Washington Trust Bancorp (WASH) 10-Q 5 Nov 18 2018 Q3 Quarterly report Financial data

DOCUMENT AND ENTITY INFORMATION

DOCUMENT AND ENTITY INFORMATION - shares	9 Months Ended
	Sep. 30, 2018	Oct. 31, 2018
Document and Entity Information [Abstract]
Entity Registrant Name	Washington Trust Bancorp Inc
Entity Central Index Key	737,468
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Document Type	10-Q
Document Period End Date	Sep. 30, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	Q3
Amendment Flag	false
Entity Common Stock, Shares Outstanding		17,294,570

CONSOLIDATED BALANCE SHEETS (Un

CONSOLIDATED BALANCE SHEETS (Unaudited) - USD ($) $ in Thousands		Sep. 30, 2018	Dec. 31, 2017
Assets:
Cash and due from banks		$ 72,934	$ 79,853
Short-term investments		2,917	3,070
Mortgage loans held for sale, at fair value		22,571	26,943
Securities:
Available for sale, at fair value		812,647	780,954
Held to maturity, at amortized cost		10,863	12,541
Total securities		823,510	793,495
Federal Home Loan Bank stock, at cost		44,525	40,517
Loans:
Total loans	[1]	3,556,203	3,374,071
Less allowance for loan losses		26,509	26,488
Net loans		3,529,694	3,347,583
Premises and equipment, net		28,195	28,333
Investment in bank-owned life insurance		79,891	73,267
Goodwill		63,909	63,909
Identifiable intangible assets, net		8,400	9,140
Other assets		94,126	63,740
Total assets		4,770,672	4,529,850
Liabilities:
Noninterest-bearing deposits		611,829	578,410
Interest-bearing deposits		2,802,519	2,664,297
Total deposits		3,414,348	3,242,707
Federal Home Loan Bank advances		828,392	791,356
Junior subordinated debentures		22,681	22,681
Other liabilities		77,342	59,822
Total liabilities		4,342,763	4,116,566
Commitments and contingencies (Note 18)
Shareholders' Equity:
Common stock		1,081	1,077
Paid-in capital		119,220	117,961
Retained earnings		346,685	317,756
Accumulated other comprehensive loss		(39,077)	(23,510)
Total shareholders' equity		427,909	413,284
Total liabilities and shareholders’ equity		$ 4,770,672	$ 4,529,850
[1]	Includes net unamortized loan origination costs of $4.8 million and $3.8 million, respectively, at September 30, 2018 and December 31, 2017 and net unamortized premiums on purchased loans of $746 thousand and $878 thousand, respectively, at September 30, 2018 and December 31, 2017.

CONSOLIDATED BALANCE SHEETS (_2

CONSOLIDATED BALANCE SHEETS (Unaudited) (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Statement of Financial Position [Abstract]
Securities held to maturity, fair value	$ 10,657	$ 12,721
Common stock, par value	$ 0.0625	$ 0.0625
Common stock, shares authorized	60,000,000	60,000,000
Common stock, shares issued	17,290,443	17,226,508
Common stock, shares outstanding	17,290,443	17,226,508

CONSOLIDATED STATEMENTS OF INCO

CONSOLIDATED STATEMENTS OF INCOME (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Interest income:
Interest and fees on loans	$ 38,877	$ 32,509	$ 110,556	$ 94,503
Taxable interest on securities	5,383	4,655	15,859	14,208
Nontaxable interest on securities	9	41	52	225
Dividends on Federal Home Loan Bank stock	634	467	1,700	1,293
Other interest income	261	197	723	457
Total interest and dividend income	45,164	37,869	128,890	110,686
Interest expense:
Deposits	6,546	3,835	16,222	10,928
Federal Home Loan Bank advances	4,937	3,816	13,627	10,669
Junior subordinated debentures	232	159	629	446
Other interest expense	0	0	0	1
Total interest expense	11,715	7,810	30,478	22,044
Net interest income	33,449	30,059	98,412	88,642
Provision for loan losses	350	1,300	750	2,400
Net interest income after provision for loan losses	33,099	28,759	97,662	86,242
Noninterest income:
Wealth management revenues	9,454	10,013	29,329	29,432
Mortgage banking revenues	2,624	3,036	8,403	8,295
Service charges on deposit accounts	885	942	2,651	2,726
Card interchange fees	983	894	2,791	2,598
Income from bank-owned life insurance	572	546	1,624	1,624
Loan related derivative income	278	1,452	1,087	2,744
Other income	419	400	1,066	1,180
Total noninterest income	15,215	17,283	46,951	48,599
Noninterest expense:
Salaries and employee benefits	17,283	17,362	52,359	51,697
Outsourced services	1,951	1,793	6,174	4,960
Net occupancy	2,013	1,928	5,945	5,662
Equipment	1,080	1,380	3,329	4,160
Legal, audit and professional fees	559	534	1,840	1,732
FDIC deposit insurance costs	410	308	1,236	1,258
Advertising and promotion	440	416	946	1,015
Amortization of intangibles	245	253	740	787
Change in fair value of contingent consideration	0	0	0	(310)
Other expenses	2,081	2,780	6,911	7,385
Total noninterest expense	26,062	26,754	79,480	78,346
Income before income taxes	22,252	19,288	65,133	56,495
Income tax expense	4,741	6,326	13,737	18,552
Net income	$ 17,511	$ 12,962	$ 51,396	$ 37,943
Weighted average common shares outstanding - basic	17,283	17,212	17,263	17,201
Weighted average common shares outstanding - diluted	17,382	17,318	17,392	17,320
Per share information:
Basic earnings per common share	$ 1.01	$ 0.75	$ 2.97	$ 2.20
Diluted earnings per common share	1.01	0.75	2.95	2.19
Cash dividends declared per share	$ 0.43	$ 0.39	$ 1.29	$ 1.15

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Statement of Comprehensive Income [Abstract]
Net income	$ 17,511	$ 12,962	$ 51,396	$ 37,943
Other comprehensive income (loss), net of tax:
Net change in fair value of securities available for sale	(4,531)	1,094	(18,057)	3,323
Net change in fair value of cash flow hedges	155	(13)	1,409	(364)
Net change in defined benefit plan obligations	361	217	1,081	427
Total other comprehensive income (loss), net of tax	(4,015)	1,298	(15,567)	3,386
Total comprehensive income	$ 13,496	$ 14,260	$ 35,829	$ 41,329

CONSOLIDATED STATEMENTS OF CHAN

CONSOLIDATED STATEMENTS OF CHANGES IN SHAREHOLDERS' EQUITY (Unaudited) - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]
Common Stock, Shares Outstanding, Beginning Balance at Dec. 31, 2016		17,171,000
Shareholders' Equity, Beginning Balance at Dec. 31, 2016	$ 390,804	$ 1,073	$ 115,123	$ 294,365	$ (19,757)
Net income	37,943			37,943
Total other comprehensive income (loss), net of tax	3,386				3,386
Cash dividends declared	(19,974)			(19,974)
Share-based compensation	1,872		1,872
Exercise of stock options and issuance of other compensation-related equity awards, shares		43,000
Exercise of stock options and issuance of other compensation-related equity awards, value	197	$ 3	194
Common Stock, Shares Outstanding, Ending Balance at Sep. 30, 2017		17,214,000
Shareholders' Equity, Ending Balance at Sep. 30, 2017	$ 414,228	$ 1,076	117,189	312,334	(16,371)
Common Stock, Shares Outstanding, Beginning Balance at Dec. 31, 2017	17,226,508	17,227,000
Shareholders' Equity, Beginning Balance at Dec. 31, 2017	$ 413,284	$ 1,077	117,961	317,756	(23,510)
Net income	51,396			51,396
Total other comprehensive income (loss), net of tax	(15,567)				(15,567)
Cash dividends declared	(22,467)			(22,467)
Share-based compensation	1,977		1,977
Exercise of stock options and issuance of other compensation-related equity awards, shares		63,000
Exercise of stock options and issuance of other compensation-related equity awards, value	$ (714)	$ 4	(718)
Common Stock, Shares Outstanding, Ending Balance at Sep. 30, 2018	17,290,443	17,290,000
Shareholders' Equity, Ending Balance at Sep. 30, 2018	$ 427,909	$ 1,081	$ 119,220	$ 346,685	$ (39,077)

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Cash flows from operating activities:
Net income	$ 51,396	$ 37,943
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for loan losses	750	2,400
Depreciation of premises and equipment	2,454	2,613
Net amortization of premium and discount	2,157	2,560
Amortization of intangibles	740	787
Goodwill impairment	0	150
Share-based compensation	1,977	1,872
Tax benefit from stock option exercises and other equity awards	454	414
Income from bank-owned life insurance	(1,624)	(1,624)
Net gains on loan sales and commissions on loans originated for others, including fair value adjustments	(7,950)	(8,004)
Proceeds from sales of loans	306,095	345,539
Loans originated for sale	(296,367)	(337,772)
Change in fair value of contingent consideration liability	0	(310)
(Increase) decrease in other assets	(20,903)	(9,548)
Increase (decrease) in other liabilities	19,256	6,537
Net cash provided by (used in) operating activities	58,435	43,557
Cash flows from investing activities:
Purchases of mortgage-backed securities available for sale	(96,867)	(35,213)
Purchases of other investment securities available for sale	(30,964)	(19,963)
Maturities and principal payments of mortgage-backed securities available for sale	63,918	62,745
Maturities and principal payments of other investment securities available for sale	6,795	21,269
Maturities and principal payments of mortgage-backed securities held to maturity	1,603	2,283
Remittance (purchases) of Federal Home Loan Bank stock	(4,008)	956
Net (increase) decrease in loans	(181,853)	(88,914)
Purchases of loans	(1,750)	(737)
Proceeds from the sale of property acquired through foreclosure or repossession	49	513
Purchases of premises and equipment	(2,320)	(2,184)
Purchases of bank-owned life insurance	(5,000)	0
Net cash provided by (used in) investing activities	(250,397)	(59,245)
Cash flows from financing activities:
Net increase (decrease) in deposits	171,641	93,329
Proceeds from Federal Home Loan Bank advances	1,462,500	1,000,000
Repayment of Federal Home Loan Bank advances	(1,425,464)	(1,034,885)
Payment for contingent consideration liability	(1,217)	0
Net proceeds from stock option exercises and issuance of other equity awards	(714)	194
Cash dividends paid	(21,856)	(19,567)
Net cash provided by (used in) financing activities	184,890	39,071
Net increase (decrease) in cash and cash equivalents	(7,072)	23,383
Cash and cash equivalents at beginning of period	82,923	107,797
Cash and cash equivalents at end of period	75,851	131,180
Noncash Investing and Financing Activities:
Loans charged off	889	1,415
Loans transferred to property acquired through foreclosure or repossession	3,074	576
Supplemental Disclosures:
Interest payments	28,596	21,512
Income tax payments	$ 12,585	$ 19,272

General Information

General Information	9 Months Ended
	Sep. 30, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
General Information	General Information Washington Trust Bancorp, Inc. (the “Bancorp”) is a publicly-owned registered bank holding company that has elected to be a financial holding company. The Bancorp’s subsidiaries include The Washington Trust Company, of Westerly (the “Bank”), a Rhode Island chartered commercial bank founded in 1800, and Weston Securities Corporation (“WSC”). Through its subsidiaries, the Bancorp offers a comprehensive product line of banking and financial services, including commercial, residential and consumer lending, retail and commercial deposit products, and wealth management services through its offices in Rhode Island, eastern Massachusetts and Connecticut; its automated teller machines (“ATMs”); telephone banking; mobile banking and its internet website (www.washtrust.com). The Unaudited Consolidated Financial Statements include the accounts of the Bancorp and its subsidiaries (collectively the “Corporation” or “Washington Trust”). All intercompany transactions have been eliminated. Certain previously reported amounts have been reclassified to conform to the current year’s presentation. The accounting and reporting policies of the Corporation conform to accounting principles generally accepted in the United States of America (“GAAP”) and to general practices of the banking industry. In preparing the financial statements, management is required to make estimates and assumptions that affect the reported amounts of assets and liabilities as of the date of the balance sheet and revenues and expenses for the period. Actual results could differ from those estimates. The Unaudited Consolidated Financial Statements of the Corporation presented herein have been prepared pursuant to the rules of the Securities and Exchange Commission (“SEC”) for quarterly reports on Form 10-Q and do not include all of the information and note disclosures required by GAAP. In the opinion of management, all adjustments (consisting of normal recurring adjustments) and disclosures considered necessary for the fair presentation of the accompanying Unaudited Consolidated Financial Statements have been included. Interim results are not necessarily reflective of the results of the entire year. The accompanying Unaudited Consolidated Financial Statements should be read in conjunction with the Audited Consolidated Financial Statements and notes thereto included in the Annual Report on Form 10-K for the fiscal year ended December 31, 2017 .

Recently Issued Accounting Pron

Recently Issued Accounting Pronouncements	9 Months Ended
	Sep. 30, 2018
New Accounting Pronouncements and Changes in Accounting Principles [Abstract]
Recently Issued Accounting Pronouncements	Recently Issued Accounting Pronouncements Revenue from Contracts with Customers - Topic 606 Accounting Standards Update No. 2014-09, “Revenue from Contracts with Customers” (“ASU 2014-09”), was issued in May 2014 and provides a revenue recognition framework for any entity that either enters into contracts with customers to transfer goods or services or enters into contracts for the transfer of non-financial assets unless those contracts are within the scope of other accounting standards. As issued, ASU 2014-09 was effective for annual periods beginning after December 15, 2016, including interim periods within that reporting period with early adoption not permitted. The standard permits the use of either the retrospective or cumulative effect transition method. In August 2015, Accounting Standards Update No. 2015-14, “Deferral of the Effective Date” (“ASU 2015-14”) was issued and delayed the effective date of ASU 2014-09 to annual and interim periods in fiscal years beginning after December 15, 2017. In 2016, Accounting Standards Update No. 2016-08, “Principal versus Agent Considerations” (“ASU 2016-08”), Accounting Standards Update No. 2016-10, “Identifying Performance Obligations and Licensing” (“ASU 2016-10”) and Accounting Standards Update No. 2016-12, “Narrow-Scope Improvements and Practical Expedients” (“ASU 2016-12”) were issued. These ASUs did not change the core principle for revenue recognition in Topic 606; instead, the amendments provided more detailed guidance in a few areas and additional implementation guidance and examples to reduce the degree of judgment necessary to comply with Topic 606. The effective date and transition requirements for ASU 2016-08, ASU 2016-10 and ASU 2016-12 were the same as those provided by ASU 2015-14. Management assembled a project team to address the changes pursuant to Topic 606. The project team completed a scope assessment and contract review for in-scope revenue streams. Washington Trust's largest source of revenue is net interest income on financial assets and liabilities, which was explicitly excluded from the scope of this ASU. Revenue streams that were within the scope of Topic 606 include wealth management revenues, service charges on deposit accounts and card interchange fees. Management adopted the provisions of ASU 2014-09 effective January 1, 2018, using the modified retrospective transition method. The adoption did not have a material impact on the Corporation’s consolidated financial statements. See Note 12 for further details. Financial Instruments - Overall - Topic 825 Accounting Standards Update No. 2016-01, “Recognition and Measurement of Financial Assets and Financial Liabilities” (“ASU 2016-01”), was issued in January 2016 and provides revised guidance related to the accounting for and reporting of financial instruments. Some of the main provisions include: requiring most equity securities to be reported at fair value with unrealized gains and losses reported in the income statement; requiring separate presentation of financial assets and liabilities by measurement category and form (i.e. securities or loans); clarifying that entities must assess valuation allowances on a deferred tax asset related to available for sale debt securities in combination with their other deferred tax assets; and eliminating the requirement to disclose the method and significant assumptions used to estimate fair value for financial instruments measured at amortized cost on the balance sheet. ASU 2016-01 was effective for annual periods, and interim periods within those annual periods, beginning after December 15, 2017. Management adopted the provisions of ASU 2016-01 effective January 1, 2018. The adoption did not have a material impact on the Corporation’s consolidated financial statements. Accounting Standards Update No. 2018-03, “Technical Corrections and Improvements to Financial Instruments - Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities” (“ASU 2018-03”), was issued in February 2018 to clarify certain aspects of the guidance issued in ASU 2016-01. Companies, such as Washington Trust, were not required to adopt the provisions of ASU 2018-03 until the interim period beginning after June 15, 2018. However, early adoption was permitted, as long as ASU 2016-01 provisions were adopted. Management early adopted the provisions of ASU 2018-03 effective January 1, 2018. The adoption did not have an impact on the Corporation’s consolidated financial statements. Leases - Topic 842 Accounting Standards Update No. 2016-02, “Leases” (“ASU 2016-02”), was issued in February 2016 and provides revised guidance related to the accounting and reporting of leases. ASU 2016-02 requires lessees to recognize most leases on the balance sheet. The recognition, measurement and presentation of expenses and cash flows arising from a lease by a lessee will depend on its classification as a finance or operating lease. ASU 2016-02 requires a modified retrospective transition, with a number of practical expedients that entities may elect to apply. In January 2018, Accounting Standards Update No. 2018-01, “Leases (Topic 842): Land Easement Practical Expedient for Transition to Topic 842 (“ASU 2018-01”) was issued to address concerns about the costs and complexity of complying with the transition provisions of ASU 2016-02. In July 2018, Accounting Standards Update No. 2018-10, “Codification Improvements to Topic 842, Leases” (“ASU 2018-10”) was issued to provide more detailed guidance and additional clarification for implementing ASU 2016-02. Also in July 2018, Accounting Standards Update No. 2018-11, “Targeted Improvements” (“ASU 2018-11”) was issued and allows for an optional transition method in which the provisions of Topic 842 would be applied upon the adoption date and would not have to be retroactively applied to the earliest reporting period presented in the consolidated financial statements. The Corporation intends to use this optional transition method for the adoption of Topic 842. These ASUs are effective for annual periods, and interim periods within those annual periods, beginning after December 15, 2018. Management assembled a project team that meets regularly to address the changes pursuant to Topic 842. The Corporation rents premises used in business operations under non-cancelable operating leases, which currently are not reflected in its Consolidated Balance Sheets. As disclosed in Note 18 , the Corporation was committed to $36.6 million of future minimum lease payments under these non-cancelable operating leases. Upon adoption of ASU 2016-02 on January 1, 2019, the Corporation expects to report increased assets and liabilities as a result of recognizing right-of-use assets and lease liabilities in its Consolidated Balance Sheets. The Corporation does not expect a material change to the timing of expense recognition in the Consolidated Statements of Income. Financial Instruments - Credit Losses - Topic 326 Accounting Standards Update No. 2016-13, “Financial Instruments - Credit Losses” (“ASU 2016-13”), was issued in June 2016. ASU 2016-13 requires the measurement of all expected credit losses for financial assets held at the reporting date based on historical experience, current conditions, and reasonable and supportable forecasts and requires enhanced disclosures related to the significant estimates and judgments used in estimating credit losses, as well as the credit quality and underwriting standards of an organization’s portfolio. In addition, ASU 2016-13 amends the accounting for credit losses on available-for-sale debt securities and purchased financial assets with credit deterioration. ASU 2016-13 provides for a modified retrospective transition, resulting in a cumulative-effect adjustment to equity as of the beginning of the period in which the guidance is effective, except for debt securities for which an other-than-temporary impairment has previously been recognized. For these debt securities, a prospective transition approach will be adopted in order to maintain the same amortized cost prior to and subsequent to the effective date of ASU 2016-13. This ASU is effective for annual periods, and interim periods within those annual periods, beginning after December 15, 2019, with early adoption permitted in 2019. Washington Trust is evaluating the effect that this ASU will have on consolidated financial statements and disclosures. Management assembled a project team that meets regularly to evaluate the provisions of this ASU, to address the additional data requirements necessary and to determine the approach for implementation. The Corporation does not plan to early adopt ASU 2016-13 and it has not yet determined the impact it will have on its consolidated financial statements. Statement of Cash Flows - Topic 230 Accounting Standards Update No. 2016-15, “Classification of Certain Cash Receipts and Cash Payments” (“ASU 2016-15”), was issued in August 2016. ASU 2016-15 provides classification guidance on certain cash receipts and cash payments, including, but not limited to, debt prepayment costs, contingent consideration payments made after a business combination, proceeds from the settlement of insurance claims, proceeds from the settlement of bank-owned life insurance policies and distributions received from equity method investees. The adoption of ASU 2016-15 requires a retrospective transition method applied to each period presented. This ASU was effective for annual periods, and interim periods within those annual periods, beginning after December 15, 2017. Management adopted the provisions of ASU 2016-15 effective January 1, 2018. The adoption did not have a material impact on the Corporation’s consolidated financial statements. Accounting Standards Update No. 2016-18, “Restricted Cash” (“ASU 2016-18”), was issued in November 2016. ASU 2016-18 requires that a statement of cash flows explain the change during the period in the total of cash, cash equivalents and amounts generally described as restricted cash. Restricted cash should be included with cash and cash equivalents when reconciling the beginning-of-period and end-of-period total amounts shown on the statement of cash flows. The adoption of ASU 2016-18 requires a retrospective transition method applied to each period presented. This ASU was effective for annual periods, and interim periods within those annual periods, beginning after December 15, 2017. Management adopted the provisions of ASU 2016-18 effective January 1, 2018. The adoption did not have a material impact on the Corporation’s consolidated financial statements. Compensation - Retirement Benefits - Topic 715 Accounting Standards Update No. 2017-07, “Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost” (“ASU 2017-07”), was issued in March 2017. ASU 2017-07 requires that employers include the service cost component of net periodic benefit cost in the same line item as other employee compensation costs and all other components of net periodic benefit cost in a separate line item(s) in the statement of income. In addition, the line item in which the components of net periodic benefit cost other than the service cost are included shall be identified as such on the statement of income or in the notes to the financial statements. ASU 2017-07 was effective for annual periods, and interim periods within those annual periods, beginning after December 15, 2017 requiring retrospective application for all periods presented. Management adopted the provisions of ASU 2017-07 effective January 1, 2018, utilizing the practical expedient that permitted employers to use the amounts previously disclosed in notes to financial statements as an estimation basis for applying the retrospective application requirements. The adoption of ASU 2017-07 resulted in an increase in salaries and employee benefits, a decrease in other expenses and no change to net income. The adoption did not have a material impact on the Corporation’s consolidated financial statements. See Note 13 for further details. Accounting Standards Update No. 2018-14, “Disclosure Framework - Changes to the Disclosure Requirements for Defined Benefit Plans” (“ASU 2018-14”), was issued in August 2018 to modify the disclosure requirements associated with defined benefit pension plans and other postretirement plans. ASU 2018-13 is effective for fiscal years ending after December 15, 2020, with early adoption permitted. The provisions under ASU 2018-13 are required to be applied retrospectively. The adoption of ASU 2018-14 is not expected to have a material impact on the Corporation’s consolidated financial statements. Compensation - Stock Compensation - Topic 718 Accounting Standards Update No. 2017-09, “Scope of Modification Accounting” (“ASU 2017-09”), was issued in May 2017 to provide clarity when applying the guidance in Topic 718 to a change to the terms or conditions of a share-based payment award. ASU 2017-09 was effective for annual periods, and interim periods within those annual periods, beginning after December 15, 2017 with provisions applied on a prospective basis. Management adopted the provisions of ASU 2017-09 effective January 1, 2018. The adoption did not have a material impact on the Corporation’s consolidated financial statements. Derivatives and Hedging - Topic 815 Accounting Standards Update No. 2017-12, “Targeted Improvements to Accounting for Hedging Activities” (“ASU 2017-12”), was issued in August 2017 to better align financial reporting for hedging activities with the economic objectives of those activities. ASU 2017-12 is effective for fiscal years beginning after December 15, 2018, with early adoption, including adoption in an interim period, permitted. The provisions of ASU 2017-12 should be applied on a modified retrospective transition method in which the Corporation will recognize the cumulative effect of the change in the opening balance of retained earnings as of the adoption date. The Corporation has not yet determined the impact ASU 2017-12 will have on its consolidated financial statements. Fair Value Measurement - Topic 820 Accounting Standards Update No. 2018-13, “Disclosure Framework - Changes to the Disclosure Requirements for Fair Value Measurement” (“ASU 2018-13”), was issued in August 2018 to modify the disclosure requirements related to fair value. ASU 2018-13 is effective for fiscal years beginning after December 15, 2019, with early adoption permitted, including adoption in an interim period. Certain provisions under ASU 2018-13 require prospective application, while other provisions require retrospective application to all periods presented in the consolidated financial statements upon adoption. The adoption of ASU 2018-13 is not expected to have a material impact on the Corporation’s consolidated financial statements. Intangibles - Goodwill and Other - Internal-Use Software - Topic 350 Accounting Standards Update No. 2018-15, “Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement that is a Service Contract” (“ASU 2018-15”), was issued in August 2018 to align the requirements for capitalizing implementation costs incurred in a hosting arrangement that is a service contract with those requirements that currently exist in GAAP for capitalizing implementation costs incurred to develop or obtain internal-use software. Implementation costs would either be capitalized or expensed as incurred depending on the project stage. All costs in the preliminary and post-implementation project stages are expensed as incurred, while certain costs within the application development stage are capitalized. ASU 2018-15 is effective for fiscal years beginning after December 15, 2019, with early adoption permitted, including adoption in an interim period. The adoption of ASU 2018-15 is not expected to have a material impact on the Corporation’s consolidated financial statements.

Cash and Due from Banks

Cash and Due from Banks	9 Months Ended
	Sep. 30, 2018
Cash and Cash Equivalents [Abstract]
Cash and Due from Banks	Cash and Due from Banks The Bank maintains certain average reserve balances to meet the requirements of the Board of Governors of the Federal Reserve System (“FRB”). Some or all of these reserve requirements may be satisfied with vault cash. Reserve balances am ounted to $20.7 million at September 30, 2018 and $14.1 million at December 31, 2017 and were included in cash and due from banks in the Unaudited Consolidated Balance Sheets. As of September 30, 2018 and December 31, 2017 , cash and due from banks included interest-bearing deposits in other banks of $20.8 million and $31.9 million , respectively.

