Community Bank System (CBU) 10-Q 9 Nov 18 2018 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2018	Oct. 31, 2018
Document and Entity Information [Abstract]
Entity Registrant Name	COMMUNITY BANK SYSTEM, INC.
Entity Central Index Key	723,188
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Ex Transition Period	false
Entity Common Stock, Shares Outstanding		51,186,421
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	Q3

CONSOLIDATED STATEMENTS OF COND

CONSOLIDATED STATEMENTS OF CONDITION (Unaudited) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Assets:
Cash and cash equivalents	$ 256,838	$ 221,038
Available-for-sale investment securities (cost of $2,957,819 and $3,007,148, respectively)	2,904,779	3,031,088
Equity and other securities (cost of $42,281 and $50,291, respectively)	43,278	50,291
Loans held for sale, at fair value	0	461
Loans	6,300,888	6,256,757
Allowance for loan losses	(50,133)	(47,583)
Net loans	6,250,755	6,209,174
Goodwill, net	733,479	734,430
Core deposit intangibles, net	20,112	25,025
Other intangibles, net	58,109	65,633
Intangible assets, net	811,700	825,088
Premises and equipment, net	120,273	123,393
Accrued interest and fees receivable	34,594	36,177
Other assets	237,350	249,488
Total assets	10,659,567	10,746,198
Liabilities:
Noninterest-bearing deposits	2,346,932	2,293,057
Interest-bearing deposits	6,116,889	6,151,363
Total deposits	8,463,821	8,444,420
Short-term borrowings	0	24,000
Securities sold under agreement to repurchase, short-term	274,561	337,011
Other long-term debt	1,998	2,071
Subordinated debt held by unconsolidated subsidiary trusts	97,939	122,814
Accrued interest and other liabilities	152,903	180,567
Total liabilities	8,991,222	9,110,883
Commitments and contingencies (See Note J)
Shareholders' equity:
Preferred stock, $1.00 par value, 500,000 shares authorized, 0 shares issued	0	0
Common stock, $1.00 par value, 75,000,000 shares authorized; 51,547,253 and 51,263,841 shares issued, respectively	51,547	51,264
Additional paid-in capital	907,690	894,879
Retained earnings	774,403	700,557
Accumulated other comprehensive loss	(62,142)	(3,699)
Treasury stock, at cost (410,577 shares including 206,151 shares held by deferred compensation arrangements at September 30, 2018, and 567,764 shares including 237,494 shares held by deferred compensation arrangements at December 31, 2017, respectively)	(14,803)	(21,014)
Deferred compensation arrangements (206,151 and 237,494 shares, respectively)	11,650	13,328
Total shareholders' equity	1,668,345	1,635,315
Total liabilities and shareholders' equity	$ 10,659,567	$ 10,746,198

CONSOLIDATED STATEMENTS OF CO_2

CONSOLIDATED STATEMENTS OF CONDITION (Unaudited) (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Assets:
Available-for-sale investment securities, cost	$ 2,957,819	$ 3,007,148
Equity and other securities, cost	$ 42,281	$ 50,291
Shareholders' equity:
Preferred stock, par value (in dollars per share)	$ 1	$ 1
Preferred stock, shares authorized (in shares)	500,000	500,000
Preferred stock, shares issued (in shares)	0	0
Common stock, par value (in dollars per share)	$ 1	$ 1
Common stock, shares authorized (in shares)	75,000,000	75,000,000
Common stock, shares issued (in shares)	51,547,253	51,263,841
Treasury stock, shares at cost (in shares)	410,577	567,764
Shares held by deferred compensation arrangements (in shares)	206,151	237,494

CONSOLIDATED STATEMENTS OF INCO

CONSOLIDATED STATEMENTS OF INCOME (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Interest income:
Interest and fees on loans	$ 72,256	$ 69,498	$ 212,849	$ 184,233
Interest and dividends on taxable investments	15,421	15,228	47,462	43,969
Interest on nontaxable investments	3,226	3,761	10,001	11,665
Total interest income	90,903	88,487	270,312	239,867
Interest expense:
Interest on deposits	2,764	2,123	7,277	5,918
Interest on borrowings	796	902	1,722	1,443
Interest on subordinated debt held by unconsolidated subsidiary trusts	1,145	1,067	3,645	2,808
Total interest expense	4,705	4,092	12,644	10,169
Net interest income	86,198	84,395	257,668	229,698
Provision for loan losses	2,215	2,314	8,342	5,603
Net interest income after provision for loan losses	83,983	82,081	249,326	224,095
Noninterest revenues:
Deposit service fees	16,127	18,419	54,268	49,781
Other banking services	1,536	1,704	3,942	4,270
Employee benefit services	23,265	20,767	68,813	58,618
Insurance services	8,270	6,344	23,044	19,709
Wealth management services	6,168	5,707	19,370	16,105
Unrealized gain on equity securities	743	0	722	0
Loss on debt extinguishment	(318)	0	(318)	0
Gain on sales of investment securities	0	0	0	2
Total noninterest revenues	55,791	52,941	169,841	148,485
Noninterest expenses:
Salaries and employee benefits	51,062	48,426	155,323	137,897
Occupancy and equipment	9,770	9,106	29,738	25,939
Data processing and communications	10,509	9,313	29,463	28,229
Amortization of intangible assets	4,427	4,949	13,780	11,980
Legal and professional fees	2,522	2,764	8,047	7,796
Business development and marketing	2,587	2,586	7,301	7,119
Acquisition expenses	(832)	580	(769)	25,192
Other expenses	5,188	6,052	14,793	16,078
Total noninterest expenses	85,233	83,776	257,676	260,230
Income before income taxes	54,541	51,246	161,491	112,350
Income taxes	11,435	16,003	33,673	33,659
Net income	$ 43,106	$ 35,243	$ 127,818	$ 78,691
Basic earnings per share (in dollars per share)	$ 0.84	$ 0.69	$ 2.49	$ 1.62
Diluted earnings per share (in dollars per share)	0.83	0.68	2.46	1.60
Cash dividends declared per share (in dollars per share)	$ 0.38	$ 0.34	$ 1.06	$ 0.98

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Pension and other post retirement obligations:
Amortization of actuarial losses included in net periodic pension cost, gross	$ 304	$ 150	$ 910	$ 625
Tax effect	(74)	(57)	(221)	(240)
Amortization of actuarial losses included in net periodic pension cost, net	230	93	689	385
Amortization of prior service cost included in net periodic pension cost, gross	(105)	(32)	(359)	(91)
Tax effect	25	12	87	35
Amortization of prior service cost included in net periodic pension cost, net	(80)	(20)	(272)	(56)
Initial projected benefit obligation recognized upon plan adoption, gross (See Note H)	(775)	0	(775)	0
Tax effect	189	0	189	0
Initial projected benefit obligation recognized upon plan adoption, net	(586)	0	(586)	0
Unamortized actuarial gain due to plan merger, gross (See Note H)	0	0	0	1,858
Tax effect	0	0	0	(710)
Unamortized actuarial gain due to plan merger, net	0	0	0	1,148
Other comprehensive (loss) income related to pension and other post retirement obligations, net of taxes	(436)	73	(169)	1,477
Unrealized (losses) gains on available-for-sale securities:
Net unrealized holding (losses)/gains arising during period, gross	(20,094)	(2,490)	(76,705)	11,163
Tax effect	4,879	952	18,639	(4,306)
Net unrealized holding (losses)/gains arising during period, net	(15,215)	(1,538)	(58,066)	6,857
Reclassification of other comprehensive income due to change in accounting principle - equity securities	0	0	(208)	0
Other comprehensive (loss)/income related to unrealized (losses)/gains on available-for-sale securities, net of taxes	(15,215)	(1,538)	(58,274)	6,857
Other comprehensive (loss)/income, net of tax	(15,651)	(1,465)	(58,443)	8,334
Net income	43,106	35,243	127,818	78,691
Comprehensive income	27,455	$ 33,778	69,375	$ 87,025
Accumulated Other Comprehensive Loss By Component:
Unrealized loss for pension and other post-retirement obligations	(28,901)		(28,901)		$ (28,677)
Tax effect	7,099		7,099		7,044
Net unrealized loss for pension and other post-retirement obligations	(21,802)		(21,802)		(21,633)
Unrealized (loss) gain on available-for-sale securities	(53,040)		(53,040)		23,940
Tax effect	12,908		12,908		(6,006)
Reclassification of other comprehensive income due to change in accounting principle - equity securities	(208)		(208)		0
Net unrealized (loss) gain on available-for-sale securities	(40,340)		(40,340)		17,934
Accumulated other comprehensive loss	$ (62,142)		$ (62,142)		$ (3,699)

CONSOLIDATED STATEMENT OF CHANG

CONSOLIDATED STATEMENT OF CHANGES IN SHAREHOLDERS' EQUITY (Unaudited) - USD ($) $ in Thousands	Common Stock [Member]	Additional Paid-In Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Loss [Member]	Treasury Stock [Member]	Deferred Compensation Arrangements [Member]	Total
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect of change in accounting principle - equity securities			$ 208	$ (208)			$ 0
Balance at Dec. 31, 2017	$ 51,264	$ 894,879	700,557	(3,699)	$ (21,014)	$ 13,328	1,635,315
Balance (in shares) at Dec. 31, 2017	50,696,077
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income			127,818				127,818
Other comprehensive loss, net of tax				(58,235)			(58,235)
Cash dividends declared:
Common, $1.06 per share			(54,180)				(54,180)
Common stock issued under employee stock ownership plan	$ 283	5,511					5,794
Common stock issued under employee stock ownership plan (in shares)	283,412
Stock-based compensation		4,607					4,607
Distribution of stock under deferred compensation arrangements					1,898	(1,898)	0
Distribution of stock under deferred compensation arrangements (in shares)	35,233
Treasury stock issued to benefit plans, net		2,693			4,313	220	7,226
Treasury stock issued to benefit plans, net (in shares)	121,954
Balance at Sep. 30, 2018	$ 51,547	$ 907,690	$ 774,403	$ (62,142)	$ (14,803)	$ 11,650	$ 1,668,345
Balance (in shares) at Sep. 30, 2018	51,136,676

CONSOLIDATED STATEMENT OF CHA_2

CONSOLIDATED STATEMENT OF CHANGES IN SHAREHOLDERS' EQUITY (Unaudited) (Parenthetical) - $ / shares	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Cash dividends declared:
Dividends declared per common share (in dollars per share)	$ 0.38	$ 0.34	$ 1.06	$ 0.98

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Operating activities:
Net income	$ 127,818	$ 78,691
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	11,854	12,026
Amortization of intangible assets	13,780	11,980
Net accretion on securities, loans and borrowings	(7,141)	(4,412)
Stock-based compensation	4,607	3,985
Provision for loan losses	8,342	5,603
Amortization of mortgage servicing rights	340	374
Unrealized gain on equity securities	(722)	0
Loss on debt extinguishment	318	0
Income from bank-owned life insurance policies	(1,177)	(1,170)
Net (gain) loss on sale of loans and other assets	(207)	155
Change in other assets and other liabilities	8,769	31,624
Net cash provided by operating activities	166,581	138,856
Investing activities:
Proceeds from maturities of available-for-sale investment securities	102,549	110,160
Proceeds from maturities of other investment securities	8,292	28,580
Purchases of available-for-sale investment securities	(47,495)	(59,425)
Purchases of other securities	(31)	(12,434)
Net (increase) decrease in loans	(51,170)	120,029
Cash paid for acquisitions, net of cash acquired of $16 and $51,793, respectively	(1,737)	(105,402)
Settlement of bank-owned life insurance policies	0	1,779
Purchases of premises and equipment, net	(8,903)	(7,701)
Net cash provided by investing activities	1,505	75,586
Financing activities:
Net increase in deposits	19,401	81,630
Net decrease in borrowings	(86,523)	(193,602)
Payments on subordinated debt held by unconsolidated subsidiary trusts	(25,207)	0
Issuance of common stock	5,794	3,740
Purchases of treasury stock	(220)	(3,226)
Sales of treasury stock	7,226	7,861
Increase in deferred compensation arrangements	220	3,226
Cash dividends paid	(52,006)	(45,059)
Withholding taxes paid on share-based compensation	(971)	(1,389)
Net cash used in financing activities	(132,286)	(146,819)
Change in cash and cash equivalents	35,800	67,623
Cash and cash equivalents at beginning of period	221,038	173,857
Cash and cash equivalents at end of period	256,838	241,480
Supplemental disclosures of cash flow information:
Cash paid for interest	12,870	10,092
Cash paid for income taxes	20,674	33,187
Supplemental disclosures of noncash financing and investing activities:
Dividends declared and unpaid	19,634	17,412
Transfers from loans to other real estate	2,426	2,470
Acquisitions:
Common stock issued	0	340,737
Fair value of assets acquired, excluding acquired cash and intangibles	115	1,960,922
Fair value of liabilities assumed	$ 31	$ 1,869,854

CONSOLIDATED STATEMENTS OF CA_2

CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) (Parenthetical) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Investing activities:
Cash acquired from acquisition	$ 16	$ 51,793

BASIS OF PRESENTATION

BASIS OF PRESENTATION	9 Months Ended
	Sep. 30, 2018
BASIS OF PRESENTATION [Abstract]
BASIS OF PRESENTATION	NOTE A: BASIS OF PRESENTATION The interim financial data as of and for the three and nine months ended September 30, 2018 is unaudited; however, in the opinion of Community Bank System, Inc. (the “Company”), the interim data includes all adjustments, consisting only of normal recurring adjustments, necessary for a fair statement of the results for the interim periods in conformity with generally accepted accounting principles (“GAAP”). The results of operations for the interim periods are not necessarily indicative of the results that may be expected for the full year or any other interim period.

ACQUISITIONS

ACQUISITIONS	9 Months Ended
	Sep. 30, 2018
ACQUISITIONS [Abstract]
ACQUISITIONS	NOTE B: ACQUISITIONS On April 2, 2018, the Company, through its subsidiary, Benefit Plans Administrative Services, Inc. (“BPAS”), acquired certain assets of HR Consultants (SA), LLC (“HR Consultants”), a benefits consulting group headquartered in Puerto Rico. The Company paid $0.3 million in cash to acquire the assets of HR Consultants and recorded intangible assets of $0.3 million in conjunction with the acquisition. The effects of the acquired assets have been included in the consolidated financial statements since that date. On January 2, 2018, the Company, through its subsidiary, OneGroup NY, Inc. (“OneGroup”), completed its acquisition of certain assets of Penna & Associates Agency, Inc. (“Penna”), an insurance agency headquartered in Johnson City, New York. The Company paid $0.8 million in cash to acquire the assets of Penna, and recorded goodwill in the amount of $0.3 million and a customer list intangible asset of $0.3 million in conjunction with the acquisition. The effects of the acquired assets have been included in the consolidated financial statements since that date. On January 2, 2018, the Company, through its subsidiary, Community Investment Services, Inc. (“CISI”), completed its acquisition of certain assets of Styles Bridges Associates (“Styles Bridges”), a financial services business headquartered in Canton, New York. The Company paid $0.7 million in cash to acquire a customer list from Styles Bridges, and recorded a $0.7 million customer list intangible asset in conjunction with the acquisition. The effects of the acquired assets have been included in the consolidated financial statements since that date. On December 4, 2017, the Company, through its subsidiary, OneGroup, completed its acquisition of Gordon B. Roberts Agency, Inc. (“GBR”), an insurance agency headquartered in Oneonta, New York for $3.7 million in Company stock and cash, comprised of $1.35 million in cash and the issuance of 0.04 million shares of common stock. The transaction resulted in the acquisition of $0.6 million of assets, $0.6 million of other liabilities, goodwill in the amount of $2.1 million and other intangible assets of $1.6 million. The effects of the acquired assets and liabilities have been included in the consolidated financial statements since that date. On November 17, 2017, the Company, through its subsidiary, CISI, completed its acquisition of certain assets of Northeast Capital Management, Inc. (“NECM”), a financial services business headquartered in Wilkes Barre, Pennsylvania. The Company paid $1.2 million in cash to acquire a customer list from NECM, and recorded a $1.2 million customer list intangible asset in conjunction with the acquisition. The effects of the acquired assets have been included in the consolidated financial statements since that date. On May 12, 2017, the Company completed its acquisition of Merchants Bancshares, Inc. (“Merchants”), parent company of Merchants Bank, headquartered in South Burlington, Vermont, for $345.2 million in Company stock and cash, comprised of $82.9 million in cash and the issuance of 4.68 million shares of common stock. The acquisition extends the Company’s footprint into the Vermont and Western Massachusetts markets with the addition of 31 branch locations in Vermont and one location in Massachusetts. This transaction resulted in the acquisition of $2.0 billion of assets, including $1.49 billion of loans and $370.6 million of investment securities, as well as $1.45 billion of deposits and $189.0 million in goodwill. The effects of the acquired assets and liabilities have been included in the consolidated financial statements since that date. Revenues of approximately $14.7 million and $46.8 million from Merchants were included in the consolidated income statement for the three and nine months ended September 30, 2018, respectively. Direct expenses, which may not include certain shared expenses, of approximately $7.4 million and $22.7 million from Merchants were included in the consolidated income statement for the three and nine months ended September 30, 2018, respectively. Revenues of approximately $16.8 million and $25.8 million from Merchants were included in the consolidated income statement for the three and nine months ended September 30, 2017, respectively. Direct expenses, which may not include certain shared expenses, of approximately $7.5 million and $11.5 million from Merchants were included in the consolidated income statement for the three and nine months ended September 30, 2017, respectively. On March 1, 2017, the Company, through its subsidiary, OneGroup, completed its acquisition of certain assets of Dryfoos Insurance Agency, Inc. (“Dryfoos”), an insurance agency headquartered in Hazleton, Pennsylvania. The Company paid $3.0 million in cash to acquire the assets of Dryfoos, and recorded goodwill in the amount of $1.7 million and other intangible assets of $1.7 million in conjunction with the acquisition. The effects of the acquired assets and liabilities have been included in the consolidated financial statements since that date. On February 3, 2017, the Company completed its acquisition of Northeast Retirement Services, Inc. (“NRS”) and its subsidiary Global Trust Company (“GTC”), headquartered in Woburn, Massachusetts, for $148.6 million in Company stock and cash. NRS was a privately held corporation focused on providing institutional transfer agency, master recordkeeping services, custom target date fund administration, trust product administration and customized reporting services to institutional clients. Its wholly-owned subsidiary, GTC, is chartered in the State of Maine as a non-depository trust company and provides fiduciary services for collective investment trusts and other products. The acquisition of NRS and GTC, hereafter referred to collectively as NRS, strengthens and complements the Company’s existing employee benefit services businesses. Upon the completion of the merger, NRS became a wholly-owned subsidiary of BPAS and operates as Northeast Retirement Services, LLC, a Delaware limited liability company. This transaction resulted in the acquisition of $36.1 million in net tangible assets, principally cash and certificates of deposit, $60.2 million in customer list intangibles that will be amortized using the 150% declining balance method over 10 years, a $23.0 million deferred tax liability associated with the customer list intangible, and $75.3 million in goodwill. The effects of the acquired assets and liabilities have been included in the consolidated financial statements since that date. Revenues of $10.3 million and $30.1 million from NRS were included in the consolidated statements of income for the three and nine months ended September 30, 2018, respectively. Expenses of $6.1 million and $18.1 million from NRS were included in the consolidated statements of income for the three and nine months ended September 30, 2018, respectively. Revenues of $8.7 million and $22.1 million from NRS were included in the consolidated income statement for the three and nine months ended September 30, 2017, respectively. Expenses of $5.8 million and $15.1 million from NRS were included in the consolidated income statement for the three and nine months ended September 30, 2017, respectively. On January 1, 2017, the Company, through its subsidiary, OneGroup, acquired certain assets of Benefits Advisory Service, Inc. (“BAS”), a benefits consulting group headquartered in Forest Hills, New York. The Company paid $1.2 million in cash to acquire the assets of BAS and recorded intangible assets of $1.2 million in conjunction with the acquisition. The effects of the acquired assets have been included in the consolidated financial statements since that date. The assets and liabilities assumed in the acquisitions were recorded at their estimated fair values based on management's best estimates using information available at the dates of the acquisition, and were subject to adjustment based on updated information not available at the time of acquisition. During the first quarter of 2018, the carrying amount of other liabilities associated with the NRS acquisition decreased by $1.2 million as a result of an adjustment to deferred taxes. Goodwill associated with the NRS acquisition decreased $1.2 million as a result of this adjustment. During the second quarter of 2018, the carrying amount of other liabilities associated with the GBR acquisition decreased by $0.09 million as a result of updated information not available at the time of acquisition. Goodwill associated with the GBR acquisition decreased $0.09 million as a result of this adjustment. The above referenced acquisitions expanded the Company’s geographical presence in New York, Pennsylvania, Vermont, and Western Massachusetts and management expects that the Company will benefit from greater geographic diversity and the advantages of other synergistic business development opportunities. The following table summarizes the estimated fair value of the assets acquired and liabilities assumed after considering the measurement period adjustments described above: 2018 2017 (000s omitted) Other (1) NRS Merchants Other (2) Total Consideration paid : Cash $ 1,753 $ 70,073 $ 82,898 $ 6,775 $ 159,746 Community Bank System, Inc. common stock 0 78,483 262,254 2,395 343,132 Total net consideration paid 1,753 148,556 345,152 9,170 502,878 Recognized amounts of identifiable assets acquired and liabilities assumed: Cash and cash equivalents 16 11,063 40,730 339 52,132 Investment securities 0 20,294 370,648 0 390,942 Loans 0 0 1,488,157 0 1,488,157 Premises and equipment 10 411 16,608 27 17,046 Accrued interest receivable 0 72 4,773 0 4,845 Other assets 105 8,088 51,585 583 60,256 Core deposit intangibles 0 0 23,214 0 23,214 Other intangibles 1,343 60,200 2,857 5,626 68,683 Deposits 0 0 (1,448,406 ) 0 (1,448,406 ) Other liabilities (31 ) (26,828 ) (11,750 ) (1,131 ) (39,709 ) Short-term advances 0 0 (80,000 ) 0 (80,000 ) Securities sold under agreement to repurchase, short-term 0 0 (278,076 ) 0 (278,076 ) Long-term debt 0 0 (3,615 ) 0 (3,615 ) Subordinated debt held by unconsolidated subsidiary trusts 0 0 (20,619 ) 0 (20,619 ) Total identifiable assets, net 1,443 73,300 156,106 5,444 234,850 Goodwill $ 310 $ 75,256 $ 189,046 $ 3,726 $ 268,028 (1) (2) Acquired loans that have evidence of deterioration in credit quality since origination and for which it is probable, at acquisition, that the Company will be unable to collect all contractually required payments were aggregated by comparable characteristics and recorded at fair value without a carryover of the related allowance for loan losses. Cash flows for each loan were determined using an estimate of credit losses and rate of prepayments. Projected monthly cash flows were then discounted to present value using a market-based discount rate. The excess of the undiscounted expected cash flows over the estimated fair value is referred to as the “accretable yield” and is recognized into interest income over the remaining lives of the acquired loans. The following is a summary of the loans acquired from Merchants at the date of acquisition: (000s omitted) Acquired Impaired Loans Acquired Non-impaired Loans Total Acquired Loans Contractually required principal and interest at acquisition $ 15,454 $ 1,872,574 $ 1,888,028 Contractual cash flows not expected to be collected (5,385 ) (14,753 ) (20,138 ) Expected cash flows at acquisition 10,069 1,857,821 1,867,890 Interest component of expected cash flows (793 ) (378,940 ) (379,733 ) Fair value of acquired loans $ 9,276 $ 1,478,881 $ 1,488,157 The fair value of checking, savings and money market deposit accounts acquired were assumed to approximate the carrying value as these accounts have no stated maturity and are payable on demand. Certificate of deposit accounts were valued at the present value of the certificates’ expected contractual payments discounted at market rates for similar certificates. The core deposit intangibles and other intangibles related to the HR Consultants, Penna, Styles Bridges, GBR, NECM, Merchants, Dryfoos, and BAS acquisitions are being amortized using an accelerated method over their estimated useful life of eight years. The goodwill, which is not amortized for book purposes, was assigned to the Banking segment for the Merchants acquisition, the Employee Benefit Services segment for NRS, and All Other segments for the Penna, GBR, and Dryfoos acquisitions. Goodwill arising from the Merchants, NRS and GBR acquisitions is not deductible for tax purposes. Goodwill arising from the Penna and Dryfoos acquisitions is deductible for tax purposes. Direct costs related to the acquisitions were expensed as incurred. During the three and nine months ended September 30, 2018, the Company recognized merger and acquisition integration-related recoveries in the amount of $0.8 million due to an adjustment of contract termination expenses related to the Merchants acquisition that have been separately stated in the Consolidated Statements of Income. Merger and acquisition integration-related expenses amount to $0.6 million and $25.2 million during the three and nine months ended September 30, 2017 and have been separately stated in the Consolidated Statements of Income.

