Camden National (CAC) 10-K 9 Mar 18 2017 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2017	Feb. 23, 2018	Jun. 30, 2017
Document Information [Line Items]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2017
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	FY
Trading Symbol	CAC
Entity Registrant Name	CAMDEN NATIONAL CORP
Entity Central Index Key	750,686
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Entity Common Stock, Shares Outstanding		15,536,923
Entity Public Float			$ 652,073,793
Entity Well-known Seasoned Issuer	No
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No

Consolidated Statements Of Cond

Consolidated Statements Of Condition - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
ASSETS
Cash and due from banks	$ 48,107	$ 52,168
Interest-bearing deposits in other banks	54,864	35,539
Total cash and cash equivalents	102,971	87,707
Securities
Available-for-sale securities, at fair value	789,899	779,867
Held-to-maturity securities, at amortized cost (fair value of $94,913 and $94,596, respectively)	94,073	94,609
Federal Home Loan Bank and Federal Reserve Bank stock, at cost	23,670	23,203
Total investments	907,642	897,679
Loans held for sale, at fair value	8,103	14,836
Loans:	2,782,439	2,594,564
Less: allowance for loan losses	(24,171)	(23,116)
Net loans	2,758,268	2,571,448
Goodwill	94,697	94,697
Other intangible assets	4,955	6,764
Bank-owned life insurance	87,489	78,119
Premises and equipment, net	41,891	42,873
Deferred tax assets	22,776	39,263
Other assets	36,606	30,844
Total assets	4,065,398	3,864,230
Deposits
Demand	478,643	406,934
Interest checking	855,570	701,494
Savings and money market	985,508	979,263
Retail certificates of deposit	475,010	468,203
Brokered deposits	205,760	272,635
Total deposits	3,000,491	2,828,529
Short-term borrowings	541,867	530,129
Long-term borrowings	10,720	10,791
Subordinated Debt	58,911	58,755
Accrued interest and other liabilities	49,996	44,479
Total liabilities	3,661,985	3,472,683
Commitments and contingencies
Shareholders' Equity
Common stock, no par value: authorized 40,000,000 shares, issued and outstanding 15,524,704 and 15,476,379 on December 31, 2017 and 2016, respectively	156,904	156,041
Retained earnings	266,723	249,415
Accumulated other comprehensive income (loss)
Net unrealized losses on available-for-sale securities, net of tax	(10,300)	(6,085)
Net unrealized losses on cash flow hedging derivative instruments, net of tax	(5,926)	(5,694)
Net unrecognized losses on postretirement plans, net of tax	(3,988)	(2,130)
Total accumulated other comprehensive loss	(20,214)	(13,909)
Total shareholders’ equity	403,413	391,547
Total liabilities and shareholders’ equity	$ 4,065,398	$ 3,864,230

Consolidated Statements Of Con3

Consolidated Statements Of Condition (Parenthetical) - $ / shares	Dec. 31, 2017	Dec. 31, 2016
Statement of Financial Position [Abstract]
Common Stock, no par value (dollars per share)	$ 0	$ 0
Common stock, authorized	40,000,000	40,000,000
Common stock, issued	15,524,704	15,476,379
Common stock, outstanding	15,524,704	15,476,379

Consolidated Statements Of Inco

Consolidated Statements Of Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Interest Income
Interest and fees on loans	$ 114,563	$ 109,224	$ 81,221
Interest on U.S. government and sponsored enterprise obligations (taxable)	16,879	16,082	15,091
Interest on state and political subdivision obligations (nontaxable)	2,764	2,836	2,208
Interest on other investments	1,898	1,484	624
Total interest income	136,104	129,626	99,144
Interest Expense
Interest on deposits	11,811	8,633	6,511
Interest on borrowings	5,585	4,506	3,457
Interest on subordinated debentures	3,408	3,415	2,724
Total interest expense	20,804	16,554	12,692
Net interest income	115,300	113,072	86,452
Provision for credit losses	3,035	5,258	1,936
Net interest income after provision for credit losses	112,265	107,814	84,516
Non-Interest Income
Debit card income	8,079	7,578	5,277
Service charges on deposit accounts	7,529	7,210	6,423
Mortgage banking income, net	7,363	6,258	2,031
Income from fiduciary services	5,108	4,960	4,918
Bank-owned life insurance	2,370	2,594	1,680
Brokerage and insurance commissions	2,147	2,074	1,699
Other service charges and fees	2,029	1,962	1,573
Net gain on sale of securities	855	51	4
Other income	3,119	6,934	3,877
Total non-interest income	38,599	39,621	27,482
Non-Interest Expenses
Salaries and employee benefits	49,965	48,072	37,220
Furniture, equipment and data processing	9,894	9,557	8,057
Net occupancy costs	6,884	7,088	5,695
Consulting and professional fees	3,118	3,234	2,625
Other real estate owned and collection costs, net	971	3,128	2,491
Regulatory assessments	2,166	2,777	2,184
Debit card expense	2,755	2,584	1,936
Amortization of intangible assets	1,809	1,903	1,306
Merger and acquisition costs	0	866	10,415
Other expenses	10,948	10,687	9,210
Total non-interest expense	88,510	89,896	81,139
Income before income tax expense	62,354	57,539	30,859
Income Tax Expense	33,878	17,472	9,907
Net income	$ 28,476	$ 40,067	$ 20,952
Per Share Data
Basic earnings per share	$ 1.83	$ 2.59	$ 1.73
Diluted earnings per share	$ 1.82	$ 2.57	$ 1.73
Weighted average number of common shares outstanding	15,509,665	15,422,160	12,031,294
Diluted weighted average number of common shares outstanding	15,588,347	15,504,239	12,074,579

Consolidated Statements Of Comp

Consolidated Statements Of Comprehensive Income - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Statement of Comprehensive Income [Abstract]
Net income		$ 28,476	$ 40,067	$ 20,952
Net change in unrealized losses on available-for-sale securities:
Net change in unrealized losses on available-for-sale securities, net of tax of $1,017, $1,212, and $1,873, respectively		(1,888)	(2,251)	(3,479)
Net reclassification adjustment for gains included in net income, net of tax of $18, $1, and $158, respectively	[1]	(556)	(33)	(3)
Net change in unrealized losses on available-for-sale securities, net of tax		(2,444)	(2,284)	(3,482)
Net change in unrealized gains (losses) on cash flow hedging derivatives:
Net change in unrealized losses on cash flow hedging derivatives, net of tax of $134, $343, and $825, respectively		(248)	(637)	(1,533)
Net reclassification adjustment for effective portion of cash flow hedges included in interest expense, net of tax of ($709), ($593), and ($600), respectively	[2]	1,035	1,317	1,102
Net change in unrealized gains (losses) on cash flow hedging derivatives, net of tax		787	680	(431)
Postretirement plans:
Net actuarial loss, net of tax of $723, $127, and $21, respectively		(1,342)	(235)	(39)
Reclassification of amortization of net unrecognized actuarial loss and of prior service cost included in net periodic cost, net of tax of ($83), ($84), and ($51), respectively	[3]	170	152	155
Net gain (loss) on postretirement plans, net of tax		(1,172)	(83)	116
Other comprehensive loss		(2,829)	(1,687)	(3,797)
Comprehensive income		$ 25,647	$ 38,380	$ 17,155
[1]	(1) Reclassified into the consolidated statements of income within net gain on sale of securities.
[2]	(2)Reclassified into the consolidated statements of income within interest on borrowings and subordinated debentures.
[3]	(3) Reclassified into the consolidated statements of income within salaries and employee benefits.

Consolidated Statements Of Com6

Consolidated Statements Of Comprehensive Income (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Statement of Comprehensive Income [Abstract]
Net change in unrealized gain (loss) on available-for-sale securities, tax effect	$ 1,017	$ 1,212	$ 1,873
Net reclassification adjustment for gains included in net income, tax effect	299	18	1
Net change in unrealized gains (losses) on cash flow hedging derivatives, tax effect	134	343	825
Net reclassification adjustments for effective portion of cash flow hedges included in interest expense, tax effect	(557)	(709)	(593)
Net actuarial (loss) gain, tax effect	723	127	21
Reclassification of amortization of net unrecognized actuarial loss and of prior service cost included in net periodic cost, tax effect	$ (92)	$ (83)	$ (84)

Consolidated Statements Of Chan

Consolidated Statements Of Changes In Shareholders' Equity - USD ($)		Total	Common Stock		Retained Earnings	Accumulated Other Comprehensive Income (Loss)
Beginning Balance (in shares) at Dec. 31, 2014			11,139,333
Beginning Balance at Dec. 31, 2014		$ 245,109,000	$ 41,555,000		$ 211,979,000	$ (8,425,000)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income		20,952,000			20,952,000
Other comprehensive loss, net of tax		(3,797,000)				(3,797,000)
Stock-based compensation expense		836,000	$ 836,000
Exercise of stock options and issuance of restricted stock, net of repurchase for tax withholdings and tax benefit (in shares)			66,741
Exercise of stock options and issuance of vested share awards, net of repurchase for tax withholdings		753,000	$ 753,000
Common stock repurchased (in shares)			0
Equity issuance costs incurred for the SBM Financial, Inc. acquisition		(612,000)	$ (612,000)
Cash dividends declared ( $0.74, $0.80 and $0.83 per share in 2016, 2015, and 2014, respectively)	[1]	(10,602,000)			(10,602,000)
Equity issuance costs		(612,000)
SBM acquisition common stock issuance (in shares)			4,124,643
SBM acquisition common stock issuance		108,561,000	$ 108,561,000
SBM acquisition non-qualified stock option awards		1,990,000	$ 1,990,000
Ending Balance (in shares) at Dec. 31, 2015			15,330,717
Ending Balance at Dec. 31, 2015		363,190,000	$ 153,083,000		222,329,000	(12,222,000)
New Accounting Pronouncement or Change in Accounting Principle, Effect of Change on Net Income			$ 72,000	[1]	(72,000)
Stock Issued During Period, Shares, Stock Splits			(173)
Stockholders' Equity Note, Stock Split, Reduction of Capital		(5,000)	$ (5,000)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income		40,067,000			40,067,000
Other comprehensive loss, net of tax		(1,687,000)				(1,687,000)
Stock-based compensation expense		1,997,000	$ 1,997,000
Exercise of stock options and issuance of restricted stock, net of repurchase for tax withholdings and tax benefit (in shares)			145,835
Exercise of stock options and issuance of vested share awards, net of repurchase for tax withholdings		894,000	$ 894,000
Cash dividends declared ( $0.74, $0.80 and $0.83 per share in 2016, 2015, and 2014, respectively)	[1]	(12,909,000)			(12,909,000)
Equity issuance costs		0
Ending Balance (in shares) at Dec. 31, 2016			15,476,379
Ending Balance at Dec. 31, 2016		391,547,000	$ 156,041,000		249,415,000	(13,909,000)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income		28,476,000			28,476,000
Reclassification from AOCI, Current Period, Tax	[2]				3,476,000	(3,476,000)
Other comprehensive loss, net of tax		(2,829,000)				(2,829,000)
Stock-based compensation expense		1,469,000	$ 1,469,000
Exercise of stock options and issuance of restricted stock, net of repurchase for tax withholdings and tax benefit (in shares)			48,325
Exercise of stock options and issuance of vested share awards, net of repurchase for tax withholdings		(606,000)	$ (606,000)
Cash dividends declared ( $0.74, $0.80 and $0.83 per share in 2016, 2015, and 2014, respectively)	[1]	(14,644,000)			(14,644,000)
Equity issuance costs		0
Ending Balance (in shares) at Dec. 31, 2017			15,524,704
Ending Balance at Dec. 31, 2017		$ 403,413,000	$ 156,904,000		$ 266,723,000	$ (20,214,000)
[1]	In the second quarter of 2016, the Company adopted ASU 2016-09, effective January 1, 2016. The Company made a policy election to not estimate the forfeiture rate in the accounting for share-based compensation on its unvested share-based awards. The change in policy was accounted for on a modified-retrospective basis and represents the cumulative effect adjustment to shareholders' equity.
[2]	In December of 2017, the Company early adopted ASU 2018-02, as a result, the Company made a policy election to release income tax effects, as a result of the Tax Act, from AOCI to retained earnings.

Consolidated Statements Of Cha8

Consolidated Statements Of Changes In Shareholders' Equity (Parenthetical) - $ / shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Statement of Stockholders' Equity [Abstract]
Cash dividends declared, per share	$ 0.94	$ 0.83	$ 0.80

Consolidated Statements Of Cash

Consolidated Statements Of Cash Flows	12 Months Ended
	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)
Operating Activities
Net income	$ 28,476,000	$ 40,067,000	$ 20,952,000
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for credit losses	3,035,000	5,258,000	1,936,000
Depreciation and amortization expense	3,761,000	4,426,000	3,614,000
Purchase accounting accretion, net	(2,834,000)	(5,048,000)	(367,000)
Investment securities amortization and accretion, net	3,122,000	3,135,000	2,244,000
Stock-based compensation expense	1,469,000	1,997,000	836,000
Amortization of intangible assets	1,809,000	1,903,000	1,306,000
Net gains on sale of investment securities	(855,000)	(51,000)	(4,000)
Net increase in other real estate owned valuation allowance and (gain) loss on disposition	(15,000)	35,000	362,000
Originations of mortgage loans held for sale	(211,568,000)	(236,450,000)	(72,032,000)
Proceeds from the sale of mortgage loans	224,883,000	238,351,000	62,485,000
Gain on sale of mortgage loans, net of origination costs	(6,256,000)	(6,201,000)	(1,278,000)
Cost of fixed assets disposals associated with the SBM Financial, Inc. acquisition	0	0	1,130,000
Proceeds from bank-owned life insurance death benefits	0	(507,000)	0
Proceeds from bank-owned life insurance death benefits	0	1,092,000	0
(Increase) decrease in other assets	12,060,000	11,836,000	(7,062,000)
Increase (decrease) in other liabilities	1,247,000	(1,333,000)	1,796,000
Net cash provided by operating activities	58,334,000	58,510,000	15,918,000
Investing Activities
Cash received in the SBM Financial, Inc. acquisition, net of cash paid	0	0	59,917,000
Proceeds from sales and maturities of available-for-sale securities	154,973,000	184,564,000	156,434,000
Purchase of available-for-sale securities	(170,495,000)	(220,169,000)	(111,170,000)
Purchase of securities held-to-maturity	0	(10,986,000)	(64,355,000)
Net increase in loans	(187,740,000)	(103,699,000)	(94,811,000)
Proceeds from sale of premises and equipment	137,000	90,000	0
Purchase of premises and equipment	(2,844,000)	(1,671,000)	(3,189,000)
Purchase of Federal Home Loan Bank and Federal Reserve Bank stock	(12,290,000)	(7,342,000)	(1,594,000)
Proceeds from sale of other real estate owned	11,823,000	5,652,000	471,000
Proceeds from sale of other real estate owned	808,000	730,000	2,825,000
Recoveries of previously charged-off loans	497,000	486,000	728,000
Purchase of bank-owned life insurance	(7,000,000)	(16,700,000)	0
Net cash used in investing activities	(212,131,000)	(169,045,000)	(54,744,000)
Financing Activities
Net increase in deposits	172,291,000	103,027,000	71,825,000
Net proceeds from (repayments of) borrowings less than 90 days	36,699,000	77,227,000	(18,105,000)
Repayments on Federal Home Loan Bank long-term advances	(20,000,000)	(25,000,000)	(11,039,000)
Proceeds from Federal Home Loan Bank long-term advances	0	0	10,000,000
Repayments of Other Debt	(5,000,000)	(25,000,000)	0
Issuance of subordinated debt, net of costs	0	0	14,464,000
Equity issuance costs	0	0	(612,000)
Exercise of stock options and issuance of restricted stock, net of repurchase for tax withholdings	606,000	(894,000)	(753,000)
Cash dividends paid on common stock and cash in lieu for fractional shares paid due to stock split	(14,323,000)	(12,394,000)	(9,785,000)
Net cash provided by financing activities	169,061,000	118,754,000	57,501,000
Net increase in cash and cash equivalents	15,264,000	8,219,000	18,675,000
Cash and cash equivalents at beginning of year	87,707,000	79,488,000	60,813,000
Cash and cash equivalents at end of year	102,971,000	87,707,000	79,488,000
Supplemental information
Interest paid	20,774,000	16,661,000	12,588,000
Income taxes paid	16,841,000	10,647,000	12,205,000
Transfer of loans and premises to other real estate owned	0	383,000	2,175,000
Measurement-period adjustments	0	960,000	0
Assets acquired in the acquisition of SBM Financial, Inc., excluding net cash received (not adjusted for measurement-period adjustments)	0	0	729,283,000
Liabilities assumed in the acquisition of SBM Financial Inc. (not adjusted for measurement-period adjustments)	0	0	729,500,000
Common stock and stock options issued in connection with the SBM Financial, Inc. acquisition	$ 0	$ 0	$ 110,551,000

Business and Summary of Signifi

Business and Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2017
Accounting Policies [Abstract]
Business and Summary of Significant Accounting Policies	Business and Summary of Significant Accounting Policies Acronyms and Abbreviations. The acronyms and abbreviations identified below are used in the notes to the consolidated financial statements. The following is provided to aid the reader and provide a reference page when reviewing these notes to the consolidated financial statements. AFS: Available-for-sale HPFC: Healthcare Professional Funding Corporation, a wholly-owned subsidiary of Camden National Bank ALCO: Asset/Liability Committee HTM: Held-to-maturity ALL: Allowance for loan losses IRS: Internal Revenue Service AOCI: Accumulated other comprehensive income (loss) LIBOR: London Interbank Offered Rate ASC: Accounting Standards Codification LTIP: Long-Term Performance Share Plan ASU: Accounting Standards Update Management ALCO: Management Asset/Liability Committee Bank: Camden National Bank, a wholly-owned subsidiary of Camden National Corporation MBS: Mortgage-backed security BOLI: Bank-owned life insurance MSPP: Management Stock Purchase Plan Board ALCO: Board of Directors' Asset/Liability Committee N.M.: Not meaningful CCTA: Camden Capital Trust A, an unconsolidated entity formed by Camden National Corporation OCC: Office of the Comptroller of the Currency CDs: Certificate of deposits OCI: Other comprehensive income (loss) Company: Camden National Corporation OREO: Other real estate owned CMO: Collateralized mortgage obligation OTTI: Other-than-temporary impairment DCRP: Defined Contribution Retirement Plan SBM: SBM Financial, Inc., the parent company of The Bank of Maine EPS: Earnings per share SERP: Supplemental executive retirement plans FASB: Financial Accounting Standards Board Tax Act: Tax Cuts and Jobs Act of 2017, enacted on December 22, 2017 FDIC: Federal Deposit Insurance Corporation TDR: Troubled-debt restructured loan FHLB: Federal Home Loan Bank UBCT: Union Bankshares Capital Trust I, an unconsolidated entity formed by Union Bankshares Company that was subsequently acquired by Camden National Corporation FHLBB: Federal Home Loan Bank of Boston U.S.: United States of America FRB: Federal Reserve System Board of Governors 2003 Plan: 2003 Stock Option and Incentive Plan FRBB: Federal Reserve Bank of Boston 2012 Plan: 2012 Equity and Incentive Plan GAAP: Generally accepted accounting principles in the United States General Business. Camden National Corporation, a Maine corporation (the "Company"), is the bank holding company for Camden National Bank (the "Bank") and is headquartered in Camden, Maine. The primary business of the Company is to attract deposits from, and to extend loans to, consumer, institutional, municipal, non-profit and commercial customers. The Company, through the Bank, offers commercial and consumer banking products and services, and through Camden Financial Consultants, a division of the Bank, and Camden National Wealth Management, a department of the Bank, offers brokerage and insurance services as well as investment management and fiduciary services. The Bank's deposits are insured by the FDIC, subject to regulatory limits. Principles of Consolidation . The accompanying consolidated financial statements include the accounts of the Company and the Bank (which includes the consolidated accounts of HPFC, Property A, Inc. and Property P, Inc.). All intercompany accounts and transactions have been eliminated in consolidation. Assets held by the Bank in a fiduciary capacity, through Camden National Wealth Management, are not assets of the Company and, therefore, are not included in the consolidated statements of condition. The Company also owns 100% of the common stock of CCTA and UBCT. These entities are unconsolidated subsidiaries of the Company. Reclassifications . Certain reclassifications have been made to prior year amounts to conform to the current year's presentation. Use of Estimates . The preparation of the financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting periods. Actual results could vary from these estimates. Several estimates are particularly critical and are susceptible to significant near-term change, including the ALL, the accounting for business combinations including subsequent impairment analyses for goodwill and other intangible assets, accounting for income taxes, postretirement benefits and asset impairment judgments, including OTTI of investment securities. Subsequent Events . The Company has evaluated events and transactions subsequent to December 31, 2017 for potential recognition or disclosure as required by GAAP. Significant Concentration of Credit Risk. The Bank grants loans primarily to customers in Maine. Although the Bank has a diversified loan portfolio, a large portion of the Bank's loans are secured by commercial or residential real estate located in Maine and is subject to volatility within Maine's real estate market. Furthermore, the debtors' ability to honor their contracts is highly dependent upon other economic factors throughout Maine. The Bank does not generally engage in non-recourse lending and typically will require the principals of any commercial borrower to obligate themselves personally on the loan. Cash and Cash Equivalents . For the purposes of reporting cash flows, cash and cash equivalents consist of cash on hand and amounts due from banks. The Bank is required by the FRB to maintain cash reserves equal to a percentage of deposits. The Company maintains the reserve balances in cash on hand or at the FRB. Investment Securities. Investment securities are classified at the time of purchase as AFS, HTM, or trading. The classification of investment securities are constantly re-evaluated for consistency with corporate goals and objectives. Trading securities are carried at fair value on the consolidated statements of condition with subsequent changes to fair value recorded in earnings. At December 31, 2017 and 2016, the Company did no t have any investment securities classified as trading securities on its consolidated statements of condition. Debt securities for which the Company has the positive intent and ability to hold to maturity are classified as HTM and recorded at amortized cost on the consolidated statements of condition. At December 31, 2017 and 2016, the Company had investment securities of $94.1 million and $94.6 million , respectively, classified as HTM and carried at amortized cost on its consolidated statements of condition. Investment securities that are not classified as HTM or trading securities are classified as AFS and are carried at fair value on the Company's consolidated statements of condition with subsequent changes to fair value recorded within AOCI, net of tax. At December 31, 2017 and 2016, the Company had investment securities of $789.9 million and $779.9 million , respectively, classified as AFS and carried at fair value on its consolidated statements of condition. Purchase premiums and discounts are recognized in interest income on the consolidated statements of income using the interest method over the period to maturity (or issuer call option date, if earlier) and are recorded on the trade date. Upon sale of an investment security designated as AFS, the unrealized gain or loss recorded within AOCI, net of tax, is reversed. Gains and losses on the sale of investment securities are recognized within non-interest income on the consolidated statements of income and are recorded on the trade date using the specific identification method. Management conducts a quarterly review and evaluation of its debt and equity securities portfolio to determine if the decline in fair value of any security appears to be other-than-temporary. The factors considered by management in its review include, but are not limited to: the length of time and the extent to which the fair value has been less than cost, the financial condition and near-term prospects of the issuer, the credit ratings of the security or issuer, whether the decline in fair value appears to be issuer specific or, alternatively, a reflection of general market or industry conditions, and the Company’s intent and ability to hold the security for a period of time sufficient to allow for a recovery in fair value. Should the Company determine that the decline in the fair value of an equity security was other-than-temporary, the Company recognizes the impairment on the equity security within non-interest income on the consolidated statements of income when identified. For debt securities where the Company does not intend to sell the security and it is not more-likely-than-not that the Company will be required to sell the security before recovery of its amortized cost basis, the other-than-temporary decline in the fair value of the debt security related to: (i) credit loss is recognized in non-interest income on the consolidated statements of income; and (ii) other factors is recognized in AOCI, net of tax. For debt securities where the Company intends to sell the security or more-likely-than-not will be required to sell the security before recovery of its amortized cost, the Company recognizes the OTTI equal to the entire difference between the security’s cost basis and its fair value within non-interest income on the consolidated statements of income. The Bank is a member of the FHLBB and FRBB, and as a member, the Bank is required to hold a certain amount of FHLBB and FRB common stock. This stock is a non-marketable equity security and is reported at cost. The Company evaluates its FHLBB and FRB common stock for impairment based on the ultimate recoverability of the par value rather than by recognizing temporary declines in value. Loans Held for Sale. The Company has elected the fair value option for loans classified as held for sale on the consolidated statements of condition. Designation of loans as held for sale is determined based on the Company's intent and is, typically, completed as the loans are underwritten. The fair value for loans held for sale is determined using quoted secondary market prices or executed sales agreements. Management constantly evaluates its loan portfolio, in conjunction with asset/liability management practices, and will opt to sell certain loans, typically new 30 -year residential mortgages, to manage the Company's interest rate exposure and for other business purposes, including generating fee income through mortgage sale gains. At December 31, 2017 and 2016, the fair value of loans designated as held for sale on its consolidated statements of condition were $8.1 million and $14.8 million , respectively. Originated Loans and Acquired Loans . Loans are reported at amortized cost, or fair value in the case of acquired loans, adjusted for any partial charge-offs and net of any deferred loan fees or costs. For originated loans, interest income is accrued based upon the daily principal amount outstanding except for loans on non-accrual status. For acquired loans, interest income is also accrued based upon the daily principal amount outstanding and is then further adjusted by the accretion of any discount or amortization of any premium associated with the loan. For originated loans, loan fees and certain direct origination costs are deferred and amortized into interest income over the contractual term of the loan using the level-yield method. When a loan is paid off, the unamortized portion is recognized in interest income. A loan is classified as non-accrual generally when it becomes 90 days past due as to interest or principal payments, or sooner if management considers such action to be prudent. All previously accrued but unpaid interest on non-accrual loans is reversed from interest income in the period in which the loan is considered delinquent and the amortization of any unamortized net deferred origination loan fees/costs stops. Interest payments received on non-accrual loans, including impaired loans, are applied as a reduction of principal. A loan remains on non-accrual status until all principal and interest amounts contractually due are brought current and future payments are reasonably assured. Should a loan transition from non-accrual status back to accrual status, the unrecognized interest earned during the period the loan was on non-accrual status and unamortized deferred origination fees and costs are recognized over the remaining contractual life of the loan using the level-yield method. ALL. The ALL is established through provisions for loan losses charged to income. Losses on loans, including impaired loans, are charged to the ALL when all or a portion of a loan is deemed to be uncollectible. Recoveries of loans previously charged off are credited to the ALL when realized. In determining the appropriate level of ALL, the Company uses a methodology to systematically measure the amount of estimated loan loss exposure inherent in the loan portfolio. The methodology includes three elements: (1) identification of loss allocations for certain specific loans, (2) loss allocation factors for certain loan types based on credit risk and loss experience, and (3) general loss allocations for other qualitative and environmental factors. The allocations for specific loans is determined based on loans that have a principal balance of $500,000 or more that are classified as substandard or doubtful and are on non-accrual status. Effective January 1, 2017, the Company's internal policy for assessing specific loans for impairment was increased from $250,000 to $500,000. The qualitative factors for assessing a loan individually for impairment in accordance with the Company's internal policy were unchanged, and continue to require the loan to be classified as substandard or doubtful and on non-accrual status. For such loans that are also classified as impaired, an allowance is established when the discounted expected future cash flows (or collateral value or observable market price) of the impaired loan is lower than the recorded investment of that loan. Loans that do not meet the above criteria are separated into risk pools by portfolio segment and risk ratings. The Company then evaluates each risk pool collectively for impairment through loss allocation factors. The Company uses a risk rating system for certain loan segments to determine the credit quality of these loan pools and applies the related loss allocation factors. In assessing the risk rating of a particular loan, the Company considers, among other factors, the obligor’s debt capacity, financial condition, the level of the obligor’s earnings, the amount and sources of repayment, the performance with respect to loan terms, the adequacy of collateral, the level and nature of contingent liabilities, management strength, and the industry in which the obligor operates. These factors are based on an evaluation of historical information, as well as subjective assessment and interpretation of current conditions. Emphasizing one factor over another, or considering additional factors that may be relevant in determining the risk rating of a particular loan but which are not currently an explicit part of the Company's methodology, could impact the risk rating assigned to that loan. The Company at least annually, and more frequently as deemed prudent by management, reassesses and revises the loss allocation factors used in the assignment of loss exposure to appropriately reflect the analysis of loss experience. Portfolios of more homogeneous populations of loans including home equity and consumer loans are analyzed as groups taking into account delinquency rates and other economic conditions which may affect the ability of borrowers to meet debt service requirements, including interest rates and energy costs. The Company also considers regulatory guidance, historical loss ranges, portfolio composition, and other changes in the portfolio. An additional allocation is determined based on a judgmental process whereby management considers qualitative and quantitative assessments of other environmental factors. Since the methodology is based upon historical experience and trends, as well as management’s judgment, factors may arise that result in different estimations. Significant factors that could give rise to changes in these estimates may include, but are not limited to, changes in economic conditions in the Company’s market areas, concentration of risk, declines in local property values, and regulatory guidance. Loans past due 30 days or more are considered delinquent. In general, secured loans that are delinquent for 90 consecutive days are placed on non-accrual status, and are subject to impairment and/or loss assessment in accordance with established internal policy. In general, unsecured loans that are delinquent for 90 consecutive days are charged off. In cases where a borrower experiences financial difficulties and the Company makes certain concessionary modifications to contractual terms, the loan is classified as a TDR. Modifications may include adjustments to interest rates, extensions of maturity, and other actions intended to minimize economic loss and avoid foreclosure or repossession of collateral. An allowance is established on a loan classified as a TDR if the present value of expected future cash flows (or, alternatively, the observable market price of the loan or the fair value of the collateral if the loan is collateral-dependent) is less than the recorded investment of the loan. Non-accrual loans that are restructured as TDRs remain on non-accrual status for a period of at least six months to demonstrate that the borrower can meet the restructured terms. If the restructured loan is on accrual status prior to being modified, it is reviewed to determine if the modified loan should remain on accrual status. If the borrower’s ability to meet the revised payment schedule is not reasonably assured, the loan is classified as a non-accrual loan. Loans classified as TDRs remain classified as such for the life of the loan, except in limited circumstances, when it is determined that the borrower is performing under the modified terms and the restructuring agreement specified an interest rate greater than or equal to an acceptable market rate for a comparable new loan at the time of the restructuring. Goodwill and Core Deposit Intangible Assets . Goodwill represents the excess cost of an acquisition over the fair value of the net assets acquired. Goodwill is not subject to amortization but rather is evaluated at least annually for impairment, or as events and circumstances dictate, at the reporting unit level. The Company's two reporting unit levels are (i) banking and (ii) financial services. The banking reporting unit is representative of the Company's core banking business line, while the financial services reporting unit is representative of the Company's wealth management and trust services business line. Any impairment is charged to non-interest expense on the consolidated statements of income. Goodwill is evaluated for impairment annually as of November 30 th , or more frequently should external and/or internal factors warrant such. The Company may utilize a qualitative analysis (commonly referred to as "step zero") and/or a quantitative analysis to evaluate its reporting units' goodwill for impairment. The Company may utilize the qualitative analysis for an individual reporting unit or for both reporting units any given year. Furthermore, the Company has the option to by-pass the qualitative analysis for any given year and perform the quantitative analysis. Using a qualitative analysis to assess a reporting unit's goodwill for impairment, the Company will consider various factors to determine if it is more-likely-than-not that a reporting unit's carrying value exceeds its fair value. These factors include, but are not limited to, the overall macro-economic environment; industry economic and regulatory environment; and company specific factors, including, but not limited to, performance, Company common stock share price, competition and/or significant changes in senior management. Should the Company determine it is more-likely-than-not that the carrying value of a reporting unit exceeds its fair value, then the Company would perform then perform the next step of the goodwill impairment test, which is a quantitative analysis. If the Company were to determine it is not more-likely-than-not that the carrying value of a reporting unit exceeds its fair value, the Company would have completed its goodwill impairment evaluation and concluded the reporting unit's goodwill was not impaired. After performing the qualitative analysis and determining it's more-likely-than-not that the carrying value of a reporting unit exceeds its fair value or if the Company by-passed the qualitative analysis, it would perform a quantitative analysis to determine if the carrying value of a reporting unit exceeds its fair value. The Company may use various valuation techniques such as a discounted cash flow model, a comparative market transaction multiple approach and/or other valuation methods, to determine the reporting unit's fair value. If the fair value of the reporting unit is greater than its carrying value, then the reporting unit is not deemed to be impaired and no further assessment is required. However, if the fair value of the reporting unit is less than its carrying value, the Company would then be required to fair value the tangible and identifiable intangible assets, and liabilities of the reporting unit, to derive an implied fair value of goodwill for the reporting unit. If the implied fair value of goodwill for the reporting unit is greater than its carrying value, then the reporting unit’s goodwill is not impaired. However, if the reporting unit’s implied fair value of goodwill is less than its carrying value, an impairment charge is then recorded to carry goodwill at its calculated implied fair value. The Company completed its annual goodwill impairment testing as of November 30, 2017 , 2016 and 2015 for each reporting unit and goodwill was not impaired. Core deposit intangible assets represents the estimated value of acquired customer relationships and is amortized on a straight-line basis over the estimated life of those relationships ( 5 to 10 years from the acquisition dates). Core deposit intangibles are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount may not be recoverable. If necessary, management will test the core deposit intangibles for impairment by comparing its carrying value to the expected undiscounted cash flows of the assets. If the undiscounted cash flows of the intangible assets exceed its carrying value then the intangible assets are deemed to be fully recoverable and not impaired. However, if the undiscounted cash flows of the intangible assets are less than its carrying value then management must compare the fair value of the intangible assets to its carrying value. If the fair value of the intangible assets exceeds its carrying value then the intangible assets are not impaired. If the fair value of the intangible assets is less than its carrying value then an impairment charge is recorded to mark the carrying value of the intangible assets to fair value. For the year ended December 31, 2017 , 2016 or 2015 , there were no events or changes in circumstances that indicated the carrying amount may not be recoverable. BOLI . BOLI represents the cash surrender value of life insurance policies on the lives of certain active and retired employees where the Company is the beneficiary and is recorded as an asset on the Company's consolidated statements of condition. Increases in the cash surrender values of the policies, as well as death benefits received, net of any cash surrender value, are recorded in non-interest income on the consolidated statements of income, and are not subject to income taxes. The Company reviews the financial strength of the insurance carriers prior to the purchase of life insurance policies and no less than annually thereafter. A life insurance policy with any individual carrier is limited to 15% of Tier I capital (as defined for regulatory purposes) and the total cash surrender value of life insurance policies is limited to 25% of Tier I capital. Premises and Equipment . Premises and equipment are stated at cost less accumulated depreciation. Acquired premises and equipment (through the acquisition of a company or branch acquisition) are stated at their estimated fair values as of the acquisition date less accumulated depreciation that occurred subsequent to the acquisition date. Depreciation and amortization are computed using the straight-line method over the estimated useful lives of the related assets. Leasehold improvements are amortized over the lesser of the term of the respective lease or the estimated life of the improvement. Land is carried at cost. Software costs are stated at cost less accumulated depreciation within other assets on the consolidated statements of condition. Amortization expense is calculated using the straight-line method over the estimated useful lives of the related assets. OREO . OREO properties acquired through foreclosure or deed-in-lieu of foreclosure are recorded initially at estimated fair value less estimated costs to sell. Any write-down of the recorded investment in the related loan is charged to the ALL upon transfer to OREO. Upon acquisition of a property, a current appraisal is used or an internal valuation is prepared to substantiate fair value of the property. Any subsequent declines in the fair value of a property are recorded as a valuation allowance on the asset. Any subsequent increases in the fair value of a property are recorded as reductions of the valuation allowance, but not below zero. Upon a sale of an OREO property, any excess of the carrying value over the sale proceeds is recognized as a loss on sale. Any excess of sale proceeds over the carrying value of the OREO property is first applied as a recovery to the valuation allowance, if any, with the remainder being recognized as a gain on sale. Operating expenses, including legal and other direct expenses, and changes in the valuation allowance relating to foreclosed assets are included in other non-interest expense on the consolidated statements of income. Mortgage Banking . Residential real estate mortgages are originated by the Company both for its portfolio and for sale into the secondary market. The transfer of these financial assets is accounted for as a sale when control over the asset has been surrendered. Control is deemed to be surrendered when (i) the asset has been isolated from the Company, (ii) the transferee obtains the right (free of conditions that constrain it from taking advantage of that right) to pledge or exchange the transferred asset, and (iii) the Company does not maintain effective control over the transferred asset through an agreement to repurchase them before their maturity. The Company records the gain on sale of the financial asset within mortgage banking income, net on its consolidated statements of income, net of direct and indirect costs incurred to originate the loan. Servicing assets are recognized as separate assets when servicing rights are acquired through the sale of residential mortgage loans with servicing rights retained. Capitalized servicing rights, which are reported in other assets on the consolidated statements of condition, are initially recorded at fair value and are amortized in proportion to, and over the period of, the estimated future servicing of the underlying mortgages (typically, the contractual life of the mortgage). The amortization of mortgage servicing rights is recorded as a reduction of loan servicing fee income within non-interest income on the consolidated statements of income. Servicing assets are evaluated for impairment quarterly based upon the fair value of the rights as compared to amortized cost. Impairment is determined by stratifying rights by predominant characteristics, such as interest rates and terms. Fair value is determined using prices for similar assets with similar characteristics, when available, or based upon discounted cash flows using market-based assumptions. Impairment of the servicing assets is recognized through a valuation allowance to the extent that fair value is less than the capitalized amount. If it is later determined that all or a portion of the impairment no longer exists, a reduction of the allowance may be recorded increasing income, but not below zero. Servicing fee income is recorded for fees earned for servicing loans for investors. The fees are based on a contractual percentage of the outstanding principal or a fixed amount per loan and are recorded as income within non-interest income on the consolidated statements of income when earned. Short-Term and Long-Term Borrowings. Short-term borrowings consist of borrowings maturing within one year of the consolidated statement of condition date, while long-term borrowings consist of borrowings maturing in one or more years. The Company's borrowings include retail and wholesale repurchase agreements, FHLBB overnight and short-term borrowings, federal funds purchased, a capital lease, and line of credit advances. The Company is required to post collateral for certain borrowings, for which it, generally, posts loans and/or investment securities as collateral. Income Taxes . Income taxes are accounted for using the asset and liability method. Under this method, deferred tax assets and liabilities are recognized for the future tax implications attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases. If current information suggests that it is not more likely than not that the Company will be able to realize the deferred tax assets, a valuation allowance is established. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income in the period that includes the enactment date. The Company assesses quarterly whether or not a valuation allowance on its deferred tax assets is necessary. If it is more likely than not that the Company will not be able to realize the benefit of the deferred tax assets then a valuation allowance is established on the deferred tax asset not expected to be realized. At December 31, 2017 and 2016, the Company did not carry a valuation allowance on its deferred tax assets. Effective January 1, 2016, the Company accounted for its windfall tax benefits and shortfalls, which are generated upon exercise of a non-qualified stock option or a disqualifying incentive stock option, within income tax expense on the consolidated statements of income as a discrete period item in the quarter generated. EPS . Basic EPS excludes dilution and is computed by dividing net income applicable to common stock by the weighted-average number of common shares outstanding for the period. Diluted EPS reflects the potential dilution that could occur if certain securities or other contracts to issue common stock (such as stock options) were exercised or converted into additional common shares that would then share in the earnings of the Company. Diluted EPS is computed by dividing net income applicable to common stock by the weighted-average number of common shares outstanding for the period, plus an incremental number of common-equivalent shares computed using the treasury stock method. Unvested share-based payment awards which include the right to receive non-forfeitable dividends are considered to participate with common stock in undistributed earnings for purposes of computing EPS. Restricted share grants and management stock purchase grants are considered participating securities for this purpose. Accordingly, the Company is required to calculate basic and diluted EPS using the two-class method. The calculation of EPS using the two-class method (i) excludes any dividends paid or owed on participating securities and any undistributed earnings considered to be attributable to participating securities from the numerator and (ii) excludes the dilutive impact of the participating securities from the denominator. Effective Septemb

Mergers and Acquisitions

Mergers and Acquisitions	12 Months Ended
	Dec. 31, 2017
Business Combinations [Abstract]
Mergers and Acquisitions	Mergers and Acquisitions Acadia Trust, N.A. — November 30, 2016 On November 30, 2016, the Company completed its merger of Acadia Trust, N.A., the Company's wholly-owned subsidiary, into the Bank, also the Company's wholly-owned subsidiary, and created a new wealth management and trust department of the Bank, Camden National Wealth Management. The merger did not qualify as a business combination and did not have any effect on the Company's consolidated financial condition. Acquisition of SBM Financial, Inc. — October 16, 2015 On October 16, 2015, the Company completed its acquisition of 100% of SBM's common stock, through the completion of a two-step merger of Camden National Corporation, SBM and Atlantic Acquisitions, LLC, a wholly-owned subsidiary of Camden National Corporation (the "Merger"). The Merger qualified as a tax-free reorganization for federal income tax purposes and, pursuant to the terms and merger agreement, dated as of March 29, 2015, by and among Camden National Corporation, SBM and Atlantic Acquisitions, LLC ("Merger Agreement"), each share of SBM's common stock outstanding at the effective time of the acquisition was converted into the right to receive, at the election of the stockholder and subject to the allocation and proration procedures described in the Merger Agreement, either: (1) $206.00 in cash, without interest or (2) 8.132 shares of common stock of the Company; provided that 80% of the SBM shares outstanding immediately prior to the effective time of the acquisition were converted into the right to receive common stock of the Company and the remaining SBM shares were converted into the right to receive cash. The total consideration paid by the Company was $136.7 million , consisting of (i) $26.1 million in cash; (ii) 4,124,643 shares of Camden common stock valued at $108.6 million , based on the October 16, 2015 closing price of the Company's common stock of $26.32 per share; and (iii) the fair value of 139,032 non-qualified stock options issued under the 2012 Plan of $2.0 million . Pursuant to the Merger Agreement, all unexercised non-qualified stock options held by SBM option holders immediately vested upon completion of the acquisition and were to roll into the Company's non-qualified stock options using the 8.132 share conversion ratio (rounded down to the nearest whole share). The non-qualified stock options issued under the Company's 2012 Plan maintained the same terms and conditions as previously held under SBM's equity plan. The fair value of the non-qualified stock options approximated the intrinsic value of the non-qualified stock options at acquisition date. The Merger complemented the Company's existing footprint within Maine, while expanding its presence in the higher growth Southern Maine market and into Massachusetts. In addition to providing incremental market share and increasing its presence within Southern Maine, the acquisition improved the Company's interest rate risk exposure in a rising rate environment through a larger mix of variable rate loans as percentage of total loans and additional core deposits (non-interest checking, interest checking, savings and money market accounts). The Company accounted for the Merger using the acquisition method. The acquisition method requires the acquirer to recognize the assets acquired and the liabilities assumed at their fair values as of the acquisition date (with limited exceptions), and does not provide for acquisition expenses to be capitalized as part of the transaction. The Company incurred acquisition-related costs for the periods indicated as detailed below: For The Year Ended December 31, 2017 2016 2015 Salaries and employee benefits (1) $ — $ 8 $ 3,240 Furniture, equipment and data processing — 279 1,531 Net occupancy — 439 1,237 Consulting and professional fees (2) — 80 2,453 Other expenses (3) — 60 1,954 Total merger and acquisition costs $ — $ 866 $ 10,415 (1) Includes the costs associated with pre-existing change-in-control agreements in place at the time of the Merger and employee termination costs, including severance. (2) Includes the cost of a negotiated non-compete arrangement entered into in connection with the Merger of $400,000 in 2015. (3) Other expenses include marketing and insurance costs, certain contract termination costs, various printing and mailing costs associated with various customer communications, and travel-related costs associated with the integration of the two companies in 2015. Also in connection with the Merger, the Company incurred certain equity issuance costs totaling $612,000 related to the registration of additional shares of the Company's common stock. These costs have been accounted for as a reduction to shareholders' equity and have been presented as such within the Company's consolidated statements of changes in shareholders' equity for the year ended December 31, 2015. The following table summarizes the estimated fair value of the assets acquired and liabilities assumed as of the date of the acquisition: As Acquired Fair Value Adjustments (Previously Reported) Measurement-Period Adjustments As Recorded at Acquisition Consideration Paid: Cash $ 26,125 Company common stock (4,124,643 shares at $26.32 per share) 108,561 Non-qualified stock options 1,990 Total consideration paid 136,676 Recognized identifiable assets acquired and liabilities assumed, at fair value: Loans and loans held for sale $ 639,390 $ (11,497 ) $ 137 628,030 Cash and due from banks 86,042 — — 86,042 Investments 39,716 26 — 39,742 Deferred tax assets 26,293 (1,177 ) 666 25,782 Premises and equipment 16,851 7,093 — 23,944 OREO 2,530 (1,801 ) — 729 Core deposit intangible assets — 6,608 — 6,608 Other assets 5,421 (170 ) 157 5,408 Deposits and borrowings 719,640 1,546 — 721,186 Other liabilities 8,512 (198 ) — 8,314 Total identified assets acquired and liabilities assumed, at fair value $ 88,091 $ (2,266 ) $ 960 86,785 Goodwill $ 49,891 The Company completed its purchase accounting for the Merger by June 30, 2016. In connection with completion of its accounting for the acquisition, the Company made certain measurement-period adjustments that decreased goodwill reported at December 31, 2015 by $960,000 . The measurement-period adjustments did not have a material effect on current year's net income nor will it have a material effect on future years' net income. The Company accounted for the measurement period adjustment prospectively in 2016 in accordance with ASU No. 2015-16, Business Combinations (Topic 805): Simplifying the Accounting for Measurement-Period Adjustments . Upon completion of purchase accounting, the Company recorded $49.9 million of goodwill in connection with the Merger, which was allocated to the Company's banking reporting unit. The goodwill generated represents the synergies expected from combining operations of the two organizations, including, but not limited to, systems conversion, consolidation of bank locations and operation centers, and reduced headcount across operation teams. The goodwill generated from the transaction is not deductible for tax purposes. Fair value adjustments to assets acquired and liabilities assumed are generally amortized using an effective yield, straight-line basis, or other reasonable method consistent with the expected benefit over periods consistent with the estimated useful life or contractual term of the related assets and liabilities.

