Community Bank System (CBU) 10-K 1 Mar 22 2021 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2021	Jan. 31, 2022	Jun. 30, 2021
Cover [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2021
Current Fiscal Year End Date	--12-31
Document Transition Report	false
Entity Registrant Name	COMMUNITY BANK SYSTEM, INC.
Entity Incorporation, State or Country Code	DE
Entity File Number	001-13695
Entity Tax Identification Number	16-1213679
Entity Address, Address Line One	5790 Widewaters Parkway
Entity Address, City or Town	DeWitt
Entity Address, State or Province	NY
Entity Address, Postal Zip Code	13214
City Area Code	315
Local Phone Number	445-2282
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Filer Category	Large Accelerated Filer
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Small Business	false
Entity Public Float			$ 4,022,854,197
Entity Common Stock, Shares Outstanding		53,864,500
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	FY
Entity Central Index Key	0000723188
Document Annual Report	true
Title of 12(b) Security	Common Stock, $1.00 par value per share
Trading Symbol	CBU
Security Exchange Name	NYSE
ICFR Auditor Attestation Flag	true
Auditor Name	PricewaterhouseCoopers LLP
Auditor Firm ID	238
Auditor Location	New York

CONSOLIDATED STATEMENTS OF COND

CONSOLIDATED STATEMENTS OF CONDITION - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Assets:
Cash and cash equivalents	$ 1,875,064	$ 1,645,805
Available-for-sale investment securities (cost of $4,980,102 and $3,427,779 respectively)	4,934,210	3,547,892
vailable-for-sale investment securities (cost of $4,980,102 and $3,427,779 respectively)	44,879	47,455
Loans held for sale, at fair value	0	1,622
Loans	7,373,639	7,415,952
Allowance for credit losses	(49,869)	(60,869)
Net loans	7,323,770	7,355,083
Goodwill, net	799,109	793,708
Core deposit intangibles, net	9,087	13,831
Other intangibles, net	56,139	39,109
Intangible assets, net	864,335	846,648
Premises and equipment, net	160,651	165,655
Accrued interest and fees receivable	35,894	39,031
Other assets	313,854	281,903
Total assets	15,552,657	13,931,094
Liabilities:
Noninterest-bearing deposits	3,921,663	3,361,768
Interest-bearing deposits	8,989,505	7,863,206
Total deposits	12,911,168	11,224,974
Securities sold under agreement to repurchase, short-term	324,720	284,008
Other Federal Home Loan Bank borrowings	1,888	6,658
Subordinated notes payable	3,277	3,303
Subordinated debt held by unconsolidated subsidiary trusts	0	77,320
Accrued interest and other liabilities	210,797	230,724
Total liabilities	13,451,850	11,826,987
Commitments and contingencies (See Note N)
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; 54,092,421 and 53,754,599 shares issued, respectively	54,092	53,755
Additional paid-in capital	1,041,304	1,025,163
Retained earnings	1,058,286	960,183
Accumulated other comprehensive (loss) income	(50,627)	62,077
Treasury stock, at cost (214,374 shares including 146,860 shares held by deferred compensation arrangements at December 31, 2021, and 161,472 shares including 161,457 shares held by deferred compensation arrangements at December 31, 2020)	(10,610)	(6,198)
Deferred compensation arrangements (146,860 shares at December 31, 2021 and 161,457 shares at December 31, 2020)	8,362	9,127
Total shareholders' equity	2,100,807	2,104,107
Total liabilities and shareholders' equity	$ 15,552,657	$ 13,931,094

CONSOLIDATED STATEMENTS OF CO_2

CONSOLIDATED STATEMENTS OF CONDITION (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Assets:
Available-for-sale investment securities, cost	$ 4,980,102	$ 3,427,779
Equity and other securities, cost	$ 43,917	$ 46,511
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)	54,092,421	53,754,599
Treasury stock, shares at cost (in shares)	214,374	161,472
Shares held by deferred compensation arrangements (in shares)	146,860	161,457

CONSOLIDATED STATEMENTS OF INCO

CONSOLIDATED STATEMENTS OF INCOME - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Interest income:
Interest and fees on loans	$ 308,355	$ 314,779	$ 308,210
Interest and dividends on taxable investments	68,607	62,538	65,904
Interest and dividends on nontaxable investments	10,458	11,961	11,613
Total interest income	387,420	389,278	385,727
Interest expense:
Interest on deposits	11,631	16,761	20,460
Interest on borrowings	930	1,569	1,848
Interest on subordinated notes payable	154	670	346
Interest on subordinated debt held by unconsolidated subsidiary trusts	293	1,875	3,898
Total interest expense	13,008	20,875	26,552
Net interest income	374,412	368,403	359,175
Provision for credit losses	(8,839)	14,212	8,430
Net interest income after provision for credit losses	383,251	354,191	350,745
Noninterest revenues:
Deposit service fees	59,212	57,370	65,602
Mortgage banking	1,772	5,301	523
Other banking services	3,674	3,753	4,358
Employee benefit services	114,328	101,329	97,167
Insurance services	33,992	32,372	32,199
Wealth management services	33,240	27,879	25,869
Unrealized gain (loss) on equity securities	17	(6)	19
Gain on debt extinguishment	0	421	0
Gain on sales of investment securities, net	0	0	4,882
Total noninterest revenues	246,235	228,419	230,619
Noninterest expenses:
Salaries and employee benefits	241,501	228,384	219,916
Occupancy and equipment	41,240	40,732	39,850
Data processing and communications	51,003	45,755	41,407
Amortization of intangible assets	14,051	14,297	15,956
Legal and professional fees	11,723	11,605	10,783
Business development and marketing	9,319	9,463	11,416
Litigation accrual	(100)	2,950	0
Acquisition expenses	701	4,933	8,608
Acquisition-related contingent consideration adjustment	200	0	0
Other expenses	18,500	18,415	24,090
Total noninterest expenses	388,138	376,534	372,026
Income before income taxes	241,348	206,076	209,338
Income taxes	51,654	41,400	40,275
Net income	$ 189,694	$ 164,676	$ 169,063
Basic earnings per share (in dollars per share)	$ 3.51	$ 3.10	$ 3.26
Diluted earnings per share (in dollars per share)	$ 3.48	$ 3.08	$ 3.23

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Pension and other post retirement obligations:
Amortization of actuarial gains (losses) included in net periodic pension cost, gross	$ 17,443	$ 8,379	$ (2,563)
Tax effect	(4,192)	(2,012)	605
Amortization of actuarial gains (losses) included in net periodic pension cost, net	13,251	6,367	(1,958)
Amortization of prior service cost included in net periodic pension cost, gross	200	(471)	(115)
Tax effect	(48)	113	28
Amortization of prior service cost included in net periodic pension cost, net	152	(358)	(87)
Other comprehensive income (loss) related to pension and other post retirement obligations, net of taxes	13,403	6,009	(2,045)
Unrealized gains (losses) on available-for-sale securities:
Net unrealized holding (losses) gains arising during period, gross	(166,007)	87,237	53,988
Tax effect	39,900	(20,943)	(13,176)
Net unrealized holding (losses) gains arising during period, net	(126,107)	66,294	40,812
Reclassification adjustment for net (gains) included in net income, gross	0	0	(4,882)
Tax effect	0	0	1,194
Reclassification adjustment for net (gains) included in net income, net	0	0	(3,688)
Other comprehensive (loss) gain related to unrealized (losses) gains on available-for-sale securities, net of taxes	(126,107)	66,294	37,124
Other comprehensive (loss) income, net of tax	(112,704)	72,303	35,079
Net income	189,694	164,676	169,063
Comprehensive income	76,990	236,979	204,142
Accumulated Other Comprehensive (Loss) Income By Component:
Unrealized (loss) for pension and other postretirement obligations	(20,624)	(38,267)	(46,175)
Tax effect	5,154	9,394	11,293
Net unrealized (loss) for pension and other postretirement obligations	(15,470)	(28,873)	(34,882)
Unrealized (loss) gain on available-for-sale securities	(45,893)	120,114	32,877
Tax effect	10,736	(29,164)	(8,221)
Net unrealized (loss) gain on available-for-sale securities	(35,157)	90,950	24,656
Accumulated other comprehensive (loss) income	$ (50,627)	$ 62,077	$ (10,226)

CONSOLIDATED STATEMENTS OF CHAN

CONSOLIDATED STATEMENTS OF CHANGES IN SHAREHOLDERS' EQUITY - USD ($) $ in Thousands	Common Stock Shares Outstanding [Member]	Common Stock Amount Issued [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive (Loss)/Income [Member]	Treasury Stock [Member]	Deferred Compensation Arrangements [Member]	Total
Balance at Dec. 31, 2018		$ 51,577	$ 911,748	$ 795,563	$ (45,305)	$ (11,528)	$ 11,728	$ 1,713,783
Balance (in shares) at Dec. 31, 2018	51,257,824
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income				169,063				169,063
Other comprehensive income (loss), net of tax					35,079			35,079
Cash dividends declared:
Common				(81,775)				(81,775)
Common stock activity under employee stock ownership plans		398	6,517					6,915
Common stock activity under employee stock ownership plans (in shares)	397,887
Stock-based compensation			5,285					5,285
Distribution of stock under deferred compensation arrangements			1,064			830	(1,894)	0
Distribution of stock under deferred compensation arrangements (in shares)	32,431
Treasury stock issued to benefit plans, net			2,723			4,161		6,884
Treasury stock issued to benefit plans, net (in shares)	110,357
Treasury stock purchased						(286)	286	0
Treasury stock purchased (in shares)	(4,576)
Balance at Dec. 31, 2019		51,975	927,337	882,851	(10,226)	(6,823)	10,120	1,855,234
Balance (in shares) at Dec. 31, 2019	51,793,923
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income				164,676				164,676
Other comprehensive income (loss), net of tax					72,303			72,303
Cumulative effect of change in accounting principle - ASC 326				1,140				1,140
Cash dividends declared:
Common				(88,484)				(88,484)
Common stock activity under employee stock ownership plans		417	15,375					15,792
Common stock activity under employee stock ownership plans (in shares)	416,614
Stock-based compensation			6,419					6,419
Stock issued for acquisition		1,363	75,579					76,942
Stock issued for acquisition (in shares)	1,363,259
Distribution of stock under deferred compensation arrangements			415			849	(1,264)	0
Distribution of stock under deferred compensation arrangements (in shares)	22,497
Treasury stock issued to benefit plans, net			38			47		85
Treasury stock issued to benefit plans, net (in shares)	1,240
Treasury stock purchased						(271)	271	0
Treasury stock purchased (in shares)	(4,406)
Balance at Dec. 31, 2020		53,755	1,025,163	960,183	62,077	(6,198)	9,127	2,104,107
Balance (in shares) at Dec. 31, 2020	53,593,127
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income				189,694				189,694
Other comprehensive income (loss), net of tax					(112,704)			(112,704)
Cash dividends declared:
Common				(91,591)				(91,591)
Common stock activity under employee stock ownership plans		337	9,484					9,821
Common stock activity under employee stock ownership plans (in shares)	337,822
Stock-based compensation			6,334					6,334
Distribution of stock under deferred compensation arrangements			323			694	(1,017)	0
Distribution of stock under deferred compensation arrangements (in shares)	18,089
Treasury stock purchased						(5,106)	252	(4,854)
Treasury stock purchased (in shares)	(70,991)
Balance at Dec. 31, 2021		$ 54,092	$ 1,041,304	$ 1,058,286	$ (50,627)	$ (10,610)	$ 8,362	$ 2,100,807
Balance (in shares) at Dec. 31, 2021	53,878,047

CONSOLIDATED STATEMENTS OF CH_2

CONSOLIDATED STATEMENTS OF CHANGES IN SHAREHOLDERS' EQUITY (Parenthetical) - $ / shares	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Cash dividends declared:
Dividends declared per common share (in dollars per share)	$ 1.70	$ 1.66	$ 1.58

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Operating activities:
Net income	$ 189,694	$ 164,676	$ 169,063
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	15,592	15,963	15,891
Amortization of intangible assets	14,051	14,297	15,956
Net accretion on securities, loans and borrowings	(22,501)	(11,353)	(6,176)
Stock-based compensation	6,334	6,419	5,285
Provision for credit losses	(8,839)	14,212	8,430
Provision (benefit) for deferred income taxes	7,989	(2,336)	(2,302)
Amortization of mortgage servicing rights	519	379	378
Unrealized (gain) loss on equity securities	(17)	6	(19)
Gain on debt extinguishment	0	(421)	0
Income from bank-owned life insurance policies	(2,012)	(1,915)	(1,678)
Gain on sales of investment securities, net	0	0	(4,882)
Net (gain) loss on sale of loans and other assets	(328)	(3,505)	11
Change in other assets and liabilities	2,064	(16,939)	2,545
Net cash provided by operating activities	202,546	179,483	202,502
Investing activities:
Proceeds from sales of available-for-sale investment securities	0	0	590,179
Proceeds from maturities, calls and paydowns of available-for-sale investment securities	423,738	885,549	209,857
Proceeds from maturities and redemptions of equity and other securities	2,946	516	3,995
Purchases of available-for-sale investment securities	(1,963,884)	(1,114,914)	(810,122)
Purchases of equity and other securities	(353)	(3,234)	(202)
Net decrease (increase) in loans	49,929	(185,131)	(140,382)
Cash (paid) received for acquisition, net of cash acquired of $541, $55,973, and $90,381, respectively	(29,329)	34,360	(4,653)
Settlement of bank owned life insurance policies	0	0	1,597
Purchases of premises and equipment, net	(13,176)	(14,395)	(5,686)
Real estate limited partnership investments	(646)	(1,471)	(1,637)
Net cash used in investing activities	(1,530,775)	(398,720)	(157,054)
Financing activities:
Net increase in deposits	1,686,194	1,713,733	104,435
Net increase/(decrease) in borrowings, net of payments of $4,769, $3,092, and $646, respectively	35,942	30,908	(64,405)
Payments on subordinated debt held by unconsolidated subsidiary trusts	(77,320)	(2,062)	(22,681)
Payments on subordinated notes payable	0	(10,000)	0
Issuance of common stock	9,821	15,792	6,915
Purchase of treasury stock	(5,106)	(271)	(286)
Sale of treasury stock	0	85	6,884
Increase in deferred compensation agreements	252	271	286
Cash dividends paid	(91,051)	(87,131)	(80,241)
Withholding taxes paid on share-based compensation	(1,244)	(1,313)	(3,159)
Net cash provided by (used in) financing activities	1,557,488	1,660,012	(52,252)
Change in cash and cash equivalents	229,259	1,440,775	(6,804)
Cash and cash equivalents at beginning of year	1,645,805	205,030	211,834
Cash and cash equivalents at end of year	1,875,064	1,645,805	205,030
Supplemental disclosures of cash flow information:
Cash paid for interest	13,752	21,169	25,425
Cash paid for income taxes	41,531	39,578	46,457
Supplemental disclosures of noncash financing and investing activities:
Dividends declared and unpaid	23,235	22,695	21,342
Transfers from loans to other real estate	520	1,291	2,522
Acquisitions:
Common stock issued	0	76,942	0
Fair value of assets acquired, excluding acquired cash and intangibles	1,339	547,654	548,856
Fair value of liabilities assumed	$ 1,101	$ 529,177	$ 589,396

CONSOLIDATED STATEMENTS OF CA_2

CONSOLIDATED STATEMENTS OF CASH FLOWS (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Investing activities:
Cash acquired related to acquisition	$ 541	$ 55,973	$ 90,381
Financing activities:
Payment made on borrowings	$ 4,769	$ 3,092	$ 646

SUMMARY OF SIGNIFICANT ACCOUNTI

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	12 Months Ended
	Dec. 31, 2021
ACCOUNTING POLICIES
ACCOUNTING POLICIES	NOTE A: SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Nature of Operations Community Bank System, Inc. (the “Company”) is a registered financial holding company which wholly-owns two significant consolidated subsidiaries: Community Bank, N.A. (the “Bank” or “CBNA”), and Benefit Plans Administrative Services, Inc. (“BPAS”). As of December 31, 2021, BPAS owns five subsidiaries: Benefit Plans Administrative Services, LLC (“BPA”), a provider of defined benefit contribution plan administration services; Northeast Retirement Services, LLC (“NRS”), a provider of institutional transfer agency, master recordkeeping services, fund administration, trust and retirement plan services; BPAS Actuarial & Pension Services, LLC (“BPAS-APS”), a provider of actuarial and benefit consulting services; BPAS Trust Company of Puerto Rico, a Puerto Rican trust company; and Hand Benefits & Trust Company (“HB&T”), a provider of collective investment fund administration and institutional trust services. BPA owns one subsidiary, Fringe Benefits Design of Minnesota, Inc. ("FBD"), a provider of retirement plan administration and benefit consulting services. NRS owns one subsidiary, Global Trust Company, Inc. (“GTC”), a non-depository trust company which provides fiduciary services for collective investment trusts and other products. HB&T owns one subsidiary, Hand Securities Inc. (“HSI”), an introducing broker-dealer. As of December 31, 2021, the Bank operated 206 full-service branches and 12 drive-thru only locations operating as Community Bank, N.A. throughout 42 counties of Upstate New York, six counties of Northeastern Pennsylvania, 12 counties of Vermont and one county of Western Massachusetts, offering a range of commercial and retail banking services. The Bank owns the following operating subsidiaries: The Carta Group, Inc. (“Carta Group”), CBNA Preferred Funding Corporation (“PFC”), CBNA Treasury Management Corporation (“TMC”), Community Investment Services, Inc. (“CISI”), Nottingham Advisors, Inc. (“Nottingham”), OneGroup NY, Inc. (“OneGroup”), OneGroup Wealth Partners, Inc. ("Wealth Partners") and Oneida Preferred Funding II LLC (“OPFC II”). OneGroup is a full-service insurance agency offering personal and commercial lines of insurance and other risk management products and services. PFC and OPFC II primarily act as investors in residential and commercial real estate activities. TMC provides cash management, investment, and treasury services to the Bank. CISI, Carta Group and Wealth Partners provide broker-dealer and investment advisory services. Nottingham provides asset management services to individuals, corporations, corporate pension and profit sharing plans, and foundations. Principles of Consolidation The consolidated financial statements include the accounts of the Company and its subsidiaries. All intercompany accounts and transactions have been eliminated in consolidation. Variable Interest Entities (“VIE”) are legal entities in which equity investors do not have the characteristics of a controlling financial interest or do not have sufficient equity at risk for the legal entities to finance its activities without additional subordinated financial support. VIEs may be required to be consolidated by a company if it is determined the company is the primary beneficiary of a VIE. The primary beneficiary of a VIE is the enterprise that has: (1) the power to direct the activities of the VIE that most significantly impact the VIE’s economic performance, and (2) the obligation to absorb losses of the VIE that could potentially be significant to the VIE or the right to receive benefits of the VIE that could potentially be significant to the VIE. The Company’s VIE’s are described in more detail in Note T to the consolidated financial statements. Critical Accounting Estimates in the Preparation of Financial Statements The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. Critical accounting estimates include the allowance for credit losses, actuarial assumptions associated with the pension, post-retirement and other employee benefit plans, the provision for income taxes, investment valuation, the carrying value of goodwill and other intangible assets, the fair value of contingent consideration liabilities, and acquired loan valuations. Risk and Uncertainties In the normal course of its business, the Company encounters economic and regulatory risks. There are three main components of economic risk: interest rate risk, credit risk and market risk. The Company is subject to interest rate risk to the degree that its interest-bearing liabilities mature or reprice at different speeds, or on a different basis, from its interest-earning assets. The Company’s primary credit risk is the risk of default on the Company’s loan portfolio that results from the borrowers’ inability or unwillingness to make contractually required payments. Market risk reflects potential changes in the value of collateral underlying loans, the fair value of investment securities, and loans held for sale. The Company is subject to regulations of various governmental agencies. These regulations can change significantly from period to period. The Company also undergoes periodic examinations by the regulatory agencies which may subject it to further changes with respect to asset valuations, amounts of required credit loss allowances, and operating restrictions resulting from the regulators’ judgments based on information available to them at the time of their examinations. The extent to which the ongoing coronavirus pandemic ("COVID-19") impacts the Company's business and financial results depends on numerous evolving factors including, but not limited to: the magnitude and duration of COVID-19, the extent to which it continues to impact national and international macroeconomic conditions including interest rates, unemployment rates, the trajectory of the ongoing economic recovery, and governmental and business reactions to the pandemic. The Company assessed certain accounting matters that generally require consideration of forecasted financial information in context with the information reasonably available to the Company and the unknown future impacts of COVID-19 as of December 31, 2021 and through the date of this Annual Report on Form 10-K. The accounting matters assessed included, but were not limited to, the Company's allowance for credit losses, changes in fee and interest income, and the carrying value of goodwill and other long-lived assets. Revenue Recognition The Company recognizes revenue in accordance with 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. 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. 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 December 31, 2021, $31.6 million of accounts receivable, including $9.1 million of unbilled fee revenue, and $2.2 million of unearned revenue was recorded in the consolidated statements of condition. As of December 31, 2020, $30.3 million of accounts receivable, including $7.7 million of unbilled fee revenue, and $1.4 million of unearned revenue was recorded in the consolidated statements of condition. Contract Acquisition Costs Under the guidance 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. Cash and Cash Equivalents For purposes of reporting cash flows, cash and cash equivalents include cash on hand, amounts due from banks, and highly liquid investments with original maturities of less than 90 days. The carrying amounts reported in the consolidated statements of condition for cash and cash equivalents approximate those assets’ fair values. As of December 31, 2021 and 2020, cash and cash equivalents reported in the consolidated statements of condition included cash due from banks of $11.0 million and $7.7 million, respectively. Cash due from banks may at times exceed federally insured limits. 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. The Company did not use the held-to-maturity classification in 2021 or 2020. 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. None of the Company’s investment securities have been classified as trading securities at December 31, 2021 or 2020. Interest income includes amortization of purchase premiums or discounts. Premiums and discounts on securities are amortized on the level-yield method without anticipating prepayments, except for mortgage-backed securities where prepayments are anticipated. Gains and losses are recorded on the trade date and determined using the specific identification method. 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. Certain equity securities that do not have a readily determinable fair value are stated at cost, 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”) and 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. 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. Allowance for Credit Losses – Debt Securities For held-to-maturity debt securities, the Company measures expected credit losses on a collective basis by major security type. The estimates of expected credit losses considers historical credit loss information that is adjusted for current conditions and reasonable and supportable forecasts. Accrued interest receivable on held-to-maturity securities is excluded from the estimate of credit losses. For available-for-sale debt securities in an unrealized loss position, the Company first assesses whether it intends to sell, or it more likely than not that it will be required to sell the security before recovery of its amortized cost basis. If either of the criteria regarding intent or requirement to sell is met, the security’s amortized cost basis is written down to fair value through income. For available-for-sale debt securities that do not meet the aforementioned criteria, the Company evaluates whether the decline in fair value has resulted from credit losses or other factors. In making this assessment, management considers the security structure, recent security collateral performance metrics, if applicable, external credit ratings, failure of the issuer to make scheduled interest or principal payments, judgment about and expectations of future performance, and relevant independent industry research, analysis, and forecasts. This assessment involves a high degree of subjectivity and judgment that is based on the information available to management at a point in time. If this assessment indicates that a credit loss exists, the present value of the cash flows expected to be collected from the security are compared to the amortized cost basis of the security. If the present value of the cash flows expected to be collected from the security is less than the amortized cost basis of the security, a credit loss exists and an allowance for credit losses is recorded, limited by the amount that the fair value is less than the amortized cost basis. Any impairment that has not been recorded through an allowance for credit losses is recognized in other comprehensive income. Changes in the allowance for credit losses are recorded as provision for (or reversal of) credit losses in the consolidated statements of income. Losses are charged against the allowance when management believes the uncollectibility of an available-for-sale security is confirmed or when either of the criteria regarding intent or requirement to sell is met. Accrued interest receivable on available-for-sale debt securities, included in accrued interest and fees receivable on the consolidated statements of condition, totaled $15.8 million and $13.3 million at December 31, 2021 and 2020, respectively, and is excluded from the estimate of credit losses. Prior to the adoption of ASU No. 2016-13, Financial Instruments – Credit Losses (Topic 326) Loans Loans that management has the intent and ability to hold for the foreseeable future or until maturity or payoff are reported at amortized cost, net of allowance for credit losses. Amortized cost is the principal balance outstanding, net of purchase premiums and discounts, and deferred loan fees and costs. Mortgage loans held for sale are carried at fair value and are included in loans held for sale on the consolidated statements of condition. 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. The carrying amount of accrued interest approximates its fair value. Interest on loans is accrued and credited to operations based upon the principal amount outstanding. Nonrefundable loan fees and related direct costs are deferred and included in the loan balances where they are amortized over the life of the loan as an adjustment to loan yield using the effective yield method. Premiums and discounts on purchased loans are amortized using the effective yield method over the life of the loans. Accrued interest receivable on loans is included in accrued interest and fees receivable on the consolidated statements of condition and is excluded from the estimate of credit losses and amortized cost basis of loans. An allowance for credit losses is not measured for accrued interest receivable on loans as the Company writes off the uncollectible accrued interest balance in a timely manner upon recognition of credit deterioration of the underlying loan. The Company places a loan on nonaccrual status when the loan becomes 90 days past due (or sooner, if management concludes collection is doubtful), except when, in the opinion of management, it is well-collateralized and in the process of collection. A loan may be placed on nonaccrual status earlier than 90 days past due if there is deterioration in the financial position of the borrower or if other conditions of the loan so warrant. When a loan is placed on nonaccrual status, uncollected accrued interest is reversed against interest income and the amortization of nonrefundable loan fees and related direct costs is discontinued. Interest income during the period the loan is on nonaccrual status is recorded on a cash basis after recovery of principal is reasonably assured. Nonaccrual loans are returned to accrual status when management determines that the borrower’s performance has improved and that both principal and interest are collectible. This generally requires a sustained period of timely principal and interest payments and a well-documented credit evaluation of the borrower’s financial condition. ​ The Company’s charge-off policy by loan type is as follows: ● Business lending loans are generally charged-off to the extent outstanding principal exceeds the fair value of estimated proceeds from collection efforts, including liquidation of collateral. The charge-off is recognized when the loss becomes reasonably quantifiable. ● Consumer installment loans are generally charged-off to the extent outstanding principal exceeds the fair value of collateral, and are recognized by the end of the month in which the loan becomes 90 days past due. ● Consumer mortgage and home equity loans are generally charged-off to the extent outstanding principal exceeds the fair value of the property, less estimated costs to sell, and are recognized when the loan becomes 180 days past due. ​ Allowance for Credit Losses – Loans The allowance for credit losses is a valuation account that is netted against the loans’ amortized cost basis to present the net amount expected to be collected on the loans. Loans are charged off against the allowance when management believes the uncollectibility of a loan balance is confirmed. Management estimates the allowance balance using relevant available information from internal and external sources relating to past events, current conditions, and reasonable and supportable forecasts. Historical credit loss experience provides the basis for the estimation of expected credit losses. Adjustments are made for differences in current loan-specific risk characteristics such as differences in underwriting standards, portfolio mix, acquired loans, delinquency level, risk ratings or term of loans as well as changes in macroeconomic conditions, such as changes in unemployment rates, property values such as home prices, commercial real estate prices and automobile prices, gross domestic product, recession probability, and other relevant factors. The segments of the Company's loan portfolio are disaggregated into the following classes that allow management to monitor risk and performance: ● Business lending is comprised of general purpose commercial and industrial loans including, but not limited to, agricultural-related and dealer floor plans, loans to not-for-profit enterprises, as well as mortgages on commercial property and Paycheck Protection Program ("PPP") loans. The portfolio segment is further broken into portfolio classes based on risks associated with the collateral supporting the loans. Each class of business lending can also have different payment structures. Business lending loans are generally higher dollar loans and a large portion are risk rated at least annually. ● Consumer mortgages consist primarily of fixed rate residential instruments, typically 10 - 30 years in contractual term, secured by first liens on real property. FICO scores are used to monitor higher risks related to this type of lending with FICO AB referring to higher tiered loans with FICO scores greater than or equal to 720 as compared to FICO CDE with lower FICO scores less than 720 and potentially higher risk. ● Consumer indirect consists primarily of installment loans originated through selected dealerships and are generally secured by automobiles, marine and other recreational vehicles. Collateral securing the loans was used to further disaggregate this portfolio as charge-offs can vary depending on the purpose of the loan. Non-auto loans often have longer terms, and generally have higher risk due to declines in collateral value given the nature of the property. ● Consumer direct consists of all other loans to consumers such as personal installment loans and check credit lines of credit. ● Home equity products are 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 allowance for credit losses is measured on a collective (pool) basis when similar risk characteristics exist, including collateral type, credit ratings/scores, size, duration, interest rate structure, industry, geography, origination vintage, and payment structure. The Company has identified the following portfolio segments and classes and measures the allowance for credit losses using the following methods: ​ ​ ​ ​ ​ ​ Loan Portfolio Segment Loan Portfolio Class Allowance for Credit Losses Methodology Business lending Commercial real estate multi family Cumulative loss rate Business lending Commercial real estate non-owner occupied Cumulative loss rate Business lending Commercial real estate owner occupied Cumulative loss rate Business lending Commercial and industrial loans Vintage loss rate Business lending Commercial and industrial lines of credit Line loss Business lending Municipal Cumulative loss rate Business lending Other business Cumulative loss rate Business lending Paycheck Protection Program Cumulative loss rate Consumer mortgage Consumer mortgage FICO AB Cumulative loss rate Consumer mortgage Consumer mortgage FICO CDE Cumulative loss rate Consumer indirect Indirect new auto Vintage loss rate Consumer indirect Indirect used auto Vintage loss rate Consumer indirect Indirect non-auto Vintage loss rate Consumer direct Consumer check credit Line loss Consumer direct Consumer direct Vintage loss rate Home equity Home equity fixed rate Vintage loss rate Home equity Home equity lines of credit Line loss ​ The cumulative loss rate method uses historical loss data applied against multiple pools of loans and uses a quantitatively based management overlay in order to capture the risk for a loan's entire expected life. These loss rates are then applied to current balances to achieve a required reserve before qualitative adjustments. The line loss method calculates the quantitative required reserve for lines of credit. This method contains several different underlying calculations including average annual loss rate, pay-down rate, cumulative loss, average draw percentage, and undrawn liability reserve. The vintage loss rate method calculates annual loss rates by origination year. The results of this model are then applied to outstanding balances, which correspond to the origination period for each annual loss rate. In addition to the risk characteristics noted above, management considers the portion of acquired loans to the overall segment balance, as well as current delinquency and charge-off trends compared to historical time periods. Loans that do not share risk characteristics are evaluated on an individual basis. Loans that are individually assessed are not included in the collective evaluation. When management determines that foreclosure is probable or when the borrower is experiencing financial difficulty at the reporting date and repayment is expected to be provided substantially through the operation or sale of the collateral, expected credit losses are based on the fair value of the collateral at the reporting date, adjusted for selling costs as appropriate. Expected credit losses are estimated over the contractual term of the loans and adjusted for expected prepayments when appropriate. The contractual term excludes expected extensions, renewals, and modifications unless management has a reasonable expectation at the reporting date that a troubled debt restructuring will be executed with an individual borrower or the extension or renewal options are included in the original or modified contract at the reporting date and are not unconditionally cancellable by the Company. Certain business lending, consumer direct, and home equity loans do not have stated maturities. In determining the estimated life of these loans, management first estimates the future cash flows expected to be received and then applies those expected future cash flows to the balance. Expected credit losses for lines of credit with no stated maturity are determined by estimating the amount and timing of all principal payments expected to be received after the reporting period and allocating those principal payments between the balance outstanding as of the reporting period and the balance of future receivables expected to be originated through subsequent usage of the unconditionally cancellable loan commitment associated with the account until the expected payments have been fully allocated. An additional allowance for credit loss is recorded for the excess of the balance outstanding as of the reporting period over the expected principal payments allocated to that balance. Prior to the adoption of ASU No. 2016-13, Financial Instruments – Credit Losses (Topic 326) Troubled Debt Restructuring A loan for which the terms have been modified resulting in a concession, and for which the borrower is experiencing financial difficulties, is considered to be a troubled debt restructuring ("TDR"). The allowance for credit loss on a TDR is measured using the same method as all other loans, except when the value of a concession cannot be measured using a method other than the discounted cash flow method. When the value of a concession is measured using the discounted ca

ACQUISITIONS

ACQUISITIONS	12 Months Ended
	Dec. 31, 2021
ACQUISITIONS
ACQUISITIONS	NOTE B: ACQUISITIONS Pending Acquisition On October 4, 2021, the Company announced that the Bank had entered into an agreement to acquire Elmira Savings Bank (“Elmira”), a twelve branch banking franchise headquartered in Elmira, New York, for $82.8 million in cash. The acquisition will enhance the Company’s presence in five counties in New York’s Southern Tier and Finger Lakes regions. The merger was approved by the shareholders of Elmira on December 14, 2021. The Company expects to complete the acquisition in the second quarter of 2022, subject to customary closing conditions, including required regulatory approval. The Company expects to incur certain one-time, transaction-related costs in connection with the Elmira acquisition. Current and Prior Period Acquisitions On August 2, 2021, the Company, through its subsidiary OneGroup NY, Inc. (“OneGroup”), completed its acquisition of certain assets and liabilities of the Thomas Gregory Associates Insurance Brokers, Inc. (“TGA”), a specialty-lines insurance broker based in the Boston, Massachusetts area, for $11.6 million in cash plus contingent consideration with a fair value at acquisition date of $1.5 million. The Company recorded a $10.9 million customer list intangible asset and $2.2 million of goodwill in conjunction with the acquisition. The effects of the acquired assets and liabilities have been included in the consolidated financial statements since that date. Revenues of approximately $0.6 million and direct expenses of approximately $0.6 million from TGA were included in the consolidated income statement for the year ended December 31, 2021. The acquisition of TGA includes a contingent consideration arrangement that requires additional consideration to be paid by the Company based on the future retained revenue of TGA over a three-year period. Amounts are payable in two payments, the first of which is two years after the acquisition date, and the second three years after the acquisition date. The range of the undiscounted amounts the Company could pay under the contingent consideration agreement is between zero and $3.4 million. The fair value of the contingent consideration recognized on the acquisition date of $1.5 million was estimated by applying the income approach; a measure that is based on significant Level 3 inputs not readily observable in the market. Key assumptions at the date of acquisition include (1) a discount rate range of 0.82% to 1.09%, and (2) probability adjusted level of retained revenue between $2.3 million and $3.8 million. The contingent consideration related to the TGA acquisition was revalued at December 31, 2021. The range of the undiscounted amounts the Company could pay under the agreement remained at between zero and $3.4 million. Key assumptions include (1) a discount rate range of 1.38% to 1.65%, and (2) probability adjusted level of retained revenue between $3.0 million and $3.4 million. Based on the results of the revaluation, no adjustments were made to the fair value of the contingent consideration related to the TGA acquisition at December 31, 2021. On July 1, 2021, the Company, through its subsidiary BPA, completed its acquisition of Fringe Benefits Design of Minnesota, Inc. (“FBD”) for $15.4 million in cash plus contingent consideration with a fair value at acquisition date of $1.4 million. The Company recorded a $14.0 million customer list intangible asset and $2.0 million of goodwill in conjunction with the acquisition. The effects of the acquired assets have been included in the consolidated financial statements since that date. Revenues of approximately $2.8 million and direct expenses of approximately $2.5 million from FBD were included in the consolidated income statement for the year ended December 31, 2021. The acquisition of FBD includes a contingent consideration arrangement that requires additional consideration to be paid by the Company based on the future retained revenue of FBD over a two-year period. Amounts are payable three years after the acquisition date. The range of the undiscounted amounts the Company could pay under the contingent consideration agreement is between zero and $2.7 million. The fair value of the contingent consideration recognized on the acquisition date of $1.4 million was estimated by applying the income approach; a measure that is based on significant Level 3 inputs not readily observable in the market. Key assumptions at the date of acquisition include (1) a discount rate of 1.05%, and (2) probability adjusted level of retained revenue between $5.6 million and $5.8 million. The contingent consideration related to the FBD acquisition was revalued at December 31, 2021. The range of the undiscounted amounts the Company could pay under the agreement remained at between zero and $2.7 million. Key assumptions include (1) a discount rate of 1.50%, and (2) probability adjusted level of retained revenue between $5.6 million and $5.8 million. Based on the results of the revaluation, the Company recorded a $0.2 million acquisition-related contingent consideration adjustment in the consolidated statements of income related to the FBD acquisition, resulting in an adjusted fair value of $1.6 million at December 31, 2021. On June 1, 2021, the Company, through its subsidiary OneGroup, completed its acquisition of certain assets and liabilities of NuVantage Insurance Corp. (“NuVantage”), an insurance agency headquartered in Melbourne, Florida. The Company paid $2.9 million in cash and recorded a $1.4 million customer list intangible asset and $1.4 million of goodwill in conjunction with the acquisition. The effects of the acquired assets and liabilities have been included in the consolidated financial statements since that date. Revenues of approximately $0.7 million and direct expenses of approximately $0.6 million from NuVantage were included in the consolidated income statement for the year ended December 31, 2021. On June 12, 2020, the Company completed its merger with Steuben Trust Corporation (“Steuben”), parent company of Steuben Trust Company, a New York State chartered bank headquartered in Hornell, New York, for $98.6 million in Company stock and cash, comprised of $21.6 million in cash and the issuance of 1.36 million shares of common stock. The merger extended the Company’s footprint into two new counties in Western New York State, and enhanced the Company’s presence in four Western New York State counties in which it currently operates. In connection with the merger, the Company added 11 full-service offices to its branch service network and acquired $607.8 million of assets, including $339.7 million of loans and $180.5 million of investment securities, as well as $516.3 million of deposits. Goodwill of $20.0 million was recognized as a result of the merger. The effects of the acquired assets and liabilities have been included in the consolidated financial statements since that date. Revenues, excluding interest income on acquired investments, interest income on acquired consumer indirect loans, and revenues associated with acquired loans and deposits consolidated into the legacy branch network, of approximately $13.1 million and $7.7 million, and direct expenses, which may not include certain shared expenses, of approximately $5.1 million and $2.6 million from Steuben were included in the consolidated income statement for the years ended December 31, 2021 and 2020, respectively. The Company incurred certain one-time, transaction-related costs in connection with the Steuben acquisition. On September 18, 2019, the Company, through its subsidiary, CISI, completed its acquisition of certain assets of a practice engaged in the financial services business headquartered in Syracuse, New York. The Company paid $0.5 million in cash to acquire a customer list, and recorded a $0.5 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 July 12, 2019, the Company completed its merger with Kinderhook Bank Corp. (“Kinderhook”), parent company of The National Union Bank of Kinderhook, headquartered in Kinderhook, New York, for $93.4 million in cash. The merger added 11 branch locations across a five county area in the Capital District of Upstate New York. The merger resulted in the acquisition of $642.8 million of assets, including $479.9 million of loans and $39.8 million of investment securities, as well as $568.2 million of deposits and $40.0 million in goodwill. The effects of the acquired assets and liabilities have been included in the consolidated financial statements since that date. Revenues, excluding interest income on acquired investments, of approximately $11.8 million, $16.3 million, and $10.6 million and direct expenses, which may not include certain shared expenses, of approximately $7.1 million, $7.4 million, and $4.7 million from Kinderhook were included in the consolidated income statements for the years ended December 31, 2021, 2020, and 2019, respectively. On January 2, 2019, the Company, through its subsidiary, CISI, completed its acquisition of certain assets of Wealth Resources Network, Inc. (“Wealth Resources”), a financial services business headquartered in Liverpool, New York. The Company paid $1.2 million in cash to acquire a customer list from Wealth Resources, 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. 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 acquisitions, and were subject to adjustment based on updated information not available at the time of the acquisitions. During 2021, the carrying amount of other liabilities associated with the Steuben acquisition decreased by $0.3 million as a result of an adjustment to accrued income taxes and deferred income taxes. Goodwill associated with the Steuben acquisition decreased $0.3 million as a result of this adjustment. The carrying amount of other assets associated with the FBD acquisition increased by $0.02 million as a result of an adjustment to other assets. Goodwill associated with the FBD acquisition decreased by $0.02 million as a result of this adjustment. The above referenced acquisitions generally expanded the Company’s geographical presence in New York, Florida, Massachusetts, and Minnesota, 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: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2021 ​ ​ 2020 ​ 2019 (000s omitted) TGA ​ FBD NuVantage Total ​ ​ Steuben Total (1) Consideration: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Cash $ 11,620 ​ $ 15,350 ​ $ 2,900 ​ $ 29,870 ​ $ 21,613 ​ $ 95,034 Community Bank System, Inc. common stock ​ 0 ​ 0 ​ 0 ​ 0 ​ ​ 76,942 ​ 0 Contingent consideration ​ 1,500 ​ ​ 1,400 ​ ​ 0 ​ ​ 2,900 ​ ​ 0 ​ ​ 0 Total net consideration ​ 13,120 ​ 16,750 ​ 2,900 ​ 32,770 ​ ​ 98,555 ​ 95,034 Recognized amounts of identifiable assets acquired and liabilities assumed: ​ ​ ​ ​ ​ ​ ​ ​ ​ Cash and cash equivalents ​ 0 ​ 541 ​ 0 ​ 541 ​ ​ 55,973 ​ 90,381 Investment securities ​ 0 ​ 0 ​ 0 ​ 0 ​ ​ 180,497 ​ 39,770 Loans, net of allowance for credit losses on PCD loans (2) ​ 0 ​ 0 ​ 0 ​ 0 ​ ​ 339,017 ​ 479,877 Premises and equipment, net ​ 279 ​ 282 ​ 199 ​ 760 ​ ​ 7,764 ​ 13,970 Accrued interest and fees receivable ​ 0 ​ 0 ​ 0 ​ 0 ​ ​ 2,701 ​ 1,130 Other assets ​ 0 ​ 579 ​ 0 ​ 579 ​ ​ 17,675 ​ 14,109 Core deposit intangibles ​ 0 ​ 0 ​ 0 ​ 0 ​ ​ 2,928 ​ 3,573 Other intangibles ​ 10,900 ​ 14,000 ​ 1,437 ​ 26,337 ​ ​ 1,196 ​ 1,650 Deposits ​ 0 ​ 0 ​ 0 ​ 0 ​ ​ (516,274) ​ (568,161) Other liabilities ​ (229) ​ (698) ​ (174) ​ (1,101) ​ ​ (4,841) ​ (2,922) Other Federal Home Loan Bank borrowings ​ 0 ​ 0 ​ 0 ​ 0 ​ ​ (6,000) ​ (2,420) Subordinated notes payable ​ 0 ​ 0 ​ 0 ​ 0 ​ ​ 0 ​ (13,831) Subordinated debt held by unconsolidated subsidiary trusts ​ 0 ​ 0 ​ 0 ​ 0 ​ ​ (2,062) ​ (2,062) Total identifiable assets, net ​ 10,950 ​ 14,704 ​ 1,462 ​ 27,116 ​ ​ 78,574 ​ 55,064 Goodwill $ 2,170 ​ $ 2,046 ​ $ 1,438 ​ $ 5,654 ​ $ 19,981 ​ $ 39,970 ​ (1) Includes amounts related to the Kinderhook and both CISI acquisitions completed in 2019. (2) Acquisition-related allowance for credit losses on purchased credit deteriorated ("PCD") loans applicable beginning in 2020. Under ASC 310-30, 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 credit 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. On January 1, 2020, the Company adopted ASU No. 2016-13, Financial Instruments - Credit Losses (Topic 326) The Company has acquired loans from Steuben for which there was evidence of a more-than-insignificant deterioration in credit quality since origination. There were no investment securities acquired from Steuben for which there was evidence of a more-than-insignificant deterioration in credit quality since origination. The carrying amount of those loans is as follows at the date of acquisition: ​ ​ ​ ​ ​ (000s omitted) PCD Loans Par value of PCD loans at acquisition ​ $ 35,906 Allowance for credit losses at acquisition ​ (668) Non-credit premium at acquisition ​ 103 Fair value of PCD loans at acquisition ​ $ 35,341 ​ The following is a summary of the remaining loans acquired from Steuben for which there was no evidence of a more-than-insignificant deterioration in credit quality since origination at the date of acquisition: ​ ​ ​ ​ ​ (000s omitted) Non-PCD Loans Contractually required principal and interest at acquisition ​ $ 400,738 Contractual cash flows not expected to be collected ​ (2,994) Expected cash flows at acquisition ​ 397,744 Interest component of expected cash flows ​ (94,068) Fair value of non-PCD loans at acquisition ​ $ 303,676 ​ The following is a summary of the loans acquired from Kinderhook at the date of acquisition: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Acquired ​ Acquired ​ Total ​ ​ Impaired ​ Non-impaired ​ Acquired (000s omitted) Loans Loans Loans Contractually required principal and interest at acquisition ​ $ 13,350 ​ $ 636,384 ​ $ 649,734 Contractual cash flows not expected to be collected ​ (4,176) ​ (5,472) ​ (9,648) Expected cash flows at acquisition ​ 9,174 ​ 630,912 ​ 640,086 Interest component of expected cash flows ​ (551) ​ (159,658) ​ (160,209) Fair value of acquired loans ​ $ 8,623 ​ $ 471,254 ​ $ 479,877 ​ The fair value of the Company’s common stock issued for the Steuben acquisition was determined using the market close price of the stock on June 12, 2020. ​ 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 fair value of subordinated notes payable was estimated using discounted cash flows and interest rates being offered on similar securities. Subordinated notes payable assumed with the Kinderhook acquisition included $3.0 million of subordinated notes with a fixed interest rate of 6.0% maturing in February 2028 November 2025 The core deposit intangibles and other intangibles related to the NuVantage acquisition, Steuben acquisition, both acquisitions completed by CISI in 2019, and the Kinderhook acquisition are being amortized using an accelerated method over their estimated usefu , respectively. The goodwill, which is not amortized for book purposes, was assigned to the Banking segment for the Steuben and Kinderhook acquisitions, the All Other segment for the NuVantage and TGA acquisitions, and the Employee Benefit Services segment for the FBD acquisition. Goodwill arising from the FBD, Steuben, and Kinderhook acquisitions is not deductible for tax purposes. Goodwill arising from the NuVantage and TGA acquisitions is deductible for tax purposes. Direct costs related to the acquisitions were expensed as incurred. Merger and acquisition integration-related expenses amount to $0.7 million, $4.9 million and $8.6 million during 2021, 2020 and 2019, respectively, and have been separately stated in the consolidated statements of income. Supplemental Pro Forma Financial Information (Unaudited) The following unaudited condensed pro forma information assumes the Steuben acquisition had been completed as of January 1, 2019 for the years ended December 31, 2020 and 2019 and the Kinderhook acquisitions had been completed as of January 1, 2018 for the year ended December 31, 2019. The pro forma information does not include amounts related to the NuVantage, FBD, or TGA acquisitions completed in 2021, or the two acquisitions completed by CISI in 2019, as the amounts were immaterial. The table below has been prepared for comparative purposes only and is not necessarily indicative of the actual results that would have been attained had the acquisitions occurred as of the beginning of the year presented, nor is it indicative of the Company’s future results. Furthermore, the unaudited pro forma information does not reflect management’s estimate of any revenue-enhancing opportunities nor anticipated cost savings that may have occurred as a result of the integration and consolidation of the acquisitions. The pro forma information set forth below reflects the historical results of Steuben and Kinderhook combined with the Company’s consolidated statements of income with adjustments related to (a) certain purchase accounting fair value adjustments and (b) amortization of customer lists and core deposit intangibles. Acquisition expenses related to the Steuben transaction totaling $4.8 million for the year ended December 31, 2020 were included in the pro forma information as if they were incurred in 2019. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Pro Forma (Unaudited) ​ ​ Year Ended December 31, (000s omitted) 2020 2019 Total revenue, net of interest expense ​ $ 607,382 ​ $ 626,229 Net income ​ 171,147 ​ 180,237 ​

