectively evaluated for impairment 6,275,743 883,741 3,541,824 1,431,988 6,288,451 923,267 392,967 19,737,981 Total loans $ 6,489,014 $ 897,724 $ 3,574,732 $ 1,432,497 $ 6,332,327 $ 934,443 $ 393,979 $ 20,054,716
Changes in the allowance for loan losses by oil and gas segment	($ in Millions) Nine Months Ended September 30, 2017 Year Ended December 31, 2016 Balance at beginning of period $ 38 $ 42 Charge offs (26 ) (59 ) Recoveries — — Net Charge offs (26 ) (59 ) Provision for loan losses 18 55 Balance at end of period $ 30 $ 38 Allowance for loan losses Individually evaluated for impairment $ 2 $ 14 Collectively evaluated for impairment 28 24 Total allowance for loan losses $ 30 $ 38 Loans Individually evaluated for impairment $ 92 $ 147 Collectively evaluated for impairment 485 521 Total loans $ 577 $ 668 nine months ended September 30, 2017 . ($ in Thousands) Commercial and Commercial real estate Commercial real estate - Real estate Residential Home Other Total December 31, 2016 $ 140,126 $ 14,034 $ 45,285 $ 26,932 $ 27,046 $ 20,364 $ 4,548 $ 278,335 Charge offs (33,928 ) (83 ) (803 ) (225 ) (1,472 ) (2,208 ) (3,238 ) (41,957 ) Recoveries 9,072 158 218 60 754 2,348 563 13,173 Net Charge offs (24,856 ) 75 (585 ) (165 ) (718 ) 140 (2,675 ) (28,784 ) Provision for loan losses 23,587 (4,352 ) 1,798 (1,340 ) 4,632 (479 ) 3,154 27,000 September 30, 2017 $ 138,857 $ 9,757 $ 46,498 $ 25,427 $ 30,960 $ 20,025 $ 5,027 $ 276,551 Allowance for loan losses Individually evaluated for impairment $ 11,540 $ 1,549 $ 1,812 $ 75 $ 6,893 $ 3,684 $ 118 $ 25,671 Collectively evaluated for impairment 127,317 8,208 44,686 25,352 24,067 16,341 4,909 250,880 Total allowance for loan losses $ 138,857 $ 9,757 $ 46,498 $ 25,427 $ 30,960 $ 20,025 $ 5,027 $ 276,551 Loans Individually evaluated for impairment $ 154,028 $ 19,126 $ 17,563 $ 689 $ 49,153 $ 10,891 $ 1,092 $ 252,542 Collectively evaluated for impairment 6,380,632 807,938 3,327,973 1,551,446 7,359,318 879,239 372,372 20,678,918 Total loans $ 6,534,660 $ 827,064 $ 3,345,536 $ 1,552,135 $ 7,408,471 $ 890,130 $ 373,464 $ 20,931,460 For comparison purposes, a summary of the changes in the allowance for loan losses by portfolio segment for the year ended December 31, 2016 , was as follows. ($ in Thousands) Commercial and Commercial real estate Commercial real estate - Real estate Residential Home Other Total December 31, 2015 $ 129,959 $ 18,680 $ 43,018 $ 25,266 $ 28,261 $ 23,555 $ 5,525 $ 274,264 Charge offs (71,016 ) (512 ) (1,504 ) (558 ) (4,332 ) (4,686 ) (3,831 ) (86,439 ) Recoveries 14,543 74 1,624 203 755 3,491 820 21,510 Net Charge offs (56,473 ) (438 ) 120 (355 ) (3,577 ) (1,195 ) (3,011 ) (64,929 ) Provision for loan losses 66,640 (4,208 ) 2,147 2,021 2,362 (1,996 ) 2,034 69,000 December 31, 2016 $ 140,126 $ 14,034 $ 45,285 $ 26,932 $ 27,046 $ 20,364 $ 4,548 $ 278,335 Allowance for loan losses Individually evaluated for impairment $ 21,047 $ 23 $ 3,410 $ 84 $ 6,438 $ 3,943 $ 109 $ 35,054 Collectively evaluated for impairment 119,079 14,011 41,875 26,848 20,608 16,421 4,439 243,281 Total allowance for loan losses $ 140,126 $ 14,034 $ 45,285 $ 26,932 $ 27,046 $ 20,364 $ 4,548 $ 278,335 Loans Individually evaluated for impairment $ 213,271 $ 13,983 $ 32,908 $ 509 $ 43,876 $ 11,176 $ 1,012 $ 316,735 Collectively evaluated for impairment 6,275,743 883,741 3,541,824 1,431,988 6,288,451 923,267 392,967 19,737,981 Total loans $ 6,489,014 $ 897,724 $ 3,574,732 $ 1,432,497 $ 6,332,327 $ 934,443 $ 393,979 $ 20,054,716
Changes in the allowance for unfunded commitments	The following table presents a summary of the changes in the allowance for unfunded commitments. Nine Months Ended September 30, 2017 Year Ended December 31, 2016 ($ in Thousands) Allowance for Unfunded Commitments Balance at beginning of period $ 25,400 $ 24,400 Provision for unfunded commitments (1,000 ) 1,000 Balance at end of period $ 24,400 $ 25,400

Goodwill and Other Intangible30

Goodwill and Other Intangible Assets (Tables)	9 Months Ended
	Sep. 30, 2017
Goodwill and Intangible Assets Disclosure [Abstract]
Summary of core deposit intangibles and other intangibles	For core deposit intangibles and other intangibles, changes in the gross carrying amount, accumulated amortization, and net book value were as follows. Nine Months Ended September 30, 2017 Year Ended December 31, 2016 ($ in Thousands) Core deposit intangibles Gross carrying amount $ 4,385 $ 4,385 Accumulated amortization (4,385 ) (4,273 ) Net book value $ — $ 112 Amortization during the year $ 112 $ 281 Other intangibles Gross carrying amount $ 32,572 $ 32,410 Accumulated amortization (18,492 ) (17,145 ) Net book value $ 14,080 $ 15,265 Additions during the period $ 162 $ 1,012 Amortization during the year $ 1,347 $ 1,812
Summary of changes in balance of mortgage servicing rights asset and mortgage servicing rights valuation allowance	A summary of changes in the balance of the mortgage servicing rights asset and the mortgage servicing rights valuation allowance was as follows. Nine Months Ended September 30, 2017 Year Ended December 31, 2016 ($ in Thousands) Mortgage servicing rights Mortgage servicing rights at beginning of period $ 62,085 $ 62,150 Additions 4,822 12,262 Amortization (7,635 ) (12,327 ) Mortgage servicing rights at end of period $ 59,272 $ 62,085 Valuation allowance at beginning of period (609 ) (809 ) (Additions) recoveries, net (286 ) 200 Valuation allowance at end of period (895 ) (609 ) Mortgage servicing rights, net $ 58,377 $ 61,476 Fair value of mortgage servicing rights $ 62,625 $ 73,149 Portfolio of residential mortgage loans serviced for others (“servicing portfolio”) $ 7,653,458 $ 7,974,742 Mortgage servicing rights, net to servicing portfolio 0.76 % 0.77 % Mortgage servicing rights expense (a) $ 7,921 $ 12,127 (a)
Summary of estimated future amortization expense	The following table shows the estimated future amortization expense for amortizing intangible assets. The projections of amortization expense are based on existing asset balances, the current interest rate environment, and prepayment speeds as of September 30, 2017 . The actual amortization expense the Corporation recognizes in any given period may be significantly different depending upon acquisition or sale activities, changes in interest rates, prepayment speeds, market conditions, regulatory requirements, and events or circumstances that indicate the carrying amount of an asset may not be recoverable. Estimated Amortization Expense Other Intangibles Mortgage Servicing Rights ($ in Thousands) Three Months Ended December 31, 2017 $ 451 $ 2,593 2018 1,771 9,337 2019 1,472 7,792 2020 1,355 6,522 2021 1,331 5,484 2022 1,308 4,641 Beyond 2022 6,392 22,903 Total Estimated Amortization Expense $ 14,080 $ 59,272

Short and Long-Term Funding (Ta

Short and Long-Term Funding (Tables)	9 Months Ended
	Sep. 30, 2017
Debt Disclosure [Abstract]
Breakdown of short & long-term debt balances	he components of short-term funding (funding with original contractual maturities of one year or less) and long-term funding (funding with original contractual maturities greater than one year). September 30, 2017 December 31, 2016 ($ in Thousands) Short-Term Funding Federal funds purchased $ 220,575 $ 208,150 Securities sold under agreements to repurchase 255,975 300,197 Federal funds purchased and securities sold under agreements to repurchase $ 476,550 $ 508,347 FHLB advances 520,000 482,000 Commercial paper 68,067 101,688 Other short-term funding 588,067 583,688 Total short-term funding $ 1,064,617 $ 1,092,035 Long-Term Funding FHLB advances $ 2,650,172 $ 2,265,188 Senior notes, at par 250,000 250,000 Subordinated notes, at par 250,000 250,000 Other long-term funding and capitalized costs (2,887 ) (3,393 ) Total long-term funding 3,147,285 2,761,795 Total short and long-term funding $ 4,211,902 $ 3,853,830
Remaining contractual maturity of securities sold under agreements to repurchase	The remaining contractual maturity of the securities sold under agreements to repurchase in the consolidated balance sheets as of September 30, 2017 and December 31, 2016 are presented in the following table. Remaining Contractual Maturity of the Agreements Overnight and Continuous Up to 30 days 30-90 days Greater than 90 days Total September 30, 2017 ($ in Thousands) Repurchase agreements Agency mortgage-related securities $ 255,975 $ — $ — $ — $ 255,975 Total $ 255,975 $ — $ — $ — $ 255,975 December 31, 2016 Repurchase agreements Agency mortgage-related securities $ 300,197 $ — $ — $ — $ 300,197 Total $ 300,197 $ — $ — $ — $ 300,197

Derivative and Hedging Activi32

Derivative and Hedging Activities (Tables)	9 Months Ended
	Sep. 30, 2017
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Balance sheet category and fair values of derivative instruments not designated as hedging instruments	The table below identifies the balance sheet category and fair values of the Corporation’s free standing derivative instruments, which are not designated as hedging instruments. September 30, 2017 December 31, 2016 ($ in Thousands) Notional Amount Fair Value Balance Sheet Category Notional Amount Fair Balance Sheet Interest rate-related instruments — customer and mirror $ 2,198,794 $ 26,837 Trading assets $ 2,039,323 $ 33,671 Trading assets Interest rate-related instruments — customer and mirror 2,198,794 (26,469 ) Trading liabilities 2,039,323 (33,188 ) Trading liabilities Foreign currency exchange forwards 130,191 3,053 Trading assets 109,675 2,002 Trading assets Foreign currency exchange forwards 122,307 (3,033 ) Trading liabilities 106,251 (1,943 ) Trading liabilities Commodity contracts 424,996 18,539 Trading assets 127,582 16,725 Trading assets Commodity contracts 396,754 (17,310 ) Trading liabilities 128,368 (15,972 ) Trading liabilities
Summary Of Other derivative instruments not designated as hedging instruments	The table below identifies the balance sheet category and fair values of the Corporation’s derivative instruments, which are not designated as hedging instruments. September 30, 2017 December 31, 2016 ($ in Thousands) Notional Amount Fair Balance Sheet Notional Amount Fair Balance Sheet Interest rate lock commitments (mortgage) $ 354,075 $ 2,729 Other assets $ 285,345 $ 206 Other assets Forward commitments (mortgage) 243,500 234 Other assets 179,600 2,908 Other assets Purchased options (time deposit) 53,074 1,434 Other assets 80,554 2,576 Other assets Written options (time deposit) 53,074 (1,434 ) Other liabilities 80,554 (2,576 ) Other liabilities
Gain (loss) on derivative instruments not designated as hedging instruments	The table below identifies the income statement category of the gains and losses recognized in income on the Corporation’s derivative instruments not designated as hedging instruments. Income Statement Category of Gain / (Loss) Recognized in Income Nine Months Ended September 30, ($ in Thousands) 2017 2016 Derivative Instruments Interest rate-related instruments — customer and mirror, net Capital market fees, net $ (115 ) $ (888 ) Interest rate lock commitments (mortgage) Mortgage banking, net 2,523 2,768 Forward commitments (mortgage) Mortgage banking, net (2,674 ) (2,271 ) Foreign currency exchange forwards Capital market fees, net (39 ) (85 ) Commodity contracts Capital market fees, net 476 690

Balance Sheet Offsetting (Table

Balance Sheet Offsetting (Tables)	9 Months Ended
	Sep. 30, 2017
Offsetting [Abstract]
Balance Sheet Offsetting of Derivative Assets and Liabilities	The following table presents the assets and liabilities subject to an enforceable master netting arrangement. The interest and commodity agreements we have with our commercial customers are not subject to an enforceable master netting arrangement, and therefore, are excluded from this table. Gross amounts recognized Gross amounts not offset in the balance sheet Gross amounts offset in the balance sheet Net amounts presented in the balance sheet Financial instruments Collateral Net amount ($ in Thousands) September 30, 2017 Derivative assets Interest and commodity agreements $ 23,224 $ — $ 23,224 $ (21,783 ) $ (1,441 ) $ — Derivative liabilities Interest and commodity agreements $ 21,783 $ — $ 21,783 $ (21,783 ) $ — $ — December 31, 2016 Derivative assets Interest and commodity agreements $ 18,031 $ — $ 18,031 $ (18,031 ) $ — $ — Derivative liabilities Interest and commodity agreements $ 31,075 $ — $ 31,075 $ (18,031 ) $ (11,148 ) $ 1,896

Commitments, Off-Balance Shee34

Commitments, Off-Balance Sheet Arrangements, Legal Proceedings and Regulatory Matters (Tables)	9 Months Ended
	Sep. 30, 2017
Commitments and Contingencies Disclosure [Abstract]
Summary of lending-related and other commitments	The following is a summary of lending-related commitments. September 30, 2017 December 31, 2016 ($ in Thousands) Commitments to extend credit, excluding commitments to originate residential mortgage loans held for sale (a)(b) $ 8,002,766 $ 8,131,131 Commercial letters of credit (a) 8,961 7,923 Standby letters of credit (c) 233,783 259,632 (a) These off-balance sheet financial instruments are exercisable at the market rate prevailing at the date the underlying transaction will be completed and, thus, are deemed to have no current fair value, or the fair value is based on fees currently charged to enter into similar agreements and is not material at September 30, 2017 or December 31, 2016 . (b) Interest rate lock commitments to originate residential mortgage loans held for sale are considered derivative instruments and are disclosed in Note 10 . (c) The Corporation has established a liability of $2 million at September 30, 2017 and $3 million at December 31, 2016
Summary of changes in the residential mortgage repurchase reserve	The following summarizes the changes in the mortgage repurchase reserve. Nine Months Ended September 30, 2017 Year Ended December 31, 2016 ($ in Thousands) Balance at beginning of period $ 900 $ 1,197 Repurchase provision expense 165 456 Adjustments to provision expense — (750 ) Charge offs, net (148 ) (3 ) Balance at end of period $ 917 $ 900

