Berkshire Hills Bancorp (BHLB) 10-K 1 Mar 18 2017 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($) $ in Billions	12 Months Ended
	Dec. 31, 2017	Feb. 23, 2018	Jun. 30, 2017
Document and Entity Information
Entity Registrant Name	BERKSHIRE HILLS BANCORP INC
Entity Central Index Key	1,108,134
Document Type	10-K
Document Period End Date	Dec. 31, 2017
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Public Float			$ 1.4
Entity Common Stock, Shares Outstanding (shares)		45,369,422
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	FY

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Assets
Cash and due from banks	$ 91,122	$ 71,494
Short-term investments	157,641	41,581
Total cash and cash equivalents	248,763	113,075
Trading security	12,277	13,229
Securities available for sale, at fair value	1,426,099	1,209,537
Securities held to maturity (fair values of 405,276 in 2017 and $337,680 in 2016)	397,103	334,368
Federal Home Loan Bank stock and other restricted securities	63,085	71,112
Total securities	1,898,564	1,628,246
Loans held for sale, at fair value	153,620	120,673
Commercial real estate	3,264,742	2,616,438
Commercial and industrial loans	1,803,939	1,062,038
Residential mortgages	2,102,807	1,893,131
Consumer loans	1,127,850	978,180
Total loans	8,299,338	6,549,787
Less: Allowance for loan losses	(51,834)	(43,998)
Net loans	8,247,504	6,505,789
Premises and equipment, net	109,352	93,215
Other real estate owned	0	151
Goodwill	519,287	403,106
Other intangible assets	38,296	19,445
Cash surrender value of bank-owned life insurance	191,221	139,257
Deferred tax assets, net	47,061	41,128
Other assets	117,083	98,457
Total assets	11,570,751	9,162,542
Liabilities
Demand deposits	1,667,323	1,278,875
NOW deposits	673,891	570,583
Money market deposits	2,776,157	1,781,605
Savings deposits	741,954	657,486
Time deposits	2,890,205	2,333,543
Total deposits	8,749,530	6,622,092
Short-term debt	667,300	1,082,044
Long-term Federal Home Loan Bank advances	380,436	142,792
Subordinated notes	89,339	89,161
Total borrowings	1,137,075	1,313,997
Other liabilities	187,882	133,155
Total liabilities	10,074,487	8,069,244
Shareholders’ equity
Preferred Stock (Series B non-voting convertible preferred stock - $0.01 par value; 1,000,000 shares authorized, 521,607 shares issued and outstanding in 2017; 1,000,000 shares authorized, no shares issued and outstanding in 2016)	40,633	0
Common stock ($.01 par value; 50,000,000 shares authorized, 46,211,894 shares issued, and 45,290,433 shares outstanding in 2017; 50,000,000 shares authorized, 36,732,129 shares issued, and 35,672,817 shares outstanding in 2016)	460	366
Additional paid-in capital - common stock	1,242,487	898,989
Unearned compensation	(6,531)	(6,374)
Retained earnings	239,179	217,494
Accumulated other comprehensive income (loss)	4,161	9,766
Treasury stock, at cost (921,461 shares in 2017 and 1,059,312 shares in 2016)	(24,125)	(26,943)
Total shareholders’ equity	1,496,264	1,093,298
Total liabilities and shareholders’ equity	$ 11,570,751	$ 9,162,542

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Held-to-maturity securities, fair value	$ 405,276	$ 337,680
Common stock, par value (USD per share)	$ 0.01	$ 0.01
Common stock, shares authorized (shares)	50,000,000	50,000,000
Common stock, shares issued (shares)	46,211,894	36,732,129
Common stock, shares outstanding (shares)	45,290,433	35,672,817
Treasury stock, shares (shares)	921,461	1,059,312
Series B Convertible Preferred Stock
Preferred stock, par value (USD per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized (shares)	1,000,000	1,000,000
Preferred stock, shares issued (shares)	521,607	0
Preferred stock, shares outstanding (shares)	521,607	0

CONSOLIDATED STATEMENTS OF INCO

CONSOLIDATED STATEMENTS OF INCOME - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Interest and dividend income
Loans	$ 308,099	$ 242,600	$ 211,347
Securities and other	52,159	37,839	35,683
Total interest and dividend income	360,258	280,439	247,030
Interest expense
Deposits	43,855	30,883	22,948
Borrowings and subordinated notes	21,608	17,289	10,233
Total interest expense	65,463	48,172	33,181
Net interest income	294,795	232,267	213,849
Non-interest income
Mortgage banking income	54,251	7,555	4,133
Loan related income	21,401	16,694	8,310
Deposit related fees	27,165	24,963	25,084
Insurance commissions and fees	10,589	10,477	10,251
Wealth management fees	9,395	8,917	9,702
Total fee income	122,801	68,606	57,480
Other	(3,377)	(3,289)	(5,302)
Gain (Loss) on securities, net	12,598	(551)	2,110
Gain on sale of business operations, net	296	1,085	0
Loss on termination of hedges	(6,629)	0	0
Total non-interest income	125,689	65,851	54,288
Total net revenue	420,484	298,118	268,137
Provision for loan losses	21,025	17,362	16,726
Non-interest expense
Compensation and benefits	152,979	104,600	97,370
Occupancy and equipment	35,422	27,220	28,486
Technology and communications	25,900	19,883	16,881
Marketing and promotion	11,877	3,161	3,306
Professional services	9,165	6,199	5,172
FDIC premiums and assessments	6,457	5,066	4,649
Other real estate owned and foreclosures	44	691	833
Amortization of intangible assets	3,493	2,927	3,563
Merger, restructuring and conversion related expenses	31,558	15,461	17,611
Other	22,815	18,094	18,958
Total non-interest expense	299,710	203,302	196,829
Income from continuing operations before income taxes	99,749	77,454	54,582
Income tax expense	44,502	18,784	5,064
Net income	55,247	58,670	49,518
Preferred stock dividend	219	0	0
Income available to common shareholders	$ 55,028	$ 58,670	$ 49,518
Earnings per common share:
Basic earnings per share (USD per share)	$ 1.40	$ 1.89	$ 1.74
Diluted earnings per share (USD per share)	$ 1.39	$ 1.88	$ 1.73
Weighted average common shares outstanding:
Basic (shares)	39,456	30,988	28,393
Diluted (shares)	39,695	31,167	28,564

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	$ 55,247	$ 58,670	$ 49,518
Other comprehensive income (loss), before tax:
Changes in unrealized gains and losses on securities available-for-sale	(15,142)	18,859	(9,677)
Changes in unrealized gains and losses on derivative hedges	6,573	1,959	(5,232)
Changes in unrealized gains and losses on pension	(94)	515	(1,177)
Total other comprehensive income (loss), before tax	(8,663)	21,333	(16,086)
Income taxes related to other comprehensive income (loss):
Changes in unrealized gains and losses on securities available-for-sale	5,610	(7,199)	3,640
Changes in unrealized gains and losses on derivative hedges	(2,589)	(835)	2,094
Changes in unrealized gains and losses on pension	37	(228)	468
Total income tax (expense) benefit related to other comprehensive income (loss)	3,058	(8,262)	6,202
Total other comprehensive income (loss)	(5,605)	13,071	(9,884)
Total comprehensive income	$ 49,642	$ 71,741	$ 39,634

CONSOLIDATED STATEMENTS OF CHAN

CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY - USD ($) $ in Thousands		Total	Hampden Bancorp Inc	Firestone Financial	44 Business Capital	First Choice Bank	Commerce Bank	Preferred Stock	Preferred StockCommerce Bank	Common Stock	Common StockHampden Bancorp Inc	Common StockFirestone Financial	Common Stock44 Business Capital	Common StockFirst Choice Bank	Common StockCommerce Bank	Additional paid-in capital	Additional paid-in capitalHampden Bancorp Inc	Additional paid-in capitalFirestone Financial	Additional paid-in capitalFirst Choice Bank	Additional paid-in capitalCommerce Bank	Unearned compensation	Retained earnings	Accumulated other comprehensive (loss) income	Treasury stock	Treasury stock44 Business Capital
Beginning balance (shares) at Dec. 31, 2014								0		25,183,000
Beginning balance at Dec. 31, 2014		$ 709,287						$ 0		$ 265						$ 585,289					$ (6,147)	$ 156,446	$ 6,579	$ (33,145)
Comprehensive income:
Net income		49,518																				49,518
Other net comprehensive income (loss)		(9,884)																					(9,884)
Total comprehensive income		39,634																				49,518	(9,884)
Stock issued pursuant to acquisition (shares)											4,186,000	1,442,000
Stock issued pursuant to acquisition			$ 114,604	$ 42,107							$ 42	$ 15					$ 114,562	$ 42,092
Cash dividends declared on common shares		(21,903)																				(21,903)
Treasury stock purchased (shares)										(18,000)
Treasury stock purchased		(550)																						(550)
Forfeited shares (shares)										(20,000)
Forfeited shares		0														47					509			(556)
Exercise of stock options (shares)										16,000
Exercise of stock options		239																				(176)		415
Restricted stock grants (shares)										226,000
Restricted stock grants		0														440					(6,029)			5,589
Stock-based compensation		4,670																			4,670
Net tax benefit related to stock-based compensation		167														167
Other, net (shares)										(41,000)
Other, net		(1,066)														22								(1,088)
Ending balance (shares) at Dec. 31, 2015								0		30,974,000
Ending balance at Dec. 31, 2015		887,189						$ 0		$ 322						742,619					(6,997)	183,885	(3,305)	(29,335)
Comprehensive income:
Net income		58,670																				58,670
Other net comprehensive income (loss)		13,071																					13,071
Total comprehensive income		71,741																				58,670	13,071
Stock issued pursuant to acquisition (shares)													45,000	4,410,000
Stock issued pursuant to acquisition					$ 1,217	$ 151,048								$ 44					$ 151,004						$ 1,217
Cash dividends declared on common shares		(24,916)																				(24,916)
Treasury stock adjustment	[1]	0														4,632								(4,632)
Forfeited shares (shares)										(70,000)
Forfeited shares		0														148					1,789			(1,937)
Exercise of stock options (shares)										151,000
Exercise of stock options		3,712																				(145)		3,857
Restricted stock grants (shares)										211,000
Restricted stock grants		0														575					(5,787)			5,212
Stock-based compensation		4,621																			4,621
Net tax benefit related to stock-based compensation		(1)														(1)
Other, net (shares)										(48,000)
Other, net		(1,313)														12								(1,325)
Ending balance (shares) at Dec. 31, 2016								0		35,673,000
Ending balance at Dec. 31, 2016		$ 1,093,298						$ 0		$ 366						898,989					(6,374)	217,494	9,766	(26,943)
Comprehensive income:
Treasury stock retired (in shares)		168,931
Net income		$ 55,247																				55,247
Other net comprehensive income (loss)		(5,605)																					(5,605)
Total comprehensive income		49,642																				55,247	(5,605)
Stock issued pursuant to acquisition (shares)									522,000						4,842,000
Stock issued pursuant to acquisition							$ 229,233		$ 40,633						$ 48					$ 188,552
Common stock issued (shares)										4,638,000
Common stock issued, net of $7.1 million offering costs		152,984								$ 46						152,938
Cash dividends declared on common shares		(33,022)																				(33,022)
Cash dividends declared on preferred shares		(219)																				(219)
Forfeited shares (shares)										(17,000)
Forfeited shares		0														102					516			(618)
Exercise of stock options (shares)										19,000
Exercise of stock options		329																				(158)		487
Restricted stock grants (shares)										161,000
Restricted stock grants		0														1,650					(5,775)			4,125
Stock-based compensation		5,102																			5,102
Other, net (shares)										(26,000)
Other, net		(1,083)														256						(163)		(1,176)
Ending balance (shares) at Dec. 31, 2017								522,000		45,290,000
Ending balance at Dec. 31, 2017		$ 1,496,264						$ 40,633		$ 460						$ 1,242,487					$ (6,531)	$ 239,179	$ 4,161	$ (24,125)
[1]	Treasury stock adjustment represents the extinguishment of 168,931 shares of Berkshire Hills Bancorp stock held by the Company's subsidiary.

CONSOLIDATED STATEMENTS OF CHA7

CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY (Parenthetical) - $ / shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Statement of Stockholders' Equity [Abstract]
Cash dividends declared, common stock (USD per share)	$ 0.84	$ 0.80	$ 0.76
Cash dividends declared, preferred stock (USD per share)	$ 0.42

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Cash flows from operating activities:
Net income	$ 55,247	$ 58,670	$ 49,518
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for loan losses	21,025	17,362	16,726
Net amortization of securities	1,678	4,052	3,010
Net change in unamortized loan origination costs and premium	2,232	(4,138)	(961)
Premises and equipment depreciation and amortization expense	9,916	8,393	8,594
Stock-based compensation expense	5,102	4,621	4,686
Accretion of purchase accounting entries, net	(18,189)	(9,407)	(10,074)
Amortization of other intangibles	3,493	2,927	3,563
Write down of other real estate owned	10	395	480
Excess tax loss from stock-based payment arrangements	0	(105)	(167)
Income from cash surrender value of bank-owned life insurance policies	(3,615)	(3,913)	(3,356)
(Loss) gain on sales of securities, net	(12,598)	551	(2,110)
Net (increase) decrease in loans held for sale	(32,947)	5,185	(3,212)
Loss on disposition of assets	912	1,318	3,514
(Gain) loss on sale of real estate	(51)	40	191
Amortization of tax credits	8,477	8,882	11,428
Remeasurement of deferred tax asset	18,145	0	0
Net change in other	19,254	3,309	4,458
Net cash provided by operating activities	78,091	98,142	86,288
Cash flows from investing activities:
Net decrease in trading security	632	599	570
Proceeds from sales of securities available for sale	188,921	421,843	41,169
Proceeds from maturities, calls and prepayments of securities available for sale	206,648	166,736	184,753
Purchases of securities available for sale	(498,646)	(400,053)	(285,637)
Proceeds from maturities, calls and prepayments of securities held to maturity	12,600	7,734	8,534
Purchases of securities held to maturity	(77,208)	(7,115)	(62,274)
Net change in loans	(468,331)	(334,347)	(388,091)
Acquisitions, net of cash paid	374,611	(48,180)	74,324
Net cash used for branch sale	0	0	(11,715)
Proceeds from surrender of bank-owned life insurance	310	258	554
Purchase of bank-owned life insurance	(20,000)	0	0
Proceeds from sale of Federal Home Loan Bank stock	96,378	19,461	2,357
Purchase of Federal Home Loan Bank stock	(88,351)	(19,555)	(10,706)
Proceeds from premises and equipment	0	226	2,261
Purchase of premises and equipment, net	(12,528)	(9,101)	(7,340)
Net investment in limited partnership tax credits	(5,102)	(7,616)	(5,105)
Payment to terminate cash flow hedges	6,573	0	0
Proceeds from sale of other real estate	590	1,515	1,854
Net cash used in investing activities	(282,903)	(207,595)	(454,492)
Cash flows from financing activities:
Net increase in deposits	418,550	140,730	475,823
Proceeds from Federal Home Loan Bank advances and other borrowings	5,978,358	9,364,599	8,566,300
Repayments of Federal Home Loan Bank advances and other borrowings	(6,174,781)	(9,365,159)	(8,620,064)
Issuance of common stock, net of $7.1 million offering costs	152,985	0	0
Purchase of treasury stock	0	0	(550)
Exercise of stock options	329	3,712	239
Excess tax loss from stock-based payment arrangements	0	0	167
Cash dividends paid	(33,241)	(24,916)	(21,903)
Acquisition contingent consideration paid	(1,700)	0	0
Net cash provided by financing activities	340,500	118,966	400,012
Net change in cash and cash equivalents	135,688	9,513	31,808
Cash and cash equivalents at beginning of year	113,075	103,562	71,754
Cash and cash equivalents at end of year	248,763	113,075	103,562
Supplemental cash flow information:
Interest paid on deposits	43,133	28,777	22,130
Interest paid on borrowed funds	21,336	16,674	9,974
Income taxes paid, net	18,323	16,229	429
Acquisition of non-cash assets and liabilities:
Assets acquired	1,584,786	1,169,086	948,796
Liabilities assumed	(1,959,489)	(965,529)	(762,261)
Other non-cash changes:
Other net comprehensive (loss) income	(5,605)	13,071	(9,884)
Real estate owned acquired in settlement of loans	$ 490	$ 340	$ 2,085

CONSOLIDATED STATEMENTS OF CAS9

CONSOLIDATED STATEMENTS OF CASH FLOWS (Parenthetical) $ in Millions	12 Months Ended
	Dec. 31, 2017USD ($)
Statement of Cash Flows [Abstract]
Offering costs	$ 7.1

SUMMARY OF SIGNIFICANT ACCOUNTI

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	12 Months Ended
	Dec. 31, 2017
Accounting Policies [Abstract]
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Basis of Presentation and Consolidation The consolidated financial statements (the “financial statements”) of Berkshire Hills Bancorp, Inc. and its subsidiaries (the “Company” or “Berkshire”) have been prepared in conformity with accounting principles generally accepted in the United States of America (“GAAP”). The Company is a Delaware corporation and the holding company for Berkshire Bank (the “Bank”), a Massachusetts-chartered trust company headquartered in Boston, Mass. These financial statements include the accounts of the Company, its wholly-owned subsidiaries and the Bank’s consolidated subsidiaries. In consolidation, all significant intercompany accounts and transactions are eliminated. The results of operations of companies or assets acquired are included only from the dates of acquisition. All material wholly-owned and majority-owned subsidiaries are consolidated unless GAAP requires otherwise. Reclassifications Certain items in prior financial statements have been reclassified to conform to the current presentation. The Company has evaluated subsequent events for potential recognition and/or disclosure through the date these consolidated financial statements were issued. Use of Estimates The preparation of 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 liabilities at the date of the financial statements. Actual results could differ from those estimates. Business Combinations Business combinations are accounted for using the acquisition method of accounting. Under this method, the accounts of an acquired entity are included with the acquirer’s accounts as of the date of acquisition with any excess of purchase price over the fair value of the net assets acquired (including identifiable intangibles) capitalized as goodwill. To consummate an acquisition, the Company will typically issue common stock and/or pay cash, depending on the terms of the acquisition agreement. The value of common shares issued is determined based upon the market price of the stock as of the closing of the acquisition. Cash and Cash equivalents Cash and cash equivalents include cash, balances due from banks, and short-term investments, all of which had an original maturity within 90 days. Due to the nature of cash and cash equivalents and the near term maturity, the Company estimated that the carrying amount of such instruments approximated fair value. The nature of the Bank’s business requires that it maintain amounts due from banks which at times, may exceed federally insured limits. The Bank has not experienced any losses on such amounts and all amounts are maintained with well-capitalized institutions. Trading Security The Company accounts for a tax advantaged economic development bond originated in 2008 at fair value, in accordance with Financial Accounting Standards Board’s (“FASB”) Accounting Standards Codification (“ASC”) 320. The bond has been designated as a trading account security and is recorded at fair value, with changes in unrealized gains and losses recorded through earnings each period as part of non-interest income. Securities Debt securities that management has the intent and ability to hold to maturity are classified as held to maturity and carried at amortized cost. All other securities, including equity securities with readily determinable fair values, are classified as available for sale and carried at fair value, with unrealized gains and losses reported as a component of other net comprehensive income. Management determines the appropriate classification of securities at the time of purchase. Restricted equity securities, such as stock in the Federal Home Loan Bank of Boston (“FHLBB”) are carried at cost. There are no quoted market prices for the Company’s restricted equity securities. The Bank is a member of the FHLBB, which requires that members maintain an investment in FHLBB stock, which may be redeemed based on certain conditions. The Bank reviews for impairment based on the ultimate recoverability of the cost bases in the FHLBB stock. Purchase premiums and discounts are recognized in interest income using the interest method over the terms of the securities. Gains and losses on the sale of securities are recorded on the trade date and are determined using the specific identification method. The Company evaluates debt and equity securities within the Company’s available for sale and held to maturity portfolios for other-than-temporary impairment (“OTTI”), at least quarterly. If the fair value of a debt security is below the amortized cost basis of the security, OTTI is required to be recognized if any of the following are met: (1) the Company intends to sell the security; (2) it is “more likely than not” that the Company will be required to sell the security before recovery of its amortized cost basis; or (3) the present value of expected cash flows is not sufficient to recover the entire amortized cost basis. For all impaired debt securities that the Company intends to sell, or more likely than not will be required to sell, the full amount of the depreciation is recognized as OTTI through earnings. Credit-related OTTI for all other impaired debt securities is recognized through earnings. Non-credit related OTTI for such debt securities is recognized in other comprehensive income, net of applicable taxes. In evaluating its marketable equity securities portfolios for OTTI, the Company considers its intent and ability to hold an equity security to recovery of its cost basis in addition to various other factors, including the length of time and the extent to which the fair value has been less than cost and the financial condition and near term prospects of the issuer. Any OTTI on marketable equity securities is recognized immediately through earnings. Loans Held for Sale Loans originated with the intent to be sold in the secondary market are accounted for under the fair value option. Non-refundable fees and direct loan origination costs related to residential mortgage loans held for sale are recognized in non-interest income or non-interest expense as earned or incurred. Fair value is primarily determined based on quoted prices for similar loans in active markets. Gains and losses on sales of residential mortgage loans (sales proceeds minus carrying value) are recorded in non-interest income. Loans that were previously held for investment that the Company has an active plan to sell are transferred to loans held for sale at the lower of cost or market (fair value). The market price is primarily determined based on quoted prices for similar loans in active markets or agreed upon sales prices. Gains are recorded in non-interest income at sale to the extent that the sale price of the loan exceeds carrying value. Any reduction in the loan’s value, prior to being transferred to loans held for sale, is reflected as a charge-off of the recorded investment in the loan resulting in a new cost basis, with a corresponding reduction in the allowance for loan losses. Further changes in the fair value of the loan are recognized in non-interest income or expense, accordingly. Loans Loans are reported at their outstanding unpaid principal balances adjusted for charge-offs, the allowance for loan losses, the unamortized balance of any deferred fees or costs on originated loans and the unamortized balance of any premiums or discounts on loans purchased or acquired through mergers. Interest income is accrued on the unpaid principal balance. Interest income includes net accretion or amortization of deferred fees or costs and of premiums or discounts. Direct loan origination costs, net of any origination fees, in addition to premiums and discounts on loans, are deferred and recognized as an adjustment of the related loan yield using the interest method. Interest on loans, excluding automobile loans, is generally not accrued on loans which are ninety days or more past due unless the loan is well-secured and in the process of collection. Past due status is based on contractual terms of the loan. Automobile loans generally continue accruing until one hundred and twenty days delinquent, at which time they are charged off. All interest accrued but not collected for loans that are placed on non-accrual or charged-off is reversed against interest income, except for certain loans designated as well-secured. The interest on non-accrual loans is accounted for on the cash-basis or cost-recovery method, until qualifying for return to accrual. All payments received on non-accrual loans are applied against the principal balance of the loan. Loans are returned to accrual status when all the principal and interest amounts contractually due are brought current and future payments are reasonably assured. Acquired Loans Loans that the Company acquired in acquisitions are initially recorded at fair value with no carryover of the related allowance for credit losses. Determining the fair value of the loans involves estimating the amount and timing of principal and interest cash flows initially expected to be collected on the loans and discounting those cash flows at an appropriate market rate of interest. For loans that meet the criteria stipulated in ASC 310-30, “ Loans and Debt Securities Acquired with Deteriorated Credit Quality, ” the Company recognizes the accretable yield, which is defined as the excess of all cash flows expected at acquisition over the initial fair value of the loan, as interest income on a level-yield basis over the expected remaining life of the loan. The excess of the loan’s contractually required payments over the cash flows expected to be collected is the nonaccretable difference. The nonaccretable difference is not recognized as an adjustment of yield, a loss accrual, or a valuation allowance. For ASC 310-30 loans, the expected cash flows reflect anticipated prepayments, determined on a loan by loan basis according to the anticipated collection plan of these loans. The expected prepayments used to determine the accretable yield are consistent between the cash flows expected to be collected and projections of contractual cash flows so as to not affect the nonaccretable difference. For ASC 310-30 loans, prepayments result in the recognition of the nonaccretable balance as current period yield. Changes in prepayment assumptions may change the amount of interest income and principal expected to be collected. Interest income is also net of recoveries recorded on acquired impaired loans. ASC310-30 loans that have similar risk characteristics, primarily credit risk, collateral type and interest rate risk, and are homogenous in size, are pooled and accounted for as a single asset with a single composite interest rate and an aggregate expectation of cash flows. ASC 310-30 loans that cannot be aggregated into a pool are accounted for individually. After we acquire loans determined to be accounted for under ASC 310-30, actual cash collections are monitored to determine if they conform to management’s expectations. Revised cash flow expectations are prepared each quarter. A decrease in expected cash flows in subsequent periods may indicate impairment and would require us to establish an allowance for loan and lease losses (“ALLL”) by recording a charge to the provision for loan and lease losses. An increase in expected cash flows in subsequent periods initially reduces any previously established ALLL by the increase in the present value of cash flows expected to be collected, and requires us to recalculate the amount of accretable yield for the ASC 310-30 loan or pool. The adjustment of accretable yield due to an increase in expected cash flows is accounted for as a change in estimate. The additional cash flows expected to be collected are reclassified from the nonaccretable difference to the accretable yield, and the amount of periodic accretion is adjusted accordingly over the remaining life of the ASC 310-30 loan or pool. An ASC 310-30 loan may be derecognized either through receipt of payment (in full or in part) from the borrower, the sale of the loan to a third party, foreclosure of the collateral, or charge-off. If one of these events occurs, the loan is removed from the loan pool, or derecognized if it is accounted for as an individual loan. ASC 310-30 loans subject to modification are not removed from an ASC 310-30 pool even if those loans would otherwise be deemed troubled debt restructurings (“TDRs”) since the pool, and not the individual loan, represents the unit of account. Individually accounted for ASC 310-30 loans that are modified in a TDR are no longer classified as ASC 310-30 loans and are subject to TDR recognition. Acquired loans that met the criteria for nonaccrual of interest prior to the acquisition are considered performing upon acquisition, regardless of whether the customer is contractually delinquent, if the Company can reasonably estimate the timing and amount of the expected cash flows on such loans and if the Company expects to fully collect the new carrying value of the loans. As such, the Company may no longer consider the loan to be nonaccrual or nonperforming and may accrue interest on these loans, including the impact of any accretable yield. The Company has determined that the Company can reasonably estimate future cash flows on the Company’s current portfolio of acquired loans that are past due 90 days or more and on which the Company is accruing interest and the Company expects to fully collect the carrying value of the loans. For loans that do not meet the ASC 310-30 criteria, the Company accretes interest income based on the contractually required cash flows. Subsequent to the purchase date, the methods utilized to estimate the required allowance for loan losses for these loans is similar to originated loans. Allowance for Loan Losses The allowance for loan losses is established based upon the level of estimated probable incurred losses in the current loan portfolio. Loan losses are charged against the allowance when management believes the collectability of a loan balance is doubtful. Subsequent recoveries, if any, are credited to the allowance. The allowance for loan losses includes allowance allocations calculated in accordance with ASC 310, “Receivables,” and allowance allocations calculated in accordance with ASC 450, “Contingencies.” The allowance for loan losses is allocated to loan types using both a formula-based approach applied to groups of loans and an analysis of certain individual loans for impairment. The formula-based approach emphasizes loss factors derived from actual historical and industry portfolio loss rates, which are combined with an assessment of certain qualitative factors to determine the allowance amounts allocated to the various loan categories. Allowance amounts are based on an estimate of historical average annual percentage rate of loan loss for each loan segment, a temporal estimate of the incurred loss emergence and confirmation period for each loan category, and certain qualitative risk factors considered in the computation of the allowance for loan losses. Qualitative risk factors impacting the inherent risk of loss within the portfolio include the following: • National and local economic conditions, regulatory/legislative changes, or other competitive factors affecting the collectability of the portfolio • Trends in underwriting characteristics, composition of the portfolio, and/or asset quality • Changes in underwriting standards and/or collection, charge off, recovery, and account management practice • The existence and effect of any concentrations of credit Risk characteristics relevant to each portfolio segment are as follows: Commercial real estate — Loans in this segment are primarily owner-occupied or income-producing properties throughout New England and Northeastern New York. The underlying cash flows generated by the properties are adversely impacted by a downturn in the economy, which in turn, will have an effect on the credit quality in this segment. Management monitors the cash flows of these loans. In addition, construction loans in this segment primarily include real estate development loans for which payment is derived from sale of the property or long term financing at completion. Credit risk is affected by cost overruns, time to sell at an adequate price, and market conditions Commercial and industrial loans — Loans in this segment are made to businesses and are generally secured by assets of the business. Repayment is expected from the cash flows of the business. Loans in this segment include asset based loans which generally have no scheduled repayment and which are closely monitored against formula based collateral advance ratios. A weakened economy, and resultant decreased consumer spending, will have an effect on the credit quality in this segment. Residential mortgage — All loans in this segment are collateralized by residential real estate and repayment is dependent on the credit quality of the individual borrower. The overall health of the economy, including unemployment rates and housing prices, will have an effect on the credit quality in this segment. Consumer loans — Loans in this segment are primarily home equity lines of credit and second mortgages, together with automobile loans and other consumer loans. The overall health of the economy, including unemployment rates and housing prices, will have an effect on the credit quality in this segment. The Company utilizes a blend of historical and industry portfolio loss rates for commercial real estate and commercial and industrial loans that are assessed by internal risk rating. Historical loss rates for residential mortgages, home equity and other consumer loans are not risk graded but are assessed based on the total of each loan segment. This approach incorporates qualitative adjustments based upon management’s assessment of various market and portfolio specific risk factors into its formula-based estimate. Due to the imprecise nature of the loan loss estimation process and ever changing conditions, the qualitative risk attributes may not adequately capture amounts of incurred loss in the formula-based loan loss components used to determine allocations in the Company’s analysis of the adequacy of the allowance for loan losses. The Company evaluates certain loans individually for specific impairment. Large groups of small balance homogeneous loans such as the residential mortgage, home equity, and other consumer portfolios are collectively evaluated for impairment. A loan is considered impaired when, based on current information and events, it is probable that the Company will be unable to collect the scheduled payments of principal or interest when due according to the contractual terms of the loan agreement. Factors considered by management in determining impairment include payment status, collateral value, and the probability of collecting scheduled principal and interest payments when due. Loans that experience insignificant payment delays and payment shortfalls generally are not classified as impaired. Loans are selected for evaluation based upon a change in internal risk rating, occurrence of delinquency, loan classification, or non-accrual status. The evaluation of certain loans individually for specific impairment includes non-accrual loans over a threshold and loans that were determined to be Troubled Debt Restructurings (“TDRs”). A specific allowance amount is allocated to an individual loan when such loan has been deemed impaired and when the amount of the probable loss is able to be estimated. Estimates of loss may be determined by the present value of anticipated future cash flows or the loan’s observable fair market value, or the fair value of the collateral less costs to sell, if the loan is collateral dependent. However, for collateral dependent loans, the amount of the recorded investment in a loan that exceeds the fair value of the collateral is charged-off against the allowance for loan losses in lieu of an allocation of a specific allowance amount when such an amount has been identified definitively as uncollectible. Regarding acquired loans, the Company subjects loans that do not meet the ASC 310-30 criteria to ASC 450-20 by collectively evaluating these loans for an allowance for loan loss. The Company applies a methodology similar to the methodology prescribed for business activities loans, which includes the application of environmental factors to each category of loans. The methodology to collectively evaluate the acquired loans outside the scope of ASC 310-30 includes the application of a number of environmental factors that reflect management’s best estimate of the level of incremental credit losses that might be recognized given current conditions. This is reviewed as part of the allowance for loan loss adequacy analysis. As the loan portfolio matures and environmental factors change, the loan portfolio will be reassessed each quarter to determine an appropriate reserve allowance. Additionally, the Company considers the need for an additional reserve for acquired loans accounted for outside of the scope of ASC 310-30 under ASC 310-20. At acquisition date, the Bank determined a fair value mark with credit and interest rate components. Under the Company’s model, the impairment evaluation process involves comparing the carrying value of acquired loans, including the unamortized premium or discount, to the calculated reserve allowance. If necessary, the Company books an additional reserve to account for shortfalls identified through this calculation. A decrease in the expected cash flows in subsequent periods requires the establishment of an allowance for loan losses at that time for ASC 310-30 loans. Bank-Owned Life Insurance Bank-owned life insurance policies are reflected on the consolidated balance sheets at cash surrender value. Changes in the net cash surrender value of the policies, as well as insurance proceeds received, are reflected in non-interest income on the consolidated statements of operations and are not subject to income taxes. Foreclosed and Repossessed Assets Other real estate owned is comprised of real estate acquired through foreclosure proceedings or acceptance of a deed in lieu of foreclosure. Repossessed collateral is primarily comprised of aircraft, motor vehicles, and taxi medallions. Both other real estate owned and repossessed collateral are held for sale and are initially recorded at the fair value less estimated costs to sell at the date of foreclosure or repossession, establishing a new cost basis. The shortfall, if any, of the loan balance over the fair value of the property or collateral, less cost to sell, at the time of transfer from loans to other real estate owned or repossessed collateral is charged to the allowance for loan losses. Subsequent to transfer, the asset is carried at lower of cost or fair value less cost to sell and periodically evaluated for impairment. Subsequent impairments in the fair value of other real estate owned and repossessed collateral are charged to expense in the period incurred. Net operating income or expense related to other real estate owned and repossessed collateral is included in operating expenses in the accompanying consolidated statements of income. Because of changing market conditions, there are inherent uncertainties in the assumptions with respect to the estimated fair value of other real estate owned and repossessed collateral. Because of these inherent uncertainties, the amount ultimately realized on other real estate owned and repossessed collateral may differ from the amounts reflected in the consolidated financial statements. Capitalized Servicing Rights Capitalized servicing rights are included in “other assets” in the consolidated balance sheet. Servicing assets are initially recognized as separate assets at fair value when rights are acquired through purchase or through sale of financial assets with servicing retained. The Company's servicing rights accounted for under the fair value method are carried on the consolidated balance sheet at fair value with changes in fair value recorded in income in the period in which the change occurs. Changes in the fair value of servicing rights are primarily due to changes in valuation inputs, assumptions, and the collection and realization of expected cash flows. The Company’s servicing rights accounted for under the amortization method are initially recorded at fair value. Under that method, capitalized servicing rights are charged to expense in proportion to and over the period of estimated net servicing income. Fair value of the servicing rights is based on a valuation model that calculates the present value of estimated future net servicing income. The valuation model incorporates assumptions that market participants would use in estimating future net servicing income, such as the cost to service, the discount rate, prepayment speeds and default rates and losses. Impairment is recognized through a valuation allowance for an individual tranche, to the extent that fair value is less than the capitalized amount for the tranches. If the Company later determines that all or a portion of the impairment no longer exists for a particular tranche, a reduction of the allowance may be recorded as an increase to income. Premises and Equipment Land is carried at cost. Buildings, improvements, and equipment are carried at cost less accumulated depreciation and amortization computed on the straight-line method over the estimated useful lives of the assets. Leasehold improvements are amortized on the straight-line method over the shorter of the lease term, plus optional terms if certain conditions are met, or the estimated useful life of the asset. Goodwill Goodwill represents the excess of the purchase price over the fair value of the net assets acquired in a business combination. Goodwill is assessed annually for impairment, and more frequently if events or changes in circumstances indicate that there may be an impairment. Adverse changes in the economic environment, declining operations, unanticipated competition, loss of key personnel, or other factors could result in a decline in the implied fair value of goodwill. If the implied fair value of goodwill is less than the carrying amount, a loss would be recognized in other non-interest expense to reduce the carrying amount to the implied fair value of goodwill. The Company performs an annual qualitative assessment of whether it is more likely than not that the reporting unit's fair value is less than its carrying amount. If the results of the qualitative assessment suggest goodwill impairment, the Company would perform a two-step impairment test through the application of various quantitative valuation methodologies. Step 1, used to identify instances of potential impairment, compares the fair value of the reporting unit with its carrying amount, including goodwill. If the carrying amount, including goodwill, exceeds its fair value, the second step of the goodwill impairment analysis is performed to measure the amount of impairment loss, if any. Step 2 of the goodwill impairment analysis compares the implied fair value of reporting unit goodwill with the carrying amount of that goodwill. If the carrying amount of goodwill for the reporting unit exceeds the implied fair value of the reporting unit’s goodwill, an impairment loss is recognized in an amount equal to that excess. Subsequent reversals of goodwill impairment are prohibited. The Company may elect to bypass the qualitative assessment and begin with Step 1. Other Intangibles Intangible assets are acquired assets that lack physical substance but can be distinguished from goodwill because of contractual or other legal rights or the asset is capable of being sold or exchanged either on its own or in combination with a related contract, asset or liability. The fair values of these assets are generally determined based on appraisals and are subsequently amortized on a straight-line basis or an accelerated basis over their estimated lives. Management assesses the recoverability of these intangible assets whenever events or changes in circumstances indicate that their carrying value may not be recoverable. If the carrying amount exceeds fair value, an impairment charge is recorded to income. Transfers of Financial Assets Transfers of an entire financial asset, group of entire financial assets, or a participating interest in an entire financial asset are accounted for as sales when control over the assets has been surrendered. Control over transferred assets is deemed to be surrendered when (1) the assets have been isolated from the Company, (2) the transferee obtains the right to pledge or exchange the transferred assets, and (3) the Company does not maintain effective control over the transferred assets. Income Taxes Deferred income taxes are recognized for the tax consequences of temporary differences by applying enacted statutory tax rates applicable for future years to differences between financial statement and tax bases of existing assets and liabilities. The effect of tax rate changes on deferred taxes is recognized in the income tax provision in the period that includes the enactment date. A tax valuation allowance is established, as needed, to reduce net deferred tax assets to the amount expected to be realized. In the event it becomes more likely than not that some or all of the deferred tax asset allowances will not be needed, the valuation allowance will be adjusted. In the ordinary course of business there is inherent uncertainty in quantifying the Company’s income tax positions. Income tax positions and recorded tax benefits are based upon management’s evaluation of the facts, circumstances, and information available at the reporting date. For those tax positions where it is more likely than not that a tax benefit will be sustained, we have determined the amount of the tax benefit to be recognized by estimating the largest amount of tax benefit that has a greater than 50% likelihood of being realized upon ultimate settlement with a taxing authority that has full knowledge of all relevant information. For those income tax positions where it is more-likely-than-not that a tax benefit will not be sustained, no tax benefit has been recognized in the financial statements. Where applicable, associated interest and penalties have also been recognized. We recognize accrued interest and penalties related to unrecognized tax benefits as a component of income tax expense. Insurance Commissions Commission revenue is recognized as of the effective date of the insurance policy or the date the customer is billed, whichever is later, net of return commissions related to policy cancellations. In addition, the Company may receive additional performance commissions based on achieving certain sales and loss experience measures. Such commissions are recognized when determinable, which is generally when such commissions are received or when the Company receives data from the insurance companies that allows the reasonable estimation of these amounts. Advertising Costs Advertising costs are expensed as incurred. Stock-Based Compensation The Company measures and recognizes compensation cost relating to share-based payment transactions based on the grant-date fair value of the equity instruments issued. The fair value of restricted stock is recorded as unearned compensation. The deferred expense is amortized to compensation expense based on one of several permitted attribution methods over the longer of the required service period or performance period. For performance-based restricted stock 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. Income tax benefits and/or tax deficiencies related to stock compensation determined as the difference between compensation cost recognized for financial reporting purposes and the deduction for tax, are recognized in the income statement as income tax expense or benefit in the period in which they occur. Wealth Management Wealth management assets held in a fiduciary or agent capacity are not included in the accompanying consolidated balance sheets because they are not assets of the Company. Fees earned from wealth management activities are amortized over the pe

ACQUISITIONS

ACQUISITIONS	12 Months Ended
	Dec. 31, 2017
Business Combinations [Abstract]
ACQUISITIONS	ACQUISITIONS Commerce Bank At the close of business on October 13, 2017, the Company completed the acquisition of Commerce Bancshares Corp. (“Commerce”), the parent company of Commerce Bank & Trust Company (“Commerce Bank”). Commerce Bank also merged with and into Berkshire Bank. Headquartered in Worcester, Mass., Commerce Bank operated 16 branch banking offices providing a range of services in Central Massachusetts and greater Boston. With this agreement, the Company established a market position in Worcester, New England’s second largest city. Additionally, this acquisition was a catalyst for the Company’s decision to relocate its corporate headquarters to Boston and to expand its Greater Boston market initiatives. This acquisition also increased the Company’s total assets over the $10 billion Dodd Frank Act threshold for additional regulatory requirements. As established by the merger agreement, each of the 6.328 million outstanding shares of Commerce common stock was converted into the right to receive 0.93 shares of the Company's common stock, plus cash in lieu of fractional shares. Certain Commerce common stock was instead converted into the right to receive 0.465 shares of new Series B preferred stock (non-voting) issued by the Company, pursuant to limited circumstances established by the merger agreement. Each preferred share is convertible into two shares of the Company's common stock under specified conditions. As of close of business on October 13, 2017, the Company issued 4.842 million common shares and 522 thousand preferred shares as merger consideration, pursuant to the merger agreement. The value of this consideration was measured at $188.6 million for the common stock and $40.6 million for the preferred stock based on the $38.95 closing price of the Company’s common stock on the issuance date. Pursuant to the Merger Agreement, the Commerce Bancshares 2010 Long-Term Incentive Plan was terminated prior to the acquisition date and the holder of a phantom stock award, whether or not vested, received an amount of cash determined by multiplying (i) the excess, if any, of $34.00 less the applicable per share exercise price of that Commerce phantom stock award by (ii) the number of shares of Commerce common stock subject to that Commerce phantom stock award, less any required tax withholding. Prior to the effective time of the merger, Commerce accelerated and repaid in full the Commerce subordinated debt per the merger agreement. The acquisition was accounted for under the acquisition method of accounting in accordance with ASC Topic 805, Business Combinations. Accordingly, the Company recognizes amounts for identifiable assets acquired and liabilities assumed at their estimated acquisition date fair value, with any excess of purchase consideration over the net assets being reported as goodwill. Due to the complexity in valuing the acquired loans and the significant amount of data inputs required, the valuation of the loans is not yet final. Fair value estimates are based on the information available, and are subject to change for up to one year after the closing date of the acquisition as additional information relative to the closing date fair values becomes available. Management continues to review initial estimates on certain areas such as loan valuations and the deferred tax asset. The following table provides a summary of the assets acquired and liabilities assumed and the associated fair value adjustments as recorded by the Company at acquisition: Fair Value As Recorded by (in thousands) As Acquired Adjustments the Company Consideration Paid: Company common stock issued to Commerce common shareholders $ 188,599 Company preferred stock issued to certain Commerce shareholders 40,633 Cash in lieu paid to Commerce shareholders 1 Total consideration paid $ 229,233 Recognized amounts of identifiable assets acquired and (liabilities) assumed, at fair value: Cash and short-term investments $ 374,611 $ — $ 374,611 Investment securities 115,274 (1,427 ) (a) 113,847 Loans, net 1,327,256 (86,505 ) (b) 1,240,751 Premises and equipment 8,931 5,346 (c) 14,277 Core deposit intangibles — 22,400 (d) 22,400 Deferred tax assets, net 7,956 26,580 (e) 34,536 Goodwill and other intangibles 11,233 (11,233 ) (f) — Other assets 52,709 (3,664 ) (g) 49,045 Deposits (1,710,872 ) (1,180 ) (h) (1,712,052 ) Borrowings (19,542 ) — (19,542 ) Other liabilities (5,086 ) 265 (4,821 ) Total identifiable net assets $ 162,470 $ (49,418 ) $ 113,052 Goodwill $ 116,181 ________________________________ Explanation of Certain Fair Value Adjustments (a) The adjustment represents the write down of the book value of securities to their estimated fair value at the date of acquisition. (b) The adjustment represents the write-off of $15.0 million in allowance for loan and lease losses and the write down of the book value of loans to their estimated fair value based on interest rates and expected cash flows as of the acquisition date, which includes an estimate of expected loan loss inherent in the portfolio. The valuation of the loans is provisional. Loans with evidence of credit deterioration at acquisition are accounted for under ASC 310-30 and had a book value of $163.1 million and had a fair value of $71.1 million . Non-impaired loans accounted for under ASC 310-20 had a book value of $1.18 billion and have a fair value of $1.17 billion . ASC 310-30 loans have a $10.8 million fair value adjustment that is accretable in earnings. ASC 310-20 loans have a $4.0 million fair value adjustment premium that is amortized over the remaining term of the loans using the effective interest method, or a straight-line method if the loan is a revolving credit facility. (c) The adjustment represents an increased fair value based on the appraised value of Commerce’s owned branches and headquarters comprised of $5.7 million for buildings and $0.7 million for land. This was offset by a $1.0 million reduction of the book value of furniture, fixtures, and equipment, to their estimated fair value and the immediate expensing of equipment not meeting the thresholds for capitalization in accordance with Company policy. The adjustments will be depreciated over the remaining estimated economic lives of the assets. (d) The adjustment represents the value of the core deposit base assumed in the acquisition. The core deposit asset was recorded as an identifiable intangible asset and will be amortized over the estimated useful life of the deposit base ( 10 years ). (e) Represents net deferred tax assets resulting from the fair value adjustments related to the acquired assets and liabilities, identifiable intangibles, and other purchase accounting adjustments. (f) Represents the write-off of goodwill and intangible assets from a prior Commerce acquisition. (g) The adjustment includes a $3.5 million write-down of repossessed assets based on market report data. (h) The adjustment is necessary because the weighted average interest rate of time deposits exceeded the cost of similar funding at the time of acquisition. The amount will be amortized over the estimated useful life of nine months. Except for collateral dependent loans with deteriorated credit quality, the fair values for loans acquired were estimated using cash flow projections based on the remaining maturity and repricing terms. Cash flows were adjusted by estimating future credit losses and the rate of prepayments. Projected monthly cash flows were then discounted to present value using a risk-adjusted market rate for similar loans. For collateral dependent loans with deteriorated credit quality, the Company estimated fair value by analyzing the value of the underlying collateral of the loans, assuming the fair values of the loans were derived from the eventual sale of the collateral. Those values were discounted using market derived rates of return, with consideration given to the period of time and costs associated with the foreclosure and disposition of the collateral. There was no carryover of the seller’s allowance for credit losses associated with the loans acquired, as the loans were initially recorded at fair value. Provisional information about the Commerce Bank acquired loan portfolio subject to ASC 310-30 as of October 13, 2017 is as follows (in thousands): ASC 310-30 Loans Gross contractual receivable amounts at acquisition $ 163,125 Contractual cash flows not expected to be collected (nonaccretable discount) (81,205 ) Expected cash flows at acquisition 81,920 Interest component of expected cash flows (accretable discount) (10,815 ) Fair value of acquired loans $ 71,105 Capitalized goodwill, which is not amortized for book purposes, is not deductible for tax purposes. Direct acquisition and integration costs of the Commerce Bank acquisition were expensed as incurred, and totaled $17.8 million during the twelve months ending December 31, 2017 and there were none for the same period of 2016. Pro Forma Information (unaudited) The following table presents selected unaudited pro forma financial information reflecting the acquisition of Commerce assuming the acquisition was completed as of January 1, 2016. The unaudited pro forma financial information includes adjustments for scheduled amortization and accretion of fair value adjustments. These adjustments would have been different if they had been recorded on January 1, 2016, and they do not include the impact of prepayments. The unaudited pro forma financial information is presented for illustrative purposes only and is not necessarily indicative of the combined financial results of the Company and the acquisition had the transaction actually been completed at the beginning of the periods presented, nor does it indicate future results for any other interim or full-year period. The unaudited pro forma information is based on the actual financial statements of Berkshire and the acquired business for the periods shown until the dates of acquisition, at which time the acquired business operations became included in Berkshire’s financial statements. For whole-bank acquisitions, the Company has determined it is impractical to report the amounts of revenue and earnings of each entity since acquisition date. Due to the integration of their operations with those of the organization, the Company does not record revenue and earnings separately. The revenue and earnings of Commerce’s operations are included in the Consolidated Statement of Income. The unaudited pro forma information, for the twelve months ended December 31, 2017 and 2016, set forth below reflects adjustments related to (a) amortization and accretion of purchase accounting fair value adjustments; (b) amortization of core deposit and customer relationship intangibles; and (c) an estimated tax rate of 40 percent . Direct acquisition expenses incurred by the Company during 2017, as noted above, are reversed for the purposes of this unaudited pro forma information. Furthermore, the unaudited pro forma information does not reflect management’s estimate of any revenue-enhancing or anticipated cost-savings that could occur as a result of the acquisition. Information in the following table is shown in thousands, except earnings per share: Pro Forma (unaudited) 2017 2016 Net interest income $ 344,797 $ 302,012 Non-interest income 134,818 77,192 Income available to common shareholders 77,340 78,859

CASH AND CASH EQUIVALENTS

CASH AND CASH EQUIVALENTS	12 Months Ended
	Dec. 31, 2017
Cash and Cash Equivalents [Abstract]
CASH AND CASH EQUIVALENTS	CASH AND CASH EQUIVALENTS Cash and cash equivalents include cash on hand, amounts due from banks, and short-term investments with original maturities of 90 days or less. Short-term investments included $2.1 million and $0.9 million pledged as collateral support for derivative financial contracts at year-end 2017 and 2016, respectively. The Federal Reserve Bank requires the Bank to maintain certain reserve requirements of vault cash and/or deposits. The reserve requirement, included in cash and equivalents, was $20.4 million and $17.0 million at year-end 2017 and 2016, respectively.

TRADING SECURITY

TRADING SECURITY	12 Months Ended
	Dec. 31, 2017
Trading Securities [Abstract]
TRADING SECURITY	TRADING SECURITY The Company holds a tax advantaged economic development bond that is being accounted for at fair value. The security had an amortized cost of $10.8 million and $11.4 million and a fair value of $12.3 million and $13.2 million at year-end 2017 and 2016, respectively. Unrealized (losses) gains recorded through income on this security totaled ($0.3) million , ($0.4) million , and ($0.2) million for 2017, 2016, and 2015, respectively. As discussed further in Note 16 - Derivative Instruments and Hedging Activities, the Company has entered into a swap contract to swap-out the fixed rate of the security in exchange for a variable rate. The Company does not purchase securities with the intent of selling them in the near term, and there are no other securities in the trading portfolio at year-end 2017 and 2016.

SECURITIES

SECURITIES	12 Months Ended
	Dec. 31, 2017
Investments, Debt and Equity Securities [Abstract]
SECURITIES	SECURITIES The following is a summary of securities available for sale (“AFS”) and securities held to maturity (“HTM”): (In thousands) Amortized Gross Gross Fair Value December 31, 2017 Securities available for sale Debt securities: Municipal bonds and obligations $ 113,427 $ 5,012 $ (206 ) $ 118,233 Agency collateralized mortgage obligations 859,705 397 (8,944 ) 851,158 Agency mortgage-backed securities 218,926 279 (2,265 ) 216,940 Agency commercial mortgage-backed securities 64,025 41 (1,761 ) 62,305 Corporate bonds 110,076 882 (237 ) 110,721 Trust preferred securities 11,334 343 — 11,677 Other bonds and obligations 9,757 154 (31 ) 9,880 Total debt securities 1,387,250 7,108 (13,444 ) 1,380,914 Marketable equity securities 36,483 9,211 (509 ) 45,185 Total securities available for sale 1,423,733 16,319 (13,953 ) 1,426,099 Securities held to maturity Municipal bonds and obligations 270,310 8,675 (90 ) 278,895 Agency collateralized mortgage obligations 73,742 1,045 (486 ) 74,301 Agency mortgage-backed securities 7,892 — (164 ) 7,728 Agency commercial mortgage-backed securities 10,481 — (268 ) 10,213 Tax advantaged economic development bonds 34,357 596 (1,135 ) 33,818 Other bonds and obligations 321 — — 321 Total securities held to maturity 397,103 10,316 (2,143 ) 405,276 Total $ 1,820,836 $ 26,635 $ (16,096 ) $ 1,831,375 December 31, 2016 Securities available for sale Debt securities: Municipal bonds and obligations $ 117,910 $ 2,955 $ (1,049 ) $ 119,816 Agency collateralized mortgage obligations 652,680 2,522 (3,291 ) 651,911 Agency mortgage-backed securities 230,308 557 (2,181 ) 228,684 Agency commercial mortgage-backed securities 65,673 229 (1,368 ) 64,534 Corporate bonds 56,320 408 (722 ) 56,006 Trust preferred securities 11,578 368 (59 ) 11,887 Other bonds and obligations 10,979 195 (16 ) 11,158 Total debt securities 1,145,448 7,234 (8,686 ) 1,143,996 Marketable equity securities 47,858 19,296 (1,613 ) 65,541 Total securities available for sale 1,193,306 26,530 (10,299 ) 1,209,537 Securities held to maturity Municipal bonds and obligations 203,463 3,939 (2,416 ) 204,986 Agency collateralized mortgage-backed securities 75,655 1,281 (411 ) 76,525 Agency mortgage-backed securities 9,102 — (243 ) 8,859 Agency commercial mortgage-backed securities 10,545 — (434 ) 10,111 Tax advantaged economic development bonds 35,278 1,596 — 36,874 Other bonds and obligations 325 — — 325 Total securities held to maturity 334,368 6,816 (3,504 ) 337,680 Total $ 1,527,674 $ 33,346 $ (13,803 ) $ 1,547,217 At year-end 2017 and 2016, accumulated net unrealized gains on AFS securities included in accumulated other comprehensive income were $2.3 million and $16.2 million , respectively. At year-end 2017 and 2016, accumulated net unrealized gains on HTM securities included in accumulated other comprehensive income were $7.7 million and $9.0 million respectively. The year-end 2017 and 2016 related income tax benefit of $4.0 million and $9.6 million , respectively, was also included in accumulated other comprehensive income. The amortized cost and estimated fair value of available for sale (AFS) and held to maturity (HTM) securities, segregated by contractual maturity at year-end 2017 are presented below. Expected maturities may differ from contractual maturities because issuers may have the right to call or prepay obligations. Mortgage-backed securities and collateralized mortgage obligations are shown in total, as their maturities are highly variable. Equity securities have no maturity and are also shown in total. Available for sale Held to maturity (In thousands) Amortized Fair Amortized Fair Within 1 year $ 622 $ 623 $ 1,261 $ 1,261 Over 1 year to 5 years 32,659 32,972 25,892 26,422 Over 5 years to 10 years 75,261 76,745 8,752 8,917 Over 10 years 136,052 140,171 269,083 276,434 Total bonds and obligations 244,594 250,511 304,988 313,034 Marketable equity securities 36,483 45,185 — — Mortgage-backed securities 1,142,656 1,130,403 92,115 92,242 Total $ 1,423,733 $ 1,426,099 $ 397,103 $ 405,276 At year-end 2017 and 2016, the Company had pledged securities as collateral for certain municipal deposits and for interest rate swaps with certain counterparties. The total amortized cost and fair values of these pledged securities follows. Additionally, there is a blanket lien on certain securities to collateralize borrowings from the FHLBB, as discussed further in Note 12 - Borrowed Funds. 2017 2016 (In thousands) Amortized Fair Amortized Fair Securities pledged to swap counterparties $ 24,410 $ 24,240 $ 51,292 $ 51,290 Securities pledged for municipal deposits 210,382 214,513 147,950 148,435 Total $ 234,792 $ 238,753 $ 199,242 $ 199,725 Proceeds from the sale of AFS securities in 2017, 2016, and 2015 were $188.9 million , $421.8 million , and $41.2 million , respectively. The components of net realized gains and losses on the sale of AFS securities are as follows. These amounts were reclassified out of accumulated other comprehensive income and into earnings: (In thousands) 2017 2016 2015 Gross realized gains $ 13,877 $ 2,762 $ 4,567 Gross realized losses (1,279 ) (3,313 ) (2,457 ) Net realized gains/(losses) $ 12,598 $ (551 ) $ 2,110 Securities with unrealized losses, segregated by the duration of their continuous unrealized loss positions, are summarized as follows: Less Than Twelve Months Over Twelve Months Total (In thousands) Gross Fair Gross Fair Gross Fair December 31, 2017 Securities available for sale Debt securities: Municipal bonds and obligations $ — $ — $ 206 $ 8,985 $ 206 $ 8,985 Agency collateralized mortgage obligations 6,849 655,479 2,095 80,401 8,944 735,880 Agency mortgage-backed securities 765 95,800 1,500 65,323 2,265 161,123 Agency commercial mortgage-back securities 334 17,379 1,427 39,268 1,761 56,647 Corporate bonds 1 328 236 15,769 237 16,097 Trust preferred securities — — — — — — Other bonds and obligations 11 1,096 20 2,004 31 3,100 Total debt securities 7,960 770,082 5,484 211,750 13,444 981,832 Marketable equity securities 509 3,731 — — 509 3,731 Total securities available for sale $ 8,469 $ 773,813 $ 5,484 $ 211,750 $ 13,953 $ 985,563 Securities held to maturity Municipal bonds and obligations 35 10,213 55 2,059 90 12,272 Agency collateralized mortgage obligations — — 486 12,946 486 12,946 Agency mortgage-backed securities — — 164 7,728 164 7,728 Agency commercial mortgage-back securities — — 268 10,213 268 10,213 Tax advantaged economic development bonds 1,135 7,305 — — 1,135 7,305 Total securities held to maturity 1,170 17,518 973 32,946 2,143 50,464 Total $ 9,639 $ 791,331 $ 6,457 $ 244,696 $ 16,096 $ 1,036,027 December 31, 2016 Securities available for sale Debt securities: Municipal bonds and obligations $ 1,049 $ 13,839 $ — $ — $ 1,049 $ 13,839 Agency collateralized mortgage obligations 3,291 319,448 — — 3,291 319,448 Agency mortgage-backed securities 2,153 130,766 28 2,061 2,181 132,827 Agency commercial mortgage-backed securities 1,368 44,860 — — 1,368 44,860 Corporate bonds 11 4,780 711 19,655 722 24,435 Trust preferred securities — — 59 1,204 59 1,204 Other bonds and obligations 15 3,014 1 27 16 3,041 Total debt securities 7,887 516,707 799 22,947 8,686 539,654 Marketable equity securities 157 6,600 1,456 5,927 1,613 12,527 Total securities available for sale $ 8,044 $ 523,307 $ 2,255 $ 28,874 $ 10,299 $ 552,181 Securities held to maturity Municipal bonds and obligations 2,416 69,308 — — 2,416 69,308 Agency collateralized mortgage obligations 411 14,724 — — 411 14,724 Agency mortgage-backed securities 243 8,859 — — 243 8,859 Agency commercial mortgage-back securities 434 10,111 — — 434 10,111 Total securities held to maturity 3,504 103,002 — — 3,504 103,002 Total $ 11,548 $ 626,309 $ 2,255 $ 28,874 $ 13,803 $ 655,183 Debt Securities The Company expects to recover its amortized cost basis on all debt securities in its AFS and HTM portfolios. Furthermore, the Company does not intend to sell nor does it anticipate that it will be required to sell any of its securities in an unrealized loss position as of December 31, 2017, prior to this recovery. The Company’s ability and intent to hold these securities until recovery is supported by the Company’s strong capital and liquidity positions as well as its historical low portfolio turnover. The following summarizes, by investment security type, the basis for the conclusion that the debt securities in an unrealized loss position within the Company’s AFS and HTM portfolios did not maintain other-than-temporary impairment ("OTTI") at year-end 2017: AFS municipal bonds and obligations At year-end 2017, 6 out of the total 260 securities in the Company’s portfolio of AFS municipal bonds and obligations were in unrealized loss positions. Aggregate unrealized losses represented 2.3% of the amortized cost of securities in unrealized loss positions. The Company continually monitors the municipal bond sector of the market carefully and periodically evaluates the appropriate level of exposure to the market. At this time, the Company feels that the bonds in this portfolio carry minimal risk of default and that the Company is appropriately compensated for that risk. There were no material underlying credit downgrades during 2017. All securities are performing. AFS collateralized mortgage obligations At year-end 2017, 179 out of the total 234 securities in the Company’s portfolio of AFS collateralized mortgage obligations were in unrealized loss positions. Aggregate unrealized losses represented 1.2% of the amortized cost of securities in unrealized loss positions. The Federal National Mortgage Association ("FNMA"), Federal Home Loan Mortgage Corporation ("FHLMC"), and Government National Mortgage Association ("GNMA") guarantee the contractual cash flows of all of the Company's collateralized residential mortgage obligations. The securities are investment grade rated and there were no material underlying credit downgrades during 2017. All securities are performing. AFS commercial and residential mortgage-backed securities At year-end 2017, 58 out of the total 103 securities in the Company’s portfolio of AFS mortgage-backed securities were in unrealized loss positions. Aggregate unrealized losses represented 1.8% of the amortized cost of securities in unrealized loss positions. The FNMA, FHLMC, and GNMA guarantee the contractual cash flows of the Company’s mortgage-backed securities. The securities are investment grade rated and there were no material underlying credit downgrades during 2017. All securities are performing. AFS corporate bonds At year-end 2017, 1 out of the total 20 securities in the Company’s portfolio of AFS corporate bonds were in unrealized loss positions. The aggregate unrealized loss represents 1.5% of the amortized cost of bonds in unrealized loss positions. The Company reviews the financial strength of these bonds and has concluded that the amortized cost remains supported by the expected future cash flows of these securities. AFS other bonds and obligations At year-end 2017, 6 out of the total 9 securities in the Company’s portfolio of other bonds and obligations were in unrealized loss positions. Aggregate unrealized losses represented 1.0% of the amortized cost of securities in unrealized loss positions. The securities are all investment grade rated, and there were no material underlying credit downgrades during 2017. All securities are performing. HTM Municipal bonds and obligations At year-end 2017, 12 out of the total 231 securities in the Company’s portfolio of HTM municipal bonds and obligations were in unrealized loss positions. Aggregate unrealized losses represented 0.7% of the amortized cost of securities in unrealized loss positions. The Company continually monitors the municipal bond sector of the market carefully and periodically evaluates the appropriate level of exposure to the market. At this time, the Company feels that the bonds in this portfolio carry minimal risk of default and that the Company is appropriately compensated for that risk. There were no material underlying credit downgrades during 2017. All securities are performing. HTM collateralized mortgage obligations At year-end 2017, 1 out of the total 9 securities in the Company’s portfolio of HTM collateralized mortgage obligations was in unrealized loss positions. Aggregate unrealized losses represented 3.6% of the amortized cost of securities in unrealized loss positions. The FNMA, FHLMC, and GNMA guarantee the contractual cash flows of all of the Company's collateralized residential mortgage obligations. The securities are investment grade rated, and there were no material underlying credit downgrades during 2017. All securities are performing. HTM commercial and residential mortgage-backed securities At year-end 2017, 2 out of the total 2 securities in the Company’s portfolio of HTM mortgage-backed securities were in unrealized loss positions. Aggregate unrealized losses represented 2.4% of the amortized cost of securities in unrealized loss positions. The FNMA, FHLMC, and GNMA guarantees the contractual cash flows of the Company’s mortgage-backed securities. The securities are investment grade rated and there were no material underlying credit downgrades during 2017. All securities are performing. HTM tax-advantaged economic development bonds At year-end 2017, 1 out of the total 7 securities in the Company’s portfolio of tax advantaged economic development bonds were in an unrealized loss position. Aggregate unrealized losses represented 13.4% of the amortized cost of the security in an unrealized loss position. The above mentioned tax advantaged economic bond was downgraded to special mention during the year. The Company believes that more likely than not all the principal outstanding will be collected. All securities are performing. Marketable Equity Securities In evaluating its marketable equity securities portfolio for OTTI, the Company considers its ability to more likely than not hold an equity security to recovery. The Company additionally considers other various factors including the length of time and the extent to which the fair value has been less than cost and the financial condition and near term prospects of the issuer. Any OTTI is recognized immediately through earnings. At year-end 2017, 2 out of the total 20 securities in the Company’s portfolio of marketable equity securities were in unrealized loss positions. The unrealized loss represented 11.3% of the amortized cost of the securities. The Company has the ability and intent to hold the securities until a recovery of their cost basis and does not consider the securities other-than-temporarily impaired at year-end 2017. As new information becomes available in future periods, changes to the Company’s assumptions may be warranted and could lead to a different conclusion regarding the OTTI of these securities.