ACCOUNTING POLICIES

ACCOUNTING POLICIES	9 Months Ended
	Sep. 30, 2018
ACCOUNTING POLICIES [Abstract]
ACCOUNTING POLICIES	NOTE C: ACCOUNTING POLICIES The accounting policies of the Company, as applied in the consolidated interim financial statements presented herein, are substantially the same as those followed on an annual basis as presented on pages 63 through 71 of the Annual Report on Form 10-K for the year ended December 31, 2017 filed with the Securities and Exchange Commission (“SEC”) on March 1, 2018. Investment Securities The Company can classify its investments in debt securities as held-to-maturity, available-for-sale, or trading. Held-to-maturity securities are those for which the Company has the positive intent and ability to hold until maturity, and are reported at cost, which is adjusted for amortization of premiums and accretion of discounts. Available-for-sale debt securities are reported at fair value with net unrealized gains and losses reflected as a separate component of shareholders' equity, net of applicable income taxes. Equity securities with a readily determinable fair value are reported at fair value with net unrealized gains and losses recognized in the consolidated statements of income. None of the Company's investment securities have been classified as trading securities at September 30, 2018. Certain equity securities that do not have a readily determinable fair value are stated at cost, less impairment, adjusted for observable price changes in orderly transactions for identical or similar investments of the same issuer. These securities include restricted stock of the Federal Reserve Bank of New York (“Federal Reserve”), the Federal Home Loan Bank of New York and the Federal Home Loan Bank of Boston (collectively referred to as “FHLB”), as well as other equity securities. During the third quarter of 2018, the Company adjusted the carrying value of an equity security without a readily determinable fair value based on observable price changes for identical investments of the same issuer. This adjustment resulted in a $0.8 million unrealized gain on equity securities. Fair values for investment securities are based upon quoted market prices, where available. If quoted market prices are not available, fair values are based upon quoted market prices of comparable instruments, or a discounted cash flow model using market estimates of interest rates and volatility. The Company conducts an assessment of all securities in an unrealized loss An OTTI loss must be recognized for a debt security in an unrealized loss position if there is intent to sell the security or it is more likely than not the Company will be required to sell the security prior to recovery of its amortized cost basis. In this situation, the amount of loss recognized in income is equal to the difference between the fair value and the amortized cost basis of the security. Even if management does not have the intent, and it is not more likely than not that the Company will be required to sell the securities, an evaluation of the expected cash flows to be received is performed to determine if a credit loss has occurred. For debt securities, a critical component of the evaluation for OTTI is the identification of credit-impaired securities, where the Company does not expect to receive cash flows sufficient to recover the entire amortized cost basis of the security. In the event of a credit loss, only the amount of impairment associated with the credit loss would be recognized in income. The portion of the unrealized loss relating to other factors, such as liquidity conditions in the market or changes in market interest rates, is recorded in accumulated other comprehensive loss. The specific identification method is used in determining the realized gains and losses on sales of investment securities and OTTI charges. Premiums and discounts on securities are amortized and accreted, respectively, on the interest method basis over the period to maturity or estimated life of the related security. Purchases and sales of securities are recognized on a trade date basis. Revenue Recognition On January 1, 2018, the Company adopted ASU No. 2014-09 Revenue from Contracts with Customers (Topic 606) Topic 606 does not apply to revenue associated with financial instruments, including revenue from loans and securities. In addition, certain noninterest income streams such as fees associated with mortgage servicing rights, financial guarantees, derivatives, and certain credit card fees are also not in scope of the newly adopted guidance. Topic 606 is applicable to the Company’s noninterest revenue streams including its deposit related fees, electronic payment interchange fees, merchant income, trust, asset management and other wealth management revenues, insurance commissions and benefit plan services income. However, the recognition of these revenue streams did not change significantly upon adoption of Topic 606. Noninterest revenue streams in-scope of Topic 606 are discussed below. Deposit Service Fees Deposit service fees consist of account activity fees, monthly service fees, check orders, debit and credit card income, ATM fees, Merchant services income and other revenues from processing wire transfers, bill pay service, cashier’s checks and foreign exchange. Debit and credit card income is primarily comprised of interchange fees earned at the time the Company’s debit and credit cards are processed through card payment networks such as Visa. ATM fees are primarily generated when a Company cardholder uses a non-Company ATM or a non-Company cardholder uses a Company ATM. Merchant services income mainly represents fees charged to merchants to process their debit and credit card transactions, in addition to account management fees. The Company’s performance obligation for deposit service fees is generally satisfied, and the related revenue recognized, when the services are rendered or the transaction has been completed. Payment for deposit service fees is typically received at the time it is assessed through a direct charge to customers’ accounts or on a monthly basis. Deposit service fees revenue primarily relates to the Company’s Banking operating segment. Other Banking Services Other banking services consists of other recurring revenue streams such as commissions from sales of credit life insurance, safe deposit box rental fees, mortgage banking income, bank owned life insurance income and other miscellaneous revenue streams. Commissions from the sale of credit life insurance are recognized at the time of sale of the policies. Safe deposit box rental fees are charged to the customer on an annual basis and recognized upon receipt of payment. The Company determined that since rentals and renewals occur fairly consistently over time, revenue is recognized on a basis consistent with the duration of the performance obligation. Mortgage banking income and bank owned life insurance income are not within the scope of Topic 606. Other banking services revenue primarily relates to the Company’s Banking operating segment. Employee Benefit Services Employee benefit services income consists of revenue received from retirement plan services, collective investment fund services, fund administration, transfer agency, consulting and actuarial services. The Company’s performance obligation that relates to plan services are satisfied over time and the resulting fees are recognized monthly or quarterly, based upon the market value of the assets under management and the applicable fee rate or on a time expended basis. Payment is generally received a few days after month end or quarter end. The Company does not earn performance-based incentives. Transactional services such as consulting services, mailings, or other ad hoc services are provided to existing trust and asset management customers. The Company’s performance obligation for these transactional-based services is generally satisfied, and related revenue recognized, at a point in time (i.e., as incurred). Payment is received shortly after services are rendered. Employee benefit services revenue primarily relates to the Company’s Employee Benefit Services operating segment. Insurance Services Insurance services primarily consists of commissions received on insurance product sales and consulting services. The Company acts in the capacity of a broker or agent between the Company’s customer and the insurance carrier. The Company’s performance obligation related to insurance sales for both property and casualty insurance and employee benefit plans is generally satisfied upon the later of the issuance or effective date of the policy. The Company’s performance obligation related to consulting services is considered transactional in nature and is generally satisfied when the services have been completed and related revenue recognized at a point in time. Payment is received at the time services are rendered. The Company earns performance based incentives, commonly known as contingency payments, which usually are based on certain criteria established by the insurance carrier such as premium volume, growth and insured loss ratios. Contingent payments are accrued for based upon management’s expectations for the year. Commission expense associated with sales of insurance products is expensed as incurred. Insurance services revenue primarily relates to the Company’s All Other operating segment. Wealth Management Services Wealth management services income is primarily comprised of fees earned from the management and administration of trusts and other customer assets. The Company generally has two types of performance obligations related to these services. The Company’s performance obligation that relates to advisory and administration services are satisfied over time and the resulting fees are recognized monthly, based upon the market value of the assets under management and the applicable fee rate. Payment is generally received soon after month end or quarter end through a direct charge to customers’ accounts. The Company does not earn performance-based incentives. Transactional services such as tax return preparation services, purchases and sales of investments and insurance products are also available to existing trust and asset management customers. The Company’s performance obligation for these transactional-based services is generally satisfied, and related revenue recognized, at a point in time (i.e. as incurred). Payment is generally received on a monthly basis. Wealth management services revenue primarily relates to the Company’s All Other operating segment. Contract Balances A contract asset balance occurs when an entity performs a service for a customer before the customer pays consideration (resulting in a contract receivable) or before payment is due (resulting in a contract asset). A contract liability balance is an entity’s obligation to transfer a service to a customer for which the entity has already received payment (or payment is due) from the customer. The Company’s noninterest revenue streams are largely based on transactional activity, or standard month-end revenue accruals such as asset management fees based on month-end market values. Consideration is often received immediately or shortly after the Company satisfies its performance obligation and revenue is recognized. The Company does not typically enter into long-term revenue contracts with customers, and therefore, does not experience significant contract balances. As of September 30, 2018, $26.9 million of accounts receivable, including $7.9 million of unbilled fee revenue, and $2.9 million of unearned revenue was recorded in the Consolidated Statements of Condition. As of December 31, 2017, $29.8 million of accounts receivable, including $6.5 million of unbilled fee revenue, and $3.9 million of unearned revenue was recorded in the Consolidated Statements of Condition. Contract Acquisition Costs In connection with the adoption of Topic 606, an entity is required to capitalize, and subsequently amortize into expense, certain incremental costs of obtaining a contract with a customer if these costs are expected to be recovered. The incremental costs of obtaining a contract are those costs that an entity incurs to obtain a contract with a customer that it would not have incurred if the contract had not been obtained (for example, sales commission). The Company utilizes the practical expedient method which allows entities to immediately expense contract acquisition costs when the asset that would have resulted from capitalizing these costs would have been amortized in one year or less. Upon adoption of Topic 606, the Company did not capitalize any contract acquisition costs. Recently Adopted Accounting Pronouncements In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606) In January 2016, the FASB issued ASU 2016-01, Financial Instruments - Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities. The Company adopted this guidance on January 1, 2018. The impact of the adoption of this guidance resulted in the reclassification of $0.2 million of other comprehensive income to retained earnings. See the Consolidated Statements of Comprehensive Income and Consolidated Statement of Changes in Shareholders’ Equity. In August 2016, the FASB issued ASU No. 2016-15, Statement of Cash Flows (Topic 230) In March 2017, the FASB issued ASU No. 2017-07, Compensation – Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost. New Accounting Pronouncements In February 2016, the FASB issued ASU 2016-02, Leases (Topic 842) Topic 840, Leases In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments – Credit Losses (Topic 326) In January 2017, the FASB issued ASU No. 2017-04, Intangibles-Goodwill and Other (Topic 350) In August 2017, the FASB issued ASU No. 2017-12, Derivatives and Hedging (Topic 815): Targeted Improvements to Accounting for Hedging Activities.

INVESTMENT SECURITIES

INVESTMENT SECURITIES	9 Months Ended
	Sep. 30, 2018
INVESTMENT SECURITIES [Abstract]
INVESTMENT SECURITIES	NOTE D: INVESTMENT SECURITIES The amortized cost and estimated fair value of investment securities as of September 30, 2018 and December 31, 2017 are as follows: September 30, 2018 December 31, 2017 (000's omitted) Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Available-for-Sale Portfolio: U.S. Treasury and agency securities $ 2,039 , $ 0 $ 40,991 $ 1,998,095 $ 2,043,023 $ 15,886 $ 4,838 $ 2,054,071 Obligations of state and political subdivisions 473 ,0 5,250 2,933 475,365 514,949 14,064 57 528,956 Government agency mortgage-backed securities 369,970 1,297 13,204 358,063 358,180 3,121 3,763 357,538 Corporate debt securities 2,603 0 53 2,550 2,648 0 25 2,623 Government agency collateralized mortgage obligations 73,112 25 2,431 70,706 88,097 155 878 87,374 Marketable equity securities 0 0 0 0 251 275 0 526 Total available-for-sale portfolio $ 2,957,819 $ 6,572 $ 59,612 $ 2,904,779 $ 3,007,148 $ 33,501 $ 9,561 $ 3,031,088 Equity and other Securities: Equity securities, at fair value $ 251 $ 247 $ 0 $ 498 $ 0 $ 0 $ 0 $ 0 Federal Home Loan Bank common stock 6,343 0 0 6,343 9,896 0 0 9,896 Federal Reserve Bank common stock 30,690 0 0 30,690 30,690 0 0 30,690 Certificates of deposit 0 0 0 0 3,865 0 0 3,865 Other equity securities, at cost 4,997 750 0 5,747 5,840 0 0 5,840 Total equity and other securities $ 42 , $ 997 $ 0 $ 43,278 $ 50,291 $ 0 $ 0 $ 50,291 A summary of investment securities that have been in a continuous unrealized loss position is as follows: As of September 30, 2018 Less than 12 Months 12 Months or Longer Total (000's omitted) # Fair Value Gross Unrealized Losses # Fair Value Gross Unrealized Losses # Fair Value Gross Unrealized Losses Available-for-Sale Portfolio: U.S. Treasury and agency securities 50 $ 1,633,859 $ 30,625 32 $ 364,236 $ 10,366 82 $ 1,998,095 $ 40,991 Obligations of state and political subdivisions 333 171,781 2,619 9 5,913 314 342 177,694 2,933 Government agency mortgage-backed securities 89 128,752 3,783 136 178,871 9,421 225 307,623 13,204 Corporate debt securities 0 0 0 1 2,550 53 1 2,550 53 Government agency collateralized mortgage obligations 12 8,371 199 36 59,825 2,232 48 68,196 2,431 Total available-for-sale investment portfolio 484 $ 1,942 , $ 37,226 214 $ 611,395 $ 22,386 698 $ 2,554,158 $ 59,612 As of December 31, 2017 Less than 12 Months 12 Months or Longer Total (000's omitted) # Fair Value Gross Unrealized Losses # Fair Value Gross Unrealized Losses # Fair Value Gross Unrealized Losses Available-for-Sale Portfolio: U.S. Treasury and agency securities 44 $ 699,709 $ 4,838 0 $ 0 $ 0 44 $ 699,709 $ 4,838 Obligations of state and political subdivisions 45 23,432 57 0 0 0 45 23,432 57 Government agency mortgage-backed securities 120 185,716 1,433 55 75,712 2,330 175 261,428 3,763 Corporate debt securities 1 2,623 25 0 0 0 1 2,623 25 Government agency collateralized mortgage obligations 39 80,041 878 1 1 0 40 80,042 878 Total available-for-sale investment portfolio 249 $ 991,521 $ 7,231 56 $ 75,713 $ 2,330 305 $ 1,067,234 $ 9,561 The unrealized losses reported pertaining to securities issued by the U.S. government and its sponsored entities, include treasuries, agencies, and mortgage-backed securities issued by Ginnie Mae, Fannie Mae, and Freddie Mac, which are currently rated AAA by Moody’s Investor Services, AA+ by Standard & Poor’s and are guaranteed by the U.S. government. The majority of the obligations of state and political subdivisions and corporations carry a credit rating of A or better. Additionally, a majority of the obligations of state and political subdivisions carry a secondary level of credit enhancement. The Company does not intend to sell these securities, nor is it more likely than not that the Company will be required to sell these securities prior to recovery of the amortized cost. The unrealized losses in the portfolios are primarily attributable to changes in interest rates. As such, management does not believe any individual unrealized loss as of September 30, 2018 represents OTTI. The amortized cost and estimated fair value of debt securities at September 30, 2018, by contractual maturity, are shown below. Expected maturities will differ from contractual maturities because borrowers may have the right to call or prepay obligations with or without call or prepayment penalties. Securities not due at a single maturity date are shown separately. Available-for-Sale (000's omitted) Amortized Cost Fair Value Due in one year or less $ 61,112 $ 60,985 Due after one through five years 2,020,525 1,985,501 Due after five years through ten years 274,222 270,449 Due after ten years 158,878 159,075 Subtotal 2,514,737 2,476,010 Government agency mortgage-backed securities 369,970 358,063 Government agency collateralized mortgage obligations 73,112 70,706 Total $ 2,957,819 $ 2,904,779 As of September 30, 2018, $289.0 million of U.S. Treasury securities were pledged as collateral for securities sold under agreement to repurchase. All securities sold under agreement to repurchase as of September 30, 2018 have an overnight and continuous maturity.

LOANS

LOANS	9 Months Ended
	Sep. 30, 2018
LOANS [Abstract]
LOANS	NOTE E: LOANS The segments of the Company’s loan portfolio are disaggregated into the following classes that allow management to monitor risk and performance: · Consumer mortgages consist primarily of fixed rate residential instruments, typically 10 – 30 years in contractual term, secured by first liens on real property. · Business lending is comprised of general purpose commercial and industrial loans including, but not limited to, municipal lending, agricultural-related and dealer floor plans, as well as mortgages on commercial properties. · Consumer indirect consists primarily of installment loans originated through selected dealerships and are secured by automobiles, marine and other recreational vehicles. · Consumer direct consists of all other loans to consumers such as personal installment loans and lines of credit. · Home equity products are consumer purpose installment loans or lines of credit most often secured by a first or second lien position on residential real estate with terms up to 30 years. The balances of these classes are summarized as follows: (000's omitted) September 30, 2018 December 31, 2017 Business lending $ 2,403,624 $ 2,424,223 Consumer mortgage 2,220,022 2,220,298 Consumer indirect 1,098,943 1,011,978 Consumer direct 184,349 179,929 Home equity 393,950 420,329 Gross loans, including deferred origination costs 6,300,888 6,256,757 Allowance for loan losses (50,133 ) (47,583 ) Loans, net of allowance for loan losses $ 6,250,755 $ 6,209,174 The outstanding balance related to credit impaired acquired loans was $7.8 million and $13.4 million at September 30, 2018 and December 31, 2017, respectively. The changes in the accretable discount related to the credit impaired acquired loans are as follows: (000’s omitted) Balance at December 31, 2017 $ 976 Accretion recognized, year-to-date (722 ) Net reclassification between accretable and non-accretable 239 Balance at September 3 0 $ 493 Credit Quality Management monitors the credit quality of its loan portfolio on an ongoing basis. Measurement of delinquency and past due status are based on the contractual terms of each loan. Past due loans are reviewed on a monthly basis to identify loans for non-accrual status. The following is an aged analysis of the Company’s past due loans, by class as of September 30, 2018: Legacy Loans (000’s omitted) Past Due 30 – 89 Days 90+ Days Past Due and Still Accruing Nonaccrual Total Past Due Current Total Loans Business lending $ 5,751 $ 355 $ 3,335 $ 9,441 $ 1,573,366 $ 1,582,807 Consumer mortgage 10,189 1,767 9,915 21,871 1,793,227 1,815,098 Consumer indirect 12,408 175 0 12,583 1,073,607 1,086,190 Consumer direct 1,510 20 0 1,530 179,399 180,929 Home equity 1,191 371 1,433 2,995 311,817 314,812 Total $ 31,049 $ 2,688 $ 14,683 $ 48,420 $ 4,931,416 $ 4,979,836 Acquired Loans (000’s omitted) Past Due 30 – 89 Days 90+ Days Past Due and Still Accruing Nonaccrual Total Past Due Acquired Impaired (1) Current Total Loans Business lending $ 1,134 $ 0 $ 3,711 $ 4,845 $ 5,851 $ 810,121 $ 820,817 Consumer mortgage 977 215 2,438 3,630 0 401,294 404,924 Consumer indirect 100 34 0 134 0 12,619 12,753 Consumer direct 74 0 0 74 0 3,346 3,420 Home equity 618 14 1,150 1,782 0 77,356 79,138 Total $ 2,903 $ 263 $ 7,299 $ 10,465 $ 5,851 $ 1,304,736 $ 1,321,052 (1) Acquired impaired loans were not classified as nonperforming assets as the loans are considered to be performing under ASC 310-30. As a result interest income, through the accretion of the difference between the carrying amount of the loans and the expected cashflows, is being recognized on all acquired impaired loans. The following is an aged analysis of the Company’s past due loans by class as of December 31, 2017: Legacy Loans (000’s omitted) Past Due 30 – 89 Days 90+ Days Past Due and Still Accruing Nonaccrual Total Past Due Current Total Loans Business lending $ 2,283 $ 571 $ 3,944 $ 6,798 $ 1,369,801 $ 1,376,599 Consumer mortgage 13,564 1,500 10,722 25,786 1,728,823 1,754,609 Consumer indirect 14,197 295 0 14,492 977,344 991,836 Consumer direct 1,875 48 0 1,923 172,556 174,479 Home equity 1,116 94 1,354 2,564 319,576 322,140 Total $ 33,035 $ 2,508 $ 16,020 $ 51,563 $ 4,568,100 $ 4,619,663 Acquired Loans (000’s omitted) Past Due 30 – 89 Days 90+ Days Past Due and Still Accruing Nonaccrual Total Past Due Acquired Impaired (1) Current Total Loans Business lending $ 4,661 $ 0 $ 4,328 $ 8,989 $ 10,115 $ 1,028,520 $ 1,047,624 Consumer mortgage 2,603 26 3,066 5,695 0 459,994 465,689 Consumer indirect 245 8 0 253 0 19,889 20,142 Consumer direct 100 0 0 100 0 5,350 5,450 Home equity 634 170 1,326 2,130 0 96,059 98,189 Total $ 8,243 $ 204 $ 8,720 $ 17,167 $ 10,115 $ 1,609,812 $ 1,637,094 (1) Acquired impaired loans were not classified as nonperforming assets as the loans are considered to be performing under ASC 310-30. As a result interest income, through the accretion of the difference between the carrying amount of the loans and the expected cashflows, is being recognized on all acquired impaired loans. The Company uses several credit quality indicators to assess credit risk in an ongoing manner. The Company’s primary credit quality indicator for its business lending portfolio is an internal credit risk rating system that categorizes loans as “pass”, “special mention”, “classified”, or “doubtful”. Credit risk ratings are applied individually to those classes of loans that have significant or unique credit characteristics that benefit from a case-by-case evaluation. In general, the following are the definitions of the Company’s credit quality indicators: Pass The condition of the borrower and the performance of the loans are satisfactory or better. Special Mention The condition of the borrower has deteriorated although the loan performs as agreed. Classified The condition of the borrower has significantly deteriorated and the performance of the loan could further deteriorate, if deficiencies are not corrected. Doubtful The condition of the borrower has deteriorated to the point that collection of the balance is improbable based on current facts and conditions. The following table shows the amount of business lending loans by credit quality category: September 30, 2018 December 31, 2017 (000’s omitted) Legacy Acquired Total Legacy Acquired Total Pass $ 1,394,290 $ 740,329 $ 2,134,619 $ 1,170,156 $ 963,981 $ 2,134,137 Special mention 112,777 47,773 160,550 129,076 37,321 166,397 Classified 75,740 25,285 101,025 77,367 34,628 111,995 Doubtful 0 1,579 1,579 0 1,579 1,579 Acquired impaired 0 5,851 5,851 0 10,115 10,115 Total $ 1,582,807 $ 820,817 $ 2,403,624 $ 1,376,599 $ 1,047,624 $ 2,424,223 All other loans are underwritten and structured using standardized criteria and characteristics, primarily payment performance, and are normally risk rated and monitored collectively on a monthly basis. These are typically loans to individuals in the consumer categories and are delineated as either performing or nonperforming. Performing loans include loans classified as current as well as those classified as 30 - 89 days past due. Nonperforming loans include 90+ days past due and still accruing and nonaccrual loans. The following table details the balances in all other loan categories at September 30, 2018: Legacy Loans (000’s omitted) Consumer Mortgage Consumer Indirect Consumer Direct Home Equity Total Performing $ 1,803,416 $ 1,086,015 $ 180,909 $ 313,008 $ 3,383,348 Nonperforming 11,682 175 20 1,804 13,681 Total $ 1,815,098 $ 1,086,190 $ 180,929 $ 314,812 $ 3,397,029 Acquired Loans (000’s omitted) Consumer Mortgage Consumer Indirect Consumer Direct Home Equity Total Performing $ 402,271 $ 12,719 $ 3,420 $ 77,974 $ 496,384 Nonperforming 2,653 34 0 1,164 3,851 Total $ 404,924 $ 12,753 $ 3,420 $ 79,138 $ 500,235 The following table details the balances in all other loan categories at December 31, 2017: Legacy Loans (000’s omitted) Consumer Mortgage Consumer Indirect Consumer Direct Home Equity Total Performing $ 1,742,387 $ 991,541 $ 174,431 $ 320,692 $ 3,229,051 Nonperforming 12,222 295 48 1,448 14,013 Total $ 1,754,609 $ 991,836 $ 174,479 $ 322,140 $ 3,243,064 Acquired Loans (000’s omitted) Consumer Mortgage Consumer Indirect Consumer Direct Home Equity Total Performing $ 462,597 $ 20,134 $ 5,450 $ 96,693 $ 584,874 Nonperforming 3,092 8 0 1,496 4,596 Total $ 465,689 $ 20,142 $ 5,450 $ 98,189 $ 589,470 All loan classes are collectively evaluated for impairment except business lending. A summary of individually evaluated impaired loans as of September 30, 2018 and December 31, 2017 follows: (000’s omitted) September 30, 2018 December 31, 2017 Loans with allowance allocation $ 3,956 $ 5,125 Loans without allowance allocation 1,151 884 Carrying balance 5,107 6,009 Contractual balance 9,688 9,165 Specifically allocated allowance 956 804 In the course of working with borrowers, the Company may choose to restructure the contractual terms of certain loans. In this scenario, the Company attempts to work-out an alternative payment schedule with the borrower in order to optimize collectability of the loan. Any loans that are modified are reviewed by the Company to identify if a troubled debt restructuring (“TDR”) has occurred, which is when, for economic or legal reasons related to a borrower’s financial difficulties, the Company grants a concession to the borrower that it would not otherwise consider. Terms may be modified to fit the ability of the borrower to repay in line with its current financial standing and the restructuring of the loan may include the transfer of assets from the borrower to satisfy the debt, a modification of loan terms, or a combination of the two. In accordance with the clarified guidance issued by the Office of the Comptroller of the Currency (“OCC”), loans that have been discharged in Chapter 7 bankruptcy but not reaffirmed by the borrower, are classified as TDRs, irrespective of payment history or delinquency status, even if the repayment terms for the loan have not been otherwise modified. The Company’s lien position against the underlying collateral remains unchanged. Pursuant to that guidance, the Company records a charge-off equal to any portion of the carrying value that exceeds the net realizable value of the collateral. The amount of loss incurred in the three and nine months ended September 30, 2018 and 2017 was immaterial. TDRs that are less than $0.5 million are collectively included in the general loan loss allocation and the qualitative review. TDRs that are commercial loans and greater than $0.5 million are individually evaluated for impairment, and if necessary, a specific allocation of the allowance for loan losses is provided. As a result, the determination of the amount of allowance for loan losses related to TDRs is the same as detailed in the critical accounting policies. Information regarding TDRs as of September 30, 2018 and December 31, 2017 is as follows: September 30, 2018 December 31, 2017 (000’s omitted) Nonaccrual Accruing Total Nonaccrual Accruing Total # Amount # Amount # Amount # Amount # Amount # Amount Business lending 5 $ 165 3 $ 319 8 $ 484 8 $ 218 7 $ 501 15 $ 719 Consumer mortgage 45 2,000 46 1,783 91 3,783 51 2,265 44 1,750 95 4,015 Consumer indirect 0 0 76 814 76 814 0 0 71 883 71 883 Consumer direct 0 0 22 70 22 70 0 0 25 69 25 69 Home equity 12 215 8 279 20 494 13 245 7 204 20 449 Total 62 $ 2,380 155 $ 3,265 217 $ 5,645 72 $ 2,728 154 $ 3,407 226 $ 6,135 The following table presents information related to loans modified in a TDR during the three months and nine months ended September 30, 2018 and 2017. Of the loans noted in the table below, all loans for the three months and nine months ended September 30, 2018 and 2017 were modified due to a Chapter 7 bankruptcy as described previously. The financial effects of these restructurings were immaterial. Three Months Ended September 30, 2018 Three Months Ended September 30, 2017 (000’s omitted) Number of loans modified Outstanding Balance Number of loans modified Outstanding Balance Business lending 0 $ 0 1 $ 51 Consumer mortgage 4 195 8 540 Consumer indirect 14 117 8 181 Consumer direct 2 10 1 1 Home equity 1 0 1 8 Total 21 $ 322 19 $ 781 Nine Months Ended September 30, 2018 Nine Months Ended September 30, 2017 (000’s omitted) Number of loans modified Outstanding Balance Number of loans modified Outstanding Balance Business lending 1 $ 93 4 $ 414 Consumer mortgage 7 407 15 1,040 Consumer indirect 24 176 22 323 Consumer direct 5 21 4 7 Home equity 2 85 3 106 Total 39 $ 782 48 $ 1,890 Allowance for Loan Losses The allowance for loan losses is general in nature and is available to absorb losses from any loan type despite the analysis below. The following presents by class the activity in the allowance for loan losses: Three Months Ended (000’s omitted) Business Lending Consumer Mortgage Consumer Indirect Consumer Direct Home Equity Unallocated Acquired Impaired Total Beginning balance $ 18,439 $ 10,473 $ 14,424 $ 3,164 $ 2,015 $ 1,070 $ 33 $ 49,618 Charge-offs (73 ) (144 ) (2,364 ) (465 ) (221 ) 0 0 (3,267 ) Recoveries 93 46 1,190 223 15 0 0 1,567 Provision 321 (205 ) 1,719 299 225 (159 ) 15 2,215 Ending balance $ 18,780 $ 10,170 $ 14,969 $ 3,221 $ 2,034 $ 911 $ 48 $ 50,133 Three Months Ended (000’s omitted) Business Lending Consumer Mortgage Consumer Indirect Consumer Direct Home Equity Unallocated Acquired Impaired Total Beginning balance $ 17,230 $ 10,197 $ 13,918 $ 2,945 $ 2,242 $ 856 $ 63 $ 47,451 Charge-offs (124 ) (198 ) (2,328 ) (574 ) 0 0 0 (3,224 ) Recoveries 127 24 1,058 221 12 0 0 1,442 Provision 399 280 1,130 426 (52 ) 142 (11 ) 2,314 Ending balance $ 17,632 $ 10,303 $ 13,778 $ 3,018 $ 2,202 $ 998 $ 52 $ 47,983 Nine Months Ended (000’s omitted) Business Lending Consumer Mortgage Consumer Indirect Consumer Direct Home Equity Unallocated Acquired Impaired Total Beginning balance $ 17,257 $ 10,465 $ 13,468 $ 3,039 $ 2,107 $ 1,100 $ 147 $ 47,583 Charge-offs (2,000 ) (588 ) (6,031 ) (1,324 ) (325 ) 0 (368 ) (10,636 ) Recoveries 404 109 3,688 612 31 0 0 4,844 Provision 3,119 184 3,844 894 221 (189 ) 269 8,342 Ending balance $ 18,780 $ 10,170 $ 14,969 $ 3,221 $ 2,034 $ 911 $ 48 $ 50,133 Nine Months Ended (000’s omitted) Business Lending Consumer Mortgage Consumer Indirect Consumer Direct Home Equity Unallocated Acquired Impaired Total Beginning balance $ 17,220 $ 10,094 $ 13,782 $ 2,979 $ 2,399 $ 651 $ 108 $ 47,233 Charge-offs (1,062 ) (541 ) (5,969 ) (1,463 ) (228 ) 0 (184 ) (9,447 ) Recoveries 481 42 3,379 648 44 0 0 4,594 Provision 993 708 2,586 854 (13 ) 347 128 5,603 Ending balance $ 17,632 $ 10,303 $ 13,778 $ 3,018 $ 2,202 $ 998 $ 52 $ 47,983