INVESTMENT SECURITIES

INVESTMENT SECURITIES	12 Months Ended
	Dec. 31, 2021
INVESTMENT SECURITIES.
INVESTMENT SECURITIES	NOTE C: INVESTMENT SECURITIES The amortized cost and estimated fair value of investment securities as of December 31 are as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2021 2020 ​ ​ ​ ​ ​ Gross ​ Gross ​ ​ ​ ​ ​ ​ ​ Gross ​ Gross ​ ​ ​ ​ ​ Amortized ​ Unrealized ​ Unrealized ​ Estimated ​ Amortized ​ Unrealized ​ Unrealized ​ Estimated (000’s omitted) Cost Gains Losses Fair Value Cost Gains Losses Fair Value Available-for-Sale Portfolio: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ U.S. Treasury and agency securities ​ $ 4,064,624 ​ $ 39,997 ​ $ 106,057 ​ $ 3,998,564 ​ $ 2,423,236 ​ $ 94,741 ​ $ 16,595 ​ $ 2,501,382 Obligations of state and political subdivisions ​ ​ 413,019 ​ ​ 17,326 ​ ​ 56 ​ ​ 430,289 ​ ​ 451,028 ​ ​ 24,632 ​ ​ 0 ​ ​ 475,660 Government agency mortgage-backed securities ​ ​ 474,506 ​ ​ 7,615 ​ ​ 5,065 ​ ​ 477,056 ​ ​ 506,540 ​ ​ 16,280 ​ ​ 182 ​ ​ 522,638 Corporate debt securities ​ ​ 8,000 ​ ​ 39 ​ ​ 77 ​ ​ 7,962 ​ ​ 4,499 ​ ​ 137 ​ ​ 1 ​ ​ 4,635 Government agency collateralized mortgage obligations ​ ​ 19,953 ​ ​ 410 ​ ​ 24 ​ ​ 20,339 ​ ​ 42,476 ​ ​ 1,111 ​ ​ 10 ​ ​ 43,577 Total available-for-sale portfolio ​ $ 4,980,102 ​ $ 65,387 ​ $ 111,279 ​ $ 4,934,210 ​ $ 3,427,779 ​ $ 136,901 ​ $ 16,788 ​ $ 3,547,892 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Equity and other Securities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Equity securities, at fair value ​ $ 251 ​ $ 212 ​ $ 0 ​ $ 463 ​ $ 251 ​ $ 194 ​ $ 0 ​ $ 445 Federal Home Loan Bank common stock ​ 7,188 ​ 0 ​ 0 ​ 7,188 ​ 7,468 ​ 0 ​ 0 ​ 7,468 Federal Reserve Bank common stock ​ 33,916 ​ 0 ​ 0 ​ 33,916 ​ 33,916 ​ 0 ​ 0 ​ 33,916 Other equity securities, at adjusted cost ​ 2,562 ​ 750 ​ 0 ​ 3,312 ​ 4,876 ​ 750 ​ 0 ​ 5,626 Total equity and other securities ​ $ 43,917 ​ $ 962 ​ $ 0 ​ $ 44,879 ​ $ 46,511 ​ $ 944 ​ $ 0 ​ $ 47,455 ​ A summary of investment securities that have been in a continuous unrealized loss position for less than or greater than twelve months is as follows: As of December 31, 2021 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Less than 12 Months 12 Months or Longer Total ​ ​ ​ ​ ​ ​ ​ Gross ​ ​ ​ ​ ​ ​ Gross ​ ​ ​ ​ ​ ​ Gross ​ ​ ​ ​ ​ ​ Unrealized ​ ​ ​ ​ ​ Unrealized ​ ​ ​ ​ ​ Unrealized (000’s omitted) # Fair Value Losses # Fair Value Losses # Fair Value Losses Available-for-Sale Portfolio: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ U.S. Treasury and agency securities ​ 47 ​ $ 1,224,101 ​ $ 14,873 ​ 13 ​ $ 900,462 ​ $ 91,184 ​ 60 ​ $ 2,124,563 ​ $ 106,057 Obligations of state and political subdivisions ​ 27 ​ 23,966 ​ 56 ​ 0 ​ 0 ​ 0 ​ 27 ​ 23,966 ​ 56 Government agency mortgage-backed securities ​ 147 ​ 139,442 ​ 2,475 ​ 52 ​ 67,273 ​ 2,590 ​ 199 ​ 206,715 ​ 5,065 Corporate debt securities ​ 1 ​ ​ 4,923 ​ ​ 77 ​ 0 ​ ​ 0 ​ ​ 0 ​ 1 ​ ​ 4,923 ​ ​ 77 Government agency collateralized mortgage obligations ​ 18 ​ 3,146 ​ 24 ​ 1 ​ 53 ​ 0 ​ 19 ​ 3,199 ​ 24 Total available-for-sale investment portfolio ​ 240 ​ $ 1,395,578 ​ $ 17,505 ​ 66 ​ $ 967,788 ​ $ 93,774 ​ 306 ​ $ 2,363,366 ​ $ 111,279 ​ As of December 31, 2020 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Less than 12 Months 12 Months or Longer Total ​ ​ ​ ​ ​ ​ ​ Gross ​ ​ ​ ​ ​ ​ Gross ​ ​ ​ ​ ​ ​ Gross ​ ​ ​ ​ ​ ​ Unrealized ​ ​ ​ ​ ​ Unrealized ​ ​ ​ ​ ​ Unrealized (000’s omitted) # Fair Value Losses # Fair Value Losses # Fair Value Losses Available-for-Sale Portfolio: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ U.S. Treasury and agency securities ​ 13 ​ $ 831,015 ​ $ 16,595 ​ 0 ​ $ 0 ​ $ 0 ​ 13 ​ $ 831,015 ​ $ 16,595 Obligations of state and political subdivisions ​ 1 ​ 358 ​ 0 ​ 0 ​ 0 ​ 0 ​ 1 ​ 358 ​ 0 Government agency mortgage-backed securities ​ 89 ​ 75,992 ​ 182 ​ 2 ​ 14 ​ 0 ​ 91 ​ 76,006 ​ 182 Corporate debt securities ​ 1 ​ ​ 1,001 ​ ​ 1 ​ 0 ​ ​ 0 ​ ​ 0 ​ 1 ​ ​ 1,001 ​ ​ 1 Government agency collateralized mortgage obligations ​ 13 ​ 5,246 ​ 10 ​ 1 ​ 0 ​ 0 ​ 14 ​ 5,246 ​ 10 Total available-for-sale investment portfolio ​ 117 ​ $ 913,612 ​ $ 16,788 ​ 3 ​ $ 14 ​ $ 0 ​ 120 ​ $ 913,626 ​ $ 16,788 ​ 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 carry a credit rating of A or better. Additionally, a portion of the obligations of state and political subdivisions carry a secondary level of credit enhancement. The Company holds one corporate debt security in an unrealized loss position which is currently rated A- or better and the issuer of the security shows a low risk of default. 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. Timely principal and interest payments continue to be made on the securities. 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 December 31, 2021 and 2020 represents credit losses and no unrealized losses have been recognized in the provision for credit losses. Accordingly, there is no allowance for credit losses on the Company’s available-for-sale portfolio as of December 31, 2021 and 2020. The amortized cost and estimated fair value of debt securities at December 31, 2021, 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 ​ ​ Amortized ​ ​ (000’s omitted) Cost Fair Value Due in one year or less ​ $ 156,262 ​ $ 158,119 Due after one through five years ​ 876,849 ​ 891,772 Due after five years through ten years ​ 1,958,202 ​ 1,962,453 Due after ten years ​ 1,494,330 ​ 1,424,471 Subtotal ​ 4,485,643 ​ 4,436,815 Government agency mortgage-backed securities ​ 474,506 ​ 477,056 Government agency collateralized mortgage obligations ​ 19,953 ​ 20,339 Total ​ $ 4,980,102 ​ $ 4,934,210 ​ Investment securities with a carrying value of $2.32 billion and $2.03 billion at December 31, 2021 and 2020, respectively, were pledged to collateralize certain deposits and borrowings. Securities pledged to collateralize certain deposits and borrowings included $485.4 million and $473.4 million of U.S. Treasury securities that were pledged as collateral for securities sold under agreement to repurchase at December 31, 2021 and 2020, respectively. All securities sold under agreement to repurchase as of December 31, 2021 and 2020 have an overnight and continuous maturity. During 2019, the Company sold $590.2 million of U.S. Treasury and agency securities, recognizing $5.0 million of gross realized gains and $0.1 million of gross realized losses. There were no sales of investment securities in 2021 and 2020.

LOANS

LOANS	12 Months Ended
	Dec. 31, 2021
LOANS
LOANS	NOTE D: LOANS The segments of the Company’s loan portfolio at December 31 are summarized as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (000’s omitted) ​ 2021 2020 Business lending ​ $ 3,075,904 ​ $ 3,440,077 Consumer mortgage ​ 2,556,114 ​ 2,401,499 Consumer indirect ​ 1,189,749 ​ 1,021,885 Consumer direct ​ 153,811 ​ 152,657 Home equity ​ 398,061 ​ 399,834 Gross loans, including deferred origination costs ​ 7,373,639 ​ 7,415,952 Allowance for credit losses ​ (49,869) ​ (60,869) Loans, net of allowance for credit losses ​ $ 7,323,770 ​ $ 7,355,083 ​ The Company had approximately $34.9 million and $25.5 million of net deferred loan origination costs included in gross loans as of December 31, 2021 and 2020, respectively. Certain directors and executive officers of the Company, as well as associates of such persons, are loan customers. Loans to these individuals were made in the ordinary course of business under normal credit terms and do not have more than a normal risk of collection. Following is a summary of the aggregate amount of such loans during 2021 and 2020. ​ ​ ​ ​ ​ ​ ​ ​ (000’s omitted) 2021 2020 Balance at beginning of year ​ $ 15,549 ​ $ 17,486 New loans ​ 2,500 ​ 4,194 Payments ​ (4,276) ​ (6,131) Balance at end of year ​ $ 13,773 ​ $ 15,549 ​ The following table presents the aging of the amortized cost basis of the Company’s past due loans, including purchased credit deteriorated (“PCD”) loans, by segment as of December 31, 2021 and 2020: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Past Due ​ 90+ Days Past ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (000’s omitted) ​ 30 – 89 ​ Due and ​ ​ ​ ​ Total ​ ​ ​ ​ ​ ​ December 31, 2021 Days Still Accruing Nonaccrual Past Due Current Total Loans Business lending ​ $ 5,540 ​ $ 99 ​ $ 24,105 ​ $ 29,744 ​ $ 3,046,160 ​ $ 3,075,904 Consumer mortgage ​ 10,297 ​ 3,328 ​ 15,027 ​ 28,652 ​ 2,527,462 ​ 2,556,114 Consumer indirect ​ 9,611 ​ 87 ​ 0 ​ 9,698 ​ 1,180,051 ​ 1,189,749 Consumer direct ​ 796 ​ 22 ​ 1 ​ 819 ​ 152,992 ​ 153,811 Home equity ​ 1,778 ​ 272 ​ 2,532 ​ 4,582 ​ 393,479 ​ 398,061 Total ​ $ 28,022 ​ $ 3,808 ​ $ 41,665 ​ $ 73,495 ​ $ 7,300,144 ​ $ 7,373,639 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Past Due ​ 90+ Days Past ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (000’s omitted) ​ 30 – 89 ​ Due and ​ ​ ​ ​ Total ​ ​ ​ ​ ​ ​ December 31, 2020 Days Still Accruing Nonaccrual Past Due Current Total Loans Business lending ​ $ 4,896 ​ $ 59 ​ $ 55,709 ​ $ 60,664 ​ $ 3,379,413 ​ $ 3,440,077 Consumer mortgage ​ 13,236 ​ 3,051 ​ 14,970 ​ 31,257 ​ 2,370,242 ​ 2,401,499 Consumer indirect ​ 13,161 ​ 219 ​ 1 ​ 13,381 ​ 1,008,504 ​ 1,021,885 Consumer direct ​ 1,170 ​ 28 ​ 3 ​ 1,201 ​ 151,456 ​ 152,657 Home equity ​ 2,296 ​ 565 ​ 2,246 ​ 5,107 ​ 394,727 ​ 399,834 Total ​ $ 34,759 ​ $ 3,922 ​ $ 72,929 ​ $ 111,610 ​ $ 7,304,342 ​ $ 7,415,952 ​ The delinquency status for loans on payment deferment due to COVID-19 financial hardship were reported at December 31, 2021 and 2020 based on their delinquency status at the execution date of the payment deferment, unless subsequent to the execution date of the payment deferment, the borrower made all required past due payments to bring the loan to current status. No interest income on nonaccrual loans was recognized during the years ended December 31, 2021 or 2020. For the year ended December 31, 2021, an immaterial amount of accrued interest was written off on nonaccrual loans by reversing interest income. The Company wrote off $1.5 million of accrued interest on nonaccrual loans by reversing interest income in 2020 primarily due to the reversal of accrued interest on business lending loans of certain commercial borrowers, which primarily operate in the hospitality, travel and entertainment industries, who requested and were granted further extensions of existing loan repayment forbearance due to the continued pandemic-related financial hardship they were experiencing, which were reclassified from accruing to nonaccrual status. Approximately $2.3 million of interest income on loans that returned to accrual status in 2021 was recognized for the year ended December 31, 2021. 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. Loans that were granted COVID-19 related financial hardship payment deferrals were reviewed on a case-by-case basis for credit risk ratings. Loans on payment deferral will continue to be monitored for indications of deterioration that could result in future downgrades. 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. Loss may be incurred at some future date, if conditions deteriorate further. Classified ​ The condition of the borrower has significantly deteriorated and the performance of the loan could further deteriorate and incur loss, 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 and loss is likely. ​ The following tables show the amount of business lending loans by credit quality category at December 31, 2021 and 2020: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Term Loans Amortized Cost Basis by Origination Year ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Revolving ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Loans ​ ​ ​ (000’s omitted) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Amortized ​ ​ ​ December 31, 2021 2021 2020 2019 2018 2017 Prior Cost Basis Total Business lending: ​ ​ ​ ​ ​ ​ ​ ​ Risk rating ​ ​ ​ ​ ​ ​ ​ ​ Pass ​ $ 524,302 ​ $ 328,885 ​ $ 320,638 ​ $ 248,175 ​ $ 186,074 ​ $ 584,912 ​ $ 524,553 ​ $ 2,717,539 Special mention ​ 5,969 ​ 11,013 ​ 10,111 ​ 46,318 ​ 22,524 ​ 57,134 ​ 27,444 ​ 180,513 Classified ​ 1,870 ​ 1,767 ​ 20,315 ​ 40,235 ​ 21,904 ​ 63,685 ​ 27,511 ​ 177,287 Doubtful ​ 0 ​ 0 ​ 0 ​ 62 ​ 0 ​ 0 ​ 503 ​ 565 Total business lending ​ $ 532,141 ​ $ 341,665 ​ $ 351,064 ​ $ 334,790 ​ $ 230,502 ​ $ 705,731 ​ $ 580,011 ​ $ 3,075,904 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Term Loans Amortized Cost Basis by Origination Year ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Revolving ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Loans ​ ​ ​ (000’s omitted) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Amortized ​ ​ ​ December 31, 2020 2020 2019 2018 2017 2016 Prior Cost Basis Total Business lending: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Risk rating ​ ​ ​ ​ ​ ​ ​ ​ ​ Pass ​ $ 860,178 ​ $ 351,350 ​ $ 312,087 ​ $ 217,138 ​ $ 231,453 ​ $ 543,999 ​ $ 483,018 ​ $ 2,999,223 Special mention ​ 14,687 ​ 36,041 ​ 28,410 ​ 21,875 ​ 29,386 ​ 51,657 ​ 52,732 ​ 234,788 Classified ​ 6,336 ​ 4,560 ​ 30,422 ​ 24,807 ​ 14,891 ​ 65,157 ​ 56,000 ​ 202,173 Doubtful ​ 0 ​ 18 ​ 2,888 ​ 0 ​ 0 ​ 108 ​ 879 ​ 3,893 Total business lending ​ $ 881,201 ​ $ 391,969 ​ $ 373,807 ​ $ 263,820 ​ $ 275,730 ​ $ 660,921 ​ $ 592,629 ​ $ 3,440,077 ​ 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 December 31, 2021 and 2020: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Term Loans Amortized Cost Basis by Origination Year ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Revolving ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Loans ​ ​ ​ (000’s omitted) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Amortized ​ ​ ​ December 31, 2021 2021 2020 2019 2018 2017 Prior Cost Basis Total Consumer mortgage: ​ ​ ​ ​ ​ ​ ​ ​ FICO AB ​ ​ ​ ​ ​ ​ ​ ​ Performing ​ $ 514,680 ​ $ 229,039 ​ $ 183,469 ​ $ 113,618 ​ $ 116,417 ​ $ 566,129 ​ $ 0 ​ $ 1,723,352 Nonperforming ​ 0 ​ 266 ​ 0 ​ 131 ​ 435 ​ 3,236 ​ 0 ​ 4,068 Total FICO AB ​ 514,680 ​ 229,305 ​ 183,469 ​ 113,749 ​ 116,852 ​ 569,365 ​ 0 ​ 1,727,420 FICO CDE ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Performing ​ 168,870 ​ 122,546 ​ 85,253 ​ 57,973 ​ 54,396 ​ 300,341 ​ 25,028 ​ 814,407 Nonperforming ​ 0 ​ 522 ​ 972 ​ 1,465 ​ 939 ​ 10,389 ​ 0 ​ 14,287 Total FICO CDE ​ 168,870 ​ 123,068 ​ 86,225 ​ 59,438 ​ 55,335 ​ 310,730 ​ 25,028 ​ 828,694 Total consumer mortgage ​ $ 683,550 ​ $ 352,373 ​ $ 269,694 ​ $ 173,187 ​ $ 172,187 ​ $ 880,095 ​ $ 25,028 ​ $ 2,556,114 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Consumer indirect: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Performing ​ $ 590,857 ​ $ 204,529 ​ $ 182,458 ​ $ 107,683 ​ $ 39,385 ​ $ 64,750 ​ $ 0 ​ $ 1,189,662 Nonperforming ​ 0 ​ 34 ​ 0 ​ 24 ​ 17 ​ 12 ​ 0 ​ 87 Total consumer indirect ​ $ 590,857 ​ $ 204,563 ​ $ 182,458 ​ $ 107,707 ​ $ 39,402 ​ $ 64,762 ​ $ 0 ​ $ 1,189,749 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Consumer direct: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Performing ​ $ 72,584 ​ $ 28,905 ​ $ 24,770 ​ $ 12,340 ​ $ 4,396 ​ $ 4,575 ​ $ 6,218 ​ $ 153,788 Nonperforming ​ 0 ​ 4 ​ 18 ​ 1 ​ 0 ​ 0 ​ 0 ​ 23 Total consumer direct ​ $ 72,584 ​ $ 28,909 ​ $ 24,788 ​ $ 12,341 ​ $ 4,396 ​ $ 4,575 ​ $ 6,218 ​ $ 153,811 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Home equity: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Performing ​ $ 76,041 ​ $ 43,106 ​ $ 35,990 ​ $ 18,824 ​ $ 15,134 ​ $ 35,740 ​ $ 170,422 ​ $ 395,257 Nonperforming ​ 0 ​ 64 ​ 47 ​ 102 ​ 131 ​ 679 ​ 1,781 ​ 2,804 Total home equity ​ $ 76,041 ​ $ 43,170 ​ $ 36,037 ​ $ 18,926 ​ $ 15,265 ​ $ 36,419 ​ $ 172,203 ​ $ 398,061 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Term Loans Amortized Cost Basis by Origination Year ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Revolving ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Loans ​ ​ ​ (000’s omitted) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Amortized ​ ​ ​ December 31, 2020 2020 2019 2018 2017 2016 Prior Cost Basis Total Consumer mortgage: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ FICO AB ​ ​ ​ ​ ​ ​ ​ ​ Performing ​ $ 260,588 ​ $ 227,027 ​ $ 166,638 ​ $ 163,653 ​ $ 160,911 ​ $ 614,976 ​ $ 321 ​ $ 1,594,114 Nonperforming ​ 0 ​ 0 ​ 275 ​ 398 ​ 345 ​ 2,709 ​ 0 ​ 3,727 Total FICO AB ​ 260,588 ​ 227,027 ​ 166,913 ​ 164,051 ​ 161,256 ​ 617,685 ​ 321 ​ 1,597,841 FICO CDE ​ ​ ​ ​ ​ ​ ​ ​ Performing ​ 115,049 ​ 102,788 ​ 80,973 ​ 75,289 ​ 83,214 ​ 314,668 ​ 17,382 ​ 789,363 Nonperforming ​ 0 ​ 1,010 ​ 582 ​ 877 ​ 1,786 ​ 10,040 ​ 0 ​ 14,295 Total FICO CDE ​ 115,049 ​ 103,798 ​ 81,555 ​ 76,166 ​ 85,000 ​ 324,708 ​ 17,382 ​ 803,658 Total consumer mortgage ​ $ 375,637 ​ $ 330,825 ​ $ 248,468 ​ $ 240,217 ​ $ 246,256 ​ $ 942,393 ​ $ 17,703 ​ $ 2,401,499 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Consumer indirect: ​ ​ ​ ​ ​ ​ ​ ​ Performing ​ $ 303,471 ​ $ 305,901 ​ $ 202,373 ​ $ 86,497 ​ $ 61,449 ​ $ 61,975 ​ $ 0 ​ $ 1,021,666 Nonperforming ​ 51 ​ 52 ​ 82 ​ 17 ​ 16 ​ 1 ​ 0 ​ 219 Total consumer indirect ​ $ 303,522 ​ $ 305,953 ​ $ 202,455 ​ $ 86,514 ​ $ 61,465 ​ $ 61,976 ​ $ 0 ​ $ 1,021,885 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Consumer direct: ​ ​ ​ ​ ​ ​ ​ ​ Performing ​ $ 49,181 ​ $ 46,992 ​ $ 27,872 ​ $ 12,326 ​ $ 5,232 ​ $ 4,146 ​ $ 6,878 ​ $ 152,627 Nonperforming ​ 1 ​ 19 ​ 2 ​ 5 ​ 0 ​ 3 ​ 0 ​ 30 Total consumer direct ​ $ 49,182 ​ $ 47,011 ​ $ 27,874 ​ $ 12,331 ​ $ 5,232 ​ $ 4,149 ​ $ 6,878 ​ $ 152,657 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Home equity: ​ ​ ​ ​ ​ ​ ​ ​ Performing ​ $ 48,145 ​ $ 48,780 ​ $ 28,074 ​ $ 23,524 ​ $ 17,828 ​ $ 35,900 ​ $ 194,773 ​ $ 397,024 Nonperforming ​ 0 ​ 24 ​ 73 ​ 104 ​ 183 ​ 490 ​ 1,936 ​ 2,810 Total home equity ​ $ 48,145 ​ $ 48,804 ​ $ 28,147 ​ $ 23,628 ​ $ 18,011 ​ $ 36,390 ​ $ 196,709 ​ $ 399,834 ​ All loan classes are collectively assessed for impairment except business lending. A summary of individually assessed business lending loans as of December 31, 2021 and 2020 follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ December 31, (000’s omitted) 2021 2020 Loans with allowance allocation ​ $ 7,102 ​ $ 27,437 Loans without allowance allocation ​ 7,417 ​ 8,138 Carrying balance ​ 14,519 ​ 35,575 Contractual balance ​ 16,963 ​ 38,362 Specifically allocated allowance ​ 566 ​ 3,874 ​ The average carrying balance of individually assessed loans was $33.4 million, and $12.2 million for the years ended December 31, 2021 and 2020, respectively. No interest income was recognized on individually assessed loans for the years ended December 31, 2021 and 2020. 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 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 clarified guidance issued by the 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 2021 and 2020 was immaterial. TDRs less than $0.5 million are collectively included in the allowance for credit loss estimate. Commercial loans greater than $0.5 million are individually assessed, and if necessary, a specific allocation of the allowance for credit losses is provided. With regard to determination of the amount of the allowance for credit losses, troubled debt restructured loans are considered to be impaired. As a result, the determination of the amount of allowance for credit losses related to individually assessed loans for each portfolio segment within TDRs is the same as detailed previously. With respect to the Company’s lending activities, the Company implemented a customer forbearance program allowing for loan payment deferrals up to three months per request during 2020 to assist both consumer and business borrowers that were experiencing financial hardship due to COVID-19 related challenges. Business lending, consumer direct, and consumer indirect loans in deferment status continued to accrue interest on the deferred principal during the deferment period unless otherwise classified as nonaccrual. Consumer mortgage and home equity loans did not accrue interest on the deferred payments during the deferment period. Consistent with the Coronavirus Aid, Relief and Economic Security Act (“CARES Act”), the Consolidated Appropriations Act of 2021 (“CAA”), and industry regulatory guidance, borrowers that were otherwise current on loan payments and granted COVID-19 related financial hardship payment deferrals were reported as current loans throughout the first 180 days of the deferral period and were not classified as TDRs. Borrowers that were delinquent in their payments to the Bank prior to requesting a COVID-19 related financial hardship payment deferral were reviewed on a case-by-case basis for TDR classification and non-performing loan status. As of December 31, 2021, the Company had 5 borrowers in forbearance due to COVID-19 related financial hardship, representing $4.2 million in outstanding loan balances, or 0.1 % of total loans outstanding. These forbearances were comprised of 4 business borrowers representing $4.1 million in outstanding loan balances and 1 consumer borrower representing approximately $0.1 million in outstanding loan balances. Information regarding TDRs as of December 31, 2021 and 2020 is as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2021 December 31, 2020 (000’s omitted) ​ Nonaccrual ​ Accruing ​ Total ​ Nonaccrual ​ Accruing ​ Total ​ # Amount # Amount # Amount # Amount # Amount # Amount Business lending ​ 10 ​ $ 1,011 4 ​ $ 811 14 ​ $ 1,822 6 ​ $ 529 4 ​ $ 191 10 ​ $ 720 Consumer mortgage ​ 61 ​ 2,694 47 ​ 2,420 108 ​ 5,114 56 ​ 2,413 48 ​ 2,266 104 ​ 4,679 Consumer indirect ​ 0 ​ 0 72 ​ 829 72 ​ 829 0 ​ 0 86 ​ 951 86 ​ 951 Consumer direct ​ 0 ​ 0 16 ​ 7 16 ​ 7 0 ​ 0 23 ​ 85 23 ​ 85 Home equity ​ 10 ​ 235 12 ​ 232 22 ​ 467 11 ​ 285 13 ​ 264 24 ​ 549 Total ​ 81 ​ $ 3,940 151 ​ $ 4,299 232 ​ $ 8,239 73 ​ $ 3,227 174 ​ $ 3,757 247 ​ $ 6,984 ​ The following table presents information related to loans modified in a TDR during the years ended December 31, 2021 and 2020. Of the loans noted in the table below, all consumer mortgage loans for the years ended December 31, 2021 and 2020 were modified due to a Chapter 7 bankruptcy as described previously. The financial effects of these restructurings were immaterial. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2021 December 31, 2020 (000’s omitted) # Amount # Amount Business lending ​ 5 ​ $ 1,371 ​ 1 ​ $ 4 Consumer mortgage ​ 24 ​ ​ 1,425 ​ 17 ​ 1,339 Consumer indirect ​ 23 ​ ​ 284 ​ 31 ​ 333 Consumer direct ​ 2 ​ ​ 7 ​ 3 ​ 10 Home equity ​ 0 ​ ​ 0 ​ 3 ​ 70 Total ​ 54 ​ $ 3,087 ​ 55 ​ $ 1,756 ​ Allowance for Credit Losses The following presents by segment the activity in the allowance for credit losses during 2021 and 2020: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended December 31, 2021 ​ Beginning Charge- ​ Ending (000’s omitted) ​ balance ​ offs ​ Recoveries ​ Provision ​ balance Business lending ​ $ 28,190 ​ $ (1,618) ​ $ 689 ​ $ (6,240) ​ $ 21,021 Consumer mortgage ​ 10,672 ​ (426) ​ 91 ​ (320) ​ 10,017 Consumer indirect ​ 13,696 ​ (5,160) ​ 4,346 ​ (1,145) ​ 11,737 Consumer direct ​ 3,207 ​ (1,232) ​ 793 ​ (462) ​ 2,306 Home equity ​ 2,222 ​ (225) ​ 92 ​ (275) ​ 1,814 Unallocated ​ 1,000 ​ 0 ​ 0 ​ 0 ​ 1,000 Purchased credit deteriorated ​ 1,882 ​ (304) ​ 107 ​ 289 ​ 1,974 Allowance for credit losses – loans ​ 60,869 ​ (8,965) ​ 6,118 ​ (8,153) ​ 49,869 Liabilities for off-balance-sheet credit exposures ​ 1,489 ​ 0 ​ 0 ​ (686) ​ 803 Total allowance for credit losses ​ $ 62,358 ​ $ (8,965) ​ $ 6,118 ​ $ (8,839) ​ $ 50,672 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended December 31, 2020 ​ ​ Beginning ​ ​ ​ ​ Beginning ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ balance, ​ ​ ​ ​ balance, ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ prior to the ​ ​ ​ ​ after ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ adoption of ​ Impact of ​ adoption of ​ Charge- ​ ​ ​ ​ Steuben ​ ​ ​ ​ Ending (000’s omitted) ​ ASC 326 ASC 326 ASC 326 offs Recoveries acquisition Provision balance Business lending ​ $ 19,426 ​ $ 288 ​ $ 19,714 ​ $ (1,497) ​ $ 356 ​ $ 2,343 ​ $ 7,274 ​ $ 28,190 Consumer mortgage ​ 10,269 ​ (1,051) ​ 9,218 ​ (862) ​ 130 ​ 146 ​ 2,040 ​ 10,672 Consumer indirect ​ 13,712 ​ (997) ​ 12,715 ​ (6,382) ​ 3,992 ​ 183 ​ 3,188 ​ 13,696 Consumer direct ​ 3,255 ​ (643) ​ 2,612 ​ (1,633) ​ 743 ​ 87 ​ 1,398 ​ 3,207 Home equity ​ 2,129 ​ 808 ​ 2,937 ​ (199) ​ 28 ​ 235 ​ (779) ​ 2,222 Unallocated ​ 957 ​ 43 ​ 1,000 ​ 0 ​ 0 ​ 0 ​ 0 ​ 1,000 Purchased credit deteriorated ​ 0 ​ 3,072 ​ 3,072 ​ (91) ​ 440 ​ 668 ​ (2,207) ​ 1,882 Acquired impaired ​ 163 ​ (163) ​ 0 ​ 0 ​ 0 ​ 0 ​ 0 ​ 0 Allowance for credit losses – loans ​ 49,911 ​ 1,357 ​ 51,268 ​ (10,664) ​ 5,689 ​ 3,662 ​ 10,914 ​ 60,869 Liabilities for off-balance-sheet credit exposures ​ 0 ​ 1,185 ​ 1,185 ​ 0 ​ 0 ​ 67 ​ 237 ​ 1,489 Total allowance for credit losses ​ $ 49,911 ​ $ 2,542 ​ $ 52,453 ​ $ (10,664) ​ $ 5,689 ​ $ 3,729 ​ $ 11,151 ​ $ 62,358 ​ The allowance for credit losses to total loans ratio of 0.68% at December 31, 2021 was 14 basis points lower than the level at December 31, 2020. This decrease was primarily due to improvements in the economic forecasts and improvements in non-economic qualitative adjustments resulting from lower levels of delinquencies, deferrals, and chargeoffs than in the prior year. Accrued interest receivable on loans, included in accrued interest and fees receivable on the consolidated statements of condition, totaled $16.7 million and $22.2 million at December 31, 2021 and 2020, respectively, and is excluded from the estimate of credit losses and amortized cost basis of loans. Under ASU No. 2016-13, Financial Instruments – Credit Losses (Topic 326) , also referred to as CECL, the Company utilizes the historical loss rate on its loan portfolio as the initial basis for the estimate of credit losses using the cumulative loss, vintage loss and line loss methods which is derived from the Company’s historical loss experience from January 1, 2012 to December 31, 2020. Adjustments to historical loss experience were made for differences in current loan-specific risk characteristics and to address current period delinquencies, charge-off rates, risk ratings, lack of loan level data through an entire economic cycle, changes in loan sizes and underwriting standards as well as the addition of acquired loans which were not underwritten by the Company. The Company considered historical losses immediately prior, through and following the Great Recession of 2008 compared to the historical period used for modeling to adjust the historical information to account for longer-term expectations for loan credit performance. Under CECL, the Company is required to consider future economic conditions to determine current expected credit losses. Management selected an eight quarter reasonable and supportable forecast period using a two quarter lag adjustment for economic factors that are not dependent on collateral values, and no lag for factors that do utilize collateral values, with a four quarter reversion to the historical mean, to use as part of the economic forecast. Management determined that these qualitative adjustments were needed to adjust historical information for expected losses and to reflect changes as a result of current conditions. For qualitative macroeconomic adjustments, the Company uses third party forecasted economic data scenarios utilizing a base scenario and two alternative scenarios that were weighted based on guidance from the third party provider, with forecasts available as of December 31, 2021. These forecasts were factored into the qualitative portion of the calculation of the estimated credit losses and included the continued impact of COVID-19, such as supply chain pressures and their impact on collateral values and economic growth. The scenarios utilized forecast a generally positive outlook on the economy, with low unemployment figures and high collateral values for housing, commercial real estate, and vehicles. In addition to the economic forecast, the Company also considered additional qualitative adjustments as a result of COVID-19 and the impact on all industries, loan deferrals, delinquencies and downgrades. Management developed expected loss estimates considering factors for segments as outlined below: ● Business lending – non real estate: The Company selected projected unemployment and GDP as indicators of forecasted losses related to business lending and utilize both factors in an even weight for the calculation. The Company also considered delinquencies, the level of loan deferrals, risk rating changes, recent charge-off history and acquired loans as part of the review of estimated losses. ● Business lending – real estate: The Company selected projected unemployment and commercial real estate values as indicators of forecasted losses related to commercial real estate loans and utilize both factors in an even weight for the calculation. The Company also considered the factors noted in business lending – non real estate. ● Consumer mortgages and home equity: The Company selected projected unemployment and residential real estate values as indicators of forecasted losses related to mortgage lending and utilize both factors in an even weight for the calculation. In addition, current delinquencies, the level of loan deferrals, charge-offs and acquired loans were considered. ● Consumer indirect: The Company selected projected unemployment and vehicle valuation indices as indicators of forecasted losses related to indirect lending and utilize both factors in an even weight for the calculation. In addition, current delinquencies, the level of loan deferrals, charge-offs and acquired loans were considered. ● Consumer direct: The Company selected projected unemployment and household income as indicators of forecasted losses related to consumer direct lending and utilize both factors in an even weight for the calculation. In addition, current delinquencies, the level of loan deferrals, charge-offs and acquired loans were considered. The following table presents the carrying amounts of loans purchased and sold during the year ended December 31, 2021 by portfolio segment: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (000’s Business Consumer Consumer Consumer Home ​ omitted) ​ lending ​ mortgage ​ indirect ​ direct ​ equity ​ Total Purchases ​ $ 0 ​ $ 0 ​ $ 0 ​ $ 0 ​ $ 0 ​ $ 0 Sales ​ 3,748 ​ 20,133 ​ 0 ​ 0 ​ 0 ​ 23,881 ​ All the sales of consumer mortgages during the year ended December 31, 2021 were sales of secondary market eligible residential mortgage loans. The sales of business loans during the year ended December 31, 2021 includes three business lending loans under two relationships.

PREMISES AND EQUIPMENT

PREMISES AND EQUIPMENT	12 Months Ended
	Dec. 31, 2021
PREMISES AND EQUIPMENT
PREMISES AND EQUIPMENT	NOTE E: PREMISES AND EQUIPMENT Premises and equipment consist of the following at December 31: ​ ​ ​ ​ ​ ​ ​ ​ (000’s omitted) 2021 2020 Land and land improvements ​ $ 31,884 ​ $ 29,070 Bank premises ​ 151,724 ​ 149,217 Equipment ​ 85,391 ​ 93,013 Operating lease right-of-use assets ​ 31,754 ​ 34,908 Construction in progress ​ ​ 4,786 ​ ​ 6,226 Premises and equipment, gross ​ 305,539 ​ 312,434 Accumulated depreciation ​ (144,888) ​ (146,779) Premises and equipment, net ​ $ 160,651 ​ $ 165,655 ​

GOODWILL AND IDENTIFIABLE INTAN

GOODWILL AND IDENTIFIABLE INTANGIBLE ASSETS	12 Months Ended
	Dec. 31, 2021
GOODWILL AND IDENTIFIABLE INTANGIBLE ASSETS
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: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2021 December 31, 2020 ​ ​ Gross ​ ​ ​ ​ Net ​ Gross ​ ​ ​ ​ Net ​ Carrying Accumulated Carrying Carrying Accumulated Carrying (000’s omitted) ​ Amount Amortization Amount Amount Amortization Amount Amortizing intangible assets: ​ ​ ​ ​ ​ ​ ​ Core deposit intangibles ​ $ 69,403 ​ $ (60,316) ​ $ 9,087 ​ $ 69,403 ​ $ (55,572) ​ $ 13,831 Other intangibles ​ 116,799 ​ (60,660) ​ 56,139 ​ 90,462 ​ (51,353) ​ 39,109 Total amortizing intangibles ​ $ 186,202 ​ $ (120,976) ​ $ 65,226 ​ $ 159,865 ​ $ (106,925) ​ $ 52,940 ​ The estimated aggregate amortization expense for each of the five succeeding fiscal years ended December 31 is as follows (000’s omitted): ​ ​ ​ ​ ​ Year Amount 2022 ​ $ 13,668 2023 ​ ​ 11,595 2024 ​ 9,782 2025 ​ 8,349 2026 ​ 7,494 Thereafter ​ 14,338 Total ​ $ 65,226 ​ Shown below are the components of the Company’s goodwill at December 31, 2021, 2020, and 2019: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ ​ ​ ​ December 31, ​ ​ ​ ​ December 31, (000’s omitted) ​ 2019 Activity 2020 Activity 2021 Goodwill, net ​ $ 773,810 ​ $ 19,898 ​ $ 793,708 ​ $ 5,401 ​ $ 799,109 ​ During 2021, the Company performed quarterly qualitative analyses of goodwill impairment and performed a quantitative assessment of its banking and financial services businesses during the fourth quarter of 2021 by comparing the fair value of the reporting unit with its carrying amount. The qualitative analyses performed in 2021 included assessments of macroeconomic conditions, industry and market considerations, cost factors, overall financial performance, other relevant entity-specific events, events affecting a reporting unit and changes in share price. During 2020, the Company performed quarterly qualitative analyses of goodwill impairment and performed a quantitative assessment of its insurance subsidiary included in the All Other segment during the fourth quarter of 2020. Results of the quarterly and annual analyses indicate there was no goodwill impairment in 2021 or 2020. Mortgage Servicing Rights Under certain circumstances, the Company sells consumer residential mortgage loans in the secondary market and typically retains the right to service the loans sold. Generally, the Company’s residential mortgage loans sold to third parties are sold on a non-recourse basis. Upon sale, a mortgage servicing right (“MSR”) is established, which represents the current fair value of future net cash flows expected to be realized for performing the servicing activities. The Company stratifies these assets based on predominant risk characteristics, namely expected term of the underlying financial instruments, and uses a valuation model that calculates the present value of future cash flows to determine the fair value of servicing rights. MSRs are recorded in other assets at the lower of the initial capitalized amount, net of accumulated amortization or fair value. Mortgage loans serviced for others are not included in the accompanying consolidated statements of condition. The following table summarizes the changes in carrying value of MSRs and the associated valuation allowance: ​ ​ ​ ​ ​ ​ ​ ​ (000’s omitted) ​ 2021 ​ 2020 Carrying value before valuation allowance at beginning of period ​ $ 1,430 ​ $ 972 Additions ​ 233 ​ 715 Acquisitions ​ 0 ​ 122 Amortization ​ (519) ​ (379) Carrying value before valuation allowance at end of period ​ 1,144 ​ 1,430 Valuation allowance balance at beginning of period ​ (219) ​ (298) Impairment charges ​ (55) ​ (150) Impairment recoveries ​ 274 ​ 229 Valuation allowance balance at end of period ​ 0 ​ (219) Net carrying value at end of period ​ $ 1,144 ​ $ 1,211 Fair value of MSRs at end of period ​ $ 1,469 ​ $ 1,384 Principal balance of mortgage loans sold during the year ​ $ 20,133 ​ $ 79,709 Principal balance of loans serviced for others ​ $ 296,506 ​ $ 351,759 Custodial escrow balances maintained in connection with loans serviced for others ​ $ 4,934 ​ $ 5,583 ​ The following table summarizes the key economic assumptions used to estimate the value of the MSRs at December 31: ​ ​ ​ ​ ​ ​ ​ ​ ​ 2021 ​ 2020 Weighted-average contractual life (in years) 21.4 21.5 ​ Weighted-average constant prepayment rate (CPR) 24.5 % 30.4 % Weighted-average discount rate 2.6 % 2.1 % ​

DEPOSITS

DEPOSITS	12 Months Ended
	Dec. 31, 2021
DEPOSITS.
DEPOSITS	NOTE G: DEPOSITS Deposits recorded in the consolidated statements of condition consist of the following at December 31: ​ ​ ​ ​ ​ ​ ​ ​ (000’s omitted) ​ 2021 ​ 2020 Noninterest checking ​ $ 3,921,663 ​ $ 3,361,768 Interest checking ​ 3,201,225 ​ 2,876,420 Savings ​ 2,255,961 ​ 1,949,517 Money market ​ 2,603,988 ​ 2,103,498 Time ​ 928,331 ​ 933,771 Total deposits ​ $ 12,911,168 ​ $ 11,224,974 ​ Interest on deposits recorded in the consolidated statements of income consists of the following at December 31: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (000’s omitted) ​ 2021 ​ 2020 ​ 2019 Interest on interest checking ​ $ 1,142 ​ $ 2,182 ​ $ 3,678 Interest on savings ​ 598 ​ 665 ​ 942 Interest on money market ​ 1,393 ​ 2,685 ​ 5,836 Interest on time ​ 8,498 ​ 11,229 ​ 10,004 Total interest on deposits ​ $ 11,631 ​ $ 16,761 ​ $ 20,460 ​ The approximate maturities of time deposits at December 31, 2021 are as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Accounts $250,000 (000’s omitted) ​ All Accounts ​ or Greater 2022 ​ $ 579,595 ​ $ 186,647 2023 ​ 139,881 ​ 7,408 2024 ​ 162,317 ​ 38,681 2025 ​ 21,494 ​ 2,102 2026 ​ 25,010 ​ 1,922 Thereafter ​ 34 ​ 0 Total ​ $ 928,331 ​ $ 236,760 ​

BORROWINGS

BORROWINGS	12 Months Ended
	Dec. 31, 2021
BORROWINGS
BORROWINGS	NOTE H: BORROWINGS Outstanding borrowings at December 31 are as follows: ​ ​ ​ ​ ​ ​ ​ ​ (000’s omitted) ​ 2021 ​ 2020 Subordinated notes payable, includes premium of $277 and $303, respectively ​ $ 3,277 ​ $ 3,303 Subordinated debt held by unconsolidated subsidiary trusts ​ 0 ​ 77,320 Securities sold under agreement to repurchase, short term ​ 324,720 ​ 284,008 Other FHLB borrowings ​ 1,888 ​ 6,658 Total borrowings ​ $ 329,885 ​ $ 371,289 ​ FHLB advances are collateralized by a blanket lien on the Company's residential real estate loan portfolio and various investment securities. Borrowings at December 31, 2021 have contractual maturity dates as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted-average ​ ​ Carrying ​ Rate at (000’s omitted, except rate) ​ Value ​ December 31, 2021 January 2, 2022 ​ $ 324,720 0.27 % February 8, 2023 ​ 190 1.79 % July 3, 2023 ​ 497 2.25 % October 23, 2023 ​ 395 1.50 % October 1, 2025 ​ 275 1.50 % February 28, 2028 ​ 3,277 4.67 % March 1, 2029 ​ 531 2.50 % Total ​ $ 329,885 0.32 % ​ The weighted-average interest rate on borrowings for the years ended December 31, 2021 and 2020 was 0.48% and 1.27%, respectively. As of December 31, 2021, the Company does not sponsor any business trusts. The Company previously sponsored Community Capital Trust IV (“CCT IV”) until March 15, 2021 when the Company exercised its right to redeem all of the CCT IV debentures and associated preferred securities for a total of $77.3 million. The Company previously sponsored Steuben Statutory Trust II (“SST II”) until September 15, 2020 when the Company exercised its right to redeem all of the SST II debentures and associated preferred securities for a total of $2.1 million. The common stock of SST II was acquired in the Steuben acquisition. 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 were the sole assets of such trust. Distributions on the preferred securities issued by each trust were 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 were recorded as interest expense in the consolidated financial statements. The preferred securities were subject to mandatory redemption, in whole or in part, upon repayment of the debentures. The Company had entered into agreements which, taken collectively, fully and unconditionally guarantee the preferred securities subject to the terms of each of the guarantees.

