Associated Banc-Corp (ASB) 10-K 6 Feb 17 2016 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2016	Feb. 01, 2017	Jun. 30, 2016
Document And Entity Information [Abstract]
Trading Symbol	ASB
Entity Registrant Name	ASSOCIATED BANC-CORP
Entity Central Index Key	7,789
Document Type	10-K
Document Period End Date	Dec. 31, 2016
Amendment Flag	false
Document Fiscal Year Focus	2,016
Document Fiscal Period Focus	FY
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Public Float			$ 2,556,756,000
Entity Common Stock, Shares Outstanding		151,806,015

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
ASSETS
Cash and due from banks	$ 446,558	$ 374,921
Interest-bearing deposits in other financial institutions	149,175	79,764
Federal funds sold and securities purchased under agreements to resell	46,500	19,000
Investment securities held to maturity, at amortized cost	1,273,536	1,168,230
Investment securities available for sale, at fair value	4,680,226	4,967,414
Federal Home Loan Bank and Federal Reserve Bank stocks, at cost	140,001	147,240
Loans held for sale	120,484	124,915
Loans	20,054,716	18,714,343
Allowance for loan losses	(278,335)	(274,264)
Loans, net	19,776,381	18,440,079
Premises and equipment, net	330,315	267,606
Goodwill	971,951	968,844
Mortgage servicing rights, net	61,476	61,341
Other intangible assets, net	15,377	16,458
Trading assets	52,398	32,192
Other assets	1,074,937	1,043,831
Total assets	29,139,315	27,711,835
LIABILITIES AND STOCKHOLDERS’ EQUITY
Noninterest-bearing demand deposits	5,392,208	5,562,466
Interest-bearing deposits	16,496,240	15,445,199
Total deposits	21,888,448	21,007,665
Federal funds purchased and securities sold under agreements to repurchase	508,347	431,438
Other short-term funding	583,688	402,978
Long-term funding	2,761,795	2,676,164
Trading liabilities	51,103	33,430
Accrued expenses and other liabilities	254,622	222,914
Total liabilities	26,048,003	24,774,589
Stockholders’ equity
Preferred equity	159,929	121,379
Common stock	1,630	1,642
Surplus	1,459,498	1,458,522
Retained earnings	1,695,764	1,593,239
Accumulated other comprehensive loss	(54,679)	(32,616)
Treasury stock, at cost	(170,830)	(204,920)
Total common equity	2,931,383	2,815,867
Total stockholders’ equity	3,091,312	2,937,246
Liabilities and Equity	$ 29,139,315	$ 27,711,835
Preferred shares issued (in shares)	165,000	125,114
Preferred shares authorized (par value $1.00 per share) (in shares)	750,000	750,000
Common shares issued (in shares)	163,030,209	164,200,068
Common shares authorized (par value $0.01 per share) (in shares)	250,000,000	250,000,000
Treasury shares of common stock (in shares)	10,909,362	12,960,636

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2016	Dec. 31, 2015
Stockholders’ equity
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	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
INTEREST INCOME
Interest and fees on loans	$ 659,538	$ 615,627	$ 598,582
Interest and dividends on investment securities:
Taxable	95,152	100,292	102,464
Tax-exempt	32,049	31,152	29,064
Other interest	4,829	6,591	6,635
Total interest income	791,568	753,662	736,745
INTEREST EXPENSE
Interest on deposits	50,335	33,125	26,294
Interest on Federal funds purchased and securities sold under agreements to repurchase	1,314	943	1,219
Interest on other short-term funding	2,114	465	785
Interest on long-term funding	30,532	42,851	27,480
Total interest expense	84,295	77,384	55,778
NET INTEREST INCOME	707,273	676,278	680,967
Provision for credit losses	70,000	37,500	16,000
Net interest income after provision for credit losses	637,273	638,778	664,967
NONINTEREST INCOME
Trust service fees	46,867	48,840	48,403
Service charges on deposit accounts	66,609	65,471	68,779
Card-based and other nondeposit fees	50,077	47,912	47,114
Insurance commissions	80,795	75,363	44,421
Brokerage and annuity commissions	16,235	15,378	16,089
Mortgage banking, net	38,121	32,263	21,320
Capital market fees, net	22,059	14,558	12,862
Bank owned life insurance income	14,371	9,796	13,576
Asset gains (losses), net	(86)	2,540	10,830
Investment securities gains, net	9,316	8,133	494
Other	8,519	9,103	6,973
Total noninterest income	352,883	329,357	290,861
NONINTEREST EXPENSE
Personnel expense	414,837	404,741	390,399
Occupancy	56,069	60,896	57,677
Equipment	21,489	23,209	24,784
Technology	57,300	60,613	55,472
Business development and advertising	26,351	25,772	26,144
Other intangible amortization	2,093	3,094	3,747
Loan expense	13,641	14,102	13,866
Legal and professional fees	19,869	17,052	17,485
Foreclosure / OREO expense, net	4,844	5,442	7,264
FDIC expense	34,750	26,000	23,761
Other	51,317	57,426	59,184
Total noninterest expense	702,560	698,347	679,783
Income before income taxes	287,596	269,788	276,045
Income tax expense	87,322	81,487	85,536
Net income	200,274	188,301	190,509
Preferred stock dividends	8,903	7,155	5,002
Net income available to common equity	$ 191,371	$ 181,146	$ 185,507
Earnings per common share:
Basic (in usd per share)	$ 1.27	$ 1.20	$ 1.17
Diluted (in usd per share)	$ 1.26	$ 1.19	$ 1.16
Average common shares outstanding:
Basic (in shares)	148,769	149,350	157,286
Diluted (in shares)	149,961	150,603	158,254

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Statement of Comprehensive Income [Abstract]
Net income	$ 200,274	$ 188,301	$ 190,509
Investment securities available for sale:
Net unrealized gains (losses)	(17,900)	(37,873)	49,038
Net unrealized gains on available for sale securities transferred to held to maturity securities	0	17,434	0
Amortization of net unrealized gains on available for sale securities transferred to held to maturity securities	(5,887)	(555)	0
Reclassification adjustment for net gains realized in net income	(9,316)	(8,133)	(494)
Income tax (expense) benefit	12,565	11,074	(18,636)
Other comprehensive income (loss) on investment securities available for sale	(20,538)	(18,053)	29,908
Defined benefit pension and postretirement obligations:
Prior service cost, net of amortization	(73)	50	58
Plan amendments	1,759	0	0
Net loss, net of amortization	(4,026)	(15,636)	(17,079)
Income tax benefit	815	5,873	6,507
Other comprehensive loss on pension and postretirement obligations	(1,525)	(9,713)	(10,514)
Total other comprehensive income (loss)	(22,063)	(27,766)	19,394
Comprehensive income	$ 178,211	$ 160,535	$ 209,903

Consolidated Statements of Chan

Consolidated Statements of Changes in Stockholders' Equity - USD ($) shares in Thousands, $ in Thousands	Total	Preferred Equity	Common Stock	Surplus	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Treasury Stock
Beginning balance at Dec. 31, 2013	$ 2,891,290	$ 61,862	$ 1,750	$ 1,617,990	$ 1,392,508	$ (24,244)	$ (158,576)
Common stock shares outstanding, beginning balance (in shares) at Dec. 31, 2013			175,013
Preferred stock shares outstanding, beginning balance (in shares) at Dec. 31, 2013		64
Comprehensive income:
Net income	190,509	$ 0	$ 0	0	190,509	0	0
Other comprehensive income	19,394	$ 0	$ 0	0	0	19,394	0
Comprehensive income	209,903
Common stock issued:
Stock-based compensation plans, net (in shares)		0	0
Stock-based compensation plans, net	13,228	$ 0	$ 0	2,553	(21,171)	0	31,846
Purchase of common stock returned to authorized but unissued (in shares)		0	(8,469)
Purchase of common stock returned to authorized but unissued	(150,498)	$ 0	$ (85)	(150,413)	0	0	0
Purchase of treasury stock	(112,312)	0	0	0	0	0	(112,312)
Cash dividends:
Common stock dividends	(58,710)	0	0	0	(58,710)	0	0
Preferred stock dividends	(5,002)	$ 0	$ 0	0	(5,002)	0	0
Purchase of preferred stock (in shares)		(2)	0
Purchase of preferred stock	(2,451)	$ (2,135)	$ 0	0	(316)	0	0
Stock-based compensation expense, net	16,091	0	0	16,091	0	0	0
Tax impact of stock-based compensation	(1,288)	0	0	(1,288)	0	0	0
Ending balance at Dec. 31, 2014	2,800,251	$ 59,727	$ 1,665	1,484,933	1,497,818	(4,850)	(239,042)
Common stock shares outstanding, ending balance (in shares) at Dec. 31, 2014			166,544
Preferred stock shares outstanding, ending balance (in shares) at Dec. 31, 2014		62
Comprehensive income:
Net income	188,301	$ 0	$ 0	0	188,301	0	0
Other comprehensive income	(27,766)	$ 0	$ 0	0	0	(27,766)	0
Comprehensive income	160,535
Common stock issued:
Stock-based compensation plans, net (in shares)		0	0
Stock-based compensation plans, net	20,054	$ 0	$ 0	3,316	(22,538)	0	39,276
Acquisition of Ahmann & Martin Co. (in shares)		0	2,621
Acquisition of Ahmann & Martin Co.	43,530	$ 0	$ 26	43,504	0	0	0
Purchase of common stock returned to authorized but unissued (in shares)		0	(4,965)
Purchase of common stock returned to authorized but unissued	(93,000)	$ 0	$ (49)	(92,951)	0	0	0
Purchase of treasury stock	(5,154)	0	0	0	0	0	(5,154)
Cash dividends:
Common stock dividends	(62,400)	0	0	0	(62,400)	0	0
Preferred stock dividends	(7,155)	$ 0	$ 0	0	(7,155)	0	0
Issuance of preferred stock (in shares)		65	0
Issuance of preferred stock	62,966	$ 62,966	$ 0	0	0	0	0
Other (In Shares)		0	0
Purchase of preferred stock (in shares)		(2)	0
Purchase of preferred stock	(1,335)	$ (1,209)	$ 0	0	(126)	0	0
Stockholders' Equity, Other	(766)	(105)	0	0	(661)	0	0
Stock-based compensation expense, net	18,202	0	0	18,202	0	0	0
Tax impact of stock-based compensation	1,518	0	0	1,518	0	0	0
Ending balance at Dec. 31, 2015	2,937,246	$ 121,379	$ 1,642	1,458,522	1,593,239	(32,616)	(204,920)
Common stock shares outstanding, ending balance (in shares) at Dec. 31, 2015			164,200
Preferred stock shares outstanding, ending balance (in shares) at Dec. 31, 2015		125
Comprehensive income:
Net income	200,274	$ 0	$ 0	0	200,274	0	0
Other comprehensive income	(22,063)	$ 0	$ 0	0	0	(22,063)	0
Comprehensive income	178,211
Common stock issued:
Stock-based compensation plans, net (in shares)		0	0
Stock-based compensation plans, net	21,748	$ 0	$ 0	1,940	(19,356)	0	39,164
Purchase of common stock returned to authorized but unissued (in shares)		0	(1,170)
Purchase of common stock returned to authorized but unissued	(20,007)	$ 0	$ (12)	(19,995)	0	0	0
Purchase of treasury stock	(5,074)	0	0	0	0	0	(5,074)
Cash dividends:
Common stock dividends	(67,855)	0	0	0	(67,855)	0	0
Preferred stock dividends	(8,903)	$ 0	$ 0	0	(8,903)	0	0
Issuance of preferred stock (in shares)		100	0
Issuance of preferred stock	97,066	$ 97,066	$ 0	0	0	0	0
Redemption of preferred stock	(58,903)	$ (57,338)	$ 0	0	(1,565)	0	0
Stock Redeemed or Called During Period, Shares		(60)	0
Purchase of preferred stock (in shares)		0	0
Purchase of preferred stock	(1,248)	$ (1,178)	$ 0	0	(70)	0	0
Stock-based compensation expense, net	21,971	0	0	21,971	0	0	0
Tax impact of stock-based compensation	(2,940)	0	0	(2,940)	0	0	0
Ending balance at Dec. 31, 2016	$ 3,091,312	$ 159,929	$ 1,630	$ 1,459,498	$ 1,695,764	$ (54,679)	$ (170,830)
Common stock shares outstanding, ending balance (in shares) at Dec. 31, 2016			163,030
Preferred stock shares outstanding, ending balance (in shares) at Dec. 31, 2016		165

Consolidated Statements of Cha7

Consolidated Statements of Changes in Stockholders' Equity (Parenthetical) - $ / shares	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Common Stock
Cash dividends:
Common stock, per share	$ 0.45	$ 0.41	$ 0.37

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
CASH FLOWS FROM OPERATING ACTIVITIES
Net income	$ 200,274	$ 188,301	$ 190,509
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for credit losses	70,000	37,500	16,000
Depreciation and amortization	45,434	47,168	50,281
Addition to (recovery of) valuation allowance on mortgage servicing rights, net	(200)	(425)	321
Amortization of mortgage servicing rights	12,327	11,601	11,067
Amortization of other intangible assets	2,093	3,094	3,747
Amortization and accretion on earning assets, funding, and other, net	46,615	39,806	28,145
Deferred income taxes	10,656	(3,522)	9,890
Tax impact of stock based compensation	(2,940)	1,518	(1,288)
Gain on sales of investment securities, net	(9,316)	(8,133)	(494)
Asset (gains) losses, net	86	(2,540)	(10,830)
Gain on mortgage banking activities, net	(27,060)	(20,258)	(13,765)
Mortgage loans originated and acquired for sale	(1,271,124)	(1,228,106)	(1,069,852)
Proceeds from sales of mortgage loans held for sale	1,542,660	1,241,012	1,010,167
Pension contributions	0	0	(21,000)
(Increase) decrease in interest receivable	(7,836)	395	(1,264)
Increase (decrease) in interest payable	(4,642)	3,898	1,536
Net change in other assets and other liabilities	21,915	(9,565)	(3,661)
Net cash provided by operating activities	628,942	301,744	199,509
CASH FLOWS FROM INVESTING ACTIVITIES
Net increase in loans	(1,682,579)	(1,136,793)	(1,736,571)
Purchases of:
Available for sale securities	(1,304,921)	(2,859,793)	(1,096,410)
Held to maturity securities	(195,442)	(250,767)	(229,795)
Federal Home Loan Bank and Federal Reserve Bank stocks	(92,761)	(35,647)	(7,857)
Premises, equipment, and software, net of disposals	(103,881)	(54,636)	(50,396)
Other assets	(11,057)	(15,187)	(4,496)
Proceeds from:
Sales of available for sale securities	549,555	1,601,947	102,011
Sale of Federal Home Loan Bank and Federal Reserve Bank stocks	100,000	77,514	0
Prepayments, calls, and maturities of available for sale securities	997,701	1,099,625	862,037
Prepayments, calls, and maturities of held to maturity securities	75,796	17,013	6,420
Prepayments, calls and maturities of other assets	27,692	21,236	36,452
Net cash (paid) received in acquisition	(685)	1,132	0
Net cash used in investing activities	(1,640,582)	(1,534,356)	(2,118,605)
CASH FLOWS FROM FINANCING ACTIVITIES
Net increase in deposits	880,783	2,244,161	1,496,337
Net increase (decrease) in short-term funding	257,619	(233,872)	327,362
Repayment of long-term funding	(1,180,038)	(1,500,035)	(155,066)
Proceeds from issuance of long-term funding	1,265,000	250,000	996,030
Proceeds from issuance of common stock for stock-based compensation plans	21,748	20,054	13,228
Proceeds from issuance of preferred stock	97,066	62,966	0
Redemption of preferred stock	(58,903)	0	0
Purchase of preferred stock	(1,248)	(1,335)	(2,451)
Purchase of common stock returned to authorized but unissued	(20,007)	(93,000)	(150,498)
Purchase of treasury stock	0	0	(108,600)
Purchase of treasury stock for tax withholding	(5,074)	(5,154)	(3,712)
Cash dividends on common stock	(67,855)	(62,400)	(58,710)
Cash dividends on preferred stock	(8,903)	(7,155)	(5,002)
Net cash provided by financing activities	1,180,188	674,230	2,348,918
Net increase (decrease) in cash and cash equivalents	168,548	(558,382)	429,822
Cash and cash equivalents at beginning of period	473,685	1,032,067	602,245
Cash and cash equivalents at end of period	642,233	473,685	1,032,067
Supplemental disclosures of cash flow information:
Cash paid for interest	88,269	73,054	54,330
Cash paid for income and franchise taxes	75,558	84,407	72,431
Loans and bank premises transferred to other real estate owned	9,752	10,988	21,413
Capitalized mortgage servicing rights	12,262	12,372	8,253
Loans transferred into held for sale from portfolio, net	256,194	0	0
Fair value of assets acquired, including cash and cash equivalents	522	4,590	0
Fair value ascribed to goodwill and intangible assets	4,119	51,791	0
Fair value of liabilities assumed	1,423	12,851	0
Common stock issued in acquisition	$ 0	$ 43,530	$ 0

Acquisition

Acquisition	12 Months Ended
	Dec. 31, 2016
Business Combinations [Abstract]
Acquisition	Acquisitions On February 17, 2015, the Corporation acquired Ahmann & Martin Co., a risk and employee benefits consulting firm based in Minnesota. The firm was merged into Associated Benefits and Risk Consulting ("ABRC"), the Corporation's insurance brokerage subsidiary. The Corporation's acquisition of Ahmann & Martin Co. enhanced the Corporation's ability to offer clients unique, comprehensive solutions to meet their insurance and financial risk management needs. The transaction was valued at approximately $48 million with the opportunity to increase the consideration by $8 million should certain contingencies be met over a defined period. The transaction was accounted for using the acquisition method of accounting and as such, assets acquired, liabilities assumed and consideration exchanged were recorded at their estimated fair value on the acquisition date. Goodwill from the acquisition represents the excess of the purchase price over the fair value of the net tangible and intangible assets acquired and is not deductible for tax purposes. As a result of the acquisition, the Corporation recorded goodwill of approximately $40 million and other intangible assets of approximately $12 million . Goodwill was assigned to the Corporation's Community, Consumer, and Business segment. See Note 5 for additional information on goodwill and other intangible assets. 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.

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2016
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). See Note 1 for the Corporation’s accounting policy for fair value measurements. 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 3 for additional disclosure regarding the Corporation’s investment securities. 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 14 for additional disclosure regarding the Corporation’s interest rate-related instruments. The discounted cash flow analysis component in the fair value measurement 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 December 31, 2016 , and 2015 , 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 14 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 14 for additional disclosures regarding the Corporation’s commodity contracts. Derivative financial instruments (mortgage derivatives) : Mortgage derivatives include interest rate lock commitments to originate residential mortgage loans held for sale to individual customers and forward commitments to sell residential mortgage loans to various investors. The Corporation relies on an internal valuation model to estimate the fair value of its interest rate lock commitments to originate residential mortgage loans held for sale, which includes grouping the interest rate lock commitments by interest rate and terms, applying an estimated pull-through rate based on historical experience, and then multiplying by quoted investor prices determined to be reasonably applicable to the loan commitment groups based on interest rate, terms, and rate lock expiration dates of the loan commitment groups. 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 14 for additional disclosure regarding the Corporation’s mortgage derivatives. The table below presents the Corporation’s investment securities available for sale and derivative financial instruments measured at fair value on a recurring basis as of December 31, 2016 and 2015 , aggregated by the level in the fair value hierarchy within which those measurements fall. Assets and Liabilities Measured at Fair Value on a Recurring Basis Fair Value Hierarchy December 31, 2016 December 31, 2015 ($ in Thousands) Assets: Investment securities available for sale: U.S. Treasury securities Level 1 $ 1,000 $ 997 Residential mortgage-related securities: FNMA / FHLMC Level 2 639,930 1,414,626 GNMA Level 2 2,004,475 1,590,003 Private-label Level 2 1,121 1,709 GNMA commercial mortgage-related securities Level 2 2,028,898 1,955,310 Other securities (debt and equity) Level 1 1,602 1,569 Other securities (debt and equity) Level 2 3,000 3,000 Other securities (debt and equity) Level 3 200 200 Total investment securities available for sale Level 1 2,602 2,566 Total investment securities available for sale Level 2 4,677,424 4,964,648 Total investment securities available for sale Level 3 200 200 Interest rate-related instruments Level 2 33,671 29,391 Foreign currency exchange forwards Level 2 2,002 1,532 Interest rate lock commitments to originate residential mortgage loans held for sale Level 3 206 958 Forward commitments to sell residential mortgage loans Level 3 2,908 403 Commodity contracts Level 2 16,725 1,269 Purchased options (time deposit) Level 2 2,576 2,715 Liabilities: Interest rate-related instruments Level 2 $ 33,188 $ 30,886 Foreign currency exchange forwards Level 2 1,943 1,398 Commodity contracts Level 2 15,972 1,146 Written options (time deposit) Level 2 2,576 2,715 The table below presents a rollforward of the balance sheet amounts for the years ended December 31, 2016 and 2015 , 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, 2014 $ 200 $ (488 ) Total net gains included in income: Mortgage derivative gain — 1,849 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 For Level 3 assets and liabilities measured at fair value on a recurring basis as of December 31, 2016 , 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 significant unobservable input used in the fair value measurement of the Corporation’s mortgage derivative interest rate lock commitments is the closing ratio, which represents the percentage of loans currently in a lock position which management estimates will ultimately close. The closing ratio calculation takes into consideration historical data and loan-level data, 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 December 31, 2016 , the closing ratio was 90% . 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. Loans Held for Sale: Loans held for sale, which consist generally of current production of certain fixed-rate, first-lien residential mortgage loans, and certain syndicated commercial loans, once a decision has been made to sell such loans, 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. The amount by which cost exceeds estimated fair value is accounted for as a market valuation adjustment. A market valuation adjustment occurred on mortgage loans held for sale due to interest rates rising on rate locked loans, while commercial loans held for sale had a valuation adjustment due to deteriorated credit quality on two loans. Other Real Estate Owned : During 2016 and 2015 , 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 December 31, 2016, 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, resulting in an average discount of approximately 20% . See Note 4 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, which were 10.8% and 9.6% at December 31, 2016 , respectively. 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 5 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. Assets and Liabilities Measured at Fair Value on a Nonrecurring Basis Income Statement Category of Adjustment Recognized in Income Fair Value Hierarchy Fair Value ($ in Thousands) December 31, 2016 Assets: Commercial loans held for sale Level 2 $ 12,474 Provision for credit losses $ (559 ) Mortgage loans held for sale Level 2 108,010 Mortgage banking, net (3,760 ) Impaired loans (1) Level 3 79,270 Provision for credit losses (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 December 31, 2015 Assets: Mortgage loans held for sale Level 2 $ 124,915 Mortgage banking, net $ (155 ) Impaired loans (1) Level 3 41,891 Provision for credit losses (7,796 ) Other real estate owned Level 2 10,988 Foreclosure / OREO expense, net (2,653 ) Mortgage servicing rights Level 3 70,686 Mortgage banking, net 425 (1) Represents individually evaluated impaired loans, net of the related allowance for loan losses. 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. 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. December 31, 2016 December 31, 2015 Fair Value Hierarchy Level Carrying Amount Fair Value Carrying Amount Fair Value ($ in Thousands) Financial assets: Cash and due from banks Level 1 $ 446,558 $ 446,558 $ 374,921 $ 374,921 Interest-bearing deposits in other financial institutions Level 1 149,175 149,175 79,764 79,764 Federal funds sold and securities purchased under agreements to resell Level 1 46,500 46,500 19,000 19,000 Investment securities held to maturity Level 2 1,273,536 1,264,674 1,168,230 1,184,442 Investment securities available for sale Level 1 2,602 2,602 2,566 2,566 Investment securities available for sale Level 2 4,677,424 4,677,424 4,964,648 4,964,648 Investment securities available for sale Level 3 200 200 200 200 FHLB and Federal Reserve Bank stocks Level 2 140,001 140,001 147,240 147,240 Loans held for sale Level 2 120,484 120,484 124,915 124,915 Loans, net Level 3 19,776,381 19,680,317 18,440,079 18,389,832 Bank owned life insurance Level 2 585,290 585,290 583,019 583,019 Derivatives (trading and other assets) Level 2 54,974 54,974 34,907 34,907 Derivatives (trading and other assets) Level 3 3,114 3,114 1,361 1,361 Financial liabilities: Noninterest-bearing demand, savings, interest-bearing demand, and money market accounts Level 3 $ 20,282,321 $ 20,282,321 $ 19,444,863 $ 19,444,863 Brokered CDs and other time deposits Level 2 1,606,127 1,606,127 1,562,802 1,564,464 Short-term funding Level 2 1,092,035 1,092,035 834,416 834,416 Long-term funding Level 2 2,761,795 2,791,841 2,676,164 2,728,112 Standby letters of credit (1) Level 2 2,566 2,566 2,954 2,954 Derivatives (trading and other liabilities) Level 2 53,679 53,679 36,145 36,145 (1) The commitment on standby letters of credit was $260 million and $297 million at December 31, 2016 and 2015 , respectively. See Note 16 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 mortgage 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— The fair value of bank owned life insurance 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.

Investment Securities

Investment Securities	12 Months Ended
	Dec. 31, 2016
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. See Note 1 for the Corporation’s accounting policy for investment securities. The majority of the Corporation's investment securities are mortgage-related securities issued by the Government National Mortgage Association (“GNMA”) or GSEs 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. December 31, 2016 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses 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 December 31, 2015 Amortized Gross Gross Fair Value ($ in Thousands) Investment securities available for sale: U. S. Treasury securities $ 999 $ — $ (2 ) $ 997 Residential mortgage-related securities: FNMA / FHLMC 1,388,995 33,791 (8,160 ) 1,414,626 GNMA 1,605,956 507 (16,460 ) 1,590,003 Private-label 1,722 1 (14 ) 1,709 GNMA commercial mortgage-related securities 1,982,477 1,334 (28,501 ) 1,955,310 Other securities (debt and equity) 4,718 51 — 4,769 Total investment securities available for sale $ 4,984,867 $ 35,684 $ (53,137 ) $ 4,967,414 Investment securities held to maturity: Municipal securities $ 1,043,767 $ 16,803 $ (339 ) $ 1,060,231 Residential mortgage-related securities: FNMA / FHLMC 41,469 513 (645 ) 41,337 GNMA 82,994 189 (309 ) 82,874 Total investment securities held to maturity $ 1,168,230 $ 17,505 $ (1,293 ) $ 1,184,442 The amortized cost and fair values of investment securities available for sale and held to maturity at December 31, 2016 , 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 $ 4,500 $ 4,479 $ 38,791 $ 28,517 Due after one year through five years 1,200 1,200 257,652 264,427 Due after five years through ten years — — 229,063 229,364 Due after ten years — — 620,337 615,367 Total debt securities 5,700 5,679 1,145,843 1,137,675 Residential mortgage-related securities: FNMA / FHLMC 625,234 639,930 37,697 37,443 GNMA 2,028,301 2,004,475 89,996 89,556 Private-label 1,134 1,121 — — GNMA commercial mortgage-related securities 2,064,508 2,028,898 — — Equity securities 18 123 — — Total investment securities $ 4,724,895 $ 4,680,226 $ 1,273,536 $ 1,264,674 Ratio of Fair Value to Amortized Cost 99.1 % 99.3 % During 2016 and 2015, the Corporation restructured its investment securities portfolio from FNMA and FHLMC mortgage-related securities and reinvested into GNMA mortgage-related securities. The Corporation sold approximately $550 million of FNMA and FHLMC mortgage-related securities in 2016 and sold approximately $1.6 billion in 2015, generating net gains on sales of $9 million and $8 million , respectively. The sales of FNMA and FHLMC mortgage-related securities and the subsequent purchase of GNMA mortgage-related securities lowered risk weighted assets and related capital requirements. Total proceeds and gross realized gains and losses from sales of investment securities for each of the three years ended December 31 were as follows. There were no other-than-temporary impairment write-downs on investment securities for 2016 , 2015 , or 2014 . 2016 2015 2014 ($ in Thousands) Gross gains $ 9,518 $ 12,270 $ 1,184 Gross losses (202 ) (4,137 ) (690 ) Investment securities gains, net $ 9,316 $ 8,133 $ 494 Proceeds from sales of investment securities $ 549,555 $ 1,601,947 $ 102,011 Securities with a carrying value of approximately $1.8 billion and $3.2 billion at December 31, 2016 , and December 31, 2015 , respectively, were pledged to secure certain deposits or for other purposes as required or permitted by law. The following represents gross unrealized losses and the related fair value of investment securities available for sale and held to maturity, aggregated by investment category and length of time individual securities have been in a continuous unrealized loss position, at December 31, 2016 . Less than 12 months 12 months or more Total Number of Securities Unrealized Losses Fair Value Number of Securities Unrealized Losses Fair Value Unrealized Losses Fair Value ($ in Thousands) 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 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, 2015 . Less than 12 months 12 months or more Total Number Unrealized Fair Number Unrealized Fair Unrealized Fair ($ in Thousands) Investment securities available for sale: U.S. Treasury securities 1 $ (2 ) $ 997 — $ — $ — $ (2 ) $ 997 Residential mortgage-related securities: FNMA / FHLMC 17 (1,548 ) 220,852 14 (6,612 ) 338,186 (8,160 ) 559,038 GNMA 46 (16,460 ) 1,434,484 — — — (16,460 ) 1,434,484 Private-label 1 (1 ) 83 3 (13 ) 1,565 (14 ) 1,648 GNMA commercial mortgage-related securities 40 (9,610 ) 1,132,844 21 (18,891 ) 448,218 (28,501 ) 1,581,062 Total 105 $ (27,621 ) $ 2,789,260 38 $ (25,516 ) $ 787,969 $ (53,137 ) $ 3,577,229 Investment securities held to maturity: Municipal securities 53 $ (146 ) $ 23,137 24 $ (193 ) $ 9,254 $ (339 ) $ 32,391 Residential mortgage-related securities: FNMA / FHLMC 10 (177 ) 12,754 3 (468 ) 11,106 (645 ) 23,860 GNMA 21 (201 ) 45,499 3 (108 ) 6,797 (309 ) 52,296 Total 84 $ (524 ) $ 81,390 30 $ (769 ) $ 27,157 $ (1,293 ) $ 108,547 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 December 31, 2016 , 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. The increase in unrealized losses at December 31, 2016 is due to the increase in overall interest rates. The U.S. Treasury 3-year and 5-year rates increased by 16 basis points ("bp") and 17 bp, respectively, from December 31, 2015 . 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 December 31, 2016 , and 2015 , the Corporation had FHLB stock of $65 million and $74 million , respectively. The Corporation had Federal Reserve Bank stock of $75 million and $73 million at December 31, 2016 and 2015 , respectively.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2016
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies The accounting and reporting policies of the Corporation conform to U.S. generally accepted accounting principles and to general practice within the financial services industry. The following is a description of the more significant of those policies. Business 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”) is a bank holding company headquartered in Wisconsin. The Corporation provides a full range of banking and related financial services to consumer and commercial customers through its network of bank and nonbank subsidiaries. The Corporation is subject to competition from other financial and non-financial institutions that offer similar or competing products and services. The Corporation is regulated by federal and state agencies and is subject to periodic examinations by those agencies. Basis of Financial Statement Presentation The consolidated financial statements include the accounts of the Parent Company and its wholly-owned subsidiaries. Investments in unconsolidated entities (none of which are considered to be variable interest entities in which the Corporation is the primary beneficiary) are accounted for using the cost method of accounting when the Corporation has determined that the cost method is appropriate. Investments not meeting the criteria for cost method accounting are accounted for using the equity method of accounting. Investments in unconsolidated entities are included in other assets, and the Corporation’s share of income or loss is recorded in other noninterest income, while distributions in excess of the investment are recorded in gain on assets. All significant intercompany balances and transactions have been eliminated in consolidation. 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. During 2016, the Corporation modified the consolidated statements of income from prior periods’ presentation to conform with the current period presentation. Specifically, OREO gains / losses were reclassified from Asset gains (losses), net to Foreclosure / OREO expense, net; loan syndications were reclassified from Card-based and other nondeposit fees to Capital market fees, net; and bond underwriting was reclassified from Other noninterest income to Capital market fees, net. In addition, the Corporation combined the lease financing portfolio with the commercial and industrial portfolio for disclosure purposes. All prior periods have been reclassified to reflect these immaterial reclassifications. During the first quarter of 2016, the Corporation adopted a new accounting standard related to simplifying the presentation of debt issuance costs. Under this new accounting standard, debt issuance costs are still capitalized; however, they are reflected on the balance sheet with the related debt issued rather than within other assets. All prior period balance sheets were required to be restated to reflect this change in presentation. Investment Securities Securities are classified as held to maturity or available for sale at the time of purchase. Investment securities classified as held to maturity, which management has the positive intent and ability to hold to maturity, are reported at amortized cost. Investment securities classified as available for sale, which management has the intent and ability to hold for an indefinite period of time, but not necessarily to maturity, are carried at fair value, with unrealized gains and losses, net of related deferred income taxes, included in stockholders’ equity as a separate component of other comprehensive income. Any decision to sell investment securities available for sale would be based on various factors, including, but not limited to, asset / liability management strategies, changes in interest rates or prepayment risks, liquidity needs, or regulatory capital considerations. Realized gains or losses on investment security sales (using specific identification method) are included in investment securities gains (losses), net, in the consolidated statements of income. Premiums and discounts are amortized or accreted into interest income over the estimated life (earlier of call date, maturity, or estimated life) of the related security, using a prospective method that approximates level yield. In certain situations, management may elect to transfer certain investment securities from the available for sale classification to the held to maturity classification. In such cases, the investment securities are reclassified at fair value at the time of transfer. Any unrealized gain or loss included in accumulated other comprehensive income (loss) at the time of transfer is retained therein and amortized over the remaining life of the investment security as an adjustment to yield. Declines in the fair value of investment securities (with certain exceptions for debt securities noted below) that are deemed to be other-than-temporary are charged to earnings as a realized loss, and a new cost basis for the investment security is established. In evaluating other-than-temporary impairment, management considers the length of time and extent to which the security has been in an unrealized loss position, changes in security ratings, the financial condition and near-term prospects of the issuer, as well as security and industry specific economic conditions. In addition, the Corporation considers the intent and ability to retain its investment in the issuer for a period of time sufficient to allow for any anticipated recovery in fair value in the near term. Declines in the fair value of debt securities below amortized cost are deemed to be other-than-temporary in circumstances where: (1) the Corporation has the intent to sell a security; (2) it is more likely than not that the Corporation will be required to sell the security before recovery of its amortized cost basis; or (3) the Corporation does not expect to recover the entire amortized cost basis of the security. If the Corporation intends to sell a security or if it is more likely than not that the Corporation will be required to sell the security before recovery, an other-than-temporary impairment write-down is recognized in earnings equal to the difference between the security’s amortized cost basis and its fair value. If an entity does not intend to sell the security or it is more likely than not that it will not be required to sell the security before recovery, the other-than-temporary impairment write-down is separated into an amount representing credit loss, which is recognized in earnings, and an amount related to all other factors, which is recognized in other comprehensive income. Declines in value determined to be other-than-temporary are included in investment securities gains (losses), net, in the consolidated statements of income. See Note 3 for additional information on investment securities. 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. See Note 3 for additional information on the FHLB and Federal Reserve Bank Stocks. Loans Held for Sale Loans held for sale, which consist generally of current production of certain fixed-rate, first-lien residential mortgage loans, are carried at the lower of cost or estimated fair value as determined on an aggregate basis. The amount by which cost exceeds estimated fair value is accounted for as a market valuation adjustment to the carrying value of the loans. Changes, if any, in the market valuation adjustment are included in mortgage banking, net, in the consolidated statements of income. Loans Loans that management has the intent and ability to hold for the foreseeable future or until maturity or pay-off are reported at their outstanding principal balances, net of any deferred fees and costs on originated loans. Origination fee income received on loans and amounts representing the estimated direct costs of origination are deferred and amortized to interest income over the life of the loan using the effective interest method. An allowance for loan losses is established for estimated credit losses in the loan portfolio. See Allowance for Loan Losses below for further policy discussion. Nonaccrual Loans : 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. This determination is based on management's review of current information and other events regarding the borrowers’ ability to repay their obligations. 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. Interest income on loans is based on the principal balance outstanding computed using the effective interest method. The accrual of interest income for commercial loans is discontinued when there is a clear indication that the borrower’s cash flow may not be sufficient to meet payments as they become due, while the accrual of interest income for consumer loans is discontinued when loans reach specific delinquency levels. Loans are considered past due if the required principal and interest payments have not been received as of the date such payments were due. Loans are generally placed on nonaccrual status when contractually past due 90 days or more as to interest or principal payments, unless the loan is well secured and in the process of collection. Additionally, whenever management becomes aware of facts or circumstances that may adversely impact the collectability of principal or interest on loans, it is management’s practice to place such loans on a nonaccrual status immediately, rather than delaying such action until the loans become 90 days past due. When a loan is placed on nonaccrual status, previously accrued and uncollected interest is reversed, amortization of related deferred loan fees or costs is suspended, and income is recorded only to the extent that interest payments are subsequently received in cash and a determination has been made that the principal and interest of the loan is collectible. If collectability of the principal and interest is in doubt, payments received are applied to loan principal. While a loan is in nonaccrual status, some or all of the cash interest payments received may be treated as interest income on a cash basis as long as the remaining recorded investment in the loan (i.e., after charge off of identified losses, if any) is deemed to be fully collectible. The determination as to the ultimate collectability of the loan's remaining recorded investment must be supported by a current, well documented credit evaluation of the borrower’s financial condition and prospects for repayment, including consideration of the borrower’s sustained historical repayment performance and other relevant factors. A nonaccrual loan is returned to accrual status when all delinquent principal and interest payments become current in accordance with the terms of the loan agreement, the borrower has demonstrated a period of sustained repayment performance, and the ultimate collectability of the total contractual principal and interest is no longer in doubt. A sustained period of repayment performance generally would be a minimum of six months. See Note 4 for additional information on loans. Troubled Debt Restructurings (“Restructured Loans”) : Loans are considered restructured loans if concessions have been granted to borrowers that are experiencing financial difficulty. The concessions granted generally involve the modification of terms of the loan, such as changes in payment schedule or interest rate, which generally would not otherwise be considered. Restructured loans can involve loans remaining on nonaccrual, moving to nonaccrual, or continuing on accrual status, depending on the individual facts and circumstances of the borrower. Nonaccrual restructured loans are included and treated with all other nonaccrual loans. In addition, all accruing restructured loans are reported as troubled debt restructurings, which are considered and accounted for as impaired loans. Generally, restructured loans remain on nonaccrual until the customer has attained a sustained period of repayment performance under the modified loan terms (generally a minimum of six months). However, performance prior to the restructuring, or significant events that coincide with the restructuring, are considered in assessing whether the borrower can meet the new terms and whether the loan should be returned to or maintained on accrual status. If the borrower’s ability to meet the revised payment schedule is not reasonably assured, the loan remains on nonaccrual status. See Note 4 for additional information on restructured loans. Allowance for Loan Losses : The allowance for loan losses is a reserve for estimated credit losses on individually evaluated loans determined to be impaired as well as estimated credit losses inherent in the loan portfolio, and is based on quarterly evaluations of the collectability and historical loss experience of loans. Actual credit losses, net of recoveries, are deducted from the allowance for loan losses. A provision for loan losses, which is a charge against earnings, is recorded to bring the allowance for loan losses to a level that, in management’s judgment, is appropriate to absorb probable losses in the loan portfolio. The methodology applied by the Corporation, designed to assess the appropriateness of the allowance for loan losses, is based upon management’s ongoing review and grading of the loan portfolio into criticized loan categories (defined as specific loans warranting either specific allocation, or a criticized status of special mention, substandard, doubtful, or loss). The methodology also focuses on evaluation of several factors, including but not limited to: evaluation of facts and issues related to specific loans, management’s ongoing review and grading of the loan portfolio, consideration of historical loan loss and delinquency experience on each portfolio category, trends in past due and nonaccrual loans, the level of potential problem loans, the risk characteristics of the various classifications of loans, changes in the size and character of the loan portfolio, concentrations of loans to specific borrowers or industries, existing economic conditions, the fair value of underlying collateral, and other qualitative and quantitative factors which could affect potential credit losses. Because each of the criteria used is subject to change, the analysis of the allowance for loan losses is not necessarily indicative of the trend of future loan losses in any particular loan category. The total allowance for loan losses is available to absorb losses from any segment of the loan portfolio. When an individual loan is determined to be impaired, the allowance for loan losses attributable to the loan is allocated based on management’s estimate of the borrower’s ability to repay the loan given the availability of collateral, other sources of cash flows, as well as evaluation of legal options available to the Corporation. The amount of impairment is measured based upon the present value of expected future cash flows discounted at the loan’s effective interest rate, the fair value of the underlying collateral less applicable selling costs, or the observable market price of the loan. If foreclosure is probable or the loan is collateral dependent, impairment is measured using the fair value of the loan’s collateral, less costs to sell. Large groups of homogeneous loans, such as residential mortgage, home equity, and other consumer, are collectively evaluated for impairment. Management believes that the level of the allowance for loan losses is appropriate. While management uses currently available information to recognize losses on loans, future adjustments to the allowance for loan losses may be necessary based on newly received appraisals, updated commercial customer financial statements, rapidly deteriorating cash flow, and changes in economic conditions that affect our customers. In addition, various regulatory agencies, as an integral part of their examination process, periodically review the Corporation’s allowance for loan losses. Such agencies may require additions to the allowance for loan losses or may require that certain loan balances be charged off or downgraded into criticized loan categories when their credit evaluations differ from those of management based on their judgments about information available to them at the time of their examinations. See Loans and Troubled Debt Restructurings above for further policy discussion and see Note 4 for additional information on the allowance for loan losses. Other Real Estate Owned Other real estate owned is included in other assets in the consolidated balance sheets and is comprised of property acquired through a foreclosure proceeding or acceptance of a deed-in-lieu of foreclosure, and loans classified as in-substance foreclosure. Other real estate owned is recorded at the fair value of the underlying property collateral, less estimated selling costs. This fair value becomes the new cost basis for the foreclosed asset. The initial write-down, if any, will be recorded as a charge off against the allowance for loan losses. Any subsequent write-downs to reflect current fair value, as well as gains and losses on disposition and revenues and expenses incurred in maintaining such properties, are expensed as incurred. Other real estate owned also includes bank premises formerly but no longer used for banking as well as property originally acquired for future expansion but no longer intended to be used for that purpose. Banking premises are transferred at the lower of carrying value or fair value, less estimated selling costs and any write-down is expensed as incurred. Allowance for Unfunded Commitments 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 in the consolidated balance sheets. The determination of the appropriate level of the allowance for unfunded commitments is based upon an evaluation of the unfunded credit facilities, including an assessment of historical commitment utilization experience and credit risk grading of the loan. Net adjustments to the allowance for unfunded commitments are included in the provision for credit losses in the consolidated statements of income. See Note 4 and Note 16 for additional information on the allowance for unfunded commitments. Mortgage Repurchase Reserve The Corporation sells residential mortgage loans to investors in the normal course of business. Residential mortgage loans sold to investors are predominantly conventional residential first lien mortgages originated under the usual underwriting procedures, and are most often sold on a nonrecourse basis, primarily to the Government Sponsored Enterprises ("GSE"). The Corporation’s agreements to sell residential mortgage loans usually require certain representations and warranties on the underlying loans sold, related to credit information, loan documentation, collateral, and insurability, which if subsequently untrue or breached, could require the Corporation to indemnify or repurchase certain loans affected. To a much lesser degree, the Corporation may 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 indemnification or repurchase could be required if the loan had defined delinquency issues during the limited recourse periods. The balance in the repurchase reserve at the balance sheet date reflects the estimated amount of potential loss the Corporation could incur from repurchasing a loan (“put back” requests), as well as loss reimbursements, indemnification, and other settlement resolutions (“make whole” payments). See Note 16 for additional information on the mortgage repurchase reserve. Premises and Equipment and Software Premises and equipment are stated at cost less accumulated depreciation and amortization. Depreciation and amortization are computed on the straight-line method over the estimated useful lives of the related assets or the lease term. Maintenance and repairs are charged to expense as incurred, while additions or major improvements are capitalized and depreciated over the estimated useful lives. Leasehold improvements are amortized on a straight-line basis over the lesser of the lease terms or the estimated useful lives of the improvements. Software, included in other assets in the consolidated balance sheets, is amortized on a straight-line basis over the lesser of the contract terms or the estimated useful life of the software. See Note 6 for additional information on premises and equipment. Goodwill and Intangible Assets Goodwill and Other Intangible Assets : The excess of the cost of an acquisition over the fair value of the net assets acquired consists primarily of goodwill, core deposit intangibles, and other identifiable intangibles (primarily related to customer relationships acquired). Core deposit intangibles have estimated finite lives and are amortized on an accelerated basis to expense over a 10 -year period. The other intangibles have estimated finite lives and are amortized on an accelerated basis to expense over their weighted average life (a weighted average life of 12 years for both 2016 and 2015 ). The Corporation reviews long-lived assets and certain identifiable intangibles for impairment at least annually, or whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable, in which case an impairment charge would be recorded. 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 impairment testing process is conducted by assigning net assets and goodwill to each reporting unit. An initial qualitative evaluation is made to assess the likelihood of impairment and determine whether further quantitative testing to calculate the fair value is necessary. When the qualitative evaluation indicates that impairment is more likely than not, quantitative testing is required whereby the fair value of each reporting unit is calculated and compared to the recorded book value, “step one.” If the calculated fair value of the reporting unit exceeds its carrying value, goodwill is not considered impaired and “step two” is not considered necessary. If the carrying value of a reporting unit exceeds its calculated fair value, the impairment test continues (“step two”) by comparing the carrying value of the reporting unit’s goodwill to the implied fair value of goodwill. The implied fair value is computed by adjusting all assets and liabilities of the reporting unit to current fair value with the offset adjustment to goodwill. The adjusted goodwill balance is the implied fair value of the goodwill. An impairment charge is recognized if the carrying value of goodwill exceeds the implied fair value of goodwill. See Note 5 for additional information on goodwill and other intangible assets. Mortgage Servicing Rights : The Corporation sells residential mortgage loans in the secondary market and typically retains the right to service the loans sold. Upon sale, a mortgage servicing rights asset is capitalized, which represents the then current fair value of future net cash flows expected to be realized for performing servicing activities. Mortgage servicing rights, when purchased, are initially recorded at fair value. As the Corporation has not elected to subsequently measure any class of servicing assets under the fair value measurement method, the Corporation follows the amortization method. 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. Mortgage servicing rights are carried at the lower of the initial capitalized amount, net of accumulated amortization, or estimated fair value, in the consolidated balance sheets. The Corporation periodically 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 5 for additional information on mortgage servicing rights. Income Taxes Amounts provided for income tax expense are based on income reported for financial statement purposes and do not necessarily represent amounts currently payable under tax laws. Deferred income taxes, which arise principally from temporary differences between the amounts reported in the financial statements and the tax bases of assets and liabilities, are included in the amounts provided for income taxes. In assessing the realizability of deferred tax assets, management considers whether it is more likely than not that some portion or all of the deferred tax assets will not be realized. The ultimate realization of deferred tax assets is dependent upon the generation of future taxable income and tax planning strategies which will create taxable income during the periods in which those temporary differences become deductible. Management considers the scheduled reversal of deferred tax liabilities, the amount of taxes paid in available carryback years, projected future taxable income, and, if necessary, tax planning strategies in making this assessment. The Corporation files a consolidated federal income tax return and separate or combined state income tax returns. Accordingly, amounts equal to tax benefits of those subsidiaries having taxable federal or state losses or credits are offset by other subsidiaries that incur federal or state tax liabilities. It is the Corporation’s policy to provide for uncertainty in income taxes as a part of income tax expense based upon management’s assessment of whether a tax benefit is more likely than not to be sustained upon examination by tax authorities. At December 31, 2016 and 2015 , the Corporation believes it has appropriately accounted for any unrecognized tax benefits. To the extent the Corporation prevails in matters for which a liability for an unrecognized tax benefit was established or is required to pay amounts in excess of the liability established, the Corporation’s effective tax rate in a given financial statement period may be effected. See Note 13 for additional information on income taxes. Derivative and Hedging Activities Derivative instruments, including derivative instruments embedded in other contracts, are carried at fair value on the consolidated balance sheets with changes in the fair value recorded to earnings or accumulated other comprehensive income, as appropriate. On the date the derivative contract is entered into, the Corporation designates the derivative as a fair value hedge (i.e., a hedge of the fair value of a recognized asset or liability), a cash flow hedge (i.e., a hedge of the variability of cash flows to be received or paid related to a recognized asset or liability), or a free-standing derivative instrument. For a derivative designated as a fair value hedge, the changes in the fair value of the derivative instrument and the changes in the fair value of the hedged asset or liability are recognized in current period earnings as an increase or decrease to the carrying value of the hedged item on the balance sheet and in the related income statement account. For a derivative designated as a cash flow hedge, the effective portions of changes in the fair value of the derivative instrument are recorded in other comprehensive income and the ineffective portions of changes in the fair value of a derivative instrument are recognized in current period earnings as an adjustment to the related income statement account. Amounts within accumulated other comprehensive income are reclassified into earnings in the period the hedged item affects earnings. For a derivative is designated as a free-standing derivative instrument, changes in fair value are reported in current period earnings. At December 31, 2016 and 2015 , the Corporation only had free-standing derivative instruments to facilitate customer borrowing activity. These free-standing derivative instruments included: interest rate risk management, commodity hedging, and foreign currency exchange solutions. See Note 14 for additional information on derivative and hedging activities. Retirement Plans The funded status of the retirement plans are recognized as an asset or liability in the consolidated balance sheets, and changes in that funded status are recognized in the year in which the changes occur through other comprehensive income. Plan assets and benefit obligations are measured as of fiscal year end. The measurement of the projected benefit obligation and pension expense involve actuarial valuation methods and the use of various actuarial and economic assumptions. The Corporation monitors the assumptions and updates them periodically. Due to the long-term nature of the pension plan obligation, actual results may differ significantly from estimations. Such differences are adjusted over time as the assumptions are replaced by facts and values are recalculated. See Note 12 for additional information on the Corporation’s retirement plans. 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 common 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.