Securities

Securities	12 Months Ended
	Dec. 31, 2017
Investments, Debt and Equity Securities [Abstract]
Securities	Securities The following tables summarize the amortized costs and estimated fair values of AFS and HTM securities, as of the dates indicated: Amortized Cost Unrealized Gains Unrealized Losses Fair Value December 31, 2017: AFS Securities: Obligations of states and political subdivisions $ 7,232 $ 103 $ — $ 7,335 Mortgage-backed securities issued or guaranteed by U.S. government-sponsored enterprises 510,176 597 (7,471 ) 503,302 Collateralized mortgage obligations issued or guaranteed by U.S. government-sponsored enterprises 279,575 14 (6,790 ) 272,799 Subordinated corporate bonds 5,484 173 — 5,657 Total AFS debt securities 802,467 887 (14,261 ) 789,093 Equity securities 554 252 — 806 Total AFS securities $ 803,021 $ 1,139 $ (14,261 ) $ 789,899 HTM Securities: Obligations of states and political subdivisions $ 94,073 $ 1,077 $ (237 ) $ 94,913 Total HTM securities $ 94,073 $ 1,077 $ (237 ) $ 94,913 December 31, 2016: AFS Securities: Obligations of states and political subdivisions $ 8,848 $ 153 $ — $ 9,001 Mortgage-backed securities issued or guaranteed by U.S. government-sponsored enterprises 485,222 2,515 (7,115 ) 480,622 Collateralized mortgage obligations issued or guaranteed by U.S. government-sponsored enterprises 289,046 265 (5,421 ) 283,890 Subordinated corporate bonds 5,481 132 — 5,613 Total AFS debt securities 788,597 3,065 (12,536 ) 779,126 Equity securities 632 109 — 741 Total AFS securities $ 789,229 $ 3,174 $ (12,536 ) $ 779,867 HTM Securities: Obligations of states and political subdivisions $ 94,609 $ 618 $ (631 ) $ 94,596 Total HTM securities $ 94,609 $ 618 $ (631 ) $ 94,596 At December 31, 2017 and 2016 , net unrealized losses on AFS securities included in AOCI amounted to $10.3 million , net of a deferred tax benefit of $2.8 million , and $6.1 million , net of a deferred tax benefit of $3.3 million , respectively. Impaired Investment Securities Management periodically reviews the Company’s investment portfolio to determine the cause, magnitude and duration of declines in the fair value of each security. Thorough evaluations of the causes of the unrealized losses are performed to determine whether the impairment is temporary or other-than-temporary in nature. Considerations such as the ability of the securities to meet cash flow requirements, levels of credit enhancements, risk of curtailment, and recoverability of invested amount over a reasonable period of time, and the length of time the security is in a loss position, for example, are applied in determining OTTI. Once a decline in value is determined to be other-than-temporary, the cost basis of the security is permanently reduced and a corresponding charge to earnings is recognized. The following table presents the estimated fair values and gross unrealized losses of investment securities that were in a continuous loss position at December 31, 2017 and 2016 , by length of time that individual securities in each category have been in a continuous loss position: Less Than 12 Months 12 Months or More Total Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses December 31, 2017: AFS Securities: Mortgage-backed securities issued or guaranteed by U.S. government-sponsored enterprises $ 221,466 $ (2,393 ) $ 233,971 $ (5,078 ) $ 455,437 $ (7,471 ) Collateralized mortgage obligations issued or guaranteed by U.S. government-sponsored enterprises 102,612 (696 ) 164,389 (6,094 ) 267,001 (6,790 ) Total AFS securities $ 324,078 $ (3,089 ) $ 398,360 $ (11,172 ) $ 722,438 $ (14,261 ) HTM Securities: Obligations of states and political subdivisions $ 9,317 $ (57 ) $ 9,436 $ (180 ) $ 18,753 $ (237 ) Total HTM securities $ 9,317 $ (57 ) $ 9,436 $ (180 ) $ 18,753 $ (237 ) December 31, 2016: AFS Securities: Mortgage-backed securities issued or guaranteed by U.S. government-sponsored enterprises $ 348,579 $ (5,780 ) $ 29,496 $ (1,335 ) $ 378,075 $ (7,115 ) Collateralized mortgage obligations issued or guaranteed by U.S. government-sponsored enterprises 163,412 (2,906 ) 74,212 (2,515 ) 237,624 (5,421 ) Total AFS securities $ 511,991 $ (8,686 ) $ 103,708 $ (3,850 ) $ 615,699 $ (12,536 ) HTM Securities: Obligations of states and political subdivisions $ 42,805 $ (631 ) $ — $ — $ 42,805 $ (631 ) Total HTM securities $ 42,805 $ (631 ) $ — $ — $ 42,805 $ (631 ) At December 31, 2017 and 2016 , the Company held 209 investment securities with a fair value of $741.2 million and $658.5 million that were in an unrealized loss position totaling $14.5 million and $13.2 million , respectively, that are considered temporary. Of these, MBS and CMOs with a fair value of $398.4 million and $103.7 million were in an unrealized loss position, and have been in an unrealized loss position for 12 months or more totaling $11.2 million and $3.9 million at December 31, 2017 and 2016 , respectively. The decline in the fair value of the debt securities is reflective of current interest rates in excess of the yield received on investments and was not indicative of an overall credit deterioration or other factors with the Company's investment portfolio. At December 31, 2017 and 2016, gross unrealized losses on the Company's AFS and HTM securities were 2% of the respective investment securities fair value. The Company has the intent and ability to retain its investment securities in an unrealized loss position at December 31, 2017 until the decline in value has recovered. Security Gains and Losses and OTTI of Securities The following table details the Company’s sales of AFS investment securities, the gross realized gains and losses, and OTTI of securities: For The Year Ended December 31, 2017 2016 2015 Proceeds from sales of securities $ 20,366 $ 28,850 $ 12,426 Gross realized gains 869 125 221 Gross realized losses (14 ) (74 ) (217 ) Previously recorded OTTI — — 204 For the year ended December 31, 2017 , 2016 , and 2015 , the Company sold certain AFS investment securities with a total carrying value of $19.5 million , $28.8 million , and $12.4 million , respectively, and recorded net gains on the sale of AFS securities of $855,000 , $51,000 , and $4,000 , respectively, within non-interest income in the consolidated statements of income. FHLBB and FRB Stock As of December 31, 2017 and 2016 , the Company's investment in FHLBB stock was $18.3 million and $17.8 million , respectively. At December 31, 2017 and 2016 , the Company's investment in FRB stock was $5.4 million . At December 31, 2017 and 2016, there were no indications of impairment of the Company's investment in FHLBB or FRB stock. For the year ended December 31, 2017, 2016 and 2015, the Company recorded dividend income from its investment in FHLBB and FRB stock of $1.1 million , $1.0 million and $579,000 , respectively. Securities Pledged At December 31, 2017 and 2016 , securities with an amortized cost of $702.5 million and $597.3 million , respectively, and estimated fair values of $691.2 million and $589.7 million , respectively, were pledged to secure FHLBB advances, public deposits, and securities sold under agreements to repurchase, and for other purposes required or permitted by law. Contractual Maturities The amortized cost and estimated fair values of securities by contractual maturity at December 31, 2017 are shown below. Expected maturities will differ from contractual maturities because borrowers may have the right to call or prepay obligations with or without call or prepayment penalties. Amortized Cost Fair Value AFS Securities Due in one year or less $ 4,986 $ 4,983 Due after one year through five years 104,294 103,572 Due after five years through ten years 212,809 209,663 Due after ten years 480,378 470,875 $ 802,467 $ 789,093 HTM Securities Due in one year or less $ 751 $ 751 Due after one year through five years 4,705 4,721 Due after five years through ten years 10,110 10,192 Due after ten years 78,507 79,249 $ 94,073 $ 94,913

Loans and Allowance for Loan Lo

Loans and Allowance for Loan Losses	12 Months Ended
	Dec. 31, 2017
Receivables [Abstract]
Loans and Allowance for Loan Losses	Loans and Allowance for Loan Losses The composition of the Company’s loan portfolio, excluding residential loans held for sale, at December 31, 2017 and 2016 was as follows: December 31, 2017 2016 Residential real estate loans $ 858,369 $ 802,494 Commercial real estate loans 1,164,023 1,050,780 Commercial loans 373,400 333,639 Home equity loans 323,378 329,907 Consumer loans 18,149 17,332 HPFC 45,120 60,412 Total loans $ 2,782,439 $ 2,594,564 The loan balances for each portfolio segment presented above are net of their respective unamortized fair value mark discount on acquired loans and net of unamortized loan origination costs totaling: December 31, 2017 2016 Net unamortized fair value mark discount on acquired loans $ 6,207 $ 8,810 Net unamortized loan origination costs (963 ) (66 ) Total $ 5,244 $ 8,744 The Bank’s lending activities are primarily conducted in Maine, but also include a mortgage loan production office in Massachusetts and a commercial loan production office in New Hampshire. The Company originates single family and multi-family residential loans, commercial real estate loans, business loans, municipal loans and a variety of consumer loans. In addition, the Company makes loans for the construction of residential homes, multi-family properties and commercial real estate properties. The ability and willingness of borrowers to honor their repayment commitments is generally dependent on the level of overall economic activity within the geographic area and the general economy. The HPFC loan portfolio consists of niche commercial lending to the small business medical field, including dentists, optometrists and veterinarians across the U.S. The ability and willingness of borrowers to honor their repayment commitments is generally dependent on the success of the borrower's business. In 2016, the Company closed HPFC's operations and is no longer originating loans. The Bank, in the normal course of business, has made loans to certain officers, directors and their associated companies, under terms that are consistent with the Company’s lending policies and regulatory requirements. Loans, including any unused lines of credit, to related parties were as follows: December 31, 2017 2016 Balance at beginning of year $ 15,942 $ 16,628 Loans made/advanced and additions 230 434 Repayments and reductions (3,032 ) (1,120 ) Balance at end of year $ 13,140 $ 15,942 The ALL is management’s best estimate of the inherent risk of loss in the Company’s loan portfolio as of the consolidated statement of condition date. Management makes various assumptions and judgments about the collectability of the loan portfolio and provides an allowance for potential losses based on a number of factors including historical losses. If those assumptions are incorrect, the ALL may not be sufficient to cover losses and may cause an increase in the allowance in the future. Among the factors that could affect the Company’s ability to collect loans and require an increase to the allowance in the future are: (i) financial condition of borrowers; (ii) real estate market changes; (iii) state, regional, and national economic conditions; and (iv) a requirement by federal and state regulators to increase the provision for loan losses or recognize additional charge-offs. The Board of Directors monitors credit risk through the Directors' Loan Review Committee, which reviews large credit exposures, monitors the external loan review reports, reviews the lending authority for individual loan officers when required, and has approval authority and responsibility for all matters regarding the loan policy and other credit-related policies, including reviewing and monitoring asset quality trends, concentration levels, and the ALL methodology. Credit Risk Administration and the Credit Risk Policy Committee oversee the Company's systems and procedures to monitor the credit quality of its loan portfolio, conduct a loan review program, maintain the integrity of the loan rating system, determine the adequacy of the ALL and support the oversight efforts of the Directors' Loan Review Committee and the Board of Directors. The Company's practice is to proactively manage the portfolio such that management can identify problem credits early, assess and implement effective work-out strategies, and take charge-offs as promptly as practical. In addition, the Company continuously reassesses its underwriting standards in response to credit risk posed by changes in economic conditions. In conjunction with the Company's annual ALL policy review in the fourth quarter of 2017, the Company revised its methodology for calculating the ALL on construction and development loans before reaching permanent financing. This change in ALL methodology did not have a material impact on the Company's reported ALL as of December 31, 2017. For purposes of determining the ALL, the Company disaggregates its loans into portfolio segments, which include residential real estate, commercial real estate, commercial, home equity, consumer and HPFC. Each portfolio segment possesses unique risk characteristics that are considered when determining the appropriate level of allowance. These risk characteristics unique to each portfolio segment include: Residential Real Estate . Residential real estate loans held in the Company's loan portfolio are made to borrowers who demonstrate the ability to make scheduled payments with full consideration to underwriting factors. Borrower qualifications include favorable credit history combined with supportive income requirements and combined loan-to-value ratios within established policy guidelines. Collateral consists of mortgage liens on one- to four-family residential properties. Commercial Real Estate. Commercial real estate loans consist of mortgage loans to finance investments in real property such as multi-family residential, commercial/retail, office, industrial, hotels, educational, health care facilities and other specific use properties. Commercial real estate loans are typically written with amortizing payment structures. Collateral values are determined based upon appraisals and evaluations in accordance with established policy guidelines. Loan-to-value ratios at origination are governed by established policy and regulatory guidelines. Commercial real estate loans are primarily paid by the cash flow generated from the real property, such as operating leases, rents, or other operating cash flows from the borrower. Commercial. Commercial loans consist of revolving and term loan obligations extended to business and corporate enterprises for the purpose of financing working capital and/or capital investment. Collateral generally consists of pledges of business assets including, but not limited to, accounts receivable, inventory, plant and equipment, and/or real estate, if applicable. Commercial loans are primarily paid by the operating cash flow of the borrower. Commercial loans may be secured or unsecured. Home Equity. Home equity loans and lines are made to qualified individuals for legitimate purposes secured by senior or junior mortgage liens on owner-occupied one- to four-family homes, condominiums, or vacation homes. The home equity loan has a fixed rate and is billed as equal payments comprised of principal and interest. The home equity line of credit has a variable rate and is billed as interest-only payments during the draw period. At the end of the draw period, the home equity line of credit is billed as a percentage of the principal balance plus all accrued interest. Borrower qualifications include favorable credit history combined with supportive income requirements and combined loan-to-value ratios within established policy guidelines. Consumer. Consumer loan products including personal lines of credit and amortizing loans made to qualified individuals for various purposes such as education, auto loans, debt consolidation, personal expenses or overdraft protection. Borrower qualifications include favorable credit history combined with supportive income and collateral requirements within established policy guidelines. Consumer loans may be secured or unsecured. HPFC. Prior to the Company's closing of HPFC's operations in 2016, it provided commercial lending to dentists, optometrists and veterinarians, many of which were start-up companies. HPFC's loan portfolio consists of term loan obligations extended for the purpose of financing working capital and/or purchase of equipment. Collateral consists of pledges of business assets including, but not limited to, accounts receivable, inventory, and/or equipment. These loans are primarily paid by the operating cash flow of the borrower and the terms range from seven to ten years. The following table presents the activity in the ALL and select loan information by portfolio segment for the year ended December 31, 2017 , 2016 , and 2015 : Residential Real Estate Commercial Real Estate Commercial Home Equity Consumer HPFC Unallocated Total For The Year Ended December 31, 2017: ALL: Beginning balance $ 4,160 $ 12,154 $ 3,755 $ 2,194 $ 181 $ 672 $ — $ 23,116 Loans charged off (482 ) (124 ) (1,014 ) (434 ) (124 ) (290 ) — (2,468 ) Recoveries 30 141 301 2 17 6 — 497 Provision (credit) (1) 1,378 (308 ) 1,129 605 159 63 — 3,026 Ending balance $ 5,086 $ 11,863 $ 4,171 $ 2,367 $ 233 $ 451 $ — $ 24,171 ALL balance attributable loans: Individually evaluated for impairment $ 568 $ 1,441 $ — $ — $ — $ — $ — $ 2,009 Collectively evaluated for impairment 4,518 10,422 4,171 2,367 233 451 — 22,162 Total ending ALL $ 5,086 $ 11,863 $ 4,171 $ 2,367 $ 233 $ 451 $ — $ 24,171 Loans: Individually evaluated for impairment $ 5,171 $ 6,199 $ 1,791 $ 429 $ — $ — $ — $ 13,590 Collectively evaluated for impairment 853,198 1,157,824 371,609 322,949 18,149 45,120 — 2,768,849 Total loan balances $ 858,369 $ 1,164,023 $ 373,400 $ 323,378 $ 18,149 $ 45,120 $ — $ 2,782,439 For The Year Ended December 31, 2016: ALL: Beginning balance $ 4,545 $ 10,432 $ 3,241 $ 2,731 $ 193 $ 24 $ — $ 21,166 Loans charged off (356 ) (315 ) (2,218 ) (308 ) (101 ) (507 ) — (3,805 ) Recoveries 95 50 332 2 7 — — 486 Provision (credit) (1) (124 ) 1,987 2,400 (231 ) 82 1,155 — 5,269 Ending balance $ 4,160 $ 12,154 $ 3,755 $ 2,194 $ 181 $ 672 $ — $ 23,116 ALL balance attributable loans: Individually evaluated for impairment $ 483 $ 1,373 $ — $ 86 $ — $ 65 $ — $ 2,007 Collectively evaluated for impairment 3,677 10,781 3,755 2,108 181 607 — 21,109 Total ending ALL $ 4,160 $ 12,154 $ 3,755 $ 2,194 $ 181 $ 672 $ — $ 23,116 Loans: Individually evaluated for impairment $ 4,348 $ 13,317 $ 2,028 $ 457 $ 7 $ 97 $ — $ 20,254 Collectively evaluated for impairment 798,146 1,037,463 331,611 329,450 17,325 60,315 — 2,574,310 Total loan balances $ 802,494 $ 1,050,780 $ 333,639 $ 329,907 $ 17,332 $ 60,412 $ — $ 2,594,564 Residential Real Estate Commercial Real Estate Commercial Home Equity Consumer HPFC Unallocated Total For The Year Ended December 31, 2015: ALL: Beginning balance $ 4,899 $ 7,951 $ 3,354 $ 2,247 $ 281 $ — $ 2,384 $ 21,116 Loans charged off (801 ) (481 ) (655 ) (525 ) (154 ) — — (2,616 ) Recoveries 55 74 389 188 22 — — 728 Provision (credit) (1) 392 2,888 153 821 44 24 (2,384 ) 1,938 Ending balance $ 4,545 $ 10,432 $ 3,241 $ 2,731 $ 193 $ 24 $ — $ 21,166 ALL balance attributable loans: Individually evaluated for impairment $ 544 $ 644 $ 92 $ 89 $ — $ — $ — $ 1,369 Collectively evaluated for impairment 4,001 9,788 3,149 2,642 193 24 — 19,797 Total ending ALL $ 4,545 $ 10,432 $ 3,241 $ 2,731 $ 193 $ 24 $ — $ 21,166 Loans: Individually evaluated for impairment $ 6,026 $ 4,610 $ 3,937 $ 588 $ 74 $ — $ — $ 15,235 Collectively evaluated for impairment 814,591 923,341 293,784 348,046 17,879 77,330 — 2,474,971 Total loan balances $ 820,617 $ 927,951 $ 297,721 $ 348,634 $ 17,953 $ 77,330 $ — $ 2,490,206 (1) The provision (credit) for loan losses excludes any impact for the change in the reserve for unfunded commitments, which represents management's estimate of the amount required to reflect the probable inherent losses on outstanding letters of credit and unused lines of credit. The reserve for unfunded commitments is presented within accrued interest and other liabilities on the consolidated statements of condition. At December 31, 2017 , 2016 , and 2015 , the reserve for unfunded commitments was $20,000 , $11,000 and $22,000 , respectively. The following table reconciles the year ended December 31, 2017 , 2016 , and 2015 provision for loan losses to the provision for credit losses as presented on the consolidated statement of income: For the Year Ended December 31, 2017 2016 2015 Provision for loan losses $ 3,026 $ 5,269 $ 1,938 Change in reserve for unfunded commitments 9 (11 ) (2 ) Provision for credit losses $ 3,035 $ 5,258 $ 1,936 The Company focuses on maintaining a well-balanced and diversified loan portfolio. Despite such efforts, it is recognized that credit concentrations may occasionally emerge as a result of economic conditions, changes in local demand, natural loan growth and runoff. To ensure that credit concentrations can be effectively identified, all commercial and commercial real estate loans are assigned Standard Industrial Classification codes, North American Industry Classification System codes, and state and county codes. Shifts in portfolio concentrations are monitored by the Company's Credit Risk Administration. As of December 31, 2017 , the non-residential building operators' industry concentration was 11% of the Company's total loan portfolio and 27% of the total commercial real estate portfolio. There were no other industry concentrations exceeding 10% of the Company's total loan portfolio as of December 31, 2017 . To further identify loans with similar risk profiles, the Company categorizes each portfolio segment into classes by credit risk characteristic and applies a credit quality indicator to each portfolio segment. The indicators for commercial, commercial real estate and residential real estate loans are represented by Grades 1 through 10 as outlined below. In general, risk ratings are adjusted periodically throughout the year as updated analysis and review warrants. This process may include, but is not limited to, annual credit and loan reviews, periodic reviews of loan performance metrics, such as delinquency rates, and quarterly reviews of adversely risk rated loans. The Company uses the following definitions when assessing grades for the purpose of evaluating the risk and adequacy of the ALL: • Grade 1 through 6 — Grades 1 through 6 represent groups of loans that are not subject to adverse criticism as defined in regulatory guidance. Loans in these groups exhibit characteristics that represent low to moderate risks, which is measured using a variety of credit risk criteria, such as cash flow coverage, debt service coverage, balance sheet leverage, liquidity, management experience, industry position, prevailing economic conditions, support from secondary sources of repayment and other credit factors that may be relevant to a specific loan. In general, these loans are supported by properly margined collateral and guarantees of principal parties. • Grade 7 — Loans with potential weakness (Special Mention). Loans in this category are currently protected based on collateral and repayment capacity and do not constitute undesirable credit risk, but have potential weakness that may result in deterioration of the repayment process at some future date. This classification is used if a negative trend is evident in the obligor’s financial situation. Special mention loans do not sufficiently expose the Company to warrant adverse classification. • Grade 8 — Loans with definite weakness (Substandard). Loans classified as substandard are inadequately protected by the current sound worth and paying capacity of the obligor or by collateral pledged. Borrowers experience difficulty in meeting debt repayment requirements. Deterioration is sufficient to cause the Company to look to the sale of collateral. • Grade 9 — Loans with potential loss (Doubtful). Loans classified as doubtful have all the weaknesses inherent in the substandard grade with the added characteristic that the weaknesses make collection or liquidation of the loan in full highly questionable and improbable. The possibility of some loss is extremely high, but because of specific pending factors that may work to the advantage and strengthening of the asset, its classification as an estimated loss is deferred until its more exact status may be determined. • Grade 10 — Loans with definite loss (Loss). Loans classified as loss are considered uncollectible. The loss classification does not mean that the asset has absolutely no recovery or salvage value, but rather that it is not practical or desirable to defer writing off the asset because recovery and collection time may be protracted. Asset quality indicators are periodically reassessed to appropriately reflect the risk composition of the Company’s loan portfolio. Home equity and consumer loans are not individually risk rated, but rather analyzed as groups taking into account delinquency rates and other economic conditions which may affect the ability of borrowers to meet debt service requirements, including interest rates and energy costs. Performing loans include loans that are current and loans that are past due less than 90 days. Loans that are past due over 90 days and non-accrual loans, including TDRs, are considered non-performing. The following table summarizes credit risk exposure indicators by portfolio segment as of the following dates: Residential Real Estate Commercial Real Estate Commercial Home Equity Consumer HPFC Total December 31, 2017: Pass (Grades 1 – 6) $ 846,394 $ 1,130,235 $ 354,904 $ — $ — $ 43,049 $ 2,374,582 Performing — — — 321,727 18,149 — 339,876 Special Mention (Grade 7) 922 9,154 12,517 — — 191 22,784 Substandard (Grade 8) 11,053 24,634 5,979 — — 1,880 43,546 Non-performing — — — 1,651 — — 1,651 Total $ 858,369 $ 1,164,023 $ 373,400 $ 323,378 $ 18,149 $ 45,120 $ 2,782,439 December 31, 2016: Pass (Grades 1 – 6) $ 789,554 $ 1,003,386 $ 321,148 $ — $ — $ 58,943 $ 2,173,031 Performing — — — 328,287 17,328 — 345,615 Special Mention (Grade 7) 2,387 5,724 5,598 — — 257 13,966 Substandard (Grade 8) 10,553 41,670 5,437 — — 1,212 58,872 Doubtful (Grade 9) — — 1,456 — — — 1,456 Non-performing — — — 1,620 4 — 1,624 Total $ 802,494 $ 1,050,780 $ 333,639 $ 329,907 $ 17,332 $ 60,412 $ 2,594,564 The Company closely monitors the performance of its loan portfolio. A loan is placed on non-accrual status when the financial condition of the borrower is deteriorating, payment in full of both principal and interest is not expected as scheduled or principal or interest has been in default for 90 days or more. Exceptions may be made if the asset is well-secured by collateral sufficient to satisfy both the principal and accrued interest in full and collection is reasonably assured. When one loan to a borrower is placed on non-accrual status, all other loans to the borrower are re-evaluated to determine if they should also be placed on non-accrual status. All previously accrued and unpaid interest is reversed at this time. A loan will return to accrual status when collection of principal and interest is assured and the borrower has demonstrated timely payments of principal and interest for a reasonable period. Unsecured loans, however, are not normally placed on non-accrual status because they are charged-off once their collectability is in doubt. The following is a loan aging analysis by portfolio segment (including loans past due over 90 days and non-accrual loans) and a summary of non-accrual loans, which include TDRs, and loans past due over 90 days and accruing as of the following dates: 30 – 59 Days Past Due 60 – 89 Days Past Due Greater Than 90 Days Total Past Due Current Total Loans Outstanding Loans > 90 Days Past Due and Accruing Non-Accrual Loans December 31, 2017: Residential real estate $ 3,871 $ 1,585 $ 4,021 $ 9,477 $ 848,892 $ 858,369 $ — $ 4,979 Commercial real estate 849 323 5,528 6,700 1,157,323 1,164,023 — 5,642 Commercial 329 359 1,535 2,223 371,177 373,400 — 2,000 Home equity 1,046 173 1,329 2,548 320,830 323,378 — 1,650 Consumer 57 10 — 67 18,082 18,149 — — HPFC 139 1,372 419 1,930 43,190 45,120 — 1,043 Total $ 6,291 $ 3,822 $ 12,832 $ 22,945 $ 2,759,494 $ 2,782,439 $ — $ 15,314 December 31, 2016: Residential real estate $ 1,783 $ 924 $ 2,904 $ 5,611 $ 796,883 $ 802,494 $ — $ 3,945 Commercial real estate 855 223 12,625 13,703 1,037,077 1,050,780 — 12,849 Commercial 633 218 1,675 2,526 331,113 333,639 — 2,088 Home equity 892 134 1,321 2,347 327,560 329,907 — 1,620 Consumer 38 — 4 42 17,290 17,332 — 4 HPFC 438 688 110 1,236 59,176 60,412 — 207 Total $ 4,639 $ 2,187 $ 18,639 $ 25,465 $ 2,569,099 $ 2,594,564 $ — $ 20,713 Interest income that would have been recognized if loans on non-accrual status had been current in accordance with their original terms for the year ended December 31, 2017 , 2016 , and 2015 was $843,000 , $888,000 , and $586,000 , respectively. TDRs: The Company takes a conservative approach with credit risk management and remains focused on community lending and reinvesting. The Company works closely with borrowers experiencing credit problems to assist in loan repayment or term modifications. TDR loans consist of loans where the Company, for economic or legal reasons related to the borrower’s financial difficulties, granted a concession to the borrower that it would not otherwise consider. TDRs, typically, involve term modifications or a reduction of either interest or principal. Once such an obligation has been restructured, it will remain a TDR until paid in full, or until the loan is again restructured at current market rates and no concessions are granted. The specific reserve allowance was determined by discounting the total expected future cash flows from the borrower at the original loan interest rate, or if the loan is currently collateral-dependent, using the net realizable value, which was obtained through independent appraisals and internal evaluations. The following is a summary of TDRs, by portfolio segment, and the associated specific reserve included within the ALL as of December 31: Number of Contracts Recorded Investment Specific Reserve 2017 2016 2017 2016 2017 2016 Residential real estate 24 21 $ 3,604 $ 3,221 $ 452 $ 483 Commercial real estate 3 3 976 1,008 16 — Commercial 7 10 1,345 1,502 — — Consumer and home equity 2 1 307 16 — — Total 36 35 $ 6,232 $ 5,747 $ 468 $ 483 At December 31, 2017 , the Company had performing and non-performing TDRs with a recorded investment balance of $5.0 million and $1.2 million , respectively. At December 31, 2016 , the Company had performing and non-performing TDRs with a recorded investment balance of $4.3 million and $1.4 million , respectively. The following represents loan modifications that occurred for the year ended December 31, 2017 , 2016 and 2015 that qualify as TDRs and the type of loan modification made by portfolio segment at December 31: Number of Contracts Pre-Modification Outstanding Recorded Investment Post-Modification Outstanding Recorded Investment Specific Reserve 2017 2016 2015 2017 2016 2015 2017 2016 2015 2017 2016 2015 Residential real estate: Maturity concession 2 — — $ 298 $ — $ — $ 298 $ — $ — $ 15 $ — $ — Court ordered — — 1 — — 74 — — 78 — — 27 Interest rate concession 1 — — 134 — — 145 — — — — — Interest rate and maturity concession 1 — — 148 — — 156 — — 30 — — Commercial: Maturity concession — 6 — — 2,973 — — 2,973 — — 1,400 — Home equity: Interest rate and maturity concession 1 — — 315 — — 315 — — — — — Total 5 6 1 $ 895 $ 2,973 $ 74 $ 914 $ 2,973 $ 78 $ 45 $ 1,400 $ 27 In 2016, the Company completed the restructure of one commercial relationship, which included six individual commercial loans, and recorded a specific reserve of $1.4 million at the time of the restructure. In 2016, subsequent to the loan modification, the $1.4 million specific reserve established on the relationship was fully charged-off and, at December 31, 2017 and 2016, the Company did not carry a specific reserve on this relationship. As part of the restructure, the Company committed to lend additional funds of up to $280,000 . At December 31, 2017 and 2016, the Company had loaned $22,000 and $47,000 , respectively, on its commitment. The Company did no t have any other commitments to lend additional funds to borrowers with loans classified as TDRs as of December 31, 2017. For the year ended December 31, 2017, 2016 and 2015, the Company did no t have any loans that had been modified as a TDR within the previous 12 months and for which the borrower subsequently defaulted for the periods indicated. Impaired Loans: Impaired loans consist of non-accrual and TDR loans that are individually evaluated for impairment in accordance with the Company's policy. The following is a summary of impaired loan balances and the associated allowance by portfolio segment as of and for the year ended December 31, 2017 , 2016 and 2015 : Recorded Investment Unpaid Principal Balance Related Allowance Average Recorded Investment Interest Income Recognized December 31, 2017: With related allowance recorded: Residential real estate $ 3,858 $ 3,858 $ 568 $ 3,177 $ 131 Commercial real estate 5,422 5,422 1,441 8,900 22 Commercial — — — 31 — Home equity — — — 125 — Consumer — — — — — HPFC — — — 24 — Ending balance 9,280 9,280 2,009 12,257 153 Without related allowance recorded: Residential real estate 1,313 1,673 — 1,345 15 Commercial real estate 777 1,084 — 1,132 29 Commercial 1,791 2,964 — 1,920 10 Home equity 429 495 — 310 8 Consumer — — — 2 — HPFC — — — — — Ending balance 4,310 6,216 — 4,709 62 Total impaired loans $ 13,590 $ 15,496 $ 2,009 $ 16,966 $ 215 December 31, 2016: With related allowance recorded: Residential real estate $ 3,019 $ 3,019 $ 483 $ 3,088 $ 106 Commercial real estate 11,443 11,443 1,373 5,165 — Commercial — — — 762 — Home equity 299 299 86 305 — Consumer — — — — — HPFC 97 97 65 98 — Ending balance 14,858 14,858 2,007 9,418 106 Without related allowance recorded: Residential real estate 1,329 1,800 — 2,057 9 Commercial real estate 1,874 2,369 — 2,214 51 Commercial 2,028 3,209 — 2,507 16 Home equity 158 368 — 180 — Consumer 7 10 — 12 — HPFC — — — — — Ending balance 5,396 7,756 — 6,970 76 Total impaired loans $ 20,254 $ 22,614 $ 2,007 $ 16,388 $ 182 Recorded Investment Unpaid Principal Balance Related Allowance Average Recorded Investment Interest Income Recognized December 31, 2015: With related allowance recorded: Residential real estate $ 3,191 $ 3,191 $ 544 $ 6,064 $ 112 Commercial real estate 1,825 1,857 644 1,753 — Commercial 156 156 92 945 2 Home equity 303 303 89 900 — Consumer — — — 195 — HPFC — — — — — Ending balance 5,475 5,507 1,369 9,857 114 Without related allowance recorded: Residential real estate 2,835 4,353 — 2,175 8 Commercial real estate 2,785 3,426 — 2,719 65 Commercial 3,781 4,325 — 1,412 17 Home equity 285 688 — 369 — Consumer 74 150 — 20 — HPFC — — — — — Ending balance 9,760 12,942 — 6,695 90 Total impaired loans $ 15,235 $ 18,449 $ 1,369 $ 16,552 $ 204 In-Process Foreclosure Proceedings: At December 31, 2017 and 2016 , the Company had $1.9 million and $1.4 million of consumer mortgage loans secured by residential real estate properties for which foreclosure proceedings were in process. The Company continues to be focused on working these consumer mortgage loans through the foreclosure process to resolution; however, the foreclosure process, typically, will take 18 to 24 months due to the State of Maine foreclosure laws.

Goodwill

Goodwill	12 Months Ended
	Dec. 31, 2017
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill	Goodwill The changes in goodwill for the year ended December 31, 2017 and 2016 for each reporting unit are shown in the table below: Banking Financial Services Total Balance as of January 1, 2016: Goodwill $ 91,753 $ 7,474 $ 99,227 Accumulated impairment losses — (3,570 ) (3,570 ) Reported goodwill 91,753 3,904 95,657 Measurement-period adjustment (Note 2) (960 ) — (960 ) Balance as of December 31, 2016: Goodwill 90,793 7,474 98,267 Accumulated impairment losses — (3,570 ) (3,570 ) Reported goodwill $ 90,793 $ 3,904 $ 94,697 Balance as of January 1 and December 31, 2017: Goodwill $ 90,793 $ 7,474 $ 98,267 Accumulated impairment losses — (3,570 ) (3,570 ) Reported goodwill $ 90,793 $ 3,904 $ 94,697 The Company performs its annual goodwill impairment assessment as of November 30 th , and at interim periods if indicators of potential impairment exist. The Company completed its annual goodwill impairment test as of November 30, 2017 , 2016 and 2015 for each reporting unit and determined there was no goodwill impairment. Other Intangible Assets The gross carrying amount and accumulated amortization of other intangible assets were as follows at the periods indicated: December 31, 2017 2016 Gross Carrying Amount Accumulated Amortization Net Carrying Amount Gross Carrying Amount Accumulated Amortization Net Carrying Amount Core deposit intangible $ 23,908 $ (18,953 ) $ 4,955 $ 23,908 $ (17,220 ) $ 6,688 Trust relationship intangible 753 (753 ) — 753 (677 ) 76 Total $ 24,661 $ (19,706 ) $ 4,955 $ 24,661 $ (17,897 ) $ 6,764 For the year ended December 31, 2017 , 2016 and 2015 , the Company recorded amortization expense of $1.8 million , $1.9 million and $1.3 million , respectively. The following table reflects the expected amortization schedule for other intangible assets over the period of estimated economic benefit (assuming no additional intangible assets are created or impaired): Core Deposit Intangible 2018 $ 725 2019 705 2020 682 2021 655 2022 625 Thereafter 1,563 Total $ 4,955

Other Intangible Assets

Other Intangible Assets	12 Months Ended
	Dec. 31, 2017
Other Intangible Assets [Abstract]
Other Intangibles Assets	Goodwill The changes in goodwill for the year ended December 31, 2017 and 2016 for each reporting unit are shown in the table below: Banking Financial Services Total Balance as of January 1, 2016: Goodwill $ 91,753 $ 7,474 $ 99,227 Accumulated impairment losses — (3,570 ) (3,570 ) Reported goodwill 91,753 3,904 95,657 Measurement-period adjustment (Note 2) (960 ) — (960 ) Balance as of December 31, 2016: Goodwill 90,793 7,474 98,267 Accumulated impairment losses — (3,570 ) (3,570 ) Reported goodwill $ 90,793 $ 3,904 $ 94,697 Balance as of January 1 and December 31, 2017: Goodwill $ 90,793 $ 7,474 $ 98,267 Accumulated impairment losses — (3,570 ) (3,570 ) Reported goodwill $ 90,793 $ 3,904 $ 94,697 The Company performs its annual goodwill impairment assessment as of November 30 th , and at interim periods if indicators of potential impairment exist. The Company completed its annual goodwill impairment test as of November 30, 2017 , 2016 and 2015 for each reporting unit and determined there was no goodwill impairment. Other Intangible Assets The gross carrying amount and accumulated amortization of other intangible assets were as follows at the periods indicated: December 31, 2017 2016 Gross Carrying Amount Accumulated Amortization Net Carrying Amount Gross Carrying Amount Accumulated Amortization Net Carrying Amount Core deposit intangible $ 23,908 $ (18,953 ) $ 4,955 $ 23,908 $ (17,220 ) $ 6,688 Trust relationship intangible 753 (753 ) — 753 (677 ) 76 Total $ 24,661 $ (19,706 ) $ 4,955 $ 24,661 $ (17,897 ) $ 6,764 For the year ended December 31, 2017 , 2016 and 2015 , the Company recorded amortization expense of $1.8 million , $1.9 million and $1.3 million , respectively. The following table reflects the expected amortization schedule for other intangible assets over the period of estimated economic benefit (assuming no additional intangible assets are created or impaired): Core Deposit Intangible 2018 $ 725 2019 705 2020 682 2021 655 2022 625 Thereafter 1,563 Total $ 4,955

Premises and Equipment

Premises and Equipment	12 Months Ended
	Dec. 31, 2017
Property, Plant and Equipment [Abstract]
Premises and Equipment	Premises and Equipment Details of premises and equipment, at cost, for the periods indicated, were as follows: 2017 2016 Land and land improvements $ 2,985 $ 3,012 Buildings and leasehold improvements 37,054 36,958 Furniture, fixtures and equipment 36,053 34,043 Total cost 76,092 74,013 Accumulated depreciation and amortization (34,201 ) (31,140 ) Net premises and equipment $ 41,891 $ 42,873 Depreciation and amortization expense for the periods indicated were as follows: For The Year Ended December 31, Fixed Asset Type Income Statement Line Item 2017 2016 2015 Equipment and data Furniture, equipment and data processing $ 1,874 $ 1,942 $ 1,620 Premises Net occupancy costs 1,643 1,757 1,140 Software Furniture, equipment and data processing 244 275 337 Equipment, data and premises Merger and acquisition costs — 452 517 Total $ 3,761 $ 4,426 $ 3,614 At December 31, 2017 and 2016 , the Company has capitalized software costs of $ 3.8 million and $3.6 million , respectively, and related accumulated depreciation expense of $3.5 million and $3.2 million , respectively, and was presented within other assets on the consolidated statements of condition. Included in merger and acquisition costs on the consolidated statements of income for the year ended December 31, 2015 was $1.1 million of fixed asset disposal costs incurred as a result of the acquisition of SBM. The Company did no t have any material gains or losses from the sale of premises and equipment for the year ended December 31, 2017, 2016 or 2015. The Company enters into noncancellable lease arrangements primarily for its office buildings and branches. Certain lease arrangements contain clauses requiring increasing rental payments over the lease term, which may be indexed to an index (commonly the Consumer Price Index) or the increases may be contractually stipulated. Furthermore, many of these lease arrangements provide the Company with the option to renew the lease arrangement after the initial lease term. The Company incurred expenses of $1.5 million , $1.8 million and $1.7 million for the year ended December 31, 2017 , 2016 and 2015 , respectively, associated with its operating lease arrangements. The Company has one capital lease for a branch with payments that extend until 2026 at an interest rate of 9.75% per year. The capital lease, recorded in premises and equipment, has a cost basis of $855,000 at December 31, 2017 and 2016 and accumulated depreciation of $502,000 and $459,000 at December 31, 2017 and 2016 , respectively. The associated depreciation expense was reported within net occupancy costs on the consolidated statements of income. In connection with the SBM acquisition, the Company assumed a lease arrangement between SBM wholly-owned subsidiary, The Bank of Maine, and two of its employees. The lease is for a period of five years with an expiration date of December 1, 2019 with two consecutive five year extension periods available at the option of the Company. The lease arrangement contains certain termination clauses whereby the Company has the right to terminate the lease arrangement should the employees be terminated and/or certain mortgage loan production metrics not be met over a consecutive 12 month period. At December 31, 2017 , under current operating and capital lease contracts, the Company had the following schedule of future minimum lease payments: Operating Capital 2018 $ 1,429 $ 126 2019 1,394 126 2020 888 126 2021 671 130 2022 484 131 Thereafter 1,531 425 Total minimum lease payments $ 6,397 1,064 Less: amount representing interest (1) 273 Present value of net minimum lease payments (2) $ 791 (1) Amount necessary to reduce net minimum lease payments to present value calculated at the Company's incremental borrowing rate at lease inception. (2) Reflects the liability reported within short- and long-term borrowings on the consolidated statements of condition. At December 31, 2017 and 2016 , the capital lease liability was $791,000 and $858,000 , respectively.

Mortgage Banking

Mortgage Banking	12 Months Ended
	Dec. 31, 2017
Transfers and Servicing [Abstract]
Mortgage Banking	Mortgage Banking Loans Sold For the year ended December 31, 2017, 2016 and 2015, the Company sold $218.6 million , $232.2 million and $61.2 million , respectively, of residential mortgage loans on the secondary market, which resulted in a net gain on sale of loans (net of costs, including direct and indirect origination costs) of $6.3 million , $6.2 million , and $1.3 million , respectively. Loans Held for Sale At December 31, 2017 and 2016, the Company had identified and designated loans with an unpaid principal balance of $8.1 million and $15.1 million , respectively, as held for sale. The Company has elected the fair value option for its loans designated as held for sale, and, at December 31, 2017 and 2016, the unrealized gain (loss) recorded was $37,000 and ( $289,000 ), respectively. The unrealized gain or loss on its loans held for sale portfolio was driven by changes in market interest rates and not due to deteriorated credit quality as this risk is mitigated by the short duration between the time of the loan closed and transfer of the financial assets to the secondary market investor. Included within the Company's mortgage banking income, net on its consolidated statements of income for the year ended December 31, 2017, 2016 and 2015 was the change in unrealized gains (losses) on loans held for sale of $326,000 , $(422,000) and $133,000 , respectively. The Company mitigates its interest rate exposure on its loans designated as held for sale through forward delivery commitments with certain approved secondary market investors at the onset of the mortgage origination process, typically on a best-efforts basis. For the year ended December 31, 2017, 2016 and 2015, the Company recorded gains (losses) on its forward delivery commitments of ($136,000) , $278,000 , and $0 , respectively. Refer to Note 18 for further discussion of the Company's forward delivery commitments. Servicing Assets At December 31, 2017 and 2016, the Company's unpaid principal balances on its servicing assets were $275.2 million and $332.7 million, respectively. For the year ended December 31, 2017, 2016 and 2015, the Company recorded servicing fee income for its servicing assets of $1.0 million , $1.1 million and $597,000 , respectively, and was presented in mortgage banking income, net on the consolidated statements of income. The Company's servicing assets, net of a valuation allowance, included in other assets on the consolidated statements of condition at December 31, 2017 and 2016 was $1.0 million and $1.2 million , respectively. The Company obtains third party valuations of its servicing assets portfolio quarterly. The servicing assets valuation is based on loan level data stratified by note rate of the underlying loans to determine its amortization and fair value. A discounted cash flow model is used to value each servicing asset strata and it incorporates current market assumption commonly used by buyers of these types of mortgage production in U.S. servicing markets. The calculated valuation using the discounted cash flow method is then compared to recent servicing trades on portfolios with similar characteristics in the U.S. The valuation model utilizes a variety of assumptions, the most significant of which are loan prepayment assumptions and the discount rate used to discount future cash flows. At December 31, 2017 and 2016 , the prepayment assumption used within the valuation model was 14.0% and 14.6% , respectively, and the discount rate was 11.2% and 7.8% . The estimated effect of a 10% and 20% increase to the prepayment assumption at December 31, 2017 was a decrease of $76,000 and $148,000 , respectively, while a 100 and 200 basis points increase to the discount rate assumption was a decrease of $54,000 and $105,000 . Other assumptions include, but are not limited to, delinquency rates, foreclosure rates, and loan servicing cost. The following summarizes servicing assets capitalized and amortized, along with the activity in the related valuation allowance: As of and For The Year Ended December 31, 2017 2016 2015 Servicing Assets: Balance at beginning of year $ 1,210 $ 2,161 $ 493 Capitalized servicing right fees upon sale (1) 22 9 294 Acquired in connection with acquisition of SBM, at fair value — — 1,608 Amortization charged against mortgage servicing fee income (1) (430 ) (734 ) (231 ) Valuation adjustment 223 (226 ) (3 ) Balance at end of year $ 1,025 $ 1,210 $ 2,161 Valuation Allowance: Balance at beginning of year $ (230 ) $ (4 ) $ (1 ) (Increase) decrease in impairment reserve (1) 223 (226 ) (3 ) Balance at end of year $ (7 ) $ (230 ) $ (4 ) Fair value, beginning of year $ 1,701 $ 2,947 $ 1,447 Fair value, end of year $ 1,766 $ 1,701 $ 2,947 (1) Reported within mortgage banking income, net on the Company's consolidated statements of income. Sub-Serviced Loans Mortgage loans serviced for third party investors, for which the Company acts in a sub-servicer capacity and, therefore, does not have a corresponding servicing asset, are not reported as assets of the Company on its consolidated statements of condition. The unpaid principal balance on mortgage loans serviced for investors at December 31, 2017 and 2016 was $349.7 million and $930.8 million , respectively. Custodial escrow balances maintained in connection with the foregoing loan servicing for investors, and included in demand deposits on the Company's consolidated statements of condition, were $4.2 million and $11.9 million at December 31, 2017 and 2016 , respectively. The Company recognized sub-servicing fee income, including related loan fees, for the years ended December 31, 2017, 2016 and 2015 of $12,000 , $1.7 million , and $1.2 million . Effective close of business on December 31, 2016, the Company exited a significant sub-servicer relationship. As part of its agreement to service loans for investors and its own loan portfolio, the Company is required to ensure the good-standing and priority lien position of the collateral for its mortgage loans. In doing so, the Company will advance borrower escrows and incur certain costs that are reimbursable by the borrowers, investors or other means, including mortgage insurance companies and governmental-backed agencies. At December 31, 2017 and 2016, the Company advanced escrow balances of $194,000 and $2.0 million , respectively, and had a receivable of $58,000 and $2.7 million , respectively, for the aforementioned services. At December 31, 2017 and 2016, the Company carried an allowance on the aforementioned receivable of $0 and $829,000 , respectively. The Company estimated the allowance on its receivable utilizing historical claim and reimbursement information, as well as information through ongoing negotiations with its investors. The Company has presented its advanced escrows and aforementioned net receivable within other assets on the Company's consolidated statements of condition. In addition to fees earned for servicing the portfolios of investors, servicer guides impose certain time-lines for resolving delinquent loans through workout efforts or liquidation and impose compensatory fees on the Company if those deadlines are not satisfied other than for reasons beyond our control. The investors also have a contractual right to demand indemnification or loan repurchase for certain servicing breaches. For example, the Company would be required to indemnify the investors for or against failures by the Company to perform its servicing obligations or acts or omissions that involve willful malfeasance, bad faith or gross negligence in the performance of, or reckless disregard of, its duties. The Company records expenses for servicing-related claims and loan repurchases when it is probable that such claims or repurchases will be made and the amounts are reasonably estimable. Servicer and Sub-Servicer Net Worth and Liquidity Requirements The Bank, as a servicer and sub-servicer of loans, must maintain certain net worth and liquidity requirements for certain secondary market investors, including the U.S. Department of Housing and Urban Development ("HUD"), the Federal National Mortgage Association ("FNMA") and the Federal Home Loan Mortgage Corporation ("FHLMC"). The Bank is required to maintain a minimum net worth of $1.0 million plus 1.0% of total Federal Housing Authority ("FHA") loans exceeding $25.0 million ("minimum net worth required") and maintain liquid assets equal to at least 20.0% of its minimum net worth required. The Bank is required to maintain a minimum net worth of $2.5 million plus 25 basis points of the unpaid principal balance of serviced loans and must meet the minimum regulatory capital requirement to be classified as "well capitalized" by both FNMA and FHLMC. Should the Bank fail to maintain the net worth and liquidity requirements above, the secondary market investor may take remedial action and the Company may lose the right to service the loans, which may result in an impairment of its servicing assets and/or loss of revenue but would not materially affect the Company's consolidated financial statements. At December 31, 2017 and 2016, the Bank met all of the aforementioned minimum net worth, regulatory capital, and liquidity requirements. Refer to Note 13 for further details of the Company and Bank's regulatory capital requirements at December 31, 2017 and 2016.

Deposits

Deposits	12 Months Ended
	Dec. 31, 2017
Deposits [Abstract]
Deposits	Deposits The following is a summary of scheduled maturities of CDs as of December 31, 2017 : Retail Brokered Total 2018 $ 239,936 $ — $ 239,936 2019 110,867 — 110,867 2020 62,944 7,000 69,944 2021 32,208 — 32,208 2022 19,816 — 19,816 Thereafter 9,239 — 9,239 Total $ 475,010 $ 7,000 $ 482,010 CDs issued in amounts that meet or exceed the FDIC insurance limit of $250,000 totaled $137.1 million and $104.5 million at December 31, 2017 and 2016 , respectively. At December 31, 2017 and 2016 , the Company, in the normal course of business, had deposits from certain officers, directors, and their associated companies totaling $14.9 million and $14.4 million , respectively. The Company has pledged assets as collateral covering certain deposits in the amount of $434.6 million and $377.9 million at December 31, 2017 and 2016, respectively. The amount of overdraft deposits that were reclassified as loans at December 31, 2017 and 2016 was $897,000 and $986,000 , respectively.

Borrowings

Borrowings	12 Months Ended
	Dec. 31, 2017
Debt Disclosure [Abstract]
Borrowings	Borrowings The following table summarizes the Company's short term and long term borrowings, and subordinated debentures as presented on the consolidated statements of condition for the periods indicated: December 31, 2017 Contractual Maturity December 31, 2016 Outstanding Balance Weighted Average Rate 2018 2019 2020 2021 2022 Thereafter Outstanding Balance Weighted Average Rate Short-Term Borrowings: FHLBB borrowings $ 250,000 $ 250,000 $ — $ — $ — $ — $ — $ 210,000 Customer repurchase agreements 244,646 244,646 — — — — — 225,605 FHLBB and correspondent bank overnight borrowings 47,150 47,150 — — — — — 89,450 Wholesale repurchase agreements — — — — — — — 5,007 Capital lease obligation 71 71 — — — — — 67 Total short-term borrowings $ 541,867 1.10 % $ 541,867 $ — $ — $ — $ — $ — $ 530,129 0.74 % Long-Term Borrowings: FHLBB borrowings $ 10,000 1.87 % $ — $ — $ 10,000 $ — $ — $ — $ 10,000 1.87 % Capital lease obligation 720 4.18 % — 76 81 90 98 375 791 4.31 % Total long-term borrowings $ 10,720 2.03 % $ — $ 76 $ 10,081 $ 90 $ 98 $ 375 $ 10,791 2.05 % Subordinated Debentures: Subordinated debentures (1) $ 14,580 5.50 % $ — $ — $ — $ — $ — $ 14,580 $ 14,526 5.50 % CCTA 36,083 5.48 % — — — — — 36,083 36,083 5.50 % UBCT 8,248 6.75 % — — — — — 8,248 8,146 6.85 % Total subordinated debentures $ 58,911 5.66 % $ — $ — $ — $ — $ — $ 58,911 $ 58,755 5.69 % (1) Presented net of debt issuance costs of $420,000 and $474,000 at December 31, 2017 and 2016, respectively. Short-Term Borrowings Short-term borrowings consist of customer repurchase agreements, FHLBB advances due in less than 90 days, FHLBB and correspondent bank overnight borrowings, and other short-term borrowings due within one year. The Bank had an available line of credit with the FHLBB of $9.9 million at December 31, 2017 and 2016 . This line of credit serves as overdraft protection should the Company overdraw its account with the FHLBB. The interest rate for this line of credit is set daily by the FHLBB. The Company had no outstanding balance on the line of credit with the FHLBB at December 31, 2017 or 2016 . Long-Term Borrowings Long-term borrowings represent securities sold under repurchase agreements with major brokerage firms and notes payable with maturity dates over one year. Both wholesale and retail repurchase agreements are secured by mortgage-backed securities and securities of government sponsored enterprises. At December 31, 2017, the Company has the following lines of credit available to it, for which it had no outstanding balances: • The Company has an unsecured $10.0 million line of credit with PNC Bank that has a maturity date of December 20, 2018 for which the interest rate is LIBOR-based and is set daily by PNC Bank. • The Company, through the Bank, has an unsecured $50.0 million line of credit with PNC Bank for which the interest rate is set daily by PNC Bank. • The Company, through the Bank, has a secured line of credit of $99.8 million through the FRB's Discount Window for which the interest rate is set by the FRB daily. At December 31, 2017 , the Bank pledged commercial loans with a carrying value of $144.4 million and investment securities of $31,000 . FHLBB Borrowings At December 31, 2017, the terms of the Company's outstanding FHLBB borrowings were as follows: Balance Sheet Classification Outstanding Balance Maturity Date Interest Rate Range Next Call Date Call Amount Short-Term Borrowings $ 200,000 January 2018 1.45% - 1.63% N/A $ — Short-Term Borrowings $ 50,000 February 2018 1.54% N/A $ — Long-Term Borrowings $ 10,000 April 2020 1.87% N/A $ — FHLBB borrowings are collateralized by a blanket lien on qualified collateral consisting primarily of loans with first mortgages secured by one- to four-family properties, certain commercial real estate loans, certain pledged investment securities and other qualified assets. The carrying value of residential real estate and commercial loans pledged as collateral was $1.1 billion at December 31, 2017 and 2016 . The carrying value of securities pledged as collateral at the FHLBB was $215,000 and $400,000 at December 31, 2017 and 2016 , respectively. Subordinated Debentures The Company issued $15.0 million of subordinated debt on October 8, 2015, which qualifies as Tier II regulatory capital. The interest rate on the subordinated debt is 5.50% per annum, fixed for the ten -year term and payable semi-annually on April 15 and October 15 each year. The Company can redeem the subordinated debt at par starting on October 15, 2020 plus accrued and unpaid interest, or earlier if (i) they no longer qualify as Tier II capital for regulatory capital purposes; (ii) a change in law that prevents the Company from deducting interest payable for U.S. federal income tax purposes, or (iii) the Company is required to register as an investment company pursuant to the Investment Company Act of 1940. The subordinated debt is schedule to mature on October 15, 2025 . The Company incurred issuance costs of $536,000 associated with this debt issuance. The Company capitalized these costs and they have been presented within subordinated debentures on the consolidated statements of condition. The Company will amortize the issuance costs over the ten -year term of the subordinated debt. The amortization costs incurred for the year ended December 31, 2017 and 2016 associated with the debt issuance was $54,000 , and was recognized as an increase to interest expense within the consolidated statements of income. In April 2006, the Company formed CCTA, which issued and sold trust preferred securities to the public. The Company received $36.1 million from the issuance of the trust preferred securities in return for junior subordinated debentures issued by the Company to CCTA. The Company owns all of the $1.1 million of outstanding common securities of CCTA. The interest rate of the trust preferred securities was fixed at 6.71% through June 2011 and now floats at the 3 month LIBOR plus 140 basis points . The proceeds from the offering were used to repurchase Company common stock under the tender offer completed in May 2006. The trust preferred securities, which pay interest quarterly at the same rate as the junior subordinated debentures held by CCTA, are mandatorily redeemable on June 30, 2036, or may be redeemed by CCTA at par any time on or after June 30, 2011. In connection with the acquisition of Union Bankshares Company in 2008, the Company assumed $8.0 million of trust preferred securities, held through a Delaware trust affiliate, UBCT. In 2006, Union Bankshares Company issued an aggregate principal amount of $8.2 million of 30 -year junior subordinated deferrable interest debt securities to UBCT. The Company owns all of the $248,000 of outstanding common securities of UBCT. The debt securities obligate the Company to pay interest on their principal sum quarterly in arrears on January 7, April 7, July 7, and October 7 of each year. The interest rate of the trust preferred securities until April 7, 2011 was a blended rate equal to the sum of (1) the product of 50% times the average three-month LIBOR plus 1.42%, plus (2) the product of 50% times 6.4725%. The rate is now the average three-month LIBOR plus 1.42%. The debt securities mature on April 7, 2036, but may be redeemed by the Company, in whole or in part, beginning on April 7, 2011, on any interest payment date. The debt securities may also be redeemed by the Company in whole or in part, within 90 days of the occurrence of certain special redemption events as defined in the Indenture. CCTA and UBCT are Delaware statutory trusts created for the sole purpose of issuing trust preferred securities and investing the proceeds in junior subordinated debentures of the Company. The junior subordinated debentures are the sole assets of the trusts. The Company is the owner of all of the common securities of CCTA and UBCT and fully and unconditionally guarantees each trust’s securities obligations. In accordance with GAAP, CCTA and UBCT are treated as unconsolidated subsidiaries. The common stock investment in the statutory trusts is included in other assets on the consolidated statements of condition. At December 31, 2017 , $43.0 million of the trust preferred securities were included in the Company’s total Tier I capital and amounted to 12.0% of Tier I capital of the Company. The Company has a notional amount of $43.0 million in interest rate swap agreements on its junior subordinated debentures. Further discussion on the terms and accounting for the interest rate swap agreements is included within Note 18 of the consolidated financial statements. Interest expense on the subordinated debentures, including the effective portion of the associated interest rate swaps on these debt instruments reclassified from OCI into earnings, totaled $3.4 million , $3.4 million and $2.7 million for the year ended December 31, 2017 , 2016 and 2015 , respectively. Refer to Note 18 of the consolidated financial statements for information pertaining to the reclassification of OCI into earnings on the interest rate swaps.

