Webster Financial (WBS) 10-K 1 Mar 19 2018 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($) $ in Billions	12 Months Ended
	Dec. 31, 2018	Feb. 15, 2019
Document and Entity Information [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	FY
Trading Symbol	WBS
Entity Registrant Name	WEBSTER FINANCIAL CORPORATION
Entity Central Index Key	801,337
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		92,288,409
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Public Float	$ 5.8
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Assets [Abstract]
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	$ 260,422	$ 231,158
Interest-bearing deposits	69,077	25,628
Debt Securities, Available-for-sale	2,898,730	2,638,037
Investment securities held-to-maturity (fair value of $4,209,121 and $4,456,350)	4,325,420	4,487,392
Federal Home Loan Bank and Federal Reserve Bank stock	149,286	151,566
Loans held for sale (valued under fair value option $7,908 and $20,888)	11,869	20,888
Loans and leases	18,465,489	17,523,858
Allowance for loan and lease losses	(212,353)	(199,994)
Loans and leases, net	18,253,136	17,323,864
Deferred tax assets, net	96,516	92,630
Premises and equipment, net	124,850	130,001
Goodwill	538,373	538,373
Other intangible assets, net	25,764	29,611
Cash surrender value of life insurance policies	543,616	531,820
Accrued interest receivable and other assets	313,256	286,677
Total assets	27,610,315	26,487,645
Liabilities and Equity [Abstract]
Non-interest-bearing	4,162,446	4,191,496
Interest-bearing	17,696,399	16,802,233
Total deposits	21,858,845	20,993,729
Securities sold under agreements to repurchase and other borrowings	581,874	643,269
Advances from Federal Home Loan Banks	1,826,808	1,677,105
Long-term debt	226,021	225,767
Accrued expenses and other liabilities	230,252	245,817
Total liabilities	24,723,800	23,785,687
Shareholders’ equity:
Common stock, $.01 par value: Authorized - 200,000,000 shares; (Issued 93,651,601 shares)	937	937
Paid-in capital	1,114,394	1,122,164
Retained earnings	1,828,303	1,595,762
Treasury stock, at cost (1,508,456 and 1,658,526 shares)	(71,504)	(70,430)
Accumulated other comprehensive loss, net of tax	(130,652)	(91,531)
Total shareholders' equity	2,886,515	2,701,958
Total liabilities and shareholders' equity	27,610,315	26,487,645
Series F Preferred Stock [Member]
Shareholders’ equity:
Preferred stock, $.01 par value; Authorized - 3,000,000 shares: Series E issued and outstanding (5,060 shares) Series E issued and outstanding (5,060 shares)Series F issued and outstanding(6,000)Series E issued and outstanding (5,060 shares)	$ 145,037	$ 145,056

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Security held-to-maturity, fair value	$ 4,209,121	$ 4,456,350
Preferred Stock, Par or Stated Value Per Share	$ 0.01	$ 0.01
Preferred stock, shares authorized	3,000,000	3,000,000
Common stock par value (in usd per share)	$ 0.01	$ 0.01
Common stock, shares authorized	200,000,000	200,000,000
Common stock, shares issued	93,686,311	93,680,291
Treasury stock, shares	1,508,456	1,658,526
Series F Preferred Stock [Member]
Preferred Stock, Shares Outstanding	6,000

Consolidated Statements of Inco

Consolidated Statements of Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Interest Income:
Interest and fees on loans and leases	$ 842,449	$ 708,566	$ 621,028
Taxable interest and dividends on securities	191,493	181,131	180,346
Non-taxable interest on securities	20,597	22,874	19,090
Loans held for sale	628	1,034	1,449
Interest Expense:
Deposits	90,407	62,253	49,858
Securities sold under agreements to repurchase and other borrowings	13,491	14,365	14,528
Federal Home Loan Bank advances	33,461	30,320	29,033
Long-term debt	11,127	10,380	9,981
Total interest expense	148,486	117,318	103,400
Total interest income	1,055,167	913,605	821,913
Net interest income	906,681	796,287	718,513
Provision for loan and lease losses	42,000	40,900	56,350
Net interest income (loss) after provision for loan and lease losses	864,681	755,387	662,163
Non-interest Income:
Deposit service fees	162,183	151,137	140,685
Loan and lease related fees	32,025	26,448	26,581
Wealth and investment services	32,843	31,055	28,962
Mortgage banking activities	4,424	9,937	14,635
Increase in cash surrender value of life insurance policies	14,614	14,627	14,759
Debt Securities, Available-for-sale, Realized Gain (Loss)	0	0	414
Impairment loss on securities recognized in earnings	0	(126)	(149)
Other income	36,479	26,400	38,591
Total non-interest income	282,568	259,478	264,478
Non-interest Expense:
Compensation and benefits	381,496	356,505	325,998
Occupancy	59,463	60,490	61,110
Technology and equipment	97,877	89,464	79,882
Intangible assets amortization	3,847	4,062	5,652
Marketing	16,838	17,421	19,703
Professional and outside services	20,300	16,858	14,801
Deposit insurance	34,749	25,649	26,006
Other expense	91,046	90,626	90,039
Total non-interest expense	705,616	661,075	623,191
Income before income tax expense	441,633	353,790	303,450
Income tax expense	81,215	98,351	96,323
Net income	360,418	255,439	207,127
Preferred stock dividends and other	(8,715)	(8,608)	(8,704)
Earnings applicable to common shareholders	$ 351,703	$ 246,831	$ 198,423
Earnings per common share:
Earnings per common share, Basic (in dollars per share)	$ 3.83	$ 2.68	$ 2.17
Earnings per common share, Diluted (in dollars per share)	$ 3.81	$ 2.67	$ 2.16

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Statement of Comprehensive Income [Abstract]
Net income	$ 98,838	$ 99,673	$ 81,682	$ 80,225	$ 69,893	$ 64,496	$ 61,579	$ 59,471	$ 360,418	$ 255,439	$ 207,127
Other comprehensive (loss) income, net of tax:
Total available-for-sale securities									(43,427)	(7,590)	(9,069)
Total derivative instruments									5,703	4,565	5,912
Total defined benefit pension and postretirement benefit plans									(1,397)	4,135	4,270
Other comprehensive (loss) income, net of tax									(39,121)	1,110	1,113
Comprehensive income									$ 321,297	$ 256,549	$ 208,240

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Operating Activities:
Net income	$ 360,418	$ 255,439	$ 207,127
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for loan and lease losses	42,000	40,900	56,350
Deferred tax expense (benefit)	9,472	(9,074)	17,700
Depreciation and amortization	38,750	37,172	36,449
Amortization of earning assets and funding premium/discount, net	50,984	45,444	57,331
Stock-based compensation	11,612	12,276	11,438
Gain on sale, net of write-down, on foreclosed and repossessed assets	(709)	(784)	(976)
Loss (gain) on sale, net of write-down, on premises and equipment	346	(15)	397
Impairment loss on securities recognized in earnings	0	126	149
Gain on the sale of investment securities, net	0	0	(414)
Increase in cash surrender value of life insurance policies	(14,614)	(14,627)	(14,759)
Bank Owned Life Insurance Income	2,553	0	0
Mortgage banking activities	(4,424)	(9,937)	(14,635)
Proceeds from sale of loans held for sale	188,025	333,027	438,925
Originations of loans held for sale	(171,883)	(287,634)	(452,886)
Net decrease (increase) in derivative contract assets net of liabilities	(4,615)	32,763	27,929
Net Cash Provided by (Used in) Continuing Operations	(4,596)	0	0
Gain (Loss) on Disposition of Other Assets	0	0	7,331
Net (increase) decrease in accrued interest receivable and other assets	(739)	(19,790)	54,269
Net (decrease) increase in accrued expenses and other liabilities	(28,066)	29,680	(18,918)
Net cash provided by operating activities	469,408	444,966	398,145
Investing Activities:
Increase (Decrease) in Time Deposits	(43,449)	3,833	126,446
Purchases of available-for-sale securities	(873,108)	(660,106)	(980,870)
Proceeds from maturities and principal payments of available-for-sale securities	538,747	984,732	672,965
Proceeds from Sale of Debt Securities, Available-for-sale	0	0	259,283
Purchases of held-to-maturity securities	(393,693)	(1,043,278)	(1,066,156)
Proceeds from maturities and principal payments of held-to-maturity securities	524,862	687,439	795,953
Net proceeds from (purchase of) Federal Home Loan Bank stock	2,280	43,080	(6,299)
Purchases of intercompany debt securities	(1,215)	873	(381)
Net increase in loans	(990,014)	(549,213)	(1,440,141)
Proceeds from loans not originated for sale	1,687	14,679	34,170
Proceeds from life insurance policies	4,271	746	0
Proceeds from the sale of foreclosed properties and repossessed assets	8,011	7,603	9,205
Proceeds from the sale of premises and equipment	567	3,357	1,550
Additions to premises and equipment	(32,958)	(28,546)	(40,731)
Net (increase) decrease in interest-bearing deposits	(107,361)	0	0
Proceeds from Sale of Other Assets	0	7,581	0
Net cash provided by (used for) investing activities	(1,361,373)	(527,220)	(1,635,006)
Financing Activities:
Net increase in deposits	979,519	1,690,197	1,351,609
Proceeds from Other Debt	0	0	5,000
Proceeds from Federal Home Loan Bank advances	8,960,000	12,255,000	19,630,000
Repayments of Federal Home Loan Bank advances	(8,810,297)	(13,420,791)	(19,451,219)
Net decrease in securities sold under agreements to repurchase and other borrowings	(61,395)	(306,257)	(201,874)
Payments for Repurchase of Redeemable Preferred Stock	0	(122,710)	0
Proceeds from Issuance of Redeemable Preferred Stock	0	145,056	0
Dividends paid to common shareholders	(114,959)	(94,630)	(89,522)
Dividends paid to preferred shareholders	(7,875)	(8,096)	(8,096)
Exercise of stock options	2,173	8,259	11,762
Excess tax benefits from stock-based compensation	0	0	3,204
Common stock repurchased	(12,158)	(11,585)	(11,206)
Shares acquired related to employee share-based compensation plans	(13,779)	(11,694)	(11,664)
Common stock warrants repurchased	0	0	(163)
Net cash (used for) provided by financing activities	921,229	122,749	1,227,831
Net decrease in cash and due from banks	29,264	40,495	(9,030)
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Beginning Balance	231,158	190,663	199,693
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Ending Balance	260,422	231,158	190,663
Supplemental disclosure of cash flow information:
Interest paid	144,726	114,046	102,438
Income taxes paid	60,925	109,059	80,143
Noncash investing and financing activities:
Transfer of loans and leases to foreclosed properties and repossessed assets	8,105	8,972	6,769
Transfer of loans from portfolio to loans held for sale	$ 5,443	$ 7,234	$ 39,383

Consolidated Statement of Share

Consolidated Statement of Shareholder Equity Statement - USD ($) $ in Thousands	Total	Series E Preferred Stock [Member]	Series F Preferred Stock [Member]	Preferred Stock [Member]	Preferred Stock [Member]Series E Preferred Stock [Member]	Preferred Stock [Member]Series F Preferred Stock [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Retained Earnings [Member]Series E Preferred Stock [Member]	Retained Earnings [Member]Series F Preferred Stock [Member]	Treasury Stock [Member]	AOCI Attributable to Parent [Member]
Beginning Balance at Dec. 31, 2015	$ 2,413,960			$ 122,710			$ 937	$ 1,124,325	$ 1,315,948			$ (71,854)	$ (78,106)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	207,127								207,127
Other Comprehensive Income (Loss), Net of Tax	1,113												1,113
Dividends, Common Stock	89,913							(149)	90,062
Dividends, Preferred Stock		$ 8,096								$ 8,096
Stock Granted, Value, Share-based Compensation, Net of Forfeitures	14,092							2,976	403			10,713
Stock Issued During Period, Value, Stock Options Exercised	11,762							(1,350)				13,112
Adjustments Related to Tax Withholding for Share-based Compensation	11,664											11,664
Stock Repurchased During Period, Value	11,206											11,206
Stockholders' Equity, Other	163							163
Ending Balance at Dec. 31, 2016	2,527,012			122,710			937	1,125,937	1,425,320			(70,899)	(76,993)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	255,439								255,439
Other Comprehensive Income (Loss), Net of Tax	1,110												1,110
Dividends, Common Stock	94,929							(168)	95,097
Dividends, Preferred Stock		8,096								$ 8,096
Stock Granted, Value, Share-based Compensation, Net of Forfeitures	14,184							0	2,636			11,548
Stock Issued During Period, Value, Stock Options Exercised	8,259							(3,941)				12,200
Adjustments Related to Tax Withholding for Share-based Compensation	11,694											11,694
Stock Repurchased During Period, Value	11,585											11,585
Stockholders' Equity, Other			$ (88)								$ (88)
Stock Redeemed or Called During Period, Value		$ (122,710)			$ (122,710)
Stock Issued During Period, Value, New Issues			145,056			$ 145,056
Ending Balance at Dec. 31, 2017	2,701,958			145,056			937	1,122,164	1,595,762			(70,430)	(91,531)
Cumulative Effect of New Accounting Principle in Period of Adoption	0								15,648				(15,648)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	360,418								360,418
Other Comprehensive Income (Loss), Net of Tax	(39,121)												(39,121)
Dividends, Common Stock	115,343							(99)	115,442
Dividends, Preferred Stock			7,875								7,875
Stock Granted, Value, Share-based Compensation, Net of Forfeitures	11,612							(1,541)	3,275			9,878
Stock Issued During Period, Value, Stock Options Exercised	2,173							(5,762)				7,935
Stock Issued During Period, Value, Conversion of Units	0							(566)	(6,484)			7,050
Adjustments Related to Tax Withholding for Share-based Compensation	13,779											13,779
Stock Repurchased During Period, Value	12,158											12,158
Stock Issued During Period, Value, Other			(19)
Stockholders' Equity, Other			$ 22								$ 22
Ending Balance at Dec. 31, 2018	2,886,515			$ 145,037			$ 937	$ 1,114,394	1,828,303			$ (71,504)	(130,652)
Cumulative Effect of New Accounting Principle in Period of Adoption	$ (1,373)								$ (1,373)				$ (15,648)

Consolidated Statement of Sha_2

Consolidated Statement of Shareholder Equity Consolidated Statements of Shareholders' Equity (Parenthetical) - $ / shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Common Stock, Dividends, Per Share, Declared	$ 1.25	$ 1.03	$ 0.98
Series E Preferred Stock [Member]
Preferred Stock, Dividends Per Share, Declared	0	1,600
Series F Preferred Stock [Member]
Preferred Stock, Dividends Per Share, Declared	$ 1,323.4375	$ 0

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies Nature of Operations Webster Financial Corporation is a bank holding company and financial holding company under the BHC Act, incorporated under the laws of Delaware in 1986 and headquartered in Waterbury, Connecticut. At December 31, 2018 , Webster Financial Corporation's principal asset is all of the outstanding capital stock of Webster Bank. Webster delivers financial services to individuals, families, and businesses primarily within its regional footprint from New York to Massachusetts. Webster provides business and consumer banking, mortgage lending, financial planning, trust, and investment services through banking offices, ATMs, mobile banking and its internet website (www.websterbank.com or www.wbst.com). Webster also offers equipment financing, commercial real estate lending, and asset-based lending primarily across the Northeast. On a nationwide basis, through its HSA Bank division, Webster Bank offers and administers health savings accounts, flexible spending accounts, health reimbursement accounts, and commuter benefits. Basis of Presentation The accounting and reporting policies of the Company that materially affect its financial statements conform with GAAP, and to general practices within the financial services industry. The Consolidated Financial Statements and the accompanying Notes thereto include the accounts of Webster Financial Corporation and all other entities in which it has a controlling financial interest. Intercompany accounts and transactions have been eliminated in consolidation. Assets that the Company holds or manages in a fiduciary or agency capacity for customers, typically referred to as assets under administration or assets under management are not included in the accompanying Consolidated Balance Sheets since those assets are not Webster's, and the Company is not the primary beneficiary. Certain prior period amounts have been reclassified to conform to the current year's presentation. These reclassifications had an immaterial effect on the Company's consolidated financial statements. Principles of Consolidation The purpose of consolidated financial statements is to present the results of operations and the financial position of the Company and its subsidiaries as if the consolidated group were a single economic entity. In accordance with the applicable accounting guidance for consolidations, the consolidated financial statements include any voting interest entities (VOEs) in which the Company has a controlling financial interest and any variable interest entities (VIEs) for which the Company is deemed to be the primary beneficiary. The Company generally consolidates its VOEs if the Company, directly or indirectly, owns more than 50% of the outstanding voting shares of the entity and the non-controlling shareholders do not hold any substantive participating or controlling rights. A VIE is an entity that has either a total equity investment that is insufficient to finance its activities without additional subordinated financial support or whose equity investors lack the ability to control the entity’s activities or lack the ability to receive expected benefits or absorb obligations in a manner that is consistent with their investment in the entity. The Company evaluates each VIE to understand the purpose and design of the entity, and its involvement in the ongoing activities of the VIE and will consolidate the VIE if it has (i) the power to direct the activities of the VIE that most significantly affect the VIE's economic performance and (ii) an obligation to absorb losses of the VIE, or the right to receive benefits from the VIE, that could potentially be significant to the VIE. The Company accounts for unconsolidated partnerships and certain other investments using the equity method of accounting if it has the ability to significantly influence the operating and financial policies of the investee. This is generally presumed to exist when the Company owns between 20% and 50% of a corporation, or when it has greater than 3%-5% interest in a limited partnership or similarly structured entity. See Note 2: Variable Interest Entities for further information. Use of Estimates The preparation of financial statements in accordance with GAAP, requires management to make estimates and assumptions that affect the amounts of assets and liabilities as of the date of the financial statements as well as income and expense during the period. Actual results could differ from those estimates. Federal Deposit Insurance Corporation Assessment The Company reclassified certain loans under existing and modified FDIC loan category classifications in its regulatory filings, which resulted in an obligation for additional FDIC premiums for the period June 30, 2015 through December 31, 2017. During 2018, the Company made a $10.0 million payment to the FDIC to resolve its obligation. Cash Equivalents Cash equivalents have a maturity of three months or less. Cash and due from banks. Cash equivalents, including cash on hand, certain cash due from banks and deposits at the FRB of Boston, are referenced as cash and due from banks in the accompanying Consolidated Balance Sheets and Consolidated Statements of Cash Flows. Interest-bearing deposits. Cash equivalents, primarily representing deposits at the FRB of Boston in excess of reserve requirements, and federal funds sold, which essentially represent uncollateralized loans to other financial institutions, are referenced as interest-bearing deposits in the accompanying Consolidated Balance Sheets and Consolidated Statements of Cash Flows. The Company regularly evaluates the credit risk associated with those financial institutions to assure that Webster not become exposed to any significant credit risk on cash equivalents. Investment in Debt Securities Investment securities are classified as available-for-sale or held-to-maturity at the time of purchase. Any classification change subsequent to trade date is reviewed for compliance with corporate objectives and accounting policy. Debt securities classified as held-to-maturity are those which Webster has the ability and intent to hold to maturity. Securities classified as held-to-maturity are recorded at amortized cost net of unamortized premiums and discounts. Discount accretion income and premium amortization expense are recognized as interest income according to a constant yield methodology, with consideration given to prepayment assumptions on mortgage backed securities. Premiums are amortized to the earliest call date for debt securities purchased at a premium, with explicit, non-contingent call features and are callable at a fixed price and preset date. Securities classified as available-for-sale are recorded at fair value with unrealized gains and losses recorded as a component of other comprehensive income (OCI) or other comprehensive loss (OCL). Should securities be transferred from available-for-sale to held-to-maturity they would be recorded at fair value at the time of transfer and the respective gain or loss would be recorded as a separate component of OCI or OCL and amortized as an adjustment to interest income over the remaining life of such security. Securities classified as available-for-sale or held-to-maturity and in an unrealized loss position are evaluated for OTTI on a quarterly basis. The evaluation considers several qualitative factors, including the period of time the security has been in a loss position, and the amount of the unrealized loss. If the Company intends to sell a debt security or it is more likely than not the Company will be required to sell the debt security prior to recovery of its amortized cost basis, it is written down to fair value, and the loss is recognized in non-interest income. If the Company does not intend to sell the debt security and it is more likely than not that the Company will not be required to sell the debt security prior to recovery of its amortized cost basis, only the credit component of the unrealized loss is recorded as an impairment charge in non-interest income. The remaining loss component would be recorded to accumulated other comprehensive loss, net of tax (AOCL). The specific identification method is used to determine realized gains and losses on sales of securities. See Note 3: Investment Securities for further information. Investment in Equity Securities The Company’s accounting treatment for equity investments differs for those with and without readily determinable fair values. Equity investments with readily determinable fair values are recorded at fair value with changes in fair value recorded in non-interest income. For equity investments without readily determinable fair values, the Company elected the “measurement alternative,” and therefore carry these investments at cost, less impairment (if any), plus or minus changes in observable prices. Certain equity investments that do not have a readily available fair value may qualify for net asset value (NAV) measurement based on specific requirements. The Company's alternative investments accounted for at NAV consist of investments in non-public entities that generally cannot be redeemed since the Company’s investments are distributed as the underlying equity is liquidated. On a quarterly basis, the Company reviews its equity investments without readily determinable fair values for impairment. If the equity investment is considered impaired, an impairment loss equal to the amount by which the carrying value exceeds its fair value is recorded through a charge to earnings. The impairment loss may be reversed in a subsequent period if there are observable transactions for the identical or similar investment of the same issuer at a higher amount than the carrying amount that was established when the impairment was recognized. Impairment as well as upward or downward adjustments resulting from observable price changes in orderly transactions for identical or similar investments are included in non-interest income. Equity investments in entities that finance affordable housing and other community development projects provide a return primarily through the realization of tax benefits. The Company applies the proportional amortization method to account for its investments in qualified affordable housing projects. Investment in Federal Home Loan Bank and Federal Reserve Bank Stock Webster Bank is a member of the FHLB and the Federal Reserve System, and is required to maintain an investment in capital stock of the FHLB of Boston and FRB of Boston. Based on redemption provisions, the stock of both the FHLB and the FRB has no quoted market value and is carried at cost. Membership stock is reviewed for impairment as economic circumstances warrant special review. Loans Held for Sale Residential mortgage loans that are classified as held for sale at the time of origination are accounted for under the fair value option method. Loans not originated for sale but subsequently transferred to held for sale are valued at the lower of cost or fair value method of accounting and are valued on an individual asset basis. Any cost amount in excess of fair value is recorded as a valuation allowance and recognized as a reduction of other non-interest income. Gains or losses on the sale of loans held for sale are recorded as mortgage banking activities. Cash flows from the sale of loans that were originated specifically for resale are presented as operating cash flows. Cash flows from the sale of loans originated for investment then subsequently transferred to held for sale are presented as investing cash flows. See Note 5: Transfers of Financial Assets for further information. Transfers and Servicing of Financial Assets Transfers of financial assets are accounted for as sales when control over the assets has been surrendered. Control over transferred assets is generally considered to have been surrendered when: (i) the transferred assets are legally isolated from the Company or its consolidated affiliates, even in bankruptcy or other receivership; (ii) the transferee has the right to pledge or exchange the assets with no conditions that constrain the transferee and provide more than a trivial benefit to the Company; and (iii) the Company does not maintain the obligation or unilateral ability to reclaim or repurchase the assets. The Company sells financial assets in the normal course of business, the majority of which are residential mortgage loan sales, primarily to government-sponsored enterprises through established programs, commercial loan sales through participation agreements, and other individual or portfolio loan and securities sales. In accordance with accounting guidance for asset transfers, the Company considers any ongoing involvement with transferred assets in determining whether the assets can be derecognized from the balance sheet. With the exception of servicing and certain performance-based guarantees, the Company’s continuing involvement with financial assets sold is minimal and generally limited to market customary representation and warranty clauses covering certain characteristics of the mortgage loans sold and the Company's origination process. The gain or loss on sale depends on the previous carrying amount of the transferred financial assets, the consideration received, and any other assets obtained or liabilities incurred in exchange for the transferred assets. When the Company sells financial assets, it may retain servicing rights and/or other interests in the financial assets. Servicing assets and any other interests held by the Company are recorded at fair value upon transfer, and thereafter are carried at the lower of cost or fair value. See Note 5: Transfers of Financial Assets for further information. Loans and Leases Loans and leases are stated at the principal amount outstanding, net of amounts charged off, unearned income, unamortized premiums and discounts, and deferred loan and lease fees/costs which are recognized as yield adjustments using the interest method. These yield adjustments are amortized over the contractual life of the related loans and leases adjusted for prepayments when applicable. Interest on loans and leases is credited to interest income as earned based on the interest rate applied to principal amounts outstanding. Prepayment fees are recognized in non-interest income. Cash flows from loans and leases are presented as investing cash flows. Loans and leases are placed on non-accrual status when collection of principal and interest in accordance with contractual terms is doubtful, generally when principal or interest payments become 90 days delinquent, unless the loan or lease is well secured and in process of collection, or sooner if management concludes circumstances indicate that the borrower may be unable to meet contractual principal or interest payments. Residential real estate loans, excluding loans fully insured against loss and in the process of collection, and consumer loans are placed on non-accrual status at 90 days past due, or at the date when the Company is notified that the borrower is discharged in bankruptcy. A charge-off for the balance in excess of the fair value of the collateral less cost to sell, is recorded at 180 days if the loan balance exceeds the fair value of the collateral less costs to sell. Residential loans that are more than 90 days past due, fully insured against loss, and in the process of collection, remain accruing and are reported as 90 days or more past due and accruing. Commercial, commercial real estate loans, and equipment finance loans or leases are subject to a detailed review when 90 days past due to determine accrual status, or when payment is uncertain and a specific consideration is made to put a loan or lease on non-accrual status. When loans and leases are placed on non-accrual status, the accrual of interest is discontinued, and any unpaid accrued interest is reversed and charged against interest income. If ultimate repayment of a non-accrual loan or lease is expected, any payments received are applied in accordance with contractual terms. If ultimate repayment is not expected on commercial, commercial real estate, and equipment finance loans and leases, any payment received on a non-accrual loan or lease is applied to principal until the unpaid balance has been fully recovered. Any excess is then credited to interest income when received. If the Company determines, through a current valuation analysis, that principal can be repaid on residential real estate and consumer loans, interest payments may be taken into income as received on a cash basis. Loans are generally removed from non-accrual status when they become current as to principal and interest or demonstrate a period of performance under contractual terms and, in the opinion of management, are fully collectible as to principal and interest. Pursuant to regulatory guidance, a loan discharged under Chapter 7 of the U.S. bankruptcy code is removed from non-accrual status when the bank expects full repayment of the remaining pre-discharged contractual principal and interest, the loan is a closed-end amortizing loan, it is fully collateralized, and post-discharge the loan had at least six consecutive months of current payments. See Note 4: Loans and Leases for further information. Allowance for Loan and Lease Losses The ALLL is a reserve established through a provision for loan and lease losses charged to expense and represents management’s best estimate of probable losses that may be incurred within the existing loan and lease portfolio as of the balance sheet date. The level of the allowance reflects management’s view of trends in losses, current portfolio quality, and present economic, political, and regulatory conditions. The ALLL may be allocated for specific portfolio segments; however, the entire allowance balance is available to absorb credit losses inherent in the total loan and lease portfolio. A charge-off is recorded when all or a portion of the loan or lease is deemed to be uncollectible. Back-testing is performed to compare original estimated losses and actual observed losses, resulting in ongoing refinements. While management utilizes its best judgment based on the information available at the time, the ultimate adequacy of the allowance is dependent upon a variety of factors that are beyond the Company’s control, which include the performance of the Company’s portfolio, economic conditions, interest rate sensitivity, and other external factors. The ALLL consists of the following three elements: (i) specific valuation allowances established for probable losses on impaired loans and leases; (ii) quantitative valuation allowances calculated using loss experience for like loans and leases with similar characteristics and trends, adjusted, as necessary, to reflect the impact of current conditions; and (iii) qualitative factors determined based on general economic conditions and other factors that may be internal or external to the Company. Loans and leases are considered impaired when, based on current information and events, it is probable the Company will be unable to collect all amounts due in accordance with the original contractual terms of the loan agreement, including scheduled principal and interest payments. Impairment is evaluated on a pooled basis for smaller-balance homogeneous residential, consumer loans and small business loans. Commercial, commercial real estate, and equipment financing loans and leases over a specific dollar amount and all TDR are evaluated individually for impairment. A loan identified as a TDR is considered an impaired loan for the entire term of the loan, with few exceptions. If a loan is impaired, a specific valuation allowance may be established, and the loan is reported net, at the present value of estimated future cash flows using the loan’s original interest rate or at the fair value of collateral less cost to sell if repayment is expected from collateral liquidation. Interest payments on non-accruing impaired loans are typically applied to principal unless collectability of the principal amount is reasonably assured, in which case interest is recognized on a cash basis. Loans and leases, or portions thereof, are charged off when deemed uncollectible. Factors considered by management in determining impairment include payment status, collateral value, discharged bankruptcy, and the likelihood of collecting scheduled principal and interest payments. The current or weighted-average (for multiple notes within a commercial borrowing arrangement) interest rate of the loan is used as the discount rate, for determining net present value of the loan evaluated for impairment, when the interest rate floats with a specified index. A change in terms or payments would be included in the impairment calculation. See Note 4: Loans and Leases for further information. Reserve for Unfunded Commitments The reserve for unfunded commitments provides for probable losses inherent with funding the unused portion of legal commitments to lend. The unfunded reserve calculation includes factors that are consistent with the ALLL methodology for funded loans using the PD, LGD, and a draw down factor applied to the underlying borrower risk and facility grades. The reserve for unfunded credit commitments is included within other liabilities in the accompanying Consolidated Balance Sheets, and changes in the reserve are reported as a component of other non-interest expense in the accompanying Consolidated Statements of Income. See Note 21: Commitments and Contingencies for further information. Troubled Debt Restructurings A modified loan is considered a TDR when the following two conditions are met: (i) the borrower is experiencing financial difficulties; and (ii) the modification constitutes a concession. The Company considers all aspects of the restructuring in determining whether a concession has been granted, including the debtor's ability to access funds at a market rate. In general, a concession exists when the modified terms of the loan are more attractive to the borrower than standard market terms. Modified terms are dependent upon the financial position and needs of the individual borrower. The most common types of modifications include covenant modifications and forbearance. Loans for which the borrower has been discharged under Chapter 7 bankruptcy are considered collateral dependent TDR, impaired at the date of discharge, and charged down to the fair value of collateral less cost to sell, if management considers that loss potential likely exists. The Company’s policy is to place consumer loan TDR, except those that were performing prior to TDR status, on non-accrual status for a minimum period of six months. Commercial TDR are evaluated on a case-by-case basis for determination of whether or not to place them on non-accrual status. Loans qualify for return to accrual status once they have demonstrated performance with the restructured terms of the loan agreement for a minimum of six months. Initially, all TDRs are reported as impaired. Generally, TDRs are classified as impaired loans and reported as TDR for the remaining life of the loan. Impaired and TDR classification may be removed if the borrower demonstrates compliance with the modified terms for a minimum of six months and through a fiscal year-end and the restructuring agreement specifies a market rate of interest equal to that which would be provided to a borrower with similar credit at the time of restructuring. In the limited circumstance that a loan is removed from TDR classification, it is the Company’s policy to continue to base its measure of loan impairment on the contractual terms specified by the loan agreement. See Note 4: Loans and Leases for further information. Foreclosed and Repossessed Assets Real estate acquired through foreclosure or completion of a deed in lieu of foreclosure and other assets acquired through repossession are carried at the lower of cost or market value less estimated selling costs and are included within other assets in the accompanying Consolidated Balance Sheets. Independent appraisals generally are obtained to substantiate fair value and may be subject to adjustment based upon historical experience or specific geographic trends impacting the property. Within 90 days of a loan being foreclosed upon, the excess of loan balance over fair value less cost to sell is charged off against the ALLL. Subsequent write-downs in value, maintenance costs as incurred, and gains or losses upon sale are charged to non-interest expense in the accompanying Consolidated Statements of Income. Premises and Equipment Premises and equipment are carried at cost, less accumulated depreciation. Depreciation of premises and equipment is computed on a straight-line basis over the estimated useful lives of the assets, as follows: Minimum Maximum Building and Improvements 5 - 40 years Leasehold improvements 5 - 20 years (or term or lease, if shorter) Fixtures and equipment 5 - 10 years Data processing and software 3 - 7 years Repairs and maintenance costs are charged to non-interest expense as incurred. Premises and equipment that is actively marketed for sale is reclassified to assets held for disposition. The cost and accumulated depreciation relating to premises and equipment retired or otherwise disposed of are eliminated, and any resulting losses are charged to non-interest expense. See Note 6: Premises and Equipment for further information. Goodwill Goodwill represents the excess purchase price of businesses acquired over the fair value of the identifiable net assets acquired and is assigned to specific reporting units. Goodwill is not subject to amortization but rather is evaluated for impairment annually, or more frequently in interim periods if events occur or circumstances change indicating it would more likely than not result in a reduction of the fair value of a reporting unit below its carrying value. Goodwill is evaluated for impairment by performing a qualitative assessment to determine whether it is more likely than not that the fair value of the reporting unit is less than its carrying amount, including goodwill. If the qualitative assessment indicates it is more likely than not that the fair value of the reporting unit is less than its carrying amount, including goodwill, then a 2 Step quantitative process will be performed that will require the Company to utilize an equally weighted combined income and market approach to arrive at an indicated fair value range for the reporting unit. In Step 1, the fair value of a reporting unit is compared to its carrying amount, including goodwill, to ascertain if a goodwill impairment exists. If the fair value of the reporting unit exceeds its carrying amount, goodwill of the reporting unit is not considered impaired, and it is not necessary to continue to Step 2 of the impairment process. Otherwise, Step 2 is performed where the implied fair value of goodwill is compared to the carrying value of goodwill in the reporting unit. If a reporting unit's carrying value exceeds fair value, the difference is charged to non-interest expense. The Company applied the qualitative assessment for its reporting units during its annual impairment review this year to determine if the 2-step quantitative impairment test was necessary. Based on its qualitative assessment, the Company determined that there was no evidence of impairment to the balance of its goodwill. See Note 7: Goodwill and Other Intangible Assets for further information. Other Intangible Assets Other intangible assets represent purchased assets that lack physical substance but can be distinguished from goodwill because of contractual or other legal rights, or because the asset is capable of being sold or exchanged either separately or in combination with a related contract, asset, or liability. Other intangible assets with finite useful lives are amortized to non-interest expense over their estimated useful lives and are evaluated for impairment whenever events occur or circumstances change indicating the carrying amount of the asset may not be recoverable. Core deposit and customer relationship intangible assets are amortized over their estimated useful lives. See Note 7: Goodwill and Other Intangible Assets for further information. Cash Surrender Value of Life Insurance Investment in life insurance represents the cash surrender value of life insurance policies on certain current and former officers of Webster. Cash surrender value increases are recorded in non-interest income, decreases are the result of collection on the policies, with death benefit proceeds in excess of cash surrender value recorded in other non-interest income upon the death of an insured. Securities Sold Under Agreements to Repurchase These agreements are accounted for as secured financing transactions since Webster maintains effective control over the transferred investment securities and the transfer meets the other criteria for such accounting. Obligations to repurchase the sold investment securities are reflected as a liability in the accompanying Consolidated Balance Sheets. The investment securities underlying the agreements are delivered to a custodial account for the benefit of the dealer or bank with whom each transaction is executed. The dealers or banks, which may sell, loan, or otherwise hypothecate such securities to other parties in the normal course of their operations, agree to resell to Webster the same securities at the maturity date of the agreements. The investment securities underlying the agreements with Bank customers are pledged; however, the customer does not have ability to hypothecate the underlying securities. See Note 10: Borrowings for further information. Revenue From Contracts With Customers Revenue from contracts with customers generally comprises non-interest income earned by the Company in exchange for services provided to customers and is recognized when services are complete or as they are rendered. These revenue streams include deposit service fees, wealth and investment services, and an insignificant component of other non-interest income in the accompanying Consolidated Statements of Income. The Company identifies the performance obligations included in the contracts with customers, determines the transaction price, allocates the transaction price to the performance obligations, as applicable, and recognizes revenue when performance obligations are satisfied. Services provided over a period of time are typically transferred to customers evenly over the term of the contracts and revenue is recognized evenly over the period services are provided. Contract receivables are included in accrued interest receivable and other assets. Payment terms vary by services offered, and the time between completion of performance obligations and payment is typically not significant. See Note 20: Revenue from Contracts with Customers for further information. Share-Based Compensation Webster maintains stock compensation plans under which restricted stock, restricted stock units, non-qualified stock options, incentive stock options, or stock appreciation rights may be granted to employees and directors. Share awards are issued from available treasury shares. Share-based compensation cost is recognized over the vesting period, is based on the grant-date fair value, net of a reduction for estimated forfeitures which is adjusted for actual forfeitures as they occur, and is reported as a component of compensation and benefits expense. Awards are generally subject to a 3 -year vesting period, while certain conditions provide for a 1 -year vesting period. Excess tax benefits result when tax return deductions exceed recognized compensation cost determined using the grant-date fair value approach for financial statement purposes. For restricted stock and restricted stock unit awards, fair value is measured using the Company's common stock closing price at the date of grant. For certain performance-based restricted stock awards, fair value is measured using the Monte Carlo valuation methodology, which provides for the 3 -year performance period. Awards ultimately vest in a range from zero to 150% of the target number of shares under the grant. Compensation expense is subject to adjustment based on management's assessment of Webster's return on equity performance relative to the target number of shares condition. Stock option awards use the Black-Scholes Option-Pricing Model to measure fair value at the date of grant. Dividends are paid on the time-based sha

Investment Securities

Investment Securities	12 Months Ended
	Dec. 31, 2018
Investments, Debt and Equity Securities [Abstract]
Investment Securities	Investment Securities A Summary of the amortized cost and fair value of investment securities is presented below: At December 31, 2018 2017 (In thousands) Amortized Cost Unrealized Gains Unrealized Losses Fair Value Amortized Cost Unrealized Gains Unrealized Losses Fair Value Available-for-sale: U.S. Treasury Bills $ 7,549 $ 1 $ — $ 7,550 $ 1,247 $ — $ — $ 1,247 Agency CMO 238,968 412 (4,457 ) 234,923 308,989 1,158 (3,814 ) 306,333 Agency MBS 1,521,534 1,631 (42,076 ) 1,481,089 1,124,960 2,151 (19,270 ) 1,107,841 Agency CMBS 608,167 — (41,930 ) 566,237 608,276 — (20,250 ) 588,026 CMBS 447,897 645 (2,961 ) 445,581 358,984 2,157 (74 ) 361,067 CLO 114,641 94 (1,964 ) 112,771 209,075 910 (134 ) 209,851 Single issuer-trust preferred — — — — 7,096 — (46 ) 7,050 Corporate debt 55,860 — (5,281 ) 50,579 56,504 797 (679 ) 56,622 Total available-for-sale $ 2,994,616 $ 2,783 $ (98,669 ) $ 2,898,730 $ 2,675,131 $ 7,173 $ (44,267 ) $ 2,638,037 Held-to-maturity: Agency CMO $ 208,113 $ 287 $ (5,255 ) $ 203,145 $ 260,114 $ 664 $ (4,824 ) $ 255,954 Agency MBS 2,517,823 8,250 (79,701 ) 2,446,372 2,569,735 16,989 (37,442 ) 2,549,282 Agency CMBS 667,500 53 (22,572 ) 644,981 696,566 — (10,011 ) 686,555 Municipal bonds and notes 715,041 2,907 (18,285 ) 699,663 711,381 8,584 (6,558 ) 713,407 CMBS 216,943 405 (2,388 ) 214,960 249,273 2,175 (620 ) 250,828 Private Label MBS — — — — 323 1 — 324 Total held-to-maturity $ 4,325,420 $ 11,902 $ (128,201 ) $ 4,209,121 $ 4,487,392 $ 28,413 $ (59,455 ) $ 4,456,350 Other-Than-Temporary Impairment The amount in the amortized cost columns in the table above includes other-than-temporary impairment related to certain CLO positions that were previously considered Covered Funds as defined by Section 619 of the Dodd-Frank Act, commonly known as the Volcker Rule. The Company has taken measures to bring its CLO positions into conformance with the Volcker Rule. The following table presents the changes in OTTI: Years ended December 31, (In thousands) 2018 2017 2016 Beginning balance $ 1,364 $ 3,243 $ 3,288 Reduction for investment securities called (542 ) (2,005 ) (194 ) Additions for OTTI not previously recognized in earnings — 126 149 Ending balance $ 822 $ 1,364 $ 3,243 To the extent that changes occur in interest rates, credit movements, and other factors that impact fair value and expected recovery of amortized cost of its investment securities, the Company may, in future periods, be required to recognize OTTI in earnings. Fair Value and Unrealized Losses The following tables provide information on fair value and unrealized losses for the individual investment securities with an unrealized loss, aggregated by classification and length of time that the individual investment securities have been in a continuous unrealized loss position: At December 31, 2018 Less Than Twelve Months Twelve Months or Longer Total (Dollars in thousands) Fair Value Unrealized Losses Fair Value Unrealized Losses # of Holdings Fair Value Unrealized Losses Available-for-sale: Agency CMO $ 15,524 $ (72 ) $ 180,641 $ (4,385 ) 36 $ 196,165 $ (4,457 ) Agency MBS 321,678 (2,078 ) 975,084 (39,998 ) 184 1,296,762 (42,076 ) Agency CMBS — — 566,237 (41,930 ) 37 566,237 (41,930 ) CMBS 343,457 (2,937 ) 5,193 (24 ) 39 348,650 (2,961 ) CLO 83,305 (1,695 ) 14,873 (269 ) 5 98,178 (1,964 ) Single issuer-trust preferred — — — — — — — Corporate debt 35,990 (1,820 ) 14,589 (3,461 ) 8 50,579 (5,281 ) Total available-for-sale in an unrealized loss position $ 799,954 $ (8,602 ) $ 1,756,617 $ (90,067 ) 309 $ 2,556,571 $ (98,669 ) Held-to-maturity: Agency CMO $ 691 $ (1 ) $ 182,396 $ (5,254 ) 25 $ 183,087 $ (5,255 ) Agency MBS 288,635 (1,916 ) 1,892,951 (77,785 ) 272 2,181,586 (79,701 ) Agency CMBS — — 635,284 (22,572 ) 56 635,284 (22,572 ) Municipal bonds and notes 68,351 (882 ) 414,776 (17,403 ) 223 483,127 (18,285 ) CMBS 24,881 (270 ) 132,464 (2,118 ) 20 157,345 (2,388 ) Total held-to-maturity in an unrealized loss position $ 382,558 $ (3,069 ) $ 3,257,871 $ (125,132 ) 596 $ 3,640,429 $ (128,201 ) At December 31, 2017 Less Than Twelve Months Twelve Months or Longer Total (Dollars in thousands) Fair Value Unrealized Losses Fair Value Unrealized Losses # of Holdings Fair Value Unrealized Losses Available-for-sale: Agency CMO $ 81,001 $ (449 ) $ 119,104 $ (3,365 ) 27 $ 200,105 $ (3,814 ) Agency MBS 416,995 (2,920 ) 606,021 (16,350 ) 135 1,023,016 (19,270 ) Agency CMBS 54,182 (851 ) 533,844 (19,399 ) 36 588,026 (20,250 ) CMBS 23,869 (74 ) — — 6 23,869 (74 ) CLO 56,335 (134 ) — — 3 56,335 (134 ) Single issuer-trust preferred 7,050 (46 ) — — 1 7,050 (46 ) Corporate debt 11,082 (395 ) 6,265 (284 ) 4 17,347 (679 ) Total available-for-sale in an unrealized loss position $ 650,514 $ (4,869 ) $ 1,265,234 $ (39,398 ) 212 $ 1,915,748 $ (44,267 ) Held-to-maturity: Agency CMO $ 98,090 $ (1,082 ) $ 106,775 $ (3,742 ) 22 $ 204,865 $ (4,824 ) Agency MBS 762,107 (4,555 ) 1,197,839 (32,887 ) 205 1,959,946 (37,442 ) Agency CMBS 576,770 (7,599 ) 109,785 (2,412 ) 56 686,555 (10,011 ) Municipal bonds and notes 6,432 (38 ) 226,861 (6,520 ) 92 233,293 (6,558 ) CMBS 92,670 (413 ) 14,115 (207 ) 13 106,785 (620 ) Total held-to-maturity in an unrealized loss position $ 1,536,069 $ (13,687 ) $ 1,655,375 $ (45,768 ) 388 $ 3,191,444 $ (59,455 ) Impairment Analysis The following impairment analysis summarizes the basis for evaluating if investment securities within the Company’s available-for-sale and held-to-maturity portfolios are impaired as of December 31, 2018 . Unless otherwise noted for an investment security type, management does not intend to sell these investment securities and has determined, based upon available evidence, that it is more likely than not that the Company will not be required to sell these investment securities before the recovery of their amortized cost. As such, based on the following impairment analysis, the Company does not consider any of these investment securities, in unrealized loss positions, to be other-than-temporarily impaired at December 31, 2018 . Available-for-Sale Securities Agency CMO. There were unrealized losses of $4.5 million on the Company’s investment in Agency CMO at December 31, 2018 , compared to $3.8 million at December 31, 2017 . Unrealized losses increased due to higher market rates while principal balances decreased for this asset class since December 31, 2017 . These investments are issued by a government or government sponsored agency and therefore, are backed by certain government guarantees, either direct or implicit. There has been no change in the credit quality, and the contractual cash flows are performing as expected. Agency MBS. There were unrealized losses of $42.1 million on the Company’s investment in residential mortgage-backed securities issued by government agencies at December 31, 2018 , compared to $19.3 million at December 31, 2017 . Unrealized losses increased due to higher market rates, while principal balances increased for this asset class since December 31, 2017 . These investments are issued by a government or government sponsored agency and therefore, are backed by certain government guarantees, either direct or implicit. There has been no change in the credit quality, and the contractual cash flows are performing as expected. Agency CMBS. There were unrealized losses of $41.9 million on the Company's investment in commercial mortgage-backed securities issued by government agencies at December 31, 2018 , compared to $20.3 million at December 31, 2017 . Unrealized losses increased due to higher market rates while principal balances remained approximately the same for this asset class since December 31, 2017 . These investments are issued by a government or government sponsored agency and therefore, are backed by certain government guarantees, either direct or implicit. There has been no change in the credit quality, and the contractual cash flows are performing as expected. CMBS. There were unrealized losses of $3.0 million on the Company’s investment in CMBS at December 31, 2018 , compared to $0.1 million at December 31, 2017 . The portfolio of mainly floating rate CMBS experienced increased market spreads which resulted in lower market prices and higher unrealized losses at December 31, 2018 compared to December 31, 2017 . Internal stress tests are performed on individual bonds to monitor potential losses under stress scenarios. Contractual cash flows for the bonds continue to perform as expected. CLO. There were unrealized losses of $2.0 million on the Company’s investments in CLO at December 31, 2018 compared to $0.1 million unrealized losses at December 31, 2017 . Unrealized losses increased due to increased market spreads while principal balances decreased due to call activity since December 31, 2017 . Contractual cash flows for the bonds continue to perform as expected. Corporate debt. There were $5.3 million of unrealized losses on the Company's corporate debt portfolio at December 31, 2018 , compared to $0.7 million at December 31, 2017 . Unrealized losses increased due to increased market spreads since December 31, 2017 . The Company performs periodic credit reviews of the issuer to assess the likelihood for ultimate recovery of amortized cost. Held-to-Maturity Securities Agency CMO. There were unrealized losses of $5.3 million on the Company’s investment in Agency CMO at December 31, 2018 , compared to $4.8 million at December 31, 2017 . Unrealized losses increased due to higher market rates while principal balances decreased since December 31, 2017 . These investments are issued by a government or government sponsored agency and therefore, are backed by certain government guarantees, either direct or implicit. There has been no change in the credit quality, and the contractual cash flows are performing as expected. Agency MBS. There were unrealized losses of $79.7 million on the Company’s investment in residential mortgage-backed securities issued by government agencies at December 31, 2018 , compared to $37.4 million at December 31, 2017 . Unrealized losses increased due to higher market rates while principal balances increased for this asset class since December 31, 2017 . These investments are issued by a government or government sponsored agency and therefore, are backed by certain government guarantees, either direct or implicit. There has been no change in the credit quality, and the contractual cash flows are performing as expected. Agency CMBS. There were unrealized losses of $22.6 million on the Company’s investment in commercial mortgage-backed securities issued by government agencies at December 31, 2018 , compared to $10.0 million at December 31, 2017 . Unrealized losses increased due to higher market rates while principal balances increased since December 31, 2017 . These investments are issued by a government or government sponsored agency and therefore, are backed by certain government guarantees, either direct or implicit. There has been no change in the credit quality, and the contractual cash flows are performing as expected. Municipal bonds and notes. There were unrealized losses of $18.3 million on the Company’s investment in municipal bonds and notes at December 31, 2018 , compared to $6.6 million at December 31, 2017 . Unrealized losses increased due to higher market rates while principal balances increased since December 31, 2017 . The Company performs periodic credit reviews of the issuers and the securities are currently performing as expected. CMBS. There were unrealized losses of $2.4 million on the Company’s investment in CMBS at December 31, 2018 , compared to $0.6 million unrealized losses at December 31, 2017 . Unrealized losses increased due to higher market rates on mainly seasoned fixed rate conduit transactions while principal balances decreased since December 31, 2017 . Internal stress tests are performed on individual bonds to monitor potential losses under stress scenarios. Sales of Available-for Sale Securities There were no sales during the years ended December 31, 2018 and 2017 . For the year ended December 31, 2016 , proceeds from sales were $259.3 million , with gross realized gains of $2.9 million less gross realized losses of $2.5 million resulting in a gain on sale of investment securities, net of $0.4 million . Contractual Maturities The amortized cost and fair value of debt securities by contractual maturity are set forth below: At December 31, 2018 Available-for-Sale Held-to-Maturity (In thousands) Amortized Cost Fair Value Amortized Cost Fair Value Due in one year or less $ 27,880 $ 27,865 $ 7,047 $ 7,059 Due after one year through five years 17,126 17,155 7,909 8,019 Due after five through ten years 275,969 274,027 31,455 31,500 Due after ten years 2,673,641 2,579,683 4,279,009 4,162,543 Total debt securities $ 2,994,616 $ 2,898,730 $ 4,325,420 $ 4,209,121 For the maturity schedule above, mortgage-backed securities and CLO, which are not due at a single maturity date, have been categorized based on the maturity date of the underlying collateral. Actual principal cash flows may differ from this maturity date presentation as borrowers have the right to prepay obligations with or without prepayment penalties. At December 31, 2018 , the Company had a carrying value of $1.2 billion in callable debt securities in its CMBS, CLO, and municipal bond portfolios. The Company considers prepayment risk in the evaluation of its interest rate risk profile. These maturities may not reflect actual durations, which may be impacted by prepayments. Investment securities with a carrying value totaling $2.2 billion at December 31, 2018 and $2.4 billion at December 31, 2017

Variable Interest Entities

Variable Interest Entities	12 Months Ended
	Dec. 31, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Variable Interest Entities	The Company has an investment interest in the following entities that meet the definition of a VIE. Consolidated Rabbi Trust. The Company established a Rabbi Trust to meet the obligations due under its Deferred Compensation Plan for Directors and Officers and to mitigate the expense volatility of the aforementioned plan. The funding of the Rabbi Trust and the discontinuation of the Deferred Compensation Plan for Directors and Officers occurred during 2012. Investments held in the Rabbi Trust primarily consist of mutual funds that invest in equity and fixed income securities. The Company is considered the primary beneficiary of the Rabbi Trust as it has the power to direct the activities of the Rabbi Trust that significantly affect the VIE's economic performance and it has the obligation to absorb losses of the VIE that could potentially be significant to the VIE. The Company consolidates the invested assets of the trust along with the total deferred compensation obligations and includes them in accrued interest receivable and other assets and accrued expenses and other liabilities, respectively, in the accompanying Consolidated Balance Sheets. Earnings in the Rabbi Trust, including appreciation or depreciation, are reflected as other non-interest income, and changes in the corresponding liability are reflected as compensation and benefits, in the accompanying Consolidated Statements of Income. Refer to Note 16: Fair Value Measurements for additional information. Non-Consolidated Securitized Investments. The Company, through normal investment activities, makes passive investments in securities issued by VIEs for which Webster is not the manager. The investment securities consist of Agency CMO, Agency MBS, Agency CMBS, CMBS, and CLO. The Company has not provided financial or other support with respect to these investment securities other than its original investment. For these investment securities, the Company determined it is not the primary beneficiary due to the relative size of its investment in comparison to the principal amount of the structured securities issued by the VIEs, the level of credit subordination which reduces the Company’s obligation to absorb losses or right to receive benefits and its inability to direct the activities that most significantly impact the economic performance of the VIEs. The Company’s maximum exposure to loss is limited to the amount of its investment in the VIEs. Refer to Note 3: Investment Securities for additional information. Tax Credit - Finance Investments. The Company makes equity investments in entities that finance affordable housing and other community development projects and provide a return primarily through the realization of tax benefits. In most instances the investments require the funding of capital commitments in the future. While the Company's investment in an entity may exceed 50% of its outstanding equity interests, the entity is not consolidated as Webster is not involved in its management. For these investments, the Company determined it is not the primary beneficiary due to its inability to direct the activities that most significantly impact the economic performance of the VIEs. The Company applies the proportional amortization method to account for its investments in qualified affordable housing projects. At December 31, 2018 and December 31, 2017 , the aggregate carrying value of the Company's tax credit-finance investments was $29.1 million and $33.5 million , respectively, which represents the Company's maximum exposure to loss. At December 31, 2018 and December 31, 2017 , unfunded commitments have been recognized, totaling $10.4 million and $17.3 million , respectively, and are included in accrued expenses and other liabilities in the accompanying Consolidated Balance Sheets. Webster Statutory Trust. The Company owns all the outstanding common stock of Webster Statutory Trust, a financial vehicle that has issued, and in the future may issue, trust preferred securities. The trust is a VIE in which the Company is not the primary beneficiary. The trust's only assets are junior subordinated debentures issued by the Company, which were acquired by the trust using the proceeds from the issuance of the trust preferred securities and common stock. The junior subordinated debentures are included in long-term debt in the accompanying Consolidated Balance Sheets, and the related interest expense is reported as interest expense on long-term debt in the accompanying Consolidated Statements of Income. Other Investments. The Company invests in various alternative investments in which it holds a variable interest. These investments are non-public entities which cannot be redeemed since the Company’s investment is distributed as the underlying equity is liquidated. For these investments, the Company has determined it is not the primary beneficiary due to its inability to direct the activities that most significantly impact the economic performance of the VIEs. At December 31, 2018 and December 31, 2017 , the aggregate carrying value of the Company's other investments in VIEs was $17.6 million and $13.8 million , respectively, and the maximum exposure to loss of the Company's other investments in VIEs, including unfunded commitments, was $31.0 million and $22.9 million , respectively. Refer to Note 16: Fair Value Measurements for additional information.