Loans

Loans	12 Months Ended
	Dec. 31, 2016
Receivables [Abstract]
Loans	Loans Loans at December 31 are summarized below. 2016 2015 ($ in Thousands) Commercial and industrial $ 6,489,014 $ 6,190,683 Commercial real estate — owner occupied 897,724 918,212 Commercial and business lending 7,386,738 7,108,895 Commercial real estate — investor 3,574,732 3,234,266 Real estate construction 1,432,497 1,162,145 Commercial real estate lending 5,007,229 4,396,411 Total commercial 12,393,967 11,505,306 Residential mortgage 6,332,327 5,783,267 Home equity 934,443 1,005,802 Other consumer 393,979 419,968 Total consumer 7,660,749 7,209,037 Total loans $ 20,054,716 $ 18,714,343 The Corporation has granted loans to their directors, executive officers, or their related interests. These loans were made on substantially the same terms, including rates and collateral, as those prevailing at the time for comparable transactions with other unrelated customers, and do not involve more than a normal risk of collection. These loans to related parties are summarized below. 2016 ($ in Thousands) Balance at beginning of year $ 36,597 New loans 10,677 Repayments (11,089 ) Change due to status of executive officers and directors (8,596 ) Balance at end of year $ 27,589 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 loans $ 19,251,353 $ 176,918 $ 351,142 $ 275,303 $ 20,054,716 The following table presents commercial and consumer loans by credit quality indicator at December 31, 2015 . Pass Special Mention Potential Problem Nonaccrual Total ($ in Thousands) Commercial and industrial $ 5,522,809 $ 341,169 $ 233,130 $ 93,575 $ 6,190,683 Commercial real estate - owner occupied 835,572 38,885 35,706 8,049 918,212 Commercial and business lending 6,358,381 380,054 268,836 101,624 7,108,895 Commercial real estate - investor 3,153,703 45,976 25,944 8,643 3,234,266 Real estate construction 1,157,034 252 3,919 940 1,162,145 Commercial real estate lending 4,310,737 46,228 29,863 9,583 4,396,411 Total commercial 10,669,118 426,282 298,699 111,207 11,505,306 Residential mortgage 5,727,437 1,552 2,796 51,482 5,783,267 Home equity 988,574 1,762 222 15,244 1,005,802 Other consumer 419,087 556 — 325 419,968 Total consumer 7,135,098 3,870 3,018 67,051 7,209,037 Total loans $ 17,804,216 $ 430,152 $ 301,717 $ 178,258 $ 18,714,343 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. See Note 1 for the Corporation's accounting policy for loans. 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 loans are reviewed at a minimum on a quarterly basis, while pass 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 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 loans $ 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, $224 million or 81% were current with respect to payment at December 31, 2016 . The following table presents loans by past due status at December 31, 2015 . Current 30-59 Days Past Due 60-89 Days Past Due 90 Days or More Past Due (a) Nonaccrual (b) Total ($ in Thousands) Commercial and industrial $ 6,095,848 $ 602 $ 409 $ 249 $ 93,575 $ 6,190,683 Commercial real estate - owner occupied 903,021 7,142 — — 8,049 918,212 Commercial and business lending 6,998,869 7,744 409 249 101,624 7,108,895 Commercial real estate - investor 3,225,332 291 — — 8,643 3,234,266 Real estate construction 1,160,909 270 26 — 940 1,162,145 Commercial real estate lending 4,386,241 561 26 — 9,583 4,396,411 Total commercial 11,385,110 8,305 435 249 111,207 11,505,306 Residential mortgage 5,726,855 4,491 439 — 51,482 5,783,267 Home equity 982,639 6,190 1,729 — 15,244 1,005,802 Other consumer 416,374 1,195 675 1,399 325 419,968 Total consumer 7,125,868 11,876 2,843 1,399 67,051 7,209,037 Total loans $ 18,510,978 $ 20,181 $ 3,278 $ 1,648 $ 178,258 $ 18,714,343 (a) The recorded investment in loans past due 90 days or more and still accruing totaled $2 million at December 31, 2015 (the same as the reported balances for the accruing loans noted above). (b) Of the total nonaccrual loans, $124 million or 69% were current with respect to payment at December 31, 2015 . The following table presents impaired loans at December 31, 2016 . Recorded Unpaid Related Average Interest ($ 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 $ 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 $ 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 impaired 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 . The following table presents impaired loans at December 31, 2015 . Recorded Investment Unpaid Principal Balance Related Allowance Average Recorded Investment Interest Income Recognized ($ in Thousands) Loans with a related allowance Commercial and industrial $ 57,785 $ 59,409 $ 8,162 $ 46,833 $ 855 Commercial real estate — owner occupied 9,705 9,804 448 10,087 412 Commercial and business lending 67,490 69,213 8,610 56,920 1,267 Commercial real estate — investor 27,822 29,444 1,831 28,278 1,914 Real estate construction 1,450 2,154 453 1,667 66 Commercial real estate lending 29,272 31,598 2,284 29,945 1,980 Total commercial 96,762 100,811 10,894 86,865 3,247 Residential mortgage 66,590 71,084 12,462 68,183 2,374 Home equity 21,769 23,989 10,118 22,624 1,147 Other consumer 1,154 1,225 195 1,199 30 Total consumer 89,513 96,298 22,775 92,006 3,551 Total loans $ 186,275 $ 197,109 $ 33,669 $ 178,871 $ 6,798 Loans with no related allowance Commercial and industrial $ 65,083 $ 72,259 $ — $ 79,573 $ 1,657 Commercial real estate — owner occupied 6,221 6,648 — 6,534 15 Commercial and business lending 71,304 78,907 — 86,107 1,672 Commercial real estate — investor 2,736 2,840 — 2,763 90 Real estate construction — — — — — Commercial real estate lending 2,736 2,840 — 2,763 90 Total commercial 74,040 81,747 — 88,870 1,762 Residential mortgage 4,762 5,033 — 4,726 126 Home equity 544 544 — 544 30 Other consumer — — — — — Total consumer 5,306 5,577 — 5,270 156 Total loans $ 79,346 $ 87,324 $ — $ 94,140 $ 1,918 Total Commercial and industrial $ 122,868 $ 131,668 $ 8,162 $ 126,406 $ 2,512 Commercial real estate — owner occupied 15,926 16,452 448 16,621 427 Commercial and business lending 138,794 148,120 8,610 143,027 2,939 Commercial real estate — investor 30,558 32,284 1,831 31,041 2,004 Real estate construction 1,450 2,154 453 1,667 66 Commercial real estate lending 32,008 34,438 2,284 32,708 2,070 Total commercial 170,802 182,558 10,894 175,735 5,009 Residential mortgage 71,352 76,117 12,462 72,909 2,500 Home equity 22,313 24,533 10,118 23,168 1,177 Other consumer 1,154 1,225 195 1,199 30 Total consumer 94,819 101,875 22,775 97,276 3,707 Total impaired loans (a) $ 265,621 $ 284,433 $ 33,669 $ 273,011 $ 8,716 (a) The net recorded investment (defined as recorded investment, net of the related allowance) of the impaired loans represented 82% of the unpaid principal balance at December 31, 2015 . Troubled Debt Restructurings (“Restructured Loans”): Loans are considered restructured loans if concessions have been granted to borrowers that are experiencing financial difficulty. See Note 1 for the Corporation's accounting policy for troubled debt restructurings. As of December 31, 2016 there was approximately $7 million of commitments to lend additional funds to borrowers with restructured loans. The following table presents nonaccrual and performing restructured loans by loan portfolio. December 31, 2016 December 31, 2015 December 31, 2014 Performing Restructured Loans Nonaccrual Restructured Loans (a) Performing Restructured Loans Nonaccrual Restructured Loans (a) Performing Restructured Loans Nonaccrual Restructured Loans (a) ($ in Thousands) Commercial and industrial $ 31,884 $ 1,276 $ 29,293 $ 1,714 $ 33,892 $ 3,260 Commercial real estate — owner occupied 5,490 2,220 7,877 2,703 10,454 5,656 Commercial real estate — investor 15,289 924 21,915 3,936 23,127 15,216 Real estate construction 359 150 510 177 727 2,438 Residential mortgage 18,100 21,906 19,870 24,592 20,833 26,049 Home equity 7,756 2,877 7,069 4,522 8,209 4,838 Other consumer 979 32 829 40 974 199 Total restructured loans $ 79,857 $ 29,385 $ 87,363 $ 37,684 $ 98,216 $ 57,656 (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 years ended December 31, 2016 , 2015 and 2014 , respectively, and the recorded investment and unpaid principal balance as of December 31, 2016 , 2015 and 2014 . Year Ended December 31, 2016 Year Ended December 31, 2015 Year Ended December 31, 2014 Number of Loans Recorded Investment (a) Unpaid Principal Balance (b) Number of Loans Recorded Investment (a) Unpaid Principal Balance (b) Number Recorded (a) Unpaid (b) ($ in Thousands) Commercial and industrial 8 $ 1,509 $ 1,526 12 $ 2,219 $ 2,900 15 $ 7,681 $ 7,711 Commercial real estate — owner occupied 1 116 122 5 3,694 3,901 4 1,465 1,625 Commercial real estate — investor — — — 5 21,573 21,640 6 6,097 6,521 Real estate construction 1 65 91 4 78 79 2 15 15 Residential mortgage 63 5,535 5,792 97 10,464 10,996 163 19,675 20,454 Home equity 57 2,030 2,084 88 3,103 3,249 117 3,913 4,308 Other consumer 1 15 16 — — — 2 24 26 Total 131 $ 9,270 $ 9,631 211 $ 41,131 $ 42,765 309 $ 38,870 $ 40,660 (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. For the year ended December 31, 2016 , restructured loan modifications of commercial and industrial, commercial real estate, and real estate construction loans primarily included maturity date extensions, interest rate concessions, payment schedule modifications, or a combination of these concessions. 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 year ended December 31, 2016 . The following table provides the number of loans modified in a troubled debt restructuring during the previous twelve months which subsequently defaulted during the year ended December 31, 2016 , 2015 and 2014 , respectively, as well as the recorded investment in these restructured loans as of December 31, 2016 , 2015 and 2014 , respectively. Year Ended December 31, 2016 Year Ended December 31, 2015 Year Ended December 31, 2014 Number of Loans Recorded Investment Number of Loans Recorded Investment Number of Recorded ($ in Thousands) Commercial and industrial — $ — 2 $ 197 1 $ 52 Commercial real estate — owner occupied — — — — 3 785 Commercial real estate — investor — — — — 13 6,200 Real estate construction — — — — 1 160 Residential mortgage 44 4,102 61 6,815 80 10,032 Home equity 23 457 28 1,220 54 1,802 Other consumer 1 15 — — 3 34 Total 68 $ 4,574 91 $ 8,232 155 $ 19,065 All loans modified in a troubled debt restructuring are evaluated for impairment. The nature and extent of the impairment of restructured loans, including those which have experienced a subsequent payment default, is considered in the determination of an appropriate level of the allowance for loan losses. Allowance for Credit Losses: The allowance for credit losses is comprised of the allowance for loan losses and the allowance for unfunded commitments. The level of the allowance for loan losses represents management’s estimate of an amount appropriate to provide for probable credit losses in the loan portfolio at the balance sheet date. See Note 1 for the Corporation's accounting policy on the allowance for loan losses. 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: Individually evaluated for impairment $ 20,836 $ — $ 3,117 $ — $ 147 $ 3 $ — $ 24,103 Collectively evaluated for impairment 119,290 14,034 42,168 26,932 26,899 20,361 4,548 254,232 Total allowance for loan losses $ 140,126 $ 14,034 $ 45,285 $ 26,932 $ 27,046 $ 20,364 $ 4,548 $ 278,335 Loans: Individually evaluated for impairment $ 180,965 $ 8,439 $ 17,322 $ — $ 7,033 $ 650 $ — $ 214,409 Collectively evaluated for impairment 6,308,049 889,285 3,557,410 1,432,497 6,325,294 933,793 393,979 19,840,307 Total loans $ 6,489,014 $ 897,724 $ 3,574,732 $ 1,432,497 $ 6,332,327 $ 934,443 $ 393,979 $ 20,054,716 For comparison purposes, a summary of the changes in the allowance for loan losses by portfolio segment for the year ended December 31, 2015 , 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, 2014 $ 117,635 $ 16,510 $ 46,333 $ 20,999 $ 31,926 $ 26,464 $ 6,435 $ 266,302 Charge offs (27,687 ) (2,645 ) (4,645 ) (750 ) (5,636 ) (7,048 ) (3,869 ) (52,280 ) Recoveries 9,821 921 4,157 2,268 1,077 3,233 765 22,242 Net charge offs (17,866 ) (1,724 ) (488 ) 1,518 (4,559 ) (3,815 ) (3,104 ) (30,038 ) Provision for loan losses 30,190 3,894 (2,827 ) 2,749 894 906 2,194 38,000 December 31, 2015 $ 129,959 $ 18,680 $ 43,018 $ 25,266 $ 28,261 $ 23,555 $ 5,525 $ 274,264 Allowance for loan losses: Individually evaluated for impairment $ 7,522 $ — $ 229 $ — $ 166 $ 46 $ — $ 7,963 Collectively evaluated for impairment 122,437 18,680 42,789 25,266 28,095 23,509 5,525 266,301 Total allowance for loan losses $ 129,959 $ 18,680 $ 43,018 $ 25,266 $ 28,261 $ 23,555 $ 5,525 $ 274,264 Loans: Individually evaluated for impairment $ 91,569 $ 6,221 $ 5,460 $ — $ 6,956 $ 1,281 $ — $ 111,487 Collectively evaluated for impairment 6,099,114 911,991 3,228,806 1,162,145 5,776,311 1,004,521 419,968 18,602,856 Total loans $ 6,190,683 $ 918,212 $ 3,234,266 $ 1,162,145 $ 5,783,267 $ 1,005,802 $ 419,968 $ 18,714,343 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 16 for additional information on the allowance for unfunded commitments and see Note 1 for the Corporation's accounting policy for allowance for unfunded commitments. A summary of the changes in the allowance for unfunded commitments was as follows. Years Ended December 31, 2016 2015 2014 ($ in Thousands) Allowance for Unfunded Commitments: Balance at beginning of period $ 24,400 $ 24,900 $ 21,900 Provision for unfunded commitments 1,000 (500 ) 3,000 Balance at end of period $ 25,400 $ 24,400 $ 24,900

Goodwill and Intangible Assets

Goodwill and Intangible Assets	12 Months Ended
	Dec. 31, 2016
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. See Note 1 for the Corporation’s accounting policy for goodwill and other intangible assets. The Corporation conducted its most recent annual impairment testing in May 2016, 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 increases 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 2016 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 2016 impairment testing that have changed the Corporation's impairment assessment conclusion. There were no impairment charges recorded in 2016, 2015, or 2014. At December 31, 2016 , the Corporation had goodwill of $972 million , compared to $969 million at December 31, 2015 including goodwill of $428 million assigned to the Corporate and Commercial Specialty segment and the remaining assigned to the Community, Consumer and Business segment. There was an addition to the carrying amount of goodwill of approximately $3 million as a result of two small insurance acquisitions during the first quarter of 2016. 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. Core deposit intangibles of approximately $15 million were fully amortized in 2015 and have been removed from both the gross carrying amount and the accumulated amortization for 2016. There was an addition to the gross carrying amount of other intangibles of $1 million for the customer relationships associated with two small insurance acquisitions that occurred during the first quarter of 2016. See Note 2 for additional information on the Corporation's acquisitions. For core deposit intangibles and other intangibles, changes in the gross carrying amount, accumulated amortization, and net book value were as follows. 2016 2015 2014 ($ in Thousands) Core deposit intangibles: Gross carrying amount $ 4,385 $ 19,545 $ 36,230 Accumulated amortization (4,273 ) (19,152 ) (34,433 ) Net book value $ 112 $ 393 $ 1,797 Amortization during the year $ 281 $ 1,404 $ 2,868 Other intangibles: Gross carrying amount $ 32,410 $ 31,398 $ 19,283 Accumulated amortization (17,145 ) (15,333 ) (13,643 ) Net book value $ 15,265 $ 16,065 $ 5,640 Additions during the period $ 1,012 $ 12,115 $ — Amortization during the year $ 1,812 $ 1,690 $ 879 Mortgage Servicing Rights: 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. See Note 1 for the Corporation’s accounting policy for mortgage servicing rights. See Note 16 for a discussion of the recourse provisions on sold residential mortgage loans. See Note 18 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. 2016 2015 2014 ($ in Thousands) Mortgage servicing rights Mortgage servicing rights at beginning of year $ 62,150 $ 61,379 $ 64,193 Additions 12,262 12,372 8,253 Amortization (12,327 ) (11,601 ) (11,067 ) Mortgage servicing rights at end of year $ 62,085 $ 62,150 $ 61,379 Valuation allowance at beginning of year (809 ) (1,234 ) (913 ) (Additions) recoveries, net 200 425 (321 ) Valuation allowance at end of year (609 ) (809 ) (1,234 ) Mortgage servicing rights, net $ 61,476 $ 61,341 $ 60,145 Fair value of mortgage servicing rights $ 73,149 $ 70,686 $ 66,342 Portfolio of residential mortgage loans serviced for others (“servicing portfolio”) $ 7,974,742 $ 7,915,224 $ 7,999,294 Mortgage servicing rights, net to servicing portfolio 0.77 % 0.77 % 0.75 % Mortgage servicing rights expense (1) $ 12,127 $ 11,176 $ 11,388 (1) 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 December 31, 2016 . 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 Core Deposit Intangibles Other Intangibles Mortgage Servicing Rights ($ in Thousands) Year ending December 31, 2017 $ 112 $ 1,786 $ 9,627 2018 — 1,756 8,134 2019 — 1,457 6,878 2020 — 1,340 5,840 2021 — 1,316 4,970 Beyond 2021 — 7,610 26,636 Total Estimated Amortization Expense $ 112 $ 15,265 $ 62,085

Premises and Equipment

Premises and Equipment	12 Months Ended
	Dec. 31, 2016
Property, Plant and Equipment [Abstract]
Premises and Equipment	Premises and Equipment See Note 1 for the Corporation’s accounting policy for premises and equipment. A summary of premises and equipment at December 31 was as follows. 2016 2015 Estimated Useful Lives Cost Accumulated Depreciation Net Book Value Net Book Value ($ in Thousands) Land — $ 57,471 $ — $ 57,471 $ 52,104 Land improvements 3 – 15 years 12,572 5,929 6,643 6,661 Buildings 5 – 39 years 332,256 130,104 202,152 141,432 Computers 3 – 5 years 42,190 33,139 9,051 6,372 Furniture, fixtures and other equipment 3 – 15 years 162,253 119,704 42,549 49,794 Leasehold improvements 3 – 15 years 34,959 22,510 12,449 11,243 Total premises and equipment $ 641,701 $ 311,386 $ 330,315 $ 267,606 Depreciation and amortization of premises and equipment totaled $32 million in 2016 , $33 million in 2015 , and $34 million in 2014 . The Corporation and certain subsidiaries are obligated under noncancelable operating leases for other facilities and equipment, certain of which provide for increased rentals based upon increases in cost of living adjustments and other operating costs. The approximate minimum annual rentals and commitments under these noncancelable agreements and leases with remaining terms in excess of one year are as follows. ($ in Thousands) 2017 $ 9,711 2018 9,665 2019 9,115 2020 8,133 2021 7,336 Thereafter 20,940 Total $ 64,900 Total rental expense under leases, net of lease income, totaled $8 million in 2016 , $13 million in 2015 , and $11 million in 2014 , respectively. The reduction of rental expense in 2016 was mainly driven by $4 million of leasing income generated by the Milwaukee Center (which was purchased in April 2016).

Deposits

Deposits	12 Months Ended
	Dec. 31, 2016
Deposits [Abstract]
Deposits	Deposits The distribution of deposits at December 31 was as follows. 2016 2015 ($ in Thousands) Noninterest-bearing demand $ 5,392,208 $ 5,562,466 Savings 1,431,494 1,334,420 Interest-bearing demand 4,687,656 3,445,000 Money market 8,770,963 9,102,977 Brokered CDs 52,725 42,443 Other time 1,553,402 1,520,359 Total deposits $ 21,888,448 $ 21,007,665 Time deposits of $100,000 or more were $571 million and $466 million at December 31, 2016 and 2015 , respectively. Time deposits of $250,000 or more were $235 million and $127 million at December 31, 2016 and 2015 , respectively. Aggregate annual maturities of all time deposits at December 31, 2016 , are as follows. Maturities During Year Ending December 31, ($ in Thousands) 2017 $ 932,179 2018 276,642 2019 185,465 2020 131,820 2021 76,740 Thereafter 3,281 Total $ 1,606,127

Short-term Funding

Short-term Funding	12 Months Ended
	Dec. 31, 2016
Short-term Debt [Abstract]
Short-term Funding	Short-Term Funding The components of short-term funding (funding with original contractual maturities of one year or less) at December 31 were as follows. 2016 2015 ($ in Thousands) Federal funds purchased $ 208,150 $ 47,870 Securities sold under agreements to repurchase 300,197 383,568 Federal funds purchased and securities sold under agreements to repurchase 508,347 431,438 FHLB advances 482,000 335,000 Commercial paper 101,688 67,978 Other short-term funding 583,688 402,978 Total short-term funding $ 1,092,035 $ 834,416 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 15 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 December 31, 2016 , the Corporation pledged agency mortgage-related securities with a fair value of $381 million as collateral for the repurchase agreements. Securities pledged as collateral under repurchase agreements are maintained with the Corporation's safekeeping agents and are monitored on a daily basis due to the market risk of fair value changes in the underlying securities. The Corporation generally pledges excess securities to ensure there is sufficient collateral to satisfy short-term fluctuations in both the repurchase agreement balances and the fair value of the underlying securities. The remaining contractual maturity of the securities sold under agreements to repurchase in the consolidated balance sheets are presented in the following table. Remaining Contractual Maturity of the Agreements Overnight and Continuous Up to 30 days 30-90 days Greater than 90 days Total ($ in Thousands) December 31, 2016 Repurchase agreements Agency mortgage-related securities $ 300,197 $ — $ — $ — $ 300,197 Total $ 300,197 $ — $ — $ — $ 300,197 December 31, 2015 Repurchase agreements Agency mortgage-related securities $ 383,568 $ — $ — $ — $ 383,568 Total $ 383,568 $ — $ — $ — $ 383,568

Long-term Funding

Long-term Funding	12 Months Ended
	Dec. 31, 2016
Debt Disclosure [Abstract]
Long-term Funding	Long-Term Funding The components of long-term funding (funding with original contractual maturities greater than one year) at December 31 were as follows. 2016 2015 ($ in Thousands) FHLB advances $ 2,265,188 $ 1,750,225 Senior notes, at par 250,000 680,000 Subordinated notes, at par 250,000 250,000 Other long-term funding and capitalized costs (3,393 ) (4,061 ) Total long-term funding $ 2,761,795 $ 2,676,164 FHLB advances: At December 31, 2016 , the long-term FHLB advances had maturity dates primarily ranging from 2018 through 2019, and had an average interest rate of 0.50% , compared to 0.23% at December 31, 2015 . 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. 2011 Senior Notes: In March 2011, the Corporation issued $300 million of senior notes due March 2016, and callable February 2016, with a 5.125% fixed coupon at a discount. In September 2011, the Corporation “re-opened” the offering and issued an additional $130 million of the same notes at a premium. All of the 2011 senior notes were redeemed in February 2016 at par. 2014 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. 2014 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. Under agreements with the Federal Home Loan Bank of Chicago, FHLB advances (short-term and long-term) are secured by qualifying mortgages of the subsidiary bank (such as residential mortgage, residential mortgage loans held for sale, home equity, and commercial real estate) and by specific investment securities for certain FHLB advances. At December 31, 2016 , the Corporation had $6 billion of total collateral capacity supported by residential mortgage and home equity loans. Total short-term and long-term FHLB advances outstanding at December 31, 2016 , was $2.7 billion . The table below summarizes the maturities of the Corporation’s long-term funding at December 31, 2016 . Year ($ in Thousands) 2017 $ 5 2018 1,865,000 2019 498,939 2020 164 2021 150,000 Thereafter 247,687 Total long-term funding $ 2,761,795

Stockholders' Equity

Stockholders' Equity	12 Months Ended
	Dec. 31, 2016
Equity [Abstract]
Stockholders' Equity	Stockholders' Equity Preferred Equity : In September 2011, the Corporation issued 2,600,000 depositary shares, each representing a 1/40th interest in a share of the Corporation’s 8.00% Non-Cumulative Perpetual Preferred Stock, Series B, liquidation preference $1,000 per share (the “Series B Preferred Stock”). Dividends on the Series B Preferred Stock were payable quarterly in arrears only when, as and if declared by the Board of Directors at a rate per annum equal to 8.00% . Shares of the Series B Preferred Stock had priority over the Corporation’s common stock with regard to the payment of dividends and distributions upon liquidation, dissolution or winding up. As such, the Corporation could not pay dividends on or repurchase, redeem, or otherwise acquire for consideration shares of its common stock unless dividends for the Series B Preferred Stock had been declared for that period, and sufficient funds had been set aside to make payment. The Series B Preferred Stock was redeemable by the Corporation at its option (i) either in whole or in part, from time to time, on any dividend payment date on or after the dividend payment date occurring on September 15, 2016 , or (ii) in whole but not in part, at any time within 90 days following certain regulatory capital treatment events, in each case at a redemption price of $1,000 per share (equivalent to $25 per depositary share), plus any applicable dividends. Except in certain limited circumstances, the Series B Preferred Stock did not have any voting rights. On July 23, 2013 , the Board of Directors authorized the purchase of up to $10 million of the Corporation’s Series B Preferred Stock. During 2015 , the Corporation repurchased approximately 50,000 depositary shares for $1 million . On September 15, 2016 , the Corporation redeemed all remaining depositary shares for $59 million . In June 2015, the Corporation issued 2,600,000 depositary shares, each representing a 1/40th interest in a share of the Corporation’s 6.125% Non-Cumulative Perpetual Preferred Stock, Series C, liquidation preference $1,000 per share (the “Series C Preferred Stock”). Dividends on the Series C Preferred Stock are payable quarterly in arrears only when, as and if declared by the Board of Directors at a rate per annum equal to 6.125% . Shares of the Series C Preferred Stock have priority over the Corporation’s common stock with regard to the payment of dividends and distributions upon liquidation, dissolution or winding up. As such, the Corporation may not pay dividends on or repurchase, redeem, or otherwise acquire for consideration shares of its common stock unless dividends for the Series C Preferred Stock have been declared for that period, and sufficient funds have been set aside to make payment. The Series C Preferred Stock may be redeemed by the Corporation at its option (i) either in whole or in part, from time to time, on any dividend payment date on or after the dividend payment date occurring on June 15, 2020 , or (ii) in whole but not in part, at any time within 90 days following certain regulatory capital treatment events, in each case at a redemption price of $1,000 per share (equivalent to $25 per depositary share), plus any applicable dividends. Except in certain limited circumstances, the Series C Preferred Stock does not have any voting rights. On August 28, 2015 , the Board of Directors authorized the repurchase of up to $10 million of the Series C Preferred Stock. The Corporation has not repurchased any of the Series C Preferred Stock under this authorization. As of December 31, 2016 , $10 million remained available under this repurchase authorization. In September 2016, the Corporation issued 4,000,000 depositary shares, each representing a 1/40th interest in a share of the Corporation’s 5.375% Non-Cumulative Perpetual Preferred Stock, Series D, liquidation preference $1,000 per share (the “Series D Preferred Stock”). Dividends on the Series D Preferred Stock are payable quarterly in arrears only when, as and if declared by the Board of Directors at a rate per annum equal to 5.375% . Shares of the Series D Preferred Stock have priority over the Corporation’s common stock with regard to the payment of dividends and distributions upon liquidation, dissolution or winding up. As such, the Corporation may not pay dividends on or repurchase, redeem, or otherwise acquire for consideration shares of its common stock unless dividends for the Series D Preferred Stock have been declared for that period, and sufficient funds have been set aside to make payment. The Series D Preferred Stock may be redeemed by the Corporation at its option (i) either in whole or in part, from time to time, on any dividend payment date on or after the dividend payment date occurring on September 15, 2021 , or (ii) in whole but not in part, at any time within 90 days following certain regulatory capital treatment events, in each case at a redemption price of $1,000 per share (equivalent to $25 per depositary share), plus any applicable dividends. Except in certain limited circumstances, the Series D Preferred Stock does not have any voting rights. Common Stock Warrants: In November 2008, under the Capital Purchase Program, the Corporation issued a 10-year warrant to purchase approximately 4 million shares of common stock. The Common Stock Warrants have a term of 10 years and are exercisable at any time, in whole or in part, at an exercise price of $19.77 per share (subject to certain anti-dilution adjustments). On December 6, 2011 , the U.S. Department of Treasury closed an underwritten secondary public offering of the warrants, each representing the right to purchase one share of common stock, par value $0.01 per share, of the Corporation. The public offering price and the allocation of the warrants in the secondary public warrant offering by the U.S. Treasury were determined by an auction process and the Corporation received no proceeds from the public offering. Subsidiary Equity: At December 31, 2016 , subsidiary equity equaled $3.2 billion . See Note 19 for additional information on regulatory requirements for the Bank. Stock Repurchases: The Board of Directors authorized the repurchase of common stock during 2015 . During 2016 , the Corporation repurchased 1 million shares for $20 million (or an average cost per common share of $17.10 ), all of which were returned to authorized but unissued shares. During 2015 , the Corporation repurchased 5 million shares for $93 million (or an average cost per common share of $18.73 ) all of which were returned to authorized but unissued shares. The Corporation also repurchased shares for minimum tax withholding settlements on equity compensation totaling approximately $5 million ( 293,000 shares at an average cost per common share of $17.30 ) during 2016 compared to repurchases of shares for minimum tax withholding settlements on equity compensation totaling approximately $5 million ( 285,000 shares at an average cost per common share of $17.87 ) for 2015 . As of December 31, 2016, approximately $88 million remained available to repurchase shares of common stock under previously approved Board of Director authorizations. 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. Other Comprehensive Income (Loss): See the Consolidated Statements of Comprehensive Income for a summary of activity in other comprehensive income (loss) and see Note 22 for a summary of the components of accumulated other comprehensive income (loss).