LOANS

LOANS	12 Months Ended
	Dec. 31, 2017
Receivables [Abstract]
LOANS	LOANS The Company’s loan portfolio is segregated into the following segments: commercial real estate, commercial and industrial, residential mortgage, and consumer. Commercial real estate loans include construction, single and multi-family, and other commercial real estate classes. Residential mortgage loans include classes for 1-4 family owner occupied and construction loans. Consumer loans include home equity, direct and indirect auto, and other consumer loan classes. These portfolio segments each have unique risk characteristics that are considered when determining the appropriate level for the allowance for loan losses. A substantial portion of the loan portfolio is secured by real estate in Massachusetts, southern Vermont, northeastern New York, New Jersey, and in the Bank’s other New England lending areas. The ability of many of the Bank’s borrowers to honor their contracts is dependent, among other things, on the specific economy and real estate markets of these areas. Total loans include business activity loans and acquired loans. Acquired loans are those loans acquired from Commerce Bank, First Choice Bank, Parke Bank, Firestone Financial Corp., Hampden Bancorp, Inc., the New York branch acquisition, Beacon Federal Bancorp, Inc., The Connecticut Bank and Trust Company, Legacy Bancorp, Inc., and Rome Bancorp, Inc. Once the full integration of the acquired entity is complete, acquired and business activity loans are serviced, managed, and accounted for under the Company's same control environment. The following is a summary of total loans: December 31, 2017 December 31, 2016 (In thousands) Business Activities Loans Acquired Loans Total Business Activities Loans Acquired Loans Total Commercial real estate: Construction $ 181,371 $ 84,965 $ 266,336 $ 253,302 $ 34,207 $ 287,509 Single and multi-family 217,083 206,082 423,165 191,819 125,672 317,491 Other commercial real estate 1,819,253 755,988 2,575,241 1,481,223 530,215 2,011,438 Total commercial real estate 2,217,707 1,047,035 3,264,742 1,926,344 690,094 2,616,438 Commercial and industrial loans 1,182,569 621,370 1,803,939 908,102 153,936 1,062,038 Total commercial loans 3,400,276 1,668,405 5,068,681 2,834,446 844,030 3,678,476 Residential mortgages: 1-4 family 1,808,024 289,373 2,097,397 1,583,794 297,355 1,881,149 Construction 5,177 233 5,410 11,178 804 11,982 Total residential mortgages 1,813,201 289,606 2,102,807 1,594,972 298,159 1,893,131 Consumer loans: Home equity 294,954 115,227 410,181 313,521 80,279 393,800 Auto and other 603,767 113,902 717,669 478,368 106,012 584,380 Total consumer loans 898,721 229,129 1,127,850 791,889 186,291 978,180 Total loans $ 6,112,198 $ 2,187,140 $ 8,299,338 $ 5,221,307 $ 1,328,480 $ 6,549,787 Total unamortized net costs and premiums included in the year-end total loans for business activity loans were the following: (In thousands) December 31, 2017 December 31, 2016 Unamortized net loan origination costs $ 24,669 $ 21,972 Unamortized net premium on purchased loans 4,311 4,849 Total unamortized net costs and premiums $ 28,980 $ 26,821 The Company occasionally transfers a portion of its originated commercial loans to participating lending partners. The amounts transferred have been accounted for as sales and are therefore not included in the Company’s accompanying consolidated balance sheets. The Company and its lending partners share proportionally in any gains or losses that may result from a borrower’s lack of compliance with contractual terms of the loan. The Company continues to service the loans, collects cash payments from the borrowers, remits payments (net of servicing fees), and disburses required escrow funds to relevant parties. At year-end 2017 and 2016, the Company was servicing loans for participants totaling $1.8 billion and $0.5 billion , respectively. In 2017, the Company purchased loans aggregating $500.9 million and sold loans aggregating $514.5 million . In 2016, the Company purchased loans aggregating $190.8 million and sold loans aggregating $307.7 million . Net gains (losses) on sales of loans were $11.7 million , $8.0 million , and $6.0 million for the years 2017, 2016, and 2015, respectively. These amounts are included in Loan Related Income on the Consolidated Statement of Income. Most of the Company’s lending activity occurs within its primary markets in Massachusetts, Southern Vermont, and Northeastern New York. Most of the loan portfolio is secured by real estate, including residential mortgages, commercial mortgages, and home equity loans. Year-end loans to operators of non-residential buildings totaled $1.3 billion , or 15.8% , and $1.1 billion , or 16.8% of total loans in 2017 and 2016, respectively. There were no other concentrations of loans related to any single industry in excess of 10% of total loans at year-end 2017 or 2016. At year-end 2017, the Company had pledged loans totaling $350.7 million to the Federal Reserve Bank of Boston as collateral for certain borrowing arrangements. Also, residential first mortgage loans are subject to a blanket lien for FHLBB advances. See Note 12 - Borrowed Funds. At year-end 2017 and 2016, the Company’s commitments outstanding to related parties totaled $50.8 million and $38.7 million , respectively, and the loans outstanding against these commitments totaled $44.1 million and $25.6 million , respectively. Related parties include directors and executive officers of the Company and its subsidiaries, as well as their respective affiliates in which they have a controlling interest and immediate family members. For the years 2017 and 2016, all related party loans were performing. The carrying amount of the acquired loans at December 31, 2017 totaled $2.2 billion . A subset of these loans was determined to have evidence of credit deterioration at acquisition date, which is accounted for in accordance with ASC 310-30. These purchased credit-impaired loans presently maintain a carrying value of $97.3 million . These loans are evaluated for impairment through the quarterly reforecasting of expected cash flows. Of the $97.3 million , $53.3 million are Commercial Real Estate, $34.6 million are Commercial and Industrial loans, $7.0 million are Residential Mortgages, and $2.4 million are Consumer loans. The carrying amount of the acquired loans at December 31, 2016 totaled $1.3 billion . A subset of these loans was determined to have evidence of credit deterioration at acquisition date, which is accounted for in accordance with ASC 310-30. These purchased credit-impaired loans maintained a carrying value of $46.8 million . Of the $46.8 million , $34.8 million were Commercial Real Estate, $3.4 million were Commercial and Industrial loans, $7.3 million were Residential Mortgages, and $1.3 million were Consumer loans. The following table summarizes activity in the accretable yield for the acquired loan portfolio that falls under the purview of ASC 310-30, Loans and Debt Securities Acquired with Deteriorated Credit Quality : (In thousands) 2017 2016 2015 Balance at beginning of period $ 8,738 $ 6,925 $ 2,541 Acquisitions 10,815 6,125 4,777 Reclassification from nonaccretable difference for loans with improved cash flows (23 ) 2,488 3,640 Changes in expected cash flows that do not affect nonaccretable difference (2,380 ) (3,018 ) — Reclassification to TDR — (185 ) — Accretion (5,589 ) (3,597 ) (4,033 ) Balance at end of period $ 11,561 $ 8,738 $ 6,925 The following is a summary of past due loans at December 31, 2017 and 2016: Business Activities Loans (in thousands) 30-59 Days 60-89 Days >90 Days Past Due Total Past Current Total Loans Past Due > December 31, 2017 Commercial real estate: Construction $ — $ — $ — $ — $ 181,371 $ 181,371 $ — Single and multi-family — — 451 451 216,632 217,083 — Commercial real estate 1,925 48 5,023 6,996 1,812,257 1,819,253 457 Total 1,925 48 5,474 7,447 2,210,260 2,217,707 457 Commercial and industrial loans Total 4,031 1,912 6,023 11,966 1,170,603 1,182,569 128 Residential mortgages: 1-4 family 2,412 242 2,186 4,840 1,803,184 1,808,024 520 Construction — — — — 5,177 5,177 — Total 2,412 242 2,186 4,840 1,808,361 1,813,201 520 Consumer loans: Home equity 444 1,235 1,747 3,426 291,528 294,954 120 Auto and other 3,389 599 1,597 5,585 598,182 603,767 143 Total 3,833 1,834 3,344 9,011 889,710 898,721 263 Total $ 12,201 $ 4,036 $ 17,027 $ 33,264 $ 6,078,934 $ 6,112,198 $ 1,368 Business Activities Loans (in thousands) 30-59 Days 60-89 Days >90 Days Past Due Total Past Current Total Loans Past Due > December 31, 2016 Commercial real estate: Construction $ — $ — $ — $ — $ 253,302 $ 253,302 $ — Single and multi-family 618 110 624 1,352 190,467 191,819 155 Commercial real estate 481 2,243 4,212 6,936 1,474,287 1,481,223 — Total 1,099 2,353 4,836 8,288 1,918,056 1,926,344 155 Commercial and industrial loans Total 3,090 1,301 6,290 10,681 897,421 908,102 5 Residential mortgages: 1-4 family 1,393 701 4,179 6,273 1,577,521 1,583,794 1,956 Construction 10 — — 10 11,168 11,178 — Total 1,403 701 4,179 6,283 1,588,689 1,594,972 1,956 Consumer loans: Home equity 99 — 2,981 3,080 310,441 313,521 306 Auto and other 2,483 494 968 3,945 474,423 478,368 16 Total 2,582 494 3,949 7,025 784,864 791,889 322 Total $ 8,174 $ 4,849 $ 19,254 $ 32,277 $ 5,189,030 $ 5,221,307 $ 2,438 Acquired Loans (in thousands) 30-59 Days 60-89 Days >90 Days Past Due Total Past Acquired Total Loans Past Due > December 31, 2017 Commercial real estate: Construction $ — $ — $ — $ — $ 7,655 $ 84,965 $ — Single and multi-family 671 — 203 874 2,846 206,082 — Commercial real estate 816 1,875 2,156 4,847 42,801 755,988 109 Total 1,487 1,875 2,359 5,721 53,302 1,047,035 109 Commercial and industrial loans Total 1,252 268 1,439 2,959 34,629 621,370 23 Residential mortgages: 1-4 family 957 2,581 1,247 4,785 6,974 289,373 30 Construction — — — — — 233 — Total 957 2,581 1,247 4,785 6,974 289,606 30 Consumer loans: Home equity 286 40 1,965 2,291 1,956 115,227 — Auto and other 346 135 430 911 483 113,902 38 Total 632 175 2,395 3,202 2,439 229,129 38 Total $ 4,328 $ 4,899 $ 7,440 $ 16,667 $ 97,344 $ 2,187,140 $ 200 Acquired Loans (in thousands) 30-59 Days 60-89 Days >90 Days Past Due Total Past Acquired Total Loans Past Due > December 31, 2016 Commercial real estate: Construction $ — $ — $ — $ — $ 47 $ 34,207 $ — Single and multi-family 2 — 437 439 4,726 125,672 — Commercial real estate 1,555 — 765 2,320 30,047 530,215 — Total 1,557 — 1,202 2,759 34,820 690,094 — Commercial and industrial loans: Total 1,850 15 1,262 3,127 3,369 153,936 24 Residential mortgages: 1-4 family 321 343 2,015 2,679 7,283 297,355 443 Construction — — — — — 804 — Total 321 343 2,015 2,679 7,283 298,159 443 Consumer loans: Home equity 753 — 870 1,623 957 80,279 353 Auto and other 542 314 1,686 2,542 387 106,012 791 Total 1,295 314 2,556 4,165 1,344 186,291 1,144 Total $ 5,023 $ 672 $ 7,035 $ 12,730 $ 46,816 $ 1,328,480 $ 1,611 The following is summary information pertaining to non-accrual loans at year-end 2017 and 2016: December 31, 2017 December 31, 2016 (In thousands) Business Activities Acquired Loans (1) Total Business Activities Acquired Loans (2) Total Commercial real estate: Construction — — — — — — Single and multi-family 451 203 654 469 437 906 Other commercial real estate 4,566 2,047 6,613 4,212 765 4,977 Total 5,017 2,250 7,267 4,681 1,202 5,883 Commercial and industrial loans: Total 5,895 1,333 7,228 6,285 1,155 7,440 Residential mortgages: 1-4 family $ 1,666 $ 1,217 $ 2,883 $ 2,223 $ 1,572 $ 3,795 Construction — — — — — — Total 1,666 1,217 2,883 2,223 1,572 3,795 Consumer loans: Home equity 1,627 1,965 3,592 2,675 517 3,192 Auto and other 1,454 392 1,846 952 895 1,847 Total 3,081 2,357 5,438 3,627 1,412 5,039 Total non-accrual loans $ 15,659 $ 7,157 $ 22,816 $ 16,816 $ 5,341 $ 22,157 (1) At year-end 2017, acquired credit impaired loans account for $83 thousand of loans greater than 90 days past due that are not presented in the above table. (2) At year-end 2016, acquired credit impaired loans account for $83 thousand of loans greater than 90 days past due that are not presented in the above table. Loans evaluated for impairment as of December 31, 2017 and 2016 were as follows: Business Activities Loans (In thousands) Commercial Commercial Residential Consumer Total Loans receivable: Balance at end of year Individually evaluated for impairment $ 33,732 $ 5,761 $ 3,872 $ — $ 43,365 Collectively evaluated 2,183,975 1,176,808 1,809,329 898,721 6,068,833 Total $ 2,217,707 $ 1,182,569 $ 1,813,201 $ 898,721 $ 6,112,198 Business Activities Loans (In thousands) Commercial Commercial Residential Consumer Total Loans receivable: Balance at end of year Individually evaluated for impairment $ 25,549 $ 5,705 $ 2,775 $ 2,703 $ 36,732 Collectively evaluated 1,900,795 902,397 1,592,197 789,186 5,184,575 Total $ 1,926,344 $ 908,102 $ 1,594,972 $ 791,889 $ 5,221,307 Acquired Loans (In thousands) Commercial Commercial Residential Consumer Total Loans receivable: Balance at end of year Individually evaluated for impairment $ 4,244 $ 421 $ 2,617 $ 27 $ 7,309 Purchased credit-impaired loans 53,302 34,629 6,974 2,439 97,344 Collectively evaluated 989,489 586,320 280,015 226,663 2,082,487 Total $ 1,047,035 $ 621,370 $ 289,606 $ 229,129 $ 2,187,140 Acquired Loans (In thousands) Commercial Commercial Residential Consumer Total Loans receivable: Balance at end of year Individually evaluated for impairment $ 4,256 $ 635 $ 308 $ 406 $ 5,605 Purchased credit-impaired loans 34,820 3,369 7,283 1,344 46,816 Collectively evaluated 651,018 149,932 290,568 184,541 1,276,059 Total $ 690,094 $ 153,936 $ 298,159 $ 186,291 $ 1,328,480 The following is a summary of impaired loans at year-end 2017 and 2016 and for the years then ended: Business Activities Loans At December 31, 2017 (In thousands) Recorded Investment (1) Unpaid Principal Related Allowance With no related allowance: Commercial real estate - construction $ — $ — $ — Commercial real estate - single and multifamily 1,077 3,607 — Other commercial real estate 18,285 18,611 — Other commercial and industrial loans 2,060 2,629 — Residential mortgages - 1-4 family 660 1,075 — Consumer - home equity 867 1,504 — With an allowance recorded: Commercial real estate - construction $ 159 $ 159 $ 1 Commercial real estate - single and multifamily 159 171 1 Other commercial real estate 14,321 15,235 227 Other commercial and industrial loans 3,716 4,249 66 Residential mortgages - 1-4 family 1,344 1,446 130 Consumer - home equity 1,014 999 34 Consumer - other 17 17 1 Total Commercial real estate $ 34,001 $ 37,783 $ 229 Commercial and industrial 5,776 6,878 66 Residential mortgages 2,004 2,521 130 Consumer 1,898 2,520 35 Total impaired loans $ 43,679 $ 49,702 $ 460 (1) The Recorded Investment represents the face amount of the loan increased or decreased by applicable accrued interest, net deferred loan fees and costs, and unamortized premium or discount, and reflects direct charge-offs. This amount is a component of total loans on the Consolidated Balance Sheet. (2) The Unpaid Principal Balance represents the customer's legal obligation to the Company. Business Activities Loans At December 31, 2016 (In thousands) Recorded Investment (1) Unpaid Principal Related Allowance With no related allowance: Other commercial real estate $ 18,905 $ 18,905 $ — Other commercial and industrial loans 382 382 — Residential mortgages - 1-4 family 2,101 2,101 — Consumer - home equity 1,605 1,605 — With an allowance recorded: Commercial real estate - single and multifamily $ 179 $ 181 $ 2 Other commercial real estate 6,306 6,462 156 Other commercial and industrial loans 5,060 5,324 264 Residential mortgages - 1-4 family 538 674 136 Consumer - home equity 942 1,098 156 Total Commercial real estate $ 25,390 $ 25,548 $ 158 Commercial and industrial 5,442 5,706 264 Residential mortgages 2,639 2,775 136 Consumer 2,547 2,703 156 Total impaired loans $ 36,018 $ 36,732 $ 714 (1) The Recorded Investment represents the face amount of the loan increased or decreased by applicable accrued interest, net deferred loan fees and costs, and unamortized premium or discount, and reflects direct charge-offs. This amount is a component of total loans on the Consolidated Balance Sheet. (2) The Unpaid Principal Balance represents the customer's legal obligation to the Company. Acquired Loans At December 31, 2017 (In thousands) Recorded Investment (1) Unpaid Principal Related Allowance With no related allowance: Commercial real estate - single and multifamily $ 204 $ 290 $ — Other commercial real estate loans 1,123 2,794 — Other commercial and industrial loans 255 310 — Residential mortgages - 1-4 family 658 671 — Consumer - home equity 1,374 1,654 — Consumer - other 27 27 — With an allowance recorded: Commercial real estate - single and multifamily $ 887 $ 880 $ 18 Other commercial real estate loans 2,043 1,661 38 Other commercial and industrial loans 165 166 1 Residential mortgages - 1-4 family 166 185 9 Consumer - home equity 433 540 45 Total Commercial real estate $ 4,257 $ 5,625 $ 56 Commercial and industrial 420 476 1 Residential mortgages 824 856 9 Consumer 1,834 2,221 45 Total impaired loans $ 7,335 $ 9,178 $ 111 (1) The Recorded Investment represents the face amount of the loan increased or decreased by applicable accrued interest, net deferred loan fees and costs, and unamortized premium or discount, and reflects direct charge-offs. This amount is a component of total loans on the Consolidated Balance Sheet. (2) The Unpaid Principal Balance represents the customer's legal obligation to the Company. Acquired Loans December 31, 2016 (In thousands) Recorded Investment (1) Unpaid Principal Related Allowance With no related allowance: Other commercial real estate loans $ 547 $ 547 $ — Residential mortgages - 1-4 family 208 208 — Consumer - home equity — — — Consumer - other — — — With an allowance recorded: Commercial real estate - single and multifamily $ 1,250 $ 1,358 $ 108 Other commercial real estate loans 2,209 2,351 142 Other Commercial and industrial loans 576 635 59 Residential mortgages - 1-4 family 89 100 11 Consumer - home equity 292 406 114 Total Commercial real estate $ 4,006 $ 4,256 $ 250 Commercial and industrial 576 635 59 Residential mortgages 297 308 11 Consumer 292 406 114 Total impaired loans $ 5,171 $ 5,605 $ 434 (1) The Recorded Investment represents the face amount of the loan increased or decreased by applicable accrued interest, net deferred loan fees and costs, and unamortized premium or discount, and reflects direct charge-offs. This amount is a component of total loans on the Consolidated Balance Sheet. (2) The Unpaid Principal Balance represents the customer's legal obligation to the Company. The following is a summary of the average recorded investment and interest income recognized on impaired loans as of December 31, 2017, 2016 and 2015: Business Activities Loans December 31, 2017 December 31, 2016 December 31, 2015 (in thousands) Average Recorded Cash Basis Interest Average Recorded Cash Basis Interest Average Recorded Cash Basis Interest With no related allowance: Commercial real estate - construction $ — $ — $ — $ — $ 2,245 $ 92 Commercial real estate - single and multifamily 341 214 36 1 60 — Other commercial real estate 20,867 1,123 6,463 1,155 12,487 302 Other commercial and industrial 4,437 265 3,349 131 3,870 177 Residential mortgages - 1-4 family 1,128 31 2,403 91 1,353 38 Consumer-home equity 1,291 30 612 5 442 13 Consumer-other 72 3 2 — — — With an allowance recorded: Commercial mortgages - construction $ 41 $ 3 $ — $ — $ — $ — Commercial real estate - single and multifamily 169 12 15 6 — — Other commercial real estate 11,372 520 7,576 349 3,214 132 Other commercial and industrial 3,251 267 2,002 225 810 37 Residential mortgages - 1-4 family 1,289 59 682 26 1,704 72 Consumer-home equity 1,007 29 999 35 83 — Consumer - other 4 1 103 4 112 4 Total Commercial real estate $ 32,790 $ 1,872 $ 14,090 $ 1,511 $ 18,006 $ 526 Commercial and industrial 7,688 532 5,351 356 4,680 214 Residential mortgages 2,417 90 3,085 117 3,057 110 Consumer loans 2,374 63 1,716 44 637 17 Total impaired loans $ 45,269 $ 2,557 $ 24,242 $ 2,028 $ 26,380 $ 867 Acquired Loans December 31, 2017 December 31, 2016 December 31, 2015 (in thousands) Average Recorded Cash Basis Interest Average Recorded Cash Basis Interest Average Recorded Cash Basis Interest With no related allowance: Commercial real estate - construction $ — $ — $ — $ — $ 445 $ 60 Commercial real estate - single and multifamily 342 82 — — 2,014 57 Other commercial real estate 487 239 521 20 1,721 37 Other commercial and industrial 581 43 492 9 — — Residential mortgages - 1-4 family 390 28 293 12 463 6 Consumer - home equity 773 22 — — 152 5 Consumer - other 7 1 105 1 59 5 With an allowance recorded: Commercial real estate - construction $ — $ — $ — $ — $ — $ — Commercial real estate - single and multifamily 903 47 1,064 115 623 33 Other commercial real estate 1,719 91 2,618 165 1,384 96 Other commercial and industrial 47 13 369 17 31 3 Residential mortgages - 1-4 family 173 9 214 25 304 9 Consumer - home equity 400 21 — — 195 7 Total Commercial real estate $ 3,451 $ 459 $ 4,203 $ 300 $ 6,187 $ 283 Commercial and industrial 628 56 861 26 31 3 Residential mortgages 563 37 507 37 767 15 Consumer loans 1,180 44 105 1 406 17 Total impaired loans $ 5,822 $ 596 $ 5,676 $ 364 $ 7,391 $ 318 No additional funds are committed to be advanced in connection with impaired loans. Troubled Debt Restructuring Loans The Company’s loan portfolio also includes certain loans that have been modified in a Troubled Debt Restructuring (TDR), where economic concessions have been granted to borrowers who have experienced or are expected to experience financial difficulties. These concessions typically result from the Company’s loss mitigation activities and could include reductions in the interest rate, payment extensions, forgiveness of principal, forbearance, or other actions. Certain TDRs are classified as nonperforming at the time of restructure and may only be returned to performing status after considering the borrower’s sustained repayment performance for a reasonable period, generally six months . TDRs are evaluated individually for impairment and may result in a specific allowance amount allocated to an individual loan. The following tables include the recorded investment and number of modifications for modified loans identified during the years-ended December 31, 2017, 2016, and 2015 respectively. The tables include the recorded investment in the loans prior to a modification and also the recorded investment in the loans after the loans were restructured. The modifications for the year-ended December 31, 2017 were attributable to interest rate concessions, principal concessions, maturity date extensions, modified payment terms, reamortization, and accelerated maturity. The modifications for the year-ended December 31, 2016 were attributable to interest rate concessions, maturity date extensions, modified payment terms, reamortization, and accelerated maturity. Modifications by Class Number of Pre-Modification Post-Modification Troubled Debt Restructurings Commercial - Single and multifamily 1 $ 235 $ 235 Commercial - Other 15 13,445 11,718 Commercial and industrial - Other 12 3,507 3,507 Residential - 1-4 Family 4 331 314 Consumer - Home Equity 3 122 122 35 $ 17,640 $ 15,896 Modifications by Class Number of Pre-Modification Post-Modification Troubled Debt Restructurings Commercial - Single and multifamily 5 $ 437 $ 437 Commercial - Other 5 16,651 16,651 Commercial and industrial - Other 4 555 555 Residential - 1-4 Family 2 5 5 Consumer - Home Equity 1 117 117 17 $ 17,765 $ 17,765 Modifications by Class Number of Pre-Modification Post-Modification Troubled Debt Restructurings Commercial - Construction 1 $ 123 $ 123 Commercial - Single and multifamily 2 307 307 Commercial - Other 4 8,577 7,274 Commercial and industrial - Other 6 9,041 8,904 Consumer - Other 1 999 999 14 $ 19,047 $ 17,607 The following tables disclose the recorded investment and number of modifications for TDRs for the prior years where a concession was made and the borrower subsequently defaulted in the respective reporting period. For the year ended 2017, there were three loans that were restructured that had subsequently defaulted during the period. For the period ended 2016, there were no loans that were restructured that had subsequently defaulted during the period. For the year ended 2015, there were eight loans that were restructured that had subsequently defaulted during the period. Modifications that subsequently defaulted for the twelve months ending December 31, 2017 Number of Contracts Recorded Investment Troubled Debt Restructurings Commercial - Single and multifamily — $ — Commercial - Other 1 113 Commercial and industrial - Other 2 492 Residential - 1-4 Family — — 3 $ 605 Modifications that subsequently defaulted for the twelve months ending December 31, 2015 Number of Contracts Recorded Investment Troubled Debt Restructurings Commercial - Single and multifamily 1 $ — Commercial - Other 1 373 Commercial and industrial - Other 4 6,579 Residential - 1-4 Family 2 169 8 $ 7,121 The following table presents the Company’s TDR activity in 2017 and 2016: (In thousands) 2017 2016 2015 Balance at beginning of year $ 33,829 $ 22,048 $ 16,714 Principal payments (3,213 ) (5,870 ) (5,460 ) TDR status change (1) — 2,235 — Other reductions (2) (4,522 ) (2,349 ) (3,160 ) Newly identified TDRs 15,896 17,765 13,954 Balance at end of year $ 41,990 $ 33,829 $ 22,048 ________________________________ (1) TDR status change classification represents TDR loans with a specified interest rate equal to or greater than the rate that the Company was willing to accept at the time of the restructuring for a new loan with comparable risk and the loan was on current payment status and not impaired based on the terms specified by the restructuring agreement. (2) Other reductions classification consists of transfer to other real estate owned, charge-offs to loans, and other loan sale payoffs. The evaluation of certain loans individually for specific impairment includes loans that were previously classified as TDRs or continue to be classified as TDRs. As of December 31, 2017, the Company maintained no foreclosed residential real estate property. Additionally, residential mortgage loans collateralized by real estate property that are in the process of foreclosure as of December 31, 2017 and December 31, 2016 totaled $4.9 million and $4.8 million , respectively. As of December 31, 2016, foreclosed residential real estate property totaled $151 thousand .

LOAN LOSS ALLOWANCE

LOAN LOSS ALLOWANCE	12 Months Ended
	Dec. 31, 2017
Receivables [Abstract]
LOAN LOSS ALLOWANCE	LOAN LOSS ALLOWANCE Activity in the allowance for loan losses for 2017, 2016, and 2015 was as follows: Business Activities Loans (In thousands) Commercial Commercial Residential Consumer Total Balance at beginning of year $ 16,498 $ 9,447 $ 7,805 $ 5,479 $ 39,229 Charged-off loans 3,875 3,373 806 3,470 11,524 Recoveries on charged-off loans 170 179 270 270 889 Provision for loan losses 4,050 7,597 2,151 3,528 17,326 Balance at end of year $ 16,843 $ 13,850 $ 9,420 $ 5,807 $ 45,920 Individually evaluated for impairment 229 66 130 35 460 Collectively evaluated 16,614 13,784 9,290 5,772 45,460 Total $ 16,843 $ 13,850 $ 9,420 $ 5,807 $ 45,920 Business Activities Loans (In thousands) Commercial real estate Commercial Residential Consumer Total Balance at beginning of year $ 14,591 $ 7,385 $ 7,613 $ 4,985 $ 34,574 Charged-off loans 2,127 4,620 2,036 1,722 10,505 Recoveries on charged-off loans 243 123 159 267 792 Provision for loan losses 3,791 6,559 2,069 1,949 14,368 Balance at end of year $ 16,498 $ 9,447 $ 7,805 $ 5,479 $ 39,229 Individually evaluated for impairment 158 264 136 156 714 Collectively evaluated 16,340 9,183 7,669 5,323 38,515 Total $ 16,498 $ 9,447 $ 7,805 $ 5,479 $ 39,229 Business Activities Loans (In thousands) Commercial Commercial Residential Consumer Total Balance at beginning of year $ 14,740 $ 5,246 $ 6,864 $ 5,945 $ 32,795 Charged-off loans 6,865 2,358 1,215 1,183 11,621 Recoveries on charged-off loans 164 169 141 285 759 Provision for loan losses 6,552 4,328 1,823 (62 ) 12,641 Balance at end of year $ 14,591 $ 7,385 $ 7,613 $ 4,985 $ 34,574 Individually evaluated for impairment 149 21 153 103 426 Collectively evaluated 14,442 7,364 7,460 4,882 34,148 Total $ 14,591 $ 7,385 $ 7,613 $ 4,985 $ 34,574 Acquired Loans (In thousands) Commercial Commercial Residential Consumer Total Balance at beginning of year $ 2,303 $ 1,164 $ 766 $ 536 $ 4,769 Charged-off loans 771 844 797 648 3,060 Recoveries on charged-off loans 65 245 43 153 506 Provision for loan losses 2,259 560 586 294 3,699 Balance at end of year $ 3,856 $ 1,125 $ 598 $ 335 $ 5,914 Individually evaluated for impairment 56 1 9 45 111 Collectively evaluated 3,800 1,124 589 290 5,803 Total $ 3,856 $ 1,125 $ 598 $ 335 $ 5,914 Acquired Loans (In thousands) Commercial Commercial Residential Consumer Total Balance at beginning of year $ 1,903 $ 1,330 $ 976 $ 525 $ 4,734 Charged-off loans 977 1,095 829 620 3,521 Recoveries on charged-off loans 61 266 144 91 562 Provision for loan losses 1,316 663 475 540 2,994 Balance at end of year $ 2,303 $ 1,164 $ 766 $ 536 $ 4,769 Individually evaluated for impairment 250 59 11 114 434 Collectively evaluated 2,053 1,105 755 422 4,335 Total $ 2,303 $ 1,164 $ 766 $ 536 $ 4,769 Acquired Loans (In thousands) Commercial Commercial Residential Consumer Total Balance at beginning of year $ 790 $ 1,093 $ 615 $ 369 $ 2,867 Charged-off loans 681 752 642 992 3,067 Recoveries on charged-off loans 418 289 64 78 849 Provision for loan losses 1,376 700 939 1,070 4,085 Balance at end of year $ 1,903 $ 1,330 $ 976 $ 525 $ 4,734 Individually evaluated for impairment 43 — 30 25 98 Purchased credit-impaired loans 42 — — — 42 Collectively evaluated 1,818 1,330 946 500 4,594 Total $ 1,903 $ 1,330 $ 976 $ 525 $ 4,734 Credit Quality Information Business Activities Loans Credit Quality Analysis The Company monitors the credit quality of its portfolio by using internal risk ratings that are based on regulatory guidance. Loans that are given a Pass rating are not considered a problem credit. Loans that are classified as Special Mention loans are considered to have potential weaknesses and are evaluated closely by management. Substandard and non-accruing loans are loans for which a definitive weakness has been identified and which may make full collection of contractual cash flows questionable. Doubtful loans are those with identified weaknesses that make full collection of contractual cash flows, on the basis of currently existing facts, conditions, and values, highly questionable and improbable. For commercial credits, the Company assigns an internal risk rating at origination and reviews the rating annual, semiannually, or quarterly depending on the risk rating. The rating is also reassessed at any point in time when management becomes aware of information that may affect the borrower’s ability to fulfill their obligations. The Company risk rates its residential mortgages, including 1-4 family and residential construction loans, based on a three rating system: Pass, Special Mention, and Substandard. Loans that are current within 59 days are rated Pass. Residential mortgages that are 60 - 89 days delinquent are rated Special Mention. Loans delinquent for 90 days or greater are rated Substandard and generally placed on non-accrual status. Home equity loans are risk rated based on the same rating system as the Company’s residential mortgages. Ratings for other consumer loans, including auto loans, are based on a two rating system. Loans that are current within 119 days are rated Performing while loans delinquent for 120 days or more are rated Non-performing. Other consumer loans are placed on non-accrual at such time as they become Non-performing. Acquired Loans Credit Quality Analysis Upon acquiring a loan portfolio, our internal loan review function assigns risk ratings to the acquired loans, utilizing the same methodology as it does with business activities loans. This may differ from the risk rating policy of the predecessor bank. Loans which are rated Substandard or worse according to the rating process outlined below are deemed to be credit impaired loans accounted for under ASC 310-30, regardless of whether they are classified as performing or non-performing. The Bank utilizes a loan risk rating system for acquired loans consistent with loans originated from business activities, as outlined in the Credit Quality Information section of this Note. The ratings system is similar to loans originated through business activities. The Company presented several tables within this footnote separately for business activity loans and acquired loans in order to distinguish the credit performance of the acquired loans from the business activity loans. The following tables present the Company’s loans by risk rating at year-end 2017 and 2016: Business Activities Loans Commercial Real Estate Credit Risk Profile by Creditworthiness Category Construction Single and multi-family Real Estate Total commercial real estate (In thousands) 2017 2016 2017 2016 2017 2016 2017 2016 Grade: Pass $ 181,371 $ 253,302 $ 214,289 $ 189,310 $ 1,775,091 $ 1,434,762 $ 2,170,751 $ 1,877,374 Special mention — — 504 334 12,999 5,827 13,503 6,161 Substandard — — 2,290 2,175 31,163 40,598 33,453 42,773 Doubtful — — — — — 36 — 36 Total $ 181,371 $ 253,302 $ 217,083 $ 191,819 $ 1,819,253 $ 1,481,223 $ 2,217,707 $ 1,926,344 Commercial and Industrial Loans Credit Risk Profile by Creditworthiness Category Total comm. and industrial (In thousands) 2017 2016 Grade: Pass $ 1,156,240 $ 890,974 Special mention 12,806 123 Substandard 11,123 13,825 Doubtful 2,400 3,180 Total $ 1,182,569 $ 908,102 Residential Mortgages Credit Risk Profile by Internally Assigned Grade 1-4 family Construction Total residential mortgages (In thousands) 2017 2016 2017 2016 2017 2016 Grade: Pass $ 1,805,596 $ 1,578,913 $ 5,177 $ 11,178 $ 1,810,773 $ 1,590,091 Special mention 242 701 — — 242 701 Substandard 2,186 4,179 — — 2,186 4,179 Total $ 1,808,024 $ 1,583,793 $ 5,177 $ 11,178 $ 1,813,201 $ 1,594,971 Consumer Loans Credit Risk Profile Based on Payment Activity Home equity Auto and other Total consumer (In thousands) 2017 2016 2017 2016 2017 2016 Performing $ 293,327 $ 310,846 $ 602,313 $ 477,416 $ 895,640 $ 788,262 Nonperforming 1,627 2,675 1,454 952 3,081 3,627 Total $ 294,954 $ 313,521 $ 603,767 $ 478,368 $ 898,721 $ 791,889 Acquired Loans Commercial Real Estate Credit Risk Profile by Creditworthiness Category Construction Single and multi-family Real Estate Total commercial real estate (In thousands) 2017 2016 2017 2016 2017 2016 2017 2016 Grade: Pass $ 76,611 $ 33,461 $ 203,624 $ 119,414 $ 684,846 $ 496,562 $ 965,081 $ 649,437 Special mention — — 603 907 22,070 1,622 22,673 2,529 Substandard 8,354 746 1,855 5,351 49,072 32,031 59,281 38,128 Total $ 84,965 $ 34,207 $ 206,082 $ 125,672 $ 755,988 $ 530,215 $ 1,047,035 $ 690,094 Commercial and Industrial Loans Credit Risk Profile by Creditworthiness Category Total comm. and industrial (In thousands) 2017 2016 Grade: Pass $ 606,922 $ 147,102 Special mention 1,241 1,260 Substandard 13,207 5,574 Total $ 621,370 $ 153,936 Residential Mortgages Credit Risk Profile by Internally Assigned Grade 1-4 family Construction Total residential mortgages (In thousands) 2017 2016 2017 2016 2017 2016 Grade: Pass $ 281,160 $ 294,983 $ 233 $ 804 $ 281,393 $ 295,787 Special mention 2,704 343 — — 2,704 343 Substandard 5,509 2,029 — — 5,509 2,029 Total $ 289,373 $ 297,355 $ 233 $ 804 $ 289,606 $ 298,159 Consumer Loans Credit Risk Profile Based on Payment Activity Home equity Auto and other Total consumer (In thousands) 2017 2016 2017 2016 2017 2016 Performing $ 113,262 $ 79,762 $ 113,510 $ 105,117 $ 226,772 $ 184,879 Nonperforming 1,965 517 392 895 2,357 1,412 Total $ 115,227 $ 80,279 $ 113,902 $ 106,012 $ 229,129 $ 186,291 The following table summarizes information about total loans rated Special Mention or lower. The table below includes consumer loans that are Special Mention and Substandard accruing that are classified in the above table as performing based on payment activity. December 31, 2017 December 31, 2016 (In thousands) Business Acquired Loans Total Business Acquired Loans Total Non-Accrual $ 15,659 $ 7,240 $ 22,899 $ 16,816 $ 5,424 $ 22,240 Substandard Accruing 36,846 73,412 110,258 51,125 44,177 95,302 Total Classified 52,505 80,652 133,157 67,941 49,601 117,542 Special Mention 28,387 26,802 55,189 7,479 4,323 11,802 Total Criticized $ 80,892 $ 107,454 $ 188,346 $ 75,420 $ 53,924 $ 129,344

PREMISES AND EQUIPMENT

PREMISES AND EQUIPMENT	12 Months Ended
	Dec. 31, 2017
Property, Plant and Equipment [Abstract]
PREMISES AND EQUIPMENT	PREMISES AND EQUIPMENT Year-end premises and equipment are summarized as follows: (In thousands) 2017 2016 Estimated Useful Land $ 14,177 $ 10,563 N/A Buildings and improvements 99,821 85,319 5 - 39 years Furniture and equipment 49,600 42,693 3 - 7 years Construction in process 5,177 4,084 Premises and equipment, gross 168,775 142,659 Accumulated depreciation and amortization (59,423 ) (49,444 ) Premises and equipment, net $ 109,352 $ 93,215 Depreciation and amortization expense for the years 2017, 2016, and 2015 amounted to $9.9 million , $8.4 million , and $8.6 million , respectively.

GOODWILL AND OTHER INTANGIBLES

GOODWILL AND OTHER INTANGIBLES	12 Months Ended
	Dec. 31, 2017
Goodwill and Intangible Assets Disclosure [Abstract]
GOODWILL AND OTHER INTANGIBLES	GOODWILL AND OTHER INTANGIBLES Goodwill and other intangible assets are presented in the tables below. The Company completed one acquisition during 2017 which resulted in the capitalization of goodwill and other intangibles. In accordance with applicable accounting guidance, the Company allocated the amount paid to the fair value of the net assets acquired, with any excess amounts recorded as goodwill. There were three acquisitions during 2016. The goodwill balance is allocated to the consolidated Company. The activity impacting goodwill in 2017 and 2016 is as follows: (In thousands) 2017 2016 Balance, beginning of the period $ 403,106 $ 323,943 Goodwill acquired and adjusted: Commerce Bank 116,181 — 44 Business Capital — 15,892 Ronald N. Lazzaro, PC — 5,492 First Choice Bank — 58,036 Adjustments (1) — (257 ) Balance, end of the period $ 519,287 $ 403,106 ______________________________________________________________________________________________________ (1) In 2016, goodwill related to the Hampden and Firestone acquisitions was adjusted since acquisition dates to reflect new information available during the one-year measurement period. The Company tests goodwill impairment annually as of September 30, 2017 using third quarter data. The results of the qualitative assessment indicated it is more likely than not that the reporting unit's fair value exceeds its carrying amount, and accordingly, the two-step impairment test was not performed. If events or changes in circumstances indicate that impairment is possible, the Company will perform additional reviews. No impairment was recorded on goodwill for 2017, 2016 and 2015. The components of other intangible assets are as follows: (In thousands) Gross Intangible Assets Accumulated Amortization Net Intangible Assets December 31, 2017 Non-maturity deposits (core deposit intangible) $ 66,923 $ (33,024 ) $ 33,899 Insurance contracts 7,558 (7,526 ) 32 All other intangible assets 7,810 (3,445 ) 4,365 Total $ 82,291 $ (43,995 ) $ 38,296 December 31, 2016 Non-maturity deposits (core deposit intangible) $ 44,523 $ (30,099 ) $ 14,424 Insurance contracts 7,558 (7,504 ) 54 All other intangible assets 7,866 (2,899 ) 4,967 Total $ 59,947 $ (40,502 ) $ 19,445 Other intangible assets are amortized on a straight-line or accelerated basis over their estimated lives, which range from four to fifteen years. Amortization expense related to intangibles totaled $3.5 million in 2017, $2.9 million in 2016, and $3.6 million in 2015. The estimated aggregate future amortization expense for intangible assets remaining at year-end 2017 is as follows: 2018- $4.9 million ; 2019- $4.7 million ; 2020- $4.4 million ; 2021- $4.2 million ; 2022- $ 4.1 million ; and thereafter- $16.0 million . For the years 2017, 2016, and 2015, no impairment charges were identified for the Company’s intangible assets.

OTHER ASSETS

OTHER ASSETS	12 Months Ended
	Dec. 31, 2017
Other Assets [Abstract]
OTHER ASSETS	OTHER ASSETS Year-end other assets are summarized as follows: (In thousands) 2017 2016 Capitalized servicing rights $ 16,361 $ 11,524 Accrued interest receivable 33,739 26,113 Accrued federal and state tax receivable (1) 33,101 19,076 Derivative assets 19,308 21,617 Assets held for sale 1,392 — Other 13,182 20,127 Total other assets $ 117,083 $ 98,457 (1) Accrued federal and state tax receivable as of December 31, 2017 includes $4.3 million of New York State refundable tax credits from investment in historical tax credit partnerships in New York State. This balance was $5.9 million at year-end 2016. The Bank sells loans in the secondary market and retains the ability to service many of these loans. The Bank earns fees for the servicing provided. Loans sold and serviced for others amounted to $1.8 billion , $1.3 billion , and $0.8 billion at year-end 2017, 2016, and 2015, respectively. Loans serviced for others are not included in the accompanying consolidated balance sheets. The risks inherent in servicing assets relate primarily to changes in prepayments that result from shifts in interest rates. Contractually specified servicing fees were $4.6 million , $3.2 million , and $1.7 million for the years 2017, 2016, and 2015, respectively, and included as a component of loan related fees within non-interest income. The significant assumptions used in the valuation at year-end 2017 included a weighted average discount rate of 10.4% and pre-payment speed assumptions ranging from 7.78% to 12.78% . Servicing rights activity was as follows: (In thousands) 2017 2016 Balance at beginning of year $ 11,524 $ 5,187 Acquired from 44 Business Capital — 3,489 Acquired from First Choice Bank (1) — 696 Additions 7,604 4,116 Amortization (2,446 ) (1,964 ) Change in fair value (221 ) — Allowance adjustment (100 ) — Balance at end of year $ 16,361 $ 11,524 (1) Amounts acquired from First Choice Bank are accounted for at fair value. The balance as of December 31, 2017 and December 31, 2016 were $3.8 million and $0.8 million , respectively.

DEPOSITS

DEPOSITS	12 Months Ended
	Dec. 31, 2017
Deposits [Abstract]
DEPOSITS	DEPOSITS A summary of year-end time deposits is as follows: (In thousands) 2017 2016 Maturity date: Within 1 year $ 1,790,056 $ 1,316,973 Over 1 year to 2 years 546,381 582,764 Over 2 years to 3 years 268,897 142,160 Over 3 years to 4 years 161,314 150,388 Over 4 years to 5 years 121,400 137,845 Over 5 years 2,157 3,413 Total $ 2,890,205 $ 2,333,543 Account balances: Less than $100,000 $ 733,785 $ 656,055 $100,000 or more 2,156,420 1,677,488 Total $ 2,890,205 $ 2,333,543 Included in total deposits are brokered deposits of $1.2 billion and $0.9 billion at December 31, 2017 and December 31, 2016, respectively. Included in total brokered deposits are reciprocal deposits of $99.8 million and $113.4 million at December 31, 2017 and December 31, 2016, respectively. Included in total deposits are related party deposits of $36.0 million and $17.2 million at December 31, 2017 and December 31, 2016, respectively.

BORROWED FUNDS

BORROWED FUNDS	12 Months Ended
	Dec. 31, 2017
Debt Disclosure [Abstract]
BORROWED FUNDS	BORROWED FUNDS Borrowed funds at December 31, 2017 and 2016 are summarized, as follows: 2017 2016 (in thousands, except rates) Principal Weighted Principal Weighted Short-term borrowings: Advances from the FHLBB $ 667,300 1.48 % $ 1,072,044 0.71 % Other Borrowings — — 10,000 2.42 Total short-term borrowings: 667,300 1.48 1,082,044 0.72 Long-term borrowings: Advances from the FHLBB 380,436 1.54 142,792 1.53 Subordinated notes 73,875 7.00 73,697 7.00 Junior subordinated notes 15,464 3.30 15,464 2.77 Total long-term borrowings: 469,775 2.46 231,953 3.35 Total $ 1,137,075 1.88 % $ 1,313,997 1.19 % Short-term debt includes Federal Home Loan Bank of Boston (“FHLBB”) advances with an original maturity of less than one year. At year-end 2017, the Company maintained a short-term line-of-credit drawdown through a correspondent bank. The Bank also maintains a $3.0 million secured line of credit with the FHLBB that bears a daily adjustable rate calculated by the FHLBB. There was no outstanding balance on the FHLBB line of credit for the periods ended December 31, 2017 and December 31, 2016. The Company is in compliance with all debt covenants as of December 31, 2017. The Bank is approved to borrow on a short-term basis from the Federal Reserve Bank of Boston as a non-member bank. The Bank has pledged certain loans and securities to the Federal Reserve Bank to support this arrangement. No borrowings with the Federal Reserve Bank of Boston took place for the periods ended December 31, 2017 and December 31, 2016. Long-term FHLBB advances consist of advances with an original maturity of more than one year. The advances outstanding at December 31, 2017 include amortizing advances totaling $1.4 million . The advances outstanding at December 31, 2016 include callable advances totaling $11.0 million , and amortizing advances totaling $1.2 million . All FHLBB borrowings, including the line of credit, are secured by a blanket security agreement on certain qualified collateral, principally all residential first mortgage loans and certain securities. A summary of maturities of FHLBB advances at year-end 2017 is as follows: 2017 (In thousands) Amount Weighted Fixed rate advances maturing: 2018 $ 836,115 1.43 % 2019 150,082 1.64 2020 54,101 2.04 2021 220 3.21 2022 and beyond 7,218 2.64 Total fixed rate advances $ 1,047,736 1.50 Total FHLBB advances $ 1,047,736 1.50 % The Company did not have variable-rate FHLB advances for the period ended December 31, 2017 and December 31, 2016. In September 2012, the Company issued fifteen year subordinated notes in the amount of $75.0 million at a discount of 1.15% . The interest rate is fixed at 6.875% for the first ten years. After ten years, the notes become callable and convert to an interest rate of three month LIBOR plus 5.113% . The subordinated note includes reduction to the note principal balance of $583 thousand and $706 thousand for unamortized debt issuance costs as of December 31, 2017 and December 31 2016, respectively. The Company holds 100% of the common stock of Berkshire Hills Capital Trust I (“Trust I”) which is included in other assets with a cost of $0.5 million . The sole asset of Trust I is $15.5 million of the Company’s junior subordinated debentures due in 2035. These debentures bear interest at a variable rate equal to LIBOR plus 1.85% and had a rate of 3.30% and 2.77% at December 31, 2017 and December 31, 2016, respectively. The Company has the right to defer payments of interest for up to five years on the debentures at any time, or from time to time, with certain limitations, including a restriction on the payment of dividends to shareholders while such interest payments on the debentures have been deferred. The Company has not exercised this right to defer payments. The Company has the right to redeem the debentures at par value on each quarterly payment date. Trust I is considered a variable interest entity for which the Company is not the primary beneficiary. Accordingly, Trust I is not consolidated into the Company’s financial statements.

OTHER LIABILITIES

OTHER LIABILITIES	12 Months Ended
	Dec. 31, 2017
Other Liabilities Disclosure [Abstract]
OTHER LIABILITIES	OTHER LIABILITIES Year-end other liabilities are summarized as follows: December 31, (In thousands) 2017 2016 Derivative liabilities $ 15,838 $ 24,420 Capital lease obligation 11,323 11,639 Asset purchase settlement payable 70,637 29,158 Employee benefits liability 27,093 17,972 Level lease liability 5,766 6,997 Accrued interest payable 6,813 4,394 Customer transaction clearing accounts 9,118 1,786 Other 41,294 36,789 Total other liabilities $ 187,882 $ 133,155

EMPLOYEE BENEFIT PLANS

EMPLOYEE BENEFIT PLANS	12 Months Ended
	Dec. 31, 2017
Retirement Benefits [Abstract]
EMPLOYEE BENEFIT PLANS	EMPLOYEE BENEFIT PLANS Pension Plan The Company maintains a legacy, employer-sponsored defined benefit pension plan (the “Plan”) for which participation and benefit accruals were frozen on January 1, 2003. The Plan was assumed in connection with the Rome Bancorp acquisition in 2011. Accordingly, no employees are permitted to commence participation in the Plan and future salary increases and years of credited service are not considered when computing an employee’s benefits under the Plan. As of December 31, 2017, all minimum Employee Retirement Income Security Act (“ERISA”) funding requirements have been met. Information regarding the pension plan is as follows: December 31, (In thousands) 2017 2016 Change in projected benefit obligation: Projected benefit obligation at beginning of year $ 6,126 $ 6,585 Service Cost 66 76 Interest cost 237 267 Actuarial gain 309 (308 ) Benefits paid (324 ) (318 ) Settlements (61 ) (176 ) Projected benefit obligation at end of year 6,353 6,126 Accumulated benefit obligation 6,353 6,126 Change in fair value of plan assets: Fair value of plan assets at plan beginning of year 5,121 5,211 Actual return on plan assets 710 404 Benefits paid (324 ) (318 ) Settlements (61 ) (176 ) Fair value of plan assets at end of year 5,446 5,121 Underfunded status $ 907 $ 1,005 Amounts Recognized in Consolidated Balance Sheet Other Liabilities $ 907 $ 1,005 Net periodic pension cost is comprised of the following: December 31, (In thousands) 2017 2016 Service Cost $ 66 $ 76 Interest Cost 237 267 Expected return on plan assets (346 ) (361 ) Amortization of unrecognized actuarial loss 100 163 Net periodic pension costs $ 57 $ 145 Changes in plan assets and benefit obligations recognized in accumulated other comprehensive income are as follows: December 31, (In thousands) 2017 2016 Amortization of actuarial (loss) $ (100 ) $ (163 ) Actuarial (gain) loss (54 ) (351 ) Total recognized in accumulated other comprehensive income (154 ) (514 ) Total recognized in net periodic pension cost recognized and other comprehensive income $ (97 ) $ (369 ) The amounts in accumulated other comprehensive income that have not yet been recognized as components of net periodic benefit cost are a net loss of $1.3 million and $1.5 million in 2017 and 2016, respectively. The Company expects to make no cash contributions to the pension trust during 2018. The amount expected to be amortized from other comprehensive income into net periodic pension cost over the next fiscal year is $83 thousand . The principal actuarial assumptions used were as follows: December 31, 2017 2016 Projected benefit obligation Discount rate 3.510 % 3.980 % Net periodic pension cost Discount rate 3.980 % 4.170 % Long term rate of return on plan assets 7.000 % 7.000 % The discount rate that is used in the measurement of the pension obligation is determined by comparing the expected future retirement payment cash flows of the pension plan to the Citigroup Above Median Double-A Curve as of the measurement date. The expected long-term rate of return on Plan assets reflects long-term earnings expectations on existing Plan assets and those contributions expected to be received during the current plan year. In estimating that rate, appropriate consideration was given to historical returns earned by Plan assets in the fund and the rates of return expected to be available for reinvestment. The rates of return were adjusted to reflect current capital market assumptions and changes in investment allocations. The Company’s overall investment strategy with respect to the Plan’s assets is primarily for preservation of capital and to provide regular dividend and interest payments. The Plan’s targeted asset allocation is 65% equity securities via investment in the Long-Term Growth - Equity Portfolio (‘LTGE’), 34% intermediate-term investment grade bonds via investment in the Long-Term Growth - Fixed-Income Portfolio (‘LTGFI’), and 1% in cash equivalents portfolio (for liquidity). Equity securities include investments in a diverse mix of equity funds to gain exposure in the US and international markets. The fixed income portion of the Plan assets is a diversified portfolio that primarily invests in intermediate-term bond funds. The overall rate of return is based on the historical performance of the assets applied against the Plan’s target allocation, and is adjusted for the long-term inflation rate. The fair values for investment securities are determined by quoted prices in active markets, if available (Level 1). For securities where quoted prices are not available, fair values are calculated based on market prices of similar securities (Level 2). For securities where quoted prices or market prices of similar securities are not available, fair values are calculated using discounted cash flows or other market indicators (Level 3). The fair values of the Plan’s assets by category and level within the fair value hierarchy are as follows at December 31, 2017: December 31, 2017 Asset Category (In thousands) Total Level 1 Level 2 Equity Mutual Funds: Large-Cap $ 1,820 $ — $ 1,820 Mid-Cap 439 — 439 Small-Cap 438 — 438 International 893 — 893 Fixed Income Funds Fixed Income - US Core 1,308 — 1,308 Intermediate Duration 437 — 437 Cash Equivalents - money market 111 29 82 Total $ 5,446 $ 29 $ 5,417 The fair values of the Plan’s assets by category and level within the fair value hierarchy are as follows at December 31, 2016: December 31, 2016 Asset Category (In thousands) Total Level 1 Level 2 Equity Mutual Funds: Large-Cap $ 1,624 $ — $ 1,624 Mid-Cap 401 — 401 Small-Cap 415 — 415 International 757 — 757 Fixed Income Funds Fixed Income - US Core 1,378 — 1,378 Intermediate Duration 472 — 472 Cash Equivalents - money market 74 30 44 Total $ 5,121 $ 30 $ 5,091 The Plan did not hold any assets classified as Level 3, and there were no transfers between levels during 2017 or 2016. Estimated benefit payments under the Company’s pension plans over the next ten years at December 31, 2017 are as follows: Year Payments (In thousands) 2018 343 2019 380 2020 372 2021 361 2022 386 2023 - 2027 1,792 Postretirement Benefits The Company has an unfunded post-retirement medical plan which was assumed in connection with the Rome Bancorp acquisition in 2011. The postretirement plan has been modified so that participation is closed to those employees who did not meet the retirement eligibility requirements by March 31, 2011. The Company contributes partially to medical benefits and life insurance coverage for retirees. Such retirees and their surviving spouses are responsible for the remainder of the medical benefits, including increases in premiums levels, between the total premium and the Company’s contribution. The Company also has an executive long-term care (“LTC”) postretirement benefit plan which started August 1, 2014. The LTC plan reimburses executives for certain costs in the event of a future chronic illness. Funding of the plan comes from Company paid insurance policies or direct payments. At plan’s inception, a $558 thousand benefit obligation was recorded against equity representing the prior service cost of plan participants. Information regarding the post-retirement plan is as follows: December 31, (In thousands) 2017 2016 Change in accumulated postretirement benefit obligation: Accumulated post-retirement benefit obligation at beginning of year $ 3,249 $ 3,039 Service Cost 35 32 Interest cost 131 129 Participant contributions 46 47 Actuarial loss (gain) 326 130 Benefits paid (94 ) (128 ) Accumulated post-retirement benefit obligation at end of year $ 3,693 $ 3,249 Change in plan assets: Fair value of plan assets at beginning of year $ — $ — Contributions by employer 48 81 Contributions by participant 46 47 Benefits paid (94 ) (128 ) Fair value of plan assets at end of year $ — $ — Amounts Recognized in Consolidated Balance Sheet Other Liabilities $ 3,693 $ 3,249 Net periodic post-retirement cost is comprised of the following: December 31, (In thousands) 2017 2016 Service cost $ 35 $ 32 Interest costs 131 129 Amortization of net prior service credit 83 83 Amortization of net actuarial loss — — Net periodic post-retirement costs $ 249 $ 244 Changes in benefit obligations recognized in accumulated other comprehensive income are as follows: December 31, (In thousands) 2017 2016 Amortization of actuarial loss $ — $ — Amortization of prior service credit (83 ) (83 ) Net actuarial (gain) loss 199 (126 ) Total recognized in accumulated other comprehensive income 116 (209 ) Accrued post-retirement liability recognized $ 1,918 $ 1,718 The amounts in accumulated other comprehensive income that have not yet been recognized as components of net periodic benefit cost are as follows: December 31, (In thousands) 2017 2016 Net prior service cost (credit) $ 1,576 $ 1,659 Net actuarial (gain) loss 199 (126 ) Total recognized in accumulated other comprehensive income $ 1,775 $ 1,533 The amount expected to be amortized from other comprehensive income into net periodic postretirement cost over the next fiscal year is $83 thousand . The discount rates used in the measurement of the postretirement medical and LTC plan obligations are determined by comparing the expected future retirement payment cash flows of the plans to the Citigroup Above Median Double-A Curve as of the measurement date. The assumed discount rates on a weighted-average basis were 3.44% and 3.91% as of December 31, 2017 and December 31, 2016, respectively. The assumed health care cost trend rate used in measuring the accumulated post-retirement benefit medical obligation is expected to be 7.75% for 2018, and is gradually expected to decrease to 3.89% by 2076. This assumption may have a significant effect on the amounts reported. However, as noted above, increases in premium levels are the financial responsibility of the plan beneficiary. Thus an increase or decrease in 1% of the health care cost trend rates utilized would have had an immaterial effect on the service and interest cost as well as the accumulated post-retirement benefit obligation for the postretirement plan as of December 31, 2017. For participants in the LTC plan covered by insurance policies, no increase in annual premiums is assumed based on the history of the corresponding insurance provider. Estimated benefit payments under the post-retirement benefit plan over the next ten years at December 31, 2017 are as follows: Year Payments (In thousands) 2018 103 2019 103 2020 102 2021 106 2022 109 2023 - 2027 548 401(k) Plan The Company provides a 401(k) Plan in which most eligible employees participate. Expense related to the plan was $3.4 million in 2017, $3.9 million in 2016, and $3.6 million in 2015. Employee Stock Ownership Plan (“ESOP”) As part of acquisitions in 2015, 2012 and two during 2011, the Company acquired ESOP plans that were frozen and terminated prior to the completion of those transactions. On the acquisition dates, all amounts in the plans were vested and the loans under the plans were repaid from the sale proceeds of unallocated shares. Other Plans The Company maintains a supplemental executive retirement plan (“SERP”) for a few select executives. Benefits generally commence no earlier than age sixty-two and are payable at the executive’s option, either as an annuity or as a lump sum. Some of these SERPs were assumed in connection with the Beacon acquisition in 2012. A SERP was acquired in connection with the Hampden Bank acquisition with an accrued liability of $1.4 million at acquisition date. At year-end 2017, the liability was $1.1 million and $1.2 million at year-end 2016. At year-end 2017 and 2016, the accrued liability for these SERPs were $8.3 million and $7.4 million , respectively. SERP expense was $968 thousand in 2017, $917 thousand in 2016, and $752 thousand in 2015, and is recognized over the required service period. The Company assumed split-dollar life insurance agreements with the acquisition of Hampden Bank with an accrued liability of $860 thousand at acquisition date in April 2015. At year-end 2017, the liability was $1.2 million and $1.2 million as of year-end 2016. The Company assumed split-dollar life insurance agreements with the acquisition of Commerce Bank with an accrued liability of $2.7 million at acquisition date in October 2017. At year-end 2017, the liability was $2.8 million . The Company has endorsement split-dollar arrangements pertaining to certain current and prior executives. Under these arrangements, the Company purchased policies insuring the lives of the executives, and separately entered into agreements to split the policy benefits with the executive. There are no post-retirement benefits associated with these policies.

