Associated Banc-Corp (ASB) 10-K 5 Feb 16 2015 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2015	Feb. 03, 2016	Jun. 30, 2015
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, 2015
Amendment Flag	false
Document Fiscal Year Focus	2,015
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			$ 3,022,670,000
Entity Common Stock, Shares Outstanding		149,705,825

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
ASSETS
Cash and due from banks	$ 374,921	$ 444,113
Interest-bearing deposits in other financial institutions	79,764	571,924
Federal funds sold and securities purchased under agreements to resell	19,000	16,030
Investment securities held to maturity, at amortized cost	1,168,230	404,455
Investment securities available for sale, at fair value	4,967,414	5,396,812
Federal Home Loan Bank and Federal Reserve Bank stocks, at cost	147,240	189,107
Loans held for sale	124,915	154,935
Loans	18,714,343	17,593,846
Allowance for loan losses	(274,264)	(266,302)
Loans, net	18,440,079	17,327,544
Premises and equipment, net	267,606	274,688
Goodwill	968,844	929,168
Mortgage servicing rights	61,341	60,145
Other intangible assets	16,458	7,437
Trading assets	32,192	35,163
Other assets	1,047,017	1,010,253
Total assets	27,715,021	26,821,774
LIABILITIES AND STOCKHOLDERS’ EQUITY
Noninterest-bearing demand deposits	5,562,466	4,505,272
Interest-bearing deposits	15,445,199	14,258,232
Total deposits	21,007,665	18,763,504
Federal funds purchased and securities sold under agreements to repurchase	431,438	493,991
Other short-term funding	402,978	574,297
Long-term funding	2,679,350	3,930,117
Trading liabilities	33,430	37,329
Accrued expenses and other liabilities	222,914	222,285
Total liabilities	24,777,775	24,021,523
Stockholders’ equity
Preferred equity	121,379	59,727
Common stock	1,642	1,665
Surplus	1,458,522	1,484,933
Retained earnings	1,593,239	1,497,818
Accumulated other comprehensive loss	(32,616)	(4,850)
Treasury stock, at cost	(204,920)	(239,042)
Total stockholders’ equity	2,937,246	2,800,251
Total liabilities and stockholders’ equity	$ 27,715,021	$ 26,821,774
Preferred shares issued (in shares)	125,114	61,356
Preferred shares authorized (par value $1.00 per share) (in shares)	750,000	750,000
Common shares issued (in shares)	164,200,068	166,544,252
Common shares authorized (par value $0.01 per share) (in shares)	250,000,000	250,000,000
Treasury shares of common stock (in shares)	12,960,636	15,002,318

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2015	Dec. 31, 2014
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, 2015	Dec. 31, 2014	Dec. 31, 2013
INTEREST INCOME
Interest and fees on loans	$ 615,627	$ 598,582	$ 587,526
Interest and dividends on investment securities:
Taxable	100,292	102,464	88,919
Tax exempt	31,152	29,064	27,345
Other interest	6,591	6,635	5,193
Total interest income	753,662	736,745	708,983
INTEREST EXPENSE
Interest on deposits	33,125	26,294	31,267
Interest on Federal funds purchased and securities sold under agreements to repurchase	943	1,219	1,322
Interest on other short-term funding	465	785	1,519
Interest on long-term funding	42,851	27,480	29,332
Total interest expense	77,384	55,778	63,440
NET INTEREST INCOME	676,278	680,967	645,543
Provision for credit losses	37,500	16,000	10,100
Net interest income after provision for credit losses	638,778	664,967	635,443
NONINTEREST INCOME
Trust service fees	48,840	48,403	45,633
Service charges on deposit accounts	65,471	68,779	70,009
Card-based and other nondeposit fees	51,325	49,512	49,913
Insurance commissions	75,363	44,421	44,024
Brokerage and annuity commissions	15,378	16,089	14,877
Total core fee-based revenue	256,377	227,204	224,456
Mortgage banking, net	32,263	21,320	48,847
Capital market fees, net	10,752	9,973	13,080
Bank owned life insurance income	9,796	13,576	11,855
Asset gains, net	1,592	10,288	5,413
Investment securities gains, net	8,133	494	564
Other	9,496	7,464	8,884
Total noninterest income	328,409	290,319	313,099
NONINTEREST EXPENSE
Personnel expense	404,741	390,399	397,015
Occupancy	60,896	57,677	59,409
Equipment	23,209	24,784	25,351
Technology	60,613	55,472	49,445
Business development and advertising	25,772	26,144	23,346
Other intangible amortization	3,094	3,747	4,043
Loan expense	14,102	13,866	13,162
Legal and professional fees	17,052	17,485	20,226
Foreclosure / OREO expense	4,494	6,722	10,068
FDIC expense	26,000	23,761	19,461
Other	57,426	59,184	59,123
Total noninterest expense	697,399	679,241	680,649
Income before income taxes	269,788	276,045	267,893
Income tax expense	81,487	85,536	79,201
Net income	188,301	190,509	188,692
Preferred stock dividends	7,155	5,002	5,158
Net income available to common equity	$ 181,146	$ 185,507	$ 183,534
Earnings per common share:
Basic (in usd per share)	$ 1.20	$ 1.17	$ 1.10
Diluted (in usd per share)	$ 1.19	$ 1.16	$ 1.10
Average common shares outstanding:
Basic (in shares)	149,350	157,286	165,584
Diluted (in shares)	150,603	158,254	165,802

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Statement of Comprehensive Income [Abstract]
Net income	$ 188,301	$ 190,509	$ 188,692
Investment securities available for sale:
Net unrealized gains (losses)	(37,873)	49,038	(158,207)
Net unrealized gains on available for sale securities transferred to held to maturity securities	16,879	0	0
Reclassification adjustment for net gains realized in net income	(8,133)	(494)	(564)
Income tax (expense) benefit	11,074	(18,636)	61,266
Other comprehensive income (loss) on investment securities available for sale	(18,053)	29,908	(97,505)
Defined benefit pension and postretirement obligations:
Prior service cost, net of amortization	50	58	72
Net gain (loss), net of amortization	(15,636)	(17,079)	40,148
Income tax (expense) benefit	5,873	6,507	(15,562)
Other comprehensive income (loss) on pension and postretirement obligations	(9,713)	(10,514)	24,658
Total other comprehensive income (loss)	(27,766)	19,394	(72,847)
Comprehensive income	$ 160,535	$ 209,903	$ 115,845

Consolidated Statements of Chan

Consolidated Statements of Changes in Stockholders' Equity - USD ($) shares in Thousands, $ in Thousands	Total	Preferred Equity [Member]	Common Stock [Member]	Surplus [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Treasury Stock [Member]
Beginning balance at Dec. 31, 2012	$ 2,936,399	$ 63,272	$ 1,750	$ 1,602,136	$ 1,281,811	$ 48,603	$ (61,173)
Common stock shares outstanding, beginning balance (in shares) at Dec. 31, 2012			175,013
Preferred stock shares outstanding, beginning balance (in shares) at Dec. 31, 2012		65
Comprehensive income:
Net income	188,692	$ 0	$ 0	0	188,692	0	0
Other comprehensive loss	(72,847)	$ 0	$ 0	0	0	(72,847)	0
Comprehensive income	115,845
Common stock issued:
Stock-based compensation plans, net (in shares)		0	0
Stock-based compensation plans, net	9,305	$ 0	$ 0	989	(17,630)	0	25,946
Purchase of treasury stock	(123,349)	0	0	0	0	0	(123,349)
Cash dividends:
Common stock dividends	(54,991)	0	0	0	(54,991)	0	0
Preferred stock dividends	(5,158)	$ 0	$ 0	0	(5,158)	0	0
Purchase of preferred stock (in shares)		(1)	0
Purchase of preferred stock	1,626	$ 1,410	$ 0	0	216	0	0
Stock-based compensation expense, net	14,840	0	0	14,840	0	0	0
Tax impact of stock-based compensation	25	0	0	25	0	0	0
Ending 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, ending balance (in shares) at Dec. 31, 2013			175,013
Preferred stock shares outstanding, ending balance (in shares) at Dec. 31, 2013		64
Comprehensive income:
Net income	190,509	$ 0	$ 0	0	190,509	0	0
Other comprehensive loss	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 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
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
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 loss	(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 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
Purchase of preferred stock (in shares)		(2)	0
Purchase of preferred stock	1,335	$ 1,209	$ 0	0	126	0	0
Other (in shares)		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
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
Issuance of preferred stock (in shares)		(65)	0
Issuance of preferred stock	62,966	$ 62,966	$ 0	0	0	0	0
Other	(766)	(105)	0	0	(661)	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

Consolidated Statements of Cha7

Consolidated Statements of Changes in Stockholders' Equity (Parenthetical) - $ / shares	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Common Stock [Member]
Cash dividends:
Common stock, per share	$ 0.41	$ 0.37	$ 0.33

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
CASH FLOWS FROM OPERATING ACTIVITIES
Net income	$ 188,301	$ 190,509	$ 188,692
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for credit losses	37,500	16,000	10,100
Depreciation and amortization	47,168	50,281	49,711
(Recovery of) addition to valuation allowance on mortgage servicing rights, net	(425)	321	(14,563)
Amortization of mortgage servicing rights	11,601	11,067	15,488
Amortization of other intangible assets	3,094	3,747	4,043
Amortization and accretion on earning assets, funding, and other, net	39,806	28,145	44,965
Deferred income taxes	(3,522)	9,890	25,920
Tax impact of stock based compensation	(1,518)	1,288	(25)
Gain on sales of investment securities, net	(8,133)	(494)	(564)
Gain on sales of assets and impairment write-downs, net	(1,592)	(10,288)	(5,413)
Gain on mortgage banking activities, net	(20,258)	(13,765)	(34,268)
Mortgage loans originated and acquired for sale	(1,228,106)	(1,069,852)	(2,304,006)
Proceeds from sales of mortgage loans held for sale	1,241,012	1,010,167	2,516,690
Pension contributions	0	(21,000)	(28,000)
(Increase) decrease in interest receivable	395	(1,264)	2,078
Increase (decrease) in interest payable	3,898	1,536	(2,214)
Other, net	(10,513)	(4,203)	9,274
Net cash provided by operating activities	301,744	199,509	477,958
CASH FLOWS FROM INVESTING ACTIVITIES
Net increase in loans	(1,136,793)	(1,736,571)	(593,591)
Purchases of:
Available for sale securities	(2,859,793)	(1,096,410)	(1,954,936)
Held to maturity securities	(250,767)	(229,795)	(135,785)
Federal Home Loan Bank and Federal Reserve Bank stocks	(35,647)	(7,857)	(28,399)
Premises, equipment, and software, net of disposals	(54,636)	(50,396)	(67,723)
Other assets	(15,187)	(4,496)	(2,098)
Proceeds from:
Sales of available for sale securities	1,601,947	102,011	136,152
Sale of Federal Home Loan Bank and Federal Reserve Bank stocks	77,514	0	14,399
Prepayments, calls, and maturities of available for sale securities	1,099,625	862,037	1,298,077
Prepayments, calls, and maturities of held to maturity securities	17,013	6,420	0
Prepayments, calls and maturities of other assets	21,236	36,452	41,668
Sales of loans originated for investment	0	0	39,002
Net cash received in acquisition	1,132	0	0
Net cash used in investing activities	(1,534,356)	(2,118,605)	(1,253,234)
CASH FLOWS FROM FINANCING ACTIVITIES
Net increase in deposits	2,244,161	1,496,337	394,340
Net decrease in deposits due to branch sales	0	0	(65,430)
Net increase (decrease) in short-term funding	(233,872)	327,362	(1,586,013)
Repayment of long-term funding	(1,500,035)	(155,066)	(427,430)
Proceeds from issuance of long-term funding	250,000	996,030	2,500,000
Proceeds from issuance of preferred shares	62,966	0	0
Proceeds from issuance of common stock for stock-based compensation plans	20,054	13,228	9,305
Purchase of preferred stock	(1,335)	(2,451)	(1,626)
Purchase of common stock returned to authorized but unissued	(93,000)	(150,498)	0
Purchase of treasury stock	(5,154)	(112,312)	(123,349)
Cash dividends on common stock	(62,400)	(58,710)	(54,991)
Cash dividends on preferred stock	(7,155)	(5,002)	(5,158)
Net cash provided by financing activities	674,230	2,348,918	639,648
Net increase (decrease) in cash and cash equivalents	(558,382)	429,822	(135,628)
Cash and cash equivalents at beginning of period	1,032,067	602,245	737,873
Cash and cash equivalents at end of period	473,685	1,032,067	602,245
Supplemental disclosures of cash flow information:
Cash paid for interest	73,054	54,330	65,552
Cash paid for income taxes	84,407	72,431	49,200
Loans and bank premises transferred to other real estate owned	10,988	21,413	26,151
Capitalized mortgage servicing rights	12,372	8,253	18,256
Fair value of assets acquired, including cash and cash equivalents	4,590	0	0
Fair value ascribed to goodwill and intangible assets	51,791	0	0
Fair value of liabilities assumed	12,851	0	0
Common stock issued in acquisition	$ 43,530	$ 0	$ 0

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2015
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	NOTE 1 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 the third quarter of 2015, the Corporation reclassified all closed end first lien home equity loans to residential mortgage loans in order to better align with the Corporation's regulatory reporting of residential mortgage loan products. All prior periods have been restated to reflect this change. As a result, the restated home equity loan portfolio is $1.1 billion at December 31, 2014, compared to the originally reported amount of $1.6 billion . Similarly, the restated residential mortgage loan portfolio is $5.1 billion at December 31, 2014, compared to the originally reported amount of $4.5 billion . 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 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. 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. 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. All restructured loans are disclosed as restructured loans in the calendar year of restructuring. In subsequent years, a restructured loan modified at a market rate that has performed according to the modified terms for at least six months will cease being disclosed as a restructured loan. A loan that has been modified at a below market rate will return to performing status if it satisfies the six month performance requirement; however, it will remain classified as a restructured loan. See Note 4 for additional information on restructured loans. 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. At December 31, 2015 , the carrying value of loans held for sale included a market valuation adjustment of $155,000 , while at December 31, 2014 , there was no market valuation adjustment to loans held for sale. 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. 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. 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, installment loans and credit cards, are collectively evaluated for impairment. Interest income on impaired loans 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. 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. Other real estate owned totaled $15 million and $17 million at December 31, 2015 and 2014 , respectively. 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 and 14 years for 2015 and 2014, respectively). 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, 2015 and 2014 , 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, 2015 and 2014 , 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 en

Acquisition

Acquisition	12 Months Ended
	Dec. 31, 2015
Business Combinations [Abstract]
Acquisition	NOTE 2 ACQUISITION: On February 17, 2015, the Corporation acquired Ahmann & Martin Co., a risk and employee benefits consulting firm based in Minnesota. The firm merged into Associated Financial Group, LLC, the Corporation's insurance brokerage subsidiary. The Corporation's acquisition of Ahmann & Martin Co. enhances 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.

Investment Securities

Investment Securities	12 Months Ended
	Dec. 31, 2015
Investments, Debt and Equity Securities [Abstract]
Investment Securities	NOTE 3 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 government-sponsored enterprises ("GSE") such as the Federal National Mortgage Association (“FNMA”) and the Federal Home Loan Mortgage Corporation (“FHLMC”). The amortized cost and fair values of securities available for sale and held to maturity were as follows. December 31, 2015 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses 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: Obligations of state and political subdivisions (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 December 31, 2014 Amortized Gross Gross Fair Value ($ in Thousands) Investment securities available for sale: U. S. Treasury securities $ 999 $ — $ (1 ) $ 998 Municipal securities 560,839 21,869 (29 ) 582,679 Residential mortgage-related securities: FNMA / FHLMC 3,534,240 59,640 (30,423 ) 3,563,457 GNMA 165,863 1,596 (127 ) 167,332 Private-label 2,297 7 (10 ) 2,294 GNMA commercial mortgage-related securities 1,097,913 1,922 (25,942 ) 1,073,893 Other securities (debt and equity) 6,108 51 — 6,159 Total investment securities available for sale $ 5,368,259 $ 85,085 $ (56,532 ) $ 5,396,812 Investment securities held to maturity: Municipal securities $ 404,455 $ 9,444 $ (832 ) $ 413,067 Total investment securities held to maturity $ 404,455 $ 9,444 $ (832 ) $ 413,067 During the fourth quarter of 2015, the Corporation reclassified approximately $400 million of municipal securities and $125 million of mortgage-related securities from available for sale to held to maturity. The reclassification of these investment securities was accounted for at fair value. Management elected to transfer these investment securities as the Corporation has the positive intent and ability to hold these investment securities to maturity. The amortized cost and fair values of investment securities available for sale and held to maturity at December 31, 2015 , are shown below. Expected maturities will differ from contractual maturities because borrowers may have the right to call or prepay obligations with or without call or prepayment penalties. Available for Sale Held to Maturity ($ in Thousands) Amortized Cost Fair Value Amortized Cost Fair Value Due in one year or less $ 1,500 $ 1,515 $ 42,841 $ 26,761 Due after one year through five years 4,199 4,197 244,257 255,899 Due after five years through ten years — — 253,429 261,934 Due after ten years — — 503,240 515,637 Total debt securities 5,699 5,712 1,043,767 1,060,231 Residential mortgage-related securities: FNMA / FHLMC 1,388,995 1,414,626 41,469 41,337 GNMA 1,605,956 1,590,003 82,994 82,874 Private-label 1,722 1,709 — — GNMA commercial mortgage-related securities 1,982,477 1,955,310 — — Equity securities 18 54 — — Total investment securities $ 4,984,867 $ 4,967,414 $ 1,168,230 $ 1,184,442 Ratio of Fair Value to Amortized Cost 99.6 % 101.4 % During 2015, the Corporation restructured its investment securities portfolio and sold approximately $1.6 billion of FNMA and FHLMC mortgage-related securities and reinvested into GNMA mortgage-related securities, generating an $8 million net gain on sale. This restructuring lowered risk weighted assets and related capital requirements. Total proceeds and gross realized gains and losses from sales of investment securities for each of the three years ended December 31 were as follows. There were no other-than-temporary impairment write-downs on investment securities for 2015 , 2014 , or 2013 . 2015 2014 2013 ($ in Thousands) Gross gains $ 12,270 $ 1,184 $ 637 Gross losses (4,137 ) (690 ) (73 ) Investment securities gains, net $ 8,133 $ 494 $ 564 Proceeds from sales of investment securities $ 1,601,947 $ 102,011 $ 136,152 Pledged securities with a carrying value of approximately $3.2 billion and $2.8 billion at December 31, 2015 , and December 31, 2014 , respectively, were pledged to secure certain deposits or for other purposes as required or permitted by law. The following represents gross unrealized losses and the related fair value of investment securities available for sale and held to maturity, aggregated by investment category and length of time individual securities have been in a continuous unrealized loss position, at December 31, 2015 . Less than 12 months 12 months or more Total December 31, 2015 Number of Securities Unrealized Losses Fair Value Number of Securities Unrealized Losses Fair Value Unrealized Losses Fair Value ($ in Thousands) Investment securities available for sale: U.S. Treasury securities 1 $ (2 ) $ 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. In addition, with regards to its debt securities, the Corporation may also evaluate payment structure, whether there are defaulted payments or expected defaults, prepayment speeds, and the value of any underlying collateral. Based on the Corporation’s evaluation, management does not believe any unrealized loss at December 31, 2015 , 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. 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, 2014 . Less than 12 months 12 months or more Total December 31, 2014 Number Unrealized Fair Number Unrealized Fair Unrealized Fair ($ in Thousands) Investment securities available for sale: U.S. Treasury securities 1 $ (1 ) $ 998 — $ — $ — $ (1 ) $ 998 Municipal securities 6 (9 ) 3,374 6 (20 ) 2,133 (29 ) 5,507 Residential mortgage-related securities: FNMA / FHLMC 15 (1,395 ) 330,839 52 (29,028 ) 1,246,093 (30,423 ) 1,576,932 GNMA 1 (9 ) 2,874 4 (118 ) 10,440 (127 ) 13,314 Private-label 1 (9 ) 1,772 2 (1 ) 27 (10 ) 1,799 GNMA commercial mortgage-related securities 9 (1,766 ) 329,982 20 (24,176 ) 460,425 (25,942 ) 790,407 Total 33 $ (3,189 ) $ 669,839 84 $ (53,343 ) $ 1,719,118 $ (56,532 ) $ 2,388,957 Investment securities held to maturity: Municipal securities 74 $ (216 ) $ 31,924 85 $ (616 ) $ 38,915 $ (832 ) $ 70,839 Total 74 $ (216 ) $ 31,924 85 $ (616 ) $ 38,915 $ (832 ) $ 70,839 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, 2015 , and 2014 , the Corporation had FHLB stock of $74 million and $118 million , respectively, reflecting the overall reduction in FHLB short-term and long-term funding. The Corporation had Federal Reserve Bank stock of $73 million and $71 million at December 31, 2015 and 2014 , respectively.

Loans

Loans	12 Months Ended
	Dec. 31, 2015
Receivables [Abstract]
Loans	NOTE 4 LOANS: During 2015, the Corporation reclassified all closed end first lien home equity loans to residential mortgage loans in order to better align with the Corporation's regulatory reporting of residential mortgage loan products. All prior periods have been restated to reflect this change. As a result, the restated home equity loan portfolio is $1.1 billion for December 31, 2014, compared to the originally reported amount of $1.6 billion . Similarly, the restated residential mortgage loan portfolio is $5.1 billion for December 31, 2014, compared to the originally reported amount of $4.5 billion . Loans at December 31 are summarized below. 2015 2014 ($ in Thousands) Commercial and industrial $ 6,147,440 $ 5,905,902 Commercial real estate — owner occupied 918,212 1,007,937 Lease financing 43,243 51,529 Commercial and business lending 7,108,895 6,965,368 Commercial real estate — investor 3,234,266 3,056,485 Real estate construction 1,162,145 1,008,956 Commercial real estate lending 4,396,411 4,065,441 Total commercial 11,505,306 11,030,809 Home equity 1,005,802 1,051,927 Installment and credit cards 419,968 454,219 Residential mortgage 5,783,267 5,056,891 Total consumer 7,209,037 6,563,037 Total loans $ 18,714,343 $ 17,593,846 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. 2015 ($ in Thousands) Balance at beginning of year $ 74,420 New loans 14,840 Repayments (19,990 ) Changes due to status of executive officers and directors (32,673 ) Balance at end of year $ 36,597 A summary of the changes in the allowance for credit losses for the years indicated was as follows. 2015 2014 2013 ($ in Thousands) Allowance for Loan Losses: Balance at beginning of year $ 266,302 $ 268,315 $ 297,409 Provision for loan losses 38,000 13,000 10,000 Charge offs (52,280 ) (44,096 ) (88,061 ) Recoveries 22,242 29,083 48,967 Net charge offs (30,038 ) (15,013 ) (39,094 ) Balance at end of year $ 274,264 $ 266,302 $ 268,315 Allowance for Unfunded Commitments: Balance at beginning of year $ 24,900 $ 21,900 $ 21,800 Provision for unfunded commitments (500 ) 3,000 100 Balance at end of year $ 24,400 $ 24,900 $ 21,900 Allowance for Credit Losses $ 298,664 $ 291,202 $ 290,215 The allowance for credit losses is comprised of the allowance for loan losses and the allowance for unfunded commitments. The level of the allowance for loan losses represents management’s estimate of an amount appropriate to provide for probable credit losses in the loan portfolio at the balance sheet date. The allowance for unfunded commitments is maintained at a level believed by management to be sufficient to absorb estimated probable losses related to unfunded credit facilities (including unfunded loan commitments and letters of credit) and is included in accrued expenses and other liabilities on the consolidated balance sheets. See Note 1 for the Corporation’s accounting policy for the allowance for loan losses and the allowance for unfunded commitments. See Note 16 for additional information on the allowance for unfunded commitments. 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 Lease financing Commercial real estate — investor Real estate construction Home equity Installment and credit cards Residential mortgage Total Balance at Dec 31, 2014 $ 116,025 $ 16,510 $ 1,610 $ 46,333 $ 20,999 $ 26,464 $ 6,435 $ 31,926 $ 266,302 Provision for loan losses 30,861 3,894 (671 ) (2,827 ) 2,749 906 2,194 894 38,000 Charge offs (27,687 ) (2,645 ) — (4,645 ) (750 ) (7,048 ) (3,869 ) (5,636 ) (52,280 ) Recoveries 9,795 921 26 4,157 2,268 3,233 765 1,077 22,242 Balance at Dec 31, 2015 $ 128,994 $ 18,680 $ 965 $ 43,018 $ 25,266 $ 23,555 $ 5,525 $ 28,261 $ 274,264 Allowance for loan losses: Ending balance impaired loans individually evaluated for impairment $ 7,522 $ — $ — $ 229 $ — $ 46 $ — $ 166 $ 7,963 Ending balance impaired loans collectively evaluated for impairment $ 640 $ 448 $ — $ 1,602 $ 453 $ 10,072 $ 195 $ 12,296 $ 25,706 Total impaired loans $ 8,162 $ 448 $ — $ 1,831 $ 453 $ 10,118 $ 195 $ 12,462 $ 33,669 Ending balance all other loans collectively evaluated for impairment $ 120,832 $ 18,232 $ 965 $ 41,187 $ 24,813 $ 13,437 $ 5,330 $ 15,799 $ 240,595 Total $ 128,994 $ 18,680 $ 965 $ 43,018 $ 25,266 $ 23,555 $ 5,525 $ 28,261 $ 274,264 Loans: Ending balance impaired loans individually evaluated for impairment $ 89,935 $ 6,221 $ 1,634 $ 5,460 $ — $ 1,281 $ — $ 6,956 $ 111,487 Ending balance impaired loans collectively evaluated for impairment $ 31,299 $ 9,705 $ — $ 25,098 $ 1,450 $ 21,032 $ 1,154 $ 64,396 $ 154,134 Total impaired loans $ 121,234 $ 15,926 $ 1,634 $ 30,558 $ 1,450 $ 22,313 $ 1,154 $ 71,352 $ 265,621 Ending balance all other loans collectively evaluated for impairment $ 6,026,206 $ 902,286 $ 41,609 $ 3,203,708 $ 1,160,695 $ 983,489 $ 418,814 $ 5,711,915 $ 18,448,722 Total $ 6,147,440 $ 918,212 $ 43,243 $ 3,234,266 $ 1,162,145 $ 1,005,802 $ 419,968 $ 5,783,267 $ 18,714,343 At December 31, 2015 , $42 million of the commercial and industrial allowance for loan losses was attributable to Oil and Gas related credits, compared to $17 million at December 31, 2014. This allocated allowance for loan losses represented 5.58% and 2.26% of period end Oil and Gas related loans at December 31, 2015 and December 31, 2014, respectively. The total allowance for loan losses is available to absorb losses from any segment of the loan portfolio. For comparison purposes, a summary of the changes in the allowance for loan losses by portfolio segment for the year ended December 31, 2014 , was as follows. $ in Thousands Commercial and industrial Commercial real estate — owner occupied Lease financing Commercial real estate — investor Real estate construction Home equity Installment and credit cards Residential mortgage Total Balance at Dec 31, 2013 $ 104,501 $ 19,476 $ 1,607 $ 58,156 $ 23,418 $ 27,932 $ 2,416 $ 30,809 $ 268,315 Provision for loan losses 14,767 (1,296 ) 35 (17,290 ) (1,277 ) 6,278 6,279 5,504 13,000 Charge offs (14,633 ) (3,476 ) (39 ) (4,529 ) (1,958 ) (10,946 ) (2,876 ) (5,639 ) (44,096 ) Recoveries 11,390 1,806 7 9,996 816 3,200 616 1,252 29,083 Balance at Dec 31, 2014 $ 116,025 $ 16,510 $ 1,610 $ 46,333 $ 20,999 $ 26,464 $ 6,435 $ 31,926 $ 266,302 Allowance for loan losses: Ending balance impaired loans individually evaluated for impairment $ 13,615 $ 1,490 $ 574 $ 1,649 $ 328 $ 11 $ — $ 199 $ 17,866 Ending balance impaired loans collectively evaluated for impairment $ 2,852 $ 1,731 $ — $ 1,938 $ 767 $ 11,371 $ 308 $ 13,598 $ 32,565 Total impaired loans $ 16,467 $ 3,221 $ 574 $ 3,587 $ 1,095 $ 11,382 $ 308 $ 13,797 $ 50,431 Ending balance all other loans collectively evaluated for impairment $ 99,558 $ 13,289 $ 1,036 $ 42,746 $ 19,904 $ 15,082 $ 6,127 $ 18,129 $ 215,871 Total $ 116,025 $ 16,510 $ 1,610 $ 46,333 $ 20,999 $ 26,464 $ 6,435 $ 31,926 $ 266,302 Loans: Ending balance impaired loans individually evaluated for impairment $ 45,118 $ 20,731 $ 1,801 $ 19,683 $ 3,776 $ 962 $ — $ 9,751 $ 101,822 Ending balance impaired loans collectively evaluated for impairment $ 38,437 $ 15,548 $ — $ 26,129 $ 2,350 $ 23,698 $ 1,587 $ 66,058 $ 173,807 Total impaired loans $ 83,555 $ 36,279 $ 1,801 $ 45,812 $ 6,126 $ 24,660 $ 1,587 $ 75,809 $ 275,629 Ending balance all other loans collectively evaluated for impairment $ 5,822,347 $ 971,658 $ 49,728 $ 3,010,673 $ 1,002,830 $ 1,027,267 $ 452,632 $ 4,981,082 $ 17,318,217 Total $ 5,905,902 $ 1,007,937 $ 51,529 $ 3,056,485 $ 1,008,956 $ 1,051,927 $ 454,219 $ 5,056,891 $ 17,593,846 The following table presents commercial loans by credit quality indicator at December 31, 2015 . Pass Special Mention Potential Problem Impaired Total ($ Thousands) Commercial and industrial $ 5,455,573 $ 339,953 $ 230,680 $ 121,234 $ 6,147,440 Commercial real estate — owner occupied 827,694 38,886 35,706 15,926 918,212 Lease financing 37,969 1,190 2,450 1,634 43,243 Commercial and business lending 6,321,236 380,029 268,836 138,794 7,108,895 Commercial real estate — investor 3,150,134 27,630 25,944 30,558 3,234,266 Real estate construction 1,156,524 252 3,919 1,450 1,162,145 Commercial real estate lending 4,306,658 27,882 29,863 32,008 4,396,411 Total commercial $ 10,627,894 $ 407,911 $ 298,699 $ 170,802 $ 11,505,306 The following table presents commercial loans by credit quality indicator at December 31, 2014 . Pass Special Mention Potential Problem Impaired Total ($ Thousands) Commercial and industrial $ 5,594,497 $ 119,328 $ 108,522 $ 83,555 $ 5,905,902 Commercial real estate — owner occupied 904,526 18,437 48,695 36,279 1,007,937 Lease financing 46,931 88 2,709 1,801 51,529 Commercial and business lending 6,545,954 137,853 159,926 121,635 6,965,368 Commercial real estate — investor 2,974,493 12,137 24,043 45,812 3,056,485 Real estate construction 998,972 2,082 1,776 6,126 1,008,956 Commercial real estate lending 3,973,465 14,219 25,819 51,938 4,065,441 Total commercial $ 10,519,419 $ 152,072 $ 185,745 $ 173,573 $ 11,030,809 The following table presents consumer loans by credit quality indicator at December 31, 2015 . Performing 30-89 Days Past Due Potential Problem Impaired Total ($ Thousands) Home equity $ 975,348 $ 7,919 $ 222 $ 22,313 $ 1,005,802 Installment and credit cards 416,944 1,870 — 1,154 419,968 Residential mortgage 5,704,189 4,930 2,796 71,352 5,783,267 Total consumer $ 7,096,481 $ 14,719 $ 3,018 $ 94,819 $ 7,209,037 The following table presents consumer loans by credit quality indicator at December 31, 2014 . Performing 30-89 Days Past Due Potential Problem Impaired Total ($ Thousands) Home equity $ 1,017,604 $ 8,783 $ 880 $ 24,660 $ 1,051,927 Installment and credit cards 450,698 1,932 2 1,587 454,219 Residential mortgage 4,972,455 4,846 3,781 75,809 5,056,891 Total consumer $ 6,440,757 $ 15,561 $ 4,663 $ 102,056 $ 6,563,037 Factors that are important to managing overall credit quality are sound loan underwriting and administration, systematic monitoring of existing loans and commitments, effective loan review on an ongoing basis, early identification of potential problems, and appropriate allowance for loan losses, allowance for unfunded commitments, nonaccrual, and charge off policies. For commercial loans, management has determined the pass credit quality indicator to include credits that exhibit acceptable financial statements, cash flow, and leverage. If any risk exists, it is mitigated by the loan structure, collateral, monitoring, or control. For consumer loans, performing loans include credits that are performing in accordance with the original contractual terms. Loans are considered past due if the required principal and interest payments have not been received as of the date such payments were due. Special mention credits have potential weaknesses that deserve management’s attention. If left uncorrected, these potential weaknesses may result in deterioration of the repayment prospects for the credit. Potential problem loans are considered inadequately protected by the current net worth and paying capacity of the obligor or the collateral pledged. These loans generally have a well-defined weakness, or weaknesses, that may jeopardize liquidation of the debt and are characterized by the distinct possibility that the Corporation will sustain some loss if the deficiencies are not corrected. Lastly, management considers a loan to be impaired when it is probable that the Corporation will be unable to collect all amounts due according to the original contractual terms of the note agreement, including both principal and interest. Management has determined that commercial and consumer loan relationships that have nonaccrual status or have had their terms restructured in a troubled debt restructuring meet this impaired loan definition. Commercial loans classified as special mention, potential problem, and impaired are reviewed at a minimum on a quarterly basis, while pass and performing rated credits are reviewed on an annual basis or more frequently if the loan renewal is less than one year or if otherwise warranted. See Note 1 for the Corporation’s accounting policy for loans. The following table presents loans by past due status at December 31, 2015 . 30-59 Days Past Due 60-89 Days Past Due 90 Days or More Past Due* Total Past Due Current Total ($ in Thousands) Accruing loans Commercial and industrial $ 602 $ 409 $ 249 $ 1,260 $ 6,054,239 $ 6,055,499 Commercial real estate — owner occupied 7,142 — — 7,142 903,021 910,163 Lease financing — — — — 41,609 41,609 Commercial and business lending 7,744 409 249 8,402 6,998,869 7,007,271 Commercial real estate — investor 291 — — 291 3,225,332 3,225,623 Real estate construction 270 26 — 296 1,160,909 1,161,205 Commercial real estate lending 561 26 — 587 4,386,241 4,386,828 Total commercial 8,305 435 249 8,989 11,385,110 11,394,099 Home equity 6,190 1,729 — 7,919 982,639 990,558 Installment and credit cards 1,195 675 1,399 3,269 416,374 419,643 Residential mortgage 4,491 439 — 4,930 5,726,855 5,731,785 Total consumer 11,876 2,843 1,399 16,118 7,125,868 7,141,986 Total accruing loans $ 20,181 $ 3,278 $ 1,648 $ 25,107 $ 18,510,978 $ 18,536,085 Nonaccrual loans Commercial and industrial $ 895 $ 16 $ 4,848 $ 5,759 $ 86,182 $ 91,941 Commercial real estate — owner occupied — 2,572 1,301 3,873 4,176 8,049 Lease financing — — — — 1,634 1,634 Commercial and business lending 895 2,588 6,149 9,632 91,992 101,624 Commercial real estate — investor 3,174 1,158 3,480 7,812 831 8,643 Real estate construction 133 61 427 621 319 940 Commercial real estate lending 3,307 1,219 3,907 8,433 1,150 9,583 Total commercial 4,202 3,807 10,056 18,065 93,142 111,207 Home equity 1,922 1,330 5,833 9,085 6,159 15,244 Installment and credit cards 47 39 151 237 88 325 Residential mortgage 3,984 5,251 17,950 27,185 24,297 51,482 Total consumer 5,953 6,620 23,934 36,507 30,544 67,051 Total nonaccrual loans** $ 10,155 $ 10,427 $ 33,990 $ 54,572 $ 123,686 $ 178,258 Total loans Commercial and industrial $ 1,497 $ 425 $ 5,097 $ 7,019 $ 6,140,421 $ 6,147,440 Commercial real estate — owner occupied 7,142 2,572 1,301 11,015 907,197 918,212 Lease financing — — — — 43,243 43,243 Commercial and business lending 8,639 2,997 6,398 18,034 7,090,861 7,108,895 Commercial real estate — investor 3,465 1,158 3,480 8,103 3,226,163 3,234,266 Real estate construction 403 87 427 917 1,161,228 1,162,145 Commercial real estate lending 3,868 1,245 3,907 9,020 4,387,391 4,396,411 Total commercial 12,507 4,242 10,305 27,054 11,478,252 11,505,306 Home equity 8,112 3,059 5,833 17,004 988,798 1,005,802 Installment and credit cards 1,242 714 1,550 3,506 416,462 419,968 Residential mortgage 8,475 5,690 17,950 32,115 5,751,152 5,783,267 Total consumer 17,829 9,463 25,333 52,625 7,156,412 7,209,037 Total loans $ 30,336 $ 13,705 $ 35,638 $ 79,679 $ 18,634,664 $ 18,714,343 * The recorded investment in loans past due 90 days or more and still accruing totaled $2 million at December 31, 2015 (the same as the reported balances for the accruing loans noted above). ** The percent of nonaccrual loans which are current was 69% at December 31, 2015 . The following table presents loans by past due status at December 31, 2014 . 30-59 Days Past Due 60-89 Days Past Due 90 Days or More Past Due* Total Past Due Current Total ($ in Thousands) Accruing loans Commercial and industrial $ 4,466 $ 10,281 $ 254 $ 15,001 $ 5,841,238 $ 5,856,239 Commercial real estate — owner occupied 8,429 2,199 — 10,628 971,484 982,112 Lease financing — — — — 49,728 49,728 Commercial and business lending 12,895 12,480 254 25,629 6,862,450 6,888,079 Commercial real estate — investor 712 496 — 1,208 3,032,592 3,033,800 Real estate construction 951 33 — 984 1,002,573 1,003,557 Commercial real estate lending 1,663 529 — 2,192 4,035,165 4,037,357 Total commercial 14,558 13,009 254 27,821 10,897,615 10,925,436 Home equity 6,988 1,795 52 8,835 1,026,641 1,035,476 Installment and credit cards 1,186 746 1,317 3,249 450,357 453,606 Residential mortgage 3,889 957 — 4,846 4,997,069 5,001,915 Total consumer 12,063 3,498 1,369 16,930 6,474,067 6,490,997 Total accruing loans $ 26,621 $ 16,507 $ 1,623 $ 44,751 $ 17,371,682 $ 17,416,433 Nonaccrual loans Commercial and industrial $ 872 $ 627 $ 10,154 $ 11,653 $ 38,010 $ 49,663 Commercial real estate — owner occupied 3,197 41 8,596 11,834 13,991 25,825 Lease financing — — 513 513 1,288 1,801 Commercial and business lending 4,069 668 19,263 24,000 53,289 77,289 Commercial real estate — investor 1,857 459 12,765 15,081 7,604 22,685 Real estate construction 87 73 798 958 4,441 5,399 Commercial real estate lending 1,944 532 13,563 16,039 12,045 28,084 Total commercial 6,013 1,200 32,826 40,039 65,334 105,373 Home equity 1,471 1,766 6,840 10,077 6,374 16,451 Installment and credit cards 96 39 141 276 337 613 Residential mortgage 5,172 3,193 23,492 31,857 23,119 54,976 Total consumer 6,739 4,998 30,473 42,210 29,830 72,040 Total nonaccrual loans** $ 12,752 $ 6,198 $ 63,299 $ 82,249 $ 95,164 $ 177,413 Total loans Commercial and industrial $ 5,338 $ 10,908 $ 10,408 $ 26,654 $ 5,879,248 $ 5,905,902 Commercial real estate — owner occupied 11,626 2,240 8,596 22,462 985,475 1,007,937 Lease financing — — 513 513 51,016 51,529 Commercial and business lending 16,964 13,148 19,517 49,629 6,915,739 6,965,368 Commercial real estate — investor 2,569 955 12,765 16,289 3,040,196 3,056,485 Real estate construction 1,038 106 798 1,942 1,007,014 1,008,956 Commercial real estate lending 3,607 1,061 13,563 18,231 4,047,210 4,065,441 Total commercial 20,571 14,209 33,080 67,860 10,962,949 11,030,809 Home equity 8,459 3,561 6,892 18,912 1,033,015 1,051,927 Installment and credit cards 1,282 785 1,458 3,525 450,694 454,219 Residential mortgage 9,061 4,150 23,492 36,703 5,020,188 5,056,891 Total consumer 18,802 8,496 31,842 59,140 6,503,897 6,563,037 Total loans $ 39,373 $ 22,705 $ 64,922 $ 127,000 $ 17,466,846 $ 17,593,846 * The recorded investment in loans past due 90 days or more and still accruing totaled $2 million at December 31, 2014 (the same as the reported balances for the accruing loans noted above). ** The percent of nonaccrual loans which are current was 54% at December 31, 2014 . The following table presents impaired loans at December 31, 2015 . Recorded Investment Unpaid Principal Balance Related Allowance Average Recorded Investment Interest Income Recognized* ($ 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 Lease financing — — — — — 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 Home equity 21,769 23,989 10,118 22,624 1,147 Installment and credit cards 1,154 1,225 195 1,199 30 Residential mortgage 66,590 71,084 12,462 68,183 2,374 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 $ 63,449 $ 70,625 $ — $ 77,666 $ 1,657 Commercial real estate — owner occupied 6,221 6,648 — 6,534 15 Lease financing 1,634 1,634 — 1,907 — 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 Home equity 544 544 — 544 30 Installment and credit cards — — — — — Residential mortgage 4,762 5,033 — 4,726 126 Total consumer 5,306 5,577 — 5,270 156 Total loans $ 79,346 $ 87,324 $ — $ 94,140 $ 1,918 Total Commercial and industrial $ 121,234 $ 130,034 $ 8,162 $ 124,499 $ 2,512 Commercial real estate — owner occupied 15,926 16,452 448 16,621 427 Lease financing 1,634 1,634 — 1,907 — 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 Home equity 22,313 24,533 10,118 23,168 1,177 Installment and credit cards 1,154 1,225 195 1,199 30 Residential mortgage 71,352 76,117 12,462 72,909 2,500 Total consumer 94,819 101,875 22,775 97,276 3,707 Total loans** $ 265,621 $ 284,433 $ 33,669 $ 273,011 $ 8,716 * Interest income recognized included $4 million of interest income recognized on accruing restructured loans for the year ended December 31, 2015 . ** The net recorded investment (defined as recorded investment, net of the related allowance) of the impaired loans represented 82% of the unpaid principal balance at December 31, 2015. The following table presents impaired loans at December 31, 2014 . Recorded Investment Unpaid Principal Balance Related Allowance Average Recorded Investment Interest Income Recognized* ($ in Thousands) Loans with a related allowance Commercial and industrial $ 76,433 $ 80,414 $ 16,467 $ 80,004 $ 3,139 Commercial real estate — owner occupied 19,839 21,807 3,221 20,878 681 Lease financing 1,801 1,801 574 2,009 — Commercial and business lending 98,073 104,022 20,262 102,891 3,820 Commercial real estate — investor 36,841 40,869 3,587 38,657 1,250 Real estate construction 3,043 5,910 1,095 3,818 105 Commercial real estate lending 39,884 46,779 4,682 42,475 1,355 Total commercial 137,957 150,801 24,944 145,366 5,175 Home equity 23,874 26,585 11,382 25,087 1,257 Installment and credit cards 1,587 1,795 308 1,736 58 Residential mortgage 68,748 74,005 13,797 70,030 2,307 Total consumer 94,209 102,385 25,487 96,853 3,622 Total loans $ 232,166 $ 253,186 $ 50,431 $ 242,219 $ 8,797 Loans with no related allowance Commercial and industrial $ 7,122 $ 12,634 $ — $ 8,851 $ 82 Commercial real estate — owner occupied 16,440 19,019 — 17,970 219 Commercial and business lending 23,562 31,653 — 26,821 301 Commercial real estate — investor 8,971 14,036 — 10,014 133 Real estate construction 3,083 3,815 — 3,241 — Commercial real estate lending 12,054 17,851 — 13,255 133 Total commercial 35,616 49,504 — 40,076 434 Home equity 786 806 — 851 18 Installment and credit cards — — — — — Residential mortgage 7,061 7,315 — 7,224 135 Total consumer 7,847 8,121 — 8,075 153 Total loans $ 43,463 $ 57,625 $ — $ 48,151 $ 587 Total Commercial and industrial $ 83,555 $ 93,048 $ 16,467 $ 88,855 $ 3,221 Commercial real estate — owner occupied 36,279 40,826 3,221 38,848 900 Lease financing 1,801 1,801 574 2,009 — Commercial and business lending 121,635 135,675 20,262 129,712 4,121 Commercial real estate — investor 45,812 54,905 3,587 48,671 1,383 Real estate construction 6,126 9,725 1,095 7,059 105 Commercial real estate lending 51,938 64,630 4,682 55,730 1,488 Total commercial 173,573 200,305 24,944 185,442 5,609 Home equity 24,660 27,391 11,382 25,938 1,275 Installment and credit cards 1,587 1,795 308 1,736 58 Residential mortgage 75,809 81,320 13,797 77,254 2,442 Total consumer 102,056 110,506 25,487 104,928 3,775 Total loans** $ 275,629 $ 310,811 $ 50,431 $ 290,370 $ 9,384 * Interest income recognized included $5 million of interest income recognized on accruing restructured loans for the year ended December 31, 2014 . ** The net recorded investment (defined as recorded investment, net of the related allowance) of the impaired loans represented 72% of of the unpaid principal balance at December 31, 2014. 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, 2015 , there was approximately $7 million of commitments to lend additional funds to borrowers with restructured loans. The following table presents nonaccrual and performing restructured loans by loan portfolio. December 31, 2015 December 31, 2014 December 31, 2013 Performing Restructured Loans Nonaccrual Restructured Loans* Performing Restructured Loans Nonaccrual Restructured Loans* Performing Restructured Loans Nonaccrual Restructured Loans* ($ in Thousands) Commercial and industrial $ 29,293 $ 1,714 $ 33,892 $ 3,260 $ 32,517 $ 6,900 Commercial real estate — owner occupied 7,877 2,703 10,454 5,656 13,009 10,999 Commercial real estate — investor 21,915 3,936 23,127 15,216 44,946 18,069 Real estate construction 510 177 727 2,438 3,793 2,065 Home equity 7,069 4,522 8,209 4,838 8,197 4,441 Installment and credit cards 829 40 974 199 246 451 Residential mortgage 19,870 24,592 20,833 26,049 21,277 16,660 $ 87,363 $ 37,684 $ 98,216 $ 57,656 $ 123,985 $ 59,585 * 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, 2015 , 2014 and 2013 , respectively, and the recorded investment and unpaid principal balance as of December 31, 2015 , 2014 and 2013 , respectively. Year Ended December 31, 2015 Year Ended December 31, 2014 Year Ended December 31, 2013 Number of Loans Recorded Investment(1) Unpaid Principal Balance(2) Number of Loans Recorded Investment(1) Unpaid Principal Balance(2) Number of Loans Recorded Investment(1) Unpaid Principal Balance(2) ($ in Thousands) Commercial and industrial 12 $ 2,219 $ 2,900 15 $ 7,681 $ 7,711 48 $ 11,833 $ 14,543 Commercial real estate — owner occupied 5 3,694 3,901 4 1,465 1,625 12 8,823 9,035 Commercial real estate — investor 5 21,573 21,640 6 6,097 6,521 25 26,480 28,516 Real estate construction 4 78 79 2 15 15 9 1,822 1,961 Home equity 88 3,103 3,249 117 3,913 4,308 82 3,991 4,242 Installment and credit cards — — — 2 24 26 3 193 200 Residential mortgage 97 10,464 10,996 163 19,675 20,454 99 10,910 12,822 211 $ 41,131 $ 42,765 309 $ 38,870 $ 40,660 278 $ 64,052 $ 71,319 (1) Represents post-modification outstanding recorded investment. (2) 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, 2015 , restructured loan modifications of commercial and industrial, commercial real estate, and real estate construction loans primarily included maturity date extensions and payment schedule modifications. Restructured loan modifications of home equity and residential mortgage loans primarily included maturity date extensions, interest rate concessions, payment schedule modifications, non-reaffirmed Chapter 7 bankruptcies, or a combination of these concessions for the year ended December 31, 2015 . The following table provides the number of loans modified in a troubled debt restructuring during the previous 12 months which subsequently defaulted during the years ended December 31, 2015 , 2014 , and 2013 , respectively, as well as the recorded investment in these restructured loans as of December 31, 2015 , 2014 , and 2013 , respectively. Year Ended December 31, 2015 Year Ended December 31, 2014 Year Ended December 31, 2013 Number of Loans Recorded Investment Number of Loans Recorded Investment Number of Loans Recorded Investment ($ in Thousands) Commercial and industrial 2 $ 197 1 $ 52 15 $ 1,493 Commercial real estate — owner occupied — — 3 785 4 542 Commercial real estate — investor — — 13 6,200 4 1,784 Real estate construction — — 1 160 4 80 Home equity 28 1,220 54 1,802 11 829 Installment and credit cards — — 3 34 — — Residential mortgage 61 6,815 80 10,032 26 4,528 91 $ 8,232 155 $ 19,065 64 $ 9,256 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.

