Associated Banc-Corp (ASB) 10-Q 28 Jul 17 2017 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2017	Jul. 27, 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	Jun. 30, 2017
Amendment Flag	false
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	Q2
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		151,342,987

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands		Jun. 30, 2017	Dec. 31, 2016
ASSETS
Cash and due from banks		$ 396,677	$ 446,558
Interest-bearing deposits in other financial institutions		126,232	149,175
Federal funds sold and securities purchased under agreements to resell		43,000	46,500
Investment securities held to maturity, at amortized cost		2,255,395	1,273,536
Investment securities available for sale, at fair value		3,687,470	4,680,226
Federal Home Loan Bank and Federal Reserve Bank stocks, at cost		181,180	140,001
Residential loans held for sale	[1]	41,620	108,010
Commercial loans held for sale		4,772	12,474
Loans		20,783,069	20,054,716
Allowance for loan losses		(281,101)	(278,335)
Loans, net		20,501,968	19,776,381
Premises and equipment, net		328,404	330,315
Goodwill		972,006	971,951
Mortgage servicing rights		59,395	61,476
Other intangible assets		14,530	15,377
Trading assets		48,576	52,398
Other assets		1,107,800	1,074,937
Total assets		29,769,025	29,139,315
LIABILITIES AND STOCKHOLDERS’ EQUITY
Noninterest-bearing demand deposits		5,038,162	5,392,208
Interest-bearing deposits		16,580,018	16,496,240
Total deposits		21,618,180	21,888,448
Federal funds purchased and securities sold under agreements to repurchase		607,669	508,347
Other short-term funding		794,813	583,688
Long-term funding		3,262,120	2,761,795
Trading liabilities		47,143	51,103
Accrued expenses and other liabilities		247,598	254,622
Total liabilities		26,577,523	26,048,003
Stockholders’ equity
Preferred equity		159,929	159,929
Common stock		1,630	1,630
Surplus		1,474,301	1,459,498
Retained earnings		1,747,632	1,695,764
Accumulated other comprehensive income (loss)		(53,470)	(54,679)
Treasury stock, at cost		(138,520)	(170,830)
Total common equity		3,031,573	2,931,383
Total stockholders’ equity		3,191,502	3,091,312
Total liabilities and stockholders’ equity		$ 29,769,025	$ 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)		163,030,209	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)		9,181,834	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 the Notes to the Consolidated Financial Statements.

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Jun. 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		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
INTEREST INCOME
Interest and fees on loans	$ 184,246	$ 163,059	$ 357,895	$ 322,715
Interest and dividends on investment securities:
Taxable	23,658	24,270	47,133	49,786
Tax exempt	8,143	7,894	16,272	15,724
Other interest	1,553	1,318	3,089	2,385
Total interest income	217,600	196,541	424,389	390,610
INTEREST EXPENSE
Interest on deposits	21,180	11,678	38,104	23,444
Interest on Federal funds purchased and securities sold under agreements to repurchase	824	378	1,339	674
Interest on other short-term funding	1,827	845	2,907	1,360
Interest on long-term funding	9,950	6,923	17,946	16,428
Total interest expense	33,781	19,824	60,296	41,906
NET INTEREST INCOME	183,819	176,717	364,093	348,704
Provision for credit losses	12,000	14,000	21,000	34,000
Net interest income after provision for credit losses	171,819	162,717	343,093	314,704
NONINTEREST INCOME
Trust service fees	12,346	11,509	24,281	22,956
Service charges on deposit accounts	16,030	16,444	32,386	32,717
Card-based and other nondeposit fees	13,764	12,717	26,229	24,708
Insurance commissions	20,853	22,005	42,473	43,387
Brokerage and annuity commissions	4,346	4,098	8,679	7,892
Mortgage banking, net	5,027	4,067	9,606	8,271
Capital market fees, net	4,042	3,793	7,925	7,331
Bank owned life insurance income	3,899	2,973	6,514	7,743
Asset gains (losses), net	(466)	(343)	(700)	181
Investment securities gains, net	356	3,116	356	6,214
Other	2,213	1,789	4,492	3,960
Total noninterest income	82,410	82,168	162,241	165,360
NONINTEREST EXPENSE
Personnel expense	104,683	102,129	209,102	203,527
Occupancy	12,832	13,215	28,051	27,017
Equipment	5,234	5,396	10,719	10,842
Technology	15,473	14,450	29,893	28,714
Business development and advertising	7,152	6,591	12,987	14,802
Other intangible amortization	496	539	1,009	1,043
Loan expense	2,974	3,442	5,594	6,663
Legal and professional fees	5,711	4,856	9,877	9,881
Foreclosure / OREO expense	1,182	1,330	2,687	3,207
FDIC expense	8,000	8,750	16,000	16,500
Other	12,579	13,662	24,088	26,135
Total noninterest expense	176,316	174,360	350,007	348,331
Income before income taxes	77,913	70,525	155,327	131,733
Income tax expense	19,930	21,434	41,074	40,108
Net income	57,983	49,091	114,253	91,625
Preferred stock dividends	2,339	2,169	4,669	4,367
Net income available to common equity	$ 55,644	$ 46,922	$ 109,584	$ 87,258
Earnings per common share:
Basic (in usd per share)	$ 0.36	$ 0.31	$ 0.72	$ 0.58
Diluted (in usd per share)	$ 0.36	$ 0.31	$ 0.71	$ 0.58
Average common shares outstanding:
Basic (in shares)	151,573	148,511	151,196	148,556
Diluted (in shares)	154,302	149,530	154,147	149,518

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Statement of Comprehensive Income [Abstract]
Net income	$ 57,983	$ 49,091	$ 114,253	$ 91,625
Investment securities available for sale:
Net unrealized gains	15,218	22,321	18,370	82,743
Net unrealized loss on available for sale securities transferred to held to maturity securities	(9,474)	0	(14,738)	0
Amortization of net unrealized gains on available for sale securities transferred to held to maturity securities	(1,548)	(1,452)	(2,575)	(3,024)
Reclassification adjustment for net gains realized in net income	0	(3,116)	0	(6,214)
Income tax expense	(1,601)	(6,773)	(406)	(28,048)
Other comprehensive income on investment securities available for sale	2,595	10,980	651	45,457
Defined benefit pension and postretirement obligations:
Amortization of prior service cost	(37)	12	(75)	25
Amortization of actuarial losses	487	483	975	965
Income tax expense	(171)	(189)	(342)	(378)
Other comprehensive income on pension and postretirement obligations	279	306	558	612
Total other comprehensive income	2,874	11,286	1,209	46,069
Comprehensive income	$ 60,857	$ 60,377	$ 115,462	$ 137,694

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	91,625	0	0	0	91,625	0	0
Other comprehensive income	46,069	0	0	0	0	46,069	0
Comprehensive income	137,694
Common stock issued:
Stock-based compensation plans, net	4,276	0	0	1,153	(17,478)	0	20,601
Purchase of common stock returned to authorized but unissued	(20,007)	0	(12)	(19,995)	0	0	0
Purchase of treasury stock	(4,018)	0	0	0	0	0	(4,018)
Cash dividends:
Common stock dividends ($0.22 per share in 2016 and $0.24 per share in 2017)	(33,034)	0	0	0	(33,034)	0	0
Preferred stock dividends	(4,367)	0	0	0	(4,367)	0	0
Purchase of preferred stock	(1,248)	(1,178)	0	0	(70)	0	0
Stock-based compensation expense, net	13,210	0	0	13,210	0	0	0
Tax impact of stock-based compensation	395	0	0	395	0	0	0
Ending balance at Jun. 30, 2016	3,030,147	120,201	1,630	1,453,285	1,629,915	13,453	(188,337)
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	114,253	0	0	0	114,253	0	0
Other comprehensive income	1,209	0	0	0	0	1,209	0
Comprehensive income	115,462
Common stock issued:
Stock-based compensation plans, net	20,945	0	0	1,102	(20,912)	0	40,755
Purchase of treasury stock	(8,445)	0	0	0	0	0	(8,445)
Cash dividends:
Common stock dividends ($0.22 per share in 2016 and $0.24 per share in 2017)	(36,804)	0	0	0	(36,804)	0	0
Preferred stock dividends	(4,669)	0	0	0	(4,669)	0	0
Stock-based compensation expense, net	12,667	0	0	12,667	0	0	0
Other	1,034	0	0	1,034	0	0	0
Ending balance at Jun. 30, 2017	$ 3,191,502	$ 159,929	$ 1,630	$ 1,474,301	$ 1,747,632	$ (53,470)	$ (138,520)

Consolidated Statements of Cha7

Consolidated Statements of Changes in Stockholders' Equity (Parenthetical) - $ / shares	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Common Stock
Cash dividends:
Common stock dividends (usd per share)	$ 0.24	$ 0.22

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
CASH FLOWS FROM OPERATING ACTIVITIES
Net income	$ 57,983	$ 49,091	$ 114,253	$ 91,625
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for credit losses	12,000	14,000	21,000	34,000
Depreciation and amortization			23,241	22,914
Addition to valuation allowance on mortgage servicing rights, net			275	2,120
Amortization of mortgage servicing rights			5,084	5,896
Amortization of other intangible assets	496	539	1,009	1,043
Amortization and accretion on earning assets, funding, and other, net			17,889	22,045
Tax impact of stock based compensation			4,035	395
Gain on sales of investment securities, net			(356)	(6,214)
Asset (gains) losses, net	466	343	700	(181)
(Gain) loss on mortgage banking activities, net			4,287	(7,058)
Mortgage loans originated and acquired for sale			(220,284)	(517,838)
Proceeds from sales of mortgage loans held for sale			364,128	491,980
Increase in interest receivable			(757)	(4,875)
Increase (decrease) in interest payable			2,653	(4,739)
Commercial loans held for sale
Other, net			(38,650)	(25,836)
Net cash provided by operating activities			298,507	105,277
CASH FLOWS FROM INVESTING ACTIVITIES
Net increase in loans			(819,198)	(1,281,291)
Purchases of:
Available for sale securities			(417,397)	(495,453)
Held to maturity securities			(70,969)	(112,226)
Federal Home Loan Bank and Federal Reserve Bank stocks			(166,869)	(67,261)
Premises, equipment, and software, net of disposals			(19,289)	(81,461)
Other assets			(6,498)	(3,073)
Proceeds from:
Sales of available for sale securities			0	359,484
Sales of held to maturity securities			16,059	0
Proceeds from Sale of Federal Home Loan Bank Stock			125,690	20,000
Prepayments, calls, and maturities of available for sale investment securities			389,251	371,440
Prepayments, calls, and maturities of held to maturity investment securities			80,976	37,172
Sales, prepayments, calls, and maturities of other assets			6,353	13,362
Net cash paid in acquisition			(217)	(685)
Net cash used in investing activities			(882,108)	(1,239,992)
CASH FLOWS FROM FINANCING ACTIVITIES
Net decrease in deposits			(270,268)	(714,815)
Proceeds from (Repayments of) Short-term Debt			310,447	1,077,141
Proceeds from (Repayments of) Long-term Debt and Capital Securities			(12)	(430,018)
Proceeds from issuance of long-term funding			500,000	1,265,000
Proceeds from issuance of common stock for stock-based compensation plans			20,945	4,276
Purchase of preferred stock			0	(1,248)
Purchase of common stock returned to authorized but unissued			0	(20,007)
Purchase of treasury stock for tax withholding			(8,445)	(4,018)
Cash dividends on common stock			(36,804)	(33,034)
Cash dividends on preferred stock			(4,669)	(4,367)
Net cash provided by financing activities			511,194	1,138,910
Net increase (decrease) in cash and cash equivalents			(72,407)	4,195
Cash and cash equivalents at beginning of period			642,233	473,685	$ 473,685
Cash and cash equivalents at end of period	569,826	477,880	569,826	477,880	$ 642,233
Supplemental disclosures of cash flow information:
Cash paid for interest			57,306	46,316
Cash paid for income taxes			27,461	27,852
Loans and bank premises transferred to other real estate owned			3,267	4,704
Capitalized mortgage servicing rights			3,278	4,149
Loans transferred into held for sale from portfolio, net			62,264	130,694
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	6 Months Ended
	Jun. 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. In preparing the consolidated financial statements, management is required to make estimates and assumptions that affect the reported amounts of assets and liabilities as of the date of the balance sheet and revenues and expenses for the period. Actual results could differ significantly from those estimates. Estimates that are particularly susceptible to significant change include the determination of the allowance for loan losses, goodwill impairment assessment, mortgage servicing rights valuation, and income taxes. Management has evaluated subsequent events for potential recognition or disclosure.

Acquisitions

Acquisitions	6 Months Ended
	Jun. 30, 2017
Business Combinations [Abstract]
Acquisitions	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.

Summary of Significant Accounti

Summary of Significant Accounting Policies	6 Months Ended
	Jun. 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 amendments of the new standard 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 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. 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 amendments require that the equity method investor add the cost of acquiring the additional interest 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 amendments require 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	6 Months Ended
	Jun. 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 June 30, For the Six Months Ended June 30, 2017 2016 2017 2016 (In thousands, except per share data) Net income $ 57,983 $ 49,091 $ 114,253 $ 91,625 Preferred stock dividends (2,339 ) (2,169 ) (4,669 ) (4,367 ) Net income available to common equity $ 55,644 $ 46,922 $ 109,584 $ 87,258 Common shareholder dividends (18,326 ) (16,443 ) (36,577 ) (32,646 ) Unvested share-based payment awards (110 ) (182 ) (227 ) (388 ) Undistributed earnings $ 37,208 $ 30,297 $ 72,780 $ 54,224 Undistributed earnings allocated to common shareholders 36,980 29,963 72,273 53,649 Undistributed earnings allocated to unvested share-based payment awards 228 334 507 575 Undistributed earnings $ 37,208 $ 30,297 $ 72,780 $ 54,224 Basic Distributed earnings to common shareholders $ 18,326 $ 16,443 $ 36,577 $ 32,646 Undistributed earnings allocated to common shareholders 36,980 29,963 72,273 53,649 Total common shareholders earnings, basic $ 55,306 $ 46,406 $ 108,850 $ 86,295 Diluted Distributed earnings to common shareholders $ 18,326 $ 16,443 $ 36,577 $ 32,646 Undistributed earnings allocated to common shareholders 36,980 29,963 72,273 53,649 Total common shareholders earnings, diluted $ 55,306 $ 46,406 $ 108,850 $ 86,295 Weighted average common shares outstanding 151,573 148,511 151,196 148,556 Effect of dilutive common stock awards 1,958 1,019 2,155 962 Effect of dilutive common stock warrants 771 — 796 — Diluted weighted average common shares outstanding 154,302 149,530 154,147 149,518 Basic earnings per common share $ 0.36 $ 0.31 $ 0.72 $ 0.58 Diluted earnings per common share $ 0.36 $ 0.31 $ 0.71 $ 0.58 Anti-dilutive common stock options of approximately 1 million and 4 million for the three months ended June 30, 2017 and 2016 , respectively, and 900,000 and 4 million for the six months ended June 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 six months ended June 30, 2016 , but excluded from the calculation of diluted earnings per common shares as the effect would have been anti-dilutive.

Stock-Based Compensation

Stock-Based Compensation	6 Months Ended
	Jun. 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 six 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 six months ended June 30, 2017 is presented below. Stock Options Shares Weighted Average Exercise Price Weighted Average Remaining Contractual Term Aggregate Intrinsic Value (000s) Outstanding at December 31, 2016 6,357,843 $ 17.67 6.10 $ 47,902 Granted 799,558 $ 25.61 Exercised (1,217,640 ) 16.27 Forfeited or expired (447,751 ) 33.58 Outstanding at June 30, 2017 5,492,010 $ 18.10 6.80 $ 39,339 Options Exercisable at June 30, 2017 3,120,596 $ 16.53 5.47 $ 27,075 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 six months ended June 30, 2017 , the intrinsic value of stock options exercised was approximately $11 million . For the six months ended June 30, 2016 , the intrinsic value of the stock options exercised was $1 million . The total fair value of stock options vested was $4 million and $3 million , respectively, for the six months ended June 30, 2017 and June 30, 2016 . The Corporation recognized compensation expense for the vesting of stock options of $2 million for both the six months ended June 30, 2017 and June 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 June 30, 2017 , the Corporation had approximately $7 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 the first quarter 2021 . The following table summarizes information about the Corporation’s restricted stock activity for the six months ended June 30, 2017 . Restricted Stock Shares Weighted Average Grant Date Fair Value Outstanding at December 31, 2016 2,377,380 $ 17.40 Granted 737,080 25.58 Vested (851,381 ) 17.88 Forfeited (61,616 ) 18.41 Outstanding at June 30, 2017 2,201,463 $ 19.94 The Corporation amortizes the expense related to restricted stock awards as compensation expense over the vesting period specified in the grant. 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 $11 million were recorded for both the six months ended June 30, 2017 and June 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 $26 million of unrecognized compensation costs related to restricted stock awards at June 30, 2017 , that is expected to be recognized over the remaining requisite service periods that extend predominantly through the 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, and regulatory constraints. Such repurchases may occur from time to time in open market purchases, block transactions, private transactions, accelerated share repurchase programs, or similar facilities.

Investment Securities

Investment Securities	6 Months Ended
	Jun. 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. June 30, 2017 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value ($ in Thousands) Investment securities available for sale: U. S. Treasury securities $ 1,004 $ — $ (2 ) $ 1,002 Residential mortgage-related securities: FNMA / FHLMC 534,058 13,873 (1,406 ) 546,525 GNMA 1,729,386 1,894 (17,102 ) 1,714,178 Private-label 1,102 — (16 ) 1,086 GNMA commercial mortgage-related securities 1,443,501 74 (23,703 ) 1,419,872 Other securities (debt and equity) 4,718 116 (27 ) 4,807 Total investment securities available for sale $ 3,713,769 $ 15,957 $ (42,256 ) $ 3,687,470 Investment securities held to maturity: Obligations of state and political subdivisions (municipal securities) $ 1,162,920 $ 13,766 $ (4,320 ) $ 1,172,366 Residential mortgage-related securities: FNMA / FHLMC 43,575 430 (566 ) 43,439 GNMA 473,517 4,048 (3,214 ) 474,351 GNMA commercial mortgage-related securities 575,383 8,964 (11,181 ) 573,166 Total investment securities held to maturity $ 2,255,395 $ 27,208 $ (19,281 ) $ 2,263,322 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: 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 June 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 $ 1,500 $ 1,506 $ 41,085 $ 33,447 Due after one year through five years 4,204 4,175 239,986 246,760 Due after five years through ten years — — 261,149 265,255 Due after ten years — — 620,700 626,904 Total debt securities 5,704 5,681 1,162,920 1,172,366 Residential mortgage-related securities: FNMA / FHLMC 534,058 546,525 43,575 43,439 GNMA 1,729,386 1,714,178 473,517 474,351 Private-label 1,102 1,086 — — GNMA commercial mortgage-related securities 1,443,501 1,419,872 575,383 573,166 Equity securities 18 128 — — Total investment securities $ 3,713,769 $ 3,687,470 $ 2,255,395 $ 2,263,322 Ratio of Fair Value to Amortized Cost 99.3 % 100.4 % During the first six months of 2017 , the Corporation reclassified approximately $1 billion of GNMA residential mortgage-related securities and GNMA commercial mortgage-related securities from available for sale to held to maturity. The GNMA residential and commercial mortgage-related securities are principally securities with a CRA component in the underlying collateral. The reclassification of these investment securities was accounted for at fair value. Management elected to transfer these investment securities as the Corporation has the positive intent and ability to hold these investment securities to maturity. The proceeds from the sale of investment securities for the first six months ended June 30, 2017 and 2016 are shown below. Six Months Ended June 30, 2017 2016 ($ in Thousands) Gross gains on available for sale securities $ — $ 6,403 Gross gains on held to maturity securities 361 — Total gains 361 6,403 Gross losses on available for sale securities — (189 ) Gross losses on held to maturity securities $ (5 ) $ — Total losses $ (5 ) $ (189 ) Investment securities gains, net $ 356 $ 6,214 Proceeds from sales of investment securities $ 16,059 $ 359,484 During the first six months of 2017, the Corporation sold approximately $16 million of municipal securities classified as held to maturity due to credit concerns stemming from budgetary pressure and continued credit rating deterioration concerns in the State of Illinois. These sales resulted in a net gain of approximately $356,000 . Investment securities with a carrying value of approximately $2 billion and $1.8 billion at June 30, 2017 , and December 31, 2016 , respectively, were pledged to secure certain deposits or for other purposes as required or permitted by law. The following represents gross unrealized losses and the related fair value of investment securities available for sale and held to maturity, aggregated by investment category and length of time individual securities have been in a continuous unrealized loss position, at June 30, 2017 . Less than 12 months 12 months or more Total June 30, 2017 Number of Securities Unrealized Losses Fair Value Number of Securities Unrealized Losses Fair Value Unrealized Losses Fair Value ($ in Thousands) Investment securities available for sale: U.S. Treasury securities 1 $ (2 ) $ 1,002 — $ — $ — $ (2 ) $ 1,002 Residential mortgage-related securities: FNMA / FHLMC 18 (1,406 ) 223,326 — — — (1,406 ) 223,326 GNMA 42 (16,220 ) 1,186,468 1 (882 ) 35,695 (17,102 ) 1,222,163 Private-label — — — 1 (16 ) 1,084 (16 ) 1,084 GNMA commercial mortgage-related securities 54 (8,627 ) 850,180 31 (15,076 ) 496,698 (23,703 ) 1,346,878 Other securities (debt and equity) 3 (27 ) 2,173 — — — (27 ) 2,173 Total 118 $ (26,282 ) $ 2,263,149 33 $ (15,974 ) $ 533,477 $ (42,256 ) $ 2,796,626 Investment securities held to maturity: Municipal securities 301 $ (4,186 ) $ 222,642 9 $ (134 ) $ 4,814 $ (4,320 ) $ 227,456 Residential mortgage-related securities: FNMA / FHLMC 18 (377 ) 25,507 1 (189 ) 5,657 (566 ) 31,164 GNMA 45 (3,192 ) 358,551 1 (22 ) 1,246 (3,214 ) 359,797 GNMA commercial mortgage-related securities 14 (3,683 ) 301,594 10 (7,498 ) 241,385 (11,181 ) 542,979 Total 378 $ (11,438 ) $ 908,294 21 $ (7,843 ) $ 253,102 $ (19,281 ) $ 1,161,396 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: 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 June 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 June 30, 2017 , and December 31, 2016 , the Corporation had FHLB stock of $106 million and $65 million , respectively. The Corporation had Federal Reserve Bank stock of $76 million and $75 million at June 30, 2017 and December 31, 2016 , respectively.