Stock-Based Compensation

Stock-Based Compensation	12 Months Ended
	Dec. 31, 2016
Compensation and Retirement Disclosure [Abstract]
Stock-Based Compensation	Stock-Based Compensation Stock-Based Compensation Plan: In March 2013, the Board of Directors, with subsequent approval of the Corporation’s shareholders, approved the adoption of the 2013 Incentive Compensation Plan (“2013 Plan”). As of December 31, 2016 , approximately 7 million shares remained available for grant under the 2013 Plan. Under the 2013 Plan, options are generally exercisable up to 10 years from the date of grant, have an exercise price that is equal to the closing price of the Corporation’s stock on the grant date, and vest ratably over four years . The Corporation also issues restricted common stock and restricted common stock units to certain key employees (collectively referred to as “restricted stock awards”) under the 2013 Plan. The shares of restricted stock are restricted as to transfer, but are not restricted as to dividend payment or voting rights. Restricted stock units receive dividend equivalents but do not have voting rights. The transfer restrictions lapse over three or four years, depending upon whether the awards are performance-based or service-based. Performance-based awards are based on earnings per share performance goals, relative total shareholder return, and continued employment or meeting the requirements for retirement and service-based awards are contingent upon continued employment or meeting the requirements for retirement. Performance-based restricted stock awards vest over the three year performance period and service-based restricted stock awards vest ratably over four years. The 2013 Plan provides that restricted stock awards and stock options will immediately become fully vested upon retirement from the Corporation of those colleagues whose retirement meets the early retirement or normal retirement definitions under the plan (“retirement eligible colleagues”). See Note 1 for the Corporation’s accounting policy for stock based compensation. Accounting for Stock-Based Compensation: 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 2016 , 2015 and 2014 . 2016 2015 2014 Dividend yield 2.50 % 2.00 % 2.00 % Risk-free interest rate 2.00 % 2.00 % 2.00 % Weighted average expected volatility 25.00 % 20.00 % 20.00 % Weighted average expected life 5.5 years 6 years 6 years Weighted average per share fair value of options $3.36 $3.08 $3.00 A summary of the Corporation’s stock option activity for the year ended December 31, 2016 is presented below. Stock Options Shares Weighted Average Exercise Price Weighted Average Remaining Contractual Term Aggregate Intrinsic Value (000s) Outstanding at December 31, 2015 6,629,143 $ 17.22 6.24 $ 18,730 Granted 1,302,298 17.45 Exercised (1,389,146 ) 14.81 Forfeited or expired (184,452 ) 21.62 Outstanding at December 31, 2016 6,357,843 $ 17.67 6.10 $ 47,902 Options Exercisable at December 31, 2016 3,632,749 $ 17.85 4.45 $ 28,109 The following table summarizes information about the Corporation’s nonvested stock option activity for the year ended December 31, 2016. Nonvested Stock Options Shares Weighted Average Nonvested at December 31, 2015 2,438,898 $ 3.15 Granted 1,302,298 3.36 Vested (909,361 ) 3.27 Forfeited (106,741 ) 3.39 Nonvested at December 31, 2016 2,725,094 $ 3.21 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 years ended December 31, 2016 , 2015 , and 2014 the intrinsic value of stock options exercised was $9 million , $7 million , and $4 million , respectively. The total fair value of stock options that vested was $3 million , $6 million and $7 million , respectively, for the years ended December 31, 2016 , 2015 , and 2014 . For the years ended December 31, 2016 , 2015 , and 2014 , the Corporation recognized compensation expense of $4 million , $4 million , and $6 million respectively, for the vesting of stock options. Included in compensation expense for 2016 was approximately $940,000 of expense for the accelerated vesting of stock options granted to retirement eligible colleagues. At December 31, 2016 , the Corporation had $5 million of unrecognized compensation expense related to stock options that is expected to be recognized over the remaining requisite service periods that extend predominantly through the fourth quarter 2019 . The following table summarizes information about the Corporation’s restricted stock activity for the year ended December 31, 2016. Restricted Stock Shares Weighted Average Grant Date Fair Value Outstanding at December 31, 2015 2,250,028 $ 17.03 Granted 1,095,596 17.58 Vested (864,617 ) 16.62 Forfeited (103,627 ) 17.59 Outstanding at December 31, 2016 2,377,380 $ 17.40 The Corporation amortizes the expense related to restricted stock awards as compensation expense over the vesting period specified in the grant. Expense for restricted stock awards of approximately $18 million , $15 million , and $10 million was recorded for the years ended December 31, 2016 , 2015 , and 2014 , respectively. Included in compensation expense for 2016 was approximately $3 million of expense for the accelerated vesting of restricted stock awards granted to retirement eligible colleagues. The Corporation had $20 million of unrecognized compensation costs related to restricted stock awards at December 31, 2016 , that is expected to be recognized over the remaining requisite service periods that extend predominantly through fourth quarter 2019 . 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. As described in Note 10 , the Board of Directors has authorized management to repurchase shares of the Corporation’s common stock each quarter 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.

Retirement Plans

Retirement Plans	12 Months Ended
	Dec. 31, 2016
Defined Benefit Pension Plans and Defined Benefit Postretirement Plans Disclosure [Abstract]
Retirement Plans	Retirement Plan 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 provided healthcare access for eligible retired employees in its Postretirement Plan (the “Postretirement Plan”). The Postretirement Plan was frozen during 2016. The Corporation has no plan assets attributable to the Postretirement Plan. The Corporation reserves the right to make changes to the Postretirement Plan at any time. The funded status and amounts recognized in the 2016 and 2015 consolidated balance sheets, as measured on December 31, 2016 and 2015 , respectively, for the Retirement Account and Postretirement Plans were as follows. Retirement Account Plan Postretirement Plan Retirement Account Plan Postretirement Plan 2016 2016 2015 2015 ($ in Thousands) Change in Fair Value of Plan Assets Fair value of plan assets at beginning of year $ 289,599 $ — $ 303,496 $ — Actual return on plan assets 17,097 — 495 — Employer contributions — 248 — 264 Gross benefits paid (10,978 ) (248 ) (14,392 ) (264 ) Fair value of plan assets at end of year* $ 295,718 $ — $ 289,599 $ — Change in Benefit Obligation Net benefit obligation at beginning of year $ 171,783 $ 3,436 $ 171,333 $ 3,578 Service cost 6,780 — 11,257 — Interest cost 7,121 142 6,617 141 Plan amendments (823 ) (936 ) — — Actuarial (gain) loss 2,942 9 (3,032 ) (19 ) Gross benefits paid (10,978 ) (248 ) (14,392 ) (264 ) Net benefit obligation at end of year* $ 176,825 $ 2,403 $ 171,783 $ 3,436 Funded (unfunded) status $ 118,893 $ (2,403 ) $ 117,816 $ (3,436 ) Noncurrent assets 118,893 — 117,816 — Current liabilities — (215 ) — (274 ) Noncurrent liabilities — (2,188 ) — (3,162 ) Asset (Liability) Recognized in the Consolidated Balance Sheets $ 118,893 $ (2,403 ) $ 117,816 $ (3,436 ) * The fair value of the plan assets represented 167% and 169% of the net benefit obligation of the pension plan at December 31, 2016 and 2015 , respectively. Amounts recognized in accumulated other comprehensive loss, net of tax, as of December 31, 2016 and 2015 follow. Retirement Account Plan Postretirement Plan Retirement Account Plan Postretirement Plan 2016 2016 2015 2015 ($ in Thousands) Prior service cost $ (342 ) $ (580 ) $ 122 $ — Net actuarial loss 35,443 79 32,879 73 Amount not yet recognized in net periodic benefit cost, but recognized in accumulated other comprehensive loss $ 35,101 $ (501 ) $ 33,001 $ 73 Other changes in plan assets and benefit obligations recognized in other comprehensive income (loss) (“OCI”), net of tax, in 2016 and 2015 were as follows. Retirement Account Postretirement Retirement Account Postretirement 2016 2016 2015 2015 ($ in Thousands) Net gain (loss) $ (6,132 ) $ (9 ) $ (17,911 ) $ 19 Amortization of prior service cost (73 ) — 50 — Amortization of actuarial gain 2,115 — 2,256 — Plan amendments 823 936 — — Income tax (expense) benefit 1,168 (353 ) 5,880 (7 ) Total Recognized in OCI $ (2,099 ) $ 574 $ (9,725 ) $ 12 The components of net periodic benefit cost for the Retirement Account Plan and Postretirement Plans for 2016 , 2015 , and 2014 were as follows. Retirement Account Postretirement Retirement Account Postretirement Retirement Account Postretirement 2016 2016 2015 2015 2014 2014 ($ in Thousands) Service cost $ 6,780 $ — $ 11,257 $ — $ 11,058 $ — Interest cost 7,121 142 6,617 141 7,132 150 Expected return on plan assets (20,287 ) — (21,438 ) — (19,922 ) — Amortization of: Prior service cost (73 ) — 50 — 58 — Actuarial (gain) loss 2,115 — 2,256 — 1,384 (35 ) Total net pension cost $ (4,344 ) $ 142 $ (1,258 ) $ 141 $ (290 ) $ 115 As of December 31, 2016 , the estimated actuarial losses and prior service cost that will be amortized during 2017 from accumulated other comprehensive income into net periodic benefit cost for the Retirement Account Plan include expense of $2 million for actuarial losses and income of $0.1 million for the prior service cost. For the Postretirement Plan, the estimated prior service cost that will be amortized during 2017 from accumulated other comprehensive income into periodic net benefit cost was income of $0.1 million . Retirement Account Plan Postretirement Plan Retirement Account Plan Postretirement Plan 2016 2016 2015 2015 Weighted average assumptions used to determine benefit obligations: Discount rate 4.10 % 4.10 % 4.30 % 4.30 % Rate of increase in compensation levels 4.00 % NA 4.00 % NA Weighted average assumptions used to determine net periodic benefit costs: Discount rate 4.30 % 4.30 % 4.00 % 4.00 % Rate of increase in compensation levels 4.00 % NA 4.00 % NA Expected long-term rate of return on plan assets 7.00 % NA 7.50 % NA The overall expected long-term rates of return on the Retirement Account Plan assets were 7.00% for 2016 and 7.50% for 2015 , respectively. The expected long-term (more than 20 years) rate of return was estimated using market benchmarks for equities and bonds applied to the Retirement Account Plan’s anticipated asset allocations. The expected return on equities was computed utilizing a valuation framework, which projected future returns based on current equity valuations rather than historical returns. The actual rate of return for the Retirement Account Plan assets was 6.36% and 0.43% for 2016 and 2015 , respectively. The Retirement Account Plan’s investments are exposed to various risks, such as interest rate, market, and credit risks. Due to the level of risks associated with certain investments and the level of uncertainty related to changes in the value of the investments, it is at least reasonably possible that changes in risks in the near term could materially affect the amounts reported. The investment objective for the Retirement Account Plan is to maximize total return with a tolerance for average risk. The plan has a diversified portfolio designed to provide liquidity, current income, and growth of income and principal, with anticipated asset allocation ranges of: equity securities 50 - 70% , fixed income securities 30 - 50% , other cash equivalents 0 - 5% , and alternative securities 0 - 15% . Based on changes in economic and market conditions, the Corporation could be outside of the allocation ranges for brief periods of time. The asset allocation for the Retirement Account Plan as of the December 31, 2016 and 2015 measurement dates, respectively, by asset category were as follows. Asset Category 2016 2015 Equity securities 60 % 60 % Fixed income securities 39 % 40 % Other 1 % — % Total 100 % 100 % The Retirement Account Plan assets include cash equivalents, such as money market accounts, mutual funds, and common / collective trust funds (which include investments in equity and bond securities). Money market accounts are stated at cost plus accrued interest, mutual funds are valued at quoted market prices and investments in common / collective trust funds are valued at the amount at which units in the funds can be withdrawn. Based on these inputs, the following table summarizes the fair value of the Retirement Account Plan’s investments as of December 31, 2016 and 2015 . Fair Value Measurements Using December 31, 2016 Level 1 Level 2 Level 3 ($ in Thousands) Retirement Account Plan Investments: Money market account $ 3,624 $ 3,624 $ — $ — Common /collective trust funds 126,741 126,741 — — Mutual funds 165,353 165,353 — — Total Retirement Account Plan Investments $ 295,718 $ 295,718 $ — $ — Fair Value Measurements Using December 31, 2015 Level 1 Level 2 Level 3 ($ in Thousands) Retirement Account Plan Investments: Money market account $ 481 $ 481 $ — $ — Common /collective trust funds 120,136 120,136 — — Mutual funds 168,982 168,982 — — Total Retirement Account Plan Investments $ 289,599 $ 289,599 $ — $ — The Corporation’s funding policy is to pay at least the minimum amount required by the funding requirements of federal law and regulations, with consideration given to the maximum funding amounts allowed. The Corporation regularly reviews the funding of its Retirement Account Plan. The projected benefit payments for the Retirement Account and Postretirement Plans at December 31, 2016 , reflecting expected future services, were as follows. The projected benefit payments were calculated using the same assumptions as those used to calculate the benefit obligations listed above. Retirement Account Plan Postretirement Plan ($ in Thousands) Estimated future benefit payments: 2017 $ 14,829 $ 215 2018 14,538 199 2019 14,169 179 2020 13,815 177 2021 13,651 174 2022-2026 71,433 815 The health care trend rate is an assumption as to how much the Postretirement Plan’s medical costs will increase each year in the future. The health care trend rate assumption for pre-65 coverage is 8.0% for 2016 , and 0.5% - 0.25% lower in each succeeding year, to an ultimate rate of 5% for 2024 and future years. The health care trend rate assumption for post-65 coverage is 7.5% for 2016 , and 0.5% - 0.25% lower in each succeeding year, to an ultimate rate of 5% for 2023 and future years. A one percentage point change in the assumed health care cost trend rate would have the following effect. 2016 2015 100 bp Increase 100 bp Decrease 100 bp Increase 100 bp Decrease ($ in Thousands) Effect on total of service and interest cost $ 7 $ (6 ) $ 15 $ (13 ) Effect on postretirement benefit obligation $ 173 $ (149 ) $ 357 $ (310 ) The Corporation also has a 401(k) and Employee Stock Ownership Plan (the “401(k) plan”). The Corporation’s contribution is determined by the Compensation and Benefits Committee of the Board of Directors. Total expense related to contributions to the 401(k) plan was $14 million , $11 million , and $10 million in 2016 , 2015 , and 2014 , respectively.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes The current and deferred amounts of income tax expense (benefit) were as follows. Years Ended December 31, 2016 2015 2014 ($ in Thousands) Current: Federal $ 73,781 $ 82,449 $ 74,646 State 2,885 2,560 1,000 Total current 76,666 85,009 75,646 Deferred: Federal 3,338 (10,606 ) (805 ) State 7,318 7,084 10,695 Total deferred 10,656 (3,522 ) 9,890 Total income tax expense $ 87,322 $ 81,487 $ 85,536 Temporary differences between the amounts reported in the financial statements and the tax bases of assets and liabilities resulted in deferred taxes. Deferred tax assets and liabilities at December 31 were as follows. 2016 2015 ($ in Thousands) Deferred tax assets: Allowance for loan losses $ 100,891 $ 106,258 Allowance for other losses 11,080 10,906 Accrued liabilities 5,969 6,802 Deferred compensation 33,169 31,677 State net operating losses 7,882 14,154 Nonaccrual interest 1,085 1,901 Net unrealized losses on available-for-sale securities 16,980 219 Net unrealized losses on pension and postretirement benefits 21,218 20,404 Other 8,128 5,811 Total deferred tax assets 206,402 198,132 Deferred tax liabilities: FHLB stock dividends — 2,165 Prepaid expenses 70,943 69,396 Goodwill 27,365 25,770 Mortgage banking activities 17,569 15,704 Deferred loan fee income 16,474 17,770 State deferred taxes 3,800 6,366 Lease financing 1,975 3,042 Bank premises and equipment 7,698 7,491 Other 8,594 9,062 Total deferred tax liabilities 154,418 156,766 Net deferred tax assets $ 51,984 $ 41,366 At December 31, 2016 and 2015 , there was no valuation allowance for deferred tax assets. Management has determined that it is more likely than not that these assets could be realized through carry back to taxable income in prior years, future reversals of existing taxable temporary differences and future taxable income. This conclusion is based on the Corporation's historical earnings, its current level of earnings and prospects for continued growth and profitability. At December 31, 2016 , the Corporation had state net operating loss carryforwards of $100 million (of which, $16 million was acquired from various acquisitions) that will begin expiring in 2032 . The effective income tax rate differs from the statutory federal tax rate. The major reasons for this difference were as follows. 2016 2015 2014 Federal income tax rate at statutory rate 35.0 % 35.0 % 35.0 % Increases (decreases) resulting from: Tax-exempt interest and dividends (4.8 )% (5.0 )% (4.6 )% State income taxes (net of federal benefit) 2.3 % 2.3 % 2.8 % Bank owned life insurance (1.7 )% (1.2 )% (1.7 )% Tax effect of tax credits and benefits, net of related expenses (0.8 )% (0.5 )% (1.4 )% Tax reserve adjustments 0.3 % (0.6 )% 0.7 % Other 0.1 % 0.2 % 0.2 % Effective income tax rate 30.4 % 30.2 % 31.0 % Savings banks acquired by the Corporation in 1997 and 2004 qualified under provisions of the Internal Revenue Code that permitted them to deduct from taxable income an allowance for bad debts that differed from the provision for such losses charged to income for financial reporting purposes. Accordingly, no provision for income taxes has been made for $100 million of retained income at December 31, 2016 . If income taxes had been provided, the deferred tax liability would have been approximately $40 million . Management does not expect this amount to become taxable in the future, therefore, no provision for income taxes has been made. The Corporation and its subsidiaries file income tax returns in the U.S. federal jurisdiction and various state jurisdictions. The Corporation’s federal income tax returns are open and subject to examination from the 2013 tax return year and forward. The years open to examination by state and local government authorities varies by jurisdiction. A reconciliation of the beginning and ending amount of unrecognized tax benefits was as follows. 2016 2015 ($ in Millions) Balance at beginning of year $ 9 $ 9 Subtractions for tax positions related to prior years — (2 ) Additions for tax positions related to current year 1 2 Balance at end of year $ 10 $ 9 At December 31, 2016 and 2015 , the total amount of unrecognized tax benefits that, if recognized, would affect the effective tax rate was $7 million and $6 million , respectively. The Corporation recognizes interest and penalties accrued related to unrecognized tax benefits in the income tax expense line of the consolidated statements of income. Interest and penalty expense (benefit) was $0 and $(1) million , as of December 31, 2016 and 2015 , respectively. At December 31, 2016 and 2015 , accrued interest and penalties was $2 million . Management does not anticipate significant adjustments to the total amount of unrecognized tax benefits within the next twelve months.

Derivative and Hedging Activiti

Derivative and Hedging Activities	12 Months Ended
	Dec. 31, 2016
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 $40 million of investment securities as collateral at December 31, 2016 , and pledged $9 million of investment securities as collateral at December 31, 2015 . 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 December 31, 2016 , the Corporation posted no cash collateral for the margin, compared to $22 million at December 31, 2015 . The Corporation’s derivative and hedging instruments are recorded at fair value on the consolidated balance sheets. The fair value of the Corporation’s interest rate-related 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 18 for additional fair value information and disclosures and see Note 1 for the Corporation's accounting policy for derivative and hedging activities. Derivatives to Accommodate Customer Needs The Corporation enters into various derivative contracts which are not designated as hedging instruments. Such derivative products are entered into primarily for the benefit of commercial customers seeking to manage their exposures to interest rate, foreign currency, and commodity price risks. 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 15 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 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 risk management 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. Such foreign currency exchange contracts are carried at fair value on the consolidated balance sheets with changes in fair value recorded as a component of capital market fees, net. Commodity contracts: The Corporation provides commodity risk management services to commercial customers, exclusively oil and gas 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. Commodity contracts are carried at fair value on the consolidated balance sheets with changes in fair value recorded as a component of capital market fees, net. The table below identifies the balance sheet category and fair values of the Corporation’s derivative instruments to accommodate customer needs which are not designated as hedging instruments. December 31, 2016 December 31, 2015 Notional Amount Fair Value Balance Sheet Category Notional Amount Fair Balance Sheet ($ in Thousands) Interest rate-related instruments — customer and mirror $ 2,039,323 $ 33,671 Trading assets $ 1,665,965 $ 29,391 Trading assets Interest rate-related instruments — customer and mirror 2,039,323 (33,188 ) Trading liabilities 1,665,965 (30,886 ) Trading liabilities Foreign currency exchange forwards 109,675 2,002 Trading assets 72,976 1,532 Trading assets Foreign currency exchange forwards 106,251 (1,943 ) Trading liabilities 65,649 (1,398 ) Trading liabilities Commodity contracts 127,582 16,725 Trading assets 44,380 1,269 Trading assets Commodity contracts 128,368 (15,972 ) Trading liabilities 44,256 (1,146 ) 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. December 31, 2016 December 31, 2015 Notional Amount Fair Balance Sheet Notional Amount Fair Balance Sheet ($ in Thousands) Interest rate lock commitments (mortgage) $ 285,345 $ 206 Other assets $ 271,530 $ 958 Other assets Forward commitments (mortgage) 179,600 2,908 Other assets 231,798 403 Other assets Purchased options (time deposit) 80,554 2,576 Other assets 104,582 2,715 Other assets Written options (time deposit) 80,554 (2,576 ) Other liabilities 104,582 (2,715 ) 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 Year Ended December 31, 2016 2015 ($ in Thousands) Interest rate-related instruments — customer and mirror, net Capital market fees, net $ 1,978 $ 854 Interest rate lock commitments (mortgage) Mortgage banking, net (752 ) (989 ) Forward commitments (mortgage) Mortgage banking, net 2,505 2,838 Foreign currency exchange forwards Capital market fees, net (75 ) (49 ) Commodity contracts Capital market fees, net 630 123

Balance Sheet Offsetting

Balance Sheet Offsetting	12 Months Ended
	Dec. 31, 2016
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 14 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 8 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) 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 December 31, 2015 Derivative assets: Interest and commodity agreements $ 1,466 $ — $ 1,466 $ (1,466 ) $ — $ — Derivative liabilities: Interest and commodity agreements $ 30,200 $ — $ 30,200 $ (1,466 ) $ (28,734 ) $ —

Commitments, Off-Balance Sheet

Commitments, Off-Balance Sheet Arrangements, and Contingent Liabilities	12 Months Ended
	Dec. 31, 2016
Commitments and Contingencies Disclosure [Abstract]
Commitments, Off-Balance Sheet Arrangements, and Contingent Liabilities	Commitments, Off-Balance Sheet Arrangements, and Legal Proceedings 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 14 ). The following is a summary of lending-related commitments. 2016 2015 ($ in Thousands) Commitments to extend credit, excluding commitments to originate residential mortgage loans held for sale (1)(2) $ 8,131,131 $ 7,402,518 Commercial letters of credit (1) 7,923 9,945 Standby letters of credit (3) 259,632 296,508 (1) 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 December 31, 2016 and 2015 . (2) Interest rate lock commitments to originate residential mortgage loans held for sale are considered derivative instruments and are disclosed in Note 14 . (3) The Corporation has established a liability of $3 million at both December 31, 2016 and December 31, 2015 , 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 December 31, 2016 compared to $24 million at December 31, 2015 , and is included in accrued expenses and other liabilities on the consolidated balance sheets. See Note 1 for the Corporation’s accounting policy on the allowance for unfunded commitments. See Note 4 for additional information on the allowance for unfunded commitments. 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 14 . 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 December 31, 2016 , was $85 million , compared to $52 million at December 31, 2015 , included in other assets on the consolidated balance sheets. Related to these investments, the Corporation had remaining commitments to fund of $69 million at December 31, 2016 , and $61 million at December 31, 2015 . Contingent Liabilities and 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 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, and the case was dismissed with prejudice. The plaintiff has appealed this decision to the U.S. Court of Appeals for the Eighth Circuit. 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. 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. A variety of consumer products, including legacy debt protection and identity protection products provided by third parties, and mortgage and deposit products, and certain fees and charges related to such products, including overdraft and similar fees, have come under increased regulatory scrutiny by the CFPB, the OCC, and state attorneys general. 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 and the fees and other charges related thereto. 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. 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. 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 $2 million and $3 million during the years ended December 31, 2016 and 2015 , respectively. The loss reimbursement and settlement claims paid for the years ended December 31, 2016 and 2015 , respectively, were negligible. Make whole requests during 2015 and 2016 generally arose from loans sold during the period of January 1, 2012 to December 31, 2016 , which totaled $9.2 billion at the time of sale, and consisted primarily of loans sold to GSEs. As of December 31, 2016 , approximately $6.1 billion of these sold loans remain outstanding. The balance in the mortgage repurchase reserve at the balance sheet date reflects the estimated amount of potential loss the Corporation could incur from repurchasing a loan, as well as loss reimbursements, indemnifications, and other settlement resolutions. The following summarizes the changes in the mortgage repurchase reserve for the years ended as follows. 2016 2015 ($ in Thousands) Balance at beginning of year $ 1,197 $ 3,258 Repurchase provision expense 456 428 Adjustments to provision expense (750 ) (2,450 ) Charge offs, net (3 ) (39 ) Balance at end of year $ 900 $ 1,197 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 December 31, 2016 , and December 31, 2015 , there were approximately $62 million and $68 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 December 31, 2016 and December 31, 2015 , there were $98 million and $132 million , respectively, of such residential mortgage loans with credit risk recourse, upon which there have been negligible historical losses to the Corporation.

Parent Company Only Financial I

Parent Company Only Financial Information	12 Months Ended
	Dec. 31, 2016
Condensed Financial Information of Parent Company Only Disclosure [Abstract]
Parent Company Only Financial Information	Parent Company Only Financial Information Presented below are condensed financial statements for the Parent Company. BALANCE SHEETS December 31, 2016 2015 ($ in Thousands) ASSETS Cash and due from banks $ 402,786 $ 610,862 Investment securities available for sale, at fair value 14,389 61,847 Investment in subsidiaries 3,248,763 3,211,685 Other assets 61,242 70,595 Total assets $ 3,727,180 $ 3,954,989 LIABILITIES AND STOCKHOLDERS’ EQUITY Commercial paper $ 101,688 $ 67,978 Senior notes, at par 250,000 680,000 Subordinated notes, at par 250,000 250,000 Long-term funding capitalized costs (3,393 ) (4,061 ) Total long-term funding 496,607 925,939 Accrued expenses and other liabilities 37,573 23,826 Total liabilities 635,868 1,017,743 Preferred equity 159,929 121,379 Common equity 2,931,383 2,815,867 Total stockholders’ equity 3,091,312 2,937,246 Total liabilities and stockholders’ equity $ 3,727,180 $ 3,954,989 STATEMENTS OF INCOME For the Years Ended December 31, 2016 2015 2014 ($ in Thousands) INCOME Dividends from subsidiaries $ 188,000 $ 205,000 $ 223,000 Interest income on notes receivable — — 1,264 Other income 4,669 8,441 9,713 Total income 192,669 213,441 233,977 EXPENSE Interest expense on short and long-term funding 21,901 39,576 24,847 Other expense 4,289 4,684 776 Total expense 26,190 44,260 25,623 Income before income tax expense (benefit) and equity in undistributed net income (loss) of subsidiaries 166,479 169,181 208,354 Income tax expense (benefit) 3,468 (1,665 ) (5,801 ) Income before equity in undistributed net income (loss) of subsidiaries 163,011 170,846 214,155 Equity in undistributed net income (loss) of subsidiaries 37,263 17,455 (23,646 ) Net income 200,274 188,301 190,509 Preferred stock dividends 8,903 7,155 5,002 Net income available to common equity $ 191,371 $ 181,146 $ 185,507 STATEMENTS OF CASH FLOWS For the Years Ended December 31, 2016 2015 2014 ($ in Thousands) OPERATING ACTIVITIES Net income $ 200,274 $ 188,301 $ 190,509 Adjustments to reconcile net income to net cash provided by operating activities: (Increase) decrease in equity in undistributed net income of subsidiaries (37,263 ) (17,455 ) 23,646 Gain on sales of investment securities, net (466 ) — (214 ) Asset gain, net (793 ) (5,673 ) (5,609 ) Net change in other assets and other liabilities 19,708 (10,997 ) (14,022 ) Net cash provided by operating activities 181,460 154,176 194,310 INVESTING ACTIVITIES Proceeds from sales of investment securities 47,719 13,962 88,844 Net decrease in notes receivable — — 46,594 Purchase of other assets, net of disposals 2,211 11,964 10,930 Net cash provided by investing activities 49,930 25,926 146,368 FINANCING ACTIVITIES Net increase (decrease) in short-term funding 33,710 (6,319 ) 8,813 Repayment of long-term funding (430,000 ) — (155,000 ) Proceeds from issuance of long-term funding — — 496,030 Proceeds from issuance of common stock for stock-based compensation plans 21,748 20,054 13,228 Proceeds from issuance of preferred stock 97,066 62,966 — Redemption of preferred stock (58,903 ) — — Purchase of preferred stock (1,248 ) (1,335 ) (2,451 ) Purchase of common stock returned to authorized but unissued (20,007 ) (93,000 ) (150,498 ) Purchase of treasury stock — — (108,600 ) Purchase of treasury stock for tax withholding (5,074 ) (5,154 ) (3,712 ) Cash dividends on common stock (67,855 ) (62,400 ) (58,710 ) Cash dividends on preferred stock (8,903 ) (7,155 ) (5,002 ) Net cash provided by (used in) financing activities (439,466 ) (92,343 ) 34,098 Net increase (decrease) in cash and cash equivalents (208,076 ) 87,759 374,776 Cash and cash equivalents at beginning of year 610,862 523,103 148,327 Cash and cash equivalents at end of year $ 402,786 $ 610,862 $ 523,103

Regulatory Matters

Regulatory Matters	12 Months Ended
	Dec. 31, 2016
Regulatory Capital Requirements [Abstract]
Regulatory Matters	Regulatory Matters Restrictions on Cash and Due From Banks The Corporation’s bank subsidiary is required to maintain certain vault cash and reserve balances with the Federal Reserve Bank to meet specific reserve requirements. These requirements approximated $115 million at December 31, 2016 . Regulatory Capital Requirements The Corporation and its subsidiary bank are subject to various regulatory capital requirements administered by the federal banking agencies. Failure to meet minimum capital requirements can initiate certain mandatory and possible additional discretionary actions by regulators that, if undertaken, could have a direct material effect on the Corporation’s financial statements. Under capital adequacy guidelines and the regulatory framework for prompt corrective action, the Corporation must meet specific capital guidelines that involve quantitative measures of the Corporation’s assets, liabilities, and certain off-balance sheet items as calculated under regulatory accounting practices. The Corporation’s capital amounts and classification are also subject to qualitative judgments by the regulators about components, risk weightings, and other factors. Quantitative measures established by regulation to ensure capital adequacy require the Corporation to maintain minimum amounts and ratios (set forth in the table below) of total and Common equity Tier 1 capital (as defined in the regulations) to risk-weighted assets (as defined), and of Tier 1 capital (as defined) to average assets (as defined). Management believes, as of December 31, 2016 and 2015 , that the Corporation meets all capital adequacy requirements to which it is subject. For additional information on the capital requirements applicable for the Corporation and the Bank, please see Part I, Item 1. As of December 31, 2016 and 2015 , the most recent notifications from the Office of the Comptroller of the Currency and the Federal Deposit Insurance Corporation categorized the subsidiary bank as well capitalized under the regulatory framework for prompt corrective action. To be categorized as well capitalized, the subsidiary bank must maintain minimum ratios as set forth in the table. There are no conditions or events since that notification that management believes have changed the institution’s category. The actual capital amounts and ratios of the Corporation and its significant subsidiary are presented below. No deductions from capital were made for interest rate risk in 2016 or 2015 . Actual For Capital Adequacy Purposes To Be Well Capitalized Under Prompt Corrective Action Provisions: (2) Amount Ratio (1) Amount Ratio (1) Amount Ratio (1) ($ in Thousands) As of December 31 , 2016 Associated Banc-Corp Total capital $ 2,706,760 12.68 % $ 1,707,276 ≥ 8.00 % Tier 1 capital 2,191,798 10.27 1,280,457 ≥ 6.00 % Common equity Tier 1 capital 2,032,587 9.52 960,343 ≥ 4.50 % Leverage 2,191,798 7.83 1,119,685 ≥ 4.00 % Associated Bank, N.A. Total capital $ 2,565,062 12.07 % $ 1,700,737 ≥ 8.00 % $ 2,125,921 ≥ 10.00 % Tier 1 capital 2,298,812 10.81 1,275,553 ≥ 6.00 % 1,700,737 ≥ 8.00 % Common equity Tier 1 capital 2,098,812 9.87 956,664 ≥ 4.50 % 1,381,849 ≥ 6.50 % Leverage 2,298,812 8.24 1,115,731 ≥ 4.00 % 1,394,663 ≥ 5.00 % As of December 31 , 2015 Associated Banc-Corp Total capital $ 2,515,861 12.62 % $ 1,594,397 ≥ 8.00 % Tier 1 capital 2,016,861 10.12 1,195,798 ≥ 6.00 % Common equity Tier 1 capital 1,897,944 9.52 896,848 ≥ 4.50 % Leverage 2,016,861 7.60 1,061,325 ≥ 4.00 % Associated Bank, N.A. Total capital $ 2,532,563 12.76 % $ 1,588,070 ≥ 8.00 % $ 1,985,088 ≥ 10.00 % Tier 1 capital 2,283,785 11.50 1,191,053 ≥ 6.00 % 1,588,070 ≥ 8.00 % Common equity Tier 1 capital 2,084,589 10.50 893,289 ≥ 4.50 % 1,290,307 ≥ 6.50 % Leverage 2,283,785 8.64 1,057,228 ≥ 4.00 % 1,321,535 ≥ 5.00 % (1) When fully phased-in on January 1, 2019, the Basel III capital rules include a capital conservation buffer of 2.5% that is added on top of each of the minimum risk-based capital ratios noted above. Implementation began on January 1, 2016 at the 0.625% level and will increase each subsequent January 1, until it reaches 2.5% on January 1, 2019. (2) Prompt corrective action provisions are not applicable at the bank holding company level.

Earnings Per Common Share

Earnings Per Common Share	12 Months Ended
	Dec. 31, 2016
Earnings Per Share [Abstract]
Earnings Per Common Share	Earnings Per Common Share See Note 1 for the Corporation’s accounting policy on earnings per common share. Presented below are the calculations for basic and diluted earnings per common share. For the Years Ended December 31, 2016 2015 2014 (In thousands, except per share data) Net income $ 200,274 $ 188,301 $ 190,509 Preferred stock dividends (8,903 ) (7,155 ) (5,002 ) Net income available to common equity $ 191,371 $ 181,146 $ 185,507 Common shareholder dividends (67,100 ) (61,774 ) (58,123 ) Unvested share-based payment awards (755 ) (626 ) (587 ) Undistributed earnings $ 123,516 $ 118,746 $ 126,797 Undistributed earnings allocated to common shareholders 122,205 117,498 125,646 Undistributed earnings allocated to unvested share-based payment awards 1,311 1,248 1,151 Undistributed earnings $ 123,516 $ 118,746 $ 126,797 Basic Distributed earnings to common shareholders $ 67,100 $ 61,774 $ 58,123 Undistributed earnings allocated to common shareholders 122,205 117,498 125,646 Total common shareholders earnings, basic $ 189,305 $ 179,272 $ 183,769 Diluted Distributed earnings to common shareholders $ 67,100 $ 61,774 $ 58,123 Undistributed earnings allocated to common shareholders 122,205 117,498 125,646 Total common shareholders earnings, diluted $ 189,305 $ 179,272 $ 183,769 Weighted average common shares outstanding 148,769 149,350 157,286 Effect of dilutive common stock awards 1,192 1,253 968 Diluted weighted average common shares outstanding 149,961 150,603 158,254 Basic earnings per common share $ 1.27 $ 1.20 $ 1.17 Diluted earnings per common share $ 1.26 $ 1.19 $ 1.16 Options to purchase approximately 1 million , 1 million , and 2 million shares were outstanding at December 31, 2016 , 2015 , and 2014 , respectively, but excluded from the calculation of diluted earnings per common share as the effect would have been anti-dilutive. Warrants to purchase approximately 4 million shares were outstanding at December 31, 2016 , 2015 , and 2014, respectively, but excluded from the calculation of diluted earnings per common shares as the effect would have been anti-dilutive.