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2017
Fair Value Disclosures [Abstract]
Assets and Liabilities Measured on Recurring Basis at Fair Value	The table below presents the Corporation’s financial instruments measured at fair value on a recurring basis as of September 30, 2017 and December 31, 2016 , aggregated by the level in the fair value hierarchy within which those measurements fall. Fair Value Hierarchy September 30, 2017 December 31, 2016 ($ in Thousands) Assets Investment securities available for sale: U.S. Treasury securities Level 1 $ 1,001 $ 1,000 Residential mortgage-related securities: FNMA / FHLMC Level 2 505,261 639,930 GNMA Level 2 1,667,836 2,004,475 Private-label Level 2 1,072 1,121 GNMA commercial mortgage-related securities Level 2 1,513,077 2,028,898 Asset backed securities Level 2 108,628 — Other securities (debt and equity) Level 1 1,650 1,602 Other securities (debt and equity) Level 2 3,174 3,000 Other securities (debt and equity) Level 3 — 200 Total investment securities available for sale Level 1 2,651 2,602 Total investment securities available for sale Level 2 3,799,048 4,677,424 Total investment securities available for sale Level 3 — 200 Residential loans held for sale (a) Level 2 113,064 — Interest rate-related instruments Level 2 26,837 33,671 Foreign currency exchange forwards Level 2 3,053 2,002 Interest rate lock commitments to originate residential mortgage loans held for sale Level 3 2,729 206 Forward commitments to sell residential mortgage loans Level 3 234 2,908 Commodity contracts Level 2 18,539 16,725 Purchased options (time deposit) Level 2 1,434 2,576 Liabilities Interest rate-related instruments Level 2 $ 26,469 $ 33,188 Foreign currency exchange forwards Level 2 3,033 1,943 Commodity contracts Level 2 17,310 15,972 Written options (time deposit) Level 2 1,434 2,576 (a)
Assets and Liabilities Measured at Fair Value Using Significant Unobservable Inputs (Level 3)	The table below presents a rollforward of the balance sheet amounts for the nine months ended September 30, 2017 and the year ended December 31, 2016 , for financial instruments measured on a recurring basis and classified within Level 3 of the fair value hierarchy. Investment Securities Available for Sale Derivative Financial Instruments ($ in Thousands) Balance December 31, 2015 $ 200 $ 1,361 Total net gains included in income Mortgage derivative gain — 1,753 Balance December 31, 2016 $ 200 $ 3,114 Total net losses included in income Mortgage derivative loss — (151 ) Transfer out of level 3 securities (a) (200 ) — Balance September 30, 2017 $ — $ 2,963
Assets and Liabilities Measured on Nonrecurring Basis at Fair Value	The table below presents the Corporation’s assets measured at fair value on a nonrecurring basis, aggregated by the level in the fair value hierarchy within which those measurements fall. Income Statement Category of Adjustment Recognized in Income ($ in Thousands) Fair Value Hierarchy Fair Value September 30, 2017 Assets Commercial loans held for sale (a) Level 2 $ 9,718 Provision for credit losses $ — Impaired loans (c) Level 3 54,762 Provision for credit losses (d) (22,703 ) Other real estate owned Level 2 3,291 Foreclosure / OREO expense, net (939 ) Mortgage servicing rights Level 3 62,625 Mortgage banking, net (286 ) December 31, 2016 Assets Commercial loans held for sale Level 2 $ 12,474 Provision for credit losses $ (559 ) Residential loans held for sale (b) Level 2 108,010 Mortgage banking, net (3,760 ) Impaired loans (c) Level 3 79,270 Provision for credit losses (d) (75,194 ) Other real estate owned Level 2 9,752 Foreclosure / OREO expense, net (1,091 ) Mortgage servicing rights Level 3 73,149 Mortgage banking, net 200 (a) Commercial loans held for sale are carried at the lower of cost or estimated fair value. At September 30, 2017 , the estimated fair value exceeded the cost and therefore there was no adjustment recognized in income. (b) Effective January 1, 2017, residential loans originated for sale are accounted for under the fair value option. Prior periods have not been restated. For more information on this accounting policy change, please refer to Note 3. (c) Represents individually evaluated impaired loans, net of the related allowance for loan losses. (d)
Schedule of Assumptions for Fair Value as of Balance Sheet Date of Assets or Liabilities that relate to Transferor's Continuing Involvement [Table Text Block]	The table below presents information about these inputs and further discussion is found above. Valuation Technique Significant Unobservable Input Weighted Average Input Applied September 30, 2017 Mortgage servicing rights Discounted cash flow Discount rate 11% Mortgage servicing rights Discounted cash flow Constant prepayment rate 12% Impaired Loans Appraisals / Discounted cash flow Collateral / Discount factor 16%
Estimated fair values of financial instruments	Fair value estimates, methods, and assumptions are set forth below for the Corporation’s financial instruments. September 30, 2017 December 31, 2016 Fair Value Hierarchy Level Carrying Amount Fair Value Carrying Amount Fair Value ($ in Thousands) Financial assets Cash and due from banks Level 1 $ 354,331 $ 354,331 $ 446,558 $ 446,558 Interest-bearing deposits in other financial institutions Level 1 109,596 109,596 149,175 149,175 Federal funds sold and securities purchased under agreements to resell Level 1 27,700 27,700 46,500 46,500 Investment securities held to maturity Level 2 2,233,579 2,243,845 1,273,536 1,264,674 Investment securities available for sale Level 1 2,651 2,651 2,602 2,602 Investment securities available for sale Level 2 3,799,048 3,799,048 4,677,424 4,677,424 Investment securities available for sale Level 3 — — 200 200 FHLB and Federal Reserve Bank stocks Level 2 172,446 172,446 140,001 140,001 Commercial loans held for sale Level 2 9,718 9,718 12,474 12,474 Residential loans held for sale Level 2 113,064 113,064 108,010 108,010 Loans, net Level 3 20,654,909 20,504,971 19,776,381 19,680,317 Bank and corporate owned life insurance Level 2 589,093 589,093 585,290 585,290 Derivatives (trading and other assets) Level 2 49,863 49,863 54,974 54,974 Derivatives (trading and other assets) Level 3 2,963 2,963 3,114 3,114 Financial liabilities Noninterest-bearing demand, savings, interest-bearing demand, and money market accounts Level 3 $ 20,012,174 $ 20,012,174 $ 20,282,321 $ 20,282,321 Brokered CDs and other time deposits Level 2 2,321,277 2,321,277 1,606,127 1,606,127 Short-term funding Level 2 1,064,617 1,064,617 1,092,035 1,092,035 Long-term funding Level 2 3,147,285 3,171,059 2,761,795 2,791,841 Standby letters of credit (a) Level 2 2,346 2,346 2,566 2,566 Derivatives (trading and other liabilities) Level 2 48,246 48,246 53,679 53,679 (a) The commitment on standby letters of credit was $234 million and $260 million at September 30, 2017 and December 31, 2016

Retirement Plans (Tables)

Retirement Plans (Tables)	9 Months Ended
	Sep. 30, 2017
Defined Benefit Plan [Abstract]
Net period benefit cost for the pension and postretirement plans	The components of net periodic benefit cost for the RAP and Postretirement Plan for three and nine months ended September 30, 2017 and 2016 were as follows. Three Months Ended September 30, Nine Months Ended September 30, 2017 2016 2017 2016 ($ in Thousands) Components of Net Periodic Benefit Cost RAP Service cost $ 1,713 $ 1,636 $ 5,276 $ 5,086 Interest cost 1,795 1,781 5,307 5,341 Expected return on plan assets (4,929 ) (5,085 ) (14,692 ) (15,215 ) Amortization of prior service cost (19 ) (80 ) (56 ) (55 ) Amortization of actuarial loss 619 621 1,594 1,586 Total net pension cost $ (821 ) $ (1,127 ) $ (2,571 ) $ (3,257 ) Postretirement Plan Interest cost $ 26 $ 35 $ 74 $ 107 Amortization of prior service cost (19 ) — (57 ) — Amortization of actuarial loss 2 — 2 — Total net periodic benefit cost $ 9 $ 35 $ 19 $ 107

Segment Reporting (Tables)

Segment Reporting (Tables)	9 Months Ended
	Sep. 30, 2017
Segment Reporting [Abstract]
Selected segment information	Information about the Corporation’s segments is presented below. Segment Income Statement Data ($ in Thousands) Corporate and Community, Risk Management Consolidated Nine Months Ended September 30, 2017 Net interest income $ 271,615 $ 270,011 $ 12,589 $ 554,215 Noninterest income 36,768 198,546 12,822 248,136 Total revenue 308,383 468,557 25,411 802,351 Credit provision (a) 32,549 15,317 (21,866 ) 26,000 Noninterest expense 116,578 361,580 49,276 527,434 Income (loss) before income taxes 159,256 91,660 (1,999 ) 248,917 Income tax expense (benefit) 53,082 32,081 (15,500 ) 69,663 Net income $ 106,174 $ 59,579 $ 13,501 $ 179,254 Return on average allocated capital (ROCET1) (b) 12.7 % 13.6 % 2.2 % 11.0 % Nine Months Ended September 30, 2016 Net interest income $ 242,800 $ 257,848 $ 26,590 $ 527,238 Noninterest income 35,172 207,460 17,962 260,594 Total revenue 277,972 465,308 44,552 787,832 Credit provision (a) 38,933 18,357 (2,290 ) 55,000 Noninterest expense 109,511 370,714 43,420 523,645 Income (loss) before income taxes 129,528 76,237 3,422 209,187 Income tax expense (benefit) 42,623 26,683 (5,560 ) 63,746 Net income $ 86,905 $ 49,554 $ 8,982 $ 145,441 Return on average allocated capital (ROCET1) (b) 10.9 % 10.5 % 1.4 % 9.7 % Segment Balance Sheet Data ($ in Thousands) Corporate and Community, Risk Management Consolidated Average balances for YTD September 2017 Average earning assets $ 10,846,418 $ 9,418,173 $ 6,587,401 $ 26,851,992 Average loans 10,837,933 9,414,880 248,165 20,500,978 Average deposits 6,759,105 11,568,220 3,486,354 21,813,679 Average allocated capital (CET1) (b) $ 1,121,800 $ 584,774 $ 387,388 $ 2,093,962 Average balances for YTD September 2016 Average earning assets $ 10,097,995 $ 9,287,158 $ 6,508,356 $ 25,893,509 Average loans 10,088,777 9,285,848 166,447 19,541,072 Average deposits 5,906,695 11,320,106 3,531,614 20,758,415 Average allocated capital (CET1) (b) $ 1,063,598 $ 631,484 $ 225,813 $ 1,920,895 (a) The consolidated credit provision is equal to the actual reported provision for credit losses. (b) Segment Income Statement Data ($ in Thousands) Corporate and Commercial Specialty Community, Consumer, and Business Risk Management and Shared Services Consolidated Total Three Months Ended September 30, 2017 Net interest income $ 92,356 $ 90,952 $ 6,814 $ 190,122 Noninterest income 12,278 67,867 5,750 85,895 Total revenue 104,634 158,819 12,564 276,017 Credit provision (a) 9,499 5,046 (9,545 ) 5,000 Noninterest expense 39,681 120,241 17,505 177,427 Income (loss) before income taxes 55,454 33,532 4,604 93,590 Income tax expense (benefit) 19,070 11,736 (2,217 ) 28,589 Net income $ 36,384 $ 21,796 $ 6,821 $ 65,001 Return on average allocated capital (ROCET1) (b) 12.8 % 14.7 % 4.4 % 11.7 % Three Months Ended September 30, 2016 Net interest income $ 83,567 $ 87,274 $ 7,693 $ 178,534 Noninterest income 12,623 78,580 4,031 95,234 Total revenue 96,190 165,854 11,724 273,768 Credit provision (a) 11,080 5,969 3,951 21,000 Noninterest expense 37,968 127,454 9,892 175,314 Income (loss) before income taxes 47,142 32,431 (2,119 ) 77,454 Income tax expense (benefit) 14,907 11,351 (2,620 ) 23,638 Net income $ 32,235 $ 21,080 $ 501 $ 53,816 Return on average allocated capital (ROCET1) (b) 11.7 % 13.2 % (2.9 )% 10.5 % Segment Balance Sheet Data ($ in Thousands) Corporate and Commercial Specialty Community, Consumer, and Business Risk Management and Shared Services Consolidated Total Three Months Ended September 30, 2017 Average earning assets $ 10,923,762 $ 9,608,242 $ 6,927,791 $ 27,459,795 Average loans 10,916,829 9,602,098 380,210 20,899,137 Average deposits 7,398,970 11,788,606 3,253,869 22,441,445 Average allocated capital (CET1) (b) $ 1,125,181 $ 588,841 $ 405,653 $ 2,119,675 Three Months Ended September 30, 2016 Average earning assets $ 10,441,454 $ 9,414,718 $ 6,577,991 $ 26,434,163 Average loans 10,435,341 9,413,401 204,034 20,052,776 Average deposits 6,227,305 11,526,639 3,650,081 21,404,025 Average allocated capital (CET1) (b) $ 1,091,624 $ 633,392 $ 227,600 $ 1,952,616 (a) The consolidated credit provision is equal to the actual reported provision for credit losses. (b)

Accumulated Other Comprehensi38

Accumulated Other Comprehensive Income (Loss) (Tables)	9 Months Ended
	Sep. 30, 2017
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Summary of activity in accumulated other comprehensive income (loss)	The following tables summarize the components, changes, and reclassifications from accumulated other comprehensive income (loss) for the nine months and three months ended September 30, 2017 and 2016, respectively. ($ in Thousands) Investment Securities Available For Sale Defined Benefit Pension and Post Retirement Obligations Accumulated Other Comprehensive Income (Loss) Balance January 1, 2017 $ (20,079 ) $ (34,600 ) $ (54,679 ) Other comprehensive income (loss) before reclassifications 1,646 — 1,646 Amounts reclassified from accumulated other comprehensive income (loss) Personnel expense — 1,483 1,483 Interest income (amortization of net unrealized losses (gains) on available for sale securities transferred to held to maturity securities) (2,499 ) — (2,499 ) Income tax (expense) benefit 328 (567 ) (239 ) Net other comprehensive income (loss) during period (525 ) 916 391 Balance September 30, 2017 $ (20,604 ) $ (33,684 ) $ (54,288 ) Balance January 1, 2016 $ 459 $ (33,075 ) $ (32,616 ) Other comprehensive income (loss) before reclassifications 59,849 — 59,849 Amounts reclassified from accumulated other comprehensive income (loss) Investment securities gain (loss), net (6,201 ) — (6,201 ) Personnel expense — 1,531 1,531 Interest income (amortization of net unrealized losses (gains) on available for sale securities transferred to held to maturity securities) (4,465 ) — (4,465 ) Income tax (expense) benefit (18,768 ) (584 ) (19,352 ) Net other comprehensive income (loss) during period 30,415 947 31,362 Balance September 30, 2016 $ 30,874 $ (32,128 ) $ (1,254 ) Investment Defined Benefit Accumulated Balance July 1, 2017 $ (19,428 ) $ (34,042 ) $ (53,470 ) Other comprehensive income (loss) before reclassifications (1,986 ) — (1,986 ) Amounts reclassified from accumulated other comprehensive income (loss) Personnel expense — 583 583 Interest income (amortization of net unrealized losses (gains) on available for sale securities transferred to held to maturity securities) 76 — 76 Income tax (expense) benefit 734 (225 ) 509 Net other comprehensive income (loss) during period (1,176 ) 358 (818 ) Balance September 30, 2017 $ (20,604 ) $ (33,684 ) $ (54,288 ) Balance July 1, 2016 $ 45,916 $ (32,463 ) $ 13,453 Other comprehensive income (loss) before reclassifications (22,894 ) — (22,894 ) Amounts reclassified from accumulated other comprehensive income (loss) Investment securities gain (loss), net 13 — 13 Personnel expense — 541 541 Interest income (amortization of net unrealized losses (gains) on available for sale securities transferred to held to maturity securities) (1,441 ) — (1,441 ) Income tax (expense) benefit 9,280 (206 ) 9,074 Net other comprehensive income (loss) during period (15,042 ) 335 (14,707 ) Balance September 30, 2016 $ 30,874 $ (32,128 ) $ (1,254 )

