Webster Financial (WBS) 10-Q 3 Aug 18 2018 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2018	Jul. 31, 2018
Document and Entity Information [Abstract]
Document Period End Date	Jun. 30, 2018
Document Type	10-Q
Amendment Flag	false
Entity Registrant Name	WEBSTER FINANCIAL CORPORATION
Entity Common Stock, Shares Outstanding		92,228,475
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	Q2
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	Jun. 30, 2018	Dec. 31, 2017
Assets:
Cash and due from banks	$ 228,628	$ 231,158
Interest-bearing deposits	70,654	25,628
Investment securities available-for-sale, at fair value	2,780,581	2,638,037
Investment securities held-to-maturity (fair value of $4,225,983 and $4,456,350)	4,356,219	4,487,392
Federal Home Loan Bank and Federal Reserve Bank stock	141,293	151,566
Loans held for sale, fair value option	18,645	20,888
Loans and leases	18,025,996	17,523,858
Allowance for loan and lease losses	(207,322)	(199,994)
Loans and leases, net	17,818,674	17,323,864
Deferred tax assets, net	106,910	92,630
Premises and equipment, net	127,973	130,001
Goodwill	538,373	538,373
Other intangible assets, net	27,688	29,611
Cash surrender value of life insurance policies	537,431	531,820
Accrued interest receivable and other assets	283,668	286,677
Total assets	27,036,737	26,487,645
Liabilities and shareholders' equity:
Noninterest-bearing Deposit Liabilities	4,151,259	4,191,496
Interest-bearing Deposit Liabilities	17,192,097	16,802,233
Total deposits	21,343,356	20,993,729
Securities sold under agreements to repurchase and other borrowings	862,568	643,269
Federal Home Loan Bank advances	1,576,956	1,677,105
Long-term debt	225,894	225,767
Accrued expenses and other liabilities	266,240	245,817
Total liabilities	24,275,014	23,785,687
Shareholders’ equity:
Common stock, $.01 par value: Authorized - 200,000,000 shares: Issued (93,651,601 shares)	937	937
Paid-in capital	1,115,414	1,122,164
Retained earnings	1,699,767	1,595,762
Treasury stock, at cost (1,645,784 and 1,658,526 shares)	(77,496)	(70,430)
Accumulated other comprehensive loss, net of tax	(121,936)	(91,531)
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	2,761,723	2,701,958
Total liabilities and shareholders' equity	27,036,737	26,487,645
Series F Preferred Stock [Member]
Shareholders’ equity:
Preferred stock, $.01 par value; Authorized - 3,000,000 shares: Series E issued and outstanding (5,060 shares)	$ 145,037	$ 145,056

Condensed Consolidated Balance3

Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Securities held-to-maturity ,fair value	$ 4,225,983	$ 4,456,350
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)	6,000	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)		93,680,291
Treasury stock ,shares (in shares)	1,645,784	1,658,526
Common Stock [Member]
Common stock, shares issued (in shares)	93,680,724

Condensed Consolidated Statemen

Condensed Consolidated Statements of Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Interest Income:
Interest and fees on loans and leases	$ 207,820	$ 174,456	$ 401,040	$ 342,264
Taxable interest and dividends on investments	47,427	46,408	94,715	92,348
Non-taxable interest on investment securities	5,096	5,722	10,367	11,338
Loans held for sale	148	203	290	519
Total interest income	260,491	226,789	506,412	446,469
Interest Expense:
Deposits	20,225	14,679	38,381	28,114
Securities sold under agreements to repurchase and other borrowings	3,998	3,583	7,638	7,123
Federal Home Loan Bank advances	8,471	8,156	15,752	15,649
Long-term debt	2,787	2,584	5,463	5,132
Total interest expense	35,481	29,002	67,234	56,018
Net interest income	225,010	197,787	439,178	390,451
Provision for loan and lease losses	10,500	7,250	21,500	17,750
Net interest income after provision for loan and lease losses	214,510	190,537	417,678	372,701
Non-interest Income:
Deposit service fees	40,859	38,192	81,310	75,198
Loan and lease related fees	6,333	6,344	13,329	13,552
Wealth and investment services	8,456	7,877	16,326	15,150
Mortgage banking activities	1,235	3,351	2,379	5,617
Increase in cash surrender value of life insurance policies	3,643	3,648	7,215	7,223
Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net	0	(126)	0	(126)
Other income	7,848	5,265	16,562	10,979
Total non-interest income	68,374	64,551	137,121	127,593
Non-interest Expense:
Compensation and benefits	93,052	86,394	187,817	173,893
Occupancy	15,842	16,034	30,987	32,213
Technology and equipment	24,604	22,458	48,466	44,066
Intangible assets amortization	962	1,028	1,924	2,083
Marketing	4,889	4,615	8,441	10,056
Professional and outside services	4,381	3,507	9,169	7,783
Deposit insurance	13,687	6,625	20,404	13,357
Other expense	23,042	23,758	44,866	44,752
Total non-interest expense	180,459	164,419	352,074	328,203
Income (loss) before income tax expense	102,425	90,669	202,725	172,091
Income tax expense	20,743	29,090	40,818	51,041
Net income	81,682	61,579	161,907	121,050
Preferred stock dividends and other	(2,193)	(2,094)	(4,334)	(4,224)
Earnings applicable to common shareholders	$ 79,489	$ 59,485	$ 157,573	$ 116,826
Earnings per common share:
Basic (in dollars per share)	$ 0.87	$ 0.65	$ 1.71	$ 1.27
Diluted (in dollars per share)	$ 0.86	$ 0.64	$ 1.71	$ 1.26

Condensed Consolidated Stateme5

Condensed Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Statement of Comprehensive Income [Abstract]
Net income	$ 81,682	$ 61,579	$ 161,907	$ 121,050
Other comprehensive (loss) income (OCL) OCI, net of tax:
Total securities available-for-sale	(9,246)	3,200	(36,670)	975
Total derivative instruments	1,680	651	4,202	1,810
Total defined benefit pension and other postretirement benefit plans	1,109	1,094	2,063	2,126
Other comprehensive (loss) income, net of tax	(6,457)	4,945	(30,405)	4,911
Comprehensive income	$ 75,225	$ 66,524	$ 131,502	$ 125,961

Condensed Consolidated Stateme6

Condensed Consolidated Statements of Shareholders' Equity (Unaudited) - USD ($) $ in Thousands	Total	Series E Preferred Stock [Member]	Series F Preferred Stock [Member]	Preferred Stock [Member]	Preferred Stock [Member]Series F Preferred Stock [Member]	Common Stock [Member]	Paid-In Capital [Member]	Retained Earnings [Member]	Retained Earnings [Member]Series E Preferred Stock [Member]	Retained Earnings [Member]Series F Preferred Stock [Member]	Treasury Stock, at cost [Member]	AOCI Attributable to Parent [Member]
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	121,050							121,050
Other comprehensive loss, net of tax	4,911											4,911
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	(47,058)						82	(47,140)
Dividends on Series E preferred stock $400.00 per share for the 3 months ended March 31, 2017 and 2016		$ 4,048							$ 4,048
Stock-based compensation	7,951						0	1,118			6,833
Exercise of stock options	4,591						(1,358)				5,949
Common shares acquired related to stock compensation plan activity	(9,283)										(9,283)
Ending Balance at Jun. 30, 2017	2,605,126			122,710		937	1,124,661	1,496,300			(67,400)	(72,082)
Beginning Balance at Mar. 31, 2017												(77,027)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	61,579
Other comprehensive loss, net of tax	4,945											4,945
Ending Balance at Jun. 30, 2017	2,605,126			122,710		937	1,124,661	1,496,300			(67,400)	(72,082)
Beginning Balance at Dec. 31, 2017	2,701,958			145,056		937	1,122,164	1,595,762			(70,430)	(91,531)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	161,907							161,907
Other comprehensive loss, net of tax	(30,405)											(30,405)
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	(54,179)						99	(54,278)
Dividends on Series E preferred stock $400.00 per share for the 3 months ended March 31, 2017 and 2016		$ (22)	$ 3,938						$ (22)	$ 3,938
Stock-based compensation	5,879						(1,541)	1,654			5,766
Exercise of stock options	2,110						(5,308)				7,418
Common shares acquired related to stock compensation plan activity	(8,092)										(8,092)
Common stock repurchase program	(12,158)										(12,158)
Ending Balance at Jun. 30, 2018	2,761,723			145,037		937	1,115,414	1,699,767			(77,496)	(121,936)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock Issued During Period, Value, Other			$ (19)		$ (19)
Beginning Balance at Mar. 31, 2018												(115,479)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	81,682
Other comprehensive loss, net of tax	(6,457)											(6,457)
Ending Balance at Jun. 30, 2018	2,761,723			$ 145,037		$ 937	$ 1,115,414	1,699,767			$ (77,496)	$ (121,936)
Cumulative Effect of New Accounting Principle in Period of Adoption	$ (1,362)							$ (1,362)

Condensed Consolidated Stateme7

Condensed Consolidated Statements of Shareholders' Equity (Unaudited) (Parenthetical) - $ / shares	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Dividends on common stock and dividend equivalents declared (in dollars per share)	$ 0.59	$ 0.51
Series E Preferred Stock [Member]
Dividends on preferred stock (in dollars per share)		$ 800
Series F Preferred Stock [Member]
Dividends on preferred stock (in dollars per share)	$ 667.1875

Condensed Consolidated Stateme8

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Operating Activities:
Net income	$ 161,907	$ 121,050
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for loan and lease losses	21,500	17,750
Deferred tax (benefit) expense	(4,247)	488
Depreciation and amortization	19,187	18,960
Amortization of earning assets and funding, premiums/discounts, net	26,625	23,287
Stock-based compensation	5,879	6,043
Gain on sale, net of write-down, on foreclosed and repossessed assets	(291)	(314)
Write-down, net on premises and equipment	253	559
Net increase in interest-bearing deposits	(45,026)	(4,201)
Impairment loss on investment securities recognized in earnings	0	126
Increase in cash surrender value of life insurance policies	(7,215)	(7,223)
Gain from life insurance policies	(825)	0
Mortgage banking activities	(2,379)	(5,617)
Proceeds from sale of loans held for sale	90,063	173,338
Origination of loans held for sale	(86,694)	(147,437)
Net decrease (increase) in derivative contract assets net of liabilities	65,421	(213)
Net increase in accrued interest receivable and other assets	(9,482)	(24,054)
Net (decrease) increase in accrued expenses and other liabilities	(23,176)	5,261
Net cash provided by operating activities	256,526	182,004
Investing Activities:
Purchases of available for sale investment securities	(455,042)	(106,476)
Proceeds from maturities and principal payments of available for sale investment securities	256,179	314,038
Purchases of held-to-maturity investment securities	(157,061)	(429,711)
Proceeds from maturities and principal payments of held-to-maturity investment securities	271,195	357,283
Net proceeds of Federal Home Loan Bank stock	10,273	39,141
Alternative investments (capital call) return of capital, net	(246)	296
Net increase in loans	(523,631)	(263,241)
Proceeds from loans not originated for sale	34	7,445
Proceeds from life insurance policies	2,429	484
Proceeds from the sale of foreclosed and repossessed assets	3,801	3,371
Proceeds from the sale of premises and equipment	0	507
Additions to premises and equipment	(16,063)	(13,392)
Proceeds from redemption of other assets	0	7,581
Net cash used for investing activities	(653,158)	(86,875)
Financing Activities:
Net increase in deposits	351,004	1,153,597
Proceeds from Federal Home Loan Bank advances	4,000,000	7,300,000
Repayments of Federal Home Loan Bank advances	(4,100,149)	(8,375,145)
Net decrease in securities sold under agreements to repurchase and other borrowings	219,299	(76,834)
Dividends paid to common shareholders	(53,974)	(46,862)
Dividends paid to preferred shareholders	(3,938)	(4,048)
Exercise of stock options	2,110	4,591
Common stock repurchase program	(12,158)	0
Common shares purchased related to stock compensation plan activity	(8,092)	(9,283)
Net cash (used for) provided by financing activities	394,102	(53,984)
Net decrease in cash and due from banks	(2,530)	41,145
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents Beginning of Period	231,158	190,663
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents End of Period	228,628	231,808
Supplemental disclosure of cash flow information:
Interest paid	64,009	53,354
Income taxes paid	47,781	53,334
Noncash investing and financing activities:
Real Estate Owned, Transfer to Real Estate Owned	3,406	3,167
Transfer of loans from portfolio to loans-held-for-sale	$ 35	$ 0

Summary of Significant Accounti

Summary of Significant Accounting Policies	6 Months Ended
	Jun. 30, 2018
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 June 30, 2018 , Webster Financial Corporation's principal asset is all of the outstanding capital stock of Webster Bank, National Association (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 U.S. Generally Accepted Accounting Principles (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, 2017 , included in the Company's Annual Report on Form 10-K filed with the U.S. Securities and Exchange Commission (SEC) on March 1, 2018. Use of Estimates The preparation of financial statements in accordance with GAAP requires management to make estimates and assumptions that affect the amounts of assets and liabilities as of the date of the financial statements as well as income and expense during the period. Actual results could differ from those estimates. 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. Federal Deposit Insurance Corporation (FDIC) Assessment. The Company recorded a $7.2 million charge to establish an accrual for additional FDIC premiums for prior periods. The accrual is management's estimate of the aggregate amount of premiums due for the period from March 31, 2015 through December 31, 2017 and is the result of a reclassification of loans under existing and modified FDIC loan category classifications. Any additional expense that may result upon final resolution of this matter is expected to be immaterial to the Company's financial statements. The matter is expected to be resolved prior to December 31, 2018. Accounting Standards Adopted During 2018 Effective January 1, 2018 , the following new Accounting Standards Updates (ASUs) were adopted by the Company: ASU No. 2017-08, Receivables - Nonrefundable Fees and Other Costs (Subtopic 310-20) - Premium Amortization on Purchased Callable Debt Securities. The Update shortens the amortization period for certain investments in callable debt securities purchased at a premium by requiring that the premium be amortized to the earliest call date. Prior to adoption, the Company amortized the premium as a yield adjustment over the contractual life of such debt securities. The Update accelerates the Company's recognition of premium amortization on certain debt securities held within the portfolio. The Company adopted the Update during the first quarter of 2018 on a modified retrospective basis. As a result, the Company recorded a $2.8 million cumulative-effect adjustment directly to retained earnings as of January 1, 2018. ASU No. 2017-07, Compensation - Retirement Benefits (Topic 715) - Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost. The Update requires the Company to retrospectively report service cost as a part of compensation expense and the other components of net periodic benefit cost separately from service cost in the Company's consolidated financial statements. The Company previously included all components of net periodic benefit cost as a component of compensation and benefits expense. Upon adoption, only service cost remains in compensation and benefits expense, while the interest cost on benefit obligations, expected return on plan assets, amortization of prior service cost, and recognized net loss components of the net periodic benefit cost are included in other expense, in the accompanying Condensed Consolidated Statements of Income. The Company adopted the Update during the first quarter of 2018 on a retrospective basis. As a result, the Company reclassified, for prior periods, the components of it's net periodic benefit costs other than the service cost component from compensation and benefits to other expense in the accompanying Condensed Consolidated Statements of Income. The adoption of this guidance did not have a material impact on the Company's consolidated financial statements. ASU No. 2016-15, Statement of Cash Flows (Topic 230) - Classification of Certain Cash Receipts and Cash Payments. The Update addresses the following eight specific cash flow issues, with the objective of reducing the existing diversity in practice: debt prepayment or debt extinguishment costs; settlement of zero-coupon debt instruments or other debt instruments with coupon interest rates that are insignificant in relation to the effective interest rate of the borrowing; contingent consideration payments made after a business combination; proceeds from the settlement of insurance claims; proceeds from the settlement of corporate-owned life insurance policies, including bank-owned life insurance policies; distributions received from equity method investees; beneficial interests in securitization transactions; and separately identifiable cash flows and application of the predominance principle. The Company adopted the Update during the first quarter of 2018 on a retrospective basis. The adoption of this guidance did not have a material impact on the Company's consolidated financial statements. ASU No. 2016-01, Financial Instruments - Overall (Subtopic 825-10) - Recognition and Measurement of Financial Assets and Financial Liabilities, and ASU No. 2018-03, Technical Corrections and Improvements to Financial Instruments - Overall (Subtopic 825-10) The Updates included targeted amendments in connection with the recognition, measurement, presentation, and disclosure of financial instruments. The main provisions require investments in equity securities to be measured at fair value through net income, unless they qualify for a practical expedient, and require fair value changes arising from changes in instrument-specific credit risk for financial liabilities that are measured under the fair value option to be recognized in other comprehensive income. The provisions also emphasized the existing requirement to use exit prices to measure fair value for disclosure purposes. The Company adopted the Updates during the first quarter of 2018 primarily on a modified retrospective basis. As a result, the Company recorded a benefit of $1.4 million for a cumulative-effect adjustment directly to retained earnings, as of January 1, 2018, due to a change in valuation method, from cost less impairment, to net asset value using the practical expedient. Also, the measurement alternative has been elected for equity securities, existing as of January 1, 2018, without readily determinable fair values on a prospective basis. ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606) and subsequent ASUs issued to clarify this Topic. The Update, and subsequent related updates, establish a single comprehensive model for entities to use in accounting for revenue arising from contracts with customers and supersedes most previous revenue recognition guidance, including industry-specific guidance. The Updates are intended to increase comparability across industries. The core principle of the revenue model is that a company will recognize revenue when it transfers control of goods or services to customers, at an amount that reflects the consideration to which it expects to be entitled in exchange for those goods or services. The Company adopted the Updates during the first quarter of 2018 on a modified retrospective transition approach. The Company did not identify any material changes to the timing of revenue recognition. The Company is changing how it presents certain recurring revenue streams associated with wealth and investment services as other income, versus a contra expense; however, these changes did not have a significant impact on the Company's consolidated financial statements. The adoption of this guidance did not have a material impact on the Company's financial condition or results of operations, and there was no cumulative effect adjustment to opening retained earnings as no material changes were identified in the timing of revenue recognition, however, additional disclosure has been incorporated in Note 17: Revenue from Contracts with Customers . Accounting Standards Issued But Not Yet Adopted The following list identifies ASUs applicable to the Company that have been issued by the FASB but are not yet effective: ASU No. 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 a Company will recognize a cumulative effect of the change on the opening balance for each affected component of equity in the financial statements as of the date of adoption. The Update is effective for the Company on January 1, 2019. The Company does not expect the new guidance to have a material impact on its financial statements. ASU No. 2017-04, Intangibles - Goodwill and Other (Topic 350) - Simplifying the Test for Goodwill Impairment. The Update simplifies quantitative goodwill impairment testing by requiring entities to compare the fair value of a reporting unit with its carrying amount and recognize an impairment charge for any amount by which the carrying amount exceeds the reporting unit's fair value, to the extent that the loss recognized does not exceed the amount of goodwill allocated to that reporting unit. This changes current guidance by eliminating the second step of the goodwill impairment analysis which involves calculating the implied fair value of goodwill determined in the same manner as the amount of goodwill recognized in a business combination upon acquisition. Entities will still have the option to perform the qualitative assessment for a reporting unit to determine if the quantitative impairment test is necessary. The Update is effective for the Company on January 1, 2020 and early adoption is permitted. The Update must be applied prospectively. The Company does not expect the new guidance to have a material impact on its 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. This approach 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 may result in a material increase to the Company's accounting for credit losses on financial instruments. To prepare for implementation of the new standard the Company has established a project lead and has empowered a cross functional steering committee comprised of members from different disciplines including Credit, Finance and Treasury as well as specific working groups to focus on key components of the development process. Through these working groups, the Company has begun to evaluate the effect that this Update will have on its financial statements and related disclosures. An implementation project plan has been created and is made up of targeted work streams focused on credit models, data management, treasury, and accounting. These work streams are collectively assessing resources that may be required, use of existing and new models, and data availability. The Company recently contracted with a system solution provider and is preparing to commence its implementation. The Update is effective for the Company on January 1, 2020. The impact of adopting the Update is expected to be influenced by assessment of the composition, characteristics, and credit quality of our loan and securities portfolios as well as the economic conditions in effect at the adoption date. Therefore, we are currently unable to reasonably estimate the impact of adopting the Update at this time. ASU No. 2016-02, Leases (Topic 842) and subsequent ASUs issued to amend this Topic. The Update introduces a lessee model that requires substantially all leases to be recorded as assets and liabilities on the balance sheet and will require both quantitative and qualitative disclosures regarding key information about leasing arrangements. In July 2018, the FASB issued a subsequent Update which, among other issues, incorporates a new transition method option that would allow the Company to use the effective date as the date of initial application on transition. The Company currently expects to elect this transition method. The Company is in the process of reviewing its existing leases, and certain service contracts for embedded leases, to evaluate the impact of these Updates on the consolidated financial statements, as well as the impact to regulatory reporting, such as capital and risk-weighted assets. The Company has engaged a third party consultant to assist with the implementation efforts and has selected a third party software solution to assist with the accounting under these Updates.

Variable Interest Entities

Variable Interest Entities	6 Months Ended
	Jun. 30, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Variable Interest Entities	Variable Interest Entities The Company has an investment interest in the following entities that meet the definition of a variable interest entity (VIE). Consolidated Rabbi Trust. The Company established a Rabbi Trust to meet the obligations due under its Deferred Compensation Plan for Directors and Officers and to mitigate the expense volatility of the aforementioned plan. The funding of the Rabbi Trust and the discontinuation of the Deferred Compensation Plan for Directors and Officers occurred during 2012. Investments held in the Rabbi Trust primarily consist of mutual funds that invest in equity and fixed income securities. The Company is considered the primary beneficiary of the Rabbi Trust as it has the power to direct the activities of the Rabbi Trust that significantly affect the VIE's economic performance and it has the obligation to absorb losses of the VIE that could potentially be significant to the VIE. The Company consolidates the invested assets of the trust along with the total deferred compensation obligations and includes them in accrued interest receivable and other assets and accrued expenses and other liabilities, respectively, in the accompanying 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. See Note 13: Fair Value Measurements for additional information. Non-Consolidated Securitized Investments. The Company, through normal investment activities, makes passive investments in securities issued by VIEs for which Webster is not the manager. The investment securities consist of Agency CMO, Agency MBS, Agency CMBS, and CLO. The Company has not provided financial or other support with respect to these investment securities other than its original investment. For these investment securities, the Company determined it is not the primary beneficiary due to the relative size of its investment in comparison to the principal amount of the structured securities issued by the VIEs, the level of credit subordination which reduces the Company’s obligation to absorb losses or right to receive benefits and its inability to direct the activities that most significantly impact the economic performance of the VIEs. The Company’s maximum exposure to loss is limited to the amount of its investment in the VIEs. See Note 3: Investment Securities for additional information. Tax Credit - Finance Investments. The Company makes equity investments in entities that finance affordable housing and other community development projects and provide a return primarily through the realization of tax benefits. In most instances the investments require the funding of capital commitments in the future. While the Company's investment in an entity may exceed 50% of its outstanding equity interests, the entity is not consolidated as Webster is not involved in its management. For these investments, the Company determined it is not the primary beneficiary due to its inability to direct the activities that most significantly impact the economic performance of the VIEs. The Company applies the proportional amortization method to account for its investments in qualified affordable housing projects. At June 30, 2018 and December 31, 2017 , the aggregate carrying value of the Company's tax credit-finance investments were $31.0 million and $33.5 million , respectively. At June 30, 2018 and December 31, 2017 , unfunded commitments have been recognized, totaling $11.1 million and $17.3 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 the outstanding common stock of Webster Statutory Trust, a financial vehicle that has issued, and in the future may issue, trust preferred securities. The trust is a VIE in which the Company is not the primary beneficiary. The trust's only assets are junior subordinated debentures issued by the Company, which were acquired by the trust using the proceeds from the issuance of the trust preferred securities and common stock. The junior subordinated debentures are included in long-term debt in the accompanying 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. These investments are non-public entities which cannot be redeemed since the Company’s investment is distributed as the underlying equity is liquidated. For these investments, the Company has determined it is not the primary beneficiary due to its inability to direct the activities that most significantly impact the economic performance of the VIEs. At June 30, 2018 and December 31, 2017 , the aggregate carrying value of the Company's other investments in VIEs were $14.6 million and $13.8 million , respectively, and the total exposure of the Company's other investments in VIEs, including unfunded commitments, were $27.5 million and $22.9 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 description of the Company's accounting policy regarding the consolidation of VIEs, refer to Note 1 to the Consolidated Financial Statements included in its Form 10-K, for the year ended December 31, 2017

Investment Securities

Investment Securities	6 Months Ended
	Jun. 30, 2018
Investments, Debt and Equity Securities [Abstract]
Investment Securities	Investment Securities A summary of the amortized cost and fair value of investment securities is presented below: At June 30, 2018 At December 31, 2017 (In thousands) Amortized Cost Unrealized Gains Unrealized Losses Fair Value Amortized Cost Unrealized Gains Unrealized Losses Fair Value Available-for-sale: U.S. Treasury Bills $ 2,491 $ — $ — $ 2,491 $ 1,247 $ — $ — $ 1,247 Agency CMO 271,712 268 (6,727 ) 265,253 308,989 1,158 (3,814 ) 306,333 Agency MBS 1,356,988 1,053 (46,200 ) 1,311,841 1,124,960 2,151 (19,270 ) 1,107,841 Agency CMBS 618,054 — (35,378 ) 582,676 608,276 — (20,250 ) 588,026 CMBS 373,916 958 (318 ) 374,556 358,984 2,157 (74 ) 361,067 CLO 187,697 538 (169 ) 188,066 209,075 910 (134 ) 209,851 Single issuer-trust preferred — — — — 7,096 — (46 ) 7,050 Corporate debt 56,197 404 (903 ) 55,698 56,504 797 (679 ) 56,622 Available-for-sale $ 2,867,055 $ 3,221 $ (89,695 ) $ 2,780,581 $ 2,675,131 $ 7,173 $ (44,267 ) $ 2,638,037 Held-to-maturity: Agency CMO $ 231,943 $ 296 $ (7,891 ) $ 224,348 $ 260,114 $ 664 $ (4,824 ) $ 255,954 Agency MBS 2,520,455 10,139 (90,415 ) 2,440,179 2,569,735 16,989 (37,442 ) 2,549,282 Agency CMBS 677,397 — (24,594 ) 652,803 696,566 — (10,011 ) 686,555 Municipal bonds and notes 697,066 1,948 (16,851 ) 682,163 711,381 8,584 (6,558 ) 713,407 CMBS 229,265 551 (3,419 ) 226,397 249,273 2,175 (620 ) 250,828 Private Label MBS 93 — — 93 323 1 — 324 Held-to-maturity $ 4,356,219 $ 12,934 $ (143,170 ) $ 4,225,983 $ 4,487,392 $ 28,413 $ (59,455 ) $ 4,456,350 Other-Than-Temporary Impairment The amount in the amortized cost columns in the table above includes other-than-temporary impairment (OTTI) related to certain CLO positions that were previously considered Covered Funds as defined by Section 619 of the Dodd-Frank Wall Street Reform and Consumer Protection Act of 2010 (Dodd-Frank Act), commonly known as the Volcker Rule. The Company has taken measures to bring its CLO positions into conformance with the Volcker Rule. The following table presents activity for OTTI: Three months ended June 30, Six months ended June 30, (In thousands) 2018 2017 2018 2017 Beginning balance $ 1,364 $ 3,231 $ 1,364 $ 3,243 Reduction for investment securities sold or called (261 ) (126 ) (261 ) (138 ) Additions for OTTI not previously recognized in earnings — 126 — 126 Ending balance $ 1,103 $ 3,231 $ 1,103 $ 3,231 To the extent that changes occur in interest rates, credit movements, or other factors that impact fair value and expected recovery of amortized cost of its investment securities, the Company may, in future periods, be required to recognize OTTI in earnings. Fair Value and Unrealized Losses The following tables provide information on fair value and unrealized losses for the individual investment securities with an unrealized loss, aggregated by classification and length of time that the individual investment securities have been in a continuous unrealized loss position: At June 30, 2018 Less Than Twelve Months Twelve Months or Longer Total (Dollars in thousands) Fair Value Unrealized Losses Fair Value Unrealized Losses # of Holdings Fair Value Unrealized Losses Available-for-sale: Agency CMO $ 110,795 $ (1,853 ) $ 112,410 $ (4,874 ) 36 $ 223,205 $ (6,727 ) Agency MBS 645,678 (16,586 ) 552,321 (29,614 ) 165 1,197,999 (46,200 ) Agency CMBS 71,430 (2,761 ) 511,246 (32,617 ) 37 582,676 (35,378 ) CMBS 145,960 (318 ) — — 22 145,960 (318 ) CLO 41,259 (41 ) 15,029 (128 ) 3 56,288 (169 ) Single issuer-trust preferred — — — — — — — Corporate debt 36,073 (278 ) 1,770 (625 ) 5 37,843 (903 ) Available-for-sale in an unrealized loss position $ 1,051,195 $ (21,837 ) $ 1,192,776 $ (67,858 ) 268 $ 2,243,971 $ (89,695 ) Held-to-maturity: Agency CMO $ 100,551 $ (2,735 ) $ 96,424 $ (5,156 ) 24 $ 196,975 $ (7,891 ) Agency MBS 1,085,492 (29,208 ) 1,111,469 (61,207 ) 262 2,196,961 (90,415 ) Agency CMBS 518,344 (18,421 ) 134,459 (6,173 ) 56 652,803 (24,594 ) Municipal bonds and notes 250,878 (5,417 ) 218,705 (11,434 ) 212 469,583 (16,851 ) CMBS 147,266 (3,149 ) 12,758 (270 ) 20 160,024 (3,419 ) Held-to-maturity in an unrealized loss position $ 2,102,531 $ (58,930 ) $ 1,573,815 $ (84,240 ) 574 $ 3,676,346 $ (143,170 ) At December 31, 2017 Less Than Twelve Months Twelve Months or Longer Total (Dollars in thousands) Fair Value Unrealized Losses Fair Value Unrealized Losses # of Holdings Fair Value Unrealized Losses Available-for-sale: Agency CMO $ 81,001 $ (449 ) $ 119,104 $ (3,365 ) 27 $ 200,105 $ (3,814 ) Agency MBS 416,995 (2,920 ) 606,021 (16,350 ) 135 1,023,016 (19,270 ) Agency CMBS 54,182 (851 ) 533,844 (19,399 ) 36 588,026 (20,250 ) CMBS 23,869 (74 ) — — 6 23,869 (74 ) CLO 56,335 (134 ) — — 3 56,335 (134 ) Single issuer-trust preferred 7,050 (46 ) — — 1 7,050 (46 ) Corporate debt 11,082 (395 ) 6,265 (284 ) 4 17,347 (679 ) Available-for-sale in an unrealized loss position $ 650,514 $ (4,869 ) $ 1,265,234 $ (39,398 ) 212 $ 1,915,748 $ (44,267 ) Held-to-maturity: Agency CMO $ 98,090 $ (1,082 ) $ 106,775 $ (3,742 ) 22 $ 204,865 $ (4,824 ) Agency MBS 762,107 (4,555 ) 1,197,839 (32,887 ) 205 1,959,946 (37,442 ) Agency CMBS 576,770 (7,599 ) 109,785 (2,412 ) 56 686,555 (10,011 ) Municipal bonds and notes 6,432 (38 ) 226,861 (6,520 ) 92 233,293 (6,558 ) CMBS 92,670 (413 ) 14,115 (207 ) 13 106,785 (620 ) Held-to-maturity in an unrealized loss position $ 1,536,069 $ (13,687 ) $ 1,655,375 $ (45,768 ) 388 $ 3,191,444 $ (59,455 ) Impairment Analysis The following impairment analysis summarizes the basis for evaluating if investment securities within the Company’s available-for-sale and held-to-maturity portfolios have been impacted by OTTI since December 31, 2017 . Unless otherwise noted for an investment security type, management does not intend to sell these investment securities and has determined, based upon available evidence, that it is more likely than not that the Company will not be required to sell these investment securities before the recovery of their amortized cost. As such, based on the following impairment analysis, the Company does not consider any of these investment securities, in unrealized loss positions, to be other-than-temporarily impaired at June 30, 2018 . Available-for-Sale Securities Agency CMO. There were unrealized losses of $6.7 million on the Company’s investment in Agency CMO at June 30, 2018 , compared to $3.8 million at December 31, 2017 . Unrealized losses increased due to higher market rates while principal balances decreased for this asset class since December 31, 2017 . These investments are issued by a government or government sponsored agency and therefore, are backed by certain government guarantees, either direct or implicit. There has been no change in the credit quality, and the contractual cash flows are performing as expected. Agency MBS. There were unrealized losses of $46.2 million on the Company’s investment in residential mortgage-backed securities issued by government agencies at June 30, 2018 , compared to $19.3 million at December 31, 2017 . Unrealized losses increased due to higher market rates while principal balances increased for this asset class since December 31, 2017 . These investments are issued by a government or government sponsored agency and therefore, are backed by certain government guarantees, either direct or implicit. There has been no change in the credit quality, and the contractual cash flows are performing as expected. Agency CMBS. There were unrealized losses of $35.4 million on the Company's investment in commercial mortgage-backed securities issued by government agencies at June 30, 2018 , compared to $20.3 million at December 31, 2017 . Unrealized losses increased due to higher market rates while principal balances increased for this asset class since December 31, 2017 . These investments are issued by a government or government sponsored agency and therefore, are backed by certain government guarantees, either direct or implicit. There has been no change in the credit quality, and the contractual cash flows are performing as expected. CMBS. There were unrealized losses of $318 thousand on the Company’s investment in CMBS at June 30, 2018 , compared to $74 thousand at December 31, 2017 . Unrealized losses and balances were essentially unchanged for the portfolio of mainly floating rate CMBS at June 30, 2018 compared to December 31, 2017 . Internal stress tests are performed on individual bonds to monitor potential losses under stress scenarios. Contractual cash flows for the bonds continue to perform as expected. CLO. There were unrealized losses of $169 thousand on the Company’s investments in CLO at June 30, 2018 compared to $134 thousand unrealized losses at December 31, 2017 . Unrealized losses were essentially unchanged while principal balances decreased from December 31, 2017 . Internal stress tests are performed on individual bonds to monitor potential losses under stress scenarios. Contractual cash flows for the bonds continue to perform as expected. Corporate debt. There were unrealized losses of $903 thousand on the Company's corporate debt portfolio at June 30, 2018 , compared to $679 thousand at December 31, 2017 . Unrealized losses and balances were essentially unchanged since December 31, 2017 . The Company performs periodic credit reviews of the issuer to assess the likelihood for ultimate recovery of amortized cost. Held-to-Maturity Securities Agency CMO. There were unrealized losses of $7.9 million on the Company’s investment in Agency CMO at June 30, 2018 , compared to $4.8 million at December 31, 2017 . Unrealized losses increased due to higher market rates while principal balances decreased since December 31, 2017 . These investments are issued by a government or government sponsored agency and therefore, are backed by certain government guarantees, either direct or implicit. There has been no change in the credit quality, and the contractual cash flows are performing as expected. Agency MBS. There were unrealized losses of $90.4 million on the Company’s investment in residential mortgage-backed securities issued by government agencies at June 30, 2018 , compared to $37.4 million at December 31, 2017 . Unrealized losses increased due to higher market rates while principal balances were essentially unchanged for this asset class since December 31, 2017 . These investments are issued by a government or government sponsored agency and therefore, are backed by certain government guarantees, either direct or implicit. There has been no change in the credit quality, and the contractual cash flows are performing as expected. Agency CMBS. There were unrealized losses of $24.6 million on the Company’s investment in commercial mortgage-backed securities issued by government agencies at June 30, 2018 , compared to $10.0 million at December 31, 2017 . Unrealized losses increased due to higher market rates while principal balances decreased since December 31, 2017 . These investments are issued by a government or government sponsored agency and therefore, are backed by certain government guarantees, either direct or implicit. There has been no change in the credit quality, and the contractual cash flows are performing as expected. Municipal bonds and notes. There were unrealized losses of $16.9 million on the Company’s investment in municipal bonds and notes at June 30, 2018 , compared to $6.6 million at December 31, 2017 . Unrealized losses increased due to higher market rates while principal balances decreased since December 31, 2017 . The Company performs periodic credit reviews of the issuers and the securities are currently performing as expected. CMBS. There were unrealized losses of $3.4 million on the Company’s investment in CMBS at June 30, 2018 , compared to $0.6 million unrealized losses at December 31, 2017 . Unrealized losses increased due to higher market rates on mainly seasoned fixed rate conduit transactions while principal balances decreased since December 31, 2017 . Internal stress tests are performed on individual bonds to monitor potential losses under stress scenarios. There has been no change in the credit quality, and the contractual cash flows are performing as expected. Sales of Available-for Sale Investment Securities There were no sales during the three and six months ended June 30, 2018 and 2017 . Contractual Maturities The amortized cost and fair value of debt securities by contractual maturity are set forth below: At June 30, 2018 Available-for-Sale Held-to-Maturity (In thousands) Amortized Cost Fair Value Amortized Cost Fair Value Due in one year or less $ 23,192 $ 23,191 $ 17,891 $ 18,013 Due after one year through five years 34,000 34,083 3,628 3,656 Due after five through ten years 314,281 313,644 40,865 40,977 Due after ten years 2,495,582 2,409,663 4,293,835 4,163,337 Total debt securities $ 2,867,055 $ 2,780,581 $ 4,356,219 $ 4,225,983 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 June 30, 2018 , the Company had a carrying value of $1.3 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 $2.4 billion at both June 30, 2018 and December 31, 2017