INCOME TAXES

INCOME TAXES	12 Months Ended
	Dec. 31, 2017
Income Tax Disclosure [Abstract]
INCOME TAXES	INCOME TAXES Provision for Income Taxes The components of the Company’s provision for income taxes for the years ended December 31, 2017, 2016, and 2015 were, as follows: (In thousands) 2017 2016 2015 Current: Federal tax expense $ 11,686 $ 6,758 $ 4,696 State tax expense 1,112 1,101 (1,631 ) Total current expense 12,798 7,859 3,065 Deferred: Federal tax expense 29,824 9,438 2,023 State tax expense 1,805 1,591 (24 ) Total deferred tax expense (1) 31,629 11,029 1,999 Change in valuation allowance 75 (104 ) — Total income tax expense $ 44,502 $ 18,784 $ 5,064 (1) 2017 Deferred tax expense of $31.6 million includes an $18.1 million charge to re-measure the net deferred tax asset at December 31, 2017 pursuant to the reduction in the corporate income tax rate from 35% to 21%, effective January 1, 2018, per the Tax Cuts and Jobs Act enacted on December 22, 2017. Effective Tax Rate The following is a reconciliation of the statutory federal income tax rate to the Company’s effective tax rate for the years ended December 31, 2017, 2016, and 2015: 2017 2016 2015 (In thousands, except rates) Amount Rate Amount Rate Amount Rate Statutory tax rate $ 34,912 35.0 % $ 27,108 35.0 % $ 19,104 35.0 % Increase (decrease) resulting from: State taxes, net of federal tax benefit 2,232 2.2 1,675 2.2 (974 ) (1.8 ) Tax exempt income - investments, net (5,395 ) (5.4 ) (3,849 ) (5.0 ) (3,463 ) (6.3 ) Bank-owned life insurance (1,556 ) (1.6 ) (1,364 ) (1.8 ) (1,284 ) (2.4 ) Non-deductible merger costs 368 0.4 542 0.7 422 0.8 Non-deductible goodwill on disposal operations sale — — — — 313 0.6 Tax credits, net of basis reduction (4,656 ) (4.7 ) (6,225 ) (8.0 ) (8,308 ) (15.2 ) Change in valuation allowance 75 0.1 125 0.2 — — Impact of federal tax reform enactment 18,145 18.2 — — — — Other, net 377 0.4 772 1.0 (746 ) (1.4 ) Effective tax rate $ 44,502 44.6 % $ 18,784 24.3 % $ 5,064 9.3 % On December 22, 2017, the SEC staff issued Staff Accounting Bulletin No. 118 (SAB 118) to address the application of US GAAP in situations when a registrant does not have the necessary information available to complete the accounting for certain income tax effects of the Tax Cuts and Jobs Act (the "2017 Act"). SAB 118 allows for adjustments to the tax provision for up to one year from the enactment date (the measurement period). Any provisional amounts or adjustments to provisional amounts included in the Company’s financial statements during the measurement period will be included in income from continuing operations as an adjustment to tax expense or benefit in the reporting period the amounts are determined. The Company recorded provisional amounts of deferred income taxes using reasonable estimates in five areas where the information necessary to determine the final deferred tax asset or liability was either not available, not prepared, or not sufficiently analyzed as of the report filing date: 1) The deferred tax liability for temporary differences between the tax and financial reporting bases of fixed assets is awaiting completion and implementation of software updates to process the calculations associated with the Act's provisions allowing for direct expensing of qualified assets. 2) The net deferred tax asset for temporary differences associated with Commerce acquired tax attributes is awaiting final determinations of those amounts, some of which remain provisional. 3) The net deferred tax liability for loan servicing rights is awaiting formal approval from the Internal Revenue Service of a requested tax accounting method change with respect to these rights. 4) The net deferred tax asset for temporary differences associated with equity investments in partnerships is awaiting the receipt of Schedules K-1 from outside preparers, which is necessary to determine the 2017 tax impact from these investments. In a fifth area, the Company made no adjustments to deferred tax assets representing future deductions for accrued compensation that may be subject to new limitations under Internal Revenue Code Section 162(m) which, generally, limits the annual deduction for certain compensation paid to certain employees to $1 million. As of the report filing date, there is uncertainty regarding how the newly-enacted rules in this area apply to existing contracts. Consequently, the Company is seeking further clarification of these matters before completing the analysis. The Company will complete and record the income tax effects of these provisional items during the period the necessary information becomes available. This measurement period will not extend beyond December 22, 2018. Deferred Tax Liabilities and Assets As of December 31, 2017 and 2016, significant components of the Company’s deferred tax assets and liabilities were, as follows: (In thousands) 2017 2016 Deferred tax assets: Allowance for loan losses $ 14,578 $ 17,747 Tax credit carryforwards 4,100 4,100 Unrealized capital loss on tax credit investments 6,502 6,999 Employee benefit plans 4,983 7,813 Purchase accounting adjustments 37,843 23,520 Net operating loss carryforwards 1,374 2,643 Other 2,332 4,997 Deferred tax assets, net before valuation allowances 71,712 67,819 Valuation allowance (200 ) (125 ) Deferred tax assets, net of valuation allowances $ 71,512 $ 67,694 Deferred tax liabilities: Net unrealized gain on swaps, securities available for sale, and pension in OCI $ (1,888 ) $ (5,884 ) Premises and equipment (1,126 ) (2,519 ) Loan servicing rights (2,174 ) (4,546 ) Deferred loan fees (3,900 ) — Intangible amortization (15,001 ) (11,543 ) Other (362 ) (2,074 ) Deferred tax liabilities $ (24,451 ) $ (26,566 ) Deferred tax assets, net $ 47,061 $ 41,128 The Company’s net deferred tax asset increased by $5.9 million during 2017, including $34.5 million from the acquisition of Commerce resulting in a reduction in goodwill, $3.1 million deferred tax benefit recognized as an increase in shareholder's equity, and an $18.1 million deferred tax expense to re-measure the net deferred tax assets as a result of the federal tax reform enactment. Refer to Note 2 - Acquisitions for more information about the acquisition of Commerce. Deferred tax assets, net of valuation allowances, are expected to be realized through the reversal of existing taxable temporary differences and future taxable income. Valuation Allowances The components of the Company’s valuation allowance on its deferred tax asset, net as of December 31, 2017 and 2016 were, as follows: (in thousands) 2017 2016 State tax basis difference, net of Federal tax benefit $ (200 ) $ (125 ) Valuation allowances $ (200 ) $ (125 ) The state tax basis difference, net of Federal tax benefit was originally recorded in 2012, due to management’s assessment that it is more likely than not that certain deferred tax assets recorded for the difference between the book basis and the state tax basis in certain tax credit limited partnership investments (LPs) will not be realized. Management anticipates that the remaining excess state tax basis will be realized as a capital loss upon disposition, and that it is unlikely that the Company will have capital gains against which to offset such capital losses. During 2017, the valuation allowance increased by $75 thousand and the change was recorded as an increase to income tax expense. The valuation allowances as of December 31, 2017 are subject to change in the future as the Company continues to periodically assess the likelihood of realizing its deferred tax assets. Tax Attributes At December 31, 2017, the Company has $6.5 million of federal net operating loss carryforwards, $3.3 million of New Jersey net operating loss carryforwards, and $13.9 million of Connecticut net operating loss carryforwards available that were obtained through acquisition, the utilization of which are limited under Internal Revenue Code Section 382. No deferred tax asset has been recorded for the Connecticut net operating loss carryforward since the state of Connecticut does not currently allow a deduction for net operating losses. These net operating losses begin to expire in 2024. The related deferred tax asset is $1.4 million . In addition, the Company has alternative minimum tax credit carryforwards of $4.0 million , which the Company expects to be monetized over the next two years. Unrecognized Tax Benefits On a periodic basis, the Company evaluates its income tax positions based on tax laws and regulations and financial reporting considerations, and records adjustments as appropriate. This evaluation takes into consideration the status of taxing authorities’ current examinations of the Company’s tax returns, recent positions taken by the taxing authorities on similar transactions, if any, and the overall tax environment in relation to uncertain tax positions. The following table presents changes in unrecognized tax benefits for the years ended December 31, 2017, 2016, and 2015: (In thousands) 2017 2016 2015 Unrecognized tax benefits at January 1 $ 460 $ 307 $ 553 Increase in gross amounts of tax positions related to prior years — 270 — Decrease in gross amounts of tax positions related to prior years (156 ) — — Decrease due to settlement with taxing authority — — — Increase in gross amounts of tax positions related to current year — — — Decrease due to lapse in statute of limitations — (117 ) (246 ) Unrecognized tax benefits at December 31 $ 304 $ 460 $ 307 It is reasonably possible that over the next twelve months the amount of unrecognized tax benefits may change from the reevaluation of uncertain tax positions arising in examinations, in appeals, or in the courts, or from the closure of tax statutes. The Company does not expect any significant changes in unrecognized tax benefits during the next twelve months. All of the Company’s unrecognized tax benefits, if recognized, would be recorded as a component of income tax expense, therefore, affecting the effective tax rate. The Company recognizes interest and penalties, if any, related to the liability for uncertain tax positions as a component of income tax expense. The accrual for interest and penalties was not material for all years presented. The Company and its subsidiaries file income tax returns in the U.S. federal jurisdiction as well as in various states. In the normal course of business, the Company is subject to U.S. federal, state, and local income tax examinations by tax authorities. The Company is no longer subject to examination for tax years prior to 2014 including any related income tax filings from its recent acquisitions. The Company has been selected for audit in the state of New York for tax years 2013-2014.

DERIVATIVE INSTRUMENTS AND HEDG

DERIVATIVE INSTRUMENTS AND HEDGING ACTIVITIES	12 Months Ended
	Dec. 31, 2017
Derivative Instruments and Hedging Activities Disclosure [Abstract]
DERIVATIVE INSTRUMENTS AND HEDGING ACTIVITIES	DERIVATIVE INSTRUMENTS AND HEDGING ACTIVITIES At year-end 2017, the Company held derivatives with a total notional amount of $2.5 billion . The Company had economic hedges and non-hedging derivatives totaling $2.3 billion and $194.0 million , respectively, which are not designated as hedges for accounting purposes and are therefore recorded at fair value with changes in fair value recorded directly through earnings. Economic hedges included interest rate swaps totaling $1.9 billion , risk participation agreements with dealer banks of $142.1 million , and $276.6 million in forward commitment contracts. As part of the Company’s risk management strategy, the Company enters into interest rate swap agreements to mitigate the interest rate risk inherent in certain of the Company’s assets and liabilities. Interest rate swap agreements involve the risk of dealing with both Bank customers and institutional derivative counterparties and their ability to meet contractual terms. The agreements are entered into with counterparties that meet established credit standards and contain master netting and collateral provisions protecting the at-risk party. The derivatives program is overseen by the Risk Management Committee of the Company’s Board of Directors. Based on adherence to the Company’s credit standards and the presence of the netting and collateral provisions, the Company believes that the credit risk inherent in these contracts was not significant at December 31, 2017. The Company pledged collateral to derivative counterparties in the form of cash totaling $2.1 million and securities with an amortized cost of $24.4 million and a fair value of $24.4 million at year-end 2017. At December 31, 2016, the Company pledged cash collateral of $0.9 million and securities with an amortized cost of $47.8 million and a fair value of $47.9 million . The Company does not typically require its commercial customers to post cash or securities as collateral on its program of back-to-back economic hedges. However certain language is written into the International Swaps Dealers Association, Inc. (“ISDA”) and loan documents where, in default situations, the Bank is allowed to access collateral supporting the loan relationship to recover any losses suffered on the derivative asset or liability. The Company may need to post additional collateral in the future in proportion to potential increases in unrealized loss positions. Information about interest rate swap agreements and non-hedging derivative assets and liabilities at December 31, 2017 follows: Notional Amount Weighted Average Maturity Weighted Average Rate Estimated Fair Value Asset (Liability) December 31, 2017 Received Contract pay rate (In thousands) (In years) (In thousands) Cash flow hedges: Interest rate swaps on FHLBB borrowings $ — 0 — % — % $ — Total cash flow hedges — — Economic hedges: Interest rate swap on tax advantaged economic development bond 10,755 11.9 1.73 % 5.09 % (1,649 ) Interest rate swaps on loans with commercial loan customers 943,795 5.9 3.26 % 4.25 % (3,195 ) Reverse interest rate swaps on loans with commercial loan customers 943,795 5.9 4.25 % 3.26 % 3,204 Risk participation agreements with dealer banks 142,054 8.4 (26 ) Forward sale commitments 276,572 0.2 (123 ) Total economic hedges 2,316,971 (1,789 ) Non-hedging derivatives: Commitments to lend 193,966 0.2 5,259 Total non-hedging derivatives 193,966 5,259 Total $ 2,510,937 $ 3,470 Information about interest rate swap agreements and non-hedging derivative asset and liabilities at December 31, 2016 follows: Notional Amount Weighted Average Maturity Weighted Average Rate Estimated Fair Value Asset (Liability) December 31, 2016 Received Contract pay rate (In thousands) (In years) (In thousands) Cash flow hedges: Forward-starting interest rate swaps on FHLBB borrowings $ 300,000 2.3 0.63 % 2.29 % $ (6,573 ) Total cash flow hedges 300,000 (6,573 ) Economic hedges: Interest rate swap on tax advantaged economic development bond 11,386 12.9 0.98 % 5.09 % (2,021 ) Interest rate swaps on loans with commercial loan customers 668,541 6.2 2.43 % 4.21 % (6,752 ) Reverse interest rate swaps on loans with commercial loan customers 668,541 6.2 4.21 % 2.43 % 7,077 Risk participation agreements with dealer banks 83,360 11.6 5 Forward sale commitments 259,889 0.2 722 Total economic hedges 1,691,717 (969 ) Non-hedging derivatives: Commitments to lend 208,145 0.2 4,738 Total non-hedging derivatives 208,145 4,738 Total $ 2,199,862 $ (2,804 ) Cash Flow Hedges In the first quarter of 2017, the Company maintained six interest rate swap contracts with an aggregate notional value of $300 million with original durations of three years . This hedge strategy converted one month rolling FHLB borrowings based on the FHLB’s one month fixed interest rate to fixed interest rates, thereby protecting the Company from floating interest rate variability. On February 7, 2017, the Company terminated all of its interest rate swaps associated with FHLB advances with 1-month LIBOR based floating interest rates of an aggregate notional amount of $300 million . As of March 31, 2017, the Company no longer held the FHLB advances associated with the interest rate swaps. As a result, the Company reclassified $6.6 million of losses from the effective portion of the unrealized changes in the fair value of the terminated derivatives from other comprehensive income to non-interest income as the forecasted transactions to the related FHLB advances will not occur. For the periods presented prior to the termination, the effective portion of unrealized changes in the fair value of derivatives accounted for as cash flow hedges was reported in other comprehensive income. Each quarter, the Company assessed the effectiveness of each hedging relationship by comparing the changes in cash flows of the derivative hedging instrument with the changes in cash flows of the designated hedged item or transaction. Hedge ineffectiveness on interest rate swaps designated as cash flow hedges was immaterial to the Company’s financial statements during the years ended December 31, 2017 and 2016. Amounts included in the Consolidated Statements of Income and in the other comprehensive income section of the Consolidated Statements of Comprehensive Income (related to interest rate derivatives designated as hedges of cash flows), were as follows: Years Ended December 31, (In thousands) 2017 2016 2015 Interest rate swaps on FHLBB borrowings: Unrealized (loss) recognized in accumulated other comprehensive loss $ (449 ) $ (2,023 ) $ (5,232 ) Less: Reclassification of unrealized (loss) from accumulated other comprehensive loss to interest expense (393 ) (3,981 ) — Less: reclassification of unrealized (loss) from accumulated other (6,629 ) — — Net tax effect on items recognized in accumulated other comprehensive income (2,589 ) (835 ) 2,094 Other comprehensive income recorded in accumulated other comprehensive income, net of reclassification adjustments and tax effects $ 3,984 $ 1,123 $ (3,138 ) Economic hedges As of December 31, 2017 the Company has an interest rate swap with a $10.8 million notional amount to swap out the fixed rate of interest on an economic development bond bearing a fixed rate of 5.09% , currently within the Company’s trading portfolio under the fair value option, in exchange for a LIBOR-based floating rate. The intent of the economic hedge is to improve the Company’s asset sensitivity to changing interest rates in anticipation of favorable average floating rates of interest over the 21 -year life of the bond. The fair value changes of the economic development bond are mostly offset by fair value changes of the related interest rate swap. The Company also offers certain derivative products directly to qualified commercial borrowers. The Company economically hedges derivative transactions executed with commercial borrowers by entering into mirror-image, offsetting derivatives with third-party financial institutions. The transaction allows the Company’s customer to convert a variable-rate loan to a fixed rate loan. Because the Company acts as an intermediary for its customer, changes in the fair value of the underlying derivative contracts mostly offset each other in earnings. Credit valuation adjustments arising from the difference in credit worthiness of the commercial loan and financial institution counterparties totaled $(316) thousand at year-end 2017. The interest income and expense on these mirror image swaps exactly offset each other. The Company has risk participation agreements with dealer banks. Risk participation agreements occur when the Company participates on a loan and a swap where another bank is the lead. The Company earns a fee to take on the risk associated with having to make the lead bank whole on Berkshire’s portion of the pro-rated swap should the borrower default. The Company utilizes forward sale commitments to hedge interest rate risk and the associated effects on the fair value of interest rate lock commitments and loans held for sale. The forward sale commitments are accounted for as derivatives with changes in fair value recorded in current period earnings. The company uses the following types of forward sale commitments contracts: • Best efforts loan sales, • Mandatory delivery loan sales, and • To be announced (TBA) mortgage-backed securities sales. A best efforts contract refers to a loan sales agreement where the Company commits to deliver an individual mortgage loan of a specified principal amount and quality to an investor if the loan to the underlying borrower closes. The Company may enter into a best efforts contract once the price is known, which is shortly after the potential borrower’s interest rate is locked. A mandatory delivery contract is a loan sales agreement where the Company commits to deliver a certain principal amount of mortgage loans to an investor at a specified price on or before a specified date. Generally, the Company may enter into mandatory delivery contracts shortly after the loan closes with a customer. The Company may sell to-be-announced mortgage-backed securities to hedge the changes in fair value of interest rate lock commitments and held for sale loans, which do not have corresponding best efforts or mandatory delivery contracts. These security sales transactions are closed once mandatory contracts are written. On the closing date the price of the security is locked-in, and the sale is paired-off with a purchase of the same security. Settlement of the security purchase/sale transaction is done with cash on a net-basis. Non-hedging derivatives The Company enters into commitments to lend for residential mortgage loans, which commit the Company to lend funds to a potential borrower at a specific interest rate and within a specified period of time. Commitments that relate to the origination of mortgage loans that will be held for sale are considered derivative financial instruments under applicable accounting guidance. Outstanding commitments expose the Company to the risk that the price of the mortgage loans underlying the commitments may decline due to increases in mortgage interest rates from inception of the rate lock to the funding of the loan. The commitments are free-standing derivatives which are carried at fair value with changes recorded in non-interest income in the Company’s consolidated statements of income. Changes in the fair value of commitments subsequent to inception are based on changes in the fair value of the underlying loan resulting from the fulfillment of the commitment and changes in the probability that the loan will fund within the terms of the commitment, which is affected primarily by changes in interest rates and the passage of time. Amounts included in the Consolidated Statements of Income related to economic hedges and non-hedging derivatives were as follows: Years Ended December 31, (In thousands) 2017 2016 2015 Economic hedges Interest rate swap on industrial revenue bond: Unrealized gain (loss) recognized in other non-interest income $ 371 $ (75 ) $ (344 ) Interest rate swaps on loans with commercial loan customers: Unrealized gain recognized in other non-interest income 3,557 1,312 (4,852 ) Reverse interest rate swaps on loans with commercial loan customers: Unrealized (loss) recognized in other non-interest income (3,557 ) (1,312 ) 4,852 (Unfavorable) Favorable change in credit valuation adjustment recognized in other non-interest income (316 ) 338 (51 ) Risk Participation Agreements: Unrealized (loss) recognized in other non-interest income (31 ) (61 ) (36 ) Forward Commitments: Unrealized gain (loss) recognized in non-interest income (123 ) (1,176 ) (247 ) Realized (loss) in non-interest income (1,764 ) (3,705 ) 45 Non-hedging derivatives Commitments to lend: Unrealized gain recognized in non-interest income $ 5,259 $ 8,373 $ 2,436 Realized gain in non-interest income 50,879 3,650 1,899 Assets and Liabilities Subject to Enforceable Master Netting Arrangements Interest Rate Swap Agreements (“Swap Agreements”) The Company enters into swap agreements to facilitate the risk management strategies for commercial banking customers. The Company mitigates this risk by entering into equal and offsetting swap agreements with highly rated third party financial institutions. The swap agreements are free-standing derivatives and are recorded at fair value in the Company’s consolidated statements of condition. The Company is party to master netting arrangements with its financial institution counterparties; however, the Company does not offset assets and liabilities under these arrangements for financial statement presentation purposes. The master netting arrangements provide for a single net settlement of all swap agreements, as well as collateral, in the event of default on, or termination of, any one contract. Collateral generally in the form of marketable securities is received or posted by the counterparty with net liability positions, respectively, in accordance with contract thresholds. The Company had net asset positions with its financial institution counterparties totaling $1.1 million and $49 thousand as of December 31, 2017 and December 31, 2016, respectively. The Company had net asset positions with its commercial banking counterparties totaling $8.6 million and $11.5 million as of December 31, 2017 and December 31, 2016, respectively. The Company had net liability positions with its financial institution counterparties totaling $5.9 million and $15.4 million as of December 31, 2017 and December 31, 2016, respectively. At December 31, 2017, the Company had net liability positions with its commercial banking counterparties totaling $5.4 million and $4.4 million as of December 31, 2017 and December 31, 2016, respectively. The collateral posted by the Company that covered liability positions was $5.9 million and $19.8 million as of December 31, 2017 and December 31, 2016, respectively. The following table presents the assets and liabilities subject to an enforceable master netting arrangement as of December 31, 2017 and December 31, 2016 : Offsetting of Financial Assets and Derivative Assets Gross Gross Amounts Net Amounts of Assets Gross Amounts Not Offset in the Statements Financial Cash (in thousands) Net Amount As of December 31, 2017 Interest Rate Swap Agreements: Institutional counterparties $ 2,692 $ (1,622 ) $ 1,070 $ — $ — $ 1,070 Commercial counterparties 8,577 — 8,577 — — 8,577 Total $ 11,269 $ (1,622 ) $ 9,647 $ — $ — $ 9,647 Offsetting of Financial Liabilities and Derivative Liabilities Gross Gross Amounts Net Amounts of Liabilities Gross Amounts Not Offset in the Statements Financial Cash (in thousands) Net Amount As of December 31, 2017 Interest Rate Swap Agreements: Institutional counterparties $ (8,777 ) $ 2,835 $ (5,942 ) $ 3,982 $ 1,960 $ — Commercial counterparties (5,375 ) 2 (5,373 ) — — (5,373 ) Total $ (14,152 ) $ 2,837 $ (11,315 ) $ 3,982 $ 1,960 $ (5,373 ) Offsetting of Financial Assets and Derivative Assets Gross Gross Amounts Net Amounts of Assets Gross Amounts Not Offset in the Statements Financial Cash (in thousands) Net Amount As of December 31, 2016 Interest Rate Swap Agreements: Institutional counterparties $ 49 $ — $ 49 $ — $ — $ 49 Commercial counterparties 11,461 — 11,461 — — 11,461 Total $ 11,510 $ — $ 11,510 $ — $ — $ 11,510 Offsetting of Financial Liabilities and Derivative Liabilities Gross Gross Amounts Net Amounts of Liabilities Gross Amounts Not Offset in the Statements Financial Cash (in thousands) Net Amount As of December 31, 2016 Interest Rate Swap Agreements: Institutional counterparties $ (20,077 ) $ 4,689 $ (15,388 ) $ 14,738 $ 650 $ — Commercial counterparties (4,407 ) 23 (4,384 ) — — (4,384 ) Total $ (24,484 ) $ 4,712 $ (19,772 ) $ 14,738 $ 650 $ (4,384 )

OTHER COMMITMENTS, CONTINGENCIE

OTHER COMMITMENTS, CONTINGENCIES, AND OFF-BALANCE SHEET ACTIVITIES	12 Months Ended
	Dec. 31, 2017
Commitments and Contingencies Disclosure [Abstract]
OTHER COMMITMENTS, CONTINGENCIES, AND OFF-BALANCE SHEET ACTIVITIES	OTHER COMMITMENTS, CONTINGENCIES, AND OFF-BALANCE SHEET ACTIVITIES Credit Related Financial Instruments. The Company is a party to financial instruments with off-balance-sheet risk in the normal course of business to meet the financing needs of its customers. These financial instruments include commitments to extend credit and standby letters of credit. Such commitments involve, to varying degrees, elements of credit, and interest rate risk in excess of the amount recognized in the accompanying consolidated balance sheets. The Company’s exposure to credit loss in the event of non-performance by the other party to the financial instrument is represented by the contractual amount of these commitments. The Company uses the same credit policies in making commitments as it does for on-balance-sheet instruments. A summary of financial instruments outstanding whose contract amounts represent credit risk is as follows at year-end: (In thousands) 2017 2016 Commitments to originate new loans $ 244,252 $ 243,519 Unused funds on commercial and other lines of credit 678,567 574,043 Unadvanced funds on home equity lines of credit 297,367 281,621 Unadvanced funds on construction and real estate loans 360,472 320,635 Standby letters of credit 13,613 14,939 Lease obligation 11,323 11,639 Total $ 1,605,594 $ 1,446,396 Commitments to extend credit are agreements to lend to a customer as long as there is no violation of any condition established in the contract. Commitments generally have fixed expiration dates or other termination clauses and may require payment of a fee. The commitments for lines of credit may expire without being drawn upon. Therefore, the total commitment amounts do not necessarily represent future cash requirements. The Company evaluates each customer’s creditworthiness on a case-by-case basis. Standby letters of credit are conditional commitments issued by the Company to guarantee the performance of a customer to a third party. These letters of credit are primarily issued to support borrowing arrangements. The credit risk involved in issuing letters of credit is essentially the same as that involved in extending loan facilities to customers. The Company considers standby letters of credit to be guarantees and the amount of the recorded liability related to such guarantees was not material at year-end 2017 and 2016. Operating Lease Commitments. Future minimum rental payments required under operating leases at year-end 2017 are as follows: 2018 — $12.8 million ; 2019 — $10.8 million ; 2020 — $9.3 million ; 2021 — $8.3 million ; 2022 — $7.6 million ; and all years thereafter — $47.6 million . The leases contain options to extend for periods up to twenty years. The cost of such rental options is not included above. Total rent expense for the years 2017, 2016, and 2015 amounted to $12.0 million , $8.3 million , and $7.5 million , respectively. Lease Obligations. Future obligations required under the capital lease at year-end 2017 are $647 thousand in 2018; $646 thousand in 2019; $644 thousand in 2020; $612 thousand in 2021; $583 thousand in 2022 and $5.0 million all years thereafter. Amortization under the capital lease is included with premises and equipment depreciation and amortization expense. Future obligations required under the financing lease at year-end 2017 are $86 thousand in 2018; $86 thousand in 2019; $86 thousand in 2020; $86 thousand in 2021; $87 thousand in 2022; and $1.5 million all years thereafter. Amortization under the financing lease is included with premises and equipment depreciation and amortization expense. Employment and Change in Control Agreements. The Company and the Bank have entered into a three -year employment agreement with one senior executive. The Company and the Bank also have change in control agreements with several officers which provide a severance payment in the event employment is terminated in conjunction with a defined change in control. Legal Claims. Various legal claims arise from time to time in the normal course of business. As of December 31, 2017, neither the Company nor the Bank was involved in any pending legal proceedings believed by management to be material to the Company’s financial condition or results of operations. Periodically, there have been various claims and lawsuits involving the Bank, such as claims to enforce liens, condemnation proceedings on properties in which the Bank holds security interests, claims involving the making and servicing of real property loans, and other issues incident to the Bank’s business. However, other than the items noted below, neither the Company nor the Bank is a party to any pending legal proceedings that it believes, in the aggregate, would have a material adverse effect on the financial condition or operations of the Company. Additionally, an estimate of future, probable losses cannot be estimated as of December 31, 2017. On April 28, 2016, Berkshire Hills and Berkshire Bank were served with a complaint filed in the United States District Court, District of Massachusetts, Springfield Division. The complaint was filed by an individual Berkshire Bank depositor, who claims to have filed the complaint on behalf of a purported class of Berkshire Bank depositors, and alleges violations of the Electronic Funds Transfer Act and certain regulations thereunder, among other matters. On July 15, 2016, the complaint was amended to add purported claims under the Massachusetts Consumer Protection Act. The complaint seeks, in part, compensatory, consequential, statutory, and punitive damages. Berkshire Hills and Berkshire Bank deny the allegations contained in the complaint and are vigorously defending this lawsuit. On January 29, 2018, the Bank was served with an amended complaint filed nominally against Berkshire Hills in the Business Litigation Session of the Massachusetts Superior Court sitting in Suffolk County. The amended complaint was filed by two residuary beneficiaries of an estate planning trust that was administered by the Bank as successor trustee following the death of the trust donor, and alleges the Bank breached its fiduciary duty and violated the Massachusetts Consumer Protection Act in the course of performing its duties as trustee. The complaint seeks compensatory, statutory, and punitive damages. Berkshire Hills and Berkshire Bank deny the allegations contained in the complaint and are vigorously defending this lawsuit.

SHAREHOLDERS' EQUITY AND EARNIN

SHAREHOLDERS' EQUITY AND EARNINGS PER COMMON SHARE	12 Months Ended
	Dec. 31, 2017
Stockholders' Equity Note [Abstract]
SHAREHOLDERS' EQUITY AND EARNINGS PER COMMON SHARE	SHAREHOLDERS’ EQUITY AND EARNINGS PER COMMON SHARE Minimum Regulatory Capital Requirements The Company and Bank are subject to various regulatory capital requirements administered by the federal and state banking agencies. Failure to meet minimum capital requirements can initiate certain mandatory and possibly additional discretionary actions by regulators that, if imposed, could have a direct material impact on the Company’s financial statements. Under capital adequacy guidelines and the regulatory framework for prompt corrective action, the Company and Bank must meet specific capital guidelines that involve quantitative measures of its assets, liabilities and certain off-balance-sheet items as calculated under regulatory accounting practices. The capital amounts and classification are also subject to qualitative judgments by the regulators about components, risk weighting and other factors. Quantitative measures established by regulation to ensure capital adequacy require the Company and Bank to maintain minimum amounts and ratios (set forth in the following table) of total and Tier 1 capital (as defined in the regulations) to risk-weighted assets (as defined) and of Tier 1 capital to average assets (as defined). As of year-end 2017 and 2016, the Bank and the Company met the capital adequacy requirements. Regulators may set higher expected capital requirements in some cases based on their examinations. Effective January 1, 2015, the Company and the Bank became subject to the Basel III rule that requires the Company and the Bank to assess their Common equity tier 1 capital to risk weighted assets and the Company and the Bank each exceed the minimum to be well capitalized. In addition, the final capital rules added a requirement to maintain a minimum conservation buffer, composed of Common equity tier 1 capital, of 2.5% of risk-weighted assets, to be phased in over three years and applied to the Common equity tier 1 risk-based capital ratio, the Tier 1 risk-based capital ratio and the Total risk-based capital ratio. Accordingly, banking organizations, on a fully phased in basis no later than January 1, 2019, must maintain a minimum Common equity tier 1 risk-based capital ratio of 7.0%, a minimum Tier 1 risk-based capital ratio of 8.5%, and a minimum Total risk-based capital ratio of 10.5%. The required minimum conservation buffer began to be phased in incrementally, starting at 0.625% on January 1, 2016 and increasing to 1.25% on January 1, 2017. It will increase to 1.875% on January 1, 2018 and 2.5% on January 1, 2019. The final capital rules impose restrictions on capital distributions and certain discretionary cash bonus payments if the minimum capital conservation buffer is not met. At December 31, 2017, the capital levels of both the Company and the Bank exceeded all regulatory capital requirements and their regulatory capital ratios were above the minimum levels. The capital levels of both the Company and the Bank at December 31, 2017 also exceeded the minimum capital requirements including the currently applicable capital conservation buffer of 1.25%. As of year-end 2017 and 2016 , the Bank met the conditions to be classified as “well capitalized” under the relevant regulatory framework. To be categorized as well capitalized, an institution must maintain minimum total risk-based, Tier 1 risk-based, and Tier 1 leverage ratios as set forth in the following tables. The Company and Bank’s actual and required capital amounts were as follows: Minimum Capital Requirement Minimum to be Well Capitalized Under Prompt Corrective Action Provisions Actual (Dollars in thousands) Amount Ratio Amount Ratio Amount Ratio December 31, 2017 Company (Consolidated) Total capital to risk-weighted assets $ 1,063,843 12.43 % $ 684,692 8.00 % $ 855,865 N/A Common Equity Tier 1 Capital to risk weighted assets 942,389 11.01 385,139 4.50 556,312 N/A Tier 1 capital to risk-weighted assets 954,103 11.15 513,519 6.00 684,692 N/A Tier 1 capital to average assets 954,103 9.01 342,346 4.00 427,932 N/A Bank Total capital to risk-weighted assets $ 954,172 11.17 % $ 683,103 8.00 % $ 853,879 10.00 % Common Equity Tier 1 Capital to risk weighted assets 881,324 10.32 384,245 4.50 555,021 6.50 Tier 1 capital to risk-weighted assets 881,324 10.32 512,327 6.00 683,103 8.00 Tier 1 capital to average assets 881,324 8.32 341,552 4.00 426,939 5.00 December 31, 2016 Company (Consolidated) Total capital to risk-weighted assets $ 803,618 11.87 % $ 541,603 8.00 % $ 677,004 N/A Common Equity Tier 1 Capital to risk weighted assets 670,120 9.90 304,652 4.50 440,053 N/A Tier 1 capital to risk-weighted assets 681,500 10.07 406,202 6.00 541,603 N/A Tier 1 capital to average assets 681,500 7.88 270,802 4.00 338,502 N/A Bank Total capital to risk-weighted assets $ 756,792 11.21 % $ 539,893 8.00 % $ 674,866 10.00 % Common Equity Tier 1 Capital to risk weighted assets 672,244 9.96 303,690 4.50 438,663 6.50 Tier 1 capital to risk-weighted assets 672,244 9.96 404,920 6.00 539,893 8.00 Tier 1 capital to average assets 672,244 7.84 269,920 4.00 337,433 5.00 Common stock The Bank is subject to dividend restrictions imposed by various regulators, including a limitation on the total of all dividends that the Bank may pay to the Company in any calendar year. The total of all dividends shall not exceed the Bank’s net income for the current year (as defined by statute), plus the Bank’s net income retained for the two previous years, without regulatory approval. Dividends from the Bank are an important source of funds to the Company to make dividend payments on its common and preferred stock, to make payments on its borrowings, and for its other cash needs. The ability of the Company and the Bank to pay dividends is dependent on regulatory policies and regulatory capital requirements. The ability to pay such dividends in the future may be adversely affected by new legislation or regulations, or by changes in regulatory policies relating to capital, safety and soundness, and other regulatory concerns. The payment of dividends by the Company is subject to Delaware law, which generally limits dividends to an amount equal to an excess of the net assets of a company (the amount by which total assets exceed total liabilities) over statutory capital, or if there is no excess, to the Company’s net profits for the current and/or immediately preceding fiscal year. Preferred stock As a provision of the merger agreement with Commerce, certain Commerce common stock was converted into the right to receive 0.465 shares of Series B Non-Voting Preferred Stock issued by the Company. Each preferred share is convertible into two shares of the Company's common stock under specified conditions. The shares are considered participating, but do not maintain preferential treatment over common shares. Proportional dividends on the preferred shares are not payable unless also declared for common shares. As of year-end 2017, 522 thousand preferred shares were issued and outstanding. Accumulated other comprehensive income Year-end components of accumulated other comprehensive income/(loss) are as follows: (In thousands) 2017 2016 Other accumulated comprehensive income/(loss), before tax: Net unrealized holding gain on AFS securities $ 10,034 $ 25,176 Net (loss) on effective cash flow hedging derivatives — (6,573 ) Net unrealized holding (loss) on pension plans (3,048 ) (2,954 ) Income taxes related to items of accumulated other comprehensive income/(loss): Net unrealized holding (gain) on AFS securities (4,026 ) (9,636 ) Net loss on effective cash flow hedging derivatives — 2,589 Net unrealized holding loss on pension plans 1,201 1,164 Accumulated other comprehensive income/(loss) $ 4,161 $ 9,766 The following table presents the components of other comprehensive income (loss) for the years ended December 31, 2017, 2016, and 2015: (In thousands) Before Tax Tax Effect Net of Tax Year Ended December 31, 2017 Net unrealized holding gain on AFS securities: Net unrealized (loss) arising during the period $ (2,544 ) $ 1,075 $ (1,469 ) Less: reclassification adjustment for gains realized in net income 12,598 (4,535 ) 8,063 Net unrealized holding (loss) on AFS securities (15,142 ) 5,610 (9,532 ) Net loss on cash flow hedging derivatives: Net unrealized (loss) arising during the period (449 ) 180 (269 ) Less: reclassification adjustment for (losses) realized in net income (7,022 ) 2,769 (4,253 ) Net gain on cash flow hedging derivatives 6,573 (2,589 ) 3,984 Net unrealized holding (loss) on pension plans Net unrealized (loss) arising during the period (311 ) 124 (187 ) Less: reclassification adjustment for losses realized in net income (217 ) 87 (130 ) Net unrealized holding (loss) on pension plans (94 ) 37 (57 ) Other Comprehensive Income(Loss) $ (8,663 ) $ 3,058 $ (5,605 ) (In thousands) Before Tax Tax Effect Net of Tax Year Ended December 31, 2016 Net unrealized holding gain on AFS securities: Net unrealized gain arising during the period $ 18,308 $ (6,979 ) $ 11,329 Less: reclassification adjustment for (losses) realized in net income (551 ) 220 (331 ) Net unrealized holding gain on AFS securities 18,859 (7,199 ) 11,660 Net (loss) on cash flow hedging derivatives: Net unrealized (loss) arising during the period (2,022 ) 754 (1,268 ) Less: reclassification adjustment for (losses) realized in net income (3,981 ) 1,589 (2,392 ) Net gain on cash flow hedging derivatives 1,959 (835 ) 1,124 Net unrealized holding gain on pension plans Net unrealized gain arising during the period 351 (155 ) 196 Less: reclassification adjustment for (losses) realized in net income (164 ) 73 (91 ) Net unrealized holding gain on pension plans 515 (228 ) 287 Other Comprehensive Income $ 21,333 $ (8,262 ) $ 13,071 (In thousands) Before Tax Tax Effect Net of Tax Year Ended December 31, 2015 Net unrealized holding gain on AFS securities: Net unrealized loss arising during the period $ (7,567 ) $ 2,793 $ (4,774 ) Less: reclassification adjustment for gains realized in net income 2,110 (847 ) 1,263 Net unrealized holding loss on AFS securities (9,677 ) 3,640 (6,037 ) Net (loss) on cash flow hedging derivatives: Net unrealized (loss) arising during the period (5,232 ) 2,094 (3,138 ) Less: reclassification adjustment for (losses) realized in net income — — — Net (loss) on cash flow hedging derivatives (5,232 ) 2,094 (3,138 ) Net unrealized holding (loss) on pension plans Net unrealized (loss) arising during the period (1,436 ) 572 (864 ) Less: reclassification adjustment for (losses) realized in net income (259 ) 104 (155 ) Net unrealized holding (loss) on pension plans (1,177 ) 468 (709 ) Other Comprehensive Loss $ (16,086 ) $ 6,202 $ (9,884 ) The following table presents the changes in each component of accumulated other comprehensive income (loss), for the years ended December 31, 2017 , 2016 , and 2015: (in thousands) Net unrealized holding gain (loss) on AFS Securities Net loss on effective cash flow hedging derivatives Net unrealized holding gain (loss) on pension plans Total Year Ended December 31, 2017 Balance at Beginning of Year $ 15,540 $ (3,984 ) $ (1,790 ) $ 9,766 Other comprehensive gain (loss) before reclassifications (1,469 ) (269 ) (187 ) (1,925 ) Amounts reclassified from accumulated other comprehensive income 8,063 (4,253 ) (130 ) 3,680 Total Other Comprehensive (Loss) Income (9,532 ) 3,984 (57 ) (5,605 ) Balance at End of Period $ 6,008 $ — $ (1,847 ) $ 4,161 Year Ended December 31, 2016 Balance at Beginning of Year $ 3,880 $ (5,108 ) $ (2,077 ) $ (3,305 ) Other comprehensive gain (loss) before reclassifications 11,329 (1,268 ) 196 10,257 Amounts reclassified from accumulated other comprehensive income (331 ) (2,392 ) (91 ) (2,814 ) Total Other Comprehensive Income 11,660 1,124 287 13,071 Balance at End of Period $ 15,540 $ (3,984 ) $ (1,790 ) $ 9,766 Year Ended December 31, 2015 Balance at Beginning of Year $ 9,916 $ (1,969 ) $ (1,368 ) $ 6,579 Other comprehensive gain (loss) Before reclassifications (4,774 ) (3,138 ) (864 ) (8,776 ) Amounts reclassified from accumulated other comprehensive income 1,263 — (155 ) 1,108 Total Other Comprehensive (Loss) (6,037 ) (3,138 ) (709 ) (9,884 ) Balance at End of Period $ 3,880 $ (5,108 ) $ (2,077 ) $ (3,305 ) The following table presents the amounts reclassified out of each component of accumulated other comprehensive income (loss) for the years ended December 31, 2017 , 2016 , and 2015: Affected Line Item in the Years Ended December 31, (in thousands) 2017 2016 2015 Realized (losses) gains on AFS securities: $ 12,598 $ (551 ) $ 2,110 Non-interest income (4,535 ) 220 (847 ) Tax expense 8,063 (331 ) 1,263 Realized (losses) on cash flow hedging derivatives: (393 ) — — Interest expense (6,629 ) — — Non-interest income — (3,981 ) — Non-interest expense 2,769 1,589 — Tax benefit (4,253 ) (2,392 ) — Realized (losses) on pension plans (217 ) (164 ) (259 ) Non-interest expense 87 73 104 Tax expense (130 ) (91 ) (155 ) Total reclassifications for the period $ 3,680 $ (2,814 ) $ 1,108 Earnings Per Common Share Basic earnings per common share (“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 year. Diluted EPS reflects the potential dilution that could occur if 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 entity. Diluted EPS is computed by dividing net income applicable to common stock by the weighted average number of common shares outstanding for the year, plus an incremental number of common-equivalent shares computed using the treasury stock method. Earnings per common share has been computed based on the following (average diluted shares outstanding is calculated using the treasury stock method): Years Ended December 31, (In thousands, except per share data) 2017 2016 2015 Net income $ 55,247 $ 58,670 $ 49,518 Average number of common shares issued 40,627 32,604 30,074 Less: average number of treasury shares 963 1,116 1,215 Less: average number of unvested stock award shares 437 500 466 Plus: average participating preferred shares 229 — — Average number of basic common shares outstanding 39,456 30,988 28,393 Plus: dilutive effect of unvested stock award shares 202 122 106 Plus: dilutive effect of stock options outstanding 37 57 65 Average number of diluted common shares outstanding 39,695 31,167 28,564 Basic earning per common share $ 1.40 $ 1.89 $ 1.74 Diluted earnings per common share $ 1.39 $ 1.88 $ 1.73 For the year ended 2017, 55 thousand options were anti-dilutive and therefore excluded from the earnings per share calculations. For the year ended 2016, 52 thousand options were anti-dilutive and therefore excluded from the earnings per share calculations. For the year ended 2015, 200 thousand options were anti-dilutive and therefore excluded from the earnings per share calculations.

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 The 2013 Equity Incentive Plan (the “2013 Plan”) permits the granting of a combination of Restricted Stock awards and incentive and non-qualified stock options (“Stock Options”) to employees and directors. A total of 1.0 million shares was authorized under the Plan. Awards may be granted as either Restricted Stock or Stock Options provided that any shares that are granted as Restricted Stock are counted against the share limit set forth as (1) three for every one share of Restricted Stock granted and (2) one for every one share of Stock Option granted. As of year-end 2017, the Company had the ability to grant approximately 383 thousand shares under this plan. The 2011 Equity Incentive Plan (the “2011 Plan”) permits the granting of a combination of Restricted Stock awards and incentive and non-qualified stock options to employees and directors. A total of 1.4 million shares was authorized under the Plan. Awards may be granted as either Restricted Stock or Stock Options provided that any shares that are granted as Restricted Stock are counted against the share limit set forth as (1) three for every one share of Restricted Stock granted and (2) one for every one share of Stock Option granted. As of year-end 2017, the Company had the ability to grant approximately 6 thousand shares under this plan. A summary of activity in the Company’s stock compensation plans is shown below: Non-vested Stock Stock Options Outstanding (Shares in thousands) Number of Shares Weighted- Average Number of Shares Weighted- Average Exercise Price Balance, December 31, 2016 448 $ 26.28 109 $ 15.72 Granted 161 35.84 — — Stock options exercised — — (19 ) 17.74 Stock awards vested (174 ) 25.68 — — Forfeited (17 ) 30.04 — — Expired — — (14 ) 29.35 Balance, December 31, 2017 418 $ 29.68 76 $ 13.59 Stock Awards The total compensation cost for stock awards recognized as expense was $5.3 million , $4.6 million , and $4.7 million , in the years 2017, 2016, and 2015, respectively. The total recognized tax benefit associated with this compensation cost was $2.0 million , $1.8 million , and $1.9 million , respectively. The weighted average fair value of stock awards granted was $35.84 , $26.81 , and $26.66 in 2017, 2016, and 2015, respectively. Stock awards vest over periods up to five years and are valued at the closing price of the stock on the grant date. The total fair value of stock awards vested during 2017, 2016, and 2015 was $4.4 million , $4.4 million , and $3.4 million respectively. The unrecognized stock-based compensation expense related to unvested stock awards was $6.5 million as of year-end 2017. This amount is expected to be recognized over a weighted average period of two years. Option Awards Option awards are granted with an exercise price equal to the market price of the Company’s stock at the date of grant, and vest over periods up to five years. The options grant the holder the right to acquire a share of the Company’s common stock for each option held, and have a contractual life of ten years. As of year-end 2017, the weighted average remaining contractual term for options outstanding is two years. The Company generally issues shares from treasury stock as options are exercised. The fair value of each option grant is estimated on the date of grant using the Black-Scholes option-pricing model. The expected dividend yield and expected term are based on management estimates. The expected volatility is based on historical volatility. The risk-free interest rates for the expected term are based on the U.S. Treasury yield curve in effect at the time of the grant. The Company acquired options in the Beacon transaction in 2012, but did not grant additional options in 2017, 2016, or 2015. The total intrinsic value of options exercised was $362.7 thousand , $879.6 thousand , and $210.0 thousand for the years 2017, 2016, and 2014, respectively. There was no expense pertaining to options vesting in 2017, 2016 or 2015. There was no tax benefit associated with stock option expense in 2017, 2016 or 2015. There was no unrecognized stock-based compensation expense related to unvested stock options as of year-ends 2017, 2016, and 2015.

FAIR VALUE MEASUREMENTS

FAIR VALUE MEASUREMENTS	12 Months Ended
	Dec. 31, 2017
Fair Value Disclosures [Abstract]
FAIR VALUE MEASUREMENTS	FAIR VALUE MEASUREMENTS 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. These valuation methodologies were applied to all of the Company’s financial assets and financial liabilities that are carried at fair value. Recurring Fair Value Measurements of Financial Instruments The following table summarizes assets and liabilities measured at fair value on a recurring basis as of year-end 2017 and 2016 segregated by the level of the valuation inputs within the fair value hierarchy utilized to measure fair value: December 31, 2017 (In thousands) Level 1 Level 2 Level 3 Total Trading security $ — $ — $ 12,277 $ 12,277 Available-for-sale securities: Municipal bonds and obligations — 118,233 — 118,233 Agency collateralized mortgage obligations — 851,158 — 851,158 Agency residential mortgage-backed securities — 216,940 — 216,940 Agency commercial mortgage-backed securities — 62,305 — 62,305 Corporate bonds — 110,721 — 110,721 Trust preferred securities — 11,677 — 11,677 Other bonds and obligations — 9,880 — 9,880 Marketable equity securities 44,851 334 — 45,185 Loans held for sale — 153,620 — 153,620 Derivative assets — 14,049 5,259 19,308 Other assets — — 3,834 3,834 Derivative liabilities 104 15,715 19 15,838 December 31, 2016 (In thousands) Level 1 Level 2 Level 3 Total Trading security $ — $ — $ 13,229 $ 13,229 Available-for-sale securities: Municipal bonds and obligations — 119,816 — 119,816 Agency collateralized mortgage obligations — 651,911 — 651,911 Agency residential mortgage-backed securities — 228,684 — 228,684 Agency commercial mortgage-backed securities — 64,534 — 64,534 Corporate bonds — 56,006 — 56,006 Trust preferred securities — 11,887 — 11,887 Other bonds and obligations — 11,158 — 11,158 Marketable equity securities 62,284 3,257 — 65,541 Loans held for sale — 120,673 — 120,673 Derivative assets 622 16,157 4,838 21,617 Other assets — — 798 798 Derivative liabilities — 24,420 — 24,420 There were no transfers between Level 1, 2, and 3 during the year ended December 31, 2017. During the year ended December 31, 2016, the Company had one transfer of $708 thousand in marketable equity securities from Level 3 to Level 2 based on a change in valuation technique driven by the availability of market data. There were no transfers between Level 1, 2, and 3 during the year ended December 31, 2015. Trading Security at Fair Value. The Company holds one security designated as a trading security. It is a tax advantaged economic development bond issued to the Company by a local nonprofit which provides wellness and health programs. The determination of the fair value for this security is determined based on a discounted cash flow methodology. Certain inputs to the fair value calculation are unobservable and there is little to no market activity in the security; therefore, the security meets the definition of a Level 3 security. The discount rate used in the valuation of the security is sensitive to movements in the 3-month LIBOR rate. Securities Available for Sale . AFS securities classified as Level 1 consist of publicly-traded equity securities for which the fair values can be obtained through quoted market prices in active exchange markets. AFS securities classified as Level 2 include most of the Company’s debt securities. The pricing on Level 2 was primarily sourced from third party pricing services, overseen by management, and is based on models that consider standard input factors such as dealer quotes, market spreads, cash flows, the U.S. Treasury yield curve, live trading levels, trade execution data, market consensus prepayment speeds, credit information and the bond’s terms and condition, among other things. Loans held for sale. The Company elected the fair value option for all loans originated for sale (HFS) that were originated for sale on or after May 1, 2012. Loans HFS are classified as Level 2 as the fair value is based on input factors such as quoted prices for similar loans in active markets. Aggregate Aggregate Aggregate Fair Value December 31, 2017 (In thousands) Loans Held for Sale $ 153,620 $ 149,022 $ 4,598 Aggregate Aggregate Aggregate Fair Value December 31, 2016 (In thousands) Loans Held for Sale $ 120,673 $ 118,178 $ 2,495 The changes in fair value of loans held for sale for years ended December 31, 2017 and 2016 were gains of $2.1 million and $2.2 million , respectively. The changes in fair value are included in mortgage banking income in the Consolidated Statements of Income. In 2017, originations of loans held for sale totaled $2.4 billion and sales of loans originated as held for sale totaled $2.3 billion . Interest Rate Swaps. The valuation of the Company’s interest rate swaps is obtained from a third-party pricing service and is determined using a discounted cash flow analysis on the expected cash flows of each derivative. The pricing analysis is based on observable inputs for the contractual terms of the derivatives, including the period to maturity and interest rate curves. The Company incorporates credit valuation adjustments to appropriately reflect both its own nonperformance risk and the respective counterparty’s nonperformance risk in the fair value measurements. In adjusting the fair value of its derivative contracts for the effect of nonperformance risk, the Company has considered the impact of netting and any applicable credit enhancements, such as collateral postings. Although the Company has determined that the majority of the inputs used to value its interest rate derivatives fall within Level 2 of the fair value hierarchy, the credit valuation adjustments associated with its derivatives utilize Level 3 inputs, such as estimates of current credit spreads to evaluate the likelihood of default by itself and its counterparties. However, as of year-end 2017, 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. As a result, the Company has determined that its derivative valuations in their entirety are classified in Level 2 of the fair value hierarchy. Commitments to Lend. The Company enters into commitments to lend for residential mortgage loans intended for sale, which commit the Company to lend funds to a potential borrower at a certain interest rate and within a specified period of time. The estimated fair value of commitments to originate residential mortgage loans for sale is based on quoted prices for similar loans in active markets. However, this value is adjusted by a factor which considers the likelihood that the loan commitment will ultimately close, and by the non-refundable costs of originating the loan. The closing ratio is derived from the Bank’s internal data and is adjusted using significant management judgment. The costs to originate are primarily based on the Company’s internal commission rates that are not observable. As such, these commitments to lend are classified as Level 3 measurements. Forward Sale Commitments . The Company utilizes forward sale commitments as economic hedges against potential changes in the values of the commitments to lend and loans originated for sale. To be announced (TBA) mortgage-backed securities forward commitment sales are used as hedging instruments, are classified as Level 1, and consist of publicly-traded debt securities for which identical fair values can be obtained through quoted market prices in active exchange markets. The fair values of the Company’s best efforts and mandatory delivery loan sale commitments are determined similarly to the commitments to lend using quoted prices in the market place that are observable. However, costs to originate and closing ratios included in the calculation are internally generated and are based on management’s judgment and prior experience, which are considered factors that are not observable. As such, best efforts and mandatory forward sale commitments are classified as Level 3 measurements. Capitalized Servicing Rights. The Company accounts for certain capitalized servicing rights at fair value in its Consolidated Financial Statements, as the Company is permitted to elect the fair value option for each specific instrument. A loan servicing right asset represents the amount by which the present value of the estimated future net cash flows to be received from servicing loans exceed adequate compensation for performing the servicing. The fair value of servicing rights is estimated using a present value cash flow model. The most important assumptions used in the valuation model are the anticipated rate of the loan prepayments and discount rates. Although some assumptions in determining fair value are based on standards used by market participants, some are based on unobservable inputs and therefore are classified in Level 3 of the valuation hierarchy. The table below presents the changes in Level 3 assets that were measured at fair value on a recurring basis at year-end 2017 and 2016 : Assets (Liabilities) (In thousands) Trading Securities Available for Sale Commitments to Lend Forward Capitalized Servicing Rights Balance as of December 31, 2015 $ 14,189 $ 708 $ 323 $ 9 $ — Amounts acquired from First Choice Bank — — 3,900 — 696 Unrealized (loss) gain, net recognized in other non-interest income (362 ) — 13,563 91 102 Unrealized gain included in accumulated other comprehensive loss — — — — — Transfers to Level 2 — (708 ) — — — Paydown of trading security (598 ) — — — — Transfers to loans held for sale — — (13,048 ) — — Balance as of December 31, 2016 $ 13,229 $ — $ 4,738 $ 100 $ 798 Unrealized (loss) gain, net recognized in other non-interest income (320 ) — 63,894 (81 ) (221 ) Unrealized gain included in accumulated other comprehensive loss — — — — — Transfers to Level 2 — — — — — Paydown of trading security (632 ) — — — — Transfers to loans held for sale — — (63,373 ) — — Additions to servicing rights — — — — 3,257 Balance as of December 31, 2017 $ 12,277 $ — $ 5,259 $ 19 $ 3,834 Unrealized gains (losses) relating to instruments still held at December 31, 2017 $ 1,522 $ — $ 5,259 $ 19 $ (221 ) Unrealized gains relating to instruments still held at December 31, 2016 $ 1,843 $ — $ 4,738 $ 100 $ 102 Quantitative information about the significant unobservable inputs within Level 3 recurring assets/(liabilities) as of December 31, 2017 and 2016 are as follows: Fair Value Significant Unobservable Input Value (In thousands) December 31, 2017 Valuation Techniques Unobservable Inputs Assets Trading Security $ 12,277 Discounted Cash Flow Discount Rate 2.74 % Forward Commitments 19 Historical Trend Closing Ratio 81.53 % Pricing Model Origination Costs, per loan $ 3,692 Commitments to Lend 5,259 Historical Trend Closing Ratio 81.53 % Pricing Model Origination Costs, per loan $ 3,692 Capitalized Servicing Rights 3,834 Discounted cash flow Constant prepayment rate (CPR) 10.00 % Discount rate 10.95 % Total $ 21,389 Fair Value Significant (In thousands) December 31, 2016 Valuation Techniques Unobservable Inputs Assets Trading Security $ 13,229 Discounted Cash Flow Discount Rate 2.62 % Forward Commitments 100 Historical Trend Closing Ratio 80.36 % Commitments to Lend 4,738 Pricing Model Origination Costs, per loan $ 3.692 Historical Trend Closing Ratio 80.36 % Capitalized Servicing Rights 798 Pricing Model Origination Costs, per loan $ 3.692 Discounted cash flow Constant prepayment rate (CPR) 10.40 % Discount rate 11.00 % Total $ 18,865 Non-Recurring Fair Value Measurements The Company is required, on a non-recurring basis, to adjust the carrying value or provide valuation allowances for certain assets using fair value measurements in accordance with GAAP. The following is a summary of applicable non-recurring fair value measurements. There are no liabilities measured on a non-recurring basis. December 31, 2017 Fair Value Measurements as of December 31, 2017 (In thousands) Level 3 Level 3 Inputs Assets Impaired loans $ 23,853 December 2017 Capitalized servicing rights 12,527 December 2017 Other real estate owned — — Total $ 36,380 December 31, 2016 Fair Value Measurements as of December 31, 2016 (In thousands) Level 3 Level 3 Assets Impaired loans $ 17,761 December 2016 Capitalized servicing rights 10,726 December 2016 Other real estate owned 151 Feb. 2016 - July 2016 Total $ 28,638 Quantitative information about the significant unobservable inputs within Level 3 non-recurring assets as of December 31, 2017 and 2016 are as follows: (in thousands) December 31, 2017 Valuation Techniques Unobservable Inputs Range (Weighted Average) (a) Assets Impaired loans $ 23,853 Fair value of collateral Loss severity 38.72% to 0.21% (3.40%) Appraised value $10.9 to $5967 ($2,197) Capitalized servicing rights 12,527 Discounted cash flow Constant prepayment rate (CPR) 7.78% to 12.78% (10.38%) Discount rate 10.00% to 13.28% (11.72%) Other real estate owned — Fair value of collateral Appraised value — Total Assets $ 36,380 (a) Where dollar amounts are disclosed, the amounts represent the lowest and highest fair value of the respective assets in the population except for adjustments for market/property conditions, which represents the range of adjustments to individuals properties. (in thousands) December 31, 2016 Valuation Techniques Unobservable Inputs Range (Weighted Average) (a) Assets Impaired loans $ 17,761 Fair value of collateral Loss severity 0% to 88.70% (9.73%) Appraised value $0 to $2,192 ($1,026) Capitalized servicing rights 10,726 Discounted cash flow Constant prepayment rate (CPR) 7.35% to 14.28% (10.44%) Discount rate 10.00% to 14.00% (11.77%) Other real estate owned 151 Fair value of collateral Appraised value $101 to $129 ($122) Total Assets $ 28,638 (a) Where dollar amounts are disclosed, the amounts represent the lowest and highest fair value of the respective assets in the population except for adjustments for market/property conditions, which represents the range of adjustments to individuals properties. There were no Level 1 or Level 2 nonrecurring fair value measurements for year-end 2017 and 2016 . Impaired Loans. Loans are generally not recorded at fair value on a recurring basis. Periodically, the Company records non-recurring adjustments to the carrying value of loans based on fair value measurements for partial charge-offs of the uncollectible portions of those loans. Non-recurring adjustments can also include certain impairment amounts for collateral-dependent loans calculated when establishing the allowance for credit losses. Such amounts are generally based on the fair value of the underlying collateral supporting the loan and, as a result, the carrying value of the loan less the calculated valuation does not necessarily represent the fair value of the loan. Real estate collateral is typically valued using appraisals or other indications of value based on recent comparable sales of similar properties or assumptions generally observable in the marketplace. However, the choice of observable data is subject to significant judgment, and there are often adjustments based on judgment in order to make observable data comparable and to consider the impact of time, the condition of properties, interest rates, and other market factors on current values. Additionally, commercial real estate appraisals frequently involve discounting of projected cash flows, which relies inherently on unobservable data. Therefore, real estate collateral related nonrecurring fair value measurement adjustments have generally been classified as Level 3. Estimates of fair value for other collateral that supports commercial loans are generally based on assumptions not observable in the marketplace and therefore such valuations have been classified as Level 3. Capitalized loan servicing rights . A loan servicing right asset represents the amount by which the present value of the estimated future net cash flows to be received from servicing loans exceed adequate compensation for performing the servicing. The fair value of servicing rights is estimated using a present value cash flow model. The most important assumptions used in the valuation model are the anticipated rate of the loan prepayments and discount rates. Adjustments are only recorded when the discounted cash flows derived from the valuation model are less than the carrying value of the asset. Although some assumptions in determining fair value are based on standards used by market participants, some are based on unobservable inputs and therefore are classified in Level 3 of the valuation hierarchy. Other real estate owned (“OREO”). OREO results from the foreclosure process on residential or commercial loans issued by the Bank. Upon assuming the real estate, the Company records the property at the fair value of the asset less the estimated sales costs. Thereafter, OREO properties are recorded at the lower of cost or fair value less the estimated sales costs. OREO fair values are primarily determined based on Level 3 data including sales comparables and appraisals. Summary of Estimated Fair Values of Financial Instruments The estimated fair values, and related carrying amounts, of the Company’s financial instruments follow. Certain financial instruments and all non-financial instruments are excluded from disclosure requirements. Accordingly, the aggregate fair value amounts presented herein may not necessarily represent the underlying fair value of the Company. December 31, 2017 Carrying Fair (In thousands) Level 1 Level 2 Level 3 Financial Assets Cash and cash equivalents $ 248,763 $ 248,763 $ 248,763 $ — $ — Trading security 12,277 12,277 — — 12,277 Securities available for sale 1,426,099 1,426,099 44,850 1,381,249 — Securities held to maturity 397,103 405,276 — 371,458 33,818 FHLB stock and restricted equity securities 63,085 N/A — N/A — Net loans 8,247,504 8,422,034 — — 8,422,034 Loans held for sale 153,620 153,620 — 153,620 — Accrued interest receivable 33,739 33,739 — 33,739 — Derivative assets 19,308 19,308 — 14,049 5,259 Assets held for sale 1,392 1,392 — 1,392 — Financial Liabilities Total deposits 8,749,530 8,731,527 — 8,731,527 — Short-term debt 667,300 667,246 — 667,246 — Long-term FHLB advances 380,436 378,766 — 378,766 — Subordinated notes 89,339 97,414 — 97,414 — Derivative liabilities 15,838 15,838 104 15,715 19 December 31, 2016 Carrying Fair (In thousands) Level 1 Level 2 Level 3 Financial Assets Cash and cash equivalents $ 113,075 $ 113,075 $ 113,075 $ — $ — Trading security 13,229 13,229 — — 13,229 Securities available for sale 1,209,537 1,209,537 62,284 1,147,253 — Securities held to maturity 334,368 337,680 — 300,806 36,874 FHLB stock and restricted equity securities 71,112 N/A — N/A — Net loans 6,505,789 6,532,745 — — 6,532,745 Loans held for sale 120,673 120,673 — 120,673 — Accrued interest receivable 26,113 26,113 — 26,113 — Derivative assets 21,617 21,617 622 16,157 4,838 Assets held for sale 322 322 — 322 — Financial Liabilities Total deposits 6,622,092 6,624,108 — 6,624,108 — Short-term debt 1,082,044 1,081,996 — 1,081,996 — Long-term FHLB advances 142,792 143,151 — 143,151 — Subordinated notes 89,161 96,973 — 96,973 — Derivative liabilities 24,420 24,420 — 24,420 — Other than as discussed above, the following methods and assumptions were used by management to estimate the fair value of significant classes of financial instruments for which it is practicable to estimate that value. Cash and cash equivalents. Carrying value is assumed to represent fair value for cash and cash equivalents that have original maturities of ninety days or less. FHLB stock and restricted equity securities. It is not practical to determine fair value due to the restricted nature of the security. Loans, net. The carrying value of the loans in the loan portfolio is based on cash flows discounted over their respective loan origination rates. The origination rates are adjusted for substandard and special mention loans to factor the impact of declines in the loan’s credit standing. The fair value of the loans is estimated by discounting future cash flows using the current interest rates at which similar loans with similar terms would be made to borrowers of similar credit quality. The methodology utilized to determine fair value does not represent exit price. Accrued interest receivable. Carrying value approximates fair value. Deposits. The fair value of demand, non-interest bearing 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. Borrowed funds. The fair value of borrowed funds is estimated by discounting the future cash flows using market rates for similar borrowings. Such funds include all categories of debt and debentures in the table above. Subordinated borrowings. The Company utilizes a pricing service along with internal models to estimate the valuation of its junior subordinated debentures. The junior subordinated debentures re-price every ninety days. Off-balance-sheet financial instruments. Off-balance-sheet financial instruments include standby letters of credit and other financial guarantees and commitments considered immaterial to the Company’s financial statements.