Goodwill and Intangible Assets

Goodwill and Intangible Assets	12 Months Ended
	Dec. 31, 2015
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Intangible Assets	NOTE 5 GOODWILL AND 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 2015, 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 2015 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 2015 impairment testing that have changed the Corporation's impairment assessment conclusion. There were no impairment charges recorded in 2015, 2014, or 2013. At December 31, 2015 , the Corporation had goodwill of $969 million , compared to $929 million at December 31, 2014. There was an addition to the carrying amount of goodwill of approximately $40 million for the Ahmann & Martin Co. acquisition that occurred during the quarter ended March 31, 2015. See Note 2 for additional information on the Ahmann & Martin Co. acquisition. 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. There was an addition to the gross carrying amount of other intangibles of approximately $12 million for the customer relationships acquired with the Ahmann & Martin Co. acquisition that occurred during the quarter ended March 31, 2015. See Note 2 for additional information on the Ahmann & Martin Co. acquisition. For core deposit intangibles and other intangibles, changes in the gross carrying amount, accumulated amortization, and net book value were as follows. 2015 2014 2013 ($ in Thousands) Core deposit intangibles: Gross carrying amount $ 19,545 $ 36,230 $ 36,230 Accumulated amortization (19,152 ) (34,433 ) (31,565 ) Net book value $ 393 $ 1,797 $ 4,665 Amortization during the year $ 1,404 $ 2,868 $ 3,122 Other intangibles: Gross carrying amount $ 31,398 $ 19,283 $ 19,283 Accumulated amortization (15,333 ) (13,643 ) (12,764 ) Net book value $ 16,065 $ 5,640 $ 6,519 Additions during the period $ 12,115 $ — $ — Amortization during the year $ 1,690 $ 879 $ 921 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. 2015 2014 2013 ($ in Thousands) Mortgage servicing rights Mortgage servicing rights at beginning of year $ 61,379 $ 64,193 $ 61,425 Additions 12,372 8,253 18,256 Amortization (11,601 ) (11,067 ) (15,488 ) Mortgage servicing rights at end of year $ 62,150 $ 61,379 $ 64,193 Valuation allowance at beginning of year (1,234 ) (913 ) (15,476 ) (Additions) recoveries, net 425 (321 ) 14,563 Valuation allowance at end of year (809 ) (1,234 ) (913 ) Mortgage servicing rights, net $ 61,341 $ 60,145 $ 63,280 Fair value of mortgage servicing rights $ 70,686 $ 66,342 $ 74,444 Portfolio of residential mortgage loans serviced for others (“servicing portfolio”) $ 7,915,224 $ 7,999,294 $ 8,084,000 Mortgage servicing rights, net to servicing portfolio 0.77 % 0.75 % 0.78 % Mortgage servicing rights expense (1) $ 11,176 $ 11,388 $ 925 (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, 2015 . 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, 2016 $ 281 $ 1,735 $ 10,109 2017 112 1,702 8,415 2018 — 1,672 7,010 2019 — 1,373 5,894 2020 — 1,256 4,978 Beyond 2020 — 8,327 25,744 Total Estimated Amortization Expense $ 393 $ 16,065 $ 62,150

Premises and Equipment

Premises and Equipment	12 Months Ended
	Dec. 31, 2015
Property, Plant and Equipment [Abstract]
Premises and Equipment	NOTE 6 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. 2015 2014 Estimated Useful Lives Cost Accumulated Depreciation Net Book Value Net Book Value ($ in Thousands) Land — $ 52,104 $ — $ 52,104 $ 52,790 Land improvements 3 – 15 years 11,570 4,909 6,661 6,608 Buildings 5 – 39 years 261,418 119,986 141,432 139,702 Computers 3 – 5 years 37,875 31,503 6,372 7,518 Furniture, fixtures and other equipment 3 – 15 years 159,094 109,300 49,794 55,747 Leasehold improvements 3 – 15 years 31,769 20,526 11,243 12,323 Total premises and equipment $ 553,830 $ 286,224 $ 267,606 $ 274,688 Depreciation and amortization of premises and equipment totaled $33 million in 2015 , $34 million in 2014 , and $33 million in 2013 . The Corporation and certain subsidiaries are obligated under noncancelable operating leases for other facilities and equipment, certain of which provide for increased rentals based upon increases in cost of living adjustments and other operating costs. The approximate minimum annual rentals and commitments under these noncancelable agreements and leases with remaining terms in excess of one year are as follows. ($ in Thousands) 2016 $ 10,417 2017 9,957 2018 8,678 2019 8,348 2020 7,583 Thereafter 17,968 Total $ 62,951 Total rental expense under leases, net of sublease income, totaled $13 million in 2015 , $11 million in 2014 , and $13 million in 2013 , respectively.

Deposits

Deposits	12 Months Ended
	Dec. 31, 2015
Deposits [Abstract]
Deposits	NOTE 7 DEPOSITS: The distribution of deposits at December 31 was as follows. 2015 2014 ($ in Thousands) Noninterest-bearing demand deposits $ 5,562,466 $ 4,505,272 Savings deposits 1,334,420 1,235,277 Interest-bearing demand deposits 3,445,000 3,126,854 Money market deposits 9,102,977 8,324,646 Brokered certificates of deposit 42,443 42,556 Other time deposits 1,520,359 1,528,899 Total deposits $ 21,007,665 $ 18,763,504 Time deposits of $100,000 or more were $466 million and $457 million at December 31, 2015 and 2014 , respectively. Time deposits of $250,000 or more were $127 million and $152 million at December 31, 2015 and 2014 , respectively. Aggregate annual maturities of all time deposits at December 31, 2015 , are as follows. Maturities During Year Ending December 31, ($ in Thousands) 2016 $ 885,249 2017 161,528 2018 238,184 2019 151,161 2020 123,022 Thereafter 3,658 Total $ 1,562,802

Short-term Funding

Short-term Funding	12 Months Ended
	Dec. 31, 2015
Short-term Debt [Abstract]
Short-term Funding	NOTE 8 SHORT-TERM FUNDING: Short-term funding at December 31 was as follows. 2015 2014 ($ in Thousands) Federal funds purchased $ 47,870 $ 109,770 Securities sold under agreements to repurchase 383,568 384,221 Federal funds purchased and securities sold under agreements to repurchase 431,438 493,991 FHLB advances 335,000 500,000 Commercial paper 67,978 74,297 Other short-term funding 402,978 574,297 Total short-term funding $ 834,416 $ 1,068,288 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, 2015, the Corporation pledged GSE mortgage-related securities with a fair value of $474 million as collateral for the repurchase agreements. Securities pledged as collateral under repurchase agreements are maintained with the Corporation's safekeeping agents and are monitored on a daily basis due to the market risk of fair value changes in the underlying securities. The Corporation generally pledges excess securities to ensure there is sufficient collateral to satisfy short-term fluctuations in both the repurchase agreement balances and the fair value of the underlying securities. The remaining contractual maturity of the securities sold under agreements to repurchase in the consolidated balance sheets as of December 31, 2015 is presented in the following table. Remaining Contractual Maturity of the Agreements December 31, 2015 Overnight and Continuous Up to 30 days 30-90 days Greater than 90 days Total ($ in Thousands) Repurchase agreements GSE securities $ 383,568 $ — $ — $ — $ 383,568 Total $ 383,568 $ — $ — $ — $ 383,568 Gross amounts of recognized liabilities for repurchase agreements $ 383,568

Long-term Funding

Long-term Funding	12 Months Ended
	Dec. 31, 2015
Debt Disclosure [Abstract]
Long-term Funding	NOTE 9 LONG-TERM FUNDING: The components of long-term funding (funding with original contractual maturities greater than one year) at December 31 were as follows. 2015 2014 ($ in Thousands) FHLB advances $ 1,750,225 $ 3,000,260 Senior notes, at par 680,000 680,000 Subordinated notes, at par 250,000 250,000 Other long-term funding and capitalized costs (875 ) (143 ) Total long-term funding $ 2,679,350 $ 3,930,117 FHLB advances: At December 31, 2015 , the long-term FHLB advances had a weighted average interest rate of 0.24% , compared to 0.11% at December 31, 2014 . The 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. These notes have been called for redemption. 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, 2015, the Corporation had $5.5 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, 2015, was $2.1 billion . The table below summarizes the maturities of the Corporation’s long-term funding at December 31, 2015 . Year ($ in Thousands) 2016 $ 430,317 2017 27 2018 1,500,000 2019 499,617 2020 172 Thereafter 249,217 Total long-term funding $ 2,679,350

Stockholders' Equity

Stockholders' Equity	12 Months Ended
	Dec. 31, 2015
Equity [Abstract]
Stockholders' Equity	NOTE 10 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 are 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 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 B Preferred Stock have been declared for that period, and sufficient funds have been set aside to make payment. The Series B 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, 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 does 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 , while during 2014 the Corporation repurchased approximately 88,000 depositary shares for $2 million . As of December 31, 2015, approximately $5 million remained available under this repurchase authorization. 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, 2015 , $10 million remained available under this repurchase authorization. See Part II, Item 5, “Market for Registrant’s Common Equity, Related Stockholder Matters and Issuer Purchases of Equity Securities,” for additional information on the preferred equity purchased during the fourth quarter of 2015 . 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, 2015 , 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 2014 and 2015 . 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. During 2014 , the Corporation repurchased 14 million shares for $259 million (or an average cost per common share of $18.12 ) of which, approximately 9 million shares were returned to authorized but unissued shares and the remaining were added to treasury stock. The Corporation also repurchased 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 ) during 2015 compared to repurchases of shares for minimum tax withholding settlements on equity compensation totaling approximately $4 million ( 225,000 shares at an average cost per common share of $16.50 ) for 2014 . As of December 31, 2015, approximately $108 million remained available to repurchase under previously approved Board of Director authorizations. See Part II, Item 5, “Market for Registrant’s Common Equity, Related Stockholder Matters and Issuer Purchases of Equity Securities,” for additional information on the common stock purchased during the fourth quarter of 2015 and see section, "Recent Developments," within Part II, Item 7, "Management's Discussion and Analysis of Financial Condition and Results of Operations," for stock repurchases subsequent to December 31, 2015. 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, 2015
Compensation and Retirement Disclosure [Abstract]
Stock-Based Compensation	NOTE 11 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”). 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 , while service-based restricted stock awards vest ratably over four years and performance-based restricted stock awards vest over the three year performance period. As of December 31, 2015 , approximately 11 million shares remained available for grant under the 2013 Plan. The Corporation also issues restricted common stock and restricted common stock units to certain key employees (collectively referred to as “restricted stock awards”) under this 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 service-based or performance-based. Service-based awards are contingent upon continued employment or meeting the requirements for retirement, and performance-based awards are based on earnings per share performance goals, relative total shareholder return, and continued employment or meeting the requirements for retirement. The 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”). Accounting for Stock-Based Compensation: The fair value of stock options granted is estimated on the date of grant using a Black-Scholes option pricing model, while the fair value of restricted stock awards is their fair market value on the date of grant. The fair values of stock options and restricted stock awards are amortized as compensation expense on a straight-line basis over the vesting period of the grants. Beginning with the 2014 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 1 for the Corporation's accounting policy on 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 2015 , 2014 and 2013 . 2015 2014 2013 Dividend yield 2.00 % 2.00 % 2.00 % Risk-free interest rate 2.00 % 2.00 % 0.99 % Weighted average expected volatility 20.00 % 20.00 % 34.35 % Weighted average expected life 6 years 6 years 6 years Weighted average per share fair value of options $3.08 $3.00 $3.80 The Corporation is required to estimate potential forfeitures of stock grants and adjust compensation expense recorded accordingly. The estimate of forfeitures will be adjusted over the requisite service period to the extent that actual forfeitures differ, or are expected to differ, from such estimates. Changes in estimated forfeitures will be recognized in the period of change and will also impact the amount of stock compensation expense to be recognized in future periods. A summary of the Corporation’s stock option activity for 2015 , 2014 , and 2013 , is presented below. Stock Options Shares Weighted Average Exercise Price Weighted Average Remaining Contractual Term Aggregate Intrinsic Value (000s) Outstanding at December 31, 2012 8,640,558 $ 18.88 Granted 1,020,979 14.02 Exercised (642,202 ) 13.43 Forfeited or expired (985,092 ) 21.49 Outstanding at December 31, 2013 8,034,243 $ 18.37 6.03 $ 20,838 Options Exercisable at December 31, 2013 4,923,720 $ 21.48 4.62 $ 8,580 Granted 1,389,452 $ 17.45 Exercised (933,143 ) 13.77 Forfeited or expired (643,214 ) 23.50 Outstanding at December 31, 2014 7,847,338 $ 18.34 5.79 $ 23,986 Options Exercisable at December 31, 2014 5,076,676 $ 19.96 4.41 $ 14,953 Granted 1,348,504 $ 17.95 Exercised (1,351,646 ) 13.90 Forfeited or expired (1,215,053 ) 29.13 Outstanding at December 31, 2015 6,629,143 $ 17.22 6.24 $ 18,730 Options Exercisable at December 31, 2015 4,190,245 $ 17.25 4.93 $ 14,873 The following table summarizes information about the Corporation’s nonvested stock option activity for 2015 , 2014 , and 2013 . Stock Options Shares Weighted Average Grant Date Fair Value Nonvested at December 31, 2012 4,036,595 $ 5.11 Granted 1,020,979 3.80 Vested (1,680,981 ) 5.10 Forfeited (266,070 ) 5.05 Nonvested at December 31, 2013 3,110,523 $ 4.69 Granted 1,389,452 3.00 Vested (1,522,152 ) 4.92 Forfeited (207,161 ) 4.38 Nonvested at December 31, 2014 2,770,662 $ 3.74 Granted 1,348,504 3.08 Vested (1,459,709 ) 4.19 Forfeited (220,559 ) 3.28 Nonvested at December 31, 2015 2,438,898 $ 3.15 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, 2015 , 2014 , and 2013 the intrinsic value of stock options exercised was $7 million , $4 million , and $2 million , respectively. The total fair value of stock options that vested was $6 million , $7 million and $9 million , respectively, for the years ended December 31, 2015 , 2014 , and 2013. For the years ended December 31, 2015 , 2014 , and 2013 , the Corporation recognized compensation expense of $4 million , $6 million , and $8 million respectively, for the vesting of stock options. Included in compensation expense for 2015 was approximately $710,000 of expense for the accelerated vesting of stock options granted to retirement eligible colleagues. At December 31, 2015 , 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 2018 . The following table summarizes information about the Corporation’s restricted stock activity for 2015 , 2014 , and 2013 . Restricted Stock Shares Weighted Average Grant Date Fair Value Outstanding at December 31, 2012 932,425 $ 13.60 Granted 1,276,868 14.03 Vested (626,480 ) 13.68 Forfeited (71,048 ) 13.92 Outstanding at December 31, 2013 1,511,765 $ 13.92 Granted 1,177,168 17.35 Vested (538,877 ) 14.12 Forfeited (167,930 ) 15.26 Outstanding at December 31, 2014 1,982,126 $ 15.79 Granted 1,173,847 18.09 Vested (709,582 ) 15.62 Forfeited (196,363 ) 16.87 Outstanding at December 31, 2015 2,250,028 $ 17.03 The Corporation amortizes the expense related to restricted stock awards as compensation expense over the vesting period specified in the grant. Restricted stock awards granted during 2013 to executive officers will vest ratably over a three year period, while restricted stock awards granted during 2014 and 2015 will vest ratably over a four year period. Restricted stock awards granted to non-executives during 2013 , 2014 and 2015 will vest ratably over a four year period. Expense for restricted stock awards of approximately $15 million , $10 million , and $7 million was recorded for the years ended December 31, 2015 , 2014 , and 2013 , respectively. Included in compensation expense for 2015 was approximately $2 million of expense for the accelerated vesting of restricted stock awards granted to retirement eligible colleagues. The Corporation had $23 million of unrecognized compensation costs related to restricted stock awards at December 31, 2015 , that is expected to be recognized over the remaining requisite service periods that extend predominantly through fourth quarter 2018 . 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, 2015
Defined Benefit Pension Plans and Defined Benefit Postretirement Plans Disclosure [Abstract]
Retirement Plans	NOTE 12 RETIREMENT PLANS: The Corporation has a noncontributory defined benefit retirement plan (the Retirement Account Plan (“RAP”)) covering substantially all full-time employees. The benefits are based primarily on years of service and the employee’s compensation paid. Employees of acquired entities generally participate in the RAP after consummation of the business combinations. Any retirement plans of acquired entities are typically merged into the RAP after completion of the mergers, and credit is usually given to employees for years of service at the acquired institution for vesting and eligibility purposes. In connection with the First Federal acquisition in October 2004, the Corporation assumed the First Federal pension plan (the “First Federal Plan”). The First Federal Plan was frozen on December 31, 2004, and qualified participants in the First Federal Plan became eligible to participate in the RAP as of January 1, 2005. As of December 22, 2015, the First Federal Plan was merged into the RAP. Additional discussion and information on the RAP and the First Federal Plan are collectively referred to below as the “Pension Plan.” The Corporation also provides healthcare access for eligible retired employees in its Postretirement Plan (the “Postretirement Plan”). Retirees who are at least 55 years of age with 5 years of service are eligible to participate in the Postretirement Plan. The Corporation has no plan assets attributable to the Postretirement Plan. The Corporation reserves the right to terminate or make changes to the Postretirement Plan at any time. The funded status and amounts recognized in the 2015 and 2014 consolidated balance sheets, as measured on December 31, 2015 and 2014 , respectively, for the Pension and Postretirement Plans were as follows. Pension Plan Postretirement Plan Pension Plan Postretirement Plan 2015 2015 2014 2014 ($ in Thousands) Change in Fair Value of Plan Assets Fair value of plan assets at beginning of year $ 303,496 $ — $ 282,000 $ — Actual return on plan assets 495 — 15,255 — Employer contributions — 264 21,000 343 Gross benefits paid (14,392 ) (264 ) (14,759 ) (343 ) Fair value of plan assets at end of year* $ 289,599 $ — $ 303,496 $ — Change in Benefit Obligation Net benefit obligation at beginning of year $ 171,333 $ 3,578 $ 154,624 $ 3,288 Service cost 11,257 — 11,058 — Interest cost 6,617 141 7,132 150 Actuarial (gain) loss (3,032 ) (19 ) 13,278 483 Gross benefits paid (14,392 ) (264 ) (14,759 ) (343 ) Net benefit obligation at end of year* $ 171,783 $ 3,436 $ 171,333 $ 3,578 Funded (unfunded) status $ 117,816 $ (3,436 ) $ 132,163 $ (3,578 ) Noncurrent assets 117,816 — 132,163 — Current liabilities — (274 ) — (330 ) Noncurrent liabilities — (3,162 ) — (3,248 ) Asset (Liability) Recognized in the Consolidated Balance Sheets $ 117,816 $ (3,436 ) $ 132,163 $ (3,578 ) * The fair value of the plan assets represented 169% and 177% of the net benefit obligation of the pension plan at December 31, 2015 and 2014 , respectively. Amounts recognized in accumulated other comprehensive loss, net of tax, as of December 31, 2015 and 2014 follow. Pension Plan Postretirement Plan Pension Plan Postretirement Plan 2015 2015 2014 2014 ($ in Thousands) Prior service cost $ 122 $ — $ 153 $ — Net actuarial loss 32,879 73 23,124 84 Amount not yet recognized in net periodic benefit cost, but recognized in accumulated other comprehensive loss $ 33,001 $ 73 $ 23,277 $ 84 Other changes in plan assets and benefit obligations recognized in other comprehensive income (loss) (“OCI”), net of tax, in 2015 and 2014 were as follows. Pension Plan 2015 Postretirement Plan 2015 Pension Plan 2014 Postretirement Plan 2014 ($ in Thousands) Net gain (loss) $ (17,911 ) $ 19 $ (17,945 ) $ (483 ) Amortization of prior service cost 50 — 58 — Amortization of actuarial gain (loss) 2,256 — 1,384 (35 ) Income tax (expense) benefit 5,880 (7 ) 6,308 199 Total Recognized in OCI $ (9,725 ) $ 12 $ (10,195 ) $ (319 ) The components of net periodic benefit cost for the Pension and Postretirement Plans for 2015 , 2014 , and 2013 were as follows. Pension Plan 2015 Postretirement Plan 2015 Pension Plan 2014 Postretirement Plan 2014 Pension Plan 2013 Postretirement Plan 2013 ($ in Thousands) Service cost $ 11,257 $ — $ 11,058 $ — $ 12,078 $ — Interest cost 6,617 141 7,132 150 6,237 142 Expected return on plan assets (21,438 ) — (19,922 ) — (17,647 ) — Amortization of: Prior service cost 50 — 58 — 72 — Actuarial (gain) loss 2,256 — 1,384 (35 ) 4,344 — Total net pension cost $ (1,258 ) $ 141 $ (290 ) $ 115 $ 5,084 $ 142 As of December 31, 2015 , the estimated actuarial losses and prior service cost that will be amortized during 2016 from accumulated other comprehensive income into net periodic benefit cost for the Pension Plan are $1.9 million and $0.1 million , respectively. Pension Plan 2015 Postretirement Plan 2015 Pension Plan 2014 Postretirement Plan 2014 Weighted average assumptions used to determine benefit obligations: Discount rate 4.30 % 4.30 % 4.00 % 4.00 % Rate of increase in compensation levels 4.00 NA 4.00 NA Weighted average assumptions used to determine net periodic benefit costs: Discount rate 4.00 % 4.00 % 4.80 % 4.80 % Rate of increase in compensation levels 4.00 NA 4.00 NA Expected long-term rate of return on plan assets 7.50 NA 7.50 NA The overall expected long-term rates of return on the Pension Plan assets were 7.50% at December 31, 2015 and 2014 . The expected long-term (more than 20 years) rate of return was estimated using market benchmarks for equities and bonds applied to the Pension 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 Pension Plan assets was 0.43% and 5.89% for 2015 and 2014 , respectively. The Pension 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 Pension 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 Pension Plan as of the December 31, 2015 and 2014 measurement dates, respectively, by asset category were as follows. Asset Category 2015 2014 Equity securities 60 % 64 % Fixed income securities 40 % 35 % Other — % 1 % Total 100 % 100 % The Pension 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 Pension Plan’s investments as of December 31, 2015 and 2014 . Fair Value Measurements Using December 31, 2015 Level 1 Level 2 Level 3 ($ in Thousands) Pension Plan Investments: Money market account $ 481 $ 481 $ — $ — Mutual funds 168,982 168,982 — — Common /collective trust funds 120,136 — 120,136 — Total Pension Plan Investments $ 289,599 $ 169,463 $ 120,136 $ — Fair Value Measurements Using December 31, 2014 Level 1 Level 2 Level 3 ($ in Thousands) Pension Plan Investments: Money market account $ 2,868 $ 2,868 $ — $ — Mutual funds 185,483 185,483 — — Common /collective trust funds 115,145 — 115,145 — Total Pension Plan Investments $ 303,496 $ 188,351 $ 115,145 $ — 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 Pension Plan. The projected benefit payments for the Pension and Postretirement Plans at December 31, 2015 , 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. Pension Plan Postretirement Plan ($ in Thousands) Estimated future benefit payments: 2016 $ 14,218 $ 274 2017 13,885 257 2018 12,825 263 2019 12,580 250 2020 12,767 247 2021-2025 66,722 1,189 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 8.5% for 2015 , 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 8.0% for 2015 , 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. 2015 2014 100 bp Increase 100 bp Decrease 100 bp Increase 100 bp Decrease ($ in Thousands) Effect on total of service and interest cost $ 15 $ (13 ) $ 13 $ (11 ) Effect on postretirement benefit obligation $ 357 $ (310 ) $ 316 $ (277 ) 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 $11 million , $11 million , and $10 million in 2015 , 2014 , and 2013 , respectively.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Income Taxes	NOTE 13 INCOME TAXES: The current and deferred amounts of income tax expense (benefit) were as follows. Years Ended December 31, 2015 2014 2013 ($ in Thousands) Current: Federal $ 82,449 $ 74,646 $ 50,628 State 2,560 1,000 2,653 Total current 85,009 75,646 53,281 Deferred: Federal (10,606 ) (805 ) 16,409 State 7,084 10,695 9,511 Total deferred (3,522 ) 9,890 25,920 Total income tax expense $ 81,487 $ 85,536 $ 79,201 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. 2015 2014 ($ in Thousands) Deferred tax assets: Allowance for loan losses $ 106,258 $ 99,219 Allowance for other losses 10,906 11,609 Accrued liabilities 6,802 5,773 Deferred compensation 31,677 31,392 State net operating losses 14,154 22,640 Nonaccrual interest 1,901 2,383 Other 5,811 7,929 Total deferred tax assets 177,509 180,945 Deferred tax liabilities: FHLB stock dividends 2,165 6,367 Prepaid expenses 69,396 68,955 Goodwill 25,770 24,049 Mortgage banking activities 15,704 13,147 Deferred loan fee income 17,770 21,199 State deferred taxes 6,366 9,011 Lease financing 3,042 2,313 Bank premises and equipment 7,491 9,532 Other 9,062 5,501 Total deferred tax liabilities 156,766 160,074 Net deferred tax assets 20,743 20,871 Tax effect of unrealized (gain) loss related to available for sale securities 219 (10,902 ) Tax effect of unrealized loss related to pension and postretirement benefits 20,404 14,468 20,623 3,566 Net deferred tax assets including items with tax effect recorded directly to OCI $ 41,366 $ 24,437 At December 31, 2015 and 2014 , 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, 2015 , the Corporation had state net operating loss carryforwards of $179 million (of which, $32 million was acquired from various acquisitions) that will begin expiring in 2030. The effective income tax rate differs from the statutory federal tax rate. The major reasons for this difference were as follows. 2015 2014 2013 Federal income tax rate at statutory rate 35.0 % 35.0 % 35.0 % Increases (decreases) resulting from: Tax-exempt interest and dividends (5.0 )% (4.6 )% (4.5 )% State income taxes (net of federal benefit) 2.3 % 2.8 % 2.9 % Bank owned life insurance (1.2 )% (1.7 )% (1.5 )% Federal tax credits (0.5 )% (1.4 )% (1.0 )% Tax reserve adjustments (0.6 )% 0.7 % (1.9 )% Other 0.2 % 0.2 % 0.6 % Effective income tax rate 30.2 % 31.0 % 29.6 % 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, 2015 . If income taxes had been provided, the deferred tax liability would have been approximately $40 million . Management does not expect this amount to become taxable in the future, therefore, no provision for income taxes has been made. The Corporation and its subsidiaries file income tax returns in the U.S. federal jurisdiction and various state jurisdictions. The Corporation’s federal income tax returns are open and subject to examination from the 2012 tax return year and forward. The years open to examination by state and local government authorities varies by jurisdiction. A reconciliation of the beginning and ending amount of unrecognized tax benefits was as follows. 2015 2014 ($ in Millions) Balance at beginning of year $ 9 $ 6 Additions (subtractions) for tax positions related to prior years (2 ) 1 Additions for tax positions related to current year 2 2 Balance at end of year $ 9 $ 9 At both December 31, 2015 and 2014 , the total amount of unrecognized tax benefits that, if recognized, would affect the effective tax rate was $6 million . 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 $(1) million and $1 million , as of December 31, 2015 and 2014, respectively. Accrued interest and penalties were $2 million and $3 million as of December 31, 2015 and 2014, respectively. 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, 2015
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative and Hedging Activities	NOTE 14 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 $9 million of investment securities as collateral at December 31, 2015 , and pledged $11 million of investment securities as collateral at December 31, 2014 . 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, 2015 , the Corporation posted cash collateral for the margin of $22 million , compared to $15 million at December 31, 2014 . The Corporation’s derivative and hedging instruments are recorded at fair value on the consolidated balance sheets. The fair value of the Corporation’s interest rate-related instruments is determined using discounted cash flow analysis on the expected cash flows of each derivative and also includes a nonperformance / credit risk component (credit valuation adjustment). See Note 18 for additional fair value information and disclosures and see Note 1 for the Corporation’s accounting policy for derivative and hedging activities. The table below identifies the balance sheet category and fair values of the Corporation’s free standing derivative instruments, which are not designated as hedging instruments. Notional Amount Fair Value Balance Sheet Category Weighted Average ($ in Thousands) Receive Rate (1) Pay Rate (1) Maturity December 31, 2015 Interest rate-related instruments — customer and mirror $ 1,665,965 $ 29,391 Trading assets 1.56 % 1.56 % 41 months Interest rate-related instruments — customer and mirror 1,665,965 (30,886 ) Trading liabilities 1.56 % 1.56 % 41 months Interest rate lock commitments (mortgage) 271,530 958 Other assets — — — Forward commitments (mortgage) 231,798 403 Other assets — — — Foreign currency exchange forwards 72,976 1,532 Trading assets — — — Foreign currency exchange forwards 65,649 (1,398 ) Trading liabilities — — — Commodity contracts 44,380 1,269 Trading assets — — — Commodity contracts 44,256 (1,146 ) Trading liabilities — — — Purchased options (time deposit) 104,582 2,715 Other assets — — — Written options (time deposit) 104,582 (2,715 ) Other liabilities — — — December 31, 2014 Interest rate-related instruments — customer and mirror $ 1,636,480 $ 33,023 Trading assets 1.60 % 1.60 % 42 months Interest rate-related instruments — customer and mirror 1,636,480 (35,372 ) Trading liabilities 1.60 % 1.60 % 42 months Interest rate lock commitments (mortgage) 126,379 1,947 Other assets — — — Forward commitments (mortgage) 234,500 (2,435 ) Other liabilities — — — Foreign currency exchange forwards 60,742 2,140 Trading assets — — — Foreign currency exchange forwards 56,573 (1,957 ) Trading liabilities — — — Purchased options (time deposit) 110,347 6,054 Other assets — — — Written options (time deposit) 110,347 (6,054 ) Other liabilities — — — (1) Reflects the weighted average receive rate and pay rate for the interest rate swap derivative financial instruments only. 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. ($ in Thousands) Income Statement Category of Gain / (Loss) Recognized in Income Gain / (Loss) Recognized in Income Year ended December 31, 2015 Interest rate-related instruments — customer and mirror, net Capital market fees, net $ 854 Interest rate lock commitments (mortgage) Mortgage banking, net (989 ) Forward commitments (mortgage) Mortgage banking, net 2,838 Foreign currency exchange forwards Capital market fees, net (49 ) Commodity contracts Capital market fees, net 123 Year ended December 31, 2014 Interest rate-related instruments — customer and mirror, net Capital market fees, net $ 486 Interest rate lock commitments (mortgage) Mortgage banking, net 1,531 Forward commitments (mortgage) Mortgage banking, net (3,736 ) Foreign currency exchange forwards Capital market fees, net 90 Free Standing Derivatives The Corporation enters into various derivative contracts which are designated as free standing derivative contracts. Free standing derivative products are entered into primarily for the benefit of commercial customers seeking to manage their exposures to interest rate risk, foreign currency, and commodity prices. These derivative contracts are not designated against specific assets and liabilities on the balance sheet or forecasted transactions and, therefore, do not qualify for hedge accounting treatment. Such derivative contracts are carried at fair value on the consolidated balance sheets with changes in the fair value recorded as a component of Capital market fees, net, and typically include interest rate-related instruments (swaps and caps). 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 forward interest rate swaps and caps. The Corporation’s market risk from unfavorable movements in interest rates related to these derivative contracts is generally economically hedged by concurrently entering into offsetting derivative contracts. The offsetting derivative contracts have identical notional values, terms and indices. Foreign currency exchange derivatives: The Corporation provides foreign exchange services to customers, primarily forward contracts. Our customers enter into a foreign currency exchange forward with the Corporation as a means for them to mitigate exchange rate risk. The Corporation mitigates its risk by then entering into an offsetting foreign exchange derivative contract. Such foreign exchange contracts are carried at fair value on the consolidated balance sheet with changes in fair value recorded as a component of Capital market fees, net. Commodity derivatives: 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 Corporation entered into its first commodity contracts in October 2015. 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 option derivatives (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.