Loans

Loans	6 Months Ended
	Jun. 30, 2017
Receivables [Abstract]
Loans	Loans The period end loan composition was as follows. June 30, December 31, ($ in Thousands) Commercial and industrial $ 6,571,000 $ 6,489,014 Commercial real estate — owner occupied 845,336 897,724 Commercial and business lending 7,416,336 7,386,738 Commercial real estate — investor 3,329,585 3,574,732 Real estate construction 1,651,805 1,432,497 Commercial real estate lending 4,981,390 5,007,229 Total commercial 12,397,726 12,393,967 Residential mortgage 7,115,457 6,332,327 Home equity 897,111 934,443 Other consumer 372,775 393,979 Total consumer 8,385,343 7,660,749 Total loans $ 20,783,069 $ 20,054,716 The following table presents commercial and consumer loans by credit quality indicator at June 30, 2017 . Pass Special Mention Potential Problem Nonaccrual Total ($ in Thousands) Commercial and industrial $ 6,183,037 $ 103,881 $ 142,607 $ 141,475 $ 6,571,000 Commercial real estate - owner occupied 754,446 14,366 60,724 15,800 845,336 Commercial and business lending 6,937,483 118,247 203,331 157,275 7,416,336 Commercial real estate - investor 3,260,187 13,623 48,569 7,206 3,329,585 Real estate construction 1,621,198 19,989 8,901 1,717 1,651,805 Commercial real estate lending 4,881,385 33,612 57,470 8,923 4,981,390 Total commercial 11,818,868 151,859 260,801 166,198 12,397,726 Residential mortgage 7,060,673 1,233 1,576 51,975 7,115,457 Home equity 882,253 1,168 208 13,482 897,111 Other consumer 372,018 524 — 233 372,775 Total consumer 8,314,944 2,925 1,784 65,690 8,385,343 Total $ 20,133,812 $ 154,784 $ 262,585 $ 231,888 $ 20,783,069 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 June 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 $ 6,428,022 $ 1,042 $ 213 $ 248 $ 141,475 $ 6,571,000 Commercial real estate - owner occupied 828,252 1,136 148 — 15,800 845,336 Commercial and business lending 7,256,274 2,178 361 248 157,275 7,416,336 Commercial real estate - investor 3,321,480 899 — — 7,206 3,329,585 Real estate construction 1,649,953 40 95 — 1,717 1,651,805 Commercial real estate lending 4,971,433 939 95 — 8,923 4,981,390 Total commercial 12,227,707 3,117 456 248 166,198 12,397,726 Residential mortgage 7,054,317 8,163 1,002 — 51,975 7,115,457 Home equity 877,705 4,755 1,169 — 13,482 897,111 Other consumer 369,509 1,113 633 1,287 233 372,775 Total consumer 8,301,531 14,031 2,804 1,287 65,690 8,385,343 Total $ 20,529,238 $ 17,148 $ 3,260 $ 1,535 $ 231,888 $ 20,783,069 (a) The recorded investment in loans past due 90 days or more and still accruing totaled $2 million at June 30, 2017 (the same as the reported balances for the accruing loans noted above). (b) Of the total nonaccrual loans, $180 million or 78% were current with respect to payment at June 30, 2017 . The following table presents loans by past due status at December 31, 2016 . Current 30-59 Days Past Due 60-89 Days Past Due 90 Days or More Past Due (a) Nonaccrual (b) Total ($ 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, $224 million or 81% were current with respect to payment at December 31, 2016 . The following table presents impaired loans at June 30, 2017 . Recorded Unpaid Related Average Interest ($ in Thousands) Loans with a related allowance Commercial and industrial $ 89,563 $ 94,231 $ 17,882 $ 95,205 $ 635 Commercial real estate — owner occupied 7,249 9,154 526 6,086 93 Commercial and business lending 96,812 103,385 18,408 101,291 728 Commercial real estate — investor 15,832 16,111 330 15,782 767 Real estate construction 1,819 2,188 707 1,868 54 Commercial real estate lending 17,651 18,299 1,037 17,650 821 Total commercial 114,463 121,684 19,445 118,941 1,549 Residential mortgage 60,209 65,163 10,649 60,831 1,112 Home equity 20,927 22,907 9,665 21,232 484 Other consumer 1,315 1,342 229 1,335 12 Total consumer 82,451 89,412 20,543 83,398 1,608 Total loans (a) $ 196,914 $ 211,096 $ 39,988 $ 202,339 $ 3,157 Loans with no related allowance Commercial and industrial $ 83,452 $ 107,471 $ — $ 104,989 $ 173 Commercial real estate — owner occupied 12,696 13,546 — 12,906 49 Commercial and business lending 96,148 121,017 — 117,895 222 Commercial real estate — investor 6,002 6,466 — 6,071 — Real estate construction 219 222 — 222 — Commercial real estate lending 6,221 6,688 — 6,293 — Total commercial 102,369 127,705 — 124,188 222 Residential mortgage 9,390 10,246 — 9,461 101 Home equity 540 543 — 540 — Other consumer — — — — — Total consumer 9,930 10,789 — 10,001 101 Total loans (a) $ 112,299 $ 138,494 $ — $ 134,189 $ 323 Total Commercial and industrial $ 173,015 $ 201,702 $ 17,882 $ 200,194 $ 808 Commercial real estate — owner occupied 19,945 22,700 526 18,992 142 Commercial and business lending 192,960 224,402 18,408 219,186 950 Commercial real estate — investor 21,834 22,577 330 21,853 767 Real estate construction 2,038 2,410 707 2,090 54 Commercial real estate lending 23,872 24,987 1,037 23,943 821 Total commercial 216,832 249,389 19,445 243,129 1,771 Residential mortgage 69,599 75,409 10,649 70,292 1,213 Home equity 21,467 23,450 9,665 21,772 484 Other consumer 1,315 1,342 229 1,335 12 Total consumer 92,381 100,201 20,543 93,399 1,709 Total loans (a) $ 309,213 $ 349,590 $ 39,988 $ 336,528 $ 3,480 (a) The net recorded investment (defined as recorded investment, net of the related allowance) of the impaired loans represented 77% of the unpaid principal balance at June 30, 2017 . The following table presents impaired loans 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 $ 101,770 $ 107,813 $ 21,617 $ 111,211 $ 2,512 Commercial real estate — owner occupied 6,595 8,641 295 7,111 274 Commercial and business lending 108,365 116,454 21,912 118,322 2,786 Commercial real estate — investor 27,196 27,677 3,541 31,142 2,124 Real estate construction 1,203 1,566 441 1,321 67 Commercial real estate lending 28,399 29,243 3,982 32,463 2,191 Total commercial 136,764 145,697 25,894 150,785 4,977 Residential mortgage 62,362 67,090 11,091 63,825 2,263 Home equity 20,651 22,805 9,312 21,825 1,114 Other consumer 1,235 1,284 186 1,294 29 Total consumer 84,248 91,179 20,589 86,944 3,406 Total loans (a) $ 221,012 $ 236,876 $ 46,483 $ 237,729 $ 8,383 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 $ 215,255 $ 242,676 $ 21,617 $ 229,191 $ 4,031 Commercial real estate — owner occupied 15,034 17,907 295 15,870 412 Commercial and business lending 230,289 260,583 21,912 245,061 4,443 Commercial real estate — investor 33,340 34,155 3,541 38,234 2,124 Real estate construction 1,203 1,566 441 1,321 67 Commercial real estate lending 34,543 35,721 3,982 39,555 2,191 Total commercial 264,832 296,304 25,894 284,616 6,634 Residential mortgage 68,336 74,088 11,091 70,435 2,447 Home equity 20,757 22,912 9,312 21,932 1,118 Other consumer 1,235 1,284 186 1,294 29 Total consumer 90,328 98,284 20,589 93,661 3,594 Total loans (a) $ 355,160 $ 394,588 $ 46,483 $ 378,277 $ 10,228 (a) The net recorded investment (defined as recorded investment, net of the related allowance) of the impaired loans represented 78% 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 $35 million in loans modified in troubled debt restructurings for the six months ended June 30, 2017 , of which approximately $6 million was in accrual status and $29 million was in nonaccrual pending a sustained period of repayment. During the six months ended June 30, 2017 , the commercial and industrial nonaccrual restructured loans increased primarily due to the restructuring of several large oil and gas loans. These loans were included in nonaccrual loans at both June 30, 2017 and December 31, 2016 . The following table presents nonaccrual and performing restructured loans by loan portfolio. June 30, 2017 December 31, 2016 Performing Restructured Loans Nonaccrual Restructured Loans (a) Performing Restructured Loans Nonaccrual Restructured Loans (a) ($ in Thousands) Commercial and industrial $ 31,540 $ 27,016 $ 31,884 $ 1,276 Commercial real estate — owner occupied 4,145 2,145 5,490 2,220 Commercial real estate — investor 14,628 602 15,289 924 Real estate construction 321 164 359 150 Residential mortgage 17,624 19,365 18,100 21,906 Home equity 7,985 2,401 7,756 2,877 Other consumer 1,082 22 979 32 Total $ 77,325 $ 51,715 $ 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 six months ended June 30, 2017 and 2016 , respectively, and the recorded investment and unpaid principal balance as of June 30, 2017 and 2016 respectively. Six Months Ended June 30, 2017 Six Months Ended June 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 24 $ 30,935 $ 52,260 11 $ 2,608 $ 2,676 Commercial real estate — owner occupied 2 716 716 1 120 126 Residential mortgage 36 2,695 2,805 48 3,942 4,171 Home equity 26 674 919 37 1,433 1,554 Total 88 $ 35,020 $ 56,700 97 $ 8,103 $ 8,527 (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 six months ended June 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 six months ended June 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 six months ended June 30, 2017 and 2016 , respectively, as well as the recorded investment in these restructured loans as of June 30, 2017 and 2016 , respectively. Six Months Ended June 30, 2017 Six Months Ended June 30, 2016 Number of Loans Recorded Investment Number of Loans Recorded Investment ($ in Thousands) Commercial real estate — owner occupied — $ — 2 $ 168 Residential mortgage 17 941 25 2,407 Home equity 9 271 11 164 Total 26 $ 1,212 38 $ 2,739 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 A summary of the changes in the allowance for loan losses by portfolio segment for the six months ended June 30, 2017 , was as follows. $ in Thousands Commercial and industrial Commercial real estate - owner occupied Commercial real estate - investor Real estate construction Residential mortgage Home equity Other consumer Total December 31, 2016 $ 140,126 $ 14,034 $ 45,285 $ 26,932 $ 27,046 $ 20,364 $ 4,548 $ 278,335 Charge offs (21,912 ) (83 ) (803 ) (62 ) (1,034 ) (1,196 ) (2,140 ) (27,230 ) Recoveries 6,498 145 163 47 342 1,423 378 8,996 Net charge offs (15,414 ) 62 (640 ) (15 ) (692 ) 227 (1,762 ) (18,234 ) Provision for loan losses 18,295 (5,551 ) (3,155 ) 4,571 5,212 (351 ) 1,979 21,000 June 30, 2017 $ 143,007 $ 8,545 $ 41,490 $ 31,488 $ 31,566 $ 20,240 $ 4,765 $ 281,101 Allowance for loan losses: Impaired loans: Individually evaluated $ 17,350 $ 187 $ 183 $ — $ 106 $ — $ — $ 17,826 Collectively evaluated 532 339 147 707 10,543 9,665 229 22,162 Total impaired loans 17,882 526 330 707 10,649 9,665 229 39,988 Non-impaired loans: Collectively evaluated 125,125 8,019 41,160 30,781 20,917 10,575 4,536 241,113 Total $ 143,007 $ 8,545 $ 41,490 $ 31,488 $ 31,566 $ 20,240 $ 4,765 $ 281,101 Period end loan balances: Impaired loans: Individually evaluated $ 140,061 $ 15,303 $ 6,799 $ 220 $ 11,060 $ 643 $ — $ 174,086 Collectively evaluated 32,954 4,642 15,035 1,818 58,539 20,824 1,315 135,127 Total impaired loans 173,015 19,945 21,834 2,038 69,599 21,467 1,315 309,213 Non-impaired loans: Collectively evaluated 6,397,985 825,391 3,307,751 1,649,767 7,045,858 875,644 371,460 20,473,856 Total $ 6,571,000 $ 845,336 $ 3,329,585 $ 1,651,805 $ 7,115,457 $ 897,111 $ 372,775 $ 20,783,069 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. 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 industrial Commercial real estate - owner occupied Commercial real estate - investor Real estate construction Residential mortgage Home equity Other consumer 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: Impaired loans: Individually evaluated $ 20,836 $ — $ 3,117 $ — $ 147 $ 3 $ — $ 24,103 Collectively evaluated 781 295 424 441 10,944 9,309 186 22,380 Total impaired loans 21,617 295 3,541 441 11,091 9,312 186 46,483 Non-impaired loans: Collectively evaluated 118,509 13,739 41,744 26,491 15,955 11,052 4,362 231,852 Total $ 140,126 $ 14,034 $ 45,285 $ 26,932 $ 27,046 $ 20,364 $ 4,548 $ 278,335 Period end loan balances: Impaired loans: Individually evaluated $ 180,965 $ 8,439 $ 17,322 $ — $ 7,033 $ 650 $ — $ 214,409 Collectively evaluated 34,290 6,595 16,018 1,203 61,303 20,107 1,235 140,751 Total impaired loans 215,255 15,034 33,340 1,203 68,336 20,757 1,235 355,160 Non-impaired loans: Collectively evaluated 6,273,759 882,690 3,541,392 1,431,294 6,263,991 913,686 392,744 19,699,556 Total $ 6,489,014 $ 897,724 $ 3,574,732 $ 1,432,497 $ 6,332,327 $ 934,443 $ 393,979 $ 20,054,716 A summary of the changes in the allowance for unfunded commitments was as follows. Six Months Ended June 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 Balance at end of period $ 25,400 $ 25,400

Goodwill and Other Intangible A

Goodwill and Other Intangible Assets	6 Months Ended
	Jun. 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 were 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 six months of 2017 . At both June 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 $162,000 of other intangibles relating to customer relationships associated with one small insurance acquisition. See Note 2 for additional information on the Corporation's acquisitions. For core deposit intangibles and other intangibles, changes in the gross carrying amount, accumulated amortization, and net book value were as follows. Six Months Ended June 30, 2017 Year Ended December 31, 2016 ($ 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 (18,042 ) (17,145 ) Net book value $ 14,530 $ 15,265 Additions during the period $ 162 $ 1,012 Amortization during the year $ 897 $ 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 at minimum quarterly evaluates its mortgage servicing rights asset for impairment. 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. Six Months Ended June 30, 2017 Year Ended December 31, 2016 ($ in Thousands) Mortgage servicing rights Mortgage servicing rights at beginning of period $ 62,085 $ 62,150 Additions 3,278 12,262 Amortization (5,084 ) (12,327 ) Mortgage servicing rights at end of period $ 60,279 $ 62,085 Valuation allowance at beginning of period (609 ) (809 ) (Additions) recoveries, net (275 ) 200 Valuation allowance at end of period (884 ) (609 ) Mortgage servicing rights, net $ 59,395 $ 61,476 Fair value of mortgage servicing rights $ 64,627 $ 73,149 Portfolio of residential mortgage loans serviced for others (“servicing portfolio”) $ 7,768,374 $ 7,974,742 Mortgage servicing rights, net to servicing portfolio 0.76 % 0.77 % Mortgage servicing rights expense (a) $ 5,359 $ 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 June 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) Six months ending December 31, 2017 $ 901 $ 5,046 2018 1,771 8,897 2019 1,472 7,476 2020 1,355 6,292 2021 1,331 5,315 2022 1,308 4,515 Beyond 2022 6,392 22,738 Total Estimated Amortization Expense $ 14,530 $ 60,279

Short and Long-Term Funding

Short and Long-Term Funding	6 Months Ended
	Jun. 30, 2017
Debt Disclosure [Abstract]
Short and Long-Term Funding	Short and Long-Term Funding 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) were as follows. June 30, 2017 December 31, 2016 ($ in Thousands) Short-Term Funding Federal funds purchased $ 345,350 $ 208,150 Securities sold under agreements to repurchase 262,319 300,197 Federal funds purchased and securities sold under agreements to repurchase $ 607,669 $ 508,347 FHLB advances 697,000 482,000 Commercial paper 97,813 101,688 Other short-term funding 794,813 583,688 Total short-term funding $ 1,402,482 $ 1,092,035 Long-Term Funding FHLB advances $ 2,765,176 $ 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 (3,056 ) (3,393 ) Total long-term funding 3,262,120 2,761,795 Total short and long-term funding $ 4,664,602 $ 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 June 30, 2017 , the Corporation pledged agency mortgage-related securities with a fair value of $381 million as collateral for the repurchase agreements. Securities pledged as collateral under repurchase agreements are maintained with the Corporation's safekeeping agents and are monitored on a daily basis due to the market risk of fair value changes in the underlying securities. The Corporation generally pledges excess securities to ensure there is sufficient collateral to satisfy short-term fluctuations in both the repurchase agreement balances and the fair value of the underlying securities. The remaining contractual maturity of the securities sold under agreements to repurchase in the consolidated balance sheets as of June 30, 2017 and December 31, 2016 are presented in the following table. Remaining Contractual Maturity of the Agreements Overnight and Continuous Up to 30 days 30-90 days Greater than 90 days Total June 30, 2017 ($ in Thousands) Repurchase agreements Agency mortgage-related securities $ 262,319 $ — $ — $ — $ 262,319 Total $ 262,319 $ — $ — $ — $ 262,319 December 31, 2016 Repurchase agreements Agency mortgage-related securities $ 300,197 $ — $ — $ — $ 300,197 Total $ 300,197 $ — $ — $ — $ 300,197 Long-Term Funding FHLB advances: At June 30, 2017 , the long-term FHLB advances had a weighted average interest rate of 0.98% , 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% and were issued at a discount.