Segment Reporting

Segment Reporting	12 Months Ended
	Dec. 31, 2016
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 Note 1 , with certain exceptions. The more significant of these exceptions are described herein. The Corporation allocates net interest income using an internal 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. During 2015, the Corporation adopted an enhanced FTP methodology utilizing, new, more granular deposit information which incorporated the additional dimension of vintage (based on time from when the deposit account was opened) for determining the funds credit on non-maturity deposits. The new deposit information demonstrated that deposit accounts with the Corporation for a longer period of time had a lower attrition rate, warranting a higher crediting rate (based on a longer-term segment of the yield curve) to reflect the long-term value such deposits provide to the Corporation. This new methodology resulted in an additional $30 million in allocated net interest income to the Corporate and Commercial Specialty and Community, Consumer, and Business segments for 2015. Prior periods have not been restated for this enhanced FTP methodology due to the impracticability of estimating the impact of the change for prior periods. 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 Note 1 to assess the overall appropriateness of the allowance for loan losses and the allowance for unfunded commitments. 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 tax rate, with certain segments adjusted for any tax-exempt income or non-deductible expenses, the net tax residual is recorded in Risk Management and Shared Services. 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. During 2016 , certain presentation changes were made and, accordingly, 2015 and 2014 results have been restated and presented on a comparable basis, except as noted above for the enhanced FTP methodology. A description of each business segment is presented below. Corporate and Commercial Specialty — The Corporate and Commercial Specialty segment serves a wide range of customers including larger businesses, developers, not-for-profits, municipalities, and financial institutions. In serving this segment we compete based on an in-depth understanding of our customers’ financial needs, the ability to match market competitive solutions to those needs, and the highest standards of relationship and service excellence in the delivery of these services. Delivery of services is provided through our corporate and commercial units, our commercial real estate unit, as well as our specialized industries and commercial financial services units. Within this segment we provide the following products and services: (1) lending solutions, such as commercial loans and lines of credit, commercial real estate financing, construction loans, letters of credit, leasing, asset based lending, and, for our larger clients, loan syndications; (2) deposit and cash management solutions such as commercial checking and interest-bearing deposit products, cash vault and night depository services, liquidity solutions, payables and receivables solutions, and information services, and (3) specialized financial services such as interest rate risk management, foreign exchange solutions, and commodity hedging. Community, Consumer, and Business — The Community, Consumer, and Business segment serves individuals, as well as small and mid-sized businesses. In serving this segment we compete based on providing a broad range of solutions to meet the needs of our customers in their entire financial lifecycle, convenient access to our services through multiple channels such as branches, phone based services, online and mobile banking, and a relationship based business model which assists our customers in navigating any changes and challenges in their financial circumstances. Delivery of services is provided through our various consumer banking, community banking, and private client units. Within this segment we provide the following products and services: (1) lending solutions such as residential mortgages, home equity loans and lines of credit, personal and installment loans, real estate financing, business loans, and business lines of credit; (2) deposit and transactional solutions such as checking, credit, debit and pre-paid cards, online banking and bill pay, and money transfer services; (3) investable funds solutions such as savings, money market deposit accounts, IRA accounts, certificates of deposit, fixed and variable annuities, full-service, discount and on-line investment brokerage; investment advisory services; trust and investment management accounts; (4) insurance and benefits related products and services; and (5) fiduciary services such as administration of pension, profit-sharing and other employee benefit plans, fiduciary and corporate agency services, and institutional asset management. Risk Management and Shared Services — The Risk Management and Shared Services segment includes Corporate Risk Management, Credit Administration, Finance, Treasury, Operations and Technology, which are key shared functions. The segment also includes Parent Company activity, intersegment eliminations and 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). The earning assets within this segment include the Corporation’s investment portfolio, and capital includes both allocated and any remaining unallocated capital. Information about the Corporation’s segments is presented below. Segment Income Statement Data Corporate and Commercial Specialty Community, Consumer, and Business Risk Management and Shared Services Consolidated Total For the Years Ended December 31, ($ in Thousands) 2016 Net interest income $ 328,603 $ 350,551 $ 28,119 $ 707,273 Noninterest income 47,776 277,942 27,165 352,883 Total revenue 376,379 628,493 55,284 1,060,156 Credit provision* 50,397 24,185 (4,582 ) 70,000 Noninterest expense 148,493 502,285 51,782 702,560 Income before income taxes 177,489 102,023 8,084 287,596 Income tax expense (benefit) 59,261 35,708 (7,647 ) 87,322 Net income $ 118,228 $ 66,315 $ 15,731 $ 200,274 Return on average allocated capital (ROCET1)** 11.0 % 10.5 % 2.8 % 9.9 % 2015 Net interest income $ 310,072 $ 349,134 $ 17,072 $ 676,278 Noninterest income 46,742 265,503 17,112 329,357 Total revenue 356,814 614,637 34,184 1,005,635 Credit provision* 41,913 25,614 (30,027 ) 37,500 Noninterest expense 141,912 492,284 64,151 698,347 Income before income taxes 172,989 96,739 60 269,788 Income tax expense (benefit) 59,200 33,859 (11,572 ) 81,487 Net income $ 113,789 $ 62,880 $ 11,632 $ 188,301 Return on average allocated capital (ROCET1)** 11.6 % 9.8 % 2.1 % 9.9 % 2014 Net interest income $ 296,717 $ 310,444 $ 73,806 $ 680,967 Noninterest income 49,213 221,430 20,218 290,861 Total revenue 345,930 531,874 94,024 971,828 Credit provision* 46,857 23,934 (54,791 ) 16,000 Noninterest expense 148,476 463,235 68,072 679,783 Income before income taxes 150,597 44,705 80,743 276,045 Income tax expense 50,039 15,647 19,850 85,536 Net income $ 100,558 $ 29,058 $ 60,893 $ 190,509 Return on average allocated capital (ROCET1)** 11.1 % 5.1 % 13.9 % 9.9 % Segment Balance Sheet Data Corporate and Commercial Specialty Community, Consumer, and Business Risk Management and Shared Services Consolidated Total Average Balance for: ($ in Thousands) 2016 Average earning assets $ 10,178,813 $ 9,309,028 $ 6,538,820 $ 26,026,661 Average loans 10,169,300 9,307,723 173,644 19,650,667 Average deposits 5,904,238 11,451,759 3,649,775 21,005,772 Average allocated capital (CET1)** $ 1,070,598 $ 629,540 $ 240,253 $ 1,940,391 2015 Average earning assets $ 9,383,971 $ 8,810,015 $ 6,377,101 $ 24,571,087 Average loans 9,374,191 8,809,673 68,400 18,252,264 Average deposits 5,856,530 10,898,602 3,147,955 19,903,087 Average allocated capital (CET1)** $ 977,406 $ 640,181 $ 216,010 $ 1,833,597 2014 Average earning assets $ 8,927,401 $ 7,840,352 $ 5,992,375 $ 22,760,128 Average loans 8,915,498 7,840,352 83,144 16,838,994 Average deposits 5,148,195 10,061,495 2,437,394 17,647,084 Average allocated capital (CET1)** $ 903,500 $ 564,303 $ 402,806 $ 1,870,609 * The consolidated credit provision is equal to the actual reported provision for credit losses. ** The Federal Reserve establishes capital adequacy requirements for the Corporation. Average allocated capital represents average common equity Tier 1, as defined by the Federal Reserve. For segment reporting purposes, the ROCET1, a non-GAAP financial measure, reflects return on average allocated common equity Tier 1 (“CET1”). 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)	12 Months Ended
	Dec. 31, 2016
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 of accumulated other comprehensive income (loss) at December 31, 2016 , 2015 , and 2014 , changes during the years then ended, and reclassifications out of accumulated other comprehensive income (loss) during the years ended December 31, 2016 , 2015 , and 2014 , respectively. Investments Securities Available For Sale Defined Benefit Pension and Postretirement Obligations Accumulated Other Comprehensive Income (Loss) ($ in Thousands) Balance December 31, 2013 $ (11,396 ) $ (12,848 ) $ (24,244 ) Other comprehensive income (loss) before reclassifications 49,038 (18,428 ) 30,610 Amounts reclassified from accumulated other comprehensive income (loss): Investment securities gain, net (494 ) — (494 ) Personnel expense — 1,407 1,407 Income tax (expense) benefit (18,636 ) 6,507 (12,129 ) Net other comprehensive income (loss) during period 29,908 (10,514 ) 19,394 Balance December 31, 2014 $ 18,512 $ (23,362 ) $ (4,850 ) Other comprehensive loss before reclassifications (20,439 ) (17,892 ) (38,331 ) Amounts reclassified from accumulated other comprehensive income (loss): Investment securities gain, net (8,133 ) — (8,133 ) Personnel expense — 2,306 2,306 Interest income (555 ) — (555 ) Income tax benefit 11,074 5,873 16,947 Net other comprehensive loss during period (18,053 ) (9,713 ) (27,766 ) Balance December 31, 2015 $ 459 $ (33,075 ) $ (32,616 ) Other comprehensive loss before reclassifications (17,900 ) (6,141 ) (24,041 ) Amounts reclassified from accumulated other comprehensive loss: Investment securities gain, net (9,316 ) — (9,316 ) Personnel expense — 3,801 3,801 Interest income (5,887 ) — (5,887 ) Income tax benefit 12,565 815 13,380 Net other comprehensive loss during period (20,538 ) (1,525 ) (22,063 ) Balance December 31, 2016 $ (20,079 ) $ (34,600 ) $ (54,679 )

Summary of Significant Accoun31

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2016
Accounting Policies [Abstract]
Business and Basis of Financial Statement Presentation	Business 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”) is a bank holding company headquartered in Wisconsin. The Corporation provides a full range of banking and related financial services to consumer and commercial customers through its network of bank and nonbank subsidiaries. The Corporation is subject to competition from other financial and non-financial institutions that offer similar or competing products and services. The Corporation is regulated by federal and state agencies and is subject to periodic examinations by those agencies. Basis of Financial Statement Presentation The consolidated financial statements include the accounts of the Parent Company and its wholly-owned subsidiaries. Investments in unconsolidated entities (none of which are considered to be variable interest entities in which the Corporation is the primary beneficiary) are accounted for using the cost method of accounting when the Corporation has determined that the cost method is appropriate. Investments not meeting the criteria for cost method accounting are accounted for using the equity method of accounting. Investments in unconsolidated entities are included in other assets, and the Corporation’s share of income or loss is recorded in other noninterest income, while distributions in excess of the investment are recorded in gain on assets. All significant intercompany balances and transactions have been eliminated in consolidation.
Use of Estimates	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.
Reclassification, Policy	During 2016, the Corporation modified the consolidated statements of income from prior periods’ presentation to conform with the current period presentation. Specifically, OREO gains / losses were reclassified from Asset gains (losses), net to Foreclosure / OREO expense, net; loan syndications were reclassified from Card-based and other nondeposit fees to Capital market fees, net; and bond underwriting was reclassified from Other noninterest income to Capital market fees, net. In addition, the Corporation combined the lease financing portfolio with the commercial and industrial portfolio for disclosure purposes. All prior periods have been reclassified to reflect these immaterial reclassifications. During the first quarter of 2016, the Corporation adopted a new accounting standard related to simplifying the presentation of debt issuance costs. Under this new accounting standard, debt issuance costs are still capitalized; however, they are reflected on the balance sheet with the related debt issued rather than within other assets. All prior period balance sheets were required to be restated to reflect this change in presentation.
Investment Securities	Investment Securities Securities are classified as held to maturity or available for sale at the time of purchase. Investment securities classified as held to maturity, which management has the positive intent and ability to hold to maturity, are reported at amortized cost. Investment securities classified as available for sale, which management has the intent and ability to hold for an indefinite period of time, but not necessarily to maturity, are carried at fair value, with unrealized gains and losses, net of related deferred income taxes, included in stockholders’ equity as a separate component of other comprehensive income. Any decision to sell investment securities available for sale would be based on various factors, including, but not limited to, asset / liability management strategies, changes in interest rates or prepayment risks, liquidity needs, or regulatory capital considerations. Realized gains or losses on investment security sales (using specific identification method) are included in investment securities gains (losses), net, in the consolidated statements of income. Premiums and discounts are amortized or accreted into interest income over the estimated life (earlier of call date, maturity, or estimated life) of the related security, using a prospective method that approximates level yield. In certain situations, management may elect to transfer certain investment securities from the available for sale classification to the held to maturity classification. In such cases, the investment securities are reclassified at fair value at the time of transfer. Any unrealized gain or loss included in accumulated other comprehensive income (loss) at the time of transfer is retained therein and amortized over the remaining life of the investment security as an adjustment to yield. Declines in the fair value of investment securities (with certain exceptions for debt securities noted below) that are deemed to be other-than-temporary are charged to earnings as a realized loss, and a new cost basis for the investment security is established. In evaluating other-than-temporary impairment, management considers the length of time and extent to which the security has been in an unrealized loss position, changes in security ratings, the financial condition and near-term prospects of the issuer, as well as security and industry specific economic conditions. In addition, the Corporation considers the intent and ability to retain its investment in the issuer for a period of time sufficient to allow for any anticipated recovery in fair value in the near term. Declines in the fair value of debt securities below amortized cost are deemed to be other-than-temporary in circumstances where: (1) the Corporation has the intent to sell a security; (2) it is more likely than not that the Corporation will be required to sell the security before recovery of its amortized cost basis; or (3) the Corporation does not expect to recover the entire amortized cost basis of the security. If the Corporation intends to sell a security or if it is more likely than not that the Corporation will be required to sell the security before recovery, an other-than-temporary impairment write-down is recognized in earnings equal to the difference between the security’s amortized cost basis and its fair value. If an entity does not intend to sell the security or it is more likely than not that it will not be required to sell the security before recovery, the other-than-temporary impairment write-down is separated into an amount representing credit loss, which is recognized in earnings, and an amount related to all other factors, which is recognized in other comprehensive income. Declines in value determined to be other-than-temporary are included in investment securities gains (losses), net, in the consolidated statements of income. See Note 3 for additional information on investment securities.
Federal Home Loan Bank (FHLB) and Federal Reserve Bank Stocks	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. See Note 3 for additional information on the FHLB and Federal Reserve Bank Stocks.
Loans Held for Sale	Loans Held for Sale Loans held for sale, which consist generally of current production of certain fixed-rate, first-lien residential mortgage loans, are carried at the lower of cost or estimated fair value as determined on an aggregate basis. The amount by which cost exceeds estimated fair value is accounted for as a market valuation adjustment to the carrying value of the loans. Changes, if any, in the market valuation adjustment are included in mortgage banking, net, in the consolidated statements of income.
Loans	Loans Loans that management has the intent and ability to hold for the foreseeable future or until maturity or pay-off are reported at their outstanding principal balances, net of any deferred fees and costs on originated loans. Origination fee income received on loans and amounts representing the estimated direct costs of origination are deferred and amortized to interest income over the life of the loan using the effective interest method. An allowance for loan losses is established for estimated credit losses in the loan portfolio. See Allowance for Loan Losses below for further policy discussion. Nonaccrual Loans : 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. This determination is based on management's review of current information and other events regarding the borrowers’ ability to repay their obligations. 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. Interest income on loans is based on the principal balance outstanding computed using the effective interest method. The accrual of interest income for commercial loans is discontinued when there is a clear indication that the borrower’s cash flow may not be sufficient to meet payments as they become due, while the accrual of interest income for consumer loans is discontinued when loans reach specific delinquency levels. Loans are considered past due if the required principal and interest payments have not been received as of the date such payments were due. Loans are generally placed on nonaccrual status when contractually past due 90 days or more as to interest or principal payments, unless the loan is well secured and in the process of collection. Additionally, whenever management becomes aware of facts or circumstances that may adversely impact the collectability of principal or interest on loans, it is management’s practice to place such loans on a nonaccrual status immediately, rather than delaying such action until the loans become 90 days past due. When a loan is placed on nonaccrual status, previously accrued and uncollected interest is reversed, amortization of related deferred loan fees or costs is suspended, and income is recorded only to the extent that interest payments are subsequently received in cash and a determination has been made that the principal and interest of the loan is collectible. If collectability of the principal and interest is in doubt, payments received are applied to loan principal. While a loan is in nonaccrual status, some or all of the cash interest payments received may be treated as interest income on a cash basis as long as the remaining recorded investment in the loan (i.e., after charge off of identified losses, if any) is deemed to be fully collectible. The determination as to the ultimate collectability of the loan's remaining recorded investment must be supported by a current, well documented credit evaluation of the borrower’s financial condition and prospects for repayment, including consideration of the borrower’s sustained historical repayment performance and other relevant factors. A nonaccrual loan is returned to accrual status when all delinquent principal and interest payments become current in accordance with the terms of the loan agreement, the borrower has demonstrated a period of sustained repayment performance, and the ultimate collectability of the total contractual principal and interest is no longer in doubt. A sustained period of repayment performance generally would be a minimum of six months. See Note 4 for additional information on loans.
Troubled Debt Restructurings (Restructured Loans)	Troubled Debt Restructurings (“Restructured Loans”) : Loans are considered restructured loans if concessions have been granted to borrowers that are experiencing financial difficulty. The concessions granted generally involve the modification of terms of the loan, such as changes in payment schedule or interest rate, which generally would not otherwise be considered. Restructured loans can involve loans remaining on nonaccrual, moving to nonaccrual, or continuing on accrual status, depending on the individual facts and circumstances of the borrower. Nonaccrual restructured loans are included and treated with all other nonaccrual loans. In addition, all accruing restructured loans are reported as troubled debt restructurings, which are considered and accounted for as impaired loans. Generally, restructured loans remain on nonaccrual until the customer has attained a sustained period of repayment performance under the modified loan terms (generally a minimum of six months). However, performance prior to the restructuring, or significant events that coincide with the restructuring, are considered in assessing whether the borrower can meet the new terms and whether the loan should be returned to or maintained on accrual status. If the borrower’s ability to meet the revised payment schedule is not reasonably assured, the loan remains on nonaccrual status. See Note 4 for additional information on restructured loans.
Allowance for Loan Losses	Allowance for Loan Losses : The allowance for loan losses is a reserve for estimated credit losses on individually evaluated loans determined to be impaired as well as estimated credit losses inherent in the loan portfolio, and is based on quarterly evaluations of the collectability and historical loss experience of loans. Actual credit losses, net of recoveries, are deducted from the allowance for loan losses. A provision for loan losses, which is a charge against earnings, is recorded to bring the allowance for loan losses to a level that, in management’s judgment, is appropriate to absorb probable losses in the loan portfolio. The methodology applied by the Corporation, designed to assess the appropriateness of the allowance for loan losses, is based upon management’s ongoing review and grading of the loan portfolio into criticized loan categories (defined as specific loans warranting either specific allocation, or a criticized status of special mention, substandard, doubtful, or loss). The methodology also focuses on evaluation of several factors, including but not limited to: evaluation of facts and issues related to specific loans, management’s ongoing review and grading of the loan portfolio, consideration of historical loan loss and delinquency experience on each portfolio category, trends in past due and nonaccrual loans, the level of potential problem loans, the risk characteristics of the various classifications of loans, changes in the size and character of the loan portfolio, concentrations of loans to specific borrowers or industries, existing economic conditions, the fair value of underlying collateral, and other qualitative and quantitative factors which could affect potential credit losses. Because each of the criteria used is subject to change, the analysis of the allowance for loan losses is not necessarily indicative of the trend of future loan losses in any particular loan category. The total allowance for loan losses is available to absorb losses from any segment of the loan portfolio. When an individual loan is determined to be impaired, the allowance for loan losses attributable to the loan is allocated based on management’s estimate of the borrower’s ability to repay the loan given the availability of collateral, other sources of cash flows, as well as evaluation of legal options available to the Corporation. The amount of impairment is measured based upon the present value of expected future cash flows discounted at the loan’s effective interest rate, the fair value of the underlying collateral less applicable selling costs, or the observable market price of the loan. If foreclosure is probable or the loan is collateral dependent, impairment is measured using the fair value of the loan’s collateral, less costs to sell. Large groups of homogeneous loans, such as residential mortgage, home equity, and other consumer, are collectively evaluated for impairment. Management believes that the level of the allowance for loan losses is appropriate. While management uses currently available information to recognize losses on loans, future adjustments to the allowance for loan losses may be necessary based on newly received appraisals, updated commercial customer financial statements, rapidly deteriorating cash flow, and changes in economic conditions that affect our customers. In addition, various regulatory agencies, as an integral part of their examination process, periodically review the Corporation’s allowance for loan losses. Such agencies may require additions to the allowance for loan losses or may require that certain loan balances be charged off or downgraded into criticized loan categories when their credit evaluations differ from those of management based on their judgments about information available to them at the time of their examinations. See Loans and Troubled Debt Restructurings above for further policy discussion and see Note 4 for additional information on the allowance for loan losses.
Other Real Estate Owned	Other Real Estate Owned Other real estate owned is included in other assets in the consolidated balance sheets and is comprised of property acquired through a foreclosure proceeding or acceptance of a deed-in-lieu of foreclosure, and loans classified as in-substance foreclosure. Other real estate owned is recorded at the fair value of the underlying property collateral, less estimated selling costs. This fair value becomes the new cost basis for the foreclosed asset. The initial write-down, if any, will be recorded as a charge off against the allowance for loan losses. Any subsequent write-downs to reflect current fair value, as well as gains and losses on disposition and revenues and expenses incurred in maintaining such properties, are expensed as incurred. Other real estate owned also includes bank premises formerly but no longer used for banking as well as property originally acquired for future expansion but no longer intended to be used for that purpose. Banking premises are transferred at the lower of carrying value or fair value, less estimated selling costs and any write-down is expensed as incurred.
Reserve for Unfunded Commitments	Allowance for Unfunded Commitments 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 in the consolidated balance sheets. The determination of the appropriate level of the allowance for unfunded commitments is based upon an evaluation of the unfunded credit facilities, including an assessment of historical commitment utilization experience and credit risk grading of the loan. Net adjustments to the allowance for unfunded commitments are included in the provision for credit losses in the consolidated statements of income. See Note 4 and Note 16 for additional information on the allowance for unfunded commitments.
Mortgage Repurchase Reserve	Mortgage Repurchase Reserve The Corporation sells residential mortgage loans to investors in the normal course of business. Residential mortgage loans sold to investors are predominantly conventional residential first lien mortgages originated under the usual underwriting procedures, and are most often sold on a nonrecourse basis, primarily to the Government Sponsored Enterprises ("GSE"). The Corporation’s agreements to sell residential mortgage loans usually require certain representations and warranties on the underlying loans sold, related to credit information, loan documentation, collateral, and insurability, which if subsequently untrue or breached, could require the Corporation to indemnify or repurchase certain loans affected. To a much lesser degree, the Corporation may 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 indemnification or repurchase could be required if the loan had defined delinquency issues during the limited recourse periods. The balance in the repurchase reserve at the balance sheet date reflects the estimated amount of potential loss the Corporation could incur from repurchasing a loan (“put back” requests), as well as loss reimbursements, indemnification, and other settlement resolutions (“make whole” payments). See Note 16 for additional information on the mortgage repurchase reserve.
Premises and Equipment and Software	Premises and Equipment and Software Premises and equipment are stated at cost less accumulated depreciation and amortization. Depreciation and amortization are computed on the straight-line method over the estimated useful lives of the related assets or the lease term. Maintenance and repairs are charged to expense as incurred, while additions or major improvements are capitalized and depreciated over the estimated useful lives. Leasehold improvements are amortized on a straight-line basis over the lesser of the lease terms or the estimated useful lives of the improvements. Software, included in other assets in the consolidated balance sheets, is amortized on a straight-line basis over the lesser of the contract terms or the estimated useful life of the software. See Note 6 for additional information on premises and equipment.
Goodwill and Intangible Assets	Goodwill and Intangible Assets Goodwill and Other Intangible Assets : The excess of the cost of an acquisition over the fair value of the net assets acquired consists primarily of goodwill, core deposit intangibles, and other identifiable intangibles (primarily related to customer relationships acquired). Core deposit intangibles have estimated finite lives and are amortized on an accelerated basis to expense over a 10 -year period. The other intangibles have estimated finite lives and are amortized on an accelerated basis to expense over their weighted average life (a weighted average life of 12 years for both 2016 and 2015 ). The Corporation reviews long-lived assets and certain identifiable intangibles for impairment at least annually, or whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable, in which case an impairment charge would be recorded. 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 impairment testing process is conducted by assigning net assets and goodwill to each reporting unit. An initial qualitative evaluation is made to assess the likelihood of impairment and determine whether further quantitative testing to calculate the fair value is necessary. When the qualitative evaluation indicates that impairment is more likely than not, quantitative testing is required whereby the fair value of each reporting unit is calculated and compared to the recorded book value, “step one.” If the calculated fair value of the reporting unit exceeds its carrying value, goodwill is not considered impaired and “step two” is not considered necessary. If the carrying value of a reporting unit exceeds its calculated fair value, the impairment test continues (“step two”) by comparing the carrying value of the reporting unit’s goodwill to the implied fair value of goodwill. The implied fair value is computed by adjusting all assets and liabilities of the reporting unit to current fair value with the offset adjustment to goodwill. The adjusted goodwill balance is the implied fair value of the goodwill. An impairment charge is recognized if the carrying value of goodwill exceeds the implied fair value of goodwill. See Note 5 for additional information on goodwill and other intangible assets. Mortgage Servicing Rights : The Corporation sells residential mortgage loans in the secondary market and typically retains the right to service the loans sold. Upon sale, a mortgage servicing rights asset is capitalized, which represents the then current fair value of future net cash flows expected to be realized for performing servicing activities. Mortgage servicing rights, when purchased, are initially recorded at fair value. As the Corporation has not elected to subsequently measure any class of servicing assets under the fair value measurement method, the Corporation follows the amortization method. 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. Mortgage servicing rights are carried at the lower of the initial capitalized amount, net of accumulated amortization, or estimated fair value, in the consolidated balance sheets. The Corporation periodically 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 5 for additional information on mortgage servicing rights.
Income Taxes	Income Taxes Amounts provided for income tax expense are based on income reported for financial statement purposes and do not necessarily represent amounts currently payable under tax laws. Deferred income taxes, which arise principally from temporary differences between the amounts reported in the financial statements and the tax bases of assets and liabilities, are included in the amounts provided for income taxes. In assessing the realizability of deferred tax assets, management considers whether it is more likely than not that some portion or all of the deferred tax assets will not be realized. The ultimate realization of deferred tax assets is dependent upon the generation of future taxable income and tax planning strategies which will create taxable income during the periods in which those temporary differences become deductible. Management considers the scheduled reversal of deferred tax liabilities, the amount of taxes paid in available carryback years, projected future taxable income, and, if necessary, tax planning strategies in making this assessment. The Corporation files a consolidated federal income tax return and separate or combined state income tax returns. Accordingly, amounts equal to tax benefits of those subsidiaries having taxable federal or state losses or credits are offset by other subsidiaries that incur federal or state tax liabilities. It is the Corporation’s policy to provide for uncertainty in income taxes as a part of income tax expense based upon management’s assessment of whether a tax benefit is more likely than not to be sustained upon examination by tax authorities. At December 31, 2016 and 2015 , the Corporation believes it has appropriately accounted for any unrecognized tax benefits. To the extent the Corporation prevails in matters for which a liability for an unrecognized tax benefit was established or is required to pay amounts in excess of the liability established, the Corporation’s effective tax rate in a given financial statement period may be effected. See Note 13 for additional information on income taxes.
Derivative and Hedging Activities	Derivative and Hedging Activities Derivative instruments, including derivative instruments embedded in other contracts, are carried at fair value on the consolidated balance sheets with changes in the fair value recorded to earnings or accumulated other comprehensive income, as appropriate. On the date the derivative contract is entered into, the Corporation designates the derivative as a fair value hedge (i.e., a hedge of the fair value of a recognized asset or liability), a cash flow hedge (i.e., a hedge of the variability of cash flows to be received or paid related to a recognized asset or liability), or a free-standing derivative instrument. For a derivative designated as a fair value hedge, the changes in the fair value of the derivative instrument and the changes in the fair value of the hedged asset or liability are recognized in current period earnings as an increase or decrease to the carrying value of the hedged item on the balance sheet and in the related income statement account. For a derivative designated as a cash flow hedge, the effective portions of changes in the fair value of the derivative instrument are recorded in other comprehensive income and the ineffective portions of changes in the fair value of a derivative instrument are recognized in current period earnings as an adjustment to the related income statement account. Amounts within accumulated other comprehensive income are reclassified into earnings in the period the hedged item affects earnings. For a derivative is designated as a free-standing derivative instrument, changes in fair value are reported in current period earnings. At December 31, 2016 and 2015 , the Corporation only had free-standing derivative instruments to facilitate customer borrowing activity. These free-standing derivative instruments included: interest rate risk management, commodity hedging, and foreign currency exchange solutions. See Note 14 for additional information on derivative and hedging activities.
Retirement Plan	Retirement Plans The funded status of the retirement plans are recognized as an asset or liability in the consolidated balance sheets, and changes in that funded status are recognized in the year in which the changes occur through other comprehensive income. Plan assets and benefit obligations are measured as of fiscal year end. The measurement of the projected benefit obligation and pension expense involve actuarial valuation methods and the use of various actuarial and economic assumptions. The Corporation monitors the assumptions and updates them periodically. Due to the long-term nature of the pension plan obligation, actual results may differ significantly from estimations. Such differences are adjusted over time as the assumptions are replaced by facts and values are recalculated. See Note 12 for additional information on the Corporation’s retirement plans.
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 common 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. 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. See Note 11 for additional information on stock-based compensation.
Comprehensive Income	Comprehensive Income Comprehensive income includes all changes in stockholders’ equity during a period, except those resulting from transactions with stockholders. In addition to net income, other components of the Corporation’s comprehensive income include the after tax effect of changes in net unrealized gain / loss on securities available for sale and changes in net actuarial gain / loss on defined benefit postretirement plans. Comprehensive income is reported in the accompanying consolidated statements of changes in stockholder’s equity and consolidated statements of comprehensive income. See Note 22 for additional information on accumulated other comprehensive income (loss).
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). As there is no active market for many of the Corporation’s financial instruments, estimates are made using discounted cash flow or other valuation techniques. Inputs into the valuation methods are subjective in nature, involve uncertainties, and require significant judgment and therefore cannot be determined with precision. Accordingly, the derived fair value estimates presented herein are not necessarily indicative of the amounts the Corporation could realize in a current market exchange. Assets and liabilities are categorized into three levels based on the markets in which the assets and liabilities are traded and the reliability of the assumptions used to determine fair value. In instances where the determination of the fair value measurement is based on inputs from different levels of the fair value hierarchy, the level in the fair value hierarchy in which the entire fair value measurement falls is based on the lowest level input that is significant to the fair value measurement in its entirety. The Corporation’s assessment of the significance of a particular input to the fair value measurement in its entirety requires judgment, and considers factors specific to the asset or liability. See Note 18 for additional information on fair value measurements. Below is a brief description of each fair value level. Level 1 — Level 1 inputs utilize quoted prices (unadjusted) in active markets for identical assets or liabilities that the Corporation has the ability to access. Level 2 — Level 2 inputs are inputs other than quoted prices included in Level 1 that are observable for the asset or liability, either directly or indirectly. Level 2 inputs may include quoted prices for similar assets and liabilities in active markets, as well as inputs that are observable for the asset or liability (other than quoted prices), such as interest rates, foreign exchange rates, and yield curves that are observable at commonly quoted intervals. Level 3 — Level 3 inputs are unobservable inputs for the asset or liability, which are typically based on an entity’s own assumptions, as there is little, if any, related market activity.
Cash and Cash Equivalents	Cash and Cash Equivalents For purposes of the consolidated statements of cash flows, cash and cash equivalents are considered to include cash and due from banks, interest-bearing deposits in other financial institutions, and federal funds sold and securities purchased under agreements to resell.
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, unvested restricted stock awards, and outstanding common stock warrants). See Note 20 for additional information on earnings per common share.
New Accounting Pronouncements Adopted	New Accounting Pronouncements Adopted In December 2016, the FASB issued a technical corrections and improvements accounting standards update which makes minor amendments to the FASB Accounting Standards Codification. The four general topics covered in the guidance include: (1) amendments related to differences between original guidance and the codification, (2) guidance clarification and reference corrections, (3) simplification, and (4) minor improvements. The amendments that require transition guidance are effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2016. The amendments that require transition guidance are not applicable to the Corporation. All other amendments were effective upon the issuance of this update in December 2016. The Corporation adopted the accounting standard during the fourth quarter of 2016, as required, with no material impact on its results of operations, financial position, or liquidity. In March 2016, 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. This amendment is effective for annual periods, and interim periods within those annual periods, beginning after December 15, 2016. 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. An entity may elect to apply the amendments related to the presentation of excess tax benefits on the statement of cash flows using either a prospective transition method or a retrospective transition method. The Corporation early adopted the accounting standard during the fourth quarter of 2016 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. In September 2015, the FASB issued an amendment to simplify the accounting for measurement adjustments to prior business combinations. The amendment requires that an acquirer recognize adjustments to provisional amounts that are identified during the measurement period in the reporting period in which the adjustment amounts are determined. The acquirer must record, in the same period’s financial statements, the effect on earnings of changes in depreciation, amortization, or other income effects, if any, as a result of the change to the provisional amounts, calculated as if the accounting had been completed at the acquisition date. The amendment also requires an entity to present separately on the face of the income statement or disclose in the notes the portion of the amount recorded in current-period earnings by line item that would have been recorded in previous reporting periods if the adjustment to the provisional amounts had been recognized as of the acquisition date. This amendment was effective for fiscal years beginning after December 15, 2015, including interim periods within those fiscal years. The Corporation adopted the accounting standard during the first quarter of 2016, as required, with no material impact on its results of operations, financial position, or liquidity. In May 2015, the FASB issued an amendment to eliminate the requirement to categorize investments measured using the net asset value per share ("NAV") practical expedient in the fair value hierarchy table. Entities are required to disclose the fair value of investments measured using the NAV practical expedient so that financial statement users can reconcile amounts reported in the fair value hierarchy table to amounts reported on the balance sheet. This amendment required retrospective application and was effective for fiscal years beginning after December 15, 2015, and interim periods within those fiscal years. The Corporation adopted the accounting standard during the first quarter of 2016, as required, with no material impact on its results of operations, financial position, or liquidity. See Note 12 for additional disclosure regarding reconciliation of the fair value hierarchy to the amounts presented in the balance sheet. In April 2015, the FASB issued an amendment to provide guidance to customers about whether a cloud computing arrangement included a software license. If the cloud computing arrangement includes a software license, then the customer should account for the software license element consistent with the acquisition of other software licenses. If a cloud computing arrangement does not include a software license, the customer should account for the arrangement as a service contract. This amendment was effective for annual periods, and interim periods within those annual periods, beginning after December 15, 2015. The Corporation adopted the accounting standard on a prospective basis during the first quarter of 2016, as required, with no material impact on its results of operations, financial position, or liquidity. In April 2015, the FASB issued an amendment to simplify the presentation of debt issuance costs. This amendment requires that debt issuance costs related to a recognized debt liability be presented in the balance sheet as a direct deduction from the carrying amount of that debt liability, consistent with debt discounts. In August 2015, the FASB expanded this amendment to include SEC staff views related to debt issuance costs associated with line-of-credit arrangements. The SEC staff would not object to an entity deferring and presenting debt issuance costs as an asset and subsequently amortizing the deferred debt issuance costs over the term of the line-of-credit arrangement, regardless of whether there are any outstanding borrowings on the line-of-credit arrangement. This amendment required retrospective application and was effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2015. The Corporation adopted the accounting standard during the first quarter of 2016. All prior periods have been restated to reflect this change in presentation, resulting in a $3 million reduction to other assets and a corresponding $3 million reduction to long-term funding on the balance sheet compared to the amounts originally reported at December 31, 2015. In February 2015, the FASB issued an amendment to modify existing consolidation guidance for reporting companies that are required to evaluate whether they should consolidate legal entities. The new standard will place more emphasis on risk of loss when determining a controlling financial interest. Frequency in the application of related-party guidance for determining a controlling financial interest will be reduced. Also, consolidation conclusions for public and private companies among several industries that make use of limited partnerships or VIEs changed. This amendment was effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2015. The Corporation adopted the accounting standard during the first quarter of 2016, as required, with no material impact on its results of operations, financial position, or liquidity. In January 2015, the FASB issued an amendment to eliminate from U.S. GAAP the concept of extraordinary items. Presently, an event or transaction is presumed to be an ordinary and usual activity of the reporting entity unless evidence clearly supports its classification as an extraordinary item. If an event or transaction meets the criteria for extraordinary classification, an entity is required to segregate the extraordinary item from the results of ordinary operations and show the item separately in the income statement, net of tax, after income from continuing operations. The amended guidance prohibits separate disclosure of extraordinary items in the income statement. This amendment was effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2015. The Corporation adopted the accounting standard during the first quarter of 2016, as required, with no material impact. In June 2014, the FASB issued an amendment to the stock compensation accounting guidance to clarify that a performance target that affects vesting of a share-based payment and that could be achieved after the requisite service period be treated as a performance condition. As such, the performance target should not be reflected in estimating the grant-date fair value of the award. Compensation cost should be recognized in the period in which it becomes probable that the performance target will be achieved and should represent the compensation cost attributable to the period(s) for which the requisite service has already been rendered. This amendment was effective for annual reporting periods, including interim periods within those annual periods, beginning after December 15, 2015. The Corporation adopted the accounting standard on a prospective basis during the first quarter of 2016, as required, with no material impact on its results of operations, financial position, or liquidity.

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2016
Fair Value Disclosures [Abstract]
Assets and liabilities measured on recurring basis at fair value	The table below presents the Corporation’s investment securities available for sale and derivative financial instruments measured at fair value on a recurring basis as of December 31, 2016 and 2015 , aggregated by the level in the fair value hierarchy within which those measurements fall. Assets and Liabilities Measured at Fair Value on a Recurring Basis Fair Value Hierarchy December 31, 2016 December 31, 2015 ($ in Thousands) Assets: Investment securities available for sale: U.S. Treasury securities Level 1 $ 1,000 $ 997 Residential mortgage-related securities: FNMA / FHLMC Level 2 639,930 1,414,626 GNMA Level 2 2,004,475 1,590,003 Private-label Level 2 1,121 1,709 GNMA commercial mortgage-related securities Level 2 2,028,898 1,955,310 Other securities (debt and equity) Level 1 1,602 1,569 Other securities (debt and equity) Level 2 3,000 3,000 Other securities (debt and equity) Level 3 200 200 Total investment securities available for sale Level 1 2,602 2,566 Total investment securities available for sale Level 2 4,677,424 4,964,648 Total investment securities available for sale Level 3 200 200 Interest rate-related instruments Level 2 33,671 29,391 Foreign currency exchange forwards Level 2 2,002 1,532 Interest rate lock commitments to originate residential mortgage loans held for sale Level 3 206 958 Forward commitments to sell residential mortgage loans Level 3 2,908 403 Commodity contracts Level 2 16,725 1,269 Purchased options (time deposit) Level 2 2,576 2,715 Liabilities: Interest rate-related instruments Level 2 $ 33,188 $ 30,886 Foreign currency exchange forwards Level 2 1,943 1,398 Commodity contracts Level 2 15,972 1,146 Written options (time deposit) Level 2 2,576 2,715
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 years ended December 31, 2016 and 2015 , 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, 2014 $ 200 $ (488 ) Total net gains included in income: Mortgage derivative gain — 1,849 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
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. Assets and Liabilities Measured at Fair Value on a Nonrecurring Basis Income Statement Category of Adjustment Recognized in Income Fair Value Hierarchy Fair Value ($ in Thousands) December 31, 2016 Assets: Commercial loans held for sale Level 2 $ 12,474 Provision for credit losses $ (559 ) Mortgage loans held for sale Level 2 108,010 Mortgage banking, net (3,760 ) Impaired loans (1) Level 3 79,270 Provision for credit losses (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 December 31, 2015 Assets: Mortgage loans held for sale Level 2 $ 124,915 Mortgage banking, net $ (155 ) Impaired loans (1) Level 3 41,891 Provision for credit losses (7,796 ) Other real estate owned Level 2 10,988 Foreclosure / OREO expense, net (2,653 ) Mortgage servicing rights Level 3 70,686 Mortgage banking, net 425 (1) Represents individually evaluated impaired loans, net of the related allowance for loan losses.
Estimated fair values of financial instruments	Fair value estimates, methods, and assumptions are set forth below for the Corporation’s financial instruments. December 31, 2016 December 31, 2015 Fair Value Hierarchy Level Carrying Amount Fair Value Carrying Amount Fair Value ($ in Thousands) Financial assets: Cash and due from banks Level 1 $ 446,558 $ 446,558 $ 374,921 $ 374,921 Interest-bearing deposits in other financial institutions Level 1 149,175 149,175 79,764 79,764 Federal funds sold and securities purchased under agreements to resell Level 1 46,500 46,500 19,000 19,000 Investment securities held to maturity Level 2 1,273,536 1,264,674 1,168,230 1,184,442 Investment securities available for sale Level 1 2,602 2,602 2,566 2,566 Investment securities available for sale Level 2 4,677,424 4,677,424 4,964,648 4,964,648 Investment securities available for sale Level 3 200 200 200 200 FHLB and Federal Reserve Bank stocks Level 2 140,001 140,001 147,240 147,240 Loans held for sale Level 2 120,484 120,484 124,915 124,915 Loans, net Level 3 19,776,381 19,680,317 18,440,079 18,389,832 Bank owned life insurance Level 2 585,290 585,290 583,019 583,019 Derivatives (trading and other assets) Level 2 54,974 54,974 34,907 34,907 Derivatives (trading and other assets) Level 3 3,114 3,114 1,361 1,361 Financial liabilities: Noninterest-bearing demand, savings, interest-bearing demand, and money market accounts Level 3 $ 20,282,321 $ 20,282,321 $ 19,444,863 $ 19,444,863 Brokered CDs and other time deposits Level 2 1,606,127 1,606,127 1,562,802 1,564,464 Short-term funding Level 2 1,092,035 1,092,035 834,416 834,416 Long-term funding Level 2 2,761,795 2,791,841 2,676,164 2,728,112 Standby letters of credit (1) Level 2 2,566 2,566 2,954 2,954 Derivatives (trading and other liabilities) Level 2 53,679 53,679 36,145 36,145 (1) The commitment on standby letters of credit was $260 million and $297 million at December 31, 2016 and 2015 , respectively. See Note 16 for additional information on the standby letters of credit and for information on the fair value of lending-related commitments.