Acquisitions (Details Textuals)

Acquisitions (Details Textuals)	Oct. 02, 2017acquisition	Jul. 20, 2017acquisitionshares	Mar. 31, 2017USD ($)acquisition	Mar. 31, 2016USD ($)acquisition
Business Acquisition [Line Items]
Goodwill acquired during period | $			$ 55,000	$ 3,000,000
Additions to finite-lived intangible assets | $			$ 162,000	$ 1,000,000
Number of acquisitions			1	2
Bank Mutual
Business Acquisition [Line Items]
Number of acquisitions		1
Consideration shares transferred | shares		0.422
Subsequent Event | Whitnell
Business Acquisition [Line Items]
Number of acquisitions	1

Summary of Significant Accoun40

Summary of Significant Accounting Policies (Details) $ in Millions	3 Months Ended
	Dec. 31, 2016USD ($)
Reduction in Taxes
Summary of Significant Accounting Policies [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification	$ 1

Earnings Per Common Share (Deta

Earnings Per Common Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Calculations for basic and diluted earnings per common share
Net income	$ 65,001	$ 53,816	$ 179,254	$ 145,441
Preferred stock dividends	(2,339)	(2,188)	(7,008)	(6,555)
Net income available to common equity	62,662	51,628	172,246	138,886
Common shareholder dividends	(18,149)	(16,431)	(54,726)	(49,077)
Unvested share-based payment awards	(105)	(177)	(332)	(565)
Undistributed earnings	44,408	35,020	117,188	89,244
Undistributed earnings allocated to common shareholders	44,150	34,645	116,418	88,294
Undistributed earnings allocated to unvested share-based payment awards	258	375	770	950
Undistributed earnings	44,408	35,020	117,188	89,244
Basic
Distributed earnings to common shareholders	18,149	16,431	54,726	49,077
Undistributed earnings allocated to common shareholders	44,150	34,645	116,418	88,294
Total common shareholders earnings, basic	62,299	51,076	171,144	137,371
Diluted
Distributed earnings to common shareholders	18,149	16,431	54,726	49,077
Undistributed earnings allocated to common shareholders	44,150	34,645	116,418	88,294
Total common shareholders earnings, diluted	$ 62,299	$ 51,076	$ 171,144	$ 137,371
Weighted average common shares outstanding (in shares)	150,565	148,708	150,983	148,607
Effect of dilutive common stock awards (in shares)	1,815	1,265	2,081	1,038
Effect of dilutive common stock warrants (in shares)	588	0	718	0
Diluted weighted average common shares outstanding (in shares)	152,968	149,973	153,782	149,645
Basic earnings (loss) per common share (in usd per share)	$ 0.41	$ 0.34	$ 1.13	$ 0.92
Diluted earnings (loss) per common share (in usd per share)	$ 0.41	$ 0.34	$ 1.11	$ 0.92

Earnings Per Common Share (Text

Earnings Per Common Share (Textual) (Details) - shares shares in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Warrant [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount		4		4
Employee Stock Option [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	1	4	1	4

Stock-Based Compensation, Stock

Stock-Based Compensation, Stock Option Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2017	Dec. 31, 2016
Fair value assumptions of stock options
Dividend yield	2.00%	2.50%
Risk-free interest rate	2.00%	2.00%
Weighted average expected volatility	25.00%	25.00%
Weighted average expected life	5 years 6 months	5 years 6 months
Weighted average per share fair value of stock options (in usd per share)	$ 5.30	$ 3.36
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Stock Options Shares Outstanding, Beginning balance (in shares)	6,357,843
Granted (in shares)	799,558
Exercised (in shares)	(1,291,244)
Forfeited or expired (in shares)	(506,395)
Stock Options Shares Outstanding, Ending balance (in shares)	5,359,762	6,357,843
Options exercisable (in shares)	3,072,811
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract]
Stock Options Outstanding, Weighted Average Exercise Price, Beginning balance (in usd per share)	$ 17.67
Granted, Weighted Average Exercise Price (in usd per share)	25.61
Exercised, Weighted Average Exercise Price (in usd per share)	16.32
Forfeited or expired, Weighted Average Exercise Price (in usd per share)	31.90
Stock Options Outstanding, Weighted Average Exercise Price, Ending balance (in usd per share)	18.07	$ 17.67
Options Exercisable, Weighted Average Exercise Price (in usd per share)	$ 16.54
Stock Options Outstanding, Weighted Average Remaining Contractual Term	6 years 6 months 18 days	6 years 1 month 6 days
Options exercisable, Weighted Average Remaining Contractual Term	5 years 3 months
Stock Options Outstanding, Aggregate Intrinsic Value	$ 34,334	$ 47,902
Options exercisable, Aggregate Intrinsic Value	$ 23,911

Stock-Based Compensation, Restr

Stock-Based Compensation, Restricted Stock Activity (Details)	9 Months Ended
	Sep. 30, 2017$ / sharesshares
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Outstanding Shares, Beginning balance (in shares) | shares	2,377,380
Granted (in shares) | shares	748,024
Vested (in shares) | shares	(872,020)
Forfeited (in shares) | shares	(101,703)
Outstanding Shares, Ending balance (in shares) | shares	2,151,681
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Outstanding, Weighted Average Grant Date Fair Value, Beginning balance (in usd per share) | $ / shares	$ 17.40
Granted, Weighted Average Grant Date Fair Value (in usd per share) | $ / shares	25.55
Vested, Weighted Average Grant Date Fair Value (in usd per share) | $ / shares	17.92
Forfeited, Weighted Average Grant Date Fair Value (in usd per share) | $ / shares	20.02
Outstanding Weighted Average Grant Date Fair Value, Ending balance (in usd per share) | $ / shares	$ 19.94

Stock-Based Compensation (Detai

Stock-Based Compensation (Details Textuals) - USD ($)	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Stock Based Compensation (Textuals) [Abstract]
Intrinsic value of stock options exercised	$ 12,000,000	$ 2,000,000
Total fair value of vested stock options	$ 4,000,000	$ 3,000,000
Service-based Restricted Stock Award
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period	4 years	4 years
Performance-based Restricted Stock Award
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period	3 years	3 years
Employee Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Recognized compensation expense for accelerated vesting of stock options	$ 570,000
Recognized compensation expense for vesting of stock options	3,000,000	$ 3,000,000
Unvested share-based payment awards	$ 5,000,000
Employee Service Share Based Compensation Nonvested Awards Compensation Cost Not Yet Recognized Year For Recognition	first quarter 2021
Restricted Stock Award
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Recognized compensation expense for accelerated vesting of stock options	$ 2,000,000
Recognized compensation expense for vesting of stock options	14,000,000	$ 15,000,000
Unvested share-based payment awards	$ 22,000,000
Employee Service Share Based Compensation Nonvested Awards Compensation Cost Not Yet Recognized Year For Recognition	first quarter 2021

Investment Securities, AFS and

Investment Securities, AFS and HTM Securities Amortized Costs and Fair Values (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Investment securities available for sale:
Amortized Cost	$ 3,829,984	$ 4,724,895
Gross Unrealized Gains	15,552	19,132
Gross Unrealized Losses	(43,837)	(63,801)
Fair Value	3,801,699	4,680,226
Investment securities held to maturity:
Amortized Cost	2,233,579	1,273,536
Gross Unrealized Gains	28,951	4,523
Gross Unrealized Losses	(18,685)	(13,385)
Fair Value	2,243,845	1,264,674
US Treasury Securities
Investment securities available for sale:
Amortized Cost	1,003	1,000
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(2)	0
Fair Value	1,001	1,000
Obligations of state and political subdivisions (municipal securities)
Investment securities held to maturity:
Amortized Cost	1,192,290	1,145,843
Gross Unrealized Gains	14,525	3,868
Gross Unrealized Losses	(3,858)	(12,036)
Fair Value	1,202,957	1,137,675
Private Label
Investment securities available for sale:
Amortized Cost	1,083	1,134
Gross Unrealized Gains	0	1
Gross Unrealized Losses	(11)	(14)
Fair Value	1,072	1,121
Investment securities held to maturity:
Amortized Cost	0
Fair Value	0
GNMA Commercial Mortgage-Related Securities
Investment securities available for sale:
Amortized Cost	1,539,169	2,064,508
Gross Unrealized Gains	73	356
Gross Unrealized Losses	(26,165)	(35,966)
Fair Value	1,513,077	2,028,898
Investment securities held to maturity:
Amortized Cost	554,707
Gross Unrealized Gains	10,250
Gross Unrealized Losses	(11,808)
Fair Value	553,149
Asset backed Securities
Investment securities available for sale:
Amortized Cost	108,590
Gross Unrealized Gains	63
Gross Unrealized Losses	(25)
Fair Value	108,628
Investment securities held to maturity:
Amortized Cost	0
Fair Value	0
Other Debt And Other Equity Securities
Investment securities available for sale:
Amortized Cost	4,718	4,718
Gross Unrealized Gains	132	105
Gross Unrealized Losses	(26)	(21)
Fair Value	4,824	4,802
FNMA and FHLMC | Residential Related Securities
Investment securities available for sale:
Amortized Cost	494,041	625,234
Gross Unrealized Gains	12,780	17,298
Gross Unrealized Losses	(1,560)	(2,602)
Fair Value	505,261	639,930
Investment securities held to maturity:
Amortized Cost	42,386	37,697
Gross Unrealized Gains	464	439
Gross Unrealized Losses	(404)	(693)
Fair Value	42,446	37,443
GNMA | Residential Related Securities
Investment securities available for sale:
Amortized Cost	1,681,380	2,028,301
Gross Unrealized Gains	2,504	1,372
Gross Unrealized Losses	(16,048)	(25,198)
Fair Value	1,667,836	2,004,475
Investment securities held to maturity:
Amortized Cost	444,196	89,996
Gross Unrealized Gains	3,712	216
Gross Unrealized Losses	(2,615)	(656)
Fair Value	$ 445,293	$ 89,556

Investment Securities, AFS an47

Investment Securities, AFS and HTM Contractual Maturities (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Amortized Cost
Available for Sale, Due in one year or less	$ 1,000
Available for Sale, Due after one year through five years	4,703
Available for Sale, Due after five years through ten years	0
Available for Sale, Due after ten years	0
Available for Sale, Total debt securities	5,703
Investment securities available for sale, amortized cost	3,829,984	$ 4,724,895
Fair Value
Available for Sale, Due in one year or less	1,000
Available for Sale, Due after one year through five years	4,675
Available for Sale, Due after five years through ten years	0
Available for Sale, Due after ten years	0
Available for Sale, Total debt securities	5,675
Investment securities available for sale, at fair value	$ 3,801,699	4,680,226
Ratio of Fair Value to Amortized Cost	99.30%
Amortized Cost
Held to Maturity, Due in one year or less	$ 54,259
Held to Maturity, Due after one year through five years	222,037
Held to Maturity, Due after five years through ten years	281,559
Held to Maturity, Due after ten years	634,435
Held to Maturity, Debt Securities, Amortized Cost Basis	1,192,290
Held to Maturity Amortized Cost	2,233,579	1,273,536
Fair Value
Held to Maturity, Due in one year or less	48,123
Held to Maturity, Due after one year through five years	227,978
Held to Maturity, Due after five years through ten years	284,789
Held to Maturity, Due after ten years	642,067
Held to Maturity, Securities, Debt Securities	1,202,957
Held to Maturity, Total debt securities	$ 2,243,845	1,264,674
Ratio of Fair Value to Amortized Cost	100.50%
Private Label
Amortized Cost
Investment securities available for sale, amortized cost	$ 1,083	1,134
Fair Value
Investment securities available for sale, at fair value	1,072	1,121
Amortized Cost
Held to Maturity Amortized Cost	0
Fair Value
Held to Maturity, Total debt securities	0
GNMA Commercial Mortgage-Related Securities
Amortized Cost
Investment securities available for sale, amortized cost	1,539,169	2,064,508
Fair Value
Investment securities available for sale, at fair value	1,513,077	2,028,898
Amortized Cost
Held to Maturity Amortized Cost	554,707
Fair Value
Held to Maturity, Total debt securities	553,149
Asset backed Securities
Amortized Cost
Investment securities available for sale, amortized cost	108,590
Fair Value
Investment securities available for sale, at fair value	108,628
Amortized Cost
Held to Maturity Amortized Cost	0
Fair Value
Held to Maturity, Total debt securities	0
Equity Securities [Member]
Amortized Cost
Investment securities available for sale, amortized cost	18
Fair Value
Investment securities available for sale, at fair value	150
Amortized Cost
Held to Maturity Amortized Cost	0
Fair Value
Held to Maturity, Total debt securities	0
FNMA and FHLMC | Residential Related Securities
Amortized Cost
Investment securities available for sale, amortized cost	494,041	625,234
Fair Value
Investment securities available for sale, at fair value	505,261	639,930
Amortized Cost
Held to Maturity Amortized Cost	42,386	37,697
Fair Value
Held to Maturity, Total debt securities	42,446	37,443
GNMA | Residential Related Securities
Amortized Cost
Investment securities available for sale, amortized cost	1,681,380	2,028,301
Fair Value
Investment securities available for sale, at fair value	1,667,836	2,004,475
Amortized Cost
Held to Maturity Amortized Cost	444,196	89,996
Fair Value
Held to Maturity, Total debt securities	$ 445,293	$ 89,556

Investment Securities, Gains, L

Investment Securities, Gains, Losses, and Proceeds (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Available-for-sale Securities, Gross Realized Gain (Loss) [Abstract]
Gross gains on available for sale securities	$ 0	$ 6,403
Gross gains on held to maturity securities	364	0
Total gains	364	6,403
Gross losses on available for sale securities	0	(202)
Gross losses on held to maturity securities	(5)	0
Total losses	(5)	(202)
Total investment securities gains, net	359	6,201
Proceeds from sales of securities	$ 16,059	$ 359,591