Derivative and Hedging Activiti

Derivative and Hedging Activities	6 Months Ended
	Jun. 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 was required to pledge $22 million of investment securities as collateral at June 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 June 30, 2017 the Corporation posted $1 million 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. June 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 $ 2,118,409 $ 28,105 Trading assets $ 2,039,323 $ 33,671 Trading assets Interest rate-related instruments — customer and mirror 2,118,409 (27,691 ) Trading liabilities 2,039,323 (33,188 ) Trading liabilities Foreign currency exchange forwards 93,300 1,480 Trading assets 109,675 2,002 Trading assets Foreign currency exchange forwards 92,969 (1,412 ) Trading liabilities 106,251 (1,943 ) Trading liabilities Commodity contracts 304,554 18,991 Trading assets 127,582 16,725 Trading assets Commodity contracts 303,790 (18,040 ) 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. June 30, 2017 December 31, 2016 ($ in Thousands) Notional Amount Fair Balance Sheet Notional Amount Fair Balance Sheet Interest rate lock commitments (mortgage) 356,798 2,680 Other assets 285,345 206 Other assets Forward commitments (mortgage) 151,500 159 Other assets 179,600 2,908 Other assets Purchased options (time deposit) 75,899 1,531 Other assets 80,554 2,576 Other assets Written options (time deposit) 75,899 (1,531 ) 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 For the Six Months Ended June 30, ($ in Thousands) 2017 2016 Derivative Instruments: Interest rate-related instruments — customer and mirror, net Capital market fees, net $ (69 ) $ (1,426 ) Interest rate lock commitments (mortgage) Mortgage banking, net 2,474 3,312 Forward commitments (mortgage) Mortgage banking, net (2,749 ) (4,608 ) Foreign currency exchange forwards Capital market fees, net 9 (48 ) Commodity contracts Capital market fees, net 198 358

Balance Sheet Offsetting

Balance Sheet Offsetting	6 Months Ended
	Jun. 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) June 30, 2017 Derivative assets: Interest and commodity agreements $ 24,322 $ — $ 24,322 $ (16,517 ) $ (7,805 ) $ — Derivative liabilities: Interest and commodity agreements $ 16,517 $ — $ 16,517 $ (16,517 ) $ — $ — 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	6 Months Ended
	Jun. 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. June 30, 2017 December 31, 2016 ($ in Thousands) Commitments to extend credit, excluding commitments to originate residential mortgage loans held for sale (a)(b) $ 8,063,899 $ 8,131,131 Commercial letters of credit (a) 5,839 7,923 Standby letters of credit (c) 242,144 259,632 (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 June 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 June 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 $25 million at both June 30, 2017 and 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 June 30, 2017 , was $114 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 $84 million at June 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. 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 $367,000 and $2 million during the six months ended June 30, 2017 and the year ended December 31, 2016 , respectively. The loss reimbursement and settlement claims paid for the six months ended June 30, 2017 and the year ended December 31, 2016 , respectively were negligible. Make whole requests during 2016 and the first six months of 2017 generally arose from loans sold during the period of January 1, 2012 to June 30, 2017 , which totaled $9.5 billion at the time of sale, and consisted primarily of loans sold to GSEs. As of June 30, 2017 , approximately $6.1 billion of these sold loans remain outstanding. The balance in the mortgage repurchase reserve at the balance sheet date reflects the estimated amount of potential loss the Corporation could incur from repurchasing a loan, as well as loss reimbursements, indemnifications, and other settlement resolutions. The following summarizes the changes in the mortgage repurchase reserve. Six Months Ended June 30, 2017 Year Ended December 31, 2016 ($ in Thousands) Balance at beginning of period $ 900 $ 1,197 Repurchase provision expense 109 456 Adjustments to provision expense — (750 ) Charge offs, net (18 ) (3 ) Balance at end of period $ 991 $ 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 June 30, 2017 , and December 31, 2016 , there were approximately $74 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 June 30, 2017 and December 31, 2016 , there were $85 million and $98 million , respectively, of such residential mortgage loans with credit risk recourse, upon which there have been negligible historical losses to the Corporation.

Fair Value Measurements

Fair Value Measurements	6 Months Ended
	Jun. 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). 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. Assets and Liabilities Measured at Fair Value on a Recurring Basis 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 June 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 instrument, 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 June 30, 2017 and December 31, 2016 , aggregated by the level in the fair value hierarchy within which those measurements fall. Fair Value Hierarchy June 30, 2017 December 31, 2016 ($ in Thousands) Assets: Investment securities available for sale: U.S. Treasury securities Level 1 $ 1,002 $ 1,000 Residential mortgage-related securities: FNMA / FHLMC Level 2 546,525 639,930 GNMA Level 2 1,714,178 2,004,475 Private-label Level 2 1,086 1,121 GNMA commercial mortgage-related securities Level 2 1,419,872 2,028,898 Other securities (debt and equity) Level 1 1,634 1,602 Other securities (debt and equity) Level 2 3,173 3,000 Other securities (debt and equity) Level 3 — 200 Total investment securities available for sale Level 1 2,636 2,602 Total investment securities available for sale Level 2 3,684,834 4,677,424 Total investment securities available for sale Level 3 — 200 Residential loans held for sale (a) Level 2 41,620 — Interest rate-related instruments Level 2 28,105 33,671 Foreign currency exchange forwards Level 2 1,480 2,002 Interest rate lock commitments to originate residential mortgage loans held for sale Level 3 2,680 206 Forward commitments to sell residential mortgage loans Level 3 159 2,908 Commodity contracts Level 2 18,991 16,725 Purchased options (time deposit) Level 2 1,531 2,576 Liabilities: Interest rate-related instruments Level 2 $ 27,691 $ 33,188 Foreign currency exchange forwards Level 2 1,412 1,943 Commodity contracts Level 2 18,040 15,972 Written options (time deposit) Level 2 1,531 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 six months ended June 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 — (275 ) Transfer out of level 3 securities (a) (200 ) — Balance June 30, 2017 $ — $ 2,839 (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 or nonrecurring basis as of June 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 June 30, 2017 , the closing ratio was 88% . 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 was based on what secondary markets are currently offering for portfolios with similar characteristics, 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 June 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. 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 loans held for sale, impaired loans, and mortgage servicing rights 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 June 30, 2017 Assets: Commercial loans held for sale (a) Level 2 $ 4,772 Provision for credit losses $ — Impaired loans (c) Level 3 74,937 Provision for credit losses (d) (16,462 ) Other real estate owned Level 2 1,999 Foreclosure / OREO expense, net (621 ) Mortgage servicing rights Level 3 64,627 Mortgage banking, net (275 ) 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 June 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. 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 June 30, 2017 Mortgage servicing rights Discounted cash flow Discount rate 11% Mortgage servicing rights Discounted cash flow Constant prepayment rate 11% Impaired Loans Appraisals / Discounted cash flow Collateral / Discount factor 20% 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. June 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 $ 396,677 $ 396,677 $ 446,558 $ 446,558 Interest-bearing deposits in other financial institutions Level 1 126,232 126,232 149,175 149,175 Federal funds sold and securities purchased under agreements to resell Level 1 43,000 43,000 46,500 46,500 Investment securities held to maturity Level 2 2,255,395 2,263,322 1,273,536 1,264,674 Investment securities available for sale Level 1 2,636 2,636 2,602 2,602 Investment securities available for sale Level 2 3,684,834 3,684,834 4,677,424 4,677,424 Investment securities available for sale Level 3 — — 200 200 FHLB and Federal Reserve Bank stocks Level 2 181,180 181,180 140,001 140,001 Commercial loans held for sale Level 2 4,772 4,772 12,474 12,474 Residential loans held for sale Level 2 41,620 41,620 108,010 108,010 Loans, net Level 3 20,501,968 20,377,586 19,776,381 19,680,317 Bank owned life insurance Level 2 588,440 588,440 585,290 585,290 Derivatives (trading and other assets) Level 2 50,107 50,107 54,974 54,974 Derivatives (trading and other assets) Level 3 2,839 2,839 3,114 3,114 Financial liabilities: Noninterest-bearing demand, savings, interest-bearing demand, and money market accounts Level 3 $ 19,677,850 $ 19,677,850 $ 20,282,321 $ 20,282,321 Brokered CDs and other time deposits Level 2 1,940,330 1,940,330 1,606,127 1,606,127 Short-term funding Level 2 1,402,482 1,402,482 1,092,035 1,092,035 Long-term funding Level 2 3,262,120 3,288,139 2,761,795 2,791,841 Standby letters of credit (a) Level 2 2,394 2,394 2,566 2,566 Derivatives (trading and other liabilities) Level 2 48,674 48,674 53,679 53,679 (a) The commitment on standby letters of credit was $242 million and $260 million at June 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 owned life insurance ("BOLI"): The fair value of BOLI approximates the carrying amount, because upon liquidation of these investments, the Corporation would receive the cash surrender value which equals the carrying amount. 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: Fair value estimates are made at a specific point in time, based on relevant market information and information about the financial instrument. These estimates do not reflect any premium or discount that could result from offering for sale at one time the Corporation’s entire holdings of a particular financial instrument. Because no market exists for a significant portion of the Corporation’s financial instruments, fair value estimates are based on judgments regarding future expected loss experience, current economic conditions, risk characteristics of various financial instruments, and other factors. These estimates are subjective in nature and involve uncertainties and matters of significant judgment and, therefore, cannot be determined with precision. Changes in assumptions could significantly affect the estimates.

Retirement Plans

Retirement Plans	6 Months Ended
	Jun. 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 full-time employees. 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 Plans for three and six months ended June 30, 2017 and 2016 were as follows. Three Months Ended June 30, Six Months Ended June 30, 2017 2016 2017 2016 ($ in Thousands) Components of Net Periodic Benefit Cost Pension Plan: Service cost $ 1,782 $ 1,725 $ 3,563 $ 3,450 Interest cost 1,756 1,780 3,512 3,560 Expected return on plan assets (4,882 ) (5,065 ) (9,763 ) (10,130 ) Amortization of prior service cost (18 ) 12 (37 ) 25 Amortization of actuarial loss 487 483 975 965 Total net pension cost $ (875 ) $ (1,065 ) $ (1,750 ) $ (2,130 ) Postretirement Plan: Interest cost $ 24 $ 36 $ 48 $ 72 Amortization of prior service cost (19 ) — (38 ) — Total net periodic benefit cost $ 5 $ 36 $ 10 $ 72

Segment Reporting

Segment Reporting	6 Months Ended
	Jun. 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). Information about the Corporation’s segments is presented below. Segment Income Statement Data ($ in Thousands) Corporate and Community, Risk Management Consolidated Six Months Ended June 30, 2017 Net interest income $ 179,259 $ 179,059 $ 5,775 $ 364,093 Noninterest income 24,490 130,679 7,072 162,241 Total revenue 203,749 309,738 12,847 526,334 Credit provision* 23,050 10,271 (12,321 ) 21,000 Noninterest expense 76,897 241,339 31,771 350,007 Income (loss) before income taxes 103,802 58,128 (6,603 ) 155,327 Income tax expense (benefit) 34,012 20,345 (13,283 ) 41,074 Net income $ 69,790 $ 37,783 $ 6,680 $ 114,253 Return on average allocated capital (ROCET1)** 12.6 % 13.1 % 1.1 % 10.6 % Six Months Ended June 30, 2016 Net interest income $ 159,233 $ 170,574 $ 18,897 $ 348,704 Noninterest income 22,549 128,880 13,931 165,360 Total revenue 181,782 299,454 32,828 514,064 Credit provision* 27,853 12,388 (6,241 ) 34,000 Noninterest expense 71,543 243,260 33,528 348,331 Income (loss) before income taxes 82,386 43,806 5,541 131,733 Income tax expense (benefit) 27,716 15,332 (2,940 ) 40,108 Net income $ 54,670 $ 28,474 $ 8,481 $ 91,625 Return on average allocated capital (ROCET1)** 10.5 % 9.1 % 3.7 % 9.2 % Segment Balance Sheet Data ($ in Thousands) Corporate and Community, Risk Management Consolidated Average balances for YTD June 2017 Average earning assets $ 10,807,106 $ 9,321,564 $ 6,414,384 $ 26,543,054 Average loans 10,797,831 9,319,719 181,049 20,298,599 Average deposits 6,433,870 11,456,200 3,604,524 21,494,594 Average allocated capital (CET1)** $ 1,120,082 $ 582,706 $ 378,104 $ 2,080,892 Average balances for YTD June 2016 Average earning assets $ 9,924,378 $ 9,222,677 $ 6,473,156 $ 25,620,211 Average loans 9,913,591 9,221,370 147,447 19,282,408 Average deposits 5,744,533 11,215,704 3,471,729 20,431,966 Average allocated capital (CET1)** $ 1,049,431 $ 630,520 $ 224,910 $ 1,904,861 * The consolidated credit provision is equal to the actual reported provision for credit losses. ** The Federal Reserve establishes capital adequacy requirements for the Corporation, including common equity Tier 1. For segment reporting purposes, the ROCET1 reflects return on average allocated common equity Tier 1. The ROCET1 for the Risk Management and Shared Services segment and the Consolidated Total is inclusive of the annualized effect of the preferred stock dividends. Segment Income Statement Data ($ in Thousands) Corporate and Commercial Specialty Community, Consumer, and Business Risk Management and Shared Services Consolidated Total Three Months Ended June 30, 2017 Net interest income $ 89,871 $ 90,131 $ 3,817 $ 183,819 Noninterest income 12,497 65,809 4,104 82,410 Total revenue 102,368 155,940 7,921 266,229 Credit provision* 11,470 5,764 (5,234 ) 12,000 Noninterest expense 39,418 125,242 11,656 176,316 Income (loss) before income taxes 51,480 24,934 1,499 77,913 Income tax expense (benefit) 16,363 8,727 (5,160 ) 19,930 Net income $ 35,117 $ 16,207 $ 6,659 $ 57,983 Return on average allocated capital (ROCET1)** 12.5 % 11.0 % 4.5 % 10.6 % Three Months Ended June 30, 2016 Net interest income $ 80,069 $ 84,969 $ 11,679 $ 176,717 Noninterest income 10,936 65,132 6,100 82,168 Total revenue 91,005 150,101 17,779 258,885 Credit provision* 15,114 6,246 (7,360 ) 14,000 Noninterest expense 37,140 121,965 15,255 174,360 Income (loss) before income taxes 38,751 21,890 9,884 70,525 Income tax expense (benefit) 13,137 7,662 635 21,434 Net income $ 25,614 $ 14,228 $ 9,249 $ 49,091 Return on average allocated capital (ROCET1)** 9.7 % 9.0 % 13.4 % 9.9 % Segment Balance Sheet Data ($ in Thousands) Corporate and Commercial Specialty Community, Consumer, and Business Risk Management and Shared Services Consolidated Total Three Months Ended June 30, 2017 Average earning assets $ 10,853,881 $ 9,510,571 $ 6,380,103 $ 26,744,555 Average loans 10,841,858 9,508,683 171,449 20,521,990 Average deposits 6,447,190 11,574,028 3,501,931 21,523,149 Average allocated capital (CET1)** $ 1,125,494 $ 588,880 $ 385,451 $ 2,099,825 Three Months Ended June 30, 2016 Average earning assets $ 10,128,726 $ 9,325,036 $ 6,514,287 $ 25,968,049 Average loans 10,115,959 9,323,720 202,306 19,641,985 Average deposits 5,570,919 11,331,214 3,386,820 20,288,953 Average allocated capital (CET1)** $ 1,067,203 $ 633,829 $ 212,209 $ 1,913,241 * The consolidated credit provision is equal to the actual reported provision for credit losses. ** The Federal Reserve establishes capital adequacy requirements for the Corporation, including common equity Tier 1. For segment reporting purposes, the ROCET1 reflects return on average allocated common equity Tier 1. The ROCET1 for the Risk Management and Shared Services segment and the Consolidated Total is inclusive of the annualized effect of the preferred stock dividends.

Accumulated Other Comprehensive

Accumulated Other Comprehensive Income (Loss)	6 Months Ended
	Jun. 30, 2017
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Accumulated Other Comprehensive Income (Loss)	Accumulated Other Comprehensive Income (Loss) The following table summarizes the components , changes, and reclassifications out of accumulated other comprehensive income (loss). ($ in Thousands) Investments 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 before reclassifications 3,632 — 3,632 Amounts reclassified from accumulated other comprehensive income: Personnel expense — 900 900 Interest income (Amortization of net unrealized gains on available for sale securities transferred to held to maturity securities) (2,575 ) — (2,575 ) Income tax expense (406 ) (342 ) (748 ) Net other comprehensive income during period 651 558 1,209 Balance June 30, 2017 $ (19,428 ) $ (34,042 ) $ (53,470 ) Balance January 1, 2016 $ 459 $ (33,075 ) $ (32,616 ) Other comprehensive income before reclassifications 82,743 — 82,743 Amounts reclassified from accumulated other comprehensive income (loss): Investment securities gain, net (6,214 ) — (6,214 ) Personnel expense — 990 990 Interest income (Amortization of net unrealized gains on available for sale securities transferred to held to maturity securities) (3,024 ) — (3,024 ) Income tax expense (28,048 ) (378 ) (28,426 ) Net other comprehensive income during period 45,457 612 46,069 Balance June 30, 2016 $ 45,916 $ (32,463 ) $ 13,453 Investments Defined Benefit Accumulated Balance April 1, 2017 $ (22,023 ) $ (34,321 ) $ (56,344 ) Other comprehensive income before reclassifications 5,744 — 5,744 Amounts reclassified from accumulated other comprehensive income: Personnel expense — 450 450 Interest income (Amortization of net unrealized gains on available for sale securities transferred to held to maturity securities) (1,548 ) — (1,548 ) Income tax expense (1,601 ) (171 ) (1,772 ) Net other comprehensive income during period 2,595 279 2,874 Balance June 30, 2017 $ (19,428 ) $ (34,042 ) $ (53,470 ) Balance April 1, 2016 $ 34,936 $ (32,769 ) $ 2,167 Other comprehensive income before reclassifications 22,321 — 22,321 Amounts reclassified from accumulated other comprehensive income (loss): Investment securities gain, net (3,116 ) — (3,116 ) Personnel expense — 495 495 Interest income (Amortization of net unrealized gains on available for sale securities transferred to held to maturity securities) (1,452 ) — (1,452 ) Income tax expense (6,773 ) (189 ) (6,962 ) Net other comprehensive income during period 10,980 306 11,286 Balance June 30, 2016 $ 45,916 $ (32,463 ) $ 13,453

Recent Developments

Recent Developments	6 Months Ended
	Jun. 30, 2017
Subsequent Events [Abstract]
Recent Developments	Recent Developments On July 20, 2017, the Corporation announced the signing of a definitive merger agreement with Bank Mutual Corporation ("Bank Mutual") in an all-stock stock transaction. Bank Mutual Corporation is a bank holding company and the parent for BankMutual, an Office of the Comptroller of the Currency ("OCC") Chartered national bank. Based in Milwaukee, with consolidated assets of approximately $2.7 billion and deposits of approximately $1.9 billion as of June 30, 2017 , BankMutual was the third largest bank, by deposit market share, headquartered in Wisconsin. Under the terms of the agreement, shareholders of Bank Mutual will receive 0.422 shares of the Corporation's common stock for each share of Bank Mutual common stock. The transaction is valued at approximately $482 million based on the closing stock price on the day preceding the announcement. The transaction is expected to be completed in early 2018, subject to the customary closing conditions, regulatory approvals, and the approval of Bank Mutual's shareholders.

Summary of Significant Accoun26

Summary of Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 30, 2017
New Accounting Pronouncements and Changes in Accounting Principles [Abstract]
Finance, Loan and Lease Receivables, Held-for-sale, Policy [Policy Text Block]	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, Policy [Policy Text Block]	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 amendments of the new standard 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 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. 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 amendments require that the equity method investor add the cost of acquiring the additional interest 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 amendments require 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)	6 Months Ended
	Jun. 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 June 30, For the Six Months Ended June 30, 2017 2016 2017 2016 (In thousands, except per share data) Net income $ 57,983 $ 49,091 $ 114,253 $ 91,625 Preferred stock dividends (2,339 ) (2,169 ) (4,669 ) (4,367 ) Net income available to common equity $ 55,644 $ 46,922 $ 109,584 $ 87,258 Common shareholder dividends (18,326 ) (16,443 ) (36,577 ) (32,646 ) Unvested share-based payment awards (110 ) (182 ) (227 ) (388 ) Undistributed earnings $ 37,208 $ 30,297 $ 72,780 $ 54,224 Undistributed earnings allocated to common shareholders 36,980 29,963 72,273 53,649 Undistributed earnings allocated to unvested share-based payment awards 228 334 507 575 Undistributed earnings $ 37,208 $ 30,297 $ 72,780 $ 54,224 Basic Distributed earnings to common shareholders $ 18,326 $ 16,443 $ 36,577 $ 32,646 Undistributed earnings allocated to common shareholders 36,980 29,963 72,273 53,649 Total common shareholders earnings, basic $ 55,306 $ 46,406 $ 108,850 $ 86,295 Diluted Distributed earnings to common shareholders $ 18,326 $ 16,443 $ 36,577 $ 32,646 Undistributed earnings allocated to common shareholders 36,980 29,963 72,273 53,649 Total common shareholders earnings, diluted $ 55,306 $ 46,406 $ 108,850 $ 86,295 Weighted average common shares outstanding 151,573 148,511 151,196 148,556 Effect of dilutive common stock awards 1,958 1,019 2,155 962 Effect of dilutive common stock warrants 771 — 796 — Diluted weighted average common shares outstanding 154,302 149,530 154,147 149,518 Basic earnings per common share $ 0.36 $ 0.31 $ 0.72 $ 0.58 Diluted earnings per common share $ 0.36 $ 0.31 $ 0.71 $ 0.58

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	6 Months Ended
	Jun. 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 six 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 six months ended June 30, 2017 is presented below. Stock Options Shares Weighted Average Exercise Price Weighted Average Remaining Contractual Term Aggregate Intrinsic Value (000s) Outstanding at December 31, 2016 6,357,843 $ 17.67 6.10 $ 47,902 Granted 799,558 $ 25.61 Exercised (1,217,640 ) 16.27 Forfeited or expired (447,751 ) 33.58 Outstanding at June 30, 2017 5,492,010 $ 18.10 6.80 $ 39,339 Options Exercisable at June 30, 2017 3,120,596 $ 16.53 5.47 $ 27,075
Summary of Restricted Stock Awards Activity (Excluding Salary Shares)	The following table summarizes information about the Corporation’s restricted stock activity for the six months ended June 30, 2017 . Restricted Stock Shares Weighted Average Grant Date Fair Value Outstanding at December 31, 2016 2,377,380 $ 17.40 Granted 737,080 25.58 Vested (851,381 ) 17.88 Forfeited (61,616 ) 18.41 Outstanding at June 30, 2017 2,201,463 $ 19.94

Investment Securities (Tables)