Investment Securities (Tables)

Investment Securities (Tables)	12 Months Ended
	Dec. 31, 2016
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. December 31, 2016 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses 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 December 31, 2015 Amortized Gross Gross Fair Value ($ in Thousands) Investment securities available for sale: U. S. Treasury securities $ 999 $ — $ (2 ) $ 997 Residential mortgage-related securities: FNMA / FHLMC 1,388,995 33,791 (8,160 ) 1,414,626 GNMA 1,605,956 507 (16,460 ) 1,590,003 Private-label 1,722 1 (14 ) 1,709 GNMA commercial mortgage-related securities 1,982,477 1,334 (28,501 ) 1,955,310 Other securities (debt and equity) 4,718 51 — 4,769 Total investment securities available for sale $ 4,984,867 $ 35,684 $ (53,137 ) $ 4,967,414 Investment securities held to maturity: Municipal securities $ 1,043,767 $ 16,803 $ (339 ) $ 1,060,231 Residential mortgage-related securities: FNMA / FHLMC 41,469 513 (645 ) 41,337 GNMA 82,994 189 (309 ) 82,874 Total investment securities held to maturity $ 1,168,230 $ 17,505 $ (1,293 ) $ 1,184,442
Investment securities held to maturity	The amortized cost and fair values of securities available for sale and held to maturity were as follows. December 31, 2016 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses 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 December 31, 2015 Amortized Gross Gross Fair Value ($ in Thousands) Investment securities available for sale: U. S. Treasury securities $ 999 $ — $ (2 ) $ 997 Residential mortgage-related securities: FNMA / FHLMC 1,388,995 33,791 (8,160 ) 1,414,626 GNMA 1,605,956 507 (16,460 ) 1,590,003 Private-label 1,722 1 (14 ) 1,709 GNMA commercial mortgage-related securities 1,982,477 1,334 (28,501 ) 1,955,310 Other securities (debt and equity) 4,718 51 — 4,769 Total investment securities available for sale $ 4,984,867 $ 35,684 $ (53,137 ) $ 4,967,414 Investment securities held to maturity: Municipal securities $ 1,043,767 $ 16,803 $ (339 ) $ 1,060,231 Residential mortgage-related securities: FNMA / FHLMC 41,469 513 (645 ) 41,337 GNMA 82,994 189 (309 ) 82,874 Total investment securities held to maturity $ 1,168,230 $ 17,505 $ (1,293 ) $ 1,184,442
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 December 31, 2016 , 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 $ 4,500 $ 4,479 $ 38,791 $ 28,517 Due after one year through five years 1,200 1,200 257,652 264,427 Due after five years through ten years — — 229,063 229,364 Due after ten years — — 620,337 615,367 Total debt securities 5,700 5,679 1,145,843 1,137,675 Residential mortgage-related securities: FNMA / FHLMC 625,234 639,930 37,697 37,443 GNMA 2,028,301 2,004,475 89,996 89,556 Private-label 1,134 1,121 — — GNMA commercial mortgage-related securities 2,064,508 2,028,898 — — Equity securities 18 123 — — Total investment securities $ 4,724,895 $ 4,680,226 $ 1,273,536 $ 1,264,674 Ratio of Fair Value to Amortized Cost 99.1 % 99.3 %
Realized gains and losses and proceeds from sale	Total proceeds and gross realized gains and losses from sales of investment securities for each of the three years ended December 31 were as follows. There were no other-than-temporary impairment write-downs on investment securities for 2016 , 2015 , or 2014 . 2016 2015 2014 ($ in Thousands) Gross gains $ 9,518 $ 12,270 $ 1,184 Gross losses (202 ) (4,137 ) (690 ) Investment securities gains, net $ 9,316 $ 8,133 $ 494 Proceeds from sales of investment securities $ 549,555 $ 1,601,947 $ 102,011
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 December 31, 2016 . Less than 12 months 12 months or more Total Number of Securities Unrealized Losses Fair Value Number of Securities Unrealized Losses Fair Value Unrealized Losses Fair Value ($ in Thousands) 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 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, 2015 . Less than 12 months 12 months or more Total Number Unrealized Fair Number Unrealized Fair Unrealized Fair ($ in Thousands) Investment securities available for sale: U.S. Treasury securities 1 $ (2 ) $ 997 — $ — $ — $ (2 ) $ 997 Residential mortgage-related securities: FNMA / FHLMC 17 (1,548 ) 220,852 14 (6,612 ) 338,186 (8,160 ) 559,038 GNMA 46 (16,460 ) 1,434,484 — — — (16,460 ) 1,434,484 Private-label 1 (1 ) 83 3 (13 ) 1,565 (14 ) 1,648 GNMA commercial mortgage-related securities 40 (9,610 ) 1,132,844 21 (18,891 ) 448,218 (28,501 ) 1,581,062 Total 105 $ (27,621 ) $ 2,789,260 38 $ (25,516 ) $ 787,969 $ (53,137 ) $ 3,577,229 Investment securities held to maturity: Municipal securities 53 $ (146 ) $ 23,137 24 $ (193 ) $ 9,254 $ (339 ) $ 32,391 Residential mortgage-related securities: FNMA / FHLMC 10 (177 ) 12,754 3 (468 ) 11,106 (645 ) 23,860 GNMA 21 (201 ) 45,499 3 (108 ) 6,797 (309 ) 52,296 Total 84 $ (524 ) $ 81,390 30 $ (769 ) $ 27,157 $ (1,293 ) $ 108,547

Loans (Tables)

Loans (Tables)	12 Months Ended
	Dec. 31, 2016
Receivables [Abstract]
Loan composition	Loans at December 31 are summarized below. 2016 2015 ($ in Thousands) Commercial and industrial $ 6,489,014 $ 6,190,683 Commercial real estate — owner occupied 897,724 918,212 Commercial and business lending 7,386,738 7,108,895 Commercial real estate — investor 3,574,732 3,234,266 Real estate construction 1,432,497 1,162,145 Commercial real estate lending 5,007,229 4,396,411 Total commercial 12,393,967 11,505,306 Residential mortgage 6,332,327 5,783,267 Home equity 934,443 1,005,802 Other consumer 393,979 419,968 Total consumer 7,660,749 7,209,037 Total loans $ 20,054,716 $ 18,714,343
Loans And Leases Receivable Related Parties	The Corporation has granted loans to their directors, executive officers, or their related interests. These loans were made on substantially the same terms, including rates and collateral, as those prevailing at the time for comparable transactions with other unrelated customers, and do not involve more than a normal risk of collection. These loans to related parties are summarized below. 2016 ($ in Thousands) Balance at beginning of year $ 36,597 New loans 10,677 Repayments (11,089 ) Change due to status of executive officers and directors (8,596 ) Balance at end of year $ 27,589
Commercial and consumer loans by credit quality indicator	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 loans $ 19,251,353 $ 176,918 $ 351,142 $ 275,303 $ 20,054,716 The following table presents commercial and consumer loans by credit quality indicator at December 31, 2015 . Pass Special Mention Potential Problem Nonaccrual Total ($ in Thousands) Commercial and industrial $ 5,522,809 $ 341,169 $ 233,130 $ 93,575 $ 6,190,683 Commercial real estate - owner occupied 835,572 38,885 35,706 8,049 918,212 Commercial and business lending 6,358,381 380,054 268,836 101,624 7,108,895 Commercial real estate - investor 3,153,703 45,976 25,944 8,643 3,234,266 Real estate construction 1,157,034 252 3,919 940 1,162,145 Commercial real estate lending 4,310,737 46,228 29,863 9,583 4,396,411 Total commercial 10,669,118 426,282 298,699 111,207 11,505,306 Residential mortgage 5,727,437 1,552 2,796 51,482 5,783,267 Home equity 988,574 1,762 222 15,244 1,005,802 Other consumer 419,087 556 — 325 419,968 Total consumer 7,135,098 3,870 3,018 67,051 7,209,037 Total loans $ 17,804,216 $ 430,152 $ 301,717 $ 178,258 $ 18,714,343
Summarized details of Loans	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 loans $ 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, $224 million or 81% were current with respect to payment at December 31, 2016 . The following table presents loans by past due status at December 31, 2015 . Current 30-59 Days Past Due 60-89 Days Past Due 90 Days or More Past Due (a) Nonaccrual (b) Total ($ in Thousands) Commercial and industrial $ 6,095,848 $ 602 $ 409 $ 249 $ 93,575 $ 6,190,683 Commercial real estate - owner occupied 903,021 7,142 — — 8,049 918,212 Commercial and business lending 6,998,869 7,744 409 249 101,624 7,108,895 Commercial real estate - investor 3,225,332 291 — — 8,643 3,234,266 Real estate construction 1,160,909 270 26 — 940 1,162,145 Commercial real estate lending 4,386,241 561 26 — 9,583 4,396,411 Total commercial 11,385,110 8,305 435 249 111,207 11,505,306 Residential mortgage 5,726,855 4,491 439 — 51,482 5,783,267 Home equity 982,639 6,190 1,729 — 15,244 1,005,802 Other consumer 416,374 1,195 675 1,399 325 419,968 Total consumer 7,125,868 11,876 2,843 1,399 67,051 7,209,037 Total loans $ 18,510,978 $ 20,181 $ 3,278 $ 1,648 $ 178,258 $ 18,714,343 (a) The recorded investment in loans past due 90 days or more and still accruing totaled $2 million at December 31, 2015 (the same as the reported balances for the accruing loans noted above). (b) Of the total nonaccrual loans, $124 million or 69% were current with respect to payment at December 31, 2015 .
Summarized details of impaired Loans	The following table presents impaired loans at December 31, 2016 . Recorded Unpaid Related Average Interest ($ 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 $ 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 $ 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 impaired 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 . The following table presents impaired loans at December 31, 2015 . Recorded Investment Unpaid Principal Balance Related Allowance Average Recorded Investment Interest Income Recognized ($ in Thousands) Loans with a related allowance Commercial and industrial $ 57,785 $ 59,409 $ 8,162 $ 46,833 $ 855 Commercial real estate — owner occupied 9,705 9,804 448 10,087 412 Commercial and business lending 67,490 69,213 8,610 56,920 1,267 Commercial real estate — investor 27,822 29,444 1,831 28,278 1,914 Real estate construction 1,450 2,154 453 1,667 66 Commercial real estate lending 29,272 31,598 2,284 29,945 1,980 Total commercial 96,762 100,811 10,894 86,865 3,247 Residential mortgage 66,590 71,084 12,462 68,183 2,374 Home equity 21,769 23,989 10,118 22,624 1,147 Other consumer 1,154 1,225 195 1,199 30 Total consumer 89,513 96,298 22,775 92,006 3,551 Total loans $ 186,275 $ 197,109 $ 33,669 $ 178,871 $ 6,798 Loans with no related allowance Commercial and industrial $ 65,083 $ 72,259 $ — $ 79,573 $ 1,657 Commercial real estate — owner occupied 6,221 6,648 — 6,534 15 Commercial and business lending 71,304 78,907 — 86,107 1,672 Commercial real estate — investor 2,736 2,840 — 2,763 90 Real estate construction — — — — — Commercial real estate lending 2,736 2,840 — 2,763 90 Total commercial 74,040 81,747 — 88,870 1,762 Residential mortgage 4,762 5,033 — 4,726 126 Home equity 544 544 — 544 30 Other consumer — — — — — Total consumer 5,306 5,577 — 5,270 156 Total loans $ 79,346 $ 87,324 $ — $ 94,140 $ 1,918 Total Commercial and industrial $ 122,868 $ 131,668 $ 8,162 $ 126,406 $ 2,512 Commercial real estate — owner occupied 15,926 16,452 448 16,621 427 Commercial and business lending 138,794 148,120 8,610 143,027 2,939 Commercial real estate — investor 30,558 32,284 1,831 31,041 2,004 Real estate construction 1,450 2,154 453 1,667 66 Commercial real estate lending 32,008 34,438 2,284 32,708 2,070 Total commercial 170,802 182,558 10,894 175,735 5,009 Residential mortgage 71,352 76,117 12,462 72,909 2,500 Home equity 22,313 24,533 10,118 23,168 1,177 Other consumer 1,154 1,225 195 1,199 30 Total consumer 94,819 101,875 22,775 97,276 3,707 Total impaired loans (a) $ 265,621 $ 284,433 $ 33,669 $ 273,011 $ 8,716 (a) The net recorded investment (defined as recorded investment, net of the related allowance) of the impaired loans represented 82% of the unpaid principal balance at December 31, 2015 .
Nonaccrual and performing restructured loans	The following table presents nonaccrual and performing restructured loans by loan portfolio. December 31, 2016 December 31, 2015 December 31, 2014 Performing Restructured Loans Nonaccrual Restructured Loans (a) Performing Restructured Loans Nonaccrual Restructured Loans (a) Performing Restructured Loans Nonaccrual Restructured Loans (a) ($ in Thousands) Commercial and industrial $ 31,884 $ 1,276 $ 29,293 $ 1,714 $ 33,892 $ 3,260 Commercial real estate — owner occupied 5,490 2,220 7,877 2,703 10,454 5,656 Commercial real estate — investor 15,289 924 21,915 3,936 23,127 15,216 Real estate construction 359 150 510 177 727 2,438 Residential mortgage 18,100 21,906 19,870 24,592 20,833 26,049 Home equity 7,756 2,877 7,069 4,522 8,209 4,838 Other consumer 979 32 829 40 974 199 Total restructured loans $ 79,857 $ 29,385 $ 87,363 $ 37,684 $ 98,216 $ 57,656 (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 years ended December 31, 2016 , 2015 and 2014 , respectively, and the recorded investment and unpaid principal balance as of December 31, 2016 , 2015 and 2014 . Year Ended December 31, 2016 Year Ended December 31, 2015 Year Ended December 31, 2014 Number of Loans Recorded Investment (a) Unpaid Principal Balance (b) Number of Loans Recorded Investment (a) Unpaid Principal Balance (b) Number Recorded (a) Unpaid (b) ($ in Thousands) Commercial and industrial 8 $ 1,509 $ 1,526 12 $ 2,219 $ 2,900 15 $ 7,681 $ 7,711 Commercial real estate — owner occupied 1 116 122 5 3,694 3,901 4 1,465 1,625 Commercial real estate — investor — — — 5 21,573 21,640 6 6,097 6,521 Real estate construction 1 65 91 4 78 79 2 15 15 Residential mortgage 63 5,535 5,792 97 10,464 10,996 163 19,675 20,454 Home equity 57 2,030 2,084 88 3,103 3,249 117 3,913 4,308 Other consumer 1 15 16 — — — 2 24 26 Total 131 $ 9,270 $ 9,631 211 $ 41,131 $ 42,765 309 $ 38,870 $ 40,660 (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 year ended December 31, 2016 , 2015 and 2014 , respectively, as well as the recorded investment in these restructured loans as of December 31, 2016 , 2015 and 2014 , respectively. Year Ended December 31, 2016 Year Ended December 31, 2015 Year Ended December 31, 2014 Number of Loans Recorded Investment Number of Loans Recorded Investment Number of Recorded ($ in Thousands) Commercial and industrial — $ — 2 $ 197 1 $ 52 Commercial real estate — owner occupied — — — — 3 785 Commercial real estate — investor — — — — 13 6,200 Real estate construction — — — — 1 160 Residential mortgage 44 4,102 61 6,815 80 10,032 Home equity 23 457 28 1,220 54 1,802 Other consumer 1 15 — — 3 34 Total 68 $ 4,574 91 $ 8,232 155 $ 19,065
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 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: Individually evaluated for impairment $ 20,836 $ — $ 3,117 $ — $ 147 $ 3 $ — $ 24,103 Collectively evaluated for impairment 119,290 14,034 42,168 26,932 26,899 20,361 4,548 254,232 Total allowance for loan losses $ 140,126 $ 14,034 $ 45,285 $ 26,932 $ 27,046 $ 20,364 $ 4,548 $ 278,335 Loans: Individually evaluated for impairment $ 180,965 $ 8,439 $ 17,322 $ — $ 7,033 $ 650 $ — $ 214,409 Collectively evaluated for impairment 6,308,049 889,285 3,557,410 1,432,497 6,325,294 933,793 393,979 19,840,307 Total loans $ 6,489,014 $ 897,724 $ 3,574,732 $ 1,432,497 $ 6,332,327 $ 934,443 $ 393,979 $ 20,054,716 For comparison purposes, a summary of the changes in the allowance for loan losses by portfolio segment for the year ended December 31, 2015 , 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, 2014 $ 117,635 $ 16,510 $ 46,333 $ 20,999 $ 31,926 $ 26,464 $ 6,435 $ 266,302 Charge offs (27,687 ) (2,645 ) (4,645 ) (750 ) (5,636 ) (7,048 ) (3,869 ) (52,280 ) Recoveries 9,821 921 4,157 2,268 1,077 3,233 765 22,242 Net charge offs (17,866 ) (1,724 ) (488 ) 1,518 (4,559 ) (3,815 ) (3,104 ) (30,038 ) Provision for loan losses 30,190 3,894 (2,827 ) 2,749 894 906 2,194 38,000 December 31, 2015 $ 129,959 $ 18,680 $ 43,018 $ 25,266 $ 28,261 $ 23,555 $ 5,525 $ 274,264 Allowance for loan losses: Individually evaluated for impairment $ 7,522 $ — $ 229 $ — $ 166 $ 46 $ — $ 7,963 Collectively evaluated for impairment 122,437 18,680 42,789 25,266 28,095 23,509 5,525 266,301 Total allowance for loan losses $ 129,959 $ 18,680 $ 43,018 $ 25,266 $ 28,261 $ 23,555 $ 5,525 $ 274,264 Loans: Individually evaluated for impairment $ 91,569 $ 6,221 $ 5,460 $ — $ 6,956 $ 1,281 $ — $ 111,487 Collectively evaluated for impairment 6,099,114 911,991 3,228,806 1,162,145 5,776,311 1,004,521 419,968 18,602,856 Total loans $ 6,190,683 $ 918,212 $ 3,234,266 $ 1,162,145 $ 5,783,267 $ 1,005,802 $ 419,968 $ 18,714,343
Changes in the allowance for unfunded commitments	A summary of the changes in the allowance for unfunded commitments was as follows. Years Ended December 31, 2016 2015 2014 ($ in Thousands) Allowance for Unfunded Commitments: Balance at beginning of period $ 24,400 $ 24,900 $ 21,900 Provision for unfunded commitments 1,000 (500 ) 3,000 Balance at end of period $ 25,400 $ 24,400 $ 24,900

Goodwill and Intangible Assets

Goodwill and Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2016
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. 2016 2015 2014 ($ in Thousands) Core deposit intangibles: Gross carrying amount $ 4,385 $ 19,545 $ 36,230 Accumulated amortization (4,273 ) (19,152 ) (34,433 ) Net book value $ 112 $ 393 $ 1,797 Amortization during the year $ 281 $ 1,404 $ 2,868 Other intangibles: Gross carrying amount $ 32,410 $ 31,398 $ 19,283 Accumulated amortization (17,145 ) (15,333 ) (13,643 ) Net book value $ 15,265 $ 16,065 $ 5,640 Additions during the period $ 1,012 $ 12,115 $ — Amortization during the year $ 1,812 $ 1,690 $ 879
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. 2016 2015 2014 ($ in Thousands) Mortgage servicing rights Mortgage servicing rights at beginning of year $ 62,150 $ 61,379 $ 64,193 Additions 12,262 12,372 8,253 Amortization (12,327 ) (11,601 ) (11,067 ) Mortgage servicing rights at end of year $ 62,085 $ 62,150 $ 61,379 Valuation allowance at beginning of year (809 ) (1,234 ) (913 ) (Additions) recoveries, net 200 425 (321 ) Valuation allowance at end of year (609 ) (809 ) (1,234 ) Mortgage servicing rights, net $ 61,476 $ 61,341 $ 60,145 Fair value of mortgage servicing rights $ 73,149 $ 70,686 $ 66,342 Portfolio of residential mortgage loans serviced for others (“servicing portfolio”) $ 7,974,742 $ 7,915,224 $ 7,999,294 Mortgage servicing rights, net to servicing portfolio 0.77 % 0.77 % 0.75 % Mortgage servicing rights expense (1) $ 12,127 $ 11,176 $ 11,388 (1) 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 December 31, 2016 . 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 Core Deposit Intangibles Other Intangibles Mortgage Servicing Rights ($ in Thousands) Year ending December 31, 2017 $ 112 $ 1,786 $ 9,627 2018 — 1,756 8,134 2019 — 1,457 6,878 2020 — 1,340 5,840 2021 — 1,316 4,970 Beyond 2021 — 7,610 26,636 Total Estimated Amortization Expense $ 112 $ 15,265 $ 62,085

Premises and Equipment (Tables)

Premises and Equipment (Tables)	12 Months Ended
	Dec. 31, 2016
Property, Plant and Equipment [Abstract]
Summary of Premises and Equipment	A summary of premises and equipment at December 31 was as follows. 2016 2015 Estimated Useful Lives Cost Accumulated Depreciation Net Book Value Net Book Value ($ in Thousands) Land — $ 57,471 $ — $ 57,471 $ 52,104 Land improvements 3 – 15 years 12,572 5,929 6,643 6,661 Buildings 5 – 39 years 332,256 130,104 202,152 141,432 Computers 3 – 5 years 42,190 33,139 9,051 6,372 Furniture, fixtures and other equipment 3 – 15 years 162,253 119,704 42,549 49,794 Leasehold improvements 3 – 15 years 34,959 22,510 12,449 11,243 Total premises and equipment $ 641,701 $ 311,386 $ 330,315 $ 267,606
Minimum annual rentals and commitments under noncancelable operating leases	The approximate minimum annual rentals and commitments under these noncancelable agreements and leases with remaining terms in excess of one year are as follows. ($ in Thousands) 2017 $ 9,711 2018 9,665 2019 9,115 2020 8,133 2021 7,336 Thereafter 20,940 Total $ 64,900

Deposits (Tables)

Deposits (Tables)	12 Months Ended
	Dec. 31, 2016
Deposits [Abstract]
Deposits by type	The distribution of deposits at December 31 was as follows. 2016 2015 ($ in Thousands) Noninterest-bearing demand $ 5,392,208 $ 5,562,466 Savings 1,431,494 1,334,420 Interest-bearing demand 4,687,656 3,445,000 Money market 8,770,963 9,102,977 Brokered CDs 52,725 42,443 Other time 1,553,402 1,520,359 Total deposits $ 21,888,448 $ 21,007,665
Time deposits by maturity	Aggregate annual maturities of all time deposits at December 31, 2016 , are as follows. Maturities During Year Ending December 31, ($ in Thousands) 2017 $ 932,179 2018 276,642 2019 185,465 2020 131,820 2021 76,740 Thereafter 3,281 Total $ 1,606,127

Short-term Funding (Tables)

Short-term Funding (Tables)	12 Months Ended
	Dec. 31, 2016
Short-term Debt [Abstract]
Short-term funding	The components of short-term funding (funding with original contractual maturities of one year or less) at December 31 were as follows. 2016 2015 ($ in Thousands) Federal funds purchased $ 208,150 $ 47,870 Securities sold under agreements to repurchase 300,197 383,568 Federal funds purchased and securities sold under agreements to repurchase 508,347 431,438 FHLB advances 482,000 335,000 Commercial paper 101,688 67,978 Other short-term funding 583,688 402,978 Total short-term funding $ 1,092,035 $ 834,416
Schedule of Repurchase Agreements	The remaining contractual maturity of the securities sold under agreements to repurchase in the consolidated balance sheets 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 ($ in Thousands) December 31, 2016 Repurchase agreements Agency mortgage-related securities $ 300,197 $ — $ — $ — $ 300,197 Total $ 300,197 $ — $ — $ — $ 300,197 December 31, 2015 Repurchase agreements Agency mortgage-related securities $ 383,568 $ — $ — $ — $ 383,568 Total $ 383,568 $ — $ — $ — $ 383,568

Long-term Funding (Tables)

Long-term Funding (Tables)	12 Months Ended
	Dec. 31, 2016
Debt Disclosure [Abstract]
Long-term Funding	The components of long-term funding (funding with original contractual maturities greater than one year) at December 31 were as follows. 2016 2015 ($ in Thousands) FHLB advances $ 2,265,188 $ 1,750,225 Senior notes, at par 250,000 680,000 Subordinated notes, at par 250,000 250,000 Other long-term funding and capitalized costs (3,393 ) (4,061 ) Total long-term funding $ 2,761,795 $ 2,676,164
Maturities of Long-term funding	The table below summarizes the maturities of the Corporation’s long-term funding at December 31, 2016 . Year ($ in Thousands) 2017 $ 5 2018 1,865,000 2019 498,939 2020 164 2021 150,000 Thereafter 247,687 Total long-term funding $ 2,761,795

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2016
Compensation and Retirement Disclosure [Abstract]
Fair value assumptions of stock options	The following assumptions were used in estimating the fair value for options granted in 2016 , 2015 and 2014 . 2016 2015 2014 Dividend yield 2.50 % 2.00 % 2.00 % Risk-free interest rate 2.00 % 2.00 % 2.00 % Weighted average expected volatility 25.00 % 20.00 % 20.00 % Weighted average expected life 5.5 years 6 years 6 years Weighted average per share fair value of options $3.36 $3.08 $3.00
Summary of Company's Stock Option Activities	A summary of the Corporation’s stock option activity for the year ended December 31, 2016 is presented below. Stock Options Shares Weighted Average Exercise Price Weighted Average Remaining Contractual Term Aggregate Intrinsic Value (000s) Outstanding at December 31, 2015 6,629,143 $ 17.22 6.24 $ 18,730 Granted 1,302,298 17.45 Exercised (1,389,146 ) 14.81 Forfeited or expired (184,452 ) 21.62 Outstanding at December 31, 2016 6,357,843 $ 17.67 6.10 $ 47,902 Options Exercisable at December 31, 2016 3,632,749 $ 17.85 4.45 $ 28,109
Summary of Company's Nonvested Stock Option Activities	The following table summarizes information about the Corporation’s nonvested stock option activity for the year ended December 31, 2016. Nonvested Stock Options Shares Weighted Average Nonvested at December 31, 2015 2,438,898 $ 3.15 Granted 1,302,298 3.36 Vested (909,361 ) 3.27 Forfeited (106,741 ) 3.39 Nonvested at December 31, 2016 2,725,094 $ 3.21
Summary of Restricted Stock Awards Activity (Excluding Salary Shares)	The following table summarizes information about the Corporation’s restricted stock activity for the year ended December 31, 2016. Restricted Stock Shares Weighted Average Grant Date Fair Value Outstanding at December 31, 2015 2,250,028 $ 17.03 Granted 1,095,596 17.58 Vested (864,617 ) 16.62 Forfeited (103,627 ) 17.59 Outstanding at December 31, 2016 2,377,380 $ 17.40

Retirement Plans (Tables)

Retirement Plans (Tables)	12 Months Ended
	Dec. 31, 2016
Defined Benefit Pension Plans and Defined Benefit Postretirement Plans Disclosure [Abstract]
Change in Benefit Obligation	The funded status and amounts recognized in the 2016 and 2015 consolidated balance sheets, as measured on December 31, 2016 and 2015 , respectively, for the Retirement Account and Postretirement Plans were as follows. Retirement Account Plan Postretirement Plan Retirement Account Plan Postretirement Plan 2016 2016 2015 2015 ($ in Thousands) Change in Fair Value of Plan Assets Fair value of plan assets at beginning of year $ 289,599 $ — $ 303,496 $ — Actual return on plan assets 17,097 — 495 — Employer contributions — 248 — 264 Gross benefits paid (10,978 ) (248 ) (14,392 ) (264 ) Fair value of plan assets at end of year* $ 295,718 $ — $ 289,599 $ — Change in Benefit Obligation Net benefit obligation at beginning of year $ 171,783 $ 3,436 $ 171,333 $ 3,578 Service cost 6,780 — 11,257 — Interest cost 7,121 142 6,617 141 Plan amendments (823 ) (936 ) — — Actuarial (gain) loss 2,942 9 (3,032 ) (19 ) Gross benefits paid (10,978 ) (248 ) (14,392 ) (264 ) Net benefit obligation at end of year* $ 176,825 $ 2,403 $ 171,783 $ 3,436 Funded (unfunded) status $ 118,893 $ (2,403 ) $ 117,816 $ (3,436 ) Noncurrent assets 118,893 — 117,816 — Current liabilities — (215 ) — (274 ) Noncurrent liabilities — (2,188 ) — (3,162 ) Asset (Liability) Recognized in the Consolidated Balance Sheets $ 118,893 $ (2,403 ) $ 117,816 $ (3,436 ) * The fair value of the plan assets represented 167% and 169% of the net benefit obligation of the pension plan at December 31, 2016 and 2015 , respectively.
AOCI Components	Amounts recognized in accumulated other comprehensive loss, net of tax, as of December 31, 2016 and 2015 follow. Retirement Account Plan Postretirement Plan Retirement Account Plan Postretirement Plan 2016 2016 2015 2015 ($ in Thousands) Prior service cost $ (342 ) $ (580 ) $ 122 $ — Net actuarial loss 35,443 79 32,879 73 Amount not yet recognized in net periodic benefit cost, but recognized in accumulated other comprehensive loss $ 35,101 $ (501 ) $ 33,001 $ 73
Changes in OCI	Other changes in plan assets and benefit obligations recognized in other comprehensive income (loss) (“OCI”), net of tax, in 2016 and 2015 were as follows. Retirement Account Postretirement Retirement Account Postretirement 2016 2016 2015 2015 ($ in Thousands) Net gain (loss) $ (6,132 ) $ (9 ) $ (17,911 ) $ 19 Amortization of prior service cost (73 ) — 50 — Amortization of actuarial gain 2,115 — 2,256 — Plan amendments 823 936 — — Income tax (expense) benefit 1,168 (353 ) 5,880 (7 ) Total Recognized in OCI $ (2,099 ) $ 574 $ (9,725 ) $ 12
Net period benefit cost for the pension and postretirement plans	The components of net periodic benefit cost for the Retirement Account Plan and Postretirement Plans for 2016 , 2015 , and 2014 were as follows. Retirement Account Postretirement Retirement Account Postretirement Retirement Account Postretirement 2016 2016 2015 2015 2014 2014 ($ in Thousands) Service cost $ 6,780 $ — $ 11,257 $ — $ 11,058 $ — Interest cost 7,121 142 6,617 141 7,132 150 Expected return on plan assets (20,287 ) — (21,438 ) — (19,922 ) — Amortization of: Prior service cost (73 ) — 50 — 58 — Actuarial (gain) loss 2,115 — 2,256 — 1,384 (35 ) Total net pension cost $ (4,344 ) $ 142 $ (1,258 ) $ 141 $ (290 ) $ 115
Weighted Average Benefit Assumptions	Retirement Account Plan Postretirement Plan Retirement Account Plan Postretirement Plan 2016 2016 2015 2015 Weighted average assumptions used to determine benefit obligations: Discount rate 4.10 % 4.10 % 4.30 % 4.30 % Rate of increase in compensation levels 4.00 % NA 4.00 % NA Weighted average assumptions used to determine net periodic benefit costs: Discount rate 4.30 % 4.30 % 4.00 % 4.00 % Rate of increase in compensation levels 4.00 % NA 4.00 % NA Expected long-term rate of return on plan assets 7.00 % NA 7.50 % NA
Plan Asset Allocation Percentages	The asset allocation for the Retirement Account Plan as of the December 31, 2016 and 2015 measurement dates, respectively, by asset category were as follows. Asset Category 2016 2015 Equity securities 60 % 60 % Fixed income securities 39 % 40 % Other 1 % — % Total 100 % 100 %
Pension Plan Investments	Based on these inputs, the following table summarizes the fair value of the Retirement Account Plan’s investments as of December 31, 2016 and 2015 . Fair Value Measurements Using December 31, 2016 Level 1 Level 2 Level 3 ($ in Thousands) Retirement Account Plan Investments: Money market account $ 3,624 $ 3,624 $ — $ — Common /collective trust funds 126,741 126,741 — — Mutual funds 165,353 165,353 — — Total Retirement Account Plan Investments $ 295,718 $ 295,718 $ — $ — Fair Value Measurements Using December 31, 2015 Level 1 Level 2 Level 3 ($ in Thousands) Retirement Account Plan Investments: Money market account $ 481 $ 481 $ — $ — Common /collective trust funds 120,136 120,136 — — Mutual funds 168,982 168,982 — — Total Retirement Account Plan Investments $ 289,599 $ 289,599 $ — $ —
Expected Benefit Payments	The projected benefit payments for the Retirement Account and Postretirement Plans at December 31, 2016 , reflecting expected future services, were as follows. The projected benefit payments were calculated using the same assumptions as those used to calculate the benefit obligations listed above. Retirement Account Plan Postretirement Plan ($ in Thousands) Estimated future benefit payments: 2017 $ 14,829 $ 215 2018 14,538 199 2019 14,169 179 2020 13,815 177 2021 13,651 174 2022-2026 71,433 815
One Percentage Point Change in Assumed Health Care Cost	A one percentage point change in the assumed health care cost trend rate would have the following effect. 2016 2015 100 bp Increase 100 bp Decrease 100 bp Increase 100 bp Decrease ($ in Thousands) Effect on total of service and interest cost $ 7 $ (6 ) $ 15 $ (13 ) Effect on postretirement benefit obligation $ 173 $ (149 ) $ 357 $ (310 )

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Current and Deferred Income Tax Expense (Benefit)	The current and deferred amounts of income tax expense (benefit) were as follows. Years Ended December 31, 2016 2015 2014 ($ in Thousands) Current: Federal $ 73,781 $ 82,449 $ 74,646 State 2,885 2,560 1,000 Total current 76,666 85,009 75,646 Deferred: Federal 3,338 (10,606 ) (805 ) State 7,318 7,084 10,695 Total deferred 10,656 (3,522 ) 9,890 Total income tax expense $ 87,322 $ 81,487 $ 85,536
Schedule of Deferred Tax Assets and Liabilities	Temporary differences between the amounts reported in the financial statements and the tax bases of assets and liabilities resulted in deferred taxes. Deferred tax assets and liabilities at December 31 were as follows. 2016 2015 ($ in Thousands) Deferred tax assets: Allowance for loan losses $ 100,891 $ 106,258 Allowance for other losses 11,080 10,906 Accrued liabilities 5,969 6,802 Deferred compensation 33,169 31,677 State net operating losses 7,882 14,154 Nonaccrual interest 1,085 1,901 Net unrealized losses on available-for-sale securities 16,980 219 Net unrealized losses on pension and postretirement benefits 21,218 20,404 Other 8,128 5,811 Total deferred tax assets 206,402 198,132 Deferred tax liabilities: FHLB stock dividends — 2,165 Prepaid expenses 70,943 69,396 Goodwill 27,365 25,770 Mortgage banking activities 17,569 15,704 Deferred loan fee income 16,474 17,770 State deferred taxes 3,800 6,366 Lease financing 1,975 3,042 Bank premises and equipment 7,698 7,491 Other 8,594 9,062 Total deferred tax liabilities 154,418 156,766 Net deferred tax assets $ 51,984 $ 41,366
Schedule of Effective Income Tax Rate Reconciliation	The effective income tax rate differs from the statutory federal tax rate. The major reasons for this difference were as follows. 2016 2015 2014 Federal income tax rate at statutory rate 35.0 % 35.0 % 35.0 % Increases (decreases) resulting from: Tax-exempt interest and dividends (4.8 )% (5.0 )% (4.6 )% State income taxes (net of federal benefit) 2.3 % 2.3 % 2.8 % Bank owned life insurance (1.7 )% (1.2 )% (1.7 )% Tax effect of tax credits and benefits, net of related expenses (0.8 )% (0.5 )% (1.4 )% Tax reserve adjustments 0.3 % (0.6 )% 0.7 % Other 0.1 % 0.2 % 0.2 % Effective income tax rate 30.4 % 30.2 % 31.0 %
Summary Unrecognized Tax Benefits	A reconciliation of the beginning and ending amount of unrecognized tax benefits was as follows. 2016 2015 ($ in Millions) Balance at beginning of year $ 9 $ 9 Subtractions for tax positions related to prior years — (2 ) Additions for tax positions related to current year 1 2 Balance at end of year $ 10 $ 9

Derivative and Hedging Activi43

Derivative and Hedging Activities (Tables)	12 Months Ended
	Dec. 31, 2016
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 derivative instruments to accommodate customer needs which are not designated as hedging instruments. December 31, 2016 December 31, 2015 Notional Amount Fair Value Balance Sheet Category Notional Amount Fair Balance Sheet ($ in Thousands) Interest rate-related instruments — customer and mirror $ 2,039,323 $ 33,671 Trading assets $ 1,665,965 $ 29,391 Trading assets Interest rate-related instruments — customer and mirror 2,039,323 (33,188 ) Trading liabilities 1,665,965 (30,886 ) Trading liabilities Foreign currency exchange forwards 109,675 2,002 Trading assets 72,976 1,532 Trading assets Foreign currency exchange forwards 106,251 (1,943 ) Trading liabilities 65,649 (1,398 ) Trading liabilities Commodity contracts 127,582 16,725 Trading assets 44,380 1,269 Trading assets Commodity contracts 128,368 (15,972 ) Trading liabilities 44,256 (1,146 ) 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. December 31, 2016 December 31, 2015 Notional Amount Fair Balance Sheet Notional Amount Fair Balance Sheet ($ in Thousands) Interest rate lock commitments (mortgage) $ 285,345 $ 206 Other assets $ 271,530 $ 958 Other assets Forward commitments (mortgage) 179,600 2,908 Other assets 231,798 403 Other assets Purchased options (time deposit) 80,554 2,576 Other assets 104,582 2,715 Other assets Written options (time deposit) 80,554 (2,576 ) Other liabilities 104,582 (2,715 ) 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 Year Ended December 31, 2016 2015 ($ in Thousands) Interest rate-related instruments — customer and mirror, net Capital market fees, net $ 1,978 $ 854 Interest rate lock commitments (mortgage) Mortgage banking, net (752 ) (989 ) Forward commitments (mortgage) Mortgage banking, net 2,505 2,838 Foreign currency exchange forwards Capital market fees, net (75 ) (49 ) Commodity contracts Capital market fees, net 630 123

Balance Sheet Offsetting (Table

Balance Sheet Offsetting (Tables)	12 Months Ended
	Dec. 31, 2016
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) 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 December 31, 2015 Derivative assets: Interest and commodity agreements $ 1,466 $ — $ 1,466 $ (1,466 ) $ — $ — Derivative liabilities: Interest and commodity agreements $ 30,200 $ — $ 30,200 $ (1,466 ) $ (28,734 ) $ —

Commitments, Off-Balance Shee45

Commitments, Off-Balance Sheet Arrangements, and Contingent Liabilities (Tables)	12 Months Ended
	Dec. 31, 2016
Commitments and Contingencies Disclosure [Abstract]
Summary of lending-related and other commitments	The following is a summary of lending-related commitments. 2016 2015 ($ in Thousands) Commitments to extend credit, excluding commitments to originate residential mortgage loans held for sale (1)(2) $ 8,131,131 $ 7,402,518 Commercial letters of credit (1) 7,923 9,945 Standby letters of credit (3) 259,632 296,508 (1) 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 December 31, 2016 and 2015 . (2) Interest rate lock commitments to originate residential mortgage loans held for sale are considered derivative instruments and are disclosed in Note 14 . (3) The Corporation has established a liability of $3 million at both December 31, 2016 and December 31, 2015 , as an estimate of the fair value of these financial instruments.
Summary of changes in the residential mortgage repurchase reserve	The following summarizes the changes in the mortgage repurchase reserve for the years ended as follows. 2016 2015 ($ in Thousands) Balance at beginning of year $ 1,197 $ 3,258 Repurchase provision expense 456 428 Adjustments to provision expense (750 ) (2,450 ) Charge offs, net (3 ) (39 ) Balance at end of year $ 900 $ 1,197

Parent Company Only Financial46

Parent Company Only Financial Information (Tables)	12 Months Ended
	Dec. 31, 2016
Condensed Financial Information of Parent Company Only Disclosure [Abstract]
Parent Company Balance Sheet	BALANCE SHEETS December 31, 2016 2015 ($ in Thousands) ASSETS Cash and due from banks $ 402,786 $ 610,862 Investment securities available for sale, at fair value 14,389 61,847 Investment in subsidiaries 3,248,763 3,211,685 Other assets 61,242 70,595 Total assets $ 3,727,180 $ 3,954,989 LIABILITIES AND STOCKHOLDERS’ EQUITY Commercial paper $ 101,688 $ 67,978 Senior notes, at par 250,000 680,000 Subordinated notes, at par 250,000 250,000 Long-term funding capitalized costs (3,393 ) (4,061 ) Total long-term funding 496,607 925,939 Accrued expenses and other liabilities 37,573 23,826 Total liabilities 635,868 1,017,743 Preferred equity 159,929 121,379 Common equity 2,931,383 2,815,867 Total stockholders’ equity 3,091,312 2,937,246 Total liabilities and stockholders’ equity $ 3,727,180 $ 3,954,989
Parent Company Income Statement	STATEMENTS OF INCOME For the Years Ended December 31, 2016 2015 2014 ($ in Thousands) INCOME Dividends from subsidiaries $ 188,000 $ 205,000 $ 223,000 Interest income on notes receivable — — 1,264 Other income 4,669 8,441 9,713 Total income 192,669 213,441 233,977 EXPENSE Interest expense on short and long-term funding 21,901 39,576 24,847 Other expense 4,289 4,684 776 Total expense 26,190 44,260 25,623 Income before income tax expense (benefit) and equity in undistributed net income (loss) of subsidiaries 166,479 169,181 208,354 Income tax expense (benefit) 3,468 (1,665 ) (5,801 ) Income before equity in undistributed net income (loss) of subsidiaries 163,011 170,846 214,155 Equity in undistributed net income (loss) of subsidiaries 37,263 17,455 (23,646 ) Net income 200,274 188,301 190,509 Preferred stock dividends 8,903 7,155 5,002 Net income available to common equity $ 191,371 $ 181,146 $ 185,507
Parent Company Statement of Cash Flows	STATEMENTS OF CASH FLOWS For the Years Ended December 31, 2016 2015 2014 ($ in Thousands) OPERATING ACTIVITIES Net income $ 200,274 $ 188,301 $ 190,509 Adjustments to reconcile net income to net cash provided by operating activities: (Increase) decrease in equity in undistributed net income of subsidiaries (37,263 ) (17,455 ) 23,646 Gain on sales of investment securities, net (466 ) — (214 ) Asset gain, net (793 ) (5,673 ) (5,609 ) Net change in other assets and other liabilities 19,708 (10,997 ) (14,022 ) Net cash provided by operating activities 181,460 154,176 194,310 INVESTING ACTIVITIES Proceeds from sales of investment securities 47,719 13,962 88,844 Net decrease in notes receivable — — 46,594 Purchase of other assets, net of disposals 2,211 11,964 10,930 Net cash provided by investing activities 49,930 25,926 146,368 FINANCING ACTIVITIES Net increase (decrease) in short-term funding 33,710 (6,319 ) 8,813 Repayment of long-term funding (430,000 ) — (155,000 ) Proceeds from issuance of long-term funding — — 496,030 Proceeds from issuance of common stock for stock-based compensation plans 21,748 20,054 13,228 Proceeds from issuance of preferred stock 97,066 62,966 — Redemption of preferred stock (58,903 ) — — Purchase of preferred stock (1,248 ) (1,335 ) (2,451 ) Purchase of common stock returned to authorized but unissued (20,007 ) (93,000 ) (150,498 ) Purchase of treasury stock — — (108,600 ) Purchase of treasury stock for tax withholding (5,074 ) (5,154 ) (3,712 ) Cash dividends on common stock (67,855 ) (62,400 ) (58,710 ) Cash dividends on preferred stock (8,903 ) (7,155 ) (5,002 ) Net cash provided by (used in) financing activities (439,466 ) (92,343 ) 34,098 Net increase (decrease) in cash and cash equivalents (208,076 ) 87,759 374,776 Cash and cash equivalents at beginning of year 610,862 523,103 148,327 Cash and cash equivalents at end of year $ 402,786 $ 610,862 $ 523,103

Regulatory Matters (Tables)

Regulatory Matters (Tables)	12 Months Ended
	Dec. 31, 2016
Regulatory Capital Requirements [Abstract]
Schedule of Compliance with Regulatory Capital Requirements under Banking Regulations	Actual For Capital Adequacy Purposes To Be Well Capitalized Under Prompt Corrective Action Provisions: (2) Amount Ratio (1) Amount Ratio (1) Amount Ratio (1) ($ in Thousands) As of December 31 , 2016 Associated Banc-Corp Total capital $ 2,706,760 12.68 % $ 1,707,276 ≥ 8.00 % Tier 1 capital 2,191,798 10.27 1,280,457 ≥ 6.00 % Common equity Tier 1 capital 2,032,587 9.52 960,343 ≥ 4.50 % Leverage 2,191,798 7.83 1,119,685 ≥ 4.00 % Associated Bank, N.A. Total capital $ 2,565,062 12.07 % $ 1,700,737 ≥ 8.00 % $ 2,125,921 ≥ 10.00 % Tier 1 capital 2,298,812 10.81 1,275,553 ≥ 6.00 % 1,700,737 ≥ 8.00 % Common equity Tier 1 capital 2,098,812 9.87 956,664 ≥ 4.50 % 1,381,849 ≥ 6.50 % Leverage 2,298,812 8.24 1,115,731 ≥ 4.00 % 1,394,663 ≥ 5.00 % As of December 31 , 2015 Associated Banc-Corp Total capital $ 2,515,861 12.62 % $ 1,594,397 ≥ 8.00 % Tier 1 capital 2,016,861 10.12 1,195,798 ≥ 6.00 % Common equity Tier 1 capital 1,897,944 9.52 896,848 ≥ 4.50 % Leverage 2,016,861 7.60 1,061,325 ≥ 4.00 % Associated Bank, N.A. Total capital $ 2,532,563 12.76 % $ 1,588,070 ≥ 8.00 % $ 1,985,088 ≥ 10.00 % Tier 1 capital 2,283,785 11.50 1,191,053 ≥ 6.00 % 1,588,070 ≥ 8.00 % Common equity Tier 1 capital 2,084,589 10.50 893,289 ≥ 4.50 % 1,290,307 ≥ 6.50 % Leverage 2,283,785 8.64 1,057,228 ≥ 4.00 % 1,321,535 ≥ 5.00 % (1) When fully phased-in on January 1, 2019, the Basel III capital rules include a capital conservation buffer of 2.5% that is added on top of each of the minimum risk-based capital ratios noted above. Implementation began on January 1, 2016 at the 0.625% level and will increase each subsequent January 1, until it reaches 2.5% on January 1, 2019. (2) Prompt corrective action provisions are not applicable at the bank holding company level.

