Webster Financial (WBS) 10-Q 6 Nov 17 2017 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2017	Oct. 31, 2017
Document and Entity Information [Abstract]
Document Period End Date	Sep. 30, 2017
Document Type	10-Q
Amendment Flag	false
Entity Registrant Name	WEBSTER FINANCIAL CORPORATION
Entity Common Stock, Shares Outstanding		92,074,790
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	Q3
Trading Symbol	WBS
Entity Central Index Key	801,337
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Assets:
Cash and due from banks	$ 215,244	$ 190,663
Interest-bearing deposits	26,992	29,461
Investment securities available-for-sale, at fair value	2,591,162	2,991,091
Investment securities held-to-maturity (fair value of $4,481,675 and $4,125,125)	4,497,311	4,160,658
Federal Home Loan Bank and Federal Reserve Bank stock	136,340	194,646
Loans held for sale (valued under fair value option $32,855 and $60,260)	32,855	67,577
Loans and leases	17,446,421	17,026,588
Allowance for loan and lease losses	(201,803)	(194,320)
Loans and leases, net	17,244,618	16,832,268
Deferred tax assets, net	82,895	84,391
Premises and equipment, net	130,358	137,413
Goodwill	538,373	538,373
Other intangible assets, net	30,589	33,674
Cash surrender value of life insurance policies	528,136	517,852
Accrued interest receivable and other assets	295,309	294,462
Total assets	26,350,182	26,072,529
Liabilities and shareholders' equity:
Noninterest-bearing Deposit Liabilities	4,138,206	4,021,061
Interest-bearing Deposit Liabilities	16,717,029	15,282,796
Total deposits	20,855,235	19,303,857
Securities sold under agreements to repurchase and other borrowings	902,902	949,526
Federal Home Loan Bank advances	1,507,681	2,842,908
Long-term debt	225,704	225,514
Accrued expenses and other liabilities	219,873	223,712
Total liabilities	23,711,395	23,545,517
Shareholders’ equity:
Preferred stock, $.01 par value; Authorized - 3,000,000 shares: Series E issued and outstanding (5,060 shares)	122,710	122,710
Common stock, $.01 par value: Authorized - 200,000,000 shares: Issued (93,651,601 shares)	937	937
Paid-in capital	1,123,685	1,125,937
Retained earnings	1,535,585	1,425,320
Treasury stock, at cost (1,764,131 and 1,899,502 shares)	(75,032)	(70,899)
Accumulated other comprehensive loss, net of tax	(69,098)	(76,993)
Total shareholders' equity	2,638,787	2,527,012
Total liabilities and shareholders' equity	$ 26,350,182	$ 26,072,529

Condensed Consolidated Balance3

Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Securities held-to-maturity ,fair value	$ 4,481,675	$ 4,125,125
Originated loans held for sale	$ 32,855	$ 60,260
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized (in shares)	3,000,000	3,000,000
Preferred stock, shares issued (in shares)	5,060	5,060
Preferred stock, shares outstanding (in shares)	5,060	5,060
Common stock par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	200,000,000	200,000,000
Common stock, shares issued (in shares)	93,679,599	93,651,601
Treasury stock ,shares (in shares)	1,764,131	1,899,502

Condensed Consolidated Statemen

Condensed Consolidated Statements of Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Interest Income:
Interest and fees on loans and leases	$ 181,130	$ 157,071	$ 523,394	$ 459,050
Taxable interest and dividends on investments	43,819	43,384	136,167	136,734
Non-taxable interest on investment securities	5,765	4,820	17,103	13,691
Loans held for sale	307	440	826	1,006
Total interest income	231,021	205,715	677,490	610,481
Interest Expense:
Deposits	16,760	12,594	44,874	37,267
Securities sold under agreements to repurchase and other borrowings	3,847	3,447	10,970	10,999
Federal Home Loan Bank advances	6,894	6,979	22,543	21,517
Long-term debt	2,616	2,498	7,748	7,444
Total interest expense	30,117	25,518	86,135	77,227
Net interest income	200,904	180,197	591,355	533,254
Provision for loan and lease losses	10,150	14,250	27,900	43,850
Net interest income after provision for loan and lease losses	190,754	165,947	563,455	489,404
Non-interest Income:
Deposit service fees	38,321	35,734	113,519	105,553
Loan and lease related fees	6,346	9,253	19,898	20,563
Wealth and investment services	7,750	7,593	22,900	21,992
Mortgage banking activities	2,421	4,322	8,038	11,335
Increase in cash surrender value of life insurance policies	3,720	3,743	10,943	11,060
Gain on sale of investment securities, net	0	0	0	414
Impairment loss on investment securities recognized in earnings	0	0	(126)	(149)
Other income	7,288	5,767	18,267	23,093
Total non-interest income	65,846	66,412	193,439	193,861
Non-interest Expense:
Compensation and benefits	89,192	83,148	264,822	244,089
Occupancy	14,744	15,004	46,957	44,915
Technology and equipment	22,580	19,753	66,646	59,067
Intangible assets amortization	1,002	1,493	3,085	4,570
Marketing	4,045	4,622	14,101	14,215
Professional and outside services	4,030	4,795	11,813	11,360
Deposit insurance	6,344	6,177	19,701	19,596
Other expense	19,886	21,105	62,901	63,508
Total non-interest expense	161,823	156,097	490,026	461,320
Income (loss) before income tax expense	94,777	76,262	266,868	221,945
Income tax expense	30,281	24,445	81,322	72,478
Net income	64,496	51,817	185,546	149,467
Preferred stock dividends and other	(2,070)	(2,183)	(6,284)	(6,540)
Earnings applicable to common shareholders	$ 62,426	$ 49,634	$ 179,262	$ 142,927
Earnings per common share:
Basic (in dollars per share)	$ 0.68	$ 0.54	$ 1.95	$ 1.57
Diluted (in dollars per share)	$ 0.67	$ 0.54	$ 1.94	$ 1.56

Condensed Consolidated Stateme5

Condensed Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Statement of Comprehensive Income [Abstract]
Net income	$ 64,496	$ 51,817	$ 185,546	$ 149,467
Other comprehensive income, net of tax:
Total securities available-for-sale and transferred	872	1,218	1,847	19,988
Total derivative instruments	1,111	2,015	2,921	1,589
Total defined benefit pension and other postretirement benefit plans	1,001	1,125	3,127	3,376
Other comprehensive income, net of tax	2,984	4,358	7,895	24,953
Comprehensive income	$ 67,480	$ 56,175	$ 193,441	$ 174,420

Condensed Consolidated Stateme6

Condensed Consolidated Statements of Shareholders' Equity (Unaudited) - USD ($) $ in Thousands	Total	Series E Preferred Stock [Member]	Preferred Stock [Member]	Common Stock [Member]	Paid-In Capital [Member]	Retained Earnings [Member]	Retained Earnings [Member]Series E Preferred Stock [Member]	Treasury Stock, at cost [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	149,467					149,467
Other comprehensive income, net of tax	24,953								24,953
Dividends and dividend equivalents declared on common stock $0.25 and $0.23 per share during the 3 months ended March 31, 2017 and 2016, respectively	(66,979)				109	(67,088)
Dividends on Series E preferred stock $400.00 per share for the 3 months ended March 31, 2017 and 2016		$ (6,072)					$ (6,072)
Stock-based compensation, net of tax impact	10,689				2,413	245		8,031
Exercise of stock options	2,372				(1,307)			3,679
Common shares acquired related to stock compensation plan activity	(5,392)							(5,392)
Common stock repurchase program	(11,206)							(11,206)
Common stock warrants repurchased	(163)				(163)
Ending Balance at Sep. 30, 2016	2,511,629		122,710	937	1,125,377	1,392,500		(76,742)	(53,153)
Beginning Balance at Jun. 30, 2016									(57,511)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	51,817
Other comprehensive income, net of tax	4,358								4,358
Ending Balance at Sep. 30, 2016	2,511,629		122,710	937	1,125,377	1,392,500		(76,742)	(53,153)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Fair Value	4,125,125
Beginning 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	185,546					185,546
Other comprehensive income, net of tax	7,895								7,895
Dividends and dividend equivalents declared on common stock $0.25 and $0.23 per share during the 3 months ended March 31, 2017 and 2016, respectively	(70,972)				124	(71,096)
Dividends on Series E preferred stock $400.00 per share for the 3 months ended March 31, 2017 and 2016		$ (6,072)					$ (6,072)
Stock-based compensation, net of tax impact	10,957					1,887		9,070
Exercise of stock options	5,301				(2,376)			7,677
Common shares acquired related to stock compensation plan activity	(9,295)							(9,295)
Common stock repurchase program	(11,585)							(11,585)
Ending Balance at Sep. 30, 2017	2,638,787		122,710	937	1,123,685	1,535,585		(75,032)	(69,098)
Beginning Balance at Jun. 30, 2017									(72,082)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	64,496
Other comprehensive income, net of tax	2,984								2,984
Ending Balance at Sep. 30, 2017	2,638,787		$ 122,710	$ 937	$ 1,123,685	$ 1,535,585		$ (75,032)	$ (69,098)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Fair Value	$ 4,481,675

Condensed Consolidated Stateme7

Condensed Consolidated Statements of Shareholders' Equity (Unaudited) (Parenthetical) - $ / shares	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Dividends on common stock and dividend equivalents declared (in dollars per share)	$ 0.77	$ 0.73
Series E Preferred Stock [Member]
Dividends on preferred stock (in dollars per share)	$ 1,200	$ 1,200

Condensed Consolidated Stateme8

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Operating Activities:
Net income	$ 185,546	$ 149,467
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for loan and lease losses	27,900	43,850
Deferred tax (benefit) expense	(3,241)	14,425
Depreciation and amortization	28,060	27,342
Amortization of earning assets and funding, premiums/discounts, net	33,338	42,855
Stock-based compensation	9,050	8,558
Gain on sale, net of write-down, on foreclosed and repossessed assets	(551)	(744)
Write-down (gain on sale), net on premises and equipment	218	(713)
Impairment loss on investment securities recognized in earnings	126	149
Gain on the sale of investment securities, net	0	(414)
Increase in cash surrender value of life insurance policies	(10,943)	(11,060)
Mortgage banking activities	(8,038)	(11,335)
Proceeds from sale of loans held for sale	262,029	298,840
Origination of loans held for sale	(227,435)	(320,739)
Net decrease (increase) in derivative contract assets net of liabilities	11,235	(73,765)
Net (increase) decrease in accrued interest receivable and other assets	(19,405)	51,270
Net increase (decrease) in accrued expenses and other liabilities	12,386	(30,419)
Net cash provided by operating activities	300,275	187,567
Investing Activities:
Net decrease in interest-bearing deposits	2,469	133,969
Purchases of available for sale investment securities	(305,309)	(615,174)
Proceeds from maturities and principal payments of available for sale investment securities	695,595	430,099
Proceeds from sales of available for sale investment securities	0	259,283
Purchases of held-to-maturity investment securities	(887,240)	(640,218)
Proceeds from maturities and principal payments of held-to-maturity investment securities	525,499	517,513
Net proceeds of Federal Home Loan Bank stock	58,306	3,243
Alternative investments return of capital (capital call), net	107	(649)
Net increase in loans	(446,454)	(1,010,423)
Proceeds from loans not originated for sale	7,445	20,764
Proceeds from Life Insurance Policy	746	0
Proceeds from the sale of foreclosed and repossessed assets	5,651	6,900
Proceeds from the sale of premises and equipment	2,182	1,550
Additions to premises and equipment	(20,034)	(31,250)
Proceeds from redemption of other assets	7,581	0
Net cash used for investing activities	(353,456)	(924,393)
Financing Activities:
Net increase in deposits	1,551,987	1,248,710
Proceeds from Federal Home Loan Bank advances	9,245,000	14,150,000
Repayments of Federal Home Loan Bank advances	(10,580,218)	(14,226,147)
Net decrease in securities sold under agreements to repurchase and other borrowings	(46,624)	(350,695)
Dividends paid to common shareholders	(70,732)	(66,648)
Dividends paid to preferred shareholders	(6,072)	(6,072)
Exercise of stock options	5,301	2,372
Excess tax benefits from stock-based compensation	0	2,363
Common stock repurchase program	(11,585)	(11,206)
Common shares purchased related to stock compensation plan activity	(9,295)	(5,392)
Common stock warrants repurchased	0	(163)
Net cash (used for) provided by financing activities	77,762	737,122
Net decrease in cash and due from banks	24,581	296
Cash and due from banks at beginning of period	190,663	199,693
Cash and due from banks at end of period	215,244	199,989
Supplemental disclosure of cash flow information:
Interest paid	85,242	79,054
Income taxes paid	78,832	61,639
Noncash investing and financing activities:
Real Estate Owned, Transfer to Real Estate Owned	6,503	4,917
Transfer of loans from portfolio to loans-held-for-sale	$ 0	$ 20,547

Summary of Significant Accounti

Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation and Significant Accounting Policies [Text Block]	Summary of Significant Accounting Policies Nature of Operations Webster Financial Corporation is a bank holding company and financial holding company under the Bank Holding Company Act, incorporated under the laws of Delaware in 1986 and headquartered in Waterbury, Connecticut. At September 30, 2017 , 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. The accompanying unaudited Condensed Consolidated Financial Statements of the Company have been prepared in conformity with the instructions for Form 10-Q and Rule 10-01 of Regulation S-X. Accordingly, they do not include all the information and notes required by GAAP for complete financial statements and should be read in conjunction with the Company's Consolidated Financial Statements, and Notes thereto, for the year ended December 31, 2016 , included in the Company's Annual Report on Form 10-K filed with the SEC on March 1, 2017. 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. Operating results for the interim periods disclosed herein are not necessarily indicative of the results that may be expected for the full year or any future period. Certain prior period amounts have been reclassified to conform to the current year's presentation. These reclassifications had an immaterial effect on non-interest income, non-interest expense, net cash provided by operating activities, and net cash used for investing activities. Significant Accounting Policy Updates Centrally Cleared Derivatives Effective during the first quarter of 2016, the Company offset the variation margin pertaining to derivatives reported on a net basis, subject to a legally enforceable master netting arrangement, with the same counterparty against the net derivative position on the Company's balance sheets. The Chicago Mercantile Exchange has amended their rulebooks to legally characterize variation margin payments for over-the-counter derivatives that clear, as settlements rather than collateral, effective January 3, 2017. The Company has updated its significant accounting policies to classify variation margin deemed to be legal settlements as a single unit of account with the derivative, for accounting and presentation purposes. The policy update does not result in a change in the presentation of the Company's balance sheets as the Company previously offset the variation margin pertaining to derivatives reporting on a net basis, subject to a legally enforceable master netting arrangement, with the same counterparty against the net derivative position. Accounting Standards Adopted during 2017 Effective January 1, 2017, the following new accounting guidance was adopted by the Company: ASU No. 2016-09, Compensation - Stock Compensation (Topic 718) - Improvements to Employee Share Based Payment Accounting The Update impacted the accounting for employee share-based payment transactions, including the income tax consequences, and classification on the statement of cash flows. The Update requires the Company to recognize the income tax effects of awards in the income statement on a prospective basis when the awards vest or are settled, compared to within additional paid-in capital. As a result, applicable excess tax benefits and tax deficiencies are recorded as an income tax benefit or expense, respectively. The Company elected to present the classification on the statement of cash flows on a prospective basis to better align this presentation with the income tax effects. The impact of the Update will vary from period to period based on the Company's stock price and the quantity of shares that vest or are settled within a given period. The Update also requires the Company to elect the accounting for forfeitures of share-based payments by either (i) recognizing forfeitures of awards as they occur or (ii) estimating the number of awards expected to be forfeited and adjusting the estimate when it is likely to change, as is currently required. The Company elected to account for forfeitures of share-based payments by estimating the number of awards expected to be forfeited and adjusting the estimate when it is likely to change, which is in accordance with the Company's previous accounting practices. The adoption of this accounting standard did not have a material impact on the Company's financial statements. ASU No. 2016-06, Derivatives and Hedging (Topic 815) - Contingent Put and Call Options in Debt Instruments. The Update clarifies the requirements for assessing whether contingent call (put) options that can accelerate the payment of principal on debt instruments are clearly and closely related to their debt hosts. The Update requires the assessment of embedded call (put) options solely in accordance with the four-step decision sequence. The Update clarified that companies are not required to assess whether the event triggering the ability to exercise the call/put option was also clearly and closely related. The adoption of this accounting standard did not have a material impact on the Company's financial statements, as the Company has not performed the additional step of assessing whether the event triggering the ability to exercise the call (put) option was clearly and closely related, which was deemed not required by the Update. 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. 2017-12, Derivatives and Hedging (Topic 815) - Targeted Improvements to Accounting for Hedging Activities. The purpose of the Update is to better align a company’s 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 Company is in the process of assessing all potential impacts of the standard. The Update is effective for the first quarter of 2019, early adoption is permitted. The Company is evaluating the potential to early adopt the Update. ASU No. 2017-08, Receivables - Nonrefundable Fees and Other Costs (Subtopic 310-20) - Premium Amortization on Purchased Callable Debt Securities. The Update is intended to enhance the accounting for the amortization of premiums for purchased callable debt securities. Specifically, 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. The Update is being issued in response to concerns from stakeholders that, current GAAP excludes certain callable debt securities from consideration of early repayment of principal even if the holder is certain that the call will be exercised. The Update, upon adoption, is expected to accelerate the Company’s recognition of premium amortization on debt securities held within the portfolio. The amendments in the Update will be applied on a modified retrospective basis through a cumulative-effect adjustment directly through retained earnings upon adoption. Management is in the process of evaluating the full impact of adopting the Update including, but not limited to the following: • Modifying system amortization requirements; • Evaluation of premiums associated with debt securities to determine the appropriate cumulative-effect adjustment; and • Establishing new accounting policies pertaining to premium amortization on purchased callable debt securities. The Update is effective for the first quarter of 2019, early adoption is permitted. The Company is evaluating the potential to early adopt the Update. 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 disaggregate the current-service-cost component from the other components of net benefit cost (the “other components”) and present it with other current compensation costs for related employees in the income statement and present the other components elsewhere in the income statement and outside of income from operations if that subtotal is presented. In addition, the Update requires entities to disclose the income statement lines that contain the other components if they are not presented on appropriately described separate lines. The new guidance will be applied on a retrospective basis. The Company intends to adopt the Update for the first quarter of 2018. The Company does not expect this guidance to have a material impact on its consolidated financial statements. ASU No. 2017-04, Intangibles - Goodwill and Other (Topic 350) - Simplifying the Test for Goodwill Impairment. The Update eliminates Step 2 from the goodwill impairment analysis. Step 2, requires the Company to perform procedures to determine the fair value at the impairment testing date of its assets and liabilities (including unrecognized assets and liabilities). Under current guidance, Step 2 testing would be performed only if Step 1 testing indicated the fair value of the reporting unit is below the reporting unit’s carrying amount. Once effective the Update will require the Company to record an impairment charge for the amount by which the carrying amount exceeds the reporting unit’s fair value, eliminating the Step 2 requirements. The Company intends to adopt the Update for the first quarter of 2020. Adoption is not anticipated to have a material impact on the Company's financial statements. ASU No. 2016-15, Statement of Cash Flows (Topic 230) - Classification of Certain Cash Receipts and Cash Payments. The Update addresses eight specific cash flow issues with the objective of reducing the existing diversity in practice. The Update addresses the following eight issues: 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 intends to adopt the Update for the first quarter of 2018. The Company does not expect this 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. Current GAAP requires an "incurred loss" methodology for recognizing credit losses that delays recognition until it is probable a loss has been incurred. Both financial institutions and users of their financial statements expressed concern that current GAAP restricts the ability to record credit losses that are expected, but do not yet meet the "probable" threshold. 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 is likely to result in a material increase to the Company's accounting for credit losses on financial instruments. The Company has established a project lead and identified a working group comprised of members from different disciplines including Credit, Finance and Information Technology. The Company is in the early stages of evaluation of the effect that this ASU will have on its financial statements and related disclosures, but has begun to develop a roadmap which includes a consideration of external resources that may be required, use of existing and new models, data availability and system solutions to facilitate implementation. The ASU will be effective for the Company as of the first quarter 2020. While we are currently unable to reasonably estimate the impact of adopting the Update, we expect the impact of adoption will be significantly influenced by the composition, characteristics and quality of our loan and securities portfolios as well as the economic conditions as of the adoption date. ASU No. 2016-02, Leases (Topic 842). The Update introduces a lessee model that brings most leases on the balance sheet. The Update also aligns certain of the underlying principles of the new lessor model with those in ASC 606 "Revenue from Contracts with Customers", the FASB’s new revenue recognition standard (e.g., evaluating how collectability should be considered and determining when profit can be recognized). Furthermore, the Update addresses other concerns including the elimination of the required use of bright-line tests for determining lease classification. Lessors are required to provide additional transparency into the exposure to the changes in value of their residual assets and how they manage that exposure. The Company intends to adopt the Update for the first quarter of 2019 using the modified retrospective method. The Company is in the early assessment stage and will continue to review the existing lease portfolio to evaluate the impact of the new accounting guidance on the financial statements. ASU No. 2016-01, Financial Instruments - Overall (Subtopic 825-10) - Recognition and Measurement of Financial Assets and Financial Liabilities. Equity investments not accounted for under the equity method or those that do not result in consolidation of the investee are to be measured at fair value with changes in the fair value recognized through net income. Entities are to present separately in other comprehensive income, the portion of the total change in the fair value of a liability resulting from a change in the instrument-specific credit risk when an election to measure the liability at fair value in accordance with the fair value option for financial instruments has been made. Also, the requirement to disclose the method(s) and significant assumptions used to estimate the fair value for financial instruments measured at amortized cost on the balance sheet has been eliminated. The Company intends to adopt the Update for the first quarter of 2018. Adoption is not anticipated to have a material impact on the Company's financial statements. ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606). Also, subsequent ASUs issued to clarify this Topic. The Update requires an entity to recognize the amount of revenue to which it expects to be entitled for the transfer of promised goods or services to customers. The Update excludes the Company's revenue associated with net interest income, and certain non-interest income lines items (loan and lease related fees, mortgage banking activities, increase in cash surrender value of life insurance policies, gain on sale of investment securities, net, impairment loss on securities recognized in earnings, and a majority of other income). As a result a substantial amount of the Company's revenue will not be affected. The Company's deposit service fees, wealth and investment services, and certain other non-interest income items are within the scope of the Update. The Company's evaluation of the impacted revenue streams and associated customer contracts is near completion. While the assessment is not complete, the timing of the Company's revenue recognition is not expected to materially change. The disclosure objective of the Update is to provide users of the financial statement with sufficient information to understand the nature, amount, timing and uncertainty of revenue, certain costs, and cash flows arising from contracts with customers. The Company expects to provide expanded qualitative disclosure pertaining to significant judgments, accounting policy elections and the nature, timing, and uncertainty of revenue arising from contracts with customers. Further the Company expects to provide expanded quantitative disclosure pertaining to the disaggregation of revenue arising from contracts with customers. The Company continues to assess the impact of the changes in disclosure required by guidance.

Investment Securities

Investment Securities	9 Months Ended
	Sep. 30, 2017
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 September 30, 2017 At December 31, 2016 (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 $ 3,596 $ — $ — $ 3,596 $ 734 $ — $ — $ 734 Agency CMO 332,341 2,573 (3,116 ) 331,798 419,865 3,344 (3,503 ) 419,706 Agency MBS 923,819 3,214 (14,056 ) 912,977 969,460 4,398 (19,509 ) 954,349 Agency CMBS 599,165 — (14,205 ) 584,960 587,776 63 (14,567 ) 573,272 CMBS 402,015 1,539 (121 ) 403,433 473,974 4,093 (702 ) 477,365 CLO 273,172 1,572 (161 ) 274,583 425,083 2,826 (519 ) 427,390 Trust preferred 30,463 676 (202 ) 30,937 30,381 — (1,748 ) 28,633 Corporate debt 48,334 674 (130 ) 48,878 108,490 1,502 (350 ) 109,642 Available-for-sale $ 2,612,905 $ 10,248 $ (31,991 ) $ 2,591,162 $ 3,015,763 $ 16,226 $ (40,898 ) $ 2,991,091 Held-to-maturity: Agency CMO $ 276,367 $ 1,138 $ (3,030 ) $ 274,475 $ 339,455 $ 1,977 $ (3,824 ) $ 337,608 Agency MBS 2,549,500 24,275 (30,012 ) 2,543,763 2,317,449 26,388 (41,768 ) 2,302,069 Agency CMBS 708,229 280 (3,549 ) 704,960 547,726 694 (1,348 ) 547,072 Municipal bonds and notes 705,411 5,213 (13,150 ) 697,474 655,813 4,389 (25,749 ) 634,453 CMBS 257,361 3,394 (197 ) 260,558 298,538 4,107 (411 ) 302,234 Private Label MBS 443 2 — 445 1,677 12 — 1,689 Held-to-maturity $ 4,497,311 $ 34,302 $ (49,938 ) $ 4,481,675 $ 4,160,658 $ 37,567 $ (73,100 ) $ 4,125,125 Other-Than-Temporary Impairment The balance of OTTI, included in the amortized cost columns above, is 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. During the nine months ended September 30, 2017 , OTTI of $126 thousand , related to principal held back in conjunction with the exercise of a clean-up call option for a Private Label MBS security, was recognized. 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. The following table presents the changes in OTTI: Three months ended September 30, Nine months ended September 30, (In thousands) 2017 2016 2017 2016 Beginning balance $ 3,231 $ 3,437 $ 3,243 $ 3,288 Reduction for investment securities sold or called (1,028 ) (30 ) (1,166 ) (30 ) Additions for OTTI not previously recognized in earnings — — 126 149 Ending balance $ 2,203 $ 3,407 $ 2,203 $ 3,407 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 September 30, 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 $ 75,042 $ (1,002 ) $ 70,167 $ (2,114 ) 16 $ 145,209 $ (3,116 ) Agency MBS 464,031 (5,169 ) 303,770 (8,887 ) 104 767,801 (14,056 ) Agency CMBS 306,025 (6,240 ) 278,935 (7,965 ) 34 584,960 (14,205 ) CMBS 39,775 (121 ) — — 5 39,775 (121 ) CLO 82,989 (161 ) — — 5 82,989 (161 ) Trust preferred 12,570 (97 ) 4,574 (105 ) 3 17,144 (202 ) Corporate debt 5,797 (87 ) 1,825 (43 ) 2 7,622 (130 ) Available-for-sale in an unrealized loss position $ 986,229 $ (12,877 ) $ 659,271 $ (19,114 ) 169 $ 1,645,500 $ (31,991 ) Held-to-maturity: Agency CMO $ 82,839 $ (880 ) $ 83,103 $ (2,150 ) 19 $ 165,942 $ (3,030 ) Agency MBS 870,376 (7,948 ) 775,331 (22,064 ) 157 1,645,707 (30,012 ) Agency CMBS 570,781 (3,504 ) 4,730 (45 ) 45 575,511 (3,549 ) Municipal bonds and notes 123,965 (1,745 ) 226,545 (11,405 ) 140 350,510 (13,150 ) CMBS 40,150 (197 ) 250 — 5 40,400 (197 ) Held-to-maturity in an unrealized loss position $ 1,688,111 $ (14,274 ) $ 1,089,959 $ (35,664 ) 366 $ 2,778,070 $ (49,938 ) At December 31, 2016 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 $ 107,853 $ (2,168 ) $ 67,351 $ (1,335 ) 15 $ 175,204 $ (3,503 ) Agency MBS 512,075 (10,503 ) 252,779 (9,006 ) 97 764,854 (19,509 ) Agency CMBS 554,246 (14,567 ) — — 32 554,246 (14,567 ) CMBS 12,427 (24 ) 63,930 (678 ) 12 76,357 (702 ) CLO 49,946 (54 ) 50,237 (465 ) 5 100,183 (519 ) Trust preferred — — 28,633 (1,748 ) 5 28,633 (1,748 ) Corporate debt — — 7,384 (350 ) 2 7,384 (350 ) Available-for-sale in an unrealized loss position $ 1,236,547 $ (27,316 ) $ 470,314 $ (13,582 ) 168 $ 1,706,861 $ (40,898 ) Held-to-maturity: Agency CMO $ 163,439 $ (3,339 ) $ 17,254 $ (485 ) 16 $ 180,693 $ (3,824 ) Agency MBS 1,394,623 (32,942 ) 273,779 (8,826 ) 150 1,668,402 (41,768 ) Agency CMBS 347,725 (1,348 ) — — 25 347,725 (1,348 ) Municipal bonds and notes 384,795 (25,745 ) 1,192 (4 ) 196 385,987 (25,749 ) CMBS 60,768 (411 ) — — 8 60,768 (411 ) Held-to-maturity in an unrealized loss position $ 2,351,350 $ (63,785 ) $ 292,225 $ (9,315 ) 395 $ 2,643,575 $ (73,100 ) Impairment Analysis The following impairment analysis by investment security type, summarizes the basis for evaluating if investment securities within the Company’s available-for-sale and held-to-maturity portfolios have been impacted by OTTI. 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 these investment securities, in unrealized loss positions, to be other-than-temporarily impaired at September 30, 2017 . Available-for-Sale Agency CMO. There were unrealized losses of $3.1 million on the Company’s investment in Agency CMO at September 30, 2017 , compared to $3.5 million at December 31, 2016 . Unrealized losses decreased due to lower principal balances for this asset class at September 30, 2017 compared to December 31, 2016 . Market prices remained essentially unchanged. These investments are issued by a government agency or a government-sponsored agency and, therefore, are backed by certain government guarantees, either direct or indirect. The contractual cash flows for these investments are performing as expected, and there has been no change in the underlying credit quality. Agency MBS. There were unrealized losses of $14.1 million on the Company’s investment in Agency MBS at September 30, 2017 , compared to $19.5 million at December 31, 2016 . Unrealized losses decreased due to lower principal balances for this asset class at September 30, 2017 compared to December 31, 2016 . Market prices remained essentially unchanged. These investments are issued by a government agency or a government-sponsored agency and, therefore, are backed by certain government guarantees, either direct or indirect. The contractual cash flows for these investments are performing as expected, and there has been no change in the underlying credit quality. Agency CMBS. There were unrealized losses of $14.2 million on the Company's investment in Agency CMBS at September 30, 2017 , compared to $14.6 million at December 31, 2016 . Unrealized losses decreased while principal balances remained essentially unchanged. Market prices were slightly higher at September 30, 2017 compared to December 31, 2016 . These investments are issued by a government agency or a government-sponsored agency and, therefore, are backed by certain government guarantees, either direct or indirect. The contractual cash flows for these investments are performing as expected, and there has been no change in the underlying credit quality. CMBS. There were unrealized losses of $0.1 million on the Company’s investment in CMBS at September 30, 2017 , compared to $0.7 million at December 31, 2016 . The portfolio of mainly floating rate CMBS experienced lower principal balances and lower market spreads which resulted in higher security prices and smaller unrealized losses at September 30, 2017 compared to December 31, 2016 . Internal and external metrics are considered when evaluating potential OTTI. Internal stress tests are performed on individual bonds to monitor potential losses under stress scenarios. Contractual cash flows for these investments are performing as expected. CLO. There were unrealized losses of $0.2 million on the Company's investment in CLO at September 30, 2017 , compared to $0.5 million at December 31, 2016 . Unrealized losses decreased due to lower principal balances and lower market spreads for the CLO portfolio at September 30, 2017 compared to December 31, 2016 . Internal and external metrics are considered when evaluating potential OTTI. Contractual cash flows for these investments are performing as expected. Trust preferred. There were unrealized losses of $0.2 million on the Company's investment in trust preferred at September 30, 2017 , compared to $1.7 million at December 31, 2016 . Unrealized losses decreased due to lower market spreads for this asset class, which resulted in higher security prices compared to December 31, 2016 . The trust preferred portfolio consists of three floating rate investments issued by two different large capitalization money center financial institutions, which continue to service the debt. The Company performs periodic credit reviews of the issuer to assess the likelihood for ultimate recovery of amortized cost. Corporate debt. There were $0.1 million unrealized losses on the Company's corporate debt at September 30, 2017 , compared to $0.4 million at December 31, 2016 . Unrealized losses decreased due to lower principal balances for this asset class at September 30, 2017 compared to December 31, 2016 . Market prices remained essentially unchanged. The Company performs periodic credit reviews of the issuer to assess the likelihood for ultimate recovery of amortized cost. Held-to-Maturity Agency CMO. There were unrealized losses of $3.0 million on the Company’s investment in Agency CMO at September 30, 2017 compared to $3.8 million at December 31, 2016 . Unrealized losses decreased due to lower principal balances for this asset class at September 30, 2017 compared to December 31, 2016 . Market prices remained essentially unchanged. These investments are issued by a government agency or a government-sponsored agency and, therefore, are backed by certain government guarantees, either direct or indirect. The contractual cash flows for these investments are performing as expected, and there has been no change in the underlying credit quality. Agency MBS. There were unrealized losses of $30.0 million on the Company’s investment in Agency MBS at September 30, 2017 , compared to $41.8 million at December 31, 2016 . Unrealized losses decreased due to lower principal balances for this asset class at September 30, 2017 compared to December 31, 2016 . Market prices remained essentially unchanged. These investments are issued by a government agency or a government-sponsored agency and, therefore, are backed by certain government guarantees, either direct or indirect. There has been no change in the underlying credit quality, and the contractual cash flows are performing as expected. Agency CMBS. There were unrealized losses of $3.5 million on the Company's investment in Agency CMBS at September 30, 2017 , compared to $1.3 million at December 31, 2016 . Unrealized losses increased due to lower prices on recently purchased ACMBS as principal balances increased at September 30, 2017 compared to December 31, 2016 . These investments are issued by a government agency or a government-sponsored agency and, therefore, are backed by certain government guarantees, either direct or indirect. There has been no change in the underlying credit quality, and the contractual cash flows are performing as expected. Municipal bonds and notes. There were unrealized losses of $13.2 million on the Company’s investment in municipal bonds and notes at September 30, 2017 , compared to $25.7 million at December 31, 2016 . Unrealized losses decreased due to lower market rates which resulted in higher prices at September 30, 2017 . The Company performs periodic credit reviews of the issuers and these investments are currently performing as expected. CMBS. There were unrealized losses of $0.2 million on the Company’s investment in CMBS at September 30, 2017 , compared to $0.4 million at December 31, 2016 . Unrealized losses were approximately the same, for the portfolio comprised mainly of seasoned fixed rate conduit transactions, at September 30, 2017 compared to December 31, 2016 . Internal and external metrics are considered when evaluating potential OTTI. Internal stress tests are performed on individual bonds to monitor potential losses under stress scenarios. The contractual cash flows for these investments are performing as expected. Sales of Available-for Sale Investment Securities There were no sales during the three and nine months ended September 30, 2017 , or the three months ended September 30, 2016 . For the nine months ended September 30, 2016, there were sales resulting in proceeds of $259.3 million , with the related gross realized gains and gross realized losses of $2.9 million and $2.5 million , respectively. Contractual Maturities The amortized cost and fair value of debt securities by contractual maturity are set forth below: At September 30, 2017 Available-for-Sale Held-to-Maturity (In thousands) Amortized Cost Fair Value Amortized Cost Fair Value Due in one year or less $ 18,668 $ 18,714 $ 40,146 $ 40,753 Due after one year through five years 40,246 40,748 13,410 13,684 Due after five through ten years 381,547 383,721 38,323 39,102 Due after ten years 2,172,444 2,147,979 4,405,432 4,388,136 Total debt securities $ 2,612,905 $ 2,591,162 $ 4,497,311 $ 4,481,675 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 September 30, 2017 , the Company had a carrying value of $1.2 billion in callable investment 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 $2.8 billion at September 30, 2017 and $2.5 billion at December 31, 2016