GOODWILL AND IDENTIFIABLE INTAN

GOODWILL AND IDENTIFIABLE INTANGIBLE ASSETS	9 Months Ended
	Sep. 30, 2018
GOODWILL AND IDENTIFIABLE INTANGIBLE ASSETS [Abstract]
GOODWILL AND IDENTIFIABLE INTANGIBLE ASSETS	NOTE F: GOODWILL AND IDENTIFIABLE INTANGIBLE ASSETS The gross carrying amount and accumulated amortization for each type of identifiable intangible asset are as follows: September 30, 2018 December 31, 2017 (000's omitted) Gross Carrying Amount Accumulated Amortization Net Carrying Amount Gross Carrying Amount Accumulated Amortization Net Carrying Amount Amortizing intangible assets: Core deposit intangibles $ 62,902 $ (42,790 ) $ 20,112 $ 62,902 $ (37,877 ) $ 25,025 Other intangibles 87,616 (29,507 ) 58,109 86,535 (20,902 ) 65,633 Total amortizing intangibles $ 150,518 $ (72,297 ) $ 78,221 $ 149,437 $ (58,779 ) $ 90,658 The estimated aggregate amortization expense for each of the five succeeding fiscal years ended December 31 is as follows: (000's omitted) Oct - Dec 2018 $ 4,375 2019 15,296 2020 12,722 2021 10,853 2022 9,317 Thereafter 25,658 Total $ 78,221 Shown below are the components of the Company’s goodwill at December 31, 2017 and September 30, 2018: (000’s omitted) December 31, 2017 Activity September 30, 2018 Goodwill $ 739,254 $ (951 ) $ 738,303 Accumulated impairment (4,824 ) 0 (4,824 ) Goodwill, net $ 734,430 $ (951 ) $ 733,479

MANDATORILY REDEEMABLE PREFERRE

MANDATORILY REDEEMABLE PREFERRED SECURITIES	9 Months Ended
	Sep. 30, 2018
MANDATORILY REDEEMABLE PREFERRED SECURITIES [Abstract]
MANDATORILY REDEEMABLE PREFERRED SECURITIES	NOTE G: MANDATORILY REDEEMABLE PREFERRED SECURITIES As of September 30, 2018, the Company sponsors two business trusts, Community Capital Trust IV (“CCT IV”) and MBVT Statutory Trust I (“MBVT I”), of which 100% of the common stock is owned by the Company. The common stock of MBVT Statutory Trust I was acquired in the Merchants acquisition. The Company previously sponsored Community Statutory Trust III (“CST III”) until July 31, 2018 when the Company exercised its right to redeem all of the CST III debentures and associated preferred securities for a total of $25.2 million. The trusts were formed for the purpose of issuing company-obligated mandatorily redeemable preferred securities to third-party investors and investing the proceeds from the sale of such preferred securities solely in junior subordinated debt securities of the Company. The debentures held by each trust are the sole assets of such trust. Distributions on the preferred securities issued by each trust are payable quarterly at a rate per annum equal to the interest rate being earned by the trust on the debentures held by that trust and are recorded as interest expense in the consolidated financial statements. The preferred securities are subject to mandatory redemption, in whole or in part, upon repayment of the debentures. The Company has entered into agreements which, taken collectively, fully and unconditionally guarantee the preferred securities subject to the terms of each of the guarantees. The terms of the preferred securities of each trust are as follows: Trust Issuance Date Par Amount Interest Rate Maturity Date Call Price CCT IV 12/8/2006 $75.0 million 3 month LIBOR plus 1.65% (3.98%) 12/15/2036 Par MBVT I 12/15/2004 $20.6 million 3 month LIBOR plus 1.95% (4.28%) 12/31/2034 Par

BENEFIT PLANS

BENEFIT PLANS	9 Months Ended
	Sep. 30, 2018
BENEFIT PLANS [Abstract]
BENEFIT PLANS	NOTE H: BENEFIT PLANS The Company provides a qualified defined benefit pension to eligible employees and retirees, other post-retirement health and life insurance benefits to certain retirees, an unfunded supplemental pension plan for certain key executives, and an unfunded stock balance plan for certain of its nonemployee directors. The Company accrues for the estimated cost of these benefits through charges to expense during the years that employees earn these benefits. Effective May 12, 2017, the Merchants Bank Pension Plan was merged into the Community Bank System, Inc. Pension Plan and the combined plan was revalued resulting in an additional unamortized actuarial gain of approximately $1.9 million, due primarily to a gain on plan assets that was partially offset by a decrease in the discount rate from 4.50% to 4.40% as of the valuation date. Effective June 1, 2018, the Company adopted the Community Bank System, Inc. Restoration Plan (“Restoration Plan”). The Restoration Plan is a non-qualified deferred compensation plan for certain employees whose benefits under tax-qualified retirement plans are restricted by the Internal Revenue Code Section 401(a)(17) limitation on compensation. Adoption of the plan resulted in an unfunded initial projected benefit obligation of approximately $0.8 million that will be amortized over the average expected future years of service of active plan participants. The net periodic benefit cost for the three and nine months ended September 30, 2018 and 2017 is as follows: Pension Benefits Post-retirement Benefits Three Months Ended September 30, Nine Months Ended September 30, Three Months Ended September 30, Nine Months Ended September 30, (000's omitted) 2018 2017 2018 2017 2018 2017 2018 2017 Service cost $ 1,154 $ 1,037 $ 3,396 $ 3,143 $ 0 $ 0 $ 0 $ 0 Interest cost 1,422 1,453 4,251 4,265 18 19 52 57 Expected return on plan assets (3,705 ) (3,448 ) (11,115 ) (9,977 ) 0 0 0 0 Amortization of unrecognized net loss 299 148 895 619 5 2 15 6 Amortization of prior service cost (60 ) 13 (225 ) 43 (45 ) (45 ) (134 ) (134 ) Net periodic benefit cost (income) $ (890 ) $ (797 ) $ (2,798 ) $ (1,907 ) $ (22 ) $ (24 ) $ (67 ) $ (71 )

EARNINGS PER SHARE

EARNINGS PER SHARE	9 Months Ended
	Sep. 30, 2018
EARNINGS PER SHARE [Abstract]
EARNINGS PER SHARE	NOTE I: EARNINGS PER SHARE The two class method is used in the calculations of basic and diluted earnings per share. Under the two class method, earnings available to common shareholders for the period are allocated between common shareholders and participating securities according to dividends declared and participation rights in undistributed earnings. The Company has determined that all of its outstanding non-vested stock awards are participating securities as of September 30, 2018. Basic earnings per share are computed based on the weighted-average of the common shares outstanding for the period. Diluted earnings per share are based on the weighted-average of the shares outstanding and the assumed exercise of stock options during the year. The dilutive effect of options is calculated using the treasury stock method of accounting. The treasury stock method determines the number of common shares that would be outstanding if all the dilutive options (those where the average market price is greater than the exercise price) were exercised and the proceeds were used to repurchase common shares in the open market at the average market price for the applicable time period. There were approximately 0.4 million weighted-average anti-dilutive stock options outstanding for the three months and nine months ended September 30, 2018, compared to 0.2 million weighted-average anti-dilutive stock options outstanding for the three months ended September 30, 2017, and 0.1 million weighted-average anti-dilutive stock options outstanding for the nine months ended September 30, 2017 that were not included in the computation below. The following is a reconciliation of basic to diluted earnings per share for the three and nine months ended September 30, 2018 and 2017: Three Months Ended September 30, Nine Months Ended September 30, (000's omitted, except per share data) 2018 2017 2018 2017 Net income $ 43,106 $ 35,243 $ 127,818 $ 78,691 Income attributable to unvested stock-based compensation awards (191 ) (164 ) (563 ) (387 ) Income available to common shareholders $ 42,915 $ 35,079 $ 127,255 $ 78,304 Weighted-average common shares outstanding – basic 51,250 50,703 51,108 48,189 Basic earnings per share $ 0.84 $ 0.69 $ 2.49 $ 1.62 Net income $ 43,106 $ 35,243 $ 127,818 $ 78,691 Income attributable to unvested stock-based compensation awards (191 ) (164 ) (563 ) (387 ) Income available to common shareholders $ 42,915 $ 35,079 $ 127,255 $ 78,304 Weighted-average common shares outstanding – basic 51,250 50,703 51,108 48,189 Assumed exercise of stock options 608 585 590 640 Weighted-average common shares outstanding – diluted 51,858 51,288 51,698 48,829 Diluted earnings per share $ 0.83 $ 0.68 $ 2.46 $ 1.60 Stock Repurchase Program At its December 2017 meeting, the Company’s Board of Directors (the “Board”) approved a stock repurchase program authorizing the repurchase of up to 2.5 million shares of the Company’s common stock in accordance with securities laws and regulations, through December 31, 2018. Any repurchased shares will be used for general corporate purposes, including those related to stock plan activities. The timing and extent of repurchases will depend on market conditions and other corporate considerations as determined at the Company’s discretion. The Company did not repurchase any shares under the authorized plan during the first nine months of 2018.

COMMITMENTS, CONTINGENT LIABILI

COMMITMENTS, CONTINGENT LIABILITIES AND RESTRICTIONS	9 Months Ended
	Sep. 30, 2018
COMMITMENTS, CONTINGENT LIABILITIES AND RESTRICTIONS [Abstract]
COMMITMENTS, CONTINGENT LIABILITIES AND RESTRICTIONS	NOTE J: COMMITMENTS, CONTINGENT LIABILITIES AND RESTRICTIONS 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 consist primarily of commitments to extend credit and standby letters of credit. Commitments to extend credit are agreements to lend to customers, generally having fixed expiration dates or other termination clauses that may require payment of a fee. These commitments consist principally of unused commercial and consumer credit lines. Standby letters of credit generally are contingent upon the failure of the customer to perform according to the terms of an underlying contract with a third party. The credit risks associated with commitments to extend credit and standby letters of credit are essentially the same as that involved with extending loans to customers and are subject to the Company’s normal credit policies. Collateral may be obtained based on management’s assessment of the customer’s creditworthiness. The fair value of the standby letters of credit is immaterial for disclosure. The contract amounts of commitments and contingencies are as follows: (000's omitted) September 30, 2018 December 31, 2017 Commitments to extend credit $ 1,097,509 $ 1,080,004 Standby letters of credit 32,160 23,782 Total $ 1,129,669 $ 1,103,786 The Company and its subsidiaries are subject in the normal course of business to various pending and threatened legal proceedings in which claims for monetary damages are asserted. As of September 30, 2018, management, after consultation with legal counsel, does not anticipate that the aggregate ultimate liability arising out of litigation pending or threatened against the Company or its subsidiaries will be material to the Company’s consolidated financial position. On at least a quarterly basis, the Company assesses its liabilities and contingencies in connection with such legal proceedings. For those matters where it is probable that the Company will incur losses and the amounts of the losses can be reasonably estimated, the Company records an expense and corresponding liability in its consolidated financial statements. To the extent the pending or threatened litigation could result in exposure in excess of that liability, the amount of such excess is not currently estimable. The range of reasonably possible losses for matters where an exposure is not currently estimable or considered probable, beyond the existing recorded liabilities, is between $0 and $1 million in the aggregate. Although the Company does not believe that the outcome of pending litigation will be material to the Company’s consolidated financial position, it cannot rule out the possibility that such outcomes will be material to the consolidated results of operations for a particular reporting period in the future.

FAIR VALUE

FAIR VALUE	9 Months Ended
	Sep. 30, 2018
FAIR VALUE [Abstract]
FAIR VALUE	NOTE K: FAIR VALUE Accounting standards establish a framework for measuring fair value and require certain disclosures about such fair value instruments. It defines fair value as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date (i.e. exit price). Inputs used to measure fair value are classified into the following hierarchy: · Level 1 - Quoted prices in active markets for identical assets or liabilities. · Level 2 - Quoted prices in active markets for similar assets or liabilities, or quoted prices for identical or similar assets or liabilities in markets that are not active, or inputs other than quoted prices that are observable for the asset or liability. · Level 3 - Significant valuation assumptions not readily observable in a market. A financial instrument’s categorization within the valuation hierarchy is based upon the lowest level of input that is significant to the fair value measurement. The following tables set forth the Company’s financial assets and liabilities that were accounted for at fair value on a recurring basis. There were no transfers between any of the levels for the periods presented. September 30, 2018 (000's omitted) Level 1 Level 2 Level 3 Total Fair Value Available-for-sale investment securities: U.S. Treasury and agency securities $ 1,867,144 $ 130,951 $ 0 $ 1,998,095 Obligations of state and political subdivisions 0 475,365 0 475,365 Government agency mortgage-backed securities 0 358,063 0 358,063 Corporate debt securities 0 2,550 0 2,550 Government agency collateralized mortgage obligations 0 70,706 0 70,706 Total available-for-sale investment securities 1,867,144 1,037,635 0 2,904,779 Equity securities 498 0 0 498 Mortgage loans held for sale 0 0 0 0 Commitments to originate real estate loans for sale 0 0 9 9 Forward sales commitments 0 9 0 9 Interest rate swap agreements asset 0 1,306 0 1,306 Interest rate swap agreements liability 0 (1,360 ) 0 (1,360 ) Total $ 1,867,642 $ 1,037,590 $ 9 $ 2,905,241 December 31, 2017 (000's omitted) Level 1 Level 2 Level 3 Total Fair Value Available-for-sale investment securities: U.S. Treasury and agency securities $ 1,909,290 $ 144,781 $ 0 $ 2,054,071 Obligations of state and political subdivisions 0 528,956 0 528,956 Government agency mortgage-backed securities 0 357,538 0 357,538 Corporate debt securities 0 2,623 0 2,623 Government agency collateralized mortgage obligations 0 87,374 0 87,374 Marketable equity securities 526 0 0 526 Total available-for-sale investment securities 1,909,816 1,121,272 0 3,031,088 Mortgage loans held for sale 0 461 0 461 Commitments to originate real estate loans for sale 0 0 89 89 Forward sales commitments 0 4 0 4 Interest rate swap agreements asset 0 1,064 0 1,064 Interest rate swap agreements liability 0 (904 ) 0 (904 ) Total $ 1,909,816 $ 1,121,897 $ 89 $ 3,031,802 The valuation techniques used to measure fair value for the items in the table above are as follows: · Available-for-sale investment securities and equity securities – The fair values of available-for-sale investment securities and equity securities are based upon quoted prices, if available. If quoted prices are not available, fair values are measured using quoted market prices for similar securities or model-based valuation techniques. Level 1 securities include U.S. Treasury obligations and equity securities that are traded by dealers or brokers in active over-the-counter markets. Level 2 securities include U.S. agency securities, mortgage-backed securities issued by government-sponsored entities, municipal securities and corporate debt securities that are valued by reference to prices for similar securities or through model-based techniques in which all significant inputs, such as reported trades, trade execution data, LIBOR swap yield curve, market prepayment speeds, credit information, market spreads, and security’s terms and conditions, are observable. See Note D for further disclosure of the fair value of investment securities. · Mortgage loans held for sale – The Company has elected to value loans held for sale at fair value in order to more closely match the gains and losses associated with loans held for sale with the gains and losses on forward sales contracts. Accordingly, the impact on the valuation will be recognized in the Company’s consolidated statements of income. All mortgage loans held for sale are current and in performing status. The fair value of mortgage loans held for sale is determined using quoted secondary-market prices of loans with similar characteristics and, as such, has been classified as a Level 2 valuation. There were no mortgage loans held for sale at September 30, 2018. The unrealized gain on mortgage loans held for sale was recognized in other banking services revenues in the consolidated statements of income and is immaterial. · Forward sales commitments – The Company enters into forward sales commitments to sell certain residential real estate loans. Such commitments are considered to be derivative financial instruments and, therefore, are carried at estimated fair value in the other asset or other liability section of the consolidated statement of condition. The fair value of these forward sales commitments is primarily measured by obtaining pricing from certain government-sponsored entities and reflects the underlying price the entity would pay the Company for an immediate sale on these mortgages. As such, these instruments are classified as Level 2 in the fair value hierarchy. · Commitments to originate real estate loans for sale – The Company enters into various commitments to originate residential real estate loans for sale. Such commitments are considered to be derivative financial instruments and, therefore, are carried at estimated fair value in the other asset or other liability section of the consolidated statement of condition. The estimated fair value of these commitments is determined using quoted secondary market prices obtained from certain government-sponsored entities. Additionally, accounting guidance requires the expected net future cash flows related to the associated servicing of the loan to be included in the fair value measurement of the derivative. The expected net future cash flows are based on a valuation model that calculates the present value of estimated net servicing income. The valuation model incorporates assumptions that market participants would use in estimating future net servicing income. Such assumptions include estimates of the cost of servicing loans, appropriate discount rate and prepayment speeds. The determination of expected net cash flows is considered a significant unobservable input contributing to the Level 3 classification of commitments to originate real estate loans for sale. · Interest rate swaps – The interest rate swaps are reported at their fair value utilizing Level 2 inputs from third parties. The fair value of the interest rate swaps are determined using prices obtained from a third party advisor. The fair value measurement of the interest rate swap is determined by netting the discounted future fixed cash payments and the discounted expected variable cash receipts. The variable cash receipts are based on the expectation of future interest rates derived from observed market interest rate curves. The changes in Level 3 assets measured at fair value on a recurring basis are immaterial. The fair value information of assets and liabilities measured on a non-recurring basis presented below is not as of the period-end, but rather as of the date the fair value adjustment was recorded closest to the date presented. September 30, 2018 December 31, 2017 (000's omitted) Level 1 Level 2 Level 3 Total Fair Value Level 1 Level 2 Level 3 Total Fair Value Other real estate owned $ 0 $ 0 $ 1,142 $ 1,142 $ 0 $ 0 $ 1,915 $ 1,915 Loans are generally not recorded at fair value on a recurring basis. Periodically, the Company records nonrecurring adjustments to the carrying value of loans based on fair value measurements for partial charge-offs of the uncollectible portions of those loans. Nonrecurring adjustments also include certain impairment amounts for collateral-dependent loans calculated when establishing the allowance for loan 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 amount does not necessarily represent the fair value of the loan. Real estate collateral is typically valued using independent appraisals or other indications of value based on recent comparable sales of similar properties or assumptions generally observable in the marketplace, adjusted for non-observable inputs. Thus, the resulting nonrecurring fair value measurements are generally classified as Level 3. Estimates of fair value used for other collateral supporting commercial loans generally are based on assumptions not observable in the marketplace and, therefore, such valuations classify as Level 3. Other real estate owned (“OREO”) is valued at the time the loan is foreclosed upon and the asset is transferred to OREO. The value is based primarily on third party appraisals, less costs to sell. The appraisals are sometimes further discounted based on management’s historical knowledge, changes in market conditions from the time of valuation, and/or management’s expertise and knowledge of the customer and customer’s business. Such discounts are significant, ranging from 9% to 76.3% at September 30, 2018 and result in a Level 3 classification of the inputs for determining fair value. OREO is reviewed and evaluated on at least a quarterly basis for additional impairment and adjusted accordingly, based on the same factors identified above. The Company recovers the carrying value of OREO through the sale of the property. The ability to affect future sales prices is subject to market conditions and factors beyond the Company’s control and may impact the estimated fair value of a property. Originated mortgage servicing rights are recorded at their fair value at the time of sale of the underlying loan, and are amortized in proportion to and over the estimated period of net servicing income. The fair value of mortgage servicing rights is based on a valuation model incorporating inputs that market participants would use in estimating future net servicing income. Such inputs include estimates of the cost of servicing loans, appropriate discount rate and prepayment speeds and are considered to be unobservable and contribute to the Level 3 classification of mortgage servicing rights. In accordance with GAAP, the Company must record impairment charges, on a nonrecurring basis, when the carrying value of a stratum exceeds its estimated fair value. Impairment is recognized through a valuation allowance. There is no valuation allowance at September 30, 2018. The Company determines fair values based on quoted market values, where available, estimates of present values, or other valuation techniques. Those techniques are significantly affected by the assumptions used, including, but not limited to, the discount rate and estimates of future cash flows. In that regard, the derived fair value estimates cannot be substantiated by comparison to independent markets and, in many cases, may not be realized in immediate settlement of the instrument. The significant unobservable inputs used in the determination of fair value of assets classified as Level 3 on a recurring or non-recurring basis are as follows: (000's omitted) Fair Value at September 30, 2018 Valuation Technique Significant Unobservable Inputs Significant Unobservable Input Range (Weighted Average) Other real estate owned $ 1,142 Fair Value of Collateral Estimated cost of disposal/market adjustment 9.0% - 76.3% (32.3 %) Commitments to originate real estate loans for sale 9 Discounted cash flow Embedded servicing value 1 % (000's omitted) Fair Value at December 31, 2017 Valuation Technique Significant Unobservable Inputs Significant Unobservable Input Range (Weighted Average) Other real estate owned $ 1,915 Fair value of collateral Estimated cost of disposal/market adjustment 9.0% - 99.0% (38.5 %) Commitments to originate real estate loans for sale 89 Discounted cash flow Embedded servicing value 1 % Certain financial instruments and all nonfinancial instruments are excluded from fair value disclosure requirements. Accordingly, the aggregate fair value amounts presented do not represent the underlying value of the Company. The carrying amounts and estimated fair values of the Company’s other financial instruments that are not accounted for at fair value at September 30, 2018 and December 31, 2017 are as follows: September 30, 2018 December 31, 2017 (000's omitted) Carrying Value Fair Value Carrying Value Fair Value Financial assets: Net loans $ 6,250,755 $ 6,171,599 $ 6,209,174 $ 6,244,941 Financial liabilities: Deposits 8,463,821 8,441,535 8,444,420 8,431,481 Short-term borrowings 0 0 24,000 24,000 Securities sold under agreement to repurchase, short-term 274,561 274,561 337,011 337,011 Other long-term debt 1,998 1,915 2,071 2,021 Subordinated debt held by unconsolidated subsidiary trusts 97,939 97,939 122,814 122,814 The following is a further description of the principal valuation methods used by the Company to estimate the fair values of its financial instruments. Loans have been classified as a Level 3 valuation. Fair values for variable rate loans that reprice frequently are based on carrying values. Fair values for fixed rate loans are estimated using discounted cash flows and interest rates currently being offered for loans with similar terms to borrowers of similar credit quality. Deposits have been classified as a Level 2 valuation. The fair value of demand deposits, interest-bearing checking deposits, savings accounts, and money market deposits is the amount payable on demand at the reporting date. The fair value of time deposit obligations are based on current market rates for similar products. Borrowings and subordinated debt held by unconsolidated subsidiary trusts have been classified as a Level 2 valuation. The fair value of short-term borrowings and securities sold under agreement to repurchase, short-term, is the amount payable on demand at the reporting date. Fair values for long-term debt and subordinated debt held by unconsolidated subsidiary trusts are estimated using discounted cash flows and interest rates currently being offered on similar securities. The difference between the carrying value of subordinated debt held by unconsolidated subsidiary trusts, and fair value, is not material as of the reporting dates. Other financial assets and liabilities – Cash and cash equivalents have been classified as a Level 1 valuation, while accrued interest receivable and accrued interest payable have been classified as a Level 2 valuation. The fair values of each approximate the respective carrying values because the instruments are payable on demand or have short-term maturities and present relatively low credit risk and interest rate risk.