Investment Securities, AFS an49

Investment Securities, AFS and HTM Securities Gross Unrealized Losses (Details) $ in Thousands	Sep. 30, 2017USD ($)security	Dec. 31, 2016USD ($)security
Unrealized losses and fair value of available for sale securities , by investment category and time length
Unrealized losses on available for sale securities, less than 12 months	$ (15,724)	$ (44,266)
Unrealized losses on available for sale securities, 12 months or more	(28,113)	(19,535)
Total unrealized losses on available for sale securities	(43,837)	(63,801)
Fair value of unrealized losses on available for sale securities, less than 12 months	1,471,455	3,397,143
Fair value of unrealized losses on available for sale securities, 12 months or more	1,304,549	430,377
Total fair value of unrealized losses on available for sale securities	$ 2,776,004	$ 3,827,520
Number of available for sale securities in a continuous unrealized loss position less than twelve months | security	87	145
Number of available for sale securities in a continuous unrealized loss position for twelve months or more | security	73	22
Held-to-maturity Securities Continuous Unrealized Loss Position [Abstract]
Unrealized losses on held to maturity securities, less than 12 months	$ (3,788)	$ (13,034)
Unrealized losses on held to maturity securities, 12 months or more	(14,897)	(351)
Total unrealized losses on held to maturity securities	$ (18,685)	$ (13,385)
Held-to-maturity, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions, 12 Months or Longer | security	138	5
Fair value of unrealized losses on held to maturity securities, less than 12 months	$ 474,131	$ 496,296
Fair value of unrealized losses on held to maturity securities, 12 months or more	599,484	7,783
Total fair value of unrealized losses on held to maturity securities	$ 1,073,615	$ 504,079
Held-to-maturity, Securities In Unrealized Loss Positions Qualitative Disclosure Number Of Positions, less than 12 Months | security	241	753
US Treasury Securities
Unrealized losses and fair value of available for sale securities , by investment category and time length
Unrealized losses on available for sale securities, less than 12 months	$ (2)
Unrealized losses on available for sale securities, 12 months or more	0
Total unrealized losses on available for sale securities	(2)
Fair value of unrealized losses on available for sale securities, less than 12 months	1,001
Fair value of unrealized losses on available for sale securities, 12 months or more	0
Total fair value of unrealized losses on available for sale securities	$ 1,001
Number of available for sale securities in a continuous unrealized loss position less than twelve months | security	1
Number of available for sale securities in a continuous unrealized loss position for twelve months or more | security	0
Obligations of state and political subdivisions (municipal securities)
Held-to-maturity Securities Continuous Unrealized Loss Position [Abstract]
Unrealized losses on held to maturity securities, less than 12 months	$ (1,195)	$ (11,937)
Unrealized losses on held to maturity securities, 12 months or more	(2,663)	(99)
Total unrealized losses on held to maturity securities	(3,858)	(12,036)
Fair value of unrealized losses on held to maturity securities, less than 12 months	138,178	414,186
Fair value of unrealized losses on held to maturity securities, 12 months or more	94,432	1,752
Total fair value of unrealized losses on held to maturity securities	$ 232,610	$ 415,938
Obligations of state and political subdivisions (municipal securities) | Held To Maturity Securities In Unrealized Loss Positions Qualitative Disclosure Number Of Positions Less Than One Year [Member]
Held-to-maturity Securities Continuous Unrealized Loss Position [Abstract]
Number of held to maturity securities in a continuous unrealized loss position | security	195	700
Obligations of state and political subdivisions (municipal securities) | Held To Maturity Securities In Unrealized Loss Positions Qualitative Disclosure Number Of Positions Greater Than Or Equal To One Year [Member]
Held-to-maturity Securities Continuous Unrealized Loss Position [Abstract]
Number of held to maturity securities in a continuous unrealized loss position | security	108	4
Private Label
Unrealized losses and fair value of available for sale securities , by investment category and time length
Unrealized losses on available for sale securities, less than 12 months	$ 0	$ 0
Unrealized losses on available for sale securities, 12 months or more	(11)	(14)
Total unrealized losses on available for sale securities	(11)	(14)
Fair value of unrealized losses on available for sale securities, less than 12 months	0	0
Fair value of unrealized losses on available for sale securities, 12 months or more	1,072	1,119
Total fair value of unrealized losses on available for sale securities	$ 1,072	$ 1,119
Number of available for sale securities in a continuous unrealized loss position less than twelve months | security	0	0
Number of available for sale securities in a continuous unrealized loss position for twelve months or more | security	1	1
GNMA Commercial Mortgage-Related Securities
Unrealized losses and fair value of available for sale securities , by investment category and time length
Unrealized losses on available for sale securities, less than 12 months	$ (4,962)	$ (16,445)
Unrealized losses on available for sale securities, 12 months or more	(21,203)	(19,521)
Total unrealized losses on available for sale securities	(26,165)	(35,966)
Fair value of unrealized losses on available for sale securities, less than 12 months	551,833	1,427,889
Fair value of unrealized losses on available for sale securities, 12 months or more	891,178	429,258
Total fair value of unrealized losses on available for sale securities	$ 1,443,011	$ 1,857,147
Number of available for sale securities in a continuous unrealized loss position less than twelve months | security	42	74
Number of available for sale securities in a continuous unrealized loss position for twelve months or more | security	56	21
Held-to-maturity Securities Continuous Unrealized Loss Position [Abstract]
Unrealized losses on held to maturity securities, less than 12 months	$ (841)
Unrealized losses on held to maturity securities, 12 months or more	(10,967)
Total unrealized losses on held to maturity securities	(11,808)
Fair value of unrealized losses on held to maturity securities, less than 12 months	94,758
Fair value of unrealized losses on held to maturity securities, 12 months or more	427,161
Total fair value of unrealized losses on held to maturity securities	$ 521,919
GNMA Commercial Mortgage-Related Securities | Held To Maturity Securities In Unrealized Loss Positions Qualitative Disclosure Number Of Positions Less Than One Year [Member]
Held-to-maturity Securities Continuous Unrealized Loss Position [Abstract]
Number of held to maturity securities in a continuous unrealized loss position | security	5
GNMA Commercial Mortgage-Related Securities | Held To Maturity Securities In Unrealized Loss Positions Qualitative Disclosure Number Of Positions Greater Than Or Equal To One Year [Member]
Held-to-maturity Securities Continuous Unrealized Loss Position [Abstract]
Number of held to maturity securities in a continuous unrealized loss position | security	19
Asset backed Securities
Unrealized losses and fair value of available for sale securities , by investment category and time length
Unrealized losses on available for sale securities, less than 12 months	$ (25)
Unrealized losses on available for sale securities, 12 months or more	0
Total unrealized losses on available for sale securities	(25)
Fair value of unrealized losses on available for sale securities, less than 12 months	52,851
Fair value of unrealized losses on available for sale securities, 12 months or more	0
Total fair value of unrealized losses on available for sale securities	$ 52,851
Number of available for sale securities in a continuous unrealized loss position less than twelve months | security	5
Number of available for sale securities in a continuous unrealized loss position for twelve months or more | security	0
Other Debt And Other Equity Securities
Unrealized losses and fair value of available for sale securities , by investment category and time length
Unrealized losses on available for sale securities, less than 12 months	$ (26)	$ (21)
Unrealized losses on available for sale securities, 12 months or more	0	0
Total unrealized losses on available for sale securities	(26)	(21)
Fair value of unrealized losses on available for sale securities, less than 12 months	174	1,479
Fair value of unrealized losses on available for sale securities, 12 months or more	0	0
Total fair value of unrealized losses on available for sale securities	$ 174	$ 1,479
Number of available for sale securities in a continuous unrealized loss position less than twelve months | security	1	3
Number of available for sale securities in a continuous unrealized loss position for twelve months or more | security	0	0
FNMA and FHLMC | Residential Related Securities
Unrealized losses and fair value of available for sale securities , by investment category and time length
Unrealized losses on available for sale securities, less than 12 months	$ (1,254)	$ (2,602)
Unrealized losses on available for sale securities, 12 months or more	(306)	0
Total unrealized losses on available for sale securities	(1,560)	(2,602)
Fair value of unrealized losses on available for sale securities, less than 12 months	177,782	244,252
Fair value of unrealized losses on available for sale securities, 12 months or more	33,842	0
Total fair value of unrealized losses on available for sale securities	$ 211,624	$ 244,252
Number of available for sale securities in a continuous unrealized loss position less than twelve months | security	16	14
Number of available for sale securities in a continuous unrealized loss position for twelve months or more | security	2	0
Held-to-maturity Securities Continuous Unrealized Loss Position [Abstract]
Unrealized losses on held to maturity securities, less than 12 months	$ (124)	$ (441)
Unrealized losses on held to maturity securities, 12 months or more	(280)	(252)
Total unrealized losses on held to maturity securities	(404)	(693)
Fair value of unrealized losses on held to maturity securities, less than 12 months	17,816	17,477
Fair value of unrealized losses on held to maturity securities, 12 months or more	9,910	6,031
Total fair value of unrealized losses on held to maturity securities	$ 27,726	$ 23,508
FNMA and FHLMC | Residential Related Securities | Held To Maturity Securities In Unrealized Loss Positions Qualitative Disclosure Number Of Positions Less Than One Year [Member]
Held-to-maturity Securities Continuous Unrealized Loss Position [Abstract]
Number of held to maturity securities in a continuous unrealized loss position | security	12	14
FNMA and FHLMC | Residential Related Securities | Held To Maturity Securities In Unrealized Loss Positions Qualitative Disclosure Number Of Positions Greater Than Or Equal To One Year [Member]
Held-to-maturity Securities Continuous Unrealized Loss Position [Abstract]
Number of held to maturity securities in a continuous unrealized loss position | security	4	1
GNMA | Residential Related Securities
Unrealized losses and fair value of available for sale securities , by investment category and time length
Unrealized losses on available for sale securities, less than 12 months	$ (9,455)	$ (25,198)
Unrealized losses on available for sale securities, 12 months or more	(6,593)	0
Total unrealized losses on available for sale securities	(16,048)	(25,198)
Fair value of unrealized losses on available for sale securities, less than 12 months	687,814	1,723,523
Fair value of unrealized losses on available for sale securities, 12 months or more	378,457	0
Total fair value of unrealized losses on available for sale securities	$ 1,066,271	$ 1,723,523
Number of available for sale securities in a continuous unrealized loss position less than twelve months | security	22	54
Number of available for sale securities in a continuous unrealized loss position for twelve months or more | security	14	0
Held-to-maturity Securities Continuous Unrealized Loss Position [Abstract]
Unrealized losses on held to maturity securities, less than 12 months	$ (1,628)	$ (656)
Unrealized losses on held to maturity securities, 12 months or more	(987)	0
Total unrealized losses on held to maturity securities	(2,615)	(656)
Fair value of unrealized losses on held to maturity securities, less than 12 months	223,379	64,633
Fair value of unrealized losses on held to maturity securities, 12 months or more	67,981	0
Total fair value of unrealized losses on held to maturity securities	$ 291,360	$ 64,633
GNMA | Residential Related Securities | Held To Maturity Securities In Unrealized Loss Positions Qualitative Disclosure Number Of Positions Less Than One Year [Member]
Held-to-maturity Securities Continuous Unrealized Loss Position [Abstract]
Number of held to maturity securities in a continuous unrealized loss position | security	29	39
GNMA | Residential Related Securities | Held To Maturity Securities In Unrealized Loss Positions Qualitative Disclosure Number Of Positions Greater Than Or Equal To One Year [Member]
Held-to-maturity Securities Continuous Unrealized Loss Position [Abstract]
Number of held to maturity securities in a continuous unrealized loss position | security	7	0

Investment Securities (Details

Investment Securities (Details Textual) - USD ($)	9 Months Ended
	Sep. 30, 2017	Dec. 31, 2016
Investment Securities (Textuals) [Abstract]
Available-for-sale Securities, Transferred to Held-to-maturity Securities, at Carrying Value	$ 1,000,000,000
Asset-Backed Securities, at Carrying Value	109,000,000
Held-to-maturity Securities, Sold Security, at Carrying Value	16,000,000
Held-to-maturity Securities, Sold Security, Realized Gain (Loss)	359,000
Securities pledged as collateral	2,900,000,000	$ 1,800,000,000
Federal Home Loan Bank Stock	97,000,000	65,000,000
Federal Reserve Bank Stock	$ 76,000,000	$ 75,000,000

Loans, Loan Composition (Detail

Loans, Loan Composition (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Loans and Leases Receivable Disclosure [Line Items]
Total loans	$ 20,931,460	$ 20,054,716
Commercial and industrial
Loans and Leases Receivable Disclosure [Line Items]
Total loans	6,534,660	6,489,014
Commercial real estate — owner occupied
Loans and Leases Receivable Disclosure [Line Items]
Total loans	827,064	897,724
Commercial and business lending
Loans and Leases Receivable Disclosure [Line Items]
Total loans	7,361,724	7,386,738
Commercial real estate — investor
Loans and Leases Receivable Disclosure [Line Items]
Total loans	3,345,536	3,574,732
Real estate construction
Loans and Leases Receivable Disclosure [Line Items]
Total loans	1,552,135	1,432,497
Commercial real estate lending
Loans and Leases Receivable Disclosure [Line Items]
Total loans	4,897,671	5,007,229
Total commercial
Loans and Leases Receivable Disclosure [Line Items]
Total loans	12,259,395	12,393,967
Residential mortgage
Loans and Leases Receivable Disclosure [Line Items]
Total loans	7,408,471	6,332,327
Home equity
Loans and Leases Receivable Disclosure [Line Items]
Total loans	890,130	934,443
Other consumer
Loans and Leases Receivable Disclosure [Line Items]
Total loans	373,464	393,979
Total consumer
Loans and Leases Receivable Disclosure [Line Items]
Total loans	$ 8,672,065	$ 7,660,749

Loans Loans, Loans by Credit Qu

Loans Loans, Loans by Credit Quality Indicator (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Financing Receivable, Recorded Investment [Line Items]
Loans	$ 20,931,460	$ 20,054,716
Pass
Financing Receivable, Recorded Investment [Line Items]
Loans	20,279,634	19,251,353
Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans	182,400	176,918
Potential Problem
Financing Receivable, Recorded Investment [Line Items]
Loans	258,909	351,142
Nonaccrual
Financing Receivable, Recorded Investment [Line Items]
Loans	210,517	275,303
Commercial and industrial
Financing Receivable, Recorded Investment [Line Items]
Loans	6,534,660	6,489,014
Commercial and industrial | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans	6,101,491	5,937,119
Commercial and industrial | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans	157,106	141,328
Commercial and industrial | Potential Problem
Financing Receivable, Recorded Investment [Line Items]
Loans	153,779	227,196
Commercial and industrial | Nonaccrual
Financing Receivable, Recorded Investment [Line Items]
Loans	122,284	183,371
Commercial real estate — owner occupied
Financing Receivable, Recorded Investment [Line Items]
Loans	827,064	897,724
Commercial real estate — owner occupied | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans	742,257	805,871
Commercial real estate — owner occupied | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans	11,741	17,785
Commercial real estate — owner occupied | Potential Problem
Financing Receivable, Recorded Investment [Line Items]
Loans	57,468	64,524
Commercial real estate — owner occupied | Nonaccrual
Financing Receivable, Recorded Investment [Line Items]
Loans	15,598	9,544
Commercial and business lending
Financing Receivable, Recorded Investment [Line Items]
Loans	7,361,724	7,386,738
Commercial and business lending | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans	6,843,748	6,742,990
Commercial and business lending | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans	168,847	159,113
Commercial and business lending | Potential Problem
Financing Receivable, Recorded Investment [Line Items]
Loans	211,247	291,720
Commercial and business lending | Nonaccrual
Financing Receivable, Recorded Investment [Line Items]
Loans	137,882	192,915
Commercial real estate — investor
Financing Receivable, Recorded Investment [Line Items]
Loans	3,345,536	3,574,732
Commercial real estate — investor | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans	3,284,497	3,491,217
Commercial real estate — investor | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans	10,726	14,236
Commercial real estate — investor | Potential Problem
Financing Receivable, Recorded Investment [Line Items]
Loans	46,770	51,228
Commercial real estate — investor | Nonaccrual
Financing Receivable, Recorded Investment [Line Items]
Loans	3,543	18,051
Real estate construction
Financing Receivable, Recorded Investment [Line Items]
Loans	1,552,135	1,432,497
Real estate construction | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans	1,550,462	1,429,083
Real estate construction | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans	15	105
Real estate construction | Potential Problem
Financing Receivable, Recorded Investment [Line Items]
Loans	118	2,465
Real estate construction | Nonaccrual
Financing Receivable, Recorded Investment [Line Items]
Loans	1,540	844
Commercial real estate lending
Financing Receivable, Recorded Investment [Line Items]
Loans	4,897,671	5,007,229
Commercial real estate lending | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans	4,834,959	4,920,300
Commercial real estate lending | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans	10,741	14,341
Commercial real estate lending | Potential Problem
Financing Receivable, Recorded Investment [Line Items]
Loans	46,888	53,693
Commercial real estate lending | Nonaccrual
Financing Receivable, Recorded Investment [Line Items]
Loans	5,083	18,895
Total commercial
Financing Receivable, Recorded Investment [Line Items]
Loans	12,259,395	12,393,967
Total commercial | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans	11,678,707	11,663,290
Total commercial | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans	179,588	173,454
Total commercial | Potential Problem
Financing Receivable, Recorded Investment [Line Items]
Loans	258,135	345,413
Total commercial | Nonaccrual
Financing Receivable, Recorded Investment [Line Items]
Loans	142,965	211,810
Residential mortgage
Financing Receivable, Recorded Investment [Line Items]
Loans	7,408,471	6,332,327
Residential mortgage | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans	7,352,286	6,275,162
Residential mortgage | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans	881	1,314
Residential mortgage | Potential Problem
Financing Receivable, Recorded Investment [Line Items]
Loans	650	5,615
Residential mortgage | Nonaccrual
Financing Receivable, Recorded Investment [Line Items]
Loans	54,654	50,236
Home equity
Financing Receivable, Recorded Investment [Line Items]
Loans	890,130	934,443
Home equity | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans	876,003	919,740
Home equity | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans	1,364	1,588
Home equity | Potential Problem
Financing Receivable, Recorded Investment [Line Items]
Loans	124	114
Home equity | Nonaccrual
Financing Receivable, Recorded Investment [Line Items]
Loans	12,639	13,001
Other consumer
Financing Receivable, Recorded Investment [Line Items]
Loans	373,464	393,979
Other consumer | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans	372,638	393,161
Other consumer | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans	567	562
Other consumer | Potential Problem
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Other consumer | Nonaccrual
Financing Receivable, Recorded Investment [Line Items]
Loans	259	256
Total consumer
Financing Receivable, Recorded Investment [Line Items]
Loans	8,672,065	7,660,749
Total consumer | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans	8,600,927	7,588,063
Total consumer | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans	2,812	3,464
Total consumer | Potential Problem
Financing Receivable, Recorded Investment [Line Items]
Loans	774	5,729
Total consumer | Nonaccrual
Financing Receivable, Recorded Investment [Line Items]
Loans	$ 67,552	$ 63,493