Variable Interest Entities

Variable Interest Entities	9 Months Ended
	Sep. 30, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Variable Interest Entities	Variable Interest Entities The Company has an investment interest in several entities that meet the definition of a VIE. The following discussion provides information about the Company's VIEs. 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 Condensed 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 Condensed Consolidated Statements of Income. 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, CLO and trust preferred. 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 2: 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. At September 30, 2017 and December 31, 2016 , the aggregate carrying value of the Company's tax credit-finance investments were $35.7 million and $22.8 million , respectively. At September 30, 2017 and December 31, 2016 , unfunded commitments have been recognized, totaling $24.3 million and $14.0 million , respectively, and are included in accrued expenses and other liabilities in the accompanying Condensed Consolidated Balance Sheets. Webster Statutory Trust. The Company owns all of the outstanding common stock of Webster Statutory Trust, which is a financial vehicle that has issued, and may issue in the future, trust preferred securities. The trust is a VIE in which the Company is not the primary beneficiary and therefore, is not consolidated. 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 Condensed Consolidated Balance Sheets, and the related interest expense is reported as interest expense on long-term debt in the accompanying Condensed Consolidated Statements of Income. Other Investments. The Company invests in various alternative investments in which it holds a variable interest. Alternative 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 September 30, 2017 and December 31, 2016 , the aggregate carrying value of the Company's other investments in VIEs were $13.0 million and $12.3 million , respectively, and the total exposure of the Company's other investments in VIEs, including unfunded commitments, were $22.4 million and $19.9 million , respectively. The Company's equity interests in Tax Credit-Finance Investments, Webster Statutory Trust, and Other Investments are included in accrued interest receivable and other assets in the accompanying Condensed Consolidated Balance Sheets. For a further description of the Company's accounting policies regarding the consolidation of a VIE, refer to Note 1 to the Consolidated Financial Statements for the year ended December 31, 2016 included in its 2016

Loans and Leases

Loans and Leases	9 Months Ended
	Sep. 30, 2017
Loans and Leases Receivable Disclosure [Abstract]
Loans and Leases	Loans and Leases The following table summarizes loans and leases: (In thousands) At September 30, At December 31, 2016 Residential $ 4,499,441 $ 4,254,682 Consumer 2,566,983 2,684,500 Commercial 5,348,303 4,940,931 Commercial Real Estate 4,464,917 4,510,846 Equipment Financing 566,777 635,629 Loans and leases (1) (2) $ 17,446,421 $ 17,026,588 (1) Loans and leases include net deferred fees and net premiums/discounts of $20.8 million and $17.3 million at September 30, 2017 and December 31, 2016 , respectively. (2) At September 30, 2017 , the Company had pledged $6.7 billion of eligible residential, consumer and commercial loans as collateral to support borrowing capacity at the FHLB Boston and the FRB of Boston. Loans and Leases Aging The following tables summarize the aging of loans and leases: At September 30, 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 Residential $ 8,069 $ 3,654 $ — $ 45,676 $ 57,399 $ 4,442,042 $ 4,499,441 Consumer: Home equity 7,613 4,685 — 37,105 49,403 2,269,468 2,318,871 Other consumer 2,224 1,454 — 1,859 5,537 242,575 248,112 Commercial: Commercial non-mortgage 1,948 364 934 58,915 62,161 4,402,543 4,464,704 Asset-based — — — 8,558 8,558 875,041 883,599 Commercial real estate: Commercial real estate 1,347 444 — 10,603 12,394 4,161,572 4,173,966 Commercial construction — — — 477 477 290,474 290,951 Equipment financing 818 49 — 570 1,437 565,340 566,777 Total $ 22,019 $ 10,650 $ 934 $ 163,763 $ 197,366 $ 17,249,055 $ 17,446,421 At December 31, 2016 (In thousands) 30-59 Days 60-89 Days Past Due and Accruing 90 or More Days Past Due Non-accrual Total Past Due and Non-accrual Current Total Loans Residential $ 8,631 $ 2,609 $ — $ 47,279 $ 58,519 $ 4,196,163 $ 4,254,682 Consumer: Home equity 8,831 5,782 — 35,926 50,539 2,359,354 2,409,893 Other consumer 2,233 1,485 — 1,663 5,381 269,226 274,607 Commercial: Commercial non-mortgage 1,382 577 749 38,190 40,898 4,094,727 4,135,625 Asset-based — — — — — 805,306 805,306 Commercial real estate: Commercial real estate 6,357 1,816 — 9,871 18,044 4,117,742 4,135,786 Commercial construction — — — 662 662 374,398 375,060 Equipment financing 903 693 — 225 1,821 633,808 635,629 Total $ 28,337 $ 12,962 $ 749 $ 133,816 $ 175,864 $ 16,850,724 $ 17,026,588 Interest on non-accrual loans and leases that would have been recorded as additional interest income had the loans and leases been current in accordance with the original terms totaled $2.8 million and $3.7 million for the three months ended September 30, 2017 and 2016 , respectively, and $6.4 million and $8.4 million for the nine months ended September 30, 2017 and 2016 , 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 three months ended September 30, 2017 Residential Consumer Commercial Commercial Real Estate Equipment Financing Total ALLL: Balance, beginning of period $ 18,427 $ 42,488 $ 79,964 $ 52,402 $ 6,297 $ 199,578 (Benefit) provision charged to expense (348 ) (41 ) 12,166 (2,129 ) 502 10,150 Charge-offs (585 ) (6,197 ) (3,002 ) (749 ) (121 ) (10,654 ) Recoveries 280 1,894 466 10 79 2,729 Balance, end of period $ 17,774 $ 38,144 $ 89,594 $ 49,534 $ 6,757 $ 201,803 At or for the three months ended September 30, 2016 (In thousands) Residential Consumer Commercial Commercial Real Estate Equipment Financing Total ALLL: Balance, beginning of period $ 24,413 $ 42,956 $ 73,822 $ 33,622 $ 5,615 $ 180,428 Provision charged to expense 1,076 4,985 4,351 2,953 885 14,250 Charge-offs (1,304 ) (5,259 ) (2,561 ) — (300 ) (9,424 ) Recoveries 554 1,313 370 194 240 2,671 Balance, end of period $ 24,739 $ 43,995 $ 75,982 $ 36,769 $ 6,440 $ 187,925 At or for the nine months ended September 30, 2017 (In thousands) Residential Consumer Commercial Commercial Real Estate Equipment Financing Total ALLL: Balance, beginning of period $ 23,226 $ 45,233 $ 71,905 $ 47,477 $ 6,479 $ 194,320 (Benefit) provision charged to expense (4,436 ) 6,847 21,905 2,987 597 27,900 Charge-offs (1,940 ) (18,273 ) (5,321 ) (951 ) (425 ) (26,910 ) Recoveries 924 4,337 1,105 21 106 6,493 Balance, end of period $ 17,774 $ 38,144 $ 89,594 $ 49,534 $ 6,757 $ 201,803 Individually evaluated for impairment $ 4,925 $ 1,689 $ 10,844 $ 290 $ 38 $ 17,786 Collectively evaluated for impairment $ 12,849 $ 36,455 $ 78,750 $ 49,244 $ 6,719 $ 184,017 Loan and lease balances: Individually evaluated for impairment $ 116,706 $ 46,224 $ 85,385 $ 18,199 $ 3,642 $ 270,156 Collectively evaluated for impairment 4,382,735 2,520,759 5,262,918 4,446,718 563,135 17,176,265 Loans and leases $ 4,499,441 $ 2,566,983 $ 5,348,303 $ 4,464,917 $ 566,777 $ 17,446,421 At or for the nine months ended September 30, 2016 (In thousands) Residential Consumer Commercial Commercial Real Estate Equipment Financing Total ALLL: Balance, beginning of period $ 25,876 $ 42,052 $ 66,686 $ 34,889 $ 5,487 $ 174,990 Provision charged to expense 991 12,458 25,447 3,921 1,033 43,850 Charge-offs (3,536 ) (14,236 ) (17,294 ) (2,521 ) (521 ) (38,108 ) Recoveries 1,408 3,721 1,143 480 441 7,193 Balance, end of period $ 24,739 $ 43,995 $ 75,982 $ 36,769 $ 6,440 $ 187,925 Individually evaluated for impairment $ 9,443 $ 3,005 $ 6,579 $ 467 $ 9 $ 19,503 Collectively evaluated for impairment $ 15,296 $ 40,990 $ 69,403 $ 36,302 $ 6,431 $ 168,422 Loan and lease balances: Individually evaluated for impairment $ 122,020 $ 46,208 $ 58,197 $ 24,423 $ 6,863 $ 257,711 Collectively evaluated for impairment 4,112,027 2,661,135 4,721,605 4,256,090 614,833 16,365,690 Loans and leases $ 4,234,047 $ 2,707,343 $ 4,779,802 $ 4,280,513 $ 621,696 $ 16,623,401 Impaired Loans and Leases The following tables summarize impaired loans and leases: At September 30, 2017 (In thousands) Unpaid Principal Balance Total Recorded Investment No Allowance Recorded Investment With Allowance Related Valuation Allowance Residential $ 127,986 $ 116,706 $ 27,961 $ 88,745 $ 4,925 Consumer - home equity 51,496 46,225 21,833 24,392 1,689 Commercial : Commercial non-mortgage 88,221 76,827 28,124 48,703 10,844 Asset-based 8,558 8,558 8,558 — — Commercial real estate: Commercial real estate 19,026 17,725 12,894 4,831 271 Commercial construction 580 474 — 474 19 Equipment financing 3,721 3,642 3,004 638 38 Total $ 299,588 $ 270,157 $ 102,374 $ 167,783 $ 17,786 At December 31, 2016 (In thousands) Unpaid Principal Balance Total Recorded Investment No Allowance Recorded Investment With Allowance Related Valuation Allowance Residential $ 131,468 $ 119,424 $ 21,068 $ 98,356 $ 8,090 Consumer - home equity 52,432 45,719 22,746 22,973 2,903 Commercial : Commercial non-mortgage 57,732 53,037 26,006 27,031 7,422 Asset-based — — — — — Commercial real estate: Commercial real estate 24,146 23,568 19,591 3,977 169 Commercial construction 1,188 1,187 1,187 — — Equipment financing 6,398 6,420 6,197 223 9 Total $ 273,364 $ 249,355 $ 96,795 $ 152,560 $ 18,593 The following table summarizes the average recorded investment and interest income recognized for impaired loans and leases: Three months ended September 30, Nine months ended September 30, 2017 2016 2017 2016 (In thousands) Average Recorded Investment Accrued Interest Income Cash Basis Interest Income Average Accrued Cash Basis Interest Income Average Recorded Investment Accrued Cash Basis Interest Income Average Recorded Investment Accrued Cash Basis Interest Income Residential $ 118,841 $ 1,027 $ 285 $ 124,993 $ 1,070 $ 304 $ 118,065 $ 3,133 $ 986 $ 128,234 $ 3,309 $ 918 Consumer - home equity 46,753 341 246 46,892 336 238 45,972 998 808 47,317 1,029 754 Commercial Commercial Non-Mortgage 81,816 249 — 58,874 352 — 64,932 704 — 57,389 1,299 — Asset based 4,279 — — — — — 4,279 — — — — Commercial real estate: Commercial real estate 20,249 96 — 23,930 77 — 20,647 329 — 26,689 374 — Commercial construction 828 — — 4,386 12 — 831 12 — 5,171 81 — Equipment financing 4,895 30 — 3,642 107 — 5,031 168 — 3,642 109 — Total $ 277,661 $ 1,743 $ 531 $ 262,717 $ 1,954 $ 542 $ 259,757 $ 5,344 $ 1,794 $ 268,442 $ 6,201 $ 1,672 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 probability of borrower default and the loss given default. 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 default. 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 borrower's 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 (In thousands) At September 30, At December 31, At September 30, At December 31, At September 30, At December 31, (1) - (6) Pass $ 5,037,439 $ 4,655,007 $ 4,266,658 $ 4,357,458 $ 548,298 $ 618,084 (7) Special Mention 108,828 56,240 85,926 69,023 3,557 1,324 (8) Substandard 192,161 226,603 112,333 84,365 14,922 16,221 (9) Doubtful 9,875 3,081 — — — — Total $ 5,348,303 $ 4,940,931 $ 4,464,917 $ 4,510,846 $ 566,777 $ 635,629 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 both 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 trend 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: (Dollars in thousands) At September 30, At December 31, 2016 Accrual status $ 135,774 $ 147,809 Non-accrual status 82,576 75,719 Total recorded investment of TDRs $ 218,350 $ 223,528 Specific reserves for TDRs included in the balance of ALLL $ 11,837 $ 14,583 Additional funds committed to borrowers in TDR status 3,944 459 For the portion of TDRs deemed to be uncollectible, Webster charged off $0.4 million and $3.0 million for the three months ended September 30, 2017 and 2016 , respectively, and $3.0 million , and $17.9 million for the nine months ended September 30, 2017 and 2016 , respectively. The following table provides information on the type of concession for loans and leases modified as TDRs: Three months ended September 30, Nine months ended September 30, 2017 2016 2017 2016 Number of Post- (1) Number of Post- (1) Number of Post- (1) Number of Post- (1) (Dollars in thousands) Residential: Extended Maturity — $ — 4 $ 967 9 $ 1,390 11 $ 1,969 Adjusted Interest Rate — — 1 292 2 335 2 528 Maturity/Rate Combined 4 570 3 290 9 1,416 10 1,185 Other (2) 6 1,357 3 299 32 5,471 18 3,190 Consumer - home equity Extended Maturity 2 158 2 89 8 822 9 381 Adjusted Interest Rate 1 247 — — 1 247 — — Maturity/Rate Combined 2 399 3 264 13 3,212 11 923 Other (2) 12 839 8 270 55 3,733 37 1,447 Commercial non - mortgage Extended Maturity — — 2 213 8 813 11 14,862 Maturity/Rate Combined 8 299 — — 13 9,153 2 648 Other (2) — — 4 1,265 1 4 11 1,639 Commercial real estate: Extended Maturity — — 1 109 — — 1 109 Maturity/Rate Combined — — 1 291 — — 2 335 Other (2) — — — — — — 1 509 Equipment Financing Extended Maturity — — 6 6,638 — — 7 6,642 Total TDRs 35 $ 3,869 38 $ 10,987 151 $ 26,596 133 $ 34,367 (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, or other concessions. Loans and leases modified as TDRs within the previous 12 months and for which there was a payment default, consisted of one residential loan with a recorded investment of $248 thousand for both the three and nine months ended September 30, 2017. There were no such loans and leases for both the three and nine months ended September 30, 2016. The recorded investment of TDRs in commercial, commercial real estate, and equipment financing segregated by risk rating exposure is as follows: (In thousands) At September 30, 2017 At December 31, 2016 (1) - (6) Pass $ 8,902 $ 10,210 (7) Special Mention 360 7 (8) Substandard 46,157 45,509 (9) Doubtful — 2,738 Total $ 55,419 $ 58,464

Transfers of Financial Assets

Transfers of Financial Assets	9 Months Ended
	Sep. 30, 2017
Transfers and Servicing [Abstract]
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. The gain or loss on residential mortgage loans sold and the related origination fee income, and the fair value adjustment to loans held-for-sale are included as mortgage banking activities in the accompanying Condensed 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 management’s evaluation of the identity of the 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 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 also may impact the reserve. 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 Condensed Consolidated Statements of Income. The following table provides a summary of activity in the reserve for loan repurchases: Three months ended September 30, Nine months ended September 30, (In thousands) 2017 2016 2017 2016 Beginning balance $ 843 $ 992 $ 790 $ 1,192 Provision (benefit) charged to expense 25 37 78 (64 ) Repurchased loans and settlements charged off (18 ) — (18 ) (99 ) Ending balance $ 850 $ 1,029 $ 850 $ 1,029 The following table provides information for mortgage banking activities: Three months ended September 30, Nine months ended September 30, (In thousands) 2017 2016 2017 2016 Residential mortgage loans held for sale: Proceeds from sale $ 88,691 $ 128,268 $ 262,029 $ 298,840 Loans sold with servicing rights retained 79,690 115,822 239,357 273,827 Net gain on sale 1,979 3,324 4,356 6,749 Ancillary fees 682 1,046 2,091 2,485 Fair value option adjustment (240 ) (48 ) 1,591 2,101 The Company has retained servicing rights on residential mortgage loans totaling $2.6 billion at both September 30, 2017 and December 31, 2016 . The following table presents the changes in carrying value for mortgage servicing assets: Three months ended September 30, Nine months ended September 30, (In thousands) 2017 2016 2017 2016 Beginning balance $ 24,708 $ 21,946 $ 24,466 $ 20,698 Additions 2,576 3,338 7,063 8,198 Amortization (2,144 ) (1,900 ) (6,389 ) (5,512 ) Ending balance $ 25,140 $ 23,384 $ 25,140 $ 23,384 Loan servicing fees, net of mortgage servicing rights amortization, were $0.2 million and $0.3 million for the three months ended September 30, 2017 and 2016 , respectively, and $0.6 million and $0.9 million for the nine months ended September 30, 2017 and 2016 , respectively, and are included as a component of loan related fees in the accompanying Condensed Consolidated Statements of Income. See Note 13: Fair Value Measurements for a further discussion on the fair value of loans held for sale and mortgage servicing assets. Additionally, loans not originated for sale were sold approximately at carrying value, for cash proceeds of $7.4 million for certain residential loans and $20.8 million for certain commercial loans for the nine months ended September 30, 2017 and 2016

Goodwill and Other Intangible A

Goodwill and Other Intangible Assets	9 Months Ended
	Sep. 30, 2017
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 September 30, 2017 At December 31, 2016 (In thousands) Gross Carrying Amount Accumulated Amortization Net Carrying Amount Gross Carrying Amount Accumulated Amortization Net Carrying Amount Other intangible assets: HSA Bank CDI $ 22,000 $ (8,036 ) $ 13,964 $ 22,000 $ (6,162 ) $ 15,838 HSA Bank Customer relationships 21,000 (4,375 ) 16,625 21,000 (3,164 ) 17,836 Total other intangible assets $ 43,000 $ (12,411 ) $ 30,589 $ 43,000 $ (9,326 ) $ 33,674 Goodwill: Community Banking $ 516,560 $ 516,560 HSA Bank 21,813 21,813 Total goodwill $ 538,373 $ 538,373 There was no change in the carrying amounts for goodwill since December 31, 2016 . As of September 30, 2017 , the remaining estimated aggregate future amortization expense for intangible assets is as follows: (In thousands) Remainder of 2017 $ 978 2018 3,847 2019 3,847 2020 3,847 2021 3,847 Thereafter 14,223

Deposits

Deposits	9 Months Ended
	Sep. 30, 2017
Banking and Thrift [Abstract]
Deposits	Deposits A summary of deposits by type follows: (In thousands) At September 30, At December 31, Non-interest-bearing: Demand $ 4,138,206 $ 4,021,061 Interest-bearing: Checking 2,581,266 2,528,274 Health savings accounts 4,891,024 4,362,503 Money market 2,598,187 2,047,121 Savings 4,428,061 4,320,090 Time deposits 2,218,491 2,024,808 Total interest-bearing 16,717,029 15,282,796 Total deposits $ 20,855,235 $ 19,303,857 Time deposits and interest-bearing checking, included in above balances, obtained through brokers $ 913,042 $ 848,618 Time deposits, included in above balance, that meet or exceed the FDIC limit 613,012 490,721 Deposit overdrafts reclassified as loan balances 2,494 1,885 The scheduled maturities of time deposits are as follows: (In thousands) At September 30, Remainder of 2017 $ 285,203 2018 952,745 2019 607,952 2020 225,159 2021 107,921 Thereafter 39,511 Total time deposits $ 2,218,491

Borrowings

Borrowings	9 Months Ended
	Sep. 30, 2017
Debt Disclosure [Abstract]
Borrowings	Borrowings Total borrowings of $2.6 billion at September 30, 2017 and $4.0 billion at December 31, 2016 are described in detail below. The following table summarizes securities sold under agreements to repurchase and other borrowings: At September 30, At December 31, (In thousands) Amount Rate Amount Rate Securities sold under agreements to repurchase: Original maturity of one year or less $ 335,902 0.18 % $ 340,526 0.16 % Original maturity of greater than one year, non-callable 400,000 3.04 400,000 3.09 Total securities sold under agreements to repurchase 735,902 1.73 740,526 1.82 Fed funds purchased 167,000 1.12 209,000 0.46 Securities sold under agreements to repurchase and other borrowings $ 902,902 1.62 % $ 949,526 1.53 % Repurchase agreements are used as a source of borrowed funds and are collateralized by U.S. Government agency mortgage-backed securities. Repurchase agreement 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 September 30, At December 31, (Dollars in thousands) Amount Weighted- Average Contractual Coupon Rate Amount Weighted- Average Contractual Coupon Rate Maturing within 1 year $ 880,500 1.28 % $ 2,130,500 0.71 % After 1 but within 2 years 133,731 1.34 200,000 1.36 After 2 but within 3 years 259,295 1.79 128,026 1.73 After 3 but within 4 years 75,000 1.51 175,000 1.77 After 4 but within 5 years 150,061 2.23 200,000 1.81 After 5 years 9,091 2.61 9,370 2.59 1,507,678 1.49 % 2,842,896 0.95 % Premiums on advances 3 12 Federal Home Loan Bank advances $ 1,507,681 $ 2,842,908 Aggregate carrying value of assets pledged as collateral $ 6,388,102 $ 5,967,318 Remaining borrowing capacity 2,668,964 1,192,758 Webster Bank is 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: (Dollars in thousands) At September 30, At December 31, 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 (756 ) (845 ) Debt issuance cost on senior fixed-rate notes (860 ) (961 ) Long-term debt $ 225,704 $ 225,514 (1) The interest rate on Webster Statutory Trust I floating-rate notes, which varies quarterly based on 3-month LIBOR plus 2.95% , was 4.27% at September 30, 2017 and 3.94% at December 31, 2016