Loans and Leases

Loans and Leases	12 Months Ended
	Dec. 31, 2018
Loans and Leases Receivable Disclosure [Abstract]
Loans and Leases	Loans and Leases The following table summarizes loans and leases: At December 31, (In thousands) 2018 2017 Residential $ 4,416,637 $ 4,490,878 Consumer 2,396,704 2,590,225 Commercial 6,216,606 5,368,694 Commercial Real Estate 4,927,145 4,523,828 Equipment Financing 508,397 550,233 Loans and leases (1) (2) $ 18,465,489 $ 17,523,858 (1) Loans and leases include net deferred fees and net premiums and discounts of $13.9 million and $20.6 million at December 31, 2018 and December 31, 2017 , respectively. (2) At December 31, 2018 , the Company had pledged $7.1 billion of eligible loans as collateral to support borrowing capacity at the FHLB of Boston and the FRB of Boston. Loans and Leases Portfolio Aging The following tables summarize the aging of loans and leases: At December 31, 2018 (In thousands) 30-59 Days Past Due and Accruing 60-89 Days 90 or More Days Past Due and Accruing Non-accrual Total Past Due and Non-accrual Current Total Loans and Leases Residential $ 8,513 $ 4,301 $ — $ 49,188 $ 62,002 $ 4,354,635 $ 4,416,637 Consumer: Home equity 9,250 5,385 — 33,495 48,130 2,121,049 2,169,179 Other consumer 1,774 957 — 1,494 4,225 223,300 227,525 Commercial: Commercial non-mortgage 1,011 702 104 55,810 57,627 5,189,808 5,247,435 Asset-based — — — 224 224 968,947 969,171 Commercial real estate: Commercial real estate 1,275 245 — 8,242 9,762 4,698,552 4,708,314 Commercial construction — — — — — 218,831 218,831 Equipment financing 510 405 — 6,314 7,229 501,168 508,397 Total $ 22,333 $ 11,995 $ 104 $ 154,767 $ 189,199 $ 18,276,290 $ 18,465,489 At December 31, 2017 (In thousands) 30-59 Days Past Due and Accruing 60-89 Days 90 or More Days Past Due and Accruing Non-accrual Total Past Due and Non-accrual Current Total Loans and Leases Residential $ 8,643 $ 5,146 $ — $ 44,481 $ 58,270 $ 4,432,608 $ 4,490,878 Consumer: Home equity 12,668 5,770 — 35,645 54,083 2,298,185 2,352,268 Other consumer 2,556 1,444 — 1,707 5,707 232,250 237,957 Commercial: Commercial non-mortgage 5,212 603 644 39,214 45,673 4,488,242 4,533,915 Asset-based — — — 589 589 834,190 834,779 Commercial real estate: Commercial real estate 478 77 248 4,484 5,287 4,238,987 4,244,274 Commercial construction — — — — — 279,554 279,554 Equipment financing 1,732 626 — 393 2,751 547,482 550,233 Total $ 31,289 $ 13,666 $ 892 $ 126,513 $ 172,360 $ 17,351,498 $ 17,523,858 Interest on non-accrual loans and leases that would have been recorded as additional interest income for the years ended December 31, 2018 , 2017 , and 2016 , had the loans and leases been current in accordance with their original terms, totaled $9.7 million , $8.4 million , and $11.0 million , respectively. Allowance for Loan and Lease Losses The following tables summarize the activity in, as well as the loan and lease balances that were evaluated for, the ALLL: At or for the Year ended December 31, 2018 (In thousands) Residential Consumer Commercial Commercial Real Estate Equipment Financing Total Allowance for loan and lease losses: Balance at January 1, 2018 $ 19,058 $ 36,190 $ 89,533 $ 49,407 $ 5,806 $ 199,994 Provision (benefit) charged to expense 2,016 4,628 23,041 12,644 (329 ) 42,000 Losses charged off (3,455 ) (19,228 ) (18,220 ) (2,061 ) (423 ) (43,387 ) Recoveries 1,980 7,091 4,439 161 75 13,746 Balance at December 31, 2018 $ 19,599 $ 28,681 $ 98,793 $ 60,151 $ 5,129 $ 212,353 Individually evaluated for impairment $ 4,286 $ 1,383 $ 7,824 $ 1,661 $ 196 $ 15,350 Collectively evaluated for impairment $ 15,313 $ 27,298 $ 90,969 $ 58,490 $ 4,933 $ 197,003 Loan and lease balances: Individually evaluated for impairment $ 103,531 $ 39,144 $ 99,512 $ 10,828 $ 6,315 $ 259,330 Collectively evaluated for impairment 4,313,106 2,357,560 6,117,094 4,916,317 502,082 18,206,159 Loans and leases $ 4,416,637 $ 2,396,704 $ 6,216,606 $ 4,927,145 $ 508,397 $ 18,465,489 At or for the Year ended December 31, 2017 (In thousands) Residential Consumer Commercial Commercial Real Estate Equipment Financing Total Allowance for loan and lease losses: Balance at January 1, 2017 $ 23,226 $ 45,233 $ 71,905 $ 47,477 $ 6,479 $ 194,320 Provision (benefit) charged to expense (2,692 ) 9,367 23,417 11,040 (232 ) 40,900 Losses charged off (2,500 ) (24,447 ) (8,147 ) (9,275 ) (558 ) (44,927 ) Recoveries 1,024 6,037 2,358 165 117 9,701 Balance at December 31, 2017 $ 19,058 $ 36,190 $ 89,533 $ 49,407 $ 5,806 $ 199,994 Individually evaluated for impairment $ 4,805 $ 1,668 $ 9,786 $ 272 $ 23 $ 16,554 Collectively evaluated for impairment $ 14,253 $ 34,522 $ 79,747 $ 49,135 $ 5,783 $ 183,440 Loan and lease balances: Individually evaluated for impairment $ 114,295 $ 45,436 $ 72,471 $ 11,226 $ 3,325 $ 246,753 Collectively evaluated for impairment 4,376,583 2,544,789 5,296,223 4,512,602 546,908 17,277,105 Loans and leases $ 4,490,878 $ 2,590,225 $ 5,368,694 $ 4,523,828 $ 550,233 $ 17,523,858 At or for the Year ended December 31, 2016 (In thousands) Residential Consumer Commercial Commercial Real Estate Equipment Financing Total Allowance for loan and lease losses: Balance at January 1, 2016 $ 25,876 $ 42,052 $ 59,977 $ 41,598 $ 5,487 $ 174,990 Provision (benefit) charged to expense 230 18,507 28,662 7,930 1,021 56,350 Losses charged off (4,636 ) (20,669 ) (18,360 ) (2,682 ) (565 ) (46,912 ) Recoveries 1,756 5,343 1,626 631 536 9,892 Balance at December 31, 2016 $ 23,226 $ 45,233 $ 71,905 $ 47,477 $ 6,479 $ 194,320 Individually evaluated for impairment $ 8,090 $ 2,903 $ 7,422 $ 169 $ 9 $ 18,593 Collectively evaluated for impairment $ 15,136 $ 42,330 $ 64,483 $ 47,308 $ 6,470 $ 175,727 Loan and lease balances: Individually evaluated for impairment $ 119,424 $ 45,719 $ 53,037 $ 24,755 $ 6,420 $ 249,355 Collectively evaluated for impairment 4,135,258 2,638,781 4,887,894 4,486,091 629,209 16,777,233 Loans and leases $ 4,254,682 $ 2,684,500 $ 4,940,931 $ 4,510,846 $ 635,629 $ 17,026,588 Impaired Loans and Leases The following tables summarize impaired loans and leases: At December 31, 2018 (In thousands) Unpaid Principal Balance Total Recorded Investment Recorded Investment No Allowance Recorded Investment With Allowance Related Valuation Allowance Residential: 1-4 family $ 113,575 $ 103,531 $ 64,899 $ 38,632 $ 4,286 Consumer home equity 44,654 39,144 30,576 8,568 1,383 Commercial: Commercial non-mortgage 120,165 99,287 65,724 33,563 7,818 Asset-based 550 225 — 225 6 Commercial real estate: Commercial real estate 13,355 10,828 2,125 8,703 1,661 Commercial construction — — — — — Equipment financing 6,368 6,315 2,946 3,369 196 Total $ 298,667 $ 259,330 $ 166,270 $ 93,060 $ 15,350 At December 31, 2017 (In thousands) Unpaid Principal Balance Total Recorded Investment Recorded Investment No Allowance Recorded Investment With Allowance Related Valuation Allowance Residential: 1-4 family $ 125,352 $ 114,295 $ 69,759 $ 44,536 $ 4,805 Consumer home equity 50,809 45,436 34,418 11,018 1,668 Commercial: Commercial non-mortgage 79,900 71,882 27,313 44,569 9,786 Asset based 3,272 589 589 — — Commercial real estate: Commercial real estate 11,994 11,226 6,387 4,839 272 Commercial construction — — — — — Equipment financing 3,409 3,325 2,932 393 23 Total $ 274,736 $ 246,753 $ 141,398 $ 105,355 $ 16,554 The following table summarizes the average recorded investment and interest income recognized for impaired loans and leases: Years ended December 31, 2018 2017 2016 (In thousands) Average Recorded Investment Accrued Interest Income Cash Basis Interest Income Average Recorded Investment Accrued Interest Income Cash Basis Interest Income Average Accrued Cash Basis Interest Income Residential $ 108,913 $ 3,781 $ 1,106 $ 116,859 $ 4,138 $ 1,264 $ 126,936 $ 4,377 $ 1,200 Consumer home equity 42,290 1,158 980 45,578 1,323 1,046 47,072 1,361 985 Commercial Commercial non-mortgage 85,585 3,064 — 62,459 1,095 — 54,708 1,540 — Asset based 407 — — 295 — — — — — Commercial real estate: Commercial real estate 11,027 198 — 17,397 417 — 28,451 511 — Commercial construction — — — 594 12 — 3,574 92 — Equipment financing 4,820 112 — 4,872 207 — 3,421 184 — Total $ 253,042 $ 8,313 $ 2,086 $ 248,054 $ 7,192 $ 2,310 $ 264,162 $ 8,065 $ 2,185 Credit Quality Indicators. To measure credit risk for the commercial, commercial real estate, and equipment financing portfolios, the Company employs a dual grade credit risk grading system for estimating the PD and the LGD. The credit risk grade system assigns a rating to each borrower and to the facility, which together form a Composite Credit Risk Profile. The credit risk grade system categorizes borrowers by common financial characteristics that measure the credit strength of borrowers and facilities by common structural characteristics. The Composite Credit Risk Profile has ten grades, with each grade corresponding to a progressively greater risk of loss. Grades (1) - (6) are considered pass ratings, and (7) - (10) are considered criticized as defined by the regulatory agencies. Risk ratings, assigned to differentiate risk within the portfolio, are reviewed on an ongoing basis and revised to reflect changes in a borrowers’ current financial position and outlook, risk profile, and the related collateral and structural position. Loan officers review updated financial information on at least an annual basis for all pass rated loans to assess the accuracy of the risk grade. Criticized loans undergo more frequent reviews and enhanced monitoring. A (7) "Special Mention" credit has the potential weakness that, if left uncorrected, may result in deterioration of the repayment prospects for the asset. An (8) "Substandard" asset has a well defined weakness that jeopardizes the full repayment of the debt. An asset rated (9) "Doubtful" has all of the same weaknesses as a substandard credit with the added characteristic that the weakness makes collection or liquidation in full, given current facts, conditions, and values, improbable. Assets classified as (10) "Loss" in accordance with regulatory guidelines are considered uncollectible and charged off. The following table summarizes commercial, commercial real estate and equipment financing loans and leases segregated by risk rating exposure: Commercial Commercial Real Estate Equipment Financing At December 31, At December 31, At December 31, (In thousands) 2018 2017 2018 2017 2018 2017 (1) - (6) Pass $ 5,781,138 $ 5,048,162 $ 4,773,298 $ 4,355,916 $ 494,585 $ 525,105 (7) Special Mention 206,351 104,594 75,338 62,065 1,303 8,022 (8) Substandard 222,405 206,883 78,509 105,847 12,509 17,106 (9) Doubtful 6,712 9,055 — — — — Total $ 6,216,606 $ 5,368,694 $ 4,927,145 $ 4,523,828 $ 508,397 $ 550,233 For residential and consumer loans, the Company considers factors such as past due status, updated FICO scores, employment status, collateral, geography, loans discharged in bankruptcy, and the status of first lien position loans on second lien position loans as credit quality indicators. On an ongoing basis for portfolio monitoring purposes, the Company estimates the current value of property secured as collateral for home equity and residential first mortgage lending products. The estimate is based on home price indices compiled by the S&P/Case-Shiller Home Price Indices. The real estate price data is applied to the loan portfolios taking into account the age of the most recent valuation and geographic area. Troubled Debt Restructurings The following table summarizes information for TDRs: At December 31, (Dollars in thousands) 2018 2017 Accrual status $ 138,479 $ 147,113 Non-accrual status 91,935 74,291 Total recorded investment of TDR $ 230,414 $ 221,404 Specific reserves for TDR included in the balance of ALLL $ 11,930 $ 12,384 Additional funds committed to borrowers in TDR status 3,893 2,736 For years ended December 31, 2018 , 2017 and 2016 , Webster charged off $14.3 million , $3.2 million , and $18.6 million , respectively, for the portion of TDRs deemed to be uncollectible. The following table provides information on the type of concession for loans and leases modified as TDRs: Years ended December 31, 2018 2017 2016 Number of Loans and Leases Post- Modification Recorded Investment (1) Number of Loans and Leases Post- Modification Recorded Investment (1) Number of Loans and Leases Post- Modification Recorded Investment (1) (Dollars in thousands) Residential: Extended Maturity 1 $ 20 16 $ 2,569 17 $ 2,801 Adjusted Interest rates — — 2 335 2 528 Combination Rate and Maturity 9 947 12 1,733 13 1,537 Other (2) 21 3,573 39 6,200 24 4,090 Consumer home equity: Extended Maturity 4 469 12 976 11 484 Adjusted Interest rates — — 1 247 — — Combination Rate and Maturity 6 618 14 3,469 15 1,156 Other (2) 45 2,812 73 4,907 52 3,131 Commercial non mortgage: Extended Maturity 12 823 12 1,233 12 14,883 Adjusted Interest rates — — — — — — Combination Rate and Maturity 15 8,842 18 9,592 2 648 Other (2) 20 41,248 4 6,375 13 1,767 Commercial real estate: Extended Maturity 2 97 — — 3 4,921 Adjusted Interest rates — — — — 1 237 Combination Rate and Maturity 3 1,485 — — 2 335 Other (2) 1 5,111 — — 1 509 Equipment Financing Extended Maturity 4 736 — — 7 6,642 Total 143 $ 66,781 203 $ 37,636 175 $ 43,669 (1) Post-modification balances approximate pre-modification balances. The aggregate amount of charge-offs as a result of the restructurings was not significant. (2) Other includes covenant modifications, forbearance, loans discharged under Chapter 7 bankruptcy, and/or other concessions. The were no significant amounts of loans and leases modified as TDRs within the previous 12 months and for which there was a payment default for the years ended December 31, 2018 , 2017 and 2016 . The recorded investment of TDRs in commercial, commercial real estate, and equipment financing segregated by risk rating exposure is as follows: At December 31, (In thousands) 2018 2017 (1) - (6) Pass $ 13,165 $ 8,268 (7) Special Mention 84 355 (8) Substandard 67,880 53,050 (9) Doubtful 6,610 — Total $ 87,739 $ 61,673

Transfers of Financial Assets

Transfers of Financial Assets	12 Months Ended
	Dec. 31, 2018
Transfers and Servicing [Abstract]
Transfers of Financial Assets	Transfers of Financial Assets Transfers of Financial Assets The Company sells financial assets in the normal course of business, primarily residential mortgage loans sold to government-sponsored enterprises through established programs and securitizations. Gains and losses from initial measurement and subsequent changes in fair value are recognized in earnings. The gain or loss on residential mortgage loans sold and the related origination fee income, as well as fair value adjustments to loans held-for-sale are included as mortgage banking activities in the accompanying Consolidated Statements of Income. The Company may be required to repurchase a loan in the event of certain breaches of the representations and warranties, or in the event of default of the borrower within 90 days of sale, as provided for in the sale agreements. A reserve for loan repurchases provides for estimated losses pertaining to the potential repurchase of loans associated with the Company's mortgage banking activities. The reserve reflects loan repurchase requests received by the Company for which management evaluates the identity of counterparty, the vintage of the loans sold, the amount of open repurchase requests, specific loss estimates for each open request, the current level of loan losses in similar vintages held in the residential loan portfolio, and estimated recoveries on the underlying collateral. The reserve also reflects management’s expectation of losses from loan repurchase requests for which the Company has not yet been notified, as the performance of loans sold and the quality of the servicing provided by the acquirer may also impact potential future requests. The provision recorded at the time of the loan sale is netted from the gain or loss recorded in mortgage banking activities, while any incremental provision, post loan sale, is recorded in other non-interest expense in the accompanying Consolidated Statements of Income. The following table provides a summary of activity in the reserve for loan repurchases: Years ended December 31, (In thousands) 2018 2017 2016 Beginning balance $ 872 $ 790 $ 1,192 (Benefit) provision charged to expense (160 ) 100 (303 ) Repurchased loans and settlements charged off (38 ) (18 ) (99 ) Ending balance $ 674 $ 872 $ 790 The following table provides information for mortgage banking activities: Years ended December 31, (In thousands) 2018 2017 2016 Residential mortgage loans held for sale: Proceeds from sale $ 188,025 $ 335,656 $ 438,925 Loans sold with servicing rights retained 166,909 304,788 399,318 Net gain on sale 3,146 6,211 11,629 Ancillary fees 1,544 2,629 3,532 Fair value option adjustment (266 ) 1,097 (526 ) The Company has retained servicing rights on residential mortgage loans totaling $2.5 billion and $2.6 billion at December 31, 2018 and 2017 , respectively. The following table presents the changes in carrying value for mortgage servicing assets: Years ended December 31, (In thousands) 2018 2017 2016 Beginning balance $ 25,139 $ 24,466 $ 20,698 Additions 4,459 9,249 11,312 Amortization (8,383 ) (8,576 ) (7,544 ) Ending balance $ 21,215 $ 25,139 $ 24,466 Loan servicing fees, net of mortgage servicing rights amortization, were $1.2 million , $0.8 million , and $1.1 million , for the years ended December 31, 2018 , 2017 , and 2016 , respectively, and are included as a component of loan and lease related fees in the accompanying Consolidated Statements of Income. See Note 16: Fair Value Measurements for additional fair value information on loans held for sale and mortgage servicing assets. Additionally, loans not originated for sale were sold approximately at carrying value, except as noted, for cash proceeds of $1.3 million for certain commercial loans and $0.4 million for certain residential loans for the year ended December 31, 2018 ; for cash proceeds of $7.2 million for certain commercial loans and $7.4 million for certain residential loans for the year ended December 31, 2017 ; and for cash proceeds of $26.5 million , resulting in a gain of $2.1 million , for certain commercial loans and $7.6 for certain residential loans for the year ended December 31, 2016

Premises and Equipment

Premises and Equipment	12 Months Ended
	Dec. 31, 2018
Property, Plant and Equipment [Abstract]
Premises and Equipment	Premises and Equipment A summary of premises and equipment follows: At December 31, (In thousands) 2018 2017 Land $ 10,997 $ 11,302 Buildings and improvements 79,619 80,646 Leasehold improvements 77,669 82,067 Fixtures and equipment 75,219 76,665 Data processing and software 252,723 234,667 Total premises and equipment 496,227 485,347 Less: Accumulated depreciation and amortization (371,377 ) (355,346 ) Premises and equipment, net $ 124,850 $ 130,001 Depreciation and amortization of premises and equipment was $34.9 million , $33.1 million , and $30.8 million for the years ended December 31, 2018 , 2017 , and 2016 , respectively. The following table provides a summary of activity for assets held for disposition: Years ended December 31, (In thousands) 2018 2017 Beginning balance $ 144 $ 637 Additions 498 2,006 Write-downs (137 ) (529 ) Sales (414 ) (1,970 ) Ending balance $ 91 $ 144

Goodwill and Other Intangible A

Goodwill and Other Intangible Assets	12 Months Ended
	Dec. 31, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Other Intangible Assets	Goodwill and Other Intangible Assets Goodwill and other intangible assets by reportable segment consisted of the following: At December 31, 2018 2017 (In thousands) Gross Carrying Amount Accumulated Amortization Net Carrying Amount Gross Carrying Amount Accumulated Amortization Net Carrying Amount Goodwill: Community Banking $ 516,560 $ 516,560 HSA Bank 21,813 21,813 Total Goodwill $ 538,373 $ 538,373 Other intangible assets: HSA Bank - Core deposits $ 22,000 $ (10,842 ) $ 11,158 $ 22,000 $ (8,610 ) $ 13,390 HSA Bank - Customer relationships 21,000 (6,394 ) 14,606 21,000 (4,779 ) 16,221 Total Other intangible assets $ 43,000 $ (17,236 ) $ 25,764 $ 43,000 $ (13,389 ) $ 29,611 As of December 31, 2018 , the remaining estimated aggregate future amortization expense for intangible assets is as follows: (In thousands) 2019 $ 3,847 2020 3,847 2021 3,847 2022 3,847 2023 3,847 Thereafter 6,529

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes Income tax expense reflects the following expense (benefit) components: Years ended December 31, (In thousands) 2018 2017 2016 Current: Federal $ 58,334 $ 96,364 $ 73,194 State and local 13,409 11,061 5,429 Total current 71,743 107,425 78,623 Deferred: Federal 8,508 39,568 12,542 State and local 964 (48,642 ) 5,158 Total deferred 9,472 (9,074 ) 17,700 Total federal 66,842 135,932 85,736 Total state and local 14,373 (37,581 ) 10,587 Income tax expense $ 81,215 $ 98,351 $ 96,323 Included in the Company's income tax expense for the years ended December 31, 2018 , 2017 , and 2016 , are net tax credits of $1.2 million , $1.6 million , and $1.0 million , respectively. The income tax expense for the year ended December 31, 2017 also included benefits from operating loss carryforwards of $25.1 million . These net tax credits and benefits are exclusive of the Tax Act impacts. The Company's deferred state and local benefit in 2017 includes $47.5 million related to a reduction in its beginning-of-year valuation allowance for SALT DTA's, or $37.5 million net of deferred federal expense of $10.0 million . The deferred state and local benefit in 2017 also includes $1.8 million from other SALT DTA adjustments, net of federal effects. The Company's deferred federal expense in 2017 also includes $31.5 million from a re-measurement of its DTA upon the enactment of the Tax Act. Due to a $10.6 million impact of the Tax Act on the $39.3 million of net SALT DTA adjustments noted above, the Company reported a $20.9 million expense attributable to the Tax Act, and a $28.7 million net benefit from SALT DTAs in 2017. The following table reflects a reconciliation of reported income tax expense to the amount that would result from applying the federal statutory rate of 21.0% in 2018 , and 35.0% in 2017 and 2016 : Years ended December 31, 2018 2017 2016 (Dollars in thousands) Amount Percent Amount Percent Amount Percent Income tax expense at federal statutory rate $ 92,743 21.0 % $ 123,826 35.0 % $ 106,208 35.0 % Reconciliation to reported income tax expense: SALT expense, net of federal 11,354 2.6 8,189 2.3 6,882 2.3 Tax-exempt interest income, net (6,475 ) (1.5 ) (10,826 ) (3.1 ) (8,917 ) (2.9 ) Increase in cash surrender value of life insurance (3,069 ) (0.7 ) (5,120 ) (1.4 ) (5,166 ) (1.7 ) Excess tax benefits, net (4,483 ) (1.0 ) (6,349 ) (1.8 ) — — Non-deductible FDIC deposit insurance premiums 2,215 0.5 — — — — SALT DTA adjustments, net of federal — — (28,724 ) (8.1 ) — — Tax Act impacts, net (10,982 ) (2.5 ) 20,891 5.9 — — Other, net (88 ) — (3,536 ) (1.0 ) (2,684 ) (1.0 ) Income tax expense and effective tax rate $ 81,215 18.4 % $ 98,351 27.8 % $ 96,323 31.7 % Included in the Tax Act impacts, net for 2018 are $10.4 million of tax planning benefits related to the Tax Act. The following table reflects the significant components of the DTAs, net: At December 31, (In thousands) 2018 2017 Deferred tax assets: Allowance for loan and lease losses $ 54,390 $ 51,203 Net operating loss and credit carry forwards 70,808 71,813 Compensation and employee benefit plans 29,623 25,023 Net unrealized loss on securities available for sale 25,060 9,548 Other 14,388 15,529 Gross deferred tax assets 194,269 173,116 Valuation allowance (38,181 ) (38,292 ) Total deferred tax assets, net of valuation allowance $ 156,088 $ 134,824 Deferred tax liabilities: Equipment financing leases $ 28,140 $ 27,955 Premises and equipment 10,293 472 Loan origination costs, net 9,608 1,018 Goodwill and other intangible assets 6,293 6,364 Mortgage servicing assets 3,604 4,445 Other 1,634 1,940 Gross deferred tax liabilities 59,572 42,194 Deferred tax assets, net $ 96,516 $ 92,630 The Company's DTAs, net increased by $3.9 million during 2018 , reflecting the $9.5 million deferred tax expense and a $13.4 million benefit allocated directly to shareholders' equity. The $38.2 million valuation allowance at December 31, 2018 is attributable to SALT net operating loss carryforwards and the $111 thousand decrease in the valuation allowance during 2018 pertains to the utilization of $0.4 million of capital loss carryforwards previously expected to expire. SALT net operating loss carryforwards approximating $1.2 billion at December 31, 2018 are scheduled to expire in varying amounts during tax years 2023 through 2037, and credits totaling $0.5 million at December 31, 2018 , have a five-year carryover period, with excess credits subject to expiration annually. The valuation allowance of $38.2 million has been established for approximately $644 million of those net operating loss carryforwards estimated to expire. Management believes it is more likely than not that the results of future operations will generate sufficient taxable income to realize its total DTAs, net of the valuation allowance. Although taxable income in prior years is no longer able to be included as a source of taxable income, due to the general repeal of the carryback of net operating losses under the Tax Act, significant positive evidence remains in support of management's conclusion regarding the realizability of Webster's DTAs, including projected future reversals of existing taxable temporary differences and book-taxable income levels in recent and projected future years. There can, however, be no assurance that any specific level of future income will be generated or that the Company’s DTAs will ultimately be realized. A deferred tax liability of $15.2 million has not been recognized for certain thrift bad-debt reserves, established before 1988, that would become taxable upon the occurrence of certain events: distributions by Webster Bank in excess of certain earnings and profits; the redemption of Webster Bank’s stock; or liquidation. Webster does not expect any of those events to occur. At December 31, 2018 the cumulative taxable temporary differences applicable to those reserves approximated $58.0 million . The following table reflects a reconciliation of the beginning and ending balances of unrecognized tax benefits (UTBs): Years ended December 31, (In thousands) 2018 2017 2016 Beginning balance $ 3,595 $ 3,847 $ 5,094 Additions as a result of tax positions taken during the current year 249 584 613 Additions as a result of tax positions taken during prior years 71 7 — Reductions as a result of tax positions taken during prior years (474 ) (61 ) (625 ) Reductions relating to settlements with taxing authorities (97 ) (392 ) (693 ) Reductions as a result of lapse of statute of limitation periods (488 ) (390 ) (542 ) Ending balance $ 2,856 $ 3,595 $ 3,847 At December 31, 2018 , 2017 , and 2016 , there were $2.3 million , $2.8 million , and $2.5 million , respectively, of UTBs that if recognized would affect the effective tax rate. Webster recognizes interest and penalties related to UTBs, where applicable, in income tax expense. During the years ended December 31, 2018 , 2017 , and 2016 , Webster recognized none , an expense of $0.2 million , and a benefit of $0.2 million , respectively. At December 31, 2018 and 2017 , the Company had accrued interest and penalties related to UTBs of $1.8 million and $1.9 million , respectively. Webster has determined it is reasonably possible that its total UTBs could decrease by an amount in the range of $0.7 million to $1.8 million by the end of 2019, primarily as a result of potential lapses in statute-of-limitation periods and/or potential settlements with state and local taxing authorities concerning apportionment and tax-base determinations.

Deposits

Deposits	12 Months Ended
	Dec. 31, 2018
Banking and Thrift [Abstract]
Deposits	Deposits A summary of deposits by type follows: At December 31, (In thousands) 2018 2017 Non-interest-bearing: Demand $ 4,162,446 $ 4,191,496 Interest-bearing: Checking 2,518,472 2,736,952 Health savings accounts 5,740,601 5,038,681 Money market 2,100,084 2,209,492 Savings 4,140,696 4,348,700 Time deposits 3,196,546 2,468,408 Total interest-bearing 17,696,399 16,802,233 Total deposits $ 21,858,845 $ 20,993,729 Time deposits and interest-bearing checking, included in above balances, obtained through brokers $ 869,003 $ 898,157 Time deposits, included in above balance, that exceed the FDIC limit 555,949 561,512 Demand deposit overdrafts reclassified as loan balances 2,245 2,210 The scheduled maturities of time deposits are as follows: (In thousands) At December 31, 2018 2019 $ 2,381,229 2020 594,754 2021 143,324 2022 47,224 2023 30,015 Thereafter — Total time deposits $ 3,196,546

Borrowings

Borrowings	12 Months Ended
	Dec. 31, 2018
Debt Disclosure [Abstract]
Borrowings	Borrowings Total borrowings of $2.6 billion at December 31, 2018 and $2.5 billion at December 31, 2017 , are described in detail below. The following table summarizes securities sold under agreements to repurchase and other borrowings: At December 31, (In thousands) 2018 2017 Total Outstanding Rate Total Outstanding Rate Securities sold under agreements to repurchase: Original maturity of one year or less $ 236,874 0.35 % $ 288,269 0.17 % Original maturity of greater than one year, non-callable — — 300,000 3.10 Total securities sold under agreements to repurchase 236,874 0.35 588,269 1.66 Fed funds purchased 345,000 2.52 55,000 1.37 Securities sold under agreements to repurchase and other borrowings $ 581,874 1.64 $ 643,269 1.64 Repurchase agreements are used as a source of borrowed funds and are collateralized by U.S. Government agency mortgage-backed securities which are delivered to broker/dealers. Repurchase agreements counterparties are limited to primary dealers in government securities and commercial/municipal customers through Webster’s Treasury Unit. Dealer counterparties have the right to pledge, transfer, or hypothecate purchased securities during the term of the transaction. The Company has right of offset with respect to all repurchase agreement assets and liabilities. Total securities sold under agreements to repurchase represents the gross amount for these transactions, as only liabilities are outstanding for the periods presented. The following table provides information for FHLB advances: At December 31, 2018 2017 (Dollars in thousands) Total Outstanding Weighted- Average Contractual Coupon Rate Total Outstanding Weighted- Average Contractual Coupon Rate Maturing within 1 year $ 1,403,026 2.55 % $ 1,150,000 1.48 % After 1 but within 2 years 215,000 1.73 103,026 1.81 After 2 but within 3 years 200,000 3.16 215,000 1.73 After 3 but within 4 years 150 — 200,000 2.06 (1) After 4 but within 5 years 242 2.95 170 — After 5 years 8,390 2.65 8,909 2.65 (1) Federal Home Loan Bank advances $ 1,826,808 2.52 $ 1,677,105 1.61 (1) Aggregate carrying value of assets pledged as collateral $ 6,689,761 $ 6,402,066 Remaining borrowing capacity 2,568,664 2,600,624 (1) Weighted-average contractual coupon rates for December 31, 2017 are presented as revised for these classifications to correct an immaterial error in presentation. The percentages reported in the Company's 2017 Annual Report on Form 10-K were: After 3 but within 4 years - 4.13% ; After 5 years - 1.96% ; and overall rate - 1.85% . Webster Bank was in compliance with FHLB collateral requirements for the periods presented. Eligible collateral, primarily certain residential and commercial real estate loans, has been pledged to secure FHLB advances. The following table summarizes long-term debt: At December 31, (Dollars in thousands) 2018 2017 4.375% Senior fixed-rate notes due February 15, 2024 $ 150,000 $ 150,000 Junior subordinated debt Webster Statutory Trust I floating-rate notes due September 17, 2033 (1) 77,320 77,320 Total notes and subordinated debt 227,320 227,320 Discount on senior fixed-rate notes (608 ) (727 ) Debt issuance cost on senior fixed-rate notes (691 ) (826 ) Long-term debt $ 226,021 $ 225,767 (1) The interest rate on Webster Statutory Trust I floating-rate notes, which varies quarterly based on 3-month LIBOR plus 2.95% , was 5.74% at December 31, 2018 and 4.55% at December 31, 2017

Shareholders' Equity

Shareholders' Equity	12 Months Ended
	Dec. 31, 2018
Equity [Abstract]
Shareholders' Equity	Shareholders' Equity Share activity during the year ended December 31, 2018 is as follows: Preferred Stock Series F Common Stock Issued Treasury Stock Held Common Stock Outstanding Balance at January 1, 2018 6,000 93,680,291 1,658,526 92,021,765 Restricted share activity — — (182,553 ) 182,553 Stock options exercised — — (182,517 ) 182,517 Common stock repurchased — — 215,000 (215,000 ) Warrant exercise — 6,020 — 6,020 Series F Preferred Stock issuance — — — — Series E Preferred Stock redemption — — — — Balance at December 31, 2018 6,000 93,686,311 1,508,456 92,177,855 Common Stock On October 24, 2017, Webster announced that its Board of Directors had authorized a $100 million common stock repurchase program under which shares may be repurchased from time to time in the open market or in privately negotiated transactions, subject to market conditions and other factors. During 2018 , common stock repurchased was acquired, at an average cost of $56.55 per common share. The shares were acquired under authority of a remaining balance from a previous program coupled with the current program, which results in a remaining repurchase authority for the common stock repurchase program of $91.7 million at December 31, 2018 . On June 8, 2011, the U.S. Treasury closed an underwritten public offering of 3,282,276 warrants issued in connection with the Company’s participation in the Capital Purchase Program, each representing the right to purchase one share of Webster common stock, $0.01 par value per share. As of December 31, 2017 , 8,752 warrants remained outstanding. During 2018 , there were 8,647 warrants exercised in cashless exchange transactions. The warrants had an exercise price of $18.28 and expired on November 21, 2018. Accordingly, no warrants remained outstanding at December 31, 2018 . Preferred Stock Webster has 6,000,000 depository shares outstanding, each representing 1/1000th ownership interest in a share of Webster's 5.25% Series F Non-Cumulative Perpetual Preferred Stock, par value $0.01 per share, with a liquidation preference of $25,000 per share (equivalent to $25 per depository share) (the Series F Preferred Stock). Webster will pay dividends as declared by the Board of Directors or a duly authorized committee of the Board. Dividends are payable at a rate of 5.25% per annum, quarterly in arrears, on the fifteenth day of each March, June, September, and December. Dividends on the Series F Preferred Stock are not cumulative and are not mandatory. If for any reason the Board of Directors or a duly authorized committee of the Board does not declare a dividend on the Series F Preferred Stock for any dividend period, such dividend will not accrue or be payable, and Webster will have no obligation to pay dividends for such dividend period, whether or not dividends are declared for any future dividend periods. The terms of the Series F Preferred Stock prohibit the Company from declaring or paying any cash dividends on its common stock, unless Webster has declared and paid full dividends on the Series F Preferred Stock for the most recently completed dividend period.

Accumulated Other Comprehensive

Accumulated Other Comprehensive Loss, Net of Tax	12 Months Ended
	Dec. 31, 2018
Equity [Abstract]
Accumulated Other Comprehensive Loss, Net of Tax	Accumulated Other Comprehensive Loss, Net of Tax The following table summarizes the changes in AOCL by component: (In thousands) Available For Sale Securities Derivative Instruments Defined Benefit Pension and Other Postretirement Benefit Plans Total Balance at December 31, 2015 $ (6,407 ) $ (22,980 ) $ (48,719 ) $ (78,106 ) Other comprehensive (loss) income before reclassifications (8,901 ) 825 (232 ) (8,308 ) Amounts reclassified from accumulated other comprehensive loss (168 ) 5,087 4,502 9,421 Net current-period other comprehensive (loss) income, net of tax (9,069 ) 5,912 4,270 1,113 Balance at December 31, 2016 (15,476 ) (17,068 ) (44,449 ) (76,993 ) Other comprehensive (loss) income before reclassifications (7,590 ) 181 98 (7,311 ) Amounts reclassified from accumulated other comprehensive loss — 4,384 4,037 8,421 Net current-period other comprehensive (loss) income, net of tax (7,590 ) 4,565 4,135 1,110 Balance at Adoption of ASU No. 2018-02, Income Statement - Reporting Comprehensive Income (Topic 220) - Reclassification of Certain Tax Effects from AOCI (4,881 ) (2,513 ) (8,254 ) (15,648 ) Balance at December 31, 2017 (27,947 ) (15,016 ) (48,568 ) (91,531 ) Other comprehensive (loss) income before reclassifications (43,427 ) 208 (7,122 ) (50,341 ) Amounts reclassified from accumulated other comprehensive loss — 5,495 5,725 11,220 Net current-period other comprehensive (loss) income, net of tax (43,427 ) 5,703 (1,397 ) (39,121 ) Balance at December 31, 2018 $ (71,374 ) $ (9,313 ) $ (49,965 ) $ (130,652 ) The following table provides information for the items reclassified from AOCL: Years ended December 31, Accumulated Other Comprehensive Loss Components 2018 2017 2016 Associated Line Item in the Consolidated Statements Of Income (In thousands) Available-for-sale securities: Unrealized gains on investments $ — $ — $ 414 Gain on sale of investment securities, net Unrealized losses on investments — — (149 ) Impairment loss recognized in earnings Total before tax — — 265 Tax expense — — (97 ) Income tax expense Net of tax $ — $ — $ 168 Derivative instruments: Cash flow hedges $ (7,425 ) $ (7,160 ) $ (8,020 ) Interest expense Tax benefit 1,930 2,776 2,933 Income tax expense Net of tax $ (5,495 ) $ (4,384 ) $ (5,087 ) Defined benefit pension and other postretirement benefit plans: Amortization of net loss $ (7,708 ) $ (6,612 ) $ (7,126 ) (1) Prior service costs — — (14 ) (1) Total before tax (7,708 ) (6,612 ) (7,140 ) Tax benefit 1,983 2,575 2,638 Income tax expense Net of tax $ (5,725 ) $ (4,037 ) $ (4,502 ) (1) These accumulated other comprehensive income components are included in the computation of net periodic benefit cost (see Note 17: Retirement Benefit Plans for further details). The following tables summarize the items and related tax effects for each component of OCI/OCL, net of tax: Year ended December 31, 2018 (In thousands) Pre-Tax Amount Tax Benefit (Expense) Net of Tax Amount Available-for-sale securities: Net unrealized loss during the period $ (58,792 ) $ 15,365 $ (43,427 ) Reclassification for net gain included in net income — — — Net non-credit other-than-temporary impairment — — — Total available-for-sale securities (58,792 ) 15,365 (43,427 ) Derivative instruments: Net unrealized gain during the period 280 (72 ) 208 Reclassification adjustment for net loss included in net income 7,425 (1,930 ) 5,495 Total derivative instruments 7,705 (2,002 ) 5,703 Defined benefit pension and other postretirement benefit plans: Current year actuarial loss (9,600 ) 2,478 (7,122 ) Reclassification adjustment for amortization of net loss included in net income 7,708 (1,983 ) 5,725 Reclassification adjustment for prior service cost included in net income — — — Total defined benefit pension and postretirement benefit plans (1,892 ) 495 (1,397 ) Other comprehensive loss, net of tax $ (52,979 ) $ 13,858 $ (39,121 ) Year ended December 31, 2017 (In thousands) Pre-Tax Amount Tax Benefit (Expense) Net of Tax Amount Available-for-sale securities: Net unrealized loss during the period $ (12,423 ) $ 4,833 $ (7,590 ) Reclassification for net gain included in net income — — — Net non-credit other-than-temporary impairment — — — Total available-for-sale securities (12,423 ) 4,833 (7,590 ) Derivative instruments: Net unrealized gain during the period 291 (110 ) 181 Reclassification adjustment for net loss included in net income 7,160 (2,776 ) 4,384 Total derivative instruments 7,451 (2,886 ) 4,565 Defined benefit pension and other postretirement benefit plans: Current year actuarial gain 155 (57 ) 98 Reclassification adjustment for amortization of net loss included in net income 6,612 (2,575 ) 4,037 Reclassification adjustment for prior service cost included in net income — — — Total defined benefit pension and postretirement benefit plans 6,767 (2,632 ) 4,135 Other comprehensive income, net of tax $ 1,795 $ (685 ) $ 1,110 Year ended December 31, 2016 (In thousands) Pre-Tax Amount Tax Benefit (Expense) Net of Tax Amount Available-for-sale securities: Net unrealized loss during the period $ (14,113 ) $ 5,212 $ (8,901 ) Reclassification for net gain included in net income (414 ) 152 (262 ) Net non-credit other-than-temporary impairment 149 (55 ) 94 Total available-for-sale securities (14,378 ) 5,309 (9,069 ) Derivative instruments: Net unrealized gain during the period 1,331 (506 ) 825 Reclassification adjustment for net loss included in net income 8,020 (2,933 ) 5,087 Total derivative instruments 9,351 (3,439 ) 5,912 Defined benefit pension and other postretirement benefit plans: Current year actuarial loss (368 ) 136 (232 ) Reclassification adjustment for amortization of net loss included in net income 7,126 (2,633 ) 4,493 Reclassification adjustment for prior service cost included in net income 14 (5 ) 9 Total defined benefit pension and postretirement benefit plans 6,772 (2,502 ) 4,270 Other comprehensive income, net of tax $ 1,745 $ (632 ) $ 1,113

Regulatory Matters

Regulatory Matters	12 Months Ended
	Dec. 31, 2018
Regulatory Capital Requirements [Abstract]
Regulatory Matters	Regulatory Matters Capital Requirements Webster Financial Corporation is subject to regulatory capital requirements administered by the Federal Reserve System, while Webster Bank is subject to regulatory capital requirements administered by the OCC. Regulatory authorities can initiate certain mandatory actions if Webster Financial Corporation or Webster Bank fail to meet minimum capital requirements, which could have a direct material effect on the Company's financial statements. Under capital adequacy guidelines and the regulatory framework for prompt corrective action, both Webster Financial Corporation and Webster Bank must meet specific capital guidelines that involve quantitative measures of assets, liabilities, and certain off-balance sheet items calculated under regulatory accounting practices. These quantitative measures require minimum amounts and ratios to ensure capital adequacy. Under Basel III, total risk-based capital is comprised of three categories: CET1 capital, additional Tier 1 capital, and Tier 2 capital. CET1 capital includes common shareholders' equity, less deductions for goodwill and other intangibles adjusted for certain deferred tax liabilities. Webster's common shareholders' equity, for purposes of CET1 capital, excludes AOCL components as permitted by the opt-out election taken by Webster upon adoption of Basel III. Tier 1 capital is comprised of CET1 capital plus perpetual preferred stock, while Tier 2 capital includes qualifying subordinated debt and qualifying allowance for credit losses, that together equal total capital. The following table provides information on the capital ratios for Webster Financial Corporation and Webster Bank: Actual Capital Requirements Adequately Capitalized Well Capitalized (Dollars in thousands) Amount Ratio Amount Ratio Amount Ratio At December 31, 2018 Webster Financial Corporation CET1 risk-based capital $ 2,284,978 11.44 % $ 898,972 4.5 % $ 1,298,514 6.5 % Total risk-based capital 2,722,194 13.63 1,598,172 8.0 1,997,715 10.0 Tier 1 risk-based capital 2,430,015 12.16 1,198,629 6.0 1,598,172 8.0 Tier 1 leverage capital 2,430,015 9.02 1,077,303 4.0 1,346,628 5.0 Webster Bank CET1 risk-based capital $ 2,170,566 10.87 % $ 898,317 4.5 % $ 1,297,569 6.5 % Total risk-based capital 2,385,425 11.95 1,597,008 8.0 1,996,260 10.0 Tier 1 risk-based capital 2,170,566 10.87 1,197,756 6.0 1,597,008 8.0 Tier 1 leverage capital 2,170,566 8.06 1,076,712 4.0 1,345,889 5.0 At December 31, 2017 Webster Financial Corporation CET1 risk-based capital $ 2,093,116 11.14 % $ 845,389 4.5 % $ 1,221,118 6.5 % Total risk-based capital 2,517,848 13.40 1,502,914 8.0 1,878,643 10.0 Tier 1 risk-based capital 2,238,172 11.91 1,127,186 6.0 1,502,914 8.0 Tier 1 leverage capital 2,238,172 8.63 1,036,817 4.0 1,296,021 5.0 Webster Bank CET1 risk-based capital $ 2,114,224 11.26 % $ 844,693 4.5 % $ 1,220,113 6.5 % Total risk-based capital 2,316,580 12.34 1,501,677 8.0 1,877,097 10.0 Tier 1 risk-based capital 2,114,224 11.26 1,126,258 6.0 1,501,677 8.0 Tier 1 leverage capital 2,114,224 8.14 1,038,442 4.0 1,298,052 5.0 Dividend Restrictions Webster Financial Corporation is dependent upon dividends from Webster Bank to provide funds for its cash requirements, including payments of dividends to shareholders. Banking regulations may limit the amount of dividends that may be paid. Approval by regulatory authorities is required if the effect of dividends declared would cause the regulatory capital of Webster Bank to fall below specified minimum levels, or if dividends declared exceed the net income for that year combined with the undistributed net income for the preceding two years. Dividends paid by Webster Bank to Webster Financial Corporation totaled $290 million and $120 million during the years ended December 31, 2018 and 2017 , respectively. Cash Restrictions Webster Bank is required by Federal Reserve System regulations to hold cash reserve balances, on hand or with Federal Reserve Banks. Pursuant to this requirement, the Bank held $81.2 million and $82.3 million at December 31, 2018 and 2017

Earnings Per Common Share

Earnings Per Common Share	12 Months Ended
	Dec. 31, 2018
Earnings Per Share [Abstract]
Earnings Per Common Share	Earnings Per Common Share Reconciliation of the calculation of basic and diluted earnings per common share follows: Years ended December 31, (In thousands, except per share data) 2018 2017 2016 Earnings for basic and diluted earnings per common share: Net income $ 360,418 $ 255,439 $ 207,127 Less: Preferred stock dividends 7,853 8,184 8,096 Net income available to common shareholders 352,565 247,255 199,031 Less: Earnings applicable to participating securities 862 424 608 Earnings applicable to common shareholders $ 351,703 $ 246,831 $ 198,423 Shares: Weighted-average common shares outstanding - basic 91,930 91,965 91,367 Effect of dilutive securities: Stock options and restricted stock 292 385 461 Warrants 5 6 28 Weighted-average common shares outstanding - diluted 92,227 92,356 91,856 Earnings per common share: Basic $ 3.83 $ 2.68 $ 2.17 Diluted 3.81 2.67 2.16 Potential common shares excluded from the effect of dilutive securities because they would have been anti-dilutive, are as follows: Years ended December 31, (In thousands) 2018 2017 2016 Stock options (shares with exercise price greater than market price) — — 41 Restricted stock (due to performance conditions on non-participating shares) 47 58 125 Refer to Note 11: Shareholders' Equity and Note 18: Share-Based Plans