Investment Securities (Tables)	6 Months Ended
	Jun. 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. June 30, 2017 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value ($ in Thousands) Investment securities available for sale: U. S. Treasury securities $ 1,004 $ — $ (2 ) $ 1,002 Residential mortgage-related securities: FNMA / FHLMC 534,058 13,873 (1,406 ) 546,525 GNMA 1,729,386 1,894 (17,102 ) 1,714,178 Private-label 1,102 — (16 ) 1,086 GNMA commercial mortgage-related securities 1,443,501 74 (23,703 ) 1,419,872 Other securities (debt and equity) 4,718 116 (27 ) 4,807 Total investment securities available for sale $ 3,713,769 $ 15,957 $ (42,256 ) $ 3,687,470 Investment securities held to maturity: Obligations of state and political subdivisions (municipal securities) $ 1,162,920 $ 13,766 $ (4,320 ) $ 1,172,366 Residential mortgage-related securities: FNMA / FHLMC 43,575 430 (566 ) 43,439 GNMA 473,517 4,048 (3,214 ) 474,351 GNMA commercial mortgage-related securities 575,383 8,964 (11,181 ) 573,166 Total investment securities held to maturity $ 2,255,395 $ 27,208 $ (19,281 ) $ 2,263,322 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: 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. June 30, 2017 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value ($ in Thousands) Investment securities available for sale: U. S. Treasury securities $ 1,004 $ — $ (2 ) $ 1,002 Residential mortgage-related securities: FNMA / FHLMC 534,058 13,873 (1,406 ) 546,525 GNMA 1,729,386 1,894 (17,102 ) 1,714,178 Private-label 1,102 — (16 ) 1,086 GNMA commercial mortgage-related securities 1,443,501 74 (23,703 ) 1,419,872 Other securities (debt and equity) 4,718 116 (27 ) 4,807 Total investment securities available for sale $ 3,713,769 $ 15,957 $ (42,256 ) $ 3,687,470 Investment securities held to maturity: Obligations of state and political subdivisions (municipal securities) $ 1,162,920 $ 13,766 $ (4,320 ) $ 1,172,366 Residential mortgage-related securities: FNMA / FHLMC 43,575 430 (566 ) 43,439 GNMA 473,517 4,048 (3,214 ) 474,351 GNMA commercial mortgage-related securities 575,383 8,964 (11,181 ) 573,166 Total investment securities held to maturity $ 2,255,395 $ 27,208 $ (19,281 ) $ 2,263,322 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: 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 available for sale by contractual maturity	The amortized cost and fair values of investment securities available for sale and held to maturity at June 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 $ 1,500 $ 1,506 $ 41,085 $ 33,447 Due after one year through five years 4,204 4,175 239,986 246,760 Due after five years through ten years — — 261,149 265,255 Due after ten years — — 620,700 626,904 Total debt securities 5,704 5,681 1,162,920 1,172,366 Residential mortgage-related securities: FNMA / FHLMC 534,058 546,525 43,575 43,439 GNMA 1,729,386 1,714,178 473,517 474,351 Private-label 1,102 1,086 — — GNMA commercial mortgage-related securities 1,443,501 1,419,872 575,383 573,166 Equity securities 18 128 — — Total investment securities $ 3,713,769 $ 3,687,470 $ 2,255,395 $ 2,263,322 Ratio of Fair Value to Amortized Cost 99.3 % 100.4 %
Realized gains and losses and proceeds from sale	The proceeds from the sale of investment securities for the first six months ended June 30, 2017 and 2016 are shown below. Six Months Ended June 30, 2017 2016 ($ in Thousands) Gross gains on available for sale securities $ — $ 6,403 Gross gains on held to maturity securities 361 — Total gains 361 6,403 Gross losses on available for sale securities — (189 ) Gross losses on held to maturity securities $ (5 ) $ — Total losses $ (5 ) $ (189 ) Investment securities gains, net $ 356 $ 6,214 Proceeds from sales of investment securities $ 16,059 $ 359,484
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 June 30, 2017 . Less than 12 months 12 months or more Total June 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 ) $ 1,002 — $ — $ — $ (2 ) $ 1,002 Residential mortgage-related securities: FNMA / FHLMC 18 (1,406 ) 223,326 — — — (1,406 ) 223,326 GNMA 42 (16,220 ) 1,186,468 1 (882 ) 35,695 (17,102 ) 1,222,163 Private-label — — — 1 (16 ) 1,084 (16 ) 1,084 GNMA commercial mortgage-related securities 54 (8,627 ) 850,180 31 (15,076 ) 496,698 (23,703 ) 1,346,878 Other securities (debt and equity) 3 (27 ) 2,173 — — — (27 ) 2,173 Total 118 $ (26,282 ) $ 2,263,149 33 $ (15,974 ) $ 533,477 $ (42,256 ) $ 2,796,626 Investment securities held to maturity: Municipal securities 301 $ (4,186 ) $ 222,642 9 $ (134 ) $ 4,814 $ (4,320 ) $ 227,456 Residential mortgage-related securities: FNMA / FHLMC 18 (377 ) 25,507 1 (189 ) 5,657 (566 ) 31,164 GNMA 45 (3,192 ) 358,551 1 (22 ) 1,246 (3,214 ) 359,797 GNMA commercial mortgage-related securities 14 (3,683 ) 301,594 10 (7,498 ) 241,385 (11,181 ) 542,979 Total 378 $ (11,438 ) $ 908,294 21 $ (7,843 ) $ 253,102 $ (19,281 ) $ 1,161,396 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: 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)	6 Months Ended
	Jun. 30, 2017
Receivables [Abstract]
Loan composition	The period end loan composition was as follows. June 30, December 31, ($ in Thousands) Commercial and industrial $ 6,571,000 $ 6,489,014 Commercial real estate — owner occupied 845,336 897,724 Commercial and business lending 7,416,336 7,386,738 Commercial real estate — investor 3,329,585 3,574,732 Real estate construction 1,651,805 1,432,497 Commercial real estate lending 4,981,390 5,007,229 Total commercial 12,397,726 12,393,967 Residential mortgage 7,115,457 6,332,327 Home equity 897,111 934,443 Other consumer 372,775 393,979 Total consumer 8,385,343 7,660,749 Total loans $ 20,783,069 $ 20,054,716
Commercial and consumer loans by credit quality indicator	The following table presents commercial and consumer loans by credit quality indicator at June 30, 2017 . Pass Special Mention Potential Problem Nonaccrual Total ($ in Thousands) Commercial and industrial $ 6,183,037 $ 103,881 $ 142,607 $ 141,475 $ 6,571,000 Commercial real estate - owner occupied 754,446 14,366 60,724 15,800 845,336 Commercial and business lending 6,937,483 118,247 203,331 157,275 7,416,336 Commercial real estate - investor 3,260,187 13,623 48,569 7,206 3,329,585 Real estate construction 1,621,198 19,989 8,901 1,717 1,651,805 Commercial real estate lending 4,881,385 33,612 57,470 8,923 4,981,390 Total commercial 11,818,868 151,859 260,801 166,198 12,397,726 Residential mortgage 7,060,673 1,233 1,576 51,975 7,115,457 Home equity 882,253 1,168 208 13,482 897,111 Other consumer 372,018 524 — 233 372,775 Total consumer 8,314,944 2,925 1,784 65,690 8,385,343 Total $ 20,133,812 $ 154,784 $ 262,585 $ 231,888 $ 20,783,069 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 June 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 $ 6,428,022 $ 1,042 $ 213 $ 248 $ 141,475 $ 6,571,000 Commercial real estate - owner occupied 828,252 1,136 148 — 15,800 845,336 Commercial and business lending 7,256,274 2,178 361 248 157,275 7,416,336 Commercial real estate - investor 3,321,480 899 — — 7,206 3,329,585 Real estate construction 1,649,953 40 95 — 1,717 1,651,805 Commercial real estate lending 4,971,433 939 95 — 8,923 4,981,390 Total commercial 12,227,707 3,117 456 248 166,198 12,397,726 Residential mortgage 7,054,317 8,163 1,002 — 51,975 7,115,457 Home equity 877,705 4,755 1,169 — 13,482 897,111 Other consumer 369,509 1,113 633 1,287 233 372,775 Total consumer 8,301,531 14,031 2,804 1,287 65,690 8,385,343 Total $ 20,529,238 $ 17,148 $ 3,260 $ 1,535 $ 231,888 $ 20,783,069 (a) The recorded investment in loans past due 90 days or more and still accruing totaled $2 million at June 30, 2017 (the same as the reported balances for the accruing loans noted above). (b) Of the total nonaccrual loans, $180 million or 78% were current with respect to payment at June 30, 2017 . The following table presents loans by past due status at December 31, 2016 . Current 30-59 Days Past Due 60-89 Days Past Due 90 Days or More Past Due (a) Nonaccrual (b) Total ($ 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, $224 million or 81% were current with respect to payment at December 31, 2016 .
Summarized details of impaired Loans	The following table presents impaired loans at June 30, 2017 . Recorded Unpaid Related Average Interest ($ in Thousands) Loans with a related allowance Commercial and industrial $ 89,563 $ 94,231 $ 17,882 $ 95,205 $ 635 Commercial real estate — owner occupied 7,249 9,154 526 6,086 93 Commercial and business lending 96,812 103,385 18,408 101,291 728 Commercial real estate — investor 15,832 16,111 330 15,782 767 Real estate construction 1,819 2,188 707 1,868 54 Commercial real estate lending 17,651 18,299 1,037 17,650 821 Total commercial 114,463 121,684 19,445 118,941 1,549 Residential mortgage 60,209 65,163 10,649 60,831 1,112 Home equity 20,927 22,907 9,665 21,232 484 Other consumer 1,315 1,342 229 1,335 12 Total consumer 82,451 89,412 20,543 83,398 1,608 Total loans (a) $ 196,914 $ 211,096 $ 39,988 $ 202,339 $ 3,157 Loans with no related allowance Commercial and industrial $ 83,452 $ 107,471 $ — $ 104,989 $ 173 Commercial real estate — owner occupied 12,696 13,546 — 12,906 49 Commercial and business lending 96,148 121,017 — 117,895 222 Commercial real estate — investor 6,002 6,466 — 6,071 — Real estate construction 219 222 — 222 — Commercial real estate lending 6,221 6,688 — 6,293 — Total commercial 102,369 127,705 — 124,188 222 Residential mortgage 9,390 10,246 — 9,461 101 Home equity 540 543 — 540 — Other consumer — — — — — Total consumer 9,930 10,789 — 10,001 101 Total loans (a) $ 112,299 $ 138,494 $ — $ 134,189 $ 323 Total Commercial and industrial $ 173,015 $ 201,702 $ 17,882 $ 200,194 $ 808 Commercial real estate — owner occupied 19,945 22,700 526 18,992 142 Commercial and business lending 192,960 224,402 18,408 219,186 950 Commercial real estate — investor 21,834 22,577 330 21,853 767 Real estate construction 2,038 2,410 707 2,090 54 Commercial real estate lending 23,872 24,987 1,037 23,943 821 Total commercial 216,832 249,389 19,445 243,129 1,771 Residential mortgage 69,599 75,409 10,649 70,292 1,213 Home equity 21,467 23,450 9,665 21,772 484 Other consumer 1,315 1,342 229 1,335 12 Total consumer 92,381 100,201 20,543 93,399 1,709 Total loans (a) $ 309,213 $ 349,590 $ 39,988 $ 336,528 $ 3,480 (a) The net recorded investment (defined as recorded investment, net of the related allowance) of the impaired loans represented 77% of the unpaid principal balance at June 30, 2017 . The following table presents impaired loans 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 $ 101,770 $ 107,813 $ 21,617 $ 111,211 $ 2,512 Commercial real estate — owner occupied 6,595 8,641 295 7,111 274 Commercial and business lending 108,365 116,454 21,912 118,322 2,786 Commercial real estate — investor 27,196 27,677 3,541 31,142 2,124 Real estate construction 1,203 1,566 441 1,321 67 Commercial real estate lending 28,399 29,243 3,982 32,463 2,191 Total commercial 136,764 145,697 25,894 150,785 4,977 Residential mortgage 62,362 67,090 11,091 63,825 2,263 Home equity 20,651 22,805 9,312 21,825 1,114 Other consumer 1,235 1,284 186 1,294 29 Total consumer 84,248 91,179 20,589 86,944 3,406 Total loans (a) $ 221,012 $ 236,876 $ 46,483 $ 237,729 $ 8,383 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 $ 215,255 $ 242,676 $ 21,617 $ 229,191 $ 4,031 Commercial real estate — owner occupied 15,034 17,907 295 15,870 412 Commercial and business lending 230,289 260,583 21,912 245,061 4,443 Commercial real estate — investor 33,340 34,155 3,541 38,234 2,124 Real estate construction 1,203 1,566 441 1,321 67 Commercial real estate lending 34,543 35,721 3,982 39,555 2,191 Total commercial 264,832 296,304 25,894 284,616 6,634 Residential mortgage 68,336 74,088 11,091 70,435 2,447 Home equity 20,757 22,912 9,312 21,932 1,118 Other consumer 1,235 1,284 186 1,294 29 Total consumer 90,328 98,284 20,589 93,661 3,594 Total loans (a) $ 355,160 $ 394,588 $ 46,483 $ 378,277 $ 10,228 (a) The net recorded investment (defined as recorded investment, net of the related allowance) of the impaired loans represented 78% 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. June 30, 2017 December 31, 2016 Performing Restructured Loans Nonaccrual Restructured Loans (a) Performing Restructured Loans Nonaccrual Restructured Loans (a) ($ in Thousands) Commercial and industrial $ 31,540 $ 27,016 $ 31,884 $ 1,276 Commercial real estate — owner occupied 4,145 2,145 5,490 2,220 Commercial real estate — investor 14,628 602 15,289 924 Real estate construction 321 164 359 150 Residential mortgage 17,624 19,365 18,100 21,906 Home equity 7,985 2,401 7,756 2,877 Other consumer 1,082 22 979 32 Total $ 77,325 $ 51,715 $ 79,857 $ 29,385 (a) Nonaccrual restructured loans have been included within nonaccrual loans.
Summary of restructured loans	The following table provides the number of loans modified in a troubled debt restructuring by loan portfolio during the six months ended June 30, 2017 and 2016 , respectively, and the recorded investment and unpaid principal balance as of June 30, 2017 and 2016 respectively. Six Months Ended June 30, 2017 Six Months Ended June 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 24 $ 30,935 $ 52,260 11 $ 2,608 $ 2,676 Commercial real estate — owner occupied 2 716 716 1 120 126 Residential mortgage 36 2,695 2,805 48 3,942 4,171 Home equity 26 674 919 37 1,433 1,554 Total 88 $ 35,020 $ 56,700 97 $ 8,103 $ 8,527 (a) Represents post-modification outstanding recorded investment. (b) Represents pre-modification outstanding recorded investment.
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 six months ended June 30, 2017 and 2016 , respectively, as well as the recorded investment in these restructured loans as of June 30, 2017 and 2016 , respectively. Six Months Ended June 30, 2017 Six Months Ended June 30, 2016 Number of Loans Recorded Investment Number of Loans Recorded Investment ($ in Thousands) Commercial real estate — owner occupied — $ — 2 $ 168 Residential mortgage 17 941 25 2,407 Home equity 9 271 11 164 Total 26 $ 1,212 38 $ 2,739
Changes in the allowance for loan losses by portfolio segment	A summary of the changes in the allowance for loan losses by portfolio segment for the six months ended June 30, 2017 , was as follows. $ in Thousands Commercial and industrial Commercial real estate - owner occupied Commercial real estate - investor Real estate construction Residential mortgage Home equity Other consumer Total December 31, 2016 $ 140,126 $ 14,034 $ 45,285 $ 26,932 $ 27,046 $ 20,364 $ 4,548 $ 278,335 Charge offs (21,912 ) (83 ) (803 ) (62 ) (1,034 ) (1,196 ) (2,140 ) (27,230 ) Recoveries 6,498 145 163 47 342 1,423 378 8,996 Net charge offs (15,414 ) 62 (640 ) (15 ) (692 ) 227 (1,762 ) (18,234 ) Provision for loan losses 18,295 (5,551 ) (3,155 ) 4,571 5,212 (351 ) 1,979 21,000 June 30, 2017 $ 143,007 $ 8,545 $ 41,490 $ 31,488 $ 31,566 $ 20,240 $ 4,765 $ 281,101 Allowance for loan losses: Impaired loans: Individually evaluated $ 17,350 $ 187 $ 183 $ — $ 106 $ — $ — $ 17,826 Collectively evaluated 532 339 147 707 10,543 9,665 229 22,162 Total impaired loans 17,882 526 330 707 10,649 9,665 229 39,988 Non-impaired loans: Collectively evaluated 125,125 8,019 41,160 30,781 20,917 10,575 4,536 241,113 Total $ 143,007 $ 8,545 $ 41,490 $ 31,488 $ 31,566 $ 20,240 $ 4,765 $ 281,101 Period end loan balances: Impaired loans: Individually evaluated $ 140,061 $ 15,303 $ 6,799 $ 220 $ 11,060 $ 643 $ — $ 174,086 Collectively evaluated 32,954 4,642 15,035 1,818 58,539 20,824 1,315 135,127 Total impaired loans 173,015 19,945 21,834 2,038 69,599 21,467 1,315 309,213 Non-impaired loans: Collectively evaluated 6,397,985 825,391 3,307,751 1,649,767 7,045,858 875,644 371,460 20,473,856 Total $ 6,571,000 $ 845,336 $ 3,329,585 $ 1,651,805 $ 7,115,457 $ 897,111 $ 372,775 $ 20,783,069 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 industrial Commercial real estate - owner occupied Commercial real estate - investor Real estate construction Residential mortgage Home equity Other consumer 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: Impaired loans: Individually evaluated $ 20,836 $ — $ 3,117 $ — $ 147 $ 3 $ — $ 24,103 Collectively evaluated 781 295 424 441 10,944 9,309 186 22,380 Total impaired loans 21,617 295 3,541 441 11,091 9,312 186 46,483 Non-impaired loans: Collectively evaluated 118,509 13,739 41,744 26,491 15,955 11,052 4,362 231,852 Total $ 140,126 $ 14,034 $ 45,285 $ 26,932 $ 27,046 $ 20,364 $ 4,548 $ 278,335 Period end loan balances: Impaired loans: Individually evaluated $ 180,965 $ 8,439 $ 17,322 $ — $ 7,033 $ 650 $ — $ 214,409 Collectively evaluated 34,290 6,595 16,018 1,203 61,303 20,107 1,235 140,751 Total impaired loans 215,255 15,034 33,340 1,203 68,336 20,757 1,235 355,160 Non-impaired loans: Collectively evaluated 6,273,759 882,690 3,541,392 1,431,294 6,263,991 913,686 392,744 19,699,556 Total $ 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	A summary of the changes in the allowance for unfunded commitments was as follows. Six Months Ended June 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 Balance at end of period $ 25,400 $ 25,400

Goodwill and Other Intangible31

Goodwill and Other Intangible Assets (Tables)	6 Months Ended
	Jun. 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. Six Months Ended June 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 (18,042 ) (17,145 ) Net book value $ 14,530 $ 15,265 Additions during the period $ 162 $ 1,012 Amortization during the year $ 897 $ 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. Six Months Ended June 30, 2017 Year Ended December 31, 2016 ($ in Thousands) Mortgage servicing rights Mortgage servicing rights at beginning of period $ 62,085 $ 62,150 Additions 3,278 12,262 Amortization (5,084 ) (12,327 ) Mortgage servicing rights at end of period $ 60,279 $ 62,085 Valuation allowance at beginning of period (609 ) (809 ) (Additions) recoveries, net (275 ) 200 Valuation allowance at end of period (884 ) (609 ) Mortgage servicing rights, net $ 59,395 $ 61,476 Fair value of mortgage servicing rights $ 64,627 $ 73,149 Portfolio of residential mortgage loans serviced for others (“servicing portfolio”) $ 7,768,374 $ 7,974,742 Mortgage servicing rights, net to servicing portfolio 0.76 % 0.77 % Mortgage servicing rights expense (a) $ 5,359 $ 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
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 June 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) Six months ending December 31, 2017 $ 901 $ 5,046 2018 1,771 8,897 2019 1,472 7,476 2020 1,355 6,292 2021 1,331 5,315 2022 1,308 4,515 Beyond 2022 6,392 22,738 Total Estimated Amortization Expense $ 14,530 $ 60,279

Short and Long-Term Funding (Ta

Short and Long-Term Funding (Tables)	6 Months Ended
	Jun. 30, 2017
Debt Disclosure [Abstract]
Breakdown of short & long-term debt balances	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) were as follows. June 30, 2017 December 31, 2016 ($ in Thousands) Short-Term Funding Federal funds purchased $ 345,350 $ 208,150 Securities sold under agreements to repurchase 262,319 300,197 Federal funds purchased and securities sold under agreements to repurchase $ 607,669 $ 508,347 FHLB advances 697,000 482,000 Commercial paper 97,813 101,688 Other short-term funding 794,813 583,688 Total short-term funding $ 1,402,482 $ 1,092,035 Long-Term Funding FHLB advances $ 2,765,176 $ 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 (3,056 ) (3,393 ) Total long-term funding 3,262,120 2,761,795 Total short and long-term funding $ 4,664,602 $ 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 June 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 June 30, 2017 ($ in Thousands) Repurchase agreements Agency mortgage-related securities $ 262,319 $ — $ — $ — $ 262,319 Total $ 262,319 $ — $ — $ — $ 262,319 December 31, 2016 Repurchase agreements Agency mortgage-related securities $ 300,197 $ — $ — $ — $ 300,197 Total $ 300,197 $ — $ — $ — $ 300,197