Accumulated Other Comprehensive

Accumulated Other Comprehensive Loss, Net of Tax	9 Months Ended
	Sep. 30, 2017
Equity [Abstract]
Accumulated Other Comprehensive Loss, Net of Tax	Accumulated Other Comprehensive Loss, Net of Tax The following tables summarize the changes in AOCL by component: Three months ended September 30, 2017 Nine months ended September 30, 2017 (In thousands) Securities Available For Sale and Transferred Derivative Instruments Defined Benefit Pension and Other Postretirement Benefit Plans Total Securities Available For Sale and Transferred Derivative Instruments Defined Benefit Pension and Other Postretirement Benefit Plans Total Beginning balance $ (14,501 ) $ (15,258 ) $ (42,323 ) $ (72,082 ) $ (15,476 ) $ (17,068 ) $ (44,449 ) $ (76,993 ) OCI/OCL before reclassifications 872 (34 ) — 838 1,847 (445 ) — 1,402 Amounts reclassified from AOCL — 1,145 1,001 2,146 — 3,366 3,127 6,493 Net current-period OCI/OCL 872 1,111 1,001 2,984 1,847 2,921 3,127 7,895 Ending balance $ (13,629 ) $ (14,147 ) $ (41,322 ) $ (69,098 ) $ (13,629 ) $ (14,147 ) $ (41,322 ) $ (69,098 ) Three months ended September 30, 2016 Nine months ended September 30, 2016 (In thousands) Securities Available For Sale and Transferred Derivative Instruments Defined Benefit Pension and Other Postretirement Benefit Plans Total Securities Available For Sale and Transferred Derivative Instruments Defined Benefit Pension and Other Postretirement Benefit Plans Total Beginning balance $ 12,363 $ (23,406 ) $ (46,468 ) $ (57,511 ) $ (6,407 ) $ (22,980 ) $ (48,719 ) $ (78,106 ) OCI/OCL before reclassifications 1,218 794 — 2,012 20,156 (2,416 ) — 17,740 Amounts reclassified from AOCL — 1,221 1,125 2,346 (168 ) 4,005 3,376 7,213 Net current-period OCI/OCL 1,218 2,015 1,125 4,358 19,988 1,589 3,376 24,953 Ending balance $ 13,581 $ (21,391 ) $ (45,343 ) $ (53,153 ) $ 13,581 $ (21,391 ) $ (45,343 ) $ (53,153 ) The following tables provide information for the items reclassified from AOCL: (In thousands) Three months ended September 30, Nine months ended September 30, Associated Line Item in the Condensed Consolidated Statements of Income AOCL Components 2017 2016 2017 2016 Securities available-for-sale and transferred: Unrealized gains (losses) on investment securities $ — $ — $ — $ 414 Gain on sale of investment securities, net Unrealized gains (losses) on investment securities — — — (149 ) Impairment loss recognized in earnings Total before tax — — — 265 Tax benefit (expense) — — — (97 ) Income tax expense Net of tax $ — $ — $ — $ 168 Derivative instruments: Cash flow hedges $ (1,810 ) $ (1,925 ) $ (5,316 ) $ (6,314 ) Total interest expense Tax benefit 665 704 1,950 2,309 Income tax expense Net of tax $ (1,145 ) $ (1,221 ) $ (3,366 ) $ (4,005 ) Defined benefit pension and other postretirement benefit plans: Amortization of net loss $ (1,587 ) $ (1,780 ) $ (4,959 ) $ (5,343 ) (1) Prior service costs — (4 ) — (11 ) (1) Total before tax (1,587 ) (1,784 ) (4,959 ) (5,354 ) Tax benefit 586 659 1,832 1,978 Income tax expense Net of tax $ (1,001 ) $ (1,125 ) $ (3,127 ) $ (3,376 )

Regulatory Matters

Regulatory Matters	9 Months Ended
	Sep. 30, 2017
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. 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, other intangibles, and certain deferred tax liabilities. 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: At September 30, 2017 Actual Minimum Requirement Well Capitalized (Dollars in thousands) Amount Ratio Amount Ratio Amount Ratio Webster Financial Corporation CET1 risk-based capital $ 2,031,955 10.99 % $ 832,149 4.5 % $ 1,201,993 6.5 % Total risk-based capital 2,436,332 13.17 1,479,376 8.0 1,849,220 10.0 Tier 1 risk-based capital 2,154,665 11.65 1,109,532 6.0 1,479,376 8.0 Tier 1 leverage capital 2,154,665 8.36 1,030,973 4.0 1,288,717 5.0 Webster Bank CET1 risk-based capital $ 2,061,764 11.16 % $ 831,319 4.5 % $ 1,200,794 6.5 % Total risk-based capital 2,266,110 12.27 1,477,900 8.0 1,847,376 10.0 Tier 1 risk-based capital 2,061,764 11.16 1,108,425 6.0 1,477,900 8.0 Tier 1 leverage capital 2,061,764 8.00 1,030,260 4.0 1,287,825 5.0 At December 31, 2016 Actual Minimum Requirement Well Capitalized (Dollars in thousands) Amount Ratio Amount Ratio Amount Ratio Webster Financial Corporation CET1 risk-based capital $ 1,932,171 10.52 % $ 826,504 4.5 % $ 1,193,840 6.5 % Total risk-based capital 2,328,808 12.68 1,469,341 8.0 1,836,677 10.0 Tier 1 risk-based capital 2,054,881 11.19 1,102,006 6.0 1,469,341 8.0 Tier 1 leverage capital 2,054,881 8.13 1,010,857 4.0 1,263,571 5.0 Webster Bank CET1 risk-based capital $ 1,945,332 10.61 % $ 825,228 4.5 % $ 1,191,995 6.5 % Total risk-based capital 2,141,939 11.68 1,467,071 8.0 1,833,839 10.0 Tier 1 risk-based capital 1,945,332 10.61 1,100,304 6.0 1,467,071 8.0 Tier 1 leverage capital 1,945,332 7.70 1,010,005 4.0 1,262,507 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. In addition, the OCC has discretion to prohibit any otherwise permitted capital distribution on general safety and soundness grounds. Dividends paid by Webster Bank to Webster Financial Corporation totaled $80 million during the nine months ended September 30, 2017 compared to $115 million during the nine months ended September 30, 2016 . Cash Restrictions Webster Bank is required by Federal Reserve System regulations to hold cash reserve balances on hand or with the Federal Reserve Bank. Pursuant to this requirement, Webster Bank held $76.7 million and $58.6 million at September 30, 2017 and December 31, 2016

Earnings Per Common Share

Earnings Per Common Share	9 Months Ended
	Sep. 30, 2017
Earnings Per Share [Abstract]
Earnings Per Common Share	Earnings Per Common Share Reconciliation of the calculation of basic and diluted earnings per common share follows: Three months ended September 30, Nine months ended September 30, (In thousands, except per share data) 2017 2016 2017 2016 Earnings for basic and diluted earnings per common share: Net income $ 64,496 $ 51,817 $ 185,546 $ 149,467 Less: Preferred stock dividends 2,024 2,024 6,072 6,072 Net income available to common shareholders 62,472 49,793 179,474 143,395 Less: Earnings applicable to participating securities 46 159 212 468 Earnings applicable to common shareholders $ 62,426 $ 49,634 $ 179,262 $ 142,927 Shares: Weighted-average common shares outstanding - basic 92,125 91,365 92,003 91,298 Effect of dilutive securities: Stock options and restricted stock 372 465 403 452 Warrants 6 27 6 26 Weighted-average common shares outstanding - diluted 92,503 91,857 92,412 91,776 Earnings per common share: Basic $ 0.68 $ 0.54 $ 1.95 $ 1.57 Diluted 0.67 0.54 1.94 1.56 Potential common shares excluded from the effect of dilutive securities because they would have been anti-dilutive, are as follows: Three months ended September 30, Nine months ended September 30, (In thousands) 2017 2016 2017 2016 Stock options (shares with exercise price greater than market price) — 172 — 172 Restricted stock (due to performance conditions on non-participating shares) 80 — 61 161

Derivative Financial Instrument

Derivative Financial Instruments	9 Months Ended
	Sep. 30, 2017
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Financial Instruments	Derivative Financial Instruments Risk Management Objective of Using Derivatives Webster manages economic risks, such as interest rate, liquidity, and credit risks 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 future receipt or payment of, both 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 fair value of the 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 any 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 Condensed 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. RPAs 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, 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, or 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. Fair Value of Derivative Instruments The following table presents the notional amounts and fair values of derivative positions: At September 30, 2017 At December 31, 2016 Asset Derivatives Liability Derivatives Asset Derivatives Liability Derivatives (In thousands) Notional Fair Notional Fair Notional Fair Notional Fair Designated as hedging instruments: Positions subject to a master netting agreement (1) Interest rate derivatives $ 225,000 $ 1,972 $ 100,000 $ 195 $ 225,000 $ 3,270 $ 100,000 $ 792 Not designated as hedging instruments: Positions subject to a master netting agreement (1) Interest rate derivatives 2,270,444 4,225 1,125,953 3,224 1,943,485 32,226 1,242,937 24,388 Other 8,595 260 22,161 419 10,634 231 14,265 120 Positions not subject to a master netting agreement Interest rate derivatives 1,738,527 35,065 1,652,004 15,764 1,734,679 38,668 1,451,762 19,001 RPAs 94,103 112 99,538 136 86,037 139 87,273 166 Mortgage banking derivatives (2) 42,290 614 60,698 128 103,440 3,084 59,895 711 Other 262 2 1,777 157 1,438 19 181 11 Total not designated as hedging instruments 4,154,221 40,278 2,962,131 19,828 3,879,713 74,367 2,856,313 44,397 Gross derivative instruments, before netting $ 4,379,221 42,250 $ 3,062,131 20,023 $ 4,104,713 77,637 $ 2,956,313 45,189 Less: Legally enforceable master netting agreements 2,915 2,916 24,252 24,254 Less: Cash collateral posted 2,540 766 11,475 600 Total derivative instruments, after netting $ 36,795 $ 16,341 $ 41,910 $ 20,335 (1) One of Webster's counterparty relationships was impacted by a Chicago Mercantile Exchange rulebook amendment, resulting in the presentation of that relationship on a settlement basis, as a single unit of account at September 30, 2017 , versus a netting basis at December 31, 2016. (2) Notional amounts include mandatory forward commitments of $60.5 million , while notional amounts do not include approved floating rate commitments of $21.9 million , at September 30, 2017 . Changes in Fair Value Changes in the fair value of derivatives not qualifying for hedge accounting treatment were recognized as follows: Three months ended September 30, Nine months ended September 30, (In thousands) 2017 2016 2017 2016 Interest rate derivatives $ 1,501 $ 608 $ 1,780 $ 6,515 RPAs 51 110 157 (143 ) Mortgage banking derivatives (219 ) 720 (1,886 ) 357 Other (7 ) (285 ) (634 ) (582 ) Total impact on other non-interest income $ 1,326 $ 1,153 $ (583 ) $ 6,147 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 $1.2 million will be reclassified from AOCL as an increase to interest expense. Webster records gains and losses related to hedge terminations to AOCL. These balances are subsequently amortized into interest expense over the respective terms of the hedged debt instruments. At September 30, 2017 , the remaining unamortized loss on the termination of cash flow hedges is $16.5 million . Over the next twelve months, the Company estimates that $6.4 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 9: Accumulated Other Comprehensive Loss, Net of Tax . Information about the valuation methods used to measure the fair value of derivatives is provided in Note 13: Fair Value Measurements . Offsetting Derivatives Webster has entered into transactions with counterparties that are subject to a legally enforceable master netting agreement. 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 Condensed Consolidated Balance Sheets. The following table is presented on a gross basis, prior to the application of counterparty netting agreements: At September 30, 2017 At December 31, 2016 (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 $ 1,972 $ 292 $ 1,051 $ 629 $ 3,270 $ 2,335 $ 935 $ — Non-hedge accounting 4,452 2,623 1,489 340 32,457 21,917 10,540 — Total assets $ 6,424 $ 2,915 $ 2,540 $ 969 $ 35,727 $ 24,252 $ 11,475 $ — Derivative instrument losses: Hedge accounting $ 195 $ 195 $ — $ — $ 792 $ 792 $ — $ — Non-hedge accounting 3,643 2,721 766 156 24,508 23,462 600 446 Total liabilities $ 3,838 $ 2,916 $ 766 $ 156 $ 25,300 $ 24,254 $ 600 $ 446 Counterparty Credit Risk Use of derivative contracts may expose the bank to counterparty credit risk. The Company has ISDA master agreements, including a Credit Support Annex, with all derivative counterparties. The ISDA master agreements provide that on each payment date, all amounts otherwise owing the same currency under the same transaction are netted so that only a single amount is owed in that currency. The ISDA provides, if the parties so elect, for such netting of amounts in the same currency among all transactions identified as being subject to such election that have common payment dates and booking offices. Under the Credit Support Annex, daily net exposure in excess of a negotiated threshold is secured by posted cash collateral. The Company has negotiated a zero threshold with the majority of its approved financial institution counterparties. In accordance with Webster policies, institutional counterparties must be analyzed and approved through the Company’s credit approval process. The Company’s credit exposure on interest rate derivatives with non-dealer counterparties is limited to the net favorable value, including accrued interest, of all such instruments, reduced by the amount of collateral pledged by the counterparties. The Company's credit exposure related to derivatives with dealer counterparties is significantly mitigated with cash collateral equal to, or in excess of, the market value of the instrument updated daily. In accordance with counterparty credit agreements and derivative clearing rules, the Company had approximately $20.7 million in net margin collateral posted with financial counterparties at September 30, 2017 , comprised of $30.5 million in initial margin and $9.8 million in variation margin collateral received from financial counterparties or the derivative clearing organization. Collateral levels for approved financial institution counterparties are monitored daily and adjusted as necessary. In the event of default, should the collateral not be returned, the exposure would be offset by terminating the transaction. The Company regularly evaluates the credit risk of its counterparties, taking into account the likelihood of default, net exposures, and remaining contractual life, among other related factors. The Company's net current credit exposure relating to interest rate derivatives with Webster Bank customers was $35.1 million at September 30, 2017 . 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 $27.7 million at September 30, 2017

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2017
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 or unexpected. Available-for-Sale investment securities which include Agency CMO, Agency MBS, Agency CMBS, CMBS, CLO, 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. Derivative instruments are valued using third-party valuation software, which considers the present value of cash flows discounted using observable forward rate assumptions. The Chicago Mercantile Exchange have amended their rulebooks to legally characterize variation margin payments for over-the-counter derivatives that clear as settlements rather than collateral, effective January 3, 2017. One of Webster's counterparty relationships was impacted by this change, resulting in the fair value of the instrument including cash collateral as a single unit of account. 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. Webster reviews its counterparty exposure on a regular basis, and, when necessary, appropriate business actions are taken to adjust 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 change in value of derivative assets and liabilities attributable to credit risk was not significant during the reported periods. 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. 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 $2.9 million at September 30, 2017 . Alternative Investments. Alternative investments are non-public entities that cannot be redeemed since the Company’s investment is distributed as the underlying equity is liquidated. Alternative investments in which the ownership percentage is greater than 3% are fair valued on a recurring basis based upon the net asset value of the respective fund. Alternative investments in which the ownership percentage is less than 3% are fair valued on a non-recurring basis. These alternative investments are recorded at cost, subject to impairment testing. Both recurring and non-recurring alternative investments are classified within Level 3 of the fair value hierarchy, as they are non-public entities that cannot be redeemed since the Company's investment is distributed as the underlying investments are liquidated. At September 30, 2017 , the alternative investments book value was $17.3 million and there was $9.4 million in remaining unfunded commitments. 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 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. Summaries of the fair values of assets and liabilities measured at fair value on a recurring basis are as follows: At September 30, 2017 (In thousands) Level 1 Level 2 Level 3 Total Financial assets held at fair value: U.S. Treasury Bills $ 3,596 $ — $ — $ 3,596 Agency CMO — 331,798 — 331,798 Agency MBS — 912,977 — 912,977 Agency CMBS — 584,960 — 584,960 CMBS — 403,433 — 403,433 CLO — 274,583 — 274,583 Trust preferred — 30,937 — 30,937 Corporate debt — 48,878 — 48,878 Total available-for-sale investment securities 3,596 2,587,566 — 2,591,162 Gross derivative instruments, before netting (1) 262 41,988 — 42,250 Investments held in Rabbi Trust 5,278 — — 5,278 Alternative investments — — 6,986 6,986 Originated loans held for sale — 32,855 — 32,855 Total financial assets held at fair value $ 9,136 $ 2,662,409 $ 6,986 $ 2,678,531 Financial liabilities held at fair value: Gross derivative instruments, before netting (1) $ 562 $ 19,461 $ — $ 20,023 At December 31, 2016 (In thousands) Level 1 Level 2 Level 3 Total Financial assets held at fair value: U.S. Treasury Bills $ 734 $ — $ — $ 734 Agency CMO — 419,706 — 419,706 Agency MBS — 954,349 — 954,349 Agency CMBS — 573,272 — 573,272 CMBS — 477,365 — 477,365 CLO — 427,390 — 427,390 Trust preferred — 28,633 — 28,633 Corporate debt — 109,642 — 109,642 Total available-for-sale investment securities 734 2,990,357 — 2,991,091 Gross derivative instruments, before netting (1) 250 77,387 — 77,637 Investments held in Rabbi Trust 5,119 — — 5,119 Alternative investments — — 5,502 5,502 Originated loans held for sale — 60,260 — 60,260 Total financial assets held at fair value $ 6,103 $ 3,128,004 $ 5,502 $ 3,139,609 Financial liabilities held at fair value: Gross derivative instruments, before netting (1) $ 120 $ 45,069 $ — $ 45,189 (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 12: Derivative Financial Instruments . The following table presents the changes in Level 3 assets and liabilities that are measured at fair value on a recurring basis: (In thousands) Alternative Investments Balance at January 1, 2017 $ 5,502 Unrealized gain included in net income 639 Purchases/capital funding 899 Payments (54 ) Balance at September 30, 2017 $ 6,986 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. 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 is primarily commercial loans with observable inputs and is classified within Level 2. On the occasion should these loans 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 $5.3 million at September 30, 2017 . 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 table below presents the valuation methodology and unobservable inputs for Level 3 assets measured at fair value on a non-recurring basis as of September 30, 2017 : (Dollars in thousands) Asset Fair Value Valuation Methodology Unobservable Inputs Range of Inputs Collateral dependent impaired loans and leases $ 15,955 Real Estate Appraisals Discount for appraisal type 0% - 20% Discount for costs to sell 0% - 15% OREO $ 2,587 Real Estate Appraisals Discount for appraisal type 0% - 20% Discount for costs to sell 8% Fair Value of Financial Instruments and Servicing Assets 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. 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 assumptions and establishes processes to challenge the pricing service's valuations 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. The fair values of all other borrowings are 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, subject to impairment testing. Mortgage servicing assets are considered to be recognized at fair value when they are recorded at below cost. Changes in fair value 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. The estimated fair values of selected financial instruments and servicing assets are as follows: At September 30, 2017 At December 31, 2016 (In thousands) Carrying Amount Fair Value Carrying Amount Fair Value Assets: Level 2 Held-to-maturity investment securities $ 4,497,311 $ 4,481,675 $ 4,160,658 $ 4,125,125 Transferred loans held for sale — — 7,317 7,444 Level 3 Loans and leases, net 17,244,618 17,155,002 16,832,268 16,678,106 Mortgage servicing assets 25,140 44,992 24,466 52,075 Alternative investments 10,296 12,539 11,034 13,189 Liabilities: Level 2 Deposit liabilities $ 18,636,744 $ 18,636,744 $ 17,279,049 $ 17,279,049 Time deposits 2,218,491 2,213,155 2,024,808 2,024,395 Securities sold under agreements to repurchase and other borrowings 902,902 905,249 949,526 955,660 FHLB advances (1) 1,507,681 1,512,203 2,842,908 2,825,101 Long-term debt (1) 225,704 235,686 225,514 225,514 (1) The following adjustments to the carrying amount are not included for determination of fair value, see Note 8: Borrowings : • FHLB advances - unamortized premiums on advances •

Retirement Benefit Plans

Retirement Benefit Plans	9 Months Ended
	Sep. 30, 2017
Retirement Benefits [Abstract]
Retirement Benefit Plans	Retirement Benefit Plans Defined benefit pension and other postretirement benefits The following table summarizes the components of net periodic benefit cost: Three months ended September 30, 2017 2016 (In thousands) Pension Plan SERP Other Benefits Pension Plan SERP Other Benefits Service cost $ 12 $ — $ — $ 11 $ — $ — Interest cost on benefit obligations 1,829 96 19 2,110 98 32 Expected return on plan assets (3,074 ) — — (3,067 ) — — Amortization of prior service cost — — — — — 4 Recognized net loss 1,466 136 (15 ) 1,666 106 8 Net periodic benefit cost $ 233 $ 232 $ 4 $ 720 $ 204 $ 44 Nine months ended September 30, 2017 2016 (In thousands) Pension Plan SERP Other Benefits Pension Plan SERP Other Benefits Service cost $ 37 $ — $ — $ 34 $ — $ — Interest cost on benefit obligations 5,486 281 69 6,331 292 94 Expected return on plan assets (9,222 ) — — (8,596 ) — — Amortization of prior service cost — — — — — 11 Recognized net loss 4,398 561 — 4,998 319 26 Net periodic benefit cost $ 699 $ 842 $ 69 $ 2,767 $ 611 $ 131

Share-Based Plans

Share-Based Plans	9 Months Ended
	Sep. 30, 2017
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 non-qualified stock options, incentive stock options, restricted stock, restricted stock units, 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 following table provides a summary of stock compensation expense recognized in the accompanying Condensed Consolidated Statements of Income: Three months ended September 30, Nine months ended September 30, (In thousands) 2017 2016 2017 2016 Stock options $ — $ — $ — $ 43 Restricted stock 3,007 2,944 9,050 8,515 Total stock compensation expense $ 3,007 $ 2,944 $ 9,050 $ 8,558 At September 30, 2017 there was $16.7 million of unrecognized stock compensation expense for restricted stock expected to be recognized over a weighted-average period of 2.0 years . The following table provides a summary of the stock compensation plans activity for the nine months ended September 30, 2017 : Restricted Stock Awards Outstanding Stock Options Outstanding Time-Based Performance-Based Number of Shares Weighted-Average Grant Date Fair Value Number of Units Weighted-Average Grant Date Fair Value Number of Shares Weighted-Average Grant Date Fair Value Number of Shares Weighted-Average Exercise Price Outstanding, at January 1, 2017 253,361 $ 32.24 2,158 $ 32.89 116,184 $ 33.62 1,072,974 $ 21.24 Granted 164,953 54.79 8,129 56.07 89,581 56.18 — — Exercised options — — — — — — 279,344 25.80 Vested restricted stock awards (1) 155,390 36.36 6,900 48.82 87,982 40.74 — — Forfeited 14,586 36.44 — — 6,276 42.72 — — Outstanding and exercisable, at September 30, 2017 248,338 $ 43.96 3,387 $ 56.07 111,507 $ 45.61 793,630 $ 19.63 (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 5 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 a 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 0 to 150% . The performance criteria for 50% of the shares granted in 2017 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 three 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. 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. All awarded options have vested. There were 735,785 non-qualified stock options and 57,845 incentive stock options outstanding at September 30, 2017

Segment Reporting

Segment Reporting	9 Months Ended
	Sep. 30, 2017
Segment Reporting [Abstract]
Segment Reporting	Segment Reporting Webster’s operations are organized into three reportable segments that represent its primary businesses - Commercial Banking, Community Banking and HSA Bank. 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 Funds Transfer Pricing. 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 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. Provision expense for certain elements of risk that are not deemed specifically attributable to a reportable segment, such as the provision for the consumer liquidating portfolio, is shown as part of the Corporate and Reconciling category. 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. Income tax expense is allocated to each reportable segment based on the consolidated effective income tax rate for the period shown. Segment Reporting Modifications The 2016 segment results have been adjusted for comparability to the 2017 segment presentation for the following changes. • To further strengthen Webster's ability to deliver the totality of its products and services to the owners and executives of commercial clients and other high net worth individuals, an organizational change was made during the second quarter of 2017. Effective April 1, 2017, the head of Private Banking reports directly to the head of Commercial Banking. The current organizational structure reflects how executive management responsibilities are assigned and reviewed. As a result of this change, the Private Banking and Commercial Banking operating segments are aggregated into one reportable segment, Commercial Banking. • In late 2007 Webster discontinued its indirect residential construction lending and its indirect home equity lending outside of its primary New England market area referred to as National Wholesale Lending. Webster placed these two portfolios into a liquidating loan portfolio included within the Corporate and Reconciling category. The balance of the home equity liquidating loan portfolio was $65.0 million at December 31, 2016 . As the remainder of this portfolio has been performing in the same manner as the continuing home equity portfolio, management has decided to combine the liquidating loan portfolio with the continuing home equity loan portfolio. The combined portfolio is included in the Community Banking reportable segment. The following table presents total assets for Webster's reportable segments and the Corporate and Reconciling category: Total Assets (In thousands) Commercial Banking Community Banking HSA Bank Corporate and Reconciling Consolidated Total At September 30, 2017 $ 9,428,676 $ 8,881,322 $ 76,090 $ 7,964,094 $ 26,350,182 At December 31, 2016 9,069,445 8,721,046 83,987 8,198,051 26,072,529 The following tables present the operating results, including all appropriate allocations, for Webster’s reportable segments and the Corporate and Reconciling category: Three months ended September 30, 2017 (In thousands) Commercial Banking Community Banking HSA Bank Corporate and Reconciling Consolidated Total Net interest income (expense) $ 81,925 $ 96,859 $ 26,713 $ (4,593 ) $ 200,904 Provision (benefit) for loan and lease losses 12,073 (1,923 ) — — 10,150 Net interest income (expense) after provision for loan and lease losses 69,852 98,782 26,713 (4,593 ) 190,754 Non-interest income 13,207 27,079 19,371 6,189 65,846 Non-interest expense 38,339 92,478 27,222 3,784 161,823 Income (loss) before income tax expense 44,720 33,383 18,862 (2,188 ) 94,777 Income tax expense (benefit) 14,363 10,605 6,006 (693 ) 30,281 Net income (loss) $ 30,357 $ 22,778 $ 12,856 $ (1,495 ) $ 64,496 Three months ended September 30, 2016 (In thousands) Commercial Banking Community Banking HSA Bank Corporate and Reconciling Consolidated Total Net interest income (expense) $ 74,265 $ 91,995 $ 20,560 $ (6,623 ) $ 180,197 Provision for loan and lease losses 7,876 6,374 — — 14,250 Net interest income (expense) after provision for loan and lease losses 66,389 85,621 20,560 (6,623 ) 165,947 Non-interest income 15,916 29,130 16,900 4,466 66,412 Non-interest expense 35,793 92,508 23,021 4,775 156,097 Income (loss) before income tax expense 46,512 22,243 14,439 (6,932 ) 76,262 Income tax expense (benefit) 14,957 7,122 4,624 (2,258 ) 24,445 Net income (loss) $ 31,555 $ 15,121 $ 9,815 $ (4,674 ) $ 51,817 Nine months ended September 30, 2017 (In thousands) Commercial Banking Community Banking HSA Bank Corporate and Reconciling Consolidated Total Net interest income (expense) $ 239,118 $ 286,351 $ 76,339 $ (10,453 ) $ 591,355 Provision for loan and lease losses 29,562 (1,662 ) — — 27,900 Net interest income (expense) after provision for loan and lease losses 209,556 288,013 76,339 (10,453 ) 563,455 Non-interest income 39,163 80,516 58,392 15,368 193,439 Non-interest expense 113,767 281,979 84,211 10,069 490,026 Income (loss) before income tax expense 134,952 86,550 50,520 (5,154 ) 266,868 Income tax expense (benefit) 41,125 26,374 15,395 (1,572 ) 81,322 Net income (loss) $ 93,827 $ 60,176 $ 35,125 $ (3,582 ) $ 185,546 Nine months ended September 30, 2016 (In thousands) Commercial Banking Community Banking HSA Bank Corporate and Reconciling Consolidated Total Net interest income (expense) $ 211,422 $ 274,186 $ 60,484 $ (12,838 ) $ 533,254 Provision for loan and lease losses 29,765 14,085 — — 43,850 Net interest income (expense) after provision for loan and lease losses 181,657 260,101 60,484 (12,838 ) 489,404 Non-interest income 41,819 83,248 54,969 13,825 193,861 Non-interest expense 103,336 276,045 71,966 9,973 461,320 Income (loss) before income tax expense 120,140 67,304 43,487 (8,986 ) 221,945 Income tax expense (benefit) 39,233 21,979 14,201 (2,935 ) 72,478 Net income (loss) $ 80,907 $ 45,325 $ 29,286 $ (6,051 ) $ 149,467

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2017
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies 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: (In thousands) At September 30, 2017 At December 31, 2016 Commitments to extend credit $ 5,043,151 $ 5,224,280 Standby letter of credit 159,485 128,985 Commercial letter of credit 42,007 46,497 Total credit-related financial instruments with off-balance sheet risk $ 5,244,643 $ 5,399,762 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 to which they relate. These commitments subject the Company to potential exposure in excess of the 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 Condensed Consolidated Balance Sheets. The following table provides a summary of activity in the reserve for unfunded credit commitments: Three months ended September 30, Nine months ended September 30, (In thousands) 2017 2016 2017 2016 Beginning balance $ 2,544 $ 2,319 $ 2,287 $ 2,119 Provision charged to expense — 172 257 372 Ending balance $ 2,544 $ 2,491 $ 2,544 $ 2,491 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 an accrual for litigation and claims when a loss contingency is considered probable and the related amount is reasonably estimable. This accrual is 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 accrual, Webster believes that at September 30, 2017