Loans, Loans by Past Due Status

Loans, Loans by Past Due Status (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Summarized details of Loans
Current	$ 20,696,876	$ 19,756,523
Nonaccrual	210,517	275,303
Total loans	20,931,460	20,054,716
Accruing loans past due 90 days or more	2,000	2,000
Nonaccrual Loans, Current Portion	$ 156,000	$ 224,000
Percent of current nonaccrual loans	74.00%	81.00%
30-59 Days Past Due
Summarized details of Loans
Total Past Due	$ 19,736	$ 16,662
60-89 Days Past Due
Summarized details of Loans
Total Past Due	2,720	4,615
90 Days or More Past Due
Summarized details of Loans
Total Past Due	1,611	1,613
Commercial and industrial
Summarized details of Loans
Current	6,410,690	6,303,994
Nonaccrual	122,284	183,371
Total loans	6,534,660	6,489,014
Commercial and industrial | 30-59 Days Past Due
Summarized details of Loans
Total Past Due	1,254	965
Commercial and industrial | 60-89 Days Past Due
Summarized details of Loans
Total Past Due	124	448
Commercial and industrial | 90 Days or More Past Due
Summarized details of Loans
Total Past Due	308	236
Commercial real estate — owner occupied
Summarized details of Loans
Current	809,944	886,796
Nonaccrual	15,598	9,544
Total loans	827,064	897,724
Commercial real estate — owner occupied | 30-59 Days Past Due
Summarized details of Loans
Total Past Due	1,522	968
Commercial real estate — owner occupied | 60-89 Days Past Due
Summarized details of Loans
Total Past Due	0	416
Commercial real estate — owner occupied | 90 Days or More Past Due
Summarized details of Loans
Total Past Due	0	0
Commercial and business lending
Summarized details of Loans
Current	7,220,634	7,190,790
Nonaccrual	137,882	192,915
Total loans	7,361,724	7,386,738
Commercial and business lending | 30-59 Days Past Due
Summarized details of Loans
Total Past Due	2,776	1,933
Commercial and business lending | 60-89 Days Past Due
Summarized details of Loans
Total Past Due	124	864
Commercial and business lending | 90 Days or More Past Due
Summarized details of Loans
Total Past Due	308	236
Commercial real estate — investor
Summarized details of Loans
Current	3,340,884	3,555,750
Nonaccrual	3,543	18,051
Total loans	3,345,536	3,574,732
Commercial real estate — investor | 30-59 Days Past Due
Summarized details of Loans
Total Past Due	1,109	431
Commercial real estate — investor | 60-89 Days Past Due
Summarized details of Loans
Total Past Due	0	500
Commercial real estate — investor | 90 Days or More Past Due
Summarized details of Loans
Total Past Due	0	0
Real estate construction
Summarized details of Loans
Current	1,549,895	1,431,284
Nonaccrual	1,540	844
Total loans	1,552,135	1,432,497
Real estate construction | 30-59 Days Past Due
Summarized details of Loans
Total Past Due	685	264
Real estate construction | 60-89 Days Past Due
Summarized details of Loans
Total Past Due	15	105
Real estate construction | 90 Days or More Past Due
Summarized details of Loans
Total Past Due	0	0
Commercial real estate lending
Summarized details of Loans
Current	4,890,779	4,987,034
Nonaccrual	5,083	18,895
Total loans	4,897,671	5,007,229
Commercial real estate lending | 30-59 Days Past Due
Summarized details of Loans
Total Past Due	1,794	695
Commercial real estate lending | 60-89 Days Past Due
Summarized details of Loans
Total Past Due	15	605
Commercial real estate lending | 90 Days or More Past Due
Summarized details of Loans
Total Past Due	0	0
Total commercial
Summarized details of Loans
Current	12,111,413	12,177,824
Nonaccrual	142,965	211,810
Total loans	12,259,395	12,393,967
Total commercial | 30-59 Days Past Due
Summarized details of Loans
Total Past Due	4,570	2,628
Total commercial | 60-89 Days Past Due
Summarized details of Loans
Total Past Due	139	1,469
Total commercial | 90 Days or More Past Due
Summarized details of Loans
Total Past Due	308	236
Residential mortgage
Summarized details of Loans
Current	7,344,947	6,273,949
Nonaccrual	54,654	50,236
Total loans	7,408,471	6,332,327
Residential mortgage | 30-59 Days Past Due
Summarized details of Loans
Total Past Due	8,327	7,298
Residential mortgage | 60-89 Days Past Due
Summarized details of Loans
Total Past Due	543	844
Residential mortgage | 90 Days or More Past Due
Summarized details of Loans
Total Past Due	0	0
Home equity
Summarized details of Loans
Current	870,300	915,593
Nonaccrual	12,639	13,001
Total loans	890,130	934,443
Home equity | 30-59 Days Past Due
Summarized details of Loans
Total Past Due	5,852	4,265
Home equity | 60-89 Days Past Due
Summarized details of Loans
Total Past Due	1,339	1,584
Home equity | 90 Days or More Past Due
Summarized details of Loans
Total Past Due	0	0
Other consumer
Summarized details of Loans
Current	370,216	389,157
Nonaccrual	259	256
Total loans	373,464	393,979
Other consumer | 30-59 Days Past Due
Summarized details of Loans
Total Past Due	987	2,471
Other consumer | 60-89 Days Past Due
Summarized details of Loans
Total Past Due	699	718
Other consumer | 90 Days or More Past Due
Summarized details of Loans
Total Past Due	1,303	1,377
Total consumer
Summarized details of Loans
Current	8,585,463	7,578,699
Nonaccrual	67,552	63,493
Total loans	8,672,065	7,660,749
Total consumer | 30-59 Days Past Due
Summarized details of Loans
Total Past Due	15,166	14,034
Total consumer | 60-89 Days Past Due
Summarized details of Loans
Total Past Due	2,581	3,146
Total consumer | 90 Days or More Past Due
Summarized details of Loans
Total Past Due	$ 1,303	$ 1,377

Loans, Impaired Loans Recorded

Loans, Impaired Loans Recorded Investment, Unpaid Principal Balance, Related Allowance, Average Recorded Investment, and Interest Income Recognized (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2017	Dec. 31, 2016
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	$ 252,542	$ 316,735
Unpaid Principal Balance	275,458	349,045
Related Allowance	25,671	35,054
Average Recorded Investment	275,589	333,439
Interest Income Recognized	$ 5,190	$ 8,784
Net Recorded Investment of the Impaired Loans	82.00%	81.00%
Loans with a related allowance
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	$ 151,058	$ 182,587
Unpaid Principal Balance	159,695	191,333
Related Allowance	25,671	35,054
Average Recorded Investment	160,317	192,891
Interest Income Recognized	4,158	6,939
Loans with no related allowance
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	101,484	134,148
Unpaid Principal Balance	115,763	157,712
Related Allowance	0	0
Average Recorded Investment	115,272	140,548
Interest Income Recognized	1,032	1,845
Commercial and industrial
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	154,028	213,271
Unpaid Principal Balance	171,823	240,038
Related Allowance	11,540	21,047
Average Recorded Investment	176,480	222,788
Interest Income Recognized	1,977	3,864
Commercial and industrial | Loans with a related allowance
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	67,226	99,786
Unpaid Principal Balance	72,343	105,175
Related Allowance	11,540	21,047
Average Recorded Investment	76,082	104,808
Interest Income Recognized	1,050	2,345
Commercial and industrial | Loans with no related allowance
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	86,802	113,485
Unpaid Principal Balance	99,480	134,863
Related Allowance	0	0
Average Recorded Investment	100,398	117,980
Interest Income Recognized	927	1,519
Commercial real estate — owner occupied
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	19,126	13,983
Unpaid Principal Balance	20,090	14,834
Related Allowance	1,549	23
Average Recorded Investment	19,048	14,599
Interest Income Recognized	192	401
Commercial real estate — owner occupied | Loans with a related allowance
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	12,255	5,544
Unpaid Principal Balance	12,374	5,568
Related Allowance	1,549	23
Average Recorded Investment	12,032	5,840
Interest Income Recognized	192	263
Commercial real estate — owner occupied | Loans with no related allowance
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	6,871	8,439
Unpaid Principal Balance	7,716	9,266
Related Allowance	0	0
Average Recorded Investment	7,016	8,759
Interest Income Recognized	0	138
Commercial and business lending
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	173,154	227,254
Unpaid Principal Balance	191,913	254,872
Related Allowance	13,089	21,070
Average Recorded Investment	195,528	237,387
Interest Income Recognized	2,169	4,265
Commercial and business lending | Loans with a related allowance
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	79,481	105,330
Unpaid Principal Balance	84,717	110,743
Related Allowance	13,089	21,070
Average Recorded Investment	88,114	110,648
Interest Income Recognized	1,242	2,608
Commercial and business lending | Loans with no related allowance
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	93,673	121,924
Unpaid Principal Balance	107,196	144,129
Related Allowance	0	0
Average Recorded Investment	107,414	126,739
Interest Income Recognized	927	1,657
Commercial real estate — investor
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	17,563	32,908
Unpaid Principal Balance	17,720	33,509
Related Allowance	1,812	3,410
Average Recorded Investment	17,598	37,757
Interest Income Recognized	1,224	2,120
Commercial real estate — investor | Loans with a related allowance
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	16,974	26,764
Unpaid Principal Balance	16,988	27,031
Related Allowance	1,812	3,410
Average Recorded Investment	16,992	30,665
Interest Income Recognized	1,224	2,120
Commercial real estate — investor | Loans with no related allowance
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	589	6,144
Unpaid Principal Balance	732	6,478
Related Allowance	0	0
Average Recorded Investment	606	7,092
Interest Income Recognized	0	0
Real estate construction
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	689	509
Unpaid Principal Balance	804	648
Related Allowance	75	84
Average Recorded Investment	709	529
Interest Income Recognized	22	31
Real estate construction | Loans with a related allowance
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	476	509
Unpaid Principal Balance	586	648
Related Allowance	75	84
Average Recorded Investment	489	529
Interest Income Recognized	22	31
Real estate construction | Loans with no related allowance
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	213	0
Unpaid Principal Balance	218	0
Related Allowance	0	0
Average Recorded Investment	220	0
Interest Income Recognized	0	0
Commercial real estate lending
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	18,252	33,417
Unpaid Principal Balance	18,524	34,157
Related Allowance	1,887	3,494
Average Recorded Investment	18,307	38,286
Interest Income Recognized	1,246	2,151
Commercial real estate lending | Loans with a related allowance
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	17,450	27,273
Unpaid Principal Balance	17,574	27,679
Related Allowance	1,887	3,494
Average Recorded Investment	17,481	31,194
Interest Income Recognized	1,246	2,151
Commercial real estate lending | Loans with no related allowance
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	802	6,144
Unpaid Principal Balance	950	6,478
Related Allowance	0	0
Average Recorded Investment	826	7,092
Interest Income Recognized	0	0
Total commercial
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	191,406	260,671
Unpaid Principal Balance	210,437	289,029
Related Allowance	14,976	24,564
Average Recorded Investment	213,835	275,673
Interest Income Recognized	3,415	6,416
Total commercial | Loans with a related allowance
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	96,931	132,603
Unpaid Principal Balance	102,291	138,422
Related Allowance	14,976	24,564
Average Recorded Investment	105,595	141,842
Interest Income Recognized	2,488	4,759
Total commercial | Loans with no related allowance
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	94,475	128,068
Unpaid Principal Balance	108,146	150,607
Related Allowance	0	0
Average Recorded Investment	108,240	133,831
Interest Income Recognized	927	1,657
Residential mortgage
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	49,153	43,876
Unpaid Principal Balance	52,102	46,977
Related Allowance	6,893	6,438
Average Recorded Investment	49,582	45,218
Interest Income Recognized	1,363	1,735
Residential mortgage | Loans with a related allowance
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	42,684	37,902
Unpaid Principal Balance	45,028	39,979
Related Allowance	6,893	6,438
Average Recorded Investment	43,090	38,608
Interest Income Recognized	1,258	1,551
Residential mortgage | Loans with no related allowance
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	6,469	5,974
Unpaid Principal Balance	7,074	6,998
Related Allowance	0	0
Average Recorded Investment	6,492	6,610
Interest Income Recognized	105	184
Home equity
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	10,891	11,176
Unpaid Principal Balance	11,826	12,016
Related Allowance	3,684	3,943
Average Recorded Investment	11,077	11,527
Interest Income Recognized	411	631
Home equity | Loans with a related allowance
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	10,351	11,070
Unpaid Principal Balance	11,283	11,909
Related Allowance	3,684	3,943
Average Recorded Investment	10,537	11,420
Interest Income Recognized	411	627
Home equity | Loans with no related allowance
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	540	106
Unpaid Principal Balance	543	107
Related Allowance	0	0
Average Recorded Investment	540	107
Interest Income Recognized	0	4
Other consumer
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	1,092	1,012
Unpaid Principal Balance	1,093	1,023
Related Allowance	118	109
Average Recorded Investment	1,095	1,021
Interest Income Recognized	1	2
Other consumer | Loans with a related allowance
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	1,092	1,012
Unpaid Principal Balance	1,093	1,023
Related Allowance	118	109
Average Recorded Investment	1,095	1,021
Interest Income Recognized	1	2
Other consumer | Loans with no related allowance
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	0	0
Unpaid Principal Balance	0	0
Related Allowance	0	0
Average Recorded Investment	0	0
Interest Income Recognized	0	0
Total consumer
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	61,136	56,064
Unpaid Principal Balance	65,021	60,016
Related Allowance	10,695	10,490
Average Recorded Investment	61,754	57,766
Interest Income Recognized	1,775	2,368
Total consumer | Loans with a related allowance
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	54,127	49,984
Unpaid Principal Balance	57,404	52,911
Related Allowance	10,695	10,490
Average Recorded Investment	54,722	51,049
Interest Income Recognized	1,670	2,180
Total consumer | Loans with no related allowance
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	7,009	6,080
Unpaid Principal Balance	7,617	7,105
Related Allowance	0	0
Average Recorded Investment	7,032	6,717
Interest Income Recognized	$ 105	$ 188