Derivative Financial Instrument

Derivative Financial Instruments	12 Months Ended
	Dec. 31, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Financial Instruments	Derivative Financial Instruments Risk Management Objective of Using Derivatives Webster manages economic risks, including interest rate, liquidity, and credit risk by managing the amount, sources, and duration of its debt funding in conjunction with the use of interest rate derivative financial instruments. Webster enters into interest rate derivatives to mitigate the exposure related to business activities that result in the receipt or payment of, both future known and uncertain, cash amounts that are impacted by interest rates. The primary objective for using interest rate derivatives is to add stability to interest expense by managing exposure to interest rate movements. To accomplish this objective, Webster uses interest rate swaps and interest rate caps as part of its interest rate risk management strategy. Interest rate swaps and interest rate caps designated as cash flow hedges are designed to manage the risk associated with a forecasted event or an uncertain variable-rate cash flow. Forward-settle interest rate swaps protect the Company against adverse fluctuations in interest rates by reducing its exposure to variability in cash flows relating to interest payments on forecasted debt issuances. Interest rate swaps designated as cash flow hedges involve the receipt of variable amounts from a counterparty in exchange for the Company making fixed-rate payments over the life of the agreements without exchange of the underlying notional amount. Interest rate caps designated as cash flow hedges involve the receipt of variable amounts from a counterparty if interest rates rise above the strike rate on the contract in exchange for payment of an up-front premium. Cash flow hedges are used to regulate the variable cash flows associated with existing variable-rate debt and forecasted issuances of debt. Derivative instruments designated as cash flow hedges are recorded on the balance sheet at fair value. The effective portion of the change in the fair value of derivatives which are designated as cash flow hedges, and that qualify for hedge accounting, is recorded to AOCL and is reclassified into earnings in the subsequent periods that the hedged forecasted transaction affects earnings. The ineffective portion of the change in fair value of these derivatives, attributable to the difference in the effective date of the hedge and the effective date of the debt issuance, is recognized directly in earnings. During the periods presented, there was no ineffectiveness to be recognized in earnings. Certain fixed-rate obligations can be exposed to a change in fair value attributable to changes in benchmark interest rates. On occasion, interest rate swaps will be used to manage this exposure. An interest rate swap which involves the receipt of fixed-rate amounts from a counterparty in exchange for Webster making variable-rate payments over the life of the agreement, without the exchange of the underlying notional amount, is designated as a fair value hedge. For a qualifying derivative designated as a fair value hedge, the gain or loss on the derivative, as well as the gain or loss on the hedged item, is recognized in interest expense. During the periods presented, Webster did not have interest rate derivative financial instruments designated as fair value hedges and as a result, there was no impact to interest expense. Additionally, in order to address certain other risk management matters, the Company also utilizes derivative instruments that do not qualify for hedge accounting. These derivative instruments, which are recorded on the balance sheet at fair value, with changes in fair value recognized each period as other non-interest income in the accompanying Consolidated Statements of Income, are described in the following paragraphs. Interest rate swap and cap contracts are sold to commercial and other customers who wish to modify loan interest rate sensitivity. These contracts are offset with dealer counterparty transactions structured with matching terms. As a result, there is minimal impact on earnings, except for fee income earned in such transactions. All contracts eligible for clearing are cleared through CME. In accordance with its amended rulebook, CME legally characterizes variation margin payments made to and received from CME as settlement of derivatives rather than as collateral against derivatives. Risk participation agreements are entered into as financial guarantees of performance on interest rate swap derivatives. The purchased (asset) or sold (liability) guarantee allows the Company to participate-in (fee received) or participate-out (fee paid) the risk associated with certain derivative positions executed with the borrower by the lead bank in a loan syndication. Other derivatives include foreign currency forward contracts related to lending arrangements and customer hedging activity, a VISA equity swap transaction, and mortgage banking derivatives such as mortgage-backed securities related to residential loan commitments and loans held for sale. Mortgage banking derivatives are utilized by Webster in its efforts to manage risk of loss associated with its mortgage loan commitments and mortgage loans held for sale. Prior to closing and funding certain single-family residential mortgage loans interest rate lock commitments are generally extended to the borrowers. During the period from commitment date to closing date, Webster is subject to the risk that market rates of interest may change. If market rates rise, investors generally will pay less to purchase such loans causing a reduction in the anticipated gain on sale of the loans and possibly resulting in a loss. In an effort to mitigate such risk, forward delivery sales commitments are established under which Webster agrees to deliver whole mortgage loans to various investors or issue mortgage-backed securities. Mandatory forward commitments establish the price to be received upon the sale of the related mortgage loan, thereby mitigating certain interest rate risk. There is, however, still certain execution risk specifically related to Webster’s ability to close and deliver to its investors the mortgage loans it has committed to sell. Balance Sheet Impact of Derivative Instruments The following table presents the notional amounts and fair values of derivative positions: At December 31, 2018 At December 31, 2017 Asset Derivatives Liability Derivatives Asset Derivatives Liability Derivatives (In thousands) Notional Fair Notional Fair Notional Fair Notional Fair Designated as cash flow hedging instruments: Positions subject to a master netting agreement (1) Interest rate derivatives (2) $ 325,000 $ 3,050 $ — $ — $ 325,000 $ 2,770 $ — $ — Not designated as hedging instruments: Positions subject to a master netting agreement (1) Interest rate derivatives (2) 2,767,518 6,570 1,276,109 2,012 2,791,760 5,977 721,048 1,968 Mortgage banking derivatives (3) 13,599 226 17,000 293 28,497 421 39,230 110 Other 11,952 308 43,097 553 7,914 258 30,328 419 Positions not subject to a master netting agreement (4) Interest rate derivatives 1,668,012 35,635 2,367,876 36,017 1,366,299 23,009 2,146,518 25,631 Risk participation agreements 64,974 39 96,296 81 93,713 80 116,882 111 Other 8,506 450 1,208 54 — — 2,073 184 Total not designated as hedging instruments 4,534,561 43,228 3,801,586 39,010 4,288,183 29,745 3,056,079 28,423 Gross derivative instruments, before netting $ 4,859,561 46,278 $ 3,801,586 39,010 $ 4,613,183 32,515 $ 3,056,079 28,423 Less: Legally enforceable master netting agreements 2,495 2,495 2,245 2,245 Less: Cash collateral posted 4,936 — 6,704 — Total derivative instruments, after netting $ 38,847 $ 36,515 $ 23,566 $ 26,178 (1) The Company has elected to report derivative positions subject to a legally enforceable master netting agreement on a net basis, net of cash collateral. Refer to the Offsetting Derivatives section of this footnote for additional information. (2) Balances related to CME are presented as a single unit of account. Notional amounts of interest rate swaps cleared through CME include $1.9 billion and $1.9 billion for asset derivatives and $1.1 billion and $595 million for liability derivatives at December 31, 2018 and 2017 , respectively, with related fair values of approximately zero. (3) Notional amounts include mandatory forward commitments of $17.0 million , while notional amounts do not include approved floating rate commitments of $6.7 million , at December 31, 2018 . (4) Fair value of assets are included in accrued interest receivable and other assets, while, fair value of liabilities are included in accrued expenses and other liabilities, in the accompanying Consolidated Balance Sheets. Income Statement Impact of Derivative Instruments The following table presents the effect on the income statement from derivative positions: Years ended December 31, (In thousands) 2018 2017 2016 Designated as cash flow hedging instruments: Interest rate derivatives (1) $ 6,557 $ 7,885 $ 9,762 Not designated as hedging instruments: Interest rate derivatives (2) $ 10,376 $ 2,702 $ 8,668 Risk participation agreements (2) 99 242 (361 ) Mortgage banking derivatives (3) (378 ) (2,062 ) 1,553 Other (2) 2,292 (768 ) (67 ) Total not designated as hedging instruments $ 12,389 $ 114 $ 9,793 (1) The impact from interest rate derivatives designated as hedging instruments is included in interest expense on borrowings in the accompanying Consolidated Statements of Income. (2) The impact from these interest rate derivatives not designated as hedging instruments is included in other non-interest income in the accompanying Consolidated Statements of Income. (3) The impact from mortgage banking derivatives is included in mortgage banking activities in the accompanying Consolidated Statements of Income. Amounts for the effective portion of changes in the fair value of derivatives qualifying for hedge accounting treatment are reclassified to interest expense as interest payments are made on Webster's variable-rate debt. Over the next twelve months, the Company estimates that $0.1 million will be reclassified from AOCL as an increase to interest income. Webster records gains and losses related to hedge terminations to AOCL. These balances are subsequently amortized to interest expense over the respective terms of the hedged debt instruments. At December 31, 2018 , the remaining unamortized loss on the terminated cash flow hedges is $8.7 million . Over the next twelve months, the Company estimates that $3.9 million will be reclassified from AOCL as an increase to interest expense. Additional information about cash flow hedge activity impacting AOCL, and the related amounts reclassified to interest expense is provided in Note 12: Accumulated Other Comprehensive Loss, Net of Tax . Information about the valuation methods used to measure the fair value of derivatives is provided in Note 16: Fair Value Measurements . Offsetting Derivatives Non-cleared derivatives subject to a legally enforceable master netting agreement are reported on a net basis, net of cash collateral. Net gain positions are recorded as assets and are included in accrued interest receivable and other assets, while, net loss positions are recorded as liabilities and are included in accrued expenses and other liabilities, in the accompanying Consolidated Balance Sheets. The following table presents the transition from a gross basis to net basis, due to the application of counterparty netting agreements: At December 31, 2018 At December 31, 2017 (In thousands) Gross Amount Relationship Offset Cash Collateral Offset Net Amount Gross Amount Relationship Offset Cash Collateral Offset Net Amount Derivative instrument gains: Hedge accounting $ 3,050 $ 88 $ 567 $ 2,395 $ 2,770 $ 91 $ 2,679 $ — Non-hedge Accounting 6,878 2,407 4,369 102 6,222 2,154 4,025 43 Total assets $ 9,928 $ 2,495 $ 4,936 $ 2,497 $ 8,992 $ 2,245 $ 6,704 $ 43 Derivative instrument losses: Hedge accounting $ — $ — $ — $ — $ — $ — $ — $ — Non-hedge Accounting 2,566 2,495 — 71 2,387 2,245 — 142 Total liabilities $ 2,566 $ 2,495 $ — $ 71 $ 2,387 $ 2,245 $ — $ 142 Derivative Exposure Use of derivative contracts may expose Webster Bank to counterparty credit risk. The Company has International Swaps and Derivatives Association Master Agreements, including a Credit Support Annex, with all derivative counterparties. In accordance with counterparty credit agreements and derivative clearing rules, cash or securities are posted or received on a daily basis to offset counterparty derivative exposure. The Company had approximately $5.6 million in net margin collateral received from financial counterparties or the derivative clearing organization at December 31, 2018 . The net is comprised of $39.5 million in initial margin posted at CME (clearing house), $28.3 million in CME margin received , and $5.6 million in dealer counterparty bi-lateral margin received . Remaining exposure is collateralized by securities received. In the event of default and if the collateral is not returned, the exposure would be offset by terminating the transaction. The Company regularly evaluates the credit risk of its derivative customers, taking into account the likelihood of default, net exposures, and remaining contractual life, among other related factors. Credit risk exposure is mitigated as transactions with customers are generally secured by the same collateral of the underlying transactions being hedged. The Company's net current credit exposure relating to interest rate derivatives with Webster Bank customers was $35.6 million at December 31, 2018 . In addition, the Company monitors potential future exposure, representing its best estimate of exposure to remaining contractual maturity. The potential future exposure relating to interest rate derivatives with Webster Bank customers totaled $35.5 million at December 31, 2018

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2018
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements Fair value is the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. Fair value is best determined using quoted market prices. However, in many instances, quoted market prices are not available. In such instances, fair values are determined using appropriate valuation techniques. Various assumptions and observable inputs must be relied upon in applying these techniques. Accordingly, categorization within the valuation hierarchy is based upon the lowest level of input that is significant to the fair value measurement. As such, the fair value estimates may not be realized in an immediate transfer of the respective asset or liability. 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 entire holdings or any part of a particular financial instrument. 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 factors 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. Fair Value Hierarchy The three levels within the fair value hierarchy are as follows: • Level 1: Valuation is based upon unadjusted quoted prices in active markets for identical assets or liabilities that the reporting entity has the ability to access at the measurement date. • Level 2: Fair value is calculated using significant inputs other than quoted market prices that are directly or indirectly observable for the asset or liability. The valuation may rely on quoted prices for similar assets or liabilities in active markets, quoted prices for identical or similar assets or liabilities in inactive markets, inputs other than quoted prices that are observable for the asset or liability (such as interest rates, volatilities, prepayment speeds, credit ratings, etc.), or inputs that are derived principally or corroborated by market data, by correlation, or other means. • Level 3: Inputs for determining the fair value of the respective assets or liabilities are not observable. Level 3 valuations are reliant upon pricing models and techniques that require significant management judgment or estimation. Assets and Liabilities Measured at Fair Value on a Recurring Basis Available-for-Sale Investment Securities. When quoted prices are available in an active market, the Company classifies investment securities within Level 1 of the valuation hierarchy. U.S. Treasury Bills are classified within Level 1 of the fair value hierarchy. When quoted market prices are not available, the Company employs an independent pricing service that utilizes matrix pricing to calculate fair value. Such fair value measurements consider observable data such as dealer quotes, market spreads, cash flows, yield curves, live trading levels, trade execution data, market consensus prepayments speeds, credit information, and respective terms and conditions for debt instruments. Management maintains procedures to monitor the pricing service's assumptions and establishes processes to challenge the pricing service's valuations that appear unusual unexpected. Available-for-Sale investment securities which include Agency CMO, Agency MBS, Agency CMBS, CMBS, CLO, single issuer-trust preferred, and corporate debt, are classified within Level 2 of the fair value hierarchy. Derivative Instruments. Foreign exchange contracts are valued based on unadjusted quoted prices in active markets and classified within Level 1 of the fair value hierarchy. All other derivative instruments are valued using third-party valuation software, which considers the present value of cash flows discounted using observable forward rate assumptions. The resulting fair values are validated against valuations performed by independent third parties and are classified within Level 2 of the fair value hierarchy. In determining if any fair value adjustment related to credit risk is required, Webster evaluates the credit risk of its counterparties by considering factors such as the likelihood of default by the counterparties, its net exposures, the remaining contractual life, as well as the amount of collateral securing the position. The change in value of derivative assets and liabilities attributable to credit risk was not significant during the reported periods. Webster reviews its counterparty exposure on a regular basis, and, when necessary, appropriate business actions are taken to mitigate the exposure. When determining fair value, Webster applies the portfolio exception with respect to measuring counterparty credit risk for all of its derivative transactions subject to a master netting arrangement. The CME rulebook legally characterizes variation margin payments for over-the-counter derivatives as settlements rather than collateral, which impacts Webster's counterparty relationship with CME, resulting in the fair value of the instrument including cash collateral to be represented as a single unit of account. Mortgage Banking Derivatives. Forward sales of mortgage loans and mortgage-backed securities are utilized by the Company in its efforts to manage risk of loss associated with its mortgage loan commitments and mortgage loans held for sale. Prior to closing and funding certain single-family residential mortgage loans, an interest rate lock commitment is generally extended to the borrower. During the period from commitment date to closing date, the Company is subject to the risk that market rates of interest may change. If market rates rise, investors generally will pay less to purchase such loans resulting in a reduction in the gain on sale of the loans or, possibly, a loss. In an effort to mitigate such risk, forward delivery sales commitments are established, under which the Company agrees to deliver whole mortgage loans to various investors or issue mortgage-backed securities. The fair value of mortgage banking derivatives is determined based on current market prices for similar assets in the secondary market and, therefore, classified within Level 2 of the fair value hierarchy. Originated Loans Held For Sale. Residential mortgage loans typically are classified as held for sale upon origination based on management's intent to sell such loans. The Company generally records residential mortgage loans held for sale under the fair value option of ASC Topic 825 "Financial Instruments." The fair value of residential mortgage loans held for sale is based on quoted market prices of similar loans sold in conjunction with securitization transactions. Accordingly, such loans are classified within Level 2 of the fair value hierarchy. The following table presents the fair value, unpaid principal balance, and accrual status, of assets accounted for under the fair value option: At December 31, 2018 At December 31, 2017 (In thousands) Fair Value Unpaid Principal Balance Difference Fair Value Unpaid Principal Balance Difference Originated loans held for sale $ 7,908 $ 8,227 $ (319 ) $ 20,888 $ 20,346 $ 542 Electing to measure originated loans held for sale at fair value reduces certain timing differences and better matches changes in the value of these assets with changes in the value of the derivatives used as an economic hedge on these assets. Investments Held in Rabbi Trust. Investments held in the Rabbi Trust primarily include mutual funds that invest in equity and fixed income securities. Shares of mutual funds are valued based on net asset value, which represents quoted market prices for the underlying shares held in the mutual funds. Therefore, investments held in the Rabbi Trust are classified within Level 1 of the fair value hierarchy. Webster has elected to measure the investments held in the Rabbi Trust at fair value. The cost basis of the investments held in the Rabbi Trust is $1.9 million as of December 31, 2018 . Alternative Investments. Equity investments have a readily determinable fair value when quoted prices are available in an active market. The Company classifies alternative investments with a readily determinable fair value within Level 1 of the fair value hierarchy. Equity investments that do not have a readily available fair value may qualify for NAV measurement based on specific requirements. The Company's alternative investments accounted for at NAV consist of investments in non-public entities that generally cannot be redeemed since the Company’s investments are distributed as the underlying equity is liquidated. Alternative investments recorded at NAV are not classified within the fair value hierarchy. At December 31, 2018 , these alternative investments had a remaining unfunded commitment of $2.7 million . Summaries of the fair values of assets and liabilities measured at fair value on a recurring basis are as follows: At December 31, 2018 (In thousands) Level 1 Level 2 Level 3 NAV Total Financial assets held at fair value: U.S. Treasury Bills $ 7,550 $ — $ — $ — $ 7,550 Agency CMO — 234,923 — — 234,923 Agency MBS — 1,481,089 — — 1,481,089 Agency CMBS — 566,237 — — 566,237 CMBS — 445,581 — — 445,581 CLO — 112,771 — — 112,771 Single issuer-trust preferred — — — — — Corporate debt — 50,579 — — 50,579 Total available-for-sale investment securities 7,550 2,891,180 — — 2,898,730 Gross derivative instruments, before netting (1) 758 45,520 — — 46,278 Originated loans held for sale — 7,908 — — 7,908 Investments held in Rabbi Trust 4,307 — — — 4,307 Alternative investments — — — 2,563 2,563 Total financial assets held at fair value $ 12,615 $ 2,944,608 $ — $ 2,563 $ 2,959,786 Financial liabilities held at fair value: Gross derivative instruments, before netting (1) $ 588 $ 38,422 $ — $ — $ 39,010 At December 31, 2017 (In thousands) Level 1 Level 2 Level 3 NAV Total Financial assets held at fair value: U.S. Treasury Bills $ 1,247 $ — $ — $ — $ 1,247 Agency CMO — 306,333 — — 306,333 Agency MBS — 1,107,841 — — 1,107,841 Agency CMBS — 588,026 — — 588,026 CMBS — 361,067 — — 361,067 CLO — 209,851 — — 209,851 Single issuer-trust preferred — 7,050 — — 7,050 Corporate debt — 56,622 — — 56,622 Total available-for-sale investment securities 1,247 2,636,790 — — 2,638,037 Gross derivative instruments, before netting (1) 258 32,257 — — 32,515 Originated loans held for sale — 20,888 — — 20,888 Investments held in Rabbi Trust 4,801 — — — 4,801 Alternative investments — — 7,460 — 7,460 Total financial assets held at fair value $ 6,306 $ 2,689,935 $ 7,460 $ — $ 2,703,701 Financial liabilities held at fair value: Gross derivative instruments, before netting (1) $ 587 $ 27,836 $ — $ — $ 28,423 (1) For information relating to the impact of netting derivative assets and derivative liabilities as well as the impact from offsetting cash collateral paid to the same derivative counterparties see Note 15: Derivative Financial Instruments . Assets Measured at Fair Value on a Non-Recurring Basis Certain assets are measured at fair value on a non-recurring basis; that is, the assets are not measured at fair value on an ongoing basis but are subject to fair value adjustments in certain circumstances, for example, when there is evidence of impairment. The following is a description of valuation methodologies used for assets measured on a non-recurring basis. At December 31, 2018 , there were no significant Level 3 assets measured at fair value on a non-recurring basis. Alternative Investments. The measurement alternative has been elected for alternative investments without readily determinable fair values that do not qualify for the NAV practical expedient. The measurement alternative requires investments to be accounted for at cost minus impairment, if any, plus or minus changes resulting from observable price changes in orderly transactions for the identical or a similar investment of the same issuer. These alternative investments are investments in non-public entities that generally cannot be redeemed since the investment is distributed as the underlying equity is liquidated. Accordingly, these alternative investments are classified within Level 2 of the fair value hierarchy. Alternative investments were adjusted by $0.1 million for the year ended December 31, 2018 to reflect observable price changes resulting in a carrying amount of $4.9 million at December 31, 2018 . Transferred Loans Held For Sale. Certain loans are transferred to loans held for sale once a decision has been made to sell such loans. These loans are accounted for at the lower of cost or market and are considered to be recognized at fair value when they are recorded at below cost. This activity primarily consists of commercial loans with observable inputs and is classified within Level 2. On the occasion that these loans should include adjustments for changes in loan characteristics using unobservable inputs, the loans would be classified within Level 3. Collateral Dependent Impaired Loans and Leases. Impaired loans and leases for which repayment is expected to be provided solely by the value of the underlying collateral are considered collateral dependent and are valued based on the estimated fair value of such collateral using customized discounting criteria. As such, collateral dependent impaired loans and leases are classified as Level 3 of the fair value hierarchy. Other Real Estate Owned and Repossessed Assets. The total book value of OREO and repossessed assets was $6.9 million at December 31, 2018 . OREO and repossessed assets are accounted for at the lower of cost or market and are considered to be recognized at fair value when they are recorded at below cost. The fair value of OREO is based on independent appraisals or internal valuation methods, less estimated selling costs. The valuation may consider available pricing guides, auction results, and price opinions. Certain assets require assumptions about factors that are not observable in an active market in the determination of fair value; as such, OREO and repossessed assets are classified within Level 3 of the fair value hierarchy. The Company is required to disclose the estimated fair value of, financial instruments, both assets and liabilities, for which it is practicable to estimate fair value, as well as servicing assets. The following is a description of valuation methodologies used for those assets and liabilities. Cash, Due from Banks, and Interest-bearing Deposits. The carrying amount of cash, due from banks, and interest-bearing deposits is used to approximate fair value, given the short time frame to maturity and, as such, these assets do not present unanticipated credit concerns. Cash, due from banks, and interest-bearing deposits are classified within Level 1 of the fair value hierarchy. Held-to-Maturity Investment Securities. When quoted market prices are not available, the Company employs an independent pricing service that utilizes matrix pricing to calculate fair value. Such fair value measurements consider observable data such as dealer quotes, market spreads, cash flows, yield curves, live trading levels, trade execution data, market consensus prepayments speeds, credit information, and respective terms and conditions for debt instruments. Management maintains procedures to monitor the pricing service's results and establishes processes to challenge their valuations, or methodology, that appear unusual or unexpected. Held-to-Maturity investment securities, which include Agency CMO, Agency MBS, Agency CMBS, CMBS, municipal bonds and notes, and private label MBS securities, are classified within Level 2 of the fair value hierarchy. Loans and Leases, net. The estimated fair value of loans and leases held for investment is calculated using a discounted cash flow method, using future prepayments and market interest rates inclusive of an illiquidity premium for comparable loans and leases. The associated cash flows are adjusted for credit and other potential losses. Fair value for impaired loans and leases is estimated using the net present value of the expected cash flows. Loans and leases are classified within Level 3 of the fair value hierarchy. Deposit Liabilities. The fair value of demand deposits, savings accounts, and certain money market deposits is the amount payable on demand at the reporting date. Deposit liabilities are classified within Level 2 of the fair value hierarchy. Time Deposits. The fair value of a fixed-maturity certificate of deposit is estimated using the rates currently offered for deposits of similar remaining maturities. Time deposits are classified within Level 2 of the fair value hierarchy. Securities Sold Under Agreements to Repurchase and Other Borrowings. The carrying value is an estimate of fair value for those securities sold under agreements to repurchase and other borrowings that mature within 90 days. Fair value of all other borrowings is estimated using discounted cash flow analysis based on current market rates adjusted, as appropriate, for associated credit risks. Securities sold under agreements to repurchase and other borrowings are classified within Level 2 of the fair value hierarchy. Federal Home Loan Bank Advances and Long-Term Debt. The fair value of FHLB advances and long-term debt is estimated using a discounted cash flow technique. Discount rates are matched with the time period of the expected cash flow and are adjusted, as appropriate, to reflect credit risk. FHLB advances and long-term debt are classified within Level 2 of the fair value hierarchy. Mortgage Servicing Assets. Mortgage servicing assets are accounted for at cost and subsequently measured under the amortization method. Mortgage servicing assets are subject to impairment testing and considered to be recognized at fair value when they are recorded at below cost. Amortization, and impairment charges, if any, are included as a component of other non-interest income in the accompanying Condensed Consolidated Statements of Income. Fair value is calculated as the present value of estimated future net servicing income and relies on market based assumptions for loan prepayment speeds, servicing costs, discount rates, and other economic factors; as such, the primary risk inherent in valuing mortgage servicing assets is the impact of fluctuating interest rates on the servicing revenue stream. Mortgage servicing assets are classified within Level 3 of the fair value hierarchy. Fair value of selected financial instruments and servicing assets amounts are as follows: At December 31, 2018 2017 (In thousands) Carrying Amount Fair Value Carrying Amount Fair Financial Assets: Level 2 Held-to-maturity investment securities $ 4,325,420 $ 4,209,121 $ 4,487,392 $ 4,456,350 Transferred loans held for sale — — — — Level 3 Loans and leases, net 18,253,136 18,155,798 17,323,864 17,211,619 Mortgage servicing assets 21,215 45,478 25,139 45,309 Financial Liabilities: Level 2 Deposit liabilities, other than time deposits $ 18,662,299 $ 18,662,299 $ 18,525,321 $ 18,525,321 Time deposits 3,196,546 3,175,948 2,468,408 2,455,245 Securities sold under agreements to repurchase and other borrowings 581,874 581,874 643,269 644,084 FHLB advances (1) 1,826,808 1,826,381 1,677,105 1,678,070 Long-term debt (1) 226,021 229,306 225,767 234,359 (1) Adjustments to the carrying amount of long-term debt for unamortized discount and debt issuance cost on senior fixed-rate notes are not included for determination of fair value. See Note 10: Borrowings

Retirement Benefit Plans

Retirement Benefit Plans	12 Months Ended
	Dec. 31, 2018
Retirement Benefits [Abstract]
Retirement Benefit Plans	Retirement Benefit Plans Defined benefit pension and other postretirement benefits Webster Bank offered a defined benefit noncontributory pension plan through December 31, 2007 for eligible employees who met certain minimum service and age requirements. Pension plan benefits are based upon employee earnings during the period of credited service. A supplemental defined benefit retirement plan (SERP) was also offered to certain employees who were at the Executive Vice President level or above through December 31, 2007. The SERP provides eligible participants with additional pension benefits. Webster Bank also provides other postretirement healthcare benefits to certain retired employees. The Webster Bank Pension Plan and the SERP were frozen as of December 31, 2007. No additional benefits have been accrued since that time. Employees hired on or after January 1, 2007 receive no qualified or supplemental retirement income under the plans. All other employees accrue no additional qualified or supplemental retirement income after January 1, 2008, and the amount of their qualified and supplemental retirement income will not exceed the amount of benefits determined as of December 31, 2007. There were $11.4 million and $122 thousand in company contributions to the SERP for the years ended December 31, 2018 and 2017 , respectively. The mortality assumptions used in the pension liability assessment for the year ended December 31, 2018 were the RP-2014 adjusted to 2006 dataset mortality table projected to measurement date with Mercer's mortality improvement scale MMP-2017. The measurement date is December 31 for the Webster Bank Pension Plan, SERP, and other postretirement healthcare benefits. The following table sets forth changes in benefit obligation, changes in plan assets, and the funded status of the defined benefit pension and other postretirement benefits at December 31: Pension Plan SERP Other Benefits (In thousands) 2018 2017 2018 2017 2018 2017 Change in benefit obligation: Beginning balance $ 229,318 $ 211,508 $ 13,096 $ 11,806 $ 3,094 $ 3,852 Service cost — 50 — — — — Interest cost 7,212 7,314 103 375 78 92 Actuarial loss (gain) (18,499 ) 18,396 — 1,037 (352 ) (631 ) Benefits paid and administrative expenses (8,518 ) (7,950 ) (11,364 ) (122 ) (208 ) (219 ) Ending balance (1) 209,513 229,318 1,835 13,096 2,612 3,094 Change in plan assets: Beginning balance 216,225 192,922 — — — — Actual return on plan assets (15,735 ) 31,253 — — — — Employer contributions — — 11,364 122 208 219 Benefits paid and administrative expenses (8,518 ) (7,950 ) (11,364 ) (122 ) (208 ) (219 ) Ending balance 191,972 216,225 — — — — Funded status of the plan at year end (2) $ (17,541 ) $ (13,093 ) $ (1,835 ) $ (13,096 ) $ (2,612 ) $ (3,094 ) (1) The accumulated benefit obligation for the defined benefit pension and other postretirement benefits was $214.0 million and $245.5 million at December 31, 2018 and 2017 , respectively. (2) The underfunded status amounts are included in accrued expense and other liabilities in the accompanying Consolidated Balance Sheets. The Company expects that $5.7 million in net actuarial loss will be recognized as a component of net periodic benefit cost in 2019 . The components of AOCL related to the defined benefit pension and other postretirement benefits at December 31, 2018 and 2017 are summarized below: Pension Plan SERP Other Benefits (In thousands) 2018 2017 2018 2017 2018 2017 Net actuarial loss (gain) $ 64,523 $ 59,433 $ 453 $ 3,299 $ (368 ) $ (16 ) Prior service cost — — — — — — Total pre-tax amounts included in AOCL 64,523 59,433 453 3,299 (368 ) (16 ) Deferred tax benefit 14,623 13,407 103 744 (83 ) (3 ) Amounts included in accumulated AOCL, net of tax $ 49,900 $ 46,026 $ 350 $ 2,555 $ (285 ) $ (13 ) Expected future benefit payments for the defined benefit pension and other postretirement benefits are presented below: (In thousands) Pension Plan SERP Other Benefits 2019 $ 8,636 $ 130 $ 331 2020 9,011 133 318 2021 9,740 133 301 2022 10,416 133 283 2023 10,468 131 262 2024-2028 57,158 650 978 The components of the net periodic benefit cost (benefit) for the defined benefit pension and other postretirement benefits were as follows for the years ended December 31: Pension Plan SERP Other Benefits (In thousands) 2018 2017 2016 2018 2017 2016 2018 2017 2016 Service cost $ — $ 50 $ 45 $ — $ — $ — $ — $ — $ — Interest cost on benefit obligations 7,212 7,314 8,441 103 375 389 78 92 125 Expected return on plan assets (12,716 ) (12,296 ) (11,461 ) — — — — — — Amortization of prior service cost — — — — — — — — 14 Recognized net loss 4,862 5,864 6,665 2,846 748 426 — — 35 Net periodic benefit cost (benefit) $ (642 ) $ 932 $ 3,690 $ 2,949 $ 1,123 $ 815 $ 78 $ 92 $ 174 Changes in funded status related to the defined benefit pension and other postretirement benefits and recognized as a component of OCI in the accompanying Consolidated Statements of Comprehensive Income as follows for the years ended December 31: Pension Plan SERP Other Benefits (In thousands) 2018 2017 2016 2018 2017 2016 2018 2017 2016 Net (gain) loss $ 9,952 $ (561 ) $ (715 ) $ — $ 1,037 $ 1,023 $ (352 ) $ (631 ) $ 60 Amounts reclassified from AOCL (4,862 ) (5,864 ) (6,665 ) (2,846 ) (748 ) (426 ) — — (35 ) Amortization of prior service cost — — — — — — — — (14 ) Total (gain) loss recognized in OCI $ 5,090 $ (6,425 ) $ (7,380 ) $ (2,846 ) $ 289 $ 597 $ (352 ) $ (631 ) $ 11 Fair Value Measurements The following is a description of the valuation methodologies used for the pension plan assets measured at fair value, including the general classification of such instruments pursuant to the valuation hierarchy: Registered investment companies. Exchange traded funds are quoted at market prices in an exchange and active market, which represent the net asset values of shares held by the plan at year end. Money market funds are shown at cost, which approximates fair value. The exchange traded fund is benchmarked against the Standard & Poor's 500 Index. Common collective trust funds. The net asset value (NAV), as provided by the trustee, is used as the fair value of the investments. The NAV is based on the fair value of the underlying investments held by the fund less its liabilities. Plan transactions (purchases and sales) may occur daily. Were the Plan to initiate a full redemption of the collective trust, the investment adviser reserves the right to temporarily delay withdrawal from the trust in order to ensure that securities liquidations will be carried out in an orderly business manner. The common collective trust funds performance are benchmarked against the Standard and Poor’s 500 Stock Index, the S&P 400 Mid Cap Index, the Russell 2000 Index, the MSCI ACWI ex U.S. Index, and the Barclays Capital U.S. Long Credit Index. A summary of the fair value and hierarchy classification of financial assets of the pension plan is as follows: At December 31, 2018 2017 (In thousands) Level 1 Level 2 Level 3 NAV Total Level 1 Level 2 Level 3 NAV Total Registered investment companies: Exchange traded funds $ 30,641 $ — $ — $ — $ 30,641 $ 37,848 $ — $ — $ — $ 37,848 Cash and cash equivalents 1,695 — — — 1,695 1,115 — — — 1115 Common collective trust funds: Fixed Income funds — — — 107,753 107,753 — 107,430 — — 107,430 Equity Funds — — — 51,883 51,883 — 69,832 — — 69,832 Total $ 32,336 $ — $ — $ 159,636 $ 191,972 $ 38,963 $ 177,262 $ — $ — $ 216,225 All Level 3 assets of the pension plan were sold in 2017. The following table sets forth a summary of changes in the fair value of Level 3 assets of the pension plan: Year ended December 31, (In thousands) 2017 Beginning balance $ 793 Employer contributions 78 Unrealized gains relating to instruments still held at the reporting date — Benefit payments, administrative expenses (166 ) Asset sales (705 ) Ending balance $ — Asset Management The following table presents the target allocation and the pension plan asset allocation for the periods indicated, by asset category: Target Allocation Percentage of Pension Plan assets 2019 2018 2017 Fixed income investments 55 % 56 % 50 % Equity investments 45 43 50 Cash and cash equivalents — % 1 % — % Total 100 % 100 % 100 % The Retirement Plan Committee is a fiduciary under ERISA and is charged with the responsibility for directing and monitoring the investment management of the pension plan. To assist the Retirement Plan Committee in this function, it engages the services of investment managers and advisors who possess the necessary expertise to manage the pension plan assets within the established investment policy guidelines and objectives. The investment policy guidelines and objectives are reviewed at a minimum annually by the Retirement Plan Committee. The primary objective of the pension plan investment strategy is to provide long-term total return through capital appreciation and dividend and interest income. The Plan invests in registered investment companies and bank collective trusts. The volatility, as measured by standard deviation, of the pension plan assets should not exceed that of the Composite Index. The investment policy guidelines allow the pension plan assets to be invested in certain types of cash equivalents, fixed income securities, equity securities, mutual funds, and collective trusts. Investments in mutual funds and collective trust funds are substantially limited to funds with the securities characteristic of their assigned benchmarks. The pension plan investment strategy is designed to maintain a diversified portfolio, with a target average long-term rate of 6.00% , however, there is no certainty that the portfolio will perform to expectations. Asset allocations are monitored monthly, and the portfolio is rebalanced as needed. Weighted-average assumptions used to determine benefit obligations at December 31 are as follows: Pension Plan SERP Other Benefits 2018 2017 2018 2017 2018 2017 Discount rate 4.12 % 3.50 % 3.95 % 3.30 % 3.69 % 3.00 % Rate of compensation increase n/a n/a n/a n/a n/a n/a Weighted-average assumptions used to determine net periodic benefit cost for the years ended December 31 are as follows: Pension Plan SERP Other Benefits 2018 2017 2016 2018 2017 2016 2018 2017 2016 Discount rate 3.50 % 4.01 % 4.20 % 3.30 % 3.63 % 3.75 % 3.00 % 3.27 % 3.35 % Expected long-term return on assets 6.00 % 6.50 % 7.00 % n/a n/a n/a n/a n/a n/a Rate of compensation increase n/a n/a n/a n/a n/a n/a n/a n/a n/a Assumed healthcare cost trend n/a n/a n/a n/a n/a n/a 7.00 % 7.50 % 8.25 % The assumed healthcare cost-trend rate is 7.00% for 2018 and 2019, declining 1.0% each year thereafter until 2024 when the rate will be 4.60% . An increase of 1.0% in the assumed healthcare cost-trend rate for 2018 would have increased the net periodic postretirement benefit cost by $4 thousand and increased the accumulated benefit obligation by $111 thousand . A decrease of 1.0% in the assumed healthcare cost trend rate for 2018 would have decreased the net periodic postretirement benefit cost by $3 thousand and decreased the accumulated postretirement benefit obligation by $102 thousand . Multiple-employer plan Webster Bank, for the benefit of former employees of a bank acquired by the Company, is a sponsor of a multiple-employer pension plan that does not segregate the assets or liabilities of its employers participating in the plan. According to the plan administrator, as of July 1, 2018 , the date of the latest actuarial valuation, Webster Bank’s portion of this plan was under-funded by $2.0 million . The following table sets forth contributions and funding status of Webster Bank's portion of this plan: (Dollars in thousands) Contributions by Webster Bank for the year ended December 31, Funded Status of the Plan at December 31, Plan Name Employer Identification Number Plan Number 2018 2017 2016 2018 2017 Pentegra Defined Benefit Plan for Financial Institutions 13-5645888 333 $679 $614 $690 At least 80 percent At least 80 percent Multi-employer accounting is applied to the Fund. As a multiple-employer pension plan, there are no collective bargained contracts affecting its contribution or benefit provisions. Any shortfall amortization basis is being amortized over seven years, as required by the Pension Protection Act. All benefit accruals were frozen as of September 1, 2004. The Company's contributions to this plan did not exceed more than 5% of total contributions in the plan for the years ended December 31, 2018 , 2017 , and 2016 . Webster Bank Retirement Savings Plan Webster Bank provides an employee retirement savings plan governed by section 401(k) of the Internal Revenue Code. Webster Bank matches 100% of the first 2% and 50% of the next 6% of employees’ pre-tax contributions based on annual compensation. If a participant fails to make a pre-tax contribution election within 90 days of his or her date of hire, automatic pre-tax contributions will commence 90 days after his or her date of hire at a rate equal to 3% of compensation. Compensation and benefit expense included $12.4 million , $12.0 million , and $11.1 million for the years ended December 31, 2018 , 2017 , and 2016

Share-Based Plans

Share-Based Plans	12 Months Ended
	Dec. 31, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Share-Based Plans	Share-Based Plans Stock compensation plans Webster maintains stock compensation plans under which restricted stock, restricted stock units, non-qualified stock options, incentive stock options, or stock appreciation rights may be granted to employees and directors. The Company believes these share awards better align the interests of its employees with those of its shareholders. Stock compensation cost is recognized over the required service vesting period for the awards, based on the grant-date fair value, net of estimated forfeitures, and is included as a component of compensation and benefits reflected in non-interest expense. The Plans have shareholder approval for up to 13.4 million shares of common stock. At December 31, 2018 , there were 2.2 million common shares remaining available for grant, while no stock appreciation rights have been granted. The following table provides a summary of stock compensation expense and income tax benefit associated with stock compensation recognized in the accompanying Consolidated Statements of Income: Years ended December 31, (In thousands) 2018 2017 2016 Restricted stock $ 11,612 $ 12,276 $ 11,395 Stock options — — 43 Stock compensation expense $ 11,612 $ 12,276 $ 11,438 Income tax benefit $ 8,545 $ 11,849 $ 4,132 At December 31, 2018 there was $14.0 million of unrecognized stock compensation expense for restricted stock, expected to be recognized over a weighted-average period of 1.9 years . The following table provides a summary of the activity under the stock compensation plans for the year ended December 31, 2018 : Unvested Restricted Stock Awards Outstanding Stock Options Outstanding Time-Based Performance-Based Number of Shares Weighted-Average Grant Date Fair Value Number of Shares Weighted-Average Grant Date Fair Value Number of Shares Weighted-Average Exercise Price Balance at January 1, 2018 207,800 $ 43.16 78,916 $ 45.35 673,039 $ 18.75 Granted 151,833 58.34 75,707 55.82 — — Vested restricted stock awards (1) 171,269 45.54 71,357 46.50 — — Forfeited 10,923 52.94 13,847 51.19 — — Exercised options — — — — 192,247 11.30 Balance at December 31, 2018 177,441 53.05 69,419 54.43 480,792 21.73 (1) Vested for purposes of recording compensation expense. Time-based restricted stock . Time-based restricted stock awards vest over the applicable service period ranging from 1 to 3 years. The number of time-based awards that may be granted to an eligible individual in a calendar year is limited to 100,000 shares. Compensation expense is recorded over the vesting period based on fair value, which is measured using the Company's common stock closing price at the date of grant. Performance-based restricted stock . Performance-based restricted stock awards vest after a 3 year performance period. The awards vest with a share quantity dependent on that performance, in a range from zero to 150% . The performance criteria for 50% of the shares granted in 2018 is based upon Webster's ranking for total shareholder return versus Webster's compensation peer group companies and the remaining 50% is based upon Webster's average of return on equity during the 3 year vesting period. The compensation peer group companies are utilized because they represent the financial institutions that best compare with Webster. The Company records compensation expense over the vesting period, based on a fair value calculated using the Monte-Carlo simulation model, which allows for the incorporation of the performance condition for the 50% of the performance-based shares tied to total shareholder return versus the compensation peer group, and based on a fair value of the market price on the date of grant for the remaining 50% of the performance-based shares tied to Webster's return on equity. Compensation expense is subject to adjustment based on management's assessment of Webster's return on equity performance relative to the target number of shares condition. The total fair value of restricted stock awards vested during the years ended December 31, 2018 , 2017 , and 2016 was $11.1 million , $12.7 million , and $11.6 million , respectively. Stock options . Stock option awards have an exercise price equal to the market price of Webster Financial Corporation's stock on the date of grant. Each option grants the holder the right to acquire a share of Webster Financial Corporation common stock over a contractual life of up to 10 years. There have been no stock options granted since 2013. All awarded options have vested. There were 446,904 non-qualified stock options and 33,888 incentive stock options outstanding at December 31, 2018 . Aggregate intrinsic value represents the total pretax intrinsic value (the difference between Webster's closing stock price on the last trading day of the year and the weighted-average exercise price, multiplied by the number of shares) that would have been received by the option holders had they all exercised their options at that time. At December 31, 2018 , as all awarded options have vested, all of the outstanding options are exercisable, and the aggregate intrinsic value of these options was $13.3 million . The total intrinsic value of options exercised during the years ended December 31, 2018 , 2017 , and 2016 was $9.7 million , $11.1 million , and $6.4 million , respectively. The following table summarizes information for options, all of which are both outstanding and exercisable, at December 31, 2018 : Range of Exercise Prices Number of Shares Weighted-Average Remaining Contractual Life (years) Weighted-Average Exercise Price $ 5.14 - 12.85 48,568 0.5 $ 7.42 $ 23.00 - 23.81 432,224 3.7 23.34 480,792 3.4 $ 21.73

Segment Reporting

Segment Reporting	12 Months Ended
	Dec. 31, 2018
Segment Reporting [Abstract]
Segment Reporting	Segment Reporting Webster’s operations are organized into three reportable segments that represent its primary businesses - Commercial Banking, HSA Bank, and Community Banking. These three segments reflect how executive management responsibilities are assigned, the primary businesses, the products and services provided, the type of customer served, and how discrete financial information is currently evaluated. The Corporate Treasury unit of the Company, along with the amounts required to reconcile profitability metrics to amounts reported in accordance with GAAP, are included in the Corporate and Reconciling category. Description of Segment Reporting Methodology Webster’s reportable segment results are intended to reflect each segment as if it were a stand-alone business. Webster uses an internal profitability reporting system to generate information by operating segment, which is based on a series of management estimates and allocations regarding funds transfer pricing, provision for loan and lease losses, non-interest expense, income taxes, and equity capital. These estimates and allocations, certain of which are subjective in nature, are periodically reviewed and refined. Changes in estimates and allocations that affect the reported results of any operating segment do not affect the consolidated financial position or results of operations of Webster as a whole. The full profitability measurement reports, which are prepared for each operating segment, reflect non-GAAP reporting methodologies. The differences between full profitability and GAAP results are reconciled in the Corporate and Reconciling category. Webster allocates interest income and interest expense to each business, while also transferring the primary interest rate risk exposures to the Corporate and Reconciling category, using a matched maturity funding concept called FTP. The allocation process considers the specific interest rate risk and liquidity risk of financial instruments and other assets and liabilities in each line of business. The matched maturity funding concept considers the origination date and the earlier of the maturity date or the repricing date of a financial instrument to assign an FTP rate for loans and deposits originated each day. Loans are assigned an FTP rate for funds used and deposits are assigned an FTP rate for funds provided. This process is executed by the Company’s Financial Planning and Analysis division and is overseen by the Company's ALCO. Webster allocates the provision for loan and lease losses to each segment based on management’s estimate of the inherent loss content in each of the specific loan and lease portfolios. Webster allocates a majority of non-interest expense to each reportable segment using a full-absorption costing process. Costs, including corporate overhead, are analyzed, pooled by process, and assigned to the appropriate reportable segment. A charge related to additional FDIC premiums pertaining to prior periods' deposit insurance assessments and related interest is included in the Corporate and Reconciling category for the year ended December 31, 2018 . See Note 1 to the Consolidated Financial Statements included in Item 1 of this report for additional information. Beginning in 2018, income tax expense is estimated for each reportable segment individually. The 2017 and 2016 income tax expense was estimated for all segments using the consolidated effective tax rate. This change in the estimate of income tax expense reflects an estimate of full profitability for each of the individual business segments based on the nature of their operations. The following table presents total assets for Webster's reportable segments and the Corporate and Reconciling category: Total Assets (In thousands) Commercial HSA Community Banking Corporate and Consolidated At December 31, 2018 $ 10,477,050 $ 70,826 $ 8,727,335 $ 8,335,104 $ 27,610,315 At December 31, 2017 9,350,028 76,308 8,909,671 8,151,638 26,487,645 The following tables present the operating results, including all appropriate allocations, for Webster’s reportable segments and the Corporate and Reconciling category: Year ended December 31, 2018 (In thousands) Commercial HSA Community Banking Corporate and Consolidated Net interest income $ 356,509 $ 143,255 $ 404,869 $ 2,048 $ 906,681 Provision for loan and lease losses 34,773 — 7,227 — 42,000 Net interest income after provision for loan and lease losses 321,736 143,255 397,642 2,048 864,681 Non-interest income 64,765 89,323 109,669 18,811 282,568 Non-interest expense 174,054 124,594 384,599 22,369 705,616 Income (loss) before income tax expense 212,447 107,984 122,712 (1,510 ) 441,633 Income tax expense (benefit) 52,262 28,076 24,420 (23,543 ) 81,215 Net income $ 160,185 $ 79,908 $ 98,292 $ 22,033 $ 360,418 Year ended December 31, 2017 (In thousands) Commercial HSA Community Banking Corporate and Consolidated Net interest income (loss) $ 322,393 $ 104,704 $ 383,700 $ (14,510 ) $ 796,287 Provision for loan and lease losses 38,518 — 2,382 — 40,900 Net interest income (loss) after provision for loan and lease losses 283,875 104,704 381,318 (14,510 ) 755,387 Non-interest income 55,194 77,378 107,368 19,538 259,478 Non-interest expense 154,037 113,143 373,081 20,814 661,075 Income (loss) before income tax expense 185,032 68,939 115,605 (15,786 ) 353,790 Income tax expense (benefit) 51,438 19,165 32,137 (4,389 ) 98,351 Net income (loss) $ 133,594 $ 49,774 $ 83,468 $ (11,397 ) $ 255,439 Year ended December 31, 2016 (In thousands) Commercial HSA Community Banking Corporate and Consolidated Net interest income (loss) $ 287,596 $ 81,451 $ 367,137 $ (17,671 ) $ 718,513 Provision for loan and lease losses 37,455 — 18,895 — 56,350 Net interest income (loss) after provision for loan and lease losses 250,141 81,451 348,242 (17,671 ) 662,163 Non-interest income 57,253 71,710 110,197 25,318 264,478 Non-interest expense 138,379 97,152 369,132 18,528 623,191 Income (loss) before income tax expense 169,015 56,009 89,307 (10,881 ) 303,450 Income tax expense (benefit) 53,649 17,779 28,348 (3,453 ) 96,323 Net income (loss) $ 115,366 $ 38,230 $ 60,959 $ (7,428 ) $ 207,127

Revenue from contracts with Cus

Revenue from contracts with Customers Revenue from Contracts with Customers	12 Months Ended
	Dec. 31, 2018
Revenue from Contract with Customer [Abstract]
Revenue from Contract with Customer [Text Block]	Revenue from Contracts with Customers The following tables present the disaggregation by operating segment and major revenue stream, with disaggregated revenue reconciled to segment revenue as presented in Note 19: Segment Reporting : Year ended December 31, 2018 (In thousands) Commercial HSA Community Corporate and Consolidated Major Revenue Streams Deposit service fees $ 12,775 $ 85,809 $ 63,522 $ 77 $ 162,183 Wealth and investment services 10,145 — 22,732 (34 ) 32,843 Other income — 3,514 2,133 — 5,647 Revenue from contracts with customers 22,920 89,323 88,387 43 200,673 Non-interest income within the scope of other GAAP topics 41,845 — 21,282 18,768 81,895 Total non-interest income $ 64,765 $ 89,323 $ 109,669 $ 18,811 $ 282,568 Year ended December 31, 2017 (In thousands) Commercial HSA Community Corporate and Consolidated Major Revenue Streams Deposit service fees $ 12,203 $ 74,448 $ 64,194 $ 292 $ 151,137 Wealth and investment services 9,817 — 21,274 (36 ) 31,055 Other income — 2,930 823 — 3,753 Revenue from contracts with customers 22,020 77,378 86,291 256 185,945 Non-interest income within the scope of other GAAP topics 33,174 — 21,077 19,282 73,533 Total non-interest income $ 55,194 $ 77,378 $ 107,368 $ 19,538 $ 259,478 Year ended December 31, 2016 (In thousands) Commercial HSA Community Corporate and Consolidated Major Revenue Streams Deposit service fees $ 11,143 $ 66,162 $ 63,143 $ 237 $ 140,685 Wealth and investment services 9,150 — 19,842 (30 ) 28,962 Other income — 2,858 872 — 3,730 Revenue from contracts with customers 20,293 69,020 83,857 207 173,377 Non-interest income within the scope of other GAAP topics 36,960 2,690 26,340 25,111 91,101 Total non-interest income $ 57,253 $ 71,710 $ 110,197 $ 25,318 $ 264,478