Summary of Significant Accoun26

Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2017
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. The accompanying unaudited Condensed Consolidated Financial Statements of the Company have been prepared in conformity with the instructions for Form 10-Q and Rule 10-01 of Regulation S-X. Accordingly, they do not include all the information and notes required by GAAP for complete financial statements and should be read in conjunction with the Company's Consolidated Financial Statements, and Notes thereto, for the year ended December 31, 2016 , included in the Company's Annual Report on Form 10-K filed with the SEC on March 1, 2017.
Reclassification	Certain prior period amounts have been reclassified to conform to the current year's presentation. These reclassifications had an immaterial effect on non-interest income, non-interest expense, net cash provided by operating activities, and net cash used for investing activities.
Derivatives, Reporting of Derivative Activity [Policy Text Block]	Centrally Cleared Derivatives Effective during the first quarter of 2016, the Company offset the variation margin pertaining to derivatives reported on a net basis, subject to a legally enforceable master netting arrangement, with the same counterparty against the net derivative position on the Company's balance sheets. The Chicago Mercantile Exchange has amended their rulebooks to legally characterize variation margin payments for over-the-counter derivatives that clear, as settlements rather than collateral, effective January 3, 2017.
New Accounting Pronouncements, Policy [Policy Text Block]	Accounting Standards Adopted during 2017 Effective January 1, 2017, the following new accounting guidance was adopted by the Company: ASU No. 2016-09, Compensation - Stock Compensation (Topic 718) - Improvements to Employee Share Based Payment Accounting The Update impacted the accounting for employee share-based payment transactions, including the income tax consequences, and classification on the statement of cash flows. The Update requires the Company to recognize the income tax effects of awards in the income statement on a prospective basis when the awards vest or are settled, compared to within additional paid-in capital. As a result, applicable excess tax benefits and tax deficiencies are recorded as an income tax benefit or expense, respectively. The Company elected to present the classification on the statement of cash flows on a prospective basis to better align this presentation with the income tax effects. The impact of the Update will vary from period to period based on the Company's stock price and the quantity of shares that vest or are settled within a given period. The Update also requires the Company to elect the accounting for forfeitures of share-based payments by either (i) recognizing forfeitures of awards as they occur or (ii) estimating the number of awards expected to be forfeited and adjusting the estimate when it is likely to change, as is currently required. The Company elected to account for forfeitures of share-based payments by estimating the number of awards expected to be forfeited and adjusting the estimate when it is likely to change, which is in accordance with the Company's previous accounting practices. The adoption of this accounting standard did not have a material impact on the Company's financial statements. ASU No. 2016-06, Derivatives and Hedging (Topic 815) - Contingent Put and Call Options in Debt Instruments. The Update clarifies the requirements for assessing whether contingent call (put) options that can accelerate the payment of principal on debt instruments are clearly and closely related to their debt hosts. The Update requires the assessment of embedded call (put) options solely in accordance with the four-step decision sequence. The Update clarified that companies are not required to assess whether the event triggering the ability to exercise the call/put option was also clearly and closely related. The adoption of this accounting standard did not have a material impact on the Company's financial statements, as the Company has not performed the additional step of assessing whether the event triggering the ability to exercise the call (put) option was clearly and closely related, which was deemed not required by the Update. 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. 2017-12, Derivatives and Hedging (Topic 815) - Targeted Improvements to Accounting for Hedging Activities. The purpose of the Update is to better align a company’s 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 Company is in the process of assessing all potential impacts of the standard. The Update is effective for the first quarter of 2019, early adoption is permitted. The Company is evaluating the potential to early adopt the Update. ASU No. 2017-08, Receivables - Nonrefundable Fees and Other Costs (Subtopic 310-20) - Premium Amortization on Purchased Callable Debt Securities. The Update is intended to enhance the accounting for the amortization of premiums for purchased callable debt securities. Specifically, 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. The Update is being issued in response to concerns from stakeholders that, current GAAP excludes certain callable debt securities from consideration of early repayment of principal even if the holder is certain that the call will be exercised. The Update, upon adoption, is expected to accelerate the Company’s recognition of premium amortization on debt securities held within the portfolio. The amendments in the Update will be applied on a modified retrospective basis through a cumulative-effect adjustment directly through retained earnings upon adoption. Management is in the process of evaluating the full impact of adopting the Update including, but not limited to the following: • Modifying system amortization requirements; • Evaluation of premiums associated with debt securities to determine the appropriate cumulative-effect adjustment; and • Establishing new accounting policies pertaining to premium amortization on purchased callable debt securities. The Update is effective for the first quarter of 2019, early adoption is permitted. The Company is evaluating the potential to early adopt the Update. 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 disaggregate the current-service-cost component from the other components of net benefit cost (the “other components”) and present it with other current compensation costs for related employees in the income statement and present the other components elsewhere in the income statement and outside of income from operations if that subtotal is presented. In addition, the Update requires entities to disclose the income statement lines that contain the other components if they are not presented on appropriately described separate lines. The new guidance will be applied on a retrospective basis. The Company intends to adopt the Update for the first quarter of 2018. The Company does not expect this guidance to have a material impact on its consolidated financial statements. ASU No. 2017-04, Intangibles - Goodwill and Other (Topic 350) - Simplifying the Test for Goodwill Impairment. The Update eliminates Step 2 from the goodwill impairment analysis. Step 2, requires the Company to perform procedures to determine the fair value at the impairment testing date of its assets and liabilities (including unrecognized assets and liabilities). Under current guidance, Step 2 testing would be performed only if Step 1 testing indicated the fair value of the reporting unit is below the reporting unit’s carrying amount. Once effective the Update will require the Company to record an impairment charge for the amount by which the carrying amount exceeds the reporting unit’s fair value, eliminating the Step 2 requirements. The Company intends to adopt the Update for the first quarter of 2020. Adoption is not anticipated to have a material impact on the Company's financial statements. ASU No. 2016-15, Statement of Cash Flows (Topic 230) - Classification of Certain Cash Receipts and Cash Payments. The Update addresses eight specific cash flow issues with the objective of reducing the existing diversity in practice. The Update addresses the following eight issues: 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 intends to adopt the Update for the first quarter of 2018. The Company does not expect this 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. Current GAAP requires an "incurred loss" methodology for recognizing credit losses that delays recognition until it is probable a loss has been incurred. Both financial institutions and users of their financial statements expressed concern that current GAAP restricts the ability to record credit losses that are expected, but do not yet meet the "probable" threshold. 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 is likely to result in a material increase to the Company's accounting for credit losses on financial instruments. The Company has established a project lead and identified a working group comprised of members from different disciplines including Credit, Finance and Information Technology. The Company is in the early stages of evaluation of the effect that this ASU will have on its financial statements and related disclosures, but has begun to develop a roadmap which includes a consideration of external resources that may be required, use of existing and new models, data availability and system solutions to facilitate implementation. The ASU will be effective for the Company as of the first quarter 2020. While we are currently unable to reasonably estimate the impact of adopting the Update, we expect the impact of adoption will be significantly influenced by the composition, characteristics and quality of our loan and securities portfolios as well as the economic conditions as of the adoption date. ASU No. 2016-02, Leases (Topic 842). The Update introduces a lessee model that brings most leases on the balance sheet. The Update also aligns certain of the underlying principles of the new lessor model with those in ASC 606 "Revenue from Contracts with Customers", the FASB’s new revenue recognition standard (e.g., evaluating how collectability should be considered and determining when profit can be recognized). Furthermore, the Update addresses other concerns including the elimination of the required use of bright-line tests for determining lease classification. Lessors are required to provide additional transparency into the exposure to the changes in value of their residual assets and how they manage that exposure. The Company intends to adopt the Update for the first quarter of 2019 using the modified retrospective method. The Company is in the early assessment stage and will continue to review the existing lease portfolio to evaluate the impact of the new accounting guidance on the financial statements. ASU No. 2016-01, Financial Instruments - Overall (Subtopic 825-10) - Recognition and Measurement of Financial Assets and Financial Liabilities. Equity investments not accounted for under the equity method or those that do not result in consolidation of the investee are to be measured at fair value with changes in the fair value recognized through net income. Entities are to present separately in other comprehensive income, the portion of the total change in the fair value of a liability resulting from a change in the instrument-specific credit risk when an election to measure the liability at fair value in accordance with the fair value option for financial instruments has been made. Also, the requirement to disclose the method(s) and significant assumptions used to estimate the fair value for financial instruments measured at amortized cost on the balance sheet has been eliminated. The Company intends to adopt the Update for the first quarter of 2018. Adoption is not anticipated to have a material impact on the Company's financial statements. ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606). Also, subsequent ASUs issued to clarify this Topic. The Update requires an entity to recognize the amount of revenue to which it expects to be entitled for the transfer of promised goods or services to customers. The Update excludes the Company's revenue associated with net interest income, and certain non-interest income lines items (loan and lease related fees, mortgage banking activities, increase in cash surrender value of life insurance policies, gain on sale of investment securities, net, impairment loss on securities recognized in earnings, and a majority of other income). As a result a substantial amount of the Company's revenue will not be affected. The Company's deposit service fees, wealth and investment services, and certain other non-interest income items are within the scope of the Update. The Company's evaluation of the impacted revenue streams and associated customer contracts is near completion. While the assessment is not complete, the timing of the Company's revenue recognition is not expected to materially change. The disclosure objective of the Update is to provide users of the financial statement with sufficient information to understand the nature, amount, timing and uncertainty of revenue, certain costs, and cash flows arising from contracts with customers. The Company expects to provide expanded qualitative disclosure pertaining to significant judgments, accounting policy elections and the nature, timing, and uncertainty of revenue arising from contracts with customers. Further the Company expects to provide expanded quantitative disclosure pertaining to the disaggregation of revenue arising from contracts with customers. The Company continues to assess the impact of the changes in disclosure required by guidance.

Investment Securities (Tables)

Investment Securities (Tables)	9 Months Ended
	Sep. 30, 2017
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 September 30, 2017 At December 31, 2016 (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 $ 3,596 $ — $ — $ 3,596 $ 734 $ — $ — $ 734 Agency CMO 332,341 2,573 (3,116 ) 331,798 419,865 3,344 (3,503 ) 419,706 Agency MBS 923,819 3,214 (14,056 ) 912,977 969,460 4,398 (19,509 ) 954,349 Agency CMBS 599,165 — (14,205 ) 584,960 587,776 63 (14,567 ) 573,272 CMBS 402,015 1,539 (121 ) 403,433 473,974 4,093 (702 ) 477,365 CLO 273,172 1,572 (161 ) 274,583 425,083 2,826 (519 ) 427,390 Trust preferred 30,463 676 (202 ) 30,937 30,381 — (1,748 ) 28,633 Corporate debt 48,334 674 (130 ) 48,878 108,490 1,502 (350 ) 109,642 Available-for-sale $ 2,612,905 $ 10,248 $ (31,991 ) $ 2,591,162 $ 3,015,763 $ 16,226 $ (40,898 ) $ 2,991,091 Held-to-maturity: Agency CMO $ 276,367 $ 1,138 $ (3,030 ) $ 274,475 $ 339,455 $ 1,977 $ (3,824 ) $ 337,608 Agency MBS 2,549,500 24,275 (30,012 ) 2,543,763 2,317,449 26,388 (41,768 ) 2,302,069 Agency CMBS 708,229 280 (3,549 ) 704,960 547,726 694 (1,348 ) 547,072 Municipal bonds and notes 705,411 5,213 (13,150 ) 697,474 655,813 4,389 (25,749 ) 634,453 CMBS 257,361 3,394 (197 ) 260,558 298,538 4,107 (411 ) 302,234 Private Label MBS 443 2 — 445 1,677 12 — 1,689 Held-to-maturity $ 4,497,311 $ 34,302 $ (49,938 ) $ 4,481,675 $ 4,160,658 $ 37,567 $ (73,100 ) $ 4,125,125
Summary of Changes in OTTI	The following table presents the changes in OTTI: Three months ended September 30, Nine months ended September 30, (In thousands) 2017 2016 2017 2016 Beginning balance $ 3,231 $ 3,437 $ 3,243 $ 3,288 Reduction for investment securities sold or called (1,028 ) (30 ) (1,166 ) (30 ) Additions for OTTI not previously recognized in earnings — — 126 149 Ending balance $ 2,203 $ 3,407 $ 2,203 $ 3,407
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 September 30, 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 $ 75,042 $ (1,002 ) $ 70,167 $ (2,114 ) 16 $ 145,209 $ (3,116 ) Agency MBS 464,031 (5,169 ) 303,770 (8,887 ) 104 767,801 (14,056 ) Agency CMBS 306,025 (6,240 ) 278,935 (7,965 ) 34 584,960 (14,205 ) CMBS 39,775 (121 ) — — 5 39,775 (121 ) CLO 82,989 (161 ) — — 5 82,989 (161 ) Trust preferred 12,570 (97 ) 4,574 (105 ) 3 17,144 (202 ) Corporate debt 5,797 (87 ) 1,825 (43 ) 2 7,622 (130 ) Available-for-sale in an unrealized loss position $ 986,229 $ (12,877 ) $ 659,271 $ (19,114 ) 169 $ 1,645,500 $ (31,991 ) Held-to-maturity: Agency CMO $ 82,839 $ (880 ) $ 83,103 $ (2,150 ) 19 $ 165,942 $ (3,030 ) Agency MBS 870,376 (7,948 ) 775,331 (22,064 ) 157 1,645,707 (30,012 ) Agency CMBS 570,781 (3,504 ) 4,730 (45 ) 45 575,511 (3,549 ) Municipal bonds and notes 123,965 (1,745 ) 226,545 (11,405 ) 140 350,510 (13,150 ) CMBS 40,150 (197 ) 250 — 5 40,400 (197 ) Held-to-maturity in an unrealized loss position $ 1,688,111 $ (14,274 ) $ 1,089,959 $ (35,664 ) 366 $ 2,778,070 $ (49,938 ) At December 31, 2016 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 $ 107,853 $ (2,168 ) $ 67,351 $ (1,335 ) 15 $ 175,204 $ (3,503 ) Agency MBS 512,075 (10,503 ) 252,779 (9,006 ) 97 764,854 (19,509 ) Agency CMBS 554,246 (14,567 ) — — 32 554,246 (14,567 ) CMBS 12,427 (24 ) 63,930 (678 ) 12 76,357 (702 ) CLO 49,946 (54 ) 50,237 (465 ) 5 100,183 (519 ) Trust preferred — — 28,633 (1,748 ) 5 28,633 (1,748 ) Corporate debt — — 7,384 (350 ) 2 7,384 (350 ) Available-for-sale in an unrealized loss position $ 1,236,547 $ (27,316 ) $ 470,314 $ (13,582 ) 168 $ 1,706,861 $ (40,898 ) Held-to-maturity: Agency CMO $ 163,439 $ (3,339 ) $ 17,254 $ (485 ) 16 $ 180,693 $ (3,824 ) Agency MBS 1,394,623 (32,942 ) 273,779 (8,826 ) 150 1,668,402 (41,768 ) Agency CMBS 347,725 (1,348 ) — — 25 347,725 (1,348 ) Municipal bonds and notes 384,795 (25,745 ) 1,192 (4 ) 196 385,987 (25,749 ) CMBS 60,768 (411 ) — — 8 60,768 (411 ) Held-to-maturity in an unrealized loss position $ 2,351,350 $ (63,785 ) $ 292,225 $ (9,315 ) 395 $ 2,643,575 $ (73,100 )
Summary of Debt Securities by Contractual Maturity	The amortized cost and fair value of debt securities by contractual maturity are set forth below: At September 30, 2017 Available-for-Sale Held-to-Maturity (In thousands) Amortized Cost Fair Value Amortized Cost Fair Value Due in one year or less $ 18,668 $ 18,714 $ 40,146 $ 40,753 Due after one year through five years 40,246 40,748 13,410 13,684 Due after five through ten years 381,547 383,721 38,323 39,102 Due after ten years 2,172,444 2,147,979 4,405,432 4,388,136 Total debt securities $ 2,612,905 $ 2,591,162 $ 4,497,311 $ 4,481,675

Loans and Leases (Tables)

Loans and Leases (Tables)	9 Months Ended
	Sep. 30, 2017
Loans and Leases Receivable Disclosure [Abstract]
Schedule of Accounts, Notes, Loans and Financing Receivable	The following table summarizes loans and leases: (In thousands) At September 30, At December 31, 2016 Residential $ 4,499,441 $ 4,254,682 Consumer 2,566,983 2,684,500 Commercial 5,348,303 4,940,931 Commercial Real Estate 4,464,917 4,510,846 Equipment Financing 566,777 635,629 Loans and leases (1) (2) $ 17,446,421 $ 17,026,588 (1) Loans and leases include net deferred fees and net premiums/discounts of $20.8 million and $17.3 million at September 30, 2017 and December 31, 2016 , respectively. (2) At September 30, 2017 , the Company had pledged $6.7 billion
Past Due Financing Receivables	The following tables summarize the aging of loans and leases: At September 30, 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 Residential $ 8,069 $ 3,654 $ — $ 45,676 $ 57,399 $ 4,442,042 $ 4,499,441 Consumer: Home equity 7,613 4,685 — 37,105 49,403 2,269,468 2,318,871 Other consumer 2,224 1,454 — 1,859 5,537 242,575 248,112 Commercial: Commercial non-mortgage 1,948 364 934 58,915 62,161 4,402,543 4,464,704 Asset-based — — — 8,558 8,558 875,041 883,599 Commercial real estate: Commercial real estate 1,347 444 — 10,603 12,394 4,161,572 4,173,966 Commercial construction — — — 477 477 290,474 290,951 Equipment financing 818 49 — 570 1,437 565,340 566,777 Total $ 22,019 $ 10,650 $ 934 $ 163,763 $ 197,366 $ 17,249,055 $ 17,446,421 At December 31, 2016 (In thousands) 30-59 Days 60-89 Days Past Due and Accruing 90 or More Days Past Due Non-accrual Total Past Due and Non-accrual Current Total Loans Residential $ 8,631 $ 2,609 $ — $ 47,279 $ 58,519 $ 4,196,163 $ 4,254,682 Consumer: Home equity 8,831 5,782 — 35,926 50,539 2,359,354 2,409,893 Other consumer 2,233 1,485 — 1,663 5,381 269,226 274,607 Commercial: Commercial non-mortgage 1,382 577 749 38,190 40,898 4,094,727 4,135,625 Asset-based — — — — — 805,306 805,306 Commercial real estate: Commercial real estate 6,357 1,816 — 9,871 18,044 4,117,742 4,135,786 Commercial construction — — — 662 662 374,398 375,060 Equipment financing 903 693 — 225 1,821 633,808 635,629 Total $ 28,337 $ 12,962 $ 749 $ 133,816 $ 175,864 $ 16,850,724 $ 17,026,588
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 three months ended September 30, 2017 Residential Consumer Commercial Commercial Real Estate Equipment Financing Total ALLL: Balance, beginning of period $ 18,427 $ 42,488 $ 79,964 $ 52,402 $ 6,297 $ 199,578 (Benefit) provision charged to expense (348 ) (41 ) 12,166 (2,129 ) 502 10,150 Charge-offs (585 ) (6,197 ) (3,002 ) (749 ) (121 ) (10,654 ) Recoveries 280 1,894 466 10 79 2,729 Balance, end of period $ 17,774 $ 38,144 $ 89,594 $ 49,534 $ 6,757 $ 201,803 At or for the three months ended September 30, 2016 (In thousands) Residential Consumer Commercial Commercial Real Estate Equipment Financing Total ALLL: Balance, beginning of period $ 24,413 $ 42,956 $ 73,822 $ 33,622 $ 5,615 $ 180,428 Provision charged to expense 1,076 4,985 4,351 2,953 885 14,250 Charge-offs (1,304 ) (5,259 ) (2,561 ) — (300 ) (9,424 ) Recoveries 554 1,313 370 194 240 2,671 Balance, end of period $ 24,739 $ 43,995 $ 75,982 $ 36,769 $ 6,440 $ 187,925 At or for the nine months ended September 30, 2017 (In thousands) Residential Consumer Commercial Commercial Real Estate Equipment Financing Total ALLL: Balance, beginning of period $ 23,226 $ 45,233 $ 71,905 $ 47,477 $ 6,479 $ 194,320 (Benefit) provision charged to expense (4,436 ) 6,847 21,905 2,987 597 27,900 Charge-offs (1,940 ) (18,273 ) (5,321 ) (951 ) (425 ) (26,910 ) Recoveries 924 4,337 1,105 21 106 6,493 Balance, end of period $ 17,774 $ 38,144 $ 89,594 $ 49,534 $ 6,757 $ 201,803 Individually evaluated for impairment $ 4,925 $ 1,689 $ 10,844 $ 290 $ 38 $ 17,786 Collectively evaluated for impairment $ 12,849 $ 36,455 $ 78,750 $ 49,244 $ 6,719 $ 184,017 Loan and lease balances: Individually evaluated for impairment $ 116,706 $ 46,224 $ 85,385 $ 18,199 $ 3,642 $ 270,156 Collectively evaluated for impairment 4,382,735 2,520,759 5,262,918 4,446,718 563,135 17,176,265 Loans and leases $ 4,499,441 $ 2,566,983 $ 5,348,303 $ 4,464,917 $ 566,777 $ 17,446,421 At or for the nine months ended September 30, 2016 (In thousands) Residential Consumer Commercial Commercial Real Estate Equipment Financing Total ALLL: Balance, beginning of period $ 25,876 $ 42,052 $ 66,686 $ 34,889 $ 5,487 $ 174,990 Provision charged to expense 991 12,458 25,447 3,921 1,033 43,850 Charge-offs (3,536 ) (14,236 ) (17,294 ) (2,521 ) (521 ) (38,108 ) Recoveries 1,408 3,721 1,143 480 441 7,193 Balance, end of period $ 24,739 $ 43,995 $ 75,982 $ 36,769 $ 6,440 $ 187,925 Individually evaluated for impairment $ 9,443 $ 3,005 $ 6,579 $ 467 $ 9 $ 19,503 Collectively evaluated for impairment $ 15,296 $ 40,990 $ 69,403 $ 36,302 $ 6,431 $ 168,422 Loan and lease balances: Individually evaluated for impairment $ 122,020 $ 46,208 $ 58,197 $ 24,423 $ 6,863 $ 257,711 Collectively evaluated for impairment 4,112,027 2,661,135 4,721,605 4,256,090 614,833 16,365,690 Loans and leases $ 4,234,047 $ 2,707,343 $ 4,779,802 $ 4,280,513 $ 621,696 $ 16,623,401
Impaired Loans	The following tables summarize impaired loans and leases: At September 30, 2017 (In thousands) Unpaid Principal Balance Total Recorded Investment No Allowance Recorded Investment With Allowance Related Valuation Allowance Residential $ 127,986 $ 116,706 $ 27,961 $ 88,745 $ 4,925 Consumer - home equity 51,496 46,225 21,833 24,392 1,689 Commercial : Commercial non-mortgage 88,221 76,827 28,124 48,703 10,844 Asset-based 8,558 8,558 8,558 — — Commercial real estate: Commercial real estate 19,026 17,725 12,894 4,831 271 Commercial construction 580 474 — 474 19 Equipment financing 3,721 3,642 3,004 638 38 Total $ 299,588 $ 270,157 $ 102,374 $ 167,783 $ 17,786 At December 31, 2016 (In thousands) Unpaid Principal Balance Total Recorded Investment No Allowance Recorded Investment With Allowance Related Valuation Allowance Residential $ 131,468 $ 119,424 $ 21,068 $ 98,356 $ 8,090 Consumer - home equity 52,432 45,719 22,746 22,973 2,903 Commercial : Commercial non-mortgage 57,732 53,037 26,006 27,031 7,422 Asset-based — — — — — Commercial real estate: Commercial real estate 24,146 23,568 19,591 3,977 169 Commercial construction 1,188 1,187 1,187 — — Equipment financing 6,398 6,420 6,197 223 9 Total $ 273,364 $ 249,355 $ 96,795 $ 152,560 $ 18,593 The following table summarizes the average recorded investment and interest income recognized for impaired loans and leases: Three months ended September 30, Nine months ended September 30, 2017 2016 2017 2016 (In thousands) Average Recorded Investment Accrued Interest Income Cash Basis Interest Income Average Accrued Cash Basis Interest Income Average Recorded Investment Accrued Cash Basis Interest Income Average Recorded Investment Accrued Cash Basis Interest Income Residential $ 118,841 $ 1,027 $ 285 $ 124,993 $ 1,070 $ 304 $ 118,065 $ 3,133 $ 986 $ 128,234 $ 3,309 $ 918 Consumer - home equity 46,753 341 246 46,892 336 238 45,972 998 808 47,317 1,029 754 Commercial Commercial Non-Mortgage 81,816 249 — 58,874 352 — 64,932 704 — 57,389 1,299 — Asset based 4,279 — — — — — 4,279 — — — — Commercial real estate: Commercial real estate 20,249 96 — 23,930 77 — 20,647 329 — 26,689 374 — Commercial construction 828 — — 4,386 12 — 831 12 — 5,171 81 — Equipment financing 4,895 30 — 3,642 107 — 5,031 168 — 3,642 109 — Total $ 277,661 $ 1,743 $ 531 $ 262,717 $ 1,954 $ 542 $ 259,757 $ 5,344 $ 1,794 $ 268,442 $ 6,201 $ 1,672
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 (In thousands) At September 30, At December 31, At September 30, At December 31, At September 30, At December 31, (1) - (6) Pass $ 5,037,439 $ 4,655,007 $ 4,266,658 $ 4,357,458 $ 548,298 $ 618,084 (7) Special Mention 108,828 56,240 85,926 69,023 3,557 1,324 (8) Substandard 192,161 226,603 112,333 84,365 14,922 16,221 (9) Doubtful 9,875 3,081 — — — — Total $ 5,348,303 $ 4,940,931 $ 4,464,917 $ 4,510,846 $ 566,777 $ 635,629
Troubled Debt Restructurings on Financing Receivables	Troubled Debt Restructurings The following table summarizes information for TDRs: (Dollars in thousands) At September 30, At December 31, 2016 Accrual status $ 135,774 $ 147,809 Non-accrual status 82,576 75,719 Total recorded investment of TDRs $ 218,350 $ 223,528 Specific reserves for TDRs included in the balance of ALLL $ 11,837 $ 14,583 Additional funds committed to borrowers in TDR status 3,944 459 For the portion of TDRs deemed to be uncollectible, Webster charged off $0.4 million and $3.0 million for the three months ended September 30, 2017 and 2016 , respectively, and $3.0 million , and $17.9 million for the nine months ended September 30, 2017 and 2016 , respectively. The following table provides information on the type of concession for loans and leases modified as TDRs: Three months ended September 30, Nine months ended September 30, 2017 2016 2017 2016 Number of Post- (1) Number of Post- (1) Number of Post- (1) Number of Post- (1) (Dollars in thousands) Residential: Extended Maturity — $ — 4 $ 967 9 $ 1,390 11 $ 1,969 Adjusted Interest Rate — — 1 292 2 335 2 528 Maturity/Rate Combined 4 570 3 290 9 1,416 10 1,185 Other (2) 6 1,357 3 299 32 5,471 18 3,190 Consumer - home equity Extended Maturity 2 158 2 89 8 822 9 381 Adjusted Interest Rate 1 247 — — 1 247 — — Maturity/Rate Combined 2 399 3 264 13 3,212 11 923 Other (2) 12 839 8 270 55 3,733 37 1,447 Commercial non - mortgage Extended Maturity — — 2 213 8 813 11 14,862 Maturity/Rate Combined 8 299 — — 13 9,153 2 648 Other (2) — — 4 1,265 1 4 11 1,639 Commercial real estate: Extended Maturity — — 1 109 — — 1 109 Maturity/Rate Combined — — 1 291 — — 2 335 Other (2) — — — — — — 1 509 Equipment Financing Extended Maturity — — 6 6,638 — — 7 6,642 Total TDRs 35 $ 3,869 38 $ 10,987 151 $ 26,596 133 $ 34,367 (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, or other concessions. Loans and leases modified as TDRs within the previous 12 months and for which there was a payment default, consisted of one residential loan with a recorded investment of $248 thousand for both the three and nine months ended September 30, 2017. There were no such loans and leases for both the three and nine months ended September 30, 2016. The recorded investment of TDRs in commercial, commercial real estate, and equipment financing segregated by risk rating exposure is as follows: (In thousands) At September 30, 2017 At December 31, 2016 (1) - (6) Pass $ 8,902 $ 10,210 (7) Special Mention 360 7 (8) Substandard 46,157 45,509 (9) Doubtful — 2,738 Total $ 55,419 $ 58,464

Transfers of Financial Assets (

Transfers of Financial Assets (Tables)	9 Months Ended
	Sep. 30, 2017
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: Three months ended September 30, Nine months ended September 30, (In thousands) 2017 2016 2017 2016 Beginning balance $ 843 $ 992 $ 790 $ 1,192 Provision (benefit) charged to expense 25 37 78 (64 ) Repurchased loans and settlements charged off (18 ) — (18 ) (99 ) Ending balance $ 850 $ 1,029 $ 850 $ 1,029 Three months ended September 30, Nine months ended September 30, (In thousands) 2017 2016 2017 2016 Beginning balance $ 2,544 $ 2,319 $ 2,287 $ 2,119 Provision charged to expense — 172 257 372 Ending balance $ 2,544 $ 2,491 $ 2,544 $ 2,491
Transfer of Financial Assets Accounted for as Sales [Table Text Block]	Three months ended September 30, Nine months ended September 30, (In thousands) 2017 2016 2017 2016 Residential mortgage loans held for sale: Proceeds from sale $ 88,691 $ 128,268 $ 262,029 $ 298,840 Loans sold with servicing rights retained 79,690 115,822 239,357 273,827 Net gain on sale 1,979 3,324 4,356 6,749 Ancillary fees 682 1,046 2,091 2,485 Fair value option adjustment (240 ) (48 ) 1,591 2,101
Servicing Asset at Amortized Cost [Table Text Block]	The following table presents the changes in carrying value for mortgage servicing assets: Three months ended September 30, Nine months ended September 30, (In thousands) 2017 2016 2017 2016 Beginning balance $ 24,708 $ 21,946 $ 24,466 $ 20,698 Additions 2,576 3,338 7,063 8,198 Amortization (2,144 ) (1,900 ) (6,389 ) (5,512 ) Ending balance $ 25,140 $ 23,384 $ 25,140 $ 23,384

Goodwill and Other Intangible30

Goodwill and Other Intangible Assets (Tables)	9 Months Ended
	Sep. 30, 2017
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 September 30, 2017 At December 31, 2016 (In thousands) Gross Carrying Amount Accumulated Amortization Net Carrying Amount Gross Carrying Amount Accumulated Amortization Net Carrying Amount Other intangible assets: HSA Bank CDI $ 22,000 $ (8,036 ) $ 13,964 $ 22,000 $ (6,162 ) $ 15,838 HSA Bank Customer relationships 21,000 (4,375 ) 16,625 21,000 (3,164 ) 17,836 Total other intangible assets $ 43,000 $ (12,411 ) $ 30,589 $ 43,000 $ (9,326 ) $ 33,674 Goodwill: Community Banking $ 516,560 $ 516,560 HSA Bank 21,813 21,813 Total goodwill $ 538,373 $ 538,373
Schedule Of Expected Amortization Expense, Next Four Years	As of September 30, 2017 , the remaining estimated aggregate future amortization expense for intangible assets is as follows: (In thousands) Remainder of 2017 $ 978 2018 3,847 2019 3,847 2020 3,847 2021 3,847 Thereafter 14,223