Balance Sheet Offsetting

Balance Sheet Offsetting	12 Months Ended
	Dec. 31, 2015
Offsetting [Abstract]
Balance Sheet Offsetting	NOTE 15 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, 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 ) $ — December 31, 2014 Derivative assets: Interest rate-related instruments $ 558 $ — $ 558 $ (558 ) $ — $ — Derivative liabilities: Interest rate-related instruments $ 34,087 $ — $ 34,087 $ (558 ) $ (26,105 ) $ 7,424

Commitments, Off-Balance Sheet

Commitments, Off-Balance Sheet Arrangements, and Contingent Liabilities	12 Months Ended
	Dec. 31, 2015
Commitments and Contingencies Disclosure [Abstract]
Commitments, Off-Balance Sheet Arrangements, and Contingent Liabilities	NOTE 16 COMMITMENTS, OFF-BALANCE SHEET ARRANGEMENTS, AND CONTINGENT LIABILITIES: 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. 2015 2014 ($ in Thousands) Commitments to extend credit, excluding commitments to originate residential mortgage loans held for sale(1)(2) $ 7,402,518 $ 6,884,411 Commercial letters of credit(1) 9,945 9,179 Standby letters of credit(3) 296,508 353,292 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, 2015 or 2014 . 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 December 31, 2015 compared to $4 million at December 31, 2014 , as an estimate of the fair value of these financial instruments. Lending-related Commitments As a financial services provider, the Corporation routinely enters into commitments to extend credit. Such commitments are subject to the same credit policies and approval process accorded to loans made by the Corporation, with each customer’s creditworthiness evaluated on a case-by-case basis. The commitments generally have fixed expiration dates or other termination clauses and may require the payment of a fee. The Corporation’s exposure to credit loss in the event of nonperformance by the other party to these financial instruments is represented by the contractual amount of those instruments. The amount of collateral obtained, if deemed necessary by the Corporation upon extension of credit, is based on management’s credit evaluation of the customer. Since a significant portion of commitments to extend credit are subject to specific restrictive loan covenants or may expire without being drawn upon, the total commitment amounts do not necessarily represent future cash flow requirements. An allowance for unfunded commitments is maintained at a level believed by management to be sufficient to absorb estimated probable losses related to unfunded commitments (including unfunded loan commitments and letters of credit). The allowance for unfunded commitments totaled $24 million at December 31, 2015 compared to $25 million at December 31, 2014 , 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, 2015 , was $52 million , compared to $27 million at December 31, 2014 , included in other assets on the consolidated balance sheets. Related to these investments, the Corporation had remaining commitments to fund of $61 million at December 31, 2015 , and $28 million at December 31, 2014 . Contingent Liabilities 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. 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. Beginning in late 2013, the Corporation began reviewing a variety of legacy products provided by third parties, including debt protection and identity protection products. In connection with this review, the Corporation has made, and plans to make, remediation payments to affected customers and former customers, and has reserved accordingly. A variety of consumer products, including the legacy debt protection and identity protection products referred to above, and mortgage and deposit products, and certain fees and charges related to such products, have come under increased regulatory scrutiny. It is possible that regulatory authorities could bring enforcement actions, including civil money penalties, or take other actions against the Corporation and the Bank in regard to these consumer products. The Bank could also determine of its own accord, or be required by regulators, to refund or otherwise make remediation payments to customers in connection with these products. It is not possible at this time for management to assess the probability of a material adverse outcome or reasonably estimate the amount of any potential loss related to such matters. 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 approximately $1 million of 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 $3 million and $5 million during the years ended December 31, 2015 and 2014 , respectively, and paid loss reimbursement or settlement claims of approximately $133,000 and $734,000 for the years ended December 31, 2015 and 2014 , respectively. Make whole requests during 2014 and 2015 generally arose from loans sold during the period of January 1, 2006 to December 31, 2015 , which total $19.9 billion at the time of sale, and consisted primarily of loans sold to GSEs. As of December 31, 2015 , approximately $7.5 billion of these sold loans remain outstanding. The balance in the mortgage repurchase reserve at the balance sheet date reflects the estimated amount of potential loss the Corporation could incur from repurchasing a loan, as well as loss reimbursements, indemnifications, and other settlement resolutions. The following summarizes the changes in the mortgage repurchase reserve for the years ended as follows. 2015 2014 ($ in Thousands) Balance at beginning of year $ 3,258 $ 5,737 Repurchase provision expense 428 505 Adjustments to provision expense (2,450 ) (2,250 ) Charge offs, net (39 ) (734 ) Balance at end of year $ 1,197 $ 3,258 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, 2015 , and December 31, 2014 , there were approximately $68 million and $46 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, 2015 and December 31, 2014 , there were $132 million and $178 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, 2015
Condensed Financial Information of Parent Company Only Disclosure [Abstract]
Parent Company Only Financial Information	NOTE 17 PARENT COMPANY ONLY FINANCIAL INFORMATION: Presented below are condensed financial statements for the Parent Company. BALANCE SHEETS December 31, 2015 2014 ($ in Thousands) ASSETS Cash and due from banks $ 610,862 $ 523,103 Investment securities available for sale, at fair value 61,847 76,159 Investment in subsidiaries 3,211,685 3,166,080 Other assets 73,781 94,332 Total assets $ 3,958,175 $ 3,859,674 LIABILITIES AND STOCKHOLDERS’ EQUITY Commercial paper $ 67,978 $ 74,297 Senior notes, at par 680,000 680,000 Subordinated notes, at par 250,000 250,000 Long-term funding capitalized costs (875 ) (143 ) Total long-term funding 929,125 929,857 Accrued expenses and other liabilities 23,826 55,269 Total liabilities 1,020,929 1,059,423 Preferred equity 121,379 59,727 Common equity 2,815,867 2,740,524 Total stockholders’ equity 2,937,246 2,800,251 Total liabilities and stockholders’ equity $ 3,958,175 $ 3,859,674 STATEMENTS OF INCOME For the Years Ended December 31, 2015 2014 2013 ($ in Thousands) INCOME Dividends from subsidiaries $ 205,000 $ 223,000 $ 262,000 Interest income on notes receivable — 1,264 1,988 Other income 8,441 9,682 7,742 Total income 213,441 233,946 271,730 EXPENSE Interest expense on short and long-term funding 39,576 24,847 27,167 Other expense 4,684 745 8,029 Total expense 44,260 25,592 35,196 Income before income tax benefit and equity in undistributed net income (loss) of subsidiaries 169,181 208,354 236,534 Income tax benefit (1,665 ) (5,801 ) (7,086 ) Income before equity in undistributed net income (loss) of subsidiaries 170,846 214,155 243,620 Equity in undistributed net income (loss) of subsidiaries 17,455 (23,646 ) (54,928 ) Net income 188,301 190,509 188,692 Preferred stock dividends 7,155 5,002 5,158 Net income available to common equity $ 181,146 $ 185,507 $ 183,534 STATEMENTS OF CASH FLOWS For the Years Ended December 31, 2015 2014 2013 ($ in Thousands) OPERATING ACTIVITIES Net income $ 188,301 $ 190,509 $ 188,692 Adjustments to reconcile net income to net cash provided by operating activities: (Increase) decrease in equity in undistributed net income of subsidiaries (17,455 ) 23,646 54,928 Gain on sales of investment securities, net — (214 ) (456 ) Gain on sales of assets and impairment write-downs, net (5,673 ) (5,609 ) (1,007 ) Net change in other assets and other liabilities (10,997 ) (14,022 ) (103,954 ) Net cash provided by operating activities 154,176 194,310 138,203 INVESTING ACTIVITIES Proceeds from sales of investment securities 13,962 88,844 55,445 Purchase of investment securities — — (23,101 ) Net decrease in notes receivable — 46,594 3,049 Purchase of other assets, net of disposals 11,964 10,930 2,407 Net cash provided by investing activities 25,926 146,368 37,800 FINANCING ACTIVITIES Net increase (decrease) in short-term funding (6,319 ) 8,813 14,239 Proceeds from issuance of long-term funding — 496,030 — Repayment of long-term funding — (155,000 ) (25,821 ) Proceeds from issuance of preferred stock 62,966 — — Proceeds from issuance of common stock for stock-based compensation plans 20,054 13,228 9,305 Purchase of preferred stock (1,335 ) (2,451 ) (1,626 ) Cash dividends (69,555 ) (63,712 ) (60,149 ) Purchase of common stock returned to authorized but unissued (93,000 ) (150,498 ) — Purchase of treasury stock (5,154 ) (112,312 ) (123,349 ) Net cash provided by (used in) financing activities (92,343 ) 34,098 (187,401 ) Net increase (decrease) in cash and cash equivalents 87,759 374,776 (11,398 ) Cash and cash equivalents at beginning of year 523,103 148,327 159,725 Cash and cash equivalents at end of year $ 610,862 $ 523,103 $ 148,327

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2015
Fair Value Disclosures [Abstract]
Fair Value Measurements	NOTE 18 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. 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 again use in the future, interest rate swaps to manage its interest rate risk. In addition, the Corporation offers customer 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 measurements reflects the contractual terms of the derivative financial instruments, including the period to maturity, and uses observable market-based inputs, including interest rate curves and implied volatilities. More specifically, the fair values of interest rate swaps are determined using the market standard methodology of netting the discounted future fixed cash receipts (or payments), with the variable cash payments (or receipts) based on an expectation of future interest rates (forward curves) derived from observable market interest rate curves. Likewise, the fair values of interest rate options (i.e., interest rate caps) are determined using the market standard methodology of discounting the future expected cash receipts that would occur if variable interest rates fall below (or rise above) the strike rate of the floors (or caps), with the variable interest rates used in the calculation of projected receipts on the floor (or cap) based on an expectation of future interest rates derived from observable market interest rate curves and volatilities. The Corporation also incorporates credit valuation adjustments to appropriately reflect both its own nonperformance risk and the respective counterparty’s nonperformance risk in the fair value measurements. In adjusting the fair value of its derivative financial instruments for the effect of nonperformance risk, the Corporation has considered the impact of netting and any applicable credit enhancements, such as collateral postings, thresholds, mutual puts, and guarantees. In conjunction with the FASB’s fair value measurement guidance, the Corporation made an accounting policy election to measure the credit risk of its derivative financial instruments that are subject to master netting agreements on a net basis by counterparty portfolio. 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, 2015, and 2014, 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. 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, 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. Impaired Loans: The Corporation considers a loan impaired when it is probable that the Corporation will be unable to collect all amounts due according to the original contractual terms of the note agreement, including both principal and interest. Management has determined that commercial and consumer loan relationships that have nonaccrual status or have had their terms restructured in a troubled debt restructuring meet this impaired loan definition. For individually evaluated impaired loans, the amount of impairment is based upon the present value of expected future cash flows discounted at the loan’s effective interest rate, the estimated fair value of the underlying collateral for collateral-dependent loans, or the estimated liquidity of the note. See Note 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. See Note 5 for additional disclosure regarding the Corporation’s mortgage servicing rights. 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, 2015 and 2014 , 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 December 31, 2015 Fair Value Measurements Using Level 1 Level 2 Level 3 ($ in Thousands) Assets: Investment securities available for sale: U.S. Treasury securities $ 997 $ 997 $ — $ — Residential mortgage-related securities: FNMA / FHLMC 1,414,626 — 1,414,626 — GNMA 1,590,003 — 1,590,003 — Private-label 1,709 — 1,709 — GNMA commercial mortgage-related securities 1,955,310 — 1,955,310 — Other securities (debt and equity) 4,769 1,569 3,000 200 Total investment securities available for sale $ 4,967,414 $ 2,566 $ 4,964,648 $ 200 Derivatives (trading and other assets) $ 36,268 $ — $ 34,907 $ 1,361 Liabilities: Derivatives (trading and other liabilities) $ 36,145 $ — $ 36,145 $ — December 31, 2014 Fair Value Measurements Using Level 1 Level 2 Level 3 ($ in Thousands) Assets: Investment securities available for sale: U.S. Treasury securities $ 998 $ 998 $ — $ — Municipal securities 582,679 — 582,679 — Residential mortgage-related securities: FNMA / FHLMC 3,563,457 — 3,563,457 — GNMA 167,332 — 167,332 — Private-label 2,294 — 2,294 — GNMA commercial mortgage-related securities 1,073,893 — 1,073,893 — Other securities (debt and equity) 6,159 2,959 3,000 200 Total investment securities available for sale $ 5,396,812 $ 3,957 $ 5,392,655 $ 200 Derivatives (trading and other assets) $ 43,164 $ — $ 41,217 $ 1,947 Liabilities: Derivatives (trading and other liabilities) $ 45,818 $ — $ 43,383 $ 2,435 The table below presents a rollforward of the balance sheet amounts for the years ended December 31, 2015 and 2014 , 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, 2013 $ 299 $ 1,717 Total net losses included in income: Mortgage derivative loss — (2,205 ) Sale of investment securities (99 ) — Balance December 31, 2014 $ 200 $ (488 ) Total net gains included in income: Mortgage derivative gain — 1,849 Balance December 31, 2015 $ 200 $ 1,361 For Level 3 assets and liabilities measured at fair value on a recurring or nonrecurring basis as of December 31, 2015 , 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 Mortgage Risk Management Committee. At December 31, 2015 , the closing ratio was 91% . Impaired loans : 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 10% to 20% . Mortgage servicing rights : 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 12.2% and 9.6% at December 31, 2015 , 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 Consumer Banking to reconcile the fair value estimates and the key assumptions used by the respective parties in arriving at those estimates. The Associated Mortgage Group Risk 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. 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 as of December 31, 2015 and 2014 , 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 December 31, 2015 Fair Value Measurements Using Income Statement Category of Adjustment Recognized in Income Level 1 Level 2 Level 3 ($ in Thousands) Assets: Loans held for sale $ 124,915 $ — $ 124,915 $ — Mortgage banking, net $ (155 ) Impaired loans(1) 41,891 — — 41,891 Provision for credit losses (7,796 ) Mortgage servicing rights 70,686 — — 70,686 Mortgage banking, net 425 December 31, 2014 Fair Value Measurements Using Income Statement Category of Adjustment Recognized in Income Level 1 Level 2 Level 3 ($ in Thousands) Assets: Loans held for sale $ 156,423 $ — $ 156,423 $ — Mortgage banking, net $ — Impaired loans(1) 53,832 — — 53,832 Provision for credit losses (17,272 ) Mortgage servicing rights 66,342 — — 66,342 Mortgage banking, net (321 ) (1) Represents individually evaluated impaired loans, net of the related allowance for loan losses. Certain nonfinancial assets measured at fair value on a nonrecurring basis include other real estate owned (upon initial recognition or subsequent impairment), nonfinancial assets and nonfinancial liabilities measured at fair value 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. During 2015 and 2014 , 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. Other real estate owned measured at fair value upon initial recognition totaled approximately $11 million and $21 million for the years ended December 31, 2015 and 2014 , respectively. In addition to other real estate owned measured at fair value upon initial recognition, the Corporation also recorded write-downs to the balance of other real estate owned for subsequent impairment of $3 million and $2 million to asset gains, net for the years ended December 31, 2015 and 2014 , respectively. Fair Value of Financial Instruments: The Corporation is required to disclose estimated fair values for its financial instruments. Fair value estimates, methods, and assumptions are set forth below for the Corporation’s financial instruments. The estimated fair values of the Corporation’s financial instruments were as follows. December 31, 2015 Carrying Amount Fair Value Fair Value Measurements Using Level 1 Level 2 Level 3 ($ in Thousands) Financial assets: Cash and due from banks $ 374,921 $ 374,921 $ 374,921 $ — $ — Interest-bearing deposits in other financial institutions 79,764 79,764 79,764 — — Federal funds sold and securities purchased under agreements to resell 19,000 19,000 19,000 — — Investment securities held to maturity 1,168,230 1,184,442 — 1,184,442 — Investment securities available for sale 4,967,414 4,967,414 2,566 4,964,648 200 FHLB and Federal Reserve Bank stocks 147,240 147,240 — 147,240 — Loans held for sale 124,915 124,915 — 124,915 — Loans, net 18,440,079 18,389,832 — — 18,389,832 Bank owned life insurance 583,019 583,019 — 583,019 — Interest rate-related instruments 29,391 29,391 — 29,391 — Foreign currency exchange forwards 1,532 1,532 — 1,532 — Interest rate lock commitments to originate residential mortgage loans held for sale 958 958 — — 958 Forward commitments to sell residential mortgage loans 403 403 — — 403 Purchased options (time deposit) 2,715 2,715 — 2,715 — Commodity contracts 1,269 1,269 — 1,269 — Financial liabilities: Noninterest-bearing demand, savings, interest-bearing demand, and money market accounts $ 19,444,863 $ 19,444,863 $ — $ — $ 19,444,863 Brokered CDs and other time deposits 1,562,802 1,564,464 — 1,564,464 — Short-term funding 834,416 834,416 — 834,416 — Long-term funding 2,679,350 2,728,112 — 2,728,112 — Interest rate-related instruments 30,886 30,886 — 30,886 — Foreign currency exchange forwards 1,398 1,398 — 1,398 — Commodity contracts 1,146 1,146 — 1,146 — Standby letters of credit (1) 2,954 2,954 — 2,954 — Written options (time deposit) 2,715 2,715 — 2,715 — December 31, 2014 Carrying Amount Fair Value Fair Value Measurements Using Level 1 Level 2 Level 3 ($ in Thousands) Financial assets: Cash and due from banks $ 444,113 $ 444,113 $ 444,113 $ — $ — Interest-bearing deposits in other financial institutions 571,924 571,924 571,924 — — Federal funds sold and securities purchased under agreements to resell 16,030 16,030 16,030 — — Investment securities held to maturity 404,455 413,067 — 413,067 — Investment securities available for sale 5,396,812 5,396,812 3,957 5,392,655 200 FHLB and Federal Reserve Bank stocks 189,107 189,107 — 189,107 — Loans held for sale 154,935 156,423 — 156,423 — Loans, net 17,327,544 17,427,647 — — 17,427,647 Bank owned life insurance 574,154 574,154 — 574,154 — Interest rate-related instruments 33,023 33,023 — 33,023 — Foreign currency exchange forwards 2,140 2,140 — 2,140 — Interest rate lock commitments to originate residential mortgage loans held for sale 1,947 1,947 — — 1,947 Purchased options (time deposit) 6,054 6,054 — 6,054 — Financial liabilities: Noninterest-bearing demand, savings, interest-bearing demand, and money market accounts $ 17,192,049 $ 17,192,049 $ — $ — $ 17,192,049 Brokered CDs and other time deposits 1,571,455 1,571,455 — 1,571,455 — Short-term funding 1,068,288 1,068,288 — 1,068,288 — Long-term funding 3,930,117 3,975,605 — 3,975,605 — Interest rate-related instruments 35,372 35,372 — 35,372 — Foreign currency exchange forwards 1,957 1,957 — 1,957 — Standby letters of credit(1) 3,542 3,542 — 3,542 — Forward commitments to sell residential mortgage loans 2,435 2,435 — 2,435 Written options (time deposit) 6,054 6,054 — 6,054 — (1) The commitment on standby letters of credit was $297 million and $353 million at December 31, 2015 and 2014 , 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 Federal Home Loan Bank stocks given their “restricted” nature (i.e., the stock can only be sold back to the respective institutions (Federal Home Loan Bank 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 was based on what secondary markets are currently offering for portfolios with similar characteristics. 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), lease financing, residential mortgage, home equity, other installment, and credit cards. 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. Interest rate-related instruments— The fair value of interest rate-related instruments is determined using discounted cash flow analysis on the expected cash flows of each derivative. 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. Foreign currency exchange forwards— The fair value 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. Purchased and written options— The fair value of the Corporation’s purchased and written options is determined using quoted prices of the underlying stocks. Commodity contracts— The fair value of the Corporation’s commodity contracts is determined using quoted prices of the underlying instruments. Standby letters of credit— The fair value of standby letters of credit represent 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. Interest rate lock commitments to originate residential mortgage loans held for sale— 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. Forward commitments to sell residential mortgage loans— The Corporation 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. 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.

Regulatory Matters

Regulatory Matters	12 Months Ended
	Dec. 31, 2015
Regulatory Capital Requirements [Abstract]
Regulatory Matters	NOTE 19 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 $64 million at December 31, 2015 . 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, 2015 and 2014 , that the Corporation meets all capital adequacy requirements to which it is subject. In July 2013, the Federal Reserve and the OCC, the primary federal regulators for the Corporation and the Bank, respectively, published final rules (the “Basel III Capital Rules”) establishing a new comprehensive capital framework for U.S. banking organizations. The rules implement the Basel Committee’s December 2010 framework known as “Basel III” for strengthening international capital standards as well as certain provisions of the Dodd-Frank Wall Street Reform and Consumer Protection Act. For additional information on Basel III and the Dodd-Frank Act, see Part I, Item 1. As of December 31, 2015 and 2014 , 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 2015 or 2014 . Actual For Capital Adequacy Purposes To Be Well Capitalized Under Prompt Corrective Action Provisions:(2) ($ in Thousands) Amount Ratio(1) Amount Ratio(1) Amount Ratio(1) 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 10.12 797,199 ≥ 4.00 % 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 11.50 794,035 ≥ 4.00 % 1,191,053 ≥ 6.00 % 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 % As of December 31, 2014 Associated Banc-Corp Total capital $ 2,350,898 12.66 % $ 1,485,412 ≥ 8.00 % Tier 1 capital 1,868,059 10.06 742,706 ≥ 4.00 % Common equity Tier 1 capital N/A N/A N/A ≥ N/A Leverage 1,868,059 7.48 998,967 ≥ 4.00 % Associated Bank, N.A. Total capital $ 2,449,514 13.26 % $ 1,477,785 ≥ 8.00 % $ 1,847,231 ≥ 10.00 % Tier 1 capital 2,217,861 12.01 738,892 ≥ 4.00 % 1,108,339 ≥ 6.00 % Common equity Tier 1 capital N/A N/A N/A ≥ N/A N/A ≥ N/A Leverage 2,217,861 8.92 994,103 ≥ 4.00 1,242,628 ≥ 5.00 % 1) Total capital ratio is defined as Tier 1 capital plus Tier 2 capital divided by total risk-weighted assets. The Tier 1 Capital ratio is defined as Tier 1 capital divided by total risk-weighted assets. Common equity Tier 1 is defined as Tier 1 capital excluding qualifying perpetual preferred stock and qualifying trust preferred securities divided by total risk weighted assets. The leverage ratio is defined as Tier 1 capital divided by the most recent quarter’s average total assets. 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, 2015
Earnings Per Share [Abstract]
Earnings Per Common Share	NOTE 20 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). Presented below are the calculations for basic and diluted earnings per common share. For the Years Ended December 31, 2015 2014 2013 (In thousands, except per share data) Net income $ 188,301 $ 190,509 $ 188,692 Preferred stock dividends (7,155 ) (5,002 ) (5,158 ) Net income available to common equity $ 181,146 $ 185,507 $ 183,534 Common shareholder dividends (61,774 ) (58,123 ) (54,505 ) Unvested share-based payment awards (626 ) (587 ) (486 ) Undistributed earnings $ 118,746 $ 126,797 $ 128,543 Undistributed earnings allocated to common shareholders 117,498 125,646 127,592 Undistributed earnings allocated to unvested share-based payment awards 1,248 1,151 951 Undistributed earnings $ 118,746 $ 126,797 $ 128,543 Basic Distributed earnings to common shareholders $ 61,774 $ 58,123 $ 54,505 Undistributed earnings allocated to common shareholders 117,498 125,646 127,592 Total common shareholders earnings, basic $ 179,272 $ 183,769 $ 182,097 Diluted Distributed earnings to common shareholders $ 61,774 $ 58,123 $ 54,505 Undistributed earnings allocated to common shareholders 117,498 125,646 127,592 Total common shareholders earnings, diluted $ 179,272 $ 183,769 $ 182,097 Weighted average common shares outstanding 149,350 157,286 165,584 Effect of dilutive common stock awards 1,253 968 218 Diluted weighted average common shares outstanding 150,603 158,254 165,802 Basic earnings per common share $ 1.20 $ 1.17 $ 1.10 Diluted earnings per common share $ 1.19 $ 1.16 $ 1.10 Options to purchase approximately 1 million , 2 million , and 3 million shares were outstanding at December 31, 2015 , 2014 , and 2013 , respectively, but excluded from the calculation of diluted earnings per common share as the effect would have been anti-dilutive.

Segment Reporting

Segment Reporting	12 Months Ended
	Dec. 31, 2015
Segment Reporting [Abstract]
Segment Reporting	NOTE 21 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 interest income or interest expense using a funds transfer pricing methodology that charges users of funds (assets) interest expense and credits providers of funds (liabilities, primarily deposits) with income based on the maturity, prepayment and / or repricing characteristics of the assets and liabilities. The net effect of this allocation is recorded in the Risk Management and Shared Services segment. A credit provision is allocated to segments based on the expected long-term annual net charge off rates attributable to the credit risk of loans managed by the segment during the period. In contrast, the level of the consolidated provision for credit losses is determined based on an incurred loss model using the methodologies described in Note 1 to assess the overall appropriateness of the allowance for loan losses. The net effect of the credit provision is recorded in Risk Management and Shared Services. Indirect expenses incurred by certain centralized support areas are allocated to segments based on actual usage (for example, volume measurements) and other criteria. Certain types of administrative expense and bank-wide expense accruals (including amortization of core deposit and other intangible assets associated with acquisitions) are generally not allocated to segments. Income taxes are allocated to segments based on the Corporation’s estimated effective tax rate, with certain segments adjusted for any tax-exempt income or non-deductible expenses. Equity is allocated to the segments based on regulatory capital requirements and in proportion to an assessment of the inherent risks associated with the business of the segment (including interest, credit and operating risk). The management accounting policies and processes utilized in compiling segment financial information are highly subjective and, unlike financial accounting, are not based on authoritative guidance similar to U.S. generally accepted accounting principles. As a result, reported segments and the financial information of the reported segments are not necessarily comparable with similar information reported by other financial institutions. Furthermore, changes in management structure or allocation methodologies and procedures may result in changes in previously reported segment financial data. During 2015 , certain organizational and methodology changes were made and, accordingly, 2014 and 2013 results have been restated and presented on a comparable basis. 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 (funds transfer pricing 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 ($ in Thousands) Corporate and Commercial Specialty Community, Consumer, and Business Risk Management and Shared Services Consolidated Total 2015 Net interest income $ 310,072 $ 349,134 $ 17,072 $ 676,278 Noninterest income 46,742 265,638 16,029 328,409 Total revenue 356,814 614,772 33,101 1,004,687 Credit provision* 41,913 25,614 (30,027 ) 37,500 Noninterest expense 141,912 492,419 63,068 697,399 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 49,213 221,379 19,727 290,319 Total revenue 345,930 531,823 93,533 971,286 Credit provision* 46,857 23,934 (54,791 ) 16,000 Noninterest expense 148,476 463,184 67,581 679,241 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 % 2013 Net interest income $ 321,346 $ 317,898 $ 6,299 $ 645,543 Noninterest income 48,417 247,667 17,015 313,099 Total revenue 369,763 565,565 23,314 958,642 Credit provision* 55,297 20,122 (65,319 ) 10,100 Noninterest expense 140,744 477,318 62,587 680,649 Income before income taxes 173,722 68,125 26,046 267,893 Income tax expense (benefit) 60,802 23,843 (5,444 ) 79,201 Net income $ 112,920 $ 44,282 $ 31,490 $ 188,692 Return on average allocated capital (ROCET1)** 12.5 % 7.8 % 6.5 % 9.8 % Segment Balance Sheet Data ($ in Thousands) Corporate and Commercial Specialty Community, Consumer, and Business Risk Management and Shared Services Consolidated Total 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 2013 Average earning assets $ 8,443,203 $ 7,225,943 $ 5,310,982 $ 20,980,128 Average loans 8,433,389 7,225,943 3,813 15,663,145 Average deposits 5,479,567 9,675,302 2,283,326 17,438,195 Average allocated capital (CET1)** $ 900,306 $ 570,634 $ 407,431 $ 1,878,371 * The consolidated credit provision is equal to the actual reported provision for credit losses. ** The Federal Reserve establishes capital adequacy requirements for the Corporation, including Tier 1 capital. Tier 1 capital is comprised of common capital and certain redeemable, non-cumulative preferred stock. Average allocated capital represents average common equity Tier 1 which is defined as average Tier 1 capital excluding qualifying perpetual preferred stock and qualifying trust preferred securities. This is a non-GAAP financial measure. For segment reporting purposes, the ROCET1 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, 2015
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Accumulated Other Comprehensive Income (Loss)	NOTE 22 ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS): The following table summarizes the components of accumulated other comprehensive income (loss) at December 31, 2015 , 2014 , and 2013 , changes during the years then ended, and reclassifications out of accumulated other comprehensive income (loss) during the years ended December 31, 2015 , 2014 , and 2013 , respectively. Investments Securities Available For Sale Defined Benefit Pension and Post Retirement Obligations Accumulated Other Comprehensive Income (Loss) Balance December 31, 2012 $ 86,109 $ (37,506 ) $ 48,603 Other comprehensive income (loss) before reclassifications (158,207 ) 35,804 (122,403 ) Amounts reclassified from accumulated other comprehensive income (loss): Investment securities gain, net (564 ) — (564 ) Personnel expense — 4,416 4,416 Income tax (expense) benefit 61,266 (15,562 ) 45,704 Net other comprehensive income (loss) during period (97,505 ) 24,658 (72,847 ) 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 )

Summary of Significant Accoun31

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2015
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. During the third quarter of 2015, the Corporation reclassified all closed end first lien home equity loans to residential mortgage loans in order to better align with the Corporation's regulatory reporting of residential mortgage loan products. All prior periods have been restated to reflect this change.
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	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. 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. 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. All restructured loans are disclosed as restructured loans in the calendar year of restructuring. In subsequent years, a restructured loan modified at a market rate that has performed according to the modified terms for at least six months will cease being disclosed as a restructured loan. A loan that has been modified at a below market rate will return to performing status if it satisfies the six month performance requirement; however, it will remain classified as a restructured loan. See Note 4 for additional information on restructured loans.
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. At December 31, 2015 , the carrying value of loans held for sale included a market valuation adjustment of $155,000 , while at December 31, 2014 , there was no market valuation adjustment to loans held for sale.
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. 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. 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, installment loans and credit cards, are collectively evaluated for impairment. Interest income on impaired loans 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. 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 and 14 years for 2015 and 2014, respectively). 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, 2015 and 2014 , 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, 2015 and 2014 , 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. Beginning with the 2014 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 post-retirement 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 June 2015, 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, 2015. The amendments that require transition guidance are not applicable to the Corporation. All other amendments were effective upon the issuance of this update in June 2015. The Corporation adopted the accounting standard during the second quarter of 2015, as required, with no material impact on its results of operations, financial position, or liquidity. In May 2015, the FASB issued an amendment to its current guidance regarding pushdown accounting for newly acquired businesses. The amendment eliminates the SEC guidance on pushdown accounting from the Accounting Standards Codification. The amendments align the FASB’s codification with the related material in the SEC's staff accounting bulletin (SAB) No. 115. SAB 115 rescinds portions of the interpretive guidance included in the SEC's Staff Accounting Bulletins series and brings existing guidance into conformity with ASU 2014-17, Pushdown Accounting, which provides an acquired entity with an option to apply pushdown accounting in its separate financial statements upon occurrence of an event in which an acquirer obtains control of the acquired entity. The Corporation adopted the accounting standard during the second quarter of 2015, as required, with no material impact on its results of operations, financial position, or liquidity. In August 2014, the FASB issued an amendment to clarify how creditors are to classify certain government-guaranteed mortgage loans upon foreclosure. This amendment requires that a mortgage loan be derecognized and a separate other receivable be recognized upon foreclosure if the following conditions are met: (1) the loan has a government guarantee that is not separate from the loan before foreclosure and (2) at the time of foreclosure, the creditor has the intent to convey the real estate property to the guarantor and make a claim on the guarantee, and the creditor has the ability to recover under the claim and (3) at the time of foreclosure, any amount of the claim that is determined on the basis of the fair value of the real estate is fixed. Upon foreclosure, the separate other receivable should be measured based on the amount of the loan balance (principal and interest) expected to be recovered from the guarantor. This amendment was effective for annual reporting periods, including interim periods within those annual periods, beginning after December 15, 2014. The Corporation adopted the accounting standard on a prospective basis during the first quarter of 2015, as required, with no material impact on its results of operations, financial position, or liquidity. In June 2014, the FASB issued an amendment to clarify the current accounting and disclosures for certain repurchase agreements. The amendments in this update require two accounting changes: (1) change the accounting for repurchase-to-maturity transactions to secured borrowing accounting and (2) require separate accounting for a transfer of a financial asset executed contemporaneously with a repurchase agreement with the same counterparty, which will result in secured borrowing accounting for the repurchase agreement. The amendments in this update also require additional disclosures for certain transactions on the transfer of financial assets, as well as new disclosures for repurchase agreements, securities lending transactions, and repurchase-to-maturity transactions that are accounted for as secured borrowings. This amendment was effective for public business entities for the first interim or annual period beginning after December 15, 2014. The Corporation adopted the accounting standard during the first quarter of 2015, as required, with no material impact on its results of operations, financial position, or liquidity. See Note 8 for the new repurchase agreement disclosures. In January 2014, the FASB issued an amendment to clarify that an in substance repossession or foreclosure occurs, and a creditor is considered to have received physical possession of residential real estate property collateralizing a consumer mortgage loan, upon either (1) the creditor obtaining legal title to the residential real estate property upon completion of a foreclosure or (2) the borrower conveying all interest in the residential real estate property to the creditor to satisfy that loan through completion of a deed in lieu of foreclosure or through a similar agreement. In addition, the amendments require interim and annual disclosure of both the amount of foreclosed residential real estate property held by the creditor and the recorded investment in consumer mortgage loans collateralized by residential real estate property that are in the process of foreclosure in accordance with local requirements of the applicable jurisdiction. This amendment was effective for fiscal years, and interim periods within those years, beginning after December 15, 2014. The Corporation adopted the accounting standard using the prospective transition method during the first quarter of 2015, as required, with no material impact on its results of operations, financial position, or liquidity. In January 2014, the FASB issued an amendment which permits reporting entities to make an accounting policy election to account for their investments in qualified affordable housing projects using the proportional amortization method if certain conditions are met. Under the proportional amortization method, an entity amortizes the initial cost of the investment in proportion to the tax credits and other tax benefits received and recognizes the net investment performance in the income statement as a component of income tax expense (benefit). For those investments in qualified affordable housing projects not accounted for using the proportional method, the investment should be accounted for as an equity method investment or a cost method investment. The decision to apply the proportional amortization method of accounting is an accounting policy decision that should be applied consistently to all qualifying affordable housing project investments rather than a decision to be applied to individual investments. This amendment should be applied retrospectively to all periods presented. A reporting entity that uses the effective yield method to account for its investments in qualified affordable housing projects before the date of adoption may continue to apply the effective yield method for those preexisting investments. This amendment was effective for fiscal years, and interim periods within those years, beginning after December 15, 2014. The Corporation made an accounting policy election to use the proportional amortization method for investments in qualified affordable housing projects during the first quarter of 2015, which had no material impact on its results of operations, financial position, or liquidity.