Repurchase Agreements

Repurchase Agreements	12 Months Ended
	Dec. 31, 2017
Banking and Thrift [Abstract]
Repurchase Agreements	Repurchase Agreements The Company can raise additional liquidity by entering into repurchase agreements at its discretion. In a security repurchase agreement transaction, the Company will generally sell a security, agreeing to repurchase either the same or substantially identical security on a specified later date, at a greater price than the original sales price. The difference between the sale price and purchase price is the cost of the proceeds, which is recorded as interest expense on the consolidated statement of income. The securities underlying the agreements are delivered to counterparties as security for the repurchase obligations. Since the securities are treated as collateral and the agreement does not qualify for a full transfer of effective control, the transactions does not meet the criteria to be classified as a sale, and is therefore considered a secured borrowing transaction for accounting purposes. Payments on such borrowings are interest only until the scheduled repurchase date. In a repurchase agreement the Company is subject to the risk that the purchaser may default at maturity and not return the securities underlying the agreements. In order to minimize this potential risk, the Company either deals with established firms when entering into these transactions or with customers whose agreements stipulate that the securities underlying the agreement are not delivered to the customer and instead are held in segregated safekeeping accounts by the Company's safekeeping agents. The tables below sets forth information regarding the Company’s repurchase agreements accounted for as secured borrowings and types of collateral at December 31, 2017 and 2016 : Remaining Contractual Maturity of the Agreements Overnight and Continuous Up to 30 Days 30 - 90 Days Greater than 90 Days Total December 31, 2017 Customer Repurchase Agreements: Obligations of states and political subdivisions $ 630 $ — $ — $ — $ 630 Mortgage-backed securities issued or guaranteed by U.S. government-sponsored enterprises 98,460 — — — 98,460 Collateralized mortgage obligations issued or guaranteed by U.S. government-sponsored enterprises 145,556 — — — 145,556 Total Customer Repurchase Agreements 244,646 — — — 244,646 Total Repurchase Agreements (1) $ 244,646 $ — $ — $ — $ 244,646 December 31, 2016 Customer Repurchase Agreements: Mortgage-backed securities issued or guaranteed by U.S. government-sponsored enterprises $ 117,784 $ — $ — $ — $ 117,784 Collateralized mortgage obligations issued or guaranteed by U.S. government-sponsored enterprises 107,821 — — — 107,821 Total Customer Repurchase Agreements 225,605 — — — 225,605 Wholesale Repurchase Agreements: Mortgage-backed securities issued or guaranteed by U.S. government-sponsored enterprises — — 3,715 — 3,715 Collateralized mortgage obligations issued or guaranteed by U.S. government-sponsored enterprises — — 1,292 — 1,292 Total Wholesale Repurchase Agreements — — 5,007 — 5,007 Total Repurchase Agreements (1) $ 225,605 $ — $ 5,007 $ — $ 230,612 (1) Presented within short-term borrowings on the consolidated statements of condition. Certain customers held CDs totaling $920,000 and $917,000 with the Bank at December 31, 2017 and 2016 , respectively, that were collateralized by CMO and MBS securities that were overnight repurchase agreements. Certain counterparties monitor collateral, and may request additional collateral to be posted from time to time.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes The current and deferred components of income tax expense on the consolidated statements of income were as follows: For The Year Ended December 31, 2017 2016 2015 Current: Federal $ 14,529 $ 17,854 $ 7,956 State 1,289 930 71 15,818 18,784 8,027 Deferred: Change in federal corporate income tax rate (1) 14,263 — — Federal 4,117 (1,258 ) 1,356 State (320 ) (54 ) 524 18,060 (1,312 ) 1,880 Income tax expense $ 33,878 $ 17,472 $ 9,907 (1) On December 22, 2017, the Tax Act was enacted, reducing the U.S. federal corporate income tax rate from 35.0% to 21.0%. ASC Topic 740, Accounting for Income Taxes (“ASC 740”), requires companies to recognize the effect of tax law changes in the period of enactment even though the effective date for most provisions of the Tax Act was January 1, 2018. As of December 31, 2017, the Company has completed its accounting for the tax effects of the Tax Act, which resulted in a reduction to net deferred tax assets and a corresponding charge to income tax expense of $14.3 million. The income tax expense differs from the amount computed by applying the statutory federal income tax rate as a result of the following: For The Year Ended December 31, 2017 2016 2015 Computed tax expense $ 21,824 $ 20,139 $ 10,801 Increase (reduction) in income taxes resulting from: Change in federal corporate income tax rate 14,263 — — Tax exempt income (1,291 ) (1,312 ) (1,092 ) Income from life insurance (829 ) (908 ) (588 ) State taxes, net of federal benefit 630 565 373 Share-based awards (1) (390 ) (701 ) — Low income housing credits (366 ) (376 ) (359 ) Non-deductible acquisition-related costs — — 467 Other 37 65 305 Income tax expense $ 33,878 $ 17,472 $ 9,907 Income before income taxes $ 62,354 $ 57,539 $ 30,859 Effective tax rate 54.3 % 30.4 % 32.1 % (1) The Company adopted the provisions of ASU 2016-09, Compensation—Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting , in calendar year 2016. Prior to adoption, it accounted for its windfall tax benefits or shortfalls generated upon exercise of a non-qualified stock option or a disqualifying incentive stock option, or upon vesting of its restricted shares through shareholders' equity (or as income tax expense to the extent the Company did not have a windfall tax benefit surplus). Upon adoption, the Company now accounts for its windfall tax benefits and shortfalls generated within income tax expense on the consolidated statements of income as a discrete period item in the quarter generated. Temporary differences between the financial statements carrying amounts and the tax bases of assets and liabilities gave rise to the following deferred tax assets and liabilities: December 31, 2017 (1) 2016 (2) Asset Liability Asset Liability Net operating loss and tax credit carryforward $ 12,078 $ — $ 20,977 $ — Allowance for loan losses 5,201 — 8,094 — Pension and other benefits 3,363 — 5,141 — Net unrealized losses on AFS securities 2,821 — 3,227 — Net unrealized losses on derivative instruments 1,623 — 3,066 — Deferred compensation and benefits 1,199 — 1,791 — Net unrealized losses on postretirement plans 1,092 — 1,147 — Purchase accounting and deposit premium 461 — 1,430 — Depreciation — (2,857 ) — (4,520 ) Deferred loan origination fees — (1,510 ) — (2,046 ) Other — (695 ) 956 — 27,838 (5,062 ) 45,829 (6,566 ) Valuation allowance on deferred tax assets — — Net deferred tax assets $ 22,776 $ 39,263 (1) At December 31, 2017, the Company's deferred tax assets and liabilities were calculated using a 21.5% deferred tax rate. (2) At December 31, 2016, the Company's deferred tax assets and liabilities were calculated using a 35.0% deferred tax rate. In connection with the acquisition of SBM on October 16, 2016, the Company acquired certain net operating losses and tax credit carryforwards as of the acquisition date, including federal net operating losses of $71.2 million and State of Maine net operating losses of $213,000 . The Company determined it would not be able to utilize $6.8 million of the acquired federal net operating losses and wrote-off this amount within purchase accounting. Due to Internal Revenue Code of 1986, as amended, Section 382(g) limitations, the Company's use of the federal net operating losses acquired is limited to $3.9 million annually (and $803,000 for fiscal year 2015), which was determined using the applicable federal rate and the fair value of consideration paid for the acquisition at the acquisition date. The acquired federal net operating losses will expire between 2030 and 2034 . The Company has assessed the need for a valuation allowance on the acquired federal net operating losses and determined that there was a high likelihood that it will be able to utilize all of the acquired allowable federal net operating losses prior to expiration as the Company has a history of generating taxable income well in excess of the limitation. As such, no valuation allowance has been established on its acquired federal net operating losses or tax credit carryforwards as of December 31, 2017 or 2016. As of December 31, 2017, the Company's federal income tax returns for the year ended December 31, 2016 and 2015 were open to audit by federal authorities and state income tax returns for the year ended December 31, 2016, 2015 and 2014 were open to audit by state authorities. During the year ended December 31, 2017, the IRS completed its examination of the Company's 2013 and 2014 federal income tax returns, which resulted in no material changes to the Company's consolidated financial statements.

Shareholders' Equity

Shareholders' Equity	12 Months Ended
	Dec. 31, 2017
Stockholders' Equity Note [Abstract]
Shareholders' Equity	Shareholders’ Equity Regulatory Capital Requirements The Company and Bank are subject to various regulatory capital requirements administered by the FRB and the OCC. Failure to meet minimum capital requirements can result in mandatory and possible additional discretionary actions by regulators that, if undertaken, could have a direct material effect on the Company’s consolidated financial statements. The Company and the Bank are required to maintain certain levels of capital based on risk-adjusted assets. These capital requirements represent quantitative measures of their assets, liabilities and certain off-balance sheet items as calculated under regulatory accounting practices. The Company and the Bank's capital classification is also subject to qualitative judgments by our regulators about components, risk weightings and other factors. The quantitative measures established to ensure capital adequacy require us to maintain minimum amounts and ratios of total, Tier I capital, and common equity Tier I to risk-weighted assets, and of Tier I capital to average assets, or leverage ratio. These guidelines apply to the Company on a consolidated basis. Under the current guidelines, banking organizations must have a minimum total risk-based capital ratio of 8.0% , a minimum Tier I risk-based capital ratio of 6.0% , a minimum common equity Tier I risk-based capital ratio of 4.5% , and a minimum leverage ratio of 4.0% in order to be "adequately capitalized." In addition to these requirements, banking organizations must maintain a 2.5% capital conservation buffer consisting of common Tier I equity, subject to a transition schedule with a full phase-in by 2019. Effective January 1, 2017, the Company and the Bank were required to establish a capital conservation buffer of 1.25% , increasing the minimum required total risk-based capital, Tier I risk-based and common equity Tier I capital to risk-weighted assets they must maintain to avoid limits on capital distributions and certain bonus payments to executive officers and similar employees. The Company and Bank's risk-based capital ratios exceeded regulatory guidelines at December 31, 2017 and 2016, and, specifically, the Bank was "well capitalized" under prompt correct action provisions for each period. There were no conditions or events that occurred subsequent to December 31, 2017 that would change the Company or Bank's regulatory capital categorization. The following table presents the Company and Bank's regulatory capital ratios at the periods indicated: December 31, Minimum Regulatory Capital Required for Capital Adequacy plus Capital Conservation Buffer Minimum Regulatory Provision To Be "Well Capitalized" Under Prompt Corrective Action Provisions December 31, Minimum Regulatory Capital Required For Capital Adequacy plus Capital Conservation Buffer Minimum Regulatory Provision To Be "Well Capitalized" Under Prompt Corrective Action Provisions Amount Ratio Amount Ratio Camden National Corporation: Total risk-based capital ratio $ 396,451 14.14 % 9.25 % N/A $ 368,856 14.04 % 8.63 % N/A Tier I risk-based capital ratio 357,261 12.74 % 7.25 % N/A 330,729 12.59 % 6.63 % N/A Common equity Tier I risk-based capital ratio 316,677 11.30 % 5.75 % N/A 296,120 11.27 % 5.13 % N/A Tier I leverage capital ratio 357,261 9.07 % 4.00 % N/A 330,729 8.83 % 4.00 % N/A Camden National Bank: Total risk-based capital ratio $ 369,540 13.18 % 9.25 % 10.00 % $ 340,908 12.92 % 8.63 % 10.00 % Tier I risk-based capital ratio 345,350 12.32 % 7.25 % 8.00 % 317,782 12.05 % 6.63 % 8.00 % Common equity Tier I risk-based capital ratio 345,350 12.32 % 5.75 % 6.50 % 317,782 12.05 % 5.13 % 6.50 % Tier I leverage capital ratio 345,350 8.80 % 4.00 % 5.00 % 317,782 8.54 % 4.00 % 5.00 % On October 8, 2015, the Company issued $15.0 million of 10 year subordinated debentures bearing interest at an annual rate of 5.50% . In addition, $43.0 million of junior subordinated debentures were issued in connection with the issuance of trust preferred securities in 2006 and 2008. Although the subordinated debentures and the junior subordinated debentures are recorded as liabilities on the Company's consolidated statements of condition, the Company is permitted, in accordance with regulatory guidelines, to include, subject to certain limits, each within its calculation of risk-based capital. At December 31, 2017 and 2016, $15.0 million of subordinated debentures were included as Tier II capital and were included in the calculation of the Company's total risk-based capital, and, at December 31, 2017 and December 31, 2016, $43.0 million of the junior subordinated debentures were included in Tier I and total risk-based capital for the Company. The Company and Bank's regulatory capital and risk-weighted assets fluctuate due to normal business, including profits and losses generated by the Company and Bank as well as changes to their asset mix. Of particular significance are changes within the Company and Bank's loan portfolio mix due to the difference in regulatory risk-weighting differences between retail and commercial loans. Furthermore, the Company and Bank's regulatory capital and risk-weighted assets are subject to change due to changes in GAAP and regulatory capital standards. The Company and Bank proactively monitor their regulatory capital and risk-weighted assets, and the impact of changes to their asset mix, and impact of proposed and pending changes as a result of new and/or amended GAAP standards and regulatory changes. Dividends The primary source of funds available to the Company for the payment of dividends to its shareholders is dividends paid to the Company by its subsidiary, the Bank. The Bank is subject to certain requirements imposed by federal banking laws and regulations. These requirements, among other things, establish minimum levels of capital and restrict the amount of dividends that a bank subsidiary may distribute. Under regulations prescribed by the OCC, without prior OCC approval, a bank subsidiary may not declare dividends in any year in excess of the bank’s (i) net income for the current year, (ii) plus its retained net income for the prior two years. For the year ended December 31, 2017 , 2016 , and 2015, the Bank declared dividends for payment to the Company in the amount of $16.8 million , $16.0 million , and $39.2 million which included a $30.0 million special dividend that was paid in connection with the acquisition of SBM, respectively. For the year ended December 31, 2017, 2016 and 2015, the Company declared $14.6 million , $12.9 million and $10.6 million , respectively, in dividends payable to its shareholders. Common Stock Split On August 30, 2016, the Company's Board of Directors declared a three-for-two stock split, effected in the form of a stock dividend, on the Company's common stock. Each shareholder of record on September 15, 2016, received one additional share of common stock for every two shares of common stock owned. The stock was issued September 30, 2016. The Company paid shareholders cash in lieu of fractional shares of common stock in connection with the split, at a price of $31.75 per share, the closing price of the Company’s common stock on September 14, 2016. The total cash paid for fractional shares was $5,000 , and was accounted for as a reduction of capital stock. Common Stock Repurchase On September 24, 2013, the Company's Board of Directors authorized the 2013 Repurchase Plan. The 2013 Repurchase Plan allows for the repurchase of up to 375,000 shares of the Company’s outstanding common stock. This program is expected to continue until the authorized number of shares is repurchased, or the Company’s Board of Directors terminates the program. As of December 31, 2017 , the Company had repurchased 374,250 shares at a weighted-average price of $ 26.55 , or 99.8% of the program’s total allotment. The Company did no t repurchase any of its outstanding common stock for the year ended December 31, 2017 .

Earnings per Share

Earnings per Share	12 Months Ended
	Dec. 31, 2017
Earnings Per Share [Abstract]
Earnings per Share	EPS The following is an analysis of basic and diluted EPS, reflecting the application of the two-class method, as described below: For The Year Ended December 31, 2017 2016 2015 Net income $ 28,476 $ 40,067 $ 20,952 Dividends and undistributed earnings allocated to participating securities (1) (118 ) (189 ) (59 ) Net income available to common shareholders $ 28,358 $ 39,878 $ 20,893 Weighted-average common shares outstanding for basic EPS 15,509,665 15,422,160 12,031,294 Dilutive effect of stock-based awards (2) 78,682 82,079 43,285 Weighted-average common and potential common shares for diluted EPS 15,588,347 15,504,239 12,074,579 Earnings per common share: Basic EPS $ 1.83 $ 2.59 $ 1.73 Diluted EPS $ 1.82 $ 2.57 $ 1.73 Awards excluded from the calculation of diluted EPS (3) : Stock options — — 19,875 (1) Represents dividends paid and undistributed earnings allocated to nonvested stock-based awards that contain non-forfeitable rights to dividends. (2) Represents the effect of the assumed exercise of stock options, and vesting of restricted shares and restricted stock units, and issuance of LTIP awards that have met the performance criteria, utilizing the treasury stock method. (3) Represents stock-based awards not included in the computation of potential common shares for purposes of calculating diluted EPS as the exercise prices were greater than the average market price of the Company's common stock, and, therefore, are considered anti-dilutive. Nonvested stock-based payment awards that contain non-forfeitable rights to dividends are participating securities and are included in the computation of EPS pursuant to the two-class method. The two-class method is an earnings allocation formula that determines EPS for each class of common stock and participating security according to dividends declared (or accumulated) and participation rights in undistributed earnings. Certain of the Company’s nonvested stock-based awards qualify as participating securities. Net income is allocated between the common stock and participating securities pursuant to the two-class method. Basic EPS is computed by dividing net income available to common shareholders by the weighted average number of common shares outstanding during the period, excluding participating nonvested stock-based awards. Diluted EPS is computed in a similar manner, except that the denominator includes the number of additional common shares that would have been outstanding if potentially dilutive common shares were issued using the treasury stock method.

Stock-Based Compensation Plans

Stock-Based Compensation Plans	12 Months Ended
	Dec. 31, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock-Based Compensation Plans	Stock-Based Compensation Plans Stock-Based Compensation On April 29, 2003 and May 1, 2012, the shareholders of the Company approved the 2003 Plan and 2012 Plan, respectively. The maximum number of shares of stock reserved and available for issuance under each the 2003 Plan and 2012 Plan is 1.2 million shares. As shares or units are vested or options are exercised, new shares are issued out of either the 2003 or 2012 Plan. Awards may be granted in the form of incentive stock options, non-qualified stock options, stock appreciation rights, restricted stock, restricted stock units, unrestricted stock, performance shares and dividend equivalent rights, or any combination of the preceding, and the exercise price shall not be less than 100% of the fair market value on the date of grant in the case of incentive stock options, or 85% of the fair market value on the date of grant in the case of non-qualified stock options. No stock option is exercisable more than ten years after the date the stock option is granted. The exercise price of all options granted equaled the market price of the Company's stock on the date of grant, except for the non-qualified stock options issued in conjunction with the acquisition of SBM. Refer to Note 2 for additional details. The amount of cash used to settle stock-based compensation transactions for the year ended December 31, 2017, 2016 and 2015 was $902,000 , $373,000 and $157,000 , respectively. Stock Option Awards Stock options granted under the 2003 Plan and the 2012 Plan have been both incentive stock options and non-qualified stock options. All incentive stock options and non-qualified stock options granted vest pro rata over a five year period and have a contractual life of ten years. On the date of each grant, the fair value of each award is derived using the Black-Scholes option pricing model based on assumptions made by the Company as follows: • Dividend yield is based on the dividend rate of the Company’s stock at the date of grant. • Risk-free interest rate is based on the U.S. Treasury bond rate with a term equaling the expected life of the granted options. • Expected volatility is based on the historical volatility of the Company’s stock price calculated over the expected life of the option. • Expected life represents the period of time that granted options are expected to be outstanding based on historical trends. For the year ended December 31, 2017, 2016 and 2015, the Company issued stock options with a grant-date fair value of $0 , $16,000 and $22,000 , respectively. The following table presents the option pricing assumptions and the estimated fair value of the options using these assumptions for grants made for the year ended: December 31, 2017 2016 2015 Weighted-average dividend yield — % 3.12 % 3.01 % Weighted-average risk-free interest rate — % 1.52 % 1.50 % Weighted-average expected volatility — % 29.64 % 31.85 % Weighted-average expected life (in years) 0.0 5.3 5.3 Weighted-average fair value of options granted $ — $ 5.17 $ 5.87 Compensation expense is recognized on a straight-line basis over the option vesting period. For the year ended December 31, 2017, 2016 and 2015, the compensation expense recognized for stock options was $20,000 , $30,000 and $51,000 , respectively. The Company does not receive any tax benefit on its issuance of incentive stock options, unless upon exercise a disqualifying disposition is made. The total tax benefit to the Company upon exercise of incentive stock options for the year ended December 31, 2017 , 2016 and 2015 was $21,000 , $36,000 , and $59,000 , respectively. Additionally, for the year ended December 31, 2017, 2016 and 2015, the Company received a tax benefit upon the exercise of non-qualified stock options that were issued as consideration in the acquisition of SBM, of $21,000 , $378,000 and $0 , respectively. Unrecognized compensation expense for nonvested stock options totaled $41,000 at December 31, 2017 and is expected to be recognized over the remaining weighted-average vesting period of 2.3 years. The total intrinsic value of options exercised for the year ended December 31, 2017 , 2016 and 2015 was $268,000 , $2.5 million, and $573,000 , respectively. Stock option activity for the year ended December 31, 2017 was as follows: Number of Options Weighted-Average Exercise Price per Option Weighted-Average Remaining Contractual Term (Years) Aggregate Intrinsic Value Options outstanding at January 1, 2017 58,743 $ 20.38 Granted — — Exercised (11,841 ) 17.50 Forfeited (2,400 ) 26.23 Expired (1,425 ) 23.11 Options outstanding at December 31, 2017 43,077 $ 21.00 3.45 $ 910 Options exercisable at December 31, 2017 39,627 $ 20.58 3.11 $ 854 A summary of the status of the Company’s nonvested stock options as of December 31, 2017 and changes during the year then ended was as follows: Options Weighted-Average Grant Date Fair Value per Option Nonvested at January 1, 2017 9,450 $ 6.59 Granted — — Vested (3,600 ) 7.80 Forfeited (2,400 ) 5.48 Nonvested at December 31, 2017 3,450 $ 6.11 For the year ended December 31, 2017 , 2016 and 2015 the Company received cash from the exercise of stock options of $98,000 , $1.3 million and $736,000 respectively. Restricted Stock Units For the year ended December 31, 2017, 2016 and 2015, the Company issued restricted stock units with a grant-date fair value of $808,000 , $0 and $0 , respectively, to certain employees. The grant-date fair value is calculated utilizing the Company's closing market share price as of the date the awards are granted. Restricted stock units vest pro-rata over the requisite service period, which is typically three to five years, and may contain certain performance-based conditions. Restricted stock units issued do not participate in dividends and recipients are not entitled to vote these restricted units until they vest. Compensation expense and the related income tax benefit recognized in connection with the restricted stock units was as follows for the periods indicated: For The Year Ended 2017 2016 2015 Compensation expense $ 124 $ — $ — Income tax benefit 27 — — Fair value of grants vested — — — Restricted stock unit activity for the year ended December 31, 2017 was as follows: Number of Units Weighted-Average Grant Date Fair Value per Unit Weighted-Average Remaining Contractual Term (Years) Aggregate Intrinsic Value Unrecognized Compensation Nonvested at January 1, 2017 — $ — Granted 18,762 43.05 Vested — — Forfeited (1,285 ) 43.11 Nonvested at December 31, 2017 17,477 $ 43.04 4.6 $ 736 $ 620 Restricted Stock Awards For the year ended December 31, 2017, 2016 and 2015, the Company issued restricted stock awards with a grant-date fair value of $686,000 , $925,000 and $1.0 million , respectively, to certain directors and employees. The grant-date fair value is calculated utilizing the Company's closing market share price as of the date the awards are granted. Restricted stock awards vest pro-rata over the requisite service period, which is typically three to five years, with the exception of awards issued to Company directors that typically vest immediately, and may contain certain performance-based conditions. Nonvested restricted stock awards participate in dividends and recipients are entitled to vote these restricted shares during the vesting period. Compensation expense and the related income tax benefit recognized in connection with the restricted stock awards was as follows for the periods indicated: For The Year Ended 2017 2016 2015 Compensation expense $ 762 $ 703 $ 327 Income tax benefit 164 246 114 Fair value of grants vested 702 603 341 Restricted stock award activity for the year ended December 31, 2017 is as follows: Number of Shares Weighted-Average Grant Date Fair Value per Share Weighted-Average Remaining Contractual Term (Years) Aggregate Intrinsic Value Unrecognized Compensation Nonvested at January 1, 2017 47,518 $ 28.16 Granted 16,185 42.39 Vested (22,553 ) 31.14 Forfeited (4,825 ) 28.93 Nonvested at December 31, 2017 36,325 $ 32.56 2.2 $ 1,530 $ 787 MSPP For the year ended December 31, 2017, 2016 and 2015, the Company issued MSPP awards with a grant-date fair value of $111,000 , $128,000 and $108,000 , respectively, to certain employees. The Company offers the MSPP to provide an opportunity for certain employees to receive restricted shares of the Company’s common stock in lieu of their annual incentive bonus. Restricted shares issued under the MSPP are granted at a discount of one-third of the fair market value of the stock on the date of grant and cliff vests two years after the grant date. Should an employee forfeit his or her nonvested MSPP awards, the Company will return the lesser of the strike price paid by the employee or the fair value of the nonvested awards as of the date forfeited. Restricted stock issued under the MSPP to certain employees participate in dividends and are entitled to vote these restricted shares during the vesting period. Compensation expense and the related income tax benefit recognized in connection with the MSPP awards was as follows for the periods indicated: For The Year Ended 2017 2016 2015 Compensation expense $ 97 $ 102 $ 66 Income tax benefit 21 36 23 Fair value of grants vested 91 57 92 MSPP award activity for the year ended December 31, 2017 was as follows: Number of Shares Weighted-Average Grant Date Fair Value per Share Weighted-Average Remaining Contractual Term (Years) Aggregate Intrinsic Value Unrecognized Compensation Nonvested at January 1, 2017 26,699 $ 7.85 Granted 8,088 13.73 Vested (11,777 ) 7.73 Forfeited (2,791 ) 11.49 Nonvested at December 31, 2017 20,219 $ 9.77 1.0 $ 431 $ 54 For the year ended December 31, 2017 , 2016 and 2015 the Company received cash from the issuance of restricted shares under the MSPP of $180,000 , $241,000 and $220,000 respectively. At December 31, 2017 and 2016, $421,000 and $454,000 of the MSPP cash received was included in accrued interest and other liabilities in the consolidated statements of condition. LTIP The LTIP is intended to attract and retain executives who will contribute to the Company’s future success. The long-term performance period is a period of three consecutive years beginning on January 1 of the first year and ending on December 31 of the third year. Awards are based upon either: (i) the attainment of certain performance targets on specific performance measures selected by the Compensation Committee and approved by the Board of Directors; or (ii) 50% weighted on the attainment of certain performance targets on specific performance measures selected by the Compensation Committee and approved by the Board of Directors and 50% weighted on meeting the requisite service period. The performance-based share units granted will vest only if specific performance measures, as defined under the LTIP, are achieved. Failure to achieve the specific performance measures will result in all or a portion of the shares being forfeited. The service-based share units granted vest annually pro-rata over the three year period. For the year ended December 31, 2017, 2016 and 2015, the Company issued restricted stock awards as part of the LTIP to certain executives with a grant-date fair value of $697,000 , $502,000 and $0 , respectively. For the year ended December 31, 2017, 2016 and 2015, the Company issued performance-based stock awards with a grant-date fair value of $697,000 , $502,000 and $963,000 , respectively. The grant-date fair value is calculated utilizing the Company's closing market share price as of the date the awards are granted. Compensation expense recognized for the LTIP's restricted stock awards was presented within " —Restricted Stock Awards " above. Compensation expense for the LTIP's performance-based awards was presented in the following table: For The Year Ended 2017 2016 2015 Compensation expense (1) $ 370 $ 1,080 $ 330 Related income tax benefit 80 378 116 Fair value of grants vested 843 725 412 LTIP restricted stock award activity for the year ended December 31, 207 was presented within " —Restricted Stock Awards " above. LTIP performance-based award activity for the year ended December 31, 2017 was as follows: Number of Shares Weighted-Average Grant Date Fair Value per Share Weighted-Average Remaining Contractual Term (Years) Aggregate Intrinsic Value Unrecognized Compensation Nonvested at January 1, 2017 52,737 $ 27.01 Granted 16,830 41.39 Vested (32,323 ) 26.09 Forfeited (5,621 ) 26.97 Nonvested at December 31, 2017 31,623 $ 35.60 1.7 $ 1,332 $ 291 DCRP The DCRP is an unfunded deferred compensation plan for the benefit of certain Company executives. The Company’s Compensation Committee determines eligibility in the DCRP and annually, participants will receive a credit to an account administered by the Company of 10% of each participant’s annual base salary and bonus for the prior performance period. Annual credits to a participant’s account will be denominated in deferred stock awards (the right to receive a share of common stock of the Company upon the satisfaction of certain restrictions) based on the fair market value of the common stock of the Company on the date of grant. Vesting occurs ratably from the date of participation until the participant reaches the age of 65, at which time the participant is 100% vested. Subsequent to December 31, 2017, the DCRP was amended providing the ability to tailor vesting terms for new participants. Upon retirement or termination of employment, the participant will receive shares of common stock equal to the Deferred Stock Awards in the account multiplied by the vested percentage, reduced by the amount to be withheld for income taxes; unvested awards will be forfeited. For the year ended December 31, 2017, 2016 and 2015, the Company issued DCRP awards with a grant-date fair value of $118,000 , $111,000 and $93,000 , respectively. The grant-date fair value is calculated utilizing the Company's closing market share price as of the date the awards are granted. Compensation expense recognized in connection with the DCRP was presented in the following table: For The Year Ended 2017 2016 2015 Compensation expense $ 97 $ 81 $ 62 Related income tax benefit 21 28 22 Fair value of grants vested 90 75 59 DCRP award activity for the year ended December 31, 2017 was as follows: Number of Deferred Stock Awards Weighted-Average Grant Date Fair Value per Award Weighted-Average Remaining Contractual Term (Years) Aggregate Intrinsic Value Unrecognized Compensation Nonvested at January 1, 2017 14,244 $ 23.65 Granted 2,772 42.66 Vested (2,776 ) 32.50 Forfeited (4,192 ) 25.88 Nonvested at December 31, 2017 10,048 $ 25.52 9.2 $ 423 $ 229

Employee Benefit Plans

Employee Benefit Plans	12 Months Ended
	Dec. 31, 2017
Compensation and Retirement Disclosure [Abstract]
Employee Benefit Plans	Employee Benefit Plans 401(k)/Profit Sharing Plan The Company has a 401(k)/profit sharing plan and the majority of employees participate in the plan. Employees may contribute pre-tax contributions to the 401(k)/profit sharing plan up to the maximum amount allowed by federal tax laws. The Company makes matching contributions of up to 4% of an employee’s eligible compensation. The Company, at its discretion, may make additional matching and profit sharing contributions. For the year ended December 31, 2017 , 2016 and 2015 , these additional contributions totaled 3% of employee eligible compensation. For the year ended December 31, 2017 , 2016 and 2015 , expenses under the 401(k)/profit sharing plan were $2.3 million , $2.2 million , and $1.5 million , respectively. The increase in expense for the year ended December 31, 2017 compared to the year ended December 31, 2016 was due to an increase in employee eligible compensation, while the expense increase for the year ended December 31, 2016 compared to the year ended December 31, 2015 was driven by the SBM acquisition in the fourth quarter of 2015. SERP and Other Postretirement Benefit Plan The Company sponsors unfunded, non-qualified SERPs for certain officers. These agreements are designed to make up the shortfall (when compared to a non-highly compensated employee) in replacing income at retirement due to IRS compensation and benefit limits under the 401(k) plan and Social Security. With a SERP in place, participants should be able to replace 65 – 75% of their final average compensation. For those eligible for benefits, the SERP provides for a minimum 15 -year guaranteed benefit for all vested participants. In addition, the Company provides medical and life insurance to certain eligible retired employees under the other postretirement benefit plan. The following table summarizes changes in the benefit obligation and plan assets for (i) SERP and (ii) the other postretirement benefit plan as of December 31, 2017 and 2016 : SERP Other Postretirement Benefits 2017 2016 2017 2016 Benefit obligations: Beginning of year $ 11,523 $ 11,052 $ 3,635 $ 3,447 Service cost 335 308 53 59 Interest cost 452 432 144 151 Actuarial loss 1,955 219 110 143 Benefits paid (475 ) (488 ) (151 ) (165 ) End of year 13,790 11,523 3,791 3,635 Fair value of plan assets: Beginning of year — — — — Employer contributions 475 488 151 165 Benefits paid (475 ) (488 ) (151 ) (165 ) End of year — — — — Unfunded status at end of year (1) $ 13,790 $ 11,523 $ 3,791 $ 3,635 Amounts recognized in AOCI, net of tax: Net actuarial loss $ 3,504 $ 1,791 $ 654 $ 495 Prior service credit — — (170 ) (156 ) Total $ 3,504 $ 1,791 $ 484 $ 339 (1) Presented within other liabilities on the consolidated statements of condition. The accumulated benefit obligation for the SERP at December 31, 2017 and 2016 was $12.3 million and $10.7 million , respectively. For the year ending December 31, 2018, the estimated actuarial loss on the SERP that will be amortized from AOCI into net periodic benefit cost is $561,000 . All prior service costs have been fully amortized. For the year ending December 31, 2018, the estimated actuarial loss and prior service credit on other postretirement benefits that will be amortized from AOCI into net periodic benefit cost is $53,000 and $24,000 , respectively. The components of net periodic benefit cost and other amounts recognized in OCI, before taxes, were as follows: SERP Other Postretirement Benefits 2017 2016 2015 2017 2016 2015 Net periodic benefit cost: Service cost $ 335 $ 308 $ 307 $ 53 $ 59 $ 62 Interest cost 452 432 424 144 151 117 Recognized net actuarial loss 246 220 218 41 30 24 Amortization of prior service cost (credit) — 7 19 (24 ) (22 ) (22 ) Net periodic benefit cost 1,033 967 968 214 218 181 Changes in funded status recognized in OCI, before taxes: Net actuarial (gain) loss arising during period 1,955 219 (32 ) 110 143 92 Reclassifications to net period benefit cost: Amortization of net unrecognized actuarial loss (246 ) (220 ) (218 ) (41 ) (30 ) (24 ) Amortization of prior service (cost) credit — (7 ) (19 ) 24 22 22 Total recognized in OCI, before taxes 1,709 (8 ) (269 ) 93 135 90 Total recognized in net periodic benefit cost and OCI, before taxes $ 2,742 $ 959 $ 699 $ 307 $ 353 $ 271 The following assumptions were used in determining benefit obligations and net period benefit costs: SERP Other Postretirement Benefits 2017 2016 2015 2017 2016 2015 Weighted-average assumptions as of end of year: Discount rate for benefit obligation 3.60 % 4.00 % 4.00 % 3.55 % 4.00 % 4.50 % Discount rate for net periodic benefit cost 4.00 % 4.00 % 4.00 % 4.00 % 4.50 % 4.00 % Rate of compensation increase for benefit obligation 5.00 % 4.00 % 4.00 % — — — Rate of compensation increase for net periodic benefit cost 5.00 % 4.00 % 4.00 % — — — Health care cost trend rate assumed for future years — — — 6.50 % 7.00 % 7.00 % A 1.0% increase or decrease in the assumed health care cost trend rate would not materially increase or decrease the Company's accumulated postretirement benefit obligation and the related service and interest cost as of December 31, 2017 . The postretirement plan has a built-in cap on annual benefits to participants and, thus, the accumulated postretirement benefit obligation and the assumed health care cost trend are relatively stable each period. For the year ending December 31, 2018, the expected contribution is $473,000 for the SERP and $156,000 for the other postretirement benefits plan. The expected benefit payments for the next ten years are presented in the following table: SERP Other Postretirement Benefits 2018 473 156 2019 477 168 2020 486 173 2021 536 175 2022 566 187 2023-2027 2,246 1,061

Other Non-Interest Income and E

Other Non-Interest Income and Expenses	12 Months Ended
	Dec. 31, 2017
Other Noninterest Expenses [Abstract]
Other Non-Interest Expenses	Other Non-Interest Income and Expenses Detail of other income included in the consolidated statements of income is as follows: For The Year Ended December 31, Other income 2017 2016 2015 Customer loan swap fee income (1) $ 1,574 $ 2,104 $ 1,514 Other income 1,545 4,830 2,363 Total $ 3,119 $ 6,934 $ 3,877 (1) Fee income recognized upon completion of customer loan swaps. Refer to Note 18 for further discussion. Detail of other expenses included in the consolidated statements of income is as follows: For The Year Ended December 31, Other expenses 2017 2016 2015 Donations and marketing $ 1,852 $ 1,660 $ 1,841 Employee-related costs (1) 1,710 1,616 1,437 Postage, freight, and courier 1,655 1,754 1,430 Other expenses 5,731 5,657 4,502 Total $ 10,948 $ 10,687 $ 9,210 (1) Employee-related costs include hiring, training, education, meeting and business travel costs.

Commitments, Contingencies and

Commitments, Contingencies and Derivatives	12 Months Ended
	Dec. 31, 2017
Commitments and Contingencies Disclosure [Abstract]
Commitments, Contingencies and Derivatives	Commitments, Contingencies and Derivatives Legal Contingencies In the normal course of business, the Company and its subsidiaries are subject to pending and threatened legal actions. Although the Company is not able to predict the outcome of such actions, after reviewing pending and threatened actions with counsel, management believes that based on the information currently available the outcome of such actions, individually or in the aggregate, will not have a material adverse effect on the Company’s consolidated financial statements. Reserves are established for legal claims only when losses associated with the claims are judged to be probable, and the loss can be reasonably estimated. In many lawsuits and arbitrations, it is not possible to determine whether a liability has been incurred or to estimate the ultimate or minimum amount of that liability until the case is close to resolution, in which case a reserve will not be recognized until that time. As of December 31, 2017 and 2016 , the Company did no t have any material loss contingencies that were provided for and/or disclosure was necessary. Financial Instruments In the normal course of business, the Company is a party to both on- and off-balance sheet financial instruments involving, to varying degrees, elements of credit risk and interest rate risk in addition to the amounts recognized in the consolidated statements of condition. The following is a summary of the contractual and notional amounts of the Company’s financial instruments: December 31, 2017 2016 Lending-Related Instruments: Loan origination commitments and unadvanced lines of credit: Home equity $ 477,401 $ 454,225 Commercial and commercial real estate 49,482 83,103 Residential 41,368 17,795 Letters of credit 2,848 2,580 Other commitments 523 432 Derivative Financial Instruments: Customer loan swaps $ 703,336 $ 532,526 FHLBB advance interest rate swaps 50,000 50,000 Junior subordinated debt interest rate swaps 43,000 43,000 Fixed-rate mortgage interest rate lock commitments 21,746 15,249 Forward delivery commitments 8,065 15,125 Lending-Related Instruments The contractual amounts of the Company’s lending-related financial instruments do not necessarily represent future cash requirements since certain of these instruments may expire without being funded and others may not be fully drawn upon. These instruments are subject to the Company’s credit approval process, including an evaluation of the customer’s creditworthiness and related collateral requirements. Commitments generally have fixed expiration dates or other termination clauses. Derivative Financial Instruments The Company uses derivative financial instruments for risk management purposes (primarily interest rate risk) and not for trading or speculative purposes. The Company controls the credit risk of these instruments through collateral, credit approvals and monitoring procedures. Additionally, as part of Company's normal mortgage origination process, it provides the borrower with the option to lock their interest rate based on current market prices. During the period from commitment date to the loan closing date, the Company is subject to the risk of interest rate change. In an effort to mitigate such risk the Company may enter into forward delivery sales commitments, typically on a best-efforts basis, with certain approved investors. The Company accounts for its interest rate lock commitments on loans within the normal origination process for which it intends to sell as a derivative instrument. Furthermore, the Company records a derivative for its best-effort forward delivery commitments upon origination of a loan identified as held for sale. Should the Company enter into a forward delivery commitment on a mandatory delivery arrangement with an investor it accounts for the forward delivery commitment upon execution of the contract. Derivative instruments are carried at fair value in the Company’s financial statements. The accounting for changes in the fair value of a derivative instrument is dependent upon whether or not it qualifies and has been designated as a hedge for accounting purposes, and further, by the type of hedging relationship. The Company has designated its interest rate swaps on its junior subordinated debentures and its interest rate swaps on forecasted 30-day FHLBB borrowings as cash flow hedges. The change in the fair value of the Company's cash flow hedges is accounted for within OCI, net of tax. Quarterly, in conjunction with financial reporting, the Company assesses each cash flow hedge for ineffectiveness. To the extent ineffectiveness is identified, this amount is recorded within the consolidated statements of income. Furthermore, the Company will reclassify the gain or loss on the effective portion of the cash flow hedge from OCI into interest expense within the consolidated statements of income in the period the hedged transaction affects earnings. The change in fair value of the Company's other derivative instruments, not designated and qualifying as hedges, are accounted for within the consolidated statements of income. Customer Loan Swaps: The Bank will enter into interest rate swaps with its commercial customers, from time to time, to provide them with a means to lock into a long-term fixed rate, while simultaneously the Bank enters into an arrangement with a counterparty to swap the fixed rate to a variable rate to allow it to effectively manage its interest rate exposure. The Bank's customer loan level derivative program is not designated as a hedge for accounting purposes. As the interest rate swap agreements have substantially equivalent and offsetting terms, they do not materially change the Bank's interest rate risk or present any material exposure to the Company's consolidated statements of income. The Company records its customer loan swaps at fair value and presents such on a gross basis within other assets and accrued interest and other liabilities on the consolidated statements of condition. The following table presents the total positions, notional and fair value of the Bank's customer loans swaps with its commercial customers and the corresponding interest rate swap agreements with counterparty for the periods indicated: December 31, 2017 2016 Balance Sheet Location Number of Positions Notional Fair Value Number of Positions Notional Fair Value Receive fixed, pay variable Other assets / (accrued interest and other liabilities) 42 $ 226,884 $ (5,036 ) 50 $ 266,263 $ (1,945 ) Receive fixed, pay variable Other assets / (accrued interest and other liabilities) 23 124,784 1,799 — — — Pay fixed, receive variable Other assets / (accrued interest and other liabilities) 65 351,668 3,237 50 266,263 1,945 Total 130 $ 703,336 $ — 100 $ 532,526 $ — The Bank seeks to mitigate its customer counterparty credit risk exposure through its loan policy and underwriting process, which includes credit approval limits, monitoring procedures, and obtaining collateral, where appropriate. The Bank seeks to mitigate its institutional counterparty credit risk exposure by limiting the institutions for which it will enter into interest swap arrangements through an approved listing by the Company's Board of Directors. The Company has entered into a master netting arrangement with its counterparty and settles payments with the counterparty quarterly on a net basis. The Bank's arrangement with its institutional counterparty requires it to post cash or other assets as collateral for its FHLBB advance interest rate swap and customer loan swap contracts in a net liability position based on their fair values and the Bank's credit rating or receive cash collateral for contracts in a net asset position as requested. FHLBB Advance Interest Rate Swaps: On February 25, 2015, the Bank entered into two one-year forward-starting interest rate swap arrangements with a counterparty on two tranches of 30-day FHLBB advances with a total notional amount of $50.0 million . Each derivative arrangement commenced on February 25, 2016, with one contract that matured on February 25, 2018 and the other set to mature on February 25, 2019. The Bank entered into these interest rate swaps to mitigate its interest rate exposure on borrowings in a rising interest rate environment. The Bank has designated each arrangement as a cash flow hedge in accordance with GAAP, and, therefore, the change in unrealized gains or losses on the derivative instruments is recorded within AOCI, net of tax. Also, quarterly, in conjunction with financial reporting, the Company assesses each derivative instrument for ineffectiveness. To the extent any significant ineffectiveness is identified this amount would be recorded within the consolidated statements of income. For the year ended December 31, 2017, 2016 and 2015, the Company did no t record any ineffectiveness on these cash flow hedges within the consolidated statements of income. The Bank's arrangement with the counterparty requires it to post cash collateral for its FHLBB advance interest rate swap and customer loan swap contracts in a net liability position based on their fair values and the Bank's credit rating. If the interest rate swaps are in a net asset position based on their fair value, the counterparty will post collateral to the Bank as requested. The collateral posted by the Company (or counterparty) is not readily available and is presented within cash and due from banks on the consolidated statements of condition. At December 31, 2017, the Bank did not hold any cash at a correspondent bank as collateral on its FHLBB advance interest rate swap and customer loan swap contracts. The details of the FHLBB advance interest rate swaps for the periods indicated were as follows: December 31, 2017 2016 Notional Trade Maturity Date Variable Index Fixed Rate Fair Value (1) Fair Value (2) $ 25,000 2/25/2015 2/25/2018 1-Month USD LIBOR 1.54% $ 20 $ (152 ) 25,000 2/25/2015 2/25/2019 1-Month USD LIBOR 1.74% 1 (237 ) $ 50,000 $ 21 $ (389 ) (1) Presented within other assets on the consolidated statements of condition. (2) Presented within accrued interest and other liabilities on the consolidated statements of condition. Net payments to the counterparty for the year ended December 31, 2017 and 2016 were $288,000 and $490,000 , respectively, and have been classified as cash flows from operating activities in the consolidated statements of cash flows. Junior Subordinated Debt Interest Rate Swaps: The Company, from time to time, will enter into an interest rate swap agreement with a counterparty to manage interest rate risk associated with its variable rate borrowings. The Company has entered into a master netting arrangement with its counterparty and settles payments with the counterparty quarterly on a net basis. The interest rate swap arrangements contain provisions that require the Company to post cash or other assets as collateral with the counterparty for contracts that are in a net liability position based on their fair values and the Company’s credit rating. If the interest rate swaps are in a net asset position based on their fair value, the counterparty will post collateral to the Company as requested. At December 31, 2017, the Company had $8.1 million of cash posted as collateral to the counterparty. The collateral posted by the Company was not readily available and has been presented within cash and due from banks on the consolidated statements of condition. The details of the junior subordinated debt interest rate swaps for the periods indicated were as follows: December 31, 2017 2016 Notional Amount Trade Date Maturity Date Variable Index Received Fixed Rate Paid Fair Value (1) Fair Value (1) $ 10,000 3/18/2009 6/30/2021 3-Month USD LIBOR 5.09% $ (527 ) $ (806 ) 10,000 7/8/2009 6/30/2029 3-Month USD LIBOR 5.84% (2,133 ) (2,321 ) 10,000 5/6/2010 6/30/2030 3-Month USD LIBOR 5.71% (2,129 ) (2,290 ) 5,000 3/14/2011 3/30/2031 3-Month USD LIBOR 4.35% (1,137 ) (1,211 ) 8,000 5/4/2011 7/7/2031 3-Month USD LIBOR 4.14% (1,645 ) (1,744 ) $ 43,000 $ (7,571 ) $ (8,372 ) (1) Presented within accrued interest and other liabilities on the consolidated statements of condition. For the year ended December 31, 2017, 2016 and 2015, the Company did not record any ineffectiveness on these cash flow hedges within the consolidated statements of income. Net payments to the counterparty for the year ended December 31, 2017, 2016 and 2015 were $1.3 million , $1.5 million and $1.7 million , respectively, and were classified as cash flows from operating activities in the consolidated statements of cash flows. Fixed-Rate Mortgage Interest Rate Locks Commitments: As part of the origination process of a residential loan, the Company may enter into a rate lock agreement with its borrower, which is considered a fixed-rate mortgage interest rate lock commitment. If the Company has the intention to sell the loan upon origination, it will account for the interest rate lock commitment as a derivative. Our pipeline of mortgage loans with fixed-rate interest rate lock commitments were as follows for the periods indicated: December 31, 2017 2016 Balance Sheet Location Notional Fair Value Notional Fair Value Fixed-rate mortgage interest rate locks Other assets $ 19,886 $ 307 $ 12,310 $ 202 Fixed-rate mortgage interest rate locks Accrued interest and other liabilities 1,860 (22 ) 2,939 (15 ) Total $ 21,746 $ 285 $ 15,249 $ 187 For the year ended December 31, 2017, 2016 and 2015, the net unrealized gain from the change in fair value on the Company's mortgage interest rate locks reported within mortgage banking income, net, on the consolidated statements of income were $98,000 , $48,000 , and $139,000 , respectively. Forward Delivery Commitments: The Company typically enters into a forward delivery commitment with a secondary market investor, which has been approved by the Company within its normal governance process, at the onset of the loan origination process. The Company may enter into these arrangements with the secondary market investors on a best effort or mandatory delivery basis. The Company's normal practice has been to enter into these arrangements on a best effort basis. The Company enters into these arrangements with the secondary market investors to manage its interest rate exposure. The Company accounts for the forward delivery commitment as a derivative (but does not designate as a hedge) upon origination of a loan for which it intends to sell. The Company's forward delivery commitments on loans held for sale was as follows for the periods indicated: December 31, 2017 2016 Balance Sheet Location Notional Fair Value Notional Fair Value Forward delivery commitments ("best-effort") Other assets $ 6,692 $ 158 $ 14,250 $ 587 Forward delivery commitments ("best-effort") Accrued interest and other liabilities 1,373 (16 ) 875 (309 ) Total $ 8,065 $ 142 $ 15,125 $ 278 For the year ended December 31, 2017, 2016 and 2015, the net unrealized (loss) gain from the change in fair value on the Company's forward delivery commitments reported within mortgage banking income, net on the consolidated statements of income were $(136,000) , $278,000 , and $0 , respectively. The table below presents the effect of the Company’s derivative financial instruments included in OCI and current earnings for the periods indicated: For The Year Ended 2017 2016 2015 Derivatives designated as cash flow hedges Effective portion of unrealized losses recognized within AOCI during the period, net of tax $ (248 ) $ (637 ) $ (1,533 ) Net reclassification adjustment for effective portion of cash flow hedges included in interest expense, gross (1) $ 1,592 $ 2,026 $ 1,695 (1) Reclassified into the consolidated statements of income within interest expense. The Company expects approximately $936,000 (pre-tax) to be reclassified to interest expense from OCI, related to the Company’s cash flow hedges, in the next twelve months. This reclassification is due to anticipated payments that will be made and/or received on the swaps based upon the forward curve as of December 31, 2017 .