Loans and Leases

Loans and Leases	6 Months Ended
	Jun. 30, 2018
Loans and Leases Receivable Disclosure [Abstract]
Loans and Leases	Loans and Leases The following table summarizes loans and leases: (In thousands) At June 30, At December 31, 2017 Residential $ 4,455,580 $ 4,490,878 Consumer 2,485,695 2,590,225 Commercial 5,981,556 5,368,694 Commercial Real Estate 4,580,200 4,523,828 Equipment Financing 522,965 550,233 Loans and leases (1) (2) $ 18,025,996 $ 17,523,858 (1) Loans and leases include net deferred fees and net premiums/discounts of $16.4 million and $20.6 million at June 30, 2018 and December 31, 2017 , respectively. (2) At June 30, 2018 the Company had pledged $6.5 billion of eligible residential, consumer, and commercial loans as collateral to support borrowing capacity at the Federal Home Loan Bank (FHLB) Boston and the Federal Reserve Bank (FRB) of Boston. Loans and Leases Aging The following tables summarize the aging of loans and leases: At June 30, 2018 (In thousands) 30-59 Days Past Due and Accruing 60-89 Days 90 or More Days Past Due and Accruing Non-accrual Total Past Due and Non-accrual Current Total Loans Residential $ 6,449 $ 4,449 $ — $ 50,780 $ 61,678 $ 4,393,902 $ 4,455,580 Consumer: Home equity 8,286 3,022 — 36,849 48,157 2,208,522 2,256,679 Other consumer 1,860 1,215 — 1,583 4,658 224,358 229,016 Commercial: Commercial non-mortgage 3,410 1,790 62 36,687 41,949 4,979,771 5,021,720 Asset-based — — — 1,160 1,160 958,676 959,836 Commercial real estate: Commercial real estate 720 — — 9,609 10,329 4,411,603 4,421,932 Commercial construction — — — — — 158,268 158,268 Equipment financing 1,991 331 — 3,510 5,832 517,133 522,965 Total $ 22,716 $ 10,807 $ 62 $ 140,178 $ 173,763 $ 17,852,233 $ 18,025,996 At December 31, 2017 (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 $ 8,643 $ 5,146 $ — $ 44,481 $ 58,270 $ 4,432,608 $ 4,490,878 Consumer: Home equity 12,668 5,770 — 35,645 54,083 2,298,185 2,352,268 Other consumer 2,556 1,444 — 1,707 5,707 232,250 237,957 Commercial: Commercial non-mortgage 5,212 603 644 39,214 45,673 4,488,242 4,533,915 Asset-based — — — 589 589 834,190 834,779 Commercial real estate: Commercial real estate 478 77 248 4,484 5,287 4,238,987 4,244,274 Commercial construction — — — — — 279,554 279,554 Equipment financing 1,732 626 — 393 2,751 547,482 550,233 Total $ 31,289 $ 13,666 $ 892 $ 126,513 $ 172,360 $ 17,351,498 $ 17,523,858 Interest on non-accrual loans and leases that would have been recorded as additional interest income had the loans and leases been current in accordance with the original terms totaled $2.4 million and $2.6 million for the three months ended June 30, 2018 and 2017 , respectively, and $4.3 million and $4.5 million for the six months ended June 30, 2018 and 2017 , 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 allowance for loan and lease losses (ALLL): At or for the three months ended June 30, 2018 Residential Consumer Commercial Commercial Real Estate Equipment Financing Total ALLL: Balance, beginning of period $ 18,777 $ 34,239 $ 95,573 $ 51,436 $ 5,324 $ 205,349 Provision charged to expense 659 813 4,490 4,428 110 10,500 Charge-offs (754 ) (4,907 ) (5,632 ) (40 ) (65 ) (11,398 ) Recoveries 325 1,614 909 9 14 2,871 Balance, end of period $ 19,007 $ 31,759 $ 95,340 $ 55,833 $ 5,383 $ 207,322 At or for the three months ended June 30, 2017 (In thousands) Residential Consumer Commercial Commercial Real Estate Equipment Financing Total ALLL: Balance, beginning of period $ 20,264 $ 45,408 $ 76,354 $ 50,727 $ 6,354 $ 199,107 (Benefit) provision charged to expense (1,621 ) 1,562 5,489 1,771 49 7,250 Charge-offs (623 ) (5,602 ) (2,196 ) (100 ) (119 ) (8,640 ) Recoveries 407 1,120 317 4 13 1,861 Balance, end of period $ 18,427 $ 42,488 $ 79,964 $ 52,402 $ 6,297 $ 199,578 At or for the six months ended June 30, 2018 (In thousands) Residential Consumer Commercial Commercial Real Estate Equipment Financing Total ALLL: Balance, beginning of period $ 19,058 $ 36,190 $ 89,533 $ 49,407 $ 5,806 $ 199,994 Provision (benefit) charged to expense 909 2,493 11,910 6,532 (344 ) 21,500 Charge-offs (1,671 ) (9,981 ) (7,129 ) (117 ) (110 ) (19,008 ) Recoveries 711 3,057 1,026 11 31 4,836 Balance, end of period $ 19,007 $ 31,759 $ 95,340 $ 55,833 $ 5,383 $ 207,322 Individually evaluated for impairment $ 4,330 $ 1,498 $ 6,007 $ 2,061 $ 18 $ 13,914 Collectively evaluated for impairment $ 14,677 $ 30,261 $ 89,333 $ 53,772 $ 5,365 $ 193,408 Loan and lease balances: Individually evaluated for impairment $ 109,636 $ 41,636 $ 87,071 $ 12,677 $ 6,185 $ 257,205 Collectively evaluated for impairment 4,345,944 2,444,059 5,894,485 4,567,523 516,780 17,768,791 Loans and leases $ 4,455,580 $ 2,485,695 $ 5,981,556 $ 4,580,200 $ 522,965 $ 18,025,996 At or for the six months ended June 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 (4,088 ) 6,888 9,739 5,116 95 17,750 Charge-offs (1,355 ) (12,076 ) (2,319 ) (202 ) (304 ) (16,256 ) Recoveries 644 2,443 639 11 27 3,764 Balance, end of period $ 18,427 $ 42,488 $ 79,964 $ 52,402 $ 6,297 $ 199,578 Individually evaluated for impairment $ 5,105 $ 1,829 $ 10,951 $ 324 $ 27 $ 18,236 Collectively evaluated for impairment $ 13,322 $ 40,659 $ 69,013 $ 52,078 $ 6,270 $ 181,342 Loan and lease balances: Individually evaluated for impairment $ 117,820 $ 47,310 $ 83,206 $ 18,677 $ 6,332 $ 273,345 Collectively evaluated for impairment 4,270,488 2,552,008 5,060,965 4,537,531 579,341 17,000,333 Loans and leases $ 4,388,308 $ 2,599,318 $ 5,144,171 $ 4,556,208 $ 585,673 $ 17,273,678 Impaired Loans and Leases The following tables summarize impaired loans and leases: At June 30, 2018 (In thousands) Unpaid Principal Balance Total Recorded Investment No Allowance Recorded Investment With Allowance Related Valuation Allowance Residential $ 120,019 $ 109,636 $ 68,854 $ 40,782 $ 4,330 Consumer - home equity 46,758 41,636 32,140 9,496 1,498 Commercial : Commercial non-mortgage 99,170 85,911 52,522 33,389 6,007 Asset-based 1,197 1,160 1,160 — — Commercial real estate: Commercial real estate 13,490 12,677 2,812 9,865 2,061 Commercial construction — — — — — Equipment financing 6,254 6,185 5,792 393 18 Total $ 286,888 $ 257,205 $ 163,280 $ 93,925 $ 13,914 At December 31, 2017 (In thousands) Unpaid Principal Balance Total Recorded Investment No Allowance Recorded Investment With Allowance Related Valuation Allowance Residential $ 125,352 $ 114,295 $ 69,759 $ 44,536 $ 4,805 Consumer - home equity 50,809 45,436 34,418 11,018 1,668 Commercial : Commercial non-mortgage 79,900 71,882 27,313 44,569 9,786 Asset-based 3,272 589 589 — — Commercial real estate: Commercial real estate 11,994 11,226 6,387 4,839 272 Commercial construction — — — — — Equipment financing 3,409 3,325 2,932 393 23 Total $ 274,736 $ 246,753 $ 141,398 $ 105,355 $ 16,554 The following table summarizes the average recorded investment and interest income recognized for impaired loans and leases: Three months ended June 30, Six months ended June 30, 2018 2017 2018 2017 (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 $ 110,787 $ 948 $ 265 $ 119,398 $ 1,036 $ 286 $ 111,965 $ 1,929 $ 518 $ 118,622 $ 2,106 $ 701 Consumer - home equity 42,112 290 250 47,296 335 249 43,536 584 500 46,514 657 562 Commercial: Commercial non-mortgage 80,475 871 — 85,006 233 — 78,896 1,410 — 68,122 455 — Asset based 1,347 — — — — — 875 — — — — — Commercial real estate: Commercial real estate 11,802 38 — 20,454 98 — 11,951 134 — 20,851 233 — Commercial construction — — — 862 — — — — — 865 12 — Equipment financing 6,320 35 — 6,240 67 — 4,755 71 — 6,376 138 — Total $ 252,843 $ 2,182 $ 515 $ 279,256 $ 1,769 $ 535 $ 251,978 $ 4,128 $ 1,018 $ 261,350 $ 3,601 $ 1,263 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 default (PD) and the loss given default (LGD). The credit risk grade system assigns a rating to each borrower and to the facility, which together form a Composite Credit Risk Profile. The credit risk grade system categorizes borrowers by common financial characteristics that measure the credit strength of borrowers and facilities by common structural characteristics. The Composite Credit Risk Profile has ten grades, with each grade corresponding to a progressively greater risk of 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 June 30, At December 31, At June 30, At December 31, At June 30, At December 31, (1) - (6) Pass $ 5,574,419 $ 5,048,162 $ 4,422,144 $ 4,355,916 $ 497,193 $ 525,105 (7) Special Mention 172,017 104,594 48,683 62,065 6,490 8,022 (8) Substandard 226,275 206,883 109,373 105,847 19,282 17,106 (9) Doubtful 8,845 9,055 — — — — Total $ 5,981,556 $ 5,368,694 $ 4,580,200 $ 4,523,828 $ 522,965 $ 550,233 For residential and consumer loans, the primary credit quality indicator that the Company considers is past due status. Other factors, such as, updated Fair Isaac Corporation (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 may also be evaluated. On an ongoing basis for portfolio monitoring purposes, the Company estimates the current value of property secured as collateral for home equity and residential first mortgage lending products. The estimate is based on home price indices compiled by the S&P/Case-Shiller Home Price Indices. The real estate price data is applied to the loan portfolios taking into account the age of the most recent valuation and geographic area. Troubled Debt Restructurings The following table summarizes information for troubled debt restructurings (TDRs): (Dollars in thousands) At June 30, At December 31, 2017 Accrual status $ 150,459 $ 147,113 Non-accrual status 79,515 74,291 Total recorded investment of TDRs $ 229,974 $ 221,404 Specific reserves for TDRs included in the balance of ALLL $ 11,334 $ 12,384 Additional funds committed to borrowers in TDR status 7,206 2,736 For the portion of TDRs deemed to be uncollectible, Webster charged off $4.5 million and $0.6 million for the three months ended June 30, 2018 and 2017 , respectively, and $5.2 million , and $2.6 million for the six months ended June 30, 2018 and 2017 , respectively. The following table provides information on the type of concession for loans and leases modified as TDRs: Three months ended June 30, Six months ended June 30, 2018 2017 2018 2017 Number of Post- (1) Number of Post- (1) Number of Post- (1) Number of Post- (1) (Dollars in thousands) Residential Extended Maturity — $ — 4 $ 420 — $ — 9 $ 1,390 Adjusted Interest Rate — — 2 335 — — 2 335 Maturity/Rate Combined 3 276 2 354 3 276 5 846 Other (2) 8 1,685 7 1,176 13 2,442 26 4,114 Consumer - home equity Extended Maturity — — 4 625 2 193 6 664 Adjusted Interest Rate — — — — — — — — Maturity/Rate Combined 1 335 4 830 3 448 11 2,813 Other (2) 14 915 10 701 25 1,693 43 2,894 Commercial non - mortgage Extended Maturity — — 6 778 3 85 8 813 Adjusted Interest Rate — — — — — — — — Maturity/Rate Combined 2 51 5 8,854 2 51 5 8,854 Other (2) 7 24,059 — — 9 28,743 1 4 Commercial real estate Extended Maturity 1 52 — — 2 97 — — Maturity/Rate Combined 1 245 — — 1 245 — — Other (2) 1 5,111 — — 1 5,111 — — Equipment Financing Extended Maturity — — — — — — — — Total TDRs 38 $ 32,729 44 $ 14,073 64 $ 39,384 116 $ 22,727 (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. There were no significant amounts of loans and leases modified as TDRs within the previous 12 months and for which there was a payment default during the three and six months ended June 30, 2018 or 2017 . The recorded investment of TDRs in commercial, commercial real estate, and equipment financing segregated by risk rating exposure is as follows: (In thousands) At June 30, 2018 At December 31, 2017 (1) - (6) Pass $ 3,886 $ 8,268 (7) Special Mention 14,109 355 (8) Substandard 60,706 53,050 (9) Doubtful — — Total $ 78,701 $ 61,673

Transfers of Financial Assets

Transfers of Financial Assets	6 Months Ended
	Jun. 30, 2018
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. Gains and losses from initial measurement and subsequent changes in fair value are recognized in earnings. The gain or loss on residential mortgage loans sold and the related origination fee income, as well as fair value adjustments to loans held-for-sale are included as mortgage banking activities in the accompanying 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 June 30, Six months ended June 30, (In thousands) 2018 2017 2018 2017 Beginning balance $ 664 $ 824 $ 872 $ 790 Provision (benefit) charged to expense 13 19 (190 ) 53 Repurchased loans and settlements charged off (3 ) — (8 ) — Ending balance $ 674 $ 843 $ 674 $ 843 The following table provides information for mortgage banking activities: Three months ended June 30, Six months ended June 30, (In thousands) 2018 2017 2018 2017 Residential mortgage loans held for sale: Proceeds from sale $ 45,257 $ 66,718 $ 90,063 $ 173,338 Loans sold with servicing rights retained 39,822 60,167 79,726 159,667 Net gain on sale 598 2,126 1,681 2,377 Ancillary fees 402 641 812 1,409 Fair value option adjustment 235 584 (114 ) 1,831 The Company has retained servicing rights on residential mortgage loans totaling $2.5 billion at June 30, 2018 and $2.6 billion at December 31, 2017 . The following table presents the changes in carrying value for mortgage servicing assets: Three months ended June 30, Six months ended June 30, (In thousands) 2018 2017 2018 2017 Beginning balance $ 24,403 $ 24,336 $ 25,139 $ 24,466 Additions 1,038 2,478 2,450 4,487 Amortization (2,100 ) (2,106 ) (4,248 ) (4,245 ) Ending balance $ 23,341 $ 24,708 $ 23,341 $ 24,708 Loan servicing fees, net of mortgage servicing rights amortization, were $0.3 million and $0.2 million for the three months ended June 30, 2018 and 2017 , respectively, and $0.6 million and $0.4 million for the six months ended June 30, 2018 and 2017 , 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 additional fair value information on loans held for sale and mortgage servicing assets. Additionally, loans not originated for sale were sold approximately at carrying value, for cash proceeds of $34 thousand for certain commercial loans and $7.4 million for certain residential loans for the six months ended June 30, 2018 and 2017

Goodwill and Other Intangible A

Goodwill and Other Intangible Assets	6 Months Ended
	Jun. 30, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Other Intangible Assets	Goodwill and Other Intangible Assets Goodwill and other intangible assets by reportable segment consisted of the following: At June 30, 2018 At December 31, 2017 (In thousands) Gross Carrying Amount Accumulated Amortization Net Carrying Amount Gross Carrying Amount Accumulated Amortization Net Carrying Amount Goodwill: Community Banking $ 516,560 $ 516,560 HSA Bank 21,813 21,813 Total goodwill $ 538,373 $ 538,373 Other intangible assets: HSA Bank - Core deposits $ 22,000 $ (9,725 ) $ 12,275 $ 22,000 $ (8,610 ) $ 13,390 HSA Bank - Customer relationships 21,000 (5,587 ) 15,413 21,000 (4,779 ) 16,221 Total other intangible assets $ 43,000 $ (15,312 ) $ 27,688 $ 43,000 $ (13,389 ) $ 29,611 As of June 30, 2018 , the remaining estimated aggregate future amortization expense for intangible assets is as follows: (In thousands) Remainder of 2018 $ 1,924 2019 3,847 2020 3,847 2021 3,847 2022 3,847 Thereafter 10,376

Deposits

Deposits	6 Months Ended
	Jun. 30, 2018
Banking and Thrift [Abstract]
Deposits	A summary of deposits by type follows: (In thousands) At June 30, At December 31, Non-interest-bearing: Demand $ 4,151,259 $ 4,191,496 Interest-bearing: Health savings accounts 5,517,929 5,038,681 Checking 2,637,346 2,736,952 Money market 2,016,453 2,209,492 Savings 4,180,666 4,348,700 Time deposits 2,839,703 2,468,408 Total interest-bearing 17,192,097 16,802,233 Total deposits $ 21,343,356 $ 20,993,729 Time deposits and interest-bearing checking, included in above balances, obtained through brokers $ 936,830 $ 898,157 Time deposits, included in above balance, that meet or exceed the FDIC limit 888,419 561,512 Deposit overdrafts reclassified as loan balances 3,587 2,210 The scheduled maturities of time deposits are as follows: (In thousands) At June 30, Remainder of 2018 $ 1,016,354 2019 1,313,184 2020 314,856 2021 122,427 2022 47,641 Thereafter 25,241 Total time deposits $ 2,839,703

Borrowings

Borrowings	6 Months Ended
	Jun. 30, 2018
Debt Disclosure [Abstract]
Borrowings	Borrowings Total borrowings of $2.7 billion at June 30, 2018 and $2.5 billion at December 31, 2017 are described in detail below. The following table summarizes securities sold under agreements to repurchase and other borrowings: At June 30, At December 31, (In thousands) Amount Rate Amount Rate Securities sold under agreements to repurchase (1) : Original maturity of one year or less $ 257,568 0.25 % $ 288,269 0.17 % Original maturity of greater than one year, non-callable 300,000 3.10 300,000 3.10 Total securities sold under agreements to repurchase 557,568 1.78 588,269 1.66 Fed funds purchased 305,000 1.99 55,000 1.37 Securities sold under agreements to repurchase and other borrowings $ 862,568 1.86 $ 643,269 1.64 (1) The Company has right of offset with respect to all repurchase agreement assets and liabilities. However, securities sold under agreements to repurchase represents the gross amount for these transactions, as only liabilities are outstanding for the periods presented. 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 or municipal customers through Webster’s Treasury Unit. The following table provides information for FHLB advances: At June 30, At December 31, (Dollars in thousands) Amount Weighted- Average Contractual Coupon Rate Amount Weighted- Average Contractual Coupon Rate Maturing within 1 year $ 1,075,000 1.99 % $ 1,150,000 1.48 % After 1 but within 2 years 153,026 1.78 103,026 1.81 After 2 but within 3 years 190,000 1.71 215,000 1.73 After 3 but within 4 years 150,000 3.24 200,000 2.06 (1) After 4 but within 5 years 160 — 170 — After 5 years 8,770 2.65 8,909 2.65 (1) FHLB advances and overall rate $ 1,576,956 2.06 $ 1,677,105 1.61 (1) Aggregate carrying value of assets pledged as collateral $ 6,216,042 $ 6,402,066 Remaining borrowing capacity 2,610,327 2,600,624 (1) Weighted-average contractual coupon rates for December 31, 2017 are presented as revised for these classifications to correct an immaterial error in presentation. The percentages reported in the Company's 2017 Annual Report on Form 10-K were: After 3 but within 4 years - 4.13% ; After 5 years - 1.96% ; and overall rate - 1.85% . Webster Bank 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 June 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 (667 ) (727 ) Debt issuance cost on senior fixed-rate notes (759 ) (826 ) Long-term debt $ 225,894 $ 225,767 (1) The interest rate on Webster Statutory Trust I floating-rate notes, which varies quarterly based on 3-month London Interbank Offered Rate plus 2.95% , was 5.28% at June 30, 2018 and 4.55% at December 31, 2017

Accumulated Other Comprehensive

Accumulated Other Comprehensive Loss, Net of Tax	6 Months Ended
	Jun. 30, 2018
Equity [Abstract]
Accumulated Other Comprehensive Loss, Net of Tax	Accumulated Other Comprehensive Loss, Net of Tax The following tables summarize the changes in accumulated other comprehensive loss, net of tax (AOCL) by component: Three months ended June 30, 2018 Six months ended June 30, 2018 (In thousands) Securities Available For Sale Derivative Instruments Defined Benefit Pension and Other Postretirement Benefit Plans Total Securities Available For Sale Derivative Instruments Defined Benefit Pension and Other Postretirement Benefit Plans Total Beginning balance $ (55,371 ) $ (12,494 ) $ (47,614 ) $ (115,479 ) $ (27,947 ) $ (15,016 ) $ (48,568 ) $ (91,531 ) (OCL) OCI before reclassifications (9,246 ) 294 — (8,952 ) (36,670 ) 1,423 — (35,247 ) Amounts reclassified from AOCL — 1,386 1,109 2,495 — 2,779 2,063 4,842 Net current-period OCI/(OCL) (9,246 ) 1,680 1,109 (6,457 ) (36,670 ) 4,202 2,063 (30,405 ) Ending balance $ (64,617 ) $ (10,814 ) $ (46,505 ) $ (121,936 ) $ (64,617 ) $ (10,814 ) $ (46,505 ) $ (121,936 ) Three months ended June 30, 2017 Six months ended June 30, 2017 (In thousands) Securities Available For Sale Derivative Instruments Defined Benefit Pension and Other Postretirement Benefit Plans Total Securities Available For Sale Derivative Instruments Defined Benefit Pension and Other Postretirement Benefit Plans Total Beginning balance $ (17,701 ) $ (15,909 ) $ (43,417 ) $ (77,027 ) $ (15,476 ) $ (17,068 ) $ (44,449 ) $ (76,993 ) OCI/(OCL) before reclassifications 3,200 (472 ) — 2,728 975 (411 ) — 564 Amounts reclassified from AOCL — 1,123 1,094 2,217 — 2,221 2,126 4,347 Net current-period OCI 3,200 651 1,094 4,945 975 1,810 2,126 4,911 Ending balance $ (14,501 ) $ (15,258 ) $ (42,323 ) $ (72,082 ) $ (14,501 ) $ (15,258 ) $ (42,323 ) $ (72,082 ) The following tables provide information for the items reclassified from AOCL: (In thousands) Three months ended June 30, Six months ended June 30, Associated Line Item in the Condensed Consolidated Statements of Income AOCL Components 2018 2017 2018 2017 Derivative instruments: Cash flow hedges $ (1,861 ) $ (1,771 ) $ (3,732 ) $ (3,506 ) Total interest expense Tax benefit 475 648 953 1,285 Income tax expense Net of tax $ (1,386 ) $ (1,123 ) $ (2,779 ) $ (2,221 ) Defined benefit pension and other postretirement benefit plans: Amortization of net loss $ (1,493 ) $ (1,734 ) $ (2,778 ) $ (3,372 ) (1) Tax benefit 384 640 715 1,246 Income tax expense Net of tax $ (1,109 ) $ (1,094 ) $ (2,063 ) $ (2,126 )

Regulatory Matters

Regulatory Matters	6 Months Ended
	Jun. 30, 2018
Regulatory Capital Requirements [Abstract]
Regulatory Matters	Regulatory Matters Capital Requirements Webster Financial Corporation is subject to regulatory capital requirements administered by the Federal Reserve System, while Webster Bank is subject to regulatory capital requirements administered by the Office of the Comptroller of the Currency (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 adjustments. 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 June 30, 2018 Actual Minimum Requirement Well Capitalized (Dollars in thousands) Amount Ratio Amount Ratio Amount Ratio Webster Financial Corporation CET1 risk-based capital $ 2,148,786 10.99 % $ 879,461 4.5 % $ 1,270,333 6.5 % Total risk-based capital 2,581,061 13.21 1,563,486 8.0 1,954,358 10.0 Tier 1 risk-based capital 2,293,823 11.74 1,172,615 6.0 1,563,486 8.0 Tier 1 leverage capital 2,293,823 8.70 1,054,648 4.0 1,318,310 5.0 Webster Bank CET1 risk-based capital $ 2,100,537 10.76 % $ 878,786 4.5 % $ 1,269,357 6.5 % Total risk-based capital 2,310,455 11.83 1,562,285 8.0 1,952,857 10.0 Tier 1 risk-based capital 2,100,537 10.76 1,171,714 6.0 1,562,285 8.0 Tier 1 leverage capital 2,100,537 7.97 1,054,035 4.0 1,317,543 5.0 At December 31, 2017 Actual Minimum Requirement Well Capitalized (Dollars in thousands) Amount Ratio Amount Ratio Amount Ratio Webster Financial Corporation CET1 risk-based capital $ 2,093,116 11.14 % $ 845,389 4.5 % $ 1,221,118 6.5 % Total risk-based capital 2,517,848 13.40 1,502,914 8.0 1,878,643 10.0 Tier 1 risk-based capital 2,238,172 11.91 1,127,186 6.0 1,502,914 8.0 Tier 1 leverage capital 2,238,172 8.63 1,036,817 4.0 1,296,021 5.0 Webster Bank CET1 risk-based capital $ 2,114,224 11.26 % $ 844,693 4.5 % $ 1,220,113 6.5 % Total risk-based capital 2,316,580 12.34 1,501,677 8.0 1,877,097 10.0 Tier 1 risk-based capital 2,114,224 11.26 1,126,258 6.0 1,501,677 8.0 Tier 1 leverage capital 2,114,224 8.14 1,038,442 4.0 1,298,052 5.0 Dividend Restrictions Webster Financial Corporation is dependent upon dividends from Webster Bank to provide funds for its cash requirements, including payments of dividends to shareholders. Banking regulations may limit the amount of dividends that may be paid. Approval by regulatory authorities is required if the effect of dividends declared would cause the regulatory capital of Webster Bank to fall below specified minimum levels, or if dividends declared exceed the net income for that year combined with the undistributed net income for the preceding two years. In addition, the Office of the Comptroller of the Currency (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 $150 million during the six months ended June 30, 2018 compared to $30 million during the six months ended June 30, 2017 . 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 $89.0 million and $82.3 million at June 30, 2018 and December 31, 2017

Earnings Per Common Share

Earnings Per Common Share	6 Months Ended
	Jun. 30, 2018
Earnings Per Share [Abstract]
Earnings Per Common Share	Earnings Per Common Share Reconciliation of the calculation of basic and diluted earnings per common share follows: Three Months Ended June 30, Six Months Ended June 30, (In thousands, except per share data) 2018 2017 2018 2017 Earnings for basic and diluted earnings per common share: Net income $ 81,682 $ 61,579 $ 161,907 $ 121,050 Less: Preferred stock dividends 1,969 2,024 3,916 4,048 Net income available to common shareholders 79,713 59,555 157,991 117,002 Less: Earnings applicable to participating securities 224 70 418 176 Earnings applicable to common shareholders $ 79,489 $ 59,485 $ 157,573 $ 116,826 Shares: Weighted-average common shares outstanding - basic 91,893 92,092 91,913 91,989 Effect of dilutive securities: Stock options and restricted stock 274 397 317 475 Warrants 6 6 6 6 Weighted-average common shares outstanding - diluted 92,173 92,495 92,236 92,470 Earnings per common share: Basic $ 0.87 $ 0.65 $ 1.71 $ 1.27 Diluted 0.86 0.64 1.71 1.26 Potential common shares from non-participating restricted stock, of $53 thousand and $79 thousand for the three months ended June 30, 2018 and 2017 , respectively, and $61 thousand and $60 thousand for the six months ended June 30, 2018 and 2017 , respectively, are excluded from the effect of dilutive securities because, due to performance conditions, they would have been anti-dilutive.