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2018
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Lease Commitments Webster is obligated under various non-cancelable operating leases for properties used as banking centers and other office facilities. Rental expense under the leases was $31.0 million , $31.1 million , and $30.4 million for the years ended December 31, 2018 , 2017 , and 2016 , respectively, and is recorded as a component of occupancy expense in the accompanying Consolidated Statements of Income. Rental income from sub-leases on certain of these properties is netted as a component of occupancy expense, while rental income under various non-cancelable operating leases for properties owned is recorded as a component of other non-interest income in the accompanying Consolidated Statements of Income. Rental income was $0.7 million , $0.7 million , and $0.8 million for the years ended December 31, 2018 , 2017 , and 2016 , respectively. The following table summarizes future minimum rental payments and receipts under lease agreements: At December 31, 2018 (In thousands) Rental Payments Rental Receipts 2019 $ 30,889 $ 805 2020 30,049 667 2021 28,274 547 2022 24,498 493 2023 21,231 427 Thereafter 78,882 1,403 Total future minimum rental payments and receipts $ 213,823 $ 4,342 Credit-Related Financial Instruments The Company offers credit-related financial instruments, in the normal course of business to meet certain financing needs of its customers, that involve off-balance sheet risk. These transactions may include an unused commitment to extend credit, standby letter of credit, or commercial letter of credit. Such transactions involve, to varying degrees, elements of credit risk. The following table summarizes the outstanding amounts of credit-related financial instruments with off-balance sheet risk: At December 31, (In thousands) 2018 2017 Commitments to extend credit $ 5,840,585 $ 5,567,687 Standby letter of credit 189,040 195,902 Commercial letter of credit 21,181 43,200 Total credit-related financial instruments with off-balance sheet risk $ 6,050,806 $ 5,806,789 Commitments to Extend Credit . The Company makes commitments under various terms to lend funds to customers at a future point in time. These commitments include revolving credit arrangements, term loan commitments, and short-term borrowing agreements. Most of these loans have fixed expiration dates or other termination clauses where a fee may be required. Since commitments routinely expire without being funded, or after required availability of collateral occurs, the total commitment amount does not necessarily represent future liquidity requirements. Standby Letter of Credit . A standby letter of credit commits the Company to make payments on behalf of customers if certain specified future events occur. The Company has recourse against the customer for any amount required to be paid to a third party under a standby letter of credit, which is often part of a larger credit agreement under which security is provided. Historically, a large percentage of standby letters of credit expire without being funded. The contractual amount of a standby letter of credit represents the maximum amount of potential future payments the Company could be required to make, and is the Company's maximum credit risk. Commercial Letter of Credit . A commercial letter of credit is issued to facilitate either domestic or foreign trade arrangements for customers. As a general rule, drafts are committed to be drawn when the goods underlying the transaction are in transit. Similar to a standby letter of credit, a commercial letter of credit is often secured by an underlying security agreement including the assets or inventory they relate to. These commitments subject the Company to potential exposure in excess of amounts recorded in the financial statements, and therefore, management maintains a specific reserve for unfunded credit commitments. This reserve is reported as a component of accrued expenses and other liabilities in the accompanying Consolidated Balance Sheets. The following table provides a summary of activity in the reserve for unfunded credit commitments: Years ended December 31, (In thousands) 2018 2017 2016 Beginning balance $ 2,362 $ 2,287 $ 2,119 Provision 144 75 168 Ending balance $ 2,506 $ 2,362 $ 2,287 Litigation Webster is involved in routine legal proceedings occurring in the ordinary course of business and is subject to loss contingencies related to such litigation and claims arising therefrom. Webster evaluates these contingencies based on information currently available, including advice of counsel and assessment of available insurance coverage. Webster establishes accruals for litigation and claims when a loss contingency is considered probable and the related amount is reasonably estimable. These accruals are periodically reviewed and may be adjusted as circumstances change. Webster also estimates certain loss contingencies for possible litigation and claims, whether or not there is an accrued probable loss. Webster believes it has defenses to all the claims asserted against it in existing litigation matters and intends to defend itself in all matters. Based upon its current knowledge, after consultation with counsel and after taking into consideration its current litigation accruals, Webster believes that at December 31, 2018

Parent Company Information

Parent Company Information	12 Months Ended
	Dec. 31, 2018
Condensed Financial Information Disclosure [Abstract]
Parent Company Information	Financial information for the Parent Company only is presented in the following tables: Condensed Balance Sheets December 31, (In thousands) 2018 2017 Assets: Cash and due from banks $ 317,473 $ 181,085 Intercompany debt securities 150,000 150,000 Investment in subsidiaries 2,633,848 2,585,955 Due from subsidiaries 36 — Alternative investments 3,252 2,939 Other assets 12,003 13,252 Total assets $ 3,116,612 $ 2,933,231 Liabilities and shareholders’ equity: Senior notes $ 148,701 $ 148,447 Junior subordinated debt 77,320 77,320 Accrued interest payable 2,664 2,616 Due to subsidiaries — 575 Other liabilities 1,412 2,315 Total liabilities 230,097 231,273 Shareholders’ equity 2,886,515 2,701,958 Total liabilities and shareholders’ equity $ 3,116,612 $ 2,933,231 Condensed Statements of Income Years ended December 31, (In thousands) 2018 2017 2016 Operating Income: Dividend income from bank subsidiary $ 290,000 $ 120,000 $ 145,000 Interest on securities and deposits 7,342 4,477 1,911 Loss on sale of investment securities — — (2,410 ) Alternative investments income 290 1,504 176 Other non-interest income 805 204 7,485 Total operating income 298,437 126,185 152,162 Operating Expense: Interest expense on borrowings 11,127 10,380 9,981 Non-interest expense 19,105 23,008 17,739 Total operating expense 30,232 33,388 27,720 Income before income tax benefit and equity in undistributed earnings of subsidiaries 268,205 92,797 124,442 Income tax benefit 2,207 3,004 3,086 Equity in undistributed earnings of subsidiaries 90,006 159,638 79,599 Net income $ 360,418 $ 255,439 $ 207,127 Condensed Statements of Comprehensive Income Years ended December 31, (In thousands) 2018 2017 2016 Net income $ 360,418 $ 255,439 $ 207,127 Other comprehensive income (loss), net of tax: Net unrealized gains on available for sale securities — — 584 Net unrealized gains on derivative instruments 1,447 1,216 1,223 Other comprehensive loss of subsidiaries and associated companies (40,568 ) (106 ) (694 ) Other comprehensive income (loss), net of tax (39,121 ) 1,110 1,113 Comprehensive income $ 321,297 $ 256,549 $ 208,240 Condensed Statements of Cash Flows Years ended December 31, (In thousands) 2018 2017 2016 Net cash provided by operating activities $ 282,986 $ 115,957 $ 127,899 Investing activities: Proceeds from sale of available for sale securities — — 1,089 Purchases of intercompany debt securities — — (150,000 ) Proceeds from the sale of other assets — 7,581 — Net cash provided by (used for) investing activities — 7,581 (148,911 ) Financing activities: Preferred stock issued — 145,056 — Preferred stock redeemed — (122,710 ) — Cash dividends paid to common shareholders (114,959 ) (94,630 ) (89,522 ) Cash dividends paid to preferred shareholders (7,875 ) (8,096 ) (8,096 ) Exercise of stock options 2,173 8,259 11,762 Excess tax benefits from stock-based compensation — — 3,204 Common stock repurchased and acquired from stock compensation plan activity (25,937 ) (23,279 ) (22,870 ) Common stock warrants repurchased — — (163 ) Net cash used for financing activities (146,598 ) (95,400 ) (105,685 ) Increase (decrease) in cash and due from banks 136,388 28,138 (126,697 ) Cash and due from banks at beginning of year 181,085 152,947 279,644 Cash and due from banks at end of year $ 317,473 $ 181,085 $ 152,947

Selected Quarterly Consolidated

Selected Quarterly Consolidated Financial Information (Unaudited)	12 Months Ended
	Dec. 31, 2018
Selected Quarterly Financial Information [Abstract]
Selected Quarterly Consolidated Financial Information (Unaudited)	2018 (In thousands, except per share data) First Quarter Second Quarter Third Quarter Fourth Quarter Interest income $ 245,921 $ 260,491 $ 268,363 $ 280,392 Interest expense 31,753 35,481 37,991 43,261 Net interest income 214,168 225,010 230,372 237,131 Provision for loan and lease losses 11,000 10,500 10,500 10,000 Non-interest income 68,747 68,374 72,284 73,163 Non-interest expense 171,615 180,459 178,783 174,759 Income before income tax expense 100,300 102,425 113,373 125,535 Income tax expense 20,075 20,743 13,700 26,697 Net income $ 80,225 $ 81,682 $ 99,673 $ 98,838 Earnings applicable to common shareholders $ 78,083 $ 79,489 $ 97,460 $ 96,666 Earnings per common share: Basic $ 0.85 $ 0.87 $ 1.06 $ 1.05 Diluted 0.85 0.86 1.06 1.05 2017 (In thousands, except per share data) First Quarter Second Quarter Third Quarter Fourth Quarter Interest income $ 219,680 $ 226,789 $ 231,021 $ 236,115 Interest expense 27,016 29,002 30,117 31,183 Net interest income 192,664 197,787 200,904 204,932 Provision for loan and lease losses 10,500 7,250 10,150 13,000 Non-interest income 63,042 64,551 65,846 66,039 Non-interest expense 163,784 164,419 161,823 171,049 Income before income tax expense 81,422 90,669 94,777 86,922 Income tax expense 21,951 29,090 30,281 17,029 Net income $ 59,471 $ 61,579 $ 64,496 $ 69,893 Earnings applicable to common shareholders $ 57,342 $ 59,485 $ 62,426 $ 67,710 Earnings per common share: Basic $ 0.62 $ 0.65 $ 0.68 $ 0.74 Diluted 0.62 0.64 0.67 0.73

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	Basis of Presentation The accounting and reporting policies of the Company that materially affect its financial statements conform with GAAP, and to general practices within the financial services industry. The Consolidated Financial Statements and the accompanying Notes thereto include the accounts of Webster Financial Corporation and all other entities in which it has a controlling financial interest. Intercompany accounts and transactions have been eliminated in consolidation. Assets that the Company holds or manages in a fiduciary or agency capacity for customers, typically referred to as assets under administration or assets under management are not included in the accompanying Consolidated Balance Sheets since those assets are not Webster's, and the Company is not the primary beneficiary.
Variable Interest Entities	Principles of Consolidation The purpose of consolidated financial statements is to present the results of operations and the financial position of the Company and its subsidiaries as if the consolidated group were a single economic entity. In accordance with the applicable accounting guidance for consolidations, the consolidated financial statements include any voting interest entities (VOEs) in which the Company has a controlling financial interest and any variable interest entities (VIEs) for which the Company is deemed to be the primary beneficiary. The Company generally consolidates its VOEs if the Company, directly or indirectly, owns more than 50% of the outstanding voting shares of the entity and the non-controlling shareholders do not hold any substantive participating or controlling rights. A VIE is an entity that has either a total equity investment that is insufficient to finance its activities without additional subordinated financial support or whose equity investors lack the ability to control the entity’s activities or lack the ability to receive expected benefits or absorb obligations in a manner that is consistent with their investment in the entity. The Company evaluates each VIE to understand the purpose and design of the entity, and its involvement in the ongoing activities of the VIE and will consolidate the VIE if it has (i) the power to direct the activities of the VIE that most significantly affect the VIE's economic performance and (ii) an obligation to absorb losses of the VIE, or the right to receive benefits from the VIE, that could potentially be significant to the VIE.
Use of Estimates	Use of EstimatesThe preparation of financial statements in accordance with GAAP, requires management to make estimates and assumptions that affect the amounts of assets and liabilities as of the date of the financial statements as well as income and expense during the period. Actual results could differ from those estimates.
Cash Equivalents	Cash Equivalents Cash equivalents have a maturity of three months or less. Cash and due from banks. Cash equivalents, including cash on hand, certain cash due from banks and deposits at the FRB of Boston, are referenced as cash and due from banks in the accompanying Consolidated Balance Sheets and Consolidated Statements of Cash Flows. Interest-bearing deposits. Cash equivalents, primarily representing deposits at the FRB of Boston in excess of reserve requirements, and federal funds sold, which essentially represent uncollateralized loans to other financial institutions, are referenced as interest-bearing deposits in the accompanying Consolidated Balance Sheets and Consolidated Statements of Cash Flows. The Company regularly evaluates the credit risk associated with those financial institutions to assure that Webster not become exposed to any significant credit risk on cash equivalents.
Investment Securities	Investment in Debt Securities Investment securities are classified as available-for-sale or held-to-maturity at the time of purchase. Any classification change subsequent to trade date is reviewed for compliance with corporate objectives and accounting policy. Debt securities classified as held-to-maturity are those which Webster has the ability and intent to hold to maturity. Securities classified as held-to-maturity are recorded at amortized cost net of unamortized premiums and discounts. Discount accretion income and premium amortization expense are recognized as interest income according to a constant yield methodology, with consideration given to prepayment assumptions on mortgage backed securities. Premiums are amortized to the earliest call date for debt securities purchased at a premium, with explicit, non-contingent call features and are callable at a fixed price and preset date. Securities classified as available-for-sale are recorded at fair value with unrealized gains and losses recorded as a component of other comprehensive income (OCI) or other comprehensive loss (OCL). Should securities be transferred from available-for-sale to held-to-maturity they would be recorded at fair value at the time of transfer and the respective gain or loss would be recorded as a separate component of OCI or OCL and amortized as an adjustment to interest income over the remaining life of such security. Securities classified as available-for-sale or held-to-maturity and in an unrealized loss position are evaluated for OTTI on a quarterly basis. The evaluation considers several qualitative factors, including the period of time the security has been in a loss position, and the amount of the unrealized loss. If the Company intends to sell a debt security or it is more likely than not the Company will be required to sell the debt security prior to recovery of its amortized cost basis, it is written down to fair value, and the loss is recognized in non-interest income. If the Company does not intend to sell the debt security and it is more likely than not that the Company will not be required to sell the debt security prior to recovery of its amortized cost basis, only the credit component of the unrealized loss is recorded as an impairment charge in non-interest income. The remaining loss component would be recorded to accumulated other comprehensive loss, net of tax (AOCL). The specific identification method is used to determine realized gains and losses on sales of securities. See Note 3: Investment Securities for further information. Investment in Equity Securities The Company’s accounting treatment for equity investments differs for those with and without readily determinable fair values. Equity investments with readily determinable fair values are recorded at fair value with changes in fair value recorded in non-interest income. For equity investments without readily determinable fair values, the Company elected the “measurement alternative,” and therefore carry these investments at cost, less impairment (if any), plus or minus changes in observable prices. Certain equity investments that do not have a readily available fair value may qualify for net asset value (NAV) measurement based on specific requirements. The Company's alternative investments accounted for at NAV consist of investments in non-public entities that generally cannot be redeemed since the Company’s investments are distributed as the underlying equity is liquidated. On a quarterly basis, the Company reviews its equity investments without readily determinable fair values for impairment. If the equity investment is considered impaired, an impairment loss equal to the amount by which the carrying value exceeds its fair value is recorded through a charge to earnings. The impairment loss may be reversed in a subsequent period if there are observable transactions for the identical or similar investment of the same issuer at a higher amount than the carrying amount that was established when the impairment was recognized. Impairment as well as upward or downward adjustments resulting from observable price changes in orderly transactions for identical or similar investments are included in non-interest income. Equity investments in entities that finance affordable housing and other community development projects provide a return primarily through the realization of tax benefits. The Company applies the proportional amortization method to account for its investments in qualified affordable housing projects. Investment in Federal Home Loan Bank and Federal Reserve Bank Stock
Loans Held for Sale	Loans Held for Sale Residential mortgage loans that are classified as held for sale at the time of origination are accounted for under the fair value option method. Loans not originated for sale but subsequently transferred to held for sale are valued at the lower of cost or fair value method of accounting and are valued on an individual asset basis. Any cost amount in excess of fair value is recorded as a valuation allowance and recognized as a reduction of other non-interest income. Gains or losses on the sale of loans held for sale are recorded as mortgage banking activities. Cash flows from the sale of loans that were originated specifically for resale are presented as operating cash flows. Cash flows from the sale of loans originated for investment then subsequently transferred to held for sale are presented as investing cash flows. See Note 5: Transfers of Financial Assets
Transfers and Servicing of Financial Assets	Transfers and Servicing of Financial Assets Transfers of financial assets are accounted for as sales when control over the assets has been surrendered. Control over transferred assets is generally considered to have been surrendered when: (i) the transferred assets are legally isolated from the Company or its consolidated affiliates, even in bankruptcy or other receivership; (ii) the transferee has the right to pledge or exchange the assets with no conditions that constrain the transferee and provide more than a trivial benefit to the Company; and (iii) the Company does not maintain the obligation or unilateral ability to reclaim or repurchase the assets. The Company sells financial assets in the normal course of business, the majority of which are residential mortgage loan sales, primarily to government-sponsored enterprises through established programs, commercial loan sales through participation agreements, and other individual or portfolio loan and securities sales. In accordance with accounting guidance for asset transfers, the Company considers any ongoing involvement with transferred assets in determining whether the assets can be derecognized from the balance sheet. With the exception of servicing and certain performance-based guarantees, the Company’s continuing involvement with financial assets sold is minimal and generally limited to market customary representation and warranty clauses covering certain characteristics of the mortgage loans sold and the Company's origination process. The gain or loss on sale depends on the previous carrying amount of the transferred financial assets, the consideration received, and any other assets obtained or liabilities incurred in exchange for the transferred assets. When the Company sells financial assets, it may retain servicing rights and/or other interests in the financial assets. Servicing assets and any other interests held by the Company are recorded at fair value upon transfer, and thereafter are carried at the lower of cost or fair value. See Note 5: Transfers of Financial Assets
Loans and Leases	Loans and Leases Loans and leases are stated at the principal amount outstanding, net of amounts charged off, unearned income, unamortized premiums and discounts, and deferred loan and lease fees/costs which are recognized as yield adjustments using the interest method. These yield adjustments are amortized over the contractual life of the related loans and leases adjusted for prepayments when applicable. Interest on loans and leases is credited to interest income as earned based on the interest rate applied to principal amounts outstanding. Prepayment fees are recognized in non-interest income. Cash flows from loans and leases are presented as investing cash flows. Loans and leases are placed on non-accrual status when collection of principal and interest in accordance with contractual terms is doubtful, generally when principal or interest payments become 90 days delinquent, unless the loan or lease is well secured and in process of collection, or sooner if management concludes circumstances indicate that the borrower may be unable to meet contractual principal or interest payments. Residential real estate loans, excluding loans fully insured against loss and in the process of collection, and consumer loans are placed on non-accrual status at 90 days past due, or at the date when the Company is notified that the borrower is discharged in bankruptcy. A charge-off for the balance in excess of the fair value of the collateral less cost to sell, is recorded at 180 days if the loan balance exceeds the fair value of the collateral less costs to sell. Residential loans that are more than 90 days past due, fully insured against loss, and in the process of collection, remain accruing and are reported as 90 days or more past due and accruing. Commercial, commercial real estate loans, and equipment finance loans or leases are subject to a detailed review when 90 days past due to determine accrual status, or when payment is uncertain and a specific consideration is made to put a loan or lease on non-accrual status. When loans and leases are placed on non-accrual status, the accrual of interest is discontinued, and any unpaid accrued interest is reversed and charged against interest income. If ultimate repayment of a non-accrual loan or lease is expected, any payments received are applied in accordance with contractual terms. If ultimate repayment is not expected on commercial, commercial real estate, and equipment finance loans and leases, any payment received on a non-accrual loan or lease is applied to principal until the unpaid balance has been fully recovered. Any excess is then credited to interest income when received. If the Company determines, through a current valuation analysis, that principal can be repaid on residential real estate and consumer loans, interest payments may be taken into income as received on a cash basis. Loans are generally removed from non-accrual status when they become current as to principal and interest or demonstrate a period of performance under contractual terms and, in the opinion of management, are fully collectible as to principal and interest. Pursuant to regulatory guidance, a loan discharged under Chapter 7 of the U.S. bankruptcy code is removed from non-accrual status when the bank expects full repayment of the remaining pre-discharged contractual principal and interest, the loan is a closed-end amortizing loan, it is fully collateralized, and post-discharge the loan had at least six consecutive months of current payments. See Note 4: Loans and Leases
Allowance for Loan and Lease Losses and Reserve for Unfunded Commitments	Allowance for Loan and Lease Losses The ALLL is a reserve established through a provision for loan and lease losses charged to expense and represents management’s best estimate of probable losses that may be incurred within the existing loan and lease portfolio as of the balance sheet date. The level of the allowance reflects management’s view of trends in losses, current portfolio quality, and present economic, political, and regulatory conditions. The ALLL may be allocated for specific portfolio segments; however, the entire allowance balance is available to absorb credit losses inherent in the total loan and lease portfolio. A charge-off is recorded when all or a portion of the loan or lease is deemed to be uncollectible. Back-testing is performed to compare original estimated losses and actual observed losses, resulting in ongoing refinements. While management utilizes its best judgment based on the information available at the time, the ultimate adequacy of the allowance is dependent upon a variety of factors that are beyond the Company’s control, which include the performance of the Company’s portfolio, economic conditions, interest rate sensitivity, and other external factors. The ALLL consists of the following three elements: (i) specific valuation allowances established for probable losses on impaired loans and leases; (ii) quantitative valuation allowances calculated using loss experience for like loans and leases with similar characteristics and trends, adjusted, as necessary, to reflect the impact of current conditions; and (iii) qualitative factors determined based on general economic conditions and other factors that may be internal or external to the Company. Loans and leases are considered impaired when, based on current information and events, it is probable the Company will be unable to collect all amounts due in accordance with the original contractual terms of the loan agreement, including scheduled principal and interest payments. Impairment is evaluated on a pooled basis for smaller-balance homogeneous residential, consumer loans and small business loans. Commercial, commercial real estate, and equipment financing loans and leases over a specific dollar amount and all TDR are evaluated individually for impairment. A loan identified as a TDR is considered an impaired loan for the entire term of the loan, with few exceptions. If a loan is impaired, a specific valuation allowance may be established, and the loan is reported net, at the present value of estimated future cash flows using the loan’s original interest rate or at the fair value of collateral less cost to sell if repayment is expected from collateral liquidation. Interest payments on non-accruing impaired loans are typically applied to principal unless collectability of the principal amount is reasonably assured, in which case interest is recognized on a cash basis. Loans and leases, or portions thereof, are charged off when deemed uncollectible. Factors considered by management in determining impairment include payment status, collateral value, discharged bankruptcy, and the likelihood of collecting scheduled principal and interest payments. The current or weighted-average (for multiple notes within a commercial borrowing arrangement) interest rate of the loan is used as the discount rate, for determining net present value of the loan evaluated for impairment, when the interest rate floats with a specified index. A change in terms or payments would be included in the impairment calculation. See Note 4: Loans and Leases for further information. Reserve for Unfunded Commitments The reserve for unfunded commitments provides for probable losses inherent with funding the unused portion of legal commitments to lend. The unfunded reserve calculation includes factors that are consistent with the ALLL methodology for funded loans using the PD, LGD, and a draw down factor applied to the underlying borrower risk and facility grades. The reserve for unfunded credit commitments is included within other liabilities in the accompanying Consolidated Balance Sheets, and changes in the reserve are reported as a component of other non-interest expense in the accompanying Consolidated Statements of Income. See Note 21: Commitments and Contingencies
Troubled Debt Restructurings	Troubled Debt Restructurings A modified loan is considered a TDR when the following two conditions are met: (i) the borrower is experiencing financial difficulties; and (ii) the modification constitutes a concession. The Company considers all aspects of the restructuring in determining whether a concession has been granted, including the debtor's ability to access funds at a market rate. In general, a concession exists when the modified terms of the loan are more attractive to the borrower than standard market terms. Modified terms are dependent upon the financial position and needs of the individual borrower. The most common types of modifications include covenant modifications and forbearance. Loans for which the borrower has been discharged under Chapter 7 bankruptcy are considered collateral dependent TDR, impaired at the date of discharge, and charged down to the fair value of collateral less cost to sell, if management considers that loss potential likely exists. The Company’s policy is to place consumer loan TDR, except those that were performing prior to TDR status, on non-accrual status for a minimum period of six months. Commercial TDR are evaluated on a case-by-case basis for determination of whether or not to place them on non-accrual status. Loans qualify for return to accrual status once they have demonstrated performance with the restructured terms of the loan agreement for a minimum of six months. Initially, all TDRs are reported as impaired. Generally, TDRs are classified as impaired loans and reported as TDR for the remaining life of the loan. Impaired and TDR classification may be removed if the borrower demonstrates compliance with the modified terms for a minimum of six months and through a fiscal year-end and the restructuring agreement specifies a market rate of interest equal to that which would be provided to a borrower with similar credit at the time of restructuring. In the limited circumstance that a loan is removed from TDR classification, it is the Company’s policy to continue to base its measure of loan impairment on the contractual terms specified by the loan agreement. See Note 4: Loans and Leases
Foreclosed and Repossessed Assets	Foreclosed and Repossessed Assets Real estate acquired through foreclosure or completion of a deed in lieu of foreclosure and other assets acquired through repossession are carried at the lower of cost or market value less estimated selling costs and are included within other assets in the accompanying Consolidated Balance Sheets. Independent appraisals generally are obtained to substantiate fair value and may be subject to adjustment based upon historical experience or specific geographic trends impacting the property. Within 90 days
Premises and Equipment	Premises and Equipment Premises and equipment are carried at cost, less accumulated depreciation. Depreciation of premises and equipment is computed on a straight-line basis over the estimated useful lives of the assets, as follows: Minimum Maximum Building and Improvements 5 - 40 years Leasehold improvements 5 - 20 years (or term or lease, if shorter) Fixtures and equipment 5 - 10 years Data processing and software 3 - 7 years Repairs and maintenance costs are charged to non-interest expense as incurred. Premises and equipment that is actively marketed for sale is reclassified to assets held for disposition. The cost and accumulated depreciation relating to premises and equipment retired or otherwise disposed of are eliminated, and any resulting losses are charged to non-interest expense. See Note 6: Premises and Equipment
Goodwill	Goodwill Goodwill represents the excess purchase price of businesses acquired over the fair value of the identifiable net assets acquired and is assigned to specific reporting units. Goodwill is not subject to amortization but rather is evaluated for impairment annually, or more frequently in interim periods if events occur or circumstances change indicating it would more likely than not result in a reduction of the fair value of a reporting unit below its carrying value. Goodwill is evaluated for impairment by performing a qualitative assessment to determine whether it is more likely than not that the fair value of the reporting unit is less than its carrying amount, including goodwill. If the qualitative assessment indicates it is more likely than not that the fair value of the reporting unit is less than its carrying amount, including goodwill, then a 2 Step quantitative process will be performed that will require the Company to utilize an equally weighted combined income and market approach to arrive at an indicated fair value range for the reporting unit. In Step 1, the fair value of a reporting unit is compared to its carrying amount, including goodwill, to ascertain if a goodwill impairment exists. If the fair value of the reporting unit exceeds its carrying amount, goodwill of the reporting unit is not considered impaired, and it is not necessary to continue to Step 2 of the impairment process. Otherwise, Step 2 is performed where the implied fair value of goodwill is compared to the carrying value of goodwill in the reporting unit. If a reporting unit's carrying value exceeds fair value, the difference is charged to non-interest expense. The Company applied the qualitative assessment for its reporting units during its annual impairment review this year to determine if the 2-step quantitative impairment test was necessary. Based on its qualitative assessment, the Company determined that there was no evidence of impairment to the balance of its goodwill. See Note 7: Goodwill and Other Intangible Assets
Other Intangible Assets	Other Intangible Assets Other intangible assets represent purchased assets that lack physical substance but can be distinguished from goodwill because of contractual or other legal rights, or because the asset is capable of being sold or exchanged either separately or in combination with a related contract, asset, or liability. Other intangible assets with finite useful lives are amortized to non-interest expense over their estimated useful lives and are evaluated for impairment whenever events occur or circumstances change indicating the carrying amount of the asset may not be recoverable. Core deposit and customer relationship intangible assets are amortized over their estimated useful lives. See Note 7: Goodwill and Other Intangible Assets
Cash Surrender Value of Life Insurance	Cash Surrender Value of Life InsuranceInvestment in life insurance represents the cash surrender value of life insurance policies on certain current and former officers of Webster. Cash surrender value increases are recorded in non-interest income, decreases are the result of collection on the policies, with death benefit proceeds in excess of cash surrender value recorded in other non-interest income upon the death of an insured.
Securities Sold Under Agreements to Repurchase	Securities Sold Under Agreements to Repurchase These agreements are accounted for as secured financing transactions since Webster maintains effective control over the transferred investment securities and the transfer meets the other criteria for such accounting. Obligations to repurchase the sold investment securities are reflected as a liability in the accompanying Consolidated Balance Sheets. The investment securities underlying the agreements are delivered to a custodial account for the benefit of the dealer or bank with whom each transaction is executed. The dealers or banks, which may sell, loan, or otherwise hypothecate such securities to other parties in the normal course of their operations, agree to resell to Webster the same securities at the maturity date of the agreements. The investment securities underlying the agreements with Bank customers are pledged; however, the customer does not have ability to hypothecate the underlying securities. See Note 10: Borrowings
Share-based Compensation	Share-Based Compensation Webster maintains stock compensation plans under which restricted stock, restricted stock units, non-qualified stock options, incentive stock options, or stock appreciation rights may be granted to employees and directors. Share awards are issued from available treasury shares. Share-based compensation cost is recognized over the vesting period, is based on the grant-date fair value, net of a reduction for estimated forfeitures which is adjusted for actual forfeitures as they occur, and is reported as a component of compensation and benefits expense. Awards are generally subject to a 3 -year vesting period, while certain conditions provide for a 1 -year vesting period. Excess tax benefits result when tax return deductions exceed recognized compensation cost determined using the grant-date fair value approach for financial statement purposes. For restricted stock and restricted stock unit awards, fair value is measured using the Company's common stock closing price at the date of grant. For certain performance-based restricted stock awards, fair value is measured using the Monte Carlo valuation methodology, which provides for the 3 -year performance period. Awards ultimately vest in a range from zero to 150% of the target number of shares under the grant. Compensation expense is subject to adjustment based on management's assessment of Webster's return on equity performance relative to the target number of shares condition. Stock option awards use the Black-Scholes Option-Pricing Model to measure fair value at the date of grant. Dividends are paid on the time-based shares upon grant and are non-forfeitable, while dividends are accrued on the performance-based awards and paid on earned shares when the performance target is met. See Note 18: Share-Based Plans
Income Taxes	Income Taxes Income tax expense, or benefit, is comprised of two components, current and deferred. The current component reflects taxes payable or refundable for a current period based on applicable tax laws, and the deferred component represents the tax effects of temporary differences between amounts recognized for financial accounting and tax purposes. Deferred tax assets and liabilities reflect the tax effects of such differences that are anticipated to result in taxable or deductible amounts in the future, when the temporary differences reverse. DTAs are recognized if it is more likely than not they will be realized, and may be reduced by a valuation allowance if it is more likely than not that all or some portion will not be realized. Tax positions that are uncertain but meet a more likely than not recognition threshold are initially and subsequently measured as the largest amount of tax benefit that has a greater than 50% likelihood of being realized upon settlement with a taxing authority that has full knowledge of all relevant information. The determination of whether or not a tax position meets the more likely than not recognition threshold considers the facts, circumstances, and information available at the reporting date and is subject to management's judgment. Webster recognizes interest expense and penalties on uncertain tax positions as a component of income tax expense and recognizes interest income on refundable income taxes as a component of other non-interest income. See Note 8: Income Taxes
Earnings Per Common Share	Earnings Per Common Share Earnings per common share is computed under the two-class method. Basic earnings per common share is computed by dividing earnings allocated to common shareholders by the weighted-average number of common shares outstanding during the applicable period, excluding outstanding non-participating securities. Certain non-vested restricted stock awards are participating securities as they have non-forfeitable rights to dividends or dividend equivalents. Diluted earnings per common share is computed using the weighted-average number of shares determined for the basic earnings per common share computation plus the dilutive effect of stock compensation and warrants for common stock using the treasury stock method. A reconciliation of the weighted-average shares used in calculating basic earnings per common share and the weighted-average common shares used in calculating diluted earnings per common share is provided in Note 14: Earnings Per Common Share
Comprehensive Income	Comprehensive Income Comprehensive income includes all changes in shareholders’ equity during a period, except those resulting from transactions with shareholders. Comprehensive income consists of net income, and the after-tax effect of the following items: changes in net unrealized gain/loss on securities available for sale, changes in net unrealized gain/loss on derivative instruments, and changes in net actuarial gain/loss and prior service cost for defined benefit pension and other postretirement benefit plans. Comprehensive income is reported in the accompanying Consolidated Statements of Shareholders' Equity, Consolidated Statements of Comprehensive Income, and Note 12: Accumulated Other Comprehensive Loss, Net of Tax
Derivative Instruments and Hedging Activities	Derivative Instruments and Hedging Activities Derivatives are recognized as assets and liabilities in the accompanying Consolidated Balance Sheets and measured at fair value. For exchange-traded contracts, fair value is based on quoted market prices. For non-exchange traded contracts, fair value is based on dealer quotes, pricing models, discounted cash flow methodologies, or similar techniques for which the determination of fair value may require management judgment or estimation, relating to future rates and credit activities. Interest Rate Swap Agreements. For asset/liability management purposes, the Company may use interest rate swaps or interest rate caps to hedge various exposures or to modify interest rate characteristics of various balance sheet accounts. Interest rate swaps are contracts in which a series of interest rate flows are exchanged over a prescribed period of time. The notional amount on which the interest payments are based is not exchanged. Swap agreements entered into for hedge purposes are derivative instruments and generally convert a portion of the Company’s variable-rate debt to a fixed-rate (cash flow hedge), or convert a portion of its fixed-rate debt to a variable-rate (fair value hedge). Webster uses forward-settle interest rate swaps to protect the Company against adverse fluctuations in interest rates by reducing its exposure to variability in cash flows relating to interest payments on forecasted debt issuances. Forward-settle swaps typically have a future effective date that coincides with the expected debt issuance date. The forward-settle swaps are typically terminated and cash settled upon hedge debt issuance date. The gain or loss on a derivative designated and qualifying as a fair value hedging instrument, as well as the offsetting gain or loss on the hedged item attributable to the risk being hedged, is recognized currently in earnings in the same accounting period. The effective portion of the gain or loss on a derivative designated and qualifying as a cash flow hedging instrument is initially reported as a component of AOCL and subsequently reclassified into earnings in the same period or periods during which the hedged transaction affects earnings. The ineffective portion of the gain or loss on the derivative instrument, if any, is recognized in non-interest income. Interest rate derivative financial instruments receive hedge accounting treatment only if they are qualified and properly designated as hedges and are expected to be, and are, effective in substantially reducing interest rate risk arising from specifically identified assets and liabilities. A hedging instrument is expected at inception to be highly effective at offsetting changes in the hedged transactions attributable to the changes in the hedged risk. The Company expects that the hedging relationship will be highly effective; however, it does not assume there is no ineffectiveness. The Company performs quarterly prospective and retrospective assessments of the hedge effectiveness to ensure the hedging relationship continues to be highly effective and that hedge accounting can continue to be applied. Those derivative financial instruments that do not meet specified hedging criteria are recorded at fair value with changes in fair value recorded in income. Cash flows from derivative financial instruments designated for hedge accounting are classified in the cash flow statement in the same category as the cash flows of the asset or liability being hedged. Derivative Loan Commitments. Mortgage loan commitments related to the origination of mortgages that will be held for sale upon funding are considered derivative instruments. Loan commitments that are derivatives are recognized at fair value on the Consolidated Balance Sheets in other assets and other liabilities with changes in their fair values recorded in non-interest income. Counterparty Credit Risk. The Company's exposure from bilateral, non-cleared derivatives is collateralized and subject to daily margin call settlements. Credit exposure related to non-cleared derivatives may be offset by the amount of collateral pledged by the counterparty. The Company's credit exposure on interest rate swaps consists of the net favorable value plus interest payments of all swaps by each of the counterparties. Cleared derivative transactions are with our selected clearing exchange, Chicago Mercantile Exchange (CME). Exposure is settled to market on a daily basis, with additional credit exposure related to initial margin collateral pledged to CME at trade execution. Institutional counterparties are underwritten and approved through the Company’s independent credit approval process. The Company evaluates the credit risk of its counterparties, taking into account such factors as the likelihood of default, its net exposures, and remaining contractual life, among other things, in determining if any adjustments related to credit risk are required. See Note 15: Derivative Financial Instruments
Offsetting Assets and Liabilities	Offsetting Assets and Liabilities .
Fair Value Measurements	Fair Value Measurements The Company measures many of its assets and liabilities on a fair value basis, in accordance with ASC Topic 820, " Fair Value Measurement. " Fair value is used on a recurring basis for certain assets and liabilities in which fair value is the primary basis of accounting. Examples of these include derivative instruments, available-for-sale securities and loans held for sale where the Company has elected the fair value option. Additionally, fair value is used on a non-recurring basis to evaluate assets or liabilities for impairment. Examples of these include impaired loans and leases, mortgage servicing assets, long-lived assets, goodwill, and loans not originated for sale but subsequently transferred to held for sale, which are accounted for at the lower of cost or fair value. Further information regarding the Company's policies and methodology used to measure fair value is presented in Note 16: Fair Value Measurements
Employee Retirement Benefit Plan	Employee Retirement Benefit Plan Webster Bank maintains a noncontributory defined benefit pension plan covering all employees that were participants on or before December 31, 2007. Costs related to this qualified plan, based upon actuarial computations of current and future benefits for eligible employees, are charged to non-interest expense and are funded in accordance with the requirements of the Employee Retirement Income Security Act. The plan is recorded as an asset if overfunded or a liability if underfunded. There is a supplemental retirement plan for select executive level employees that were participants on or before December 31, 2007. There is also a postretirement healthcare benefits plan for certain retired employees.
Marketing Costs	Marketing CostsMarketing costs are expensed as incurred over the projected benefit period.
Recently Adopted and Issued Accounting Standards Updates	Recently Adopted Accounting Standards Updates Effective January 1, 2018 , the following new accounting guidance was adopted by the Company: ASU No. 2017-08, Receivables - Nonrefundable Fees and Other Costs (Subtopic 310-20) - Premium Amortization on Purchased Callable Debt Securities. The Update shortens the amortization period for certain investments in callable debt securities purchased at a premium by requiring that the premium be amortized to the earliest call date. Prior to adoption, the Company amortized the premium as a yield adjustment over the contractual life of such debt securities held within the portfolio. The Update accelerates the Company's recognition of premium amortization on those debt securities. The Company adopted the Update during the first quarter of 2018 on a modified retrospective basis. As a result, the Company recorded a $2.8 million cumulative-effect adjustment directly to retained earnings as of January 1, 2018. ASU No. 2017-07, Compensation - Retirement Benefits (Topic 715) - Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost. The Update requires the Company to retrospectively report service cost as a part of compensation expense and the other components of net periodic benefit cost separately from service cost in the Company's consolidated financial statements. The Company previously included all components of net periodic benefit cost as a component of compensation and benefits expense. Upon adoption, only service cost remains in compensation and benefits expense, while the interest cost on benefit obligations, expected return on plan assets, amortization of prior service cost, and recognized net loss components of the net periodic benefit cost are included in other expense. The Company adopted the Update during the first quarter of 2018 on a retrospective basis. As a result, the Company reclassified, for prior periods, the components of it's net periodic benefit costs other than the service cost component from compensation and benefits to other expense in the accompanying Condensed Consolidated Statements of Income. The adoption of this guidance did not have a material impact on the Company's consolidated financial statements. ASU No. 2016-15, Statement of Cash Flows (Topic 230) - Classification of Certain Cash Receipts and Cash Payments. The Update addresses the following eight specific cash flow issues, with the objective of reducing the existing diversity in practice: debt prepayment or debt extinguishment costs; settlement of zero-coupon debt instruments or other debt instruments with coupon interest rates that are insignificant in relation to the effective interest rate of the borrowing; contingent consideration payments made after a business combination; proceeds from the settlement of insurance claims; proceeds from the settlement of corporate-owned life insurance policies, including bank-owned life insurance policies; distributions received from equity method investees; beneficial interests in securitization transactions; and separately identifiable cash flows and application of the predominance principle. The Company adopted the Update during the first quarter of 2018 on a retrospective basis. The adoption of this guidance did not have a material impact on the Company's consolidated financial statements. ASU No. 2016-01, Financial Instruments - Overall (Subtopic 825-10) - Recognition and Measurement of Financial Assets and Financial Liabilities, and ASU No. 2018-03, Technical Corrections and Improvements to Financial Instruments - Overall (Subtopic 825-10) - Recognition and Measurement of Financial Assets and Financial Liabilities. The Updates included targeted amendments in connection with the recognition, measurement, presentation, and disclosure of financial instruments. The main provisions require investments in equity securities to be measured at fair value through net income, unless they qualify for a practical expedient, and require fair value changes arising from changes in instrument-specific credit risk for financial liabilities that are measured under the fair value option to be recognized in other comprehensive income. The provisions also emphasized the existing requirement to use exit prices to measure fair value for disclosure purposes. The Company adopted the Updates during the first quarter of 2018 primarily on a modified retrospective basis. As a result, the Company recorded a benefit of $1.4 million for a cumulative-effect adjustment directly to retained earnings as of January 1, 2018, due to a change in valuation method, from cost less impairment, to net asset value using the practical expedient. Also, the measurement alternative has been elected for equity securities, existing as of January 1, 2018, without readily determinable fair values on a prospective basis. ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606) and subsequent ASUs issued to clarify this Topic. The Update, and subsequent related updates, establish a single comprehensive model for entities to use in accounting for revenue arising from contracts with customers and supersedes most previous revenue recognition guidance, including industry-specific guidance. The Updates are intended to increase comparability across industries. The core principle of the revenue model is that a company will recognize revenue when it transfers control of goods or services to customers, at an amount that reflects the consideration to which it expects to be entitled in exchange for those goods or services. The Company adopted the Updates during the first quarter of 2018 on a modified retrospective transition approach. The Company did not identify any material changes to the timing of revenue recognition. The Company changed how it presents certain recurring revenue streams associated with wealth and investment services as other income, versus a contra expense. The adoption of this guidance did not have a material impact on the Company's financial condition or results of operations, and there was no cumulative effect adjustment to opening retained earnings as no material changes were identified in the timing of revenue recognition, however, additional disclosure has been incorporated in Note 20: Revenue from Contracts with Customers . Accounting Standards Issued but not yet Adopted The following list identifies ASUs applicable to the Company that have been issued by the FASB but are not yet effective: ASU No. 2018-16, Derivatives and Hedging (Topic 815) - Inclusion of the Secured Overnight Financing Rate (SOFR) Overnight Index Swap (OIS) Rate as a Benchmark Interest Rate for Hedge Accounting Purposes The Update permits the use of the OIS rate based on SOFR as a U.S. benchmark interest rate for hedge accounting purposes under Topic 815 in addition to the interest rates on direct U.S. Treasury obligations, the LIBOR swap rate, the OIS rate based on the Fed Funds Effective Rate, and the Securities Industry and Financial Markets Association Municipal Swap Rate. The update is effective for the Company on January 1, 2019. The Company does not expect this Update to have a material impact on its consolidated financial statements. ASU No. 2018-15, Intangibles - Goodwill and Other - Internal-Use Software (Subtopic 350-40) - Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract The Update aligns the requirements for capitalizing implementation costs incurred in a hosting arrangement that is a service contract with the requirements for capitalizing implementation costs incurred to develop or obtain internal-use software. The updated guidance also requires an entity to amortize the capitalized implementation costs as an expense over the term of the hosting arrangement and to present in the same income statement line item as the fees associated with the hosting arrangement. This Update is effective for the Company on January 1, 2020. Early adoption is permitted, although the Company does not intend to early adopt. The Company will apply the amendments in this update prospectively to all implementation costs incurred after the date of adoption. The Company does not expect this Update to have a material impact on its consolidated financial statements. ASU No. 2018-14, Compensation-Retirement Benefits - Defined Benefit Plan - General (Subtopic 715-20) - Disclosure Framework - Changes to the Disclosure Requirements for Defined Benefit Plans The Update modifies the disclosure requirements for defined benefit pension plans and other postretirement plans. This updated guidance will be effective for the Company on January 1, 2021. The Company does not expect this Update to have a material impact on its consolidated financial statements. ASU No. 2018-13, Fair Value Measurement (Topic 820) - Disclosure Framework - Changes to the Disclosure Requirements for Fair Value Measurement The Update modifies the disclosure requirements on fair value measurements. The updated guidance will no longer require entities to disclose the amount and reasons for transfers between Level 1 and Level 2 of the fair value hierarchy. However, it will require public companies to disclose changes in unrealized gains and losses for the period included in other comprehensive income for recurring Level 3 fair value measurements held at the end of the reporting period and the range and weighted average of significant unobservable inputs used to develop Level 3 measurements. This Update is effective for the Company on January 1, 2020, and earlier adoption is permitted. The Company does not expect this Update to have a material impact on its consolidated financial statements. ASU No. 2017-12, Derivatives and Hedging (Topic 815) - Targeted Improvements to Accounting for Hedging Activities. The purpose of the Update is to better align the financial reporting for hedging activities with the economic objectives of those activities. The update requires a modified retrospective transition method in which the Company will recognize a cumulative effect of the change on the opening balance for each affected component of equity in the financial statements as of the date of adoption. The Update is effective for the Company on January 1, 2019. The adoption will not have a material impact on the Company's consolidated financial statements. ASU No. 2017-04, Intangibles - Goodwill and Other (Topic 350) - Simplifying the Test for Goodwill Impairment. The Update simplifies quantitative goodwill impairment testing by requiring entities to compare the fair value of a reporting unit with its carrying amount and recognize an impairment charge for any amount by which the carrying amount exceeds the reporting unit’s fair value, to the extent that the loss recognized does not exceed the amount of goodwill allocated to that reporting unit. This changes current guidance by eliminating the second step to the goodwill impairment analysis which involves calculating the implied fair value of goodwill determined in the same manner as the amount of goodwill recognized in a business combination upon acquisition. Entities will still have the option to perform the qualitative assessment for a reporting unit to determine if the quantitative impairment test is necessary. The update must be applied prospectively and is effective for the Company on January 1, 2020. Early adoption is permitted. The Company does not expect the new guidance to have a material impact on its consolidated financial statements. ASU No. 2016-13, Financial Instruments - Credit Losses (Topic 326) - Measurement of Credit Losses on Financial Instruments and subsequent ASUs issued to clarify this Topic. Current GAAP requires an incurred loss methodology for recognizing credit losses. This approach delays recognition until it is probable a loss has been incurred. The main objective of this Update is to provide financial statement users with more decision-useful information about the expected credit losses on financial instruments and other commitments to extend credit held by a reporting entity at each reporting date. To achieve this objective, the amendments in this Update replace the incurred loss impairment methodology in current GAAP with a methodology that reflects expected credit losses and requires consideration of a broader range of reasonable and supportable information to determine credit loss estimates. The change from an incurred loss method to an expected loss method represents a fundamental shift from existing GAAP and may result in a material increase to the Company's accounting for credit losses on financial instruments. To prepare for implementation of the new standard the Company has established a project lead and has empowered a cross functional steering committee comprised of members from different disciplines including Credit, Accounting, Finance and Treasury as well as specific working groups to focus on key components of the development process. Through these working groups, the Company has begun to evaluate the effect that this Update, including the subsequent ASUs issued to clarify this Topic, will have on its financial statements and related disclosures. An implementation project plan has been created and is made up of targeted work streams focused on credit models, data management, treasury, and accounting. These work streams are collectively assessing required resources, use of existing and new models, and data availability. The Company expects that the new credit models will include additional assumptions used to calculate credit losses over the estimated life of the financial assets and will include expected future changes in macroeconomic conditions. The Company contracted with system solution providers and is in the process of implementing the selected solutions. During 2019, the Company will focus on model validations as well as the development of processes and related controls. The Company expects to begin parallel runs by mid-2019. These Updates are effective for the Company on January 1, 2020. The impact of adopting these Updates is expected to be influenced by the composition, characteristics, and credit quality of our loan and securities portfolios as well as the economic conditions in effect at the adoption date. Therefore, we are unable to reasonably estimate the impact of adoption at this time. ASU No. 2016-02, Leases (Topic 842) and subsequent ASUs issued to clarify this Topic. The Update introduces a lessee model that requires substantially all leases to be recorded as assets and liabilities on the balance sheet and will require expanded quantitative and qualitative disclosures regarding key information about leasing arrangements. The lessor model remains substantially the same with targeted improvements that do not materially impact the Company. A new transition method option that would allow the Company to use the effective date, January 1, 2019, as the date of initial application of the new leases standard and recognize a cumulative-effect adjustment to the opening balance of retained earnings in the period of adoption is included by way of a subsequent Update. The Company will elect this transition method and will record an immaterial transition adjustment to beginning retained earnings. The Company has engaged a third party consultant to assist with its implementation efforts including with its review of existing leases, and certain service contracts for embedded leases, to evaluate the impact of these Updates. The review of certain service contracts for embedded leases has not identified leases individually or in aggregate that would have a material impact to the Company's financial statements. The Company will utilize a third-party software solution to assist with the accounting under these updates. Management's implementation of the lease accounting standard is substantially complete. Upon adoption of the standard, the Company expects to recognize a right of use asset of approximately $160 million and a lease liability of approximately $180 million , primarily relating to the Company's real-estate lease portfolio. Securities and Exchange Commission’s Final Rule on Disclosure Update and Simplification The SEC adopted the Final Rule, Disclosure Update and Simplification, that amends certain of the SEC’s disclosure requirements to reduce redundant, duplicative, or outdated disclosures due to changes in U.S. GAAP, International Financial Reporting Standards, or changes in technology or the business environment. Most of the amendments included in the SEC’s Final Rule eliminate certain disclosure requirements. This Final Rule is effective for all filings submitted on or after November 5, 2018. The Company eliminated certain information from Item 5. Market For Registrant's Common Equity, Related Stockholder Matters, And Issuer Purchases Of Equity Securities, contained elsewhere in this report.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Property, Plant and Equipment	Premises and equipment are carried at cost, less accumulated depreciation. Depreciation of premises and equipment is computed on a straight-line basis over the estimated useful lives of the assets, as follows: Minimum Maximum Building and Improvements 5 - 40 years Leasehold improvements 5 - 20 years (or term or lease, if shorter) Fixtures and equipment 5 - 10 years Data processing and software 3 - 7 years At December 31, (In thousands) 2018 2017 Land $ 10,997 $ 11,302 Buildings and improvements 79,619 80,646 Leasehold improvements 77,669 82,067 Fixtures and equipment 75,219 76,665 Data processing and software 252,723 234,667 Total premises and equipment 496,227 485,347 Less: Accumulated depreciation and amortization (371,377 ) (355,346 ) Premises and equipment, net $ 124,850 $ 130,001 Depreciation and amortization of premises and equipment was $34.9 million , $33.1 million , and $30.8 million for the years ended December 31, 2018 , 2017 , and 2016