Fair Value

Fair Value	12 Months Ended
	Dec. 31, 2017
Fair Value Disclosures [Abstract]
Fair Value	Fair Value Fair value is the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. Fair value is best determined using quoted market prices. However, in many instances, quoted market prices are not available. In such instances, fair values are determined using various valuation techniques. Various assumptions and observable inputs must be relied upon in applying these techniques. GAAP establishes a fair value hierarchy for valuation inputs that gives the highest priority to quoted prices in active markets for identical assets or liabilities and the lowest priority to unobservable inputs. GAAP permits an entity to choose to measure certain eligible financial instruments and other items at fair value. The Company elected the fair value option for its loans held for sale. Electing the fair value option for loans held for sale enables the Company’s financial position to more clearly align with the economic value of the actively traded asset. The fair value hierarchy for valuation of an asset or liability is as follows: Level 1: Valuation is based upon unadjusted quoted prices in active markets for identical assets and liabilities that the entity has the ability to access as of the measurement date. Level 2: Valuation is determined from quoted prices for similar assets or liabilities in active markets, from quoted prices for identical or similar instruments in markets that are not active or by model-based techniques in which all significant inputs are observable in the market. Level 3: Valuation is derived from model-based and other techniques in which at least one significant input is unobservable and which may be based on the Company’s own estimates about the assumptions that market participants would use to value the asset or liability. In general, fair value is based upon quoted market prices, where available. If such quoted market prices are not available, fair value is based upon model-based techniques incorporating various assumptions including interest rates, prepayment speeds and credit losses. Assets and liabilities valued using model-based techniques are classified as either Level 2 or Level 3, depending on the lowest level classification of an input that is considered significant to the overall valuation. A description of the valuation methodologies used for instruments measured at fair value, as well as the general classification of such instruments pursuant to the valuation hierarchy, is set forth below. Financial Instruments Recorded at Fair Value on a Recurring Basis Loans Held For Sale: The fair value of loans held for sale is determined using quoted secondary market prices or executed sales agreements and is classified as Level 2. AFS Securities : The fair value of debt AFS securities is reported utilizing prices provided by an independent pricing service based on recent trading activity and other observable information including, but not limited to, dealer quotes, market spreads, cash flows, market interest rate curves, market consensus prepayment speeds, credit information, and the bond’s terms and conditions. The fair value of debt securities are classified as Level 2. The fair value of equity AFS securities is reported utilizing market prices based on recent trading activity and dealer quotes. The equity securities are traded on inactive markets and are classified as Level 2. Derivatives : The fair value of the Company's interest rate swaps, including its junior subordinated debt interest rate swaps, FHLBB advance interest rate swaps and customer loan swaps, are determined using inputs that are observable in the market place obtained from third parties including yield curves, publicly available volatilities, and floating indexes and, accordingly, are classified as Level 2 inputs. The credit value adjustments associated with derivatives utilize Level 3 inputs, such as estimates of current credit spreads to evaluate the likelihood of default by the Company and its counterparties. As of December 31, 2017 and 2016 , the Company 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 due to collateral postings. The fair value of the Company's fixed rate interest rate lock commitments are determined using secondary market pricing for loans with similar structures, including term, rate and borrower credit quality, adjusted for the Company's pull-through rate estimate (i.e. estimate of loans within its pipeline that will ultimately complete the origination process and be funded). The Company has classified its fixed rate interest rate lock commitments as Level 2 as the quoted secondary market prices are the more significant input, and while the Company's internal pull-through rate estimate is a Level 3 estimate it is not as critical to the ultimate valuation. The fair value of the Company's forward delivery commitments are determined using secondary market pricing for loans with similar structures, including term, rate and borrower credit quality, and the locked and agreed to price with the secondary market investor. The Company has classified its fixed rate interest rate lock commitments as Level 2. The following table summarizes financial assets and financial liabilities measured at fair value on a recurring basis as of December 31, 2017 and 2016 , segregated by the level of the valuation inputs within the fair value hierarchy utilized to measure fair value: Fair Value Readily Available Market Prices (Level 1) Observable Market Data (Level 2) Company Determined Fair Value (Level 3) December 31, 2017 Financial assets: Loans held for sale $ 8,103 $ — $ 8,103 $ — AFS securities: Obligations of states and political subdivisions 7,335 — 7,335 — Mortgage-backed securities issued or guaranteed by U.S. government-sponsored enterprises 503,302 — 503,302 — Collateralized mortgage obligations issued or guaranteed by U.S. government-sponsored enterprises 272,799 — 272,799 — Subordinated corporate bonds 5,657 — 5,657 — Equity securities 806 — 806 — Customer loan swaps 5,036 — 5,036 — Fixed-rate mortgage interest rate lock commitments 307 — 307 — Forward delivery commitments 158 — 158 — FHLBB advance interest rate swaps 21 — 21 — Financial liabilities: Junior subordinated debt interest rate swaps 7,571 — 7,571 — Customer loan swaps 5,036 — 5,036 — Fixed-rate mortgage interest rate lock commitments 22 — 22 — Forward delivery commitments 16 — 16 — December 31, 2016 Financial assets: Loans held for sale $ 14,836 $ — $ 14,836 $ — AFS securities: Obligations of states and political subdivisions 9,001 — 9,001 — Mortgage-backed securities issued or guaranteed by U.S. government-sponsored enterprises 480,622 — 480,622 — Collateralized mortgage obligations issued or guaranteed by U.S. government-sponsored enterprises 283,890 — 283,890 — Subordinated corporate bonds 5,613 — 5,613 — Equity securities 741 — 741 — Customer loan swaps 1,945 — 1,945 — Fixed-rate mortgage interest rate lock commitments 202 — 202 — Forward delivery commitments 587 — 587 — Financial liabilities: Junior subordinated debt interest rate swaps 8,372 — 8,372 — FHLBB advance interest rate swaps 389 — 389 — Customer loan swaps 1,945 — 1,945 — Fixed-rate mortgage interest rate lock commitments 15 — 15 — Forward delivery commitments 309 — 309 — The Company did not have any transfers between Level 1 and Level 2 of the fair value hierarchy for the year ended December 31, 2017 . The Company’s policy for determining transfers between levels occurs at the end of the reporting period when circumstances in the underlying valuation criteria change and result in transfer between levels. Financial Instruments Recorded at Fair Value on a Nonrecurring Basis The Company may be required, from time to time, to measure certain financial assets and financial liabilities at fair value on a nonrecurring basis in accordance with GAAP. These include assets that are measured at the lower of cost or fair value that were recognized at fair value below cost at the end of the period. Collateral-Dependent Impaired Loans : Loans for which it is probable that payment of interest and principal will not be made in accordance with the contractual terms of the loan agreement are considered impaired. Effective January 1, 2017 the Company's policy is to individually evaluate for impairment loans with a principal balance greater than $500,000 or more and are classified as substandard or doubtful and are on non-accrual status. Prior to January 1, 2017, the Company's policy was to individually evaluate for impairment loans with a principal balance greater than $250,000 or more and was classified as substandard or doubtful and was on non-accrual status. Once the population of loans is identified for individual impairment assessment, the Company measures these loans for impairment by comparing net realizable value, which is the fair value of the collateral, less estimated costs to sell, to the carrying value of the loan. If the net realizable value of the loan is less than the carrying value of the loan, then a loss is recognized as part of the ALL to adjust the loan's carrying value to net realizable value. Accordingly, certain collateral-dependent impaired loans are subject to measurement at fair value on a non-recurring basis. Management has estimated the fair values of these assets using Level 2 inputs, such as the fair value of collateral based on independent third-party market approach appraisals for collateral-dependent loans, and Level 3 inputs where circumstances warrant an adjustment to the appraised value based on the age of the appraisal and/or comparable sales, condition of the collateral, and market conditions. Servicing Assets : The Company accounts for mortgage servicing assets at cost, subject to impairment testing. When the carrying value of a tranche exceeds fair value, a valuation allowance is established to reduce the carrying cost to fair value. Fair value is based on a valuation model that calculates the present value of estimated net servicing income. The Company obtains a third-party valuation based upon loan level data including note rate, type and term of the underlying loans. The model utilizes two significant unobservable inputs, which are loan prepayment assumptions and the discount rate used, to calculate the fair value of each tranche, and as such, the Company has classified within Level 3 of the fair value hierarchy. Non-Financial Assets and Non-Financial Liabilities Recorded at Fair Value on a Nonrecurring Basis The Company has no non-financial assets or non-financial liabilities measured at fair value on a recurring basis. Non-financial assets measured at fair value on a non-recurring basis consist of OREO and goodwill. OREO : OREO properties acquired through foreclosure or deed in lieu of foreclosure are recorded at net realizable value, which is the fair value of the real estate, less estimated costs to sell. Any write-down of the recorded investment in the related loan is charged to the ALL upon transfer to OREO. Upon acquisition of a property, a current appraisal is used or an internal valuation is prepared to substantiate fair value of the property. After foreclosure, management periodically, but at least annually, obtains updated valuations of the OREO properties and, if additional impairments are deemed necessary, the subsequent write-downs for declines in value are recorded through a valuation allowance and a provision for losses charged to other non-interest expense within the consolidated statements of income. As management considers appropriate, adjustments are made to the appraisal obtained for the OREO property to account for recent sales activity of comparable properties, changes in the condition of the property, and changes in market conditions. These adjustments are not observable in an active market and are classified as Level 3. Goodwill and Other Intangible Assets : Goodwill represents the excess cost of an acquisition over the fair value of the net assets acquired. The fair value of goodwill is estimated by utilizing several standard valuation techniques, including discounted cash flow analyses, bank merger multiples, and/or an estimation of the impact of business conditions and investor activities on the long-term value of the goodwill. Should an impairment of either reporting unit's goodwill occur, the associated goodwill is written-down to fair value and the impairment charge is recorded within non-interest expense in the consolidated statements of income. The Company conducts an annual impairment test of goodwill in the fourth quarter each year, or more frequently as necessary. There were no indications or triggering events for the year ended December 31, 2017 or 2016 for which management believed that it was more likely than not that goodwill is impaired. The Company's core deposit intangible assets represent the estimated value of acquired customer relationships and are amortized on a straight-line basis over the estimated life of those relationships. Core deposit intangibles are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount may not be recoverable. If necessary, management will test the core deposit intangibles for impairment by comparing its carrying value to the expected undiscounted cash flows of the assets. If the undiscounted cash flows of the intangible assets exceed its carrying value then the intangible assets are deemed to be fully recoverable and not impaired. However, if the undiscounted cash flows of the intangible assets are less than its carrying value than an impairment charge is recorded to mark the carrying value of the intangible assets to fair value. There were no indications or triggering events for the year ended December 31, 2017 or 2016 for which management believes that the carrying amount may not be recoverable. The table below highlights financial and non-financial assets measured and recorded at fair value on a non-recurring basis as of December 31, 2017 and 2016 : Fair Value Readily Available Market Prices (Level 1) Observable Market Data (Level 2) Company Determined Fair Value (Level 3) December 31, 2017 Financial assets: Collateral-dependent impaired loans $ 3,696 $ — $ — $ 3,696 Servicing assets (1) — — — — Non-financial assets: OREO 130 — — 130 December 31, 2016 Financial assets: Collateral-dependent impaired loans $ 500 $ — $ — $ 500 Servicing assets (1) 1,090 — — 1,090 Non-financial assets: OREO 922 — — 922 (1) Represents mortgage serving assets deemed to be impaired and a valuation allowance was established to carry at fair value at December 31, 2017 and 2016 . The following table presents the valuation methodology and unobservable inputs for Level 3 assets measured at fair value on a non-recurring basis at December 31, 2017 and 2016 : Fair Value Valuation Methodology Unobservable input Discount Range (Weighted-Average) December 31, 2017 Collateral-dependent impaired loans: Partially charged-off $ 86 Market approach appraisal of collateral Management adjustment of appraisal 0 - 50% (18%) Estimated selling costs 0 - 10% (6%) Specifically reserved 3,610 Market approach appraisal of collateral Management adjustment of appraisal 0% (0%) Estimated selling costs 10% (10%) OREO 130 Market approach appraisal of collateral Management adjustment of appraisal 20% (20%) Estimated selling costs 10% (10%) December 31, 2016 Collateral-dependent impaired loans: Partially charged-off $ 166 Market approach appraisal of collateral Management adjustment of appraisal 0% (0%) Estimated selling costs 0 - 10% (5%) Specifically reserved 334 Market approach appraisal of collateral Management adjustment of appraisal 0 - 50% (13%) Estimated selling costs 10% (10%) OREO 922 Market approach appraisal of collateral Management adjustment of appraisal 0 - 73% (7%) Estimated selling costs 10% (10%) GAAP requires disclosure of the fair value of financial assets and financial liabilities, including those financial assets and financial liabilities that are not measured and reported at fair value on a recurring basis or non-recurring basis. The methodologies for estimating the fair value of financial assets and financial liabilities that are measured at fair value on a recurring or non-recurring basis are discussed above. The following methods and assumptions were used by the Company in estimating the fair values of its other financial instruments. Cash and Due from Banks : The carrying amounts reported in the consolidated statements of condition approximate fair value that have original maturities of ninety days or less. HTM securities : The fair value is estimated utilizing prices provided by an independent pricing service based on recent trading activity and other observable information including, but not limited to, dealer quotes, market spreads, cash flows, market interest rate curves, market consensus prepayment speeds, credit information, and the bond’s terms and conditions. The fair value is classified as Level 2. Loans : For variable rate loans that reprice frequently and have no significant change in credit risk, fair values are based on carrying values. The fair value of other loans is estimated by discounting the future cash flows using the current rates at which similar loans would be made to borrowers with similar credit ratings and for the same remaining maturities. Interest Receivable and Payable : The carrying amounts reported in the consolidated statements of condition approximate fair value. Deposits : The fair value of demand, non-interest checking, savings and money market deposits is determined as the amount payable on demand at the reporting date. The fair value of time deposits is estimated by discounting the estimated future cash flows using market rates offered for deposits of similar remaining maturities. Borrowings : The carrying amounts of short-term borrowings from the FHLB, securities sold under repurchase agreements, notes payable and other short-term borrowings approximate fair value. The fair values of long-term borrowings and commercial repurchase agreements are based on the discounted cash flows using current rates for advances of similar remaining maturities. Subordinated Debentures : The fair values of are based on quoted prices from similar instruments in inactive markets. The following table presents the carrying amounts and estimated fair value for financial instrument assets and liabilities at December 31, 2017 : Carrying Amount Fair Value Readily Available Market Prices (Level 1) Observable Market Prices (Level 2) Company Determined Market Prices (Level 3) Financial assets: Cash and due from banks $ 102,971 $ 102,971 $ 102,971 $ — $ — AFS securities 789,899 789,899 — 789,899 — HTM securities 94,073 94,913 — 94,913 — Loans held for sale 8,103 8,103 — 8,103 — Residential real estate loans (1) 853,283 853,056 — — 853,056 Commercial real estate loans (1) 1,152,160 1,115,618 — — 1,115,618 Commercial loans (1)(2) 413,898 401,902 — — 401,902 Home equity loans (1) 321,011 318,230 — — 318,230 Consumer loans (1) 17,916 17,335 — — 17,335 Servicing assets 1,025 1,766 — 1,766 — Interest receivable 9,595 9,595 — 9,595 — Customer loan swaps 5,036 5,036 — 5,036 — Fixed-rate mortgage interest rate lock commitments 307 307 — 307 — Forward delivery commitments 158 158 — 158 — FHLBB advance interest rate swaps 21 21 — 21 — Financial liabilities: Deposits $ 3,000,491 $ 2,995,269 $ — $ 2,995,269 $ — Short-term borrowings 541,867 541,683 — 541,683 — Long-term borrowings 10,720 10,699 — 10,699 — Subordinated debentures 58,911 44,333 — 44,333 — Interest payable 564 564 — 564 — Junior subordinated debt interest rate swaps 7,571 7,571 — 7,571 — Customer loan swaps 5,036 5,036 — 5,036 — Fixed-rate mortgage interest rate lock commitments 22 22 — 22 — Forward delivery commitments 16 16 — 16 — (1) The presented carrying amount is net of the allocated ALL. (2) Includes the HPFC loan portfolio. The following table presents the carrying amounts and estimated fair value for financial instrument assets and liabilities at December 31, 2016 : Carrying Amount Fair Value Readily Available Market Prices (Level 1) Observable Market Prices (Level 2) Company Determined Market Prices (Level 3) Financial assets: Cash and due from banks $ 87,707 $ 87,707 $ 87,707 $ — $ — AFS securities 779,867 779,867 — 779,867 — HTM securities 94,609 94,596 — 94,596 — Loans held for sale 14,836 14,836 — 14,836 — Residential real estate loans (1) 798,334 800,122 — — 800,122 Commercial real estate loans (1) 1,038,626 1,006,249 — — 1,006,249 Commercial loans (1)(2) 389,624 391,493 — — 391,493 Home equity loans (1) 327,713 327,292 — — 327,292 Consumer loans (1) 17,151 16,845 — — 16,845 Servicing assets 1,210 1,701 — 1,701 — Interest receivable 8,654 8,654 — 8,654 — Customer loan swaps 1,945 1,945 — 1,945 — Fixed-rate mortgage interest rate lock commitments 202 202 — 202 — Forward delivery commitments 587 587 — 587 — Financial liabilities: Deposits $ 2,828,529 $ 2,826,484 $ — $ 2,826,484 $ — Short-term borrowings 530,129 530,435 — 530,435 — Long-term borrowings 10,791 10,836 — 10,836 — Subordinated debentures 58,755 41,660 — 41,660 — Interest payable 534 534 — 534 — Junior subordinated debt interest rate swaps 8,372 8,372 — 8,372 — FHLBB advance interest rate swaps 389 389 — 389 — Customer loan swaps 1,945 1,945 — 1,945 — Fixed-rate mortgage interest rate lock commitments 15 15 — 15 — Forward delivery commitments 309 309 — 309 — (1) The presented carrying amount is net of the allocated ALL. (2) Includes the HPFC loan portfolio.

Parent Company Financial Statem

Parent Company Financial Statements	12 Months Ended
	Dec. 31, 2017
Condensed Financial Information of Parent Company Only Disclosure [Abstract]
Parent Company Financial Statements	Parent Company Financial Statements Following are the condensed statements of condition, income and cash flows for the Company's parent company: STATEMENTS OF CONDITION December 31, 2017 2016 ASSETS Cash $ 29,365 $ 29,905 Investment in subsidiary 444,235 429,100 Receivable from subsidiary 107 107 Other assets 14,806 12,420 Total assets $ 488,513 $ 471,532 LIABILITIES AND SHAREHOLDERS’ EQUITY Subordinated debentures $ 58,911 $ 58,755 Due to subsidiary 17 37 Other liabilities 26,172 21,193 Shareholders’ equity 403,413 391,547 Total liabilities and shareholders’ equity $ 488,513 $ 471,532 STATEMENTS OF INCOME For The Year Ended December 31, 2017 2016 2015 Operating Income Dividend income from subsidiary $ 16,800 $ 16,000 $ 39,200 Other income (loss) 145 239 (18 ) Total operating income 16,945 16,239 39,182 Operating Expenses Interest on borrowings 3,408 3,415 2,734 Fees to Bank 160 160 160 Other operating expenses 592 748 469 Total operating expenses 4,160 4,323 3,363 Income before equity in undistributed earnings of subsidiaries and income taxes 12,785 11,916 35,819 Equity in undistributed income (losses) of subsidiaries 17,405 26,773 (15,999 ) Income before income taxes 30,190 38,689 19,820 Income tax (expense) benefit (1,714 ) 1,378 1,132 Net Income $ 28,476 $ 40,067 $ 20,952 STATEMENTS OF CASH FLOWS For The Year Ended December 31, 2017 2016 2015 Operating Activities Net income $ 28,476 $ 40,067 $ 20,952 Adjustments to reconcile net income to net cash provided by operating activities: Equity in undistributed (income) losses of subsidiaries (17,405 ) (26,655 ) 4,573 Gain on sale of investment securities (32 ) (4 ) — (Increase) decrease in receivable from subsidiaries — 1,819 (1,901 ) (Increase) decrease in other assets (1,930 ) 1,213 (2,175 ) Increase (decrease) in due to subsidiaries (20 ) (1,179 ) 1,216 Increase (decrease) in other liabilities 3,721 (2,519 ) 320 Net cash provided by operating activities 12,810 12,742 22,985 Investing Activities Acquisition of SBM, net of cash acquired — — (25,319 ) Proceeds from sale of investment securities 110 84 — Net cash provided by (used in) investing activities 110 84 (25,319 ) Financing Activities Issuance of subordinated debt, net of issuance costs — — 14,464 Exercise of stock options and issuance of restricted stock, net of repurchase for tax withholdings and tax benefit (606 ) 894 753 Capital contribution from subsidiaries 1,469 1,997 836 Equity issuance costs — — (612 ) Cash dividends paid on common stock and cash in-lieu paid for fractional shares due to stock split (14,323 ) (12,393 ) (9,785 ) Net cash provided by (used in) financing activities (13,460 ) (9,502 ) 5,656 Net (decrease) increase in cash (540 ) 3,324 3,322 Cash at beginning of year 29,905 26,581 23,259 Cash at end of year $ 29,365 $ 29,905 $ 26,581

Quarterly Results of Operations

Quarterly Results of Operations (Unaudited)	12 Months Ended
	Dec. 31, 2017
Quarterly Financial Information Disclosure [Abstract]
Quarterly Results of Operations (Unaudited)	Quarterly Results of Operations (Unaudited) The following table presents a summary of the quarterly results of operations for the year ended: December 31, 2017 2016 First Quarter Second Quarter Third Quarter Fourth Quarter (1) First Quarter Second Quarter Third Quarter Fourth Quarter Interest income $ 32,414 $ 33,940 $ 34,710 $ 35,040 $ 31,981 $ 32,775 $ 32,594 $ 32,276 Interest expense 4,559 5,314 5,550 5,381 4,029 4,271 4,222 4,032 Net interest income 27,855 28,626 29,160 29,659 27,952 28,504 28,372 28,244 Provision for credit losses 579 1,401 817 238 872 2,852 1,279 255 Non-interest income 8,572 9,888 10,299 9,840 7,917 10,552 11,001 10,151 Non-interest expense 21,428 22,158 21,825 23,099 22,909 22,330 22,149 22,508 Income before income taxes 14,420 14,955 16,817 16,162 12,088 13,874 15,945 15,632 Income tax expense 4,344 4,721 5,478 19,335 3,442 4,258 5,042 4,730 Net income (loss) $ 10,076 $ 10,234 $ 11,339 $ (3,173 ) $ 8,646 $ 9,616 $ 10,903 $ 10,902 Per common share: Basic $ 0.65 $ 0.66 $ 0.72 $ (0.20 ) $ 0.56 $ 0.62 $ 0.70 $ 0.70 Diluted $ 0.64 $ 0.66 $ 0.72 $ (0.20 ) $ 0.56 $ 0.62 $ 0.70 $ 0.70 (1) In the fourth quarter of 2017, the Company recognized $14.3 million of additional income tax expense upon the revaluation of its deferred tax assets and liabilities upon enactment of the Tax Act on December 22, 2017, which lowered the federal corporate tax rate from 35.0% to 21.0%, effective January 1, 2018. The impact to fourth quarter 2017 basic and diluted EPS was $0.91 per share.

Business and Summary of Signi31

Business and Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2017
Accounting Policies [Abstract]
Principles of Consolidation	Principles of Consolidation . The accompanying consolidated financial statements include the accounts of the Company and the Bank (which includes the consolidated accounts of HPFC, Property A, Inc. and Property P, Inc.). All intercompany accounts and transactions have been eliminated in consolidation. Assets held by the Bank in a fiduciary capacity, through Camden National Wealth Management, are not assets of the Company and, therefore, are not included in the consolidated statements of condition. The Company also owns 100% of the common stock of CCTA and UBCT. These entities are unconsolidated subsidiaries of the Company.
Reclassifications	Reclassifications . Certain reclassifications have been made to prior year amounts to conform to the current year's presentation.
Use of Estimates	Use of Estimates . The preparation of the financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting periods. Actual results could vary from these estimates. Several estimates are particularly critical and are susceptible to significant near-term change, including the ALL, the accounting for business combinations including subsequent impairment analyses for goodwill and other intangible assets, accounting for income taxes, postretirement benefits and asset impairment judgments, including OTTI of investment securities.
Subsequent Events	Subsequent Events . The Company has evaluated events and transactions subsequent to December 31, 2017 for potential recognition or disclosure as required by GAAP.
Significant Concentration of Credit Risk	Significant Concentration of Credit Risk. The Bank grants loans primarily to customers in Maine. Although the Bank has a diversified loan portfolio, a large portion of the Bank's loans are secured by commercial or residential real estate located in Maine and is subject to volatility within Maine's real estate market. Furthermore, the debtors' ability to honor their contracts is highly dependent upon other economic factors throughout Maine. The Bank does not generally engage in non-recourse lending and typically will require the principals of any commercial borrower to obligate themselves personally on the loan.
Cash and Cash Equivalents	Cash and Cash Equivalents . For the purposes of reporting cash flows, cash and cash equivalents consist of cash on hand and amounts due from banks. The Bank is required by the FRB to maintain cash reserves equal to a percentage of deposits. The Company maintains the reserve balances in cash on hand or at the FRB.
Investment Securities	Investment Securities. Investment securities are classified at the time of purchase as AFS, HTM, or trading. The classification of investment securities are constantly re-evaluated for consistency with corporate goals and objectives. Trading securities are carried at fair value on the consolidated statements of condition with subsequent changes to fair value recorded in earnings. At December 31, 2017 and 2016, the Company did no t have any investment securities classified as trading securities on its consolidated statements of condition. Debt securities for which the Company has the positive intent and ability to hold to maturity are classified as HTM and recorded at amortized cost on the consolidated statements of condition. At December 31, 2017 and 2016, the Company had investment securities of $94.1 million and $94.6 million , respectively, classified as HTM and carried at amortized cost on its consolidated statements of condition. Investment securities that are not classified as HTM or trading securities are classified as AFS and are carried at fair value on the Company's consolidated statements of condition with subsequent changes to fair value recorded within AOCI, net of tax. At December 31, 2017 and 2016, the Company had investment securities of $789.9 million and $779.9 million , respectively, classified as AFS and carried at fair value on its consolidated statements of condition. Purchase premiums and discounts are recognized in interest income on the consolidated statements of income using the interest method over the period to maturity (or issuer call option date, if earlier) and are recorded on the trade date. Upon sale of an investment security designated as AFS, the unrealized gain or loss recorded within AOCI, net of tax, is reversed. Gains and losses on the sale of investment securities are recognized within non-interest income on the consolidated statements of income and are recorded on the trade date using the specific identification method. Management conducts a quarterly review and evaluation of its debt and equity securities portfolio to determine if the decline in fair value of any security appears to be other-than-temporary. The factors considered by management in its review include, but are not limited to: the length of time and the extent to which the fair value has been less than cost, the financial condition and near-term prospects of the issuer, the credit ratings of the security or issuer, whether the decline in fair value appears to be issuer specific or, alternatively, a reflection of general market or industry conditions, and the Company’s intent and ability to hold the security for a period of time sufficient to allow for a recovery in fair value. Should the Company determine that the decline in the fair value of an equity security was other-than-temporary, the Company recognizes the impairment on the equity security within non-interest income on the consolidated statements of income when identified. For debt securities where the Company does not intend to sell the security and it is not more-likely-than-not that the Company will be required to sell the security before recovery of its amortized cost basis, the other-than-temporary decline in the fair value of the debt security related to: (i) credit loss is recognized in non-interest income on the consolidated statements of income; and (ii) other factors is recognized in AOCI, net of tax. For debt securities where the Company intends to sell the security or more-likely-than-not will be required to sell the security before recovery of its amortized cost, the Company recognizes the OTTI equal to the entire difference between the security’s cost basis and its fair value within non-interest income on the consolidated statements of income. The
Loans Held for Sale	Loans Held for Sale. The Company has elected the fair value option for loans classified as held for sale on the consolidated statements of condition. Designation of loans as held for sale is determined based on the Company's intent and is, typically, completed as the loans are underwritten. The fair value for loans held for sale is determined using quoted secondary market prices or executed sales agreements. Management constantly evaluates its loan portfolio, in conjunction with asset/liability management practices, and will opt to sell certain loans, typically new 30 -year residential mortgages, to manage the Company's interest rate exposure and for other business purposes, including generating fee income through mortgage sale gains. At December 31, 2017 and 2016, the fair value of loans designated as held for sale on its consolidated statements of condition were $8.1 million and $14.8 million , respectively.
Interest and Fees on Loans	Originated Loans and Acquired Loans . Loans are reported at amortized cost, or fair value in the case of acquired loans, adjusted for any partial charge-offs and net of any deferred loan fees or costs. For originated loans, interest income is accrued based upon the daily principal amount outstanding except for loans on non-accrual status. For acquired loans, interest income is also accrued based upon the daily principal amount outstanding and is then further adjusted by the accretion of any discount or amortization of any premium associated with the loan. For originated loans, loan fees and certain direct origination costs are deferred and amortized into interest income over the contractual term of the loan using the level-yield method. When a loan is paid off, the unamortized portion is recognized in interest income. A loan is classified as non-accrual generally when it becomes 90 days past due as to interest or principal payments, or sooner if management considers such action to be prudent. All previously accrued but unpaid interest on non-accrual loans is reversed from interest income in the period in which the loan is considered delinquent and the amortization of any unamortized net deferred origination loan fees/costs stops. Interest payments received on non-accrual loans, including impaired loans, are applied as a reduction of principal. A loan remains on non-accrual status until all principal and interest amounts contractually due are brought current and future payments are reasonably assured. Should a loan transition from non-accrual status back to accrual status, the unrecognized interest earned during the period the loan was on non-accrual status and unamortized deferred origination fees and costs are recognized over the remaining contractual life of the loan using the level-yield method.
Goodwill and Core Deposit Intangible	Goodwill and Core Deposit Intangible Assets . Goodwill represents the excess cost of an acquisition over the fair value of the net assets acquired. Goodwill is not subject to amortization but rather is evaluated at least annually for impairment, or as events and circumstances dictate, at the reporting unit level. The Company's two reporting unit levels are (i) banking and (ii) financial services. The banking reporting unit is representative of the Company's core banking business line, while the financial services reporting unit is representative of the Company's wealth management and trust services business line. Any impairment is charged to non-interest expense on the consolidated statements of income. Goodwill is evaluated for impairment annually as of November 30 th , or more frequently should external and/or internal factors warrant such. The Company may utilize a qualitative analysis (commonly referred to as "step zero") and/or a quantitative analysis to evaluate its reporting units' goodwill for impairment. The Company may utilize the qualitative analysis for an individual reporting unit or for both reporting units any given year. Furthermore, the Company has the option to by-pass the qualitative analysis for any given year and perform the quantitative analysis. Using a qualitative analysis to assess a reporting unit's goodwill for impairment, the Company will consider various factors to determine if it is more-likely-than-not that a reporting unit's carrying value exceeds its fair value. These factors include, but are not limited to, the overall macro-economic environment; industry economic and regulatory environment; and company specific factors, including, but not limited to, performance, Company common stock share price, competition and/or significant changes in senior management. Should the Company determine it is more-likely-than-not that the carrying value of a reporting unit exceeds its fair value, then the Company would perform then perform the next step of the goodwill impairment test, which is a quantitative analysis. If the Company were to determine it is not more-likely-than-not that the carrying value of a reporting unit exceeds its fair value, the Company would have completed its goodwill impairment evaluation and concluded the reporting unit's goodwill was not impaired. After performing the qualitative analysis and determining it's more-likely-than-not that the carrying value of a reporting unit exceeds its fair value or if the Company by-passed the qualitative analysis, it would perform a quantitative analysis to determine if the carrying value of a reporting unit exceeds its fair value. The Company may use various valuation techniques such as a discounted cash flow model, a comparative market transaction multiple approach and/or other valuation methods, to determine the reporting unit's fair value. If the fair value of the reporting unit is greater than its carrying value, then the reporting unit is not deemed to be impaired and no further assessment is required. However, if the fair value of the reporting unit is less than its carrying value, the Company would then be required to fair value the tangible and identifiable intangible assets, and liabilities of the reporting unit, to derive an implied fair value of goodwill for the reporting unit. If the implied fair value of goodwill for the reporting unit is greater than its carrying value, then the reporting unit’s goodwill is not impaired. However, if the reporting unit’s implied fair value of goodwill is less than its carrying value, an impairment charge is then recorded to carry goodwill at its calculated implied fair value. The Company completed its annual goodwill impairment testing as of November 30, 2017 , 2016 and 2015 for each reporting unit and goodwill was not impaired. Core deposit intangible assets represents the estimated value of acquired customer relationships and is amortized on a straight-line basis over the estimated life of those relationships ( 5 to 10 years from the acquisition dates). Core deposit intangibles are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount may not be recoverable. If necessary, management will test the core deposit intangibles for impairment by comparing its carrying value to the expected undiscounted cash flows of the assets. If the undiscounted cash flows of the intangible assets exceed its carrying value then the intangible assets are deemed to be fully recoverable and not impaired. However, if the undiscounted cash flows of the intangible assets are less than its carrying value then management must compare the fair value of the intangible assets to its carrying value. If the fair value of the intangible assets exceeds its carrying value then the intangible assets are not impaired. If the fair value of the intangible assets is less than its carrying value then an impairment charge is recorded to mark the carrying value of the intangible assets to fair value. For the year ended December 31, 2017 , 2016 or 2015 , there were no events or changes in circumstances that indicated the carrying amount may not be recoverable.
Bank-Owned Life Insurance	BOLI . BOLI represents the cash surrender value of life insurance policies on the lives of certain active and retired employees where the Company is the beneficiary and is recorded as an asset on the Company's consolidated statements of condition. Increases in the cash surrender values of the policies, as well as death benefits received, net of any cash surrender value, are recorded in non-interest income on the consolidated statements of income, and are not subject to income taxes. The Company reviews the financial strength of the insurance carriers prior to the purchase of life insurance policies and no less than annually thereafter. A life insurance policy with any individual carrier is limited to 15% of Tier I capital (as defined for regulatory purposes) and the total cash surrender value of life insurance policies is limited to 25% of Tier I capital.
Premises and Equipment	Premises and Equipment . Premises and equipment are stated at cost less accumulated depreciation. Acquired premises and equipment (through the acquisition of a company or branch acquisition) are stated at their estimated fair values as of the acquisition date less accumulated depreciation that occurred subsequent to the acquisition date. Depreciation and amortization are computed using the straight-line method over the estimated useful lives of the related assets. Leasehold improvements are amortized over the lesser of the term of the respective lease or the estimated life of the improvement. Land is carried at cost. Software costs are stated at cost less accumulated depreciation within other assets on the consolidated statements of condition. Amortization expense is calculated using the straight-line method over the estimated useful lives of the related assets.
OREO	OREO . OREO properties acquired through foreclosure or deed-in-lieu of foreclosure are recorded initially at estimated fair value less estimated costs to sell. Any write-down of the recorded investment in the related loan is charged to the ALL upon transfer to OREO. Upon acquisition of a property, a current appraisal is used or an internal valuation is prepared to substantiate fair value of the property. Any subsequent declines in the fair value of a property are recorded as a valuation allowance on the asset. Any subsequent increases in the fair value of a property are recorded as reductions of the valuation allowance, but not below zero. Upon a sale of an OREO property, any excess of the carrying value over the sale proceeds is recognized as a loss on sale. Any excess of sale proceeds over the carrying value of the OREO property is first applied as a recovery to the valuation allowance, if any, with the remainder being recognized as a gain on sale. Operating expenses, including legal and other direct expenses, and changes in the valuation allowance relating to foreclosed assets are included in other non-interest expense on the consolidated statements of income.
Mortgage Servicing	Mortgage Banking . Residential real estate mortgages are originated by the Company both for its portfolio and for sale into the secondary market. The transfer of these financial assets is accounted for as a sale when control over the asset has been surrendered. Control is deemed to be surrendered when (i) the asset has been isolated from the Company, (ii) the transferee obtains the right (free of conditions that constrain it from taking advantage of that right) to pledge or exchange the transferred asset, and (iii) the Company does not maintain effective control over the transferred asset through an agreement to repurchase them before their maturity. The Company records the gain on sale of the financial asset within mortgage banking income, net on its consolidated statements of income, net of direct and indirect costs incurred to originate the loan. Servicing assets are recognized as separate assets when servicing rights are acquired through the sale of residential mortgage loans with servicing rights retained. Capitalized servicing rights, which are reported in other assets on the consolidated statements of condition, are initially recorded at fair value and are amortized in proportion to, and over the period of, the estimated future servicing of the underlying mortgages (typically, the contractual life of the mortgage). The amortization of mortgage servicing rights is recorded as a reduction of loan servicing fee income within non-interest income on the consolidated statements of income. Servicing assets are evaluated for impairment quarterly based upon the fair value of the rights as compared to amortized cost. Impairment is determined by stratifying rights by predominant characteristics, such as interest rates and terms. Fair value is determined using prices for similar assets with similar characteristics, when available, or based upon discounted cash flows using market-based assumptions. Impairment of the servicing assets is recognized through a valuation allowance to the extent that fair value is less than the capitalized amount. If it is later determined that all or a portion of the impairment no longer exists, a reduction of the allowance may be recorded increasing income, but not below zero. Servicing fee income is recorded for fees earned for servicing loans for investors. The fees are based on a contractual percentage of the outstanding principal or a fixed amount per loan and are recorded as income within non-interest income on the consolidated statements of income when earned.
Other Borrowed Funds	. Short-term borrowings consist of borrowings maturing within one year of the consolidated statement of condition date, while long-term borrowings consist of borrowings maturing in one or more years. The Company's borrowings include retail and wholesale repurchase agreements, FHLBB overnight and short-term borrowings, federal funds purchased, a capital lease, and line of credit advances. The Company is required to post collateral for certain borrowings, for which it, generally, posts loans and/or investment securities as collateral.
Income Taxes	Income Taxes . Income taxes are accounted for using the asset and liability method. Under this method, deferred tax assets and liabilities are recognized for the future tax implications attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases. If current information suggests that it is not more likely than not that the Company will be able to realize the deferred tax assets, a valuation allowance is established. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income in the period that includes the enactment date. The Company assesses quarterly whether or not a valuation allowance on its deferred tax assets is necessary. If it is more likely than not that the Company will not be able to realize the benefit of the deferred tax assets then a valuation allowance is established on the deferred tax asset not expected to be realized. At December 31, 2017 and 2016, the Company did not carry a valuation allowance on its deferred tax assets.
Earnings per Share	EPS . Basic EPS excludes dilution and is computed by dividing net income applicable to common stock by the weighted-average number of common shares outstanding for the period. Diluted EPS reflects the potential dilution that could occur if certain securities or other contracts to issue common stock (such as stock options) were exercised or converted into additional common shares that would then share in the earnings of the Company. Diluted EPS is computed by dividing net income applicable to common stock by the weighted-average number of common shares outstanding for the period, plus an incremental number of common-equivalent shares computed using the treasury stock method. Unvested share-based payment awards which include the right to receive non-forfeitable dividends are considered to participate with common stock in undistributed earnings for purposes of computing EPS. Restricted share grants and management stock purchase grants are considered participating securities for this purpose. Accordingly, the Company is required to calculate basic and diluted EPS using the two-class method. The calculation of EPS using the two-class method (i) excludes any dividends paid or owed on participating securities and any undistributed earnings considered to be attributable to participating securities from the numerator and (ii) excludes the dilutive impact of the participating securities from the denominator.
Postretirement and Supplemental Retirement Plans	Postretirement Plans . The Company sponsors various retirement plans for current and former employees, including a SERP for certain officers of the Company and a postretirement health care and life insurance plan to certain eligible retired employees. The SERP and postretirement benefit plans are unfunded and have no plan assets, and the Company has recorded a liability on its consolidated statements of condition. For the SERP, benefit obligations are estimated using the projected unit credit method. Under this method, each participant's benefits are attributed to years of service, taking into consideration future salary increases and the SERP's benefit allocation formula. Thus, the estimated total pension to which each participant is expected to become entitled to at retirement is broken down into units, each associated with a year of past or future credited service. For the SERP, an individual's estimated attributed benefit for valuation purposes related to a particular separation date is the benefit described under the SERP based on credited service as of the measurement date, but determined using the projected salary that would be used in the calculation estimate of the benefit on the expected separation date.
Stock-Based Compensation	Stock-Based Compensation . The fair value of restricted stock awards, restricted stock units and stock options is determined on the grant date. For restricted stock awards and units, compensation is recognized ratably over the requisite service period equal to the fair value of the award. For stock option awards, the fair value is determined using the Black-Scholes option-pricing model. Compensation expense for stock option awards is recognized ratably over the requisite service period equal to the fair value of the award. For performance-based share awards, the Company estimates the degree to which performance conditions will be met to determine the number of shares that will vest and the related compensation expense. Compensation expense is adjusted in the period such estimates change.
Off-Balance Sheet Credit Related Financial Instruments	Off-Balance Sheet Credit Related Financial Instruments . In the ordinary course of business, the Company enters into commitments to extend credit, including commercial letters of credit and standby letters of credit. Such financial instruments are recorded as loans when they are funded.
Derivative Financial Instruments Designated as Hedges	Derivative Financial Instruments Designated as Hedges . The Company recognizes all derivatives in the consolidated statements of condition at fair value. On the date the Company enters into the derivative contract, the Company designates the derivative as a hedge of either a forecasted transaction or the variability of cash flows to be received or paid related to a recognized asset or liability (“cash flow hedge”), a hedge of the fair value of a recognized asset or liability or of an unrecognized firm commitment (“fair value hedge”), or a held for trading instrument (“trading instrument”). The Company formally documents relationships between hedging instruments and hedged items, as well as its risk management objectives and strategy for undertaking various hedge transactions. The Company also assesses, both at the hedge’s inception and on an ongoing basis, whether the derivatives that are used in hedging transactions are effective in offsetting changes in cash flows or fair values of hedged items. Changes in fair value of a derivative that is effective and that qualifies as a cash flow hedge are recorded in OCI and are reclassified into earnings when the forecasted transaction or related cash flows affect earnings. Changes in fair value of a derivative that qualifies as a fair value hedge and the change in fair value of the hedged item are both recorded in earnings and offset each other when the transaction is effective. Those derivatives that are classified as trading instruments are recorded at fair value with changes in fair value recorded in earnings. The Company discontinues hedge accounting when it determines that the derivative is no longer effective in offsetting changes in the cash flows of the hedged item, that it is unlikely that the forecasted transaction will occur, or that the designation of the derivative as a hedging instrument is no longer appropriate.
Segment Reporting	Segment Reporting . The Company, through its bank subsidiary, provides a broad range of financial services to individuals and companies primarily in Maine. These services include lending, checking, savings and time deposits, cash management, brokerage, wealth management and trust services. Substantially all of the Company's revenues, profits, and assets are derived by the Bank from banking products and services. The Company did not have any reportable segments for the year ended December 31, 2017, 2016 or 2015.
Recent Accounting Pronouncements	Recent Accounting Pronouncements . (The following recently issued accounting pronouncements are presented in chronological order of required adoption date for the Company. Should the Company have early adopted a recently issued accounting pronouncement it has been presented in the year of adoption.) In February 2018, the FASB issued ASU No. 2018-02, Income Statement-Reporting Comprehensive Income (Topic 220): Reclassification of Certain Tax Effects from Accumulate Other Comprehensive Income ("ASU 2018-02"). ASU 2018-02 was issued to allow a reclassification from AOCI to retained earnings for stranded tax effects resulting from the Tax Act. The Company made a policy election to adopt ASU 2018-02 effective for its year ended December 31, 2017 consolidated financial statements, the period in which the effects of the change in the U.S. federal corporate income tax due to the Tax Act were recognized. The adoption of ASU 2018-02 resulted in a $3.5 million income reclassification from AOCI to retained earnings within its consolidated statements of condition and consolidated statements of shareholders' equity for the year ended December 31, 2017. In August 2015, the FASB issued ASU No. 2015-14, Revenue from Contracts with Customers (Topic 606) : Deferral of the Effective Date ("ASU 2015-14"). ASU 2015-14 was issued to defer the effective date of ASU 2014-09, Revenue from Contracts with Customers (Topic 606) ("ASU 2014-09"), for all entities by one year. ASU 2014-09 was issued to clarify the principles for recognizing revenue and to develop a common revenue standard. ASU 2014-09 is effective for annual reporting periods beginning after December 15, 2017, including interim reporting periods within that reporting period. The Company adopted ASU 2014-09 effective January 1, 2018 using the modified-retrospective transition method. As part of its assessment, the Company concluded that the following material revenue streams were within the scope of ASU 2014-09: (i) service charges on deposit accounts; (ii) debit card interchange income; and (iii) income from fiduciary services and brokerage fees. Through the Company's assessment, it was determined that the impact of the adoption of ASU 2014-09 is not material to its financial statements. There will be no cumulative-effect adjustment to beginning shareholders' equity under the modified-retrospective transition method within the Company's first quarter 2018 financial reporting on Form 10-Q as there was no change in revenue recognition upon adoption of ASU 2014-09. In January 2016, the FASB issued ASU No. 2016-01, Income Statement - Financial Instruments - Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Liabilities ("ASU 2016-01"). ASU 2016-01 was issued to enhance the reporting model for financial instruments to provide the users of financial statements with more useful information for decisions. The Company adopted ASU 2016-01 effective January 1, 2018. Upon adoption, the Company will recognize unrealized gains and losses on its equity securities directly through the Company's consolidated statements of income, instead of reporting unrealized gains and losses on equity investments designated as AFS within AOCI. A cumulative-effect adjustment will occur to the Company's beginning shareholders' equity within its first quarter 2018 financial reporting on Form 10-Q to reclassify the unrealized gain reporting within AOCI at December 31, 2017 to retained earnings. The reclassification is immaterial to the Company's financial statements. In addition, ASU 2016-01 also requires companies to utilize an "exit price" fair value methodology for purposes of disclosing the fair value of financial assets and liabilities not measured and reported at fair value on a recurring or non-recurring basis. The Company does not anticipate ASU 2016-01 will materially impact the Company's financial disclosures. In March 2017, the FASB issued ASU No. 2017-07, Compensation-Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost ("ASU 2017-07"). ASU 2017-07 was issued to improve the presentation of net periodic pension cost and net periodic postretirement by companies to disaggregate the service cost component from the other components of net benefit cost, as well as provide other guidance to improve consistency, transparency and usefulness. Upon adoption in the first quarter of 2018, the Company will present and disclose the service cost component in the salaries and employee benefits line on its consolidated statements of income and the other components of net periodic benefit cost within other expenses on its consolidated statements of income. Upon adoption, the change in presentation will be applied retrospectively. The Company will use the amounts previously disclosed within its prior year financial statements as a practical expedient for retrospective presentation within its consolidated statements of income. The other provisions of ASU 2017-07 are not applicable to the Company. ASU 2017-07 will not have a material impact to its financial statements upon adoption. In May 2017, the FASB issued ASU No. 2017-09, Compensation-Stock Compensation (Topic 718): Scope of Modification Accounting ("ASU 2017-09") . ASU 2017-09 was issued to provide clarification about which changes to the terms or conditions of a share-based payment award would require application of modification accounting in Topic 718. ASU 2017-09 is effective for annual periods, and interim periods within those annual periods, beginning after December 15, 2017. Early adoption is permitted, including adoption in an interim period. ASU 2017-09 is to be applied prospectively effective as of the adoption date. During the year ended December 31, 2017, the Company elected to early adopt ASU 2017-09, effective as of January 1, 2017. The Company has not had any modifications to its share-based awards for the year ended December 31, 2017. In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842) ("ASU 2016-02"). ASU 2016-02 was issued to increase transparency and comparability among organizations by recognizing lease assets and liabilities (including operating leases) on the balance sheet and disclosing key information about leasing arrangements. Current lease accounting does not require the inclusion of operating leases in the balance sheet. ASU 2016-02 is effective for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years, early application is permitted. The Company will adopt under a modified-retrospective approach. Upon adoption, ASU 2016-02 will increase the Company's total assets and liabilities on its consolidated statements of condition as its operating leases will be accounted for as a right-of-use asset and a lease liability; however, the Company does not anticipate that upon adoption the ASU will have a material effect on its consolidated financial statements. The Company continues to evaluate the impact of adoption of this standard. In March 2017, the FASB issued ASU No. 2017-08, Receivables - Nonrefundable Fees and Other Costs (Subtopic 310-20): Premium Amortization on Purchased Callable Debt Securities ("ASU 2017-08"). ASU 2017-08 was issued to shorten the amortization period for certain callable debt securities purchased and carried at a premium, by requiring the premium to be amortized to the earliest call date of the debt security. ASU 2017-08 is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2018. Early adoption is permitted, including adoption in an interim period. The Company will adopt on a modified retrospective basis with any necessary adjustments to retained earnings as a cumulative-effect adjustment. While the Company continues to assess the impact of ASU 2017-08, it does not expect the ASU will have a material impact to its financial statements upon adoption. In August 2017, the FASB issued ASU No. 2017-12, Derivatives and Hedging (Topic 815): Targeted Improvements to Accounting for Hedging Activities ("ASU 2017-12") . ASU 2017-12 was issued to make certain specific improvements to hedge accounting to better align hedge accounting with risk management activities, eliminate the separate measurement and recording of hedge ineffectiveness, improve presentation and disclosure, and other simplifications. ASU 2017-12 is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2018. Early adoption is permitted, including adoption in an interim period. All transition requirements and elections are to be applied to existing hedging relationships upon adoption. While the Company continues to assess the impact of ASU 2017-12, it does not believe it will have a material impact on the Company's consolidated financial statements upon adoption. In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments ("ASU 2016-13"). ASU 2016-13 was issued to require timelier recording of credit losses on loans and other financial instruments held by financial institutions and other organizations. ASU 2016-13 is effective for annual periods beginning after December 15, 2019, including interim periods within those fiscal years, for public companies. Early adoption is permitted for annual periods beginning after December 15, 2018, including interim periods within that fiscal year. The Company will adopt the guidance under a modified-retrospective approach, whereby a cumulative-effect adjustment will be made to retained earnings upon adoption. The Company will use a prospective transition approach for debt securities for which an OTTI had been recognized before the effective date, as applicable. While the Company continues to prepare for the adoption of ASU 2016-13 on January 1, 2020, it recognizes the changes to its consolidated financial statements upon adoption are imminent as the ASU requires: • A change in the Company's assessment of its ALL and allowance on unused commitments as it will transition from an incurred loss model to an expected loss model, which may result in an increase in the ALL upon adoption and may negatively impact the Company and Bank's regulatory capital ratios. • May reduce the carrying value of the Company's HTM investment securities as it will require an allowance on the expected losses over the life of these securities to be recorded upon adoption. • Changes to the considerations when assessing AFS debt securities for OTTI, including (i) no longer considering the amount of time a security has been in an unrealized loss position and (ii) no longer considering the historical and implied volatility of a security and recoveries or declines in the fair value after the balance sheet date, as well as the presentation of OTTI as an allowance rather than a permanent write-down of the debt security. • Changes to the disclosure requirements to reflect the transition from an incurred loss methodology to an expected credit loss methodology, as well as certain disclosures of credit quality indicators in relation to the amortized cost of financing receivables disaggregated by year of origination (or vintage). The Company continues to assess the overall impact to its financial statements, and, at this time, it does not have an estimated impact to its financial statements. In January 2017, the FASB issued ASU No. 2017-04, Intangibles - Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment ("ASU 2017-04"). ASU 2017-04 was issued to reduce the cost and complexity of the goodwill impairment test. To simplify the subsequent measurement of goodwill, step two of the goodwill impairment test was eliminated. Instead, in accordance with ASU 2017-04, a Company will recognize an impairment of goodwill should the carrying value of a reporting unit exceed its fair value (i.e. step one). ASU 2017-04 will be effective for the Company on January 1, 2020 and will be applied prospectively.
ALL	ALL. The ALL is established through provisions for loan losses charged to income. Losses on loans, including impaired loans, are charged to the ALL when all or a portion of a loan is deemed to be uncollectible. Recoveries of loans previously charged off are credited to the ALL when realized. In determining the appropriate level of ALL, the Company uses a methodology to systematically measure the amount of estimated loan loss exposure inherent in the loan portfolio. The methodology includes three elements: (1) identification of loss allocations for certain specific loans, (2) loss allocation factors for certain loan types based on credit risk and loss experience, and (3) general loss allocations for other qualitative and environmental factors. The allocations for specific loans is determined based on loans that have a principal balance of $500,000 or more that are classified as substandard or doubtful and are on non-accrual status. Effective January 1, 2017, the Company's internal policy for assessing specific loans for impairment was increased from $250,000 to $500,000. The qualitative factors for assessing a loan individually for impairment in accordance with the Company's internal policy were unchanged, and continue to require the loan to be classified as substandard or doubtful and on non-accrual status. For such loans that are also classified as impaired, an allowance is established when the discounted expected future cash flows (or collateral value or observable market price) of the impaired loan is lower than the recorded investment of that loan. Loans that do not meet the above criteria are separated into risk pools by portfolio segment and risk ratings. The Company then evaluates each risk pool collectively for impairment through loss allocation factors. The Company uses a risk rating system for certain loan segments to determine the credit quality of these loan pools and applies the related loss allocation factors. In assessing the risk rating of a particular loan, the Company considers, among other factors, the obligor’s debt capacity, financial condition, the level of the obligor’s earnings, the amount and sources of repayment, the performance with respect to loan terms, the adequacy of collateral, the level and nature of contingent liabilities, management strength, and the industry in which the obligor operates. These factors are based on an evaluation of historical information, as well as subjective assessment and interpretation of current conditions. Emphasizing one factor over another, or considering additional factors that may be relevant in determining the risk rating of a particular loan but which are not currently an explicit part of the Company's methodology, could impact the risk rating assigned to that loan. The Company at least annually, and more frequently as deemed prudent by management, reassesses and revises the loss allocation factors used in the assignment of loss exposure to appropriately reflect the analysis of loss experience. Portfolios of more homogeneous populations of loans including home equity and consumer loans are analyzed as groups taking into account delinquency rates and other economic conditions which may affect the ability of borrowers to meet debt service requirements, including interest rates and energy costs. The Company also considers regulatory guidance, historical loss ranges, portfolio composition, and other changes in the portfolio. An additional allocation is determined based on a judgmental process whereby management considers qualitative and quantitative assessments of other environmental factors. Since the methodology is based upon historical experience and trends, as well as management’s judgment, factors may arise that result in different estimations. Significant factors that could give rise to changes in these estimates may include, but are not limited to, changes in economic conditions in the Company’s market areas, concentration of risk, declines in local property values, and regulatory guidance. Loans past due 30 days or more are considered delinquent. In general, secured loans that are delinquent for 90 consecutive days are placed on non-accrual status, and are subject to impairment and/or loss assessment in accordance with established internal policy. In general, unsecured loans that are delinquent for 90 consecutive days are charged off. In cases where a borrower experiences financial difficulties and the Company makes certain concessionary modifications to contractual terms, the loan is classified as a TDR. Modifications may include adjustments to interest rates, extensions of maturity, and other actions intended to minimize economic loss and avoid foreclosure or repossession of collateral. An allowance is established on a loan classified as a TDR if the present value of expected future cash flows (or, alternatively, the observable market price of the loan or the fair value of the collateral if the loan is collateral-dependent) is less than the recorded investment of the loan. Non-accrual loans that are restructured as TDRs remain on non-accrual status for a period of at least six months to demonstrate that the borrower can meet the restructured terms. If the restructured loan is on accrual status prior to being modified, it is reviewed to determine if the modified loan should remain on accrual status. If the borrower’s ability to meet the revised payment schedule is not reasonably assured, the loan is classified as a non-accrual loan. Loans classified as TDRs remain classified as such for the life of the loan, except in limited circumstances, when it is determined that the borrower is performing under the modified terms and the restructuring agreement specified an interest rate greater than or equal to an acceptable market rate for a comparable new loan at the time of the restructuring.