Earnings Per Common Share (Tabl

Earnings Per Common Share (Tables)	12 Months Ended
	Dec. 31, 2016
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 Years Ended December 31, 2016 2015 2014 (In thousands, except per share data) Net income $ 200,274 $ 188,301 $ 190,509 Preferred stock dividends (8,903 ) (7,155 ) (5,002 ) Net income available to common equity $ 191,371 $ 181,146 $ 185,507 Common shareholder dividends (67,100 ) (61,774 ) (58,123 ) Unvested share-based payment awards (755 ) (626 ) (587 ) Undistributed earnings $ 123,516 $ 118,746 $ 126,797 Undistributed earnings allocated to common shareholders 122,205 117,498 125,646 Undistributed earnings allocated to unvested share-based payment awards 1,311 1,248 1,151 Undistributed earnings $ 123,516 $ 118,746 $ 126,797 Basic Distributed earnings to common shareholders $ 67,100 $ 61,774 $ 58,123 Undistributed earnings allocated to common shareholders 122,205 117,498 125,646 Total common shareholders earnings, basic $ 189,305 $ 179,272 $ 183,769 Diluted Distributed earnings to common shareholders $ 67,100 $ 61,774 $ 58,123 Undistributed earnings allocated to common shareholders 122,205 117,498 125,646 Total common shareholders earnings, diluted $ 189,305 $ 179,272 $ 183,769 Weighted average common shares outstanding 148,769 149,350 157,286 Effect of dilutive common stock awards 1,192 1,253 968 Diluted weighted average common shares outstanding 149,961 150,603 158,254 Basic earnings per common share $ 1.27 $ 1.20 $ 1.17 Diluted earnings per common share $ 1.26 $ 1.19 $ 1.16

Segment Reporting (Tables)

Segment Reporting (Tables)	12 Months Ended
	Dec. 31, 2016
Segment Reporting [Abstract]
Selected segment information	Information about the Corporation’s segments is presented below. Segment Income Statement Data Corporate and Commercial Specialty Community, Consumer, and Business Risk Management and Shared Services Consolidated Total For the Years Ended December 31, ($ in Thousands) 2016 Net interest income $ 328,603 $ 350,551 $ 28,119 $ 707,273 Noninterest income 47,776 277,942 27,165 352,883 Total revenue 376,379 628,493 55,284 1,060,156 Credit provision* 50,397 24,185 (4,582 ) 70,000 Noninterest expense 148,493 502,285 51,782 702,560 Income before income taxes 177,489 102,023 8,084 287,596 Income tax expense (benefit) 59,261 35,708 (7,647 ) 87,322 Net income $ 118,228 $ 66,315 $ 15,731 $ 200,274 Return on average allocated capital (ROCET1)** 11.0 % 10.5 % 2.8 % 9.9 % 2015 Net interest income $ 310,072 $ 349,134 $ 17,072 $ 676,278 Noninterest income 46,742 265,503 17,112 329,357 Total revenue 356,814 614,637 34,184 1,005,635 Credit provision* 41,913 25,614 (30,027 ) 37,500 Noninterest expense 141,912 492,284 64,151 698,347 Income before income taxes 172,989 96,739 60 269,788 Income tax expense (benefit) 59,200 33,859 (11,572 ) 81,487 Net income $ 113,789 $ 62,880 $ 11,632 $ 188,301 Return on average allocated capital (ROCET1)** 11.6 % 9.8 % 2.1 % 9.9 % 2014 Net interest income $ 296,717 $ 310,444 $ 73,806 $ 680,967 Noninterest income 49,213 221,430 20,218 290,861 Total revenue 345,930 531,874 94,024 971,828 Credit provision* 46,857 23,934 (54,791 ) 16,000 Noninterest expense 148,476 463,235 68,072 679,783 Income before income taxes 150,597 44,705 80,743 276,045 Income tax expense 50,039 15,647 19,850 85,536 Net income $ 100,558 $ 29,058 $ 60,893 $ 190,509 Return on average allocated capital (ROCET1)** 11.1 % 5.1 % 13.9 % 9.9 % Segment Balance Sheet Data Corporate and Commercial Specialty Community, Consumer, and Business Risk Management and Shared Services Consolidated Total Average Balance for: ($ in Thousands) 2016 Average earning assets $ 10,178,813 $ 9,309,028 $ 6,538,820 $ 26,026,661 Average loans 10,169,300 9,307,723 173,644 19,650,667 Average deposits 5,904,238 11,451,759 3,649,775 21,005,772 Average allocated capital (CET1)** $ 1,070,598 $ 629,540 $ 240,253 $ 1,940,391 2015 Average earning assets $ 9,383,971 $ 8,810,015 $ 6,377,101 $ 24,571,087 Average loans 9,374,191 8,809,673 68,400 18,252,264 Average deposits 5,856,530 10,898,602 3,147,955 19,903,087 Average allocated capital (CET1)** $ 977,406 $ 640,181 $ 216,010 $ 1,833,597 2014 Average earning assets $ 8,927,401 $ 7,840,352 $ 5,992,375 $ 22,760,128 Average loans 8,915,498 7,840,352 83,144 16,838,994 Average deposits 5,148,195 10,061,495 2,437,394 17,647,084 Average allocated capital (CET1)** $ 903,500 $ 564,303 $ 402,806 $ 1,870,609 * The consolidated credit provision is equal to the actual reported provision for credit losses. ** The Federal Reserve establishes capital adequacy requirements for the Corporation. Average allocated capital represents average common equity Tier 1, as defined by the Federal Reserve. For segment reporting purposes, the ROCET1, a non-GAAP financial measure, reflects return on average allocated common equity Tier 1 (“CET1”). 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 Comprehensi50

Accumulated Other Comprehensive Income (Loss) (Tables)	12 Months Ended
	Dec. 31, 2016
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Summary of activity in accumulated other comprehensive income (loss)	The following table summarizes the components of accumulated other comprehensive income (loss) at December 31, 2016 , 2015 , and 2014 , changes during the years then ended, and reclassifications out of accumulated other comprehensive income (loss) during the years ended December 31, 2016 , 2015 , and 2014 , respectively. Investments Securities Available For Sale Defined Benefit Pension and Postretirement Obligations Accumulated Other Comprehensive Income (Loss) ($ in Thousands) Balance December 31, 2013 $ (11,396 ) $ (12,848 ) $ (24,244 ) Other comprehensive income (loss) before reclassifications 49,038 (18,428 ) 30,610 Amounts reclassified from accumulated other comprehensive income (loss): Investment securities gain, net (494 ) — (494 ) Personnel expense — 1,407 1,407 Income tax (expense) benefit (18,636 ) 6,507 (12,129 ) Net other comprehensive income (loss) during period 29,908 (10,514 ) 19,394 Balance December 31, 2014 $ 18,512 $ (23,362 ) $ (4,850 ) Other comprehensive loss before reclassifications (20,439 ) (17,892 ) (38,331 ) Amounts reclassified from accumulated other comprehensive income (loss): Investment securities gain, net (8,133 ) — (8,133 ) Personnel expense — 2,306 2,306 Interest income (555 ) — (555 ) Income tax benefit 11,074 5,873 16,947 Net other comprehensive loss during period (18,053 ) (9,713 ) (27,766 ) Balance December 31, 2015 $ 459 $ (33,075 ) $ (32,616 ) Other comprehensive loss before reclassifications (17,900 ) (6,141 ) (24,041 ) Amounts reclassified from accumulated other comprehensive loss: Investment securities gain, net (9,316 ) — (9,316 ) Personnel expense — 3,801 3,801 Interest income (5,887 ) — (5,887 ) Income tax benefit 12,565 815 13,380 Net other comprehensive loss during period (20,538 ) (1,525 ) (22,063 ) Balance December 31, 2016 $ (20,079 ) $ (34,600 ) $ (54,679 )

Acquisition (Details)

Acquisition (Details) $ in Thousands	Feb. 17, 2015USD ($)	Mar. 31, 2016USD ($)acquisition	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)
Business Acquisition [Line Items]
Goodwill acquired during period		$ 3,000
Number of Acquisitions | acquisition		2
Ahmann and Martin Company
Business Acquisition [Line Items]
Common stock and cash issued in acquisition	$ 48,000
Maximum contingent consideration	$ 8,000
Goodwill acquired during period				$ 40,000
Other Intangibles
Business Acquisition [Line Items]
Additions to finite-lived intangible assets		$ 1,000	$ 1,012	$ 12,115	$ 0

Fair Value Measurements, Assets

Fair Value Measurements, Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Assets, Fair Value Disclosure [Abstract]
Investment securities available for sale	$ 4,680,226	$ 4,967,414
Trading assets	52,398	32,192
Liabilities, Fair Value Disclosure [Abstract]
Trading liabilities	51,103	33,430
Fair Value, Inputs, Level 1
Assets, Fair Value Disclosure [Abstract]
Investment securities available for sale	2,602	2,566
Fair Value, Inputs, Level 2
Assets, Fair Value Disclosure [Abstract]
Investment securities available for sale	4,677,424	4,964,648
Trading assets	54,974	34,907
Liabilities, Fair Value Disclosure [Abstract]
Trading liabilities	53,679	36,145
Fair Value, Inputs, Level 3
Assets, Fair Value Disclosure [Abstract]
Investment securities available for sale	200	200
Trading assets	3,114	1,361
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 | U. S. Treasury securities
Assets, Fair Value Disclosure [Abstract]
Investment securities available for sale	1,000	997
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 | Other securities (debt and equity)
Assets, Fair Value Disclosure [Abstract]
Investment securities available for sale	1,602	1,569
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 | Total investment securities available for sale
Assets, Fair Value Disclosure [Abstract]
Investment securities available for sale	2,602	2,566
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 | FNMA / FHLMC
Assets, Fair Value Disclosure [Abstract]
Investment securities available for sale	639,930	1,414,626
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 | GNMA
Assets, Fair Value Disclosure [Abstract]
Investment securities available for sale	2,004,475	1,590,003
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 | Private-label
Assets, Fair Value Disclosure [Abstract]
Investment securities available for sale	1,121	1,709
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 | GNMA commercial mortgage-related securities
Assets, Fair Value Disclosure [Abstract]
Investment securities available for sale	2,028,898	1,955,310
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 | Other securities (debt and equity)
Assets, Fair Value Disclosure [Abstract]
Investment securities available for sale	3,000	3,000
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 | Total investment securities available for sale
Assets, Fair Value Disclosure [Abstract]
Investment securities available for sale	4,677,424	4,964,648
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 | Interest rate-related instruments
Assets, Fair Value Disclosure [Abstract]
Trading assets	33,671	29,391
Liabilities, Fair Value Disclosure [Abstract]
Trading liabilities	33,188	30,886
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 | Foreign currency exchange forwards
Assets, Fair Value Disclosure [Abstract]
Trading assets	2,002	1,532
Liabilities, Fair Value Disclosure [Abstract]
Trading liabilities	1,943	1,398
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 | Commodity contracts
Assets, Fair Value Disclosure [Abstract]
Trading assets	16,725	1,269
Liabilities, Fair Value Disclosure [Abstract]
Trading liabilities	15,972	1,146
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 | Purchased options (time deposit)
Assets, Fair Value Disclosure [Abstract]
Trading assets	2,576	2,715
Liabilities, Fair Value Disclosure [Abstract]
Trading liabilities	2,576	2,715
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 | Other securities (debt and equity)
Assets, Fair Value Disclosure [Abstract]
Investment securities available for sale	200	200
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 | Total investment securities available for sale
Assets, Fair Value Disclosure [Abstract]
Investment securities available for sale	200	200
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 | Interest rate lock commitments to originate residential mortgage loans held for sale
Assets, Fair Value Disclosure [Abstract]
Trading assets	206	958
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 | Forward commitments to sell residential mortgage loans
Assets, Fair Value Disclosure [Abstract]
Trading assets	$ 2,908	$ 403

Investment Securities, AFS and

Investment Securities, AFS and HTM Securities Amortized Costs and Fair Values (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Investment securities available for sale:
Amortized Cost	$ 4,724,895	$ 4,984,867
Gross Unrealized Gains	19,132	35,684
Gross Unrealized Losses	(63,801)	(53,137)
Fair Value	4,680,226	4,967,414
Investment securities held to maturity:
Amortized Cost	1,273,536	1,168,230
Gross Unrealized Gains	4,523	17,505
Gross Unrealized Losses	(13,385)	(1,293)
Fair Value	1,264,674	1,184,442
U. S. Treasury securities
Investment securities available for sale:
Amortized Cost	1,000	999
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	(2)
Fair Value	1,000	997
Municipal securities
Investment securities held to maturity:
Amortized Cost	1,145,843	1,043,767
Gross Unrealized Gains	3,868	16,803
Gross Unrealized Losses	(12,036)	(339)
Fair Value	1,137,675	1,060,231
Private-label
Investment securities available for sale:
Amortized Cost	1,134	1,722
Gross Unrealized Gains	1	1
Gross Unrealized Losses	(14)	(14)
Fair Value	1,121	1,709
Investment securities held to maturity:
Amortized Cost	0
Fair Value	0
GNMA commercial mortgage-related securities
Investment securities available for sale:
Amortized Cost	2,064,508	1,982,477
Gross Unrealized Gains	356	1,334
Gross Unrealized Losses	(35,966)	(28,501)
Fair Value	2,028,898	1,955,310
Investment securities held to maturity:
Amortized Cost	0
Fair Value	0
Other securities (debt and equity)
Investment securities available for sale:
Amortized Cost	4,718	4,718
Gross Unrealized Gains	105	51
Gross Unrealized Losses	(21)	0
Fair Value	4,802	4,769
FNMA / FHLMC | Residential Related Securities
Investment securities available for sale:
Amortized Cost	625,234	1,388,995
Gross Unrealized Gains	17,298	33,791
Gross Unrealized Losses	(2,602)	(8,160)
Fair Value	639,930	1,414,626
Investment securities held to maturity:
Amortized Cost	37,697	41,469
Gross Unrealized Gains	439	513
Gross Unrealized Losses	(693)	(645)
Fair Value	37,443	41,337
GNMA | Residential Related Securities
Investment securities available for sale:
Amortized Cost	2,028,301	1,605,956
Gross Unrealized Gains	1,372	507
Gross Unrealized Losses	(25,198)	(16,460)
Fair Value	2,004,475	1,590,003
Investment securities held to maturity:
Amortized Cost	89,996	82,994
Gross Unrealized Gains	216	189
Gross Unrealized Losses	(656)	(309)
Fair Value	$ 89,556	$ 82,874

Summary of Significant Accoun54

Summary of Significant Accounting Policies (Details)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Core Deposit Intangibles
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life	10 years
Other Intangibles
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life	12 years	12 years

Fair Value Measurements, Asse55

Fair Value Measurements, Assets and Liabilities Measured at Fair Value Using Significant Unobservable Inputs (Level 3) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Investment Securities Available for Sale
Assets and Liabilities Measured at Fair Value Using Significant Unobservable Inputs (Level 3)
Beginning Balance	$ 200	$ 200
Mortgage derivative gain (loss)	0	0
Ending Balance	200	200
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Mortgage derivative gain (loss)	0	0
Derivative Financial Instruments
Assets and Liabilities Measured at Fair Value Using Significant Unobservable Inputs (Level 3)
Mortgage derivative gain (loss)	1,753	1,849
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Beginning Balance	1,361	(488)
Mortgage derivative gain (loss)	1,753	1,849
Ending Balance	$ 3,114	$ 1,361

Investment Securities, AFS an56

Investment Securities, AFS and HTM Contractual Maturities (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Amortized Cost
Due in one year or less	$ 4,500
Due after one year through five years	1,200
Due after five years through ten years	0
Due after ten years	0
Total debt securities	5,700
Fair Value
Due in one year or less	4,479
Due after one year through five years	1,200
Due after five years through ten years	0
Due after ten years	0
Total debt securities	5,679
Investment securities available for sale, amortized cost	4,724,895	$ 4,984,867
Investment securities available for sale, at fair value	$ 4,680,226	4,967,414
Ratio of Fair Value to Amortized Cost	99.10%
Amortized Cost
Due in one year or less	$ 38,791
Due after one year through five years	257,652
Due after five years through ten years	229,063
Due after ten years	620,337
Held-to-maturity Debt Securities, Amortized Cost Basis	1,145,843
Amortized Cost	1,273,536	1,168,230
Fair Value
Due in one year or less	28,517
Due after one year through five years	264,427
Due after five years through ten years	229,364
Due after ten years	615,367
Held-to-maturity Securities, Debt Securities	1,137,675
Total debt securities	$ 1,264,674	1,184,442
Ratio of Fair Value to Amortized Cost	99.30%
Private-label
Fair Value
Investment securities available for sale, amortized cost	$ 1,134	1,722
Investment securities available for sale, at fair value	1,121	1,709
Amortized Cost
Amortized Cost	0
Fair Value
Total debt securities	0
GNMA commercial mortgage-related securities
Fair Value
Investment securities available for sale, amortized cost	2,064,508	1,982,477
Investment securities available for sale, at fair value	2,028,898	1,955,310
Amortized Cost
Amortized Cost	0
Fair Value
Total debt securities	0
Equity securities
Fair Value
Investment securities available for sale, amortized cost	18
Investment securities available for sale, at fair value	123
Amortized Cost
Amortized Cost	0
Fair Value
Total debt securities	0
FNMA / FHLMC | Residential Related Securities
Fair Value
Investment securities available for sale, amortized cost	625,234	1,388,995
Investment securities available for sale, at fair value	639,930	1,414,626
Amortized Cost
Amortized Cost	37,697	41,469
Fair Value
Total debt securities	37,443	41,337
GNMA | Residential Related Securities
Fair Value
Investment securities available for sale, amortized cost	2,028,301	1,605,956
Investment securities available for sale, at fair value	2,004,475	1,590,003
Amortized Cost
Amortized Cost	89,996	82,994
Fair Value
Total debt securities	$ 89,556	$ 82,874

Summary of Significant Accoun57

Summary of Significant Accounting Policies New Accounting Pronouncements Adopted (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Long-term Debt
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification		$ (3)
Other assets
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification		$ (3)
Reduction in Taxes
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification	$ 1

Fair Value Measurements, Asse58

Fair Value Measurements, Assets and Liabilities Measured at Fair Value on a Nonrecurring Basis (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Assets and Liabilities Measured at Fair Value on a Non-recurring Basis
Mortgage servicing rights	$ 61,476	$ 61,341	$ 60,145
Mortgage Servicing Rights (MSR) Impairment (Recovery)	(200)	(425)	$ 321
Fair Value, Measurements, Nonrecurring | Fair Value, Inputs, Level 2
Assets and Liabilities Measured at Fair Value on a Non-recurring Basis
Commercial loans held for sale	12,474
Provision for credit losses	(559)
Mortgage loans held for sale	108,010	124,915
market valuation adjustment, loans held for sale	(3,760)	(155)
Other real estate owned	9,752	10,988
Foreclosure / OREO expense, net	(1,091)	(2,653)
Fair Value, Measurements, Nonrecurring | Fair Value, Inputs, Level 3
Assets and Liabilities Measured at Fair Value on a Non-recurring Basis
Impaired loans	79,270	41,891
Provision for Credit Losses, Impaired Loans	(75,194)	(7,796)
Mortgage servicing rights	73,149	70,686
Mortgage Servicing Rights (MSR) Impairment (Recovery)	$ 200	$ 425

Investment Securities, Gains, L

Investment Securities, Gains, Losses, and Proceeds (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Available-for-sale Securities, Gross Realized Gain (Loss) [Abstract]
Gross gains	$ 9,518	$ 12,270	$ 1,184
Gross losses	(202)	(4,137)	(690)
Total investment securities gains, net	9,316	8,133	494
Sales of available for sale securities	$ 549,555	$ 1,601,947	$ 102,011

Fair Value Measurements, Fair V

Fair Value Measurements, Fair Value of Financial Instruments (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Commitment on standby letters of credit	$ 260,000	$ 297,000
Financial assets
Cash and due from banks	446,558	374,921
Interest-bearing deposits in other financial institutions	149,175	79,764
Federal funds sold and securities purchased under agreements to resell	46,500	19,000
Investment securities held to maturity	1,273,536	1,168,230
Investment securities held to maturity, fair value	1,264,674	1,184,442
Investment securities available for sale	4,680,226	4,967,414
FHLB and Federal Reserve Bank stocks	140,001	147,240
Loans held for sale	120,484	124,915
Loans, net	19,776,381	18,440,079
Derivatives (trading and other assets)	52,398	32,192
Financial liabilities
Short-term funding	1,092,035	834,416
Long-term funding	2,761,795	2,676,164
Derivatives (trading and other liabilities)	51,103	33,430
Fair Value, Inputs, Level 1
Financial assets
Cash and due from banks	446,558	374,921
Cash and due from banks, Fair Value	446,558	374,921
Interest-bearing deposits in other financial institutions	149,175	79,764
Interest-bearing deposits in other financial institutions, fair value	149,175	79,764
Federal funds sold and securities purchased under agreements to resell	46,500	19,000
Federal funds sold and securities purchased under agreements to resell, fair value	46,500	19,000
Investment securities available for sale	2,602	2,566
Investment securities available for sale, at fair value	2,602	2,566
Fair Value, Inputs, Level 2
Financial assets
Investment securities held to maturity	1,273,536	1,168,230
Investment securities held to maturity, fair value	1,264,674	1,184,442
Investment securities available for sale	4,677,424	4,964,648
Investment securities available for sale, at fair value	4,677,424	4,964,648
FHLB and Federal Reserve Bank stocks	140,001	147,240
FHLB and Federal Reserve Bank stocks, fair value	140,001	147,240
Loans held for sale	120,484	124,915
Loans held for sale, fair value	120,484	124,915
Bank owned life insurance	585,290	583,019
Bank owned life insurance, fair value	585,290	583,019
Derivatives (trading and other assets)	54,974	34,907
Derivatives (trading and other assets), fair value	54,974	34,907
Financial liabilities
Brokered CDs and other time deposits	1,606,127	1,562,802
Brokered CDs and other time deposits, fair value	1,606,127	1,564,464
Short-term funding	1,092,035	834,416
Short-term funding, fair value	1,092,035	834,416
Long-term funding	2,761,795	2,676,164
Long-term funding, fair value	2,791,841	2,728,112
Standby letters of credit	2,566	2,954
Standby letters of credit, fair value	2,566	2,954
Derivatives (trading and other liabilities)	53,679	36,145
Derivatives (trading and other liabilities), fair value	53,679	36,145
Fair Value, Inputs, Level 3
Financial assets
Investment securities available for sale	200	200
Investment securities available for sale, at fair value	200	200
Loans, net	19,776,381	18,440,079
Loans, net, fair value	19,680,317	18,389,832
Derivatives (trading and other assets)	3,114	1,361
Derivatives (trading and other assets), fair value	3,114	1,361
Financial liabilities
Noninterest-bearing demand, savings, interest-bearing demand, and money market accounts	20,282,321	19,444,863
Noninterest-bearing demand, savings, interest-bearing demand, and money market accounts, fair value	$ 20,282,321	$ 19,444,863

Investment Securities, AFS an61

Investment Securities, AFS and HTM Securities Gross Unrealized Losses (Details) $ in Thousands	Dec. 31, 2016USD ($)security	Dec. 31, 2015USD ($)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	$ (44,266)	$ (27,621)
Unrealized losses on available for sale securities, 12 months or more	(19,535)	(25,516)
Total unrealized losses on available for sale securities	(63,801)	(53,137)
Fair value of unrealized losses on available for sale securities, less than 12 months	3,397,143	2,789,260
Fair value of unrealized losses on available for sale securities, 12 months or more	430,377	787,969
Total fair value of unrealized losses on available for sale securities	$ 3,827,520	$ 3,577,229
Number of available for sale securities in a continuous unrealized loss position less than twelve months | security	145	105
Number of available for sale securities in a continuous unrealized loss position for twelve months or more | security	22	38
Held-to-maturity Securities Continuous Unrealized Loss Position [Abstract]
Unrealized losses on held to maturity securities, less than 12 months	$ (13,034)	$ (524)
Unrealized losses on held to maturity securities, 12 months or more	(351)	(769)
Total unrealized losses on held to maturity securities	(13,385)	(1,293)
Fair value of unrealized losses on held to maturity securities, less than 12 months	$ 496,296	$ 81,390
Held-to-maturity, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions, 12 Months or Longer | security	5	30
Fair value of unrealized losses on held to maturity securities, 12 months or more	$ 7,783	$ 27,157
Total fair value of unrealized losses on held to maturity securities	$ 504,079	$ 108,547
Held-to-maturity, Securities In Unrealized Loss Positions Qualitative Disclosure Number Of Positions, less than 12 Months | security	753	84
U. S. 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		997
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		$ 997
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
Municipal securities
Held-to-maturity Securities Continuous Unrealized Loss Position [Abstract]
Unrealized losses on held to maturity securities, less than 12 months	$ (11,937)	$ (146)
Unrealized losses on held to maturity securities, 12 months or more	(99)	(193)
Total unrealized losses on held to maturity securities	(12,036)	(339)
Fair value of unrealized losses on held to maturity securities, less than 12 months	414,186	23,137
Fair value of unrealized losses on held to maturity securities, 12 months or more	1,752	9,254
Total fair value of unrealized losses on held to maturity securities	$ 415,938	$ 32,391
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	700	53
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	4	24
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	$ (1)
Unrealized losses on available for sale securities, 12 months or more	(14)	(13)
Total unrealized losses on available for sale securities	(14)	(14)
Fair value of unrealized losses on available for sale securities, less than 12 months	0	83
Fair value of unrealized losses on available for sale securities, 12 months or more	1,119	1,565
Total fair value of unrealized losses on available for sale securities	$ 1,119	$ 1,648
Number of available for sale securities in a continuous unrealized loss position less than twelve months | security	0	1
Number of available for sale securities in a continuous unrealized loss position for twelve months or more | security	1	3
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	$ (16,445)	$ (9,610)
Unrealized losses on available for sale securities, 12 months or more	(19,521)	(18,891)
Total unrealized losses on available for sale securities	(35,966)	(28,501)
Fair value of unrealized losses on available for sale securities, less than 12 months	1,427,889	1,132,844
Fair value of unrealized losses on available for sale securities, 12 months or more	429,258	448,218
Total fair value of unrealized losses on available for sale securities	$ 1,857,147	$ 1,581,062
Number of available for sale securities in a continuous unrealized loss position less than twelve months | security	74	40
Number of available for sale securities in a continuous unrealized loss position for twelve months or more | security	21	21
Other securities (debt and equity)
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	$ (21)
Unrealized losses on available for sale securities, 12 months or more	0
Total unrealized losses on available for sale securities	(21)
Fair value of unrealized losses on available for sale securities, less than 12 months	1,479
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	$ 1,479
Number of available for sale securities in a continuous unrealized loss position less than twelve months | security	3
Number of available for sale securities in a continuous unrealized loss position for twelve months or more | security	0
FNMA / 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	$ (2,602)	$ (1,548)
Unrealized losses on available for sale securities, 12 months or more	0	(6,612)
Total unrealized losses on available for sale securities	(2,602)	(8,160)
Fair value of unrealized losses on available for sale securities, less than 12 months	244,252	220,852
Fair value of unrealized losses on available for sale securities, 12 months or more	0	338,186
Total fair value of unrealized losses on available for sale securities	$ 244,252	$ 559,038
Number of available for sale securities in a continuous unrealized loss position less than twelve months | security	14	17
Number of available for sale securities in a continuous unrealized loss position for twelve months or more | security	0	14
Held-to-maturity Securities Continuous Unrealized Loss Position [Abstract]
Unrealized losses on held to maturity securities, less than 12 months	$ (441)	$ (177)
Unrealized losses on held to maturity securities, 12 months or more	(252)	(468)
Total unrealized losses on held to maturity securities	(693)	(645)
Fair value of unrealized losses on held to maturity securities, less than 12 months	17,477	12,754
Fair value of unrealized losses on held to maturity securities, 12 months or more	6,031	11,106
Total fair value of unrealized losses on held to maturity securities	$ 23,508	$ 23,860
FNMA / 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	14	10
FNMA / 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	3
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	$ (25,198)	$ (16,460)
Unrealized losses on available for sale securities, 12 months or more	0	0
Total unrealized losses on available for sale securities	(25,198)	(16,460)
Fair value of unrealized losses on available for sale securities, less than 12 months	1,723,523	1,434,484
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	$ 1,723,523	$ 1,434,484
Number of available for sale securities in a continuous unrealized loss position less than twelve months | security	54	46
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	$ (656)	$ (201)
Unrealized losses on held to maturity securities, 12 months or more	0	(108)
Total unrealized losses on held to maturity securities	(656)	(309)
Fair value of unrealized losses on held to maturity securities, less than 12 months	64,633	45,499
Fair value of unrealized losses on held to maturity securities, 12 months or more	0	6,797
Total fair value of unrealized losses on held to maturity securities	$ 64,633	$ 52,296
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	39	21
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	0	3

Fair Value Measurements (Detail

Fair Value Measurements (Details Textuals)	12 Months Ended
	Dec. 31, 2016
Fair Value of Assets and Liabilities [Line Items]
Closing Ratio	90.00%
Weighted average discount rate	9.60%
Weighted average constant prepayment rate	10.80%
Maximum
Fair Value of Assets and Liabilities [Line Items]
Weighted average discount rate	20.00%
Minimum
Fair Value of Assets and Liabilities [Line Items]
Weighted average discount rate	20.00%

Investment Securities (Details

Investment Securities (Details Textual) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Investment Securities (Textuals) [Abstract]
Sales of available for sale securities	$ 549,555	$ 1,601,947	$ 102,011
Marketable Securities, Gain (Loss)	9,316	8,133	$ 494
Securities pledged as collateral	1,800,000	3,200,000
Federal Home Loan Bank Stock	65,000	74,000
Federal Reserve Bank Stock	$ 75,000	$ 73,000

Loans, Loan Composition (Detail

Loans, Loan Composition (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Loans and Leases Receivable Disclosure [Line Items]
Total loans	$ 20,054,716	$ 18,714,343
Commercial and industrial
Loans and Leases Receivable Disclosure [Line Items]
Total loans	6,489,014	6,190,683
Commercial real estate — owner occupied
Loans and Leases Receivable Disclosure [Line Items]
Total loans	897,724	918,212
Commercial and business lending
Loans and Leases Receivable Disclosure [Line Items]
Total loans	7,386,738	7,108,895
Commercial real estate — investor
Loans and Leases Receivable Disclosure [Line Items]
Total loans	3,574,732	3,234,266
Real estate construction
Loans and Leases Receivable Disclosure [Line Items]
Total loans	1,432,497	1,162,145
Commercial real estate lending
Loans and Leases Receivable Disclosure [Line Items]
Total loans	5,007,229	4,396,411
Total commercial
Loans and Leases Receivable Disclosure [Line Items]
Total loans	12,393,967	11,505,306
Residential mortgage
Loans and Leases Receivable Disclosure [Line Items]
Total loans	6,332,327	5,783,267
Home equity
Loans and Leases Receivable Disclosure [Line Items]
Total loans	934,443	1,005,802
Other consumer
Loans and Leases Receivable Disclosure [Line Items]
Total loans	393,979	419,968
Total consumer
Loans and Leases Receivable Disclosure [Line Items]
Total loans	$ 7,660,749	$ 7,209,037

Loans, Related Party Loan Rollf

Loans, Related Party Loan Rollforward (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2016USD ($)
Loans and Leases Receivable, Related Parties [Roll Forward]
Balance at beginning of year	$ 36,597
New loans	10,677
Repayments	(11,089)
Changes due to status of executive officers and directors	(8,596)
Balance at end of year	$ 27,589

Loans, Loans by Credit Quality

Loans, Loans by Credit Quality Indicator (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	$ 20,054,716	$ 18,714,343
Pass
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	19,251,353	17,804,216
Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	176,918	430,152
Potential Problem
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	351,142	301,717
Nonaccrual
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	275,303	178,258
Commercial and industrial
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	6,489,014	6,190,683
Commercial and industrial | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	5,937,119	5,522,809
Commercial and industrial | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	141,328	341,169
Commercial and industrial | Potential Problem
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	227,196	233,130
Commercial and industrial | Nonaccrual
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	183,371	93,575
Commercial real estate — owner occupied
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	897,724	918,212
Commercial real estate — owner occupied | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	805,871	835,572
Commercial real estate — owner occupied | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	17,785	38,885
Commercial real estate — owner occupied | Potential Problem
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	64,524	35,706
Commercial real estate — owner occupied | Nonaccrual
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	9,544	8,049
Commercial and business lending
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	7,386,738	7,108,895
Commercial and business lending | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	6,742,990	6,358,381
Commercial and business lending | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	159,113	380,054
Commercial and business lending | Potential Problem
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	291,720	268,836
Commercial and business lending | Nonaccrual
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	192,915	101,624
Commercial real estate — investor
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	3,574,732	3,234,266
Commercial real estate — investor | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	3,491,217	3,153,703
Commercial real estate — investor | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	14,236	45,976
Commercial real estate — investor | Potential Problem
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	51,228	25,944
Commercial real estate — investor | Nonaccrual
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	18,051	8,643
Real estate construction
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	1,432,497	1,162,145
Real estate construction | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	1,429,083	1,157,034
Real estate construction | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	105	252
Real estate construction | Potential Problem
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	2,465	3,919
Real estate construction | Nonaccrual
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	844	940
Commercial real estate lending
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	5,007,229	4,396,411
Commercial real estate lending | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	4,920,300	4,310,737
Commercial real estate lending | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	14,341	46,228
Commercial real estate lending | Potential Problem
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	53,693	29,863
Commercial real estate lending | Nonaccrual
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	18,895	9,583
Total commercial
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	12,393,967	11,505,306
Total commercial | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	11,663,290	10,669,118
Total commercial | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	173,454	426,282
Total commercial | Potential Problem
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	345,413	298,699
Total commercial | Nonaccrual
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	211,810	111,207
Residential mortgage
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	6,332,327	5,783,267
Residential mortgage | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	6,275,162	5,727,437
Residential mortgage | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	1,314	1,552
Residential mortgage | Potential Problem
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	5,615	2,796
Residential mortgage | Nonaccrual
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	50,236	51,482
Home equity
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	934,443	1,005,802
Home equity | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	919,740	988,574
Home equity | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	1,588	1,762
Home equity | Potential Problem
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	114	222
Home equity | Nonaccrual
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	13,001	15,244
Other consumer
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	393,979	419,968
Other consumer | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	393,161	419,087
Other consumer | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	562	556
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	256	325
Total consumer
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	7,660,749	7,209,037
Total consumer | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	7,588,063	7,135,098
Total consumer | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	3,464	3,870
Total consumer | Potential Problem
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	5,729	3,018
Total consumer | Nonaccrual
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net of Deferred Income	$ 63,493	$ 67,051