Deposits (Tables)

Deposits (Tables)	9 Months Ended
	Sep. 30, 2017
Banking and Thrift [Abstract]
Deposit Liabilities, Type [Table Text Block]	A summary of deposits by type follows: (In thousands) At September 30, At December 31, Non-interest-bearing: Demand $ 4,138,206 $ 4,021,061 Interest-bearing: Checking 2,581,266 2,528,274 Health savings accounts 4,891,024 4,362,503 Money market 2,598,187 2,047,121 Savings 4,428,061 4,320,090 Time deposits 2,218,491 2,024,808 Total interest-bearing 16,717,029 15,282,796 Total deposits $ 20,855,235 $ 19,303,857 Time deposits and interest-bearing checking, included in above balances, obtained through brokers $ 913,042 $ 848,618 Time deposits, included in above balance, that meet or exceed the FDIC limit 613,012 490,721 Deposit overdrafts reclassified as loan balances 2,494 1,885
Time Deposit Maturities [Table Text Block]	The scheduled maturities of time deposits are as follows: (In thousands) At September 30, Remainder of 2017 $ 285,203 2018 952,745 2019 607,952 2020 225,159 2021 107,921 Thereafter 39,511 Total time deposits $ 2,218,491

Borrowings (Tables)

Borrowings (Tables)	9 Months Ended
	Sep. 30, 2017
Debt Disclosure [Abstract]
Schedule of Repurchase Agreements	The following table summarizes securities sold under agreements to repurchase and other borrowings: At September 30, At December 31, (In thousands) Amount Rate Amount Rate Securities sold under agreements to repurchase: Original maturity of one year or less $ 335,902 0.18 % $ 340,526 0.16 % Original maturity of greater than one year, non-callable 400,000 3.04 400,000 3.09 Total securities sold under agreements to repurchase 735,902 1.73 740,526 1.82 Fed funds purchased 167,000 1.12 209,000 0.46 Securities sold under agreements to repurchase and other borrowings $ 902,902 1.62 % $ 949,526 1.53 %
Federal Home Loan Bank, Advances	The following table provides information for FHLB advances: At September 30, At December 31, (Dollars in thousands) Amount Weighted- Average Contractual Coupon Rate Amount Weighted- Average Contractual Coupon Rate Maturing within 1 year $ 880,500 1.28 % $ 2,130,500 0.71 % After 1 but within 2 years 133,731 1.34 200,000 1.36 After 2 but within 3 years 259,295 1.79 128,026 1.73 After 3 but within 4 years 75,000 1.51 175,000 1.77 After 4 but within 5 years 150,061 2.23 200,000 1.81 After 5 years 9,091 2.61 9,370 2.59 1,507,678 1.49 % 2,842,896 0.95 % Premiums on advances 3 12 Federal Home Loan Bank advances $ 1,507,681 $ 2,842,908 Aggregate carrying value of assets pledged as collateral $ 6,388,102 $ 5,967,318 Remaining borrowing capacity 2,668,964 1,192,758
Schedule of Long-term Debt Instruments	The following table summarizes long-term debt: (Dollars in thousands) At September 30, At December 31, 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 (756 ) (845 ) Debt issuance cost on senior fixed-rate notes (860 ) (961 ) Long-term debt $ 225,704 $ 225,514 (1) The interest rate on Webster Statutory Trust I floating-rate notes, which varies quarterly based on 3-month LIBOR plus 2.95% , was 4.27% at September 30, 2017 and 3.94% at December 31, 2016

Accumulated Other Comprehensi33

Accumulated Other Comprehensive Loss, Net of Tax (Tables)	9 Months Ended
	Sep. 30, 2017
Equity [Abstract]
Schedule of Changes in Accumulated Other Comprehensive Loss by Component	The following tables summarize the changes in AOCL by component: Three months ended September 30, 2017 Nine months ended September 30, 2017 (In thousands) Securities Available For Sale and Transferred Derivative Instruments Defined Benefit Pension and Other Postretirement Benefit Plans Total Securities Available For Sale and Transferred Derivative Instruments Defined Benefit Pension and Other Postretirement Benefit Plans Total Beginning balance $ (14,501 ) $ (15,258 ) $ (42,323 ) $ (72,082 ) $ (15,476 ) $ (17,068 ) $ (44,449 ) $ (76,993 ) OCI/OCL before reclassifications 872 (34 ) — 838 1,847 (445 ) — 1,402 Amounts reclassified from AOCL — 1,145 1,001 2,146 — 3,366 3,127 6,493 Net current-period OCI/OCL 872 1,111 1,001 2,984 1,847 2,921 3,127 7,895 Ending balance $ (13,629 ) $ (14,147 ) $ (41,322 ) $ (69,098 ) $ (13,629 ) $ (14,147 ) $ (41,322 ) $ (69,098 ) Three months ended September 30, 2016 Nine months ended September 30, 2016 (In thousands) Securities Available For Sale and Transferred Derivative Instruments Defined Benefit Pension and Other Postretirement Benefit Plans Total Securities Available For Sale and Transferred Derivative Instruments Defined Benefit Pension and Other Postretirement Benefit Plans Total Beginning balance $ 12,363 $ (23,406 ) $ (46,468 ) $ (57,511 ) $ (6,407 ) $ (22,980 ) $ (48,719 ) $ (78,106 ) OCI/OCL before reclassifications 1,218 794 — 2,012 20,156 (2,416 ) — 17,740 Amounts reclassified from AOCL — 1,221 1,125 2,346 (168 ) 4,005 3,376 7,213 Net current-period OCI/OCL 1,218 2,015 1,125 4,358 19,988 1,589 3,376 24,953 Ending balance $ 13,581 $ (21,391 ) $ (45,343 ) $ (53,153 ) $ 13,581 $ (21,391 ) $ (45,343 ) $ (53,153 )
Schedule of Accumulated Other Comprehensive Loss	The following tables provide information for the items reclassified from AOCL: (In thousands) Three months ended September 30, Nine months ended September 30, Associated Line Item in the Condensed Consolidated Statements of Income AOCL Components 2017 2016 2017 2016 Securities available-for-sale and transferred: Unrealized gains (losses) on investment securities $ — $ — $ — $ 414 Gain on sale of investment securities, net Unrealized gains (losses) on investment securities — — — (149 ) Impairment loss recognized in earnings Total before tax — — — 265 Tax benefit (expense) — — — (97 ) Income tax expense Net of tax $ — $ — $ — $ 168 Derivative instruments: Cash flow hedges $ (1,810 ) $ (1,925 ) $ (5,316 ) $ (6,314 ) Total interest expense Tax benefit 665 704 1,950 2,309 Income tax expense Net of tax $ (1,145 ) $ (1,221 ) $ (3,366 ) $ (4,005 ) Defined benefit pension and other postretirement benefit plans: Amortization of net loss $ (1,587 ) $ (1,780 ) $ (4,959 ) $ (5,343 ) (1) Prior service costs — (4 ) — (11 ) (1) Total before tax (1,587 ) (1,784 ) (4,959 ) (5,354 ) Tax benefit 586 659 1,832 1,978 Income tax expense Net of tax $ (1,001 ) $ (1,125 ) $ (3,127 ) $ (3,376 )

Regulatory Matters (Tables)

Regulatory Matters (Tables)	9 Months Ended
	Sep. 30, 2017
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: At September 30, 2017 Actual Minimum Requirement Well Capitalized (Dollars in thousands) Amount Ratio Amount Ratio Amount Ratio Webster Financial Corporation CET1 risk-based capital $ 2,031,955 10.99 % $ 832,149 4.5 % $ 1,201,993 6.5 % Total risk-based capital 2,436,332 13.17 1,479,376 8.0 1,849,220 10.0 Tier 1 risk-based capital 2,154,665 11.65 1,109,532 6.0 1,479,376 8.0 Tier 1 leverage capital 2,154,665 8.36 1,030,973 4.0 1,288,717 5.0 Webster Bank CET1 risk-based capital $ 2,061,764 11.16 % $ 831,319 4.5 % $ 1,200,794 6.5 % Total risk-based capital 2,266,110 12.27 1,477,900 8.0 1,847,376 10.0 Tier 1 risk-based capital 2,061,764 11.16 1,108,425 6.0 1,477,900 8.0 Tier 1 leverage capital 2,061,764 8.00 1,030,260 4.0 1,287,825 5.0 At December 31, 2016 Actual Minimum Requirement Well Capitalized (Dollars in thousands) Amount Ratio Amount Ratio Amount Ratio Webster Financial Corporation CET1 risk-based capital $ 1,932,171 10.52 % $ 826,504 4.5 % $ 1,193,840 6.5 % Total risk-based capital 2,328,808 12.68 1,469,341 8.0 1,836,677 10.0 Tier 1 risk-based capital 2,054,881 11.19 1,102,006 6.0 1,469,341 8.0 Tier 1 leverage capital 2,054,881 8.13 1,010,857 4.0 1,263,571 5.0 Webster Bank CET1 risk-based capital $ 1,945,332 10.61 % $ 825,228 4.5 % $ 1,191,995 6.5 % Total risk-based capital 2,141,939 11.68 1,467,071 8.0 1,833,839 10.0 Tier 1 risk-based capital 1,945,332 10.61 1,100,304 6.0 1,467,071 8.0 Tier 1 leverage capital 1,945,332 7.70 1,010,005 4.0 1,262,507 5.0

Earnings Per Common Share (Tabl

Earnings Per Common Share (Tables)	9 Months Ended
	Sep. 30, 2017
Earnings Per Share [Abstract]
Earnings Per Share Basic And Diluted	Reconciliation of the calculation of basic and diluted earnings per common share follows: Three months ended September 30, Nine months ended September 30, (In thousands, except per share data) 2017 2016 2017 2016 Earnings for basic and diluted earnings per common share: Net income $ 64,496 $ 51,817 $ 185,546 $ 149,467 Less: Preferred stock dividends 2,024 2,024 6,072 6,072 Net income available to common shareholders 62,472 49,793 179,474 143,395 Less: Earnings applicable to participating securities 46 159 212 468 Earnings applicable to common shareholders $ 62,426 $ 49,634 $ 179,262 $ 142,927 Shares: Weighted-average common shares outstanding - basic 92,125 91,365 92,003 91,298 Effect of dilutive securities: Stock options and restricted stock 372 465 403 452 Warrants 6 27 6 26 Weighted-average common shares outstanding - diluted 92,503 91,857 92,412 91,776 Earnings per common share: Basic $ 0.68 $ 0.54 $ 1.95 $ 1.57 Diluted 0.67 0.54 1.94 1.56
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: Three months ended September 30, Nine months ended September 30, (In thousands) 2017 2016 2017 2016 Stock options (shares with exercise price greater than market price) — 172 — 172 Restricted stock (due to performance conditions on non-participating shares) 80 — 61 161

Derivative Financial Instrume36

Derivative Financial Instruments (Tables)	9 Months Ended
	Sep. 30, 2017
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 September 30, 2017 At December 31, 2016 Asset Derivatives Liability Derivatives Asset Derivatives Liability Derivatives (In thousands) Notional Fair Notional Fair Notional Fair Notional Fair Designated as hedging instruments: Positions subject to a master netting agreement (1) Interest rate derivatives $ 225,000 $ 1,972 $ 100,000 $ 195 $ 225,000 $ 3,270 $ 100,000 $ 792 Not designated as hedging instruments: Positions subject to a master netting agreement (1) Interest rate derivatives 2,270,444 4,225 1,125,953 3,224 1,943,485 32,226 1,242,937 24,388 Other 8,595 260 22,161 419 10,634 231 14,265 120 Positions not subject to a master netting agreement Interest rate derivatives 1,738,527 35,065 1,652,004 15,764 1,734,679 38,668 1,451,762 19,001 RPAs 94,103 112 99,538 136 86,037 139 87,273 166 Mortgage banking derivatives (2) 42,290 614 60,698 128 103,440 3,084 59,895 711 Other 262 2 1,777 157 1,438 19 181 11 Total not designated as hedging instruments 4,154,221 40,278 2,962,131 19,828 3,879,713 74,367 2,856,313 44,397 Gross derivative instruments, before netting $ 4,379,221 42,250 $ 3,062,131 20,023 $ 4,104,713 77,637 $ 2,956,313 45,189 Less: Legally enforceable master netting agreements 2,915 2,916 24,252 24,254 Less: Cash collateral posted 2,540 766 11,475 600 Total derivative instruments, after netting $ 36,795 $ 16,341 $ 41,910 $ 20,335 (1) One of Webster's counterparty relationships was impacted by a Chicago Mercantile Exchange rulebook amendment, resulting in the presentation of that relationship on a settlement basis, as a single unit of account at September 30, 2017 , versus a netting basis at December 31, 2016. (2) Notional amounts include mandatory forward commitments of $60.5 million , while notional amounts do not include approved floating rate commitments of $21.9 million , at September 30, 2017
Other Derivatives Not Designated For Hedge Accounting	Changes in the fair value of derivatives not qualifying for hedge accounting treatment were recognized as follows: Three months ended September 30, Nine months ended September 30, (In thousands) 2017 2016 2017 2016 Interest rate derivatives $ 1,501 $ 608 $ 1,780 $ 6,515 RPAs 51 110 157 (143 ) Mortgage banking derivatives (219 ) 720 (1,886 ) 357 Other (7 ) (285 ) (634 ) (582 ) Total impact on other non-interest income $ 1,326 $ 1,153 $ (583 ) $ 6,147
Offsetting Liabilities	The following table is presented on a gross basis, prior to the application of counterparty netting agreements: At September 30, 2017 At December 31, 2016 (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 $ 1,972 $ 292 $ 1,051 $ 629 $ 3,270 $ 2,335 $ 935 $ — Non-hedge accounting 4,452 2,623 1,489 340 32,457 21,917 10,540 — Total assets $ 6,424 $ 2,915 $ 2,540 $ 969 $ 35,727 $ 24,252 $ 11,475 $ — Derivative instrument losses: Hedge accounting $ 195 $ 195 $ — $ — $ 792 $ 792 $ — $ — Non-hedge accounting 3,643 2,721 766 156 24,508 23,462 600 446 Total liabilities $ 3,838 $ 2,916 $ 766 $ 156 $ 25,300 $ 24,254 $ 600 $ 446

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2017
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 September 30, 2017 (In thousands) Level 1 Level 2 Level 3 Total Financial assets held at fair value: U.S. Treasury Bills $ 3,596 $ — $ — $ 3,596 Agency CMO — 331,798 — 331,798 Agency MBS — 912,977 — 912,977 Agency CMBS — 584,960 — 584,960 CMBS — 403,433 — 403,433 CLO — 274,583 — 274,583 Trust preferred — 30,937 — 30,937 Corporate debt — 48,878 — 48,878 Total available-for-sale investment securities 3,596 2,587,566 — 2,591,162 Gross derivative instruments, before netting (1) 262 41,988 — 42,250 Investments held in Rabbi Trust 5,278 — — 5,278 Alternative investments — — 6,986 6,986 Originated loans held for sale — 32,855 — 32,855 Total financial assets held at fair value $ 9,136 $ 2,662,409 $ 6,986 $ 2,678,531 Financial liabilities held at fair value: Gross derivative instruments, before netting (1) $ 562 $ 19,461 $ — $ 20,023 At December 31, 2016 (In thousands) Level 1 Level 2 Level 3 Total Financial assets held at fair value: U.S. Treasury Bills $ 734 $ — $ — $ 734 Agency CMO — 419,706 — 419,706 Agency MBS — 954,349 — 954,349 Agency CMBS — 573,272 — 573,272 CMBS — 477,365 — 477,365 CLO — 427,390 — 427,390 Trust preferred — 28,633 — 28,633 Corporate debt — 109,642 — 109,642 Total available-for-sale investment securities 734 2,990,357 — 2,991,091 Gross derivative instruments, before netting (1) 250 77,387 — 77,637 Investments held in Rabbi Trust 5,119 — — 5,119 Alternative investments — — 5,502 5,502 Originated loans held for sale — 60,260 — 60,260 Total financial assets held at fair value $ 6,103 $ 3,128,004 $ 5,502 $ 3,139,609 Financial liabilities held at fair value: Gross derivative instruments, before netting (1) $ 120 $ 45,069 $ — $ 45,189 (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 12: Derivative Financial Instruments
Schedule Of Quantitative Inputs And Assumptions For Items Categorized In Level 3 Of The Fair Value Hierarchy	The following table presents the changes in Level 3 assets and liabilities that are measured at fair value on a recurring basis: (In thousands) Alternative Investments Balance at January 1, 2017 $ 5,502 Unrealized gain included in net income 639 Purchases/capital funding 899 Payments (54 ) Balance at September 30, 2017 $ 6,986
Schedule Of Valuation Methodology And Unobservable Inputs	The table below presents the valuation methodology and unobservable inputs for Level 3 assets measured at fair value on a non-recurring basis as of September 30, 2017 : (Dollars in thousands) Asset Fair Value Valuation Methodology Unobservable Inputs Range of Inputs Collateral dependent impaired loans and leases $ 15,955 Real Estate Appraisals Discount for appraisal type 0% - 20% Discount for costs to sell 0% - 15% OREO $ 2,587 Real Estate Appraisals Discount for appraisal type 0% - 20% Discount for costs to sell 8%
Summary Of Estimated Fair Values Of Significant Financial Instruments	The estimated fair values of selected financial instruments and servicing assets are as follows: At September 30, 2017 At December 31, 2016 (In thousands) Carrying Amount Fair Value Carrying Amount Fair Value Assets: Level 2 Held-to-maturity investment securities $ 4,497,311 $ 4,481,675 $ 4,160,658 $ 4,125,125 Transferred loans held for sale — — 7,317 7,444 Level 3 Loans and leases, net 17,244,618 17,155,002 16,832,268 16,678,106 Mortgage servicing assets 25,140 44,992 24,466 52,075 Alternative investments 10,296 12,539 11,034 13,189 Liabilities: Level 2 Deposit liabilities $ 18,636,744 $ 18,636,744 $ 17,279,049 $ 17,279,049 Time deposits 2,218,491 2,213,155 2,024,808 2,024,395 Securities sold under agreements to repurchase and other borrowings 902,902 905,249 949,526 955,660 FHLB advances (1) 1,507,681 1,512,203 2,842,908 2,825,101 Long-term debt (1) 225,704 235,686 225,514 225,514 (1) The following adjustments to the carrying amount are not included for determination of fair value, see Note 8: Borrowings : • FHLB advances - unamortized premiums on advances •

Retirement Benefit Plans (Table

Retirement Benefit Plans (Tables)	9 Months Ended
	Sep. 30, 2017
Retirement Benefits [Abstract]
Summary of Net Periodic Benefit Cost	The following table summarizes the components of net periodic benefit cost: Three months ended September 30, 2017 2016 (In thousands) Pension Plan SERP Other Benefits Pension Plan SERP Other Benefits Service cost $ 12 $ — $ — $ 11 $ — $ — Interest cost on benefit obligations 1,829 96 19 2,110 98 32 Expected return on plan assets (3,074 ) — — (3,067 ) — — Amortization of prior service cost — — — — — 4 Recognized net loss 1,466 136 (15 ) 1,666 106 8 Net periodic benefit cost $ 233 $ 232 $ 4 $ 720 $ 204 $ 44 Nine months ended September 30, 2017 2016 (In thousands) Pension Plan SERP Other Benefits Pension Plan SERP Other Benefits Service cost $ 37 $ — $ — $ 34 $ — $ — Interest cost on benefit obligations 5,486 281 69 6,331 292 94 Expected return on plan assets (9,222 ) — — (8,596 ) — — Amortization of prior service cost — — — — — 11 Recognized net loss 4,398 561 — 4,998 319 26 Net periodic benefit cost $ 699 $ 842 $ 69 $ 2,767 $ 611 $ 131

Share-Based Plans (Tables)

Share-Based Plans (Tables)	9 Months Ended
	Sep. 30, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Schedule of Allocation of Share-based Compensation Costs by Plan	The following table provides a summary of stock compensation expense recognized in the accompanying Condensed Consolidated Statements of Income: Three months ended September 30, Nine months ended September 30, (In thousands) 2017 2016 2017 2016 Stock options $ — $ — $ — $ 43 Restricted stock 3,007 2,944 9,050 8,515 Total stock compensation expense $ 3,007 $ 2,944 $ 9,050 $ 8,558
Schedule of Share-based Compensation, Activity	The following table provides a summary of the stock compensation plans activity for the nine months ended September 30, 2017 : Restricted Stock Awards Outstanding Stock Options Outstanding Time-Based Performance-Based Number of Shares Weighted-Average Grant Date Fair Value Number of Units Weighted-Average Grant Date Fair Value Number of Shares Weighted-Average Grant Date Fair Value Number of Shares Weighted-Average Exercise Price Outstanding, at January 1, 2017 253,361 $ 32.24 2,158 $ 32.89 116,184 $ 33.62 1,072,974 $ 21.24 Granted 164,953 54.79 8,129 56.07 89,581 56.18 — — Exercised options — — — — — — 279,344 25.80 Vested restricted stock awards (1) 155,390 36.36 6,900 48.82 87,982 40.74 — — Forfeited 14,586 36.44 — — 6,276 42.72 — — Outstanding and exercisable, at September 30, 2017 248,338 $ 43.96 3,387 $ 56.07 111,507 $ 45.61 793,630 $ 19.63 (1)

Segment Reporting (Tables)

Segment Reporting (Tables)	9 Months Ended
	Sep. 30, 2017
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 Banking Community Banking HSA Bank Corporate and Reconciling Consolidated Total At September 30, 2017 $ 9,428,676 $ 8,881,322 $ 76,090 $ 7,964,094 $ 26,350,182 At December 31, 2016 9,069,445 8,721,046 83,987 8,198,051 26,072,529 The following tables present the operating results, including all appropriate allocations, for Webster’s reportable segments and the Corporate and Reconciling category: Three months ended September 30, 2017 (In thousands) Commercial Banking Community Banking HSA Bank Corporate and Reconciling Consolidated Total Net interest income (expense) $ 81,925 $ 96,859 $ 26,713 $ (4,593 ) $ 200,904 Provision (benefit) for loan and lease losses 12,073 (1,923 ) — — 10,150 Net interest income (expense) after provision for loan and lease losses 69,852 98,782 26,713 (4,593 ) 190,754 Non-interest income 13,207 27,079 19,371 6,189 65,846 Non-interest expense 38,339 92,478 27,222 3,784 161,823 Income (loss) before income tax expense 44,720 33,383 18,862 (2,188 ) 94,777 Income tax expense (benefit) 14,363 10,605 6,006 (693 ) 30,281 Net income (loss) $ 30,357 $ 22,778 $ 12,856 $ (1,495 ) $ 64,496 Three months ended September 30, 2016 (In thousands) Commercial Banking Community Banking HSA Bank Corporate and Reconciling Consolidated Total Net interest income (expense) $ 74,265 $ 91,995 $ 20,560 $ (6,623 ) $ 180,197 Provision for loan and lease losses 7,876 6,374 — — 14,250 Net interest income (expense) after provision for loan and lease losses 66,389 85,621 20,560 (6,623 ) 165,947 Non-interest income 15,916 29,130 16,900 4,466 66,412 Non-interest expense 35,793 92,508 23,021 4,775 156,097 Income (loss) before income tax expense 46,512 22,243 14,439 (6,932 ) 76,262 Income tax expense (benefit) 14,957 7,122 4,624 (2,258 ) 24,445 Net income (loss) $ 31,555 $ 15,121 $ 9,815 $ (4,674 ) $ 51,817 Nine months ended September 30, 2017 (In thousands) Commercial Banking Community Banking HSA Bank Corporate and Reconciling Consolidated Total Net interest income (expense) $ 239,118 $ 286,351 $ 76,339 $ (10,453 ) $ 591,355 Provision for loan and lease losses 29,562 (1,662 ) — — 27,900 Net interest income (expense) after provision for loan and lease losses 209,556 288,013 76,339 (10,453 ) 563,455 Non-interest income 39,163 80,516 58,392 15,368 193,439 Non-interest expense 113,767 281,979 84,211 10,069 490,026 Income (loss) before income tax expense 134,952 86,550 50,520 (5,154 ) 266,868 Income tax expense (benefit) 41,125 26,374 15,395 (1,572 ) 81,322 Net income (loss) $ 93,827 $ 60,176 $ 35,125 $ (3,582 ) $ 185,546 Nine months ended September 30, 2016 (In thousands) Commercial Banking Community Banking HSA Bank Corporate and Reconciling Consolidated Total Net interest income (expense) $ 211,422 $ 274,186 $ 60,484 $ (12,838 ) $ 533,254 Provision for loan and lease losses 29,765 14,085 — — 43,850 Net interest income (expense) after provision for loan and lease losses 181,657 260,101 60,484 (12,838 ) 489,404 Non-interest income 41,819 83,248 54,969 13,825 193,861 Non-interest expense 103,336 276,045 71,966 9,973 461,320 Income (loss) before income tax expense 120,140 67,304 43,487 (8,986 ) 221,945 Income tax expense (benefit) 39,233 21,979 14,201 (2,935 ) 72,478 Net income (loss) $ 80,907 $ 45,325 $ 29,286 $ (6,051 ) $ 149,467

Commitments and Contingencies (

Commitments and Contingencies (Tables)	9 Months Ended
	Sep. 30, 2017
Commitments and Contingencies Disclosure [Abstract]
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: (In thousands) At September 30, 2017 At December 31, 2016 Commitments to extend credit $ 5,043,151 $ 5,224,280 Standby letter of credit 159,485 128,985 Commercial letter of credit 42,007 46,497 Total credit-related financial instruments with off-balance sheet risk $ 5,244,643 $ 5,399,762
Reserve For Unfunded Credit Commitments	The following table provides a summary of activity in the reserve for loan repurchases: Three months ended September 30, Nine months ended September 30, (In thousands) 2017 2016 2017 2016 Beginning balance $ 843 $ 992 $ 790 $ 1,192 Provision (benefit) charged to expense 25 37 78 (64 ) Repurchased loans and settlements charged off (18 ) — (18 ) (99 ) Ending balance $ 850 $ 1,029 $ 850 $ 1,029 Three months ended September 30, Nine months ended September 30, (In thousands) 2017 2016 2017 2016 Beginning balance $ 2,544 $ 2,319 $ 2,287 $ 2,119 Provision charged to expense — 172 257 372 Ending balance $ 2,544 $ 2,491 $ 2,544 $ 2,491

Investment Securities (Summary

Investment Securities (Summary Of Investment Securities) (Detail) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Available-for-sale Securities [Abstract]
Amortized Cost	$ 2,612,905	$ 3,015,763
Unrealized Gains	10,248	16,226
Unrealized Losses	(31,991)	(40,898)
Fair Value	2,591,162	2,991,091
Held-to-maturity Securities [Abstract]
Amortized Cost	4,497,311	4,160,658
Unrealized Gains	34,302	37,567
Unrealized Losses	(49,938)	(73,100)
Fair Value	4,481,675	4,125,125
US Treasury Bill Securities [Member]
Available-for-sale Securities [Abstract]
Amortized Cost	3,596	734
Unrealized Gains	0	0
Unrealized Losses	0	0
Fair Value	3,596	734
Agency collateralized mortgage obligations (CMOs) [Member]
Available-for-sale Securities [Abstract]
Amortized Cost	332,341	419,865
Unrealized Gains	2,573	3,344
Unrealized Losses	(3,116)	(3,503)
Fair Value	331,798	419,706
Held-to-maturity Securities [Abstract]
Amortized Cost	276,367	339,455
Unrealized Gains	1,138	1,977
Unrealized Losses	(3,030)	(3,824)
Fair Value	274,475	337,608
Agency mortgage-backed securities (MBS) [Member]
Available-for-sale Securities [Abstract]
Amortized Cost	923,819	969,460
Unrealized Gains	3,214	4,398
Unrealized Losses	(14,056)	(19,509)
Fair Value	912,977	954,349
Held-to-maturity Securities [Abstract]
Amortized Cost	2,549,500	2,317,449
Unrealized Gains	24,275	26,388
Unrealized Losses	(30,012)	(41,768)
Fair Value	2,543,763	2,302,069
Agency commercial mortgage-backed securities (ACMBS) [Member]
Available-for-sale Securities [Abstract]
Amortized Cost	599,165	587,776
Unrealized Gains	0	63
Unrealized Losses	(14,205)	(14,567)
Fair Value	584,960	573,272
Held-to-maturity Securities [Abstract]
Amortized Cost	708,229	547,726
Unrealized Gains	280	694
Unrealized Losses	(3,549)	(1,348)
Fair Value	704,960	547,072
Non-agency Commercial mortgage-backed securities (CMBS) [Member]
Available-for-sale Securities [Abstract]
Amortized Cost	402,015	473,974
Unrealized Gains	1,539	4,093
Unrealized Losses	(121)	(702)
Fair Value	403,433	477,365
Held-to-maturity Securities [Abstract]
Amortized Cost	257,361	298,538
Unrealized Gains	3,394	4,107
Unrealized Losses	(197)	(411)
Fair Value	260,558	302,234
CLO [Member]
Available-for-sale Securities [Abstract]
Amortized Cost	273,172	425,083
Unrealized Gains	1,572	2,826
Unrealized Losses	(161)	(519)
Fair Value	274,583	427,390
Single issuer trust preferred securities [Member]
Available-for-sale Securities [Abstract]
Amortized Cost	30,463	30,381
Unrealized Gains	676	0
Unrealized Losses	(202)	(1,748)
Fair Value	30,937	28,633
Corporate debt securities [Member]
Available-for-sale Securities [Abstract]
Amortized Cost	48,334	108,490
Unrealized Gains	674	1,502
Unrealized Losses	(130)	(350)
Fair Value	48,878	109,642
Municipal bonds and notes [Member]
Held-to-maturity Securities [Abstract]
Amortized Cost	705,411	655,813
Unrealized Gains	5,213	4,389
Unrealized Losses	(13,150)	(25,749)
Fair Value	697,474	634,453
Private Label MBS [Member]
Held-to-maturity Securities [Abstract]
Amortized Cost	443	1,677
Unrealized Gains	2	12
Unrealized Losses	0	0
Fair Value	$ 445	$ 1,689