INCOME TAXES

INCOME TAXES	12 Months Ended
	Dec. 31, 2021
INCOME TAXES
INCOME TAXES	NOTE I: INCOME TAXES The provision for income taxes for the years ended December 31 is as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (000’s omitted) 2021 2020 2019 Current: ​ ​ ​ Federal ​ $ 35,507 ​ $ 35,728 ​ $ 34,804 State and other ​ 8,158 ​ 8,008 ​ 7,773 Deferred: ​ ​ ​ ​ Federal ​ 5,493 ​ (2,005) ​ (699) State and other ​ 2,496 ​ (331) ​ (1,603) Provision for income taxes ​ $ 51,654 ​ $ 41,400 ​ $ 40,275 ​ Components of the net deferred tax liability, included in other liabilities, as of December 31 are as follows: ​ ​ ​ ​ ​ ​ ​ ​ (000’s omitted) 2021 2020 Allowance for credit losses ​ $ 12,435 ​ $ 15,004 Employee benefits ​ 7,708 ​ 7,552 Operating lease liabilities ​ 7,955 ​ 8,601 Other, net ​ 1,250 ​ 900 Deferred tax asset ​ 29,348 ​ 32,057 ​ ​ ​ ​ ​ ​ ​ Investment securities ​ 7,227 ​ 43,325 Goodwill and intangibles ​ 41,917 ​ 40,802 Operating lease right-of-use assets ​ 7,693 ​ 8,384 Loan origination costs ​ 8,993 ​ 7,904 Depreciation ​ 535 ​ 3,089 Mortgage servicing rights ​ 278 ​ 291 Pension ​ 22,950 ​ 16,987 Deferred tax liability ​ 89,593 ​ 120,782 Net deferred tax liability ​ $ (60,245) ​ $ (88,725) ​ The Company has determined that no valuation allowance is necessary as it is more likely than not that the gross deferred tax assets will be realized through future reversals of existing temporary differences and through future taxable income. A reconciliation of the differences between the federal statutory income tax rate and the effective tax rate for the years ended December 31 is shown in the following table: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2021 2020 2019 Federal statutory income tax rate 21.0 % 21.0 % 21.0 % Increase (reduction) in taxes resulting from: ​ ​ Tax-exempt interest (1.1) (1.5) (1.5) ​ State income taxes, net of federal benefit 3.6 3.0 2.5 ​ Stock-based compensation (0.9) (0.8) (1.6) ​ Federal tax credits (1.0) (1.3) (1.3) ​ Other, net (0.2) (0.3) 0.1 ​ Effective income tax rate 21.4 % 20.1 % 19.2 % ​ As of December 31, 2021, 2020 and 2019, there was no amount of material unrecognized tax benefits that would impact the Company’s effective tax rate if recognized. It is reasonably possible that the amount of unrecognized tax benefits could change in the next twelve months as a result of various examinations and expiration of statutes of limitations on prior tax returns. The Company’s policy is to recognize interest and penalties related to unrecognized tax benefits as part of income taxes in the consolidated statement of income. The accrued interest related to tax positions was immaterial. The Company’s federal and state income tax returns are routinely subject to examination from various governmental taxing authorities. Such examinations may result in challenges to the tax return treatment applied by the Company to specific transactions. Management believes that the assumptions and judgment used to record tax-related assets or liabilities have been appropriate. Future examinations by taxing authorities of the Company’s federal or state tax returns could have a material impact on the Company’s results of operations. The Company’s federal income tax returns for years after 2017 may still be examined by the Internal Revenue Service. New York State income tax returns for years after 2017 may still be examined by the New York Department of Taxation and Finance. The Company is currently under examination by the Massachusetts Department of Revenue in connection with tax years 2018 to 2019 and the New York Department of Taxation and Finance in connection with tax years 2015 to 2017, and has not received any notices of proposed adjustments. It is not possible to estimate if and when those examinations may be completed.

LIMITS ON DIVIDENDS AND OTHER R

LIMITS ON DIVIDENDS AND OTHER REVENUE SOURCES	12 Months Ended
	Dec. 31, 2021
LIMITS ON DIVIDENDS AND OTHER REVENUE SOURCES
LIMITS ON DIVIDENDS AND OTHER REVENUE SOURCES	NOTE J: LIMITS ON DIVIDENDS AND OTHER REVENUE SOURCES The Company’s ability to pay dividends to its shareholders is largely dependent on the Bank’s ability to pay dividends to the Company. In addition to the capital requirements discussed below, the circumstances under which the Bank may pay dividends are limited by federal statutes, regulations, and policies. For example, as a national bank, the Bank must obtain the approval of the Office of the Comptroller of the Currency (“OCC”) for payments of dividends if the total of all dividends declared in any calendar year would exceed the total of the Bank’s net profits, as defined by applicable regulations, for that year, combined with its retained net profits for the preceding two years. Furthermore, the Bank may not pay a dividend in an amount greater than its undivided profits then on hand after deducting its losses and bad debts, as defined by applicable regulations. At December 31, 2021, the Bank had approximately $94.2 million in undivided profits legally available for the payment of dividends. In addition, the Board of Governors of the Federal Reserve System (“FRB”) and the OCC are authorized to determine under certain circumstances that the payment of dividends would be an unsafe or unsound practice and to prohibit payment of such dividends. The FRB has indicated that banking organizations should generally pay dividends only out of current operating earnings. There are also statutory limits on the transfer of funds to the Company by its banking subsidiary, whether in the form of loans or other extensions of credit, investments or assets purchases. Such transfer by the Bank to the Company generally is limited in amount to 10% of the Bank’s capital and surplus, or 20 % in the aggregate. Furthermore, such loans and extensions of credit are required to be collateralized in specific amounts.

BENEFIT PLANS

BENEFIT PLANS	12 Months Ended
	Dec. 31, 2021
BENEFIT PLANS
BENEFIT PLANS	NOTE K: BENEFIT PLANS Pension and post-retirement 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 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Pension Benefits ​ Post-retirement Benefits (000’s omitted) 2021 2020 2021 2020 Change in benefit obligation: ​ ​ ​ ​ Benefit obligation at the beginning of year ​ $ 190,361 ​ $ 162,084 ​ $ 1,718 ​ $ 1,677 Service cost ​ 5,920 ​ 5,750 ​ 0 ​ 0 Interest cost ​ 5,036 ​ 5,657 ​ 44 ​ 57 Plan amendment / acquisition ​ 0 ​ 13,598 ​ 0 ​ 0 Participant contributions ​ 0 ​ 0 ​ 0 ​ 0 Deferred actuarial (gain)/loss ​ (4,881) ​ 13,954 ​ (85) ​ 114 Benefits paid ​ (13,166) ​ (10,682) ​ (148) ​ (130) Benefit obligation at end of year ​ 183,270 ​ 190,361 ​ 1,529 ​ 1,718 Change in plan assets: ​ ​ ​ ​ ​ ​ ​ ​ Fair value of plan assets at beginning of year ​ 272,600 ​ 227,323 ​ 0 ​ 0 Actual return of plan assets ​ 27,614 ​ 33,543 ​ 0 ​ 0 Participant contributions ​ 0 ​ 0 ​ 0 ​ 0 Employer contributions ​ 3,639 ​ 7,993 ​ 148 ​ 130 Plan acquisition ​ 0 ​ 14,423 ​ 0 ​ 0 Benefits paid ​ (13,166) ​ (10,682) ​ (148) ​ (130) Fair value of plan assets at end of year ​ 290,687 ​ 272,600 ​ 0 ​ 0 Over/(Under) funded status at year end ​ $ 107,417 ​ $ 82,239 ​ $ (1,529) ​ $ (1,718) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Amounts recognized in the consolidated statement of condition were: ​ ​ ​ ​ Other assets ​ $ 127,538 ​ $ 101,849 ​ $ 0 ​ $ 0 Other liabilities ​ (20,121) ​ (19,610) ​ (1,529) ​ (1,718) Amounts recognized in accumulated other comprehensive loss/(income) (“AOCI”) were: ​ ​ ​ ​ Net loss ​ $ 16,977 ​ $ 34,290 ​ $ 585 ​ $ 715 Net prior service cost (credit) ​ 3,969 ​ 4,348 ​ (907) ​ (1,086) Pre-tax AOCI ​ 20,946 ​ 38,638 ​ (322) ​ (371) Taxes ​ (5,236) ​ (9,488) ​ 82 ​ 94 AOCI at year end ​ $ 15,710 ​ $ 29,150 ​ $ (240) ​ $ (277) ​ The benefit obligation for the defined benefit pension plan was $163.1 million and $170.8 million as of December 31, 2021 and 2020, respectively, and the fair value of plan assets as of December 31, 2021 and 2020 was $290.7 million and $272.6 million, respectively. The defined benefit pension plan was amended effective December 31, 2020 to transfer certain obligations from the Company’s deferred compensation plan and Restoration Plan (as defined below) into the qualified defined benefit pension plan. Effective December 31, 2020, the Steuben Trust Company 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 $1.1 million, due primarily to a gain on plan assets as of the valuation date. The Company has unfunded supplemental pension plans for certain key active and retired executives. The projected benefit obligation for the unfunded supplemental pension plan for certain key executives was $19.8 million and $19.6 million for 2021 and 2020, respectively. The Company also has an unfunded stock balance plan for certain of its nonemployee directors. The projected benefit obligation for the unfunded stock balance plan was immaterial for 2021 and 2020, respectively. The Company has a non-qualified deferred compensation plan for certain employees (“Restoration Plan”) whose benefits under tax-qualified retirement plans are restricted by the Internal Revenue Code Section 401(a)(17) limitation on compensation. The Restoration Plan was amended effective December 31, 2020 to transfer certain obligations into the Company’s qualified defined benefit pension plan. The projected benefit obligation for the unfunded Restoration Plan was $0.03 million for 2021 and $0.03 million for 2020, respectively. Effective December 31, 2009, the Company terminated its post-retirement medical program for current and future employees. Remaining plan participants will include only existing retirees as of December 31, 2010. This change was accounted for as a negative plan amendment and a $3.5 million, net of income taxes, benefit for prior service was recognized in AOCI in 2009. This negative plan amendment is being amortized over the expected benefit utilization period of remaining plan participants. Amounts recognized in accumulated other comprehensive income, net of tax, for the year ended December 31, are as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Pension Benefits ​ Post-retirement Benefits (000’s omitted) 2021 2020 2021 2020 Prior service cost/(credit) ​ $ (288) ​ $ 222 ​ $ 136 ​ $ 136 Net (gain) loss ​ (13,152) ​ (6,423) ​ (99) ​ 56 Total ​ $ (13,440) ​ $ (6,201) ​ $ 37 ​ $ 192 ​ The weighted-average assumptions used to determine the benefit obligations as of December 31 are as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Pension Benefits ​ Post-retirement Benefits ​ 2021 2020 2021 2020 Discount rate 3.10 % 2.80 % 3.10 % 2.80 % Expected return on plan assets 6.70 % 7.00 % N/A N/A ​ Rate of compensation increase ​ 4.00% for 2022 ​ 3.50 % N/A ​ N/A ​ ​ 3.50% for 2023 + ​ ​ ​ ​ ​ Interest crediting rates ​ 6.00% while employed, ​ 6.00% while employed, ​ N/A ​ N/A ​ ​ ​ 1.94% after termination ​ 1.42% after termination ​ ​ ​ ​ ​ ​ The net periodic benefit cost as of December 31 is as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Pension Benefits ​ Post-retirement Benefits (000’s omitted) 2021 2020 2019 2021 2020 2019 Service cost ​ $ 5,920 ​ $ 5,750 ​ $ 5,081 ​ $ 0 ​ $ 0 ​ $ 0 Interest cost ​ 5,036 ​ 5,657 ​ 6,264 ​ 44 ​ 57 ​ 70 Expected return on plan assets ​ (18,783) ​ (16,306) ​ (14,311) ​ 0 ​ 0 ​ 0 Plan amendment ​ 0 ​ (637) ​ 0 ​ 0 ​ 0 ​ 0 Amortization of unrecognized net loss ​ 3,600 ​ 3,239 ​ 2,568 ​ 45 ​ 40 ​ 38 Amortization of prior service cost ​ 379 ​ 241 ​ 64 ​ (179) ​ (179) ​ (179) Net periodic (benefit) ​ $ (3,848) ​ $ 2,056 ​ $ (334) ​ $ (90) ​ $ (82) ​ $ (71) ​ Prior service costs in which all or almost all of the plan’s participants are fully eligible for benefits under the plan are amortized on a straight-line basis over the expected future working years of all active plan participants. Unrecognized gains or losses are amortized using the “corridor approach”, which is the minimum amortization required. Under the corridor approach, the net gain or loss in excess of 10 percent of the greater of the projected benefit obligation or the market-related value of the assets is amortized on a straight-line basis over the expected future working years of all active plan participants. The weighted-average assumptions used to determine the net periodic pension cost for the years ended December 31 are as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Pension Benefits ​ Post-retirement Benefits ​ 2021 2020 2019 2021 2020 2019 Discount rate 2.80 % 3.50 % 4.50 % 2.80 % 3.60 % 4.45 % Expected return on plan assets 7.00 % 7.00 % 7.00 % N/A N/A N/A ​ Rate of compensation increase 3.50 % 3.50 % 3.50 % N/A N/A N/A ​ Interest crediting rates ​ 6.00% while employed, ​ 6.00% while employed ​ 6.00% while employed ​ N/A ​ N/A ​ N/A ​ ​ ​ 1.42% after termination ​ 2.16% after termination ​ 3.15% after termination ​ ​ ​ ​ ​ ​ ​ ​ The amount of benefit payments that are expected to be paid over the next ten years are as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Pension ​ ​ Post-retirement (000’s omitted) ​ Benefits ​ Benefits 2022 ​ $ 10,940 ​ $ 151 2023 ​ 11,863 ​ 119 2024 ​ 12,185 ​ 117 2025 ​ 11,991 ​ 115 2026 ​ 13,567 ​ 113 2027-2031 ​ 63,874 ​ 522 ​ The payments reflect future service and are based on various assumptions including retirement age and form of payment (lump-sum versus annuity). Actual results may differ from these estimates. The assumed discount rate is used to reflect the time value of future benefit obligations. The discount rate was determined based upon the yield on high-quality fixed income investments expected to be available during the period to maturity of the pension benefits. This rate is sensitive to changes in interest rates. A decrease in the discount rate would increase the Company’s obligation and future expense while an increase would have the opposite effect. The expected long-term rate of return was estimated by taking into consideration asset allocation, reviewing historical returns on the type of assets held and current economic factors. Based on the Company’s anticipation of future experience under the defined benefit pension plan, the mortality tables used to determine future benefit obligations under the plan were updated as of December 31, 2021 to the sex-distinct Pri-2012 Mortality Tables for employees, healthy annuitants and contingent survivors, adjusted for mortality improvements using Scale MP-2021 mortality improvement scale on a generational basis. The appropriateness of the assumptions are reviewed annually. Plan Assets The investment objective for the defined benefit pension plan is to achieve an average annual total return over a five-year period equal to the assumed rate of return used in the actuarial calculations. At a minimum performance level, the portfolio should earn the return obtainable on high quality intermediate-term bonds. The Company’s perspective regarding portfolio assets combines both preservation of capital and moderate risk-taking. Asset allocation favors fixed income securities, with a target allocation of approximately 60% equity securities and 40% fixed income securities and money market funds. Due to the volatility in the market, the target allocation is not always desirable and asset allocations will fluctuate between acceptable ranges. Prohibited transactions include purchase of securities on margin, uncovered call options, and short sale transactions. The fair values of the Company’s defined benefit pension plan assets at December 31, 2021 by asset category are as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Quoted Prices ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ in Active ​ Significant ​ Significant ​ ​ ​ ​ Markets for ​ Observable ​ Unobservable ​ ​ ​ ​ Identical Assets ​ Inputs ​ Inputs ​ ​ Asset category (000’s omitted) Level 1 Level 2 Level 3 Total Cash equivalents ​ $ 19,605 ​ $ 0 ​ $ 0 ​ $ 19,605 Equity securities: ​ ​ ​ ​ ​ ​ ​ U.S. large-cap ​ 75,180 ​ 0 ​ 0 ​ 75,180 U.S mid/small cap ​ 12,052 ​ 0 ​ 0 ​ 12,052 CBU common stock ​ 7,604 ​ 0 ​ 0 ​ 7,604 International ​ 73,891 ​ 0 ​ 0 ​ 73,891 Other ​ 1,091 ​ 0 ​ 0 ​ 1,091 ​ ​ 169,818 ​ 0 ​ 0 ​ 169,818 ​ ​ ​ ​ ​ ​ ​ ​ Fixed income securities: ​ ​ ​ ​ ​ ​ ​ Government securities ​ 19,988 ​ 5,974 ​ 0 ​ 25,962 Investment grade bonds ​ 41,374 ​ 136 ​ 0 ​ 41,510 High yield (a) ​ 8,625 ​ 0 ​ 0 ​ 8,625 ​ ​ 69,987 ​ 6,110 ​ 0 ​ 76,097 ​ ​ ​ ​ ​ ​ ​ ​ Other investments (b) ​ 24,727 ​ 0 ​ 0 ​ 24,727 ​ ​ ​ ​ ​ ​ ​ ​ Total (c) ​ $ 284,137 ​ $ 6,110 ​ $ 0 ​ $ 290,247 ​ The fair values of the Company’s defined benefit pension plan assets at December 31, 2020 by asset category are as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Quoted Prices ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ in Active ​ Significant ​ Significant ​ ​ ​ ​ ​ Markets for ​ Observable ​ Unobservable ​ ​ ​ ​ ​ Identical Assets ​ Inputs ​ Inputs ​ ​ ​ Asset category (000’s omitted) Level 1 Level 2 Level 3 Total Cash equivalents ​ $ 68,137 ​ $ 0 ​ $ 0 ​ $ 68,137 Equity securities: ​ ​ ​ ​ ​ ​ ​ U.S. large-cap ​ 69,195 ​ 0 ​ 0 ​ 69,195 U.S mid/small cap ​ 17,338 ​ 0 ​ 0 ​ 17,338 CBU common stock ​ 7,701 ​ 0 ​ 0 ​ 7,701 International ​ 43,457 ​ 6,088 ​ 0 ​ 49,545 ​ ​ 137,691 ​ 6,088 ​ 0 ​ 143,779 ​ ​ ​ ​ ​ ​ ​ ​ Fixed income securities: ​ ​ ​ ​ ​ ​ ​ Government securities ​ 6,154 ​ 6,241 ​ 0 ​ 12,395 Investment grade bonds ​ 23,085 ​ 141 ​ 0 ​ 23,226 High yield (a) ​ 5,803 ​ 0 ​ 0 ​ 5,803 ​ ​ 35,042 ​ 6,382 ​ 0 ​ 41,424 ​ ​ ​ ​ ​ ​ ​ ​ Other investments (b) ​ 17,613 ​ 0 ​ 0 ​ 17,613 ​ ​ ​ ​ ​ ​ ​ ​ Total (c)(d) ​ $ 258,483 ​ $ 12,470 ​ $ 0 ​ $ 270,953 ​ (a) This category is exchange-traded funds representing a diversified index of high yield corporate bonds. (b) This category is comprised of exchange-traded funds and mutual funds holding non-traditional investment classes including private equity funds and alternative exchange funds. (c) Excludes dividends and interest receivable totaling $0.4 million and $0.2 million at December 31, 2021 and 2020, respectively. (d) Excludes certain investments that were measured at net asset value per share (or its equivalents) totaling $1.4 million at December 31, 2020. ​ The valuation techniques used to measure fair value for the items in the table above are as follows: ● Money market funds - Managed portfolios, including commercial paper and other fixed income securities issued by U.S. and foreign corporations, asset-backed commercial paper, U.S. government securities, obligations of foreign governments and U.S. and foreign banks, which are valued at the closing price reported on the market on which the underlying securities are traded. ● Equity securities and other investments – Mutual funds, equity securities and common stock of the Company which are valued at the quoted market price of shares held at year-end. ● Fixed income securities - U.S. Treasuries, municipal bonds and notes, government sponsored entities, and corporate debt valued at the closing price reported on the active market on which the individual securities are traded or for municipal bonds and notes based on quoted prices for similar assets in the active market. The Company makes contributions to its funded qualified pension plan as required by government regulation or as deemed appropriate by management after considering the fair value of plan assets, expected return on such assets, and the value of the accumulated benefit obligation. The Company made a $3.5 million contribution to the Steuben Trust Company Pension Plan in 2020. The Company made a $2.9 million and $3.9 million contribution to its defined benefit pension plan in 2021 and 2020, respectively. The Company funds the payment of benefit obligations for the supplemental pension and post-retirement plans because such plans do not hold assets for investment. 401(k) Employee Stock Ownership Plan The Company has a 401(k) Employee Stock Ownership Plan in which employees can contribute from 1% to 90% of eligible compensation, with the first 3% being eligible for a 100% matching contribution in the form of Company common stock and the next 3% being eligible for a 50% matching contributions in the form of Company common stock. The expense recognized under this plan for the years ended December 31, 2021, 2020 and 2019 was $6.9 million, $6.3 million, and $6.1 million, respectively. Effective January 1, 2010, the defined benefit pension plan was modified to a new plan design that includes an interest credit contribution to be made to the 401(k) plan. The expense recognized for this interest credit contribution for the years ended December 31, 2021, 2020, and 2019 was $1.1 million, $0.9 million, and $1.1 million, respectively. The Company acquired The National Union Bank of Kinderhook 401(k) Savings Plan with the Kinderhook acquisition and The Steuben Trust Company 401(k) Plan with the Steuben acquisition. Effective November 9, 2020 and January 1, 2021, The National Union Bank of Kinderhook 401(k) Savings Plan and The Steuben Trust Company 401(k) Plan were merged into and became part of the Community Bank System, Inc. 401(k) Employee Stock Ownership Plan, respectively. Other Deferred Compensation Arrangements In addition to the supplemental pension plans for certain executives, the Company has nonqualified deferred compensation arrangements for several former directors, officers and key employees. All benefits provided under these plans are unfunded and payments to plan participants are made by the Company. At December 31, 2021 and 2020, the Company has recorded a liability of $5.1 million and $5.4 million, respectively. The expense recognized under these plans for the years ended December 31, 2021, 2020, and 2019 was approximately $0.2 million, $0.4 million, and $0.2 million, respectively. Deferred Compensation Plans for Directors Directors of the Company may defer all or a portion of their director fees under the Deferred Compensation Plan for Directors. Under this plan, there is a separate account for each participating director which is credited with the amount of shares that could have been purchased with the director’s fees as well as any dividends on such shares. On the distribution date, the director will receive common stock equal to the accumulated share balance in their account. As of December 31, 2021 and 2020, there were 137,945 and 141,655 shares credited to the participants’ accounts, for which a liability of $5.1 million and $4.8 million was accrued, respectively. The expense recognized under the plan for the years ended December 31, 2021, 2020 and 2019, was $0.2 million, $0.2 million, and $0.2 million, respectively. The Company acquired deferred compensation plans for certain non-employee directors and trustees of Merchants. Under the terms of these acquired deferred compensation plans, participating directors could elect to have all, or a specified percentage, of their Merchants director’s fees for a given year paid in the form of cash or deferred in the form of restricted shares of Merchants’ common stock. Directors who elected to have their compensation deferred were credited with a number of shares of Merchants’ common stock equal in value to the amount of fees deferred. These shares were converted to shares of Company stock in connection with the acquisition and are held in a rabbi trust. The shares held in the rabbi trust are considered outstanding for purposes of computing earnings per share. The participating director may not sell, transfer or otherwise dispose of these shares prior to distribution. With respect to shares of common stock issued or otherwise transferred to a participating director, the participating director has the right to receive dividends or other distributions thereon.

STOCK-BASED COMPENSATION PLANS

STOCK-BASED COMPENSATION PLANS	12 Months Ended
	Dec. 31, 2021
STOCK-BASED COMPENSATION PLANS
STOCK-BASED COMPENSATION PLANS	NOTE L: STOCK-BASED COMPENSATION PLANS The Company has a long-term incentive program for directors, officers and employees. Under this program, the Company initially authorized four Activity in this long-term incentive program is as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ Stock Options ​ ​ ​ ​ Weighted- ​ ​ ​ ​ average Exercise ​ Outstanding Price of Shares Outstanding at December 31, 2019 1,502,994 ​ $ 42.82 Granted 254,496 ​ 51.68 Exercised (197,564) ​ 32.65 Forfeited (17,667) ​ 50.97 Outstanding at December 31, 2020 1,542,259 ​ 45.49 Granted 168,976 ​ 79.68 Exercised (310,423) ​ 40.17 Forfeited (8,107) ​ 61.56 Outstanding at December 31, 2021 1,392,705 ​ 50.73 Exercisable at December 31, 2021 879,074 ​ $ 43.84 ​ The following table summarizes the information about stock options outstanding under the Company’s stock option plan at December 31, 2021: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Options outstanding ​ Options exercisable ​ ​ ​ ​ Weighted- ​ Weighted- ​ ​ ​ Weighted- ​ ​ ​ ​ average ​ average ​ ​ ​ average ​ ​ ​ ​ Exercise ​ Remaining ​ ​ ​ Exercise Range of Exercise Price Shares Price Life (years) Shares Price $0.00 – $29.00 57,354 ​ $ 24.78 3.55 57,354 ​ $ 24.78 $29.01 – $30.00 58,276 ​ 29.79 1.21 58,276 ​ 29.79 $30.01 – $40.00 403,901 ​ 37.07 3.46 403,901 ​ 37.07 $40.01 – $60.00 706,389 ​ 55.54 6.91 352,515 ​ 56.30 $60.01 – $80.00 166,785 ​ 79.68 9.22 7,028 ​ 79.66 TOTAL 1,392,705 ​ $ 50.73 5.81 879,074 ​ $ 43.84 ​ The weighted-average remaining contractual term of outstanding and exercisable stock options at December 31, 2021 is 5.81 years and 4.56 years, respectively. The aggregate intrinsic value of outstanding and exercisable stock options at December 31, 2021 is $33.9 million and $27.0 million, respectively. The Company recognized stock-based compensation expense related to non-qualified stock options of $2.6 million, $2.7 million and $2.2 million for the years ended December 31, 2021, 2020 and 2019, respectively. A related income tax benefit was recognized of $0.6 million, $0.7 million and $0.5 million for the 2021, 2020 and 2019 years, respectively. Compensation expense related to restricted stock vesting recognized in the income statement for 2021, 2020 and 2019 was approximately $3.3 million, $3.3 million and $2.8 million, respectively. Management estimated the fair value of options granted using the Black-Scholes option-pricing model. This model was originally developed to estimate the fair value of exchange-traded equity options, which (unlike employee stock options) have no vesting period or transferability restrictions. As a result, the Black-Scholes model is not necessarily a precise indicator of the value of an option, but it is commonly used for this purpose. The Black-Scholes model requires several assumptions, which management developed based on historical trends and current market observations. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2021 2020 2019 Weighted-average Fair Value of Options Granted ​ $ 18.43 ​ $ 10.86 ​ $ 14.16 ​ Assumptions: ​ ​ ​ ​ ​ Weighted-average expected life (in years) ​ 6.50 ​ 6.50 ​ 6.50 ​ Future dividend yield ​ 2.48 % 2.57 % 2.73 % Share price volatility ​ 30.09 % 29.29 % 29.31 % Weighted-average risk-free interest rate ​ 1.28 % 0.67 % 2.44 % ​ Unrecognized stock-based compensation expense related to non-vested stock options totaled $5.5 million at December 31, 2021. The weighted-average period over which this unrecognized expense would be recognized is 3.3 years. The total fair value of stock options vested during 2021, 2020, and 2019 were $2.5 million, $2.5 million and $2.4 million, respectively. During the 12 months ended December 31, 2021 and 2020, proceeds from stock option exercises totaled $14.2 million and $7.5 million, respectively, and the related tax benefits from exercise were approximately $1.8 million and $1.2 million, respectively. During the twelve months ended December 31, 2021 and 2020, approximately 0.3 million and 0.2 million shares, respectively, were issued in connection with stock option exercises each year. The total intrinsic value of options exercised during 2021, 2020 and 2019 were $10.3 million, $6.6 million and $11.6 million, respectively. A summary of the status of the Company’s unvested restricted stock awards as of December 31, 2021, and changes during the twelve months ended December 31, 2021 and 2020, is presented below: ​ ​ ​ ​ ​ ​ ​ ​ ​ Restricted ​ Weighted-average ​ Shares grant date fair value Unvested at December 31, 2019 196,788 ​ $ 45.58 Awards 52,132 ​ 51.64 Forfeitures (12,884) ​ 37.14 Vestings (59,628) ​ 47.80 Unvested at December 31, 2020 176,408 ​ 47.24 Awards 51,456 ​ 79.51 Forfeitures (2,619) ​ 54.15 Vestings (47,977) ​ 52.84 Unvested at December 31, 2021 177,268 ​ $ 54.98 ​ Unrecognized stock-based compensation expense related to unvested restricted stock totaled $7.1 million at December 31, 2021, which will be recognized as expense over the next five years. The weighted-average period over which this unrecognized expense would be recognized is 3.7 years. The total fair value of restricted stock vested during 2021, 2020, and 2019 were $2.5 million, $2.9 million and $3.8 million, respectively.

EARNINGS PER SHARE

EARNINGS PER SHARE	12 Months Ended
	Dec. 31, 2021
EARNINGS PER SHARE
EARNINGS PER SHARE	NOTE M: 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 December 31, 2021. 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 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 0.1 million, 0.6 million and 0.5 million weighted-average anti-dilutive stock options outstanding at December 31, 2021, 2020 and 2019, respectively, which were not included in the computation below. The following is a reconciliation of basic to diluted earnings per share for the years ended December 31, 2021, 2020 and 2019. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (000’s omitted, except per share data) 2021 2020 2019 Net income ​ $ 189,694 ​ $ 164,676 ​ $ 169,063 Income attributable to unvested stock-based compensation awards ​ (445) ​ (514) ​ (400) Income available to common shareholders ​ $ 189,249 ​ $ 164,162 ​ $ 168,663 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted-average common shares outstanding – basic ​ 53,977 ​ 52,969 ​ 51,732 Basic earnings per share ​ $ 3.51 ​ $ 3.10 ​ $ 3.26 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net income ​ $ 189,694 ​ $ 164,676 ​ $ 169,063 Income attributable to unvested stock-based compensation awards ​ (445) ​ (514) ​ (400) Income available to common shareholders ​ $ 189,249 ​ $ 164,162 ​ $ 168,663 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted-average common shares outstanding ​ 53,977 ​ 52,969 ​ 51,732 Assumed exercise of stock options ​ 423 ​ 352 ​ 516 Weighted-average common shares outstanding – diluted ​ 54,400 ​ 53,321 ​ 52,248 Diluted earnings per share ​ $ 3.48 ​ $ 3.08 ​ $ 3.23 Cash dividends declared per share ​ $ 1.70 ​ $ 1.66 ​ $ 1.58 ​ Stock Repurchase Program At its December 2020 meeting, the Board approved a stock repurchase program authorizing the repurchase, at the discretion of senior management, of up to 2,680,000 shares of the Company’s common stock, in accordance with securities and banking laws and regulations, during the twelve-month period starting January 1, 2021. There were 67,500 shares repurchased pursuant to the 2021 stock repurchase program in the fourth quarter of 2021. At its December 2021 meeting, the Board approved a new stock repurchase program authorizing the repurchase, at the discretion of senior management, of up to 2,697,000 shares of the Company’s common stock, in accordance with securities and banking laws and regulations, during the twelve-month period starting January 1, 2022. 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.

COMMITMENTS, CONTINGENT LIABILI

COMMITMENTS, CONTINGENT LIABILITIES AND RESTRICTIONS	12 Months Ended
	Dec. 31, 2021
COMMITMENTS, CONTINGENT LIABILITIES AND RESTRICTIONS
COMMITMENTS, CONTINGENT LIABILITIES AND RESTRICTIONS	NOTE N: 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 at December 31: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (000’s omitted) 2021 2020 Commitments to extend credit ​ $ 1,443,879 ​ $ 1,313,568 Standby letters of credit ​ 42,684 ​ 39,213 Total ​ $ 1,486,563 ​ $ 1,352,781 ​ The Bank has unused lines of credit of $25.0 million at December 31, 2021. The Bank has unused borrowing capacity of approximately $1.71 billion through collateralized transactions with the FHLB and $247.7 million through collateralized transactions with the Federal Reserve. The Company is typically required to maintain a reserve balance, as established by the FRB. Effective on March 26, 2020, the FRB reduced this cash reserve requirement to zero percent to help support lending to households and businesses as a result of the impacts of the COVID-19 pandemic. As a result, the Company had no required reserve as of December 31, 2021 and 2020. 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 December 31, 2021, 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 believed to be between $0 and $1 million in the aggregate. This estimated range is based on information currently available to the Company and involves elements of judgment and significant uncertainties. The Company does not believe that the outcome of pending or threatened 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. The Company recorded $3.0 million in litigation accrual in 2020 related to a settlement of a purported class action lawsuit regarding the Bank’s deposit account terms and overdraft disclosures. The Company executed a settlement agreement with respect to the lawsuit in the fourth quarter of 2020 providing for a release of all claims asserted by class members in the action, and the Company does not anticipate that additional amounts will be accrued for this matter in future periods. Notice of the settlement terms was provided to all class members and no objections to the settlement were received prior to expiration of the notice period. The hearing for final Court approval of the settlement took place on August 25, 2021 and the settlement was approved for $2.9 million which was paid in the third quarter of 2021, resulting in a $0.1 million adjustment to the Company’s litigation accrual.

LEASES

LEASES	12 Months Ended
	Dec. 31, 2021
LEASES
LEASES	NOTE O: LEASES The Company has operating leases for certain offices and certain equipment. These leases have remaining terms that range from less than one year to 13 years. Options to extend the leases range from a single extension option of one year to multiple extension options for up to 40 years. Certain agreements include an option to terminate the lease within one year. The components of lease expense are as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (000’s omitted) 2021 ​ 2020 ​ 2019 Operating lease cost ​ $ 8,397 ​ $ 9,000 ​ $ 8,724 Variable lease cost ​ 50 ​ ​ 53 ​ ​ 18 Short-term lease cost (1) ​ 148 ​ ​ 369 ​ ​ 240 Total lease cost ​ $ 8,595 ​ $ 9,422 ​ $ 8,982 ​ (1) Short-term lease cost includes the cost of leases with terms of twelve months or less, excluding leases with terms of one month or less. Supplemental cash flow information related to leases is as follows: ​ ​ ​ ​ ​ ​ ​ ​ (000’s omitted) 2021 2020 Cash paid for amounts included in the measurement of lease liabilities: ​ ​ ​ ​ Operating cash outflows for operating leases ​ $ 8,203 ​ $ 8,478 ​ ​ ​ ​ ​ ​ ​ Right-of-use assets obtained in exchange for lease obligations: ​ ​ ​ ​ ​ Operating leases ​ 5,344 ​ ​ 3,519 ​ Supplemental balance sheet information related to leases is as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ (000’s omitted, except lease term and discount rate) 2021 2020 ​ Operating leases ​ ​ ​ ​ ​ Operating lease right-of-use assets ​ $ 31,754 ​ $ 34,908 ​ ​ ​ ​ ​ ​ ​ ​ ​ Operating lease liabilities ​ 32,833 ​ ​ 35,857 ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted average remaining lease term ​ ​ ​ ​ ​ ​ Operating leases ​ 5.4 years ​ ​ 6.1 years ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted average discount rate ​ ​ ​ ​ ​ ​ Operating leases ​ 2.62 % ​ 2.82 % ​ Maturities of lease liabilities as of December 31, 2021 are as follows: ​ ​ ​ ​ ​ (000’s omitted) Operating Leases 2022 ​ $ 8,729 2023 ​ 7,640 2024 ​ 5,920 2025 ​ 4,401 2026 ​ 3,062 Thereafter ​ 5,846 Total lease payments ​ 35,598 Less imputed interest ​ (2,765) Total ​ $ 32,833 ​ Maturities of lease liabilities as of December 31, 2020 are as follows: ​ ​ ​ ​ ​ (000’s omitted) Operating Leases 2021 ​ $ 8,697 2022 ​ 7,505 2023 ​ 6,336 2024 ​ 4,973 2025 ​ 3,688 Thereafter ​ 8,222 Total lease payments ​ 39,421 Less imputed interest ​ (3,564) Total ​ $ 35,857 ​ Included in the Company’s operating leases are related party leases where BPAS APS and OneGroup, subsidiaries of the Company, lease office space from 706 North Clinton, LLC (“706 North Clinton”), an entity the Company holds a 50% membership interest in through its subsidiary OPFC II. As of December 31, 2021, the operating lease right-of-use assets and operating lease liabilities associated with these related party leases total $4.0 million and $4.1 million, respectively. As of December 31, 2020, the operating lease right-of-use assets and operating lease liabilities associated with these related party leases total $4.5 million and $4.5 million, respectively. As of December 31, 2021, the weighted average remaining lease term and weighted average discount rate for the Company’s related party leases are 8.0 years and 3.68 %, respectively. As of December 31, 2020, the weighted average remaining lease term and weighted average discount rate for the Company’s related party leases are 9.0 years and 3.68%, respectively. The maturities of the Company’s related party lease liabilities as of December 31, 2021 are as follows: ​ ​ ​ ​ ​ (000’s omitted) 706 North Clinton, LLC 2022 ​ $ 591 2023 ​ 591 2024 ​ 591 2025 ​ 605 2026 ​ 614 Thereafter ​ 1,727 Total lease payments ​ 4,719 Less imputed interest ​ (633) Total ​ $ 4,086 ​ The maturities of the Company’s related party lease liabilities as of December 31, 2020 are as follows: ​ ​ ​ ​ ​ (000’s omitted) ​ 706 North Clinton, LLC 2021 $ 591 2022 ​ 591 2023 ​ ​ 591 2024 ​ ​ 591 2025 ​ 605 Thereafter ​ 2,341 Total lease payments ​ 5,310 Less imputed interest ​ (791) Total ​ $ 4,519 ​ As of December 31, 2021, the Company has an immaterial amount of additional operating leases for offices and equipment that have not yet commenced.

REGULATORY MATTERS

REGULATORY MATTERS	12 Months Ended
	Dec. 31, 2021
REGULATORY MATTERS
REGULATORY MATTERS	NOTE P: REGULATORY MATTERS The Company and the Bank are subject to various regulatory capital requirements administered by federal banking agencies. Failure to meet minimum capital requirements can initiate certain mandatory and possibly additional discretionary actions by regulators that, if undertaken, could have a direct material effect on the Company’s financial statements. Under capital adequacy guidelines and the regulatory framework for prompt corrective action, the Company and the Bank must meet specific capital guidelines that involve quantitative measures of the Company’s and the Bank’s assets, liabilities, and certain off-balance sheet items as calculated under regulatory accounting practices. The Company’s and the Bank's capital amounts and classification are also subject to qualitative judgments by the regulators about components, risk weightings, and other factors. Management believes, as of December 31, 2021, that the Company and Bank meet all applicable capital adequacy requirements. The Company and the Bank are required to maintain a “capital conservation buffer,” composed entirely of common equity Tier 1 capital, in addition to minimum risk-based capital ratios. The required capital conservation buffer is 2.50% for both 2021 and 2020. Therefore, to satisfy both the minimum risk-based capital ratios and the capital conservation buffer in 2021 and 2020, the Company and the Bank must maintain: (i) Common equity Tier 1 capital to total risk-weighted assets of at least 7.0%, (ii) Tier 1 capital to total risk-weighted assets of at least 8.5%, and (iii) Total capital (Tier 1 capital plus Tier 2 capital) to total risk-weighted assets of at least 10.5%. As of December 31, 2021 and 2020, the amounts, ratios and requirements for the Company are presented below. As of December 31, 2021, the OCC categorized the Company and Bank as “well capitalized” under the regulatory framework for prompt corrective action. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For capital adequacy ​ To be well-capitalized ​ ​ ​ ​ ​ ​ ​ For capital adequacy ​ purposes plus Capital ​ under prompt ​ ​ Actual ​ purposes ​ Conservation Buffer ​ corrective action (000’s omitted) Amount Ratio Amount Ratio Amount Ratio Amount Ratio Community Bank System, Inc.: ​ ​ ​ ​ ​ 2021 ​ ​ ​ ​ ​ Tier 1 Leverage ratio ​ $ 1,331,368 9.09 % $ 585,594 4.00 % ​ ​ ​ ​ $ 731,993 5.00 % Tier 1 risk-based capital ​ 1,331,368 18.60 % 429,559 6.00 % $ 608,542 8.50 % ​ 572,746 8.00 % Total risk-based capital ​ 1,380,458 19.28 % 572,746 8.00 % 751,729 10.50 % ​ 715,932 10.00 % Common equity tier 1 capital ​ 1,331,259 18.60 % 322,169 4.50 % 501,152 7.00 % ​ 465,356 6.50 % 2020 ​ ​ ​ ​ ​ ​ ​ ​ ​ Tier 1 Leverage ratio ​ $ 1,314,864 10.16 % $ 517,736 4.00 % ​ ​ ​ ​ $ 647,169 5.00 % Tier 1 risk-based capital ​ 1,314,864 18.99 % 415,472 6.00 % $ 588,585 8.50 % ​ 553,962 8.00 % Total risk-based capital ​ 1,375,704 19.87 % 553,962 8.00 % 727,075 10.50 % ​ 692,453 10.00 % Common equity tier 1 capital ​ 1,239,754 17.90 % 311,604 4.50 % 484,717 7.00 % ​ 450,094 6.50 % ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Community Bank, N.A.: ​ ​ ​ ​ ​ 2021 ​ ​ ​ ​ ​ Tier 1 Leverage ratio ​ $ 1,058,091 7.26 % $ 582,631 4.00 % ​ ​ ​ ​ $ 728,289 5.00 % Tier 1 risk-based capital ​ 1,058,091 14.92 % 425,393 6.00 % $ 602,640 8.50 % ​ 567,190 8.00 % Total risk-based capital ​ 1,107,181 15.62 % 567,190 8.00 % 744,437 10.50 % ​ 708,988 10.00 % Common equity tier 1 capital ​ 1,057,982 14.92 % 319,045 4.50 % 496,292 7.00 % ​ 460,842 6.50 % 2020 ​ ​ ​ ​ ​ ​ ​ ​ Tier 1 Leverage ratio ​ $ 1,028,285 7.98 % $ 515,552 4.00 % ​ ​ ​ ​ $ 644,440 5.00 % Tier 1 risk-based capital ​ 1,028,285 14.98 % 411,880 6.00 % $ 583,497 8.50 % ​ 549,174 8.00 % Total risk-based capital ​ 1,089,125 15.87 % 549,174 8.00 % 720,791 10.50 % ​ 686,467 10.00 % Common equity tier 1 capital ​ 1,028,175 14.98 % 308,910 4.50 % 480,527 7.00 % ​ 446,204 6.50 % ​

PARENT COMPANY STATEMENTS

PARENT COMPANY STATEMENTS	12 Months Ended
	Dec. 31, 2021
PARENT COMPANY STATEMENTS
PARENT COMPANY STATEMENTS	NOTE Q: PARENT COMPANY STATEMENTS The condensed statements of condition of the parent company, Community Bank System, Inc., at December 31 are as follows: ​ ​ ​ ​ ​ ​ ​ ​ (000's omitted) 2021 2020 Assets: ​ ​ Cash and cash equivalents ​ $ 154,374 ​ $ 196,021 Investment securities ​ 8,679 ​ 6,043 Investment in and advances to: ​ ​ ​ Bank subsidiary ​ 1,721,520 ​ 1,802,150 Non-bank subsidiaries ​ 232,096 ​ 196,090 Other assets ​ 18,462 ​ 15,290 Total assets ​ $ 2,135,131 ​ $ 2,215,594 ​ ​ ​ ​ ​ ​ ​ Liabilities and shareholders' equity: ​ ​ ​ Accrued interest and other liabilities ​ $ 31,047 ​ $ 30,864 Borrowings ​ 3,277 ​ 80,623 Shareholders' equity ​ 2,100,807 ​ 2,104,107 Total liabilities and shareholders' equity ​ $ 2,135,131 ​ $ 2,215,594 ​ The condensed statements of income of the parent company for the years ended December 31 is as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (000's omitted) 2021 2020 2019 Revenues: ​ ​ ​ Dividends from subsidiaries: ​ ​ ​ Bank subsidiary ​ $ 125,000 ​ $ 105,000 ​ $ 115,000 Non-bank subsidiaries ​ 14,000 ​ 13,500 ​ 27,600 Interest and dividends on investments ​ 245 ​ 168 ​ 134 Total revenues ​ 139,245 ​ 118,668 ​ 142,734 Expenses: ​ ​ ​ ​ ​ ​ Interest on borrowings ​ 446 ​ 2,546 ​ 4,244 Acquisition expenses ​ 0 ​ 450 ​ 1,248 Gain on debt extinguishment ​ 0 ​ (421) ​ 0 Other expenses ​ 5,717 ​ 4,945 ​ 477 Total expenses ​ 6,163 ​ 7,520 ​ 5,969 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Income before tax benefit and equity in undistributed net income of subsidiaries ​ 133,082 ​ 111,148 ​ 136,765 Income tax benefit ​ 3,964 ​ 3,739 ​ 4,545 Income before equity in undistributed net income of subsidiaries ​ 137,046 ​ 114,887 ​ 141,310 Equity in undistributed net income of subsidiaries ​ 52,648 ​ 49,789 ​ 27,753 Net income ​ $ 189,694 ​ $ 164,676 ​ $ 169,063 Other comprehensive (loss) income, net of tax: ​ ​ ​ ​ ​ ​ Changes in other comprehensive income (loss) related to pension and other post retirement obligations ​ 13,403 ​ 6,009 ​ (2,045) Changes in other comprehensive (loss) income related to unrealized (losses) gains on available-for-sale securities ​ (126,107) ​ 66,294 ​ 37,124 Other comprehensive (loss) income ​ (112,704) ​ 72,303 ​ 35,079 Comprehensive income ​ $ 76,990 ​ $ 236,979 ​ $ 204,142 ​ The statements of cash flows of the parent company for the years ended December 31 is as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (000's omitted) 2021 2020 2019 Operating activities: ​ ​ ​ Net income ​ $ 189,694 ​ $ 164,676 ​ $ 169,063 Adjustments to reconcile net income to net cash provided by operating activities ​ ​ ​ ​ ​ ​ Equity in undistributed net income of subsidiaries ​ (52,648) ​ (49,789) ​ (27,753) Net change in other assets and other liabilities ​ (3,050) ​ 1,740 ​ 86 Net cash provided by operating activities ​ 133,996 ​ 116,627 ​ 141,396 Investing activities: ​ ​ ​ ​ ​ ​ Purchases of investment securities ​ ​ (5,173) ​ ​ (3,000) ​ ​ 0 Cash paid for acquisitions, net of cash acquired of $0, $448, and $1,328, respectively ​ 0 ​ (20,892) ​ (92,056) (Capital contributions to)/Return of capital from ​ (12,918) ​ 2 ​ 100,680 Net cash (used in)/provided by investing activities ​ (18,091) ​ (23,890) ​ 8,624 Financing activities: ​ ​ ​ ​ ​ ​ Repayment of advances from subsidiaries ​ (482) ​ (482) ​ (1,652) Repayment of borrowings ​ (77,320) ​ (12,062) ​ (22,681) Issuance of common stock ​ 16,155 ​ 22,211 ​ 12,200 Purchase of treasury stock ​ (5,106) ​ (271) ​ (286) Sale of treasury stock ​ 0 ​ 85 ​ 6,884 Increase in deferred compensation arrangements ​ 252 ​ 271 ​ 286 Cash dividends paid ​ (91,051) ​ (87,131) ​ (80,241) Net cash used in financing activities ​ (157,552) ​ (77,379) ​ (85,490) Change in cash and cash equivalents ​ (41,647) ​ 15,358 ​ 64,530 Cash and cash equivalents at beginning of year ​ 196,021 ​ 180,663 ​ 116,133 Cash and cash equivalents at end of year ​ $ 154,374 ​ $ 196,021 ​ $ 180,663 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Supplemental disclosures of cash flow information: ​ ​ ​ ​ Cash paid for interest ​ $ 560 ​ $ 2,555 ​ $ 4,306 Supplemental disclosures of noncash financing activities: ​ ​ ​ Dividends declared and unpaid ​ $ 23,235 ​ $ 22,695 ​ $ 21,342 Advances from subsidiaries ​ 482 ​ 932 ​ 1,691 Common stock issued for acquisition ​ 0 ​ 76,942 ​ 0 ​