Securities

Securities	9 Months Ended
	Sep. 30, 2018
Investments, Debt and Equity Securities [Abstract]
Securities	Securities The following tables present the amortized cost, gross unrealized holding gains, gross unrealized holding losses and fair value of securities by major security type and class of security: (Dollars in thousands) September 30, 2018 Amortized Cost Unrealized Gains Unrealized Losses Fair Value Securities Available for Sale: Obligations of U.S. government-sponsored enterprises $201,398 $9 ($7,934 ) $193,473 Mortgage-backed securities issued by U.S. government agencies and U.S. government-sponsored enterprises 616,552 1,143 (24,833 ) 592,862 Obligations of states and political subdivisions 935 2 — 937 Individual name issuer trust preferred debt securities 13,303 — (839 ) 12,464 Corporate bonds 13,911 — (1,000 ) 12,911 Total securities available for sale $846,099 $1,154 ($34,606 ) $812,647 Held to Maturity: Mortgage-backed securities issued by U.S. government agencies and U.S. government-sponsored enterprises $10,863 $— ($206 ) $10,657 Total securities held to maturity $10,863 $— ($206 ) $10,657 Total securities $856,962 $1,154 ($34,812 ) $823,304 (Dollars in thousands) December 31, 2017 Amortized Cost Unrealized Gains Unrealized Losses Fair Value Securities Available for Sale: Obligations of U.S. government-sponsored enterprises $161,479 $— ($3,875 ) $157,604 Mortgage-backed securities issued by U.S. government agencies and U.S. government-sponsored enterprises 594,944 3,671 (7,733 ) 590,882 Obligations of states and political subdivisions 2,355 4 — 2,359 Individual name issuer trust preferred debt securities 18,106 — (1,122 ) 16,984 Corporate bonds 13,917 13 (805 ) 13,125 Total securities available for sale $790,801 $3,688 ($13,535 ) $780,954 Held to Maturity: Mortgage-backed securities issued by U.S. government agencies and U.S. government-sponsored enterprises $12,541 $180 $— $12,721 Total securities held to maturity $12,541 $180 $— $12,721 Total securities $803,342 $3,868 ($13,535 ) $793,675 As of September 30, 2018 and December 31, 2017 , securities with a fair value of $356.5 million and $357.8 million , respectively, were pledged as collateral for Federal Home Loan Bank of Boston (“FHLB”) borrowings, potential borrowings with the FRB, certain public deposits and for other purposes. See Note 7 for additional disclosure on FHLB borrowings. The schedule of maturities of debt securities available for sale and held to maturity is presented below. Mortgage-backed securities are included based on weighted average maturities, adjusted for anticipated prepayments. All other debt securities are included based on contractual maturities. Actual maturities may differ from amounts presented because certain issuers have the right to call or prepay obligations with or without call or prepayment penalties. (Dollars in thousands) Available for Sale Held to Maturity September 30, 2018 Amortized Cost Fair Value Amortized Cost Fair Value Due in one year or less $64,023 $61,577 $1,370 $1,344 Due after one year to five years 314,353 302,124 4,529 4,443 Due after five years to ten years 278,106 266,878 3,709 3,639 Due after ten years 189,617 182,068 1,255 1,231 Total securities $846,099 $812,647 $10,863 $10,657 Included in the above table are debt securities with an amortized cost balance of $228.6 million and a fair value of $218.9 million at September 30, 2018 that are callable at the discretion of the issuers. Final maturities of the callable securities range from 8 months to 18 years, with call features ranging from 1 month to 3 years. Other-Than-Temporary Impairment Assessment Washington Trust assesses whether the decline in fair value of investment securities is other-than-temporary on a regular basis. Unrealized losses on debt securities may occur from current market conditions, increases in interest rates since the time of purchase, a structural change in an investment, volatility of earnings of a specific issuer, or deterioration in credit quality of the issuer. Management evaluates impairments in value both qualitatively and quantitatively to assess whether they are other-than-temporary. The following tables summarize temporarily impaired securities, segregated by length of time the securities have been in a continuous unrealized loss position: (Dollars in thousands) Less than 12 Months 12 Months or Longer Total September 30, 2018 # Fair Unrealized # Fair Value Unrealized Losses # Fair Value Unrealized Losses Obligations of U.S. government-sponsored enterprises 8 $77,958 ($2,040 ) 11 $105,606 ($5,894 ) 19 $183,564 ($7,934 ) Mortgage-backed securities issued by U.S. government agencies and U.S. government-sponsored enterprises 37 235,900 (6,567 ) 34 304,937 (18,472 ) 71 540,837 (25,039 ) Individual name issuer trust preferred debt securities — — — 5 12,464 (839 ) 5 12,464 (839 ) Corporate bonds 4 1,706 (13 ) 5 11,205 (987 ) 9 12,911 (1,000 ) Total temporarily impaired securities 49 $315,564 ($8,620 ) 55 $434,212 ($26,192 ) 104 $749,776 ($34,812 ) (Dollars in thousands) Less than 12 Months 12 Months or Longer Total December 31, 2017 # Fair Value Unrealized Losses # Fair Value Unrealized Losses # Fair Value Unrealized Losses Obligations of U.S. government-sponsored enterprises 8 $69,681 ($798 ) 8 $87,923 ($3,077 ) 16 $157,604 ($3,875 ) Mortgage-backed securities issued by U.S. government agencies and U.S. government-sponsored enterprises 20 128,965 (613 ) 22 279,693 (7,120 ) 42 408,658 (7,733 ) Individual name issuer trust preferred debt securities — — — 7 16,984 (1,122 ) 7 16,984 (1,122 ) Corporate bonds 3 921 (5 ) 3 10,980 (800 ) 6 11,901 (805 ) Total temporarily impaired securities 31 $199,567 ($1,416 ) 40 $395,580 ($12,119 ) 71 $595,147 ($13,535 ) Further deterioration in credit quality of the underlying issuers of the securities, deterioration in the condition of the financial services industry, worsening of the current economic environment, or additional declines in real estate values, among other things, may further affect the fair value of these securities and increase the potential that certain unrealized losses be designated as other-than-temporary in future periods, and the Corporation may incur write-downs. U.S. Government Agency and U.S. Government-Sponsored Enterprise Securities, including Mortgage-Backed Securities The gross unrealized losses on U.S. government agency and U.S government-sponsored debt securities, including mortgage-backed securities, were primarily attributable to relative changes in interest rates since the time of purchase. The contractual cash flows for these securities are guaranteed by U.S. government agencies and U.S. government-sponsored enterprises. Management believes that the unrealized losses on these debt security holdings are a function of changes in investment spreads and interest rate movements and not changes in credit quality. Management expects to recover the entire amortized cost basis of these securities. Furthermore, Washington Trust does not intend to sell these securities and it is not more-likely-than-not that Washington Trust will be required to sell these securities before recovery of their cost basis, which may be maturity. Therefore, management does not consider these investments to be other-than-temporarily impaired at September 30, 2018 . Trust Preferred Debt Securities of Individual Name Issuers Included in debt securities in an unrealized loss position at September 30, 2018 were five trust preferred securities issued by four individual companies in the banking sector. Management believes the unrealized losses on these holdings were attributable to the general widening of spreads for this category of debt securities issued by financial services companies since the time these securities were purchased. Based on the information available through the filing date of this report, all individual name issuer trust preferred debt securities held in our portfolio continue to accrue interest and make payments as expected with no payment deferrals or defaults on the part of the issuers. As of September 30, 2018 , individual name issuer trust preferred debt securities with an amortized cost of $6.1 million and unrealized losses of $411 thousand were rated below investment grade by Standard & Poors, Inc. (“S&P”). Management reviewed the collectibility of these securities taking into consideration such factors as the financial condition of the issuers, reported regulatory capital ratios of the issuers, credit ratings, including ratings in effect as of the reporting period date as well as credit rating changes between the reporting period date and the filing date of this report, and other information. We noted no additional downgrades to below investment grade between September 30, 2018 and the filing date of this report. Based on this review, management concluded that it expects to recover the entire amortized cost basis of these securities. Furthermore, Washington Trust does not intend to sell these securities and it is not more-likely-than-not that Washington Trust will be required to sell these securities before recovery of their cost basis, which may be maturity. Therefore, management does not consider these investments to be other-than-temporarily impaired at September 30, 2018 . Corporate Bonds At September 30, 2018 , Washington Trust had nine corporate bond holdings with unrealized losses totaling $1.0 million . These investment grade corporate bonds were issued by large corporations, primarily in the financial services industry. Management believes the unrealized losses on these bonds are a function of the changes in the investment spreads and interest rate movements and not changes in the credit quality of the issuers of the debt securities. Management expects to recover the entire amortized cost basis of these securities. Furthermore, Washington Trust does not intend to sell these securities and it is not more-likely-than-not that Washington Trust will be required to sell these securities before recovery of their cost basis, which may be maturity. Therefore, management does not consider these investments to be other-than-temporarily impaired at September 30, 2018 .

Loans

Loans	9 Months Ended
	Sep. 30, 2018
Receivables [Abstract]
Loans	Loans The following is a summary of loans: (Dollars in thousands) September 30, 2018 December 31, 2017 Amount % Amount % Commercial: Commercial real estate (1) $1,240,350 35 % $1,210,495 36 % Commercial & industrial (2) 656,882 18 612,334 18 Total commercial 1,897,232 53 1,822,829 54 Residential Real Estate: Residential real estate (3) 1,349,340 38 1,227,248 36 Consumer: Home equity 282,331 8 292,467 9 Other (4) 27,300 1 31,527 1 Total consumer 309,631 9 323,994 10 Total loans (5) $3,556,203 100 % $3,374,071 100 % (1) Commercial real estate loans consist of commercial mortgages primarily secured by income producing property, as well as construction and development loans. Construction and development loans are made to businesses for land development or the on-site construction of industrial, commercial, or residential buildings. (2) Commercial & industrial consist of loans to businesses and individuals, a substantial portion of which are fully or partially collateralized by real estate. (3) Residential real estate loans consist of mortgage and homeowner construction loans secured by one- to four- family residential properties. (4) Other consumer loans consists of loans to individuals secured by general aviation aircraft and other personal installment loans. (5) Includes net unamortized loan origination costs of $4.8 million and $3.8 million , respectively, at September 30, 2018 and December 31, 2017 and net unamortized premiums on purchased loans of $746 thousand and $878 thousand , respectively, at September 30, 2018 and December 31, 2017 . As of September 30, 2018 and December 31, 2017 , there were $1.9 billion and $1.6 billion , respectively, of loans pledged as collateral to the FHLB under a blanket pledge agreement and to the FRB for the discount window. See Note 7 for additional disclosure regarding borrowings. Past Due Loans Past due status is based on the contractual payment terms of the loan. The following tables present an age analysis of past due loans, segregated by class of loans: (Dollars in thousands) Days Past Due September 30, 2018 30-59 60-89 Over 90 Total Past Due Current Total Loans Commercial: Commercial real estate $— $931 $— $931 $1,239,419 $1,240,350 Commercial & industrial — 20 122 142 656,740 656,882 Total commercial — 951 122 1,073 1,896,159 1,897,232 Residential Real Estate: Residential real estate 5,322 2,936 1,140 9,398 1,339,942 1,349,340 Consumer: Home equity 1,854 534 551 2,939 279,392 282,331 Other 109 — — 109 27,191 27,300 Total consumer 1,963 534 551 3,048 306,583 309,631 Total loans $7,285 $4,421 $1,813 $13,519 $3,542,684 $3,556,203 (Dollars in thousands) Days Past Due December 31, 2017 30-59 60-89 Over 90 Total Past Due Current Total Loans Commercial: Commercial real estate $6 $— $4,954 $4,960 $1,205,535 $1,210,495 Commercial & industrial 3,793 2 281 4,076 608,258 612,334 Total commercial 3,799 2 5,235 9,036 1,813,793 1,822,829 Residential Real Estate: Residential real estate 1,678 2,274 3,903 7,855 1,219,393 1,227,248 Consumer: Home equity 2,798 75 268 3,141 289,326 292,467 Other 29 — 14 43 31,484 31,527 Total consumer 2,827 75 282 3,184 320,810 323,994 Total loans $8,304 $2,351 $9,420 $20,075 $3,353,996 $3,374,071 Included in past due loans as of September 30, 2018 and December 31, 2017 , were nonaccrual loans of $6.4 million and $11.8 million , respectively. All loans 90 days or more past due at September 30, 2018 and December 31, 2017 were classified as nonaccrual. Impaired Loans Impaired loans include nonaccrual loans and loans restructured in a troubled debt restructuring. The Corporation identifies loss allocations for impaired loans on an individual loan basis. The following is a summary of impaired loans: (Dollars in thousands) Recorded Investment (1) Unpaid Principal Related Allowance Sep 30, Dec 31, Sep 30, Dec 31, Sep 30, Dec 31, No Related Allowance Recorded Commercial: Commercial real estate $— $— $— $— $— $— Commercial & industrial 4,825 4,986 4,877 5,081 — — Total commercial 4,825 4,986 4,877 5,081 — — Residential Real Estate: Residential real estate 8,737 9,069 8,896 9,256 — — Consumer: Home equity 1,582 557 1,583 557 — — Other — 14 — 14 — — Total consumer 1,582 571 1,583 571 — — Subtotal 15,144 14,626 15,356 14,908 — — With Related Allowance Recorded Commercial: Commercial real estate $— $4,954 $— $9,910 $— $1,018 Commercial & industrial 54 191 75 212 — 1 Total commercial 54 5,145 75 10,122 — 1,019 Residential Real Estate: Residential real estate 692 715 722 741 101 104 Consumer: Home equity 52 — 51 — 8 — Other 23 133 23 132 3 6 Total consumer 75 133 74 132 11 6 Subtotal 821 5,993 871 10,995 112 1,129 Total impaired loans $15,965 $20,619 $16,227 $25,903 $112 $1,129 Total: Commercial $4,879 $10,131 $4,952 $15,203 $— $1,019 Residential real estate 9,429 9,784 9,618 9,997 101 104 Consumer 1,657 704 1,657 703 11 6 Total impaired loans $15,965 $20,619 $16,227 $25,903 $112 $1,129 (1) The recorded investment in impaired loans consists of unpaid principal balance, net of charge-offs, interest payments received applied to principal and unamortized deferred loan origination fees and costs. For accruing impaired loans (troubled debt restructurings for which management has concluded that the collectibility of the loan is not in doubt), the recorded investment also includes accrued interest. The following tables present the average recorded investment balance of impaired loans and interest income recognized on impaired loans segregated by loan class. (Dollars in thousands) Average Recorded Investment Interest Income Recognized Three months ended September 30, 2018 2017 2018 2017 Commercial: Commercial real estate $— $8,041 $— $21 Commercial & industrial 5,324 6,427 62 67 Total commercial 5,324 14,468 62 88 Residential Real Estate: Residential real estate 9,265 15,107 96 102 Consumer: Home equity 1,424 543 22 5 Other 25 142 — 2 Total consumer 1,449 685 22 7 Totals $16,038 $30,260 $180 $197 (Dollars in thousands) Average Recorded Investment Interest Income Recognized Nine months ended September 30, 2018 2017 2018 2017 Commercial: Commercial real estate $1,352 $9,117 $— $73 Commercial & industrial 5,599 6,750 201 219 Total commercial 6,951 15,867 201 292 Residential Real Estate: Residential real estate 9,709 15,750 293 374 Consumer: Home equity 1,045 734 41 25 Other 85 142 5 8 Total consumer 1,130 876 46 33 Totals $17,790 $32,493 $540 $699 Nonaccrual Loans Loans, with the exception of certain well-secured loans that are in the process of collection, are placed on nonaccrual status and interest recognition is suspended when such loans are 90 days or more overdue with respect to principal and/or interest, or sooner if considered appropriate by management. Well-secured loans are permitted to remain on accrual status provided that full collection of principal and interest is assured and the loan is in the process of collection. Loans are also placed on nonaccrual status when, in the opinion of management, full collection of principal and interest is doubtful. When loans are placed on nonaccrual status, interest previously accrued but not collected on such loans is reversed against current period income. Subsequent interest payments received on nonaccrual loans are applied to the outstanding principal balance of the loan or recognized as interest income depending on management’s assessment of the ultimate collectability of the loan. Loans are removed from nonaccrual status when they have been current as to principal and interest generally for a period of six months, the borrower has demonstrated an ability to comply with repayment terms, and when, in management’s opinion, the loans are considered to be fully collectible. The following is a summary of nonaccrual loans, segregated by class of loans: (Dollars in thousands) Sep 30, Dec 31, Commercial: Commercial real estate $— $4,954 Commercial & industrial 122 283 Total commercial 122 5,237 Residential Real Estate: Residential real estate 9,063 9,414 Consumer: Home equity 1,624 544 Other — 16 Total consumer 1,624 560 Total nonaccrual loans $10,809 $15,211 Accruing loans 90 days or more past due $— $— As of September 30, 2018 and December 31, 2017 , loans secured by one- to four-family residential property amounting to $816 thousand and $4.4 million , respectively, were in process of foreclosure. Nonaccrual loans of $4.4 million and $3.4 million , respectively, were current as to the payment of principal and interest at September 30, 2018 and December 31, 2017 . There were no significant commitments to lend additional funds to borrowers whose loans were on nonaccrual status at September 30, 2018 . Troubled Debt Restructurings Loans are considered restructured in a troubled debt restructuring when the Corporation has granted concessions, that it otherwise would not have considered, to a borrower experiencing financial difficulties. These concessions may include modifications of the terms of the debt such as deferral of payments, extension of maturity, reduction of principal balance, reduction of the stated interest rate other than normal market rate adjustments, or a combination of these concessions. Debt may be bifurcated with separate terms for each tranche of the restructured debt. Restructuring a loan in lieu of aggressively enforcing the collection of the loan may benefit the Corporation by increasing the ultimate probability of collection. Restructured loans are classified as accruing or non-accruing based on management’s assessment of the collectibility of the loan. Loans that are already on nonaccrual status at the time of the restructuring generally remain on nonaccrual status for approximately 6 months before management considers such loans for return to accruing status. Accruing restructured loans are placed into nonaccrual status if and when the borrower fails to comply with the restructured terms and management deems it unlikely that the borrower will return to a status of compliance in the near term. Troubled debt restructurings are reported as such for at least one year from the date of the restructuring. In years after the restructuring, troubled debt restructured loans are removed from this classification if the restructuring did not involve a below-market rate concession and the loan is not deemed to be impaired based on the terms specified in the restructuring agreement. The recorded investment in troubled debt restructurings consists of unpaid principal balance, net of charge-offs and unamortized deferred loan origination fees and costs, at the time of the restructuring. For accruing troubled debt restructured loans, the recorded investment also includes accrued interest. The recorded investment in troubled debt restructurings was $5.7 million and $11.2 million , respectively, at September 30, 2018 and December 31, 2017 . The allowance for loan losses included specific reserves for these troubled debt restructurings of $104 thousand and $1.1 million , respectively, at September 30, 2018 and December 31, 2017 . As of September 30, 2018 , there were no significant commitments to lend additional funds to borrowers whose loans had been restructured. For the three months ended September 30, 2018 , there were no loans modified as a troubled debt restructuring. For the nine months ended September 30, 2018 , there was one loan modified as a troubled debt restructuring with a pre-modification and post-modification recorded investment of $608 thousand . This troubled debt restructuring included a combination of concessions pertaining to maturity and interest only payment terms. There were no loans modified as a troubled debt restructuring for the three and nine months ended September 30, 2017 . For both the three and nine months ended September 30, 2018 , payment defaults on troubled debt restructured loans modified within the previous 12 months occurred on one loan with a carrying value of $608 thousand at the time of default. For the three months ended September 30, 2017 , there were no payment defaults on troubled debt restructured loans modified within the previous 12 months. For the nine months ended September 30, 2017 , payment defaults on troubled debt restructured loans modified within the previous 12 months occurred on two loans with a total carrying value of $1.6 million at the time of default. Credit Quality Indicators Commercial The Corporation utilizes an internal rating system to assign a risk to each of its commercial loans. Loans are rated on a scale of 1 to 10. This scale can be assigned to three broad categories including “pass” for ratings 1 through 6, “special mention” for 7-rated loans, and “classified” for loans rated 8, 9 or 10. The loan rating system takes into consideration parameters including the borrower’s financial condition, the borrower’s performance with respect to loan terms, the adequacy of collateral, the adequacy of guarantees and other credit quality characteristics. The weighted average risk rating of the Corporation’s commercial loan portfolio was 4.74 at September 30, 2018 and 4.70 at December 31, 2017 . For non-impaired loans, the Corporation takes the risk rating into consideration along with other credit attributes in the establishment of an appropriate allowance for loan losses. See Note 6 for additional information. A description of the commercial loan categories is as follows: Pass - Loans with acceptable credit quality, defined as ranging from superior or very strong to a status of lesser stature. Superior or very strong credit quality is characterized by a high degree of cash collateralization or strong balance sheet liquidity. Lesser stature loans have an acceptable level of credit quality but exhibit some weakness in various credit metrics such as collateral adequacy, cash flow, secondary sources of repayment, or performance inconsistency or may be in an industry or of a loan type known to have a higher degree of risk. Special Mention - Loans with potential weaknesses that deserve management’s close attention. If left uncorrected, these potential weaknesses may result in deterioration of the repayment prospects for the asset or in the Bank’s position as creditor at some future date. Special Mention assets are not adversely classified and do not expose the Bank to sufficient risk to warrant adverse classification. Examples of these conditions include but are not limited to outdated or poor quality financial data, strains on liquidity and leverage, losses or negative trends in operating results, marginal cash flow, weaknesses in occupancy rates or trends in the case of commercial real estate and frequent delinquencies. Classified - Loans identified as “substandard,” “doubtful” or “loss” based on criteria consistent with guidelines provided by banking regulators. A “substandard” loan has defined weaknesses which make payment default or principal exposure likely, but not yet certain. Such loans are apt to be dependent upon collateral liquidation, a secondary source of repayment or an event outside of the normal course of business. The loans are closely watched and are either already on nonaccrual status or may be placed on nonaccrual status when management determines there is uncertainty of collectibility. A “doubtful” loan is placed on nonaccrual status and has a high probability of loss, but the extent of the loss is difficult to quantify due to dependency upon collateral having a value that is difficult to determine or upon some near-term event which lacks certainty. A loan in the “loss” category is considered generally uncollectible or the timing or amount of payments cannot be determined. “Loss” is not intended to imply that the loan has no recovery value, but rather, it is not practical or desirable to continue to carry the asset. The Corporation’s procedures call for loan ratings and classifications to be revised whenever information becomes available that indicates a change is warranted. On a quarterly basis, management reviews the criticized loan portfolio, which generally consists of commercial loans that are risk-rated special mention or worse, and other selected loans. Management’s review focuses on the current status of the loans and strategies to improve the credit. An annual loan review program is conducted by a third party to provide an independent evaluation of the creditworthiness of the commercial loan portfolio, the quality of the underwriting and credit risk management practices and the appropriateness of the risk rating classifications. This review is supplemented with selected targeted internal reviews of the commercial loan portfolio. The following table presents the commercial loan portfolio, segregated by category of credit quality indicator: (Dollars in thousands) Pass Special Mention Classified Sep 30, Dec 31, Sep 30, Dec 31, Sep 30, Dec 31, Commercial: Commercial real estate 1,235,579 1,205,381 1,065 — 3,706 5,114 Commercial & industrial 593,673 592,749 55,012 9,804 8,197 9,781 Total commercial $1,829,252 $1,798,130 $56,077 $9,804 $11,903 $14,895 Residential and Consumer Management monitors the relatively homogeneous residential real estate and consumer loan portfolios on an ongoing basis using delinquency information by loan type. For non-impaired residential real estate and consumer loans, the Corporation assigns loss allocation factors to each respective loan type. See Note 6 for additional information. Other techniques are utilized to monitor indicators of credit deterioration in the residential real estate loans and consumer loan portfolios. Among these techniques is the periodic tracking of loans with an updated FICO score and an estimated loan to value (“LTV”) ratio. LTV ratio is determined via statistical modeling analyses. The indicated LTV levels are estimated based on such factors as the location, the original LTV ratio, and the date of origination of the loan and do not reflect actual appraisal amounts. The results of these analyses and other loan review procedures are taken into consideration in the determination of loss allocation factors for residential mortgage and home equity consumer credits. See Note 6 for additional information. The following table presents the residential and consumer loan portfolios, segregated by loan type and credit quality indicator: (Dollars in thousands) Current Past Due Sep 30, Dec 31, Sep 30, Dec 31, Residential Real Estate: Self-originated mortgages $1,224,575 $1,091,291 $8,172 $6,413 Purchased mortgages 115,367 128,102 1,226 1,442 Total residential real estate $1,339,942 $1,219,393 $9,398 $7,855 Consumer: Home equity $279,392 $289,326 $2,939 $3,141 Other 27,191 31,484 109 43 Total consumer $306,583 $320,810 $3,048 $3,184

Allowance for Loan Losses

Allowance for Loan Losses	9 Months Ended
	Sep. 30, 2018
Receivables [Abstract]
Allowance for Loan Losses	Allowance for Loan Losses The allowance for loan losses is management’s best estimate of incurred losses inherent in the loan portfolio as of the balance sheet date. The Corporation uses a methodology to systematically measure the amount of estimated loan loss exposure inherent in the loan portfolio for purposes of establishing a sufficient allowance for loan losses. The methodology includes: (1) the identification of loss allocations for individual loans deemed to be impaired and (2) the application of loss allocation factors for non-impaired loans based on historical loss experience and estimated loss emergence period, with adjustments for various exposures that management believes are not adequately represented by historical loss experience. The following table presents the activity in the allowance for loan losses for the three months ended September 30, 2018 : (Dollars in thousands) Commercial Consumer CRE (1) C&I (2) Total Commercial Residential Real Estate Home Equity Other Total Consumer Total Beginning Balance $12,443 $6,642 $19,085 $5,314 $1,375 $400 $1,775 $26,174 Charge-offs — (1 ) (1 ) (68 ) — (27 ) (27 ) (96 ) Recoveries — 71 71 — 2 8 10 81 Provision 1,052 535 1,587 (1,131 ) 12 (118 ) (106 ) 350 Ending Balance $13,495 $7,247 $20,742 $4,115 $1,389 $263 $1,652 $26,509 (1) Commercial real estate loans. (2) Commercial & industrial loans. The following table presents the activity in the allowance for loan losses for the nine months ended September 30, 2018 : (Dollars in thousands) Commercial Consumer CRE (1) C&I (2) Total Commercial Residential Real Estate Home Equity Other Total Consumer Total Beginning Balance $12,729 $5,580 $18,309 $5,427 $2,412 $340 $2,752 $26,488 Charge-offs (627 ) (8 ) (635 ) (73 ) (111 ) (70 ) (181 ) (889 ) Recoveries 25 104 129 — 12 19 31 160 Provision 1,368 1,571 2,939 (1,239 ) (924 ) (26 ) (950 ) 750 Ending Balance $13,495 $7,247 $20,742 $4,115 $1,389 $263 $1,652 $26,509 (1) Commercial real estate loans. (2) Commercial & industrial loans. The following table presents the activity in the allowance for loan losses for the three months ended September 30, 2017 : (Dollars in thousands) Commercial Consumer CRE (1) C&I (2) Total Commercial Residential Real Estate Home Equity Other Total Consumer Total Beginning Balance $11,935 $7,067 $19,002 $5,369 $1,927 $364 $2,291 $26,662 Charge-offs (535 ) (122 ) (657 ) — (18 ) (19 ) (37 ) (694 ) Recoveries — 8 8 1 25 6 31 40 Provision 1,387 (301 ) 1,086 70 (27 ) 171 144 1,300 Ending Balance $12,787 $6,652 $19,439 $5,440 $1,907 $522 $2,429 $27,308 (1) Commercial real estate loans. (2) Commercial & industrial loans. The following table presents the activity in the allowance for loan losses for the nine months ended September 30, 2017 : (Dollars in thousands) Commercial Consumer CRE (1) C&I (2) Total Commercial Residential Real Estate Home Equity Other Total Consumer Total Beginning Balance $11,166 $6,992 $18,158 $5,252 $1,889 $705 $2,594 $26,004 Charge-offs (935 ) (286 ) (1,221 ) (32 ) (79 ) (83 ) (162 ) (1,415 ) Recoveries 82 162 244 29 31 15 46 319 Provision 2,474 (216 ) 2,258 191 66 (115 ) (49 ) 2,400 Ending Balance $12,787 $6,652 $19,439 $5,440 $1,907 $522 $2,429 $27,308 (1) Commercial real estate loans. (2) Commercial & industrial loans. The following table presents the Corporation’s loan portfolio and associated allowance for loan loss by portfolio segment and by impairment methodology: (Dollars in thousands) September 30, 2018 December 31, 2017 Loans Related Allowance Loans Related Allowance Loans Individually Evaluated for Impairment Commercial: Commercial real estate $— $— $4,954 $1,018 Commercial & industrial 4,860 — 5,157 1 Total commercial 4,860 — 10,111 1,019 Residential Real Estate: Residential real estate 9,428 101 9,783 104 Consumer: Home equity 1,635 9 557 — Other 22 2 147 6 Total consumer 1,657 11 704 6 Subtotal 15,945 112 20,598 1,129 Loans Collectively Evaluated for Impairment Commercial: Commercial real estate 1,240,350 13,495 1,205,541 11,711 Commercial & industrial 652,022 7,247 607,177 5,579 Total commercial 1,892,372 20,742 1,812,718 17,290 Residential Real Estate: Residential real estate 1,339,912 4,014 1,217,465 5,323 Consumer: Home equity 280,696 1,380 291,910 2,412 Other 27,278 261 31,380 334 Total consumer 307,974 1,641 323,290 2,746 Subtotal 3,540,258 26,397 3,353,473 25,359 Total $3,556,203 $26,509 $3,374,071 $26,488

Borrowings

Borrowings	9 Months Ended
	Sep. 30, 2018
Debt Disclosure [Abstract]
Borrowings	Borrowings FHLB Advances Advances payable to the FHLB amounted to $828.4 million and $791.4 million , respectively, at September 30, 2018 and December 31, 2017 . The following table presents maturities and weighted average interest rates on FHLB advances outstanding as of September 30, 2018 : (Dollars in thousands) Total Outstanding Weighted Average Rate October 1, 2018 to December 31, 2018 $297,670 2.26 % 2019 347,258 2.15 2020 67,033 1.95 2021 46,222 2.57 2022 55,447 3.59 2023 and thereafter 14,762 2.29 Balance at September 30, 2018 $828,392 2.35 % As of September 30, 2018 and December 31, 2017 , the Bank had access to a $40.0 million unused line of credit with the FHLB and also had remaining available borrowing capacity of $601.0 million and $449.9 million , respectively. The Bank pledges certain qualified investment securities and loans as collateral to the FHLB.

Shareholders' Equity

Shareholders' Equity	9 Months Ended
	Sep. 30, 2018
Regulatory Capital Requirements [Abstract]
Regulatory Capital Requirements	Shareholders’ Equity Regulatory Capital Requirements At both September 30, 2018 and December 31, 2017 , the Corporation and the Bank were considered “well capitalized.” The following table presents the Corporation’s and the Bank’s actual capital amounts and ratios, as well as the corresponding minimum and well capitalized regulatory amounts and ratios that were in effect during the respective periods: (Dollars in thousands) Actual For Capital Adequacy Purposes To Be “Well Capitalized” Under Prompt Corrective Action Provisions Amount Ratio Amount Ratio Amount Ratio September 30, 2018 Total Capital (to Risk-Weighted Assets): Corporation $445,448 12.77 % $279,165 8.00 % N/A N/A Bank 442,337 12.68 279,145 8.00 $348,931 10.00 % Tier 1 Capital (to Risk-Weighted Assets): Corporation 418,649 12.00 209,374 6.00 N/A N/A Bank 415,538 11.91 209,358 6.00 279,145 8.00 Common Equity Tier 1 Capital (to Risk-Weighted Assets): Corporation 396,651 11.37 157,031 4.50 N/A N/A Bank 415,538 11.91 157,019 4.50 226,805 6.50 Tier 1 Capital (to Average Assets): (1) Corporation 418,649 8.91 187,898 4.00 N/A N/A Bank 415,538 8.85 187,858 4.00 234,822 5.00 December 31, 2017 Total Capital (to Risk-Weighted Assets): Corporation 416,038 12.45 267,365 8.00 N/A N/A Bank 413,593 12.38 267,338 8.00 334,172 10.00 Tier 1 Capital (to Risk-Weighted Assets): Corporation 389,289 11.65 200,524 6.00 N/A N/A Bank 386,844 11.58 200,503 6.00 267,338 8.00 Common Equity Tier 1 Capital (to Risk-Weighted Assets): Corporation 367,291 10.99 150,383 4.50 N/A N/A Bank 386,844 11.58 150,378 4.50 217,212 6.50 Tier 1 Capital (to Average Assets): (1) Corporation 389,289 8.79 177,089 4.00 N/A N/A Bank 386,844 8.74 177,048 4.00 221,310 5.00 (1) Leverage ratio. In addition to the minimum regulatory capital required for capital adequacy purposes included in the table above, the Corporation is required to maintain a minimum capital conservation buffer, in the form of common equity, in order to avoid restrictions on capital distributions and discretionary bonuses. The required amount of the capital conservation buffer was 1.25% on January 1, 2017 and 1.875% on January 1, 2018. The capital conservation buffer will increase another 0.625% on January 1, 2019 to reach the full requirement of 2.50%.