Investment Securities (Tables)

Investment Securities (Tables)	12 Months Ended
	Dec. 31, 2018
Investments, Debt and Equity Securities [Abstract]
Summary of Investment Securities	A Summary of the amortized cost and fair value of investment securities is presented below: At December 31, 2018 2017 (In thousands) Amortized Cost Unrealized Gains Unrealized Losses Fair Value Amortized Cost Unrealized Gains Unrealized Losses Fair Value Available-for-sale: U.S. Treasury Bills $ 7,549 $ 1 $ — $ 7,550 $ 1,247 $ — $ — $ 1,247 Agency CMO 238,968 412 (4,457 ) 234,923 308,989 1,158 (3,814 ) 306,333 Agency MBS 1,521,534 1,631 (42,076 ) 1,481,089 1,124,960 2,151 (19,270 ) 1,107,841 Agency CMBS 608,167 — (41,930 ) 566,237 608,276 — (20,250 ) 588,026 CMBS 447,897 645 (2,961 ) 445,581 358,984 2,157 (74 ) 361,067 CLO 114,641 94 (1,964 ) 112,771 209,075 910 (134 ) 209,851 Single issuer-trust preferred — — — — 7,096 — (46 ) 7,050 Corporate debt 55,860 — (5,281 ) 50,579 56,504 797 (679 ) 56,622 Total available-for-sale $ 2,994,616 $ 2,783 $ (98,669 ) $ 2,898,730 $ 2,675,131 $ 7,173 $ (44,267 ) $ 2,638,037 Held-to-maturity: Agency CMO $ 208,113 $ 287 $ (5,255 ) $ 203,145 $ 260,114 $ 664 $ (4,824 ) $ 255,954 Agency MBS 2,517,823 8,250 (79,701 ) 2,446,372 2,569,735 16,989 (37,442 ) 2,549,282 Agency CMBS 667,500 53 (22,572 ) 644,981 696,566 — (10,011 ) 686,555 Municipal bonds and notes 715,041 2,907 (18,285 ) 699,663 711,381 8,584 (6,558 ) 713,407 CMBS 216,943 405 (2,388 ) 214,960 249,273 2,175 (620 ) 250,828 Private Label MBS — — — — 323 1 — 324 Total held-to-maturity $ 4,325,420 $ 11,902 $ (128,201 ) $ 4,209,121 $ 4,487,392 $ 28,413 $ (59,455 ) $ 4,456,350
Other than Temporary Impairment, Credit Losses Recognized in Earnings	The following table presents the changes in OTTI: Years ended December 31, (In thousands) 2018 2017 2016 Beginning balance $ 1,364 $ 3,243 $ 3,288 Reduction for investment securities called (542 ) (2,005 ) (194 ) Additions for OTTI not previously recognized in earnings — 126 149 Ending balance $ 822 $ 1,364 $ 3,243
Summary of Gross Unrealized Losses not Considered OTTI	The following tables provide information on fair value and unrealized losses for the individual investment securities with an unrealized loss, aggregated by classification and length of time that the individual investment securities have been in a continuous unrealized loss position: At December 31, 2018 Less Than Twelve Months Twelve Months or Longer Total (Dollars in thousands) Fair Value Unrealized Losses Fair Value Unrealized Losses # of Holdings Fair Value Unrealized Losses Available-for-sale: Agency CMO $ 15,524 $ (72 ) $ 180,641 $ (4,385 ) 36 $ 196,165 $ (4,457 ) Agency MBS 321,678 (2,078 ) 975,084 (39,998 ) 184 1,296,762 (42,076 ) Agency CMBS — — 566,237 (41,930 ) 37 566,237 (41,930 ) CMBS 343,457 (2,937 ) 5,193 (24 ) 39 348,650 (2,961 ) CLO 83,305 (1,695 ) 14,873 (269 ) 5 98,178 (1,964 ) Single issuer-trust preferred — — — — — — — Corporate debt 35,990 (1,820 ) 14,589 (3,461 ) 8 50,579 (5,281 ) Total available-for-sale in an unrealized loss position $ 799,954 $ (8,602 ) $ 1,756,617 $ (90,067 ) 309 $ 2,556,571 $ (98,669 ) Held-to-maturity: Agency CMO $ 691 $ (1 ) $ 182,396 $ (5,254 ) 25 $ 183,087 $ (5,255 ) Agency MBS 288,635 (1,916 ) 1,892,951 (77,785 ) 272 2,181,586 (79,701 ) Agency CMBS — — 635,284 (22,572 ) 56 635,284 (22,572 ) Municipal bonds and notes 68,351 (882 ) 414,776 (17,403 ) 223 483,127 (18,285 ) CMBS 24,881 (270 ) 132,464 (2,118 ) 20 157,345 (2,388 ) Total held-to-maturity in an unrealized loss position $ 382,558 $ (3,069 ) $ 3,257,871 $ (125,132 ) 596 $ 3,640,429 $ (128,201 ) At December 31, 2017 Less Than Twelve Months Twelve Months or Longer Total (Dollars in thousands) Fair Value Unrealized Losses Fair Value Unrealized Losses # of Holdings Fair Value Unrealized Losses Available-for-sale: Agency CMO $ 81,001 $ (449 ) $ 119,104 $ (3,365 ) 27 $ 200,105 $ (3,814 ) Agency MBS 416,995 (2,920 ) 606,021 (16,350 ) 135 1,023,016 (19,270 ) Agency CMBS 54,182 (851 ) 533,844 (19,399 ) 36 588,026 (20,250 ) CMBS 23,869 (74 ) — — 6 23,869 (74 ) CLO 56,335 (134 ) — — 3 56,335 (134 ) Single issuer-trust preferred 7,050 (46 ) — — 1 7,050 (46 ) Corporate debt 11,082 (395 ) 6,265 (284 ) 4 17,347 (679 ) Total available-for-sale in an unrealized loss position $ 650,514 $ (4,869 ) $ 1,265,234 $ (39,398 ) 212 $ 1,915,748 $ (44,267 ) Held-to-maturity: Agency CMO $ 98,090 $ (1,082 ) $ 106,775 $ (3,742 ) 22 $ 204,865 $ (4,824 ) Agency MBS 762,107 (4,555 ) 1,197,839 (32,887 ) 205 1,959,946 (37,442 ) Agency CMBS 576,770 (7,599 ) 109,785 (2,412 ) 56 686,555 (10,011 ) Municipal bonds and notes 6,432 (38 ) 226,861 (6,520 ) 92 233,293 (6,558 ) CMBS 92,670 (413 ) 14,115 (207 ) 13 106,785 (620 ) Total held-to-maturity in an unrealized loss position $ 1,536,069 $ (13,687 ) $ 1,655,375 $ (45,768 ) 388 $ 3,191,444 $ (59,455 )
Summary of Sale Proceeds of Available for Sale Securities	Sales of Available-for Sale Securities There were no sales during the years ended December 31, 2018 and 2017 . For the year ended December 31, 2016 , proceeds from sales were $259.3 million , with gross realized gains of $2.9 million less gross realized losses of $2.5 million resulting in a gain on sale of investment securities, net of $0.4 million .
Summary of Debt Securities by Contractual Maturity	The amortized cost and fair value of debt securities by contractual maturity are set forth below: At December 31, 2018 Available-for-Sale Held-to-Maturity (In thousands) Amortized Cost Fair Value Amortized Cost Fair Value Due in one year or less $ 27,880 $ 27,865 $ 7,047 $ 7,059 Due after one year through five years 17,126 17,155 7,909 8,019 Due after five through ten years 275,969 274,027 31,455 31,500 Due after ten years 2,673,641 2,579,683 4,279,009 4,162,543 Total debt securities $ 2,994,616 $ 2,898,730 $ 4,325,420 $ 4,209,121

Loans and Leases (Tables)

Loans and Leases (Tables)	12 Months Ended
	Dec. 31, 2018
Loans and Leases Receivable Disclosure [Abstract]
Schedule of Accounts, Notes, Loans and Financing Receivable	The following table summarizes loans and leases: At December 31, (In thousands) 2018 2017 Residential $ 4,416,637 $ 4,490,878 Consumer 2,396,704 2,590,225 Commercial 6,216,606 5,368,694 Commercial Real Estate 4,927,145 4,523,828 Equipment Financing 508,397 550,233 Loans and leases (1) (2) $ 18,465,489 $ 17,523,858 (1) Loans and leases include net deferred fees and net premiums and discounts of $13.9 million and $20.6 million at December 31, 2018 and December 31, 2017 , respectively. (2) At December 31, 2018 , the Company had pledged $7.1 billion of eligible loans as collateral to support borrowing capacity at the FHLB of Boston and the FRB of Boston.
Past Due Financing Receivables	The following tables summarize the aging of loans and leases: At December 31, 2018 (In thousands) 30-59 Days Past Due and Accruing 60-89 Days 90 or More Days Past Due and Accruing Non-accrual Total Past Due and Non-accrual Current Total Loans and Leases Residential $ 8,513 $ 4,301 $ — $ 49,188 $ 62,002 $ 4,354,635 $ 4,416,637 Consumer: Home equity 9,250 5,385 — 33,495 48,130 2,121,049 2,169,179 Other consumer 1,774 957 — 1,494 4,225 223,300 227,525 Commercial: Commercial non-mortgage 1,011 702 104 55,810 57,627 5,189,808 5,247,435 Asset-based — — — 224 224 968,947 969,171 Commercial real estate: Commercial real estate 1,275 245 — 8,242 9,762 4,698,552 4,708,314 Commercial construction — — — — — 218,831 218,831 Equipment financing 510 405 — 6,314 7,229 501,168 508,397 Total $ 22,333 $ 11,995 $ 104 $ 154,767 $ 189,199 $ 18,276,290 $ 18,465,489 At December 31, 2017 (In thousands) 30-59 Days Past Due and Accruing 60-89 Days 90 or More Days Past Due and Accruing Non-accrual Total Past Due and Non-accrual Current Total Loans and Leases Residential $ 8,643 $ 5,146 $ — $ 44,481 $ 58,270 $ 4,432,608 $ 4,490,878 Consumer: Home equity 12,668 5,770 — 35,645 54,083 2,298,185 2,352,268 Other consumer 2,556 1,444 — 1,707 5,707 232,250 237,957 Commercial: Commercial non-mortgage 5,212 603 644 39,214 45,673 4,488,242 4,533,915 Asset-based — — — 589 589 834,190 834,779 Commercial real estate: Commercial real estate 478 77 248 4,484 5,287 4,238,987 4,244,274 Commercial construction — — — — — 279,554 279,554 Equipment financing 1,732 626 — 393 2,751 547,482 550,233 Total $ 31,289 $ 13,666 $ 892 $ 126,513 $ 172,360 $ 17,351,498 $ 17,523,858
Activity In Allowance For Losses	The following tables summarize the activity in, as well as the loan and lease balances that were evaluated for, the ALLL: At or for the Year ended December 31, 2018 (In thousands) Residential Consumer Commercial Commercial Real Estate Equipment Financing Total Allowance for loan and lease losses: Balance at January 1, 2018 $ 19,058 $ 36,190 $ 89,533 $ 49,407 $ 5,806 $ 199,994 Provision (benefit) charged to expense 2,016 4,628 23,041 12,644 (329 ) 42,000 Losses charged off (3,455 ) (19,228 ) (18,220 ) (2,061 ) (423 ) (43,387 ) Recoveries 1,980 7,091 4,439 161 75 13,746 Balance at December 31, 2018 $ 19,599 $ 28,681 $ 98,793 $ 60,151 $ 5,129 $ 212,353 Individually evaluated for impairment $ 4,286 $ 1,383 $ 7,824 $ 1,661 $ 196 $ 15,350 Collectively evaluated for impairment $ 15,313 $ 27,298 $ 90,969 $ 58,490 $ 4,933 $ 197,003 Loan and lease balances: Individually evaluated for impairment $ 103,531 $ 39,144 $ 99,512 $ 10,828 $ 6,315 $ 259,330 Collectively evaluated for impairment 4,313,106 2,357,560 6,117,094 4,916,317 502,082 18,206,159 Loans and leases $ 4,416,637 $ 2,396,704 $ 6,216,606 $ 4,927,145 $ 508,397 $ 18,465,489 At or for the Year ended December 31, 2017 (In thousands) Residential Consumer Commercial Commercial Real Estate Equipment Financing Total Allowance for loan and lease losses: Balance at January 1, 2017 $ 23,226 $ 45,233 $ 71,905 $ 47,477 $ 6,479 $ 194,320 Provision (benefit) charged to expense (2,692 ) 9,367 23,417 11,040 (232 ) 40,900 Losses charged off (2,500 ) (24,447 ) (8,147 ) (9,275 ) (558 ) (44,927 ) Recoveries 1,024 6,037 2,358 165 117 9,701 Balance at December 31, 2017 $ 19,058 $ 36,190 $ 89,533 $ 49,407 $ 5,806 $ 199,994 Individually evaluated for impairment $ 4,805 $ 1,668 $ 9,786 $ 272 $ 23 $ 16,554 Collectively evaluated for impairment $ 14,253 $ 34,522 $ 79,747 $ 49,135 $ 5,783 $ 183,440 Loan and lease balances: Individually evaluated for impairment $ 114,295 $ 45,436 $ 72,471 $ 11,226 $ 3,325 $ 246,753 Collectively evaluated for impairment 4,376,583 2,544,789 5,296,223 4,512,602 546,908 17,277,105 Loans and leases $ 4,490,878 $ 2,590,225 $ 5,368,694 $ 4,523,828 $ 550,233 $ 17,523,858 At or for the Year ended December 31, 2016 (In thousands) Residential Consumer Commercial Commercial Real Estate Equipment Financing Total Allowance for loan and lease losses: Balance at January 1, 2016 $ 25,876 $ 42,052 $ 59,977 $ 41,598 $ 5,487 $ 174,990 Provision (benefit) charged to expense 230 18,507 28,662 7,930 1,021 56,350 Losses charged off (4,636 ) (20,669 ) (18,360 ) (2,682 ) (565 ) (46,912 ) Recoveries 1,756 5,343 1,626 631 536 9,892 Balance at December 31, 2016 $ 23,226 $ 45,233 $ 71,905 $ 47,477 $ 6,479 $ 194,320 Individually evaluated for impairment $ 8,090 $ 2,903 $ 7,422 $ 169 $ 9 $ 18,593 Collectively evaluated for impairment $ 15,136 $ 42,330 $ 64,483 $ 47,308 $ 6,470 $ 175,727 Loan and lease balances: Individually evaluated for impairment $ 119,424 $ 45,719 $ 53,037 $ 24,755 $ 6,420 $ 249,355 Collectively evaluated for impairment 4,135,258 2,638,781 4,887,894 4,486,091 629,209 16,777,233 Loans and leases $ 4,254,682 $ 2,684,500 $ 4,940,931 $ 4,510,846 $ 635,629 $ 17,026,588
Impaired Loans	The following tables summarize impaired loans and leases: At December 31, 2018 (In thousands) Unpaid Principal Balance Total Recorded Investment Recorded Investment No Allowance Recorded Investment With Allowance Related Valuation Allowance Residential: 1-4 family $ 113,575 $ 103,531 $ 64,899 $ 38,632 $ 4,286 Consumer home equity 44,654 39,144 30,576 8,568 1,383 Commercial: Commercial non-mortgage 120,165 99,287 65,724 33,563 7,818 Asset-based 550 225 — 225 6 Commercial real estate: Commercial real estate 13,355 10,828 2,125 8,703 1,661 Commercial construction — — — — — Equipment financing 6,368 6,315 2,946 3,369 196 Total $ 298,667 $ 259,330 $ 166,270 $ 93,060 $ 15,350 At December 31, 2017 (In thousands) Unpaid Principal Balance Total Recorded Investment Recorded Investment No Allowance Recorded Investment With Allowance Related Valuation Allowance Residential: 1-4 family $ 125,352 $ 114,295 $ 69,759 $ 44,536 $ 4,805 Consumer home equity 50,809 45,436 34,418 11,018 1,668 Commercial: Commercial non-mortgage 79,900 71,882 27,313 44,569 9,786 Asset based 3,272 589 589 — — Commercial real estate: Commercial real estate 11,994 11,226 6,387 4,839 272 Commercial construction — — — — — Equipment financing 3,409 3,325 2,932 393 23 Total $ 274,736 $ 246,753 $ 141,398 $ 105,355 $ 16,554 The following table summarizes the average recorded investment and interest income recognized for impaired loans and leases: Years ended December 31, 2018 2017 2016 (In thousands) Average Recorded Investment Accrued Interest Income Cash Basis Interest Income Average Recorded Investment Accrued Interest Income Cash Basis Interest Income Average Accrued Cash Basis Interest Income Residential $ 108,913 $ 3,781 $ 1,106 $ 116,859 $ 4,138 $ 1,264 $ 126,936 $ 4,377 $ 1,200 Consumer home equity 42,290 1,158 980 45,578 1,323 1,046 47,072 1,361 985 Commercial Commercial non-mortgage 85,585 3,064 — 62,459 1,095 — 54,708 1,540 — Asset based 407 — — 295 — — — — — Commercial real estate: Commercial real estate 11,027 198 — 17,397 417 — 28,451 511 — Commercial construction — — — 594 12 — 3,574 92 — Equipment financing 4,820 112 — 4,872 207 — 3,421 184 — Total $ 253,042 $ 8,313 $ 2,086 $ 248,054 $ 7,192 $ 2,310 $ 264,162 $ 8,065 $ 2,185
Financing Receivable Credit Quality Indicators	The following table summarizes commercial, commercial real estate and equipment financing loans and leases segregated by risk rating exposure: Commercial Commercial Real Estate Equipment Financing At December 31, At December 31, At December 31, (In thousands) 2018 2017 2018 2017 2018 2017 (1) - (6) Pass $ 5,781,138 $ 5,048,162 $ 4,773,298 $ 4,355,916 $ 494,585 $ 525,105 (7) Special Mention 206,351 104,594 75,338 62,065 1,303 8,022 (8) Substandard 222,405 206,883 78,509 105,847 12,509 17,106 (9) Doubtful 6,712 9,055 — — — — Total $ 6,216,606 $ 5,368,694 $ 4,927,145 $ 4,523,828 $ 508,397 $ 550,233
Troubled Debt Restructurings on Financing Receivables	Troubled Debt Restructurings The following table summarizes information for TDRs: At December 31, (Dollars in thousands) 2018 2017 Accrual status $ 138,479 $ 147,113 Non-accrual status 91,935 74,291 Total recorded investment of TDR $ 230,414 $ 221,404 Specific reserves for TDR included in the balance of ALLL $ 11,930 $ 12,384 Additional funds committed to borrowers in TDR status 3,893 2,736 For years ended December 31, 2018 , 2017 and 2016 , Webster charged off $14.3 million , $3.2 million , and $18.6 million , respectively, for the portion of TDRs deemed to be uncollectible. The following table provides information on the type of concession for loans and leases modified as TDRs: Years ended December 31, 2018 2017 2016 Number of Loans and Leases Post- Modification Recorded Investment (1) Number of Loans and Leases Post- Modification Recorded Investment (1) Number of Loans and Leases Post- Modification Recorded Investment (1) (Dollars in thousands) Residential: Extended Maturity 1 $ 20 16 $ 2,569 17 $ 2,801 Adjusted Interest rates — — 2 335 2 528 Combination Rate and Maturity 9 947 12 1,733 13 1,537 Other (2) 21 3,573 39 6,200 24 4,090 Consumer home equity: Extended Maturity 4 469 12 976 11 484 Adjusted Interest rates — — 1 247 — — Combination Rate and Maturity 6 618 14 3,469 15 1,156 Other (2) 45 2,812 73 4,907 52 3,131 Commercial non mortgage: Extended Maturity 12 823 12 1,233 12 14,883 Adjusted Interest rates — — — — — — Combination Rate and Maturity 15 8,842 18 9,592 2 648 Other (2) 20 41,248 4 6,375 13 1,767 Commercial real estate: Extended Maturity 2 97 — — 3 4,921 Adjusted Interest rates — — — — 1 237 Combination Rate and Maturity 3 1,485 — — 2 335 Other (2) 1 5,111 — — 1 509 Equipment Financing Extended Maturity 4 736 — — 7 6,642 Total 143 $ 66,781 203 $ 37,636 175 $ 43,669 (1) Post-modification balances approximate pre-modification balances. The aggregate amount of charge-offs as a result of the restructurings was not significant. (2) Other includes covenant modifications, forbearance, loans discharged under Chapter 7 bankruptcy, and/or other concessions. The were no significant amounts of loans and leases modified as TDRs within the previous 12 months and for which there was a payment default for the years ended December 31, 2018 , 2017 and 2016 . The recorded investment of TDRs in commercial, commercial real estate, and equipment financing segregated by risk rating exposure is as follows: At December 31, (In thousands) 2018 2017 (1) - (6) Pass $ 13,165 $ 8,268 (7) Special Mention 84 355 (8) Substandard 67,880 53,050 (9) Doubtful 6,610 — Total $ 87,739 $ 61,673

Transfers of Financial Assets (

Transfers of Financial Assets (Tables)	12 Months Ended
	Dec. 31, 2018
Transfers and Servicing [Abstract]
Schedule of Reserve For Loan Repurchases Table	The following table provides a summary of activity in the reserve for loan repurchases: Years ended December 31, (In thousands) 2018 2017 2016 Beginning balance $ 872 $ 790 $ 1,192 (Benefit) provision charged to expense (160 ) 100 (303 ) Repurchased loans and settlements charged off (38 ) (18 ) (99 ) Ending balance $ 674 $ 872 $ 790 Years ended December 31, (In thousands) 2018 2017 2016 Beginning balance $ 2,362 $ 2,287 $ 2,119 Provision 144 75 168 Ending balance $ 2,506 $ 2,362 $ 2,287
Schedule of Loan Sale Activity [Table Text Block]	The following table provides information for mortgage banking activities: Years ended December 31, (In thousands) 2018 2017 2016 Residential mortgage loans held for sale: Proceeds from sale $ 188,025 $ 335,656 $ 438,925 Loans sold with servicing rights retained 166,909 304,788 399,318 Net gain on sale 3,146 6,211 11,629 Ancillary fees 1,544 2,629 3,532 Fair value option adjustment (266 ) 1,097 (526 )
Servicing Asset at Amortized Cost	The following table presents the changes in carrying value for mortgage servicing assets: Years ended December 31, (In thousands) 2018 2017 2016 Beginning balance $ 25,139 $ 24,466 $ 20,698 Additions 4,459 9,249 11,312 Amortization (8,383 ) (8,576 ) (7,544 ) Ending balance $ 21,215 $ 25,139 $ 24,466

Premises and Equipment (Tables)

Premises and Equipment (Tables)	12 Months Ended
	Dec. 31, 2018
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment	Premises and equipment are carried at cost, less accumulated depreciation. Depreciation of premises and equipment is computed on a straight-line basis over the estimated useful lives of the assets, as follows: Minimum Maximum Building and Improvements 5 - 40 years Leasehold improvements 5 - 20 years (or term or lease, if shorter) Fixtures and equipment 5 - 10 years Data processing and software 3 - 7 years At December 31, (In thousands) 2018 2017 Land $ 10,997 $ 11,302 Buildings and improvements 79,619 80,646 Leasehold improvements 77,669 82,067 Fixtures and equipment 75,219 76,665 Data processing and software 252,723 234,667 Total premises and equipment 496,227 485,347 Less: Accumulated depreciation and amortization (371,377 ) (355,346 ) Premises and equipment, net $ 124,850 $ 130,001 Depreciation and amortization of premises and equipment was $34.9 million , $33.1 million , and $30.8 million for the years ended December 31, 2018 , 2017 , and 2016
Disclosure of Long Lived Assets Held-for-sale	The following table provides a summary of activity for assets held for disposition: Years ended December 31, (In thousands) 2018 2017 Beginning balance $ 144 $ 637 Additions 498 2,006 Write-downs (137 ) (529 ) Sales (414 ) (1,970 ) Ending balance $ 91 $ 144

Goodwill and Other Intangible_2

Goodwill and Other Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Finite-Lived Intangible Assets	Goodwill and other intangible assets by reportable segment consisted of the following: At December 31, 2018 2017 (In thousands) Gross Carrying Amount Accumulated Amortization Net Carrying Amount Gross Carrying Amount Accumulated Amortization Net Carrying Amount Goodwill: Community Banking $ 516,560 $ 516,560 HSA Bank 21,813 21,813 Total Goodwill $ 538,373 $ 538,373 Other intangible assets: HSA Bank - Core deposits $ 22,000 $ (10,842 ) $ 11,158 $ 22,000 $ (8,610 ) $ 13,390 HSA Bank - Customer relationships 21,000 (6,394 ) 14,606 21,000 (4,779 ) 16,221 Total Other intangible assets $ 43,000 $ (17,236 ) $ 25,764 $ 43,000 $ (13,389 ) $ 29,611
Schedule Of Expected Amortization Expense, Next Four Years	As of December 31, 2018 , the remaining estimated aggregate future amortization expense for intangible assets is as follows: (In thousands) 2019 $ 3,847 2020 3,847 2021 3,847 2022 3,847 2023 3,847 Thereafter 6,529

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Schedule of Components of Income Tax Expense (Benefit)	Income tax expense reflects the following expense (benefit) components: Years ended December 31, (In thousands) 2018 2017 2016 Current: Federal $ 58,334 $ 96,364 $ 73,194 State and local 13,409 11,061 5,429 Total current 71,743 107,425 78,623 Deferred: Federal 8,508 39,568 12,542 State and local 964 (48,642 ) 5,158 Total deferred 9,472 (9,074 ) 17,700 Total federal 66,842 135,932 85,736 Total state and local 14,373 (37,581 ) 10,587 Income tax expense $ 81,215 $ 98,351 $ 96,323
Schedule of Effective Income Tax Rate Reconciliation	The following table reflects a reconciliation of reported income tax expense to the amount that would result from applying the federal statutory rate of 21.0% in 2018 , and 35.0% in 2017 and 2016 : Years ended December 31, 2018 2017 2016 (Dollars in thousands) Amount Percent Amount Percent Amount Percent Income tax expense at federal statutory rate $ 92,743 21.0 % $ 123,826 35.0 % $ 106,208 35.0 % Reconciliation to reported income tax expense: SALT expense, net of federal 11,354 2.6 8,189 2.3 6,882 2.3 Tax-exempt interest income, net (6,475 ) (1.5 ) (10,826 ) (3.1 ) (8,917 ) (2.9 ) Increase in cash surrender value of life insurance (3,069 ) (0.7 ) (5,120 ) (1.4 ) (5,166 ) (1.7 ) Excess tax benefits, net (4,483 ) (1.0 ) (6,349 ) (1.8 ) — — Non-deductible FDIC deposit insurance premiums 2,215 0.5 — — — — SALT DTA adjustments, net of federal — — (28,724 ) (8.1 ) — — Tax Act impacts, net (10,982 ) (2.5 ) 20,891 5.9 — — Other, net (88 ) — (3,536 ) (1.0 ) (2,684 ) (1.0 ) Income tax expense and effective tax rate $ 81,215 18.4 % $ 98,351 27.8 % $ 96,323 31.7 %
Schedule of Deferred Tax Assets and Liabilities	The following table reflects the significant components of the DTAs, net: At December 31, (In thousands) 2018 2017 Deferred tax assets: Allowance for loan and lease losses $ 54,390 $ 51,203 Net operating loss and credit carry forwards 70,808 71,813 Compensation and employee benefit plans 29,623 25,023 Net unrealized loss on securities available for sale 25,060 9,548 Other 14,388 15,529 Gross deferred tax assets 194,269 173,116 Valuation allowance (38,181 ) (38,292 ) Total deferred tax assets, net of valuation allowance $ 156,088 $ 134,824 Deferred tax liabilities: Equipment financing leases $ 28,140 $ 27,955 Premises and equipment 10,293 472 Loan origination costs, net 9,608 1,018 Goodwill and other intangible assets 6,293 6,364 Mortgage servicing assets 3,604 4,445 Other 1,634 1,940 Gross deferred tax liabilities 59,572 42,194 Deferred tax assets, net $ 96,516 $ 92,630
Summary of Positions for which Significant Change in Unrecognized Tax Benefits is Reasonably Possible	The following table reflects a reconciliation of the beginning and ending balances of unrecognized tax benefits (UTBs): Years ended December 31, (In thousands) 2018 2017 2016 Beginning balance $ 3,595 $ 3,847 $ 5,094 Additions as a result of tax positions taken during the current year 249 584 613 Additions as a result of tax positions taken during prior years 71 7 — Reductions as a result of tax positions taken during prior years (474 ) (61 ) (625 ) Reductions relating to settlements with taxing authorities (97 ) (392 ) (693 ) Reductions as a result of lapse of statute of limitation periods (488 ) (390 ) (542 ) Ending balance $ 2,856 $ 3,595 $ 3,847

Deposits (Tables)

Deposits (Tables)	12 Months Ended
	Dec. 31, 2018
Banking and Thrift [Abstract]
Deposit Liabilities, Type [Table Text Block]	A summary of deposits by type follows: At December 31, (In thousands) 2018 2017 Non-interest-bearing: Demand $ 4,162,446 $ 4,191,496 Interest-bearing: Checking 2,518,472 2,736,952 Health savings accounts 5,740,601 5,038,681 Money market 2,100,084 2,209,492 Savings 4,140,696 4,348,700 Time deposits 3,196,546 2,468,408 Total interest-bearing 17,696,399 16,802,233 Total deposits $ 21,858,845 $ 20,993,729 Time deposits and interest-bearing checking, included in above balances, obtained through brokers $ 869,003 $ 898,157 Time deposits, included in above balance, that exceed the FDIC limit 555,949 561,512 Demand deposit overdrafts reclassified as loan balances 2,245 2,210
Time Deposit Maturities [Table Text Block]	The scheduled maturities of time deposits are as follows: (In thousands) At December 31, 2018 2019 $ 2,381,229 2020 594,754 2021 143,324 2022 47,224 2023 30,015 Thereafter — Total time deposits $ 3,196,546

Borrowings (Tables)

Borrowings (Tables)	12 Months Ended
	Dec. 31, 2018
Debt Disclosure [Abstract]
Schedule of Repurchase Agreements	The following table summarizes securities sold under agreements to repurchase and other borrowings: At December 31, (In thousands) 2018 2017 Total Outstanding Rate Total Outstanding Rate Securities sold under agreements to repurchase: Original maturity of one year or less $ 236,874 0.35 % $ 288,269 0.17 % Original maturity of greater than one year, non-callable — — 300,000 3.10 Total securities sold under agreements to repurchase 236,874 0.35 588,269 1.66 Fed funds purchased 345,000 2.52 55,000 1.37 Securities sold under agreements to repurchase and other borrowings $ 581,874 1.64 $ 643,269 1.64
Federal Home Loan Bank, Advances	The following table provides information for FHLB advances: At December 31, 2018 2017 (Dollars in thousands) Total Outstanding Weighted- Average Contractual Coupon Rate Total Outstanding Weighted- Average Contractual Coupon Rate Maturing within 1 year $ 1,403,026 2.55 % $ 1,150,000 1.48 % After 1 but within 2 years 215,000 1.73 103,026 1.81 After 2 but within 3 years 200,000 3.16 215,000 1.73 After 3 but within 4 years 150 — 200,000 2.06 (1) After 4 but within 5 years 242 2.95 170 — After 5 years 8,390 2.65 8,909 2.65 (1) Federal Home Loan Bank advances $ 1,826,808 2.52 $ 1,677,105 1.61 (1) Aggregate carrying value of assets pledged as collateral $ 6,689,761 $ 6,402,066 Remaining borrowing capacity 2,568,664 2,600,624
Schedule of Long-Term Debt	The following table summarizes long-term debt: At December 31, (Dollars in thousands) 2018 2017 4.375% Senior fixed-rate notes due February 15, 2024 $ 150,000 $ 150,000 Junior subordinated debt Webster Statutory Trust I floating-rate notes due September 17, 2033 (1) 77,320 77,320 Total notes and subordinated debt 227,320 227,320 Discount on senior fixed-rate notes (608 ) (727 ) Debt issuance cost on senior fixed-rate notes (691 ) (826 ) Long-term debt $ 226,021 $ 225,767 (1) The interest rate on Webster Statutory Trust I floating-rate notes, which varies quarterly based on 3-month LIBOR plus 2.95% , was 5.74% at December 31, 2018 and 4.55% at December 31, 2017 .

Shareholders' Equity (Tables)

Shareholders' Equity (Tables)	12 Months Ended
	Dec. 31, 2018
Equity [Abstract]
Schedule of Stock by Class	Share activity during the year ended December 31, 2018 is as follows: Preferred Stock Series F Common Stock Issued Treasury Stock Held Common Stock Outstanding Balance at January 1, 2018 6,000 93,680,291 1,658,526 92,021,765 Restricted share activity — — (182,553 ) 182,553 Stock options exercised — — (182,517 ) 182,517 Common stock repurchased — — 215,000 (215,000 ) Warrant exercise — 6,020 — 6,020 Series F Preferred Stock issuance — — — — Series E Preferred Stock redemption — — — — Balance at December 31, 2018 6,000 93,686,311 1,508,456 92,177,855

Accumulated Other Comprehensi_2

Accumulated Other Comprehensive Loss, Net of Tax (Tables)	12 Months Ended
	Dec. 31, 2018
Equity [Abstract]
Schedule of Other Comprehensive Income (Loss)	The following table summarizes the changes in AOCL by component: (In thousands) Available For Sale Securities Derivative Instruments Defined Benefit Pension and Other Postretirement Benefit Plans Total Balance at December 31, 2015 $ (6,407 ) $ (22,980 ) $ (48,719 ) $ (78,106 ) Other comprehensive (loss) income before reclassifications (8,901 ) 825 (232 ) (8,308 ) Amounts reclassified from accumulated other comprehensive loss (168 ) 5,087 4,502 9,421 Net current-period other comprehensive (loss) income, net of tax (9,069 ) 5,912 4,270 1,113 Balance at December 31, 2016 (15,476 ) (17,068 ) (44,449 ) (76,993 ) Other comprehensive (loss) income before reclassifications (7,590 ) 181 98 (7,311 ) Amounts reclassified from accumulated other comprehensive loss — 4,384 4,037 8,421 Net current-period other comprehensive (loss) income, net of tax (7,590 ) 4,565 4,135 1,110 Balance at Adoption of ASU No. 2018-02, Income Statement - Reporting Comprehensive Income (Topic 220) - Reclassification of Certain Tax Effects from AOCI (4,881 ) (2,513 ) (8,254 ) (15,648 ) Balance at December 31, 2017 (27,947 ) (15,016 ) (48,568 ) (91,531 ) Other comprehensive (loss) income before reclassifications (43,427 ) 208 (7,122 ) (50,341 ) Amounts reclassified from accumulated other comprehensive loss — 5,495 5,725 11,220 Net current-period other comprehensive (loss) income, net of tax (43,427 ) 5,703 (1,397 ) (39,121 ) Balance at December 31, 2018 $ (71,374 ) $ (9,313 ) $ (49,965 ) $ (130,652 )
Schedule of Accumulated Other Comprehensive Income (Loss)	The following table provides information for the items reclassified from AOCL: Years ended December 31, Accumulated Other Comprehensive Loss Components 2018 2017 2016 Associated Line Item in the Consolidated Statements Of Income (In thousands) Available-for-sale securities: Unrealized gains on investments $ — $ — $ 414 Gain on sale of investment securities, net Unrealized losses on investments — — (149 ) Impairment loss recognized in earnings Total before tax — — 265 Tax expense — — (97 ) Income tax expense Net of tax $ — $ — $ 168 Derivative instruments: Cash flow hedges $ (7,425 ) $ (7,160 ) $ (8,020 ) Interest expense Tax benefit 1,930 2,776 2,933 Income tax expense Net of tax $ (5,495 ) $ (4,384 ) $ (5,087 ) Defined benefit pension and other postretirement benefit plans: Amortization of net loss $ (7,708 ) $ (6,612 ) $ (7,126 ) (1) Prior service costs — — (14 ) (1) Total before tax (7,708 ) (6,612 ) (7,140 ) Tax benefit 1,983 2,575 2,638 Income tax expense Net of tax $ (5,725 ) $ (4,037 ) $ (4,502 ) (1) These accumulated other comprehensive income components are included in the computation of net periodic benefit cost (see Note 17: Retirement Benefit Plans for further details). The following tables summarize the items and related tax effects for each component of OCI/OCL, net of tax: Year ended December 31, 2018 (In thousands) Pre-Tax Amount Tax Benefit (Expense) Net of Tax Amount Available-for-sale securities: Net unrealized loss during the period $ (58,792 ) $ 15,365 $ (43,427 ) Reclassification for net gain included in net income — — — Net non-credit other-than-temporary impairment — — — Total available-for-sale securities (58,792 ) 15,365 (43,427 ) Derivative instruments: Net unrealized gain during the period 280 (72 ) 208 Reclassification adjustment for net loss included in net income 7,425 (1,930 ) 5,495 Total derivative instruments 7,705 (2,002 ) 5,703 Defined benefit pension and other postretirement benefit plans: Current year actuarial loss (9,600 ) 2,478 (7,122 ) Reclassification adjustment for amortization of net loss included in net income 7,708 (1,983 ) 5,725 Reclassification adjustment for prior service cost included in net income — — — Total defined benefit pension and postretirement benefit plans (1,892 ) 495 (1,397 ) Other comprehensive loss, net of tax $ (52,979 ) $ 13,858 $ (39,121 ) Year ended December 31, 2017 (In thousands) Pre-Tax Amount Tax Benefit (Expense) Net of Tax Amount Available-for-sale securities: Net unrealized loss during the period $ (12,423 ) $ 4,833 $ (7,590 ) Reclassification for net gain included in net income — — — Net non-credit other-than-temporary impairment — — — Total available-for-sale securities (12,423 ) 4,833 (7,590 ) Derivative instruments: Net unrealized gain during the period 291 (110 ) 181 Reclassification adjustment for net loss included in net income 7,160 (2,776 ) 4,384 Total derivative instruments 7,451 (2,886 ) 4,565 Defined benefit pension and other postretirement benefit plans: Current year actuarial gain 155 (57 ) 98 Reclassification adjustment for amortization of net loss included in net income 6,612 (2,575 ) 4,037 Reclassification adjustment for prior service cost included in net income — — — Total defined benefit pension and postretirement benefit plans 6,767 (2,632 ) 4,135 Other comprehensive income, net of tax $ 1,795 $ (685 ) $ 1,110 Year ended December 31, 2016 (In thousands) Pre-Tax Amount Tax Benefit (Expense) Net of Tax Amount Available-for-sale securities: Net unrealized loss during the period $ (14,113 ) $ 5,212 $ (8,901 ) Reclassification for net gain included in net income (414 ) 152 (262 ) Net non-credit other-than-temporary impairment 149 (55 ) 94 Total available-for-sale securities (14,378 ) 5,309 (9,069 ) Derivative instruments: Net unrealized gain during the period 1,331 (506 ) 825 Reclassification adjustment for net loss included in net income 8,020 (2,933 ) 5,087 Total derivative instruments 9,351 (3,439 ) 5,912 Defined benefit pension and other postretirement benefit plans: Current year actuarial loss (368 ) 136 (232 ) Reclassification adjustment for amortization of net loss included in net income 7,126 (2,633 ) 4,493 Reclassification adjustment for prior service cost included in net income 14 (5 ) 9 Total defined benefit pension and postretirement benefit plans 6,772 (2,502 ) 4,270 Other comprehensive income, net of tax $ 1,745 $ (632 ) $ 1,113

Regulatory Matters (Tables)

Regulatory Matters (Tables)	12 Months Ended
	Dec. 31, 2018
Regulatory Capital Requirements [Abstract]
Information On The Capital Ratios	The following table provides information on the capital ratios for Webster Financial Corporation and Webster Bank: Actual Capital Requirements Adequately Capitalized Well Capitalized (Dollars in thousands) Amount Ratio Amount Ratio Amount Ratio At December 31, 2018 Webster Financial Corporation CET1 risk-based capital $ 2,284,978 11.44 % $ 898,972 4.5 % $ 1,298,514 6.5 % Total risk-based capital 2,722,194 13.63 1,598,172 8.0 1,997,715 10.0 Tier 1 risk-based capital 2,430,015 12.16 1,198,629 6.0 1,598,172 8.0 Tier 1 leverage capital 2,430,015 9.02 1,077,303 4.0 1,346,628 5.0 Webster Bank CET1 risk-based capital $ 2,170,566 10.87 % $ 898,317 4.5 % $ 1,297,569 6.5 % Total risk-based capital 2,385,425 11.95 1,597,008 8.0 1,996,260 10.0 Tier 1 risk-based capital 2,170,566 10.87 1,197,756 6.0 1,597,008 8.0 Tier 1 leverage capital 2,170,566 8.06 1,076,712 4.0 1,345,889 5.0 At December 31, 2017 Webster Financial Corporation CET1 risk-based capital $ 2,093,116 11.14 % $ 845,389 4.5 % $ 1,221,118 6.5 % Total risk-based capital 2,517,848 13.40 1,502,914 8.0 1,878,643 10.0 Tier 1 risk-based capital 2,238,172 11.91 1,127,186 6.0 1,502,914 8.0 Tier 1 leverage capital 2,238,172 8.63 1,036,817 4.0 1,296,021 5.0 Webster Bank CET1 risk-based capital $ 2,114,224 11.26 % $ 844,693 4.5 % $ 1,220,113 6.5 % Total risk-based capital 2,316,580 12.34 1,501,677 8.0 1,877,097 10.0 Tier 1 risk-based capital 2,114,224 11.26 1,126,258 6.0 1,501,677 8.0 Tier 1 leverage capital 2,114,224 8.14 1,038,442 4.0 1,298,052 5.0

Earnings Per Common Share (Tabl

Earnings Per Common Share (Tables)	12 Months Ended
	Dec. 31, 2018
Earnings Per Share [Abstract]
Earnings Per Share Basic And Diluted	Reconciliation of the calculation of basic and diluted earnings per common share follows: Years ended December 31, (In thousands, except per share data) 2018 2017 2016 Earnings for basic and diluted earnings per common share: Net income $ 360,418 $ 255,439 $ 207,127 Less: Preferred stock dividends 7,853 8,184 8,096 Net income available to common shareholders 352,565 247,255 199,031 Less: Earnings applicable to participating securities 862 424 608 Earnings applicable to common shareholders $ 351,703 $ 246,831 $ 198,423 Shares: Weighted-average common shares outstanding - basic 91,930 91,965 91,367 Effect of dilutive securities: Stock options and restricted stock 292 385 461 Warrants 5 6 28 Weighted-average common shares outstanding - diluted 92,227 92,356 91,856 Earnings per common share: Basic $ 3.83 $ 2.68 $ 2.17 Diluted 3.81 2.67 2.16
Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share	Potential common shares excluded from the effect of dilutive securities because they would have been anti-dilutive, are as follows: Years ended December 31, (In thousands) 2018 2017 2016 Stock options (shares with exercise price greater than market price) — — 41 Restricted stock (due to performance conditions on non-participating shares) 47 58 125

Derivative Financial Instrume_2

Derivative Financial Instruments (Tables)	12 Months Ended
	Dec. 31, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Fair Value Of Derivative Financial Instruments Designated As Cash Flow Hedges	The following table presents the notional amounts and fair values of derivative positions: At December 31, 2018 At December 31, 2017 Asset Derivatives Liability Derivatives Asset Derivatives Liability Derivatives (In thousands) Notional Fair Notional Fair Notional Fair Notional Fair Designated as cash flow hedging instruments: Positions subject to a master netting agreement (1) Interest rate derivatives (2) $ 325,000 $ 3,050 $ — $ — $ 325,000 $ 2,770 $ — $ — Not designated as hedging instruments: Positions subject to a master netting agreement (1) Interest rate derivatives (2) 2,767,518 6,570 1,276,109 2,012 2,791,760 5,977 721,048 1,968 Mortgage banking derivatives (3) 13,599 226 17,000 293 28,497 421 39,230 110 Other 11,952 308 43,097 553 7,914 258 30,328 419 Positions not subject to a master netting agreement (4) Interest rate derivatives 1,668,012 35,635 2,367,876 36,017 1,366,299 23,009 2,146,518 25,631 Risk participation agreements 64,974 39 96,296 81 93,713 80 116,882 111 Other 8,506 450 1,208 54 — — 2,073 184 Total not designated as hedging instruments 4,534,561 43,228 3,801,586 39,010 4,288,183 29,745 3,056,079 28,423 Gross derivative instruments, before netting $ 4,859,561 46,278 $ 3,801,586 39,010 $ 4,613,183 32,515 $ 3,056,079 28,423 Less: Legally enforceable master netting agreements 2,495 2,495 2,245 2,245 Less: Cash collateral posted 4,936 — 6,704 — Total derivative instruments, after netting $ 38,847 $ 36,515 $ 23,566 $ 26,178 (1) The Company has elected to report derivative positions subject to a legally enforceable master netting agreement on a net basis, net of cash collateral. Refer to the Offsetting Derivatives section of this footnote for additional information. (2) Balances related to CME are presented as a single unit of account. Notional amounts of interest rate swaps cleared through CME include $1.9 billion and $1.9 billion for asset derivatives and $1.1 billion and $595 million for liability derivatives at December 31, 2018 and 2017 , respectively, with related fair values of approximately zero. (3) Notional amounts include mandatory forward commitments of $17.0 million , while notional amounts do not include approved floating rate commitments of $6.7 million , at December 31, 2018
Interest Rate Swaps And Caps Not Designated For Hedge Accounting	Years ended December 31, (In thousands) 2018 2017 2016 Designated as cash flow hedging instruments: Interest rate derivatives (1) $ 6,557 $ 7,885 $ 9,762 Not designated as hedging instruments: Interest rate derivatives (2) $ 10,376 $ 2,702 $ 8,668 Risk participation agreements (2) 99 242 (361 ) Mortgage banking derivatives (3) (378 ) (2,062 ) 1,553 Other (2) 2,292 (768 ) (67 ) Total not designated as hedging instruments $ 12,389 $ 114 $ 9,793
Offsetting Liabilities	The following table presents the transition from a gross basis to net basis, due to the application of counterparty netting agreements: At December 31, 2018 At December 31, 2017 (In thousands) Gross Amount Relationship Offset Cash Collateral Offset Net Amount Gross Amount Relationship Offset Cash Collateral Offset Net Amount Derivative instrument gains: Hedge accounting $ 3,050 $ 88 $ 567 $ 2,395 $ 2,770 $ 91 $ 2,679 $ — Non-hedge Accounting 6,878 2,407 4,369 102 6,222 2,154 4,025 43 Total assets $ 9,928 $ 2,495 $ 4,936 $ 2,497 $ 8,992 $ 2,245 $ 6,704 $ 43 Derivative instrument losses: Hedge accounting $ — $ — $ — $ — $ — $ — $ — $ — Non-hedge Accounting 2,566 2,495 — 71 2,387 2,245 — 142 Total liabilities $ 2,566 $ 2,495 $ — $ 71 $ 2,387 $ 2,245 $ — $ 142

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2018
Fair Value Disclosures [Abstract]
Fair Value Of Assets And Liabilities Measured On Recurring Basis	Summaries of the fair values of assets and liabilities measured at fair value on a recurring basis are as follows: At December 31, 2018 (In thousands) Level 1 Level 2 Level 3 NAV Total Financial assets held at fair value: U.S. Treasury Bills $ 7,550 $ — $ — $ — $ 7,550 Agency CMO — 234,923 — — 234,923 Agency MBS — 1,481,089 — — 1,481,089 Agency CMBS — 566,237 — — 566,237 CMBS — 445,581 — — 445,581 CLO — 112,771 — — 112,771 Single issuer-trust preferred — — — — — Corporate debt — 50,579 — — 50,579 Total available-for-sale investment securities 7,550 2,891,180 — — 2,898,730 Gross derivative instruments, before netting (1) 758 45,520 — — 46,278 Originated loans held for sale — 7,908 — — 7,908 Investments held in Rabbi Trust 4,307 — — — 4,307 Alternative investments — — — 2,563 2,563 Total financial assets held at fair value $ 12,615 $ 2,944,608 $ — $ 2,563 $ 2,959,786 Financial liabilities held at fair value: Gross derivative instruments, before netting (1) $ 588 $ 38,422 $ — $ — $ 39,010 At December 31, 2017 (In thousands) Level 1 Level 2 Level 3 NAV Total Financial assets held at fair value: U.S. Treasury Bills $ 1,247 $ — $ — $ — $ 1,247 Agency CMO — 306,333 — — 306,333 Agency MBS — 1,107,841 — — 1,107,841 Agency CMBS — 588,026 — — 588,026 CMBS — 361,067 — — 361,067 CLO — 209,851 — — 209,851 Single issuer-trust preferred — 7,050 — — 7,050 Corporate debt — 56,622 — — 56,622 Total available-for-sale investment securities 1,247 2,636,790 — — 2,638,037 Gross derivative instruments, before netting (1) 258 32,257 — — 32,515 Originated loans held for sale — 20,888 — — 20,888 Investments held in Rabbi Trust 4,801 — — — 4,801 Alternative investments — — 7,460 — 7,460 Total financial assets held at fair value $ 6,306 $ 2,689,935 $ 7,460 $ — $ 2,703,701 Financial liabilities held at fair value: Gross derivative instruments, before netting (1) $ 587 $ 27,836 $ — $ — $ 28,423 (1) For information relating to the impact of netting derivative assets and derivative liabilities as well as the impact from offsetting cash collateral paid to the same derivative counterparties see Note 15: Derivative Financial Instruments .
Fair Value Option, Disclosures [Table Text Block]	The following table presents the fair value, unpaid principal balance, and accrual status, of assets accounted for under the fair value option: At December 31, 2018 At December 31, 2017 (In thousands) Fair Value Unpaid Principal Balance Difference Fair Value Unpaid Principal Balance Difference Originated loans held for sale $ 7,908 $ 8,227 $ (319 ) $ 20,888 $ 20,346 $ 542
Summary Of Estimated Fair Values Of Significant Financial Instruments	air value of selected financial instruments and servicing assets amounts are as follows: At December 31, 2018 2017 (In thousands) Carrying Amount Fair Value Carrying Amount Fair Financial Assets: Level 2 Held-to-maturity investment securities $ 4,325,420 $ 4,209,121 $ 4,487,392 $ 4,456,350 Transferred loans held for sale — — — — Level 3 Loans and leases, net 18,253,136 18,155,798 17,323,864 17,211,619 Mortgage servicing assets 21,215 45,478 25,139 45,309 Financial Liabilities: Level 2 Deposit liabilities, other than time deposits $ 18,662,299 $ 18,662,299 $ 18,525,321 $ 18,525,321 Time deposits 3,196,546 3,175,948 2,468,408 2,455,245 Securities sold under agreements to repurchase and other borrowings 581,874 581,874 643,269 644,084 FHLB advances (1) 1,826,808 1,826,381 1,677,105 1,678,070 Long-term debt (1) 226,021 229,306 225,767 234,359 (1) Adjustments to the carrying amount of long-term debt for unamortized discount and debt issuance cost on senior fixed-rate notes are not included for determination of fair value. See Note 10: Borrowings