FAIR VALUE

FAIR VALUE	12 Months Ended
	Dec. 31, 2021
FAIR VALUE
FAIR VALUE	NOTE R: FAIR VALUE Accounting standards allow entities an irrevocable option to measure certain financial assets and financial liabilities at fair value. Unrealized gains and losses on items for which the fair value option has been elected are reported in earnings. The Company has elected to value mortgage 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. 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: ● ● ● 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. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2021 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total Fair (000’s omitted) Level 1 Level 2 Level 3 Value Available-for-sale investment securities: ​ ​ ​ ​ U.S. Treasury and agency securities ​ $ 3,900,924 ​ $ 97,640 ​ $ 0 ​ $ 3,998,564 Obligations of state and political subdivisions ​ 0 ​ 430,289 ​ 0 ​ 430,289 Government agency mortgage-backed securities ​ 0 ​ 477,056 ​ 0 ​ 477,056 Corporate debt securities ​ 0 ​ 7,962 ​ 0 ​ 7,962 Government agency collateralized mortgage obligations ​ 0 ​ 20,339 ​ 0 ​ 20,339 Total available-for-sale investment securities ​ 3,900,924 ​ 1,033,286 ​ 0 ​ 4,934,210 Equity securities ​ 463 ​ 0 ​ 0 ​ 463 Commitments to originate real estate loans for sale ​ ​ 0 ​ ​ 0 ​ ​ 51 ​ ​ 51 Forward sales commitments ​ ​ 0 ​ ​ 32 ​ ​ 0 ​ ​ 32 Interest rate swap agreements asset ​ 0 ​ 296 ​ 0 ​ 296 Interest rate swap agreements liability ​ 0 ​ (3) ​ 0 ​ (3) Total ​ $ 3,901,387 ​ $ 1,033,611 ​ $ 51 ​ $ 4,935,049 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2020 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total Fair (000’s omitted) Level 1 Level 2 Level 3 Value Available-for-sale investment securities: ​ ​ ​ ​ U.S. Treasury and agency securities ​ $ 2,359,912 ​ $ 141,470 ​ $ 0 ​ $ 2,501,382 Obligations of state and political subdivisions ​ 0 ​ 475,660 ​ 0 ​ 475,660 Government agency mortgage-backed securities ​ 0 ​ 522,638 ​ 0 ​ 522,638 Corporate debt securities ​ 0 ​ 4,635 ​ 0 ​ 4,635 Government agency collateralized mortgage obligations ​ 0 ​ 43,577 ​ 0 ​ 43,577 Total available-for-sale investment securities ​ 2,359,912 ​ 1,187,980 ​ 0 ​ 3,547,892 Equity securities ​ 445 ​ 0 ​ 0 ​ 445 Mortgage loans held for sale ​ 0 ​ 1,622 ​ 0 ​ 1,622 Commitments to originate real estate loans for sale ​ ​ 0 ​ ​ 0 ​ ​ 14 ​ ​ 14 Forward sales commitments ​ ​ 0 ​ ​ 2 ​ ​ 0 ​ ​ 2 Interest rate swap agreements asset ​ 0 ​ 1,572 ​ 0 ​ 1,572 Interest rate swap agreements liability ​ 0 ​ (1,074) ​ ​ 0 ​ (1,074) Total ​ $ 2,360,357 ​ $ 1,190,102 ​ $ 14 ​ $ 3,550,473 ​ 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 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 marketable 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 C 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 December 31, 2021. The unpaid principal value of mortgage loans held for sale was approximately $1.6 million at December 31, 2020. The unrealized gain on mortgage loans held for sale was recognized in mortgage banking 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 statements 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 statements 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 swap agreements – 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. Assets and liabilities measured on a non-recurring basis: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2021 ​ December 31, 2020 ​ ​ ​ ​ ​ ​ ​ ​ Total Fair ​ ​ ​ ​ ​ ​ Total Fair (000's omitted) ​ Level 1 ​ Level 2 ​ Level 3 ​ Value ​ Level 1 ​ Level 2 ​ Level 3 ​ Value Individually assessed loans ​ $ 0 ​ $ 0 ​ $ 1,820 $ 1,820 ​ $ 0 ​ $ 0 ​ $ 25,063 $ 25,063 Other real estate owned ​ 0 ​ 0 ​ 718 718 ​ 0 ​ 0 ​ 883 883 Mortgage servicing rights ​ 0 ​ 0 ​ 810 810 ​ 0 ​ 0 ​ 682 682 Contingent consideration ​ ​ 0 ​ ​ 0 ​ ​ (3,100) ​ ​ (3,100) ​ ​ 0 ​ ​ 0 ​ ​ 0 ​ ​ 0 Total ​ $ 0 ​ $ 0 ​ $ 248 $ 248 ​ $ 0 ​ $ 0 ​ $ 26,628 $ 26,628 ​ 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 credit losses. Such amounts are generally based on the fair value of the underlying collateral supporting the loan and, as a result, the carrying value of the loan less the calculated valuation 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 estimated 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 31.8% to 42.3% at December 31, 2021, 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 was no The Company has recorded contingent consideration liabilities that arise from acquisition activity. The contingent consideration is recorded at fair value at the date of acquisition. The valuation of contingent consideration is calculated using an income approach method, which provides an estimation of the fair value of an asset or liability based on future cash flows over a discrete projection period, discounted to present value using an appropriate rate of return. The assumptions used in the valuation calculation are based on significant unobservable inputs, therefore such valuations classify as Level 3. The Company evaluates goodwill for impairment on an annual basis, or more often if events or circumstances indicate there may be impairment. The fair value of each reporting unit is compared to the carrying amount of that reporting unit in order to determine if impairment is indicated. If so, the implied fair value of the reporting unit’s goodwill is compared to its carrying amount and the impairment loss is measured by the excess of the carrying value of the goodwill over fair value of the goodwill. In such situations, the Company performs a discounted cash flow modeling technique that requires management to make estimates regarding the amount and timing of expected future cash flows of the assets and liabilities of the reporting unit that enable the Company to calculate the implied fair value of the goodwill. It also requires use of a discount rate that reflects the current return expectation of the market in relation to present risk-free interest rates, expected equity market premiums, peer volatility indicators and company-specific risk indicators. The Company did not recognize an impairment charge during 2021 or 2020. The significant unobservable inputs used in the determination of fair value of assets classified as Level 3 on a recurring or non-recurring basis as of December 31, 2021 are as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Significant Significant Unobservable ​ ​ ​ ​ ​ Valuation ​ Unobservable ​ Input Range (000’s omitted) ​ Fair Value ​ Technique ​ Inputs ​ (Weighted Average) Individually assessed loans ​ $ 1,820 Fair value of collateral Estimated cost of disposal/market adjustment ​ 9.0% - 43.1% (43.1%) ​ Other real estate owned ​ 718 Fair value of collateral Estimated cost of disposal/market adjustment ​ 31.8% - 42.3% (33.3%) ​ Commitments to originate real estate loans for sale ​ ​ 51 ​ Discounted cash flow ​ Embedded servicing value ​ ​ 1.0 % Mortgage servicing rights ​ 810 Discounted cash flow Weighted average constant prepayment rate ​ 6.4% - 15.2% (14.0%) ​ ​ ​ ​ ​ ​ ​ Weighted average discount rate ​ 2.3% - 2.7% (2.6%) ​ ​ ​ ​ ​ ​ ​ Adequate compensation ​ $ 7/loan ​ Contingent consideration ​ ​ (3,100) ​ Discounted cash flow ​ Discount rate ​ ​ 1.4% - 1.7% (1.5%) ​ ​ ​ ​ ​ ​ ​ ​ Probability adjusted level of retained revenue ​ ​ $3.0 million - $5.8 million ​ ​ The significant unobservable inputs used in the determination of fair value of assets classified as Level 3 on a recurring or non-recurring basis as of December 31, 2020 are as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Significant Significant Unobservable ​ ​ ​ ​ ​ Valuation ​ Unobservable ​ Input Range (000’s omitted) ​ Fair Value ​ Technique ​ Inputs ​ (Weighted Average) Individually assessed loans ​ $ 25,063 Fair value of collateral Estimated cost of disposal/market adjustment ​ 9.0% - 78.4% (52.7%) ​ Other real estate owned ​ 883 Fair value of collateral Estimated cost of disposal/market adjustment ​ 11.3% - 52.9% (34.0%) ​ Commitments to originate real estate loans for sale ​ ​ 14 ​ Discounted cash flow ​ Embedded servicing value ​ ​ 1.0 % Mortgage servicing rights ​ 682 Discounted cash flow Weighted average constant prepayment rate ​ 9.8% - 18.8% (17.6%) ​ ​ ​ ​ ​ ​ ​ Weighted average discount rate ​ 1.7% - 2.2% (2.1%) ​ ​ ​ ​ ​ ​ ​ Adequate compensation ​ $ 7/loan ​ ​ 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. 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 significant unobservable inputs used in the determination of the fair value of assets classified as Level 3 have an inherent measurement uncertainty that if changed could result in higher or lower fair value measurements of these assets as of the reporting date. The weighted average of the estimated cost of disposal/market adjustment for individually assessed loans was calculated by dividing the total of the book value of the collateral of the individually assessed loans classified as Level 3 by the total of the fair value of the collateral of the individually assessed loans classified as Level 3. The weighted average of the estimated cost of disposal/market adjustment for other real estate owned was calculated by dividing the total of the differences between the appraisal values of the real estate and the book values of the real estate divided by the totals of the appraisal values of the real estate. The weighted average of the constant prepayment rate for mortgage servicing rights was calculated by adding the constant prepayment rates used in each loan pool weighted by the balance in each loan pool. The weighted average of the discount rate for mortgage servicing rights was calculated by adding the discount rates used in each loan pool weighted by the balance in each loan pool. The weighted average of the discount rate for the contingent consideration was calculated by adding the discount rates used for the calculation of the fair value of each payment of contingent consideration, weighted by the amount of the payment as part of the total fair value of contingent consideration. The carrying amounts and estimated fair values of the Company’s other financial instruments that are not accounted for at fair value at December 31, 2021 and 2020 are as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2021 ​ December 31, 2020 ​ Carrying ​ Carrying ​ (000's omitted) ​ Value ​ Fair Value ​ Value ​ Fair Value Financial assets: ​ ​ ​ ​ Net loans ​ $ 7,323,770 ​ $ 7,523,024 ​ $ 7,355,083 ​ $ 7,655,044 Financial liabilities: ​ ​ ​ ​ ​ ​ ​ ​ Deposits ​ 12,911,168 ​ 12,911,197 ​ 11,224,974 ​ 11,239,628 Securities sold under agreement to repurchase, short-term ​ 324,720 ​ 324,720 ​ 284,008 ​ 284,008 Other Federal Home Loan Bank borrowings ​ 1,888 ​ 1,907 ​ 6,658 ​ 6,758 Subordinated notes payable ​ 3,277 ​ 3,277 ​ 3,303 ​ 3,303 Subordinated debt held by unconsolidated subsidiary trusts ​ 0 ​ 0 ​ 77,320 ​ 77,320 ​ 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 securities sold under agreement to repurchase, short-term, is the amount payable on demand at the reporting date. Fair values for long-term borrowings 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 values of long-term borrowings and subordinated debt held by unconsolidated subsidiary trusts, and their fair values, are 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	12 Months Ended
	Dec. 31, 2021
DERIVATIVE INSTRUMENTS
DERIVATIVE INSTRUMENTS	NOTE S: 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 December 31, 2021 and 2020. The effect of the changes to these derivatives for the years then ended was also immaterial. The Company acquired interest rate swaps in 2017 with notional amounts with certain commercial customers which totaled $0.5 million at December 31, 2021 and $14.4 million at December 31, 2020. 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 $0.5 million at December 31, 2021 and $14.4 million at December 31, 2020. At December 31, 2021, the weighted average receive rate of these interest rate swaps was 2.35%, the weighted average pay rate was 3.54% and the weighted average maturity was 1.3 years. At December 31, 2020, the weighted average receive rate of these interest rate swaps was 2.10%, the weighted average pay rate was 4.44% and the weighted average maturity was 5.2 years. 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 2017 with notional amounts totaling $5.3 million at December 31, 2021 and $5.7 million at December 31, 2020 that were designated as fair value hedges of certain fixed rate loans with municipalities which are recorded in loans in the consolidated statements of condition. At December 31, 2021, the weighted average receive rate of these interest rate swaps was 1.39%, the weighted average pay rate was 3.11% and the weighted average maturity was 11.5 years. At December 31, 2020, the weighted average receive rate of these interest rate swaps was 1.42%, the weighted average pay rate was 3.11% and the weighted average maturity was 12.5 years. The Company includes the gain or loss on the hedged items in interest and fees on loans, the same line item as the offsetting gain or loss on the related interest rate swaps. The effects of fair value accounting in the consolidated statements of income for the years ended December 31, 2021 and 2020 is immaterial. As of December 31, 2021 and 2020, the following amounts were recorded in the consolidated statement of condition related to cumulative basis adjustments for fair value hedges: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (000’s omitted) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Cumulative Amount of Fair Value Hedging Line Item in the Consolidated ​ Carrying Amount of the Hedged ​ Adjustment Included in the Carrying Statement of Condition in Which ​ Assets ​ Amount of the Hedged Assets the Hedged Item Is Included December 31, 2021 December 31, 2020 December 31, 2021 December 31, 2020 Loans ​ $ 5,400 ​ $ 5,675 ​ $ (293) ​ $ (498) ​ Fair values of derivative instruments as of December 31, 2021 are as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (000’s omitted) ​ December 31, 2021 ​ ​ ​ Derivative Assets ​ Derivative Liabilities ​ ​ ​ Consolidated Statement of ​ Fair ​ Consolidated Statement of Condition ​ Fair ​ ​ ​ Condition Location Value Location Value ​ Derivatives designated as hedging instruments under Subtopic 815-20 ​ ​ ​ ​ ​ ​ Interest rate swaps Other assets ​ $ 293 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Derivatives not designated as hedging instruments under Subtopic 815-20 ​ ​ ​ ​ ​ Interest rate swaps Other assets ​ 3 Accrued interest and other liabilities $ 3 ​ Commitments to originate real estate loans for sale ​ Other assets ​ ​ 51 ​ ​ ​ ​ ​ ​ Forward sales commitments ​ Other assets ​ ​ 32 ​ ​ ​ ​ ​ ​ Total derivatives ​ $ 379 $ 3 ​ ​ Fair values of derivative instruments as of December 31, 2020 are as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (000’s omitted) December 31, 2020 ​ ​ Derivative Assets ​ Derivative Liabilities ​ Consolidated Statement of ​ ​ Consolidated Statement of Condition ​ ​ ​ Condition Location Fair Value Location Fair Value Derivatives designated as hedging instruments under Subtopic 815-20 ​ ​ ​ Interest rate swaps ​ Other assets ​ $ 498 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Derivatives not designated as hedging instruments under Subtopic 815-20 ​ ​ ​ Interest rate swaps ​ Other assets ​ 1,074 Accrued interest and other liabilities ​ $ 1,074 Commitments to originate real estate loans for sale ​ ​ Other assets ​ ​ 14 ​ ​ ​ ​ ​ Forward sales commitments ​ ​ Other assets ​ ​ 2 ​ ​ ​ ​ ​ Total derivatives ​ ​ ​ ​ $ 1,588 ​ $ 1,074 ​ The Company assessed its counterparty risk at December 31, 2021 and 2020 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 R to these consolidated financial statements.

VARIABLE INTEREST ENTITIES

VARIABLE INTEREST ENTITIES	12 Months Ended
	Dec. 31, 2021
VARIABLE INTEREST ENTITIES
VARIABLE INTEREST ENTITIES	NOTE T: VARIABLE INTEREST ENTITIES The Company’s wholly-owned subsidiary CCT IV was a VIE for which the Company was not the primary beneficiary. Accordingly, the accounts of this entity were not included in the Company’s consolidated financial statements. On March 15, 2021, the Company exercised its right to redeem all of the CCT IV debentures and associated preferred securities. See further information regarding CCT IV in Note H: Borrowings. In connection with the Company’s acquisition of Oneida Financial Corp, the Company acquired OPFC II which holds a 50% membership interest in 706 North Clinton, an entity formed for the purpose of acquiring and rehabilitating real property. The real property held by 706 North Clinton is principally occupied by subsidiaries of the Company. The Company analyzed the operating agreement and capital structure of 706 North Clinton and determined that it was the primary beneficiary and therefore should consolidate 706 North Clinton in its financial statements. This conclusion was based on the determination that the Company has a de facto agency relationship because of the financing arrangement between the other member of 706 North Clinton and the Bank which provides OPFC II with both the power to direct the activities of 706 North Clinton and the obligation to absorb any losses of 706 North Clinton. The carrying amount of the assets and liabilities of 706 North Clinton and the classification of these assets and liabilities in the Company’s consolidated statements of condition at December 31 is as follows: ​ ​ ​ ​ ​ ​ ​ ​ (000’s omitted) 2021 2020 Cash and cash equivalents ​ $ 198 ​ $ 157 Premises and equipment, net ​ 5,618 ​ 5,782 Other assets ​ 57 ​ 48 Total assets ​ $ 5,873 ​ $ 5,987 Accrued interest and other liabilities / Total liabilities ​ $ 0 ​ $ 0 ​ In addition to the assets and liabilities of 706 North Clinton, the minority interest in 706 North Clinton of $2.9 million at December 31, 2021 is included in the Company’s consolidated statements of condition. The creditors of 706 North Clinton do not have a claim on the general assets of the Company. The Company’s maximum loss exposure net of minority interest in 706 North Clinton is approximately $4.2 million as of December 31, 2021, including a $1.2 million loss exposure related to the financing agreement between the other member of 706 North Clinton and the Bank.

SEGMENT INFORMATION

SEGMENT INFORMATION	12 Months Ended
	Dec. 31, 2021
SEGMENT INFORMATION
SEGMENT INFORMATION	NOTE U: 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. 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 operating subsidiaries of BPAS, BPA, BPAS-APS, BPAS Trust Company of Puerto Rico, NRS, GTC, HB&T, and FBD, 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, Carta Group and Wealth Partners, as well as asset management provided by Nottingham; 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). ​ Information about reportable segments and reconciliation of the information to the consolidated financial statements follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Employee ​ ​ ​ ​ ​ ​ ​ Consolidated (000’s omitted) Banking Benefit Services All Other Eliminations Total 2021 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net interest income ​ $ 374,078 ​ $ 293 ​ $ 41 ​ $ 0 ​ $ 374,412 Provision for credit losses ​ ​ (8,839) ​ ​ 0 ​ ​ 0 ​ ​ 0 ​ ​ (8,839) Noninterest revenue ​ ​ 67,910 ​ ​ 116,621 ​ ​ 68,834 ​ ​ (7,130) ​ ​ 246,235 Amortization of intangible assets ​ ​ 4,744 ​ ​ 6,033 ​ ​ 3,274 ​ ​ 0 ​ ​ 14,051 Acquisition expenses ​ ​ 638 ​ ​ 36 ​ ​ 27 ​ ​ 0 ​ ​ 701 Acquisition-related contingent consideration adjustment ​ ​ 0 ​ ​ 200 ​ ​ 0 ​ ​ 0 ​ ​ 200 Other operating expenses ​ ​ 265,525 ​ ​ 64,423 ​ ​ 50,368 ​ ​ (7,130) ​ ​ 373,186 Income before income taxes ​ $ 179,920 ​ $ 46,222 ​ $ 15,206 ​ $ 0 ​ $ 241,348 Assets ​ $ 15,325,732 ​ $ 257,879 ​ $ 97,391 ​ $ (128,345) ​ $ 15,552,657 Goodwill ​ $ 689,868 ​ $ 85,321 ​ $ 23,920 ​ $ 0 ​ $ 799,109 Core deposit intangibles & Other intangibles ​ $ 9,087 ​ $ 40,018 ​ $ 16,121 ​ $ 0 ​ $ 65,226 2020 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net interest income ​ $ 367,237 ​ $ 943 ​ $ 223 ​ $ 0 ​ $ 368,403 Provision for credit losses ​ 14,212 ​ 0 ​ 0 ​ 0 ​ 14,212 Noninterest revenue ​ 69,578 ​ 103,456 ​ 61,599 ​ (6,214) ​ 228,419 Amortization of intangible assets ​ 5,515 ​ 5,724 ​ 3,058 ​ 0 ​ 14,297 Acquisition expenses ​ 4,933 ​ 0 ​ 0 ​ 0 ​ 4,933 Other operating expenses ​ 255,955 ​ 60,709 ​ 46,854 ​ (6,214) ​ 357,304 Income before income taxes ​ $ 156,200 ​ $ 37,966 ​ $ 11,910 ​ $ 0 ​ $ 206,076 Assets ​ $ 13,762,325 ​ $ 217,780 ​ $ 82,849 ​ $ (131,860) ​ $ 13,931,094 Goodwill ​ $ 690,121 ​ $ 83,275 ​ $ 20,312 ​ $ 0 ​ $ 793,708 Core deposit intangibles & Other intangibles ​ $ 13,831 ​ $ 32,051 ​ $ 7,058 ​ $ 0 ​ $ 52,940 2019 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net interest income ​ $ 358,334 ​ $ 665 ​ $ 176 ​ $ 0 ​ $ 359,175 Provision for credit losses ​ 8,430 ​ 0 ​ 0 ​ 0 ​ 8,430 Noninterest revenue ​ 75,067 ​ 99,483 ​ 59,075 ​ (3,006) ​ 230,619 Amortization of intangible assets ​ 5,751 ​ 6,770 ​ 3,435 ​ 0 ​ 15,956 Acquisition expenses ​ 8,608 ​ 0 ​ 0 ​ 0 ​ 8,608 Other operating expenses ​ 245,870 ​ 59,428 ​ 45,170 ​ (3,006) ​ 347,462 Income before income taxes ​ $ 164,742 ​ $ 33,950 ​ $ 10,646 ​ $ 0 ​ $ 209,338 Assets ​ $ 11,225,509 ​ $ 209,690 ​ $ 76,351 ​ $ (101,255) ​ $ 11,410,295 Goodwill ​ $ 670,223 ​ $ 83,275 ​ $ 20,312 ​ $ 0 ​ $ 773,810 Core deposit intangibles & Other intangibles ​ $ 16,418 ​ $ 37,775 ​ $ 8,920 ​ $ 0 ​ $ 63,113 ​

SUBSEQUENT EVENTS

SUBSEQUENT EVENTS	12 Months Ended
	Dec. 31, 2021
SUBSEQUENT EVENTS
SUBSEQUENT EVENTS	NOTE V: SUBSEQUENT EVENTS Companies are required to evaluate events and transactions that occur after the balance sheet date but before the date the financial statements are issued. They must recognize in the financial statements the effect of all events or transactions that provide additional evidence of conditions that existed at the balance sheet date, including the estimates inherent in the financial preparation process. Entities do not recognize the impact of events or transactions that provide evidence about conditions that did not exist at the balance sheet date but arose after that date. Such events and transactions were evaluated through the date these consolidated financial statements were available to be issued and the Company determined that no such events had occurred.

SUMMARY OF SIGNIFICANT ACCOUN_2

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)	12 Months Ended
	Dec. 31, 2021
ACCOUNTING POLICIES
Nature of Operations	Nature of Operations Community Bank System, Inc. (the “Company”) is a registered financial holding company which wholly-owns two significant consolidated subsidiaries: Community Bank, N.A. (the “Bank” or “CBNA”), and Benefit Plans Administrative Services, Inc. (“BPAS”). As of December 31, 2021, BPAS owns five subsidiaries: Benefit Plans Administrative Services, LLC (“BPA”), a provider of defined benefit contribution plan administration services; Northeast Retirement Services, LLC (“NRS”), a provider of institutional transfer agency, master recordkeeping services, fund administration, trust and retirement plan services; BPAS Actuarial & Pension Services, LLC (“BPAS-APS”), a provider of actuarial and benefit consulting services; BPAS Trust Company of Puerto Rico, a Puerto Rican trust company; and Hand Benefits & Trust Company (“HB&T”), a provider of collective investment fund administration and institutional trust services. BPA owns one subsidiary, Fringe Benefits Design of Minnesota, Inc. ("FBD"), a provider of retirement plan administration and benefit consulting services. NRS owns one subsidiary, Global Trust Company, Inc. (“GTC”), a non-depository trust company which provides fiduciary services for collective investment trusts and other products. HB&T owns one subsidiary, Hand Securities Inc. (“HSI”), an introducing broker-dealer. As of December 31, 2021, the Bank operated 206 full-service branches and 12 drive-thru only locations operating as Community Bank, N.A. throughout 42 counties of Upstate New York, six counties of Northeastern Pennsylvania, 12 counties of Vermont and one county of Western Massachusetts, offering a range of commercial and retail banking services. The Bank owns the following operating subsidiaries: The Carta Group, Inc. (“Carta Group”), CBNA Preferred Funding Corporation (“PFC”), CBNA Treasury Management Corporation (“TMC”), Community Investment Services, Inc. (“CISI”), Nottingham Advisors, Inc. (“Nottingham”), OneGroup NY, Inc. (“OneGroup”), OneGroup Wealth Partners, Inc. ("Wealth Partners") and Oneida Preferred Funding II LLC (“OPFC II”). OneGroup is a full-service insurance agency offering personal and commercial lines of insurance and other risk management products and services. PFC and OPFC II primarily act as investors in residential and commercial real estate activities. TMC provides cash management, investment, and treasury services to the Bank. CISI, Carta Group and Wealth Partners provide broker-dealer and investment advisory services. Nottingham provides asset management services to individuals, corporations, corporate pension and profit sharing plans, and foundations.
Principles of Consolidation	Principles of Consolidation The consolidated financial statements include the accounts of the Company and its subsidiaries. All intercompany accounts and transactions have been eliminated in consolidation. Variable Interest Entities (“VIE”) are legal entities in which equity investors do not have the characteristics of a controlling financial interest or do not have sufficient equity at risk for the legal entities to finance its activities without additional subordinated financial support. VIEs may be required to be consolidated by a company if it is determined the company is the primary beneficiary of a VIE. The primary beneficiary of a VIE is the enterprise that has: (1) the power to direct the activities of the VIE that most significantly impact the VIE’s economic performance, and (2) the obligation to absorb losses of the VIE that could potentially be significant to the VIE or the right to receive benefits of the VIE that could potentially be significant to the VIE. The Company’s VIE’s are described in more detail in Note T to the consolidated financial statements.
Critical Accounting Estimates in the Preparation of Financial Statements	Critical Accounting Estimates in the Preparation of Financial Statements The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. Critical accounting estimates include the allowance for credit losses, actuarial assumptions associated with the pension, post-retirement and other employee benefit plans, the provision for income taxes, investment valuation, the carrying value of goodwill and other intangible assets, the fair value of contingent consideration liabilities, and acquired loan valuations.
Risk and Uncertainties	Risk and Uncertainties In the normal course of its business, the Company encounters economic and regulatory risks. There are three main components of economic risk: interest rate risk, credit risk and market risk. The Company is subject to interest rate risk to the degree that its interest-bearing liabilities mature or reprice at different speeds, or on a different basis, from its interest-earning assets. The Company’s primary credit risk is the risk of default on the Company’s loan portfolio that results from the borrowers’ inability or unwillingness to make contractually required payments. Market risk reflects potential changes in the value of collateral underlying loans, the fair value of investment securities, and loans held for sale. The Company is subject to regulations of various governmental agencies. These regulations can change significantly from period to period. The Company also undergoes periodic examinations by the regulatory agencies which may subject it to further changes with respect to asset valuations, amounts of required credit loss allowances, and operating restrictions resulting from the regulators’ judgments based on information available to them at the time of their examinations. The extent to which the ongoing coronavirus pandemic ("COVID-19") impacts the Company's business and financial results depends on numerous evolving factors including, but not limited to: the magnitude and duration of COVID-19, the extent to which it continues to impact national and international macroeconomic conditions including interest rates, unemployment rates, the trajectory of the ongoing economic recovery, and governmental and business reactions to the pandemic. The Company assessed certain accounting matters that generally require consideration of forecasted financial information in context with the information reasonably available to the Company and the unknown future impacts of COVID-19 as of December 31, 2021 and through the date of this Annual Report on Form 10-K. The accounting matters assessed included, but were not limited to, the Company's allowance for credit losses, changes in fee and interest income, and the carrying value of goodwill and other long-lived assets.
Revenue Recognition	Revenue Recognition The Company recognizes revenue in accordance with 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. 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. 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 December 31, 2021, $31.6 million of accounts receivable, including $9.1 million of unbilled fee revenue, and $2.2 million of unearned revenue was recorded in the consolidated statements of condition. As of December 31, 2020, $30.3 million of accounts receivable, including $7.7 million of unbilled fee revenue, and $1.4 million of unearned revenue was recorded in the consolidated statements of condition. Contract Acquisition Costs Under the guidance 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.
Cash and Cash Equivalents	Cash and Cash Equivalents For purposes of reporting cash flows, cash and cash equivalents include cash on hand, amounts due from banks, and highly liquid investments with original maturities of less than 90 days. The carrying amounts reported in the consolidated statements of condition for cash and cash equivalents approximate those assets’ fair values. As of December 31, 2021 and 2020, cash and cash equivalents reported in the consolidated statements of condition included cash due from banks of $11.0 million and $7.7 million, respectively. Cash due from banks may at times exceed federally insured limits.
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. The Company did not use the held-to-maturity classification in 2021 or 2020. 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. None of the Company’s investment securities have been classified as trading securities at December 31, 2021 or 2020. Interest income includes amortization of purchase premiums or discounts. Premiums and discounts on securities are amortized on the level-yield method without anticipating prepayments, except for mortgage-backed securities where prepayments are anticipated. Gains and losses are recorded on the trade date and determined using the specific identification method. 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. Certain equity securities that do not have a readily determinable fair value are stated at cost, 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”) and 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. 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. Allowance for Credit Losses – Debt Securities For held-to-maturity debt securities, the Company measures expected credit losses on a collective basis by major security type. The estimates of expected credit losses considers historical credit loss information that is adjusted for current conditions and reasonable and supportable forecasts. Accrued interest receivable on held-to-maturity securities is excluded from the estimate of credit losses. For available-for-sale debt securities in an unrealized loss position, the Company first assesses whether it intends to sell, or it more likely than not that it will be required to sell the security before recovery of its amortized cost basis. If either of the criteria regarding intent or requirement to sell is met, the security’s amortized cost basis is written down to fair value through income. For available-for-sale debt securities that do not meet the aforementioned criteria, the Company evaluates whether the decline in fair value has resulted from credit losses or other factors. In making this assessment, management considers the security structure, recent security collateral performance metrics, if applicable, external credit ratings, failure of the issuer to make scheduled interest or principal payments, judgment about and expectations of future performance, and relevant independent industry research, analysis, and forecasts. This assessment involves a high degree of subjectivity and judgment that is based on the information available to management at a point in time. If this assessment indicates that a credit loss exists, the present value of the cash flows expected to be collected from the security are compared to the amortized cost basis of the security. If the present value of the cash flows expected to be collected from the security is less than the amortized cost basis of the security, a credit loss exists and an allowance for credit losses is recorded, limited by the amount that the fair value is less than the amortized cost basis. Any impairment that has not been recorded through an allowance for credit losses is recognized in other comprehensive income. Changes in the allowance for credit losses are recorded as provision for (or reversal of) credit losses in the consolidated statements of income. Losses are charged against the allowance when management believes the uncollectibility of an available-for-sale security is confirmed or when either of the criteria regarding intent or requirement to sell is met. Accrued interest receivable on available-for-sale debt securities, included in accrued interest and fees receivable on the consolidated statements of condition, totaled $15.8 million and $13.3 million at December 31, 2021 and 2020, respectively, and is excluded from the estimate of credit losses. Prior to the adoption of ASU No. 2016-13, Financial Instruments – Credit Losses (Topic 326)
Loans	Loans Loans that management has the intent and ability to hold for the foreseeable future or until maturity or payoff are reported at amortized cost, net of allowance for credit losses. Amortized cost is the principal balance outstanding, net of purchase premiums and discounts, and deferred loan fees and costs. Mortgage loans held for sale are carried at fair value and are included in loans held for sale on the consolidated statements of condition. 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. The carrying amount of accrued interest approximates its fair value. Interest on loans is accrued and credited to operations based upon the principal amount outstanding. Nonrefundable loan fees and related direct costs are deferred and included in the loan balances where they are amortized over the life of the loan as an adjustment to loan yield using the effective yield method. Premiums and discounts on purchased loans are amortized using the effective yield method over the life of the loans. Accrued interest receivable on loans is included in accrued interest and fees receivable on the consolidated statements of condition and is excluded from the estimate of credit losses and amortized cost basis of loans. An allowance for credit losses is not measured for accrued interest receivable on loans as the Company writes off the uncollectible accrued interest balance in a timely manner upon recognition of credit deterioration of the underlying loan. The Company places a loan on nonaccrual status when the loan becomes 90 days past due (or sooner, if management concludes collection is doubtful), except when, in the opinion of management, it is well-collateralized and in the process of collection. A loan may be placed on nonaccrual status earlier than 90 days past due if there is deterioration in the financial position of the borrower or if other conditions of the loan so warrant. When a loan is placed on nonaccrual status, uncollected accrued interest is reversed against interest income and the amortization of nonrefundable loan fees and related direct costs is discontinued. Interest income during the period the loan is on nonaccrual status is recorded on a cash basis after recovery of principal is reasonably assured. Nonaccrual loans are returned to accrual status when management determines that the borrower’s performance has improved and that both principal and interest are collectible. This generally requires a sustained period of timely principal and interest payments and a well-documented credit evaluation of the borrower’s financial condition. ​ The Company’s charge-off policy by loan type is as follows: ● Business lending loans are generally charged-off to the extent outstanding principal exceeds the fair value of estimated proceeds from collection efforts, including liquidation of collateral. The charge-off is recognized when the loss becomes reasonably quantifiable. ● Consumer installment loans are generally charged-off to the extent outstanding principal exceeds the fair value of collateral, and are recognized by the end of the month in which the loan becomes 90 days past due. ● Consumer mortgage and home equity loans are generally charged-off to the extent outstanding principal exceeds the fair value of the property, less estimated costs to sell, and are recognized when the loan becomes 180 days past due. ​ Allowance for Credit Losses – Loans The allowance for credit losses is a valuation account that is netted against the loans’ amortized cost basis to present the net amount expected to be collected on the loans. Loans are charged off against the allowance when management believes the uncollectibility of a loan balance is confirmed. Management estimates the allowance balance using relevant available information from internal and external sources relating to past events, current conditions, and reasonable and supportable forecasts. Historical credit loss experience provides the basis for the estimation of expected credit losses. Adjustments are made for differences in current loan-specific risk characteristics such as differences in underwriting standards, portfolio mix, acquired loans, delinquency level, risk ratings or term of loans as well as changes in macroeconomic conditions, such as changes in unemployment rates, property values such as home prices, commercial real estate prices and automobile prices, gross domestic product, recession probability, and other relevant factors. The segments of the Company's loan portfolio are disaggregated into the following classes that allow management to monitor risk and performance: ● Business lending is comprised of general purpose commercial and industrial loans including, but not limited to, agricultural-related and dealer floor plans, loans to not-for-profit enterprises, as well as mortgages on commercial property and Paycheck Protection Program ("PPP") loans. The portfolio segment is further broken into portfolio classes based on risks associated with the collateral supporting the loans. Each class of business lending can also have different payment structures. Business lending loans are generally higher dollar loans and a large portion are risk rated at least annually. ● Consumer mortgages consist primarily of fixed rate residential instruments, typically 10 - 30 years in contractual term, secured by first liens on real property. FICO scores are used to monitor higher risks related to this type of lending with FICO AB referring to higher tiered loans with FICO scores greater than or equal to 720 as compared to FICO CDE with lower FICO scores less than 720 and potentially higher risk. ● Consumer indirect consists primarily of installment loans originated through selected dealerships and are generally secured by automobiles, marine and other recreational vehicles. Collateral securing the loans was used to further disaggregate this portfolio as charge-offs can vary depending on the purpose of the loan. Non-auto loans often have longer terms, and generally have higher risk due to declines in collateral value given the nature of the property. ● Consumer direct consists of all other loans to consumers such as personal installment loans and check credit lines of credit. ● Home equity products are 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 allowance for credit losses is measured on a collective (pool) basis when similar risk characteristics exist, including collateral type, credit ratings/scores, size, duration, interest rate structure, industry, geography, origination vintage, and payment structure. The Company has identified the following portfolio segments and classes and measures the allowance for credit losses using the following methods: ​ ​ ​ ​ ​ ​ Loan Portfolio Segment Loan Portfolio Class Allowance for Credit Losses Methodology Business lending Commercial real estate multi family Cumulative loss rate Business lending Commercial real estate non-owner occupied Cumulative loss rate Business lending Commercial real estate owner occupied Cumulative loss rate Business lending Commercial and industrial loans Vintage loss rate Business lending Commercial and industrial lines of credit Line loss Business lending Municipal Cumulative loss rate Business lending Other business Cumulative loss rate Business lending Paycheck Protection Program Cumulative loss rate Consumer mortgage Consumer mortgage FICO AB Cumulative loss rate Consumer mortgage Consumer mortgage FICO CDE Cumulative loss rate Consumer indirect Indirect new auto Vintage loss rate Consumer indirect Indirect used auto Vintage loss rate Consumer indirect Indirect non-auto Vintage loss rate Consumer direct Consumer check credit Line loss Consumer direct Consumer direct Vintage loss rate Home equity Home equity fixed rate Vintage loss rate Home equity Home equity lines of credit Line loss ​ The cumulative loss rate method uses historical loss data applied against multiple pools of loans and uses a quantitatively based management overlay in order to capture the risk for a loan's entire expected life. These loss rates are then applied to current balances to achieve a required reserve before qualitative adjustments. The line loss method calculates the quantitative required reserve for lines of credit. This method contains several different underlying calculations including average annual loss rate, pay-down rate, cumulative loss, average draw percentage, and undrawn liability reserve. The vintage loss rate method calculates annual loss rates by origination year. The results of this model are then applied to outstanding balances, which correspond to the origination period for each annual loss rate. In addition to the risk characteristics noted above, management considers the portion of acquired loans to the overall segment balance, as well as current delinquency and charge-off trends compared to historical time periods. Loans that do not share risk characteristics are evaluated on an individual basis. Loans that are individually assessed are not included in the collective evaluation. When management determines that foreclosure is probable or when the borrower is experiencing financial difficulty at the reporting date and repayment is expected to be provided substantially through the operation or sale of the collateral, expected credit losses are based on the fair value of the collateral at the reporting date, adjusted for selling costs as appropriate. Expected credit losses are estimated over the contractual term of the loans and adjusted for expected prepayments when appropriate. The contractual term excludes expected extensions, renewals, and modifications unless management has a reasonable expectation at the reporting date that a troubled debt restructuring will be executed with an individual borrower or the extension or renewal options are included in the original or modified contract at the reporting date and are not unconditionally cancellable by the Company. Certain business lending, consumer direct, and home equity loans do not have stated maturities. In determining the estimated life of these loans, management first estimates the future cash flows expected to be received and then applies those expected future cash flows to the balance. Expected credit losses for lines of credit with no stated maturity are determined by estimating the amount and timing of all principal payments expected to be received after the reporting period and allocating those principal payments between the balance outstanding as of the reporting period and the balance of future receivables expected to be originated through subsequent usage of the unconditionally cancellable loan commitment associated with the account until the expected payments have been fully allocated. An additional allowance for credit loss is recorded for the excess of the balance outstanding as of the reporting period over the expected principal payments allocated to that balance. Prior to the adoption of ASU No. 2016-13, Financial Instruments – Credit Losses (Topic 326) Troubled Debt Restructuring A loan for which the terms have been modified resulting in a concession, and for which the borrower is experiencing financial difficulties, is considered to be a troubled debt restructuring ("TDR"). The allowance for credit loss on a TDR is measured using the same method as all other loans, except when the value of a concession cannot be measured using a method other than the discounted cash flow method. When the value of a concession is measured using the discounted cash flow method, the allowance for credit loss is determined by discounting the expected future cash flows at the original interest rate of the loan. Refer to Note D: Loans for the Company's policy regarding COVID-19 related financial hardship payment deferrals. Allowance for Credit Losses - Off-balance-sheet credit exposures The Company estimates expected credit losses over the contractual period in which the Company is exposed to credit risk via a contractual obligation to extend credit, unless that obligation is unconditionally cancellable by the Company. There are unfunded commitments for lines of credit within each of the Company's loan portfolio segments except consumer indirect. The allowance for credit losses on off-balance-sheet credit exposures is adjusted as a provision for (or reversal of) credit losses. The estimate includes consideration of the likelihood that funding will occur and an estimate of expected credit losses on commitments expected to be funded over its estimated life. Management estimates the allowance balance using relevant available information, from internal and external sources, relating to past events, current conditions, and reasonable and supportable forecasts. Historical credit loss experience provides the basis for the estimation of expected credit losses. Adjustments to historical loss information are made for differences in current loan-specific risk characteristics that are the same as the adjustments considered for the loan portfolio. Purchased Credit Deteriorated (“PCD”) Loans The Company has purchased loans, some of which have experienced a more-than-insignificant credit deterioration since origination. The Company's policy for reviewing what meets the threshold of the definition of a more-than-insignificant credit deterioration includes loans that are delinquent more than 30 days, loans that have historical delinquencies of more than 30 days at least three times since origination, risk rating downgrades since origination, loans with multiple payment deferrals, loans considered to be troubled debt restructurings, individually assessed loans or loans with certain documented policy exceptions, further refined based on loan-specific facts and circumstances. PCD loans are initially recorded at the amount paid. An allowance for credit losses is determined using the same methodology as other loans. The initial allowance for credit losses determined on a collective basis is allocated to individual loans. The sum of the loan's purchase price and allowance for credit losses becomes its initial amortized cost basis. The difference between the initial amortized cost basis and the par value of the loan is a noncredit discount or premium, which is amortized into interest income over the life of the loan. Subsequent changes to the allowance for credit losses are recorded as provision for (or reversal of) credit losses. Prior to the adoption of ASU No. 2016-13, Financial Instruments – Credit Losses (Topic 326) on January 1, 2020, acquired loans that had evidence of deterioration in credit quality since origination and for which it was probable, at acquisition, that the Company would be unable to collect all contractually required payments were accounted for as impaired loans under ASC 310-30. Acquired impaired loans were initially recorded at fair value with no initial allowance for credit losses recorded at acquisition. Non-Purchased Credit Deteriorated (“non-PCD”) Loans Acquired loans that are not deemed to have experienced a more-than-insignificant credit deterioration since origination are considered non-PCD. At the acquisition date, a fair value adjustment is recorded that includes both credit and interest rate considerations. Fair value adjustments may be discounts (or premiums) to a loan’s cost basis and are accreted (or amortized) to net interest income (or expense) over the loan’s remaining life. Fair value adjustments for revolving loans are accreted (or amortized) using a straight line method. Term loans are accreted (or amortized) using the constant effective yield method. A provision for credit losses is also recorded at acquisition for the credit considerations on non-PCD loans. Subsequent to the purchase date, the methods utilized to estimate the required allowance for credit losses for these loans are the same as originated loans and subsequent changes to the allowance for credit losses are recorded as provision for (or reversal of) credit losses. Prior to the adoption of ASU No. 2016-13, Financial Instruments – Credit Losses (Topic 326) on January 1, 2020, acquired loans that did not meet the requirements under ASC 310-30 were considered acquired non-impaired loans and were accounted for in accordance with ASC 310-20. Acquired non-impaired loans were initially recorded at fair value with no initial allowance for credit losses recorded at acquisition.
Intangible Assets	Intangible Assets Intangible assets include core deposit intangibles, customer relationship intangibles and goodwill arising from acquisitions. Core deposit intangibles and customer relationship intangibles are amortized on either an accelerated or straight-line basis over periods ranging from seven The Company evaluates goodwill for impairment on an annual basis, or more often if events or circumstances indicate there may be impairment. The implied fair value of a reporting unit’s goodwill is compared to its carrying amount and the impairment loss is measured by the excess of the carrying value over fair value. The fair value of each reporting unit is compared to the carrying amount of that reporting unit in order to determine if impairment is indicated.
Premises and Equipment	Premises and Equipment Premises and equipment are stated at cost less accumulated depreciation. Computer software costs that are capitalized include only external direct costs of obtaining and installing the software. The Company has not developed any internal use software. Depreciation is calculated using the straight-line method over the estimated useful lives of the assets. Useful lives range from two three and hardware
Leases	Leases The Company occupies certain offices and uses certain equipment under non-cancelable operating lease agreements. The Company determines if an arrangement is a lease at inception. The right-of-use assets associated with operating leases are recorded in premises and equipment in the Company’s consolidated statements of condition. The lease liabilities associated with operating leases are included in accrued interest and other liabilities in the Company’s consolidated statements of condition. Right-of-use assets represent the Company’s right to use the underlying assets for the lease term and lease liabilities represent the Company’s obligation to make lease payments arising from the associated leases. Operating lease right-of-use assets and liabilities are recognized at the commencement date of the lease based on the present value of lease payments over the lease term. The Company uses interest rates on advances from the FHLB available at the time of commencement to determine the present value of lease payments. The operating lease right-of-use assets include any lease payments made at the time of commencement and exclude lease incentives. The Company’s lease terms may include options to extend or terminate the lease when it is reasonably certain that the option will be exercised. Lease expense is recognized on a straight-line basis over the lease term and is included in occupancy and equipment expense in the Company’s consolidated statements of income. The Company elected to account for lease and non-lease components separately, applies a portfolio approach to account for the lease right-of-use assets and liabilities for certain equipment leases and elected to exclude leases with a term of 12 months or less from the recognition and measurement policies described above.
Other Real Estate	Other Real Estate Other real estate owned is comprised of properties acquired through foreclosure, or by deed in lieu of foreclosure. These assets are carried at fair value less estimated costs of disposal. At foreclosure, if the fair value, less estimated costs to sell, of the real estate acquired is less than the Company’s recorded investment in the related loan, a write-down is recognized through a charge to the allowance for credit losses. Any subsequent reduction in value is recognized by a charge to income. Operating costs associated with the properties are charged to expense as incurred. At December 31, 2021 and 2020, other real estate totaled $0.7 million and $0.9 million, respectively, and is included in other assets.
Mortgage Servicing Rights	Mortgage Servicing Rights 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 period of estimated net servicing income or loss. The Company uses a valuation model that calculates the present value of future cash flows to determine the fair value of servicing rights. In using this valuation method, the Company incorporates assumptions that market participants would use in estimating future net servicing income, which includes estimates of the servicing cost per loan, the discount rate, and prepayment speeds. The carrying value of the originated mortgage servicing rights is included in other assets and is evaluated quarterly for impairment using these same market assumptions. The amount of impairment recognized is the amount by which the carrying value of the capitalized servicing rights for a stratum exceeds estimated fair value. Impairment is recognized through a valuation allowance.
Treasury Stock	Treasury Stock Repurchases of shares of the Company’s common stock are recorded at cost as a reduction of shareholders’ equity. Reissuance of shares of treasury stock is recorded at average cost.
Income Taxes	Income Taxes The Company and its subsidiaries file a consolidated federal income tax return. Provision for income taxes is based on taxes currently payable or refundable as well as deferred taxes that are based on temporary differences between the tax basis of assets and liabilities and their reported amounts in the consolidated financial statements. Deferred tax assets and liabilities are reported in the consolidated financial statements at currently enacted income tax rates applicable to the period in which the deferred tax assets and liabilities are expected to be realized or settled. Benefits from tax positions should be recognized in the financial statements only when it is more likely than not that the tax position will be sustained upon examination by the appropriate taxing authority having full knowledge of all relevant information. A tax position meeting the more-likely-than-not recognition threshold should be measured at the largest amount of benefit for which the likelihood of realization upon ultimate settlement exceeds 50 percent. Should tax laws change or the taxing authorities determine that management’s assumptions were inappropriate, an adjustment may be required which could have a material effect on the Company’s results of operations.
Investments in Real Estate Limited Partnerships	Investments in Real Estate Limited Partnerships The Company has investments in various real estate limited partnerships that acquire, develop, own and operate low and moderate-income housing. The Company’s ownership interest in these limited partnerships ranges from 5.00% to 99.99% as of December 31, 2021. These investments are made directly in Low Income Housing Tax Credit, or LIHTC, partnerships formed by third parties. As a limited partner in these operating partnerships, the Company receives tax credits and tax deductions for losses incurred by the underlying properties. The Company accounts for its ownership interest in LIHTC partnerships in accordance with Accounting Standards Update (“ASU”) 2014-01, Investments – Equity Method and Joint Ventures (Topic 323): Accounting for Investments in Qualified Affordable Housing Projects
Repurchase Agreements	Repurchase Agreements The Company sells certain securities under agreements to repurchase. These agreements are treated as collateralized financing transactions. These secured borrowings are reflected as liabilities in the accompanying consolidated statements of condition and are recorded at the amount of cash received in connection with the transaction. Short-term securities sold under agreements to repurchase generally mature within one day from the transaction date. Securities, generally U.S. government and agency securities, pledged as collateral under these financing arrangements can be repledged by the secured party. Additional collateral may be required based on the fair value of the underlying securities.
Retirement Benefits	Retirement Benefits The Company provides defined benefit pension benefits to eligible employees and post-retirement health and life insurance benefits to certain eligible retirees. The Company also provides deferred compensation and supplemental executive retirement plans for selected current and former employees, officers, and directors. Expense under these plans is charged to current operations and consists of several components of net periodic benefit cost based on various actuarial assumptions regarding future experience under the plans, including discount rate, rate of future compensation increases and expected return on plan assets.
Derivative Financial Instruments and Hedging Activities	Derivative Financial Instruments and Hedging Activities The Company accounts for derivative financial instruments at fair value. If certain conditions are met, a derivative may be specifically designated as (1) a hedge of the exposure to changes in the fair value of a recognized asset or liability or an unrecognized firm commitment (“fair value hedge”), (2) a hedge of the exposure to variable cash flows of a forecasted transaction or the variability of cash flows to be received or paid related to a recognized asset or liability (“cash flow hedge”), or (3) an instrument with no hedging designation (“stand-alone derivative”). For a fair value hedge, the gain or loss on the derivative, as well as the offsetting loss or gain on the hedged item, are recognized in current earnings as fair values change. For a cash flow hedge, the gain or loss on the derivative is reported in other comprehensive income and is reclassified into earnings in the same periods during which the hedged transaction affects earnings. Changes in the fair value of derivatives that do not qualify for hedge accounting are reported currently in earnings, as noninterest revenues. Net cash settlements on derivatives that qualify for hedge accounting are recorded in interest income or interest expense, based on the item being hedged. Net cash settlements on derivatives that do not qualify for hedge accounting are reported in noninterest revenues. Cash flows on hedges are classified in the consolidated statement of cash flow statement the same as the cash flows of the items being hedged. The Company formally documents the relationship between derivatives and hedged items, as well as the risk-management objective and strategy for undertaking hedge transactions at the inception of the hedging relationship. This documentation includes linking the fair value or cash flow hedges to specific assets and liabilities on the statement of condition or to specific commitments or forecasted transactions. When hedge accounting is discontinued, subsequent changes in fair value of the derivative are recorded in noninterest revenues. When a fair value hedge is discontinued, the hedged asset or liability is no longer adjusted for changes in fair value and the existing basis adjustment is amortized or accreted over the remaining life of the asset or liability. When a cash flow hedge is discontinued, but the hedged cash flows or forecasted transactions are still expected to occur, gains or losses that were accumulated in other comprehensive income are amortized into earnings over the same periods which the hedged transactions will affect earnings.
Assets Under Management or Administration	Assets Under Management or Administration Assets held in fiduciary or agency capacities for customers are not included in the accompanying consolidated statements of condition as they are not assets of the Company. All fees associated with providing asset management services are recorded on an accrual basis of accounting and are included in noninterest income.
Advertising	Advertising Advertising costs, which are nondirect response in nature and expensed as incurred, totaled approximately $5.2 million, $6.1 million and $7.1 million for the years ending December 31, 2021,2020 and 2019, respectively.
Bank Owned Life Insurance	Bank Owned Life Insurance The Company owns life insurance policies on certain current and former employees and directors where the Bank is the beneficiary. Bank owned life insurance is recorded at the amount that can be realized under the insurance contract at the balance sheet date, which is the cash surrender value (“CSV”) adjusted for other charges or other amounts due that are probable at settlement. Increases in the CSV of the policies, as well as the death benefits received, net of any CSV, are recorded in noninterest income, and are not subject to income taxes.
Earnings Per Share	Earnings Per Share Using the two-class method, basic earnings per common share is computed based upon net income available to common shareholders divided by the weighted average number of common shares outstanding during each period, which excludes the outstanding unvested restricted stock. Diluted earnings per share is computed using the weighted average number of common shares determined for the basic earnings per common share computation plus the dilutive effect of stock options using the treasury stock method. Stock options where the exercise price is greater than the average market price of common shares were not included in the computation of earnings per diluted share as they would have been anti-dilutive. Shares held in rabbi trusts related to deferred compensation plans are considered outstanding for purposes of computing earnings per share.
Stock-based Compensation	Stock-based Compensation Companies are required to measure and record compensation expense for stock options and other share-based payments on the instruments’ fair value on the date of grant. Stock-based compensation expense is recognized ratably over the requisite service period for all awards (see Note L).
Fair Values of Financial Instruments	Fair Values of Financial Instruments The Company determines fair values based on quoted market values where available or on estimates using present values or other valuation techniques. Those techniques are significantly affected by the assumptions used, including 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, could not be realized in immediate settlement of the instrument. Certain financial instruments and all nonfinancial instruments are excluded from this disclosure requirement. Accordingly, the aggregate fair value amounts presented do not represent the underlying value of the Company. The fair values of investment securities, loans, deposits, and borrowings have been disclosed in Note R. Contingent Consideration The Company measures contingent consideration liabilities recognized in connection with business combinations at fair value on a recurring basis using significant unobservable inputs classified within Level 3 of the fair value hierarchy as defined in ASC 820 Fair Value Measurement
Reclassifications	Reclassifications Certain reclassifications have been made to prior years’ balances to conform to the current year presentation.
Recently Adopted Accounting Pronouncements	Recently Adopted Accounting Pronouncements In August 2018, the FASB issued ASU No. 2018-14, Disclosure Framework - Changes to the Disclosure Requirements for Defined Benefit Plans (Subtopic 715-20) In December 2019, the FASB issued ASU No. 2019-12, Simplifying the Accounting for Income Taxes (Topic 740) In August 2021, the FASB issued ASU 2021-06, Presentation of Financial Statements (Topic 205) Financial Services-Depository and Lending (Topic 942) Financial Services-Investment Companies (Topic 946): Amendments to SEC Paragraphs Pursuant to SEC Final Rule Releases No. 33-10786 Amendments to Financial Disclosures about Acquired and Disposed Businesses No. 33-10835 Update of Statistical Disclosures for Bank and Savings and Loan Registrants Amendments to Financial Disclosures about Acquired and Disposed Businesses Update of Statistical Disclosures for Bank and Savings and Loan Registrants
New Accounting Pronouncements	New Accounting Pronouncements In March 2020, the FASB issued ASU No. 2020-04, Facilitation of the Effects of Reference Rate Reform on Financial Reporting (Topic 848) . The updated guidance provides optional expedients and exceptions for applying GAAP to contracts, hedging relationships, and other transactions affected by reference rate reform if certain criteria are met. The amendments in this guidance apply only to contracts, hedging relationships, and other transactions that reference LIBOR or another reference rate expected to be discontinued because of reference rate reform. This new guidance is effective as of March 12, 2020 through December 31, 2022. Adoption is permitted in any interim periods for which financial statements have not been issued. The Company has not yet fully adopted this standard. The Company has established a working group that includes multiple functions to guide the transition from LIBOR to alternative reference rates. The Company has identified all known LIBOR exposures, created a preliminary plan to address the exposures, and new originations either do not utilize LIBOR or replacement rate language, provisions, and conventions have been specified. The Company continues to evaluate its exposure to LIBOR and communicate with all stakeholders in order to facilitate the transition. As the Company's exposure to LIBOR-based loans and financial instruments is insignificant, the Company does not expect the adoption of this standard will have a material impact on the Company's consolidated financial statements.