CONDENSED FINANCIAL STATEMENTS

CONDENSED FINANCIAL STATEMENTS OF PARENT COMPANY	12 Months Ended
	Dec. 31, 2017
Condensed Financial Information of Parent Company Only Disclosure [Abstract]
CONDENSED FINANCIAL STATEMENTS OF PARENT COMPANY	CONDENSED FINANCIAL STATEMENTS OF PARENT COMPANY Condensed financial information pertaining only to the Parent, Berkshire Hills Bancorp, is as follows. Investment in subsidiaries at December 31, 2017 includes $35 million of intercompany subordinated notes. CONDENSED BALANCE SHEETS December 31, (In thousands) 2017 2016 Assets Cash due from Berkshire Bank $ 83,380 $ 43,018 Investment in subsidiaries 1,470,859 1,127,706 Securities available for sale, at fair value 21,827 23,651 Other assets 12,138 1,372 Total assets $ 1,588,204 $ 1,195,747 Liabilities and Shareholders’ Equity Short term debt $ — $ 10,000 Subordinated notes 89,339 89,161 Accrued expenses 2,601 3,288 Shareholders’ equity 1,496,264 1,093,298 Total liabilities and shareholders’ equity $ 1,588,204 $ 1,195,747 CONDENSED STATEMENTS OF INCOME Years Ended December 31, (In thousands) 2017 2016 2015 Income: Dividends from subsidiaries $ 39,000 $ 33,000 $ 34,000 Other 5,864 4,072 2,763 Total income 44,864 37,072 36,763 Interest expense 5,338 5,743 5,674 Non-interest expenses 6,042 3,740 3,670 Total expense 11,380 9,483 9,344 Income before income taxes and equity in undistributed income of subsidiaries 33,484 27,589 27,419 Income tax benefit (1,783 ) (2,123 ) (2,518 ) Income before equity in undistributed income of subsidiaries 35,267 29,712 29,937 Equity in undistributed income of subsidiaries 19,980 28,958 19,581 Net income 55,247 58,670 49,518 Preferred stock dividend 219 — — Income available to common shareholders $ 55,028 $ 58,670 $ 49,518 CONDENSED STATEMENTS OF CASH FLOWS Years Ended December 31, (In thousands) 2017 2016 2015 Cash flows from operating activities: Net income $ 55,247 $ 58,670 $ 49,518 Adjustments to reconcile net income to net cash (used) provided by operating activities: Equity in undistributed income of subsidiaries (19,980 ) (28,958 ) (19,581 ) Other, net (7,964 ) 1,988 10,904 Net cash provided by operating activities 27,303 31,700 40,841 Cash flows from investing activities: Advances to subsidiaries (100,000 ) — — Acquisitions, net of cash paid — — (3,293 ) Purchase of securities (1,057 ) (18,016 ) (18 ) Sale of securities 2,101 — — Other, net 1,508 9,728 — Net cash (used) in investing activities (97,448 ) (8,288 ) (3,311 ) Cash flows from financing activities: Proceed from issuance of short term debt — 9,349 — Repayment of short term debt (9,822 ) — (9,935 ) Net proceeds from common stock 153,313 3,712 — Net proceeds from preferred stock — — — Net proceeds from reissuance of treasury stock — — 240 Payment to repurchase common stock — (4,632 ) (550 ) Common stock cash dividends paid (33,022 ) (24,916 ) (21,903 ) Preferred stock cash dividends paid (219 ) — — Other, net 257 11 167 Net cash provided provided/(used) by financing activities 110,507 (16,476 ) (31,981 ) Net change in cash and cash equivalents 40,362 6,936 5,549 Cash and cash equivalents at beginning of year 43,018 36,082 30,533 Cash and cash equivalents at end of year $ 83,380 $ 43,018 $ 36,082

QUARTERLY DATA (UNAUDITED)

QUARTERLY DATA (UNAUDITED)	12 Months Ended
	Dec. 31, 2017
Quarterly Financial Information Disclosure [Abstract]
QUARTERLY DATA (UNAUDITED)	QUARTERLY DATA (UNAUDITED) Quarterly results of operations were as follows: 2017 2016 (In thousands, except per share data) Fourth Quarter Third Quarter Second Quarter First Quarter Fourth Quarter Third Quarter Second Quarter First Quarter Interest and dividend income $ 105,823 $ 89,060 $ 84,666 $ 80,709 $ 72,434 $ 70,511 $ 69,018 $ 68,476 Interest expense 19,457 17,062 15,121 13,823 13,276 12,540 11,577 10,779 Net interest income 86,366 71,998 69,545 66,886 59,158 57,971 57,441 57,697 Non-interest income 29,298 28,836 32,798 34,757 16,725 18,941 14,555 15,630 Total revenue 115,664 100,834 102,343 101,643 75,883 76,912 71,996 73,327 Provision for loan losses 6,141 4,900 4,889 5,095 4,100 4,734 4,522 4,006 Non-interest expense 90,041 65,820 69,523 74,326 61,090 48,844 46,268 47,100 Income before income taxes 19,482 30,114 27,931 22,222 10,693 23,334 21,206 22,221 Income tax expense (1) 22,292 7,211 8,237 6,762 362 6,953 5,249 6,220 Net (loss)/income $ (2,810 ) $ 22,903 $ 19,694 $ 15,460 $ 10,331 $ 16,381 $ 15,957 $ 16,001 Basic (loss)/earnings per common share $ (0.06 ) $ 0.57 $ 0.53 $ 0.44 $ 0.32 $ 0.53 $ 0.52 $ 0.52 Diluted (loss)/earnings per share $ (0.06 ) $ 0.57 $ 0.53 $ 0.44 $ 0.32 $ 0.53 $ 0.52 $ 0.52 Weighted average common shares outstanding: Basic 45,122 39,984 37,324 35,280 32,185 30,621 30,605 30,511 Diluted 45,122 40,145 37,474 35,452 32,381 30,811 30,765 30,688 (1) 2017 income tax expense includes $18.1 million charge to re-measure the net deferred tax asset at December 31, 2017 pursuant to the reduction in the corporate income tax rate from 35% to 21%, effective January 1, 2018, per the Tax Cuts and Jobs Act enacted on December 22, 2017.

NET INTEREST INCOME AFTER PROVI

NET INTEREST INCOME AFTER PROVISION FOR LOAN LOSSES	12 Months Ended
	Dec. 31, 2017
Banking and Thrift, Interest [Abstract]
NET INTEREST INCOME AFTER PROVISION FOR LOAN LOSSES	NET INTEREST INCOME AFTER PROVISION FOR LOAN LOSSES Presented below is net interest income after provision for loan losses for the three years ended 2017, 2016, and 2015, respectively: Years Ended December 31, (In thousands) 2017 2016 2015 Net interest income $ 294,795 $ 232,267 $ 213,849 Provision for loan losses 21,025 17,362 16,726 Net interest income after provision for loan losses 273,770 214,905 197,123 Total non-interest income 125,689 65,851 54,288 Total non-interest expense 299,710 203,302 196,829 Income from continuing operations before income taxes 99,749 77,454 54,582 Income tax expense 44,502 18,784 5,064 Net income $ 55,247 $ 58,670 $ 49,518

SUMMARY OF SIGNIFICANT ACCOUN33

SUMMARY OF SIGNIFICANT ACCOUNTING POLICES (Policies)	12 Months Ended
	Dec. 31, 2017
Accounting Policies [Abstract]
Basis of Presentation and Consolidation	Basis of Presentation and Consolidation The consolidated financial statements (the “financial statements”) of Berkshire Hills Bancorp, Inc. and its subsidiaries (the “Company” or “Berkshire”) have been prepared in conformity with accounting principles generally accepted in the United States of America (“GAAP”). The Company is a Delaware corporation and the holding company for Berkshire Bank (the “Bank”), a Massachusetts-chartered trust company headquartered in Boston, Mass. These financial statements include the accounts of the Company, its wholly-owned subsidiaries and the Bank’s consolidated subsidiaries. In consolidation, all significant intercompany accounts and transactions are eliminated. The results of operations of companies or assets acquired are included only from the dates of acquisition. All material wholly-owned and majority-owned subsidiaries are consolidated unless GAAP requires otherwise.
Reclassifications	Reclassifications Certain items in prior financial statements have been reclassified to conform to the current presentation. The Company has evaluated subsequent events for potential recognition and/or disclosure through the date these consolidated financial statements were issued.
Use of Estimates	Use of Estimates The preparation of 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 liabilities at the date of the financial statements. Actual results could differ from those estimates.
Business Combinations	Business Combinations Business combinations are accounted for using the acquisition method of accounting. Under this method, the accounts of an acquired entity are included with the acquirer’s accounts as of the date of acquisition with any excess of purchase price over the fair value of the net assets acquired (including identifiable intangibles) capitalized as goodwill. To consummate an acquisition, the Company will typically issue common stock and/or pay cash, depending on the terms of the acquisition agreement. The value of common shares issued is determined based upon the market price of the stock as of the closing of the acquisition.
Cash and Cash equivalents	Cash and Cash equivalents Cash and cash equivalents include cash, balances due from banks, and short-term investments, all of which had an original maturity within 90 days. Due to the nature of cash and cash equivalents and the near term maturity, the Company estimated that the carrying amount of such instruments approximated fair value. The nature of the Bank’s business requires that it maintain amounts due from banks which at times, may exceed federally insured limits. The Bank has not experienced any losses on such amounts and all amounts are maintained with well-capitalized institutions.
Trading Security	Trading Security The Company accounts for a tax advantaged economic development bond originated in 2008 at fair value, in accordance with Financial Accounting Standards Board’s (“FASB”) Accounting Standards Codification (“ASC”) 320. The bond has been designated as a trading account security and is recorded at fair value, with changes in unrealized gains and losses recorded through earnings each period as part of non-interest income.
Securities	Securities Debt securities that management has the intent and ability to hold to maturity are classified as held to maturity and carried at amortized cost. All other securities, including equity securities with readily determinable fair values, are classified as available for sale and carried at fair value, with unrealized gains and losses reported as a component of other net comprehensive income. Management determines the appropriate classification of securities at the time of purchase. Restricted equity securities, such as stock in the Federal Home Loan Bank of Boston (“FHLBB”) are carried at cost. There are no quoted market prices for the Company’s restricted equity securities. The Bank is a member of the FHLBB, which requires that members maintain an investment in FHLBB stock, which may be redeemed based on certain conditions. The Bank reviews for impairment based on the ultimate recoverability of the cost bases in the FHLBB stock. Purchase premiums and discounts are recognized in interest income using the interest method over the terms of the securities. Gains and losses on the sale of securities are recorded on the trade date and are determined using the specific identification method. The Company evaluates debt and equity securities within the Company’s available for sale and held to maturity portfolios for other-than-temporary impairment (“OTTI”), at least quarterly. If the fair value of a debt security is below the amortized cost basis of the security, OTTI is required to be recognized if any of the following are met: (1) the Company intends to sell the security; (2) it is “more likely than not” that the Company will be required to sell the security before recovery of its amortized cost basis; or (3) the present value of expected cash flows is not sufficient to recover the entire amortized cost basis. For all impaired debt securities that the Company intends to sell, or more likely than not will be required to sell, the full amount of the depreciation is recognized as OTTI through earnings. Credit-related OTTI for all other impaired debt securities is recognized through earnings. Non-credit related OTTI for such debt securities is recognized in other comprehensive income, net of applicable taxes. In evaluating its marketable equity securities portfolios for OTTI, the Company considers its intent and ability to hold an equity security to recovery of its cost basis in addition to various other factors, including the length of time and the extent to which the fair value has been less than cost and the financial condition and near term prospects of the issuer. Any OTTI on marketable equity securities is recognized immediately through earnings.
Loans Held for Sale	Loans Held for Sale Loans originated with the intent to be sold in the secondary market are accounted for under the fair value option. Non-refundable fees and direct loan origination costs related to residential mortgage loans held for sale are recognized in non-interest income or non-interest expense as earned or incurred. Fair value is primarily determined based on quoted prices for similar loans in active markets. Gains and losses on sales of residential mortgage loans (sales proceeds minus carrying value) are recorded in non-interest income. Loans that were previously held for investment that the Company has an active plan to sell are transferred to loans held for sale at the lower of cost or market (fair value). The market price is primarily determined based on quoted prices for similar loans in active markets or agreed upon sales prices. Gains are recorded in non-interest income at sale to the extent that the sale price of the loan exceeds carrying value. Any reduction in the loan’s value, prior to being transferred to loans held for sale, is reflected as a charge-off of the recorded investment in the loan resulting in a new cost basis, with a corresponding reduction in the allowance for loan losses. Further changes in the fair value of the loan are recognized in non-interest income or expense, accordingly.
Loans	Loans Loans are reported at their outstanding unpaid principal balances adjusted for charge-offs, the allowance for loan losses, the unamortized balance of any deferred fees or costs on originated loans and the unamortized balance of any premiums or discounts on loans purchased or acquired through mergers. Interest income is accrued on the unpaid principal balance. Interest income includes net accretion or amortization of deferred fees or costs and of premiums or discounts. Direct loan origination costs, net of any origination fees, in addition to premiums and discounts on loans, are deferred and recognized as an adjustment of the related loan yield using the interest method. Interest on loans, excluding automobile loans, is generally not accrued on loans which are ninety days or more past due unless the loan is well-secured and in the process of collection. Past due status is based on contractual terms of the loan. Automobile loans generally continue accruing until one hundred and twenty days delinquent, at which time they are charged off. All interest accrued but not collected for loans that are placed on non-accrual or charged-off is reversed against interest income, except for certain loans designated as well-secured. The interest on non-accrual loans is accounted for on the cash-basis or cost-recovery method, until qualifying for return to accrual. All payments received on non-accrual loans are applied against the principal balance of the loan. Loans are returned to accrual status when all the principal and interest amounts contractually due are brought current and future payments are reasonably assured.
Acquired Loans	Acquired Loans Loans that the Company acquired in acquisitions are initially recorded at fair value with no carryover of the related allowance for credit losses. Determining the fair value of the loans involves estimating the amount and timing of principal and interest cash flows initially expected to be collected on the loans and discounting those cash flows at an appropriate market rate of interest. For loans that meet the criteria stipulated in ASC 310-30, “ Loans and Debt Securities Acquired with Deteriorated Credit Quality, ” the Company recognizes the accretable yield, which is defined as the excess of all cash flows expected at acquisition over the initial fair value of the loan, as interest income on a level-yield basis over the expected remaining life of the loan. The excess of the loan’s contractually required payments over the cash flows expected to be collected is the nonaccretable difference. The nonaccretable difference is not recognized as an adjustment of yield, a loss accrual, or a valuation allowance. For ASC 310-30 loans, the expected cash flows reflect anticipated prepayments, determined on a loan by loan basis according to the anticipated collection plan of these loans. The expected prepayments used to determine the accretable yield are consistent between the cash flows expected to be collected and projections of contractual cash flows so as to not affect the nonaccretable difference. For ASC 310-30 loans, prepayments result in the recognition of the nonaccretable balance as current period yield. Changes in prepayment assumptions may change the amount of interest income and principal expected to be collected. Interest income is also net of recoveries recorded on acquired impaired loans. ASC310-30 loans that have similar risk characteristics, primarily credit risk, collateral type and interest rate risk, and are homogenous in size, are pooled and accounted for as a single asset with a single composite interest rate and an aggregate expectation of cash flows. ASC 310-30 loans that cannot be aggregated into a pool are accounted for individually. After we acquire loans determined to be accounted for under ASC 310-30, actual cash collections are monitored to determine if they conform to management’s expectations. Revised cash flow expectations are prepared each quarter. A decrease in expected cash flows in subsequent periods may indicate impairment and would require us to establish an allowance for loan and lease losses (“ALLL”) by recording a charge to the provision for loan and lease losses. An increase in expected cash flows in subsequent periods initially reduces any previously established ALLL by the increase in the present value of cash flows expected to be collected, and requires us to recalculate the amount of accretable yield for the ASC 310-30 loan or pool. The adjustment of accretable yield due to an increase in expected cash flows is accounted for as a change in estimate. The additional cash flows expected to be collected are reclassified from the nonaccretable difference to the accretable yield, and the amount of periodic accretion is adjusted accordingly over the remaining life of the ASC 310-30 loan or pool. An ASC 310-30 loan may be derecognized either through receipt of payment (in full or in part) from the borrower, the sale of the loan to a third party, foreclosure of the collateral, or charge-off. If one of these events occurs, the loan is removed from the loan pool, or derecognized if it is accounted for as an individual loan. ASC 310-30 loans subject to modification are not removed from an ASC 310-30 pool even if those loans would otherwise be deemed troubled debt restructurings (“TDRs”) since the pool, and not the individual loan, represents the unit of account. Individually accounted for ASC 310-30 loans that are modified in a TDR are no longer classified as ASC 310-30 loans and are subject to TDR recognition. Acquired loans that met the criteria for nonaccrual of interest prior to the acquisition are considered performing upon acquisition, regardless of whether the customer is contractually delinquent, if the Company can reasonably estimate the timing and amount of the expected cash flows on such loans and if the Company expects to fully collect the new carrying value of the loans. As such, the Company may no longer consider the loan to be nonaccrual or nonperforming and may accrue interest on these loans, including the impact of any accretable yield. The Company has determined that the Company can reasonably estimate future cash flows on the Company’s current portfolio of acquired loans that are past due 90 days or more and on which the Company is accruing interest and the Company expects to fully collect the carrying value of the loans.
Allowance for Loan Losses	Allowance for Loan Losses The allowance for loan losses is established based upon the level of estimated probable incurred losses in the current loan portfolio. Loan losses are charged against the allowance when management believes the collectability of a loan balance is doubtful. Subsequent recoveries, if any, are credited to the allowance. The allowance for loan losses includes allowance allocations calculated in accordance with ASC 310, “Receivables,” and allowance allocations calculated in accordance with ASC 450, “Contingencies.” The allowance for loan losses is allocated to loan types using both a formula-based approach applied to groups of loans and an analysis of certain individual loans for impairment. The formula-based approach emphasizes loss factors derived from actual historical and industry portfolio loss rates, which are combined with an assessment of certain qualitative factors to determine the allowance amounts allocated to the various loan categories. Allowance amounts are based on an estimate of historical average annual percentage rate of loan loss for each loan segment, a temporal estimate of the incurred loss emergence and confirmation period for each loan category, and certain qualitative risk factors considered in the computation of the allowance for loan losses. Qualitative risk factors impacting the inherent risk of loss within the portfolio include the following: • National and local economic conditions, regulatory/legislative changes, or other competitive factors affecting the collectability of the portfolio • Trends in underwriting characteristics, composition of the portfolio, and/or asset quality • Changes in underwriting standards and/or collection, charge off, recovery, and account management practice • The existence and effect of any concentrations of credit Risk characteristics relevant to each portfolio segment are as follows: Commercial real estate — Loans in this segment are primarily owner-occupied or income-producing properties throughout New England and Northeastern New York. The underlying cash flows generated by the properties are adversely impacted by a downturn in the economy, which in turn, will have an effect on the credit quality in this segment. Management monitors the cash flows of these loans. In addition, construction loans in this segment primarily include real estate development loans for which payment is derived from sale of the property or long term financing at completion. Credit risk is affected by cost overruns, time to sell at an adequate price, and market conditions Commercial and industrial loans — Loans in this segment are made to businesses and are generally secured by assets of the business. Repayment is expected from the cash flows of the business. Loans in this segment include asset based loans which generally have no scheduled repayment and which are closely monitored against formula based collateral advance ratios. A weakened economy, and resultant decreased consumer spending, will have an effect on the credit quality in this segment. Residential mortgage — All loans in this segment are collateralized by residential real estate and repayment is dependent on the credit quality of the individual borrower. The overall health of the economy, including unemployment rates and housing prices, will have an effect on the credit quality in this segment. Consumer loans — Loans in this segment are primarily home equity lines of credit and second mortgages, together with automobile loans and other consumer loans. The overall health of the economy, including unemployment rates and housing prices, will have an effect on the credit quality in this segment. The Company utilizes a blend of historical and industry portfolio loss rates for commercial real estate and commercial and industrial loans that are assessed by internal risk rating. Historical loss rates for residential mortgages, home equity and other consumer loans are not risk graded but are assessed based on the total of each loan segment. This approach incorporates qualitative adjustments based upon management’s assessment of various market and portfolio specific risk factors into its formula-based estimate. Due to the imprecise nature of the loan loss estimation process and ever changing conditions, the qualitative risk attributes may not adequately capture amounts of incurred loss in the formula-based loan loss components used to determine allocations in the Company’s analysis of the adequacy of the allowance for loan losses. The Company evaluates certain loans individually for specific impairment. Large groups of small balance homogeneous loans such as the residential mortgage, home equity, and other consumer portfolios are collectively evaluated for impairment. A loan is considered impaired when, based on current information and events, it is probable that the Company will be unable to collect the scheduled payments of principal or interest when due according to the contractual terms of the loan agreement. Factors considered by management in determining impairment include payment status, collateral value, and the probability of collecting scheduled principal and interest payments when due. Loans that experience insignificant payment delays and payment shortfalls generally are not classified as impaired. Loans are selected for evaluation based upon a change in internal risk rating, occurrence of delinquency, loan classification, or non-accrual status. The evaluation of certain loans individually for specific impairment includes non-accrual loans over a threshold and loans that were determined to be Troubled Debt Restructurings (“TDRs”). A specific allowance amount is allocated to an individual loan when such loan has been deemed impaired and when the amount of the probable loss is able to be estimated. Estimates of loss may be determined by the present value of anticipated future cash flows or the loan’s observable fair market value, or the fair value of the collateral less costs to sell, if the loan is collateral dependent. However, for collateral dependent loans, the amount of the recorded investment in a loan that exceeds the fair value of the collateral is charged-off against the allowance for loan losses in lieu of an allocation of a specific allowance amount when such an amount has been identified definitively as uncollectible. Regarding acquired loans, the Company subjects loans that do not meet the ASC 310-30 criteria to ASC 450-20 by collectively evaluating these loans for an allowance for loan loss. The Company applies a methodology similar to the methodology prescribed for business activities loans, which includes the application of environmental factors to each category of loans. The methodology to collectively evaluate the acquired loans outside the scope of ASC 310-30 includes the application of a number of environmental factors that reflect management’s best estimate of the level of incremental credit losses that might be recognized given current conditions. This is reviewed as part of the allowance for loan loss adequacy analysis. As the loan portfolio matures and environmental factors change, the loan portfolio will be reassessed each quarter to determine an appropriate reserve allowance. Additionally, the Company considers the need for an additional reserve for acquired loans accounted for outside of the scope of ASC 310-30 under ASC 310-20. At acquisition date, the Bank determined a fair value mark with credit and interest rate components. Under the Company’s model, the impairment evaluation process involves comparing the carrying value of acquired loans, including the unamortized premium or discount, to the calculated reserve allowance. If necessary, the Company books an additional reserve to account for shortfalls identified through this calculation. A decrease in the expected cash flows in subsequent periods requires the establishment of an allowance for loan losses at that time for ASC 310-30 loans.
Bank-Owned Life Insurance	Bank-Owned Life Insurance Bank-owned life insurance policies are reflected on the consolidated balance sheets at cash surrender value. Changes in the net cash surrender value of the policies, as well as insurance proceeds received, are reflected in non-interest income on the consolidated statements of operations and are not subject to income taxes.
Foreclosed and Repossessed Assets	Foreclosed and Repossessed Assets Other real estate owned is comprised of real estate acquired through foreclosure proceedings or acceptance of a deed in lieu of foreclosure. Repossessed collateral is primarily comprised of aircraft, motor vehicles, and taxi medallions. Both other real estate owned and repossessed collateral are held for sale and are initially recorded at the fair value less estimated costs to sell at the date of foreclosure or repossession, establishing a new cost basis. The shortfall, if any, of the loan balance over the fair value of the property or collateral, less cost to sell, at the time of transfer from loans to other real estate owned or repossessed collateral is charged to the allowance for loan losses. Subsequent to transfer, the asset is carried at lower of cost or fair value less cost to sell and periodically evaluated for impairment. Subsequent impairments in the fair value of other real estate owned and repossessed collateral are charged to expense in the period incurred. Net operating income or expense related to other real estate owned and repossessed collateral is included in operating expenses in the accompanying consolidated statements of income. Because of changing market conditions, there are inherent uncertainties in the assumptions with respect to the estimated fair value of other real estate owned and repossessed collateral. Because of these inherent uncertainties, the amount ultimately realized on other real estate owned and repossessed collateral may differ from the amounts reflected in the consolidated financial statements.
Capitalized Servicing Rights	Capitalized Servicing Rights Capitalized servicing rights are included in “other assets” in the consolidated balance sheet. Servicing assets are initially recognized as separate assets at fair value when rights are acquired through purchase or through sale of financial assets with servicing retained. The Company's servicing rights accounted for under the fair value method are carried on the consolidated balance sheet at fair value with changes in fair value recorded in income in the period in which the change occurs. Changes in the fair value of servicing rights are primarily due to changes in valuation inputs, assumptions, and the collection and realization of expected cash flows. The Company’s servicing rights accounted for under the amortization method are initially recorded at fair value. Under that method, capitalized servicing rights are charged to expense in proportion to and over the period of estimated net servicing income. Fair value of the servicing rights is based on a valuation model that calculates the present value of estimated future net servicing income. The valuation model incorporates assumptions that market participants would use in estimating future net servicing income, such as the cost to service, the discount rate, prepayment speeds and default rates and losses. Impairment is recognized through a valuation allowance for an individual tranche, to the extent that fair value is less than the capitalized amount for the tranches. If the Company later determines that all or a portion of the impairment no longer exists for a particular tranche, a reduction of the allowance may be recorded as an increase to income.
Premises and Equipment	Premises and Equipment Land is carried at cost. Buildings, improvements, and equipment are carried at cost less accumulated depreciation and amortization computed on the straight-line method over the estimated useful lives of the assets. Leasehold improvements are amortized on the straight-line method over the shorter of the lease term, plus optional terms if certain conditions are met, or the estimated useful life of the asset.
Goodwill	Goodwill Goodwill represents the excess of the purchase price over the fair value of the net assets acquired in a business combination. Goodwill is assessed annually for impairment, and more frequently if events or changes in circumstances indicate that there may be an impairment. Adverse changes in the economic environment, declining operations, unanticipated competition, loss of key personnel, or other factors could result in a decline in the implied fair value of goodwill. If the implied fair value of goodwill is less than the carrying amount, a loss would be recognized in other non-interest expense to reduce the carrying amount to the implied fair value of goodwill. The Company performs an annual qualitative assessment of whether it is more likely than not that the reporting unit's fair value is less than its carrying amount. If the results of the qualitative assessment suggest goodwill impairment, the Company would perform a two-step impairment test through the application of various quantitative valuation methodologies. Step 1, used to identify instances of potential impairment, compares the fair value of the reporting unit with its carrying amount, including goodwill. If the carrying amount, including goodwill, exceeds its fair value, the second step of the goodwill impairment analysis is performed to measure the amount of impairment loss, if any. Step 2 of the goodwill impairment analysis compares the implied fair value of reporting unit goodwill with the carrying amount of that goodwill. If the carrying amount of goodwill for the reporting unit exceeds the implied fair value of the reporting unit’s goodwill, an impairment loss is recognized in an amount equal to that excess. Subsequent reversals of goodwill impairment are prohibited. The Company may elect to bypass the qualitative assessment and begin with Step 1.
Other Intangibles	Other Intangibles Intangible assets are acquired assets that lack physical substance but can be distinguished from goodwill because of contractual or other legal rights or the asset is capable of being sold or exchanged either on its own or in combination with a related contract, asset or liability. The fair values of these assets are generally determined based on appraisals and are subsequently amortized on a straight-line basis or an accelerated basis over their estimated lives. Management assesses the recoverability of these intangible assets whenever events or changes in circumstances indicate that their carrying value may not be recoverable. If the carrying amount exceeds fair value, an impairment charge is recorded to income.
Transfers of Financial Assets	Transfers of Financial Assets Transfers of an entire financial asset, group of entire financial assets, or a participating interest in an entire financial asset are accounted for as sales when control over the assets has been surrendered. Control over transferred assets is deemed to be surrendered when (1) the assets have been isolated from the Company, (2) the transferee obtains the right to pledge or exchange the transferred assets, and (3) the Company does not maintain effective control over the transferred assets.
Income Taxes	Income Taxes Deferred income taxes are recognized for the tax consequences of temporary differences by applying enacted statutory tax rates applicable for future years to differences between financial statement and tax bases of existing assets and liabilities. The effect of tax rate changes on deferred taxes is recognized in the income tax provision in the period that includes the enactment date. A tax valuation allowance is established, as needed, to reduce net deferred tax assets to the amount expected to be realized. In the event it becomes more likely than not that some or all of the deferred tax asset allowances will not be needed, the valuation allowance will be adjusted. In the ordinary course of business there is inherent uncertainty in quantifying the Company’s income tax positions. Income tax positions and recorded tax benefits are based upon management’s evaluation of the facts, circumstances, and information available at the reporting date. For those tax positions where it is more likely than not that a tax benefit will be sustained, we have determined the amount of the tax benefit to be recognized by estimating the largest amount of tax benefit that has a greater than 50% likelihood of being realized upon ultimate settlement with a taxing authority that has full knowledge of all relevant information. For those income tax positions where it is more-likely-than-not that a tax benefit will not be sustained, no tax benefit has been recognized in the financial statements. Where applicable, associated interest and penalties have also been recognized. We recognize accrued interest and penalties related to unrecognized tax benefits as a component of income tax expense.
Insurance Commissions	Insurance Commissions Commission revenue is recognized as of the effective date of the insurance policy or the date the customer is billed, whichever is later, net of return commissions related to policy cancellations. In addition, the Company may receive additional performance commissions based on achieving certain sales and loss experience measures. Such commissions are recognized when determinable, which is generally when such commissions are received or when the Company receives data from the insurance companies that allows the reasonable estimation of these amounts.
Advertising Costs	Advertising Costs Advertising costs are expensed as incurred.
Stock-Based Compensation	Stock-Based Compensation The Company measures and recognizes compensation cost relating to share-based payment transactions based on the grant-date fair value of the equity instruments issued. The fair value of restricted stock is recorded as unearned compensation. The deferred expense is amortized to compensation expense based on one of several permitted attribution methods over the longer of the required service period or performance period. For performance-based restricted stock 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. Income tax benefits and/or tax deficiencies related to stock compensation determined as the difference between compensation cost recognized for financial reporting purposes and the deduction for tax, are recognized in the income statement as income tax expense or benefit in the period in which they occur.
Wealth Management	Wealth Management Wealth management assets held in a fiduciary or agent capacity are not included in the accompanying consolidated balance sheets because they are not assets of the Company. Fees earned from wealth management activities are amortized over the period of the service performed.
Derivative Instruments and Hedging Activities	Derivative Instruments and Hedging Activities The Company enters into interest rate swap agreements as part of the Company’s interest rate risk management strategy for certain assets and liabilities and not for speculative purposes. Based on the Company’s intended use for the interest rate swap at inception, the Company designates the derivative as either an economic hedge of an asset or liability or a hedging instrument subject to the hedge accounting provisions of ASC 815, “Derivatives and Hedging.” Interest rate swaps designated as economic hedges are recorded at fair value within other assets or liabilities. Changes in the fair value of these derivatives are recorded directly through earnings. For interest rate swaps that management intends to apply the hedge accounting provisions of ASC 815, the Company formally documents at inception all relationships between hedging instruments and hedged items, as well as its risk management objectives and strategies for undertaking the various hedges. Additionally, the Company uses dollar offset or regression analysis at the hedge’s inception and for each reporting period thereafter, to assess whether the derivative used in its hedging transaction is expected to be and has been highly effective in offsetting changes in the fair value or cash flows of the hedged item. The Company discontinues hedge accounting when it is determined that a derivative is not expected to be or has ceased to be highly effective as a hedge, and then reflects changes in fair value of the derivative in earnings after termination of the hedge relationship. The Company has characterized its interest rate swaps that qualify under ASC 815 hedge accounting as cash flow hedges. Cash flow hedges are used to minimize the variability in cash flows of assets or liabilities, or forecasted transactions caused by interest rate fluctuations, and are recorded at fair value in other assets or liabilities within the Company’s balance sheets. Changes in the fair value of these cash flow hedges are initially recorded in accumulated other comprehensive income and subsequently reclassified into earnings when the forecasted transaction affects earnings. Any hedge ineffectiveness assessed as part of the Company’s quarterly analysis is recorded directly to earnings. The Company enters into commitments to lend with borrowers, and forward commitments to sell loans or to-be-announced mortgage-backed bonds to investors to hedge against the inherent interest rate and pricing risk associated with selling loans. The commitments to lend generally terminate once the loan is funded, the lock period expires or the borrower decides not to contract for the loan. The forward commitments generally terminate once the loan is sold, the commitment period expires or the borrower decides not to contract for the loan. These commitments are considered derivatives which are accounted for by recognizing their estimated fair value on the Consolidated Balance Sheets as either a freestanding asset or liability. See Note 16 to the Consolidated Financial Statements for more information on commitments to lend and forward commitments.
Off-Balance Sheet Financial Instruments	Off-Balance Sheet Financial Instruments In the ordinary course of business, the Company enters into off-balance sheet financial instruments, consisting primarily of credit related financial instruments. These financial instruments are recorded in the financial statements when they are funded or related fees are incurred or received.
Fair Value Hierarchy	Fair Value Hierarchy The Company groups assets and liabilities that are measured at fair value in three levels, based on the markets in which the assets and liabilities are traded and the reliability of the assumptions used to determine fair value. Level 1 - Valuation is based on quoted prices in active markets for identical assets or liabilities. Valuations are obtained from readily available pricing sources for market transactions involving identical assets or liabilities. Level 2 - Valuation is based on observable inputs other than Level 1 prices, such as quoted prices for similar assets or liabilities; quoted prices in markets that are not active; or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities. Level 3 - Valuation is based on unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities. Level 3 assets and liabilities include financial instruments whose value is determined using unobservable techniques, as well as instruments for which the determination of fair value requires significant management judgment or estimation.
Employee Benefits	Employee Benefits The Company maintains an employer sponsored 401(k) plan to which participants may make contributions in the form of salary deferrals and the Company provides matching contributions in accordance with the terms of the plan. Contributions due under the terms of the defined contribution plans are accrued as earned by employees. Due to the Rome Bancorp acquisition in 2011, the Company inherited a noncontributory, qualified, defined benefit pension plan for certain employees who met age and service requirements; as well as other post-retirement benefits, principally health care and group life insurance. The Rome pension plan and postretirement benefits that were acquired in connection with the whole-bank acquisition in the second quarter of 2011 were frozen prior to the close of the transaction. The pension benefit in the form of a life annuity is based on the employee’s combined years of service, age, and compensation. The Company also has a long-term care post-retirement benefit plan for certain executives where upon disability, associated benefits are funded by insurance policies or paid directly by the Company. In order to measure the expense associated with the Plans, various assumptions are made including the discount rate, expected return on plan assets, anticipated mortality rates, and expected future healthcare costs. The assumptions are based on historical experience as well as current facts and circumstances. The Company uses a December 31 measurement date for its Plans. As of the measurement date, plan assets are determined based on fair value, generally representing observable market prices. The projected benefit obligation is primarily determined based on the present value of projected benefit distributions at an assumed discount rate. Net periodic pension benefit costs include interest costs based on an assumed discount rate, the expected return on plan assets based on actuarially derived market-related values, and the amortization of net actuarial losses. Net periodic postretirement benefit costs include service costs, interest costs based on an assumed discount rate, and the amortization of prior service credits and net actuarial gains. Differences between expected and actual results in each year are included in the net actuarial gain or loss amount, which is recognized in other comprehensive income. The net actuarial gain or loss in excess of a 10% corridor is amortized in net periodic benefit cost over the average remaining service period of active participants in the Plans. The prior service credit is amortized over the average remaining service period to full eligibility for participating employees expected to receive benefits. The Company recognizes in its statement of condition an asset for a plan’s overfunded status or a liability for a plan’s underfunded status. The Company also measures the Plans’ assets and obligations that determine its funded status as of the end of the fiscal year and recognizes those changes in other comprehensive income, net of tax.
Operating Segments	Operating Segments The Company operates as one consolidated reportable segment. The chief operating decision-maker evaluates consolidated results and makes decisions for resource allocation on this same data. Management periodically reviews and redefines its segment reporting as internal reporting practices evolve and components of the business change. The consolidated financial statements reflect the financial results of the Company's one reportable operating segment.
Recent Accounting Pronouncements and Future Application of Accounting Pronouncements	Recently Adopted Accounting Principles Effective January 1, 2017, the following new accounting guidance was adopted by the Company: • ASU No. 2016-05, Effect of Derivative Contract Novations on Existing Hedge Accounting Relationships; • ASU No. 2016-06, Contingent Put and Call Options in Debt Instruments; • ASU No. 2016-07, Simplifying the Transition to the Equity Method of Accounting • ASU No. 2016-15, Classification of Certain Cash Receipts and Cash Payments; and • ASU No. 2017-08, Premium Amortization on Purchased Callable Debt Securities The adoption of these accounting standards did not have a material impact on the Company's financial statements. Future Application of Accounting Pronouncements In May 2014, the FASB issued ASU No. 2014-09, “Revenue from Contracts with Customers.” This ASU provides a revenue recognition framework for any entity that either enters into contracts with customers to transfer goods or services or enters into contracts for the transfer of non-financial assets unless those contracts are within the scope of other accounting standards. The standard permits the use of either the retrospective or cumulative effect transition method. This ASU is effective for annual and interim periods in fiscal years beginning after December 15, 2017. This ASU impacts the Company’s wealth management fees, insurance commissions and fees, administrative services for customer deposit accounts, interchange fees, and sale of owned real estate properties. ASU 2014-09, as amended, became effective for the Company on January 1, 2018. The adoption of ASU 2014-09 on January 1, 2018 was not material to our consolidated financial statements. In January 2016, the FASB issued ASU No. 2016-01, “Recognition and Measurement of Financial Assets and Financial Liabilities.” This ASU requires an entity to: i) measure equity investments at fair value through net income, with certain exceptions; (ii) present in other comprehensive income the changes in instrument-specific credit risk for financial liabilities measured using the fair value option; (iii) present financial assets and financial liabilities by measurement category and form of financial asset; (iv) calculate the fair value of financial instruments for disclosure purposes based on an exit price and; (v) assess a valuation allowance on deferred tax assets related to unrealized losses of available-for-sale debt securities in combination with other deferred tax assets. The guidance provides an election to subsequently measure certain non-marketable equity investments at cost less any impairment and adjusted for certain observable price changes. The guidance also requires a qualitative impairment assessment of such equity investments and amends certain fair value disclosure requirements. The guidance is effective for annual periods beginning after December 15, 2017. ASU 2016-01 became effective for the Company on January 1, 2018. The adoption will increase the volatility of other income (expense), net, as a result of the re-measurement of our equity and cost method investments. The adoption of ASU 2016-01 on January 1, 2018 was not material to our consolidated financial statements. In February 2016, the FASB issued ASU No. 2016-02, “Leases”. The new pronouncement improves the transparency and comparability of financial reporting around leasing transactions and more closely aligns accounting for leases with the recently issued International Financial Reporting Standard. The pronouncement affects all entities that are participants to leasing agreements. From a lessee accounting perspective, the ASU requires a lessee to recognize assets and liabilities on the balance sheet for operating leases and changes many key definitions, including the definition of a lease. The ASU includes a short-term lease exception for leases with a term of twelve months or less, in which a lessee can make an accounting policy election not to recognize lease assets and lease liabilities. Lessees will continue to differentiate between finance leases (previously referred to as capital leases) and operating leases, using classification criteria that are substantially similar to the previous guidance. For lessees, the recognition, measurement, and presentation of expenses and cash flows arising from a lease have not significantly changed from previous GAAP. From a lessor accounting perspective, the guidance is largely unchanged, except for targeted improvements to align with new terminology under lessee accounting and with the updated revenue recognition guidance in Topic 606. For sale-leaseback transactions, for a sale to occur the transfer must meet the sale criteria under the new revenue standard, ASC 606. Entities will not be required to reassess transactions previously accounted under then existing guidance. Additionally, the ASU includes additional quantitative and qualitative disclosures required by lessees and lessors to help users better understand the amount, timing, and uncertainty of cash flows arising from leases. ASU No. 2016-02 is effective for fiscal years beginning after December 31, 2018, and interim periods within those fiscal years. Lessees and lessors are required to recognize and measure leases at the beginning of the earliest period presented using a modified retrospective approach. The modified retrospective approach includes a number of optional practical expedients that entities may elect to apply as well as transition guidance specific to nonstandard leasing transactions. The Company is currently evaluating the provisions of ASU No. 2016-02 to determine the potential impact the new standard will have on the Company's consolidated financial statements. It is expected that assets and liabilities will increase based on the present value of remaining lease payments for leases in place at the adoption date; however, this is not expected to be material to the Company's results of operations or financial position. The Company continues to evaluate the extent of potential impact the new guidance will have on the Company’s consolidated financial statements. In June 2016, the FASB issued ASU No. 2016-13, “Measurement of Credit Losses on Financial Instruments.” This ASU improves financial reporting by requiring timelier recording of credit losses on loans and other financial instruments. The ASU requires companies to measure all expected credit losses for financial assets held at the reporting date based on historical experience, current conditions, and reasonable and supportable forecasts. Forward-looking information will now be used in credit loss estimates. The ASU requires enhanced disclosures to provide better understanding surrounding significant estimates and judgments used in estimating credit losses, as well as the credit quality and underwriting standards of a company’s portfolio. These disclosures include qualitative and quantitative requirements that provide additional information about the amounts recorded in the financial statements. Additionally, the ASU amends the accounting for credit losses on available-for-sale debt securities and purchased financial assets with credit deterioration. Most debt instruments will require a cumulative-effect adjustment to retained earnings on the statement of financial position as of the beginning of the first reporting period in which the guidance is adopted (modified retrospective approach). However, there is instrument-specific transition guidance. ASU No. 2016-13 is effective for interim and annual periods beginning after December 15, 2019. Early application will be permitted for interim and annual periods beginning after December 15, 2018. The Company is evaluating the provisions of ASU No. 2016-13, and will closely monitor developments and additional guidance to determine the potential impact on the Company's consolidated financial statements. The Company expects the primary changes to be the application of the expected credit loss model to the financial statements. In addition, the Company expects the guidance to change the presentation of credit losses within the available-for-sale fixed maturities portfolio through an allowance method rather than as a direct write-down. The expected credit loss model will require a financial asset to be presented at the net amount expected to be collected. The allowance method for available-for-sale debt securities will allow the Company to record reversals of credit losses if the estimate of credit losses declines. The Company is in the process of identifying and implementing required changes to loan loss estimation models and processes and evaluating the impact of this new accounting guidance, which at the date of adoption is expected to increase the allowance for credit losses with a resulting negative adjustment to retained earnings. In January 2017, the FASB issued ASU No. 2017-04, “Intangibles: Goodwill and Other: Simplifying the Test for Goodwill Impairment.” The ASU simplifies the test for goodwill impairment by eliminating the second step of the current two-step method. Under the new accounting guidance, entities will compare the fair value of a reporting unit with its carrying amount. If the carrying amount exceeds the reporting unit’s fair value, the entity is required to recognize an impairment charge for this amount. Current guidance requires an entity to proceed to a second step, whereby the entity would determine the fair value of its assets and liabilities. The new method applies to all reporting units. The performance of a qualitative assessment is still allowable. This accounting guidance is effective prospectively for interim and annual reporting periods beginning after December 15, 2019. Early adoption is permitted. The Company is in the process of evaluating the impact of adopting the new accounting guidance, but it is not expected to have a material impact. In August 2017, the FASB issued ASU No. 2017-12, “Derivatives and Hedging: Targeted Improvements to Accounting for Hedging Activities.” The purpose of this updated guidance is to better align a company’s financial reporting for hedging activities with the economic objectives of those activities. ASU No. 2017-12 is effective for public business entities for fiscal years beginning after December 15, 2018, with early adoption, including adoption in an interim period, permitted. ASU 2017-12 requires a modified retrospective transition method in which the Company will recognize the cumulative effect of the change on the opening balance of each affected component of equity in the consolidated balance sheet as of the date of adoption. While the Company continues to assess all potential impacts of the standard, we currently expect adoption to have an immaterial impact on our consolidated financial statements. In February 2018, the FASB issued ASU No. 2018-02, “Income statement - Reporting Comprehensive Income (Topic 220) Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income” which will allow a reclassification from accumulated other comprehensive income to retained earnings for stranded tax effects resulting from the Tax Cuts and Jobs Act of 2017. These amendments are effective for all entities for fiscal years beginning after December 15, 2018. For interim periods within those fiscal years, early adoption of the amendment is permitted including public business entities for reporting periods for which financial statements have not yet been issued. The Company will reclassify the stranded tax effect in accumulated other comprehensive income to retained earnings as required under the new accounting guidance beginning March 31, 2018.

ACQUISITIONS (Tables)

ACQUISITIONS (Tables)	12 Months Ended
	Dec. 31, 2017
Business Combinations [Abstract]
Summary of Consideration Assets Acquired and Liabilities Assumed	The following table provides a summary of the assets acquired and liabilities assumed and the associated fair value adjustments as recorded by the Company at acquisition: Fair Value As Recorded by (in thousands) As Acquired Adjustments the Company Consideration Paid: Company common stock issued to Commerce common shareholders $ 188,599 Company preferred stock issued to certain Commerce shareholders 40,633 Cash in lieu paid to Commerce shareholders 1 Total consideration paid $ 229,233 Recognized amounts of identifiable assets acquired and (liabilities) assumed, at fair value: Cash and short-term investments $ 374,611 $ — $ 374,611 Investment securities 115,274 (1,427 ) (a) 113,847 Loans, net 1,327,256 (86,505 ) (b) 1,240,751 Premises and equipment 8,931 5,346 (c) 14,277 Core deposit intangibles — 22,400 (d) 22,400 Deferred tax assets, net 7,956 26,580 (e) 34,536 Goodwill and other intangibles 11,233 (11,233 ) (f) — Other assets 52,709 (3,664 ) (g) 49,045 Deposits (1,710,872 ) (1,180 ) (h) (1,712,052 ) Borrowings (19,542 ) — (19,542 ) Other liabilities (5,086 ) 265 (4,821 ) Total identifiable net assets $ 162,470 $ (49,418 ) $ 113,052 Goodwill $ 116,181 ________________________________ Explanation of Certain Fair Value Adjustments (a) The adjustment represents the write down of the book value of securities to their estimated fair value at the date of acquisition. (b) The adjustment represents the write-off of $15.0 million in allowance for loan and lease losses and the write down of the book value of loans to their estimated fair value based on interest rates and expected cash flows as of the acquisition date, which includes an estimate of expected loan loss inherent in the portfolio. The valuation of the loans is provisional. Loans with evidence of credit deterioration at acquisition are accounted for under ASC 310-30 and had a book value of $163.1 million and had a fair value of $71.1 million . Non-impaired loans accounted for under ASC 310-20 had a book value of $1.18 billion and have a fair value of $1.17 billion . ASC 310-30 loans have a $10.8 million fair value adjustment that is accretable in earnings. ASC 310-20 loans have a $4.0 million fair value adjustment premium that is amortized over the remaining term of the loans using the effective interest method, or a straight-line method if the loan is a revolving credit facility. (c) The adjustment represents an increased fair value based on the appraised value of Commerce’s owned branches and headquarters comprised of $5.7 million for buildings and $0.7 million for land. This was offset by a $1.0 million reduction of the book value of furniture, fixtures, and equipment, to their estimated fair value and the immediate expensing of equipment not meeting the thresholds for capitalization in accordance with Company policy. The adjustments will be depreciated over the remaining estimated economic lives of the assets. (d) The adjustment represents the value of the core deposit base assumed in the acquisition. The core deposit asset was recorded as an identifiable intangible asset and will be amortized over the estimated useful life of the deposit base ( 10 years ). (e) Represents net deferred tax assets resulting from the fair value adjustments related to the acquired assets and liabilities, identifiable intangibles, and other purchase accounting adjustments. (f) Represents the write-off of goodwill and intangible assets from a prior Commerce acquisition. (g) The adjustment includes a $3.5 million write-down of repossessed assets based on market report data. (h) The adjustment is necessary because the weighted average interest rate of time deposits exceeded the cost of similar funding at the time of acquisition. The amount will be amortized over the estimated useful life of nine months.
Schedule of Acquired Loan Portfolio	nformation about the Commerce Bank acquired loan portfolio subject to ASC 310-30 as of October 13, 2017 is as follows (in thousands): ASC 310-30 Loans Gross contractual receivable amounts at acquisition $ 163,125 Contractual cash flows not expected to be collected (nonaccretable discount) (81,205 ) Expected cash flows at acquisition 81,920 Interest component of expected cash flows (accretable discount) (10,815 ) Fair value of acquired loans $ 71,105
Pro Forma Financial Information	Information in the following table is shown in thousands, except earnings per share: Pro Forma (unaudited) 2017 2016 Net interest income $ 344,797 $ 302,012 Non-interest income 134,818 77,192 Income available to common shareholders 77,340 78,859

SECURITIES (Tables)

SECURITIES (Tables)	12 Months Ended
	Dec. 31, 2017
Investments, Debt and Equity Securities [Abstract]
Summary of securities available for sale ("AFS") and securities	The following is a summary of securities available for sale (“AFS”) and securities held to maturity (“HTM”): (In thousands) Amortized Gross Gross Fair Value December 31, 2017 Securities available for sale Debt securities: Municipal bonds and obligations $ 113,427 $ 5,012 $ (206 ) $ 118,233 Agency collateralized mortgage obligations 859,705 397 (8,944 ) 851,158 Agency mortgage-backed securities 218,926 279 (2,265 ) 216,940 Agency commercial mortgage-backed securities 64,025 41 (1,761 ) 62,305 Corporate bonds 110,076 882 (237 ) 110,721 Trust preferred securities 11,334 343 — 11,677 Other bonds and obligations 9,757 154 (31 ) 9,880 Total debt securities 1,387,250 7,108 (13,444 ) 1,380,914 Marketable equity securities 36,483 9,211 (509 ) 45,185 Total securities available for sale 1,423,733 16,319 (13,953 ) 1,426,099 Securities held to maturity Municipal bonds and obligations 270,310 8,675 (90 ) 278,895 Agency collateralized mortgage obligations 73,742 1,045 (486 ) 74,301 Agency mortgage-backed securities 7,892 — (164 ) 7,728 Agency commercial mortgage-backed securities 10,481 — (268 ) 10,213 Tax advantaged economic development bonds 34,357 596 (1,135 ) 33,818 Other bonds and obligations 321 — — 321 Total securities held to maturity 397,103 10,316 (2,143 ) 405,276 Total $ 1,820,836 $ 26,635 $ (16,096 ) $ 1,831,375 December 31, 2016 Securities available for sale Debt securities: Municipal bonds and obligations $ 117,910 $ 2,955 $ (1,049 ) $ 119,816 Agency collateralized mortgage obligations 652,680 2,522 (3,291 ) 651,911 Agency mortgage-backed securities 230,308 557 (2,181 ) 228,684 Agency commercial mortgage-backed securities 65,673 229 (1,368 ) 64,534 Corporate bonds 56,320 408 (722 ) 56,006 Trust preferred securities 11,578 368 (59 ) 11,887 Other bonds and obligations 10,979 195 (16 ) 11,158 Total debt securities 1,145,448 7,234 (8,686 ) 1,143,996 Marketable equity securities 47,858 19,296 (1,613 ) 65,541 Total securities available for sale 1,193,306 26,530 (10,299 ) 1,209,537 Securities held to maturity Municipal bonds and obligations 203,463 3,939 (2,416 ) 204,986 Agency collateralized mortgage-backed securities 75,655 1,281 (411 ) 76,525 Agency mortgage-backed securities 9,102 — (243 ) 8,859 Agency commercial mortgage-backed securities 10,545 — (434 ) 10,111 Tax advantaged economic development bonds 35,278 1,596 — 36,874 Other bonds and obligations 325 — — 325 Total securities held to maturity 334,368 6,816 (3,504 ) 337,680 Total $ 1,527,674 $ 33,346 $ (13,803 ) $ 1,547,217
Schedule of amortized cost and estimated fair value of available for sale (AFS) and held to maturity (HTM) securities, segregated by contractual maturity	The amortized cost and estimated fair value of available for sale (AFS) and held to maturity (HTM) securities, segregated by contractual maturity at year-end 2017 are presented below. Expected maturities may differ from contractual maturities because issuers may have the right to call or prepay obligations. Mortgage-backed securities and collateralized mortgage obligations are shown in total, as their maturities are highly variable. Equity securities have no maturity and are also shown in total. Available for sale Held to maturity (In thousands) Amortized Fair Amortized Fair Within 1 year $ 622 $ 623 $ 1,261 $ 1,261 Over 1 year to 5 years 32,659 32,972 25,892 26,422 Over 5 years to 10 years 75,261 76,745 8,752 8,917 Over 10 years 136,052 140,171 269,083 276,434 Total bonds and obligations 244,594 250,511 304,988 313,034 Marketable equity securities 36,483 45,185 — — Mortgage-backed securities 1,142,656 1,130,403 92,115 92,242 Total $ 1,423,733 $ 1,426,099 $ 397,103 $ 405,276
Schedule of amortized cost and fair values of pledged securities	The total amortized cost and fair values of these pledged securities follows. Additionally, there is a blanket lien on certain securities to collateralize borrowings from the FHLBB, as discussed further in Note 12 - Borrowed Funds. 2017 2016 (In thousands) Amortized Fair Amortized Fair Securities pledged to swap counterparties $ 24,410 $ 24,240 $ 51,292 $ 51,290 Securities pledged for municipal deposits 210,382 214,513 147,950 148,435 Total $ 234,792 $ 238,753 $ 199,242 $ 199,725
Schedule of components of net realized gains and losses on the sale of AFS securities	The components of net realized gains and losses on the sale of AFS securities are as follows. These amounts were reclassified out of accumulated other comprehensive income and into earnings: (In thousands) 2017 2016 2015 Gross realized gains $ 13,877 $ 2,762 $ 4,567 Gross realized losses (1,279 ) (3,313 ) (2,457 ) Net realized gains/(losses) $ 12,598 $ (551 ) $ 2,110
Schedule of securities with unrealized losses, segregated by the duration of their continuous unrealized loss positions	Securities with unrealized losses, segregated by the duration of their continuous unrealized loss positions, are summarized as follows: Less Than Twelve Months Over Twelve Months Total (In thousands) Gross Fair Gross Fair Gross Fair December 31, 2017 Securities available for sale Debt securities: Municipal bonds and obligations $ — $ — $ 206 $ 8,985 $ 206 $ 8,985 Agency collateralized mortgage obligations 6,849 655,479 2,095 80,401 8,944 735,880 Agency mortgage-backed securities 765 95,800 1,500 65,323 2,265 161,123 Agency commercial mortgage-back securities 334 17,379 1,427 39,268 1,761 56,647 Corporate bonds 1 328 236 15,769 237 16,097 Trust preferred securities — — — — — — Other bonds and obligations 11 1,096 20 2,004 31 3,100 Total debt securities 7,960 770,082 5,484 211,750 13,444 981,832 Marketable equity securities 509 3,731 — — 509 3,731 Total securities available for sale $ 8,469 $ 773,813 $ 5,484 $ 211,750 $ 13,953 $ 985,563 Securities held to maturity Municipal bonds and obligations 35 10,213 55 2,059 90 12,272 Agency collateralized mortgage obligations — — 486 12,946 486 12,946 Agency mortgage-backed securities — — 164 7,728 164 7,728 Agency commercial mortgage-back securities — — 268 10,213 268 10,213 Tax advantaged economic development bonds 1,135 7,305 — — 1,135 7,305 Total securities held to maturity 1,170 17,518 973 32,946 2,143 50,464 Total $ 9,639 $ 791,331 $ 6,457 $ 244,696 $ 16,096 $ 1,036,027 December 31, 2016 Securities available for sale Debt securities: Municipal bonds and obligations $ 1,049 $ 13,839 $ — $ — $ 1,049 $ 13,839 Agency collateralized mortgage obligations 3,291 319,448 — — 3,291 319,448 Agency mortgage-backed securities 2,153 130,766 28 2,061 2,181 132,827 Agency commercial mortgage-backed securities 1,368 44,860 — — 1,368 44,860 Corporate bonds 11 4,780 711 19,655 722 24,435 Trust preferred securities — — 59 1,204 59 1,204 Other bonds and obligations 15 3,014 1 27 16 3,041 Total debt securities 7,887 516,707 799 22,947 8,686 539,654 Marketable equity securities 157 6,600 1,456 5,927 1,613 12,527 Total securities available for sale $ 8,044 $ 523,307 $ 2,255 $ 28,874 $ 10,299 $ 552,181 Securities held to maturity Municipal bonds and obligations 2,416 69,308 — — 2,416 69,308 Agency collateralized mortgage obligations 411 14,724 — — 411 14,724 Agency mortgage-backed securities 243 8,859 — — 243 8,859 Agency commercial mortgage-back securities 434 10,111 — — 434 10,111 Total securities held to maturity 3,504 103,002 — — 3,504 103,002 Total $ 11,548 $ 626,309 $ 2,255 $ 28,874 $ 13,803 $ 655,183

LOANS (Tables)