Investment Securities (Other Th

Investment Securities (Other Than Temporary Impairment Credit Losses Recognized In Earnings) (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Roll Forward]
Balance of OTTI, beginning of period	$ 3,231	$ 3,437	$ 3,243	$ 3,288
Reduction for securities sold, called	(1,028)	(30)	(1,166)	(30)
Additions for OTTI not previously recognized in earnings	0	0	126	149
Balance of OTTI, end of period	$ 2,203	$ 3,407	$ 2,203	$ 3,407

Investment Securities (Summar44

Investment Securities (Summary Of Gross Unrealized Losses Not Considered OTTI) (Detail) $ in Thousands	Sep. 30, 2017USD ($)holding	Dec. 31, 2016USD ($)holding
Schedule of Investments [Line Items]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	$ 986,229	$ 1,236,547
Available for sale, Unrealized Losses - Less Than Twelve Months	(12,877)	(27,316)
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	659,271	470,314
Available for sale, Unrealized Losses - Twelve Months or Longer	$ (19,114)	$ (13,582)
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions | holding	169	168
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	$ 1,645,500	$ 1,706,861
Available for sale, Unrealized Losses - Total	(31,991)	(40,898)
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	1,688,111	2,351,350
Held-to-maturity, Unrealized Losses - Less Than Twelve Months	(14,274)	(63,785)
Held-to-maturity Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	1,089,959	292,225
Held-to-maturity, Unrealized Losses, Twelve Months or Longer	$ (35,664)	$ (9,315)
Held-to-maturity, Number of Holdings - Total | holding	366	395
Held-to-maturity, Fair Value - Total	$ 2,778,070	$ 2,643,575
Held-to-maturity, Unrealized Losses - Total	(49,938)	(73,100)
Agency CMO [Member]
Schedule of Investments [Line Items]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	75,042	107,853
Available for sale, Unrealized Losses - Less Than Twelve Months	(1,002)	(2,168)
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	70,167	67,351
Available for sale, Unrealized Losses - Twelve Months or Longer	$ (2,114)	$ (1,335)
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions | holding	16	15
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	$ 145,209	$ 175,204
Available for sale, Unrealized Losses - Total	(3,116)	(3,503)
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	82,839	163,439
Held-to-maturity, Unrealized Losses - Less Than Twelve Months	(880)	(3,339)
Held-to-maturity Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	83,103	17,254
Held-to-maturity, Unrealized Losses, Twelve Months or Longer	$ (2,150)	$ (485)
Held-to-maturity, Number of Holdings - Total | holding	19	16
Held-to-maturity, Fair Value - Total	$ 165,942	$ 180,693
Held-to-maturity, Unrealized Losses - Total	(3,030)	(3,824)
Agency MBS [Member]
Schedule of Investments [Line Items]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	464,031	512,075
Available for sale, Unrealized Losses - Less Than Twelve Months	(5,169)	(10,503)
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	303,770	252,779
Available for sale, Unrealized Losses - Twelve Months or Longer	$ (8,887)	$ (9,006)
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions | holding	104	97
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	$ 767,801	$ 764,854
Available for sale, Unrealized Losses - Total	(14,056)	(19,509)
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	870,376	1,394,623
Held-to-maturity, Unrealized Losses - Less Than Twelve Months	(7,948)	(32,942)
Held-to-maturity Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	775,331	273,779
Held-to-maturity, Unrealized Losses, Twelve Months or Longer	$ (22,064)	$ (8,826)
Held-to-maturity, Number of Holdings - Total | holding	157	150
Held-to-maturity, Fair Value - Total	$ 1,645,707	$ 1,668,402
Held-to-maturity, Unrealized Losses - Total	(30,012)	(41,768)
Agency CMBS [Member]
Schedule of Investments [Line Items]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	306,025	554,246
Available for sale, Unrealized Losses - Less Than Twelve Months	(6,240)	$ (14,567)
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	278,935
Available for sale, Unrealized Losses - Twelve Months or Longer	$ (7,965)
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions | holding	34	32
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	$ 584,960	$ 554,246
Available for sale, Unrealized Losses - Total	(14,205)	(14,567)
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	570,781	347,725
Held-to-maturity, Unrealized Losses - Less Than Twelve Months	(3,504)	$ (1,348)
Held-to-maturity Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	4,730
Held-to-maturity, Unrealized Losses, Twelve Months or Longer	$ (45)
Held-to-maturity, Number of Holdings - Total | holding	45	25
Held-to-maturity, Fair Value - Total	$ 575,511	$ 347,725
Held-to-maturity, Unrealized Losses - Total	(3,549)	(1,348)
Non-agency CMBS [Member]
Schedule of Investments [Line Items]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	39,775	12,427
Available for sale, Unrealized Losses - Less Than Twelve Months	$ (121)	(24)
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		63,930
Available for sale, Unrealized Losses - Twelve Months or Longer		$ (678)
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions | holding	5	12
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	$ 39,775	$ 76,357
Available for sale, Unrealized Losses - Total	(121)	(702)
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	40,150	60,768
Held-to-maturity, Unrealized Losses - Less Than Twelve Months	(197)	$ (411)
Held-to-maturity Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	$ 250
Held-to-maturity, Number of Holdings - Total | holding	5	8
Held-to-maturity, Fair Value - Total	$ 40,400	$ 60,768
Held-to-maturity, Unrealized Losses - Total	(197)	(411)
CLO [Member]
Schedule of Investments [Line Items]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	82,989	49,946
Available for sale, Unrealized Losses - Less Than Twelve Months	$ (161)	(54)
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		50,237
Available for sale, Unrealized Losses - Twelve Months or Longer		$ (465)
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions | holding	5	5
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	$ 82,989	$ 100,183
Available for sale, Unrealized Losses - Total	(161)	(519)
Single issuer trust preferred securities [Member]
Schedule of Investments [Line Items]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	12,570	0
Available for sale, Unrealized Losses - Less Than Twelve Months	(97)
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	4,574	28,633
Available for sale, Unrealized Losses - Twelve Months or Longer	$ (105)	$ (1,748)
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions | holding	3	5
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	$ 17,144	$ 28,633
Available for sale, Unrealized Losses - Total	(202)	(1,748)
Corporate Debt Securities [Member]
Schedule of Investments [Line Items]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	5,797
Available for sale, Unrealized Losses - Less Than Twelve Months	(87)
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	1,825	7,384
Available for sale, Unrealized Losses - Twelve Months or Longer	$ (43)	$ (350)
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions | holding	2	2
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	$ 7,622	$ 7,384
Available for sale, Unrealized Losses - Total	(130)	(350)
Municipal bonds and notes [Member]
Schedule of Investments [Line Items]
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	123,965	384,795
Held-to-maturity, Unrealized Losses - Less Than Twelve Months	(1,745)	(25,745)
Held-to-maturity Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	226,545	1,192
Held-to-maturity, Unrealized Losses, Twelve Months or Longer	$ (11,405)	$ (4)
Held-to-maturity, Number of Holdings - Total | holding	140	196
Held-to-maturity, Fair Value - Total	$ 350,510	$ 385,987
Held-to-maturity, Unrealized Losses - Total	$ (13,150)	$ (25,749)

Investment Securities (Summar45

Investment Securities (Summary Of Debt Securities By Contractual Maturity) (Detail) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Available-for-sale Securities, Debt Maturities, Amortized Cost Basis, Fiscal Year Maturity [Abstract]
Available-for-sale, Amortized Cost - Due in one year or less	$ 18,668
Available-for-sale, Amortized Cost - Due after one year through five years	40,246
Available-for-sale, Amortized Cost - Due after five through ten years	381,547
Available-for-sale, Amortized Cost - Due after ten years	2,172,444
Available-for-sale, Amortized Cost - Total debt securities	2,612,905
Available-for-sale Securities, Debt Maturities, Fair Value, Fiscal Year Maturity [Abstract]
Available-for-sale, Fair Value - Due in one year or less	18,714
Available-for-sale, Fair Value - Due after one year through five years	40,748
Available-for-sale, Fair Value - Due after five through ten years	383,721
Available-for-sale, Fair Value - Due after ten years	2,147,979
Available-for-sale, Fair Value - Total debt securities	2,591,162
Held-to-maturity Securities, Debt Maturities, Single Maturity Date, Amortized Cost Basis [Abstract]
Held-to-maturity, Amortized Cost - Due in one year or less	40,146
Held-to-maturity, Amortized Cost - Due after one year through five years	13,410
Held-to-maturity, Amortized Cost - Due after five through ten years	38,323
Held-to-maturity, Amortized Cost - Due after ten years	4,405,432
Amortized Cost	4,497,311	$ 4,160,658
Held-to-maturity Securities, Debt Maturities, Fair Value, Fiscal Year Maturity [Abstract]
Held to maturity, Fair Value - Due in one year or less	40,753
Held-to-maturity, Fair Value - Due after one year through five years	13,684
Held to maturity, Fair Value - Due after five through ten years	39,102
Held to maturity, Fair Value - Due after ten years	4,388,136
Fair Value	$ 4,481,675	$ 4,125,125

Investment Securities (Narrativ

Investment Securities (Narrative) (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Schedule of Investments [Line Items]
Additions for OTTI not previously recognized in earnings	$ 0	$ 0	$ 126	$ 149
Available-for-sale - Accumulated Gross Unrealized Losses Before Tax	(31,991)		(31,991)		$ (40,898)
Held-to-maturity Securities, Accumulated Unrecognized Holding Loss	(49,938)		(49,938)		(73,100)
Investment securities available-for-sale, at fair value	2,591,162		2,591,162		2,991,091
Pledged Financial Instruments, Not Separately Reported, Securities	2,800,000		2,800,000		2,500,000
Agency collateralized mortgage obligations (CMOs) [Member]
Schedule of Investments [Line Items]
Available-for-sale - Accumulated Gross Unrealized Losses Before Tax	(3,116)		(3,116)		(3,503)
Held-to-maturity Securities, Accumulated Unrecognized Holding Loss	(3,030)		(3,030)		(3,824)
Investment securities available-for-sale, at fair value	331,798		331,798		419,706
Agency MBS [Member]
Schedule of Investments [Line Items]
Available-for-sale - Accumulated Gross Unrealized Losses Before Tax	(14,056)		(14,056)		(19,509)
Held-to-maturity Securities, Accumulated Unrecognized Holding Loss	(30,012)		(30,012)		(41,768)
Investment securities available-for-sale, at fair value	912,977		912,977		954,349
Agency CMBS [Member]
Schedule of Investments [Line Items]
Available-for-sale - Accumulated Gross Unrealized Losses Before Tax	(14,205)		(14,205)		(14,567)
Held-to-maturity Securities, Accumulated Unrecognized Holding Loss	(3,549)		(3,549)		(1,348)
Investment securities available-for-sale, at fair value	584,960		584,960		573,272
Non-agency Commercial mortgage-backed securities (CMBS) [Member]
Schedule of Investments [Line Items]
Available-for-sale - Accumulated Gross Unrealized Losses Before Tax	(121)		(121)		(702)
Held-to-maturity Securities, Accumulated Unrecognized Holding Loss	(197)		(197)		(411)
Investment securities available-for-sale, at fair value	403,433		403,433		477,365
CLO [Member]
Schedule of Investments [Line Items]
Available-for-sale - Accumulated Gross Unrealized Losses Before Tax	(161)		(161)		(519)
Investment securities available-for-sale, at fair value	274,583		274,583		427,390
Single issuer trust preferred securities [Member]
Schedule of Investments [Line Items]
Available-for-sale - Accumulated Gross Unrealized Losses Before Tax	(202)		(202)		(1,748)
Investment securities available-for-sale, at fair value	30,937		30,937		28,633
Corporate Debt Securities [Member]
Schedule of Investments [Line Items]
Available-for-sale - Accumulated Gross Unrealized Losses Before Tax	(130)		(130)		(350)
Investment securities available-for-sale, at fair value	48,878		48,878		109,642
Municipal bonds and notes [Member]
Schedule of Investments [Line Items]
Held-to-maturity Securities, Accumulated Unrecognized Holding Loss	(13,150)		(13,150)		$ (25,749)
Callable at the option of the counterparty [Member]
Schedule of Investments [Line Items]
Investment securities available-for-sale, at fair value	$ 1,200,000		$ 1,200,000

Investment Securities (Narrat47

Investment Securities (Narrative) (Summary Of Realized Gain (Loss) on Investments (Detail) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Gain (Loss) on Investments [Line Items]
Available-for-sale Securities, Gross Realized Gains (Losses), Sale Proceeds	$ 0	$ 259,300
Gross realized gains on sales		2,900
Less: Gross realized losses on sales		$ 2,500

Variable Interest Entities (Var

Variable Interest Entities (Variable Interest Entity, Consolidated, Carrying Amount, Assets) (Details) - Variable Interest Entity, Not Primary Beneficiary [Member] - USD ($) $ in Millions	Sep. 30, 2017	Dec. 31, 2016
Other Assets [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Consolidated, Carrying Amount, Assets	$ 35.7	$ 22.8
Accounts Payable and Accrued Liabilities [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Consolidated, Carrying Amount, Liabilities	24.3	14
Other Investments [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Consolidated, Carrying Amount, Assets	13	12.3
Unfunded Loan Commitment [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount	$ 22.4	$ 19.9

Loans and Leases (Detail)

Loans and Leases (Detail) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016	Sep. 30, 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	$ 17,446,421	$ 17,026,588	$ 16,623,401
Unamortized premiums	20,800	17,300
Pledged Financial Instruments, Not Separately Reported, Loans Receivable Pledged as Collateral	6,700,000
Residential Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	4,499,441	4,254,682	4,234,047
Consumer Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	2,566,983	2,684,500	2,707,343
Commercial Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	5,348,303	4,940,931	4,779,802
Commercial Real Estate Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	4,464,917	4,510,846	4,280,513
Finance Leases Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	$ 566,777	$ 635,629	$ 621,696

Loans and Leases (Summary Of Lo

Loans and Leases (Summary Of Loan And Lease Portfolio Aging By Class Of Loan) (Detail) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016	Sep. 30, 2016
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	$ 197,366	$ 175,864
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing	934	749
Financing Receivable, Recorded Investment, Nonaccrual Status	163,763	133,816
Financing Receivable, Recorded Investment, Current	17,249,055	16,850,724
Loans and leases	17,446,421	17,026,588	$ 16,623,401
Financing Receivables, 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	22,019	28,337
Financing Receivables, 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	10,650	12,962
Residential Portfolio Segment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	57,399	58,519
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing	0	0
Financing Receivable, Recorded Investment, Nonaccrual Status	45,676	47,279
Financing Receivable, Recorded Investment, Current	4,442,042	4,196,163
Loans and leases	4,499,441	4,254,682	4,234,047
Residential Portfolio Segment [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	8,069	8,631
Residential Portfolio Segment [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	3,654	2,609
Consumer Portfolio Segment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases	2,566,983	2,684,500	2,707,343
Consumer Portfolio Segment [Member] | Home Equity Loan [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	49,403	50,539
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing	0	0
Financing Receivable, Recorded Investment, Nonaccrual Status	37,105	35,926
Financing Receivable, Recorded Investment, Current	2,269,468	2,359,354
Loans and leases	2,318,871	2,409,893
Consumer Portfolio Segment [Member] | Home Equity Loan [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	7,613	8,831
Consumer Portfolio Segment [Member] | Home Equity Loan [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	4,685	5,782
Consumer Portfolio Segment [Member] | Consumer Borrower [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	5,537	5,381
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing	0	0
Financing Receivable, Recorded Investment, Nonaccrual Status	1,859	1,663
Financing Receivable, Recorded Investment, Current	242,575	269,226
Loans and leases	248,112	274,607
Consumer Portfolio Segment [Member] | Consumer Borrower [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	2,224	2,233
Consumer Portfolio Segment [Member] | Consumer Borrower [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	1,454	1,485
Commercial Portfolio Segment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases	5,348,303	4,940,931	4,779,802
Commercial Portfolio Segment [Member] | Commercial and Industrial Sector [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	62,161	40,898
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing	934	749
Financing Receivable, Recorded Investment, Nonaccrual Status	58,915	38,190
Financing Receivable, Recorded Investment, Current	4,402,543	4,094,727
Loans and leases	4,464,704	4,135,625
Commercial Portfolio Segment [Member] | Commercial and Industrial Sector [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	1,948	1,382
Commercial Portfolio Segment [Member] | Commercial and Industrial Sector [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	364	577
Commercial Portfolio Segment [Member] | Asset Based Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	8,558	0
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing	0	0
Financing Receivable, Recorded Investment, Nonaccrual Status	8,558	0
Financing Receivable, Recorded Investment, Current	875,041	805,306
Loans and leases	883,599	805,306
Commercial Portfolio Segment [Member] | Asset Based Loans [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	0	0
Commercial Portfolio Segment [Member] | Asset Based Loans [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	0	0
Commercial Real Estate Portfolio Segment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases	4,464,917	4,510,846	4,280,513
Commercial Real Estate Portfolio Segment [Member] | Construction Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	477	662
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing	0	0
Financing Receivable, Recorded Investment, Nonaccrual Status	477	662
Financing Receivable, Recorded Investment, Current	290,474	374,398
Loans and leases	290,951	375,060
Commercial Real Estate Portfolio Segment [Member] | Construction Loans [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	0	0
Commercial Real Estate Portfolio Segment [Member] | Construction Loans [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	0	0
Commercial Real Estate Portfolio Segment [Member] | Real Estate Loan [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	12,394	18,044
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing	0	0
Financing Receivable, Recorded Investment, Nonaccrual Status	10,603	9,871
Financing Receivable, Recorded Investment, Current	4,161,572	4,117,742
Loans and leases	4,173,966	4,135,786
Commercial Real Estate Portfolio Segment [Member] | Real Estate Loan [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	1,347	6,357
Commercial Real Estate Portfolio Segment [Member] | Real Estate Loan [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	444	1,816
Finance Leases Portfolio Segment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	1,437	1,821
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing	0	0
Financing Receivable, Recorded Investment, Nonaccrual Status	570	225
Financing Receivable, Recorded Investment, Current	565,340	633,808
Loans and leases	566,777	635,629	$ 621,696
Finance Leases Portfolio Segment [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	818	903
Finance Leases Portfolio Segment [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	$ 49	$ 693

Loans and Leases (Narrative) (D

Loans and Leases (Narrative) (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Loans and Leases Receivable Disclosure [Abstract]
Loans and Leases Receivable, Impaired, Interest Lost on Nonaccrual Loans	$ 2.8	$ 3.7	$ 6.4	$ 8.4
Write-down of TDR's	$ (0.4)	$ (3)	$ (3)	$ (17.9)

Loans and Leases (Allowance For

Loans and Leases (Allowance For Loan And Lease Losses By Portfolio Segment) (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Dec. 31, 2016	Sep. 30, 2016
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance, beginning of period	$ 199,578	$ 180,428	$ 194,320	$ 174,990
Provision (benefit) charged to expense	10,150	14,250	27,900	43,850
Charge-offs	(10,654)	(9,424)	(26,910)	(38,108)
Recoveries	2,729	2,671	6,493	7,193
Balance, end of period	199,578	180,428	194,320	174,990	$ 201,803	$ 194,320	$ 187,925
ALLL, Individually evaluated for impairment					17,786		19,503
ALLL, Collectively evaluated for impairment					184,017		168,422
Loan and lease balances, Individually evaluated for impairment					270,156		257,711
Loan and lease balances, Collectively evaluated for impairment					17,176,265		16,365,690
Loans and leases					17,446,421	17,026,588	16,623,401
Residential Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance, beginning of period	18,427	24,413	23,226	25,876
Provision (benefit) charged to expense	(348)	1,076	(4,436)	991
Charge-offs	(585)	(1,304)	(1,940)	(3,536)
Recoveries	280	554	924	1,408
Balance, end of period	18,427	24,413	23,226	25,876	17,774	23,226	24,739
ALLL, Individually evaluated for impairment					4,925		9,443
ALLL, Collectively evaluated for impairment					12,849		15,296
Loan and lease balances, Individually evaluated for impairment					116,706		122,020
Loan and lease balances, Collectively evaluated for impairment					4,382,735		4,112,027
Loans and leases					4,499,441	4,254,682	4,234,047
Consumer Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance, beginning of period	42,488	42,956	45,233	42,052
Provision (benefit) charged to expense	(41)	4,985	6,847	12,458
Charge-offs	(6,197)	(5,259)	(18,273)	(14,236)
Recoveries	1,894	1,313	4,337	3,721
Balance, end of period	42,488	42,956	45,233	42,052	38,144	45,233	43,995
ALLL, Individually evaluated for impairment					1,689		3,005
ALLL, Collectively evaluated for impairment					36,455		40,990
Loan and lease balances, Individually evaluated for impairment					46,224		46,208
Loan and lease balances, Collectively evaluated for impairment					2,520,759		2,661,135
Loans and leases					2,566,983	2,684,500	2,707,343
Commercial Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance, beginning of period	79,964	73,822	71,905	66,686
Provision (benefit) charged to expense	12,166	4,351	21,905	25,447
Charge-offs	(3,002)	(2,561)	(5,321)	(17,294)
Recoveries	466	370	1,105	1,143
Balance, end of period	79,964	73,822	71,905	66,686	89,594	71,905	75,982
ALLL, Individually evaluated for impairment					10,844		6,579
ALLL, Collectively evaluated for impairment					78,750		69,403
Loan and lease balances, Individually evaluated for impairment					85,385		58,197
Loan and lease balances, Collectively evaluated for impairment					5,262,918		4,721,605
Loans and leases					5,348,303	4,940,931	4,779,802
Commercial Real Estate Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance, beginning of period	52,402	33,622	47,477	34,889
Provision (benefit) charged to expense	(2,129)	2,953	2,987	3,921
Charge-offs	(749)	0	(951)	(2,521)
Recoveries	10	194	21	480
Balance, end of period	52,402	33,622	47,477	34,889	49,534	47,477	36,769
ALLL, Individually evaluated for impairment					290		467
ALLL, Collectively evaluated for impairment					49,244		36,302
Loan and lease balances, Individually evaluated for impairment					18,199		24,423
Loan and lease balances, Collectively evaluated for impairment					4,446,718		4,256,090
Loans and leases					4,464,917	4,510,846	4,280,513
Finance Leases Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance, beginning of period	6,297	5,615	6,479	5,487
Provision (benefit) charged to expense	502	885	597	1,033
Charge-offs	(121)	(300)	(425)	(521)
Recoveries	79	240	106	441
Balance, end of period	$ 6,297	$ 5,615	$ 6,479	$ 5,487	6,757	6,479	6,440
ALLL, Individually evaluated for impairment					38		9
ALLL, Collectively evaluated for impairment					6,719		6,431
Loan and lease balances, Individually evaluated for impairment					3,642		6,863
Loan and lease balances, Collectively evaluated for impairment					563,135		614,833
Loans and leases					$ 566,777	$ 635,629	$ 621,696

Loans and Leases (Impaired Loan

Loans and Leases (Impaired Loans And Leases By Class) (Detail) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	$ 299,588	$ 273,364
Total Recorded Investment	270,157	249,355
Recorded Investment No Allowance	102,374	96,795
Recorded Investment With Allowance	167,783	152,560
Related Valuation Allowance	17,786	18,593
Residential Portfolio Segment [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	127,986	131,468
Total Recorded Investment	116,706	119,424
Recorded Investment No Allowance	27,961	21,068
Recorded Investment With Allowance	88,745	98,356
Related Valuation Allowance	4,925	8,090
Consumer Portfolio Segment [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance		52,432
Total Recorded Investment		45,719
Recorded Investment No Allowance		22,746
Recorded Investment With Allowance		22,973
Related Valuation Allowance		2,903
Consumer Portfolio Segment [Member] | Home Equity Loan [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	51,496
Total Recorded Investment	46,225
Recorded Investment No Allowance	21,833
Recorded Investment With Allowance	24,392
Related Valuation Allowance	1,689
Commercial Portfolio Segment [Member] | Commercial and Industrial Sector [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	88,221	57,732
Total Recorded Investment	76,827	53,037
Recorded Investment No Allowance	28,124	26,006
Recorded Investment With Allowance	48,703	27,031
Related Valuation Allowance	10,844	7,422
Commercial Portfolio Segment [Member] | Asset Based Loans [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	8,558	0
Total Recorded Investment	8,558	0
Recorded Investment No Allowance	8,558	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	19,026	24,146
Total Recorded Investment	17,725	23,568
Recorded Investment No Allowance	12,894	19,591
Recorded Investment With Allowance	4,831	3,977
Related Valuation Allowance	271	169
Commercial Real Estate Portfolio Segment [Member] | Construction Loans [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	580	1,188
Total Recorded Investment	474	1,187
Recorded Investment No Allowance	0	1,187
Recorded Investment With Allowance	474	0
Related Valuation Allowance	19	0
Finance Leases Portfolio Segment [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	3,721	6,398
Total Recorded Investment	3,642	6,420
Recorded Investment No Allowance	3,004	6,197
Recorded Investment With Allowance	638	223
Related Valuation Allowance	$ 38	$ 9

Loans and Leases (Interest Inco

Loans and Leases (Interest Income From Impaired Loans And Leases, By Class) (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	$ 277,661	$ 262,717	$ 259,757	$ 268,442
Accrued Interest Income	1,743	1,954	5,344	6,201
Cash Basis Interest Income	531	542	1,794	1,672
Residential Portfolio Segment [Member]
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	118,841	124,993	118,065	128,234
Accrued Interest Income	1,027	1,070	3,133	3,309
Cash Basis Interest Income	285	304	986	918
Consumer Portfolio Segment [Member] | Home Equity Loan [Member]
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	46,753	46,892	45,972	47,317
Accrued Interest Income	341	336	998	1,029
Cash Basis Interest Income	246	238	808	754
Commercial Portfolio Segment [Member] | Commercial and Industrial Sector [Member]
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	81,816	58,874	64,932	57,389
Accrued Interest Income	249	352	704	1,299
Cash Basis Interest Income	0	0	0	0
Commercial Portfolio Segment [Member] | Asset Based Loans [Member]
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	4,279	0	4,279	0
Accrued Interest Income	0	0		0
Cash Basis Interest Income	0	0	0	0
Commercial Real Estate Portfolio Segment [Member] | Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	20,249	23,930	20,647	26,689
Accrued Interest Income	96	77	329	374
Cash Basis Interest Income	0	0	0	0
Commercial Real Estate Portfolio Segment [Member] | Construction Loans [Member]
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	828	4,386	831	5,171
Accrued Interest Income	0	12	12	81
Cash Basis Interest Income	0	0	0	0
Finance Leases Portfolio Segment [Member]
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	4,895	3,642	5,031	3,642
Accrued Interest Income	30	107	168	109
Cash Basis Interest Income	$ 0	$ 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	Sep. 30, 2017	Dec. 31, 2016	Sep. 30, 2016
Financing Receivable, Recorded Investment [Line Items]
Loans and leases	$ 17,446,421	$ 17,026,588	$ 16,623,401
Commercial Portfolio Segment [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases	5,348,303	4,940,931	4,779,802
Commercial Portfolio Segment [Member] | (1) - (6) Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases	5,037,439	4,655,007
Commercial Portfolio Segment [Member] | (7) Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases	108,828	56,240
Commercial Portfolio Segment [Member] | (8) Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases	192,161	226,603
Commercial Portfolio Segment [Member] | (9) Doubtful [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases	9,875	3,081
Commercial Real Estate Portfolio Segment [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases	4,464,917	4,510,846	4,280,513
Commercial Real Estate Portfolio Segment [Member] | (1) - (6) Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases	4,266,658	4,357,458
Commercial Real Estate Portfolio Segment [Member] | (7) Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases	85,926	69,023
Commercial Real Estate Portfolio Segment [Member] | (8) Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases	112,333	84,365
Commercial Real Estate Portfolio Segment [Member] | (9) Doubtful [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases	0	0
Finance Leases Portfolio Segment [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases	566,777	635,629	$ 621,696
Finance Leases Portfolio Segment [Member] | (1) - (6) Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases	548,298	618,084
Finance Leases Portfolio Segment [Member] | (7) Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases	3,557	1,324
Finance Leases Portfolio Segment [Member] | (8) Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases	14,922	16,221
Finance Leases Portfolio Segment [Member] | (9) Doubtful [Member]
Financing Receivable, Recorded Investment [Line Items]
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	Sep. 30, 2017	Jun. 30, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Dec. 31, 2015
Financing Receivable, Modifications [Line Items]
Total recorded investment of TDRs	$ 218,350		$ 223,528
Specific reserves for TDRs included in the balance of ALLL	201,803	$ 199,578	194,320	$ 187,925	$ 180,428	$ 174,990
Additional funds committed to borrowers in TDR status	3,944		459
Performing Financial Instruments [Member]
Financing Receivable, Modifications [Line Items]
Total recorded investment of TDRs	135,774		147,809
Nonperforming Financial Instruments [Member]
Financing Receivable, Modifications [Line Items]
Total recorded investment of TDRs	82,576		75,719
Nonperforming Financial Instruments [Member] | Troubled Debt Restructures [Member]
Financing Receivable, Modifications [Line Items]
Specific reserves for TDRs included in the balance of ALLL	$ 11,837		$ 14,583