Investment Securities (Tables)

Investment Securities (Tables)	12 Months Ended
	Dec. 31, 2015
Investments, Debt and Equity Securities [Abstract]
Investment securities available for sale	December 31, 2015 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses 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: Obligations of state and political subdivisions (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 December 31, 2014 Amortized Gross Gross Fair Value ($ in Thousands) Investment securities available for sale: U. S. Treasury securities $ 999 $ — $ (1 ) $ 998 Municipal securities 560,839 21,869 (29 ) 582,679 Residential mortgage-related securities: FNMA / FHLMC 3,534,240 59,640 (30,423 ) 3,563,457 GNMA 165,863 1,596 (127 ) 167,332 Private-label 2,297 7 (10 ) 2,294 GNMA commercial mortgage-related securities 1,097,913 1,922 (25,942 ) 1,073,893 Other securities (debt and equity) 6,108 51 — 6,159 Total investment securities available for sale $ 5,368,259 $ 85,085 $ (56,532 ) $ 5,396,812 Investment securities held to maturity: Municipal securities $ 404,455 $ 9,444 $ (832 ) $ 413,067 Total investment securities held to maturity $ 404,455 $ 9,444 $ (832 ) $ 413,067
Investment securities held to maturity	December 31, 2015 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses 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: Obligations of state and political subdivisions (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 December 31, 2014 Amortized Gross Gross Fair Value ($ in Thousands) Investment securities available for sale: U. S. Treasury securities $ 999 $ — $ (1 ) $ 998 Municipal securities 560,839 21,869 (29 ) 582,679 Residential mortgage-related securities: FNMA / FHLMC 3,534,240 59,640 (30,423 ) 3,563,457 GNMA 165,863 1,596 (127 ) 167,332 Private-label 2,297 7 (10 ) 2,294 GNMA commercial mortgage-related securities 1,097,913 1,922 (25,942 ) 1,073,893 Other securities (debt and equity) 6,108 51 — 6,159 Total investment securities available for sale $ 5,368,259 $ 85,085 $ (56,532 ) $ 5,396,812 Investment securities held to maturity: Municipal securities $ 404,455 $ 9,444 $ (832 ) $ 413,067 Total investment securities held to maturity $ 404,455 $ 9,444 $ (832 ) $ 413,067
Amortized cost and fair values of investment securities available for sale by contractual maturity	Available for Sale Held to Maturity ($ in Thousands) Amortized Cost Fair Value Amortized Cost Fair Value Due in one year or less $ 1,500 $ 1,515 $ 42,841 $ 26,761 Due after one year through five years 4,199 4,197 244,257 255,899 Due after five years through ten years — — 253,429 261,934 Due after ten years — — 503,240 515,637 Total debt securities 5,699 5,712 1,043,767 1,060,231 Residential mortgage-related securities: FNMA / FHLMC 1,388,995 1,414,626 41,469 41,337 GNMA 1,605,956 1,590,003 82,994 82,874 Private-label 1,722 1,709 — — GNMA commercial mortgage-related securities 1,982,477 1,955,310 — — Equity securities 18 54 — — Total investment securities $ 4,984,867 $ 4,967,414 $ 1,168,230 $ 1,184,442 Ratio of Fair Value to Amortized Cost 99.6 % 101.4 %
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 2015 , 2014 , or 2013 . 2015 2014 2013 ($ in Thousands) Gross gains $ 12,270 $ 1,184 $ 637 Gross losses (4,137 ) (690 ) (73 ) Investment securities gains, net $ 8,133 $ 494 $ 564 Proceeds from sales of investment securities $ 1,601,947 $ 102,011 $ 136,152
Unrealized losses and fair value of available for sale and held to maturity securities, by investment category and time length	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, 2014 . Less than 12 months 12 months or more Total December 31, 2014 Number Unrealized Fair Number Unrealized Fair Unrealized Fair ($ in Thousands) Investment securities available for sale: U.S. Treasury securities 1 $ (1 ) $ 998 — $ — $ — $ (1 ) $ 998 Municipal securities 6 (9 ) 3,374 6 (20 ) 2,133 (29 ) 5,507 Residential mortgage-related securities: FNMA / FHLMC 15 (1,395 ) 330,839 52 (29,028 ) 1,246,093 (30,423 ) 1,576,932 GNMA 1 (9 ) 2,874 4 (118 ) 10,440 (127 ) 13,314 Private-label 1 (9 ) 1,772 2 (1 ) 27 (10 ) 1,799 GNMA commercial mortgage-related securities 9 (1,766 ) 329,982 20 (24,176 ) 460,425 (25,942 ) 790,407 Total 33 $ (3,189 ) $ 669,839 84 $ (53,343 ) $ 1,719,118 $ (56,532 ) $ 2,388,957 Investment securities held to maturity: Municipal securities 74 $ (216 ) $ 31,924 85 $ (616 ) $ 38,915 $ (832 ) $ 70,839 Total 74 $ (216 ) $ 31,924 85 $ (616 ) $ 38,915 $ (832 ) $ 70,839 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, 2015 . Less than 12 months 12 months or more Total December 31, 2015 Number of Securities Unrealized Losses Fair Value Number of Securities Unrealized Losses Fair Value Unrealized Losses Fair Value ($ in Thousands) Investment securities available for sale: U.S. Treasury securities 1 $ (2 ) $ 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, 2015
Financing Receivable, Impaired [Line Items]
Loan composition	Loans at December 31 are summarized below. 2015 2014 ($ in Thousands) Commercial and industrial $ 6,147,440 $ 5,905,902 Commercial real estate — owner occupied 918,212 1,007,937 Lease financing 43,243 51,529 Commercial and business lending 7,108,895 6,965,368 Commercial real estate — investor 3,234,266 3,056,485 Real estate construction 1,162,145 1,008,956 Commercial real estate lending 4,396,411 4,065,441 Total commercial 11,505,306 11,030,809 Home equity 1,005,802 1,051,927 Installment and credit cards 419,968 454,219 Residential mortgage 5,783,267 5,056,891 Total consumer 7,209,037 6,563,037 Total loans $ 18,714,343 $ 17,593,846
Loans receivable related parties	These loans to related parties are summarized below. 2015 ($ in Thousands) Balance at beginning of year $ 74,420 New loans 14,840 Repayments (19,990 ) Changes due to status of executive officers and directors (32,673 ) Balance at end of year $ 36,597
Changes in the allowance for loan losses	A summary of the changes in the allowance for credit losses for the years indicated was as follows. 2015 2014 2013 ($ in Thousands) Allowance for Loan Losses: Balance at beginning of year $ 266,302 $ 268,315 $ 297,409 Provision for loan losses 38,000 13,000 10,000 Charge offs (52,280 ) (44,096 ) (88,061 ) Recoveries 22,242 29,083 48,967 Net charge offs (30,038 ) (15,013 ) (39,094 ) Balance at end of year $ 274,264 $ 266,302 $ 268,315 Allowance for Unfunded Commitments: Balance at beginning of year $ 24,900 $ 21,900 $ 21,800 Provision for unfunded commitments (500 ) 3,000 100 Balance at end of year $ 24,400 $ 24,900 $ 21,900 Allowance for Credit Losses $ 298,664 $ 291,202 $ 290,215
Changes in the allowance for loan losses by portfolio segment	For comparison purposes, a summary of the changes in the allowance for loan losses by portfolio segment for the year ended December 31, 2014 , was as follows. $ in Thousands Commercial and industrial Commercial real estate — owner occupied Lease financing Commercial real estate — investor Real estate construction Home equity Installment and credit cards Residential mortgage Total Balance at Dec 31, 2013 $ 104,501 $ 19,476 $ 1,607 $ 58,156 $ 23,418 $ 27,932 $ 2,416 $ 30,809 $ 268,315 Provision for loan losses 14,767 (1,296 ) 35 (17,290 ) (1,277 ) 6,278 6,279 5,504 13,000 Charge offs (14,633 ) (3,476 ) (39 ) (4,529 ) (1,958 ) (10,946 ) (2,876 ) (5,639 ) (44,096 ) Recoveries 11,390 1,806 7 9,996 816 3,200 616 1,252 29,083 Balance at Dec 31, 2014 $ 116,025 $ 16,510 $ 1,610 $ 46,333 $ 20,999 $ 26,464 $ 6,435 $ 31,926 $ 266,302 Allowance for loan losses: Ending balance impaired loans individually evaluated for impairment $ 13,615 $ 1,490 $ 574 $ 1,649 $ 328 $ 11 $ — $ 199 $ 17,866 Ending balance impaired loans collectively evaluated for impairment $ 2,852 $ 1,731 $ — $ 1,938 $ 767 $ 11,371 $ 308 $ 13,598 $ 32,565 Total impaired loans $ 16,467 $ 3,221 $ 574 $ 3,587 $ 1,095 $ 11,382 $ 308 $ 13,797 $ 50,431 Ending balance all other loans collectively evaluated for impairment $ 99,558 $ 13,289 $ 1,036 $ 42,746 $ 19,904 $ 15,082 $ 6,127 $ 18,129 $ 215,871 Total $ 116,025 $ 16,510 $ 1,610 $ 46,333 $ 20,999 $ 26,464 $ 6,435 $ 31,926 $ 266,302 Loans: Ending balance impaired loans individually evaluated for impairment $ 45,118 $ 20,731 $ 1,801 $ 19,683 $ 3,776 $ 962 $ — $ 9,751 $ 101,822 Ending balance impaired loans collectively evaluated for impairment $ 38,437 $ 15,548 $ — $ 26,129 $ 2,350 $ 23,698 $ 1,587 $ 66,058 $ 173,807 Total impaired loans $ 83,555 $ 36,279 $ 1,801 $ 45,812 $ 6,126 $ 24,660 $ 1,587 $ 75,809 $ 275,629 Ending balance all other loans collectively evaluated for impairment $ 5,822,347 $ 971,658 $ 49,728 $ 3,010,673 $ 1,002,830 $ 1,027,267 $ 452,632 $ 4,981,082 $ 17,318,217 Total $ 5,905,902 $ 1,007,937 $ 51,529 $ 3,056,485 $ 1,008,956 $ 1,051,927 $ 454,219 $ 5,056,891 $ 17,593,846 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 Lease financing Commercial real estate — investor Real estate construction Home equity Installment and credit cards Residential mortgage Total Balance at Dec 31, 2014 $ 116,025 $ 16,510 $ 1,610 $ 46,333 $ 20,999 $ 26,464 $ 6,435 $ 31,926 $ 266,302 Provision for loan losses 30,861 3,894 (671 ) (2,827 ) 2,749 906 2,194 894 38,000 Charge offs (27,687 ) (2,645 ) — (4,645 ) (750 ) (7,048 ) (3,869 ) (5,636 ) (52,280 ) Recoveries 9,795 921 26 4,157 2,268 3,233 765 1,077 22,242 Balance at Dec 31, 2015 $ 128,994 $ 18,680 $ 965 $ 43,018 $ 25,266 $ 23,555 $ 5,525 $ 28,261 $ 274,264 Allowance for loan losses: Ending balance impaired loans individually evaluated for impairment $ 7,522 $ — $ — $ 229 $ — $ 46 $ — $ 166 $ 7,963 Ending balance impaired loans collectively evaluated for impairment $ 640 $ 448 $ — $ 1,602 $ 453 $ 10,072 $ 195 $ 12,296 $ 25,706 Total impaired loans $ 8,162 $ 448 $ — $ 1,831 $ 453 $ 10,118 $ 195 $ 12,462 $ 33,669 Ending balance all other loans collectively evaluated for impairment $ 120,832 $ 18,232 $ 965 $ 41,187 $ 24,813 $ 13,437 $ 5,330 $ 15,799 $ 240,595 Total $ 128,994 $ 18,680 $ 965 $ 43,018 $ 25,266 $ 23,555 $ 5,525 $ 28,261 $ 274,264 Loans: Ending balance impaired loans individually evaluated for impairment $ 89,935 $ 6,221 $ 1,634 $ 5,460 $ — $ 1,281 $ — $ 6,956 $ 111,487 Ending balance impaired loans collectively evaluated for impairment $ 31,299 $ 9,705 $ — $ 25,098 $ 1,450 $ 21,032 $ 1,154 $ 64,396 $ 154,134 Total impaired loans $ 121,234 $ 15,926 $ 1,634 $ 30,558 $ 1,450 $ 22,313 $ 1,154 $ 71,352 $ 265,621 Ending balance all other loans collectively evaluated for impairment $ 6,026,206 $ 902,286 $ 41,609 $ 3,203,708 $ 1,160,695 $ 983,489 $ 418,814 $ 5,711,915 $ 18,448,722 Total $ 6,147,440 $ 918,212 $ 43,243 $ 3,234,266 $ 1,162,145 $ 1,005,802 $ 419,968 $ 5,783,267 $ 18,714,343
Summarized details of Loans	The following table presents loans by past due status at December 31, 2015 . 30-59 Days Past Due 60-89 Days Past Due 90 Days or More Past Due* Total Past Due Current Total ($ in Thousands) Accruing loans Commercial and industrial $ 602 $ 409 $ 249 $ 1,260 $ 6,054,239 $ 6,055,499 Commercial real estate — owner occupied 7,142 — — 7,142 903,021 910,163 Lease financing — — — — 41,609 41,609 Commercial and business lending 7,744 409 249 8,402 6,998,869 7,007,271 Commercial real estate — investor 291 — — 291 3,225,332 3,225,623 Real estate construction 270 26 — 296 1,160,909 1,161,205 Commercial real estate lending 561 26 — 587 4,386,241 4,386,828 Total commercial 8,305 435 249 8,989 11,385,110 11,394,099 Home equity 6,190 1,729 — 7,919 982,639 990,558 Installment and credit cards 1,195 675 1,399 3,269 416,374 419,643 Residential mortgage 4,491 439 — 4,930 5,726,855 5,731,785 Total consumer 11,876 2,843 1,399 16,118 7,125,868 7,141,986 Total accruing loans $ 20,181 $ 3,278 $ 1,648 $ 25,107 $ 18,510,978 $ 18,536,085 Nonaccrual loans Commercial and industrial $ 895 $ 16 $ 4,848 $ 5,759 $ 86,182 $ 91,941 Commercial real estate — owner occupied — 2,572 1,301 3,873 4,176 8,049 Lease financing — — — — 1,634 1,634 Commercial and business lending 895 2,588 6,149 9,632 91,992 101,624 Commercial real estate — investor 3,174 1,158 3,480 7,812 831 8,643 Real estate construction 133 61 427 621 319 940 Commercial real estate lending 3,307 1,219 3,907 8,433 1,150 9,583 Total commercial 4,202 3,807 10,056 18,065 93,142 111,207 Home equity 1,922 1,330 5,833 9,085 6,159 15,244 Installment and credit cards 47 39 151 237 88 325 Residential mortgage 3,984 5,251 17,950 27,185 24,297 51,482 Total consumer 5,953 6,620 23,934 36,507 30,544 67,051 Total nonaccrual loans** $ 10,155 $ 10,427 $ 33,990 $ 54,572 $ 123,686 $ 178,258 Total loans Commercial and industrial $ 1,497 $ 425 $ 5,097 $ 7,019 $ 6,140,421 $ 6,147,440 Commercial real estate — owner occupied 7,142 2,572 1,301 11,015 907,197 918,212 Lease financing — — — — 43,243 43,243 Commercial and business lending 8,639 2,997 6,398 18,034 7,090,861 7,108,895 Commercial real estate — investor 3,465 1,158 3,480 8,103 3,226,163 3,234,266 Real estate construction 403 87 427 917 1,161,228 1,162,145 Commercial real estate lending 3,868 1,245 3,907 9,020 4,387,391 4,396,411 Total commercial 12,507 4,242 10,305 27,054 11,478,252 11,505,306 Home equity 8,112 3,059 5,833 17,004 988,798 1,005,802 Installment and credit cards 1,242 714 1,550 3,506 416,462 419,968 Residential mortgage 8,475 5,690 17,950 32,115 5,751,152 5,783,267 Total consumer 17,829 9,463 25,333 52,625 7,156,412 7,209,037 Total loans $ 30,336 $ 13,705 $ 35,638 $ 79,679 $ 18,634,664 $ 18,714,343 * The recorded investment in loans past due 90 days or more and still accruing totaled $2 million at December 31, 2015 (the same as the reported balances for the accruing loans noted above). ** The percent of nonaccrual loans which are current was 69% at December 31, 2015 . The following table presents loans by past due status at December 31, 2014 . 30-59 Days Past Due 60-89 Days Past Due 90 Days or More Past Due* Total Past Due Current Total ($ in Thousands) Accruing loans Commercial and industrial $ 4,466 $ 10,281 $ 254 $ 15,001 $ 5,841,238 $ 5,856,239 Commercial real estate — owner occupied 8,429 2,199 — 10,628 971,484 982,112 Lease financing — — — — 49,728 49,728 Commercial and business lending 12,895 12,480 254 25,629 6,862,450 6,888,079 Commercial real estate — investor 712 496 — 1,208 3,032,592 3,033,800 Real estate construction 951 33 — 984 1,002,573 1,003,557 Commercial real estate lending 1,663 529 — 2,192 4,035,165 4,037,357 Total commercial 14,558 13,009 254 27,821 10,897,615 10,925,436 Home equity 6,988 1,795 52 8,835 1,026,641 1,035,476 Installment and credit cards 1,186 746 1,317 3,249 450,357 453,606 Residential mortgage 3,889 957 — 4,846 4,997,069 5,001,915 Total consumer 12,063 3,498 1,369 16,930 6,474,067 6,490,997 Total accruing loans $ 26,621 $ 16,507 $ 1,623 $ 44,751 $ 17,371,682 $ 17,416,433 Nonaccrual loans Commercial and industrial $ 872 $ 627 $ 10,154 $ 11,653 $ 38,010 $ 49,663 Commercial real estate — owner occupied 3,197 41 8,596 11,834 13,991 25,825 Lease financing — — 513 513 1,288 1,801 Commercial and business lending 4,069 668 19,263 24,000 53,289 77,289 Commercial real estate — investor 1,857 459 12,765 15,081 7,604 22,685 Real estate construction 87 73 798 958 4,441 5,399 Commercial real estate lending 1,944 532 13,563 16,039 12,045 28,084 Total commercial 6,013 1,200 32,826 40,039 65,334 105,373 Home equity 1,471 1,766 6,840 10,077 6,374 16,451 Installment and credit cards 96 39 141 276 337 613 Residential mortgage 5,172 3,193 23,492 31,857 23,119 54,976 Total consumer 6,739 4,998 30,473 42,210 29,830 72,040 Total nonaccrual loans** $ 12,752 $ 6,198 $ 63,299 $ 82,249 $ 95,164 $ 177,413 Total loans Commercial and industrial $ 5,338 $ 10,908 $ 10,408 $ 26,654 $ 5,879,248 $ 5,905,902 Commercial real estate — owner occupied 11,626 2,240 8,596 22,462 985,475 1,007,937 Lease financing — — 513 513 51,016 51,529 Commercial and business lending 16,964 13,148 19,517 49,629 6,915,739 6,965,368 Commercial real estate — investor 2,569 955 12,765 16,289 3,040,196 3,056,485 Real estate construction 1,038 106 798 1,942 1,007,014 1,008,956 Commercial real estate lending 3,607 1,061 13,563 18,231 4,047,210 4,065,441 Total commercial 20,571 14,209 33,080 67,860 10,962,949 11,030,809 Home equity 8,459 3,561 6,892 18,912 1,033,015 1,051,927 Installment and credit cards 1,282 785 1,458 3,525 450,694 454,219 Residential mortgage 9,061 4,150 23,492 36,703 5,020,188 5,056,891 Total consumer 18,802 8,496 31,842 59,140 6,503,897 6,563,037 Total loans $ 39,373 $ 22,705 $ 64,922 $ 127,000 $ 17,466,846 $ 17,593,846 * The recorded investment in loans past due 90 days or more and still accruing totaled $2 million at December 31, 2014 (the same as the reported balances for the accruing loans noted above). ** The percent of nonaccrual loans which are current was 54% at December 31, 2014 .
Summarized details of impaired Loans	The following table presents impaired loans at December 31, 2015 . Recorded Investment Unpaid Principal Balance Related Allowance Average Recorded Investment Interest Income Recognized* ($ 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 Lease financing — — — — — 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 Home equity 21,769 23,989 10,118 22,624 1,147 Installment and credit cards 1,154 1,225 195 1,199 30 Residential mortgage 66,590 71,084 12,462 68,183 2,374 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 $ 63,449 $ 70,625 $ — $ 77,666 $ 1,657 Commercial real estate — owner occupied 6,221 6,648 — 6,534 15 Lease financing 1,634 1,634 — 1,907 — 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 Home equity 544 544 — 544 30 Installment and credit cards — — — — — Residential mortgage 4,762 5,033 — 4,726 126 Total consumer 5,306 5,577 — 5,270 156 Total loans $ 79,346 $ 87,324 $ — $ 94,140 $ 1,918 Total Commercial and industrial $ 121,234 $ 130,034 $ 8,162 $ 124,499 $ 2,512 Commercial real estate — owner occupied 15,926 16,452 448 16,621 427 Lease financing 1,634 1,634 — 1,907 — 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 Home equity 22,313 24,533 10,118 23,168 1,177 Installment and credit cards 1,154 1,225 195 1,199 30 Residential mortgage 71,352 76,117 12,462 72,909 2,500 Total consumer 94,819 101,875 22,775 97,276 3,707 Total loans** $ 265,621 $ 284,433 $ 33,669 $ 273,011 $ 8,716 * Interest income recognized included $4 million of interest income recognized on accruing restructured loans for the year ended December 31, 2015 . ** The net recorded investment (defined as recorded investment, net of the related allowance) of the impaired loans represented 82% of the unpaid principal balance at December 31, 2015. The following table presents impaired loans at December 31, 2014 . Recorded Investment Unpaid Principal Balance Related Allowance Average Recorded Investment Interest Income Recognized* ($ in Thousands) Loans with a related allowance Commercial and industrial $ 76,433 $ 80,414 $ 16,467 $ 80,004 $ 3,139 Commercial real estate — owner occupied 19,839 21,807 3,221 20,878 681 Lease financing 1,801 1,801 574 2,009 — Commercial and business lending 98,073 104,022 20,262 102,891 3,820 Commercial real estate — investor 36,841 40,869 3,587 38,657 1,250 Real estate construction 3,043 5,910 1,095 3,818 105 Commercial real estate lending 39,884 46,779 4,682 42,475 1,355 Total commercial 137,957 150,801 24,944 145,366 5,175 Home equity 23,874 26,585 11,382 25,087 1,257 Installment and credit cards 1,587 1,795 308 1,736 58 Residential mortgage 68,748 74,005 13,797 70,030 2,307 Total consumer 94,209 102,385 25,487 96,853 3,622 Total loans $ 232,166 $ 253,186 $ 50,431 $ 242,219 $ 8,797 Loans with no related allowance Commercial and industrial $ 7,122 $ 12,634 $ — $ 8,851 $ 82 Commercial real estate — owner occupied 16,440 19,019 — 17,970 219 Commercial and business lending 23,562 31,653 — 26,821 301 Commercial real estate — investor 8,971 14,036 — 10,014 133 Real estate construction 3,083 3,815 — 3,241 — Commercial real estate lending 12,054 17,851 — 13,255 133 Total commercial 35,616 49,504 — 40,076 434 Home equity 786 806 — 851 18 Installment and credit cards — — — — — Residential mortgage 7,061 7,315 — 7,224 135 Total consumer 7,847 8,121 — 8,075 153 Total loans $ 43,463 $ 57,625 $ — $ 48,151 $ 587 Total Commercial and industrial $ 83,555 $ 93,048 $ 16,467 $ 88,855 $ 3,221 Commercial real estate — owner occupied 36,279 40,826 3,221 38,848 900 Lease financing 1,801 1,801 574 2,009 — Commercial and business lending 121,635 135,675 20,262 129,712 4,121 Commercial real estate — investor 45,812 54,905 3,587 48,671 1,383 Real estate construction 6,126 9,725 1,095 7,059 105 Commercial real estate lending 51,938 64,630 4,682 55,730 1,488 Total commercial 173,573 200,305 24,944 185,442 5,609 Home equity 24,660 27,391 11,382 25,938 1,275 Installment and credit cards 1,587 1,795 308 1,736 58 Residential mortgage 75,809 81,320 13,797 77,254 2,442 Total consumer 102,056 110,506 25,487 104,928 3,775 Total loans** $ 275,629 $ 310,811 $ 50,431 $ 290,370 $ 9,384 * Interest income recognized included $5 million of interest income recognized on accruing restructured loans for the year ended December 31, 2014 . ** The net recorded investment (defined as recorded investment, net of the related allowance) of the impaired loans represented 72% of of the unpaid principal balance at December 31, 2014.
Nonaccrual and Performing Restructured Loans	The following table presents nonaccrual and performing restructured loans by loan portfolio. December 31, 2015 December 31, 2014 December 31, 2013 Performing Restructured Loans Nonaccrual Restructured Loans* Performing Restructured Loans Nonaccrual Restructured Loans* Performing Restructured Loans Nonaccrual Restructured Loans* ($ in Thousands) Commercial and industrial $ 29,293 $ 1,714 $ 33,892 $ 3,260 $ 32,517 $ 6,900 Commercial real estate — owner occupied 7,877 2,703 10,454 5,656 13,009 10,999 Commercial real estate — investor 21,915 3,936 23,127 15,216 44,946 18,069 Real estate construction 510 177 727 2,438 3,793 2,065 Home equity 7,069 4,522 8,209 4,838 8,197 4,441 Installment and credit cards 829 40 974 199 246 451 Residential mortgage 19,870 24,592 20,833 26,049 21,277 16,660 $ 87,363 $ 37,684 $ 98,216 $ 57,656 $ 123,985 $ 59,585 * 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, 2015 , 2014 and 2013 , respectively, and the recorded investment and unpaid principal balance as of December 31, 2015 , 2014 and 2013 , respectively. Year Ended December 31, 2015 Year Ended December 31, 2014 Year Ended December 31, 2013 Number of Loans Recorded Investment(1) Unpaid Principal Balance(2) Number of Loans Recorded Investment(1) Unpaid Principal Balance(2) Number of Loans Recorded Investment(1) Unpaid Principal Balance(2) ($ in Thousands) Commercial and industrial 12 $ 2,219 $ 2,900 15 $ 7,681 $ 7,711 48 $ 11,833 $ 14,543 Commercial real estate — owner occupied 5 3,694 3,901 4 1,465 1,625 12 8,823 9,035 Commercial real estate — investor 5 21,573 21,640 6 6,097 6,521 25 26,480 28,516 Real estate construction 4 78 79 2 15 15 9 1,822 1,961 Home equity 88 3,103 3,249 117 3,913 4,308 82 3,991 4,242 Installment and credit cards — — — 2 24 26 3 193 200 Residential mortgage 97 10,464 10,996 163 19,675 20,454 99 10,910 12,822 211 $ 41,131 $ 42,765 309 $ 38,870 $ 40,660 278 $ 64,052 $ 71,319 (1) Represents post-modification outstanding recorded investment. (2) 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 12 months which subsequently defaulted during the years ended December 31, 2015 , 2014 , and 2013 , respectively, as well as the recorded investment in these restructured loans as of December 31, 2015 , 2014 , and 2013 , respectively. Year Ended December 31, 2015 Year Ended December 31, 2014 Year Ended December 31, 2013 Number of Loans Recorded Investment Number of Loans Recorded Investment Number of Loans Recorded Investment ($ in Thousands) Commercial and industrial 2 $ 197 1 $ 52 15 $ 1,493 Commercial real estate — owner occupied — — 3 785 4 542 Commercial real estate — investor — — 13 6,200 4 1,784 Real estate construction — — 1 160 4 80 Home equity 28 1,220 54 1,802 11 829 Installment and credit cards — — 3 34 — — Residential mortgage 61 6,815 80 10,032 26 4,528 91 $ 8,232 155 $ 19,065 64 $ 9,256
Commercial Loan [Member]
Financing Receivable, Impaired [Line Items]
Commercial and Consumer loans by credit quality indicator	The following table presents commercial loans by credit quality indicator at December 31, 2014 . Pass Special Mention Potential Problem Impaired Total ($ Thousands) Commercial and industrial $ 5,594,497 $ 119,328 $ 108,522 $ 83,555 $ 5,905,902 Commercial real estate — owner occupied 904,526 18,437 48,695 36,279 1,007,937 Lease financing 46,931 88 2,709 1,801 51,529 Commercial and business lending 6,545,954 137,853 159,926 121,635 6,965,368 Commercial real estate — investor 2,974,493 12,137 24,043 45,812 3,056,485 Real estate construction 998,972 2,082 1,776 6,126 1,008,956 Commercial real estate lending 3,973,465 14,219 25,819 51,938 4,065,441 Total commercial $ 10,519,419 $ 152,072 $ 185,745 $ 173,573 $ 11,030,809 The following table presents commercial loans by credit quality indicator at December 31, 2015 . Pass Special Mention Potential Problem Impaired Total ($ Thousands) Commercial and industrial $ 5,455,573 $ 339,953 $ 230,680 $ 121,234 $ 6,147,440 Commercial real estate — owner occupied 827,694 38,886 35,706 15,926 918,212 Lease financing 37,969 1,190 2,450 1,634 43,243 Commercial and business lending 6,321,236 380,029 268,836 138,794 7,108,895 Commercial real estate — investor 3,150,134 27,630 25,944 30,558 3,234,266 Real estate construction 1,156,524 252 3,919 1,450 1,162,145 Commercial real estate lending 4,306,658 27,882 29,863 32,008 4,396,411 Total commercial $ 10,627,894 $ 407,911 $ 298,699 $ 170,802 $ 11,505,306
Consumer Loan [Member]
Financing Receivable, Impaired [Line Items]
Commercial and Consumer loans by credit quality indicator	The following table presents consumer loans by credit quality indicator at December 31, 2015 . Performing 30-89 Days Past Due Potential Problem Impaired Total ($ Thousands) Home equity $ 975,348 $ 7,919 $ 222 $ 22,313 $ 1,005,802 Installment and credit cards 416,944 1,870 — 1,154 419,968 Residential mortgage 5,704,189 4,930 2,796 71,352 5,783,267 Total consumer $ 7,096,481 $ 14,719 $ 3,018 $ 94,819 $ 7,209,037 The following table presents consumer loans by credit quality indicator at December 31, 2014 . Performing 30-89 Days Past Due Potential Problem Impaired Total ($ Thousands) Home equity $ 1,017,604 $ 8,783 $ 880 $ 24,660 $ 1,051,927 Installment and credit cards 450,698 1,932 2 1,587 454,219 Residential mortgage 4,972,455 4,846 3,781 75,809 5,056,891 Total consumer $ 6,440,757 $ 15,561 $ 4,663 $ 102,056 $ 6,563,037

Goodwill and Intangible Assets

Goodwill and Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2015
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. 2015 2014 2013 ($ in Thousands) Core deposit intangibles: Gross carrying amount $ 19,545 $ 36,230 $ 36,230 Accumulated amortization (19,152 ) (34,433 ) (31,565 ) Net book value $ 393 $ 1,797 $ 4,665 Amortization during the year $ 1,404 $ 2,868 $ 3,122 Other intangibles: Gross carrying amount $ 31,398 $ 19,283 $ 19,283 Accumulated amortization (15,333 ) (13,643 ) (12,764 ) Net book value $ 16,065 $ 5,640 $ 6,519 Additions during the period $ 12,115 $ — $ — Amortization during the year $ 1,690 $ 879 $ 921
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. 2015 2014 2013 ($ in Thousands) Mortgage servicing rights Mortgage servicing rights at beginning of year $ 61,379 $ 64,193 $ 61,425 Additions 12,372 8,253 18,256 Amortization (11,601 ) (11,067 ) (15,488 ) Mortgage servicing rights at end of year $ 62,150 $ 61,379 $ 64,193 Valuation allowance at beginning of year (1,234 ) (913 ) (15,476 ) (Additions) recoveries, net 425 (321 ) 14,563 Valuation allowance at end of year (809 ) (1,234 ) (913 ) Mortgage servicing rights, net $ 61,341 $ 60,145 $ 63,280 Fair value of mortgage servicing rights $ 70,686 $ 66,342 $ 74,444 Portfolio of residential mortgage loans serviced for others (“servicing portfolio”) $ 7,915,224 $ 7,999,294 $ 8,084,000 Mortgage servicing rights, net to servicing portfolio 0.77 % 0.75 % 0.78 % Mortgage servicing rights expense (1) $ 11,176 $ 11,388 $ 925 (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, 2015 . 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, 2016 $ 281 $ 1,735 $ 10,109 2017 112 1,702 8,415 2018 — 1,672 7,010 2019 — 1,373 5,894 2020 — 1,256 4,978 Beyond 2020 — 8,327 25,744 Total Estimated Amortization Expense $ 393 $ 16,065 $ 62,150

Premises and Equipment (Tables)

Premises and Equipment (Tables)	12 Months Ended
	Dec. 31, 2015
Property, Plant and Equipment [Abstract]
Summary of Premises and Equipment	A summary of premises and equipment at December 31 was as follows. 2015 2014 Estimated Useful Lives Cost Accumulated Depreciation Net Book Value Net Book Value ($ in Thousands) Land — $ 52,104 $ — $ 52,104 $ 52,790 Land improvements 3 – 15 years 11,570 4,909 6,661 6,608 Buildings 5 – 39 years 261,418 119,986 141,432 139,702 Computers 3 – 5 years 37,875 31,503 6,372 7,518 Furniture, fixtures and other equipment 3 – 15 years 159,094 109,300 49,794 55,747 Leasehold improvements 3 – 15 years 31,769 20,526 11,243 12,323 Total premises and equipment $ 553,830 $ 286,224 $ 267,606 $ 274,688
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) 2016 $ 10,417 2017 9,957 2018 8,678 2019 8,348 2020 7,583 Thereafter 17,968 Total $ 62,951

Deposits (Tables)

Deposits (Tables)	12 Months Ended
	Dec. 31, 2015
Deposits [Abstract]
Deposits by type	The distribution of deposits at December 31 was as follows. 2015 2014 ($ in Thousands) Noninterest-bearing demand deposits $ 5,562,466 $ 4,505,272 Savings deposits 1,334,420 1,235,277 Interest-bearing demand deposits 3,445,000 3,126,854 Money market deposits 9,102,977 8,324,646 Brokered certificates of deposit 42,443 42,556 Other time deposits 1,520,359 1,528,899 Total deposits $ 21,007,665 $ 18,763,504
Time deposits by maturity	Aggregate annual maturities of all time deposits at December 31, 2015 , are as follows. Maturities During Year Ending December 31, ($ in Thousands) 2016 $ 885,249 2017 161,528 2018 238,184 2019 151,161 2020 123,022 Thereafter 3,658 Total $ 1,562,802

Short-term Funding (Tables)

Short-term Funding (Tables)	12 Months Ended
	Dec. 31, 2015
Short-term Debt [Abstract]
Short-term funding	Short-term funding at December 31 was as follows. 2015 2014 ($ in Thousands) Federal funds purchased $ 47,870 $ 109,770 Securities sold under agreements to repurchase 383,568 384,221 Federal funds purchased and securities sold under agreements to repurchase 431,438 493,991 FHLB advances 335,000 500,000 Commercial paper 67,978 74,297 Other short-term funding 402,978 574,297 Total short-term funding $ 834,416 $ 1,068,288
Schedule of Repurchase Agreements	The remaining contractual maturity of the securities sold under agreements to repurchase in the consolidated balance sheets as of December 31, 2015 is presented in the following table. Remaining Contractual Maturity of the Agreements December 31, 2015 Overnight and Continuous Up to 30 days 30-90 days Greater than 90 days Total ($ in Thousands) Repurchase agreements GSE securities $ 383,568 $ — $ — $ — $ 383,568 Total $ 383,568 $ — $ — $ — $ 383,568 Gross amounts of recognized liabilities for repurchase agreements $ 383,568

Long-term Funding (Tables)

Long-term Funding (Tables)	12 Months Ended
	Dec. 31, 2015
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. 2015 2014 ($ in Thousands) FHLB advances $ 1,750,225 $ 3,000,260 Senior notes, at par 680,000 680,000 Subordinated notes, at par 250,000 250,000 Other long-term funding and capitalized costs (875 ) (143 ) Total long-term funding $ 2,679,350 $ 3,930,117
Maturities of Long-term funding	The table below summarizes the maturities of the Corporation’s long-term funding at December 31, 2015 . Year ($ in Thousands) 2016 $ 430,317 2017 27 2018 1,500,000 2019 499,617 2020 172 Thereafter 249,217 Total long-term funding $ 2,679,350

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2015
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 2015 , 2014 and 2013 . 2015 2014 2013 Dividend yield 2.00 % 2.00 % 2.00 % Risk-free interest rate 2.00 % 2.00 % 0.99 % Weighted average expected volatility 20.00 % 20.00 % 34.35 % Weighted average expected life 6 years 6 years 6 years Weighted average per share fair value of options $3.08 $3.00 $3.80
Summary of Company's Stock Option Activities	A summary of the Corporation’s stock option activity for 2015 , 2014 , and 2013 , is presented below. Stock Options Shares Weighted Average Exercise Price Weighted Average Remaining Contractual Term Aggregate Intrinsic Value (000s) Outstanding at December 31, 2012 8,640,558 $ 18.88 Granted 1,020,979 14.02 Exercised (642,202 ) 13.43 Forfeited or expired (985,092 ) 21.49 Outstanding at December 31, 2013 8,034,243 $ 18.37 6.03 $ 20,838 Options Exercisable at December 31, 2013 4,923,720 $ 21.48 4.62 $ 8,580 Granted 1,389,452 $ 17.45 Exercised (933,143 ) 13.77 Forfeited or expired (643,214 ) 23.50 Outstanding at December 31, 2014 7,847,338 $ 18.34 5.79 $ 23,986 Options Exercisable at December 31, 2014 5,076,676 $ 19.96 4.41 $ 14,953 Granted 1,348,504 $ 17.95 Exercised (1,351,646 ) 13.90 Forfeited or expired (1,215,053 ) 29.13 Outstanding at December 31, 2015 6,629,143 $ 17.22 6.24 $ 18,730 Options Exercisable at December 31, 2015 4,190,245 $ 17.25 4.93 $ 14,873
Summary of Company's Nonvested Stock Option Activities	The following table summarizes information about the Corporation’s nonvested stock option activity for 2015 , 2014 , and 2013 . Stock Options Shares Weighted Average Grant Date Fair Value Nonvested at December 31, 2012 4,036,595 $ 5.11 Granted 1,020,979 3.80 Vested (1,680,981 ) 5.10 Forfeited (266,070 ) 5.05 Nonvested at December 31, 2013 3,110,523 $ 4.69 Granted 1,389,452 3.00 Vested (1,522,152 ) 4.92 Forfeited (207,161 ) 4.38 Nonvested at December 31, 2014 2,770,662 $ 3.74 Granted 1,348,504 3.08 Vested (1,459,709 ) 4.19 Forfeited (220,559 ) 3.28 Nonvested at December 31, 2015 2,438,898 $ 3.15
Summary of Restricted Stock Awards Activity (Excluding Salary Shares)	The following table summarizes information about the Corporation’s restricted stock activity for 2015 , 2014 , and 2013 . Restricted Stock Shares Weighted Average Grant Date Fair Value Outstanding at December 31, 2012 932,425 $ 13.60 Granted 1,276,868 14.03 Vested (626,480 ) 13.68 Forfeited (71,048 ) 13.92 Outstanding at December 31, 2013 1,511,765 $ 13.92 Granted 1,177,168 17.35 Vested (538,877 ) 14.12 Forfeited (167,930 ) 15.26 Outstanding at December 31, 2014 1,982,126 $ 15.79 Granted 1,173,847 18.09 Vested (709,582 ) 15.62 Forfeited (196,363 ) 16.87 Outstanding at December 31, 2015 2,250,028 $ 17.03

Retirement Plans (Tables)

Retirement Plans (Tables)	12 Months Ended
	Dec. 31, 2015
Defined Benefit Pension Plans and Defined Benefit Postretirement Plans Disclosure [Abstract]
Change in Benefit Obligation	The funded status and amounts recognized in the 2015 and 2014 consolidated balance sheets, as measured on December 31, 2015 and 2014 , respectively, for the Pension and Postretirement Plans were as follows. Pension Plan Postretirement Plan Pension Plan Postretirement Plan 2015 2015 2014 2014 ($ in Thousands) Change in Fair Value of Plan Assets Fair value of plan assets at beginning of year $ 303,496 $ — $ 282,000 $ — Actual return on plan assets 495 — 15,255 — Employer contributions — 264 21,000 343 Gross benefits paid (14,392 ) (264 ) (14,759 ) (343 ) Fair value of plan assets at end of year* $ 289,599 $ — $ 303,496 $ — Change in Benefit Obligation Net benefit obligation at beginning of year $ 171,333 $ 3,578 $ 154,624 $ 3,288 Service cost 11,257 — 11,058 — Interest cost 6,617 141 7,132 150 Actuarial (gain) loss (3,032 ) (19 ) 13,278 483 Gross benefits paid (14,392 ) (264 ) (14,759 ) (343 ) Net benefit obligation at end of year* $ 171,783 $ 3,436 $ 171,333 $ 3,578 Funded (unfunded) status $ 117,816 $ (3,436 ) $ 132,163 $ (3,578 ) Noncurrent assets 117,816 — 132,163 — Current liabilities — (274 ) — (330 ) Noncurrent liabilities — (3,162 ) — (3,248 ) Asset (Liability) Recognized in the Consolidated Balance Sheets $ 117,816 $ (3,436 ) $ 132,163 $ (3,578 ) * The fair value of the plan assets represented 169% and 177% of the net benefit obligation of the pension plan at December 31, 2015 and 2014 , respectively.
AOCI Components	Amounts recognized in accumulated other comprehensive loss, net of tax, as of December 31, 2015 and 2014 follow. Pension Plan Postretirement Plan Pension Plan Postretirement Plan 2015 2015 2014 2014 ($ in Thousands) Prior service cost $ 122 $ — $ 153 $ — Net actuarial loss 32,879 73 23,124 84 Amount not yet recognized in net periodic benefit cost, but recognized in accumulated other comprehensive loss $ 33,001 $ 73 $ 23,277 $ 84
Changes in OCI	Other changes in plan assets and benefit obligations recognized in other comprehensive income (loss) (“OCI”), net of tax, in 2015 and 2014 were as follows. Pension Plan 2015 Postretirement Plan 2015 Pension Plan 2014 Postretirement Plan 2014 ($ in Thousands) Net gain (loss) $ (17,911 ) $ 19 $ (17,945 ) $ (483 ) Amortization of prior service cost 50 — 58 — Amortization of actuarial gain (loss) 2,256 — 1,384 (35 ) Income tax (expense) benefit 5,880 (7 ) 6,308 199 Total Recognized in OCI $ (9,725 ) $ 12 $ (10,195 ) $ (319 )
Net period benefit cost for the pension and postretirement plans	The components of net periodic benefit cost for the Pension and Postretirement Plans for 2015 , 2014 , and 2013 were as follows. Pension Plan 2015 Postretirement Plan 2015 Pension Plan 2014 Postretirement Plan 2014 Pension Plan 2013 Postretirement Plan 2013 ($ in Thousands) Service cost $ 11,257 $ — $ 11,058 $ — $ 12,078 $ — Interest cost 6,617 141 7,132 150 6,237 142 Expected return on plan assets (21,438 ) — (19,922 ) — (17,647 ) — Amortization of: Prior service cost 50 — 58 — 72 — Actuarial (gain) loss 2,256 — 1,384 (35 ) 4,344 — Total net pension cost $ (1,258 ) $ 141 $ (290 ) $ 115 $ 5,084 $ 142
Weighted Average Benefit Assumptions	Pension Plan 2015 Postretirement Plan 2015 Pension Plan 2014 Postretirement Plan 2014 Weighted average assumptions used to determine benefit obligations: Discount rate 4.30 % 4.30 % 4.00 % 4.00 % Rate of increase in compensation levels 4.00 NA 4.00 NA Weighted average assumptions used to determine net periodic benefit costs: Discount rate 4.00 % 4.00 % 4.80 % 4.80 % Rate of increase in compensation levels 4.00 NA 4.00 NA Expected long-term rate of return on plan assets 7.50 NA 7.50 NA
Plan Asset Allocation Percentages	The asset allocation for the Pension Plan as of the December 31, 2015 and 2014 measurement dates, respectively, by asset category were as follows. Asset Category 2015 2014 Equity securities 60 % 64 % Fixed income securities 40 % 35 % Other — % 1 % Total 100 % 100 %
Pension Plan Investments	Based on these inputs, the following table summarizes the fair value of the Pension Plan’s investments as of December 31, 2015 and 2014 . Fair Value Measurements Using December 31, 2015 Level 1 Level 2 Level 3 ($ in Thousands) Pension Plan Investments: Money market account $ 481 $ 481 $ — $ — Mutual funds 168,982 168,982 — — Common /collective trust funds 120,136 — 120,136 — Total Pension Plan Investments $ 289,599 $ 169,463 $ 120,136 $ — Fair Value Measurements Using December 31, 2014 Level 1 Level 2 Level 3 ($ in Thousands) Pension Plan Investments: Money market account $ 2,868 $ 2,868 $ — $ — Mutual funds 185,483 185,483 — — Common /collective trust funds 115,145 — 115,145 — Total Pension Plan Investments $ 303,496 $ 188,351 $ 115,145 $ —
Expected Benefit Payments	The projected benefit payments for the Pension and Postretirement Plans at December 31, 2015 , 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. Pension Plan Postretirement Plan ($ in Thousands) Estimated future benefit payments: 2016 $ 14,218 $ 274 2017 13,885 257 2018 12,825 263 2019 12,580 250 2020 12,767 247 2021-2025 66,722 1,189
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. 2015 2014 100 bp Increase 100 bp Decrease 100 bp Increase 100 bp Decrease ($ in Thousands) Effect on total of service and interest cost $ 15 $ (13 ) $ 13 $ (11 ) Effect on postretirement benefit obligation $ 357 $ (310 ) $ 316 $ (277 )