LOANS (Tables)	12 Months Ended
	Dec. 31, 2017
Receivables [Abstract]
Schedule of Loans	The following is a summary of total loans: December 31, 2017 December 31, 2016 (In thousands) Business Activities Loans Acquired Loans Total Business Activities Loans Acquired Loans Total Commercial real estate: Construction $ 181,371 $ 84,965 $ 266,336 $ 253,302 $ 34,207 $ 287,509 Single and multi-family 217,083 206,082 423,165 191,819 125,672 317,491 Other commercial real estate 1,819,253 755,988 2,575,241 1,481,223 530,215 2,011,438 Total commercial real estate 2,217,707 1,047,035 3,264,742 1,926,344 690,094 2,616,438 Commercial and industrial loans 1,182,569 621,370 1,803,939 908,102 153,936 1,062,038 Total commercial loans 3,400,276 1,668,405 5,068,681 2,834,446 844,030 3,678,476 Residential mortgages: 1-4 family 1,808,024 289,373 2,097,397 1,583,794 297,355 1,881,149 Construction 5,177 233 5,410 11,178 804 11,982 Total residential mortgages 1,813,201 289,606 2,102,807 1,594,972 298,159 1,893,131 Consumer loans: Home equity 294,954 115,227 410,181 313,521 80,279 393,800 Auto and other 603,767 113,902 717,669 478,368 106,012 584,380 Total consumer loans 898,721 229,129 1,127,850 791,889 186,291 978,180 Total loans $ 6,112,198 $ 2,187,140 $ 8,299,338 $ 5,221,307 $ 1,328,480 $ 6,549,787
Schedule of Total Unamortized Net Costs and Premiums Included in the Total Loans for Historical Loans	Total unamortized net costs and premiums included in the year-end total loans for business activity loans were the following: (In thousands) December 31, 2017 December 31, 2016 Unamortized net loan origination costs $ 24,669 $ 21,972 Unamortized net premium on purchased loans 4,311 4,849 Total unamortized net costs and premiums $ 28,980 $ 26,821
Schedule of Activity in the Accretable Yield for the Acquired Loan Portfolio that Falls Under the Purview of ASC 310-30, Accounting for Certain Loans or Debt Securities Acquired in a Transfer	The following table summarizes activity in the accretable yield for the acquired loan portfolio that falls under the purview of ASC 310-30, Loans and Debt Securities Acquired with Deteriorated Credit Quality : (In thousands) 2017 2016 2015 Balance at beginning of period $ 8,738 $ 6,925 $ 2,541 Acquisitions 10,815 6,125 4,777 Reclassification from nonaccretable difference for loans with improved cash flows (23 ) 2,488 3,640 Changes in expected cash flows that do not affect nonaccretable difference (2,380 ) (3,018 ) — Reclassification to TDR — (185 ) — Accretion (5,589 ) (3,597 ) (4,033 ) Balance at end of period $ 11,561 $ 8,738 $ 6,925
Summary of Past Due Loans	The following is a summary of past due loans at December 31, 2017 and 2016: Business Activities Loans (in thousands) 30-59 Days 60-89 Days >90 Days Past Due Total Past Current Total Loans Past Due > December 31, 2017 Commercial real estate: Construction $ — $ — $ — $ — $ 181,371 $ 181,371 $ — Single and multi-family — — 451 451 216,632 217,083 — Commercial real estate 1,925 48 5,023 6,996 1,812,257 1,819,253 457 Total 1,925 48 5,474 7,447 2,210,260 2,217,707 457 Commercial and industrial loans Total 4,031 1,912 6,023 11,966 1,170,603 1,182,569 128 Residential mortgages: 1-4 family 2,412 242 2,186 4,840 1,803,184 1,808,024 520 Construction — — — — 5,177 5,177 — Total 2,412 242 2,186 4,840 1,808,361 1,813,201 520 Consumer loans: Home equity 444 1,235 1,747 3,426 291,528 294,954 120 Auto and other 3,389 599 1,597 5,585 598,182 603,767 143 Total 3,833 1,834 3,344 9,011 889,710 898,721 263 Total $ 12,201 $ 4,036 $ 17,027 $ 33,264 $ 6,078,934 $ 6,112,198 $ 1,368 Business Activities Loans (in thousands) 30-59 Days 60-89 Days >90 Days Past Due Total Past Current Total Loans Past Due > December 31, 2016 Commercial real estate: Construction $ — $ — $ — $ — $ 253,302 $ 253,302 $ — Single and multi-family 618 110 624 1,352 190,467 191,819 155 Commercial real estate 481 2,243 4,212 6,936 1,474,287 1,481,223 — Total 1,099 2,353 4,836 8,288 1,918,056 1,926,344 155 Commercial and industrial loans Total 3,090 1,301 6,290 10,681 897,421 908,102 5 Residential mortgages: 1-4 family 1,393 701 4,179 6,273 1,577,521 1,583,794 1,956 Construction 10 — — 10 11,168 11,178 — Total 1,403 701 4,179 6,283 1,588,689 1,594,972 1,956 Consumer loans: Home equity 99 — 2,981 3,080 310,441 313,521 306 Auto and other 2,483 494 968 3,945 474,423 478,368 16 Total 2,582 494 3,949 7,025 784,864 791,889 322 Total $ 8,174 $ 4,849 $ 19,254 $ 32,277 $ 5,189,030 $ 5,221,307 $ 2,438 Acquired Loans (in thousands) 30-59 Days 60-89 Days >90 Days Past Due Total Past Acquired Total Loans Past Due > December 31, 2017 Commercial real estate: Construction $ — $ — $ — $ — $ 7,655 $ 84,965 $ — Single and multi-family 671 — 203 874 2,846 206,082 — Commercial real estate 816 1,875 2,156 4,847 42,801 755,988 109 Total 1,487 1,875 2,359 5,721 53,302 1,047,035 109 Commercial and industrial loans Total 1,252 268 1,439 2,959 34,629 621,370 23 Residential mortgages: 1-4 family 957 2,581 1,247 4,785 6,974 289,373 30 Construction — — — — — 233 — Total 957 2,581 1,247 4,785 6,974 289,606 30 Consumer loans: Home equity 286 40 1,965 2,291 1,956 115,227 — Auto and other 346 135 430 911 483 113,902 38 Total 632 175 2,395 3,202 2,439 229,129 38 Total $ 4,328 $ 4,899 $ 7,440 $ 16,667 $ 97,344 $ 2,187,140 $ 200 Acquired Loans (in thousands) 30-59 Days 60-89 Days >90 Days Past Due Total Past Acquired Total Loans Past Due > December 31, 2016 Commercial real estate: Construction $ — $ — $ — $ — $ 47 $ 34,207 $ — Single and multi-family 2 — 437 439 4,726 125,672 — Commercial real estate 1,555 — 765 2,320 30,047 530,215 — Total 1,557 — 1,202 2,759 34,820 690,094 — Commercial and industrial loans: Total 1,850 15 1,262 3,127 3,369 153,936 24 Residential mortgages: 1-4 family 321 343 2,015 2,679 7,283 297,355 443 Construction — — — — — 804 — Total 321 343 2,015 2,679 7,283 298,159 443 Consumer loans: Home equity 753 — 870 1,623 957 80,279 353 Auto and other 542 314 1,686 2,542 387 106,012 791 Total 1,295 314 2,556 4,165 1,344 186,291 1,144 Total $ 5,023 $ 672 $ 7,035 $ 12,730 $ 46,816 $ 1,328,480 $ 1,611
Summary of Information Pertaining to Non-accrual Loans	The following is summary information pertaining to non-accrual loans at year-end 2017 and 2016: December 31, 2017 December 31, 2016 (In thousands) Business Activities Acquired Loans (1) Total Business Activities Acquired Loans (2) Total Commercial real estate: Construction — — — — — — Single and multi-family 451 203 654 469 437 906 Other commercial real estate 4,566 2,047 6,613 4,212 765 4,977 Total 5,017 2,250 7,267 4,681 1,202 5,883 Commercial and industrial loans: Total 5,895 1,333 7,228 6,285 1,155 7,440 Residential mortgages: 1-4 family $ 1,666 $ 1,217 $ 2,883 $ 2,223 $ 1,572 $ 3,795 Construction — — — — — — Total 1,666 1,217 2,883 2,223 1,572 3,795 Consumer loans: Home equity 1,627 1,965 3,592 2,675 517 3,192 Auto and other 1,454 392 1,846 952 895 1,847 Total 3,081 2,357 5,438 3,627 1,412 5,039 Total non-accrual loans $ 15,659 $ 7,157 $ 22,816 $ 16,816 $ 5,341 $ 22,157 (1) At year-end 2017, acquired credit impaired loans account for $83 thousand of loans greater than 90 days past due that are not presented in the above table. (2) At year-end 2016, acquired credit impaired loans account for $83 thousand of loans greater than 90 days past due that are not presented in the above table.
Schedule of Loans Evaluated for Impairment	Loans evaluated for impairment as of December 31, 2017 and 2016 were as follows: Business Activities Loans (In thousands) Commercial Commercial Residential Consumer Total Loans receivable: Balance at end of year Individually evaluated for impairment $ 33,732 $ 5,761 $ 3,872 $ — $ 43,365 Collectively evaluated 2,183,975 1,176,808 1,809,329 898,721 6,068,833 Total $ 2,217,707 $ 1,182,569 $ 1,813,201 $ 898,721 $ 6,112,198 Business Activities Loans (In thousands) Commercial Commercial Residential Consumer Total Loans receivable: Balance at end of year Individually evaluated for impairment $ 25,549 $ 5,705 $ 2,775 $ 2,703 $ 36,732 Collectively evaluated 1,900,795 902,397 1,592,197 789,186 5,184,575 Total $ 1,926,344 $ 908,102 $ 1,594,972 $ 791,889 $ 5,221,307 Acquired Loans (In thousands) Commercial Commercial Residential Consumer Total Loans receivable: Balance at end of year Individually evaluated for impairment $ 4,244 $ 421 $ 2,617 $ 27 $ 7,309 Purchased credit-impaired loans 53,302 34,629 6,974 2,439 97,344 Collectively evaluated 989,489 586,320 280,015 226,663 2,082,487 Total $ 1,047,035 $ 621,370 $ 289,606 $ 229,129 $ 2,187,140 Acquired Loans (In thousands) Commercial Commercial Residential Consumer Total Loans receivable: Balance at end of year Individually evaluated for impairment $ 4,256 $ 635 $ 308 $ 406 $ 5,605 Purchased credit-impaired loans 34,820 3,369 7,283 1,344 46,816 Collectively evaluated 651,018 149,932 290,568 184,541 1,276,059 Total $ 690,094 $ 153,936 $ 298,159 $ 186,291 $ 1,328,480
Summary of Impaired Loans	The following is a summary of impaired loans at year-end 2017 and 2016 and for the years then ended: Business Activities Loans At December 31, 2017 (In thousands) Recorded Investment (1) Unpaid Principal Related Allowance With no related allowance: Commercial real estate - construction $ — $ — $ — Commercial real estate - single and multifamily 1,077 3,607 — Other commercial real estate 18,285 18,611 — Other commercial and industrial loans 2,060 2,629 — Residential mortgages - 1-4 family 660 1,075 — Consumer - home equity 867 1,504 — With an allowance recorded: Commercial real estate - construction $ 159 $ 159 $ 1 Commercial real estate - single and multifamily 159 171 1 Other commercial real estate 14,321 15,235 227 Other commercial and industrial loans 3,716 4,249 66 Residential mortgages - 1-4 family 1,344 1,446 130 Consumer - home equity 1,014 999 34 Consumer - other 17 17 1 Total Commercial real estate $ 34,001 $ 37,783 $ 229 Commercial and industrial 5,776 6,878 66 Residential mortgages 2,004 2,521 130 Consumer 1,898 2,520 35 Total impaired loans $ 43,679 $ 49,702 $ 460 (1) The Recorded Investment represents the face amount of the loan increased or decreased by applicable accrued interest, net deferred loan fees and costs, and unamortized premium or discount, and reflects direct charge-offs. This amount is a component of total loans on the Consolidated Balance Sheet. (2) The Unpaid Principal Balance represents the customer's legal obligation to the Company. Business Activities Loans At December 31, 2016 (In thousands) Recorded Investment (1) Unpaid Principal Related Allowance With no related allowance: Other commercial real estate $ 18,905 $ 18,905 $ — Other commercial and industrial loans 382 382 — Residential mortgages - 1-4 family 2,101 2,101 — Consumer - home equity 1,605 1,605 — With an allowance recorded: Commercial real estate - single and multifamily $ 179 $ 181 $ 2 Other commercial real estate 6,306 6,462 156 Other commercial and industrial loans 5,060 5,324 264 Residential mortgages - 1-4 family 538 674 136 Consumer - home equity 942 1,098 156 Total Commercial real estate $ 25,390 $ 25,548 $ 158 Commercial and industrial 5,442 5,706 264 Residential mortgages 2,639 2,775 136 Consumer 2,547 2,703 156 Total impaired loans $ 36,018 $ 36,732 $ 714 (1) The Recorded Investment represents the face amount of the loan increased or decreased by applicable accrued interest, net deferred loan fees and costs, and unamortized premium or discount, and reflects direct charge-offs. This amount is a component of total loans on the Consolidated Balance Sheet. (2) The Unpaid Principal Balance represents the customer's legal obligation to the Company. Acquired Loans At December 31, 2017 (In thousands) Recorded Investment (1) Unpaid Principal Related Allowance With no related allowance: Commercial real estate - single and multifamily $ 204 $ 290 $ — Other commercial real estate loans 1,123 2,794 — Other commercial and industrial loans 255 310 — Residential mortgages - 1-4 family 658 671 — Consumer - home equity 1,374 1,654 — Consumer - other 27 27 — With an allowance recorded: Commercial real estate - single and multifamily $ 887 $ 880 $ 18 Other commercial real estate loans 2,043 1,661 38 Other commercial and industrial loans 165 166 1 Residential mortgages - 1-4 family 166 185 9 Consumer - home equity 433 540 45 Total Commercial real estate $ 4,257 $ 5,625 $ 56 Commercial and industrial 420 476 1 Residential mortgages 824 856 9 Consumer 1,834 2,221 45 Total impaired loans $ 7,335 $ 9,178 $ 111 (1) The Recorded Investment represents the face amount of the loan increased or decreased by applicable accrued interest, net deferred loan fees and costs, and unamortized premium or discount, and reflects direct charge-offs. This amount is a component of total loans on the Consolidated Balance Sheet. (2) The Unpaid Principal Balance represents the customer's legal obligation to the Company. Acquired Loans December 31, 2016 (In thousands) Recorded Investment (1) Unpaid Principal Related Allowance With no related allowance: Other commercial real estate loans $ 547 $ 547 $ — Residential mortgages - 1-4 family 208 208 — Consumer - home equity — — — Consumer - other — — — With an allowance recorded: Commercial real estate - single and multifamily $ 1,250 $ 1,358 $ 108 Other commercial real estate loans 2,209 2,351 142 Other Commercial and industrial loans 576 635 59 Residential mortgages - 1-4 family 89 100 11 Consumer - home equity 292 406 114 Total Commercial real estate $ 4,006 $ 4,256 $ 250 Commercial and industrial 576 635 59 Residential mortgages 297 308 11 Consumer 292 406 114 Total impaired loans $ 5,171 $ 5,605 $ 434 (1) The Recorded Investment represents the face amount of the loan increased or decreased by applicable accrued interest, net deferred loan fees and costs, and unamortized premium or discount, and reflects direct charge-offs. This amount is a component of total loans on the Consolidated Balance Sheet. (2) The Unpaid Principal Balance represents the customer's legal obligation to the Company.
Summary of the Average Recorded Investment and Interest Income Recognized on Impaired Loans	The following is a summary of the average recorded investment and interest income recognized on impaired loans as of December 31, 2017, 2016 and 2015: Business Activities Loans December 31, 2017 December 31, 2016 December 31, 2015 (in thousands) Average Recorded Cash Basis Interest Average Recorded Cash Basis Interest Average Recorded Cash Basis Interest With no related allowance: Commercial real estate - construction $ — $ — $ — $ — $ 2,245 $ 92 Commercial real estate - single and multifamily 341 214 36 1 60 — Other commercial real estate 20,867 1,123 6,463 1,155 12,487 302 Other commercial and industrial 4,437 265 3,349 131 3,870 177 Residential mortgages - 1-4 family 1,128 31 2,403 91 1,353 38 Consumer-home equity 1,291 30 612 5 442 13 Consumer-other 72 3 2 — — — With an allowance recorded: Commercial mortgages - construction $ 41 $ 3 $ — $ — $ — $ — Commercial real estate - single and multifamily 169 12 15 6 — — Other commercial real estate 11,372 520 7,576 349 3,214 132 Other commercial and industrial 3,251 267 2,002 225 810 37 Residential mortgages - 1-4 family 1,289 59 682 26 1,704 72 Consumer-home equity 1,007 29 999 35 83 — Consumer - other 4 1 103 4 112 4 Total Commercial real estate $ 32,790 $ 1,872 $ 14,090 $ 1,511 $ 18,006 $ 526 Commercial and industrial 7,688 532 5,351 356 4,680 214 Residential mortgages 2,417 90 3,085 117 3,057 110 Consumer loans 2,374 63 1,716 44 637 17 Total impaired loans $ 45,269 $ 2,557 $ 24,242 $ 2,028 $ 26,380 $ 867 Acquired Loans December 31, 2017 December 31, 2016 December 31, 2015 (in thousands) Average Recorded Cash Basis Interest Average Recorded Cash Basis Interest Average Recorded Cash Basis Interest With no related allowance: Commercial real estate - construction $ — $ — $ — $ — $ 445 $ 60 Commercial real estate - single and multifamily 342 82 — — 2,014 57 Other commercial real estate 487 239 521 20 1,721 37 Other commercial and industrial 581 43 492 9 — — Residential mortgages - 1-4 family 390 28 293 12 463 6 Consumer - home equity 773 22 — — 152 5 Consumer - other 7 1 105 1 59 5 With an allowance recorded: Commercial real estate - construction $ — $ — $ — $ — $ — $ — Commercial real estate - single and multifamily 903 47 1,064 115 623 33 Other commercial real estate 1,719 91 2,618 165 1,384 96 Other commercial and industrial 47 13 369 17 31 3 Residential mortgages - 1-4 family 173 9 214 25 304 9 Consumer - home equity 400 21 — — 195 7 Total Commercial real estate $ 3,451 $ 459 $ 4,203 $ 300 $ 6,187 $ 283 Commercial and industrial 628 56 861 26 31 3 Residential mortgages 563 37 507 37 767 15 Consumer loans 1,180 44 105 1 406 17 Total impaired loans $ 5,822 $ 596 $ 5,676 $ 364 $ 7,391 $ 318
Schedule of Recorded Investment and Number of Modifications for TDRs Identified During the Period	The following tables disclose the recorded investment and number of modifications for TDRs for the prior years where a concession was made and the borrower subsequently defaulted in the respective reporting period. For the year ended 2017, there were three loans that were restructured that had subsequently defaulted during the period. For the period ended 2016, there were no loans that were restructured that had subsequently defaulted during the period. For the year ended 2015, there were eight loans that were restructured that had subsequently defaulted during the period. Modifications that subsequently defaulted for the twelve months ending December 31, 2017 Number of Contracts Recorded Investment Troubled Debt Restructurings Commercial - Single and multifamily — $ — Commercial - Other 1 113 Commercial and industrial - Other 2 492 Residential - 1-4 Family — — 3 $ 605 Modifications that subsequently defaulted for the twelve months ending December 31, 2015 Number of Contracts Recorded Investment Troubled Debt Restructurings Commercial - Single and multifamily 1 $ — Commercial - Other 1 373 Commercial and industrial - Other 4 6,579 Residential - 1-4 Family 2 169 8 $ 7,121 The following tables include the recorded investment and number of modifications for modified loans identified during the years-ended December 31, 2017, 2016, and 2015 respectively. The tables include the recorded investment in the loans prior to a modification and also the recorded investment in the loans after the loans were restructured. The modifications for the year-ended December 31, 2017 were attributable to interest rate concessions, principal concessions, maturity date extensions, modified payment terms, reamortization, and accelerated maturity. The modifications for the year-ended December 31, 2016 were attributable to interest rate concessions, maturity date extensions, modified payment terms, reamortization, and accelerated maturity. Modifications by Class Number of Pre-Modification Post-Modification Troubled Debt Restructurings Commercial - Single and multifamily 1 $ 235 $ 235 Commercial - Other 15 13,445 11,718 Commercial and industrial - Other 12 3,507 3,507 Residential - 1-4 Family 4 331 314 Consumer - Home Equity 3 122 122 35 $ 17,640 $ 15,896 Modifications by Class Number of Pre-Modification Post-Modification Troubled Debt Restructurings Commercial - Single and multifamily 5 $ 437 $ 437 Commercial - Other 5 16,651 16,651 Commercial and industrial - Other 4 555 555 Residential - 1-4 Family 2 5 5 Consumer - Home Equity 1 117 117 17 $ 17,765 $ 17,765 Modifications by Class Number of Pre-Modification Post-Modification Troubled Debt Restructurings Commercial - Construction 1 $ 123 $ 123 Commercial - Single and multifamily 2 307 307 Commercial - Other 4 8,577 7,274 Commercial and industrial - Other 6 9,041 8,904 Consumer - Other 1 999 999 14 $ 19,047 $ 17,607
Schedule of TDR Activity	The following table presents the Company’s TDR activity in 2017 and 2016: (In thousands) 2017 2016 2015 Balance at beginning of year $ 33,829 $ 22,048 $ 16,714 Principal payments (3,213 ) (5,870 ) (5,460 ) TDR status change (1) — 2,235 — Other reductions (2) (4,522 ) (2,349 ) (3,160 ) Newly identified TDRs 15,896 17,765 13,954 Balance at end of year $ 41,990 $ 33,829 $ 22,048 ________________________________ (1) TDR status change classification represents TDR loans with a specified interest rate equal to or greater than the rate that the Company was willing to accept at the time of the restructuring for a new loan with comparable risk and the loan was on current payment status and not impaired based on the terms specified by the restructuring agreement. (2) Other reductions classification consists of transfer to other real estate owned, charge-offs to loans, and other loan sale payoffs.

LOAN LOSS ALLOWANCE (Tables)

LOAN LOSS ALLOWANCE (Tables)	12 Months Ended
	Dec. 31, 2017
Receivables [Abstract]
Schedule of Activity in the Allowance for Loan Losses	Activity in the allowance for loan losses for 2017, 2016, and 2015 was as follows: Business Activities Loans (In thousands) Commercial Commercial Residential Consumer Total Balance at beginning of year $ 16,498 $ 9,447 $ 7,805 $ 5,479 $ 39,229 Charged-off loans 3,875 3,373 806 3,470 11,524 Recoveries on charged-off loans 170 179 270 270 889 Provision for loan losses 4,050 7,597 2,151 3,528 17,326 Balance at end of year $ 16,843 $ 13,850 $ 9,420 $ 5,807 $ 45,920 Individually evaluated for impairment 229 66 130 35 460 Collectively evaluated 16,614 13,784 9,290 5,772 45,460 Total $ 16,843 $ 13,850 $ 9,420 $ 5,807 $ 45,920 Business Activities Loans (In thousands) Commercial real estate Commercial Residential Consumer Total Balance at beginning of year $ 14,591 $ 7,385 $ 7,613 $ 4,985 $ 34,574 Charged-off loans 2,127 4,620 2,036 1,722 10,505 Recoveries on charged-off loans 243 123 159 267 792 Provision for loan losses 3,791 6,559 2,069 1,949 14,368 Balance at end of year $ 16,498 $ 9,447 $ 7,805 $ 5,479 $ 39,229 Individually evaluated for impairment 158 264 136 156 714 Collectively evaluated 16,340 9,183 7,669 5,323 38,515 Total $ 16,498 $ 9,447 $ 7,805 $ 5,479 $ 39,229 Business Activities Loans (In thousands) Commercial Commercial Residential Consumer Total Balance at beginning of year $ 14,740 $ 5,246 $ 6,864 $ 5,945 $ 32,795 Charged-off loans 6,865 2,358 1,215 1,183 11,621 Recoveries on charged-off loans 164 169 141 285 759 Provision for loan losses 6,552 4,328 1,823 (62 ) 12,641 Balance at end of year $ 14,591 $ 7,385 $ 7,613 $ 4,985 $ 34,574 Individually evaluated for impairment 149 21 153 103 426 Collectively evaluated 14,442 7,364 7,460 4,882 34,148 Total $ 14,591 $ 7,385 $ 7,613 $ 4,985 $ 34,574 Acquired Loans (In thousands) Commercial Commercial Residential Consumer Total Balance at beginning of year $ 2,303 $ 1,164 $ 766 $ 536 $ 4,769 Charged-off loans 771 844 797 648 3,060 Recoveries on charged-off loans 65 245 43 153 506 Provision for loan losses 2,259 560 586 294 3,699 Balance at end of year $ 3,856 $ 1,125 $ 598 $ 335 $ 5,914 Individually evaluated for impairment 56 1 9 45 111 Collectively evaluated 3,800 1,124 589 290 5,803 Total $ 3,856 $ 1,125 $ 598 $ 335 $ 5,914 Acquired Loans (In thousands) Commercial Commercial Residential Consumer Total Balance at beginning of year $ 1,903 $ 1,330 $ 976 $ 525 $ 4,734 Charged-off loans 977 1,095 829 620 3,521 Recoveries on charged-off loans 61 266 144 91 562 Provision for loan losses 1,316 663 475 540 2,994 Balance at end of year $ 2,303 $ 1,164 $ 766 $ 536 $ 4,769 Individually evaluated for impairment 250 59 11 114 434 Collectively evaluated 2,053 1,105 755 422 4,335 Total $ 2,303 $ 1,164 $ 766 $ 536 $ 4,769 Acquired Loans (In thousands) Commercial Commercial Residential Consumer Total Balance at beginning of year $ 790 $ 1,093 $ 615 $ 369 $ 2,867 Charged-off loans 681 752 642 992 3,067 Recoveries on charged-off loans 418 289 64 78 849 Provision for loan losses 1,376 700 939 1,070 4,085 Balance at end of year $ 1,903 $ 1,330 $ 976 $ 525 $ 4,734 Individually evaluated for impairment 43 — 30 25 98 Purchased credit-impaired loans 42 — — — 42 Collectively evaluated 1,818 1,330 946 500 4,594 Total $ 1,903 $ 1,330 $ 976 $ 525 $ 4,734
Schedule of Loans by Risk Rating	The following tables present the Company’s loans by risk rating at year-end 2017 and 2016: Business Activities Loans Commercial Real Estate Credit Risk Profile by Creditworthiness Category Construction Single and multi-family Real Estate Total commercial real estate (In thousands) 2017 2016 2017 2016 2017 2016 2017 2016 Grade: Pass $ 181,371 $ 253,302 $ 214,289 $ 189,310 $ 1,775,091 $ 1,434,762 $ 2,170,751 $ 1,877,374 Special mention — — 504 334 12,999 5,827 13,503 6,161 Substandard — — 2,290 2,175 31,163 40,598 33,453 42,773 Doubtful — — — — — 36 — 36 Total $ 181,371 $ 253,302 $ 217,083 $ 191,819 $ 1,819,253 $ 1,481,223 $ 2,217,707 $ 1,926,344 Commercial and Industrial Loans Credit Risk Profile by Creditworthiness Category Total comm. and industrial (In thousands) 2017 2016 Grade: Pass $ 1,156,240 $ 890,974 Special mention 12,806 123 Substandard 11,123 13,825 Doubtful 2,400 3,180 Total $ 1,182,569 $ 908,102 Residential Mortgages Credit Risk Profile by Internally Assigned Grade 1-4 family Construction Total residential mortgages (In thousands) 2017 2016 2017 2016 2017 2016 Grade: Pass $ 1,805,596 $ 1,578,913 $ 5,177 $ 11,178 $ 1,810,773 $ 1,590,091 Special mention 242 701 — — 242 701 Substandard 2,186 4,179 — — 2,186 4,179 Total $ 1,808,024 $ 1,583,793 $ 5,177 $ 11,178 $ 1,813,201 $ 1,594,971 Consumer Loans Credit Risk Profile Based on Payment Activity Home equity Auto and other Total consumer (In thousands) 2017 2016 2017 2016 2017 2016 Performing $ 293,327 $ 310,846 $ 602,313 $ 477,416 $ 895,640 $ 788,262 Nonperforming 1,627 2,675 1,454 952 3,081 3,627 Total $ 294,954 $ 313,521 $ 603,767 $ 478,368 $ 898,721 $ 791,889 Acquired Loans Commercial Real Estate Credit Risk Profile by Creditworthiness Category Construction Single and multi-family Real Estate Total commercial real estate (In thousands) 2017 2016 2017 2016 2017 2016 2017 2016 Grade: Pass $ 76,611 $ 33,461 $ 203,624 $ 119,414 $ 684,846 $ 496,562 $ 965,081 $ 649,437 Special mention — — 603 907 22,070 1,622 22,673 2,529 Substandard 8,354 746 1,855 5,351 49,072 32,031 59,281 38,128 Total $ 84,965 $ 34,207 $ 206,082 $ 125,672 $ 755,988 $ 530,215 $ 1,047,035 $ 690,094 Commercial and Industrial Loans Credit Risk Profile by Creditworthiness Category Total comm. and industrial (In thousands) 2017 2016 Grade: Pass $ 606,922 $ 147,102 Special mention 1,241 1,260 Substandard 13,207 5,574 Total $ 621,370 $ 153,936 Residential Mortgages Credit Risk Profile by Internally Assigned Grade 1-4 family Construction Total residential mortgages (In thousands) 2017 2016 2017 2016 2017 2016 Grade: Pass $ 281,160 $ 294,983 $ 233 $ 804 $ 281,393 $ 295,787 Special mention 2,704 343 — — 2,704 343 Substandard 5,509 2,029 — — 5,509 2,029 Total $ 289,373 $ 297,355 $ 233 $ 804 $ 289,606 $ 298,159 Consumer Loans Credit Risk Profile Based on Payment Activity Home equity Auto and other Total consumer (In thousands) 2017 2016 2017 2016 2017 2016 Performing $ 113,262 $ 79,762 $ 113,510 $ 105,117 $ 226,772 $ 184,879 Nonperforming 1,965 517 392 895 2,357 1,412 Total $ 115,227 $ 80,279 $ 113,902 $ 106,012 $ 229,129 $ 186,291
Summary of Information About Total Loans Rated Special Mention or Lower	The following table summarizes information about total loans rated Special Mention or lower. The table below includes consumer loans that are Special Mention and Substandard accruing that are classified in the above table as performing based on payment activity. December 31, 2017 December 31, 2016 (In thousands) Business Acquired Loans Total Business Acquired Loans Total Non-Accrual $ 15,659 $ 7,240 $ 22,899 $ 16,816 $ 5,424 $ 22,240 Substandard Accruing 36,846 73,412 110,258 51,125 44,177 95,302 Total Classified 52,505 80,652 133,157 67,941 49,601 117,542 Special Mention 28,387 26,802 55,189 7,479 4,323 11,802 Total Criticized $ 80,892 $ 107,454 $ 188,346 $ 75,420 $ 53,924 $ 129,344

PREMISES AND EQUIPMENT (Tables)

PREMISES AND EQUIPMENT (Tables)	12 Months Ended
	Dec. 31, 2017
Property, Plant and Equipment [Abstract]
Summary of Premises and Equipment	Year-end premises and equipment are summarized as follows: (In thousands) 2017 2016 Estimated Useful Land $ 14,177 $ 10,563 N/A Buildings and improvements 99,821 85,319 5 - 39 years Furniture and equipment 49,600 42,693 3 - 7 years Construction in process 5,177 4,084 Premises and equipment, gross 168,775 142,659 Accumulated depreciation and amortization (59,423 ) (49,444 ) Premises and equipment, net $ 109,352 $ 93,215

GOODWILL AND OTHER INTANGIBLES

GOODWILL AND OTHER INTANGIBLES (Tables)	12 Months Ended
	Dec. 31, 2017
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Increase in Goodwill and Goodwill by Reporting Units	The activity impacting goodwill in 2017 and 2016 is as follows: (In thousands) 2017 2016 Balance, beginning of the period $ 403,106 $ 323,943 Goodwill acquired and adjusted: Commerce Bank 116,181 — 44 Business Capital — 15,892 Ronald N. Lazzaro, PC — 5,492 First Choice Bank — 58,036 Adjustments (1) — (257 ) Balance, end of the period $ 519,287 $ 403,106 ______________________________________________________________________________________________________ (1) In 2016, goodwill related to the Hampden and Firestone acquisitions was adjusted since acquisition dates to reflect new information available during the one-year measurement period.
Schedule of Components of Other Intangible Assets	The components of other intangible assets are as follows: (In thousands) Gross Intangible Assets Accumulated Amortization Net Intangible Assets December 31, 2017 Non-maturity deposits (core deposit intangible) $ 66,923 $ (33,024 ) $ 33,899 Insurance contracts 7,558 (7,526 ) 32 All other intangible assets 7,810 (3,445 ) 4,365 Total $ 82,291 $ (43,995 ) $ 38,296 December 31, 2016 Non-maturity deposits (core deposit intangible) $ 44,523 $ (30,099 ) $ 14,424 Insurance contracts 7,558 (7,504 ) 54 All other intangible assets 7,866 (2,899 ) 4,967 Total $ 59,947 $ (40,502 ) $ 19,445

OTHER ASSETS (Tables)

OTHER ASSETS (Tables)	12 Months Ended
	Dec. 31, 2017
Other Assets [Abstract]
Summary of Other Assets	Year-end other assets are summarized as follows: (In thousands) 2017 2016 Capitalized servicing rights $ 16,361 $ 11,524 Accrued interest receivable 33,739 26,113 Accrued federal and state tax receivable (1) 33,101 19,076 Derivative assets 19,308 21,617 Assets held for sale 1,392 — Other 13,182 20,127 Total other assets $ 117,083 $ 98,457 (1) Accrued federal and state tax receivable as of December 31, 2017 includes $4.3 million of New York State refundable tax credits from investment in historical tax credit partnerships in New York State. This balance was $5.9 million at year-end 2016.
Schedule of Mortgage Servicing Rights Activity	Servicing rights activity was as follows: (In thousands) 2017 2016 Balance at beginning of year $ 11,524 $ 5,187 Acquired from 44 Business Capital — 3,489 Acquired from First Choice Bank (1) — 696 Additions 7,604 4,116 Amortization (2,446 ) (1,964 ) Change in fair value (221 ) — Allowance adjustment (100 ) — Balance at end of year $ 16,361 $ 11,524 (1) Amounts acquired from First Choice Bank are accounted for at fair value. The balance as of December 31, 2017 and December 31, 2016 were $3.8 million and $0.8 million , respectively.

DEPOSITS (Tables)

DEPOSITS (Tables)	12 Months Ended
	Dec. 31, 2017
Deposits [Abstract]
Summary of Time Deposits	A summary of year-end time deposits is as follows: (In thousands) 2017 2016 Maturity date: Within 1 year $ 1,790,056 $ 1,316,973 Over 1 year to 2 years 546,381 582,764 Over 2 years to 3 years 268,897 142,160 Over 3 years to 4 years 161,314 150,388 Over 4 years to 5 years 121,400 137,845 Over 5 years 2,157 3,413 Total $ 2,890,205 $ 2,333,543 Account balances: Less than $100,000 $ 733,785 $ 656,055 $100,000 or more 2,156,420 1,677,488 Total $ 2,890,205 $ 2,333,543

BORROWED FUNDS (Tables)

BORROWED FUNDS (Tables)	12 Months Ended
	Dec. 31, 2017
Debt Disclosure [Abstract]
Schedule of Borrowed Funds	Borrowed funds at December 31, 2017 and 2016 are summarized, as follows: 2017 2016 (in thousands, except rates) Principal Weighted Principal Weighted Short-term borrowings: Advances from the FHLBB $ 667,300 1.48 % $ 1,072,044 0.71 % Other Borrowings — — 10,000 2.42 Total short-term borrowings: 667,300 1.48 1,082,044 0.72 Long-term borrowings: Advances from the FHLBB 380,436 1.54 142,792 1.53 Subordinated notes 73,875 7.00 73,697 7.00 Junior subordinated notes 15,464 3.30 15,464 2.77 Total long-term borrowings: 469,775 2.46 231,953 3.35 Total $ 1,137,075 1.88 % $ 1,313,997 1.19 %
Summary of Maturities of FHLBB Advances	A summary of maturities of FHLBB advances at year-end 2017 is as follows: 2017 (In thousands) Amount Weighted Fixed rate advances maturing: 2018 $ 836,115 1.43 % 2019 150,082 1.64 2020 54,101 2.04 2021 220 3.21 2022 and beyond 7,218 2.64 Total fixed rate advances $ 1,047,736 1.50 Total FHLBB advances $ 1,047,736 1.50 %

OTHER LIABILITIES (Tables)

OTHER LIABILITIES (Tables)	12 Months Ended
	Dec. 31, 2017
Other Liabilities Disclosure [Abstract]
Summary of other liabilities	Year-end other liabilities are summarized as follows: December 31, (In thousands) 2017 2016 Derivative liabilities $ 15,838 $ 24,420 Capital lease obligation 11,323 11,639 Asset purchase settlement payable 70,637 29,158 Employee benefits liability 27,093 17,972 Level lease liability 5,766 6,997 Accrued interest payable 6,813 4,394 Customer transaction clearing accounts 9,118 1,786 Other 41,294 36,789 Total other liabilities $ 187,882 $ 133,155

EMPLOYEE BENEFIT PLANS (Tables)

EMPLOYEE BENEFIT PLANS (Tables)	12 Months Ended
	Dec. 31, 2017
Retirement Benefits [Abstract]
Schedule of changes in the Projected Benefit Obligation and Plan Assets	Information regarding the post-retirement plan is as follows: December 31, (In thousands) 2017 2016 Change in accumulated postretirement benefit obligation: Accumulated post-retirement benefit obligation at beginning of year $ 3,249 $ 3,039 Service Cost 35 32 Interest cost 131 129 Participant contributions 46 47 Actuarial loss (gain) 326 130 Benefits paid (94 ) (128 ) Accumulated post-retirement benefit obligation at end of year $ 3,693 $ 3,249 Change in plan assets: Fair value of plan assets at beginning of year $ — $ — Contributions by employer 48 81 Contributions by participant 46 47 Benefits paid (94 ) (128 ) Fair value of plan assets at end of year $ — $ — Information regarding the pension plan is as follows: December 31, (In thousands) 2017 2016 Change in projected benefit obligation: Projected benefit obligation at beginning of year $ 6,126 $ 6,585 Service Cost 66 76 Interest cost 237 267 Actuarial gain 309 (308 ) Benefits paid (324 ) (318 ) Settlements (61 ) (176 ) Projected benefit obligation at end of year 6,353 6,126 Accumulated benefit obligation 6,353 6,126 Change in fair value of plan assets: Fair value of plan assets at plan beginning of year 5,121 5,211 Actual return on plan assets 710 404 Benefits paid (324 ) (318 ) Settlements (61 ) (176 ) Fair value of plan assets at end of year 5,446 5,121 Underfunded status $ 907 $ 1,005
Schedule of Amounts Recognized in Statement of Financial Position	Amounts Recognized in Consolidated Balance Sheet Other Liabilities $ 3,693 $ 3,249 Amounts Recognized in Consolidated Balance Sheet Other Liabilities $ 907 $ 1,005
Schedule of Net Periodic Cost	Net periodic post-retirement cost is comprised of the following: December 31, (In thousands) 2017 2016 Service cost $ 35 $ 32 Interest costs 131 129 Amortization of net prior service credit 83 83 Amortization of net actuarial loss — — Net periodic post-retirement costs $ 249 $ 244 Net periodic pension cost is comprised of the following: December 31, (In thousands) 2017 2016 Service Cost $ 66 $ 76 Interest Cost 237 267 Expected return on plan assets (346 ) (361 ) Amortization of unrecognized actuarial loss 100 163 Net periodic pension costs $ 57 $ 145
Schedule of Changes in Plan Assets and Benefit Obligations Recognized in Accumulated Other Comprehensive Income	Changes in plan assets and benefit obligations recognized in accumulated other comprehensive income are as follows: December 31, (In thousands) 2017 2016 Amortization of actuarial (loss) $ (100 ) $ (163 ) Actuarial (gain) loss (54 ) (351 ) Total recognized in accumulated other comprehensive income (154 ) (514 ) Total recognized in net periodic pension cost recognized and other comprehensive income $ (97 ) $ (369 ) Changes in benefit obligations recognized in accumulated other comprehensive income are as follows: December 31, (In thousands) 2017 2016 Amortization of actuarial loss $ — $ — Amortization of prior service credit (83 ) (83 ) Net actuarial (gain) loss 199 (126 ) Total recognized in accumulated other comprehensive income 116 (209 ) Accrued post-retirement liability recognized $ 1,918 $ 1,718
Schedule of Principal Actuarial Assumptions	The principal actuarial assumptions used were as follows: December 31, 2017 2016 Projected benefit obligation Discount rate 3.510 % 3.980 % Net periodic pension cost Discount rate 3.980 % 4.170 % Long term rate of return on plan assets 7.000 % 7.000 %
Schedule of Fair Values of the Plan's Assets by Asset Category and Level Within the Fair Value Hierarchy	The fair values of the Plan’s assets by category and level within the fair value hierarchy are as follows at December 31, 2017: December 31, 2017 Asset Category (In thousands) Total Level 1 Level 2 Equity Mutual Funds: Large-Cap $ 1,820 $ — $ 1,820 Mid-Cap 439 — 439 Small-Cap 438 — 438 International 893 — 893 Fixed Income Funds Fixed Income - US Core 1,308 — 1,308 Intermediate Duration 437 — 437 Cash Equivalents - money market 111 29 82 Total $ 5,446 $ 29 $ 5,417 The fair values of the Plan’s assets by category and level within the fair value hierarchy are as follows at December 31, 2016: December 31, 2016 Asset Category (In thousands) Total Level 1 Level 2 Equity Mutual Funds: Large-Cap $ 1,624 $ — $ 1,624 Mid-Cap 401 — 401 Small-Cap 415 — 415 International 757 — 757 Fixed Income Funds Fixed Income - US Core 1,378 — 1,378 Intermediate Duration 472 — 472 Cash Equivalents - money market 74 30 44 Total $ 5,121 $ 30 $ 5,091
Schedule of Estimated Benefit Payments	Estimated benefit payments under the Company’s pension plans over the next ten years at December 31, 2017 are as follows: Year Payments (In thousands) 2018 343 2019 380 2020 372 2021 361 2022 386 2023 - 2027 1,792 Estimated benefit payments under the post-retirement benefit plan over the next ten years at December 31, 2017 are as follows: Year Payments (In thousands) 2018 103 2019 103 2020 102 2021 106 2022 109 2023 - 2027 548
Schedule of Amounts in Accumulated Other Comprehensive Income That Have Not Yet Been Recognized as Components of Net Periodic Benefit Cost	The amounts in accumulated other comprehensive income that have not yet been recognized as components of net periodic benefit cost are as follows: December 31, (In thousands) 2017 2016 Net prior service cost (credit) $ 1,576 $ 1,659 Net actuarial (gain) loss 199 (126 ) Total recognized in accumulated other comprehensive income $ 1,775 $ 1,533

INCOME TAXES (Tables)

INCOME TAXES (Tables)	12 Months Ended
	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Schedule of Components of Provision for Income Tax Expense	The components of the Company’s provision for income taxes for the years ended December 31, 2017, 2016, and 2015 were, as follows: (In thousands) 2017 2016 2015 Current: Federal tax expense $ 11,686 $ 6,758 $ 4,696 State tax expense 1,112 1,101 (1,631 ) Total current expense 12,798 7,859 3,065 Deferred: Federal tax expense 29,824 9,438 2,023 State tax expense 1,805 1,591 (24 ) Total deferred tax expense (1) 31,629 11,029 1,999 Change in valuation allowance 75 (104 ) — Total income tax expense $ 44,502 $ 18,784 $ 5,064 (1) 2017 Deferred tax expense of $31.6 million includes an $18.1 million charge to re-measure the net deferred tax asset at December 31, 2017 pursuant to the reduction in the corporate income tax rate from 35% to 21%, effective January 1, 2018, per the Tax Cuts and Jobs Act enacted on December 22, 2017.
Schedule of Reconciliation of the Statutory Federal Income Tax Rate to Effective Tax Rate	The following is a reconciliation of the statutory federal income tax rate to the Company’s effective tax rate for the years ended December 31, 2017, 2016, and 2015: 2017 2016 2015 (In thousands, except rates) Amount Rate Amount Rate Amount Rate Statutory tax rate $ 34,912 35.0 % $ 27,108 35.0 % $ 19,104 35.0 % Increase (decrease) resulting from: State taxes, net of federal tax benefit 2,232 2.2 1,675 2.2 (974 ) (1.8 ) Tax exempt income - investments, net (5,395 ) (5.4 ) (3,849 ) (5.0 ) (3,463 ) (6.3 ) Bank-owned life insurance (1,556 ) (1.6 ) (1,364 ) (1.8 ) (1,284 ) (2.4 ) Non-deductible merger costs 368 0.4 542 0.7 422 0.8 Non-deductible goodwill on disposal operations sale — — — — 313 0.6 Tax credits, net of basis reduction (4,656 ) (4.7 ) (6,225 ) (8.0 ) (8,308 ) (15.2 ) Change in valuation allowance 75 0.1 125 0.2 — — Impact of federal tax reform enactment 18,145 18.2 — — — — Other, net 377 0.4 772 1.0 (746 ) (1.4 ) Effective tax rate $ 44,502 44.6 % $ 18,784 24.3 % $ 5,064 9.3 %
Schedule of Components of Deferred Tax Assets and Liabilities	As of December 31, 2017 and 2016, significant components of the Company’s deferred tax assets and liabilities were, as follows: (In thousands) 2017 2016 Deferred tax assets: Allowance for loan losses $ 14,578 $ 17,747 Tax credit carryforwards 4,100 4,100 Unrealized capital loss on tax credit investments 6,502 6,999 Employee benefit plans 4,983 7,813 Purchase accounting adjustments 37,843 23,520 Net operating loss carryforwards 1,374 2,643 Other 2,332 4,997 Deferred tax assets, net before valuation allowances 71,712 67,819 Valuation allowance (200 ) (125 ) Deferred tax assets, net of valuation allowances $ 71,512 $ 67,694 Deferred tax liabilities: Net unrealized gain on swaps, securities available for sale, and pension in OCI $ (1,888 ) $ (5,884 ) Premises and equipment (1,126 ) (2,519 ) Loan servicing rights (2,174 ) (4,546 ) Deferred loan fees (3,900 ) — Intangible amortization (15,001 ) (11,543 ) Other (362 ) (2,074 ) Deferred tax liabilities $ (24,451 ) $ (26,566 ) Deferred tax assets, net $ 47,061 $ 41,128
Schedule of Components of the Valuation Allowance on Deferred Tax Asset	The components of the Company’s valuation allowance on its deferred tax asset, net as of December 31, 2017 and 2016 were, as follows: (in thousands) 2017 2016 State tax basis difference, net of Federal tax benefit $ (200 ) $ (125 ) Valuation allowances $ (200 ) $ (125 )
Schedule of Changes in Unrecognized Tax Benefits	The following table presents changes in unrecognized tax benefits for the years ended December 31, 2017, 2016, and 2015: (In thousands) 2017 2016 2015 Unrecognized tax benefits at January 1 $ 460 $ 307 $ 553 Increase in gross amounts of tax positions related to prior years — 270 — Decrease in gross amounts of tax positions related to prior years (156 ) — — Decrease due to settlement with taxing authority — — — Increase in gross amounts of tax positions related to current year — — — Decrease due to lapse in statute of limitations — (117 ) (246 ) Unrecognized tax benefits at December 31 $ 304 $ 460 $ 307

DERIVATIVE INSTRUMENTS AND HE46

DERIVATIVE INSTRUMENTS AND HEDGING ACTIVITIES (Tables)	12 Months Ended
	Dec. 31, 2017
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of Interest Rate Swap Agreements and Non-hedging Derivative Assets and Liabilities	Information about interest rate swap agreements and non-hedging derivative assets and liabilities at December 31, 2017 follows: Notional Amount Weighted Average Maturity Weighted Average Rate Estimated Fair Value Asset (Liability) December 31, 2017 Received Contract pay rate (In thousands) (In years) (In thousands) Cash flow hedges: Interest rate swaps on FHLBB borrowings $ — 0 — % — % $ — Total cash flow hedges — — Economic hedges: Interest rate swap on tax advantaged economic development bond 10,755 11.9 1.73 % 5.09 % (1,649 ) Interest rate swaps on loans with commercial loan customers 943,795 5.9 3.26 % 4.25 % (3,195 ) Reverse interest rate swaps on loans with commercial loan customers 943,795 5.9 4.25 % 3.26 % 3,204 Risk participation agreements with dealer banks 142,054 8.4 (26 ) Forward sale commitments 276,572 0.2 (123 ) Total economic hedges 2,316,971 (1,789 ) Non-hedging derivatives: Commitments to lend 193,966 0.2 5,259 Total non-hedging derivatives 193,966 5,259 Total $ 2,510,937 $ 3,470 Information about interest rate swap agreements and non-hedging derivative asset and liabilities at December 31, 2016 follows: Notional Amount Weighted Average Maturity Weighted Average Rate Estimated Fair Value Asset (Liability) December 31, 2016 Received Contract pay rate (In thousands) (In years) (In thousands) Cash flow hedges: Forward-starting interest rate swaps on FHLBB borrowings $ 300,000 2.3 0.63 % 2.29 % $ (6,573 ) Total cash flow hedges 300,000 (6,573 ) Economic hedges: Interest rate swap on tax advantaged economic development bond 11,386 12.9 0.98 % 5.09 % (2,021 ) Interest rate swaps on loans with commercial loan customers 668,541 6.2 2.43 % 4.21 % (6,752 ) Reverse interest rate swaps on loans with commercial loan customers 668,541 6.2 4.21 % 2.43 % 7,077 Risk participation agreements with dealer banks 83,360 11.6 5 Forward sale commitments 259,889 0.2 722 Total economic hedges 1,691,717 (969 ) Non-hedging derivatives: Commitments to lend 208,145 0.2 4,738 Total non-hedging derivatives 208,145 4,738 Total $ 2,199,862 $ (2,804 )
Schedule of Amounts Included in the Consolidated Statements of income and in Other Comprehensive Income	Amounts included in the Consolidated Statements of Income and in the other comprehensive income section of the Consolidated Statements of Comprehensive Income (related to interest rate derivatives designated as hedges of cash flows), were as follows: Years Ended December 31, (In thousands) 2017 2016 2015 Interest rate swaps on FHLBB borrowings: Unrealized (loss) recognized in accumulated other comprehensive loss $ (449 ) $ (2,023 ) $ (5,232 ) Less: Reclassification of unrealized (loss) from accumulated other comprehensive loss to interest expense (393 ) (3,981 ) — Less: reclassification of unrealized (loss) from accumulated other (6,629 ) — — Net tax effect on items recognized in accumulated other comprehensive income (2,589 ) (835 ) 2,094 Other comprehensive income recorded in accumulated other comprehensive income, net of reclassification adjustments and tax effects $ 3,984 $ 1,123 $ (3,138 )
Schedule of Amounts Included in the Consolidated Statements of Income Related to Economic Hedges and Non-hedging Derivatives	Amounts included in the Consolidated Statements of Income related to economic hedges and non-hedging derivatives were as follows: Years Ended December 31, (In thousands) 2017 2016 2015 Economic hedges Interest rate swap on industrial revenue bond: Unrealized gain (loss) recognized in other non-interest income $ 371 $ (75 ) $ (344 ) Interest rate swaps on loans with commercial loan customers: Unrealized gain recognized in other non-interest income 3,557 1,312 (4,852 ) Reverse interest rate swaps on loans with commercial loan customers: Unrealized (loss) recognized in other non-interest income (3,557 ) (1,312 ) 4,852 (Unfavorable) Favorable change in credit valuation adjustment recognized in other non-interest income (316 ) 338 (51 ) Risk Participation Agreements: Unrealized (loss) recognized in other non-interest income (31 ) (61 ) (36 ) Forward Commitments: Unrealized gain (loss) recognized in non-interest income (123 ) (1,176 ) (247 ) Realized (loss) in non-interest income (1,764 ) (3,705 ) 45 Non-hedging derivatives Commitments to lend: Unrealized gain recognized in non-interest income $ 5,259 $ 8,373 $ 2,436 Realized gain in non-interest income 50,879 3,650 1,899
Schedule of Assets Subject to an Enforceable Master Netting Arrangement	The following table presents the assets and liabilities subject to an enforceable master netting arrangement as of December 31, 2017 and December 31, 2016 : Offsetting of Financial Assets and Derivative Assets Gross Gross Amounts Net Amounts of Assets Gross Amounts Not Offset in the Statements Financial Cash (in thousands) Net Amount As of December 31, 2017 Interest Rate Swap Agreements: Institutional counterparties $ 2,692 $ (1,622 ) $ 1,070 $ — $ — $ 1,070 Commercial counterparties 8,577 — 8,577 — — 8,577 Total $ 11,269 $ (1,622 ) $ 9,647 $ — $ — $ 9,647 Offsetting of Financial Assets and Derivative Assets Gross Gross Amounts Net Amounts of Assets Gross Amounts Not Offset in the Statements Financial Cash (in thousands) Net Amount As of December 31, 2016 Interest Rate Swap Agreements: Institutional counterparties $ 49 $ — $ 49 $ — $ — $ 49 Commercial counterparties 11,461 — 11,461 — — 11,461 Total $ 11,510 $ — $ 11,510 $ — $ — $ 11,510
Schedule of Liabilities Subject to an Enforceable Master Netting Arrangement	Offsetting of Financial Liabilities and Derivative Liabilities Gross Gross Amounts Net Amounts of Liabilities Gross Amounts Not Offset in the Statements Financial Cash (in thousands) Net Amount As of December 31, 2017 Interest Rate Swap Agreements: Institutional counterparties $ (8,777 ) $ 2,835 $ (5,942 ) $ 3,982 $ 1,960 $ — Commercial counterparties (5,375 ) 2 (5,373 ) — — (5,373 ) Total $ (14,152 ) $ 2,837 $ (11,315 ) $ 3,982 $ 1,960 $ (5,373 ) Offsetting of Financial Liabilities and Derivative Liabilities Gross Gross Amounts Net Amounts of Liabilities Gross Amounts Not Offset in the Statements Financial Cash (in thousands) Net Amount As of December 31, 2016 Interest Rate Swap Agreements: Institutional counterparties $ (20,077 ) $ 4,689 $ (15,388 ) $ 14,738 $ 650 $ — Commercial counterparties (4,407 ) 23 (4,384 ) — — (4,384 ) Total $ (24,484 ) $ 4,712 $ (19,772 ) $ 14,738 $ 650 $ (4,384 )

OTHER COMMITMENTS, CONTINGENC47

OTHER COMMITMENTS, CONTINGENCIES, AND OFF-BALANCE SHEET ACTIVITIES (Tables)	12 Months Ended
	Dec. 31, 2017
Commitments and Contingencies Disclosure [Abstract]
Summary of Financial Instruments Outstanding Whose Contract Amounts Represent Credit Risk	A summary of financial instruments outstanding whose contract amounts represent credit risk is as follows at year-end: (In thousands) 2017 2016 Commitments to originate new loans $ 244,252 $ 243,519 Unused funds on commercial and other lines of credit 678,567 574,043 Unadvanced funds on home equity lines of credit 297,367 281,621 Unadvanced funds on construction and real estate loans 360,472 320,635 Standby letters of credit 13,613 14,939 Lease obligation 11,323 11,639 Total $ 1,605,594 $ 1,446,396

SHAREHOLDERS' EQUITY AND EARN48

SHAREHOLDERS' EQUITY AND EARNINGS PER COMMON SHARE (Tables)	12 Months Ended
	Dec. 31, 2017
Stockholders' Equity Note [Abstract]
Schedule of Actual and Required Capital Ratios	The Company and Bank’s actual and required capital amounts were as follows: Minimum Capital Requirement Minimum to be Well Capitalized Under Prompt Corrective Action Provisions Actual (Dollars in thousands) Amount Ratio Amount Ratio Amount Ratio December 31, 2017 Company (Consolidated) Total capital to risk-weighted assets $ 1,063,843 12.43 % $ 684,692 8.00 % $ 855,865 N/A Common Equity Tier 1 Capital to risk weighted assets 942,389 11.01 385,139 4.50 556,312 N/A Tier 1 capital to risk-weighted assets 954,103 11.15 513,519 6.00 684,692 N/A Tier 1 capital to average assets 954,103 9.01 342,346 4.00 427,932 N/A Bank Total capital to risk-weighted assets $ 954,172 11.17 % $ 683,103 8.00 % $ 853,879 10.00 % Common Equity Tier 1 Capital to risk weighted assets 881,324 10.32 384,245 4.50 555,021 6.50 Tier 1 capital to risk-weighted assets 881,324 10.32 512,327 6.00 683,103 8.00 Tier 1 capital to average assets 881,324 8.32 341,552 4.00 426,939 5.00 December 31, 2016 Company (Consolidated) Total capital to risk-weighted assets $ 803,618 11.87 % $ 541,603 8.00 % $ 677,004 N/A Common Equity Tier 1 Capital to risk weighted assets 670,120 9.90 304,652 4.50 440,053 N/A Tier 1 capital to risk-weighted assets 681,500 10.07 406,202 6.00 541,603 N/A Tier 1 capital to average assets 681,500 7.88 270,802 4.00 338,502 N/A Bank Total capital to risk-weighted assets $ 756,792 11.21 % $ 539,893 8.00 % $ 674,866 10.00 % Common Equity Tier 1 Capital to risk weighted assets 672,244 9.96 303,690 4.50 438,663 6.50 Tier 1 capital to risk-weighted assets 672,244 9.96 404,920 6.00 539,893 8.00 Tier 1 capital to average assets 672,244 7.84 269,920 4.00 337,433 5.00
Schedule of Components of Accumulated Other Comprehensive Loss	Year-end components of accumulated other comprehensive income/(loss) are as follows: (In thousands) 2017 2016 Other accumulated comprehensive income/(loss), before tax: Net unrealized holding gain on AFS securities $ 10,034 $ 25,176 Net (loss) on effective cash flow hedging derivatives — (6,573 ) Net unrealized holding (loss) on pension plans (3,048 ) (2,954 ) Income taxes related to items of accumulated other comprehensive income/(loss): Net unrealized holding (gain) on AFS securities (4,026 ) (9,636 ) Net loss on effective cash flow hedging derivatives — 2,589 Net unrealized holding loss on pension plans 1,201 1,164 Accumulated other comprehensive income/(loss) $ 4,161 $ 9,766
Schedule of Components of Other Comprehensive Loss	The following table presents the components of other comprehensive income (loss) for the years ended December 31, 2017, 2016, and 2015: (In thousands) Before Tax Tax Effect Net of Tax Year Ended December 31, 2017 Net unrealized holding gain on AFS securities: Net unrealized (loss) arising during the period $ (2,544 ) $ 1,075 $ (1,469 ) Less: reclassification adjustment for gains realized in net income 12,598 (4,535 ) 8,063 Net unrealized holding (loss) on AFS securities (15,142 ) 5,610 (9,532 ) Net loss on cash flow hedging derivatives: Net unrealized (loss) arising during the period (449 ) 180 (269 ) Less: reclassification adjustment for (losses) realized in net income (7,022 ) 2,769 (4,253 ) Net gain on cash flow hedging derivatives 6,573 (2,589 ) 3,984 Net unrealized holding (loss) on pension plans Net unrealized (loss) arising during the period (311 ) 124 (187 ) Less: reclassification adjustment for losses realized in net income (217 ) 87 (130 ) Net unrealized holding (loss) on pension plans (94 ) 37 (57 ) Other Comprehensive Income(Loss) $ (8,663 ) $ 3,058 $ (5,605 ) (In thousands) Before Tax Tax Effect Net of Tax Year Ended December 31, 2016 Net unrealized holding gain on AFS securities: Net unrealized gain arising during the period $ 18,308 $ (6,979 ) $ 11,329 Less: reclassification adjustment for (losses) realized in net income (551 ) 220 (331 ) Net unrealized holding gain on AFS securities 18,859 (7,199 ) 11,660 Net (loss) on cash flow hedging derivatives: Net unrealized (loss) arising during the period (2,022 ) 754 (1,268 ) Less: reclassification adjustment for (losses) realized in net income (3,981 ) 1,589 (2,392 ) Net gain on cash flow hedging derivatives 1,959 (835 ) 1,124 Net unrealized holding gain on pension plans Net unrealized gain arising during the period 351 (155 ) 196 Less: reclassification adjustment for (losses) realized in net income (164 ) 73 (91 ) Net unrealized holding gain on pension plans 515 (228 ) 287 Other Comprehensive Income $ 21,333 $ (8,262 ) $ 13,071 (In thousands) Before Tax Tax Effect Net of Tax Year Ended December 31, 2015 Net unrealized holding gain on AFS securities: Net unrealized loss arising during the period $ (7,567 ) $ 2,793 $ (4,774 ) Less: reclassification adjustment for gains realized in net income 2,110 (847 ) 1,263 Net unrealized holding loss on AFS securities (9,677 ) 3,640 (6,037 ) Net (loss) on cash flow hedging derivatives: Net unrealized (loss) arising during the period (5,232 ) 2,094 (3,138 ) Less: reclassification adjustment for (losses) realized in net income — — — Net (loss) on cash flow hedging derivatives (5,232 ) 2,094 (3,138 ) Net unrealized holding (loss) on pension plans Net unrealized (loss) arising during the period (1,436 ) 572 (864 ) Less: reclassification adjustment for (losses) realized in net income (259 ) 104 (155 ) Net unrealized holding (loss) on pension plans (1,177 ) 468 (709 ) Other Comprehensive Loss $ (16,086 ) $ 6,202 $ (9,884 )
Schedule of Gross Changes in Each Component of Accumulated Other Comprehensive Income	The following table presents the changes in each component of accumulated other comprehensive income (loss), for the years ended December 31, 2017 , 2016 , and 2015: (in thousands) Net unrealized holding gain (loss) on AFS Securities Net loss on effective cash flow hedging derivatives Net unrealized holding gain (loss) on pension plans Total Year Ended December 31, 2017 Balance at Beginning of Year $ 15,540 $ (3,984 ) $ (1,790 ) $ 9,766 Other comprehensive gain (loss) before reclassifications (1,469 ) (269 ) (187 ) (1,925 ) Amounts reclassified from accumulated other comprehensive income 8,063 (4,253 ) (130 ) 3,680 Total Other Comprehensive (Loss) Income (9,532 ) 3,984 (57 ) (5,605 ) Balance at End of Period $ 6,008 $ — $ (1,847 ) $ 4,161 Year Ended December 31, 2016 Balance at Beginning of Year $ 3,880 $ (5,108 ) $ (2,077 ) $ (3,305 ) Other comprehensive gain (loss) before reclassifications 11,329 (1,268 ) 196 10,257 Amounts reclassified from accumulated other comprehensive income (331 ) (2,392 ) (91 ) (2,814 ) Total Other Comprehensive Income 11,660 1,124 287 13,071 Balance at End of Period $ 15,540 $ (3,984 ) $ (1,790 ) $ 9,766 Year Ended December 31, 2015 Balance at Beginning of Year $ 9,916 $ (1,969 ) $ (1,368 ) $ 6,579 Other comprehensive gain (loss) Before reclassifications (4,774 ) (3,138 ) (864 ) (8,776 ) Amounts reclassified from accumulated other comprehensive income 1,263 — (155 ) 1,108 Total Other Comprehensive (Loss) (6,037 ) (3,138 ) (709 ) (9,884 ) Balance at End of Period $ 3,880 $ (5,108 ) $ (2,077 ) $ (3,305 )
Schedule of Amounts Reclassified out of Each Component of Accumulated Other Comprehensive Income	The following table presents the amounts reclassified out of each component of accumulated other comprehensive income (loss) for the years ended December 31, 2017 , 2016 , and 2015: Affected Line Item in the Years Ended December 31, (in thousands) 2017 2016 2015 Realized (losses) gains on AFS securities: $ 12,598 $ (551 ) $ 2,110 Non-interest income (4,535 ) 220 (847 ) Tax expense 8,063 (331 ) 1,263 Realized (losses) on cash flow hedging derivatives: (393 ) — — Interest expense (6,629 ) — — Non-interest income — (3,981 ) — Non-interest expense 2,769 1,589 — Tax benefit (4,253 ) (2,392 ) — Realized (losses) on pension plans (217 ) (164 ) (259 ) Non-interest expense 87 73 104 Tax expense (130 ) (91 ) (155 ) Total reclassifications for the period $ 3,680 $ (2,814 ) $ 1,108
Schedule of Earnings Per Share	Earnings per common share has been computed based on the following (average diluted shares outstanding is calculated using the treasury stock method): Years Ended December 31, (In thousands, except per share data) 2017 2016 2015 Net income $ 55,247 $ 58,670 $ 49,518 Average number of common shares issued 40,627 32,604 30,074 Less: average number of treasury shares 963 1,116 1,215 Less: average number of unvested stock award shares 437 500 466 Plus: average participating preferred shares 229 — — Average number of basic common shares outstanding 39,456 30,988 28,393 Plus: dilutive effect of unvested stock award shares 202 122 106 Plus: dilutive effect of stock options outstanding 37 57 65 Average number of diluted common shares outstanding 39,695 31,167 28,564 Basic earning per common share $ 1.40 $ 1.89 $ 1.74 Diluted earnings per common share $ 1.39 $ 1.88 $ 1.73

STOCK-BASED COMPENSATION PLANS

STOCK-BASED COMPENSATION PLANS (Tables)	12 Months Ended
	Dec. 31, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Summary of Activity in the Stock Award and Stock Option Plans	A summary of activity in the Company’s stock compensation plans is shown below: Non-vested Stock Stock Options Outstanding (Shares in thousands) Number of Shares Weighted- Average Number of Shares Weighted- Average Exercise Price Balance, December 31, 2016 448 $ 26.28 109 $ 15.72 Granted 161 35.84 — — Stock options exercised — — (19 ) 17.74 Stock awards vested (174 ) 25.68 — — Forfeited (17 ) 30.04 — — Expired — — (14 ) 29.35 Balance, December 31, 2017 418 $ 29.68 76 $ 13.59

FAIR VALUE MEASUREMENTS (Tables

FAIR VALUE MEASUREMENTS (Tables)	12 Months Ended
	Dec. 31, 2017
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Summary of assets and financial liabilities measured at fair value on a recurring basis segregated by the level of the valuation inputs within the fair value hierarchy utilized to measure fair value	The following table summarizes assets and liabilities measured at fair value on a recurring basis as of year-end 2017 and 2016 segregated by the level of the valuation inputs within the fair value hierarchy utilized to measure fair value: December 31, 2017 (In thousands) Level 1 Level 2 Level 3 Total Trading security $ — $ — $ 12,277 $ 12,277 Available-for-sale securities: Municipal bonds and obligations — 118,233 — 118,233 Agency collateralized mortgage obligations — 851,158 — 851,158 Agency residential mortgage-backed securities — 216,940 — 216,940 Agency commercial mortgage-backed securities — 62,305 — 62,305 Corporate bonds — 110,721 — 110,721 Trust preferred securities — 11,677 — 11,677 Other bonds and obligations — 9,880 — 9,880 Marketable equity securities 44,851 334 — 45,185 Loans held for sale — 153,620 — 153,620 Derivative assets — 14,049 5,259 19,308 Other assets — — 3,834 3,834 Derivative liabilities 104 15,715 19 15,838 December 31, 2016 (In thousands) Level 1 Level 2 Level 3 Total Trading security $ — $ — $ 13,229 $ 13,229 Available-for-sale securities: Municipal bonds and obligations — 119,816 — 119,816 Agency collateralized mortgage obligations — 651,911 — 651,911 Agency residential mortgage-backed securities — 228,684 — 228,684 Agency commercial mortgage-backed securities — 64,534 — 64,534 Corporate bonds — 56,006 — 56,006 Trust preferred securities — 11,887 — 11,887 Other bonds and obligations — 11,158 — 11,158 Marketable equity securities 62,284 3,257 — 65,541 Loans held for sale — 120,673 — 120,673 Derivative assets 622 16,157 4,838 21,617 Other assets — — 798 798 Derivative liabilities — 24,420 — 24,420
Schedule of loans held for sale	Aggregate Aggregate Aggregate Fair Value December 31, 2017 (In thousands) Loans Held for Sale $ 153,620 $ 149,022 $ 4,598 Aggregate Aggregate Aggregate Fair Value December 31, 2016 (In thousands) Loans Held for Sale $ 120,673 $ 118,178 $ 2,495
Schedule of changes in level 3 assets and liabilities that were measured at fair value on a recurring basis	The table below presents the changes in Level 3 assets that were measured at fair value on a recurring basis at year-end 2017 and 2016 : Assets (Liabilities) (In thousands) Trading Securities Available for Sale Commitments to Lend Forward Capitalized Servicing Rights Balance as of December 31, 2015 $ 14,189 $ 708 $ 323 $ 9 $ — Amounts acquired from First Choice Bank — — 3,900 — 696 Unrealized (loss) gain, net recognized in other non-interest income (362 ) — 13,563 91 102 Unrealized gain included in accumulated other comprehensive loss — — — — — Transfers to Level 2 — (708 ) — — — Paydown of trading security (598 ) — — — — Transfers to loans held for sale — — (13,048 ) — — Balance as of December 31, 2016 $ 13,229 $ — $ 4,738 $ 100 $ 798 Unrealized (loss) gain, net recognized in other non-interest income (320 ) — 63,894 (81 ) (221 ) Unrealized gain included in accumulated other comprehensive loss — — — — — Transfers to Level 2 — — — — — Paydown of trading security (632 ) — — — — Transfers to loans held for sale — — (63,373 ) — — Additions to servicing rights — — — — 3,257 Balance as of December 31, 2017 $ 12,277 $ — $ 5,259 $ 19 $ 3,834 Unrealized gains (losses) relating to instruments still held at December 31, 2017 $ 1,522 $ — $ 5,259 $ 19 $ (221 ) Unrealized gains relating to instruments still held at December 31, 2016 $ 1,843 $ — $ 4,738 $ 100 $ 102
Schedule of quantitative information about the significant unobservable inputs within Level 3	The following is a summary of applicable non-recurring fair value measurements. There are no liabilities measured on a non-recurring basis. December 31, 2017 Fair Value Measurements as of December 31, 2017 (In thousands) Level 3 Level 3 Inputs Assets Impaired loans $ 23,853 December 2017 Capitalized servicing rights 12,527 December 2017 Other real estate owned — — Total $ 36,380 December 31, 2016 Fair Value Measurements as of December 31, 2016 (In thousands) Level 3 Level 3 Assets Impaired loans $ 17,761 December 2016 Capitalized servicing rights 10,726 December 2016 Other real estate owned 151 Feb. 2016 - July 2016 Total $ 28,638
Summary of applicable non-recurring fair value measurements	The estimated fair values, and related carrying amounts, of the Company’s financial instruments follow. Certain financial instruments and all non-financial instruments are excluded from disclosure requirements. Accordingly, the aggregate fair value amounts presented herein may not necessarily represent the underlying fair value of the Company. December 31, 2017 Carrying Fair (In thousands) Level 1 Level 2 Level 3 Financial Assets Cash and cash equivalents $ 248,763 $ 248,763 $ 248,763 $ — $ — Trading security 12,277 12,277 — — 12,277 Securities available for sale 1,426,099 1,426,099 44,850 1,381,249 — Securities held to maturity 397,103 405,276 — 371,458 33,818 FHLB stock and restricted equity securities 63,085 N/A — N/A — Net loans 8,247,504 8,422,034 — — 8,422,034 Loans held for sale 153,620 153,620 — 153,620 — Accrued interest receivable 33,739 33,739 — 33,739 — Derivative assets 19,308 19,308 — 14,049 5,259 Assets held for sale 1,392 1,392 — 1,392 — Financial Liabilities Total deposits 8,749,530 8,731,527 — 8,731,527 — Short-term debt 667,300 667,246 — 667,246 — Long-term FHLB advances 380,436 378,766 — 378,766 — Subordinated notes 89,339 97,414 — 97,414 — Derivative liabilities 15,838 15,838 104 15,715 19 December 31, 2016 Carrying Fair (In thousands) Level 1 Level 2 Level 3 Financial Assets Cash and cash equivalents $ 113,075 $ 113,075 $ 113,075 $ — $ — Trading security 13,229 13,229 — — 13,229 Securities available for sale 1,209,537 1,209,537 62,284 1,147,253 — Securities held to maturity 334,368 337,680 — 300,806 36,874 FHLB stock and restricted equity securities 71,112 N/A — N/A — Net loans 6,505,789 6,532,745 — — 6,532,745 Loans held for sale 120,673 120,673 — 120,673 — Accrued interest receivable 26,113 26,113 — 26,113 — Derivative assets 21,617 21,617 622 16,157 4,838 Assets held for sale 322 322 — 322 — Financial Liabilities Total deposits 6,622,092 6,624,108 — 6,624,108 — Short-term debt 1,082,044 1,081,996 — 1,081,996 — Long-term FHLB advances 142,792 143,151 — 143,151 — Subordinated notes 89,161 96,973 — 96,973 — Derivative liabilities 24,420 24,420 — 24,420 —
Recurring
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Schedule of quantitative information about the significant unobservable inputs within Level 3	Quantitative information about the significant unobservable inputs within Level 3 recurring assets/(liabilities) as of December 31, 2017 and 2016 are as follows: Fair Value Significant Unobservable Input Value (In thousands) December 31, 2017 Valuation Techniques Unobservable Inputs Assets Trading Security $ 12,277 Discounted Cash Flow Discount Rate 2.74 % Forward Commitments 19 Historical Trend Closing Ratio 81.53 % Pricing Model Origination Costs, per loan $ 3,692 Commitments to Lend 5,259 Historical Trend Closing Ratio 81.53 % Pricing Model Origination Costs, per loan $ 3,692 Capitalized Servicing Rights 3,834 Discounted cash flow Constant prepayment rate (CPR) 10.00 % Discount rate 10.95 % Total $ 21,389 Fair Value Significant (In thousands) December 31, 2016 Valuation Techniques Unobservable Inputs Assets Trading Security $ 13,229 Discounted Cash Flow Discount Rate 2.62 % Forward Commitments 100 Historical Trend Closing Ratio 80.36 % Commitments to Lend 4,738 Pricing Model Origination Costs, per loan $ 3.692 Historical Trend Closing Ratio 80.36 % Capitalized Servicing Rights 798 Pricing Model Origination Costs, per loan $ 3.692 Discounted cash flow Constant prepayment rate (CPR) 10.40 % Discount rate 11.00 % Total $ 18,865
Non-recurring
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Schedule of quantitative information about the significant unobservable inputs within Level 3	Quantitative information about the significant unobservable inputs within Level 3 non-recurring assets as of December 31, 2017 and 2016 are as follows: (in thousands) December 31, 2017 Valuation Techniques Unobservable Inputs Range (Weighted Average) (a) Assets Impaired loans $ 23,853 Fair value of collateral Loss severity 38.72% to 0.21% (3.40%) Appraised value $10.9 to $5967 ($2,197) Capitalized servicing rights 12,527 Discounted cash flow Constant prepayment rate (CPR) 7.78% to 12.78% (10.38%) Discount rate 10.00% to 13.28% (11.72%) Other real estate owned — Fair value of collateral Appraised value — Total Assets $ 36,380 (a) Where dollar amounts are disclosed, the amounts represent the lowest and highest fair value of the respective assets in the population except for adjustments for market/property conditions, which represents the range of adjustments to individuals properties. (in thousands) December 31, 2016 Valuation Techniques Unobservable Inputs Range (Weighted Average) (a) Assets Impaired loans $ 17,761 Fair value of collateral Loss severity 0% to 88.70% (9.73%) Appraised value $0 to $2,192 ($1,026) Capitalized servicing rights 10,726 Discounted cash flow Constant prepayment rate (CPR) 7.35% to 14.28% (10.44%) Discount rate 10.00% to 14.00% (11.77%) Other real estate owned 151 Fair value of collateral Appraised value $101 to $129 ($122) Total Assets $ 28,638 (a) Where dollar amounts are disclosed, the amounts represent the lowest and highest fair value of the respective assets in the population except for adjustments for market/property conditions, which represents the range of adjustments to individuals properties.