Derivative and Hedging Activi33

Derivative and Hedging Activities (Tables)	6 Months Ended
	Jun. 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. June 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 $ 2,118,409 $ 28,105 Trading assets $ 2,039,323 $ 33,671 Trading assets Interest rate-related instruments — customer and mirror 2,118,409 (27,691 ) Trading liabilities 2,039,323 (33,188 ) Trading liabilities Foreign currency exchange forwards 93,300 1,480 Trading assets 109,675 2,002 Trading assets Foreign currency exchange forwards 92,969 (1,412 ) Trading liabilities 106,251 (1,943 ) Trading liabilities Commodity contracts 304,554 18,991 Trading assets 127,582 16,725 Trading assets Commodity contracts 303,790 (18,040 ) 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. June 30, 2017 December 31, 2016 ($ in Thousands) Notional Amount Fair Balance Sheet Notional Amount Fair Balance Sheet Interest rate lock commitments (mortgage) 356,798 2,680 Other assets 285,345 206 Other assets Forward commitments (mortgage) 151,500 159 Other assets 179,600 2,908 Other assets Purchased options (time deposit) 75,899 1,531 Other assets 80,554 2,576 Other assets Written options (time deposit) 75,899 (1,531 ) 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 For the Six Months Ended June 30, ($ in Thousands) 2017 2016 Derivative Instruments: Interest rate-related instruments — customer and mirror, net Capital market fees, net $ (69 ) $ (1,426 ) Interest rate lock commitments (mortgage) Mortgage banking, net 2,474 3,312 Forward commitments (mortgage) Mortgage banking, net (2,749 ) (4,608 ) Foreign currency exchange forwards Capital market fees, net 9 (48 ) Commodity contracts Capital market fees, net 198 358

Balance Sheet Offsetting (Table

Balance Sheet Offsetting (Tables)	6 Months Ended
	Jun. 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) June 30, 2017 Derivative assets: Interest and commodity agreements $ 24,322 $ — $ 24,322 $ (16,517 ) $ (7,805 ) $ — Derivative liabilities: Interest and commodity agreements $ 16,517 $ — $ 16,517 $ (16,517 ) $ — $ — 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 Shee35

Commitments, Off-Balance Sheet Arrangements, Legal Proceedings and Regulatory Matters (Tables)	6 Months Ended
	Jun. 30, 2017
Commitments and Contingencies Disclosure [Abstract]
Summary of lending-related and other commitments	The following is a summary of lending-related commitments. June 30, 2017 December 31, 2016 ($ in Thousands) Commitments to extend credit, excluding commitments to originate residential mortgage loans held for sale (a)(b) $ 8,063,899 $ 8,131,131 Commercial letters of credit (a) 5,839 7,923 Standby letters of credit (c) 242,144 259,632 (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 June 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 June 30, 2017 and $3 million at December 31, 2016 , as an estimate of the fair value of these financial instruments.
Summary of changes in the residential mortgage repurchase reserve	The following summarizes the changes in the mortgage repurchase reserve. Six Months Ended June 30, 2017 Year Ended December 31, 2016 ($ in Thousands) Balance at beginning of period $ 900 $ 1,197 Repurchase provision expense 109 456 Adjustments to provision expense — (750 ) Charge offs, net (18 ) (3 ) Balance at end of period $ 991 $ 900

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	6 Months Ended
	Jun. 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 June 30, 2017 and December 31, 2016 , aggregated by the level in the fair value hierarchy within which those measurements fall. Fair Value Hierarchy June 30, 2017 December 31, 2016 ($ in Thousands) Assets: Investment securities available for sale: U.S. Treasury securities Level 1 $ 1,002 $ 1,000 Residential mortgage-related securities: FNMA / FHLMC Level 2 546,525 639,930 GNMA Level 2 1,714,178 2,004,475 Private-label Level 2 1,086 1,121 GNMA commercial mortgage-related securities Level 2 1,419,872 2,028,898 Other securities (debt and equity) Level 1 1,634 1,602 Other securities (debt and equity) Level 2 3,173 3,000 Other securities (debt and equity) Level 3 — 200 Total investment securities available for sale Level 1 2,636 2,602 Total investment securities available for sale Level 2 3,684,834 4,677,424 Total investment securities available for sale Level 3 — 200 Residential loans held for sale (a) Level 2 41,620 — Interest rate-related instruments Level 2 28,105 33,671 Foreign currency exchange forwards Level 2 1,480 2,002 Interest rate lock commitments to originate residential mortgage loans held for sale Level 3 2,680 206 Forward commitments to sell residential mortgage loans Level 3 159 2,908 Commodity contracts Level 2 18,991 16,725 Purchased options (time deposit) Level 2 1,531 2,576 Liabilities: Interest rate-related instruments Level 2 $ 27,691 $ 33,188 Foreign currency exchange forwards Level 2 1,412 1,943 Commodity contracts Level 2 18,040 15,972 Written options (time deposit) Level 2 1,531 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.
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 six months ended June 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 — (275 ) Transfer out of level 3 securities (a) (200 ) — Balance June 30, 2017 $ — $ 2,839 (a) During the first quarter of 2017, the $200,000 level 3 investment security was transferred to level 2 based upon new pricing information.
Assets and Liabilities Measured on Nonrecurring Basis at Fair Value	The table below presents the Corporation’s loans held for sale, impaired loans, and mortgage servicing rights measured at fair value on a nonrecurring basis, aggregated by the level in the fair value hierarchy within which those measurements fall. Income Statement Category of Adjustment Recognized in Income ($ in Thousands) Fair Value Hierarchy Fair Value June 30, 2017 Assets: Commercial loans held for sale (a) Level 2 $ 4,772 Provision for credit losses $ — Impaired loans (c) Level 3 74,937 Provision for credit losses (d) (16,462 ) Other real estate owned Level 2 1,999 Foreclosure / OREO expense, net (621 ) Mortgage servicing rights Level 3 64,627 Mortgage banking, net (275 ) 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 June 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.
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 June 30, 2017 Mortgage servicing rights Discounted cash flow Discount rate 11% Mortgage servicing rights Discounted cash flow Constant prepayment rate 11% Impaired Loans Appraisals / Discounted cash flow Collateral / Discount factor 20%
Estimated fair values of financial instruments	Fair value estimates, methods, and assumptions are set forth below for the Corporation’s financial instruments. June 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 $ 396,677 $ 396,677 $ 446,558 $ 446,558 Interest-bearing deposits in other financial institutions Level 1 126,232 126,232 149,175 149,175 Federal funds sold and securities purchased under agreements to resell Level 1 43,000 43,000 46,500 46,500 Investment securities held to maturity Level 2 2,255,395 2,263,322 1,273,536 1,264,674 Investment securities available for sale Level 1 2,636 2,636 2,602 2,602 Investment securities available for sale Level 2 3,684,834 3,684,834 4,677,424 4,677,424 Investment securities available for sale Level 3 — — 200 200 FHLB and Federal Reserve Bank stocks Level 2 181,180 181,180 140,001 140,001 Commercial loans held for sale Level 2 4,772 4,772 12,474 12,474 Residential loans held for sale Level 2 41,620 41,620 108,010 108,010 Loans, net Level 3 20,501,968 20,377,586 19,776,381 19,680,317 Bank owned life insurance Level 2 588,440 588,440 585,290 585,290 Derivatives (trading and other assets) Level 2 50,107 50,107 54,974 54,974 Derivatives (trading and other assets) Level 3 2,839 2,839 3,114 3,114 Financial liabilities: Noninterest-bearing demand, savings, interest-bearing demand, and money market accounts Level 3 $ 19,677,850 $ 19,677,850 $ 20,282,321 $ 20,282,321 Brokered CDs and other time deposits Level 2 1,940,330 1,940,330 1,606,127 1,606,127 Short-term funding Level 2 1,402,482 1,402,482 1,092,035 1,092,035 Long-term funding Level 2 3,262,120 3,288,139 2,761,795 2,791,841 Standby letters of credit (a) Level 2 2,394 2,394 2,566 2,566 Derivatives (trading and other liabilities) Level 2 48,674 48,674 53,679 53,679 (a) The commitment on standby letters of credit was $242 million and $260 million at June 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.

Retirement Plans (Tables)

Retirement Plans (Tables)	6 Months Ended
	Jun. 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 Plans for three and six months ended June 30, 2017 and 2016 were as follows. Three Months Ended June 30, Six Months Ended June 30, 2017 2016 2017 2016 ($ in Thousands) Components of Net Periodic Benefit Cost Pension Plan: Service cost $ 1,782 $ 1,725 $ 3,563 $ 3,450 Interest cost 1,756 1,780 3,512 3,560 Expected return on plan assets (4,882 ) (5,065 ) (9,763 ) (10,130 ) Amortization of prior service cost (18 ) 12 (37 ) 25 Amortization of actuarial loss 487 483 975 965 Total net pension cost $ (875 ) $ (1,065 ) $ (1,750 ) $ (2,130 ) Postretirement Plan: Interest cost $ 24 $ 36 $ 48 $ 72 Amortization of prior service cost (19 ) — (38 ) — Total net periodic benefit cost $ 5 $ 36 $ 10 $ 72

Segment Reporting (Tables)

Segment Reporting (Tables)	6 Months Ended
	Jun. 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 Six Months Ended June 30, 2017 Net interest income $ 179,259 $ 179,059 $ 5,775 $ 364,093 Noninterest income 24,490 130,679 7,072 162,241 Total revenue 203,749 309,738 12,847 526,334 Credit provision* 23,050 10,271 (12,321 ) 21,000 Noninterest expense 76,897 241,339 31,771 350,007 Income (loss) before income taxes 103,802 58,128 (6,603 ) 155,327 Income tax expense (benefit) 34,012 20,345 (13,283 ) 41,074 Net income $ 69,790 $ 37,783 $ 6,680 $ 114,253 Return on average allocated capital (ROCET1)** 12.6 % 13.1 % 1.1 % 10.6 % Six Months Ended June 30, 2016 Net interest income $ 159,233 $ 170,574 $ 18,897 $ 348,704 Noninterest income 22,549 128,880 13,931 165,360 Total revenue 181,782 299,454 32,828 514,064 Credit provision* 27,853 12,388 (6,241 ) 34,000 Noninterest expense 71,543 243,260 33,528 348,331 Income (loss) before income taxes 82,386 43,806 5,541 131,733 Income tax expense (benefit) 27,716 15,332 (2,940 ) 40,108 Net income $ 54,670 $ 28,474 $ 8,481 $ 91,625 Return on average allocated capital (ROCET1)** 10.5 % 9.1 % 3.7 % 9.2 % Segment Balance Sheet Data ($ in Thousands) Corporate and Community, Risk Management Consolidated Average balances for YTD June 2017 Average earning assets $ 10,807,106 $ 9,321,564 $ 6,414,384 $ 26,543,054 Average loans 10,797,831 9,319,719 181,049 20,298,599 Average deposits 6,433,870 11,456,200 3,604,524 21,494,594 Average allocated capital (CET1)** $ 1,120,082 $ 582,706 $ 378,104 $ 2,080,892 Average balances for YTD June 2016 Average earning assets $ 9,924,378 $ 9,222,677 $ 6,473,156 $ 25,620,211 Average loans 9,913,591 9,221,370 147,447 19,282,408 Average deposits 5,744,533 11,215,704 3,471,729 20,431,966 Average allocated capital (CET1)** $ 1,049,431 $ 630,520 $ 224,910 $ 1,904,861 * The consolidated credit provision is equal to the actual reported provision for credit losses. ** The Federal Reserve establishes capital adequacy requirements for the Corporation, including common equity Tier 1. For segment reporting purposes, the ROCET1 reflects return on average allocated common equity Tier 1. The ROCET1 for the Risk Management and Shared Services segment and the Consolidated Total is inclusive of the annualized effect of the preferred stock dividends. Segment Income Statement Data ($ in Thousands) Corporate and Commercial Specialty Community, Consumer, and Business Risk Management and Shared Services Consolidated Total Three Months Ended June 30, 2017 Net interest income $ 89,871 $ 90,131 $ 3,817 $ 183,819 Noninterest income 12,497 65,809 4,104 82,410 Total revenue 102,368 155,940 7,921 266,229 Credit provision* 11,470 5,764 (5,234 ) 12,000 Noninterest expense 39,418 125,242 11,656 176,316 Income (loss) before income taxes 51,480 24,934 1,499 77,913 Income tax expense (benefit) 16,363 8,727 (5,160 ) 19,930 Net income $ 35,117 $ 16,207 $ 6,659 $ 57,983 Return on average allocated capital (ROCET1)** 12.5 % 11.0 % 4.5 % 10.6 % Three Months Ended June 30, 2016 Net interest income $ 80,069 $ 84,969 $ 11,679 $ 176,717 Noninterest income 10,936 65,132 6,100 82,168 Total revenue 91,005 150,101 17,779 258,885 Credit provision* 15,114 6,246 (7,360 ) 14,000 Noninterest expense 37,140 121,965 15,255 174,360 Income (loss) before income taxes 38,751 21,890 9,884 70,525 Income tax expense (benefit) 13,137 7,662 635 21,434 Net income $ 25,614 $ 14,228 $ 9,249 $ 49,091 Return on average allocated capital (ROCET1)** 9.7 % 9.0 % 13.4 % 9.9 % Segment Balance Sheet Data ($ in Thousands) Corporate and Commercial Specialty Community, Consumer, and Business Risk Management and Shared Services Consolidated Total Three Months Ended June 30, 2017 Average earning assets $ 10,853,881 $ 9,510,571 $ 6,380,103 $ 26,744,555 Average loans 10,841,858 9,508,683 171,449 20,521,990 Average deposits 6,447,190 11,574,028 3,501,931 21,523,149 Average allocated capital (CET1)** $ 1,125,494 $ 588,880 $ 385,451 $ 2,099,825 Three Months Ended June 30, 2016 Average earning assets $ 10,128,726 $ 9,325,036 $ 6,514,287 $ 25,968,049 Average loans 10,115,959 9,323,720 202,306 19,641,985 Average deposits 5,570,919 11,331,214 3,386,820 20,288,953 Average allocated capital (CET1)** $ 1,067,203 $ 633,829 $ 212,209 $ 1,913,241 * The consolidated credit provision is equal to the actual reported provision for credit losses. ** The Federal Reserve establishes capital adequacy requirements for the Corporation, including common equity Tier 1. For segment reporting purposes, the ROCET1 reflects return on average allocated common equity Tier 1. The ROCET1 for the Risk Management and Shared Services segment and the Consolidated Total is inclusive of the annualized effect of the preferred stock dividends.

Accumulated Other Comprehensi39

Accumulated Other Comprehensive Income (Loss) (Tables)	6 Months Ended
	Jun. 30, 2017
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Summary of activity in accumulated other comprehensive income (loss)	The following table summarizes the components , changes, and reclassifications out of accumulated other comprehensive income (loss). ($ in Thousands) Investments 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 before reclassifications 3,632 — 3,632 Amounts reclassified from accumulated other comprehensive income: Personnel expense — 900 900 Interest income (Amortization of net unrealized gains on available for sale securities transferred to held to maturity securities) (2,575 ) — (2,575 ) Income tax expense (406 ) (342 ) (748 ) Net other comprehensive income during period 651 558 1,209 Balance June 30, 2017 $ (19,428 ) $ (34,042 ) $ (53,470 ) Balance January 1, 2016 $ 459 $ (33,075 ) $ (32,616 ) Other comprehensive income before reclassifications 82,743 — 82,743 Amounts reclassified from accumulated other comprehensive income (loss): Investment securities gain, net (6,214 ) — (6,214 ) Personnel expense — 990 990 Interest income (Amortization of net unrealized gains on available for sale securities transferred to held to maturity securities) (3,024 ) — (3,024 ) Income tax expense (28,048 ) (378 ) (28,426 ) Net other comprehensive income during period 45,457 612 46,069 Balance June 30, 2016 $ 45,916 $ (32,463 ) $ 13,453 Investments Defined Benefit Accumulated Balance April 1, 2017 $ (22,023 ) $ (34,321 ) $ (56,344 ) Other comprehensive income before reclassifications 5,744 — 5,744 Amounts reclassified from accumulated other comprehensive income: Personnel expense — 450 450 Interest income (Amortization of net unrealized gains on available for sale securities transferred to held to maturity securities) (1,548 ) — (1,548 ) Income tax expense (1,601 ) (171 ) (1,772 ) Net other comprehensive income during period 2,595 279 2,874 Balance June 30, 2017 $ (19,428 ) $ (34,042 ) $ (53,470 ) Balance April 1, 2016 $ 34,936 $ (32,769 ) $ 2,167 Other comprehensive income before reclassifications 22,321 — 22,321 Amounts reclassified from accumulated other comprehensive income (loss): Investment securities gain, net (3,116 ) — (3,116 ) Personnel expense — 495 495 Interest income (Amortization of net unrealized gains on available for sale securities transferred to held to maturity securities) (1,452 ) — (1,452 ) Income tax expense (6,773 ) (189 ) (6,962 ) Net other comprehensive income during period 10,980 306 11,286 Balance June 30, 2016 $ 45,916 $ (32,463 ) $ 13,453

Acquisitions (Details Textuals)

Acquisitions (Details Textuals) $ in Thousands	3 Months Ended		6 Months Ended	12 Months Ended
	Mar. 31, 2017USD ($)acquisition	Mar. 31, 2016USD ($)acquisition	Jun. 30, 2017USD ($)	Dec. 31, 2016USD ($)
Business Acquisition [Line Items]
Goodwill acquired during period	$ 55	$ 3,000
Additions to finite-lived intangible assets	$ 162	$ 1,000
Number of Acquisitions | acquisition	1	2
Other Intangible Assets
Business Acquisition [Line Items]
Additions to finite-lived intangible assets			$ 162	$ 1,012

Summary of Significant Accoun41

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		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Calculations for basic and diluted earnings per common share
Net income	$ 57,983	$ 49,091	$ 114,253	$ 91,625
Preferred stock dividends	(2,339)	(2,169)	(4,669)	(4,367)
Net income available to common equity	55,644	46,922	109,584	87,258
Common shareholder dividends	(18,326)	(16,443)	(36,577)	(32,646)
Unvested share-based payment awards	(110)	(182)	(227)	(388)
Undistributed earnings	37,208	30,297	72,780	54,224
Undistributed earnings allocated to common shareholders	36,980	29,963	72,273	53,649
Undistributed earnings allocated to unvested share-based payment awards	228	334	507	575
Undistributed earnings	37,208	30,297	72,780	54,224
Basic
Distributed earnings to common shareholders	18,326	16,443	36,577	32,646
Undistributed earnings allocated to common shareholders	36,980	29,963	72,273	53,649
Total common shareholders earnings, basic	55,306	46,406	108,850	86,295
Diluted
Distributed earnings to common shareholders	18,326	16,443	36,577	32,646
Undistributed earnings allocated to common shareholders	36,980	29,963	72,273	53,649
Total common shareholders earnings, diluted	$ 55,306	$ 46,406	$ 108,850	$ 86,295
Weighted average common shares outstanding (in shares)	151,573	148,511	151,196	148,556
Effect of dilutive common stock awards (in shares)	1,958	1,019	2,155	962
Effect of dilutive common stock warrants (in shares)	771	0	796	0
Diluted weighted average common shares outstanding (in shares)	154,302	149,530	154,147	149,518
Basic earnings (loss) per common share (in usd per share)	$ 0.36	$ 0.31	$ 0.72	$ 0.58
Diluted earnings (loss) per common share (in usd per share)	$ 0.36	$ 0.31	$ 0.71	$ 0.58

Earnings Per Common Share (Text

Earnings Per Common Share (Textual) (Details) - shares	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 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		4,000,000		4,000,000
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	1,000,000	4,000,000	900,000	4,000,000

Stock-Based Compensation, Stock

Stock-Based Compensation, Stock Option Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2017	Dec. 31, 2016
Fair value assumptions of stock options
Dividend yield	2.00%	3.00%
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)	1,217,640
Forfeited or expired (in shares)	(447,751)
Stock Options Shares Outstanding, Ending balance (in shares)	5,492,010	6,357,843
Options exercisable (in shares)	3,120,596
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)	16.27
Forfeited or expired, Weighted Average Exercise Price (in usd per share)	33.58
Stock Options Outstanding, Weighted Average Exercise Price, Ending balance (in usd per share)	18.10	$ 17.67
Options Exercisable, Weighted Average Exercise Price (in usd per share)	$ 16.53
Stock Options Outstanding, Weighted Average Remaining Contractual Term	6 years 9 months 18 days	6 years 1 month 6 days
Options exercisable, Weighted Average Remaining Contractual Term	5 years 5 months 19 days
Stock Options Outstanding, Aggregate Intrinsic Value	$ 39,339	$ 47,902
Options exercisable, Aggregate Intrinsic Value	$ 27,075