Loans (Details Textuals)

Loans (Details Textuals) $ in Thousands	9 Months Ended
	Sep. 30, 2017USD ($)	Sep. 30, 2016USD ($)	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans	$ 20,931,460		$ 20,054,716
Allowance for loan losses	276,551		278,335	$ 274,264
Financing Receivable, Modifications, Post-Modification Recorded Investment	17,476	$ 9,038
Restructured Loans Subsequently Accruing	6,000
Ytd Restructured Loans Still On Nonaccrual	$ 11,000
Oil and Gas Portfolio Segment
Financing Receivable, Allowance for Credit Losses [Line Items]
Number of contracts	56
Loans	$ 577,000		668,000
Allowance for loan losses	$ 30,000		$ 38,000	$ 42,000
Percent of loans	5.20%

Loans, Troubled Debt Restructur

Loans, Troubled Debt Restructurings Performing and Nonaccrual (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Financing Receivable, Modifications [Line Items]
Performing Restructured Loans	$ 77,178	$ 79,857
Nonaccrual Restructured Loans	33,520	29,385
Commercial and industrial
Financing Receivable, Modifications [Line Items]
Performing Restructured Loans	32,572	31,884
Nonaccrual Restructured Loans	7,994	1,276
Commercial real estate — owner occupied
Financing Receivable, Modifications [Line Items]
Performing Restructured Loans	4,077	5,490
Nonaccrual Restructured Loans	2,145	2,220
Commercial real estate — investor
Financing Receivable, Modifications [Line Items]
Performing Restructured Loans	14,294	15,289
Nonaccrual Restructured Loans	589	924
Real estate construction
Financing Receivable, Modifications [Line Items]
Performing Restructured Loans	316	359
Nonaccrual Restructured Loans	160	150
Residential mortgage
Financing Receivable, Modifications [Line Items]
Performing Restructured Loans	16,859	18,100
Nonaccrual Restructured Loans	20,248	21,906
Home equity
Financing Receivable, Modifications [Line Items]
Performing Restructured Loans	7,987	7,756
Nonaccrual Restructured Loans	2,364	2,877
Other consumer
Financing Receivable, Modifications [Line Items]
Performing Restructured Loans	1,073	979
Nonaccrual Restructured Loans	$ 20	$ 32

Loans, Loans Modified in a Trou

Loans, Loans Modified in a Troubled Debt Restructuring (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2017USD ($)loan	Sep. 30, 2016USD ($)loan
Financing Receivable, Modifications [Line Items]
Number of Loans | loan	104	116
Recorded Investment	$ 17,476	$ 9,038
Unpaid Principal Balance	$ 22,428	$ 9,463
Commercial and industrial
Financing Receivable, Modifications [Line Items]
Number of Loans | loan	19	10
Recorded Investment	$ 11,387	$ 2,455
Unpaid Principal Balance	$ 15,898	$ 2,517
Commercial real estate — owner occupied
Financing Receivable, Modifications [Line Items]
Number of Loans | loan	2	1
Recorded Investment	$ 710	$ 117
Unpaid Principal Balance	$ 710	$ 124
Real estate construction
Financing Receivable, Modifications [Line Items]
Number of Loans | loan	0	1
Recorded Investment	$ 0	$ 66
Unpaid Principal Balance	$ 0	$ 91
Residential mortgage
Financing Receivable, Modifications [Line Items]
Number of Loans | loan	48	56
Recorded Investment	$ 4,445	$ 4,676
Unpaid Principal Balance	$ 4,638	$ 4,922
Home equity
Financing Receivable, Modifications [Line Items]
Number of Loans | loan	35	47
Recorded Investment	$ 934	$ 1,709
Unpaid Principal Balance	$ 1,182	$ 1,793
Other consumer
Financing Receivable, Modifications [Line Items]
Number of Loans | loan	0	1
Recorded Investment	$ 0	$ 15
Unpaid Principal Balance	$ 0	$ 16

Loans, Troubled Debt Restruct58

Loans, Troubled Debt Restructurings Subsequent Default (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2017USD ($)loan	Sep. 30, 2016USD ($)loan
Financing Receivable, Modifications [Line Items]
Number of Loans | loan	36	49
Recorded Investment | $	$ 1,707	$ 3,507
Commercial and industrial
Financing Receivable, Modifications [Line Items]
Number of Loans | loan	1	0
Recorded Investment | $	$ 1	$ 0
Residential mortgage
Financing Receivable, Modifications [Line Items]
Number of Loans | loan	21	36
Recorded Investment | $	$ 1,335	$ 3,310
Home equity
Financing Receivable, Modifications [Line Items]
Number of Loans | loan	14	12
Recorded Investment | $	$ 371	$ 182
Other consumer
Financing Receivable, Modifications [Line Items]
Number of Loans | loan	0	1
Recorded Investment | $	$ 0	$ 15

Loans, Changes in the Allowance

Loans, Changes in the Allowance for Loan Losses by Portfolio Segment (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2017	Dec. 31, 2016	Sep. 30, 2017	Dec. 31, 2016
Changes in the allowance for loan losses by portfolio segment
Balance at beginning of period	$ 278,335	$ 274,264
Charge offs	(41,957)	(86,439)
Recoveries	13,173	21,510
Net Charge offs	(28,784)	(64,929)
Provision for loan losses	27,000	69,000
Balance at end of period	276,551	278,335
Allowance for loan losses:
Individually evaluated			$ 25,671	$ 35,054
Collectively evaluated			250,880	243,281
Total allowance for loan losses	276,551	278,335	276,551	278,335
Loans:
Individually evaluated			252,542	316,735
Collectively evaluated			20,678,918	19,737,981
Total loans			20,931,460	20,054,716
Commercial and industrial
Changes in the allowance for loan losses by portfolio segment
Balance at beginning of period	140,126	129,959
Charge offs	(33,928)	(71,016)
Recoveries	9,072	14,543
Net Charge offs	(24,856)	(56,473)
Provision for loan losses	23,587	66,640
Balance at end of period	138,857	140,126
Allowance for loan losses:
Individually evaluated			11,540	21,047
Collectively evaluated			127,317	119,079
Total allowance for loan losses	138,857	129,959	138,857	140,126
Loans:
Individually evaluated			154,028	213,271
Collectively evaluated			6,380,632	6,275,743
Total loans			6,534,660	6,489,014
Commercial real estate — owner occupied
Changes in the allowance for loan losses by portfolio segment
Balance at beginning of period	14,034	18,680
Charge offs	(83)	(512)
Recoveries	158	74
Net Charge offs	75	(438)
Provision for loan losses	(4,352)	(4,208)
Balance at end of period	9,757	14,034
Allowance for loan losses:
Individually evaluated			1,549	23
Collectively evaluated			8,208	14,011
Total allowance for loan losses	9,757	18,680	9,757	14,034
Loans:
Individually evaluated			19,126	13,983
Collectively evaluated			807,938	883,741
Total loans			827,064	897,724
Commercial real estate — investor
Changes in the allowance for loan losses by portfolio segment
Balance at beginning of period	45,285	43,018
Charge offs	(803)	(1,504)
Recoveries	218	1,624
Net Charge offs	(585)	120
Provision for loan losses	1,798	2,147
Balance at end of period	46,498	45,285
Allowance for loan losses:
Individually evaluated			1,812	3,410
Collectively evaluated			44,686	41,875
Total allowance for loan losses	45,285	45,285	46,498	45,285
Loans:
Individually evaluated			17,563	32,908
Collectively evaluated			3,327,973	3,541,824
Total loans			3,345,536	3,574,732
Real estate construction
Changes in the allowance for loan losses by portfolio segment
Balance at beginning of period	26,932	25,266
Charge offs	(225)	(558)
Recoveries	60	203
Net Charge offs	(165)	(355)
Provision for loan losses	(1,340)	2,021
Balance at end of period	25,427	26,932
Allowance for loan losses:
Individually evaluated			75	84
Collectively evaluated			25,352	26,848
Total allowance for loan losses	25,427	25,266	25,427	26,932
Loans:
Individually evaluated			689	509
Collectively evaluated			1,551,446	1,431,988
Total loans			1,552,135	1,432,497
Residential mortgage
Changes in the allowance for loan losses by portfolio segment
Balance at beginning of period	27,046	28,261
Charge offs	(1,472)	(4,332)
Recoveries	754	755
Net Charge offs	(718)	(3,577)
Provision for loan losses	4,632	2,362
Balance at end of period	30,960	27,046
Allowance for loan losses:
Individually evaluated			6,893	6,438
Collectively evaluated			24,067	20,608
Total allowance for loan losses	27,046	27,046	30,960	27,046
Loans:
Individually evaluated			49,153	43,876
Collectively evaluated			7,359,318	6,288,451
Total loans			7,408,471	6,332,327
Home equity
Changes in the allowance for loan losses by portfolio segment
Balance at beginning of period	20,364	23,555
Charge offs	(2,208)	(4,686)
Recoveries	2,348	3,491
Net Charge offs	140	(1,195)
Provision for loan losses	(479)	(1,996)
Balance at end of period	20,025	20,364
Allowance for loan losses:
Individually evaluated			3,684	3,943
Collectively evaluated			16,341	16,421
Total allowance for loan losses	20,025	23,555	20,025	20,364
Loans:
Individually evaluated			10,891	11,176
Collectively evaluated			879,239	923,267
Total loans			890,130	934,443
Other consumer
Changes in the allowance for loan losses by portfolio segment
Balance at beginning of period	4,548	5,525
Charge offs	(3,238)	(3,831)
Recoveries	563	820
Net Charge offs	(2,675)	(3,011)
Provision for loan losses	3,154	2,034
Balance at end of period	5,027	4,548
Allowance for loan losses:
Individually evaluated			118	109
Collectively evaluated			4,909	4,439
Total allowance for loan losses	$ 5,027	$ 5,525	5,027	4,548
Loans:
Individually evaluated			1,092	1,012
Collectively evaluated			372,372	392,967
Total loans			$ 373,464	$ 393,979

Loans Loans, Changes in the All

Loans Loans, Changes in the Allowance for Loan Losses by Oil and Gas Segment (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2017	Dec. 31, 2016	Sep. 30, 2017	Dec. 31, 2016
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance at beginning of period	$ 278,335	$ 274,264
Charge offs	(41,957)	(86,439)
Recoveries	13,173	21,510
Net Charge offs	(28,784)	(64,929)
Provision for loan losses	27,000	69,000
Balance at end of period	276,551	278,335
Allowance for loan losses
Individually evaluated			$ 25,671	$ 35,054
Collectively evaluated			250,880	243,281
Total allowance for loan losses	276,551	278,335	276,551	278,335
Loans
Individually evaluated			252,542	316,735
Collectively evaluated			20,678,918	19,737,981
Total loans			20,931,460	20,054,716
Oil and Gas Portfolio Segment
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance at beginning of period	38,000	42,000
Charge offs	(26,000)	(59,000)
Recoveries	0	0
Net Charge offs	(26,000)	(59,000)
Provision for loan losses	18,000	55,000
Balance at end of period	30,000	38,000
Allowance for loan losses
Individually evaluated			2,000	14,000
Collectively evaluated			28,000	24,000
Total allowance for loan losses	$ 30,000	$ 42,000	30,000	38,000
Loans
Individually evaluated			92,000	147,000
Collectively evaluated			485,000	521,000
Total loans			$ 577,000	$ 668,000

Loans, Changes in the Allowan61

Loans, Changes in the Allowance for Loan Losses (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2017	Dec. 31, 2016
Change in the allowance for unfunded commitments
Balance at beginning of period	$ 25,000
Balance at end of period	24,000	$ 25,000
Allowance for Unfunded Commitments:
Change in the allowance for unfunded commitments
Balance at beginning of period	25,400	24,400
Provision for unfunded commitments	(1,000)	1,000
Balance at end of period	$ 24,400	$ 25,400

Goodwill and Other Intangible62

Goodwill and Other Intangible Assets, Summary of Core Deposit and Other Intangibles (Details) - USD ($)	3 Months Ended				9 Months Ended		12 Months Ended
	Sep. 30, 2017	Mar. 31, 2017	Sep. 30, 2016	Mar. 31, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Summary of core deposit intangibles and other intangibles
Additions during the period		$ 162,000		$ 1,000,000
Amortization of other intangible assets	$ 450,000		$ 525,000		$ 1,459,000	$ 1,568,000
Core Deposit Intangibles
Summary of core deposit intangibles and other intangibles
Gross carrying amount	4,385,000				4,385,000		$ 4,385,000
Accumulated amortization	(4,385,000)				(4,385,000)		(4,273,000)
Total Estimated Amortization Expense	0				0		112,000
Amortization of other intangible assets					112,000		281,000
Other Intangible Assets
Summary of core deposit intangibles and other intangibles
Gross carrying amount	32,572,000				32,572,000		32,410,000
Accumulated amortization	(18,492,000)				(18,492,000)		(17,145,000)
Total Estimated Amortization Expense	$ 14,080,000				14,080,000		15,265,000
Additions during the period					162,000		1,012,000
Amortization of other intangible assets					$ 1,347,000		$ 1,812,000

Goodwill and Other Intangible63

Goodwill and Other Intangible Assets, Mortgage Servicing Rights Roll-Forward (Details) - USD ($) $ in Thousands		9 Months Ended	12 Months Ended
		Sep. 30, 2017	Dec. 31, 2016
Mortgage servicing rights:
Mortgage servicing rights at beginning of period		$ 62,085	$ 62,150
Additions		4,822	12,262
Amortization		(7,635)	(12,327)
Mortgage servicing rights at end of period		59,272	62,085
Valuation Allowance for Impairment of Recognized Servicing Assets [Roll Forward]
Valuation allowance at beginning of period		(609)	(809)
(Additions) recoveries, net		(286)	200
Valuation allowance at end of period		(895)	(609)
Mortgage servicing rights, net		58,377	61,476
Fair value of mortgage servicing rights		62,625	73,149
Portfolio of residential mortgage loans serviced for others (“servicing portfolio”)		$ 7,653,458	$ 7,974,742
Mortgage servicing rights, net to servicing portfolio		0.76%	0.77%
Mortgage servicing rights expense	[1]	$ 7,921	$ 12,127
[1]	(a) Includes the amortization of mortgage servicing rights and additions / recoveries to the valuation allowance of mortgage servicing rights, and is a component of mortgage banking, net in the consolidated statements of income.