CONDENSED FINANCIAL STATEMENT51

CONDENSED FINANCIAL STATEMENTS OF PARENT COMPANY (Tables)	12 Months Ended
	Dec. 31, 2017
Condensed Financial Information of Parent Company Only Disclosure [Abstract]
Schedule of Condensed Balance Sheets	CONDENSED BALANCE SHEETS December 31, (In thousands) 2017 2016 Assets Cash due from Berkshire Bank $ 83,380 $ 43,018 Investment in subsidiaries 1,470,859 1,127,706 Securities available for sale, at fair value 21,827 23,651 Other assets 12,138 1,372 Total assets $ 1,588,204 $ 1,195,747 Liabilities and Shareholders’ Equity Short term debt $ — $ 10,000 Subordinated notes 89,339 89,161 Accrued expenses 2,601 3,288 Shareholders’ equity 1,496,264 1,093,298 Total liabilities and shareholders’ equity $ 1,588,204 $ 1,195,747
Schedule of Condensed Statements of Income	CONDENSED STATEMENTS OF INCOME Years Ended December 31, (In thousands) 2017 2016 2015 Income: Dividends from subsidiaries $ 39,000 $ 33,000 $ 34,000 Other 5,864 4,072 2,763 Total income 44,864 37,072 36,763 Interest expense 5,338 5,743 5,674 Non-interest expenses 6,042 3,740 3,670 Total expense 11,380 9,483 9,344 Income before income taxes and equity in undistributed income of subsidiaries 33,484 27,589 27,419 Income tax benefit (1,783 ) (2,123 ) (2,518 ) Income before equity in undistributed income of subsidiaries 35,267 29,712 29,937 Equity in undistributed income of subsidiaries 19,980 28,958 19,581 Net income 55,247 58,670 49,518 Preferred stock dividend 219 — — Income available to common shareholders $ 55,028 $ 58,670 $ 49,518
Schedule of Condensed Statements of Cash Flows	CONDENSED STATEMENTS OF CASH FLOWS Years Ended December 31, (In thousands) 2017 2016 2015 Cash flows from operating activities: Net income $ 55,247 $ 58,670 $ 49,518 Adjustments to reconcile net income to net cash (used) provided by operating activities: Equity in undistributed income of subsidiaries (19,980 ) (28,958 ) (19,581 ) Other, net (7,964 ) 1,988 10,904 Net cash provided by operating activities 27,303 31,700 40,841 Cash flows from investing activities: Advances to subsidiaries (100,000 ) — — Acquisitions, net of cash paid — — (3,293 ) Purchase of securities (1,057 ) (18,016 ) (18 ) Sale of securities 2,101 — — Other, net 1,508 9,728 — Net cash (used) in investing activities (97,448 ) (8,288 ) (3,311 ) Cash flows from financing activities: Proceed from issuance of short term debt — 9,349 — Repayment of short term debt (9,822 ) — (9,935 ) Net proceeds from common stock 153,313 3,712 — Net proceeds from preferred stock — — — Net proceeds from reissuance of treasury stock — — 240 Payment to repurchase common stock — (4,632 ) (550 ) Common stock cash dividends paid (33,022 ) (24,916 ) (21,903 ) Preferred stock cash dividends paid (219 ) — — Other, net 257 11 167 Net cash provided provided/(used) by financing activities 110,507 (16,476 ) (31,981 ) Net change in cash and cash equivalents 40,362 6,936 5,549 Cash and cash equivalents at beginning of year 43,018 36,082 30,533 Cash and cash equivalents at end of year $ 83,380 $ 43,018 $ 36,082

QUARTERLY DATA (UNAUDITED) (Tab

QUARTERLY DATA (UNAUDITED) (Tables)	12 Months Ended
	Dec. 31, 2017
Quarterly Financial Information Disclosure [Abstract]
Schedule of Quarterly Results of Operations	Quarterly results of operations were as follows: 2017 2016 (In thousands, except per share data) Fourth Quarter Third Quarter Second Quarter First Quarter Fourth Quarter Third Quarter Second Quarter First Quarter Interest and dividend income $ 105,823 $ 89,060 $ 84,666 $ 80,709 $ 72,434 $ 70,511 $ 69,018 $ 68,476 Interest expense 19,457 17,062 15,121 13,823 13,276 12,540 11,577 10,779 Net interest income 86,366 71,998 69,545 66,886 59,158 57,971 57,441 57,697 Non-interest income 29,298 28,836 32,798 34,757 16,725 18,941 14,555 15,630 Total revenue 115,664 100,834 102,343 101,643 75,883 76,912 71,996 73,327 Provision for loan losses 6,141 4,900 4,889 5,095 4,100 4,734 4,522 4,006 Non-interest expense 90,041 65,820 69,523 74,326 61,090 48,844 46,268 47,100 Income before income taxes 19,482 30,114 27,931 22,222 10,693 23,334 21,206 22,221 Income tax expense (1) 22,292 7,211 8,237 6,762 362 6,953 5,249 6,220 Net (loss)/income $ (2,810 ) $ 22,903 $ 19,694 $ 15,460 $ 10,331 $ 16,381 $ 15,957 $ 16,001 Basic (loss)/earnings per common share $ (0.06 ) $ 0.57 $ 0.53 $ 0.44 $ 0.32 $ 0.53 $ 0.52 $ 0.52 Diluted (loss)/earnings per share $ (0.06 ) $ 0.57 $ 0.53 $ 0.44 $ 0.32 $ 0.53 $ 0.52 $ 0.52 Weighted average common shares outstanding: Basic 45,122 39,984 37,324 35,280 32,185 30,621 30,605 30,511 Diluted 45,122 40,145 37,474 35,452 32,381 30,811 30,765 30,688 (1) 2017 income tax expense includes $18.1 million charge to re-measure the net deferred tax asset at December 31, 2017 pursuant to the reduction in the corporate income tax rate from 35% to 21%, effective January 1, 2018, per the Tax Cuts and Jobs Act enacted on December 22, 2017.

NET INTEREST INCOME AFTER PRO53

NET INTEREST INCOME AFTER PROVISION FOR LOAN LOSSES (Tables)	12 Months Ended
	Dec. 31, 2017
Banking and Thrift, Interest [Abstract]
Schedule of Net Interest Income After Provision for Loan Losses	Presented below is net interest income after provision for loan losses for the three years ended 2017, 2016, and 2015, respectively: Years Ended December 31, (In thousands) 2017 2016 2015 Net interest income $ 294,795 $ 232,267 $ 213,849 Provision for loan losses 21,025 17,362 16,726 Net interest income after provision for loan losses 273,770 214,905 197,123 Total non-interest income 125,689 65,851 54,288 Total non-interest expense 299,710 203,302 196,829 Income from continuing operations before income taxes 99,749 77,454 54,582 Income tax expense 44,502 18,784 5,064 Net income $ 55,247 $ 58,670 $ 49,518

SUMMARY OF SIGNIFICANT ACCOUN54

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details)	12 Months Ended
	Dec. 31, 2017segment
Accounting Policies [Abstract]
Number of days until which automobile loans accrue, after which they are charged off	120 days
Minimum number of days past due for loans excluding automobile loans on which interest is generally not accrued	90 days
Threshold percentage of amortization of net actuarial gain or loss in net periodic benefit cost over the average remaining service period of active participants in the Plans	10.00%
Number of reportable segments (segment)	1
Number of operating segments (segment)	1

ACQUISITIONS - COMMERCE NARATIV

ACQUISITIONS - COMMERCE NARATIVE (Details) $ / shares in Units, $ in Millions	Oct. 13, 2017USD ($)banking_office$ / sharesshares	Dec. 31, 2017shares	Dec. 31, 2016shares
Business Acquisition [Line Items]
Common stock, shares outstanding (shares)		45,290,433	35,672,817
Commerce Bank
Business Acquisition [Line Items]
Number of branch banking offices | banking_office	16
Common stock, shares outstanding (shares)	6,328,000
Commerce Bank | Common Stock for Common Stock
Business Acquisition [Line Items]
Equity interest, share exchange ratio	0.93
Commerce Bank | Common Stock for Series B Preferred Stock
Business Acquisition [Line Items]
Equity interest, share exchange ratio	0.465
Commerce Bank | Preferred Stock for Common Stock
Business Acquisition [Line Items]
Equity interest, share exchange ratio	2
Commerce Bank | Common Stock
Business Acquisition [Line Items]
Business acquisition, equity interest issued (shares)	4,842,000
Equity issued, value | $	$ 188.6
Share price (USD per share) | $ / shares	$ 38.95
Commerce Bank | Preferred Stock
Business Acquisition [Line Items]
Business acquisition, equity interest issued (shares)	522,000
Equity issued, value | $	$ 40.6
Commerce Bancshares 2010 Long-Term Incentive Plan
Business Acquisition [Line Items]
Share price pursuant to merger (USD per share) | $ / shares	$ 34

ACQUISITIONS - COMMERCE BANK AC

ACQUISITIONS - COMMERCE BANK ACQUIRED AND LIABILITIES ASSUMED (Details) - USD ($) $ in Thousands	Oct. 13, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Recognized amounts of identifiable assets acquired and (liabilities) assumed, at fair value:
Goodwill	$ 116,181	$ 519,287	$ 403,106	$ 323,943
Loans		8,299,338	6,549,787
Accretable yield		$ 11,561	$ 8,738	$ 6,925	$ 2,541
Commerce Bank
Consideration paid:
Cash in lieu paid to Commerce shareholders	1
Total consideration paid	229,233
Recognized amounts of identifiable assets acquired and (liabilities) assumed, at fair value:
Cash and short-term investments	374,611
Investment securities	113,847
Loans, net	1,240,751
Premises and equipment	14,277
Core deposit intangibles	22,400
Deferred tax assets, net	34,536
Goodwill and other intangibles	0
Other assets	49,045
Deposits	(1,712,052)
Borrowings	(19,542)
Other liabilities	(4,821)
Total identifiable net assets	113,052
Allowance for loan and lease losses	15,000
Accretable yield	$ 10,815
Estimated useful life of deposits	10 years
Write-down of repossessed assets	$ 3,500
Commerce Bank | Performing
Recognized amounts of identifiable assets acquired and (liabilities) assumed, at fair value:
Loans	1,180,000
Loans acquired	1,170,000
Commerce Bank | Impaired loan
Recognized amounts of identifiable assets acquired and (liabilities) assumed, at fair value:
Loans	163,100
Loans acquired	71,100
Accretable yield	10,800
Fair value adjustment, amortized into income	4,000
As Acquired | Commerce Bank
Recognized amounts of identifiable assets acquired and (liabilities) assumed, at fair value:
Cash and short-term investments	374,611
Investment securities	115,274
Loans, net	1,327,256
Premises and equipment	8,931
Core deposit intangibles	0
Deferred tax assets, net	7,956
Goodwill and other intangibles	11,233
Other assets	52,709
Deposits	(1,710,872)
Borrowings	(19,542)
Other liabilities	(5,086)
Total identifiable net assets	162,470
Fair Value Adjustment | Commerce Bank
Recognized amounts of identifiable assets acquired and (liabilities) assumed, at fair value:
Cash and short-term investments	0
Investment securities	(1,427)
Loans, net	(86,505)
Premises and equipment	5,346
Core deposit intangibles	22,400
Deferred tax assets, net	26,580
Goodwill and other intangibles	(11,233)
Other assets	(3,664)
Deposits	(1,180)
Borrowings	0
Other liabilities	265
Total identifiable net assets	(49,418)
Common stock | Commerce Bank
Consideration paid:
Company common stock issued	188,599
Preferred Stock | Commerce Bank
Consideration paid:
Company common stock issued	40,633
Buildings | Commerce Bank
Recognized amounts of identifiable assets acquired and (liabilities) assumed, at fair value:
Premises and equipment	5,700
Land | Commerce Bank
Recognized amounts of identifiable assets acquired and (liabilities) assumed, at fair value:
Premises and equipment	700
Furniture, fixtures and equipment | Commerce Bank
Recognized amounts of identifiable assets acquired and (liabilities) assumed, at fair value:
Reduction in book value	$ 1,000

ACQUISITIONS - COMMERCE BANK LO

ACQUISITIONS - COMMERCE BANK LOAN PORTOFOLIO ACQUIRED (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Oct. 13, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Business Acquisition [Line Items]
Interest component of expected cash flows (accretable discount)	$ (11,561)		$ (8,738)	$ (6,925)	$ (2,541)
Commerce Bank
Business Acquisition [Line Items]
Gross contractual receivable amounts at acquisition		$ 163,125
Contractual cash flows not expected to be collected (nonaccretable discount)		(81,205)
Expected cash flows at acquisition		81,920
Interest component of expected cash flows (accretable discount)		(10,815)
Fair value of acquired loans		$ 71,105

ACQUISITIONS - PRO FORMA NARRAT

ACQUISITIONS - PRO FORMA NARRATIVE (Details) - USD ($) shares in Thousands	Oct. 13, 2017	Dec. 31, 2017	Dec. 31, 2016
Business Acquisition [Line Items]
Business acquisition, pro forma estimated tax rate (percent)		40.00%
Commerce Bank
Business Acquisition [Line Items]
Acquisition related costs		$ 17,800,000	$ 0
Common stock | Commerce Bank
Business Acquisition [Line Items]
Business acquisition, equity interest issued (shares)	4,842
Preferred Stock | Commerce Bank
Business Acquisition [Line Items]
Business acquisition, equity interest issued (shares)	522

ACQUISITIONS - PRO FORMA INFORM

ACQUISITIONS - PRO FORMA INFORMATION (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Business Combinations [Abstract]
Net interest income	$ 344,797	$ 302,012
Non-interest income	134,818	77,192
Income available to common shareholders	$ 77,340	$ 78,859

CASH AND CASH EQUIVALENTS (Deta

CASH AND CASH EQUIVALENTS (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
CASH AND CASH EQUIVALENTS
Short-term investments	$ 248,763	$ 113,075
Reserve requirement, included in cash and equivalents	20,400	17,000
Short-term investments pledged as collateral
CASH AND CASH EQUIVALENTS
Short-term investments	$ 2,100	$ 900

TRADING SECURITY (Details)

TRADING SECURITY (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Trading Securities [Abstract]
Amortized cost	$ 10,800	$ 11,400
Fair value	12,277	13,229
Unrealized gains (losses)	$ (300)	$ (400)	$ (200)

SECURITIES (Details)

SECURITIES (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Available-for-sale Debt Securities, Amortized Cost Basis [Abstract]
Available-for-sale debt securities, amortized cost basis	$ 1,387,250	$ 1,145,448
Available-for-sale debt securities, accumulated gross unrealized gain, before tax	7,108	7,234
Available-for-sale debt securities, accumulated gross unrealized loss, before tax	(13,444)	(8,686)
Available-for-sale securities, debt securities	1,380,914	1,143,996
Available-for-sale Equity Securities, Amortized Cost Basis [Abstract]
Available-for-sale equity securities, amortized cost basis	36,483	47,858
Available-for-sale equity securities, accumulated gross unrealized gain, before tax	9,211	19,296
Available-for-sale equity securities, accumulated gross unrealized loss, before tax	(509)	(1,613)
Available-for-sale securities, equity securities	45,185	65,541
Available-for-sale Securities, Fair Value to Amortized Cost Basis [Abstract]
Available-for-sale securities, amortized cost basis	1,423,733	1,193,306
Available-for-sale securities, accumulated gross unrealized gain, before tax	16,319	26,530
Available-for-sale securities, accumulated gross unrealized loss, before tax	(13,953)	(10,299)
Available-for-securities	1,426,099	1,209,537
Held-to-maturity Securities, Unclassified [Abstract]
Held-to-maturity securities	397,103	334,368
Held-to-maturity securities, accumulated unrecognized holding gain	10,316	6,816
Held-to-maturity securities, accumulated unrecognized holding loss	(2,143)	(3,504)
Held-to-maturity securities, fair value	405,276	337,680
Available-for-sale Securities and Held-to-maturity Securities [Abstract]
Held to maturity and available for sale securities amortized cost	1,820,836	1,527,674
Held to maturity and available for sale securities, gross unrealized gain	26,635	33,346
Held to maturity and available for sale securities, gross unrealized losses	(16,096)	(13,803)
Available for sale securities and held to maturity securities	1,831,375	1,547,217
Municipal bonds and obligations
Held-to-maturity Securities, Unclassified [Abstract]
Held-to-maturity securities	270,310	203,463
Held-to-maturity securities, accumulated unrecognized holding gain	8,675	3,939
Held-to-maturity securities, accumulated unrecognized holding loss	(90)	(2,416)
Held-to-maturity securities, fair value	278,895	204,986
Agency collateralized mortgage obligations
Held-to-maturity Securities, Unclassified [Abstract]
Held-to-maturity securities	73,742	75,655
Held-to-maturity securities, accumulated unrecognized holding gain	1,045	1,281
Held-to-maturity securities, accumulated unrecognized holding loss	(486)	(411)
Held-to-maturity securities, fair value	74,301	76,525
Tax advantaged economic development bonds
Held-to-maturity Securities, Unclassified [Abstract]
Held-to-maturity securities	34,357	35,278
Held-to-maturity securities, accumulated unrecognized holding gain	596	1,596
Held-to-maturity securities, accumulated unrecognized holding loss	(1,135)	0
Held-to-maturity securities, fair value	33,818	36,874
Other bonds and obligations
Held-to-maturity Securities, Unclassified [Abstract]
Held-to-maturity securities	321	325
Held-to-maturity securities, accumulated unrecognized holding gain	0	0
Held-to-maturity securities, accumulated unrecognized holding loss	0	0
Held-to-maturity securities, fair value	321	325
Municipal bonds and obligations
Available-for-sale Debt Securities, Amortized Cost Basis [Abstract]
Available-for-sale debt securities, amortized cost basis	113,427	117,910
Available-for-sale debt securities, accumulated gross unrealized gain, before tax	5,012	2,955
Available-for-sale debt securities, accumulated gross unrealized loss, before tax	(206)	(1,049)
Available-for-sale securities, debt securities	118,233	119,816
Agency collateralized mortgage obligations
Available-for-sale Debt Securities, Amortized Cost Basis [Abstract]
Available-for-sale debt securities, amortized cost basis	859,705	652,680
Available-for-sale debt securities, accumulated gross unrealized gain, before tax	397	2,522
Available-for-sale debt securities, accumulated gross unrealized loss, before tax	(8,944)	(3,291)
Available-for-sale securities, debt securities	851,158	651,911
Agency mortgage-backed securities
Available-for-sale Debt Securities, Amortized Cost Basis [Abstract]
Available-for-sale debt securities, amortized cost basis	218,926	230,308
Available-for-sale debt securities, accumulated gross unrealized gain, before tax	279	557
Available-for-sale debt securities, accumulated gross unrealized loss, before tax	(2,265)	(2,181)
Available-for-sale securities, debt securities	216,940	228,684
Held-to-maturity Securities, Unclassified [Abstract]
Held-to-maturity securities	7,892	9,102
Held-to-maturity securities, accumulated unrecognized holding gain	0	0
Held-to-maturity securities, accumulated unrecognized holding loss	(164)	(243)
Held-to-maturity securities, fair value	7,728	8,859
Agency commercial mortgage-backed securities
Available-for-sale Debt Securities, Amortized Cost Basis [Abstract]
Available-for-sale debt securities, amortized cost basis	64,025	65,673
Available-for-sale debt securities, accumulated gross unrealized gain, before tax	41	229
Available-for-sale debt securities, accumulated gross unrealized loss, before tax	(1,761)	(1,368)
Available-for-sale securities, debt securities	62,305	64,534
Held-to-maturity Securities, Unclassified [Abstract]
Held-to-maturity securities	10,481	10,545
Held-to-maturity securities, accumulated unrecognized holding gain	0	0
Held-to-maturity securities, accumulated unrecognized holding loss	(268)	(434)
Held-to-maturity securities, fair value	10,213	10,111
Corporate bonds
Available-for-sale Debt Securities, Amortized Cost Basis [Abstract]
Available-for-sale debt securities, amortized cost basis	110,076	56,320
Available-for-sale debt securities, accumulated gross unrealized gain, before tax	882	408
Available-for-sale debt securities, accumulated gross unrealized loss, before tax	(237)	(722)
Available-for-sale securities, debt securities	110,721	56,006
Trust preferred securities
Available-for-sale Debt Securities, Amortized Cost Basis [Abstract]
Available-for-sale debt securities, amortized cost basis	11,334	11,578
Available-for-sale debt securities, accumulated gross unrealized gain, before tax	343	368
Available-for-sale debt securities, accumulated gross unrealized loss, before tax	0	(59)
Available-for-sale securities, debt securities	11,677	11,887
Other bonds and obligations
Available-for-sale Debt Securities, Amortized Cost Basis [Abstract]
Available-for-sale debt securities, amortized cost basis	9,757	10,979
Available-for-sale debt securities, accumulated gross unrealized gain, before tax	154	195
Available-for-sale debt securities, accumulated gross unrealized loss, before tax	(31)	(16)
Available-for-sale securities, debt securities	$ 9,880	$ 11,158

SECURITIES - Narrative (Details

SECURITIES - Narrative (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2017USD ($)security	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)
Investment Holdings [Line Items]
Held-to-maturity securities, unrecognized holding gain | $	$ 7,700	$ 9,000
Proceeds from sales of securities available for sale | $	188,921	421,843	$ 41,169
Available-for-sale securities, accumulated gross unrealized loss before tax | $	13,953	10,299
Securities available for sale, at fair value | $	1,426,099	1,209,537
Level 2
Investment Holdings [Line Items]
Securities available for sale, at fair value | $	$ 1,381,249	1,147,253
Municipal bonds and obligations
Investment Holdings [Line Items]
Aggregate unrealized losses as a percentage of the amortized cost of the securities in unrealized loss positions	0.70%
Number of HTM investment securities in unrealized loss positions (security)	12
Number of securities in the portfolio of HTM (security)	231
Collateralized mortgage obligations
Investment Holdings [Line Items]
Aggregate unrealized losses as a percentage of the amortized cost of the securities in unrealized loss positions	3.60%
Number of HTM investment securities in unrealized loss positions (security)	1
Number of securities in the portfolio of HTM (security)	9
Mortgage-backed Securities
Investment Holdings [Line Items]
Aggregate unrealized losses as a percentage of the amortized cost of the securities in unrealized loss positions	2.40%
Number of HTM investment securities in unrealized loss positions (security)	2
Number of securities in the portfolio of HTM (security)	2
Debt securities | Municipal bonds and obligations
Investment Holdings [Line Items]
Available-for-sale securities in an unrealized loss position (security)	6
Available for sale securities portfolio, number of securities (security)	260
Aggregate unrealized losses as a percentage of the amortized cost of the securities in unrealized loss positions	2.30%
Debt securities | Collateralized mortgage obligations
Investment Holdings [Line Items]
Available-for-sale securities in an unrealized loss position (security)	179
Available for sale securities portfolio, number of securities (security)	234
Aggregate unrealized losses as a percentage of the amortized cost of the securities in unrealized loss positions	1.20%
Debt securities | Mortgage-backed Securities
Investment Holdings [Line Items]
Available-for-sale securities in an unrealized loss position (security)	58
Available for sale securities portfolio, number of securities (security)	103
Aggregate unrealized losses as a percentage of the amortized cost of the securities in unrealized loss positions	1.80%
Debt securities | Corporate bonds
Investment Holdings [Line Items]
Available-for-sale securities in an unrealized loss position (security)	1
Available for sale securities portfolio, number of securities (security)	20
Aggregate unrealized losses as a percentage of the amortized cost of the securities in unrealized loss positions	1.50%
Debt securities | Other bonds and obligations
Investment Holdings [Line Items]
Available-for-sale securities in an unrealized loss position (security)	6
Available for sale securities portfolio, number of securities (security)	9
Aggregate unrealized losses as a percentage of the amortized cost of the securities in unrealized loss positions	1.00%
Debt securities | Tax advantaged economic development bonds
Investment Holdings [Line Items]
Aggregate unrealized losses as a percentage of the amortized cost of the securities in unrealized loss positions	13.40%
Number of HTM investment securities in unrealized loss positions (security)	1
Number of securities in the portfolio of HTM (security)	7
Marketable equity securities
Investment Holdings [Line Items]
Available-for-sale securities in an unrealized loss position (security)	2
Available for sale securities portfolio, number of securities (security)	20
Aggregate unrealized losses as a percentage of the amortized cost of the securities in unrealized loss positions	11.30%
Net unrealized holding gain on AFS securities
Investment Holdings [Line Items]
Other accumulated comprehensive income/(loss), before tax | $	$ 10,034	25,176
Income tax benefit related to items of accumulated other comprehensive income/(loss) | $	4,026	9,636
Net unrealized holding gain on AFS securities | Securities Available for Sale
Investment Holdings [Line Items]
Other accumulated comprehensive income/(loss), before tax | $	$ 2,300	$ 16,200

SECURITIES - Amortized Cost and

SECURITIES - Amortized Cost and Estimated Fair Value by Contractual Maturity (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Available for sale, Amortized Cost
Within 1 year	$ 622
Over 1 year to 5 years	32,659
Over 5 years to 10 years	75,261
Over 10 years	136,052
Total bonds and obligations	244,594
Marketable equity securities	36,483	$ 47,858
Mortgage-backed securities	1,142,656
Available-for-sale securities, amortized cost basis	1,423,733	1,193,306
Available for sale, Fair Value
Within 1 year	623
Over 1 year to 5 years	32,972
Over 5 years to 10 years	76,745
Over 10 years	140,171
Total bonds and obligations	250,511
Marketable equity securities	45,185	65,541
Mortgage-backed securities	1,130,403
Available-for-securities	1,426,099	1,209,537
Held to maturity, Amortized Cost
Within 1 year	1,261
Over 1 year to 5 years	25,892
Over 5 years to 10 years	8,752
Over 10 years	269,083
Total bonds and obligations	304,988
Mortgage-backed securities	92,115
Held-to-maturity securities	397,103	334,368
Held to maturity, Fair Value
Within 1 year	1,261
Over 1 year to 5 years	26,422
Over 5 years to 10 years	8,917
Over 10 years	276,434
Total bonds and obligations	313,034
Mortgage-backed securities	92,242
Held-to-maturity securities	$ 405,276	$ 337,680

SECURITIES - Pledged Securities

SECURITIES - Pledged Securities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Amortized Cost
Securities pledged to swap counterparties	$ 24,410	$ 51,292
Securities pledged for municipal deposits	210,382	147,950
Securities pledged, amortized cost	234,792	199,242
Fair Value
Securities pledged to swap counterparties	24,240	51,290
Securities pledged for municipal deposits	214,513	148,435
Securities pledged, fair value	238,753	199,725
Components of net realized gains and losses on the sale of AFS securities
Gross realized gains	13,877	2,762	$ 4,567
Gross realized losses	(1,279)	(3,313)	(2,457)
Net realized gains/(losses)	$ 12,598	$ (551)	$ 2,110

SECURITIES - Reclassifications

SECURITIES - Reclassifications out of AOCI into Earnings (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Securities available for sale
Less Than Twelve Months, Gross Unrealized Losses	$ 8,469	$ 8,044
Less Than Twelve Months, Fair Value	773,813	523,307
Over Twelve Months, Gross Unrealized Losses	5,484	2,255
Over Twelve Months, Fair Value	211,750	28,874
Total Gross Unrealized Losses	13,953	10,299
Total Fair Value	985,563	552,181
Securities held to maturity
Less Than Twelve Months, Gross Unrealized Losses	1,170	3,504
Less Than Twelve Months, Fair Value	17,518	103,002
Over Twelve Months, Gross Unrealized Losses	973	0
Over Twelve Months, Fair Value	32,946	0
Total Gross Unrealized Losses	2,143	3,504
Total Fair Value	50,464	103,002
Securities available for sale and held to maturity
Less Than Twelve Months, Gross Unrealized Losses	9,639	11,548
Less Than Twelve Months, Fair Value	791,331	626,309
Over Twelve Months, Gross Unrealized Losses	6,457	2,255
Over Twelve Months, Fair Value	244,696	28,874
Total Gross Unrealized Losses	16,096	13,803
Total Fair Value	1,036,027	655,183
Debt securities
Securities available for sale
Less Than Twelve Months, Gross Unrealized Losses	7,960	7,887
Less Than Twelve Months, Fair Value	770,082	516,707
Over Twelve Months, Gross Unrealized Losses	5,484	799
Over Twelve Months, Fair Value	211,750	22,947
Total Gross Unrealized Losses	13,444	8,686
Total Fair Value	981,832	539,654
Debt securities | Municipal bonds and obligations
Securities available for sale
Less Than Twelve Months, Gross Unrealized Losses	0	1,049
Less Than Twelve Months, Fair Value	0	13,839
Over Twelve Months, Gross Unrealized Losses	206	0
Over Twelve Months, Fair Value	8,985	0
Total Gross Unrealized Losses	206	1,049
Total Fair Value	8,985	13,839
Securities held to maturity
Less Than Twelve Months, Gross Unrealized Losses	35	2,416
Less Than Twelve Months, Fair Value	10,213	69,308
Over Twelve Months, Gross Unrealized Losses	55	0
Over Twelve Months, Fair Value	2,059	0
Total Gross Unrealized Losses	90	2,416
Total Fair Value	12,272	69,308
Debt securities | Agency collateralized mortgage obligations
Securities available for sale
Less Than Twelve Months, Gross Unrealized Losses	6,849	3,291
Less Than Twelve Months, Fair Value	655,479	319,448
Over Twelve Months, Gross Unrealized Losses	2,095	0
Over Twelve Months, Fair Value	80,401	0
Total Gross Unrealized Losses	8,944	3,291
Total Fair Value	735,880	319,448
Securities held to maturity
Less Than Twelve Months, Gross Unrealized Losses	0	411
Less Than Twelve Months, Fair Value	0	14,724
Over Twelve Months, Gross Unrealized Losses	486	0
Over Twelve Months, Fair Value	12,946	0
Total Gross Unrealized Losses	486	411
Total Fair Value	12,946	14,724
Debt securities | Agency residential mortgage-backed securities
Securities available for sale
Less Than Twelve Months, Gross Unrealized Losses	765	2,153
Less Than Twelve Months, Fair Value	95,800	130,766
Over Twelve Months, Gross Unrealized Losses	1,500	28
Over Twelve Months, Fair Value	65,323	2,061
Total Gross Unrealized Losses	2,265	2,181
Total Fair Value	161,123	132,827
Securities held to maturity
Less Than Twelve Months, Gross Unrealized Losses	0	243
Less Than Twelve Months, Fair Value	0	8,859
Over Twelve Months, Gross Unrealized Losses	164	0
Over Twelve Months, Fair Value	7,728	0
Total Gross Unrealized Losses	164	243
Total Fair Value	7,728	8,859
Debt securities | Agency commercial mortgage-backed securities
Securities available for sale
Less Than Twelve Months, Gross Unrealized Losses	334	1,368
Less Than Twelve Months, Fair Value	17,379	44,860
Over Twelve Months, Gross Unrealized Losses	1,427	0
Over Twelve Months, Fair Value	39,268	0
Total Gross Unrealized Losses	1,761	1,368
Total Fair Value	56,647	44,860
Securities held to maturity
Less Than Twelve Months, Gross Unrealized Losses	0	434
Less Than Twelve Months, Fair Value	0	10,111
Over Twelve Months, Gross Unrealized Losses	268	0
Over Twelve Months, Fair Value	10,213	0
Total Gross Unrealized Losses	268	434
Total Fair Value	10,213	10,111
Debt securities | Tax advantaged economic development bonds
Securities held to maturity
Less Than Twelve Months, Gross Unrealized Losses	1,135
Less Than Twelve Months, Fair Value	7,305
Over Twelve Months, Gross Unrealized Losses	0
Over Twelve Months, Fair Value	0
Total Gross Unrealized Losses	1,135
Total Fair Value	7,305
Debt securities | Corporate bonds
Securities available for sale
Less Than Twelve Months, Gross Unrealized Losses	1	11
Less Than Twelve Months, Fair Value	328	4,780
Over Twelve Months, Gross Unrealized Losses	236	711
Over Twelve Months, Fair Value	15,769	19,655
Total Gross Unrealized Losses	237	722
Total Fair Value	16,097	24,435
Debt securities | Trust preferred securities
Securities available for sale
Less Than Twelve Months, Gross Unrealized Losses	0	0
Less Than Twelve Months, Fair Value	0	0
Over Twelve Months, Gross Unrealized Losses	0	59
Over Twelve Months, Fair Value	0	1,204
Total Gross Unrealized Losses	0	59
Total Fair Value	0	1,204
Debt securities | Other bonds and obligations
Securities available for sale
Less Than Twelve Months, Gross Unrealized Losses	11	15
Less Than Twelve Months, Fair Value	1,096	3,014
Over Twelve Months, Gross Unrealized Losses	20	1
Over Twelve Months, Fair Value	2,004	27
Total Gross Unrealized Losses	31	16
Total Fair Value	3,100	3,041
Marketable equity securities
Securities available for sale
Less Than Twelve Months, Gross Unrealized Losses	509	157
Less Than Twelve Months, Fair Value	3,731	6,600
Over Twelve Months, Gross Unrealized Losses	0	1,456
Over Twelve Months, Fair Value	0	5,927
Total Gross Unrealized Losses	509	1,613
Total Fair Value	$ 3,731	$ 12,527

LOANS (Details)

LOANS (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	$ 8,299,338	$ 6,549,787
Commercial loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	5,068,681	3,678,476
Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	3,264,742	2,616,438
Commercial real estate | Construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	266,336	287,509
Commercial real estate | Single and multi-family
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	423,165	317,491
Commercial real estate | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	2,575,241	2,011,438
Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	1,803,939	1,062,038
Residential
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	2,102,807	1,893,131
Residential | Construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	5,410	11,982
Residential | 1-4 family
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	2,097,397	1,881,149
Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	1,127,850	978,180
Consumer | Home equity
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	410,181	393,800
Consumer | Auto and other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	717,669	584,380
Business Activities Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	6,112,198	5,221,307
Business Activities Loans | Commercial loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	3,400,276	2,834,446
Business Activities Loans | Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	2,217,707	1,926,344
Business Activities Loans | Commercial real estate | Construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	181,371	253,302
Business Activities Loans | Commercial real estate | Single and multi-family
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	217,083	191,819
Business Activities Loans | Commercial real estate | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	1,819,253	1,481,223
Business Activities Loans | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	1,182,569	908,102
Business Activities Loans | Residential
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	1,813,201	1,594,972
Business Activities Loans | Residential | Construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	5,177	11,178
Business Activities Loans | Residential | 1-4 family
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	1,808,024	1,583,794
Business Activities Loans | Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	898,721	791,889
Business Activities Loans | Consumer | Home equity
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	294,954	313,521
Business Activities Loans | Consumer | Auto and other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	603,767	478,368
Acquired Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	2,187,140	1,328,480
Acquired Loans | Commercial loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	1,668,405	844,030
Acquired Loans | Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	1,047,035	690,094
Acquired Loans | Commercial real estate | Construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	84,965	34,207
Acquired Loans | Commercial real estate | Single and multi-family
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	206,082	125,672
Acquired Loans | Commercial real estate | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	755,988	530,215
Acquired Loans | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	621,370	153,936
Acquired Loans | Residential
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	289,606	298,159
Acquired Loans | Residential | Construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	233	804
Acquired Loans | Residential | 1-4 family
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	289,373	297,355
Acquired Loans | Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	229,129	186,291
Acquired Loans | Consumer | Home equity
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	115,227	80,279
Acquired Loans | Consumer | Auto and other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	$ 113,902	$ 106,012

LOANS - Unamortized Net Costs a

LOANS - Unamortized Net Costs and Premiums (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Receivables [Abstract]
Unamortized net loan origination costs	$ 24,669	$ 21,972
Unamortized net premium on purchased loans	4,311	4,849
Total unamortized net costs and premiums	$ 28,980	$ 26,821

LOANS - Narrative (Details)

LOANS - Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Accounts, Notes, Loans and Financing Receivable [Line Items]
Participating serving loans	$ 1,800,000,000	$ 500,000,000
Payments to acquire loans and leases held-for-investment	500,900,000	190,800,000
Proceeds from sale of loans and leases held-for-investment	514,500,000	307,700,000
Gain (loss) on sales of loans, net	11,700,000	8,000,000	$ 6,000,000
Loans	8,299,338,000	6,549,787,000
Loans pledged as collateral	350,700,000
Due to related parties	50,800,000	38,700,000
Loans receivable, related parties	44,100,000	25,600,000
Non-accrual loans	22,816,000	22,157,000
Additional funds committed amount	$ 0
Borrower's sustained repayment performance period	6 months
Acquired Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	$ 2,187,140,000	1,328,480,000
Acquired credit impaired loans	97,300,000	46,800,000
Non-accrual loans	7,157,000	5,341,000
Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	3,264,742,000	2,616,438,000
Non-accrual loans	7,267,000	5,883,000
Commercial real estate | Acquired Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	1,047,035,000	690,094,000
Acquired credit impaired loans	53,300,000	34,800,000
Non-accrual loans	2,250,000	1,202,000
Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	1,803,939,000	1,062,038,000
Non-accrual loans	7,228,000	7,440,000
Commercial and industrial | Acquired Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	621,370,000	153,936,000
Acquired credit impaired loans	34,600,000	3,400,000
Non-accrual loans	1,333,000	1,155,000
Residential
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	2,102,807,000	1,893,131,000
Non-accrual loans	2,883,000	3,795,000
Repossessed assets		151,000
Residential | Mortgages
Accounts, Notes, Loans and Financing Receivable [Line Items]
Collateral for residential mortgage loans	4,900,000	4,800,000
Residential | Acquired Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	289,606,000	298,159,000
Acquired credit impaired loans	7,000,000	7,300,000
Non-accrual loans	1,217,000	1,572,000
Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	1,127,850,000	978,180,000
Non-accrual loans	5,438,000	5,039,000
Consumer | Acquired Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	229,129,000	186,291,000
Acquired credit impaired loans	2,400,000	1,300,000
Non-accrual loans	2,357,000	1,412,000
Total Loans | 6512 Operators of Nonresidential Buildings | Credit Concentration Risk
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	$ 1,300,000,000	$ 1,100,000,000
Concentration risk, percentage	15.80%	16.80%

LOANS - Accretable Yield (Detai

LOANS - Accretable Yield (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield Movement Schedule [Roll Forward]
Balance at beginning of period	$ 8,738	$ 6,925	$ 2,541
Acquisitions	10,815	6,125	4,777
Reclassification from nonaccretable difference for loans with improved cash flows	(23)	2,488	3,640
Changes in expected cash flows that do not affect nonaccretable difference	(2,380)	(3,018)	0
Reclassification to TDR	0	(185)	0
Accretion	(5,589)	(3,597)	(4,033)
Balance at end of period	$ 11,561	$ 8,738	$ 6,925

LOANS - Summary of Past Due Loa

LOANS - Summary of Past Due Loans for Business Activities Loans (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	$ 8,299,338	$ 6,549,787
Commercial real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	3,264,742	2,616,438
Commercial real estate | Construction
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	266,336	287,509
Commercial real estate | Single and multi-family
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	423,165	317,491
Commercial real estate | Other
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	2,575,241	2,011,438
Commercial and industrial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	1,803,939	1,062,038
Residential
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	2,102,807	1,893,131
Residential | Construction
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	5,410	11,982
Residential | 1-4 family
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	2,097,397	1,881,149
Consumer
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	1,127,850	978,180
Consumer | Home equity
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	410,181	393,800
Consumer | Auto and other
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	717,669	584,380
Business Activities Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	33,264	32,277
Current	6,078,934	5,189,030
Total loans	6,112,198	5,221,307
Past Due greater than 90 days and Accruing	1,368	2,438
Business Activities Loans | 30-59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	12,201	8,174
Business Activities Loans | 60-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	4,036	4,849
Business Activities Loans | 90 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	17,027	19,254
Business Activities Loans | Commercial real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	7,447	8,288
Current	2,210,260	1,918,056
Total loans	2,217,707	1,926,344
Past Due greater than 90 days and Accruing	457	155
Business Activities Loans | Commercial real estate | Construction
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0	0
Current	181,371	253,302
Total loans	181,371	253,302
Past Due greater than 90 days and Accruing	0	0
Business Activities Loans | Commercial real estate | Single and multi-family
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	451	1,352
Current	216,632	190,467
Total loans	217,083	191,819
Past Due greater than 90 days and Accruing	0	155
Business Activities Loans | Commercial real estate | Other
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	6,996	6,936
Current	1,812,257	1,474,287
Total loans	1,819,253	1,481,223
Past Due greater than 90 days and Accruing	457	0
Business Activities Loans | Commercial real estate | 30-59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	1,925	1,099
Business Activities Loans | Commercial real estate | 30-59 Days Past Due | Construction
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0	0
Business Activities Loans | Commercial real estate | 30-59 Days Past Due | Single and multi-family
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0	618
Business Activities Loans | Commercial real estate | 30-59 Days Past Due | Other
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	1,925	481
Business Activities Loans | Commercial real estate | 60-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	48	2,353
Business Activities Loans | Commercial real estate | 60-89 Days Past Due | Construction
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0	0
Business Activities Loans | Commercial real estate | 60-89 Days Past Due | Single and multi-family
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0	110
Business Activities Loans | Commercial real estate | 60-89 Days Past Due | Other
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	48	2,243
Business Activities Loans | Commercial real estate | 90 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	5,474	4,836
Business Activities Loans | Commercial real estate | 90 Days Past Due | Construction
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0	0
Business Activities Loans | Commercial real estate | 90 Days Past Due | Single and multi-family
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	451	624
Business Activities Loans | Commercial real estate | 90 Days Past Due | Other
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	5,023	4,212
Business Activities Loans | Commercial and industrial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	11,966	10,681
Current	1,170,603	897,421
Total loans	1,182,569	908,102
Past Due greater than 90 days and Accruing	128	5
Business Activities Loans | Commercial and industrial | 30-59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	4,031	3,090
Business Activities Loans | Commercial and industrial | 60-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	1,912	1,301
Business Activities Loans | Commercial and industrial | 90 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	6,023	6,290
Business Activities Loans | Residential
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	4,840	6,283
Current	1,808,361	1,588,689
Total loans	1,813,201	1,594,972
Past Due greater than 90 days and Accruing	520	1,956
Business Activities Loans | Residential | Construction
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0	10
Current	5,177	11,168
Total loans	5,177	11,178
Past Due greater than 90 days and Accruing	0	0
Business Activities Loans | Residential | 1-4 family
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	4,840	6,273
Current	1,803,184	1,577,521
Total loans	1,808,024	1,583,794
Past Due greater than 90 days and Accruing	520	1,956
Business Activities Loans | Residential | 30-59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	2,412	1,403
Business Activities Loans | Residential | 30-59 Days Past Due | Construction
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0	10
Business Activities Loans | Residential | 30-59 Days Past Due | 1-4 family
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	2,412	1,393
Business Activities Loans | Residential | 60-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	242	701
Business Activities Loans | Residential | 60-89 Days Past Due | Construction
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0	0
Business Activities Loans | Residential | 60-89 Days Past Due | 1-4 family
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	242	701
Business Activities Loans | Residential | 90 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	2,186	4,179
Business Activities Loans | Residential | 90 Days Past Due | Construction
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0	0
Business Activities Loans | Residential | 90 Days Past Due | 1-4 family
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	2,186	4,179
Business Activities Loans | Consumer
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	9,011	7,025
Current	889,710	784,864
Total loans	898,721	791,889
Past Due greater than 90 days and Accruing	263	322
Business Activities Loans | Consumer | Home equity
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	3,426	3,080
Current	291,528	310,441
Total loans	294,954	313,521
Past Due greater than 90 days and Accruing	120	306
Business Activities Loans | Consumer | Auto and other
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	5,585	3,945
Current	598,182	474,423
Total loans	603,767	478,368
Past Due greater than 90 days and Accruing	143	16
Business Activities Loans | Consumer | 30-59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	3,833	2,582
Business Activities Loans | Consumer | 30-59 Days Past Due | Home equity
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	444	99
Business Activities Loans | Consumer | 30-59 Days Past Due | Auto and other
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	3,389	2,483
Business Activities Loans | Consumer | 60-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	1,834	494
Business Activities Loans | Consumer | 60-89 Days Past Due | Home equity
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	1,235	0
Business Activities Loans | Consumer | 60-89 Days Past Due | Auto and other
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	599	494
Business Activities Loans | Consumer | 90 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	3,344	3,949
Business Activities Loans | Consumer | 90 Days Past Due | Home equity
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	1,747	2,981
Business Activities Loans | Consumer | 90 Days Past Due | Auto and other
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	$ 1,597	$ 968

LOANS - Summary of Past Due L72

LOANS - Summary of Past Due Loans for Acquired Loans (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-accrual loans	$ 22,816	$ 22,157
Total loans	8,299,338	6,549,787
Commercial real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-accrual loans	7,267	5,883
Total loans	3,264,742	2,616,438
Commercial real estate | Construction
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-accrual loans	0	0
Total loans	266,336	287,509
Commercial real estate | Single and multi-family
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-accrual loans	654	906
Total loans	423,165	317,491
Commercial real estate | Other
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-accrual loans	6,613	4,977
Total loans	2,575,241	2,011,438
Commercial and industrial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-accrual loans	7,228	7,440
Total loans	1,803,939	1,062,038
Residential
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-accrual loans	2,883	3,795
Total loans	2,102,807	1,893,131
Residential | Construction
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-accrual loans	0	0
Total loans	5,410	11,982
Residential | 1-4 family
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-accrual loans	2,883	3,795
Total loans	2,097,397	1,881,149
Consumer
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-accrual loans	5,438	5,039
Total loans	1,127,850	978,180
Consumer | Home equity
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-accrual loans	3,592	3,192
Total loans	410,181	393,800
Consumer | Auto and other
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-accrual loans	1,846	1,847
Total loans	717,669	584,380
Acquired Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-accrual loans	7,157	5,341
Total Past Due	16,667	12,730
Acquired Credit Impaired	97,344	46,816
Total loans	2,187,140	1,328,480
Past Due greater than 90 days and Accruing	200	1,611
Acquired Loans | Commercial real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-accrual loans	2,250	1,202
Total Past Due	5,721	2,759
Acquired Credit Impaired	53,302	34,820
Total loans	1,047,035	690,094
Past Due greater than 90 days and Accruing	109	0
Acquired Loans | Commercial real estate | Construction
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-accrual loans	0	0
Total Past Due	0	0
Acquired Credit Impaired	7,655	47
Total loans	84,965	34,207
Past Due greater than 90 days and Accruing	0	0
Acquired Loans | Commercial real estate | Single and multi-family
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-accrual loans	203	437
Total Past Due	874	439
Acquired Credit Impaired	2,846	4,726
Total loans	206,082	125,672
Past Due greater than 90 days and Accruing	0	0
Acquired Loans | Commercial real estate | Other
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-accrual loans	2,047	765
Total Past Due	4,847	2,320
Acquired Credit Impaired	42,801	30,047
Total loans	755,988	530,215
Past Due greater than 90 days and Accruing	109
Acquired Loans | Commercial and industrial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-accrual loans	1,333	1,155
Total Past Due	2,959	3,127
Acquired Credit Impaired	34,629	3,369
Total loans	621,370	153,936
Past Due greater than 90 days and Accruing	23	24
Acquired Loans | Residential
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-accrual loans	1,217	1,572
Total Past Due	4,785	2,679
Acquired Credit Impaired	6,974	7,283
Total loans	289,606	298,159
Past Due greater than 90 days and Accruing	30	443
Acquired Loans | Residential | Construction
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-accrual loans	0	0
Total Past Due	0	0
Acquired Credit Impaired	0	0
Total loans	233	804
Past Due greater than 90 days and Accruing	0	0
Acquired Loans | Residential | 1-4 family
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-accrual loans	1,217	1,572
Total Past Due	4,785	2,679
Acquired Credit Impaired	6,974	7,283
Total loans	289,373	297,355
Past Due greater than 90 days and Accruing	30	443
Acquired Loans | Consumer
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-accrual loans	2,357	1,412
Total Past Due	3,202	4,165
Acquired Credit Impaired	2,439	1,344
Total loans	229,129	186,291
Past Due greater than 90 days and Accruing	38	1,144
Acquired Loans | Consumer | Home equity
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-accrual loans	1,965	517
Total Past Due	2,291	1,623
Acquired Credit Impaired	1,956	957
Total loans	115,227	80,279
Past Due greater than 90 days and Accruing	0	353
Acquired Loans | Consumer | Auto and other
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-accrual loans	392	895
Total Past Due	911	2,542
Acquired Credit Impaired	483	387
Total loans	113,902	106,012
Past Due greater than 90 days and Accruing	38	791
Acquired Loans | 30-59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	4,328	5,023
Acquired Loans | 30-59 Days Past Due | Commercial real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	1,487	1,557
Acquired Loans | 30-59 Days Past Due | Commercial real estate | Construction
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0	0
Acquired Loans | 30-59 Days Past Due | Commercial real estate | Single and multi-family
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	671	2
Acquired Loans | 30-59 Days Past Due | Commercial real estate | Other
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	816	1,555
Acquired Loans | 30-59 Days Past Due | Commercial and industrial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	1,252	1,850
Acquired Loans | 30-59 Days Past Due | Residential
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	957	321
Acquired Loans | 30-59 Days Past Due | Residential | Construction
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0	0
Acquired Loans | 30-59 Days Past Due | Residential | 1-4 family
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	957	321
Acquired Loans | 30-59 Days Past Due | Consumer
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	632	1,295
Acquired Loans | 30-59 Days Past Due | Consumer | Home equity
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	286	753
Acquired Loans | 30-59 Days Past Due | Consumer | Auto and other
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	346	542
Acquired Loans | 60-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	4,899	672
Acquired Loans | 60-89 Days Past Due | Commercial real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	1,875	0
Acquired Loans | 60-89 Days Past Due | Commercial real estate | Construction
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0	0
Acquired Loans | 60-89 Days Past Due | Commercial real estate | Single and multi-family
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0	0
Acquired Loans | 60-89 Days Past Due | Commercial real estate | Other
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	1,875	0
Acquired Loans | 60-89 Days Past Due | Commercial and industrial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	268	15
Acquired Loans | 60-89 Days Past Due | Residential
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	2,581	343
Acquired Loans | 60-89 Days Past Due | Residential | Construction
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0	0
Acquired Loans | 60-89 Days Past Due | Residential | 1-4 family
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	2,581	343
Acquired Loans | 60-89 Days Past Due | Consumer
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	175	314
Acquired Loans | 60-89 Days Past Due | Consumer | Home equity
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	40	0
Acquired Loans | 60-89 Days Past Due | Consumer | Auto and other
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	135	314
Acquired Loans | 90 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	7,440	7,035
Acquired Loans | 90 Days Past Due | Commercial real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	2,359	1,202
Acquired Loans | 90 Days Past Due | Commercial real estate | Construction
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0	0
Acquired Loans | 90 Days Past Due | Commercial real estate | Single and multi-family
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	203	437
Acquired Loans | 90 Days Past Due | Commercial real estate | Other
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	2,156	765
Acquired Loans | 90 Days Past Due | Commercial and industrial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	1,439	1,262
Acquired Loans | 90 Days Past Due | Residential
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	1,247	2,015
Acquired Loans | 90 Days Past Due | Residential | Construction
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0	0
Acquired Loans | 90 Days Past Due | Residential | 1-4 family
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	1,247	2,015
Acquired Loans | 90 Days Past Due | Consumer
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	2,395	2,556
Acquired Loans | 90 Days Past Due | Consumer | Home equity
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	1,965	870
Acquired Loans | 90 Days Past Due | Consumer | Auto and other
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	430	1,686
Acquired Impaired Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-accrual loans	$ 83	$ 83

LOANS - Non-accrual Loans (Deta

LOANS - Non-accrual Loans (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total non-accrual loans	$ 22,816	$ 22,157
Business Activities Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total non-accrual loans	15,659	16,816
Acquired Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total non-accrual loans	7,157	5,341
Commercial real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total non-accrual loans	7,267	5,883
Commercial real estate | Business Activities Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total non-accrual loans	5,017	4,681
Commercial real estate | Acquired Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total non-accrual loans	2,250	1,202
Commercial real estate | Construction
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total non-accrual loans	0	0
Commercial real estate | Construction | Business Activities Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total non-accrual loans	0	0
Commercial real estate | Construction | Acquired Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total non-accrual loans	0	0
Commercial real estate | Single and multi-family
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total non-accrual loans	654	906
Commercial real estate | Single and multi-family | Business Activities Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total non-accrual loans	451	469
Commercial real estate | Single and multi-family | Acquired Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total non-accrual loans	203	437
Commercial real estate | Other
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total non-accrual loans	6,613	4,977
Commercial real estate | Other | Business Activities Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total non-accrual loans	4,566	4,212
Commercial real estate | Other | Acquired Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total non-accrual loans	2,047	765
Commercial and industrial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total non-accrual loans	7,228	7,440
Commercial and industrial | Business Activities Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total non-accrual loans	5,895	6,285
Commercial and industrial | Acquired Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total non-accrual loans	1,333	1,155
Residential
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total non-accrual loans	2,883	3,795
Residential | Business Activities Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total non-accrual loans	1,666	2,223
Residential | Acquired Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total non-accrual loans	1,217	1,572
Residential | Construction
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total non-accrual loans	0	0
Residential | Construction | Business Activities Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total non-accrual loans	0	0
Residential | Construction | Acquired Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total non-accrual loans	0	0
Residential | 1-4 family
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total non-accrual loans	2,883	3,795
Residential | 1-4 family | Business Activities Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total non-accrual loans	1,666	2,223
Residential | 1-4 family | Acquired Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total non-accrual loans	1,217	1,572
Consumer
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total non-accrual loans	5,438	5,039
Consumer | Business Activities Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total non-accrual loans	3,081	3,627
Consumer | Acquired Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total non-accrual loans	2,357	1,412
Consumer | Home equity
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total non-accrual loans	3,592	3,192
Consumer | Home equity | Business Activities Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total non-accrual loans	1,627	2,675
Consumer | Home equity | Acquired Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total non-accrual loans	1,965	517
Consumer | Auto and other
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total non-accrual loans	1,846	1,847
Consumer | Auto and other | Business Activities Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total non-accrual loans	1,454	952
Consumer | Auto and other | Acquired Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total non-accrual loans	$ 392	$ 895