Retirement Benefit Plans (Table

Retirement Benefit Plans (Tables)	12 Months Ended
	Dec. 31, 2018
Retirement Benefits [Abstract]
Schedule of Defined Benefit Plans Disclosures	The following table sets forth changes in benefit obligation, changes in plan assets, and the funded status of the defined benefit pension and other postretirement benefits at December 31: Pension Plan SERP Other Benefits (In thousands) 2018 2017 2018 2017 2018 2017 Change in benefit obligation: Beginning balance $ 229,318 $ 211,508 $ 13,096 $ 11,806 $ 3,094 $ 3,852 Service cost — 50 — — — — Interest cost 7,212 7,314 103 375 78 92 Actuarial loss (gain) (18,499 ) 18,396 — 1,037 (352 ) (631 ) Benefits paid and administrative expenses (8,518 ) (7,950 ) (11,364 ) (122 ) (208 ) (219 ) Ending balance (1) 209,513 229,318 1,835 13,096 2,612 3,094 Change in plan assets: Beginning balance 216,225 192,922 — — — — Actual return on plan assets (15,735 ) 31,253 — — — — Employer contributions — — 11,364 122 208 219 Benefits paid and administrative expenses (8,518 ) (7,950 ) (11,364 ) (122 ) (208 ) (219 ) Ending balance 191,972 216,225 — — — — Funded status of the plan at year end (2) $ (17,541 ) $ (13,093 ) $ (1,835 ) $ (13,096 ) $ (2,612 ) $ (3,094 )
Schedule of Net Periodic Benefit Cost Not yet Recognized	The components of AOCL related to the defined benefit pension and other postretirement benefits at December 31, 2018 and 2017 are summarized below: Pension Plan SERP Other Benefits (In thousands) 2018 2017 2018 2017 2018 2017 Net actuarial loss (gain) $ 64,523 $ 59,433 $ 453 $ 3,299 $ (368 ) $ (16 ) Prior service cost — — — — — — Total pre-tax amounts included in AOCL 64,523 59,433 453 3,299 (368 ) (16 ) Deferred tax benefit 14,623 13,407 103 744 (83 ) (3 ) Amounts included in accumulated AOCL, net of tax $ 49,900 $ 46,026 $ 350 $ 2,555 $ (285 ) $ (13 )
Schedule of Expected Benefit Payments	Expected future benefit payments for the defined benefit pension and other postretirement benefits are presented below: (In thousands) Pension Plan SERP Other Benefits 2019 $ 8,636 $ 130 $ 331 2020 9,011 133 318 2021 9,740 133 301 2022 10,416 133 283 2023 10,468 131 262 2024-2028 57,158 650 978
Summary of Net Periodic Benefit Cost	The components of the net periodic benefit cost (benefit) for the defined benefit pension and other postretirement benefits were as follows for the years ended December 31: Pension Plan SERP Other Benefits (In thousands) 2018 2017 2016 2018 2017 2016 2018 2017 2016 Service cost $ — $ 50 $ 45 $ — $ — $ — $ — $ — $ — Interest cost on benefit obligations 7,212 7,314 8,441 103 375 389 78 92 125 Expected return on plan assets (12,716 ) (12,296 ) (11,461 ) — — — — — — Amortization of prior service cost — — — — — — — — 14 Recognized net loss 4,862 5,864 6,665 2,846 748 426 — — 35 Net periodic benefit cost (benefit) $ (642 ) $ 932 $ 3,690 $ 2,949 $ 1,123 $ 815 $ 78 $ 92 $ 174
Schedule of Defined Benefit Plan Amounts Recognized in Other Comprehensive Income (Loss)	Changes in funded status related to the defined benefit pension and other postretirement benefits and recognized as a component of OCI in the accompanying Consolidated Statements of Comprehensive Income as follows for the years ended December 31: Pension Plan SERP Other Benefits (In thousands) 2018 2017 2016 2018 2017 2016 2018 2017 2016 Net (gain) loss $ 9,952 $ (561 ) $ (715 ) $ — $ 1,037 $ 1,023 $ (352 ) $ (631 ) $ 60 Amounts reclassified from AOCL (4,862 ) (5,864 ) (6,665 ) (2,846 ) (748 ) (426 ) — — (35 ) Amortization of prior service cost — — — — — — — — (14 ) Total (gain) loss recognized in OCI $ 5,090 $ (6,425 ) $ (7,380 ) $ (2,846 ) $ 289 $ 597 $ (352 ) $ (631 ) $ 11
Schedule of Changes in Fair Value of Plan Assets	A summary of the fair value and hierarchy classification of financial assets of the pension plan is as follows: At December 31, 2018 2017 (In thousands) Level 1 Level 2 Level 3 NAV Total Level 1 Level 2 Level 3 NAV Total Registered investment companies: Exchange traded funds $ 30,641 $ — $ — $ — $ 30,641 $ 37,848 $ — $ — $ — $ 37,848 Cash and cash equivalents 1,695 — — — 1,695 1,115 — — — 1115 Common collective trust funds: Fixed Income funds — — — 107,753 107,753 — 107,430 — — 107,430 Equity Funds — — — 51,883 51,883 — 69,832 — — 69,832 Total $ 32,336 $ — $ — $ 159,636 $ 191,972 $ 38,963 $ 177,262 $ — $ — $ 216,225
Schedule of Effect of Significant Unobservable Inputs, Changes in Plan Assets	The following table sets forth a summary of changes in the fair value of Level 3 assets of the pension plan: Year ended December 31, (In thousands) 2017 Beginning balance $ 793 Employer contributions 78 Unrealized gains relating to instruments still held at the reporting date — Benefit payments, administrative expenses (166 ) Asset sales (705 ) Ending balance $ —
Schedule of Allocation of Plan Assets	The following table presents the target allocation and the pension plan asset allocation for the periods indicated, by asset category: Target Allocation Percentage of Pension Plan assets 2019 2018 2017 Fixed income investments 55 % 56 % 50 % Equity investments 45 43 50 Cash and cash equivalents — % 1 % — % Total 100 % 100 % 100 %
Schedule of Assumptions Used	Weighted-average assumptions used to determine benefit obligations at December 31 are as follows: Pension Plan SERP Other Benefits 2018 2017 2018 2017 2018 2017 Discount rate 4.12 % 3.50 % 3.95 % 3.30 % 3.69 % 3.00 % Rate of compensation increase n/a n/a n/a n/a n/a n/a Weighted-average assumptions used to determine net periodic benefit cost for the years ended December 31 are as follows: Pension Plan SERP Other Benefits 2018 2017 2016 2018 2017 2016 2018 2017 2016 Discount rate 3.50 % 4.01 % 4.20 % 3.30 % 3.63 % 3.75 % 3.00 % 3.27 % 3.35 % Expected long-term return on assets 6.00 % 6.50 % 7.00 % n/a n/a n/a n/a n/a n/a Rate of compensation increase n/a n/a n/a n/a n/a n/a n/a n/a n/a Assumed healthcare cost trend n/a n/a n/a n/a n/a n/a 7.00 % 7.50 % 8.25 %
Schedule of Multiemployer Plans	The following table sets forth contributions and funding status of Webster Bank's portion of this plan: (Dollars in thousands) Contributions by Webster Bank for the year ended December 31, Funded Status of the Plan at December 31, Plan Name Employer Identification Number Plan Number 2018 2017 2016 2018 2017 Pentegra Defined Benefit Plan for Financial Institutions 13-5645888 333 $679 $614 $690 At least 80 percent At least 80 percent

Share-Based Plans (Tables)

Share-Based Plans (Tables)	12 Months Ended
	Dec. 31, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Schedule of Allocation of Stock-based Compensation Expense and Related Tax Benefit	The following table provides a summary of stock compensation expense and income tax benefit associated with stock compensation recognized in the accompanying Consolidated Statements of Income: Years ended December 31, (In thousands) 2018 2017 2016 Restricted stock $ 11,612 $ 12,276 $ 11,395 Stock options — — 43 Stock compensation expense $ 11,612 $ 12,276 $ 11,438 Income tax benefit $ 8,545 $ 11,849 $ 4,132
Summary of Restricted Stock and Stock Option Activity	The following table provides a summary of the activity under the stock compensation plans for the year ended December 31, 2018 : Unvested Restricted Stock Awards Outstanding Stock Options Outstanding Time-Based Performance-Based Number of Shares Weighted-Average Grant Date Fair Value Number of Shares Weighted-Average Grant Date Fair Value Number of Shares Weighted-Average Exercise Price Balance at January 1, 2018 207,800 $ 43.16 78,916 $ 45.35 673,039 $ 18.75 Granted 151,833 58.34 75,707 55.82 — — Vested restricted stock awards (1) 171,269 45.54 71,357 46.50 — — Forfeited 10,923 52.94 13,847 51.19 — — Exercised options — — — — 192,247 11.30 Balance at December 31, 2018 177,441 53.05 69,419 54.43 480,792 21.73 (1)
Summary of Options Outstanding and Options Exercisable	The following table summarizes information for options, all of which are both outstanding and exercisable, at December 31, 2018 : Range of Exercise Prices Number of Shares Weighted-Average Remaining Contractual Life (years) Weighted-Average Exercise Price $ 5.14 - 12.85 48,568 0.5 $ 7.42 $ 23.00 - 23.81 432,224 3.7 23.34 480,792 3.4 $ 21.73

Segment Reporting (Tables)

Segment Reporting (Tables)	12 Months Ended
	Dec. 31, 2018
Segment Reporting [Abstract]
Operating Results And Total Assets Reportable Segments	The following table presents total assets for Webster's reportable segments and the Corporate and Reconciling category: Total Assets (In thousands) Commercial HSA Community Banking Corporate and Consolidated At December 31, 2018 $ 10,477,050 $ 70,826 $ 8,727,335 $ 8,335,104 $ 27,610,315 At December 31, 2017 9,350,028 76,308 8,909,671 8,151,638 26,487,645 The following tables present the operating results, including all appropriate allocations, for Webster’s reportable segments and the Corporate and Reconciling category: Year ended December 31, 2018 (In thousands) Commercial HSA Community Banking Corporate and Consolidated Net interest income $ 356,509 $ 143,255 $ 404,869 $ 2,048 $ 906,681 Provision for loan and lease losses 34,773 — 7,227 — 42,000 Net interest income after provision for loan and lease losses 321,736 143,255 397,642 2,048 864,681 Non-interest income 64,765 89,323 109,669 18,811 282,568 Non-interest expense 174,054 124,594 384,599 22,369 705,616 Income (loss) before income tax expense 212,447 107,984 122,712 (1,510 ) 441,633 Income tax expense (benefit) 52,262 28,076 24,420 (23,543 ) 81,215 Net income $ 160,185 $ 79,908 $ 98,292 $ 22,033 $ 360,418 Year ended December 31, 2017 (In thousands) Commercial HSA Community Banking Corporate and Consolidated Net interest income (loss) $ 322,393 $ 104,704 $ 383,700 $ (14,510 ) $ 796,287 Provision for loan and lease losses 38,518 — 2,382 — 40,900 Net interest income (loss) after provision for loan and lease losses 283,875 104,704 381,318 (14,510 ) 755,387 Non-interest income 55,194 77,378 107,368 19,538 259,478 Non-interest expense 154,037 113,143 373,081 20,814 661,075 Income (loss) before income tax expense 185,032 68,939 115,605 (15,786 ) 353,790 Income tax expense (benefit) 51,438 19,165 32,137 (4,389 ) 98,351 Net income (loss) $ 133,594 $ 49,774 $ 83,468 $ (11,397 ) $ 255,439 Year ended December 31, 2016 (In thousands) Commercial HSA Community Banking Corporate and Consolidated Net interest income (loss) $ 287,596 $ 81,451 $ 367,137 $ (17,671 ) $ 718,513 Provision for loan and lease losses 37,455 — 18,895 — 56,350 Net interest income (loss) after provision for loan and lease losses 250,141 81,451 348,242 (17,671 ) 662,163 Non-interest income 57,253 71,710 110,197 25,318 264,478 Non-interest expense 138,379 97,152 369,132 18,528 623,191 Income (loss) before income tax expense 169,015 56,009 89,307 (10,881 ) 303,450 Income tax expense (benefit) 53,649 17,779 28,348 (3,453 ) 96,323 Net income (loss) $ 115,366 $ 38,230 $ 60,959 $ (7,428 ) $ 207,127

Revenue from contracts with C_2

Revenue from contracts with Customers Disaggregation of Revenue (Tables)	12 Months Ended
	Dec. 31, 2018
Revenue from Contract with Customer [Abstract]
Disaggregation of Revenue [Table Text Block]	The following tables present the disaggregation by operating segment and major revenue stream, with disaggregated revenue reconciled to segment revenue as presented in Note 19: Segment Reporting : Year ended December 31, 2018 (In thousands) Commercial HSA Community Corporate and Consolidated Major Revenue Streams Deposit service fees $ 12,775 $ 85,809 $ 63,522 $ 77 $ 162,183 Wealth and investment services 10,145 — 22,732 (34 ) 32,843 Other income — 3,514 2,133 — 5,647 Revenue from contracts with customers 22,920 89,323 88,387 43 200,673 Non-interest income within the scope of other GAAP topics 41,845 — 21,282 18,768 81,895 Total non-interest income $ 64,765 $ 89,323 $ 109,669 $ 18,811 $ 282,568 Year ended December 31, 2017 (In thousands) Commercial HSA Community Corporate and Consolidated Major Revenue Streams Deposit service fees $ 12,203 $ 74,448 $ 64,194 $ 292 $ 151,137 Wealth and investment services 9,817 — 21,274 (36 ) 31,055 Other income — 2,930 823 — 3,753 Revenue from contracts with customers 22,020 77,378 86,291 256 185,945 Non-interest income within the scope of other GAAP topics 33,174 — 21,077 19,282 73,533 Total non-interest income $ 55,194 $ 77,378 $ 107,368 $ 19,538 $ 259,478 Year ended December 31, 2016 (In thousands) Commercial HSA Community Corporate and Consolidated Major Revenue Streams Deposit service fees $ 11,143 $ 66,162 $ 63,143 $ 237 $ 140,685 Wealth and investment services 9,150 — 19,842 (30 ) 28,962 Other income — 2,858 872 — 3,730 Revenue from contracts with customers 20,293 69,020 83,857 207 173,377 Non-interest income within the scope of other GAAP topics 36,960 2,690 26,340 25,111 91,101 Total non-interest income $ 57,253 $ 71,710 $ 110,197 $ 25,318 $ 264,478

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2018
Commitments and Contingencies Disclosure [Abstract]
Schedule of Future Minimum Rental Payments and Receipts for Leases	The following table summarizes future minimum rental payments and receipts under lease agreements: At December 31, 2018 (In thousands) Rental Payments Rental Receipts 2019 $ 30,889 $ 805 2020 30,049 667 2021 28,274 547 2022 24,498 493 2023 21,231 427 Thereafter 78,882 1,403 Total future minimum rental payments and receipts $ 213,823 $ 4,342
Outstanding Financial Instruments Contract Amounts Represent Credit Risk	The following table summarizes the outstanding amounts of credit-related financial instruments with off-balance sheet risk: At December 31, (In thousands) 2018 2017 Commitments to extend credit $ 5,840,585 $ 5,567,687 Standby letter of credit 189,040 195,902 Commercial letter of credit 21,181 43,200 Total credit-related financial instruments with off-balance sheet risk $ 6,050,806 $ 5,806,789
Reserve For Unfunded Credit Commitments	The following table provides a summary of activity in the reserve for loan repurchases: Years ended December 31, (In thousands) 2018 2017 2016 Beginning balance $ 872 $ 790 $ 1,192 (Benefit) provision charged to expense (160 ) 100 (303 ) Repurchased loans and settlements charged off (38 ) (18 ) (99 ) Ending balance $ 674 $ 872 $ 790 Years ended December 31, (In thousands) 2018 2017 2016 Beginning balance $ 2,362 $ 2,287 $ 2,119 Provision 144 75 168 Ending balance $ 2,506 $ 2,362 $ 2,287

Parent Company Information (Tab

Parent Company Information (Tables)	12 Months Ended
	Dec. 31, 2018
Condensed Financial Information Disclosure [Abstract]
Schedule of Parent Company Information Balance Sheet	Condensed Balance Sheets December 31, (In thousands) 2018 2017 Assets: Cash and due from banks $ 317,473 $ 181,085 Intercompany debt securities 150,000 150,000 Investment in subsidiaries 2,633,848 2,585,955 Due from subsidiaries 36 — Alternative investments 3,252 2,939 Other assets 12,003 13,252 Total assets $ 3,116,612 $ 2,933,231 Liabilities and shareholders’ equity: Senior notes $ 148,701 $ 148,447 Junior subordinated debt 77,320 77,320 Accrued interest payable 2,664 2,616 Due to subsidiaries — 575 Other liabilities 1,412 2,315 Total liabilities 230,097 231,273 Shareholders’ equity 2,886,515 2,701,958 Total liabilities and shareholders’ equity $ 3,116,612 $ 2,933,231
Schedule of Parent Company Information Income Statement	Condensed Statements of Income Years ended December 31, (In thousands) 2018 2017 2016 Operating Income: Dividend income from bank subsidiary $ 290,000 $ 120,000 $ 145,000 Interest on securities and deposits 7,342 4,477 1,911 Loss on sale of investment securities — — (2,410 ) Alternative investments income 290 1,504 176 Other non-interest income 805 204 7,485 Total operating income 298,437 126,185 152,162 Operating Expense: Interest expense on borrowings 11,127 10,380 9,981 Non-interest expense 19,105 23,008 17,739 Total operating expense 30,232 33,388 27,720 Income before income tax benefit and equity in undistributed earnings of subsidiaries 268,205 92,797 124,442 Income tax benefit 2,207 3,004 3,086 Equity in undistributed earnings of subsidiaries 90,006 159,638 79,599 Net income $ 360,418 $ 255,439 $ 207,127
Schedule of Parent Company Information Comprehensive Income Statement	Condensed Statements of Comprehensive Income Years ended December 31, (In thousands) 2018 2017 2016 Net income $ 360,418 $ 255,439 $ 207,127 Other comprehensive income (loss), net of tax: Net unrealized gains on available for sale securities — — 584 Net unrealized gains on derivative instruments 1,447 1,216 1,223 Other comprehensive loss of subsidiaries and associated companies (40,568 ) (106 ) (694 ) Other comprehensive income (loss), net of tax (39,121 ) 1,110 1,113 Comprehensive income $ 321,297 $ 256,549 $ 208,240
Schedule of Parent Company Information Cash Flow Statement	Condensed Statements of Cash Flows Years ended December 31, (In thousands) 2018 2017 2016 Net cash provided by operating activities $ 282,986 $ 115,957 $ 127,899 Investing activities: Proceeds from sale of available for sale securities — — 1,089 Purchases of intercompany debt securities — — (150,000 ) Proceeds from the sale of other assets — 7,581 — Net cash provided by (used for) investing activities — 7,581 (148,911 ) Financing activities: Preferred stock issued — 145,056 — Preferred stock redeemed — (122,710 ) — Cash dividends paid to common shareholders (114,959 ) (94,630 ) (89,522 ) Cash dividends paid to preferred shareholders (7,875 ) (8,096 ) (8,096 ) Exercise of stock options 2,173 8,259 11,762 Excess tax benefits from stock-based compensation — — 3,204 Common stock repurchased and acquired from stock compensation plan activity (25,937 ) (23,279 ) (22,870 ) Common stock warrants repurchased — — (163 ) Net cash used for financing activities (146,598 ) (95,400 ) (105,685 ) Increase (decrease) in cash and due from banks 136,388 28,138 (126,697 ) Cash and due from banks at beginning of year 181,085 152,947 279,644 Cash and due from banks at end of year $ 317,473 $ 181,085 $ 152,947

Selected Quarterly Consolidat_2

Selected Quarterly Consolidated Financial Information (Unaudited) (Tables)	12 Months Ended
	Dec. 31, 2018
Selected Quarterly Financial Information [Abstract]
Schedule of Quarterly Financial Information	2018 (In thousands, except per share data) First Quarter Second Quarter Third Quarter Fourth Quarter Interest income $ 245,921 $ 260,491 $ 268,363 $ 280,392 Interest expense 31,753 35,481 37,991 43,261 Net interest income 214,168 225,010 230,372 237,131 Provision for loan and lease losses 11,000 10,500 10,500 10,000 Non-interest income 68,747 68,374 72,284 73,163 Non-interest expense 171,615 180,459 178,783 174,759 Income before income tax expense 100,300 102,425 113,373 125,535 Income tax expense 20,075 20,743 13,700 26,697 Net income $ 80,225 $ 81,682 $ 99,673 $ 98,838 Earnings applicable to common shareholders $ 78,083 $ 79,489 $ 97,460 $ 96,666 Earnings per common share: Basic $ 0.85 $ 0.87 $ 1.06 $ 1.05 Diluted 0.85 0.86 1.06 1.05 2017 (In thousands, except per share data) First Quarter Second Quarter Third Quarter Fourth Quarter Interest income $ 219,680 $ 226,789 $ 231,021 $ 236,115 Interest expense 27,016 29,002 30,117 31,183 Net interest income 192,664 197,787 200,904 204,932 Provision for loan and lease losses 10,500 7,250 10,150 13,000 Non-interest income 63,042 64,551 65,846 66,039 Non-interest expense 163,784 164,419 161,823 171,049 Income before income tax expense 81,422 90,669 94,777 86,922 Income tax expense 21,951 29,090 30,281 17,029 Net income $ 59,471 $ 61,579 $ 64,496 $ 69,893 Earnings applicable to common shareholders $ 57,342 $ 59,485 $ 62,426 $ 67,710 Earnings per common share: Basic $ 0.62 $ 0.65 $ 0.68 $ 0.74 Diluted 0.62 0.64 0.67 0.73

Summary of Significant Accoun_4

Summary of Significant Accounting Policies Summary of Significant Accounting Policies (Narrative) (Loans) (Detail)	12 Months Ended
	Dec. 31, 2018
Financing Receivable, Recorded Investment, Past Due [Line Items]
Threshold Period Past Due for Nonperforming Status of Financing Receivables	90 days
Threshold period past due for write-off of financing receivable (in days)	180 days
Residential Portfolio Segment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Threshold Period Past Due for Nonperforming Status of Financing Receivables	90 days
Commercial Portfolio Segment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Threshold Period Past Due for Nonperforming Status of Financing Receivables	90 days
Other Real Estate Owned [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Threshold period past due for write-off of financing receivable (in days)	90 days

Significant Accounting Policies

Significant Accounting Policies (Premises and Equipment) (Detail)	12 Months Ended
	Dec. 31, 2018
Building and Building Improvements [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Useful life (in years)	5 years
Building and Building Improvements [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Useful life (in years)	40 years
Leasehold Improvements [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Useful life (in years)	5 years
Leasehold Improvements [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Useful life (in years)	20 years
Furniture and Fixtures [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Useful life (in years)	5 years
Furniture and Fixtures [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Useful life (in years)	10 years
Data Processing and Software [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Useful life (in years)	3 years
Data Processing and Software [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Useful life (in years)	7 years

Summary of Significant Accoun_5

Summary of Significant Accounting Policies (Share Based Compensation) (Narrative) (Detail)	12 Months Ended
	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period (in years)	1 year
Performance Based Restricted Stock Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period (in years)	3 years
Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period (in years)	3 years
Award vesting percentage	50.00%
Share-based Compensation Award, Tranche One [Member] | Performance Shares [Member] | Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting percentage	0.00%
Share-based Compensation Award, Tranche One [Member] | Performance Shares [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting percentage	150.00%

Summary of Significant Accoun_6

Summary of Significant Accounting Policies Change in Accounting Estimate (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Change in Accounting Estimate [Line Items]
Deposit insurance	$ 34,749	$ 25,649	$ 26,006
Regulatory Reviews of Filings [Member] | Corporate, Non-Segment [Member]
Change in Accounting Estimate [Line Items]
Deposit insurance	$ 10,000

Summary of Significant Accoun_7

Summary of Significant Accounting Policies New Accounting Pronouncement or Change in Accounting Principle (Details) $ in Millions	Dec. 31, 2018USD ($)
Accounting Standards Update 2016-01 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Cumulative Effect of Change on Equity or Net Assets	$ 1.4
Accounting Standards Update 2017-08 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Cumulative Effect of Change on Equity or Net Assets	$ (2.8)

Summary of Significant Accoun_8

Summary of Significant Accounting Policies New Accounting Pronouncements - Narrative (Details) - Scenario, Forecast [Member] - Accounting Standards Update 2016-02 [Member] $ in Millions	Jan. 01, 2019USD ($)
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating Lease, Right-of-Use Asset	$ 160
Operating Lease, Liability	$ 180

Investment Securities (Summary

Investment Securities (Summary Of Investment Securities) (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Debt Securities, Available-for-sale [Abstract]
Debt Securities, Available-for-sale, Amortized Cost	$ 2,994,616	$ 2,675,131
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	2,783	7,173
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	98,669	44,267
Debt Securities, Available-for-sale	2,898,730	2,638,037
Debt Securities, Held-to-maturity, Fair Value to Amortized Cost [Abstract]
Amortized Cost	4,325,420	4,487,392
Unrealized Gains	11,902	28,413
Unrealized Losses	(128,201)	(59,455)
Fair Value	4,209,121	4,456,350
US Treasury Bill Securities [Member]
Debt Securities, Available-for-sale [Abstract]
Debt Securities, Available-for-sale, Amortized Cost	7,549	1,247
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	1	0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	0	0
Debt Securities, Available-for-sale	7,550	1,247
Collateralized Mortgage Obligations [Member]
Debt Securities, Available-for-sale [Abstract]
Debt Securities, Available-for-sale, Amortized Cost	238,968	308,989
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	412	1,158
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	4,457	3,814
Debt Securities, Available-for-sale	234,923	306,333
Debt Securities, Held-to-maturity, Fair Value to Amortized Cost [Abstract]
Amortized Cost	208,113	260,114
Unrealized Gains	287	664
Unrealized Losses	(5,255)	(4,824)
Fair Value	203,145	255,954
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Debt Securities, Available-for-sale [Abstract]
Debt Securities, Available-for-sale, Amortized Cost	1,521,534	1,124,960
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	1,631	2,151
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	42,076	19,270
Debt Securities, Available-for-sale	1,481,089	1,107,841
Debt Securities, Held-to-maturity, Fair Value to Amortized Cost [Abstract]
Amortized Cost	2,517,823	2,569,735
Unrealized Gains	8,250	16,989
Unrealized Losses	(79,701)	(37,442)
Fair Value	2,446,372	2,549,282
Agency commercial mortgage-backed securities (agency CMBS) [Member]
Debt Securities, Available-for-sale [Abstract]
Debt Securities, Available-for-sale, Amortized Cost	608,167	608,276
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	0	0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	41,930	20,250
Debt Securities, Available-for-sale	566,237	588,026
Debt Securities, Held-to-maturity, Fair Value to Amortized Cost [Abstract]
Amortized Cost	667,500	696,566
Unrealized Gains	53	0
Unrealized Losses	(22,572)	(10,011)
Fair Value	644,981	686,555
Commercial Mortgage Backed Securities [Member]
Debt Securities, Available-for-sale [Abstract]
Debt Securities, Available-for-sale, Amortized Cost	447,897	358,984
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	645	2,157
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	2,961	74
Debt Securities, Available-for-sale	445,581	361,067
Debt Securities, Held-to-maturity, Fair Value to Amortized Cost [Abstract]
Amortized Cost	216,943	249,273
Unrealized Gains	405	2,175
Unrealized Losses	(2,388)	(620)
Fair Value	214,960	250,828
Collateralized loan obligations (CLO) [Member]
Debt Securities, Available-for-sale [Abstract]
Debt Securities, Available-for-sale, Amortized Cost	114,641	209,075
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	94	910
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	1,964	134
Debt Securities, Available-for-sale	112,771	209,851
Trust Preferred Securities Single Issuers [Member]
Debt Securities, Available-for-sale [Abstract]
Debt Securities, Available-for-sale, Amortized Cost	0	7,096
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	0	0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	0	46
Debt Securities, Available-for-sale	0	7,050
Corporate Debt Securities [Member]
Debt Securities, Available-for-sale [Abstract]
Debt Securities, Available-for-sale, Amortized Cost	55,860	56,504
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	0	797
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	5,281	679
Debt Securities, Available-for-sale	50,579	56,622
Municipal Bonds [Member]
Debt Securities, Held-to-maturity, Fair Value to Amortized Cost [Abstract]
Amortized Cost	715,041	711,381
Unrealized Gains	2,907	8,584
Unrealized Losses	(18,285)	(6,558)
Fair Value	699,663	713,407
Mortgage-backed Securities, Issued by Private Enterprises [Member]
Debt Securities, Held-to-maturity, Fair Value to Amortized Cost [Abstract]
Amortized Cost	0	323
Unrealized Gains	0	1
Unrealized Losses	0	0
Fair Value	$ 0	$ 324

Investment Securities (Other Th

Investment Securities (Other Than Temporary Impairment Credit Losses Recognized In Earnings) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Roll Forward]
Balance of OTTI, beginning of period	$ 1,364	$ 3,243	$ 3,288
Reduction for securities sold, called	(542)	(2,005)	(194)
Additions for OTTI not previously recognized in earnings	0	126	149
Balance of OTTI, end of period	$ 822	$ 1,364	$ 3,243

Investment Securities (Summar_2

Investment Securities (Summary Of Gross Unrealized Losses Not Considered OTTI) (Detail) $ in Thousands	Dec. 31, 2018USD ($)holding	Dec. 31, 2017USD ($)holding
Schedule of Investments [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	$ 799,954	$ 650,514
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(8,602)	(4,869)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	1,756,617	1,265,234
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	$ (90,067)	$ (39,398)
Debt Securities, Available-for-sale, Unrealized Loss Position, Number of Positions | holding	309	212
Debt Securities, Available-for-sale, Unrealized Loss Position	$ 2,556,571	$ 1,915,748
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(98,669)	(44,267)
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	382,558	1,536,069
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	3,069	13,687
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	3,257,871	1,655,375
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	$ 125,132	$ 45,768
Held-to-maturity, Number of Holdings - Total | holding	596	388
Held-to-maturity, Fair Value - Total	$ 3,640,429	$ 3,191,444
Held-to-maturity, Unrealized Losses - Total	(128,201)	(59,455)
Collateralized Mortgage Obligations [Member]
Schedule of Investments [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	15,524	81,001
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(72)	(449)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	180,641	119,104
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	$ (4,385)	$ (3,365)
Debt Securities, Available-for-sale, Unrealized Loss Position, Number of Positions | holding	36	27
Debt Securities, Available-for-sale, Unrealized Loss Position	$ 196,165	$ 200,105
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(4,457)	(3,814)
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	691	98,090
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	1	1,082
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	182,396	106,775
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	$ 5,254	$ 3,742
Held-to-maturity, Number of Holdings - Total | holding	25	22
Held-to-maturity, Fair Value - Total	$ 183,087	$ 204,865
Held-to-maturity, Unrealized Losses - Total	(5,255)	(4,824)
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Schedule of Investments [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	321,678	416,995
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(2,078)	(2,920)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	975,084	606,021
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	$ (39,998)	$ (16,350)
Debt Securities, Available-for-sale, Unrealized Loss Position, Number of Positions | holding	184	135
Debt Securities, Available-for-sale, Unrealized Loss Position	$ 1,296,762	$ 1,023,016
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(42,076)	(19,270)
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	288,635	762,107
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	1,916	4,555
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	1,892,951	1,197,839
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	$ 77,785	$ 32,887
Held-to-maturity, Number of Holdings - Total | holding	272	205
Held-to-maturity, Fair Value - Total	$ 2,181,586	$ 1,959,946
Held-to-maturity, Unrealized Losses - Total	(79,701)	(37,442)
Agency commercial mortgage-backed securities (agency CMBS) [Member]
Schedule of Investments [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months		54,182
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		(851)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	566,237	533,844
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	$ (41,930)	$ (19,399)
Debt Securities, Available-for-sale, Unrealized Loss Position, Number of Positions | holding	37	36
Debt Securities, Available-for-sale, Unrealized Loss Position	$ 566,237	$ 588,026
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(41,930)	(20,250)
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value		576,770
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		7,599
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	635,284	109,785
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	$ 22,572	$ 2,412
Held-to-maturity, Number of Holdings - Total | holding	56	56
Held-to-maturity, Fair Value - Total	$ 635,284	$ 686,555
Held-to-maturity, Unrealized Losses - Total	(22,572)	(10,011)
Commercial Mortgage Backed Securities [Member]
Schedule of Investments [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	343,457	23,869
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(2,937)	$ (74)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	5,193
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	$ (24)
Debt Securities, Available-for-sale, Unrealized Loss Position, Number of Positions | holding	39	6
Debt Securities, Available-for-sale, Unrealized Loss Position	$ 348,650	$ 23,869
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(2,961)	(74)
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	24,881	92,670
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	270	413
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	132,464	14,115
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	$ 2,118	$ 207
Held-to-maturity, Number of Holdings - Total | holding	20	13
Held-to-maturity, Fair Value - Total	$ 157,345	$ 106,785
Held-to-maturity, Unrealized Losses - Total	(2,388)	(620)
Collateralized loan obligations (CLO) [Member]
Schedule of Investments [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	83,305	56,335
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(1,695)	$ (134)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	14,873
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	$ (269)
Debt Securities, Available-for-sale, Unrealized Loss Position, Number of Positions | holding	5	3
Debt Securities, Available-for-sale, Unrealized Loss Position	$ 98,178	$ 56,335
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(1,964)	(134)
Trust Preferred Securities Single Issuers [Member]
Schedule of Investments [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months		7,050
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		$ (46)
Debt Securities, Available-for-sale, Unrealized Loss Position, Number of Positions | holding		1
Debt Securities, Available-for-sale, Unrealized Loss Position		$ 7,050
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss		(46)
Municipal Bonds [Member]
Schedule of Investments [Line Items]
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	68,351	6,432
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	882	38
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	414,776	226,861
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	$ 17,403	$ 6,520
Held-to-maturity, Number of Holdings - Total | holding	223	92
Held-to-maturity, Fair Value - Total	$ 483,127	$ 233,293
Held-to-maturity, Unrealized Losses - Total	(18,285)	(6,558)
Corporate Debt Securities [Member]
Schedule of Investments [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	35,990	11,082
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(1,820)	(395)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	14,589	6,265
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	$ (3,461)	$ (284)
Debt Securities, Available-for-sale, Unrealized Loss Position, Number of Positions | holding	8	4
Debt Securities, Available-for-sale, Unrealized Loss Position	$ 50,579	$ 17,347
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	$ (5,281)	$ (679)

Investment Securities (Narrativ

Investment Securities (Narrative) (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Schedule of Investments [Line Items]
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	$ 98,669	$ 44,267
Held-to-maturity securities, accumulated unrealized holding loss	(128,201)	(59,455)
Securities pledged to secure public funds, carrying value	2,200,000	2,400,000
Collateralized Mortgage Obligations [Member]
Schedule of Investments [Line Items]
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	4,457	3,814
Held-to-maturity securities, accumulated unrealized holding loss	(5,255)	(4,824)
Agency mortgage-backed securities (agency MBS) [Member]
Schedule of Investments [Line Items]
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	42,076	19,270
Held-to-maturity securities, accumulated unrealized holding loss	(79,701)	(37,442)
Agency commercial mortgage-backed securities (agency CMBS) [Member]
Schedule of Investments [Line Items]
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	41,930	20,250
Held-to-maturity securities, accumulated unrealized holding loss	(22,572)	(10,011)
Non-agency commercial mortgage-backed securities (non-agency CMBS) [Member]
Schedule of Investments [Line Items]
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	2,961	74
Held-to-maturity securities, accumulated unrealized holding loss	(2,388)	(620)
Collateralized loan obligations (CLO) [Member]
Schedule of Investments [Line Items]
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	1,964	134
Corporate Debt Securities [Member]
Schedule of Investments [Line Items]
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	5,281	679
Municipal bonds and notes [Member]
Schedule of Investments [Line Items]
Held-to-maturity securities, accumulated unrealized holding loss	(18,285)	$ (6,558)
Callable at the option of the counterparty [Member]
Schedule of Investments [Line Items]
Securities available-for-sale, at fair value	$ 1,200,000

Investment Securities (Summar_3

Investment Securities (Summary Of Sale Proceeds Of Available For Sale Securities) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Investments, Debt and Equity Securities [Abstract]
Proceeds from Sale of Debt Securities, Available-for-sale	$ 0	$ 0	$ 259,283
Gains			2,900
Losses			2,500
Debt Securities, Available-for-sale, Realized Gain (Loss)	$ 0	$ 0	$ (414)

Investment Securities (Summar_4

Investment Securities (Summary Of Debt Securities By Contractual Maturity) (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Debt Securities, Available-for-sale, Amortized Cost, Fiscal Year Maturity [Abstract]
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, within One Year, Amortized Cost	$ 27,880
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, after One Through Five Years, Amortized Cost	17,126
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, after Five Through Ten Years, Amortized Cost	275,969
Debt Securities, Available-for-sale, Allocated and Single Maturity Date, Maturity, after 10 Years, Amortized Cost	2,673,641
Debt Securities, Available-for-sale, Amortized Cost	2,994,616	$ 2,675,131
Debt Securities, Available-for-sale, Fair Value, Fiscal Year Maturity [Abstract]
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, within One Year, Fair Value	27,865
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, after One Through Five Years, Fair Value	17,155
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, after Five Through Ten Years, Fair Value	274,027
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, after 10 Years, Fair Value	2,579,683
Available for Sale, Fair Value - Total debt securities	2,898,730	2,638,037
Debt Securities, Held-to-maturity, Maturity, Allocated and Single Maturity Date, Amortized Cost [Abstract]
Debt Securities, Held-to-maturity, Maturity, Allocated and Single Maturity Date, within One Year, Amortized Cost	7,047
Debt Securities, Held-to-maturity, Maturity, Allocated and Single Maturity Date, after One Through Five Years, Amortized Cost	7,909
Debt Securities, Held-to-maturity, Maturity, Allocated and Single Maturity Date, after Five Through Ten Years, Amortized Cost	31,455
Debt Securities, Held-to-maturity, Maturity, Allocated and Single Maturity Date, after 10 Years, Amortized Cost	4,279,009
Amortized Cost	4,325,420	4,487,392
Debt Securities, Held-to-maturity, Maturity, Fair Value [Abstract]
Debt Securities, Held-to-maturity, Maturity, Allocated and Single Maturity Date, within One Year, Fair Value	7,059
Debt Securities, Held-to-maturity, Maturity, Allocated and Single Maturity Date, after One Through Five Years, Fair Value	8,019
Debt Securities, Held-to-maturity, Maturity, Allocated and Single Maturity Date, after Five Through Ten Years, Fair Value	31,500
Debt Securities, Held-to-maturity, Maturity, Allocated and Single Maturity Date, after 10 Years, Fair Value	4,162,543
Debt Securities, Held-to-maturity, Fair Value	$ 4,209,121	$ 4,456,350

Variable Interest Entities (Det

Variable Interest Entities (Details) - Variable Interest Entity, Not Primary Beneficiary [Member] - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Other Assets [Member]
Variable Interest Entity [Line Items]
Variable interest entities, investments, carrying value	$ 29.1	$ 33.5
Accounts Payable and Accrued Liabilities [Member]
Variable Interest Entity [Line Items]
Variable interest entities, unfunded commitments	10.4	17.3
Other Investments [Member]
Variable Interest Entity [Line Items]
Variable interest entities, investments, carrying value	17.6	13.8
Unfunded Loan Commitment [Member]
Variable Interest Entity [Line Items]
Variable interest entities, total exposure of other investments including unfunded commitments	$ 31	$ 22.9

Loans and Leases (Detail)

Loans and Leases (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans and Leases	$ 18,465,489	$ 17,523,858	$ 17,026,588
Unamortized premiums	13,900	20,600
Pledged loans as collateral	7,100,000
Residential Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans and Leases	4,416,637	4,490,878	4,254,682
Consumer Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans and Leases	2,396,704	2,590,225	2,684,500
Commercial Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans and Leases	6,216,606	5,368,694	4,940,931
Commercial Real Estate Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans and Leases	4,927,145	4,523,828	4,510,846
Finance Leases Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans and Leases	$ 508,397	$ 550,233	$ 635,629

Loans and Leases (Summary Of Lo

Loans and Leases (Summary Of Loan And Lease Portfolio Aging By Class Of Loan) (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due and Non-accrual	$ 189,199	$ 172,360
90 or More Days Past Due and Accruing	104	892
Non-accrual	154,767	126,513
Current	18,276,290	17,351,498
Total Loans and Leases	18,465,489	17,523,858	$ 17,026,588
Residential Portfolio Segment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due and Non-accrual	62,002	58,270
90 or More Days Past Due and Accruing	0	0
Non-accrual	49,188	44,481
Current	4,354,635	4,432,608
Total Loans and Leases	4,416,637	4,490,878	4,254,682
Consumer Portfolio Segment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans and Leases	2,396,704	2,590,225	2,684,500
Consumer Portfolio Segment [Member] | Home Equity Loan [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due and Non-accrual	48,130	54,083
90 or More Days Past Due and Accruing	0	0
Non-accrual	33,495	35,645
Current	2,121,049	2,298,185
Total Loans and Leases	2,169,179	2,352,268
Consumer Portfolio Segment [Member] | Consumer Borrower [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due and Non-accrual	4,225	5,707
90 or More Days Past Due and Accruing	0	0
Non-accrual	1,494	1,707
Current	223,300	232,250
Total Loans and Leases	227,525	237,957
Commercial Portfolio Segment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans and Leases	6,216,606	5,368,694	4,940,931
Commercial Portfolio Segment [Member] | Commercial and Industrial Sector [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due and Non-accrual	57,627	45,673
90 or More Days Past Due and Accruing	104	644
Non-accrual	55,810	39,214
Current	5,189,808	4,488,242
Total Loans and Leases	5,247,435	4,533,915
Commercial Portfolio Segment [Member] | Asset Based Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due and Non-accrual	224	589
90 or More Days Past Due and Accruing	0	0
Non-accrual	224	589
Current	968,947	834,190
Total Loans and Leases	969,171	834,779
Commercial Real Estate Portfolio Segment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans and Leases	4,927,145	4,523,828	4,510,846
Commercial Real Estate Portfolio Segment [Member] | Construction Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due and Non-accrual	0	0
90 or More Days Past Due and Accruing	0	0
Non-accrual	0	0
Current	218,831	279,554
Total Loans and Leases	218,831	279,554
Commercial Real Estate Portfolio Segment [Member] | Real Estate Loan [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due and Non-accrual	9,762	5,287
90 or More Days Past Due and Accruing	0	248
Non-accrual	8,242	4,484
Current	4,698,552	4,238,987
Total Loans and Leases	4,708,314	4,244,274
Finance Leases Portfolio Segment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due and Non-accrual	7,229	2,751
90 or More Days Past Due and Accruing	0	0
Non-accrual	6,314	393
Current	501,168	547,482
Total Loans and Leases	508,397	550,233	$ 635,629
Financing Receivables, 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due and Non-accrual	22,333	31,289
Financing Receivables, 30 to 59 Days Past Due [Member] | Residential Portfolio Segment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due and Non-accrual	8,513	8,643
Financing Receivables, 30 to 59 Days Past Due [Member] | Consumer Portfolio Segment [Member] | Home Equity Loan [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due and Non-accrual	9,250	12,668
Financing Receivables, 30 to 59 Days Past Due [Member] | Consumer Portfolio Segment [Member] | Consumer Borrower [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due and Non-accrual	1,774	2,556
Financing Receivables, 30 to 59 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Commercial and Industrial Sector [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due and Non-accrual	1,011	5,212
Financing Receivables, 30 to 59 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Asset Based Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due and Non-accrual	0	0
Financing Receivables, 30 to 59 Days Past Due [Member] | Commercial Real Estate Portfolio Segment [Member] | Construction Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due and Non-accrual	0	0
Financing Receivables, 30 to 59 Days Past Due [Member] | Commercial Real Estate Portfolio Segment [Member] | Real Estate Loan [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due and Non-accrual	1,275	478
Financing Receivables, 30 to 59 Days Past Due [Member] | Finance Leases Portfolio Segment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due and Non-accrual	510	1,732
Financing Receivables, 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due and Non-accrual	11,995	13,666
Financing Receivables, 60 to 89 Days Past Due [Member] | Residential Portfolio Segment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due and Non-accrual	4,301	5,146
Financing Receivables, 60 to 89 Days Past Due [Member] | Consumer Portfolio Segment [Member] | Home Equity Loan [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due and Non-accrual	5,385	5,770
Financing Receivables, 60 to 89 Days Past Due [Member] | Consumer Portfolio Segment [Member] | Consumer Borrower [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due and Non-accrual	957	1,444
Financing Receivables, 60 to 89 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Commercial and Industrial Sector [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due and Non-accrual	702	603
Financing Receivables, 60 to 89 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Asset Based Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due and Non-accrual	0	0
Financing Receivables, 60 to 89 Days Past Due [Member] | Commercial Real Estate Portfolio Segment [Member] | Construction Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due and Non-accrual	0	0
Financing Receivables, 60 to 89 Days Past Due [Member] | Commercial Real Estate Portfolio Segment [Member] | Real Estate Loan [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due and Non-accrual	245	77
Financing Receivables, 60 to 89 Days Past Due [Member] | Finance Leases Portfolio Segment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due and Non-accrual	$ 405	$ 626

Loans and Leases (Narrative) (D

Loans and Leases (Narrative) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Loans and Leases Receivable Disclosure [Abstract]
Interest on non-accrual loans that would have been recorded as additional interest income	$ 9.7	$ 8.4	$ 11
Write-down of TDR's	$ (14.3)	$ (3.2)	$ (18.6)

Loans and Leases (Allowance For

Loans and Leases (Allowance For Loan And Lease Losses By Portfolio Segment) (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2016
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance, beginning of period				$ 199,994				$ 194,320	$ 199,994	$ 194,320	$ 174,990
Provision (benefit) charged to expense	$ 10,000	$ 10,500	$ 10,500	11,000	$ 13,000	$ 10,150	$ 7,250	10,500	42,000	40,900	56,350
Losses charged off									(43,387)	(44,927)	(46,912)
Recoveries									13,746	9,701	9,892
Balance, end of period	212,353			199,994	199,994			194,320	199,994	194,320	174,990	$ 194,320
Individually evaluated for impairment	15,350				16,554							18,593
Collectively evaluated for impairment	197,003				183,440							175,727
Individually evaluated for impairment	259,330				246,753							249,355
Collectively evaluated for impairment	18,206,159				17,277,105							16,777,233
Total Loans and Leases	18,465,489				17,523,858							17,026,588
Residential Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance, beginning of period				19,058				23,226	19,058	23,226	25,876
Provision (benefit) charged to expense									2,016	(2,692)	230
Losses charged off									(3,455)	(2,500)	(4,636)
Recoveries									1,980	1,024	1,756
Balance, end of period	19,599			19,058	19,058			23,226	19,058	23,226	25,876	23,226
Individually evaluated for impairment	4,286				4,805							8,090
Collectively evaluated for impairment	15,313				14,253							15,136
Individually evaluated for impairment	103,531				114,295							119,424
Collectively evaluated for impairment	4,313,106				4,376,583							4,135,258
Total Loans and Leases	4,416,637				4,490,878							4,254,682
Consumer Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance, beginning of period				36,190				45,233	36,190	45,233	42,052
Provision (benefit) charged to expense									4,628	9,367	18,507
Losses charged off									(19,228)	(24,447)	(20,669)
Recoveries									7,091	6,037	5,343
Balance, end of period	28,681			36,190	36,190			45,233	36,190	45,233	42,052	45,233
Individually evaluated for impairment	1,383				1,668							2,903
Collectively evaluated for impairment	27,298				34,522							42,330
Individually evaluated for impairment	39,144				45,436							45,719
Collectively evaluated for impairment	2,357,560				2,544,789							2,638,781
Total Loans and Leases	2,396,704				2,590,225							2,684,500
Commercial Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance, beginning of period				89,533				71,905	89,533	71,905	59,977
Provision (benefit) charged to expense									23,041	23,417	28,662
Losses charged off									(18,220)	(8,147)	(18,360)
Recoveries									4,439	2,358	1,626
Balance, end of period	98,793			89,533	89,533			71,905	89,533	71,905	59,977	71,905
Individually evaluated for impairment	7,824				9,786							7,422
Collectively evaluated for impairment	90,969				79,747							64,483
Individually evaluated for impairment	99,512				72,471							53,037
Collectively evaluated for impairment	6,117,094				5,296,223							4,887,894
Total Loans and Leases	6,216,606				5,368,694							4,940,931
Commercial Real Estate Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance, beginning of period				49,407				47,477	49,407	47,477	41,598
Provision (benefit) charged to expense									12,644	11,040	7,930
Losses charged off									(2,061)	(9,275)	(2,682)
Recoveries									161	165	631
Balance, end of period	60,151			49,407	49,407			47,477	49,407	47,477	41,598	47,477
Individually evaluated for impairment	1,661				272							169
Collectively evaluated for impairment	58,490				49,135							47,308
Individually evaluated for impairment	10,828				11,226							24,755
Collectively evaluated for impairment	4,916,317				4,512,602							4,486,091
Total Loans and Leases	4,927,145				4,523,828							4,510,846
Finance Leases Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance, beginning of period				5,806				6,479	5,806	6,479	5,487
Provision (benefit) charged to expense									(329)	(232)	1,021
Losses charged off									(423)	(558)	(565)
Recoveries									75	117	536
Balance, end of period	5,129			$ 5,806	5,806			$ 6,479	$ 5,806	$ 6,479	$ 5,487	6,479
Individually evaluated for impairment	196				23							9
Collectively evaluated for impairment	4,933				5,783							6,470
Individually evaluated for impairment	6,315				3,325							6,420
Collectively evaluated for impairment	502,082				546,908							629,209
Total Loans and Leases	$ 508,397				$ 550,233							$ 635,629

Loans and Leases (Impaired Loan

Loans and Leases (Impaired Loans And Leases By Class) (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	$ 298,667	$ 274,736
Total Recorded Investment	259,330	246,753
Recorded Investment No Allowance	166,270	141,398
Recorded Investment With Allowance	93,060	105,355
Related Valuation Allowance	15,350	16,554
Residential Portfolio Segment [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	113,575	125,352
Total Recorded Investment	103,531	114,295
Recorded Investment No Allowance	64,899	69,759
Recorded Investment With Allowance	38,632	44,536
Related Valuation Allowance	4,286	4,805
Consumer Portfolio Segment [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance		50,809
Total Recorded Investment		45,436
Recorded Investment No Allowance		34,418
Recorded Investment With Allowance		11,018
Related Valuation Allowance		1,668
Consumer Portfolio Segment [Member] | Home Equity Loan [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	44,654
Total Recorded Investment	39,144
Recorded Investment No Allowance	30,576
Recorded Investment With Allowance	8,568
Related Valuation Allowance	1,383
Commercial Portfolio Segment [Member] | Commercial and Industrial Sector [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	120,165	79,900
Total Recorded Investment	99,287	71,882
Recorded Investment No Allowance	65,724	27,313
Recorded Investment With Allowance	33,563	44,569
Related Valuation Allowance	7,818	9,786
Commercial Portfolio Segment [Member] | Asset Based Loans [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	550	3,272
Total Recorded Investment	225	589
Recorded Investment No Allowance	0	589
Recorded Investment With Allowance	225	0
Related Valuation Allowance	6	0
Commercial Real Estate Portfolio Segment [Member] | Construction Loans [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	0	0
Total Recorded Investment	0	0
Recorded Investment No Allowance	0	0
Recorded Investment With Allowance	0	0
Related Valuation Allowance	0	0
Commercial Real Estate Portfolio Segment [Member] | Real Estate Loan [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	13,355	11,994
Total Recorded Investment	10,828	11,226
Recorded Investment No Allowance	2,125	6,387
Recorded Investment With Allowance	8,703	4,839
Related Valuation Allowance	1,661	272
Finance Leases Portfolio Segment [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	6,368	3,409
Total Recorded Investment	6,315	3,325
Recorded Investment No Allowance	2,946	2,932
Recorded Investment With Allowance	3,369	393
Related Valuation Allowance	$ 196	$ 23