Mergers and Acquisitions (Table

Mergers and Acquisitions (Tables)	12 Months Ended
	Dec. 31, 2017
Business Combinations [Abstract]
Acquisition Related Costs	The Company incurred acquisition-related costs for the periods indicated as detailed below: For The Year Ended December 31, 2017 2016 2015 Salaries and employee benefits (1) $ — $ 8 $ 3,240 Furniture, equipment and data processing — 279 1,531 Net occupancy — 439 1,237 Consulting and professional fees (2) — 80 2,453 Other expenses (3) — 60 1,954 Total merger and acquisition costs $ — $ 866 $ 10,415 (1) Includes the costs associated with pre-existing change-in-control agreements in place at the time of the Merger and employee termination costs, including severance. (2) Includes the cost of a negotiated non-compete arrangement entered into in connection with the Merger of $400,000 in 2015. (3) Other expenses include marketing and insurance costs, certain contract termination costs, various printing and mailing costs associated with various customer communications, and travel-related costs associated with the integration of the two companies in 2015. The following table summarizes the estimated fair value of the assets acquired and liabilities assumed as of the date of the acquisition: As Acquired Fair Value Adjustments (Previously Reported) Measurement-Period Adjustments As Recorded at Acquisition Consideration Paid: Cash $ 26,125 Company common stock (4,124,643 shares at $26.32 per share) 108,561 Non-qualified stock options 1,990 Total consideration paid 136,676 Recognized identifiable assets acquired and liabilities assumed, at fair value: Loans and loans held for sale $ 639,390 $ (11,497 ) $ 137 628,030 Cash and due from banks 86,042 — — 86,042 Investments 39,716 26 — 39,742 Deferred tax assets 26,293 (1,177 ) 666 25,782 Premises and equipment 16,851 7,093 — 23,944 OREO 2,530 (1,801 ) — 729 Core deposit intangible assets — 6,608 — 6,608 Other assets 5,421 (170 ) 157 5,408 Deposits and borrowings 719,640 1,546 — 721,186 Other liabilities 8,512 (198 ) — 8,314 Total identified assets acquired and liabilities assumed, at fair value $ 88,091 $ (2,266 ) $ 960 86,785 Goodwill $ 49,891

Securities (Tables)

Securities (Tables)	12 Months Ended
	Dec. 31, 2017
Investments, Debt and Equity Securities [Abstract]
Summary of Amortized Costs and Estimated Fair Values of Available-For-Sale Securities	The following tables summarize the amortized costs and estimated fair values of AFS and HTM securities, as of the dates indicated: Amortized Cost Unrealized Gains Unrealized Losses Fair Value December 31, 2017: AFS Securities: Obligations of states and political subdivisions $ 7,232 $ 103 $ — $ 7,335 Mortgage-backed securities issued or guaranteed by U.S. government-sponsored enterprises 510,176 597 (7,471 ) 503,302 Collateralized mortgage obligations issued or guaranteed by U.S. government-sponsored enterprises 279,575 14 (6,790 ) 272,799 Subordinated corporate bonds 5,484 173 — 5,657 Total AFS debt securities 802,467 887 (14,261 ) 789,093 Equity securities 554 252 — 806 Total AFS securities $ 803,021 $ 1,139 $ (14,261 ) $ 789,899 HTM Securities: Obligations of states and political subdivisions $ 94,073 $ 1,077 $ (237 ) $ 94,913 Total HTM securities $ 94,073 $ 1,077 $ (237 ) $ 94,913 December 31, 2016: AFS Securities: Obligations of states and political subdivisions $ 8,848 $ 153 $ — $ 9,001 Mortgage-backed securities issued or guaranteed by U.S. government-sponsored enterprises 485,222 2,515 (7,115 ) 480,622 Collateralized mortgage obligations issued or guaranteed by U.S. government-sponsored enterprises 289,046 265 (5,421 ) 283,890 Subordinated corporate bonds 5,481 132 — 5,613 Total AFS debt securities 788,597 3,065 (12,536 ) 779,126 Equity securities 632 109 — 741 Total AFS securities $ 789,229 $ 3,174 $ (12,536 ) $ 779,867 HTM Securities: Obligations of states and political subdivisions $ 94,609 $ 618 $ (631 ) $ 94,596 Total HTM securities $ 94,609 $ 618 $ (631 ) $ 94,596
Unrealized Gross Losses and Estimated Fair Values of Investment Securities by Length of Time that Individual Securities in Each Category in Continuous Loss Position	The following table presents the estimated fair values and gross unrealized losses of investment securities that were in a continuous loss position at December 31, 2017 and 2016 , by length of time that individual securities in each category have been in a continuous loss position: Less Than 12 Months 12 Months or More Total Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses December 31, 2017: AFS Securities: Mortgage-backed securities issued or guaranteed by U.S. government-sponsored enterprises $ 221,466 $ (2,393 ) $ 233,971 $ (5,078 ) $ 455,437 $ (7,471 ) Collateralized mortgage obligations issued or guaranteed by U.S. government-sponsored enterprises 102,612 (696 ) 164,389 (6,094 ) 267,001 (6,790 ) Total AFS securities $ 324,078 $ (3,089 ) $ 398,360 $ (11,172 ) $ 722,438 $ (14,261 ) HTM Securities: Obligations of states and political subdivisions $ 9,317 $ (57 ) $ 9,436 $ (180 ) $ 18,753 $ (237 ) Total HTM securities $ 9,317 $ (57 ) $ 9,436 $ (180 ) $ 18,753 $ (237 ) December 31, 2016: AFS Securities: Mortgage-backed securities issued or guaranteed by U.S. government-sponsored enterprises $ 348,579 $ (5,780 ) $ 29,496 $ (1,335 ) $ 378,075 $ (7,115 ) Collateralized mortgage obligations issued or guaranteed by U.S. government-sponsored enterprises 163,412 (2,906 ) 74,212 (2,515 ) 237,624 (5,421 ) Total AFS securities $ 511,991 $ (8,686 ) $ 103,708 $ (3,850 ) $ 615,699 $ (12,536 ) HTM Securities: Obligations of states and political subdivisions $ 42,805 $ (631 ) $ — $ — $ 42,805 $ (631 ) Total HTM securities $ 42,805 $ (631 ) $ — $ — $ 42,805 $ (631 )
Company's Sales of Securities	The following table details the Company’s sales of AFS investment securities, the gross realized gains and losses, and OTTI of securities: For The Year Ended December 31, 2017 2016 2015 Proceeds from sales of securities $ 20,366 $ 28,850 $ 12,426 Gross realized gains 869 125 221 Gross realized losses (14 ) (74 ) (217 ) Previously recorded OTTI — — 204
Amortized Cost and Estimated Fair Values of Debt Securities by Contractual Maturity	The amortized cost and estimated fair values of securities by contractual maturity at December 31, 2017 are shown below. Expected maturities will differ from contractual maturities because borrowers may have the right to call or prepay obligations with or without call or prepayment penalties. Amortized Cost Fair Value AFS Securities Due in one year or less $ 4,986 $ 4,983 Due after one year through five years 104,294 103,572 Due after five years through ten years 212,809 209,663 Due after ten years 480,378 470,875 $ 802,467 $ 789,093 HTM Securities Due in one year or less $ 751 $ 751 Due after one year through five years 4,705 4,721 Due after five years through ten years 10,110 10,192 Due after ten years 78,507 79,249 $ 94,073 $ 94,913

Loans and Allowance for Loan 34

Loans and Allowance for Loan Losses (Tables)	12 Months Ended
	Dec. 31, 2017
Receivables [Abstract]
Composition of Loan Portfolio, Excluding Residential Loans Held for Sale	The composition of the Company’s loan portfolio, excluding residential loans held for sale, at December 31, 2017 and 2016 was as follows: December 31, 2017 2016 Residential real estate loans $ 858,369 $ 802,494 Commercial real estate loans 1,164,023 1,050,780 Commercial loans 373,400 333,639 Home equity loans 323,378 329,907 Consumer loans 18,149 17,332 HPFC 45,120 60,412 Total loans $ 2,782,439 $ 2,594,564
Schedule of Loan Balances for Each Portfolio Segment	The loan balances for each portfolio segment presented above are net of their respective unamortized fair value mark discount on acquired loans and net of unamortized loan origination costs totaling: December 31, 2017 2016 Net unamortized fair value mark discount on acquired loans $ 6,207 $ 8,810 Net unamortized loan origination costs (963 ) (66 ) Total $ 5,244 $ 8,744
Schedule of Loans Made to Related Parties	Loans, including any unused lines of credit, to related parties were as follows: December 31, 2017 2016 Balance at beginning of year $ 15,942 $ 16,628 Loans made/advanced and additions 230 434 Repayments and reductions (3,032 ) (1,120 ) Balance at end of year $ 13,140 $ 15,942
Activity in Allowance for Loan Losses by Portfolio Segment	The following table presents the activity in the ALL and select loan information by portfolio segment for the year ended December 31, 2017 , 2016 , and 2015 : Residential Real Estate Commercial Real Estate Commercial Home Equity Consumer HPFC Unallocated Total For The Year Ended December 31, 2017: ALL: Beginning balance $ 4,160 $ 12,154 $ 3,755 $ 2,194 $ 181 $ 672 $ — $ 23,116 Loans charged off (482 ) (124 ) (1,014 ) (434 ) (124 ) (290 ) — (2,468 ) Recoveries 30 141 301 2 17 6 — 497 Provision (credit) (1) 1,378 (308 ) 1,129 605 159 63 — 3,026 Ending balance $ 5,086 $ 11,863 $ 4,171 $ 2,367 $ 233 $ 451 $ — $ 24,171 ALL balance attributable loans: Individually evaluated for impairment $ 568 $ 1,441 $ — $ — $ — $ — $ — $ 2,009 Collectively evaluated for impairment 4,518 10,422 4,171 2,367 233 451 — 22,162 Total ending ALL $ 5,086 $ 11,863 $ 4,171 $ 2,367 $ 233 $ 451 $ — $ 24,171 Loans: Individually evaluated for impairment $ 5,171 $ 6,199 $ 1,791 $ 429 $ — $ — $ — $ 13,590 Collectively evaluated for impairment 853,198 1,157,824 371,609 322,949 18,149 45,120 — 2,768,849 Total loan balances $ 858,369 $ 1,164,023 $ 373,400 $ 323,378 $ 18,149 $ 45,120 $ — $ 2,782,439 For The Year Ended December 31, 2016: ALL: Beginning balance $ 4,545 $ 10,432 $ 3,241 $ 2,731 $ 193 $ 24 $ — $ 21,166 Loans charged off (356 ) (315 ) (2,218 ) (308 ) (101 ) (507 ) — (3,805 ) Recoveries 95 50 332 2 7 — — 486 Provision (credit) (1) (124 ) 1,987 2,400 (231 ) 82 1,155 — 5,269 Ending balance $ 4,160 $ 12,154 $ 3,755 $ 2,194 $ 181 $ 672 $ — $ 23,116 ALL balance attributable loans: Individually evaluated for impairment $ 483 $ 1,373 $ — $ 86 $ — $ 65 $ — $ 2,007 Collectively evaluated for impairment 3,677 10,781 3,755 2,108 181 607 — 21,109 Total ending ALL $ 4,160 $ 12,154 $ 3,755 $ 2,194 $ 181 $ 672 $ — $ 23,116 Loans: Individually evaluated for impairment $ 4,348 $ 13,317 $ 2,028 $ 457 $ 7 $ 97 $ — $ 20,254 Collectively evaluated for impairment 798,146 1,037,463 331,611 329,450 17,325 60,315 — 2,574,310 Total loan balances $ 802,494 $ 1,050,780 $ 333,639 $ 329,907 $ 17,332 $ 60,412 $ — $ 2,594,564 Residential Real Estate Commercial Real Estate Commercial Home Equity Consumer HPFC Unallocated Total For The Year Ended December 31, 2015: ALL: Beginning balance $ 4,899 $ 7,951 $ 3,354 $ 2,247 $ 281 $ — $ 2,384 $ 21,116 Loans charged off (801 ) (481 ) (655 ) (525 ) (154 ) — — (2,616 ) Recoveries 55 74 389 188 22 — — 728 Provision (credit) (1) 392 2,888 153 821 44 24 (2,384 ) 1,938 Ending balance $ 4,545 $ 10,432 $ 3,241 $ 2,731 $ 193 $ 24 $ — $ 21,166 ALL balance attributable loans: Individually evaluated for impairment $ 544 $ 644 $ 92 $ 89 $ — $ — $ — $ 1,369 Collectively evaluated for impairment 4,001 9,788 3,149 2,642 193 24 — 19,797 Total ending ALL $ 4,545 $ 10,432 $ 3,241 $ 2,731 $ 193 $ 24 $ — $ 21,166 Loans: Individually evaluated for impairment $ 6,026 $ 4,610 $ 3,937 $ 588 $ 74 $ — $ — $ 15,235 Collectively evaluated for impairment 814,591 923,341 293,784 348,046 17,879 77,330 — 2,474,971 Total loan balances $ 820,617 $ 927,951 $ 297,721 $ 348,634 $ 17,953 $ 77,330 $ — $ 2,490,206 (1) The provision (credit) for loan losses excludes any impact for the change in the reserve for unfunded commitments, which represents management's estimate of the amount required to reflect the probable inherent losses on outstanding letters of credit and unused lines of credit. The reserve for unfunded commitments is presented within accrued interest and other liabilities on the consolidated statements of condition. At December 31, 2017 , 2016 , and 2015 , the reserve for unfunded commitments was $20,000 , $11,000 and $22,000 , respectively.
Schedule of Provision for Credit Losses	The following table reconciles the year ended December 31, 2017 , 2016 , and 2015 provision for loan losses to the provision for credit losses as presented on the consolidated statement of income: For the Year Ended December 31, 2017 2016 2015 Provision for loan losses $ 3,026 $ 5,269 $ 1,938 Change in reserve for unfunded commitments 9 (11 ) (2 ) Provision for credit losses $ 3,035 $ 5,258 $ 1,936
Credit Risk Exposure Indicators by Portfolio Segment	The following table summarizes credit risk exposure indicators by portfolio segment as of the following dates: Residential Real Estate Commercial Real Estate Commercial Home Equity Consumer HPFC Total December 31, 2017: Pass (Grades 1 – 6) $ 846,394 $ 1,130,235 $ 354,904 $ — $ — $ 43,049 $ 2,374,582 Performing — — — 321,727 18,149 — 339,876 Special Mention (Grade 7) 922 9,154 12,517 — — 191 22,784 Substandard (Grade 8) 11,053 24,634 5,979 — — 1,880 43,546 Non-performing — — — 1,651 — — 1,651 Total $ 858,369 $ 1,164,023 $ 373,400 $ 323,378 $ 18,149 $ 45,120 $ 2,782,439 December 31, 2016: Pass (Grades 1 – 6) $ 789,554 $ 1,003,386 $ 321,148 $ — $ — $ 58,943 $ 2,173,031 Performing — — — 328,287 17,328 — 345,615 Special Mention (Grade 7) 2,387 5,724 5,598 — — 257 13,966 Substandard (Grade 8) 10,553 41,670 5,437 — — 1,212 58,872 Doubtful (Grade 9) — — 1,456 — — — 1,456 Non-performing — — — 1,620 4 — 1,624 Total $ 802,494 $ 1,050,780 $ 333,639 $ 329,907 $ 17,332 $ 60,412 $ 2,594,564
Loan Aging Analysis by Portfolio Segment (Including Loans Past Due Over Ninety Days and Non Accrual Loans) and Summary of Non Accrual Loans, Which Include Troubled Debt Restructured Loans, and Loans Past Due Over Ninety Days and Accruing	The following is a loan aging analysis by portfolio segment (including loans past due over 90 days and non-accrual loans) and a summary of non-accrual loans, which include TDRs, and loans past due over 90 days and accruing as of the following dates: 30 – 59 Days Past Due 60 – 89 Days Past Due Greater Than 90 Days Total Past Due Current Total Loans Outstanding Loans > 90 Days Past Due and Accruing Non-Accrual Loans December 31, 2017: Residential real estate $ 3,871 $ 1,585 $ 4,021 $ 9,477 $ 848,892 $ 858,369 $ — $ 4,979 Commercial real estate 849 323 5,528 6,700 1,157,323 1,164,023 — 5,642 Commercial 329 359 1,535 2,223 371,177 373,400 — 2,000 Home equity 1,046 173 1,329 2,548 320,830 323,378 — 1,650 Consumer 57 10 — 67 18,082 18,149 — — HPFC 139 1,372 419 1,930 43,190 45,120 — 1,043 Total $ 6,291 $ 3,822 $ 12,832 $ 22,945 $ 2,759,494 $ 2,782,439 $ — $ 15,314 December 31, 2016: Residential real estate $ 1,783 $ 924 $ 2,904 $ 5,611 $ 796,883 $ 802,494 $ — $ 3,945 Commercial real estate 855 223 12,625 13,703 1,037,077 1,050,780 — 12,849 Commercial 633 218 1,675 2,526 331,113 333,639 — 2,088 Home equity 892 134 1,321 2,347 327,560 329,907 — 1,620 Consumer 38 — 4 42 17,290 17,332 — 4 HPFC 438 688 110 1,236 59,176 60,412 — 207 Total $ 4,639 $ 2,187 $ 18,639 $ 25,465 $ 2,569,099 $ 2,594,564 $ — $ 20,713
Troubled Debt Restructuring and Specific Reserve Related to TDRs	The following is a summary of TDRs, by portfolio segment, and the associated specific reserve included within the ALL as of December 31: Number of Contracts Recorded Investment Specific Reserve 2017 2016 2017 2016 2017 2016 Residential real estate 24 21 $ 3,604 $ 3,221 $ 452 $ 483 Commercial real estate 3 3 976 1,008 16 — Commercial 7 10 1,345 1,502 — — Consumer and home equity 2 1 307 16 — — Total 36 35 $ 6,232 $ 5,747 $ 468 $ 483
Summary of All Troubled Debt Restructuring Loans (Accruing and Non Accruing) by Portfolio Segment	The following represents loan modifications that occurred for the year ended December 31, 2017 , 2016 and 2015 that qualify as TDRs and the type of loan modification made by portfolio segment at December 31: Number of Contracts Pre-Modification Outstanding Recorded Investment Post-Modification Outstanding Recorded Investment Specific Reserve 2017 2016 2015 2017 2016 2015 2017 2016 2015 2017 2016 2015 Residential real estate: Maturity concession 2 — — $ 298 $ — $ — $ 298 $ — $ — $ 15 $ — $ — Court ordered — — 1 — — 74 — — 78 — — 27 Interest rate concession 1 — — 134 — — 145 — — — — — Interest rate and maturity concession 1 — — 148 — — 156 — — 30 — — Commercial: Maturity concession — 6 — — 2,973 — — 2,973 — — 1,400 — Home equity: Interest rate and maturity concession 1 — — 315 — — 315 — — — — — Total 5 6 1 $ 895 $ 2,973 $ 74 $ 914 $ 2,973 $ 78 $ 45 $ 1,400 $ 27
Summary of Impaired Loan Balances and Associated Allowance by Portfolio Segment	The following is a summary of impaired loan balances and the associated allowance by portfolio segment as of and for the year ended December 31, 2017 , 2016 and 2015 : Recorded Investment Unpaid Principal Balance Related Allowance Average Recorded Investment Interest Income Recognized December 31, 2017: With related allowance recorded: Residential real estate $ 3,858 $ 3,858 $ 568 $ 3,177 $ 131 Commercial real estate 5,422 5,422 1,441 8,900 22 Commercial — — — 31 — Home equity — — — 125 — Consumer — — — — — HPFC — — — 24 — Ending balance 9,280 9,280 2,009 12,257 153 Without related allowance recorded: Residential real estate 1,313 1,673 — 1,345 15 Commercial real estate 777 1,084 — 1,132 29 Commercial 1,791 2,964 — 1,920 10 Home equity 429 495 — 310 8 Consumer — — — 2 — HPFC — — — — — Ending balance 4,310 6,216 — 4,709 62 Total impaired loans $ 13,590 $ 15,496 $ 2,009 $ 16,966 $ 215 December 31, 2016: With related allowance recorded: Residential real estate $ 3,019 $ 3,019 $ 483 $ 3,088 $ 106 Commercial real estate 11,443 11,443 1,373 5,165 — Commercial — — — 762 — Home equity 299 299 86 305 — Consumer — — — — — HPFC 97 97 65 98 — Ending balance 14,858 14,858 2,007 9,418 106 Without related allowance recorded: Residential real estate 1,329 1,800 — 2,057 9 Commercial real estate 1,874 2,369 — 2,214 51 Commercial 2,028 3,209 — 2,507 16 Home equity 158 368 — 180 — Consumer 7 10 — 12 — HPFC — — — — — Ending balance 5,396 7,756 — 6,970 76 Total impaired loans $ 20,254 $ 22,614 $ 2,007 $ 16,388 $ 182 Recorded Investment Unpaid Principal Balance Related Allowance Average Recorded Investment Interest Income Recognized December 31, 2015: With related allowance recorded: Residential real estate $ 3,191 $ 3,191 $ 544 $ 6,064 $ 112 Commercial real estate 1,825 1,857 644 1,753 — Commercial 156 156 92 945 2 Home equity 303 303 89 900 — Consumer — — — 195 — HPFC — — — — — Ending balance 5,475 5,507 1,369 9,857 114 Without related allowance recorded: Residential real estate 2,835 4,353 — 2,175 8 Commercial real estate 2,785 3,426 — 2,719 65 Commercial 3,781 4,325 — 1,412 17 Home equity 285 688 — 369 — Consumer 74 150 — 20 — HPFC — — — — — Ending balance 9,760 12,942 — 6,695 90 Total impaired loans $ 15,235 $ 18,449 $ 1,369 $ 16,552 $ 204

Goodwill (Tables)

Goodwill (Tables)	12 Months Ended
	Dec. 31, 2017
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Goodwill	The changes in goodwill for the year ended December 31, 2017 and 2016 for each reporting unit are shown in the table below: Banking Financial Services Total Balance as of January 1, 2016: Goodwill $ 91,753 $ 7,474 $ 99,227 Accumulated impairment losses — (3,570 ) (3,570 ) Reported goodwill 91,753 3,904 95,657 Measurement-period adjustment (Note 2) (960 ) — (960 ) Balance as of December 31, 2016: Goodwill 90,793 7,474 98,267 Accumulated impairment losses — (3,570 ) (3,570 ) Reported goodwill $ 90,793 $ 3,904 $ 94,697 Balance as of January 1 and December 31, 2017: Goodwill $ 90,793 $ 7,474 $ 98,267 Accumulated impairment losses — (3,570 ) (3,570 ) Reported goodwill $ 90,793 $ 3,904 $ 94,697

Other Intangible Assets (Tables

Other Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2017
Other Intangible Assets [Abstract]
Schedule of Finite-Lived Intangible Assets	The gross carrying amount and accumulated amortization of other intangible assets were as follows at the periods indicated: December 31, 2017 2016 Gross Carrying Amount Accumulated Amortization Net Carrying Amount Gross Carrying Amount Accumulated Amortization Net Carrying Amount Core deposit intangible $ 23,908 $ (18,953 ) $ 4,955 $ 23,908 $ (17,220 ) $ 6,688 Trust relationship intangible 753 (753 ) — 753 (677 ) 76 Total $ 24,661 $ (19,706 ) $ 4,955 $ 24,661 $ (17,897 ) $ 6,764
Schedule of Expected Amortization Schedule	The following table reflects the expected amortization schedule for other intangible assets over the period of estimated economic benefit (assuming no additional intangible assets are created or impaired): Core Deposit Intangible 2018 $ 725 2019 705 2020 682 2021 655 2022 625 Thereafter 1,563 Total $ 4,955

Premises and Equipment (Tables)

Premises and Equipment (Tables)	12 Months Ended
	Dec. 31, 2017
Property, Plant and Equipment [Abstract]
Schedule of Premises and Equipment	Depreciation and amortization expense for the periods indicated were as follows: For The Year Ended December 31, Fixed Asset Type Income Statement Line Item 2017 2016 2015 Equipment and data Furniture, equipment and data processing $ 1,874 $ 1,942 $ 1,620 Premises Net occupancy costs 1,643 1,757 1,140 Software Furniture, equipment and data processing 244 275 337 Equipment, data and premises Merger and acquisition costs — 452 517 Total $ 3,761 $ 4,426 $ 3,614 Details of premises and equipment, at cost, for the periods indicated, were as follows: 2017 2016 Land and land improvements $ 2,985 $ 3,012 Buildings and leasehold improvements 37,054 36,958 Furniture, fixtures and equipment 36,053 34,043 Total cost 76,092 74,013 Accumulated depreciation and amortization (34,201 ) (31,140 ) Net premises and equipment $ 41,891 $ 42,873
Schedule of Capital and Operating Lease Obligations	At December 31, 2017 , under current operating and capital lease contracts, the Company had the following schedule of future minimum lease payments: Operating Capital 2018 $ 1,429 $ 126 2019 1,394 126 2020 888 126 2021 671 130 2022 484 131 Thereafter 1,531 425 Total minimum lease payments $ 6,397 1,064 Less: amount representing interest (1) 273 Present value of net minimum lease payments (2) $ 791 (1) Amount necessary to reduce net minimum lease payments to present value calculated at the Company's incremental borrowing rate at lease inception. (2) Reflects the liability reported within short- and long-term borrowings on the consolidated statements of condition. At December 31, 2017 and 2016 , the capital lease liability was $791,000 and $858,000 , respectively.

Mortgage Banking (Tables)

Mortgage Banking (Tables)	12 Months Ended
	Dec. 31, 2017
Transfers and Servicing [Abstract]
Schedule of Mortgage Servicing Rights Capitalized and Amortized	The following summarizes servicing assets capitalized and amortized, along with the activity in the related valuation allowance: As of and For The Year Ended December 31, 2017 2016 2015 Servicing Assets: Balance at beginning of year $ 1,210 $ 2,161 $ 493 Capitalized servicing right fees upon sale (1) 22 9 294 Acquired in connection with acquisition of SBM, at fair value — — 1,608 Amortization charged against mortgage servicing fee income (1) (430 ) (734 ) (231 ) Valuation adjustment 223 (226 ) (3 ) Balance at end of year $ 1,025 $ 1,210 $ 2,161 Valuation Allowance: Balance at beginning of year $ (230 ) $ (4 ) $ (1 ) (Increase) decrease in impairment reserve (1) 223 (226 ) (3 ) Balance at end of year $ (7 ) $ (230 ) $ (4 ) Fair value, beginning of year $ 1,701 $ 2,947 $ 1,447 Fair value, end of year $ 1,766 $ 1,701 $ 2,947 (1) Reported within mortgage banking income, net on the Company's consolidated statements of income.

Deposits (Tables)

Deposits (Tables)	12 Months Ended
	Dec. 31, 2017
Deposits [Abstract]
Schedule Of Deposit Maturities	The following is a summary of scheduled maturities of CDs as of December 31, 2017 : Retail Brokered Total 2018 $ 239,936 $ — $ 239,936 2019 110,867 — 110,867 2020 62,944 7,000 69,944 2021 32,208 — 32,208 2022 19,816 — 19,816 Thereafter 9,239 — 9,239 Total $ 475,010 $ 7,000 $ 482,010

Borrowings (Tables)

Borrowings (Tables)	12 Months Ended
	Dec. 31, 2017
Debt Disclosure [Abstract]
Summary of Short term and Long term Borrowings and Subordinated Debentures	The following table summarizes the Company's short term and long term borrowings, and subordinated debentures as presented on the consolidated statements of condition for the periods indicated: December 31, 2017 Contractual Maturity December 31, 2016 Outstanding Balance Weighted Average Rate 2018 2019 2020 2021 2022 Thereafter Outstanding Balance Weighted Average Rate Short-Term Borrowings: FHLBB borrowings $ 250,000 $ 250,000 $ — $ — $ — $ — $ — $ 210,000 Customer repurchase agreements 244,646 244,646 — — — — — 225,605 FHLBB and correspondent bank overnight borrowings 47,150 47,150 — — — — — 89,450 Wholesale repurchase agreements — — — — — — — 5,007 Capital lease obligation 71 71 — — — — — 67 Total short-term borrowings $ 541,867 1.10 % $ 541,867 $ — $ — $ — $ — $ — $ 530,129 0.74 % Long-Term Borrowings: FHLBB borrowings $ 10,000 1.87 % $ — $ — $ 10,000 $ — $ — $ — $ 10,000 1.87 % Capital lease obligation 720 4.18 % — 76 81 90 98 375 791 4.31 % Total long-term borrowings $ 10,720 2.03 % $ — $ 76 $ 10,081 $ 90 $ 98 $ 375 $ 10,791 2.05 % Subordinated Debentures: Subordinated debentures (1) $ 14,580 5.50 % $ — $ — $ — $ — $ — $ 14,580 $ 14,526 5.50 % CCTA 36,083 5.48 % — — — — — 36,083 36,083 5.50 % UBCT 8,248 6.75 % — — — — — 8,248 8,146 6.85 % Total subordinated debentures $ 58,911 5.66 % $ — $ — $ — $ — $ — $ 58,911 $ 58,755 5.69 % (1) Presented net of debt issuance costs of $420,000 and $474,000 at December 31, 2017 and 2016, respectively.
Schedule of Federal Home Loan Bank Advances	At December 31, 2017, the terms of the Company's outstanding FHLBB borrowings were as follows: Balance Sheet Classification Outstanding Balance Maturity Date Interest Rate Range Next Call Date Call Amount Short-Term Borrowings $ 200,000 January 2018 1.45% - 1.63% N/A $ — Short-Term Borrowings $ 50,000 February 2018 1.54% N/A $ — Long-Term Borrowings $ 10,000 April 2020 1.87% N/A $ —

Repurchase Agreements (Tables)

Repurchase Agreements (Tables)	12 Months Ended
	Dec. 31, 2017
Banking and Thrift [Abstract]
Schedule of Underlying Assets of Repurchase Agreements when Amount of Repurchase Agreements Exceeds 10 Percent of Assets	The tables below sets forth information regarding the Company’s repurchase agreements accounted for as secured borrowings and types of collateral at December 31, 2017 and 2016 : Remaining Contractual Maturity of the Agreements Overnight and Continuous Up to 30 Days 30 - 90 Days Greater than 90 Days Total December 31, 2017 Customer Repurchase Agreements: Obligations of states and political subdivisions $ 630 $ — $ — $ — $ 630 Mortgage-backed securities issued or guaranteed by U.S. government-sponsored enterprises 98,460 — — — 98,460 Collateralized mortgage obligations issued or guaranteed by U.S. government-sponsored enterprises 145,556 — — — 145,556 Total Customer Repurchase Agreements 244,646 — — — 244,646 Total Repurchase Agreements (1) $ 244,646 $ — $ — $ — $ 244,646 December 31, 2016 Customer Repurchase Agreements: Mortgage-backed securities issued or guaranteed by U.S. government-sponsored enterprises $ 117,784 $ — $ — $ — $ 117,784 Collateralized mortgage obligations issued or guaranteed by U.S. government-sponsored enterprises 107,821 — — — 107,821 Total Customer Repurchase Agreements 225,605 — — — 225,605 Wholesale Repurchase Agreements: Mortgage-backed securities issued or guaranteed by U.S. government-sponsored enterprises — — 3,715 — 3,715 Collateralized mortgage obligations issued or guaranteed by U.S. government-sponsored enterprises — — 1,292 — 1,292 Total Wholesale Repurchase Agreements — — 5,007 — 5,007 Total Repurchase Agreements (1) $ 225,605 $ — $ 5,007 $ — $ 230,612 (1) Presented within short-term borrowings on the consolidated statements of condition.

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Schedule of Income Tax Expense	The current and deferred components of income tax expense on the consolidated statements of income were as follows: For The Year Ended December 31, 2017 2016 2015 Current: Federal $ 14,529 $ 17,854 $ 7,956 State 1,289 930 71 15,818 18,784 8,027 Deferred: Change in federal corporate income tax rate (1) 14,263 — — Federal 4,117 (1,258 ) 1,356 State (320 ) (54 ) 524 18,060 (1,312 ) 1,880 Income tax expense $ 33,878 $ 17,472 $ 9,907
Reconciliation of Expected Income Tax Benefit Computed Using Federal Statutory Income Tax Rate	The income tax expense differs from the amount computed by applying the statutory federal income tax rate as a result of the following: For The Year Ended December 31, 2017 2016 2015 Computed tax expense $ 21,824 $ 20,139 $ 10,801 Increase (reduction) in income taxes resulting from: Change in federal corporate income tax rate 14,263 — — Tax exempt income (1,291 ) (1,312 ) (1,092 ) Income from life insurance (829 ) (908 ) (588 ) State taxes, net of federal benefit 630 565 373 Share-based awards (1) (390 ) (701 ) — Low income housing credits (366 ) (376 ) (359 ) Non-deductible acquisition-related costs — — 467 Other 37 65 305 Income tax expense $ 33,878 $ 17,472 $ 9,907 Income before income taxes $ 62,354 $ 57,539 $ 30,859 Effective tax rate 54.3 % 30.4 % 32.1 %
Schedule of Deferred Tax Assets and Deferred Tax Liabilities	Temporary differences between the financial statements carrying amounts and the tax bases of assets and liabilities gave rise to the following deferred tax assets and liabilities: December 31, 2017 (1) 2016 (2) Asset Liability Asset Liability Net operating loss and tax credit carryforward $ 12,078 $ — $ 20,977 $ — Allowance for loan losses 5,201 — 8,094 — Pension and other benefits 3,363 — 5,141 — Net unrealized losses on AFS securities 2,821 — 3,227 — Net unrealized losses on derivative instruments 1,623 — 3,066 — Deferred compensation and benefits 1,199 — 1,791 — Net unrealized losses on postretirement plans 1,092 — 1,147 — Purchase accounting and deposit premium 461 — 1,430 — Depreciation — (2,857 ) — (4,520 ) Deferred loan origination fees — (1,510 ) — (2,046 ) Other — (695 ) 956 — 27,838 (5,062 ) 45,829 (6,566 ) Valuation allowance on deferred tax assets — — Net deferred tax assets $ 22,776 $ 39,263

Shareholders' Equity (Tables)

Shareholders' Equity (Tables)	12 Months Ended
	Dec. 31, 2017
Stockholders' Equity Note [Abstract]
Schedule of Compliance with Regulatory Capital Requirements	The following table presents the Company and Bank's regulatory capital ratios at the periods indicated: December 31, Minimum Regulatory Capital Required for Capital Adequacy plus Capital Conservation Buffer Minimum Regulatory Provision To Be "Well Capitalized" Under Prompt Corrective Action Provisions December 31, Minimum Regulatory Capital Required For Capital Adequacy plus Capital Conservation Buffer Minimum Regulatory Provision To Be "Well Capitalized" Under Prompt Corrective Action Provisions Amount Ratio Amount Ratio Camden National Corporation: Total risk-based capital ratio $ 396,451 14.14 % 9.25 % N/A $ 368,856 14.04 % 8.63 % N/A Tier I risk-based capital ratio 357,261 12.74 % 7.25 % N/A 330,729 12.59 % 6.63 % N/A Common equity Tier I risk-based capital ratio 316,677 11.30 % 5.75 % N/A 296,120 11.27 % 5.13 % N/A Tier I leverage capital ratio 357,261 9.07 % 4.00 % N/A 330,729 8.83 % 4.00 % N/A Camden National Bank: Total risk-based capital ratio $ 369,540 13.18 % 9.25 % 10.00 % $ 340,908 12.92 % 8.63 % 10.00 % Tier I risk-based capital ratio 345,350 12.32 % 7.25 % 8.00 % 317,782 12.05 % 6.63 % 8.00 % Common equity Tier I risk-based capital ratio 345,350 12.32 % 5.75 % 6.50 % 317,782 12.05 % 5.13 % 6.50 % Tier I leverage capital ratio 345,350 8.80 % 4.00 % 5.00 % 317,782 8.54 % 4.00 % 5.00 %

Earnings Per Share (Tables)

Earnings Per Share (Tables)	12 Months Ended
	Dec. 31, 2017
Earnings Per Share [Abstract]
Computation of Basic and Diluted Earnings Per Share	The following is an analysis of basic and diluted EPS, reflecting the application of the two-class method, as described below: For The Year Ended December 31, 2017 2016 2015 Net income $ 28,476 $ 40,067 $ 20,952 Dividends and undistributed earnings allocated to participating securities (1) (118 ) (189 ) (59 ) Net income available to common shareholders $ 28,358 $ 39,878 $ 20,893 Weighted-average common shares outstanding for basic EPS 15,509,665 15,422,160 12,031,294 Dilutive effect of stock-based awards (2) 78,682 82,079 43,285 Weighted-average common and potential common shares for diluted EPS 15,588,347 15,504,239 12,074,579 Earnings per common share: Basic EPS $ 1.83 $ 2.59 $ 1.73 Diluted EPS $ 1.82 $ 2.57 $ 1.73 Awards excluded from the calculation of diluted EPS (3) : Stock options — — 19,875 (1) Represents dividends paid and undistributed earnings allocated to nonvested stock-based awards that contain non-forfeitable rights to dividends. (2) Represents the effect of the assumed exercise of stock options, and vesting of restricted shares and restricted stock units, and issuance of LTIP awards that have met the performance criteria, utilizing the treasury stock method. (3) Represents stock-based awards not included in the computation of potential common shares for purposes of calculating diluted EPS as the exercise prices were greater than the average market price of the Company's common stock, and, therefore, are considered anti-dilutive.

Stock-Based Compensation Plans

Stock-Based Compensation Plans (Tables)	12 Months Ended
	Dec. 31, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Schedule of Option Pricing Assumptions and Estimated Fair Value	The following table presents the option pricing assumptions and the estimated fair value of the options using these assumptions for grants made for the year ended: December 31, 2017 2016 2015 Weighted-average dividend yield — % 3.12 % 3.01 % Weighted-average risk-free interest rate — % 1.52 % 1.50 % Weighted-average expected volatility — % 29.64 % 31.85 % Weighted-average expected life (in years) 0.0 5.3 5.3 Weighted-average fair value of options granted $ — $ 5.17 $ 5.87
Schedule of Stock Option Activity	Stock option activity for the year ended December 31, 2017 was as follows: Number of Options Weighted-Average Exercise Price per Option Weighted-Average Remaining Contractual Term (Years) Aggregate Intrinsic Value Options outstanding at January 1, 2017 58,743 $ 20.38 Granted — — Exercised (11,841 ) 17.50 Forfeited (2,400 ) 26.23 Expired (1,425 ) 23.11 Options outstanding at December 31, 2017 43,077 $ 21.00 3.45 $ 910 Options exercisable at December 31, 2017 39,627 $ 20.58 3.11 $ 854 A summary of the status of the Company’s nonvested stock options as of December 31, 2017 and changes during the year then ended was as follows: Options Weighted-Average Grant Date Fair Value per Option Nonvested at January 1, 2017 9,450 $ 6.59 Granted — — Vested (3,600 ) 7.80 Forfeited (2,400 ) 5.48 Nonvested at December 31, 2017 3,450 $ 6.11
Schedule of Compensation Expense	Compensation expense and the related income tax benefit recognized in connection with the MSPP awards was as follows for the periods indicated: For The Year Ended 2017 2016 2015 Compensation expense $ 97 $ 102 $ 66 Income tax benefit 21 36 23 Fair value of grants vested 91 57 92 Compensation expense and the related income tax benefit recognized in connection with the restricted stock awards was as follows for the periods indicated: For The Year Ended 2017 2016 2015 Compensation expense $ 762 $ 703 $ 327 Income tax benefit 164 246 114 Fair value of grants vested 702 603 341 Compensation expense recognized in connection with the DCRP was presented in the following table: For The Year Ended 2017 2016 2015 Compensation expense $ 97 $ 81 $ 62 Related income tax benefit 21 28 22 Fair value of grants vested 90 75 59 Compensation expense for the LTIP's performance-based awards was presented in the following table: For The Year Ended 2017 2016 2015 Compensation expense (1) $ 370 $ 1,080 $ 330 Related income tax benefit 80 378 116 Fair value of grants vested 843 725 412 Compensation expense and the related income tax benefit recognized in connection with the restricted stock units was as follows for the periods indicated: For The Year Ended 2017 2016 2015 Compensation expense $ 124 $ — $ — Income tax benefit 27 — — Fair value of grants vested — — —
Summary of Nonvested Share Awards Activity	Restricted stock award activity for the year ended December 31, 2017 is as follows: Number of Shares Weighted-Average Grant Date Fair Value per Share Weighted-Average Remaining Contractual Term (Years) Aggregate Intrinsic Value Unrecognized Compensation Nonvested at January 1, 2017 47,518 $ 28.16 Granted 16,185 42.39 Vested (22,553 ) 31.14 Forfeited (4,825 ) 28.93 Nonvested at December 31, 2017 36,325 $ 32.56 2.2 $ 1,530 $ 787 DCRP award activity for the year ended December 31, 2017 was as follows: Number of Deferred Stock Awards Weighted-Average Grant Date Fair Value per Award Weighted-Average Remaining Contractual Term (Years) Aggregate Intrinsic Value Unrecognized Compensation Nonvested at January 1, 2017 14,244 $ 23.65 Granted 2,772 42.66 Vested (2,776 ) 32.50 Forfeited (4,192 ) 25.88 Nonvested at December 31, 2017 10,048 $ 25.52 9.2 $ 423 $ 229 MSPP award activity for the year ended December 31, 2017 was as follows: Number of Shares Weighted-Average Grant Date Fair Value per Share Weighted-Average Remaining Contractual Term (Years) Aggregate Intrinsic Value Unrecognized Compensation Nonvested at January 1, 2017 26,699 $ 7.85 Granted 8,088 13.73 Vested (11,777 ) 7.73 Forfeited (2,791 ) 11.49 Nonvested at December 31, 2017 20,219 $ 9.77 1.0 $ 431 $ 54 LTIP performance-based award activity for the year ended December 31, 2017 was as follows: Number of Shares Weighted-Average Grant Date Fair Value per Share Weighted-Average Remaining Contractual Term (Years) Aggregate Intrinsic Value Unrecognized Compensation Nonvested at January 1, 2017 52,737 $ 27.01 Granted 16,830 41.39 Vested (32,323 ) 26.09 Forfeited (5,621 ) 26.97 Nonvested at December 31, 2017 31,623 $ 35.60 1.7 $ 1,332 $ 291 Restricted stock unit activity for the year ended December 31, 2017 was as follows: Number of Units Weighted-Average Grant Date Fair Value per Unit Weighted-Average Remaining Contractual Term (Years) Aggregate Intrinsic Value Unrecognized Compensation Nonvested at January 1, 2017 — $ — Granted 18,762 43.05 Vested — — Forfeited (1,285 ) 43.11 Nonvested at December 31, 2017 17,477 $ 43.04 4.6 $ 736 $ 620

Employee Benefit Plans (Tables)

Employee Benefit Plans (Tables)	12 Months Ended
	Dec. 31, 2017
Compensation and Retirement Disclosure [Abstract]
Schedule of Changes in Benefit Obligation and Plan Assets	The following table summarizes changes in the benefit obligation and plan assets for (i) SERP and (ii) the other postretirement benefit plan as of December 31, 2017 and 2016 : SERP Other Postretirement Benefits 2017 2016 2017 2016 Benefit obligations: Beginning of year $ 11,523 $ 11,052 $ 3,635 $ 3,447 Service cost 335 308 53 59 Interest cost 452 432 144 151 Actuarial loss 1,955 219 110 143 Benefits paid (475 ) (488 ) (151 ) (165 ) End of year 13,790 11,523 3,791 3,635 Fair value of plan assets: Beginning of year — — — — Employer contributions 475 488 151 165 Benefits paid (475 ) (488 ) (151 ) (165 ) End of year — — — — Unfunded status at end of year (1) $ 13,790 $ 11,523 $ 3,791 $ 3,635 Amounts recognized in AOCI, net of tax: Net actuarial loss $ 3,504 $ 1,791 $ 654 $ 495 Prior service credit — — (170 ) (156 ) Total $ 3,504 $ 1,791 $ 484 $ 339 (1) Presented within other liabilities on the consolidated statements of condition.
Schedule of Net Period Benefit Cost and Other Amounts Recognized in Other Comprehensive Income	The components of net periodic benefit cost and other amounts recognized in OCI, before taxes, were as follows: SERP Other Postretirement Benefits 2017 2016 2015 2017 2016 2015 Net periodic benefit cost: Service cost $ 335 $ 308 $ 307 $ 53 $ 59 $ 62 Interest cost 452 432 424 144 151 117 Recognized net actuarial loss 246 220 218 41 30 24 Amortization of prior service cost (credit) — 7 19 (24 ) (22 ) (22 ) Net periodic benefit cost 1,033 967 968 214 218 181 Changes in funded status recognized in OCI, before taxes: Net actuarial (gain) loss arising during period 1,955 219 (32 ) 110 143 92 Reclassifications to net period benefit cost: Amortization of net unrecognized actuarial loss (246 ) (220 ) (218 ) (41 ) (30 ) (24 ) Amortization of prior service (cost) credit — (7 ) (19 ) 24 22 22 Total recognized in OCI, before taxes 1,709 (8 ) (269 ) 93 135 90 Total recognized in net periodic benefit cost and OCI, before taxes $ 2,742 $ 959 $ 699 $ 307 $ 353 $ 271
Schedule of Assumptions Used in Determining Benefit Obligations and Net Period Benefit Costs	The following assumptions were used in determining benefit obligations and net period benefit costs: SERP Other Postretirement Benefits 2017 2016 2015 2017 2016 2015 Weighted-average assumptions as of end of year: Discount rate for benefit obligation 3.60 % 4.00 % 4.00 % 3.55 % 4.00 % 4.50 % Discount rate for net periodic benefit cost 4.00 % 4.00 % 4.00 % 4.00 % 4.50 % 4.00 % Rate of compensation increase for benefit obligation 5.00 % 4.00 % 4.00 % — — — Rate of compensation increase for net periodic benefit cost 5.00 % 4.00 % 4.00 % — — — Health care cost trend rate assumed for future years — — — 6.50 % 7.00 % 7.00 %
Schedule of Estimated Future Benefit Payments	The expected benefit payments for the next ten years are presented in the following table: SERP Other Postretirement Benefits 2018 473 156 2019 477 168 2020 486 173 2021 536 175 2022 566 187 2023-2027 2,246 1,061

Other Non-Interest Income and47

Other Non-Interest Income and Expenses (Tables)	12 Months Ended
	Dec. 31, 2017
Other Noninterest Expenses [Abstract]
Schedule of Other Non-Interest Expenses	Detail of other income included in the consolidated statements of income is as follows: For The Year Ended December 31, Other income 2017 2016 2015 Customer loan swap fee income (1) $ 1,574 $ 2,104 $ 1,514 Other income 1,545 4,830 2,363 Total $ 3,119 $ 6,934 $ 3,877 (1) Fee income recognized upon completion of customer loan swaps. Refer to Note 18 for further discussion. Detail of other expenses included in the consolidated statements of income is as follows: For The Year Ended December 31, Other expenses 2017 2016 2015 Donations and marketing $ 1,852 $ 1,660 $ 1,841 Employee-related costs (1) 1,710 1,616 1,437 Postage, freight, and courier 1,655 1,754 1,430 Other expenses 5,731 5,657 4,502 Total $ 10,948 $ 10,687 $ 9,210 (1) Employee-related costs include hiring, training, education, meeting and business travel costs.

Commitments, Contingencies an48

Commitments, Contingencies and Derivatives (Tables)	12 Months Ended
	Dec. 31, 2017
Commitments and Contingencies Disclosure [Abstract]
Summary of Contractual and Notional Amounts of Financial Instruments	The following is a summary of the contractual and notional amounts of the Company’s financial instruments: December 31, 2017 2016 Lending-Related Instruments: Loan origination commitments and unadvanced lines of credit: Home equity $ 477,401 $ 454,225 Commercial and commercial real estate 49,482 83,103 Residential 41,368 17,795 Letters of credit 2,848 2,580 Other commitments 523 432 Derivative Financial Instruments: Customer loan swaps $ 703,336 $ 532,526 FHLBB advance interest rate swaps 50,000 50,000 Junior subordinated debt interest rate swaps 43,000 43,000 Fixed-rate mortgage interest rate lock commitments 21,746 15,249 Forward delivery commitments 8,065 15,125
Schedule of Interest Rate Derivatives	Our pipeline of mortgage loans with fixed-rate interest rate lock commitments were as follows for the periods indicated: December 31, 2017 2016 Balance Sheet Location Notional Fair Value Notional Fair Value Fixed-rate mortgage interest rate locks Other assets $ 19,886 $ 307 $ 12,310 $ 202 Fixed-rate mortgage interest rate locks Accrued interest and other liabilities 1,860 (22 ) 2,939 (15 ) Total $ 21,746 $ 285 $ 15,249 $ 187 The following table presents the total positions, notional and fair value of the Bank's customer loans swaps with its commercial customers and the corresponding interest rate swap agreements with counterparty for the periods indicated: December 31, 2017 2016 Balance Sheet Location Number of Positions Notional Fair Value Number of Positions Notional Fair Value Receive fixed, pay variable Other assets / (accrued interest and other liabilities) 42 $ 226,884 $ (5,036 ) 50 $ 266,263 $ (1,945 ) Receive fixed, pay variable Other assets / (accrued interest and other liabilities) 23 124,784 1,799 — — — Pay fixed, receive variable Other assets / (accrued interest and other liabilities) 65 351,668 3,237 50 266,263 1,945 Total 130 $ 703,336 $ — 100 $ 532,526 $ —
Summary of Contractual and Notional Amounts of Company's Financial Instruments	The Company's forward delivery commitments on loans held for sale was as follows for the periods indicated: December 31, 2017 2016 Balance Sheet Location Notional Fair Value Notional Fair Value Forward delivery commitments ("best-effort") Other assets $ 6,692 $ 158 $ 14,250 $ 587 Forward delivery commitments ("best-effort") Accrued interest and other liabilities 1,373 (16 ) 875 (309 ) Total $ 8,065 $ 142 $ 15,125 $ 278 The details of the junior subordinated debt interest rate swaps for the periods indicated were as follows: December 31, 2017 2016 Notional Amount Trade Date Maturity Date Variable Index Received Fixed Rate Paid Fair Value (1) Fair Value (1) $ 10,000 3/18/2009 6/30/2021 3-Month USD LIBOR 5.09% $ (527 ) $ (806 ) 10,000 7/8/2009 6/30/2029 3-Month USD LIBOR 5.84% (2,133 ) (2,321 ) 10,000 5/6/2010 6/30/2030 3-Month USD LIBOR 5.71% (2,129 ) (2,290 ) 5,000 3/14/2011 3/30/2031 3-Month USD LIBOR 4.35% (1,137 ) (1,211 ) 8,000 5/4/2011 7/7/2031 3-Month USD LIBOR 4.14% (1,645 ) (1,744 ) $ 43,000 $ (7,571 ) $ (8,372 ) (1) Presented within accrued interest and other liabilities on the consolidated statements of condition. The details of the FHLBB advance interest rate swaps for the periods indicated were as follows: December 31, 2017 2016 Notional Trade Maturity Date Variable Index Fixed Rate Fair Value (1) Fair Value (2) $ 25,000 2/25/2015 2/25/2018 1-Month USD LIBOR 1.54% $ 20 $ (152 ) 25,000 2/25/2015 2/25/2019 1-Month USD LIBOR 1.74% 1 (237 ) $ 50,000 $ 21 $ (389 ) (1) Presented within other assets on the consolidated statements of condition. (2) Presented within accrued interest and other liabilities on the consolidated statements of condition.
Schedule of Derivative Instruments, Effect on Other Comprehensive Income (Loss)	The table below presents the effect of the Company’s derivative financial instruments included in OCI and current earnings for the periods indicated: For The Year Ended 2017 2016 2015 Derivatives designated as cash flow hedges Effective portion of unrealized losses recognized within AOCI during the period, net of tax $ (248 ) $ (637 ) $ (1,533 ) Net reclassification adjustment for effective portion of cash flow hedges included in interest expense, gross (1) $ 1,592 $ 2,026 $ 1,695 (1) Reclassified into the consolidated statements of income within interest expense.