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2015
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, 2015 2014 2013 ($ in Thousands) Current: Federal $ 82,449 $ 74,646 $ 50,628 State 2,560 1,000 2,653 Total current 85,009 75,646 53,281 Deferred: Federal (10,606 ) (805 ) 16,409 State 7,084 10,695 9,511 Total deferred (3,522 ) 9,890 25,920 Total income tax expense $ 81,487 $ 85,536 $ 79,201
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. 2015 2014 ($ in Thousands) Deferred tax assets: Allowance for loan losses $ 106,258 $ 99,219 Allowance for other losses 10,906 11,609 Accrued liabilities 6,802 5,773 Deferred compensation 31,677 31,392 State net operating losses 14,154 22,640 Nonaccrual interest 1,901 2,383 Other 5,811 7,929 Total deferred tax assets 177,509 180,945 Deferred tax liabilities: FHLB stock dividends 2,165 6,367 Prepaid expenses 69,396 68,955 Goodwill 25,770 24,049 Mortgage banking activities 15,704 13,147 Deferred loan fee income 17,770 21,199 State deferred taxes 6,366 9,011 Lease financing 3,042 2,313 Bank premises and equipment 7,491 9,532 Other 9,062 5,501 Total deferred tax liabilities 156,766 160,074 Net deferred tax assets 20,743 20,871 Tax effect of unrealized (gain) loss related to available for sale securities 219 (10,902 ) Tax effect of unrealized loss related to pension and postretirement benefits 20,404 14,468 20,623 3,566 Net deferred tax assets including items with tax effect recorded directly to OCI $ 41,366 $ 24,437
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. 2015 2014 2013 Federal income tax rate at statutory rate 35.0 % 35.0 % 35.0 % Increases (decreases) resulting from: Tax-exempt interest and dividends (5.0 )% (4.6 )% (4.5 )% State income taxes (net of federal benefit) 2.3 % 2.8 % 2.9 % Bank owned life insurance (1.2 )% (1.7 )% (1.5 )% Federal tax credits (0.5 )% (1.4 )% (1.0 )% Tax reserve adjustments (0.6 )% 0.7 % (1.9 )% Other 0.2 % 0.2 % 0.6 % Effective income tax rate 30.2 % 31.0 % 29.6 %
Summary Unrecognized Tax Benefits	A reconciliation of the beginning and ending amount of unrecognized tax benefits was as follows. 2015 2014 ($ in Millions) Balance at beginning of year $ 9 $ 6 Additions (subtractions) for tax positions related to prior years (2 ) 1 Additions for tax positions related to current year 2 2 Balance at end of year $ 9 $ 9

Derivative and Hedging Activi42

Derivative and Hedging Activities (Tables)	12 Months Ended
	Dec. 31, 2015
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Balance sheet category and fair values of derivative instruments not designated as hedging instruments	The table below identifies the balance sheet category and fair values of the Corporation’s free standing derivative instruments, which are not designated as hedging instruments. Notional Amount Fair Value Balance Sheet Category Weighted Average ($ in Thousands) Receive Rate (1) Pay Rate (1) Maturity December 31, 2015 Interest rate-related instruments — customer and mirror $ 1,665,965 $ 29,391 Trading assets 1.56 % 1.56 % 41 months Interest rate-related instruments — customer and mirror 1,665,965 (30,886 ) Trading liabilities 1.56 % 1.56 % 41 months Interest rate lock commitments (mortgage) 271,530 958 Other assets — — — Forward commitments (mortgage) 231,798 403 Other assets — — — Foreign currency exchange forwards 72,976 1,532 Trading assets — — — Foreign currency exchange forwards 65,649 (1,398 ) Trading liabilities — — — Commodity contracts 44,380 1,269 Trading assets — — — Commodity contracts 44,256 (1,146 ) Trading liabilities — — — Purchased options (time deposit) 104,582 2,715 Other assets — — — Written options (time deposit) 104,582 (2,715 ) Other liabilities — — — December 31, 2014 Interest rate-related instruments — customer and mirror $ 1,636,480 $ 33,023 Trading assets 1.60 % 1.60 % 42 months Interest rate-related instruments — customer and mirror 1,636,480 (35,372 ) Trading liabilities 1.60 % 1.60 % 42 months Interest rate lock commitments (mortgage) 126,379 1,947 Other assets — — — Forward commitments (mortgage) 234,500 (2,435 ) Other liabilities — — — Foreign currency exchange forwards 60,742 2,140 Trading assets — — — Foreign currency exchange forwards 56,573 (1,957 ) Trading liabilities — — — Purchased options (time deposit) 110,347 6,054 Other assets — — — Written options (time deposit) 110,347 (6,054 ) Other liabilities — — — (1) Reflects the weighted average receive rate and pay rate for the interest rate swap derivative financial instruments only.
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. ($ in Thousands) Income Statement Category of Gain / (Loss) Recognized in Income Gain / (Loss) Recognized in Income Year ended December 31, 2015 Interest rate-related instruments — customer and mirror, net Capital market fees, net $ 854 Interest rate lock commitments (mortgage) Mortgage banking, net (989 ) Forward commitments (mortgage) Mortgage banking, net 2,838 Foreign currency exchange forwards Capital market fees, net (49 ) Commodity contracts Capital market fees, net 123 Year ended December 31, 2014 Interest rate-related instruments — customer and mirror, net Capital market fees, net $ 486 Interest rate lock commitments (mortgage) Mortgage banking, net 1,531 Forward commitments (mortgage) Mortgage banking, net (3,736 ) Foreign currency exchange forwards Capital market fees, net 90

Balance Sheet Offsetting (Table

Balance Sheet Offsetting (Tables)	12 Months Ended
	Dec. 31, 2015
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, 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 ) $ — December 31, 2014 Derivative assets: Interest rate-related instruments $ 558 $ — $ 558 $ (558 ) $ — $ — Derivative liabilities: Interest rate-related instruments $ 34,087 $ — $ 34,087 $ (558 ) $ (26,105 ) $ 7,424

Commitments, Off-Balance Shee44

Commitments, Off-Balance Sheet Arrangements, and Contingent Liabilities (Tables)	12 Months Ended
	Dec. 31, 2015
Commitments and Contingencies Disclosure [Abstract]
Summary of lending-related and other commitments	The following is a summary of lending-related commitments. 2015 2014 ($ in Thousands) Commitments to extend credit, excluding commitments to originate residential mortgage loans held for sale(1)(2) $ 7,402,518 $ 6,884,411 Commercial letters of credit(1) 9,945 9,179 Standby letters of credit(3) 296,508 353,292 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, 2015 or 2014 . 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 December 31, 2015 compared to $4 million at December 31, 2014 , as an estimate of the fair value of these financial instruments.
Summary of changes in the residential mortgage repurchase reserve	The following summarizes the changes in the mortgage repurchase reserve for the years ended as follows. 2015 2014 ($ in Thousands) Balance at beginning of year $ 3,258 $ 5,737 Repurchase provision expense 428 505 Adjustments to provision expense (2,450 ) (2,250 ) Charge offs, net (39 ) (734 ) Balance at end of year $ 1,197 $ 3,258

Parent Company Only Financial45

Parent Company Only Financial Information (Tables)	12 Months Ended
	Dec. 31, 2015
Condensed Financial Information of Parent Company Only Disclosure [Abstract]
Parent Company Balance Sheet	BALANCE SHEETS December 31, 2015 2014 ($ in Thousands) ASSETS Cash and due from banks $ 610,862 $ 523,103 Investment securities available for sale, at fair value 61,847 76,159 Investment in subsidiaries 3,211,685 3,166,080 Other assets 73,781 94,332 Total assets $ 3,958,175 $ 3,859,674 LIABILITIES AND STOCKHOLDERS’ EQUITY Commercial paper $ 67,978 $ 74,297 Senior notes, at par 680,000 680,000 Subordinated notes, at par 250,000 250,000 Long-term funding capitalized costs (875 ) (143 ) Total long-term funding 929,125 929,857 Accrued expenses and other liabilities 23,826 55,269 Total liabilities 1,020,929 1,059,423 Preferred equity 121,379 59,727 Common equity 2,815,867 2,740,524 Total stockholders’ equity 2,937,246 2,800,251 Total liabilities and stockholders’ equity $ 3,958,175 $ 3,859,674
Parent Company Income Statement	STATEMENTS OF INCOME For the Years Ended December 31, 2015 2014 2013 ($ in Thousands) INCOME Dividends from subsidiaries $ 205,000 $ 223,000 $ 262,000 Interest income on notes receivable — 1,264 1,988 Other income 8,441 9,682 7,742 Total income 213,441 233,946 271,730 EXPENSE Interest expense on short and long-term funding 39,576 24,847 27,167 Other expense 4,684 745 8,029 Total expense 44,260 25,592 35,196 Income before income tax benefit and equity in undistributed net income (loss) of subsidiaries 169,181 208,354 236,534 Income tax benefit (1,665 ) (5,801 ) (7,086 ) Income before equity in undistributed net income (loss) of subsidiaries 170,846 214,155 243,620 Equity in undistributed net income (loss) of subsidiaries 17,455 (23,646 ) (54,928 ) Net income 188,301 190,509 188,692 Preferred stock dividends 7,155 5,002 5,158 Net income available to common equity $ 181,146 $ 185,507 $ 183,534
Parent Company Statement of Cash Flows	STATEMENTS OF CASH FLOWS For the Years Ended December 31, 2015 2014 2013 ($ in Thousands) OPERATING ACTIVITIES Net income $ 188,301 $ 190,509 $ 188,692 Adjustments to reconcile net income to net cash provided by operating activities: (Increase) decrease in equity in undistributed net income of subsidiaries (17,455 ) 23,646 54,928 Gain on sales of investment securities, net — (214 ) (456 ) Gain on sales of assets and impairment write-downs, net (5,673 ) (5,609 ) (1,007 ) Net change in other assets and other liabilities (10,997 ) (14,022 ) (103,954 ) Net cash provided by operating activities 154,176 194,310 138,203 INVESTING ACTIVITIES Proceeds from sales of investment securities 13,962 88,844 55,445 Purchase of investment securities — — (23,101 ) Net decrease in notes receivable — 46,594 3,049 Purchase of other assets, net of disposals 11,964 10,930 2,407 Net cash provided by investing activities 25,926 146,368 37,800 FINANCING ACTIVITIES Net increase (decrease) in short-term funding (6,319 ) 8,813 14,239 Proceeds from issuance of long-term funding — 496,030 — Repayment of long-term funding — (155,000 ) (25,821 ) Proceeds from issuance of preferred stock 62,966 — — Proceeds from issuance of common stock for stock-based compensation plans 20,054 13,228 9,305 Purchase of preferred stock (1,335 ) (2,451 ) (1,626 ) Cash dividends (69,555 ) (63,712 ) (60,149 ) Purchase of common stock returned to authorized but unissued (93,000 ) (150,498 ) — Purchase of treasury stock (5,154 ) (112,312 ) (123,349 ) Net cash provided by (used in) financing activities (92,343 ) 34,098 (187,401 ) Net increase (decrease) in cash and cash equivalents 87,759 374,776 (11,398 ) Cash and cash equivalents at beginning of year 523,103 148,327 159,725 Cash and cash equivalents at end of year $ 610,862 $ 523,103 $ 148,327

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2015
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, 2015 and 2014 , 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 December 31, 2015 Fair Value Measurements Using Level 1 Level 2 Level 3 ($ in Thousands) Assets: Investment securities available for sale: U.S. Treasury securities $ 997 $ 997 $ — $ — Residential mortgage-related securities: FNMA / FHLMC 1,414,626 — 1,414,626 — GNMA 1,590,003 — 1,590,003 — Private-label 1,709 — 1,709 — GNMA commercial mortgage-related securities 1,955,310 — 1,955,310 — Other securities (debt and equity) 4,769 1,569 3,000 200 Total investment securities available for sale $ 4,967,414 $ 2,566 $ 4,964,648 $ 200 Derivatives (trading and other assets) $ 36,268 $ — $ 34,907 $ 1,361 Liabilities: Derivatives (trading and other liabilities) $ 36,145 $ — $ 36,145 $ — December 31, 2014 Fair Value Measurements Using Level 1 Level 2 Level 3 ($ in Thousands) Assets: Investment securities available for sale: U.S. Treasury securities $ 998 $ 998 $ — $ — Municipal securities 582,679 — 582,679 — Residential mortgage-related securities: FNMA / FHLMC 3,563,457 — 3,563,457 — GNMA 167,332 — 167,332 — Private-label 2,294 — 2,294 — GNMA commercial mortgage-related securities 1,073,893 — 1,073,893 — Other securities (debt and equity) 6,159 2,959 3,000 200 Total investment securities available for sale $ 5,396,812 $ 3,957 $ 5,392,655 $ 200 Derivatives (trading and other assets) $ 43,164 $ — $ 41,217 $ 1,947 Liabilities: Derivatives (trading and other liabilities) $ 45,818 $ — $ 43,383 $ 2,435
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, 2015 and 2014 , 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, 2013 $ 299 $ 1,717 Total net losses included in income: Mortgage derivative loss — (2,205 ) Sale of investment securities (99 ) — Balance December 31, 2014 $ 200 $ (488 ) Total net gains included in income: Mortgage derivative gain — 1,849 Balance December 31, 2015 $ 200 $ 1,361
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 as of December 31, 2015 and 2014 , 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 December 31, 2015 Fair Value Measurements Using Income Statement Category of Adjustment Recognized in Income Level 1 Level 2 Level 3 ($ in Thousands) Assets: Loans held for sale $ 124,915 $ — $ 124,915 $ — Mortgage banking, net $ (155 ) Impaired loans(1) 41,891 — — 41,891 Provision for credit losses (7,796 ) Mortgage servicing rights 70,686 — — 70,686 Mortgage banking, net 425 December 31, 2014 Fair Value Measurements Using Income Statement Category of Adjustment Recognized in Income Level 1 Level 2 Level 3 ($ in Thousands) Assets: Loans held for sale $ 156,423 $ — $ 156,423 $ — Mortgage banking, net $ — Impaired loans(1) 53,832 — — 53,832 Provision for credit losses (17,272 ) Mortgage servicing rights 66,342 — — 66,342 Mortgage banking, net (321 ) (1) Represents individually evaluated impaired loans, net of the related allowance for loan losses.
Estimated fair values of financial instruments	The estimated fair values of the Corporation’s financial instruments were as follows. December 31, 2015 Carrying Amount Fair Value Fair Value Measurements Using Level 1 Level 2 Level 3 ($ in Thousands) Financial assets: Cash and due from banks $ 374,921 $ 374,921 $ 374,921 $ — $ — Interest-bearing deposits in other financial institutions 79,764 79,764 79,764 — — Federal funds sold and securities purchased under agreements to resell 19,000 19,000 19,000 — — Investment securities held to maturity 1,168,230 1,184,442 — 1,184,442 — Investment securities available for sale 4,967,414 4,967,414 2,566 4,964,648 200 FHLB and Federal Reserve Bank stocks 147,240 147,240 — 147,240 — Loans held for sale 124,915 124,915 — 124,915 — Loans, net 18,440,079 18,389,832 — — 18,389,832 Bank owned life insurance 583,019 583,019 — 583,019 — Interest rate-related instruments 29,391 29,391 — 29,391 — Foreign currency exchange forwards 1,532 1,532 — 1,532 — Interest rate lock commitments to originate residential mortgage loans held for sale 958 958 — — 958 Forward commitments to sell residential mortgage loans 403 403 — — 403 Purchased options (time deposit) 2,715 2,715 — 2,715 — Commodity contracts 1,269 1,269 — 1,269 — Financial liabilities: Noninterest-bearing demand, savings, interest-bearing demand, and money market accounts $ 19,444,863 $ 19,444,863 $ — $ — $ 19,444,863 Brokered CDs and other time deposits 1,562,802 1,564,464 — 1,564,464 — Short-term funding 834,416 834,416 — 834,416 — Long-term funding 2,679,350 2,728,112 — 2,728,112 — Interest rate-related instruments 30,886 30,886 — 30,886 — Foreign currency exchange forwards 1,398 1,398 — 1,398 — Commodity contracts 1,146 1,146 — 1,146 — Standby letters of credit (1) 2,954 2,954 — 2,954 — Written options (time deposit) 2,715 2,715 — 2,715 — December 31, 2014 Carrying Amount Fair Value Fair Value Measurements Using Level 1 Level 2 Level 3 ($ in Thousands) Financial assets: Cash and due from banks $ 444,113 $ 444,113 $ 444,113 $ — $ — Interest-bearing deposits in other financial institutions 571,924 571,924 571,924 — — Federal funds sold and securities purchased under agreements to resell 16,030 16,030 16,030 — — Investment securities held to maturity 404,455 413,067 — 413,067 — Investment securities available for sale 5,396,812 5,396,812 3,957 5,392,655 200 FHLB and Federal Reserve Bank stocks 189,107 189,107 — 189,107 — Loans held for sale 154,935 156,423 — 156,423 — Loans, net 17,327,544 17,427,647 — — 17,427,647 Bank owned life insurance 574,154 574,154 — 574,154 — Interest rate-related instruments 33,023 33,023 — 33,023 — Foreign currency exchange forwards 2,140 2,140 — 2,140 — Interest rate lock commitments to originate residential mortgage loans held for sale 1,947 1,947 — — 1,947 Purchased options (time deposit) 6,054 6,054 — 6,054 — Financial liabilities: Noninterest-bearing demand, savings, interest-bearing demand, and money market accounts $ 17,192,049 $ 17,192,049 $ — $ — $ 17,192,049 Brokered CDs and other time deposits 1,571,455 1,571,455 — 1,571,455 — Short-term funding 1,068,288 1,068,288 — 1,068,288 — Long-term funding 3,930,117 3,975,605 — 3,975,605 — Interest rate-related instruments 35,372 35,372 — 35,372 — Foreign currency exchange forwards 1,957 1,957 — 1,957 — Standby letters of credit(1) 3,542 3,542 — 3,542 — Forward commitments to sell residential mortgage loans 2,435 2,435 — 2,435 Written options (time deposit) 6,054 6,054 — 6,054 — (1) The commitment on standby letters of credit was $297 million and $353 million at December 31, 2015 and 2014 , respectively. See Note 16 for additional information on the standby letters of credit and for information on the fair value of lending-related commitments.

Regulatory Matters (Tables)

Regulatory Matters (Tables)	12 Months Ended
	Dec. 31, 2015
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) ($ in Thousands) Amount Ratio(1) Amount Ratio(1) Amount Ratio(1) 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 10.12 797,199 ≥ 4.00 % 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 11.50 794,035 ≥ 4.00 % 1,191,053 ≥ 6.00 % 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 % As of December 31, 2014 Associated Banc-Corp Total capital $ 2,350,898 12.66 % $ 1,485,412 ≥ 8.00 % Tier 1 capital 1,868,059 10.06 742,706 ≥ 4.00 % Common equity Tier 1 capital N/A N/A N/A ≥ N/A Leverage 1,868,059 7.48 998,967 ≥ 4.00 % Associated Bank, N.A. Total capital $ 2,449,514 13.26 % $ 1,477,785 ≥ 8.00 % $ 1,847,231 ≥ 10.00 % Tier 1 capital 2,217,861 12.01 738,892 ≥ 4.00 % 1,108,339 ≥ 6.00 % Common equity Tier 1 capital N/A N/A N/A ≥ N/A N/A ≥ N/A Leverage 2,217,861 8.92 994,103 ≥ 4.00 1,242,628 ≥ 5.00 % 1) Total capital ratio is defined as Tier 1 capital plus Tier 2 capital divided by total risk-weighted assets. The Tier 1 Capital ratio is defined as Tier 1 capital divided by total risk-weighted assets. Common equity Tier 1 is defined as Tier 1 capital excluding qualifying perpetual preferred stock and qualifying trust preferred securities divided by total risk weighted assets. The leverage ratio is defined as Tier 1 capital divided by the most recent quarter’s average total assets. 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, 2015
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, 2015 2014 2013 (In thousands, except per share data) Net income $ 188,301 $ 190,509 $ 188,692 Preferred stock dividends (7,155 ) (5,002 ) (5,158 ) Net income available to common equity $ 181,146 $ 185,507 $ 183,534 Common shareholder dividends (61,774 ) (58,123 ) (54,505 ) Unvested share-based payment awards (626 ) (587 ) (486 ) Undistributed earnings $ 118,746 $ 126,797 $ 128,543 Undistributed earnings allocated to common shareholders 117,498 125,646 127,592 Undistributed earnings allocated to unvested share-based payment awards 1,248 1,151 951 Undistributed earnings $ 118,746 $ 126,797 $ 128,543 Basic Distributed earnings to common shareholders $ 61,774 $ 58,123 $ 54,505 Undistributed earnings allocated to common shareholders 117,498 125,646 127,592 Total common shareholders earnings, basic $ 179,272 $ 183,769 $ 182,097 Diluted Distributed earnings to common shareholders $ 61,774 $ 58,123 $ 54,505 Undistributed earnings allocated to common shareholders 117,498 125,646 127,592 Total common shareholders earnings, diluted $ 179,272 $ 183,769 $ 182,097 Weighted average common shares outstanding 149,350 157,286 165,584 Effect of dilutive common stock awards 1,253 968 218 Diluted weighted average common shares outstanding 150,603 158,254 165,802 Basic earnings per common share $ 1.20 $ 1.17 $ 1.10 Diluted earnings per common share $ 1.19 $ 1.16 $ 1.10

Segment Reporting (Tables)

Segment Reporting (Tables)	12 Months Ended
	Dec. 31, 2015
Segment Reporting [Abstract]
Selected segment information	Information about the Corporation’s segments is presented below. Segment Income Statement Data ($ in Thousands) Corporate and Commercial Specialty Community, Consumer, and Business Risk Management and Shared Services Consolidated Total 2015 Net interest income $ 310,072 $ 349,134 $ 17,072 $ 676,278 Noninterest income 46,742 265,638 16,029 328,409 Total revenue 356,814 614,772 33,101 1,004,687 Credit provision* 41,913 25,614 (30,027 ) 37,500 Noninterest expense 141,912 492,419 63,068 697,399 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 49,213 221,379 19,727 290,319 Total revenue 345,930 531,823 93,533 971,286 Credit provision* 46,857 23,934 (54,791 ) 16,000 Noninterest expense 148,476 463,184 67,581 679,241 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 % 2013 Net interest income $ 321,346 $ 317,898 $ 6,299 $ 645,543 Noninterest income 48,417 247,667 17,015 313,099 Total revenue 369,763 565,565 23,314 958,642 Credit provision* 55,297 20,122 (65,319 ) 10,100 Noninterest expense 140,744 477,318 62,587 680,649 Income before income taxes 173,722 68,125 26,046 267,893 Income tax expense (benefit) 60,802 23,843 (5,444 ) 79,201 Net income $ 112,920 $ 44,282 $ 31,490 $ 188,692 Return on average allocated capital (ROCET1)** 12.5 % 7.8 % 6.5 % 9.8 % Segment Balance Sheet Data ($ in Thousands) Corporate and Commercial Specialty Community, Consumer, and Business Risk Management and Shared Services Consolidated Total 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 2013 Average earning assets $ 8,443,203 $ 7,225,943 $ 5,310,982 $ 20,980,128 Average loans 8,433,389 7,225,943 3,813 15,663,145 Average deposits 5,479,567 9,675,302 2,283,326 17,438,195 Average allocated capital (CET1)** $ 900,306 $ 570,634 $ 407,431 $ 1,878,371 * The consolidated credit provision is equal to the actual reported provision for credit losses. ** The Federal Reserve establishes capital adequacy requirements for the Corporation, including Tier 1 capital. Tier 1 capital is comprised of common capital and certain redeemable, non-cumulative preferred stock. Average allocated capital represents average common equity Tier 1 which is defined as average Tier 1 capital excluding qualifying perpetual preferred stock and qualifying trust preferred securities. This is a non-GAAP financial measure. For segment reporting purposes, the ROCET1 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, 2015
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, 2015 , 2014 , and 2013 , changes during the years then ended, and reclassifications out of accumulated other comprehensive income (loss) during the years ended December 31, 2015 , 2014 , and 2013 , respectively. Investments Securities Available For Sale Defined Benefit Pension and Post Retirement Obligations Accumulated Other Comprehensive Income (Loss) Balance December 31, 2012 $ 86,109 $ (37,506 ) $ 48,603 Other comprehensive income (loss) before reclassifications (158,207 ) 35,804 (122,403 ) Amounts reclassified from accumulated other comprehensive income (loss): Investment securities gain, net (564 ) — (564 ) Personnel expense — 4,416 4,416 Income tax (expense) benefit 61,266 (15,562 ) 45,704 Net other comprehensive income (loss) during period (97,505 ) 24,658 (72,847 ) 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 )

Summary of Significant Accoun51

Summary of Significant Accounting Policies (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Accounting Policies [Abstract]
Balance prior to reclassification, consumer, home equity		$ 1,600,000
Balance prior to reclassification, consumer, mortgage		4,472,800
Residential mortgage	$ 5,783,267	5,056,891
Home equity	1,005,802	1,051,927
Market valuation adjustment	155	0
Other real estate owned	$ 15,000	$ 17,000
Core Deposit Intangibles [Member]
Finite-Lived Intangible Assets [Line Items]
Weighted average lives of finite-lived intangible assets	10 years
Other Intangible Assets [Member]
Finite-Lived Intangible Assets [Line Items]
Weighted average lives of finite-lived intangible assets	12 years	14 years

Acquisition (Details)

Acquisition (Details) - USD ($) $ in Thousands	Feb. 17, 2015	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Business Acquisition [Line Items]
Common stock issued in acquisition		$ 43,530	$ 0	$ 0
Ahmann and Martin Company [Member]
Business Acquisition [Line Items]
Common stock issued in acquisition	$ 48,000
Maximum contingent consideration	$ 8,000
Goodwill acquired during period		40,000
Other Intangible Assets [Member]
Business Acquisition [Line Items]
Additions to finite-lived intangible assets		$ 12,115	$ 0	$ 0

Investment Securities, AFS and

Investment Securities, AFS and HTM Securities Amortized Costs and Fair Values (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Investment securities available for sale:
Amortized Cost	$ 4,984,867	$ 5,368,259
Gross Unrealized Gains	35,684	85,085
Gross Unrealized Losses	(53,137)	(56,532)
Fair Value	4,967,414	5,396,812
Investment securities held to maturity:
Amortized Cost	1,168,230	404,455
Gross Unrealized Gains	17,505	9,444
Gross Unrealized Losses	(1,293)	(832)
Fair Value	1,184,442	413,067
US Treasury Securities [Member]
Investment securities available for sale:
Amortized Cost	999	999
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(2)	(1)
Fair Value	997	998
Obligations of state and political subdivisions (municipal securities) [Member]
Investment securities available for sale:
Amortized Cost		560,839
Gross Unrealized Gains		21,869
Gross Unrealized Losses		(29)
Fair Value		582,679
Investment securities held to maturity:
Amortized Cost	1,043,767	404,455
Gross Unrealized Gains	16,803	9,444
Gross Unrealized Losses	(339)	(832)
Fair Value	1,060,231	413,067
Private Label [Member]
Investment securities available for sale:
Amortized Cost	1,722	2,297
Gross Unrealized Gains	1	7
Gross Unrealized Losses	(14)	(10)
Fair Value	1,709	2,294
Investment securities held to maturity:
Amortized Cost	0
Fair Value	0
GNMA Commercial Mortgage-Related Securities [Member]
Investment securities available for sale:
Amortized Cost	1,982,477	1,097,913
Gross Unrealized Gains	1,334	1,922
Gross Unrealized Losses	(28,501)	(25,942)
Fair Value	1,955,310	1,073,893
Investment securities held to maturity:
Amortized Cost	0
Fair Value	0
Other Debt And Other Equity Securities [Member]
Investment securities available for sale:
Amortized Cost	4,718	6,108
Gross Unrealized Gains	51	51
Gross Unrealized Losses	0	0
Fair Value	4,769	6,159
FNMA and FHLMC [Member] | Residential Related Securities [Member]
Investment securities available for sale:
Amortized Cost	1,388,995	3,534,240
Gross Unrealized Gains	33,791	59,640
Gross Unrealized Losses	(8,160)	(30,423)
Fair Value	1,414,626	3,563,457
Investment securities held to maturity:
Amortized Cost	41,469
Gross Unrealized Gains	513
Gross Unrealized Losses	(645)
Fair Value	41,337
GNMA [Member] | Residential Related Securities [Member]
Investment securities available for sale:
Amortized Cost	1,605,956	165,863
Gross Unrealized Gains	507	1,596
Gross Unrealized Losses	(16,460)	(127)
Fair Value	1,590,003	$ 167,332
Investment securities held to maturity:
Amortized Cost	82,994
Gross Unrealized Gains	189
Gross Unrealized Losses	(309)
Fair Value	$ 82,874

Investment Securities, AFS an54

Investment Securities, AFS and HTM Contractual Maturities (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Amortized Cost
Due in one year or less	$ 1,500
Due after one year through five years	4,199
Due after five years through ten years	0
Due after ten years	0
Total debt securities	5,699
Fair Value
Due in one year or less	1,515
Due after one year through five years	4,197
Due after five years through ten years	0
Due after ten years	0
Total debt securities	5,712
Investment securities available for sale, amortized cost	4,984,867	$ 5,368,259
Investment securities available for sale, at fair value	$ 4,967,414	5,396,812
Ratio of Fair Value to Amortized Cost	99.60%
Amortized Cost
Due in one year or less	$ 42,841
Due after one year through five years	244,257
Due after five years through ten years	253,429
Due after ten years	503,240
Held-to-maturity Debt Securities, Amortized Cost Basis	1,043,767
Amortized Cost	1,168,230	404,455
Fair Value
Due in one year or less	26,761
Due after one year through five years	255,899
Due after five years through ten years	261,934
Due after ten years	515,637
Held-to-maturity Securities, Debt Securities	1,060,231
Total debt securities	$ 1,184,442	413,067
Ratio of Fair Value to Amortized Cost	101.40%
Private Label [Member]
Fair Value
Investment securities available for sale, amortized cost	$ 1,722	2,297
Investment securities available for sale, at fair value	1,709	2,294
Amortized Cost
Amortized Cost	0
Fair Value
Total debt securities	0
GNMA Commercial Mortgage-Related Securities [Member]
Fair Value
Investment securities available for sale, amortized cost	1,982,477	1,097,913
Investment securities available for sale, at fair value	1,955,310	1,073,893
Amortized Cost
Amortized Cost	0
Fair Value
Total debt securities	0
Equity Securities [Member]
Fair Value
Investment securities available for sale, amortized cost	18
Investment securities available for sale, at fair value	54
Amortized Cost
Amortized Cost	0
Fair Value
Total debt securities	0
FNMA and FHLMC [Member] | Residential Related Securities [Member]
Fair Value
Investment securities available for sale, amortized cost	1,388,995	3,534,240
Investment securities available for sale, at fair value	1,414,626	3,563,457
Amortized Cost
Amortized Cost	41,469
Fair Value
Total debt securities	41,337
GNMA [Member] | Residential Related Securities [Member]
Fair Value
Investment securities available for sale, amortized cost	1,605,956	165,863
Investment securities available for sale, at fair value	1,590,003	$ 167,332
Amortized Cost
Amortized Cost	82,994
Fair Value
Total debt securities	$ 82,874

Investment Securities, Gains, L

Investment Securities, Gains, Losses, and Proceeds (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Available-for-sale Securities, Gross Realized Gain (Loss) [Abstract]
Gross gains	$ 12,270	$ 1,184	$ 637
Gross losses	(4,137)	(690)	(73)
Total investment securities gains, net	8,133	494	564
Sales of available for sale securities	$ 1,601,947	$ 102,011	$ 136,152

Investment Securities, AFS an56

Investment Securities, AFS and HTM Securities Gross Unrealized Losses (Details) $ in Thousands	Dec. 31, 2015USD ($)security	Dec. 31, 2014USD ($)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	$ (27,621)	$ (3,189)
Unrealized losses on available for sale securities, 12 months or more	(25,516)	(53,343)
Total unrealized losses on available for sale securities	(53,137)	(56,532)
Fair value of unrealized losses on available for sale securities, less than 12 months	2,789,260	669,839
Fair value of unrealized losses on available for sale securities, 12 months or more	787,969	1,719,118
Total fair value of unrealized losses on available for sale securities	$ 3,577,229	$ 2,388,957
Number of available for sale securities in a continuous unrealized loss position less than twelve months	105	33
Number of available for sale securities in a continuous unrealized loss position for twelve months or more	38	84
Held-to-maturity Securities Continuous Unrealized Loss Position [Abstract]
Unrealized losses on held to maturity securities, less than 12 months	$ (524)	$ (216)
Unrealized losses on held to maturity securities, 12 months or more	(769)	(616)
Total unrealized losses on held to maturity securities	(1,293)	(832)
Fair value of unrealized losses on held to maturity securities, less than 12 months	$ 81,390	$ 31,924
Held-to-maturity, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions, 12 Months or Longer	30	85
Fair value of unrealized losses on held to maturity securities, 12 months or more	$ 27,157	$ 38,915
Total fair value of unrealized losses on held to maturity securities	$ 108,547	$ 70,839
Held-to-maturity, Securities In Unrealized Loss Positions Qualitative Disclosure Number Of Positions, less than 12 Months	84	74
US Treasury Securities [Member]
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)	$ (1)
Unrealized losses on available for sale securities, 12 months or more	0	0
Total unrealized losses on available for sale securities	(2)	(1)
Fair value of unrealized losses on available for sale securities, less than 12 months	997	998
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	$ 997	$ 998
Number of available for sale securities in a continuous unrealized loss position less than twelve months	1	1
Number of available for sale securities in a continuous unrealized loss position for twelve months or more	0	0
Obligations of state and political subdivisions (municipal securities) [Member]
Unrealized losses and fair value of available for sale securities , by investment category and time length
Unrealized losses on available for sale securities, less than 12 months		$ (9)
Unrealized losses on available for sale securities, 12 months or more		(20)
Total unrealized losses on available for sale securities		(29)
Fair value of unrealized losses on available for sale securities, less than 12 months		3,374
Fair value of unrealized losses on available for sale securities, 12 months or more		2,133
Total fair value of unrealized losses on available for sale securities		$ 5,507
Number of available for sale securities in a continuous unrealized loss position less than twelve months		6
Number of available for sale securities in a continuous unrealized loss position for twelve months or more		6
Held-to-maturity Securities Continuous Unrealized Loss Position [Abstract]
Unrealized losses on held to maturity securities, less than 12 months	$ (146)	$ (216)
Unrealized losses on held to maturity securities, 12 months or more	(193)	(616)
Total unrealized losses on held to maturity securities	(339)	(832)
Fair value of unrealized losses on held to maturity securities, less than 12 months	23,137	31,924
Fair value of unrealized losses on held to maturity securities, 12 months or more	9,254	38,915
Total fair value of unrealized losses on held to maturity securities	$ 32,391	$ 70,839
Obligations of state and political subdivisions (municipal securities) [Member] | 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	53	74
Obligations of state and political subdivisions (municipal securities) [Member] | 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	24	85
Private Label [Member]
Unrealized losses and fair value of available for sale securities , by investment category and time length
Unrealized losses on available for sale securities, less than 12 months	$ (1)	$ (9)
Unrealized losses on available for sale securities, 12 months or more	(13)	(1)
Total unrealized losses on available for sale securities	(14)	(10)
Fair value of unrealized losses on available for sale securities, less than 12 months	83	1,772
Fair value of unrealized losses on available for sale securities, 12 months or more	1,565	27
Total fair value of unrealized losses on available for sale securities	$ 1,648	$ 1,799
Number of available for sale securities in a continuous unrealized loss position less than twelve months	1	1
Number of available for sale securities in a continuous unrealized loss position for twelve months or more	3	2
GNMA Commercial Mortgage-Related Securities [Member]
Unrealized losses and fair value of available for sale securities , by investment category and time length
Unrealized losses on available for sale securities, less than 12 months	$ (9,610)	$ (1,766)
Unrealized losses on available for sale securities, 12 months or more	(18,891)	(24,176)
Total unrealized losses on available for sale securities	(28,501)	(25,942)
Fair value of unrealized losses on available for sale securities, less than 12 months	1,132,844	329,982
Fair value of unrealized losses on available for sale securities, 12 months or more	448,218	460,425
Total fair value of unrealized losses on available for sale securities	$ 1,581,062	$ 790,407
Number of available for sale securities in a continuous unrealized loss position less than twelve months	40	9
Number of available for sale securities in a continuous unrealized loss position for twelve months or more	21	20
FNMA and FHLMC [Member] | Residential Related Securities [Member]
Unrealized losses and fair value of available for sale securities , by investment category and time length
Unrealized losses on available for sale securities, less than 12 months	$ (1,548)	$ (1,395)
Unrealized losses on available for sale securities, 12 months or more	(6,612)	(29,028)
Total unrealized losses on available for sale securities	(8,160)	(30,423)
Fair value of unrealized losses on available for sale securities, less than 12 months	220,852	330,839
Fair value of unrealized losses on available for sale securities, 12 months or more	338,186	1,246,093
Total fair value of unrealized losses on available for sale securities	$ 559,038	$ 1,576,932
Number of available for sale securities in a continuous unrealized loss position less than twelve months | security	17	15
Number of available for sale securities in a continuous unrealized loss position for twelve months or more | security	14	52
Held-to-maturity Securities Continuous Unrealized Loss Position [Abstract]
Unrealized losses on held to maturity securities, less than 12 months	$ (177)
Unrealized losses on held to maturity securities, 12 months or more	(468)
Total unrealized losses on held to maturity securities	(645)
Fair value of unrealized losses on held to maturity securities, less than 12 months	12,754
Fair value of unrealized losses on held to maturity securities, 12 months or more	11,106
Total fair value of unrealized losses on held to maturity securities	$ 23,860
FNMA and FHLMC [Member] | Residential Related Securities [Member] | 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	10
FNMA and FHLMC [Member] | Residential Related Securities [Member] | 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	3
GNMA [Member] | Residential Related Securities [Member]
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	$ (16,460)	$ (9)
Unrealized losses on available for sale securities, 12 months or more	0	(118)
Total unrealized losses on available for sale securities	(16,460)	(127)
Fair value of unrealized losses on available for sale securities, less than 12 months	1,434,484	2,874
Fair value of unrealized losses on available for sale securities, 12 months or more	0	10,440
Total fair value of unrealized losses on available for sale securities	$ 1,434,484	$ 13,314
Number of available for sale securities in a continuous unrealized loss position less than twelve months | security	46	1
Number of available for sale securities in a continuous unrealized loss position for twelve months or more | security	0	4
Held-to-maturity Securities Continuous Unrealized Loss Position [Abstract]
Unrealized losses on held to maturity securities, less than 12 months	$ (201)
Unrealized losses on held to maturity securities, 12 months or more	(108)
Total unrealized losses on held to maturity securities	(309)
Fair value of unrealized losses on held to maturity securities, less than 12 months	45,499
Fair value of unrealized losses on held to maturity securities, 12 months or more	6,797
Total fair value of unrealized losses on held to maturity securities	$ 52,296
GNMA [Member] | Residential Related Securities [Member] | 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	21
GNMA [Member] | Residential Related Securities [Member] | 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	3