Loans and Leases (Interest Inco

Loans and Leases (Interest Income From Impaired Loans And Leases, By Class) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	$ 253,042	$ 248,054	$ 264,162
Accrued Interest Income	8,313	7,192	8,065
Cash Basis Interest Income	2,086	2,310	2,185
Asset Based Loans [Member]
Financing Receivable, Impaired [Line Items]
Cash Basis Interest Income	0	0	0
Residential Portfolio Segment [Member]
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	108,913	116,859	126,936
Accrued Interest Income	3,781	4,138	4,377
Cash Basis Interest Income	1,106	1,264	1,200
Consumer Portfolio Segment [Member]
Financing Receivable, Impaired [Line Items]
Average Recorded Investment			47,072
Accrued Interest Income			1,361
Cash Basis Interest Income			985
Consumer Portfolio Segment [Member] | Home Equity Loan [Member]
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	42,290	45,578
Accrued Interest Income	1,158	1,323
Cash Basis Interest Income	980	1,046
Commercial Portfolio Segment [Member] | Commercial and Industrial Sector [Member]
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	85,585	62,459	54,708
Accrued Interest Income	3,064	1,095	1,540
Cash Basis Interest Income	0	0	0
Commercial Portfolio Segment [Member] | Asset Based Loans [Member]
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	407	295	0
Accrued Interest Income	0	0	0
Commercial Real Estate Portfolio Segment [Member]
Financing Receivable, Impaired [Line Items]
Average Recorded Investment			28,451
Accrued Interest Income			511
Cash Basis Interest Income	0	0	0
Commercial Real Estate Portfolio Segment [Member] | Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	11,027	17,397
Accrued Interest Income	198	417
Commercial Real Estate Portfolio Segment [Member] | Construction Loans [Member]
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	0	594	3,574
Accrued Interest Income	0	12	92
Cash Basis Interest Income	0	0	0
Finance Leases Portfolio Segment [Member]
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	4,820	4,872	3,421
Accrued Interest Income	112	207	184
Cash Basis Interest Income	$ 0	$ 0	$ 0

Loans and Leases (Commercial, C

Loans and Leases (Commercial, Commercial Real Estate Loans And Equipment Financing Loans Segregated By Risk Rating Exposure) (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Financing Receivable, Impaired [Line Items]
Total Loans and Leases	$ 18,465,489	$ 17,523,858	$ 17,026,588
Commercial Portfolio Segment [Member]
Financing Receivable, Impaired [Line Items]
Total Loans and Leases	6,216,606	5,368,694	4,940,931
Commercial Portfolio Segment [Member] | (1) - (6) Pass [Member]
Financing Receivable, Impaired [Line Items]
Total Loans and Leases	5,781,138	5,048,162
Commercial Portfolio Segment [Member] | (7) Special Mention [Member]
Financing Receivable, Impaired [Line Items]
Total Loans and Leases	206,351	104,594
Commercial Portfolio Segment [Member] | (8) Substandard [Member]
Financing Receivable, Impaired [Line Items]
Total Loans and Leases	222,405	206,883
Commercial Portfolio Segment [Member] | (9) Doubtful [Member]
Financing Receivable, Impaired [Line Items]
Total Loans and Leases	6,712	9,055
Commercial Real Estate Portfolio Segment [Member]
Financing Receivable, Impaired [Line Items]
Total Loans and Leases	4,927,145	4,523,828	4,510,846
Commercial Real Estate Portfolio Segment [Member] | (1) - (6) Pass [Member]
Financing Receivable, Impaired [Line Items]
Total Loans and Leases	4,773,298	4,355,916
Commercial Real Estate Portfolio Segment [Member] | (7) Special Mention [Member]
Financing Receivable, Impaired [Line Items]
Total Loans and Leases	75,338	62,065
Commercial Real Estate Portfolio Segment [Member] | (8) Substandard [Member]
Financing Receivable, Impaired [Line Items]
Total Loans and Leases	78,509	105,847
Commercial Real Estate Portfolio Segment [Member] | (9) Doubtful [Member]
Financing Receivable, Impaired [Line Items]
Total Loans and Leases	0	0
Finance Leases Portfolio Segment [Member]
Financing Receivable, Impaired [Line Items]
Total Loans and Leases	508,397	550,233	$ 635,629
Finance Leases Portfolio Segment [Member] | (1) - (6) Pass [Member]
Financing Receivable, Impaired [Line Items]
Total Loans and Leases	494,585	525,105
Finance Leases Portfolio Segment [Member] | (7) Special Mention [Member]
Financing Receivable, Impaired [Line Items]
Total Loans and Leases	1,303	8,022
Finance Leases Portfolio Segment [Member] | (8) Substandard [Member]
Financing Receivable, Impaired [Line Items]
Total Loans and Leases	12,509	17,106
Finance Leases Portfolio Segment [Member] | (9) Doubtful [Member]
Financing Receivable, Impaired [Line Items]
Total Loans and Leases	$ 0	$ 0

Loans and Leases (Summary Of Th

Loans and Leases (Summary Of The Recorded Investment Of Company's TDRs) (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Financing Receivable, Modifications [Line Items]
Total recorded investment of TDR	$ 230,414	$ 221,404
Specific reserves for TDR included in the balance of ALLL	212,353	199,994	$ 194,320	$ 174,990
Additional funds committed to borrowers in TDR status	3,893	2,736
Performing Financial Instruments [Member]
Financing Receivable, Modifications [Line Items]
Total recorded investment of TDR	138,479	147,113
Nonperforming Financial Instruments [Member]
Financing Receivable, Modifications [Line Items]
Total recorded investment of TDR	91,935	74,291
Troubled Debt Restructures [Member] | Nonperforming Financial Instruments [Member]
Financing Receivable, Modifications [Line Items]
Specific reserves for TDR included in the balance of ALLL	$ 11,930	$ 12,384

Loans and Leases (Information o

Loans and Leases (Information on How Loans and Leases were Modified as a TDR) (Details) $ in Thousands		12 Months Ended
		Dec. 31, 2018USD ($)loan	Dec. 31, 2017USD ($)loan	Dec. 31, 2016USD ($)loan
Financing Receivable, Modifications [Line Items]
Number of Loans and Leases | loan		143	203	175
Post-Modification Recorded Investment | $		$ 66,781	$ 37,636	$ 43,669	[1]
Residential Portfolio Segment [Member] | Extended Maturity [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans and Leases | loan		1	16	17
Post-Modification Recorded Investment | $		$ 20	$ 2,569	$ 2,801	[1]
Residential Portfolio Segment [Member] | Adjusted Interest Rates [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans and Leases | loan		0	2	2
Post-Modification Recorded Investment | $		$ 0	$ 335	$ 528	[1]
Residential Portfolio Segment [Member] | Combination Rate and Maturity [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans and Leases | loan		9	12	13
Post-Modification Recorded Investment | $		$ 947	$ 1,733	$ 1,537	[1]
Residential Portfolio Segment [Member] | other concessions [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans and Leases | loan		21	39	24	[2]
Post-Modification Recorded Investment | $		$ 3,573	$ 6,200	$ 4,090	[1],[2]
Consumer Portfolio Segment [Member] | Extended Maturity [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans and Leases | loan				11
Post-Modification Recorded Investment | $	[1]			$ 484
Consumer Portfolio Segment [Member] | Adjusted Interest Rates [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans and Leases | loan		0	1	0
Post-Modification Recorded Investment | $		$ 0	$ 247	$ 0	[1]
Consumer Portfolio Segment [Member] | Combination Rate and Maturity [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans and Leases | loan				15
Post-Modification Recorded Investment | $	[1]			$ 1,156
Consumer Portfolio Segment [Member] | other concessions [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans and Leases | loan	[2]			52
Post-Modification Recorded Investment | $	[1],[2]			$ 3,131
Commercial Portfolio Segment [Member] | Extended Maturity [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans and Leases | loan				12
Post-Modification Recorded Investment | $	[1]			$ 14,883
Commercial Portfolio Segment [Member] | Adjusted Interest Rates [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans and Leases | loan		0	0	0
Post-Modification Recorded Investment | $		$ 0	$ 0	$ 0	[1]
Commercial Portfolio Segment [Member] | Combination Rate and Maturity [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans and Leases | loan				2
Post-Modification Recorded Investment | $	[1]			$ 648
Commercial Portfolio Segment [Member] | other concessions [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans and Leases | loan	[2]			13
Post-Modification Recorded Investment | $	[1],[2]			$ 1,767
Commercial Real Estate Portfolio Segment [Member] | Extended Maturity [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans and Leases | loan				3
Post-Modification Recorded Investment | $	[1]			$ 4,921
Commercial Real Estate Portfolio Segment [Member] | Adjusted Interest Rates [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans and Leases | loan		0	0	1
Post-Modification Recorded Investment | $	[1]	$ 0	$ 0	$ 237
Commercial Real Estate Portfolio Segment [Member] | Combination Rate and Maturity [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans and Leases | loan				2
Post-Modification Recorded Investment | $	[1]			$ 335
Commercial Real Estate Portfolio Segment [Member] | other concessions [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans and Leases | loan	[2]			1
Post-Modification Recorded Investment | $	[1],[2]			$ 509
Finance Leases Portfolio Segment [Member] | Extended Maturity [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans and Leases | loan		4	0	7
Post-Modification Recorded Investment | $		$ 736	$ 0	$ 6,642	[1]
Home Equity Loan [Member] | Consumer Portfolio Segment [Member] | Extended Maturity [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans and Leases | loan		4	12
Post-Modification Recorded Investment | $		$ 469	$ 976
Home Equity Loan [Member] | Consumer Portfolio Segment [Member] | Combination Rate and Maturity [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans and Leases | loan		6	14
Post-Modification Recorded Investment | $		$ 618	$ 3,469
Home Equity Loan [Member] | Consumer Portfolio Segment [Member] | other concessions [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans and Leases | loan		45	73
Post-Modification Recorded Investment | $		$ 2,812	$ 4,907
Real Estate Loan [Member] | Commercial Real Estate Portfolio Segment [Member] | Extended Maturity [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans and Leases | loan		2	0
Post-Modification Recorded Investment | $		$ 97	$ 0
Real Estate Loan [Member] | Commercial Real Estate Portfolio Segment [Member] | Combination Rate and Maturity [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans and Leases | loan		3	0
Post-Modification Recorded Investment | $		$ 1,485	$ 0
Real Estate Loan [Member] | Commercial Real Estate Portfolio Segment [Member] | other concessions [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans and Leases | loan		1	0
Post-Modification Recorded Investment | $		$ 5,111	$ 0
Commercial and Industrial Sector [Member] | Commercial Portfolio Segment [Member] | Extended Maturity [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans and Leases | loan		12	12
Post-Modification Recorded Investment | $		$ 823	$ 1,233
Commercial and Industrial Sector [Member] | Commercial Portfolio Segment [Member] | Combination Rate and Maturity [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans and Leases | loan		15	18
Post-Modification Recorded Investment | $		$ 8,842	$ 9,592
Commercial and Industrial Sector [Member] | Commercial Portfolio Segment [Member] | other concessions [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans and Leases | loan		20	4
Post-Modification Recorded Investment | $		$ 41,248	$ 6,375
[1]	Post-modification balances approximate pre-modification balances. The aggregate amount of charge-offs as a result of the restructurings was not significant.
[2]	Other includes covenant modifications, forbearance, loans discharged under Chapter 7 bankruptcy, and/or other concessions.

Loans and Leases (Information_2

Loans and Leases (Information on Loans and Leases Modified as TDR within the Previous 12 Months (Details)	12 Months Ended
	Dec. 31, 2018
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Subsequent Default, Number of Contracts	0

Loans and Leases (Investments i

Loans and Leases (Investments in TDRs, Segregated by Risk Rating Exposure) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Financing Receivable, Modifications [Line Items]
Total recorded investment of TDRs	$ 230,414	$ 221,404
Commerial, Commercial Real Estate, Equipment Financing TDR's [Member]
Financing Receivable, Modifications [Line Items]
Total recorded investment of TDRs	87,739	61,673
Commerial, Commercial Real Estate, Equipment Financing TDR's [Member] | (1) - (6) Pass [Member]
Financing Receivable, Modifications [Line Items]
Total recorded investment of TDRs	13,165	8,268
Commerial, Commercial Real Estate, Equipment Financing TDR's [Member] | (7) Special Mention [Member]
Financing Receivable, Modifications [Line Items]
Total recorded investment of TDRs	84	355
Commerial, Commercial Real Estate, Equipment Financing TDR's [Member] | (8) Substandard [Member]
Financing Receivable, Modifications [Line Items]
Total recorded investment of TDRs	67,880	53,050
Commerial, Commercial Real Estate, Equipment Financing TDR's [Member] | (9) Doubtful [Member]
Financing Receivable, Modifications [Line Items]
Total recorded investment of TDRs	$ 6,610	$ 0

Transfers of Financial Assets_2

Transfers of Financial Assets (Reserve for loan repurchases) (Details) - SEC Schedule, 12-09, Reserve, Off-balance Sheet Activity [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Beginning balance	$ 872	$ 790	$ 1,192
(Benefit) provision charged to expense	(160)	100	(303)
Repurchased loans and settlements charged off	(38)	(18)	(99)
Ending balance	$ 674	$ 872	$ 790

Transfers of Financial Assets_3

Transfers of Financial Assets (Loans sold) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Servicing Assets at Fair Value [Line Items]
Net gain on sale	$ 4,424	$ 9,937	$ 14,635
Residential Mortgage [Member]
Servicing Assets at Fair Value [Line Items]
Proceeds from sale	188,025	335,656	438,925
Loans sold with servicing rights retained	166,909	304,788	399,318
Net gain on sale	3,146	6,211	11,629
Ancillary Fee Income Generated by Servicing Financial Assets, Amount	1,544	2,629	3,532
Fair value option adjustment	$ (266)	$ 1,097	(526)
Commercial Loan [Member]
Servicing Assets at Fair Value [Line Items]
Net gain on sale			$ 2,100

Transfers of Financial Assets_4

Transfers of Financial Assets (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Securitization or Asset-backed Financing Arrangement, Financial Asset for which Transfer is Accounted as Sale [Line Items]
Proceeds from loans not originated for sale	$ 1,687	$ 14,679	$ 34,170
Net gain on sale	4,424	9,937	14,635
Residential Mortgage [Member]
Securitization or Asset-backed Financing Arrangement, Financial Asset for which Transfer is Accounted as Sale [Line Items]
Retained servicing rights	2,500,000	2,600,000
Bank servicing fees	1,200	800	1,100
Proceeds from loans not originated for sale	400	7,400	7,600
Net gain on sale	3,146	6,211	11,629
Commercial Loan [Member]
Securitization or Asset-backed Financing Arrangement, Financial Asset for which Transfer is Accounted as Sale [Line Items]
Proceeds from loans not originated for sale	$ 1,300	$ 7,200	26,500
Net gain on sale			$ 2,100

Transfers of Financial Assets S

Transfers of Financial Assets Servicing Assets at Amortized Cost Roll Forward (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Servicing Asset at Amortized Cost, Balance [Roll Forward]
Beginning balance	$ 25,139	$ 24,466	$ 20,698
Additions	4,459	9,249	11,312
Amortization	(8,383)	(8,576)	(7,544)
Ending balance	$ 21,215	$ 25,139	$ 24,466

Premises and Equipment (Summary

Premises and Equipment (Summary of Premises and Equipment) (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2018	Dec. 31, 2016
Property, Plant and Equipment [Abstract]
Land	$ 11,302	$ 10,997
Buildings and improvements	80,646	79,619
Leasehold improvements	82,067	77,669
Fixtures and equipment	76,665	75,219
Data processing and software	234,667	252,723
Total premises and equipment	485,347	496,227
Less: Accumulated depreciation and amortization	(355,346)	(371,377)
Premises and equipment, net	130,001	124,850
Depreciation and amortization	$ 33,100	$ 34,900	$ 30,800

Premises and Equipment (Disclos

Premises and Equipment (Disclosure of Long Lived Assets Held-for-sale) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Movement in Property, Plant and Equipment [Roll Forward]
Beginning balance	$ 144	$ 637
Additions	498	2,006
Write-downs	(137)	(529)
Sales	(414)	(1,970)
Ending balance	$ 91	$ 144

Goodwill and Other Intangible_3

Goodwill and Other Intangible Assets (Gross Carrying Value And Accumulated Amortization Of Other Intangible Assets) (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Finite-Lived Intangible Assets [Line Items]
Goodwill	$ 538,373	$ 538,373
Gross Carrying Amount	43,000	43,000
Accumulated Amortization	(17,236)	(13,389)
Net Carrying Amount	25,764	29,611
Community Banking [Member]
Finite-Lived Intangible Assets [Line Items]
Goodwill	516,560	516,560
HSA Bank [Member]
Finite-Lived Intangible Assets [Line Items]
Goodwill	21,813	21,813
Core Deposits [Member] | HSA Bank [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	22,000	22,000
Accumulated Amortization	(10,842)	(8,610)
Net Carrying Amount	11,158	13,390
Customer Relationships [Member] | HSA Bank [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	21,000	21,000
Accumulated Amortization	(6,394)	(4,779)
Net Carrying Amount	$ 14,606	$ 16,221

Goodwill and Other Intangible_4

Goodwill and Other Intangible Assets (Schedule Of Expected Future Amortization Expense) (Detail) $ in Thousands	Dec. 31, 2018USD ($)
Goodwill and Intangible Assets Disclosure [Abstract]
2,019	$ 3,847
2,020	3,847
2,021	3,847
2,022	3,847
2,023	3,847
Thereafter	$ 6,529

Income Taxes (Income Tax Expens

Income Taxes (Income Tax Expense) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Current:
Federal									$ 58,334	$ 96,364	$ 73,194
State and local									13,409	11,061	5,429
Total current									71,743	107,425	78,623
Deferred:
Federal									8,508	39,568	12,542
State and local									964	(48,642)	5,158
Total deferred									9,472	(9,074)	17,700
Total:
Total federal									66,842	135,932	85,736
Total state and local									14,373	(37,581)	10,587
Income tax expense	$ 26,697	$ 13,700	$ 20,743	$ 20,075	$ 17,029	$ 30,281	$ 29,090	$ 21,951	$ 81,215	$ 98,351	$ 96,323

Income Taxes (Narrative) (Detai

Income Taxes (Narrative) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Operating Loss Carryforwards [Line Items]
Tax Cuts and Jobs Act of 2017, Incomplete Accounting, State and Local tax expense (benefit)			$ 47,500,000
Tax Cuts and Jobs Act of 2017, Incomplete Accounting, State and Local tax expense (benefit), net			37,500,000
Tax Cuts and Jobs Act of 2017, Incomplete Accounting, Federal tax increase related to DTA valuation allowance			10,000,000
Tax Cuts and Jobs Act of 2017, Incomplete Accounting, Provisional SALT DTA benefits			1,800,000
Tax Cuts and Jobs Act of 2017, Incomplete Accounting, DTA measurement Adjustments			31,500,000
Tax Cuts and Jobs Act of 2017, Incomplete Accounting, Federal tax increase related to DTA valuation and SALT Adj			10,600,000
Tax Cuts and Jobs Act of 2017, Incomplete Accounting, Provisional SALT and DTA benefits gross			39,300,000
Tax Cuts and Jobs Act of 2017, Incomplete Accounting, Provisional Federal income tax (benefit)			20,900,000
Tax Cuts and Jobs Act of 2017, Incomplete Accounting, Provisional DTA SALT DTA valuation net benefit 2			28,700,000
Operating loss carryforwards		$ 0	25,100,000	$ 0
Net tax credits		$ 1,200,000	$ 1,600,000	$ 1,000,000
Income tax expense at federal statutory rate		21.00%	35.00%	35.00%
Increase (decrease) in deferred income taxes		$ 3,900,000
Deferred tax expense (benefit)		9,472,000	$ (9,074,000)	$ 17,700,000
Valuation allowance		38,181,000	38,292,000
Valuation allowance increase (decrease)		(111,000)
Net operating loss and credit carry forwards		70,808,000	71,813,000
Unrecognized deferred tax liability for thrift bad-debt reserves		15,200,000
Cumulative taxable temporary differences		58,000,000
Unrecognized tax benefits that would impact effective tax rate		2,300,000	2,800,000	2,500,000
Interest and penalties		0	200,000	$ (200,000)
Accrued interest and penalties related to UTBs		1,800,000	$ 1,900,000
State and Local Jurisdiction [Member]
Operating Loss Carryforwards [Line Items]
Valuation allowance		38,200,000
Deferred Tax Assets, Operating Loss Carryforwards, Subject to Expiration		644,000,000
estimated utilization of capital loss carryforwards [Member]
Operating Loss Carryforwards [Line Items]
Valuation allowance increase (decrease)		(400,000)
Connecticut [Member]
Operating Loss Carryforwards [Line Items]
Net operating loss and credit carry forwards		1,200,000,000
Tax credit carryforwards		500,000
Minimum [Member] | Scenario, Forecast [Member]
Operating Loss Carryforwards [Line Items]
Decrease in UTBs	$ 700,000
Maximum [Member] | Scenario, Forecast [Member]
Operating Loss Carryforwards [Line Items]
Decrease in UTBs	$ 1,800,000
Shareholders' Equity [Member]
Operating Loss Carryforwards [Line Items]
Increase (decrease) in deferred income taxes		$ (13,400,000)

Income Taxes (Schedule of Effec

Income Taxes (Schedule of Effective Income Tax Rate Reconciliation) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Effective Income Tax Rate Reconciliation, Amount [Abstract]
Income tax expense at federal statutory rate									$ 92,743	$ 123,826	$ 106,208
SALT expense, net of federal									11,354	8,189	6,882
Tax-exempt interest income, net									(6,475)	(10,826)	(8,917)
Increase in cash surrender value of life insurance									(3,069)	(5,120)	(5,166)
Non-deductible FDIC deposit insurance premiums									2,215	0
SALT DTA adjustments, net of federal									0	(28,724)	0
Tax Act impacts, net									(10,982)	20,891	0
Other, net									(88)	(3,536)	(2,684)
Income tax expense	$ 26,697	$ 13,700	$ 20,743	$ 20,075	$ 17,029	$ 30,281	$ 29,090	$ 21,951	$ 81,215	$ 98,351	$ 96,323
Effective Income Tax Rate Reconciliation, Percent [Abstract]
Income tax expense at federal statutory rate									21.00%	35.00%	35.00%
SALT expense, net of federal									2.60%	2.30%	2.30%
Tax-exempt interest income, net									(1.50%)	(3.10%)	(2.90%)
Increase in cash surrender value of life insurance									(0.70%)	(1.40%)	(1.70%)
Effective Income Tax Rate Reconciliation, Share-based Compensation, Excess Tax Benefit, Amount									$ (4,483)	$ (6,349)	$ 0
Effective Income Tax Rate Reconciliation, Share-based Compensation, Excess Tax Benefit, Percent									(1.00%)	(1.80%)	0.00%
Non-deductible FDIC deposit insurance premiums									0.50%	0.00%
SALT DTA adjustments, net of federal									0.00%	(8.10%)	0.00%
Tax Act impacts, net									(2.50%)	5.90%	0.00%
Other, net									0.00%	(1.00%)	(1.00%)
Income tax expense and effective tax rate									18.40%	27.80%	31.70%

Income Taxes (Schedule of Defer

Income Taxes (Schedule of Deferred Tax Assets and Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Deferred tax assets:
Allowance for loan and lease losses	$ 54,390	$ 51,203
Net operating loss and credit carry forwards	70,808	71,813
Compensation and employee benefit plans	29,623	25,023
Net unrealized loss on securities available for sale	25,060	9,548
Other	14,388	15,529
Gross deferred tax assets	194,269	173,116
Valuation allowance	(38,181)	(38,292)
Total deferred tax assets, net of valuation allowance	156,088	134,824
Deferred tax liabilities:
Equipment financing leases	28,140	27,955
Deferred Tax Liabilities, Property, Plant and Equipment	10,293	472
Deferred Tax Liabilities, Goodwill and Intangible Assets	9,608	1,018
Goodwill and other intangible assets	6,293	6,364
Mortgage servicing assets	3,604	4,445
Other	1,634	1,940
Gross deferred tax liabilities	59,572	42,194
Deferred tax assets, net	$ 96,516	$ 92,630

Income Taxes (Summary of Positi

Income Taxes (Summary of Positions for which Significant Change in Unrecognized Tax Benefits is Reasonably Possible) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Beginning balance	$ 3,595	$ 3,847	$ 5,094
Additions as a result of tax positions taken during the current year	249	584	613
Additions as a result of tax positions taken during prior years	71	7	0
Reductions as a result of tax positions taken during prior years	(474)	(61)	(625)
Reductions relating to settlements with taxing authorities	(97)	(392)	(693)
Reductions as a result of lapse of statute of limitation periods	(488)	(390)	(542)
Ending balance	$ 2,856	$ 3,595	$ 3,847

Deposits (Summary Of Deposits)

Deposits (Summary Of Deposits) (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Banking and Thrift [Abstract]
Demand	$ 4,162,446	$ 4,191,496
Checking	2,518,472	2,736,952
Health Savings Accounts	5,740,601	5,038,681
Money market	2,100,084	2,209,492
Savings	4,140,696	4,348,700
Time deposits	3,196,546	2,468,408
Total interest-bearing	17,696,399	16,802,233
Total deposits	21,858,845	20,993,729
Time deposits and interest-bearing checking, included in above balances, obtained through brokers	869,003	898,157
Time deposits, included in above balance, that exceed the FDIC limit	555,949	561,512
Demand deposit overdrafts reclassified as loan balances	$ 2,245	$ 2,210

Deposits (Scheduled Maturities

Deposits (Scheduled Maturities Of Time Deposits) (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Banking and Thrift [Abstract]
2,018	$ 2,381,229
2,019	594,754
2,020	143,324
2,021	47,224
2,022	30,015
Thereafter	0
Total time deposits	$ 3,196,546	$ 2,468,408

Borrowings Borrowings - (Narrat

Borrowings Borrowings - (Narrative) (Details) - USD ($) $ in Billions	Dec. 31, 2018	Dec. 31, 2017
Debt Disclosure [Abstract]
Total borrowings	$ 2.6	$ 2.5

Borrowings (Summary Of Securiti

Borrowings (Summary Of Securities Sold Under Agreements To Repurchase And Other Borrowings) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Assets Sold under Agreements to Repurchase [Line Items]
Total securities sold under agreements to repurchase	$ 236,874	$ 588,269
Fed funds purchased	345,000	55,000
Securities sold under agreements to repurchase and other borrowings	581,874	643,269
Original maturity of one year or less [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Total securities sold under agreements to repurchase	236,874	288,269
Original maturity of greater than one year, non-callable [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Total securities sold under agreements to repurchase	$ 0	$ 300,000
Securities Sold under Agreements to Repurchase [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Rate (as a percent)	0.35%	1.66%
Securities Sold under Agreements to Repurchase [Member] | Original maturity of one year or less [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Rate (as a percent)	0.35%	0.17%
Securities Sold under Agreements to Repurchase [Member] | Original maturity of greater than one year, non-callable [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Rate (as a percent)	0.00%	3.10%
Federal Funds Purchased [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Rate (as a percent)	2.52%	1.37%
Federal Funds Purchased and Securities Sold under Agreements to Repurchase [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Rate (as a percent)	1.64%	1.64%

Borrowings (Summary Of Advances

Borrowings (Summary Of Advances Payable To The Federal Home Loan Bank) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Federal Home Loan Bank, Advances, Weighted Average Interest Rate [Abstract]
FHLB advances maturing within 1 year, Weighted-Average Contractual Coupon Rate (as a percent)	2.55%	1.48%
FHLB advances maturing after 1 but within 2 years, Weighted-Average Contractual Coupon Rate (as a percent)	1.73%	1.81%
FHLB advances maturing after 2 but within 3 years, Weighted-Average Contractual Coupon Rate (as a percent)	3.16%	1.73%
FHLB advances maturing after 3 but within 4 years, Weighted-Average Contractual Coupon Rate (as a percent)	0.00%	2.06%
FHLB advances maturing after 4 but within 5 years, Weighted-Average Contractual Coupon Rate (as a percent)	2.95%	0.00%
FHLB advances maturing after 5 years, Weighted-Average Contractual Coupon Rate (as a percent)	2.65%	2.65%
Federal Home Loan Bank, Advances, Weighted Average Interest Rate (as a percent)	2.52%	1.61%
Federal Home Loan Bank, Advances, Maturity, Rolling Year [Abstract]
FHLB advances maturing within 1 year, Total Outstanding	$ 1,403,026	$ 1,150,000
FHLB advances maturing after 1 but within 2 years, Total Outstanding	215,000	103,026
FHLB advances maturing after 2 but within 3 years, Total Outstanding	200,000	215,000
FHLB advances maturing after 3 but within 4 years, Total Outstanding	150	200,000
FHLB advances maturing after 4 but within 5 years, Total Outstanding	242	170
FHLB advances maturing after 5 years, Total Outstanding	8,390	8,909
Advances from Federal Home Loan Banks	1,826,808	1,677,105
Aggregate carrying value of assets pledged as collateral	6,689,761	6,402,066
Remaining borrowing capacity	$ 2,568,664	$ 2,600,624
Previously Reported [Member]
Federal Home Loan Bank, Advances, Weighted Average Interest Rate [Abstract]
FHLB advances maturing after 3 but within 4 years, Weighted-Average Contractual Coupon Rate (as a percent)		4.13%
FHLB advances maturing after 5 years, Weighted-Average Contractual Coupon Rate (as a percent)		1.96%
Federal Home Loan Bank, Advances, Weighted Average Interest Rate (as a percent)		1.85%

Borrowings (Long-Term Debt) (De

Borrowings (Long-Term Debt) (Details) - USD ($)	Dec. 31, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Notes and subordinated debt	$ 227,320,000	$ 227,320,000
Debt issuance cost on senior fixed-rate notes	(691,000)	(826,000)
Long-term debt	$ 226,021,000	$ 225,767,000
Long term debt, variable interest rate, percentage	5.74%	4.55%
London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument [Line Items]
Interest rate spread of LIBOR plus (as a percent)	2.95%
Long-term Debt [Member]
Debt Instrument [Line Items]
Discount on senior fixed-rate notes	$ (608,000)	$ (727,000)
Senior Notes [Member]
Debt Instrument [Line Items]
Debt instrument, stated interest rate, percentage	4.375%
Notes and subordinated debt	$ 150,000,000	150,000,000
Junior Subordinated Debt [Member]
Debt Instrument [Line Items]
Notes and subordinated debt	$ 77,320,000	$ 77,320,000

Shareholders' Equity (Class of

Shareholders' Equity (Class of Stock Disclosure) (Details) - shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Jun. 08, 2011
Class of Stock [Line Items]
Common stock, shares issued	93,686,311	93,680,291
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Treasury Stock Held, beginning balance	1,658,526
Common Stock Outstanding, beginning balance	92,021,765
Restricted share activity	182,553
Stock options exercised	(182,517)
Common stock repurchased	(215,000)
Class of Warrant or Right, Number of Securities Called by Warrants or Rights	6,020		3,282,276
Treasury Stock Held, ending balance	1,508,456
Common Stock Outstanding, ending balance	92,177,855
Series F Preferred Stock [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares, beginning balance	6,000
Stock Issued During Period, Shares, New Issues	0
Shares, ending balance	6,000
Common Stock [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares, beginning balance	93,680,291
Class of Warrant or Right, Number of Securities Called by Warrants or Rights	6,020
Treasury Stock [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Treasury Stock Held, beginning balance	1,658,526
Restricted share activity	(182,553)
Stock options exercised	(182,517)
Common stock repurchased	(215,000)

Shareholders' Equity (Narrative

Shareholders' Equity (Narrative) (Details) - USD ($)	Dec. 04, 2012	Dec. 31, 2018	Dec. 31, 2017	Dec. 06, 2012	Jun. 08, 2011
Class of Stock [Line Items]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights		6,020			3,282,276
Common stock par value (in usd per share)		$ 0.01	$ 0.01		$ 0.01
Exercise price of warrants or rights (in usd per share)					$ 18.28
Warrants exercised in cashless exchange		8,647
Warrants outstanding (in shares)		0	8,752
Preferred Stock, Par or Stated Value Per Share		$ 0.01	$ 0.01
Common Stock [Member]
Class of Stock [Line Items]
Stock repurchase program, authorized amount				$ 100,000,000
Treasury stock acquired, average cost per share (in usd per share)		$ 56.55
Stock repurchase program, remaining authorized repurchase amount		$ 91,700,000
Class of Warrant or Right, Number of Securities Called by Warrants or Rights		6,020
Series E Preferred Stock [Member]
Class of Stock [Line Items]
Preferred stock, dividend rate (as a percent)	5.25%
Preferred Stock, Par or Stated Value Per Share	$ 0.01
Preferred stock, liquidation preference per share (in usd per share)	$ 25,000
Depository shares, issued	6,000,000
Depository share, par or stated value per share (in usd per share)	$ 25

Accumulated Other Comprehensi_3

Accumulated Other Comprehensive Loss, Net of Tax (Schedule of Accumulated Other Comprehensive Loss) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Accumulated Other Comprehensive Income (Loss) [Line Items]
Cumulative Effect of New Accounting Principle in Period of Adoption	$ (1,373)	$ 0
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	2,701,958	2,527,012	$ 2,413,960
Other comprehensive (loss) income, net of tax	(39,121)	1,110	1,113
Ending Balance	2,886,515	2,701,958	2,527,012
Available For Sale and Transferred Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Cumulative Effect of New Accounting Principle in Period of Adoption	(4,881)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	(43,427)	(7,590)	(8,901)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	(27,947)	(15,476)	(6,407)
Amounts reclassified from accumulated other comprehensive loss	0	0	(168)
Other comprehensive (loss) income, net of tax	(43,427)	(7,590)	(9,069)
Ending Balance	(71,374)	(27,947)	(15,476)
Derivative Instruments [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Cumulative Effect of New Accounting Principle in Period of Adoption	(2,513)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	208	181	825
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	(15,016)	(17,068)	(22,980)
Amounts reclassified from accumulated other comprehensive loss	5,495	4,384	5,087
Other comprehensive (loss) income, net of tax	5,703	4,565	5,912
Ending Balance	(9,313)	(15,016)	(17,068)
Defined Benefit Pension and Postretirement Benefit Plans [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Cumulative Effect of New Accounting Principle in Period of Adoption	(8,254)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	(7,122)	98	(232)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	(48,568)	(44,449)	(48,719)
Amounts reclassified from accumulated other comprehensive loss	5,725	4,037	4,502
Other comprehensive (loss) income, net of tax	(1,397)	4,135	4,270
Ending Balance	(49,965)	(48,568)	(44,449)
AOCI Attributable to Parent [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Cumulative Effect of New Accounting Principle in Period of Adoption	(15,648)	(15,648)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	(50,341)	(7,311)	(8,308)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	(91,531)	(76,993)	(78,106)
Amounts reclassified from accumulated other comprehensive loss	11,220	8,421	9,421
Other comprehensive (loss) income, net of tax	(39,121)	1,110	1,113
Ending Balance	$ (130,652)	$ (91,531)	$ (76,993)

Accumulated Other Comprehensi_4

Accumulated Other Comprehensive Loss, Net of Tax (Schedule of Reclassifications from AOCI) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Debt Securities, Available-for-sale, Realized Gain (Loss)									$ 0	$ 0	$ 414
Impairment loss on securities recognized in earnings									0	(126)	(149)
Income before income tax expense	$ 125,535	$ 113,373	$ 102,425	$ 100,300	$ 86,922	$ 94,777	$ 90,669	$ 81,422	441,633	353,790	303,450
Income tax expense	$ (26,697)	$ (13,700)	$ (20,743)	$ (20,075)	$ (17,029)	$ (30,281)	$ (29,090)	$ (21,951)	(81,215)	(98,351)	(96,323)
Earnings applicable to common shareholders									351,703	246,831	198,423
Accumulated Net Investment Gain (Loss) Including Portion Attributable to Noncontrolling Interest [Member] | Reclassification out of accumualted comprehensive income [Member]
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Debt Securities, Available-for-sale, Realized Gain (Loss)									0	0	414
Impairment loss on securities recognized in earnings									0	0	(149)
Income before income tax expense									0	0	265
Available For Sale and Transferred Securities [Member]
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Net of tax									0	0	168
Available For Sale and Transferred Securities [Member] | Reclassification out of accumualted comprehensive income [Member]
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Income tax expense									0	0	97
Earnings applicable to common shareholders									0	0	168
Derivative Instruments [Member]
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Net of tax									(5,495)	(4,384)	(5,087)
Derivative Instruments [Member] | Reclassification out of accumualted comprehensive income [Member]
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Income tax expense									1,930	2,776	2,933
Earnings applicable to common shareholders									(5,495)	(4,384)	(5,087)
Interest expense									(7,425)	(7,160)	(8,020)
Accumulated Defined Benefit Plans Adjustment, Net Unamortized Gain (Loss) [Member]
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Total before tax									(7,708)	(6,612)	(7,126)	[1]
Accumulated Defined Benefit Plans Adjustment, Net Prior Service Cost (Credit) [Member]
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Total before tax									0	0	(14)	[1]
Defined benefit pension and postretirement benefit plans [Member]
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Total before tax									(7,708)	(6,612)	(7,140)
Tax benefit									1,983	2,575	2,638
Net of tax									$ (5,725)	$ (4,037)	$ (4,502)
[1]	These accumulated other comprehensive income components are included in the computation of net periodic benefit cost (see Note 17: Retirement Benefit Plans for further details).

Accumulated Other Comprehensi_5

Accumulated Other Comprehensive Loss, Net of Tax (Schedule of Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Available-for-sale securities:
Net unrealized loss during the period	$ (58,792)	$ (12,423)	$ (14,113)
Reclassification for net gain included in net income	0	0	(414)
Net non-credit other-than-temporary impairment	0	0	149
Total available-for-sale securities	(58,792)	(12,423)	(14,378)
Derivative instruments:
Net unrealized gain during the period	280	291	1,331
Reclassification adjustment for net loss included in net income	7,425	7,160	8,020
Total derivative instruments	7,705	7,451	9,351
Defined benefit pension and other postretirement benefit plans:
Current year actuarial loss	(9,600)	155	(368)
Reclassification adjustment for amortization of net loss included in net income	7,708	6,612	7,126
Reclassification adjustment for prior service cost included in net income	0	0	14
Total defined benefit pension and postretirement benefit plans	(1,892)	6,767	6,772
Available-for-sale securities:
Net unrealized loss during the period	15,365	4,833	5,212
Reclassification for net gain included in net income	0	0	152
Net non-credit other-than-temporary impairment	0	0	(55)
Total available-for-sale securities	15,365	4,833	5,309
Derivative instruments:
Net unrealized gain during the period	(72)	(110)	(506)
Reclassification adjustment for net loss included in net income	(1,930)	(2,776)	(2,933)
Total derivative instruments	(2,002)	(2,886)	(3,439)
Defined benefit pension and other postretirement benefit plans:
Current year actuarial loss	2,478	(57)	136
Reclassification adjustment for amortization of net loss included in net income	(1,983)	(2,575)	(2,633)
Reclassification adjustment for prior service cost included in net income	0	0	(5)
Total defined benefit pension and postretirement benefit plans	495	(2,632)	(2,502)
Available-for-sale securities:
Net unrealized loss during the period	(43,427)	(7,590)	(8,901)
Reclassification for net gain included in net income	0	0	(262)
Net non-credit other-than-temporary impairment	0	0	94
Total available-for-sale securities	(43,427)	(7,590)	(9,069)
Derivative instruments:
Net unrealized gains on derivative instruments	208	181	825
Reclassification adjustment for net loss included in net income	5,495	4,384	5,087
Total derivative instruments	5,703	4,565	5,912
Defined benefit pension and other postretirement benefit plans:
Current year actuarial loss	(7,122)	98	(232)
Reclassification adjustment for amortization of net loss included in net income	5,725	4,037	4,493
Reclassification adjustment for prior service cost included in net income	0	0	9
Total defined benefit pension and postretirement benefit plans	(1,397)	4,135	4,270
Other Comprehensive Income (Loss), Pre-Tax Amount	(52,979)	1,795	1,745
Other Comprehensive Income (Loss), Tax Benefit (Expense)	13,858	(685)	(632)
Other comprehensive (loss) income, net of tax	$ (39,121)	$ 1,110	$ 1,113

Regulatory Matters (Information

Regulatory Matters (Information On The Capital Ratios) (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Common Equity Tier One Capital	$ 2,284,978	$ 2,093,116
Common Equity Tier One Capital Required for Capital Adequacy	$ 898,972	$ 845,389
Common Equity Tier One Capital Ratio	11.44%	11.14%
Common Equity Tier One Capital Required to be Well-Capitalized	$ 1,298,514	$ 1,221,118
Total risk-based capital, Actual Amount	$ 2,722,194	$ 2,517,848
Total risk-based capital, Actual Ratio	13.63%	13.40%
Total risk-based capital, Capital Requirements, Minimum Amount	$ 1,598,172	$ 1,502,914
Total risk-based capital, Capital Requirements, Minimum Ratio	8.00%	8.00%
Total risk-based capital, Capital Requirements, Well Capitalized Amount	$ 1,997,715	$ 1,878,643
Total risk-based capital, Capital Requirements, Well Capitalized Ratio	10.00%	10.00%
Tier 1 risk-based capital, Actual Amount	$ 2,430,015	$ 2,238,172
Tier 1 risk-based capital, Actual Ratio	12.16%	11.91%
Tier 1 risk-based capital, Capital Requirements, Minimum Amount	$ 1,198,629	$ 1,127,186
Tier 1 risk-based capital, Capital Requirements, Minimum Ratio	6.00%	6.00%
Tier 1 risk-based capital, Capital Requirements, Well Capitalized Amount	$ 1,598,172	$ 1,502,914
Tier 1 risk-based capital, Capital Requirements, Well Capitalized Ratio	8.00%	8.00%
Tier 1 leverage capital, Actual Amount	$ 2,430,015	$ 2,238,172
Tier 1 leverage capital, Actual Ratio	9.02%	8.63%
Tier 1 leverage capital, Capital Requirements, Minimum Amount	$ 1,077,303	$ 1,036,817
Tier 1 leverage capital, Capital Requirements, Minimum Ratio	4.00%	4.00%
Tier 1 leverage capital, Capital Requirements, Well Capitalized Amount	$ 1,346,628	$ 1,296,021
Tier 1 leverage capital, Capital Requirements, Well Capitalized Ratio	5.00%	5.00%
Subsidiaries [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Common Equity Tier One Capital	$ 2,170,566	$ 2,114,224
Common Equity Tier One Capital Required for Capital Adequacy	$ 898,317	$ 844,693
Common Equity Tier One Capital Ratio	10.87%	11.26%
Common Equity Tier One Capital Required to be Well-Capitalized	$ 1,297,569	$ 1,220,113
Total risk-based capital, Actual Amount	$ 2,385,425	$ 2,316,580
Total risk-based capital, Actual Ratio	11.95%	12.34%
Total risk-based capital, Capital Requirements, Minimum Amount	$ 1,597,008	$ 1,501,677
Total risk-based capital, Capital Requirements, Minimum Ratio	8.00%	8.00%
Total risk-based capital, Capital Requirements, Well Capitalized Amount	$ 1,996,260	$ 1,877,097
Total risk-based capital, Capital Requirements, Well Capitalized Ratio	10.00%	10.00%
Tier 1 risk-based capital, Actual Amount	$ 2,170,566	$ 2,114,224
Tier 1 risk-based capital, Actual Ratio	10.87%	11.26%
Tier 1 risk-based capital, Capital Requirements, Minimum Amount	$ 1,197,756	$ 1,126,258
Tier 1 risk-based capital, Capital Requirements, Minimum Ratio	6.00%	6.00%
Tier 1 risk-based capital, Capital Requirements, Well Capitalized Amount	$ 1,597,008	$ 1,501,677
Tier 1 risk-based capital, Capital Requirements, Well Capitalized Ratio	8.00%	8.00%
Tier 1 leverage capital, Actual Amount	$ 2,170,566	$ 2,114,224
Tier 1 leverage capital, Actual Ratio	8.06%	8.14%
Tier 1 leverage capital, Capital Requirements, Minimum Amount	$ 1,076,712	$ 1,038,442
Tier 1 leverage capital, Capital Requirements, Minimum Ratio	4.00%	4.00%
Tier 1 leverage capital, Capital Requirements, Well Capitalized Amount	$ 1,345,889	$ 1,298,052
Tier 1 leverage capital, Capital Requirements, Well Capitalized Ratio	5.00%	5.00%
Risk Based Capital Required for Capital Adequacy to Risk Weighted Assets [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Common Equity Tier One Capital Ratio	4.50%	4.50%
Risk Based Capital Required for Capital Adequacy to Risk Weighted Assets [Member] | Subsidiaries [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Common Equity Tier One Capital Ratio	4.50%	4.50%
Risk Based Capital Required to be Well Capitalized to Risk Weighted Assets [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Common Equity Tier One Capital Ratio	6.50%	6.50%
Risk Based Capital Required to be Well Capitalized to Risk Weighted Assets [Member] | Subsidiaries [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Common Equity Tier One Capital Ratio	6.50%	6.50%

Regulatory Matters Regulatory M

Regulatory Matters Regulatory Matters - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Cash dividends paid to parent company	$ 290	$ 120
Subsidiaries [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Cash held by Bank	$ 81.2	$ 82.3

Earnings Per Common Share (Earn

Earnings Per Common Share (Earnings Per Share Basic And Diluted) (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Earnings Per Share Reconciliation [Abstract]
Net income	$ 98,838	$ 99,673	$ 81,682	$ 80,225	$ 69,893	$ 64,496	$ 61,579	$ 59,471	$ 360,418	$ 255,439	$ 207,127
Less: Preferred stock dividends									7,853	8,184	8,096
Net income available to common shareholders, basic	$ 96,666	$ 97,460	$ 79,489	$ 78,083	$ 67,710	$ 62,426	$ 59,485	$ 57,342	352,565	247,255	199,031
Net income available to common shareholders, diluted									352,565	247,255	199,031
Less: Earnings applicable to participating securities, basic									862	424	608
Less: Earnings applicable to participating securities, diluted									862	424	608
Earnings applicable to common shareholders									351,703	246,831	198,423
Earnings applicable to common shareholders, diluted									$ 351,703	$ 246,831	$ 198,423
Shares:
Weighted-average common shares outstanding - basic									91,930	91,965	91,367
Effect of dilutive securities:
Stock options and restricted stock (in shares)									292	385	461
Warrants (in shares)									5	6	28
Weighted Average Number of Shares Outstanding, Diluted									92,227	92,356	91,856
Earnings per common share:
Earnings per common share, Basic (in dollars per share)	$ 1.05	$ 1.06	$ 0.87	$ 0.85	$ 0.74	$ 0.68	$ 0.65	$ 0.62	$ 3.83	$ 2.68	$ 2.17
Earnings per common share, Diluted (in dollars per share)	$ 1.05	$ 1.06	$ 0.86	$ 0.85	$ 0.73	$ 0.67	$ 0.64	$ 0.62	$ 3.81	$ 2.67	$ 2.16

Earnings Per Common Share (Sche

Earnings Per Common Share (Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share) (Details) - shares shares in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Employee Stock Option [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, shares	0	0	41
Restricted Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, shares	47	58	125