Derivative Financial Instrument

Derivative Financial Instruments	6 Months Ended
	Jun. 30, 2018
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, which results in minimal impact on earnings, except for fee income earned in such transactions. All contracts eligible for clearing are cleared through Chicago Mercantile Exchange (CME). In accordance with its amended rulebook, CME legally characterizes variation margin payments made to and received from CME as settlement of derivatives rather than as collateral against derivatives. Risk participation agreements (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 and customer hedging activity, a VISA equity swap transaction, and mortgage banking derivatives such as mortgage-backed securities related to residential loan commitments and loans held for sale. Mortgage banking derivatives are utilized by Webster in its efforts to manage risk of loss associated with its mortgage loan commitments and mortgage loans held for sale. Prior to closing and funding certain single-family residential mortgage loans interest rate lock commitments are generally extended to the borrowers. During the period from commitment date to closing date, Webster is subject to the risk that market rates of interest may change. If market rates rise, investors generally will pay less to purchase such loans causing a reduction in the anticipated gain on sale of the loans, 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. Balance Sheet Impact of Derivative Instruments The following table presents the notional amounts and fair value of derivative positions: At June 30, 2018 At December 31, 2017 Asset Derivatives Liability Derivatives Asset Derivatives Liability Derivatives (In thousands) Notional Fair Notional Fair Notional Fair Notional Fair Designated as cash flow hedging instruments: Positions subject to a master netting agreement (1) Interest rate derivatives (2) $ 325,000 $ 4,685 $ — $ — $ 325,000 $ 2,770 $ — $ — Not designated as hedging instruments: Positions subject to a master netting agreement (1) Interest rate derivatives (2) 3,523,220 12,286 198,836 321 2,791,760 5,977 721,048 1,968 Mortgage banking derivatives (3) 41,718 441 32,053 199 28,497 421 39,230 110 Other 29,571 629 38,224 485 7,914 258 30,328 419 Positions not subject to a master netting agreement (4) Interest rate derivatives 666,149 6,987 3,055,950 71,057 1,366,299 23,009 2,146,518 25,631 RPAs 85,164 26 95,340 58 93,713 80 116,882 111 Other 8,615 240 422 17 — — 2,073 184 Total not designated as hedging instruments 4,354,437 20,609 3,420,825 72,137 4,288,183 29,745 3,056,079 28,423 Gross derivative instruments, before netting $ 4,679,437 25,294 $ 3,420,825 72,137 $ 4,613,183 32,515 $ 3,056,079 28,423 Less: Legally enforceable master netting agreements 729 729 2,245 2,245 Less: Cash collateral posted 16,791 — 6,704 — Total derivative instruments, after netting $ 7,774 $ 71,408 $ 23,566 $ 26,178 (1) The Company has elected to report derivative positions subject to a legally enforceable master netting agreement on a net basis, net of cash collateral. Refer to the Offsetting Derivatives section of this footnote for additional information. (2) Balances related to CME are presented as a single unit of account. Notional amounts of interest rate swaps cleared through CME include; $2.5 billion and $1.9 billion for asset derivatives and $171 million and $595 million for liability derivatives at June 30, 2018 and December 31, 2017, respectively, with related fair values of approximately zero . (3) Notional amounts include mandatory forward commitments of $41.0 million , while notional amounts do not include approved floating rate commitments of $14.9 million , at June 30, 2018 . (4) Fair value of assets are included in accrued interest receivable and other assets, while, fair value of liabilities are included in accrued expenses and other liabilities, in the accompanying Condensed Consolidated Balance Sheets. Income Statement Impact of Derivative Instruments The following table presents the effect on the income statement from derivative positions: Three months ended June 30, Six months ended June 30, (In thousands) 2018 2017 2018 2017 Designated as cash flow hedging instruments: Interest rate derivatives (1) $ 1,668 $ 1,986 $ 3,491 $ 4,025 Not designated as hedging instruments: Interest rate derivatives (2) $ 1,958 $ 1,361 $ 5,749 $ 2,895 RPAs 85 53 95 106 Mortgage banking derivatives (134 ) 374 (69 ) (1,667 ) Other (2) 1,939 (545 ) 1,339 (992 ) Total not designated as hedging instruments (2) (3) $ 3,848 $ 1,243 $ 7,114 $ 342 (1) The impact from interest rate derivatives designated as hedging instruments is included in interest expense on borrowings in the accompanying Condensed Consolidated Statements of Income. (2) Amounts for 2017 are presented as revised to include impact on accrued interest for net customer swap arrangements. (3) The impact from the total not designated as hedging instruments is included in other non-interest income in the accompanying Condensed Consolidated Statements of Income. Amounts for the effective portion of changes in the fair value of derivatives qualifying for hedge accounting treatment are reclassified to interest expense as interest payments are made on Webster's variable-rate debt. Over the next twelve months, the Company estimates that $109 thousand will be reclassified from AOCL as an increase to interest income. Webster records gains and losses related to hedge terminations to AOCL. These balances are subsequently amortized into interest expense over the respective terms of the hedged debt instruments. At June 30, 2018 , the remaining unamortized loss on the termination of cash flow hedges is $11.7 million . Over the next twelve months, the Company estimates that $5.0 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 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 presents the transition from a gross basis to net basis, due to the application of counterparty netting agreements: At June 30, 2018 At December 31, 2017 (In thousands) Gross Amount Relationship Offset Cash Collateral Offset Net Amount Gross Amount Relationship Offset Cash Collateral Offset Net Amount Derivative instrument gains: Hedge accounting $ 4,685 $ — $ 4,685 $ — $ 2,770 $ 91 $ 2,679 $ — Non-hedge accounting 12,915 729 12,106 80 6,222 2,154 4,025 43 Total assets $ 17,600 $ 729 $ 16,791 $ 80 $ 8,992 $ 2,245 $ 6,704 $ 43 Derivative instrument losses: Hedge accounting $ — $ — $ — $ — $ — $ — $ — $ — Non-hedge accounting 806 729 — 77 2,387 2,245 — 142 Total liabilities $ 806 $ 729 $ — $ 77 $ 2,387 $ 2,245 $ — $ 142 Counterparty Credit Risk Use of derivative contracts may expose Webster Bank to counterparty credit risk. The Company has International Swaps and Derivatives Association Master Agreements, including a Credit Support Annex, with all derivative counterparties. In accordance with counterparty credit agreements and derivative clearing rules, the Company had approximately $66.6 million in net margin collateral received from financial counterparties at June 30, 2018 , comprised of $34.5 million in initial margin posted and $101.1 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. Credit risk exposure is mitigated as transactions with customers are generally secured by the same collateral of the underlying transactions being hedged. The Company's net current credit exposure relating to interest rate derivatives with Webster Bank customers was $7.0 million at June 30, 2018 . In addition, the Company monitors potential future exposure, representing its best estimate of exposure to remaining contractual maturity. The potential future exposure relating to interest rate derivatives with Webster Bank customers totaled $30.2 million at June 30, 2018

Fair Value Measurements

Fair Value Measurements	6 Months Ended
	Jun. 30, 2018
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements Fair value is the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. Fair value is best determined using quoted market prices. However, in many instances, quoted market prices are not available. In such instances, fair values are determined using appropriate valuation techniques. Various assumptions and observable inputs must be relied upon in applying these techniques. Accordingly, categorization within the valuation hierarchy is based upon the lowest level of input that is significant to the fair value measurement. As such, the fair value estimates may not be realized in an immediate transfer of the respective asset or liability. Fair value estimates are made at a specific point in time, based on relevant market information and information about the financial instrument. These estimates do not reflect any premium or discount that could result from offering for sale at one time the entire holdings or any part of a particular financial instrument. Fair value estimates are based on judgments regarding future expected loss experience, current economic conditions, risk characteristics of various financial instruments, and other factors. These factors are subjective in nature and involve uncertainties and matters of significant judgment and, therefore, cannot be determined with precision. Changes in assumptions could significantly affect the estimates. Fair Value Hierarchy The three levels within the fair value hierarchy are as follows: • Level 1: Valuation is based upon unadjusted quoted prices in active markets for identical assets or liabilities that the reporting entity has the ability to access at the measurement date. • Level 2: Fair value is calculated using significant inputs other than quoted market prices that are directly or indirectly observable for the asset or liability. The valuation may rely on quoted prices for similar assets or liabilities in active markets, quoted prices for identical or similar assets or liabilities in inactive markets, inputs other than quoted prices that are observable for the asset or liability (such as interest rates, volatilities, prepayment speeds, credit ratings, etc.), or inputs that are derived principally or corroborated by market data, by correlation, or other means. • Level 3: Inputs for determining the fair value of the respective assets or liabilities are not observable. Level 3 valuations are reliant upon pricing models and techniques that require significant management judgment or estimation. Assets and Liabilities Measured at Fair Value on a Recurring Basis Available-for-Sale Investment Securities. When quoted prices are available in an active market, the Company classifies investment securities within Level 1 of the valuation hierarchy. U.S. Treasury Bills are classified within Level 1 of the fair value hierarchy. When quoted market prices are not available, the Company employs an independent pricing service that utilizes matrix pricing to calculate fair value. Such fair value measurements consider observable data such as dealer quotes, market spreads, cash flows, yield curves, live trading levels, trade execution data, market consensus prepayments speeds, credit information, and respective terms and conditions for debt instruments. Management maintains procedures to monitor the pricing service's results and establishes processes to challenge their valuations, or methodology, that appear unusual or unexpected. Available-for-Sale investment securities which include Agency CMO, Agency MBS, Agency CMBS, CMBS, CLO, and corporate debt, are classified within Level 2 of the fair value hierarchy. Derivative Instruments. Foreign exchange contracts are valued based on unadjusted quoted prices in active markets and classified within Level 1 of the fair value hierarchy. All other derivative instruments are valued using third-party valuation software, which considers the present value of cash flows discounted using observable forward rate assumptions. The resulting fair values are validated against valuations performed by independent third parties and are classified within Level 2 of the fair value hierarchy. In determining if any fair value adjustment related to credit risk is required, Webster evaluates the credit risk of its counterparties by considering factors such as the likelihood of default by the counterparties, its net exposures, the remaining contractual life, as well as the amount of collateral securing the position. Webster reviews its counterparty exposure on a regular basis, and, when necessary, appropriate business actions are taken to mitigate the exposure. When determining fair value, Webster applies the portfolio exception with respect to measuring counterparty credit risk for all of its derivative transactions subject to a master netting arrangement. The CME rulebook legally characterizes variation margin payments for over-the-counter derivatives as settlements rather than collateral, which impacts Webster's counterparty relationship with CME, resulting in the fair value of the instrument including cash collateral to be represented as a single unit of account. 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 into issuances of mortgage-backed securities. The fair value of mortgage banking derivatives is determined based on current market prices for similar assets in the secondary market and, therefore, classified within Level 2 of the fair value hierarchy. Originated Loans Held For Sale. Residential mortgage loans typically are classified as held for sale upon origination based on management's intent to sell such loans. The Company has elected to measure originated loans held for sale under the fair value option of Accounting Standards Codification ( ASC) Topic 825 "Financial Instruments," on a loan-by-loan basis. 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, these loans are classified within Level 2 of the fair value hierarchy. The following table presents the fair value, unpaid principal balance, and accrual status, of assets accounted for under the fair value option: At June 30, 2018 At December 31, 2017 (In thousands) Fair Value Unpaid Principal Balance Difference Fair Value Unpaid Principal Balance Difference Originated loans held for sale $ 18,645 $ 18,234 $ 411 $ 20,888 $ 20,346 $ 542 Electing to measure originated loans held for sale at fair value reduces certain timing differences and better matches changes in the value of these assets with changes in the value of the derivatives used as an economic hedge on these assets. Investments Held in Rabbi Trust. Investments held in the Rabbi Trust primarily include mutual funds that invest in equity and fixed income securities. Shares of mutual funds are valued based on net asset value, which represents quoted market prices for the underlying shares held in the mutual funds. Therefore, investments held in the Rabbi Trust are classified within Level 1 of the fair value hierarchy. Webster has elected to measure the investments held in the Rabbi Trust at fair value. The cost basis of the investments held in the Rabbi Trust is $2.0 million at June 30, 2018 . Alternative Investments. Equity investments have a readily determinable fair value when quoted prices are available in an active market. The Company classifies alternative investments with a readily determinable fair value within Level 1 of the fair value hierarchy. Equity investments that do not have a readily available fair value may qualify for net asset value (NAV) measurement based on specific requirements. The Company's alternative investments accounted for at NAV consist of investments in non-public entities that generally cannot be redeemed since the Company’s investments are distributed as the underlying equity is liquidated. Alternative investments recorded at NAV are not classified within the fair value hierarchy. At June 30, 2018 , these alternative investments had a remaining unfunded commitment of $0.3 million . Summaries of the fair values of assets and liabilities measured at fair value on a recurring basis are as follows: At June 30, 2018 (In thousands) Level 1 Level 2 Level 3 NAV Total Financial assets held at fair value: U.S. Treasury Bills $ 2,491 $ — $ — $ — $ 2,491 Agency CMO — 265,253 — — 265,253 Agency MBS — 1,311,841 — — 1,311,841 Agency CMBS — 582,676 — — 582,676 CMBS — 374,556 — — 374,556 CLO — 188,066 — — 188,066 Single issuer-trust preferred — — — — — Corporate debt — 55,698 — — 55,698 Total available-for-sale investment securities 2,491 2,778,090 — — 2,780,581 Gross derivative instruments, before netting (1) 869 24,425 — — 25,294 Originated loans held for sale — 18,645 — — 18,645 Investments held in Rabbi Trust 4,726 — — — 4,726 Alternative investments 2,439 — — 1,895 4,334 Total financial assets held at fair value $ 10,525 $ 2,821,160 $ — $ 1,895 $ 2,833,580 Financial liabilities held at fair value: Gross derivative instruments, before netting (1) $ 485 $ 71,652 $ — $ — $ 72,137 At December 31, 2017 (In thousands) Level 1 Level 2 Level 3 NAV Total Financial assets held at fair value: U.S. Treasury Bills $ 1,247 $ — $ — $ — $ 1,247 Agency CMO — 306,333 — — 306,333 Agency MBS — 1,107,841 — — 1,107,841 Agency CMBS — 588,026 — — 588,026 CMBS — 361,067 — — 361,067 CLO — 209,851 — — 209,851 Single issuer-trust preferred — 7,050 — — 7,050 Corporate debt — 56,622 — — 56,622 Total available-for-sale investment securities 1,247 2,636,790 — — 2,638,037 Gross derivative instruments, before netting (1) 258 32,257 — — 32,515 Originated loans held for sale — 20,888 — — 20,888 Investments held in Rabbi Trust 4,801 — — — 4,801 Alternative investments — — — 3,495 3,495 Total financial assets held at fair value $ 6,306 $ 2,689,935 $ — $ 3,495 $ 2,699,736 Financial liabilities held at fair value: Gross derivative instruments, before netting (1) $ 587 $ 27,836 $ — $ — $ 28,423 (1) For information relating to the impact of netting derivative assets and derivative liabilities as well as the impact from offsetting cash collateral paid to the same derivative counterparties see Note 12: Derivative Financial Instruments . Assets Measured at Fair Value on a Non-Recurring Basis Certain assets are measured at fair value on a non-recurring basis; that is, the assets are not measured at fair value on an ongoing basis but are subject to fair value adjustments in certain circumstances, for example, when there is evidence of impairment. The following is a description of valuation methodologies used for assets measured on a non-recurring basis. Alternative Investments. The measurement alternative has been elected for alternative investments without readily determinable fair values that do not qualify for the NAV practical expedient. The measurement alternative requires investments to be accounted for at cost minus impairment, if any, plus or minus changes resulting from observable price changes in orderly transactions for the identical or a similar investment of the same issuer. These alternative investments are investments in non-public entities that generally cannot be redeemed since the investment is distributed as the underlying equity is liquidated. Accordingly, these alternative investments are classified within Level 2 of the fair value hierarchy. The carrying amount of these alternative investments was $2.5 million at June 30, 2018 . No reduction for impairments, or increase or decrease due to observable price changes, was identified during the three or six months ended June 30, 2018 . Transferred Loans Held For Sale. Certain loans are transferred to loans held for sale once a decision has been made to sell such loans. These loans are accounted for at the lower of cost or market and are considered to be recognized at fair value when they are recorded at below cost. This activity 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 other real estate owned (OREO) and repossessed assets was $6.0 million at June 30, 2018 . OREO and repossessed assets are accounted for at the lower of cost or market and are considered to be recognized at fair value when they are recorded at below cost. The fair value of OREO is based on independent appraisals or internal valuation methods, less estimated selling costs. The valuation may consider available pricing guides, auction results, and price opinions. Certain assets require assumptions about factors that are not observable in an active market in the determination of fair value; as such, OREO and repossessed assets are classified within Level 3 of the fair value hierarchy. The table below presents the valuation methodology and unobservable inputs for Level 3 assets measured at fair value on a non-recurring basis as of June 30, 2018 : (Dollars in thousands) Asset Fair Value Valuation Methodology Unobservable Inputs Range of Inputs Collateral dependent impaired loans and leases $ 15,414 Real Estate Appraisals Discount for appraisal type 0% - 15% Discount for costs to sell 0% - 8% OREO $ 467 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, as well as servicing assets. The following is a description of valuation methodologies used for those assets and liabilities. Cash, Due from Banks, and Interest-bearing Deposits. The carrying amount of cash, due from banks, and interest-bearing deposits is used to approximate fair value, given the short time frame to maturity and, as such, these assets do not present unanticipated credit concerns. Cash, due from banks, and interest-bearing deposits are classified within Level 1 of the fair value hierarchy. Held-to-Maturity Investment Securities. When quoted market prices are not available, the Company employs an independent pricing service that utilizes matrix pricing to calculate fair value. Such fair value measurements consider observable data such as dealer quotes, market spreads, cash flows, yield curves, live trading levels, trade execution data, market consensus prepayments speeds, credit information, and respective terms and conditions for debt instruments. Management maintains procedures to monitor the pricing service's results and establishes processes to challenge their valuations, or methodology, that appear unusual or unexpected. Held-to-Maturity investment securities, which include Agency CMO, Agency MBS, Agency CMBS, CMBS, municipal bonds and notes, and private label MBS securities, are classified within Level 2 of the fair value hierarchy. Loans and Leases, net. The estimated fair value of loans and leases held for investment is calculated using a discounted cash flow method, using future prepayments and market interest rates inclusive of an illiquidity premium for comparable loans and leases. The associated cash flows are adjusted for credit and other potential losses. Fair value for impaired loans and leases is estimated using the net present value of the expected cash flows. Loans and leases are classified within Level 3 of the fair value hierarchy. Deposit Liabilities. The fair value of demand deposits, savings accounts, and certain money market deposits is the amount payable on demand at the reporting date. Deposit liabilities are classified within Level 2 of the fair value hierarchy. Time Deposits. The fair value of a fixed-maturity certificate of deposit is estimated using the rates currently offered for deposits of similar remaining maturities. Time deposits are classified within Level 2 of the fair value hierarchy. Securities Sold Under Agreements to Repurchase and Other Borrowings. The carrying value is an estimate of fair value for those securities sold under agreements to repurchase and other borrowings that mature within 90 days. Fair value of all other borrowings is estimated using discounted cash flow analysis based on current market rates adjusted, as appropriate, for associated credit risks. Securities sold under agreements to repurchase and other borrowings are classified within Level 2 of the fair value hierarchy. Federal Home Loan Bank Advances and Long-Term Debt. The fair value of FHLB advances and long-term debt is estimated using a discounted cash flow technique. Discount rates are matched with the time period of the expected cash flow and are adjusted, as appropriate, to reflect credit risk. FHLB advances and long-term debt are classified within Level 2 of the fair value hierarchy. Mortgage Servicing Assets. Mortgage servicing assets are accounted for at cost, 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 June 30, 2018 At December 31, 2017 (In thousands) Carrying Amount Fair Value Carrying Amount Fair Value Assets: Level 2 Held-to-maturity investment securities $ 4,356,219 $ 4,225,983 $ 4,487,392 $ 4,456,350 Level 3 Loans and leases, net 17,818,674 17,642,617 17,323,864 17,211,619 Mortgage servicing assets 23,341 49,182 25,139 45,309 Liabilities: Level 2 Deposit liabilities $ 18,503,653 $ 18,503,653 $ 18,525,321 $ 18,525,321 Time deposits 2,839,703 2,811,645 2,468,408 2,455,245 Securities sold under agreements to repurchase and other borrowings 862,568 862,371 643,269 644,084 FHLB advances 1,576,956 1,576,797 1,677,105 1,678,070 Long-term debt (1) 225,894 230,223 225,767 234,359 (1) Adjustments to the carrying amount of long-term debt for unamortized discount and debt issuance cost on senior fixed-rate notes are not included for determination of fair value, see Note 8: Borrowings

Retirement Benefit Plans

Retirement Benefit Plans	6 Months Ended
	Jun. 30, 2018
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 June 30, 2018 2017 (In thousands) Pension Plan SERP Other Benefits Pension Plan SERP Other Benefits Service cost $ — $ — $ — $ 13 $ — $ — Interest cost on benefit obligations 1,935 (21 ) 19 1,844 93 25 Expected return on plan assets (3,180 ) — — (3,075 ) — — Amortization of prior service cost — — — — — — Recognized net loss 1,160 333 — 1,515 212 7 Net periodic benefit cost $ (85 ) $ 312 $ 19 $ 297 $ 305 $ 32 Six months ended June 30, 2018 2017 (In thousands) Pension Plan SERP Other Benefits Pension Plan SERP Other Benefits Service cost $ — $ — $ — $ 25 $ — $ — Interest cost on benefit obligations 3,720 166 39 3,657 185 50 Expected return on plan assets (6,360 ) — — (6,148 ) — — Amortization of prior service cost — — — — — — Recognized net loss 2,320 458 — 2,932 425 15 Net periodic benefit cost $ (320 ) $ 624 $ 39 $ 466 $ 610 $ 65

Share-Based Plans

Share-Based Plans	6 Months Ended
	Jun. 30, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Share-Based Plans	Share-Based Plans Stock compensation plans Webster maintains stock compensation plans under which restricted stock, restricted stock units, non-qualified stock options, incentive stock options, or stock appreciation rights may be granted to employees and directors. The Company believes these share awards better align the interests of its employees with those of its shareholders. Stock compensation cost is recognized over the required service vesting period for the awards, based on the grant-date fair value, net of estimated forfeitures, and is included as a component of compensation and benefits reflected in non-interest expense. Stock compensation expense of $2.5 million and $2.7 million for the three months ended June 30, 2018 and 2017 , respectively, and $5.9 million and $6.0 million for the six months ended June 30, 2018 and 2017 , respectively, related to restricted stock awards, was recognized in the accompanying Condensed Consolidated Statements of Income. At June 30, 2018 there was $18.4 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 six months ended June 30, 2018 : Restricted Stock Awards Outstanding Stock Options Outstanding Time-Based Performance-Based Number of Shares Weighted-Average Grant Date Fair Value Number of Shares Weighted-Average Grant Date Fair Value Number of Shares Weighted-Average Exercise Price Outstanding, at January 1, 2018 207,800 $ 43.16 78,916 $ 45.35 673,039 $ 18.75 Granted 122,948 56.87 75,707 55.82 — — Vested restricted stock awards (1) 87,408 43.71 38,426 45.26 — — Forfeited 3,296 52.74 6,192 50.64 — — Exercised options — — — — 180,247 11.71 Outstanding and exercisable, at June 30, 2018 240,044 $ 49.85 110,005 $ 52.29 492,792 $ 21.33 (1) Vested for purposes of recording compensation expense. Time-based restricted stock. Time-based restricted stock awards vest over the applicable service period ranging from 1 to 3 years. The number of time-based awards that may be granted to an eligible individual in a calendar year is limited to 100,000 shares. Compensation expense is recorded over the vesting period based on 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 2018 is based upon Webster's ranking for total shareholder return versus Webster's compensation peer group companies and the remaining 50% is based upon Webster's average of return on equity during the 3 year vesting period. The compensation peer group companies are utilized because they represent the financial institutions that best compare with Webster. The Company records compensation expense over the vesting period, based on a fair value calculated using the Monte-Carlo simulation model, which allows for the incorporation of the performance condition for the 50% of the performance-based shares tied to total shareholder return versus the compensation peer group, and based on a fair value of the market price on the date of grant for the remaining 50% of the performance-based shares tied to Webster's return on equity. Compensation expense is subject to adjustment based on management's assessment of Webster's return on equity performance relative to the target number of shares condition. 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 458,904 non-qualified stock options and 33,888 incentive stock options outstanding at June 30, 2018

Segment Reporting

Segment Reporting	6 Months Ended
	Jun. 30, 2018
Segment Reporting [Abstract]
Segment Reporting	Segment Reporting Webster’s operations are organized into three reportable segments that represent its primary businesses - Commercial Banking, HSA Bank, and Community Banking. These three segments reflect how executive management responsibilities are assigned, the primary businesses, the products and services provided, the type of customer served, and how discrete financial information is currently evaluated. The Corporate Treasury unit of the Company, along with the amounts required to reconcile profitability metrics to amounts reported in accordance with GAAP, are included in the Corporate and Reconciling category. Description of Segment Reporting Methodology Webster’s reportable segment results are intended to reflect each segment as if it were a stand-alone business. Webster uses an internal profitability reporting system to generate information by operating segment, which is based on a series of management estimates and allocations regarding funds transfer pricing, provision for loan and lease losses, non-interest expense, income taxes, and equity capital. These estimates and allocations, certain of which are subjective in nature, are periodically reviewed and refined. Changes in estimates and allocations that affect the reported results of any operating segment do not affect the consolidated financial position or results of operations of Webster as a whole. The full profitability measurement reports, which are prepared for each operating segment, reflect non-GAAP reporting methodologies. The differences between full profitability and GAAP results are reconciled in the Corporate and Reconciling category. Webster allocates interest income and interest expense to each business, while also transferring the primary interest rate risk exposures to the Corporate and Reconciling category, using a matched maturity funding concept called Funds Transfer Pricing (FTP). The allocation process considers the specific interest rate risk and liquidity risk of financial instruments and other assets and liabilities in each line of business. The matched maturity funding concept considers the origination date and the earlier of the maturity date or the repricing date of a financial instrument to assign an FTP rate for loans and deposits originated each day. Loans are assigned an FTP rate for funds used and deposits are assigned an FTP rate for funds provided. This process is executed by the Company’s Financial Planning and Analysis division and is overseen by the Company's Asset/Liability Committee (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. The $7.2 million charge related to an accrual for additional FDIC premiums, for the three and six months ended June 30, 2018, is included in the Corporate and Reconciling category. See Note 1 to the Condensed Consolidated Financial Statements included in Item 1 of this report for additional information. Beginning in 2018, income tax expense is estimated for each reportable segment individually. The 2017 income tax expense was estimated for all segments using the consolidated effective tax rate. This change in the estimate of income tax expense reflects an estimate of full profitability for each of the individual business segments based on the nature of their operations. The following table presents total assets for Webster's reportable segments and the Corporate and Reconciling category: (In thousands) Commercial Banking HSA Bank Community Banking Corporate and Reconciling Consolidated Total At June 30, 2018 $ 9,972,737 $ 73,914 $ 8,793,382 $ 8,196,704 $ 27,036,737 At December 31, 2017 9,350,028 76,308 8,909,671 8,151,638 26,487,645 The following tables present the operating results, including all appropriate allocations, for Webster’s reportable segments and the Corporate and Reconciling category: Three months ended June 30, 2018 (In thousands) Commercial Banking HSA Bank Community Banking Corporate and Reconciling Consolidated Total Net interest income (expense) $ 88,459 $ 35,265 $ 101,902 $ (616 ) $ 225,010 Provision (benefit) for loan and lease losses 10,915 — (415 ) — 10,500 Net interest income (expense) after provision for loan and lease losses 77,544 35,265 102,317 (616 ) 214,510 Non-interest income 15,041 22,882 26,378 4,073 68,374 Non-interest expense 42,979 31,220 95,197 11,063 180,459 Income (loss) before income tax expense 49,606 26,927 33,498 (7,606 ) 102,425 Income tax expense (benefit) 12,203 7,001 6,666 (5,127 ) 20,743 Net income (loss) $ 37,403 $ 19,926 $ 26,832 $ (2,479 ) $ 81,682 Three months ended June 30, 2017 (In thousands) Commercial Banking HSA Community Banking Corporate and Reconciling Consolidated Total Net interest income (expense) $ 78,946 $ 25,574 $ 95,902 $ (2,635 ) $ 197,787 Provision (benefit) for loan and lease losses 10,692 — (3,442 ) — 7,250 Net interest income (expense) after provision for loan and lease losses 68,254 25,574 99,344 (2,635 ) 190,537 Non-interest income 12,532 19,750 28,058 4,211 64,551 Non-interest expense 37,304 28,750 94,322 4,043 164,419 Income (loss) before income tax expense 43,482 16,574 33,080 (2,467 ) 90,669 Income tax expense (benefit) 14,158 5,323 10,353 (744 ) 29,090 Net income (loss) $ 29,324 $ 11,251 $ 22,727 $ (1,723 ) $ 61,579 Six months ended June 30, 2018 (In thousands) Commercial Banking HSA Bank Community Banking Corporate and Reconciling Consolidated Total Net interest income (expense) $ 173,110 $ 68,189 $ 200,830 $ (2,951 ) $ 439,178 Provision for loan and lease losses 18,093 — 3,407 — 21,500 Net interest income (expense) after provision for loan and lease losses 155,017 68,189 197,423 (2,951 ) 417,678 Non-interest income 30,357 45,551 51,573 9,640 137,121 Non-interest expense 84,224 62,735 192,026 13,089 352,074 Income (loss) before income tax expense 101,150 51,005 56,970 (6,400 ) 202,725 Income tax expense (benefit) 24,883 13,261 11,337 (8,663 ) 40,818 Net income $ 76,267 $ 37,744 $ 45,633 $ 2,263 $ 161,907 Six months ended June 30, 2017 (In thousands) Commercial Banking HSA Bank Community Banking Corporate and Reconciling Consolidated Total Net interest income (expense) $ 157,193 $ 49,626 $ 189,492 $ (5,860 ) $ 390,451 Provision for loan and lease losses 17,489 — 261 — 17,750 Net interest income (expense) after provision for loan and lease losses 139,704 49,626 189,231 (5,860 ) 372,701 Non-interest income 25,956 39,021 53,437 9,179 127,593 Non-interest expense 75,428 56,989 189,501 6,285 328,203 Income (loss) before income tax expense 90,232 31,658 53,167 (2,966 ) 172,091 Income tax expense (benefit) 26,762 9,389 15,769 (879 ) 51,041 Net income (loss) $ 63,470 $ 22,269 $ 37,398 $ (2,087 ) $ 121,050