DERIVATIVE INSTRUMENTS

DERIVATIVE INSTRUMENTS	9 Months Ended
	Sep. 30, 2018
DERIVATIVE INSTRUMENTS [Abstract]
DERIVATIVE INSTRUMENTS	NOTE L: DERIVATIVE INSTRUMENTS The Company is party to derivative financial instruments in the normal course of its business to meet the financing needs of its customers and to manage its own exposure to fluctuations in interest rates. These financial instruments have been limited to interest rate swap agreements, commitments to originate real estate loans held for sale and forward sales commitments. The Company does not hold or issue derivative financial instruments for trading or other speculative purposes. The Company enters into forward sales commitments for the future delivery of residential mortgage loans, and interest rate lock commitments to fund loans at a specified interest rate. The forward sales commitments are utilized to reduce interest rate risk associated with interest rate lock commitments and loans held for sale. Changes in the estimated fair value of the forward sales commitments and interest rate lock 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. At inception and during the life of the interest rate lock commitment, the Company includes the expected net future cash flows related to the associated servicing of the loan as part of the fair value measurement of the interest rate lock commitments. These derivatives are recorded at fair value, which were immaterial at September 30, 2018. The effect of the changes to these derivatives for the three and nine months then ended was also immaterial. The Company acquired interest rate swaps in the Merchants acquisition with notional amounts with certain commercial customers which totaled $37.5 million at September 30, 2018. In order to minimize the Company’s risk, these customer derivatives (pay floating/receive fixed swaps) have been offset with essentially matching interest rate swaps (pay fixed/receive floating swaps) with the Company’s counterparty totaling $37.5 million. The weighted average receive rate of these interest rate swaps was 4.06%, the weighted average pay rate was 3.84% and the weighted average maturity was 5.7 years. The fair values of $1.3 million and $1.3 million were reflected in other assets and other liabilities, respectively, in the accompanying consolidated statement of condition at September 30, 2018. Hedge accounting has not been applied for these derivatives. Since the terms of the swaps with the customer and the other financial institution offset each other, with the only difference being counterparty credit risk, changes in the fair value of the underlying derivative contracts are not materially different and do not significantly impact our results of operations. The Company also acquired interest rate swaps in the Merchants acquisition with notional amounts totaling $6.6 million at September 30, 2018 that were designated as fair value hedges of certain fixed rate loans with municipalities. At September 30, 2018, the weighted average receive rate of these interest rate swaps was 2.74%, the weighted average pay rate was 3.11% and the weighted average maturity was 14.8 years. The fair value of $0.05 million at September 30, 2018, was reflected as an increase to loans and an increase to other liabilities. The ineffective portion of the interest swaps was immaterial and is not recorded in earnings. The Company assessed its counterparty risk at September 30, 2018 and determined any credit risk inherent in our derivative contracts was not material. Information about the fair value of derivative financial instruments can be found in Note K to these consolidated financial statements.

SEGMENT INFORMATION

SEGMENT INFORMATION	9 Months Ended
	Sep. 30, 2018
SEGMENT INFORMATION [Abstract]
SEGMENT INFORMATION	NOTE M: SEGMENT INFORMATION Operating segments are components of an enterprise, which are evaluated regularly by the “chief operating decision maker” in deciding how to allocate resources and assess performance. The Company’s chief operating decision maker is the President and Chief Executive Officer of the Company. The Company has identified Banking, Employee Benefit Services and All Other as its reportable operating business segments. Community Bank, N.A. (the “Bank” or “CBNA”) operates the Banking segment that provides full-service banking to consumers, businesses, and governmental units in Upstate New York as well as Northeastern Pennsylvania, Vermont and Western Massachusetts. Employee Benefit Services, which includes the operating subsidiaries Benefit Plans Administrative Services, LLC, BPAS Actuarial and Pension Services, LLC, BPAS Trust Company of Puerto Rico, NRS, GTC, and Hand Benefits & Trust Company, provides employee benefit trust, collective investment fund, retirement plan administration, fund administration, transfer agency, actuarial, VEBA/HRA, and health and welfare consulting services. The All Other segment is comprised of: (a) wealth management services including trust services provided by the personal trust unit within the Bank, broker-dealer and investment advisory services provided by CISI and The Carta Group, Inc., as well as asset management provided by Nottingham Advisors, Inc., and (b) full-service insurance, risk management and employee benefit services provided by OneGroup. The accounting policies used in the disclosure of business segments are the same as those described in the summary of significant accounting policies (See Note A: Summary of Significant Accounting Policies Information about reportable segments and reconciliation of the information to the consolidated financial statements follows: (000's omitted) Banking Employee Benefit Services All Other Eliminations Consolidated Total Three Months Ended September 30, 2018 Net interest income $ 86,060 $ 102 $ 36 $ 0 $ 86,198 Provision for loan losses 2,215 0 0 0 2,215 Noninterest revenues 18,002 23,815 14,737 (763 ) 55,791 Amortization of intangible assets 1,535 1,970 922 0 4,427 Acquisition expenses (832 ) 0 0 0 (832 ) Other operating expenses 57,863 14,025 10,513 (763 ) 81,638 Income before income taxes $ 43,281 $ 7,922 $ 3,338 $ 0 $ 54,541 Assets $ 10,440,732 $ 205,565 $ 66,470 $ (53,200 ) $ 10,659,567 Goodwill $ 629,916 $ 83,275 $ 20,288 $ 0 $ 733,479 Three Months Ended September 30, 2017 Net interest income $ 84,227 $ 104 $ 64 $ 0 $ 84,395 Provision for loan losses 2,314 0 0 0 2,314 Noninterest revenues 20,120 21,207 12,298 (684 ) 52,941 Amortization of intangible assets 1,796 2,323 830 0 4,949 Acquisition expenses 534 11 35 0 580 Other operating expenses 56,926 12,788 9,217 (684 ) 78,247 Income before income taxes $ 42,777 $ 6,189 $ 2,280 $ 0 $ 51,246 Assets $ 10,613,065 $ 226,812 $ 77,802 $ (67,461 ) $ 10,850,218 Goodwill $ 629,153 $ 84,448 $ 17,904 $ 0 $ 731,505 (000's omitted) Banking Employee Benefit Services All Other Eliminations Consolidated Total Nine Months Ended September 30, 2018 Net interest income $ 257,313 $ 264 $ 91 $ 0 $ 257,668 Provision for loan losses 8,342 0 0 0 8,342 Noninterest revenues 58,399 70,316 43,285 (2,159 ) 169,841 Amortization of intangible assets 4,914 6,047 2,819 0 13,780 Acquisition expenses (782 ) 7 6 0 (769 ) Other operating expenses 172,283 41,938 32,603 (2,159 ) 244,665 Income before income taxes $ 130,955 $ 22,588 $ 7,948 $ 0 $ 161,491 Nine Months Ended September 30, 2017 Net interest income $ 229,233 $ 276 $ 189 $ 0 $ 229,698 Provision for loan losses 5,603 0 0 0 5,603 Noninterest revenues 54,049 59,961 36,510 (2,035 ) 148,485 Amortization of intangible assets 3,520 6,256 2,204 0 11,980 Acquisition expenses 23,784 1,190 218 0 25,192 Other operating expenses 160,311 37,225 27,557 (2,035 ) 223,058 Income before income taxes $ 90,064 $ 15,566 $ 6,720 $ 0 $ 112,350

BASIS OF PRESENTATION (Policies

BASIS OF PRESENTATION (Policies)	9 Months Ended
	Sep. 30, 2018
BASIS OF PRESENTATION [Abstract]
Basis of Presentation	The interim financial data as of and for the three and nine months ended September 30, 2018 is unaudited; however, in the opinion of Community Bank System, Inc. (the “Company”), the interim data includes all adjustments, consisting only of normal recurring adjustments, necessary for a fair statement of the results for the interim periods in conformity with generally accepted accounting principles (“GAAP”). The results of operations for the interim periods are not necessarily indicative of the results that may be expected for the full year or any other interim period.

ACCOUNTING POLICIES (Policies)

ACCOUNTING POLICIES (Policies)	9 Months Ended
	Sep. 30, 2018
ACCOUNTING POLICIES [Abstract]
Investment Securities	Investment Securities The Company can classify its investments in debt securities as held-to-maturity, available-for-sale, or trading. Held-to-maturity securities are those for which the Company has the positive intent and ability to hold until maturity, and are reported at cost, which is adjusted for amortization of premiums and accretion of discounts. Available-for-sale debt securities are reported at fair value with net unrealized gains and losses reflected as a separate component of shareholders' equity, net of applicable income taxes. Equity securities with a readily determinable fair value are reported at fair value with net unrealized gains and losses recognized in the consolidated statements of income. None of the Company's investment securities have been classified as trading securities at September 30, 2018. Certain equity securities that do not have a readily determinable fair value are stated at cost, less impairment, adjusted for observable price changes in orderly transactions for identical or similar investments of the same issuer. These securities include restricted stock of the Federal Reserve Bank of New York (“Federal Reserve”), the Federal Home Loan Bank of New York and the Federal Home Loan Bank of Boston (collectively referred to as “FHLB”), as well as other equity securities. During the third quarter of 2018, the Company adjusted the carrying value of an equity security without a readily determinable fair value based on observable price changes for identical investments of the same issuer. This adjustment resulted in a $0.8 million unrealized gain on equity securities. Fair values for investment securities are based upon quoted market prices, where available. If quoted market prices are not available, fair values are based upon quoted market prices of comparable instruments, or a discounted cash flow model using market estimates of interest rates and volatility. The Company conducts an assessment of all securities in an unrealized loss An OTTI loss must be recognized for a debt security in an unrealized loss position if there is intent to sell the security or it is more likely than not the Company will be required to sell the security prior to recovery of its amortized cost basis. In this situation, the amount of loss recognized in income is equal to the difference between the fair value and the amortized cost basis of the security. Even if management does not have the intent, and it is not more likely than not that the Company will be required to sell the securities, an evaluation of the expected cash flows to be received is performed to determine if a credit loss has occurred. For debt securities, a critical component of the evaluation for OTTI is the identification of credit-impaired securities, where the Company does not expect to receive cash flows sufficient to recover the entire amortized cost basis of the security. In the event of a credit loss, only the amount of impairment associated with the credit loss would be recognized in income. The portion of the unrealized loss relating to other factors, such as liquidity conditions in the market or changes in market interest rates, is recorded in accumulated other comprehensive loss. The specific identification method is used in determining the realized gains and losses on sales of investment securities and OTTI charges. Premiums and discounts on securities are amortized and accreted, respectively, on the interest method basis over the period to maturity or estimated life of the related security. Purchases and sales of securities are recognized on a trade date basis.
Revenue Recognition	Revenue Recognition On January 1, 2018, the Company adopted ASU No. 2014-09 Revenue from Contracts with Customers (Topic 606) Topic 606 does not apply to revenue associated with financial instruments, including revenue from loans and securities. In addition, certain noninterest income streams such as fees associated with mortgage servicing rights, financial guarantees, derivatives, and certain credit card fees are also not in scope of the newly adopted guidance. Topic 606 is applicable to the Company’s noninterest revenue streams including its deposit related fees, electronic payment interchange fees, merchant income, trust, asset management and other wealth management revenues, insurance commissions and benefit plan services income. However, the recognition of these revenue streams did not change significantly upon adoption of Topic 606. Noninterest revenue streams in-scope of Topic 606 are discussed below. Deposit Service Fees Deposit service fees consist of account activity fees, monthly service fees, check orders, debit and credit card income, ATM fees, Merchant services income and other revenues from processing wire transfers, bill pay service, cashier’s checks and foreign exchange. Debit and credit card income is primarily comprised of interchange fees earned at the time the Company’s debit and credit cards are processed through card payment networks such as Visa. ATM fees are primarily generated when a Company cardholder uses a non-Company ATM or a non-Company cardholder uses a Company ATM. Merchant services income mainly represents fees charged to merchants to process their debit and credit card transactions, in addition to account management fees. The Company’s performance obligation for deposit service fees is generally satisfied, and the related revenue recognized, when the services are rendered or the transaction has been completed. Payment for deposit service fees is typically received at the time it is assessed through a direct charge to customers’ accounts or on a monthly basis. Deposit service fees revenue primarily relates to the Company’s Banking operating segment. Other Banking Services Other banking services consists of other recurring revenue streams such as commissions from sales of credit life insurance, safe deposit box rental fees, mortgage banking income, bank owned life insurance income and other miscellaneous revenue streams. Commissions from the sale of credit life insurance are recognized at the time of sale of the policies. Safe deposit box rental fees are charged to the customer on an annual basis and recognized upon receipt of payment. The Company determined that since rentals and renewals occur fairly consistently over time, revenue is recognized on a basis consistent with the duration of the performance obligation. Mortgage banking income and bank owned life insurance income are not within the scope of Topic 606. Other banking services revenue primarily relates to the Company’s Banking operating segment. Employee Benefit Services Employee benefit services income consists of revenue received from retirement plan services, collective investment fund services, fund administration, transfer agency, consulting and actuarial services. The Company’s performance obligation that relates to plan services are satisfied over time and the resulting fees are recognized monthly or quarterly, based upon the market value of the assets under management and the applicable fee rate or on a time expended basis. Payment is generally received a few days after month end or quarter end. The Company does not earn performance-based incentives. Transactional services such as consulting services, mailings, or other ad hoc services are provided to existing trust and asset management customers. The Company’s performance obligation for these transactional-based services is generally satisfied, and related revenue recognized, at a point in time (i.e., as incurred). Payment is received shortly after services are rendered. Employee benefit services revenue primarily relates to the Company’s Employee Benefit Services operating segment. Insurance Services Insurance services primarily consists of commissions received on insurance product sales and consulting services. The Company acts in the capacity of a broker or agent between the Company’s customer and the insurance carrier. The Company’s performance obligation related to insurance sales for both property and casualty insurance and employee benefit plans is generally satisfied upon the later of the issuance or effective date of the policy. The Company’s performance obligation related to consulting services is considered transactional in nature and is generally satisfied when the services have been completed and related revenue recognized at a point in time. Payment is received at the time services are rendered. The Company earns performance based incentives, commonly known as contingency payments, which usually are based on certain criteria established by the insurance carrier such as premium volume, growth and insured loss ratios. Contingent payments are accrued for based upon management’s expectations for the year. Commission expense associated with sales of insurance products is expensed as incurred. Insurance services revenue primarily relates to the Company’s All Other operating segment. Wealth Management Services Wealth management services income is primarily comprised of fees earned from the management and administration of trusts and other customer assets. The Company generally has two types of performance obligations related to these services. The Company’s performance obligation that relates to advisory and administration services are satisfied over time and the resulting fees are recognized monthly, based upon the market value of the assets under management and the applicable fee rate. Payment is generally received soon after month end or quarter end through a direct charge to customers’ accounts. The Company does not earn performance-based incentives. Transactional services such as tax return preparation services, purchases and sales of investments and insurance products are also available to existing trust and asset management customers. The Company’s performance obligation for these transactional-based services is generally satisfied, and related revenue recognized, at a point in time (i.e. as incurred). Payment is generally received on a monthly basis. Wealth management services revenue primarily relates to the Company’s All Other operating segment. Contract Balances A contract asset balance occurs when an entity performs a service for a customer before the customer pays consideration (resulting in a contract receivable) or before payment is due (resulting in a contract asset). A contract liability balance is an entity’s obligation to transfer a service to a customer for which the entity has already received payment (or payment is due) from the customer. The Company’s noninterest revenue streams are largely based on transactional activity, or standard month-end revenue accruals such as asset management fees based on month-end market values. Consideration is often received immediately or shortly after the Company satisfies its performance obligation and revenue is recognized. The Company does not typically enter into long-term revenue contracts with customers, and therefore, does not experience significant contract balances. As of September 30, 2018, $26.9 million of accounts receivable, including $7.9 million of unbilled fee revenue, and $2.9 million of unearned revenue was recorded in the Consolidated Statements of Condition. As of December 31, 2017, $29.8 million of accounts receivable, including $6.5 million of unbilled fee revenue, and $3.9 million of unearned revenue was recorded in the Consolidated Statements of Condition. Contract Acquisition Costs In connection with the adoption of Topic 606, an entity is required to capitalize, and subsequently amortize into expense, certain incremental costs of obtaining a contract with a customer if these costs are expected to be recovered. The incremental costs of obtaining a contract are those costs that an entity incurs to obtain a contract with a customer that it would not have incurred if the contract had not been obtained (for example, sales commission). The Company utilizes the practical expedient method which allows entities to immediately expense contract acquisition costs when the asset that would have resulted from capitalizing these costs would have been amortized in one year or less. Upon adoption of Topic 606, the Company did not capitalize any contract acquisition costs.
Recently Adopted Accounting Pronouncements	Recently Adopted Accounting Pronouncements In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606) In January 2016, the FASB issued ASU 2016-01, Financial Instruments - Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities. The Company adopted this guidance on January 1, 2018. The impact of the adoption of this guidance resulted in the reclassification of $0.2 million of other comprehensive income to retained earnings. See the Consolidated Statements of Comprehensive Income and Consolidated Statement of Changes in Shareholders’ Equity. In August 2016, the FASB issued ASU No. 2016-15, Statement of Cash Flows (Topic 230) In March 2017, the FASB issued ASU No. 2017-07, Compensation – Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost.
New Accounting Pronouncements	New Accounting Pronouncements In February 2016, the FASB issued ASU 2016-02, Leases (Topic 842) Topic 840, Leases In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments – Credit Losses (Topic 326) In January 2017, the FASB issued ASU No. 2017-04, Intangibles-Goodwill and Other (Topic 350) In August 2017, the FASB issued ASU No. 2017-12, Derivatives and Hedging (Topic 815): Targeted Improvements to Accounting for Hedging Activities.

ACQUISITIONS (Tables)

ACQUISITIONS (Tables)	9 Months Ended
	Sep. 30, 2018
ACQUISITIONS [Abstract]
Estimated Fair Value of Assets Acquired and Liabilities Assumed	The following table summarizes the estimated fair value of the assets acquired and liabilities assumed after considering the measurement period adjustments described above: 2018 2017 (000s omitted) Other (1) NRS Merchants Other (2) Total Consideration paid : Cash $ 1,753 $ 70,073 $ 82,898 $ 6,775 $ 159,746 Community Bank System, Inc. common stock 0 78,483 262,254 2,395 343,132 Total net consideration paid 1,753 148,556 345,152 9,170 502,878 Recognized amounts of identifiable assets acquired and liabilities assumed: Cash and cash equivalents 16 11,063 40,730 339 52,132 Investment securities 0 20,294 370,648 0 390,942 Loans 0 0 1,488,157 0 1,488,157 Premises and equipment 10 411 16,608 27 17,046 Accrued interest receivable 0 72 4,773 0 4,845 Other assets 105 8,088 51,585 583 60,256 Core deposit intangibles 0 0 23,214 0 23,214 Other intangibles 1,343 60,200 2,857 5,626 68,683 Deposits 0 0 (1,448,406 ) 0 (1,448,406 ) Other liabilities (31 ) (26,828 ) (11,750 ) (1,131 ) (39,709 ) Short-term advances 0 0 (80,000 ) 0 (80,000 ) Securities sold under agreement to repurchase, short-term 0 0 (278,076 ) 0 (278,076 ) Long-term debt 0 0 (3,615 ) 0 (3,615 ) Subordinated debt held by unconsolidated subsidiary trusts 0 0 (20,619 ) 0 (20,619 ) Total identifiable assets, net 1,443 73,300 156,106 5,444 234,850 Goodwill $ 310 $ 75,256 $ 189,046 $ 3,726 $ 268,028 (1) (2)
Summary of Loans Acquired	The following is a summary of the loans acquired from Merchants at the date of acquisition: (000s omitted) Acquired Impaired Loans Acquired Non-impaired Loans Total Acquired Loans Contractually required principal and interest at acquisition $ 15,454 $ 1,872,574 $ 1,888,028 Contractual cash flows not expected to be collected (5,385 ) (14,753 ) (20,138 ) Expected cash flows at acquisition 10,069 1,857,821 1,867,890 Interest component of expected cash flows (793 ) (378,940 ) (379,733 ) Fair value of acquired loans $ 9,276 $ 1,478,881 $ 1,488,157

INVESTMENT SECURITIES (Tables)

INVESTMENT SECURITIES (Tables)	9 Months Ended
	Sep. 30, 2018
INVESTMENT SECURITIES [Abstract]
Amortized Cost and Estimated Fair Value of Investment Securities	The amortized cost and estimated fair value of investment securities as of September 30, 2018 and December 31, 2017 are as follows: September 30, 2018 December 31, 2017 (000's omitted) Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Available-for-Sale Portfolio: U.S. Treasury and agency securities $ 2,039 , $ 0 $ 40,991 $ 1,998,095 $ 2,043,023 $ 15,886 $ 4,838 $ 2,054,071 Obligations of state and political subdivisions 473 ,0 5,250 2,933 475,365 514,949 14,064 57 528,956 Government agency mortgage-backed securities 369,970 1,297 13,204 358,063 358,180 3,121 3,763 357,538 Corporate debt securities 2,603 0 53 2,550 2,648 0 25 2,623 Government agency collateralized mortgage obligations 73,112 25 2,431 70,706 88,097 155 878 87,374 Marketable equity securities 0 0 0 0 251 275 0 526 Total available-for-sale portfolio $ 2,957,819 $ 6,572 $ 59,612 $ 2,904,779 $ 3,007,148 $ 33,501 $ 9,561 $ 3,031,088 Equity and other Securities: Equity securities, at fair value $ 251 $ 247 $ 0 $ 498 $ 0 $ 0 $ 0 $ 0 Federal Home Loan Bank common stock 6,343 0 0 6,343 9,896 0 0 9,896 Federal Reserve Bank common stock 30,690 0 0 30,690 30,690 0 0 30,690 Certificates of deposit 0 0 0 0 3,865 0 0 3,865 Other equity securities, at cost 4,997 750 0 5,747 5,840 0 0 5,840 Total equity and other securities $ 42 , $ 997 $ 0 $ 43,278 $ 50,291 $ 0 $ 0 $ 50,291
Summary of Investment Securities That Have Been in a Continuous Unrealized Loss Position for Less Than or Greater Than Twelve Months	A summary of investment securities that have been in a continuous unrealized loss position is as follows: As of September 30, 2018 Less than 12 Months 12 Months or Longer Total (000's omitted) # Fair Value Gross Unrealized Losses # Fair Value Gross Unrealized Losses # Fair Value Gross Unrealized Losses Available-for-Sale Portfolio: U.S. Treasury and agency securities 50 $ 1,633,859 $ 30,625 32 $ 364,236 $ 10,366 82 $ 1,998,095 $ 40,991 Obligations of state and political subdivisions 333 171,781 2,619 9 5,913 314 342 177,694 2,933 Government agency mortgage-backed securities 89 128,752 3,783 136 178,871 9,421 225 307,623 13,204 Corporate debt securities 0 0 0 1 2,550 53 1 2,550 53 Government agency collateralized mortgage obligations 12 8,371 199 36 59,825 2,232 48 68,196 2,431 Total available-for-sale investment portfolio 484 $ 1,942 , $ 37,226 214 $ 611,395 $ 22,386 698 $ 2,554,158 $ 59,612 As of December 31, 2017 Less than 12 Months 12 Months or Longer Total (000's omitted) # Fair Value Gross Unrealized Losses # Fair Value Gross Unrealized Losses # Fair Value Gross Unrealized Losses Available-for-Sale Portfolio: U.S. Treasury and agency securities 44 $ 699,709 $ 4,838 0 $ 0 $ 0 44 $ 699,709 $ 4,838 Obligations of state and political subdivisions 45 23,432 57 0 0 0 45 23,432 57 Government agency mortgage-backed securities 120 185,716 1,433 55 75,712 2,330 175 261,428 3,763 Corporate debt securities 1 2,623 25 0 0 0 1 2,623 25 Government agency collateralized mortgage obligations 39 80,041 878 1 1 0 40 80,042 878 Total available-for-sale investment portfolio 249 $ 991,521 $ 7,231 56 $ 75,713 $ 2,330 305 $ 1,067,234 $ 9,561
Amortized Cost and Estimated Fair Value of Debt Securities by Contractual Maturity	The amortized cost and estimated fair value of debt securities at September 30, 2018, by contractual maturity, are shown below. Expected maturities will differ from contractual maturities because borrowers may have the right to call or prepay obligations with or without call or prepayment penalties. Securities not due at a single maturity date are shown separately. Available-for-Sale (000's omitted) Amortized Cost Fair Value Due in one year or less $ 61,112 $ 60,985 Due after one through five years 2,020,525 1,985,501 Due after five years through ten years 274,222 270,449 Due after ten years 158,878 159,075 Subtotal 2,514,737 2,476,010 Government agency mortgage-backed securities 369,970 358,063 Government agency collateralized mortgage obligations 73,112 70,706 Total $ 2,957,819 $ 2,904,779