Loans and Leases (Information o

Loans and Leases (Information on How Loans and Leases were Modified as a TDR) (Detail) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2017USD ($)loan	Sep. 30, 2016USD ($)loan	Sep. 30, 2017USD ($)loan		Sep. 30, 2016USD ($)loan
Financing Receivable, Modifications [Line Items]
Number of Loans and Leases | loan		35	38	151		133
Post-Modification Recorded Investment | $	[1]	$ 3,869	$ 10,987	$ 26,596		$ 34,367
Home Equity Loan [Member] | Adjusted Interest Rate [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans and Leases | loan		1	0
Post-Modification Recorded Investment | $		$ 247	$ 0
Residential Portfolio Segment [Member] | Extended Maturity [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans and Leases | loan		0	4	9		11
Post-Modification Recorded Investment | $	[1]	$ 0	$ 967	$ 1,390		$ 1,969
Residential Portfolio Segment [Member] | Adjusted Interest Rate [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans and Leases | loan		0	1	2		2
Post-Modification Recorded Investment | $	[1]	$ 0	$ 292	$ 335		$ 528
Residential Portfolio Segment [Member] | Maturity/Rate Combined [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans and Leases | loan		4	3	9		10
Post-Modification Recorded Investment | $	[1]	$ 570	$ 290	$ 1,416		$ 1,185
Residential Portfolio Segment [Member] | Other [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans and Leases | loan	[2]	6	3	32		18
Post-Modification Recorded Investment | $	[1],[2]	$ 1,357	$ 299	$ 5,471		$ 3,190
Consumer Portfolio Segment [Member] | Adjusted Interest Rate [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans and Leases | loan				1		0
Post-Modification Recorded Investment | $				$ 247		$ 0	[1]
Consumer Portfolio Segment [Member] | Home Equity Loan [Member] | Extended Maturity [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans and Leases | loan		2	2	8		9
Post-Modification Recorded Investment | $	[1]	$ 158	$ 89	$ 822		$ 381
Consumer Portfolio Segment [Member] | Home Equity Loan [Member] | Maturity/Rate Combined [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans and Leases | loan		2	3	13		11
Post-Modification Recorded Investment | $	[1]	$ 399	$ 264	$ 3,212		$ 923
Consumer Portfolio Segment [Member] | Home Equity Loan [Member] | Other [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans and Leases | loan	[2]	12	8	55		37
Post-Modification Recorded Investment | $	[1],[2]	$ 839	$ 270	$ 3,733		$ 1,447
Commercial Portfolio Segment [Member] | Commercial and Industrial Sector [Member] | Extended Maturity [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans and Leases | loan		0	2	8		11
Post-Modification Recorded Investment | $	[1]	$ 0	$ 213	$ 813		$ 14,862
Commercial Portfolio Segment [Member] | Commercial and Industrial Sector [Member] | Maturity/Rate Combined [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans and Leases | loan		8	0	13		2
Post-Modification Recorded Investment | $	[1]	$ 299	$ 0	$ 9,153		$ 648
Commercial Portfolio Segment [Member] | Commercial and Industrial Sector [Member] | Other [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans and Leases | loan	[2]	0	4	1		11
Post-Modification Recorded Investment | $	[1],[2]	$ 0	$ 1,265	$ 4		$ 1,639
Commercial Real Estate Portfolio Segment [Member] | Real Estate Loan [Member] | Extended Maturity [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans and Leases | loan		0	1	0		1
Post-Modification Recorded Investment | $		$ 0	$ 109	$ 0	[1]	$ 109	[1]
Commercial Real Estate Portfolio Segment [Member] | Real Estate Loan [Member] | Maturity/Rate Combined [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans and Leases | loan		0	1	0		2
Post-Modification Recorded Investment | $	[1]	$ 0	$ 291	$ 0		$ 335
Commercial Real Estate Portfolio Segment [Member] | Real Estate Loan [Member] | Other [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans and Leases | loan	[2]	0	0	0		1
Post-Modification Recorded Investment | $	[1],[2]	$ 0	$ 0	$ 0		$ 509
Finance Leases Portfolio Segment [Member] | Extended Maturity [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans and Leases | loan		0	6	0		7
Post-Modification Recorded Investment | $	[1]	$ 0	$ 6,638	$ 0		$ 6,642
[1]	ost-modification balances approximate pre-modification balances. The aggregate amount of charge-offs as a result of the restructurings was not significant.
[2]	ther includes covenant modifications, forbearance, loans discharged under Chapter 7 bankruptcy, or other concessions.

Loans and Leases (Information58

Loans and Leases (Information on Loans and Leases Modified as TDR within the Previous 12 Months with payment default) (Narrative) (Detail)	3 Months Ended		9 Months Ended
	Sep. 30, 2017USD ($)loan	Sep. 30, 2016USD ($)	Sep. 30, 2017USD ($)	Sep. 30, 2016USD ($)
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Subsequent Default, Recorded Investment		$ 0		$ 0
Residential Portfolio Segment [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans and Leases | loan	1
Financing Receivable, Modifications, Subsequent Default, Recorded Investment	$ 248,000		$ 248,000

Loans and Leases (Investments i

Loans and Leases (Investments in TDRs, Segregated by Risk Rating Exposure) (Detail) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Financing Receivable, Modifications [Line Items]
Total recorded investment of TDRs	$ 218,350	$ 223,528
Commerial, Commercial Real Estate, Equipment Financing TDR's [Member]
Financing Receivable, Modifications [Line Items]
Total recorded investment of TDRs	55,419	58,464
Commerial, Commercial Real Estate, Equipment Financing TDR's [Member] | (1) - (6) Pass [Member]
Financing Receivable, Modifications [Line Items]
Total recorded investment of TDRs	8,902	10,210
Commerial, Commercial Real Estate, Equipment Financing TDR's [Member] | (7) Special Mention [Member]
Financing Receivable, Modifications [Line Items]
Total recorded investment of TDRs	360	7
Commerial, Commercial Real Estate, Equipment Financing TDR's [Member] | (8) Substandard [Member]
Financing Receivable, Modifications [Line Items]
Total recorded investment of TDRs	46,157	45,509
Commerial, Commercial Real Estate, Equipment Financing TDR's [Member] | (9) Doubtful [Member]
Financing Receivable, Modifications [Line Items]
Total recorded investment of TDRs	$ 0	$ 2,738

Transfers of Financial Assets60

Transfers of Financial Assets (Reserve for loan repurchases) (Detail) - Reserve for Off-balance Sheet Activities [Member] - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Movement in Valuation Allowances and Reserves [Roll Forward]
Beginning balance	$ 843	$ 992	$ 790	$ 1,192
Provision (benefit) charged to expense	25	37	78	(64)
Repurchased loans and settlements charged off	(18)	0	(18)	(99)
Ending balance	$ 850	$ 1,029	$ 850	$ 1,029

Transfers of Financial Assets61

Transfers of Financial Assets (Loans sold) (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Net gain on sale	$ 2,421	$ 4,322	$ 8,038	$ 11,335
Residential Mortgage [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Proceeds from sale	88,691	128,268	262,029	298,840
Loans sold with servicing rights retained	79,690	115,822	239,357	273,827
Net gain on sale	1,979	3,324	4,356	6,749
Ancillary Fee Income Generated by Servicing Financial Assets, Amount	682	1,046	2,091	2,485
Fair value option adjustment	$ (240)	$ (48)	$ 1,591	$ 2,101

Transfers of Financial Assets62

Transfers of Financial Assets (Mortgage Servicing Assets) (Narrative) (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 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			$ 7,445	$ 20,764
Residential Mortgage [Member]
Securitization or Asset-backed Financing Arrangement, Financial Asset for which Transfer is Accounted as Sale [Line Items]
Retained servicing rights	$ 2,600,000	$ 2,600,000	2,600,000	2,600,000
Bank servicing fees	$ 200	$ 300	600	900
Proceeds from loans not originated for sale			$ 7,400
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				$ 20,800

Transfers of Financial Assets S

Transfers of Financial Assets Servicing Assets at Amortized Cost Roll Forward (Details) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Servicing Asset at Amortized Cost, Balance [Roll Forward]
Beginning Balance	$ 24,708	$ 21,946	$ 24,466	$ 20,698
Additions	2,576	3,338	7,063	8,198
Amortization	(2,144)	(1,900)	(6,389)	(5,512)
Ending Balance	$ 25,140	$ 23,384	$ 25,140	$ 23,384

Goodwill and Other Intangible64

Goodwill and Other Intangible Assets (Gross Carrying Value And Accumulated Amortization Of Other Intangible Assets) (Detail) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 43,000	$ 43,000
Accumulated Amortization	(12,411)	(9,326)
Net Carrying Amount	30,589	33,674
Goodwill	538,373	538,373
HSA Bank [Member]
Finite-Lived Intangible Assets [Line Items]
Goodwill	21,813	21,813
Community Banking [Member]
Finite-Lived Intangible Assets [Line Items]
Goodwill	516,560	516,560
Core Deposits [Member] | HSA Bank [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	22,000	22,000
Accumulated Amortization	(8,036)	(6,162)
Net Carrying Amount	13,964	15,838
Customer Relationships [Member] | HSA Bank [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	21,000	21,000
Accumulated Amortization	(4,375)	(3,164)
Net Carrying Amount	$ 16,625	$ 17,836

Goodwill and Other Intangible65

Goodwill and Other Intangible Assets (Schedule Of Expected Future Amortization Expense) (Detail) $ in Thousands	Sep. 30, 2017USD ($)
Goodwill and Intangible Assets Disclosure [Abstract]
Remainder of 2017	$ 978
2,018	3,847
2,019	3,847
2,020	3,847
2,021	3,847
Thereafter	$ 14,223

Deposits (Summary Of Deposits)

Deposits (Summary Of Deposits) (Detail) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Non-interest-bearing:
Demand	$ 4,138,206	$ 4,021,061
Interest-bearing:
Checking	2,581,266	2,528,274
Health savings accounts	4,891,024	4,362,503
Money market	2,598,187	2,047,121
Savings	4,428,061	4,320,090
Time deposits	2,218,491	2,024,808
Total interest-bearing	16,717,029	15,282,796
Total deposits	20,855,235	19,303,857
Time deposits and interest-bearing checking, included in above balances, obtained through brokers	913,042	848,618
Time deposits, included in above balance, that meet or exceed the FDIC limit	613,012	490,721
Deposit overdrafts reclassified as loan balances	$ 2,494	$ 1,885

Deposits (Scheduled Maturities

Deposits (Scheduled Maturities Of Time Deposits) (Detail) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Banking and Thrift [Abstract]
Remainder of 2017	$ 285,203
2,018	952,745
2,019	607,952
2,020	225,159
2,021	107,921
Thereafter	39,511
Total time deposits	$ 2,218,491	$ 2,024,808

Borrowings Borrowings - (Narrat

Borrowings Borrowings - (Narrative) (Details) - USD ($) $ in Billions	Sep. 30, 2017	Dec. 31, 2016
Debt Disclosure [Abstract]
Total borrowings	$ 2.6	$ 4

Borrowings (Summary Of Securiti

Borrowings (Summary Of Securities Sold Under Agreements To Repurchase And Other Borrowings) (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Assets Sold under Agreements to Repurchase [Line Items]
Securities sold under agreements to repurchase	$ 735,902	$ 740,526
Fed funds purchased	167,000	209,000
Securities sold under agreements to repurchase and other borrowings	$ 902,902	$ 949,526
Securities Sold under Agreements to Repurchase [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Short-term Debt, Weighted Average Interest Rate, at Point in Time	1.73%	1.82%
Federal Funds Purchased [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Short-term Debt, Weighted Average Interest Rate, at Point in Time	1.12%	0.46%
Federal Funds Purchased and Securities Sold under Agreements to Repurchase [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Short-term Debt, Weighted Average Interest Rate, at Point in Time	1.62%	1.53%
Original maturity of one year or less [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Securities sold under agreements to repurchase	$ 335,902	$ 340,526
Original maturity of one year or less [Member] | Securities Sold under Agreements to Repurchase [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Short-term Debt, Weighted Average Interest Rate, at Point in Time	0.18%	0.16%
Original maturity of greater than one year, non-callable [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Securities sold under agreements to repurchase	$ 400,000	$ 400,000
Original maturity of greater than one year, non-callable [Member] | Securities Sold under Agreements to Repurchase [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Short-term Debt, Weighted Average Interest Rate, at Point in Time	3.04%	3.09%

Borrowings (Federal Home Loan A

Borrowings (Federal Home Loan Advances) (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Federal Home Loan Bank, Advances, Maturity, Rolling Year [Abstract]
FHLB advances maturing within 1 year, Total Outstanding	$ 880,500	$ 2,130,500
FHLB advances maturing after 1 but within 2 years, Total Outstanding	133,731	200,000
FHLB advances maturing after 2 but within 3 years, Total Outstanding	259,295	128,026
FHLB advances maturing after 3 but within 4 years, Total Outstanding	75,000	175,000
FHLB advances maturing after 4 but within 5 years, Total Outstanding	150,061	200,000
FHLB advances maturing after 5 years, Total Outstanding	9,091	9,370
Federal Home Loan Bank, Advances	1,507,678	2,842,896
Premiums on advances	3	12
Federal Home Loan Bank advances	$ 1,507,681	$ 2,842,908
Federal Home Loan Bank, Advances, Weighted Average Interest Rate [Abstract]
FHLB advances maturing within 1 year, Weighted Average Contractual Coupon Rate (as a percent)	1.28%	0.71%
FHLB advances maturing after 1 but within 2 years, Weighted Average Contractual Coupon Rate (as a percent)	1.34%	1.36%
FHLB advances maturing after 2 but within 3 years, Weighted Average Contractual Coupon Rate (as a percent)	1.79%	1.73%
FHLB advances maturing after 3 but within 4 years, Weighted Average Contractual Coupon Rate (as a percent)	1.51%	1.77%
FHLB advances maturing after 4 but within 5 years, Weighted Average Contractual Coupon Rate (as a percent)	2.23%	1.81%
FHLB advances maturing after 5 years, Weighted Average Contractual Coupon Rate (as a percent)	2.61%	2.59%
Federal Home Loan Bank, Advances, Weighted Average Contractual Coupon Rate (as a percent)	1.49%	0.95%
Pledged Financial Instruments, Not Separately Reported, Loans Receivable, for Federal Home Loan Bank Debt	$ 6,388,102	$ 5,967,318
Remaining borrowing capacity	$ 2,668,964	$ 1,192,758

Borrowings (Long Term Debt) (De

Borrowings (Long Term Debt) (Details) - USD ($)		Sep. 30, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
Notes and subordinated debt		$ 227,320,000	$ 227,320,000
Debt issuance cost on senior fixed-rates		(860,000)	(961,000)
Long-term debt		$ 225,704,000	$ 225,514,000
Variable interest rate		4.27%	3.94%
London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument [Line Items]
Basis spread on variable rate		2.95%
Long-term Debt [Member]
Debt Instrument [Line Items]
Discount on senior fixed-rate notes		$ (756,000)	$ (845,000)
4.375% Senior fixed-rate notes due February 15, 2024 [Member]
Debt Instrument [Line Items]
Senior notes, interest rate (as a percent)		4.375%
Notes and subordinated debt		$ 150,000,000	150,000,000
Junior subordinated debt Webster Statutory Trust I floating-rate notes due September 17, 2033 [Member]
Debt Instrument [Line Items]
Notes and subordinated debt	[1]	$ 77,320,000	$ 77,320,000
[1]	The interest rate on Webster Statutory Trust I floating-rate notes, which varies quarterly based on 3-month LIBOR plus 2.95% , was 4.27% at September 30, 2017 and 3.94% at December 31, 2016

Accumulated Other Comprehensi72

Accumulated Other Comprehensive Loss, Net of Tax (Schedule of Other Comprehensive Income (Loss)) (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance			$ 2,527,012	$ 2,413,960
Other comprehensive income (loss), net of tax	$ 2,984	$ 4,358	7,895	24,953
Ending Balance	2,638,787	2,511,629	2,638,787	2,511,629
Available For Sale and Transferred Securities [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	(14,501)	12,363	(15,476)	(6,407)
OCI/OCL before reclassifications	872	1,218	1,847	20,156
Amounts reclassified from AOCL	0	0	0	(168)
Other comprehensive income (loss), net of tax	872	1,218	1,847	19,988
Ending Balance	(13,629)	13,581	(13,629)	13,581
Derivative Instruments [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	(15,258)	(23,406)	(17,068)	(22,980)
OCI/OCL before reclassifications	(34)	794	(445)	(2,416)
Amounts reclassified from AOCL	1,145	1,221	3,366	4,005
Other comprehensive income (loss), net of tax	1,111	2,015	2,921	1,589
Ending Balance	(14,147)	(21,391)	(14,147)	(21,391)
Defined Benefit Pension and Other Postretirement Benefit Plans [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	(42,323)	(46,468)	(44,449)	(48,719)
OCI/OCL before reclassifications	0	0	0	0
Amounts reclassified from AOCL	1,001	1,125	3,127	3,376
Other comprehensive income (loss), net of tax	1,001	1,125	3,127	3,376
Ending Balance	(41,322)	(45,343)	(41,322)	(45,343)
AOCI Attributable to Parent [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	(72,082)	(57,511)	(76,993)	(78,106)
OCI/OCL before reclassifications	838	2,012	1,402	17,740
Amounts reclassified from AOCL	2,146	2,346	6,493	7,213
Other comprehensive income (loss), net of tax	2,984	4,358	7,895	24,953
Ending Balance	$ (69,098)	$ (53,153)	$ (69,098)	$ (53,153)

Accumulated Other Comprehensi73

Accumulated Other Comprehensive Loss, Net of Tax (Schedule of Accumulated Other Comprehensive Loss) (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Impairment loss recognized in earnings	$ 0	$ 0	$ (126)	$ (149)
Income (loss) before income tax expense	94,777	76,262	266,868	221,945
Income tax expense	(30,281)	(24,445)	(81,322)	(72,478)
Earnings applicable to common shareholders	62,426	49,634	179,262	142,927
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]
Gain on sale of investment securities, net	0	0	0	414
Impairment loss recognized in earnings	0	0	0	(149)
Income (loss) before income tax expense	0	0	0	265
Accumulated Net Investment Gain (Loss) Attributable to Parent [Member]
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Net of tax	0	0	0	168
Accumulated Net Investment Gain (Loss) Attributable to Parent [Member] | Reclassification out of accumualted comprehensive income [Member]
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Income tax expense	0	0	0	(97)
Earnings applicable to common shareholders	0	0	0	168
Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member]
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Net of tax	(1,145)	(1,221)	(3,366)	(4,005)
Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member] | Reclassification out of accumualted comprehensive income [Member]
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Income tax expense	665	704	1,950	2,309
Earnings applicable to common shareholders	(1,145)	(1,221)	(3,366)	(4,005)
Total interest expense	(1,810)	(1,925)	(5,316)	(6,314)
Accumulated Defined Benefit Plans Adjustment, Net Unamortized Gain (Loss) [Member]
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Total before tax	(1,587)	(1,780)	(4,959)	(5,343)
Accumulated Defined Benefit Plans Adjustment, Net Prior Service Cost (Credit) [Member]
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Total before tax	0	(4)	0	(11)
Defined benefit pension and postretirement benefit plans [Member]
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Total before tax	(1,587)	(1,784)	(4,959)	(5,354)
Income tax expense	586	659	1,832	1,978
Net of tax	$ (1,001)	$ (1,125)	$ (3,127)	$ (3,376)

Regulatory Matters (Information

Regulatory Matters (Information On The Capital Ratios) (Detail) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Common Equity Tier One Capital	$ 2,031,955		$ 1,932,171
Common Equity Tier One Capital Ratio	10.99%		10.52%
Common Equity Tier One Capital Required for Capital Adequacy	$ 832,149		$ 826,504
Common Equity Tier One Capital Required to be Well-Capitalized	1,201,993		1,193,840
Total risk-based capital, Actual Amount	$ 2,436,332		$ 2,328,808
Total risk-based capital, Actual Ratio	13.17%		12.68%
Total risk-based capital, Capital Requirements, Minimum Amount	$ 1,479,376		$ 1,469,341
Total risk-based capital, Capital Requirements, Minimum Ratio	8.00%		8.00%
Total risk-based capital, Capital Requirements, Well Capitalized Amount	$ 1,849,220		$ 1,836,677
Total risk-based capital, Capital Requirements, Well Capitalized Ratio	10.00%		10.00%
Tier 1 capital, Actual Amount	$ 2,154,665		$ 2,054,881
Tier 1 capital, Actual Ratio	11.65%		11.19%
Tier 1 capital, Capital Requirements, Minimum Amount	$ 1,109,532		$ 1,102,006
Tier 1 capital, Capital Requirements, Minimum Ratio	6.00%		6.00%
Tier 1 capital, Capital Requirements, Well Capitalized Amount	$ 1,479,376		$ 1,469,341
Tier 1 capital, Capital Requirements, Well Capitalized Ratio	8.00%		8.00%
Tier 1 leverage capital ratio, Actual Amount	$ 2,154,665		$ 2,054,881
Tier 1 leverage capital ratio, Actual Ratio	8.36%		8.13%
Tier 1 leverage capital ratio, Capital Requirements, Minimum Amount	$ 1,030,973		$ 1,010,857
Tier 1 leverage capital ratio, Capital Requirements, Minimum Ratio	4.00%		4.00%
Tier 1 leverage capital ratio, Capital Requirements, Well Capitalized Amount	$ 1,288,717		$ 1,263,571
Tier 1 leverage capital ratio, Capital Requirements, Well Capitalized Ratio	5.00%		5.00%
Dividends paid	$ 80,000	$ 115,000
Subsidiaries [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Common Equity Tier One Capital	$ 2,061,764		$ 1,945,332
Common Equity Tier One Capital Ratio	11.16%		10.61%
Common Equity Tier One Capital Required for Capital Adequacy	$ 831,319		$ 825,228
Common Equity Tier One Capital Required to be Well-Capitalized	1,200,794		1,191,995
Total risk-based capital, Actual Amount	$ 2,266,110		$ 2,141,939
Total risk-based capital, Actual Ratio	12.27%		11.68%
Total risk-based capital, Capital Requirements, Minimum Amount	$ 1,477,900		$ 1,467,071
Total risk-based capital, Capital Requirements, Minimum Ratio	8.00%		8.00%
Total risk-based capital, Capital Requirements, Well Capitalized Amount	$ 1,847,376		$ 1,833,839
Total risk-based capital, Capital Requirements, Well Capitalized Ratio	10.00%		10.00%
Tier 1 capital, Actual Amount	$ 2,061,764		$ 1,945,332
Tier 1 capital, Actual Ratio	11.16%		10.61%
Tier 1 capital, Capital Requirements, Minimum Amount	$ 1,108,425		$ 1,100,304
Tier 1 capital, Capital Requirements, Minimum Ratio	6.00%		6.00%
Tier 1 capital, Capital Requirements, Well Capitalized Amount	$ 1,477,900		$ 1,467,071
Tier 1 capital, Capital Requirements, Well Capitalized Ratio	8.00%		8.00%
Tier 1 leverage capital ratio, Actual Amount	$ 2,061,764		$ 1,945,332
Tier 1 leverage capital ratio, Actual Ratio	8.00%		7.70%
Tier 1 leverage capital ratio, Capital Requirements, Minimum Amount	$ 1,030,260		$ 1,010,005
Tier 1 leverage capital ratio, Capital Requirements, Minimum Ratio	4.00%		4.00%
Tier 1 leverage capital ratio, Capital Requirements, Well Capitalized Amount	$ 1,287,825		$ 1,262,507
Tier 1 leverage capital ratio, Capital Requirements, Well Capitalized Ratio	5.00%		5.00%
Cash Pass-through Reserve, Federal Home Loan Bank	$ 76,700		$ 58,600
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%

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		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Earnings for basic and diluted earnings per common share:
Net income	$ 64,496	$ 51,817	$ 185,546	$ 149,467
Less: Preferred stock dividends	2,024	2,024	6,072	6,072
Undistributed Earnings, Basic	62,472	49,793	179,474	143,395
Net income available to common shareholders	62,472	49,793	179,474	143,395
Less: Earnings applicable to participating securities	46	159	212	468
Less: Earnings applicable to participating securities	46	159	212	468
Earnings applicable to common shareholders	62,426	49,634	179,262	142,927
Earnings applicable to common shareholders	$ 62,426	$ 49,634	$ 179,262	$ 142,927
Shares:
Weighted average common shares outstanding - basic (in shares)	92,125	91,365	92,003	91,298
Effect of dilutive securities:
Stock options and restricted stock (in shares)	372	465	403	452
Warrants (in shares)	6	27	6	26
Weighted-average common shares outstanding - diluted (in shares)	92,503	91,857	92,412	91,776
Earnings per common share:
Basic (in dollars per share)	$ 0.68	$ 0.54	$ 1.95	$ 1.57
Diluted (in dollars per share)	$ 0.67	$ 0.54	$ 1.94	$ 1.56

Earnings Per Common Share Sched

Earnings Per Common Share Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share (Details) - shares shares in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Stock options (shares with exercise price greater than market price) [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	0	172	0	172
Restricted stock (due to performance conditions on non-participating shares) [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	80	0	61	161

Derivative Financial Instrume77

Derivative Financial Instruments (Schedule fair value of derivative instruments) (Detail) - USD ($) $ in Thousands		Sep. 30, 2017	Dec. 31, 2016
Derivatives, Fair Value [Line Items]
Derivative instrument assets, Gross Amount		$ 6,424	$ 35,727
Asset Derivatives, Fair Value, Less: Cash collateral posted		30,500
Derivative Asset		969	0
Liability Derivatives, Fair Value, Gross Liability		3,838	25,300
Liability Derivatives, Fair Value, Less: Cash collateral posted		9,800
Derivative liability		156	446
Subject to and not subject to Master Netting Agreements [Member]
Derivatives, Fair Value [Line Items]
Asset Derivatives, Notional Amounts		4,379,221	4,104,713
Derivative Asset, Fair Value, Gross Asset Including Not Subject to Master Netting Arrangement		42,250	77,637
Asset Derivatives, Fair Value, Less: Legally enforceable master netting agreements		2,915	24,252
Asset Derivatives, Fair Value, Less: Cash collateral posted		2,540	11,475
Derivative Asset		36,795	41,910
Liability Derivatives, Notional Amount		3,062,131	2,956,313
Derivative Liability, Fair Value, Gross Liability Including Not Subject to Master Netting Arrangement		20,023	45,189
Liability Derivatives, Fair Value, Less: Legally enforceable master netting agreements		2,916	24,254
Liability Derivatives, Fair Value, Less: Cash collateral posted		766	600
Derivative liability		16,341	20,335
Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative instrument assets, Gross Amount		1,972	3,270
Asset Derivatives, Fair Value, Less: Legally enforceable master netting agreements		292	2,335
Asset Derivatives, Fair Value, Less: Cash collateral posted		1,051	935
Derivative Asset		629	0
Liability Derivatives, Fair Value, Gross Liability		195	792
Liability Derivatives, Fair Value, Less: Legally enforceable master netting agreements		195	792
Liability Derivatives, Fair Value, Less: Cash collateral posted		0	0
Derivative liability		0	0
Designated as Hedging Instrument [Member] | Derivatives Subject to Master Netting Arrangement or Similar Arrangement [Member] | Interest rate derivatives [Member]
Derivatives, Fair Value [Line Items]
Asset Derivatives, Notional Amounts	[1]	225,000	225,000
Derivative instrument assets, Gross Amount	[1]	1,972	3,270
Liability Derivatives, Notional Amount	[1]	100,000	100,000
Liability Derivatives, Fair Value, Gross Liability	[1]	195	792
Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative instrument assets, Gross Amount		4,452	32,457
Asset Derivatives, Fair Value, Less: Legally enforceable master netting agreements		2,623	21,917
Asset Derivatives, Fair Value, Less: Cash collateral posted		1,489	10,540
Derivative Asset		340	0
Liability Derivatives, Fair Value, Gross Liability		3,643	24,508
Liability Derivatives, Fair Value, Less: Legally enforceable master netting agreements		2,721	23,462
Liability Derivatives, Fair Value, Less: Cash collateral posted		766	600
Derivative liability		156	446
Not Designated as Hedging Instrument [Member] | Derivatives Subject to Master Netting Arrangement or Similar Arrangement [Member] | Interest rate derivatives [Member]
Derivatives, Fair Value [Line Items]
Asset Derivatives, Notional Amounts	[1]	2,270,444	1,943,485
Derivative instrument assets, Gross Amount	[1]	4,225	32,226
Liability Derivatives, Notional Amount	[1]	1,125,953	1,242,937
Liability Derivatives, Fair Value, Gross Liability	[1]	3,224	24,388
Not Designated as Hedging Instrument [Member] | Derivatives Subject to Master Netting Arrangement or Similar Arrangement [Member] | Other [Member]
Derivatives, Fair Value [Line Items]
Asset Derivatives, Notional Amounts	[1]	8,595	10,634
Derivative instrument assets, Gross Amount	[1]	260	231
Liability Derivatives, Notional Amount	[1]	22,161	14,265
Liability Derivatives, Fair Value, Gross Liability	[1]	419	120
Not Designated as Hedging Instrument [Member] | Derivatives Not Subject to Master Netting Arrangement or Similar Arrangement [Member]
Derivatives, Fair Value [Line Items]
Asset Derivatives, Notional Amounts		4,154,221	3,879,713
Asset Derivatives, Fair Value, Positions not subject to master netting agreement		40,278	74,367
Liability Derivatives, Notional Amount		2,962,131	2,856,313
Liability Derivatives, Fair Value, Positions not subject to master netting agreement		19,828	44,397
Not Designated as Hedging Instrument [Member] | Derivatives Not Subject to Master Netting Arrangement or Similar Arrangement [Member] | Interest rate derivatives [Member]
Derivatives, Fair Value [Line Items]
Asset Derivatives, Notional Amounts		1,738,527	1,734,679
Asset Derivatives, Fair Value, Positions not subject to master netting agreement		35,065	38,668
Liability Derivatives, Notional Amount		1,652,004	1,451,762
Liability Derivatives, Fair Value, Positions not subject to master netting agreement		15,764	19,001
Not Designated as Hedging Instrument [Member] | Derivatives Not Subject to Master Netting Arrangement or Similar Arrangement [Member] | RPAs [Member] | RPA-Out [Member]
Derivatives, Fair Value [Line Items]
Asset Derivatives, Notional Amounts		94,103	86,037
Asset Derivatives, Fair Value, Positions not subject to master netting agreement		112	139
Not Designated as Hedging Instrument [Member] | Derivatives Not Subject to Master Netting Arrangement or Similar Arrangement [Member] | RPAs [Member] | RPA-In [Member]
Derivatives, Fair Value [Line Items]
Liability Derivatives, Notional Amount		99,538	87,273
Liability Derivatives, Fair Value, Positions not subject to master netting agreement		136	166
Not Designated as Hedging Instrument [Member] | Derivatives Not Subject to Master Netting Arrangement or Similar Arrangement [Member] | Mortgage Banking Derivatives [Member] | RPA-Out [Member]
Derivatives, Fair Value [Line Items]
Asset Derivatives, Notional Amounts		42,290	103,440
Asset Derivatives, Fair Value, Positions not subject to master netting agreement		614	3,084
Not Designated as Hedging Instrument [Member] | Derivatives Not Subject to Master Netting Arrangement or Similar Arrangement [Member] | Mortgage Banking Derivatives [Member] | RPA-In [Member]
Derivatives, Fair Value [Line Items]
Liability Derivatives, Notional Amount		60,698	59,895
Liability Derivatives, Fair Value, Positions not subject to master netting agreement		128	711
Not Designated as Hedging Instrument [Member] | Derivatives Not Subject to Master Netting Arrangement or Similar Arrangement [Member] | Other [Member]
Derivatives, Fair Value [Line Items]
Asset Derivatives, Notional Amounts		262	1,438
Asset Derivatives, Fair Value, Positions not subject to master netting agreement		2	19
Liability Derivatives, Notional Amount		1,777	181
Liability Derivatives, Fair Value, Positions not subject to master netting agreement		157	$ 11
Loan Origination Commitments [Member]
Derivatives, Fair Value [Line Items]
Other Commitment		60,500
Interest Rate Lock Commitments [Member]
Derivatives, Fair Value [Line Items]
Other Commitment		$ 21,900
[1]	One of Webster's counterparty relationships was impacted by a Chicago Mercantile Exchange rulebook amendment, resulting in the presentation of that relationship on a settlement basis, as a single unit of account at September 30, 2017