Derivative Financial Instrument

Derivative Financial Instruments	9 Months Ended
	Sep. 30, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Financial Instruments	Derivative Financial Instruments The Corporation’s derivative financial instruments are used to manage differences in the amount, timing and duration of the Corporation’s known or expected cash receipts and its known or expected cash payments principally to manage the Corporation’s interest rate risk. Additionally, the Corporation enters into interest rate derivatives to accommodate the business requirements of its customers. All derivatives are recognized as either assets or liabilities on the balance sheet and are measured at fair value. The accounting for changes in the fair value of derivatives depends on the intended use of the derivative and resulting designation. Interest Rate Risk Management Agreements Interest rate risk management agreements, such as caps, swaps, and floors, are used from time to time as part of the Corporation’s interest rate risk management strategy. Interest rate swaps are agreements in which the Corporation and another party agree to exchange interest payments (e.g., fixed-rate for variable-rate payments) computed on a notional principal amount. Interest rate caps and floors represent options purchased by the Corporation to manage the interest rate paid throughout the term of the option contract. The credit risk associated with these transactions is the risk of default by the counterparty. To minimize this risk, the Corporation enters into interest rate agreements only with highly rated counterparties that management believes to be creditworthy. The notional amounts of these agreements do not represent amounts exchanged by the parties and, thus, are not a measure of the potential loss exposure. Cash Flow Hedging Instruments As of September 30, 2018 and December 31, 2017 , the Bancorp had two interest rate caps with a total notional amount of $22.7 million that were designated as cash flow hedges to hedge the interest rate risk associated with our variable rate junior subordinated debentures. For both interest rate caps, the Bancorp obtained the right to receive the difference between 3-month LIBOR and a 4.5% strike. The caps mature in 2020. As of September 30, 2018 and December 31, 2017 , the Bank had two interest rate swap contracts with a total notional amount of $60.0 million that were designated as cash flow hedges to hedge the interest rate risk associated with short-term variable rate FHLB advances. The interest rate swaps mature in 2021 and 2023. As of September 30, 2018 and December 31, 2017 , the Bank had three interest rate floor contracts with a total notional amount of $300.0 million that were designated as cash flow hedges to hedge the interest rate risk associated with a pool of variable rate commercial loans. The Bank obtained the right to receive the difference between 1-month LIBOR and a 1.0% strike for each of the interest rate floors. The floors mature in 2020. The effective portion of the changes in fair value of derivatives designated as cash flow hedges is recorded in other comprehensive income and subsequently reclassified to earnings when gains or losses are realized. The ineffective portion of changes in fair value of the derivatives is recognized directly in earnings. For the three and nine months ended September 30, 2018 and 2017 , there was no ineffectiveness recorded in earnings. Loan Related Derivative Contracts Interest Rate Swap Contracts with Customers The Corporation has entered into interest rate swap contracts to help commercial loan borrowers manage their interest rate risk. The interest rate swap contracts with commercial loan borrowers allow them to convert variable-rate loan payments to fixed-rate loan payments. When we enter into an interest rate swap contract with a commercial loan borrower, we simultaneously enter into a “mirror” swap contract with a third party. The third party exchanges the client’s fixed-rate loan payments for variable-rate loan payments. We retain the risk that is associated with the potential failure of counterparties and the risk inherent in originating loans. As of September 30, 2018 and December 31, 2017 , Washington Trust had interest rate swap contracts with commercial loan borrowers with notional amounts of $574.4 million and $ 545.0 million , respectively, and equal amounts of “mirror” swap contracts with third-party financial institutions. These derivatives are not designated as hedges and therefore, changes in fair value are recognized in earnings. Risk Participation Agreements The Corporation has entered into risk participation agreements with other banks in commercial loan arrangements. Participating banks guarantee the performance on borrower-related interest rate swap contracts. These derivatives are not designated as hedges and therefore, changes in fair value are recognized in earnings. Under a risk participation-out agreement, a derivative asset, the Corporation participates out a portion of the credit risk associated with the interest rate swap position executed with the commercial borrower for a fee paid to the participating bank. Under a risk participation-in agreement, a derivative liability, the Corporation assumes, or participates in, a portion of the credit risk associated with the interest rate swap position with the commercial borrower for a fee received from the other bank. As of September 30, 2018 , the notional amounts of risk participation-out agreements and risk participation-in agreements were $51.5 million and $36.6 million , respectively, compared to $52.4 million and $34.1 million , respectively, as of December 31, 2017 . Foreign Exchange Contracts Foreign exchange contracts represent contractual commitments to buy or sell a foreign currency on a future date at a specified price. The Corporation uses these foreign exchange contracts on a limited basis to reduce its exposure to fluctuations in currency exchange rates associated with a commercial loan that is denominated in a foreign currency. These derivatives are not designated as hedges and therefore changes in fair value are recognized in earnings. The changes in fair value on the foreign exchange contracts substantially offset the foreign currency translation gains and losses on the related commercial loan. As of September 30, 2018 and December 31, 2017 , the notional amount of foreign exchange contracts was $2.9 million and $3.0 million , respectively. Loan Commitments Interest rate lock commitments are extended to borrowers and relate to the origination of residential real estate mortgage loans held for sale. To mitigate the interest rate risk and pricing risk associated with rate locks and residential real estate mortgage loans held for sale, the Corporation enters into forward sale commitments. Forward sale commitments are contracts for delayed delivery or net settlement of the underlying instrument, such as a residential real estate mortgage loan, where the seller agrees to deliver on a specified future date, either a specified instrument at a specified price or yield or the net cash equivalent of an underlying instrument. Both interest rate lock commitments and forward sale commitments are derivative financial instruments, but do not meet criteria for hedge accounting and, as such the changes in fair value of these commitments are reflected in earnings. The following table presents the fair values of derivative instruments in the Corporation’s Unaudited Consolidated Balance Sheets: (Dollars in thousands) Asset Derivatives Liability Derivatives Fair Value Fair Value Balance Sheet Location Sep 30, 2018 Dec 31, 2017 Balance Sheet Location Sep 30, 2018 Dec 31, 2017 Derivatives Designated as Cash Flow Hedging Instruments: Interest rate risk management contracts: Interest rate caps Other assets $83 $25 Other liabilities $— $— Interest rate swaps Other assets 1,947 213 Other liabilities — 14 Interest rate floors Other assets 14 110 Other liabilities — — Derivatives not Designated as Hedging Instruments: Loan related derivative contracts: Interest rate swaps with customers Other assets 33 268 Other liabilities 17,522 1,295 Mirror swaps with counterparties Other assets 17,342 1,152 Other liabilities 33 268 Risk participation agreements Other assets — — Other liabilities — — Foreign exchange contracts Other assets 37 — Other liabilities — 26 Forward loan commitments: Interest rate lock commitments Other assets 618 965 Other liabilities 1 20 Forward sale commitments Other assets 168 26 Other liabilities 266 1,424 Total $20,242 $2,759 $17,822 $3,047 The following tables present the effect of derivative instruments in the Corporation’s Unaudited Consolidated Statements of Changes in Shareholders’ Equity and Unaudited Consolidated Statements of Income: (Dollars in thousands) Gain (Loss) Recognized in Other Comprehensive Income, Net of Tax (Effective Portion) Three Months Nine Months Periods ended September 30, 2018 2017 2018 2017 Derivatives Designated as Cash Flow Hedging Instruments: Interest rate risk management contracts: Interest rate caps $17 ($7 ) $66 ($64 ) Interest rate swaps 189 74 1,322 (26 ) Interest rate floors (51 ) (80 ) 21 (274 ) Total $155 ($13 ) $1,409 ($364 ) (Dollars in thousands) Amount of Gain (Loss) Recognized in Income on Derivatives Three Months Nine Months Periods ended September 30, Statement of Income Location 2018 2017 2018 2017 Derivatives not Designated as Hedging Instruments: Loan related derivative contracts: Interest rate swaps with customers Loan related derivative income ($3,178 ) $1,917 (15,374 ) 5,583 Mirror swaps with counterparties Loan related derivative income 3,415 (505 ) 16,384 (2,578 ) Risk participation agreements Loan related derivative income 25 40 25 (261 ) Foreign exchange contracts Loan related derivative income 16 — 52 — Forward loan commitments: Interest rate lock commitments Mortgage banking revenues (504 ) 32 ($327 ) $639 Forward sale commitments Mortgage banking revenues 316 59 1,552 (1,321 ) Total $90 $1,543 $2,312 $2,062

Balance Sheet Offsetting

Balance Sheet Offsetting	9 Months Ended
	Sep. 30, 2018
Balance Sheet Offsetting [Abstract]
Balance Sheet Offsetting	Balance Sheet Offsetting For interest rate risk management contracts and loan-related derivative contracts, the Corporation records derivative assets and derivative liabilities on a net basis. The interest rate risk management contracts and loan related derivative contracts with counterparties are subject to master netting agreements. The following tables present the Corporation’s derivative asset and derivative liability positions and the effect of netting arrangements on the Unaudited Consolidated Balance Sheets: (Dollars in thousands) Gross Derivative Positions Offsetting Derivative Positions Net Amounts Presented in Balance Sheet Cash Collateral Pledged Net Amount September 30, 2018 Derivative Assets: Interest rate risk management contracts: Interest rate caps $83 $— $83 $— $83 Interest rate swaps 1,947 — 1,947 — 1,947 Interest rate floors 14 — 14 — 14 Loan-related derivative contracts: Interest rate swaps with customers 463 430 33 — 33 Mirror swaps with counterparties 17,784 442 17,342 — 17,342 Foreign exchange contracts 37 — 37 — 37 Total $20,328 $872 $19,456 $— $19,456 Derivative Liabilities: Loan-related derivative contracts: Interest rate swaps with customers $17,952 $430 $17,522 $— $17,522 Mirror swaps with counterparties 475 442 33 — 33 Total $18,427 $872 $17,555 $— $17,555 (Dollars in thousands) Gross Derivative Positions Offsetting Derivative Positions Net Amounts Presented in Balance Sheet Cash Collateral Pledged Net Amount December 31, 2017 Derivative Assets: Interest rate risk management contracts: Interest rate caps $25 $— $25 $— $25 Interest rate swaps 213 — 213 — 213 Interest rate floors 110 — 110 — 110 Loan-related derivative contracts: Interest rate swaps with customers 2,857 2,589 268 — 268 Mirror swaps with counterparties 3,801 2,649 1,152 — 1,152 Total $7,006 $5,238 $1,768 $— $1,768 Derivative Liabilities: Interest rate risk management contracts: Interest rate swaps $14 $— $14 $14 $— Loan-related derivative contracts: Interest rate swaps with customers 3,884 2,589 1,295 1,025 270 Mirror swaps with counterparties 2,917 2,649 268 — 268 Foreign exchange contracts 26 — 26 — 26 Total $6,841 $5,238 $1,603 $1,039 $564 As of September 30, 2018 , there was no pledged collateral to derivative counterparties in the form of cash. As of December 31, 2017 , Washington Trust pledged collateral to derivative counterparties in the form of cash totaling $1.0 million . Washington Trust may need to post additional collateral in the future in proportion to potential increases in unrealized loss positions.

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2018
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements The Corporation uses fair value measurements to record fair value adjustments on certain assets and liabilities and to determine fair value disclosures. As of September 30, 2018 and December 31, 2017 , securities available for sale, residential real estate mortgage loans held for sale, derivatives and the contingent consideration liability are recorded at fair value on a recurring basis. Additionally, from time to time, we may be required to record at fair value other assets on a nonrecurring basis, such as collateral dependent impaired loans, property acquired through foreclosure or repossession and mortgage servicing rights. These nonrecurring fair value adjustments typically involve the application of lower of cost or market accounting or write-downs of individual assets. Fair value is a market-based measurement, not an entity-specific measurement. Fair value measurements are determined based on the assumptions the market participants would use in pricing the asset or liability. In addition, GAAP specifies a hierarchy of valuation techniques based on whether the types of valuation information (“inputs”) are observable or unobservable. Observable inputs reflect market data obtained from independent sources, while unobservable inputs reflect the Corporation’s market assumptions. These two types of inputs have created the following fair value hierarchy: • Level 1 – Quoted prices for identical assets or liabilities in active markets. • Level 2 – Quoted prices for similar assets or liabilities in active markets; quoted prices for identical or similar assets or liabilities in inactive markets; and model-derived valuations in which all significant inputs and significant value drivers are observable in active markets. • Level 3 – Valuations derived from valuation techniques in which one or more significant inputs or significant value drivers are unobservable in the markets and which reflect the Corporation’s market assumptions. Fair Value Option Election GAAP allows for the irrevocable option to elect fair value accounting for the initial and subsequent measurement for certain financial assets and liabilities on a contract-by-contract basis. The Corporation has elected the fair value option for residential real estate mortgage loans held for sale to better match changes in fair value of the loans with changes in the fair value of the forward sale commitment contracts used to economically hedge them. The aggregate principal amount of the residential real estate mortgage loans held for sale recorded at fair value was $22.3 million and $26.4 million , respectively, at September 30, 2018 and December 31, 2017 . The aggregate fair value of these loans as of the same dates was $22.6 million and $26.9 million , respectively. As of September 30, 2018 and December 31, 2017 , the aggregate fair value of residential real estate mortgage loans held for sale exceeded the aggregate principal amount by $303 thousand and $543 thousand , respectively. There were no residential real estate mortgage loans held for sale 90 days or more past due as of September 30, 2018 and December 31, 2017 . Changes in fair value of mortgage loans held for sale accounted for under the fair value option election amounted to decreases of $352 thousand and $240 thousand , respectively, in the three and nine months ended September 30, 2018 , compared to a decrease of $81 thousand and an increase of $693 thousand , respectively, in the three and nine months ended September 30, 2017 . These amounts were partially offset in earnings by the changes in fair value of forward sale commitments used to economically hedge them. The changes in fair value are reported as a component of mortgage banking revenues in the Unaudited Consolidated Statements of Income. Valuation Techniques Securities Securities available for sale are recorded at fair value on a recurring basis. When available, the Corporation uses quoted market prices to determine the fair value of securities; such items are classified as Level 1. There were no Level 1 securities held at September 30, 2018 and December 31, 2017 . Level 2 securities include debt securities with quoted prices, which are traded less frequently than exchange-traded instruments. The fair value of these securities is determined using matrix pricing with inputs that are observable in the market or can be derived principally from or corroborated by observable market data. This category includes obligations of U.S. government-sponsored enterprises, including mortgage-backed securities, obligations of states and political subdivisions, individual name issuer trust preferred debt securities and corporate bonds. Securities not actively traded whose fair value is determined through the use of cash flows utilizing inputs that are unobservable are classified as Level 3. There were no Level 3 securities held at September 30, 2018 and December 31, 2017 . Mortgage Loans Held for Sale The fair value of mortgage loans held for sale is estimated based on current market prices for similar loans in the secondary market and therefore are classified as Level 2 assets. Collateral Dependent Impaired Loans The fair value of collateral dependent loans that are deemed to be impaired is determined based upon the fair value of the underlying collateral. Such collateral primarily consists of real estate and, to a lesser extent, other business assets. For collateral dependent loans for which repayment is dependent on the sale of the collateral, management adjusts the fair value for estimated costs to sell. For collateral dependent loans for which repayment is dependent on the operation of the collateral, such as accruing troubled debt restructured loans, estimated costs to sell are not incorporated into the measurement. Management may also adjust appraised values to reflect estimated market value declines or apply other discounts to appraised values resulting from its knowledge of the property. Internal valuations are utilized to determine the fair value of other business assets. Collateral dependent impaired loans are categorized as Level 3. Property Acquired Through Foreclosure or Repossession Property acquired through foreclosure or repossession included in other assets in the Unaudited Consolidated Balance Sheets is adjusted to fair value less costs to sell upon transfer out of loans through a charge to allowance for loan losses. Subsequently, it is carried at the lower of carrying value or fair value less costs to sell. Such subsequent valuation charges are charged through earnings. Fair value is generally based upon appraised values of the collateral. Management may adjust appraised values to reflect estimated market value declines or apply other discounts to appraised values for unobservable factors resulting from its knowledge of the property, and such property is categorized as Level 3. Derivatives Interest rate cap, swap and floor contracts are traded in over-the-counter markets where quoted market prices are not readily available. Fair value measurements are determined using independent pricing models that utilize primarily market observable inputs, such as swap rates of different maturities and LIBOR rates. The Corporation also evaluates the credit risk of its counterparties as well as that of the Corporation. Accordingly, Washington Trust considers factors such as the likelihood of default by the Corporation and its counterparties, its net exposures and remaining contractual life, among other factors, in determining if any fair value adjustments related to credit risk are required. Counterparty exposure is evaluated by netting positions that are subject to master netting agreements, as well as considering the amount of collateral securing the position, if any. Although the Corporation has determined that the majority of the inputs used to value its interest rate swap, cap and floor contracts fall within Level 2 of the fair value hierarchy, the credit valuation adjustments associated with interest rate contracts and risk participation agreements utilize Level 3 inputs, such as estimates of current credit spreads to evaluate the likelihood of default by the Corporation and its counterparties. However, as of September 30, 2018 and December 31, 2017 , the Corporation has assessed the significance of the impact of the credit valuation adjustments on the overall valuation of its derivative positions and has determined that the credit valuation adjustments are not significant to the overall valuation of its derivatives. As a result, the Corporation has classified its derivative valuations in their entirety as Level 2. Fair value measurements of forward loan commitments (interest rate lock commitments and forward sale commitments) are primarily based on current market prices for similar assets in the secondary market for mortgage loans and therefore are classified as Level 2 assets. The fair value of interest rate lock commitments is also dependent on the ultimate closing of the loans. Pull-through rates are based on the Corporation’s historical data and reflect the Corporation’s best estimate of the likelihood that a commitment will result in a closed loan. Although the pull-through rates are Level 3 inputs, the Corporation has assessed the significance of the impact of pull-through rates on the overall valuation of its interest rate lock commitments and has determined that they are not significant to the overall valuation. As a result, the Corporation has classified its interest rate lock commitments as Level 2. Contingent Consideration Liability A contingent consideration liability was recognized upon the completion of the Halsey acquisition on August 1, 2015 representing the estimated present value of future earn-outs to be paid based on the future revenue growth of the acquired business during the five -year period following the acquisition. The fair value measurement is based upon unobservable inputs, therefore, the contingent liability is classified within Level 3 of the fair value hierarchy. The unobservable inputs include probability estimates regarding the likelihood of achieving revenue growth targets and the discount rates utilized the discounted cash flow calculations applied to the estimates earn-outs to be paid. The contingent consideration liability is remeasured to fair value at each reporting period taking into consideration changes in those unobservable inputs. Changes in the fair value of the contingent consideration liability are included in noninterest expenses in the Unaudited Consolidated Statements of Income. One of the two earn-out periods associated with this contingent consideration liability ended December 31, 2017 and a payment of $1.2 million was made by the Corporation in the first quarter of 2018. The fair value of the contingency represents the estimated price to transfer the liability between market participants at the measurement date under current market conditions. Items Recorded at Fair Value on a Recurring Basis The following tables present the balances of assets and liabilities reported at fair value on a recurring basis: (Dollars in thousands) Total Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) September 30, 2018 Assets: Securities available for sale: Obligations of U.S. government-sponsored enterprises $193,473 $— $193,473 $— Mortgage-backed securities issued by U.S. government agencies and U.S. government-sponsored enterprises 592,862 — 592,862 — Obligations of states and political subdivisions 937 — 937 — Individual name issuer trust preferred debt securities 12,464 — 12,464 — Corporate bonds 12,911 — 12,911 — Mortgage loans held for sale 22,571 — 22,571 — Derivative assets 20,242 — 20,242 — Total assets at fair value on a recurring basis $855,460 $— $855,460 $— Liabilities: Derivative liabilities $17,822 $— $17,822 $— Contingent consideration liability 187 — — 187 Total liabilities at fair value on a recurring basis $18,009 $— $17,822 $187 (Dollars in thousands) Total Quoted Prices in Active Markets for Identical Assets Significant Other Observable Inputs Significant Unobservable Inputs December 31, 2017 Assets: Securities available for sale: Obligations of U.S. government-sponsored enterprises $157,604 $— $157,604 $— Mortgage-backed securities issued by U.S. government agencies and U.S. government-sponsored enterprises 590,882 — 590,882 — Obligations of states and political subdivisions 2,359 — 2,359 — Individual name issuer trust preferred debt securities 16,984 — 16,984 — Corporate bonds 13,125 — 13,125 — Mortgage loans held for sale 26,943 — 26,943 — Derivative assets 2,759 — 2,759 — Total assets at fair value on a recurring basis $810,656 $— $810,656 $— Liabilities: Derivative liabilities $3,047 $— $3,047 $— Contingent consideration liability 1,404 — — 1,404 Total liabilities at fair value on a recurring basis $4,451 $— $3,047 $1,404 It is the Corporation’s policy to review and reflect transfers between Levels as of the financial statement reporting date. There were no transfers in and/or out of Level 1, 2 or 3 during the nine months ended September 30, 2018 and 2017 . The contingent consideration liability is a Level 3 liability remeasured to fair value on a recurring basis. The following table presents the change in the contingent consideration liability, which is included in other liabilities in the Unaudited Consolidated Balance Sheets. (Dollars in thousands) Three Months Nine Months Periods ended September 30, 2018 2017 2018 2017 Balance at beginning of period $187 $1,737 $1,404 $2,047 Change in fair value — — — (310 ) Payments — — (1,217 ) — Balance at end of period $187 $1,737 $187 $1,737 Items Recorded at Fair Value on a Nonrecurring Basis The following table presents the carrying value of assets held at September 30, 2018 , which were written down to fair value during the nine months ended September 30, 2018 : (Dollars in thousands) Total Quoted Prices in Active Markets for Identical Assets Significant Other Observable Inputs Significant Unobservable Inputs Assets: Collateral dependent impaired loans $27 $— $— $27 Property acquired through foreclosure or repossession 2,974 — — 2,974 Total assets at fair value on a nonrecurring basis $3,001 $— $— $3,001 The allowance for loan losses on collateral dependent impaired loans amounted to $8 thousand at September 30, 2018 . The following table presents the carrying value of assets held at December 31, 2017 , which were written down to fair value during the year ended December 31, 2017 : (Dollars in thousands) Total Quoted Prices in Active Markets for Identical Assets Significant Other Observable Inputs Significant Unobservable Inputs Assets: Collateral dependent impaired loans $1,425 $— $— $1,425 Property acquired through foreclosure or repossession 131 — — 131 Total assets at fair value on a nonrecurring basis $1,556 $— $— $1,556 The allowance for loan losses on collateral dependent impaired loans amounted to $690 thousand at December 31, 2017 . The following tables present valuation techniques and unobservable inputs for assets measured at fair value on a nonrecurring basis for which the Corporation has utilized Level 3 inputs to determine fair value: (Dollars in thousands) Fair Value Valuation Technique Unobservable Input Range of Inputs Utilized (Weighted Average) September 30, 2018 Collateral dependent impaired loans $27 Appraisals of collateral Discount for costs to sell 0% - 10% (8%) Property acquired through foreclosure or repossession $2,974 Appraisals of collateral Discount for costs to sell 13% Appraisal adjustments (1) 12% (1) Management may adjust appraisal values to reflect market value declines or other discounts resulting from its knowledge of the property. (Dollars in thousands) Fair Value Valuation Technique Unobservable Input Range of Inputs Utilized (Weighted Average) December 31, 2017 Collateral dependent impaired loans $1,425 Appraisals of collateral Discount for costs to sell 0% - 15% (15%) Property acquired through foreclosure or repossession $131 Appraisals of collateral Discount for costs to sell 10% Appraisal adjustments (1) 12% - 17% (15%) (1) Management may adjust appraisal values to reflect market value declines or other discounts resulting from its knowledge of the property. Valuation of Other Financial Instruments The following tables present the carrying amount, estimated fair value and placement in the fair value hierarchy of the Corporation’s financial instruments. The tables exclude financial instruments for which the carrying value approximates fair value such as cash and cash equivalents, FHLB stock, accrued interest receivable, bank-owned life insurance, non-maturity deposits and accrued interest payable. (Dollars in thousands) September 30, 2018 Carrying Amount Total Fair Value Quoted Prices in Active Markets for Identical Assets Significant Other Observable Inputs Significant Unobservable Inputs Financial Assets: Securities held to maturity $10,863 $10,657 $— $10,657 $— Loans, net of allowance for loan losses 3,529,694 3,500,065 — — 3,500,065 Financial Liabilities: Time deposits $1,159,218 $1,170,151 $— $1,170,151 $— FHLB advances 828,392 827,328 — 827,328 — Junior subordinated debentures 22,681 19,844 — 19,844 — (Dollars in thousands) December 31, 2017 Carrying Amount Total Fair Value Quoted Prices in Active Markets for Identical Assets Significant Other Observable Inputs Significant Unobservable Inputs Financial Assets: Securities held to maturity $12,541 $12,721 $— $12,721 $— Loans, net of allowance for loan losses 3,347,583 3,369,932 — — 3,369,932 Financial Liabilities: Time deposits $1,015,095 $1,018,396 $— $1,018,396 $— FHLB advances 791,356 792,887 — 792,887 — Junior subordinated debentures 22,681 18,559 — 18,559 —

Revenue from Contracts with Cus

Revenue from Contracts with Customers	9 Months Ended
	Sep. 30, 2018
Revenue from Contract with Customer [Abstract]
Revenue from Contracts with Customers	Revenue from Contracts with Customers Overview Revenue from contracts with customers in the scope of Accounting Standards Codification (“ASC”) Topic 606 is measured based on the consideration specified in the contract with a customer. The Corporation recognizes revenue from contracts with customers when it satisfies its performance obligations. The Corporation’s performance obligations are generally satisfied as services are rendered and can either be satisfied at a point in time or over time. Unsatisfied performance obligations at the report date are not material to our unaudited consolidated financial statements. In certain cases, other parties are involved with providing services to our customers. If the Corporation is a principal in the transaction (providing services itself or through a third party on its behalf), revenues are reported based on the gross consideration received from the customer and any related expenses are reported gross in noninterest expense. If the Corporation is an agent in the transaction (referring customers to another party to provide services), the Corporation reports its net fee or commission retained as revenue. Accounting Policy Updates The Corporation adopted Topic 606 “Revenue from Contracts with Customers” effective January 1, 2018 and has applied the guidance to all contracts within the scope of Topic 606 as of that date. As a result, the Corporation has modified its accounting policy for revenue recognition as detailed herein. As discussed in Note 2 , the Corporation applied Topic 606 using the modified retrospective method, therefore, the prior period comparative information has not been adjusted and continues to be reported under Topic 605. There was no cumulative effect adjustment as of January 1, 2018, and there were no material changes to our unaudited consolidated financial statements at or for the nine months ended September 30, 2018 , as a result of adopting Topic 606. The Corporation applied the practical expedient pertaining to contracts with original expected duration of one year or less and does not disclose information about remaining performance obligations on such contracts. The Corporation also applied the practical expedient pertaining to contracts for which, at contract inception, the period between when the entity transfers the services and when the customer pays for those services will be one year or less. As such, the Corporation does not adjust the consideration from customers for the effects of a significant financing component. A substantial portion of the Corporation’s revenue is specifically excluded from the scope of Topic 606. For the revenue that is within scope of Topic 606, the following is a description of principal activities from which the Corporation generates its revenue from contracts with customers, separated by the timing of revenue recognition. Revenue Recognized at a Point in Time The Corporation recognizes revenue that is transactional in nature and such revenue is earned at a point in time. Revenue that is recognized at a point in time includes card interchange fees (fee income related to debit card transactions), ATM fees, wire transfer fees, overdraft charge fees, and stop-payment and returned check fees. Such revenue is derived from transactional information and is recognized as revenue immediately as the transactions occur or upon providing the service to complete the customer’s transaction. Revenue Recognized Over Time The Corporation recognizes revenue over a period of time, generally monthly, as services are performed and performance obligations are satisfied. Such revenue includes wealth management revenues and service charges on deposit accounts. Wealth management revenues are categorized as either asset-based revenues or transaction-based revenues. Asset-based revenues include trust and investment management fees that are earned based upon a percentage of asset values under administration. Transaction-based revenues include financial planning fees, tax preparation fees, commissions and other service fees. Fee revenue from service charges on deposit accounts represent the service charges assessed to customer who hold deposit accounts at the Bank. Costs of Obtaining Revenue from Contracts with Customers The Corporation pays commissions and incentives to its employees in accordance with certain employment arrangements and incentive plans. For commissions and incentives that are excluded from the scope of Topic 606, such as those paid to mortgage originator employees, the Corporation expenses these costs when incurred or applies the guidance in ASC Topic 310. For commissions and incentives that are in-scope of Topic 606, such as those paid to employees in our wealth management services and commercial banking segments in order to obtain customer contracts, contract cost assets are established. The contract cost assets are capitalized and amortized over the estimated useful life that the asset is expected to generate benefits. The amortization of the contract cost asset is recorded within salaries and employee benefits expense. Disaggregation of Revenue The following table summarizes total revenues as presented in the Unaudited Consolidated Statements of Income and the related amounts which are from contracts with customers within the scope of Topic 606. As shown below, a substantial portion of our revenues are specifically excluded from the scope of Topic 606. For the three month ended September 30, 2018 2017 (Dollars in thousands) As reported in Consolidated Statements of Income Revenue from contracts in scope of Topic 606 As reported in Consolidated Statements of Income Revenue from contracts in scope of Topic 606 Net interest income $33,449 $— $30,059 $— Noninterest income: Asset-based wealth management revenues 9,322 9,322 9,791 9,791 Transaction-based wealth management revenues 132 132 222 222 Total wealth management revenues 9,454 9,454 10,013 10,013 Mortgage banking revenues 2,624 — 3,036 — Service charges on deposit accounts 885 885 942 942 Card interchange fees 983 983 894 894 Income from bank-owned life insurance 572 — 546 — Loan related derivative income 278 — 1,452 — Other income 419 419 400 400 Total noninterest income 15,215 11,741 17,283 12,249 Total revenues $48,664 $11,741 $47,342 $12,249 For the nine months ended September 30, 2018 2017 (Dollars in thousands) As reported in Consolidated Statements of Income Revenue from contracts in scope of Topic 606 As reported in Consolidated Statements of Income Revenue from contracts in scope of Topic 606 Net interest income $98,412 $— $88,642 $— Noninterest income: Asset-based wealth management revenues 28,413 28,413 28,439 28,439 Transaction-based wealth management revenues 916 916 993 993 Total wealth management revenues 29,329 29,329 29,432 29,432 Mortgage banking revenues 8,403 — 8,295 — Service charges on deposit accounts 2,651 2,651 2,726 2,726 Card interchange fees 2,791 2,791 2,598 2,598 Income from bank-owned life insurance 1,624 — 1,624 — Loan related derivative income 1,087 — 2,744 — Other income 1,066 1,051 1,180 1,139 Total noninterest income 46,951 35,822 48,599 35,895 Total revenues $145,363 $35,822 $137,241 $35,895 The following table presents revenue from contracts with customers based on the timing of revenue recognition: (Dollars in thousands) Three Months Nine Months Periods ended September 30, 2018 2017 2018 2017 Revenue recognized at a point in time: Card interchange fees $983 $894 $2,791 $2,598 Service charges on deposit accounts 670 741 2,045 2,140 Other income 258 283 732 872 Revenue recognized over time: Wealth management revenues 9,454 10,013 29,329 29,432 Service charges on deposit accounts 215 201 606 586 Other income 161 117 319 267 Total revenues from contracts in scope of Topic 606 $11,741 $12,249 $35,822 $35,895 Receivables primarily consist of amounts due from customers for wealth management services performed for which the Corporation’s performance obligations have been fully satisfied. Receivables amounted to $5.2 million at September 30, 2018 , compared to $5.7 million at December 31, 2017 and were included in other assets in the Unaudited Consolidated Balance Sheets. Deferred revenues, which are considered contract liabilities under Topic 606, represent advance consideration received from customers for which the Corporation has a remaining performance obligation to fulfill. Contract liabilities are recognized as revenue over the life of the contract as the performance obligations are satisfied. The balances of contract liabilities were insignificant at both September 30, 2018 and December 31, 2017 and were included in other liabilities in the Unaudited Consolidated Balance Sheets. Contract cost assets (capitalized commission and incentive costs, net of amortization) at September 30, 2018 were insignificant and were included in other assets in the Unaudited Consolidated Balance Sheets.