Fair Value (Tables)

Fair Value (Tables)	12 Months Ended
	Dec. 31, 2017
Fair Value Disclosures [Abstract]
Summary of Financial Assets and Liabilities Measured at Fair Value on Recurring Basis	The following table summarizes financial assets and financial liabilities measured at fair value on a recurring basis as of December 31, 2017 and 2016 , segregated by the level of the valuation inputs within the fair value hierarchy utilized to measure fair value: Fair Value Readily Available Market Prices (Level 1) Observable Market Data (Level 2) Company Determined Fair Value (Level 3) December 31, 2017 Financial assets: Loans held for sale $ 8,103 $ — $ 8,103 $ — AFS securities: Obligations of states and political subdivisions 7,335 — 7,335 — Mortgage-backed securities issued or guaranteed by U.S. government-sponsored enterprises 503,302 — 503,302 — Collateralized mortgage obligations issued or guaranteed by U.S. government-sponsored enterprises 272,799 — 272,799 — Subordinated corporate bonds 5,657 — 5,657 — Equity securities 806 — 806 — Customer loan swaps 5,036 — 5,036 — Fixed-rate mortgage interest rate lock commitments 307 — 307 — Forward delivery commitments 158 — 158 — FHLBB advance interest rate swaps 21 — 21 — Financial liabilities: Junior subordinated debt interest rate swaps 7,571 — 7,571 — Customer loan swaps 5,036 — 5,036 — Fixed-rate mortgage interest rate lock commitments 22 — 22 — Forward delivery commitments 16 — 16 — December 31, 2016 Financial assets: Loans held for sale $ 14,836 $ — $ 14,836 $ — AFS securities: Obligations of states and political subdivisions 9,001 — 9,001 — Mortgage-backed securities issued or guaranteed by U.S. government-sponsored enterprises 480,622 — 480,622 — Collateralized mortgage obligations issued or guaranteed by U.S. government-sponsored enterprises 283,890 — 283,890 — Subordinated corporate bonds 5,613 — 5,613 — Equity securities 741 — 741 — Customer loan swaps 1,945 — 1,945 — Fixed-rate mortgage interest rate lock commitments 202 — 202 — Forward delivery commitments 587 — 587 — Financial liabilities: Junior subordinated debt interest rate swaps 8,372 — 8,372 — FHLBB advance interest rate swaps 389 — 389 — Customer loan swaps 1,945 — 1,945 — Fixed-rate mortgage interest rate lock commitments 15 — 15 — Forward delivery commitments 309 — 309 —
Summary of Assets Measured at Fair Value on Non Recurring Basis	The table below highlights financial and non-financial assets measured and recorded at fair value on a non-recurring basis as of December 31, 2017 and 2016 : Fair Value Readily Available Market Prices (Level 1) Observable Market Data (Level 2) Company Determined Fair Value (Level 3) December 31, 2017 Financial assets: Collateral-dependent impaired loans $ 3,696 $ — $ — $ 3,696 Servicing assets (1) — — — — Non-financial assets: OREO 130 — — 130 December 31, 2016 Financial assets: Collateral-dependent impaired loans $ 500 $ — $ — $ 500 Servicing assets (1) 1,090 — — 1,090 Non-financial assets: OREO 922 — — 922 (1) Represents mortgage serving assets deemed to be impaired and a valuation allowance was established to carry at fair value at December 31, 2017 and 2016 .
Valuation Methodology and Unobservable Inputs for Level Three Assets Measured at Fair Value on Non Recurring Basis	The following table presents the valuation methodology and unobservable inputs for Level 3 assets measured at fair value on a non-recurring basis at December 31, 2017 and 2016 : Fair Value Valuation Methodology Unobservable input Discount Range (Weighted-Average) December 31, 2017 Collateral-dependent impaired loans: Partially charged-off $ 86 Market approach appraisal of collateral Management adjustment of appraisal 0 - 50% (18%) Estimated selling costs 0 - 10% (6%) Specifically reserved 3,610 Market approach appraisal of collateral Management adjustment of appraisal 0% (0%) Estimated selling costs 10% (10%) OREO 130 Market approach appraisal of collateral Management adjustment of appraisal 20% (20%) Estimated selling costs 10% (10%) December 31, 2016 Collateral-dependent impaired loans: Partially charged-off $ 166 Market approach appraisal of collateral Management adjustment of appraisal 0% (0%) Estimated selling costs 0 - 10% (5%) Specifically reserved 334 Market approach appraisal of collateral Management adjustment of appraisal 0 - 50% (13%) Estimated selling costs 10% (10%) OREO 922 Market approach appraisal of collateral Management adjustment of appraisal 0 - 73% (7%) Estimated selling costs 10% (10%)
Carrying Amounts and Estimated Fair Value for Financial Instrument Assets and Liabilities	The following table presents the carrying amounts and estimated fair value for financial instrument assets and liabilities at December 31, 2017 : Carrying Amount Fair Value Readily Available Market Prices (Level 1) Observable Market Prices (Level 2) Company Determined Market Prices (Level 3) Financial assets: Cash and due from banks $ 102,971 $ 102,971 $ 102,971 $ — $ — AFS securities 789,899 789,899 — 789,899 — HTM securities 94,073 94,913 — 94,913 — Loans held for sale 8,103 8,103 — 8,103 — Residential real estate loans (1) 853,283 853,056 — — 853,056 Commercial real estate loans (1) 1,152,160 1,115,618 — — 1,115,618 Commercial loans (1)(2) 413,898 401,902 — — 401,902 Home equity loans (1) 321,011 318,230 — — 318,230 Consumer loans (1) 17,916 17,335 — — 17,335 Servicing assets 1,025 1,766 — 1,766 — Interest receivable 9,595 9,595 — 9,595 — Customer loan swaps 5,036 5,036 — 5,036 — Fixed-rate mortgage interest rate lock commitments 307 307 — 307 — Forward delivery commitments 158 158 — 158 — FHLBB advance interest rate swaps 21 21 — 21 — Financial liabilities: Deposits $ 3,000,491 $ 2,995,269 $ — $ 2,995,269 $ — Short-term borrowings 541,867 541,683 — 541,683 — Long-term borrowings 10,720 10,699 — 10,699 — Subordinated debentures 58,911 44,333 — 44,333 — Interest payable 564 564 — 564 — Junior subordinated debt interest rate swaps 7,571 7,571 — 7,571 — Customer loan swaps 5,036 5,036 — 5,036 — Fixed-rate mortgage interest rate lock commitments 22 22 — 22 — Forward delivery commitments 16 16 — 16 — (1) The presented carrying amount is net of the allocated ALL. (2) Includes the HPFC loan portfolio. The following table presents the carrying amounts and estimated fair value for financial instrument assets and liabilities at December 31, 2016 : Carrying Amount Fair Value Readily Available Market Prices (Level 1) Observable Market Prices (Level 2) Company Determined Market Prices (Level 3) Financial assets: Cash and due from banks $ 87,707 $ 87,707 $ 87,707 $ — $ — AFS securities 779,867 779,867 — 779,867 — HTM securities 94,609 94,596 — 94,596 — Loans held for sale 14,836 14,836 — 14,836 — Residential real estate loans (1) 798,334 800,122 — — 800,122 Commercial real estate loans (1) 1,038,626 1,006,249 — — 1,006,249 Commercial loans (1)(2) 389,624 391,493 — — 391,493 Home equity loans (1) 327,713 327,292 — — 327,292 Consumer loans (1) 17,151 16,845 — — 16,845 Servicing assets 1,210 1,701 — 1,701 — Interest receivable 8,654 8,654 — 8,654 — Customer loan swaps 1,945 1,945 — 1,945 — Fixed-rate mortgage interest rate lock commitments 202 202 — 202 — Forward delivery commitments 587 587 — 587 — Financial liabilities: Deposits $ 2,828,529 $ 2,826,484 $ — $ 2,826,484 $ — Short-term borrowings 530,129 530,435 — 530,435 — Long-term borrowings 10,791 10,836 — 10,836 — Subordinated debentures 58,755 41,660 — 41,660 — Interest payable 534 534 — 534 — Junior subordinated debt interest rate swaps 8,372 8,372 — 8,372 — FHLBB advance interest rate swaps 389 389 — 389 — Customer loan swaps 1,945 1,945 — 1,945 — Fixed-rate mortgage interest rate lock commitments 15 15 — 15 — Forward delivery commitments 309 309 — 309 — (1) The presented carrying amount is net of the allocated ALL. (2) Includes the HPFC loan portfolio.

Parent Company Financial Stat50

Parent Company Financial Statements (Tables)	12 Months Ended
	Dec. 31, 2017
Condensed Financial Information of Parent Company Only Disclosure [Abstract]
Condensed Statements of Condition	Following are the condensed statements of condition, income and cash flows for the Company's parent company: STATEMENTS OF CONDITION December 31, 2017 2016 ASSETS Cash $ 29,365 $ 29,905 Investment in subsidiary 444,235 429,100 Receivable from subsidiary 107 107 Other assets 14,806 12,420 Total assets $ 488,513 $ 471,532 LIABILITIES AND SHAREHOLDERS’ EQUITY Subordinated debentures $ 58,911 $ 58,755 Due to subsidiary 17 37 Other liabilities 26,172 21,193 Shareholders’ equity 403,413 391,547 Total liabilities and shareholders’ equity $ 488,513 $ 471,532
Condensed Statements of Income	STATEMENTS OF INCOME For The Year Ended December 31, 2017 2016 2015 Operating Income Dividend income from subsidiary $ 16,800 $ 16,000 $ 39,200 Other income (loss) 145 239 (18 ) Total operating income 16,945 16,239 39,182 Operating Expenses Interest on borrowings 3,408 3,415 2,734 Fees to Bank 160 160 160 Other operating expenses 592 748 469 Total operating expenses 4,160 4,323 3,363 Income before equity in undistributed earnings of subsidiaries and income taxes 12,785 11,916 35,819 Equity in undistributed income (losses) of subsidiaries 17,405 26,773 (15,999 ) Income before income taxes 30,190 38,689 19,820 Income tax (expense) benefit (1,714 ) 1,378 1,132 Net Income $ 28,476 $ 40,067 $ 20,952
Condensed Statements of Cash Flows	STATEMENTS OF CASH FLOWS For The Year Ended December 31, 2017 2016 2015 Operating Activities Net income $ 28,476 $ 40,067 $ 20,952 Adjustments to reconcile net income to net cash provided by operating activities: Equity in undistributed (income) losses of subsidiaries (17,405 ) (26,655 ) 4,573 Gain on sale of investment securities (32 ) (4 ) — (Increase) decrease in receivable from subsidiaries — 1,819 (1,901 ) (Increase) decrease in other assets (1,930 ) 1,213 (2,175 ) Increase (decrease) in due to subsidiaries (20 ) (1,179 ) 1,216 Increase (decrease) in other liabilities 3,721 (2,519 ) 320 Net cash provided by operating activities 12,810 12,742 22,985 Investing Activities Acquisition of SBM, net of cash acquired — — (25,319 ) Proceeds from sale of investment securities 110 84 — Net cash provided by (used in) investing activities 110 84 (25,319 ) Financing Activities Issuance of subordinated debt, net of issuance costs — — 14,464 Exercise of stock options and issuance of restricted stock, net of repurchase for tax withholdings and tax benefit (606 ) 894 753 Capital contribution from subsidiaries 1,469 1,997 836 Equity issuance costs — — (612 ) Cash dividends paid on common stock and cash in-lieu paid for fractional shares due to stock split (14,323 ) (12,393 ) (9,785 ) Net cash provided by (used in) financing activities (13,460 ) (9,502 ) 5,656 Net (decrease) increase in cash (540 ) 3,324 3,322 Cash at beginning of year 29,905 26,581 23,259 Cash at end of year $ 29,365 $ 29,905 $ 26,581

Quarterly Results of Operatio51

Quarterly Results of Operations (Unaudited) (Tables)	12 Months Ended
	Dec. 31, 2017
Quarterly Financial Information Disclosure [Abstract]
Schedule of Quarterly Results of Operations	The following table presents a summary of the quarterly results of operations for the year ended: December 31, 2017 2016 First Quarter Second Quarter Third Quarter Fourth Quarter (1) First Quarter Second Quarter Third Quarter Fourth Quarter Interest income $ 32,414 $ 33,940 $ 34,710 $ 35,040 $ 31,981 $ 32,775 $ 32,594 $ 32,276 Interest expense 4,559 5,314 5,550 5,381 4,029 4,271 4,222 4,032 Net interest income 27,855 28,626 29,160 29,659 27,952 28,504 28,372 28,244 Provision for credit losses 579 1,401 817 238 872 2,852 1,279 255 Non-interest income 8,572 9,888 10,299 9,840 7,917 10,552 11,001 10,151 Non-interest expense 21,428 22,158 21,825 23,099 22,909 22,330 22,149 22,508 Income before income taxes 14,420 14,955 16,817 16,162 12,088 13,874 15,945 15,632 Income tax expense 4,344 4,721 5,478 19,335 3,442 4,258 5,042 4,730 Net income (loss) $ 10,076 $ 10,234 $ 11,339 $ (3,173 ) $ 8,646 $ 9,616 $ 10,903 $ 10,902 Per common share: Basic $ 0.65 $ 0.66 $ 0.72 $ (0.20 ) $ 0.56 $ 0.62 $ 0.70 $ 0.70 Diluted $ 0.64 $ 0.66 $ 0.72 $ (0.20 ) $ 0.56 $ 0.62 $ 0.70 $ 0.70 (1) In the fourth quarter of 2017, the Company recognized $14.3 million of additional income tax expense upon the revaluation of its deferred tax assets and liabilities upon enactment of the Tax Act on December 22, 2017, which lowered the federal corporate tax rate from 35.0% to 21.0%, effective January 1, 2018. The impact to fourth quarter 2017 basic and diluted EPS was $0.91 per share.

Business and Summary of Signi52

Business and Summary of Significant Accounting Policies (Details)	9 Months Ended	12 Months Ended
	Sep. 30, 2016	Dec. 31, 2017USD ($)reporting_unit_level	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)	Feb. 28, 2018USD ($)
Accounting Policy [Line Items]
Trading Securities		$ 0	$ 0
Equity Method Investment, Ownership Percentage		100.00%
Loans Held-for-sale		$ 8,103,000	14,836,000
Financing Receivable, Individually Evaluated for Impairment		$ 13,590,000	20,254,000	$ 15,235,000
Number of Reporting Unit Levels | reporting_unit_level		2
Goodwill impairment			0	0
BOLI single carrier percentage of Tier I capital		15.00%
BOLI CSV percentage of Tier I Capital		25.00%
HTM securities		$ 94,073,000	94,609,000
AFS securities		$ 789,899,000	779,867,000
Stockholders' Equity Note, Stock Split, Conversion Ratio	1.5	1.5
Minimum [Member]
Accounting Policy [Line Items]
Financing Receivable, Individually Evaluated for Impairment		$ 500,000	250,000
Finite-lived intangible asset, useful life (years)		5 years
Maximum [Member]
Accounting Policy [Line Items]
Finite-lived intangible asset, useful life (years)		10 years
Residential real estate
Accounting Policy [Line Items]
Term to maturity (years)		30 years
Financing Receivable, Individually Evaluated for Impairment		$ 5,171,000	$ 4,348,000	$ 6,026,000
Accumulated Other Comprehensive Income (Loss) | Subsequent Event [Member] | Accounting Standards Update 2018-02 [Member]
Accounting Policy [Line Items]
Reclassification adjustment					$ (3,500,000)
Retained Earnings [Member] | Subsequent Event [Member] | Accounting Standards Update 2018-02 [Member]
Accounting Policy [Line Items]
Reclassification adjustment					$ 3,500,000

Mergers and Acquisitions (Detai

Mergers and Acquisitions (Details)	Oct. 16, 2015USD ($)$ / sharesshares	Dec. 31, 2017USD ($)shares	Dec. 31, 2016USD ($)shares	Dec. 31, 2015USD ($)	Sep. 14, 2016$ / shares	Oct. 15, 2015
Business Acquisition [Line Items]
Equity interest issued		$ 0	$ 0	$ 110,551,000
Share Price | $ / shares					$ 31.75
Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested, Number of Shares | shares		3,450	9,450
Merger and acquisition costs		$ 0	$ 866,000	10,415,000
Goodwill		$ 94,697,000	94,697,000	95,657,000
Number of companies in integration		2
Payments of Stock Issuance Costs		$ 0	$ 0	$ 612,000
SBM Financial, Inc. [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net	$ 86,785,000
Business acquisition, percentage of voting interest acquired	100.00%					80.00%
Business Acquisition, Cash Consideration, Per Share Amount | $ / shares	$ 206
Business Acquisition, Stock for Stock Consideration, Conversion Ratio	8.132
Total consideration paid	$ 136,676,000
Cash	$ 26,125,000
Business Acquisition, Equity Interest Issued or Issuable, Number of Shares | shares	4,124,643
Equity interest issued	$ 108,561,000
Share Price | $ / shares	$ 26.32
Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested, Number of Shares | shares	139,032
Non-compete agreement costs		$ 400,000
Goodwill	$ 49,891,000
Loans and loans held for sale	$ 628,030,000
Nonqualified Stock Options [Member] | SBM Financial, Inc. [Member]
Business Acquisition [Line Items]
Business Acquisition, Stock for Stock Consideration, Conversion Ratio	8.132
Equity interest issued	$ 1,990,000
Scenario, Adjustment [Member] | SBM Financial, Inc. [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net	960,000
Loans and loans held for sale	$ 137,000

Mergers and Acquisitions - Esti

Mergers and Acquisitions - Estimated Fair Value of Assets Acquired and Liabilities Assumed (Details) - USD ($) $ / shares in Units, $ in Thousands	Oct. 16, 2015	Dec. 31, 2017	Dec. 31, 2016	Sep. 14, 2016	Dec. 31, 2015
Business Acquisition [Line Items]
Equity interest issued		$ 0	$ 0		$ 110,551
Goodwill		$ 94,697	$ 94,697		$ 95,657
Share Price				$ 31.75
SBM Financial, Inc. [Member]
Business Acquisition [Line Items]
Cash	$ 26,125
Equity interest issued	108,561
Total consideration paid	136,676
Loans and loans held for sale	628,030
Cash and due from banks	86,042
Investments	39,742
Deferred tax assets	25,782
Premises and equipment	23,944
OREO	729
Core deposit intangible assets	6,608
Other assets	5,408
Deposits and borrowings	721,186
Other liabilities	8,314
Total identified assets acquired and liabilities assumed, at fair value	86,785
Goodwill	$ 49,891
Business Acquisition, Equity Interest Issued or Issuable, Number of Shares	4,124,643
Share Price	$ 26.32
Nonqualified Stock Options [Member] | SBM Financial, Inc. [Member]
Business Acquisition [Line Items]
Equity interest issued	$ 1,990
Predecessor [Member] | SBM Financial, Inc. [Member]
Business Acquisition [Line Items]
Loans and loans held for sale	639,390
Cash and due from banks	86,042
Investments	39,716
Deferred tax assets	26,293
Premises and equipment	16,851
OREO	2,530
Core deposit intangible assets	0
Other assets	5,421
Deposits and borrowings	719,640
Other liabilities	8,512
Total identified assets acquired and liabilities assumed, at fair value	88,091
Scenario, Adjustment [Member] | SBM Financial, Inc. [Member]
Business Acquisition [Line Items]
Loans and loans held for sale	137
Cash and due from banks	0
Investments	0
Deferred tax assets	666
Premises and equipment	0
OREO	0
Core deposit intangible assets	0
Other assets	157
Deposits and borrowings	0
Other liabilities	0
Total identified assets acquired and liabilities assumed, at fair value	960
Estimate of Fair Value Measurement [Member] | Scenario, Adjustment [Member] | SBM Financial, Inc. [Member]
Business Acquisition [Line Items]
Loans and loans held for sale	(11,497)
Cash and due from banks	0
Investments	26
Deferred tax assets	(1,177)
Premises and equipment	7,093
OREO	(1,801)
Core deposit intangible assets	6,608
Other assets	(170)
Deposits and borrowings	1,546
Other liabilities	(198)
Total identified assets acquired and liabilities assumed, at fair value	$ (2,266)

Mergers and Acquisitions - Pro

Mergers and Acquisitions - Pro Forma Information (Details)	12 Months Ended
	Dec. 31, 2016
SBM Financial, Inc. [Member]
Business Acquisition [Line Items]
Effective income tax rate (percent)	35.00%

Mergers and Acquisitions Acquis

Mergers and Acquisitions Acquisition Costs (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Business Acquisition [Line Items]
Labor and Related Expense	$ 49,965	$ 48,072	$ 37,220
Equipment And Software Expense	9,894	9,557	8,057
Occupancy, Net	6,884	7,088	5,695
Professional Fees	3,118	3,234	2,625
Other Noninterest Expense	10,948	10,687	9,210
Business Combination, Acquisition Related Costs	0	866	10,415
SBM Financial, Inc. [Member]
Business Acquisition [Line Items]
Labor and Related Expense	0	8
Equipment And Software Expense	0	279
Occupancy, Net	0	439
Professional Fees	0	80
Other Noninterest Expense	$ 0	$ 60
Business Acquisition One [Member]
Business Acquisition [Line Items]
Labor and Related Expense			3,240
Equipment And Software Expense			1,531
Occupancy, Net			1,237
Professional Fees			2,453
Other Noninterest Expense			$ 1,954

Securities (Additional Informat

Securities (Additional Information) (Details)	12 Months Ended
	Dec. 31, 2017USD ($)security	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)
Schedule of Investments [Line Items]
Unrealized gains on securities available-for-sale included in accumulated other comprehensive income, net of deferred taxes	$ (10,300,000)	$ (6,085,000)
Unrealized gains on securities available-for-sale included in accumulated other comprehensive income, deferred taxes	$ 2,821,000	3,227,000
Number of investment securities which had unrealized losses for twelve months or longer | security	209
AFS and HTM securities in Continues Unrealized Loss Position	$ 741,200,000	658,500,000
AFS and HTM Securities Unrealized Loss Accumulated in Investments	14,500,000	13,200,000
Investment securities with unrealized losses for twelve months or longer	398,360,000	103,708,000
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	11,172,000	3,850,000
Investment securities with unrealized losses that are considered temporary	722,438,000	615,699,000
Available For Sale Securities Continuous Unrealized Loss Position Aggregate Losses Accumulated In Investments	(14,261,000)	(12,536,000)
Other than temporary impairment losses		0
Federal Home Loan Bank Stock	18,300,000	17,800,000
Federal Reserve Bank Stock	5,400,000
Dividend income from subsidiary	1,100,000	1,000,000	$ 579,000
Carrying value of investments sold	19,500,000	28,800,000	12,400,000
Security pledged as collateral, amortized cost	702,500,000	597,300,000
Security pledged as collateral, fair value	$ 691,200,000	$ 589,700,000
Unrealized Loss as a Percent of Amortized Cost	2.00%	2.00%
Gross realized gains	$ 869,000	$ 125,000	221,000
Mortgage Backed Securities and Collateralized Mortgage Obligations [Member]
Schedule of Investments [Line Items]
Investment securities with unrealized losses for twelve months or longer	398,400,000	103,700,000
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	11,200,000	3,900,000
Available-for-sale Securities [Member]
Schedule of Investments [Line Items]
Unrealized gains on securities available-for-sale included in accumulated other comprehensive income, deferred taxes	2,800,000	3,300,000
Gross realized gains	$ 855,000	$ 51,000	$ 4,000

Securities (Summary of Amortize

Securities (Summary of Amortized Costs and Estimated Fair Values of Available-For-Sale Securities) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Schedule of Investments [Line Items]
Available-for-sale, Amortized Cost	$ 803,021	$ 789,229
Available-for-sale, Unrealized Gains	1,139	3,174
Available-for-sale, Unrealized Losses	(14,261)	(12,536)
AFS securities	789,899	779,867
Held-to-maturity Securities	94,073	94,609
Held-to-maturity Securities, Accumulated Unrecognized Holding Gain	1,077	618
Held-to-maturity Securities, Accumulated Unrecognized Holding Loss	(237)	(631)
Held-to-maturity Securities, Fair Value	94,913	94,596
US Government Corporations and Agencies Securities [Member]
Schedule of Investments [Line Items]
Held-to-maturity Securities	94,073	94,609
Held-to-maturity Securities, Accumulated Unrecognized Holding Gain	1,077	618
Held-to-maturity Securities, Accumulated Unrecognized Holding Loss	(237)	(631)
Held-to-maturity Securities, Fair Value	94,913	94,596
Obligations of states and political subdivisions [Member]
Schedule of Investments [Line Items]
Available-for-sale, Amortized Cost	7,232	8,848
Available-for-sale, Unrealized Gains	103	153
Available-for-sale, Unrealized Losses	0	0
AFS securities	7,335	9,001
Mortgage-backed securities issued or guaranteed by U.S. government sponsored enterprises [Member]
Schedule of Investments [Line Items]
Available-for-sale, Amortized Cost	510,176	485,222
Available-for-sale, Unrealized Gains	597	2,515
Available-for-sale, Unrealized Losses	(7,471)	(7,115)
AFS securities	503,302	480,622
Collateralized mortgage obligations issued or guaranteed by U.S. government sponsored enterprises [Member]
Schedule of Investments [Line Items]
Available-for-sale, Amortized Cost	279,575	289,046
Available-for-sale, Unrealized Gains	14	265
Available-for-sale, Unrealized Losses	(6,790)	(5,421)
AFS securities	272,799	283,890
Corporate Debt Securities [Member]
Schedule of Investments [Line Items]
Available-for-sale, Amortized Cost	5,484	5,481
Available-for-sale, Unrealized Gains	173	132
Available-for-sale, Unrealized Losses	0	0
AFS securities	5,657	5,613
Debt Securities [Member]
Schedule of Investments [Line Items]
Available-for-sale, Amortized Cost	802,467	788,597
Available-for-sale, Unrealized Gains	887	3,065
Available-for-sale, Unrealized Losses	(14,261)	(12,536)
AFS securities	789,093	779,126
Equity Securities [Member]
Schedule of Investments [Line Items]
Available-for-sale, Amortized Cost	554	632
Available-for-sale, Unrealized Gains	252	109
Available-for-sale, Unrealized Losses	0	0
AFS securities	$ 806	$ 741

Securities (Unrealized Gross Lo

Securities (Unrealized Gross Losses and Estimated Fair values of Investment Securities by Length of Time that Individual Securities in Each Category in Continuous Loss Position) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Schedule of Available-for-sale Securities [Line Items]
Fair Value - Less Than 12 Months	$ 324,078	$ 511,991
Unrealized Losses - Less Than 12 Months	(3,089)	(8,686)
Fair Value - 12 Months or More	398,360	103,708
Unrealized Losses - 12 Months or More	(11,172)	(3,850)
Fair Value	722,438	615,699
Unrealized Losses	(14,261)	(12,536)
Available-for-sale Securities, Amortized Cost Basis	803,021	789,229
Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax	1,139	3,174
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	9,317	42,805
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(57)	(631)
Held-to-maturity Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	9,436	0
Held-to-maturity Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(180)	0
Held-to-maturity Securities, Continuous Unrealized Loss Position, Fair Value	18,753	42,805
Held-to-maturity Securities, Continuous Unrealized Loss Position, Accumulated Loss	(237)	(631)
Obligations of U.S. government sponsored enterprises [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair Value - Less Than 12 Months	221,466	348,579
Unrealized Losses - Less Than 12 Months	(2,393)	(5,780)
Fair Value - 12 Months or More	233,971	29,496
Unrealized Losses - 12 Months or More	(5,078)	(1,335)
Fair Value	455,437	378,075
Unrealized Losses	(7,471)	(7,115)
Collateralized mortgage obligations
Schedule of Available-for-sale Securities [Line Items]
Fair Value - Less Than 12 Months	102,612	163,412
Unrealized Losses - Less Than 12 Months	(696)	(2,906)
Fair Value - 12 Months or More	164,389	74,212
Unrealized Losses - 12 Months or More	(6,094)	(2,515)
Fair Value	267,001	237,624
Unrealized Losses	(6,790)	(5,421)
Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost Basis	5,484	5,481
Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax	173	132
Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost Basis	554	632
Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax	252	109
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost Basis	510,176	485,222
Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax	597	2,515
US States and Political Subdivisions Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost Basis	7,232	8,848
Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax	103	153
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	9,317
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(57)
Held-to-maturity Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	9,436
Held-to-maturity Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(180)
Held-to-maturity Securities, Continuous Unrealized Loss Position, Fair Value	18,753
Held-to-maturity Securities, Continuous Unrealized Loss Position, Accumulated Loss	$ (237)
US Government Corporations and Agencies Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value		42,805
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		(631)
Held-to-maturity Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		0
Held-to-maturity Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		0
Held-to-maturity Securities, Continuous Unrealized Loss Position, Fair Value		42,805
Held-to-maturity Securities, Continuous Unrealized Loss Position, Accumulated Loss		$ (631)

Securities (Company's Sales of

Securities (Company's Sales of Securities) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Schedule of Available-for-sale Securities [Line Items]
Unrealized Loss as a Percent of Amortized Cost	2.00%	2.00%
Proceeds from sales of securities	$ 20,366	$ 28,850	$ 12,426
Gross realized gains	869	125	221
Gross realized losses	$ (14)	$ (74)	(217)
Previously recorded OTTI			$ (204)

Securities (Amortized Cost and

Securities (Amortized Cost and Estimated Fair Values of Debt Securities by Contractual Maturity) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Available-for-sale, Amortized Cost
Due in one year or less	$ 4,986
Due after one year through five years	104,294
Due after five years through ten years	212,809
Due after ten years	480,378
Total	802,467
Available-for-sale, Fair Value
Due in one year or less	4,983
Due after one year through five years	103,572
Due after five years through ten years	209,663
Due after ten years	470,875
Total	789,093
Due in one year or less	751
Held-to-maturity, Amortized Cost
Due in one year or less	751
Due after one year through five years	4,705
Due after five years through ten years	10,110
Due after ten years	78,507
Held-to-maturity Securities	94,073	$ 94,609
Held-to-maturity, Fair Value
Held-to-maturity Securities, Debt Maturities, Remainder of Fiscal Year, Fair Value	751
Due after one year through five years	4,721
Due after five years through ten years	10,192
Due after ten years	79,249
Held-to-maturity Securities, Fair Value	$ 94,913	$ 94,596

Loans and Allowance for Loan 62

Loans and Allowance for Loan Losses (Additional Information) (Details)	12 Months Ended
	Dec. 31, 2017USD ($)loan	Dec. 31, 2016USD ($)loan	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Individually Evaluated for Impairment	$ 13,590,000	$ 20,254,000	$ 15,235,000
Financing receivable, allowance for credit losses	24,171,000	23,116,000	21,166,000	$ 21,116,000
Foregone interest	$ 843,000	$ 888,000	$ 586,000
Number of Portfolio Concentration Industries	0
Financing Receivable, Modifications, Number of Contracts	5	6	1
Allowance Related to Troubled Debt Restructurings assigned during period	$ 45,000	$ 1,400,000	$ 27,000
Loans and Leases Receivable, Impaired, Commitment to Lend	0
Financing Receivable, Modifications, Subsequent Default, Recorded Investment	0	0	0
HPFC Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Individually Evaluated for Impairment		97,000
Financing receivable, allowance for credit losses	451,000	672,000	24,000
Unallocated Financing Receivables [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, allowance for credit losses	0	0	0	2,384,000
Residential real estate loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Individually Evaluated for Impairment	$ 5,171,000	4,348,000	6,026,000
Term to maturity (years)	30 years
Financing receivable, allowance for credit losses	$ 5,086,000	4,160,000	4,545,000	4,899,000
Financing Receivable in Process of Foreclosure	1,900,000	1,400,000
Loans Receivable [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans restructured due to credit difficulties that are now performing	5,000,000	4,300,000
Financing Receivables Impaired Troubled Debt Restructuring Non-Performing	1,200,000	1,400,000
Consumer loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Individually Evaluated for Impairment		7,000	74,000
Financing receivable, allowance for credit losses	233,000	181,000	$ 193,000	$ 281,000
Minimum [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Individually Evaluated for Impairment	$ 500,000	250,000
Number of Months	18
Minimum [Member] | HPFC Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Term to maturity (years)	7 years
Maximum [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of Months	24
Maximum [Member] | HPFC Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Term to maturity (years)	10 years
Total Loan Portfolio [Member] | Loan Concentration Risk [Member] | Non-Residential Building Operators Industry Sector [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Concentration Risk, Percentage	11.00%
Commercial real estate loans | Loan Concentration Risk [Member] | Non-Residential Building Operators Industry Sector [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Concentration Risk, Percentage	27.00%
Commercial loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of Loans	1
Loans and Leases Receivable, Impaired, Commitment to Lend	$ 280,000
Commercial loans | Extended Maturity [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans restructured due to credit difficulties that are now performing	$ 22,000	$ 47,000
Financing Receivable, Modifications, Number of Contracts	0	6	0
Allowance Related to Troubled Debt Restructurings assigned during period	$ 0	$ 1,400,000	$ 0

Loans and Allowance for Loan 63

Loans and Allowance for Loan Losses (Composition of Loan Portfolio, Excluding Residential Loans Held for Sale) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans:	$ 2,782,439	$ 2,594,564	$ 2,490,206
Residential real estate loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	858,369	802,494
Loans:	858,369	802,494	820,617
Commercial real estate loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	1,164,023	1,050,780
Loans:	1,164,023	1,050,780	927,951
Commercial loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	373,400	333,639
Loans:	373,400	333,639	297,721
Home equity loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	323,378	329,907
Loans:	323,378	329,907	348,634
Consumer loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	18,149	17,332
Loans:	18,149	17,332	17,953
HPFC Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	45,120	60,412
Loans:	$ 45,120	$ 60,412	$ 77,330

Loans and Allowance for Loan 64

Loans and Allowance for Loan Losses (Schedule of FV mark amortization) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Receivables [Abstract]
Net Unamortized fair Value Mark (Discount) on Loans	$ 6,207	$ 8,810
Loans and Leases Receivable, Deferred Income	(963)	(66)
Unamortized Loan Commitment and Origination Fees and Unamortized Discounts or Premiums	$ 5,244	$ 8,744

Loans and Allowance for Loan 65

Loans and Allowance for Loan Losses (Schedule of Loans Made to Related Parties) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Loans and Leases Receivable, Related Parties [Roll Forward]
Balance at beginning of year	$ 15,942	$ 16,628
Loans made/advanced and additions	230	434
Repayments and reductions	(3,032)	(1,120)
Balance at end of year	$ 13,140	$ 15,942

Loans and Allowance for Loan 66

Loans and Allowance for Loan Losses (Activity in Allowance for Loan Losses by Portfolio Segment) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Financing Receivable, Allowance for Credit Losses [Line Items]
Reserve for unfunded commitments	$ 20,000	$ 11,000	$ 22,000
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance	23,116,000	21,166,000	21,116,000
Loans charged off	(2,468,000)	(3,805,000)	(2,616,000)
Recoveries	497,000	486,000	728,000
Provision for Loan and Lease Losses	3,026,000	5,269,000	1,938,000
Ending balance	24,171,000	23,116,000	21,166,000
Ending Balance: Individually evaluated for impairment	2,009,000	2,007,000	1,369,000
Ending Balance: Collectively evaluated for impairment	22,162,000	21,109,000	19,797,000
Ending Balance: Individually evaluated for impairment	13,590,000	20,254,000	15,235,000
Ending Balance: Collectively evaluated for impairment	2,768,849,000	2,574,310,000	2,474,971,000
Total loan balances	2,782,439,000	2,594,564,000	2,490,206,000
Residential real estate loans
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance	4,160,000	4,545,000	4,899,000
Loans charged off	(482,000)	(356,000)	(801,000)
Recoveries	30,000	95,000	55,000
Provision for Loan and Lease Losses	1,378,000	(124,000)	392,000
Ending balance	5,086,000	4,160,000	4,545,000
Ending Balance: Individually evaluated for impairment	568,000	483,000	544,000
Ending Balance: Collectively evaluated for impairment	4,518,000	3,677,000	4,001,000
Ending Balance: Individually evaluated for impairment	5,171,000	4,348,000	6,026,000
Ending Balance: Collectively evaluated for impairment	853,198,000	798,146,000	814,591,000
Total loan balances	858,369,000	802,494,000	820,617,000
Commercial real estate loans
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance	12,154,000	10,432,000	7,951,000
Loans charged off	(124,000)	(315,000)	(481,000)
Recoveries	141,000	50,000	74,000
Provision for Loan and Lease Losses	(308,000)	1,987,000	2,888,000
Ending balance	11,863,000	12,154,000	10,432,000
Ending Balance: Individually evaluated for impairment	1,441,000	1,373,000	644,000
Ending Balance: Collectively evaluated for impairment	10,422,000	10,781,000	9,788,000
Ending Balance: Individually evaluated for impairment	6,199,000	13,317,000	4,610,000
Ending Balance: Collectively evaluated for impairment	1,157,824,000	1,037,463,000	923,341,000
Total loan balances	1,164,023,000	1,050,780,000	927,951,000
Commercial loans
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance	3,755,000	3,241,000	3,354,000
Loans charged off	(1,014,000)	(2,218,000)	(655,000)
Recoveries	301,000	332,000	389,000
Provision for Loan and Lease Losses	1,129,000	2,400,000	153,000
Ending balance	4,171,000	3,755,000	3,241,000
Ending Balance: Individually evaluated for impairment			92,000
Ending Balance: Collectively evaluated for impairment	4,171,000	3,755,000	3,149,000
Ending Balance: Individually evaluated for impairment	1,791,000	2,028,000	3,937,000
Ending Balance: Collectively evaluated for impairment	371,609,000	331,611,000	293,784,000
Total loan balances	373,400,000	333,639,000	297,721,000
Home equity loans
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance	2,194,000	2,731,000	2,247,000
Loans charged off	(434,000)	(308,000)	(525,000)
Recoveries	2,000	2,000	188,000
Provision for Loan and Lease Losses	605,000	(231,000)	821,000
Ending balance	2,367,000	2,194,000	2,731,000
Ending Balance: Individually evaluated for impairment		86,000	89,000
Ending Balance: Collectively evaluated for impairment	2,367,000	2,108,000	2,642,000
Ending Balance: Individually evaluated for impairment	429,000	457,000	588,000
Ending Balance: Collectively evaluated for impairment	322,949,000	329,450,000	348,046,000
Total loan balances	323,378,000	329,907,000	348,634,000
Consumer loans
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance	181,000	193,000	281,000
Loans charged off	(124,000)	(101,000)	(154,000)
Recoveries	17,000	7,000	22,000
Provision for Loan and Lease Losses	159,000	82,000	44,000
Ending balance	233,000	181,000	193,000
Ending Balance: Collectively evaluated for impairment	233,000	181,000	193,000
Ending Balance: Individually evaluated for impairment		7,000	74,000
Ending Balance: Collectively evaluated for impairment	18,149,000	17,325,000	17,879,000
Total loan balances	18,149,000	17,332,000	17,953,000
HPFC Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance	672,000	24,000
Loans charged off	(290,000)	(507,000)
Recoveries	6,000
Provision for Loan and Lease Losses	63,000	1,155,000	24,000
Ending balance	451,000	672,000	24,000
Ending Balance: Individually evaluated for impairment		65,000
Ending Balance: Collectively evaluated for impairment	451,000	607,000	24,000
Ending Balance: Individually evaluated for impairment		97,000
Ending Balance: Collectively evaluated for impairment	45,120,000	60,315,000	77,330,000
Total loan balances	45,120,000	60,412,000	77,330,000
Unallocated
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance	0	0	2,384,000
Provision for Loan and Lease Losses			(2,384,000)
Ending balance	$ 0	$ 0	$ 0

Loans and Allowance for Loan 67

Loans and Allowance for Loan Losses (Schedule of Provision for Credit Losses) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Receivables [Abstract]
Provision (credit)									$ 3,026	$ 5,269	$ 1,938
Provision for Other Credit Losses									9	(11)	(2)
Provision for credit losses	$ 238	$ 817	$ 1,401	$ 579	$ 255	$ 1,279	$ 2,852	$ 872	$ 3,035	$ 5,258	$ 1,936

Loans and Allowance for Loan 68

Loans and Allowance for Loan Losses (Credit Risk Exposure Indicators by Portfolio Segment) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Financing Receivable, Recorded Investment [Line Items]
Loans:	$ 2,782,439	$ 2,594,564	$ 2,490,206
Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans:	2,374,582	2,173,031
Performing Financing Receivable
Financing Receivable, Recorded Investment [Line Items]
Loans:	339,876	345,615
Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans:	22,784	13,966
Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans:	43,546	58,872
Doubtful [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans:		1,456
Nonperforming Financing Receivable
Financing Receivable, Recorded Investment [Line Items]
Loans:	1,651	1,624
Residential real estate loans
Financing Receivable, Recorded Investment [Line Items]
Loans:	858,369	802,494	820,617
Residential real estate loans | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans:	846,394	789,554
Residential real estate loans | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans:	922	2,387
Residential real estate loans | Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans:	11,053	10,553
Commercial real estate loans
Financing Receivable, Recorded Investment [Line Items]
Loans:	1,164,023	1,050,780	927,951
Commercial real estate loans | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans:	1,130,235	1,003,386
Commercial real estate loans | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans:	9,154	5,724
Commercial real estate loans | Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans:	24,634	41,670
Commercial loans
Financing Receivable, Recorded Investment [Line Items]
Loans:	373,400	333,639	297,721
Commercial loans | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans:	354,904	321,148
Commercial loans | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans:	12,517	5,598
Commercial loans | Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans:	5,979	5,437
Commercial loans | Doubtful [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans:		1,456
Home equity loans
Financing Receivable, Recorded Investment [Line Items]
Loans:	323,378	329,907	348,634
Home equity loans | Performing Financing Receivable
Financing Receivable, Recorded Investment [Line Items]
Loans:	321,727	328,287
Home equity loans | Nonperforming Financing Receivable
Financing Receivable, Recorded Investment [Line Items]
Loans:	1,651	1,620
Consumer loans
Financing Receivable, Recorded Investment [Line Items]
Loans:	18,149	17,332	17,953
Consumer loans | Performing Financing Receivable
Financing Receivable, Recorded Investment [Line Items]
Loans:	18,149	17,328
Consumer loans | Nonperforming Financing Receivable
Financing Receivable, Recorded Investment [Line Items]
Loans:		4
HPFC Portfolio Segment [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans:	45,120	60,412	$ 77,330
HPFC Portfolio Segment [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans:	43,049	58,943
HPFC Portfolio Segment [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans:	191	257
HPFC Portfolio Segment [Member] | Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans:	$ 1,880	$ 1,212

Loans and Allowance for Loan 69

Loans and Allowance for Loan Losses (Loan Aging Analysis by Portfolio Segment (Including Loans Past Due Over Ninety Days and Non Accrual Loans) and Summary of Non Accrual Loans) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	$ 22,945	$ 25,465
Current	2,759,494	2,569,099
Total loan balances	2,782,439	2,594,564	$ 2,490,206
Non-Accrual Loans	15,314	20,713
Residential real estate loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	9,477	5,611
Current	848,892	796,883
Total loan balances	858,369	802,494	820,617
Non-Accrual Loans	4,979	3,945
Commercial real estate loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	6,700	13,703
Current	1,157,323	1,037,077
Total loan balances	1,164,023	1,050,780	927,951
Non-Accrual Loans	5,642	12,849
Commercial loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	2,223	2,526
Current	371,177	331,113
Total loan balances	373,400	333,639	297,721
Non-Accrual Loans	2,000	2,088
Home equity loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	2,548	2,347
Current	320,830	327,560
Total loan balances	323,378	329,907	348,634
Non-Accrual Loans	1,650	1,620
Consumer loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	67	42
Current	18,082	17,290
Total loan balances	18,149	17,332	17,953
Non-Accrual Loans		4
HPFC Portfolio Segment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	1,930	1,236
Current	43,190	59,176
Total loan balances	45,120	60,412	$ 77,330
Non-Accrual Loans	1,043	207
Financing Receivables, 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	6,291	4,639
Financing Receivables, 30 to 59 Days Past Due [Member] | Residential real estate loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	3,871	1,783
Financing Receivables, 30 to 59 Days Past Due [Member] | Commercial real estate loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	849	855
Financing Receivables, 30 to 59 Days Past Due [Member] | Commercial loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	329	633
Financing Receivables, 30 to 59 Days Past Due [Member] | Home equity loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	1,046	892
Financing Receivables, 30 to 59 Days Past Due [Member] | Consumer loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	57	38
Financing Receivables, 30 to 59 Days Past Due [Member] | HPFC Portfolio Segment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	139	438
Financing Receivables, 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	3,822	2,187
Financing Receivables, 60 to 89 Days Past Due [Member] | Residential real estate loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	1,585	924
Financing Receivables, 60 to 89 Days Past Due [Member] | Commercial real estate loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	323	223
Financing Receivables, 60 to 89 Days Past Due [Member] | Commercial loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	359	218
Financing Receivables, 60 to 89 Days Past Due [Member] | Home equity loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	173	134
Financing Receivables, 60 to 89 Days Past Due [Member] | Consumer loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	10
Financing Receivables, 60 to 89 Days Past Due [Member] | HPFC Portfolio Segment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	1,372	688
Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	12,832	18,639
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Residential real estate loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	4,021	2,904
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Commercial real estate loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	5,528	12,625
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Commercial loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	1,535	1,675
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Home equity loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	1,329	1,321
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Consumer loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		4
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | HPFC Portfolio Segment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	$ 419	$ 110

Loans and Allowance for Loan 70

Loans and Allowance for Loan Losses (Summary of All Troubled Debt Restructuring Loans (Accruing and Non Accruing) by Portfolio Segment) (Details)	3 Months Ended	12 Months Ended
	Sep. 30, 2017USD ($)	Dec. 31, 2017USD ($)loan	Dec. 31, 2016USD ($)loan	Dec. 31, 2015USD ($)loan
Financing Receivable, Modifications [Line Items]
Financing Receivable Modifications Number Of Contracts Outstanding | loan		36	35
Financing Receivable, Modifications, Recorded Investment		$ 6,232,000	$ 5,747,000
Specific Reserve		$ 468,000	$ 483,000
Number of Contracts		5	6	1
Pre-Modification Outstanding Recorded Investment		$ 895,000	$ 2,973,000	$ 74,000
Post-Modification Outstanding Recorded Investment		914,000	2,973,000	78,000
Specific Reserve		45,000	1,400,000	27,000
Recorded investment of troubled-debt restructurings that subsequently defaulted		$ 0	$ 0	$ 0
Commercial loans
Financing Receivable, Modifications [Line Items]
Financing Receivable Modifications Number Of Contracts Outstanding | loan		7	10
Financing Receivable, Modifications, Recorded Investment		$ 1,345,000	$ 1,502,000
Specific Reserve		$ 0	$ 0
Home equity loans
Financing Receivable, Modifications [Line Items]
Financing Receivable Modifications Number Of Contracts Outstanding | loan		2	1
Financing Receivable, Modifications, Recorded Investment		$ 307,000	$ 16,000
Specific Reserve		$ 0	$ 0
Residential real estate
Financing Receivable, Modifications [Line Items]
Financing Receivable Modifications Number Of Contracts Outstanding | loan		24	21
Financing Receivable, Modifications, Recorded Investment		$ 3,604,000	$ 3,221,000
Specific Reserve		$ 452,000	$ 483,000
Commercial Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable Modifications Number Of Contracts Outstanding | loan		3	3
Financing Receivable, Modifications, Recorded Investment		$ 976,000	$ 1,008,000
Specific Reserve		$ 16,000	$ 0
Residential Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts | loan		1	0	0
Pre-Modification Outstanding Recorded Investment		$ 148,000	$ 0	$ 0
Post-Modification Outstanding Recorded Investment		$ 156,000	0	0
Specific Reserve	$ 30,000		$ 0	$ 0
Home Equity Loan [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts | loan		1	0	0
Pre-Modification Outstanding Recorded Investment		$ 315,000	$ 0	$ 0
Post-Modification Outstanding Recorded Investment		315,000	0	0
Specific Reserve		$ 0	$ 0	$ 0
Extended Maturity [Member] | Residential real estate
Financing Receivable, Modifications [Line Items]
Number of Contracts		2	0	0
Pre-Modification Outstanding Recorded Investment		$ 298,000	$ 0	$ 0
Post-Modification Outstanding Recorded Investment		298,000	0	0
Specific Reserve		$ 15,000	$ 0	$ 0
Extended Maturity [Member] | Commercial loans
Financing Receivable, Modifications [Line Items]
Number of Contracts		0	6	0
Pre-Modification Outstanding Recorded Investment		$ 0	$ 2,973,000	$ 0
Post-Modification Outstanding Recorded Investment		0	2,973,000	0
Specific Reserve		$ 0	$ 1,400,000	$ 0
Court Order [Member] | Residential real estate
Financing Receivable, Modifications [Line Items]
Number of Contracts		0	0	1
Pre-Modification Outstanding Recorded Investment		$ 0	$ 0	$ 74,000
Post-Modification Outstanding Recorded Investment		0	0	78,000
Specific Reserve		$ 0	$ 0	$ 27,000
Contractual Interest Rate Reduction [Member] | Residential Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts | loan		1	0	0
Pre-Modification Outstanding Recorded Investment		$ 134,000	$ 0	$ 0
Post-Modification Outstanding Recorded Investment		145,000	0	0
Specific Reserve		$ 0	$ 0	$ 0

Loans and Allowance for Loan 71

Loans and Allowance for Loan Losses (Summary of Impaired Loan Balances and Associated Allowance by Portfolio Segment) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Financing Receivable, Impaired [Line Items]
Recorded investment with related allowance recorded	$ 9,280	$ 14,858	$ 5,475
Unpaid principal balance with related allowance recorded	9,280	14,858	5,507
Average recorded investment with related allowance recorded	12,257	9,418	9,857
Interest income recognized with related allowance recorded	153	106	114
Recorded investment without related allowance recorded	4,310	5,396	9,760
Unpaid principal balance without related allowance recorded	6,216	7,756	12,942
Impaired Financing Receivable With No Related Allowance Related Allowance	0	0
Average recorded investment without related allowance recorded	4,709	6,970	6,695
Interest income recognized without related allowance recorded	62	76	90
Recorded investment, total impaired loans	13,590	20,254	15,235
Unpaid principal balance, total impaired loans	15,496	22,614	18,449
Related allowance, total impaired loans	2,009	2,007	1,369
Average recorded investment, total impaired loans	16,966	16,388	16,552
Interest income recognized, total impaired loans	215	182	204
Residential real estate loans
Financing Receivable, Impaired [Line Items]
Recorded investment with related allowance recorded	3,858	3,019	3,191
Unpaid principal balance with related allowance recorded	3,858	3,019	3,191
Average recorded investment with related allowance recorded	3,177	3,088	6,064
Interest income recognized with related allowance recorded	131	106	112
Recorded investment without related allowance recorded	1,313	1,329	2,835
Unpaid principal balance without related allowance recorded	1,673	1,800	4,353
Impaired Financing Receivable With No Related Allowance Related Allowance	0	0
Average recorded investment without related allowance recorded	1,345	2,057	2,175
Interest income recognized without related allowance recorded	15	9	8
Related allowance, total impaired loans	568	483	544
Commercial real estate loans
Financing Receivable, Impaired [Line Items]
Recorded investment with related allowance recorded	5,422	11,443	1,825
Unpaid principal balance with related allowance recorded	5,422	11,443	1,857
Average recorded investment with related allowance recorded	8,900	5,165	1,753
Interest income recognized with related allowance recorded	22
Recorded investment without related allowance recorded	777	1,874	2,785
Unpaid principal balance without related allowance recorded	1,084	2,369	3,426
Impaired Financing Receivable With No Related Allowance Related Allowance	0	0
Average recorded investment without related allowance recorded	1,132	2,214	2,719
Interest income recognized without related allowance recorded	29	51	65
Related allowance, total impaired loans	1,441	1,373	644
Commercial loans
Financing Receivable, Impaired [Line Items]
Recorded investment with related allowance recorded			156
Unpaid principal balance with related allowance recorded			156
Average recorded investment with related allowance recorded	31	762	945
Interest income recognized with related allowance recorded			2
Recorded investment without related allowance recorded	1,791	2,028	3,781
Unpaid principal balance without related allowance recorded	2,964	3,209	4,325
Impaired Financing Receivable With No Related Allowance Related Allowance	0	0
Average recorded investment without related allowance recorded	1,920	2,507	1,412
Interest income recognized without related allowance recorded	10	16	17
Related allowance, total impaired loans	0	0	92
Home equity loans
Financing Receivable, Impaired [Line Items]
Recorded investment with related allowance recorded		299	303
Unpaid principal balance with related allowance recorded		299	303
Average recorded investment with related allowance recorded	125	305	900
Recorded investment without related allowance recorded	429	158	285
Unpaid principal balance without related allowance recorded	495	368	688
Impaired Financing Receivable With No Related Allowance Related Allowance	0	0
Average recorded investment without related allowance recorded	310	180	369
Interest income recognized without related allowance recorded	8
Related allowance, total impaired loans	0	86	89
Consumer loans
Financing Receivable, Impaired [Line Items]
Average recorded investment with related allowance recorded			195
Recorded investment without related allowance recorded		7	74
Unpaid principal balance without related allowance recorded		10	150
Impaired Financing Receivable With No Related Allowance Related Allowance	0	0
Average recorded investment without related allowance recorded	2	12	$ 20
Related allowance, total impaired loans	0	0
HPFC Portfolio Segment [Member]
Financing Receivable, Impaired [Line Items]
Recorded investment with related allowance recorded		97
Unpaid principal balance with related allowance recorded		97
Average recorded investment with related allowance recorded	24	98
Impaired Financing Receivable With No Related Allowance Related Allowance	0	0
Average recorded investment without related allowance recorded
Related allowance, total impaired loans	$ 0	$ 65

Goodwill (Changes in Goodwill)

Goodwill (Changes in Goodwill) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2017
Goodwill [Line Items]
Goodwill	$ 98,267	$ 99,227	$ 98,267
Accumulated impairment losses	(3,570)	(3,570)	(3,570)
Reported goodwill	94,697	95,657	94,697
Activity for the year		960
Banking
Goodwill [Line Items]
Goodwill	90,793	91,753	90,793
Accumulated impairment losses	0	0	0
Reported goodwill	90,793	91,753	90,793
Activity for the year		960
Financial Services
Goodwill [Line Items]
Goodwill	7,474	7,474	7,474
Accumulated impairment losses	(3,570)	(3,570)	(3,570)
Reported goodwill	3,904	$ 3,904	$ 3,904
Activity for the year	$ 0

Goodwill (Additional Informatio

Goodwill (Additional Information) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill, Impairment Loss, Net of Tax	$ 0	$ 0	$ 0

Other Intangible Assets (Schedu

Other Intangible Assets (Schedule of Finite-Lived Intangible Assets) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Gross Carrying Amount
Total	$ 24,661	$ 24,661
Accumulated Amortization
Total	(19,706)	(17,897)
Net Carrying Amount
Total	4,955	6,764
Amortization of intangible assets	1,809	1,903	$ 1,306
Core Deposits [Member]
Gross Carrying Amount
Total	23,908	23,908
Accumulated Amortization
Total	(18,953)	(17,220)
Net Carrying Amount
Total	4,955	6,688
Trust Relationship [Member]
Gross Carrying Amount
Total	753	753
Accumulated Amortization
Total	(753)	(677)
Net Carrying Amount
Total	$ 0	$ 76

Other Intangible Assets (Sche75

Other Intangible Assets (Schedule of Expected Future Amortization of Intangible Assets) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Other Intangible Assets [Abstract]
2,018	$ 725
2,019	705
2,020	682
2,021	655
2,022	625
Thereafter	1,563
Total	$ 4,955	$ 6,764

Premises and Equipment (Equipme

Premises and Equipment (Equipment) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	$ 76,092	$ 74,013
Accumulated depreciation and amortization	(34,201)	(31,140)
Premises and equipment, net	41,891	42,873
Gain (Loss) on Disposition of Property Plant Equipment	0	(11)	$ 0
Land and land improvements [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	2,985	3,012
Buildings and leasehold improvements [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	37,054	36,958
Furniture, fixtures and equipment [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	36,053	34,043
Software and Software Development Costs [Member]
Property, Plant and Equipment [Line Items]
Accumulated depreciation and amortization	(3,500)	(3,200)
Capitalized Computer Software, Gross	3,800	3,600
Capital lease obligation
Property, Plant and Equipment [Line Items]
Capital Leased Assets, Gross	$ 855	$ 855
SBM Financial, Inc. [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Disposals			$ 1,100

Premises and Equipment - Deprec

Premises and Equipment - Depreciation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Property, Plant and Equipment [Line Items]
Depreciation, Depletion and Amortization, Nonproduction	$ 3,761	$ 4,426	$ 3,614
Equipment [Member]
Property, Plant and Equipment [Line Items]
Depreciation	1,874	1,942	1,620
Building and Building Improvements [Member]
Property, Plant and Equipment [Line Items]
Depreciation	1,643	1,757	1,140
Software Development [Member]
Property, Plant and Equipment [Line Items]
Depreciation	244	275	337
SBM Financial, Inc. [Member] | Property, Plant and Equipment [Member]
Property, Plant and Equipment [Line Items]
Depreciation	$ 0	$ 452	$ 517

Premises and Equipment (Leases)

Premises and Equipment (Leases) (Details) $ in Thousands		12 Months Ended
		Dec. 31, 2017USD ($)property	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)
Property, Plant and Equipment [Line Items]
Lease expense		$ 1,500	$ 1,800	$ 1,700
Number of properties | property		1
Lessee Leasing Arrangements, Operating Leases, Term of Contract		5 years
number of lease extensions		2
Lessee Leasing Arrangements, Operating Leases, Renewal Term		5 years
Capital Lease Obligations		$ 791	858
Operating Leases
2,018		1,429
2,019		1,394
2,020		888
2,021		671
2,022		484
Thereafter		1,531
Total		6,397
Capital Leases
2,018		126
2,019		126
2,020		126
2,021		130
2,022		131
Thereafter		425
Total		1,064
Less: amount representing interest	[1]	273
Present value of net minimum lease payments	[2]	$ 791
Capital lease obligation
Property, Plant and Equipment [Line Items]
Year through which capital lease on branch facility will extend		Mar. 31, 2026
Capital lease interest rate		9.75%
Capital lease for a branch facility		$ 855	855
Accumulated depreciation for a branch facility		$ 502	$ 459
Lease Agreements [Member]
Property, Plant and Equipment [Line Items]
Year through which capital lease on branch facility will extend		Dec. 1, 2019
Officer [Member]
Property, Plant and Equipment [Line Items]
number of related parties		2
[1]	Amount necessary to reduce net minimum lease payments to present value calculated at the Company's incremental borrowing rate at lease inception.
[2]	Reflects the liability reported within short- and long-term borrowings on the consolidated statements of condition. At December 31, 2017 and 2016, the capital lease liability was $791,000 and $858,000, respectively.