Stock-Based Compensation, Restr

Stock-Based Compensation, Restricted Stock Activity (Details)	6 Months Ended
	Jun. 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	737,080
Vested (in shares) | shares	(851,381)
Forfeited (in shares) | shares	(61,616)
Outstanding Shares, Ending balance (in shares) | shares	2,201,463
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	25.58
Vested, Weighted Average Grant Date Fair Value (in usd per share) | $ / shares	17.88
Forfeited, Weighted Average Grant Date Fair Value (in usd per share) | $ / shares	18.41
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 ($) $ in Thousands	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Stock Based Compensation (Textuals) [Abstract]
Intrinsic value of stock options exercised	$ 11,000	$ 1,000
Total fair value of vested stock options	$ 4,000	$ 3,000
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
Recognized compensation expense for vesting of stock options	2,000	$ 2,000
Unvested share-based payment awards	$ 7,000
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
Recognized compensation expense for vesting of stock options	11,000	$ 11,000
Unvested share-based payment awards	$ 26,000
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	Jun. 30, 2017	Dec. 31, 2016
Investment securities available for sale:
Amortized Cost	$ 3,713,769	$ 4,724,895
Gross Unrealized Gains	15,957	19,132
Gross Unrealized Losses	(42,256)	(63,801)
Fair Value	3,687,470	4,680,226
Investment securities held to maturity:
Amortized Cost	2,255,395	1,273,536
Gross Unrealized Gains	27,208	4,523
Gross Unrealized Losses	(19,281)	(13,385)
Fair Value	2,263,322	1,264,674
US Treasury Securities
Investment securities available for sale:
Amortized Cost	1,004	1,000
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(2)	0
Fair Value	1,002	1,000
Obligations of state and political subdivisions (municipal securities)
Investment securities held to maturity:
Amortized Cost	1,162,920	1,145,843
Gross Unrealized Gains	13,766	3,868
Gross Unrealized Losses	(4,320)	(12,036)
Fair Value	1,172,366	1,137,675
Private Label
Investment securities available for sale:
Amortized Cost	1,102	1,134
Gross Unrealized Gains	0	1
Gross Unrealized Losses	(16)	(14)
Fair Value	1,086	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	1,443,501	2,064,508
Gross Unrealized Gains	74	356
Gross Unrealized Losses	(23,703)	(35,966)
Fair Value	1,419,872	2,028,898
Investment securities held to maturity:
Amortized Cost	575,383
Gross Unrealized Gains	8,964
Gross Unrealized Losses	(11,181)
Fair Value	573,166
Other Debt And Other Equity Securities
Investment securities available for sale:
Amortized Cost	4,718	4,718
Gross Unrealized Gains	116	105
Gross Unrealized Losses	(27)	(21)
Fair Value	4,807	4,802
FNMA and FHLMC | Residential Related Securities
Investment securities available for sale:
Amortized Cost	534,058	625,234
Gross Unrealized Gains	13,873	17,298
Gross Unrealized Losses	(1,406)	(2,602)
Fair Value	546,525	639,930
Investment securities held to maturity:
Amortized Cost	43,575	37,697
Gross Unrealized Gains	430	439
Gross Unrealized Losses	(566)	(693)
Fair Value	43,439	37,443
GNMA | Residential Related Securities
Investment securities available for sale:
Amortized Cost	1,729,386	2,028,301
Gross Unrealized Gains	1,894	1,372
Gross Unrealized Losses	(17,102)	(25,198)
Fair Value	1,714,178	2,004,475
Investment securities held to maturity:
Amortized Cost	473,517	89,996
Gross Unrealized Gains	4,048	216
Gross Unrealized Losses	(3,214)	(656)
Fair Value	$ 474,351	$ 89,556

Investment Securities, AFS an48

Investment Securities, AFS and HTM Contractual Maturities (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Amortized Cost
Available for Sale, Due in one year or less	$ 1,500
Available for Sale, Due after one year through five years	4,204
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	5,704
Investment securities available for sale, amortized cost	3,713,769	$ 4,724,895
Fair Value
Available for Sale, Due in one year or less	1,506
Available for Sale, Due after one year through five years	4,175
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	5,681
Investment securities available for sale, at fair value	$ 3,687,470	4,680,226
Ratio of Fair Value to Amortized Cost	99.30%
Amortized Cost
Held to Maturity, Due in one year or less	$ 41,085
Held to Maturity, Due after one year through five years	239,986
Held to Maturity, Due after five years through ten years	261,149
Held to Maturity, Due after ten years	620,700
Held to Maturity, Debt Securities, Amortized Cost Basis	1,162,920
Held to Maturity Amortized Cost	2,255,395	1,273,536
Fair Value
Held to Maturity, Due in one year or less	33,447
Held to Maturity, Due after one year through five years	246,760
Held to Maturity, Due after five years through ten years	265,255
Held to Maturity, Due after ten years	626,904
Held to Maturity, Securities, Debt Securities	1,172,366
Held to Maturity, Total debt securities	$ 2,263,322	1,264,674
Ratio of Fair Value to Amortized Cost	100.40%
Private Label
Amortized Cost
Investment securities available for sale, amortized cost	$ 1,102	1,134
Fair Value
Investment securities available for sale, at fair value	1,086	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	1,443,501	2,064,508
Fair Value
Investment securities available for sale, at fair value	1,419,872	2,028,898
Amortized Cost
Held to Maturity Amortized Cost	575,383
Fair Value
Held to Maturity, Total debt securities	573,166
Equity Securities [Member]
Amortized Cost
Investment securities available for sale, amortized cost	18
Fair Value
Investment securities available for sale, at fair value	128
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	534,058	625,234
Fair Value
Investment securities available for sale, at fair value	546,525	639,930
Amortized Cost
Held to Maturity Amortized Cost	43,575	37,697
Fair Value
Held to Maturity, Total debt securities	43,439	37,443
GNMA | Residential Related Securities
Amortized Cost
Investment securities available for sale, amortized cost	1,729,386	2,028,301
Fair Value
Investment securities available for sale, at fair value	1,714,178	2,004,475
Amortized Cost
Held to Maturity Amortized Cost	473,517	89,996
Fair Value
Held to Maturity, Total debt securities	$ 474,351	$ 89,556

Investment Securities, Gains, L

Investment Securities, Gains, Losses, and Proceeds (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2017	Jun. 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	361	0
Total gains	361	6,403
Gross losses on available for sale securities	0	(189)
Gross losses on held to maturity securities	(5)	0
Total losses	5	189
Total investment securities gains, net	356	6,214
Proceeds from sales of securities	$ 16,059	$ 359,484

Investment Securities, AFS an50

Investment Securities, AFS and HTM Securities Gross Unrealized Losses (Details) $ in Thousands	Jun. 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	$ (26,282)	$ (44,266)
Unrealized losses on available for sale securities, 12 months or more	(15,974)	(19,535)
Total unrealized losses on available for sale securities	(42,256)	(63,801)
Fair value of unrealized losses on available for sale securities, less than 12 months	2,263,149	3,397,143
Fair value of unrealized losses on available for sale securities, 12 months or more	533,477	430,377
Total fair value of unrealized losses on available for sale securities	$ 2,796,626	$ 3,827,520
Number of available for sale securities in a continuous unrealized loss position less than twelve months | security	118	145
Number of available for sale securities in a continuous unrealized loss position for twelve months or more | security	33	22
Held-to-maturity Securities Continuous Unrealized Loss Position [Abstract]
Unrealized losses on held to maturity securities, less than 12 months	$ (11,438)	$ (13,034)
Unrealized losses on held to maturity securities, 12 months or more	(7,843)	(351)
Total unrealized losses on held to maturity securities	$ (19,281)	$ (13,385)
Held-to-maturity, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions, 12 Months or Longer | security	21	5
Fair value of unrealized losses on held to maturity securities, less than 12 months	$ 908,294	$ 496,296
Fair value of unrealized losses on held to maturity securities, 12 months or more	253,102	7,783
Total fair value of unrealized losses on held to maturity securities	$ 1,161,396	$ 504,079
Held-to-maturity, Securities In Unrealized Loss Positions Qualitative Disclosure Number Of Positions, less than 12 Months | security	378	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	1,002
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	$ 1,002
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	$ (4,186)	$ (11,937)
Unrealized losses on held to maturity securities, 12 months or more	(134)	(99)
Total unrealized losses on held to maturity securities	(4,320)	(12,036)
Fair value of unrealized losses on held to maturity securities, less than 12 months	222,642	414,186
Fair value of unrealized losses on held to maturity securities, 12 months or more	4,814	1,752
Total fair value of unrealized losses on held to maturity securities	$ 227,456	$ 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	301	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	9	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	(16)	(14)
Total unrealized losses on available for sale securities	(16)	(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	1,084	1,119
Total fair value of unrealized losses on available for sale securities	$ 1,084	$ 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	$ (8,627)	$ (16,445)
Unrealized losses on available for sale securities, 12 months or more	(15,076)	(19,521)
Total unrealized losses on available for sale securities	(23,703)	(35,966)
Fair value of unrealized losses on available for sale securities, less than 12 months	850,180	1,427,889
Fair value of unrealized losses on available for sale securities, 12 months or more	496,698	429,258
Total fair value of unrealized losses on available for sale securities	$ 1,346,878	$ 1,857,147
Number of available for sale securities in a continuous unrealized loss position less than twelve months | security	54	74
Number of available for sale securities in a continuous unrealized loss position for twelve months or more | security	31	21
Held-to-maturity Securities Continuous Unrealized Loss Position [Abstract]
Unrealized losses on held to maturity securities, less than 12 months	$ (3,683)
Unrealized losses on held to maturity securities, 12 months or more	(7,498)
Total unrealized losses on held to maturity securities	(11,181)
Fair value of unrealized losses on held to maturity securities, less than 12 months	301,594
Fair value of unrealized losses on held to maturity securities, 12 months or more	241,385
Total fair value of unrealized losses on held to maturity securities	$ 542,979
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	14
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	10
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	$ (27)	$ (21)
Unrealized losses on available for sale securities, 12 months or more	0	0
Total unrealized losses on available for sale securities	(27)	(21)
Fair value of unrealized losses on available for sale securities, less than 12 months	2,173	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	$ 2,173	$ 1,479
Number of available for sale securities in a continuous unrealized loss position less than twelve months | security	3	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	$ (1,406)	$ (2,602)
Unrealized losses on available for sale securities, 12 months or more	0	0
Total unrealized losses on available for sale securities	(1,406)	(2,602)
Fair value of unrealized losses on available for sale securities, less than 12 months	223,326	244,252
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	$ 223,326	$ 244,252
Number of available for sale securities in a continuous unrealized loss position less than twelve months | security	18	14
Number of available for sale securities in a continuous unrealized loss position for twelve months or more | security	0	0
Held-to-maturity Securities Continuous Unrealized Loss Position [Abstract]
Unrealized losses on held to maturity securities, less than 12 months	$ (377)	$ (441)
Unrealized losses on held to maturity securities, 12 months or more	(189)	(252)
Total unrealized losses on held to maturity securities	(566)	(693)
Fair value of unrealized losses on held to maturity securities, less than 12 months	25,507	17,477
Fair value of unrealized losses on held to maturity securities, 12 months or more	5,657	6,031
Total fair value of unrealized losses on held to maturity securities	$ 31,164	$ 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	18	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	1	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	$ (16,220)	$ (25,198)
Unrealized losses on available for sale securities, 12 months or more	(882)	0
Total unrealized losses on available for sale securities	(17,102)	(25,198)
Fair value of unrealized losses on available for sale securities, less than 12 months	1,186,468	1,723,523
Fair value of unrealized losses on available for sale securities, 12 months or more	35,695	0
Total fair value of unrealized losses on available for sale securities	$ 1,222,163	$ 1,723,523
Number of available for sale securities in a continuous unrealized loss position less than twelve months | security	42	54
Number of available for sale securities in a continuous unrealized loss position for twelve months or more | security	1	0
Held-to-maturity Securities Continuous Unrealized Loss Position [Abstract]
Unrealized losses on held to maturity securities, less than 12 months	$ (3,192)	$ (656)
Unrealized losses on held to maturity securities, 12 months or more	(22)	0
Total unrealized losses on held to maturity securities	(3,214)	(656)
Fair value of unrealized losses on held to maturity securities, less than 12 months	358,551	64,633
Fair value of unrealized losses on held to maturity securities, 12 months or more	1,246	0
Total fair value of unrealized losses on held to maturity securities	$ 359,797	$ 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	45	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	1	0

Investment Securities (Details

Investment Securities (Details Textual) - USD ($) $ in Thousands	6 Months Ended
	Jun. 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
Held-to-maturity Securities, Sold Security, at Carrying Value	16,000
Held-to-maturity Securities, Sold Security, Realized Gain (Loss)	356
Securities pledged as collateral	2,000,000	$ 1,800,000
Federal Home Loan Bank Stock	106,000	65,000
Federal Reserve Bank Stock	$ 76,000	$ 75,000

Loans, Loan Composition (Detail

Loans, Loan Composition (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Loans and Leases Receivable Disclosure [Line Items]
Total loans	$ 20,783,069	$ 20,054,716
Commercial and industrial
Loans and Leases Receivable Disclosure [Line Items]
Total loans	6,571,000	6,489,014
Commercial real estate — owner occupied
Loans and Leases Receivable Disclosure [Line Items]
Total loans	845,336	897,724
Commercial and business lending
Loans and Leases Receivable Disclosure [Line Items]
Total loans	7,416,336	7,386,738
Commercial real estate — investor
Loans and Leases Receivable Disclosure [Line Items]
Total loans	3,329,585	3,574,732
Real estate construction
Loans and Leases Receivable Disclosure [Line Items]
Total loans	1,651,805	1,432,497
Commercial real estate lending
Loans and Leases Receivable Disclosure [Line Items]
Total loans	4,981,390	5,007,229
Total commercial
Loans and Leases Receivable Disclosure [Line Items]
Total loans	12,397,726	12,393,967
Residential mortgage
Loans and Leases Receivable Disclosure [Line Items]
Total loans	7,115,457	6,332,327
Home equity
Loans and Leases Receivable Disclosure [Line Items]
Total loans	897,111	934,443
Other consumer
Loans and Leases Receivable Disclosure [Line Items]
Total loans	372,775	393,979
Total consumer
Loans and Leases Receivable Disclosure [Line Items]
Total loans	$ 8,385,343	$ 7,660,749

Loans Loans, Loans by Credit Qu

Loans Loans, Loans by Credit Quality Indicator (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	$ 20,783,069	$ 20,054,716
Pass
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	20,133,812	19,251,353
Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	154,784	176,918
Potential Problem
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	262,585	351,142
Nonaccrual
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	231,888	275,303
Commercial and industrial
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	6,571,000	6,489,014
Commercial and industrial | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	6,183,037	5,937,119
Commercial and industrial | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	103,881	141,328
Commercial and industrial | Potential Problem
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	142,607	227,196
Commercial and industrial | Nonaccrual
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	141,475	183,371
Commercial real estate — owner occupied
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	845,336	897,724
Commercial real estate — owner occupied | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	754,446	805,871
Commercial real estate — owner occupied | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	14,366	17,785
Commercial real estate — owner occupied | Potential Problem
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	60,724	64,524
Commercial real estate — owner occupied | Nonaccrual
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	15,800	9,544
Commercial and business lending
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	7,416,336	7,386,738
Commercial and business lending | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	6,937,483	6,742,990
Commercial and business lending | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	118,247	159,113
Commercial and business lending | Potential Problem
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	203,331	291,720
Commercial and business lending | Nonaccrual
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	157,275	192,915
Commercial real estate — investor
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	3,329,585	3,574,732
Commercial real estate — investor | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	3,260,187	3,491,217
Commercial real estate — investor | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	13,623	14,236
Commercial real estate — investor | Potential Problem
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	48,569	51,228
Commercial real estate — investor | Nonaccrual
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	7,206	18,051
Real estate construction
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	1,651,805	1,432,497
Real estate construction | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	1,621,198	1,429,083
Real estate construction | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	19,989	105
Real estate construction | Potential Problem
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	8,901	2,465
Real estate construction | Nonaccrual
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	1,717	844
Commercial real estate lending
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	4,981,390	5,007,229
Commercial real estate lending | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	4,881,385	4,920,300
Commercial real estate lending | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	33,612	14,341
Commercial real estate lending | Potential Problem
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	57,470	53,693
Commercial real estate lending | Nonaccrual
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	8,923	18,895
Total commercial
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	12,397,726	12,393,967
Total commercial | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	11,818,868	11,663,290
Total commercial | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	151,859	173,454
Total commercial | Potential Problem
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	260,801	345,413
Total commercial | Nonaccrual
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	166,198	211,810
Residential mortgage
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	7,115,457	6,332,327
Residential mortgage | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	7,060,673	6,275,162
Residential mortgage | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	1,233	1,314
Residential mortgage | Potential Problem
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	1,576	5,615
Residential mortgage | Nonaccrual
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	51,975	50,236
Home equity
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	897,111	934,443
Home equity | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	882,253	919,740
Home equity | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	1,168	1,588
Home equity | Potential Problem
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	208	114
Home equity | Nonaccrual
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	13,482	13,001
Other consumer
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	372,775	393,979
Other consumer | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	372,018	393,161
Other consumer | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	524	562
Other consumer | Potential Problem
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	0	0
Other consumer | Nonaccrual
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	233	256
Total consumer
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	8,385,343	7,660,749
Total consumer | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	8,314,944	7,588,063
Total consumer | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	2,925	3,464
Total consumer | Potential Problem
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	1,784	5,729
Total consumer | Nonaccrual
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	$ 65,690	$ 63,493