Goodwill and Other Intangible64

Goodwill and Other Intangible Assets, Estimated Future Amortization Expense (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Core Deposit Intangibles
Estimated future amortization expense
Total Estimated Amortization Expense	$ 0	$ 112
Other Intangible Assets
Estimated future amortization expense
Three Months Ended December 31, 2017	451
Year ending December 31, 2018	1,771
Year ending December 31, 2019	1,472
Year ending December 31, 2020	1,355
Year ending December 31, 2021	1,331
Year ending December 31, 2022	1,308
Beyond 2,022	6,392
Total Estimated Amortization Expense	14,080	$ 15,265
Mortgage Servicing Rights
Estimated future amortization expense
Three Months Ended December 31, 2017	2,593
Year ending December 31, 2018	9,337
Year ending December 31, 2019	7,792
Year ending December 31, 2020	6,522
Year ending December 31, 2021	5,484
Year ending December 31, 2022	4,641
Beyond 2,022	22,903
Total Estimated Amortization Expense	$ 59,272

Goodwill and Other Intangible65

Goodwill and Other Intangible Assets (Details Textuals)	3 Months Ended		9 Months Ended	12 Months Ended
	Mar. 31, 2017USD ($)acquisition	Mar. 31, 2016USD ($)acquisition	Sep. 30, 2017USD ($)	Dec. 31, 2016USD ($)
Business Acquisition [Line Items]
Goodwill acquired during period	$ 55,000	$ 3,000,000
Additions to finite-lived intangible assets	$ 162,000	$ 1,000,000
Number of acquisitions | acquisition	1	2
Goodwill			$ 972,006,000	$ 971,951,000
Goodwill, Impairment Loss			$ 0	$ 0

Short and Long-Term Funding (Co

Short and Long-Term Funding (Components of Short-term and Long-term Funding) (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Short-term Funding [Abstract]
Federal funds purchased	$ 220,575	$ 208,150
Securities sold under agreements to repurchase	255,975	300,197
Federal funds purchased and securities sold under agreements to repurchase	476,550	508,347
FHLB advances	520,000	482,000
Commercial paper	68,067	101,688
Other short-term funding	588,067	583,688
Total short-term funding	1,064,617	1,092,035
Long-term Funding
FHLB advances	2,650,172	2,265,188
Senior notes, at par	250,000	250,000
Subordinated notes, at par	250,000	250,000
Other long-term funding and capitalized costs	(2,887)	(3,393)
Total long-term funding	3,147,285	2,761,795
Total short and long-term funding	$ 4,211,902	$ 3,853,830

Short and Long-Term Funding (Re

Short and Long-Term Funding (Remaining Contractual Maturity of the Securities Sold Under Agreements to Repurchase) (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
RemainingContractualMaturityoftheSecuritiesSoldUnderAgreementtoRepurchase [Line Items]
Repurchase agreements	$ 255,975	$ 300,197
Overnight and Continuous
RemainingContractualMaturityoftheSecuritiesSoldUnderAgreementtoRepurchase [Line Items]
Repurchase agreements	255,975	300,197
Up to 30 days
RemainingContractualMaturityoftheSecuritiesSoldUnderAgreementtoRepurchase [Line Items]
Repurchase agreements	0	0
30-90 days
RemainingContractualMaturityoftheSecuritiesSoldUnderAgreementtoRepurchase [Line Items]
Repurchase agreements	0	0
Greater than 90 days
RemainingContractualMaturityoftheSecuritiesSoldUnderAgreementtoRepurchase [Line Items]
Repurchase agreements	0	0
Agency mortgage-related securities
RemainingContractualMaturityoftheSecuritiesSoldUnderAgreementtoRepurchase [Line Items]
Repurchase agreements	255,975	300,197
Agency mortgage-related securities | Overnight and Continuous
RemainingContractualMaturityoftheSecuritiesSoldUnderAgreementtoRepurchase [Line Items]
Repurchase agreements	255,975	300,197
Agency mortgage-related securities | Up to 30 days
RemainingContractualMaturityoftheSecuritiesSoldUnderAgreementtoRepurchase [Line Items]
Repurchase agreements	0	0
Agency mortgage-related securities | 30-90 days
RemainingContractualMaturityoftheSecuritiesSoldUnderAgreementtoRepurchase [Line Items]
Repurchase agreements	0	0
Agency mortgage-related securities | Greater than 90 days
RemainingContractualMaturityoftheSecuritiesSoldUnderAgreementtoRepurchase [Line Items]
Repurchase agreements	$ 0	$ 0

Short and Long-Term Funding (Lo

Short and Long-Term Funding (Long-term Funding Narrative) (Details) - USD ($) $ in Millions	1 Months Ended
	Nov. 30, 2014	Sep. 30, 2017	Dec. 31, 2016
Subordinated Borrowing [Line Items]
Carrying Value of Securities Purchased under Agreements to Resell and Deposits Paid for Securities Borrowed		$ 391
Federal Home Loan Bank, Advances, Weighted Average Interest Rate		1.02%	0.50%
Two Thousand Fourteen Senior Notes
Subordinated Borrowing [Line Items]
New Senior Debt Issued	$ 250
Debt Instrument, Interest Rate, Stated Percentage	2.75%
Two Thousand Fourteen Subordinated Notes
Subordinated Borrowing [Line Items]
Junior Subordinated Debentures Issued	$ 250
Debt Instrument, Term	10 years
Subordinated Borrowing, Interest Rate	4.25%

Derivative and Hedging Activi69

Derivative and Hedging Activities, Derivative Instruments Not Designated as Hedging Instruments (Details) - Not Designated as Hedging Instrument - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Trading assets | Interest rate-related instruments — customer and mirror
Derivative Instruments Not Designated as Hedging Instruments [Abstract]
Notional Amount	$ 2,198,794	$ 2,039,323
Fair Value	26,837	33,671
Trading assets | Foreign currency exchange forwards
Derivative Instruments Not Designated as Hedging Instruments [Abstract]
Notional Amount	130,191	109,675
Fair Value	3,053	2,002
Trading assets | Commodity contracts
Derivative Instruments Not Designated as Hedging Instruments [Abstract]
Notional Amount	424,996	127,582
Fair Value	18,539	16,725
Trading liabilities | Interest rate-related instruments — customer and mirror
Derivative Instruments Not Designated as Hedging Instruments [Abstract]
Notional Amount	2,198,794	2,039,323
Fair Value	(26,469)	(33,188)
Trading liabilities | Foreign currency exchange forwards
Derivative Instruments Not Designated as Hedging Instruments [Abstract]
Notional Amount	122,307	106,251
Fair Value	(3,033)	(1,943)
Trading liabilities | Commodity contracts
Derivative Instruments Not Designated as Hedging Instruments [Abstract]
Notional Amount	396,754	128,368
Fair Value	(17,310)	(15,972)
Other assets | Interest rate lock commitments (mortgage)
Derivative Instruments Not Designated as Hedging Instruments [Abstract]
Notional Amount	354,075	285,345
Fair Value	2,729	206
Other assets | Forward commitments (mortgage)
Derivative Instruments Not Designated as Hedging Instruments [Abstract]
Notional Amount	243,500	179,600
Fair Value	234	2,908
Other assets | Purchased options (time deposit)
Derivative Instruments Not Designated as Hedging Instruments [Abstract]
Notional Amount	53,074	80,554
Fair Value	1,434	2,576
Other liabilities | Written options (time deposit)
Derivative Instruments Not Designated as Hedging Instruments [Abstract]
Notional Amount	53,074	80,554
Fair Value	$ (1,434)	$ (2,576)

Derivative and Hedging Activi70

Derivative and Hedging Activities, Income Statement Category of the Gains and Losses (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Capital market fees, net | Interest rate-related instruments — customer and mirror
Gain (loss) on derivative instruments not designated as hedging instruments
Gain / (Loss) Recognized in Income	$ (115)	$ (888)
Capital market fees, net | Foreign currency exchange forwards
Gain (loss) on derivative instruments not designated as hedging instruments
Gain / (Loss) Recognized in Income	(39)	(85)
Capital market fees, net | Commodity contracts
Gain (loss) on derivative instruments not designated as hedging instruments
Gain / (Loss) Recognized in Income	476	690
Mortgage banking, net | Interest rate lock commitments (mortgage)
Gain (loss) on derivative instruments not designated as hedging instruments
Gain / (Loss) Recognized in Income	2,523	2,768
Mortgage banking, net | Forward commitments (mortgage)
Gain (loss) on derivative instruments not designated as hedging instruments
Gain / (Loss) Recognized in Income	$ (2,674)	$ (2,271)

Derivative and Hedging Activi71

Derivative and Hedging Activities (Details Textuals) - USD ($) $ in Millions	Sep. 30, 2017	Dec. 31, 2016
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Investment securities and cash equivalents pledged as collateral	$ 26	$ 40
Derivative collateral right to reclaim cash	$ 3	$ 0

Balance Sheet Offsetting (Detai

Balance Sheet Offsetting (Details) - Interest and commodity agreements - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	$ 23,224	$ 18,031
Gross amounts offset in the balance sheet	0	0
Net amounts presented in the balance sheet	23,224	18,031
Financial instruments	(21,783)	(18,031)
Collateral	(1,441)	0
Net amount	0	0
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	21,783	31,075
Gross amounts offset in the balance sheet	0	0
Net amounts presented in the balance sheet	21,783	31,075
Financial instruments	(21,783)	(18,031)
Collateral	0	(11,148)
Net amount	$ 0	$ 1,896

Commitments, Off-Balance Shee73

Commitments, Off-Balance Sheet Arrangements, Legal Proceedings and Regulatory Matters, Summary of Lending Related and Other Commitments (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Schedule of lending-related and other commitments [Line Items]
Lending related commitments, fair value	$ 0	$ 0
Commitments to extend credit, excluding commitments to originate residential mortgage loans held for sale
Summary of lending-related and other commitments
Lending related commitments	8,002,766	8,131,131
Commercial Letters Of Credit
Summary of lending-related and other commitments
Lending related commitments	8,961	7,923
Standby Letters of Credit
Summary of lending-related and other commitments
Lending related commitments	233,783	259,632
Standby letters of credit, fair value	$ 2,000	$ 3,000

Commitments, Off-Balance Shee74

Commitments, Off-Balance Sheet Arrangements, Legal Proceedings and Regulatory Matters Residential Mortgage Repurchase Reserve (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2017	Dec. 31, 2016
Residential mortgage repurchase reserve
Balance at beginning of period	$ 25,000
Balance at end of period	24,000	$ 25,000
Mortgage Repurchase Reserve
Residential mortgage repurchase reserve
Balance at beginning of period	900	1,197
Repurchase provision expense	165	456
Adjustments to provision expense	0	(750)
Charge offs, net	(148)	(3)
Balance at end of period	$ 917	$ 900

Commitments, Off-Balance Shee75

Commitments, Off-Balance Sheet Arrangements, Legal Proceedings and Regulatory Matters (Details Textuals)	Jan. 11, 2016USD ($)complaint	May 22, 2015USD ($)branchloan_production_office	Sep. 30, 2017USD ($)	Sep. 06, 2017complaint	Aug. 30, 2017complaint	Jul. 28, 2017complaint	Dec. 31, 2016USD ($)
Commitments, Off-Balance Sheet Arrangements, and Contingent Liabilities (Textuals) [Line Items]
Unfunded commitments			$ 24,000,000				$ 25,000,000
Carrying value of investments			142,000,000				85,000,000
Commitments under unconsolidated projects			101,000,000				69,000,000
Number of complaints filed under legal proceedings | complaint	2
Commitment term		3 years
Mortgage loan commitment		$ 196,000,000
Number of branch opening commitments | branch		1
Number of loan production offices | loan_production_office		4
Conciliation agreement cost, commitment term		4 years
Loans repurchased under make whole requests			1,000,000				2,000,000
Loans sold to outside investors original amount			9,700,000,000
Loans sold to outside investors remaining outstanding amount			6,100,000,000
Residential mortgage loans sold with recourse risk			77,000,000				62,000,000
Residential mortgage loans sold with credit recourse risk			$ 79,000,000				$ 98,000,000
The Official Committee of Unsecured Creditors of World Marketing Chicago LLC v Associated Bank [Member]
Commitments, Off-Balance Sheet Arrangements, and Contingent Liabilities (Textuals) [Line Items]
Damages sought	$ 6,000,000
Damages sought, cash	4,000,000
American Funds Service Company v Associated Bank [Member]
Commitments, Off-Balance Sheet Arrangements, and Contingent Liabilities (Textuals) [Line Items]
Damages sought	$ 600,000
Schumel et al v. Bank Mutual Corporation et al, and Paquin et al v. Bank Mutual Corporation et al [Domain]
Commitments, Off-Balance Sheet Arrangements, and Contingent Liabilities (Textuals) [Line Items]
Number of complaints filed under legal proceedings | complaint						2
Wollenburg et al. v. Bank Mutual Corporation et al. [Member]
Commitments, Off-Balance Sheet Arrangements, and Contingent Liabilities (Textuals) [Line Items]
Number of complaints filed under legal proceedings | complaint					1
Parshall et al. v. Bank Mutual Corporation et al. [Member]
Commitments, Off-Balance Sheet Arrangements, and Contingent Liabilities (Textuals) [Line Items]
Number of complaints filed under legal proceedings | complaint				1

Fair Value Measurements, Assets

Fair Value Measurements, Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Investment securities available for sale:
Investment securities available for sale	$ 3,801,699	$ 4,680,226
Trading assets	48,429	52,398
Liabilities, Fair Value Disclosure [Abstract]
Trading liabilities	46,812	51,103
Fair Value, Inputs, Level 1
Investment securities available for sale:
Investment securities available for sale	2,651	2,602
Fair Value, Inputs, Level 2
Investment securities available for sale:
Investment securities available for sale	3,799,048	4,677,424
Trading assets	49,863	54,974
Liabilities, Fair Value Disclosure [Abstract]
Trading liabilities	48,246	53,679
Fair Value, Inputs, Level 3
Investment securities available for sale:
Investment securities available for sale	0	200
Trading assets	2,963	3,114
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 1 | US Treasury Securities
Investment securities available for sale:
Investment securities available for sale	1,001	1,000
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 1 | Other Debt And Other Equity Securities
Investment securities available for sale:
Investment securities available for sale	1,650	1,602
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 1 | Total investment securities available for sale
Investment securities available for sale:
Investment securities available for sale	2,651	2,602
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 2 | FNMA / FHLMC
Investment securities available for sale:
Investment securities available for sale	505,261	639,930
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 2 | GNMA
Investment securities available for sale:
Investment securities available for sale	1,667,836	2,004,475
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 2 | Private Label
Investment securities available for sale:
Investment securities available for sale	1,072	1,121
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 2 | GNMA Commercial Mortgage-Related Securities
Investment securities available for sale:
Investment securities available for sale	1,513,077	2,028,898
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 2 | Asset backed Securities
Investment securities available for sale:
Investment securities available for sale	108,628	0
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 2 | Other Debt And Other Equity Securities
Investment securities available for sale:
Investment securities available for sale	3,174	3,000
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 2 | Total investment securities available for sale
Investment securities available for sale:
Investment securities available for sale	3,799,048	4,677,424
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 2 | Residential Loans Held For Sale Member
Investment securities available for sale:
Trading assets	113,064	0
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 2 | Interest rate-related instruments — customer and mirror
Investment securities available for sale:
Trading assets	26,837	33,671
Liabilities, Fair Value Disclosure [Abstract]
Trading liabilities	26,469	33,188
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 2 | Foreign currency exchange forwards
Investment securities available for sale:
Trading assets	3,053	2,002
Liabilities, Fair Value Disclosure [Abstract]
Trading liabilities	3,033	1,943
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 2 | Commodity contracts
Investment securities available for sale:
Trading assets	18,539	16,725
Liabilities, Fair Value Disclosure [Abstract]
Trading liabilities	17,310	15,972
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 2 | Purchased options (time deposit)
Investment securities available for sale:
Trading assets	1,434	2,576
Liabilities, Fair Value Disclosure [Abstract]
Trading liabilities	1,434	2,576
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 3 | Other Debt And Other Equity Securities
Investment securities available for sale:
Investment securities available for sale	0	200
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 3 | Total investment securities available for sale
Investment securities available for sale:
Investment securities available for sale	0	200
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 3 | Interest rate lock commitments (mortgage)
Investment securities available for sale:
Trading assets	2,729	206
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 3 | Forward commitments (mortgage)
Investment securities available for sale:
Trading assets	$ 234	$ 2,908

Fair Value Measurements, Asse77

Fair Value Measurements, Assets and Liabilities Measured at Fair Value Using Significant Unobservable Inputs (Level 3) (Details) - USD ($) $ in Thousands		9 Months Ended	12 Months Ended
		Sep. 30, 2017	Dec. 31, 2016
Total investment securities available for sale
Assets and Liabilities Measured at Fair Value Using Significant Unobservable Inputs (Level 3)
Beginning Balance		$ 200	$ 200
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3	[1]	(200)
Ending Balance		0	200
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Mortgage derivative loss		0	0
Derivative Financial Instruments
Assets and Liabilities Measured at Fair Value Using Significant Unobservable Inputs (Level 3)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3	[1]	0
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Beginning Balance		3,114	1,361
Mortgage derivative loss		(151)	1,753
Ending Balance		$ 2,963	$ 3,114
[1]	(a) During the first quarter of 2017, the $200,000 level 3 investment security was transferred to level 2 based upon new pricing information.