Derivative Financial Instrume_3

Derivative Financial Instruments (Schedule of fair value of derivative instruments) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Subject to a Master Netting Agreement	$ 9,928	$ 8,992
Derivative Asset, Collateral, Obligation to Return Cash, Offset	39,500
Derivative Asset	2,497	43
Derivative Liability, Fair Value, Subject to a Master Netting Agreement	2,566	2,387
Derivative Liability	71	142
Subject to and not subject to Master Netting Agreements [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Notional Amount	4,859,561	4,613,183
Derivative Asset, Fair Value, Gross derivative instruments, before netting	46,278	32,515
Derivative Asset, Fair Value, Amount Offset Against Collateral	2,495	2,245
Derivative Asset, Collateral, Obligation to Return Cash, Offset	4,936	6,704
Derivative Asset	38,847	23,566
Derivative Liability, Notional Amount	3,801,586	3,056,079
Derivative Liability, Fair Value, Gross derivative instruments, before netting	39,010	28,423
Derivative Liability, Fair Value, Amount Offset Against Collateral	2,495	2,245
Derivative Liability, Collateral, Right to Reclaim Cash, Offset	0	0
Derivative Liability	36,515	26,178
Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Subject to a Master Netting Agreement	3,050	2,770
Derivative Asset, Fair Value, Amount Offset Against Collateral	88	91
Derivative Asset, Collateral, Obligation to Return Cash, Offset	567	2,679
Derivative Asset	2,395	0
Derivative Liability, Fair Value, Subject to a Master Netting Agreement	0	0
Derivative Liability, Fair Value, Amount Offset Against Collateral	0	0
Derivative Liability, Collateral, Right to Reclaim Cash, Offset	0	0
Derivative Liability	0	0
Designated as Hedging Instrument [Member] | Derivatives Subject to Master Netting Arrangement or Similar Arrangement [Member] | Interest Rate Contract [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Notional Amount	325,000	325,000
Derivative Asset, Fair Value, Subject to a Master Netting Agreement	3,050	2,770
Derivative Liability, Notional Amount	0	0
Derivative Liability, Fair Value, Subject to a Master Netting Agreement	0	0
Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Subject to a Master Netting Agreement	6,878	6,222
Derivative Asset, Fair Value, Amount Offset Against Collateral	2,407	2,154
Derivative Asset, Collateral, Obligation to Return Cash, Offset	4,369	4,025
Derivative Asset	102	43
Derivative Liability, Fair Value, Subject to a Master Netting Agreement	2,566	2,387
Derivative Liability, Fair Value, Amount Offset Against Collateral	2,495	2,245
Derivative Liability, Collateral, Right to Reclaim Cash, Offset	0	0
Derivative Liability	71	142
Not Designated as Hedging Instrument [Member] | CME [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Notional Amount	1,900,000	1,900,000
Derivative Liability, Notional Amount	1,100,000	595,000
Not Designated as Hedging Instrument [Member] | Derivatives Subject to Master Netting Arrangement or Similar Arrangement [Member] | Interest Rate Contract [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Notional Amount	2,767,518	2,791,760
Derivative Asset, Fair Value, Subject to a Master Netting Agreement	6,570	5,977
Derivative Liability, Notional Amount	1,276,109	721,048
Derivative Liability, Fair Value, Subject to a Master Netting Agreement	2,012	1,968
Not Designated as Hedging Instrument [Member] | Derivatives Subject to Master Netting Arrangement or Similar Arrangement [Member] | Mortgage Banking Derivatives [Member] | RPA-Out [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Notional Amount	13,599	28,497
Derivative Asset, Fair Value, Subject to a Master Netting Agreement	226	421
Not Designated as Hedging Instrument [Member] | Derivatives Subject to Master Netting Arrangement or Similar Arrangement [Member] | Mortgage Banking Derivatives [Member] | RPA-In [Member]
Derivatives, Fair Value [Line Items]
Derivative Liability, Notional Amount	17,000	39,230
Derivative Liability, Fair Value, Subject to a Master Netting Agreement	293	110
Not Designated as Hedging Instrument [Member] | Derivatives Subject to Master Netting Arrangement or Similar Arrangement [Member] | Other [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Notional Amount	11,952	7,914
Derivative Asset, Fair Value, Subject to a Master Netting Agreement	308	258
Derivative Liability, Notional Amount	43,097	30,328
Derivative Liability, Fair Value, Subject to a Master Netting Agreement	553	419
Not Designated as Hedging Instrument [Member] | Derivatives Not Subject to Master Netting Arrangement or Similar Arrangement [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Notional Amount	4,534,561	4,288,183
Derivative Asset, Fair Value, Not Subject to Master Netting Agreement	43,228	29,745
Derivative Liability, Notional Amount	3,801,586	3,056,079
Derivative Liability, Fair Value, Not Subject to Master Netting Agreement	39,010	28,423
Not Designated as Hedging Instrument [Member] | Derivatives Not Subject to Master Netting Arrangement or Similar Arrangement [Member] | Interest Rate Contract [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Notional Amount	1,668,012	1,366,299
Derivative Asset, Fair Value, Not Subject to Master Netting Agreement	35,635	23,009
Derivative Liability, Notional Amount	2,367,876	2,146,518
Derivative Liability, Fair Value, Not Subject to Master Netting Agreement	36,017	25,631
Not Designated as Hedging Instrument [Member] | Derivatives Not Subject to Master Netting Arrangement or Similar Arrangement [Member] | RPA's [Member] | RPA-Out [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Notional Amount	64,974	93,713
Derivative Asset, Fair Value, Not Subject to Master Netting Agreement	39	80
Not Designated as Hedging Instrument [Member] | Derivatives Not Subject to Master Netting Arrangement or Similar Arrangement [Member] | RPA's [Member] | RPA-In [Member]
Derivatives, Fair Value [Line Items]
Derivative Liability, Notional Amount	96,296	116,882
Derivative Liability, Fair Value, Not Subject to Master Netting Agreement	81	111
Not Designated as Hedging Instrument [Member] | Derivatives Not Subject to Master Netting Arrangement or Similar Arrangement [Member] | Other [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Notional Amount	8,506	0
Derivative Asset, Fair Value, Not Subject to Master Netting Agreement	450	0
Derivative Liability, Notional Amount	1,208	2,073
Derivative Liability, Fair Value, Not Subject to Master Netting Agreement	54	$ 184
Loan Origination Commitments [Member]
Derivatives, Fair Value [Line Items]
Other Commitment	17,000
Interest Rate Lock Commitments [Member]
Derivatives, Fair Value [Line Items]
Other Commitment	$ 6,700

Derivative Financial Instrume_4

Derivative Financial Instruments (Schedule of the changes in the fair value of non-hedge accounting derivatives) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Derivative [Line Items]
Total not designated as hedging instruments (2)		$ 114
Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Total not designated as hedging instruments (2)	$ 12,389		$ 9,793
Interest Rate Contract [Member] | Operating Expense [Member] | Designated as Hedging Instrument [Member]
Derivative [Line Items]
Total not designated as hedging instruments (2)	6,557	7,885	9,762
Interest Rate Contract [Member] | Operating Expense [Member] | Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Total not designated as hedging instruments (2)	10,376	2,702	8,668
RPA's [Member] | Operating Expense [Member] | Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Total not designated as hedging instruments (2)	99	242	(361)
Mortgage Banking Derivatives [Member] | Operating Expense [Member] | Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Total not designated as hedging instruments (2)	(378)	(2,062)	1,553
Other [Member] | Operating Expense [Member] | Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Total not designated as hedging instruments (2)	$ 2,292	$ (768)	$ (67)

Derivative Financial Instrume_5

Derivative Financial Instruments (AOCL Cash Flow Derivatives - Narrative) (Details) - Cash Flow Hedging [Member] $ in Millions	12 Months Ended
	Dec. 31, 2018USD ($)
Derivative [Line Items]
Cash flow hedge to be reclassified from AOCL as an increase to interest expense	$ (3.9)
Remaining unamortized loss on termination of cash flow hedges	8.7
Designated as Hedging Instrument [Member]
Derivative [Line Items]
Cash flow hedge to be reclassified from AOCL as an increase to interest expense	$ 0.1

Derivative Financial Instrume_6

Derivative Financial Instruments (Schedule of offsetting financial assets and liabilities for non-customer derivative positions) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Derivative [Line Items]
Derivative Asset, Gross Amount	$ 9,928	$ 8,992
Derivative Asset, Collateral, Obligation to Return Cash, Offset	39,500
Derivative Asset, Net Amount	2,497	43
Derivative Liability, Gross Amount	2,566	2,387
Derivative Liability, Net Amount	71	142
Subject to and not subject to Master Netting Agreements [Member]
Derivative [Line Items]
Derivative Asset, Fair Value, Amount Offset Against Collateral	2,495	2,245
Derivative Asset, Collateral, Obligation to Return Cash, Offset	4,936	6,704
Derivative Asset, Net Amount	38,847	23,566
Derivative Liability, Fair Value, Amount Offset Against Collateral	2,495	2,245
Derivative Liability, Collateral, Right to Reclaim Cash, Offset	0	0
Derivative Liability, Net Amount	36,515	26,178
Designated as Hedging Instrument [Member]
Derivative [Line Items]
Derivative Asset, Gross Amount	3,050	2,770
Derivative Asset, Fair Value, Amount Offset Against Collateral	88	91
Derivative Asset, Collateral, Obligation to Return Cash, Offset	567	2,679
Derivative Asset, Net Amount	2,395	0
Derivative Liability, Gross Amount	0	0
Derivative Liability, Fair Value, Amount Offset Against Collateral	0	0
Derivative Liability, Collateral, Right to Reclaim Cash, Offset	0	0
Derivative Liability, Net Amount	0	0
Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Derivative Asset, Gross Amount	6,878	6,222
Derivative Asset, Fair Value, Amount Offset Against Collateral	2,407	2,154
Derivative Asset, Collateral, Obligation to Return Cash, Offset	4,369	4,025
Derivative Asset, Net Amount	102	43
Derivative Liability, Gross Amount	2,566	2,387
Derivative Liability, Fair Value, Amount Offset Against Collateral	2,495	2,245
Derivative Liability, Collateral, Right to Reclaim Cash, Offset	0	0
Derivative Liability, Net Amount	$ 71	$ 142

Derivative Financial Instrume_7

Derivative Financial Instruments (Counterparty Credit Risk) (Narrative) (Details) $ in Millions	Dec. 31, 2018USD ($)
Derivative [Line Items]
Net margin collateral posted	$ (5.6)
Initial margin	39.5
Maximum exposure	35.6
Valuation, Market Approach [Member]
Derivative [Line Items]
Maximum exposure	35.5
Over the Counter [Member]
Derivative [Line Items]
Net margin collateral posted	(5.6)
Exchange Cleared [Member]
Derivative [Line Items]
Net margin collateral posted	$ 28.3

Fair Value Measurements (Narrat

Fair Value Measurements (Narrative) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total credit-related financial instruments with off-balance sheet risk	$ 6,050,806	$ 5,806,789
Rabbi Trust [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other Assets, Fair Value Disclosure	1,900
Alternative investments [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Unrealized Gain (Loss) on Investments	(100)
Total credit-related financial instruments with off-balance sheet risk	2,700
Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Book value of other real estate owned (OREO) and repossessed assets	6,900
Fair Value, Measurements, Nonrecurring [Member] | Alternative investments [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other Assets, Fair Value Disclosure	$ 4,900

Fair Value Measurements (Fair V

Fair Value Measurements (Fair Value Assets And Liabilities Measured On Recurring Basis) (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	$ 2,898,730	$ 2,638,037
Derivative asset	2,497	43
Loans Held-for-sale, Fair Value Disclosure	7,908	20,888
Derivative liability	71	142
Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	2,898,730	2,638,037
Alternative Investment	2,563	7,460
Assets, Fair Value Disclosure	2,959,786	2,703,701
Derivative liability	39,010	28,423
Fair Value, Measurements, Recurring [Member] | Derivative instruments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative asset	46,278	32,515
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	7,550	1,247
Alternative Investment	0	0
Assets, Fair Value Disclosure	12,615	6,306
Derivative liability	588	587
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Derivative instruments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative asset	758	258
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	2,891,180	2,636,790
Alternative Investment	0
Assets, Fair Value Disclosure	2,944,608	2,689,935
Derivative liability	38,422	27,836
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Derivative instruments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative asset	45,520	32,257
Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Alternative Investment		7,460
Assets, Fair Value Disclosure		7,460
Fair Value, Measurements, Recurring [Member] | Fair Value Measured at Net Asset Value Per Share [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Alternative Investment	2,563	0
Assets, Fair Value Disclosure	2,563	0
Derivative liability		0
Fair Value, Measurements, Recurring [Member] | Fair Value Measured at Net Asset Value Per Share [Member] | Derivative instruments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative asset		0
Investments held In Rabbi Trust [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other Assets, Fair Value Disclosure	4,307	4,801
Investments held In Rabbi Trust [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other Assets, Fair Value Disclosure	4,307	4,801
Investments held In Rabbi Trust [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value Measured at Net Asset Value Per Share [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other Assets, Fair Value Disclosure		0
Loan Origination Commitments [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans Held-for-sale, Fair Value Disclosure	7,908	20,888
Loan Origination Commitments [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans Held-for-sale, Fair Value Disclosure	0	0
Loan Origination Commitments [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans Held-for-sale, Fair Value Disclosure	7,908	20,888
Loan Origination Commitments [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value Measured at Net Asset Value Per Share [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans Held-for-sale, Fair Value Disclosure	0
US Treasury Bill Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	7,550	1,247
US Treasury Bill Securities [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	7,550	1,247
US Treasury Bill Securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	7,550	1,247
Corporate Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	50,579	56,622
Corporate Debt Securities [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	50,579	56,622
Corporate Debt Securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	50,579	56,622
Trust Preferred Securities Single Issuers [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	0	7,050
Trust Preferred Securities Single Issuers [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale		7,050
Trust Preferred Securities Single Issuers [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale		7,050
Collateralized loan obligations (CLO) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	112,771	209,851
Collateralized loan obligations (CLO) [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	112,771	209,851
Collateralized loan obligations (CLO) [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	112,771	209,851
Commercial Mortgage Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	445,581	361,067
Commercial Mortgage Backed Securities [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	445,581	361,067
Commercial Mortgage Backed Securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	0	0
Commercial Mortgage Backed Securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	445,581	361,067
Commercial Mortgage Backed Securities [Member] | Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	0	0
Commercial Mortgage Backed Securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value Measured at Net Asset Value Per Share [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	0	0
Agency commercial mortgage-backed securities (agency CMBS) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	566,237	588,026
Agency commercial mortgage-backed securities (agency CMBS) [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	566,237	588,026
Agency commercial mortgage-backed securities (agency CMBS) [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	0	0
Agency commercial mortgage-backed securities (agency CMBS) [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	566,237	588,026
Agency commercial mortgage-backed securities (agency CMBS) [Member] | Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	0	0
Agency commercial mortgage-backed securities (agency CMBS) [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value Measured at Net Asset Value Per Share [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	0	0
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	1,481,089	1,107,841
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	1,481,089	1,107,841
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	1,481,089	1,107,841
Collateralized Mortgage Obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	234,923	306,333
Collateralized Mortgage Obligations [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	234,923	306,333
Collateralized Mortgage Obligations [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	$ 234,923	$ 306,333

Fair Value Measurements Fair Va

Fair Value Measurements Fair Value Options (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair Value, Option, Loans Held as Assets, Aggregate Difference	$ (319)	$ 542
Loans Held-for-sale, Fair Value Disclosure	7,908	20,888
loans held for sale [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Loans and Leases Receivable, Gross, Consumer, Real Estate	$ 8,227	$ 20,346

Fair Value Measurements (Summar

Fair Value Measurements (Summary Of Estimated Fair Values Of Significant Financial Instruments) (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans Held-for-sale, Fair Value Disclosure	$ 7,908	$ 20,888
Mortgage servicing assets, Carrying Amount	21,215	25,139	$ 24,466	$ 20,698
Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans Held-for-sale, Fair Value Disclosure	0	0
Loans and leases, net	18,253,136	17,323,864
Securities sold under agreements to repurchase and other borrowings	581,874	643,269
FHLB advances	1,826,808	1,677,105
Long-term debt	226,021	225,767
Fair Value, Measurements, Nonrecurring [Member] | Deposits other than time deposits [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Deposits	18,662,299	18,525,321
Fair Value, Measurements, Nonrecurring [Member] | Time Deposits [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Deposits	3,196,546	2,468,408
Fair Value, Measurements, Nonrecurring [Member] | Securities held-to-maturity [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held-to-maturity investment securities	4,325,420	4,487,392
Fair Value, Measurements, Nonrecurring [Member] | Residential Mortgage [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage servicing assets, Carrying Amount	21,215	25,139
Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value Measurement [Member] | Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans Held-for-sale, Fair Value Disclosure	0	0
Securities sold under agreements to repurchase and other borrowings	581,874	644,084
FHLB advances	1,826,381	1,678,070
Long-term debt	229,306	234,359
Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value Measurement [Member] | Fair Value, Measurements, Nonrecurring [Member] | Deposits other than time deposits [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Deposits	18,662,299	18,525,321
Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value Measurement [Member] | Fair Value, Measurements, Nonrecurring [Member] | Time Deposits [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Deposits	3,175,948	2,455,245
Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value Measurement [Member] | Fair Value, Measurements, Nonrecurring [Member] | Securities held-to-maturity [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held-to-maturity investment securities	4,209,121	4,456,350
Fair Value, Inputs, Level 3 [Member] | Estimate of Fair Value Measurement [Member] | Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans and leases, net	18,155,798	17,211,619
Fair Value, Inputs, Level 3 [Member] | Estimate of Fair Value Measurement [Member] | Fair Value, Measurements, Nonrecurring [Member] | Residential Mortgage [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage servicing assets	$ 45,478	$ 45,309

Retirement Benefit Plans (Narra

Retirement Benefit Plans (Narrative) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Jul. 01, 2015
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Accumulated Benefit Obligation	$ 214,000	$ 245,500
Net actuarial loss	$ 5,700
Assumed healthcare cost trend (as a percent)	7.00%
Healthcare-cost trend rate in 2024 (as a percent)	4.60%
Employer matching contribution, percent of match	100.00%
Employer matching contribution, percent of employees' gross pay	2.00%
Employer matching contribution, additional percent of match	50.00%
Employer additional matching contribution, percent of employees' gross pay	6.00%
Compensation expense	$ 12,400	12,000	$ 11,100
Multiemployer Plans, Pension [Member]
Defined Benefit Plan Disclosure [Line Items]
Funded status of plan				$ (2,000)
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Employer contributions	$ 0	$ 0
Expected long-term return on assets (as a percent)	6.00%	6.50%	7.00%
Funded status of plan	$ (17,541)	$ (13,093)
SERP [Member]
Defined Benefit Plan Disclosure [Line Items]
Employer contributions	11,364	122
Funded status of plan	(1,835)	(13,096)
Other Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Employer contributions	$ 208	$ 219
Assumed healthcare cost trend (as a percent)	7.00%	7.50%	8.25%
Increase in net periodic postretirement benefit cost if trend increased by 1%	$ 4
Increase in accumulated benefit obligation if trend increased by 1%	111
Decrease in net periodic postretirement benefit cost if trend rate decreased by 1%	3
Decrease in accumulated benefit obligation if trend rate decreased 1%	102
Funded status of plan	$ (2,612)	$ (3,094)
Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Employer matching contribution, percent of employees' gross pay	3.00%

Retirement Benefit Plans (Chang

Retirement Benefit Plans (Changes in Plan Assets and Funded Status of Pension Plans and Other Postretirement Benefit Plans) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Change in plan assets:
Beginning balance	$ 216,225
Ending balance	191,972	$ 216,225
Pension Plan [Member]
Change in benefit obligation:
Beginning balance	229,318	211,508
Service cost	0	50	$ 45
Interest cost	7,212	7,314	8,441
Actuarial loss (gain)	(18,499)	18,396
Benefits paid and administrative expenses	(8,518)	(7,950)
Ending balance (1)	209,513	229,318	211,508
Change in plan assets:
Beginning balance	216,225	192,922
Actual return on plan assets	(15,735)	31,253
Employer contributions	0	0
Benefits paid and administrative expenses	(8,518)	(7,950)
Ending balance	191,972	216,225	192,922
Funded status of the plan at year end (2)	(17,541)	(13,093)
SERP [Member]
Change in benefit obligation:
Beginning balance	13,096	11,806
Service cost	0	0	0
Interest cost	103	375	389
Actuarial loss (gain)	0	1,037
Benefits paid and administrative expenses	(11,364)	(122)
Ending balance (1)	1,835	13,096	11,806
Change in plan assets:
Beginning balance	0	0
Actual return on plan assets	0	0
Employer contributions	11,364	122
Benefits paid and administrative expenses	(11,364)	(122)
Ending balance	0	0	0
Funded status of the plan at year end (2)	(1,835)	(13,096)
Other Benefits [Member]
Change in benefit obligation:
Beginning balance	3,094	3,852
Service cost	0	0	0
Interest cost	78	92	125
Actuarial loss (gain)	(352)	(631)
Benefits paid and administrative expenses	(208)	(219)
Ending balance (1)	2,612	3,094	3,852
Change in plan assets:
Beginning balance	0	0
Actual return on plan assets	0	0
Employer contributions	208	219
Benefits paid and administrative expenses	(208)	(219)
Ending balance	0	0	$ 0
Funded status of the plan at year end (2)	$ (2,612)	$ (3,094)

Retirement Benefit Plans (Summa

Retirement Benefit Plans (Summary of Components of Accumulated Other Comprehensive Loss Related to Pensions and Postretirement Benefits) (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Defined Benefit Plan Disclosure [Line Items]
Deferred tax benefit		$ 495	$ (2,632)	$ (2,502)
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Net actuarial loss (gain)	$ 59,433	64,523	59,433
Prior service cost	0	0	0
Total pre-tax amounts included in AOCL	59,433	64,523	59,433
Deferred tax benefit	13,407	14,623
Amounts included in accumulated AOCL, net of tax	46,026	49,900	46,026
SERP [Member]
Defined Benefit Plan Disclosure [Line Items]
Net actuarial loss (gain)	3,299	453	3,299
Prior service cost	0	0	0
Total pre-tax amounts included in AOCL	3,299	453	3,299
Deferred tax benefit	744	103
Amounts included in accumulated AOCL, net of tax	2,555	350	2,555
Other Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Net actuarial loss (gain)	(16)	(368)	(16)
Prior service cost	0	0	0
Total pre-tax amounts included in AOCL	(16)	(368)	(16)
Deferred tax benefit	(3)	(83)
Amounts included in accumulated AOCL, net of tax	$ (13)	$ (285)	$ (13)

Retirement Benefit Plans (Expec

Retirement Benefit Plans (Expected Future Benefit Payments) (Details) $ in Thousands	Dec. 31, 2018USD ($)
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
2,018	$ 8,636
2,019	9,011
2,020	9,740
2,021	10,416
2,022	10,468
2024-2028	57,158
SERP [Member]
Defined Benefit Plan Disclosure [Line Items]
2,018	130
2,019	133
2,020	133
2,021	133
2,022	131
2024-2028	650
Other Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
2,018	331
2,019	318
2,020	301
2,021	283
2,022	262
2024-2028	$ 978

Retirement Benefit Plans (Sum_2

Retirement Benefit Plans (Summary of Net Periodic Benefit Costs) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 0	$ 50	$ 45
Interest cost on benefit obligations	7,212	7,314	8,441
Expected return on plan assets	(12,716)	(12,296)	(11,461)
Amortization of prior service cost	0	0	0
Recognized net loss	4,862	5,864	6,665
Net periodic benefit cost (benefit)	(642)	932	3,690
SERP [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	0	0	0
Interest cost on benefit obligations	103	375	389
Expected return on plan assets	0	0	0
Amortization of prior service cost	0	0	0
Recognized net loss	2,846	748	426
Net periodic benefit cost (benefit)	2,949	1,123	815
Other Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	0	0	0
Interest cost on benefit obligations	78	92	125
Expected return on plan assets	0	0	0
Amortization of prior service cost	0	0	14
Recognized net loss	0	0	35
Net periodic benefit cost (benefit)	$ 78	$ 92	$ 174

Retirement Benefit Plans (Cha_2

Retirement Benefit Plans (Changes in Other Comprehensive Income) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Accumulated Other Comprehensive Income (Loss) [Line Items]
Net (gain) loss	$ 9,600	$ (155)	$ 368
Amounts reclassified from AOCL	(7,708)	(6,612)	(7,126)
Total (gain) loss recognized in OCI	1,892	(6,767)	(6,772)
Pension Plan [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Net (gain) loss	9,952	(561)	(715)
Amounts reclassified from AOCL	(4,862)	(5,864)	(6,665)
Amortization of prior service cost	0	0	0
Total (gain) loss recognized in OCI	5,090	(6,425)	(7,380)
SERP [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Net (gain) loss	0	1,037	1,023
Amounts reclassified from AOCL	(2,846)	(748)	(426)
Amortization of prior service cost	0	0	0
Total (gain) loss recognized in OCI	(2,846)	289	597
Other Benefits [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Net (gain) loss	(352)	(631)	60
Amounts reclassified from AOCL	0	0	(35)
Amortization of prior service cost	0	0	(14)
Total (gain) loss recognized in OCI	$ (352)	$ (631)	$ 11

Retirement Benefit Plans (Sum_3

Retirement Benefit Plans (Summary of Fair Value of Plan Assets by Level) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 191,972	$ 216,225
Quoted Prices In Active Markets for Identical Assets (Level 1) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	32,336	38,963
Significant Other Observable Inputs (Level 2) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	177,262
Significant Unobservable Inputs (Level 3) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0	$ 793
Fair Value Measured at Net Asset Value Per Share [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	159,636	0
Exchange traded funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	30,641	37,848
Exchange traded funds [Member] | Quoted Prices In Active Markets for Identical Assets (Level 1) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	30,641	37,848
Exchange traded funds [Member] | Significant Other Observable Inputs (Level 2) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Exchange traded funds [Member] | Significant Unobservable Inputs (Level 3) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Exchange traded funds [Member] | Fair Value Measured at Net Asset Value Per Share [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Defined Benefit Plan, Cash and Cash Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1,695	1,115
Defined Benefit Plan, Cash and Cash Equivalents [Member] | Quoted Prices In Active Markets for Identical Assets (Level 1) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1,695	1,115
Defined Benefit Plan, Cash and Cash Equivalents [Member] | Significant Other Observable Inputs (Level 2) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Defined Benefit Plan, Cash and Cash Equivalents [Member] | Significant Unobservable Inputs (Level 3) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Defined Benefit Plan, Cash and Cash Equivalents [Member] | Fair Value Measured at Net Asset Value Per Share [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Fixed Income Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	107,753	107,430
Fixed Income Funds [Member] | Quoted Prices In Active Markets for Identical Assets (Level 1) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Fixed Income Funds [Member] | Significant Other Observable Inputs (Level 2) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	107,430
Fixed Income Funds [Member] | Significant Unobservable Inputs (Level 3) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Fixed Income Funds [Member] | Fair Value Measured at Net Asset Value Per Share [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	107,753	0
Equity Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	51,883	69,832
Equity Funds [Member] | Quoted Prices In Active Markets for Identical Assets (Level 1) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Equity Funds [Member] | Significant Other Observable Inputs (Level 2) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	69,832
Equity Funds [Member] | Significant Unobservable Inputs (Level 3) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Equity Funds [Member] | Fair Value Measured at Net Asset Value Per Share [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 51,883	$ 0

Retirement Benefit Plans (Cha_3

Retirement Benefit Plans (Changes in Fair Value of Level 3 Plan Assets) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]
Beginning balance	$ 216,225
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3		$ (705)
Ending balance	191,972	216,225
Significant Unobservable Inputs (Level 3) [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]
Beginning balance	0	793
Employer contributions		78
Unrealized gains relating to instruments still held at the reporting date		0
Benefit payments, administrative expenses		(166)
Ending balance	$ 0	$ 0

Retirement Benefit Plans (Defin

Retirement Benefit Plans (Defined Benefit, Information about Plan Assets) (Details)	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Defined Benefit Plan Disclosure [Line Items]
Target Allocation (as a percent)	100.00%
Percentage of Pension Plan assets	100.00%		100.00%
Fixed Income Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Target Allocation (as a percent)	55.00%
Percentage of Pension Plan assets	56.00%		50.00%
Equity Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Target Allocation (as a percent)	45.00%
Percentage of Pension Plan assets	43.00%		50.00%
Defined Benefit Plan, Cash and Cash Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Target Allocation (as a percent)	0.00%
Percentage of Pension Plan assets		1.00%	0.00%

Retirement Benefit Plans (Weigh

Retirement Benefit Plans (Weighted Average Assumptions used to Determine Benefit Obligations) (Details)	Dec. 31, 2018	Dec. 31, 2017
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate (as a percent)	4.12%	3.50%
SERP [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate (as a percent)	3.95%	3.30%
Other Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate (as a percent)	3.69%	3.00%

Retirement Benefit Plans (Wei_2

Retirement Benefit Plans (Weighted Average Assumptions used to Determine Net Periodic Benefit Cost) (Details)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Defined Benefit Plan Disclosure [Line Items]
Assumed healthcare cost trend (as a percent)	7.00%
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate (as a percent)	3.50%	4.01%	4.20%
Expected long-term return on assets (as a percent)	6.00%	6.50%	7.00%
SERP [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate (as a percent)	3.30%	3.63%	3.75%
Other Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate (as a percent)	3.00%	3.27%	3.35%
Assumed healthcare cost trend (as a percent)	7.00%	7.50%	8.25%

Retirement Benefit Plans (Contr

Retirement Benefit Plans (Contributions and Funding Status of the Fund) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Retirement Benefits [Abstract]
Contributions by Webster Bank	$ 679	$ 614	$ 690
Funded Status of the Plan at December 31,	At least 80 percent	At least 80 percent

Share-Based Plans (Narrative) (

Share-Based Plans (Narrative) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares authorized	13,400,000
Number of common shares available for grant	2,200,000
Vesting period (in years)	1 year
Stock options granted	182,553
Aggregate intrinsic value	$ 13.3
Total intrinsic value of options exercised	$ 9.7	$ 11.1	$ 6.4
Stock Appreciation Rights (SARs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock appreciation rights granted	0
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock appreciation rights granted	151,833
Unrecognized stock compensation expense	$ 14
Unrecognized stock compensation expense, recognition period (in years)	1 year 10 months 24 days
Fair value of restricted stock awards	$ 11.1	$ 12.7	$ 11.6
Restricted Stock [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of common shares available for grant	100,000
Time Based Restricted Stock Awards [Member] | Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period (in years)	1 year
Time Based Restricted Stock Awards [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period (in years)	3 years
Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock appreciation rights granted	75,707
Vesting period (in years)	3 years
Award vesting percentage	50.00%
Performance Shares [Member] | Minimum [Member] | Share-based Compensation Award, Tranche One [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting percentage	0.00%
Performance Shares [Member] | Maximum [Member] | Share-based Compensation Award, Tranche One [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting percentage	150.00%
Employee Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options granted	0
Number of options outstanding (in shares)	480,792	673,039
Employee Stock Option [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Contractual life (in years)	P10Y
Non-Qualified Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of options outstanding (in shares)	446,904
Incentive Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of options outstanding (in shares)	33,888

Share-Based Plans (Summary of S

Share-Based Plans (Summary of Stock-based Compensation Expense Recognized) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation	$ 11,612	$ 12,276	$ 11,438
Income tax benefit	8,545	11,849	4,132
Employee Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation	$ 0	$ 0	43
Restricted stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation			$ 11,395

Share-Based Plans (Summary of R

Share-Based Plans (Summary of Restricted Stock and Stock Option Activity) (Detail)	12 Months Ended
	Dec. 31, 2018$ / sharesshares
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Options granted, Number of Shares	182,553
Options exercised, Number of Shares	182,517
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Restricted stock, Outstanding at beginning of period (in shares)	207,800
Restricted Stock, Granted (in shares)	151,833
Restricted stock, Vested restricted stock awards (in shares)	171,269
Restricted stock, Forfeited (in shares)	10,923
Restricted stock, Outstanding at end of period (in shares)	177,441
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Restricted stock, at beginning of period, Weighted-average Grant Date Fair Value (in dollars per share) | $ / shares	$ 43.16
Restricted stock, Granted (in dollars per share) | $ / shares	58.34
Restricted stock, Vested restricted stock awards (in dollars per share) | $ / shares	45.54
Restricted stock, Forfeited (in dollars per share) | $ / shares	52.94
Restricted stock, at end of period, Weighted-average Grant Date Fair Value (in dollars per share) | $ / shares	$ 53.05
Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Restricted stock, Outstanding at beginning of period (in shares)	78,916
Restricted Stock, Granted (in shares)	75,707
Restricted stock, Vested restricted stock awards (in shares)	71,357
Restricted stock, Forfeited (in shares)	13,847
Restricted stock, Outstanding at end of period (in shares)	69,419
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Restricted stock, at beginning of period, Weighted-average Grant Date Fair Value (in dollars per share) | $ / shares	$ 45.35
Restricted stock, Granted (in dollars per share) | $ / shares	55.82
Restricted stock, Vested restricted stock awards (in dollars per share) | $ / shares	46.50
Restricted stock, Forfeited (in dollars per share) | $ / shares	51.19
Restricted stock, at end of period, Weighted-average Grant Date Fair Value (in dollars per share) | $ / shares	$ 54.43
Employee Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Options outstanding, at beginning of period, Number of Shares	673,039
Options granted, Number of Shares	0
Options exercised, Number of Shares	192,247
Options forfeited, Number of Shares	0
Options outstanding, at end of period, Number of Shares	480,792
Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Options, at beginning of period, Weighted-average Exercise Price (in dollars per share) | $ / shares	$ 18.75
Options granted, Weighted-Average Exercise Price (in dollars per share) | $ / shares	0
Options exercised, Weighted-Average Exercise Price (in dollars per share) | $ / shares	11.30
Options forfeited, Weighted-Average Exercise Price (in dollars per share) | $ / shares	0
Options, at end of period, Weighted-average Exercise Price (in dollars per share) | $ / shares	$ 21.73

Share-Based Plans (Options Outs

Share-Based Plans (Options Outstanding and Options Exercisable) (Details)	12 Months Ended
	Dec. 31, 2018$ / sharesshares
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options Outstanding, Number of Shares | shares	480,792
Options Outstanding, Weighted-Average Remaining Contractual Life (years)	3 years 4 months 24 days
Options Outstanding, Weighted-Average Exercise Price (in dollars per share)	$ 21.73
Options Exercisable, Number of Shares | shares	480,792
Options Exercisable, Weighted-Average Remaining Contractual Life (years)	3 years 4 months 15 days
Options Exercisable, Weighted-Average Remaining Contractual Life (years)	$ 21.73
$5.14 - 12.85 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of exercise prices, Minimum (in dollars per share)	5.14
Range of exercise prices, Maximum (in dollars per share)	$ 12.85
Options Outstanding, Number of Shares | shares	48,568
Options Outstanding, Weighted-Average Remaining Contractual Life (years)	6 months
Options Outstanding, Weighted-Average Exercise Price (in dollars per share)	$ 7.42
Options Exercisable, Number of Shares | shares	48,568
Options Exercisable, Weighted-Average Remaining Contractual Life (years)	5 months 15 days
Options Exercisable, Weighted-Average Remaining Contractual Life (years)	$ 7.42
22.04 - 25.15 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of exercise prices, Minimum (in dollars per share)	22.04
Range of exercise prices, Maximum (in dollars per share)	$ 25.15
Options Outstanding, Number of Shares | shares	432,224
Options Outstanding, Weighted-Average Remaining Contractual Life (years)	3 years 8 months 12 days
Options Outstanding, Weighted-Average Exercise Price (in dollars per share)	$ 23.34
Options Exercisable, Number of Shares | shares	432,224
Options Exercisable, Weighted-Average Remaining Contractual Life (years)	3 years 8 months 15 days
Options Exercisable, Weighted-Average Remaining Contractual Life (years)	$ 23.34

Segment Reporting Segment Repor

Segment Reporting Segment Reporting Narrative (Details)	12 Months Ended
	Dec. 31, 2018Segment
Segment Reporting Information [Line Items]
Number of Reportable Segments	3

Segment Reporting - Operating R

Segment Reporting - Operating Results and Total Assets Reportable Segments (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Segment Reporting Information [Line Items]
Net interest income	$ 237,131	$ 230,372	$ 225,010	$ 214,168	$ 204,932	$ 200,904	$ 197,787	$ 192,664	$ 906,681	$ 796,287	$ 718,513
Provision for loan and lease losses	10,000	10,500	10,500	11,000	13,000	10,150	7,250	10,500	42,000	40,900	56,350
Net interest income (loss) after provision for loan and lease losses									864,681	755,387	662,163
Non-interest income									282,568	259,478	264,478
Non-interest expense	174,759	178,783	180,459	171,615	171,049	161,823	164,419	163,784	705,616	661,075	623,191
Income before income tax expense	125,535	113,373	102,425	100,300	86,922	94,777	90,669	81,422	441,633	353,790	303,450
Income tax expense (benefit)	26,697	13,700	20,743	20,075	17,029	30,281	29,090	21,951	81,215	98,351	96,323
Net income	98,838	$ 99,673	$ 81,682	$ 80,225	69,893	$ 64,496	$ 61,579	$ 59,471	360,418	255,439	207,127
Total Assets	27,610,315				26,487,645				27,610,315	26,487,645
Operating Segments [Member] | Commercial Banking [Member]
Segment Reporting Information [Line Items]
Net interest income									356,509	322,393	287,596
Provision for loan and lease losses									34,773	38,518	37,455
Net interest income (loss) after provision for loan and lease losses									321,736	283,875	250,141
Non-interest income									64,765	55,194	57,253
Non-interest expense									174,054	154,037	138,379
Income before income tax expense									212,447	185,032	169,015
Income tax expense (benefit)									52,262	51,438	53,649
Net income									160,185	133,594	115,366
Total Assets	10,477,050				9,350,028				10,477,050	9,350,028
Operating Segments [Member] | Community Banking [Member]
Segment Reporting Information [Line Items]
Net interest income									404,869	383,700	367,137
Provision for loan and lease losses									7,227	2,382	18,895
Net interest income (loss) after provision for loan and lease losses									397,642	381,318	348,242
Non-interest income									109,669	107,368	110,197
Non-interest expense									384,599	373,081	369,132
Income before income tax expense									122,712	115,605	89,307
Income tax expense (benefit)									24,420	32,137	28,348
Net income									98,292	83,468	60,959
Total Assets	8,727,335				8,909,671				8,727,335	8,909,671
Operating Segments [Member] | HSA Bank [Member]
Segment Reporting Information [Line Items]
Net interest income									143,255	104,704	81,451
Provision for loan and lease losses									0	0	0
Net interest income (loss) after provision for loan and lease losses									143,255	104,704	81,451
Non-interest income									89,323	77,378	71,710
Non-interest expense									124,594	113,143	97,152
Income before income tax expense									107,984	68,939	56,009
Income tax expense (benefit)									28,076	19,165	17,779
Net income									79,908	49,774	38,230
Total Assets	70,826				76,308				70,826	76,308
Corporate, Non-Segment [Member]
Segment Reporting Information [Line Items]
Net interest income									2,048	(14,510)	(17,671)
Provision for loan and lease losses									0	0	0
Net interest income (loss) after provision for loan and lease losses									2,048	(14,510)	(17,671)
Non-interest income									18,811	19,538	25,318
Non-interest expense									22,369	20,814	18,528
Income before income tax expense									(1,510)	(15,786)	(10,881)
Income tax expense (benefit)									(23,543)	(4,389)	(3,453)
Net income									22,033	(11,397)	$ (7,428)
Total Assets	$ 8,335,104				$ 8,151,638				$ 8,335,104	$ 8,151,638

Revenue from contracts with C_3

Revenue from contracts with Customers Revenue from Contracts with Customers (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Revenue from Contract with Customer, Excluding Assessed Tax	$ 200,673	$ 185,945	$ 173,377
Noninterest Income	282,568	259,478	264,478
Deposit Service Fees [Member]
Revenue from Contract with Customer, Excluding Assessed Tax	162,183	151,137	140,685
Investment Advisory, Management and Administrative Service [Member]
Revenue from Contract with Customer, Excluding Assessed Tax	32,843	31,055	28,962
Other Non Interest Income [Member]
Revenue from Contract with Customer, Excluding Assessed Tax	5,647	3,753	3,730
Non-Interest Income Within the Scope of Other GAAP Topics [Member]
Noninterest Income	81,895	73,533	91,101
Operating Segments [Member] | Commercial Banking [Member]
Revenue from Contract with Customer, Excluding Assessed Tax	22,920	22,020	20,293
Noninterest Income	64,765	55,194	57,253
Operating Segments [Member] | Commercial Banking [Member] | Deposit Service Fees [Member]
Revenue from Contract with Customer, Excluding Assessed Tax	12,775	12,203	11,143
Operating Segments [Member] | Commercial Banking [Member] | Investment Advisory, Management and Administrative Service [Member]
Revenue from Contract with Customer, Excluding Assessed Tax	10,145	9,817	9,150
Operating Segments [Member] | Commercial Banking [Member] | Other Non Interest Income [Member]
Revenue from Contract with Customer, Excluding Assessed Tax	0	0	0
Operating Segments [Member] | Commercial Banking [Member] | Non-Interest Income Within the Scope of Other GAAP Topics [Member]
Noninterest Income	41,845	33,174	36,960
Operating Segments [Member] | Community Banking [Member]
Revenue from Contract with Customer, Excluding Assessed Tax	88,387	86,291	83,857
Noninterest Income	109,669	107,368	110,197
Operating Segments [Member] | Community Banking [Member] | Deposit Service Fees [Member]
Revenue from Contract with Customer, Excluding Assessed Tax	63,522	64,194	63,143
Operating Segments [Member] | Community Banking [Member] | Investment Advisory, Management and Administrative Service [Member]
Revenue from Contract with Customer, Excluding Assessed Tax	22,732	21,274	19,842
Operating Segments [Member] | Community Banking [Member] | Other Non Interest Income [Member]
Revenue from Contract with Customer, Excluding Assessed Tax	2,133	823	872
Operating Segments [Member] | Community Banking [Member] | Non-Interest Income Within the Scope of Other GAAP Topics [Member]
Noninterest Income	21,282	21,077	26,340
Operating Segments [Member] | HSA Bank [Member]
Revenue from Contract with Customer, Excluding Assessed Tax	89,323	77,378	69,020
Noninterest Income	89,323	77,378	71,710
Operating Segments [Member] | HSA Bank [Member] | Deposit Service Fees [Member]
Revenue from Contract with Customer, Excluding Assessed Tax	85,809	74,448	66,162
Operating Segments [Member] | HSA Bank [Member] | Investment Advisory, Management and Administrative Service [Member]
Revenue from Contract with Customer, Excluding Assessed Tax	0	0	0
Operating Segments [Member] | HSA Bank [Member] | Other Non Interest Income [Member]
Revenue from Contract with Customer, Excluding Assessed Tax	3,514	2,930	2,858
Operating Segments [Member] | HSA Bank [Member] | Non-Interest Income Within the Scope of Other GAAP Topics [Member]
Noninterest Income	0	0	2,690
Corporate, Non-Segment [Member]
Revenue from Contract with Customer, Excluding Assessed Tax	43	256	207
Noninterest Income	18,811	19,538	25,318
Corporate, Non-Segment [Member] | Deposit Service Fees [Member]
Revenue from Contract with Customer, Excluding Assessed Tax	77	292	237
Corporate, Non-Segment [Member] | Investment Advisory, Management and Administrative Service [Member]
Revenue from Contract with Customer, Excluding Assessed Tax	(34)	(36)	(30)
Corporate, Non-Segment [Member] | Other Non Interest Income [Member]
Revenue from Contract with Customer, Excluding Assessed Tax	0	0	0
Corporate, Non-Segment [Member] | Non-Interest Income Within the Scope of Other GAAP Topics [Member]
Noninterest Income	$ 18,768	$ 19,282	$ 25,111

Commitments and Contingencies_2

Commitments and Contingencies (Narrative) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Commitments and Contingencies Disclosure [Abstract]
Rental expense under leases	$ 31	$ 31.1	$ 30.4
Rental income	$ 0.7	$ 0.7	$ 0.8

Commitments and Contingencies_3

Commitments and Contingencies (Schedule of Future Minimum Rental Payments and Receipts for Leases) (Details) $ in Thousands	Dec. 31, 2018USD ($)
Commitments and Contingencies Disclosure [Abstract]
Rental Payments, 2019	$ 30,889
Rental Payments, 2020	30,049
Rental Payments, 2021	28,274
Rental Payments, 2022	24,498
Rental Payments, 2023	21,231
Rental Payments, Thereafter	78,882
Rental Payments, Total	213,823
Rental Receipts, 2019	805
Rental Receipts, 2020	667
Rental Receipts, 2021	547
Rental Receipts, 2022	493
Rental Receipts, 2023	427
Rental Receipts, Thereafter	1,403
Rental Receipts, Total	$ 4,342

Commitments and Contingencies_4

Commitments and Contingencies (Outstanding Financial Instruments Contract Amounts Represent Credit Risk) (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Loss Contingencies [Line Items]
Total credit-related financial instruments with off-balance sheet risk	$ 6,050,806	$ 5,806,789
Standby letters of credit [Member]
Loss Contingencies [Line Items]
Total credit-related financial instruments with off-balance sheet risk	189,040	195,902
Letter of Credit [Member]
Loss Contingencies [Line Items]
Total credit-related financial instruments with off-balance sheet risk	21,181	43,200
Commitments to extend credit [Member]
Loss Contingencies [Line Items]
Total credit-related financial instruments with off-balance sheet risk	$ 5,840,585	$ 5,567,687

Commitments and Contingencies_5

Commitments and Contingencies (Schedule for Unfunded Commitments) (Details) - SEC Schedule, 12-09, Allowance, Credit Loss [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Beginning balance	$ 2,362	$ 2,287	$ 2,119
Provision	144	75	168
Ending balance	$ 2,506	$ 2,362	$ 2,287

Parent Company Information (Com

Parent Company Information (Components of Condensed Balance Sheets The Parent Company) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Assets:
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	$ 260,422	$ 231,158	$ 190,663	$ 199,693
Other assets	313,256	286,677
Total assets	27,610,315	26,487,645
Liabilities and shareholders’ equity:
Total liabilities	24,723,800	23,785,687
Total liabilities and shareholders' equity	27,610,315	26,487,645
Parent Company [Member]
Assets:
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	317,473	181,085	$ 152,947	$ 279,644
Intercompany debt securities	150,000	150,000
Investment in subsidiaries	2,633,848	2,585,955
Due to Affiliate	(36)	0
Alternative investments	3,252	2,939
Other assets	12,003	13,252
Total assets	3,116,612	2,933,231
Liabilities and shareholders’ equity:
Senior notes	148,701	148,447
Junior subordinated debt	77,320	77,320
Accrued interest payable	2,664	2,616
Due to subsidiaries	0	575
Other liabilities	1,412	2,315
Total liabilities	230,097	231,273
Shareholders’ equity	2,886,515	2,701,958
Total liabilities and shareholders' equity	$ 3,116,612	$ 2,933,231

Parent Company Information (C_2

Parent Company Information (Components of Condensed Income Statement The Parent Company) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Operating Income:
Loss on sale of investment securities									$ 0	$ 0	$ 414
Other non-interest income	$ 73,163	$ 72,284	$ 68,374	$ 68,747	$ 66,039	$ 65,846	$ 64,551	$ 63,042
Operating Expense:
Compensation and benefits									381,496	356,505	325,998
Non-interest expense									91,046	90,626	90,039
Income tax benefit	$ (26,697)	$ (13,700)	$ (20,743)	$ (20,075)	$ (17,029)	$ (30,281)	$ (29,090)	$ (21,951)	(81,215)	(98,351)	(96,323)
Parent Company [Member]
Operating Income:
Dividend income from bank subsidiary									290,000	120,000	145,000
Interest on securities and deposits									7,342	4,477	1,911
Loss on sale of investment securities									0	0	(2,410)
Alternative investments income									290	1,504	176
Other non-interest income									805	204	7,485
Total operating income									298,437	126,185	152,162
Operating Expense:
Interest expense on borrowings									11,127	10,380	9,981
Non-interest expense									19,105	23,008	17,739
Total operating expense									30,232	33,388	27,720
Income before income tax benefit and equity in undistributed earnings of subsidiaries									268,205	92,797	124,442
Income tax benefit									2,207	3,004	3,086
Equity in undistributed earnings of subsidiaries									90,006	159,638	79,599
Net income									$ 360,418	$ 255,439	$ 207,127

Parent Company Information (C_3

Parent Company Information (Components of Condensed Comprehensive Income) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Other comprehensive income (loss), net of tax:
Net unrealized gains on available for sale securities	$ (43,427)	$ (7,590)	$ (9,069)
Net unrealized gains on derivative instruments	208	181	825
Other comprehensive loss of subsidiaries and associated companies	321,297	256,549	208,240
Other comprehensive (loss) income, net of tax	(39,121)	1,110	1,113
Parent Company [Member]
Condensed Statement of Income Captions [Line Items]
Net income	360,418	255,439	207,127
Other comprehensive income (loss), net of tax:
Net unrealized gains on available for sale securities	0	0	584
Net unrealized gains on derivative instruments	1,447	1,216	1,223
Other comprehensive loss of subsidiaries and associated companies	(40,568)	(106)	(694)
Other comprehensive (loss) income, net of tax	(39,121)	1,110	1,113
Comprehensive income	$ 321,297	$ 256,549	$ 208,240

Parent Company Information (C_4

Parent Company Information (Components of Condensed Cash Flow The Parent Company) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Adjustments to reconcile net income to net cash provided by operating activities:
Stock-based compensation	$ 11,612	$ 12,276	$ 11,438
Gain on redemption of other assets	0	0	(7,331)
Net cash provided by operating activities	469,408	444,966	398,145
Investing activities:
Purchases of intercompany debt securities	(1,215)	873	(381)
Net cash provided by (used for) investing activities	(1,361,373)	(527,220)	(1,635,006)
Financing activities:
Proceeds from Issuance of Redeemable Preferred Stock	0	145,056	0
Payments for Repurchase of Redeemable Preferred Stock	0	(122,710)	0
Cash dividends paid to common shareholders	(114,959)	(94,630)	(89,522)
Cash dividends paid to preferred shareholders	(7,875)	(8,096)	(8,096)
Exercise of stock options	2,173	8,259	11,762
Excess tax benefits from stock-based compensation	0	0	3,204
Common stock repurchased and acquired from stock compensation plan activity	(12,158)	(11,585)	(11,206)
Common stock warrants repurchased	0	0	(163)
Net cash (used for) provided by financing activities	921,229	122,749	1,227,831
Net decrease in cash and due from banks	29,264	40,495	(9,030)
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Beginning Balance	231,158	190,663	199,693
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Ending Balance	260,422	231,158	190,663
Parent Company [Member]
Operating activities:
Net income	360,418	255,439	207,127
Adjustments to reconcile net income to net cash provided by operating activities:
Equity in undistributed earnings of subsidiaries	(90,006)	(159,638)	(79,599)
Net cash provided by operating activities	282,986	115,957	127,899
Investing activities:
Proceeds from sales of available-for-sale securities	0	0	1,089
Purchases of intercompany debt securities	0	0	(150,000)
Proceeds from Sale of Other Assets, Investing Activities	0	7,581	0
Net cash provided by (used for) investing activities	0	7,581	(148,911)
Financing activities:
Proceeds from Issuance of Redeemable Preferred Stock	0	145,056	0
Payments for Repurchase of Redeemable Preferred Stock	0	(122,710)	0
Cash dividends paid to common shareholders	(114,959)	(94,630)	(89,522)
Cash dividends paid to preferred shareholders	(7,875)	(8,096)	(8,096)
Exercise of stock options	2,173	8,259	11,762
Excess tax benefits from stock-based compensation	0	0	3,204
Common stock repurchased and acquired from stock compensation plan activity	(25,937)	(23,279)	(22,870)
Common stock warrants repurchased	0	0	(163)
Net cash (used for) provided by financing activities	(146,598)	(95,400)	(105,685)
Net decrease in cash and due from banks	136,388	28,138	(126,697)
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Beginning Balance	181,085	152,947	279,644
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Ending Balance	$ 317,473	$ 181,085	$ 152,947

Selected Quarterly Consolidat_3

Selected Quarterly Consolidated Financial Information (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Selected Quarterly Financial Information [Abstract]
Interest income	$ 280,392	$ 268,363	$ 260,491	$ 245,921	$ 236,115	$ 231,021	$ 226,789	$ 219,680	$ 1,055,167	$ 913,605	$ 821,913
Interest expense	43,261	37,991	35,481	31,753	31,183	30,117	29,002	27,016	148,486	117,318	103,400
Net interest income	237,131	230,372	225,010	214,168	204,932	200,904	197,787	192,664	906,681	796,287	718,513
Provision for loan and lease losses	10,000	10,500	10,500	11,000	13,000	10,150	7,250	10,500	42,000	40,900	56,350
Non-interest income	73,163	72,284	68,374	68,747	66,039	65,846	64,551	63,042
Non-interest expense	174,759	178,783	180,459	171,615	171,049	161,823	164,419	163,784	705,616	661,075	623,191
Income before income tax expense	125,535	113,373	102,425	100,300	86,922	94,777	90,669	81,422	441,633	353,790	303,450
Income tax expense	26,697	13,700	20,743	20,075	17,029	30,281	29,090	21,951	81,215	98,351	96,323
Net income	98,838	99,673	81,682	80,225	69,893	64,496	61,579	59,471	360,418	255,439	207,127
Earnings applicable to common shareholders	$ 96,666	$ 97,460	$ 79,489	$ 78,083	$ 67,710	$ 62,426	$ 59,485	$ 57,342	$ 352,565	$ 247,255	$ 199,031
Earnings per common share:
Earnings per common share, Basic (in dollars per share)	$ 1.05	$ 1.06	$ 0.87	$ 0.85	$ 0.74	$ 0.68	$ 0.65	$ 0.62	$ 3.83	$ 2.68	$ 2.17
Earnings per common share, Diluted (in dollars per share)	$ 1.05	$ 1.06	$ 0.86	$ 0.85	$ 0.73	$ 0.67	$ 0.64	$ 0.62	$ 3.81	$ 2.67	$ 2.16