Loans, Loans by Past Due Status

Loans, Loans by Past Due Status (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Summarized details of Loans
Current	$ 20,529,238	$ 19,756,523
Nonaccrual	231,888	275,303
Total loans	20,783,069	20,054,716
Accruing loans past due 90 days or more	2,000	2,000
Nonaccrual Loans, Current Portion	$ 180,000	$ 224,000
Percent of current nonaccrual loans	78.00%	81.00%
30-59 Days Past Due
Summarized details of Loans
Total Past Due	$ 17,148	$ 16,662
60-89 Days Past Due
Summarized details of Loans
Total Past Due	3,260	4,615
90 Days or More Past Due
Summarized details of Loans
Total Past Due	1,535	1,613
Commercial and industrial
Summarized details of Loans
Current	6,428,022	6,303,994
Nonaccrual	141,475	183,371
Total loans	6,571,000	6,489,014
Commercial and industrial | 30-59 Days Past Due
Summarized details of Loans
Total Past Due	1,042	965
Commercial and industrial | 60-89 Days Past Due
Summarized details of Loans
Total Past Due	213	448
Commercial and industrial | 90 Days or More Past Due
Summarized details of Loans
Total Past Due	248	236
Commercial real estate — owner occupied
Summarized details of Loans
Current	828,252	886,796
Nonaccrual	15,800	9,544
Total loans	845,336	897,724
Commercial real estate — owner occupied | 30-59 Days Past Due
Summarized details of Loans
Total Past Due	1,136	968
Commercial real estate — owner occupied | 60-89 Days Past Due
Summarized details of Loans
Total Past Due	148	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	7,256,274	7,190,790
Nonaccrual	157,275	192,915
Total loans	7,416,336	7,386,738
Commercial and business lending | 30-59 Days Past Due
Summarized details of Loans
Total Past Due	2,178	1,933
Commercial and business lending | 60-89 Days Past Due
Summarized details of Loans
Total Past Due	361	864
Commercial and business lending | 90 Days or More Past Due
Summarized details of Loans
Total Past Due	248	236
Commercial real estate — investor
Summarized details of Loans
Current	3,321,480	3,555,750
Nonaccrual	7,206	18,051
Total loans	3,329,585	3,574,732
Commercial real estate — investor | 30-59 Days Past Due
Summarized details of Loans
Total Past Due	899	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	1,649,953	1,431,284
Nonaccrual	1,717	844
Total loans	1,651,805	1,432,497
Real estate construction | 30-59 Days Past Due
Summarized details of Loans
Total Past Due	40	264
Real estate construction | 60-89 Days Past Due
Summarized details of Loans
Total Past Due	95	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	4,971,433	4,987,034
Nonaccrual	8,923	18,895
Total loans	4,981,390	5,007,229
Commercial real estate lending | 30-59 Days Past Due
Summarized details of Loans
Total Past Due	939	695
Commercial real estate lending | 60-89 Days Past Due
Summarized details of Loans
Total Past Due	95	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	12,227,707	12,177,824
Nonaccrual	166,198	211,810
Total loans	12,397,726	12,393,967
Total commercial | 30-59 Days Past Due
Summarized details of Loans
Total Past Due	3,117	2,628
Total commercial | 60-89 Days Past Due
Summarized details of Loans
Total Past Due	456	1,469
Total commercial | 90 Days or More Past Due
Summarized details of Loans
Total Past Due	248	236
Residential mortgage
Summarized details of Loans
Current	7,054,317	6,273,949
Nonaccrual	51,975	50,236
Total loans	7,115,457	6,332,327
Residential mortgage | 30-59 Days Past Due
Summarized details of Loans
Total Past Due	8,163	7,298
Residential mortgage | 60-89 Days Past Due
Summarized details of Loans
Total Past Due	1,002	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	877,705	915,593
Nonaccrual	13,482	13,001
Total loans	897,111	934,443
Home equity | 30-59 Days Past Due
Summarized details of Loans
Total Past Due	4,755	4,265
Home equity | 60-89 Days Past Due
Summarized details of Loans
Total Past Due	1,169	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	369,509	389,157
Nonaccrual	233	256
Total loans	372,775	393,979
Other consumer | 30-59 Days Past Due
Summarized details of Loans
Total Past Due	1,113	2,471
Other consumer | 60-89 Days Past Due
Summarized details of Loans
Total Past Due	633	718
Other consumer | 90 Days or More Past Due
Summarized details of Loans
Total Past Due	1,287	1,377
Total consumer
Summarized details of Loans
Current	8,301,531	7,578,699
Nonaccrual	65,690	63,493
Total loans	8,385,343	7,660,749
Total consumer | 30-59 Days Past Due
Summarized details of Loans
Total Past Due	14,031	14,034
Total consumer | 60-89 Days Past Due
Summarized details of Loans
Total Past Due	2,804	3,146
Total consumer | 90 Days or More Past Due
Summarized details of Loans
Total Past Due	$ 1,287	$ 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	6 Months Ended	12 Months Ended
	Jun. 30, 2017	Dec. 31, 2016
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	$ 309,213	$ 355,160
Unpaid Principal Balance	349,590	394,588
Related Allowance	39,988	46,483
Average Recorded Investment	336,528	378,277
Interest Income Recognized	$ 3,480	$ 10,228
Net Recorded Investment of the Impaired Loans	77.00%	78.00%
Loans with a related allowance
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	$ 196,914	$ 221,012
Unpaid Principal Balance	211,096	236,876
Related Allowance	39,988	46,483
Average Recorded Investment	202,339	237,729
Interest Income Recognized	3,157	8,383
Loans with no related allowance
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	112,299	134,148
Unpaid Principal Balance	138,494	157,712
Related Allowance	0	0
Average Recorded Investment	134,189	140,548
Interest Income Recognized	323	1,845
Commercial and industrial
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	173,015	215,255
Unpaid Principal Balance	201,702	242,676
Related Allowance	17,882	21,617
Average Recorded Investment	200,194	229,191
Interest Income Recognized	808	4,031
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	89,563	101,770
Unpaid Principal Balance	94,231	107,813
Related Allowance	17,882	21,617
Average Recorded Investment	95,205	111,211
Interest Income Recognized	635	2,512
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	83,452	113,485
Unpaid Principal Balance	107,471	134,863
Related Allowance	0	0
Average Recorded Investment	104,989	117,980
Interest Income Recognized	173	1,519
Commercial real estate — owner occupied
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	19,945	15,034
Unpaid Principal Balance	22,700	17,907
Related Allowance	526	295
Average Recorded Investment	18,992	15,870
Interest Income Recognized	142	412
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	7,249	6,595
Unpaid Principal Balance	9,154	8,641
Related Allowance	526	295
Average Recorded Investment	6,086	7,111
Interest Income Recognized	93	274
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	12,696	8,439
Unpaid Principal Balance	13,546	9,266
Related Allowance	0	0
Average Recorded Investment	12,906	8,759
Interest Income Recognized	49	138
Commercial and business lending
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	192,960	230,289
Unpaid Principal Balance	224,402	260,583
Related Allowance	18,408	21,912
Average Recorded Investment	219,186	245,061
Interest Income Recognized	950	4,443
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	96,812	108,365
Unpaid Principal Balance	103,385	116,454
Related Allowance	18,408	21,912
Average Recorded Investment	101,291	118,322
Interest Income Recognized	728	2,786
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	96,148	121,924
Unpaid Principal Balance	121,017	144,129
Related Allowance	0	0
Average Recorded Investment	117,895	126,739
Interest Income Recognized	222	1,657
Commercial real estate — investor
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	21,834	33,340
Unpaid Principal Balance	22,577	34,155
Related Allowance	330	3,541
Average Recorded Investment	21,853	38,234
Interest Income Recognized	767	2,124
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	15,832	27,196
Unpaid Principal Balance	16,111	27,677
Related Allowance	330	3,541
Average Recorded Investment	15,782	31,142
Interest Income Recognized	767	2,124
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	6,002	6,144
Unpaid Principal Balance	6,466	6,478
Related Allowance	0	0
Average Recorded Investment	6,071	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	2,038	1,203
Unpaid Principal Balance	2,410	1,566
Related Allowance	707	441
Average Recorded Investment	2,090	1,321
Interest Income Recognized	54	67
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	1,819	1,203
Unpaid Principal Balance	2,188	1,566
Related Allowance	707	441
Average Recorded Investment	1,868	1,321
Interest Income Recognized	54	67
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	219	0
Unpaid Principal Balance	222	0
Related Allowance	0	0
Average Recorded Investment	222	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	23,872	34,543
Unpaid Principal Balance	24,987	35,721
Related Allowance	1,037	3,982
Average Recorded Investment	23,943	39,555
Interest Income Recognized	821	2,191
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	17,651	28,399
Unpaid Principal Balance	18,299	29,243
Related Allowance	1,037	3,982
Average Recorded Investment	17,650	32,463
Interest Income Recognized	821	2,191
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	6,221	6,144
Unpaid Principal Balance	6,688	6,478
Related Allowance	0	0
Average Recorded Investment	6,293	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	216,832	264,832
Unpaid Principal Balance	249,389	296,304
Related Allowance	19,445	25,894
Average Recorded Investment	243,129	284,616
Interest Income Recognized	1,771	6,634
Total commercial | Loans with a related allowance
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	114,463	136,764
Unpaid Principal Balance	121,684	145,697
Related Allowance	19,445	25,894
Average Recorded Investment	118,941	150,785
Interest Income Recognized	1,549	4,977
Total commercial | Loans with no related allowance
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	102,369	128,068
Unpaid Principal Balance	127,705	150,607
Related Allowance	0	0
Average Recorded Investment	124,188	133,831
Interest Income Recognized	222	1,657
Residential mortgage
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	69,599	68,336
Unpaid Principal Balance	75,409	74,088
Related Allowance	10,649	11,091
Average Recorded Investment	70,292	70,435
Interest Income Recognized	1,213	2,447
Residential mortgage | Loans with a related allowance
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	60,209	62,362
Unpaid Principal Balance	65,163	67,090
Related Allowance	10,649	11,091
Average Recorded Investment	60,831	63,825
Interest Income Recognized	1,112	2,263
Residential mortgage | Loans with no related allowance
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	9,390	5,974
Unpaid Principal Balance	10,246	6,998
Related Allowance	0	0
Average Recorded Investment	9,461	6,610
Interest Income Recognized	101	184
Home equity
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	21,467	20,757
Unpaid Principal Balance	23,450	22,912
Related Allowance	9,665	9,312
Average Recorded Investment	21,772	21,932
Interest Income Recognized	484	1,118
Home equity | Loans with a related allowance
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	20,927	20,651
Unpaid Principal Balance	22,907	22,805
Related Allowance	9,665	9,312
Average Recorded Investment	21,232	21,825
Interest Income Recognized	484	1,114
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	1,315	1,235
Unpaid Principal Balance	1,342	1,284
Related Allowance	229	186
Average Recorded Investment	1,335	1,294
Interest Income Recognized	12	29
Other consumer | Loans with a related allowance
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	1,315	1,235
Unpaid Principal Balance	1,342	1,284
Related Allowance	229	186
Average Recorded Investment	1,335	1,294
Interest Income Recognized	12	29
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	92,381	90,328
Unpaid Principal Balance	100,201	98,284
Related Allowance	20,543	20,589
Average Recorded Investment	93,399	93,661
Interest Income Recognized	1,709	3,594
Total consumer | Loans with a related allowance
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	82,451	84,248
Unpaid Principal Balance	89,412	91,179
Related Allowance	20,543	20,589
Average Recorded Investment	83,398	86,944
Interest Income Recognized	1,608	3,406
Total consumer | Loans with no related allowance
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	9,930	6,080
Unpaid Principal Balance	10,789	7,105
Related Allowance	0	0
Average Recorded Investment	10,001	6,717
Interest Income Recognized	$ 101	$ 188

Loans, Troubled Debt Restructur

Loans, Troubled Debt Restructurings Performing and Nonaccrual (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Financing Receivable, Modifications [Line Items]
Performing Restructured Loans	$ 77,325	$ 79,857
Nonaccrual Restructured Loans	51,715	29,385
Commercial and industrial
Financing Receivable, Modifications [Line Items]
Performing Restructured Loans	31,540	31,884
Nonaccrual Restructured Loans	27,016	1,276
Commercial real estate — owner occupied
Financing Receivable, Modifications [Line Items]
Performing Restructured Loans	4,145	5,490
Nonaccrual Restructured Loans	2,145	2,220
Commercial real estate — investor
Financing Receivable, Modifications [Line Items]
Performing Restructured Loans	14,628	15,289
Nonaccrual Restructured Loans	602	924
Real estate construction
Financing Receivable, Modifications [Line Items]
Performing Restructured Loans	321	359
Nonaccrual Restructured Loans	164	150
Residential mortgage
Financing Receivable, Modifications [Line Items]
Performing Restructured Loans	17,624	18,100
Nonaccrual Restructured Loans	19,365	21,906
Home equity
Financing Receivable, Modifications [Line Items]
Performing Restructured Loans	7,985	7,756
Nonaccrual Restructured Loans	2,401	2,877
Other consumer
Financing Receivable, Modifications [Line Items]
Performing Restructured Loans	1,082	979
Nonaccrual Restructured Loans	$ 22	$ 32

Loans, Loans Modified in a Trou

Loans, Loans Modified in a Troubled Debt Restructuring (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2017USD ($)loan	Jun. 30, 2016USD ($)loan
Financing Receivable, Modifications [Line Items]
Number of Loans | loan	88	97
Recorded Investment	$ 35,020	$ 8,103
Unpaid Principal Balance	$ 56,700	$ 8,527
Commercial and industrial
Financing Receivable, Modifications [Line Items]
Number of Loans | loan	24	11
Recorded Investment	$ 30,935	$ 2,608
Unpaid Principal Balance	$ 52,260	$ 2,676
Commercial real estate — owner occupied
Financing Receivable, Modifications [Line Items]
Number of Loans | loan	2	1
Recorded Investment	$ 716	$ 120
Unpaid Principal Balance	$ 716	$ 126
Residential mortgage
Financing Receivable, Modifications [Line Items]
Number of Loans | loan	36	48
Recorded Investment	$ 2,695	$ 3,942
Unpaid Principal Balance	$ 2,805	$ 4,171
Home equity
Financing Receivable, Modifications [Line Items]
Number of Loans | loan	26	37
Recorded Investment	$ 674	$ 1,433
Unpaid Principal Balance	$ 919	$ 1,554

Loans, Troubled Debt Restruct58

Loans, Troubled Debt Restructurings Subsequent Default (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2017USD ($)loan	Jun. 30, 2016USD ($)loan
Financing Receivable, Modifications [Line Items]
Number of Loans | loan	26	38
Recorded Investment | $	$ 1,212	$ 2,739
Commercial real estate — owner occupied
Financing Receivable, Modifications [Line Items]
Number of Loans | loan	0	2
Recorded Investment | $	$ 0	$ 168
Residential mortgage
Financing Receivable, Modifications [Line Items]
Number of Loans | loan	17	25
Recorded Investment | $	$ 941	$ 2,407
Home equity
Financing Receivable, Modifications [Line Items]
Number of Loans | loan	9	11
Recorded Investment | $	$ 271	$ 164

Loans, Changes in the Allowance

Loans, Changes in the Allowance for Loan Losses by Portfolio Segment (Details) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2017	Dec. 31, 2016
Changes in the allowance for loan losses by portfolio segment
Balance at beginning of year	$ 278,335	$ 274,264
Charge offs	(27,230)	(86,439)
Recoveries	8,996	21,510
Net charge offs	(18,234)	(64,929)
Provision for loan losses	21,000	69,000
Balance at end of period	281,101	278,335
Allowance for loan losses:
Individually evaluated	17,826	24,103
Collectively evaluated	22,162	22,380
Total impaired loans	39,988	46,483
Collectively evaluated	241,113	231,852
Balance at end of period	281,101	278,335
Loans:
Individually evaluated	174,086	214,409
Collectively evaluated	135,127	140,751
Total impaired loans	309,213	355,160
Collectively evaluated	20,473,856	19,699,556
Total loans	20,783,069	20,054,716
Commercial and industrial
Changes in the allowance for loan losses by portfolio segment
Balance at beginning of year	140,126	129,959
Charge offs	(21,912)	(71,016)
Recoveries	6,498	14,543
Net charge offs	(15,414)	(56,473)
Provision for loan losses	18,295	66,640
Balance at end of period	143,007	140,126
Allowance for loan losses:
Individually evaluated	17,350	20,836
Collectively evaluated	532	781
Total impaired loans	17,882	21,617
Collectively evaluated	125,125	118,509
Balance at end of period	143,007	140,126
Loans:
Individually evaluated	140,061	180,965
Collectively evaluated	32,954	34,290
Total impaired loans	173,015	215,255
Collectively evaluated	6,397,985	6,273,759
Total loans	6,571,000	6,489,014
Commercial real estate — owner occupied
Changes in the allowance for loan losses by portfolio segment
Balance at beginning of year	14,034	18,680
Charge offs	(83)	(512)
Recoveries	145	74
Net charge offs	62	(438)
Provision for loan losses	(5,551)	(4,208)
Balance at end of period	8,545	14,034
Allowance for loan losses:
Individually evaluated	187	0
Collectively evaluated	339	295
Total impaired loans	526	295
Collectively evaluated	8,019	13,739
Balance at end of period	8,545	14,034
Loans:
Individually evaluated	15,303	8,439
Collectively evaluated	4,642	6,595
Total impaired loans	19,945	15,034
Collectively evaluated	825,391	882,690
Total loans	845,336	897,724
Commercial real estate — investor
Changes in the allowance for loan losses by portfolio segment
Balance at beginning of year	45,285	43,018
Charge offs	(803)	(1,504)
Recoveries	163	1,624
Net charge offs	(640)	120
Provision for loan losses	(3,155)	2,147
Balance at end of period	41,490	45,285
Allowance for loan losses:
Individually evaluated	183	3,117
Collectively evaluated	147	424
Total impaired loans	330	3,541
Collectively evaluated	41,160	41,744
Balance at end of period	41,490	45,285
Loans:
Individually evaluated	6,799	17,322
Collectively evaluated	15,035	16,018
Total impaired loans	21,834	33,340
Collectively evaluated	3,307,751	3,541,392
Total loans	3,329,585	3,574,732
Real estate construction
Changes in the allowance for loan losses by portfolio segment
Balance at beginning of year	26,932	25,266
Charge offs	(62)	(558)
Recoveries	47	203
Net charge offs	(15)	(355)
Provision for loan losses	4,571	2,021
Balance at end of period	31,488	26,932
Allowance for loan losses:
Individually evaluated	0	0
Collectively evaluated	707	441
Total impaired loans	707	441
Collectively evaluated	30,781	26,491
Balance at end of period	31,488	26,932
Loans:
Individually evaluated	220	0
Collectively evaluated	1,818	1,203
Total impaired loans	2,038	1,203
Collectively evaluated	1,649,767	1,431,294
Total loans	1,651,805	1,432,497
Residential mortgage
Changes in the allowance for loan losses by portfolio segment
Balance at beginning of year	27,046	28,261
Charge offs	(1,034)	(4,332)
Recoveries	342	755
Net charge offs	(692)	(3,577)
Provision for loan losses	5,212	2,362
Balance at end of period	31,566	27,046
Allowance for loan losses:
Individually evaluated	106	147
Collectively evaluated	10,543	10,944
Total impaired loans	10,649	11,091
Collectively evaluated	20,917	15,955
Balance at end of period	31,566	27,046
Loans:
Individually evaluated	11,060	7,033
Collectively evaluated	58,539	61,303
Total impaired loans	69,599	68,336
Collectively evaluated	7,045,858	6,263,991
Total loans	7,115,457	6,332,327
Home equity
Changes in the allowance for loan losses by portfolio segment
Balance at beginning of year	20,364	23,555
Charge offs	(1,196)	(4,686)
Recoveries	1,423	3,491
Net charge offs	227	(1,195)
Provision for loan losses	(351)	(1,996)
Balance at end of period	20,240	20,364
Allowance for loan losses:
Individually evaluated	0	3
Collectively evaluated	9,665	9,309
Total impaired loans	9,665	9,312
Collectively evaluated	10,575	11,052
Balance at end of period	20,240	20,364
Loans:
Individually evaluated	643	650
Collectively evaluated	20,824	20,107
Total impaired loans	21,467	20,757
Collectively evaluated	875,644	913,686
Total loans	897,111	934,443
Other consumer
Changes in the allowance for loan losses by portfolio segment
Balance at beginning of year	4,548	5,525
Charge offs	(2,140)	(3,831)
Recoveries	378	820
Net charge offs	(1,762)	(3,011)
Provision for loan losses	1,979	2,034
Balance at end of period	4,765	4,548
Allowance for loan losses:
Individually evaluated	0	0
Collectively evaluated	229	186
Total impaired loans	229	186
Collectively evaluated	4,536	4,362
Balance at end of period	4,765	4,548
Loans:
Individually evaluated	0	0
Collectively evaluated	1,315	1,235
Total impaired loans	1,315	1,235
Collectively evaluated	371,460	392,744
Total loans	$ 372,775	$ 393,979

Loans, Changes in the Allowan60

Loans, Changes in the Allowance for Loan Losses (Details) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2017	Dec. 31, 2016
Change in the allowance for unfunded commitments
Balance at beginning of period	$ 25,000
Balance at end of period	25,000	$ 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	0	1,000
Balance at end of period	$ 25,400	$ 25,400

Loans (Details Textuals)

Loans (Details Textuals) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Receivables [Abstract]
Financing Receivable, Modifications, Post-Modification Recorded Investment	$ 35,020	$ 8,103
Restructured Loans Subsequently Accruing	6,000
Ytd Restructured Loans Still On Nonaccrual	$ 29,000

Goodwill and Other Intangible62

Goodwill and Other Intangible Assets, Summary of Core Deposit and Other Intangibles (Details) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended		12 Months Ended
	Jun. 30, 2017	Mar. 31, 2017	Jun. 30, 2016	Mar. 31, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Summary of core deposit intangibles and other intangibles
Additions during the period		$ 162		$ 1,000
Amortization of other intangible assets	$ 496		$ 539		$ 1,009	$ 1,043
Core Deposit Intangibles
Summary of core deposit intangibles and other intangibles
Gross carrying amount	4,385				4,385		$ 4,385
Accumulated amortization	(4,385)				(4,385)		(4,273)
Total Estimated Amortization Expense	0				0		112
Amortization of other intangible assets					112		281
Other Intangible Assets
Summary of core deposit intangibles and other intangibles
Gross carrying amount	32,572				32,572		32,410
Accumulated amortization	(18,042)				(18,042)		(17,145)
Total Estimated Amortization Expense	$ 14,530				14,530		15,265
Additions during the period					162		1,012
Amortization of other intangible assets					$ 897		$ 1,812

Goodwill and Other Intangible63

Goodwill and Other Intangible Assets, Mortgage Servicing Rights Roll-Forward (Details) - USD ($) $ in Thousands		6 Months Ended	12 Months Ended
		Jun. 30, 2017	Dec. 31, 2016
Mortgage servicing rights:
Mortgage servicing rights at beginning of period		$ 62,085	$ 62,150
Additions		3,278	12,262
Amortization		(5,084)	(12,327)
Mortgage servicing rights at end of period		60,279	62,085
Valuation Allowance for Impairment of Recognized Servicing Assets [Roll Forward]
Valuation allowance at beginning of period		(609)	(809)
(Additions) recoveries, net		(275)	200
Valuation allowance at end of period		(884)	(609)
Mortgage servicing rights, net		59,395	61,476
Fair value of mortgage servicing rights		64,627	73,149
Portfolio of residential mortgage loans serviced for others (“servicing portfolio”)		$ 7,768,374	$ 7,974,742
Mortgage servicing rights, net to servicing portfolio		0.76%	0.77%
Mortgage servicing rights expense	[1]	$ 5,359	$ 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	Jun. 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
Six months ending December 31, 2017	901
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	14,530	$ 15,265
Mortgage Servicing Rights
Estimated future amortization expense
Six months ending December 31, 2017	5,046
Year ending December 31, 2018	8,897
Year ending December 31, 2019	7,476
Year ending December 31, 2020	6,292
Year ending December 31, 2021	5,315
Year ending December 31, 2022	4,515
Beyond 2,022	22,738
Total Estimated Amortization Expense	$ 60,279