BASIS OF PRESENTATION (Tables)

BASIS OF PRESENTATION (Tables)	12 Months Ended
	Dec. 31, 2021
ACCOUNTING POLICIES
Schedule of portfolio segments and allowances for credit losses	​ ​ ​ ​ ​ ​ Loan Portfolio Segment Loan Portfolio Class Allowance for Credit Losses Methodology Business lending Commercial real estate multi family Cumulative loss rate Business lending Commercial real estate non-owner occupied Cumulative loss rate Business lending Commercial real estate owner occupied Cumulative loss rate Business lending Commercial and industrial loans Vintage loss rate Business lending Commercial and industrial lines of credit Line loss Business lending Municipal Cumulative loss rate Business lending Other business Cumulative loss rate Business lending Paycheck Protection Program Cumulative loss rate Consumer mortgage Consumer mortgage FICO AB Cumulative loss rate Consumer mortgage Consumer mortgage FICO CDE Cumulative loss rate Consumer indirect Indirect new auto Vintage loss rate Consumer indirect Indirect used auto Vintage loss rate Consumer indirect Indirect non-auto Vintage loss rate Consumer direct Consumer check credit Line loss Consumer direct Consumer direct Vintage loss rate Home equity Home equity fixed rate Vintage loss rate Home equity Home equity lines of credit Line loss

ACQUISITIONS (Tables)

ACQUISITIONS (Tables)	12 Months Ended
	Dec. 31, 2021
ACQUISITIONS
Schedule of 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: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2021 ​ ​ 2020 ​ 2019 (000s omitted) TGA ​ FBD NuVantage Total ​ ​ Steuben Total (1) Consideration: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Cash $ 11,620 ​ $ 15,350 ​ $ 2,900 ​ $ 29,870 ​ $ 21,613 ​ $ 95,034 Community Bank System, Inc. common stock ​ 0 ​ 0 ​ 0 ​ 0 ​ ​ 76,942 ​ 0 Contingent consideration ​ 1,500 ​ ​ 1,400 ​ ​ 0 ​ ​ 2,900 ​ ​ 0 ​ ​ 0 Total net consideration ​ 13,120 ​ 16,750 ​ 2,900 ​ 32,770 ​ ​ 98,555 ​ 95,034 Recognized amounts of identifiable assets acquired and liabilities assumed: ​ ​ ​ ​ ​ ​ ​ ​ ​ Cash and cash equivalents ​ 0 ​ 541 ​ 0 ​ 541 ​ ​ 55,973 ​ 90,381 Investment securities ​ 0 ​ 0 ​ 0 ​ 0 ​ ​ 180,497 ​ 39,770 Loans, net of allowance for credit losses on PCD loans (2) ​ 0 ​ 0 ​ 0 ​ 0 ​ ​ 339,017 ​ 479,877 Premises and equipment, net ​ 279 ​ 282 ​ 199 ​ 760 ​ ​ 7,764 ​ 13,970 Accrued interest and fees receivable ​ 0 ​ 0 ​ 0 ​ 0 ​ ​ 2,701 ​ 1,130 Other assets ​ 0 ​ 579 ​ 0 ​ 579 ​ ​ 17,675 ​ 14,109 Core deposit intangibles ​ 0 ​ 0 ​ 0 ​ 0 ​ ​ 2,928 ​ 3,573 Other intangibles ​ 10,900 ​ 14,000 ​ 1,437 ​ 26,337 ​ ​ 1,196 ​ 1,650 Deposits ​ 0 ​ 0 ​ 0 ​ 0 ​ ​ (516,274) ​ (568,161) Other liabilities ​ (229) ​ (698) ​ (174) ​ (1,101) ​ ​ (4,841) ​ (2,922) Other Federal Home Loan Bank borrowings ​ 0 ​ 0 ​ 0 ​ 0 ​ ​ (6,000) ​ (2,420) Subordinated notes payable ​ 0 ​ 0 ​ 0 ​ 0 ​ ​ 0 ​ (13,831) Subordinated debt held by unconsolidated subsidiary trusts ​ 0 ​ 0 ​ 0 ​ 0 ​ ​ (2,062) ​ (2,062) Total identifiable assets, net ​ 10,950 ​ 14,704 ​ 1,462 ​ 27,116 ​ ​ 78,574 ​ 55,064 Goodwill $ 2,170 ​ $ 2,046 ​ $ 1,438 ​ $ 5,654 ​ $ 19,981 ​ $ 39,970 ​ (1) Includes amounts related to the Kinderhook and both CISI acquisitions completed in 2019. (2) Acquisition-related allowance for credit losses on purchased credit deteriorated ("PCD") loans applicable beginning in 2020.
Schedule of loans acquired	​ ​ ​ ​ ​ (000s omitted) PCD Loans Par value of PCD loans at acquisition ​ $ 35,906 Allowance for credit losses at acquisition ​ (668) Non-credit premium at acquisition ​ 103 Fair value of PCD loans at acquisition ​ $ 35,341 ​ The following is a summary of the remaining loans acquired from Steuben for which there was no evidence of a more-than-insignificant deterioration in credit quality since origination at the date of acquisition: ​ ​ ​ ​ ​ (000s omitted) Non-PCD Loans Contractually required principal and interest at acquisition ​ $ 400,738 Contractual cash flows not expected to be collected ​ (2,994) Expected cash flows at acquisition ​ 397,744 Interest component of expected cash flows ​ (94,068) Fair value of non-PCD loans at acquisition ​ $ 303,676 ​ The following is a summary of the loans acquired from Kinderhook at the date of acquisition: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Acquired ​ Acquired ​ Total ​ ​ Impaired ​ Non-impaired ​ Acquired (000s omitted) Loans Loans Loans Contractually required principal and interest at acquisition ​ $ 13,350 ​ $ 636,384 ​ $ 649,734 Contractual cash flows not expected to be collected ​ (4,176) ​ (5,472) ​ (9,648) Expected cash flows at acquisition ​ 9,174 ​ 630,912 ​ 640,086 Interest component of expected cash flows ​ (551) ​ (159,658) ​ (160,209) Fair value of acquired loans ​ $ 8,623 ​ $ 471,254 ​ $ 479,877 ​ The fair value of the Company’s common stock issued for the Steuben acquisition was determined using the market close price of the stock on June 12, 2020. ​
Schedule of pro forma financial information	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Pro Forma (Unaudited) ​ ​ Year Ended December 31, (000s omitted) 2020 2019 Total revenue, net of interest expense ​ $ 607,382 ​ $ 626,229 Net income ​ 171,147 ​ 180,237

INVESTMENT SECURITIES (Tables)

INVESTMENT SECURITIES (Tables)	12 Months Ended
	Dec. 31, 2021
INVESTMENT SECURITIES.
Schedule of amortized cost and estimated fair value of investment securities	The amortized cost and estimated fair value of investment securities as of December 31 are as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2021 2020 ​ ​ ​ ​ ​ Gross ​ Gross ​ ​ ​ ​ ​ ​ ​ Gross ​ Gross ​ ​ ​ ​ ​ Amortized ​ Unrealized ​ Unrealized ​ Estimated ​ Amortized ​ Unrealized ​ Unrealized ​ Estimated (000’s omitted) Cost Gains Losses Fair Value Cost Gains Losses Fair Value Available-for-Sale Portfolio: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ U.S. Treasury and agency securities ​ $ 4,064,624 ​ $ 39,997 ​ $ 106,057 ​ $ 3,998,564 ​ $ 2,423,236 ​ $ 94,741 ​ $ 16,595 ​ $ 2,501,382 Obligations of state and political subdivisions ​ ​ 413,019 ​ ​ 17,326 ​ ​ 56 ​ ​ 430,289 ​ ​ 451,028 ​ ​ 24,632 ​ ​ 0 ​ ​ 475,660 Government agency mortgage-backed securities ​ ​ 474,506 ​ ​ 7,615 ​ ​ 5,065 ​ ​ 477,056 ​ ​ 506,540 ​ ​ 16,280 ​ ​ 182 ​ ​ 522,638 Corporate debt securities ​ ​ 8,000 ​ ​ 39 ​ ​ 77 ​ ​ 7,962 ​ ​ 4,499 ​ ​ 137 ​ ​ 1 ​ ​ 4,635 Government agency collateralized mortgage obligations ​ ​ 19,953 ​ ​ 410 ​ ​ 24 ​ ​ 20,339 ​ ​ 42,476 ​ ​ 1,111 ​ ​ 10 ​ ​ 43,577 Total available-for-sale portfolio ​ $ 4,980,102 ​ $ 65,387 ​ $ 111,279 ​ $ 4,934,210 ​ $ 3,427,779 ​ $ 136,901 ​ $ 16,788 ​ $ 3,547,892 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Equity and other Securities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Equity securities, at fair value ​ $ 251 ​ $ 212 ​ $ 0 ​ $ 463 ​ $ 251 ​ $ 194 ​ $ 0 ​ $ 445 Federal Home Loan Bank common stock ​ 7,188 ​ 0 ​ 0 ​ 7,188 ​ 7,468 ​ 0 ​ 0 ​ 7,468 Federal Reserve Bank common stock ​ 33,916 ​ 0 ​ 0 ​ 33,916 ​ 33,916 ​ 0 ​ 0 ​ 33,916 Other equity securities, at adjusted cost ​ 2,562 ​ 750 ​ 0 ​ 3,312 ​ 4,876 ​ 750 ​ 0 ​ 5,626 Total equity and other securities ​ $ 43,917 ​ $ 962 ​ $ 0 ​ $ 44,879 ​ $ 46,511 ​ $ 944 ​ $ 0 ​ $ 47,455 ​
Schedule 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 for less than or greater than twelve months is as follows: As of December 31, 2021 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Less than 12 Months 12 Months or Longer Total ​ ​ ​ ​ ​ ​ ​ Gross ​ ​ ​ ​ ​ ​ Gross ​ ​ ​ ​ ​ ​ Gross ​ ​ ​ ​ ​ ​ Unrealized ​ ​ ​ ​ ​ Unrealized ​ ​ ​ ​ ​ Unrealized (000’s omitted) # Fair Value Losses # Fair Value Losses # Fair Value Losses Available-for-Sale Portfolio: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ U.S. Treasury and agency securities ​ 47 ​ $ 1,224,101 ​ $ 14,873 ​ 13 ​ $ 900,462 ​ $ 91,184 ​ 60 ​ $ 2,124,563 ​ $ 106,057 Obligations of state and political subdivisions ​ 27 ​ 23,966 ​ 56 ​ 0 ​ 0 ​ 0 ​ 27 ​ 23,966 ​ 56 Government agency mortgage-backed securities ​ 147 ​ 139,442 ​ 2,475 ​ 52 ​ 67,273 ​ 2,590 ​ 199 ​ 206,715 ​ 5,065 Corporate debt securities ​ 1 ​ ​ 4,923 ​ ​ 77 ​ 0 ​ ​ 0 ​ ​ 0 ​ 1 ​ ​ 4,923 ​ ​ 77 Government agency collateralized mortgage obligations ​ 18 ​ 3,146 ​ 24 ​ 1 ​ 53 ​ 0 ​ 19 ​ 3,199 ​ 24 Total available-for-sale investment portfolio ​ 240 ​ $ 1,395,578 ​ $ 17,505 ​ 66 ​ $ 967,788 ​ $ 93,774 ​ 306 ​ $ 2,363,366 ​ $ 111,279 ​ As of December 31, 2020 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Less than 12 Months 12 Months or Longer Total ​ ​ ​ ​ ​ ​ ​ Gross ​ ​ ​ ​ ​ ​ Gross ​ ​ ​ ​ ​ ​ Gross ​ ​ ​ ​ ​ ​ Unrealized ​ ​ ​ ​ ​ Unrealized ​ ​ ​ ​ ​ Unrealized (000’s omitted) # Fair Value Losses # Fair Value Losses # Fair Value Losses Available-for-Sale Portfolio: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ U.S. Treasury and agency securities ​ 13 ​ $ 831,015 ​ $ 16,595 ​ 0 ​ $ 0 ​ $ 0 ​ 13 ​ $ 831,015 ​ $ 16,595 Obligations of state and political subdivisions ​ 1 ​ 358 ​ 0 ​ 0 ​ 0 ​ 0 ​ 1 ​ 358 ​ 0 Government agency mortgage-backed securities ​ 89 ​ 75,992 ​ 182 ​ 2 ​ 14 ​ 0 ​ 91 ​ 76,006 ​ 182 Corporate debt securities ​ 1 ​ ​ 1,001 ​ ​ 1 ​ 0 ​ ​ 0 ​ ​ 0 ​ 1 ​ ​ 1,001 ​ ​ 1 Government agency collateralized mortgage obligations ​ 13 ​ 5,246 ​ 10 ​ 1 ​ 0 ​ 0 ​ 14 ​ 5,246 ​ 10 Total available-for-sale investment portfolio ​ 117 ​ $ 913,612 ​ $ 16,788 ​ 3 ​ $ 14 ​ $ 0 ​ 120 ​ $ 913,626 ​ $ 16,788 ​
Schedule of amortized cost and estimated fair value of debt securities by contractual maturity	The amortized cost and estimated fair value of debt securities at December 31, 2021, 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 ​ ​ Amortized ​ ​ (000’s omitted) Cost Fair Value Due in one year or less ​ $ 156,262 ​ $ 158,119 Due after one through five years ​ 876,849 ​ 891,772 Due after five years through ten years ​ 1,958,202 ​ 1,962,453 Due after ten years ​ 1,494,330 ​ 1,424,471 Subtotal ​ 4,485,643 ​ 4,436,815 Government agency mortgage-backed securities ​ 474,506 ​ 477,056 Government agency collateralized mortgage obligations ​ 19,953 ​ 20,339 Total ​ $ 4,980,102 ​ $ 4,934,210 ​

LOANS (Tables)

LOANS (Tables)	12 Months Ended
	Dec. 31, 2021
Loans and Leases Receivable Disclosure [Line Items]
Schedule of loans receivable, net	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (000’s omitted) ​ 2021 2020 Business lending ​ $ 3,075,904 ​ $ 3,440,077 Consumer mortgage ​ 2,556,114 ​ 2,401,499 Consumer indirect ​ 1,189,749 ​ 1,021,885 Consumer direct ​ 153,811 ​ 152,657 Home equity ​ 398,061 ​ 399,834 Gross loans, including deferred origination costs ​ 7,373,639 ​ 7,415,952 Allowance for credit losses ​ (49,869) ​ (60,869) Loans, net of allowance for credit losses ​ $ 7,323,770 ​ $ 7,355,083 ​
Schedule of aggregate amounts loaned to related parties	Certain directors and executive officers of the Company, as well as associates of such persons, are loan customers. Loans to these individuals were made in the ordinary course of business under normal credit terms and do not have more than a normal risk of collection. Following is a summary of the aggregate amount of such loans during 2021 and 2020. ​ ​ ​ ​ ​ ​ ​ ​ (000’s omitted) 2021 2020 Balance at beginning of year ​ $ 15,549 ​ $ 17,486 New loans ​ 2,500 ​ 4,194 Payments ​ (4,276) ​ (6,131) Balance at end of year ​ $ 13,773 ​ $ 15,549
Schedule of aged analysis of past due loans by class	The following table presents the aging of the amortized cost basis of the Company’s past due loans, including purchased credit deteriorated (“PCD”) loans, by segment as of December 31, 2021 and 2020: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Past Due ​ 90+ Days Past ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (000’s omitted) ​ 30 – 89 ​ Due and ​ ​ ​ ​ Total ​ ​ ​ ​ ​ ​ December 31, 2021 Days Still Accruing Nonaccrual Past Due Current Total Loans Business lending ​ $ 5,540 ​ $ 99 ​ $ 24,105 ​ $ 29,744 ​ $ 3,046,160 ​ $ 3,075,904 Consumer mortgage ​ 10,297 ​ 3,328 ​ 15,027 ​ 28,652 ​ 2,527,462 ​ 2,556,114 Consumer indirect ​ 9,611 ​ 87 ​ 0 ​ 9,698 ​ 1,180,051 ​ 1,189,749 Consumer direct ​ 796 ​ 22 ​ 1 ​ 819 ​ 152,992 ​ 153,811 Home equity ​ 1,778 ​ 272 ​ 2,532 ​ 4,582 ​ 393,479 ​ 398,061 Total ​ $ 28,022 ​ $ 3,808 ​ $ 41,665 ​ $ 73,495 ​ $ 7,300,144 ​ $ 7,373,639 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Past Due ​ 90+ Days Past ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (000’s omitted) ​ 30 – 89 ​ Due and ​ ​ ​ ​ Total ​ ​ ​ ​ ​ ​ December 31, 2020 Days Still Accruing Nonaccrual Past Due Current Total Loans Business lending ​ $ 4,896 ​ $ 59 ​ $ 55,709 ​ $ 60,664 ​ $ 3,379,413 ​ $ 3,440,077 Consumer mortgage ​ 13,236 ​ 3,051 ​ 14,970 ​ 31,257 ​ 2,370,242 ​ 2,401,499 Consumer indirect ​ 13,161 ​ 219 ​ 1 ​ 13,381 ​ 1,008,504 ​ 1,021,885 Consumer direct ​ 1,170 ​ 28 ​ 3 ​ 1,201 ​ 151,456 ​ 152,657 Home equity ​ 2,296 ​ 565 ​ 2,246 ​ 5,107 ​ 394,727 ​ 399,834 Total ​ $ 34,759 ​ $ 3,922 ​ $ 72,929 ​ $ 111,610 ​ $ 7,304,342 ​ $ 7,415,952 ​
Schedule of non-business individually assessed loans	All loan classes are collectively assessed for impairment except business lending. A summary of individually assessed business lending loans as of December 31, 2021 and 2020 follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ December 31, (000’s omitted) 2021 2020 Loans with allowance allocation ​ $ 7,102 ​ $ 27,437 Loans without allowance allocation ​ 7,417 ​ 8,138 Carrying balance ​ 14,519 ​ 35,575 Contractual balance ​ 16,963 ​ 38,362 Specifically allocated allowance ​ 566 ​ 3,874 ​
Schedule of troubled debt restructurings on financing receivables	Information regarding TDRs as of December 31, 2021 and 2020 is as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2021 December 31, 2020 (000’s omitted) ​ Nonaccrual ​ Accruing ​ Total ​ Nonaccrual ​ Accruing ​ Total ​ # Amount # Amount # Amount # Amount # Amount # Amount Business lending ​ 10 ​ $ 1,011 4 ​ $ 811 14 ​ $ 1,822 6 ​ $ 529 4 ​ $ 191 10 ​ $ 720 Consumer mortgage ​ 61 ​ 2,694 47 ​ 2,420 108 ​ 5,114 56 ​ 2,413 48 ​ 2,266 104 ​ 4,679 Consumer indirect ​ 0 ​ 0 72 ​ 829 72 ​ 829 0 ​ 0 86 ​ 951 86 ​ 951 Consumer direct ​ 0 ​ 0 16 ​ 7 16 ​ 7 0 ​ 0 23 ​ 85 23 ​ 85 Home equity ​ 10 ​ 235 12 ​ 232 22 ​ 467 11 ​ 285 13 ​ 264 24 ​ 549 Total ​ 81 ​ $ 3,940 151 ​ $ 4,299 232 ​ $ 8,239 73 ​ $ 3,227 174 ​ $ 3,757 247 ​ $ 6,984 ​ The following table presents information related to loans modified in a TDR during the years ended December 31, 2021 and 2020. Of the loans noted in the table below, all consumer mortgage loans for the years ended December 31, 2021 and 2020 were modified due to a Chapter 7 bankruptcy as described previously. The financial effects of these restructurings were immaterial. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2021 December 31, 2020 (000’s omitted) # Amount # Amount Business lending ​ 5 ​ $ 1,371 ​ 1 ​ $ 4 Consumer mortgage ​ 24 ​ ​ 1,425 ​ 17 ​ 1,339 Consumer indirect ​ 23 ​ ​ 284 ​ 31 ​ 333 Consumer direct ​ 2 ​ ​ 7 ​ 3 ​ 10 Home equity ​ 0 ​ ​ 0 ​ 3 ​ 70 Total ​ 54 ​ $ 3,087 ​ 55 ​ $ 1,756 ​
Schedule of allowance for loan losses by class	The following presents by segment the activity in the allowance for credit losses during 2021 and 2020: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended December 31, 2021 ​ Beginning Charge- ​ Ending (000’s omitted) ​ balance ​ offs ​ Recoveries ​ Provision ​ balance Business lending ​ $ 28,190 ​ $ (1,618) ​ $ 689 ​ $ (6,240) ​ $ 21,021 Consumer mortgage ​ 10,672 ​ (426) ​ 91 ​ (320) ​ 10,017 Consumer indirect ​ 13,696 ​ (5,160) ​ 4,346 ​ (1,145) ​ 11,737 Consumer direct ​ 3,207 ​ (1,232) ​ 793 ​ (462) ​ 2,306 Home equity ​ 2,222 ​ (225) ​ 92 ​ (275) ​ 1,814 Unallocated ​ 1,000 ​ 0 ​ 0 ​ 0 ​ 1,000 Purchased credit deteriorated ​ 1,882 ​ (304) ​ 107 ​ 289 ​ 1,974 Allowance for credit losses – loans ​ 60,869 ​ (8,965) ​ 6,118 ​ (8,153) ​ 49,869 Liabilities for off-balance-sheet credit exposures ​ 1,489 ​ 0 ​ 0 ​ (686) ​ 803 Total allowance for credit losses ​ $ 62,358 ​ $ (8,965) ​ $ 6,118 ​ $ (8,839) ​ $ 50,672 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended December 31, 2020 ​ ​ Beginning ​ ​ ​ ​ Beginning ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ balance, ​ ​ ​ ​ balance, ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ prior to the ​ ​ ​ ​ after ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ adoption of ​ Impact of ​ adoption of ​ Charge- ​ ​ ​ ​ Steuben ​ ​ ​ ​ Ending (000’s omitted) ​ ASC 326 ASC 326 ASC 326 offs Recoveries acquisition Provision balance Business lending ​ $ 19,426 ​ $ 288 ​ $ 19,714 ​ $ (1,497) ​ $ 356 ​ $ 2,343 ​ $ 7,274 ​ $ 28,190 Consumer mortgage ​ 10,269 ​ (1,051) ​ 9,218 ​ (862) ​ 130 ​ 146 ​ 2,040 ​ 10,672 Consumer indirect ​ 13,712 ​ (997) ​ 12,715 ​ (6,382) ​ 3,992 ​ 183 ​ 3,188 ​ 13,696 Consumer direct ​ 3,255 ​ (643) ​ 2,612 ​ (1,633) ​ 743 ​ 87 ​ 1,398 ​ 3,207 Home equity ​ 2,129 ​ 808 ​ 2,937 ​ (199) ​ 28 ​ 235 ​ (779) ​ 2,222 Unallocated ​ 957 ​ 43 ​ 1,000 ​ 0 ​ 0 ​ 0 ​ 0 ​ 1,000 Purchased credit deteriorated ​ 0 ​ 3,072 ​ 3,072 ​ (91) ​ 440 ​ 668 ​ (2,207) ​ 1,882 Acquired impaired ​ 163 ​ (163) ​ 0 ​ 0 ​ 0 ​ 0 ​ 0 ​ 0 Allowance for credit losses – loans ​ 49,911 ​ 1,357 ​ 51,268 ​ (10,664) ​ 5,689 ​ 3,662 ​ 10,914 ​ 60,869 Liabilities for off-balance-sheet credit exposures ​ 0 ​ 1,185 ​ 1,185 ​ 0 ​ 0 ​ 67 ​ 237 ​ 1,489 Total allowance for credit losses ​ $ 49,911 ​ $ 2,542 ​ $ 52,453 ​ $ (10,664) ​ $ 5,689 ​ $ 3,729 ​ $ 11,151 ​ $ 62,358 ​
Schedule of financing receivables purchased and Sold	The following table presents the carrying amounts of loans purchased and sold during the year ended December 31, 2021 by portfolio segment: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (000’s Business Consumer Consumer Consumer Home ​ omitted) ​ lending ​ mortgage ​ indirect ​ direct ​ equity ​ Total Purchases ​ $ 0 ​ $ 0 ​ $ 0 ​ $ 0 ​ $ 0 ​ $ 0 Sales ​ 3,748 ​ 20,133 ​ 0 ​ 0 ​ 0 ​ 23,881
Business Lending
Loans and Leases Receivable Disclosure [Line Items]
Schedule of loans by credit quality indicator	​ The following tables show the amount of business lending loans by credit quality category at December 31, 2021 and 2020: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Term Loans Amortized Cost Basis by Origination Year ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Revolving ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Loans ​ ​ ​ (000’s omitted) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Amortized ​ ​ ​ December 31, 2021 2021 2020 2019 2018 2017 Prior Cost Basis Total Business lending: ​ ​ ​ ​ ​ ​ ​ ​ Risk rating ​ ​ ​ ​ ​ ​ ​ ​ Pass ​ $ 524,302 ​ $ 328,885 ​ $ 320,638 ​ $ 248,175 ​ $ 186,074 ​ $ 584,912 ​ $ 524,553 ​ $ 2,717,539 Special mention ​ 5,969 ​ 11,013 ​ 10,111 ​ 46,318 ​ 22,524 ​ 57,134 ​ 27,444 ​ 180,513 Classified ​ 1,870 ​ 1,767 ​ 20,315 ​ 40,235 ​ 21,904 ​ 63,685 ​ 27,511 ​ 177,287 Doubtful ​ 0 ​ 0 ​ 0 ​ 62 ​ 0 ​ 0 ​ 503 ​ 565 Total business lending ​ $ 532,141 ​ $ 341,665 ​ $ 351,064 ​ $ 334,790 ​ $ 230,502 ​ $ 705,731 ​ $ 580,011 ​ $ 3,075,904 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Term Loans Amortized Cost Basis by Origination Year ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Revolving ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Loans ​ ​ ​ (000’s omitted) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Amortized ​ ​ ​ December 31, 2020 2020 2019 2018 2017 2016 Prior Cost Basis Total Business lending: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Risk rating ​ ​ ​ ​ ​ ​ ​ ​ ​ Pass ​ $ 860,178 ​ $ 351,350 ​ $ 312,087 ​ $ 217,138 ​ $ 231,453 ​ $ 543,999 ​ $ 483,018 ​ $ 2,999,223 Special mention ​ 14,687 ​ 36,041 ​ 28,410 ​ 21,875 ​ 29,386 ​ 51,657 ​ 52,732 ​ 234,788 Classified ​ 6,336 ​ 4,560 ​ 30,422 ​ 24,807 ​ 14,891 ​ 65,157 ​ 56,000 ​ 202,173 Doubtful ​ 0 ​ 18 ​ 2,888 ​ 0 ​ 0 ​ 108 ​ 879 ​ 3,893 Total business lending ​ $ 881,201 ​ $ 391,969 ​ $ 373,807 ​ $ 263,820 ​ $ 275,730 ​ $ 660,921 ​ $ 592,629 ​ $ 3,440,077 ​
All Other Loans [Member]
Loans and Leases Receivable Disclosure [Line Items]
Schedule of loans by credit quality indicator	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 December 31, 2021 and 2020: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Term Loans Amortized Cost Basis by Origination Year ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Revolving ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Loans ​ ​ ​ (000’s omitted) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Amortized ​ ​ ​ December 31, 2021 2021 2020 2019 2018 2017 Prior Cost Basis Total Consumer mortgage: ​ ​ ​ ​ ​ ​ ​ ​ FICO AB ​ ​ ​ ​ ​ ​ ​ ​ Performing ​ $ 514,680 ​ $ 229,039 ​ $ 183,469 ​ $ 113,618 ​ $ 116,417 ​ $ 566,129 ​ $ 0 ​ $ 1,723,352 Nonperforming ​ 0 ​ 266 ​ 0 ​ 131 ​ 435 ​ 3,236 ​ 0 ​ 4,068 Total FICO AB ​ 514,680 ​ 229,305 ​ 183,469 ​ 113,749 ​ 116,852 ​ 569,365 ​ 0 ​ 1,727,420 FICO CDE ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Performing ​ 168,870 ​ 122,546 ​ 85,253 ​ 57,973 ​ 54,396 ​ 300,341 ​ 25,028 ​ 814,407 Nonperforming ​ 0 ​ 522 ​ 972 ​ 1,465 ​ 939 ​ 10,389 ​ 0 ​ 14,287 Total FICO CDE ​ 168,870 ​ 123,068 ​ 86,225 ​ 59,438 ​ 55,335 ​ 310,730 ​ 25,028 ​ 828,694 Total consumer mortgage ​ $ 683,550 ​ $ 352,373 ​ $ 269,694 ​ $ 173,187 ​ $ 172,187 ​ $ 880,095 ​ $ 25,028 ​ $ 2,556,114 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Consumer indirect: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Performing ​ $ 590,857 ​ $ 204,529 ​ $ 182,458 ​ $ 107,683 ​ $ 39,385 ​ $ 64,750 ​ $ 0 ​ $ 1,189,662 Nonperforming ​ 0 ​ 34 ​ 0 ​ 24 ​ 17 ​ 12 ​ 0 ​ 87 Total consumer indirect ​ $ 590,857 ​ $ 204,563 ​ $ 182,458 ​ $ 107,707 ​ $ 39,402 ​ $ 64,762 ​ $ 0 ​ $ 1,189,749 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Consumer direct: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Performing ​ $ 72,584 ​ $ 28,905 ​ $ 24,770 ​ $ 12,340 ​ $ 4,396 ​ $ 4,575 ​ $ 6,218 ​ $ 153,788 Nonperforming ​ 0 ​ 4 ​ 18 ​ 1 ​ 0 ​ 0 ​ 0 ​ 23 Total consumer direct ​ $ 72,584 ​ $ 28,909 ​ $ 24,788 ​ $ 12,341 ​ $ 4,396 ​ $ 4,575 ​ $ 6,218 ​ $ 153,811 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Home equity: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Performing ​ $ 76,041 ​ $ 43,106 ​ $ 35,990 ​ $ 18,824 ​ $ 15,134 ​ $ 35,740 ​ $ 170,422 ​ $ 395,257 Nonperforming ​ 0 ​ 64 ​ 47 ​ 102 ​ 131 ​ 679 ​ 1,781 ​ 2,804 Total home equity ​ $ 76,041 ​ $ 43,170 ​ $ 36,037 ​ $ 18,926 ​ $ 15,265 ​ $ 36,419 ​ $ 172,203 ​ $ 398,061 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Term Loans Amortized Cost Basis by Origination Year ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Revolving ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Loans ​ ​ ​ (000’s omitted) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Amortized ​ ​ ​ December 31, 2020 2020 2019 2018 2017 2016 Prior Cost Basis Total Consumer mortgage: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ FICO AB ​ ​ ​ ​ ​ ​ ​ ​ Performing ​ $ 260,588 ​ $ 227,027 ​ $ 166,638 ​ $ 163,653 ​ $ 160,911 ​ $ 614,976 ​ $ 321 ​ $ 1,594,114 Nonperforming ​ 0 ​ 0 ​ 275 ​ 398 ​ 345 ​ 2,709 ​ 0 ​ 3,727 Total FICO AB ​ 260,588 ​ 227,027 ​ 166,913 ​ 164,051 ​ 161,256 ​ 617,685 ​ 321 ​ 1,597,841 FICO CDE ​ ​ ​ ​ ​ ​ ​ ​ Performing ​ 115,049 ​ 102,788 ​ 80,973 ​ 75,289 ​ 83,214 ​ 314,668 ​ 17,382 ​ 789,363 Nonperforming ​ 0 ​ 1,010 ​ 582 ​ 877 ​ 1,786 ​ 10,040 ​ 0 ​ 14,295 Total FICO CDE ​ 115,049 ​ 103,798 ​ 81,555 ​ 76,166 ​ 85,000 ​ 324,708 ​ 17,382 ​ 803,658 Total consumer mortgage ​ $ 375,637 ​ $ 330,825 ​ $ 248,468 ​ $ 240,217 ​ $ 246,256 ​ $ 942,393 ​ $ 17,703 ​ $ 2,401,499 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Consumer indirect: ​ ​ ​ ​ ​ ​ ​ ​ Performing ​ $ 303,471 ​ $ 305,901 ​ $ 202,373 ​ $ 86,497 ​ $ 61,449 ​ $ 61,975 ​ $ 0 ​ $ 1,021,666 Nonperforming ​ 51 ​ 52 ​ 82 ​ 17 ​ 16 ​ 1 ​ 0 ​ 219 Total consumer indirect ​ $ 303,522 ​ $ 305,953 ​ $ 202,455 ​ $ 86,514 ​ $ 61,465 ​ $ 61,976 ​ $ 0 ​ $ 1,021,885 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Consumer direct: ​ ​ ​ ​ ​ ​ ​ ​ Performing ​ $ 49,181 ​ $ 46,992 ​ $ 27,872 ​ $ 12,326 ​ $ 5,232 ​ $ 4,146 ​ $ 6,878 ​ $ 152,627 Nonperforming ​ 1 ​ 19 ​ 2 ​ 5 ​ 0 ​ 3 ​ 0 ​ 30 Total consumer direct ​ $ 49,182 ​ $ 47,011 ​ $ 27,874 ​ $ 12,331 ​ $ 5,232 ​ $ 4,149 ​ $ 6,878 ​ $ 152,657 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Home equity: ​ ​ ​ ​ ​ ​ ​ ​ Performing ​ $ 48,145 ​ $ 48,780 ​ $ 28,074 ​ $ 23,524 ​ $ 17,828 ​ $ 35,900 ​ $ 194,773 ​ $ 397,024 Nonperforming ​ 0 ​ 24 ​ 73 ​ 104 ​ 183 ​ 490 ​ 1,936 ​ 2,810 Total home equity ​ $ 48,145 ​ $ 48,804 ​ $ 28,147 ​ $ 23,628 ​ $ 18,011 ​ $ 36,390 ​ $ 196,709 ​ $ 399,834 ​

PREMISES AND EQUIPMENT (Tables)

PREMISES AND EQUIPMENT (Tables)	12 Months Ended
	Dec. 31, 2021
PREMISES AND EQUIPMENT
Schedule of premises and equipment	Premises and equipment consist of the following at December 31: ​ ​ ​ ​ ​ ​ ​ ​ (000’s omitted) 2021 2020 Land and land improvements ​ $ 31,884 ​ $ 29,070 Bank premises ​ 151,724 ​ 149,217 Equipment ​ 85,391 ​ 93,013 Operating lease right-of-use assets ​ 31,754 ​ 34,908 Construction in progress ​ ​ 4,786 ​ ​ 6,226 Premises and equipment, gross ​ 305,539 ​ 312,434 Accumulated depreciation ​ (144,888) ​ (146,779) Premises and equipment, net ​ $ 160,651 ​ $ 165,655

GOODWILL AND IDENTIFIABLE INT_2

GOODWILL AND IDENTIFIABLE INTANGIBLE ASSETS (Tables)	12 Months Ended
	Dec. 31, 2021
GOODWILL AND IDENTIFIABLE INTANGIBLE ASSETS
Schedule of gross carrying amount and accumulated amortization for each type of identifiable intangible asset	The gross carrying amount and accumulated amortization for each type of identifiable intangible asset are as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2021 December 31, 2020 ​ ​ Gross ​ ​ ​ ​ Net ​ Gross ​ ​ ​ ​ Net ​ Carrying Accumulated Carrying Carrying Accumulated Carrying (000’s omitted) ​ Amount Amortization Amount Amount Amortization Amount Amortizing intangible assets: ​ ​ ​ ​ ​ ​ ​ Core deposit intangibles ​ $ 69,403 ​ $ (60,316) ​ $ 9,087 ​ $ 69,403 ​ $ (55,572) ​ $ 13,831 Other intangibles ​ 116,799 ​ (60,660) ​ 56,139 ​ 90,462 ​ (51,353) ​ 39,109 Total amortizing intangibles ​ $ 186,202 ​ $ (120,976) ​ $ 65,226 ​ $ 159,865 ​ $ (106,925) ​ $ 52,940 ​
Schedule of 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): ​ ​ ​ ​ ​ Year Amount 2022 ​ $ 13,668 2023 ​ ​ 11,595 2024 ​ 9,782 2025 ​ 8,349 2026 ​ 7,494 Thereafter ​ 14,338 Total ​ $ 65,226 ​
Schedule of components of goodwill	Shown below are the components of the Company’s goodwill at December 31, 2021, 2020, and 2019: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ ​ ​ ​ December 31, ​ ​ ​ ​ December 31, (000’s omitted) ​ 2019 Activity 2020 Activity 2021 Goodwill, net ​ $ 773,810 ​ $ 19,898 ​ $ 793,708 ​ $ 5,401 ​ $ 799,109 ​
Schedule of changes in carrying value of MSRs and associated valuation allowance	The following table summarizes the changes in carrying value of MSRs and the associated valuation allowance: ​ ​ ​ ​ ​ ​ ​ ​ (000’s omitted) ​ 2021 ​ 2020 Carrying value before valuation allowance at beginning of period ​ $ 1,430 ​ $ 972 Additions ​ 233 ​ 715 Acquisitions ​ 0 ​ 122 Amortization ​ (519) ​ (379) Carrying value before valuation allowance at end of period ​ 1,144 ​ 1,430 Valuation allowance balance at beginning of period ​ (219) ​ (298) Impairment charges ​ (55) ​ (150) Impairment recoveries ​ 274 ​ 229 Valuation allowance balance at end of period ​ 0 ​ (219) Net carrying value at end of period ​ $ 1,144 ​ $ 1,211 Fair value of MSRs at end of period ​ $ 1,469 ​ $ 1,384 Principal balance of mortgage loans sold during the year ​ $ 20,133 ​ $ 79,709 Principal balance of loans serviced for others ​ $ 296,506 ​ $ 351,759 Custodial escrow balances maintained in connection with loans serviced for others ​ $ 4,934 ​ $ 5,583 ​
Schedule of key economic assumptions used to estimate value of MSRs	The following table summarizes the key economic assumptions used to estimate the value of the MSRs at December 31: ​ ​ ​ ​ ​ ​ ​ ​ ​ 2021 ​ 2020 Weighted-average contractual life (in years) 21.4 21.5 ​ Weighted-average constant prepayment rate (CPR) 24.5 % 30.4 % Weighted-average discount rate 2.6 % 2.1 %

DEPOSITS (Tables)