LOANS (Tables)

LOANS (Tables)	9 Months Ended
	Sep. 30, 2018
Loans and Leases Receivable Disclosure [Line Items]
Loans Receivable, Net	The balances of these classes are summarized as follows: (000's omitted) September 30, 2018 December 31, 2017 Business lending $ 2,403,624 $ 2,424,223 Consumer mortgage 2,220,022 2,220,298 Consumer indirect 1,098,943 1,011,978 Consumer direct 184,349 179,929 Home equity 393,950 420,329 Gross loans, including deferred origination costs 6,300,888 6,256,757 Allowance for loan losses (50,133 ) (47,583 ) Loans, net of allowance for loan losses $ 6,250,755 $ 6,209,174
Accretable Discount Related to Credit Impaired Acquired Loans	The changes in the accretable discount related to the credit impaired acquired loans are as follows: (000’s omitted) Balance at December 31, 2017 $ 976 Accretion recognized, year-to-date (722 ) Net reclassification between accretable and non-accretable 239 Balance at September 3 0 $ 493
Aged Analysis of Past Due Loans by Class	The following is an aged analysis of the Company’s past due loans, by class as of September 30, 2018: Legacy Loans (000’s omitted) Past Due 30 – 89 Days 90+ Days Past Due and Still Accruing Nonaccrual Total Past Due Current Total Loans Business lending $ 5,751 $ 355 $ 3,335 $ 9,441 $ 1,573,366 $ 1,582,807 Consumer mortgage 10,189 1,767 9,915 21,871 1,793,227 1,815,098 Consumer indirect 12,408 175 0 12,583 1,073,607 1,086,190 Consumer direct 1,510 20 0 1,530 179,399 180,929 Home equity 1,191 371 1,433 2,995 311,817 314,812 Total $ 31,049 $ 2,688 $ 14,683 $ 48,420 $ 4,931,416 $ 4,979,836 Acquired Loans (000’s omitted) Past Due 30 – 89 Days 90+ Days Past Due and Still Accruing Nonaccrual Total Past Due Acquired Impaired (1) Current Total Loans Business lending $ 1,134 $ 0 $ 3,711 $ 4,845 $ 5,851 $ 810,121 $ 820,817 Consumer mortgage 977 215 2,438 3,630 0 401,294 404,924 Consumer indirect 100 34 0 134 0 12,619 12,753 Consumer direct 74 0 0 74 0 3,346 3,420 Home equity 618 14 1,150 1,782 0 77,356 79,138 Total $ 2,903 $ 263 $ 7,299 $ 10,465 $ 5,851 $ 1,304,736 $ 1,321,052 (1) Acquired impaired loans were not classified as nonperforming assets as the loans are considered to be performing under ASC 310-30. As a result interest income, through the accretion of the difference between the carrying amount of the loans and the expected cashflows, is being recognized on all acquired impaired loans. The following is an aged analysis of the Company’s past due loans by class as of December 31, 2017: Legacy Loans (000’s omitted) Past Due 30 – 89 Days 90+ Days Past Due and Still Accruing Nonaccrual Total Past Due Current Total Loans Business lending $ 2,283 $ 571 $ 3,944 $ 6,798 $ 1,369,801 $ 1,376,599 Consumer mortgage 13,564 1,500 10,722 25,786 1,728,823 1,754,609 Consumer indirect 14,197 295 0 14,492 977,344 991,836 Consumer direct 1,875 48 0 1,923 172,556 174,479 Home equity 1,116 94 1,354 2,564 319,576 322,140 Total $ 33,035 $ 2,508 $ 16,020 $ 51,563 $ 4,568,100 $ 4,619,663 Acquired Loans (000’s omitted) Past Due 30 – 89 Days 90+ Days Past Due and Still Accruing Nonaccrual Total Past Due Acquired Impaired (1) Current Total Loans Business lending $ 4,661 $ 0 $ 4,328 $ 8,989 $ 10,115 $ 1,028,520 $ 1,047,624 Consumer mortgage 2,603 26 3,066 5,695 0 459,994 465,689 Consumer indirect 245 8 0 253 0 19,889 20,142 Consumer direct 100 0 0 100 0 5,350 5,450 Home equity 634 170 1,326 2,130 0 96,059 98,189 Total $ 8,243 $ 204 $ 8,720 $ 17,167 $ 10,115 $ 1,609,812 $ 1,637,094 (1) Acquired impaired loans were not classified as nonperforming assets as the loans are considered to be performing under ASC 310-30. As a result interest income, through the accretion of the difference between the carrying amount of the loans and the expected cashflows, is being recognized on all acquired impaired loans.
Summary of Non-Business Impaired Loans	A summary of individually evaluated impaired loans as of September 30, 2018 and December 31, 2017 follows: (000’s omitted) September 30, 2018 December 31, 2017 Loans with allowance allocation $ 3,956 $ 5,125 Loans without allowance allocation 1,151 884 Carrying balance 5,107 6,009 Contractual balance 9,688 9,165 Specifically allocated allowance 956 804
Troubled Debt Restructurings on Financing Receivables	Information regarding TDRs as of September 30, 2018 and December 31, 2017 is as follows: September 30, 2018 December 31, 2017 (000’s omitted) Nonaccrual Accruing Total Nonaccrual Accruing Total # Amount # Amount # Amount # Amount # Amount # Amount Business lending 5 $ 165 3 $ 319 8 $ 484 8 $ 218 7 $ 501 15 $ 719 Consumer mortgage 45 2,000 46 1,783 91 3,783 51 2,265 44 1,750 95 4,015 Consumer indirect 0 0 76 814 76 814 0 0 71 883 71 883 Consumer direct 0 0 22 70 22 70 0 0 25 69 25 69 Home equity 12 215 8 279 20 494 13 245 7 204 20 449 Total 62 $ 2,380 155 $ 3,265 217 $ 5,645 72 $ 2,728 154 $ 3,407 226 $ 6,135 The following table presents information related to loans modified in a TDR during the three months and nine months ended September 30, 2018 and 2017. Of the loans noted in the table below, all loans for the three months and nine months ended September 30, 2018 and 2017 were modified due to a Chapter 7 bankruptcy as described previously. The financial effects of these restructurings were immaterial. Three Months Ended September 30, 2018 Three Months Ended September 30, 2017 (000’s omitted) Number of loans modified Outstanding Balance Number of loans modified Outstanding Balance Business lending 0 $ 0 1 $ 51 Consumer mortgage 4 195 8 540 Consumer indirect 14 117 8 181 Consumer direct 2 10 1 1 Home equity 1 0 1 8 Total 21 $ 322 19 $ 781 Nine Months Ended September 30, 2018 Nine Months Ended September 30, 2017 (000’s omitted) Number of loans modified Outstanding Balance Number of loans modified Outstanding Balance Business lending 1 $ 93 4 $ 414 Consumer mortgage 7 407 15 1,040 Consumer indirect 24 176 22 323 Consumer direct 5 21 4 7 Home equity 2 85 3 106 Total 39 $ 782 48 $ 1,890
Allowance for Loan Losses by Class	The following presents by class the activity in the allowance for loan losses: Three Months Ended (000’s omitted) Business Lending Consumer Mortgage Consumer Indirect Consumer Direct Home Equity Unallocated Acquired Impaired Total Beginning balance $ 18,439 $ 10,473 $ 14,424 $ 3,164 $ 2,015 $ 1,070 $ 33 $ 49,618 Charge-offs (73 ) (144 ) (2,364 ) (465 ) (221 ) 0 0 (3,267 ) Recoveries 93 46 1,190 223 15 0 0 1,567 Provision 321 (205 ) 1,719 299 225 (159 ) 15 2,215 Ending balance $ 18,780 $ 10,170 $ 14,969 $ 3,221 $ 2,034 $ 911 $ 48 $ 50,133 Three Months Ended (000’s omitted) Business Lending Consumer Mortgage Consumer Indirect Consumer Direct Home Equity Unallocated Acquired Impaired Total Beginning balance $ 17,230 $ 10,197 $ 13,918 $ 2,945 $ 2,242 $ 856 $ 63 $ 47,451 Charge-offs (124 ) (198 ) (2,328 ) (574 ) 0 0 0 (3,224 ) Recoveries 127 24 1,058 221 12 0 0 1,442 Provision 399 280 1,130 426 (52 ) 142 (11 ) 2,314 Ending balance $ 17,632 $ 10,303 $ 13,778 $ 3,018 $ 2,202 $ 998 $ 52 $ 47,983 Nine Months Ended (000’s omitted) Business Lending Consumer Mortgage Consumer Indirect Consumer Direct Home Equity Unallocated Acquired Impaired Total Beginning balance $ 17,257 $ 10,465 $ 13,468 $ 3,039 $ 2,107 $ 1,100 $ 147 $ 47,583 Charge-offs (2,000 ) (588 ) (6,031 ) (1,324 ) (325 ) 0 (368 ) (10,636 ) Recoveries 404 109 3,688 612 31 0 0 4,844 Provision 3,119 184 3,844 894 221 (189 ) 269 8,342 Ending balance $ 18,780 $ 10,170 $ 14,969 $ 3,221 $ 2,034 $ 911 $ 48 $ 50,133 Nine Months Ended (000’s omitted) Business Lending Consumer Mortgage Consumer Indirect Consumer Direct Home Equity Unallocated Acquired Impaired Total Beginning balance $ 17,220 $ 10,094 $ 13,782 $ 2,979 $ 2,399 $ 651 $ 108 $ 47,233 Charge-offs (1,062 ) (541 ) (5,969 ) (1,463 ) (228 ) 0 (184 ) (9,447 ) Recoveries 481 42 3,379 648 44 0 0 4,594 Provision 993 708 2,586 854 (13 ) 347 128 5,603 Ending balance $ 17,632 $ 10,303 $ 13,778 $ 3,018 $ 2,202 $ 998 $ 52 $ 47,983
Business Lending [Member]
Loans and Leases Receivable Disclosure [Line Items]
Loans by Credit Quality Indicator	The following table shows the amount of business lending loans by credit quality category: September 30, 2018 December 31, 2017 (000’s omitted) Legacy Acquired Total Legacy Acquired Total Pass $ 1,394,290 $ 740,329 $ 2,134,619 $ 1,170,156 $ 963,981 $ 2,134,137 Special mention 112,777 47,773 160,550 129,076 37,321 166,397 Classified 75,740 25,285 101,025 77,367 34,628 111,995 Doubtful 0 1,579 1,579 0 1,579 1,579 Acquired impaired 0 5,851 5,851 0 10,115 10,115 Total $ 1,582,807 $ 820,817 $ 2,403,624 $ 1,376,599 $ 1,047,624 $ 2,424,223
All Other Loans [Member]
Loans and Leases Receivable Disclosure [Line Items]
Loans by Credit Quality Indicator	The following table details the balances in all other loan categories at September 30, 2018: Legacy Loans (000’s omitted) Consumer Mortgage Consumer Indirect Consumer Direct Home Equity Total Performing $ 1,803,416 $ 1,086,015 $ 180,909 $ 313,008 $ 3,383,348 Nonperforming 11,682 175 20 1,804 13,681 Total $ 1,815,098 $ 1,086,190 $ 180,929 $ 314,812 $ 3,397,029 Acquired Loans (000’s omitted) Consumer Mortgage Consumer Indirect Consumer Direct Home Equity Total Performing $ 402,271 $ 12,719 $ 3,420 $ 77,974 $ 496,384 Nonperforming 2,653 34 0 1,164 3,851 Total $ 404,924 $ 12,753 $ 3,420 $ 79,138 $ 500,235 The following table details the balances in all other loan categories at December 31, 2017: Legacy Loans (000’s omitted) Consumer Mortgage Consumer Indirect Consumer Direct Home Equity Total Performing $ 1,742,387 $ 991,541 $ 174,431 $ 320,692 $ 3,229,051 Nonperforming 12,222 295 48 1,448 14,013 Total $ 1,754,609 $ 991,836 $ 174,479 $ 322,140 $ 3,243,064 Acquired Loans (000’s omitted) Consumer Mortgage Consumer Indirect Consumer Direct Home Equity Total Performing $ 462,597 $ 20,134 $ 5,450 $ 96,693 $ 584,874 Nonperforming 3,092 8 0 1,496 4,596 Total $ 465,689 $ 20,142 $ 5,450 $ 98,189 $ 589,470

GOODWILL AND IDENTIFIABLE INT_2

GOODWILL AND IDENTIFIABLE INTANGIBLE ASSETS (Tables)	9 Months Ended
	Sep. 30, 2018
GOODWILL AND IDENTIFIABLE INTANGIBLE ASSETS [Abstract]
Gross Carrying Amount and Accumulated Amortization of Identifiable Intangible Assets	The gross carrying amount and accumulated amortization for each type of identifiable intangible asset are as follows: September 30, 2018 December 31, 2017 (000's omitted) Gross Carrying Amount Accumulated Amortization Net Carrying Amount Gross Carrying Amount Accumulated Amortization Net Carrying Amount Amortizing intangible assets: Core deposit intangibles $ 62,902 $ (42,790 ) $ 20,112 $ 62,902 $ (37,877 ) $ 25,025 Other intangibles 87,616 (29,507 ) 58,109 86,535 (20,902 ) 65,633 Total amortizing intangibles $ 150,518 $ (72,297 ) $ 78,221 $ 149,437 $ (58,779 ) $ 90,658
Estimated Aggregate Amortization Expense for Each of Five Succeeding Fiscal Years	The estimated aggregate amortization expense for each of the five succeeding fiscal years ended December 31 is as follows: (000's omitted) Oct - Dec 2018 $ 4,375 2019 15,296 2020 12,722 2021 10,853 2022 9,317 Thereafter 25,658 Total $ 78,221
Components of Goodwill	Shown below are the components of the Company’s goodwill at December 31, 2017 and September 30, 2018: (000’s omitted) December 31, 2017 Activity September 30, 2018 Goodwill $ 739,254 $ (951 ) $ 738,303 Accumulated impairment (4,824 ) 0 (4,824 ) Goodwill, net $ 734,430 $ (951 ) $ 733,479

MANDATORILY REDEEMABLE PREFER_2

MANDATORILY REDEEMABLE PREFERRED SECURITIES (Tables)	9 Months Ended
	Sep. 30, 2018
MANDATORILY REDEEMABLE PREFERRED SECURITIES [Abstract]
Terms of Preferred Securities	The terms of the preferred securities of each trust are as follows: Trust Issuance Date Par Amount Interest Rate Maturity Date Call Price CCT IV 12/8/2006 $75.0 million 3 month LIBOR plus 1.65% (3.98%) 12/15/2036 Par MBVT I 12/15/2004 $20.6 million 3 month LIBOR plus 1.95% (4.28%) 12/31/2034 Par

BENEFIT PLANS (Tables)

BENEFIT PLANS (Tables)	9 Months Ended
	Sep. 30, 2018
BENEFIT PLANS [Abstract]
Net Periodic Benefit Cost	The net periodic benefit cost for the three and nine months ended September 30, 2018 and 2017 is as follows: Pension Benefits Post-retirement Benefits Three Months Ended September 30, Nine Months Ended September 30, Three Months Ended September 30, Nine Months Ended September 30, (000's omitted) 2018 2017 2018 2017 2018 2017 2018 2017 Service cost $ 1,154 $ 1,037 $ 3,396 $ 3,143 $ 0 $ 0 $ 0 $ 0 Interest cost 1,422 1,453 4,251 4,265 18 19 52 57 Expected return on plan assets (3,705 ) (3,448 ) (11,115 ) (9,977 ) 0 0 0 0 Amortization of unrecognized net loss 299 148 895 619 5 2 15 6 Amortization of prior service cost (60 ) 13 (225 ) 43 (45 ) (45 ) (134 ) (134 ) Net periodic benefit cost (income) $ (890 ) $ (797 ) $ (2,798 ) $ (1,907 ) $ (22 ) $ (24 ) $ (67 ) $ (71 )

EARNINGS PER SHARE (Tables)

EARNINGS PER SHARE (Tables)	9 Months Ended
	Sep. 30, 2018
EARNINGS PER SHARE [Abstract]
Reconciliation of Basic to Diluted Earnings per Share	The following is a reconciliation of basic to diluted earnings per share for the three and nine months ended September 30, 2018 and 2017: Three Months Ended September 30, Nine Months Ended September 30, (000's omitted, except per share data) 2018 2017 2018 2017 Net income $ 43,106 $ 35,243 $ 127,818 $ 78,691 Income attributable to unvested stock-based compensation awards (191 ) (164 ) (563 ) (387 ) Income available to common shareholders $ 42,915 $ 35,079 $ 127,255 $ 78,304 Weighted-average common shares outstanding – basic 51,250 50,703 51,108 48,189 Basic earnings per share $ 0.84 $ 0.69 $ 2.49 $ 1.62 Net income $ 43,106 $ 35,243 $ 127,818 $ 78,691 Income attributable to unvested stock-based compensation awards (191 ) (164 ) (563 ) (387 ) Income available to common shareholders $ 42,915 $ 35,079 $ 127,255 $ 78,304 Weighted-average common shares outstanding – basic 51,250 50,703 51,108 48,189 Assumed exercise of stock options 608 585 590 640 Weighted-average common shares outstanding – diluted 51,858 51,288 51,698 48,829 Diluted earnings per share $ 0.83 $ 0.68 $ 2.46 $ 1.60

COMMITMENTS, CONTINGENT LIABI_2

COMMITMENTS, CONTINGENT LIABILITIES AND RESTRICTIONS (Tables)	9 Months Ended
	Sep. 30, 2018
COMMITMENTS, CONTINGENT LIABILITIES AND RESTRICTIONS [Abstract]
Off Balance Sheet Financial Instruments Contract Amounts	The contract amounts of commitments and contingencies are as follows: (000's omitted) September 30, 2018 December 31, 2017 Commitments to extend credit $ 1,097,509 $ 1,080,004 Standby letters of credit 32,160 23,782 Total $ 1,129,669 $ 1,103,786

FAIR VALUE (Tables)

FAIR VALUE (Tables)	9 Months Ended
	Sep. 30, 2018
FAIR VALUE [Abstract]
Fair Value Measured on a Recurring Basis	The following tables set forth the Company’s financial assets and liabilities that were accounted for at fair value on a recurring basis. There were no transfers between any of the levels for the periods presented. September 30, 2018 (000's omitted) Level 1 Level 2 Level 3 Total Fair Value Available-for-sale investment securities: U.S. Treasury and agency securities $ 1,867,144 $ 130,951 $ 0 $ 1,998,095 Obligations of state and political subdivisions 0 475,365 0 475,365 Government agency mortgage-backed securities 0 358,063 0 358,063 Corporate debt securities 0 2,550 0 2,550 Government agency collateralized mortgage obligations 0 70,706 0 70,706 Total available-for-sale investment securities 1,867,144 1,037,635 0 2,904,779 Equity securities 498 0 0 498 Mortgage loans held for sale 0 0 0 0 Commitments to originate real estate loans for sale 0 0 9 9 Forward sales commitments 0 9 0 9 Interest rate swap agreements asset 0 1,306 0 1,306 Interest rate swap agreements liability 0 (1,360 ) 0 (1,360 ) Total $ 1,867,642 $ 1,037,590 $ 9 $ 2,905,241 December 31, 2017 (000's omitted) Level 1 Level 2 Level 3 Total Fair Value Available-for-sale investment securities: U.S. Treasury and agency securities $ 1,909,290 $ 144,781 $ 0 $ 2,054,071 Obligations of state and political subdivisions 0 528,956 0 528,956 Government agency mortgage-backed securities 0 357,538 0 357,538 Corporate debt securities 0 2,623 0 2,623 Government agency collateralized mortgage obligations 0 87,374 0 87,374 Marketable equity securities 526 0 0 526 Total available-for-sale investment securities 1,909,816 1,121,272 0 3,031,088 Mortgage loans held for sale 0 461 0 461 Commitments to originate real estate loans for sale 0 0 89 89 Forward sales commitments 0 4 0 4 Interest rate swap agreements asset 0 1,064 0 1,064 Interest rate swap agreements liability 0 (904 ) 0 (904 ) Total $ 1,909,816 $ 1,121,897 $ 89 $ 3,031,802
Assets and Liabilities Measured on a Non-Recurring Basis	The fair value information of assets and liabilities measured on a non-recurring basis presented below is not as of the period-end, but rather as of the date the fair value adjustment was recorded closest to the date presented. September 30, 2018 December 31, 2017 (000's omitted) Level 1 Level 2 Level 3 Total Fair Value Level 1 Level 2 Level 3 Total Fair Value Other real estate owned $ 0 $ 0 $ 1,142 $ 1,142 $ 0 $ 0 $ 1,915 $ 1,915
Significant Unobservable Inputs, Fair Value Valuation Techniques	The significant unobservable inputs used in the determination of fair value of assets classified as Level 3 on a recurring or non-recurring basis are as follows: (000's omitted) Fair Value at September 30, 2018 Valuation Technique Significant Unobservable Inputs Significant Unobservable Input Range (Weighted Average) Other real estate owned $ 1,142 Fair Value of Collateral Estimated cost of disposal/market adjustment 9.0% - 76.3% (32.3 %) Commitments to originate real estate loans for sale 9 Discounted cash flow Embedded servicing value 1 % (000's omitted) Fair Value at December 31, 2017 Valuation Technique Significant Unobservable Inputs Significant Unobservable Input Range (Weighted Average) Other real estate owned $ 1,915 Fair value of collateral Estimated cost of disposal/market adjustment 9.0% - 99.0% (38.5 %) Commitments to originate real estate loans for sale 89 Discounted cash flow Embedded servicing value 1 %
Carrying Amounts and Estimated Fair Values of Other Financial Instruments	The carrying amounts and estimated fair values of the Company’s other financial instruments that are not accounted for at fair value at September 30, 2018 and December 31, 2017 are as follows: September 30, 2018 December 31, 2017 (000's omitted) Carrying Value Fair Value Carrying Value Fair Value Financial assets: Net loans $ 6,250,755 $ 6,171,599 $ 6,209,174 $ 6,244,941 Financial liabilities: Deposits 8,463,821 8,441,535 8,444,420 8,431,481 Short-term borrowings 0 0 24,000 24,000 Securities sold under agreement to repurchase, short-term 274,561 274,561 337,011 337,011 Other long-term debt 1,998 1,915 2,071 2,021 Subordinated debt held by unconsolidated subsidiary trusts 97,939 97,939 122,814 122,814

SEGMENT INFORMATION (Tables)

SEGMENT INFORMATION (Tables)	9 Months Ended
	Sep. 30, 2018
SEGMENT INFORMATION [Abstract]
Segment Reporting Information by Segment	Information about reportable segments and reconciliation of the information to the consolidated financial statements follows: (000's omitted) Banking Employee Benefit Services All Other Eliminations Consolidated Total Three Months Ended September 30, 2018 Net interest income $ 86,060 $ 102 $ 36 $ 0 $ 86,198 Provision for loan losses 2,215 0 0 0 2,215 Noninterest revenues 18,002 23,815 14,737 (763 ) 55,791 Amortization of intangible assets 1,535 1,970 922 0 4,427 Acquisition expenses (832 ) 0 0 0 (832 ) Other operating expenses 57,863 14,025 10,513 (763 ) 81,638 Income before income taxes $ 43,281 $ 7,922 $ 3,338 $ 0 $ 54,541 Assets $ 10,440,732 $ 205,565 $ 66,470 $ (53,200 ) $ 10,659,567 Goodwill $ 629,916 $ 83,275 $ 20,288 $ 0 $ 733,479 Three Months Ended September 30, 2017 Net interest income $ 84,227 $ 104 $ 64 $ 0 $ 84,395 Provision for loan losses 2,314 0 0 0 2,314 Noninterest revenues 20,120 21,207 12,298 (684 ) 52,941 Amortization of intangible assets 1,796 2,323 830 0 4,949 Acquisition expenses 534 11 35 0 580 Other operating expenses 56,926 12,788 9,217 (684 ) 78,247 Income before income taxes $ 42,777 $ 6,189 $ 2,280 $ 0 $ 51,246 Assets $ 10,613,065 $ 226,812 $ 77,802 $ (67,461 ) $ 10,850,218 Goodwill $ 629,153 $ 84,448 $ 17,904 $ 0 $ 731,505 (000's omitted) Banking Employee Benefit Services All Other Eliminations Consolidated Total Nine Months Ended September 30, 2018 Net interest income $ 257,313 $ 264 $ 91 $ 0 $ 257,668 Provision for loan losses 8,342 0 0 0 8,342 Noninterest revenues 58,399 70,316 43,285 (2,159 ) 169,841 Amortization of intangible assets 4,914 6,047 2,819 0 13,780 Acquisition expenses (782 ) 7 6 0 (769 ) Other operating expenses 172,283 41,938 32,603 (2,159 ) 244,665 Income before income taxes $ 130,955 $ 22,588 $ 7,948 $ 0 $ 161,491 Nine Months Ended September 30, 2017 Net interest income $ 229,233 $ 276 $ 189 $ 0 $ 229,698 Provision for loan losses 5,603 0 0 0 5,603 Noninterest revenues 54,049 59,961 36,510 (2,035 ) 148,485 Amortization of intangible assets 3,520 6,256 2,204 0 11,980 Acquisition expenses 23,784 1,190 218 0 25,192 Other operating expenses 160,311 37,225 27,557 (2,035 ) 223,058 Income before income taxes $ 90,064 $ 15,566 $ 6,720 $ 0 $ 112,350