Investment Securities (Details

Investment Securities (Details Textual) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Schedule of Available-for-sale Securities [Line Items]
Sales of available for sale securities	$ 1,601,947	$ 102,011	$ 136,152
Investment Securities (Textuals) [Abstract]
Securities pledged as collateral	3,200,000	2,800,000
Federal Home Loan Bank Stock	74,000	118,000
Federal Reserve Bank Stock	73,000	71,000
Reclassification, municipal securities	400,000
Reclassification, mortgage-related securities	125,000
Marketable Securities, Gain (Loss)	$ 8,133	$ 494	$ 564

Loans, Loan Composition (Detail

Loans, Loan Composition (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Loan composition
Commercial and industrial	$ 6,147,440	$ 5,905,902
Commercial real estate — owner occupied	918,212	1,007,937
Lease financing	43,243	51,529
Commercial and business lending	7,108,895	6,965,368
Commercial real estate — investor	3,234,266	3,056,485
Real estate construction	1,162,145	1,008,956
Commercial real estate lending	4,396,411	4,065,441
Total commercial	11,505,306	11,030,809
Home equity	1,005,802	1,051,927
Installment and credit cards	419,968	454,219
Residential mortgage	5,783,267	5,056,891
Total consumer	7,209,037	6,563,037
Total loans	$ 18,714,343	$ 17,593,846

Loans, Related Party Loan Rollf

Loans, Related Party Loan Rollforward (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2015USD ($)
Loans and Leases Receivable, Related Parties [Roll Forward]
Balance at beginning of year	$ 74,420
New loans	14,840
Repayments	(19,990)
Changes due to status of executive officers and directors	(32,673)
Balance at end of year	$ 36,597

Loans, Changes in the Allowance

Loans, Changes in the Allowance for Loan Losses (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Changes in the allowance for loan losses
Balance at beginning of year	$ 266,302	$ 268,315	$ 297,409
Provision for loan losses	38,000	13,000	10,000
Charge offs	(52,280)	(44,096)	(88,061)
Recoveries	22,242	29,083	48,967
Net charge offs	(30,038)	(15,013)	(39,094)
Balance at end of year	274,264	266,302	268,315
Change in the allowance for unfunded commitments
Allowance for Credit Losses	298,664	291,202	290,215
Reserve for Off-balance Sheet Activities [Member]
Change in the allowance for unfunded commitments
Balance at beginning of year	24,900	21,900	21,800
Provision for unfunded commitments	(500)	3,000	100
Balance at end of year	$ 24,400	$ 24,900	$ 21,900

Loans, Changes in the Allowan61

Loans, Changes in the Allowance for Loan Losses by Portfolio Segment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Changes in the allowance for loan losses by portfolio segment
Balance at beginning of year	$ 266,302	$ 268,315	$ 297,409
Provision for loan losses	38,000	13,000	10,000
Charge offs	(52,280)	(44,096)	(88,061)
Recoveries	22,242	29,083	48,967
Balance at end of year	274,264	266,302	268,315
Allowance for loan losses:
Ending balance impaired loans individually evaluated for impairment	7,963	17,866
Ending balance impaired loans collectively evaluated for impairment	25,706	32,565
Total Impaired Loans, Related Allowance	33,669	50,431
Ending balance all other loans collectively evaluated for impairment	240,595	215,871
Loans [Abstract]
Ending balance impaired loans individually evaluated for impairment	111,487	101,822
Ending balance impaired loans collectively evaluated for impairment	154,134	173,807
Total Impaired Loans, Recorded Investment	265,621	275,629
Ending balance all other loans collectively evaluated for impairment	18,448,722	17,318,217
Total loans	18,714,343	17,593,846
Commercial and Industrial Portfolio Segment [Member]
Changes in the allowance for loan losses by portfolio segment
Balance at beginning of year	116,025	104,501
Provision for loan losses	30,861	14,767
Charge offs	(27,687)	(14,633)
Recoveries	9,795	11,390
Balance at end of year	128,994	116,025	104,501
Allowance for loan losses:
Ending balance impaired loans individually evaluated for impairment	7,522	13,615
Ending balance impaired loans collectively evaluated for impairment	640	2,852
Total Impaired Loans, Related Allowance	8,162	16,467
Ending balance all other loans collectively evaluated for impairment	120,832	99,558
Loans [Abstract]
Ending balance impaired loans individually evaluated for impairment	89,935	45,118
Ending balance impaired loans collectively evaluated for impairment	31,299	38,437
Total Impaired Loans, Recorded Investment	121,234	83,555
Ending balance all other loans collectively evaluated for impairment	6,026,206	5,822,347
Total loans	6,147,440	5,905,902
Commercial Real Estate Owner Occupied Portfolio [Member]
Changes in the allowance for loan losses by portfolio segment
Balance at beginning of year	16,510	19,476
Provision for loan losses	3,894	(1,296)
Charge offs	(2,645)	(3,476)
Recoveries	921	1,806
Balance at end of year	18,680	16,510	19,476
Allowance for loan losses:
Ending balance impaired loans individually evaluated for impairment	0	1,490
Ending balance impaired loans collectively evaluated for impairment	448	1,731
Total Impaired Loans, Related Allowance	448	3,221
Ending balance all other loans collectively evaluated for impairment	18,232	13,289
Loans [Abstract]
Ending balance impaired loans individually evaluated for impairment	6,221	20,731
Ending balance impaired loans collectively evaluated for impairment	9,705	15,548
Total Impaired Loans, Recorded Investment	15,926	36,279
Ending balance all other loans collectively evaluated for impairment	902,286	971,658
Total loans	918,212	1,007,937
Finance Leases Portfolio Segment [Member]
Changes in the allowance for loan losses by portfolio segment
Balance at beginning of year	1,610	1,607
Provision for loan losses	(671)	35
Charge offs	0	(39)
Recoveries	26	7
Balance at end of year	965	1,610	1,607
Allowance for loan losses:
Ending balance impaired loans individually evaluated for impairment	0	574
Ending balance impaired loans collectively evaluated for impairment	0	0
Total Impaired Loans, Related Allowance	0	574
Ending balance all other loans collectively evaluated for impairment	965	1,036
Loans [Abstract]
Ending balance impaired loans individually evaluated for impairment	1,634	1,801
Ending balance impaired loans collectively evaluated for impairment	0	0
Total Impaired Loans, Recorded Investment	1,634	1,801
Ending balance all other loans collectively evaluated for impairment	41,609	49,728
Total loans	43,243	51,529
Commercial Real Estate Investor Portfolio Segment [Member]
Changes in the allowance for loan losses by portfolio segment
Balance at beginning of year	46,333	58,156
Provision for loan losses	(2,827)	(17,290)
Charge offs	(4,645)	(4,529)
Recoveries	4,157	9,996
Balance at end of year	43,018	46,333	58,156
Allowance for loan losses:
Ending balance impaired loans individually evaluated for impairment	229	1,649
Ending balance impaired loans collectively evaluated for impairment	1,602	1,938
Total Impaired Loans, Related Allowance	1,831	3,587
Ending balance all other loans collectively evaluated for impairment	41,187	42,746
Loans [Abstract]
Ending balance impaired loans individually evaluated for impairment	5,460	19,683
Ending balance impaired loans collectively evaluated for impairment	25,098	26,129
Total Impaired Loans, Recorded Investment	30,558	45,812
Ending balance all other loans collectively evaluated for impairment	3,203,708	3,010,673
Total loans	3,234,266	3,056,485
Real Estate Construction Portfolio Segment [Member]
Changes in the allowance for loan losses by portfolio segment
Balance at beginning of year	20,999	23,418
Provision for loan losses	2,749	(1,277)
Charge offs	(750)	(1,958)
Recoveries	2,268	816
Balance at end of year	25,266	20,999	23,418
Allowance for loan losses:
Ending balance impaired loans individually evaluated for impairment	0	328
Ending balance impaired loans collectively evaluated for impairment	453	767
Total Impaired Loans, Related Allowance	453	1,095
Ending balance all other loans collectively evaluated for impairment	24,813	19,904
Loans [Abstract]
Ending balance impaired loans individually evaluated for impairment	0	3,776
Ending balance impaired loans collectively evaluated for impairment	1,450	2,350
Total Impaired Loans, Recorded Investment	1,450	6,126
Ending balance all other loans collectively evaluated for impairment	1,160,695	1,002,830
Total loans	1,162,145	1,008,956
Home Equity Portfolio Segments [Member]
Changes in the allowance for loan losses by portfolio segment
Balance at beginning of year	26,464	27,932
Provision for loan losses	906	6,278
Charge offs	(7,048)	(10,946)
Recoveries	3,233	3,200
Balance at end of year	23,555	26,464	27,932
Allowance for loan losses:
Ending balance impaired loans individually evaluated for impairment	46	11
Ending balance impaired loans collectively evaluated for impairment	10,072	11,371
Total Impaired Loans, Related Allowance	10,118	11,382
Ending balance all other loans collectively evaluated for impairment	13,437	15,082
Loans [Abstract]
Ending balance impaired loans individually evaluated for impairment	1,281	962
Ending balance impaired loans collectively evaluated for impairment	21,032	23,698
Total Impaired Loans, Recorded Investment	22,313	24,660
Ending balance all other loans collectively evaluated for impairment	983,489	1,027,267
Total loans	1,005,802	1,051,927
Installment and Credit Cards Portfolio Segment [Member]
Changes in the allowance for loan losses by portfolio segment
Balance at beginning of year	6,435	2,416
Provision for loan losses	2,194	6,279
Charge offs	(3,869)	(2,876)
Recoveries	765	616
Balance at end of year	5,525	6,435	2,416
Allowance for loan losses:
Ending balance impaired loans individually evaluated for impairment	0	0
Ending balance impaired loans collectively evaluated for impairment	195	308
Total Impaired Loans, Related Allowance	195	308
Ending balance all other loans collectively evaluated for impairment	5,330	6,127
Loans [Abstract]
Ending balance impaired loans individually evaluated for impairment	0	0
Ending balance impaired loans collectively evaluated for impairment	1,154	1,587
Total Impaired Loans, Recorded Investment	1,154	1,587
Ending balance all other loans collectively evaluated for impairment	418,814	452,632
Total loans	419,968	454,219
Residential Portfolio Segment [Member]
Changes in the allowance for loan losses by portfolio segment
Balance at beginning of year	31,926	30,809
Provision for loan losses	894	5,504
Charge offs	(5,636)	(5,639)
Recoveries	1,077	1,252
Balance at end of year	28,261	31,926	$ 30,809
Allowance for loan losses:
Ending balance impaired loans individually evaluated for impairment	166	199
Ending balance impaired loans collectively evaluated for impairment	12,296	13,598
Total Impaired Loans, Related Allowance	12,462	13,797
Ending balance all other loans collectively evaluated for impairment	15,799	18,129
Loans [Abstract]
Ending balance impaired loans individually evaluated for impairment	6,956	9,751
Ending balance impaired loans collectively evaluated for impairment	64,396	66,058
Total Impaired Loans, Recorded Investment	71,352	75,809
Ending balance all other loans collectively evaluated for impairment	5,711,915	4,981,082
Total loans	$ 5,783,267	$ 5,056,891

Loans, Commercial Loans by Cred

Loans, Commercial Loans by Credit Quality Indicator (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Commercial loans by credit quality indicator
Commercial and industrial	$ 6,147,440	$ 5,905,902
Commercial real estate — owner occupied	918,212	1,007,937
Lease financing	43,243	51,529
Commercial and business lending	7,108,895	6,965,368
Commercial real estate — investor	3,234,266	3,056,485
Real estate construction	1,162,145	1,008,956
Commercial real estate lending	4,396,411	4,065,441
Total commercial	11,505,306	11,030,809
Pass [Member]
Commercial loans by credit quality indicator
Commercial and industrial	5,455,573	5,594,497
Commercial real estate — owner occupied	827,694	904,526
Lease financing	37,969	46,931
Commercial and business lending	6,321,236	6,545,954
Commercial real estate — investor	3,150,134	2,974,493
Real estate construction	1,156,524	998,972
Commercial real estate lending	4,306,658	3,973,465
Total commercial	10,627,894	10,519,419
Special Mention [Member]
Commercial loans by credit quality indicator
Commercial and industrial	339,953	119,328
Commercial real estate — owner occupied	38,886	18,437
Lease financing	1,190	88
Commercial and business lending	380,029	137,853
Commercial real estate — investor	27,630	12,137
Real estate construction	252	2,082
Commercial real estate lending	27,882	14,219
Total commercial	407,911	152,072
Potential Problem [Member]
Commercial loans by credit quality indicator
Commercial and industrial	230,680	108,522
Commercial real estate — owner occupied	35,706	48,695
Lease financing	2,450	2,709
Commercial and business lending	268,836	159,926
Commercial real estate — investor	25,944	24,043
Real estate construction	3,919	1,776
Commercial real estate lending	29,863	25,819
Total commercial	298,699	185,745
Impaired [Member]
Commercial loans by credit quality indicator
Commercial and industrial	121,234	83,555
Commercial real estate — owner occupied	15,926	36,279
Lease financing	1,634	1,801
Commercial and business lending	138,794	121,635
Commercial real estate — investor	30,558	45,812
Real estate construction	1,450	6,126
Commercial real estate lending	32,008	51,938
Total commercial	$ 170,802	$ 173,573

Loans, Consumer Loans by Credit

Loans, Consumer Loans by Credit Quality Indicator (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Loans and Leases Receivable, Gross, Consumer [Abstract]
Home equity	$ 1,005,802	$ 1,051,927
Installment and credit cards	419,968	454,219
Residential mortgage	5,783,267	5,056,891
Total consumer	7,209,037	6,563,037
Performing Financing Receivable [Member]
Loans and Leases Receivable, Gross, Consumer [Abstract]
Home equity	975,348	1,017,604
Installment and credit cards	416,944	450,698
Residential mortgage	5,704,189	4,972,455
Total consumer	7,096,481	6,440,757
Thirty To Eighty Nine Days Past Due [Member]
Loans and Leases Receivable, Gross, Consumer [Abstract]
Home equity	7,919	8,783
Installment and credit cards	1,870	1,932
Residential mortgage	4,930	4,846
Total consumer	14,719	15,561
Potential Problem [Member]
Loans and Leases Receivable, Gross, Consumer [Abstract]
Home equity	222	880
Installment and credit cards	0	2
Residential mortgage	2,796	3,781
Total consumer	3,018	4,663
Impaired [Member]
Loans and Leases Receivable, Gross, Consumer [Abstract]
Home equity	22,313	24,660
Installment and credit cards	1,154	1,587
Residential mortgage	71,352	75,809
Total consumer	$ 94,819	$ 102,056

Loans, Loans by Past Due Status

Loans, Loans by Past Due Status (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Summarized details of Loans
Total Past Due	$ 79,679	$ 127,000
Current	18,634,664	17,466,846
Total loans	18,714,343	17,593,846
Accruing loans past due 90 days or more	$ 2,000	$ 2,000
Percent of current nonaccrual loans	69.00%	54.00%
Financing Receivables, 30 to 59 Days Past Due [Member]
Summarized details of Loans
Total Past Due	$ 30,336	$ 39,373
Financing Receivables, 60 to 89 Days Past Due [Member]
Summarized details of Loans
Total Past Due	13,705	22,705
Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Summarized details of Loans
Total Past Due	35,638	64,922
Commercial And Industrial Financing Receivable [Member]
Summarized details of Loans
Total Past Due	7,019	26,654
Current	6,140,421	5,879,248
Total loans	6,147,440	5,905,902
Commercial And Industrial Financing Receivable [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Summarized details of Loans
Total Past Due	1,497	5,338
Commercial And Industrial Financing Receivable [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Summarized details of Loans
Total Past Due	425	10,908
Commercial And Industrial Financing Receivable [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Summarized details of Loans
Total Past Due	5,097	10,408
Commercial Real Estate Owner Occupied Portfolio [Member]
Summarized details of Loans
Total Past Due	11,015	22,462
Current	907,197	985,475
Total loans	918,212	1,007,937
Commercial Real Estate Owner Occupied Portfolio [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Summarized details of Loans
Total Past Due	7,142	11,626
Commercial Real Estate Owner Occupied Portfolio [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Summarized details of Loans
Total Past Due	2,572	2,240
Commercial Real Estate Owner Occupied Portfolio [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Summarized details of Loans
Total Past Due	1,301	8,596
Finance Leases Financing Receivable [Member]
Summarized details of Loans
Total Past Due	0	513
Current	43,243	51,016
Total loans	43,243	51,529
Finance Leases Financing Receivable [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Summarized details of Loans
Total Past Due	0	0
Finance Leases Financing Receivable [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Summarized details of Loans
Total Past Due	0	0
Finance Leases Financing Receivable [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Summarized details of Loans
Total Past Due	0	513
Commercial And Business Lending [Member]
Summarized details of Loans
Total Past Due	18,034	49,629
Current	7,090,861	6,915,739
Total loans	7,108,895	6,965,368
Commercial And Business Lending [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Summarized details of Loans
Total Past Due	8,639	16,964
Commercial And Business Lending [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Summarized details of Loans
Total Past Due	2,997	13,148
Commercial And Business Lending [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Summarized details of Loans
Total Past Due	6,398	19,517
Commercial Real Estate Investor Portfolio Segment [Member]
Summarized details of Loans
Total Past Due	8,103	16,289
Current	3,226,163	3,040,196
Total loans	3,234,266	3,056,485
Commercial Real Estate Investor Portfolio Segment [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Summarized details of Loans
Total Past Due	3,465	2,569
Commercial Real Estate Investor Portfolio Segment [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Summarized details of Loans
Total Past Due	1,158	955
Commercial Real Estate Investor Portfolio Segment [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Summarized details of Loans
Total Past Due	3,480	12,765
Commercial Real Estate Construction Financing Receivable [Member]
Summarized details of Loans
Total Past Due	917	1,942
Current	1,161,228	1,007,014
Total loans	1,162,145	1,008,956
Commercial Real Estate Construction Financing Receivable [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Summarized details of Loans
Total Past Due	403	1,038
Commercial Real Estate Construction Financing Receivable [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Summarized details of Loans
Total Past Due	87	106
Commercial Real Estate Construction Financing Receivable [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Summarized details of Loans
Total Past Due	427	798
Commercial Real Estate Lending [Member]
Summarized details of Loans
Total Past Due	9,020	18,231
Current	4,387,391	4,047,210
Total loans	4,396,411	4,065,441
Commercial Real Estate Lending [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Summarized details of Loans
Total Past Due	3,868	3,607
Commercial Real Estate Lending [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Summarized details of Loans
Total Past Due	1,245	1,061
Commercial Real Estate Lending [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Summarized details of Loans
Total Past Due	3,907	13,563
Commercial Financing Receivable [Member]
Summarized details of Loans
Total Past Due	27,054	67,860
Current	11,478,252	10,962,949
Total loans	11,505,306	11,030,809
Commercial Financing Receivable [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Summarized details of Loans
Total Past Due	12,507	20,571
Commercial Financing Receivable [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Summarized details of Loans
Total Past Due	4,242	14,209
Commercial Financing Receivable [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Summarized details of Loans
Total Past Due	10,305	33,080
Home Equity [Member]
Summarized details of Loans
Total Past Due	17,004	18,912
Current	988,798	1,033,015
Total loans	1,005,802	1,051,927
Home Equity [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Summarized details of Loans
Total Past Due	8,112	8,459
Home Equity [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Summarized details of Loans
Total Past Due	3,059	3,561
Home Equity [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Summarized details of Loans
Total Past Due	5,833	6,892
Installment and Credit Cards [Member]
Summarized details of Loans
Total Past Due	3,506	3,525
Current	416,462	450,694
Total loans	419,968	454,219
Installment and Credit Cards [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Summarized details of Loans
Total Past Due	1,242	1,282
Installment and Credit Cards [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Summarized details of Loans
Total Past Due	714	785
Installment and Credit Cards [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Summarized details of Loans
Total Past Due	1,550	1,458
Residential, Prime, Financing Receivable [Member]
Summarized details of Loans
Total Past Due	32,115	36,703
Current	5,751,152	5,020,188
Total loans	5,783,267	5,056,891
Residential, Prime, Financing Receivable [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Summarized details of Loans
Total Past Due	8,475	9,061
Residential, Prime, Financing Receivable [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Summarized details of Loans
Total Past Due	5,690	4,150
Residential, Prime, Financing Receivable [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Summarized details of Loans
Total Past Due	17,950	23,492
Consumer Loan [Member]
Summarized details of Loans
Total Past Due	52,625	59,140
Current	7,156,412	6,503,897
Total loans	7,209,037	6,563,037
Consumer Loan [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Summarized details of Loans
Total Past Due	17,829	18,802
Consumer Loan [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Summarized details of Loans
Total Past Due	9,463	8,496
Consumer Loan [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Summarized details of Loans
Total Past Due	25,333	31,842
Accruing Loans [Member]
Summarized details of Loans
Total Past Due	25,107	44,751
Current	18,510,978	17,371,682
Total loans	18,536,085	17,416,433
Accruing Loans [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Summarized details of Loans
Total Past Due	20,181	26,621
Accruing Loans [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Summarized details of Loans
Total Past Due	3,278	16,507
Accruing Loans [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Summarized details of Loans
Total Past Due	1,648	1,623
Accruing Loans [Member] | Commercial And Industrial Financing Receivable [Member]
Summarized details of Loans
Total Past Due	1,260	15,001
Current	6,054,239	5,841,238
Total loans	6,055,499	5,856,239
Accruing Loans [Member] | Commercial And Industrial Financing Receivable [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Summarized details of Loans
Total Past Due	602	4,466
Accruing Loans [Member] | Commercial And Industrial Financing Receivable [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Summarized details of Loans
Total Past Due	409	10,281
Accruing Loans [Member] | Commercial And Industrial Financing Receivable [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Summarized details of Loans
Total Past Due	249	254
Accruing Loans [Member] | Commercial Real Estate Owner Occupied Portfolio [Member]
Summarized details of Loans
Total Past Due	7,142	10,628
Current	903,021	971,484
Total loans	910,163	982,112
Accruing Loans [Member] | Commercial Real Estate Owner Occupied Portfolio [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Summarized details of Loans
Total Past Due	7,142	8,429
Accruing Loans [Member] | Commercial Real Estate Owner Occupied Portfolio [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Summarized details of Loans
Total Past Due	0	2,199
Accruing Loans [Member] | Commercial Real Estate Owner Occupied Portfolio [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Summarized details of Loans
Total Past Due	0	0
Accruing Loans [Member] | Finance Leases Financing Receivable [Member]
Summarized details of Loans
Total Past Due	0	0
Current	41,609	49,728
Total loans	41,609	49,728
Accruing Loans [Member] | Commercial And Business Lending [Member]
Summarized details of Loans
Total Past Due	8,402	25,629
Current	6,998,869	6,862,450
Total loans	7,007,271	6,888,079
Accruing Loans [Member] | Commercial And Business Lending [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Summarized details of Loans
Total Past Due	7,744	12,895
Accruing Loans [Member] | Commercial And Business Lending [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Summarized details of Loans
Total Past Due	409	12,480
Accruing Loans [Member] | Commercial And Business Lending [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Summarized details of Loans
Total Past Due	249	254
Accruing Loans [Member] | Commercial Real Estate Investor Portfolio Segment [Member]
Summarized details of Loans
Total Past Due	291	1,208
Current	3,225,332	3,032,592
Total loans	3,225,623	3,033,800
Accruing Loans [Member] | Commercial Real Estate Investor Portfolio Segment [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Summarized details of Loans
Total Past Due	291	712
Accruing Loans [Member] | Commercial Real Estate Investor Portfolio Segment [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Summarized details of Loans
Total Past Due	0	496
Accruing Loans [Member] | Commercial Real Estate Investor Portfolio Segment [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Summarized details of Loans
Total Past Due	0	0
Accruing Loans [Member] | Commercial Real Estate Construction Financing Receivable [Member]
Summarized details of Loans
Total Past Due	296	984
Current	1,160,909	1,002,573
Total loans	1,161,205	1,003,557
Accruing Loans [Member] | Commercial Real Estate Construction Financing Receivable [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Summarized details of Loans
Total Past Due	270	951
Accruing Loans [Member] | Commercial Real Estate Construction Financing Receivable [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Summarized details of Loans
Total Past Due	26	33
Accruing Loans [Member] | Commercial Real Estate Construction Financing Receivable [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Summarized details of Loans
Total Past Due	0	0
Accruing Loans [Member] | Commercial Real Estate Lending [Member]
Summarized details of Loans
Total Past Due	587	2,192
Current	4,386,241	4,035,165
Total loans	4,386,828	4,037,357
Accruing Loans [Member] | Commercial Real Estate Lending [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Summarized details of Loans
Total Past Due	561	1,663
Accruing Loans [Member] | Commercial Real Estate Lending [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Summarized details of Loans
Total Past Due	26	529
Accruing Loans [Member] | Commercial Real Estate Lending [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Summarized details of Loans
Total Past Due	0	0
Accruing Loans [Member] | Commercial Financing Receivable [Member]
Summarized details of Loans
Total Past Due	8,989	27,821
Current	11,385,110	10,897,615
Total loans	11,394,099	10,925,436
Accruing Loans [Member] | Commercial Financing Receivable [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Summarized details of Loans
Total Past Due	8,305	14,558
Accruing Loans [Member] | Commercial Financing Receivable [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Summarized details of Loans
Total Past Due	435	13,009
Accruing Loans [Member] | Commercial Financing Receivable [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Summarized details of Loans
Total Past Due	249	254
Accruing Loans [Member] | Home Equity [Member]
Summarized details of Loans
Total Past Due	7,919	8,835
Current	982,639	1,026,641
Total loans	990,558	1,035,476
Accruing Loans [Member] | Home Equity [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Summarized details of Loans
Total Past Due	6,190	6,988
Accruing Loans [Member] | Home Equity [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Summarized details of Loans
Total Past Due	1,729	1,795
Accruing Loans [Member] | Home Equity [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Summarized details of Loans
Total Past Due	0	52
Accruing Loans [Member] | Installment and Credit Cards [Member]
Summarized details of Loans
Total Past Due	3,269	3,249
Current	416,374	450,357
Total loans	419,643	453,606
Accruing Loans [Member] | Installment and Credit Cards [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Summarized details of Loans
Total Past Due	1,195	1,186
Accruing Loans [Member] | Installment and Credit Cards [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Summarized details of Loans
Total Past Due	675	746
Accruing Loans [Member] | Installment and Credit Cards [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Summarized details of Loans
Total Past Due	1,399	1,317
Accruing Loans [Member] | Residential, Prime, Financing Receivable [Member]
Summarized details of Loans
Total Past Due	4,930	4,846
Current	5,726,855	4,997,069
Total loans	5,731,785	5,001,915
Accruing Loans [Member] | Residential, Prime, Financing Receivable [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Summarized details of Loans
Total Past Due	4,491	3,889
Accruing Loans [Member] | Residential, Prime, Financing Receivable [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Summarized details of Loans
Total Past Due	439	957
Accruing Loans [Member] | Residential, Prime, Financing Receivable [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Summarized details of Loans
Total Past Due	0	0
Accruing Loans [Member] | Consumer Loan [Member]
Summarized details of Loans
Total Past Due	16,118	16,930
Current	7,125,868	6,474,067
Total loans	7,141,986	6,490,997
Accruing Loans [Member] | Consumer Loan [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Summarized details of Loans
Total Past Due	11,876	12,063
Accruing Loans [Member] | Consumer Loan [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Summarized details of Loans
Total Past Due	2,843	3,498
Accruing Loans [Member] | Consumer Loan [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Summarized details of Loans
Total Past Due	1,399	1,369
Nonaccrual Loan [Member]
Summarized details of Loans
Total Past Due	54,572	82,249
Current	123,686	95,164
Total loans	178,258	177,413
Nonaccrual Loan [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Summarized details of Loans
Total Past Due	10,155	12,752
Nonaccrual Loan [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Summarized details of Loans
Total Past Due	10,427	6,198
Nonaccrual Loan [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Summarized details of Loans
Total Past Due	33,990	63,299
Nonaccrual Loan [Member] | Commercial And Industrial Financing Receivable [Member]
Summarized details of Loans
Total Past Due	5,759	11,653
Current	86,182	38,010
Total loans	91,941	49,663
Nonaccrual Loan [Member] | Commercial And Industrial Financing Receivable [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Summarized details of Loans
Total Past Due	895	872
Nonaccrual Loan [Member] | Commercial And Industrial Financing Receivable [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Summarized details of Loans
Total Past Due	16	627
Nonaccrual Loan [Member] | Commercial And Industrial Financing Receivable [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Summarized details of Loans
Total Past Due	4,848	10,154
Nonaccrual Loan [Member] | Commercial Real Estate Owner Occupied Portfolio [Member]
Summarized details of Loans
Total Past Due	3,873	11,834
Current	4,176	13,991
Total loans	8,049	25,825
Nonaccrual Loan [Member] | Commercial Real Estate Owner Occupied Portfolio [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Summarized details of Loans
Total Past Due	0	3,197
Nonaccrual Loan [Member] | Commercial Real Estate Owner Occupied Portfolio [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Summarized details of Loans
Total Past Due	2,572	41
Nonaccrual Loan [Member] | Commercial Real Estate Owner Occupied Portfolio [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Summarized details of Loans
Total Past Due	1,301	8,596
Nonaccrual Loan [Member] | Finance Leases Financing Receivable [Member]
Summarized details of Loans
Total Past Due	0	513
Current	1,634	1,288
Total loans	1,634	1,801
Nonaccrual Loan [Member] | Finance Leases Financing Receivable [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Summarized details of Loans
Total Past Due	0	0
Nonaccrual Loan [Member] | Finance Leases Financing Receivable [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Summarized details of Loans
Total Past Due	0	0
Nonaccrual Loan [Member] | Finance Leases Financing Receivable [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Summarized details of Loans
Total Past Due	0	513
Nonaccrual Loan [Member] | Commercial And Business Lending [Member]
Summarized details of Loans
Total Past Due	9,632	24,000
Current	91,992	53,289
Total loans	101,624	77,289
Nonaccrual Loan [Member] | Commercial And Business Lending [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Summarized details of Loans
Total Past Due	895	4,069
Nonaccrual Loan [Member] | Commercial And Business Lending [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Summarized details of Loans
Total Past Due	2,588	668
Nonaccrual Loan [Member] | Commercial And Business Lending [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Summarized details of Loans
Total Past Due	6,149	19,263
Nonaccrual Loan [Member] | Commercial Real Estate Investor Portfolio Segment [Member]
Summarized details of Loans
Total Past Due	7,812	15,081
Current	831	7,604
Total loans	8,643	22,685
Nonaccrual Loan [Member] | Commercial Real Estate Investor Portfolio Segment [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Summarized details of Loans
Total Past Due	3,174	1,857
Nonaccrual Loan [Member] | Commercial Real Estate Investor Portfolio Segment [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Summarized details of Loans
Total Past Due	1,158	459
Nonaccrual Loan [Member] | Commercial Real Estate Investor Portfolio Segment [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Summarized details of Loans
Total Past Due	3,480	12,765
Nonaccrual Loan [Member] | Commercial Real Estate Construction Financing Receivable [Member]
Summarized details of Loans
Total Past Due	621	958
Current	319	4,441
Total loans	940	5,399
Nonaccrual Loan [Member] | Commercial Real Estate Construction Financing Receivable [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Summarized details of Loans
Total Past Due	133	87
Nonaccrual Loan [Member] | Commercial Real Estate Construction Financing Receivable [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Summarized details of Loans
Total Past Due	61	73
Nonaccrual Loan [Member] | Commercial Real Estate Construction Financing Receivable [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Summarized details of Loans
Total Past Due	427	798
Nonaccrual Loan [Member] | Commercial Real Estate Lending [Member]
Summarized details of Loans
Total Past Due	8,433	16,039
Current	1,150	12,045
Total loans	9,583	28,084
Nonaccrual Loan [Member] | Commercial Real Estate Lending [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Summarized details of Loans
Total Past Due	3,307	1,944
Nonaccrual Loan [Member] | Commercial Real Estate Lending [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Summarized details of Loans
Total Past Due	1,219	532
Nonaccrual Loan [Member] | Commercial Real Estate Lending [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Summarized details of Loans
Total Past Due	3,907	13,563
Nonaccrual Loan [Member] | Commercial Financing Receivable [Member]
Summarized details of Loans
Total Past Due	18,065	40,039
Current	93,142	65,334
Total loans	111,207	105,373
Nonaccrual Loan [Member] | Commercial Financing Receivable [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Summarized details of Loans
Total Past Due	4,202	6,013
Nonaccrual Loan [Member] | Commercial Financing Receivable [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Summarized details of Loans
Total Past Due	3,807	1,200
Nonaccrual Loan [Member] | Commercial Financing Receivable [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Summarized details of Loans
Total Past Due	10,056	32,826
Nonaccrual Loan [Member] | Home Equity [Member]
Summarized details of Loans
Total Past Due	9,085	10,077
Current	6,159	6,374
Total loans	15,244	16,451
Nonaccrual Loan [Member] | Home Equity [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Summarized details of Loans
Total Past Due	1,922	1,471
Nonaccrual Loan [Member] | Home Equity [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Summarized details of Loans
Total Past Due	1,330	1,766
Nonaccrual Loan [Member] | Home Equity [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Summarized details of Loans
Total Past Due	5,833	6,840
Nonaccrual Loan [Member] | Installment and Credit Cards [Member]
Summarized details of Loans
Total Past Due	237	276
Current	88	337
Total loans	325	613
Nonaccrual Loan [Member] | Installment and Credit Cards [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Summarized details of Loans
Total Past Due	47	96
Nonaccrual Loan [Member] | Installment and Credit Cards [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Summarized details of Loans
Total Past Due	39	39
Nonaccrual Loan [Member] | Installment and Credit Cards [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Summarized details of Loans
Total Past Due	151	141
Nonaccrual Loan [Member] | Residential, Prime, Financing Receivable [Member]
Summarized details of Loans
Total Past Due	27,185	31,857
Current	24,297	23,119
Total loans	51,482	54,976
Nonaccrual Loan [Member] | Residential, Prime, Financing Receivable [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Summarized details of Loans
Total Past Due	3,984	5,172
Nonaccrual Loan [Member] | Residential, Prime, Financing Receivable [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Summarized details of Loans
Total Past Due	5,251	3,193
Nonaccrual Loan [Member] | Residential, Prime, Financing Receivable [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Summarized details of Loans
Total Past Due	17,950	23,492
Nonaccrual Loan [Member] | Consumer Loan [Member]
Summarized details of Loans
Total Past Due	36,507	42,210
Current	30,544	29,830
Total loans	67,051	72,040
Nonaccrual Loan [Member] | Consumer Loan [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Summarized details of Loans
Total Past Due	5,953	6,739
Nonaccrual Loan [Member] | Consumer Loan [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Summarized details of Loans
Total Past Due	6,620	4,998
Nonaccrual Loan [Member] | Consumer Loan [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Summarized details of Loans
Total Past Due	$ 23,934	$ 30,473