Defined Benefit Pension Plans

Defined Benefit Pension Plans	9 Months Ended
	Sep. 30, 2018
Defined Benefit Plan [Abstract]
Defined Benefit Pension Plans	Defined Benefit Pension Plans The Corporation maintains a tax-qualified defined benefit pension plan for the benefit of certain eligible employees who were hired prior to October 1, 2007. The Corporation also has non-qualified retirement plans to provide supplemental retirement benefits to certain employees, as defined in the plans. The defined benefit pension plans were previously amended to freeze benefit accruals after a 10 -year transition period ending in December 2023. The defined benefit pension plan is funded on a current basis, in compliance with the requirements of ERISA. The non-qualified retirement plans provide for the designation of assets in rabbi trusts. Securities available for sale and other short-term investments designated for this purpose, with the carrying value of $12.5 million and $13.3 million are included in the Consolidated Balance Sheets at September 30, 2018 and December 31, 2017 , respectively. The composition of net periodic benefit cost was as follows: (Dollars in thousands) Qualified Pension Plan Non-Qualified Retirement Plans Three Months Nine Months Three Months Nine Months Periods ended September 30, 2018 2017 2018 2017 2018 2017 2018 2017 Net Periodic Benefit Cost: Service cost (1) $561 $537 $1,683 $1,611 $27 $32 $81 $97 Interest cost (2) 679 669 2,036 2,005 119 107 356 321 Expected return on plan assets (2) (1,318 ) (1,236 ) (3,954 ) (3,707 ) — — — — Amortization of prior service (credit) cost (2) (6 ) (6 ) (17 ) (17 ) — — — — Recognized net actuarial loss (2) 374 279 1,122 836 103 76 308 269 Net periodic benefit cost $290 $243 $870 $728 $249 $215 $745 $687 (1) Included in salaries and employee benefits expense in the Unaudited Consolidated Statements of Income. (2) Included in other expenses in the Unaudited Consolidated Statements of Income. The following table presents the measurement date and weighted-average assumptions used to determine net periodic benefit cost: Qualified Pension Plan Non-Qualified Retirement Plans For the nine months ended September 30, 2018 2017 2018 2017 Measurement date Dec 31, 2017 Dec 31, 2016 Dec 31, 2017 Dec 31, 2016 Equivalent single discount rate for benefit obligations 3.69% 4.18% 3.58% 3.96% Equivalent single discount rate for service cost 3.76 4.29 3.79 4.25 Equivalent single discount rate for interest cost 3.42 3.73 3.22 3.36 Expected long-term return on plan assets 6.75 6.75 N/A N/A Rate of compensation increase 3.75 3.75 3.75 3.75

Share-Based Compensation Arrang

Share-Based Compensation Arrangements	9 Months Ended
	Sep. 30, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Share-Based Compensation Arrangements	Share-Based Compensation Arrangements During the nine months ended September 30, 2018 , the Corporation granted equity awards, which included performance share awards and nonvested share unit awards. The performance share awards granted to certain executive officers provide them with the opportunity to earn shares of common stock of the Corporation. The performance share awards were valued at fair market value as of January 18, 2018 (the award date), or $54.25 , and will be earned over 3 - to 5 -year performance periods. The number of shares earned will range from zero to 200% of the target number of shares dependent upon the Corporation’s core return on equity and core earnings per share growth ranking compared to an industry peer group. The current assumption based on the most recent peer group information available results in shares earned at 140% of the target, or 41,454 shares. The Corporation granted to non-employee directors and a non-executive officer 6,830 nonvested share units, with 3 - to 5 -year cliff vesting. The weighted average grant date fair value of the nonvested share units was $56.65 .

Business Segments

Business Segments	9 Months Ended
	Sep. 30, 2018
Segment Reporting [Abstract]
Business Segments	Business Segments Washington Trust segregates financial information in assessing its results among its Commercial Banking and Wealth Management Services operating segments. The amounts in the Corporate unit include activity not related to the segments. Management uses certain methodologies to allocate income and expenses to the business lines. A funds transfer pricing (“FTP”) methodology is used to assign interest income and interest expense to each interest-earning asset and interest-bearing liability on a matched maturity funding basis. 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. Loans are assigned a FTP rate for funds used and deposits are assigned a FTP rate for funds provided. Certain indirect expenses are allocated to segments. These include support unit expenses such as technology, operations and other support functions. Commercial Banking The Commercial Banking segment includes commercial, residential and consumer lending activities; mortgage banking activities; deposit generation; cash management activities; and direct banking activities, which include the operation of ATMs, telephone and internet banking services and customer support and sales. Wealth Management Services Wealth Management Services includes investment management; financial planning; personal trust and estate services, including services as trustee, personal representative, custodian and guardian; and settlement of decedents’ estates. Institutional trust services are also provided, including fiduciary services. Corporate Corporate includes the Treasury Unit, which is responsible for managing the wholesale investment portfolio and wholesale funding needs. It also includes income from bank-owned life insurance (“BOLI”), as well as administrative and executive expenses not allocated to the operating segments and the residual impact of methodology allocations such as FTP offsets. The following table presents the statement of operations and total assets for Washington Trust’s reportable segments: (Dollars in thousands) Commercial Banking Wealth Management Services Corporate Consolidated Total Three months ended September 30, 2018 2017 2018 2017 2018 2017 2018 2017 Net interest income (expense) $27,036 $24,795 ($90 ) ($48 ) $6,503 $5,312 $33,449 $30,059 Provision for loan losses 350 1,300 — — — — 350 1,300 Net interest income (expense) after provision for loan losses 26,686 23,495 (90 ) (48 ) 6,503 5,312 33,099 28,759 Noninterest income 5,174 6,711 9,454 10,013 587 559 15,215 17,283 Noninterest expenses: Depreciation and amortization expense 654 646 371 411 44 50 1,069 1,107 Other noninterest expenses 15,599 15,834 6,194 6,810 3,200 3,003 24,993 25,647 Total noninterest expenses 16,253 16,480 6,565 7,221 3,244 3,053 26,062 26,754 Income before income taxes 15,607 13,726 2,799 2,744 3,846 2,818 22,252 19,288 Income tax expense 3,344 4,463 710 1,092 687 771 4,741 6,326 Net income $12,263 $9,263 $2,089 $1,652 $3,159 $2,047 $17,511 $12,962 Total assets at period end $3,694,991 $3,486,783 $69,494 $63,600 $1,006,187 $918,847 $4,770,672 $4,469,230 Expenditures for long-lived assets 612 890 14 25 19 22 645 937 (Dollars in thousands) Commercial Banking Wealth Management Services Corporate Consolidated Total Nine months ended September 30, 2018 2017 2018 2017 2018 2017 2018 2017 Net interest income (expense) $79,656 $72,985 ($225 ) ($120 ) $18,981 $15,777 $98,412 $88,642 Provision for loan losses 750 2,400 — — — — 750 2,400 Net interest income (expense) after provision for loan losses 78,906 70,585 (225 ) (120 ) 18,981 15,777 97,662 86,242 Noninterest income 15,947 17,500 29,329 29,432 1,675 1,667 46,951 48,599 Noninterest expenses: Depreciation and amortization expense 1,928 1,960 1,137 1,288 129 152 3,194 3,400 Other noninterest expenses 46,574 45,764 19,986 20,106 9,726 9,076 76,286 74,946 Total noninterest expenses 48,502 47,724 21,123 21,394 9,855 9,228 79,480 78,346 Income before income taxes 46,351 40,361 7,981 7,918 10,801 8,216 65,133 56,495 Income tax expense 9,834 13,142 2,008 3,172 1,895 2,238 13,737 18,552 Net income $36,517 $27,219 $5,973 $4,746 $8,906 $5,978 $51,396 $37,943 Total assets at period end $3,694,991 $3,486,783 $69,494 $63,600 $1,006,187 $918,847 $4,770,672 $4,469,230 Expenditures for long-lived assets 1,864 1,640 327 368 129 176 2,320 2,184

Other Comprehensive Income (Los

Other Comprehensive Income (Loss)	9 Months Ended
	Sep. 30, 2018
Equity [Abstract]
Other Comprehensive Income (Loss)	Other Comprehensive Income (Loss) The following tables present the activity in other comprehensive income (loss): Three months ended September 30, 2018 2017 (Dollars in thousands) Pre-tax Amounts Income Taxes Net of Tax Pre-tax Amounts Income Taxes Net of Tax Securities available for sale: Changes in fair value of securities available for sale ($5,924 ) ($1,393 ) ($4,531 ) $1,736 $642 $1,094 Net gains on securities reclassified into earnings — — — — — — Net change in fair value of securities available for sale (5,924 ) (1,393 ) (4,531 ) 1,736 642 1,094 Cash flow hedges: Change in fair value of cash flow hedges (626 ) (148 ) (478 ) (237 ) (83 ) (154 ) Net cash flow hedge losses reclassified into earnings (1) 830 197 633 224 83 141 Net change in fair value of cash flow hedges 204 49 155 (13 ) — (13 ) Defined benefit plan obligations: Defined benefit plan obligation adjustment — — — — — — Amortization of net actuarial losses (2) 477 112 365 355 134 221 Amortization of net prior service credits (2) (6 ) (2 ) (4 ) (6 ) (2 ) (4 ) Net change in defined benefit plan obligations 471 110 361 349 132 217 Total other comprehensive (loss) income ($5,249 ) ($1,234 ) ($4,015 ) $2,072 $774 $1,298 (1) The pre-tax amounts are included in interest expense on FHLB advances, interest expense on junior subordinated debentures and interest and fees on loans in the Unaudited Consolidated Statements of Income. (2) The pre-tax amounts are included in other expenses in the Unaudited Consolidated Statements of Income. Nine months ended September 30, 2018 2017 (Dollars in thousands) Pre-tax Amounts Income Taxes Net of Tax Pre-tax Amounts Income Taxes Net of Tax Securities available for sale: Changes in fair value of securities available for sale ($23,605 ) ($5,548 ) ($18,057 ) $5,274 $1,951 $3,323 Net gains on securities reclassified into earnings — — — — — — Net change in fair value of securities available for sale (23,605 ) (5,548 ) (18,057 ) 5,274 1,951 3,323 Cash flow hedges: Change in fair value of cash flow hedges 632 50 582 (1,064 ) (361 ) (703 ) Net cash flow hedge losses reclassified into earnings (1) 1,082 255 827 539 200 339 Net change in fair value of cash flow hedges 1,714 305 1,409 (525 ) (161 ) (364 ) Defined benefit plan obligations: Defined benefit plan obligation adjustment — — — (407 ) (150 ) (257 ) Amortization of net actuarial losses (2) 1,430 337 1,093 1,105 411 694 Amortization of net prior service credits (2) (17 ) (5 ) (12 ) (17 ) (7 ) (10 ) Net change in defined benefit plan obligations 1,413 332 1,081 681 254 427 Total other comprehensive (loss) income ($20,478 ) ($4,911 ) ($15,567 ) $5,430 $2,044 $3,386 (1) The pre-tax amounts are included in interest expense on FHLB advances, interest expense on junior subordinated debentures and interest and fees on loans in the Unaudited Consolidated Statements of Income. (2) The pre-tax amounts are included in other expenses in the Unaudited Consolidated Statements of Income. The following tables present the changes in accumulated other comprehensive income (loss) by component, net of tax: (Dollars in thousands) Net Unrealized Losses on Available For Sale Securities Net Unrealized (Losses) Gains on Cash Flow Hedges Pension Benefit Adjustment Total Balance at December 31, 2017 ($7,534 ) ($428 ) ($15,548 ) ($23,510 ) Other comprehensive (loss) income before reclassifications (18,057 ) 582 — (17,475 ) Amounts reclassified from accumulated other comprehensive income — 827 1,081 1,908 Net other comprehensive (loss) income (18,057 ) 1,409 1,081 (15,567 ) Balance at September 30, 2018 ($25,591 ) $981 ($14,467 ) ($39,077 ) (Dollars in thousands) Net Unrealized (Losses) Gains on Available For Sale Securities Net Unrealized Losses on Cash Flow Hedges Pension Benefit Adjustment Total Balance at December 31, 2016 ($6,825 ) ($300 ) ($12,632 ) ($19,757 ) Other comprehensive income (loss) before reclassifications 3,323 (703 ) — 2,620 Amounts reclassified from accumulated other comprehensive income — 339 427 766 Net other comprehensive income (loss) 3,323 (364 ) 427 3,386 Balance at September 30, 2017 ($3,502 ) ($664 ) ($12,205 ) ($16,371 )

Earnings Per Common Share

Earnings Per Common Share	9 Months Ended
	Sep. 30, 2018
Earnings Per Share [Abstract]
Earnings Per Common Share	Earnings Per Common Share The following table presents the calculation of earnings per common share: (Dollars and shares in thousands, except per share amounts) Three Months Nine Months Periods ended September 30, 2018 2017 2018 2017 Earnings per common share - basic: Net income $17,511 $12,962 $51,396 $37,943 Less dividends and undistributed earnings allocated to participating securities (36 ) (28 ) (112 ) (84 ) Net income applicable to common shareholders $17,475 $12,934 $51,284 $37,859 Weighted average common shares 17,283 17,212 17,263 17,201 Earnings per common share - basic $1.01 $0.75 $2.97 $2.20 Earnings per common share - diluted: Net income $17,511 $12,962 $51,396 $37,943 Less dividends and undistributed earnings allocated to participating securities (36 ) (28 ) (112 ) (84 ) Net income applicable to common shareholders $17,475 $12,934 $51,284 $37,859 Weighted average common shares 17,283 17,212 17,263 17,201 Dilutive effect of common stock equivalents 99 106 129 119 Weighted average diluted common shares 17,382 17,318 17,392 17,320 Earnings per common share - diluted $1.01 $0.75 $2.95 $2.19 Weighted average common stock equivalents, not included in common stock equivalents above because they were anti-dilutive, totaled 41,525 and 46,692 , respectively, for the three and nine months ended September 30, 2018 . There were no anti-dilutive weighted average common stock equivalents outstanding for the three and nine months ended September 30, 2017 .

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2018
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Financial Instruments with Off-Balance Sheet Risk The Corporation is a party to financial instruments with off-balance sheet risk in the normal course of business to meet the financing needs of its customers and to manage the Corporation’s exposure to fluctuations in interest rates. These financial instruments include commitments to extend credit, standby letters of credit, forward loan commitments, loan related derivative contracts and interest rate risk management contracts. These instruments involve, to varying degrees, elements of credit risk in excess of the amount recognized in the Corporation’s Unaudited Consolidated Balance Sheets. The contract or notional amounts of these instruments reflect the extent of involvement the Corporation has in particular classes of financial instruments. The Corporation’s credit policies with respect to interest rate swap agreements with commercial borrowers, commitments to extend credit and financial guarantees are similar to those used for loans. The interest rate swaps with other counterparties are generally subject to bilateral collateralization terms. The following table presents the contractual and notional amounts of financial instruments with off-balance sheet risk: (Dollars in thousands) Sep 30, Dec 31, Financial instruments whose contract amounts represent credit risk: Commitments to extend credit: Commercial loans $519,887 $537,310 Home equity lines 266,886 254,855 Other loans 44,665 48,819 Standby letters of credit 7,993 6,666 Financial instruments whose notional amounts exceed the amount of credit risk: Forward loan commitments: Interest rate lock commitments 38,612 45,139 Forward sale commitments 65,686 71,539 Loan related derivative contracts: Interest rate swaps with customers 574,364 545,049 Mirror swaps with counterparties 574,364 545,049 Risk participation-in agreements 36,610 34,052 Foreign exchange contracts 2,907 3,005 Interest rate risk management contracts: Interest rate swaps 60,000 60,000 See Note 9 for additional disclosure pertaining to derivative financial instruments. Commitments to Extend Credit Commitments to extend credit are agreements to lend to a customer as long as there are no violations of any condition established in the contract. Commitments generally have fixed expiration dates or other termination clauses and may require payment of a fee. Since some of the commitments are expected to expire without being drawn upon, total commitment amounts do not necessarily represent future cash requirements. Each borrower’s creditworthiness is evaluated on a case-by-case basis. The amount of collateral obtained is based on management’s credit evaluation of the borrower. Standby Letters of Credit Standby letters of credit are conditional commitments issued to guarantee the performance of a customer to a third party. These standby letters of credit are primarily issued to support the financing needs of the Bank’s commercial customers. The credit risk involved in issuing standby letters of credit is essentially the same as that involved in extending loan facilities to customers. The collateral supporting those commitments is essentially the same as for other commitments. Most standby letters of credit extend for one year. The maximum potential amount of undiscounted future payments, not reduced by amounts that may be recovered totaled $8.0 million and $6.7 million , as of September 30, 2018 and December 31, 2017 , respectfully. At September 30, 2018 and December 31, 2017 , there were no liabilities to beneficiaries resulting from standby letters of credit. Fee income on standby letters of credit was insignificant for the three and nine months ended September 30, 2018 and 2017 . Forward Loan Commitments Interest rate lock commitments are extended to borrowers and relate to the origination of residential real estate mortgage loans held for sale. To mitigate the interest rate risk and pricing risk associated with these rate locks and residential real estate mortgage loans held for sale, the Corporation enters into forward sale commitments. Both interest rate lock commitments and forward sale commitments are derivative financial instruments. Leases At September 30, 2018 , the Corporation was committed to rent premises used in business operations under non-cancelable operating leases. Rental expense under the operating leases amounted to $1.1 million and $3.2 million , respectively, for the three and nine months ended September 30, 2018 , compared to $1.1 million and $3.3 million , respectively, for the same periods in 2017 . The following table presents the minimum annual lease payments under the terms of these leases, exclusive of renewal provisions: (Dollars in thousands) October 1, 2018 to December 31, 2018 $933 2019 3,579 2020 2,860 2021 2,526 2022 2,133 2023 and thereafter 24,595 Total minimum lease payments $36,626 Lease expiration dates range from 8 months to 22 years, with additional renewal options on certain leases ranging from 1 to 5 years.

General Information (Policies)

General Information (Policies)	9 Months Ended
	Sep. 30, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Consolidation	The Unaudited Consolidated Financial Statements include the accounts of the Bancorp and its subsidiaries (collectively the “Corporation” or “Washington Trust”). All intercompany transactions have been eliminated.
Basis of Accounting	Certain previously reported amounts have been reclassified to conform to the current year’s presentation. The accounting and reporting policies of the Corporation conform to accounting principles generally accepted in the United States of America (“GAAP”) and to general practices of the banking industry.
Use of Estimates	In preparing the financial statements, management is required to make estimates and assumptions that affect the reported amounts of assets and liabilities as of the date of the balance sheet and revenues and expenses for the period. Actual results could differ from those estimates.

Revenue from Contracts with C_2

Revenue from Contracts with Customers (Policies)	9 Months Ended
	Sep. 30, 2018
Revenue from Contract with Customer [Abstract]
Revenue from Contracts with Customers	Accounting Policy Updates The Corporation adopted Topic 606 “Revenue from Contracts with Customers” effective January 1, 2018 and has applied the guidance to all contracts within the scope of Topic 606 as of that date. As a result, the Corporation has modified its accounting policy for revenue recognition as detailed herein. As discussed in Note 2 , the Corporation applied Topic 606 using the modified retrospective method, therefore, the prior period comparative information has not been adjusted and continues to be reported under Topic 605. There was no cumulative effect adjustment as of January 1, 2018, and there were no material changes to our unaudited consolidated financial statements at or for the nine months ended September 30, 2018 , as a result of adopting Topic 606. The Corporation applied the practical expedient pertaining to contracts with original expected duration of one year or less and does not disclose information about remaining performance obligations on such contracts. The Corporation also applied the practical expedient pertaining to contracts for which, at contract inception, the period between when the entity transfers the services and when the customer pays for those services will be one year or less. As such, the Corporation does not adjust the consideration from customers for the effects of a significant financing component. A substantial portion of the Corporation’s revenue is specifically excluded from the scope of Topic 606. For the revenue that is within scope of Topic 606, the following is a description of principal activities from which the Corporation generates its revenue from contracts with customers, separated by the timing of revenue recognition. Revenue Recognized at a Point in Time The Corporation recognizes revenue that is transactional in nature and such revenue is earned at a point in time. Revenue that is recognized at a point in time includes card interchange fees (fee income related to debit card transactions), ATM fees, wire transfer fees, overdraft charge fees, and stop-payment and returned check fees. Such revenue is derived from transactional information and is recognized as revenue immediately as the transactions occur or upon providing the service to complete the customer’s transaction. Revenue Recognized Over Time The Corporation recognizes revenue over a period of time, generally monthly, as services are performed and performance obligations are satisfied. Such revenue includes wealth management revenues and service charges on deposit accounts. Wealth management revenues are categorized as either asset-based revenues or transaction-based revenues. Asset-based revenues include trust and investment management fees that are earned based upon a percentage of asset values under administration. Transaction-based revenues include financial planning fees, tax preparation fees, commissions and other service fees. Fee revenue from service charges on deposit accounts represent the service charges assessed to customer who hold deposit accounts at the Bank. Costs of Obtaining Revenue from Contracts with Customers The Corporation pays commissions and incentives to its employees in accordance with certain employment arrangements and incentive plans. For commissions and incentives that are excluded from the scope of Topic 606, such as those paid to mortgage originator employees, the Corporation expenses these costs when incurred or applies the guidance in ASC Topic 310. For commissions and incentives that are in-scope of Topic 606, such as those paid to employees in our wealth management services and commercial banking segments in order to obtain customer contracts, contract cost assets are established. The contract cost assets are capitalized and amortized over the estimated useful life that the asset is expected to generate benefits. The amortization of the contract cost asset is recorded within salaries and employee benefits expense.

Securities (Tables)

Securities (Tables)	9 Months Ended
	Sep. 30, 2018
Investments, Debt and Equity Securities [Abstract]
Summary of Investments	The following tables present the amortized cost, gross unrealized holding gains, gross unrealized holding losses and fair value of securities by major security type and class of security: (Dollars in thousands) September 30, 2018 Amortized Cost Unrealized Gains Unrealized Losses Fair Value Securities Available for Sale: Obligations of U.S. government-sponsored enterprises $201,398 $9 ($7,934 ) $193,473 Mortgage-backed securities issued by U.S. government agencies and U.S. government-sponsored enterprises 616,552 1,143 (24,833 ) 592,862 Obligations of states and political subdivisions 935 2 — 937 Individual name issuer trust preferred debt securities 13,303 — (839 ) 12,464 Corporate bonds 13,911 — (1,000 ) 12,911 Total securities available for sale $846,099 $1,154 ($34,606 ) $812,647 Held to Maturity: Mortgage-backed securities issued by U.S. government agencies and U.S. government-sponsored enterprises $10,863 $— ($206 ) $10,657 Total securities held to maturity $10,863 $— ($206 ) $10,657 Total securities $856,962 $1,154 ($34,812 ) $823,304 (Dollars in thousands) December 31, 2017 Amortized Cost Unrealized Gains Unrealized Losses Fair Value Securities Available for Sale: Obligations of U.S. government-sponsored enterprises $161,479 $— ($3,875 ) $157,604 Mortgage-backed securities issued by U.S. government agencies and U.S. government-sponsored enterprises 594,944 3,671 (7,733 ) 590,882 Obligations of states and political subdivisions 2,355 4 — 2,359 Individual name issuer trust preferred debt securities 18,106 — (1,122 ) 16,984 Corporate bonds 13,917 13 (805 ) 13,125 Total securities available for sale $790,801 $3,688 ($13,535 ) $780,954 Held to Maturity: Mortgage-backed securities issued by U.S. government agencies and U.S. government-sponsored enterprises $12,541 $180 $— $12,721 Total securities held to maturity $12,541 $180 $— $12,721 Total securities $803,342 $3,868 ($13,535 ) $793,675
Securities by Contractual Maturity	The schedule of maturities of debt securities available for sale and held to maturity is presented below. Mortgage-backed securities are included based on weighted average maturities, adjusted for anticipated prepayments. All other debt securities are included based on contractual maturities. Actual maturities may differ from amounts presented because certain issuers have the right to call or prepay obligations with or without call or prepayment penalties. (Dollars in thousands) Available for Sale Held to Maturity September 30, 2018 Amortized Cost Fair Value Amortized Cost Fair Value Due in one year or less $64,023 $61,577 $1,370 $1,344 Due after one year to five years 314,353 302,124 4,529 4,443 Due after five years to ten years 278,106 266,878 3,709 3,639 Due after ten years 189,617 182,068 1,255 1,231 Total securities $846,099 $812,647 $10,863 $10,657
Securities in a Continuous Unrealized Loss Position	The following tables summarize temporarily impaired securities, segregated by length of time the securities have been in a continuous unrealized loss position: (Dollars in thousands) Less than 12 Months 12 Months or Longer Total September 30, 2018 # Fair Unrealized # Fair Value Unrealized Losses # Fair Value Unrealized Losses Obligations of U.S. government-sponsored enterprises 8 $77,958 ($2,040 ) 11 $105,606 ($5,894 ) 19 $183,564 ($7,934 ) Mortgage-backed securities issued by U.S. government agencies and U.S. government-sponsored enterprises 37 235,900 (6,567 ) 34 304,937 (18,472 ) 71 540,837 (25,039 ) Individual name issuer trust preferred debt securities — — — 5 12,464 (839 ) 5 12,464 (839 ) Corporate bonds 4 1,706 (13 ) 5 11,205 (987 ) 9 12,911 (1,000 ) Total temporarily impaired securities 49 $315,564 ($8,620 ) 55 $434,212 ($26,192 ) 104 $749,776 ($34,812 ) (Dollars in thousands) Less than 12 Months 12 Months or Longer Total December 31, 2017 # Fair Value Unrealized Losses # Fair Value Unrealized Losses # Fair Value Unrealized Losses Obligations of U.S. government-sponsored enterprises 8 $69,681 ($798 ) 8 $87,923 ($3,077 ) 16 $157,604 ($3,875 ) Mortgage-backed securities issued by U.S. government agencies and U.S. government-sponsored enterprises 20 128,965 (613 ) 22 279,693 (7,120 ) 42 408,658 (7,733 ) Individual name issuer trust preferred debt securities — — — 7 16,984 (1,122 ) 7 16,984 (1,122 ) Corporate bonds 3 921 (5 ) 3 10,980 (800 ) 6 11,901 (805 ) Total temporarily impaired securities 31 $199,567 ($1,416 ) 40 $395,580 ($12,119 ) 71 $595,147 ($13,535 )

Loans (Tables)