Revenue from Contracts with Cus

Revenue from Contracts with Customers Revenue from Contracts with customers	6 Months Ended
	Jun. 30, 2018
Revenue from Contract with Customer [Abstract]
Revenue from Contract with Customer [Text Block]	Revenue from Contracts with Customers The Company adopted ASU 2014-09, Revenue from Contracts with Customers (Topic 606), and the subsequent clarifying ASUs, effective January 1, 2018. The Updates are applicable to the Company's deposit service fees, wealth and investment services, and an insignificant component of other income included within non-interest income in the accompanying Condensed Consolidated Statements of Income. The Company's revenue associated with net interest income, and certain non-interest income line 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), are not within the scope of Topic 606. As a result, a substantial amount of the Company's revenue is not affected. Under the updated guidance, for in-scope revenue streams, the Company identifies the performance obligations included in the contracts with customers, determines the transaction price, allocates the transaction price to the performance, as applicable, and recognizes revenue when performance obligations are satisfied. The Company's existing recognition practices are largely consistent with the updated guidance. The following tables present the disaggregation by operating segment and major revenue stream, with disaggregated revenue reconciled to segment revenue as presented in Note 16: Segment Reporting : Three months ended June 30, 2018 (In thousands) Commercial HSA Community Corporate and Consolidated Major Revenue Streams Deposit service fees $ 3,180 $ 22,006 $ 15,663 $ 10 $ 40,859 Wealth and investment services 2,587 — 5,878 (9 ) 8,456 Other income — 876 640 — 1,516 Revenue from contracts with customers 5,767 22,882 22,181 1 50,831 Non-interest income within the scope of other GAAP topics 9,274 — 4,197 4,072 17,543 Total non-interest income $ 15,041 $ 22,882 $ 26,378 $ 4,073 $ 68,374 Three months ended June 30, 2017 (In thousands) Commercial HSA Community Corporate and Consolidated Major Revenue Streams Deposit service fees $ 3,015 $ 19,034 $ 16,081 $ 62 $ 38,192 Wealth and investment services 2,445 — 5,441 (9 ) 7,877 Other income — 716 163 — 879 Revenue from contracts with customers 5,460 19,750 21,685 53 46,948 Non-interest income within the scope of other GAAP topics 7,072 — 6,373 4,158 17,603 Total non-interest income $ 12,532 $ 19,750 $ 28,058 $ 4,211 $ 64,551 Six months ended June 30, 2018 (In thousands) Commercial HSA Community Corporate and Consolidated Major Revenue Streams Deposit service fees $ 6,402 $ 43,818 $ 30,972 $ 118 $ 81,310 Wealth and investment services 5,126 — 11,217 (17 ) 16,326 Other income — 1,733 1,133 — 2,866 Revenue from contracts with customers 11,528 45,551 43,322 101 100,502 Non-interest income within the scope of other GAAP topics 18,829 — 8,251 9,539 36,619 Total non-interest income $ 30,357 $ 45,551 $ 51,573 $ 9,640 $ 137,121 Six months ended June 30, 2017 (In thousands) Commercial HSA Community Corporate and Consolidated Major Revenue Streams Deposit service fees $ 5,893 $ 37,518 $ 31,611 $ 176 $ 75,198 Wealth and investment services 4,817 — 10,350 (17 ) 15,150 Other income — 1,503 387 — 1,890 Revenue from contracts with customers 10,710 39,021 42,348 159 92,238 Non-interest income within the scope of other GAAP topics 15,246 — 11,089 9,020 35,355 Total non-interest income $ 25,956 $ 39,021 $ 53,437 $ 9,179 $ 127,593 Deposit service fees Deposit service fees predominately consist of fees earned from deposit accounts and interchange revenue. Fees earned from deposit accounts relate to event-driven services and periodic account maintenance activities. Webster's obligations for event-driven services are satisfied at the time the service is delivered, while the obligations for maintenance services is satisfied monthly. Interchange fees are assessed as the performance obligation is satisfied, which is at the point in time the card transaction is authorized. Wealth and investment services

Commitments and Contingencies

Commitments and Contingencies	6 Months Ended
	Jun. 30, 2018
Commitments and Contingencies Disclosure [Abstract]
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 June 30, 2018 At December 31, 2017 Commitments to extend credit $ 5,929,945 $ 5,567,687 Standby letter of credit 206,506 195,902 Commercial letter of credit 44,176 43,200 Total credit-related financial instruments with off-balance sheet risk $ 6,180,627 $ 5,806,789 Commitments to Extend Credit . The Company makes commitments under various terms to lend funds to customers at a future point in time. These commitments include revolving credit arrangements, term loan commitments, and short-term borrowing agreements. Most of these loans have fixed expiration dates or other termination clauses where a fee may be required. Since commitments routinely expire without being funded, or after required availability of collateral occurs, the total commitment amount does not necessarily represent future liquidity requirements. Standby Letter of Credit . A standby letter of credit commits the Company to make payments on behalf of customers if certain specified future events occur. The Company has recourse against the customer for any amount required to be paid to a third party under a standby letter of credit, which is often part of a larger credit agreement under which security is provided. Historically, a large percentage of standby letters of credit expire without being funded. The contractual amount of a standby letter of credit represents the maximum amount of potential future payments the Company could be required to make, and is the Company's maximum credit risk. Commercial Letter of Credit . A commercial letter of credit is issued to facilitate either domestic or foreign trade arrangements for customers. As a general rule, drafts are committed to be drawn when the goods underlying the transaction are in transit. Similar to a standby letter of credit, a commercial letter of credit is often secured by an underlying security agreement including the assets or inventory 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 June 30, Six months ended June 30, (In thousands) 2018 2017 2018 2017 Beginning balance $ 2,294 $ 2,655 $ 2,362 $ 2,287 Provision (benefit) charged to expense 302 (111 ) 234 257 Ending balance $ 2,596 $ 2,544 $ 2,596 $ 2,544 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 June 30, 2018

Summary of Significant Accoun27

Summary of Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 30, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	Basis of Presentation The accounting and reporting policies of the Company that materially affect its financial statements conform with U.S. Generally Accepted Accounting Principles (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, 2017 , included in the Company's Annual Report on Form 10-K filed with the U.S. Securities and Exchange Commission (SEC) on March 1, 2018. Use of Estimates
New Accounting Pronouncements, Policy [Policy Text Block]	Accounting Standards Adopted During 2018 Effective January 1, 2018 , the following new Accounting Standards Updates (ASUs) were adopted by the Company: ASU No. 2017-08, Receivables - Nonrefundable Fees and Other Costs (Subtopic 310-20) - Premium Amortization on Purchased Callable Debt Securities. The Update shortens the amortization period for certain investments in callable debt securities purchased at a premium by requiring that the premium be amortized to the earliest call date. Prior to adoption, the Company amortized the premium as a yield adjustment over the contractual life of such debt securities. The Update accelerates the Company's recognition of premium amortization on certain debt securities held within the portfolio. The Company adopted the Update during the first quarter of 2018 on a modified retrospective basis. As a result, the Company recorded a $2.8 million cumulative-effect adjustment directly to retained earnings as of January 1, 2018. ASU No. 2017-07, Compensation - Retirement Benefits (Topic 715) - Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost. The Update requires the Company to retrospectively report service cost as a part of compensation expense and the other components of net periodic benefit cost separately from service cost in the Company's consolidated financial statements. The Company previously included all components of net periodic benefit cost as a component of compensation and benefits expense. Upon adoption, only service cost remains in compensation and benefits expense, while the interest cost on benefit obligations, expected return on plan assets, amortization of prior service cost, and recognized net loss components of the net periodic benefit cost are included in other expense, in the accompanying Condensed Consolidated Statements of Income. The Company adopted the Update during the first quarter of 2018 on a retrospective basis. As a result, the Company reclassified, for prior periods, the components of it's net periodic benefit costs other than the service cost component from compensation and benefits to other expense in the accompanying Condensed Consolidated Statements of Income. The adoption of this guidance did not have a material impact on the Company's consolidated financial statements. ASU No. 2016-15, Statement of Cash Flows (Topic 230) - Classification of Certain Cash Receipts and Cash Payments. The Update addresses the following eight specific cash flow issues, with the objective of reducing the existing diversity in practice: debt prepayment or debt extinguishment costs; settlement of zero-coupon debt instruments or other debt instruments with coupon interest rates that are insignificant in relation to the effective interest rate of the borrowing; contingent consideration payments made after a business combination; proceeds from the settlement of insurance claims; proceeds from the settlement of corporate-owned life insurance policies, including bank-owned life insurance policies; distributions received from equity method investees; beneficial interests in securitization transactions; and separately identifiable cash flows and application of the predominance principle. The Company adopted the Update during the first quarter of 2018 on a retrospective basis. The adoption of this guidance did not have a material impact on the Company's consolidated financial statements. ASU No. 2016-01, Financial Instruments - Overall (Subtopic 825-10) - Recognition and Measurement of Financial Assets and Financial Liabilities, and ASU No. 2018-03, Technical Corrections and Improvements to Financial Instruments - Overall (Subtopic 825-10) The Updates included targeted amendments in connection with the recognition, measurement, presentation, and disclosure of financial instruments. The main provisions require investments in equity securities to be measured at fair value through net income, unless they qualify for a practical expedient, and require fair value changes arising from changes in instrument-specific credit risk for financial liabilities that are measured under the fair value option to be recognized in other comprehensive income. The provisions also emphasized the existing requirement to use exit prices to measure fair value for disclosure purposes. The Company adopted the Updates during the first quarter of 2018 primarily on a modified retrospective basis. As a result, the Company recorded a benefit of $1.4 million for a cumulative-effect adjustment directly to retained earnings, as of January 1, 2018, due to a change in valuation method, from cost less impairment, to net asset value using the practical expedient. Also, the measurement alternative has been elected for equity securities, existing as of January 1, 2018, without readily determinable fair values on a prospective basis. ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606) and subsequent ASUs issued to clarify this Topic. The Update, and subsequent related updates, establish a single comprehensive model for entities to use in accounting for revenue arising from contracts with customers and supersedes most previous revenue recognition guidance, including industry-specific guidance. The Updates are intended to increase comparability across industries. The core principle of the revenue model is that a company will recognize revenue when it transfers control of goods or services to customers, at an amount that reflects the consideration to which it expects to be entitled in exchange for those goods or services. The Company adopted the Updates during the first quarter of 2018 on a modified retrospective transition approach. The Company did not identify any material changes to the timing of revenue recognition. The Company is changing how it presents certain recurring revenue streams associated with wealth and investment services as other income, versus a contra expense; however, these changes did not have a significant impact on the Company's consolidated financial statements. The adoption of this guidance did not have a material impact on the Company's financial condition or results of operations, and there was no cumulative effect adjustment to opening retained earnings as no material changes were identified in the timing of revenue recognition, however, additional disclosure has been incorporated in Note 17: Revenue from Contracts with Customers . Accounting Standards Issued But Not Yet Adopted The following list identifies ASUs applicable to the Company that have been issued by the FASB but are not yet effective: ASU No. 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 a Company will recognize a cumulative effect of the change on the opening balance for each affected component of equity in the financial statements as of the date of adoption. The Update is effective for the Company on January 1, 2019. The Company does not expect the new guidance to have a material impact on its financial statements. ASU No. 2017-04, Intangibles - Goodwill and Other (Topic 350) - Simplifying the Test for Goodwill Impairment. The Update simplifies quantitative goodwill impairment testing by requiring entities to compare the fair value of a reporting unit with its carrying amount and recognize an impairment charge for any amount by which the carrying amount exceeds the reporting unit's fair value, to the extent that the loss recognized does not exceed the amount of goodwill allocated to that reporting unit. This changes current guidance by eliminating the second step of the goodwill impairment analysis which involves calculating the implied fair value of goodwill determined in the same manner as the amount of goodwill recognized in a business combination upon acquisition. Entities will still have the option to perform the qualitative assessment for a reporting unit to determine if the quantitative impairment test is necessary. The Update is effective for the Company on January 1, 2020 and early adoption is permitted. The Update must be applied prospectively. The Company does not expect the new guidance to have a material impact on its 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. This approach 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 may result in a material increase to the Company's accounting for credit losses on financial instruments. To prepare for implementation of the new standard the Company has established a project lead and has empowered a cross functional steering committee comprised of members from different disciplines including Credit, Finance and Treasury as well as specific working groups to focus on key components of the development process. Through these working groups, the Company has begun to evaluate the effect that this Update will have on its financial statements and related disclosures. An implementation project plan has been created and is made up of targeted work streams focused on credit models, data management, treasury, and accounting. These work streams are collectively assessing resources that may be required, use of existing and new models, and data availability. The Company recently contracted with a system solution provider and is preparing to commence its implementation. The Update is effective for the Company on January 1, 2020. The impact of adopting the Update is expected to be influenced by assessment of the composition, characteristics, and credit quality of our loan and securities portfolios as well as the economic conditions in effect at the adoption date. Therefore, we are currently unable to reasonably estimate the impact of adopting the Update at this time. ASU No. 2016-02, Leases (Topic 842) and subsequent ASUs issued to amend this Topic. The Update introduces a lessee model that requires substantially all leases to be recorded as assets and liabilities on the balance sheet and will require both quantitative and qualitative disclosures regarding key information about leasing arrangements. In July 2018, the FASB issued a subsequent Update which, among other issues, incorporates a new transition method option that would allow the Company to use the effective date as the date of initial application on transition. The Company currently expects to elect this transition method. The Company is in the process of reviewing its existing leases, and certain service contracts for embedded leases, to evaluate the impact of these Updates on the consolidated financial statements, as well as the impact to regulatory reporting, such as capital and risk-weighted assets. The Company has engaged a third party consultant to assist with the implementation efforts and has selected a third party software solution to assist with the accounting under these Updates.

Investment Securities (Tables)

Investment Securities (Tables)	6 Months Ended
	Jun. 30, 2018
Investments, Debt and Equity Securities [Abstract]
Summary of Investment Securities	A summary of the amortized cost and fair value of investment securities is presented below: At June 30, 2018 At December 31, 2017 (In thousands) Amortized Cost Unrealized Gains Unrealized Losses Fair Value Amortized Cost Unrealized Gains Unrealized Losses Fair Value Available-for-sale: U.S. Treasury Bills $ 2,491 $ — $ — $ 2,491 $ 1,247 $ — $ — $ 1,247 Agency CMO 271,712 268 (6,727 ) 265,253 308,989 1,158 (3,814 ) 306,333 Agency MBS 1,356,988 1,053 (46,200 ) 1,311,841 1,124,960 2,151 (19,270 ) 1,107,841 Agency CMBS 618,054 — (35,378 ) 582,676 608,276 — (20,250 ) 588,026 CMBS 373,916 958 (318 ) 374,556 358,984 2,157 (74 ) 361,067 CLO 187,697 538 (169 ) 188,066 209,075 910 (134 ) 209,851 Single issuer-trust preferred — — — — 7,096 — (46 ) 7,050 Corporate debt 56,197 404 (903 ) 55,698 56,504 797 (679 ) 56,622 Available-for-sale $ 2,867,055 $ 3,221 $ (89,695 ) $ 2,780,581 $ 2,675,131 $ 7,173 $ (44,267 ) $ 2,638,037 Held-to-maturity: Agency CMO $ 231,943 $ 296 $ (7,891 ) $ 224,348 $ 260,114 $ 664 $ (4,824 ) $ 255,954 Agency MBS 2,520,455 10,139 (90,415 ) 2,440,179 2,569,735 16,989 (37,442 ) 2,549,282 Agency CMBS 677,397 — (24,594 ) 652,803 696,566 — (10,011 ) 686,555 Municipal bonds and notes 697,066 1,948 (16,851 ) 682,163 711,381 8,584 (6,558 ) 713,407 CMBS 229,265 551 (3,419 ) 226,397 249,273 2,175 (620 ) 250,828 Private Label MBS 93 — — 93 323 1 — 324 Held-to-maturity $ 4,356,219 $ 12,934 $ (143,170 ) $ 4,225,983 $ 4,487,392 $ 28,413 $ (59,455 ) $ 4,456,350
Summary of Changes in OTTI	The following table presents activity for OTTI: Three months ended June 30, Six months ended June 30, (In thousands) 2018 2017 2018 2017 Beginning balance $ 1,364 $ 3,231 $ 1,364 $ 3,243 Reduction for investment securities sold or called (261 ) (126 ) (261 ) (138 ) Additions for OTTI not previously recognized in earnings — 126 — 126 Ending balance $ 1,103 $ 3,231 $ 1,103 $ 3,231
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 June 30, 2018 Less Than Twelve Months Twelve Months or Longer Total (Dollars in thousands) Fair Value Unrealized Losses Fair Value Unrealized Losses # of Holdings Fair Value Unrealized Losses Available-for-sale: Agency CMO $ 110,795 $ (1,853 ) $ 112,410 $ (4,874 ) 36 $ 223,205 $ (6,727 ) Agency MBS 645,678 (16,586 ) 552,321 (29,614 ) 165 1,197,999 (46,200 ) Agency CMBS 71,430 (2,761 ) 511,246 (32,617 ) 37 582,676 (35,378 ) CMBS 145,960 (318 ) — — 22 145,960 (318 ) CLO 41,259 (41 ) 15,029 (128 ) 3 56,288 (169 ) Single issuer-trust preferred — — — — — — — Corporate debt 36,073 (278 ) 1,770 (625 ) 5 37,843 (903 ) Available-for-sale in an unrealized loss position $ 1,051,195 $ (21,837 ) $ 1,192,776 $ (67,858 ) 268 $ 2,243,971 $ (89,695 ) Held-to-maturity: Agency CMO $ 100,551 $ (2,735 ) $ 96,424 $ (5,156 ) 24 $ 196,975 $ (7,891 ) Agency MBS 1,085,492 (29,208 ) 1,111,469 (61,207 ) 262 2,196,961 (90,415 ) Agency CMBS 518,344 (18,421 ) 134,459 (6,173 ) 56 652,803 (24,594 ) Municipal bonds and notes 250,878 (5,417 ) 218,705 (11,434 ) 212 469,583 (16,851 ) CMBS 147,266 (3,149 ) 12,758 (270 ) 20 160,024 (3,419 ) Held-to-maturity in an unrealized loss position $ 2,102,531 $ (58,930 ) $ 1,573,815 $ (84,240 ) 574 $ 3,676,346 $ (143,170 ) At December 31, 2017 Less Than Twelve Months Twelve Months or Longer Total (Dollars in thousands) Fair Value Unrealized Losses Fair Value Unrealized Losses # of Holdings Fair Value Unrealized Losses Available-for-sale: Agency CMO $ 81,001 $ (449 ) $ 119,104 $ (3,365 ) 27 $ 200,105 $ (3,814 ) Agency MBS 416,995 (2,920 ) 606,021 (16,350 ) 135 1,023,016 (19,270 ) Agency CMBS 54,182 (851 ) 533,844 (19,399 ) 36 588,026 (20,250 ) CMBS 23,869 (74 ) — — 6 23,869 (74 ) CLO 56,335 (134 ) — — 3 56,335 (134 ) Single issuer-trust preferred 7,050 (46 ) — — 1 7,050 (46 ) Corporate debt 11,082 (395 ) 6,265 (284 ) 4 17,347 (679 ) Available-for-sale in an unrealized loss position $ 650,514 $ (4,869 ) $ 1,265,234 $ (39,398 ) 212 $ 1,915,748 $ (44,267 ) Held-to-maturity: Agency CMO $ 98,090 $ (1,082 ) $ 106,775 $ (3,742 ) 22 $ 204,865 $ (4,824 ) Agency MBS 762,107 (4,555 ) 1,197,839 (32,887 ) 205 1,959,946 (37,442 ) Agency CMBS 576,770 (7,599 ) 109,785 (2,412 ) 56 686,555 (10,011 ) Municipal bonds and notes 6,432 (38 ) 226,861 (6,520 ) 92 233,293 (6,558 ) CMBS 92,670 (413 ) 14,115 (207 ) 13 106,785 (620 ) Held-to-maturity in an unrealized loss position $ 1,536,069 $ (13,687 ) $ 1,655,375 $ (45,768 ) 388 $ 3,191,444 $ (59,455 )
Summary of Debt Securities by Contractual Maturity	The amortized cost and fair value of debt securities by contractual maturity are set forth below: At June 30, 2018 Available-for-Sale Held-to-Maturity (In thousands) Amortized Cost Fair Value Amortized Cost Fair Value Due in one year or less $ 23,192 $ 23,191 $ 17,891 $ 18,013 Due after one year through five years 34,000 34,083 3,628 3,656 Due after five through ten years 314,281 313,644 40,865 40,977 Due after ten years 2,495,582 2,409,663 4,293,835 4,163,337 Total debt securities $ 2,867,055 $ 2,780,581 $ 4,356,219 $ 4,225,983

Loans and Leases (Tables)

Loans and Leases (Tables)	6 Months Ended
	Jun. 30, 2018
Loans and Leases Receivable Disclosure [Abstract]
Schedule of Accounts, Notes, Loans and Financing Receivable	The following table summarizes loans and leases: (In thousands) At June 30, At December 31, 2017 Residential $ 4,455,580 $ 4,490,878 Consumer 2,485,695 2,590,225 Commercial 5,981,556 5,368,694 Commercial Real Estate 4,580,200 4,523,828 Equipment Financing 522,965 550,233 Loans and leases (1) (2) $ 18,025,996 $ 17,523,858 (1) Loans and leases include net deferred fees and net premiums/discounts of $16.4 million and $20.6 million at June 30, 2018 and December 31, 2017 , respectively. (2) At June 30, 2018 the Company had pledged $6.5 billion
Past Due Financing Receivables	The following tables summarize the aging of loans and leases: At June 30, 2018 (In thousands) 30-59 Days Past Due and Accruing 60-89 Days 90 or More Days Past Due and Accruing Non-accrual Total Past Due and Non-accrual Current Total Loans Residential $ 6,449 $ 4,449 $ — $ 50,780 $ 61,678 $ 4,393,902 $ 4,455,580 Consumer: Home equity 8,286 3,022 — 36,849 48,157 2,208,522 2,256,679 Other consumer 1,860 1,215 — 1,583 4,658 224,358 229,016 Commercial: Commercial non-mortgage 3,410 1,790 62 36,687 41,949 4,979,771 5,021,720 Asset-based — — — 1,160 1,160 958,676 959,836 Commercial real estate: Commercial real estate 720 — — 9,609 10,329 4,411,603 4,421,932 Commercial construction — — — — — 158,268 158,268 Equipment financing 1,991 331 — 3,510 5,832 517,133 522,965 Total $ 22,716 $ 10,807 $ 62 $ 140,178 $ 173,763 $ 17,852,233 $ 18,025,996 At December 31, 2017 (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 $ 8,643 $ 5,146 $ — $ 44,481 $ 58,270 $ 4,432,608 $ 4,490,878 Consumer: Home equity 12,668 5,770 — 35,645 54,083 2,298,185 2,352,268 Other consumer 2,556 1,444 — 1,707 5,707 232,250 237,957 Commercial: Commercial non-mortgage 5,212 603 644 39,214 45,673 4,488,242 4,533,915 Asset-based — — — 589 589 834,190 834,779 Commercial real estate: Commercial real estate 478 77 248 4,484 5,287 4,238,987 4,244,274 Commercial construction — — — — — 279,554 279,554 Equipment financing 1,732 626 — 393 2,751 547,482 550,233 Total $ 31,289 $ 13,666 $ 892 $ 126,513 $ 172,360 $ 17,351,498 $ 17,523,858
Activity In Allowance For Losses	The following tables summarize the activity in, as well as the loan and lease balances that were evaluated for, the allowance for loan and lease losses (ALLL): At or for the three months ended June 30, 2018 Residential Consumer Commercial Commercial Real Estate Equipment Financing Total ALLL: Balance, beginning of period $ 18,777 $ 34,239 $ 95,573 $ 51,436 $ 5,324 $ 205,349 Provision charged to expense 659 813 4,490 4,428 110 10,500 Charge-offs (754 ) (4,907 ) (5,632 ) (40 ) (65 ) (11,398 ) Recoveries 325 1,614 909 9 14 2,871 Balance, end of period $ 19,007 $ 31,759 $ 95,340 $ 55,833 $ 5,383 $ 207,322 At or for the three months ended June 30, 2017 (In thousands) Residential Consumer Commercial Commercial Real Estate Equipment Financing Total ALLL: Balance, beginning of period $ 20,264 $ 45,408 $ 76,354 $ 50,727 $ 6,354 $ 199,107 (Benefit) provision charged to expense (1,621 ) 1,562 5,489 1,771 49 7,250 Charge-offs (623 ) (5,602 ) (2,196 ) (100 ) (119 ) (8,640 ) Recoveries 407 1,120 317 4 13 1,861 Balance, end of period $ 18,427 $ 42,488 $ 79,964 $ 52,402 $ 6,297 $ 199,578 At or for the six months ended June 30, 2018 (In thousands) Residential Consumer Commercial Commercial Real Estate Equipment Financing Total ALLL: Balance, beginning of period $ 19,058 $ 36,190 $ 89,533 $ 49,407 $ 5,806 $ 199,994 Provision (benefit) charged to expense 909 2,493 11,910 6,532 (344 ) 21,500 Charge-offs (1,671 ) (9,981 ) (7,129 ) (117 ) (110 ) (19,008 ) Recoveries 711 3,057 1,026 11 31 4,836 Balance, end of period $ 19,007 $ 31,759 $ 95,340 $ 55,833 $ 5,383 $ 207,322 Individually evaluated for impairment $ 4,330 $ 1,498 $ 6,007 $ 2,061 $ 18 $ 13,914 Collectively evaluated for impairment $ 14,677 $ 30,261 $ 89,333 $ 53,772 $ 5,365 $ 193,408 Loan and lease balances: Individually evaluated for impairment $ 109,636 $ 41,636 $ 87,071 $ 12,677 $ 6,185 $ 257,205 Collectively evaluated for impairment 4,345,944 2,444,059 5,894,485 4,567,523 516,780 17,768,791 Loans and leases $ 4,455,580 $ 2,485,695 $ 5,981,556 $ 4,580,200 $ 522,965 $ 18,025,996 At or for the six months ended June 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 (4,088 ) 6,888 9,739 5,116 95 17,750 Charge-offs (1,355 ) (12,076 ) (2,319 ) (202 ) (304 ) (16,256 ) Recoveries 644 2,443 639 11 27 3,764 Balance, end of period $ 18,427 $ 42,488 $ 79,964 $ 52,402 $ 6,297 $ 199,578 Individually evaluated for impairment $ 5,105 $ 1,829 $ 10,951 $ 324 $ 27 $ 18,236 Collectively evaluated for impairment $ 13,322 $ 40,659 $ 69,013 $ 52,078 $ 6,270 $ 181,342 Loan and lease balances: Individually evaluated for impairment $ 117,820 $ 47,310 $ 83,206 $ 18,677 $ 6,332 $ 273,345 Collectively evaluated for impairment 4,270,488 2,552,008 5,060,965 4,537,531 579,341 17,000,333 Loans and leases $ 4,388,308 $ 2,599,318 $ 5,144,171 $ 4,556,208 $ 585,673 $ 17,273,678
Impaired Loans	The following tables summarize impaired loans and leases: At June 30, 2018 (In thousands) Unpaid Principal Balance Total Recorded Investment No Allowance Recorded Investment With Allowance Related Valuation Allowance Residential $ 120,019 $ 109,636 $ 68,854 $ 40,782 $ 4,330 Consumer - home equity 46,758 41,636 32,140 9,496 1,498 Commercial : Commercial non-mortgage 99,170 85,911 52,522 33,389 6,007 Asset-based 1,197 1,160 1,160 — — Commercial real estate: Commercial real estate 13,490 12,677 2,812 9,865 2,061 Commercial construction — — — — — Equipment financing 6,254 6,185 5,792 393 18 Total $ 286,888 $ 257,205 $ 163,280 $ 93,925 $ 13,914 At December 31, 2017 (In thousands) Unpaid Principal Balance Total Recorded Investment No Allowance Recorded Investment With Allowance Related Valuation Allowance Residential $ 125,352 $ 114,295 $ 69,759 $ 44,536 $ 4,805 Consumer - home equity 50,809 45,436 34,418 11,018 1,668 Commercial : Commercial non-mortgage 79,900 71,882 27,313 44,569 9,786 Asset-based 3,272 589 589 — — Commercial real estate: Commercial real estate 11,994 11,226 6,387 4,839 272 Commercial construction — — — — — Equipment financing 3,409 3,325 2,932 393 23 Total $ 274,736 $ 246,753 $ 141,398 $ 105,355 $ 16,554 The following table summarizes the average recorded investment and interest income recognized for impaired loans and leases: Three months ended June 30, Six months ended June 30, 2018 2017 2018 2017 (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 $ 110,787 $ 948 $ 265 $ 119,398 $ 1,036 $ 286 $ 111,965 $ 1,929 $ 518 $ 118,622 $ 2,106 $ 701 Consumer - home equity 42,112 290 250 47,296 335 249 43,536 584 500 46,514 657 562 Commercial: Commercial non-mortgage 80,475 871 — 85,006 233 — 78,896 1,410 — 68,122 455 — Asset based 1,347 — — — — — 875 — — — — — Commercial real estate: Commercial real estate 11,802 38 — 20,454 98 — 11,951 134 — 20,851 233 — Commercial construction — — — 862 — — — — — 865 12 — Equipment financing 6,320 35 — 6,240 67 — 4,755 71 — 6,376 138 — Total $ 252,843 $ 2,182 $ 515 $ 279,256 $ 1,769 $ 535 $ 251,978 $ 4,128 $ 1,018 $ 261,350 $ 3,601 $ 1,263
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 June 30, At December 31, At June 30, At December 31, At June 30, At December 31, (1) - (6) Pass $ 5,574,419 $ 5,048,162 $ 4,422,144 $ 4,355,916 $ 497,193 $ 525,105 (7) Special Mention 172,017 104,594 48,683 62,065 6,490 8,022 (8) Substandard 226,275 206,883 109,373 105,847 19,282 17,106 (9) Doubtful 8,845 9,055 — — — — Total $ 5,981,556 $ 5,368,694 $ 4,580,200 $ 4,523,828 $ 522,965 $ 550,233
Troubled Debt Restructurings on Financing Receivables	Troubled Debt Restructurings The following table summarizes information for troubled debt restructurings (TDRs): (Dollars in thousands) At June 30, At December 31, 2017 Accrual status $ 150,459 $ 147,113 Non-accrual status 79,515 74,291 Total recorded investment of TDRs $ 229,974 $ 221,404 Specific reserves for TDRs included in the balance of ALLL $ 11,334 $ 12,384 Additional funds committed to borrowers in TDR status 7,206 2,736 For the portion of TDRs deemed to be uncollectible, Webster charged off $4.5 million and $0.6 million for the three months ended June 30, 2018 and 2017 , respectively, and $5.2 million , and $2.6 million for the six months ended June 30, 2018 and 2017 , respectively. The following table provides information on the type of concession for loans and leases modified as TDRs: Three months ended June 30, Six months ended June 30, 2018 2017 2018 2017 Number of Post- (1) Number of Post- (1) Number of Post- (1) Number of Post- (1) (Dollars in thousands) Residential Extended Maturity — $ — 4 $ 420 — $ — 9 $ 1,390 Adjusted Interest Rate — — 2 335 — — 2 335 Maturity/Rate Combined 3 276 2 354 3 276 5 846 Other (2) 8 1,685 7 1,176 13 2,442 26 4,114 Consumer - home equity Extended Maturity — — 4 625 2 193 6 664 Adjusted Interest Rate — — — — — — — — Maturity/Rate Combined 1 335 4 830 3 448 11 2,813 Other (2) 14 915 10 701 25 1,693 43 2,894 Commercial non - mortgage Extended Maturity — — 6 778 3 85 8 813 Adjusted Interest Rate — — — — — — — — Maturity/Rate Combined 2 51 5 8,854 2 51 5 8,854 Other (2) 7 24,059 — — 9 28,743 1 4 Commercial real estate Extended Maturity 1 52 — — 2 97 — — Maturity/Rate Combined 1 245 — — 1 245 — — Other (2) 1 5,111 — — 1 5,111 — — Equipment Financing Extended Maturity — — — — — — — — Total TDRs 38 $ 32,729 44 $ 14,073 64 $ 39,384 116 $ 22,727 (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. There were no significant amounts of loans and leases modified as TDRs within the previous 12 months and for which there was a payment default during the three and six months ended June 30, 2018 or 2017 . The recorded investment of TDRs in commercial, commercial real estate, and equipment financing segregated by risk rating exposure is as follows: (In thousands) At June 30, 2018 At December 31, 2017 (1) - (6) Pass $ 3,886 $ 8,268 (7) Special Mention 14,109 355 (8) Substandard 60,706 53,050 (9) Doubtful — — Total $ 78,701 $ 61,673