DEPOSITS (Tables)	12 Months Ended
	Dec. 31, 2021
DEPOSITS.
Schedule of deposits	Deposits recorded in the consolidated statements of condition consist of the following at December 31: ​ ​ ​ ​ ​ ​ ​ ​ (000’s omitted) ​ 2021 ​ 2020 Noninterest checking ​ $ 3,921,663 ​ $ 3,361,768 Interest checking ​ 3,201,225 ​ 2,876,420 Savings ​ 2,255,961 ​ 1,949,517 Money market ​ 2,603,988 ​ 2,103,498 Time ​ 928,331 ​ 933,771 Total deposits ​ $ 12,911,168 ​ $ 11,224,974 ​
Schedule of interest on deposits	Interest on deposits recorded in the consolidated statements of income consists of the following at December 31: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (000’s omitted) ​ 2021 ​ 2020 ​ 2019 Interest on interest checking ​ $ 1,142 ​ $ 2,182 ​ $ 3,678 Interest on savings ​ 598 ​ 665 ​ 942 Interest on money market ​ 1,393 ​ 2,685 ​ 5,836 Interest on time ​ 8,498 ​ 11,229 ​ 10,004 Total interest on deposits ​ $ 11,631 ​ $ 16,761 ​ $ 20,460 ​
Schedule of maturities of time deposits	The approximate maturities of time deposits at December 31, 2021 are as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Accounts $250,000 (000’s omitted) ​ All Accounts ​ or Greater 2022 ​ $ 579,595 ​ $ 186,647 2023 ​ 139,881 ​ 7,408 2024 ​ 162,317 ​ 38,681 2025 ​ 21,494 ​ 2,102 2026 ​ 25,010 ​ 1,922 Thereafter ​ 34 ​ 0 Total ​ $ 928,331 ​ $ 236,760

BORROWINGS (Tables)

BORROWINGS (Tables)	12 Months Ended
	Dec. 31, 2021
BORROWINGS
Schedule of outstanding borrowings	Outstanding borrowings at December 31 are as follows: ​ ​ ​ ​ ​ ​ ​ ​ (000’s omitted) ​ 2021 ​ 2020 Subordinated notes payable, includes premium of $277 and $303, respectively ​ $ 3,277 ​ $ 3,303 Subordinated debt held by unconsolidated subsidiary trusts ​ 0 ​ 77,320 Securities sold under agreement to repurchase, short term ​ 324,720 ​ 284,008 Other FHLB borrowings ​ 1,888 ​ 6,658 Total borrowings ​ $ 329,885 ​ $ 371,289 ​
Schedule of borrowings by contractual maturity dates	Borrowings at December 31, 2021 have contractual maturity dates as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted-average ​ ​ Carrying ​ Rate at (000’s omitted, except rate) ​ Value ​ December 31, 2021 January 2, 2022 ​ $ 324,720 0.27 % February 8, 2023 ​ 190 1.79 % July 3, 2023 ​ 497 2.25 % October 23, 2023 ​ 395 1.50 % October 1, 2025 ​ 275 1.50 % February 28, 2028 ​ 3,277 4.67 % March 1, 2029 ​ 531 2.50 % Total ​ $ 329,885 0.32 % ​

INCOME TAXES (Tables)

INCOME TAXES (Tables)	12 Months Ended
	Dec. 31, 2021
INCOME TAXES
Schedule of provision for income taxes	The provision for income taxes for the years ended December 31 is as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (000’s omitted) 2021 2020 2019 Current: ​ ​ ​ Federal ​ $ 35,507 ​ $ 35,728 ​ $ 34,804 State and other ​ 8,158 ​ 8,008 ​ 7,773 Deferred: ​ ​ ​ ​ Federal ​ 5,493 ​ (2,005) ​ (699) State and other ​ 2,496 ​ (331) ​ (1,603) Provision for income taxes ​ $ 51,654 ​ $ 41,400 ​ $ 40,275 ​
Schedule of net deferred tax liability	Components of the net deferred tax liability, included in other liabilities, as of December 31 are as follows: ​ ​ ​ ​ ​ ​ ​ ​ (000’s omitted) 2021 2020 Allowance for credit losses ​ $ 12,435 ​ $ 15,004 Employee benefits ​ 7,708 ​ 7,552 Operating lease liabilities ​ 7,955 ​ 8,601 Other, net ​ 1,250 ​ 900 Deferred tax asset ​ 29,348 ​ 32,057 ​ ​ ​ ​ ​ ​ ​ Investment securities ​ 7,227 ​ 43,325 Goodwill and intangibles ​ 41,917 ​ 40,802 Operating lease right-of-use assets ​ 7,693 ​ 8,384 Loan origination costs ​ 8,993 ​ 7,904 Depreciation ​ 535 ​ 3,089 Mortgage servicing rights ​ 278 ​ 291 Pension ​ 22,950 ​ 16,987 Deferred tax liability ​ 89,593 ​ 120,782 Net deferred tax liability ​ $ (60,245) ​ $ (88,725) ​
Schedule of reconciliation of the differences between the federal statutory income tax rate	A reconciliation of the differences between the federal statutory income tax rate and the effective tax rate for the years ended December 31 is shown in the following table: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2021 2020 2019 Federal statutory income tax rate 21.0 % 21.0 % 21.0 % Increase (reduction) in taxes resulting from: ​ ​ Tax-exempt interest (1.1) (1.5) (1.5) ​ State income taxes, net of federal benefit 3.6 3.0 2.5 ​ Stock-based compensation (0.9) (0.8) (1.6) ​ Federal tax credits (1.0) (1.3) (1.3) ​ Other, net (0.2) (0.3) 0.1 ​ Effective income tax rate 21.4 % 20.1 % 19.2 %

BENEFIT PLANS (Tables)

BENEFIT PLANS (Tables)	12 Months Ended
	Dec. 31, 2021
BENEFIT PLANS
Schedule of funded status of the Company???s plans reconciled with amounts reported	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Pension Benefits ​ Post-retirement Benefits (000’s omitted) 2021 2020 2021 2020 Change in benefit obligation: ​ ​ ​ ​ Benefit obligation at the beginning of year ​ $ 190,361 ​ $ 162,084 ​ $ 1,718 ​ $ 1,677 Service cost ​ 5,920 ​ 5,750 ​ 0 ​ 0 Interest cost ​ 5,036 ​ 5,657 ​ 44 ​ 57 Plan amendment / acquisition ​ 0 ​ 13,598 ​ 0 ​ 0 Participant contributions ​ 0 ​ 0 ​ 0 ​ 0 Deferred actuarial (gain)/loss ​ (4,881) ​ 13,954 ​ (85) ​ 114 Benefits paid ​ (13,166) ​ (10,682) ​ (148) ​ (130) Benefit obligation at end of year ​ 183,270 ​ 190,361 ​ 1,529 ​ 1,718 Change in plan assets: ​ ​ ​ ​ ​ ​ ​ ​ Fair value of plan assets at beginning of year ​ 272,600 ​ 227,323 ​ 0 ​ 0 Actual return of plan assets ​ 27,614 ​ 33,543 ​ 0 ​ 0 Participant contributions ​ 0 ​ 0 ​ 0 ​ 0 Employer contributions ​ 3,639 ​ 7,993 ​ 148 ​ 130 Plan acquisition ​ 0 ​ 14,423 ​ 0 ​ 0 Benefits paid ​ (13,166) ​ (10,682) ​ (148) ​ (130) Fair value of plan assets at end of year ​ 290,687 ​ 272,600 ​ 0 ​ 0 Over/(Under) funded status at year end ​ $ 107,417 ​ $ 82,239 ​ $ (1,529) ​ $ (1,718) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Amounts recognized in the consolidated statement of condition were: ​ ​ ​ ​ Other assets ​ $ 127,538 ​ $ 101,849 ​ $ 0 ​ $ 0 Other liabilities ​ (20,121) ​ (19,610) ​ (1,529) ​ (1,718) Amounts recognized in accumulated other comprehensive loss/(income) (“AOCI”) were: ​ ​ ​ ​ Net loss ​ $ 16,977 ​ $ 34,290 ​ $ 585 ​ $ 715 Net prior service cost (credit) ​ 3,969 ​ 4,348 ​ (907) ​ (1,086) Pre-tax AOCI ​ 20,946 ​ 38,638 ​ (322) ​ (371) Taxes ​ (5,236) ​ (9,488) ​ 82 ​ 94 AOCI at year end ​ $ 15,710 ​ $ 29,150 ​ $ (240) ​ $ (277)
Schedule of Amounts recognized in accumulated other comprehensive income, net of tax	Amounts recognized in accumulated other comprehensive income, net of tax, for the year ended December 31, are as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Pension Benefits ​ Post-retirement Benefits (000’s omitted) 2021 2020 2021 2020 Prior service cost/(credit) ​ $ (288) ​ $ 222 ​ $ 136 ​ $ 136 Net (gain) loss ​ (13,152) ​ (6,423) ​ (99) ​ 56 Total ​ $ (13,440) ​ $ (6,201) ​ $ 37 ​ $ 192 ​
Schedule of weighted-average assumptions used to determine the benefit obligations	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Pension Benefits ​ Post-retirement Benefits ​ 2021 2020 2021 2020 Discount rate 3.10 % 2.80 % 3.10 % 2.80 % Expected return on plan assets 6.70 % 7.00 % N/A N/A ​ Rate of compensation increase ​ 4.00% for 2022 ​ 3.50 % N/A ​ N/A ​ ​ 3.50% for 2023 + ​ ​ ​ ​ ​ Interest crediting rates ​ 6.00% while employed, ​ 6.00% while employed, ​ N/A ​ N/A ​ ​ ​ 1.94% after termination ​ 1.42% after termination ​ ​ ​ ​ ​ ​
Schedule of net periodic benefit cost	The net periodic benefit cost as of December 31 is as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Pension Benefits ​ Post-retirement Benefits (000’s omitted) 2021 2020 2019 2021 2020 2019 Service cost ​ $ 5,920 ​ $ 5,750 ​ $ 5,081 ​ $ 0 ​ $ 0 ​ $ 0 Interest cost ​ 5,036 ​ 5,657 ​ 6,264 ​ 44 ​ 57 ​ 70 Expected return on plan assets ​ (18,783) ​ (16,306) ​ (14,311) ​ 0 ​ 0 ​ 0 Plan amendment ​ 0 ​ (637) ​ 0 ​ 0 ​ 0 ​ 0 Amortization of unrecognized net loss ​ 3,600 ​ 3,239 ​ 2,568 ​ 45 ​ 40 ​ 38 Amortization of prior service cost ​ 379 ​ 241 ​ 64 ​ (179) ​ (179) ​ (179) Net periodic (benefit) ​ $ (3,848) ​ $ 2,056 ​ $ (334) ​ $ (90) ​ $ (82) ​ $ (71) ​
Schedule of weighted-average assumptions used to determine the net periodic pension cost	The weighted-average assumptions used to determine the net periodic pension cost for the years ended December 31 are as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Pension Benefits ​ Post-retirement Benefits ​ 2021 2020 2019 2021 2020 2019 Discount rate 2.80 % 3.50 % 4.50 % 2.80 % 3.60 % 4.45 % Expected return on plan assets 7.00 % 7.00 % 7.00 % N/A N/A N/A ​ Rate of compensation increase 3.50 % 3.50 % 3.50 % N/A N/A N/A ​ Interest crediting rates ​ 6.00% while employed, ​ 6.00% while employed ​ 6.00% while employed ​ N/A ​ N/A ​ N/A ​ ​ ​ 1.42% after termination ​ 2.16% after termination ​ 3.15% after termination ​ ​ ​ ​ ​ ​ ​
Schedule of amount of benefit payments	The amount of benefit payments that are expected to be paid over the next ten years are as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Pension ​ ​ Post-retirement (000’s omitted) ​ Benefits ​ Benefits 2022 ​ $ 10,940 ​ $ 151 2023 ​ 11,863 ​ 119 2024 ​ 12,185 ​ 117 2025 ​ 11,991 ​ 115 2026 ​ 13,567 ​ 113 2027-2031 ​ 63,874 ​ 522 ​
Schedule of fair value of defined benefit plan assets by asset category	The fair values of the Company’s defined benefit pension plan assets at December 31, 2021 by asset category are as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Quoted Prices ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ in Active ​ Significant ​ Significant ​ ​ ​ ​ Markets for ​ Observable ​ Unobservable ​ ​ ​ ​ Identical Assets ​ Inputs ​ Inputs ​ ​ Asset category (000’s omitted) Level 1 Level 2 Level 3 Total Cash equivalents ​ $ 19,605 ​ $ 0 ​ $ 0 ​ $ 19,605 Equity securities: ​ ​ ​ ​ ​ ​ ​ U.S. large-cap ​ 75,180 ​ 0 ​ 0 ​ 75,180 U.S mid/small cap ​ 12,052 ​ 0 ​ 0 ​ 12,052 CBU common stock ​ 7,604 ​ 0 ​ 0 ​ 7,604 International ​ 73,891 ​ 0 ​ 0 ​ 73,891 Other ​ 1,091 ​ 0 ​ 0 ​ 1,091 ​ ​ 169,818 ​ 0 ​ 0 ​ 169,818 ​ ​ ​ ​ ​ ​ ​ ​ Fixed income securities: ​ ​ ​ ​ ​ ​ ​ Government securities ​ 19,988 ​ 5,974 ​ 0 ​ 25,962 Investment grade bonds ​ 41,374 ​ 136 ​ 0 ​ 41,510 High yield (a) ​ 8,625 ​ 0 ​ 0 ​ 8,625 ​ ​ 69,987 ​ 6,110 ​ 0 ​ 76,097 ​ ​ ​ ​ ​ ​ ​ ​ Other investments (b) ​ 24,727 ​ 0 ​ 0 ​ 24,727 ​ ​ ​ ​ ​ ​ ​ ​ Total (c) ​ $ 284,137 ​ $ 6,110 ​ $ 0 ​ $ 290,247 ​ The fair values of the Company’s defined benefit pension plan assets at December 31, 2020 by asset category are as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Quoted Prices ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ in Active ​ Significant ​ Significant ​ ​ ​ ​ ​ Markets for ​ Observable ​ Unobservable ​ ​ ​ ​ ​ Identical Assets ​ Inputs ​ Inputs ​ ​ ​ Asset category (000’s omitted) Level 1 Level 2 Level 3 Total Cash equivalents ​ $ 68,137 ​ $ 0 ​ $ 0 ​ $ 68,137 Equity securities: ​ ​ ​ ​ ​ ​ ​ U.S. large-cap ​ 69,195 ​ 0 ​ 0 ​ 69,195 U.S mid/small cap ​ 17,338 ​ 0 ​ 0 ​ 17,338 CBU common stock ​ 7,701 ​ 0 ​ 0 ​ 7,701 International ​ 43,457 ​ 6,088 ​ 0 ​ 49,545 ​ ​ 137,691 ​ 6,088 ​ 0 ​ 143,779 ​ ​ ​ ​ ​ ​ ​ ​ Fixed income securities: ​ ​ ​ ​ ​ ​ ​ Government securities ​ 6,154 ​ 6,241 ​ 0 ​ 12,395 Investment grade bonds ​ 23,085 ​ 141 ​ 0 ​ 23,226 High yield (a) ​ 5,803 ​ 0 ​ 0 ​ 5,803 ​ ​ 35,042 ​ 6,382 ​ 0 ​ 41,424 ​ ​ ​ ​ ​ ​ ​ ​ Other investments (b) ​ 17,613 ​ 0 ​ 0 ​ 17,613 ​ ​ ​ ​ ​ ​ ​ ​ Total (c)(d) ​ $ 258,483 ​ $ 12,470 ​ $ 0 ​ $ 270,953 ​ (a) This category is exchange-traded funds representing a diversified index of high yield corporate bonds. (b) This category is comprised of exchange-traded funds and mutual funds holding non-traditional investment classes including private equity funds and alternative exchange funds. (c) Excludes dividends and interest receivable totaling $0.4 million and $0.2 million at December 31, 2021 and 2020, respectively. (d) Excludes certain investments that were measured at net asset value per share (or its equivalents) totaling $1.4 million at December 31, 2020.

STOCK-BASED COMPENSATION PLANS

STOCK-BASED COMPENSATION PLANS (Tables)	12 Months Ended
	Dec. 31, 2021
STOCK-BASED COMPENSATION PLANS
Schedule of Activity in this long-term incentive program	Activity in this long-term incentive program is as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ Stock Options ​ ​ ​ ​ Weighted- ​ ​ ​ ​ average Exercise ​ Outstanding Price of Shares Outstanding at December 31, 2019 1,502,994 ​ $ 42.82 Granted 254,496 ​ 51.68 Exercised (197,564) ​ 32.65 Forfeited (17,667) ​ 50.97 Outstanding at December 31, 2020 1,542,259 ​ 45.49 Granted 168,976 ​ 79.68 Exercised (310,423) ​ 40.17 Forfeited (8,107) ​ 61.56 Outstanding at December 31, 2021 1,392,705 ​ 50.73 Exercisable at December 31, 2021 879,074 ​ $ 43.84 ​
Schedule of information about stock options outstanding under the Company???s stock option plan	The following table summarizes the information about stock options outstanding under the Company’s stock option plan at December 31, 2021: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Options outstanding ​ Options exercisable ​ ​ ​ ​ Weighted- ​ Weighted- ​ ​ ​ Weighted- ​ ​ ​ ​ average ​ average ​ ​ ​ average ​ ​ ​ ​ Exercise ​ Remaining ​ ​ ​ Exercise Range of Exercise Price Shares Price Life (years) Shares Price $0.00 – $29.00 57,354 ​ $ 24.78 3.55 57,354 ​ $ 24.78 $29.01 – $30.00 58,276 ​ 29.79 1.21 58,276 ​ 29.79 $30.01 – $40.00 403,901 ​ 37.07 3.46 403,901 ​ 37.07 $40.01 – $60.00 706,389 ​ 55.54 6.91 352,515 ​ 56.30 $60.01 – $80.00 166,785 ​ 79.68 9.22 7,028 ​ 79.66 TOTAL 1,392,705 ​ $ 50.73 5.81 879,074 ​ $ 43.84 ​
Schedule of valuation assumptions used to estimate value of stock options	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2021 2020 2019 Weighted-average Fair Value of Options Granted ​ $ 18.43 ​ $ 10.86 ​ $ 14.16 ​ Assumptions: ​ ​ ​ ​ ​ Weighted-average expected life (in years) ​ 6.50 ​ 6.50 ​ 6.50 ​ Future dividend yield ​ 2.48 % 2.57 % 2.73 % Share price volatility ​ 30.09 % 29.29 % 29.31 % Weighted-average risk-free interest rate ​ 1.28 % 0.67 % 2.44 % ​
Schedule of activity unvested restricted stock awards	A summary of the status of the Company’s unvested restricted stock awards as of December 31, 2021, and changes during the twelve months ended December 31, 2021 and 2020, is presented below: ​ ​ ​ ​ ​ ​ ​ ​ ​ Restricted ​ Weighted-average ​ Shares grant date fair value Unvested at December 31, 2019 196,788 ​ $ 45.58 Awards 52,132 ​ 51.64 Forfeitures (12,884) ​ 37.14 Vestings (59,628) ​ 47.80 Unvested at December 31, 2020 176,408 ​ 47.24 Awards 51,456 ​ 79.51 Forfeitures (2,619) ​ 54.15 Vestings (47,977) ​ 52.84 Unvested at December 31, 2021 177,268 ​ $ 54.98 ​

EARNINGS PER SHARE (Tables)

EARNINGS PER SHARE (Tables)	12 Months Ended
	Dec. 31, 2021
EARNINGS PER SHARE
Schedule of reconciliation of basic to diluted earnings per share	The following is a reconciliation of basic to diluted earnings per share for the years ended December 31, 2021, 2020 and 2019. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (000’s omitted, except per share data) 2021 2020 2019 Net income ​ $ 189,694 ​ $ 164,676 ​ $ 169,063 Income attributable to unvested stock-based compensation awards ​ (445) ​ (514) ​ (400) Income available to common shareholders ​ $ 189,249 ​ $ 164,162 ​ $ 168,663 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted-average common shares outstanding – basic ​ 53,977 ​ 52,969 ​ 51,732 Basic earnings per share ​ $ 3.51 ​ $ 3.10 ​ $ 3.26 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net income ​ $ 189,694 ​ $ 164,676 ​ $ 169,063 Income attributable to unvested stock-based compensation awards ​ (445) ​ (514) ​ (400) Income available to common shareholders ​ $ 189,249 ​ $ 164,162 ​ $ 168,663 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted-average common shares outstanding ​ 53,977 ​ 52,969 ​ 51,732 Assumed exercise of stock options ​ 423 ​ 352 ​ 516 Weighted-average common shares outstanding – diluted ​ 54,400 ​ 53,321 ​ 52,248 Diluted earnings per share ​ $ 3.48 ​ $ 3.08 ​ $ 3.23 Cash dividends declared per share ​ $ 1.70 ​ $ 1.66 ​ $ 1.58 ​

COMMITMENTS, CONTINGENT LIABI_2

COMMITMENTS, CONTINGENT LIABILITIES AND RESTRICTIONS (Tables)	12 Months Ended
	Dec. 31, 2021
COMMITMENTS, CONTINGENT LIABILITIES AND RESTRICTIONS
Schedule of The contract amounts of commitments and contingencies	The contract amounts of commitments and contingencies are as follows at December 31: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (000’s omitted) 2021 2020 Commitments to extend credit ​ $ 1,443,879 ​ $ 1,313,568 Standby letters of credit ​ 42,684 ​ 39,213 Total ​ $ 1,486,563 ​ $ 1,352,781

LEASES (Tables)

LEASES (Tables)	12 Months Ended
	Dec. 31, 2021
Operating Leases
Schedule of components of lease	The components of lease expense are as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (000’s omitted) 2021 ​ 2020 ​ 2019 Operating lease cost ​ $ 8,397 ​ $ 9,000 ​ $ 8,724 Variable lease cost ​ 50 ​ ​ 53 ​ ​ 18 Short-term lease cost (1) ​ 148 ​ ​ 369 ​ ​ 240 Total lease cost ​ $ 8,595 ​ $ 9,422 ​ $ 8,982 ​ (1) Short-term lease cost includes the cost of leases with terms of twelve months or less, excluding leases with terms of one month or less.
Schedule of supplemental Cash Flow Information Related to Leases	Supplemental cash flow information related to leases is as follows: ​ ​ ​ ​ ​ ​ ​ ​ (000’s omitted) 2021 2020 Cash paid for amounts included in the measurement of lease liabilities: ​ ​ ​ ​ Operating cash outflows for operating leases ​ $ 8,203 ​ $ 8,478 ​ ​ ​ ​ ​ ​ ​ Right-of-use assets obtained in exchange for lease obligations: ​ ​ ​ ​ ​ Operating leases ​ 5,344 ​ ​ 3,519 ​
Schedule of supplemental Balance Sheet Information Related to Leases	Supplemental balance sheet information related to leases is as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ (000’s omitted, except lease term and discount rate) 2021 2020 ​ Operating leases ​ ​ ​ ​ ​ Operating lease right-of-use assets ​ $ 31,754 ​ $ 34,908 ​ ​ ​ ​ ​ ​ ​ ​ ​ Operating lease liabilities ​ 32,833 ​ ​ 35,857 ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted average remaining lease term ​ ​ ​ ​ ​ ​ Operating leases ​ 5.4 years ​ ​ 6.1 years ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted average discount rate ​ ​ ​ ​ ​ ​ Operating leases ​ 2.62 % ​ 2.82 % ​
Schedule of maturities of Lease Liabilities	Maturities of lease liabilities as of December 31, 2021 are as follows: ​ ​ ​ ​ ​ (000’s omitted) Operating Leases 2022 ​ $ 8,729 2023 ​ 7,640 2024 ​ 5,920 2025 ​ 4,401 2026 ​ 3,062 Thereafter ​ 5,846 Total lease payments ​ 35,598 Less imputed interest ​ (2,765) Total ​ $ 32,833 ​ Maturities of lease liabilities as of December 31, 2020 are as follows: ​ ​ ​ ​ ​ (000’s omitted) Operating Leases 2021 ​ $ 8,697 2022 ​ 7,505 2023 ​ 6,336 2024 ​ 4,973 2025 ​ 3,688 Thereafter ​ 8,222 Total lease payments ​ 39,421 Less imputed interest ​ (3,564) Total ​ $ 35,857 ​
706 North Clinton [Member]
Operating Leases
Schedule of maturities of Lease Liabilities	The maturities of the Company’s related party lease liabilities as of December 31, 2021 are as follows: ​ ​ ​ ​ ​ (000’s omitted) 706 North Clinton, LLC 2022 ​ $ 591 2023 ​ 591 2024 ​ 591 2025 ​ 605 2026 ​ 614 Thereafter ​ 1,727 Total lease payments ​ 4,719 Less imputed interest ​ (633) Total ​ $ 4,086 ​ The maturities of the Company’s related party lease liabilities as of December 31, 2020 are as follows: ​ ​ ​ ​ ​ (000’s omitted) ​ 706 North Clinton, LLC 2021 $ 591 2022 ​ 591 2023 ​ ​ 591 2024 ​ ​ 591 2025 ​ 605 Thereafter ​ 2,341 Total lease payments ​ 5,310 Less imputed interest ​ (791) Total ​ $ 4,519

REGULATORY MATTERS (Tables)

REGULATORY MATTERS (Tables)	12 Months Ended
	Dec. 31, 2021
REGULATORY MATTERS
Schedule of capital ratios and amounts	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For capital adequacy ​ To be well-capitalized ​ ​ ​ ​ ​ ​ ​ For capital adequacy ​ purposes plus Capital ​ under prompt ​ ​ Actual ​ purposes ​ Conservation Buffer ​ corrective action (000’s omitted) Amount Ratio Amount Ratio Amount Ratio Amount Ratio Community Bank System, Inc.: ​ ​ ​ ​ ​ 2021 ​ ​ ​ ​ ​ Tier 1 Leverage ratio ​ $ 1,331,368 9.09 % $ 585,594 4.00 % ​ ​ ​ ​ $ 731,993 5.00 % Tier 1 risk-based capital ​ 1,331,368 18.60 % 429,559 6.00 % $ 608,542 8.50 % ​ 572,746 8.00 % Total risk-based capital ​ 1,380,458 19.28 % 572,746 8.00 % 751,729 10.50 % ​ 715,932 10.00 % Common equity tier 1 capital ​ 1,331,259 18.60 % 322,169 4.50 % 501,152 7.00 % ​ 465,356 6.50 % 2020 ​ ​ ​ ​ ​ ​ ​ ​ ​ Tier 1 Leverage ratio ​ $ 1,314,864 10.16 % $ 517,736 4.00 % ​ ​ ​ ​ $ 647,169 5.00 % Tier 1 risk-based capital ​ 1,314,864 18.99 % 415,472 6.00 % $ 588,585 8.50 % ​ 553,962 8.00 % Total risk-based capital ​ 1,375,704 19.87 % 553,962 8.00 % 727,075 10.50 % ​ 692,453 10.00 % Common equity tier 1 capital ​ 1,239,754 17.90 % 311,604 4.50 % 484,717 7.00 % ​ 450,094 6.50 % ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Community Bank, N.A.: ​ ​ ​ ​ ​ 2021 ​ ​ ​ ​ ​ Tier 1 Leverage ratio ​ $ 1,058,091 7.26 % $ 582,631 4.00 % ​ ​ ​ ​ $ 728,289 5.00 % Tier 1 risk-based capital ​ 1,058,091 14.92 % 425,393 6.00 % $ 602,640 8.50 % ​ 567,190 8.00 % Total risk-based capital ​ 1,107,181 15.62 % 567,190 8.00 % 744,437 10.50 % ​ 708,988 10.00 % Common equity tier 1 capital ​ 1,057,982 14.92 % 319,045 4.50 % 496,292 7.00 % ​ 460,842 6.50 % 2020 ​ ​ ​ ​ ​ ​ ​ ​ Tier 1 Leverage ratio ​ $ 1,028,285 7.98 % $ 515,552 4.00 % ​ ​ ​ ​ $ 644,440 5.00 % Tier 1 risk-based capital ​ 1,028,285 14.98 % 411,880 6.00 % $ 583,497 8.50 % ​ 549,174 8.00 % Total risk-based capital ​ 1,089,125 15.87 % 549,174 8.00 % 720,791 10.50 % ​ 686,467 10.00 % Common equity tier 1 capital ​ 1,028,175 14.98 % 308,910 4.50 % 480,527 7.00 % ​ 446,204 6.50 %

PARENT COMPANY STATEMENTS (Tabl

PARENT COMPANY STATEMENTS (Tables)	12 Months Ended
	Dec. 31, 2021
PARENT COMPANY STATEMENTS
Condensed Statements of Condition of Parent Company	The condensed statements of condition of the parent company, Community Bank System, Inc., at December 31 are as follows: ​ ​ ​ ​ ​ ​ ​ ​ (000's omitted) 2021 2020 Assets: ​ ​ Cash and cash equivalents ​ $ 154,374 ​ $ 196,021 Investment securities ​ 8,679 ​ 6,043 Investment in and advances to: ​ ​ ​ Bank subsidiary ​ 1,721,520 ​ 1,802,150 Non-bank subsidiaries ​ 232,096 ​ 196,090 Other assets ​ 18,462 ​ 15,290 Total assets ​ $ 2,135,131 ​ $ 2,215,594 ​ ​ ​ ​ ​ ​ ​ Liabilities and shareholders' equity: ​ ​ ​ Accrued interest and other liabilities ​ $ 31,047 ​ $ 30,864 Borrowings ​ 3,277 ​ 80,623 Shareholders' equity ​ 2,100,807 ​ 2,104,107 Total liabilities and shareholders' equity ​ $ 2,135,131 ​ $ 2,215,594 ​
Condensed Statements of Income of Parent Company	The condensed statements of income of the parent company for the years ended December 31 is as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (000's omitted) 2021 2020 2019 Revenues: ​ ​ ​ Dividends from subsidiaries: ​ ​ ​ Bank subsidiary ​ $ 125,000 ​ $ 105,000 ​ $ 115,000 Non-bank subsidiaries ​ 14,000 ​ 13,500 ​ 27,600 Interest and dividends on investments ​ 245 ​ 168 ​ 134 Total revenues ​ 139,245 ​ 118,668 ​ 142,734 Expenses: ​ ​ ​ ​ ​ ​ Interest on borrowings ​ 446 ​ 2,546 ​ 4,244 Acquisition expenses ​ 0 ​ 450 ​ 1,248 Gain on debt extinguishment ​ 0 ​ (421) ​ 0 Other expenses ​ 5,717 ​ 4,945 ​ 477 Total expenses ​ 6,163 ​ 7,520 ​ 5,969 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Income before tax benefit and equity in undistributed net income of subsidiaries ​ 133,082 ​ 111,148 ​ 136,765 Income tax benefit ​ 3,964 ​ 3,739 ​ 4,545 Income before equity in undistributed net income of subsidiaries ​ 137,046 ​ 114,887 ​ 141,310 Equity in undistributed net income of subsidiaries ​ 52,648 ​ 49,789 ​ 27,753 Net income ​ $ 189,694 ​ $ 164,676 ​ $ 169,063 Other comprehensive (loss) income, net of tax: ​ ​ ​ ​ ​ ​ Changes in other comprehensive income (loss) related to pension and other post retirement obligations ​ 13,403 ​ 6,009 ​ (2,045) Changes in other comprehensive (loss) income related to unrealized (losses) gains on available-for-sale securities ​ (126,107) ​ 66,294 ​ 37,124 Other comprehensive (loss) income ​ (112,704) ​ 72,303 ​ 35,079 Comprehensive income ​ $ 76,990 ​ $ 236,979 ​ $ 204,142 ​
Statements of Cash Flows of Parent Company	The statements of cash flows of the parent company for the years ended December 31 is as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (000's omitted) 2021 2020 2019 Operating activities: ​ ​ ​ Net income ​ $ 189,694 ​ $ 164,676 ​ $ 169,063 Adjustments to reconcile net income to net cash provided by operating activities ​ ​ ​ ​ ​ ​ Equity in undistributed net income of subsidiaries ​ (52,648) ​ (49,789) ​ (27,753) Net change in other assets and other liabilities ​ (3,050) ​ 1,740 ​ 86 Net cash provided by operating activities ​ 133,996 ​ 116,627 ​ 141,396 Investing activities: ​ ​ ​ ​ ​ ​ Purchases of investment securities ​ ​ (5,173) ​ ​ (3,000) ​ ​ 0 Cash paid for acquisitions, net of cash acquired of $0, $448, and $1,328, respectively ​ 0 ​ (20,892) ​ (92,056) (Capital contributions to)/Return of capital from ​ (12,918) ​ 2 ​ 100,680 Net cash (used in)/provided by investing activities ​ (18,091) ​ (23,890) ​ 8,624 Financing activities: ​ ​ ​ ​ ​ ​ Repayment of advances from subsidiaries ​ (482) ​ (482) ​ (1,652) Repayment of borrowings ​ (77,320) ​ (12,062) ​ (22,681) Issuance of common stock ​ 16,155 ​ 22,211 ​ 12,200 Purchase of treasury stock ​ (5,106) ​ (271) ​ (286) Sale of treasury stock ​ 0 ​ 85 ​ 6,884 Increase in deferred compensation arrangements ​ 252 ​ 271 ​ 286 Cash dividends paid ​ (91,051) ​ (87,131) ​ (80,241) Net cash used in financing activities ​ (157,552) ​ (77,379) ​ (85,490) Change in cash and cash equivalents ​ (41,647) ​ 15,358 ​ 64,530 Cash and cash equivalents at beginning of year ​ 196,021 ​ 180,663 ​ 116,133 Cash and cash equivalents at end of year ​ $ 154,374 ​ $ 196,021 ​ $ 180,663 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Supplemental disclosures of cash flow information: ​ ​ ​ ​ Cash paid for interest ​ $ 560 ​ $ 2,555 ​ $ 4,306 Supplemental disclosures of noncash financing activities: ​ ​ ​ Dividends declared and unpaid ​ $ 23,235 ​ $ 22,695 ​ $ 21,342 Advances from subsidiaries ​ 482 ​ 932 ​ 1,691 Common stock issued for acquisition ​ 0 ​ 76,942 ​ 0

FAIR VALUE (Tables)

FAIR VALUE (Tables)	12 Months Ended
	Dec. 31, 2021
FAIR VALUE
Fair Value Measured on a Recurring Basis	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2021 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total Fair (000’s omitted) Level 1 Level 2 Level 3 Value Available-for-sale investment securities: ​ ​ ​ ​ U.S. Treasury and agency securities ​ $ 3,900,924 ​ $ 97,640 ​ $ 0 ​ $ 3,998,564 Obligations of state and political subdivisions ​ 0 ​ 430,289 ​ 0 ​ 430,289 Government agency mortgage-backed securities ​ 0 ​ 477,056 ​ 0 ​ 477,056 Corporate debt securities ​ 0 ​ 7,962 ​ 0 ​ 7,962 Government agency collateralized mortgage obligations ​ 0 ​ 20,339 ​ 0 ​ 20,339 Total available-for-sale investment securities ​ 3,900,924 ​ 1,033,286 ​ 0 ​ 4,934,210 Equity securities ​ 463 ​ 0 ​ 0 ​ 463 Commitments to originate real estate loans for sale ​ ​ 0 ​ ​ 0 ​ ​ 51 ​ ​ 51 Forward sales commitments ​ ​ 0 ​ ​ 32 ​ ​ 0 ​ ​ 32 Interest rate swap agreements asset ​ 0 ​ 296 ​ 0 ​ 296 Interest rate swap agreements liability ​ 0 ​ (3) ​ 0 ​ (3) Total ​ $ 3,901,387 ​ $ 1,033,611 ​ $ 51 ​ $ 4,935,049 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2020 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total Fair (000’s omitted) Level 1 Level 2 Level 3 Value Available-for-sale investment securities: ​ ​ ​ ​ U.S. Treasury and agency securities ​ $ 2,359,912 ​ $ 141,470 ​ $ 0 ​ $ 2,501,382 Obligations of state and political subdivisions ​ 0 ​ 475,660 ​ 0 ​ 475,660 Government agency mortgage-backed securities ​ 0 ​ 522,638 ​ 0 ​ 522,638 Corporate debt securities ​ 0 ​ 4,635 ​ 0 ​ 4,635 Government agency collateralized mortgage obligations ​ 0 ​ 43,577 ​ 0 ​ 43,577 Total available-for-sale investment securities ​ 2,359,912 ​ 1,187,980 ​ 0 ​ 3,547,892 Equity securities ​ 445 ​ 0 ​ 0 ​ 445 Mortgage loans held for sale ​ 0 ​ 1,622 ​ 0 ​ 1,622 Commitments to originate real estate loans for sale ​ ​ 0 ​ ​ 0 ​ ​ 14 ​ ​ 14 Forward sales commitments ​ ​ 0 ​ ​ 2 ​ ​ 0 ​ ​ 2 Interest rate swap agreements asset ​ 0 ​ 1,572 ​ 0 ​ 1,572 Interest rate swap agreements liability ​ 0 ​ (1,074) ​ ​ 0 ​ (1,074) Total ​ $ 2,360,357 ​ $ 1,190,102 ​ $ 14 ​ $ 3,550,473 ​
Assets and Liabilities Measured on a Non-Recurring Basis	Assets and liabilities measured on a non-recurring basis: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2021 ​ December 31, 2020 ​ ​ ​ ​ ​ ​ ​ ​ Total Fair ​ ​ ​ ​ ​ ​ Total Fair (000's omitted) ​ Level 1 ​ Level 2 ​ Level 3 ​ Value ​ Level 1 ​ Level 2 ​ Level 3 ​ Value Individually assessed loans ​ $ 0 ​ $ 0 ​ $ 1,820 $ 1,820 ​ $ 0 ​ $ 0 ​ $ 25,063 $ 25,063 Other real estate owned ​ 0 ​ 0 ​ 718 718 ​ 0 ​ 0 ​ 883 883 Mortgage servicing rights ​ 0 ​ 0 ​ 810 810 ​ 0 ​ 0 ​ 682 682 Contingent consideration ​ ​ 0 ​ ​ 0 ​ ​ (3,100) ​ ​ (3,100) ​ ​ 0 ​ ​ 0 ​ ​ 0 ​ ​ 0 Total ​ $ 0 ​ $ 0 ​ $ 248 $ 248 ​ $ 0 ​ $ 0 ​ $ 26,628 $ 26,628 ​
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 as of December 31, 2021 are as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Significant Significant Unobservable ​ ​ ​ ​ ​ Valuation ​ Unobservable ​ Input Range (000’s omitted) ​ Fair Value ​ Technique ​ Inputs ​ (Weighted Average) Individually assessed loans ​ $ 1,820 Fair value of collateral Estimated cost of disposal/market adjustment ​ 9.0% - 43.1% (43.1%) ​ Other real estate owned ​ 718 Fair value of collateral Estimated cost of disposal/market adjustment ​ 31.8% - 42.3% (33.3%) ​ Commitments to originate real estate loans for sale ​ ​ 51 ​ Discounted cash flow ​ Embedded servicing value ​ ​ 1.0 % Mortgage servicing rights ​ 810 Discounted cash flow Weighted average constant prepayment rate ​ 6.4% - 15.2% (14.0%) ​ ​ ​ ​ ​ ​ ​ Weighted average discount rate ​ 2.3% - 2.7% (2.6%) ​ ​ ​ ​ ​ ​ ​ Adequate compensation ​ $ 7/loan ​ Contingent consideration ​ ​ (3,100) ​ Discounted cash flow ​ Discount rate ​ ​ 1.4% - 1.7% (1.5%) ​ ​ ​ ​ ​ ​ ​ ​ Probability adjusted level of retained revenue ​ ​ $3.0 million - $5.8 million ​ ​ The significant unobservable inputs used in the determination of fair value of assets classified as Level 3 on a recurring or non-recurring basis as of December 31, 2020 are as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Significant Significant Unobservable ​ ​ ​ ​ ​ Valuation ​ Unobservable ​ Input Range (000’s omitted) ​ Fair Value ​ Technique ​ Inputs ​ (Weighted Average) Individually assessed loans ​ $ 25,063 Fair value of collateral Estimated cost of disposal/market adjustment ​ 9.0% - 78.4% (52.7%) ​ Other real estate owned ​ 883 Fair value of collateral Estimated cost of disposal/market adjustment ​ 11.3% - 52.9% (34.0%) ​ Commitments to originate real estate loans for sale ​ ​ 14 ​ Discounted cash flow ​ Embedded servicing value ​ ​ 1.0 % Mortgage servicing rights ​ 682 Discounted cash flow Weighted average constant prepayment rate ​ 9.8% - 18.8% (17.6%) ​ ​ ​ ​ ​ ​ ​ Weighted average discount rate ​ 1.7% - 2.2% (2.1%) ​ ​ ​ ​ ​ ​ ​ Adequate compensation ​ $ 7/loan ​ ​
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 December 31, 2021 and 2020 are as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2021 ​ December 31, 2020 ​ Carrying ​ Carrying ​ (000's omitted) ​ Value ​ Fair Value ​ Value ​ Fair Value Financial assets: ​ ​ ​ ​ Net loans ​ $ 7,323,770 ​ $ 7,523,024 ​ $ 7,355,083 ​ $ 7,655,044 Financial liabilities: ​ ​ ​ ​ ​ ​ ​ ​ Deposits ​ 12,911,168 ​ 12,911,197 ​ 11,224,974 ​ 11,239,628 Securities sold under agreement to repurchase, short-term ​ 324,720 ​ 324,720 ​ 284,008 ​ 284,008 Other Federal Home Loan Bank borrowings ​ 1,888 ​ 1,907 ​ 6,658 ​ 6,758 Subordinated notes payable ​ 3,277 ​ 3,277 ​ 3,303 ​ 3,303 Subordinated debt held by unconsolidated subsidiary trusts ​ 0 ​ 0 ​ 77,320 ​ 77,320 ​

DERIVATIVE INSTRUMENTS (Tables)

DERIVATIVE INSTRUMENTS (Tables)	12 Months Ended
	Dec. 31, 2021
DERIVATIVE INSTRUMENTS
Amounts Related to Cumulative Basis Adjustments for Fair Value Hedges	As of December 31, 2021 and 2020, the following amounts were recorded in the consolidated statement of condition related to cumulative basis adjustments for fair value hedges: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (000’s omitted) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Cumulative Amount of Fair Value Hedging Line Item in the Consolidated ​ Carrying Amount of the Hedged ​ Adjustment Included in the Carrying Statement of Condition in Which ​ Assets ​ Amount of the Hedged Assets the Hedged Item Is Included December 31, 2021 December 31, 2020 December 31, 2021 December 31, 2020 Loans ​ $ 5,400 ​ $ 5,675 ​ $ (293) ​ $ (498) ​
Fair Value of Derivative Instruments	Fair values of derivative instruments as of December 31, 2021 are as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (000’s omitted) ​ December 31, 2021 ​ ​ ​ Derivative Assets ​ Derivative Liabilities ​ ​ ​ Consolidated Statement of ​ Fair ​ Consolidated Statement of Condition ​ Fair ​ ​ ​ Condition Location Value Location Value ​ Derivatives designated as hedging instruments under Subtopic 815-20 ​ ​ ​ ​ ​ ​ Interest rate swaps Other assets ​ $ 293 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Derivatives not designated as hedging instruments under Subtopic 815-20 ​ ​ ​ ​ ​ Interest rate swaps Other assets ​ 3 Accrued interest and other liabilities $ 3 ​ Commitments to originate real estate loans for sale ​ Other assets ​ ​ 51 ​ ​ ​ ​ ​ ​ Forward sales commitments ​ Other assets ​ ​ 32 ​ ​ ​ ​ ​ ​ Total derivatives ​ $ 379 $ 3 ​ ​ Fair values of derivative instruments as of December 31, 2020 are as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (000’s omitted) December 31, 2020 ​ ​ Derivative Assets ​ Derivative Liabilities ​ Consolidated Statement of ​ ​ Consolidated Statement of Condition ​ ​ ​ Condition Location Fair Value Location Fair Value Derivatives designated as hedging instruments under Subtopic 815-20 ​ ​ ​ Interest rate swaps ​ Other assets ​ $ 498 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Derivatives not designated as hedging instruments under Subtopic 815-20 ​ ​ ​ Interest rate swaps ​ Other assets ​ 1,074 Accrued interest and other liabilities ​ $ 1,074 Commitments to originate real estate loans for sale ​ ​ Other assets ​ ​ 14 ​ ​ ​ ​ ​ Forward sales commitments ​ ​ Other assets ​ ​ 2 ​ ​ ​ ​ ​ Total derivatives ​ ​ ​ ​ $ 1,588 ​ $ 1,074 ​

VARIABLE INTEREST ENTITIES (Tab

VARIABLE INTEREST ENTITIES (Tables)	12 Months Ended
	Dec. 31, 2021
VARIABLE INTEREST ENTITIES
Carrying Amount and Classification of Assets and Liabilities of 706 North Clinton	The carrying amount of the assets and liabilities of 706 North Clinton and the classification of these assets and liabilities in the Company’s consolidated statements of condition at December 31 is as follows: ​ ​ ​ ​ ​ ​ ​ ​ (000’s omitted) 2021 2020 Cash and cash equivalents ​ $ 198 ​ $ 157 Premises and equipment, net ​ 5,618 ​ 5,782 Other assets ​ 57 ​ 48 Total assets ​ $ 5,873 ​ $ 5,987 Accrued interest and other liabilities / Total liabilities ​ $ 0 ​ $ 0 ​

SEGMENT INFORMATION (Tables)

SEGMENT INFORMATION (Tables)	12 Months Ended
	Dec. 31, 2021
SEGMENT INFORMATION
Schedule of Segment Reporting Information by Segment	​ Information about reportable segments and reconciliation of the information to the consolidated financial statements follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Employee ​ ​ ​ ​ ​ ​ ​ Consolidated (000’s omitted) Banking Benefit Services All Other Eliminations Total 2021 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net interest income ​ $ 374,078 ​ $ 293 ​ $ 41 ​ $ 0 ​ $ 374,412 Provision for credit losses ​ ​ (8,839) ​ ​ 0 ​ ​ 0 ​ ​ 0 ​ ​ (8,839) Noninterest revenue ​ ​ 67,910 ​ ​ 116,621 ​ ​ 68,834 ​ ​ (7,130) ​ ​ 246,235 Amortization of intangible assets ​ ​ 4,744 ​ ​ 6,033 ​ ​ 3,274 ​ ​ 0 ​ ​ 14,051 Acquisition expenses ​ ​ 638 ​ ​ 36 ​ ​ 27 ​ ​ 0 ​ ​ 701 Acquisition-related contingent consideration adjustment ​ ​ 0 ​ ​ 200 ​ ​ 0 ​ ​ 0 ​ ​ 200 Other operating expenses ​ ​ 265,525 ​ ​ 64,423 ​ ​ 50,368 ​ ​ (7,130) ​ ​ 373,186 Income before income taxes ​ $ 179,920 ​ $ 46,222 ​ $ 15,206 ​ $ 0 ​ $ 241,348 Assets ​ $ 15,325,732 ​ $ 257,879 ​ $ 97,391 ​ $ (128,345) ​ $ 15,552,657 Goodwill ​ $ 689,868 ​ $ 85,321 ​ $ 23,920 ​ $ 0 ​ $ 799,109 Core deposit intangibles & Other intangibles ​ $ 9,087 ​ $ 40,018 ​ $ 16,121 ​ $ 0 ​ $ 65,226 2020 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net interest income ​ $ 367,237 ​ $ 943 ​ $ 223 ​ $ 0 ​ $ 368,403 Provision for credit losses ​ 14,212 ​ 0 ​ 0 ​ 0 ​ 14,212 Noninterest revenue ​ 69,578 ​ 103,456 ​ 61,599 ​ (6,214) ​ 228,419 Amortization of intangible assets ​ 5,515 ​ 5,724 ​ 3,058 ​ 0 ​ 14,297 Acquisition expenses ​ 4,933 ​ 0 ​ 0 ​ 0 ​ 4,933 Other operating expenses ​ 255,955 ​ 60,709 ​ 46,854 ​ (6,214) ​ 357,304 Income before income taxes ​ $ 156,200 ​ $ 37,966 ​ $ 11,910 ​ $ 0 ​ $ 206,076 Assets ​ $ 13,762,325 ​ $ 217,780 ​ $ 82,849 ​ $ (131,860) ​ $ 13,931,094 Goodwill ​ $ 690,121 ​ $ 83,275 ​ $ 20,312 ​ $ 0 ​ $ 793,708 Core deposit intangibles & Other intangibles ​ $ 13,831 ​ $ 32,051 ​ $ 7,058 ​ $ 0 ​ $ 52,940 2019 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net interest income ​ $ 358,334 ​ $ 665 ​ $ 176 ​ $ 0 ​ $ 359,175 Provision for credit losses ​ 8,430 ​ 0 ​ 0 ​ 0 ​ 8,430 Noninterest revenue ​ 75,067 ​ 99,483 ​ 59,075 ​ (3,006) ​ 230,619 Amortization of intangible assets ​ 5,751 ​ 6,770 ​ 3,435 ​ 0 ​ 15,956 Acquisition expenses ​ 8,608 ​ 0 ​ 0 ​ 0 ​ 8,608 Other operating expenses ​ 245,870 ​ 59,428 ​ 45,170 ​ (3,006) ​ 347,462 Income before income taxes ​ $ 164,742 ​ $ 33,950 ​ $ 10,646 ​ $ 0 ​ $ 209,338 Assets ​ $ 11,225,509 ​ $ 209,690 ​ $ 76,351 ​ $ (101,255) ​ $ 11,410,295 Goodwill ​ $ 670,223 ​ $ 83,275 ​ $ 20,312 ​ $ 0 ​ $ 773,810 Core deposit intangibles & Other intangibles ​ $ 16,418 ​ $ 37,775 ​ $ 8,920 ​ $ 0 ​ $ 63,113