Loans (Tables)	9 Months Ended
	Sep. 30, 2018
Receivables [Abstract]
Summary of Loans	The following is a summary of loans: (Dollars in thousands) September 30, 2018 December 31, 2017 Amount % Amount % Commercial: Commercial real estate (1) $1,240,350 35 % $1,210,495 36 % Commercial & industrial (2) 656,882 18 612,334 18 Total commercial 1,897,232 53 1,822,829 54 Residential Real Estate: Residential real estate (3) 1,349,340 38 1,227,248 36 Consumer: Home equity 282,331 8 292,467 9 Other (4) 27,300 1 31,527 1 Total consumer 309,631 9 323,994 10 Total loans (5) $3,556,203 100 % $3,374,071 100 % (1) Commercial real estate loans consist of commercial mortgages primarily secured by income producing property, as well as construction and development loans. Construction and development loans are made to businesses for land development or the on-site construction of industrial, commercial, or residential buildings. (2) Commercial & industrial consist of loans to businesses and individuals, a substantial portion of which are fully or partially collateralized by real estate. (3) Residential real estate loans consist of mortgage and homeowner construction loans secured by one- to four- family residential properties. (4) Other consumer loans consists of loans to individuals secured by general aviation aircraft and other personal installment loans. (5) Includes net unamortized loan origination costs of $4.8 million and $3.8 million , respectively, at September 30, 2018 and December 31, 2017 and net unamortized premiums on purchased loans of $746 thousand and $878 thousand , respectively, at September 30, 2018 and December 31, 2017 .
Past Due Loans	The following tables present an age analysis of past due loans, segregated by class of loans: (Dollars in thousands) Days Past Due September 30, 2018 30-59 60-89 Over 90 Total Past Due Current Total Loans Commercial: Commercial real estate $— $931 $— $931 $1,239,419 $1,240,350 Commercial & industrial — 20 122 142 656,740 656,882 Total commercial — 951 122 1,073 1,896,159 1,897,232 Residential Real Estate: Residential real estate 5,322 2,936 1,140 9,398 1,339,942 1,349,340 Consumer: Home equity 1,854 534 551 2,939 279,392 282,331 Other 109 — — 109 27,191 27,300 Total consumer 1,963 534 551 3,048 306,583 309,631 Total loans $7,285 $4,421 $1,813 $13,519 $3,542,684 $3,556,203 (Dollars in thousands) Days Past Due December 31, 2017 30-59 60-89 Over 90 Total Past Due Current Total Loans Commercial: Commercial real estate $6 $— $4,954 $4,960 $1,205,535 $1,210,495 Commercial & industrial 3,793 2 281 4,076 608,258 612,334 Total commercial 3,799 2 5,235 9,036 1,813,793 1,822,829 Residential Real Estate: Residential real estate 1,678 2,274 3,903 7,855 1,219,393 1,227,248 Consumer: Home equity 2,798 75 268 3,141 289,326 292,467 Other 29 — 14 43 31,484 31,527 Total consumer 2,827 75 282 3,184 320,810 323,994 Total loans $8,304 $2,351 $9,420 $20,075 $3,353,996 $3,374,071
Impaired Loans	The following is a summary of impaired loans: (Dollars in thousands) Recorded Investment (1) Unpaid Principal Related Allowance Sep 30, Dec 31, Sep 30, Dec 31, Sep 30, Dec 31, No Related Allowance Recorded Commercial: Commercial real estate $— $— $— $— $— $— Commercial & industrial 4,825 4,986 4,877 5,081 — — Total commercial 4,825 4,986 4,877 5,081 — — Residential Real Estate: Residential real estate 8,737 9,069 8,896 9,256 — — Consumer: Home equity 1,582 557 1,583 557 — — Other — 14 — 14 — — Total consumer 1,582 571 1,583 571 — — Subtotal 15,144 14,626 15,356 14,908 — — With Related Allowance Recorded Commercial: Commercial real estate $— $4,954 $— $9,910 $— $1,018 Commercial & industrial 54 191 75 212 — 1 Total commercial 54 5,145 75 10,122 — 1,019 Residential Real Estate: Residential real estate 692 715 722 741 101 104 Consumer: Home equity 52 — 51 — 8 — Other 23 133 23 132 3 6 Total consumer 75 133 74 132 11 6 Subtotal 821 5,993 871 10,995 112 1,129 Total impaired loans $15,965 $20,619 $16,227 $25,903 $112 $1,129 Total: Commercial $4,879 $10,131 $4,952 $15,203 $— $1,019 Residential real estate 9,429 9,784 9,618 9,997 101 104 Consumer 1,657 704 1,657 703 11 6 Total impaired loans $15,965 $20,619 $16,227 $25,903 $112 $1,129 (1) The recorded investment in impaired loans consists of unpaid principal balance, net of charge-offs, interest payments received applied to principal and unamortized deferred loan origination fees and costs. For accruing impaired loans (troubled debt restructurings for which management has concluded that the collectibility of the loan is not in doubt), the recorded investment also includes accrued interest. The following tables present the average recorded investment balance of impaired loans and interest income recognized on impaired loans segregated by loan class. (Dollars in thousands) Average Recorded Investment Interest Income Recognized Three months ended September 30, 2018 2017 2018 2017 Commercial: Commercial real estate $— $8,041 $— $21 Commercial & industrial 5,324 6,427 62 67 Total commercial 5,324 14,468 62 88 Residential Real Estate: Residential real estate 9,265 15,107 96 102 Consumer: Home equity 1,424 543 22 5 Other 25 142 — 2 Total consumer 1,449 685 22 7 Totals $16,038 $30,260 $180 $197 (Dollars in thousands) Average Recorded Investment Interest Income Recognized Nine months ended September 30, 2018 2017 2018 2017 Commercial: Commercial real estate $1,352 $9,117 $— $73 Commercial & industrial 5,599 6,750 201 219 Total commercial 6,951 15,867 201 292 Residential Real Estate: Residential real estate 9,709 15,750 293 374 Consumer: Home equity 1,045 734 41 25 Other 85 142 5 8 Total consumer 1,130 876 46 33 Totals $17,790 $32,493 $540 $699
Nonaccrual Loans	The following is a summary of nonaccrual loans, segregated by class of loans: (Dollars in thousands) Sep 30, Dec 31, Commercial: Commercial real estate $— $4,954 Commercial & industrial 122 283 Total commercial 122 5,237 Residential Real Estate: Residential real estate 9,063 9,414 Consumer: Home equity 1,624 544 Other — 16 Total consumer 1,624 560 Total nonaccrual loans $10,809 $15,211 Accruing loans 90 days or more past due $— $—
Credit Quality Indicators Commercial	The following table presents the commercial loan portfolio, segregated by category of credit quality indicator: (Dollars in thousands) Pass Special Mention Classified Sep 30, Dec 31, Sep 30, Dec 31, Sep 30, Dec 31, Commercial: Commercial real estate 1,235,579 1,205,381 1,065 — 3,706 5,114 Commercial & industrial 593,673 592,749 55,012 9,804 8,197 9,781 Total commercial $1,829,252 $1,798,130 $56,077 $9,804 $11,903 $14,895
Credit Quality Indicators Residential & Consumer	The following table presents the residential and consumer loan portfolios, segregated by loan type and credit quality indicator: (Dollars in thousands) Current Past Due Sep 30, Dec 31, Sep 30, Dec 31, Residential Real Estate: Self-originated mortgages $1,224,575 $1,091,291 $8,172 $6,413 Purchased mortgages 115,367 128,102 1,226 1,442 Total residential real estate $1,339,942 $1,219,393 $9,398 $7,855 Consumer: Home equity $279,392 $289,326 $2,939 $3,141 Other 27,191 31,484 109 43 Total consumer $306,583 $320,810 $3,048 $3,184

Allowance for Loan Losses (Tabl

Allowance for Loan Losses (Tables)	9 Months Ended
	Sep. 30, 2018
Receivables [Abstract]
Allowance for Loan Losses Rollforward Analysis	The following table presents the activity in the allowance for loan losses for the three months ended September 30, 2018 : (Dollars in thousands) Commercial Consumer CRE (1) C&I (2) Total Commercial Residential Real Estate Home Equity Other Total Consumer Total Beginning Balance $12,443 $6,642 $19,085 $5,314 $1,375 $400 $1,775 $26,174 Charge-offs — (1 ) (1 ) (68 ) — (27 ) (27 ) (96 ) Recoveries — 71 71 — 2 8 10 81 Provision 1,052 535 1,587 (1,131 ) 12 (118 ) (106 ) 350 Ending Balance $13,495 $7,247 $20,742 $4,115 $1,389 $263 $1,652 $26,509 (1) Commercial real estate loans. (2) Commercial & industrial loans. The following table presents the activity in the allowance for loan losses for the nine months ended September 30, 2018 : (Dollars in thousands) Commercial Consumer CRE (1) C&I (2) Total Commercial Residential Real Estate Home Equity Other Total Consumer Total Beginning Balance $12,729 $5,580 $18,309 $5,427 $2,412 $340 $2,752 $26,488 Charge-offs (627 ) (8 ) (635 ) (73 ) (111 ) (70 ) (181 ) (889 ) Recoveries 25 104 129 — 12 19 31 160 Provision 1,368 1,571 2,939 (1,239 ) (924 ) (26 ) (950 ) 750 Ending Balance $13,495 $7,247 $20,742 $4,115 $1,389 $263 $1,652 $26,509 (1) Commercial real estate loans. (2) Commercial & industrial loans. The following table presents the activity in the allowance for loan losses for the three months ended September 30, 2017 : (Dollars in thousands) Commercial Consumer CRE (1) C&I (2) Total Commercial Residential Real Estate Home Equity Other Total Consumer Total Beginning Balance $11,935 $7,067 $19,002 $5,369 $1,927 $364 $2,291 $26,662 Charge-offs (535 ) (122 ) (657 ) — (18 ) (19 ) (37 ) (694 ) Recoveries — 8 8 1 25 6 31 40 Provision 1,387 (301 ) 1,086 70 (27 ) 171 144 1,300 Ending Balance $12,787 $6,652 $19,439 $5,440 $1,907 $522 $2,429 $27,308 (1) Commercial real estate loans. (2) Commercial & industrial loans. The following table presents the activity in the allowance for loan losses for the nine months ended September 30, 2017 : (Dollars in thousands) Commercial Consumer CRE (1) C&I (2) Total Commercial Residential Real Estate Home Equity Other Total Consumer Total Beginning Balance $11,166 $6,992 $18,158 $5,252 $1,889 $705 $2,594 $26,004 Charge-offs (935 ) (286 ) (1,221 ) (32 ) (79 ) (83 ) (162 ) (1,415 ) Recoveries 82 162 244 29 31 15 46 319 Provision 2,474 (216 ) 2,258 191 66 (115 ) (49 ) 2,400 Ending Balance $12,787 $6,652 $19,439 $5,440 $1,907 $522 $2,429 $27,308 (1) Commercial real estate loans. (2) Commercial & industrial loans.
Schedule of Allowance for Loan Loss by Segment & Impairment Methodology	The following table presents the Corporation’s loan portfolio and associated allowance for loan loss by portfolio segment and by impairment methodology: (Dollars in thousands) September 30, 2018 December 31, 2017 Loans Related Allowance Loans Related Allowance Loans Individually Evaluated for Impairment Commercial: Commercial real estate $— $— $4,954 $1,018 Commercial & industrial 4,860 — 5,157 1 Total commercial 4,860 — 10,111 1,019 Residential Real Estate: Residential real estate 9,428 101 9,783 104 Consumer: Home equity 1,635 9 557 — Other 22 2 147 6 Total consumer 1,657 11 704 6 Subtotal 15,945 112 20,598 1,129 Loans Collectively Evaluated for Impairment Commercial: Commercial real estate 1,240,350 13,495 1,205,541 11,711 Commercial & industrial 652,022 7,247 607,177 5,579 Total commercial 1,892,372 20,742 1,812,718 17,290 Residential Real Estate: Residential real estate 1,339,912 4,014 1,217,465 5,323 Consumer: Home equity 280,696 1,380 291,910 2,412 Other 27,278 261 31,380 334 Total consumer 307,974 1,641 323,290 2,746 Subtotal 3,540,258 26,397 3,353,473 25,359 Total $3,556,203 $26,509 $3,374,071 $26,488

Borrowings (Tables)

Borrowings (Tables)	9 Months Ended
	Sep. 30, 2018
Debt Disclosure [Abstract]
Federal Home Loan Bank Advances Maturities	The following table presents maturities and weighted average interest rates on FHLB advances outstanding as of September 30, 2018 : (Dollars in thousands) Total Outstanding Weighted Average Rate October 1, 2018 to December 31, 2018 $297,670 2.26 % 2019 347,258 2.15 2020 67,033 1.95 2021 46,222 2.57 2022 55,447 3.59 2023 and thereafter 14,762 2.29 Balance at September 30, 2018 $828,392 2.35 %

Shareholders' Equity (Tables)

Shareholders' Equity (Tables)	9 Months Ended
	Sep. 30, 2018
Regulatory Capital Requirements [Abstract]
Regulatory Capital Requirements	The following table presents the Corporation’s and the Bank’s actual capital amounts and ratios, as well as the corresponding minimum and well capitalized regulatory amounts and ratios that were in effect during the respective periods: (Dollars in thousands) Actual For Capital Adequacy Purposes To Be “Well Capitalized” Under Prompt Corrective Action Provisions Amount Ratio Amount Ratio Amount Ratio September 30, 2018 Total Capital (to Risk-Weighted Assets): Corporation $445,448 12.77 % $279,165 8.00 % N/A N/A Bank 442,337 12.68 279,145 8.00 $348,931 10.00 % Tier 1 Capital (to Risk-Weighted Assets): Corporation 418,649 12.00 209,374 6.00 N/A N/A Bank 415,538 11.91 209,358 6.00 279,145 8.00 Common Equity Tier 1 Capital (to Risk-Weighted Assets): Corporation 396,651 11.37 157,031 4.50 N/A N/A Bank 415,538 11.91 157,019 4.50 226,805 6.50 Tier 1 Capital (to Average Assets): (1) Corporation 418,649 8.91 187,898 4.00 N/A N/A Bank 415,538 8.85 187,858 4.00 234,822 5.00 December 31, 2017 Total Capital (to Risk-Weighted Assets): Corporation 416,038 12.45 267,365 8.00 N/A N/A Bank 413,593 12.38 267,338 8.00 334,172 10.00 Tier 1 Capital (to Risk-Weighted Assets): Corporation 389,289 11.65 200,524 6.00 N/A N/A Bank 386,844 11.58 200,503 6.00 267,338 8.00 Common Equity Tier 1 Capital (to Risk-Weighted Assets): Corporation 367,291 10.99 150,383 4.50 N/A N/A Bank 386,844 11.58 150,378 4.50 217,212 6.50 Tier 1 Capital (to Average Assets): (1) Corporation 389,289 8.79 177,089 4.00 N/A N/A Bank 386,844 8.74 177,048 4.00 221,310 5.00 (1) Leverage ratio.

Derivative Financial Instrume_2

Derivative Financial Instruments (Tables)	9 Months Ended
	Sep. 30, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Fair Value of Derivatives by Balance Sheet Location	The following table presents the fair values of derivative instruments in the Corporation’s Unaudited Consolidated Balance Sheets: (Dollars in thousands) Asset Derivatives Liability Derivatives Fair Value Fair Value Balance Sheet Location Sep 30, 2018 Dec 31, 2017 Balance Sheet Location Sep 30, 2018 Dec 31, 2017 Derivatives Designated as Cash Flow Hedging Instruments: Interest rate risk management contracts: Interest rate caps Other assets $83 $25 Other liabilities $— $— Interest rate swaps Other assets 1,947 213 Other liabilities — 14 Interest rate floors Other assets 14 110 Other liabilities — — Derivatives not Designated as Hedging Instruments: Loan related derivative contracts: Interest rate swaps with customers Other assets 33 268 Other liabilities 17,522 1,295 Mirror swaps with counterparties Other assets 17,342 1,152 Other liabilities 33 268 Risk participation agreements Other assets — — Other liabilities — — Foreign exchange contracts Other assets 37 — Other liabilities — 26 Forward loan commitments: Interest rate lock commitments Other assets 618 965 Other liabilities 1 20 Forward sale commitments Other assets 168 26 Other liabilities 266 1,424 Total $20,242 $2,759 $17,822 $3,047
Derivative Instruments Effect in Statements of Income and Changes in Shareholders' Equity	The following tables present the effect of derivative instruments in the Corporation’s Unaudited Consolidated Statements of Changes in Shareholders’ Equity and Unaudited Consolidated Statements of Income: (Dollars in thousands) Gain (Loss) Recognized in Other Comprehensive Income, Net of Tax (Effective Portion) Three Months Nine Months Periods ended September 30, 2018 2017 2018 2017 Derivatives Designated as Cash Flow Hedging Instruments: Interest rate risk management contracts: Interest rate caps $17 ($7 ) $66 ($64 ) Interest rate swaps 189 74 1,322 (26 ) Interest rate floors (51 ) (80 ) 21 (274 ) Total $155 ($13 ) $1,409 ($364 ) (Dollars in thousands) Amount of Gain (Loss) Recognized in Income on Derivatives Three Months Nine Months Periods ended September 30, Statement of Income Location 2018 2017 2018 2017 Derivatives not Designated as Hedging Instruments: Loan related derivative contracts: Interest rate swaps with customers Loan related derivative income ($3,178 ) $1,917 (15,374 ) 5,583 Mirror swaps with counterparties Loan related derivative income 3,415 (505 ) 16,384 (2,578 ) Risk participation agreements Loan related derivative income 25 40 25 (261 ) Foreign exchange contracts Loan related derivative income 16 — 52 — Forward loan commitments: Interest rate lock commitments Mortgage banking revenues (504 ) 32 ($327 ) $639 Forward sale commitments Mortgage banking revenues 316 59 1,552 (1,321 ) Total $90 $1,543 $2,312 $2,062

Balance Sheet Offsetting (Table

Balance Sheet Offsetting (Tables)	9 Months Ended
	Sep. 30, 2018
Balance Sheet Offsetting [Abstract]
Balance Sheet Offsetting	The following tables present the Corporation’s derivative asset and derivative liability positions and the effect of netting arrangements on the Unaudited Consolidated Balance Sheets: (Dollars in thousands) Gross Derivative Positions Offsetting Derivative Positions Net Amounts Presented in Balance Sheet Cash Collateral Pledged Net Amount September 30, 2018 Derivative Assets: Interest rate risk management contracts: Interest rate caps $83 $— $83 $— $83 Interest rate swaps 1,947 — 1,947 — 1,947 Interest rate floors 14 — 14 — 14 Loan-related derivative contracts: Interest rate swaps with customers 463 430 33 — 33 Mirror swaps with counterparties 17,784 442 17,342 — 17,342 Foreign exchange contracts 37 — 37 — 37 Total $20,328 $872 $19,456 $— $19,456 Derivative Liabilities: Loan-related derivative contracts: Interest rate swaps with customers $17,952 $430 $17,522 $— $17,522 Mirror swaps with counterparties 475 442 33 — 33 Total $18,427 $872 $17,555 $— $17,555 (Dollars in thousands) Gross Derivative Positions Offsetting Derivative Positions Net Amounts Presented in Balance Sheet Cash Collateral Pledged Net Amount December 31, 2017 Derivative Assets: Interest rate risk management contracts: Interest rate caps $25 $— $25 $— $25 Interest rate swaps 213 — 213 — 213 Interest rate floors 110 — 110 — 110 Loan-related derivative contracts: Interest rate swaps with customers 2,857 2,589 268 — 268 Mirror swaps with counterparties 3,801 2,649 1,152 — 1,152 Total $7,006 $5,238 $1,768 $— $1,768 Derivative Liabilities: Interest rate risk management contracts: Interest rate swaps $14 $— $14 $14 $— Loan-related derivative contracts: Interest rate swaps with customers 3,884 2,589 1,295 1,025 270 Mirror swaps with counterparties 2,917 2,649 268 — 268 Foreign exchange contracts 26 — 26 — 26 Total $6,841 $5,238 $1,603 $1,039 $564

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2018
Fair Value Disclosures [Abstract]
Items Recorded at Fair Value on a Recurring Basis	The following tables present the balances of assets and liabilities reported at fair value on a recurring basis: (Dollars in thousands) Total Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) September 30, 2018 Assets: Securities available for sale: Obligations of U.S. government-sponsored enterprises $193,473 $— $193,473 $— Mortgage-backed securities issued by U.S. government agencies and U.S. government-sponsored enterprises 592,862 — 592,862 — Obligations of states and political subdivisions 937 — 937 — Individual name issuer trust preferred debt securities 12,464 — 12,464 — Corporate bonds 12,911 — 12,911 — Mortgage loans held for sale 22,571 — 22,571 — Derivative assets 20,242 — 20,242 — Total assets at fair value on a recurring basis $855,460 $— $855,460 $— Liabilities: Derivative liabilities $17,822 $— $17,822 $— Contingent consideration liability 187 — — 187 Total liabilities at fair value on a recurring basis $18,009 $— $17,822 $187 (Dollars in thousands) Total Quoted Prices in Active Markets for Identical Assets Significant Other Observable Inputs Significant Unobservable Inputs December 31, 2017 Assets: Securities available for sale: Obligations of U.S. government-sponsored enterprises $157,604 $— $157,604 $— Mortgage-backed securities issued by U.S. government agencies and U.S. government-sponsored enterprises 590,882 — 590,882 — Obligations of states and political subdivisions 2,359 — 2,359 — Individual name issuer trust preferred debt securities 16,984 — 16,984 — Corporate bonds 13,125 — 13,125 — Mortgage loans held for sale 26,943 — 26,943 — Derivative assets 2,759 — 2,759 — Total assets at fair value on a recurring basis $810,656 $— $810,656 $— Liabilities: Derivative liabilities $3,047 $— $3,047 $— Contingent consideration liability 1,404 — — 1,404 Total liabilities at fair value on a recurring basis $4,451 $— $3,047 $1,404
Change in Contingent Consideration Liability	The following table presents the change in the contingent consideration liability, which is included in other liabilities in the Unaudited Consolidated Balance Sheets. (Dollars in thousands) Three Months Nine Months Periods ended September 30, 2018 2017 2018 2017 Balance at beginning of period $187 $1,737 $1,404 $2,047 Change in fair value — — — (310 ) Payments — — (1,217 ) — Balance at end of period $187 $1,737 $187 $1,737
Items Recorded at Fair Value on a Nonrecurring Basis	The following table presents the carrying value of assets held at September 30, 2018 , which were written down to fair value during the nine months ended September 30, 2018 : (Dollars in thousands) Total Quoted Prices in Active Markets for Identical Assets Significant Other Observable Inputs Significant Unobservable Inputs Assets: Collateral dependent impaired loans $27 $— $— $27 Property acquired through foreclosure or repossession 2,974 — — 2,974 Total assets at fair value on a nonrecurring basis $3,001 $— $— $3,001 The allowance for loan losses on collateral dependent impaired loans amounted to $8 thousand at September 30, 2018 . The following table presents the carrying value of assets held at December 31, 2017 , which were written down to fair value during the year ended December 31, 2017 : (Dollars in thousands) Total Quoted Prices in Active Markets for Identical Assets Significant Other Observable Inputs Significant Unobservable Inputs Assets: Collateral dependent impaired loans $1,425 $— $— $1,425 Property acquired through foreclosure or repossession 131 — — 131 Total assets at fair value on a nonrecurring basis $1,556 $— $— $1,556 The allowance for loan losses on collateral dependent impaired loans amounted to $690 thousand at December 31, 2017 .
Quantitative Information About Level 3 Assets Measured at Fair Value on a Nonrecurring Basis	The following tables present valuation techniques and unobservable inputs for assets measured at fair value on a nonrecurring basis for which the Corporation has utilized Level 3 inputs to determine fair value: (Dollars in thousands) Fair Value Valuation Technique Unobservable Input Range of Inputs Utilized (Weighted Average) September 30, 2018 Collateral dependent impaired loans $27 Appraisals of collateral Discount for costs to sell 0% - 10% (8%) Property acquired through foreclosure or repossession $2,974 Appraisals of collateral Discount for costs to sell 13% Appraisal adjustments (1) 12% (1) Management may adjust appraisal values to reflect market value declines or other discounts resulting from its knowledge of the property. (Dollars in thousands) Fair Value Valuation Technique Unobservable Input Range of Inputs Utilized (Weighted Average) December 31, 2017 Collateral dependent impaired loans $1,425 Appraisals of collateral Discount for costs to sell 0% - 15% (15%) Property acquired through foreclosure or repossession $131 Appraisals of collateral Discount for costs to sell 10% Appraisal adjustments (1) 12% - 17% (15%) (1) Management may adjust appraisal values to reflect market value declines or other discounts resulting from its knowledge of the property.
Carrying Amounts and Estimated Fair Values of Financial Instruments	The following tables present the carrying amount, estimated fair value and placement in the fair value hierarchy of the Corporation’s financial instruments. The tables exclude financial instruments for which the carrying value approximates fair value such as cash and cash equivalents, FHLB stock, accrued interest receivable, bank-owned life insurance, non-maturity deposits and accrued interest payable. (Dollars in thousands) September 30, 2018 Carrying Amount Total Fair Value Quoted Prices in Active Markets for Identical Assets Significant Other Observable Inputs Significant Unobservable Inputs Financial Assets: Securities held to maturity $10,863 $10,657 $— $10,657 $— Loans, net of allowance for loan losses 3,529,694 3,500,065 — — 3,500,065 Financial Liabilities: Time deposits $1,159,218 $1,170,151 $— $1,170,151 $— FHLB advances 828,392 827,328 — 827,328 — Junior subordinated debentures 22,681 19,844 — 19,844 — (Dollars in thousands) December 31, 2017 Carrying Amount Total Fair Value Quoted Prices in Active Markets for Identical Assets Significant Other Observable Inputs Significant Unobservable Inputs Financial Assets: Securities held to maturity $12,541 $12,721 $— $12,721 $— Loans, net of allowance for loan losses 3,347,583 3,369,932 — — 3,369,932 Financial Liabilities: Time deposits $1,015,095 $1,018,396 $— $1,018,396 $— FHLB advances 791,356 792,887 — 792,887 — Junior subordinated debentures 22,681 18,559 — 18,559 —

Revenue from Contracts with C_3

Revenue from Contracts with Customers (Tables)	9 Months Ended
	Sep. 30, 2018
Revenue from Contract with Customer [Abstract]
Disaggregation of Revenue	The following table summarizes total revenues as presented in the Unaudited Consolidated Statements of Income and the related amounts which are from contracts with customers within the scope of Topic 606. As shown below, a substantial portion of our revenues are specifically excluded from the scope of Topic 606. For the three month ended September 30, 2018 2017 (Dollars in thousands) As reported in Consolidated Statements of Income Revenue from contracts in scope of Topic 606 As reported in Consolidated Statements of Income Revenue from contracts in scope of Topic 606 Net interest income $33,449 $— $30,059 $— Noninterest income: Asset-based wealth management revenues 9,322 9,322 9,791 9,791 Transaction-based wealth management revenues 132 132 222 222 Total wealth management revenues 9,454 9,454 10,013 10,013 Mortgage banking revenues 2,624 — 3,036 — Service charges on deposit accounts 885 885 942 942 Card interchange fees 983 983 894 894 Income from bank-owned life insurance 572 — 546 — Loan related derivative income 278 — 1,452 — Other income 419 419 400 400 Total noninterest income 15,215 11,741 17,283 12,249 Total revenues $48,664 $11,741 $47,342 $12,249 For the nine months ended September 30, 2018 2017 (Dollars in thousands) As reported in Consolidated Statements of Income Revenue from contracts in scope of Topic 606 As reported in Consolidated Statements of Income Revenue from contracts in scope of Topic 606 Net interest income $98,412 $— $88,642 $— Noninterest income: Asset-based wealth management revenues 28,413 28,413 28,439 28,439 Transaction-based wealth management revenues 916 916 993 993 Total wealth management revenues 29,329 29,329 29,432 29,432 Mortgage banking revenues 8,403 — 8,295 — Service charges on deposit accounts 2,651 2,651 2,726 2,726 Card interchange fees 2,791 2,791 2,598 2,598 Income from bank-owned life insurance 1,624 — 1,624 — Loan related derivative income 1,087 — 2,744 — Other income 1,066 1,051 1,180 1,139 Total noninterest income 46,951 35,822 48,599 35,895 Total revenues $145,363 $35,822 $137,241 $35,895 The following table presents revenue from contracts with customers based on the timing of revenue recognition: (Dollars in thousands) Three Months Nine Months Periods ended September 30, 2018 2017 2018 2017 Revenue recognized at a point in time: Card interchange fees $983 $894 $2,791 $2,598 Service charges on deposit accounts 670 741 2,045 2,140 Other income 258 283 732 872 Revenue recognized over time: Wealth management revenues 9,454 10,013 29,329 29,432 Service charges on deposit accounts 215 201 606 586 Other income 161 117 319 267 Total revenues from contracts in scope of Topic 606 $11,741 $12,249 $35,822 $35,895

Defined Benefit Pension Plans (

Defined Benefit Pension Plans (Tables)	9 Months Ended
	Sep. 30, 2018
Defined Benefit Plan [Abstract]
Components of Net Periodic Benefit Cost	The composition of net periodic benefit cost was as follows: (Dollars in thousands) Qualified Pension Plan Non-Qualified Retirement Plans Three Months Nine Months Three Months Nine Months Periods ended September 30, 2018 2017 2018 2017 2018 2017 2018 2017 Net Periodic Benefit Cost: Service cost (1) $561 $537 $1,683 $1,611 $27 $32 $81 $97 Interest cost (2) 679 669 2,036 2,005 119 107 356 321 Expected return on plan assets (2) (1,318 ) (1,236 ) (3,954 ) (3,707 ) — — — — Amortization of prior service (credit) cost (2) (6 ) (6 ) (17 ) (17 ) — — — — Recognized net actuarial loss (2) 374 279 1,122 836 103 76 308 269 Net periodic benefit cost $290 $243 $870 $728 $249 $215 $745 $687 (1) Included in salaries and employee benefits expense in the Unaudited Consolidated Statements of Income. (2) Included in other expenses in the Unaudited Consolidated Statements of Income.
Schedule of Assumptions Used for Net Periodic Benefit Cost	The following table presents the measurement date and weighted-average assumptions used to determine net periodic benefit cost: Qualified Pension Plan Non-Qualified Retirement Plans For the nine months ended September 30, 2018 2017 2018 2017 Measurement date Dec 31, 2017 Dec 31, 2016 Dec 31, 2017 Dec 31, 2016 Equivalent single discount rate for benefit obligations 3.69% 4.18% 3.58% 3.96% Equivalent single discount rate for service cost 3.76 4.29 3.79 4.25 Equivalent single discount rate for interest cost 3.42 3.73 3.22 3.36 Expected long-term return on plan assets 6.75 6.75 N/A N/A Rate of compensation increase 3.75 3.75 3.75 3.75