Mortgage Banking (Additional In

Mortgage Banking (Additional Information) (Details) - USD ($)		12 Months Ended
		Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Servicing Assets at Fair Value [Line Items]
Gain (Loss) on Sale of Mortgage Loans		$ 6,256,000	$ 6,201,000	$ 1,278,000
Receivables Held-for-sale, Amount		8,100,000	15,100,000
Unrealized Gain (Loss) on Derivatives		37,000	(289,000)
Unrealized gain (loss) on loans held for sale		326,000	(422,000)	133,000
Servicing Asset at Amortized Cost		1,025,000	1,210,000	2,161,000	$ 493,000
Servicing Asset at Amortized Cost		$ 1,025,000	$ 1,210,000	2,161,000	$ 493,000
Servicing Assets and Servicing Liabilities at Fair Value, Assumptions Used to Estimate Fair Value, Prepayment Speed		14.00%	14.60%
Servicing Assets and Servicing Liabilities at Fair Value, Assumptions Used to Estimate Fair Value, Discount Rate		11.20%	7.80%
Sensitivity Analysis of Fair Value, Transferor's Interests in Transferred Financial Assets, Impact of 10 Percent Adverse Change in Prepayment Speed		$ 76,000
Sensitivity Analysis of Fair Value, Transferor's Interests in Transferred Financial Assets, Impact of 20 Percent Adverse Change in Prepayment Speed		148,000
Sensitivity Analysis of Fair Value, Transferor's Interests in Transferred Financial Assets, Impact of 10 Percent Adverse Change in Discount Rate		54,000
Sensitivity Analysis of Fair Value, Transferor's Interests in Transferred Financial Assets, Impact of 20 Percent Adverse Change in Discount Rate		105,000
Advance Payments by Borrowers for Taxes and Insurance		194,000	$ 2,000,000
Capitalized servicing right fees upon sale(1)	[1]	22,000	9,000	294,000
Fixed Rate Residential Mortgage [Member]
Servicing Assets at Fair Value [Line Items]
Mortgage Loans on Real Estate, Cost of Mortgages Sold		218,600,000	232,200,000	61,200,000
Custodial escrow balances		4,200,000	11,900,000
Accounts Receivable, Net		58,000	2,700,000
Allowance for Doubtful Accounts Receivable		0	829,000
SBM Financial, Inc. [Member]
Servicing Assets at Fair Value [Line Items]
Capitalized servicing right fees upon sale(1)		0	0	1,608,000
Forward Contracts [Member]
Servicing Assets at Fair Value [Line Items]
Unrealized Gain (Loss) on Derivatives		(136,000)	278,000	0
Servicing Assets [Member]
Servicing Assets at Fair Value [Line Items]
Mortgage loans serviced during period, value		275,200,000	332,700,000
Fees and Commissions, Mortgage Banking and Servicing		1,000,000	1,100,000	597,000
Sub-Serviced Loans [Member]
Servicing Assets at Fair Value [Line Items]
Mortgage loans serviced during period, value		349,700,000	930,800,000
Fees and Commissions, Mortgage Banking and Servicing		$ 12,000	$ 1,700,000	$ 1,200,000
[1]	Reported within mortgage banking income, net on the Company's consolidated statements of income.

Mortgage Banking (Schedule of M

Mortgage Banking (Schedule of Mortgage Servicing) (Details) - USD ($)		12 Months Ended
		Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Servicing Asset at Amortized Cost, Balance [Roll Forward]
Balance at beginning of year		$ 1,210,000	$ 2,161,000	$ 493,000
Capitalized servicing right fees upon sale(1)	[1]	22,000	9,000	294,000
Amortization charged against mortgage servicing fee income(1)	[1]	(430,000)	(734,000)	(231,000)
Valuation adjustment		223,000	226,000	3,000
Balance at end of year		1,025,000	1,210,000	2,161,000
Valuation Allowance:
Balance at beginning of year		(230,000)	(4,000)	(1,000)
(Increase) decrease in impairment reserve(1)	[1]	223,000	(226,000)	(3,000)
Balance at end of year		(7,000)	(230,000)	(4,000)
Fair value, beginning of year		1,701,000	2,947,000	1,447,000
Fair value, end of year		1,766,000	1,701,000	2,947,000
SBM Financial, Inc. [Member]
Servicing Asset at Amortized Cost, Balance [Roll Forward]
Capitalized servicing right fees upon sale(1)		$ 0	$ 0	$ 1,608,000
[1]	Reported within mortgage banking income, net on the Company's consolidated statements of income.

Deposits (Details)

Deposits (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Deposit [Line Items]
2,018	$ 239,936,000
2,019	110,867,000
2,020	69,944,000
2,021	32,208,000
2,022	19,816,000
Thereafter	9,239,000
Total certificates of deposit	482,010,000
FDIC Insurance Limit	250,000
Time Deposits, $250,000 or more	137,100,000	$ 104,500,000
Deposits from certain officers, directors, and their associated companies	$ 14,900,000	$ 14,400,000
Deposit Liabilities, Collateral Issued, Description	434.6	377.9
Deposit Liabilities Reclassified as Loans Receivable	$ 897,000	$ 986,000
Retail [Member]
Deposit [Line Items]
2,018	239,936,000
2,019	110,867,000
2,020	62,944,000
2,021	32,208,000
2,022	19,816,000
Thereafter	9,239,000
Total certificates of deposit	475,010,000
Brokered [Member]
Deposit [Line Items]
2,020	7,000,000
Total certificates of deposit	$ 7,000,000

Borrowings (Summary of Short te

Borrowings (Summary of Short term and Long term Borrowings and Subordinated Debentures) (Details) - USD ($) $ in Thousands		Dec. 31, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
Securities Sold under Agreements to Repurchase	[1]	$ 244,646	$ 230,612
FHLBB borrowings
Debt Instrument [Line Items]
Weighted Average Rate (as a percent)		1.87%	1.87%
Maturities of Long-term Debt and Capital Lease Obligations [Abstract]
2,018		$ 250,000
2,020		10,000
Customer repurchase agreements
Maturities of Long-term Debt and Capital Lease Obligations [Abstract]
2,018		244,646
FHLBB and correspondent bank overnight borrowings
Maturities of Long-term Debt and Capital Lease Obligations [Abstract]
2,018		47,150
Wholesale repurchase agreements
Maturities of Long-term Debt and Capital Lease Obligations [Abstract]
2,018		$ 0
Capital lease obligation
Debt Instrument [Line Items]
Weighted Average Rate (as a percent)		4.18%	4.31%
Maturities of Long-term Debt and Capital Lease Obligations [Abstract]
2,018		$ 71
2,019		76
2,020		81
2,021		90
2,022		98
Thereafter		$ 375
Long-term Debt
Debt Instrument [Line Items]
Weighted Average Rate (as a percent)		2.03%	2.05%
Maturities of Long-term Debt and Capital Lease Obligations [Abstract]
2,019		$ 76
2,020		10,081
2,021		90
2,022		98
Thereafter		375
Total long-term borrowings		$ 10,720	$ 10,791
Subordinated Debt and Junior Subordinated Debt
Debt Instrument [Line Items]
Weighted Average Rate (as a percent)		5.66%	5.69%
Maturities of Long-term Debt and Capital Lease Obligations [Abstract]
Thereafter		$ 58,911
Total long-term borrowings		$ 58,911	$ 58,755
Subordinated Debt | Subordinated debentures
Debt Instrument [Line Items]
Weighted Average Rate (as a percent)		5.50%	5.50%
Maturities of Long-term Debt and Capital Lease Obligations [Abstract]
Thereafter		$ 14,580
Total long-term borrowings		14,580	$ 14,526
Debt Issuance Costs, Net		420	474
Short-term Debt
Debt Instrument [Line Items]
Total short-term borrowings		$ 541,867	$ 530,129
Weighted Average Rate (as a percent)		1.10%	0.74%
Maturities of Long-term Debt and Capital Lease Obligations [Abstract]
2,018		$ 541,867
Short-term Debt | FHLBB borrowings
Debt Instrument [Line Items]
FHLBB borrowings		250,000	$ 210,000
Short-term Debt | Customer repurchase agreements
Debt Instrument [Line Items]
Securities Sold under Agreements to Repurchase		244,646	225,605
Short-term Debt | FHLBB and correspondent bank overnight borrowings
Debt Instrument [Line Items]
FHLBB and correspondent bank overnight borrowings		47,150	89,450
Short-term Debt | Capital lease obligation
Debt Instrument [Line Items]
Capital lease obligation		71	67
Long-term Debt
Maturities of Long-term Debt and Capital Lease Obligations [Abstract]
Long-term Federal Home Loan Bank Advances		10,000
Long-term Debt | FHLBB borrowings
Maturities of Long-term Debt and Capital Lease Obligations [Abstract]
Long-term Federal Home Loan Bank Advances		10,000	10,000
Long-term Debt | Capital lease obligation
Maturities of Long-term Debt and Capital Lease Obligations [Abstract]
Capital lease obligation		720	791
Commercial and Industrial Sector [Member] | Short-term Debt | Wholesale repurchase agreements
Debt Instrument [Line Items]
Securities Sold under Agreements to Repurchase		$ 0	$ 5,007
Subsidiary One [Member] | Junior Subordinated Debt
Debt Instrument [Line Items]
Weighted Average Rate (as a percent)		5.48%	5.50%
Maturities of Long-term Debt and Capital Lease Obligations [Abstract]
Thereafter		$ 36,083
Total long-term borrowings		$ 36,083	$ 36,083
Subsidiary Two [Member] | Junior Subordinated Debt
Debt Instrument [Line Items]
Weighted Average Rate (as a percent)		6.75%	6.85%
Maturities of Long-term Debt and Capital Lease Obligations [Abstract]
Thereafter		$ 8,248
Total long-term borrowings		$ 8,248	$ 8,146
[1]	(1) Presented within short-term borrowings on the consolidated statements of condition.

Borrowings (Additional Informat

Borrowings (Additional Information) (Details) - USD ($)		12 Months Ended
		Dec. 31, 2017	Dec. 31, 2016
Short-term Debt [Line Items]
Line of credit, maximum borrowing capacity		$ 10,000,000
Line of credit, amount outstanding		$ 0
Line of credit, expiration date		Dec. 20, 2018
Loans Pledged as Collateral		$ 144,400,000
Available-for-sale Securities Pledged as Collateral		31,000
Securities Sold under Agreements to Repurchase	[1]	244,646,000	$ 230,612,000
Amortization of Debt Issuance Costs		54,000
Federal Home Loan Bank Advances [Member]
Short-term Debt [Line Items]
Line of credit, maximum borrowing capacity		9,900,000	9,900,000
Line of credit, amount outstanding		0	$ 0
PNC [Member]
Short-term Debt [Line Items]
Line of credit, maximum borrowing capacity		50,000,000
Federal Reserve Bank Advances [Member]
Short-term Debt [Line Items]
Line of credit, maximum borrowing capacity		$ 99,800,000
Short Term Borrowing Maturing January 2017 [Member] | Short-term Debt | Minimum [Member]
Short-term Debt [Line Items]
Federal Home Loan Bank Advances Maturities Summary Fixed Interest Rate Within One Year From Balance Sheet Date		1.45%
Short Term Borrowing Maturing January 2017 [Member] | Short-term Debt | Maximum [Member]
Short-term Debt [Line Items]
Federal Home Loan Bank Advances Maturities Summary Fixed Interest Rate Within One Year From Balance Sheet Date		1.63%
[1]	(1) Presented within short-term borrowings on the consolidated statements of condition.

Borrowings (Schedule of Advance

Borrowings (Schedule of Advances to the Federal Home Loan Bank) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Maturity Schedule Of Federal Home Loan Bank Advances [Line Items]
FHLB advances, carrying value of residential real estate and commercial loans pledged as collateral	$ 1,100,000
FHLB advances, securities pledged as collateral	215	$ 400
Long-term Debt
Maturity Schedule Of Federal Home Loan Bank Advances [Line Items]
Long-term Federal Home Loan Bank Advances	$ 10,000
Long term borrowings interest rate (as a percent)	1.87%
Short Term Borrowing Maturing January 2017 [Member] | Short-term Debt
Maturity Schedule Of Federal Home Loan Bank Advances [Line Items]
FHLBB borrowings	$ 200,000
Short Term Borrowing Maturing January 2017 [Member] | Short-term Debt | Minimum [Member]
Maturity Schedule Of Federal Home Loan Bank Advances [Line Items]
Federal Home Loan Bank Advances Maturities Summary Fixed Interest Rate Within One Year From Balance Sheet Date	1.45%
Short Term Borrowing Maturing January 2017 [Member] | Short-term Debt | Maximum [Member]
Maturity Schedule Of Federal Home Loan Bank Advances [Line Items]
Federal Home Loan Bank Advances Maturities Summary Fixed Interest Rate Within One Year From Balance Sheet Date	1.63%
Federal Home Loan Bank, Advances, Callable Option [Member] | Short-term Debt
Maturity Schedule Of Federal Home Loan Bank Advances [Line Items]
FHLBB borrowings	$ 50,000
Federal Home Loan Bank Advances Maturities Summary Fixed Interest Rate Within One Year From Balance Sheet Date	1.54%

Borrowings (Subordinated Debent

Borrowings (Subordinated Debentures) (Details) - USD ($)	Oct. 08, 2015	Apr. 30, 2006	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2006	Dec. 31, 2008
Debt Instrument [Line Items]
Subordinated Debt	$ 15,000,000		$ 58,911,000	$ 58,755,000
Subordinated Borrowing, Interest Rate	5.50%
Debt Instrument, Term	10 years		10 years
Debt Instrument, Frequency of Periodic Payment			semi-annually
Debt Instrument, Maturity Date			Oct. 15, 2020
Debt Instrument, Call Date, Earliest			Oct. 15, 2025
Payments of Debt Issuance Costs			$ 536,000
Debt Issuance Cost			54,000
Value of trust preferred securities included in Tier I Capital	$ 43,000,000		43,000,000
Interest Expense, Junior Subordinated Debentures			3,408,000	3,415,000	$ 2,724,000
Junior Subordinated Debt
Debt Instrument [Line Items]
Value of trust preferred securities included in Tier I Capital			$ 43,000,000
Percentage of trust preferred securities included in Tier I Capital ratio			12.00%
Junior Subordinated Debt | Subsidiary One [Member]
Debt Instrument [Line Items]
Proceeds from issuance of trust preferred securities		$ 36,100,000
Value of outstanding common shares of subsidiary owned by company		$ 1,100,000
Debt instrument, interest rate		6.71%
Debt instrument, interest rate terms		now floats at the 3 month LIBOR plus 140 basis points
Debt interest rate, additional rate over three month LIBOR		1.40%
Junior Subordinated Debt | Subsidiary Two [Member]
Debt Instrument [Line Items]
Debt Instrument, Term						30 years
Value of outstanding common shares of subsidiary owned by company						$ 248,000
Debt instrument, interest rate terms						The interest rate of the trust preferred securities until April 7, 2011 was a blended rate equal to the sum of (1) the product of 50% times the average three-month LIBOR plus 1.42%, plus (2) the product of 50% times 6.4725%. The rate is now the average three-month LIBOR plus 1.42%.
Trust preferred securities assumed in acquisition							$ 8,000,000
Debt interest rate, additional rate over three month LIBOR						1.42%
Aggregate amount of junior subordinated debt issued to subsidiary by acquired company, prior to acquisition						$ 8,200,000
Debt instrument fixed rate						6.4725%
interest rate multiplier applied to variable rate						50.00%
interest rate multiplier applied to fixed rate						50.00%
Interest rate swaps
Debt Instrument [Line Items]
Notional amount of derivative			$ 43,000,000	$ 43,000,000

Repurchase Agreements (Details)

Repurchase Agreements (Details) - USD ($) $ in Thousands		Dec. 31, 2017	Dec. 31, 2016
Assets Sold under Agreements to Repurchase [Line Items]
Securities Sold under Agreements to Repurchase	[1]	$ 244,646	$ 230,612
Certificates of Deposit, at Carrying Value		920	917
Overnight and Continuous
Assets Sold under Agreements to Repurchase [Line Items]
Securities Sold under Agreements to Repurchase	[1]	244,646	225,605
Up to 30 Days
Assets Sold under Agreements to Repurchase [Line Items]
Securities Sold under Agreements to Repurchase	[1]	0	0
30 - 90 Days
Assets Sold under Agreements to Repurchase [Line Items]
Securities Sold under Agreements to Repurchase	[1]	0	5,007
Greater than 90 Days
Assets Sold under Agreements to Repurchase [Line Items]
Securities Sold under Agreements to Repurchase	[1]	0	0
Commercial Borrower
Assets Sold under Agreements to Repurchase [Line Items]
Securities Sold under Agreements to Repurchase			5,007
Commercial Borrower | Overnight and Continuous
Assets Sold under Agreements to Repurchase [Line Items]
Securities Sold under Agreements to Repurchase			0
Commercial Borrower | Up to 30 Days
Assets Sold under Agreements to Repurchase [Line Items]
Securities Sold under Agreements to Repurchase			0
Commercial Borrower | 30 - 90 Days
Assets Sold under Agreements to Repurchase [Line Items]
Securities Sold under Agreements to Repurchase			5,007
Commercial Borrower | Greater than 90 Days
Assets Sold under Agreements to Repurchase [Line Items]
Securities Sold under Agreements to Repurchase			0
Commercial Borrower | Mortgage-backed securities issued or guaranteed by U.S. government sponsored enterprises [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Securities Sold under Agreements to Repurchase			3,715
Commercial Borrower | Mortgage-backed securities issued or guaranteed by U.S. government sponsored enterprises [Member] | Overnight and Continuous
Assets Sold under Agreements to Repurchase [Line Items]
Securities Sold under Agreements to Repurchase			0
Commercial Borrower | Mortgage-backed securities issued or guaranteed by U.S. government sponsored enterprises [Member] | Up to 30 Days
Assets Sold under Agreements to Repurchase [Line Items]
Securities Sold under Agreements to Repurchase			0
Commercial Borrower | Mortgage-backed securities issued or guaranteed by U.S. government sponsored enterprises [Member] | 30 - 90 Days
Assets Sold under Agreements to Repurchase [Line Items]
Securities Sold under Agreements to Repurchase			3,715
Commercial Borrower | Mortgage-backed securities issued or guaranteed by U.S. government sponsored enterprises [Member] | Greater than 90 Days
Assets Sold under Agreements to Repurchase [Line Items]
Securities Sold under Agreements to Repurchase			0
Commercial Borrower | Collateralized mortgage obligations issued or guaranteed by U.S. government sponsored enterprises [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Securities Sold under Agreements to Repurchase			1,292
Commercial Borrower | Collateralized mortgage obligations issued or guaranteed by U.S. government sponsored enterprises [Member] | Overnight and Continuous
Assets Sold under Agreements to Repurchase [Line Items]
Securities Sold under Agreements to Repurchase			0
Commercial Borrower | Collateralized mortgage obligations issued or guaranteed by U.S. government sponsored enterprises [Member] | Up to 30 Days
Assets Sold under Agreements to Repurchase [Line Items]
Securities Sold under Agreements to Repurchase			0
Commercial Borrower | Collateralized mortgage obligations issued or guaranteed by U.S. government sponsored enterprises [Member] | 30 - 90 Days
Assets Sold under Agreements to Repurchase [Line Items]
Securities Sold under Agreements to Repurchase			1,292
Commercial Borrower | Collateralized mortgage obligations issued or guaranteed by U.S. government sponsored enterprises [Member] | Greater than 90 Days
Assets Sold under Agreements to Repurchase [Line Items]
Securities Sold under Agreements to Repurchase			0
Retail [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Securities Sold under Agreements to Repurchase		244,646	225,605
Retail [Member] | Overnight and Continuous
Assets Sold under Agreements to Repurchase [Line Items]
Securities Sold under Agreements to Repurchase		244,646	225,605
Retail [Member] | Up to 30 Days
Assets Sold under Agreements to Repurchase [Line Items]
Securities Sold under Agreements to Repurchase		0	0
Retail [Member] | 30 - 90 Days
Assets Sold under Agreements to Repurchase [Line Items]
Securities Sold under Agreements to Repurchase		0	0
Retail [Member] | Greater than 90 Days
Assets Sold under Agreements to Repurchase [Line Items]
Securities Sold under Agreements to Repurchase		0	0
Retail [Member] | Mortgage-backed securities issued or guaranteed by U.S. government sponsored enterprises [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Securities Sold under Agreements to Repurchase		98,460	117,784
Retail [Member] | Mortgage-backed securities issued or guaranteed by U.S. government sponsored enterprises [Member] | Overnight and Continuous
Assets Sold under Agreements to Repurchase [Line Items]
Securities Sold under Agreements to Repurchase		98,460	117,784
Retail [Member] | Mortgage-backed securities issued or guaranteed by U.S. government sponsored enterprises [Member] | Up to 30 Days
Assets Sold under Agreements to Repurchase [Line Items]
Securities Sold under Agreements to Repurchase		0	0
Retail [Member] | Mortgage-backed securities issued or guaranteed by U.S. government sponsored enterprises [Member] | 30 - 90 Days
Assets Sold under Agreements to Repurchase [Line Items]
Securities Sold under Agreements to Repurchase		0	0
Retail [Member] | Mortgage-backed securities issued or guaranteed by U.S. government sponsored enterprises [Member] | Greater than 90 Days
Assets Sold under Agreements to Repurchase [Line Items]
Securities Sold under Agreements to Repurchase		0	0
Retail [Member] | Collateralized mortgage obligations issued or guaranteed by U.S. government sponsored enterprises [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Securities Sold under Agreements to Repurchase		145,556	107,821
Retail [Member] | Collateralized mortgage obligations issued or guaranteed by U.S. government sponsored enterprises [Member] | Overnight and Continuous
Assets Sold under Agreements to Repurchase [Line Items]
Securities Sold under Agreements to Repurchase		145,556	107,821
Retail [Member] | Collateralized mortgage obligations issued or guaranteed by U.S. government sponsored enterprises [Member] | Up to 30 Days
Assets Sold under Agreements to Repurchase [Line Items]
Securities Sold under Agreements to Repurchase		0	0
Retail [Member] | Collateralized mortgage obligations issued or guaranteed by U.S. government sponsored enterprises [Member] | 30 - 90 Days
Assets Sold under Agreements to Repurchase [Line Items]
Securities Sold under Agreements to Repurchase		0	0
Retail [Member] | Collateralized mortgage obligations issued or guaranteed by U.S. government sponsored enterprises [Member] | Greater than 90 Days
Assets Sold under Agreements to Repurchase [Line Items]
Securities Sold under Agreements to Repurchase		0	$ 0
Retail [Member] | Obligations of states and political subdivisions [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Securities Sold under Agreements to Repurchase		630
Retail [Member] | Obligations of states and political subdivisions [Member] | Overnight and Continuous
Assets Sold under Agreements to Repurchase [Line Items]
Securities Sold under Agreements to Repurchase		630
Retail [Member] | Obligations of states and political subdivisions [Member] | Up to 30 Days
Assets Sold under Agreements to Repurchase [Line Items]
Securities Sold under Agreements to Repurchase		0
Retail [Member] | Obligations of states and political subdivisions [Member] | 30 - 90 Days
Assets Sold under Agreements to Repurchase [Line Items]
Securities Sold under Agreements to Repurchase		0
Retail [Member] | Obligations of states and political subdivisions [Member] | Greater than 90 Days
Assets Sold under Agreements to Repurchase [Line Items]
Securities Sold under Agreements to Repurchase		$ 0
[1]	(1) Presented within short-term borrowings on the consolidated statements of condition.

Income Taxes (Schedule of Incom

Income Taxes (Schedule of Income Tax Expense) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Current:
Federal									$ 14,529	$ 17,854	$ 7,956
State									1,289	930	71
Total									15,818	18,784	8,027
Deferred:
Change in federal corporate income tax rate(1)									14,263	0	0
Federal									4,117	(1,258)	1,356
Deferred State and Local Income Tax Expense (Benefit)									(320)	(54)	524
Deferred Income Tax Expense (Benefit)									18,060	(1,312)	1,880
Income tax expense	$ 19,335	$ 5,478	$ 4,721	$ 4,344	$ 4,730	$ 5,042	$ 4,258	$ 3,442	$ 33,878	$ 17,472	$ 9,907

Income Taxes (Reconciliation of

Income Taxes (Reconciliation of Expected Income Tax Benefit Computed Using Federal Statutory Income Tax Rate) (Details) - USD ($) $ in Thousands		3 Months Ended								12 Months Ended
		Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Computed tax expense										$ 21,824	$ 20,139	$ 10,801
Change in federal corporate income tax rate										14,263	0	0
Tax exempt income										(1,291)	(1,312)	(1,092)
Income from life insurance										(829)	(908)	(588)
State taxes, net of federal benefit										630	565	373
Share-based awards(1)	[1]									(390)	(701)	0
Low income housing credits										(366)	(376)	(359)
Non-deductible acquisition-related costs										0	0	467
Other										37	65	305
Income tax expense		$ 19,335	$ 5,478	$ 4,721	$ 4,344	$ 4,730	$ 5,042	$ 4,258	$ 3,442	33,878	17,472	9,907
Income before income taxes		$ 16,162	$ 16,817	$ 14,955	$ 14,420	$ 15,632	$ 15,945	$ 13,874	$ 12,088	$ 62,354	$ 57,539	$ 30,859
Effective tax rate										54.30%	30.40%	32.10%
[1]	(1) The Company adopted the provisions of ASU 2016-09, Compensation—Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting, in calendar year 2016. Prior to adoption, it accounted for its windfall tax benefits or shortfalls generated upon exercise of a non-qualified stock option or a disqualifying incentive stock option, or upon vesting of its restricted shares through shareholders' equity (or as income tax expense to the extent the Company did not have a windfall tax benefit surplus). Upon adoption, the Company now accounts for its windfall tax benefits and shortfalls generated within income tax expense on the consolidated statements of income as a discrete period item in the quarter generated.

Income Taxes (Schedule of Defer

Income Taxes (Schedule of Deferred Tax Assets and Deferred Tax Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Asset
Net operating loss and tax credit carryforward	$ 12,078	$ 20,977
Allowance for loan losses	5,201	8,094
Pension and other benefits	3,363	5,141
Net unrealized losses on AFS securities	2,821	3,227
Net unrealized losses on derivative instruments	1,623	3,066
Deferred compensation and benefits	1,199	1,791
Net unrealized losses on postretirement plans	1,092	1,147
Purchase accounting and deposit premium	461	1,430
Total	27,838	45,829
Liability
Depreciation	(2,857)	(4,520)
Deferred loan origination fees	(1,510)	(2,046)
Other		(956)
Deferred Tax Liabilities, Other	695
Total	(5,062)	(6,566)
Income Tax Contingency [Line Items]
Deferred Tax Assets, Net of Valuation Allowance	$ 22,776	$ 39,263

Income Taxes (Additional Inform

Income Taxes (Additional Information) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Oct. 16, 2016	Oct. 16, 2015
Income Tax Contingency [Line Items]
Change in federal corporate income tax rate	$ 14,263,000	$ 0	$ 0
Operating Loss Carryforwards		$ 803,000		$ 3,900,000
Domestic Tax Authority [Member]
Income Tax Contingency [Line Items]
Operating Loss Carryforwards				6,800,000
SBM Financial, Inc. [Member] | Domestic Tax Authority [Member]
Income Tax Contingency [Line Items]
Operating Loss Carryforwards				71,200,000
Operating Loss Carryforwards, Valuation Allowance					$ 0
SBM Financial, Inc. [Member] | State and Local Jurisdiction [Member]
Income Tax Contingency [Line Items]
Operating Loss Carryforwards				$ 213,000
Minimum [Member]
Income Tax Contingency [Line Items]
Operating Loss Carryforwards, Expiration Date	Dec. 31, 2030
Maximum [Member]
Income Tax Contingency [Line Items]
Operating Loss Carryforwards, Expiration Date	Dec. 31, 2034

Shareholders' Equity (Details)

Shareholders' Equity (Details) - USD ($) $ in Thousands	Oct. 08, 2015	Dec. 31, 2017	Dec. 31, 2016
Total risk-based capital:
Actual Regulatory Capital - Amount		$ 396,451	$ 368,856
Capital To Risk Weighted Assets		14.14%	14.04%
Minimum Requirement for capital Adequacy Including Capital Buffer Total Risk-Based Capital Ratio		9.25%
Minimum Regulatory Capital Required - Ratio		8.00%	8.63%
Tier 1 capital:
Actual Regulatory Capital - Amount		$ 357,261	$ 330,729
Actual Regulatory Capital - Ratio		12.74%	12.59%
Minimum Requirement for capital Adequacy Including Capital Buffer Tier I Risk-Based Capital Ratio		7.25%
Minimum Regulatory Capital Required - Ratio		6.00%	6.63%
Common equity tier I capital		$ 316,677	$ 296,120
Tier 1 leverage capital ratio:
Actual Regulatory Capital - Amount		$ 357,261	$ 330,729
Actual Regulatory Capital - Ratio		9.07%	8.83%
Minimum Regulatory Capital Required - Ratio		4.00%	4.00%
Common Equity Tier I Risk Based Capital Ratio		11.30%	11.27%
Minimum Requirement for capital Adequacy Including Capital Buffer Common Equity Tier I Risk-Based Capital Ratio		5.75%
Common Equity Tier One Risk Based Capital Required for Capital Adequacy to Risk Weighted Assets		4.50%	5.13%
Capital Conservation Buffer		2.50%
Value Of Trust Preferred Securities Included In Tier One Capital	$ 43,000	$ 43,000
Subordinated Debt	$ 15,000	$ 58,911	$ 58,755
Debt Instrument, Term	10 years	10 years
Subordinated Borrowing, Interest Rate	5.50%
Subsidiaries [Member]
Total risk-based capital:
Actual Regulatory Capital - Amount		$ 369,540	$ 340,908
Capital To Risk Weighted Assets		13.18%	12.92%
Minimum Requirement for capital Adequacy Including Capital Buffer Total Risk-Based Capital Ratio		9.25%
Minimum Regulatory Capital Required - Ratio			8.63%
Minimum Regulatory Provision To Be Well Capitalized - Ratio		10.00%	10.00%
Tier 1 capital:
Actual Regulatory Capital - Amount		$ 345,350	$ 317,782
Actual Regulatory Capital - Ratio		12.32%	12.05%
Minimum Requirement for capital Adequacy Including Capital Buffer Tier I Risk-Based Capital Ratio		7.25%
Minimum Regulatory Capital Required - Ratio			6.63%
Minimum Regulatory Provision To Be Well Capitalized - Ratio		8.00%	8.00%
Common equity tier I capital		$ 345,350	$ 317,782
Tier 1 leverage capital ratio:
Actual Regulatory Capital - Amount		$ 345,350	$ 317,782
Actual Regulatory Capital - Ratio		8.80%	8.54%
Minimum Regulatory Capital Required - Ratio		4.00%	4.00%
Minimum Regulatory Provision To Be Well Capitalized - Ratio		5.00%	5.00%
Common Equity Tier I Risk Based Capital Ratio		12.32%	12.05%
Minimum Requirement for capital Adequacy Including Capital Buffer Common Equity Tier I Risk-Based Capital Ratio		5.75%
Common Equity Tier One Risk Based Capital Required for Capital Adequacy to Risk Weighted Assets			5.13%
Common Equity Tier One Risk Based Capital Required to be Well Capitalized to Risk Weighted Assets		6.50%	6.50%
Tier II Capital [Domain]
Tier 1 leverage capital ratio:
Subordinated Debt		$ 15,000
Minimum [Member]
Tier 1 leverage capital ratio:
Capital Conservation Buffer		1.25%

Shareholders' Equity (Narrative

Shareholders' Equity (Narrative) (Details)	Sep. 14, 2016USD ($)$ / shares	Sep. 30, 2016	Dec. 31, 2017USD ($)$ / sharesshares	Dec. 31, 2016USD ($)shares	Dec. 31, 2015USD ($)	Oct. 16, 2015$ / shares	Sep. 24, 2013shares
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
number of years			2
Dividends declared to shareholders			$ 14,600,000	$ 12,900,000	$ 10,600,000
Stockholders' Equity Note, Stock Split Ratio, Numerator | shares				1
Stockholders' Equity Note, Stock Split Ratio, Denominator | shares				2
Share Price | $ / shares	$ 31.75
Stockholders' Equity Note, Stock Split, Reduction of Capital	$ 5,000			$ (5,000)
Stockholders' Equity Note, Stock Split, Conversion Ratio		1.5	1.5
Acadia Trust [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Dividends declared to shareholders					0
Subsidiaries [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Dividends declared to shareholders			$ 16,800,000	$ 16,000,000	$ 39,200,000
2012 Common Stock Repurchase Program [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Stock repurchase program, shares of common stock approved for repurchase | shares							375,000
Stock repurchased during period, shares | shares			0	374,250
Shares repurchased, average cost per share | $ / shares			$ 26.55
The percentage of the stock repurchase program's allotment repurchased during the period			99.80%
SBM Financial, Inc. [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Share Price | $ / shares						$ 26.32
SBM Financial, Inc. [Member] | Subsidiaries [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Dividends declared to shareholders				$ 30,000,000

Earnings per Share (Computation

Earnings per Share (Computation of Basic and Diluted Earnings Per Share) (Details) $ / shares in Units, $ in Thousands		3 Months Ended								9 Months Ended	12 Months Ended
		Dec. 31, 2017USD ($)$ / shares	Sep. 30, 2017USD ($)$ / shares	Jun. 30, 2017USD ($)$ / shares	Mar. 31, 2017USD ($)$ / shares	Dec. 31, 2016USD ($)$ / shares	Sep. 30, 2016USD ($)$ / shares	Jun. 30, 2016USD ($)$ / shares	Mar. 31, 2016USD ($)$ / shares	Sep. 30, 2016	Dec. 31, 2017USD ($)$ / sharesshares	Dec. 31, 2016USD ($)$ / sharesshares	Dec. 31, 2015USD ($)$ / sharesshares
Earnings Per Share, Basic and Diluted, Other Disclosures [Abstract]
Net income | $		$ (3,173)	$ 11,339	$ 10,234	$ 10,076	$ 10,902	$ 10,903	$ 9,616	$ 8,646		$ 28,476	$ 40,067	$ 20,952
Dividends and undistributed earnings allocated to participating securities(1) | $	[1]										(118)	(189)	(59)
Net income available to common shareholders | $											$ 28,358	$ 39,878	$ 20,893
Weighted-average common shares outstanding for basic EPS											15,509,665	15,422,160	12,031,294
Dilutive effect of stock-based awards	[2]										78,682	82,079	43,285
Weighted-average common and potential common shares for diluted EPS											15,588,347	15,504,239	12,074,579
Basic EPS | $ / shares		$ (0.20)	$ 0.72	$ 0.66	$ 0.65	$ 0.70	$ 0.70	$ 0.62	$ 0.56		$ 1.83	$ 2.59	$ 1.73
Diluted EPS | $ / shares		$ (0.20)	$ 0.72	$ 0.66	$ 0.64	$ 0.70	$ 0.70	$ 0.62	$ 0.56		$ 1.82	$ 2.57	$ 1.73
Shares that were not considered in computation of potential common shares for purposes of diluted EPS	[3]										0	0	19,875
Stockholders' Equity Note, Stock Split, Conversion Ratio										1.5	1.5
[1]	Represents dividends paid and undistributed earnings allocated to nonvested stock-based awards that contain non-forfeitable rights to dividends.
[2]	Represents the effect of the assumed exercise of stock options, and vesting of restricted shares and restricted stock units, and issuance of LTIP awards that have met the performance criteria, utilizing the treasury stock method.
[3]	Represents stock-based awards not included in the computation of potential common shares for purposes of calculating diluted EPS as the exercise prices were greater than the average market price of the Company's common stock, and, therefore, are considered anti-dilutive.

Stock-Based Compensation Plan94

Stock-Based Compensation Plans (Additional Information) (Details) - USD ($)	May 01, 2012	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Cash used to settle stock based compensation transactions		$ 902,000	$ 373,000	$ 157,000
Cash received from exercise of stock options		$ 98,000	$ 1,300,000	$ 736,000
Performance period		0 years	5 years 3 months 18 days	5 years 3 months 18 days
Percentage of total compensation		4.00%
Stock Option and Incentive Plan 2003 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum number of shares of stock reserved and available for issuance	1,200,000
Stock Option and Incentive Plan 2012 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock based compensation, option granted, contractual life		10 years
Stock based compensation, vesting period		5 years
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grant date fair value of share based awards		$ 0	$ 16,000	$ 22,000
Share-based compensation		20,000	30,000	51,000
Tax benefit from share based compensation		21,000	36,000	59,000
Unrecognized compensation cost for nonvested stock options		$ 41,000
Unrecognized compensation cost, recognition period		2 years 3 months
Total intrinsic value of options exercised		$ 268,000	2,500,000	573,000
Stock Options [Member] | SBM Financial, Inc. [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Tax benefit from share based compensation		21,000	378,000	0
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grant date fair value of share based awards		808,000	0	0
Share-based compensation		124,000	0	0
Tax benefit from share based compensation		27,000	0	0
Unrecognized compensation cost related to nonvested shares		$ 620,000
Granted		18,762
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grant date fair value of share based awards		$ 686,000	925,000	1,000,000
Share-based compensation		762,000	703,000	327,000
Tax benefit from share based compensation		164,000	246,000	114,000
Total intrinsic value of options exercised		697,000	502,000	0
Unrecognized compensation cost related to nonvested shares		$ 787,000
Granted		16,185
Management Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise price as a percentage of fair market value on the date of grant		0.00%
Stock based compensation, vesting period		2 years
Grant date fair value of share based awards		$ 111,000	128,000	108,000
Share-based compensation		97,000	102,000	66,000
Tax benefit from share based compensation		21,000	36,000	23,000
Cash received from issuance of share based awards		180,000	241,000	220,000
Unrecognized compensation cost related to nonvested shares		$ 54,000
Granted		8,088
Management Stock Purchase Plan [Member] | Interest and Other Liabilities [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Cash received from issuance of share based awards		$ 421,000	454,000
Long-Term Performance Share Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation		370,000	1,080,000	330,000
Tax benefit from share based compensation		80,000	378,000	116,000
Total intrinsic value of options exercised		$ 697,000	502,000	963,000
Performance period		3 years
Unrecognized compensation cost related to nonvested shares		$ 291,000
Granted		16,830
Deferred Stock Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grant date fair value of share based awards		$ 118,000	111,000	93,000
Share-based compensation		97,000	81,000	62,000
Tax benefit from share based compensation		$ 21,000	$ 28,000	$ 22,000
Percentage of total compensation		10.00%
Percentage vested on 65th birthday		100.00%
Qualified Stock Options [Member] | Stock Option and Incentive Plan 2012 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise price as a percentage of fair market value on the date of grant	100.00%
Nonqualified Stock Options [Member] | Stock Option and Incentive Plan 2012 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise price as a percentage of fair market value on the date of grant	85.00%

Stock-Based Compensation Plan95

Stock-Based Compensation Plans (Schedule of Option Pricing Assumptions and Estimated Fair Value) (Details) - $ / shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Weighted-average dividend yield	0.00%	3.12%	3.01%
Weighted-average risk-free interest rate	0.00%	1.52%	1.50%
Weighted-average expected volatility	0.00%	29.64%	31.85%
Weighted-average expected life (in years)	0 years	5 years 3 months 18 days	5 years 3 months 18 days
Weighted-average fair value of options granted	$ 0	$ 5.17	$ 5.87

Stock-Based Compensation Plan96

Stock-Based Compensation Plans (Schedule of Stock Option Activity) (Details) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2017USD ($)$ / sharesshares
Number of Shares
Options outstanding, beginning | shares	58,743
Granted | shares	0
Exercised | shares	(11,841)
Forfeited | shares	(2,400)
Expired | shares	1,425
Options outstanding, ending | shares	43,077
Options exercisable | shares	39,627
Weighted Average Exercise Price Per Share
Options outstanding, beginning | $ / shares	$ 20.38
Granted | $ / shares	0
Exercised | $ / shares	17.50
Forfeited | $ / shares	26.23
Expired | $ / shares	23.11
Options outstanding, ending | $ / shares	21
Options exercisable | $ / shares	$ 20.58
Weighted- Average Remaining Contractual Term
Options outstanding	3 years 5 months 12 days
Options exercisable	3 years 1 month 8 days
Aggregate Intrinsic Value
Options outstanding | $	$ 910
Options exercisable | $	$ 854

Stock-Based Compensation Plan97

Stock-Based Compensation Plans (Summary of Nonvested Stock Options) (Details) - $ / shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Awards
Nonvested, beginning	9,450
Granted	0
Vested	(3,600)
Forfeited	(2,400)
Nonvested, ending	3,450	9,450
Weighted- Average Grant Date Fair Value
Nonvested, beginning	$ 6.59
Granted	0	$ 5.17	$ 5.87
Vested	7.80
Forfeited	5.48
Nonvested, ending	$ 6.11	$ 6.59

Stock-Based Compensation Plan98

Stock-Based Compensation Plans (Schedule of Compensation Expense) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Restricted Stock Units (RSUs) [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Compensation expense(1)	$ 124	$ 0	$ 0
Income tax benefit	27	0	0
Fair value of grants vested	0	0	0
Restricted Stock [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Compensation expense(1)	762	703	327
Income tax benefit	164	246	114
Fair value of grants vested	702	603	341
Management Stock Purchase Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Compensation expense(1)	97	102	66
Income tax benefit	21	36	23
Fair value of grants vested	91	57	92
Performance Shares [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Compensation expense(1)	370	1,080	330
Income tax benefit	80	378	116
Fair value of grants vested	843	725	412
Deferred Stock Awards [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Compensation expense(1)	97	81	62
Income tax benefit	21	28	22
Fair value of grants vested	$ 90	$ 75	$ 59

Stock-Based Compensation Plan99

Stock-Based Compensation Plans (Summary of Activity Related to Share Based Awards) (Details) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2017USD ($)$ / sharesshares
Restricted Stock Units (RSUs) [Member]
Number of Shares
Nonvested, beginning | shares	0
Granted | shares	18,762
Vested | shares	0
Forfeited | shares	(1,285)
Nonvested, ending | shares	17,477
Weighted Average Grant Date Fair Value
Nonvested, beginning | $ / shares	$ 0
Granted | $ / shares	43.05
Vested | $ / shares	0
Forfeited | $ / shares	43.11
Nonvested, ending | $ / shares	$ 43.04
Weighted-Average Remaining Contractual Term (Years)
Nonvested, weighted average remaining contractual term	4 years 7 months 6 days
Aggregate Intrinsic Value
Nonvested, aggregate intrinsic value | $	$ 736
Unrecognized Compensation
Nonvested, unrecognized compensation | $	$ 620
Restricted Stock [Member]
Number of Shares
Nonvested, beginning | shares	47,518
Granted | shares	16,185
Vested | shares	(22,553)
Forfeited | shares	(4,825)
Nonvested, ending | shares	36,325
Weighted Average Grant Date Fair Value
Nonvested, beginning | $ / shares	$ 28.16
Granted | $ / shares	42.39
Vested | $ / shares	31.14
Forfeited | $ / shares	28.93
Nonvested, ending | $ / shares	$ 32.56
Weighted-Average Remaining Contractual Term (Years)
Nonvested, weighted average remaining contractual term	2 years 2 months 12 days
Aggregate Intrinsic Value
Nonvested, aggregate intrinsic value | $	$ 1,530
Unrecognized Compensation
Nonvested, unrecognized compensation | $	$ 787
Management Stock Purchase Plan [Member]
Number of Shares
Nonvested, beginning | shares	26,699
Granted | shares	8,088
Vested | shares	(11,777)
Forfeited | shares	(2,791)
Nonvested, ending | shares	20,219
Weighted Average Grant Date Fair Value
Nonvested, beginning | $ / shares	$ 7.85
Granted | $ / shares	13.73
Vested | $ / shares	7.73
Forfeited | $ / shares	11.49
Nonvested, ending | $ / shares	$ 9.77
Weighted-Average Remaining Contractual Term (Years)
Nonvested, weighted average remaining contractual term	1 year
Aggregate Intrinsic Value
Nonvested, aggregate intrinsic value | $	$ 431
Unrecognized Compensation
Nonvested, unrecognized compensation | $	$ 54
Performance Shares [Member]
Number of Shares
Nonvested, beginning | shares	52,737
Granted | shares	16,830
Vested | shares	(32,323)
Forfeited | shares	(5,621)
Nonvested, ending | shares	31,623
Weighted Average Grant Date Fair Value
Nonvested, beginning | $ / shares	$ 27.01
Granted | $ / shares	41.39
Vested | $ / shares	26.09
Forfeited | $ / shares	26.97
Nonvested, ending | $ / shares	$ 35.60
Weighted-Average Remaining Contractual Term (Years)
Nonvested, weighted average remaining contractual term	1 year 8 months 12 days
Aggregate Intrinsic Value
Nonvested, aggregate intrinsic value | $	$ 1,332
Unrecognized Compensation
Nonvested, unrecognized compensation | $	$ 291
DCRP Awards [Member]
Number of Shares
Nonvested, beginning | shares	14,244
Granted | shares	2,772
Vested | shares	(2,776)
Forfeited | shares	(4,192)
Nonvested, ending | shares	10,048
Weighted Average Grant Date Fair Value
Nonvested, beginning | $ / shares	$ 23.65
Granted | $ / shares	42.66
Vested | $ / shares	32.50
Forfeited | $ / shares	25.88
Nonvested, ending | $ / shares	$ 25.52
Weighted-Average Remaining Contractual Term (Years)
Nonvested, weighted average remaining contractual term	9 years 2 months 12 days
Aggregate Intrinsic Value
Nonvested, aggregate intrinsic value | $	$ 423
Unrecognized Compensation
Nonvested, unrecognized compensation | $	$ 229

Employee Benefit Plans (Additio

Employee Benefit Plans (Additional Information) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
401(k)/Profit Sharing Plan
Contribution match, as a percentage of annual pay	4.00%
Contribution matches, percentage of pre-tax compensation	3.00%	3.00%	3.00%
Expenses under the 401(K)/Profit Sharing plan	$ 2,300	$ 2,200	$ 1,500
Supplemental Executive Retirement Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Minimum guaranteed benefit term	15 years
Accumulated benefit obligation	$ 12,300	$ 10,700
Expected amortization of net actuarial loss	$ 561
Supplemental Executive Retirement Plan [Member] | Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Percentage of income replaced	65.00%
Supplemental Executive Retirement Plan [Member] | Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Percentage of income replaced	75.00%
Other Postretirement Benefit Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Expected amortization of net actuarial loss	$ 53
Expected amortization of prior service cost	$ 24

Employee Benefit Plans (Schedul

Employee Benefit Plans (Schedule of Changes in Benefit Obligation and Plan Assets) (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Amounts recognized in accumulated other comprehensive loss
Total		$ 3,988	$ 2,130
Supplemental Executive Retirement Plan [Member]
Benefit obligations:
Beginning of year		11,523	11,052
Service cost		335	308	$ 307
Interest cost		452	432	424
Actuarial loss		1,955	219
Benefits paid		(475)	(488)
End of year		13,790	11,523	11,052
Fair value of plan assets:
Beginning of year		0	0
Employer contributions		475	488
Benefits paid		(475)	(488)
End of year		0	0	0
Unfunded status at end of year(1)	[1]	13,790	11,523
Amounts recognized in accumulated other comprehensive loss
Net actuarial loss		3,504	1,791
Total		3,504	1,791
Other Postretirement Benefit Plan [Member]
Benefit obligations:
Beginning of year		3,635	3,447
Service cost		53	59	62
Interest cost		144	151	117
Actuarial loss		110	143
Benefits paid		(151)	(165)
End of year		3,791	3,635	3,447
Fair value of plan assets:
Beginning of year		0	0
Employer contributions		151	165
Benefits paid		(151)	(165)
End of year		0	0	$ 0
Unfunded status at end of year(1)	[1]	3,791	3,635
Amounts recognized in accumulated other comprehensive loss
Net actuarial loss		654	495
Prior service credit		(170)	(156)
Total		$ 484	$ 339
[1]	1)Presented within other liabilities on the consolidated statements of condition.