Transfers of Financial Assets (

Transfers of Financial Assets (Tables)	6 Months Ended
	Jun. 30, 2018
Transfers and Servicing [Abstract]
Schedule Of Reserve For Loan Repurchases Table	The following table provides a summary of activity in the reserve for loan repurchases: Three months ended June 30, Six months ended June 30, (In thousands) 2018 2017 2018 2017 Beginning balance $ 664 $ 824 $ 872 $ 790 Provision (benefit) charged to expense 13 19 (190 ) 53 Repurchased loans and settlements charged off (3 ) — (8 ) — Ending balance $ 674 $ 843 $ 674 $ 843 Three months ended June 30, Six months ended June 30, (In thousands) 2018 2017 2018 2017 Beginning balance $ 2,294 $ 2,655 $ 2,362 $ 2,287 Provision (benefit) charged to expense 302 (111 ) 234 257 Ending balance $ 2,596 $ 2,544 $ 2,596 $ 2,544
Transfer of Financial Assets Accounted for as Sales [Table Text Block]	The following table provides information for mortgage banking activities: Three months ended June 30, Six months ended June 30, (In thousands) 2018 2017 2018 2017 Residential mortgage loans held for sale: Proceeds from sale $ 45,257 $ 66,718 $ 90,063 $ 173,338 Loans sold with servicing rights retained 39,822 60,167 79,726 159,667 Net gain on sale 598 2,126 1,681 2,377 Ancillary fees 402 641 812 1,409 Fair value option adjustment 235 584 (114 ) 1,831
Servicing Asset at Amortized Cost [Table Text Block]	The following table presents the changes in carrying value for mortgage servicing assets: Three months ended June 30, Six months ended June 30, (In thousands) 2018 2017 2018 2017 Beginning balance $ 24,403 $ 24,336 $ 25,139 $ 24,466 Additions 1,038 2,478 2,450 4,487 Amortization (2,100 ) (2,106 ) (4,248 ) (4,245 ) Ending balance $ 23,341 $ 24,708 $ 23,341 $ 24,708

Goodwill and Other Intangible31

Goodwill and Other Intangible Assets (Tables)	6 Months Ended
	Jun. 30, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Finite-Lived Intangible Assets	Goodwill and other intangible assets by reportable segment consisted of the following: At June 30, 2018 At December 31, 2017 (In thousands) Gross Carrying Amount Accumulated Amortization Net Carrying Amount Gross Carrying Amount Accumulated Amortization Net Carrying Amount Goodwill: Community Banking $ 516,560 $ 516,560 HSA Bank 21,813 21,813 Total goodwill $ 538,373 $ 538,373 Other intangible assets: HSA Bank - Core deposits $ 22,000 $ (9,725 ) $ 12,275 $ 22,000 $ (8,610 ) $ 13,390 HSA Bank - Customer relationships 21,000 (5,587 ) 15,413 21,000 (4,779 ) 16,221 Total other intangible assets $ 43,000 $ (15,312 ) $ 27,688 $ 43,000 $ (13,389 ) $ 29,611
Schedule Of Expected Amortization Expense, Next Four Years	As of June 30, 2018 , the remaining estimated aggregate future amortization expense for intangible assets is as follows: (In thousands) Remainder of 2018 $ 1,924 2019 3,847 2020 3,847 2021 3,847 2022 3,847 Thereafter 10,376

Deposits (Tables)

Deposits (Tables)	6 Months Ended
	Jun. 30, 2018
Banking and Thrift [Abstract]
Deposit Liabilities, Type [Table Text Block]	A summary of deposits by type follows: (In thousands) At June 30, At December 31, Non-interest-bearing: Demand $ 4,151,259 $ 4,191,496 Interest-bearing: Health savings accounts 5,517,929 5,038,681 Checking 2,637,346 2,736,952 Money market 2,016,453 2,209,492 Savings 4,180,666 4,348,700 Time deposits 2,839,703 2,468,408 Total interest-bearing 17,192,097 16,802,233 Total deposits $ 21,343,356 $ 20,993,729 Time deposits and interest-bearing checking, included in above balances, obtained through brokers $ 936,830 $ 898,157 Time deposits, included in above balance, that meet or exceed the FDIC limit 888,419 561,512 Deposit overdrafts reclassified as loan balances 3,587 2,210
Time Deposit Maturities [Table Text Block]	The scheduled maturities of time deposits are as follows: (In thousands) At June 30, Remainder of 2018 $ 1,016,354 2019 1,313,184 2020 314,856 2021 122,427 2022 47,641 Thereafter 25,241 Total time deposits $ 2,839,703

Borrowings (Tables)

Borrowings (Tables)	6 Months Ended
	Jun. 30, 2018
Debt Disclosure [Abstract]
Schedule of Repurchase Agreements	The following table summarizes securities sold under agreements to repurchase and other borrowings: At June 30, At December 31, (In thousands) Amount Rate Amount Rate Securities sold under agreements to repurchase (1) : Original maturity of one year or less $ 257,568 0.25 % $ 288,269 0.17 % Original maturity of greater than one year, non-callable 300,000 3.10 300,000 3.10 Total securities sold under agreements to repurchase 557,568 1.78 588,269 1.66 Fed funds purchased 305,000 1.99 55,000 1.37 Securities sold under agreements to repurchase and other borrowings $ 862,568 1.86 $ 643,269 1.64
Federal Home Loan Bank, Advances	The following table provides information for FHLB advances: At June 30, At December 31, (Dollars in thousands) Amount Weighted- Average Contractual Coupon Rate Amount Weighted- Average Contractual Coupon Rate Maturing within 1 year $ 1,075,000 1.99 % $ 1,150,000 1.48 % After 1 but within 2 years 153,026 1.78 103,026 1.81 After 2 but within 3 years 190,000 1.71 215,000 1.73 After 3 but within 4 years 150,000 3.24 200,000 2.06 (1) After 4 but within 5 years 160 — 170 — After 5 years 8,770 2.65 8,909 2.65 (1) FHLB advances and overall rate $ 1,576,956 2.06 $ 1,677,105 1.61 (1) Aggregate carrying value of assets pledged as collateral $ 6,216,042 $ 6,402,066 Remaining borrowing capacity 2,610,327 2,600,624 (1) Weighted-average contractual coupon rates for December 31, 2017 are presented as revised for these classifications to correct an immaterial error in presentation. The percentages reported in the Company's 2017 Annual Report on Form 10-K were: After 3 but within 4 years - 4.13% ; After 5 years - 1.96% ; and overall rate - 1.85%
Schedule of Long-term Debt Instruments	The following table summarizes long-term debt: (Dollars in thousands) At June 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 (667 ) (727 ) Debt issuance cost on senior fixed-rate notes (759 ) (826 ) Long-term debt $ 225,894 $ 225,767 (1) The interest rate on Webster Statutory Trust I floating-rate notes, which varies quarterly based on 3-month London Interbank Offered Rate plus 2.95% , was 5.28% at June 30, 2018 and 4.55% at December 31, 2017

Accumulated Other Comprehensi34

Accumulated Other Comprehensive Loss, Net of Tax (Tables)	6 Months Ended
	Jun. 30, 2018
Equity [Abstract]
Schedule of Changes in Accumulated Other Comprehensive Loss by Component	The following tables summarize the changes in accumulated other comprehensive loss, net of tax (AOCL) by component: Three months ended June 30, 2018 Six months ended June 30, 2018 (In thousands) Securities Available For Sale Derivative Instruments Defined Benefit Pension and Other Postretirement Benefit Plans Total Securities Available For Sale Derivative Instruments Defined Benefit Pension and Other Postretirement Benefit Plans Total Beginning balance $ (55,371 ) $ (12,494 ) $ (47,614 ) $ (115,479 ) $ (27,947 ) $ (15,016 ) $ (48,568 ) $ (91,531 ) (OCL) OCI before reclassifications (9,246 ) 294 — (8,952 ) (36,670 ) 1,423 — (35,247 ) Amounts reclassified from AOCL — 1,386 1,109 2,495 — 2,779 2,063 4,842 Net current-period OCI/(OCL) (9,246 ) 1,680 1,109 (6,457 ) (36,670 ) 4,202 2,063 (30,405 ) Ending balance $ (64,617 ) $ (10,814 ) $ (46,505 ) $ (121,936 ) $ (64,617 ) $ (10,814 ) $ (46,505 ) $ (121,936 ) Three months ended June 30, 2017 Six months ended June 30, 2017 (In thousands) Securities Available For Sale Derivative Instruments Defined Benefit Pension and Other Postretirement Benefit Plans Total Securities Available For Sale Derivative Instruments Defined Benefit Pension and Other Postretirement Benefit Plans Total Beginning balance $ (17,701 ) $ (15,909 ) $ (43,417 ) $ (77,027 ) $ (15,476 ) $ (17,068 ) $ (44,449 ) $ (76,993 ) OCI/(OCL) before reclassifications 3,200 (472 ) — 2,728 975 (411 ) — 564 Amounts reclassified from AOCL — 1,123 1,094 2,217 — 2,221 2,126 4,347 Net current-period OCI 3,200 651 1,094 4,945 975 1,810 2,126 4,911 Ending balance $ (14,501 ) $ (15,258 ) $ (42,323 ) $ (72,082 ) $ (14,501 ) $ (15,258 ) $ (42,323 ) $ (72,082 )
Schedule of Accumulated Other Comprehensive Loss	The following tables provide information for the items reclassified from AOCL: (In thousands) Three months ended June 30, Six months ended June 30, Associated Line Item in the Condensed Consolidated Statements of Income AOCL Components 2018 2017 2018 2017 Derivative instruments: Cash flow hedges $ (1,861 ) $ (1,771 ) $ (3,732 ) $ (3,506 ) Total interest expense Tax benefit 475 648 953 1,285 Income tax expense Net of tax $ (1,386 ) $ (1,123 ) $ (2,779 ) $ (2,221 ) Defined benefit pension and other postretirement benefit plans: Amortization of net loss $ (1,493 ) $ (1,734 ) $ (2,778 ) $ (3,372 ) (1) Tax benefit 384 640 715 1,246 Income tax expense Net of tax $ (1,109 ) $ (1,094 ) $ (2,063 ) $ (2,126 )

Regulatory Matters (Tables)

Regulatory Matters (Tables)	6 Months Ended
	Jun. 30, 2018
Regulatory Capital Requirements [Abstract]
Information On The Capital Ratios	The following table provides information on the capital ratios for Webster Financial Corporation and Webster Bank: At June 30, 2018 Actual Minimum Requirement Well Capitalized (Dollars in thousands) Amount Ratio Amount Ratio Amount Ratio Webster Financial Corporation CET1 risk-based capital $ 2,148,786 10.99 % $ 879,461 4.5 % $ 1,270,333 6.5 % Total risk-based capital 2,581,061 13.21 1,563,486 8.0 1,954,358 10.0 Tier 1 risk-based capital 2,293,823 11.74 1,172,615 6.0 1,563,486 8.0 Tier 1 leverage capital 2,293,823 8.70 1,054,648 4.0 1,318,310 5.0 Webster Bank CET1 risk-based capital $ 2,100,537 10.76 % $ 878,786 4.5 % $ 1,269,357 6.5 % Total risk-based capital 2,310,455 11.83 1,562,285 8.0 1,952,857 10.0 Tier 1 risk-based capital 2,100,537 10.76 1,171,714 6.0 1,562,285 8.0 Tier 1 leverage capital 2,100,537 7.97 1,054,035 4.0 1,317,543 5.0 At December 31, 2017 Actual Minimum Requirement Well Capitalized (Dollars in thousands) Amount Ratio Amount Ratio Amount Ratio Webster Financial Corporation CET1 risk-based capital $ 2,093,116 11.14 % $ 845,389 4.5 % $ 1,221,118 6.5 % Total risk-based capital 2,517,848 13.40 1,502,914 8.0 1,878,643 10.0 Tier 1 risk-based capital 2,238,172 11.91 1,127,186 6.0 1,502,914 8.0 Tier 1 leverage capital 2,238,172 8.63 1,036,817 4.0 1,296,021 5.0 Webster Bank CET1 risk-based capital $ 2,114,224 11.26 % $ 844,693 4.5 % $ 1,220,113 6.5 % Total risk-based capital 2,316,580 12.34 1,501,677 8.0 1,877,097 10.0 Tier 1 risk-based capital 2,114,224 11.26 1,126,258 6.0 1,501,677 8.0 Tier 1 leverage capital 2,114,224 8.14 1,038,442 4.0 1,298,052 5.0

Earnings Per Common Share (Tabl

Earnings Per Common Share (Tables)	6 Months Ended
	Jun. 30, 2018
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 June 30, Six Months Ended June 30, (In thousands, except per share data) 2018 2017 2018 2017 Earnings for basic and diluted earnings per common share: Net income $ 81,682 $ 61,579 $ 161,907 $ 121,050 Less: Preferred stock dividends 1,969 2,024 3,916 4,048 Net income available to common shareholders 79,713 59,555 157,991 117,002 Less: Earnings applicable to participating securities 224 70 418 176 Earnings applicable to common shareholders $ 79,489 $ 59,485 $ 157,573 $ 116,826 Shares: Weighted-average common shares outstanding - basic 91,893 92,092 91,913 91,989 Effect of dilutive securities: Stock options and restricted stock 274 397 317 475 Warrants 6 6 6 6 Weighted-average common shares outstanding - diluted 92,173 92,495 92,236 92,470 Earnings per common share: Basic $ 0.87 $ 0.65 $ 1.71 $ 1.27 Diluted 0.86 0.64 1.71 1.26
Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share	Potential common shares from non-participating restricted stock, of $53 thousand and $79 thousand for the three months ended June 30, 2018 and 2017 , respectively, and $61 thousand and $60 thousand for the six months ended June 30, 2018 and 2017 , respectively, are excluded from the effect of dilutive securities because, due to performance conditions, they would have been anti-dilutive.

Derivative Financial Instrume37

Derivative Financial Instruments (Tables)	6 Months Ended
	Jun. 30, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Fair Value Of Derivative Financial Instruments Designated As Cash Flow Hedges	The following table presents the notional amounts and fair value of derivative positions: At June 30, 2018 At December 31, 2017 Asset Derivatives Liability Derivatives Asset Derivatives Liability Derivatives (In thousands) Notional Fair Notional Fair Notional Fair Notional Fair Designated as cash flow hedging instruments: Positions subject to a master netting agreement (1) Interest rate derivatives (2) $ 325,000 $ 4,685 $ — $ — $ 325,000 $ 2,770 $ — $ — Not designated as hedging instruments: Positions subject to a master netting agreement (1) Interest rate derivatives (2) 3,523,220 12,286 198,836 321 2,791,760 5,977 721,048 1,968 Mortgage banking derivatives (3) 41,718 441 32,053 199 28,497 421 39,230 110 Other 29,571 629 38,224 485 7,914 258 30,328 419 Positions not subject to a master netting agreement (4) Interest rate derivatives 666,149 6,987 3,055,950 71,057 1,366,299 23,009 2,146,518 25,631 RPAs 85,164 26 95,340 58 93,713 80 116,882 111 Other 8,615 240 422 17 — — 2,073 184 Total not designated as hedging instruments 4,354,437 20,609 3,420,825 72,137 4,288,183 29,745 3,056,079 28,423 Gross derivative instruments, before netting $ 4,679,437 25,294 $ 3,420,825 72,137 $ 4,613,183 32,515 $ 3,056,079 28,423 Less: Legally enforceable master netting agreements 729 729 2,245 2,245 Less: Cash collateral posted 16,791 — 6,704 — Total derivative instruments, after netting $ 7,774 $ 71,408 $ 23,566 $ 26,178 (1) The Company has elected to report derivative positions subject to a legally enforceable master netting agreement on a net basis, net of cash collateral. Refer to the Offsetting Derivatives section of this footnote for additional information. (2) Balances related to CME are presented as a single unit of account. Notional amounts of interest rate swaps cleared through CME include; $2.5 billion and $1.9 billion for asset derivatives and $171 million and $595 million for liability derivatives at June 30, 2018 and December 31, 2017, respectively, with related fair values of approximately zero . (3) Notional amounts include mandatory forward commitments of $41.0 million , while notional amounts do not include approved floating rate commitments of $14.9 million , at June 30, 2018
Other Derivatives Not Designated For Hedge Accounting	Three months ended June 30, Six months ended June 30, (In thousands) 2018 2017 2018 2017 Designated as cash flow hedging instruments: Interest rate derivatives (1) $ 1,668 $ 1,986 $ 3,491 $ 4,025 Not designated as hedging instruments: Interest rate derivatives (2) $ 1,958 $ 1,361 $ 5,749 $ 2,895 RPAs 85 53 95 106 Mortgage banking derivatives (134 ) 374 (69 ) (1,667 ) Other (2) 1,939 (545 ) 1,339 (992 ) Total not designated as hedging instruments (2) (3) $ 3,848 $ 1,243 $ 7,114 $ 342
Offsetting Liabilities	The following table presents the transition from a gross basis to net basis, due to the application of counterparty netting agreements: At June 30, 2018 At December 31, 2017 (In thousands) Gross Amount Relationship Offset Cash Collateral Offset Net Amount Gross Amount Relationship Offset Cash Collateral Offset Net Amount Derivative instrument gains: Hedge accounting $ 4,685 $ — $ 4,685 $ — $ 2,770 $ 91 $ 2,679 $ — Non-hedge accounting 12,915 729 12,106 80 6,222 2,154 4,025 43 Total assets $ 17,600 $ 729 $ 16,791 $ 80 $ 8,992 $ 2,245 $ 6,704 $ 43 Derivative instrument losses: Hedge accounting $ — $ — $ — $ — $ — $ — $ — $ — Non-hedge accounting 806 729 — 77 2,387 2,245 — 142 Total liabilities $ 806 $ 729 $ — $ 77 $ 2,387 $ 2,245 $ — $ 142

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	6 Months Ended
	Jun. 30, 2018
Fair Value Disclosures [Abstract]
Fair Value Option, Disclosures	The following table presents the fair value, unpaid principal balance, and accrual status, of assets accounted for under the fair value option: At June 30, 2018 At December 31, 2017 (In thousands) Fair Value Unpaid Principal Balance Difference Fair Value Unpaid Principal Balance Difference Originated loans held for sale $ 18,645 $ 18,234 $ 411 $ 20,888 $ 20,346 $ 542 Electing to measure originated loans held for sale at fair value reduces certain timing differences and better matches changes in the value of these assets with changes in the value of the derivatives used as an economic hedge on these assets.
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 June 30, 2018 (In thousands) Level 1 Level 2 Level 3 NAV Total Financial assets held at fair value: U.S. Treasury Bills $ 2,491 $ — $ — $ — $ 2,491 Agency CMO — 265,253 — — 265,253 Agency MBS — 1,311,841 — — 1,311,841 Agency CMBS — 582,676 — — 582,676 CMBS — 374,556 — — 374,556 CLO — 188,066 — — 188,066 Single issuer-trust preferred — — — — — Corporate debt — 55,698 — — 55,698 Total available-for-sale investment securities 2,491 2,778,090 — — 2,780,581 Gross derivative instruments, before netting (1) 869 24,425 — — 25,294 Originated loans held for sale — 18,645 — — 18,645 Investments held in Rabbi Trust 4,726 — — — 4,726 Alternative investments 2,439 — — 1,895 4,334 Total financial assets held at fair value $ 10,525 $ 2,821,160 $ — $ 1,895 $ 2,833,580 Financial liabilities held at fair value: Gross derivative instruments, before netting (1) $ 485 $ 71,652 $ — $ — $ 72,137 At December 31, 2017 (In thousands) Level 1 Level 2 Level 3 NAV Total Financial assets held at fair value: U.S. Treasury Bills $ 1,247 $ — $ — $ — $ 1,247 Agency CMO — 306,333 — — 306,333 Agency MBS — 1,107,841 — — 1,107,841 Agency CMBS — 588,026 — — 588,026 CMBS — 361,067 — — 361,067 CLO — 209,851 — — 209,851 Single issuer-trust preferred — 7,050 — — 7,050 Corporate debt — 56,622 — — 56,622 Total available-for-sale investment securities 1,247 2,636,790 — — 2,638,037 Gross derivative instruments, before netting (1) 258 32,257 — — 32,515 Originated loans held for sale — 20,888 — — 20,888 Investments held in Rabbi Trust 4,801 — — — 4,801 Alternative investments — — — 3,495 3,495 Total financial assets held at fair value $ 6,306 $ 2,689,935 $ — $ 3,495 $ 2,699,736 Financial liabilities held at fair value: Gross derivative instruments, before netting (1) $ 587 $ 27,836 $ — $ — $ 28,423 (1) For information relating to the impact of netting derivative assets and derivative liabilities as well as the impact from offsetting cash collateral paid to the same derivative counterparties see Note 12: Derivative Financial Instruments
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 June 30, 2018 : (Dollars in thousands) Asset Fair Value Valuation Methodology Unobservable Inputs Range of Inputs Collateral dependent impaired loans and leases $ 15,414 Real Estate Appraisals Discount for appraisal type 0% - 15% Discount for costs to sell 0% - 8% OREO $ 467 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 June 30, 2018 At December 31, 2017 (In thousands) Carrying Amount Fair Value Carrying Amount Fair Value Assets: Level 2 Held-to-maturity investment securities $ 4,356,219 $ 4,225,983 $ 4,487,392 $ 4,456,350 Level 3 Loans and leases, net 17,818,674 17,642,617 17,323,864 17,211,619 Mortgage servicing assets 23,341 49,182 25,139 45,309 Liabilities: Level 2 Deposit liabilities $ 18,503,653 $ 18,503,653 $ 18,525,321 $ 18,525,321 Time deposits 2,839,703 2,811,645 2,468,408 2,455,245 Securities sold under agreements to repurchase and other borrowings 862,568 862,371 643,269 644,084 FHLB advances 1,576,956 1,576,797 1,677,105 1,678,070 Long-term debt (1) 225,894 230,223 225,767 234,359 (1) Adjustments to the carrying amount of long-term debt for unamortized discount and debt issuance cost on senior fixed-rate notes are not included for determination of fair value, see Note 8: Borrowings

Retirement Benefit Plans (Table

Retirement Benefit Plans (Tables)	6 Months Ended
	Jun. 30, 2018
Retirement Benefits [Abstract]
Summary of Net Periodic Benefit Cost	The following table summarizes the components of net periodic benefit cost: Three months ended June 30, 2018 2017 (In thousands) Pension Plan SERP Other Benefits Pension Plan SERP Other Benefits Service cost $ — $ — $ — $ 13 $ — $ — Interest cost on benefit obligations 1,935 (21 ) 19 1,844 93 25 Expected return on plan assets (3,180 ) — — (3,075 ) — — Amortization of prior service cost — — — — — — Recognized net loss 1,160 333 — 1,515 212 7 Net periodic benefit cost $ (85 ) $ 312 $ 19 $ 297 $ 305 $ 32 Six months ended June 30, 2018 2017 (In thousands) Pension Plan SERP Other Benefits Pension Plan SERP Other Benefits Service cost $ — $ — $ — $ 25 $ — $ — Interest cost on benefit obligations 3,720 166 39 3,657 185 50 Expected return on plan assets (6,360 ) — — (6,148 ) — — Amortization of prior service cost — — — — — — Recognized net loss 2,320 458 — 2,932 425 15 Net periodic benefit cost $ (320 ) $ 624 $ 39 $ 466 $ 610 $ 65

Share-Based Plans (Tables)

Share-Based Plans (Tables)	6 Months Ended
	Jun. 30, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Schedule of Share-based Compensation, Activity	The following table provides a summary of the stock compensation plans activity for the six months ended June 30, 2018 : Restricted Stock Awards Outstanding Stock Options Outstanding Time-Based Performance-Based Number of Shares Weighted-Average Grant Date Fair Value Number of Shares Weighted-Average Grant Date Fair Value Number of Shares Weighted-Average Exercise Price Outstanding, at January 1, 2018 207,800 $ 43.16 78,916 $ 45.35 673,039 $ 18.75 Granted 122,948 56.87 75,707 55.82 — — Vested restricted stock awards (1) 87,408 43.71 38,426 45.26 — — Forfeited 3,296 52.74 6,192 50.64 — — Exercised options — — — — 180,247 11.71 Outstanding and exercisable, at June 30, 2018 240,044 $ 49.85 110,005 $ 52.29 492,792 $ 21.33 (1)

Segment Reporting (Tables)

Segment Reporting (Tables)	6 Months Ended
	Jun. 30, 2018
Segment Reporting [Abstract]
Operating Results And Total Assets Reportable Segments	The following table presents total assets for Webster's reportable segments and the Corporate and Reconciling category: (In thousands) Commercial Banking HSA Bank Community Banking Corporate and Reconciling Consolidated Total At June 30, 2018 $ 9,972,737 $ 73,914 $ 8,793,382 $ 8,196,704 $ 27,036,737 At December 31, 2017 9,350,028 76,308 8,909,671 8,151,638 26,487,645 The following tables present the operating results, including all appropriate allocations, for Webster’s reportable segments and the Corporate and Reconciling category: Three months ended June 30, 2018 (In thousands) Commercial Banking HSA Bank Community Banking Corporate and Reconciling Consolidated Total Net interest income (expense) $ 88,459 $ 35,265 $ 101,902 $ (616 ) $ 225,010 Provision (benefit) for loan and lease losses 10,915 — (415 ) — 10,500 Net interest income (expense) after provision for loan and lease losses 77,544 35,265 102,317 (616 ) 214,510 Non-interest income 15,041 22,882 26,378 4,073 68,374 Non-interest expense 42,979 31,220 95,197 11,063 180,459 Income (loss) before income tax expense 49,606 26,927 33,498 (7,606 ) 102,425 Income tax expense (benefit) 12,203 7,001 6,666 (5,127 ) 20,743 Net income (loss) $ 37,403 $ 19,926 $ 26,832 $ (2,479 ) $ 81,682 Three months ended June 30, 2017 (In thousands) Commercial Banking HSA Community Banking Corporate and Reconciling Consolidated Total Net interest income (expense) $ 78,946 $ 25,574 $ 95,902 $ (2,635 ) $ 197,787 Provision (benefit) for loan and lease losses 10,692 — (3,442 ) — 7,250 Net interest income (expense) after provision for loan and lease losses 68,254 25,574 99,344 (2,635 ) 190,537 Non-interest income 12,532 19,750 28,058 4,211 64,551 Non-interest expense 37,304 28,750 94,322 4,043 164,419 Income (loss) before income tax expense 43,482 16,574 33,080 (2,467 ) 90,669 Income tax expense (benefit) 14,158 5,323 10,353 (744 ) 29,090 Net income (loss) $ 29,324 $ 11,251 $ 22,727 $ (1,723 ) $ 61,579 Six months ended June 30, 2018 (In thousands) Commercial Banking HSA Bank Community Banking Corporate and Reconciling Consolidated Total Net interest income (expense) $ 173,110 $ 68,189 $ 200,830 $ (2,951 ) $ 439,178 Provision for loan and lease losses 18,093 — 3,407 — 21,500 Net interest income (expense) after provision for loan and lease losses 155,017 68,189 197,423 (2,951 ) 417,678 Non-interest income 30,357 45,551 51,573 9,640 137,121 Non-interest expense 84,224 62,735 192,026 13,089 352,074 Income (loss) before income tax expense 101,150 51,005 56,970 (6,400 ) 202,725 Income tax expense (benefit) 24,883 13,261 11,337 (8,663 ) 40,818 Net income $ 76,267 $ 37,744 $ 45,633 $ 2,263 $ 161,907 Six months ended June 30, 2017 (In thousands) Commercial Banking HSA Bank Community Banking Corporate and Reconciling Consolidated Total Net interest income (expense) $ 157,193 $ 49,626 $ 189,492 $ (5,860 ) $ 390,451 Provision for loan and lease losses 17,489 — 261 — 17,750 Net interest income (expense) after provision for loan and lease losses 139,704 49,626 189,231 (5,860 ) 372,701 Non-interest income 25,956 39,021 53,437 9,179 127,593 Non-interest expense 75,428 56,989 189,501 6,285 328,203 Income (loss) before income tax expense 90,232 31,658 53,167 (2,966 ) 172,091 Income tax expense (benefit) 26,762 9,389 15,769 (879 ) 51,041 Net income (loss) $ 63,470 $ 22,269 $ 37,398 $ (2,087 ) $ 121,050