Business Segments (Tables)

Business Segments (Tables)	9 Months Ended
	Sep. 30, 2018
Segment Reporting [Abstract]
Statement of Operations and Total Assets by Reportable Segment	The following table presents the statement of operations and total assets for Washington Trust’s reportable segments: (Dollars in thousands) Commercial Banking Wealth Management Services Corporate Consolidated Total Three months ended September 30, 2018 2017 2018 2017 2018 2017 2018 2017 Net interest income (expense) $27,036 $24,795 ($90 ) ($48 ) $6,503 $5,312 $33,449 $30,059 Provision for loan losses 350 1,300 — — — — 350 1,300 Net interest income (expense) after provision for loan losses 26,686 23,495 (90 ) (48 ) 6,503 5,312 33,099 28,759 Noninterest income 5,174 6,711 9,454 10,013 587 559 15,215 17,283 Noninterest expenses: Depreciation and amortization expense 654 646 371 411 44 50 1,069 1,107 Other noninterest expenses 15,599 15,834 6,194 6,810 3,200 3,003 24,993 25,647 Total noninterest expenses 16,253 16,480 6,565 7,221 3,244 3,053 26,062 26,754 Income before income taxes 15,607 13,726 2,799 2,744 3,846 2,818 22,252 19,288 Income tax expense 3,344 4,463 710 1,092 687 771 4,741 6,326 Net income $12,263 $9,263 $2,089 $1,652 $3,159 $2,047 $17,511 $12,962 Total assets at period end $3,694,991 $3,486,783 $69,494 $63,600 $1,006,187 $918,847 $4,770,672 $4,469,230 Expenditures for long-lived assets 612 890 14 25 19 22 645 937 (Dollars in thousands) Commercial Banking Wealth Management Services Corporate Consolidated Total Nine months ended September 30, 2018 2017 2018 2017 2018 2017 2018 2017 Net interest income (expense) $79,656 $72,985 ($225 ) ($120 ) $18,981 $15,777 $98,412 $88,642 Provision for loan losses 750 2,400 — — — — 750 2,400 Net interest income (expense) after provision for loan losses 78,906 70,585 (225 ) (120 ) 18,981 15,777 97,662 86,242 Noninterest income 15,947 17,500 29,329 29,432 1,675 1,667 46,951 48,599 Noninterest expenses: Depreciation and amortization expense 1,928 1,960 1,137 1,288 129 152 3,194 3,400 Other noninterest expenses 46,574 45,764 19,986 20,106 9,726 9,076 76,286 74,946 Total noninterest expenses 48,502 47,724 21,123 21,394 9,855 9,228 79,480 78,346 Income before income taxes 46,351 40,361 7,981 7,918 10,801 8,216 65,133 56,495 Income tax expense 9,834 13,142 2,008 3,172 1,895 2,238 13,737 18,552 Net income $36,517 $27,219 $5,973 $4,746 $8,906 $5,978 $51,396 $37,943 Total assets at period end $3,694,991 $3,486,783 $69,494 $63,600 $1,006,187 $918,847 $4,770,672 $4,469,230 Expenditures for long-lived assets 1,864 1,640 327 368 129 176 2,320 2,184

Other Comprehensive Income (L_2

Other Comprehensive Income (Loss) (Tables)	9 Months Ended
	Sep. 30, 2018
Equity [Abstract]
Activity in Other Comprehensive Income (Loss)	The following tables present the activity in other comprehensive income (loss): Three months ended September 30, 2018 2017 (Dollars in thousands) Pre-tax Amounts Income Taxes Net of Tax Pre-tax Amounts Income Taxes Net of Tax Securities available for sale: Changes in fair value of securities available for sale ($5,924 ) ($1,393 ) ($4,531 ) $1,736 $642 $1,094 Net gains on securities reclassified into earnings — — — — — — Net change in fair value of securities available for sale (5,924 ) (1,393 ) (4,531 ) 1,736 642 1,094 Cash flow hedges: Change in fair value of cash flow hedges (626 ) (148 ) (478 ) (237 ) (83 ) (154 ) Net cash flow hedge losses reclassified into earnings (1) 830 197 633 224 83 141 Net change in fair value of cash flow hedges 204 49 155 (13 ) — (13 ) Defined benefit plan obligations: Defined benefit plan obligation adjustment — — — — — — Amortization of net actuarial losses (2) 477 112 365 355 134 221 Amortization of net prior service credits (2) (6 ) (2 ) (4 ) (6 ) (2 ) (4 ) Net change in defined benefit plan obligations 471 110 361 349 132 217 Total other comprehensive (loss) income ($5,249 ) ($1,234 ) ($4,015 ) $2,072 $774 $1,298 (1) The pre-tax amounts are included in interest expense on FHLB advances, interest expense on junior subordinated debentures and interest and fees on loans in the Unaudited Consolidated Statements of Income. (2) The pre-tax amounts are included in other expenses in the Unaudited Consolidated Statements of Income. Nine months ended September 30, 2018 2017 (Dollars in thousands) Pre-tax Amounts Income Taxes Net of Tax Pre-tax Amounts Income Taxes Net of Tax Securities available for sale: Changes in fair value of securities available for sale ($23,605 ) ($5,548 ) ($18,057 ) $5,274 $1,951 $3,323 Net gains on securities reclassified into earnings — — — — — — Net change in fair value of securities available for sale (23,605 ) (5,548 ) (18,057 ) 5,274 1,951 3,323 Cash flow hedges: Change in fair value of cash flow hedges 632 50 582 (1,064 ) (361 ) (703 ) Net cash flow hedge losses reclassified into earnings (1) 1,082 255 827 539 200 339 Net change in fair value of cash flow hedges 1,714 305 1,409 (525 ) (161 ) (364 ) Defined benefit plan obligations: Defined benefit plan obligation adjustment — — — (407 ) (150 ) (257 ) Amortization of net actuarial losses (2) 1,430 337 1,093 1,105 411 694 Amortization of net prior service credits (2) (17 ) (5 ) (12 ) (17 ) (7 ) (10 ) Net change in defined benefit plan obligations 1,413 332 1,081 681 254 427 Total other comprehensive (loss) income ($20,478 ) ($4,911 ) ($15,567 ) $5,430 $2,044 $3,386 (1) The pre-tax amounts are included in interest expense on FHLB advances, interest expense on junior subordinated debentures and interest and fees on loans in the Unaudited Consolidated Statements of Income. (2) The pre-tax amounts are included in other expenses in the Unaudited Consolidated Statements of Income.
Components of Accumulated Other Comprehensive Income (Loss)	The following tables present the changes in accumulated other comprehensive income (loss) by component, net of tax: (Dollars in thousands) Net Unrealized Losses on Available For Sale Securities Net Unrealized (Losses) Gains on Cash Flow Hedges Pension Benefit Adjustment Total Balance at December 31, 2017 ($7,534 ) ($428 ) ($15,548 ) ($23,510 ) Other comprehensive (loss) income before reclassifications (18,057 ) 582 — (17,475 ) Amounts reclassified from accumulated other comprehensive income — 827 1,081 1,908 Net other comprehensive (loss) income (18,057 ) 1,409 1,081 (15,567 ) Balance at September 30, 2018 ($25,591 ) $981 ($14,467 ) ($39,077 ) (Dollars in thousands) Net Unrealized (Losses) Gains on Available For Sale Securities Net Unrealized Losses on Cash Flow Hedges Pension Benefit Adjustment Total Balance at December 31, 2016 ($6,825 ) ($300 ) ($12,632 ) ($19,757 ) Other comprehensive income (loss) before reclassifications 3,323 (703 ) — 2,620 Amounts reclassified from accumulated other comprehensive income — 339 427 766 Net other comprehensive income (loss) 3,323 (364 ) 427 3,386 Balance at September 30, 2017 ($3,502 ) ($664 ) ($12,205 ) ($16,371 )

Earnings Per Common Share (Tabl

Earnings Per Common Share (Tables)	9 Months Ended
	Sep. 30, 2018
Earnings Per Share [Abstract]
Calculation of Earnings Per Share	The following table presents the calculation of earnings per common share: (Dollars and shares in thousands, except per share amounts) Three Months Nine Months Periods ended September 30, 2018 2017 2018 2017 Earnings per common share - basic: Net income $17,511 $12,962 $51,396 $37,943 Less dividends and undistributed earnings allocated to participating securities (36 ) (28 ) (112 ) (84 ) Net income applicable to common shareholders $17,475 $12,934 $51,284 $37,859 Weighted average common shares 17,283 17,212 17,263 17,201 Earnings per common share - basic $1.01 $0.75 $2.97 $2.20 Earnings per common share - diluted: Net income $17,511 $12,962 $51,396 $37,943 Less dividends and undistributed earnings allocated to participating securities (36 ) (28 ) (112 ) (84 ) Net income applicable to common shareholders $17,475 $12,934 $51,284 $37,859 Weighted average common shares 17,283 17,212 17,263 17,201 Dilutive effect of common stock equivalents 99 106 129 119 Weighted average diluted common shares 17,382 17,318 17,392 17,320 Earnings per common share - diluted $1.01 $0.75 $2.95 $2.19

Commitments and Contingencies (

Commitments and Contingencies (Tables)	9 Months Ended
	Sep. 30, 2018
Commitments and Contingencies Disclosure [Abstract]
Financial Instruments with Off Balance Sheet Risk	The following table presents the contractual and notional amounts of financial instruments with off-balance sheet risk: (Dollars in thousands) Sep 30, Dec 31, Financial instruments whose contract amounts represent credit risk: Commitments to extend credit: Commercial loans $519,887 $537,310 Home equity lines 266,886 254,855 Other loans 44,665 48,819 Standby letters of credit 7,993 6,666 Financial instruments whose notional amounts exceed the amount of credit risk: Forward loan commitments: Interest rate lock commitments 38,612 45,139 Forward sale commitments 65,686 71,539 Loan related derivative contracts: Interest rate swaps with customers 574,364 545,049 Mirror swaps with counterparties 574,364 545,049 Risk participation-in agreements 36,610 34,052 Foreign exchange contracts 2,907 3,005 Interest rate risk management contracts: Interest rate swaps 60,000 60,000
Schedule of Future Minimum Annual Lease Payments	The following table presents the minimum annual lease payments under the terms of these leases, exclusive of renewal provisions: (Dollars in thousands) October 1, 2018 to December 31, 2018 $933 2019 3,579 2020 2,860 2021 2,526 2022 2,133 2023 and thereafter 24,595 Total minimum lease payments $36,626

Recently Issued Accounting Pr_2

Recently Issued Accounting Pronouncements (Details) $ in Thousands	Sep. 30, 2018USD ($)
New Accounting Pronouncements and Changes in Accounting Principles [Abstract]
Operating Leases, Future Minimum Payments Due	$ 36,626

Cash and Due from Banks (Narrat

Cash and Due from Banks (Narrative) (Details) - USD ($) $ in Millions	Sep. 30, 2018	Dec. 31, 2017
Cash and Cash Equivalents [Abstract]
Average reserve deposited with the Board of Governors of the Federal Reserve Bank	$ 20.7	$ 14.1
Interest-bearing deposits in other banks	$ 20.8	$ 31.9

Securities (Narrative) (Details

Securities (Narrative) (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2018USD ($)security	Dec. 31, 2017USD ($)security
Schedule of Available for Sale and Held to Maturty Securities [Line Items]
Fair value of available for sale and held to maturity securities pledged as collateral	$ 356,500	$ 357,800
Amortized cost of callable debt securities	228,600
Fair value of callable debt securities	$ 218,900
Number of securities in a continuous unrealized loss position total | security	104	71
Available for Sale Securities, Continuous Unrealized Loss Position, Aggregate Losses, Accumulated Investments	$ 34,812	$ 13,535
Individual name issuer trust preferred debt securities
Schedule of Available for Sale and Held to Maturty Securities [Line Items]
Number of securities in a continuous unrealized loss position total | security	5	7
Securities in unrealized loss position, number of companies issuing securities | security	4
Amortized cost of trust preferred securities of individual name issuers that are below investment grade	$ 6,100
Unrealized losses of trust preferred securities of individual name issuers that are below investment grade	(411)
Available for Sale Securities, Continuous Unrealized Loss Position, Aggregate Losses, Accumulated Investments	$ 839	$ 1,122
Corporate bonds [Member]
Schedule of Available for Sale and Held to Maturty Securities [Line Items]
Number of securities in a continuous unrealized loss position total | security	9	6
Available for Sale Securities, Continuous Unrealized Loss Position, Aggregate Losses, Accumulated Investments	$ 1,000	$ 805
Minimum [Member]
Schedule of Available for Sale and Held to Maturty Securities [Line Items]
Maturity period of callable debt securities	8 months
Call features of callable debt securities	1 month
Maximum [Member]
Schedule of Available for Sale and Held to Maturty Securities [Line Items]
Maturity period of callable debt securities	18 years
Call features of callable debt securities	3 years

Securities (Summary of Investme

Securities (Summary of Investments) (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Schedule of Available for Sale and Held to Maturty Securities [Line Items]
Available for sale securities amortized cost basis	$ 846,099	$ 790,801
Available for sale securities unrealized gains	1,154	3,688
Available for sale securities unrealized losses	(34,606)	(13,535)
Available for sale, at fair value	812,647	780,954
Held to maturity securities	10,863	12,541
Held to maturity securities unrealized gains	0	180
Held to maturity securities unrealized losses	(206)	0
Held to maturity securities fair value	10,657	12,721
Total available for sale and held to maturity securities amortized cost	856,962	803,342
Total available for sale and held to maturity securities unrealized gains	1,154	3,868
Total available for sale and held to maturity securities unrealized losses	(34,812)	(13,535)
Total available for sale and held to maturity securities fair value	823,304	793,675
Obligations of U.S. government-sponsored enterprises [Member]
Schedule of Available for Sale and Held to Maturty Securities [Line Items]
Available for sale securities amortized cost basis	201,398	161,479
Available for sale securities unrealized gains	9	0
Available for sale securities unrealized losses	(7,934)	(3,875)
Available for sale, at fair value	193,473	157,604
Mortgage-backed securities issued by U.S. government-sponsored agencies and U.S. government-sponsored enterprises [Member]
Schedule of Available for Sale and Held to Maturty Securities [Line Items]
Available for sale securities amortized cost basis	616,552	594,944
Available for sale securities unrealized gains	1,143	3,671
Available for sale securities unrealized losses	(24,833)	(7,733)
Available for sale, at fair value	592,862	590,882
Held to maturity securities	10,863	12,541
Held to maturity securities unrealized gains	0	180
Held to maturity securities unrealized losses	(206)	0
Held to maturity securities fair value	10,657	12,721
Obligations of states and political subdivisions [Member]
Schedule of Available for Sale and Held to Maturty Securities [Line Items]
Available for sale securities amortized cost basis	935	2,355
Available for sale securities unrealized gains	2	4
Available for sale securities unrealized losses	0	0
Available for sale, at fair value	937	2,359
Individual name issuer trust preferred debt securities
Schedule of Available for Sale and Held to Maturty Securities [Line Items]
Available for sale securities amortized cost basis	13,303	18,106
Available for sale securities unrealized gains	0	0
Available for sale securities unrealized losses	(839)	(1,122)
Available for sale, at fair value	12,464	16,984
Corporate bonds [Member]
Schedule of Available for Sale and Held to Maturty Securities [Line Items]
Available for sale securities amortized cost basis	13,911	13,917
Available for sale securities unrealized gains	0	13
Available for sale securities unrealized losses	(1,000)	(805)
Available for sale, at fair value	$ 12,911	$ 13,125

Securities (Securities by Contr

Securities (Securities by Contractual Maturity) (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Schedule of Available for Sale and Held to Maturty Securities [Line Items]
Available for sale debt securities maturities within 1 year amortized cost	$ 64,023
Available for sale debt securities maturities 1-5 years amortized cost	314,353
Available for sale debt securities maturities 5-10 years amortized cost	278,106
Available for sale debt securities maturities after 10 years amortized cost	189,617
Available for sale debt securities maturities total amortized cost	846,099
Available for sale debt securities maturities within 1 year fair value	61,577
Available for sale debt securities maturities 1-5 years fair value	302,124
Available for sale debt securities maturities 5-10 years fair value	266,878
Available for sale debt securities maturities after 10 years fair value	182,068
Available for sale debt securities fair value	812,647
Held to maturity debt securities maturities within 1 year amortized cost	1,370
Held to maturity debt securities maturities 1-5 years amortized cost	4,529
Held to maturity debt securities maturities 5-10 years amortized cost	3,709
Held to maturity debt securities maturities after 10 years amortized cost	1,255
Held to maturity securities	10,863	$ 12,541
Held to maturity debt securities maturities within 1 year fair value	1,344
Held to maturity debt securities maturities 1-5 years fair value	4,443
Held to maturity debt securities maturities 5-10 years fair value	3,639
Held to maturity debt securities maturities after 10 years fair value	1,231
Held to maturity securities fair value	$ 10,657	$ 12,721

Securities (Securities in a Con

Securities (Securities in a Continuous Unrealized Loss Position) (Details) $ in Thousands	Sep. 30, 2018USD ($)security	Dec. 31, 2017USD ($)security
Schedule of Available-for-sale Securities [Line Items]
Number of securities in a continuous unrealized loss position for less than 12 months | security	49	31
Fair value of securities in a continuous unrealized loss position for less than 12 months	$ 315,564	$ 199,567
Unrealized losses of securities in a continuous unrealized loss position for less than 12 months	$ (8,620)	$ (1,416)
Number of securities in a continuous unrealized loss position for 12 months or longer | security	55	40
Fair value of securities in a continuous unrealized loss position for 12 months or longer	$ 434,212	$ 395,580
Unrealized losses of securities in a continuous unrealized loss position for 12 months or longer	$ (26,192)	$ (12,119)
Number of securities in a continuous unrealized loss position total | security	104	71
Fair value of securities in a continuous unrealized loss position total	$ 749,776	$ 595,147
Unrealized losses of securities in a continuous unrealized loss position total	$ (34,812)	$ (13,535)
Obligations of U.S. government-sponsored enterprises [Member]
Schedule of Available-for-sale Securities [Line Items]
Number of securities in a continuous unrealized loss position for less than 12 months | security	8	8
Fair value of securities in a continuous unrealized loss position for less than 12 months	$ 77,958	$ 69,681
Unrealized losses of securities in a continuous unrealized loss position for less than 12 months	$ (2,040)	$ (798)
Number of securities in a continuous unrealized loss position for 12 months or longer | security	11	8
Fair value of securities in a continuous unrealized loss position for 12 months or longer	$ 105,606	$ 87,923
Unrealized losses of securities in a continuous unrealized loss position for 12 months or longer	$ (5,894)	$ (3,077)
Number of securities in a continuous unrealized loss position total | security	19	16
Fair value of securities in a continuous unrealized loss position total	$ 183,564	$ 157,604
Unrealized losses of securities in a continuous unrealized loss position total	$ (7,934)	$ (3,875)
Mortgage-backed securities issued by U.S. government-sponsored agencies and U.S. government-sponsored enterprises [Member]
Schedule of Available-for-sale Securities [Line Items]
Number of securities in a continuous unrealized loss position for less than 12 months | security	37	20
Fair value of securities in a continuous unrealized loss position for less than 12 months	$ 235,900	$ 128,965
Unrealized losses of securities in a continuous unrealized loss position for less than 12 months	$ (6,567)	$ (613)
Number of securities in a continuous unrealized loss position for 12 months or longer | security	34	22
Fair value of securities in a continuous unrealized loss position for 12 months or longer	$ 304,937	$ 279,693
Unrealized losses of securities in a continuous unrealized loss position for 12 months or longer	$ (18,472)	$ (7,120)
Number of securities in a continuous unrealized loss position total | security	71	42
Fair value of securities in a continuous unrealized loss position total	$ 540,837	$ 408,658
Unrealized losses of securities in a continuous unrealized loss position total	$ (25,039)	$ (7,733)
Individual name issuer trust preferred debt securities
Schedule of Available-for-sale Securities [Line Items]
Number of securities in a continuous unrealized loss position for less than 12 months | security	0	0
Fair value of securities in a continuous unrealized loss position for less than 12 months	$ 0	$ 0
Unrealized losses of securities in a continuous unrealized loss position for less than 12 months	$ 0	$ 0
Number of securities in a continuous unrealized loss position for 12 months or longer | security	5	7
Fair value of securities in a continuous unrealized loss position for 12 months or longer	$ 12,464	$ 16,984
Unrealized losses of securities in a continuous unrealized loss position for 12 months or longer	$ (839)	$ (1,122)
Number of securities in a continuous unrealized loss position total | security	5	7
Fair value of securities in a continuous unrealized loss position total	$ 12,464	$ 16,984
Unrealized losses of securities in a continuous unrealized loss position total	$ (839)	$ (1,122)
Corporate bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Number of securities in a continuous unrealized loss position for less than 12 months | security	4	3
Fair value of securities in a continuous unrealized loss position for less than 12 months	$ 1,706	$ 921
Unrealized losses of securities in a continuous unrealized loss position for less than 12 months	$ (13)	$ (5)
Number of securities in a continuous unrealized loss position for 12 months or longer | security	5	3
Fair value of securities in a continuous unrealized loss position for 12 months or longer	$ 11,205	$ 10,980
Unrealized losses of securities in a continuous unrealized loss position for 12 months or longer	$ (987)	$ (800)
Number of securities in a continuous unrealized loss position total | security	9	6
Fair value of securities in a continuous unrealized loss position total	$ 12,911	$ 11,901
Unrealized losses of securities in a continuous unrealized loss position total	$ (1,000)	$ (805)

Loans (Narrative) (Details)

Loans (Narrative) (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Receivables [Abstract]
Loans Receivable Net Deferred Cost Originated	$ 4,800	$ 3,800
Loans Receivable Net Deferred Premium on Purchased Loans	746	878
Loans Pledged as Collateral	1,900,000	1,600,000
Past due loans included in nonaccrual loans	6,400	11,800
Mortgage Loans in Process of Foreclosure	$ 800	$ 4,400

Loans (Summary of Loans) (Detai

Loans (Summary of Loans) (Details) - USD ($) $ in Thousands		Sep. 30, 2018	Dec. 31, 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	[1]	$ 3,556,203	$ 3,374,071
Percent of Total Loans	[1]	100.00%	100.00%
Commercial Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	[2]	$ 1,240,350	$ 1,210,495
Percent of Total Loans	[2]	35.00%	36.00%
Commercial & Industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	[3]	$ 656,882	$ 612,334
Percent of Total Loans	[3]	18.00%	18.00%
Total Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans		$ 1,897,232	$ 1,822,829
Percent of Total Loans		53.00%	54.00%
Residential Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	[4]	$ 1,349,340	$ 1,227,248
Percent of Total Loans	[4]	38.00%	36.00%
Home Equity
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans		$ 282,331	$ 292,467
Percent of Total Loans		8.00%	9.00%
Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	[5]	$ 27,300	$ 31,527
Percent of Total Loans	[5]	1.00%	1.00%
Total Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans		$ 309,631	$ 323,994
Percent of Total Loans		9.00%	10.00%
[1]	Includes net unamortized loan origination costs of $4.8 million and $3.8 million, respectively, at September 30, 2018 and December 31, 2017 and net unamortized premiums on purchased loans of $746 thousand and $878 thousand, respectively, at September 30, 2018 and December 31, 2017.
[2]	Commercial real estate loans consist of commercial mortgages primarily secured by income producing property, as well as construction and development loans. Construction and development loans are made to businesses for land development or the on-site construction of industrial, commercial, or residential buildings.
[3]	Commercial & industrial consist of loans to businesses and individuals, a substantial portion of which are fully or partially collateralized by real estate.
[4]	Residential real estate loans consist of mortgage and homeowner construction loans secured by one- to four- family residential properties.
[5]	Other consumer loans consists of loans to individuals secured by general aviation aircraft and other personal installment loans.

Loans (Past Due Loans) (Details

Loans (Past Due Loans) (Details) - USD ($) $ in Thousands		Sep. 30, 2018	Dec. 31, 2017
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due		$ 13,519	$ 20,075
Current		3,542,684	3,353,996
Total loans	[1]	3,556,203	3,374,071
30-59
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due		7,285	8,304
60-89
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due		4,421	2,351
Over 90
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due		1,813	9,420
Commercial Real Estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due		931	4,960
Current		1,239,419	1,205,535
Total loans	[2]	1,240,350	1,210,495
Commercial Real Estate | 30-59
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due		0	6
Commercial Real Estate | 60-89
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due		931	0
Commercial Real Estate | Over 90
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due		0	4,954
Commercial & Industrial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due		142	4,076
Current		656,740	608,258
Total loans	[3]	656,882	612,334
Commercial & Industrial | 30-59
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due		0	3,793
Commercial & Industrial | 60-89
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due		20	2
Commercial & Industrial | Over 90
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due		122	281
Total Commercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due		1,073	9,036
Current		1,896,159	1,813,793
Total loans		1,897,232	1,822,829
Total Commercial | 30-59
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due		0	3,799
Total Commercial | 60-89
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due		951	2
Total Commercial | Over 90
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due		122	5,235
Residential Real Estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due		9,398	7,855
Current		1,339,942	1,219,393
Total loans	[4]	1,349,340	1,227,248
Residential Real Estate | 30-59
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due		5,322	1,678
Residential Real Estate | 60-89
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due		2,936	2,274
Residential Real Estate | Over 90
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due		1,140	3,903
Home Equity
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due		2,939	3,141
Current		279,392	289,326
Total loans		282,331	292,467
Home Equity | 30-59
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due		1,854	2,798
Home Equity | 60-89
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due		534	75
Home Equity | Over 90
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due		551	268
Other
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due		109	43
Current		27,191	31,484
Total loans	[5]	27,300	31,527
Other | 30-59
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due		109	29
Other | 60-89
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due		0	0
Other | Over 90
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due		0	14
Total Consumer
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due		3,048	3,184
Current		306,583	320,810
Total loans		309,631	323,994
Total Consumer | 30-59
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due		1,963	2,827
Total Consumer | 60-89
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due		534	75
Total Consumer | Over 90
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due		$ 551	$ 282
[1]	Includes net unamortized loan origination costs of $4.8 million and $3.8 million, respectively, at September 30, 2018 and December 31, 2017 and net unamortized premiums on purchased loans of $746 thousand and $878 thousand, respectively, at September 30, 2018 and December 31, 2017.
[2]	Commercial real estate loans consist of commercial mortgages primarily secured by income producing property, as well as construction and development loans. Construction and development loans are made to businesses for land development or the on-site construction of industrial, commercial, or residential buildings.
[3]	Commercial & industrial consist of loans to businesses and individuals, a substantial portion of which are fully or partially collateralized by real estate.
[4]	Residential real estate loans consist of mortgage and homeowner construction loans secured by one- to four- family residential properties.
[5]	Other consumer loans consists of loans to individuals secured by general aviation aircraft and other personal installment loans.

Loans (Impaired Loans) (Details

Loans (Impaired Loans) (Details) - USD ($) $ in Thousands		Sep. 30, 2018	Dec. 31, 2017
Financing Receivable, Impaired [Line Items]
Recorded Investment of Impaired Loans with No Related Allowance	[1]	$ 15,144	$ 14,626
Recorded Investment of Impaired Loans with Related Allowance	[1]	821	5,993
Total Recorded Investment of Impaired Loans	[1]	15,965	20,619
Unpaid Principal of Impaired Loans with No Related Allowance		15,356	14,908
Unpaid Principal of Impaired Loans with Related Allowance		871	10,995
Total Unpaid Principal of Impaired Loans		16,227	25,903
No Related Allowance on Impaired Loans		0	0
Related Allowance on Impaired Loans		112	1,129
Commercial Real Estate
Financing Receivable, Impaired [Line Items]
Recorded Investment of Impaired Loans with No Related Allowance	[1]	0	0
Recorded Investment of Impaired Loans with Related Allowance	[1]	0	4,954
Unpaid Principal of Impaired Loans with No Related Allowance		0	0
Unpaid Principal of Impaired Loans with Related Allowance		0	9,910
No Related Allowance on Impaired Loans		0	0
Related Allowance on Impaired Loans		0	1,018
Commercial & Industrial
Financing Receivable, Impaired [Line Items]
Recorded Investment of Impaired Loans with No Related Allowance	[1]	4,825	4,986
Recorded Investment of Impaired Loans with Related Allowance	[1]	54	191
Unpaid Principal of Impaired Loans with No Related Allowance		4,877	5,081
Unpaid Principal of Impaired Loans with Related Allowance		75	212
No Related Allowance on Impaired Loans		0	0
Related Allowance on Impaired Loans		0	1
Total Commercial
Financing Receivable, Impaired [Line Items]
Recorded Investment of Impaired Loans with No Related Allowance	[1]	4,825	4,986
Recorded Investment of Impaired Loans with Related Allowance	[1]	54	5,145
Total Recorded Investment of Impaired Loans	[1]	4,879	10,131
Unpaid Principal of Impaired Loans with No Related Allowance		4,877	5,081
Unpaid Principal of Impaired Loans with Related Allowance		75	10,122
Total Unpaid Principal of Impaired Loans		4,952	15,203
No Related Allowance on Impaired Loans		0	0
Related Allowance on Impaired Loans		0	1,019
Residential Real Estate
Financing Receivable, Impaired [Line Items]
Recorded Investment of Impaired Loans with No Related Allowance	[1]	8,737	9,069
Recorded Investment of Impaired Loans with Related Allowance	[1]	692	715
Total Recorded Investment of Impaired Loans	[1]	9,429	9,784
Unpaid Principal of Impaired Loans with No Related Allowance		8,896	9,256
Unpaid Principal of Impaired Loans with Related Allowance		722	741
Total Unpaid Principal of Impaired Loans		9,618	9,997
No Related Allowance on Impaired Loans		0	0
Related Allowance on Impaired Loans		101	104
Home Equity
Financing Receivable, Impaired [Line Items]
Recorded Investment of Impaired Loans with No Related Allowance	[1]	1,582	557
Recorded Investment of Impaired Loans with Related Allowance	[1]	52	0
Unpaid Principal of Impaired Loans with No Related Allowance		1,583	557
Unpaid Principal of Impaired Loans with Related Allowance		51	0
No Related Allowance on Impaired Loans		0	0
Related Allowance on Impaired Loans		8	0
Other
Financing Receivable, Impaired [Line Items]
Recorded Investment of Impaired Loans with No Related Allowance	[1]	0	14
Recorded Investment of Impaired Loans with Related Allowance	[1]	23	133
Unpaid Principal of Impaired Loans with No Related Allowance		0	14
Unpaid Principal of Impaired Loans with Related Allowance		23	132
No Related Allowance on Impaired Loans		0	0
Related Allowance on Impaired Loans		3	6
Total Consumer
Financing Receivable, Impaired [Line Items]
Recorded Investment of Impaired Loans with No Related Allowance	[1]	1,582	571
Recorded Investment of Impaired Loans with Related Allowance	[1]	75	133
Total Recorded Investment of Impaired Loans	[1]	1,657	704
Unpaid Principal of Impaired Loans with No Related Allowance		1,583	571
Unpaid Principal of Impaired Loans with Related Allowance		74	132
Total Unpaid Principal of Impaired Loans		1,657	703
No Related Allowance on Impaired Loans		0	0
Related Allowance on Impaired Loans		$ 11	$ 6
[1]	The recorded investment in impaired loans consists of unpaid principal balance, net of charge-offs, interest payments received applied to principal and unamortized deferred loan origination fees and costs. For accruing impaired loans (troubled debt restructurings for which management has concluded that the collectibility of the loan is not in doubt), the recorded investment also includes accrued interest.