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, 2015	Dec. 31, 2014
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	$ 265,621	$ 275,629
Unpaid Principal Balance	284,433	310,811
Related Allowance	33,669	50,431
Average Recorded Investment	273,011	290,370
Interest Income Recognized	8,716	9,384
Interest income recognized on accruing restructured loans	$ 4,000	$ 5,000
Net Recorded Investment of the Impaired Loans	82.00%	72.00%
Loans With Related Allowance [Member]
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	$ 186,275	$ 232,166
Unpaid Principal Balance	197,109	253,186
Related Allowance	33,669	50,431
Average Recorded Investment	178,871	242,219
Interest Income Recognized	6,798	8,797
Loans With No Related Allowance [Member]
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	79,346	43,463
Unpaid Principal Balance	87,324	57,625
Related Allowance	0	0
Average Recorded Investment	94,140	48,151
Interest Income Recognized	1,918	587
Commercial And Industrial Financing Receivable [Member]
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	121,234	83,555
Unpaid Principal Balance	130,034	93,048
Related Allowance	8,162	16,467
Average Recorded Investment	124,499	88,855
Interest Income Recognized	2,512	3,221
Commercial And Industrial Financing Receivable [Member] | Loans With Related Allowance [Member]
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	57,785	76,433
Unpaid Principal Balance	59,409	80,414
Related Allowance	8,162	16,467
Average Recorded Investment	46,833	80,004
Interest Income Recognized	855	3,139
Commercial And Industrial Financing Receivable [Member] | Loans With No Related Allowance [Member]
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	63,449	7,122
Unpaid Principal Balance	70,625	12,634
Related Allowance	0	0
Average Recorded Investment	77,666	8,851
Interest Income Recognized	1,657	82
Commercial Real Estate Owner Occupied Portfolio [Member]
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	15,926	36,279
Unpaid Principal Balance	16,452	40,826
Related Allowance	448	3,221
Average Recorded Investment	16,621	38,848
Interest Income Recognized	427	900
Commercial Real Estate Owner Occupied Portfolio [Member] | Loans With Related Allowance [Member]
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	9,705	19,839
Unpaid Principal Balance	9,804	21,807
Related Allowance	448	3,221
Average Recorded Investment	10,087	20,878
Interest Income Recognized	412	681
Commercial Real Estate Owner Occupied Portfolio [Member] | Loans With No Related Allowance [Member]
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	6,221	16,440
Unpaid Principal Balance	6,648	19,019
Related Allowance	0	0
Average Recorded Investment	6,534	17,970
Interest Income Recognized	15	219
Finance Leases Financing Receivable [Member]
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	1,634	1,801
Unpaid Principal Balance	1,634	1,801
Related Allowance	0	574
Average Recorded Investment	1,907	2,009
Interest Income Recognized	0	0
Finance Leases Financing Receivable [Member] | Loans With Related Allowance [Member]
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	0	1,801
Unpaid Principal Balance	0	1,801
Related Allowance	0	574
Average Recorded Investment	0	2,009
Interest Income Recognized	0	0
Finance Leases Financing Receivable [Member] | Loans With No Related Allowance [Member]
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	1,634
Unpaid Principal Balance	1,634
Related Allowance	0
Average Recorded Investment	1,907
Interest Income Recognized	0
Commercial And Business Lending [Member]
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	138,794	121,635
Unpaid Principal Balance	148,120	135,675
Related Allowance	8,610	20,262
Average Recorded Investment	143,027	129,712
Interest Income Recognized	2,939	4,121
Commercial And Business Lending [Member] | Loans With Related Allowance [Member]
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	67,490	98,073
Unpaid Principal Balance	69,213	104,022
Related Allowance	8,610	20,262
Average Recorded Investment	56,920	102,891
Interest Income Recognized	1,267	3,820
Commercial And Business Lending [Member] | Loans With No Related Allowance [Member]
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	71,304	23,562
Unpaid Principal Balance	78,907	31,653
Related Allowance	0	0
Average Recorded Investment	86,107	26,821
Interest Income Recognized	1,672	301
Commercial Real Estate Investor Portfolio Segment [Member]
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	30,558	45,812
Unpaid Principal Balance	32,284	54,905
Related Allowance	1,831	3,587
Average Recorded Investment	31,041	48,671
Interest Income Recognized	2,004	1,383
Commercial Real Estate Investor Portfolio Segment [Member] | Loans With Related Allowance [Member]
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	27,822	36,841
Unpaid Principal Balance	29,444	40,869
Related Allowance	1,831	3,587
Average Recorded Investment	28,278	38,657
Interest Income Recognized	1,914	1,250
Commercial Real Estate Investor Portfolio Segment [Member] | Loans With No Related Allowance [Member]
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	2,736	8,971
Unpaid Principal Balance	2,840	14,036
Related Allowance	0	0
Average Recorded Investment	2,763	10,014
Interest Income Recognized	90	133
Commercial Real Estate Construction Financing Receivable [Member]
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	1,450	6,126
Unpaid Principal Balance	2,154	9,725
Related Allowance	453	1,095
Average Recorded Investment	1,667	7,059
Interest Income Recognized	66	105
Commercial Real Estate Construction Financing Receivable [Member] | Loans With Related Allowance [Member]
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	1,450	3,043
Unpaid Principal Balance	2,154	5,910
Related Allowance	453	1,095
Average Recorded Investment	1,667	3,818
Interest Income Recognized	66	105
Commercial Real Estate Construction Financing Receivable [Member] | Loans With No Related Allowance [Member]
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	0	3,083
Unpaid Principal Balance	0	3,815
Related Allowance	0	0
Average Recorded Investment	0	3,241
Interest Income Recognized	0	0
Commercial Real Estate Lending [Member]
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	32,008	51,938
Unpaid Principal Balance	34,438	64,630
Related Allowance	2,284	4,682
Average Recorded Investment	32,708	55,730
Interest Income Recognized	2,070	1,488
Commercial Real Estate Lending [Member] | Loans With Related Allowance [Member]
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	29,272	39,884
Unpaid Principal Balance	31,598	46,779
Related Allowance	2,284	4,682
Average Recorded Investment	29,945	42,475
Interest Income Recognized	1,980	1,355
Commercial Real Estate Lending [Member] | Loans With No Related Allowance [Member]
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	2,736	12,054
Unpaid Principal Balance	2,840	17,851
Related Allowance	0	0
Average Recorded Investment	2,763	13,255
Interest Income Recognized	90	133
Commercial Financing Receivable [Member]
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	170,802	173,573
Unpaid Principal Balance	182,558	200,305
Related Allowance	10,894	24,944
Average Recorded Investment	175,735	185,442
Interest Income Recognized	5,009	5,609
Commercial Financing Receivable [Member] | Loans With Related Allowance [Member]
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	96,762	137,957
Unpaid Principal Balance	100,811	150,801
Related Allowance	10,894	24,944
Average Recorded Investment	86,865	145,366
Interest Income Recognized	3,247	5,175
Commercial Financing Receivable [Member] | Loans With No Related Allowance [Member]
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	74,040	35,616
Unpaid Principal Balance	81,747	49,504
Related Allowance	0	0
Average Recorded Investment	88,870	40,076
Interest Income Recognized	1,762	434
Home Equity [Member]
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	22,313	24,660
Unpaid Principal Balance	24,533	27,391
Related Allowance	10,118	11,382
Average Recorded Investment	23,168	25,938
Interest Income Recognized	1,177	1,275
Home Equity [Member] | Loans With Related Allowance [Member]
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	21,769	23,874
Unpaid Principal Balance	23,989	26,585
Related Allowance	10,118	11,382
Average Recorded Investment	22,624	25,087
Interest Income Recognized	1,147	1,257
Home Equity [Member] | Loans With No Related Allowance [Member]
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	544	786
Unpaid Principal Balance	544	806
Related Allowance	0	0
Average Recorded Investment	544	851
Interest Income Recognized	30	18
Installment and Credit Cards [Member]
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	1,154	1,587
Unpaid Principal Balance	1,225	1,795
Related Allowance	195	308
Average Recorded Investment	1,199	1,736
Interest Income Recognized	30	58
Installment and Credit Cards [Member] | Loans With Related Allowance [Member]
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	1,154	1,587
Unpaid Principal Balance	1,225	1,795
Related Allowance	195	308
Average Recorded Investment	1,199	1,736
Interest Income Recognized	30	58
Installment and Credit Cards [Member] | Loans With No Related Allowance [Member]
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
Residential, Prime, Financing Receivable [Member]
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	71,352	75,809
Unpaid Principal Balance	76,117	81,320
Related Allowance	12,462	13,797
Average Recorded Investment	72,909	77,254
Interest Income Recognized	2,500	2,442
Residential, Prime, Financing Receivable [Member] | Loans With Related Allowance [Member]
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	66,590	68,748
Unpaid Principal Balance	71,084	74,005
Related Allowance	12,462	13,797
Average Recorded Investment	68,183	70,030
Interest Income Recognized	2,374	2,307
Residential, Prime, Financing Receivable [Member] | Loans With No Related Allowance [Member]
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	4,762	7,061
Unpaid Principal Balance	5,033	7,315
Related Allowance	0	0
Average Recorded Investment	4,726	7,224
Interest Income Recognized	126	135
Consumer Loan [Member]
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	94,819	102,056
Unpaid Principal Balance	101,875	110,506
Related Allowance	22,775	25,487
Average Recorded Investment	97,276	104,928
Interest Income Recognized	3,707	3,775
Consumer Loan [Member] | Loans With Related Allowance [Member]
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	89,513	94,209
Unpaid Principal Balance	96,298	102,385
Related Allowance	22,775	25,487
Average Recorded Investment	92,006	96,853
Interest Income Recognized	3,551	3,622
Consumer Loan [Member] | Loans With No Related Allowance [Member]
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	5,306	7,847
Unpaid Principal Balance	5,577	8,121
Related Allowance	0	0
Average Recorded Investment	5,270	8,075
Interest Income Recognized	$ 156	$ 153

Loans, Troubled Debt Restructur

Loans, Troubled Debt Restructurings Performing and Nonaccrual (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Financing Receivable, Modifications [Line Items]
Performing Restructured Loans	$ 87,363	$ 98,216	$ 123,985
Nonaccrual Restructured Loans	37,684	57,656	59,585
Commercial and Industrial Portfolio Segment [Member]
Financing Receivable, Modifications [Line Items]
Performing Restructured Loans	29,293	33,892	32,517
Nonaccrual Restructured Loans	1,714	3,260	6,900
Commercial Real Estate Owner Occupied Portfolio [Member]
Financing Receivable, Modifications [Line Items]
Performing Restructured Loans	7,877	10,454	13,009
Nonaccrual Restructured Loans	2,703	5,656	10,999
Commercial Real Estate Investor Portfolio Segment [Member]
Financing Receivable, Modifications [Line Items]
Performing Restructured Loans	21,915	23,127	44,946
Nonaccrual Restructured Loans	3,936	15,216	18,069
Commercial Real Estate Construction Financing Receivable [Member]
Financing Receivable, Modifications [Line Items]
Performing Restructured Loans	510	727	3,793
Nonaccrual Restructured Loans	177	2,438	2,065
Home Equity Portfolio Segments [Member]
Financing Receivable, Modifications [Line Items]
Performing Restructured Loans	7,069	8,209	8,197
Nonaccrual Restructured Loans	4,522	4,838	4,441
Installment and Credit Cards [Member]
Financing Receivable, Modifications [Line Items]
Performing Restructured Loans	829	974	246
Nonaccrual Restructured Loans	40	199	451
Residential Portfolio Segment [Member]
Financing Receivable, Modifications [Line Items]
Performing Restructured Loans	19,870	20,833	21,277
Nonaccrual Restructured Loans	$ 24,592	$ 26,049	$ 16,660

Loans, Loans Modified in a Trou

Loans, Loans Modified in a Troubled Debt Restructuring (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2015USD ($)loan	Dec. 31, 2014USD ($)loan	Dec. 31, 2013USD ($)loan
Financing Receivable, Modifications [Line Items]
Number of Loans | loan	211	309	278
Recorded Investment	$ 41,131	$ 38,870	$ 64,052
Unpaid Principal Balance	$ 42,765	$ 40,660	$ 71,319
Commercial and Industrial Portfolio Segment [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans | loan	12	15	48
Recorded Investment	$ 2,219	$ 7,681	$ 11,833
Unpaid Principal Balance	$ 2,900	$ 7,711	$ 14,543
Commercial Real Estate Owner Occupied Portfolio [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans | loan	5	4	12
Recorded Investment	$ 3,694	$ 1,465	$ 8,823
Unpaid Principal Balance	$ 3,901	$ 1,625	$ 9,035
Commercial Real Estate Investor Portfolio Segment [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans | loan	5	6	25
Recorded Investment	$ 21,573	$ 6,097	$ 26,480
Unpaid Principal Balance	$ 21,640	$ 6,521	$ 28,516
Commercial Real Estate Construction Financing Receivable [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans | loan	4	2	9
Recorded Investment	$ 78	$ 15	$ 1,822
Unpaid Principal Balance	$ 79	$ 15	$ 1,961
Home Equity Portfolio Segments [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans | loan	88	117	82
Recorded Investment	$ 3,103	$ 3,913	$ 3,991
Unpaid Principal Balance	$ 3,249	$ 4,308	$ 4,242
Installment and Credit Cards [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans | loan	0	2	3
Recorded Investment	$ 0	$ 24	$ 193
Unpaid Principal Balance	$ 0	$ 26	$ 200
Residential Portfolio Segment [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans | loan	97	163	99
Recorded Investment	$ 10,464	$ 19,675	$ 10,910
Unpaid Principal Balance	$ 10,996	$ 20,454	$ 12,822

Loans, Troubled Debt Restruct68

Loans, Troubled Debt Restructurings Subsequent Default (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2015USD ($)loan	Dec. 31, 2014USD ($)loan	Dec. 31, 2013USD ($)loan
Financing Receivable, Modifications [Line Items]
Number of Loans | loan	91	155	64
Recorded Investment | $	$ 8,232	$ 19,065	$ 9,256
Commercial and Industrial Portfolio Segment [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans | loan	2	1	15
Recorded Investment | $	$ 197	$ 52	$ 1,493
Commercial Real Estate Owner Occupied Portfolio [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans | loan	0	3	4
Recorded Investment | $	$ 0	$ 785	$ 542
Commercial Real Estate Investor Portfolio Segment [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans | loan	0	13	4
Recorded Investment | $	$ 0	$ 6,200	$ 1,784
Commercial Real Estate Construction Financing Receivable [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans | loan	0	1	4
Recorded Investment | $	$ 0	$ 160	$ 80
Home Equity Portfolio Segments [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans | loan	28	54	11
Recorded Investment | $	$ 1,220	$ 1,802	$ 829
Installment and Credit Cards [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans | loan	0	3	0
Recorded Investment | $	$ 0	$ 34	$ 0
Residential Portfolio Segment [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans | loan	61	80	26
Recorded Investment | $	$ 6,815	$ 10,032	$ 4,528

Loans (Details Textuals)

Loans (Details Textuals) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Accounts, Notes, Loans and Financing Receivable [Line Items]
Home equity	$ 1,005,802	$ 1,051,927
Commitments to lend additional funds to borrowers with restructured loans	7,000
Balance prior to reclassification, consumer, home equity		1,600,000
Residential mortgage	5,783,267	5,056,891
Balance prior to reclassification, consumer, mortgage		4,472,800
Allowance for loan losses	274,264	266,302	$ 268,315	$ 297,409
Commercial Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses	128,994	116,025	$ 104,501
Oil and Gas Industry [Member] | Commercial Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses	$ 41,900	$ 17,000
Percentage of allowance allocated	5.58%	2.26%

Goodwill and Intangible Asset70

Goodwill and Intangible Assets (Details Textuals) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Business Acquisition [Line Items]
Goodwill	$ 968,844	$ 929,168
Ahmann and Martin Company [Member]
Business Acquisition [Line Items]
Goodwill acquired during period	40,000
Customer Relationships [Member]
Business Acquisition [Line Items]
Additions to finite-lived intangible assets	$ 12,000

Goodwill and Intangible Assets,

Goodwill and Intangible Assets, Summary of Core Deposit and Other Intangibles (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Summary of core deposit intangibles and other intangibles
Amortization of other intangible assets	$ 3,094	$ 3,747	$ 4,043
Core Deposit Intangibles [Member]
Summary of core deposit intangibles and other intangibles
Gross carrying amount	19,545	36,230	36,230
Accumulated amortization	(19,152)	(34,433)	(31,565)
Total Estimated Amortization Expense	393	1,797	4,665
Amortization of other intangible assets	1,404	2,868	3,122
Other Intangible Assets [Member]
Summary of core deposit intangibles and other intangibles
Gross carrying amount	31,398	19,283	19,283
Accumulated amortization	(15,333)	(13,643)	(12,764)
Total Estimated Amortization Expense	16,065	5,640	6,519
Additions during the period	12,115	0	0
Amortization of other intangible assets	$ 1,690	$ 879	$ 921

Goodwill and Intangible Asset72

Goodwill and Intangible Assets, Mortgage Servicing Rights Roll-Forward (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Mortgage servicing rights:
Mortgage servicing rights at beginning of year	$ 61,379	$ 64,193	$ 61,425
Additions	12,372	8,253	18,256
Amortization	(11,601)	(11,067)	(15,488)
Mortgage servicing rights at end of year	62,150	61,379	64,193
Valuation Allowance for Impairment of Recognized Servicing Assets [Roll Forward]
Valuation allowance at beginning of year	(1,234)	(913)	(15,476)
(Additions) recoveries, net	(425)	321	(14,563)
Valuation allowance at end of year	(809)	(1,234)	(913)
Mortgage servicing rights, net	61,341	60,145	63,280
Fair value of mortgage servicing rights	70,686	66,342	74,444
Portfolio of residential mortgage loans serviced for others (“servicing portfolio”)	$ 7,915,224	$ 7,999,294	$ 8,084,000
Mortgage servicing rights, net to servicing portfolio	0.77%	0.75%	0.78%
Mortgage servicing rights expense	$ 11,176	$ 11,388	$ 925

Goodwill and Intangible Asset73

Goodwill and Intangible Assets, Estimated Future Amortization Expense (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Core Deposit Intangibles [Member]
Estimated future amortization expense
Year ending December 31, 2016	$ 281
Year ending December 31, 2017	112
Year ending December 31, 2018	0
Year ending December 31, 2019	0
Year ending December 31, 2020	0
Beyond 2,020	0
Total Estimated Amortization Expense	393	$ 1,797	$ 4,665
Other Intangible Assets [Member]
Estimated future amortization expense
Year ending December 31, 2016	1,735
Year ending December 31, 2017	1,702
Year ending December 31, 2018	1,672
Year ending December 31, 2019	1,373
Year ending December 31, 2020	1,256
Beyond 2,020	8,327
Total Estimated Amortization Expense	16,065	$ 5,640	$ 6,519
Mortgage Service Rights [Member]
Estimated future amortization expense
Year ending December 31, 2016	10,109
Year ending December 31, 2017	8,415
Year ending December 31, 2018	7,010
Year ending December 31, 2019	5,894
Year ending December 31, 2020	4,978
Beyond 2,020	25,744
Total Estimated Amortization Expense	$ 62,150

Premises and Equipment, Summary

Premises and Equipment, Summary Composition (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Property, Plant and Equipment, Net, by Type [Abstract]
Cost	$ 553,830
Accumulated Depreciation	286,224
Net Book Value	267,606	$ 274,688
Land [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Cost	52,104
Accumulated Depreciation	0
Net Book Value	52,104	52,790
Land Improvements [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Cost	11,570
Accumulated Depreciation	4,909
Net Book Value	$ 6,661	6,608
Land Improvements [Member] | Maximum [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Estimated Useful Lives	15 years
Land Improvements [Member] | Minimum [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Estimated Useful Lives	3 years
Buildings [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Cost	$ 261,418
Accumulated Depreciation	119,986
Net Book Value	$ 141,432	139,702
Buildings [Member] | Maximum [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Estimated Useful Lives	39 years
Buildings [Member] | Minimum [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Estimated Useful Lives	5 years
Computers [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Cost	$ 37,875
Accumulated Depreciation	31,503
Net Book Value	$ 6,372	7,518
Computers [Member] | Maximum [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Estimated Useful Lives	5 years
Computers [Member] | Minimum [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Estimated Useful Lives	3 years
Furniture, fixtures and other equipment [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Cost	$ 159,094
Accumulated Depreciation	109,300
Net Book Value	$ 49,794	55,747
Furniture, fixtures and other equipment [Member] | Maximum [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Estimated Useful Lives	15 years
Furniture, fixtures and other equipment [Member] | Minimum [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Estimated Useful Lives	3 years
Leasehold Improvements [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Cost	$ 31,769
Accumulated Depreciation	20,526
Net Book Value	$ 11,243	$ 12,323
Leasehold Improvements [Member] | Maximum [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Estimated Useful Lives	15 years
Leasehold Improvements [Member] | Minimum [Member]
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, 2015USD ($)
Operating Leases, Future Minimum Payments Receivable [Abstract]
2,016	$ 10,417
2,017	9,957
2,018	8,678
2,019	8,348
2,020	7,583
Thereafter	17,968
Total	$ 62,951

Premises and Equipment (Details

Premises and Equipment (Details Textuals) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Property, Plant and Equipment [Abstract]
Depreciation and amortization	$ 33	$ 34	$ 33
Rental expense under leases	$ 13	$ 11	$ 13

Deposits, Composition (Details)

Deposits, Composition (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Deposits, by Type [Abstract]
Noninterest-bearing demand deposits	$ 5,562,466	$ 4,505,272
Savings deposits	1,334,420	1,235,277
Interest-bearing demand deposits	3,445,000	3,126,854
Money market deposits	9,102,977	8,324,646
Brokered certificates of deposit	42,443	42,556
Other time deposits	1,520,359	1,528,899
Total deposits	$ 21,007,665	$ 18,763,504

Deposits (Details Textuals)

Deposits (Details Textuals) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Deposits [Abstract]
Time Deposits, $100,000 or More	$ 466	$ 457
Time Deposits, $250,000 Or More	$ 127	$ 152

Deposits, Time Deposit Maturiti

Deposits, Time Deposit Maturities (Details) $ in Thousands	Dec. 31, 2015USD ($)
Time Deposits, Fiscal Year Maturity [Abstract]
2,016	$ 885,249
2,017	161,528
2,018	238,184
2,019	151,161
2,020	123,022
Thereafter	3,658
Total	$ 1,562,802

Short-term Funding, Composition

Short-term Funding, Composition (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Short-term Debt [Abstract]
Federal funds purchased	$ 47,870	$ 109,770
Securities sold under agreements to repurchase	383,568	384,221
Federal funds purchased and securities sold under agreements to repurchase	431,438	493,991
FHLB advances	335,000	500,000
Commercial paper	67,978	74,297
Other short-term funding	402,978	574,297
Total short-term funding	$ 834,416	$ 1,068,288

Short-term Funding Short-term F

Short-term Funding Short-term Funding, Repurchase Agreements (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase agreements	$ 383,568
Gross amounts of recognized liabilities for repurchase agreements	383,568	$ 384,221
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase agreements	383,568
Maturity Overnight and on Demand [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase agreements	383,568
Maturity Overnight and on Demand [Member] | Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase agreements	383,568
Maturity Less than 30 Days [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase agreements	0
Maturity Less than 30 Days [Member] | Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase agreements	0
Maturity 30 to 90 Days [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase agreements	0
Maturity 30 to 90 Days [Member] | Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase agreements	0
Maturity Greater than 90 Days [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase agreements	0
Maturity Greater than 90 Days [Member] | Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase agreements	$ 0

Short-term Funding Short-term82

Short-term Funding Short-term Funding (Details Textuals) (Details) $ in Millions	Dec. 31, 2015USD ($)
Short-term Debt [Abstract]
Collateral for repurchase agreements	$ 474

Long-term Funding, Composition

Long-term Funding, Composition (Details) - USD ($) $ in Thousands	1 Months Ended
	Nov. 30, 2014	Dec. 31, 2015	Dec. 31, 2014	Sep. 30, 2011	Mar. 31, 2011
Long-term Funding
FHLB advances		$ 1,750,225	$ 3,000,260
Senior notes, at par		680,000	680,000
Subordinated notes, at par		250,000	250,000
Other Long-term Debt and Capitalized Costs		(875)	(143)
Total long-term funding		$ 2,679,350	$ 3,930,117
Long Term Debt Disclosure [Line Items]
Percentage of interest rate on senior notes	2.75%
Long-term Funding (Textuals) [Abstract]
Weighted average interest rate of Long-term advances		0.24%	0.11%
Long-term FHLB Advances		$ 5,500,000
New senior debt issued	$ 250,000			$ 130,000	$ 300,000
Subordinated debentures issued	$ 250,000
Fixed coupon interest rate of subordinated debt	4.25%
Total Federal Home Loan Bank Advances		$ 2,100,000
Senior Notes [Member]
Long Term Debt Disclosure [Line Items]
Percentage of interest rate on senior notes					5.125%

Long-term Funding, Maturities (

Long-term Funding, Maturities (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Maturities of Long-term Debt [Abstract]
2,016	$ 430,317
2,017	27
2,018	1,500,000
2,019	499,617
2,020	172
Thereafter	249,217
Total long-term funding	$ 2,679,350	$ 3,930,117

Stockholders' Equity (Details T

Stockholders' Equity (Details Textuals) - USD ($)	Jun. 15, 2015	Sep. 14, 2011	Nov. 30, 2008	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Aug. 28, 2015	Jul. 23, 2013	Dec. 06, 2011
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
Value authorized but issued					$ 8,500,000
Purchase of preferred stock				$ 1,335,000	$ 2,451,000	$ 1,626,000
Series B Preferred Stock [Member]
Class of Stock [Line Items]
Stock repurchase program authorized amount								$ 10,000,000
Treasury stock shares acquired (in shares)				50,000	88,000
Remaining authorized repurchase amount				$ 5,000,000
Preferred Stock, Dividend Rate, Percentage		8.00%
Depositary shares issued (in shares)		2,600,000
Purchase of preferred stock				1,335,000	$ 2,451,000
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 [Member]
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)	2,600,000
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
Common Stock [Member]
Class of Stock [Line Items]
Treasury stock shares acquired (in shares)				5,000,000	14,300,000
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				$ 93,000,000	$ 259,000,000
Treasury stock acquired average cost per share (in usd per share)				$ 18.73	$ 18.12
Repurchased amount for minimum tax withholding settlement				$ 5,000,000	$ 4,000,000
Repurchased shares for minimum tax withholding settlements (in shares)				285,000	225,000
Minimum tax withholding settlement average cost per share (in usd per share)				$ 17.87	$ 16.50
Remaining authorized repurchase amount				$ 108,000,000

Stock-Based Compensation, Stock

Stock-Based Compensation, Stock Option Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Fair value assumptions of stock options
Dividend yield	2.00%	2.00%	2.00%
Risk-free interest rate	2.00%	2.00%	0.99%
Weighted average expected volatility	20.00%	20.00%	34.35%
Weighted average expected life	6 years	6 years	6 years
Weighted average per share fair value of stock options (in usd per share)	$ 3.08	$ 3	$ 3.80
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Stock Options Shares Outstanding, Beginning balance (in shares)	7,847,338	8,034,243	8,640,558
Granted (in shares)	1,348,504	1,389,452	1,020,979
Exercised (in shares)	(1,351,646)	(933,143)	(642,202)
Forfeited or expired (in shares)	(1,215,053)	(643,214)	(985,092)
Stock Options Shares Outstanding, Ending balance (in shares)	6,629,143	7,847,338	8,034,243
Options exercisable (in shares)	4,190,245	5,076,676	4,923,720
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)	$ 18.34	$ 18.37	$ 18.88
Granted, Weighted Average Exercise Price (in usd per share)	17.95	17.45	14.02
Exercised, Weighted Average Exercise Price (in usd per share)	13.90	13.77	13.43
Forfeited or expired, Weighted Average Exercise Price (in usd per share)	29.13	23.50	21.49
Stock Options Outstanding, Weighted Average Exercise Price, Ending balance (in usd per share)	17.22	18.34	18.37
Options Exercisable, Weighted Average Exercise Price (in usd per share)	$ 17.25	$ 19.96	$ 21.48
Stock Options Outstanding, Weighted Average Remaining Contractual Term	6 years 2 months 26 days	5 years 9 months 15 days	6 years 11 days
Options exercisable, Weighted Average Remaining Contractual Term	4 years 11 months 5 days	4 years 4 months 28 days	4 years 7 months 13 days
Stock Options Outstanding, Aggregate Intrinsic Value	$ 18,730	$ 23,986	$ 20,838
Options exercisable, Aggregate Intrinsic Value	$ 14,873	$ 14,953	$ 8,580

Stock-Based Compensation, Nonve

Stock-Based Compensation, Nonvested Stock Option Activity (Details) - $ / shares	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Summary of nonvested stock activity
Granted (in shares)	1,348,504	1,389,452	1,020,979
Nonvested Stock Options [Member]
Summary of nonvested stock activity
Stock Options Shares Outstanding, Beginning balance (in shares)	2,770,662	3,110,523	4,036,595
Granted (in shares)	1,348,504	1,389,452	1,020,979
Vested (in shares)	(1,459,709)	(1,522,152)	(1,680,981)
Forfeited (in shares)	(220,559)	(207,161)	(266,070)
Stock Options Shares Outstanding, Ending balance (in shares)	2,438,898	2,770,662	3,110,523
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)	$ 3.74	$ 4.69	$ 5.11
Granted Weighted Average Grant Date Fair Value (in usd per share)	3.08	3	3.80
Vested Weighted Average Grant Date Fair Value (in usd per share)	4.19	4.92	5.10
Forfeited Weighted Average Grant Date Fair Value (in usd per share)	3.28	4.38	5.05
Nonvested Weighted Average Grant Date Fair Value, Ending balance (in usd per share)	$ 3.15	$ 3.74	$ 4.69

Stock-Based Compensation, Restr

Stock-Based Compensation, Restricted Stock Activity (Details) - $ / shares	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
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)	1,982,126	1,511,765	932,425
Granted (in shares)	1,173,847	1,177,168	1,276,868
Vested (in shares)	(709,582)	(538,877)	(626,480)
Forfeited (in shares)	(196,363)	(167,930)	(71,048)
Outstanding Shares, Ending balance (in shares)	2,250,028	1,982,126	1,511,765
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)	$ 15.79	$ 13.92	$ 13.60
Granted, Weighted Average Grant Date Fair Value (in usd per share)	18.09	17.35	14.03
Vested, Weighted Average Grant Date Fair Value (in usd per share)	15.62	14.12	13.68
Forfeited, Weighted Average Grant Date Fair Value (in usd per share)	16.87	15.26	13.92
Outstanding Weighted Average Grant Date Fair Value, Ending balance (in usd per share)	$ 17.03	$ 15.79	$ 13.92

Stock-Based Compensation (Detai

Stock-Based Compensation (Details Textuals) - USD ($) $ in Thousands, shares in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
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	7,000	$ 4,000	$ 2,000
Total fair value of vested stock options	6,000	7,000	9,000
Employee Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Recognized compensation expense for accelerated vesting of stock options	710
Recognized compensation expense for vesting of stock options	$ 4,000	6,000	8,000
Total compensation cost not yet recognized, period for recognition	fourth quarter 2018
Restricted Stock Award [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Recognized compensation expense for accelerated vesting of stock options	$ 2,000
Recognized compensation expense for vesting of stock options	15,000	$ 10,000	$ 7,000
Unvested share-based payment awards	$ 23,000
Total compensation cost not yet recognized, period for recognition	fourth quarter 2018
2013 Incentive Compensation Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares remaining available for grant (in shares)	11
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
Vesting period	4 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	3 years
Vesting period	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	4 years
Vesting period	3 years
Executive Officer [Member] | Restricted Stock Award [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	4 years	3 years
Non-executive Employees [Member] | Restricted Stock Award [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	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, 2015	Dec. 31, 2014	Dec. 31, 2013
Change in Fair Value of Plan Assets
Fair value of plan assets at beginning of year	$ 303,496
Fair value of plan assets at end of year	289,599	$ 303,496
Pension Plan [Member]
Change in Fair Value of Plan Assets
Fair value of plan assets at beginning of year	303,496	282,000
Actual return on plan assets	495	15,255
Employer contributions	0	21,000
Gross benefits paid	(14,392)	(14,759)
Fair value of plan assets at end of year	289,599	303,496	$ 282,000
Change in Benefit Obligation
Net benefit obligation at beginning of year	171,333	154,624
Service cost	11,257	11,058	12,078
Interest cost	6,617	7,132	6,237
Actuarial (gain) loss	(3,032)	13,278
Gross benefits paid	(14,392)	(14,759)
Net benefit obligation at end of year	171,783	171,333	154,624
Funded (unfunded) status	117,816	132,163
Noncurrent assets	117,816	132,163
Current liabilities	0	0
Noncurrent liabilities	0	0
Asset (Liability) Recognized in the Consolidated Balance Sheets	117,816	132,163
Other Postretirement Benefit Plan [Member]
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	264	343
Gross benefits paid	(264)	(343)
Fair value of plan assets at end of year	0	0	0
Change in Benefit Obligation
Net benefit obligation at beginning of year	3,578	3,288
Service cost	0	0	0
Interest cost	141	150	142
Actuarial (gain) loss	(19)	483
Gross benefits paid	(264)	(343)
Net benefit obligation at end of year	3,436	3,578	$ 3,288
Funded (unfunded) status	(3,436)	(3,578)
Noncurrent assets	0	0
Current liabilities	(274)	(330)
Noncurrent liabilities	(3,162)	(3,248)
Asset (Liability) Recognized in the Consolidated Balance Sheets	$ (3,436)	$ (3,578)

Retirement Plans, Amounts Recog

Retirement Plans, Amounts Recognized in Accumulated Other Comprehensive Income Table (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Prior service cost	$ 122	$ 153
Net actuarial loss	32,879	23,124
Amount not yet recognized in net periodic benefit cost, but recognized in accumulated other comprehensive loss	33,001	23,277
Other Postretirement Benefit Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Prior service cost	0	0
Net actuarial loss	73	84
Amount not yet recognized in net periodic benefit cost, but recognized in accumulated other comprehensive loss	$ 73	$ 84

Retirement Plans, Other Changes

Retirement Plans, Other Changes in Plan Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Defined Benefit Plan Disclosure [Line Items]
Amortization of prior service cost	$ 50	$ 58	$ 72
Amortization of actuarial gain (loss)	(15,636)	(17,079)	40,148
Income tax (expense) benefit	5,873	6,507	(15,562)
Other comprehensive income (loss) on pension and postretirement obligations	(9,713)	(10,514)	$ 24,658
Other Postretirement Benefit Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Net gain (loss)	19	(483)
Amortization of prior service cost	0	0
Amortization of actuarial gain (loss)	0	(35)
Income tax (expense) benefit	(7)	199
Other comprehensive income (loss) on pension and postretirement obligations	12	(319)
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Net gain (loss)	(17,911)	(17,945)
Amortization of prior service cost	50	58
Amortization of actuarial gain (loss)	2,256	1,384
Income tax (expense) benefit	5,880	6,308
Other comprehensive income (loss) on pension and postretirement obligations	$ (9,725)	$ (10,195)

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, 2015	Dec. 31, 2014	Dec. 31, 2013
Pension Plan [Member]
Net period benefit cost for the pension and postretirement plans
Service cost	$ 11,257	$ 11,058	$ 12,078
Interest cost	6,617	7,132	6,237
Expected return on plan assets	(21,438)	(19,922)	(17,647)
Prior service cost	50	58	72
Actuarial (gain) loss	2,256	1,384	4,344
Total net pension cost	(1,258)	(290)	5,084
Other Postretirement Benefit Plan [Member]
Net period benefit cost for the pension and postretirement plans
Service cost	0	0	0
Interest cost	141	150	142
Prior service cost	0	0	0
Actuarial (gain) loss	0	(35)	0
Total net pension cost	$ 141	$ 115	$ 142

Retirement Plans, Weighted Aver

Retirement Plans, Weighted Average Assumptions used to Determine Benefit and Net Periodic Benefit Costs (Details)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Expected long-term rate of return on plan assets	7.50%	7.50%
Pension Plan [Member]
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract]
Discount rate	4.30%	4.00%
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	4.00%	4.80%
Rate of increase in compensation levels	4.00%	4.00%
Expected long-term rate of return on plan assets	7.50%	7.50%
Other Postretirement Benefit Plan [Member]
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract]
Discount rate	4.30%	4.00%
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Discount rate	4.00%	4.80%

Retirement Plans, Asset Allocat

Retirement Plans, Asset Allocation for Pension Plan Table (Details)	Dec. 31, 2015	Dec. 31, 2014
Defined Benefit Plan Disclosure [Line Items]
Total	100.00%	100.00%
Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Total	60.00%	64.00%
Debt Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Total	40.00%	35.00%
Other [Member]
Defined Benefit Plan Disclosure [Line Items]
Total	0.00%	1.00%

Retirement Plans, Fair Value of

Retirement Plans, Fair Value of Pension Plan Investments Table (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Pension Plan Investments
Money market account	$ 481	$ 2,868
Mutual funds	168,982	185,483
Common /collective trust funds	120,136	115,145
Total Pension Plan Investments	289,599	303,496
Fair Value, Inputs, Level 1 [Member]
Pension Plan Investments
Money market account	481	2,868
Mutual funds	168,982	185,483
Common /collective trust funds	0	0
Total Pension Plan Investments	169,463	188,351
Fair Value, Inputs, Level 2 [Member]
Pension Plan Investments
Money market account	0	0
Mutual funds	0	0
Common /collective trust funds	120,136	115,145
Total Pension Plan Investments	120,136	115,145
Fair Value, Inputs, Level 3 [Member]
Pension Plan Investments
Money market account	0	0
Mutual funds	0	0
Common /collective trust funds	0	0
Total Pension Plan Investments	$ 0	$ 0

Retirement Plans, Estimated Fut

Retirement Plans, Estimated Future Benefit Payments (Details) $ in Thousands	Dec. 31, 2015USD ($)
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
2,016	$ 14,218
2,017	13,885
2,018	12,825
2,019	12,580
2,020	12,767
2021 - 2025	66,722
Other Postretirement Benefit Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
2,016	274
2,017	257
2,018	263
2,019	250
2,020	247
2021 - 2025	$ 1,189

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, 2015	Dec. 31, 2014
Change in assumed health care cost
Effect on total of service and interest cost (increase)	$ 15	$ 13
Effect on total of service and interest cost (decrease)	(13)	(11)
Effect on postretirement benefit obligation (increase)	357	316
Effect on postretirement benefit obligation (decrease)	$ (310)	$ (277)

Retirement Plans (Details Textu

Retirement Plans (Details Textuals) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Retirements Plans [Line Items]
Retirement eligible age for participation	55 years
Years eligible of service for participation	5 years
Expected long-term rate of return on plan assets	7.50%	7.50%
Actual return on plan assets percentage	0.43%	5.89%
Total expense related to 401(k)	$ 11	$ 11	$ 10
Fair Value Of Plan Assets As A Percentage Of Net Benefit Obligation	169.00%	177.00%
Acturial Losses [Member]
Retirements Plans [Line Items]
Amounts to be amortized from AOCI next fiscal year	$ 1.9
Equity Securities [Member]
Retirements Plans [Line Items]
Plan asset allocation minimum percentage	50.00%
Plan asset allocation maximum percentage	70.00%
Debt Securities [Member]
Retirements Plans [Line Items]
Plan asset allocation minimum percentage	30.00%
Plan asset allocation maximum percentage	50.00%
Cash and Cash Equivalents [Member]
Retirements Plans [Line Items]
Plan asset allocation minimum percentage	0.00%
Plan asset allocation maximum percentage	5.00%
Cash and Cash Equivalents [Member] | Prior Service Cost [Member]
Retirements Plans [Line Items]
Amounts to be amortized from AOCI next fiscal year	$ 0.1
Alternative Securities [Member]
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	8.50%
Defined Benefit Plan, Health Care Cost Trend, Reduction in Trend Rate Minimum	0.25%
Defined Benefit Plan, Health Care Cost Trend, Reduction in Trend Rate Maximum	0.50%
Change in assumption	0.5%-0.25% lower in each succeeding year
Ultimate future rate	5.00%
Post-65 Health Care Trend [Member]
Retirements Plans [Line Items]
Health care trend rate assumption	8.00%
Defined Benefit Plan, Health Care Cost Trend, Reduction in Trend Rate Minimum	0.25%
Defined Benefit Plan, Health Care Cost Trend, Reduction in Trend Rate Maximum	0.50%
Change in assumption	0.5%-0.25% lower in each succeeding year
Ultimate future rate	5.00%

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, 2015	Dec. 31, 2014	Dec. 31, 2013
Current:
Federal	$ 82,449	$ 74,646	$ 50,628
State	2,560	1,000	2,653
Total current	85,009	75,646	53,281
Deferred:
Federal	(10,606)	(805)	16,409
State	7,084	10,695	9,511
Total deferred	(3,522)	9,890	25,920
Total income tax expense	$ 81,487	$ 85,536	$ 79,201

Income Taxes, Deferred Tax Asse

Income Taxes, Deferred Tax Assets and Liabilities Resulted in Deferred Taxes Table (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Gross deferred tax assets:
Allowance for loan losses	$ 106,258	$ 99,219
Allowance for other losses	10,906	11,609
Accrued liabilities	6,802	5,773
Deferred compensation	31,677	31,392
State net operating losses	14,154	22,640
Nonaccrual interest	1,901	2,383
Other	5,811	7,929
Total deferred tax assets	177,509	180,945
Gross deferred tax liabilities
FHLB stock dividends	2,165	6,367
Prepaid expenses	69,396	68,955
Goodwill	25,770	24,049
Mortgage banking activities	15,704	13,147
Deferred loan fee income	17,770	21,199
State deferred taxes	6,366	9,011
Lease financing	3,042	2,313
Bank premises and equipment	7,491	9,532
Other	9,062	5,501
Total deferred tax liabilities	156,766	160,074
Net deferred tax assets	20,743	20,871
Tax effect of unrealized (gain) loss related to available for sale securities	219	(10,902)
Tax effect of unrealized loss related to pension and postretirement benefits	20,404	14,468
Net tax effected items	20,623	3,566
Net deferred tax assets including items with tax effect recorded directly to OCI	$ 41,366	$ 24,437

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, 2015	Dec. 31, 2014	Dec. 31, 2013
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	(5.00%)	(4.60%)	(4.50%)
State income taxes (net of federal benefit)	2.30%	2.80%	2.90%
Bank owned life insurance	(1.20%)	(1.70%)	(1.50%)
Federal tax credits	(0.50%)	(1.40%)	(1.00%)
Tax reserve adjustments	(0.60%)	0.70%	(1.90%)
Other	0.20%	0.20%	0.60%
Effective income tax rate	30.20%	31.00%	29.60%

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, 2015	Dec. 31, 2014
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Balance at beginning of year	$ 9	$ 6
Additions (subtractions) for tax positions related to prior years	(2)	1
Additions for tax positions related to current year	2	2
Balance at end of year	$ 9	$ 9

Income Taxes (Details Textuals)

Income Taxes (Details Textuals) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
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	6	$ 6
Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued	2	3
Unrecognized Tax Benefits, Income Tax Penalties and Interest Expense	(1)	$ 1
State and Local Jurisdiction [Member]
Operating Loss Carryforwards [Line Items]
Operating tax loss carryforwards	179
Operating tax loss carryforwards from acquisitions	$ 32