SUMMARY OF SIGNIFICANT ACCOUN_3

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details) $ in Millions	12 Months Ended
	Dec. 31, 2021USD ($)itemsegmentcomponentcountrysubsidiaryOffice	Dec. 31, 2020USD ($)	Dec. 31, 2019USD ($)
Nature of Operations [Abstract]
Number of significant consolidated subsidiaries owned | subsidiary	2
Number of bank branches | Office	206
Number Of Operating Location | item	12
Risks and Uncertainties [Abstract]
Number of main components of economic risk | component	3
Wealth Management Services [Abstract]
Number of types of performance obligations | item	2
Contract Balances [Abstract]
Accounts receivable	$ 31.6	$ 30.3
Unbilled fee revenue	9.1	7.7
Unearned revenue	2.2	1.4
Cash and Cash Equivalents [Abstract]
Cash due from banks	11	7.7
Allowance for Loan Losses [Abstract]
Accrued interest and fees receivable	16.7	22.2
Other Real Estate [Abstract]
Other real estate	0.7	0.9
Investments in Real Estate Limited Partnerships [Abstract]
Unfunded commitments	0.2
Impairment losses related to real estate partnerships	0
Advertising [Abstract]
Advertising costs	5.2	6.1	$ 7.1
Available-for-sale Securities [Member]
Allowance for Loan Losses [Abstract]
Accrued interest and fees receivable	$ 15.8	$ 13.3
Land Improvements [Member]
Property, Plant and Equipment, Gross [Abstract]
Estimated useful life	20 years
Minimum | LIHTC [Member]
Investments in Real Estate Limited Partnerships [Abstract]
Ownership interest	5.00%
Minimum | Equipment [Member]
Property, Plant and Equipment, Gross [Abstract]
Estimated useful life	2 years
Minimum | Software [Member]
Property, Plant and Equipment, Gross [Abstract]
Estimated useful life	3 years
Minimum | Hardware [Member]
Property, Plant and Equipment, Gross [Abstract]
Estimated useful life	3 years
Minimum | Building and Building Improvements [Member]
Property, Plant and Equipment, Gross [Abstract]
Estimated useful life	10 years
Minimum | Core deposit intangibles
Intangible Assets [Abstract]
Intangible asset useful life (amortization period)	7 years
Minimum | Customer Relationships [Member]
Intangible Assets [Abstract]
Intangible asset useful life (amortization period)	7 years
Maximum
Impaired and Other Nonaccrual Loans [Abstract]
Threshold balance of loans individually evaluated for impairment	$ 0.5
Maximum | LIHTC [Member]
Investments in Real Estate Limited Partnerships [Abstract]
Ownership interest	99.99%
Maximum | Equipment [Member]
Property, Plant and Equipment, Gross [Abstract]
Estimated useful life	20 years
Maximum | Software [Member]
Property, Plant and Equipment, Gross [Abstract]
Estimated useful life	7 years
Maximum | Hardware [Member]
Property, Plant and Equipment, Gross [Abstract]
Estimated useful life	7 years
Maximum | Building and Building Improvements [Member]
Property, Plant and Equipment, Gross [Abstract]
Estimated useful life	40 years
Maximum | Core deposit intangibles
Intangible Assets [Abstract]
Intangible asset useful life (amortization period)	20 years
Maximum | Customer Relationships [Member]
Intangible Assets [Abstract]
Intangible asset useful life (amortization period)	20 years
BPAS [Member]
Nature of Operations [Abstract]
Number of significant consolidated subsidiaries owned | segment	5
Hand Benefits & Trust [Member]
Nature of Operations [Abstract]
Number of significant consolidated subsidiaries owned | segment	1
NRS [Member]
Nature of Operations [Abstract]
Number of significant consolidated subsidiaries owned | segment	1
Upstate New York.
Nature of Operations [Abstract]
Number of counties where the bank has facilities | country	42
PENNSYLVANIA
Nature of Operations [Abstract]
Number of counties where the bank has facilities | country	6
Vermont [Member]
Nature of Operations [Abstract]
Number of counties where the bank has facilities | country	12
Massachusetts [Member]
Nature of Operations [Abstract]
Number of counties where the bank has facilities | country	1

ACQUISITIONS (Details)

ACQUISITIONS (Details) shares in Thousands, $ in Thousands	Oct. 04, 2021USD ($)	Aug. 02, 2021USD ($)	Jul. 01, 2021USD ($)	Jun. 01, 2021USD ($)	Jun. 12, 2020USD ($)countryOfficeshares	Sep. 18, 2019USD ($)	Jul. 12, 2019USD ($)countryOffice	Jan. 02, 2019USD ($)	Dec. 31, 2021USD ($)itemcountry	Dec. 31, 2020USD ($)	Dec. 31, 2019USD ($)
Acquisitions [Abstract]
Purchase price of acquisition											$ 95,034
Deposits									$ 0		568,161
Loans									0		479,877
Contingent consideration									2,900		0
Goodwill									799,109	$ 793,708	773,810
Cash						$ 500			29,329	(34,360)	4,653
Investment securities									0		39,770
Acquisition-related contingent consideration adjustment									$ 200	0	0
Upstate New York.
Acquisitions [Abstract]
Number of counties where the bank has facilities | country									42
Customer Lists [Member]
Acquisitions [Abstract]
Intangibles						$ 500
NuVantage Insurance, Inc. [Member]
Acquisitions [Abstract]
Intangibles				$ 1,400
Goodwill				1,400					$ 5,654
Revenue earned				700
Direct expenses				600
Cash				$ 2,900
NuVantage Insurance, Inc. [Member] | Minimum | Probability Adjusted Level Of Retained Revenue
Acquisitions [Abstract]
Contingent consideration, measurement input 2									5,600
Fringe Benefits Design of Minnesota, Inc ("FBD") [Member]
Acquisitions [Abstract]
Purchase price of acquisition									16,750
Deposits									0
Loans									0
Contingent consideration			$ 1,400						1,400
Goodwill			2,000						2,046
Revenue earned			2,800
Direct expenses			2,500
Cash			$ 15,400
Increase (decrease) in other liabilities as a result of reclassification and adjustment									20
Increase (decrease) in goodwill as a result of fair value adjustment									20
Investment securities									$ 0
Contingent consideration, measurement input			1.05						1.50
Period considered for additional consideration based on future retained revenue			2 years
Consideration payable term			3 years
Acquisition-related contingent consideration adjustment									$ 200
Fair value contingent consideration adjustment									1,600
Fringe Benefits Design of Minnesota, Inc ("FBD") [Member] | Maximum
Acquisitions [Abstract]
Contingent consideration			$ 2,700						2,700
Fringe Benefits Design of Minnesota, Inc ("FBD") [Member] | Maximum | Probability Adjusted Level Of Retained Revenue
Acquisitions [Abstract]
Contingent consideration, measurement input 2			5,800						5,800
Fringe Benefits Design of Minnesota, Inc ("FBD") [Member] | Minimum
Acquisitions [Abstract]
Contingent consideration			0						0
Fringe Benefits Design of Minnesota, Inc ("FBD") [Member] | Minimum | Probability Adjusted Level Of Retained Revenue
Acquisitions [Abstract]
Contingent consideration, measurement input 2			5,600
Fringe Benefits Design of Minnesota, Inc ("FBD") [Member] | Customer Lists [Member]
Acquisitions [Abstract]
Intangibles			$ 14,000
Steuben Trust Corporation [Member]
Acquisitions [Abstract]
Purchase price of acquisition										98,555
Assets acquired					$ 607,800
Deposits					(516,300)					516,274
Loans					339,700					339,017
Contingent consideration										0
Goodwill					20,000					19,981	39,970
Revenue earned									13,100	7,700
Direct expenses									5,100	2,600
Cash					$ 98,600
Issuance of common shares (in shares) | shares					1,360
Issuance of common shares					$ 21,600
Increase (decrease) in other liabilities as a result of reclassification and adjustment									(300)
Increase (decrease) in goodwill as a result of fair value adjustment									(300)
Investment securities					$ 180,500					180,497
Steuben Trust Corporation [Member] | Western New York State [Member]
Acquisitions [Abstract]
Number of new counties where the bank has extended footprints | country					2
Number of counties where the bank has facilities | country					4
Number of branch locations | Office					11
Thomas Gregory Associates [Member]
Acquisitions [Abstract]
Purchase price of acquisition									13,120
Deposits									0
Loans									0
Contingent consideration		$ 1,500							1,500
Intangibles		10,900
Goodwill		2,200							2,170
Revenue earned		600
Direct expenses		600
Cash		$ 11,600
Investment securities									0
Period considered for additional consideration based on future retained revenue		3 years
Thomas Gregory Associates [Member] | Within Two Years From Acquisition [Member]
Acquisitions [Abstract]
Consideration payable term		2 years
Thomas Gregory Associates [Member] | Within Three Years From Acquisition [Member]
Acquisitions [Abstract]
Consideration payable term		3 years
Thomas Gregory Associates [Member] | Maximum
Acquisitions [Abstract]
Contingent consideration		$ 3,400							$ 3,400
Contingent consideration, measurement input		1.09							1.65
Thomas Gregory Associates [Member] | Maximum | Probability Adjusted Level Of Retained Revenue
Acquisitions [Abstract]
Contingent consideration, measurement input 2		$ 3,800							$ 3,400
Thomas Gregory Associates [Member] | Minimum
Acquisitions [Abstract]
Contingent consideration		$ 0							$ 0
Contingent consideration, measurement input		0.82							1.38
Thomas Gregory Associates [Member] | Minimum | Probability Adjusted Level Of Retained Revenue
Acquisitions [Abstract]
Contingent consideration, measurement input 2		$ 2,300							$ 3,000
Elmira Savings Bank [Member]
Acquisitions [Abstract]
Number of Branch Locations of Acquiree Bank	12
Number Of Country | item									5
Purchase price of acquisition	$ 82,800
Kinderhook Bank Corp [Member]
Acquisitions [Abstract]
Deposits							$ 568,200
Loans							479,900
Goodwill							40,000
Revenue earned									$ 11,800	16,300	10,600
Direct expenses									7,100	$ 7,400	$ 4,700
Cash							$ 93,400
Number of branch locations | Office							11
Investment securities							$ 39,800
Kinderhook Bank Corp [Member] | Upstate New York [Member]
Acquisitions [Abstract]
Assets acquired							$ 642,800
Number of counties where the bank has facilities | country							5
Wealth Resources Network, Inc [Member]
Acquisitions [Abstract]
Cash								$ 1,200
Wealth Resources Network, Inc [Member] | Customer Lists [Member]
Acquisitions [Abstract]
Intangibles								$ 1,200
Segment Total [Member]
Acquisitions [Abstract]
Purchase price of acquisition									$ 32,770

ACQUISITIONS, Estimated Fair Va

ACQUISITIONS, Estimated Fair Value of Assets Acquired and Liabilities Assumed (Details) - USD ($) $ in Thousands	Aug. 02, 2021	Jul. 01, 2021	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Jun. 12, 2020	Jul. 12, 2019
Consideration :
Cash			$ 29,870		$ 95,034
Community Bank System, Inc. common stock			0		0
Contingent consideration			2,900		0
Total net consideration					95,034
Recognized amounts of identifiable assets acquired and liabilities assumed:
Cash and cash equivalents			541		90,381
Investment securities			0		39,770
Loans			0		479,877
Premises and equipment, net			760		13,970
Accrued interest and fees receivable			0		1,130
Other assets			579		14,109
Deposits			0		(568,161)
Other liabilities			(1,101)		(2,922)
Other Federal Home Loan Bank borrowings			0		(2,420)
Subordinated notes payable			0		(13,831)
Subordinated debt held by unconsolidated subsidiary trusts			0		(2,062)
Total identifiable assets, net			27,116		55,064
Goodwill			799,109	$ 793,708	773,810
Core deposit intangibles
Recognized amounts of identifiable assets acquired and liabilities assumed:
Intangibles			0		3,573
Other intangibles
Recognized amounts of identifiable assets acquired and liabilities assumed:
Intangibles			26,337		1,650
Thomas Gregory Associates [Member]
Consideration :
Cash			11,620
Community Bank System, Inc. common stock			0
Contingent consideration	$ 1,500		1,500
Total net consideration			13,120
Recognized amounts of identifiable assets acquired and liabilities assumed:
Cash and cash equivalents			0
Investment securities			0
Loans			0
Premises and equipment, net			279
Accrued interest and fees receivable			0
Other assets			0
Intangibles	10,900
Deposits			0
Other liabilities			(229)
Other Federal Home Loan Bank borrowings			0
Subordinated notes payable			0
Subordinated debt held by unconsolidated subsidiary trusts			0
Total identifiable assets, net			10,950
Goodwill	$ 2,200		2,170
Thomas Gregory Associates [Member] | Core deposit intangibles
Recognized amounts of identifiable assets acquired and liabilities assumed:
Intangibles			0
Thomas Gregory Associates [Member] | Other intangibles
Recognized amounts of identifiable assets acquired and liabilities assumed:
Intangibles			10,900
Fringe Benefits Design of Minnesota, Inc ("FBD") [Member]
Consideration :
Cash			15,350
Community Bank System, Inc. common stock			0
Contingent consideration		$ 1,400	1,400
Total net consideration			16,750
Recognized amounts of identifiable assets acquired and liabilities assumed:
Cash and cash equivalents			541
Investment securities			0
Loans			0
Premises and equipment, net			282
Accrued interest and fees receivable			0
Other assets			579
Deposits			0
Other liabilities			(698)
Other Federal Home Loan Bank borrowings			0
Subordinated notes payable			0
Subordinated debt held by unconsolidated subsidiary trusts			0
Total identifiable assets, net			14,704
Goodwill		$ 2,000	2,046
Fringe Benefits Design of Minnesota, Inc ("FBD") [Member] | Core deposit intangibles
Recognized amounts of identifiable assets acquired and liabilities assumed:
Intangibles			0
Fringe Benefits Design of Minnesota, Inc ("FBD") [Member] | Other intangibles
Recognized amounts of identifiable assets acquired and liabilities assumed:
Intangibles			14,000
NuVantage Insurance Corporation [Member]
Consideration :
Cash			2,900
Community Bank System, Inc. common stock			0
Contingent consideration			0
Total net consideration			2,900
Recognized amounts of identifiable assets acquired and liabilities assumed:
Cash and cash equivalents			0
Investment securities			0
Loans			0
Premises and equipment, net			199
Accrued interest and fees receivable			0
Other assets			0
Deposits			0
Other liabilities			(174)
Other Federal Home Loan Bank borrowings			0
Subordinated notes payable			0
Subordinated debt held by unconsolidated subsidiary trusts			0
Total identifiable assets, net			1,462
Goodwill			1,438
NuVantage Insurance Corporation [Member] | Core deposit intangibles
Recognized amounts of identifiable assets acquired and liabilities assumed:
Intangibles			0
NuVantage Insurance Corporation [Member] | Other intangibles
Recognized amounts of identifiable assets acquired and liabilities assumed:
Intangibles			$ 1,437
Kinderhook Bank Corp [Member]
Recognized amounts of identifiable assets acquired and liabilities assumed:
Investment securities							$ 39,800
Loans							479,900
Deposits							(568,200)
Goodwill							$ 40,000
Steuben Trust Corporation [Member]
Consideration :
Cash				21,613
Community Bank System, Inc. common stock				76,942
Contingent consideration				0
Total net consideration				98,555
Recognized amounts of identifiable assets acquired and liabilities assumed:
Cash and cash equivalents				55,973
Investment securities				180,497		$ 180,500
Loans				339,017		339,700
Premises and equipment, net				7,764
Accrued interest and fees receivable				2,701
Other assets				17,675
Deposits				(516,274)		516,300
Other liabilities				(4,841)
Other Federal Home Loan Bank borrowings				(6,000)
Subordinated notes payable				0
Subordinated debt held by unconsolidated subsidiary trusts				(2,062)
Total identifiable assets, net				78,574
Goodwill				19,981	$ 39,970	$ 20,000
Steuben Trust Corporation [Member] | Core deposit intangibles
Recognized amounts of identifiable assets acquired and liabilities assumed:
Intangibles				2,928
Steuben Trust Corporation [Member] | Other intangibles
Recognized amounts of identifiable assets acquired and liabilities assumed:
Intangibles				$ 1,196

ACQUISITIONS - Summary of Loans

ACQUISITIONS - Summary of Loans Acquired (Details) - USD ($) $ in Thousands	Jun. 12, 2020	Jul. 12, 2019
Kinderhook Bank Corp [Member]
Summary of loans acquired [Abstract]
Contractually required principal and interest at acquisition		$ 649,734
Contractual cash flows not expected to be collected		(9,648)
Expected cash flows at acquisition		640,086
Interest component of expected cash flows		(160,209)
Fair value of acquired loans		479,877
Kinderhook Bank Corp [Member] | Acquired Impaired Loans [Member]
Summary of loans acquired [Abstract]
Contractually required principal and interest at acquisition		13,350
Contractual cash flows not expected to be collected		(4,176)
Expected cash flows at acquisition		9,174
Interest component of expected cash flows		(551)
Fair value of acquired loans		8,623
Kinderhook Bank Corp [Member] | Acquired Non Impaired Loans [Member]
Summary of loans acquired [Abstract]
Contractually required principal and interest at acquisition		636,384
Contractual cash flows not expected to be collected		(5,472)
Expected cash flows at acquisition		630,912
Interest component of expected cash flows		(159,658)
Fair value of acquired loans		$ 471,254
Steuben Trust Corporation [Member] | PCD Loans [Member]
Summary of loans acquired [Abstract]
Par value of loans at acquisition	$ 35,906
Allowance for credit losses at acquisition	(668)
Non-credit premium at acquisition	103
Fair value of acquired loans	35,341
Steuben Trust Corporation [Member] | Non-PCD Loans [Member]
Summary of loans acquired [Abstract]
Contractually required principal and interest at acquisition	400,738
Contractual cash flows not expected to be collected	(2,994)
Expected cash flows at acquisition	397,744
Interest component of expected cash flows	(94,068)
Fair value of acquired loans	$ 303,676

ACQUISITIONS - Intangible Asset

ACQUISITIONS - Intangible Asset, Goodwill and Acquisition-related Expenses (Details) - USD ($) $ in Thousands	Jul. 12, 2019	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Fair Value of Subordinated Notes Payable [Abstract]
Subordinated notes payable		$ 3,277	$ 3,303
Summary of loans acquired [Abstract]
Merger and acquisition integration related (recoveries) expenses		$ 701	4,933	$ 8,608
Kinderhook Bank Corp [Member] | Core deposit intangibles
Finite-Lived Intangible Assets, Net [Abstract]
Intangible asset useful life (amortization period)		8 years
Kinderhook Bank Corp [Member] | Other intangibles
Finite-Lived Intangible Assets, Net [Abstract]
Intangible asset useful life (amortization period)		8 years
Kinderhook Bank Corp [Member] | Subordinated Notes Maturing in February 2028 [Member]
Fair Value of Subordinated Notes Payable [Abstract]
Subordinated notes payable	$ 3,000
Fixed interest rate percentage	6.00%
Maturity date	Feb. 29, 2028
Kinderhook Bank Corp [Member] | Subordinated Notes Maturing in November 2025 [Member]
Fair Value of Subordinated Notes Payable [Abstract]
Subordinated notes payable	$ 10,000
Fixed interest rate percentage	6.375%
Maturity date	Nov. 30, 2025
Steuben Trust Corporation [Member]
Summary of loans acquired [Abstract]
Merger and acquisition integration related (recoveries) expenses		$ 700	$ 4,900	$ 8,600
Fringe Benefits Design of Minnesota, Inc ("FBD") [Member]
Finite-Lived Intangible Assets, Net [Abstract]
Intangible asset useful life (amortization period)		15 years
Thomas Gregory Associates [Member]
Finite-Lived Intangible Assets, Net [Abstract]
Intangible asset useful life (amortization period)		13 years

ACQUISITIONS - Supplemental Pro

ACQUISITIONS - Supplemental Pro Forma Financial Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Business Acquisition [Line Items]
Total revenue, net of interest expense, pro forma	$ 607,382	$ 626,229
Net income, pro forma	171,147	$ 180,237
Steuben Trust Corporation [Member]
Business Acquisition [Line Items]
Acquisitions-related expenses	$ 4,800

INVESTMENT SECURITIES - Availab

INVESTMENT SECURITIES - Available-for-Sale Portfolio (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Available-for-Sale Portfolio [Abstract]
Amortized cost	$ 4,980,102	$ 3,427,779
Gross unrealized gains	65,387	136,901
Gross unrealized losses	111,279	16,788
Fair value	4,934,210	3,547,892
Debt Securities, Available-for-sale, Fair Value to Amortized Cost [Abstract]
Amortized cost	4,980,102
Debt Securities, Available-for-sale	4,934,210
U.S. Treasury and Agency Securities
Debt Securities, Available-for-sale, Fair Value to Amortized Cost [Abstract]
Amortized cost	4,064,624	2,423,236
Gross unrealized gains	39,997	94,741
Gross unrealized losses	106,057	16,595
Debt Securities, Available-for-sale	3,998,564	2,501,382
Obligations of State and Political Subdivisions
Debt Securities, Available-for-sale, Fair Value to Amortized Cost [Abstract]
Amortized cost	413,019	451,028
Gross unrealized gains	17,326	24,632
Gross unrealized losses	56	0
Debt Securities, Available-for-sale	430,289	475,660
Government Agency Mortgage-Backed Securities
Debt Securities, Available-for-sale, Fair Value to Amortized Cost [Abstract]
Amortized cost	474,506	506,540
Gross unrealized gains	7,615	16,280
Gross unrealized losses	5,065	182
Debt Securities, Available-for-sale	477,056	522,638
Corporate debt securities
Debt Securities, Available-for-sale, Fair Value to Amortized Cost [Abstract]
Amortized cost	8,000	4,499
Gross unrealized gains	39	137
Gross unrealized losses	77	1
Debt Securities, Available-for-sale	7,962	4,635
Government Agency Collateralized Mortgage Obligations
Debt Securities, Available-for-sale, Fair Value to Amortized Cost [Abstract]
Amortized cost	19,953	42,476
Gross unrealized gains	410	1,111
Gross unrealized losses	24	10
Debt Securities, Available-for-sale	20,339	43,577
Federal Reserve Bank Stock [Member]
Debt Securities, Available-for-sale, Fair Value to Amortized Cost [Abstract]
Gross unrealized losses	0	0
Other Equity Securities [Member]
Debt Securities, Available-for-sale, Fair Value to Amortized Cost [Abstract]
Gross unrealized losses	0	0
Federal Home Loan Bank Common Stock [Member]
Debt Securities, Available-for-sale, Fair Value to Amortized Cost [Abstract]
Gross unrealized losses	$ 0	$ 0

INVESTMENT SECURITIES - Equity

INVESTMENT SECURITIES - Equity and Other Securities (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Equity and Other Securities [Abstract]
Amortized cost	$ 43,917	$ 46,511
Gross unrealized gains	962	944
Gross unrealized losses	0	0
Fair value	44,879	47,455
Equity Securities, at Fair Value [Abstract]
Amortized cost	251	251
Gross unrealized gains	212	194
Gross unrealized losses	0	0
Fair value	463	445
Federal Home Loan Bank Common Stock [Member]
Other Equity Securities, at Adjusted Cost [Abstract]
Amortized cost	7,188	7,468
Gross unrealized gains	0	0
Gross unrealized losses	0	0
Fair value	7,188	7,468
Federal Reserve Bank Stock [Member]
Other Equity Securities, at Adjusted Cost [Abstract]
Amortized cost	33,916	33,916
Gross unrealized gains	0	0
Gross unrealized losses	0	0
Fair value	33,916	33,916
Other Equity Securities [Member]
Other Equity Securities, at Adjusted Cost [Abstract]
Amortized cost	2,562	4,876
Gross unrealized gains	750	750
Gross unrealized losses	0	0
Fair value	$ 3,312	$ 5,626

INVESTMENT SECURITIES - Investm

INVESTMENT SECURITIES - Investment Securities in a Continuous Unrealized Loss Position (Details) $ in Thousands	Dec. 31, 2021USD ($)position	Dec. 31, 2020USD ($)position
Available-for-Sale Securities in Unrealized Loss Positions, Number of Positions [Abstract]
Less than 12 months | position	240	117
12 months or longer | position	66	3
Total | position	306	120
Available-for-Sale Securities, in Unrealized Loss Position, Fair Value [Abstract]
Less than 12 months	$ 1,395,578	$ 913,612
12 months or longer	967,788	14
Total	2,363,366	913,626
Available-for-Sale Securities, in Unrealized Loss Position, Gross Unrealized Losses [Abstract]
Less than 12 months	17,505	16,788
12 months or longer	93,774	0
Total	111,279	16,788
Available-for-sale, allowance for credit losses	$ 0	$ 0
U.S. Treasury and Agency Securities
Available-for-Sale Securities in Unrealized Loss Positions, Number of Positions [Abstract]
Less than 12 months	47	13
12 months or longer | position	13	0
Total | position	60	13
Available-for-Sale Securities, in Unrealized Loss Position, Fair Value [Abstract]
Less than 12 months		$ 831,015
12 months or longer	$ 900,462	0
Total	2,124,563	831,015
Available-for-Sale Securities, in Unrealized Loss Position, Gross Unrealized Losses [Abstract]
Less than 12 months	14,873	16,595
12 months or longer	91,184	0
Total	$ 106,057	$ 16,595
Obligations of State and Political Subdivisions
Available-for-Sale Securities in Unrealized Loss Positions, Number of Positions [Abstract]
Less than 12 months	27	1
12 months or longer | position	0	0
Total | position	27	1
Available-for-Sale Securities, in Unrealized Loss Position, Fair Value [Abstract]
Less than 12 months		$ 358
12 months or longer	$ 0	0
Total	23,966	358
Available-for-Sale Securities, in Unrealized Loss Position, Gross Unrealized Losses [Abstract]
Less than 12 months	56	0
12 months or longer	0	0
Total	$ 56	$ 0
Government Agency Mortgage-Backed Securities
Available-for-Sale Securities in Unrealized Loss Positions, Number of Positions [Abstract]
Less than 12 months	147	89
12 months or longer | position	52	2
Total | position	199	91
Available-for-Sale Securities, in Unrealized Loss Position, Fair Value [Abstract]
Less than 12 months		$ 75,992
12 months or longer	$ 67,273	14
Total	206,715	76,006
Available-for-Sale Securities, in Unrealized Loss Position, Gross Unrealized Losses [Abstract]
Less than 12 months	2,475	182
12 months or longer	2,590	0
Total	$ 5,065	$ 182
Corporate debt securities
Available-for-Sale Securities in Unrealized Loss Positions, Number of Positions [Abstract]
Less than 12 months	1	1
12 months or longer | position	0	0
Total | position	1	1
Available-for-Sale Securities, in Unrealized Loss Position, Fair Value [Abstract]
Less than 12 months		$ 1,001
12 months or longer	$ 0	0
Total	4,923	1,001
Available-for-Sale Securities, in Unrealized Loss Position, Gross Unrealized Losses [Abstract]
Less than 12 months	77	1
12 months or longer	0	0
Total	$ 77	$ 1
Government Agency Collateralized Mortgage Obligations
Available-for-Sale Securities in Unrealized Loss Positions, Number of Positions [Abstract]
Less than 12 months	18	13
12 months or longer | position	1	1
Total | position	19	14
Available-for-Sale Securities, in Unrealized Loss Position, Fair Value [Abstract]
Less than 12 months		$ 5,246
12 months or longer	$ 53	0
Total	3,199	5,246
Available-for-Sale Securities, in Unrealized Loss Position, Gross Unrealized Losses [Abstract]
Less than 12 months	24	10
12 months or longer	0	0
Total	$ 24	$ 10

INVESTMENT SECURITIES - Amortiz

INVESTMENT SECURITIES - Amortized Cost and Estimated Fair Value of Debt Securities by Contractual Maturity (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Available-for-Sale, Debt Maturities, Amortized Cost [Abstract]
Due in one year or less	$ 156,262
Due after one through five years	876,849
Due after five years through ten years	1,958,202
Due after ten years	1,494,330
Subtotal	4,485,643
Amortized cost	4,980,102
Available-for-Sale, Debt Maturities, Fair Value [Abstract]
Due in one year or less	158,119
Due after one through five years	891,772
Due after five years through ten years	1,962,453
Due after ten years	1,424,471
Subtotal	4,436,815
Fair value	4,934,210
Government Agency Mortgage-Backed Securities
Available-for-Sale, Debt Maturities, Amortized Cost [Abstract]
Amortized cost	474,506	$ 506,540
Available-for-Sale, Debt Maturities, Fair Value [Abstract]
Fair value	477,056	522,638
Government Agency Collateralized Mortgage Obligations
Available-for-Sale, Debt Maturities, Amortized Cost [Abstract]
Amortized cost	19,953	42,476
Available-for-Sale, Debt Maturities, Fair Value [Abstract]
Fair value	20,339	43,577
U.S. Treasury and Agency Securities
Available-for-Sale, Debt Maturities, Amortized Cost [Abstract]
Amortized cost	4,064,624	2,423,236
Available-for-Sale, Debt Maturities, Fair Value [Abstract]
Fair value	$ 3,998,564	$ 2,501,382

INVESTMENT SECURITIES - Inves_2

INVESTMENT SECURITIES - Investment Securities Pledged as Collateral (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Investment Securities Pledged as Collateral
Investment securities pledged to collateralize certain deposits and borrowings	$ 2,320	$ 2,030
U.S. Treasury and Agency Securities | Securities Sold under Agreements to Repurchase [Member]
Investment Securities Pledged as Collateral
Investment securities pledged to collateralize certain deposits and borrowings	$ 485.4	$ 473.4

INVESTMENT SECURITIES - Proceed

INVESTMENT SECURITIES - Proceeds from Sales of Securities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Debt Securities, Available-for-sale [Line Items]
Proceeds from sales of securities	$ 0	$ 0	$ 590,179
U.S. Treasury and Agency Securities
Debt Securities, Available-for-sale [Line Items]
Proceeds from sales of securities			590,200
Gross realized gains			5,000
Gross realized losses			$ 100

LOANS - Loan Summary (Details)

LOANS - Loan Summary (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Loans receivable, net
Gross loans, including deferred origination costs	$ 7,373,639	$ 7,415,952
Allowance for credit losses	(49,869)	(60,869)	$ (49,911)
Net loans	7,323,770	7,355,083
Net deferred loan origination costs	34,900	25,500
Loans receivable, related parties [Roll Forward]
Balance at beginning of year	15,549	17,486
New loans	2,500	4,194
Payments	(4,276)	(6,131)
Balance at end of year	13,773	15,549
Commercial Portfolio Segment | Business Lending
Loans receivable, net
Gross loans, including deferred origination costs	3,075,904	3,440,077
Allowance for credit losses			(19,426)
Commercial Portfolio Segment | Consumer Mortgage
Loans receivable, net
Allowance for credit losses			(10,269)
Residential Portfolio Segment | Consumer Mortgage
Loans receivable, net
Gross loans, including deferred origination costs	2,556,114	2,401,499
Consumer Portfolio Segment | Business Lending
Loans receivable, net
Allowance for credit losses	(21,021)	(28,190)
Consumer Portfolio Segment | Consumer Mortgage
Loans receivable, net
Allowance for credit losses	(10,017)	(10,672)
Consumer Portfolio Segment | Consumer Indirect
Loans receivable, net
Gross loans, including deferred origination costs	1,189,749	1,021,885
Allowance for credit losses	(11,737)	(13,696)	(13,712)
Consumer Portfolio Segment | Consumer Direct
Loans receivable, net
Gross loans, including deferred origination costs	153,811	152,657
Allowance for credit losses	(2,306)	(3,207)	(3,255)
Consumer Portfolio Segment | Home Equity
Loans receivable, net
Gross loans, including deferred origination costs	398,061	399,834
Allowance for credit losses	$ (1,814)	$ (2,222)	$ (2,129)

LOANS - Credit Quality By Past

LOANS - Credit Quality By Past Due Status (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Aged analysis of the company's loans
Nonaccrual	$ 1,500
Total loans	7,373,639	$ 7,415,952
Interest income on nonaccrual loans	0	0
Interest income on loans	2,300
Legacy Loan [Member]
Aged analysis of the company's loans
90 + days past due and still accruing	3,808	3,922
Nonaccrual	41,665	72,929
Total loans	7,373,639	7,415,952
Legacy Loan [Member] | Past Due 30 - 89 Days [Member]
Aged analysis of the company's loans
Total loans	28,022	34,759
Legacy Loan [Member] | Financial Asset, Past Due [Member]
Aged analysis of the company's loans
Total loans	73,495	111,610
Legacy Loan [Member] | Financial Asset, Not Past Due [Member]
Aged analysis of the company's loans
Total loans	7,300,144	7,304,342
Commercial Portfolio Segment | Business Lending
Aged analysis of the company's loans
Total loans	3,075,904	3,440,077
Commercial Portfolio Segment | Business Lending | Legacy Loan [Member]
Aged analysis of the company's loans
90 + days past due and still accruing	99	59
Nonaccrual	24,105	55,709
Total loans	3,075,904	3,440,077
Commercial Portfolio Segment | Business Lending | Legacy Loan [Member] | Past Due 30 - 89 Days [Member]
Aged analysis of the company's loans
Total loans	5,540	4,896
Commercial Portfolio Segment | Business Lending | Legacy Loan [Member] | Financial Asset, Past Due [Member]
Aged analysis of the company's loans
Total loans	29,744	60,664
Commercial Portfolio Segment | Business Lending | Legacy Loan [Member] | Financial Asset, Not Past Due [Member]
Aged analysis of the company's loans
Total loans	3,046,160	3,379,413
Residential Portfolio Segment | Consumer Mortgage
Aged analysis of the company's loans
Total loans	2,556,114	2,401,499
Residential Portfolio Segment | Consumer Mortgage | Legacy Loan [Member]
Aged analysis of the company's loans
90 + days past due and still accruing	3,328	3,051
Nonaccrual	15,027	14,970
Total loans	2,556,114	2,401,499
Residential Portfolio Segment | Consumer Mortgage | Legacy Loan [Member] | Past Due 30 - 89 Days [Member]
Aged analysis of the company's loans
Total loans	10,297	13,236
Residential Portfolio Segment | Consumer Mortgage | Legacy Loan [Member] | Financial Asset, Past Due [Member]
Aged analysis of the company's loans
Total loans	28,652	31,257
Residential Portfolio Segment | Consumer Mortgage | Legacy Loan [Member] | Financial Asset, Not Past Due [Member]
Aged analysis of the company's loans
Total loans	2,527,462	2,370,242
Consumer Portfolio Segment | Consumer Indirect
Aged analysis of the company's loans
Total loans	1,189,749	1,021,885
Consumer Portfolio Segment | Consumer Indirect | Legacy Loan [Member]
Aged analysis of the company's loans
90 + days past due and still accruing	87	219
Nonaccrual	0	1
Total loans	1,189,749	1,021,885
Consumer Portfolio Segment | Consumer Indirect | Legacy Loan [Member] | Past Due 30 - 89 Days [Member]
Aged analysis of the company's loans
Total loans	9,611	13,161
Consumer Portfolio Segment | Consumer Indirect | Legacy Loan [Member] | Financial Asset, Past Due [Member]
Aged analysis of the company's loans
Total loans	9,698	13,381
Consumer Portfolio Segment | Consumer Indirect | Legacy Loan [Member] | Financial Asset, Not Past Due [Member]
Aged analysis of the company's loans
Total loans	1,180,051	1,008,504
Consumer Portfolio Segment | Consumer Direct
Aged analysis of the company's loans
Total loans	153,811	152,657
Consumer Portfolio Segment | Consumer Direct | Legacy Loan [Member]
Aged analysis of the company's loans
90 + days past due and still accruing	22	28
Nonaccrual	1	3
Total loans	153,811	152,657
Consumer Portfolio Segment | Consumer Direct | Legacy Loan [Member] | Past Due 30 - 89 Days [Member]
Aged analysis of the company's loans
Total loans	796	1,170
Consumer Portfolio Segment | Consumer Direct | Legacy Loan [Member] | Financial Asset, Past Due [Member]
Aged analysis of the company's loans
Total loans	819	1,201
Consumer Portfolio Segment | Consumer Direct | Legacy Loan [Member] | Financial Asset, Not Past Due [Member]
Aged analysis of the company's loans
Total loans	152,992	151,456
Consumer Portfolio Segment | Home Equity
Aged analysis of the company's loans
Total loans	398,061	399,834
Consumer Portfolio Segment | Home Equity | Legacy Loan [Member]
Aged analysis of the company's loans
90 + days past due and still accruing	272	565
Nonaccrual	2,532	2,246
Total loans	398,061	399,834
Consumer Portfolio Segment | Home Equity | Legacy Loan [Member] | Past Due 30 - 89 Days [Member]
Aged analysis of the company's loans
Total loans	1,778	2,296
Consumer Portfolio Segment | Home Equity | Legacy Loan [Member] | Financial Asset, Past Due [Member]
Aged analysis of the company's loans
Total loans	4,582	5,107
Consumer Portfolio Segment | Home Equity | Legacy Loan [Member] | Financial Asset, Not Past Due [Member]
Aged analysis of the company's loans
Total loans	$ 393,479	$ 394,727

LOANS - Amount of Business Lend

LOANS - Amount of Business Lending Loans by Credit Quality Categories (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Term Loans Amortized Cost Basis by Origination Year
Loans	$ 7,373,639	$ 7,415,952
Legacy Loan [Member]
Term Loans Amortized Cost Basis by Origination Year
Loans	7,373,639	7,415,952
Business Lending
Term Loans Amortized Cost Basis by Origination Year
2021	532,141
2020	341,665	881,201
2019	351,064	391,969
2018	334,790	373,807
2017	230,502	263,820
2016		275,730
Prior	705,731	660,921
Revolving Loans Amortized Cost Basis	580,011	592,629
Total past due	3,075,904	3,440,077
Business Lending | Pass [Member]
Term Loans Amortized Cost Basis by Origination Year
2021	524,302
2020	328,885	860,178
2019	320,638	351,350
2018	248,175	312,087
2017	186,074	217,138
2016		231,453
Prior	584,912	543,999
Revolving Loans Amortized Cost Basis	524,553	483,018
Total past due	2,717,539	2,999,223
Business Lending | Special Mention [Member]
Term Loans Amortized Cost Basis by Origination Year
2021	5,969
2020	11,013	14,687
2019	10,111	36,041
2018	46,318	28,410
2017	22,524	21,875
2016		29,386
Prior	57,134	51,657
Revolving Loans Amortized Cost Basis	27,444	52,732
Total past due	180,513	234,788
Business Lending | Classified [Member]
Term Loans Amortized Cost Basis by Origination Year
2021	1,870
2020	1,767	6,336
2019	20,315	4,560
2018	40,235	30,422
2017	21,904	24,807
2016		14,891
Prior	63,685	65,157
Revolving Loans Amortized Cost Basis	27,511	56,000
Total past due	177,287	202,173
Business Lending | Doubtful [Member]
Term Loans Amortized Cost Basis by Origination Year
2021	0
2020	0	0
2019	0	18
2018	62	2,888
2017	0	0
2016		0
Prior	0	108
Revolving Loans Amortized Cost Basis	503	879
Total past due	565	3,893
Consumer Mortgage
Term Loans Amortized Cost Basis by Origination Year
2021	683,550
2020	352,373	375,637
2019	269,694	330,825
2018	173,187	248,468
2017	172,187	240,217
2016		246,256
Prior	880,095	942,393
Revolving Loans Amortized Cost Basis	25,028	17,703
Total past due	2,556,114	2,401,499
Consumer Mortgage | FICO AB [Member]
Term Loans Amortized Cost Basis by Origination Year
2021	514,680
2020	229,305	260,588
2019	183,469	227,027
2018	113,749	166,913
2017	116,852	164,051
2016		161,256
Prior	569,365	617,685
Revolving Loans Amortized Cost Basis	0	321
Total past due	1,727,420	1,597,841
Consumer Mortgage | FICO AB [Member] | Performing [Member]
Term Loans Amortized Cost Basis by Origination Year
2021	514,680
2020	229,039	260,588
2019	183,469	227,027
2018	113,618	166,638
2017	116,417	163,653
2016		160,911
Prior	566,129	614,976
Revolving Loans Amortized Cost Basis	0	321
Total past due	1,723,352	1,594,114
Consumer Mortgage | FICO AB [Member] | Nonperforming Financial Instruments [Member]
Term Loans Amortized Cost Basis by Origination Year
2021	0
2020	266	0
2019	0	0
2018	131	275
2017	435	398
2016		345
Prior	3,236	2,709
Revolving Loans Amortized Cost Basis	0	0
Total past due	4,068	3,727
Consumer Mortgage | FICO CDE [Member]
Term Loans Amortized Cost Basis by Origination Year
2021	168,870
2020	123,068	115,049
2019	86,225	103,798
2018	59,438	81,555
2017	55,335	76,166
2016		85,000
Prior	310,730	324,708
Revolving Loans Amortized Cost Basis	25,028	17,382
Total past due	828,694	803,658
Consumer Mortgage | FICO CDE [Member] | Performing [Member]
Term Loans Amortized Cost Basis by Origination Year
2021	168,870
2020	122,546	115,049
2019	85,253	102,788
2018	57,973	80,973
2017	54,396	75,289
2016		83,214
Prior	300,341	314,668
Revolving Loans Amortized Cost Basis	25,028	17,382
Total past due	814,407	789,363
Consumer Mortgage | FICO CDE [Member] | Nonperforming Financial Instruments [Member]
Term Loans Amortized Cost Basis by Origination Year
2021	0
2020	522	0
2019	972	1,010
2018	1,465	582
2017	939	877
2016		1,786
Prior	10,389	10,040
Revolving Loans Amortized Cost Basis	0	0
Total past due	14,287	14,295
Consumer Indirect
Term Loans Amortized Cost Basis by Origination Year
2021	590,857
2020	204,563	303,522
2019	182,458	305,953
2018	107,707	202,455
2017	39,402	86,514
2016		61,465
Prior	64,762	61,976
Revolving Loans Amortized Cost Basis	0	0
Total past due	1,189,749	1,021,885
Consumer Indirect | Performing [Member]
Term Loans Amortized Cost Basis by Origination Year
2021	590,857
2020	204,529	303,471
2019	182,458	305,901
2018	107,683	202,373
2017	39,385	86,497
2016		61,449
Prior	64,750	61,975
Revolving Loans Amortized Cost Basis	0	0
Total past due	1,189,662	1,021,666
Consumer Indirect | Nonperforming Financial Instruments [Member]
Term Loans Amortized Cost Basis by Origination Year
2021	0
2020	34	51
2019	0	52
2018	24	82
2017	17	17
2016		16
Prior	12	1
Revolving Loans Amortized Cost Basis	0	0
Total past due	87	219
Consumer Direct
Term Loans Amortized Cost Basis by Origination Year
2021	72,584
2020	28,909	49,182
2019	24,788	47,011
2018	12,341	27,874
2017	4,396	12,331
2016		5,232
Prior	4,575	4,149
Revolving Loans Amortized Cost Basis	6,218	6,878
Total past due	153,811	152,657
Consumer Direct | Performing [Member]
Term Loans Amortized Cost Basis by Origination Year
2021	72,584
2020	28,905	49,181
2019	24,770	46,992
2018	12,340	27,872
2017	4,396	12,326
2016		5,232
Prior	4,575	4,146
Revolving Loans Amortized Cost Basis	6,218	6,878
Total past due	153,788	152,627
Consumer Direct | Nonperforming Financial Instruments [Member]
Term Loans Amortized Cost Basis by Origination Year
2021	0
2020	4	1
2019	18	19
2018	1	2
2017	0	5
2016		0
Prior	0	3
Revolving Loans Amortized Cost Basis	0	0
Total past due	23	30
Home Equity
Term Loans Amortized Cost Basis by Origination Year
2021	76,041
2020	43,170	48,145
2019	36,037	48,804
2018	18,926	28,147
2017	15,265	23,628
2016		18,011
Prior	36,419	36,390
Revolving Loans Amortized Cost Basis	172,203	196,709
Total past due	398,061	399,834
Home Equity | Performing [Member]
Term Loans Amortized Cost Basis by Origination Year
2021	76,041
2020	43,106	48,145
2019	35,990	48,780
2018	18,824	28,074
2017	15,134	23,524
2016		17,828
Prior	35,740	35,900
Revolving Loans Amortized Cost Basis	170,422	194,773
Total past due	395,257	397,024
Home Equity | Nonperforming Financial Instruments [Member]
Term Loans Amortized Cost Basis by Origination Year
2021	0
2020	64	0
2019	47	24
2018	102	73
2017	131	104
2016		183
Prior	679	490
Revolving Loans Amortized Cost Basis	1,781	1,936
Total past due	$ 2,804	$ 2,810

LOANS - Summary of Impaired Loa

LOANS - Summary of Impaired Loans, Excluding Purchased Impaired (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Impaired loans
Loans with allowance allocation	$ 7,102	$ 27,437
Loans without allowance allocation	7,417	8,138
Carrying balance	14,519	35,575
Contractual balance	16,963	38,362
Specifically allocated allowance	566	3,874
Average carrying balance of individually assessed loans	33,400	12,200
Interest income on individually assessed loans	$ 0	$ 0