Loans (Impaired Loans Interest

Loans (Impaired Loans Interest Income Recognized) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Financing Receivable, Impaired [Line Items]
Average Recorded Investment of Impaired Loans	$ 16,038	$ 30,260	$ 17,790	$ 32,493
Interest Income Recognized on Impaired Loans	180	197	540	699
Commercial Real Estate
Financing Receivable, Impaired [Line Items]
Average Recorded Investment of Impaired Loans	0	8,041	1,352	9,117
Interest Income Recognized on Impaired Loans	0	21	0	73
Commercial & Industrial
Financing Receivable, Impaired [Line Items]
Average Recorded Investment of Impaired Loans	5,324	6,427	5,599	6,750
Interest Income Recognized on Impaired Loans	62	67	201	219
Total Commercial
Financing Receivable, Impaired [Line Items]
Average Recorded Investment of Impaired Loans	5,324	14,468	6,951	15,867
Interest Income Recognized on Impaired Loans	62	88	201	292
Residential Real Estate
Financing Receivable, Impaired [Line Items]
Average Recorded Investment of Impaired Loans	9,265	15,107	9,709	15,750
Interest Income Recognized on Impaired Loans	96	102	293	374
Home Equity
Financing Receivable, Impaired [Line Items]
Average Recorded Investment of Impaired Loans	1,424	543	1,045	734
Interest Income Recognized on Impaired Loans	22	5	41	25
Other
Financing Receivable, Impaired [Line Items]
Average Recorded Investment of Impaired Loans	25	142	85	142
Interest Income Recognized on Impaired Loans	0	2	5	8
Total Consumer
Financing Receivable, Impaired [Line Items]
Average Recorded Investment of Impaired Loans	1,449	685	1,130	876
Interest Income Recognized on Impaired Loans	$ 22	$ 7	$ 46	$ 33

Loans (Nonaccrual Loans) (Detai

Loans (Nonaccrual Loans) (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual loans	$ 10,809	$ 15,211
Accruing loans 90 days or more past due	0	0
Current Payment Status [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual loans current on payment	4,400	3,400
Commercial Real Estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual loans	0	4,954
Commercial & Industrial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual loans	122	283
Total Commercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual loans	122	5,237
Residential Real Estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual loans	9,063	9,414
Home Equity
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual loans	1,624	544
Other Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual loans	0	16
Total Consumer
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual loans	$ 1,624	$ 560

Loans (Narrative - Troubled Deb

Loans (Narrative - Troubled Debt Restructurings) (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Receivables [Abstract]
Recorded investment in Troubled Debt Restructuring, Recorded Investment	$ 5,700	$ 11,200
Specific Reserves on Troubled Debt Restructurings	$ 104	$ 1,100

Loans Loans (Troubled Debt Rest

Loans Loans (Troubled Debt Restructurings Type of Modification) (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018USD ($)loan	Sep. 30, 2017USD ($)loan	Sep. 30, 2018USD ($)loan	Sep. 30, 2017USD ($)loan
Financing Receivable, Modifications [Line Items]
Number of loans modified as a troubled debt restructuring | loan	0	0	1	0
Troubled debt restructuring, pre-modification recorded investment	$ 0	$ 0	$ 608	$ 0
Troubled debt restructuring, post-modification recorded investment	$ 0	$ 0	$ 608	$ 0

Loans Loans (Troubled Debt Re_2

Loans Loans (Troubled Debt Restructurings Subsequent Default) (Details) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018USD ($)loan	Sep. 30, 2017USD ($)loan	Sep. 30, 2018USD ($)loan	Sep. 30, 2017USD ($)loan
Financing Receivable, Modifications [Line Items]
Number of loans modified as a troubled debt restructuring	0	0	1	0
Payment Default [Member]
Financing Receivable, Modifications [Line Items]
Number of loans modified as a troubled debt restructuring	1	0	0	2
Recorded investment on TDR modifications with payment default | $	$ 0.6	$ 0	$ 0	$ 1.6

Loans (Narrative - Credit Quali

Loans (Narrative - Credit Quality Indicators) (Details) - rating	Sep. 30, 2018	Dec. 31, 2017
Receivables [Abstract]
Weighted Average Commercial Loan Portfolio Risk Rating	4.74	4.70

Loans (Credit Quality Indicator

Loans (Credit Quality Indicators - Commercial) (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Commercial Mortgages | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans Receivable
Commercial Mortgages | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans Receivable
Commercial Mortgages | Classified [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans Receivable
Commercial Construction & Development | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans Receivable
Commercial Construction & Development | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans Receivable
Commercial Construction & Development | Classified [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans Receivable
Commercial Real Estate | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans Receivable	1,235,579	1,205,381
Commercial Real Estate | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans Receivable	1,065	0
Commercial Real Estate | Classified [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans Receivable	3,706	5,114
Commercial & Industrial | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans Receivable	593,673	592,749
Commercial & Industrial | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans Receivable	55,012	9,804
Commercial & Industrial | Classified [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans Receivable	8,197	9,781
Total Commercial | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans Receivable	1,829,252	1,798,130
Total Commercial | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans Receivable	56,077	9,804
Total Commercial | Classified [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans Receivable	$ 11,903	$ 14,895

Loans (Credit Quality Indicat_2

Loans (Credit Quality Indicators - Residential, Consumer) (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Financing Receivable, Recorded Investment [Line Items]
Current	$ 3,542,684	$ 3,353,996
Total past due	13,519	20,075
Self-originated Mortgages
Financing Receivable, Recorded Investment [Line Items]
Current	1,224,575	1,091,291
Total past due	8,172	6,413
Purchased Mortgages
Financing Receivable, Recorded Investment [Line Items]
Current	115,367	128,102
Total past due	1,226	1,442
Residential Real Estate
Financing Receivable, Recorded Investment [Line Items]
Current	1,339,942	1,219,393
Total past due	9,398	7,855
Home Equity
Financing Receivable, Recorded Investment [Line Items]
Current	279,392	289,326
Total past due	2,939	3,141
Other
Financing Receivable, Recorded Investment [Line Items]
Current	27,191	31,484
Total past due	109	43
Total Consumer
Financing Receivable, Recorded Investment [Line Items]
Current	306,583	320,810
Total past due	$ 3,048	$ 3,184

Allowance for Loan Losses (All

Allowance for Loan Losses (Allowance for Loan Losses Rollforward Analysis) (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance, Beginning Balance		$ 26,174	$ 26,662	$ 26,488	$ 26,004
Charge-offs		(96)	(694)	(889)	(1,415)
Recoveries		81	40	160	319
Provision		350	1,300	750	2,400
Allowance, Ending Balance		26,509	27,308	26,509	27,308
Commercial Real Estate
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance, Beginning Balance	[1]	12,443	11,935	12,729	11,166
Charge-offs	[1]	0	(535)	(627)	(935)
Recoveries	[1]	0	0	25	82
Provision	[1]	1,052	1,387	1,368	2,474
Allowance, Ending Balance	[1]	13,495	12,787	13,495	12,787
Commercial & Industrial
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance, Beginning Balance	[2]	6,642	7,067	5,580	6,992
Charge-offs	[2]	(1)	(122)	(8)	(286)
Recoveries	[2]	71	8	104	162
Provision	[2]	535	(301)	1,571	(216)
Allowance, Ending Balance	[2]	7,247	6,652	7,247	6,652
Total Commercial
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance, Beginning Balance		19,085	19,002	18,309	18,158
Charge-offs		(1)	(657)	(635)	(1,221)
Recoveries		71	8	129	244
Provision		1,587	1,086	2,939	2,258
Allowance, Ending Balance		20,742	19,439	20,742	19,439
Residential Real Estate
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance, Beginning Balance		5,314	5,369	5,427	5,252
Charge-offs		(68)	0	(73)	(32)
Recoveries		0	1	0	29
Provision		(1,131)	70	(1,239)	191
Allowance, Ending Balance		4,115	5,440	4,115	5,440
Home Equity
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance, Beginning Balance		1,375	1,927	2,412	1,889
Charge-offs		0	(18)	(111)	(79)
Recoveries		2	25	12	31
Provision		12	(27)	(924)	66
Allowance, Ending Balance		1,389	1,907	1,389	1,907
Other
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance, Beginning Balance		400	364	340	705
Charge-offs		(27)	(19)	(70)	(83)
Recoveries		8	6	19	15
Provision		(118)	171	(26)	(115)
Allowance, Ending Balance		263	522	263	522
Total Consumer
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance, Beginning Balance		1,775	2,291	2,752	2,594
Charge-offs		(27)	(37)	(181)	(162)
Recoveries		10	31	31	46
Provision		(106)	144	(950)	(49)
Allowance, Ending Balance		$ 1,652	$ 2,429	$ 1,652	$ 2,429
[1]	Commercial real estate loans.
[2]	Commercial & industrial loans.

Allowance for Loan Losses (Allo

Allowance for Loan Losses (Allowance for Loan Losses by Segment & Impairment Methodology) (Details) - USD ($) $ in Thousands		Sep. 30, 2018	Dec. 31, 2017
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for impairment		$ 15,945	$ 20,598
Loans related allowance individually evaluated for impairment		112	1,129
Loans collectively evaluated for impairment		3,540,258	3,353,473
Loans related allowance collectively evaluated for impairment		26,397	25,359
Total loans	[1]	3,556,203	3,374,071
Allowance		26,509	26,488
Commercial Real Estate
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for impairment		0	4,954
Loans related allowance individually evaluated for impairment		0	1,018
Loans collectively evaluated for impairment		1,240,350	1,205,541
Loans related allowance collectively evaluated for impairment		13,495	11,711
Total loans	[2]	1,240,350	1,210,495
Commercial & Industrial
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for impairment		4,860	5,157
Loans related allowance individually evaluated for impairment		0	1
Loans collectively evaluated for impairment		652,022	607,177
Loans related allowance collectively evaluated for impairment		7,247	5,579
Total loans	[3]	656,882	612,334
Total Commercial
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for impairment		4,860	10,111
Loans related allowance individually evaluated for impairment		0	1,019
Loans collectively evaluated for impairment		1,892,372	1,812,718
Loans related allowance collectively evaluated for impairment		20,742	17,290
Total loans		1,897,232	1,822,829
Residential Real Estate
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for impairment		9,428	9,783
Loans related allowance individually evaluated for impairment		101	104
Loans collectively evaluated for impairment		1,339,912	1,217,465
Loans related allowance collectively evaluated for impairment		4,014	5,323
Total loans	[4]	1,349,340	1,227,248
Home Equity
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for impairment		1,635	557
Loans related allowance individually evaluated for impairment		9	0
Loans collectively evaluated for impairment		280,696	291,910
Loans related allowance collectively evaluated for impairment		1,380	2,412
Total loans		282,331	292,467
Other
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for impairment		22	147
Loans related allowance individually evaluated for impairment		2	6
Loans collectively evaluated for impairment		27,278	31,380
Loans related allowance collectively evaluated for impairment		261	334
Total loans	[5]	27,300	31,527
Total Consumer
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for impairment		1,657	704
Loans related allowance individually evaluated for impairment		11	6
Loans collectively evaluated for impairment		307,974	323,290
Loans related allowance collectively evaluated for impairment		1,641	2,746
Total loans		$ 309,631	$ 323,994
[1]	Includes net unamortized loan origination costs of $4.8 million and $3.8 million, respectively, at September 30, 2018 and December 31, 2017 and net unamortized premiums on purchased loans of $746 thousand and $878 thousand, respectively, at September 30, 2018 and December 31, 2017.
[2]	Commercial real estate loans consist of commercial mortgages primarily secured by income producing property, as well as construction and development loans. Construction and development loans are made to businesses for land development or the on-site construction of industrial, commercial, or residential buildings.
[3]	Commercial & industrial consist of loans to businesses and individuals, a substantial portion of which are fully or partially collateralized by real estate.
[4]	Residential real estate loans consist of mortgage and homeowner construction loans secured by one- to four- family residential properties.
[5]	Other consumer loans consists of loans to individuals secured by general aviation aircraft and other personal installment loans.

Borrowings (Narrative Federal H

Borrowings (Narrative Federal Home Loan Bank Advances) (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Federal Home Loan Bank, Advances, Branch of FHLBB Bank [Line Items]
Federal Home Loan Bank advances	$ 828,392	$ 791,356
Federal Home Loan Bank of Boston [Member]
Federal Home Loan Bank, Advances, Branch of FHLBB Bank [Line Items]
Federal Home Loan Bank advances	828,392	791,356
Unused line of credit with FHLBB	40,000	40,000
Unused remaining available borrowing capacity with FHLBB	$ 601,000	$ 449,900

Borrowings (Federal Home Loan B

Borrowings (Federal Home Loan Bank Advances Maturity Schedule) (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Federal Home Loan Bank, Advances, Branch of FHLBB Bank [Line Items]
Federal Home Loan Bank advances	$ 828,392	$ 791,356
Federal Home Loan Bank of Boston [Member]
Federal Home Loan Bank, Advances, Branch of FHLBB Bank [Line Items]
Scheduled maturity through the end of the current year	$ 297,670
Weighted average rate for scheduled maturity through the end of the current year	2.26%
Scheduled maturity in year two	$ 347,258
Weighted average rate for scheduled maturity in year two	2.15%
Scheduled maturity in year three	$ 67,033
Weighted average rate for scheduled maturity in year three	1.95%
Scheduled maturity in year four	$ 46,222
Weighted average rate for scheduled maturity in year four	2.57%
Scheduled maturity in year five	$ 55,447
Weighted average rate for scheduled maturity in year five	3.59%
Scheduled maturity after year five	$ 14,762
Weighted average rate for scheduled maturity after year five	2.29%
Federal Home Loan Bank advances	$ 828,392	$ 791,356
Total weighted average rate	2.35%

Shareholders' Equity (Regulator

Shareholders' Equity (Regulatory Captial Requirements) (Details) - USD ($) $ in Thousands		Sep. 30, 2018	Dec. 31, 2017
Corporation [Member]
Total Capital (to Risk-Weighted Assets):
Total Capital		$ 445,448	$ 416,038
Total Capital to Risk-Weighted Assets		12.77%	12.45%
Total Capital for Capital Adequacy Purposes		$ 279,165	$ 267,365
Total Capital for Capital Adequacy Purposes to Risk-Weighted Assets		8.00%	8.00%
Tier 1 Capital (to Risk-Weighted Assets):
Tier 1 Capital		$ 418,649	$ 389,289
Tier 1 Capital to Risk Weighted-Assets		12.00%	11.65%
Tier 1 Capital Required For Capital Adequacy Purposes		$ 209,374	$ 200,524
Tier 1 Capital Required for Capital Adequacy Purposes to Risk Weighted-Assets		6.00%	6.00%
Common Equity Tier 1 Capital [Abstract]
Common Equity Tier 1 Capital		$ 396,651	$ 367,291
Common Equity Tier 1 Capital to Risk Weighted Assets		11.37%	10.99%
Common Equity Tier 1 Capital Required for Capital Adequacy		$ 157,031	$ 150,383
Common Equity Tier 1 Capital for Capital Adequacy to Risk Weighted Assets		4.50%	4.50%
Tier 1 Capital (to Average Assets):
Tier 1 Leverage Capital	[1]	$ 418,649	$ 389,289
Tier 1 Leverage Capital to Average Assets	[1]	8.91%	8.79%
Tier 1 Leverage Capital Required for Capital Adequacy Purposes	[1]	$ 187,898	$ 177,089
Tier 1 Leverage Capital Required for Capital Adequacy Purposes to Average Assets	[1]	4.00%	4.00%
Bank [Member]
Total Capital (to Risk-Weighted Assets):
Total Capital		$ 442,337	$ 413,593
Total Capital to Risk-Weighted Assets		12.68%	12.38%
Total Capital for Capital Adequacy Purposes		$ 279,145	$ 267,338
Total Capital for Capital Adequacy Purposes to Risk-Weighted Assets		8.00%	8.00%
Total Capital To Be Well Capitalized		$ 348,931	$ 334,172
Total Capital To Be Well Capitalized to Risk Weighted-Assets		10.00%	10.00%
Tier 1 Capital (to Risk-Weighted Assets):
Tier 1 Capital		$ 415,538	$ 386,844
Tier 1 Capital to Risk Weighted-Assets		11.91%	11.58%
Tier 1 Capital Required For Capital Adequacy Purposes		$ 209,358	$ 200,503
Tier 1 Capital Required for Capital Adequacy Purposes to Risk Weighted-Assets		6.00%	6.00%
Tier 1 Capital Required To Be Well Capitalized		$ 279,145	$ 267,338
Tier 1 Capital Required To Be Well Capitalized to Risk Weighted-Assets		8.00%	8.00%
Common Equity Tier 1 Capital [Abstract]
Common Equity Tier 1 Capital		$ 415,538	$ 386,844
Common Equity Tier 1 Capital to Risk Weighted Assets		11.91%	11.58%
Common Equity Tier 1 Capital Required for Capital Adequacy		$ 157,019	$ 150,378
Common Equity Tier 1 Capital for Capital Adequacy to Risk Weighted Assets		4.50%	4.50%
Common Equity Tier 1 Capital Required to be Well Capitalized		$ 226,805	$ 217,212
Common Equity Tier 1 Capital Required to be Well Capitalized to Risk Weighted Assets		6.50%	6.50%
Tier 1 Capital (to Average Assets):
Tier 1 Leverage Capital	[1]	$ 415,538	$ 386,844
Tier 1 Leverage Capital to Average Assets	[1]	8.85%	8.74%
Tier 1 Leverage Capital Required for Capital Adequacy Purposes	[1]	$ 187,858	$ 177,048
Tier 1 Leverage Capital Required for Capital Adequacy Purposes to Average Assets	[1]	4.00%	4.00%
Tier 1 Leverage Capital Required To Be Well Capitalized	[1]	$ 234,822	$ 221,310
Tier 1 Leverage Capital Required To Be Well Capitalized to Average Assets	[1]	5.00%	5.00%
[1]	Leverage ratio.

Derivative Financial Instrume_3

Derivative Financial Instruments (Narrative) (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018USD ($)derivative_instrument	Sep. 30, 2017USD ($)	Sep. 30, 2018USD ($)derivative_instrument	Sep. 30, 2017USD ($)	Dec. 31, 2017USD ($)derivative_instrument
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Amount of ineffectiveness recorded in earnings	$ 0	$ 0	$ 0	$ 0
Interest rate swaps [Member]
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Notional amount	60,000		60,000		$ 60,000
Interest rate swaps with customers [Member]
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Notional amount	574,364		574,364		545,049
Mirror swaps with counterparties [Member]
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Notional amount	574,364		574,364		545,049
Risk participation-in agreement [Member]
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Notional amount	36,610		36,610		34,052
Foreign exchange contracts [Member]
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Notional amount	$ 2,907		$ 2,907		$ 3,005
Derivatives Designated as Cash Flow Hedging Instruments [Member] | Interest rate caps [Member]
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Number of instruments held | derivative_instrument	2		2		2
Notional amount	$ 22,700		$ 22,700		$ 22,700
Interest rate cap interest rate	4.50%		4.50%		4.50%
Derivatives Designated as Cash Flow Hedging Instruments [Member] | Interest rate swaps [Member]
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Number of instruments held | derivative_instrument	2		2		2
Notional amount	$ 60,000		$ 60,000		$ 60,000
Derivatives Designated as Cash Flow Hedging Instruments [Member] | Interest rate floors [Member]
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Number of instruments held | derivative_instrument	3		3		3
Notional amount	$ 300,000		$ 300,000		$ 300,000
Interest rate floor interest rate	1.00%		1.00%		1.00%
Not Designated as Hedging Instrument [Member] | Interest rate swaps with customers [Member]
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Notional amount	$ 574,400		$ 574,400		$ 545,000
Not Designated as Hedging Instrument [Member] | Mirror swaps with counterparties [Member]
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Notional amount	574,400		574,400		545,000
Not Designated as Hedging Instrument [Member] | Risk participation-out agreement [Member]
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Notional amount	51,500		51,500		52,400
Not Designated as Hedging Instrument [Member] | Risk participation-in agreement [Member]
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Notional amount	36,600		36,600		34,100
Not Designated as Hedging Instrument [Member] | Foreign exchange contracts [Member]
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Notional amount	$ 2,900		$ 2,900		$ 3,000

Derivative Financial Instrume_4

Derivative Financial Instruments (Fair Value of Derivatives by Balance Sheet Location) (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Derivatives, Fair Value [Line Items]
Total derivative assets	$ 20,242	$ 2,759
Total derivative liabilities	17,822	3,047
Other assets [Member]
Derivatives, Fair Value [Line Items]
Total derivative assets	20,242	2,759
Other liabilities [Member]
Derivatives, Fair Value [Line Items]
Total derivative liabilities	17,822	3,047
Derivatives Designated as Cash Flow Hedging Instruments [Member] | Interest rate caps [Member] | Other assets [Member]
Derivatives, Fair Value [Line Items]
Derivative asset designated as a cash flow hedge	83	25
Derivatives Designated as Cash Flow Hedging Instruments [Member] | Interest rate caps [Member] | Other liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative liability designated as a cash flow hedge	0	0
Derivatives Designated as Cash Flow Hedging Instruments [Member] | Interest rate swaps [Member] | Other assets [Member]
Derivatives, Fair Value [Line Items]
Derivative asset designated as a cash flow hedge	1,947	213
Derivatives Designated as Cash Flow Hedging Instruments [Member] | Interest rate swaps [Member] | Other liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative liability designated as a cash flow hedge	0	14
Derivatives Designated as Cash Flow Hedging Instruments [Member] | Interest rate floors [Member] | Other assets [Member]
Derivatives, Fair Value [Line Items]
Derivative asset designated as a cash flow hedge	14	110
Derivatives Designated as Cash Flow Hedging Instruments [Member] | Interest rate floors [Member] | Other liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative liability designated as a cash flow hedge	0	0
Not Designated as Hedging Instrument [Member] | Interest rate swaps with customers [Member] | Other assets [Member]
Derivatives, Fair Value [Line Items]
Derivative asset not designated	33	268
Not Designated as Hedging Instrument [Member] | Interest rate swaps with customers [Member] | Other liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative liability not designated	17,522	1,295
Not Designated as Hedging Instrument [Member] | Mirror swaps with counterparties [Member] | Other assets [Member]
Derivatives, Fair Value [Line Items]
Derivative asset not designated	17,342	1,152
Not Designated as Hedging Instrument [Member] | Mirror swaps with counterparties [Member] | Other liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative liability not designated	33	268
Not Designated as Hedging Instrument [Member] | Risk participation agreements [Member] | Other assets [Member]
Derivatives, Fair Value [Line Items]
Derivative asset not designated	0	0
Not Designated as Hedging Instrument [Member] | Risk participation agreements [Member] | Other liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative liability not designated	0	0
Not Designated as Hedging Instrument [Member] | Foreign exchange contracts [Member] | Other assets [Member]
Derivatives, Fair Value [Line Items]
Derivative asset not designated	37	0
Not Designated as Hedging Instrument [Member] | Foreign exchange contracts [Member] | Other liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative liability not designated	0	26
Not Designated as Hedging Instrument [Member] | Interest rate lock commitments [Member] | Other assets [Member]
Derivatives, Fair Value [Line Items]
Derivative asset not designated	618	965
Not Designated as Hedging Instrument [Member] | Interest rate lock commitments [Member] | Other liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative liability not designated	1	20
Not Designated as Hedging Instrument [Member] | Forward sale commitments [Member] | Other assets [Member]
Derivatives, Fair Value [Line Items]
Derivative asset not designated	168	26
Not Designated as Hedging Instrument [Member] | Forward sale commitments [Member] | Other liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative liability not designated	$ 266	$ 1,424

Derivative Financial Instrume_5

Derivative Financial Instruments (Derivatives in Cash Flow Hedging Relationships, Effect in Statements of Income and Changes in Shareholders' Equity) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Recognized in Other Comprehensive Income (Effective Portion)	$ 155	$ (13)	$ 1,409	$ (364)
Interest rate caps [Member] | Cash Flow Hedge [Member] | Other Comprehensive Income (Loss) [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Recognized in Other Comprehensive Income (Effective Portion)	17	(7)	66	(64)
Interest rate swaps [Member] | Cash Flow Hedge [Member] | Other Comprehensive Income (Loss) [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Recognized in Other Comprehensive Income (Effective Portion)	189	74	1,322	(26)
Interest rate floors [Member] | Cash Flow Hedge [Member] | Other Comprehensive Income (Loss) [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Recognized in Other Comprehensive Income (Effective Portion)	$ (51)	$ (80)	$ 21	$ (274)

Derivative Financial Instrume_6

Derivative Financial Instruments (Derivatives not Designated as Hedging Instruments, Effect in Statements of Income) (Details) - Not Designated as Hedging Instrument [Member] - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Recognized in Income	$ 90	$ 1,543	$ 2,312	$ 2,062
Interest rate swaps with customers [Member] | Loan related derivative income [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Recognized in Income	(3,178)	1,917	(15,374)	5,583
Mirror swaps with counterparties [Member] | Loan related derivative income [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Recognized in Income	3,415	(505)	16,384	(2,578)
Risk participation agreements [Member] | Loan related derivative income [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Recognized in Income	25	40	25	(261)
Foreign exchange contracts [Member] | Loan related derivative income [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Recognized in Income	16	0	52	0
Interest rate lock commitments [Member] | Mortgage banking revenues [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Recognized in Income	(504)	32	(327)	639
Forward sale commitments [Member] | Mortgage banking revenues [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Recognized in Income	$ 316	$ 59	$ 1,552	$ (1,321)

Balance Sheet Offsetting (Detai

Balance Sheet Offsetting (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Other assets [Member]
Gross derivative positions	$ 20,328	$ 7,006
Offsetting derivative positions	872	5,238
Net amounts presented in balance sheet	19,456	1,768
Cash collateral pledged	0	0
Net amount	19,456	1,768
Other assets [Member] | Interest rate floors [Member]
Gross derivative positions	14	110
Offsetting derivative positions	0	0
Net amounts presented in balance sheet	14	110
Cash collateral pledged	0	0
Net amount	14	110
Other assets [Member] | Interest rate caps [Member]
Gross derivative positions	83	25
Offsetting derivative positions	0	0
Net amounts presented in balance sheet	83	25
Cash collateral pledged	0	0
Net amount	83	25
Other assets [Member] | Interest rate swaps [Member]
Gross derivative positions	1,947	213
Offsetting derivative positions	0	0
Net amounts presented in balance sheet	1,947	213
Cash collateral pledged	0	0
Net amount	1,947	213
Other assets [Member] | Interest rate swaps with customers [Member]
Gross derivative positions	463	2,857
Offsetting derivative positions	430	2,589
Net amounts presented in balance sheet	33	268
Cash collateral pledged	0	0
Net amount	33	268
Other assets [Member] | Mirror swaps with counterparties [Member]
Gross derivative positions	17,784	3,801
Offsetting derivative positions	442	2,649
Net amounts presented in balance sheet	17,342	1,152
Cash collateral pledged	0	0
Net amount	17,342	1,152
Other assets [Member] | Foreign exchange contracts [Member]
Gross derivative positions	37
Offsetting derivative positions	0
Net amounts presented in balance sheet	37
Cash collateral pledged	0
Net amount	37
Other liabilities [Member]
Gross derivative positions	18,427	6,841
Offsetting derivative positions	872	5,238
Net amounts presented in balance sheet	17,555	1,603
Cash collateral pledged	0	1,039
Net amount	17,555	564
Other liabilities [Member] | Interest rate swaps [Member]
Gross derivative positions		14
Offsetting derivative positions		0
Net amounts presented in balance sheet		14
Cash collateral pledged		14
Net amount		0
Other liabilities [Member] | Interest rate swaps with customers [Member]
Gross derivative positions	17,952	3,884
Offsetting derivative positions	430	2,589
Net amounts presented in balance sheet	17,522	1,295
Cash collateral pledged	0	1,025
Net amount	17,522	270
Other liabilities [Member] | Mirror swaps with counterparties [Member]
Gross derivative positions	475	2,917
Offsetting derivative positions	442	2,649
Net amounts presented in balance sheet	33	268
Cash collateral pledged	0	0
Net amount	$ 33	268
Other liabilities [Member] | Foreign exchange contracts [Member]
Gross derivative positions		26
Offsetting derivative positions		0
Net amounts presented in balance sheet		26
Cash collateral pledged		0
Net amount		$ 26