LOANS - Loans Evaluated for Imp

LOANS - Loans Evaluated for Impairment (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Allowance for loan losses
Total loans	$ 8,299,338	$ 6,549,787
Business Activities Loans
Allowance for loan losses
Individually evaluated for impairment	43,365	36,732
Collectively evaluated	6,068,833	5,184,575
Total loans	6,112,198	5,221,307
Acquired Loans
Allowance for loan losses
Individually evaluated for impairment	7,309	5,605
Purchased credit-impaired loans	97,344	46,816
Collectively evaluated	2,082,487	1,276,059
Total loans	2,187,140	1,328,480
Commercial real estate
Allowance for loan losses
Total loans	3,264,742	2,616,438
Commercial real estate | Business Activities Loans
Allowance for loan losses
Individually evaluated for impairment	33,732	25,549
Collectively evaluated	2,183,975	1,900,795
Total loans	2,217,707	1,926,344
Commercial real estate | Acquired Loans
Allowance for loan losses
Individually evaluated for impairment	4,244	4,256
Purchased credit-impaired loans	53,302	34,820
Collectively evaluated	989,489	651,018
Total loans	1,047,035	690,094
Commercial and industrial
Allowance for loan losses
Total loans	1,803,939	1,062,038
Commercial and industrial | Business Activities Loans
Allowance for loan losses
Individually evaluated for impairment	5,761	5,705
Collectively evaluated	1,176,808	902,397
Total loans	1,182,569	908,102
Commercial and industrial | Acquired Loans
Allowance for loan losses
Individually evaluated for impairment	421	635
Purchased credit-impaired loans	34,629	3,369
Collectively evaluated	586,320	149,932
Total loans	621,370	153,936
Residential mortgages
Allowance for loan losses
Total loans	2,102,807	1,893,131
Residential mortgages | Business Activities Loans
Allowance for loan losses
Individually evaluated for impairment	3,872	2,775
Collectively evaluated	1,809,329	1,592,197
Total loans	1,813,201	1,594,972
Residential mortgages | Acquired Loans
Allowance for loan losses
Individually evaluated for impairment	2,617	308
Purchased credit-impaired loans	6,974	7,283
Collectively evaluated	280,015	290,568
Total loans	289,606	298,159
Consumer
Allowance for loan losses
Total loans	1,127,850	978,180
Consumer | Business Activities Loans
Allowance for loan losses
Individually evaluated for impairment	0	2,703
Collectively evaluated	898,721	789,186
Total loans	898,721	791,889
Consumer | Acquired Loans
Allowance for loan losses
Individually evaluated for impairment	27	406
Purchased credit-impaired loans	2,439	1,344
Collectively evaluated	226,663	184,541
Total loans	$ 229,129	$ 186,291

LOANS - Summary of Impaired Loa

LOANS - Summary of Impaired Loans (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Business Activities Loans
Impaired Financing Receivable, Recorded Investment [Abstract]
Total	$ 43,679	$ 36,018
Impaired Financing Receivable, Unpaid Principal Balance [Abstract]
Total	49,702	36,732
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Related Allowance	460	714
Business Activities Loans | Commercial real estate
Impaired Financing Receivable, Recorded Investment [Abstract]
Total	34,001	25,390
Impaired Financing Receivable, Unpaid Principal Balance [Abstract]
Total	37,783	25,548
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Related Allowance	229	158
Business Activities Loans | Commercial real estate | Construction
Impaired Financing Receivable, Recorded Investment [Abstract]
With no related allowance	0
With an allowance recorded	159
Impaired Financing Receivable, Unpaid Principal Balance [Abstract]
With no related allowance	0
With an allowance recorded	159
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Related Allowance	1
Business Activities Loans | Commercial real estate | Other
Impaired Financing Receivable, Recorded Investment [Abstract]
With no related allowance	18,285	18,905
With an allowance recorded	14,321	6,306
Impaired Financing Receivable, Unpaid Principal Balance [Abstract]
With no related allowance	18,611	18,905
With an allowance recorded	15,235	6,462
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Related Allowance	227	156
Business Activities Loans | Commercial real estate | Single and multi-family
Impaired Financing Receivable, Recorded Investment [Abstract]
With no related allowance	1,077
With an allowance recorded	159	179
Impaired Financing Receivable, Unpaid Principal Balance [Abstract]
With no related allowance	3,607
With an allowance recorded	171	181
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Related Allowance	1	2
Business Activities Loans | Commercial and industrial
Impaired Financing Receivable, Recorded Investment [Abstract]
Total	5,776	5,442
Impaired Financing Receivable, Unpaid Principal Balance [Abstract]
Total	6,878	5,706
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Related Allowance	66	264
Business Activities Loans | Commercial and industrial | Other
Impaired Financing Receivable, Recorded Investment [Abstract]
With no related allowance	2,060	382
With an allowance recorded	3,716	5,060
Impaired Financing Receivable, Unpaid Principal Balance [Abstract]
With no related allowance	2,629	382
With an allowance recorded	4,249	5,324
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Related Allowance	66	264
Business Activities Loans | Residential
Impaired Financing Receivable, Recorded Investment [Abstract]
Total	2,004	2,639
Impaired Financing Receivable, Unpaid Principal Balance [Abstract]
Total	2,521	2,775
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Related Allowance	130	136
Business Activities Loans | Residential | 1-4 family
Impaired Financing Receivable, Recorded Investment [Abstract]
With no related allowance	660	2,101
With an allowance recorded	1,344	538
Impaired Financing Receivable, Unpaid Principal Balance [Abstract]
With no related allowance	1,075	2,101
With an allowance recorded	1,446	674
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Related Allowance	130	136
Business Activities Loans | Consumer
Impaired Financing Receivable, Recorded Investment [Abstract]
Total	1,898	2,547
Impaired Financing Receivable, Unpaid Principal Balance [Abstract]
Total	2,520	2,703
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Related Allowance	35	156
Business Activities Loans | Consumer | Other
Impaired Financing Receivable, Recorded Investment [Abstract]
With an allowance recorded	17
Impaired Financing Receivable, Unpaid Principal Balance [Abstract]
With an allowance recorded	17
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Related Allowance	1
Business Activities Loans | Consumer | Home equity
Impaired Financing Receivable, Recorded Investment [Abstract]
With no related allowance	867	1,605
With an allowance recorded	1,014	942
Impaired Financing Receivable, Unpaid Principal Balance [Abstract]
With no related allowance	1,504	1,605
With an allowance recorded	999	1,098
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Related Allowance	34	156
Acquired Loans
Impaired Financing Receivable, Recorded Investment [Abstract]
Total	7,335	5,171
Impaired Financing Receivable, Unpaid Principal Balance [Abstract]
Total	9,178	5,605
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Related Allowance	111	434
Acquired Loans | Commercial real estate
Impaired Financing Receivable, Recorded Investment [Abstract]
Total	4,257	4,006
Impaired Financing Receivable, Unpaid Principal Balance [Abstract]
Total	5,625	4,256
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Related Allowance	56	250
Acquired Loans | Commercial real estate | Other
Impaired Financing Receivable, Recorded Investment [Abstract]
With no related allowance	1,123	547
With an allowance recorded	2,043	2,209
Impaired Financing Receivable, Unpaid Principal Balance [Abstract]
With no related allowance	2,794	547
With an allowance recorded	1,661	2,351
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Related Allowance	38	142
Acquired Loans | Commercial real estate | Single and multi-family
Impaired Financing Receivable, Recorded Investment [Abstract]
With no related allowance	204
With an allowance recorded	887	1,250
Impaired Financing Receivable, Unpaid Principal Balance [Abstract]
With no related allowance	290
With an allowance recorded	880	1,358
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Related Allowance	18	108
Acquired Loans | Commercial and industrial
Impaired Financing Receivable, Recorded Investment [Abstract]
Total	420	576
Impaired Financing Receivable, Unpaid Principal Balance [Abstract]
Total	476	635
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Related Allowance	1	59
Acquired Loans | Commercial and industrial | Other
Impaired Financing Receivable, Recorded Investment [Abstract]
With no related allowance	255
With an allowance recorded	165	576
Impaired Financing Receivable, Unpaid Principal Balance [Abstract]
With no related allowance	310
With an allowance recorded	166	635
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Related Allowance	1	59
Acquired Loans | Residential
Impaired Financing Receivable, Recorded Investment [Abstract]
Total	824	297
Impaired Financing Receivable, Unpaid Principal Balance [Abstract]
Total	856	308
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Related Allowance	9	11
Acquired Loans | Residential | 1-4 family
Impaired Financing Receivable, Recorded Investment [Abstract]
With no related allowance	658	208
With an allowance recorded	166	89
Impaired Financing Receivable, Unpaid Principal Balance [Abstract]
With no related allowance	671	208
With an allowance recorded	185	100
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Related Allowance	9	11
Acquired Loans | Consumer
Impaired Financing Receivable, Recorded Investment [Abstract]
Total	1,834	292
Impaired Financing Receivable, Unpaid Principal Balance [Abstract]
Total	2,221	406
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Related Allowance	45	114
Acquired Loans | Consumer | Other
Impaired Financing Receivable, Recorded Investment [Abstract]
With no related allowance	27	0
Impaired Financing Receivable, Unpaid Principal Balance [Abstract]
With no related allowance	27	0
Acquired Loans | Consumer | Home equity
Impaired Financing Receivable, Recorded Investment [Abstract]
With no related allowance	1,374	0
With an allowance recorded	433	292
Impaired Financing Receivable, Unpaid Principal Balance [Abstract]
With no related allowance	1,654	0
With an allowance recorded	540	406
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Related Allowance	$ 45	$ 114

LOANS - Summary of Average Reco

LOANS - Summary of Average Recorded Investment and Interst Income Recognized (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Business Activities Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average Recorded Investment	$ 45,269	$ 24,242	$ 26,380
Cash Basis Interest Income Recognized	2,557	2,028	867
Business Activities Loans | Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average Recorded Investment	32,790	14,090	18,006
Cash Basis Interest Income Recognized	1,872	1,511	526
Business Activities Loans | Commercial real estate | Construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average recorded investment, with no related allowance	0	0	2,245
Cash basis interest income recognized, with no related allowance	0	0	92
Average recorded investment with related allowance	41	0	0
Cash basis interest income recognized, with related allowance	3	0	0
Business Activities Loans | Commercial real estate | Single and multi-family
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average recorded investment, with no related allowance	341	36	60
Cash basis interest income recognized, with no related allowance	214	1	0
Average recorded investment with related allowance	169	15	0
Cash basis interest income recognized, with related allowance	12	6	0
Business Activities Loans | Commercial real estate | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average recorded investment, with no related allowance	20,867	6,463	12,487
Cash basis interest income recognized, with no related allowance	1,123	1,155	302
Average recorded investment with related allowance	11,372	7,576	3,214
Cash basis interest income recognized, with related allowance	520	349	132
Business Activities Loans | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average Recorded Investment	7,688	5,351	4,680
Cash Basis Interest Income Recognized	532	356	214
Business Activities Loans | Commercial and industrial | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average recorded investment, with no related allowance	4,437	3,349	3,870
Cash basis interest income recognized, with no related allowance	265	131	177
Average recorded investment with related allowance	3,251	2,002	810
Cash basis interest income recognized, with related allowance	267	225	37
Business Activities Loans | Residential
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average Recorded Investment	2,417	3,085	3,057
Cash Basis Interest Income Recognized	90	117	110
Business Activities Loans | Residential | 1-4 family
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average recorded investment, with no related allowance	1,128	2,403	1,353
Cash basis interest income recognized, with no related allowance	31	91	38
Average recorded investment with related allowance	1,289	682	1,704
Cash basis interest income recognized, with related allowance	59	26	72
Business Activities Loans | Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average Recorded Investment	2,374	1,716	637
Cash Basis Interest Income Recognized	63	44	17
Business Activities Loans | Consumer | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average recorded investment, with no related allowance	72	2	0
Cash basis interest income recognized, with no related allowance	3	0	0
Average recorded investment with related allowance	4	103	112
Cash basis interest income recognized, with related allowance	1	4	4
Business Activities Loans | Consumer | Home equity
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average recorded investment, with no related allowance	1,291	612	442
Cash basis interest income recognized, with no related allowance	30	5	13
Average recorded investment with related allowance	1,007	999	83
Cash basis interest income recognized, with related allowance	29	35	0
Acquired Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average Recorded Investment	5,822	5,676	7,391
Cash Basis Interest Income Recognized	596	364	318
Acquired Loans | Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average Recorded Investment	3,451	4,203	6,187
Cash Basis Interest Income Recognized	459	300	283
Acquired Loans | Commercial real estate | Construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average recorded investment, with no related allowance	0	0	445
Cash basis interest income recognized, with no related allowance	0	0	60
Average recorded investment with related allowance	0	0	0
Cash basis interest income recognized, with related allowance	0	0	0
Acquired Loans | Commercial real estate | Single and multi-family
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average recorded investment, with no related allowance	342	0	2,014
Cash basis interest income recognized, with no related allowance	82	0	57
Average recorded investment with related allowance	903	1,064	623
Cash basis interest income recognized, with related allowance	47	115	33
Acquired Loans | Commercial real estate | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average recorded investment, with no related allowance	487	521	1,721
Cash basis interest income recognized, with no related allowance	239	20	37
Average recorded investment with related allowance	1,719	2,618	1,384
Cash basis interest income recognized, with related allowance	91	165	96
Acquired Loans | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average Recorded Investment	628	861	31
Cash Basis Interest Income Recognized	56	26	3
Acquired Loans | Commercial and industrial | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average recorded investment, with no related allowance	581	492	0
Cash basis interest income recognized, with no related allowance	43	9	0
Average recorded investment with related allowance	47	369	31
Cash basis interest income recognized, with related allowance	13	17	3
Acquired Loans | Residential
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average Recorded Investment	563	507	767
Cash Basis Interest Income Recognized	37	37	15
Acquired Loans | Residential | 1-4 family
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average recorded investment, with no related allowance	390	293	463
Cash basis interest income recognized, with no related allowance	28	12	6
Average recorded investment with related allowance	173	214	304
Cash basis interest income recognized, with related allowance	9	25	9
Acquired Loans | Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average Recorded Investment	1,180	105	406
Cash Basis Interest Income Recognized	44	1	17
Acquired Loans | Consumer | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average recorded investment, with no related allowance	7	105	59
Cash basis interest income recognized, with no related allowance	1	1	5
Acquired Loans | Consumer | Home equity
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average recorded investment, with no related allowance	773	0	152
Cash basis interest income recognized, with no related allowance	22	0	5
Average recorded investment with related allowance	400	0	195
Cash basis interest income recognized, with related allowance	$ 21	$ 0	$ 7

LOANS - Modifications by Class

LOANS - Modifications by Class (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2017USD ($)modification	Dec. 31, 2016USD ($)modification	Dec. 31, 2015USD ($)modification
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of modifications (modification) | modification	35	17	14
Pre-Modification Outstanding Recorded Investment	$ 17,640	$ 17,765	$ 19,047
Post-Modification Outstanding Recorded Investment	$ 15,896	$ 17,765	$ 17,607
Commercial loans | Construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of modifications (modification) | modification			1
Pre-Modification Outstanding Recorded Investment			$ 123
Post-Modification Outstanding Recorded Investment			$ 123
Commercial loans | Single and multi-family
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of modifications (modification) | modification	1	5	2
Pre-Modification Outstanding Recorded Investment	$ 235	$ 437	$ 307
Post-Modification Outstanding Recorded Investment	$ 235	$ 437	$ 307
Commercial loans | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of modifications (modification) | modification	15	5	4
Pre-Modification Outstanding Recorded Investment	$ 13,445	$ 16,651	$ 8,577
Post-Modification Outstanding Recorded Investment	$ 11,718	$ 16,651	$ 7,274
Commercial and industrial | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of modifications (modification) | modification	12	4	6
Pre-Modification Outstanding Recorded Investment	$ 3,507	$ 555	$ 9,041
Post-Modification Outstanding Recorded Investment	$ 3,507	$ 555	$ 8,904
Residential | 1-4 family
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of modifications (modification) | modification	4	2
Pre-Modification Outstanding Recorded Investment	$ 331	$ 5
Post-Modification Outstanding Recorded Investment	$ 314	$ 5
Consumer | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of modifications (modification) | modification			1
Pre-Modification Outstanding Recorded Investment			$ 999
Post-Modification Outstanding Recorded Investment			$ 999
Consumer | Home equity
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of modifications (modification) | modification	3	1
Pre-Modification Outstanding Recorded Investment	$ 122	$ 117
Post-Modification Outstanding Recorded Investment	$ 122	$ 117

LOANS - Modifications that Subs

LOANS - Modifications that Subsequently Defaulted (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2017USD ($)contract	Dec. 31, 2016contract	Dec. 31, 2015USD ($)contract
Accounts, Notes, Loans and Financing Receivable [Line Items]
Modifications that subsequently defaulted, number of contracts (contract) | contract	3	0	8
Modifications that subsequently defaulted, recorded investment | $	$ 605		$ 7,121
Commercial loans | Single and multi-family
Accounts, Notes, Loans and Financing Receivable [Line Items]
Modifications that subsequently defaulted, number of contracts (contract) | contract	0		1
Modifications that subsequently defaulted, recorded investment | $	$ 0		$ 0
Commercial loans | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Modifications that subsequently defaulted, number of contracts (contract) | contract	1		1
Modifications that subsequently defaulted, recorded investment | $	$ 113		$ 373
Commercial and industrial | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Modifications that subsequently defaulted, number of contracts (contract) | contract	2		4
Modifications that subsequently defaulted, recorded investment | $	$ 492		$ 6,579
Residential | 1-4 family
Accounts, Notes, Loans and Financing Receivable [Line Items]
Modifications that subsequently defaulted, number of contracts (contract) | contract	0		2
Modifications that subsequently defaulted, recorded investment | $	$ 0		$ 169

LOANS - Summary of TDR Activity

LOANS - Summary of TDR Activity (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Trouble Debt Restructuring on Financing Receivables [Roll Forward]
Balance at beginning of year	$ 33,829	$ 22,048	$ 16,714
Principal payments	(3,213)	(5,870)	(5,460)
TDR status change	0	2,235	0
Other reductions	(4,522)	(2,349)	(3,160)
Newly identified TDRs	15,896	17,765	13,954
Balance at end of year	$ 41,990	$ 33,829	$ 22,048

LOAN LOSS ALLOWANCE (Details)

LOAN LOSS ALLOWANCE (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	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Activity in the allowance for loan losses
Balance at beginning of year				$ 43,998					$ 43,998
Provision for loan losses	$ 6,141	$ 4,900	$ 4,889	5,095	$ 4,100	$ 4,734	$ 4,522	$ 4,006	21,025	$ 17,362	$ 16,726
Balance at end of year	51,834				43,998				51,834	43,998
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Total	51,834			43,998	43,998				43,998	43,998		$ 51,834	$ 43,998
Business Activities Loans
Activity in the allowance for loan losses
Balance at beginning of year				39,229				34,574	39,229	34,574	32,795
Charged-off loans									11,524	10,505	11,621
Recoveries on charged-off loans									889	792	759
Provision for loan losses									17,326	14,368	12,641
Balance at end of year	45,920				39,229				45,920	39,229	34,574
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Individually evaluated for impairment												460	714	$ 426
Collectively evaluated												45,460	38,515	34,148
Total	45,920			39,229	39,229			34,574	39,229	34,574	32,795	45,920	39,229	34,574
Acquired Loans
Activity in the allowance for loan losses
Balance at beginning of year				4,769				4,734	4,769	4,734	2,867
Charged-off loans									3,060	3,521	3,067
Recoveries on charged-off loans									506	562	849
Provision for loan losses									3,699	2,994	4,085
Balance at end of year	5,914				4,769				5,914	4,769	4,734
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Individually evaluated for impairment												111	434	98
Purchased credit-impaired loans														42
Collectively evaluated												5,803	4,335	4,594
Total	5,914			4,769	4,769			4,734	4,769	4,734	2,867	5,914	4,769	4,734
Commercial real estate | Business Activities Loans
Activity in the allowance for loan losses
Balance at beginning of year				16,498				14,591	16,498	14,591	14,740
Charged-off loans									3,875	2,127	6,865
Recoveries on charged-off loans									170	243	164
Provision for loan losses									4,050	3,791	6,552
Balance at end of year	16,843				16,498				16,843	16,498	14,591
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Individually evaluated for impairment												229	158	149
Collectively evaluated												16,614	16,340	14,442
Total	16,843			16,498	16,498			14,591	16,498	14,591	14,740	16,843	16,498	14,591
Commercial real estate | Acquired Loans
Activity in the allowance for loan losses
Balance at beginning of year				2,303				1,903	2,303	1,903	790
Charged-off loans									771	977	681
Recoveries on charged-off loans									65	61	418
Provision for loan losses									2,259	1,316	1,376
Balance at end of year	3,856				2,303				3,856	2,303	1,903
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Individually evaluated for impairment												56	250	43
Purchased credit-impaired loans														42
Collectively evaluated												3,800	2,053	1,818
Total	3,856			2,303	2,303			1,903	2,303	1,903	790	3,856	2,303	1,903
Commercial and industrial | Business Activities Loans
Activity in the allowance for loan losses
Balance at beginning of year				9,447				7,385	9,447	7,385	5,246
Charged-off loans									3,373	4,620	2,358
Recoveries on charged-off loans									179	123	169
Provision for loan losses									7,597	6,559	4,328
Balance at end of year	13,850				9,447				13,850	9,447	7,385
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Individually evaluated for impairment												66	264	21
Collectively evaluated												13,784	9,183	7,364
Total	13,850			9,447	9,447			7,385	9,447	7,385	5,246	13,850	9,447	7,385
Commercial and industrial | Acquired Loans
Activity in the allowance for loan losses
Balance at beginning of year				1,164				1,330	1,164	1,330	1,093
Charged-off loans									844	1,095	752
Recoveries on charged-off loans									245	266	289
Provision for loan losses									560	663	700
Balance at end of year	1,125				1,164				1,125	1,164	1,330
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Individually evaluated for impairment												1	59	0
Purchased credit-impaired loans														0
Collectively evaluated												1,124	1,105	1,330
Total	1,125			1,164	1,164			1,330	1,164	1,330	1,093	1,125	1,164	1,330
Residential mortgages | Business Activities Loans
Activity in the allowance for loan losses
Balance at beginning of year				7,805				7,613	7,805	7,613	6,864
Charged-off loans									806	2,036	1,215
Recoveries on charged-off loans									270	159	141
Provision for loan losses									2,151	2,069	1,823
Balance at end of year	9,420				7,805				9,420	7,805	7,613
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Individually evaluated for impairment												130	136	153
Collectively evaluated												9,290	7,669	7,460
Total	9,420			7,805	7,805			7,613	7,805	7,613	6,864	9,420	7,805	7,613
Residential mortgages | Acquired Loans
Activity in the allowance for loan losses
Balance at beginning of year				766				976	766	976	615
Charged-off loans									797	829	642
Recoveries on charged-off loans									43	144	64
Provision for loan losses									586	475	939
Balance at end of year	598				766				598	766	976
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Individually evaluated for impairment												9	11	30
Purchased credit-impaired loans														0
Collectively evaluated												589	755	946
Total	598			766	766			976	766	976	615	598	766	976
Consumer | Business Activities Loans
Activity in the allowance for loan losses
Balance at beginning of year				5,479				4,985	5,479	4,985	5,945
Charged-off loans									3,470	1,722	1,183
Recoveries on charged-off loans									270	267	285
Provision for loan losses									3,528	1,949	(62)
Balance at end of year	5,807				5,479				5,807	5,479	4,985
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Individually evaluated for impairment												35	156	103
Collectively evaluated												5,772	5,323	4,882
Total	5,807			5,479	5,479			4,985	5,479	4,985	5,945	5,807	5,479	4,985
Consumer | Acquired Loans
Activity in the allowance for loan losses
Balance at beginning of year				536				525	536	525	369
Charged-off loans									648	620	992
Recoveries on charged-off loans									153	91	78
Provision for loan losses									294	540	1,070
Balance at end of year	335				536				335	536	525
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Individually evaluated for impairment												45	114	25
Purchased credit-impaired loans														0
Collectively evaluated												290	422	500
Total	$ 335			$ 536	$ 536			$ 525	$ 536	$ 525	$ 369	$ 335	$ 536	$ 525

LOAN LOSS ALLOWANCE - Narrative

LOAN LOSS ALLOWANCE - Narrative (Details)	12 Months Ended
	Dec. 31, 2017grade
Business Activities Loans
Financing Receivable, Recorded Investment [Line Items]
Number of grades in internal loan rating system (grade)	3
Business Activities Loans | Residential | Mortgages | Pass
Financing Receivable, Recorded Investment [Line Items]
Period within which loans are current, based on which risk rating is assigned	59 days
Business Activities Loans | Residential | Mortgages | Special mention | Minimum
Financing Receivable, Recorded Investment [Line Items]
Delinquency period of loans based on which risk rating is assigned	60 days
Business Activities Loans | Residential | Mortgages | Special mention | Maximum
Financing Receivable, Recorded Investment [Line Items]
Delinquency period of loans based on which risk rating is assigned	89 days
Business Activities Loans | Residential | Mortgages | Substandard
Financing Receivable, Recorded Investment [Line Items]
Delinquency period of loans based on which risk rating is assigned	90 days
Other | Consumer
Financing Receivable, Recorded Investment [Line Items]
Number of grades in internal loan rating system (grade)	2
Other | Consumer | Performing
Financing Receivable, Recorded Investment [Line Items]
Period within which loans are current, based on which risk rating is assigned	119 days
Other | Consumer | Nonperforming
Financing Receivable, Recorded Investment [Line Items]
Delinquency period of loans based on which risk rating is assigned	120 days

LOAN LOSS ALLOWANCE - Loans by

LOAN LOSS ALLOWANCE - Loans by Risk Rating (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Financing Receivable, Recorded Investment [Line Items]
Loans	$ 8,299,338	$ 6,549,787
Special mention
Financing Receivable, Recorded Investment [Line Items]
Loans	55,189	11,802
Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans	110,258	95,302
Commercial real estate
Financing Receivable, Recorded Investment [Line Items]
Loans	3,264,742	2,616,438
Commercial real estate | Construction
Financing Receivable, Recorded Investment [Line Items]
Loans	266,336	287,509
Commercial real estate | Single and multi-family
Financing Receivable, Recorded Investment [Line Items]
Loans	423,165	317,491
Commercial real estate | Other
Financing Receivable, Recorded Investment [Line Items]
Loans	2,575,241	2,011,438
Commercial and industrial
Financing Receivable, Recorded Investment [Line Items]
Loans	1,803,939	1,062,038
Residential mortgages
Financing Receivable, Recorded Investment [Line Items]
Loans	2,102,807	1,893,131
Residential mortgages | Construction
Financing Receivable, Recorded Investment [Line Items]
Loans	5,410	11,982
Residential mortgages | 1-4 family
Financing Receivable, Recorded Investment [Line Items]
Loans	2,097,397	1,881,149
Consumer loans
Financing Receivable, Recorded Investment [Line Items]
Loans	1,127,850	978,180
Consumer loans | Home equity
Financing Receivable, Recorded Investment [Line Items]
Loans	410,181	393,800
Consumer loans | Auto and other
Financing Receivable, Recorded Investment [Line Items]
Loans	717,669	584,380
Business Activities Loans
Financing Receivable, Recorded Investment [Line Items]
Loans	6,112,198	5,221,307
Business Activities Loans | Special mention
Financing Receivable, Recorded Investment [Line Items]
Loans	28,387	7,479
Business Activities Loans | Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans	36,846	51,125
Business Activities Loans | Commercial real estate
Financing Receivable, Recorded Investment [Line Items]
Loans	2,217,707	1,926,344
Business Activities Loans | Commercial real estate | Construction
Financing Receivable, Recorded Investment [Line Items]
Loans	181,371	253,302
Business Activities Loans | Commercial real estate | Single and multi-family
Financing Receivable, Recorded Investment [Line Items]
Loans	217,083	191,819
Business Activities Loans | Commercial real estate | Real Estate
Financing Receivable, Recorded Investment [Line Items]
Loans	1,819,253	1,481,223
Business Activities Loans | Commercial real estate | Other
Financing Receivable, Recorded Investment [Line Items]
Loans	1,819,253	1,481,223
Business Activities Loans | Commercial real estate | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans	2,170,751	1,877,374
Business Activities Loans | Commercial real estate | Pass | Construction
Financing Receivable, Recorded Investment [Line Items]
Loans	181,371	253,302
Business Activities Loans | Commercial real estate | Pass | Single and multi-family
Financing Receivable, Recorded Investment [Line Items]
Loans	214,289	189,310
Business Activities Loans | Commercial real estate | Pass | Real Estate
Financing Receivable, Recorded Investment [Line Items]
Loans	1,775,091	1,434,762
Business Activities Loans | Commercial real estate | Special mention
Financing Receivable, Recorded Investment [Line Items]
Loans	13,503	6,161
Business Activities Loans | Commercial real estate | Special mention | Construction
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Business Activities Loans | Commercial real estate | Special mention | Single and multi-family
Financing Receivable, Recorded Investment [Line Items]
Loans	504	334
Business Activities Loans | Commercial real estate | Special mention | Real Estate
Financing Receivable, Recorded Investment [Line Items]
Loans	12,999	5,827
Business Activities Loans | Commercial real estate | Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans	33,453	42,773
Business Activities Loans | Commercial real estate | Substandard | Construction
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Business Activities Loans | Commercial real estate | Substandard | Single and multi-family
Financing Receivable, Recorded Investment [Line Items]
Loans	2,290	2,175
Business Activities Loans | Commercial real estate | Substandard | Real Estate
Financing Receivable, Recorded Investment [Line Items]
Loans	31,163	40,598
Business Activities Loans | Commercial real estate | Doubtful
Financing Receivable, Recorded Investment [Line Items]
Loans	0	36
Business Activities Loans | Commercial real estate | Doubtful | Construction
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Business Activities Loans | Commercial real estate | Doubtful | Single and multi-family
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Business Activities Loans | Commercial real estate | Doubtful | Real Estate
Financing Receivable, Recorded Investment [Line Items]
Loans	0	36
Business Activities Loans | Commercial and industrial
Financing Receivable, Recorded Investment [Line Items]
Loans	1,182,569	908,102
Business Activities Loans | Commercial and industrial | Business loans
Financing Receivable, Recorded Investment [Line Items]
Loans	1,182,569	908,102
Business Activities Loans | Commercial and industrial | Business loans | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans	1,156,240	890,974
Business Activities Loans | Commercial and industrial | Business loans | Special mention
Financing Receivable, Recorded Investment [Line Items]
Loans	12,806	123
Business Activities Loans | Commercial and industrial | Business loans | Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans	11,123	13,825
Business Activities Loans | Commercial and industrial | Business loans | Doubtful
Financing Receivable, Recorded Investment [Line Items]
Loans	2,400	3,180
Business Activities Loans | Residential mortgages
Financing Receivable, Recorded Investment [Line Items]
Loans	1,813,201	1,594,972
Business Activities Loans | Residential mortgages | Construction
Financing Receivable, Recorded Investment [Line Items]
Loans	5,177	11,178
Business Activities Loans | Residential mortgages | 1-4 family
Financing Receivable, Recorded Investment [Line Items]
Loans	1,808,024	1,583,794
Business Activities Loans | Residential mortgages | Mortgages
Financing Receivable, Recorded Investment [Line Items]
Loans	1,813,201	1,594,971
Business Activities Loans | Residential mortgages | Mortgages | Construction
Financing Receivable, Recorded Investment [Line Items]
Loans	5,177	11,178
Business Activities Loans | Residential mortgages | Mortgages | 1-4 family
Financing Receivable, Recorded Investment [Line Items]
Loans	1,808,024	1,583,793
Business Activities Loans | Residential mortgages | Mortgages | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans	1,810,773	1,590,091
Business Activities Loans | Residential mortgages | Mortgages | Pass | Construction
Financing Receivable, Recorded Investment [Line Items]
Loans	5,177	11,178
Business Activities Loans | Residential mortgages | Mortgages | Pass | 1-4 family
Financing Receivable, Recorded Investment [Line Items]
Loans	1,805,596	1,578,913
Business Activities Loans | Residential mortgages | Mortgages | Special mention
Financing Receivable, Recorded Investment [Line Items]
Loans	242	701
Business Activities Loans | Residential mortgages | Mortgages | Special mention | Construction
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Business Activities Loans | Residential mortgages | Mortgages | Special mention | 1-4 family
Financing Receivable, Recorded Investment [Line Items]
Loans	242	701
Business Activities Loans | Residential mortgages | Mortgages | Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans	2,186	4,179
Business Activities Loans | Residential mortgages | Mortgages | Substandard | Construction
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Business Activities Loans | Residential mortgages | Mortgages | Substandard | 1-4 family
Financing Receivable, Recorded Investment [Line Items]
Loans	2,186	4,179
Business Activities Loans | Consumer loans
Financing Receivable, Recorded Investment [Line Items]
Loans	898,721	791,889
Business Activities Loans | Consumer loans | Home equity
Financing Receivable, Recorded Investment [Line Items]
Loans	294,954	313,521
Business Activities Loans | Consumer loans | Auto and other
Financing Receivable, Recorded Investment [Line Items]
Loans	603,767	478,368
Business Activities Loans | Consumer loans | Performing
Financing Receivable, Recorded Investment [Line Items]
Loans	895,640	788,262
Business Activities Loans | Consumer loans | Performing | Home equity
Financing Receivable, Recorded Investment [Line Items]
Loans	293,327	310,846
Business Activities Loans | Consumer loans | Performing | Auto and other
Financing Receivable, Recorded Investment [Line Items]
Loans	602,313	477,416
Business Activities Loans | Consumer loans | Nonperforming
Financing Receivable, Recorded Investment [Line Items]
Loans	3,081	3,627
Business Activities Loans | Consumer loans | Nonperforming | Home equity
Financing Receivable, Recorded Investment [Line Items]
Loans	1,627	2,675
Business Activities Loans | Consumer loans | Nonperforming | Auto and other
Financing Receivable, Recorded Investment [Line Items]
Loans	1,454	952
Acquired Loans
Financing Receivable, Recorded Investment [Line Items]
Loans	2,187,140	1,328,480
Acquired Loans | Special mention
Financing Receivable, Recorded Investment [Line Items]
Loans	26,802	4,323
Acquired Loans | Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans	73,412	44,177
Acquired Loans | Commercial real estate
Financing Receivable, Recorded Investment [Line Items]
Loans	1,047,035	690,094
Acquired Loans | Commercial real estate | Construction
Financing Receivable, Recorded Investment [Line Items]
Loans	84,965	34,207
Acquired Loans | Commercial real estate | Single and multi-family
Financing Receivable, Recorded Investment [Line Items]
Loans	206,082	125,672
Acquired Loans | Commercial real estate | Real Estate
Financing Receivable, Recorded Investment [Line Items]
Loans	755,988	530,215
Acquired Loans | Commercial real estate | Other
Financing Receivable, Recorded Investment [Line Items]
Loans	755,988	530,215
Acquired Loans | Commercial real estate | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans	965,081	649,437
Acquired Loans | Commercial real estate | Pass | Construction
Financing Receivable, Recorded Investment [Line Items]
Loans	76,611	33,461
Acquired Loans | Commercial real estate | Pass | Single and multi-family
Financing Receivable, Recorded Investment [Line Items]
Loans	203,624	119,414
Acquired Loans | Commercial real estate | Pass | Real Estate
Financing Receivable, Recorded Investment [Line Items]
Loans	684,846	496,562
Acquired Loans | Commercial real estate | Special mention
Financing Receivable, Recorded Investment [Line Items]
Loans	22,673	2,529
Acquired Loans | Commercial real estate | Special mention | Construction
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Acquired Loans | Commercial real estate | Special mention | Single and multi-family
Financing Receivable, Recorded Investment [Line Items]
Loans	603	907
Acquired Loans | Commercial real estate | Special mention | Real Estate
Financing Receivable, Recorded Investment [Line Items]
Loans	22,070	1,622
Acquired Loans | Commercial real estate | Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans	59,281	38,128
Acquired Loans | Commercial real estate | Substandard | Construction
Financing Receivable, Recorded Investment [Line Items]
Loans	8,354	746
Acquired Loans | Commercial real estate | Substandard | Single and multi-family
Financing Receivable, Recorded Investment [Line Items]
Loans	1,855	5,351
Acquired Loans | Commercial real estate | Substandard | Real Estate
Financing Receivable, Recorded Investment [Line Items]
Loans	49,072	32,031
Acquired Loans | Commercial and industrial
Financing Receivable, Recorded Investment [Line Items]
Loans	621,370	153,936
Acquired Loans | Commercial and industrial | Business loans
Financing Receivable, Recorded Investment [Line Items]
Loans	621,370	153,936
Acquired Loans | Commercial and industrial | Business loans | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans	606,922	147,102
Acquired Loans | Commercial and industrial | Business loans | Special mention
Financing Receivable, Recorded Investment [Line Items]
Loans	1,241	1,260
Acquired Loans | Commercial and industrial | Business loans | Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans	13,207	5,574
Acquired Loans | Residential mortgages
Financing Receivable, Recorded Investment [Line Items]
Loans	289,606	298,159
Acquired Loans | Residential mortgages | Construction
Financing Receivable, Recorded Investment [Line Items]
Loans	233	804
Acquired Loans | Residential mortgages | 1-4 family
Financing Receivable, Recorded Investment [Line Items]
Loans	289,373	297,355
Acquired Loans | Residential mortgages | Mortgages
Financing Receivable, Recorded Investment [Line Items]
Loans	289,606	298,159
Acquired Loans | Residential mortgages | Mortgages | Construction
Financing Receivable, Recorded Investment [Line Items]
Loans	233	804
Acquired Loans | Residential mortgages | Mortgages | 1-4 family
Financing Receivable, Recorded Investment [Line Items]
Loans	289,373	297,355
Acquired Loans | Residential mortgages | Mortgages | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans	281,393	295,787
Acquired Loans | Residential mortgages | Mortgages | Pass | Construction
Financing Receivable, Recorded Investment [Line Items]
Loans	233	804
Acquired Loans | Residential mortgages | Mortgages | Pass | 1-4 family
Financing Receivable, Recorded Investment [Line Items]
Loans	281,160	294,983
Acquired Loans | Residential mortgages | Mortgages | Special mention
Financing Receivable, Recorded Investment [Line Items]
Loans	2,704	343
Acquired Loans | Residential mortgages | Mortgages | Special mention | Construction
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Acquired Loans | Residential mortgages | Mortgages | Special mention | 1-4 family
Financing Receivable, Recorded Investment [Line Items]
Loans	2,704	343
Acquired Loans | Residential mortgages | Mortgages | Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans	5,509	2,029
Acquired Loans | Residential mortgages | Mortgages | Substandard | Construction
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Acquired Loans | Residential mortgages | Mortgages | Substandard | 1-4 family
Financing Receivable, Recorded Investment [Line Items]
Loans	5,509	2,029
Acquired Loans | Consumer loans
Financing Receivable, Recorded Investment [Line Items]
Loans	229,129	186,291
Acquired Loans | Consumer loans | Home equity
Financing Receivable, Recorded Investment [Line Items]
Loans	115,227	80,279
Acquired Loans | Consumer loans | Auto and other
Financing Receivable, Recorded Investment [Line Items]
Loans	113,902	106,012
Acquired Loans | Consumer loans | Performing
Financing Receivable, Recorded Investment [Line Items]
Loans	226,772	184,879
Acquired Loans | Consumer loans | Performing | Home equity
Financing Receivable, Recorded Investment [Line Items]
Loans	113,262	79,762
Acquired Loans | Consumer loans | Performing | Auto and other
Financing Receivable, Recorded Investment [Line Items]
Loans	113,510	105,117
Acquired Loans | Consumer loans | Nonperforming
Financing Receivable, Recorded Investment [Line Items]
Loans	2,357	1,412
Acquired Loans | Consumer loans | Nonperforming | Home equity
Financing Receivable, Recorded Investment [Line Items]
Loans	1,965	517
Acquired Loans | Consumer loans | Nonperforming | Auto and other
Financing Receivable, Recorded Investment [Line Items]
Loans	$ 392	$ 895

LOAN LOSS ALLOWANCE- Summary of

LOAN LOSS ALLOWANCE- Summary of Loans Rated Special Mention or Lower (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Financing Receivable, Recorded Investment [Line Items]
Loans	$ 8,299,338	$ 6,549,787
Non-Accrual
Financing Receivable, Recorded Investment [Line Items]
Loans	22,899	22,240
Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans	110,258	95,302
Total Classified
Financing Receivable, Recorded Investment [Line Items]
Loans	133,157	117,542
Special mention
Financing Receivable, Recorded Investment [Line Items]
Loans	55,189	11,802
Total Criticized
Financing Receivable, Recorded Investment [Line Items]
Loans	188,346	129,344
Business Activities Loans
Financing Receivable, Recorded Investment [Line Items]
Loans	6,112,198	5,221,307
Business Activities Loans | Non-Accrual
Financing Receivable, Recorded Investment [Line Items]
Loans	15,659	16,816
Business Activities Loans | Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans	36,846	51,125
Business Activities Loans | Total Classified
Financing Receivable, Recorded Investment [Line Items]
Loans	52,505	67,941
Business Activities Loans | Special mention
Financing Receivable, Recorded Investment [Line Items]
Loans	28,387	7,479
Business Activities Loans | Total Criticized
Financing Receivable, Recorded Investment [Line Items]
Loans	80,892	75,420
Acquired Loans
Financing Receivable, Recorded Investment [Line Items]
Loans	2,187,140	1,328,480
Acquired Loans | Non-Accrual
Financing Receivable, Recorded Investment [Line Items]
Loans	7,240	5,424
Acquired Loans | Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans	73,412	44,177
Acquired Loans | Total Classified
Financing Receivable, Recorded Investment [Line Items]
Loans	80,652	49,601
Acquired Loans | Special mention
Financing Receivable, Recorded Investment [Line Items]
Loans	26,802	4,323
Acquired Loans | Total Criticized
Financing Receivable, Recorded Investment [Line Items]
Loans	$ 107,454	$ 53,924

PREMISES AND EQUIPMENT (Details

PREMISES AND EQUIPMENT (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Premises and equipment
Premises and equipment, gross	$ 168,775	$ 142,659
Accumulated depreciation and amortization	(59,423)	(49,444)
Premises and equipment, net	109,352	93,215
Depreciation and amortization expense	9,916	8,393	$ 8,594
Land
Premises and equipment
Premises and equipment, gross	14,177	10,563
Buildings and improvements
Premises and equipment
Premises and equipment, gross	$ 99,821	85,319
Buildings and improvements | Minimum
Premises and equipment
Estimated Useful Life	5 years
Buildings and improvements | Maximum
Premises and equipment
Estimated Useful Life	39 years
Furniture and equipment
Premises and equipment
Premises and equipment, gross	$ 49,600	42,693
Furniture and equipment | Minimum
Premises and equipment
Estimated Useful Life	3 years
Furniture and equipment | Maximum
Premises and equipment
Estimated Useful Life	7 years
Construction in process
Premises and equipment
Premises and equipment, gross	$ 5,177	$ 4,084

GOODWILL AND OTHER INTANGIBLE85

GOODWILL AND OTHER INTANGIBLES - Narrative (Details)	12 Months Ended
	Dec. 31, 2017USD ($)acquisition	Dec. 31, 2016USD ($)acquisition	Dec. 31, 2015USD ($)	Dec. 31, 2011acquisition
Finite-Lived Intangible Assets [Line Items]
Number of significant acquisitions completed (acquisition) | acquisition	1	3		2
Goodwill, impairment	$ 0	$ 0	$ 0
Amortization of intangible assets	3,493,000	2,927,000	3,563,000
Finite-lived intangible assets, amortization expense, 2018	4,900,000
Finite-lived intangible assets, amortization expense, 2019	4,700,000
Finite-lived intangible assets, amortization expense, 2020	4,400,000
Finite-lived intangible assets, amortization expense, 2021	4,200,000
Finite-lived intangible assets, amortization expense, 2022	4,100,000
Finite-lived intangible assets, amortization expense, thereafter	16,000,000
Impairment of intangible assets, finite-lived	$ 0	$ 0	$ 0
Minimum
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible asset, useful life	4 years
Maximum
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible asset, useful life	15 years

GOODWILL AND OTHER INTANGIBLE86

GOODWILL AND OTHER INTANGIBLES (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Goodwill
Balance, beginning of the period	$ 403,106	$ 323,943
Adjustments	0	(257)
Goodwill, Ending Balance	519,287	403,106
Commerce Bank
Goodwill
Goodwill acquired	116,181	0
44 Business Capital
Goodwill
Goodwill acquired	0	15,892
Ronald N. Lazzaro, PC
Goodwill
Goodwill acquired	0	5,492
First Choice Bank
Goodwill
Goodwill acquired	$ 0	$ 58,036

GOODWILL AND OTHER INTANGIBLE87

GOODWILL AND OTHER INTANGIBLES - Components of Other Intangible Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Finite-Lived Intangible Assets [Line Items]
Gross Intangible Assets	$ 82,291	$ 59,947
Accumulated Amortization	(43,995)	(40,502)
Net Intangible Assets	38,296	19,445
Non-maturity deposits (core deposit intangible)
Finite-Lived Intangible Assets [Line Items]
Gross Intangible Assets	66,923	44,523
Accumulated Amortization	(33,024)	(30,099)
Net Intangible Assets	33,899	14,424
Insurance contracts
Finite-Lived Intangible Assets [Line Items]
Gross Intangible Assets	7,558	7,558
Accumulated Amortization	(7,526)	(7,504)
Net Intangible Assets	32	54
All other intangible assets
Finite-Lived Intangible Assets [Line Items]
Gross Intangible Assets	7,810	7,866
Accumulated Amortization	(3,445)	(2,899)
Net Intangible Assets	$ 4,365	$ 4,967

OTHER ASSETS (Details)

OTHER ASSETS (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Operating Loss Carryforwards [Line Items]
Capitalized servicing rights	$ 16,361	$ 11,524	$ 5,187
Accrued interest receivable	33,739	26,113
Accrued federal and state tax receivable	33,101	19,076
Derivative assets	19,308	21,617
Assets held for sale	1,392	0
Other	13,182	20,127
Total other assets	117,083	98,457
State and Local Jurisdiction | New York
Operating Loss Carryforwards [Line Items]
Accrued federal and state tax receivable	$ 4,300	$ 5,900

OTHER ASSETS - Narrative (Detai

OTHER ASSETS - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Servicing Asset at Amortized Cost [Line Items]
Mortgage loans sold and serviced for others	$ 1,800	$ 1,300	$ 800
Servicing fees	$ 4.6	$ 3.2	$ 1.7
Weighted average discount rate (as a percent)	10.40%
Minimum
Servicing Asset at Amortized Cost [Line Items]
Pre-payment speed (as a percent)	7.78%
Maximum
Servicing Asset at Amortized Cost [Line Items]
Pre-payment speed (as a percent)	12.78%

OTHER ASSETS - Mortgage Servici

OTHER ASSETS - Mortgage Servicing Rights Activity (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Mortgage servicing rights activity
Balance at beginning of year	$ 11,524	$ 5,187
Additions	7,604	4,116
Amortization	(2,446)	(1,964)
Change in fair value	(221)	0
Allowance adjustment	(100)	0
Balance at end of year	16,361	11,524
44 Business Capital
Mortgage servicing rights activity
Additions	0	3,489
First Choice Bank
Mortgage servicing rights activity
Additions	0	696
Servicing asset at fair value	$ 3,800	$ 800

DEPOSITS (Details)

DEPOSITS (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Maturity date:
Within 1 year	$ 1,790,056	$ 1,316,973
Over 1 year to 2 years	546,381	582,764
Over 2 years to 3 years	268,897	142,160
Over 3 years to 4 years	161,314	150,388
Over 4 years to 5 years	121,400	137,845
Over 5 years	2,157	3,413
Total	2,890,205	2,333,543
Less than $100,000	733,785	656,055
$100,000 or more	$ 2,156,420	$ 1,677,488

DEPOSITS - Narrative (Details)

DEPOSITS - Narrative (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Related Party Transaction [Line Items]
Brokered deposits	$ 1,200,000	$ 900,000
Reciprocal deposits	99,800	113,400
Time deposits	2,890,205	2,333,543
Affiliated Entity
Related Party Transaction [Line Items]
Time deposits	$ 36,000	$ 17,200

BORROWED FUNDS (Details)

BORROWED FUNDS (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Borrowings and junior subordinated debentures
Short-term borrowings	$ 667,300	$ 1,082,044
Long-term borrowings	469,775	231,953
Total borrowings	$ 1,137,075	$ 1,313,997
Weighted average rate on short-term borrowings (percent)	1.48%	0.72%
Weighted average rate on long-term borrowings (percent)	2.46%	3.35%
Weighted average interest rate (percent)	1.88%	1.19%
Advances from the FHLBB
Borrowings and junior subordinated debentures
Short-term borrowings	$ 667,300	$ 1,072,044
Long-term borrowings	$ 380,436	$ 142,792
Weighted average rate on short-term borrowings (percent)	1.48%	0.71%
Weighted average rate on long-term borrowings (percent)	1.54%	1.53%
Other Borrowings
Borrowings and junior subordinated debentures
Short-term borrowings	$ 0	$ 10,000
Weighted average rate on short-term borrowings (percent)	0.00%	2.42%
Subordinated notes
Borrowings and junior subordinated debentures
Long-term borrowings	$ 73,875	$ 73,697
Weighted average rate on long-term borrowings (percent)	7.00%	7.00%
Junior subordinated notes
Borrowings and junior subordinated debentures
Long-term borrowings	$ 15,464	$ 15,464
Weighted average rate on long-term borrowings (percent)	3.30%	2.77%

BORROWED FUNDS - Narrative (Det

BORROWED FUNDS - Narrative (Details) - USD ($)	1 Months Ended	12 Months Ended
	Sep. 30, 2012	Dec. 31, 2017	Dec. 31, 2016
Borrowings and junior subordinated debentures
Line of credit		$ 3,000,000
Short-term borrowings		667,300,000	$ 1,082,044,000
Long-term borrowings		469,775,000	231,953,000
Variable-rate FHLB advances		0
Advances from the FHLBB
Borrowings and junior subordinated debentures
Outstanding balance, line of credit		0	0
Short-term borrowings		667,300,000	1,072,044,000
Long-term borrowings		380,436,000	142,792,000
Federal Reserve Bank Advances
Borrowings and junior subordinated debentures
Short-term borrowings		0	0
Federal Home Loan Bank Certificates And Obligations F H L B Callable Advances
Borrowings and junior subordinated debentures
Long-term borrowings			11,000,000
Federal Home Loan Bank Certificates And Obligations F H L B Amortizing Advances
Borrowings and junior subordinated debentures
Long-term borrowings		1,400,000	1,200,000
Subordinated notes
Borrowings and junior subordinated debentures
Long-term borrowings		73,875,000	73,697,000
Maturity period	15 years
Principal amount of debt issued	$ 75,000,000
Discount rate (percent)	1.15%
Fixed interest rate (percent)	6.875%
Maturity period with fixed interest rate	10 years
Subordinated notes | Three-month LIBOR rate
Borrowings and junior subordinated debentures
Interest rate margin (percent)	5.113%
Unamortized debt issuance costs		583,000	706,000
Junior subordinated notes
Borrowings and junior subordinated debentures
Long-term borrowings		$ 15,464,000	$ 15,464,000
Junior subordinated notes | Trust I
Borrowings and junior subordinated debentures
Common stock of trust (percent)		100.00%
Common stock of trust included in other asset		$ 500,000
Sole asset of trust in form of debt		$ 15,500,000
Variable interest rate (percent)		3.30%	2.77%
Period up to which interest payments can be deferred		5 years
Junior subordinated notes | LIBOR | Trust I
Borrowings and junior subordinated debentures
Interest rate margin (percent)		1.85%

BORROWED FUNDS - Summary of Mat

BORROWED FUNDS - Summary of Maturities of FHLBB Advances (Details) $ in Thousands	Dec. 31, 2017USD ($)
Principal
Total FHLBB advances	$ 1,047,736
Fixed rate advances
Principal
2,018	836,115
2,019	150,082
2,020	54,101
2,021	220
2022 and beyond	7,218
Total FHLBB advances	$ 1,047,736
Weighted Average
Weighted Average Rate (percent)
Total FHLBB advances (percent)	1.50%
Weighted Average | Fixed rate advances
Weighted Average Rate (percent)
2018 (percent)	1.43%
2019 (percent)	1.64%
2020 (percent)	2.04%
2021 (percent)	3.21%
2022 and beyond (percent)	2.64%
Total FHLBB advances (percent)	1.50%

OTHER LIABILITIES (Details)

OTHER LIABILITIES (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Other Liabilities Disclosure [Abstract]
Derivative liabilities	$ 15,838	$ 24,420
Capital lease obligation	11,323	11,639
Asset purchase settlement payable	70,637	29,158
Employee benefits liability	27,093	17,972
Level lease liability	5,766	6,997
Accrued interest payable	6,813	4,394
Customer transaction clearing accounts	9,118	1,786
Other	41,294	36,789
Total other liabilities	$ 187,882	$ 133,155

EMPLOYEE BENEFIT PLANS EMPLOYEE

EMPLOYEE BENEFIT PLANS EMPLOYEE BENEFIT PLANS - Narrative (Details)	Aug. 01, 2014USD ($)	Dec. 31, 2017USD ($)acquisitionemployee	Dec. 31, 2016USD ($)acquisition	Dec. 31, 2015USD ($)	Dec. 31, 2011acquisition	Oct. 31, 2017USD ($)	Apr. 30, 2015USD ($)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Expense under the plan		$ 3,400,000	$ 3,900,000	$ 3,600,000
Number of significant acquisitions completed (acquisition) | acquisition		1	3		2
Hampden Bancorp Inc
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Split-dollar agreement, accrued liability		$ 1,200,000	$ 1,200,000				$ 860,000
Commerce Bank
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Split-dollar agreement, accrued liability		$ 2,800,000				$ 2,700,000
Fixed Income Funds
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Target plan asset allocation (percent)		34.00%
Marketable equity securities
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Target plan asset allocation (percent)		65.00%
Cash and Cash Equivalents
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Target plan asset allocation (percent)		1.00%
Pension Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Number of employees participation (employee) | employee		0
Net actuarial (gain) loss		$ 1,300,000	1,500,000
Expected cash contributions by employer		0
Amount expected to be amortized from other comprehensive income into net periodic pension cost over the next fiscal year		83,000
Defined benefit plan, fair value of plan assets		5,446,000	5,121,000	5,211,000
Transfers between Level 1, 2, and 3		$ 0	$ 0
Discount rate (percent)		3.98%	4.17%
Pension Plans | Level 3
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, fair value of plan assets		$ 0	$ 0
Pension Plans | Fixed Income Funds
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, fair value of plan assets		1,308,000	1,378,000
Postretirement Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Net actuarial (gain) loss		199,000	(126,000)
Amount expected to be amortized from other comprehensive income into net periodic pension cost over the next fiscal year		83,000
Defined benefit plan, fair value of plan assets		$ 0	$ 0	0
Prior service cost of long-term care plan participants	$ 558,000
Discount rate (percent)		3.44%	3.91%
Assumed health care cost trend rate (percent)		7.75%
Assumed health care cost trend rate in 2020 (percent)		3.89%
Supplemental Employee Retirement Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Eligible age for retirement plan		62 years
Accrued liability for other plans		$ 8,300,000	$ 7,400,000
Other plans expense		968,000	917,000	$ 752,000
Supplemental Employee Retirement Plan | Hampden Bancorp Inc
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Accrued liability for other plans		$ 1,100,000	$ 1,200,000				$ 1,400,000

EMPLOYEE BENEFIT PLANS (Details

EMPLOYEE BENEFIT PLANS (Details) - USD ($) $ in Thousands	Aug. 01, 2014	Dec. 31, 2017	Dec. 31, 2016
Pension Plans
Change in projected benefit obligation:
Projected benefit obligation at beginning of year		$ 6,126	$ 6,585
Service Cost		66	76
Interest cost		237	267
Actuarial loss (gain)		309	(308)
Benefits paid		(324)	(318)
Settlements		(61)	(176)
Projected benefit obligation at end of year		6,353	6,126
Accumulated benefit obligation		6,353	6,126
Change in fair value of plan assets:
Fair value of plan assets at plan beginning of year		5,121	5,211
Actual return on plan assets		710	404
Benefits paid		(324)	(318)
Settlements		(61)	(176)
Fair value of plan assets at end of year		5,446	5,121
Funded status of the plan
Underfunded status		907	1,005
Postretirement Benefits
Change in projected benefit obligation:
Projected benefit obligation at beginning of year		3,249	3,039
Prior service cost of long-term care plan participants	$ 558
Service Cost		35	32
Interest cost		131	129
Participant contributions		46	47
Actuarial loss (gain)		326	130
Benefits paid		(94)	(128)
Projected benefit obligation at end of year		3,693	3,249
Change in fair value of plan assets:
Fair value of plan assets at plan beginning of year		0	0
Benefits paid		(94)	(128)
Contributions by employer		48	81
Contributions by participant		46	47
Fair value of plan assets at end of year		$ 0	$ 0

EMPLOYEE BENEFIT PLANS - Amoun

EMPLOYEE BENEFIT PLANS - Amounts Recognized in Consolidated Balance Sheet (Details) - Other Liabilities - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Pension Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plans, liabilities	$ 907	$ 1,005
Postretirement Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plans, liabilities	$ 3,693	$ 3,249

EMPLOYEE BENEFIT PLANS - Net Pe

EMPLOYEE BENEFIT PLANS - Net Periodic Pension Cost (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Pension Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service Cost	$ 66	$ 76
Interest cost	237	267
Expected return on plan assets	(346)	(361)
Amortization of unrecognized actuarial loss	100	163
Net periodic pension costs	57	145
Postretirement Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service Cost	35	32
Interest cost	131	129
Amortization of unrecognized actuarial loss	0	0
Amortization of net prior service credit	83	83
Net periodic pension costs	$ 249	$ 244

EMPLOYEE BENEFIT PLANS - Change

EMPLOYEE BENEFIT PLANS - Change in Plan Assets and Benefit Obligations Recognized (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Pension Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Amortization of actuarial (loss)	$ (100)	$ (163)
Actuarial (gain) loss	(54)	(351)
Total recognized in accumulated other comprehensive income	(154)	(514)
Total recognized in net periodic pension cost recognized and other comprehensive income	(97)	(369)
Postretirement Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Amortization of actuarial (loss)	0	0
Actuarial (gain) loss	199	(126)
Amortization of prior service credit	(83)	(83)
Total recognized in accumulated other comprehensive income	116	(209)
Accrued post-retirement liability recognized	$ 1,918	$ 1,718

EMPLOYEE BENEFIT PLANS - Princi

EMPLOYEE BENEFIT PLANS - Principal Actuarial Assumptions(Details) - Pension Plans	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Projected benefit obligation, discount rate	3.51%	3.98%
Net periodic pension cost, discount rate	3.98%	4.17%
Net periodic pension cost, long term rate of return on plan assets	7.00%	7.00%

EMPLOYEE BENEFIT PLANS - Fair V

EMPLOYEE BENEFIT PLANS - Fair Values of the Plan's Assets by Category and Level (Details 6) - Pension Plans - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, fair value of plan assets	$ 5,446	$ 5,121	$ 5,211
Equity Mutual Funds | Large-Cap
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, fair value of plan assets	1,820	1,624
Equity Mutual Funds | Mid-Cap
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, fair value of plan assets	439	401
Equity Mutual Funds | Small-Cap
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, fair value of plan assets	438	415
Equity Mutual Funds | International
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, fair value of plan assets	893	757
Fixed Income Funds
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, fair value of plan assets	1,308	1,378
Intermediate Duration
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, fair value of plan assets	437	472
Cash Equivalents - money market
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, fair value of plan assets	111	74
Level 1
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, fair value of plan assets	29	30
Level 1 | Equity Mutual Funds | Large-Cap
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, fair value of plan assets	0	0
Level 1 | Equity Mutual Funds | Mid-Cap
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, fair value of plan assets	0	0
Level 1 | Equity Mutual Funds | Small-Cap
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, fair value of plan assets	0	0
Level 1 | Equity Mutual Funds | International
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, fair value of plan assets	0	0
Level 1 | Fixed Income Funds
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, fair value of plan assets	0	0
Level 1 | Intermediate Duration
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, fair value of plan assets	0	0
Level 1 | Cash Equivalents - money market
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, fair value of plan assets	29	30
Level 2
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, fair value of plan assets	5,417	5,091
Level 2 | Equity Mutual Funds | Large-Cap
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, fair value of plan assets	1,820	1,624
Level 2 | Equity Mutual Funds | Mid-Cap
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, fair value of plan assets	439	401
Level 2 | Equity Mutual Funds | Small-Cap
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, fair value of plan assets	438	415
Level 2 | Equity Mutual Funds | International
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, fair value of plan assets	893	757
Level 2 | Fixed Income Funds
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, fair value of plan assets	1,308	1,378
Level 2 | Intermediate Duration
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, fair value of plan assets	437	472
Level 2 | Cash Equivalents - money market
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, fair value of plan assets	$ 82	$ 44

EMPLOYEE BENEFIT PLANS - Estima

EMPLOYEE BENEFIT PLANS - Estimated Benefit Payments (Details) $ in Thousands	Dec. 31, 2017USD ($)
Pension Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
2,018	$ 343
2,019	380
2,020	372
2,021	361
2,022	386
2023 - 2027	1,792
Postretirement Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
2,018	103
2,019	103
2,020	102
2,021	106
2,022	109
2023 - 2027	$ 548

EMPLOYEE BENEFIT PLANS - Post-r

EMPLOYEE BENEFIT PLANS - Post-retirement Plan (Details) - Postretirement Benefits - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Net prior service cost (credit)	$ 1,576	$ 1,659
Net actuarial (gain) loss	199	(126)
Total recognized in accumulated other comprehensive income	$ 1,775	$ 1,533

INCOME TAXES - Provision for In

INCOME TAXES - Provision for Income Taxes (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 tax expense									$ 11,686	$ 6,758	$ 4,696
State tax expense									1,112	1,101	(1,631)
Total current expense									12,798	7,859	3,065
Deferred:
Federal tax expense									29,824	9,438	2,023
State tax expense									1,805	1,591	(24)
Total deferred tax expense (1)									31,629	11,029	1,999
Change in valuation allowance									75	(104)	0
Income tax expense	$ 22,292	$ 7,211	$ 8,237	$ 6,762	$ 362	$ 6,953	$ 5,249	$ 6,220	$ 44,502	$ 18,784	$ 5,064

INCOME TAXES - Narrative (Detai

INCOME TAXES - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Contingency [Line Items]
Deferred tax expense	$ 31,629	$ 11,029	$ 1,999
Write down of net deferred tax asset	18,100
Decrease in net deferred tax assets	5,900
Deferred tax benefit recognized due to decrease in goodwill	34,500
Deferred tax benefit recognized due to increase in equity	3,100
Increase in valuation allowance	75
State tax basis, net of Federal tax benefit (of 35%)	200	$ 125
Net operating loss carryforwards	1,400
Alternative minimum tax credit carryforward amount	4,000
Internal Revenue Service (IRS)
Income Tax Contingency [Line Items]
Operating loss carryforwards	6,500
State and Local Jurisdiction | New York
Income Tax Contingency [Line Items]
Operating loss carryforwards	3,300
State and Local Jurisdiction | Connecticut
Income Tax Contingency [Line Items]
Operating loss carryforwards	$ 13,900