Derivative Financial Instrume78

Derivative Financial Instruments (Schedule of the changes in the fair value of non-hedge accounting derivatives) (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) on Fair Value Hedges Recognized in Earnings	$ 1,326	$ 1,153	$ (583)	$ 6,147
Interest Rate Derivatives [Member] | Operating Expense [Member] | Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) on Fair Value Hedges Recognized in Earnings	1,501	608	1,780	6,515
RPA [Member] | Operating Expense [Member] | Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) on Fair Value Hedges Recognized in Earnings	51	110	157	(143)
Mortgage Banking Derivatives [Member] | Operating Expense [Member] | Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) on Fair Value Hedges Recognized in Earnings	(219)	720	(1,886)	357
Other [Member] | Operating Expense [Member] | Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) on Fair Value Hedges Recognized in Earnings	$ (7)	$ (285)	$ (634)	$ (582)

Derivative Financial Instrume79

Derivative Financial Instruments (AOCI Related to Cash Flow Hedges) (Narrative) (Detail) - Cash Flow Hedging [Member] $ in Millions	9 Months Ended
	Sep. 30, 2017USD ($)
Derivative Instruments, Gain (Loss) [Line Items]
Estimate of amount to be reclassified from AOCL	$ (6.4)
Remaining unamortized gain (loss) on termination of cash flow hedges	(16.5)
Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Estimate of amount to be reclassified from AOCL	$ 1.2

Derivative Financial Instrume80

Derivative Financial Instruments (Offsetting Derivatives) (Detail) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Derivative [Line Items]
Derivative instrument assets, Gross Amount	$ 6,424	$ 35,727
Derivative instrument asset, Amount Offset	30,500
Derivative Asset	969	0
Liability Derivatives, Fair Value, Gross Liability	3,838	25,300
Derivative Liability, Collateral, Right to Reclaim Cash, Offset	(9,800)
Derivative liability	156	446
Hedge Accounting Positions [Member]
Derivative [Line Items]
Derivative instrument assets, Gross Amount	1,972	3,270
Derivative instrument asset, Amount Offset, Total	(292)	(2,335)
Derivative instrument asset, Amount Offset	1,051	935
Derivative Asset	629	0
Liability Derivatives, Fair Value, Gross Liability	195	792
Derivative instrument liability, Amount Offset, Total	(195)	(792)
Derivative Liability, Collateral, Right to Reclaim Cash, Offset	0	0
Derivative liability	0	0
Non-Hedged Accounting Positions [Member]
Derivative [Line Items]
Derivative instrument assets, Gross Amount	4,452	32,457
Derivative instrument asset, Amount Offset, Total	(2,623)	(21,917)
Derivative instrument asset, Amount Offset	1,489	10,540
Derivative Asset	340	0
Liability Derivatives, Fair Value, Gross Liability	3,643	24,508
Derivative instrument liability, Amount Offset, Total	(2,721)	(23,462)
Derivative Liability, Collateral, Right to Reclaim Cash, Offset	(766)	(600)
Derivative liability	156	446
Subject to and not subject to Master Netting Agreements [Member]
Derivative [Line Items]
Derivative instrument asset, Amount Offset, Total	(2,915)	(24,252)
Derivative instrument asset, Amount Offset	2,540	11,475
Derivative Asset	36,795	41,910
Derivative instrument liability, Amount Offset, Total	(2,916)	(24,254)
Derivative Liability, Collateral, Right to Reclaim Cash, Offset	(766)	(600)
Derivative liability	$ 16,341	$ 20,335

Derivative Financial Instrume81

Derivative Financial Instruments (Counterparty Credit Risk Narrative) (Detail) $ in Millions	Sep. 30, 2017USD ($)
Derivative [Line Items]
Derivative, Collateral, Right to Reclaim Cash	$ 20.7
Derivative instrument asset, Amount Offset	30.5
Derivative Liability, Collateral, Right to Reclaim Cash, Offset	(9.8)
Credit Derivative, Maximum Exposure, Undiscounted	35.1
Market Approach Valuation Technique [Member]
Derivative [Line Items]
Credit Derivative, Maximum Exposure, Undiscounted	$ 27.7

Fair Value Measurements (Narrat

Fair Value Measurements (Narrative) (Detail) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total credit-related financial instruments with off-balance sheet risk	$ 5,244,643	$ 5,399,762
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	5,300
Rabbi Trust [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other assets	2,900
Alternative investments [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other assets	17,300
Total credit-related financial instruments with off-balance sheet risk	$ 9,400

Fair Value Measurements (Fair V

Fair Value Measurements (Fair Value Assets And Liabilities Measured On Recurring Basis) (Detail) - USD ($) $ in Thousands		Sep. 30, 2017	Dec. 31, 2016
Financial assets held at fair value:
Derivative Asset		$ 969	$ 0
Originated loans held for sale		32,855	60,260
Financial liabilities held at fair value:
Derivative liability		156	446
Alternative investments [Member]
Financial assets held at fair value:
Other assets		17,300
Fair Value, Measurements, Recurring [Member]
Financial assets held at fair value:
Total financial assets held at fair value		2,678,531	3,139,609
Financial liabilities held at fair value:
Derivative liability	[1]	20,023	45,189
Fair Value, Measurements, Recurring [Member] | Derivative instruments [Member]
Financial assets held at fair value:
Derivative Asset	[1]	42,250	77,637
Fair Value, Measurements, Recurring [Member] | Available-for-sale Investment Securities [Member]
Financial assets held at fair value:
Available for sale investment securities		2,591,162	2,991,091
Fair Value, Measurements, Recurring [Member] | US Treasury Bill Securities [Member]
Financial assets held at fair value:
Available for sale investment securities		3,596	734
Fair Value, Measurements, Recurring [Member] | Agency CMO [Member]
Financial assets held at fair value:
Available for sale investment securities		331,798	419,706
Fair Value, Measurements, Recurring [Member] | Agency MBS [Member]
Financial assets held at fair value:
Available for sale investment securities		912,977	954,349
Fair Value, Measurements, Recurring [Member] | Agency CMBS [Member]
Financial assets held at fair value:
Available for sale investment securities		584,960	573,272
Fair Value, Measurements, Recurring [Member] | CMBS [Member]
Financial assets held at fair value:
Available for sale investment securities		403,433	477,365
Fair Value, Measurements, Recurring [Member] | CLO [Member]
Financial assets held at fair value:
Available for sale investment securities		274,583	427,390
Fair Value, Measurements, Recurring [Member] | Single issuer trust preferred securities [Member]
Financial assets held at fair value:
Available for sale investment securities		30,937	28,633
Fair Value, Measurements, Recurring [Member] | Corporate debt securities [Member]
Financial assets held at fair value:
Available for sale investment securities		48,878	109,642
Fair Value, Measurements, Recurring [Member] | Investments held In Rabbi Trust [Member]
Financial assets held at fair value:
Other assets		5,278	5,119
Fair Value, Measurements, Recurring [Member] | Alternative investments [Member]
Financial assets held at fair value:
Other assets		6,986	5,502
Fair Value, Measurements, Recurring [Member] | Loan Origination Commitments [Member]
Financial assets held at fair value:
Originated loans held for sale		32,855	60,260
Fair Value, Measurements, Recurring [Member] | Quoted Prices in Active Markets For Identical Assets (Level 1) [Member]
Financial assets held at fair value:
Total financial assets held at fair value		9,136	6,103
Financial liabilities held at fair value:
Derivative liability	[1]	562	120
Fair Value, Measurements, Recurring [Member] | Quoted Prices in Active Markets For Identical Assets (Level 1) [Member] | Derivative instruments [Member]
Financial assets held at fair value:
Derivative Asset	[1]	262	250
Fair Value, Measurements, Recurring [Member] | Quoted Prices in Active Markets For Identical Assets (Level 1) [Member] | Available-for-sale Investment Securities [Member]
Financial assets held at fair value:
Available for sale investment securities		3,596	734
Fair Value, Measurements, Recurring [Member] | Quoted Prices in Active Markets For Identical Assets (Level 1) [Member] | US Treasury Bill Securities [Member]
Financial assets held at fair value:
Available for sale investment securities		3,596	734
Fair Value, Measurements, Recurring [Member] | Quoted Prices in Active Markets For Identical Assets (Level 1) [Member] | Agency CMBS [Member]
Financial assets held at fair value:
Available for sale investment securities		0	0
Fair Value, Measurements, Recurring [Member] | Quoted Prices in Active Markets For Identical Assets (Level 1) [Member] | CMBS [Member]
Financial assets held at fair value:
Available for sale investment securities		0	0
Fair Value, Measurements, Recurring [Member] | Quoted Prices in Active Markets For Identical Assets (Level 1) [Member] | Investments held In Rabbi Trust [Member]
Financial assets held at fair value:
Other assets		5,278	5,119
Fair Value, Measurements, Recurring [Member] | Quoted Prices in Active Markets For Identical Assets (Level 1) [Member] | Alternative investments [Member]
Financial assets held at fair value:
Other assets		0	0
Fair Value, Measurements, Recurring [Member] | Quoted Prices in Active Markets For Identical Assets (Level 1) [Member] | Loan Origination Commitments [Member]
Financial assets held at fair value:
Originated loans held for sale		0	0
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member]
Financial assets held at fair value:
Total financial assets held at fair value		2,662,409	3,128,004
Financial liabilities held at fair value:
Derivative liability	[1]	19,461	45,069
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Derivative instruments [Member]
Financial assets held at fair value:
Derivative Asset	[1]	41,988	77,387
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Available-for-sale Investment Securities [Member]
Financial assets held at fair value:
Available for sale investment securities		2,587,566	2,990,357
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Agency CMO [Member]
Financial assets held at fair value:
Available for sale investment securities		331,798	419,706
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Agency MBS [Member]
Financial assets held at fair value:
Available for sale investment securities		912,977	954,349
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Agency CMBS [Member]
Financial assets held at fair value:
Available for sale investment securities		584,960	573,272
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | CMBS [Member]
Financial assets held at fair value:
Available for sale investment securities		403,433	477,365
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | CLO [Member]
Financial assets held at fair value:
Available for sale investment securities		274,583	427,390
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Single issuer trust preferred securities [Member]
Financial assets held at fair value:
Available for sale investment securities		30,937	28,633
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Corporate debt securities [Member]
Financial assets held at fair value:
Available for sale investment securities		48,878	109,642
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Alternative investments [Member]
Financial assets held at fair value:
Other assets		0	0
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Loan Origination Commitments [Member]
Financial assets held at fair value:
Originated loans held for sale		32,855	60,260
Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member]
Financial assets held at fair value:
Total financial assets held at fair value		6,986	5,502
Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Derivative instruments [Member]
Financial assets held at fair value:
Derivative Asset	[1]		0
Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Agency CMBS [Member]
Financial assets held at fair value:
Available for sale investment securities		0	0
Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | CMBS [Member]
Financial assets held at fair value:
Available for sale investment securities		0	0
Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Alternative investments [Member]
Financial assets held at fair value:
Other assets		$ 6,986	$ 5,502
[1]	or 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 12: Derivative Financial Instruments

Fair Value Measurements (Schedu

Fair Value Measurements (Schedule Of Changes In Level 3 Assets And Liabilities Measured At Fair Value On A Recurring Basis) (Detail) - Equity Method Investments [Member] $ in Thousands	9 Months Ended
	Sep. 30, 2017USD ($)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Level 3, beginning of period, Financial Assets	$ 5,502
Unrealized gain included in net income	639
Purchases/capital funding	899
Payments	(54)
Level 3, end of period, Financial Assets	$ 6,986

Fair Value Measurements (Sche85

Fair Value Measurements (Schedule Of Valuation Methodology And Unobservable Inputs) (Detail) - Significant Unobservable Inputs (Level 3) [Member] - Fair Value, Measurements, Nonrecurring [Member] $ in Thousands	9 Months Ended
	Sep. 30, 2017USD ($)
Fair Value Inputs, Assets, Quantitative Information [Line Items]
OREO	$ 2,587
Impaired Loans and Leases [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Collateral dependent impaired loans and leases	$ 15,955
Impaired Loans and Leases [Member] | Market Approach Valuation Technique [Member] | Minimum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Discount rate (as a percent)	0.00%
Impaired Loans and Leases [Member] | Market Approach Valuation Technique [Member] | Maximum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Discount rate (as a percent)	20.00%
Impaired Loans and Leases [Member] | Market Approach Valuation Technique - Discount for cost to sell [Member] | Minimum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Discount rate (as a percent)	0.00%
Impaired Loans and Leases [Member] | Market Approach Valuation Technique - Discount for cost to sell [Member] | Maximum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Discount rate (as a percent)	15.00%
Other Real Estate Owned [Member] | Market Approach Valuation Technique [Member] | Minimum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Discount rate (as a percent)	0.00%
Other Real Estate Owned [Member] | Market Approach Valuation Technique [Member] | Maximum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Discount rate (as a percent)	20.00%
Other Real Estate Owned [Member] | Market Approach Valuation Technique - Discount for cost to sell [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Discount rate (as a percent)	8.00%

Fair Value Measurements (Summar

Fair Value Measurements (Summary Of Estimated Fair Values Of Significant Financial Instruments) (Detail) - USD ($) $ in Thousands		Sep. 30, 2017	Jun. 30, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Dec. 31, 2015
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans held for sale		$ 32,855		$ 60,260
Mortgage servicing assets, Carrying Amount		25,140	$ 24,708	24,466	$ 23,384	$ 21,946	$ 20,698
Alternative investments [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Alternative investments		17,300
Fair Value, Measurements, Nonrecurring [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Alternative investments		2,587
Fair Value, Measurements, Nonrecurring [Member] | Reported Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans held for sale		0		7,317
Loans and leases, net		17,244,618		16,832,268
Securities sold under agreements to repurchase and other borrowings		902,902		949,526
FHLB advances	[1]	1,507,681		2,842,908
Long-term debt	[1]	225,704		225,514
Fair Value, Measurements, Nonrecurring [Member] | Reported Value Measurement [Member] | Deposits Liabilities, other than time deposits [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Deposits		18,636,744		17,279,049
Fair Value, Measurements, Nonrecurring [Member] | Reported Value Measurement [Member] | Time Deposits [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Deposits		2,218,491		2,024,808
Fair Value, Measurements, Nonrecurring [Member] | Reported Value Measurement [Member] | Alternative investments [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Alternative investments		10,296		11,034
Fair Value, Measurements, Nonrecurring [Member] | Reported Value Measurement [Member] | Residential Mortgage [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Mortgage servicing assets, Carrying Amount		25,140		24,466
Fair Value, Measurements, Nonrecurring [Member] | Reported Value Measurement [Member] | Held-to-maturity Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity investment securities		4,497,311		4,160,658
Fair Value, Measurements, Nonrecurring [Member] | Estimate of Fair Value Measurement [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans held for sale		0		7,444
Securities sold under agreements to repurchase and other borrowings		905,249		955,660
FHLB advances	[1]	1,512,203		2,825,101
Long-term debt	[1]	235,686		225,514
Fair Value, Measurements, Nonrecurring [Member] | Estimate of Fair Value Measurement [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans and leases, net		17,155,002		16,678,106
Fair Value, Measurements, Nonrecurring [Member] | Estimate of Fair Value Measurement [Member] | Deposits Liabilities, other than time deposits [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Deposits		18,636,744		17,279,049
Fair Value, Measurements, Nonrecurring [Member] | Estimate of Fair Value Measurement [Member] | Time Deposits [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Deposits		2,213,155		2,024,395
Fair Value, Measurements, Nonrecurring [Member] | Estimate of Fair Value Measurement [Member] | Alternative investments [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Alternative investments		12,539		13,189
Fair Value, Measurements, Nonrecurring [Member] | Estimate of Fair Value Measurement [Member] | Residential Mortgage [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Mortgage servicing assets, Fair value		44,992		52,075
Fair Value, Measurements, Nonrecurring [Member] | Estimate of Fair Value Measurement [Member] | Held-to-maturity Securities [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity investment securities		$ 4,481,675		$ 4,125,125
[1]	he following adjustments to the carrying amount are not included for determination of fair value, see Note 8: Borrowings : • FHLB advances - unamortized premiums on advances •

Retirement Benefit Plans (Detai

Retirement Benefit Plans (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 12	$ 11	$ 37	$ 34
Interest cost on benefit obligations	1,829	2,110	5,486	6,331
Expected return on plan assets	(3,074)	(3,067)	(9,222)	(8,596)
Amortization of prior service cost	0	0	0	0
Recognized net loss	1,466	1,666	4,398	4,998
Net periodic benefit cost	233	720	699	2,767
Supplemental Employee Retirement Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	0	0	0	0
Interest cost on benefit obligations	96	98	281	292
Expected return on plan assets	0	0	0	0
Amortization of prior service cost	0	0	0	0
Recognized net loss	136	106	561	319
Net periodic benefit cost	232	204	842	611
Other Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	0	0	0	0
Interest cost on benefit obligations	19	32	69	94
Expected return on plan assets	0	0	0	0
Amortization of prior service cost	0	4	0	11
Recognized net loss	(15)	8	0	26
Net periodic benefit cost	$ 4	$ 44	$ 69	$ 131

Share-Based Plans (Summary of S

Share-Based Plans (Summary of Stock-based compensation expense recognized) (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock compensation expense	$ 3,007	$ 2,944	$ 9,050	$ 8,558
Employee Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock compensation expense	0	0	0	43
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock compensation expense	$ 3,007	$ 2,944	$ 9,050	$ 8,515

Share-Based Plans (Narrative) (

Share-Based Plans (Narrative) (Detail) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2017	Dec. 31, 2016
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized stock compensation expense	$ 16.7
Weighted average recognition period	2 years
Restricted Stock [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of 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)	5 years
Performance-Based Restricted Stock Awards Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period (in years)	3 years
Vesting range (as a percent)	50.00%
Performance-Based Restricted Stock Awards Shares [Member] | Minimum [Member] | Share-based Compensation Award, Tranche Two [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting range (as a percent)	0.00%
Performance-Based Restricted Stock Awards Shares [Member] | Maximum [Member] | Share-based Compensation Award, Tranche One [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting range (as a percent)	150.00%
Employee Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of options outstanding (in shares)	793,630	1,072,974
Employee Stock Option [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Terms of Award (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)	735,785
Incentive Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of options outstanding (in shares)	57,845

Share-Based Plans (Summary of R

Share-Based Plans (Summary of Restricted Stock and Stock Option Activity) (Detail)	9 Months Ended
	Sep. 30, 2017$ / sharesshares
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Options exercisable, Number of Shares	793,630
Restricted Stock Awards [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)	253,361
Restricted stock, Granted (in shares)	164,953
Restricted stock, Vested restricted stock awards (in shares)	155,390	[1]
Restricted stock, Forfeited (in shares)	14,586
Restricted stock, Outstanding at end of period (in shares)	248,338
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	$ 32.24
Restricted stock, Granted (in dollars per share) | $ / shares	54.79
Restricted stock, Vested restricted stock awards (in dollars per share) | $ / shares	36.36	[1]
Restricted stock, Forfeited (in dollars per share) | $ / shares	36.44
Restricted stock, at end of period, Weighted-average Grant Date Fair Value (in dollars per share) | $ / shares	$ 43.96
Restricted Stock Units (RSUs) [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)	2,158
Restricted stock, Granted (in shares)	8,129
Restricted stock, Vested restricted stock awards (in shares)	6,900	[1]
Restricted stock, Forfeited (in shares)	0
Restricted stock, Outstanding at end of period (in shares)	3,387
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	$ 32.89
Restricted stock, Granted (in dollars per share) | $ / shares	56.07
Restricted stock, Vested restricted stock awards (in dollars per share) | $ / shares	48.82	[1]
Restricted stock, Forfeited (in dollars per share) | $ / shares	0
Restricted stock, at end of period, Weighted-average Grant Date Fair Value (in dollars per share) | $ / shares	$ 56.07
Performance-Based Restricted Stock Awards 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)	116,184
Restricted stock, Granted (in shares)	89,581
Restricted stock, Vested restricted stock awards (in shares)	87,982	[1]
Restricted stock, Forfeited (in shares)	6,276
Restricted stock, Outstanding at end of period (in shares)	111,507
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	$ 33.62
Restricted stock, Granted (in dollars per share) | $ / shares	56.18
Restricted stock, Vested restricted stock awards (in dollars per share) | $ / shares	40.74	[1]
Restricted stock, Forfeited (in dollars per share) | $ / shares	42.72
Restricted stock, at end of period, Weighted-average Grant Date Fair Value (in dollars per share) | $ / shares	$ 45.61
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	1,072,974
Options granted, Number of Shares	0
Exercised options, Number of Shares	279,344
Options forfeited, Number of Shares	0
Options outstanding, at end of period, Number of Shares	793,630
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	$ 21.24
Options granted, Weighted-Average Exercise Price (in dollars per share) | $ / shares	0
Exercised options, Weighted-Average Exercise Price (in dollars per share) | $ / shares	25.80
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	$ 19.63
[1]	ested for purposes of recording compensation expense.

Segment Reporting (Operating Re

Segment Reporting (Operating Results and Total Assets Reportable Segments) (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Segment Reporting Information [Line Items]
Total Assets	$ 26,350,182		$ 26,350,182		$ 26,072,529
Net interest income (expense)	200,904	$ 180,197	591,355	$ 533,254
Provision for Loan and Lease Losses	10,150	14,250	27,900	43,850
Net interest income after provision for loan and lease losses	190,754	165,947	563,455	489,404
Noninterest Income	65,846	66,412	193,439	193,861
Total non-interest expense	161,823	156,097	490,026	461,320
Income (loss) before income tax expense	94,777	76,262	266,868	221,945
Income tax expense	30,281	24,445	81,322	72,478
Net income	64,496	51,817	185,546	149,467
Operating Segments [Member] | Commercial Banking [Member]
Segment Reporting Information [Line Items]
Total Assets	9,428,676		9,428,676		9,069,445
Net interest income (expense)	81,925	74,265	239,118	211,422
Provision for Loan and Lease Losses	12,073	7,876	29,562	29,765
Net interest income after provision for loan and lease losses	69,852	66,389	209,556	181,657
Noninterest Income	13,207	15,916	39,163	41,819
Total non-interest expense	38,339	35,793	113,767	103,336
Income (loss) before income tax expense	44,720	46,512	134,952	120,140
Income tax expense	14,363	14,957	41,125	39,233
Net income	30,357	31,555	93,827	80,907
Operating Segments [Member] | Community Banking [Member]
Segment Reporting Information [Line Items]
Total Assets	8,881,322		8,881,322		8,721,046
Net interest income (expense)	96,859	91,995	286,351	274,186
Provision for Loan and Lease Losses	(1,923)	6,374	(1,662)	14,085
Net interest income after provision for loan and lease losses	98,782	85,621	288,013	260,101
Noninterest Income	27,079	29,130	80,516	83,248
Total non-interest expense	92,478	92,508	281,979	276,045
Income (loss) before income tax expense	33,383	22,243	86,550	67,304
Income tax expense	10,605	7,122	26,374	21,979
Net income	22,778	15,121	60,176	45,325
Operating Segments [Member] | HSA Bank [Member]
Segment Reporting Information [Line Items]
Total Assets	76,090		76,090		83,987
Net interest income (expense)	26,713	20,560	76,339	60,484
Provision for Loan and Lease Losses	0	0	0	0
Net interest income after provision for loan and lease losses	26,713	20,560	76,339	60,484
Noninterest Income	19,371	16,900	58,392	54,969
Total non-interest expense	27,222	23,021	84,211	71,966
Income (loss) before income tax expense	18,862	14,439	50,520	43,487
Income tax expense	6,006	4,624	15,395	14,201
Net income	12,856	9,815	35,125	29,286
Corporate, Non-Segment [Member]
Segment Reporting Information [Line Items]
Total Assets	7,964,094		7,964,094		$ 8,198,051
Net interest income (expense)	(4,593)	(6,623)	(10,453)	(12,838)
Provision for Loan and Lease Losses	0	0	0	0
Net interest income after provision for loan and lease losses	(4,593)	(6,623)	(10,453)	(12,838)
Noninterest Income	6,189	4,466	15,368	13,825
Total non-interest expense	3,784	4,775	10,069	9,973
Income (loss) before income tax expense	(2,188)	(6,932)	(5,154)	(8,986)
Income tax expense	(693)	(2,258)	(1,572)	(2,935)
Net income	$ (1,495)	$ (4,674)	$ (3,582)	$ (6,051)

Segment Reporting Segment Repor

Segment Reporting Segment Reporting Narrative (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2017USD ($)Segment	Dec. 31, 2016USD ($)	Sep. 30, 2016USD ($)
Segment Reporting Information [Line Items]
Number of Reportable Segments | Segment	3
Loans and leases	$ 17,446,421	$ 17,026,588	$ 16,623,401
Consumer Portfolio Segment [Member]
Segment Reporting Information [Line Items]
Loans and leases	$ 2,566,983	2,684,500	$ 2,707,343
Consumer Portfolio Segment [Member] | Home Equity Liquidating Portfolio [Member]
Segment Reporting Information [Line Items]
Loans and leases		$ 65,000

Commitments and Contingencies93

Commitments and Contingencies (Outstanding Financial Instruments Contract Amounts Represent Credit Risk) (Detail) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Loss Contingencies [Line Items]
Total credit-related financial instruments with off-balance sheet risk	$ 5,244,643	$ 5,399,762
Standby letter of credit [Member]
Loss Contingencies [Line Items]
Total credit-related financial instruments with off-balance sheet risk	159,485	128,985
Commercial letter of credit [Member]
Loss Contingencies [Line Items]
Total credit-related financial instruments with off-balance sheet risk	42,007	46,497
Commitments to extend credit [Member]
Loss Contingencies [Line Items]
Total credit-related financial instruments with off-balance sheet risk	$ 5,043,151	$ 5,224,280

(Reserve for Unfunded Commitmen

(Reserve for Unfunded Commitments) (Detail) - Allowance for Credit Loss [Member] - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Movement in Valuation Allowances and Reserves [Roll Forward]
Beginning balance	$ 2,544	$ 2,319	$ 2,287	$ 2,119
Provision charged to expense	0	172	257	372
Ending balance	$ 2,544	$ 2,491	$ 2,544	$ 2,491