ACQUISITIONS (Details)

ACQUISITIONS (Details) shares in Thousands, $ in Thousands

Apr. 02, 2018USD ($)

Jan. 02, 2018USD ($)

Dec. 04, 2017USD ($)shares

Nov. 17, 2017USD ($)

May 12, 2017USD ($)BranchLocationshares

Mar. 01, 2017USD ($)

Feb. 03, 2017USD ($)

Jan. 01, 2017USD ($)

Sep. 30, 2018USD ($)

Jun. 30, 2018USD ($)

Mar. 31, 2018USD ($)

Sep. 30, 2017USD ($)

Sep. 30, 2018USD ($)

Sep. 30, 2017USD ($)

Dec. 31, 2017USD ($)

Jan. 02, 2017USD ($)

Acquisitions [Abstract]

Cash

$ 1,737

$ 105,402

Goodwill

$ 733,479

$ 731,505

733,479

731,505

$ 734,430

HR Consultants (SA), LLC [Member]

Acquisitions [Abstract]

Cash

$ 300

HR Consultants (SA), LLC [Member] | Customer Lists [Member]

Acquisitions [Abstract]

Intangibles

$ 300

Penna & Associates Agency, Inc. [Member]

Acquisitions [Abstract]

Cash

$ 800

Goodwill

300

Penna & Associates Agency, Inc. [Member] | Customer Lists [Member]

Acquisitions [Abstract]

Intangibles

300

Styles Bridges Associates [Member]

Acquisitions [Abstract]

Cash

700

Styles Bridges Associates [Member] | Customer Lists [Member]

Acquisitions [Abstract]

Intangibles

$ 700

Gordon B. Roberts Agency, Inc [Member]

Acquisitions [Abstract]

Purchase price of acquisition

$ 3,700

Cash

$ 1,350

Issuance of common shares (in shares) | shares

40

Other liabilities

$ 600

Goodwill

2,100

Assets acquired

600

Increase (decrease) in other liabilities as a result of reclassification and adjustment

$ (90)

Increase (decrease) in goodwill as a result of fair value adjustment

$ (90)

Gordon B. Roberts Agency, Inc [Member] | Other Intangibles [Member]

Acquisitions [Abstract]

Intangibles

$ 1,600

Northeast Capital Management, Inc [Member]

Acquisitions [Abstract]

Cash

$ 1,200

Northeast Capital Management, Inc [Member] | Customer Lists [Member]

Acquisitions [Abstract]

Intangibles

$ 1,200

Merchants Bancshares, Inc. [Member]

Acquisitions [Abstract]

Purchase price of acquisition

$ 345,152

Cash

$ 82,898

Issuance of common shares (in shares) | shares

4,680

Other liabilities

$ 11,750

Goodwill

189,046

Assets acquired

$ 2,000,000

Revenues earned

14,700

16,800

46,800

25,800

Expenses incurred

7,400

7,500

22,700

11,500

Merchants Bancshares, Inc. [Member] | VERMONT [Member]

Acquisitions [Abstract]

Number of branch locations added upon merger | Branch

31

Merchants Bancshares, Inc. [Member] | Massachusetts [Member]

Acquisitions [Abstract]

Number of branch locations added upon merger | Location

1

Merchants Bancshares, Inc. [Member] | Other Intangibles [Member]

Acquisitions [Abstract]

Intangibles

$ 2,857

Dryfoos [Member]

Acquisitions [Abstract]

Cash

$ 3,000

Goodwill

1,700

Dryfoos [Member] | Other Intangibles [Member]

Acquisitions [Abstract]

Intangibles

$ 1,700

BAS [Member]

Acquisitions [Abstract]

Cash

$ 1,200

BAS [Member] | Other Intangibles [Member]

Acquisitions [Abstract]

Intangibles

$ 1,200

Northeast Retirement Services, Inc. [Member]

Acquisitions [Abstract]

Purchase price of acquisition

$ 148,556

Cash

70,073

Other liabilities

26,828

Goodwill

75,256

Tangible assets, net

$ 36,100

Factor of straight-line rate of depreciation used in declining balance depreciation method

150.00%

Period of amortization

10 years

Deferred tax liability

$ 23,000

Revenues earned

10,300

8,700

30,100

22,100

Expenses incurred

$ 6,100

$ 5,800

$ 18,100

$ 15,100

Increase (decrease) in other liabilities as a result of reclassification and adjustment

$ (1,200)

Increase (decrease) in goodwill as a result of fair value adjustment

$ (1,200)

Northeast Retirement Services, Inc. [Member] | Other Intangibles [Member]

Acquisitions [Abstract]

Intangibles

$ 60,200

ACQUISITIONS, Estimated Fair Va

ACQUISITIONS, Estimated Fair Value of Assets Acquired and Liabilities Assumed (Details) - USD ($) $ in Thousands		Apr. 02, 2018	May 12, 2017	Feb. 03, 2017	Jan. 01, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017	Jan. 02, 2017
Consideration paid [Abstract]
Cash						$ 1,737	$ 105,402
Recognized amounts of identifiable assets acquired and liabilities assumed [Abstract]
Goodwill						733,479	$ 731,505	$ 734,430
Other [Member]
Consideration paid [Abstract]
Cash	[1]	$ 1,753
Community Bank System, Inc. common stock	[1]	0
Total net consideration paid	[1]	1,753
Recognized amounts of identifiable assets acquired and liabilities assumed [Abstract]
Cash and cash equivalents	[1]	16
Investment securities	[1]	0
Loans	[1]	0
Premises and equipment	[1]	10
Accrued interest receivable	[1]	0
Other assets	[1]	105
Deposits	[1]	0
Other liabilities	[1]	(31)
Short-term advances	[1]	0
Securities sold under agreement to repurchase, short-term	[1]	0
Long-term debt	[1]	0
Subordinated debt held by unconsolidated subsidiary trusts	[1]	0
Total identifiable assets, net	[1]	1,443
Goodwill	[1]	310
Other [Member] | Core Deposits [Member]
Recognized amounts of identifiable assets acquired and liabilities assumed [Abstract]
Intangibles	[1]	0
Other [Member] | Other Intangibles [Member]
Recognized amounts of identifiable assets acquired and liabilities assumed [Abstract]
Intangibles	[1]	$ 1,343
BAS [Member]
Consideration paid [Abstract]
Cash					$ 1,200
BAS [Member] | Other Intangibles [Member]
Recognized amounts of identifiable assets acquired and liabilities assumed [Abstract]
Intangibles									$ 1,200
NRS [Member]
Consideration paid [Abstract]
Cash				$ 70,073
Community Bank System, Inc. common stock				78,483
Total net consideration paid				148,556
Recognized amounts of identifiable assets acquired and liabilities assumed [Abstract]
Cash and cash equivalents				11,063
Investment securities				20,294
Loans				0
Premises and equipment				411
Accrued interest receivable				72
Other assets				8,088
Deposits				0
Other liabilities				(26,828)
Short-term advances				0
Securities sold under agreement to repurchase, short-term				0
Long-term debt				0
Subordinated debt held by unconsolidated subsidiary trusts				0
Total identifiable assets, net				73,300
Goodwill				75,256
NRS [Member] | Core Deposits [Member]
Recognized amounts of identifiable assets acquired and liabilities assumed [Abstract]
Intangibles				0
NRS [Member] | Other Intangibles [Member]
Recognized amounts of identifiable assets acquired and liabilities assumed [Abstract]
Intangibles				$ 60,200
Merchants Bancshares, Inc. [Member]
Consideration paid [Abstract]
Cash			$ 82,898
Community Bank System, Inc. common stock			262,254
Total net consideration paid			345,152
Recognized amounts of identifiable assets acquired and liabilities assumed [Abstract]
Cash and cash equivalents			40,730
Investment securities			370,648
Loans			1,488,157
Premises and equipment			16,608
Accrued interest receivable			4,773
Other assets			51,585
Deposits			(1,448,406)
Other liabilities			(11,750)
Short-term advances			(80,000)
Securities sold under agreement to repurchase, short-term			(278,076)
Long-term debt			(3,615)
Subordinated debt held by unconsolidated subsidiary trusts			(20,619)
Total identifiable assets, net			156,106
Goodwill			189,046
Merchants Bancshares, Inc. [Member] | Core Deposits [Member]
Recognized amounts of identifiable assets acquired and liabilities assumed [Abstract]
Intangibles			23,214
Merchants Bancshares, Inc. [Member] | Other Intangibles [Member]
Recognized amounts of identifiable assets acquired and liabilities assumed [Abstract]
Intangibles			$ 2,857
Other [Member]
Consideration paid [Abstract]
Cash	[2]					6,775
Community Bank System, Inc. common stock	[2]					2,395
Total net consideration paid	[2]					9,170
Recognized amounts of identifiable assets acquired and liabilities assumed [Abstract]
Cash and cash equivalents	[2]					339
Investment securities	[2]					0
Loans	[2]					0
Premises and equipment	[2]					27
Accrued interest receivable	[2]					0
Other assets	[2]					583
Deposits	[2]					0
Other liabilities	[2]					(1,131)
Short-term advances	[2]					0
Securities sold under agreement to repurchase, short-term	[2]					0
Long-term debt	[2]					0
Subordinated debt held by unconsolidated subsidiary trusts	[2]					0
Total identifiable assets, net	[2]					5,444
Goodwill	[2]					3,726
Other [Member] | Core Deposits [Member]
Recognized amounts of identifiable assets acquired and liabilities assumed [Abstract]
Intangibles	[2]					0
Other [Member] | Other Intangibles [Member]
Recognized amounts of identifiable assets acquired and liabilities assumed [Abstract]
Intangibles	[2]					5,626
Total [Member]
Consideration paid [Abstract]
Cash						159,746
Community Bank System, Inc. common stock						343,132
Total net consideration paid						502,878
Recognized amounts of identifiable assets acquired and liabilities assumed [Abstract]
Cash and cash equivalents						52,132
Investment securities						390,942
Loans						1,488,157
Premises and equipment						17,046
Accrued interest receivable						4,845
Other assets						60,256
Deposits						(1,448,406)
Other liabilities						(39,709)
Short-term advances						(80,000)
Securities sold under agreement to repurchase, short-term						(278,076)
Long-term debt						(3,615)
Subordinated debt held by unconsolidated subsidiary trusts						(20,619)
Total identifiable assets, net						234,850
Goodwill						268,028
Total [Member] | Core Deposits [Member]
Recognized amounts of identifiable assets acquired and liabilities assumed [Abstract]
Intangibles						23,214
Total [Member] | Other Intangibles [Member]
Recognized amounts of identifiable assets acquired and liabilities assumed [Abstract]
Intangibles						$ 68,683
[1]	Includes amounts related to the Penna, Styles Bridges and HR Consultants acquisitions.
[2]	Includes amounts related to the BAS, Dryfoos, NECM and GBR acquisitions.

ACQUISITIONS, Summary of Loans

ACQUISITIONS, Summary of Loans Acquired (Details) - Merchants Bancshares, Inc. [Member] $ in Thousands	May 12, 2017USD ($)
Summary of loans acquired [Abstract]
Contractually required principal and interest at acquisition	$ 1,888,028
Contractual cash flows not expected to be collected	(20,138)
Expected cash flows at acquisition	1,867,890
Interest component of expected cash flows	(379,733)
Fair value of acquired loans	1,488,157
Acquired Impaired Loans [Member]
Summary of loans acquired [Abstract]
Contractually required principal and interest at acquisition	15,454
Contractual cash flows not expected to be collected	(5,385)
Expected cash flows at acquisition	10,069
Interest component of expected cash flows	(793)
Fair value of acquired loans	9,276
Acquired Non-impaired Loans [Member]
Summary of loans acquired [Abstract]
Contractually required principal and interest at acquisition	1,872,574
Contractual cash flows not expected to be collected	(14,753)
Expected cash flows at acquisition	1,857,821
Interest component of expected cash flows	(378,940)
Fair value of acquired loans	$ 1,478,881

ACQUISITIONS, Intangible Asset,

ACQUISITIONS, Intangible Asset, Goodwill and Acquisition-related Expenses (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Summary of loans acquired [Abstract]
Merger and acquisition integration-related expenses	$ (832)	$ 580	$ (769)	$ 25,192
HR Consultants (SA), LLC [Member] | Core Deposits [Member]
Intangible Assets [Abstract]
Estimated useful life			8 years
HR Consultants (SA), LLC [Member] | Other Intangibles [Member]
Intangible Assets [Abstract]
Estimated useful life			8 years
Penna & Associates Agency, Inc. [Member] | Core Deposits [Member]
Intangible Assets [Abstract]
Estimated useful life			8 years
Penna & Associates Agency, Inc. [Member] | Other Intangibles [Member]
Intangible Assets [Abstract]
Estimated useful life			8 years
Styles Bridges Associates [Member] | Core Deposits [Member]
Intangible Assets [Abstract]
Estimated useful life			8 years
Styles Bridges Associates [Member] | Other Intangibles [Member]
Intangible Assets [Abstract]
Estimated useful life			8 years
Gordon B. Roberts Agency, Inc [Member] | Core Deposits [Member]
Intangible Assets [Abstract]
Estimated useful life			8 years
Gordon B. Roberts Agency, Inc [Member] | Other Intangibles [Member]
Intangible Assets [Abstract]
Estimated useful life			8 years
Northeast Capital Management, Inc [Member] | Core Deposits [Member]
Intangible Assets [Abstract]
Estimated useful life			8 years
Northeast Capital Management, Inc [Member] | Other Intangibles [Member]
Intangible Assets [Abstract]
Estimated useful life			8 years
Merchants Bancshares, Inc. [Member] | Core Deposits [Member]
Intangible Assets [Abstract]
Estimated useful life			8 years
Merchants Bancshares, Inc. [Member] | Other Intangibles [Member]
Intangible Assets [Abstract]
Estimated useful life			8 years
Dryfoos Insurance Agency, Inc [Member] | Core Deposits [Member]
Intangible Assets [Abstract]
Estimated useful life			8 years
Dryfoos Insurance Agency, Inc [Member] | Other Intangibles [Member]
Intangible Assets [Abstract]
Estimated useful life			8 years
Benefits Advisory Service, Inc [Member] | Core Deposits [Member]
Intangible Assets [Abstract]
Estimated useful life			8 years
Benefits Advisory Service, Inc [Member] | Other Intangibles [Member]
Intangible Assets [Abstract]
Estimated useful life			8 years

ACCOUNTING POLICIES (Details)

ACCOUNTING POLICIES (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018USD ($)Type	Sep. 30, 2017USD ($)	Sep. 30, 2018USD ($)Type	Sep. 30, 2017USD ($)	Dec. 31, 2017USD ($)
Investment Securities [Abstract]
Unrealized gain on equity securities	$ 800
Wealth Management Services [Abstract]
Number of types of performance obligations | Type	2		2
Contract Balances [Abstract]
Accounts receivable	$ 26,900		$ 26,900		$ 29,800
Unbilled fee revenue	7,900		7,900		6,500
Unearned revenue	2,900		2,900		3,900
Recently Adopted Accounting Pronouncements [Abstract]
Reclassification of other comprehensive income to retained earnings					0
Salaries and employee benefits	51,062	$ 48,426	155,323	$ 137,897
Other expenses	5,188	6,052	14,793	16,078
Retained Earnings [Member]
Recently Adopted Accounting Pronouncements [Abstract]
Reclassification of other comprehensive income to retained earnings					208
Accumulated Other Comprehensive Loss [Member]
Recently Adopted Accounting Pronouncements [Abstract]
Reclassification of other comprehensive income to retained earnings					$ (208)
ASU 2017-07 [Member]
Recently Adopted Accounting Pronouncements [Abstract]
Salaries and employee benefits		(1,900)		(5,100)
Other expenses		$ 1,900		$ 5,100
ASU 2016-01 [Member] | Retained Earnings [Member]
Recently Adopted Accounting Pronouncements [Abstract]
Reclassification of other comprehensive income to retained earnings	208		208
ASU 2016-01 [Member] | Accumulated Other Comprehensive Loss [Member]
Recently Adopted Accounting Pronouncements [Abstract]
Reclassification of other comprehensive income to retained earnings	$ (208)		$ (208)

INVESTMENT SECURITIES, Availabl

INVESTMENT SECURITIES, Available-for-Sale Portfolio (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Available-for-Sale Portfolio [Abstract]
Amortized cost	$ 2,957,819	$ 3,007,148
Gross unrealized gains	6,572	33,501
Gross unrealized losses	59,612	9,561
Fair value	2,904,779	3,031,088
Debt Securities, Available-for-sale, Fair Value to Amortized Cost [Abstract]
Amortized cost	2,957,819
Fair value	2,904,779
Marketable Equity Securities [Abstract]
Amortized cost	0	251
Gross unrealized gains	0	275
Gross unrealized losses	0	0
Fair value	0	526
U.S. Treasury and Agency Securities [Member]
Debt Securities, Available-for-sale, Fair Value to Amortized Cost [Abstract]
Amortized cost	2,039,086	2,043,023
Gross unrealized gains	0	15,886
Gross unrealized losses	40,991	4,838
Fair value	1,998,095	2,054,071
Obligations of State and Political Subdivisions [Member]
Debt Securities, Available-for-sale, Fair Value to Amortized Cost [Abstract]
Amortized cost	473,048	514,949
Gross unrealized gains	5,250	14,064
Gross unrealized losses	2,933	57
Fair value	475,365	528,956
Government Agency Mortgage-Backed Securities [Member]
Debt Securities, Available-for-sale, Fair Value to Amortized Cost [Abstract]
Amortized cost	369,970	358,180
Gross unrealized gains	1,297	3,121
Gross unrealized losses	13,204	3,763
Fair value	358,063	357,538
Corporate Debt Securities [Member]
Debt Securities, Available-for-sale, Fair Value to Amortized Cost [Abstract]
Amortized cost	2,603	2,648
Gross unrealized gains	0	0
Gross unrealized losses	53	25
Fair value	2,550	2,623
Government Agency Collateralized Mortgage Obligations [Member]
Debt Securities, Available-for-sale, Fair Value to Amortized Cost [Abstract]
Amortized cost	73,112	88,097
Gross unrealized gains	25	155
Gross unrealized losses	2,431	878
Fair value	$ 70,706	$ 87,374

INVESTMENT SECURITIES, Equity a

INVESTMENT SECURITIES, Equity and Other Securities (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Equity and Other Securities [Abstract]
Amortized cost	$ 42,281	$ 50,291
Gross unrealized gains	997	0
Gross unrealized losses	0	0
Fair value	43,278	50,291
Equity Securities, at Fair Value [Abstract]
Amortized cost	251	0
Gross unrealized gains	247	0
Gross unrealized losses	0	0
Fair value	498	0
Federal Home Loan Bank Common Stock [Member]
Other Securities [Abstract]
Amortized cost	6,343	9,896
Fair value	6,343	9,896
Federal Reserve Bank Common Stock [Member]
Other Securities [Abstract]
Amortized cost	30,690	30,690
Fair value	30,690	30,690
Certificates of Deposit [Member]
Other Securities [Abstract]
Amortized cost	0	3,865
Fair value	0	3,865
Other Equity Securities [Member]
Other Securities [Abstract]
Amortized cost	4,997	5,840
Gross unrealized gains	750	0
Fair value	$ 5,747	$ 5,840

INVESTMENT SECURITIES, Investme

INVESTMENT SECURITIES, Investment Securities in a Continuous Unrealized Loss Position (Details) $ in Thousands	Sep. 30, 2018USD ($)Position	Dec. 31, 2017USD ($)Position
Available-for-Sale Portfolio in Unrealized Loss Positions, Number of Positions [Abstract]
Less than 12 months | Position	484	249
12 months or longer | Position	214	56
Total | Position	698	305
Available-for-Sale Securities, in Unrealized Loss Position, Fair Value [Abstract]
Less than 12 months	$ 1,942,763	$ 991,521
12 months or longer	611,395	75,713
Total	2,554,158	1,067,234
Available-for-Sale Portfolio, Debt Maturities, Gross Unrealized Losses [Abstract]
Less than 12 months	37,226	7,231
12 months or longer	22,386	2,330
Total	$ 59,612	$ 9,561
U.S. Treasury and Agency Securities [Member]
Available-for-Sale Portfolio in Unrealized Loss Positions, Number of Positions [Abstract]
Less than 12 months | Position	50	44
12 months or longer | Position	32	0
Total | Position	82	44
Available-for-Sale Securities, in Unrealized Loss Position, Fair Value [Abstract]
Less than 12 months	$ 1,633,859	$ 699,709
12 months or longer	364,236	0
Total	1,998,095	699,709
Available-for-Sale Portfolio, Debt Maturities, Gross Unrealized Losses [Abstract]
Less than 12 months	30,625	4,838
12 months or longer	10,366	0
Total	$ 40,991	$ 4,838
Obligations of State and Political Subdivisions [Member]
Available-for-Sale Portfolio in Unrealized Loss Positions, Number of Positions [Abstract]
Less than 12 months | Position	333	45
12 months or longer | Position	9	0
Total | Position	342	45
Available-for-Sale Securities, in Unrealized Loss Position, Fair Value [Abstract]
Less than 12 months	$ 171,781	$ 23,432
12 months or longer	5,913	0
Total	177,694	23,432
Available-for-Sale Portfolio, Debt Maturities, Gross Unrealized Losses [Abstract]
Less than 12 months	2,619	57
12 months or longer	314	0
Total	$ 2,933	$ 57
Government Agency Mortgage-Backed Securities [Member]
Available-for-Sale Portfolio in Unrealized Loss Positions, Number of Positions [Abstract]
Less than 12 months | Position	89	120
12 months or longer | Position	136	55
Total | Position	225	175
Available-for-Sale Securities, in Unrealized Loss Position, Fair Value [Abstract]
Less than 12 months	$ 128,752	$ 185,716
12 months or longer	178,871	75,712
Total	307,623	261,428
Available-for-Sale Portfolio, Debt Maturities, Gross Unrealized Losses [Abstract]
Less than 12 months	3,783	1,433
12 months or longer	9,421	2,330
Total	$ 13,204	$ 3,763
Corporate Debt Securities [Member]
Available-for-Sale Portfolio in Unrealized Loss Positions, Number of Positions [Abstract]
Less than 12 months | Position	0	1
12 months or longer | Position	1	0
Total | Position	1	1
Available-for-Sale Securities, in Unrealized Loss Position, Fair Value [Abstract]
Less than 12 months	$ 0	$ 2,623
12 months or longer	2,550	0
Total	2,550	2,623
Available-for-Sale Portfolio, Debt Maturities, Gross Unrealized Losses [Abstract]
Less than 12 months	0	25
12 months or longer	53	0
Total	$ 53	$ 25
Government Agency Collateralized Mortgage Obligations [Member]
Available-for-Sale Portfolio in Unrealized Loss Positions, Number of Positions [Abstract]
Less than 12 months | Position	12	39
12 months or longer | Position	36	1
Total | Position	48	40
Available-for-Sale Securities, in Unrealized Loss Position, Fair Value [Abstract]
Less than 12 months	$ 8,371	$ 80,041
12 months or longer	59,825	1
Total	68,196	80,042
Available-for-Sale Portfolio, Debt Maturities, Gross Unrealized Losses [Abstract]
Less than 12 months	199	878
12 months or longer	2,232	0
Total	$ 2,431	$ 878

INVESTMENT SECURITIES, Amortize

INVESTMENT SECURITIES, Amortized Cost and Estimated Fair Value of Debt Securities by Contractual Maturity (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Available-for-Sale, Debt Maturities, Amortized Cost [Abstract]
Due in one year or less	$ 61,112
Due after one through five years	2,020,525
Due after five years through ten years	274,222
Due after ten years	158,878
Subtotal	2,514,737
Amortized cost	2,957,819
Available-for-Sale, Debt Maturities, Fair Value [Abstract]
Due in one year or less	60,985
Due after one through five years	1,985,501
Due after five years through ten years	270,449
Due after ten years	159,075
Subtotal	2,476,010
Fair value	2,904,779
Government Agency Mortgage-Backed Securities [Member]
Available-for-Sale, Debt Maturities, Amortized Cost [Abstract]
Without single maturity date	369,970
Amortized cost	369,970	$ 358,180
Available-for-Sale, Debt Maturities, Fair Value [Abstract]
Without single maturity date	358,063
Fair value	358,063	357,538
Government Agency Collateralized Mortgage Obligations [Member]
Available-for-Sale, Debt Maturities, Amortized Cost [Abstract]
Without single maturity date	73,112
Amortized cost	73,112	88,097
Available-for-Sale, Debt Maturities, Fair Value [Abstract]
Without single maturity date	70,706
Fair value	70,706	87,374
U.S. Treasury Securities [Member]
Available-for-Sale, Debt Maturities, Amortized Cost [Abstract]
Amortized cost	2,039,086	2,043,023
Available-for-Sale, Debt Maturities, Fair Value [Abstract]
Fair value	1,998,095	$ 2,054,071
Securities pledged as collateral for securities sold under agreement to repurchase	$ 289,000

LOANS, Loan Summary (Details)