INCOME TAXES - Effective Tax Ra

INCOME TAXES - Effective 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
Effective Income Tax Rate Reconciliation, Amount [Abstract]
Statutory tax rate									$ 34,912	$ 27,108	$ 19,104
State taxes, net of federal tax benefit									2,232	1,675	(974)
Tax exempt income - investments, net									(5,395)	(3,849)	(3,463)
Bank-owned life insurance									(1,556)	(1,364)	(1,284)
Non-deductible merger costs									368	542	422
Non-deductible goodwill on disposal operations sale									0	0	313
Tax credits, net of basis reduction									(4,656)	(6,225)	(8,308)
Change in valuation allowance									75	125	0
Impact of federal tax reform enactment									18,145	0	0
Other, net									377	772	(746)
Income tax expense	$ 22,292	$ 7,211	$ 8,237	$ 6,762	$ 362	$ 6,953	$ 5,249	$ 6,220	$ 44,502	$ 18,784	$ 5,064
Effective Income Tax Rate Reconciliation, Percent [Abstract]
Statutory tax rate (percent)									35.00%	35.00%	35.00%
State taxes, net of federal tax benefit (percent)									2.20%	2.20%	(1.80%)
Tax exempt income - investments, net (percent)									(5.40%)	(5.00%)	(6.30%)
Bank-owned life insurance (percent)									(1.60%)	(1.80%)	(2.40%)
Non-deductible merger costs (percent)									0.40%	0.70%	0.80%
Non-deductible goodwill on disposal operations sale (percent)									0.00%	0.00%	0.60%
Tax credits, net of basis reduction (percent)									(4.70%)	(8.00%)	(15.20%)
Change in valuation allowance (percent)									0.10%	0.20%	0.00%
Impact of federal tax reform enactment (percent)									18.20%	0.00%	0.00%
Other, net (percent)									0.40%	1.00%	(1.40%)
Effective tax rate (percent)									44.60%	24.30%	9.30%

INCOME TAXES - Deferred Tax Lia

INCOME TAXES - Deferred Tax Liabilities and Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Deferred tax assets:
Allowance for loan losses	$ 14,578	$ 17,747
Tax credit carryforwards	4,100	4,100
Unrealized capital loss on tax credit investments	6,502	6,999
Employee benefit plans	4,983	7,813
Purchase accounting adjustments	37,843	23,520
Net operating loss carryforwards	1,374	2,643
Other	2,332	4,997
Deferred tax assets, net before valuation allowances	71,712	67,819
Valuation allowance	(200)	(125)
Deferred tax assets, net of valuation allowances	71,512	67,694
Deferred tax liabilities:
Net unrealized gain on swaps, securities available for sale, and pension in OCI	(1,888)	(5,884)
Premises and equipment	(1,126)	(2,519)
Loan servicing rights	(2,174)	(4,546)
Deferred loan fees	(3,900)	0
Intangible amortization	(15,001)	(11,543)
Other	(362)	(2,074)
Deferred tax liabilities	(24,451)	(26,566)
Deferred tax assets, net	$ 47,061	$ 41,128

INCOME TAXES - Valuation Allowa

INCOME TAXES - Valuation Allowance (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
State tax basis difference, net of Federal tax benefit	$ (200)	$ (125)
Valuation allowances	$ 200	$ 125
Federal tax rate (percent)	35.00%	35.00%	35.00%

INCOME TAXES - Unrecognized Tax

INCOME TAXES - Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Unrecognized tax benefits at January 1	$ 460	$ 307	$ 553
Increase in gross amounts of tax positions related to prior years	0	270	0
Decrease in gross amounts of tax positions related to prior years	(156)	0	0
Decrease due to settlement with taxing authority	0	0	0
Increase in gross amounts of tax positions related to current year	0	0	0
Decrease due to lapse in statute of limitations	0	(117)	(246)
Unrecognized tax benefits at December 31	$ 304	$ 460	$ 307

DERIVATIVE INSTRUMENTS AND H112

DERIVATIVE INSTRUMENTS AND HEDGING ACTIVITIES - Narrative (Details) $ in Thousands	Feb. 07, 2017USD ($)	Dec. 31, 2017USD ($)	Sep. 30, 2017USD ($)	Jun. 30, 2017USD ($)	Mar. 31, 2017USD ($)contract	Dec. 31, 2016USD ($)	Sep. 30, 2016USD ($)	Jun. 30, 2016USD ($)	Mar. 31, 2016USD ($)	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)
Derivative [Line Items]
Derivative, notional amount		$ 2,510,937				$ 2,199,862				$ 2,510,937	$ 2,199,862
Cash pledged as collateral to derivative counterparties		2,100				900				2,100	900
Amortized cost of securities pledged as collateral to derivative counterparties		24,400				47,800				24,400	47,800
Fair value of securities as pledged collateral to derivative counterparties		24,400				47,900				24,400	47,900
Interest expense		19,457	$ 17,062	$ 15,121	$ 13,823	13,276	$ 12,540	$ 11,577	$ 10,779	65,463	48,172	$ 33,181
Reclassification out of Accumulated Other Comprehensive Income | Accumulated Net Gain (Loss) from Cash Flow Hedges
Derivative [Line Items]
Interest expense	$ 6,600
Interest Rate Swap
Derivative [Line Items]
Cash pledged as collateral to derivative counterparties		1,960				650				1,960	650
Amount of collateral posted for the net liability positions		5,900				19,800				5,900	19,800
Interest Rate Swap | Commercial counterparties
Derivative [Line Items]
Cash pledged as collateral to derivative counterparties		0				0				0	0
Derivative asset, fair value, amount offset against collateral		8,600				11,500				8,600	11,500
Amount of collateral posted for the net liability positions		5,400				4,400				5,400	4,400
Interest Rate Swap | Financial institutions counterparties
Derivative [Line Items]
Derivative asset, fair value, amount offset against collateral		1,100				49				1,100	49
Amount of collateral posted for the net liability positions		5,900				15,400				5,900	15,400
Non-hedging derivatives
Derivative [Line Items]
Derivative, notional amount		193,966				208,145				193,966	208,145
Cash Flow Hedging
Derivative [Line Items]
Durations of derivative instruments					3 years
Cash Flow Hedging | Interest Rate Swap
Derivative [Line Items]
Number of derivative contracts (contract) | contract					6
Cash Flow Hedging | Interest Rate Swap | FHLBB borrowings
Derivative [Line Items]
Derivative, notional amount	$ 300,000				$ 300,000
Interest expense										393	3,981	$ 0
Cash Flow Hedging | Hedging derivatives
Derivative [Line Items]
Derivative, notional amount		0				300,000				0	300,000
Cash Flow Hedging | Hedging derivatives | Interest Rate Swap | FHLBB borrowings
Derivative [Line Items]
Derivative, notional amount		0								0
Economic Hedging
Derivative [Line Items]
Credit valuation adjustments		$ (316)								$ (316)
Economic Hedging | Tax advantaged economic development bonds
Derivative [Line Items]
Fixed rate of interest (percent)		5.09%								5.09%
Maturity period										21 years
Economic Hedging | Interest Rate Swap | Tax advantaged economic development bonds
Derivative [Line Items]
Derivative, notional amount		$ 10,800								$ 10,800
Economic Hedging | Hedging derivatives
Derivative [Line Items]
Derivative, notional amount		2,316,971				1,691,717				2,316,971	1,691,717
Economic Hedging | Hedging derivatives | Interest Rate Swap
Derivative [Line Items]
Derivative, notional amount		1,900,000								1,900,000
Economic Hedging | Hedging derivatives | Interest Rate Swap | Tax advantaged economic development bonds
Derivative [Line Items]
Derivative, notional amount		10,755				11,386				10,755	11,386
Economic Hedging | Hedging derivatives | Risk Participation Agreements
Derivative [Line Items]
Derivative, notional amount		142,054				83,360				142,054	83,360
Economic Hedging | Hedging derivatives | Forward Commitments
Derivative [Line Items]
Derivative, notional amount		$ 276,572				$ 259,889				$ 276,572	$ 259,889

DERIVATIVE INSTRUMENTS AND H113

DERIVATIVE INSTRUMENTS AND HEDGING ACTIVITIES (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Mar. 31, 2017	Feb. 07, 2017
Offsetting Assets [Line Items]
Notional Amount	$ 2,510,937	$ 2,199,862
Estimated Fair Value Asset (Liability)	3,470	(2,804)
Cash flow hedges | Interest rate swap | FHLBB borrowings
Offsetting Assets [Line Items]
Notional Amount			$ 300,000	$ 300,000
Economic hedges | Interest rate swap | Tax advantaged economic development bonds
Offsetting Assets [Line Items]
Notional Amount	10,800
Hedging derivatives | Cash flow hedges
Offsetting Assets [Line Items]
Notional Amount	0	300,000
Estimated Fair Value Asset (Liability)	0	(6,573)
Hedging derivatives | Cash flow hedges | Interest rate swap | FHLBB borrowings
Offsetting Assets [Line Items]
Notional Amount	$ 0
Weighted Average Maturity	0 years
Derivative, weighted average rate, received (percent)	0.00%
Derivative, weighted average rate, paid (percent)	0.00%
Estimated Fair Value Asset (Liability)	$ 0
Hedging derivatives | Cash flow hedges | Forward starting interest rate swap | FHLBB borrowings
Offsetting Assets [Line Items]
Notional Amount		$ 300,000
Weighted Average Maturity		2 years 3 months 18 days
Derivative, weighted average rate, received (percent)		0.63%
Derivative, weighted average rate, paid (percent)		2.29%
Estimated Fair Value Asset (Liability)		$ (6,573)
Hedging derivatives | Economic hedges
Offsetting Assets [Line Items]
Notional Amount	2,316,971	1,691,717
Estimated Fair Value Asset (Liability)	(1,789)	(969)
Hedging derivatives | Economic hedges | Interest rate swap
Offsetting Assets [Line Items]
Notional Amount	1,900,000
Hedging derivatives | Economic hedges | Interest rate swap | Tax advantaged economic development bonds
Offsetting Assets [Line Items]
Notional Amount	$ 10,755	$ 11,386
Weighted Average Maturity	11 years 10 months 24 days	12 years 10 months 24 days
Derivative, weighted average rate, received (percent)	1.73%	0.98%
Derivative, weighted average rate, paid (percent)	5.09%	5.09%
Estimated Fair Value Asset (Liability)	$ (1,649)	$ (2,021)
Hedging derivatives | Economic hedges | Interest rate swap | Commercial loan
Offsetting Assets [Line Items]
Notional Amount	$ 943,795	$ 668,541
Weighted Average Maturity	5 years 10 months 24 days	6 years 2 months 12 days
Derivative, weighted average rate, received (percent)	3.26%	2.43%
Derivative, weighted average rate, paid (percent)	4.25%	4.21%
Estimated Fair Value Asset (Liability)	$ (3,195)	$ (6,752)
Hedging derivatives | Economic hedges | Reverse interest rate swaps | Commercial loan
Offsetting Assets [Line Items]
Notional Amount	$ 943,795	$ 668,541
Weighted Average Maturity	5 years 10 months 24 days	6 years 2 months 12 days
Derivative, weighted average rate, received (percent)	4.25%	4.21%
Derivative, weighted average rate, paid (percent)	3.26%	2.43%
Estimated Fair Value Asset (Liability)	$ 3,204	$ 7,077
Hedging derivatives | Economic hedges | Risk participation agreements
Offsetting Assets [Line Items]
Notional Amount	$ 142,054	$ 83,360
Weighted Average Maturity	8 years 4 months 24 days	11 years 7 months 6 days
Estimated Fair Value Asset (Liability)	$ (26)	$ 5
Hedging derivatives | Economic hedges | Forward sale commitments
Offsetting Assets [Line Items]
Notional Amount	$ 276,572	$ 259,889
Weighted Average Maturity	2 months 12 days	2 months 12 days
Estimated Fair Value Asset (Liability)	$ (123)	$ 722
Non-hedging derivatives
Offsetting Assets [Line Items]
Notional Amount	193,966	208,145
Estimated Fair Value Asset (Liability)	5,259	4,738
Non-hedging derivatives | Commitments to lend
Offsetting Assets [Line Items]
Notional Amount	$ 193,966	$ 208,145
Weighted Average Maturity	2 months 12 days	2 months 12 days
Estimated Fair Value Asset (Liability)	$ 5,259	$ 4,738

DERIVATIVE INSTRUMENTS AND H114

DERIVATIVE INSTRUMENTS AND HEDGING ACTIVITIES - Amounts included in Consolidated Statements of Income and in Other Comprehensive Income (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
Derivative [Line Items]
Less: Reclassification of unrealized (loss) from accumulated other comprehensive loss to interest expense	$ (19,457)	$ (17,062)	$ (15,121)	$ (13,823)	$ (13,276)	$ (12,540)	$ (11,577)	$ (10,779)	$ (65,463)	$ (48,172)	$ (33,181)
Interest Rate Swap | Cash Flow Hedging
Derivative [Line Items]
Other comprehensive income recorded in accumulated other comprehensive income, net of reclassification adjustments and tax effects									3,984	1,123	(3,138)
FHLBB borrowings | Interest Rate Swap | Cash Flow Hedging
Derivative [Line Items]
Unrealized (loss) recognized in accumulated other comprehensive loss									(449)	(2,023)	(5,232)
Less: Reclassification of unrealized (loss) from accumulated other comprehensive loss to interest expense									(393)	(3,981)	0
Net tax effect on items recognized in accumulated other comprehensive income									(2,589)	(835)	2,094
Other Non-interest Expense | FHLBB borrowings | Interest Rate Swap | Cash Flow Hedging
Derivative [Line Items]
Less: reclassification of unrealized (loss) from accumulated other comprehensive income to other non-interest expense									$ (6,629)	$ 0	$ 0

DERIVATIVE INSTRUMENTS AND H115

DERIVATIVE INSTRUMENTS AND HEDGING ACTIVITIES - Economic Hedges and Non-hedging Derivatives (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Hedging derivatives | Economic Hedging | Interest Rate Swap | Industrial Revenue Bond
Derivative [Line Items]
Unrealized gain (loss) recognized in other non-interest income	$ 371	$ (75)	$ (344)
Hedging derivatives | Economic Hedging | Interest Rate Swap | Commercial loan
Derivative [Line Items]
Unrealized gain (loss) recognized in other non-interest income	3,557	1,312	(4,852)
Hedging derivatives | Economic Hedging | Reverse Interest Rate Swaps | Commercial loan
Derivative [Line Items]
Unrealized gain (loss) recognized in other non-interest income	(3,557)	(1,312)	4,852
(Unfavorable) Favorable change in credit valuation adjustment recognized in other non-interest income	(316)	338	(51)
Hedging derivatives | Economic Hedging | Risk Participation Agreements
Derivative [Line Items]
Unrealized gain (loss) recognized in other non-interest income	(31)	(61)	(36)
Hedging derivatives | Economic Hedging | Forward Commitments
Derivative [Line Items]
Unrealized gain (loss) recognized in other non-interest income	(123)	(1,176)	(247)
Realized gain (loss) in other non-interest income	(1,764)	(3,705)	45
Non-hedging derivatives | Commitments to lend
Derivative [Line Items]
Unrealized gain (loss) recognized in other non-interest income	5,259	8,373	2,436
Realized gain (loss) in other non-interest income	$ 50,879	$ 3,650	$ 1,899

DERIVATIVE INSTRUMENTS AND H116

DERIVATIVE INSTRUMENTS AND HEDGING ACTIVITIES - Offsetting of Financial Assets and Derivative Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Offsetting Assets [Line Items]
Net Amounts of Assets Presented in the Statements of Condition	$ 19,308	$ 21,617
Interest Rate Swap
Offsetting Assets [Line Items]
Gross Amounts of Recognized Assets	11,269	11,510
Gross Amounts Offset in the Statements of Condition	(1,622)	0
Net Amounts of Assets Presented in the Statements of Condition	9,647	11,510
Gross amounts not offset in the Statement of Condition, financial instruments	0	0
Gross amounts not offset in the Statement of Condition, cash collateral received	0	0
Net Amount	9,647	11,510
Interest Rate Swap | Institutional counterparties
Offsetting Assets [Line Items]
Gross Amounts of Recognized Assets	2,692	49
Gross Amounts Offset in the Statements of Condition	(1,622)	0
Net Amounts of Assets Presented in the Statements of Condition	1,070	49
Gross amounts not offset in the Statement of Condition, financial instruments	0	0
Gross amounts not offset in the Statement of Condition, cash collateral received	0	0
Net Amount	1,070	49
Interest Rate Swap | Commercial counterparties
Offsetting Assets [Line Items]
Gross Amounts of Recognized Assets	8,577	11,461
Gross Amounts Offset in the Statements of Condition	0	0
Net Amounts of Assets Presented in the Statements of Condition	8,577	11,461
Gross amounts not offset in the Statement of Condition, financial instruments	0	0
Gross amounts not offset in the Statement of Condition, cash collateral received	0	0
Net Amount	$ 8,577	$ 11,461

DERIVATIVE INSTRUMENTS AND H117

DERIVATIVE INSTRUMENTS AND HEDGING ACTIVITIES - Offsetting of Financial Liabilities and Derivative Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Offsetting Liabilities [Line Items]
Net Amounts of Liabilities Presented in the Statement of Condition	$ (15,838)	$ (24,420)
Gross amounts not offset in the Statements of Condition, cash collateral pledged	2,100	900
Interest Rate Swap
Offsetting Liabilities [Line Items]
Gross Amounts of Recognized Liabilities	(14,152)	(24,484)
Gross Amounts Offset in the Statements of Condition	2,837	4,712
Net Amounts of Liabilities Presented in the Statement of Condition	(11,315)	(19,772)
Gross amounts not offset in the Statements of Condition, financial instruments	3,982	14,738
Gross amounts not offset in the Statements of Condition, cash collateral pledged	1,960	650
Net Amount	(5,373)	(4,384)
Interest Rate Swap | Institutional counterparties
Offsetting Liabilities [Line Items]
Gross Amounts of Recognized Liabilities	(8,777)	(20,077)
Gross Amounts Offset in the Statements of Condition	2,835	4,689
Net Amounts of Liabilities Presented in the Statement of Condition	(5,942)	(15,388)
Gross amounts not offset in the Statements of Condition, financial instruments	3,982	14,738
Gross amounts not offset in the Statements of Condition, cash collateral pledged	1,960	650
Net Amount	0	0
Interest Rate Swap | Commercial counterparties
Offsetting Liabilities [Line Items]
Gross Amounts of Recognized Liabilities	(5,375)	(4,407)
Gross Amounts Offset in the Statements of Condition	2	23
Net Amounts of Liabilities Presented in the Statement of Condition	(5,373)	(4,384)
Gross amounts not offset in the Statements of Condition, financial instruments	0	0
Gross amounts not offset in the Statements of Condition, cash collateral pledged	0	0
Net Amount	$ (5,373)	$ (4,384)

OTHER COMMITMENTS, CONTINGEN118

OTHER COMMITMENTS, CONTINGENCIES, AND OFF-BALANCE SHEET ACTIVITIES) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Financial commitments whose contractual amount represents credit risk
Total	$ 1,605,594	$ 1,446,396
Commitments to originate new loans
Financial commitments whose contractual amount represents credit risk
Total	244,252	243,519
Unused funds on commercial and other lines of credit
Financial commitments whose contractual amount represents credit risk
Total	678,567	574,043
Unadvanced funds on home equity lines of credit
Financial commitments whose contractual amount represents credit risk
Total	297,367	281,621
Unadvanced funds on construction and real estate loans
Financial commitments whose contractual amount represents credit risk
Total	360,472	320,635
Standby letters of credit
Financial commitments whose contractual amount represents credit risk
Total	13,613	14,939
Lease obligation
Financial commitments whose contractual amount represents credit risk
Total	$ 11,323	$ 11,639

OTHER COMMITMENTS, CONTINGEN119

OTHER COMMITMENTS, CONTINGENCIES, AND OFF-BALANCE SHEET ACTIVITIES - Narrative (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2017USD ($)employee	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)
Future minimum rental payments
2,018	$ 12,800
2,019	10,800
2,020	9,300
2,021	8,300
2,022	7,600
Thereafter	$ 47,600
Extendable term	20 years
Total rent expense	$ 12,000	$ 8,300	$ 7,500
Lease Obligations
2,018	647
2,019	646
2,020	644
2,021	612
2,022	583
Thereafter	5,000
Future obligations required under the financing lease
2,018	86
2,019	86
2,020	86
2,021	86
2,022	87
Thereafter	$ 1,500
Employment agreement term	3 years
Number of senior executives which entered into an employment agreement with the Company | employee	1

SHAREHOLDERS' EQUITY AND EAR120

SHAREHOLDERS' EQUITY AND EARNINGS PER COMMON SHARE SHAREHOLDERS' EQUITY AND EARNINGS PER COMMON SHARE (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Capital [Abstract]
Total capital to risk-weighted assets, actual amount	$ 1,063,843	$ 803,618
Total capital to risk-weighted assets, actual percent	12.43%	11.87%
Total capital to risk-weighted assets, minimum capital requirement, amount	$ 684,692	$ 541,603
Total capital to risk-weighted assets, minimum capital requirement, percent	8.00%	8.00%
Total capital to risk-weighted assets, minimum to be well capitalized under prompt corrective action provisions, amount	$ 855,865	$ 677,004
Common Equity Tier One Risk Based Capital to Risk Weighted Assets, Amount	$ 942,389	$ 670,120
Common Equity Tier One Risk Based Capital to Risk Weighted Assets	11.01%	9.90%
Common Equity Tier One Risk Based Capital Required to be Well Capitalized to Risk Weighted Assets, Amount	$ 385,139	$ 304,652
Common Equity Tier One Risk Based Capital Required to be Well Capitalized to Risk Weighted Assets	4.50%	4.50%
Common Entity Tier 1 Capital To Risk Weighted Assets, Capital Required to be Well Capitalized	$ 556,312	$ 440,053
Tier One Risk Based Capital [Abstract]
Tier 1 capital risk-weighted assets, amount	$ 954,103	$ 681,500
Tier 1 capital risk-weighted assets, percent	11.15%	10.07%
Tier 1 capital risk-weighted assets, minimum capital requirement, amount	$ 513,519	$ 406,202
Tier 1 capital risk-weighted assets, minimum capital requirement, percent	6.00%	6.00%
Tier 1 capital risk-weighted assets, minimum to be well capitalized under prompt corrective action provisions, amount	$ 684,692	$ 541,603
Tier One Leverage Capital [Abstract]
Tier 1 capital to average assets, amount	$ 954,103	$ 681,500
Tier 1 capital to average assets, percent	9.01%	7.88%
Tier 1 capital to average assets, minimum capital requirement, amount	$ 342,346	$ 270,802
Tier 1 capital to average assets, minimum capital requirement, percent	4.00%	4.00%
Tier 1 capital to average assets, minimum to be well capitalized under prompt corrective action provisions, amount	$ 427,932	$ 338,502
Subsidiaries
Capital [Abstract]
Total capital to risk-weighted assets, actual amount	$ 954,172	$ 756,792
Total capital to risk-weighted assets, actual percent	11.17%	11.21%
Total capital to risk-weighted assets, minimum capital requirement, amount	$ 683,103	$ 539,893
Total capital to risk-weighted assets, minimum capital requirement, percent	8.00%	8.00%
Total capital to risk-weighted assets, minimum to be well capitalized under prompt corrective action provisions, amount	$ 853,879	$ 674,866
Total capital to risk-weighted assets, minimum to be well capitalized under prompt corrective action provisions, percent	10.00%	10.00%
Common Equity Tier One Risk Based Capital to Risk Weighted Assets, Amount	$ 881,324	$ 672,244
Common Equity Tier One Risk Based Capital to Risk Weighted Assets	10.32%	9.96%
Common Equity Tier One Risk Based Capital Required to be Well Capitalized to Risk Weighted Assets, Amount	$ 384,245	$ 303,690
Common Equity Tier One Risk Based Capital Required to be Well Capitalized to Risk Weighted Assets	4.50%	4.50%
Common Entity Tier 1 Capital To Risk Weighted Assets, Capital Required to be Well Capitalized	$ 555,021	$ 438,663
Common Entity Tier 1 Capital To Risk Weighted Assets, Capital Required to be Well Capitalized, Percent	6.50%	6.50%
Tier One Risk Based Capital [Abstract]
Tier 1 capital risk-weighted assets, amount	$ 881,324	$ 672,244
Tier 1 capital risk-weighted assets, percent	10.32%	9.96%
Tier 1 capital risk-weighted assets, minimum capital requirement, amount	$ 512,327	$ 404,920
Tier 1 capital risk-weighted assets, minimum capital requirement, percent	6.00%	6.00%
Tier 1 capital risk-weighted assets, minimum to be well capitalized under prompt corrective action provisions, amount	$ 683,103	$ 539,893
Tier 1 capital risk-weighted assets, minimum to be well capitalized under prompt corrective action provisions, percent	8.00%	8.00%
Tier One Leverage Capital [Abstract]
Tier 1 capital to average assets, amount	$ 881,324	$ 672,244
Tier 1 capital to average assets, percent	8.32%	7.84%
Tier 1 capital to average assets, minimum capital requirement, amount	$ 341,552	$ 269,920
Tier 1 capital to average assets, minimum capital requirement, percent	4.00%	4.00%
Tier 1 capital to average assets, minimum to be well capitalized under prompt corrective action provisions, amount	$ 426,939	$ 337,433
Tier 1 capital to average assets, minimum to be well capitalized under prompt corrective action provisions, percent	5.00%	5.00%

SHAREHOLDERS' EQUITY AND EAR121

SHAREHOLDERS' EQUITY AND EARNINGS PER COMMON SHARE - Preferred Stock (Details) - Series B Convertible Preferred Stock - shares	Dec. 31, 2017	Dec. 31, 2016
Class of Stock [Line Items]
Right to receive (shares)	0.465
Shares issued upon conversion (shares)	2
Preferred stock outstanding (shares)	521,607	0
Preferred stock issued (shares)	521,607	0

SHAREHOLDERS' EQUITY AND EAR122

SHAREHOLDERS' EQUITY AND EARNINGS PER COMMON SHARE - Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive (loss) income	$ 4,161	$ 9,766	$ (3,305)	$ 6,579
Net unrealized holding gain on AFS securities
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other accumulated comprehensive income/(loss), before tax	10,034	25,176
Income taxes related to items of accumulated other comprehensive income/(loss)	(4,026)	(9,636)
Accumulated other comprehensive (loss) income	6,008	15,540	3,880	9,916
Net (loss) on effective cash flow hedging derivatives
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other accumulated comprehensive income/(loss), before tax	0	(6,573)
Income taxes related to items of accumulated other comprehensive income/(loss)	0	2,589
Accumulated other comprehensive (loss) income	0	(3,984)	(5,108)	(1,969)
Net unrealized holding (loss) on pension plans
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other accumulated comprehensive income/(loss), before tax	(3,048)	(2,954)
Income taxes related to items of accumulated other comprehensive income/(loss)	1,201	1,164
Accumulated other comprehensive (loss) income	$ (1,847)	$ (1,790)	$ (2,077)	$ (1,368)

SHAREHOLDERS' EQUITY AND EAR123

SHAREHOLDERS' EQUITY AND EARNINGS PER COMMON SHARE - Components of Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income (loss), before reclassifications, net of tax	$ (1,925)	$ 10,257	$ (8,776)
Less: reclassification adjustment for (losses) gains realized in net income, net of tax	3,680	(2,814)	1,108
Total other comprehensive income (loss), before tax	(8,663)	21,333	(16,086)
Total income tax (expense) benefit related to other comprehensive income (loss)	3,058	(8,262)	6,202
Total other comprehensive income (loss)	(5,605)	13,071	(9,884)
Net unrealized holding (loss) on AFS securities
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income (loss), before reclassifications, before tax	(2,544)	18,308	(7,567)
Other comprehensive income (loss) before reclassifications, tax	1,075	(6,979)	2,793
Other comprehensive income (loss), before reclassifications, net of tax	(1,469)	11,329	(4,774)
Less: reclassification adjustment for (losses) realized in net income, before tax	12,598	(551)	2,110
Less: reclassification adjustment for (losses) gains realized in net income, tax	(4,535)	220	(847)
Less: reclassification adjustment for (losses) gains realized in net income, net of tax	8,063	(331)	1,263
Total other comprehensive income (loss), before tax	(15,142)	18,859	(9,677)
Total income tax (expense) benefit related to other comprehensive income (loss)	5,610	(7,199)	3,640
Total other comprehensive income (loss)	(9,532)	11,660	(6,037)
Net (loss) on cash flow hedging derivatives
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income (loss), before reclassifications, before tax	(449)	(2,022)	(5,232)
Other comprehensive income (loss) before reclassifications, tax	180	754	2,094
Other comprehensive income (loss), before reclassifications, net of tax	(269)	(1,268)	(3,138)
Less: reclassification adjustment for (losses) realized in net income, before tax	(7,022)	(3,981)	0
Less: reclassification adjustment for (losses) gains realized in net income, tax	2,769	1,589	0
Less: reclassification adjustment for (losses) gains realized in net income, net of tax	(4,253)	(2,392)	0
Total other comprehensive income (loss), before tax	6,573	1,959	(5,232)
Total income tax (expense) benefit related to other comprehensive income (loss)	(2,589)	(835)	2,094
Total other comprehensive income (loss)	3,984	1,124	(3,138)
Net unrealized holding (loss) on pension plans
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income (loss), before reclassifications, before tax	(311)	351	(1,436)
Other comprehensive income (loss) before reclassifications, tax	124	(155)	572
Other comprehensive income (loss), before reclassifications, net of tax	(187)	196	(864)
Less: reclassification adjustment for (losses) realized in net income, before tax	(217)	(164)	(259)
Less: reclassification adjustment for (losses) gains realized in net income, tax	87	73	104
Less: reclassification adjustment for (losses) gains realized in net income, net of tax	(130)	(91)	(155)
Total other comprehensive income (loss), before tax	(94)	515	(1,177)
Total income tax (expense) benefit related to other comprehensive income (loss)	37	(228)	468
Total other comprehensive income (loss)	$ (57)	$ 287	$ (709)

SHAREHOLDERS' EQUITY AND EAR124

SHAREHOLDERS' EQUITY AND EARNINGS PER COMMON SHARE - Changes in Each Component of Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance at Beginning of Year	$ 9,766	$ (3,305)	$ 6,579
Other comprehensive gain (loss) before reclassifications	(1,925)	10,257	(8,776)
Amounts reclassified from accumulated other comprehensive income	3,680	(2,814)	1,108
Total other comprehensive income (loss)	(5,605)	13,071	(9,884)
Balance at End of Period	4,161	9,766	(3,305)
Net unrealized holding (loss) on AFS securities
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance at Beginning of Year	15,540	3,880	9,916
Other comprehensive gain (loss) before reclassifications	(1,469)	11,329	(4,774)
Amounts reclassified from accumulated other comprehensive income	8,063	(331)	1,263
Total other comprehensive income (loss)	(9,532)	11,660	(6,037)
Balance at End of Period	6,008	15,540	3,880
Net (loss) on effective cash flow hedging derivatives
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance at Beginning of Year	(3,984)	(5,108)	(1,969)
Other comprehensive gain (loss) before reclassifications	(269)	(1,268)	(3,138)
Amounts reclassified from accumulated other comprehensive income	(4,253)	(2,392)	0
Total other comprehensive income (loss)	3,984	1,124	(3,138)
Balance at End of Period	0	(3,984)	(5,108)
Net unrealized holding (loss) on pension plans
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance at Beginning of Year	(1,790)	(2,077)	(1,368)
Other comprehensive gain (loss) before reclassifications	(187)	196	(864)
Amounts reclassified from accumulated other comprehensive income	(130)	(91)	(155)
Total other comprehensive income (loss)	(57)	287	(709)
Balance at End of Period	$ (1,847)	$ (1,790)	$ (2,077)

SHAREHOLDERS' EQUITY AND EAR125

SHAREHOLDERS' EQUITY AND EARNINGS PER COMMON SHARE - Amounts Reclassified Out of Each Component of Accumulated Other Comprehensive Income (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
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Non-interest income	$ 29,298	$ 28,836	$ 32,798	$ 34,757	$ 16,725	$ 18,941	$ 14,555	$ 15,630	$ 125,689	$ 65,851	$ 54,288
Income tax expense (benefit)	(22,292)	(7,211)	(8,237)	(6,762)	(362)	(6,953)	(5,249)	(6,220)	(44,502)	(18,784)	(5,064)
Interest expense	(19,457)	(17,062)	(15,121)	(13,823)	(13,276)	(12,540)	(11,577)	(10,779)	(65,463)	(48,172)	(33,181)
Non-interest expense	$ 86,366	$ 71,998	$ 69,545	$ 66,886	$ 59,158	$ 57,971	$ 57,441	$ 57,697	294,795	232,267	213,849
Income available to common shareholders									55,028	58,670	49,518
Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income available to common shareholders									3,680	(2,814)	1,108
Realized (gains) on AFS securities | Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Non-interest income									12,598	(551)	2,110
Income tax expense (benefit)									(4,535)	220	(847)
Income available to common shareholders									8,063	(331)	1,263
Realized (losses) on cash flow hedging derivatives | Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Non-interest income									(6,629)	0	0
Income tax expense (benefit)									2,769	1,589	0
Interest expense									(393)	0	0
Non-interest expense									0	(3,981)	0
Income available to common shareholders									(4,253)	(2,392)	0
Realized (losses) on pension plans | Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income tax expense (benefit)									87	73	104
Non-interest expense									(217)	(164)	(259)
Income available to common shareholders									$ (130)	$ (91)	$ (155)

SHAREHOLDERS' EQUITY AND EAR126

SHAREHOLDERS' EQUITY AND EARNINGS PER COMMON SHARE - Earnings Per Common Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ 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
Earnings Per Share Basic and Diluted [Line Items]
Net income	$ (2,810)	$ 22,903	$ 19,694	$ 15,460	$ 10,331	$ 16,381	$ 15,957	$ 16,001	$ 55,247	$ 58,670	$ 49,518
Average number of common shares issued (shares)									40,627	32,604	30,074
Less: average number of treasury shares (shares)									963	1,116	1,215
Less: average number of unvested stock award shares (shares)									437	500	466
Plus: average participating preferred shares (shares)									229	0	0
Average number of basic common shares outstanding (shares)	45,122	39,984	37,324	35,280	32,185	30,621	30,605	30,511	39,456	30,988	28,393
Average number of diluted common shares outstanding (shares)	45,122	40,145	37,474	35,452	32,381	30,811	30,765	30,688	39,695	31,167	28,564
Basic earnings per common share (USD per share)	$ (0.06)	$ 0.57	$ 0.53	$ 0.44	$ 0.32	$ 0.53	$ 0.52	$ 0.52	$ 1.40	$ 1.89	$ 1.74
Diluted earnings per common share (USD per share)	$ (0.06)	$ 0.57	$ 0.53	$ 0.44	$ 0.32	$ 0.53	$ 0.52	$ 0.52	$ 1.39	$ 1.88	$ 1.73
Restricted Stock
Earnings Per Share Basic and Diluted [Line Items]
Incremental common shares attributable to dilutive effect of share-based payment arrangements (shares)									202	122	106
Employee Stock Option
Earnings Per Share Basic and Diluted [Line Items]
Incremental common shares attributable to dilutive effect of share-based payment arrangements (shares)									37	57	65

SHAREHOLDERS' EQUITY AND EAR127

SHAREHOLDERS' EQUITY AND EARNINGS PER COMMON SHARE - Narrative (Details) - shares shares in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Employee Stock Option
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount (shares)	55	52	200

STOCK-BASED COMPENSATION PLA128

STOCK-BASED COMPENSATION PLANS - Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total compensation cost	$ 5,300,000	$ 4,600,000	$ 4,700,000
Total recognized tax benefit	$ 2,000,000	$ 1,800,000	$ 1,900,000
Weighted average fair value of stock awards granted (USD per share)	$ 35.84	$ 26.81	$ 26.66
Vesting period	5 years
Total fair value of awards vested	$ 4,400,000	$ 4,400,000	$ 3,400,000
Expected weighted-average period for recognition of unrecognized compensation	2 years
Unrecognized stock-based compensation expense	$ 6,500,000
Employee Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total compensation cost	0	0	0
Total recognized tax benefit	$ 0	0	0
Vesting period	5 years
Contractual life	10 years
Weighted average remaining contractual term for options outstanding	2 years
Total intrinsic value	$ 362,700	879,600	210,000
Unrecognized stock-based compensation expense	$ 0	$ 0	$ 0
2013 Equity Compensation Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized under the plan (shares)	1,030,000
Number of shares available for grant under the plan (shares)	383,000
2013 Equity Compensation Plan | Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares counted against the share limit for each stock granted (percent)	300.00%
2013 Equity Compensation Plan | Employee Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares counted against the share limit for each stock granted (percent)	100.00%
2011 Equity Compensation Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized under the plan (shares)	1,400,000
Number of shares available for grant under the plan (shares)	6,000
2011 Equity Compensation Plan | Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares counted against the share limit for each stock granted (percent)	300.00%
2011 Equity Compensation Plan | Employee Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares counted against the share limit for each stock granted (percent)	100.00%

STOCK-BASED COMPENSATION PLA129

STOCK-BASED COMPENSATION PLANS (Details) - $ / shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Restricted Stock
Non-vested Stock Awards Outstanding, Number of Shares
Balance at the beginning of the period (in shares)	448,000
Granted (in shares)	161,000
Stock awards vested (in shares)	(174,000)
Forfeited (in shares)	(17,000)
Balance at the end of the period (in shares)	418,000	448,000
Non-vested Stock Awards Outstanding, Weighted-Average Grant Date Fair Value
Balance at the beginning of the period (USD per share)	$ 26.28
Granted (USD per share)	35.84	$ 26.81	$ 26.66
Stock awards vested (USD per share)	25.68
Forfeited (USD per share)	30.04
Balance at the end of the period (USD per share)	$ 29.68	$ 26.28
Employee Stock Option
Stock Options Outstanding, Number of Shares
Balance at the beginning of the period (shares)	109,000
Granted (shares)	0
Exercised (shares)	(19,000)
Forfeited (shares)	0
Expired (shares)	(14,000)
Balance at the end of the period (shares)	76,000	109,000
Stock Options Outstanding, Weighted-Average Exercise Price
Balance at the beginning of the period (USD per share)	$ 15.72
Granted (USD per share)	0
Exercised (USD per share)	17.74
Forfeited (USD per share)	0
Expired (USD per share)	29.35
Balance at the end of the period (USD per share)	$ 13.59	$ 15.72

FAIR VALUE MEASUREMENTS (Detail

FAIR VALUE MEASUREMENTS (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading security	$ 12,277	$ 13,229
Available-for-securities	1,426,099	1,209,537
Other assets	117,083	98,457
Fair Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading security	12,277	13,229
Available-for-securities	1,426,099	1,209,537
Loans held for sale	153,620	120,673
Derivative assets	19,308	21,617
Derivative liabilities	15,838	24,420
Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading security	0	0
Available-for-securities	44,850	62,284
Loans held for sale	0	0
Derivative assets	0	622
Derivative liabilities	104	0
Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading security	0	0
Available-for-securities	1,381,249	1,147,253
Loans held for sale	153,620	120,673
Derivative assets	14,049	16,157
Derivative liabilities	15,715	24,420
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading security	12,277	13,229
Available-for-securities	0	0
Loans held for sale	0	0
Derivative assets	5,259	4,838
Derivative liabilities	19	0
Recurring | Fair Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading security	12,277	13,229
Loans held for sale	153,620	120,673
Derivative assets	19,308	21,617
Other assets	3,834	798
Derivative liabilities	15,838	24,420
Recurring | Fair Value | Debt securities | Municipal bonds and obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-securities	118,233	119,816
Recurring | Fair Value | Debt securities | Agency collateralized mortgage obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-securities	851,158	651,911
Recurring | Fair Value | Debt securities | Agency residential mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-securities	216,940	228,684
Recurring | Fair Value | Debt securities | Agency commercial mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-securities	62,305	64,534
Recurring | Fair Value | Debt securities | Corporate bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-securities	110,721	56,006
Recurring | Fair Value | Debt securities | Trust preferred securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-securities	11,677	11,887
Recurring | Fair Value | Debt securities | Other bonds and obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-securities	9,880	11,158
Recurring | Fair Value | Marketable equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-securities	45,185	65,541
Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading security	0	0
Loans held for sale	0	0
Derivative assets	0	622
Other assets	0	0
Derivative liabilities	104	0
Recurring | Level 1 | Debt securities | Municipal bonds and obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-securities	0	0
Recurring | Level 1 | Debt securities | Agency collateralized mortgage obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-securities	0	0
Recurring | Level 1 | Debt securities | Agency residential mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-securities	0	0
Recurring | Level 1 | Debt securities | Agency commercial mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-securities	0	0
Recurring | Level 1 | Debt securities | Corporate bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-securities	0	0
Recurring | Level 1 | Debt securities | Trust preferred securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-securities	0	0
Recurring | Level 1 | Debt securities | Other bonds and obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-securities	0	0
Recurring | Level 1 | Marketable equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-securities	44,851	62,284
Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading security	0	0
Loans held for sale	153,620	120,673
Derivative assets	14,049	16,157
Other assets	0	0
Derivative liabilities	15,715	24,420
Recurring | Level 2 | Debt securities | Municipal bonds and obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-securities	118,233	119,816
Recurring | Level 2 | Debt securities | Agency collateralized mortgage obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-securities	851,158	651,911
Recurring | Level 2 | Debt securities | Agency residential mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-securities	216,940	228,684
Recurring | Level 2 | Debt securities | Agency commercial mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-securities	62,305	64,534
Recurring | Level 2 | Debt securities | Corporate bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-securities	110,721	56,006
Recurring | Level 2 | Debt securities | Trust preferred securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-securities	11,677	11,887
Recurring | Level 2 | Debt securities | Other bonds and obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-securities	9,880	11,158
Recurring | Level 2 | Marketable equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-securities	334	3,257
Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading security	12,277	13,229
Loans held for sale	0	0
Derivative assets	5,259	4,838
Other assets	3,834	798
Derivative liabilities	19	0
Recurring | Level 3 | Debt securities | Municipal bonds and obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-securities	0	0
Recurring | Level 3 | Debt securities | Agency collateralized mortgage obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-securities	0	0
Recurring | Level 3 | Debt securities | Agency residential mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-securities	0	0
Recurring | Level 3 | Debt securities | Agency commercial mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-securities	0	0
Recurring | Level 3 | Debt securities | Corporate bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-securities	0	0
Recurring | Level 3 | Debt securities | Trust preferred securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-securities	0	0
Recurring | Level 3 | Debt securities | Other bonds and obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-securities	0	0
Recurring | Level 3 | Marketable equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-securities	$ 0	$ 0

FAIR VALUE MEASUREMENTS - Narra

FAIR VALUE MEASUREMENTS - Narrative (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2017USD ($)securitytransfer	Dec. 31, 2016USD ($)transfer	Dec. 31, 2015transfer
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Number of transfers from Level 3 to Level 2 | transfer		1
Value of transfer from Level 3 to Level 2		$ 708
Junior subordinated debentures re-price period	90 days
Origination of loans held for sale	$ 2,400,000
Sales of loans originated as held for sale	2,300,000
Loans Held for Sale
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Gain (losses) in fair value of loans held for sale included in earnings	$ 2,100	$ 2,200
Trading Security
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Number of securities in the portfolio (security) | security	1
Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Number of transfers from Level 3 to Level 2 | transfer	0		0

FAIR VALUE MEASUREMENTS - Loans

FAIR VALUE MEASUREMENTS - Loans Held for Sale (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Loans Held for Sale
Aggregate Unpaid Principal	$ 1,392	$ 0
Level 2
Loans Held for Sale
Aggregate Fair Value	153,620	120,673
Aggregate Unpaid Principal	1,392	322
Recurring | Level 2
Loans Held for Sale
Aggregate Fair Value	153,620	120,673
Recurring | Level 2 | Loans Held for Sale
Loans Held for Sale
Aggregate Fair Value	153,620	120,673
Aggregate Unpaid Principal	149,022	118,178
Aggregate Fair Value Less Aggregate Unpaid Principal	$ 4,598	$ 2,495

FAIR VALUE MEASUREMENTS - Chang

FAIR VALUE MEASUREMENTS - Changes in Level 3 Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Changes in Level 3 assets that were measured at fair value on a recurring basis
Transfers to Level 2		$ (708)
Paydown of trading security	$ 1,678	4,052	$ 3,010
Forward Commitments
Liabilities
Balance at the beginning of the period	100	9
Unrealized (loss) gain, net recognized in other non-interest income	(81)	91
Balance at the end of the period	19	100	9
Unrealized gains (losses) relating to instruments still held at the end of the period	19	100
Capitalized servicing rights
Liabilities
Balance at the beginning of the period	798	0
Unrealized (loss) gain, net recognized in other non-interest income	(221)	102
Paydown of trading security	3,257
Balance at the end of the period	3,834	798	0
Unrealized gains (losses) relating to instruments still held at the end of the period	(221)	102
Capitalized servicing rights | First Choice Bank
Liabilities
Amounts acquired from First Choice Bank		696
Trading Security
Changes in Level 3 assets that were measured at fair value on a recurring basis
Balance at the beginning of the period	13,229	14,189
Unrealized (loss) gain, net recognized in other non-interest income	(320)	(362)
Paydown of trading security	(632)	(598)
Balance at the end of the period	12,277	13,229	14,189
Liabilities
Unrealized gains (losses) relating to instruments still held at the end of the period	1,522	1,843
Securities Available for Sale
Changes in Level 3 assets that were measured at fair value on a recurring basis
Balance at the beginning of the period	0	708
Transfers to Level 2		(708)
Balance at the end of the period	0	0	708
Liabilities
Unrealized gains (losses) relating to instruments still held at the end of the period	0	0
Commitments to lend
Changes in Level 3 assets that were measured at fair value on a recurring basis
Balance at the beginning of the period	4,738	323
Unrealized (loss) gain, net recognized in other non-interest income	63,894	13,563
Transfers to loans held for sale	(63,373)	(13,048)
Balance at the end of the period	5,259	4,738	$ 323
Liabilities
Unrealized gains (losses) relating to instruments still held at the end of the period	$ 5,259	4,738
Commitments to lend | First Choice Bank
Changes in Level 3 assets that were measured at fair value on a recurring basis
Amounts acquired from First Choice Bank		$ 3,900

FAIR VALUE MEASUREMENTS - Signi

FAIR VALUE MEASUREMENTS - Significant Unobservable Inputs for Recurring Assets (Details) - Level 3 - Recurring - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Assets measured on recurring basis	$ 21,389,000	$ 18,865,000
Trading Security
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Assets measured on recurring basis	$ 12,277,000	$ 13,229,000
Trading Security | Discounted Cash Flow
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Discount Rate (percent)	2.74%	2.62%
Securities Available for Sale
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Assets measured on recurring basis		$ 100,000
Securities Available for Sale | Pricing Model
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Median Peer Price/ Tangible Book Value Percentage Multiple (percent)		80.36%
Commitments to Lend
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Assets measured on recurring basis	$ 19,000	$ 4,738,000
Commitments to Lend | Pricing Model
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Origination Costs, per loan	$ 3,692,000	$ 0.8036
Commitments to Lend | Pricing Model
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Closing Ratio (percent)	81.53%	369200.00%
Commitments to lend
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Assets measured on recurring basis	$ 5,259,000	$ 798,000
Commitments to lend | Pricing Model
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Origination Costs, per loan	$ 3,692,000	$ 0.1040
Commitments to lend | Pricing Model
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Closing Ratio (percent)	81.53%	369200.00%
Capitalized servicing rights
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Assets measured on recurring basis	$ 3,834,000
Capitalized servicing rights | Discounted Cash Flow
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Discount Rate (percent)	10.95%	11.00%
Constant prepayment rate (percent)	10.00%

FAIR VALUE MEASUREMENTS - Non-r

FAIR VALUE MEASUREMENTS - Non-recurring Fair Value Measurements (Details) - Non-recurring - Level 3 - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Assets, fair value	$ 36,380	$ 28,638
Impaired loans
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Assets, fair value	23,853	17,761
Capitalized servicing rights
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Assets, fair value	12,527	10,726
Other real estate owned
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Assets, fair value	$ 0	$ 151

FAIR VALUE MEASUREMENTS - Si136

FAIR VALUE MEASUREMENTS - Significant Unobservable Inputs for Non-recurring Assets (Details) - Non-recurring - Level 3 - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Assets, fair value	$ 36,380,000	$ 28,638,000
Impaired loans
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Assets, fair value	23,853,000	17,761,000
Impaired loans | Fair value of collateral
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Assets, fair value	$ 23,853,000	$ 17,761,000
Impaired loans | Fair value of collateral | Minimum
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Loss severity (percent)	0.21%	0.00%
Appraised value	$ 10,900	$ 0
Impaired loans | Fair value of collateral | Maximum
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Loss severity (percent)	38.72%	88.70%
Appraised value	$ 5,967,000	$ 2,192,000
Impaired loans | Fair value of collateral | Weighted Average
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Loss severity (percent)	3.40%	9.73%
Appraised value	$ 2,197,000	$ 1,026,000
Capitalized servicing rights
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Assets, fair value	12,527,000	10,726,000
Capitalized servicing rights | Discounted Cash Flow
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Assets, fair value	$ 12,527,000	$ 10,726,000
Capitalized servicing rights | Discounted Cash Flow | Minimum
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Constant prepayment rate (percent)	7.78%	7.35%
Discount Rate (percent)	10.00%	10.00%
Capitalized servicing rights | Discounted Cash Flow | Maximum
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Constant prepayment rate (percent)	12.78%	14.28%
Discount Rate (percent)	13.28%	14.00%
Capitalized servicing rights | Discounted Cash Flow | Weighted Average
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Constant prepayment rate (percent)	10.38%	10.44%
Discount Rate (percent)	11.72%	11.77%
Other real estate owned
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Assets, fair value	$ 0	$ 151,000
Other real estate owned | Fair value of collateral
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Assets, fair value	$ 0	151,000
Other real estate owned | Fair value of collateral | Minimum
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Appraised value		101,000
Other real estate owned | Fair value of collateral | Maximum
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Appraised value		129,000
Other real estate owned | Fair value of collateral | Weighted Average
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Appraised value		$ 122,000

FAIR VALUE MEASUREMENTS - Summa

FAIR VALUE MEASUREMENTS - Summary of Estimated Fair Values (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Financial Assets
Trading security	$ 12,277	$ 13,229
Securities available for sale, at fair value	1,426,099	1,209,537
Securities held to maturity	405,276	337,680
FHLB stock and restricted equity securities	63,085	71,112
Accrued interest receivable	33,739	26,113
Assets held for sale	1,392	0
Level 1
Financial Assets
Cash and cash equivalents	248,763	113,075
Trading security	0	0
Securities available for sale, at fair value	44,850	62,284
Securities held to maturity	0	0
FHLB stock and restricted equity securities	0	0
Net loans	0	0
Loans held for sale	0	0
Accrued interest receivable	0	0
Derivative assets	0	622
Assets held for sale	0	0
Financial Liabilities
Total deposits	0	0
Short-term debt	0	0
Long-term FHLB advances	0	0
Subordinated notes	0	0
Derivative liabilities	104	0
Level 2
Financial Assets
Cash and cash equivalents	0	0
Trading security	0	0
Securities available for sale, at fair value	1,381,249	1,147,253
Securities held to maturity	371,458	300,806
Net loans	0	0
Loans held for sale	153,620	120,673
Accrued interest receivable	33,739	26,113
Derivative assets	14,049	16,157
Assets held for sale	1,392	322
Financial Liabilities
Total deposits	8,731,527	6,624,108
Short-term debt	667,246	1,081,996
Long-term FHLB advances	378,766	143,151
Subordinated notes	97,414	96,973
Derivative liabilities	15,715	24,420
Level 3
Financial Assets
Cash and cash equivalents	0	0
Trading security	12,277	13,229
Securities available for sale, at fair value	0	0
Securities held to maturity	33,818	36,874
FHLB stock and restricted equity securities	0	0
Net loans	8,422,034	6,532,745
Loans held for sale	0	0
Accrued interest receivable	0	0
Derivative assets	5,259	4,838
Assets held for sale	0	0
Financial Liabilities
Total deposits	0	0
Short-term debt	0	0
Long-term FHLB advances	0	0
Subordinated notes	0	0
Derivative liabilities	19	0
Carrying Amount
Financial Assets
Cash and cash equivalents	248,763	113,075
Trading security	12,277	13,229
Securities available for sale, at fair value	1,426,099	1,209,537
Securities held to maturity	397,103	334,368
FHLB stock and restricted equity securities	63,085	71,112
Net loans	8,247,504	6,505,789
Loans held for sale	153,620	120,673
Accrued interest receivable	33,739	26,113
Derivative assets	19,308	21,617
Assets held for sale	1,392	322
Financial Liabilities
Total deposits	8,749,530	6,622,092
Short-term debt	667,300	1,082,044
Long-term FHLB advances	380,436	142,792
Subordinated notes	89,339	89,161
Derivative liabilities	15,838	24,420
Fair Value
Financial Assets
Cash and cash equivalents	248,763	113,075
Trading security	12,277	13,229
Securities available for sale, at fair value	1,426,099	1,209,537
Securities held to maturity	405,276	337,680
Net loans	8,422,034	6,532,745
Loans held for sale	153,620	120,673
Accrued interest receivable	33,739	26,113
Derivative assets	19,308	21,617
Assets held for sale	1,392	322
Financial Liabilities
Total deposits	8,731,527	6,624,108
Short-term debt	667,246	1,081,996
Long-term FHLB advances	378,766	143,151
Subordinated notes	97,414	96,973
Derivative liabilities	$ 15,838	$ 24,420

CONDENSED FINANCIAL STATEMEN138

CONDENSED FINANCIAL STATEMENTS OF PARENT COMPANY - Condensed Balance Sheets (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Assets
Cash due from Berkshire Bank	$ 91,122	$ 71,494
Securities available for sale, at fair value	1,426,099	1,209,537
Other assets	117,083	98,457
Total assets	11,570,751	9,162,542
Liabilities and Shareholders’ Equity
Short-term debt	667,300	1,082,044
Subordinated notes	89,339	89,161
Shareholders’ equity	1,496,264	1,093,298	$ 887,189	$ 709,287
Total liabilities and shareholders’ equity	11,570,751	9,162,542
Reportable legal entity | Berkshire Hills Bancorp
Condensed balance sheets
Intercompany subordinated notes	35,000
Assets
Cash due from Berkshire Bank	83,380	43,018
Investment in subsidiaries	1,470,859	1,127,706
Securities available for sale, at fair value	21,827	23,651
Other assets	12,138	1,372
Total assets	1,588,204	1,195,747
Liabilities and Shareholders’ Equity
Short-term debt	0	10,000
Subordinated notes	89,339	89,161
Accrued expenses	2,601	3,288
Shareholders’ equity	1,496,264	1,093,298
Total liabilities and shareholders’ equity	$ 1,588,204	$ 1,195,747

CONDENSED FINANCIAL STATEMEN139

CONDENSED FINANCIAL STATEMENTS OF PARENT COMPANY - Condensed Statements of Income (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:
Total net revenue	$ 115,664	$ 100,834	$ 102,343	$ 101,643	$ 75,883	$ 76,912	$ 71,996	$ 73,327	$ 420,484	$ 298,118	$ 268,137
Interest expense	19,457	17,062	15,121	13,823	13,276	12,540	11,577	10,779	65,463	48,172	33,181
Income tax benefit	22,292	7,211	8,237	6,762	362	6,953	5,249	6,220	44,502	18,784	5,064
Net income	$ (2,810)	$ 22,903	$ 19,694	$ 15,460	$ 10,331	$ 16,381	$ 15,957	$ 16,001	55,247	58,670	49,518
Preferred stock dividend									219	0	0
Income available to common shareholders									55,028	58,670	49,518
Reportable legal entity | Berkshire Hills Bancorp
Income:
Dividends from subsidiaries									39,000	33,000	34,000
Other									5,864	4,072	2,763
Total net revenue									44,864	37,072	36,763
Interest expense									5,338	5,743	5,674
Non-interest expenses									6,042	3,740	3,670
Total expense									11,380	9,483	9,344
Income before income taxes and equity in undistributed income of subsidiaries									33,484	27,589	27,419
Income tax benefit									(1,783)	(2,123)	(2,518)
Income before equity in undistributed income of subsidiaries									35,267	29,712	29,937
Equity in undistributed income of subsidiaries									19,980	28,958	19,581
Net income									55,247	58,670	49,518
Preferred stock dividend									219	0	0
Income available to common shareholders									$ 55,028	$ 58,670	$ 49,518

CONDENSED FINANCIAL STATEMEN140

CONDENSED FINANCIAL STATEMENTS OF PARENT COMPANY - Condensed Statements of Cash Flows (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
Condensed statements of cash flows
Net income	$ (2,810)	$ 22,903	$ 19,694	$ 15,460	$ 10,331	$ 16,381	$ 15,957	$ 16,001	$ 55,247	$ 58,670	$ 49,518
Adjustments to reconcile net income to net cash (used) provided by operating activities:
Other, net									19,254	3,309	4,458
Net cash provided by operating activities									78,091	98,142	86,288
Cash flows from investing activities:
Acquisitions, net of cash paid									374,611	(48,180)	74,324
Other, net									(5,102)	(7,616)	(5,105)
Net cash used in investing activities									(282,903)	(207,595)	(454,492)
Cash flows from financing activities:
Net proceeds from common stock									152,985	0	0
Payment to repurchase common stock									0	0	(550)
Cash dividends paid									(33,241)	(24,916)	(21,903)
Net cash provided by financing activities									340,500	118,966	400,012
Net change in cash and cash equivalents									135,688	9,513	31,808
Cash and cash equivalents at beginning of year				113,075					113,075
Cash and cash equivalents at end of year	248,763				113,075				248,763	113,075
Reportable legal entity | Berkshire Hills Bancorp
Condensed statements of cash flows
Net income									55,247	58,670	49,518
Adjustments to reconcile net income to net cash (used) provided by operating activities:
Equity in undistributed income of subsidiaries									(19,980)	(28,958)	(19,581)
Other, net									(7,964)	1,988	10,904
Net cash provided by operating activities									27,303	31,700	40,841
Cash flows from investing activities:
Advances to subsidiaries									(100,000)	0	0
Acquisitions, net of cash paid									0	0	(3,293)
Purchase of securities									(1,057)	(18,016)	(18)
Sale of securities									2,101	0	0
Other, net									1,508	9,728	0
Net cash used in investing activities									(97,448)	(8,288)	(3,311)
Cash flows from financing activities:
Proceed from issuance of short term debt									0	9,349	0
Repayment of short term debt									(9,822)	0	(9,935)
Net proceeds from common stock									153,313	3,712	0
Net proceeds from preferred stock									0	0	0
Net proceeds from reissuance of treasury stock									0	0	240
Payment to repurchase common stock									0	(4,632)	(550)
Cash dividends paid									(33,022)	(24,916)	(21,903)
Preferred stock cash dividends paid									(219)	0	0
Other, net									257	11	167
Net cash provided by financing activities									110,507	(16,476)	(31,981)
Net change in cash and cash equivalents									40,362	6,936	5,549
Cash and cash equivalents at beginning of year				$ 43,018				$ 36,082	43,018	36,082	30,533
Cash and cash equivalents at end of year	$ 83,380				$ 43,018				$ 83,380	$ 43,018	$ 36,082

QUARTERLY DATA (UNAUDITED) (Det

QUARTERLY DATA (UNAUDITED) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ 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 and dividend income	$ 105,823	$ 89,060	$ 84,666	$ 80,709	$ 72,434	$ 70,511	$ 69,018	$ 68,476	$ 360,258	$ 280,439	$ 247,030
Interest expense	19,457	17,062	15,121	13,823	13,276	12,540	11,577	10,779	65,463	48,172	33,181
Net interest income	86,366	71,998	69,545	66,886	59,158	57,971	57,441	57,697	294,795	232,267	213,849
Total non-interest income	29,298	28,836	32,798	34,757	16,725	18,941	14,555	15,630	125,689	65,851	54,288
Total net revenue	115,664	100,834	102,343	101,643	75,883	76,912	71,996	73,327	420,484	298,118	268,137
Provision for loan losses	6,141	4,900	4,889	5,095	4,100	4,734	4,522	4,006	21,025	17,362	16,726
Non-interest expense	90,041	65,820	69,523	74,326	61,090	48,844	46,268	47,100	299,710	203,302	196,829
Income from continuing operations before income taxes	19,482	30,114	27,931	22,222	10,693	23,334	21,206	22,221	99,749	77,454	54,582
Income tax expense	22,292	7,211	8,237	6,762	362	6,953	5,249	6,220	44,502	18,784	5,064
Net (loss)/income	$ (2,810)	$ 22,903	$ 19,694	$ 15,460	$ 10,331	$ 16,381	$ 15,957	$ 16,001	$ 55,247	$ 58,670	$ 49,518
Basic (loss)/earnings per common share (USD per share)	$ (0.06)	$ 0.57	$ 0.53	$ 0.44	$ 0.32	$ 0.53	$ 0.52	$ 0.52	$ 1.40	$ 1.89	$ 1.74
Diluted (loss)/earnings per share (USD per share)	$ (0.06)	$ 0.57	$ 0.53	$ 0.44	$ 0.32	$ 0.53	$ 0.52	$ 0.52	$ 1.39	$ 1.88	$ 1.73
Weighted average common shares outstanding:
Basic (shares)	45,122	39,984	37,324	35,280	32,185	30,621	30,605	30,511	39,456	30,988	28,393
Diluted (shares)	45,122	40,145	37,474	35,452	32,381	30,811	30,765	30,688	39,695	31,167	28,564
Write down of net deferred tax asset									$ 18,100

NET INTEREST INCOME AFTER PR142

NET INTEREST INCOME AFTER PROVISION FOR LOAN 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
Banking and Thrift, Interest [Abstract]
Net interest income	$ 86,366	$ 71,998	$ 69,545	$ 66,886	$ 59,158	$ 57,971	$ 57,441	$ 57,697	$ 294,795	$ 232,267	$ 213,849
Provision for loan losses	6,141	4,900	4,889	5,095	4,100	4,734	4,522	4,006	21,025	17,362	16,726
Net interest income after provision for loan losses									273,770	214,905	197,123
Total non-interest income	29,298	28,836	32,798	34,757	16,725	18,941	14,555	15,630	125,689	65,851	54,288
Total non-interest expense	90,041	65,820	69,523	74,326	61,090	48,844	46,268	47,100	299,710	203,302	196,829
Income from continuing operations before income taxes	19,482	30,114	27,931	22,222	10,693	23,334	21,206	22,221	99,749	77,454	54,582
Income tax expense	22,292	7,211	8,237	6,762	362	6,953	5,249	6,220	44,502	18,784	5,064
Net income	$ (2,810)	$ 22,903	$ 19,694	$ 15,460	$ 10,331	$ 16,381	$ 15,957	$ 16,001	$ 55,247	$ 58,670	$ 49,518