Fair Value Measurements, Asse78

Fair Value Measurements, Assets and Liabilities Measured at Fair Value on a Nonrecurring Basis (Details) - USD ($) $ in Thousands	9 Months Ended		12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Assets and Liabilities Measured at Fair Value on a Non-recurring Basis
Mortgage servicing rights	$ 58,377		$ 61,476
Mortgage Servicing Rights (MSR) Impairment (Recovery)	286	$ 2,486
Fair Value, Inputs, Level 2
Assets and Liabilities Measured at Fair Value on a Non-recurring Basis
Commercial Loans Held-for-sale, Fair Value Disclosure	9,718		12,474
Residential Held-for-sale, Fair Value Disclosure	113,064		108,010
Fair Value, Measurements, Nonrecurring [Member] | Fair Value, Inputs, Level 2
Assets and Liabilities Measured at Fair Value on a Non-recurring Basis
Commercial Loans Held-for-sale, Fair Value Disclosure	9,718		12,474
Provision for Credit Losses, Commercial Loans held-for-sale	0		(559)
Residential Held-for-sale, Fair Value Disclosure			108,010
Mortgage banking, net			(3,760)
Other Real Estate Owned Fair Value Disclosure	3,291		9,752
Foreclosure / OREO expense, net	(939)		(1,091)
Fair Value, Measurements, Nonrecurring [Member] | Fair Value, Inputs, Level 3
Assets and Liabilities Measured at Fair Value on a Non-recurring Basis
Impaired loans	54,762		79,270
Provision for Credit Losses, Impaired Loans	(22,703)		(75,194)
Mortgage servicing rights	62,625		73,149
Mortgage Servicing Rights (MSR) Impairment (Recovery)	$ (286)		$ 200

Fair Value Measurements Fair Va

Fair Value Measurements Fair Value Unobservable Level 3 Measurements (Details) - Fair Value, Inputs, Level 3	9 Months Ended
	Sep. 30, 2017
Discounted Cash Flow | Servicing Contracts
Assumption for Fair Value as of Balance Sheet Date of Assets or Liabilities that relate to Transferor's Continuing Involvement [Line Items]
Assumption for Fair Value of Assets or Liabilities that relate to Transferor's Continuing Involvement, Discount Rate	11.00%
Assumption for Fair Value of Assets or Liabilities that relate to Transferor's Continuing Involvement, Prepayment Speed	12.00%
Appraisals/Discounted Cash Flow | Impaired Finance Receivable
Assumption for Fair Value as of Balance Sheet Date of Assets or Liabilities that relate to Transferor's Continuing Involvement [Line Items]
Assumption for Fair Value of Assets or Liabilities that relate to Transferor's Continuing Involvement, Discount Rate	16.00%

Fair Value Measurements, Fair V

Fair Value Measurements, Fair Value of Financial Instruments (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Financial assets
Cash and due from banks	$ 354,331	$ 446,558
Interest-bearing deposits in other financial institutions	109,596	149,175
Federal funds sold and securities purchased under agreements to resell	27,700	46,500
Investment securities held to maturity	2,233,579	1,273,536
Investment securities held to maturity, fair value	2,243,845	1,264,674
Investment securities available for sale	3,801,699	4,680,226
FHLB and Federal Reserve Bank stocks	172,446	140,001
Commercial loans held for sale	9,718	12,474
Loans, net	20,654,909	19,776,381
Derivatives (trading and other assets)	48,429	52,398
Financial liabilities
Short-term funding	1,064,617	1,092,035
Long-term funding	3,147,285	2,761,795
Derivatives (trading and other liabilities)	46,812	51,103
Letters of Credit Outstanding, Amount	234,000	260,000
Fair Value, Inputs, Level 1
Financial assets
Cash and due from banks	354,331	446,558
Cash and due from banks, Fair Value	354,331	446,558
Interest-bearing deposits in other financial institutions	109,596	149,175
Interest-bearing deposits in other financial institutions, fair value	109,596	149,175
Federal funds sold and securities purchased under agreements to resell	27,700	46,500
Federal funds sold and securities purchased under agreements to resell, fair value	27,700	46,500
Investment securities available for sale	2,651	2,602
Investment securities available for sale, fair value	2,651	2,602
Fair Value, Inputs, Level 2
Financial assets
Investment securities held to maturity	2,233,579	1,273,536
Investment securities held to maturity, fair value	2,243,845	1,264,674
Investment securities available for sale	3,799,048	4,677,424
Investment securities available for sale, fair value	3,799,048	4,677,424
FHLB and Federal Reserve Bank stocks	172,446	140,001
FHLB and Federal Reserve Bank stocks, fair value	172,446	140,001
Commercial loans held for sale	9,718	12,474
Commercial Loans Held-for-sale, Fair Value Disclosure	9,718	12,474
Residential Loans on Real Estate, Carrying Amount of Mortgages	113,064	108,010
Residential Held-for-sale, Fair Value Disclosure	113,064	108,010
Bank owned life insurance	589,093	585,290
Bank owned life insurance, fair value	589,093	585,290
Derivatives (trading and other assets)	49,863	54,974
Derivatives (trading and other assets), fair value	49,863	54,974
Financial liabilities
Brokered CDs and other time deposits	2,321,277	1,606,127
Brokered CDs and other time deposits, fair value	2,321,277	1,606,127
Short-term funding	1,064,617	1,092,035
Short-term funding, fair value	1,064,617	1,092,035
Long-term funding	3,147,285	2,761,795
Long-term funding, fair value	3,171,059	2,791,841
Standby letters of credit	2,346	2,566
Standby letters of credit, fair value	2,346	2,566
Derivatives (trading and other liabilities)	48,246	53,679
Derivatives (trading and other liabilities), fair value	48,246	53,679
Fair Value, Inputs, Level 3
Financial assets
Investment securities available for sale	0	200
Investment securities available for sale, fair value	0	200
Loans, net	20,654,909	19,776,381
Loans, net, fair value	20,504,971	19,680,317
Derivatives (trading and other assets)	2,963	3,114
Derivatives (trading and other assets), fair value	2,963	3,114
Financial liabilities
Noninterest-bearing demand, savings, interest-bearing demand, and money market accounts	20,012,174	20,282,321
Noninterest-bearing demand, savings, interest-bearing demand, and money market deposits, fair value	$ 20,012,174	$ 20,282,321

Fair Value Measurements (Detail

Fair Value Measurements (Details Textuals)	9 Months Ended
	Sep. 30, 2017
Fair Value of Assets and Liabilities [Line Items]
Closing ratio	87.00%

Retirement Plans, Components of

Retirement Plans, Components of Net Periodic Benefit Cost for the Pension and Postretirement Tables (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
RAP
Net period benefit cost for the pension and postretirement plans
Service cost	$ 1,713	$ 1,636	$ 5,276	$ 5,086
Interest cost	1,795	1,781	5,307	5,341
Expected return on plan assets	(4,929)	(5,085)	(14,692)	(15,215)
Amortization of prior service cost	(19)	(80)	(56)	(55)
Amortization of actuarial loss	619	621	1,594	1,586
Total net pension and periodic benefit cost	(821)	(1,127)	(2,571)	(3,257)
Postretirement Plan
Net period benefit cost for the pension and postretirement plans
Interest cost	26	35	74	107
Amortization of prior service cost	(19)	0	(57)	0
Amortization of actuarial loss	2	0	2	0
Total net pension and periodic benefit cost	$ 9	$ 35	$ 19	$ 107

Retirement Plans (Details Textu

Retirement Plans (Details Textuals) (Details) $ in Millions	9 Months Ended
	Sep. 30, 2017USD ($)
RAP
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Contributions by Employer	$ 6

Segment Reporting (Details)

Segment Reporting (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Segment Income Statement Data Abstract
Net interest income	$ 190,122	$ 178,534	$ 554,215	$ 527,238
Noninterest income	85,895	95,234	248,136	260,594
Total revenue	276,017	273,768	802,351	787,832
Credit provision	5,000	21,000	26,000	55,000
Noninterest expense	177,427	175,314	527,434	523,645
Income (loss) before income taxes	93,590	77,454	248,917	209,187
Income tax expense (benefit)	28,589	23,638	69,663	63,746
Net income	$ 65,001	$ 53,816	$ 179,254	$ 145,441
Return on average allocated capital (ROCET1)	11.70%	10.50%	11.00%	9.70%
Segment Balance Sheet Data
Average earning assets	$ 27,459,795	$ 26,434,163	$ 26,851,992	$ 25,893,509
Average loans	20,899,137	20,052,776	20,500,978	19,541,072
Average deposits	22,441,445	21,404,025	21,813,679	20,758,415
Average allocated capital (CET1)	2,119,675	1,952,616	2,093,962	1,920,895
Operating Segments | Corporate and Commercial Specialty
Segment Income Statement Data Abstract
Net interest income	92,356	83,567	271,615	242,800
Noninterest income	12,278	12,623	36,768	35,172
Total revenue	104,634	96,190	308,383	277,972
Credit provision	9,499	11,080	32,549	38,933
Noninterest expense	39,681	37,968	116,578	109,511
Income (loss) before income taxes	55,454	47,142	159,256	129,528
Income tax expense (benefit)	19,070	14,907	53,082	42,623
Net income	$ 36,384	$ 32,235	$ 106,174	$ 86,905
Return on average allocated capital (ROCET1)	12.80%	11.70%	12.70%	10.90%
Segment Balance Sheet Data
Average earning assets	$ 10,923,762	$ 10,441,454	$ 10,846,418	$ 10,097,995
Average loans	10,916,829	10,435,341	10,837,933	10,088,777
Average deposits	7,398,970	6,227,305	6,759,105	5,906,695
Average allocated capital (CET1)	1,125,181	1,091,624	1,121,800	1,063,598
Operating Segments | Community, Consumer, and Business
Segment Income Statement Data Abstract
Net interest income	90,952	87,274	270,011	257,848
Noninterest income	67,867	78,580	198,546	207,460
Total revenue	158,819	165,854	468,557	465,308
Credit provision	5,046	5,969	15,317	18,357
Noninterest expense	120,241	127,454	361,580	370,714
Income (loss) before income taxes	33,532	32,431	91,660	76,237
Income tax expense (benefit)	11,736	11,351	32,081	26,683
Net income	$ 21,796	$ 21,080	$ 59,579	$ 49,554
Return on average allocated capital (ROCET1)	14.70%	13.20%	13.60%	10.50%
Segment Balance Sheet Data
Average earning assets	$ 9,608,242	$ 9,414,718	$ 9,418,173	$ 9,287,158
Average loans	9,602,098	9,413,401	9,414,880	9,285,848
Average deposits	11,788,606	11,526,639	11,568,220	11,320,106
Average allocated capital (CET1)	588,841	633,392	584,774	631,484
Operating Segments | Risk Management and Shared Services
Segment Income Statement Data Abstract
Net interest income	6,814	7,693	12,589	26,590
Noninterest income	5,750	4,031	12,822	17,962
Total revenue	12,564	11,724	25,411	44,552
Credit provision	(9,545)	3,951	(21,866)	(2,290)
Noninterest expense	17,505	9,892	49,276	43,420
Income (loss) before income taxes	4,604	(2,119)	(1,999)	3,422
Income tax expense (benefit)	(2,217)	(2,620)	(15,500)	(5,560)
Net income	$ 6,821	$ 501	$ 13,501	$ 8,982
Return on average allocated capital (ROCET1)	4.40%	(2.90%)	2.20%	1.40%
Segment Balance Sheet Data
Average earning assets	$ 6,927,791	$ 6,577,991	$ 6,587,401	$ 6,508,356
Average loans	380,210	204,034	248,165	166,447
Average deposits	3,253,869	3,650,081	3,486,354	3,531,614
Average allocated capital (CET1)	$ 405,653	$ 227,600	$ 387,388	$ 225,813

Accumulated Other Comprehensi85

Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance			$ (54,679)
Personnel expense	$ (105,852)	$ (103,819)	(314,954)	$ (307,346)
Interest income (amortization of net unrealized losses (gains) on available for sale securities transferred to held to maturity securities)	76	(1,441)	(2,499)	(4,465)
Total other comprehensive income (loss)	(818)	(14,707)	391	31,362
Ending Balance	(54,288)		(54,288)
Investment Securities Available For Sale
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	(19,428)	45,916	(20,079)	459
Other comprehensive income (loss) before reclassifications	(1,986)	(22,894)	1,646	59,849
Investment securities gain, net		13		(6,201)
Personnel expense	0	0	0	0
Interest income (amortization of net unrealized losses (gains) on available for sale securities transferred to held to maturity securities)	76	(1,441)	(2,499)	(4,465)
Income tax (expense) benefit	734	9,280	328	(18,768)
Total other comprehensive income (loss)	(1,176)	(15,042)	(525)	30,415
Ending Balance	(20,604)	30,874	(20,604)	30,874
Defined Benefit Pension and Post Retirement Obligations
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	(34,042)	(32,463)	(34,600)	(33,075)
Other comprehensive income (loss) before reclassifications	0	0	0	0
Investment securities gain, net		0		0
Personnel expense	583	541	1,483	1,531
Interest income (amortization of net unrealized losses (gains) on available for sale securities transferred to held to maturity securities)	0	0	0	0
Income tax (expense) benefit	(225)	(206)	(567)	(584)
Total other comprehensive income (loss)	358	335	916	947
Ending Balance	(33,684)	(32,128)	(33,684)	(32,128)
Accumulated Other Comprehensive Income (Loss)
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	(53,470)	13,453	(54,679)	(32,616)
Other comprehensive income (loss) before reclassifications	(1,986)	(22,894)	1,646	59,849
Investment securities gain, net		13		(6,201)
Personnel expense	583	541	1,483	1,531
Interest income (amortization of net unrealized losses (gains) on available for sale securities transferred to held to maturity securities)	76	(1,441)	(2,499)	(4,465)
Income tax (expense) benefit	509	9,074	(239)	(19,352)
Total other comprehensive income (loss)	(818)	(14,707)	391	31,362
Ending Balance	$ (54,288)	$ (1,254)	$ (54,288)	$ (1,254)