Revenue from Contracts with C42

Revenue from Contracts with Customers Disaggregation of Revenue (Tables)	6 Months Ended
	Jun. 30, 2018
Revenue from Contract with Customer [Abstract]
Disaggregation of Revenue [Table Text Block]	The following tables present the disaggregation by operating segment and major revenue stream, with disaggregated revenue reconciled to segment revenue as presented in Note 16: Segment Reporting : Three months ended June 30, 2018 (In thousands) Commercial HSA Community Corporate and Consolidated Major Revenue Streams Deposit service fees $ 3,180 $ 22,006 $ 15,663 $ 10 $ 40,859 Wealth and investment services 2,587 — 5,878 (9 ) 8,456 Other income — 876 640 — 1,516 Revenue from contracts with customers 5,767 22,882 22,181 1 50,831 Non-interest income within the scope of other GAAP topics 9,274 — 4,197 4,072 17,543 Total non-interest income $ 15,041 $ 22,882 $ 26,378 $ 4,073 $ 68,374 Three months ended June 30, 2017 (In thousands) Commercial HSA Community Corporate and Consolidated Major Revenue Streams Deposit service fees $ 3,015 $ 19,034 $ 16,081 $ 62 $ 38,192 Wealth and investment services 2,445 — 5,441 (9 ) 7,877 Other income — 716 163 — 879 Revenue from contracts with customers 5,460 19,750 21,685 53 46,948 Non-interest income within the scope of other GAAP topics 7,072 — 6,373 4,158 17,603 Total non-interest income $ 12,532 $ 19,750 $ 28,058 $ 4,211 $ 64,551 Six months ended June 30, 2018 (In thousands) Commercial HSA Community Corporate and Consolidated Major Revenue Streams Deposit service fees $ 6,402 $ 43,818 $ 30,972 $ 118 $ 81,310 Wealth and investment services 5,126 — 11,217 (17 ) 16,326 Other income — 1,733 1,133 — 2,866 Revenue from contracts with customers 11,528 45,551 43,322 101 100,502 Non-interest income within the scope of other GAAP topics 18,829 — 8,251 9,539 36,619 Total non-interest income $ 30,357 $ 45,551 $ 51,573 $ 9,640 $ 137,121 Six months ended June 30, 2017 (In thousands) Commercial HSA Community Corporate and Consolidated Major Revenue Streams Deposit service fees $ 5,893 $ 37,518 $ 31,611 $ 176 $ 75,198 Wealth and investment services 4,817 — 10,350 (17 ) 15,150 Other income — 1,503 387 — 1,890 Revenue from contracts with customers 10,710 39,021 42,348 159 92,238 Non-interest income within the scope of other GAAP topics 15,246 — 11,089 9,020 35,355 Total non-interest income $ 25,956 $ 39,021 $ 53,437 $ 9,179 $ 127,593

Commitments and Contingencies (

Commitments and Contingencies (Tables)	6 Months Ended
	Jun. 30, 2018
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 June 30, 2018 At December 31, 2017 Commitments to extend credit $ 5,929,945 $ 5,567,687 Standby letter of credit 206,506 195,902 Commercial letter of credit 44,176 43,200 Total credit-related financial instruments with off-balance sheet risk $ 6,180,627 $ 5,806,789
Reserve For Unfunded Credit Commitments	The following table provides a summary of activity in the reserve for loan repurchases: Three months ended June 30, Six months ended June 30, (In thousands) 2018 2017 2018 2017 Beginning balance $ 664 $ 824 $ 872 $ 790 Provision (benefit) charged to expense 13 19 (190 ) 53 Repurchased loans and settlements charged off (3 ) — (8 ) — Ending balance $ 674 $ 843 $ 674 $ 843 Three months ended June 30, Six months ended June 30, (In thousands) 2018 2017 2018 2017 Beginning balance $ 2,294 $ 2,655 $ 2,362 $ 2,287 Provision (benefit) charged to expense 302 (111 ) 234 257 Ending balance $ 2,596 $ 2,544 $ 2,596 $ 2,544

Summary of Significant Accoun44

Summary of Significant Accounting Policies New Accounting Pronouncements or Change in Accounting Principle (Details) $ in Millions	Jun. 30, 2018USD ($)
ASU No. 2017-08, Receivables - Nonrefundable Fees and Other Costs (Subtopic 310-20) [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Cumulative Effect of Change on Equity or Net Assets	$ (2.8)
ASU No. 2016-01, Financial Instruments - Overall (Subtopic 825-10) [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Cumulative Effect of Change on Equity or Net Assets	$ 1.4

Summary of Significant Accoun45

Summary of Significant Accounting Policies Change in Accounting Estimate (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Change in Accounting Estimate [Line Items]
Deposit insurance	$ 13,687	$ 6,625	$ 20,404	$ 13,357
Corporate, Non-Segment [Member]
Change in Accounting Estimate [Line Items]
Deposit insurance			7,200
Corporate, Non-Segment [Member] | Regulatory Reviews of Filings [Member]
Change in Accounting Estimate [Line Items]
Deposit insurance			$ 7,200

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	Jun. 30, 2018	Dec. 31, 2017
Other Assets [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Consolidated, Carrying Amount, Assets	$ 31	$ 33.5
Accounts Payable and Accrued Liabilities [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Consolidated, Carrying Amount, Liabilities	11.1	17.3
Other Investments [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Consolidated, Carrying Amount, Assets	14.6	13.8
Unfunded Loan Commitment [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount	$ 27.5	$ 22.9

Investment Securities (Summary

Investment Securities (Summary Of Investment Securities) (Detail) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Debt Securities, Available-for-sale [Abstract]
Amortized Cost	$ 2,867,055	$ 2,675,131
Unrealized Gains	3,221	7,173
Unrealized Losses	89,695	44,267
Fair Value	2,780,581	2,638,037
Debt Securities, Held-to-maturity, Fair Value to Amortized Cost [Abstract]
Amortized Cost	4,356,219	4,487,392
Unrealized Gains	12,934	28,413
Unrealized Losses	(143,170)	(59,455)
Fair Value	4,225,983	4,456,350
US Treasury Bill Securities [Member]
Debt Securities, Available-for-sale [Abstract]
Amortized Cost	2,491	1,247
Unrealized Gains	0	0
Unrealized Losses	0	0
Fair Value	2,491	1,247
Agency CMO [Member]
Debt Securities, Available-for-sale [Abstract]
Amortized Cost	271,712	308,989
Unrealized Gains	268	1,158
Unrealized Losses	6,727	3,814
Fair Value	265,253	306,333
Debt Securities, Held-to-maturity, Fair Value to Amortized Cost [Abstract]
Amortized Cost	231,943	260,114
Unrealized Gains	296	664
Unrealized Losses	(7,891)	(4,824)
Fair Value	224,348	255,954
Agency MBS [Member]
Debt Securities, Available-for-sale [Abstract]
Amortized Cost	1,356,988	1,124,960
Unrealized Gains	1,053	2,151
Unrealized Losses	46,200	19,270
Fair Value	1,311,841	1,107,841
Debt Securities, Held-to-maturity, Fair Value to Amortized Cost [Abstract]
Amortized Cost	2,520,455	2,569,735
Unrealized Gains	10,139	16,989
Unrealized Losses	(90,415)	(37,442)
Fair Value	2,440,179	2,549,282
Agency CMBS [Member]
Debt Securities, Available-for-sale [Abstract]
Amortized Cost	618,054	608,276
Unrealized Gains	0	0
Unrealized Losses	35,378	20,250
Fair Value	582,676	588,026
Debt Securities, Held-to-maturity, Fair Value to Amortized Cost [Abstract]
Amortized Cost	677,397	696,566
Unrealized Gains	0	0
Unrealized Losses	(24,594)	(10,011)
Fair Value	652,803	686,555
Non-agency CMBS [Member]
Debt Securities, Available-for-sale [Abstract]
Amortized Cost	373,916	358,984
Unrealized Gains	958	2,157
Unrealized Losses	318	74
Fair Value	374,556	361,067
Debt Securities, Held-to-maturity, Fair Value to Amortized Cost [Abstract]
Amortized Cost	229,265	249,273
Unrealized Gains	551	2,175
Unrealized Losses	(3,419)	(620)
Fair Value	226,397	250,828
CLO [Member]
Debt Securities, Available-for-sale [Abstract]
Amortized Cost	187,697	209,075
Unrealized Gains	538	910
Unrealized Losses	169	134
Fair Value	188,066	209,851
Single issuer trust preferred securities [Member]
Debt Securities, Available-for-sale [Abstract]
Amortized Cost	0	7,096
Unrealized Gains	0	0
Unrealized Losses	0	46
Fair Value	0	7,050
Corporate debt securities [Member]
Debt Securities, Available-for-sale [Abstract]
Amortized Cost	56,197	56,504
Unrealized Gains	404	797
Unrealized Losses	903	679
Fair Value	55,698	56,622
Municipal bonds and notes [Member]
Debt Securities, Held-to-maturity, Fair Value to Amortized Cost [Abstract]
Amortized Cost	697,066	711,381
Unrealized Gains	1,948	8,584
Unrealized Losses	(16,851)	(6,558)
Fair Value	682,163	713,407
Private Label MBS [Member]
Debt Securities, Held-to-maturity, Fair Value to Amortized Cost [Abstract]
Amortized Cost	93	323
Unrealized Gains	0	1
Unrealized Losses	0	0
Fair Value	$ 93	$ 324

Investment Securities (Other Th

Investment Securities (Other Than Temporary Impairment Credit Losses Recognized In Earnings) (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Roll Forward]
Balance of OTTI, beginning of period	$ 1,364	$ 3,231	$ 1,364	$ 3,243
Reduction for securities sold, called	(261)	(126)	(261)	(138)
Balance of OTTI, end of period	1,103	3,231	1,103	3,231
Other than Temporary Impairment, Credit Losses Recognized in Earnings, Additions, Additional Credit Losses	$ 0	$ 126	$ 0	$ 126

Investment Securities (Summar49

Investment Securities (Summary Of Gross Unrealized Losses Not Considered OTTI) (Detail) $ in Thousands	Jun. 30, 2018USD ($)holding	Dec. 31, 2017USD ($)holding
Schedule of Investments [Line Items]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	$ 1,051,195	$ 650,514
Available for sale, Unrealized Losses - Less Than Twelve Months	(21,837)	(4,869)
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	1,192,776	1,265,234
Available for sale, Unrealized Losses - Twelve Months or Longer	$ (67,858)	$ (39,398)
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions | holding	268	212
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	$ 2,243,971	$ 1,915,748
Available for sale, Unrealized Losses - Total	(89,695)	(44,267)
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	2,102,531	1,536,069
Held-to-maturity, Unrealized Losses - Less Than Twelve Months	(58,930)	(13,687)
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	1,573,815	1,655,375
Held-to-maturity, Unrealized Losses, Twelve Months or Longer	$ (84,240)	$ (45,768)
Held-to-maturity, Number of Holdings - Total | holding	574	388
Held-to-maturity, Fair Value - Total	$ 3,676,346	$ 3,191,444
Held-to-maturity, Unrealized Losses - Total	(143,170)	(59,455)
Agency CMO [Member]
Schedule of Investments [Line Items]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	110,795	81,001
Available for sale, Unrealized Losses - Less Than Twelve Months	(1,853)	(449)
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	112,410	119,104
Available for sale, Unrealized Losses - Twelve Months or Longer	$ (4,874)	$ (3,365)
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions | holding	36	27
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	$ 223,205	$ 200,105
Available for sale, Unrealized Losses - Total	(6,727)	(3,814)
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	100,551	98,090
Held-to-maturity, Unrealized Losses - Less Than Twelve Months	(2,735)	(1,082)
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	96,424	106,775
Held-to-maturity, Unrealized Losses, Twelve Months or Longer	$ (5,156)	$ (3,742)
Held-to-maturity, Number of Holdings - Total | holding	24	22
Held-to-maturity, Fair Value - Total	$ 196,975	$ 204,865
Held-to-maturity, Unrealized Losses - Total	(7,891)	(4,824)
Agency MBS [Member]
Schedule of Investments [Line Items]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	645,678	416,995
Available for sale, Unrealized Losses - Less Than Twelve Months	(16,586)	(2,920)
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	552,321	606,021
Available for sale, Unrealized Losses - Twelve Months or Longer	$ (29,614)	$ (16,350)
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions | holding	165	135
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	$ 1,197,999	$ 1,023,016
Available for sale, Unrealized Losses - Total	(46,200)	(19,270)
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	1,085,492	762,107
Held-to-maturity, Unrealized Losses - Less Than Twelve Months	(29,208)	(4,555)
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	1,111,469	1,197,839
Held-to-maturity, Unrealized Losses, Twelve Months or Longer	$ (61,207)	$ (32,887)
Held-to-maturity, Number of Holdings - Total | holding	262	205
Held-to-maturity, Fair Value - Total	$ 2,196,961	$ 1,959,946
Held-to-maturity, Unrealized Losses - Total	(90,415)	(37,442)
Agency CMBS [Member]
Schedule of Investments [Line Items]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	71,430	54,182
Available for sale, Unrealized Losses - Less Than Twelve Months	(2,761)	(851)
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	511,246	533,844
Available for sale, Unrealized Losses - Twelve Months or Longer	$ (32,617)	$ (19,399)
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions | holding	37	36
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	$ 582,676	$ 588,026
Available for sale, Unrealized Losses - Total	(35,378)	(20,250)
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	518,344	576,770
Held-to-maturity, Unrealized Losses - Less Than Twelve Months	(18,421)	(7,599)
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	134,459	109,785
Held-to-maturity, Unrealized Losses, Twelve Months or Longer	$ (6,173)	$ (2,412)
Held-to-maturity, Number of Holdings - Total | holding	56	56
Held-to-maturity, Fair Value - Total	$ 652,803	$ 686,555
Held-to-maturity, Unrealized Losses - Total	(24,594)	(10,011)
Non-agency CMBS [Member]
Schedule of Investments [Line Items]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	145,960	23,869
Available for sale, Unrealized Losses - Less Than Twelve Months	$ (318)	$ (74)
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions | holding	22	6
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	$ 145,960	$ 23,869
Available for sale, Unrealized Losses - Total	(318)	(74)
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	147,266	92,670
Held-to-maturity, Unrealized Losses - Less Than Twelve Months	(3,149)	(413)
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	12,758	14,115
Held-to-maturity, Unrealized Losses, Twelve Months or Longer	$ (270)	$ (207)
Held-to-maturity, Number of Holdings - Total | holding	20	13
Held-to-maturity, Fair Value - Total	$ 160,024	$ 106,785
Held-to-maturity, Unrealized Losses - Total	(3,419)	(620)
CLO [Member]
Schedule of Investments [Line Items]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	41,259	56,335
Available for sale, Unrealized Losses - Less Than Twelve Months	(41)	$ (134)
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	15,029
Available for sale, Unrealized Losses - Twelve Months or Longer	$ (128)
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions | holding	3	3
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	$ 56,288	$ 56,335
Available for sale, Unrealized Losses - Total	(169)	(134)
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		7,050
Available for sale, Unrealized Losses - Less Than Twelve Months		$ (46)
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions | holding		1
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value		$ 7,050
Available for sale, Unrealized Losses - Total		(46)
Corporate Debt Securities [Member]
Schedule of Investments [Line Items]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	36,073	11,082
Available for sale, Unrealized Losses - Less Than Twelve Months	(278)	(395)
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	1,770	6,265
Available for sale, Unrealized Losses - Twelve Months or Longer	$ (625)	$ (284)
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions | holding	5	4
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	$ 37,843	$ 17,347
Available for sale, Unrealized Losses - Total	(903)	(679)
Municipal bonds and notes [Member]
Schedule of Investments [Line Items]
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	250,878	6,432
Held-to-maturity, Unrealized Losses - Less Than Twelve Months	(5,417)	(38)
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	218,705	226,861
Held-to-maturity, Unrealized Losses, Twelve Months or Longer	$ (11,434)	$ (6,520)
Held-to-maturity, Number of Holdings - Total | holding	212	92
Held-to-maturity, Fair Value - Total	$ 469,583	$ 233,293
Held-to-maturity, Unrealized Losses - Total	$ (16,851)	$ (6,558)

Investment Securities (Summar50

Investment Securities (Summary Of Debt Securities By Contractual Maturity) (Detail) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Debt Securities, Available-for-sale, Amortized Cost, Fiscal Year Maturity [Abstract]
Available-for-sale, Amortized Cost - Due in one year or less	$ 23,192
Available-for-sale, Amortized Cost - Due after one year through five years	34,000
Available-for-sale, Amortized Cost - Due after five through ten years	314,281
Available-for-sale, Amortized Cost - Due after ten years	2,495,582
Available-for-sale, Amortized Cost - Total debt securities	2,867,055	$ 2,675,131
Debt Securities, Available-for-sale, Fair Value, Fiscal Year Maturity [Abstract]
Available-for-sale, Fair Value - Due in one year or less	23,191
Available-for-sale, Fair Value - Due after one year through five years	34,083
Available-for-sale, Fair Value - Due after five through ten years	313,644
Available-for-sale, Fair Value - Due after ten years	2,409,663
Debt Securities, Available-for-sale	2,780,581	2,638,037
Debt Securities, Held-to-maturity, Maturity, Allocated and Single Maturity Date, Amortized Cost [Abstract]
Held-to-maturity, Amortized Cost - Due in one year or less	17,891
Held-to-maturity, Amortized Cost - Due after one year through five years	3,628
Held-to-maturity, Amortized Cost - Due after five through ten years	40,865
Held-to-maturity, Amortized Cost - Due after ten years	4,293,835
Amortized Cost	4,356,219	4,487,392
Debt Securities, Held-to-maturity, Maturity, Fair Value [Abstract]
Held to maturity, Fair Value - Due in one year or less	18,013
Held-to-maturity, Fair Value - Due after one year through five years	3,656
Held to maturity, Fair Value - Due after five through ten years	40,977
Held to maturity, Fair Value - Due after ten years	4,163,337
Fair Value	$ 4,225,983	$ 4,456,350

Investment Securities Investmen

Investment Securities Investment Securities (Narrative) (Detail) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Debt Securities, Available-for-sale [Abstract]
Unrealized Losses	$ 89,695	$ 44,267
Debt Securities, Held-to-maturity, Fair Value to Amortized Cost [Abstract]
Unrealized Losses	(143,170)	(59,455)
Investment securities available-for-sale, at fair value	2,780,581	2,638,037
Pledged Financial Instruments, Not Separately Reported, Securities	2,400,000
Agency CMO [Member]
Debt Securities, Available-for-sale [Abstract]
Unrealized Losses	6,727	3,814
Debt Securities, Held-to-maturity, Fair Value to Amortized Cost [Abstract]
Unrealized Losses	(7,891)	(4,824)
Agency MBS [Member]
Debt Securities, Available-for-sale [Abstract]
Unrealized Losses	46,200	19,270
Debt Securities, Held-to-maturity, Fair Value to Amortized Cost [Abstract]
Unrealized Losses	(90,415)	(37,442)
Agency CMBS [Member]
Debt Securities, Available-for-sale [Abstract]
Unrealized Losses	35,378	20,250
Debt Securities, Held-to-maturity, Fair Value to Amortized Cost [Abstract]
Unrealized Losses	(24,594)	(10,011)
Non-agency CMBS [Member]
Debt Securities, Available-for-sale [Abstract]
Unrealized Losses	318	74
Debt Securities, Held-to-maturity, Fair Value to Amortized Cost [Abstract]
Unrealized Losses	(3,419)	(620)
CLO [Member]
Debt Securities, Available-for-sale [Abstract]
Unrealized Losses	169	134
Single issuer trust preferred securities [Member]
Debt Securities, Available-for-sale [Abstract]
Unrealized Losses	0	46
Corporate Debt Securities [Member]
Debt Securities, Available-for-sale [Abstract]
Unrealized Losses	903	679
Municipal Bonds [Member]
Debt Securities, Held-to-maturity, Fair Value to Amortized Cost [Abstract]
Unrealized Losses	(16,851)	$ (6,558)
Callable at the option of the counterparty [Member]
Debt Securities, Held-to-maturity, Fair Value to Amortized Cost [Abstract]
Investment securities available-for-sale, at fair value	$ 1,300,000

Investment Securities (Narrativ

Investment Securities (Narrative) (Summary Of Realized Gain (Loss) on Investments (Detail) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Gain (Loss) on Investments [Line Items]
Proceeds from Sale of Debt Securities, Available-for-sale	$ 0	$ 0

Loans and Leases (Detail)

Loans and Leases (Detail) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017	Jun. 30, 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	$ 18,025,996	$ 17,523,858	$ 17,273,678
Unamortized premiums	16,400	20,600
Pledged Financial Instruments, Not Separately Reported, Loans Receivable Pledged as Collateral	6,500,000
Residential Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	4,455,580	4,490,878	4,388,308
Consumer Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	2,485,695	2,590,225	2,599,318
Commercial Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	5,981,556	5,368,694	5,144,171
Commercial Real Estate Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	4,580,200	4,523,828	4,556,208
Finance Leases Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	$ 522,965	$ 550,233	$ 585,673

Loans and Leases (Summary Of Lo

Loans and Leases (Summary Of Loan And Lease Portfolio Aging By Class Of Loan) (Detail) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017	Jun. 30, 2017
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	$ 173,763	$ 172,360
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing	62	892
Financing Receivable, Recorded Investment, Nonaccrual Status	140,178	126,513
Financing Receivable, Recorded Investment, Current	17,852,233	17,351,498
Loans and leases	18,025,996	17,523,858	$ 17,273,678
Financing Receivables, 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	22,716	31,289
Financing Receivables, 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	10,807	13,666
Residential Portfolio Segment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	61,678	58,270
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing	0	0
Financing Receivable, Recorded Investment, Nonaccrual Status	50,780	44,481
Financing Receivable, Recorded Investment, Current	4,393,902	4,432,608
Loans and leases	4,455,580	4,490,878	4,388,308
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	6,449	8,643
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	4,449	5,146
Consumer Portfolio Segment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases	2,485,695	2,590,225	2,599,318
Consumer Portfolio Segment [Member] | Home Equity Loan [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	48,157	54,083
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing	0	0
Financing Receivable, Recorded Investment, Nonaccrual Status	36,849	35,645
Financing Receivable, Recorded Investment, Current	2,208,522	2,298,185
Loans and leases	2,256,679	2,352,268
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	8,286	12,668
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	3,022	5,770
Consumer Portfolio Segment [Member] | Consumer Borrower [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	4,658	5,707
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing	0	0
Financing Receivable, Recorded Investment, Nonaccrual Status	1,583	1,707
Financing Receivable, Recorded Investment, Current	224,358	232,250
Loans and leases	229,016	237,957
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	1,860	2,556
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	1,215	1,444
Commercial Portfolio Segment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases	5,981,556	5,368,694	5,144,171
Commercial Portfolio Segment [Member] | Commercial and Industrial Sector [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	41,949	45,673
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing	62	644
Financing Receivable, Recorded Investment, Nonaccrual Status	36,687	39,214
Financing Receivable, Recorded Investment, Current	4,979,771	4,488,242
Loans and leases	5,021,720	4,533,915
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	3,410	5,212
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	1,790	603
Commercial Portfolio Segment [Member] | Asset Based Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	1,160	589
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing	0	0
Financing Receivable, Recorded Investment, Nonaccrual Status	1,160	589
Financing Receivable, Recorded Investment, Current	958,676	834,190
Loans and leases	959,836	834,779
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	4,580,200	4,523,828	4,556,208
Commercial Real Estate Portfolio Segment [Member] | Construction Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	0	0
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing	0	0
Financing Receivable, Recorded Investment, Nonaccrual Status	0	0
Financing Receivable, Recorded Investment, Current	158,268	279,554
Loans and leases	158,268	279,554
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	10,329	5,287
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing	0	248
Financing Receivable, Recorded Investment, Nonaccrual Status	9,609	4,484
Financing Receivable, Recorded Investment, Current	4,411,603	4,238,987
Loans and leases	4,421,932	4,244,274
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	720	478
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	0	77
Finance Leases Portfolio Segment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	5,832	2,751
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing	0	0
Financing Receivable, Recorded Investment, Nonaccrual Status	3,510	393
Financing Receivable, Recorded Investment, Current	517,133	547,482
Loans and leases	522,965	550,233	$ 585,673
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	1,991	1,732
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	$ 331	$ 626

Loans and Leases (Narrative) (D

Loans and Leases (Narrative) (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Loans and Leases Receivable Disclosure [Abstract]
Loans and Leases Receivable, Impaired, Interest Lost on Nonaccrual Loans	$ 2.4	$ 2.6	$ 4.3	$ 4.5
Write-down of TDR's	$ (4.5)	$ (0.6)	$ (5.2)	$ (2.6)

Loans and Leases (Allowance For

Loans and Leases (Allowance For Loan And Lease Losses By Portfolio Segment) (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Dec. 31, 2017	Jun. 30, 2017
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivables, Impaired, Troubled Debt Restructuring, Write-down	$ 4,500	$ 600	$ 5,200	$ 2,600
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance, beginning of period	205,349	199,107	199,994	194,320
Provision (benefit) charged to expense	10,500	7,250	21,500	17,750
Charge-offs	(11,398)	(8,640)	(19,008)	(16,256)
Recoveries	2,871	1,861	4,836	3,764
Balance, end of period	205,349	199,107	199,994	194,320	$ 207,322	$ 199,994	$ 199,578
ALLL, Individually evaluated for impairment					13,914		18,236
ALLL, Collectively evaluated for impairment					193,408		181,342
Loan and lease balances, Individually evaluated for impairment					257,205		273,345
Loan and lease balances, Collectively evaluated for impairment					17,768,791		17,000,333
Loans and leases					18,025,996	17,523,858	17,273,678
Residential Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance, beginning of period	18,777	20,264	19,058	23,226
Provision (benefit) charged to expense	659	(1,621)	909	(4,088)
Charge-offs	(754)	(623)	(1,671)	(1,355)
Recoveries	325	407	711	644
Balance, end of period	18,777	20,264	19,058	23,226	19,007	19,058	18,427
ALLL, Individually evaluated for impairment					4,330		5,105
ALLL, Collectively evaluated for impairment					14,677		13,322
Loan and lease balances, Individually evaluated for impairment					109,636		117,820
Loan and lease balances, Collectively evaluated for impairment					4,345,944		4,270,488
Loans and leases					4,455,580	4,490,878	4,388,308
Consumer Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance, beginning of period	34,239	45,408	36,190	45,233
Provision (benefit) charged to expense	813	1,562	2,493	6,888
Charge-offs	(4,907)	(5,602)	(9,981)	(12,076)
Recoveries	1,614	1,120	3,057	2,443
Balance, end of period	34,239	45,408	36,190	45,233	31,759	36,190	42,488
ALLL, Individually evaluated for impairment					1,498		1,829
ALLL, Collectively evaluated for impairment					30,261		40,659
Loan and lease balances, Individually evaluated for impairment					41,636		47,310
Loan and lease balances, Collectively evaluated for impairment					2,444,059		2,552,008
Loans and leases					2,485,695	2,590,225	2,599,318
Commercial Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance, beginning of period	95,573	76,354	89,533	71,905
Provision (benefit) charged to expense	4,490	5,489	11,910	9,739
Charge-offs	(5,632)	(2,196)	(7,129)	(2,319)
Recoveries	909	317	1,026	639
Balance, end of period	95,573	76,354	89,533	71,905	95,340	89,533	79,964
ALLL, Individually evaluated for impairment					6,007		10,951
ALLL, Collectively evaluated for impairment					89,333		69,013
Loan and lease balances, Individually evaluated for impairment					87,071		83,206
Loan and lease balances, Collectively evaluated for impairment					5,894,485		5,060,965
Loans and leases					5,981,556	5,368,694	5,144,171
Commercial Real Estate Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance, beginning of period	51,436	50,727	49,407	47,477
Provision (benefit) charged to expense	4,428	1,771	6,532	5,116
Charge-offs	(40)	(100)	(117)	(202)
Recoveries	9	4	11	11
Balance, end of period	51,436	50,727	49,407	47,477	55,833	49,407	52,402
ALLL, Individually evaluated for impairment					2,061		324
ALLL, Collectively evaluated for impairment					53,772		52,078
Loan and lease balances, Individually evaluated for impairment					12,677		18,677
Loan and lease balances, Collectively evaluated for impairment					4,567,523		4,537,531
Loans and leases					4,580,200	4,523,828	4,556,208
Finance Leases Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance, beginning of period	5,324	6,354	5,806	6,479
Provision (benefit) charged to expense	110	49	(344)	95
Charge-offs	(65)	(119)	(110)	(304)
Recoveries	14	13	31	27
Balance, end of period	$ 5,324	$ 6,354	$ 5,806	$ 6,479	5,383	5,806	6,297
ALLL, Individually evaluated for impairment					18		27
ALLL, Collectively evaluated for impairment					5,365		6,270
Loan and lease balances, Individually evaluated for impairment					6,185		6,332
Loan and lease balances, Collectively evaluated for impairment					516,780		579,341
Loans and leases					$ 522,965	$ 550,233	$ 585,673

Loans and Leases (Impaired Loan

Loans and Leases (Impaired Loans And Leases By Class) (Detail) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	$ 286,888	$ 274,736
Total Recorded Investment	257,205	246,753
Recorded Investment No Allowance	163,280	141,398
Recorded Investment With Allowance	93,925	105,355
Related Valuation Allowance	13,914	16,554
Residential Portfolio Segment [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	120,019	125,352
Total Recorded Investment	109,636	114,295
Recorded Investment No Allowance	68,854	69,759
Recorded Investment With Allowance	40,782	44,536
Related Valuation Allowance	4,330	4,805
Consumer Portfolio Segment [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance		50,809
Total Recorded Investment		45,436
Recorded Investment No Allowance		34,418
Recorded Investment With Allowance		11,018
Related Valuation Allowance		1,668
Consumer Portfolio Segment [Member] | Home Equity Loan [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	46,758
Total Recorded Investment	41,636
Recorded Investment No Allowance	32,140
Recorded Investment With Allowance	9,496
Related Valuation Allowance	1,498
Commercial Portfolio Segment [Member] | Commercial and Industrial Sector [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	99,170	79,900
Total Recorded Investment	85,911	71,882
Recorded Investment No Allowance	52,522	27,313
Recorded Investment With Allowance	33,389	44,569
Related Valuation Allowance	6,007	9,786
Commercial Portfolio Segment [Member] | Asset Based Loans [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	1,197	3,272
Total Recorded Investment	1,160	589
Recorded Investment No Allowance	1,160	589
Recorded Investment With Allowance	0	0
Related Valuation Allowance	0	0
Commercial Real Estate Portfolio Segment [Member] | Real Estate Loan [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	13,490	11,994
Total Recorded Investment	12,677	11,226
Recorded Investment No Allowance	2,812	6,387
Recorded Investment With Allowance	9,865	4,839
Related Valuation Allowance	2,061	272
Commercial Real Estate Portfolio Segment [Member] | Construction Loans [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	0	0
Total Recorded Investment	0	0
Recorded Investment No Allowance	0	0
Recorded Investment With Allowance	0	0
Related Valuation Allowance	0	0
Finance Leases Portfolio Segment [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	6,254	3,409
Total Recorded Investment	6,185	3,325
Recorded Investment No Allowance	5,792	2,932
Recorded Investment With Allowance	393	393
Related Valuation Allowance	$ 18	$ 23