LOANS, Loan Summary (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Jun. 30, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Dec. 31, 2016
Loans receivable, net [Abstract]
Gross loans, including deferred origination costs	$ 6,300,888		$ 6,256,757
Allowance for loan losses	(50,133)	$ (49,618)	(47,583)	$ (47,983)	$ (47,451)	$ (47,233)
Net loans	6,250,755		6,209,174
Credit impaired acquired loans, total balance due	7,800		13,400
Accretable discount related to credit impaired acquired loans [Roll forward]
Beginning Balance	976
Accretion recognized, year-to-date	(722)
Net reclassification between accretable and non-accretable	239
Ending Balance	493
Business Lending [Member]
Loans receivable, net [Abstract]
Gross loans, including deferred origination costs	$ 2,403,624		2,424,223
Consumer Mortgage [Member] | Minimum [Member]
Loans receivable, net [Abstract]
Typical contract term	10 years
Consumer Mortgage [Member] | Maximum [Member]
Loans receivable, net [Abstract]
Typical contract term	30 years
Home Equity [Member] | Maximum [Member]
Loans receivable, net [Abstract]
Typical contract term	30 years
Commercial Portfolio Segment [Member] | Business Lending [Member]
Loans receivable, net [Abstract]
Gross loans, including deferred origination costs	$ 2,403,624		2,424,223
Commercial Portfolio Segment [Member] | Consumer Mortgage [Member]
Loans receivable, net [Abstract]
Allowance for loan losses	(10,170)	(10,473)	(10,465)	(10,303)	(10,197)	(10,094)
Residential Portfolio Segment [Member] | Business Lending [Member]
Loans receivable, net [Abstract]
Allowance for loan losses	(18,780)	(18,439)	(17,257)	(17,632)	(17,230)	(17,220)
Residential Portfolio Segment [Member] | Consumer Mortgage [Member]
Loans receivable, net [Abstract]
Gross loans, including deferred origination costs	2,220,022		2,220,298
Consumer Portfolio Segment [Member] | Consumer Indirect [Member]
Loans receivable, net [Abstract]
Gross loans, including deferred origination costs	1,098,943		1,011,978
Allowance for loan losses	(14,969)	(14,424)	(13,468)	(13,778)	(13,918)	(13,782)
Consumer Portfolio Segment [Member] | Consumer Direct [Member]
Loans receivable, net [Abstract]
Gross loans, including deferred origination costs	184,349		179,929
Allowance for loan losses	(3,221)	(3,164)	(3,039)	(3,018)	(2,945)	(2,979)
Consumer Portfolio Segment [Member] | Home Equity [Member]
Loans receivable, net [Abstract]
Gross loans, including deferred origination costs	393,950		420,329
Allowance for loan losses	$ (2,034)	$ (2,015)	$ (2,107)	$ (2,202)	$ (2,242)	$ (2,399)

LOANS, Credit Quality By Past D

LOANS, Credit Quality By Past Due Status (Details) - USD ($) $ in Thousands		Sep. 30, 2018	Dec. 31, 2017
Aged analysis of the company's loans [Abstract]
Total loans		$ 6,300,888	$ 6,256,757
Legacy Loans [Member]
Aged analysis of the company's loans [Abstract]
90 + days past due and still accruing		2,688	2,508
Nonaccrual		14,683	16,020
Total past due		48,420	51,563
Current		4,931,416	4,568,100
Total loans		4,979,836	4,619,663
Legacy Loans [Member] | Past Due 30 - 89 Days [Member]
Aged analysis of the company's loans [Abstract]
Total past due		31,049	33,035
Acquired Loans [Member]
Aged analysis of the company's loans [Abstract]
90 + days past due and still accruing		263	204
Nonaccrual		7,299	8,720
Total past due		10,465	17,167
Acquired impaired	[1]	5,851	10,115
Current		1,304,736	1,609,812
Total loans		1,321,052	1,637,094
Acquired Loans [Member] | Past Due 30 - 89 Days [Member]
Aged analysis of the company's loans [Abstract]
Total past due		2,903	8,243
Business Lending [Member]
Aged analysis of the company's loans [Abstract]
Total loans		2,403,624	2,424,223
Business Lending [Member] | Legacy Loans [Member]
Aged analysis of the company's loans [Abstract]
Total loans		1,582,807	1,376,599
Business Lending [Member] | Acquired Loans [Member]
Aged analysis of the company's loans [Abstract]
Total loans		820,817	1,047,624
Consumer Mortgage [Member] | Legacy Loans [Member]
Aged analysis of the company's loans [Abstract]
Total loans		1,815,098	1,754,609
Consumer Mortgage [Member] | Acquired Loans [Member]
Aged analysis of the company's loans [Abstract]
Total loans		404,924	465,689
Consumer Indirect [Member] | Legacy Loans [Member]
Aged analysis of the company's loans [Abstract]
Total loans		1,086,190	991,836
Consumer Indirect [Member] | Acquired Loans [Member]
Aged analysis of the company's loans [Abstract]
Total loans		12,753	20,142
Consumer Direct [Member] | Legacy Loans [Member]
Aged analysis of the company's loans [Abstract]
Total loans		180,929	174,479
Consumer Direct [Member] | Acquired Loans [Member]
Aged analysis of the company's loans [Abstract]
Total loans		3,420	5,450
Home Equity [Member] | Legacy Loans [Member]
Aged analysis of the company's loans [Abstract]
Total loans		314,812	322,140
Home Equity [Member] | Acquired Loans [Member]
Aged analysis of the company's loans [Abstract]
Total loans		79,138	98,189
Commercial Portfolio Segment [Member] | Business Lending [Member]
Aged analysis of the company's loans [Abstract]
Total loans		2,403,624	2,424,223
Commercial Portfolio Segment [Member] | Business Lending [Member] | Legacy Loans [Member]
Aged analysis of the company's loans [Abstract]
90 + days past due and still accruing		355	571
Nonaccrual		3,335	3,944
Total past due		9,441	6,798
Current		1,573,366	1,369,801
Total loans		1,582,807	1,376,599
Commercial Portfolio Segment [Member] | Business Lending [Member] | Legacy Loans [Member] | Past Due 30 - 89 Days [Member]
Aged analysis of the company's loans [Abstract]
Total past due		5,751	2,283
Commercial Portfolio Segment [Member] | Business Lending [Member] | Acquired Loans [Member]
Aged analysis of the company's loans [Abstract]
90 + days past due and still accruing		0	0
Nonaccrual		3,711	4,328
Total past due		4,845	8,989
Acquired impaired	[1]	5,851	10,115
Current		810,121	1,028,520
Total loans		820,817	1,047,624
Commercial Portfolio Segment [Member] | Business Lending [Member] | Acquired Loans [Member] | Past Due 30 - 89 Days [Member]
Aged analysis of the company's loans [Abstract]
Total past due		1,134	4,661
Residential Portfolio Segment [Member] | Consumer Mortgage [Member]
Aged analysis of the company's loans [Abstract]
Total loans		2,220,022	2,220,298
Residential Portfolio Segment [Member] | Consumer Mortgage [Member] | Legacy Loans [Member]
Aged analysis of the company's loans [Abstract]
90 + days past due and still accruing		1,767	1,500
Nonaccrual		9,915	10,722
Total past due		21,871	25,786
Current		1,793,227	1,728,823
Total loans		1,815,098	1,754,609
Residential Portfolio Segment [Member] | Consumer Mortgage [Member] | Legacy Loans [Member] | Past Due 30 - 89 Days [Member]
Aged analysis of the company's loans [Abstract]
Total past due		10,189	13,564
Residential Portfolio Segment [Member] | Consumer Mortgage [Member] | Acquired Loans [Member]
Aged analysis of the company's loans [Abstract]
90 + days past due and still accruing		215	26
Nonaccrual		2,438	3,066
Total past due		3,630	5,695
Acquired impaired	[1]	0	0
Current		401,294	459,994
Total loans		404,924	465,689
Residential Portfolio Segment [Member] | Consumer Mortgage [Member] | Acquired Loans [Member] | Past Due 30 - 89 Days [Member]
Aged analysis of the company's loans [Abstract]
Total past due		977	2,603
Consumer Portfolio Segment [Member] | Consumer Indirect [Member]
Aged analysis of the company's loans [Abstract]
Total loans		1,098,943	1,011,978
Consumer Portfolio Segment [Member] | Consumer Indirect [Member] | Legacy Loans [Member]
Aged analysis of the company's loans [Abstract]
90 + days past due and still accruing		175	295
Nonaccrual		0	0
Total past due		12,583	14,492
Current		1,073,607	977,344
Total loans		1,086,190	991,836
Consumer Portfolio Segment [Member] | Consumer Indirect [Member] | Legacy Loans [Member] | Past Due 30 - 89 Days [Member]
Aged analysis of the company's loans [Abstract]
Total past due		12,408	14,197
Consumer Portfolio Segment [Member] | Consumer Indirect [Member] | Acquired Loans [Member]
Aged analysis of the company's loans [Abstract]
90 + days past due and still accruing		34	8
Nonaccrual		0	0
Total past due		134	253
Acquired impaired	[1]	0	0
Current		12,619	19,889
Total loans		12,753	20,142
Consumer Portfolio Segment [Member] | Consumer Indirect [Member] | Acquired Loans [Member] | Past Due 30 - 89 Days [Member]
Aged analysis of the company's loans [Abstract]
Total past due		100	245
Consumer Portfolio Segment [Member] | Consumer Direct [Member]
Aged analysis of the company's loans [Abstract]
Total loans		184,349	179,929
Consumer Portfolio Segment [Member] | Consumer Direct [Member] | Legacy Loans [Member]
Aged analysis of the company's loans [Abstract]
90 + days past due and still accruing		20	48
Nonaccrual		0	0
Total past due		1,530	1,923
Current		179,399	172,556
Total loans		180,929	174,479
Consumer Portfolio Segment [Member] | Consumer Direct [Member] | Legacy Loans [Member] | Past Due 30 - 89 Days [Member]
Aged analysis of the company's loans [Abstract]
Total past due		1,510	1,875
Consumer Portfolio Segment [Member] | Consumer Direct [Member] | Acquired Loans [Member]
Aged analysis of the company's loans [Abstract]
90 + days past due and still accruing		0	0
Nonaccrual		0	0
Total past due		74	100
Acquired impaired	[1]	0	0
Current		3,346	5,350
Total loans		3,420	5,450
Consumer Portfolio Segment [Member] | Consumer Direct [Member] | Acquired Loans [Member] | Past Due 30 - 89 Days [Member]
Aged analysis of the company's loans [Abstract]
Total past due		74	100
Consumer Portfolio Segment [Member] | Home Equity [Member]
Aged analysis of the company's loans [Abstract]
Total loans		393,950	420,329
Consumer Portfolio Segment [Member] | Home Equity [Member] | Legacy Loans [Member]
Aged analysis of the company's loans [Abstract]
90 + days past due and still accruing		371	94
Nonaccrual		1,433	1,354
Total past due		2,995	2,564
Current		311,817	319,576
Total loans		314,812	322,140
Consumer Portfolio Segment [Member] | Home Equity [Member] | Legacy Loans [Member] | Past Due 30 - 89 Days [Member]
Aged analysis of the company's loans [Abstract]
Total past due		1,191	1,116
Consumer Portfolio Segment [Member] | Home Equity [Member] | Acquired Loans [Member]
Aged analysis of the company's loans [Abstract]
90 + days past due and still accruing		14	170
Nonaccrual		1,150	1,326
Total past due		1,782	2,130
Acquired impaired	[1]	0	0
Current		77,356	96,059
Total loans		79,138	98,189
Consumer Portfolio Segment [Member] | Home Equity [Member] | Acquired Loans [Member] | Past Due 30 - 89 Days [Member]
Aged analysis of the company's loans [Abstract]
Total past due		$ 618	$ 634
[1]	Acquired impaired loans were not classified as nonperforming assets as the loans are considered to be performing under ASC 310-30. As a result interest income, through the accretion of the difference between the carrying amount of the loans and the expected cashflows, is being recognized on all acquired impaired loans.

LOANS, Amount of Business Lendi

LOANS, Amount of Business Lending Loans by Credit Quality Category (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Business Lending Loans by Credit Quality Category [Abstract]
Loans	$ 6,300,888	$ 6,256,757
Legacy Loans [Member]
Business Lending Loans by Credit Quality Category [Abstract]
Loans	4,979,836	4,619,663
Acquired Loans [Member]
Business Lending Loans by Credit Quality Category [Abstract]
Loans	1,321,052	1,637,094
Business Lending [Member]
Business Lending Loans by Credit Quality Category [Abstract]
Loans	2,403,624	2,424,223
Business Lending [Member] | Legacy Loans [Member]
Business Lending Loans by Credit Quality Category [Abstract]
Loans	1,582,807	1,376,599
Business Lending [Member] | Acquired Loans [Member]
Business Lending Loans by Credit Quality Category [Abstract]
Loans	820,817	1,047,624
Business Lending [Member] | Pass [Member]
Business Lending Loans by Credit Quality Category [Abstract]
Loans	2,134,619	2,134,137
Business Lending [Member] | Pass [Member] | Legacy Loans [Member]
Business Lending Loans by Credit Quality Category [Abstract]
Loans	1,394,290	1,170,156
Business Lending [Member] | Pass [Member] | Acquired Loans [Member]
Business Lending Loans by Credit Quality Category [Abstract]
Loans	740,329	963,981
Business Lending [Member] | Special Mention [Member]
Business Lending Loans by Credit Quality Category [Abstract]
Loans	160,550	166,397
Business Lending [Member] | Special Mention [Member] | Legacy Loans [Member]
Business Lending Loans by Credit Quality Category [Abstract]
Loans	112,777	129,076
Business Lending [Member] | Special Mention [Member] | Acquired Loans [Member]
Business Lending Loans by Credit Quality Category [Abstract]
Loans	47,773	37,321
Business Lending [Member] | Classified [Member]
Business Lending Loans by Credit Quality Category [Abstract]
Loans	101,025	111,995
Business Lending [Member] | Classified [Member] | Legacy Loans [Member]
Business Lending Loans by Credit Quality Category [Abstract]
Loans	75,740	77,367
Business Lending [Member] | Classified [Member] | Acquired Loans [Member]
Business Lending Loans by Credit Quality Category [Abstract]
Loans	25,285	34,628
Business Lending [Member] | Doubtful [Member]
Business Lending Loans by Credit Quality Category [Abstract]
Loans	1,579	1,579
Business Lending [Member] | Doubtful [Member] | Legacy Loans [Member]
Business Lending Loans by Credit Quality Category [Abstract]
Loans	0	0
Business Lending [Member] | Doubtful [Member] | Acquired Loans [Member]
Business Lending Loans by Credit Quality Category [Abstract]
Loans	1,579	1,579
Business Lending [Member] | Acquired Impaired [Member]
Business Lending Loans by Credit Quality Category [Abstract]
Loans	5,851	10,115
Business Lending [Member] | Acquired Impaired [Member] | Legacy Loans [Member]
Business Lending Loans by Credit Quality Category [Abstract]
Loans	0	0
Business Lending [Member] | Acquired Impaired [Member] | Acquired Loans [Member]
Business Lending Loans by Credit Quality Category [Abstract]
Loans	5,851	10,115
All Other Loans [Member] | Legacy Loans [Member]
Business Lending Loans by Credit Quality Category [Abstract]
Loans	3,397,029	3,243,064
All Other Loans [Member] | Acquired Loans [Member]
Business Lending Loans by Credit Quality Category [Abstract]
Loans	500,235	589,470
All Other Loans [Member] | Performing [Member] | Legacy Loans [Member]
Business Lending Loans by Credit Quality Category [Abstract]
Loans	3,383,348	3,229,051
All Other Loans [Member] | Performing [Member] | Acquired Loans [Member]
Business Lending Loans by Credit Quality Category [Abstract]
Loans	496,384	584,874
All Other Loans [Member] | Nonperforming [Member] | Legacy Loans [Member]
Business Lending Loans by Credit Quality Category [Abstract]
Loans	13,681	14,013
All Other Loans [Member] | Nonperforming [Member] | Acquired Loans [Member]
Business Lending Loans by Credit Quality Category [Abstract]
Loans	3,851	4,596
Consumer Mortgage [Member] | Legacy Loans [Member]
Business Lending Loans by Credit Quality Category [Abstract]
Loans	1,815,098	1,754,609
Consumer Mortgage [Member] | Acquired Loans [Member]
Business Lending Loans by Credit Quality Category [Abstract]
Loans	404,924	465,689
Consumer Mortgage [Member] | Performing [Member] | Legacy Loans [Member]
Business Lending Loans by Credit Quality Category [Abstract]
Loans	1,803,416	1,742,387
Consumer Mortgage [Member] | Performing [Member] | Acquired Loans [Member]
Business Lending Loans by Credit Quality Category [Abstract]
Loans	402,271	462,597
Consumer Mortgage [Member] | Nonperforming [Member] | Legacy Loans [Member]
Business Lending Loans by Credit Quality Category [Abstract]
Loans	11,682	12,222
Consumer Mortgage [Member] | Nonperforming [Member] | Acquired Loans [Member]
Business Lending Loans by Credit Quality Category [Abstract]
Loans	2,653	3,092
Consumer Indirect [Member] | Legacy Loans [Member]
Business Lending Loans by Credit Quality Category [Abstract]
Loans	1,086,190	991,836
Consumer Indirect [Member] | Acquired Loans [Member]
Business Lending Loans by Credit Quality Category [Abstract]
Loans	12,753	20,142
Consumer Indirect [Member] | Performing [Member] | Legacy Loans [Member]
Business Lending Loans by Credit Quality Category [Abstract]
Loans	1,086,015	991,541
Consumer Indirect [Member] | Performing [Member] | Acquired Loans [Member]
Business Lending Loans by Credit Quality Category [Abstract]
Loans	12,719	20,134
Consumer Indirect [Member] | Nonperforming [Member] | Legacy Loans [Member]
Business Lending Loans by Credit Quality Category [Abstract]
Loans	175	295
Consumer Indirect [Member] | Nonperforming [Member] | Acquired Loans [Member]
Business Lending Loans by Credit Quality Category [Abstract]
Loans	34	8
Consumer Direct [Member] | Legacy Loans [Member]
Business Lending Loans by Credit Quality Category [Abstract]
Loans	180,929	174,479
Consumer Direct [Member] | Acquired Loans [Member]
Business Lending Loans by Credit Quality Category [Abstract]
Loans	3,420	5,450
Consumer Direct [Member] | Performing [Member] | Legacy Loans [Member]
Business Lending Loans by Credit Quality Category [Abstract]
Loans	180,909	174,431
Consumer Direct [Member] | Performing [Member] | Acquired Loans [Member]
Business Lending Loans by Credit Quality Category [Abstract]
Loans	3,420	5,450
Consumer Direct [Member] | Nonperforming [Member] | Legacy Loans [Member]
Business Lending Loans by Credit Quality Category [Abstract]
Loans	20	48
Consumer Direct [Member] | Nonperforming [Member] | Acquired Loans [Member]
Business Lending Loans by Credit Quality Category [Abstract]
Loans	0	0
Home Equity [Member] | Legacy Loans [Member]
Business Lending Loans by Credit Quality Category [Abstract]
Loans	314,812	322,140
Home Equity [Member] | Acquired Loans [Member]
Business Lending Loans by Credit Quality Category [Abstract]
Loans	79,138	98,189
Home Equity [Member] | Performing [Member] | Legacy Loans [Member]
Business Lending Loans by Credit Quality Category [Abstract]
Loans	313,008	320,692
Home Equity [Member] | Performing [Member] | Acquired Loans [Member]
Business Lending Loans by Credit Quality Category [Abstract]
Loans	77,974	96,693
Home Equity [Member] | Nonperforming [Member] | Legacy Loans [Member]
Business Lending Loans by Credit Quality Category [Abstract]
Loans	1,804	1,448
Home Equity [Member] | Nonperforming [Member] | Acquired Loans [Member]
Business Lending Loans by Credit Quality Category [Abstract]
Loans	$ 1,164	$ 1,496

LOANS, Summary of Impaired Loan

LOANS, Summary of Impaired Loans, Excluding Purchased Impaired (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Impaired loans [Abstract]
Loans with allowance allocation	$ 3,956	$ 5,125
Loans without allowance allocation	1,151	884
Carrying balance	5,107	6,009
Contractual balance	9,688	9,165
Specifically allocated allowance	$ 956	$ 804

LOANS, Troubled Debt Restructur

LOANS, Troubled Debt Restructurings (TDRs) (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018USD ($)Loan	Sep. 30, 2017USD ($)Loan	Sep. 30, 2018USD ($)Loan	Sep. 30, 2017USD ($)Loan	Dec. 31, 2017USD ($)Loan
Troubled Debt Restructurings (TDRs) [Abstract]
TDRs, number | Loan	217		217		226
TDRs, amount	$ 5,645		$ 5,645		$ 6,135
Loans modified in TDR during the year, number | Loan	21	19	39	48
Loans modified in TDR during the year, amount	$ 322	$ 781	$ 782	$ 1,890
Maximum [Member]
Troubled Debt Restructurings (TDRs) [Abstract]
Threshold balance of TDR loans collectively included in general loan loss allocation and qualitative review	$ 500		$ 500
Nonaccrual [Member]
Troubled Debt Restructurings (TDRs) [Abstract]
TDRs, number | Loan	62		62		72
TDRs, amount	$ 2,380		$ 2,380		$ 2,728
Accruing [Member]
Troubled Debt Restructurings (TDRs) [Abstract]
TDRs, number | Loan	155		155		154
TDRs, amount	$ 3,265		$ 3,265		$ 3,407
Commercial Portfolio Segment [Member] | Minimum [Member]
Troubled Debt Restructurings (TDRs) [Abstract]
Threshold balance of loans individually evaluated for impairment	$ 500		$ 500
Commercial Portfolio Segment [Member] | Business Lending [Member]
Troubled Debt Restructurings (TDRs) [Abstract]
TDRs, number | Loan	8		8		15
TDRs, amount	$ 484		$ 484		$ 719
Loans modified in TDR during the year, number | Loan	0	1	1	4
Loans modified in TDR during the year, amount	$ 0	$ 51	$ 93	$ 414
Commercial Portfolio Segment [Member] | Business Lending [Member] | Nonaccrual [Member]
Troubled Debt Restructurings (TDRs) [Abstract]
TDRs, number | Loan	5		5		8
TDRs, amount	$ 165		$ 165		$ 218
Commercial Portfolio Segment [Member] | Business Lending [Member] | Accruing [Member]
Troubled Debt Restructurings (TDRs) [Abstract]
TDRs, number | Loan	3		3		7
TDRs, amount	$ 319		$ 319		$ 501
Residential Portfolio Segment [Member] | Consumer Mortgage [Member]
Troubled Debt Restructurings (TDRs) [Abstract]
TDRs, number | Loan	91		91		95
TDRs, amount	$ 3,783		$ 3,783		$ 4,015
Loans modified in TDR during the year, number | Loan	4	8	7	15
Loans modified in TDR during the year, amount	$ 195	$ 540	$ 407	$ 1,040
Residential Portfolio Segment [Member] | Consumer Mortgage [Member] | Nonaccrual [Member]
Troubled Debt Restructurings (TDRs) [Abstract]
TDRs, number | Loan	45		45		51
TDRs, amount	$ 2,000		$ 2,000		$ 2,265
Residential Portfolio Segment [Member] | Consumer Mortgage [Member] | Accruing [Member]
Troubled Debt Restructurings (TDRs) [Abstract]
TDRs, number | Loan	46		46		44
TDRs, amount	$ 1,783		$ 1,783		$ 1,750
Consumer Portfolio Segment [Member] | Consumer Indirect [Member]
Troubled Debt Restructurings (TDRs) [Abstract]
TDRs, number | Loan	76		76		71
TDRs, amount	$ 814		$ 814		$ 883
Loans modified in TDR during the year, number | Loan	14	8	24	22
Loans modified in TDR during the year, amount	$ 117	$ 181	$ 176	$ 323
Consumer Portfolio Segment [Member] | Consumer Indirect [Member] | Nonaccrual [Member]
Troubled Debt Restructurings (TDRs) [Abstract]
TDRs, number | Loan	0		0		0
TDRs, amount	$ 0		$ 0		$ 0
Consumer Portfolio Segment [Member] | Consumer Indirect [Member] | Accruing [Member]
Troubled Debt Restructurings (TDRs) [Abstract]
TDRs, number | Loan	76		76		71
TDRs, amount	$ 814		$ 814		$ 883
Consumer Portfolio Segment [Member] | Consumer Direct [Member]
Troubled Debt Restructurings (TDRs) [Abstract]
TDRs, number | Loan	22		22		25
TDRs, amount	$ 70		$ 70		$ 69
Loans modified in TDR during the year, number | Loan	2	1	5	4
Loans modified in TDR during the year, amount	$ 10	$ 1	$ 21	$ 7
Consumer Portfolio Segment [Member] | Consumer Direct [Member] | Nonaccrual [Member]
Troubled Debt Restructurings (TDRs) [Abstract]
TDRs, number | Loan	0		0		0
TDRs, amount	$ 0		$ 0		$ 0
Consumer Portfolio Segment [Member] | Consumer Direct [Member] | Accruing [Member]
Troubled Debt Restructurings (TDRs) [Abstract]
TDRs, number | Loan	22		22		25
TDRs, amount	$ 70		$ 70		$ 69
Consumer Portfolio Segment [Member] | Home Equity [Member]
Troubled Debt Restructurings (TDRs) [Abstract]
TDRs, number | Loan	20		20		20
TDRs, amount	$ 494		$ 494		$ 449
Loans modified in TDR during the year, number | Loan	1	1	2	3
Loans modified in TDR during the year, amount	$ 0	$ 8	$ 85	$ 106
Consumer Portfolio Segment [Member] | Home Equity [Member] | Nonaccrual [Member]
Troubled Debt Restructurings (TDRs) [Abstract]
TDRs, number | Loan	12		12		13
TDRs, amount	$ 215		$ 215		$ 245
Consumer Portfolio Segment [Member] | Home Equity [Member] | Accruing [Member]
Troubled Debt Restructurings (TDRs) [Abstract]
TDRs, number | Loan	8		8		7
TDRs, amount	$ 279		$ 279		$ 204