Employee Benefit Plans (Sche102

Employee Benefit Plans (Schedule of Net Period Benefit Cost and Other Amounts Recognized in Other Comprehensive Income) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Supplemental Executive Retirement Plan [Member]
Net period benefit cost
Service cost	$ 335	$ 308	$ 307
Interest cost	452	432	424
Recognized net actuarial loss	246	220	218
Amortization of prior service cost (credit)		7	19
Net periodic benefit cost	1,033	967	968
Changes in funded status recognized in other comprehensive loss, before taxes
Net actuarial (gain) loss arising during period	1,955	219	(32)
Amortization of net unrecognized actuarial loss	(246)	(220)	(218)
Amortization of prior service (cost) credit		(7)	(19)
Total recognized in OCI, before taxes	1,709	(8)	(269)
Total recognized in net periodic benefit cost and OCI, before taxes	2,742	959	699
Other Postretirement Benefit Plan [Member]
Net period benefit cost
Service cost	53	59	62
Interest cost	144	151	117
Recognized net actuarial loss	41	30	24
Amortization of prior service cost (credit)	(24)	(22)	(22)
Net periodic benefit cost	214	218	181
Changes in funded status recognized in other comprehensive loss, before taxes
Net actuarial (gain) loss arising during period	110	143	92
Amortization of net unrecognized actuarial loss	(41)	(30)	(24)
Amortization of prior service (cost) credit	24	22	22
Total recognized in OCI, before taxes	93	135	90
Total recognized in net periodic benefit cost and OCI, before taxes	$ 307	$ 353	$ 271

Employee Benefit Plans (Sche103

Employee Benefit Plans (Schedule of Assumptions Used to Determine Benefit Obligations and Net Periodic Benefit Cost) (Details)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Supplemental Executive Retirement Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate for benefit obligation	3.60%	4.00%	4.00%
Discount rate for net periodic benefit cost	4.00%	4.00%	4.00%
Rate of compensation increase for benefit obligation	5.00%	4.00%	4.00%
Rate of compensation increase for net periodic benefit cost	5.00%	4.00%	4.00%
Other Postretirement Benefit Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate for benefit obligation	3.55%	4.00%	4.50%
Discount rate for net periodic benefit cost	4.00%	4.50%	4.00%
Health care cost trend rate assumed for future years	6.50%	7.00%	7.00%

Employee Benefit Plans (Sche104

Employee Benefit Plans (Schedule of Estimated Future Benefit Payments) (Details) $ in Thousands	Dec. 31, 2017USD ($)
Supplemental Executive Retirement Plan [Member]
Expected future benefit payments under the plans:
2,017	$ 473
2,018	477
2,019	486
2,020	536
2,021	566
2022- 2026	2,246
Other Postretirement Benefit Plan [Member]
Expected future benefit payments under the plans:
2,017	156
2,018	168
2,019	173
2,020	175
2,021	187
2022- 2026	$ 1,061

Other Non-Interest Income an105

Other Non-Interest Income and Expenses (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Other non-interest income [Line Items]
Other Income		$ 1,545	$ 4,830	$ 2,363
Other income		3,119	6,934	3,877
Employee-related costs(1)		1,852	1,660	1,841
Travel and Entertainment Expense	[1]	1,710	1,616	1,437
Postage, freight, and courier		1,655	1,754	1,430
Labor and Related Expense		49,965	48,072	37,220
Other expenses		5,731	5,657	4,502
Total		10,948	10,687	9,210
Customer loan swaps
Other non-interest income [Line Items]
Interest and Other Income		$ 1,574	$ 2,104	$ 1,514
[1]	Employee-related costs include hiring, training, education, meeting and business travel costs.

Commitments, Contingencies a106

Commitments, Contingencies and Derivatives (Additional Information) (Details)	12 Months Ended
	Dec. 31, 2017USD ($)swap	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)
Legal Proceedings [Line Items]
Loss Contingency Accrual	$ 0	$ 0
Derivative, Number of Interest Rate Swap Agreements | swap	2
Loss on Cash Flow Hedge Ineffectiveness	$ 0	0	$ 0
Unrealized Gain (Loss) on Derivatives	37,000	(289,000)
Expected reclassification of interest expense	936,000
Interest Rate Swap [Member]
Legal Proceedings [Line Items]
Notional amount of derivative	43,000,000	43,000,000
Net payments to counterparty	1,300,000	1,500,000	1,700,000
Cash held as collateral	8,100,000
Derivative, Fair Value, Net		(7,571,000)	(8,372,000)
Forward-Starting Interest Rate Swap [Member]
Legal Proceedings [Line Items]
Notional amount of derivative	50,000,000	50,000,000
Net payments to counterparty	288,000	490,000
Derivative, Fair Value, Net	21,000	(389,000)
Interest Rate Lock Commitments [Member]
Legal Proceedings [Line Items]
Notional amount of derivative	21,746,000	15,249,000
Derivative, Fair Value, Net	285,000	187,000
Unrealized Gain (Loss) on Derivatives	98,000	48,000	139,000
Forward Contracts [Member]
Legal Proceedings [Line Items]
Notional amount of derivative	8,065,000	15,125,000
Derivative, Fair Value, Net	142,000	278,000
Unrealized Gain (Loss) on Derivatives	(136,000)	278,000	$ 0
Loans [Member] | Interest Rate Swap [Member]
Legal Proceedings [Line Items]
Notional amount of derivative	703,336,000	532,526,000
Derivative, Fair Value, Net	$ 0	$ 0

Commitments, Contingencies a107

Commitments, Contingencies and Derivatives (Summary of Contractual and Notional Amounts of Financial Instruments) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Home Equity Line of Credit [Member]
Financial Instruments [Line Items]
Contractual amounts of financial instrument	$ 477,401	$ 454,225
Commercial And Commercial Real Estate [Member]
Financial Instruments [Line Items]
Contractual amounts of financial instrument	49,482	83,103
Mortgage Loan Commitments [Member]
Financial Instruments [Line Items]
Contractual amounts of financial instrument	41,368	17,795
Letter of Credit [Member]
Financial Instruments [Line Items]
Contractual amounts of financial instrument	2,848	2,580
Other Commitments [Member]
Financial Instruments [Line Items]
Contractual amounts of financial instrument	523	432
Customer loan swaps
Financial Instruments [Line Items]
Notional amount of derivative	703,336	532,526
Forward-Starting Interest Rate Swap [Member]
Financial Instruments [Line Items]
Notional amount of derivative	50,000	50,000
Interest rate swaps
Financial Instruments [Line Items]
Notional amount of derivative	43,000	43,000
Interest Rate Lock Commitments [Member]
Financial Instruments [Line Items]
Notional amount of derivative	21,746	15,249
Forward Contracts [Member]
Financial Instruments [Line Items]
Notional amount of derivative	$ 8,065	$ 15,125

Commitments, Contingencies a108

Commitments, Contingencies and Derivatives (Commercial Loan Swaps) (Detail) - Interest Rate Swap [Member] swap in Thousands, $ in Thousands	Dec. 31, 2017USD ($)swap	Dec. 31, 2016USD ($)swap	Dec. 31, 2015USD ($)
Derivative Asset [Abstract]
Derivative, Fair Value, Net		$ (7,571)	$ (8,372)
Notional Amount	$ 43,000	$ 43,000
federal home loan bank 30-day [Member]
Derivative Liability [Abstract]
Derivative Liability, Number of Instruments Held | swap	42	50
Derivative Liability, Notional Amount	$ 226,884	$ 266,263
Derivative, Net Liability Position, Aggregate Fair Value	$ (5,036)	$ (1,945)
Derivative Asset [Abstract]
Derivative Asset, Number of Instruments Held | swap	23	0
Derivative Asset, Notional Amount	$ 124,784	$ 0
Derivative, Fair Value, Net	$ 1,799	$ 0
Commercial and Industrial Sector [Member]
Derivative Asset [Abstract]
Derivative Asset, Number of Instruments Held | swap	65	50
Derivative Asset, Notional Amount	$ 351,668	$ 266,263
Derivative, Fair Value, Net	3,237	1,945
Loans [Member]
Derivative Asset [Abstract]
Derivative, Fair Value, Net	$ 0	$ 0
Derivative, Number of Instruments Held | swap	130	100
Notional Amount	$ 703,336	$ 532,526

Commitments, Contingencies a109

Commitments, Contingencies and Derivatives (Swapped Variable Cost for Fixed Cost and Terms of Interest Rate Swap Agreements) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Forward-Starting Interest Rate Swap [Member]
Derivative [Line Items]
Notional Amount	$ 50,000	$ 50,000
Derivative, Fair Value, Net	21	(389)
Forward-Starting Interest Rate Swap [Member] | Contract, One
Derivative [Line Items]
Notional Amount	$ 25,000
Trade Date	Feb. 25, 2015
Maturity Date	Feb. 25, 2018
Fixed Rate Paid	1.54%
Derivative, Fair Value, Net	$ 20	(152)
Forward-Starting Interest Rate Swap [Member] | Contract, Two
Derivative [Line Items]
Notional Amount	$ 25,000
Trade Date	Feb. 25, 2015
Maturity Date	Feb. 25, 2019
Fixed Rate Paid	1.74%
Derivative, Fair Value, Net	$ 1	(237)
Interest rate swaps
Derivative [Line Items]
Notional Amount	$ 43,000	43,000
Derivative, Fair Value, Net		(7,571)	$ (8,372)
Interest rate swaps | Contract, One
Derivative [Line Items]
Notional Amount		$ 10,000
Trade Date		Mar. 18, 2009
Maturity Date		Jun. 30, 2021
Fixed Rate Paid		5.09%
Derivative, Fair Value, Net		$ (527)	(806)
Interest rate swaps | Contract, Two
Derivative [Line Items]
Notional Amount		$ 10,000
Trade Date		Jul. 8, 2009
Maturity Date		Jun. 30, 2029
Fixed Rate Paid		5.84%
Derivative, Fair Value, Net		$ (2,133)	(2,321)
Interest rate swaps | Contract, Three
Derivative [Line Items]
Notional Amount		$ 10,000
Trade Date		May 6, 2010
Maturity Date		Jun. 30, 2030
Fixed Rate Paid		5.71%
Derivative, Fair Value, Net		$ (2,129)	(2,290)
Interest rate swaps | Contract, Four
Derivative [Line Items]
Notional Amount		$ 5,000
Trade Date		Mar. 14, 2011
Maturity Date		Mar. 30, 2031
Fixed Rate Paid		4.35%
Derivative, Fair Value, Net		$ (1,137)	(1,211)
Interest rate swaps | Contract, Five
Derivative [Line Items]
Notional Amount		$ 8,000
Trade Date		May 4, 2011
Maturity Date		Jul. 7, 2031
Fixed Rate Paid		4.14%
Derivative, Fair Value, Net		$ (1,645)	$ (1,744)

Commitments, Contingencies a110

Commitments, Contingencies and Derivatives (Derivatives Effect on Earnings) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Effective portion of unrealized losses recognized within AOCI during the period, net of tax	$ (248)	$ (637)	$ (1,533)
Net reclassification adjustment for effective portion of cash flow hedges included in interest expense, gross(1)	$ 1,592	$ 2,026	$ 1,695

Commitments, Contingencies a111

Commitments, Contingencies and Derivatives (Interest rate locks) (Details) - Interest Rate Lock Commitments [Member] - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Other Commitments [Line Items]
Notional Amount	$ 21,746	$ 15,249
Derivative, Fair Value, Net	285	187
Derivative Liability, Fair Value, Gross Liability	(22)	(15)
Derivative Asset, Fair Value, Gross Asset	307	202
Other Liabilities [Member]
Other Commitments [Line Items]
Notional Amount	1,860	2,939
Other Assets [Member]
Other Commitments [Line Items]
Notional Amount	$ 19,886	$ 12,310

Commitments, Contingencies a112

Commitments, Contingencies and Derivatives (Forward Contracts) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Interest Rate Lock Commitments [Member]
Other Commitments [Line Items]
Notional Amount	$ 21,746	$ 15,249
Derivative Asset, Fair Value, Gross Asset	307	202
Derivative Liability, Fair Value, Gross Liability	(22)	(15)
Derivative, Fair Value, Net	285	187
Interest Rate Lock Commitments [Member] | Other Assets [Member]
Other Commitments [Line Items]
Notional Amount	19,886	12,310
Interest Rate Lock Commitments [Member] | Other Liabilities [Member]
Other Commitments [Line Items]
Notional Amount	1,860	2,939
Forward Contracts [Member]
Other Commitments [Line Items]
Notional Amount	8,065	15,125
Derivative Asset, Fair Value, Gross Asset	158	587
Derivative Liability, Fair Value, Gross Liability	(16)	(309)
Derivative, Fair Value, Net	142	278
Forward Contracts [Member] | Other Assets [Member]
Other Commitments [Line Items]
Notional Amount	6,692	14,250
Forward Contracts [Member] | Other Liabilities [Member]
Other Commitments [Line Items]
Notional Amount	$ 1,373	$ 875

Fair Value (Summary of Financia

Fair Value (Summary of Financial Assets and Liabilities Measured at Fair Value on Recurring Basis) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans Held-for-sale, Fair Value Disclosure	$ 8,103	$ 14,836
Loans Held-for-sale	8,103	14,836
Financial Assets:
AFS securities	789,899	779,867
Obligations of states and political subdivisions [Member]
Financial Assets:
AFS securities	7,335	9,001
Mortgage-backed securities issued or guaranteed by U.S. government sponsored enterprises [Member]
Financial Assets:
AFS securities	503,302	480,622
Collateralized mortgage obligations issued or guaranteed by U.S. government sponsored enterprises [Member]
Financial Assets:
AFS securities	272,799	283,890
Equity Securities [Member]
Financial Assets:
AFS securities	806	741
Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans Held-for-sale	8,103	14,836
Financial Liabilities:
Junior subordinated debt interest rate swaps	7,571	8,372
Fair Value, Measurements, Recurring [Member] | Obligations of states and political subdivisions [Member]
Financial Assets:
AFS securities	7,335
Fair Value, Measurements, Recurring [Member] | Mortgage-backed securities issued or guaranteed by U.S. government sponsored enterprises [Member]
Financial Assets:
AFS securities	503,302	9,001
Fair Value, Measurements, Recurring [Member] | Collateralized mortgage obligations issued or guaranteed by U.S. government sponsored enterprises [Member]
Financial Assets:
AFS securities	272,799	480,622
Fair Value, Measurements, Recurring [Member] | Corporate Bond Securities [Member]
Financial Assets:
AFS securities	5,657	283,890
Fair Value, Measurements, Recurring [Member] | Equity Securities [Member]
Financial Assets:
AFS securities	806	5,613
Readily Available Market Prices (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans Held-for-sale, Fair Value Disclosure	0	0
Financial Assets:
AFS securities	0	0
Readily Available Market Prices (Level 1) [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans Held-for-sale	0	0
Readily Available Market Prices (Level 1) [Member] | Fair Value, Measurements, Recurring [Member] | Corporate Bond Securities [Member]
Financial Assets:
AFS securities	0	0
Readily Available Market Prices (Level 1) [Member] | Fair Value, Measurements, Recurring [Member] | Equity Securities [Member]
Financial Assets:
AFS securities	0	0
Observable Market Data (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans Held-for-sale, Fair Value Disclosure	8,103	14,836
Financial Assets:
AFS securities	789,899	779,867
Observable Market Data (Level 2) [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans Held-for-sale	8,103	14,836
Financial Liabilities:
Junior subordinated debt interest rate swaps	7,571	8,372
Observable Market Data (Level 2) [Member] | Fair Value, Measurements, Recurring [Member] | Obligations of states and political subdivisions [Member]
Financial Assets:
AFS securities	7,335
Observable Market Data (Level 2) [Member] | Fair Value, Measurements, Recurring [Member] | Mortgage-backed securities issued or guaranteed by U.S. government sponsored enterprises [Member]
Financial Assets:
AFS securities	503,302	9,001
Observable Market Data (Level 2) [Member] | Fair Value, Measurements, Recurring [Member] | Collateralized mortgage obligations issued or guaranteed by U.S. government sponsored enterprises [Member]
Financial Assets:
AFS securities	272,799	480,622
Observable Market Data (Level 2) [Member] | Fair Value, Measurements, Recurring [Member] | Corporate Bond Securities [Member]
Financial Assets:
AFS securities	5,657	283,890
Observable Market Data (Level 2) [Member] | Fair Value, Measurements, Recurring [Member] | Equity Securities [Member]
Financial Assets:
AFS securities	806	5,613
Company Determined Fair Value (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans Held-for-sale, Fair Value Disclosure	0	0
Financial Assets:
AFS securities	0	0
Company Determined Fair Value (Level 3) [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans Held-for-sale	0	0
Company Determined Fair Value (Level 3) [Member] | Fair Value, Measurements, Recurring [Member] | Corporate Bond Securities [Member]
Financial Assets:
AFS securities	0	0
Company Determined Fair Value (Level 3) [Member] | Fair Value, Measurements, Recurring [Member] | Equity Securities [Member]
Financial Assets:
AFS securities	0	0
Interest Rate Swap [Member]
Financial Assets:
Customer interest rate swaps	5,036	1,945
Financial Liabilities:
Junior subordinated debt interest rate swaps	7,571	8,372
Customer interest rate swaps	5,036	1,945
Interest Rate Swap [Member] | Fair Value, Measurements, Recurring [Member]
Financial Assets:
Customer interest rate swaps	5,036	1,945
Financial Liabilities:
Customer interest rate swaps	5,036	1,945
Interest Rate Swap [Member] | Readily Available Market Prices (Level 1) [Member]
Financial Assets:
Customer interest rate swaps	0	0
Financial Liabilities:
Junior subordinated debt interest rate swaps	0	0
Customer interest rate swaps	0	0
Interest Rate Swap [Member] | Observable Market Data (Level 2) [Member]
Financial Assets:
Customer interest rate swaps	5,036	1,945
Financial Liabilities:
Junior subordinated debt interest rate swaps	7,571	8,372
Customer interest rate swaps	5,036	1,945
Interest Rate Swap [Member] | Observable Market Data (Level 2) [Member] | Fair Value, Measurements, Recurring [Member]
Financial Assets:
Customer interest rate swaps	5,036	1,945
Financial Liabilities:
Customer interest rate swaps	5,036	1,945
Interest Rate Swap [Member] | Company Determined Fair Value (Level 3) [Member]
Financial Assets:
Customer interest rate swaps	0	0
Financial Liabilities:
Junior subordinated debt interest rate swaps	0	0
Customer interest rate swaps	0	0
Interest Rate Lock Commitments [Member]
Financial Assets:
Customer interest rate swaps	307	202
Financial Liabilities:
Customer interest rate swaps	22	15
Interest Rate Lock Commitments [Member] | Fair Value, Measurements, Recurring [Member]
Financial Assets:
Customer interest rate swaps	307	202
Financial Liabilities:
Customer interest rate swaps	22	15
Interest Rate Lock Commitments [Member] | Readily Available Market Prices (Level 1) [Member]
Financial Assets:
Customer interest rate swaps	0	0
Financial Liabilities:
Customer interest rate swaps	0	0
Interest Rate Lock Commitments [Member] | Observable Market Data (Level 2) [Member]
Financial Assets:
Customer interest rate swaps	307	202
Financial Liabilities:
Customer interest rate swaps	22	15
Interest Rate Lock Commitments [Member] | Observable Market Data (Level 2) [Member] | Fair Value, Measurements, Recurring [Member]
Financial Assets:
Customer interest rate swaps	307	202
Financial Liabilities:
Customer interest rate swaps	22	15
Interest Rate Lock Commitments [Member] | Company Determined Fair Value (Level 3) [Member]
Financial Assets:
Customer interest rate swaps	0	0
Financial Liabilities:
Customer interest rate swaps	0	0
Interest Rate Lock Commitments [Member] | Company Determined Fair Value (Level 3) [Member] | Fair Value, Measurements, Recurring [Member]
Financial Liabilities:
Customer interest rate swaps	0	0
Forward Contracts [Member]
Financial Assets:
Customer interest rate swaps	158	587
Financial Liabilities:
Junior subordinated debt interest rate swaps	21
Customer interest rate swaps	16	309
Forward Contracts [Member] | Fair Value, Measurements, Recurring [Member]
Financial Assets:
Customer interest rate swaps	158	587
Financial Liabilities:
Customer interest rate swaps	16	309
Forward Contracts [Member] | Readily Available Market Prices (Level 1) [Member]
Financial Assets:
Customer interest rate swaps	0	0
Financial Liabilities:
Junior subordinated debt interest rate swaps	0
Customer interest rate swaps	0	0
Forward Contracts [Member] | Observable Market Data (Level 2) [Member]
Financial Assets:
Customer interest rate swaps	158	587
Financial Liabilities:
Junior subordinated debt interest rate swaps	21
Customer interest rate swaps	16	309
Forward Contracts [Member] | Observable Market Data (Level 2) [Member] | Fair Value, Measurements, Recurring [Member]
Financial Assets:
Customer interest rate swaps	158	587
Financial Liabilities:
Customer interest rate swaps	16	309
Forward Contracts [Member] | Company Determined Fair Value (Level 3) [Member]
Financial Assets:
Customer interest rate swaps	0	0
Financial Liabilities:
Junior subordinated debt interest rate swaps	0
Customer interest rate swaps	0	0
Forward-Starting Interest Rate Swap [Member]
Financial Liabilities:
Junior subordinated debt interest rate swaps		389
Forward-Starting Interest Rate Swap [Member] | Fair Value, Measurements, Recurring [Member]
Financial Liabilities:
Junior subordinated debt interest rate swaps	21	389
Forward-Starting Interest Rate Swap [Member] | Readily Available Market Prices (Level 1) [Member]
Financial Liabilities:
Junior subordinated debt interest rate swaps		0
Forward-Starting Interest Rate Swap [Member] | Observable Market Data (Level 2) [Member]
Financial Liabilities:
Junior subordinated debt interest rate swaps		389
Forward-Starting Interest Rate Swap [Member] | Observable Market Data (Level 2) [Member] | Fair Value, Measurements, Recurring [Member]
Financial Liabilities:
Junior subordinated debt interest rate swaps	$ 21	389
Forward-Starting Interest Rate Swap [Member] | Company Determined Fair Value (Level 3) [Member]
Financial Liabilities:
Junior subordinated debt interest rate swaps		0
Other Assets [Member] | Fair Value, Measurements, Recurring [Member]
Financial Assets:
Customer interest rate swaps		741
Other Assets [Member] | Observable Market Data (Level 2) [Member] | Fair Value, Measurements, Recurring [Member]
Financial Assets:
Customer interest rate swaps		$ 741

Fair Value (Summary of Assets M

Fair Value (Summary of Assets Measured at Fair Value on Non Recurring Basis) (Details) - USD ($)		Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financing Receivable, Individually Evaluated for Impairment		$ 13,590,000	$ 20,254,000	$ 15,235,000
non-financial assets measured at fair value on recurring basis		0
Impaired Loans Collateral Dependent [Member] | Fair Value, Measurements, Nonrecurring [Member]
Assets:
Assets, Fair Value Disclosure		3,696,000	500,000
Impaired Loans Collateral Dependent [Member] | Fair Value, Measurements, Nonrecurring [Member] | Company Determined Fair Value (Level 3) [Member]
Assets:
Assets, Fair Value Disclosure		3,696,000	500,000
Servicing Contracts [Member] | Fair Value, Measurements, Nonrecurring [Member]
Assets:
Assets, Fair Value Disclosure	[1]	0	1,090,000
Servicing Contracts [Member] | Fair Value, Measurements, Nonrecurring [Member] | Company Determined Fair Value (Level 3) [Member]
Assets:
Assets, Fair Value Disclosure	[1]		1,090,000
Other Real Estate Owned [Member] | Fair Value, Measurements, Nonrecurring [Member]
Assets:
Assets, Fair Value Disclosure		130,000	922,000
Other Real Estate Owned [Member] | Fair Value, Measurements, Nonrecurring [Member] | Company Determined Fair Value (Level 3) [Member]
Assets:
Assets, Fair Value Disclosure		130,000	922,000
Minimum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financing Receivable, Individually Evaluated for Impairment		500,000	250,000
Consumer loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financing Receivable, Individually Evaluated for Impairment			7,000	74,000
Commercial loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financing Receivable, Individually Evaluated for Impairment		$ 1,791,000	$ 2,028,000	$ 3,937,000
[1]	Represents mortgage serving assets deemed to be impaired and a valuation allowance was established to carry at fair value at December 31, 2017 and 2016.

Fair Value (Valuation Methodolo

Fair Value (Valuation Methodology and Unobservable Inputs for Level Three Assets Measured at Fair Value on Non Recurring Basis) (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2017	Dec. 31, 2016
Other real estate owned [Member] | Fair Value, Measurements, Nonrecurring [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value		$ 130	$ 922
Company Determined Fair Value (Level 3) [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Estimated selling cost			10.00%
Company Determined Fair Value (Level 3) [Member] | Maximum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Estimated selling cost			10.00%
Company Determined Fair Value (Level 3) [Member] | Weighted Average [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Estimated selling cost			10.00%
Company Determined Fair Value (Level 3) [Member] | Impaired Loans Partially Charged Off [Member] | Market Approach Valuation Technique [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value		$ 86	$ 166
Company Determined Fair Value (Level 3) [Member] | Impaired Loans Partially Charged Off [Member] | Market Approach Valuation Technique [Member] | Minimum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Estimated selling cost		0.00%	0.00%
Fair Value Inputs, Discount Rate		0.00%	0.00%
Company Determined Fair Value (Level 3) [Member] | Impaired Loans Partially Charged Off [Member] | Market Approach Valuation Technique [Member] | Maximum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Estimated selling cost		10.00%	10.00%
Fair Value Inputs, Discount Rate		50.00%	0.00%
Company Determined Fair Value (Level 3) [Member] | Impaired Loans Partially Charged Off [Member] | Market Approach Valuation Technique [Member] | Weighted Average [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Estimated selling cost		6.00%	5.00%
Fair Value Inputs, Discount Rate		18.00%	0.00%
Company Determined Fair Value (Level 3) [Member] | Impaired Loans Specifically Reserved [Member] | Market Approach Valuation Technique [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value	[1]	$ 3,610	$ 334
Company Determined Fair Value (Level 3) [Member] | Impaired Loans Specifically Reserved [Member] | Market Approach Valuation Technique [Member] | Minimum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Estimated selling cost		10.00%	10.00%
Fair Value Inputs, Discount Rate	[1]	0.00%	0.00%
Company Determined Fair Value (Level 3) [Member] | Impaired Loans Specifically Reserved [Member] | Market Approach Valuation Technique [Member] | Maximum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Estimated selling cost		10.00%	10.00%
Fair Value Inputs, Discount Rate	[1]	0.00%	50.00%
Company Determined Fair Value (Level 3) [Member] | Impaired Loans Specifically Reserved [Member] | Market Approach Valuation Technique [Member] | Weighted Average [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Estimated selling cost		10.00%	10.00%
Fair Value Inputs, Discount Rate	[1]	0.00%	13.00%
Company Determined Fair Value (Level 3) [Member] | Other real estate owned [Member] | Market Approach Valuation Technique [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value		$ 130	$ 922
Company Determined Fair Value (Level 3) [Member] | Other real estate owned [Member] | Market Approach Valuation Technique [Member] | Minimum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Estimated selling cost		10.00%
Fair Value Inputs, Discount Rate		20.00%	0.00%
Company Determined Fair Value (Level 3) [Member] | Other real estate owned [Member] | Market Approach Valuation Technique [Member] | Maximum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Estimated selling cost		10.00%
Fair Value Inputs, Discount Rate		20.00%	73.00%
Company Determined Fair Value (Level 3) [Member] | Other real estate owned [Member] | Market Approach Valuation Technique [Member] | Weighted Average [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Estimated selling cost		10.00%
Fair Value Inputs, Discount Rate		20.00%	7.00%
Company Determined Fair Value (Level 3) [Member] | Other real estate owned [Member] | Fair Value, Measurements, Nonrecurring [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value		$ 130	$ 922
[1]	{F|ahBzfndlYmZpbGluZ3MtaHJkcmoLEgZYTUxEb2MiXlhCUkxEb2NHZW5JbmZvOmNkMmExNzVlODBiODQ0MTlhZDU3YmUyZTM3YjUyODhmfFRleHRTZWxlY3Rpb246RTRFRThFRTM2ODc4NUE4RUEzQTQzNkEzQTlBNEY4QjcM}

Fair Value (Carrying Amounts an

Fair Value (Carrying Amounts and Estimated Fair Value for Financial Instrument Assets and Liabilities) (Details) - USD ($) $ in Thousands		Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Financial assets:
Cash and due from banks		$ 102,971	$ 87,707
AFS securities		789,899	779,867
HTM securities		94,073	94,609
Held-to-maturity Securities, Fair Value		94,913	94,596
Loans Held-for-sale, Fair Value Disclosure		8,103	14,836
Servicing Asset at Fair Value, Amount		1,766	1,701	$ 2,947	$ 1,447
Interest Receivable Fair Value Disclosure		9,595	8,654
Financial liabilities:
Deposits		2,995,269	2,826,484
Federal Home Loan Bank Borrowings, Fair Value Disclosure		541,683	530,435
Securities Loaned or Sold under Agreements to Repurchase, Fair Value Disclosure		10,699	10,836
Subordinated debentures		44,333	41,660
Interest payable		564	534
Readily Available Market Prices (Level 1) [Member]
Financial assets:
Cash and due from banks		102,971	87,707
AFS securities		0	0
Held-to-maturity Securities, Fair Value		0	0
Loans Held-for-sale, Fair Value Disclosure		0	0
Servicing Asset at Fair Value, Amount		0	0
Interest Receivable Fair Value Disclosure		0	0
Financial liabilities:
Deposits		0	0
Federal Home Loan Bank Borrowings, Fair Value Disclosure		0	0
Securities Loaned or Sold under Agreements to Repurchase, Fair Value Disclosure		0	0
Subordinated debentures		0	0
Interest payable		0	0
Observable Market Data (Level 2) [Member]
Financial assets:
Cash and due from banks		0	0
AFS securities		789,899	779,867
Held-to-maturity Securities, Fair Value		94,913	94,596
Loans Held-for-sale, Fair Value Disclosure		8,103	14,836
Servicing Asset at Fair Value, Amount		1,766	1,701
Interest Receivable Fair Value Disclosure		9,595	8,654
Financial liabilities:
Deposits		2,995,269	2,826,484
Federal Home Loan Bank Borrowings, Fair Value Disclosure		541,683	530,435
Securities Loaned or Sold under Agreements to Repurchase, Fair Value Disclosure		10,699	10,836
Subordinated debentures		44,333	41,660
Interest payable		564	534
Company Determined Fair Value (Level 3) [Member]
Financial assets:
Cash and due from banks		0	0
AFS securities		0	0
Held-to-maturity Securities, Fair Value		0	0
Loans Held-for-sale, Fair Value Disclosure		0	0
Servicing Asset at Fair Value, Amount		0	0
Interest Receivable Fair Value Disclosure		0	0
Financial liabilities:
Deposits		0	0
Federal Home Loan Bank Borrowings, Fair Value Disclosure		0	0
Securities Loaned or Sold under Agreements to Repurchase, Fair Value Disclosure		0	0
Subordinated debentures		0	0
Interest payable		0	0
Carrying Amount [Member]
Financial assets:
Cash and due from banks		102,971	87,707
AFS securities		789,899	779,867
HTM securities		94,073	94,609
Loans Held-for-sale, Fair Value Disclosure		8,103	14,836
Servicing Asset at Fair Value, Amount		1,025	1,210
Interest Receivable Fair Value Disclosure		9,595	8,654
Financial liabilities:
Deposits		3,000,491	2,828,529
Federal Home Loan Bank Borrowings, Fair Value Disclosure		541,867	530,129
Securities Loaned or Sold under Agreements to Repurchase, Fair Value Disclosure		10,720	10,791
Subordinated debentures		58,911	58,755
Interest payable		564	534
Residential real estate loans
Financial assets:
Loans receivable, net of allowance	[1]	853,056	800,122
Residential real estate loans | Readily Available Market Prices (Level 1) [Member]
Financial assets:
Loans receivable, net of allowance	[1]	0	0
Residential real estate loans | Observable Market Data (Level 2) [Member]
Financial assets:
Loans receivable, net of allowance	[1]	0	0
Residential real estate loans | Company Determined Fair Value (Level 3) [Member]
Financial assets:
Loans receivable, net of allowance	[1]	853,056	800,122
Residential real estate loans | Carrying Amount [Member]
Financial assets:
Loans receivable, net of allowance	[1]	853,283	798,334
Commercial real estate loans
Financial assets:
Loans receivable, net of allowance	[1]	1,115,618	1,006,249
Commercial real estate loans | Readily Available Market Prices (Level 1) [Member]
Financial assets:
Loans receivable, net of allowance	[1]	0	0
Commercial real estate loans | Observable Market Data (Level 2) [Member]
Financial assets:
Loans receivable, net of allowance	[1]	0	0
Commercial real estate loans | Company Determined Fair Value (Level 3) [Member]
Financial assets:
Loans receivable, net of allowance	[1]	1,115,618	1,006,249
Commercial real estate loans | Carrying Amount [Member]
Financial assets:
Loans receivable, net of allowance	[1]	1,152,160	1,038,626
Commercial loans
Financial assets:
Loans receivable, net of allowance	[1],[2]	401,902	391,493
Commercial loans | Readily Available Market Prices (Level 1) [Member]
Financial assets:
Loans receivable, net of allowance	[1],[2]	0	0
Commercial loans | Observable Market Data (Level 2) [Member]
Financial assets:
Loans receivable, net of allowance	[1],[2]	0	0
Commercial loans | Company Determined Fair Value (Level 3) [Member]
Financial assets:
Loans receivable, net of allowance	[1],[2]	401,902	391,493
Commercial loans | Carrying Amount [Member]
Financial assets:
Loans receivable, net of allowance	[1],[2]	413,898	389,624
Home equity loans
Financial assets:
Loans receivable, net of allowance	[1]	318,230	327,292
Home equity loans | Readily Available Market Prices (Level 1) [Member]
Financial assets:
Loans receivable, net of allowance	[1]	0	0
Home equity loans | Observable Market Data (Level 2) [Member]
Financial assets:
Loans receivable, net of allowance	[1]	0	0
Home equity loans | Company Determined Fair Value (Level 3) [Member]
Financial assets:
Loans receivable, net of allowance	[1]	318,230	327,292
Home equity loans | Carrying Amount [Member]
Financial assets:
Loans receivable, net of allowance	[1]	321,011	327,713
Consumer loans
Financial assets:
Loans receivable, net of allowance	[1]	17,335	16,845
Consumer loans | Readily Available Market Prices (Level 1) [Member]
Financial assets:
Loans receivable, net of allowance	[1]	0	0
Consumer loans | Observable Market Data (Level 2) [Member]
Financial assets:
Loans receivable, net of allowance	[1]	0	0
Consumer loans | Company Determined Fair Value (Level 3) [Member]
Financial assets:
Loans receivable, net of allowance	[1]	17,335	16,845
Consumer loans | Carrying Amount [Member]
Financial assets:
Loans receivable, net of allowance	[1]	17,916	17,151
Fair Value, Measurements, Recurring [Member]
Financial liabilities:
Junior subordinated debt interest rate swaps		7,571	8,372
Fair Value, Measurements, Recurring [Member] | Observable Market Data (Level 2) [Member]
Financial liabilities:
Junior subordinated debt interest rate swaps		7,571	8,372
Forward-Starting Interest Rate Swap [Member]
Financial liabilities:
Junior subordinated debt interest rate swaps			389
Forward-Starting Interest Rate Swap [Member] | Readily Available Market Prices (Level 1) [Member]
Financial liabilities:
Junior subordinated debt interest rate swaps			0
Forward-Starting Interest Rate Swap [Member] | Observable Market Data (Level 2) [Member]
Financial liabilities:
Junior subordinated debt interest rate swaps			389
Forward-Starting Interest Rate Swap [Member] | Company Determined Fair Value (Level 3) [Member]
Financial liabilities:
Junior subordinated debt interest rate swaps			0
Forward-Starting Interest Rate Swap [Member] | Carrying Amount [Member]
Financial liabilities:
Junior subordinated debt interest rate swaps			389
Forward-Starting Interest Rate Swap [Member] | Fair Value, Measurements, Recurring [Member]
Financial liabilities:
Junior subordinated debt interest rate swaps		21	389
Forward-Starting Interest Rate Swap [Member] | Fair Value, Measurements, Recurring [Member] | Observable Market Data (Level 2) [Member]
Financial liabilities:
Junior subordinated debt interest rate swaps		21	389
Interest Rate Swap [Member]
Financial assets:
Interest Rate Derivative Instruments Not Designated as Hedging Instruments, Asset at Fair Value		5,036	1,945
Financial liabilities:
Junior subordinated debt interest rate swaps		7,571	8,372
Interest Rate Derivative Instruments Not Designated as Hedging Instruments, Liability at Fair Value		5,036	1,945
Interest Rate Swap [Member] | Readily Available Market Prices (Level 1) [Member]
Financial assets:
Interest Rate Derivative Instruments Not Designated as Hedging Instruments, Asset at Fair Value		0	0
Financial liabilities:
Junior subordinated debt interest rate swaps		0	0
Interest Rate Derivative Instruments Not Designated as Hedging Instruments, Liability at Fair Value		0	0
Interest Rate Swap [Member] | Observable Market Data (Level 2) [Member]
Financial assets:
Interest Rate Derivative Instruments Not Designated as Hedging Instruments, Asset at Fair Value		5,036	1,945
Financial liabilities:
Junior subordinated debt interest rate swaps		7,571	8,372
Interest Rate Derivative Instruments Not Designated as Hedging Instruments, Liability at Fair Value		5,036	1,945
Interest Rate Swap [Member] | Company Determined Fair Value (Level 3) [Member]
Financial assets:
Interest Rate Derivative Instruments Not Designated as Hedging Instruments, Asset at Fair Value		0	0
Financial liabilities:
Junior subordinated debt interest rate swaps		0	0
Interest Rate Derivative Instruments Not Designated as Hedging Instruments, Liability at Fair Value		0	0
Interest Rate Swap [Member] | Carrying Amount [Member]
Financial assets:
Interest Rate Derivative Instruments Not Designated as Hedging Instruments, Asset at Fair Value		5,036	1,945
Financial liabilities:
Junior subordinated debt interest rate swaps		7,571	8,372
Interest Rate Derivative Instruments Not Designated as Hedging Instruments, Liability at Fair Value		5,036	1,945
Interest Rate Swap [Member] | Fair Value, Measurements, Recurring [Member]
Financial assets:
Interest Rate Derivative Instruments Not Designated as Hedging Instruments, Asset at Fair Value		5,036	1,945
Financial liabilities:
Interest Rate Derivative Instruments Not Designated as Hedging Instruments, Liability at Fair Value		5,036	1,945
Interest Rate Swap [Member] | Fair Value, Measurements, Recurring [Member] | Observable Market Data (Level 2) [Member]
Financial assets:
Interest Rate Derivative Instruments Not Designated as Hedging Instruments, Asset at Fair Value		5,036	1,945
Financial liabilities:
Interest Rate Derivative Instruments Not Designated as Hedging Instruments, Liability at Fair Value		5,036	1,945
Interest Rate Lock Commitments [Member]
Financial assets:
Interest Rate Derivative Instruments Not Designated as Hedging Instruments, Asset at Fair Value		307	202
Financial liabilities:
Interest Rate Derivative Instruments Not Designated as Hedging Instruments, Liability at Fair Value		22	15
Interest Rate Lock Commitments [Member] | Readily Available Market Prices (Level 1) [Member]
Financial assets:
Interest Rate Derivative Instruments Not Designated as Hedging Instruments, Asset at Fair Value		0	0
Financial liabilities:
Interest Rate Derivative Instruments Not Designated as Hedging Instruments, Liability at Fair Value		0	0
Interest Rate Lock Commitments [Member] | Observable Market Data (Level 2) [Member]
Financial assets:
Interest Rate Derivative Instruments Not Designated as Hedging Instruments, Asset at Fair Value		307	202
Financial liabilities:
Interest Rate Derivative Instruments Not Designated as Hedging Instruments, Liability at Fair Value		22	15
Interest Rate Lock Commitments [Member] | Company Determined Fair Value (Level 3) [Member]
Financial assets:
Interest Rate Derivative Instruments Not Designated as Hedging Instruments, Asset at Fair Value		0	0
Financial liabilities:
Interest Rate Derivative Instruments Not Designated as Hedging Instruments, Liability at Fair Value		0	0
Interest Rate Lock Commitments [Member] | Carrying Amount [Member]
Financial assets:
Interest Rate Derivative Instruments Not Designated as Hedging Instruments, Asset at Fair Value		307	202
Financial liabilities:
Interest Rate Derivative Instruments Not Designated as Hedging Instruments, Liability at Fair Value		22	15
Interest Rate Lock Commitments [Member] | Fair Value, Measurements, Recurring [Member]
Financial assets:
Interest Rate Derivative Instruments Not Designated as Hedging Instruments, Asset at Fair Value		307	202
Financial liabilities:
Interest Rate Derivative Instruments Not Designated as Hedging Instruments, Liability at Fair Value		22	15
Interest Rate Lock Commitments [Member] | Fair Value, Measurements, Recurring [Member] | Observable Market Data (Level 2) [Member]
Financial assets:
Interest Rate Derivative Instruments Not Designated as Hedging Instruments, Asset at Fair Value		307	202
Financial liabilities:
Interest Rate Derivative Instruments Not Designated as Hedging Instruments, Liability at Fair Value		22	15
Interest Rate Lock Commitments [Member] | Fair Value, Measurements, Recurring [Member] | Company Determined Fair Value (Level 3) [Member]
Financial liabilities:
Interest Rate Derivative Instruments Not Designated as Hedging Instruments, Liability at Fair Value		0	0
Forward Contracts [Member]
Financial assets:
Interest Rate Derivative Instruments Not Designated as Hedging Instruments, Asset at Fair Value		158	587
Financial liabilities:
Junior subordinated debt interest rate swaps		21
Interest Rate Derivative Instruments Not Designated as Hedging Instruments, Liability at Fair Value		16	309
Forward Contracts [Member] | Readily Available Market Prices (Level 1) [Member]
Financial assets:
Interest Rate Derivative Instruments Not Designated as Hedging Instruments, Asset at Fair Value		0	0
Financial liabilities:
Junior subordinated debt interest rate swaps		0
Interest Rate Derivative Instruments Not Designated as Hedging Instruments, Liability at Fair Value		0	0
Forward Contracts [Member] | Observable Market Data (Level 2) [Member]
Financial assets:
Interest Rate Derivative Instruments Not Designated as Hedging Instruments, Asset at Fair Value		158	587
Financial liabilities:
Junior subordinated debt interest rate swaps		21
Interest Rate Derivative Instruments Not Designated as Hedging Instruments, Liability at Fair Value		16	309
Forward Contracts [Member] | Company Determined Fair Value (Level 3) [Member]
Financial assets:
Interest Rate Derivative Instruments Not Designated as Hedging Instruments, Asset at Fair Value		0	0
Financial liabilities:
Junior subordinated debt interest rate swaps		0
Interest Rate Derivative Instruments Not Designated as Hedging Instruments, Liability at Fair Value		0	0
Forward Contracts [Member] | Carrying Amount [Member]
Financial assets:
Interest Rate Derivative Instruments Not Designated as Hedging Instruments, Asset at Fair Value		158	587
Financial liabilities:
Junior subordinated debt interest rate swaps		21
Interest Rate Derivative Instruments Not Designated as Hedging Instruments, Liability at Fair Value		16	309
Forward Contracts [Member] | Fair Value, Measurements, Recurring [Member]
Financial assets:
Interest Rate Derivative Instruments Not Designated as Hedging Instruments, Asset at Fair Value		158	587
Financial liabilities:
Interest Rate Derivative Instruments Not Designated as Hedging Instruments, Liability at Fair Value		16	309
Forward Contracts [Member] | Fair Value, Measurements, Recurring [Member] | Observable Market Data (Level 2) [Member]
Financial assets:
Interest Rate Derivative Instruments Not Designated as Hedging Instruments, Asset at Fair Value		158	587
Financial liabilities:
Interest Rate Derivative Instruments Not Designated as Hedging Instruments, Liability at Fair Value		$ 16	$ 309
[1]	(1)The presented carrying amount is net of the allocated ALL.
[2]	(2)Includes the HPFC loan portfolio.

Parent Company Financial Sta117

Parent Company Financial Statements (Statements of Condition) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Investment in subsidiaries:
Other assets	$ 36,606	$ 30,844
Total assets	4,065,398	3,864,230
LIABILITIES AND SHAREHOLDERS' EQUITY
Accrued interest and other liabilities	49,996	44,479
Shareholders’ equity	403,413	391,547	$ 363,190	$ 245,109
Total liabilities and shareholders’ equity	4,065,398	3,864,230
Parent Company [Member]
ASSETS
Cash	29,365	29,905
Investment in subsidiaries:
Investment in subsidiary	444,235	429,100
Receivable from subsidiary	107	107
Other assets	14,806	12,420
Total assets	488,513	471,532
LIABILITIES AND SHAREHOLDERS' EQUITY
Subordinated debentures	58,911	58,755
Due to subsidiary	17	37
Accrued interest and other liabilities	26,172	21,193
Shareholders’ equity	403,413	391,547
Total liabilities and shareholders’ equity	$ 488,513	$ 471,532

Parent Company Financial Sta118

Parent Company Financial Statements (Statements of Income) (Details) - USD ($)	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Condensed Financial Statements, Captions [Line Items]
Dividend income from subsidiary									$ 1,100,000	$ 1,000,000	$ 579,000
Interest on borrowings									5,585,000	4,506,000	3,457,000
Income before income tax expense	$ 16,162,000	$ 16,817,000	$ 14,955,000	$ 14,420,000	$ 15,632,000	$ 15,945,000	$ 13,874,000	$ 12,088,000	62,354,000	57,539,000	30,859,000
Income tax (expense) benefit	(19,335,000)	(5,478,000)	(4,721,000)	(4,344,000)	(4,730,000)	(5,042,000)	(4,258,000)	(3,442,000)	(33,878,000)	(17,472,000)	(9,907,000)
Net income	$ (3,173,000)	$ 11,339,000	$ 10,234,000	$ 10,076,000	$ 10,902,000	$ 10,903,000	$ 9,616,000	$ 8,646,000	28,476,000	40,067,000	20,952,000
Parent Company [Member]
Condensed Financial Statements, Captions [Line Items]
Dividend income from subsidiary									16,800,000	16,000,000	39,200,000
Other income (loss)									145,000	239,000	(18,000)
Total operating income									16,945,000	16,239,000	39,182,000
Interest on borrowings									3,408,000	3,415,000	2,734,000
Fees to Bank									160,000	160,000	160,000
Other operating expenses									592,000	748,000	469,000
Total operating expenses									4,160,000	4,323,000	3,363,000
Income before equity in undistributed earnings of subsidiaries and income taxes									12,785,000	11,916,000	35,819,000
Equity in undistributed income (losses) of subsidiaries									17,405,000	26,773,000	(15,999,000)
Income before income tax expense									30,190,000	38,689,000	19,820,000
Income tax (expense) benefit									(1,714,000)	1,378,000	1,132,000
Net income									$ 28,476,000	$ 40,067,000	$ 20,952,000

Parent Company Financial Sta119

Parent Company Financial Statements (Statements of Cash Flows) (Details) - USD ($)	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Operating Activities
Net income	$ (3,173,000)	$ 11,339,000	$ 10,234,000	$ 10,076,000	$ 10,902,000	$ 10,903,000	$ 9,616,000	$ 8,646,000	$ 28,476,000	$ 40,067,000	$ 20,952,000
(Increase) decrease in other assets									12,060,000	11,836,000	(7,062,000)
Net cash provided by operating activities									58,334,000	58,510,000	15,918,000
Investing Activities
Net cash used in investing activities									(212,131,000)	(169,045,000)	(54,744,000)
Financing Activities
Issuance of subordinated debt, net of issuance costs									0	0	14,464,000
Exercise of stock options and issuance of restricted stock, net of repurchase for tax withholdings									606,000	(894,000)	(753,000)
Equity issuance costs									0	0	(612,000)
Cash dividends paid on common stock and cash in lieu for fractional shares paid due to stock split									(14,323,000)	(12,394,000)	(9,785,000)
Net cash provided by financing activities									169,061,000	118,754,000	57,501,000
Net increase in cash and cash equivalents									15,264,000	8,219,000	18,675,000
Cash and cash equivalents at beginning of year				87,707,000				79,488,000	87,707,000	79,488,000	60,813,000
Cash and cash equivalents at end of year	102,971,000				87,707,000				102,971,000	87,707,000	79,488,000
Parent Company [Member]
Operating Activities
Net income									28,476,000	40,067,000	20,952,000
Equity in undistributed (income) losses of subsidiaries									(17,405,000)	(26,655,000)	4,573,000
Gain on sale of investment securities									(32,000)	(4,000)	0
(Increase) decrease in receivable from subsidiaries									0	1,819,000	(1,901,000)
(Increase) decrease in other assets									(1,930,000)	1,213,000	(2,175,000)
Increase (decrease) in due to subsidiaries									(20,000)	(1,179,000)	1,216,000
Increase (decrease) in other liabilities									3,721,000	(2,519,000)	320,000
Net cash provided by operating activities									12,810,000	12,742,000	22,985,000
Investing Activities
Acquisition of SBM, net of cash acquired									0	0	(25,319,000)
Proceeds from Sale of Available-for-sale Securities, Equity									110,000	84,000	0
Net cash used in investing activities									110,000	84,000	(25,319,000)
Financing Activities
Issuance of subordinated debt, net of issuance costs									0	0	14,464,000
Exercise of stock options and issuance of restricted stock, net of repurchase for tax withholdings									606,000	(894,000)	(753,000)
Capital contribution from subsidiaries									1,469,000	1,997,000	836,000
Equity issuance costs									0	0	(612,000)
Cash dividends paid on common stock and cash in lieu for fractional shares paid due to stock split									(14,323,000)	(12,393,000)	(9,785,000)
Net cash provided by financing activities									(13,460,000)	(9,502,000)	5,656,000
Net increase in cash and cash equivalents									(540,000)	3,324,000	3,322,000
Cash and cash equivalents at beginning of year				$ 29,905,000				$ 26,581,000	29,905,000	26,581,000	23,259,000
Cash and cash equivalents at end of year	$ 29,365,000				$ 29,905,000				$ 29,365,000	$ 29,905,000	$ 26,581,000

Quarterly Results of Operati120

Quarterly Results of Operations (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Quarterly Financial Information Disclosure [Abstract]
Interest income	$ 35,040	$ 34,710	$ 33,940	$ 32,414	$ 32,276	$ 32,594	$ 32,775	$ 31,981	$ 136,104	$ 129,626	$ 99,144
Interest expense	5,381	5,550	5,314	4,559	4,032	4,222	4,271	4,029	20,804	16,554	12,692
Net interest income	29,659	29,160	28,626	27,855	28,244	28,372	28,504	27,952	115,300	113,072	86,452
Provision for credit losses	238	817	1,401	579	255	1,279	2,852	872	3,035	5,258	1,936
Non-interest income	9,840	10,299	9,888	8,572	10,151	11,001	10,552	7,917	38,599	39,621	27,482
Non-interest expense	23,099	21,825	22,158	21,428	22,508	22,149	22,330	22,909	88,510	89,896	81,139
Income before income tax expense	16,162	16,817	14,955	14,420	15,632	15,945	13,874	12,088	62,354	57,539	30,859
Income tax expense	19,335	5,478	4,721	4,344	4,730	5,042	4,258	3,442	33,878	17,472	9,907
Net income	$ (3,173)	$ 11,339	$ 10,234	$ 10,076	$ 10,902	$ 10,903	$ 9,616	$ 8,646	$ 28,476	$ 40,067	$ 20,952
Per common share:
Basic earnings per share	$ (0.20)	$ 0.72	$ 0.66	$ 0.65	$ 0.70	$ 0.70	$ 0.62	$ 0.56	$ 1.83	$ 2.59	$ 1.73
Diluted earnings per share	(0.20)	$ 0.72	$ 0.66	$ 0.64	$ 0.70	$ 0.70	$ 0.62	$ 0.56	$ 1.82	$ 2.57	$ 1.73
Change in federal corporate income tax rate									$ 14,263	$ 0	$ 0
Impact of Restatement on Earnings Per Share, Diluted	$ 0.91