Loans and Leases (Interest Inco

Loans and Leases (Interest Income From Impaired Loans And Leases, By Class) (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	$ 252,843	$ 279,256	$ 251,978	$ 261,350
Accrued Interest Income	2,182	1,769	4,128	3,601
Cash Basis Interest Income	515	535	1,018	1,263
Residential Portfolio Segment [Member]
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	110,787	119,398	111,965	118,622
Accrued Interest Income	948	1,036	1,929	2,106
Cash Basis Interest Income	265	286	518	701
Consumer Portfolio Segment [Member] | Home Equity Loan [Member]
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	42,112	47,296	43,536	46,514
Accrued Interest Income	290	335	584	657
Cash Basis Interest Income	250	249	500	562
Commercial Portfolio Segment [Member] | Commercial and Industrial Sector [Member]
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	80,475	85,006	78,896	68,122
Accrued Interest Income	871	233	1,410	455
Cash Basis Interest Income	0	0	0	0
Commercial Portfolio Segment [Member] | Asset Based Loans [Member]
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	1,347	0	875	0
Accrued Interest Income	0	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	11,802	20,454	11,951	20,851
Accrued Interest Income	38	98	134	233
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	0	862	0	865
Accrued Interest Income	0	0	0	12
Cash Basis Interest Income	0	0	0	0
Finance Leases Portfolio Segment [Member]
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	6,320	6,240	4,755	6,376
Accrued Interest Income	35	67	71	138
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	Jun. 30, 2018	Dec. 31, 2017	Jun. 30, 2017
Financing Receivable, Recorded Investment [Line Items]
Loans and leases	$ 18,025,996	$ 17,523,858	$ 17,273,678
Commercial Portfolio Segment [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases	5,981,556	5,368,694	5,144,171
Commercial Portfolio Segment [Member] | (1) - (6) Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases	5,574,419	5,048,162
Commercial Portfolio Segment [Member] | (7) Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases	172,017	104,594
Commercial Portfolio Segment [Member] | (8) Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases	226,275	206,883
Commercial Portfolio Segment [Member] | (9) Doubtful [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases	8,845	9,055
Commercial Real Estate Portfolio Segment [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases	4,580,200	4,523,828	4,556,208
Commercial Real Estate Portfolio Segment [Member] | (1) - (6) Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases	4,422,144	4,355,916
Commercial Real Estate Portfolio Segment [Member] | (7) Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases	48,683	62,065
Commercial Real Estate Portfolio Segment [Member] | (8) Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases	109,373	105,847
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	522,965	550,233	$ 585,673
Finance Leases Portfolio Segment [Member] | (1) - (6) Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases	497,193	525,105
Finance Leases Portfolio Segment [Member] | (7) Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases	6,490	8,022
Finance Leases Portfolio Segment [Member] | (8) Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases	19,282	17,106
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	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016
Financing Receivable, Modifications [Line Items]
Total recorded investment of TDRs	$ 229,974		$ 221,404
Specific reserves for TDRs included in the balance of ALLL	207,322	$ 205,349	199,994	$ 199,578	$ 199,107	$ 194,320
Additional funds committed to borrowers in TDR status	7,206		2,736
Performing Financial Instruments [Member]
Financing Receivable, Modifications [Line Items]
Total recorded investment of TDRs	150,459		147,113
Nonperforming Financial Instruments [Member]
Financing Receivable, Modifications [Line Items]
Total recorded investment of TDRs	79,515		74,291
Nonperforming Financial Instruments [Member] | Troubled Debt Restructures [Member]
Financing Receivable, Modifications [Line Items]
Specific reserves for TDRs included in the balance of ALLL	$ 11,334		$ 12,384

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		6 Months Ended
	Jun. 30, 2018USD ($)loan	Jun. 30, 2017USD ($)loan	Jun. 30, 2018USD ($)loan	Jun. 30, 2017USD ($)loan
Financing Receivable, Modifications [Line Items]
Number of Loans and Leases | loan	38	44	64	116
Post-Modification Recorded Investment | $	$ 32,729	$ 14,073	$ 39,384	$ 22,727
Home Equity Loan [Member] | Contractual Interest Rate Reduction [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans and Leases | loan	0	0
Post-Modification Recorded Investment | $	$ 0	$ 0
Residential Portfolio Segment [Member] | Extended Maturity [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans and Leases | loan	0	4	0	9
Post-Modification Recorded Investment | $	$ 0	$ 420	$ 0	$ 1,390
Residential Portfolio Segment [Member] | Contractual Interest Rate Reduction [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans and Leases | loan	0	2	0	2
Post-Modification Recorded Investment | $	$ 0	$ 335	$ 0	$ 335
Residential Portfolio Segment [Member] | Maturity/Rate Combined [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans and Leases | loan	3	2	3	5
Post-Modification Recorded Investment | $	$ 276	$ 354	$ 276	$ 846
Residential Portfolio Segment [Member] | Other [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans and Leases | loan	8	7	13	26
Post-Modification Recorded Investment | $	$ 1,685	$ 1,176	$ 2,442	$ 4,114
Consumer Portfolio Segment [Member] | Contractual Interest Rate Reduction [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans and Leases | loan			0	0
Post-Modification Recorded Investment | $			$ 0	$ 0
Consumer Portfolio Segment [Member] | Home Equity Loan [Member] | Extended Maturity [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans and Leases | loan	0	4	2	6
Post-Modification Recorded Investment | $	$ 0	$ 625	$ 193	$ 664
Consumer Portfolio Segment [Member] | Home Equity Loan [Member] | Maturity/Rate Combined [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans and Leases | loan	1	4	3	11
Post-Modification Recorded Investment | $	$ 335	$ 830	$ 448	$ 2,813
Consumer Portfolio Segment [Member] | Home Equity Loan [Member] | Other [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans and Leases | loan	14	10	25	43
Post-Modification Recorded Investment | $	$ 915	$ 701	$ 1,693	$ 2,894
Commercial Portfolio Segment [Member] | Contractual Interest Rate Reduction [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans and Leases | loan	0	0	0	0
Post-Modification Recorded Investment | $	$ 0	$ 0	$ 0	$ 0
Commercial Portfolio Segment [Member] | Commercial and Industrial Sector [Member] | Extended Maturity [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans and Leases | loan	0	6	3	8
Post-Modification Recorded Investment | $	$ 0	$ 778	$ 85	$ 813
Commercial Portfolio Segment [Member] | Commercial and Industrial Sector [Member] | Maturity/Rate Combined [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans and Leases | loan	2	5	2	5
Post-Modification Recorded Investment | $	$ 51	$ 8,854	$ 51	$ 8,854
Commercial Portfolio Segment [Member] | Commercial and Industrial Sector [Member] | Other [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans and Leases | loan	7	0	9	1
Post-Modification Recorded Investment | $	$ 24,059	$ 0	$ 28,743	$ 4
Commercial Real Estate Portfolio Segment [Member] | Real Estate Loan [Member] | Extended Maturity [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans and Leases | loan	1	0	2	0
Post-Modification Recorded Investment | $	$ 52	$ 0	$ 97	$ 0
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	1	0	1	0
Post-Modification Recorded Investment | $	$ 245	$ 0	$ 245	$ 0
Commercial Real Estate Portfolio Segment [Member] | Real Estate Loan [Member] | Other [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans and Leases | loan	1	0	1	0
Post-Modification Recorded Investment | $	$ 5,111	$ 0	$ 5,111	$ 0
Finance Leases Portfolio Segment [Member] | Extended Maturity [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans and Leases | loan	0	0	0	0
Post-Modification Recorded Investment | $	$ 0	$ 0	$ 0	$ 0

Loans and Leases (Information62

Loans and Leases (Information on Loans and Leases Modified as TDR within the Previous 12 Months with payment default) (Narrative) (Detail)	6 Months Ended
	Jun. 30, 2018USD ($)
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Subsequent Default, Recorded Investment	$ 0

Loans and Leases (Investments i

Loans and Leases (Investments in TDRs, Segregated by Risk Rating Exposure) (Detail) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Financing Receivable, Modifications [Line Items]
Total recorded investment of TDRs	$ 229,974	$ 221,404
Commerial, Commercial Real Estate, Equipment Financing TDR's [Member]
Financing Receivable, Modifications [Line Items]
Total recorded investment of TDRs	78,701	61,673
Commerial, Commercial Real Estate, Equipment Financing TDR's [Member] | (1) - (6) Pass [Member]
Financing Receivable, Modifications [Line Items]
Total recorded investment of TDRs	3,886	8,268
Commerial, Commercial Real Estate, Equipment Financing TDR's [Member] | (7) Special Mention [Member]
Financing Receivable, Modifications [Line Items]
Total recorded investment of TDRs	14,109	355
Commerial, Commercial Real Estate, Equipment Financing TDR's [Member] | (8) Substandard [Member]
Financing Receivable, Modifications [Line Items]
Total recorded investment of TDRs	60,706	53,050
Commerial, Commercial Real Estate, Equipment Financing TDR's [Member] | (9) Doubtful [Member]
Financing Receivable, Modifications [Line Items]
Total recorded investment of TDRs	$ 0	$ 0

Transfers of Financial Assets64

Transfers of Financial Assets (Reserve for loan repurchases) (Detail) - SEC Schedule, 12-09, Reserve, Off-balance Sheet Activity [Member] - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Beginning balance	$ 664	$ 824	$ 872	$ 790
Provision (benefit) charged to expense	13	19	(190)	53
Repurchased loans and settlements charged off	(3)	0	(8)	0
Ending balance	$ 674	$ 843	$ 674	$ 843

Transfers of Financial Assets65

Transfers of Financial Assets (Loans sold) (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Net gain on sale	$ 1,235	$ 3,351	$ 2,379	$ 5,617
Residential Mortgage [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Proceeds from sale	45,257	66,718	90,063	173,338
Loans sold with servicing rights retained	39,822	60,167	79,726	159,667
Net gain on sale	598	2,126	1,681	2,377
Ancillary Fee Income Generated by Servicing Financial Assets, Amount	402	641	812	1,409
Fair value option adjustment	$ 235	$ 584	$ (114)	$ 1,831

Transfers of Financial Assets66

Transfers of Financial Assets (Mortgage Servicing Assets) (Narrative) (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Securitization or Asset-backed Financing Arrangement, Financial Asset for which Transfer is Accounted as Sale [Line Items]
Proceeds from loans not originated for sale			$ 34	$ 7,445
Residential Mortgage [Member]
Securitization or Asset-backed Financing Arrangement, Financial Asset for which Transfer is Accounted as Sale [Line Items]
Retained servicing rights	$ 2,500,000		2,500,000		$ 2,600,000
Contractually Specified Servicing Fees, Amount	$ 300	$ 200	600	400
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			$ 34

Transfers of Financial Assets S

Transfers of Financial Assets Servicing Assets at Amortized Cost Roll Forward (Details) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Servicing Asset at Amortized Cost, Balance [Roll Forward]
Beginning Balance	$ 24,403	$ 24,336	$ 25,139	$ 24,466
Additions	1,038	2,478	2,450	4,487
Amortization	(2,100)	(2,106)	(4,248)	(4,245)
Ending Balance	$ 23,341	$ 24,708	$ 23,341	$ 24,708

Goodwill and Other Intangible68

Goodwill and Other Intangible Assets (Gross Carrying Value And Accumulated Amortization Of Other Intangible Assets) (Detail) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Finite-Lived Intangible Assets [Line Items]
Goodwill	$ 538,373	$ 538,373
Gross Carrying Amount	43,000	43,000
Accumulated Amortization	(15,312)	(13,389)
Net Carrying Amount	27,688	29,611
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	(9,725)	(8,610)
Net Carrying Amount	12,275	13,390
Customer Relationships [Member] | HSA Bank [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	21,000	21,000
Accumulated Amortization	(5,587)	(4,779)
Net Carrying Amount	$ 15,413	$ 16,221

Goodwill and Other Intangible69

Goodwill and Other Intangible Assets (Schedule Of Expected Future Amortization Expense) (Detail) $ in Thousands	Jun. 30, 2018USD ($)
Goodwill and Intangible Assets Disclosure [Abstract]
Remainder of 2018	$ 1,924
2,019	3,847
2,020	3,847
2,021	3,847
2,022	3,847
Thereafter	$ 10,376

Deposits (Summary Of Deposits)

Deposits (Summary Of Deposits) (Detail) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Non-interest-bearing:
Demand	$ 4,151,259	$ 4,191,496
Interest-bearing:
HSA	5,517,929	5,038,681
Checking	2,637,346	2,736,952
Money market	2,016,453	2,209,492
Savings	4,180,666	4,348,700
Time deposits	2,839,703	2,468,408
Total interest-bearing	17,192,097	16,802,233
Total deposits	21,343,356	20,993,729
Time deposits and interest-bearing checking, included in above balances, obtained through brokers	936,830	898,157
Time deposits, included in above balance, that meet or exceed the FDIC limit	888,419	561,512
Deposit overdrafts reclassified as loan balances	$ 3,587	$ 2,210

Deposits (Scheduled Maturities

Deposits (Scheduled Maturities Of Time Deposits) (Detail) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Banking and Thrift [Abstract]
Remainder of 2017	$ 1,016,354
2,018	1,313,184
2,019	314,856
2,020	122,427
2,021	47,641
Thereafter	25,241
Total time deposits	$ 2,839,703	$ 2,468,408

Borrowings Borrowings - (Narrat

Borrowings Borrowings - (Narrative) (Details) - USD ($) $ in Billions	Jun. 30, 2018	Dec. 31, 2017
Debt Disclosure [Abstract]
Total borrowings	$ 2.7	$ 2.5

Borrowings (Summary Of Securiti

Borrowings (Summary Of Securities Sold Under Agreements To Repurchase And Other Borrowings) (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Assets Sold under Agreements to Repurchase [Line Items]
Securities sold under agreements to repurchase	$ 557,568	$ 588,269
Fed funds purchased	305,000	55,000
Securities sold under agreements to repurchase and other borrowings	$ 862,568	$ 643,269
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	1.78%	1.66%
Federal Funds Purchased [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Short-term Debt, Weighted Average Interest Rate, at Point in Time	1.99%	1.37%
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	1.86%	1.64%
Original maturity of one year or less [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Securities sold under agreements to repurchase	$ 257,568	$ 288,269
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	0.25%	0.17%
Original maturity of greater than one year, non-callable [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Securities sold under agreements to repurchase	$ 300,000	$ 300,000
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	3.10%	3.10%

Borrowings (Federal Home Loan A

Borrowings (Federal Home Loan Advances) (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Federal Home Loan Bank, Advances, Weighted Average Interest Rate [Abstract]
FHLB advances maturing within 1 year, Weighted Average Contractual Coupon Rate (as a percent)	1.99%	1.48%
FHLB advances maturing after 1 but within 2 years, Weighted Average Contractual Coupon Rate (as a percent)	1.78%	1.81%
FHLB advances maturing after 2 but within 3 years, Weighted Average Contractual Coupon Rate (as a percent)	1.71%	1.73%
FHLB advances maturing after 3 but within 4 years, Weighted Average Contractual Coupon Rate (as a percent)	3.24%	2.06%
FHLB advances maturing after 4 but within 5 years, Weighted Average Contractual Coupon Rate (as a percent)	0.00%	0.00%
FHLB advances maturing after 5 years, Weighted Average Contractual Coupon Rate (as a percent)	2.65%	2.65%
Federal Home Loan Bank, Advances, Weighted Average Contractual Coupon Rate (as a percent)	2.06%	1.61%
Federal Home Loan Bank, Advances, Maturity, Rolling Year [Abstract]
FHLB advances maturing within 1 year, Total Outstanding	$ 1,075,000	$ 1,150,000
FHLB advances maturing after 1 but within 2 years, Total Outstanding	153,026	103,026
FHLB advances maturing after 2 but within 3 years, Total Outstanding	190,000	215,000
FHLB advances maturing after 3 but within 4 years, Total Outstanding	150,000	200,000
FHLB advances maturing after 4 but within 5 years, Total Outstanding	160	170
FHLB advances maturing after 5 years, Total Outstanding	8,770	8,909
Federal Home Loan Bank, Advances	1,576,956	1,677,105
Pledged Financial Instruments, Not Separately Reported, Loans Receivable, for Federal Home Loan Bank Debt	6,216,042	6,402,066
Remaining borrowing capacity	$ 2,610,327	$ 2,600,624
Previously Reported [Member]
Federal Home Loan Bank, Advances, Weighted Average Interest Rate [Abstract]
FHLB advances maturing after 3 but within 4 years, Weighted Average Contractual Coupon Rate (as a percent)		4.13%
FHLB advances maturing after 5 years, Weighted Average Contractual Coupon Rate (as a percent)		1.96%
Federal Home Loan Bank, Advances, Weighted Average Contractual Coupon Rate (as a percent)		1.85%

Borrowings (Long Term Debt) (De

Borrowings (Long Term Debt) (Details) - USD ($)		Jun. 30, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Notes and subordinated debt		$ 227,320,000	$ 227,320,000
Debt issuance cost on senior fixed-rates		(759,000)	(826,000)
Long-term debt		$ 225,894,000	$ 225,767,000
Variable interest rate		5.28%	4.55%
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		$ (667,000)	$ (727,000)
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 London Interbank Offered Rate plus 2.95% , was 5.28% at June 30, 2018 and 4.55% at December 31, 2017

Accumulated Other Comprehensi76

Accumulated Other Comprehensive Loss, Net of Tax (Schedule of Other Comprehensive Income (Loss)) (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance			$ 2,701,958	$ 2,527,012
Other comprehensive income (loss), net of tax	$ (6,457)	$ 4,945	(30,405)	4,911
Ending Balance	2,761,723	2,605,126	2,761,723	2,605,126
Available For Sale and Transferred Securities [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	(55,371)	(17,701)	(27,947)	(15,476)
(OCL) OCI before reclassifications	(9,246)	3,200	(36,670)	975
Amounts reclassified from AOCL	0	0	0	0
Other comprehensive income (loss), net of tax	(9,246)	3,200	(36,670)	975
Ending Balance	(64,617)	(14,501)	(64,617)	(14,501)
Derivative Instruments [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	(12,494)	(15,909)	(15,016)	(17,068)
(OCL) OCI before reclassifications	294	(472)	1,423	(411)
Amounts reclassified from AOCL	1,386	1,123	2,779	2,221
Other comprehensive income (loss), net of tax	1,680	651	4,202	1,810
Ending Balance	(10,814)	(15,258)	(10,814)	(15,258)
Defined Benefit Pension and Other Postretirement Benefit Plans [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	(47,614)	(43,417)	(48,568)	(44,449)
(OCL) OCI before reclassifications	0	0	0	0
Amounts reclassified from AOCL	1,109	1,094	2,063	2,126
Other comprehensive income (loss), net of tax	1,109	1,094	2,063	2,126
Ending Balance	(46,505)	(42,323)	(46,505)	(42,323)
AOCI Attributable to Parent [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	(115,479)	(77,027)	(91,531)	(76,993)
(OCL) OCI before reclassifications	(8,952)	2,728	(35,247)	564
Amounts reclassified from AOCL	2,495	2,217	4,842	4,347
Other comprehensive income (loss), net of tax	(6,457)	4,945	(30,405)	4,911
Ending Balance	$ (121,936)	$ (72,082)	$ (121,936)	$ (72,082)

Accumulated Other Comprehensi77

Accumulated Other Comprehensive Loss, Net of Tax (Schedule of Accumulated Other Comprehensive Loss) (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Income tax expense	$ (20,743)	$ (29,090)	$ (40,818)	$ (51,041)
Earnings applicable to common shareholders	79,489	59,485	157,573	116,826
Accumulated Net Investment Gain (Loss) Attributable to Parent [Member]
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Net of tax	0	0	0	0
Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member]
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Net of tax	(1,386)	(1,123)	(2,779)	(2,221)
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	475	648	953	1,285
Earnings applicable to common shareholders	(1,386)	(1,123)	(2,779)	(2,221)
Total interest expense	(1,861)	(1,771)	(3,732)	(3,506)
Accumulated Defined Benefit Plans Adjustment, Net Unamortized Gain (Loss) [Member]
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Total before tax	(1,493)	(1,734)	(2,778)	(3,372)
Defined benefit pension and postretirement benefit plans [Member]
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Income tax expense	384	640	715	1,246
Net of tax	$ (1,109)	$ (1,094)	$ (2,063)	$ (2,126)

Regulatory Matters (Information

Regulatory Matters (Information On The Capital Ratios) (Detail) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Common Equity Tier One Capital	$ 2,148,786		$ 2,093,116
Common Equity Tier One Capital Ratio	10.99%		11.14%
Common Equity Tier One Capital Required for Capital Adequacy	$ 879,461		$ 845,389
Common Equity Tier One Capital Required to be Well-Capitalized	1,270,333		1,221,118
Total risk-based capital, Actual Amount	$ 2,581,061		$ 2,517,848
Total risk-based capital, Actual Ratio	13.21%		13.40%
Total risk-based capital, Capital Requirements, Minimum Amount	$ 1,563,486		$ 1,502,914
Total risk-based capital, Capital Requirements, Minimum Ratio	8.00%		8.00%
Total risk-based capital, Capital Requirements, Well Capitalized Amount	$ 1,954,358		$ 1,878,643
Total risk-based capital, Capital Requirements, Well Capitalized Ratio	10.00%		10.00%
Tier 1 capital, Actual Amount	$ 2,293,823		$ 2,238,172
Tier 1 capital, Actual Ratio	11.74%		11.91%
Tier 1 capital, Capital Requirements, Minimum Amount	$ 1,172,615		$ 1,127,186
Tier 1 capital, Capital Requirements, Minimum Ratio	6.00%		6.00%
Tier 1 capital, Capital Requirements, Well Capitalized Amount	$ 1,563,486		$ 1,502,914
Tier 1 capital, Capital Requirements, Well Capitalized Ratio	8.00%		8.00%
Tier 1 leverage capital ratio, Actual Amount	$ 2,293,823		$ 2,238,172
Tier 1 leverage capital ratio, Actual Ratio	8.70%		8.63%
Tier 1 leverage capital ratio, Capital Requirements, Minimum Amount	$ 1,054,648		$ 1,036,817
Tier 1 leverage capital ratio, Capital Requirements, Minimum Ratio	4.00%		4.00%
Tier 1 leverage capital ratio, Capital Requirements, Well Capitalized Amount	$ 1,318,310		$ 1,296,021
Tier 1 leverage capital ratio, Capital Requirements, Well Capitalized Ratio	5.00%		5.00%
Dividends paid	$ 150,000	$ 30,000
Subsidiaries [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Common Equity Tier One Capital	$ 2,100,537		$ 2,114,224
Common Equity Tier One Capital Ratio	10.76%		11.26%
Common Equity Tier One Capital Required for Capital Adequacy	$ 878,786		$ 844,693
Common Equity Tier One Capital Required to be Well-Capitalized	1,269,357		1,220,113
Total risk-based capital, Actual Amount	$ 2,310,455		$ 2,316,580
Total risk-based capital, Actual Ratio	11.83%		12.34%
Total risk-based capital, Capital Requirements, Minimum Amount	$ 1,562,285		$ 1,501,677
Total risk-based capital, Capital Requirements, Minimum Ratio	8.00%		8.00%
Total risk-based capital, Capital Requirements, Well Capitalized Amount	$ 1,952,857		$ 1,877,097
Total risk-based capital, Capital Requirements, Well Capitalized Ratio	10.00%		10.00%
Tier 1 capital, Actual Amount	$ 2,100,537		$ 2,114,224
Tier 1 capital, Actual Ratio	10.76%		11.26%
Tier 1 capital, Capital Requirements, Minimum Amount	$ 1,171,714		$ 1,126,258
Tier 1 capital, Capital Requirements, Minimum Ratio	6.00%		6.00%
Tier 1 capital, Capital Requirements, Well Capitalized Amount	$ 1,562,285		$ 1,501,677
Tier 1 capital, Capital Requirements, Well Capitalized Ratio	8.00%		8.00%
Tier 1 leverage capital ratio, Actual Amount	$ 2,100,537		$ 2,114,224
Tier 1 leverage capital ratio, Actual Ratio	7.97%		8.14%
Tier 1 leverage capital ratio, Capital Requirements, Minimum Amount	$ 1,054,035		$ 1,038,442
Tier 1 leverage capital ratio, Capital Requirements, Minimum Ratio	4.00%		4.00%
Tier 1 leverage capital ratio, Capital Requirements, Well Capitalized Amount	$ 1,317,543		$ 1,298,052
Tier 1 leverage capital ratio, Capital Requirements, Well Capitalized Ratio	5.00%		5.00%
Cash Pass-through Reserve, Federal Home Loan Bank	$ 89,000		$ 82,300
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		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Earnings for basic and diluted earnings per common share:
Net income	$ 81,682	$ 61,579	$ 161,907	$ 121,050
Less: Preferred stock dividends	1,969	2,024	3,916	4,048
Undistributed Earnings, Basic	79,713	59,555	157,991	117,002
Net income available to common shareholders	79,713	59,555	157,991	117,002
Less: Earnings applicable to participating securities	224	70	418	176
Less: Earnings applicable to participating securities	224	70	418	176
Earnings applicable to common shareholders	79,489	59,485	157,573	116,826
Earnings applicable to common shareholders	$ 79,489	$ 59,485	$ 157,573	$ 116,826
Shares:
Weighted average common shares outstanding - basic (in shares)	91,893	92,092	91,913	91,989
Effect of dilutive securities:
Stock options and restricted stock (in shares)	274	397	317	475
Warrants (in shares)	6	6	6	6
Weighted-average common shares outstanding - diluted (in shares)	92,173	92,495	92,236	92,470
Earnings per common share:
Basic (in dollars per share)	$ 0.87	$ 0.65	$ 1.71	$ 1.27
Diluted (in dollars per share)	$ 0.86	$ 0.64	$ 1.71	$ 1.26

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		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
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	53	79	61	60

Derivative Financial Instrume81

Derivative Financial Instruments (Schedule fair value of derivative instruments) (Detail) - USD ($)		Jun. 30, 2018	Dec. 31, 2017
Derivatives, Fair Value [Line Items]
Derivative instrument assets, Gross Amount		$ 17,600,000	$ 8,992,000
Asset Derivatives, Fair Value, Less: Cash collateral posted		34,500,000
Derivative Asset		80,000	43,000
Liability Derivatives, Fair Value, Gross Liability		806,000	2,387,000
Liability Derivatives, Fair Value, Less: Cash collateral posted		101,100,000
Derivative liability		77,000	142,000
CME [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset		0
Subject to and not subject to Master Netting Agreements [Member]
Derivatives, Fair Value [Line Items]
Asset Derivatives, Notional Amounts		4,679,437,000	4,613,183,000
Derivative Asset, Fair Value, Gross Asset Including Not Subject to Master Netting Arrangement		25,294,000	32,515,000
Asset Derivatives, Fair Value, Less: Legally enforceable master netting agreements		729,000	2,245,000
Asset Derivatives, Fair Value, Less: Cash collateral posted		16,791,000	6,704,000
Derivative Asset		7,774,000	23,566,000
Liability Derivatives, Notional Amount		3,420,825,000	3,056,079,000
Derivative Liability, Fair Value, Gross Liability Including Not Subject to Master Netting Arrangement		72,137,000	28,423,000
Liability Derivatives, Fair Value, Less: Legally enforceable master netting agreements		729,000	2,245,000
Liability Derivatives, Fair Value, Less: Cash collateral posted		0	0
Derivative liability		71,408,000	26,178,000
Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative instrument assets, Gross Amount		4,685,000	2,770,000
Asset Derivatives, Fair Value, Less: Legally enforceable master netting agreements		0	91,000
Asset Derivatives, Fair Value, Less: Cash collateral posted		4,685,000	2,679,000
Derivative Asset		0	0
Liability Derivatives, Fair Value, Gross Liability		0	0
Liability Derivatives, Fair Value, Less: Legally enforceable master netting agreements		0	0
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]	325,000,000	325,000,000
Derivative instrument assets, Gross Amount	[1]	4,685,000	2,770,000
Liability Derivatives, Notional Amount	[1]	0	0
Liability Derivatives, Fair Value, Gross Liability	[1]	0	0
Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative instrument assets, Gross Amount		12,915,000	6,222,000
Asset Derivatives, Fair Value, Less: Legally enforceable master netting agreements		729,000	2,154,000
Asset Derivatives, Fair Value, Less: Cash collateral posted		12,106,000	4,025,000
Derivative Asset		80,000	43,000
Liability Derivatives, Fair Value, Gross Liability		806,000	2,387,000
Liability Derivatives, Fair Value, Less: Legally enforceable master netting agreements		729,000	2,245,000
Liability Derivatives, Fair Value, Less: Cash collateral posted		0	0
Derivative liability		77,000	142,000
Not Designated as Hedging Instrument [Member] | CME [Member]
Derivatives, Fair Value [Line Items]
Asset Derivatives, Notional Amounts	[1]	2,500,000,000	1,900,000,000
Liability Derivatives, Notional Amount	[1]	171,000,000	595,000,000
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]	3,523,220,000	2,791,760,000
Derivative instrument assets, Gross Amount	[1]	12,286,000	5,977,000
Liability Derivatives, Notional Amount	[1]	198,836,000	721,048,000
Liability Derivatives, Fair Value, Gross Liability	[1]	321,000	1,968,000
Not Designated as Hedging Instrument [Member] | Derivatives Subject to Master Netting Arrangement or Similar Arrangement [Member] | Mortgage Banking Derivatives [Member] | RPA-Out [Member]
Derivatives, Fair Value [Line Items]
Asset Derivatives, Notional Amounts		41,718,000	28,497,000
Derivative instrument assets, Gross Amount		441,000	421,000
Not Designated as Hedging Instrument [Member] | Derivatives Subject to Master Netting Arrangement or Similar Arrangement [Member] | Mortgage Banking Derivatives [Member] | RPA-In [Member]
Derivatives, Fair Value [Line Items]
Liability Derivatives, Notional Amount		32,053,000	39,230,000
Liability Derivatives, Fair Value, Gross Liability		199,000	110,000
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]	29,571,000	7,914,000
Derivative instrument assets, Gross Amount	[1]	629,000	258,000
Liability Derivatives, Notional Amount	[1]	38,224,000	30,328,000
Liability Derivatives, Fair Value, Gross Liability	[1]	485,000	419,000
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		4,354,437,000	4,288,183,000
Asset Derivatives, Fair Value, Positions not subject to master netting agreement		20,609,000	29,745,000
Liability Derivatives, Notional Amount		3,420,825,000	3,056,079,000
Liability Derivatives, Fair Value, Positions not subject to master netting agreement		72,137,000	28,423,000
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		666,149,000	1,366,299,000
Asset Derivatives, Fair Value, Positions not subject to master netting agreement		6,987,000	23,009,000
Liability Derivatives, Notional Amount		3,055,950,000	2,146,518,000
Liability Derivatives, Fair Value, Positions not subject to master netting agreement		71,057,000	25,631,000
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		85,164,000	93,713,000
Asset Derivatives, Fair Value, Positions not subject to master netting agreement		26,000	80,000
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		95,340,000	116,882,000
Liability Derivatives, Fair Value, Positions not subject to master netting agreement		58,000	111,000
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		8,615,000	0
Asset Derivatives, Fair Value, Positions not subject to master netting agreement		240,000	0
Liability Derivatives, Notional Amount		422,000	2,073,000
Liability Derivatives, Fair Value, Positions not subject to master netting agreement		17,000	$ 184,000
Loan Origination Commitments [Member]
Derivatives, Fair Value [Line Items]
Other Commitment		41,000,000
Interest Rate Lock Commitments [Member]
Derivatives, Fair Value [Line Items]
Other Commitment		$ 14,900,000
[1]	o report derivative positions subject to a legally enforceable master netting agreement on a net basis, net of cash collateral. Refer to the Offsetting Derivatives section of this footnote for additional information.