Fair Value Measurements (Narrat

Fair Value Measurements (Narrative) (Details) - USD ($) $ in Thousands	Aug. 01, 2015	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Payment of contingent consideration liability		$ 0	$ 0	$ (1,217)	$ 0
Nonrecurring [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Allowance For Loan Loss Allocation on Collateral Dependent Impaired Loans		$ 8		$ 8		$ 690
Contingent Consideration [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Earn-out period post acquisition	5 years

Fair Value Measurements (Fair V

Fair Value Measurements (Fair Value Mortgage Loans Held For Sale Disclosures) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Mortgage loans held for sale, amortized cost	$ 22,300		$ 22,300		$ 26,400
Mortgage loans held for sale, measured at fair value	22,600		22,600		26,900
Mortgage loans held for sale, difference between fair value and amortized cost	303		303		$ 543
Mortgage Loans Held for Sale [Member]
Change in fair value under fair value option election	$ (352)	$ (81)	$ (240)	$ 693

Fair Value Measurements (Assets

Fair Value Measurements (Assets and Liabilities Measured at Fair Value on a Recurring Basis) (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Jun. 30, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale securities	$ 812,647		$ 780,954
Mortgage loans held for sale, measured at fair value	22,600		26,900
Derivative assets	20,242		2,759
Derivative liabilities	17,822		3,047
Contingent consideration liability	187	$ 187	1,404	$ 1,737	$ 1,737	$ 2,047
Obligations of U.S. government-sponsored enterprises [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale securities	193,473		157,604
Mortgage-backed securities issued by U.S. government-sponsored agencies and U.S. government-sponsored enterprises [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale securities	592,862		590,882
Obligations of states and political subdivisions [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale securities	937		2,359
Individual name issuer trust preferred debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale securities	12,464		16,984
Corporate bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale securities	12,911		13,125
Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	0		0
Derivative liabilities	0		0
Contingent consideration liability	0		0
Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	20,242		2,759
Derivative liabilities	17,822		3,047
Contingent consideration liability	0		0
Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	0		0
Derivative liabilities	0		0
Contingent consideration liability	187		1,404
Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage loans held for sale, measured at fair value	22,571		26,943
Total assets at fair value on a recurring basis	855,460		810,656
Total liabilities at fair value on a recurring basis	18,009		4,451
Recurring [Member] | Obligations of U.S. government-sponsored enterprises [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale securities	193,473		157,604
Recurring [Member] | Mortgage-backed securities issued by U.S. government-sponsored agencies and U.S. government-sponsored enterprises [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale securities	592,862		590,882
Recurring [Member] | Obligations of states and political subdivisions [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale securities	937		2,359
Recurring [Member] | Individual name issuer trust preferred debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale securities	12,464		16,984
Recurring [Member] | Corporate bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale securities	12,911		13,125
Recurring [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage loans held for sale, measured at fair value	0		0
Total assets at fair value on a recurring basis	0		0
Total liabilities at fair value on a recurring basis	0		0
Recurring [Member] | Level 1 [Member] | Obligations of U.S. government-sponsored enterprises [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale securities	0		0
Recurring [Member] | Level 1 [Member] | Mortgage-backed securities issued by U.S. government-sponsored agencies and U.S. government-sponsored enterprises [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale securities	0		0
Recurring [Member] | Level 1 [Member] | Obligations of states and political subdivisions [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale securities	0		0
Recurring [Member] | Level 1 [Member] | Individual name issuer trust preferred debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale securities	0		0
Recurring [Member] | Level 1 [Member] | Corporate bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale securities	0		0
Recurring [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage loans held for sale, measured at fair value	22,571		26,943
Total assets at fair value on a recurring basis	855,460		810,656
Total liabilities at fair value on a recurring basis	17,822		3,047
Recurring [Member] | Level 2 [Member] | Obligations of U.S. government-sponsored enterprises [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale securities	193,473		157,604
Recurring [Member] | Level 2 [Member] | Mortgage-backed securities issued by U.S. government-sponsored agencies and U.S. government-sponsored enterprises [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale securities	592,862		590,882
Recurring [Member] | Level 2 [Member] | Obligations of states and political subdivisions [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale securities	937		2,359
Recurring [Member] | Level 2 [Member] | Individual name issuer trust preferred debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale securities	12,464		16,984
Recurring [Member] | Level 2 [Member] | Corporate bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale securities	12,911		13,125
Recurring [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage loans held for sale, measured at fair value	0		0
Total assets at fair value on a recurring basis	0		0
Total liabilities at fair value on a recurring basis	187		1,404
Recurring [Member] | Level 3 [Member] | Obligations of U.S. government-sponsored enterprises [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale securities	0		0
Recurring [Member] | Level 3 [Member] | Mortgage-backed securities issued by U.S. government-sponsored agencies and U.S. government-sponsored enterprises [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale securities	0		0
Recurring [Member] | Level 3 [Member] | Obligations of states and political subdivisions [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale securities	0		0
Recurring [Member] | Level 3 [Member] | Individual name issuer trust preferred debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale securities	0		0
Recurring [Member] | Level 3 [Member] | Corporate bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale securities	$ 0		$ 0

Fair Value Measurements Fair Va

Fair Value Measurements Fair Value Measurements (Change in Contingent Consideration) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of period	$ 187	$ 1,737	$ 1,404	$ 2,047
Change in fair value of contingent consideration	0	0	0	(310)
Payments	0	0	(1,217)	0
Balance at end of period	$ 187	$ 1,737	$ 187	$ 1,737

Fair Value Measurements (Asset

Fair Value Measurements (Asset and Liabilities Measured on a Nonrecurring Basis) (Details) - USD ($) $ in Thousands		Sep. 30, 2018	Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	[1]	$ 821	$ 5,993
Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans		27	1,425
Property acquired through foreclosure or repossession		2,974	131
Total assets at fair value on a nonrecurring basis		3,001	1,556
Nonrecurring [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans		0	0
Property acquired through foreclosure or repossession		0	0
Total assets at fair value on a nonrecurring basis		0	0
Nonrecurring [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans		0	0
Property acquired through foreclosure or repossession		0	0
Total assets at fair value on a nonrecurring basis		0	0
Nonrecurring [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans		27	1,425
Property acquired through foreclosure or repossession		2,974	131
Total assets at fair value on a nonrecurring basis		$ 3,001	$ 1,556
[1]	The recorded investment in impaired loans consists of unpaid principal balance, net of charge-offs, interest payments received applied to principal and unamortized deferred loan origination fees and costs. For accruing impaired loans (troubled debt restructurings for which management has concluded that the collectibility of the loan is not in doubt), the recorded investment also includes accrued interest.

Fair Value Measurements (Qualit

Fair Value Measurements (Qualitative Information About Level 3 Assets Measured at Fair Value on a Nonrecurring Basis) (Details) - USD ($) $ in Thousands		9 Months Ended
		Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Collateral dependent impaired loans	[1]	$ 821		$ 5,993
Nonrecurring [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Collateral dependent impaired loans		27		1,425
Property acquired through foreclosure or repossession		2,974		131
Nonrecurring [Member] | Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Collateral dependent impaired loans		27		1,425
Property acquired through foreclosure or repossession		$ 2,974		$ 131
Nonrecurring [Member] | Minimum [Member] | Collateral Dependent Impaired Loans [Member] | Appraisals Of Collateral [Member] | Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Discount for costs to sell		0.00%	0.00%
Nonrecurring [Member] | Minimum [Member] | Property Acquired Through Foreclosure Or Repossession [Member] | Appraisals Of Collateral [Member] | Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Discount for costs to sell		13.00%	10.00%
Appraisal adjustments	[2]	12.00%	12.00%
Nonrecurring [Member] | Maximum [Member] | Collateral Dependent Impaired Loans [Member] | Appraisals Of Collateral [Member] | Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Discount for costs to sell		10.00%	15.00%
Nonrecurring [Member] | Maximum [Member] | Property Acquired Through Foreclosure Or Repossession [Member] | Appraisals Of Collateral [Member] | Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Discount for costs to sell		13.00%	10.00%
Appraisal adjustments	[2]	12.00%	17.00%
Nonrecurring [Member] | Weighted Average [Member] | Collateral Dependent Impaired Loans [Member] | Appraisals Of Collateral [Member] | Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Discount for costs to sell		8.00%	15.00%
Nonrecurring [Member] | Weighted Average [Member] | Property Acquired Through Foreclosure Or Repossession [Member] | Appraisals Of Collateral [Member] | Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Discount for costs to sell		13.00%	10.00%
Appraisal adjustments	[2]	12.00%	15.00%
[1]	The recorded investment in impaired loans consists of unpaid principal balance, net of charge-offs, interest payments received applied to principal and unamortized deferred loan origination fees and costs. For accruing impaired loans (troubled debt restructurings for which management has concluded that the collectibility of the loan is not in doubt), the recorded investment also includes accrued interest.
[2]	Management may adjust appraisal values to reflect market value declines or other discounts resulting from its knowledge of the property.

Fair Value Measurements (Carryi

Fair Value Measurements (Carrying Amounts and Estimated Fair Values of Financial Instruments) (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held to maturity securities	$ 10,863	$ 12,541
Loans, net of allowance of loan losses	3,529,694	3,347,583
Federal Home Loan Bank advances	828,392	791,356
Junior subordinated debentures	22,681	22,681
Reported Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held to maturity securities	10,863	12,541
Loans, net of allowance of loan losses	3,529,694	3,347,583
Time deposits	1,159,218	1,015,095
Federal Home Loan Bank advances	828,392	791,356
Junior subordinated debentures	22,681	22,681
Fair Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held to maturity securities	10,657	12,721
Loans, net of allowance of loan losses	3,500,065	3,369,932
Time deposits	1,170,151	1,018,396
Federal Home Loan Bank advances	827,328	792,887
Junior subordinated debentures	19,844	18,559
Fair Value Measurement [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held to maturity securities	0	0
Loans, net of allowance of loan losses	0	0
Time deposits	0	0
Federal Home Loan Bank advances	0	0
Junior subordinated debentures	0	0
Fair Value Measurement [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held to maturity securities	10,657	12,721
Loans, net of allowance of loan losses	0	0
Time deposits	1,170,151	1,018,396
Federal Home Loan Bank advances	827,328	792,887
Junior subordinated debentures	19,844	18,559
Fair Value Measurement [Member] | Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held to maturity securities	0	0
Loans, net of allowance of loan losses	3,500,065	3,369,932
Time deposits	0	0
Federal Home Loan Bank advances	0	0
Junior subordinated debentures	$ 0	$ 0

Revenue from Contracts with C_4

Revenue from Contracts with Customers (Narrative) (Details) - USD ($) $ in Millions	Sep. 30, 2018	Dec. 31, 2017
Revenue from Contract with Customer [Abstract]
Receivables from contracts with customers	$ 5.2	$ 5.7

Revenue from Contracts with C_5

Revenue from Contracts with Customers (Disaggregation of Revenue) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Net interest income	$ 33,449	$ 30,059	$ 98,412	$ 88,642
Asset-based wealth management revenues	9,322	9,791	28,413	28,439
Transaction-based wealth management revenues	132	222	916	993
Wealth management revenues	9,454	10,013	29,329	29,432
Mortgage banking revenues	2,624	3,036	8,403	8,295
Service charges on deposit accounts	885	942	2,651	2,726
Card interchange fees	983	894	2,791	2,598
Income from bank-owned life insurance	572	546	1,624	1,624
Loan related derivative income	278	1,452	1,087	2,744
Other income	419	400	1,066	1,180
Total noninterest income	15,215	17,283	46,951	48,599
Total revenues	48,664	47,342	145,363	137,241
Revenue from Contracts with Customers [Member]
Net interest income	0	0	0	0
Asset-based wealth management revenues	9,322	9,791	28,413	28,439
Transaction-based wealth management revenues	132	222	916	993
Wealth management revenues	9,454	10,013	29,329	29,432
Mortgage banking revenues	0	0	0	0
Service charges on deposit accounts	885	942	2,651	2,726
Card interchange fees	983	894	2,791	2,598
Income from bank-owned life insurance	0	0	0	0
Loan related derivative income	0	0	0	0
Other income	419	400	1,051	1,139
Total noninterest income	11,741	12,249	35,822	35,895
Total revenues	$ 11,741	$ 12,249	$ 35,822	$ 35,895

Revenue from Contracts with C_6

Revenue from Contracts with Customers (Disaggregation by Timing of Revenue Recognition) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Wealth management revenues	$ 9,454	$ 10,013	$ 29,329	$ 29,432
Card interchange fees	983	894	2,791	2,598
Service charges on deposit accounts	885	942	2,651	2,726
Other income	419	400	1,066	1,180
Total revenues	48,664	47,342	145,363	137,241
Revenue from Contracts with Customers [Member]
Wealth management revenues	9,454	10,013	29,329	29,432
Card interchange fees	983	894	2,791	2,598
Service charges on deposit accounts	885	942	2,651	2,726
Other income	419	400	1,051	1,139
Total revenues	11,741	12,249	35,822	35,895
Transferred at Point in Time [Member] | Revenue from Contracts with Customers [Member]
Card interchange fees	983	894	2,791	2,598
Service charges on deposit accounts	670	741	2,045	2,140
Other income	258	283	732	872
Transferred over Time [Member] | Revenue from Contracts with Customers [Member]
Wealth management revenues	9,454	10,013	29,329	29,432
Service charges on deposit accounts	215	201	606	586
Other income	$ 161	$ 117	$ 319	$ 267

Defined Benefit Pension Plans_2

Defined Benefit Pension Plans (Narrative) (Details) - USD ($) $ in Millions	120 Months Ended
	Dec. 30, 2023	Sep. 30, 2018	Dec. 31, 2017
Scenario, Forecast [Member]
Transition Period Pension Plan Amendment	10 years
Non-Qualified Retirement Plans [Member]
Available-for-sale Securities and Other Short-term Investments, Rabbi Trusts		$ 12.5	$ 13.3

Defined Benefit Pension Plans_3

Defined Benefit Pension Plans (Components of Net Periodic Benefit Cost) (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Qualified Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	[1]	$ 561	$ 537	$ 1,683	$ 1,611
Interest cost	[2]	679	669	2,036	2,005
Expected return on plan assets	[2]	(1,318)	(1,236)	(3,954)	(3,707)
Amortization of prior service (credit) cost	[2]	(6)	(6)	(17)	(17)
Recognized net actuarial loss	[2]	374	279	1,122	836
Net periodic benefit cost		290	243	870	728
Non-Qualified Retirement Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	[1]	27	32	81	97
Interest cost	[2]	119	107	356	321
Expected return on plan assets	[2]	0	0	0	0
Amortization of prior service (credit) cost	[2]	0	0	0	0
Recognized net actuarial loss	[2]	103	76	308	269
Net periodic benefit cost		$ 249	$ 215	$ 745	$ 687
[1]	Included in salaries and employee benefits expense in the Unaudited Consolidated Statements of Income.
[2]	Included in other expenses in the Unaudited Consolidated Statements of Income.

Defined Benefit Pension Plans_4

Defined Benefit Pension Plans (Weighted-Average Assumptions Used) (Details)	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Qualified Pension Plan [Member]
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Equivalent single discount rate for benefit obligations	3.69%	4.18%
Equivalent single discount rate for service cost	3.76%	4.29%
Equivalent single discount rate for interest cost	3.42%	3.73%
Expected long-term return on plan assets	6.75%	6.75%
Rate of compensation increase	3.75%	3.75%
Non-Qualified Retirement Plans [Member]
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Equivalent single discount rate for benefit obligations	3.58%	3.96%
Equivalent single discount rate for service cost	3.79%	4.25%
Equivalent single discount rate for interest cost	3.22%	3.36%
Rate of compensation increase	3.75%	3.75%

Share-Based Compensation (Narra

Share-Based Compensation (Narrative) (Details)	9 Months Ended
	Sep. 30, 2018$ / sharesshares
Performance Based Nonvested Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance share awards, minimum target percentage	0.00%
Performance share awards, maximum target percentage	200.00%
Time Based Nonvested Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Nonvested share units granted | shares	6,830
Nonvested share units weighted average grant date fair value | $ / shares	$ 56.65
Minimum [Member] | Performance Based Nonvested Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period	3 years
Minimum [Member] | Time Based Nonvested Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period	3 years
Maximum [Member] | Performance Based Nonvested Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period	5 years
Maximum [Member] | Time Based Nonvested Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period	5 years
2018 Grant [Member] | Performance Based Nonvested Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance share awards, grant date fair value | $ / shares	$ 54.25
Performance share awards, shares vesting percentage	140.00%
Performance share awards, shares vesting | shares	41,454

Business Segments (Statement of

Business Segments (Statement of Operations and Total Assets by Reportable Segment) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Segment Reporting Information [Line Items]
Net interest income (expense)	$ 33,449	$ 30,059	$ 98,412	$ 88,642
Provision for loan losses	350	1,300	750	2,400
Net interest income after provision for loan losses	33,099	28,759	97,662	86,242
Noninterest income	15,215	17,283	46,951	48,599
Depreciation and amortization expense	1,069	1,107	3,194	3,400
Other noninterest expenses related to segments	24,993	25,647	76,286	74,946
Total noninterest expense	26,062	26,754	79,480	78,346
Income before income taxes	22,252	19,288	65,133	56,495
Income tax expense	4,741	6,326	13,737	18,552
Net income	17,511	12,962	51,396	37,943
Total assets	4,770,672	4,469,230	4,770,672	4,469,230	$ 4,529,850
Expenditures for long-lived assets	645	937	2,320	2,184
Commercial Banking [Member]
Segment Reporting Information [Line Items]
Net interest income (expense)	27,036	24,795	79,656	72,985
Provision for loan losses	350	1,300	750	2,400
Net interest income after provision for loan losses	26,686	23,495	78,906	70,585
Noninterest income	5,174	6,711	15,947	17,500
Depreciation and amortization expense	654	646	1,928	1,960
Other noninterest expenses related to segments	15,599	15,834	46,574	45,764
Total noninterest expense	16,253	16,480	48,502	47,724
Income before income taxes	15,607	13,726	46,351	40,361
Income tax expense	3,344	4,463	9,834	13,142
Net income	12,263	9,263	36,517	27,219
Total assets	3,694,991	3,486,783	3,694,991	3,486,783
Expenditures for long-lived assets	612	890	1,864	1,640
Wealth Management Services [Member]
Segment Reporting Information [Line Items]
Net interest income (expense)	(90)	(48)	(225)	(120)
Provision for loan losses	0	0	0	0
Net interest income after provision for loan losses	(90)	(48)	(225)	(120)
Noninterest income	9,454	10,013	29,329	29,432
Depreciation and amortization expense	371	411	1,137	1,288
Other noninterest expenses related to segments	6,194	6,810	19,986	20,106
Total noninterest expense	6,565	7,221	21,123	21,394
Income before income taxes	2,799	2,744	7,981	7,918
Income tax expense	710	1,092	2,008	3,172
Net income	2,089	1,652	5,973	4,746
Total assets	69,494	63,600	69,494	63,600
Expenditures for long-lived assets	14	25	327	368
Corporate [Member]
Segment Reporting Information [Line Items]
Net interest income (expense)	6,503	5,312	18,981	15,777
Provision for loan losses	0	0	0	0
Net interest income after provision for loan losses	6,503	5,312	18,981	15,777
Noninterest income	587	559	1,675	1,667
Depreciation and amortization expense	44	50	129	152
Other noninterest expenses related to segments	3,200	3,003	9,726	9,076
Total noninterest expense	3,244	3,053	9,855	9,228
Income before income taxes	3,846	2,818	10,801	8,216
Income tax expense	687	771	1,895	2,238
Net income	3,159	2,047	8,906	5,978
Total assets	1,006,187	918,847	1,006,187	918,847
Expenditures for long-lived assets	$ 19	$ 22	$ 129	$ 176

Other Comprehensive Income (L_3

Other Comprehensive Income (Loss) (Activity in Other Comprehensive Income) (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent [Abstract]
Changes in fair value of securities available for sale, before tax		$ (5,924)	$ 1,736	$ (23,605)	$ 5,274
Changes in fair value of securities available for sale, tax		(1,393)	642	(5,548)	1,951
Changes in fair value of securities available for sale		(4,531)	1,094	(18,057)	3,323
Net gains on securities reclassified into earnings, before tax		0	0	0	0
Net gains on securities reclassified into earnings, tax		0	0	0	0
Net gains on securities reclassified into earnings		0	0	0	0
Net change in fair value of securities available for sale, before tax		(5,924)	1,736	(23,605)	5,274
Net change in fair value of securities available for sale, tax		(1,393)	642	(5,548)	1,951
Net change in fair value of securities available for sale		(4,531)	1,094	(18,057)	3,323
Change in fair value of cash flow hedges, before tax		(626)	(237)	632	(1,064)
Change in fair value of cash flow hedges, tax		(148)	(83)	50	(361)
Change in fair value of cash flow hedges		(478)	(154)	582	(703)
Net cash flow hedge losses reclassified into earnings, before tax	[1]	830	224	1,082	539
Net cash flow hedge losses reclassified into earnings, tax	[1]	197	83	255	200
Net cash flow hedge losses reclassified into earnings	[1]	633	141	827	339
Net change in fair value of cash flow hedges, before tax		204	(13)	1,714	(525)
Net change in fair value of cash flow hedges, tax		49	0	305	(161)
Net change in fair value of cash flow hedges		155	(13)	1,409	(364)
Defined benefit plan obligation adjustment, before tax		0	0	0	(407)
Defined benefit plan obligation adjustment, tax		0	0	0	(150)
Defined benefit plan obligation adjustment		0	0	0	(257)
Amortization of net actuarial losses, before tax	[2]	477	355	1,430	1,105
Amortization of net actuarial losses, tax	[2]	112	134	337	411
Amortization of net actuarial losses	[2]	365	221	1,093	694
Amortization of net prior service credits, before tax	[2]	(6)	(6)	(17)	(17)
Amortization of net prior service credits, tax	[2]	(2)	(2)	(5)	(7)
Amortization of net prior service credits	[2]	(4)	(4)	(12)	(10)
Net change in defined benefit plan obligations, before tax		471	349	1,413	681
Net change in defined benefit plan obligations, tax		110	132	332	254
Net change in defined benefit plan obligations		361	217	1,081	427
Total other comprehensive income (loss), before tax		(5,249)	2,072	(20,478)	5,430
Total other comprehensive income (loss), tax		(1,234)	774	(4,911)	2,044
Total other comprehensive income (loss), net of tax		$ (4,015)	$ 1,298	$ (15,567)	$ 3,386
[1]	The pre-tax amounts are included in interest expense on FHLB advances, interest expense on junior subordinated debentures and interest and fees on loans in the Unaudited Consolidated Statements of Income.
[2]	The pre-tax amounts are included in other expenses in the Unaudited Consolidated Statements of Income.

Other Comprehensive Income (L_4

Other Comprehensive Income (Loss) (Components of Accumulated Other Comprehensive Income) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Accumulated other comprehensive income (loss), beginning balance			$ (23,510)	$ (19,757)
Other comprehensive income (loss) before reclassifications			(17,475)	2,620
Amounts reclassed from accumulated other comprehensive income (loss)			1,908	766
Total other comprehensive income (loss), net of tax	$ (4,015)	$ 1,298	(15,567)	3,386
Accumulated other comprehensive income (loss), ending balance	(39,077)	(16,371)	(39,077)	(16,371)
Net Unrealized Gains (Losses) on AFS Securities [Member]
Accumulated other comprehensive income (loss), beginning balance			(7,534)	(6,825)
Other comprehensive income (loss) before reclassifications			(18,057)	3,323
Amounts reclassed from accumulated other comprehensive income (loss)			0	0
Total other comprehensive income (loss), net of tax			(18,057)	3,323
Accumulated other comprehensive income (loss), ending balance	(25,591)	(3,502)	(25,591)	(3,502)
Net Unrealized Losses on Cash Flow Hedges [Member]
Accumulated other comprehensive income (loss), beginning balance			(428)	(300)
Other comprehensive income (loss) before reclassifications			582	(703)
Amounts reclassed from accumulated other comprehensive income (loss)			827	339
Total other comprehensive income (loss), net of tax			1,409	(364)
Accumulated other comprehensive income (loss), ending balance	981	(664)	981	(664)
Pension Benefit Adjustment [Member]
Accumulated other comprehensive income (loss), beginning balance			(15,548)	(12,632)
Other comprehensive income (loss) before reclassifications			0	0
Amounts reclassed from accumulated other comprehensive income (loss)			1,081	427
Total other comprehensive income (loss), net of tax			1,081	427
Accumulated other comprehensive income (loss), ending balance	$ (14,467)	$ (12,205)	$ (14,467)	$ (12,205)

Earning Per Common Share (Calcu

Earning Per Common Share (Calculation of Earnings Per Share) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Earnings Per Share [Abstract]
Net income	$ 17,511	$ 12,962	$ 51,396	$ 37,943
Less dividends and undistributed earnings allocated to participating securities	(36)	(28)	(112)	(84)
Net income applicable to common shareholders	$ 17,475	$ 12,934	$ 51,284	$ 37,859
Weighted average common shares outstanding - basic	17,283,000	17,212,000	17,263,000	17,201,000
Basic earnings per common share	$ 1.01	$ 0.75	$ 2.97	$ 2.20
Less dividends and undistributed earnings allocated to participating securities	$ (36)	$ (28)	$ (112)	$ (84)
Net income applicable to common shareholders	$ 17,475	$ 12,934	$ 51,284	$ 37,859
Dilutive effect of common stock equivalents	99,000	106,000	129,000	119,000
Weighted average common shares outstanding - diluted	17,382,000	17,318,000	17,392,000	17,320,000
Diluted earnings per common share	$ 1.01	$ 0.75	$ 2.95	$ 2.19
Antidilutive common stock equivalents	41,525		46,692	0

Commitments and Contingencies_2

Commitments and Contingencies (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Commitments and Contingencies Disclosure [Line Items]
Operating leases rental expense	$ 1,100	$ 1,100	$ 3,200	$ 3,300
Minimum [Member]
Commitments and Contingencies Disclosure [Line Items]
Lease expiration period			8 months
Lease expiration period, renewal option			1 year
Maximum [Member]
Commitments and Contingencies Disclosure [Line Items]
Lease expiration period			22 years
Lease expiration period, renewal option			5 years
Commitments to extend credit on standby letters of credit [Member] | Commitments to extend credit [Member]
Commitments and Contingencies Disclosure [Line Items]
Contract amount	$ 7,993		$ 7,993		$ 6,666

Commitments and Contingencies_3

Commitments and Contingencies (Financial Instruments with Off Balance Sheet Risk) (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Interest rate lock commitments [Member]
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Notional amount	$ 38,612	$ 45,139
Forward sale commitments [Member]
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Notional amount	65,686	71,539
Interest rate swaps with customers [Member]
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Notional amount	574,364	545,049
Mirror swaps with counterparties [Member]
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Notional amount	574,364	545,049
Risk participation-in agreement [Member]
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Notional amount	36,610	34,052
Foreign exchange contracts [Member]
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Notional amount	2,907	3,005
Interest rate swaps [Member]
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Notional amount	60,000	60,000
Commitments to extend credit on commerical loans [Member] | Commitments to extend credit [Member]
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Contract amount	519,887	537,310
Commitments to extend credit on home equity lines [Member] | Commitments to extend credit [Member]
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Contract amount	266,886	254,855
Commitments to extend credit on other loans [Member] | Commitments to extend credit [Member]
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Contract amount	44,665	48,819
Commitments to extend credit on standby letters of credit [Member] | Commitments to extend credit [Member]
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Contract amount	7,993	6,666
Not Designated as Hedging Instrument [Member] | Interest rate swaps with customers [Member]
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Notional amount	574,400	545,000
Not Designated as Hedging Instrument [Member] | Mirror swaps with counterparties [Member]
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Notional amount	574,400	545,000
Not Designated as Hedging Instrument [Member] | Risk participation-in agreement [Member]
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Notional amount	36,600	34,100
Not Designated as Hedging Instrument [Member] | Foreign exchange contracts [Member]
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Notional amount	$ 2,900	$ 3,000

Commitments and Contingencies_4

Commitments and Contingencies (Schedule of Future Minimum Operating Lease Payments) (Details) $ in Thousands	Sep. 30, 2018USD ($)
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
Operating Leases, Future Minimum Payments Due Through End of Current Year	$ 933
Operating Leases, Future Minimum Payments, Due in Two Years	3,579
Operating Leases, Future Minimum Payments, Due in Three Years	2,860
Operating Leases, Future Minimum Payments, Due in Four Years	2,526
Operating Leases, Future Minimum Payments, Due in Five Years	2,133
Operating Leases, Future Minimum Payments, Due Thereafter	24,595
Operating Leases, Future Minimum Payments Due	$ 36,626