LOANS, Allowance for Loan Losse

LOANS, Allowance for Loan Losses (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Allowance for loan losses [Roll Forward]
Beginning balance	$ 49,618	$ 47,451	$ 47,583	$ 47,233
Charge-offs	(3,267)	(3,224)	(10,636)	(9,447)
Recoveries	1,567	1,442	4,844	4,594
Provision	2,215	2,314	8,342	5,603
Ending balance	50,133	47,983	50,133	47,983
Acquired Impaired [Member]
Allowance for loan losses [Roll Forward]
Beginning balance	33	63	147	108
Charge-offs	0	0	(368)	(184)
Recoveries	0	0	0	0
Provision	15	(11)	269	128
Ending balance	48	52	48	52
Residential Portfolio Segment [Member] | Business Lending [Member]
Allowance for loan losses [Roll Forward]
Beginning balance	18,439	17,230	17,257	17,220
Charge-offs	(73)	(124)	(2,000)	(1,062)
Recoveries	93	127	404	481
Provision	321	399	3,119	993
Ending balance	18,780	17,632	18,780	17,632
Commercial Portfolio Segment [Member] | Consumer Mortgage [Member]
Allowance for loan losses [Roll Forward]
Beginning balance	10,473	10,197	10,465	10,094
Charge-offs	(144)	(198)	(588)	(541)
Recoveries	46	24	109	42
Provision	(205)	280	184	708
Ending balance	10,170	10,303	10,170	10,303
Consumer Portfolio Segment [Member] | Consumer Indirect [Member]
Allowance for loan losses [Roll Forward]
Beginning balance	14,424	13,918	13,468	13,782
Charge-offs	(2,364)	(2,328)	(6,031)	(5,969)
Recoveries	1,190	1,058	3,688	3,379
Provision	1,719	1,130	3,844	2,586
Ending balance	14,969	13,778	14,969	13,778
Consumer Portfolio Segment [Member] | Consumer Direct [Member]
Allowance for loan losses [Roll Forward]
Beginning balance	3,164	2,945	3,039	2,979
Charge-offs	(465)	(574)	(1,324)	(1,463)
Recoveries	223	221	612	648
Provision	299	426	894	854
Ending balance	3,221	3,018	3,221	3,018
Consumer Portfolio Segment [Member] | Home Equity [Member]
Allowance for loan losses [Roll Forward]
Beginning balance	2,015	2,242	2,107	2,399
Charge-offs	(221)	0	(325)	(228)
Recoveries	15	12	31	44
Provision	225	(52)	221	(13)
Ending balance	2,034	2,202	2,034	2,202
Unallocated Financing Receivables [Member]
Allowance for loan losses [Roll Forward]
Beginning balance	1,070	856	1,100	651
Charge-offs	0	0	0	0
Recoveries	0	0	0	0
Provision	(159)	142	(189)	347
Ending balance	$ 911	$ 998	$ 911	$ 998

GOODWILL AND IDENTIFIABLE INT_3

GOODWILL AND IDENTIFIABLE INTANGIBLE ASSETS (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Dec. 31, 2017
Identifiable Intangible Assets [Abstract]
Gross carrying amount	$ 150,518	$ 149,437
Accumulated amortization	(72,297)	(58,779)
Net carrying amount	78,221	90,658
Estimated aggregate amortization expense for each of five succeeding fiscal years [Abstract]
Oct - Dec 2018	4,375
2,019	15,296
2,020	12,722
2,021	10,853
2,022	9,317
Thereafter	25,658
Net carrying amount	78,221	90,658
Components of goodwill [Abstract]
Goodwill, beginning of period	739,254
Goodwill, activity	(951)
Goodwill, end of period	738,303
Accumulated impairment, beginning of period	(4,824)
Accumulated impairment, activity	0
Accumulated impairment, end of period	(4,824)
Goodwill, net, beginning of period	734,430
Goodwill, net, activity	(951)
Goodwill, net, end of period	733,479
Core Deposit Intangibles [Member]
Identifiable Intangible Assets [Abstract]
Gross carrying amount	62,902	62,902
Accumulated amortization	(42,790)	(37,877)
Net carrying amount	20,112	25,025
Estimated aggregate amortization expense for each of five succeeding fiscal years [Abstract]
Net carrying amount	20,112	25,025
Other Intangibles [Member]
Identifiable Intangible Assets [Abstract]
Gross carrying amount	87,616	86,535
Accumulated amortization	(29,507)	(20,902)
Net carrying amount	58,109	65,633
Estimated aggregate amortization expense for each of five succeeding fiscal years [Abstract]
Net carrying amount	$ 58,109	$ 65,633

MANDATORILY REDEEMABLE PREFER_3

MANDATORILY REDEEMABLE PREFERRED SECURITIES (Details) $ in Millions	Jul. 31, 2018USD ($)	Sep. 30, 2018USD ($)Trust
Mandatorily Redeemable Preferred Securities [Abstract]
Number of unconsolidated subsidiary business trusts owned | Trust		2
Percent ownership of unconsolidated subsidiary trusts		100.00%
Community Statutory Trust III [Member]
Mandatorily Redeemable Preferred Securities [Abstract]
Redemption of debentures and associated preferred securities	$ 25.2
Preferred Debt [Member] | Community Capital Trust IV [Member]
Terms of preferred securities for each trust [Abstract]
Issuance date		Dec. 8, 2006
Par amount		$ 75
Variable interest rate basis		3 month LIBOR
Effective interest rate		3.98%
Maturity date		Dec. 15, 2036
Call price		Par
Preferred Debt [Member] | Community Capital Trust IV [Member] | LIBOR [Member]
Terms of preferred securities for each trust [Abstract]
Term of variable rate		3 months
Variable interest rate, basis spread		1.65%
Preferred Debt [Member] | MBVT Statutory Trust I [Member]
Terms of preferred securities for each trust [Abstract]
Issuance date		Dec. 15, 2004
Par amount		$ 20.6
Variable interest rate basis		3 month LIBOR
Effective interest rate		4.28%
Maturity date		Dec. 31, 2034
Call price		Par
Preferred Debt [Member] | MBVT Statutory Trust I [Member] | LIBOR [Member]
Terms of preferred securities for each trust [Abstract]
Term of variable rate		3 months
Variable interest rate, basis spread		1.95%

BENEFIT PLANS (Details)

BENEFIT PLANS (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	May 12, 2017	Dec. 31, 2016
Pension Benefits [Member]
Pension Plans [Abstract]
Unamortized actuarial gain					$ 1,900
Discount rate					4.40%	4.50%
Net periodic benefit cost [Abstract]
Service cost	$ 1,154	$ 1,037	$ 3,396	$ 3,143
Interest cost	1,422	1,453	4,251	4,265
Expected return on plan assets	(3,705)	(3,448)	(11,115)	(9,977)
Amortization of unrecognized net loss	299	148	895	619
Amortization of prior service cost	(60)	13	(225)	43
Net periodic benefit cost (income)	(890)	(797)	(2,798)	(1,907)
Pension Benefits [Member] | Nonqualified Plan [Member] | Unfunded Plan [Member]
Pension Plans [Abstract]
Unfunded initial projected benefit obligation	800		800
Post-retirement Benefits [Member]
Net periodic benefit cost [Abstract]
Service cost	0	0	0	0
Interest cost	18	19	52	57
Expected return on plan assets	0	0	0	0
Amortization of unrecognized net loss	5	2	15	6
Amortization of prior service cost	(45)	(45)	(134)	(134)
Net periodic benefit cost (income)	$ (22)	$ (24)	$ (67)	$ (71)

EARNINGS PER SHARE (Details)

EARNINGS PER SHARE (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
EARNINGS PER SHARE [Abstract]
Weighted-average anti-dilutive stock options outstanding (in shares)	400,000	200,000	400,000	100,000
Basic earnings per share [Abstract]
Net income	$ 43,106	$ 35,243	$ 127,818	$ 78,691
Income attributable to unvested stock-based compensation awards	(191)	(164)	(563)	(387)
Income available to common shareholders	$ 42,915	$ 35,079	$ 127,255	$ 78,304
Weighted-average common shares outstanding - basic (in shares)	51,250,000	50,703,000	51,108,000	48,189,000
Basic earnings per share (in dollars per share)	$ 0.84	$ 0.69	$ 2.49	$ 1.62
Diluted earnings per share [Abstract]
Net income	$ 43,106	$ 35,243	$ 127,818	$ 78,691
Income attributable to unvested stock-based compensation awards	(191)	(164)	(563)	(387)
Income available to common shareholders	$ 42,915	$ 35,079	$ 127,255	$ 78,304
Weighted-average common shares outstanding - basic (in shares)	51,250,000	50,703,000	51,108,000	48,189,000
Assumed exercise of stock options (in shares)	608,000	585,000	590,000	640,000
Weighted-average common shares outstanding - diluted (in shares)	51,858,000	51,288,000	51,698,000	48,829,000
Diluted earnings per share (in dollars per share)	$ 0.83	$ 0.68	$ 2.46	$ 1.60
Stock Repurchase Program [Abstract]
Number of common shares authorized to be repurchased (in shares)					2,500,000
Number of common shares repurchased (in shares)			0

COMMITMENTS, CONTINGENT LIABI_3

COMMITMENTS, CONTINGENT LIABILITIES AND RESTRICTIONS (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Commitments, Contingent Liabilities and Restrictions [Abstract]
Contract amount of commitments and contingencies	$ 1,129,669	$ 1,103,786
Minimum [Member]
Commitments, Contingent Liabilities and Restrictions [Abstract]
Range of reasonably possible losses for such matters in the aggregate, beyond the existing recorded liability	0
Maximum [Member]
Commitments, Contingent Liabilities and Restrictions [Abstract]
Range of reasonably possible losses for such matters in the aggregate, beyond the existing recorded liability	1,000
Commitments to Extend Credit [Member]
Commitments, Contingent Liabilities and Restrictions [Abstract]
Contract amount of commitments and contingencies	1,097,509	1,080,004
Standby Letters of Credit [Member]
Commitments, Contingent Liabilities and Restrictions [Abstract]
Contract amount of commitments and contingencies	$ 32,160	$ 23,782

FAIR VALUE, Financial Assets an

FAIR VALUE, Financial Assets and Liabilities Accounted for at Fair Value On a Recurring Basis (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Available-for-sale investment securities [Abstract]
Available-for-sale investment securities	$ 2,904,779
Equity securities	498	$ 0
Marketable equity securities	0	526
Available-for-sale investment securities	2,904,779	3,031,088
Derivative asset	9	89
U.S. Treasury and Agency Securities [Member]
Available-for-sale investment securities [Abstract]
Available-for-sale investment securities	1,998,095	2,054,071
Obligations of State and Political Subdivisions [Member]
Available-for-sale investment securities [Abstract]
Available-for-sale investment securities	475,365	528,956
Government Agency Mortgage-Backed Securities [Member]
Available-for-sale investment securities [Abstract]
Available-for-sale investment securities	358,063	357,538
Corporate Debt Securities [Member]
Available-for-sale investment securities [Abstract]
Available-for-sale investment securities	2,550	2,623
Government Agency Collateralized Mortgage Obligations [Member]
Available-for-sale investment securities [Abstract]
Available-for-sale investment securities	70,706	87,374
Recurring [Member]
Available-for-sale investment securities [Abstract]
Available-for-sale investment securities	2,904,779
Equity securities	498
Marketable equity securities		526
Available-for-sale investment securities		3,031,088
Mortgage loans held for sale	0	461
Total	2,905,241	3,031,802
Recurring [Member] | Commitments to Originate Real Estate Loans for Sale [Member]
Available-for-sale investment securities [Abstract]
Derivative asset	9	89
Recurring [Member] | Forward Sales Commitments [Member]
Available-for-sale investment securities [Abstract]
Derivative asset	9	4
Recurring [Member] | Interest Rate Swap Agreements [Member]
Available-for-sale investment securities [Abstract]
Derivative asset	1,306	1,064
Derivative liability	(1,360)	(904)
Recurring [Member] | U.S. Treasury and Agency Securities [Member]
Available-for-sale investment securities [Abstract]
Available-for-sale investment securities	1,998,095	2,054,071
Recurring [Member] | Obligations of State and Political Subdivisions [Member]
Available-for-sale investment securities [Abstract]
Available-for-sale investment securities	475,365	528,956
Recurring [Member] | Government Agency Mortgage-Backed Securities [Member]
Available-for-sale investment securities [Abstract]
Available-for-sale investment securities	358,063	357,538
Recurring [Member] | Corporate Debt Securities [Member]
Available-for-sale investment securities [Abstract]
Available-for-sale investment securities	2,550	2,623
Recurring [Member] | Government Agency Collateralized Mortgage Obligations [Member]
Available-for-sale investment securities [Abstract]
Available-for-sale investment securities	70,706	87,374
Recurring [Member] | Level 1 [Member]
Available-for-sale investment securities [Abstract]
Available-for-sale investment securities	1,867,144
Equity securities	498
Marketable equity securities		526
Available-for-sale investment securities		1,909,816
Mortgage loans held for sale	0	0
Total	1,867,642	1,909,816
Recurring [Member] | Level 1 [Member] | Commitments to Originate Real Estate Loans for Sale [Member]
Available-for-sale investment securities [Abstract]
Derivative asset	0	0
Recurring [Member] | Level 1 [Member] | Forward Sales Commitments [Member]
Available-for-sale investment securities [Abstract]
Derivative asset	0	0
Recurring [Member] | Level 1 [Member] | Interest Rate Swap Agreements [Member]
Available-for-sale investment securities [Abstract]
Derivative asset	0	0
Derivative liability	0	0
Recurring [Member] | Level 1 [Member] | U.S. Treasury and Agency Securities [Member]
Available-for-sale investment securities [Abstract]
Available-for-sale investment securities	1,867,144	1,909,290
Recurring [Member] | Level 1 [Member] | Obligations of State and Political Subdivisions [Member]
Available-for-sale investment securities [Abstract]
Available-for-sale investment securities	0	0
Recurring [Member] | Level 1 [Member] | Government Agency Mortgage-Backed Securities [Member]
Available-for-sale investment securities [Abstract]
Available-for-sale investment securities	0	0
Recurring [Member] | Level 1 [Member] | Corporate Debt Securities [Member]
Available-for-sale investment securities [Abstract]
Available-for-sale investment securities	0	0
Recurring [Member] | Level 1 [Member] | Government Agency Collateralized Mortgage Obligations [Member]
Available-for-sale investment securities [Abstract]
Available-for-sale investment securities	0	0
Recurring [Member] | Level 2 [Member]
Available-for-sale investment securities [Abstract]
Available-for-sale investment securities	1,037,635
Equity securities	0
Marketable equity securities		0
Available-for-sale investment securities		1,121,272
Mortgage loans held for sale	0	461
Total	1,037,590	1,121,897
Mortgage loans held for sale, at principal value	0
Recurring [Member] | Level 2 [Member] | Commitments to Originate Real Estate Loans for Sale [Member]
Available-for-sale investment securities [Abstract]
Derivative asset	0	0
Recurring [Member] | Level 2 [Member] | Forward Sales Commitments [Member]
Available-for-sale investment securities [Abstract]
Derivative asset	9	4
Recurring [Member] | Level 2 [Member] | Interest Rate Swap Agreements [Member]
Available-for-sale investment securities [Abstract]
Derivative asset	1,306	1,064
Derivative liability	(1,360)	(904)
Recurring [Member] | Level 2 [Member] | U.S. Treasury and Agency Securities [Member]
Available-for-sale investment securities [Abstract]
Available-for-sale investment securities	130,951	144,781
Recurring [Member] | Level 2 [Member] | Obligations of State and Political Subdivisions [Member]
Available-for-sale investment securities [Abstract]
Available-for-sale investment securities	475,365	528,956
Recurring [Member] | Level 2 [Member] | Government Agency Mortgage-Backed Securities [Member]
Available-for-sale investment securities [Abstract]
Available-for-sale investment securities	358,063	357,538
Recurring [Member] | Level 2 [Member] | Corporate Debt Securities [Member]
Available-for-sale investment securities [Abstract]
Available-for-sale investment securities	2,550	2,623
Recurring [Member] | Level 2 [Member] | Government Agency Collateralized Mortgage Obligations [Member]
Available-for-sale investment securities [Abstract]
Available-for-sale investment securities	70,706	87,374
Recurring [Member] | Level 3 [Member]
Available-for-sale investment securities [Abstract]
Available-for-sale investment securities	0
Equity securities	0
Marketable equity securities		0
Available-for-sale investment securities		0
Mortgage loans held for sale	0	0
Total	9	89
Recurring [Member] | Level 3 [Member] | Commitments to Originate Real Estate Loans for Sale [Member]
Available-for-sale investment securities [Abstract]
Derivative asset	9	89
Recurring [Member] | Level 3 [Member] | Forward Sales Commitments [Member]
Available-for-sale investment securities [Abstract]
Derivative asset	0	0
Recurring [Member] | Level 3 [Member] | Interest Rate Swap Agreements [Member]
Available-for-sale investment securities [Abstract]
Derivative asset	0	0
Derivative liability	0	0
Recurring [Member] | Level 3 [Member] | U.S. Treasury and Agency Securities [Member]
Available-for-sale investment securities [Abstract]
Available-for-sale investment securities	0	0
Recurring [Member] | Level 3 [Member] | Obligations of State and Political Subdivisions [Member]
Available-for-sale investment securities [Abstract]
Available-for-sale investment securities	0	0
Recurring [Member] | Level 3 [Member] | Government Agency Mortgage-Backed Securities [Member]
Available-for-sale investment securities [Abstract]
Available-for-sale investment securities	0	0
Recurring [Member] | Level 3 [Member] | Corporate Debt Securities [Member]
Available-for-sale investment securities [Abstract]
Available-for-sale investment securities	0	0
Recurring [Member] | Level 3 [Member] | Government Agency Collateralized Mortgage Obligations [Member]
Available-for-sale investment securities [Abstract]
Available-for-sale investment securities	$ 0	$ 0

FAIR VALUE, Assets and Liabilit

FAIR VALUE, Assets and Liabilities Measured on Nonrecurring Basis (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Assets and Liabilities Measured on Nonrecurring Basis [Abstract]
Other real estate owned	$ 1,142	$ 1,915
Valuation allowance	956	804
Mortgage Servicing Rights [Member]
Assets and Liabilities Measured on Nonrecurring Basis [Abstract]
Valuation allowance	0
Non-recurring [Member]
Assets and Liabilities Measured on Nonrecurring Basis [Abstract]
Other real estate owned	1,142	1,915
Non-recurring [Member] | Level 1 [Member]
Assets and Liabilities Measured on Nonrecurring Basis [Abstract]
Other real estate owned	0	0
Non-recurring [Member] | Level 2 [Member]
Assets and Liabilities Measured on Nonrecurring Basis [Abstract]
Other real estate owned	0	0
Non-recurring [Member] | Level 3 [Member]
Assets and Liabilities Measured on Nonrecurring Basis [Abstract]
Other real estate owned	$ 1,142	$ 1,915

FAIR VALUE, Significant Unobser

FAIR VALUE, Significant Unobservable Inputs (Details) $ in Thousands	Sep. 30, 2018USD ($)	Dec. 31, 2017USD ($)
Significant Unobservable Inputs used in determination of Fair Value of Assets Classified as Level 3 [Abstract]
Other real estate owned	$ 1,142	$ 1,915
Other real estate owned, Valuation Technique [Extensible List]	us-gaap:MarketApproachValuationTechniqueMember	us-gaap:MarketApproachValuationTechniqueMember
Other real estate owned, Measurement Input [Extensible List]	us-gaap:MeasurementInputCostToSellMember	us-gaap:MeasurementInputCostToSellMember
Commitments to originate real estate loans for sale	$ 9	$ 89
Commitments to originate real estate loans for sale, Valuation Technique [Extensible List]	us-gaap:ValuationTechniqueDiscountedCashFlowMember	us-gaap:ValuationTechniqueDiscountedCashFlowMember
Commitments to originate real estate loans for sale, measurement input	0.01	0.01
Minimum [Member]
Significant Unobservable Inputs used in determination of Fair Value of Assets Classified as Level 3 [Abstract]
Other real estate owned, measurement input	0.090	0.090
Maximum [Member]
Significant Unobservable Inputs used in determination of Fair Value of Assets Classified as Level 3 [Abstract]
Other real estate owned, measurement input	0.763	0.990
Weighted Average [Member]
Significant Unobservable Inputs used in determination of Fair Value of Assets Classified as Level 3 [Abstract]
Other real estate owned, measurement input	0.323	0.385

FAIR VALUE, Carrying Amounts an

FAIR VALUE, Carrying Amounts and Estimated Fair Values of Other Financial Instruments (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Carrying Value [Member]
Financial assets [Abstract]
Net loans	$ 6,250,755	$ 6,209,174
Financial liabilities [Abstract]
Deposits	8,463,821	8,444,420
Short-term borrowings	0	24,000
Securities sold under agreement to repurchase, short-term	274,561	337,011
Other long-term debt	1,998	2,071
Subordinated debt held by unconsolidated subsidiary trusts	97,939	122,814
Fair Value [Member]
Financial assets [Abstract]
Net loans	6,171,599	6,244,941
Financial liabilities [Abstract]
Deposits	8,441,535	8,431,481
Short-term borrowings	0	24,000
Securities sold under agreement to repurchase, short-term	274,561	337,011
Other long-term debt	1,915	2,021
Subordinated debt held by unconsolidated subsidiary trusts	$ 97,939	$ 122,814

DERIVATIVE INSTRUMENTS (Details

DERIVATIVE INSTRUMENTS (Details) - Interest Rate Swap [Member] $ in Thousands	9 Months Ended
	Sep. 30, 2018USD ($)
Derivative Instruments [Abstract]
Derivative, notional amount	$ 37,500
Derivative weighted average receive rate	4.06%
Derivative weighted average pay rate	3.84%
Weighted average maturity period	5 years 8 months 12 days
Other Assets [Member]
Derivative Instruments [Abstract]
Fair value of derivate assets	$ 1,300
Other Liabilities [Member]
Derivative Instruments [Abstract]
Fair value of derivate liability	1,300
Designated as Hedging Instrument [Member] | Fair Value Hedging [Member]
Derivative Instruments [Abstract]
Derivative, notional amount	$ 6,600
Derivative weighted average receive rate	2.74%
Derivative weighted average pay rate	3.11%
Weighted average maturity period	14 years 9 months 18 days
Designated as Hedging Instrument [Member] | Fair Value Hedging [Member] | Other Liabilities [Member]
Derivative Instruments [Abstract]
Fair value of derivate liability	$ 50

SEGMENT INFORMATION (Details)

SEGMENT INFORMATION (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Information about reportable segments [Abstract]
Net interest income	$ 86,198	$ 84,395	$ 257,668	$ 229,698
Provision for loan losses	2,215	2,314	8,342	5,603
Noninterest revenues	55,791	52,941	169,841	148,485
Amortization of intangible assets	4,427	4,949	13,780	11,980
Acquisition expenses	(832)	580	(769)	25,192
Other operating expenses	81,638	78,247	244,665	223,058
Income before income taxes	54,541	51,246	161,491	112,350
Assets	10,659,567	10,850,218	10,659,567	10,850,218	$ 10,746,198
Goodwill	733,479	731,505	733,479	731,505	$ 734,430
Eliminations [Member]
Information about reportable segments [Abstract]
Net interest income	0	0	0	0
Provision for loan losses	0	0	0	0
Noninterest revenues	(763)	(684)	(2,159)	(2,035)
Amortization of intangible assets	0	0	0	0
Acquisition expenses	0	0	0	0
Other operating expenses	(763)	(684)	(2,159)	(2,035)
Income before income taxes	0	0	0	0
Assets	(53,200)	(67,461)	(53,200)	(67,461)
Goodwill	0	0	0	0
Banking [Member] | Operating Segments [Member]
Information about reportable segments [Abstract]
Net interest income	86,060	84,227	257,313	229,233
Provision for loan losses	2,215	2,314	8,342	5,603
Noninterest revenues	18,002	20,120	58,399	54,049
Amortization of intangible assets	1,535	1,796	4,914	3,520
Acquisition expenses	(832)	534	(782)	23,784
Other operating expenses	57,863	56,926	172,283	160,311
Income before income taxes	43,281	42,777	130,955	90,064
Assets	10,440,732	10,613,065	10,440,732	10,613,065
Goodwill	629,916	629,153	629,916	629,153
Employee Benefit Services [Member] | Operating Segments [Member]
Information about reportable segments [Abstract]
Net interest income	102	104	264	276
Provision for loan losses	0	0	0	0
Noninterest revenues	23,815	21,207	70,316	59,961
Amortization of intangible assets	1,970	2,323	6,047	6,256
Acquisition expenses	0	11	7	1,190
Other operating expenses	14,025	12,788	41,938	37,225
Income before income taxes	7,922	6,189	22,588	15,566
Assets	205,565	226,812	205,565	226,812
Goodwill	83,275	84,448	83,275	84,448
All Other [Member] | Operating Segments [Member]
Information about reportable segments [Abstract]
Net interest income	36	64	91	189
Provision for loan losses	0	0	0	0
Noninterest revenues	14,737	12,298	43,285	36,510
Amortization of intangible assets	922	830	2,819	2,204
Acquisition expenses	0	35	6	218
Other operating expenses	10,513	9,217	32,603	27,557
Income before income taxes	3,338	2,280	7,948	6,720
Assets	66,470	77,802	66,470	77,802
Goodwill	$ 20,288	$ 17,904	$ 20,288	$ 17,904