Derivative Financial Instrume82

Derivative Financial Instruments (Schedule of the changes in the fair value of non-hedge accounting derivatives) (Detail) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2017	Mar. 31, 2017	Jun. 30, 2018	Jun. 30, 2017
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) on Fair Value Hedges Recognized in Earnings	$ 3,848		$ 1,243		$ 7,114	$ 342
Interest Rate Derivatives [Member] | Operating Expense [Member] | Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) on Fair Value Hedges Recognized in Earnings		$ 1,668		$ 1,986	3,491	4,025
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	1,958		1,361		5,749	2,895
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	85		53		95	106
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	(134)		374		(69)	(1,667)
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	$ 1,939		$ (545)		$ 1,339	$ (992)

Derivative Financial Instrume83

Derivative Financial Instruments (AOCI Related to Cash Flow Hedges) (Narrative) (Detail) - Cash Flow Hedging [Member] $ in Thousands	6 Months Ended
	Jun. 30, 2018USD ($)
Derivative Instruments, Gain (Loss) [Line Items]
Estimate of amount to be reclassified from AOCL	$ (5,000)
Remaining unamortized gain (loss) on termination of cash flow hedges	(11,700)
Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Estimate of amount to be reclassified from AOCL	$ (109)

Derivative Financial Instrume84

Derivative Financial Instruments (Offsetting Derivatives) (Detail) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2017	Mar. 31, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Derivative [Line Items]
Gain (Loss) on Fair Value Hedges Recognized in Earnings	$ 3,848		$ 1,243		$ 7,114	$ 342
Derivative instrument assets, Gross Amount	17,600				17,600		$ 8,992
Derivative instrument asset, Amount Offset	34,500				34,500
Derivative Asset	80				80		43
Liability Derivatives, Fair Value, Gross Liability	806				806		2,387
Derivative Liability, Collateral, Right to Reclaim Cash, Offset	(101,100)				(101,100)
Derivative liability	77				77		142
Hedge Accounting Positions [Member]
Derivative [Line Items]
Derivative instrument assets, Gross Amount	4,685				4,685		2,770
Derivative instrument asset, Amount Offset, Total	0				0		(91)
Derivative instrument asset, Amount Offset	4,685				4,685		2,679
Derivative Asset	0				0		0
Liability Derivatives, Fair Value, Gross Liability	0				0		0
Derivative instrument liability, Amount Offset, Total	0				0		0
Derivative Liability, Collateral, Right to Reclaim Cash, Offset	0				0		0
Derivative liability	0				0		0
Non-Hedged Accounting Positions [Member]
Derivative [Line Items]
Derivative instrument assets, Gross Amount	12,915				12,915		6,222
Derivative instrument asset, Amount Offset, Total	(729)				(729)		(2,154)
Derivative instrument asset, Amount Offset	12,106				12,106		4,025
Derivative Asset	80				80		43
Liability Derivatives, Fair Value, Gross Liability	806				806		2,387
Derivative instrument liability, Amount Offset, Total	(729)				(729)		(2,245)
Derivative Liability, Collateral, Right to Reclaim Cash, Offset	0				0		0
Derivative liability	77				77		142
Subject to and not subject to Master Netting Agreements [Member]
Derivative [Line Items]
Derivative instrument asset, Amount Offset, Total	(729)				(729)		(2,245)
Derivative instrument asset, Amount Offset	16,791				16,791		6,704
Derivative Asset	7,774				7,774		23,566
Derivative instrument liability, Amount Offset, Total	(729)				(729)		(2,245)
Derivative Liability, Collateral, Right to Reclaim Cash, Offset	0				0		0
Derivative liability	71,408				71,408		$ 26,178
Interest Rate Derivatives [Member] | Operating Expense [Member] | Hedge Accounting Positions [Member]
Derivative [Line Items]
Gain (Loss) on Fair Value Hedges Recognized in Earnings		$ 1,668		$ 1,986	3,491	4,025
Interest Rate Derivatives [Member] | Operating Expense [Member] | Non-Hedged Accounting Positions [Member]
Derivative [Line Items]
Gain (Loss) on Fair Value Hedges Recognized in Earnings	$ 1,958		$ 1,361		$ 5,749	$ 2,895

Derivative Financial Instrume85

Derivative Financial Instruments (Counterparty Credit Risk Narrative) (Detail) $ in Millions	Jun. 30, 2018USD ($)
Derivative [Line Items]
Derivative, Collateral, Right to Reclaim Cash	$ (66.6)
Derivative instrument asset, Amount Offset	34.5
Derivative Liability, Collateral, Right to Reclaim Cash, Offset	(101.1)
Credit Derivative, Maximum Exposure, Undiscounted	7
Valuation, Market Approach [Member]
Derivative [Line Items]
Credit Derivative, Maximum Exposure, Undiscounted	$ 30.2

Fair Value Measurements (Narrat

Fair Value Measurements (Narrative) (Detail) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total credit-related financial instruments with off-balance sheet risk	$ 6,180,627	$ 5,806,789
Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Book value of other real estate owned (OREO) and repossessed assets	6,000
Rabbi Trust [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other assets	2,000
Alternative investments [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total credit-related financial instruments with off-balance sheet risk	300
Alternative investments [Member] | Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other assets	$ 2,500

Fair Value Measurements (Fair V

Fair Value Measurements (Fair Value Assets And Liabilities Measured On Recurring and Nonrecurring Basis) (Detail) - USD ($) $ in Thousands		Jun. 30, 2018	Dec. 31, 2017
Financial assets held at fair value:
Debt Securities, Available-for-sale		$ 2,780,581	$ 2,638,037
Investment securities available-for-sale, at fair value		2,780,581	2,638,037
Derivative Asset		80	43
Loans Held-for-sale, Fair Value Disclosure		18,645	20,888
Financial liabilities held at fair value:
Derivative liability		77	142
US Treasury Bill Securities [Member]
Financial assets held at fair value:
Debt Securities, Available-for-sale		2,491	1,247
Agency CMO [Member]
Financial assets held at fair value:
Debt Securities, Available-for-sale		265,253	306,333
Agency MBS [Member]
Financial assets held at fair value:
Debt Securities, Available-for-sale		1,311,841	1,107,841
Agency CMBS [Member]
Financial assets held at fair value:
Debt Securities, Available-for-sale		582,676	588,026
Non-agency CMBS [Member]
Financial assets held at fair value:
Debt Securities, Available-for-sale		374,556	361,067
CLO [Member]
Financial assets held at fair value:
Debt Securities, Available-for-sale		188,066	209,851
Single issuer trust preferred securities [Member]
Financial assets held at fair value:
Debt Securities, Available-for-sale		0	7,050
Corporate debt securities [Member]
Financial assets held at fair value:
Debt Securities, Available-for-sale		55,698	56,622
Fair Value, Measurements, Recurring [Member]
Financial assets held at fair value:
Debt Securities, Available-for-sale		2,780,581
Investment securities available-for-sale, at fair value			2,638,037
Alternative Investment		4,334	3,495
Total financial assets held at fair value		2,833,580	2,699,736
Financial liabilities held at fair value:
Derivative liability	[1]	72,137	28,423
Fair Value, Measurements, Recurring [Member] | Quoted Prices in Active Markets For Identical Assets (Level 1) [Member]
Financial assets held at fair value:
Debt Securities, Available-for-sale		2,491
Investment securities available-for-sale, at fair value			1,247
Alternative Investment		2,439	0
Total financial assets held at fair value		10,525	6,306
Financial liabilities held at fair value:
Derivative liability	[1]	485	587
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member]
Financial assets held at fair value:
Debt Securities, Available-for-sale		2,778,090
Investment securities available-for-sale, at fair value			2,636,790
Alternative Investment		0	0
Total financial assets held at fair value		2,821,160	2,689,935
Financial liabilities held at fair value:
Derivative liability	[1]	71,652	27,836
Fair Value, Measurements, Recurring [Member] | Fair Value Measured at Net Asset Value Per Share [Member]
Financial assets held at fair value:
Investment securities available-for-sale, at fair value			0
Alternative Investment		1,895	3,495
Total financial assets held at fair value		1,895	3,495
Financial liabilities held at fair value:
Derivative liability			0
Fair Value, Measurements, Recurring [Member] | Derivative instruments [Member]
Financial assets held at fair value:
Derivative Asset	[1]	25,294	32,515
Fair Value, Measurements, Recurring [Member] | Derivative instruments [Member] | Quoted Prices in Active Markets For Identical Assets (Level 1) [Member]
Financial assets held at fair value:
Derivative Asset	[1]	869	258
Fair Value, Measurements, Recurring [Member] | Derivative instruments [Member] | Significant Other Observable Inputs (Level 2) [Member]
Financial assets held at fair value:
Derivative Asset	[1]	24,425	32,257
Fair Value, Measurements, Recurring [Member] | Derivative instruments [Member] | Fair Value Measured at Net Asset Value Per Share [Member]
Financial assets held at fair value:
Derivative Asset			0
Fair Value, Measurements, Recurring [Member] | Investments Held In Rabbi Trust [Member]
Financial assets held at fair value:
Other assets		4,726	4,801
Fair Value, Measurements, Recurring [Member] | Investments Held In Rabbi Trust [Member] | Quoted Prices in Active Markets For Identical Assets (Level 1) [Member]
Financial assets held at fair value:
Other assets		4,726	4,801
Fair Value, Measurements, Recurring [Member] | Investments Held In Rabbi Trust [Member] | Fair Value Measured at Net Asset Value Per Share [Member]
Financial assets held at fair value:
Other assets			0
Fair Value, Measurements, Recurring [Member] | Loan Origination Commitments [Member]
Financial assets held at fair value:
Loans Held-for-sale, Fair Value Disclosure		18,645	20,888
Fair Value, Measurements, Recurring [Member] | Loan Origination Commitments [Member] | Quoted Prices in Active Markets For Identical Assets (Level 1) [Member]
Financial assets held at fair value:
Loans Held-for-sale, Fair Value Disclosure		0	0
Fair Value, Measurements, Recurring [Member] | Loan Origination Commitments [Member] | Significant Other Observable Inputs (Level 2) [Member]
Financial assets held at fair value:
Loans Held-for-sale, Fair Value Disclosure		18,645	20,888
Fair Value, Measurements, Recurring [Member] | Loan Origination Commitments [Member] | Fair Value Measured at Net Asset Value Per Share [Member]
Financial assets held at fair value:
Loans Held-for-sale, Fair Value Disclosure		0
Fair Value, Measurements, Recurring [Member] | US Treasury Bill Securities [Member]
Financial assets held at fair value:
Debt Securities, Available-for-sale		2,491
Investment securities available-for-sale, at fair value			1,247
Fair Value, Measurements, Recurring [Member] | US Treasury Bill Securities [Member] | Quoted Prices in Active Markets For Identical Assets (Level 1) [Member]
Financial assets held at fair value:
Debt Securities, Available-for-sale		2,491
Investment securities available-for-sale, at fair value			1,247
Fair Value, Measurements, Recurring [Member] | US Treasury Bill Securities [Member] | Fair Value Measured at Net Asset Value Per Share [Member]
Financial assets held at fair value:
Investment securities available-for-sale, at fair value			0
Fair Value, Measurements, Recurring [Member] | Agency CMO [Member]
Financial assets held at fair value:
Debt Securities, Available-for-sale		265,253
Investment securities available-for-sale, at fair value			306,333
Fair Value, Measurements, Recurring [Member] | Agency CMO [Member] | Significant Other Observable Inputs (Level 2) [Member]
Financial assets held at fair value:
Debt Securities, Available-for-sale		265,253
Investment securities available-for-sale, at fair value			306,333
Fair Value, Measurements, Recurring [Member] | Agency CMO [Member] | Fair Value Measured at Net Asset Value Per Share [Member]
Financial assets held at fair value:
Investment securities available-for-sale, at fair value			0
Fair Value, Measurements, Recurring [Member] | Agency MBS [Member]
Financial assets held at fair value:
Debt Securities, Available-for-sale		1,311,841
Investment securities available-for-sale, at fair value			1,107,841
Fair Value, Measurements, Recurring [Member] | Agency MBS [Member] | Significant Other Observable Inputs (Level 2) [Member]
Financial assets held at fair value:
Debt Securities, Available-for-sale		1,311,841
Investment securities available-for-sale, at fair value			1,107,841
Fair Value, Measurements, Recurring [Member] | Agency MBS [Member] | Fair Value Measured at Net Asset Value Per Share [Member]
Financial assets held at fair value:
Investment securities available-for-sale, at fair value			0
Fair Value, Measurements, Recurring [Member] | Agency CMBS [Member]
Financial assets held at fair value:
Debt Securities, Available-for-sale		582,676
Investment securities available-for-sale, at fair value			588,026
Fair Value, Measurements, Recurring [Member] | Agency CMBS [Member] | Quoted Prices in Active Markets For Identical Assets (Level 1) [Member]
Financial assets held at fair value:
Debt Securities, Available-for-sale		0
Investment securities available-for-sale, at fair value			0
Fair Value, Measurements, Recurring [Member] | Agency CMBS [Member] | Significant Other Observable Inputs (Level 2) [Member]
Financial assets held at fair value:
Debt Securities, Available-for-sale		582,676
Investment securities available-for-sale, at fair value			588,026
Fair Value, Measurements, Recurring [Member] | Agency CMBS [Member] | Significant Unobservable Inputs (Level 3) [Member]
Financial assets held at fair value:
Debt Securities, Available-for-sale		0
Investment securities available-for-sale, at fair value			0
Fair Value, Measurements, Recurring [Member] | Agency CMBS [Member] | Fair Value Measured at Net Asset Value Per Share [Member]
Financial assets held at fair value:
Debt Securities, Available-for-sale		0
Investment securities available-for-sale, at fair value			0
Fair Value, Measurements, Recurring [Member] | Non-agency CMBS [Member]
Financial assets held at fair value:
Debt Securities, Available-for-sale		374,556
Investment securities available-for-sale, at fair value			361,067
Fair Value, Measurements, Recurring [Member] | Non-agency CMBS [Member] | Quoted Prices in Active Markets For Identical Assets (Level 1) [Member]
Financial assets held at fair value:
Debt Securities, Available-for-sale		0
Investment securities available-for-sale, at fair value			0
Fair Value, Measurements, Recurring [Member] | Non-agency CMBS [Member] | Significant Other Observable Inputs (Level 2) [Member]
Financial assets held at fair value:
Debt Securities, Available-for-sale		374,556
Investment securities available-for-sale, at fair value			361,067
Fair Value, Measurements, Recurring [Member] | Non-agency CMBS [Member] | Significant Unobservable Inputs (Level 3) [Member]
Financial assets held at fair value:
Debt Securities, Available-for-sale		0
Investment securities available-for-sale, at fair value			0
Fair Value, Measurements, Recurring [Member] | Non-agency CMBS [Member] | Fair Value Measured at Net Asset Value Per Share [Member]
Financial assets held at fair value:
Debt Securities, Available-for-sale		0
Investment securities available-for-sale, at fair value			0
Fair Value, Measurements, Recurring [Member] | CLO [Member]
Financial assets held at fair value:
Debt Securities, Available-for-sale		188,066
Investment securities available-for-sale, at fair value			209,851
Fair Value, Measurements, Recurring [Member] | CLO [Member] | Significant Other Observable Inputs (Level 2) [Member]
Financial assets held at fair value:
Debt Securities, Available-for-sale		188,066
Investment securities available-for-sale, at fair value			209,851
Fair Value, Measurements, Recurring [Member] | CLO [Member] | Fair Value Measured at Net Asset Value Per Share [Member]
Financial assets held at fair value:
Investment securities available-for-sale, at fair value			0
Fair Value, Measurements, Recurring [Member] | Single issuer trust preferred securities [Member]
Financial assets held at fair value:
Investment securities available-for-sale, at fair value			7,050
Fair Value, Measurements, Recurring [Member] | Single issuer trust preferred securities [Member] | Significant Other Observable Inputs (Level 2) [Member]
Financial assets held at fair value:
Investment securities available-for-sale, at fair value			7,050
Fair Value, Measurements, Recurring [Member] | Single issuer trust preferred securities [Member] | Fair Value Measured at Net Asset Value Per Share [Member]
Financial assets held at fair value:
Investment securities available-for-sale, at fair value			0
Fair Value, Measurements, Recurring [Member] | Corporate debt securities [Member]
Financial assets held at fair value:
Debt Securities, Available-for-sale		55,698
Investment securities available-for-sale, at fair value			56,622
Fair Value, Measurements, Recurring [Member] | Corporate debt securities [Member] | Significant Other Observable Inputs (Level 2) [Member]
Financial assets held at fair value:
Debt Securities, Available-for-sale		$ 55,698
Investment securities available-for-sale, at fair value			56,622
Fair Value, Measurements, Recurring [Member] | Corporate debt securities [Member] | Fair Value Measured at Net Asset Value Per Share [Member]
Financial assets held at fair value:
Investment securities available-for-sale, at fair value			$ 0
[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 Fair Va

Fair Value Measurements Fair Value Option, Disclosures (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Fair Value, Option, Quantitative Disclosures [Line Items]
Loans Held-for-sale, Fair Value Disclosure	$ 18,645	$ 20,888
Fair Value, Option, Loans Held as Assets, Aggregate Difference	411	542
loans held for sale [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Loans and Leases Receivable, Gross, Consumer, Real Estate	$ 18,234	$ 20,346

Fair Value Measurements (Schedu

Fair Value Measurements (Schedule Of Valuation Methodology And Unobservable Inputs) (Detail) - Significant Unobservable Inputs (Level 3) [Member] - Fair Value, Measurements, Nonrecurring [Member] $ in Thousands	Jun. 30, 2018USD ($)
Impaired Loans and Leases [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Collateral dependent impaired loans and leases	$ 15,414
Other Real Estate Owned [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
OREO	$ 467
Measurement Input, Discount Rate [Member] | Impaired Loans and Leases [Member] | Valuation, Market Approach [Member] | Minimum [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Debt Instrument, Measurement Input	0
Measurement Input, Discount Rate [Member] | Impaired Loans and Leases [Member] | Valuation, Market Approach [Member] | Maximum [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Debt Instrument, Measurement Input	0.15
Measurement Input, Discount Rate [Member] | Impaired Loans and Leases [Member] | Valuation, Cost Approach [Member] | Minimum [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Debt Instrument, Measurement Input	0
Measurement Input, Discount Rate [Member] | Impaired Loans and Leases [Member] | Valuation, Cost Approach [Member] | Maximum [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Debt Instrument, Measurement Input	0.08
Measurement Input, Discount Rate [Member] | Other Real Estate Owned [Member] | Valuation, Market Approach [Member] | Minimum [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Other Real Estate Owned, Measurement Input	0
Measurement Input, Discount Rate [Member] | Other Real Estate Owned [Member] | Valuation, Market Approach [Member] | Maximum [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Other Real Estate Owned, Measurement Input	0.20
Measurement Input, Discount Rate [Member] | Other Real Estate Owned [Member] | Valuation, Cost Approach [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Other Real Estate Owned, Measurement Input	0.08

Fair Value Measurements (Summar

Fair Value Measurements (Summary Of Estimated Fair Values Of Significant Financial Instruments) (Detail) - USD ($) $ in Thousands		Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans held for sale		$ 18,645		$ 20,888
Mortgage servicing assets, Carrying Amount		23,341	$ 24,403	25,139	$ 24,708	$ 24,336	$ 24,466
Fair Value, Measurements, Nonrecurring [Member] | Reported Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans and leases, net		17,818,674		17,323,864
Securities sold under agreements to repurchase and other borrowings		862,568		643,269
FHLB advances	[1]	1,576,956		1,677,105
Long-term debt	[1]	225,894		225,767
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		18,503,653		18,525,321
Fair Value, Measurements, Nonrecurring [Member] | Reported Value Measurement [Member] | Time Deposits [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Deposits		2,839,703		2,468,408
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		4,356,219		4,487,392
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		23,341		25,139
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]
Securities sold under agreements to repurchase and other borrowings		862,371		644,084
FHLB advances	[1]	1,576,797		1,678,070
Long-term debt	[1]	230,223		234,359
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		17,642,617		17,211,619
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		18,503,653		18,525,321
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		2,811,645		2,455,245
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		4,225,983		4,456,350
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		$ 49,182		$ 45,309
[1]	djustments to the carrying amount of long-term debt for unamortized discount and debt issuance cost on senior fixed-rate notes are not included for determination of fair value, see Note 8: Borrowings

Retirement Benefit Plans (Detai

Retirement Benefit Plans (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 0	$ 13	$ 0	$ 25
Interest cost on benefit obligations	1,935	1,844	3,720	3,657
Expected return on plan assets	(3,180)	(3,075)	(6,360)	(6,148)
Amortization of prior service cost	0	0	0	0
Recognized net loss	1,160	1,515	2,320	2,932
Net periodic benefit cost	(85)	297	(320)	466
Supplemental Employee Retirement Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	0	0	0	0
Interest cost on benefit obligations	(21)	93	166	185
Expected return on plan assets	0	0	0	0
Amortization of prior service cost	0	0	0	0
Recognized net loss	333	212	458	425
Net periodic benefit cost	312	305	624	610
Other Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	0	0	0	0
Interest cost on benefit obligations	19	25	39	50
Expected return on plan assets	0	0	0	0
Amortization of prior service cost	0	0	0	0
Recognized net loss	0	7	0	15
Net periodic benefit cost	$ 19	$ 32	$ 39	$ 65

Share-Based Plans (Narrative) (

Share-Based Plans (Narrative) (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Allocated Share-based Compensation Expense	$ 2,500	$ 2,700	$ 5,900	$ 6,000
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized stock compensation expense	$ 18,400		$ 18,400
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		100,000
Time Based Restricted Stock Awards [Member] | Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period (in years)			1 year
Time Based Restricted Stock Awards [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period (in years)			3 years
Performance-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)	492,792		492,792		673,039
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)	458,904		458,904
Incentive Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of options outstanding (in shares)	33,888		33,888

Share-Based Plans (Summary of R

Share-Based Plans (Summary of Restricted Stock and Stock Option Activity) (Detail) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Allocated Share-based Compensation Expense		$ 2,500	$ 2,700	$ 5,900	$ 6,000
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)				207,800
Restricted stock, Granted (in shares)				122,948
Restricted stock, Vested restricted stock awards (in shares)	[1]			87,408
Restricted stock, Forfeited (in shares)				3,296
Restricted stock, Outstanding at end of period (in shares)		240,044		240,044
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)				$ 43.16
Restricted stock, Granted (in dollars per share)				56.87
Restricted stock, Vested restricted stock awards (in dollars per share)	[1]			43.71
Restricted stock, Forfeited (in dollars per share)				52.74
Restricted stock, at end of period, Weighted-average Grant Date Fair Value (in dollars per share)		$ 49.85		$ 49.85
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)				78,916
Restricted stock, Granted (in shares)				75,707
Restricted stock, Vested restricted stock awards (in shares)	[1]			38,426
Restricted stock, Forfeited (in shares)				6,192
Restricted stock, Outstanding at end of period (in shares)		110,005		110,005
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)				$ 45.35
Restricted stock, Granted (in dollars per share)				55.82
Restricted stock, Vested restricted stock awards (in dollars per share)	[1]			45.26
Restricted stock, Forfeited (in dollars per share)				50.64
Restricted stock, at end of period, Weighted-average Grant Date Fair Value (in dollars per share)		$ 52.29		$ 52.29
Employee Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Options outstanding, at beginning of period, Number of Shares				673,039
Options granted, Number of Shares				0
Exercised options, Number of Shares				180,247
Options forfeited, Number of Shares				0
Options outstanding, at end of period, Number of Shares		492,792		492,792
Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Options, at beginning of period, Weighted-average Exercise Price (in dollars per share)				$ 18.75
Options granted, Weighted-Average Exercise Price (in dollars per share)				0
Exercised options, Weighted-Average Exercise Price (in dollars per share)				11.71
Options forfeited, Weighted-Average Exercise Price (in dollars per share)				0
Options, at end of period, Weighted-average Exercise Price (in dollars per share)		$ 21.33		$ 21.33
[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		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Segment Reporting Information [Line Items]
Total Assets	$ 27,036,737		$ 27,036,737		$ 26,487,645
Net interest income (expense)	225,010	$ 197,787	439,178	$ 390,451
Provision for Loan and Lease Losses	10,500	7,250	21,500	17,750
Net interest income after provision for loan and lease losses	214,510	190,537	417,678	372,701
Noninterest Income	68,374	64,551	137,121	127,593
Total non-interest expense	180,459	164,419	352,074	328,203
Income (loss) before income tax expense	102,425	90,669	202,725	172,091
Income tax expense	20,743	29,090	40,818	51,041
Net income	81,682	61,579	161,907	121,050
Operating Segments [Member] | Commercial Banking [Member]
Segment Reporting Information [Line Items]
Total Assets	9,972,737		9,972,737		9,350,028
Net interest income (expense)	88,459	78,946	173,110	157,193
Provision for Loan and Lease Losses	10,915	10,692	18,093	17,489
Net interest income after provision for loan and lease losses	77,544	68,254	155,017	139,704
Noninterest Income	15,041	12,532	30,357	25,956
Total non-interest expense	42,979	37,304	84,224	75,428
Income (loss) before income tax expense	49,606	43,482	101,150	90,232
Income tax expense	12,203	14,158	24,883	26,762
Net income	37,403	29,324	76,267	63,470
Operating Segments [Member] | HSA Bank [Member]
Segment Reporting Information [Line Items]
Total Assets	73,914		73,914		76,308
Net interest income (expense)	35,265	25,574	68,189	49,626
Provision for Loan and Lease Losses	0	0	0	0
Net interest income after provision for loan and lease losses	35,265	25,574	68,189	49,626
Noninterest Income	22,882	19,750	45,551	39,021
Total non-interest expense	31,220	28,750	62,735	56,989
Income (loss) before income tax expense	26,927	16,574	51,005	31,658
Income tax expense	7,001	5,323	13,261	9,389
Net income	19,926	11,251	37,744	22,269
Operating Segments [Member] | Community Banking [Member]
Segment Reporting Information [Line Items]
Total Assets	8,793,382		8,793,382		8,909,671
Net interest income (expense)	101,902	95,902	200,830	189,492
Provision for Loan and Lease Losses	(415)	(3,442)	3,407	261
Net interest income after provision for loan and lease losses	102,317	99,344	197,423	189,231
Noninterest Income	26,378	28,058	51,573	53,437
Total non-interest expense	95,197	94,322	192,026	189,501
Income (loss) before income tax expense	33,498	33,080	56,970	53,167
Income tax expense	6,666	10,353	11,337	15,769
Net income	26,832	22,727	45,633	37,398
Corporate, Non-Segment [Member]
Segment Reporting Information [Line Items]
Total Assets	8,196,704		8,196,704		$ 8,151,638
Net interest income (expense)	(616)	(2,635)	(2,951)	(5,860)
Provision for Loan and Lease Losses	0	0	0	0
Net interest income after provision for loan and lease losses	(616)	(2,635)	(2,951)	(5,860)
Noninterest Income	4,073	4,211	9,640	9,179
Total non-interest expense	11,063	4,043	13,089	6,285
Income (loss) before income tax expense	(7,606)	(2,467)	(6,400)	(2,966)
Income tax expense	(5,127)	(744)	(8,663)	(879)
Net income	$ (2,479)	$ (1,723)	$ 2,263	$ (2,087)

Segment Reporting Segment Repor

Segment Reporting Segment Reporting Narrative (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018USD ($)	Jun. 30, 2017USD ($)	Jun. 30, 2018USD ($)Segment	Jun. 30, 2017USD ($)
Segment Reporting Information [Line Items]
Number of Reportable Segments | Segment			3
Deposit insurance	$ 13,687	$ 6,625	$ 20,404	$ 13,357
Corporate, Non-Segment [Member]
Segment Reporting Information [Line Items]
Deposit insurance			$ 7,200

Revenue from Contracts with C96

Revenue from Contracts with Customers Revenue from Contracts with Customers (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	$ 50,831	$ 46,948	$ 100,502	$ 92,238
Noninterest Income	68,374	64,551	137,121	127,593
Deposit service fees [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	40,859	38,192	81,310	75,198
Wealth and investment services [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	8,456	7,877	16,326	15,150
Other non interest income [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	1,516	879	2,866	1,890
Non-interest income within the scope of other GAAP topics [Member]
Disaggregation of Revenue [Line Items]
Noninterest Income	17,543	17,603	36,619	35,355
Operating Segments [Member] | Commercial Banking [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	5,767	5,460	11,528	10,710
Noninterest Income	15,041	12,532	30,357	25,956
Operating Segments [Member] | Commercial Banking [Member] | Deposit service fees [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	3,180	3,015	6,402	5,893
Operating Segments [Member] | Commercial Banking [Member] | Wealth and investment services [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	2,587	2,445	5,126	4,817
Operating Segments [Member] | Commercial Banking [Member] | Other non interest income [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	0	0	0	0
Operating Segments [Member] | Commercial Banking [Member] | Non-interest income within the scope of other GAAP topics [Member]
Disaggregation of Revenue [Line Items]
Noninterest Income	9,274	7,072	18,829	15,246
Operating Segments [Member] | Community Banking [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	22,181	21,685	43,322	42,348
Noninterest Income	26,378	28,058	51,573	53,437
Operating Segments [Member] | Community Banking [Member] | Deposit service fees [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	15,663	16,081	30,972	31,611
Operating Segments [Member] | Community Banking [Member] | Wealth and investment services [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	5,878	5,441	11,217	10,350
Operating Segments [Member] | Community Banking [Member] | Other non interest income [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	640	163	1,133	387
Operating Segments [Member] | Community Banking [Member] | Non-interest income within the scope of other GAAP topics [Member]
Disaggregation of Revenue [Line Items]
Noninterest Income	4,197	6,373	8,251	11,089
Operating Segments [Member] | HSA Bank [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	22,882	19,750	45,551	39,021
Noninterest Income	22,882	19,750	45,551	39,021
Operating Segments [Member] | HSA Bank [Member] | Deposit service fees [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	22,006	19,034	43,818	37,518
Operating Segments [Member] | HSA Bank [Member] | Wealth and investment services [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	0	0	0	0
Operating Segments [Member] | HSA Bank [Member] | Other non interest income [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	876	716	1,733	1,503
Operating Segments [Member] | HSA Bank [Member] | Non-interest income within the scope of other GAAP topics [Member]
Disaggregation of Revenue [Line Items]
Noninterest Income	0	0	0	0
Corporate, Non-Segment [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	1	53	101	159
Noninterest Income	4,073	4,211	9,640	9,179
Corporate, Non-Segment [Member] | Deposit service fees [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	10	62	118	176
Corporate, Non-Segment [Member] | Wealth and investment services [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	(9)	(9)	(17)	(17)
Corporate, Non-Segment [Member] | Other non interest income [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	0	0	0	0
Corporate, Non-Segment [Member] | Non-interest income within the scope of other GAAP topics [Member]
Disaggregation of Revenue [Line Items]
Noninterest Income	$ 4,072	$ 4,158	$ 9,539	$ 9,020

Commitments and Contingencies97

Commitments and Contingencies (Outstanding Financial Instruments Contract Amounts Represent Credit Risk) (Detail) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Loss Contingencies [Line Items]
Total credit-related financial instruments with off-balance sheet risk	$ 6,180,627	$ 5,806,789
Standby letter of credit [Member]
Loss Contingencies [Line Items]
Total credit-related financial instruments with off-balance sheet risk	206,506	195,902
Commercial letter of credit [Member]
Loss Contingencies [Line Items]
Total credit-related financial instruments with off-balance sheet risk	44,176	43,200
Commitments to extend credit [Member]
Loss Contingencies [Line Items]
Total credit-related financial instruments with off-balance sheet risk	$ 5,929,945	$ 5,567,687

(Reserve for Unfunded Commitmen

(Reserve for Unfunded Commitments) (Detail) - SEC Schedule, 12-09, Allowance, Credit Loss [Member] - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Beginning balance	$ 2,294	$ 2,655	$ 2,362	$ 2,287
Provision (benefit) charged to expense	302	(111)	234	257
Ending balance	$ 2,596	$ 2,544	$ 2,596	$ 2,544