Loans, Loans by Past Due Status

Loans, Loans by Past Due Status (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Summarized details of Loans
Current	$ 19,756,523	$ 18,510,978
Financing Receivable, Recorded Investment, Nonaccrual Status	275,303	178,258
Total loans	20,054,716	18,714,343
Nonaccrual Loans, Current Portion	$ 224,000	$ 124,000
Percent of current nonaccrual loans	81.00%	69.00%
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing	$ 2,000	$ 2,000
30-59 Days Past Due
Summarized details of Loans
Total Past Due	16,662	20,181
60-89 Days Past Due
Summarized details of Loans
Total Past Due	4,615	3,278
90 Days or More Past Due
Summarized details of Loans
Total Past Due	1,613	1,648
Commercial and industrial
Summarized details of Loans
Current	6,303,994	6,095,848
Financing Receivable, Recorded Investment, Nonaccrual Status	183,371	93,575
Total loans	6,489,014	6,190,683
Commercial and industrial | 30-59 Days Past Due
Summarized details of Loans
Total Past Due	965	602
Commercial and industrial | 60-89 Days Past Due
Summarized details of Loans
Total Past Due	448	409
Commercial and industrial | 90 Days or More Past Due
Summarized details of Loans
Total Past Due	236	249
Commercial real estate — owner occupied
Summarized details of Loans
Current	886,796	903,021
Financing Receivable, Recorded Investment, Nonaccrual Status	9,544	8,049
Total loans	897,724	918,212
Commercial real estate — owner occupied | 30-59 Days Past Due
Summarized details of Loans
Total Past Due	968	7,142
Commercial real estate — owner occupied | 60-89 Days Past Due
Summarized details of Loans
Total Past Due	416	0
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	7,190,790	6,998,869
Financing Receivable, Recorded Investment, Nonaccrual Status	192,915	101,624
Total loans	7,386,738	7,108,895
Commercial and business lending | 30-59 Days Past Due
Summarized details of Loans
Total Past Due	1,933	7,744
Commercial and business lending | 60-89 Days Past Due
Summarized details of Loans
Total Past Due	864	409
Commercial and business lending | 90 Days or More Past Due
Summarized details of Loans
Total Past Due	236	249
Commercial real estate — investor
Summarized details of Loans
Current	3,555,750	3,225,332
Financing Receivable, Recorded Investment, Nonaccrual Status	18,051	8,643
Total loans	3,574,732	3,234,266
Commercial real estate — investor | 30-59 Days Past Due
Summarized details of Loans
Total Past Due	431	291
Commercial real estate — investor | 60-89 Days Past Due
Summarized details of Loans
Total Past Due	500	0
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	1,431,284	1,160,909
Financing Receivable, Recorded Investment, Nonaccrual Status	844	940
Total loans	1,432,497	1,162,145
Real estate construction | 30-59 Days Past Due
Summarized details of Loans
Total Past Due	264	270
Real estate construction | 60-89 Days Past Due
Summarized details of Loans
Total Past Due	105	26
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	4,987,034	4,386,241
Financing Receivable, Recorded Investment, Nonaccrual Status	18,895	9,583
Total loans	5,007,229	4,396,411
Commercial real estate lending | 30-59 Days Past Due
Summarized details of Loans
Total Past Due	695	561
Commercial real estate lending | 60-89 Days Past Due
Summarized details of Loans
Total Past Due	605	26
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	12,177,824	11,385,110
Financing Receivable, Recorded Investment, Nonaccrual Status	211,810	111,207
Total loans	12,393,967	11,505,306
Total commercial | 30-59 Days Past Due
Summarized details of Loans
Total Past Due	2,628	8,305
Total commercial | 60-89 Days Past Due
Summarized details of Loans
Total Past Due	1,469	435
Total commercial | 90 Days or More Past Due
Summarized details of Loans
Total Past Due	236	249
Residential mortgage
Summarized details of Loans
Current	6,273,949	5,726,855
Financing Receivable, Recorded Investment, Nonaccrual Status	50,236	51,482
Total loans	6,332,327	5,783,267
Residential mortgage | 30-59 Days Past Due
Summarized details of Loans
Total Past Due	7,298	4,491
Residential mortgage | 60-89 Days Past Due
Summarized details of Loans
Total Past Due	844	439
Residential mortgage | 90 Days or More Past Due
Summarized details of Loans
Total Past Due	0	0
Home equity
Summarized details of Loans
Current	915,593	982,639
Financing Receivable, Recorded Investment, Nonaccrual Status	13,001	15,244
Total loans	934,443	1,005,802
Home equity | 30-59 Days Past Due
Summarized details of Loans
Total Past Due	4,265	6,190
Home equity | 60-89 Days Past Due
Summarized details of Loans
Total Past Due	1,584	1,729
Home equity | 90 Days or More Past Due
Summarized details of Loans
Total Past Due	0	0
Other consumer
Summarized details of Loans
Current	389,157	416,374
Financing Receivable, Recorded Investment, Nonaccrual Status	256	325
Total loans	393,979	419,968
Other consumer | 30-59 Days Past Due
Summarized details of Loans
Total Past Due	2,471	1,195
Other consumer | 60-89 Days Past Due
Summarized details of Loans
Total Past Due	718	675
Other consumer | 90 Days or More Past Due
Summarized details of Loans
Total Past Due	1,377	1,399
Total consumer
Summarized details of Loans
Current	7,578,699	7,125,868
Financing Receivable, Recorded Investment, Nonaccrual Status	63,493	67,051
Total loans	7,660,749	7,209,037
Total consumer | 30-59 Days Past Due
Summarized details of Loans
Total Past Due	14,034	11,876
Total consumer | 60-89 Days Past Due
Summarized details of Loans
Total Past Due	3,146	2,843
Total consumer | 90 Days or More Past Due
Summarized details of Loans
Total Past Due	$ 1,377	$ 1,399

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	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	$ 355,160	$ 265,621
Unpaid Principal Balance	394,588	284,433
Related Allowance	46,483	33,669
Average Recorded Investment	378,277	273,011
Interest Income Recognized	$ 10,228	$ 8,716
Net Recorded Investment of the Impaired Loans	78.00%	82.00%
Loans with a related allowance
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	$ 221,012	$ 186,275
Unpaid Principal Balance	236,876	197,109
Related Allowance	46,483	33,669
Average Recorded Investment	237,729	178,871
Interest Income Recognized	8,383	6,798
Loans with no related allowance
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	134,148	79,346
Unpaid Principal Balance	157,712	87,324
Related Allowance	0	0
Average Recorded Investment	140,548	94,140
Interest Income Recognized	1,845	1,918
Commercial and industrial
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	215,255	122,868
Unpaid Principal Balance	242,676	131,668
Related Allowance	21,617	8,162
Average Recorded Investment	229,191	126,406
Interest Income Recognized	4,031	2,512
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	101,770	57,785
Unpaid Principal Balance	107,813	59,409
Related Allowance	21,617	8,162
Average Recorded Investment	111,211	46,833
Interest Income Recognized	2,512	855
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	113,485	65,083
Unpaid Principal Balance	134,863	72,259
Related Allowance	0	0
Average Recorded Investment	117,980	79,573
Interest Income Recognized	1,519	1,657
Commercial real estate — owner occupied
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	15,034	15,926
Unpaid Principal Balance	17,907	16,452
Related Allowance	295	448
Average Recorded Investment	15,870	16,621
Interest Income Recognized	412	427
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	6,595	9,705
Unpaid Principal Balance	8,641	9,804
Related Allowance	295	448
Average Recorded Investment	7,111	10,087
Interest Income Recognized	274	412
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	8,439	6,221
Unpaid Principal Balance	9,266	6,648
Related Allowance	0	0
Average Recorded Investment	8,759	6,534
Interest Income Recognized	138	15
Commercial and business lending
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	230,289	138,794
Unpaid Principal Balance	260,583	148,120
Related Allowance	21,912	8,610
Average Recorded Investment	245,061	143,027
Interest Income Recognized	4,443	2,939
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	108,365	67,490
Unpaid Principal Balance	116,454	69,213
Related Allowance	21,912	8,610
Average Recorded Investment	118,322	56,920
Interest Income Recognized	2,786	1,267
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	121,924	71,304
Unpaid Principal Balance	144,129	78,907
Related Allowance	0	0
Average Recorded Investment	126,739	86,107
Interest Income Recognized	1,657	1,672
Commercial real estate — investor
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	33,340	30,558
Unpaid Principal Balance	34,155	32,284
Related Allowance	3,541	1,831
Average Recorded Investment	38,234	31,041
Interest Income Recognized	2,124	2,004
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	27,196	27,822
Unpaid Principal Balance	27,677	29,444
Related Allowance	3,541	1,831
Average Recorded Investment	31,142	28,278
Interest Income Recognized	2,124	1,914
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	6,144	2,736
Unpaid Principal Balance	6,478	2,840
Related Allowance	0	0
Average Recorded Investment	7,092	2,763
Interest Income Recognized	0	90
Real estate construction
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	1,203	1,450
Unpaid Principal Balance	1,566	2,154
Related Allowance	441	453
Average Recorded Investment	1,321	1,667
Interest Income Recognized	67	66
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	1,203	1,450
Unpaid Principal Balance	1,566	2,154
Related Allowance	441	453
Average Recorded Investment	1,321	1,667
Interest Income Recognized	67	66
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	0	0
Unpaid Principal Balance	0	0
Related Allowance	0	0
Average Recorded Investment	0	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	34,543	32,008
Unpaid Principal Balance	35,721	34,438
Related Allowance	3,982	2,284
Average Recorded Investment	39,555	32,708
Interest Income Recognized	2,191	2,070
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	28,399	29,272
Unpaid Principal Balance	29,243	31,598
Related Allowance	3,982	2,284
Average Recorded Investment	32,463	29,945
Interest Income Recognized	2,191	1,980
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	6,144	2,736
Unpaid Principal Balance	6,478	2,840
Related Allowance	0	0
Average Recorded Investment	7,092	2,763
Interest Income Recognized	0	90
Total commercial
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	264,832	170,802
Unpaid Principal Balance	296,304	182,558
Related Allowance	25,894	10,894
Average Recorded Investment	284,616	175,735
Interest Income Recognized	6,634	5,009
Total commercial | Loans with a related allowance
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	136,764	96,762
Unpaid Principal Balance	145,697	100,811
Related Allowance	25,894	10,894
Average Recorded Investment	150,785	86,865
Interest Income Recognized	4,977	3,247
Total commercial | Loans with no related allowance
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	128,068	74,040
Unpaid Principal Balance	150,607	81,747
Related Allowance	0	0
Average Recorded Investment	133,831	88,870
Interest Income Recognized	1,657	1,762
Residential mortgage
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	68,336	71,352
Unpaid Principal Balance	74,088	76,117
Related Allowance	11,091	12,462
Average Recorded Investment	70,435	72,909
Interest Income Recognized	2,447	2,500
Residential mortgage | Loans with a related allowance
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	62,362	66,590
Unpaid Principal Balance	67,090	71,084
Related Allowance	11,091	12,462
Average Recorded Investment	63,825	68,183
Interest Income Recognized	2,263	2,374
Residential mortgage | Loans with no related allowance
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	5,974	4,762
Unpaid Principal Balance	6,998	5,033
Related Allowance	0	0
Average Recorded Investment	6,610	4,726
Interest Income Recognized	184	126
Home equity
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	20,757	22,313
Unpaid Principal Balance	22,912	24,533
Related Allowance	9,312	10,118
Average Recorded Investment	21,932	23,168
Interest Income Recognized	1,118	1,177
Home equity | Loans with a related allowance
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	20,651	21,769
Unpaid Principal Balance	22,805	23,989
Related Allowance	9,312	10,118
Average Recorded Investment	21,825	22,624
Interest Income Recognized	1,114	1,147
Home equity | Loans with no related allowance
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	106	544
Unpaid Principal Balance	107	544
Related Allowance	0	0
Average Recorded Investment	107	544
Interest Income Recognized	4	30
Other consumer
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	1,235	1,154
Unpaid Principal Balance	1,284	1,225
Related Allowance	186	195
Average Recorded Investment	1,294	1,199
Interest Income Recognized	29	30
Other consumer | Loans with a related allowance
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	1,235	1,154
Unpaid Principal Balance	1,284	1,225
Related Allowance	186	195
Average Recorded Investment	1,294	1,199
Interest Income Recognized	29	30
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	90,328	94,819
Unpaid Principal Balance	98,284	101,875
Related Allowance	20,589	22,775
Average Recorded Investment	93,661	97,276
Interest Income Recognized	3,594	3,707
Total consumer | Loans with a related allowance
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	84,248	89,513
Unpaid Principal Balance	91,179	96,298
Related Allowance	20,589	22,775
Average Recorded Investment	86,944	92,006
Interest Income Recognized	3,406	3,551
Total consumer | Loans with no related allowance
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	6,080	5,306
Unpaid Principal Balance	7,105	5,577
Related Allowance	0	0
Average Recorded Investment	6,717	5,270
Interest Income Recognized	$ 188	$ 156

Loans, Troubled Debt Restructur

Loans, Troubled Debt Restructurings Performing and Nonaccrual (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Financing Receivable, Modifications [Line Items]
Performing Restructured Loans	$ 79,857	$ 87,363	$ 98,216
Nonaccrual Restructured Loans	29,385	37,684	57,656
Commercial and industrial
Financing Receivable, Modifications [Line Items]
Performing Restructured Loans	31,884	29,293	33,892
Nonaccrual Restructured Loans	1,276	1,714	3,260
Commercial real estate — owner occupied
Financing Receivable, Modifications [Line Items]
Performing Restructured Loans	5,490	7,877	10,454
Nonaccrual Restructured Loans	2,220	2,703	5,656
Commercial real estate — investor
Financing Receivable, Modifications [Line Items]
Performing Restructured Loans	15,289	21,915	23,127
Nonaccrual Restructured Loans	924	3,936	15,216
Real estate construction
Financing Receivable, Modifications [Line Items]
Performing Restructured Loans	359	510	727
Nonaccrual Restructured Loans	150	177	2,438
Residential mortgage
Financing Receivable, Modifications [Line Items]
Performing Restructured Loans	18,100	19,870	20,833
Nonaccrual Restructured Loans	21,906	24,592	26,049
Home equity
Financing Receivable, Modifications [Line Items]
Performing Restructured Loans	7,756	7,069	8,209
Nonaccrual Restructured Loans	2,877	4,522	4,838
Other consumer
Financing Receivable, Modifications [Line Items]
Performing Restructured Loans	979	829	974
Nonaccrual Restructured Loans	$ 32	$ 40	$ 199

Loans, Loans Modified in a Trou

Loans, Loans Modified in a Troubled Debt Restructuring (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2016USD ($)loan	Dec. 31, 2015USD ($)loan	Dec. 31, 2014USD ($)loan
Financing Receivable, Modifications [Line Items]
Number of Loans | loan	131	211	309
Recorded Investment	$ 9,270	$ 41,131	$ 38,870
Unpaid Principal Balance	$ 9,631	$ 42,765	$ 40,660
Commercial and industrial
Financing Receivable, Modifications [Line Items]
Number of Loans | loan	8	12	15
Recorded Investment	$ 1,509	$ 2,219	$ 7,681
Unpaid Principal Balance	$ 1,526	$ 2,900	$ 7,711
Commercial real estate — owner occupied
Financing Receivable, Modifications [Line Items]
Number of Loans | loan	1	5	4
Recorded Investment	$ 116	$ 3,694	$ 1,465
Unpaid Principal Balance	$ 122	$ 3,901	$ 1,625
Commercial real estate — investor
Financing Receivable, Modifications [Line Items]
Number of Loans | loan	0	5	6
Recorded Investment	$ 0	$ 21,573	$ 6,097
Unpaid Principal Balance	$ 0	$ 21,640	$ 6,521
Real estate construction
Financing Receivable, Modifications [Line Items]
Number of Loans | loan	1	4	2
Recorded Investment	$ 65	$ 78	$ 15
Unpaid Principal Balance	$ 91	$ 79	$ 15
Residential mortgage
Financing Receivable, Modifications [Line Items]
Number of Loans | loan	63	97	163
Recorded Investment	$ 5,535	$ 10,464	$ 19,675
Unpaid Principal Balance	$ 5,792	$ 10,996	$ 20,454
Home equity
Financing Receivable, Modifications [Line Items]
Number of Loans | loan	57	88	117
Recorded Investment	$ 2,030	$ 3,103	$ 3,913
Unpaid Principal Balance	$ 2,084	$ 3,249	$ 4,308
Other consumer
Financing Receivable, Modifications [Line Items]
Number of Loans | loan	1	0	2
Recorded Investment	$ 15	$ 0	$ 24
Unpaid Principal Balance	$ 16	$ 0	$ 26

Loans, Troubled Debt Restruct71

Loans, Troubled Debt Restructurings Subsequent Default (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2016USD ($)loan	Dec. 31, 2015USD ($)loan	Dec. 31, 2014USD ($)loan
Financing Receivable, Modifications [Line Items]
Number of Loans | loan	68	91	155
Recorded Investment | $	$ 4,574	$ 8,232	$ 19,065
Commercial and industrial
Financing Receivable, Modifications [Line Items]
Number of Loans | loan	0	2	1
Recorded Investment | $	$ 0	$ 197	$ 52
Commercial real estate — owner occupied
Financing Receivable, Modifications [Line Items]
Number of Loans | loan	0	0	3
Recorded Investment | $	$ 0	$ 0	$ 785
Commercial real estate — investor
Financing Receivable, Modifications [Line Items]
Number of Loans | loan	0	0	13
Recorded Investment | $	$ 0	$ 0	$ 6,200
Real estate construction
Financing Receivable, Modifications [Line Items]
Number of Loans | loan	0	0	1
Recorded Investment | $	$ 0	$ 0	$ 160
Residential mortgage
Financing Receivable, Modifications [Line Items]
Number of Loans | loan	44	61	80
Recorded Investment | $	$ 4,102	$ 6,815	$ 10,032
Home equity
Financing Receivable, Modifications [Line Items]
Number of Loans | loan	23	28	54
Recorded Investment | $	$ 457	$ 1,220	$ 1,802
Other consumer
Financing Receivable, Modifications [Line Items]
Number of Loans | loan	1	0	3
Recorded Investment | $	$ 15	$ 0	$ 34

Loans, Changes in the Allowance

Loans, Changes in the Allowance for Loan Losses by Portfolio Segment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Changes in the allowance for loan losses by portfolio segment
Balance at beginning of year	$ 274,264	$ 266,302
Charge offs	(86,439)	(52,280)
Recoveries	21,510	22,242
Net charge offs	(64,929)	(30,038)
Provision for loan losses	69,000	38,000
Balance at end of period	278,335	274,264
Allowance for loan losses:
Individually evaluated for impairment	24,103	7,963
Collectively evaluated for impairment	254,232	266,301
Balance at end of period	278,335	274,264
Loans:
Individually evaluated for impairment	214,409	111,487
Collectively evaluated for impairment	19,840,307	18,602,856
Total loans	20,054,716	18,714,343
Commercial and industrial
Changes in the allowance for loan losses by portfolio segment
Balance at beginning of year	129,959	117,635
Charge offs	(71,016)	(27,687)
Recoveries	14,543	9,821
Net charge offs	(56,473)	(17,866)
Provision for loan losses	66,640	30,190
Balance at end of period	140,126	129,959
Allowance for loan losses:
Individually evaluated for impairment	20,836	7,522
Collectively evaluated for impairment	119,290	122,437
Balance at end of period	140,126	129,959
Loans:
Individually evaluated for impairment	180,965	91,569
Collectively evaluated for impairment	6,308,049	6,099,114
Total loans	6,489,014	6,190,683
Commercial real estate — owner occupied
Changes in the allowance for loan losses by portfolio segment
Balance at beginning of year	18,680	16,510
Charge offs	(512)	(2,645)
Recoveries	74	921
Net charge offs	(438)	(1,724)
Provision for loan losses	4,208	3,894
Balance at end of period	14,034	18,680
Allowance for loan losses:
Individually evaluated for impairment	0	0
Collectively evaluated for impairment	14,034	18,680
Balance at end of period	14,034	18,680
Loans:
Individually evaluated for impairment	8,439	6,221
Collectively evaluated for impairment	889,285	911,991
Total loans	897,724	918,212
Commercial real estate — investor
Changes in the allowance for loan losses by portfolio segment
Balance at beginning of year	43,018	46,333
Charge offs	(1,504)	(4,645)
Recoveries	1,624	4,157
Net charge offs	120	(488)
Provision for loan losses	2,147	2,827
Balance at end of period	45,285	43,018
Allowance for loan losses:
Individually evaluated for impairment	3,117	229
Collectively evaluated for impairment	42,168	42,789
Balance at end of period	45,285	43,018
Loans:
Individually evaluated for impairment	17,322	5,460
Collectively evaluated for impairment	3,557,410	3,228,806
Total loans	3,574,732	3,234,266
Real estate construction
Changes in the allowance for loan losses by portfolio segment
Balance at beginning of year	25,266	20,999
Charge offs	(558)	(750)
Recoveries	203	2,268
Net charge offs	(355)	1,518
Provision for loan losses	2,021	2,749
Balance at end of period	26,932	25,266
Allowance for loan losses:
Individually evaluated for impairment	0	0
Collectively evaluated for impairment	26,932	25,266
Balance at end of period	26,932	25,266
Loans:
Individually evaluated for impairment	0	0
Collectively evaluated for impairment	1,432,497	1,162,145
Total loans	1,432,497	1,162,145
Residential mortgage
Changes in the allowance for loan losses by portfolio segment
Balance at beginning of year	28,261	31,926
Charge offs	(4,332)	(5,636)
Recoveries	755	1,077
Net charge offs	(3,577)	(4,559)
Provision for loan losses	2,362	894
Balance at end of period	27,046	28,261
Allowance for loan losses:
Individually evaluated for impairment	147	166
Collectively evaluated for impairment	26,899	28,095
Balance at end of period	27,046	28,261
Loans:
Individually evaluated for impairment	7,033	6,956
Collectively evaluated for impairment	6,325,294	5,776,311
Total loans	6,332,327	5,783,267
Home equity
Changes in the allowance for loan losses by portfolio segment
Balance at beginning of year	23,555	26,464
Charge offs	(4,686)	(7,048)
Recoveries	3,491	3,233
Net charge offs	(1,195)	(3,815)
Provision for loan losses	1,996	906
Balance at end of period	20,364	23,555
Allowance for loan losses:
Individually evaluated for impairment	3	46
Collectively evaluated for impairment	20,361	23,509
Balance at end of period	20,364	23,555
Loans:
Individually evaluated for impairment	650	1,281
Collectively evaluated for impairment	933,793	1,004,521
Total loans	934,443	1,005,802
Other consumer
Changes in the allowance for loan losses by portfolio segment
Balance at beginning of year	5,525	6,435
Charge offs	(3,831)	(3,869)
Recoveries	820	765
Net charge offs	(3,011)	(3,104)
Provision for loan losses	2,034	2,194
Balance at end of period	4,548	5,525
Allowance for loan losses:
Individually evaluated for impairment	0	0
Collectively evaluated for impairment	4,548	5,525
Balance at end of period	4,548	5,525
Loans:
Individually evaluated for impairment	0	0
Collectively evaluated for impairment	393,979	419,968
Total loans	$ 393,979	$ 419,968

Loans, Changes in the Allowan73

Loans, Changes in the Allowance for Loan Losses (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Change in the Allowance for Unfunded Commitments
Balance at beginning of period	$ 24,000
Balance at end of period	25,000	$ 24,000
Allowance for Unfunded Commitments:
Change in the Allowance for Unfunded Commitments
Balance at beginning of period	24,400	24,900	$ 21,900
Provision for Other Credit Losses	(1,000)	(500)	(3,000)
Balance at end of period	$ 25,400	$ 24,400	$ 24,900

Loans (Details Textuals)

Loans (Details Textuals) $ in Millions	Dec. 31, 2016USD ($)
Receivables [Abstract]
Loans and Leases Receivable, Impaired, Commitment to Lend	$ 7

Goodwill and Intangible Assets,

Goodwill and Intangible Assets, Summary of Core Deposit and Other Intangibles (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Summary of core deposit intangibles and other intangibles
Amortization of other intangible assets		$ 2,093	$ 3,094	$ 3,747
Core Deposit Intangibles
Summary of core deposit intangibles and other intangibles
Gross carrying amount		4,385	19,545	36,230
Accumulated amortization		(4,273)	(19,152)	(34,433)
Total Estimated Amortization Expense		112	393	1,797
Amortization of other intangible assets		281	1,404	2,868
Other Intangibles
Summary of core deposit intangibles and other intangibles
Gross carrying amount		32,410	31,398	19,283
Accumulated amortization		(17,145)	(15,333)	(13,643)
Total Estimated Amortization Expense		15,265	16,065	5,640
Additions during the period	$ 1,000	1,012	12,115	0
Amortization of other intangible assets		$ 1,812	$ 1,690	$ 879

Goodwill and Intangible Asset76

Goodwill and Intangible Assets, Mortgage Servicing Rights Roll-Forward (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Mortgage servicing rights:
Mortgage servicing rights at beginning of year	$ 62,150	$ 61,379	$ 64,193
Additions	12,262	12,372	8,253
Amortization	(12,327)	(11,601)	(11,067)
Mortgage servicing rights at end of year	62,085	62,150	61,379
Valuation Allowance for Impairment of Recognized Servicing Assets [Roll Forward]
Valuation allowance at beginning of year	(809)	(1,234)	(913)
(Additions) recoveries, net	200	425	(321)
Valuation allowance at end of year	(609)	(809)	(1,234)
Mortgage servicing rights, net	61,476	61,341	60,145
Fair value of mortgage servicing rights	73,149	70,686	66,342
Portfolio of residential mortgage loans serviced for others (“servicing portfolio”)	$ 7,974,742	$ 7,915,224	$ 7,999,294
Mortgage servicing rights, net to servicing portfolio	0.77%	0.77%	0.75%
Mortgage servicing rights expense	$ 12,127	$ 11,176	$ 11,388

Goodwill and Intangible Asset77

Goodwill and Intangible Assets, Estimated Future Amortization Expense (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Core Deposit Intangibles
Estimated future amortization expense
Year ending December 31, 2017	$ 112
Year ending December 31, 2018	0
Year ending December 31, 2019	0
Year ending December 31, 2020	0
Year ending December 31, 2021	0
Beyond 2,021	0
Total Estimated Amortization Expense	112	$ 393	$ 1,797
Other Intangibles
Estimated future amortization expense
Year ending December 31, 2017	1,786
Year ending December 31, 2018	1,756
Year ending December 31, 2019	1,457
Year ending December 31, 2020	1,340
Year ending December 31, 2021	1,316
Beyond 2,021	7,610
Total Estimated Amortization Expense	15,265	$ 16,065	$ 5,640
Mortgage Servicing Rights
Estimated future amortization expense
Year ending December 31, 2017	9,627
Year ending December 31, 2018	8,134
Year ending December 31, 2019	6,878
Year ending December 31, 2020	5,840
Year ending December 31, 2021	4,970
Beyond 2,021	26,636
Total Estimated Amortization Expense	$ 62,085

Goodwill and Intangible Asset78

Goodwill and Intangible Assets (Details Textuals) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2016USD ($)acquisition	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)
Business Acquisition [Line Items]
Goodwill, Impairment Loss		$ 0	$ 0
Goodwill acquired during period	$ 3,000
Goodwill		971,951	$ 968,844
Finite-Lived Core Deposits, Gross		15,000
Number of Acquisitions | acquisition	2
Corporate and Commercial Specialty | Operating Segments
Business Acquisition [Line Items]
Goodwill		$ 428,000
Customer Relationships [Member]
Business Acquisition [Line Items]
Additions to finite-lived intangible assets	$ 1,000

Premises and Equipment, Summary

Premises and Equipment, Summary Composition (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Property, Plant and Equipment, Net, by Type [Abstract]
Cost	$ 641,701
Accumulated Depreciation	311,386
Net Book Value	330,315	$ 267,606
Land
Property, Plant and Equipment, Net, by Type [Abstract]
Cost	57,471
Accumulated Depreciation	0
Net Book Value	57,471	52,104
Land improvements
Property, Plant and Equipment, Net, by Type [Abstract]
Cost	12,572
Accumulated Depreciation	5,929
Net Book Value	$ 6,643	6,661
Land improvements | Maximum
Property, Plant and Equipment, Net, by Type [Abstract]
Estimated Useful Lives	15 years
Land improvements | Minimum
Property, Plant and Equipment, Net, by Type [Abstract]
Estimated Useful Lives	3 years
Buildings
Property, Plant and Equipment, Net, by Type [Abstract]
Cost	$ 332,256
Accumulated Depreciation	130,104
Net Book Value	$ 202,152	141,432
Buildings | Maximum
Property, Plant and Equipment, Net, by Type [Abstract]
Estimated Useful Lives	39 years
Buildings | Minimum
Property, Plant and Equipment, Net, by Type [Abstract]
Estimated Useful Lives	5 years
Computers
Property, Plant and Equipment, Net, by Type [Abstract]
Cost	$ 42,190
Accumulated Depreciation	33,139
Net Book Value	$ 9,051	6,372
Computers | Maximum
Property, Plant and Equipment, Net, by Type [Abstract]
Estimated Useful Lives	5 years
Computers | Minimum
Property, Plant and Equipment, Net, by Type [Abstract]
Estimated Useful Lives	3 years
Furniture, fixtures and other equipment
Property, Plant and Equipment, Net, by Type [Abstract]
Cost	$ 162,253
Accumulated Depreciation	119,704
Net Book Value	$ 42,549	49,794
Furniture, fixtures and other equipment | Maximum
Property, Plant and Equipment, Net, by Type [Abstract]
Estimated Useful Lives	15 years
Furniture, fixtures and other equipment | Minimum
Property, Plant and Equipment, Net, by Type [Abstract]
Estimated Useful Lives	3 years
Leasehold improvements
Property, Plant and Equipment, Net, by Type [Abstract]
Cost	$ 34,959
Accumulated Depreciation	22,510
Net Book Value	$ 12,449	$ 11,243
Leasehold improvements | Maximum
Property, Plant and Equipment, Net, by Type [Abstract]
Estimated Useful Lives	15 years
Leasehold improvements | Minimum
Property, Plant and Equipment, Net, by Type [Abstract]
Estimated Useful Lives	3 years

Premises and Equipment, Minimum

Premises and Equipment, Minimum Annual Rent Under Operating Lease Agreements (Details) $ in Thousands	Dec. 31, 2016USD ($)
Operating Leases, Future Minimum Payments Receivable [Abstract]
2,017	$ 9,711
2,018	9,665
2,019	9,115
2,020	8,133
2,021	7,336
Thereafter	20,940
Total	$ 64,900

Premises and Equipment (Details

Premises and Equipment (Details Textuals) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Property, Plant and Equipment [Line Items]
Depreciation and amortization	$ 32	$ 33	$ 34
Rental expense under leases	8	$ 13	$ 11
Milwaukee Center
Property, Plant and Equipment [Line Items]
Leasing income	$ 4

Deposits, Composition (Details)

Deposits, Composition (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Deposits, by Type [Abstract]
Noninterest-bearing demand deposits	$ 5,392,208	$ 5,562,466
Savings	1,431,494	1,334,420
Interest-bearing demand	4,687,656	3,445,000
Money market	8,770,963	9,102,977
Brokered CDs	52,725	42,443
Other time	1,553,402	1,520,359
Total deposits	$ 21,888,448	$ 21,007,665

Deposits, Time Deposit Maturiti

Deposits, Time Deposit Maturities (Details) $ in Thousands	Dec. 31, 2016USD ($)
Time Deposits, Fiscal Year Maturity [Abstract]
2,017	$ 932,179
2,018	276,642
2,019	185,465
2,020	131,820
2,021	76,740
Thereafter	3,281
Total	$ 1,606,127

Deposits (Details Textuals)

Deposits (Details Textuals) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Deposits [Abstract]
Time Deposits, $100,000 or More	$ 571	$ 466
Time Deposits, $250,000 Or More	$ 235	$ 127

Short-term Funding, Composition

Short-term Funding, Composition (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Short-term Debt [Abstract]
Federal funds purchased	$ 208,150	$ 47,870
Securities sold under agreements to repurchase	300,197	383,568
Federal funds purchased and securities sold under agreements to repurchase	508,347	431,438
FHLB advances	482,000	335,000
Commercial paper	101,688	67,978
Other short-term funding	583,688	402,978
Total short-term funding	$ 1,092,035	$ 834,416

Short-term Funding Short-term F

Short-term Funding Short-term Funding, Repurchase Agreements (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Remaining Contractual Maturity of the Agreements
Repurchase agreements	$ 300,197	$ 383,568
Agency mortgage-related securities
Remaining Contractual Maturity of the Agreements
Repurchase agreements	300,197	383,568
Overnight and Continuous
Remaining Contractual Maturity of the Agreements
Repurchase agreements	300,197	383,568
Overnight and Continuous | Agency mortgage-related securities
Remaining Contractual Maturity of the Agreements
Repurchase agreements	300,197	383,568
Up to 30 days
Remaining Contractual Maturity of the Agreements
Repurchase agreements	0	0
Up to 30 days | Agency mortgage-related securities
Remaining Contractual Maturity of the Agreements
Repurchase agreements	0	0
30-90 days
Remaining Contractual Maturity of the Agreements
Repurchase agreements	0	0
30-90 days | Agency mortgage-related securities
Remaining Contractual Maturity of the Agreements
Repurchase agreements	0	0
Greater than 90 days
Remaining Contractual Maturity of the Agreements
Repurchase agreements	0	0
Greater than 90 days | Agency mortgage-related securities
Remaining Contractual Maturity of the Agreements
Repurchase agreements	$ 0	$ 0

Short-term Funding Short-term87

Short-term Funding Short-term Funding (Details Textuals) (Details) $ in Millions	Dec. 31, 2016USD ($)
Short-term Debt [Abstract]
Collateral for repurchase agreements	$ 381

Long-term Funding, Composition

Long-term Funding, Composition (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Long-term Funding
FHLB advances	$ 2,265,188	$ 1,750,225
Senior notes, at par	250,000	680,000
Subordinated notes, at par	250,000	250,000
Other Long-term Debt and Capitalized Costs	(3,393)	(4,061)
Total long-term funding	$ 2,761,795	$ 2,676,164

Long-term Funding, Maturities (

Long-term Funding, Maturities (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Maturities of Long-term Debt [Abstract]
2,017	$ 5
2,018	1,865,000
2,019	498,939
2,020	164
2,021	150,000
Thereafter	247,687
Total long-term funding	$ 2,761,795	$ 2,676,164

Long-term Funding (Textual) (De

Long-term Funding (Textual) (Details) - USD ($) $ in Millions	1 Months Ended
	Nov. 30, 2014	Dec. 31, 2016	Dec. 31, 2015	Sep. 30, 2011	Mar. 31, 2011
Subordinated Borrowing [Line Items]
Federal Home Loan Bank, Advances, Weighted Average Interest Rate		0.50%	0.23%
Long-term Federal Home Loan Bank Advances		$ 6,000
Federal Home Loan Bank Advances		$ 2,700
Two Thousand Eleven Senior Notes [Member]
Subordinated Borrowing [Line Items]
New Senior Debt Issued				$ 130	$ 300
Debt Instrument, Interest Rate, Stated Percentage					5.125%
Two Thousand Fourteen Senior Notes [Member]
Subordinated Borrowing [Line Items]
New Senior Debt Issued	$ 250
Debt Instrument, Interest Rate, Stated Percentage	2.75%
Two Thousand Fourteen Subordinated Notes [Member]
Subordinated Borrowing [Line Items]
Junior Subordinated Debentures Issued	$ 250
Debt Instrument, Term	10 years
Subordinated Borrowing, Interest Rate	4.25%

Stockholders' Equity (Details T

Stockholders' Equity (Details Textuals)	Sep. 15, 2016USD ($)$ / sharesshares	Jun. 15, 2015$ / sharesshares	Sep. 14, 2011$ / sharesshares	Nov. 30, 2008USD ($)$ / shares	Dec. 31, 2016USD ($)$ / sharesshares	Dec. 31, 2015USD ($)$ / sharesshares	Dec. 31, 2014USD ($)	Aug. 28, 2015USD ($)	Jul. 23, 2013USD ($)	Dec. 06, 2011$ / shares
Stockholders' Equity Note [Abstract]
Subsidiary equity balance | $					$ 3,200,000,000
Class of Stock [Line Items]
Common shares, par value (in usd per share)					$ 0.01	$ 0.01
Purchase of preferred stock | $					$ 1,248,000	$ 1,335,000	$ 2,451,000
Series B Preferred Stock
Class of Stock [Line Items]
Stock repurchase program authorized amount | $									$ 10,000,000
Treasury stock shares acquired (in shares) | shares						50,000
Preferred Stock, Dividend Rate, Percentage			8.00%
Depositary shares issued (in shares) | shares			2,600,000
Purchase of preferred stock | $	$ 59,000,000					$ 1,000,000
Preferred Stock, Dividend Payment Terms			September 15, 2016
Redemption Price On Depositary Shares			$ 1,000
Liquidation preference on depositary shares (in usd per share)			1,000
Depositary share value (in usd per share)			$ 25
Series C Preferred Stock
Class of Stock [Line Items]
Stock repurchase program authorized amount | $								$ 10,000,000
Remaining authorized repurchase amount | $					$ 10,000,000
Preferred Stock, Dividend Rate, Percentage		6.125%
Depositary shares issued (in shares) | shares		2,600,000
Depository share ratio		0.025
Preferred Stock, Dividend Payment Terms		June 15, 2020
Redemption Price On Depositary Shares		$ 1,000
Liquidation preference on depositary shares (in usd per share)		1,000
Depositary share value (in usd per share)		$ 25
Series D Preferred Stock
Class of Stock [Line Items]
Preferred Stock, Dividend Rate, Percentage	5.375%
Depositary shares issued (in shares) | shares	4,000,000
Depository share ratio	0.025
Preferred Stock, Dividend Payment Terms	September 15, 2021
Redemption Price On Depositary Shares	$ 1,000
Liquidation preference on depositary shares (in usd per share)	1,000
Depositary share value (in usd per share)	$ 25
Common Stock
Class of Stock [Line Items]
Treasury stock shares acquired (in shares) | shares					1,000,000	5,000,000
Warrants to purchase shares of common stock (in shares) | $				$ 4,000,000
Term of warrants				10 years
Exercise price of warrants (in usd per share)				$ 19.77
Common shares, par value (in usd per share)										$ 0.01
Treasury stock carrying basis | $					$ 20,000,000	$ 93,000,000
Treasury stock acquired average cost per share (in usd per share)					$ 17.10	$ 18.73
Repurchased amount for minimum tax withholding settlement | $					$ 5,000,000	$ 5,000,000
Repurchased shares for minimum tax withholding settlements (in shares) | shares					293,000	285,000
Minimum tax withholding settlement average cost per share (in usd per share)					$ 17.30	$ 17.87
Remaining authorized repurchase amount | $					$ 88,000,000

Stock-Based Compensation, Stock

Stock-Based Compensation, Stock Option Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Fair value assumptions of stock options
Dividend yield	2.50%	2.00%	2.00%
Risk-free interest rate	2.00%	2.00%	2.00%
Weighted average expected volatility	25.00%	20.00%	20.00%
Weighted average expected life	5 years 6 months	6 years	6 years
Weighted average per share fair value of stock options (in usd per share)	$ 3.36	$ 3.08	$ 3
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Stock Options Shares Outstanding, Beginning balance (in shares)		6,629,143
Granted (in shares)	1,302,298
Exercised (in shares)	(1,389,146)
Forfeited or expired (in shares)	(184,452)
Stock Options Shares Outstanding, Ending balance (in shares)	6,357,843		6,629,143
Options exercisable (in shares)	3,632,749
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)		$ 17.22
Granted, Weighted Average Exercise Price (in usd per share)	$ 17.45
Exercised, Weighted Average Exercise Price (in usd per share)	14.81
Forfeited or expired, Weighted Average Exercise Price (in usd per share)	21.62
Stock Options Outstanding, Weighted Average Exercise Price, Ending balance (in usd per share)	17.67		$ 17.22
Options Exercisable, Weighted Average Exercise Price (in usd per share)	$ 17.85
Stock Options Outstanding, Weighted Average Remaining Contractual Term	6 years 1 month 6 days	6 years 2 months 26 days
Options exercisable, Weighted Average Remaining Contractual Term	4 years 5 months 12 days
Stock Options Outstanding, Aggregate Intrinsic Value	$ 47,902		$ 18,730
Options exercisable, Aggregate Intrinsic Value	$ 28,109

Stock-Based Compensation, Nonve

Stock-Based Compensation, Nonvested Stock Option Activity (Details)	12 Months Ended
	Dec. 31, 2016$ / sharesshares
Summary of nonvested stock activity
Granted (in shares)	1,302,298
Nonvested Stock Options [Member]
Summary of nonvested stock activity
Stock Options Shares Outstanding, Beginning balance (in shares)	2,438,898
Granted (in shares)	1,302,298
Vested (in shares)	(909,361)
Forfeited (in shares)	(106,741)
Stock Options Shares Outstanding, Ending balance (in shares)	2,725,094
Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested, Weighted Average Exercise Price [Roll Forward]
Nonvested Weighted Average Grant Date Fair Value, Beginning balance (in usd per share) | $ / shares	$ 3.15
Granted Weighted Average Grant Date Fair Value (in usd per share) | $ / shares	3.36
Vested Weighted Average Grant Date Fair Value (in usd per share) | $ / shares	3.27
Forfeited Weighted Average Grant Date Fair Value (in usd per share) | $ / shares	3.39
Nonvested Weighted Average Grant Date Fair Value, Ending balance (in usd per share) | $ / shares	$ 3.21