Goodwill and Other Intangible65

Goodwill and Other Intangible Assets (Details Textuals)	3 Months Ended		6 Months Ended	12 Months Ended
	Mar. 31, 2017USD ($)acquisition	Mar. 31, 2016USD ($)acquisition	Jun. 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	Jun. 30, 2017	Dec. 31, 2016
Short-term Funding [Abstract]
Federal funds purchased	$ 345,350	$ 208,150
Securities sold under agreements to repurchase	262,319	300,197
Federal funds purchased and securities sold under agreements to repurchase	607,669	508,347
FHLB advances	697,000	482,000
Commercial paper	97,813	101,688
Other short-term funding	794,813	583,688
Total short-term funding	1,402,482	1,092,035
Long-term Funding
FHLB advances	2,765,176	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	(3,056)	(3,393)
Total long-term funding	3,262,120	2,761,795
Total short and long-term funding	$ 4,664,602	$ 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	Jun. 30, 2017	Dec. 31, 2016
RemainingContractualMaturityoftheSecuritiesSoldUnderAgreementtoRepurchase [Line Items]
Repurchase agreements	$ 262,319	$ 300,197
Overnight and Continuous
RemainingContractualMaturityoftheSecuritiesSoldUnderAgreementtoRepurchase [Line Items]
Repurchase agreements	262,319	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	262,319	300,197
Agency mortgage-related securities | Overnight and Continuous
RemainingContractualMaturityoftheSecuritiesSoldUnderAgreementtoRepurchase [Line Items]
Repurchase agreements	262,319	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	Jun. 30, 2017	Dec. 31, 2016
Subordinated Borrowing [Line Items]
Carrying Value of Securities Purchased under Agreements to Resell and Deposits Paid for Securities Borrowed		$ 381
Federal Home Loan Bank, Advances, Weighted Average Interest Rate		0.98%	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	Jun. 30, 2017	Dec. 31, 2016
Trading assets | Interest rate-related instruments — customer and mirror
Derivative Instruments Not Designated as Hedging Instruments [Abstract]
Notional Amount	$ 2,118,409	$ 2,039,323
Fair Value	28,105	33,671
Trading assets | Foreign currency exchange forwards
Derivative Instruments Not Designated as Hedging Instruments [Abstract]
Notional Amount	93,300	109,675
Fair Value	1,480	2,002
Trading assets | Commodity contracts
Derivative Instruments Not Designated as Hedging Instruments [Abstract]
Notional Amount	304,554	127,582
Fair Value	18,991	16,725
Trading liabilities | Interest rate-related instruments — customer and mirror
Derivative Instruments Not Designated as Hedging Instruments [Abstract]
Notional Amount	2,118,409	2,039,323
Fair Value	(27,691)	(33,188)
Trading liabilities | Foreign currency exchange forwards
Derivative Instruments Not Designated as Hedging Instruments [Abstract]
Notional Amount	92,969	106,251
Fair Value	(1,412)	(1,943)
Trading liabilities | Commodity contracts
Derivative Instruments Not Designated as Hedging Instruments [Abstract]
Notional Amount	303,790	128,368
Fair Value	(18,040)	(15,972)
Other assets | Interest rate lock commitments (mortgage)
Derivative Instruments Not Designated as Hedging Instruments [Abstract]
Notional Amount	356,798	285,345
Fair Value	2,680	206
Other assets | Forward commitments (mortgage)
Derivative Instruments Not Designated as Hedging Instruments [Abstract]
Notional Amount	151,500	179,600
Fair Value	159	2,908
Other assets | Purchased options (time deposit)
Derivative Instruments Not Designated as Hedging Instruments [Abstract]
Notional Amount	75,899	80,554
Fair Value	1,531	2,576
Other liabilities | Written options (time deposit)
Derivative Instruments Not Designated as Hedging Instruments [Abstract]
Notional Amount	75,899	80,554
Fair Value	$ (1,531)	$ (2,576)

Derivative and Hedging Activi70

Derivative and Hedging Activities, Income Statement Category of the Gains and Losses (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2017	Jun. 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	$ (69)	$ (1,426)
Capital market fees, net | Foreign currency exchange forwards
Gain (loss) on derivative instruments not designated as hedging instruments
Gain / (Loss) Recognized in Income	9	(48)
Capital market fees, net | Commodity contracts
Gain (loss) on derivative instruments not designated as hedging instruments
Gain / (Loss) Recognized in Income	198	358
Mortgage banking, net | Interest rate lock commitments (mortgage)
Gain (loss) on derivative instruments not designated as hedging instruments
Gain / (Loss) Recognized in Income	2,474	3,312
Mortgage banking, net | Forward commitments (mortgage)
Gain (loss) on derivative instruments not designated as hedging instruments
Gain / (Loss) Recognized in Income	$ (2,749)	$ (4,608)

Derivative and Hedging Activi71

Derivative and Hedging Activities (Details Textuals) - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Investment securities and cash equivalents pledged as collateral	$ 22	$ 40
Derivative collateral right to reclaim cash	$ 1	$ 0

Balance Sheet Offsetting (Detai

Balance Sheet Offsetting (Details) - Interest and commodity agreements - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	$ 24,322	$ 18,031
Gross amounts offset in the balance sheet	0	0
Net amounts presented in the balance sheet	24,322	18,031
Financial instruments	(16,517)	(18,031)
Collateral	(7,805)	0
Net amount	0	0
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	16,517	31,075
Gross amounts offset in the balance sheet	0	0
Net amounts presented in the balance sheet	16,517	31,075
Financial instruments	(16,517)	(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	Jun. 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	8,063,899	8,131,131
Commercial Letters Of Credit
Summary of lending-related and other commitments
Lending related commitments	5,839	7,923
Standby Letters of Credit
Summary of lending-related and other commitments
Lending related commitments	242,144	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	6 Months Ended	12 Months Ended
	Jun. 30, 2017	Dec. 31, 2016
Residential mortgage repurchase reserve
Balance at beginning of period	$ 25,000
Balance at end of period	25,000	$ 25,000
Mortgage Repurchase Reserve
Residential mortgage repurchase reserve
Balance at beginning of period	900	1,197
Repurchase provision expense	109	456
Adjustments to provision expense	0	(750)
Charge offs, net	(18)	(3)
Balance at end of period	$ 991	$ 900

Commitments, Off-Balance Shee75

Commitments, Off-Balance Sheet Arrangements, Legal Proceedings and Regulatory Matters (Details Textuals) $ in Thousands	Jan. 11, 2016USD ($)complaint	May 22, 2015USD ($)branchloan_production_office	Jun. 30, 2017USD ($)	Dec. 31, 2016USD ($)
Commitments, Off-Balance Sheet Arrangements, and Contingent Liabilities (Textuals) [Line Items]
unfunded commitments			$ 25,000	$ 25,000
Carrying value of investments			114,000	85,000
Commitments under unconsolidated projects			84,000	69,000
Number of complaints filed under legal proceedings | complaint	2
Commitment term		3 years
Mortgage loan commitment		$ 196,000
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			367	2,000
Loans sold to outside investors original amount			9,500,000
Loans sold to outside investors remaining outstanding amount			6,100,000
Residential mortgage loans sold with recourse risk			74,000	62,000
Residential mortgage loans sold with credit recourse risk			$ 85,000	$ 98,000
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
Damages sought, cash	4,000
American Funds Service Company v Associated Bank [Member]
Commitments, Off-Balance Sheet Arrangements, and Contingent Liabilities (Textuals) [Line Items]
Damages sought	$ 600

Fair Value Measurements, Assets

Fair Value Measurements, Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Investment securities available for sale:
Investment securities available for sale	$ 3,687,470	$ 4,680,226
Trading assets	48,576	52,398
Liabilities, Fair Value Disclosure [Abstract]
Trading liabilities	47,143	51,103
Fair Value, Inputs, Level 1
Investment securities available for sale:
Investment securities available for sale	2,636	2,602
Fair Value, Inputs, Level 2
Investment securities available for sale:
Investment securities available for sale	3,684,834	4,677,424
Trading assets	50,107	54,974
Liabilities, Fair Value Disclosure [Abstract]
Trading liabilities	48,674	53,679
Fair Value, Inputs, Level 3
Investment securities available for sale:
Investment securities available for sale	0	200
Trading assets	2,839	3,114
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 1 | US Treasury Securities
Investment securities available for sale:
Investment securities available for sale	1,002	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	1,634	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	2,636	2,602
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 2 | FNMA / FHLMC
Investment securities available for sale:
Investment securities available for sale	546,525	639,930
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 2 | GNMA
Investment securities available for sale:
Investment securities available for sale	1,714,178	2,004,475
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 2 | Private Label
Investment securities available for sale:
Investment securities available for sale	1,086	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	1,419,872	2,028,898
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	3,173	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	3,684,834	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	41,620	0
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 2 | Interest rate-related instruments — customer and mirror
Investment securities available for sale:
Trading assets	28,105	33,671
Liabilities, Fair Value Disclosure [Abstract]
Trading liabilities	27,691	33,188
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 2 | Foreign currency exchange forwards
Investment securities available for sale:
Trading assets	1,480	2,002
Liabilities, Fair Value Disclosure [Abstract]
Trading liabilities	1,412	1,943
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 2 | Commodity contracts
Investment securities available for sale:
Trading assets	18,991	16,725
Liabilities, Fair Value Disclosure [Abstract]
Trading liabilities	18,040	15,972
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 2 | Purchased options (time deposit)
Investment securities available for sale:
Trading assets	1,531	2,576
Liabilities, Fair Value Disclosure [Abstract]
Trading liabilities	1,531	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	2,680	206
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 3 | Forward commitments (mortgage)
Investment securities available for sale:
Trading assets	$ 159	$ 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		6 Months Ended	12 Months Ended
		Jun. 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		(275)	1,753
Ending Balance		$ 2,839	$ 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	6 Months Ended		12 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Assets and Liabilities Measured at Fair Value on a Non-recurring Basis
Mortgage servicing rights	$ 59,395		$ 61,476
Mortgage Servicing Rights (MSR) Impairment (Recovery)	275	$ 2,120
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	4,772		12,474
Residential Held-for-sale, Fair Value Disclosure	41,620		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	4,772		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	1,999		9,752
Foreclosure / OREO expense, net	(621)		(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	74,937		79,270
Provision for Credit Losses, Impaired Loans	(16,462)		(75,194)
Mortgage servicing rights	64,627		73,149
Mortgage Servicing Rights (MSR) Impairment (Recovery)	$ (275)		$ 200

Fair Value Measurements Fair Va

Fair Value Measurements Fair Value Unobservable Level 3 Measurements (Details) - Fair Value, Inputs, Level 3	6 Months Ended
	Jun. 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	11.00%
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	20.00%

Fair Value Measurements, Fair V

Fair Value Measurements, Fair Value of Financial Instruments (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Financial assets
Cash and due from banks	$ 396,677	$ 446,558
Interest-bearing deposits in other financial institutions	126,232	149,175
Federal funds sold and securities purchased under agreements to resell	43,000	46,500
Investment securities held to maturity	2,255,395	1,273,536
Investment securities held to maturity, fair value	2,263,322	1,264,674
Investment securities available for sale	3,687,470	4,680,226
FHLB and Federal Reserve Bank stocks	181,180	140,001
Commercial loans held for sale	4,772	12,474
Loans, net	20,501,968	19,776,381
Derivatives (trading and other assets)	48,576	52,398
Financial liabilities
Short-term funding	1,402,482	1,092,035
Long-term funding	3,262,120	2,761,795
Derivatives (trading and other liabilities)	47,143	51,103
Letters of Credit Outstanding, Amount	242,000	260,000
Fair Value, Inputs, Level 1
Financial assets
Cash and due from banks	396,677	446,558
Cash and due from banks, Fair Value	396,677	446,558
Interest-bearing deposits in other financial institutions	126,232	149,175
Interest-bearing deposits in other financial institutions, fair value	126,232	149,175
Federal funds sold and securities purchased under agreements to resell	43,000	46,500
Federal funds sold and securities purchased under agreements to resell, fair value	43,000	46,500
Investment securities available for sale	2,636	2,602
Investment securities available for sale, at fair value	2,636	2,602
Fair Value, Inputs, Level 2
Financial assets
Investment securities held to maturity	2,255,395	1,273,536
Investment securities held to maturity, fair value	2,263,322	1,264,674
Investment securities available for sale	3,684,834	4,677,424
Investment securities available for sale, at fair value	3,684,834	4,677,424
FHLB and Federal Reserve Bank stocks	181,180	140,001
Federal Home Loan Bank and Federal Reserve Bank stocks, fair value	181,180	140,001
Commercial loans held for sale	4,772	12,474
Commercial Loans Held-for-sale, Fair Value Disclosure	4,772	12,474
Residential Loans on Real Estate, Carrying Amount of Mortgages	41,620	108,010
Residential Held-for-sale, Fair Value Disclosure	41,620	108,010
Bank owned life insurance	588,440	585,290
Bank owned life insurance, fair value	588,440	585,290
Derivatives (trading and other assets)	50,107	54,974
Derivatives (trading and other assets), fair value	50,107	54,974
Financial liabilities
Brokered CDs and other time deposits	1,940,330	1,606,127
Brokered CDs and other time deposits, fair value	1,940,330	1,606,127
Short-term funding	1,402,482	1,092,035
Short-term funding, fair value	1,402,482	1,092,035
Long-term funding	3,262,120	2,761,795
Long-term funding, fair value	3,288,139	2,791,841
Standby letters of credit	2,394	2,566
Standby letters of credit, fair value	2,394	2,566
Derivatives (trading and other liabilities)	48,674	53,679
Derivatives (trading and other liabilities), fair value	48,674	53,679
Fair Value, Inputs, Level 3
Financial assets
Investment securities available for sale	0	200
Investment securities available for sale, at fair value	0	200
Loans, net	20,501,968	19,776,381
Loans, net, fair value	20,377,586	19,680,317
Derivatives (trading and other assets)	2,839	3,114
Derivatives (trading and other assets), fair value	2,839	3,114
Financial liabilities
Noninterest-bearing demand, savings, interest-bearing demand, and money market accounts	19,677,850	20,282,321
Noninterest-bearing demand, savings, interest-bearing demand, and money market deposits, fair value	$ 19,677,850	$ 20,282,321

Fair Value Measurements (Detail

Fair Value Measurements (Details Textuals)	6 Months Ended
	Jun. 30, 2017
Fair Value of Assets and Liabilities [Line Items]
Closing ratio	88.00%

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		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Pension Plan:
Net period benefit cost for the pension and postretirement plans
Service cost	$ 1,782	$ 1,725	$ 3,563	$ 3,450
Interest cost	1,756	1,780	3,512	3,560
Expected return on plan assets	(4,882)	(5,065)	(9,763)	(10,130)
Amortization of prior service cost	(18)	12	(37)	25
Amortization of actuarial loss	487	483	975	965
Total net pension and periodic benefit cost	(875)	(1,065)	(1,750)	(2,130)
Postretirement Plan:
Net period benefit cost for the pension and postretirement plans
Interest cost	24	36	48	72
Amortization of prior service cost	(19)	0	(38)	0
Total net pension and periodic benefit cost	$ 5	$ 36	$ 10	$ 72

Segment Reporting (Details)

Segment Reporting (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Segment Income Statement Data Abstract
Net interest income	$ 183,819	$ 176,717	$ 364,093	$ 348,704
Noninterest income	82,410	82,168	162,241	165,360
Total revenue	266,229	258,885	526,334	514,064
Credit provision	12,000	14,000	21,000	34,000
Noninterest expense	176,316	174,360	350,007	348,331
Income (loss) before income taxes	77,913	70,525	155,327	131,733
Income tax expense (benefit)	19,930	21,434	41,074	40,108
Net income	$ 57,983	$ 49,091	$ 114,253	$ 91,625
Return on average allocated capital (ROCET1)	10.60%	9.90%	10.60%	9.20%
Segment Balance Sheet Data
Average earning assets	$ 26,744,555	$ 25,968,049	$ 26,543,054	$ 25,620,211
Average loans	20,521,990	19,641,985	20,298,599	19,282,408
Average deposits	21,523,149	20,288,953	21,494,594	20,431,966
Average allocated capital (CET1)	2,099,825	1,913,241	2,080,892	1,904,861
Operating Segments | Corporate and Commercial Specialty
Segment Income Statement Data Abstract
Net interest income	89,871	80,069	179,259	159,233
Noninterest income	12,497	10,936	24,490	22,549
Total revenue	102,368	91,005	203,749	181,782
Credit provision	11,470	15,114	23,050	27,853
Noninterest expense	39,418	37,140	76,897	71,543
Income (loss) before income taxes	51,480	38,751	103,802	82,386
Income tax expense (benefit)	16,363	13,137	34,012	27,716
Net income	$ 35,117	$ 25,614	$ 69,790	$ 54,670
Return on average allocated capital (ROCET1)	12.50%	9.70%	12.60%	10.50%
Segment Balance Sheet Data
Average earning assets	$ 10,853,881	$ 10,128,726	$ 10,807,106	$ 9,924,378
Average loans	10,841,858	10,115,959	10,797,831	9,913,591
Average deposits	6,447,190	5,570,919	6,433,870	5,744,533
Average allocated capital (CET1)	1,125,494	1,067,203	1,120,082	1,049,431
Operating Segments | Community, Consumer, and Business
Segment Income Statement Data Abstract
Net interest income	90,131	84,969	179,059	170,574
Noninterest income	65,809	65,132	130,679	128,880
Total revenue	155,940	150,101	309,738	299,454
Credit provision	5,764	6,246	10,271	12,388
Noninterest expense	125,242	121,965	241,339	243,260
Income (loss) before income taxes	24,934	21,890	58,128	43,806
Income tax expense (benefit)	8,727	7,662	20,345	15,332
Net income	$ 16,207	$ 14,228	$ 37,783	$ 28,474
Return on average allocated capital (ROCET1)	11.00%	9.00%	13.10%	9.10%
Segment Balance Sheet Data
Average earning assets	$ 9,510,571	$ 9,325,036	$ 9,321,564	$ 9,222,677
Average loans	9,508,683	9,323,720	9,319,719	9,221,370
Average deposits	11,574,028	11,331,214	11,456,200	11,215,704
Average allocated capital (CET1)	588,880	633,829	582,706	630,520
Operating Segments | Risk Management and Shared Services
Segment Income Statement Data Abstract
Net interest income	3,817	11,679	5,775	18,897
Noninterest income	4,104	6,100	7,072	13,931
Total revenue	7,921	17,779	12,847	32,828
Credit provision	(5,234)	(7,360)	(12,321)	(6,241)
Noninterest expense	11,656	15,255	31,771	33,528
Income (loss) before income taxes	1,499	9,884	(6,603)	5,541
Income tax expense (benefit)	(5,160)	635	(13,283)	(2,940)
Net income	$ 6,659	$ 9,249	$ 6,680	$ 8,481
Return on average allocated capital (ROCET1)	4.50%	13.40%	1.10%	3.70%
Segment Balance Sheet Data
Average earning assets	$ 6,380,103	$ 6,514,287	$ 6,414,384	$ 6,473,156
Average loans	171,449	202,306	181,049	147,447
Average deposits	3,501,931	3,386,820	3,604,524	3,471,729
Average allocated capital (CET1)	$ 385,451	$ 212,209	$ 378,104	$ 224,910

Accumulated Other Comprehensi84

Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance			$ (54,679)
Personnel expense	$ (104,683)	$ (102,129)	(209,102)	$ (203,527)
Interest income (Amortization of net unrealized gains on available for sale securities transferred to held to maturity securities)	(1,548)	(1,452)	(2,575)	(3,024)
Total other comprehensive income	2,874	11,286	1,209	46,069
Ending Balance	(53,470)		(53,470)
Investments Securities Available For Sale
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	(22,023)	34,936	(20,079)	459
Other comprehensive income (loss) before reclassifications	5,744	22,321	3,632	82,743
Investment securities gain, net		(3,116)		(6,214)
Personnel expense	0	0	0	0
Interest income (Amortization of net unrealized gains on available for sale securities transferred to held to maturity securities)	(1,548)	(1,452)	(2,575)	(3,024)
Income tax (expense) benefit	(1,601)	(6,773)	(406)	(28,048)
Total other comprehensive income	2,595	10,980	651	45,457
Ending Balance	(19,428)	45,916	(19,428)	45,916
Defined Benefit Pension and Post Retirement Obligations
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	(34,321)	(32,769)	(34,600)	(33,075)
Other comprehensive income (loss) before reclassifications	0	0	0	0
Investment securities gain, net		0		0
Personnel expense	450	495	900	990
Interest income (Amortization of net unrealized gains on available for sale securities transferred to held to maturity securities)	0	0	0	0
Income tax (expense) benefit	(171)	(189)	(342)	(378)
Total other comprehensive income	279	306	558	612
Ending Balance	(34,042)	(32,463)	(34,042)	(32,463)
Accumulated Other Comprehensive Income (Loss)
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	(56,344)	2,167	(54,679)	(32,616)
Other comprehensive income (loss) before reclassifications	5,744	22,321	3,632	82,743
Investment securities gain, net		(3,116)		(6,214)
Personnel expense	450	495	900	990
Interest income (Amortization of net unrealized gains on available for sale securities transferred to held to maturity securities)	(1,548)	(1,452)	(2,575)	(3,024)
Income tax (expense) benefit	(1,772)	(6,962)	(748)	(28,426)
Total other comprehensive income	2,874	11,286	1,209	46,069
Ending Balance	$ (53,470)	$ 13,453	$ (53,470)	$ 13,453

Recent Developments (Details)

Recent Developments (Details) - Bank Mutual Corporation - USD ($) $ in Millions	Jul. 20, 2017	Jun. 30, 2017
Subsequent Event [Line Items]
Assets acquired		$ 2,700
Deposits acquired		$ 1,900
Subsequent Event
Subsequent Event [Line Items]
Consideration transfered (in shares per share)	0.4220
Transaction value of merger	$ 482