Derivative and Hedging Activ105

Derivative and Hedging Activities, Derivative Instruments Not Designated as Hedging Instruments (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Derivative Instruments Not Designated as Hedging Instruments [Abstract]
Fair Value	$ 29,391	$ 33,023
Not Designated as Hedging Instrument [Member] | Other Assets [Member] | Interest rate lock commitments (mortgage) [Member]
Derivative Instruments Not Designated as Hedging Instruments [Abstract]
Notional Amount	271,530	126,379
Fair Value	958	1,947
Not Designated as Hedging Instrument [Member] | Other Assets [Member] | Forward commitments (mortgage) [Member]
Derivative Instruments Not Designated as Hedging Instruments [Abstract]
Notional Amount	231,798
Fair Value	403
Not Designated as Hedging Instrument [Member] | Other Assets [Member] | Purchased options (time deposit) [Member]
Derivative Instruments Not Designated as Hedging Instruments [Abstract]
Notional Amount	104,582	110,347
Fair Value	2,715	6,054
Not Designated as Hedging Instrument [Member] | Other Liabilities [Member] | Forward commitments (mortgage) [Member]
Derivative Instruments Not Designated as Hedging Instruments [Abstract]
Notional Amount		234,500
Fair Value		(2,435)
Not Designated as Hedging Instrument [Member] | Other Liabilities [Member] | Written options (time deposit) [Member]
Derivative Instruments Not Designated as Hedging Instruments [Abstract]
Notional Amount	104,582	110,347
Fair Value	(2,715)	(6,054)
Not Designated as Hedging Instrument [Member] | Trading Assets [Member] | Interest Rate-related instruments - customer and mirror [Member]
Derivative Instruments Not Designated as Hedging Instruments [Abstract]
Notional Amount	1,665,965	1,636,480
Fair Value	$ 29,391	$ 33,023
Receive Rate	1.56%	1.60%
Pay Rate	1.56%	1.60%
Maturity	41 months	42 months
Not Designated as Hedging Instrument [Member] | Trading Assets [Member] | Foreign currency exchange forwards [Member]
Derivative Instruments Not Designated as Hedging Instruments [Abstract]
Notional Amount	$ 72,976	$ 60,742
Fair Value	1,532	2,140
Not Designated as Hedging Instrument [Member] | Trading Assets [Member] | Commodity contract [Member]
Derivative Instruments Not Designated as Hedging Instruments [Abstract]
Notional Amount	44,380
Fair Value	1,269
Not Designated as Hedging Instrument [Member] | Trading Liabilities [Member] | Interest Rate-related instruments - customer and mirror [Member]
Derivative Instruments Not Designated as Hedging Instruments [Abstract]
Notional Amount	1,665,965	1,636,480
Fair Value	$ (30,886)	$ (35,372)
Receive Rate	1.56%	1.60%
Pay Rate	1.56%	1.60%
Maturity	41 months	42 months
Not Designated as Hedging Instrument [Member] | Trading Liabilities [Member] | Foreign currency exchange forwards [Member]
Derivative Instruments Not Designated as Hedging Instruments [Abstract]
Notional Amount	$ 65,649	$ 56,573
Fair Value	(1,398)	$ (1,957)
Not Designated as Hedging Instrument [Member] | Trading Liabilities [Member] | Commodity contract [Member]
Derivative Instruments Not Designated as Hedging Instruments [Abstract]
Notional Amount	44,256
Fair Value	$ (1,146)

Derivative and Hedging Activ106

Derivative and Hedging Activities, Income Statement Category of the Gains and Losses (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Capital market fees, net [Member] | Interest Rate-related instruments - customer and mirror [Member]
Gain (loss) on derivative instruments not designated as hedging instruments
Gain / (Loss) Recognized in Income	$ 854	$ 486
Capital market fees, net [Member] | Foreign currency exchange forwards [Member]
Gain (loss) on derivative instruments not designated as hedging instruments
Gain / (Loss) Recognized in Income	(49)	90
Capital market fees, net [Member] | Commodity contract [Member]
Gain (loss) on derivative instruments not designated as hedging instruments
Gain / (Loss) Recognized in Income	123
Mortgage banking, net [Member] | Interest rate lock commitments (mortgage) [Member]
Gain (loss) on derivative instruments not designated as hedging instruments
Gain / (Loss) Recognized in Income	(989)	1,531
Mortgage banking, net [Member] | Forward commitments (mortgage) [Member]
Gain (loss) on derivative instruments not designated as hedging instruments
Gain / (Loss) Recognized in Income	$ 2,838	$ (3,736)

Derivative and Hedging Activ107

Derivative and Hedging Activities (Details Textuals) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Investment securities and cash equivalents pledged as collateral	$ 9	$ 11
Derivative collateral right to reclaim cash	$ 22	$ 15

Balance Sheet Offsetting (Detai

Balance Sheet Offsetting (Details) - Interest Rate Contract [Member] - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	$ 1,466	$ 558
Gross amounts offset in the balance sheet	0	0
Net amounts presented in the balance sheet	1,466	558
Financial instruments	(1,466)	(558)
Collateral	0	0
Net amount	0	0
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	30,200	34,087
Gross amounts offset in the balance sheet	0	0
Net amounts presented in the balance sheet	30,200	34,087
Financial instruments	(1,466)	(558)
Collateral	(28,734)	(26,105)
Net amount	$ 0	$ 7,424

Commitments, Off-Balance She109

Commitments, Off-Balance Sheet Arrangements, and Contingent Liabilities, Summary of Lending Related and Other Commitments (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Summary of lending-related and other commitments
Standby letters of credit, fair value	$ 2,954	$ 3,542
Commitments to extend credit, excluding commitments to originate residential mortgage loans held for sale [Member]
Summary of lending-related and other commitments
Lending related commitments	7,402,518	6,884,411
Commercial Letters Of Credit [Member]
Summary of lending-related and other commitments
Lending related commitments	9,945	9,179
Standby Letters of Credit [Member]
Summary of lending-related and other commitments
Lending related commitments	296,508	353,292
Standby letters of credit, fair value	$ 3,000	$ 4,000

Commitments, Off-Balance She110

Commitments, Off-Balance Sheet Arrangements, and Contingent Liabilities (Details Textuals) $ in Thousands	Jan. 11, 2016USD ($)	May. 22, 2015USD ($)loan_production_officebranch	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)	Dec. 31, 2013USD ($)	Dec. 31, 2012USD ($)
Commitments, Off-Balance Sheet Arrangements, and Contingent Liabilities (Textuals) [Line Items]
Carrying value of investments			$ 52,000	$ 27,000
Commitments under unconsolidated projects			61,000	28,000
Commitment term		3 years
Mortgage loan commitment		$ 196,000
Number of branch opening commitments | branch		1
Number of loan production offices | loan_production_office		4
Conciliation agreement cost, commitment term		4 years
Loans repurchased under make whole requests			3,000	5,000
Loss reimbursement claims under make whole requests			133	734
Loans sold to outside investors original amount			19,900,000
Loans sold to outside investors remaining outstanding amount			7,500,000
Residential mortgage loans sold with recourse risk			68,000	46,000
Residential mortgage loans sold with credit recourse risk			132,000	178,000
Subsequent Event [Member] | The Official Committee of Unsecured Creditors of World Marketing Chicago LLC v Associated Bank [Member]
Commitments, Off-Balance Sheet Arrangements, and Contingent Liabilities (Textuals) [Line Items]
Damages sought	$ 6,000
Damages sought, cash	4,000
Damages sought, indebtedness	1,000
Subsequent Event [Member] | American Funds Service Company v Associated Bank [Member]
Commitments, Off-Balance Sheet Arrangements, and Contingent Liabilities (Textuals) [Line Items]
Damages sought	$ 600
Reserve for Off-balance Sheet Activities [Member]
Commitments, Off-Balance Sheet Arrangements, and Contingent Liabilities (Textuals) [Line Items]
Valuation allowance balance			24,400	24,900	$ 21,900	$ 21,800
Mortgage Repurchase Reserve [Member]
Commitments, Off-Balance Sheet Arrangements, and Contingent Liabilities (Textuals) [Line Items]
Valuation allowance balance			$ 1,197	$ 3,258	$ 5,737

Commitments, Off-Balance She111

Commitments, Off-Balance Sheet Arrangements, and Contingent Liabilities Residential Mortgage Repurchase Reserve (Details) - Mortgage Repurchase Reserve [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Residential mortgage repurchase reserve
Balance at beginning of year	$ 3,258	$ 5,737
Repurchase provision expense	428	505
Adjustments to provision expense	(2,450)	(2,250)
Charge offs, net	(39)	(734)
Balance at end of year	$ 1,197	$ 3,258

Parent Company Only Financia112

Parent Company Only Financial Information, Balance Sheet (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
ASSETS
Cash and due from banks	$ 374,921	$ 444,113
Investment securities available for sale, at fair value	4,967,414	5,396,812
Other assets	1,047,017	1,010,253
Total assets	27,715,021	26,821,774
LIABILITIES AND STOCKHOLDERS’ EQUITY
Commercial paper	67,978	74,297
Senior notes, at par	680,000	680,000
Subordinated notes, at par	250,000	250,000
Other Long-term Debt and Capitalized Costs	(875)	(143)
Total long-term funding	2,679,350	3,930,117
Accrued expenses and other liabilities	222,914	222,285
Total liabilities	24,777,775	24,021,523
Preferred equity	121,379	59,727
Common stock	1,642	1,665
Total stockholders’ equity	2,937,246	2,800,251	$ 2,891,290	$ 2,936,399
Total liabilities and stockholders’ equity	27,715,021	26,821,774
Parent Company [Member]
ASSETS
Cash and due from banks	610,862	523,103
Investment securities available for sale, at fair value	61,847	76,159
Investment in subsidiaries	3,211,685	3,166,080
Other assets	73,781	94,332
Total assets	3,958,175	3,859,674
LIABILITIES AND STOCKHOLDERS’ EQUITY
Commercial paper	67,978	74,297
Senior notes, at par	680,000	680,000
Subordinated notes, at par	250,000	250,000
Other Long-term Debt and Capitalized Costs	(875)	(143)
Total long-term funding	929,125	929,857
Accrued expenses and other liabilities	23,826	55,269
Total liabilities	1,020,929	1,059,423
Preferred equity	121,379	59,727
Common stock	2,815,867	2,740,524
Total stockholders’ equity	2,937,246	2,800,251
Total liabilities and stockholders’ equity	$ 3,958,175	$ 3,859,674

Parent Company Only Financia113

Parent Company Only Financial Information, Statement of Income (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
INCOME
Interest income on notes receivable	$ 615,627	$ 598,582	$ 587,526
Total income	1,004,687	971,286	958,642
EXPENSE
Income before income taxes	269,788	276,045	267,893
Income tax expense	81,487	85,536	79,201
Net income	188,301	190,509	188,692
Preferred stock dividends	(7,155)	(5,002)	(5,158)
Net income available to common equity	181,146	185,507	183,534
Parent Company [Member]
INCOME
Dividends from subsidiaries	205,000	223,000	262,000
Interest income on notes receivable	0	1,264	1,988
Other income	8,441	9,682	7,742
Total income	213,441	233,946	271,730
EXPENSE
Interest expense on short and long-term funding	39,576	24,847	27,167
Other expense	4,684	745	8,029
Total expense	(44,260)	(25,592)	(35,196)
Income before income taxes	169,181	208,354	236,534
Income tax expense	(1,665)	(5,801)	(7,086)
Income before equity in undistributed net income (loss) of subsidiaries	170,846	214,155	243,620
Equity in undistributed net income (loss) of subsidiaries	17,455	(23,646)	(54,928)
Net income	188,301	190,509	188,692
Preferred stock dividends	(7,155)	(5,002)	(5,158)
Net income available to common equity	$ 181,146	$ 185,507	$ 183,534

Parent Company Only Financia114

Parent Company Only Financial Information, Statement of Cash Flows (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
CASH FLOWS FROM OPERATING ACTIVITIES
Net income	$ 188,301	$ 190,509	$ 188,692
Adjustments to reconcile net income to net cash provided by operating activities:
Gain on sales of investment securities, net	(8,133)	(494)	(564)
Gain on sales of assets and impairment write-downs, net	(1,592)	(10,288)	(5,413)
Other, net	(10,513)	(4,203)	9,274
Net cash provided by operating activities	301,744	199,509	477,958
CASH FLOWS FROM INVESTING ACTIVITIES
Proceeds from sales of investment securities	1,601,947	102,011	136,152
Available for sale securities	(2,859,793)	(1,096,410)	(1,954,936)
Net cash used in investing activities	(1,534,356)	(2,118,605)	(1,253,234)
CASH FLOWS FROM FINANCING ACTIVITIES
Net increase (decrease) in short-term funding	(233,872)	327,362	(1,586,013)
Proceeds from issuance of long-term funding	250,000	996,030	2,500,000
Repayment of long-term funding	(1,500,035)	(155,066)	(427,430)
Proceeds from issuance of preferred shares	62,966	0	0
Proceeds from issuance of common stock for stock-based compensation plans	20,054	13,228	9,305
Purchase of preferred stock	(1,335)	(2,451)	(1,626)
Purchase of common stock returned to authorized but unissued	(93,000)	(150,498)	0
Purchase of treasury stock	(5,154)	(112,312)	(123,349)
Net cash provided by financing activities	674,230	2,348,918	639,648
Net increase (decrease) in cash and cash equivalents	(558,382)	429,822	(135,628)
Cash and cash equivalents at beginning of period	1,032,067	602,245	737,873
Cash and cash equivalents at end of period	473,685	1,032,067	602,245
Parent Company [Member]
CASH FLOWS FROM OPERATING ACTIVITIES
Net income	188,301	190,509	188,692
Adjustments to reconcile net income to net cash provided by operating activities:
(Increase) decrease in equity in undistributed net income of subsidiaries	(17,455)	23,646	54,928
Gain on sales of investment securities, net	0	(214)	(456)
Gain on sales of assets and impairment write-downs, net	(5,673)	(5,609)	(1,007)
Other, net	(10,997)	(14,022)	(103,954)
Net cash provided by operating activities	154,176	194,310	138,203
CASH FLOWS FROM INVESTING ACTIVITIES
Proceeds from sales of investment securities	13,962	88,844	55,445
Available for sale securities	0	0	(23,101)
Net decrease in notes receivable	0	46,594	3,049
Purchase of other assets, net of disposals	11,964	10,930	2,407
Net cash used in investing activities	25,926	146,368	37,800
CASH FLOWS FROM FINANCING ACTIVITIES
Net increase (decrease) in short-term funding	(6,319)	8,813	14,239
Proceeds from issuance of long-term funding	0	496,030	0
Repayment of long-term funding	0	(155,000)	(25,821)
Proceeds from issuance of preferred shares	62,966	0	0
Purchase of preferred stock	(1,335)	(2,451)	(1,626)
Cash dividends	(69,555)	(63,712)	(60,149)
Purchase of common stock returned to authorized but unissued	(93,000)	(150,498)	0
Purchase of treasury stock	(5,154)	(112,312)	(123,349)
Net cash provided by financing activities	(92,343)	34,098	(187,401)
Net increase (decrease) in cash and cash equivalents	87,759	374,776	(11,398)
Cash and cash equivalents at beginning of period	523,103	148,327	159,725
Cash and cash equivalents at end of period	$ 610,862	$ 523,103	$ 148,327

Fair Value Measurements, Assets

Fair Value Measurements, Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Investment securities available for sale:
Investment securities available for sale	$ 4,967,414	$ 5,396,812
Trading assets	32,192	35,163
Liabilities, Fair Value Disclosure [Abstract]
Trading liabilities	33,430	37,329
Fair Value, Measurements, Recurring [Member]
Investment securities available for sale:
Trading assets	36,268	43,164
Liabilities, Fair Value Disclosure [Abstract]
Trading liabilities	36,145	45,818
Fair Value, Measurements, Recurring [Member] | US Treasury Securities [Member]
Investment securities available for sale:
Investment securities available for sale	997	998
Fair Value, Measurements, Recurring [Member] | Obligations of state and political subdivisions (municipal securities) [Member]
Investment securities available for sale:
Investment securities available for sale		582,679
Fair Value, Measurements, Recurring [Member] | Government-Sponsored Enterprise (GSE) [Member]
Investment securities available for sale:
Investment securities available for sale	1,414,626	3,563,457
Fair Value, Measurements, Recurring [Member] | GNMA [Member]
Investment securities available for sale:
Investment securities available for sale	1,590,003	167,332
Fair Value, Measurements, Recurring [Member] | Private Label [Member]
Investment securities available for sale:
Investment securities available for sale	1,709	2,294
Fair Value, Measurements, Recurring [Member] | GNMA Commercial Mortgage-Related Securities [Member]
Investment securities available for sale:
Investment securities available for sale	1,955,310	1,073,893
Fair Value, Measurements, Recurring [Member] | Other Debt And Other Equity Securities [Member]
Investment securities available for sale:
Investment securities available for sale	4,769	6,159
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Investment securities available for sale:
Investment securities available for sale	2,566	3,957
Trading assets	0	0
Liabilities, Fair Value Disclosure [Abstract]
Trading liabilities	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | US Treasury Securities [Member]
Investment securities available for sale:
Investment securities available for sale	997	998
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Obligations of state and political subdivisions (municipal securities) [Member]
Investment securities available for sale:
Investment securities available for sale		0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Government-Sponsored Enterprise (GSE) [Member]
Investment securities available for sale:
Investment securities available for sale	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | GNMA [Member]
Investment securities available for sale:
Investment securities available for sale	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Private Label [Member]
Investment securities available for sale:
Investment securities available for sale	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | GNMA Commercial Mortgage-Related Securities [Member]
Investment securities available for sale:
Investment securities available for sale	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Other Debt And Other Equity Securities [Member]
Investment securities available for sale:
Investment securities available for sale	1,569	2,959
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Investment securities available for sale:
Investment securities available for sale	4,964,648	5,392,655
Trading assets	34,907	41,217
Liabilities, Fair Value Disclosure [Abstract]
Trading liabilities	36,145	43,383
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | US Treasury Securities [Member]
Investment securities available for sale:
Investment securities available for sale	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Obligations of state and political subdivisions (municipal securities) [Member]
Investment securities available for sale:
Investment securities available for sale		582,679
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Government-Sponsored Enterprise (GSE) [Member]
Investment securities available for sale:
Investment securities available for sale	1,414,626	3,563,457
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | GNMA [Member]
Investment securities available for sale:
Investment securities available for sale	1,590,003	167,332
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Private Label [Member]
Investment securities available for sale:
Investment securities available for sale	1,709	2,294
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | GNMA Commercial Mortgage-Related Securities [Member]
Investment securities available for sale:
Investment securities available for sale	1,955,310	1,073,893
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Other Debt And Other Equity Securities [Member]
Investment securities available for sale:
Investment securities available for sale	3,000	3,000
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Investment securities available for sale:
Investment securities available for sale	200	200
Trading assets	1,361	1,947
Liabilities, Fair Value Disclosure [Abstract]
Trading liabilities	0	2,435
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | US Treasury Securities [Member]
Investment securities available for sale:
Investment securities available for sale	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Obligations of state and political subdivisions (municipal securities) [Member]
Investment securities available for sale:
Investment securities available for sale		0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Government-Sponsored Enterprise (GSE) [Member]
Investment securities available for sale:
Investment securities available for sale	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | GNMA [Member]
Investment securities available for sale:
Investment securities available for sale	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Private Label [Member]
Investment securities available for sale:
Investment securities available for sale	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | GNMA Commercial Mortgage-Related Securities [Member]
Investment securities available for sale:
Investment securities available for sale	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Other Debt And Other Equity Securities [Member]
Investment securities available for sale:
Investment securities available for sale	$ 200	$ 200

Fair Value Measurements, Ass116

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, 2015	Dec. 31, 2014
Available-for-sale Securities [Member]
Assets and Liabilities Measured at Fair Value Using Significant Unobservable Inputs (Level 3)
Beginning Balance	$ 200	$ 299
Total net gain (losses) included in income:
Sales of investment securities		99
Total net gains included in other comprehensive income
Ending Balance	200	200
Fair Value, Net Derivative Asset (Liability Measure on Recurring Basis, Unobservable Input Reconciliation On Net Losses Included in Income [Abstract]
Mortgage derivative loss	0	0
Derivatives [Member]
Total net gain (losses) included in income:
Sales of investment securities		0
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Beginning Balance	(488)	1,717
Fair Value, Net Derivative Asset (Liability Measure on Recurring Basis, Unobservable Input Reconciliation On Net Losses Included in Income [Abstract]
Mortgage derivative loss	1,849	(2,205)
Ending Balance	$ 1,361	$ (488)

Fair Value Measurements, Ass117

Fair Value Measurements, Assets and Liabilities Measured at Fair Value on a Nonrecurring Basis (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Assets and Liabilities Measured at Fair Value on a Non-recurring Basis
Loans held for sale	$ 124,915	$ 156,423
Market valuation adjustment	(155)	0
Provision for Credit Losses, Impaired Loans	(7,796)	(17,272)
Mortgage servicing rights	61,341	60,145	$ 63,280
Mortgage Servicing Rights (MSR) Impairment (Recovery)	425	(321)	$ 14,563
Fair Value, Inputs, Level 1 [Member]
Assets and Liabilities Measured at Fair Value on a Non-recurring Basis
Loans held for sale	0	0
Fair Value, Inputs, Level 2 [Member]
Assets and Liabilities Measured at Fair Value on a Non-recurring Basis
Loans held for sale	124,915	156,423
Fair Value, Inputs, Level 3 [Member]
Assets and Liabilities Measured at Fair Value on a Non-recurring Basis
Loans held for sale	0	0
Fair Value, Measurements, Nonrecurring [Member]
Assets and Liabilities Measured at Fair Value on a Non-recurring Basis
Loans held for sale	124,915	156,423
Impaired loans	41,891	53,832
Mortgage servicing rights	70,686	66,342
Fair Value, Measurements, Nonrecurring [Member] | Fair Value, Inputs, Level 1 [Member]
Assets and Liabilities Measured at Fair Value on a Non-recurring Basis
Loans held for sale	0	0
Impaired loans	0	0
Mortgage servicing rights	0	0
Fair Value, Measurements, Nonrecurring [Member] | Fair Value, Inputs, Level 2 [Member]
Assets and Liabilities Measured at Fair Value on a Non-recurring Basis
Loans held for sale	124,915	156,423
Impaired loans	0	0
Mortgage servicing rights	0	0
Fair Value, Measurements, Nonrecurring [Member] | Fair Value, Inputs, Level 3 [Member]
Assets and Liabilities Measured at Fair Value on a Non-recurring Basis
Loans held for sale	0	0
Impaired loans	41,891	53,832
Mortgage servicing rights	$ 70,686	$ 66,342

Fair Value Measurements, Fair V

Fair Value Measurements, Fair Value of Financial Instruments (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Financial assets
Cash and due from banks	$ 374,921	$ 444,113
Cash and due from banks, Fair Value	374,921	444,113
Interest-bearing deposits in other financial institutions	79,764	571,924
Interest-bearing deposits in other financial institutions, fair value	79,764	571,924
Federal funds sold and securities purchased under agreements to resell	19,000	16,030
Federal funds sold and securities purchased under agreements to resell, fair value	19,000	16,030
Investment securities held to maturity	1,168,230	404,455
Investment securities held to maturity, fair value	1,184,442	413,067
Investment securities available for sale	4,967,414	5,396,812
Investment securities available for sale, at fair value	4,967,414	5,396,812
FHLB and Federal Reserve Bank stocks	147,240	189,107
Federal Home Loan Bank and Federal Reserve Bank stocks, fair value	147,240	189,107
Loans held for sale	124,915	154,935
Loans held for sale, fair value	124,915	156,423
Loans, net	18,440,079	17,327,544
Loans, net, fair value	18,389,832	17,427,647
Bank owned life insurance	583,019	574,154
Bank owned life insurance, fair value	583,019	574,154
Interest rate-related instruments	29,391	33,023
Interest rate-related agreements, fair value	29,391	33,023
Foreign currency exchange forwards	1,532	2,140
Foreign currency exchange forwards, fair value	1,532	2,140
Forward commitments to sell residential mortgage loans	958	1,947
Interest rate lock commitments to originate residential mortgage loans held for sale, fair value	958	1,947
Purchased options (time deposit)	2,715	6,054
Purchased options (time deposit), fair value	2,715	6,054
Commodity contracts	1,269
Commodity contracts, fair value	1,269
Forward Commitments, assets	403
Forward Commitments Fair Value Disclosure Assets	403
Financial liabilities
Noninterest-bearing demand, savings, interest-bearing demand, and money market accounts	19,444,863	17,192,049
Noninterest-bearing demand, savings, interest-bearing demand, and money market deposits, fair value	19,444,863	17,192,049
Brokered CDs and other time deposits	1,562,802	1,571,455
Brokered CDs and other time deposits, fair value	1,564,464	1,571,455
Short-term funding	834,416	1,068,288
Short-term funding, fair value	834,416	1,068,288
Long-term funding	2,679,350	3,930,117
Long-term funding, fair value	2,728,112	3,975,605
Interest rate-related instruments	30,886	35,372
Interest rate-related agreements, fair value	30,886	35,372
Foreign currency exchange forwards	1,398	1,957
Foreign currency exchange forwards, fair value	1,398	1,957
Standby letters of credit	2,954	3,542
Standby letters of credit, fair value	2,954	3,542
Forward commitments to sell residential mortgage loans		2,435
Forward commitments to sell residential mortgage loans, fair value		2,435
Written options (time deposit)	2,715	6,054
Written options (time deposit), fair value	2,715	6,054
Commodity Contract Liability	1,146
Commodity Contract Liability, Fair Value	1,146
Fair Value, Inputs, Level 1 [Member]
Financial assets
Cash and due from banks, Fair Value	374,921	444,113
Interest-bearing deposits in other financial institutions, fair value	79,764	571,924
Federal funds sold and securities purchased under agreements to resell, fair value	19,000	16,030
Investment securities held to maturity, fair value	0	0
Investment securities available for sale, at fair value	2,566	3,957
Federal Home Loan Bank and Federal Reserve Bank stocks, fair value	0	0
Loans held for sale, fair value	0	0
Loans, net, fair value	0	0
Bank owned life insurance, fair value	0	0
Interest rate-related agreements, fair value	0	0
Foreign currency exchange forwards, fair value	0	0
Interest rate lock commitments to originate residential mortgage loans held for sale, fair value	0	0
Purchased options (time deposit), fair value	0	0
Commodity contracts, fair value	0
Forward Commitments Fair Value Disclosure Assets	0
Financial liabilities
Noninterest-bearing demand, savings, interest-bearing demand, and money market deposits, fair value	0	0
Brokered CDs and other time deposits, fair value	0	0
Short-term funding, fair value	0	0
Long-term funding, fair value	0	0
Interest rate-related agreements, fair value	0	0
Foreign currency exchange forwards, fair value	0	0
Standby letters of credit, fair value	0	$ 0
Forward commitments to sell residential mortgage loans, fair value
Written options (time deposit), fair value	0	$ 0
Commodity Contract Liability, Fair Value	0
Fair Value, Inputs, Level 2 [Member]
Financial assets
Cash and due from banks, Fair Value	0	0
Interest-bearing deposits in other financial institutions, fair value	0	0
Federal funds sold and securities purchased under agreements to resell, fair value	0	0
Investment securities held to maturity, fair value	1,184,442	413,067
Investment securities available for sale, at fair value	4,964,648	5,392,655
Federal Home Loan Bank and Federal Reserve Bank stocks, fair value	147,240	189,107
Loans held for sale, fair value	124,915	156,423
Loans, net, fair value	0	0
Bank owned life insurance, fair value	583,019	574,154
Interest rate-related agreements, fair value	29,391	33,023
Foreign currency exchange forwards, fair value	1,532	2,140
Interest rate lock commitments to originate residential mortgage loans held for sale, fair value	0	0
Purchased options (time deposit), fair value	2,715	6,054
Commodity contracts, fair value	1,269
Forward Commitments Fair Value Disclosure Assets	0
Financial liabilities
Noninterest-bearing demand, savings, interest-bearing demand, and money market deposits, fair value	0	0
Brokered CDs and other time deposits, fair value	1,564,464	1,571,455
Short-term funding, fair value	834,416	1,068,288
Long-term funding, fair value	2,728,112	3,975,605
Interest rate-related agreements, fair value	30,886	35,372
Foreign currency exchange forwards, fair value	1,398	1,957
Standby letters of credit, fair value	2,954	3,542
Forward commitments to sell residential mortgage loans, fair value		0
Written options (time deposit), fair value	2,715	6,054
Commodity Contract Liability, Fair Value	1,146
Fair Value, Inputs, Level 3 [Member]
Financial assets
Cash and due from banks, Fair Value	0	0
Interest-bearing deposits in other financial institutions, fair value	0	0
Federal funds sold and securities purchased under agreements to resell, fair value	0	0
Investment securities held to maturity, fair value	0	0
Investment securities available for sale, at fair value	200	200
Federal Home Loan Bank and Federal Reserve Bank stocks, fair value	0	0
Loans held for sale, fair value	0	0
Loans, net, fair value	18,389,832	17,427,647
Bank owned life insurance, fair value	0	0
Interest rate-related agreements, fair value	0	0
Foreign currency exchange forwards, fair value	0	0
Interest rate lock commitments to originate residential mortgage loans held for sale, fair value	958	1,947
Purchased options (time deposit), fair value	0	0
Commodity contracts, fair value	0
Forward Commitments Fair Value Disclosure Assets	403
Financial liabilities
Noninterest-bearing demand, savings, interest-bearing demand, and money market deposits, fair value	19,444,863	17,192,049
Brokered CDs and other time deposits, fair value	0	0
Short-term funding, fair value	0	0
Long-term funding, fair value	0	0
Interest rate-related agreements, fair value	0	0
Foreign currency exchange forwards, fair value	0	0
Standby letters of credit, fair value	0	0
Forward commitments to sell residential mortgage loans, fair value		2,435
Written options (time deposit), fair value	0	$ 0
Commodity Contract Liability, Fair Value	$ 0

Fair Value Measurements (Detail

Fair Value Measurements (Details Textuals) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Fair Value Measurements (Textuals) [Abstract]
Other real estate owned measured at fair value	$ 11	$ 21
Write down of Other Real Estate Owned	3	2
Commitment on standby letters of credit	$ 297	$ 353
Fair Value of Assets and Liabilities [Line Items]
Closing ratio	91.00%
Weighted average discount rate	9.60%
Weighted average constant prepayment rate	12.20%
Maximum [Member]
Fair Value of Assets and Liabilities [Line Items]
Weighted average discount rate	20.00%
Minimum [Member]
Fair Value of Assets and Liabilities [Line Items]
Weighted average discount rate	10.00%

Regulatory Matters (Details)

Regulatory Matters (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Regulatory Capital [Abstract]
Common Equity Tier One Capital	$ 2,084,589
Common Equity Tier One Capital to Risk Weighted Assets	10.50%
Common Equity Tier One Capital Required for Capital Adequacy	$ 893,289
Common Equity Tier One Capital Required for Capital Adequacy to Risk Weighted Assets	4.50%
Parent Company [Member]
Regulatory Capital [Abstract]
Total Capital Actual Amount	$ 2,515,861	$ 2,350,898
Total Capital Actual Ratio	12.62%	12.66%
Total Capital for Capital Adequacy Purposes Amount	$ 1,594,397	$ 1,485,412
Total Capital for Adequacy Purposes Ratio	8.00%	8.00%
Tier 1 Capital Actual Amount	$ 2,016,861	$ 1,868,059
Tier 1 Capital Actual Ratio	10.12%	10.06%
Tier 1 Capital for Adequacy Purposes Amount	$ 797,199	$ 742,706
Tier 1 Capital for Adequacy Purposes Ratio	4.00%	4.00%
Common Equity Tier One Capital	$ 1,897,944
Common Equity Tier One Capital to Risk Weighted Assets	9.52%
Common Equity Tier One Capital Required for Capital Adequacy	$ 896,848
Common Equity Tier One Capital Required for Capital Adequacy to Risk Weighted Assets	4.50%
Tier 1 Leverage Capital Actual Amount	$ 2,016,861	$ 1,868,059
Tier 1 Leverage Capital Actual Ratio	7.60%	7.48%
Tier 1 Leverage Capital for Adequacy Purposes Amount	$ 1,061,325	$ 998,967
Tier 1 Leverage Capital for Adequacy Purposes Ratio	4.00%	4.00%
Subsidiaries [Member]
Regulatory Capital [Abstract]
Total Capital Actual Amount	$ 2,532,563	$ 2,449,514
Total Capital Actual Ratio	12.76%	13.26%
Total Capital for Capital Adequacy Purposes Amount	$ 1,588,070	$ 1,477,785
Total Capital for Adequacy Purposes Ratio	8.00%	8.00%
Total Capital to be Well Capitalized Amount	$ 1,985,088	$ 1,847,231
Total Capital to be Well Capitalized Ratio	10.00%	10.00%
Tier 1 Capital Actual Amount	$ 2,283,785	$ 2,217,861
Tier 1 Capital Actual Ratio	11.50%	12.01%
Tier 1 Capital for Adequacy Purposes Amount	$ 794,035	$ 738,892
Tier 1 Capital for Adequacy Purposes Ratio	4.00%	4.00%
Tier 1 Capital To Be Well Capitalized Amount	$ 1,191,053	$ 1,108,339
Tier 1 Capital To Be Well Capitalized Ratio	6.00%	6.00%
Tier 1 Equity Capital to be Well Capitalized Amount	$ 1,290,307
Tier 1 Equity Capital to be Well Capitalized Ratio	6.50%
Tier 1 Leverage Capital Actual Amount	$ 2,283,785	$ 2,217,861
Tier 1 Leverage Capital Actual Ratio	8.64%	8.92%
Tier 1 Leverage Capital for Adequacy Purposes Amount	$ 1,057,228	$ 994,103
Tier 1 Leverage Capital for Adequacy Purposes Ratio	4.00%	4.00%
Tier 1 Leverage Capital To Be Well Capitalized Amount	$ 1,321,535	$ 1,242,628
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, 2015USD ($)
Regulatory Capital Requirements [Abstract]
Required minimum cash and reserve balances	$ 64

Earnings Per Common Share (Deta

Earnings Per Common Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Calculations for basic and diluted earnings per common share
Net income	$ 188,301	$ 190,509	$ 188,692
Preferred stock dividends	(7,155)	(5,002)	(5,158)
Net income available to common equity	181,146	185,507	183,534
Common shareholder dividends	(61,774)	(58,123)	(54,505)
Unvested share-based payment awards	(626)	(587)	(486)
Undistributed earnings allocated to common shareholders	117,498	125,646	127,592
Undistributed earnings allocated to unvested share-based payment awards	1,248	1,151	951
Undistributed earnings	118,746	126,797	128,543
Basic
Distributed earnings to common shareholders	61,774	58,123	54,505
Undistributed earnings allocated to common shareholders	117,498	125,646	127,592
Total common shareholders earnings, basic	179,272	183,769	182,097
Diluted
Distributed earnings to common shareholders	61,774	58,123	54,505
Undistributed earnings allocated to common shareholders	117,498	125,646	127,592
Total common shareholders earnings, diluted	$ 179,272	$ 183,769	$ 182,097
Weighted average common shares outstanding (in shares)	149,350	157,286	165,584
Effect of dilutive common stock awards (in shares)	1,253	968	218
Diluted weighted average common shares outstanding (in shares)	150,603	158,254	165,802
Basic earnings (loss) per common share (in usd per share)	$ 1.20	$ 1.17	$ 1.10
Diluted earnings (loss) per common share (in usd per share)	$ 1.19	$ 1.16	$ 1.10
Earnings Per Share (Textuals) [Abstract]
Number of antidilutive stock options excluded from the computation of diluted earnings per share (in shares)	1,000	2,000	3,000

Segment Reporting (Details)

Segment Reporting (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Segment Income Statement Data Abstract
Net interest income	$ 676,278	$ 680,967	$ 645,543
Noninterest income	328,409	290,319	313,099
Total income	1,004,687	971,286	958,642
Provision for credit losses	37,500	16,000	10,100
Noninterest expense	697,399	679,241	680,649
Income before income taxes	269,788	276,045	267,893
Income tax expense	81,487	85,536	79,201
Net income	$ 188,301	$ 190,509	$ 188,692
Return on average allocated capital (ROCET1)	9.90%	9.90%	9.80%
Segment Balance Sheet Data
Average earning assets	$ 24,571,087	$ 22,760,128	$ 20,980,128
Average loans	18,252,264	16,838,994	15,663,145
Average deposits	19,903,087	17,647,084	17,438,195
Average allocated capital (CET1)	1,833,597	1,870,609	1,878,371
Operating Segments [Member] | Commercial Banking Segment [Member]
Segment Income Statement Data Abstract
Net interest income	310,072	296,717	321,346
Noninterest income	46,742	49,213	48,417
Total income	356,814	345,930	369,763
Provision for credit losses	41,913	46,857	55,297
Noninterest expense	141,912	148,476	140,744
Income before income taxes	172,989	150,597	173,722
Income tax expense	59,200	50,039	60,802
Net income	$ 113,789	$ 100,558	$ 112,920
Return on average allocated capital (ROCET1)	11.60%	11.10%	12.50%
Segment Balance Sheet Data
Average earning assets	$ 9,383,971	$ 8,927,401	$ 8,443,203
Average loans	9,374,191	8,915,498	8,433,389
Average deposits	5,856,530	5,148,195	5,479,567
Average allocated capital (CET1)	977,406	903,500	900,306
Operating Segments [Member] | Community, Consumer, and Business [Member]
Segment Income Statement Data Abstract
Net interest income	349,134	310,444	317,898
Noninterest income	265,638	221,379	247,667
Total income	614,772	531,823	565,565
Provision for credit losses	25,614	23,934	20,122
Noninterest expense	492,419	463,184	477,318
Income before income taxes	96,739	44,705	68,125
Income tax expense	33,859	15,647	23,843
Net income	$ 62,880	$ 29,058	$ 44,282
Return on average allocated capital (ROCET1)	9.80%	5.10%	7.80%
Segment Balance Sheet Data
Average earning assets	$ 8,810,015	$ 7,840,352	$ 7,225,943
Average loans	8,809,673	7,840,352	7,225,943
Average deposits	10,898,602	10,061,495	9,675,302
Average allocated capital (CET1)	640,181	564,303	570,634
Operating Segments [Member] | Risk Management and Shared Services [Member]
Segment Income Statement Data Abstract
Net interest income	17,072	73,806	6,299
Noninterest income	16,029	19,727	17,015
Total income	33,101	93,533	23,314
Provision for credit losses	(30,027)	(54,791)	(65,319)
Noninterest expense	63,068	67,581	62,587
Income before income taxes	60	80,743	26,046
Income tax expense	(11,572)	19,850	(5,444)
Net income	$ 11,632	$ 60,893	$ 31,490
Return on average allocated capital (ROCET1)	2.10%	13.90%	6.50%
Segment Balance Sheet Data
Average earning assets	$ 6,377,101	$ 5,992,375	$ 5,310,982
Average loans	68,400	83,144	3,813
Average deposits	3,147,955	2,437,394	2,283,326
Average allocated capital (CET1)	$ 216,010	$ 402,806	$ 407,431

Accumulated Other Comprehens124

Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	$ (4,850)
Personnel expense	(404,741)	$ (390,399)	$ (397,015)
Total other comprehensive income (loss)	(27,766)	19,394	(72,847)
Ending Balance	(32,616)	(4,850)
Accumulated Other Comprehensive Income (Loss) [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	(4,850)	(24,244)	48,603
Other comprehensive income (loss) before reclassifications	(38,331)	30,610	(122,403)
Amounts reclassified from accumulated other comprehensive income (loss):	(8,133)	(494)	(564)
Personnel expense	2,306	1,407	4,416
Interest income	(555)
Income tax (expense) benefit	16,947	(12,129)	45,704
Total other comprehensive income (loss)	(27,766)	19,394	(72,847)
Ending Balance	(32,616)	(4,850)	(24,244)
Investment Securities Available For Sale [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	18,512	(11,396)	86,109
Other comprehensive income (loss) before reclassifications	(20,439)	49,038	(158,207)
Amounts reclassified from accumulated other comprehensive income (loss):	(8,133)	(494)	(564)
Personnel expense	0	0	0
Interest income	(555)
Income tax (expense) benefit	11,074	(18,636)	61,266
Total other comprehensive income (loss)	(18,053)	29,908	(97,505)
Ending Balance	459	18,512	(11,396)
Defined Benefit Plans [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	(23,362)	(12,848)	(37,506)
Other comprehensive income (loss) before reclassifications	(17,892)	(18,428)	35,804
Amounts reclassified from accumulated other comprehensive income (loss):	0	0	0
Personnel expense	2,306	1,407	4,416
Interest income	0
Income tax (expense) benefit	5,873	6,507	(15,562)
Total other comprehensive income (loss)	(9,713)	(10,514)	24,658
Ending Balance	$ (33,075)	$ (23,362)	$ (12,848)