Stock-Based Compensation, Restr

Stock-Based Compensation, Restricted Stock Activity (Details)	12 Months Ended
	Dec. 31, 2016$ / 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	2,250,028
Granted (in shares) | shares	1,095,596
Vested (in shares) | shares	(864,617)
Forfeited (in shares) | shares	(103,627)
Outstanding Shares, Ending balance (in shares) | shares	2,377,380
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	$ 17.03
Granted, Weighted Average Grant Date Fair Value (in usd per share) | $ / shares	17.58
Vested, Weighted Average Grant Date Fair Value (in usd per share) | $ / shares	16.62
Forfeited, Weighted Average Grant Date Fair Value (in usd per share) | $ / shares	17.59
Outstanding Weighted Average Grant Date Fair Value, Ending balance (in usd per share) | $ / shares	$ 17.40

Stock-Based Compensation (Detai

Stock-Based Compensation (Details Textuals) - USD ($) $ in Thousands, shares in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unvested share-based payment awards	$ 5,000
Stock Based Compensation (Textuals) [Abstract]
Intrinsic value of stock options exercised	9,000	$ 7,000	$ 4,000
Total fair value of vested stock options	$ 3,000	6,000	7,000
Service-based Restricted Stock Award [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	4 years
Performance-based Restricted Stock Award [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	3 years
Employee Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Recognized compensation expense for accelerated vesting of stock options	$ 940
Recognized compensation expense for vesting of stock options	4,000	4,000	6,000
Restricted Stock Award [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Recognized compensation expense for accelerated vesting of stock options	3,000
Recognized compensation expense for vesting of stock options	18,000	$ 15,000	$ 10,000
Unvested share-based payment awards	$ 20,000
2013 Incentive Compensation Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares remaining available for grant (in shares)	7
2013 Incentive Compensation Plan [Member] | Employee Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expiration term of awards	10 years
2013 Incentive Compensation Plan [Member] | Service-based Restricted Stock Award [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Term of transfer restrictions	4 years
2013 Incentive Compensation Plan [Member] | Performance-based Restricted Stock Award [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Term of transfer restrictions	3 years
Executive Officer [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	4 years	4 years	4 years
Non-executive Employees [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	4 years	4 years	4 years

Retirement Plans, Pension and P

Retirement Plans, Pension and Postretirement Plans Table (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Defined Benefit Plan Disclosure [Line Items]
Fair Value Of Plan Assets As A Percentage Of Net Benefit Obligation	167.00%	169.00%
Change in Fair Value of Plan Assets
Fair value of plan assets at beginning of year	$ 289,599
Fair value of plan assets at end of year	295,718	$ 289,599
Change in Benefit Obligation
Plan amendments	(1,759)	0	$ 0
Retirement Account Plan
Change in Fair Value of Plan Assets
Fair value of plan assets at beginning of year	289,599	303,496
Actual return on plan assets	17,097	495
Employer contributions	0	0
Gross benefits paid	(10,978)	(14,392)
Fair value of plan assets at end of year	295,718	289,599	303,496
Change in Benefit Obligation
Net benefit obligation at beginning of year	171,783	171,333
Service cost	6,780	11,257	11,058
Interest cost	7,121	6,617	7,132
Plan amendments	(823)	0
Actuarial (gain) loss	2,942	(3,032)
Gross benefits paid	(10,978)	(14,392)
Net benefit obligation at end of year	176,825	171,783	171,333
Funded (unfunded) status	118,893	117,816
Noncurrent assets	118,893	117,816
Current liabilities	0	0
Noncurrent liabilities	0	0
Asset (Liability) Recognized in the Consolidated Balance Sheets	118,893	117,816
Postretirement Plan
Change in Fair Value of Plan Assets
Fair value of plan assets at beginning of year	0	0
Actual return on plan assets	0	0
Employer contributions	248	264
Gross benefits paid	(248)	(264)
Fair value of plan assets at end of year	0	0	0
Change in Benefit Obligation
Net benefit obligation at beginning of year	3,436	3,578
Service cost	0	0	0
Interest cost	142	141	150
Plan amendments	(936)	0
Actuarial (gain) loss	9	(19)
Gross benefits paid	(248)	(264)
Net benefit obligation at end of year	2,403	3,436	$ 3,578
Funded (unfunded) status	(2,403)	(3,436)
Noncurrent assets	0	0
Current liabilities	(215)	(274)
Noncurrent liabilities	(2,188)	(3,162)
Asset (Liability) Recognized in the Consolidated Balance Sheets	$ (2,403)	$ (3,436)

Retirement Plans, Amounts Recog

Retirement Plans, Amounts Recognized in Accumulated Other Comprehensive Income Table (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Retirement Account Plan
Defined Benefit Plan Disclosure [Line Items]
Prior service cost	$ (342)	$ 122
Net actuarial loss	35,443	32,879
Amount not yet recognized in net periodic benefit cost, but recognized in accumulated other comprehensive loss	35,101	33,001
Postretirement Plan
Defined Benefit Plan Disclosure [Line Items]
Prior service cost	(580)	0
Net actuarial loss	79	73
Amount not yet recognized in net periodic benefit cost, but recognized in accumulated other comprehensive loss	$ (501)	$ 73

Retirement Plans, Other Changes

Retirement Plans, Other Changes in Plan Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Defined Benefit Plan Disclosure [Line Items]
Amortization of prior service cost	$ (73)	$ 50	$ 58
Amortization of actuarial gain	(4,026)	(15,636)	(17,079)
Plan amendments	1,759	0	0
Income tax (expense) benefit	815	5,873	6,507
Other comprehensive loss on pension and postretirement obligations	(1,525)	(9,713)	$ (10,514)
Postretirement Plan
Defined Benefit Plan Disclosure [Line Items]
Net gain (loss)	(9)	19
Amortization of prior service cost	0	0
Amortization of actuarial gain	0	0
Plan amendments	936	0
Income tax (expense) benefit	(353)	(7)
Other comprehensive loss on pension and postretirement obligations	574	12
Retirement Account Plan
Defined Benefit Plan Disclosure [Line Items]
Net gain (loss)	(6,132)	(17,911)
Amortization of prior service cost	(73)	50
Amortization of actuarial gain	2,115	2,256
Plan amendments	823	0
Income tax (expense) benefit	1,168	5,880
Other comprehensive loss on pension and postretirement obligations	$ (2,099)	$ (9,725)

Retirement Plans, Components of

Retirement Plans, Components of Net Periodic Benefit Cost for the Pension and Postretirement Tables (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Retirement Account Plan
Net period benefit cost for the pension and postretirement plans
Service cost	$ 6,780	$ 11,257	$ 11,058
Interest cost	7,121	6,617	7,132
Expected return on plan assets	(20,287)	(21,438)	(19,922)
Prior service cost	(73)	50	58
Actuarial (gain) loss	2,115	2,256	1,384
Total net pension cost	(4,344)	(1,258)	(290)
Postretirement Plan
Net period benefit cost for the pension and postretirement plans
Service cost	0	0	0
Interest cost	142	141	150
Prior service cost	0	0	0
Actuarial (gain) loss	0	0	(35)
Total net pension cost	$ 142	$ 141	$ 115

Retirement Plans, Weighted Aver

Retirement Plans, Weighted Average Assumptions used to Determine Benefit and Net Periodic Benefit Costs (Details)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Expected long-term rate of return on plan assets	7.00%	7.50%
Retirement Account Plan
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract]
Discount rate	4.10%	4.30%
Rate of increase in compensation levels	4.00%	4.00%
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Discount rate	4.30%	4.00%
Rate of increase in compensation levels	4.00%	4.00%
Expected long-term rate of return on plan assets	7.00%	7.50%
Postretirement Plan
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract]
Discount rate	4.10%	4.30%
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Discount rate	4.30%	4.00%

Retirement Plans, Asset Allocat

Retirement Plans, Asset Allocation for Pension Plan Table (Details)	Dec. 31, 2016	Dec. 31, 2015
Defined Benefit Plan Disclosure [Line Items]
Total	100.00%	100.00%
Equity securities
Defined Benefit Plan Disclosure [Line Items]
Total	60.00%	60.00%
Fixed income securities
Defined Benefit Plan Disclosure [Line Items]
Total	39.00%	40.00%
Other
Defined Benefit Plan Disclosure [Line Items]
Total	1.00%	0.00%

Retirement Plans, Fair Value of

Retirement Plans, Fair Value of Pension Plan Investments Table (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Pension Plan Investments
Money market account	$ 3,624	$ 481
Common /collective trust funds (1)	126,741	120,136
Mutual funds	165,353	168,982
Total Retirement Account Plan Investments	295,718	289,599
Fair Value, Inputs, Level 1
Pension Plan Investments
Money market account	3,624	481
Common /collective trust funds (1)	126,741	120,136
Mutual funds	165,353	168,982
Total Retirement Account Plan Investments	295,718	289,599
Fair Value, Inputs, Level 2
Pension Plan Investments
Money market account	0	0
Common /collective trust funds (1)	0	0
Mutual funds	0	0
Total Retirement Account Plan Investments	0	0
Fair Value, Inputs, Level 3
Pension Plan Investments
Money market account	0	0
Common /collective trust funds (1)	0	0
Mutual funds	0	0
Total Retirement Account Plan Investments	$ 0	$ 0

Retirement Plans, Estimated Fut

Retirement Plans, Estimated Future Benefit Payments (Details) $ in Thousands	Dec. 31, 2016USD ($)
Retirement Account Plan
Defined Benefit Plan Disclosure [Line Items]
2,017	$ 14,829
2,018	14,538
2,019	14,169
2,020	13,815
2,021	13,651
2022 - 2026	71,433
Postretirement Plan
Defined Benefit Plan Disclosure [Line Items]
2,017	215
2,018	199
2,019	179
2,020	177
2,021	174
2022 - 2026	$ 815

Retirement Plans, Effect of 1%

Retirement Plans, Effect of 1% Change in the Assumed Health Care Cost Trend Rate Intro (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Change in assumed health care cost
Effect on total of service and interest cost (increase)	$ 7	$ 15
Effect on total of service and interest cost (decrease)	(6)	(13)
Effect on postretirement benefit obligation (increase)	173	357
Effect on postretirement benefit obligation (decrease)	$ (149)	$ (310)

Retirement Plans (Details Textu

Retirement Plans (Details Textuals) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Retirements Plans [Line Items]
Expected long-term rate of return on plan assets	7.00%	7.50%
Actual return on plan assets percentage	6.36%	0.43%
Total expense related to 401(k)	$ 14	$ 11	$ 10
Actuarial Losses
Retirements Plans [Line Items]
Amounts to be amortized from AOCI next fiscal year	$ 2
Equity Securities
Retirements Plans [Line Items]
Plan asset allocation minimum percentage	50.00%
Plan asset allocation maximum percentage	70.00%
Fixed income securities
Retirements Plans [Line Items]
Plan asset allocation minimum percentage	30.00%
Plan asset allocation maximum percentage	50.00%
Cash and Cash Equivalents
Retirements Plans [Line Items]
Plan asset allocation minimum percentage	0.00%
Plan asset allocation maximum percentage	5.00%
Alternative Securities
Retirements Plans [Line Items]
Plan asset allocation minimum percentage	0.00%
Plan asset allocation maximum percentage	15.00%
Pre-65 Health Care Trend Rate [Member]
Retirements Plans [Line Items]
Health care trend rate assumption	8.00%
Defined Benefit Plan, Health Care Cost Trend, Reduction in Trend Rate Maximum	0.50%
Defined Benefit Plan, Health Care Cost Trend, Reduction in Trend Rate Minimum	0.25%
Ultimate future rate	5.00%
Post-65 Health Care Trend [Member]
Retirements Plans [Line Items]
Health care trend rate assumption	7.50%
Defined Benefit Plan, Health Care Cost Trend, Reduction in Trend Rate Maximum	0.50%
Defined Benefit Plan, Health Care Cost Trend, Reduction in Trend Rate Minimum	0.25%
Ultimate future rate	5.00%
Retirement Account Plan
Retirements Plans [Line Items]
Expected long-term rate of return on plan assets	7.00%	7.50%
Retirement Account Plan | Cash and Cash Equivalents | Prior Service Cost
Retirements Plans [Line Items]
Amounts to be amortized from AOCI next fiscal year	$ 0.1
Postretirement Plan | Cash and Cash Equivalents | Prior Service Cost
Retirements Plans [Line Items]
Amounts to be amortized from AOCI next fiscal year	$ 0.1

Income Taxes, Current and Defer

Income Taxes, Current and Deferred Amounts of Income Tax Expense Table (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Current:
Federal	$ 73,781	$ 82,449	$ 74,646
State	2,885	2,560	1,000
Total current	76,666	85,009	75,646
Deferred:
Federal	3,338	(10,606)	(805)
State	7,318	7,084	10,695
Total deferred	10,656	(3,522)	9,890
Total income tax expense	$ 87,322	$ 81,487	$ 85,536

Income Taxes, Deferred Tax Asse

Income Taxes, Deferred Tax Assets and Liabilities Resulted in Deferred Taxes Table (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Gross deferred tax assets:
Allowance for loan losses	$ 100,891	$ 106,258
Allowance for other losses	11,080	10,906
Accrued liabilities	5,969	6,802
Deferred compensation	33,169	31,677
State net operating losses	7,882	14,154
Nonaccrual interest	1,085	1,901
Net unrealized losses on available-for-sale securities	16,980	219
Net unrealized losses on pension and postretirement benefits	21,218	20,404
Other	8,128	5,811
Total deferred tax assets	206,402	198,132
Gross deferred tax liabilities
FHLB stock dividends	0	2,165
Prepaid expenses	70,943	69,396
Goodwill	27,365	25,770
Mortgage banking activities	17,569	15,704
Deferred loan fee income	16,474	17,770
State deferred taxes	3,800	6,366
Lease financing	1,975	3,042
Bank premises and equipment	7,698	7,491
Other	8,594	9,062
Total deferred tax liabilities	154,418	156,766
Net deferred tax assets	$ 51,984	$ 41,366

Income Taxes, Major Reasons for

Income Taxes, Major Reasons for the Difference in Effective Income Tax Rate from the Federal Tax Rate (Details)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Effective Income Tax Rate Reconciliation
Federal income tax rate at statutory rate	35.00%	35.00%	35.00%
Increases (decreases) resulting from:
Tax-exempt interest and dividends	(4.80%)	(5.00%)	(4.60%)
State income taxes (net of federal benefit)	2.30%	2.30%	2.80%
Bank owned life insurance	(1.70%)	(1.20%)	(1.70%)
Tax effect of tax credits and benefits, net of related expenses	(0.80%)	(0.50%)	(1.40%)
Tax reserve adjustments	0.30%	(0.60%)	0.70%
Other	0.10%	0.20%	0.20%
Effective income tax rate	30.40%	30.20%	31.00%

Income Taxes, Reconciliation of

Income Taxes, Reconciliation of the Beginning and Ending Amount of Unrecognized Tax Benefits Table (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Balance at beginning of year	$ 9	$ 9
Additions (subtractions) for tax positions related to prior years	0	(2)
Additions for tax positions related to current year	1	2
Balance at end of year	$ 10	$ 9

Income Taxes (Details Textuals)

Income Taxes (Details Textuals) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Income Taxes (Textuals) [Abstract]
Bad debt from acquired savings banks	$ 100
Deferred tax on bad debt from acquired savings banks	40
Unrecognized tax benefit impact on effective tax rate	7	$ 6
Interest and penalty expense (benefit)	0	(1)
Accrued interest and penalties	2	2
Operating Loss Carryforwards [Line Items]
Valuation allowance for deferred tax assets	0	$ 0
State and Local Jurisdiction
Operating Loss Carryforwards [Line Items]
Operating tax loss carryforwards	100
Operating tax loss carryforwards from acquisitions	$ 16

Derivative and Hedging Activ111

Derivative and Hedging Activities, Derivative Instruments Not Designated as Hedging Instruments (Details) - Not Designated as Hedging Instrument - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Trading assets | Interest rate-related instruments — customer and mirror
Derivative Instruments Not Designated as Hedging Instruments [Abstract]
Notional Amount	$ 2,039,323	$ 1,665,965
Fair Value	33,671	29,391
Trading assets | Foreign currency exchange forwards
Derivative Instruments Not Designated as Hedging Instruments [Abstract]
Notional Amount	109,675	72,976
Fair Value	2,002	1,532
Trading assets | Commodity contracts
Derivative Instruments Not Designated as Hedging Instruments [Abstract]
Notional Amount	127,582	44,380
Fair Value	16,725	1,269
Trading liabilities | Interest rate-related instruments — customer and mirror
Derivative Instruments Not Designated as Hedging Instruments [Abstract]
Notional Amount	2,039,323	1,665,965
Fair Value	(33,188)	(30,886)
Trading liabilities | Foreign currency exchange forwards
Derivative Instruments Not Designated as Hedging Instruments [Abstract]
Notional Amount	106,251	65,649
Fair Value	(1,943)	(1,398)
Trading liabilities | Commodity contracts
Derivative Instruments Not Designated as Hedging Instruments [Abstract]
Notional Amount	128,368	44,256
Fair Value	(15,972)	(1,146)
Other assets | Interest rate lock commitments (mortgage)
Derivative Instruments Not Designated as Hedging Instruments [Abstract]
Notional Amount	285,345	271,530
Fair Value	206	958
Other assets | Forward commitments (mortgage)
Derivative Instruments Not Designated as Hedging Instruments [Abstract]
Notional Amount	179,600	231,798
Fair Value	2,908	403
Other assets | Purchased options (time deposit)
Derivative Instruments Not Designated as Hedging Instruments [Abstract]
Notional Amount	80,554	104,582
Fair Value	2,576	2,715
Other liabilities | Written options (time deposit)
Derivative Instruments Not Designated as Hedging Instruments [Abstract]
Notional Amount	80,554	104,582
Fair Value	$ (2,576)	$ (2,715)

Derivative and Hedging Activ112

Derivative and Hedging Activities, Income Statement Category of the Gains and Losses (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
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	$ 1,978	$ 854
Capital market fees, net | Foreign currency exchange forwards
Gain (loss) on derivative instruments not designated as hedging instruments
Gain / (Loss) Recognized in Income	(75)	(49)
Capital market fees, net | Commodity contracts
Gain (loss) on derivative instruments not designated as hedging instruments
Gain / (Loss) Recognized in Income	630	123
Mortgage banking, net | Interest rate lock commitments (mortgage)
Gain (loss) on derivative instruments not designated as hedging instruments
Gain / (Loss) Recognized in Income	(752)	(989)
Mortgage banking, net | Forward commitments (mortgage)
Gain (loss) on derivative instruments not designated as hedging instruments
Gain / (Loss) Recognized in Income	$ 2,505	$ 2,838

Derivative and Hedging Activ113

Derivative and Hedging Activities (Details Textuals) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Investment securities and cash equivalents pledged as collateral	$ 40	$ 9
Derivative collateral right to reclaim cash	$ 0	$ 22

Balance Sheet Offsetting (Detai

Balance Sheet Offsetting (Details) - Interest Rate Contract - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	$ 18,031	$ 1,466
Gross amounts offset in the balance sheet	0	0
Net amounts presented in the balance sheet	18,031	1,466
Financial instruments	(18,031)	(1,466)
Collateral	0	0
Net amount	0	0
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	31,075	30,200
Gross amounts offset in the balance sheet	0	0
Net amounts presented in the balance sheet	31,075	30,200
Financial instruments	(18,031)	(1,466)
Collateral	(11,148)	(28,734)
Net amount	$ 1,896	$ 0

Commitments, Off-Balance She115

Commitments, Off-Balance Sheet Arrangements, and Contingent Liabilities, Summary of Lending Related and Other Commitments (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
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	8,131,131	7,402,518
Commercial Letters Of Credit
Summary of lending-related and other commitments
Lending related commitments	7,923	9,945
Standby Letters of Credit
Summary of lending-related and other commitments
Lending related commitments	259,632	296,508
Standby letters of credit, fair value	$ 2,566	$ 2,954

Commitments, Off-Balance She116

Commitments, Off-Balance Sheet Arrangements, and Contingent Liabilities Residential Mortgage Repurchase Reserve (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Residential mortgage repurchase reserve
Balance at beginning of period	$ 24,000
Balance at end of period	25,000	$ 24,000
Mortgage Repurchase Reserve
Residential mortgage repurchase reserve
Balance at beginning of period	1,197	3,258
Repurchase provision expense	456	428
Adjustments to provision expense	(750)	(2,450)
Charge offs, net	(3)	(39)
Balance at end of period	$ 900	$ 1,197

Commitments, Off-Balance She117

Commitments, Off-Balance Sheet Arrangements, and Contingent Liabilities (Details Textuals) $ in Millions	Jan. 11, 2016USD ($)complaint	May 22, 2015USD ($)branchloan_production_office	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)
Commitments, Off-Balance Sheet Arrangements, and Contingent Liabilities (Textuals) [Line Items]
unfunded commitments			$ 25	$ 24
Carrying value of investments			85	52
Commitments under unconsolidated projects			69	61
Commitment term		3 years
Mortgage loan commitment		$ 196
Number of branch opening commitments | branch		1
Number of loan production offices | loan_production_office		4
Conciliation agreement cost, commitment term		4 years
Number of complaints filed under legal proceedings | complaint	2
Loans repurchased under make whole requests			2	3
Loans sold to outside investors original amount			9,200
Loans sold to outside investors remaining outstanding amount			6,100
Residential mortgage loans sold with recourse risk			62	68
Residential mortgage loans sold with credit recourse risk			$ 98	$ 132
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
Damages sought, cash	4
American Funds Service Company v Associated Bank [Member]
Commitments, Off-Balance Sheet Arrangements, and Contingent Liabilities (Textuals) [Line Items]
Damages sought	$ 0.6

Parent Company Only Financia118

Parent Company Only Financial Information, Balance Sheet (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
ASSETS
Cash and due from banks	$ 446,558	$ 374,921
Investment securities available for sale, at fair value	4,680,226	4,967,414
Other assets	1,074,937	1,043,831
Total assets	29,139,315	27,711,835
LIABILITIES AND STOCKHOLDERS’ EQUITY
Commercial paper	101,688	67,978
Senior notes, at par	250,000	680,000
Subordinated notes, at par	250,000	250,000
Other Long-term Debt and Capitalized Costs	(3,393)	(4,061)
Total long-term funding	2,761,795	2,676,164
Accrued expenses and other liabilities	254,622	222,914
Total liabilities	26,048,003	24,774,589
Preferred equity	159,929	121,379
Common equity	1,630	1,642
Total stockholders’ equity	3,091,312	2,937,246	$ 2,800,251	$ 2,891,290
Total liabilities and stockholders’ equity	29,139,315	27,711,835
Associated Banc-Corp
ASSETS
Cash and due from banks	402,786	610,862
Investment securities available for sale, at fair value	14,389	61,847
Investment in subsidiaries	3,248,763	3,211,685
Other assets	61,242	70,595
Total assets	3,727,180	3,954,989
LIABILITIES AND STOCKHOLDERS’ EQUITY
Commercial paper	101,688	67,978
Senior notes, at par	250,000	680,000
Subordinated notes, at par	250,000	250,000
Other Long-term Debt and Capitalized Costs	(3,393)	(4,061)
Total long-term funding	496,607	925,939
Accrued expenses and other liabilities	37,573	23,826
Total liabilities	635,868	1,017,743
Preferred equity	159,929	121,379
Common equity	2,931,383	2,815,867
Total stockholders’ equity	3,091,312	2,937,246
Total liabilities and stockholders’ equity	$ 3,727,180	$ 3,954,989

Parent Company Only Financia119

Parent Company Only Financial Information, Statement of Income (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
INCOME
Interest income on notes receivable	$ 659,538	$ 615,627	$ 598,582
Total income	(1,060,156)	(1,005,635)	(971,828)
EXPENSE
Income before income taxes	287,596	269,788	276,045
Income tax expense	87,322	81,487	85,536
Net income	200,274	188,301	190,509
Preferred stock dividends	(8,903)	(7,155)	(5,002)
Net income available to common equity	191,371	181,146	185,507
Associated Banc-Corp
INCOME
Dividends from subsidiaries	188,000	205,000	223,000
Interest income on notes receivable	0	0	1,264
Other income	4,669	8,441	9,713
Total income	(192,669)	(213,441)	(233,977)
EXPENSE
Interest expense on short and long-term funding	21,901	39,576	24,847
Other expense	4,289	4,684	776
Total expense	26,190	44,260	25,623
Income before income taxes	166,479	169,181	208,354
Income tax expense	3,468	(1,665)	(5,801)
Income before equity in undistributed net income (loss) of subsidiaries	163,011	170,846	214,155
Equity in undistributed net income (loss) of subsidiaries	37,263	17,455	(23,646)
Net income	200,274	188,301	190,509
Preferred stock dividends	8,903	7,155	5,002
Net income available to common equity	$ 191,371	$ 181,146	$ 185,507

Parent Company Only Financia120

Parent Company Only Financial Information, Statement of Cash Flows (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
CASH FLOWS FROM OPERATING ACTIVITIES
Net income	$ 200,274	$ 188,301	$ 190,509
Adjustments to reconcile net income to net cash provided by operating activities:
Gain on sales of investment securities, net	(9,316)	(8,133)	(494)
Asset (gains) losses, net	86	(2,540)	(10,830)
Net change in other assets and other liabilities	21,915	(9,565)	(3,661)
Net cash provided by operating activities	628,942	301,744	199,509
CASH FLOWS FROM INVESTING ACTIVITIES
Proceeds from sales of investment securities	549,555	1,601,947	102,011
Net cash used in investing activities	(1,640,582)	(1,534,356)	(2,118,605)
CASH FLOWS FROM FINANCING ACTIVITIES
Net increase (decrease) in short-term funding	257,619	(233,872)	327,362
Repayment of long-term funding	(1,180,038)	(1,500,035)	(155,066)
Proceeds from issuance of long-term funding	1,265,000	250,000	996,030
Proceeds from issuance of common stock for stock-based compensation plans	21,748	20,054	13,228
Proceeds from issuance of preferred shares	97,066	62,966	0
Redemption of preferred stock	58,903	0	0
Purchase of preferred stock	(1,248)	(1,335)	(2,451)
Purchase of common stock returned to authorized but unissued	(20,007)	(93,000)	(150,498)
Purchase of treasury stock	0	0	(108,600)
payments for repurchase of common stock for tax withholding	5,074	5,154	3,712
Payments of Ordinary Dividends, Common Stock	67,855	62,400	58,710
Payments of Ordinary Dividends, Preferred Stock and Preference Stock	8,903	7,155	5,002
Net cash provided by financing activities	1,180,188	674,230	2,348,918
Net increase (decrease) in cash and cash equivalents	168,548	(558,382)	429,822
Cash and cash equivalents at beginning of period	473,685	1,032,067	602,245
Cash and cash equivalents at end of period	642,233	473,685	1,032,067
Associated Banc-Corp
CASH FLOWS FROM OPERATING ACTIVITIES
Net income	200,274	188,301	190,509
Adjustments to reconcile net income to net cash provided by operating activities:
(Increase) decrease in equity in undistributed net income of subsidiaries	(37,263)	(17,455)	23,646
Gain on sales of investment securities, net	(466)	0	(214)
Asset (gains) losses, net	(793)	(5,673)	(5,609)
Net change in other assets and other liabilities	19,708	(10,997)	(14,022)
Net cash provided by operating activities	181,460	154,176	194,310
CASH FLOWS FROM INVESTING ACTIVITIES
Proceeds from sales of investment securities	47,719	13,962	88,844
Net decrease in notes receivable	0	0	46,594
Purchase of other assets, net of disposals	2,211	11,964	10,930
Net cash used in investing activities	49,930	25,926	146,368
CASH FLOWS FROM FINANCING ACTIVITIES
Net increase (decrease) in short-term funding	33,710	(6,319)	8,813
Repayment of long-term funding	(430,000)	0	(155,000)
Proceeds from issuance of long-term funding	0	0	496,030
Proceeds from issuance of common stock for stock-based compensation plans	21,748	20,054	13,228
Proceeds from issuance of preferred shares	97,066	62,966	0
Redemption of preferred stock	(58,903)	0	0
Purchase of preferred stock	(1,248)	(1,335)	(2,451)
Purchase of common stock returned to authorized but unissued	(20,007)	(93,000)	(150,498)
Purchase of treasury stock	0	0	(108,600)
payments for repurchase of common stock for tax withholding	5,074	5,154	3,712
Payments of Ordinary Dividends, Common Stock	(67,855)	(62,400)	(58,710)
Payments of Ordinary Dividends, Preferred Stock and Preference Stock	(8,903)	(7,155)	(5,002)
Net cash provided by financing activities	(439,466)	(92,343)	34,098
Net increase (decrease) in cash and cash equivalents	(208,076)	87,759	374,776
Cash and cash equivalents at beginning of period	610,862	523,103	148,327
Cash and cash equivalents at end of period	$ 402,786	$ 610,862	$ 523,103

Regulatory Matters (Details)

Regulatory Matters (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Associated Banc-Corp
Regulatory Capital [Abstract]
Total Capital Actual Amount	$ 2,706,760	$ 2,515,861
Total Capital Actual Ratio	12.68%	12.62%
Total Capital for Capital Adequacy Purposes Amount	$ 1,707,276	$ 1,594,397
Total Capital for Adequacy Purposes Ratio	8.00%	8.00%
Tier 1 Capital Actual Amount	$ 2,191,798	$ 2,016,861
Tier 1 Capital Actual Ratio	10.27%	10.12%
Tier 1 Capital for Adequacy Purposes Amount	$ 1,280,457	$ 1,195,798
Tier 1 Capital for Adequacy Purposes Ratio	6.00%	6.00%
Common Equity Tier One Capital	$ 2,032,587	$ 1,897,944
Common Equity Tier One Capital to Risk Weighted Assets	9.52%	9.52%
Common Equity Tier One Capital Required for Capital Adequacy	$ 960,343	$ 896,848
Common Equity Tier One Capital Required for Capital Adequacy to Risk Weighted Assets	4.50%	4.50%
Tier 1 Leverage Capital Actual Amount	$ 2,191,798	$ 2,016,861
Tier 1 Leverage Capital Actual Ratio	7.83%	7.60%
Tier 1 Leverage Capital for Adequacy Purposes Amount	$ 1,119,685	$ 1,061,325
Tier 1 Leverage Capital for Adequacy Purposes Ratio	4.00%	4.00%
Associated Bank, N.A.
Regulatory Capital [Abstract]
Total Capital Actual Amount	$ 2,565,062	$ 2,532,563
Total Capital Actual Ratio	12.07%	12.76%
Total Capital for Capital Adequacy Purposes Amount	$ 1,700,737	$ 1,588,070
Total Capital for Adequacy Purposes Ratio	8.00%	8.00%
Total Capital to be Well Capitalized Amount	$ 2,125,921	$ 1,985,088
Total Capital to be Well Capitalized Ratio	10.00%	10.00%
Tier 1 Capital Actual Amount	$ 2,298,812	$ 2,283,785
Tier 1 Capital Actual Ratio	10.81%	11.50%
Tier 1 Capital for Adequacy Purposes Amount	$ 1,275,553	$ 1,191,053
Tier 1 Capital for Adequacy Purposes Ratio	6.00%	6.00%
Tier 1 Capital To Be Well Capitalized Amount	$ 1,700,737	$ 1,588,070
Tier 1 Capital To Be Well Capitalized Ratio	8.00%	8.00%
Common Equity Tier One Capital	$ 2,098,812	$ 2,084,589
Common Equity Tier One Capital to Risk Weighted Assets	9.87%	10.50%
Common Equity Tier One Capital Required for Capital Adequacy	$ 956,664	$ 893,289
Common Equity Tier One Capital Required for Capital Adequacy to Risk Weighted Assets	4.50%	4.50%
Tier 1 Equity Capital to be Well Capitalized Amount	$ 1,381,849	$ 1,290,307
Tier 1 Equity Capital to be Well Capitalized Ratio	6.50%	6.50%
Tier 1 Leverage Capital Actual Amount	$ 2,298,812	$ 2,283,785
Tier 1 Leverage Capital Actual Ratio	8.24%	8.64%
Tier 1 Leverage Capital for Adequacy Purposes Amount	$ 1,115,731	$ 1,057,228
Tier 1 Leverage Capital for Adequacy Purposes Ratio	4.00%	4.00%
Tier 1 Leverage Capital To Be Well Capitalized Amount	$ 1,394,663	$ 1,321,535
Tier 1 Leverage Capital To Be Well Capitalized Ratio	5.00%	5.00%

Regulatory Matters (Details Tex

Regulatory Matters (Details Textuals) $ in Millions	Dec. 31, 2016USD ($)
Regulatory Capital Requirements [Abstract]
Required minimum cash and reserve balances	$ 115

Earnings Per Common Share (Deta

Earnings Per Common Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Calculations for basic and diluted earnings per common share
Net income	$ 200,274	$ 188,301	$ 190,509
Preferred stock dividends	(8,903)	(7,155)	(5,002)
Net income available to common equity	191,371	181,146	185,507
Common shareholder dividends	(67,100)	(61,774)	(58,123)
Unvested share-based payment awards	(755)	(626)	(587)
Undistributed earnings	123,516	118,746	126,797
Undistributed earnings allocated to common shareholders	122,205	117,498	125,646
Undistributed earnings allocated to unvested share-based payment awards	1,311	1,248	1,151
Undistributed earnings	123,516	118,746	126,797
Basic
Distributed earnings to common shareholders	67,100	61,774	58,123
Undistributed earnings allocated to common shareholders	122,205	117,498	125,646
Total common shareholders earnings, basic	189,305	179,272	183,769
Diluted
Distributed earnings to common shareholders	67,100	61,774	58,123
Undistributed earnings allocated to common shareholders	122,205	117,498	125,646
Total common shareholders earnings, diluted	$ 189,305	$ 179,272	$ 183,769
Weighted average common shares outstanding (in shares)	148,769	149,350	157,286
Effect of dilutive common stock awards (in shares)	1,192	1,253	968
Diluted weighted average common shares outstanding (in shares)	149,961	150,603	158,254
Basic earnings (loss) per common share (in usd per share)	$ 1.27	$ 1.20	$ 1.17
Diluted earnings (loss) per common share (in usd per share)	$ 1.26	$ 1.19	$ 1.16

Earnings Per Common Share (Text

Earnings Per Common Share (Textual) (Details) - shares shares in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Earnings Per Share Textuals [Abstract]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	1	1	2
Incremental Common Shares Attributable to Dilutive Effect of Call Options and Warrants	4	4	4

Segment Reporting (Details)

Segment Reporting (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Segment Income Statement Data Abstract
Net interest income	$ 707,273	$ 676,278	$ 680,967
Noninterest income	352,883	329,357	290,861
Total income	1,060,156	1,005,635	971,828
Credit provision	70,000	37,500	16,000
Noninterest expense	702,560	698,347	679,783
Income before income taxes	287,596	269,788	276,045
Income tax expense (benefit)	87,322	81,487	85,536
Net income	$ 200,274	$ 188,301	$ 190,509
Return on average allocated capital (ROCET1)	9.90%	9.90%	9.90%
Segment Balance Sheet Data
Average earning assets	$ 26,026,661	$ 24,571,087	$ 22,760,128
Average loans	19,650,667	18,252,264	16,838,994
Average deposits	21,005,772	19,903,087	17,647,084
Average allocated capital (CET1)	1,940,391	1,833,597	1,870,609
Operating Segments | Corporate and Commercial Specialty
Segment Income Statement Data Abstract
Net interest income	328,603	310,072	296,717
Noninterest income	47,776	46,742	49,213
Total income	376,379	356,814	345,930
Credit provision	50,397	41,913	46,857
Noninterest expense	148,493	141,912	148,476
Income before income taxes	177,489	172,989	150,597
Income tax expense (benefit)	59,261	59,200	50,039
Net income	$ 118,228	$ 113,789	$ 100,558
Return on average allocated capital (ROCET1)	11.00%	11.60%	11.10%
Segment Balance Sheet Data
Average earning assets	$ 10,178,813	$ 9,383,971	$ 8,927,401
Average loans	10,169,300	9,374,191	8,915,498
Average deposits	5,904,238	5,856,530	5,148,195
Average allocated capital (CET1)	1,070,598	977,406	903,500
Operating Segments | Community, Consumer, and Business
Segment Income Statement Data Abstract
Net interest income	350,551	349,134	310,444
Noninterest income	277,942	265,503	221,430
Total income	628,493	614,637	531,874
Credit provision	24,185	25,614	23,934
Noninterest expense	502,285	492,284	463,235
Income before income taxes	102,023	96,739	44,705
Income tax expense (benefit)	35,708	33,859	15,647
Net income	$ 66,315	$ 62,880	$ 29,058
Return on average allocated capital (ROCET1)	10.50%	9.80%	5.10%
Segment Balance Sheet Data
Average earning assets	$ 9,309,028	$ 8,810,015	$ 7,840,352
Average loans	9,307,723	8,809,673	7,840,352
Average deposits	11,451,759	10,898,602	10,061,495
Average allocated capital (CET1)	629,540	640,181	564,303
Operating Segments | Risk Management and Shared Services
Segment Income Statement Data Abstract
Net interest income	28,119	17,072	73,806
Noninterest income	27,165	17,112	20,218
Total income	55,284	34,184	94,024
Credit provision	(4,582)	(30,027)	(54,791)
Noninterest expense	51,782	64,151	68,072
Income before income taxes	8,084	60	80,743
Income tax expense (benefit)	(7,647)	(11,572)	19,850
Net income	$ 15,731	$ 11,632	$ 60,893
Return on average allocated capital (ROCET1)	2.80%	2.10%	13.90%
Segment Balance Sheet Data
Average earning assets	$ 6,538,820	$ 6,377,101	$ 5,992,375
Average loans	173,644	68,400	83,144
Average deposits	3,649,775	3,147,955	2,437,394
Average allocated capital (CET1)	$ 240,253	$ 216,010	$ 402,806

Segment Reporting (Details Text

Segment Reporting (Details Textuals) $ in Millions	12 Months Ended
	Dec. 31, 2016segment	Dec. 31, 2015USD ($)
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Number of Reportable Segments | segment	3
Segment FTP Methodology Change Impact
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative Effect of New Accounting Principle in Period of Adoption | $		$ 30

Accumulated Other Comprehens127

Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	$ (32,616)
Personnel expense	(414,837)	$ (404,741)	$ (390,399)
Interest income	(5,887)	(555)	0
Total other comprehensive income (loss)	(22,063)	(27,766)	19,394
Ending Balance	(54,679)	(32,616)
Investments Securities Available For Sale
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	459	18,512	(11,396)
Other comprehensive income (loss) before reclassifications	(17,900)	(20,439)	49,038
Investment securities gain, net	(9,316)	(8,133)	(494)
Personnel expense	0	0	0
Interest income	(5,887)	(555)
Income tax (expense) benefit	12,565	11,074	(18,636)
Total other comprehensive income (loss)	(20,538)	(18,053)	29,908
Ending Balance	(20,079)	459	18,512
Defined Benefit Pension and Postretirement Obligations
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	(33,075)	(23,362)	(12,848)
Other comprehensive income (loss) before reclassifications	(6,141)	(17,892)	(18,428)
Investment securities gain, net	0	0	0
Personnel expense	3,801	2,306	1,407
Interest income	0	0
Income tax (expense) benefit	815	5,873	6,507
Total other comprehensive income (loss)	(1,525)	(9,713)	(10,514)
Ending Balance	(34,600)	(33,075)	(23,362)
Accumulated Other Comprehensive Income (Loss)
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	(32,616)	(4,850)	(24,244)
Other comprehensive income (loss) before reclassifications	(24,041)	(38,331)	30,610
Investment securities gain, net	(9,316)	(8,133)	(494)
Personnel expense	3,801	2,306	1,407
Interest income	(5,887)	(555)
Income tax (expense) benefit	13,380	16,947	(12,129)
Total other comprehensive income (loss)	(22,063)	(27,766)	19,394
Ending Balance	$ (54,679)	$ (32,616)	$ (4,850)