LOANS - Troubled Debt Restructu

LOANS - Troubled Debt Restructurings (TDRs) (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2021USD ($)loanborrower	Dec. 31, 2020USD ($)loan
Financing Receivable, Modifications [Line Items]
Deferral period under customer payment deferral program	180 days
TDRs, number	232	247
TDRs, amount	$ 8,239	$ 6,984
Loans modified in TDR during the year, number	54	55
Loans modified in TDR during the year, amount	$ 3,087	$ 1,756
Number of Borrowers Representing $4.2 Million in Outstanding Loan Balances | borrower	5
Outstanding Loan Balances of 5 Number of Consumer Borrowers	$ 4,200
Percentage of total loan outstanding	0.10%
Number of Borrowers Representing $4.1 Million in Outstanding Loan Balances | borrower	4
Outstanding Loan Balances of 4 Number of Borrowers	$ 4,100
Number of Borrowers Representing $0.1 Million in Outstanding Loan Balances | borrower	1
Outstanding Loan Balances of 1 Number of Borrowers	$ 100
Maximum
Financing Receivable, Modifications [Line Items]
Threshold balance of TDR loans collectively included in general loan loss allocation and qualitative review	500
Threshold balance of loan individually evaluated for impairment	$ 500
Nonaccrual [Member]
Financing Receivable, Modifications [Line Items]
TDRs, number	81	73
TDRs, amount	$ 3,940	$ 3,227
Accruing [Member]
Financing Receivable, Modifications [Line Items]
TDRs, number	151	174
TDRs, amount	$ 4,299	$ 3,757
Commercial Portfolio Segment | Business Lending
Financing Receivable, Modifications [Line Items]
TDRs, number | loan	14	10
TDRs, amount	$ 1,822	$ 720
Loans modified in TDR during the year, number | loan	5	1
Loans modified in TDR during the year, amount	$ 1,371	$ 4
Commercial Portfolio Segment | Business Lending | Nonaccrual [Member]
Financing Receivable, Modifications [Line Items]
TDRs, number | loan	10	6
TDRs, amount	$ 1,011	$ 529
Commercial Portfolio Segment | Business Lending | Accruing [Member]
Financing Receivable, Modifications [Line Items]
TDRs, number | loan	4	4
TDRs, amount	$ 811	$ 191
Residential Portfolio Segment | Consumer Mortgage
Financing Receivable, Modifications [Line Items]
TDRs, number | loan	108	104
TDRs, amount	$ 5,114	$ 4,679
Loans modified in TDR during the year, number | loan	24	17
Loans modified in TDR during the year, amount	$ 1,425	$ 1,339
Residential Portfolio Segment | Consumer Mortgage | Nonaccrual [Member]
Financing Receivable, Modifications [Line Items]
TDRs, number | loan	61	56
TDRs, amount	$ 2,694	$ 2,413
Residential Portfolio Segment | Consumer Mortgage | Accruing [Member]
Financing Receivable, Modifications [Line Items]
TDRs, number | loan	47	48
TDRs, amount	$ 2,420	$ 2,266
Consumer Portfolio Segment | Consumer Indirect
Financing Receivable, Modifications [Line Items]
TDRs, number | loan	72	86
TDRs, amount	$ 829	$ 951
Loans modified in TDR during the year, number | loan	23	31
Loans modified in TDR during the year, amount	$ 284	$ 333
Consumer Portfolio Segment | Consumer Indirect | Nonaccrual [Member]
Financing Receivable, Modifications [Line Items]
TDRs, number | loan	0	0
TDRs, amount	$ 0	$ 0
Consumer Portfolio Segment | Consumer Indirect | Accruing [Member]
Financing Receivable, Modifications [Line Items]
TDRs, number | loan	72	86
TDRs, amount	$ 829	$ 951
Consumer Portfolio Segment | Consumer Direct
Financing Receivable, Modifications [Line Items]
TDRs, number | loan	16	23
TDRs, amount	$ 7	$ 85
Loans modified in TDR during the year, number | loan	2	3
Loans modified in TDR during the year, amount	$ 7	$ 10
Consumer Portfolio Segment | Consumer Direct | Nonaccrual [Member]
Financing Receivable, Modifications [Line Items]
TDRs, number | loan	0	0
TDRs, amount	$ 0	$ 0
Consumer Portfolio Segment | Consumer Direct | Accruing [Member]
Financing Receivable, Modifications [Line Items]
TDRs, number | loan	16	23
TDRs, amount	$ 7	$ 85
Consumer Portfolio Segment | Home Equity
Financing Receivable, Modifications [Line Items]
TDRs, number | loan	22	24
TDRs, amount	$ 467	$ 549
Loans modified in TDR during the year, number | loan	0	3
Loans modified in TDR during the year, amount	$ 0	$ 70
Consumer Portfolio Segment | Home Equity | Nonaccrual [Member]
Financing Receivable, Modifications [Line Items]
TDRs, number | loan	10	11
TDRs, amount	$ 235	$ 285
Consumer Portfolio Segment | Home Equity | Accruing [Member]
Financing Receivable, Modifications [Line Items]
TDRs, number | loan	12	13
TDRs, amount	$ 232	$ 264

LOANS - Allowance for Loan Loss

LOANS - Allowance for Loan Losses (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Allowance for credit losses - loans [Roll Forward]
Balance, beginning of period	$ 60,869	$ 49,911
Charge-offs	(8,965)
Recoveries	6,118
Provision	(8,839)	14,212	$ 8,430
Balance, end of period	49,869	60,869	49,911
PCD Loans [Member]
Allowance for credit losses - loans [Roll Forward]
Balance, beginning of period		0
Balance, end of period			0
Commercial Portfolio Segment | Business Lending
Allowance for credit losses - loans [Roll Forward]
Balance, beginning of period		19,426
Balance, end of period			19,426
Commercial Portfolio Segment | Consumer Mortgage
Allowance for credit losses - loans [Roll Forward]
Balance, beginning of period		10,269
Balance, end of period			10,269
Consumer Portfolio Segment | Business Lending
Allowance for credit losses - loans [Roll Forward]
Balance, beginning of period	28,190
Charge-offs	(1,618)
Recoveries	689
Balance, end of period	21,021	28,190
Consumer Portfolio Segment | Consumer Mortgage
Allowance for credit losses - loans [Roll Forward]
Balance, beginning of period	10,672
Charge-offs	(426)
Recoveries	91
Balance, end of period	10,017	10,672
Consumer Portfolio Segment | Consumer Indirect
Allowance for credit losses - loans [Roll Forward]
Balance, beginning of period	13,696	13,712
Charge-offs	(5,160)
Recoveries	4,346
Balance, end of period	11,737	13,696	13,712
Consumer Portfolio Segment | Consumer Direct
Allowance for credit losses - loans [Roll Forward]
Balance, beginning of period	3,207	3,255
Charge-offs	(1,232)
Recoveries	793
Balance, end of period	2,306	3,207	3,255
Consumer Portfolio Segment | Home Equity
Allowance for credit losses - loans [Roll Forward]
Balance, beginning of period	2,222	2,129
Charge-offs	(225)
Recoveries	92
Balance, end of period	1,814	2,222	2,129
Unallocated Financing Receivables [Member]
Allowance for credit losses - loans [Roll Forward]
Balance, beginning of period	1,000	957
Charge-offs	0
Recoveries	0
Balance, end of period	1,000	1,000	957
Topic ASC 326 [Member]
Allowance for credit losses - loans [Roll Forward]
Balance, beginning of period	60,869	51,268
Charge-offs		(10,664)
Recoveries		5,689
Balance, end of period		60,869	51,268
Topic ASC 326 [Member] | PCD Loans [Member]
Allowance for credit losses - loans [Roll Forward]
Balance, beginning of period	1,882	3,072
Charge-offs		(91)
Recoveries		440
Balance, end of period		1,882	3,072
Topic ASC 326 [Member] | Commercial Portfolio Segment | Business Lending
Allowance for credit losses - loans [Roll Forward]
Balance, beginning of period	28,190	19,714
Charge-offs		(1,497)
Recoveries		356
Provision		7,274
Balance, end of period		28,190	19,714
Topic ASC 326 [Member] | Commercial Portfolio Segment | Consumer Mortgage
Allowance for credit losses - loans [Roll Forward]
Balance, beginning of period	10,672	9,218
Charge-offs		(862)
Recoveries		130
Balance, end of period		10,672	9,218
Topic ASC 326 [Member] | Consumer Portfolio Segment | Consumer Indirect
Allowance for credit losses - loans [Roll Forward]
Balance, beginning of period	13,696	12,715
Charge-offs		(6,382)
Recoveries		3,992
Balance, end of period		13,696	12,715
Topic ASC 326 [Member] | Consumer Portfolio Segment | Consumer Direct
Allowance for credit losses - loans [Roll Forward]
Balance, beginning of period	3,207	2,612
Charge-offs		(1,633)
Recoveries		743
Balance, end of period		3,207	2,612
Topic ASC 326 [Member] | Consumer Portfolio Segment | Home Equity
Allowance for credit losses - loans [Roll Forward]
Balance, beginning of period	2,222	2,937
Charge-offs		(199)
Recoveries		28
Balance, end of period		2,222	2,937
Topic ASC 326 [Member] | Unallocated Financing Receivables [Member]
Allowance for credit losses - loans [Roll Forward]
Balance, beginning of period	$ 1,000	1,000
Charge-offs		0
Recoveries		0
Balance, end of period		$ 1,000	$ 1,000

LOANS - Allowance for Credit Lo

LOANS - Allowance for Credit Losses (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2021USD ($)	Dec. 31, 2020USD ($)
Allowance for credit losses - loans [Roll Forward]
Balance, beginning of period	$ 60,869	$ 49,911
Charge-offs	(8,965)
Recoveries	6,118
Provision	(8,153)
Balance, end of period	49,869	60,869
Liabilities for off-balance-sheet credit exposures [Roll Forward]
Beginning balance	1,489	0
Charge-offs	0
Recoveries	0
Provision	(686)
Ending balance	803	1,489
Total allowance for credit losses [Roll Forward]
Beginning balance	62,358	49,911
Charge-offs	(8,965)
Recoveries	6,118
Provision	(8,839)
Ending balance	$ 50,672	$ 62,358
Allowance for Credit Losses
Allowance for credit losses to total loans ratio	0.68
Basis points lower level		0.14
Accrued interest and fees receivable	$ 16,700	$ 22,200
Topic ASC 326 [Member]
Allowance for credit losses - loans [Roll Forward]
Balance, beginning of period	60,869	51,268
Charge-offs		(10,664)
Recoveries		5,689
Steuben acquisition		3,662
Provision		10,914
Balance, end of period		60,869
Liabilities for off-balance-sheet credit exposures [Roll Forward]
Beginning balance	1,489	1,185
Charge-offs		0
Recoveries		0
Steuben acquisition		67
Provision		237
Ending balance		1,489
Total allowance for credit losses [Roll Forward]
Beginning balance	62,358	52,453
Charge-offs		(10,664)
Recoveries		5,689
Steuben acquisition		3,729
Provision		11,151
Ending balance		62,358
Topic ASC 326 [Member] | Cumulative Effect Adjustment [Member]
Allowance for credit losses - loans [Roll Forward]
Balance, beginning of period		(1,357)
Liabilities for off-balance-sheet credit exposures [Roll Forward]
Beginning balance		1,185
Total allowance for credit losses [Roll Forward]
Beginning balance		2,542
Acquired Impaired Loans [Member]
Allowance for credit losses - loans [Roll Forward]
Balance, beginning of period	1,882	163
Charge-offs	(304)
Recoveries	107
Provision	289
Balance, end of period	1,974	1,882
Acquired Impaired Loans [Member] | Topic ASC 326 [Member]
Allowance for credit losses - loans [Roll Forward]
Balance, beginning of period	0	0
Charge-offs		0
Recoveries		0
Steuben acquisition		0
Provision		0
Balance, end of period		0
Acquired Impaired Loans [Member] | Topic ASC 326 [Member] | Cumulative Effect Adjustment [Member]
Allowance for credit losses - loans [Roll Forward]
Balance, beginning of period		163
PCD Loans [Member]
Allowance for credit losses - loans [Roll Forward]
Balance, beginning of period		0
PCD Loans [Member] | Topic ASC 326 [Member]
Allowance for credit losses - loans [Roll Forward]
Balance, beginning of period	1,882	3,072
Charge-offs		(91)
Recoveries		440
Steuben acquisition		668
Provision		(2,207)
Balance, end of period		1,882
PCD Loans [Member] | Topic ASC 326 [Member] | Cumulative Effect Adjustment [Member]
Allowance for credit losses - loans [Roll Forward]
Balance, beginning of period		(3,072)
Commercial Portfolio Segment | Business Lending
Allowance for credit losses - loans [Roll Forward]
Balance, beginning of period		19,426
Commercial Portfolio Segment | Business Lending | Topic ASC 326 [Member]
Allowance for credit losses - loans [Roll Forward]
Balance, beginning of period	28,190	19,714
Charge-offs		(1,497)
Recoveries		356
Steuben acquisition		2,343
Balance, end of period		28,190
Commercial Portfolio Segment | Business Lending | Topic ASC 326 [Member] | Cumulative Effect Adjustment [Member]
Allowance for credit losses - loans [Roll Forward]
Balance, beginning of period		288
Commercial Portfolio Segment | Consumer Mortgage
Allowance for credit losses - loans [Roll Forward]
Balance, beginning of period		10,269
Commercial Portfolio Segment | Consumer Mortgage | Topic ASC 326 [Member]
Allowance for credit losses - loans [Roll Forward]
Balance, beginning of period	10,672	9,218
Charge-offs		(862)
Recoveries		130
Steuben acquisition		146
Provision		2,040
Balance, end of period		10,672
Commercial Portfolio Segment | Consumer Mortgage | Topic ASC 326 [Member] | Cumulative Effect Adjustment [Member]
Allowance for credit losses - loans [Roll Forward]
Balance, beginning of period		1,051
Consumer Portfolio Segment | Business Lending
Allowance for credit losses - loans [Roll Forward]
Balance, beginning of period	28,190
Charge-offs	(1,618)
Recoveries	689
Provision	(6,240)
Balance, end of period	21,021	28,190
Consumer Portfolio Segment | Consumer Mortgage
Allowance for credit losses - loans [Roll Forward]
Balance, beginning of period	10,672
Charge-offs	(426)
Recoveries	91
Provision	(320)
Balance, end of period	10,017	10,672
Consumer Portfolio Segment | Consumer Indirect
Allowance for credit losses - loans [Roll Forward]
Balance, beginning of period	13,696	13,712
Charge-offs	(5,160)
Recoveries	4,346
Provision	(1,145)
Balance, end of period	11,737	13,696
Consumer Portfolio Segment | Consumer Indirect | Topic ASC 326 [Member]
Allowance for credit losses - loans [Roll Forward]
Balance, beginning of period	13,696	12,715
Charge-offs		(6,382)
Recoveries		3,992
Steuben acquisition		183
Provision		3,188
Balance, end of period		13,696
Consumer Portfolio Segment | Consumer Indirect | Topic ASC 326 [Member] | Cumulative Effect Adjustment [Member]
Allowance for credit losses - loans [Roll Forward]
Balance, beginning of period		997
Consumer Portfolio Segment | Consumer Direct
Allowance for credit losses - loans [Roll Forward]
Balance, beginning of period	3,207	3,255
Charge-offs	(1,232)
Recoveries	793
Provision	(462)
Balance, end of period	2,306	3,207
Consumer Portfolio Segment | Consumer Direct | Topic ASC 326 [Member]
Allowance for credit losses - loans [Roll Forward]
Balance, beginning of period	3,207	2,612
Charge-offs		(1,633)
Recoveries		743
Steuben acquisition		87
Provision		1,398
Balance, end of period		3,207
Consumer Portfolio Segment | Consumer Direct | Topic ASC 326 [Member] | Cumulative Effect Adjustment [Member]
Allowance for credit losses - loans [Roll Forward]
Balance, beginning of period		643
Consumer Portfolio Segment | Home Equity
Allowance for credit losses - loans [Roll Forward]
Balance, beginning of period	2,222	2,129
Charge-offs	(225)
Recoveries	92
Provision	(275)
Balance, end of period	1,814	2,222
Consumer Portfolio Segment | Home Equity | Topic ASC 326 [Member]
Allowance for credit losses - loans [Roll Forward]
Balance, beginning of period	2,222	2,937
Charge-offs		(199)
Recoveries		28
Steuben acquisition		235
Provision		(779)
Balance, end of period		2,222
Consumer Portfolio Segment | Home Equity | Topic ASC 326 [Member] | Cumulative Effect Adjustment [Member]
Allowance for credit losses - loans [Roll Forward]
Balance, beginning of period		(808)
Unallocated Financing Receivables [Member]
Allowance for credit losses - loans [Roll Forward]
Balance, beginning of period	1,000	957
Charge-offs	0
Recoveries	0
Provision	0
Balance, end of period	1,000	1,000
Unallocated Financing Receivables [Member] | Topic ASC 326 [Member]
Allowance for credit losses - loans [Roll Forward]
Balance, beginning of period	$ 1,000	1,000
Charge-offs		0
Recoveries		0
Steuben acquisition		0
Provision		0
Balance, end of period		1,000
Unallocated Financing Receivables [Member] | Topic ASC 326 [Member] | Cumulative Effect Adjustment [Member]
Allowance for credit losses - loans [Roll Forward]
Balance, beginning of period		$ (43)

LOANS - Carrying Amounts of Loa

LOANS - Carrying Amounts of Loans Purchased and Sold (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2021USD ($)
Carrying Amounts of Loans Purchased and Sold
Purchases	$ 0
Sales	23,881
Business Lending
Carrying Amounts of Loans Purchased and Sold
Purchases	0
Sales	3,748
Consumer Mortgage
Carrying Amounts of Loans Purchased and Sold
Purchases	0
Sales	20,133
Consumer Indirect
Carrying Amounts of Loans Purchased and Sold
Purchases	0
Sales	0
Consumer Direct
Carrying Amounts of Loans Purchased and Sold
Purchases	0
Sales	0
Home Equity
Carrying Amounts of Loans Purchased and Sold
Purchases	0
Sales	$ 0

PREMISES AND EQUIPMENT (Details

PREMISES AND EQUIPMENT (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Property, Plant and Equipment, Net [Abstract]
Premises and equipment, gross	$ 305,539	$ 312,434
Accumulated depreciation	(144,888)	(146,779)
Premises and equipment, net	160,651	165,655
Land and Land Improvements [Member]
Property, Plant and Equipment, Net [Abstract]
Premises and equipment, gross	31,884	29,070
Bank Premises [Member]
Property, Plant and Equipment, Net [Abstract]
Premises and equipment, gross	151,724	149,217
Equipment and Construction in Progress [Member]
Property, Plant and Equipment, Net [Abstract]
Premises and equipment, gross	85,391	93,013
Construction in Progress [Member]
Property, Plant and Equipment, Net [Abstract]
Premises and equipment, gross	4,786	6,226
Operating Lease Right-of-Use Assets [Member]
Property, Plant and Equipment, Net [Abstract]
Premises and equipment, gross	$ 31,754	$ 34,908

GOODWILL AND IDENTIFIABLE INT_3

GOODWILL AND IDENTIFIABLE INTANGIBLE ASSETS (Details) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Identifiable Intangible Assets
Gross carrying amount	$ 186,202,000	$ 159,865,000
Accumulated Amortization	(120,976,000)	(106,925,000)
Net Carrying Amount	65,226,000	52,940,000
Estimated aggregate amortization expense for each of five succeeding fiscal years
2022	13,668,000
2023	11,595,000
2024	9,782,000
2025	8,349,000
2026	7,494,000
Thereafter	14,338,000
Net Carrying Amount	65,226,000	52,940,000
Components of goodwill
Goodwill, net, beginning of period	793,708,000	773,810,000
Goodwill, net, activity	5,401,000	19,898,000
Goodwill, net, end of period	799,109,000	793,708,000
Servicing Asset at Fair Value, Amount [Roll Forward]
Carrying value before valuation allowance at beginning of period	1,430,000	972,000
Additions	233,000	715,000
Acquisitions	0	122,000
Amortization	(519,000)	(379,000)
Carrying value before valuation allowance at end of period	1,144,000	1,430,000
Valuation allowance balance at beginning of period	(219,000)	(298,000)
Impairment charges	(55,000)	(150,000)
Impairment recoveries	274,000	229,000
Valuation allowance balance at end of period	0	(219,000)
Net carrying value at end of period	1,144,000	1,211,000
Fair value of MSRs at end of period	1,469,000	1,384,000
Principal balance of mortgage loans sold during the year	20,133,000	79,709,000
Principal balance of loans serviced for others	296,506,000	351,759,000
Custodial escrow balances maintained in connection with loans serviced for others	$ 4,934,000	$ 5,583,000
Key economic assumptions used to estimate the value of the MSRs [Abstract]
Weighted-average contractual life	21 years 4 months 24 days	21 years 6 months
Weighted-average constant prepayment rate (CPR)	24.50%	30.40%
Weighted-average discount rate	2.60%	2.10%
Core deposit intangibles
Identifiable Intangible Assets
Gross carrying amount	$ 69,403,000	$ 69,403,000
Accumulated Amortization	(60,316,000)	(55,572,000)
Net Carrying Amount	9,087,000	13,831,000
Estimated aggregate amortization expense for each of five succeeding fiscal years
Net Carrying Amount	9,087,000	13,831,000
Other intangibles
Identifiable Intangible Assets
Gross carrying amount	116,799,000	90,462,000
Accumulated Amortization	(60,660,000)	(51,353,000)
Net Carrying Amount	56,139,000	39,109,000
Estimated aggregate amortization expense for each of five succeeding fiscal years
Net Carrying Amount	$ 56,139,000	$ 39,109,000

DEPOSITS (Details)

DEPOSITS (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
DEPOSITS.
Noninterest checking	$ 3,921,663	$ 3,361,768
Interest checking	3,201,225	2,876,420
Savings	2,255,961	1,949,517
Money market	2,603,988	2,103,498
Time	928,331	933,771
Total deposits	$ 12,911,168	$ 11,224,974

DEPOSITS - Interest on Deposits

DEPOSITS - Interest on Deposits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Interest on Deposits [Abstract]
Interest on interest checking	$ 1,142	$ 2,182	$ 3,678
Interest on savings	598	665	942
Interest on money market	1,393	2,685	5,836
Interest on time	8,498	11,229	10,004
Total interest on deposits	$ 11,631	$ 16,761	$ 20,460

DEPOSITS - Maturities of Time D

DEPOSITS - Maturities of Time Deposits (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Maturities of time deposits [Abstract]
2022	$ 579,595
2023	139,881
2024	162,317
2025	21,494
2026	25,010
Thereafter	34
Total	928,331	$ 933,771
Maturities of time deposits, accounts $250,000 or greater [Abstract]
2022	186,647
2023	7,408
2024	38,681
2025	2,102
2026	1,922
Thereafter	0
Total	$ 236,760

BORROWINGS, Outstanding Borrowi

BORROWINGS, Outstanding Borrowings (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
BORROWINGS
Subordinated notes payable, includes premium of $277 and $303, respectively	$ 3,277	$ 3,303
Subordinated debt held by unconsolidated subsidiary trusts	0	77,320
Securities sold under agreement to repurchase, short term	324,720	284,008
Other FHLB borrowings	1,888	6,658
Total borrowings	329,885	371,289
Subordinated notes payable, premium	$ 277	$ 303

BORROWINGS, Contractual Maturit

BORROWINGS, Contractual Maturity on Borrowings (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Debt Instruments [Abstract]
Carrying value	$ 329,885	$ 371,289
Weighted-average rate	0.32%
Weighted-average interest rate on borrowings during period	0.48%	1.27%
January 2, 2022 [Member]
Debt Instruments [Abstract]
Carrying value	$ 324,720
Weighted-average rate	0.27%
February 08, 2023 [Member]
Debt Instruments [Abstract]
Carrying value	$ 190
Weighted-average rate	1.79%
July 3, 2023 [Member]
Debt Instruments [Abstract]
Carrying value	$ 497
Weighted-average rate	2.25%
October 23, 2023 [Member]
Debt Instruments [Abstract]
Carrying value	$ 395
Weighted-average rate	1.50%
October 1, 2025 [Member]
Debt Instruments [Abstract]
Carrying value	$ 275
Weighted-average rate	1.50%
February 28, 2028 [Member]
Debt Instruments [Abstract]
Carrying value	$ 3,277
Weighted-average rate	4.67%
March 1, 2029 [Member]
Debt Instruments [Abstract]
Carrying value	$ 531
Weighted-average rate	2.50%

BORROWINGS, Preferred Securitie

BORROWINGS, Preferred Securities (Details) - USD ($) $ in Millions	Mar. 15, 2021	Sep. 15, 2020
Community Capital Trust IV [Member]
Mandatorily Redeemable Preferred Securities [Abstract]
Redemption of debentures and associated preferred securities	$ 77.3
Kinderhook Capital Trust [Member]
Mandatorily Redeemable Preferred Securities [Abstract]
Redemption of debentures and associated preferred securities		$ 2.1

INCOME TAXES, Provision for Inc

INCOME TAXES, Provision for Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Current [Abstract]
Federal	$ 35,507	$ 35,728	$ 34,804
State and other	8,158	8,008	7,773
Deferred [Abstract]
Federal	5,493	(2,005)	(699)
State and other	2,496	(331)	(1,603)
Provision for income taxes	51,654	41,400	40,275
Unrecognized Tax Benefits	$ 0	$ 0	$ 0

INCOME TAXES, Components of Net

INCOME TAXES, Components of Net Deferred Tax Liability (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Components of net deferred tax liability [Abstract]
Allowance for loan losses	$ 12,435	$ 15,004
Employee benefits	7,708	7,552
Operating lease liabilities	7,955	8,601
Other, net	1,250	900
Deferred tax asset	29,348	32,057
Investment securities	7,227	43,325
Goodwill and intangibles	41,917	40,802
Operating lease right-of-use assets	7,693	8,384
Loan origination costs	8,993	7,904
Depreciation	535	3,089
Mortgage servicing rights	278	291
Pension	22,950	16,987
Deferred tax liability	89,593	120,782
Net deferred tax liability	$ (60,245)	$ (88,725)

INCOME TAXES, Effective Tax Rat

INCOME TAXES, Effective Tax Rate Reconciliation (Details)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Effective tax rate reconciliation [Abstract]
Federal statutory income tax rate	21.00%	21.00%	21.00%
Increase (reduction) in taxes resulting from [Abstract]
Tax-exempt interest	(1.10%)	(1.50%)	(1.50%)
State income taxes, net of federal benefit	3.60%	3.00%	2.50%
Stock-based compensation	(0.90%)	(0.80%)	(1.60%)
Federal tax credits	(1.00%)	(1.30%)	(1.30%)
Other, net	(0.20%)	(0.30%)	0.10%
Effective income tax rate	21.40%	20.10%	19.20%

LIMITS ON DIVIDENDS AND OTHER_2

LIMITS ON DIVIDENDS AND OTHER REVENUE SOURCES (Details) $ in Millions	Dec. 31, 2021USD ($)
LIMITS ON DIVIDENDS AND OTHER REVENUE SOURCES
Undivided profits legally available for the payments of dividends	$ 94.2
Percentage of Bank's capital and surplus that can be transferred to Company, maximum	10.00%
Aggregate percentage of Bank's capital and surplus that can be transferred to Company, maximum	20.00%

BENEFIT PLANS - Funded Status a

BENEFIT PLANS - Funded Status and Amounts Recognized in Balance Sheets and AOCI (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2009
Change in plan assets:
Fair value of plan assets at beginning of year	$ 1,400
Fair value of plan assets at end of year		$ 1,400
Amounts recognized in the consolidated statement of condition were:
AOCI at year end	15,470	28,873	$ 34,882
Accumulated other comprehensive income (loss), negative postretirement medical plan amendment, arising during period, net of tax				$ 3,500
Additional unamortized actuarial gain	1,100
Pension Benefits [Member]
Change in benefit obligation:
Benefit obligation at the beginning of year	190,361	162,084
Service cost	5,920	5,750	5,081
Interest cost	5,036	5,657	6,264
Plan amendment / acquisition	0	13,598
Participant contributions	0	0
Deferred actuarial (gain)/loss	(4,881)	13,954
Benefits paid	(13,166)	(10,682)
Benefit obligation at end of year	183,270	190,361	162,084
Change in plan assets:
Fair value of plan assets at beginning of year	272,600	227,323
Actual return of plan assets	27,614	33,543
Participant contributions	0	0
Employer contributions	3,639	7,993
Plan acquisition	0	14,423
Benefits paid	(13,166)	(10,682)
Fair value of plan assets at end of year	290,687	272,600	227,323
Over/(Under) funded status at year end	107,417	82,239
Amounts recognized in the consolidated statement of condition were:
Other assets	127,538	101,849
Other liabilities	(20,121)	(19,610)
Amounts recognized in the consolidated statement of condition were:
Net loss	16,977	34,290
Net prior service cost (credit)	3,969	4,348
Pre-tax AOCI	20,946	38,638
Taxes	(5,236)	(9,488)
AOCI at year end	15,710	29,150
Pension Benefits [Member] | Unfunded Plan Member
Change in plan assets:
Fair value of plan assets at end of year	3,500
Pension Benefits [Member] | Nonqualified Plan [Member] | Unfunded Plan Member
Change in plan assets:
Employer contributions	2,900	3,900
Pension Benefits [Member] | Restoration Plan [Member] | Nonqualified Plan [Member] | Unfunded Plan Member
Amounts recognized in the consolidated statement of condition were:
Initial projected benefit obligation	30	30
Post-retirement Benefits [Member]
Change in benefit obligation:
Benefit obligation at the beginning of year	1,718	1,677
Service cost	0	0	0
Interest cost	44	57	70
Plan amendment / acquisition	0	0
Participant contributions	0	0
Deferred actuarial (gain)/loss	(85)	114
Benefits paid	(148)	(130)
Benefit obligation at end of year	1,529	1,718	1,677
Change in plan assets:
Fair value of plan assets at beginning of year	0	0
Actual return of plan assets	0	0
Participant contributions	0	0
Employer contributions	148	130
Plan acquisition	0	0
Benefits paid	(148)	(130)
Fair value of plan assets at end of year	0	0	$ 0
Over/(Under) funded status at year end	(1,529)	(1,718)
Amounts recognized in the consolidated statement of condition were:
Other assets	0	0
Other liabilities	(1,529)	(1,718)
Amounts recognized in the consolidated statement of condition were:
Net loss	585	715
Net prior service cost (credit)	(907)	(1,086)
Pre-tax AOCI	(322)	(371)
Taxes	82	94
AOCI at year end	$ (240)	(277)
Supplemental Pension Plans [Member] | Key Executives [Member]
Pension Plan [Abstract]
Defined Benefit Plan, Funding Status [Extensible List]	Unfunded Plan Member
Change in benefit obligation:
Benefit obligation at the beginning of year	$ 19,600
Benefit obligation at end of year	19,800	19,600
Amounts recognized in the consolidated statement of condition were:
Benefit obligation for defined benefit pension plan prior to plan revaluation	$ 163,100	$ 170,800

BENEFIT PLANS - Amounts Recogni

BENEFIT PLANS - Amounts Recognized in AOCI, Net of Tax (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Amounts recognized in AOCI, net of tax [Abstract]
Total	$ (13,403)	$ (6,009)	$ 2,045
Pension Benefits [Member]
Amounts recognized in AOCI, net of tax [Abstract]
Prior service cost/(credit)	(288)	222
Net (gain) loss	(13,152)	(6,423)
Total	(13,440)	(6,201)
Post-retirement Benefits [Member]
Amounts recognized in AOCI, net of tax [Abstract]
Prior service cost/(credit)	136	136
Net (gain) loss	(99)	56
Total	$ 37	$ 192

BENEFIT PLANS - Weighted-averag

BENEFIT PLANS - Weighted-average Assumptions Used to Determine Benefit Obligations (Details)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Pension Benefits [Member]
Weighed average assumption used in calculating benefit obligations [Abstract]
Discount rate	3.10%	2.80%
Expected return on plan assets	6.70%	7.00%
Pension Benefits [Member] | Year 2022 [Member]
Weighed average assumption used in calculating benefit obligations [Abstract]
Rate of compensation increase	4.00%
Pension Benefits [Member] | Year 2023 [Member]
Weighed average assumption used in calculating benefit obligations [Abstract]
Rate of compensation increase	3.50%
while employed
Weighed average assumption used in calculating benefit obligations [Abstract]
Interest crediting rates	6.00%	6.00%
after termination
Weighed average assumption used in calculating benefit obligations [Abstract]
Interest crediting rates	1.94%	1.42%
Post-retirement Benefits [Member]
Weighed average assumption used in calculating benefit obligations [Abstract]
Discount rate	3.10%	2.80%

BENEFIT PLANS - Net Periodic Be

BENEFIT PLANS - Net Periodic Benefit Cost (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Prior service costs [Abstract]
Maximum percentage of net gain or loss over the greater of the projected benefit obligation or the market-related value of assets without requiring amortization	10.00%
Pension Benefits [Member]
Net periodic benefit cost [Abstract]
Service cost	$ 5,920	$ 5,750	$ 5,081
Interest cost	5,036	5,657	6,264
Expected return on plan assets	(18,783)	(16,306)	(14,311)
Plan amendment	0	(637)	0
Amortization of unrecognized net loss	3,600	3,239	2,568
Amortization of prior service cost	379	241	64
Net periodic (benefit)	(3,848)	2,056	(334)
Post-retirement Benefits [Member]
Net periodic benefit cost [Abstract]
Service cost	0	0	0
Interest cost	44	57	70
Expected return on plan assets	0	0	0
Plan amendment	0	0	0
Amortization of unrecognized net loss	45	40	38
Amortization of prior service cost	(179)	(179)	(179)
Net periodic (benefit)	$ (90)	$ (82)	$ (71)

BENEFIT PLANS - Weighted-aver_2

BENEFIT PLANS - Weighted-average Assumptions Used to Determine Net Periodic Benefit Cost (Details)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Pension Benefits [Member]
Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Discount rate	2.80%	3.50%	4.50%
Expected return on plan assets	7.00%	7.00%	7.00%
Rate of compensation increase	3.50%	3.50%	3.50%
while employed
Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Interest credting rates	6.00%	6.00%	6.00%
after termination
Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Interest credting rates	1.42%	2.16%	3.15%
Post-retirement Benefits [Member]
Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Discount rate	2.80%	3.60%	4.45%

BENEFIT PLANS - Estimated Futur

BENEFIT PLANS - Estimated Future Benefit Payments (Details) $ in Thousands	Dec. 31, 2021USD ($)
Pension Benefits [Member]
Estimated Future Benefit Payments [Abstract]
2022	$ 10,940
2023	11,863
2024	12,185
2025	11,991
2026	13,567
2027-2031	63,874
Post-retirement Benefits [Member]
Estimated Future Benefit Payments [Abstract]
2022	151
2023	119
2024	117
2025	115
2026	113
2027-2031	$ 522

BENEFIT PLANS - Target Plan Ass

BENEFIT PLANS - Target Plan Assets Allocation (Details)	Dec. 31, 2021
Equity Securities [Member]
Plan Assets [Abstract]
Target allocation percentage of assets	60.00%
Fixed Income Securities [Member]
Plan Assets [Abstract]
Target allocation percentage of assets	40.00%

BENEFIT PLANS - Fair Value of P

BENEFIT PLANS - Fair Value of Plan Assets by Assets Category (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract]
Fair value of plan assets			$ 1,400
Total [Member]
Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract]
Fair value of plan assets	[1]	$ 290,247	270,953
Total [Member] | Quoted Prices in Active Markets For Identical Assets, Level 1
Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract]
Fair value of plan assets	[1]	284,137	258,483
Total [Member] | Significant Observable Inputs, Level 2
Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract]
Fair value of plan assets	[1]	6,110	12,470
Total [Member] | Significant Unobservable Inputs, Level 3
Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract]
Fair value of plan assets	[1]	0	0
Money Market Accounts / Cash Equivalents [Member]
Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract]
Fair value of plan assets		19,605	68,137
Money Market Accounts / Cash Equivalents [Member] | Quoted Prices in Active Markets For Identical Assets, Level 1
Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract]
Fair value of plan assets		19,605	68,137
Money Market Accounts / Cash Equivalents [Member] | Significant Observable Inputs, Level 2
Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract]
Fair value of plan assets		0	0
Money Market Accounts / Cash Equivalents [Member] | Significant Unobservable Inputs, Level 3
Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract]
Fair value of plan assets		0	0
Equity Securities [Member]
Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract]
Fair value of plan assets		169,818	143,779
Equity Securities [Member] | Quoted Prices in Active Markets For Identical Assets, Level 1
Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract]
Fair value of plan assets		169,818	137,691
Equity Securities [Member] | Significant Observable Inputs, Level 2
Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract]
Fair value of plan assets		0	6,088
Equity Securities [Member] | Significant Unobservable Inputs, Level 3
Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract]
Fair value of plan assets		0	0
U.S. Large-Cap [Member]
Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract]
Fair value of plan assets		75,180	69,195
U.S. Large-Cap [Member] | Quoted Prices in Active Markets For Identical Assets, Level 1
Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract]
Fair value of plan assets		75,180	69,195
U.S. Large-Cap [Member] | Significant Observable Inputs, Level 2
Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract]
Fair value of plan assets		0	0
U.S. Large-Cap [Member] | Significant Unobservable Inputs, Level 3
Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract]
Fair value of plan assets		0	0
U.S Mid/Small Cap [Member]
Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract]
Fair value of plan assets		12,052	17,338
U.S Mid/Small Cap [Member] | Quoted Prices in Active Markets For Identical Assets, Level 1
Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract]
Fair value of plan assets		12,052	17,338
U.S Mid/Small Cap [Member] | Significant Observable Inputs, Level 2
Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract]
Fair value of plan assets		0	0
U.S Mid/Small Cap [Member] | Significant Unobservable Inputs, Level 3
Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract]
Fair value of plan assets		0	0
CBU common stock [Member]
Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract]
Fair value of plan assets		7,604	7,701
CBU common stock [Member] | Quoted Prices in Active Markets For Identical Assets, Level 1
Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract]
Fair value of plan assets		7,604	7,701
CBU common stock [Member] | Significant Observable Inputs, Level 2
Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract]
Fair value of plan assets		0	0
CBU common stock [Member] | Significant Unobservable Inputs, Level 3
Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract]
Fair value of plan assets		0	0
International [Member]
Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract]
Fair value of plan assets		73,891	49,545
International [Member] | Quoted Prices in Active Markets For Identical Assets, Level 1
Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract]
Fair value of plan assets		73,891	43,457
International [Member] | Significant Observable Inputs, Level 2
Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract]
Fair value of plan assets		0	6,088
International [Member] | Significant Unobservable Inputs, Level 3
Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract]
Fair value of plan assets		0	0
Other
Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract]
Fair value of plan assets		1,091
Other | Quoted Prices in Active Markets For Identical Assets, Level 1
Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract]
Fair value of plan assets		1,091
Other | Significant Observable Inputs, Level 2
Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract]
Fair value of plan assets		0
Other | Significant Unobservable Inputs, Level 3
Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract]
Fair value of plan assets		0
Fixed Income Securities [Member]
Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract]
Fair value of plan assets		76,097	41,424
Fixed Income Securities [Member] | Quoted Prices in Active Markets For Identical Assets, Level 1
Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract]
Fair value of plan assets		69,987	35,042
Fixed Income Securities [Member] | Significant Observable Inputs, Level 2
Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract]
Fair value of plan assets		6,110	6,382
Fixed Income Securities [Member] | Significant Unobservable Inputs, Level 3
Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract]
Fair value of plan assets		0	0
U.S. Treasury and Agency Securities
Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract]
Fair value of plan assets		25,962	12,395
U.S. Treasury and Agency Securities | Quoted Prices in Active Markets For Identical Assets, Level 1
Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract]
Fair value of plan assets		19,988	6,154
U.S. Treasury and Agency Securities | Significant Observable Inputs, Level 2
Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract]
Fair value of plan assets		5,974	6,241
U.S. Treasury and Agency Securities | Significant Unobservable Inputs, Level 3
Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract]
Fair value of plan assets		0	0
Investment Grade Bonds [Member]
Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract]
Fair value of plan assets		41,510	23,226
Investment Grade Bonds [Member] | Quoted Prices in Active Markets For Identical Assets, Level 1
Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract]
Fair value of plan assets		41,374	23,085
Investment Grade Bonds [Member] | Significant Observable Inputs, Level 2
Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract]
Fair value of plan assets		136	141
Investment Grade Bonds [Member] | Significant Unobservable Inputs, Level 3
Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract]
Fair value of plan assets		0	0
High Yield [Member]
Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract]
Fair value of plan assets	[2]	8,625	5,803
High Yield [Member] | Quoted Prices in Active Markets For Identical Assets, Level 1
Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract]
Fair value of plan assets	[2]	8,625	5,803
High Yield [Member] | Significant Observable Inputs, Level 2
Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract]
Fair value of plan assets	[2]	0	0
High Yield [Member] | Significant Unobservable Inputs, Level 3
Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract]
Fair value of plan assets	[2]	0	0
Other Investments [Member]
Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract]
Fair value of plan assets	[3]	24,727	17,613
Other Investments [Member] | Quoted Prices in Active Markets For Identical Assets, Level 1
Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract]
Fair value of plan assets	[3]	24,727	17,613
Other Investments [Member] | Significant Observable Inputs, Level 2
Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract]
Fair value of plan assets	[3]	0	0
Other Investments [Member] | Significant Unobservable Inputs, Level 3
Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract]
Fair value of plan assets	[3]	0	0
Dividends and Interest Receivable [Member]
Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract]
Fair value of plan assets		400	200
Pension Benefits [Member]
Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract]
Fair value of plan assets		290,687	272,600	$ 227,323
Pension Plans [Abstract]
Contribution made to defined benefit pension plan by employer		3,639	7,993
Pension Benefits [Member] | Unfunded Plan Member
Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract]
Fair value of plan assets		3,500
Pension Benefits [Member] | Nonqualified Plan [Member] | Unfunded Plan Member
Pension Plans [Abstract]
Contribution made to defined benefit pension plan by employer		$ 2,900	$ 3,900
[1]	Excludes dividends and interest receivable totaling $0.4 million and $0.2 million at December 31, 2021 and 2020, respectively.
[2]	This category is exchange-traded funds representing a diversified index of high yield corporate bonds.
[3]	This category is comprised of exchange-traded funds and mutual funds holding non-traditional investment classes including private equity funds and alternative exchange funds.

BENEFIT PLANS - 401(K) Employee

BENEFIT PLANS - 401(K) Employee Stock Ownership Plan (Details) - 401(k) Employee Stock Ownership Plan [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Defined Contribution Plan Disclosure [Line Items]
Percentage of first eligible compensation fully matched by employer	3.00%
Percentage of matching contribution in the form of common stock	100.00%
Percentage of the next eligible compensation matched at 50% by employer	3.00%
Percentage of matching contributions for the next eligible compensation in the form of company stock	50.00%
(Income)/expense recognized under plan	$ 6.9	$ 6.3	$ 6.1
Interest credit contribution expense recognized for 401(k) plan	$ 1.1	$ 0.9	$ 1.1
Minimum
Defined Contribution Plan Disclosure [Line Items]
Contribution from eligible compensation	1.00%
Maximum
Defined Contribution Plan Disclosure [Line Items]
Contribution from eligible compensation	90.00%

BENEFIT PLANS - Other Deferred

BENEFIT PLANS - Other Deferred Compensation Arrangements (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Deferred Compensation Arrangements [Abstract]
Deferred compensation arrangements (146,860 shares at December 31, 2021 and 161,457 shares at December 31, 2020)	$ 8,362	$ 9,127
Other Deferred Compensation Arrangements [Member]
Deferred Compensation Arrangements [Abstract]
Deferred compensation arrangements (146,860 shares at December 31, 2021 and 161,457 shares at December 31, 2020)	5,100	5,400
Expense recognized under plan	$ 200	$ 400	$ 200

BENEFIT PLANS - Deferred Compen

BENEFIT PLANS - Deferred Compensation Plans for Directors (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Deferred Compensation Arrangements [Abstract]
Liability accrued for compensation plan	$ 8,362	$ 9,127
Deferred Compensation Plans for Directors [Member] | Directors [Member]
Deferred Compensation Arrangements [Abstract]
Deferred compensation arrangement with individual, shares credited (in shares)	137,945	141,655
Liability accrued for compensation plan	$ 5,100	$ 4,800
Expense recognized under plan	$ 200	$ 200	$ 200

STOCK-BASED COMPENSATION PLAN_2

STOCK-BASED COMPENSATION PLANS - Long-Term Incentive Program (Details) - shares	May 17, 2017	May 14, 2014	May 25, 2011	Dec. 31, 2021
Share-based Arrangements with Employees and Nonemployees
Shares of common stock authorized for stock-based compensation plan (in shares)				4,000,000
Additional shares of common stock authorized for stock-based compensation plan (in shares)	1,000,000	1,000,000	900,000
Number of shares available for grant (in shares)				600,000
Stock Options [Member]
Share-based Arrangements with Employees and Nonemployees
Term of options				10 years
Award vesting period				5 years
Director's Stock Balance Plan [Member] | Nonqualified Stock Option [Member]
Share-based Arrangements with Employees and Nonemployees
Term of options				1 year
Term of options in event of death				2 years

STOCK-BASED COMPENSATION PLAN_3

STOCK-BASED COMPENSATION PLANS - Activity in Long-Term Incentive Program (Details) - Stock Options [Member] - $ / shares	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Options, Outstanding [Roll Forward]
Outstanding, beginning of period (in shares)	1,542,259	1,502,994
Granted (in shares)	168,976	254,496
Exercised (in shares)	(310,423)	(197,564)
Forfeited (in shares)	(8,107)	(17,667)
Outstanding, end of period (in shares)	1,392,705	1,542,259
Exercisable, end of period (in shares)	879,074
Weighted-average exercise price of shares [Abstract]
Outstanding, beginning of period (in dollars per share)	$ 45.49	$ 42.82
Granted (in dollars per share)	79.68	51.68
Exercised (in dollars per share)	40.17	32.65
Forfeited (in dollars per share)	61.56	50.97
Outstanding, end of period (in dollars per share)	50.73	$ 45.49
Exercisable, end of period (in dollars per share)	$ 43.84

STOCK-BASED COMPENSATION PLAN_4

STOCK-BASED COMPENSATION PLANS - Summary of Stock Options Outstanding (Details) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2021USD ($)$ / sharesshares
Options [Abstract]
Options outstanding, shares (in shares) | shares	1,392,705
Options outstanding, weighted-average exercise price (in dollars per share)	$ 50.73
Options outstanding, weighted-average remaining life	5 years 9 months 21 days
Options exercisable, shares (in shares) | shares	879,074
Options exercisable, weighted-average exercise price (in dollars per share)	$ 43.84
Weighted-average remaining contractual term of outstanding stock options	5 years 9 months 21 days
Weighted-average remaining contractual term of outstanding and exercisable stock options	4 years 6 months 21 days
Aggregate intrinsic value of outstanding stock options | $	$ 33.9
Aggregate intrinsic value of exercisable stock options | $	$ 27
$0.00 - $29.00
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Additional Disclosures [Abstract]
Exercise price range, lower range limit (in dollars per share)	$ 0
Exercise price range, upper range limit (in dollars per share)	$ 29
Options [Abstract]
Options outstanding, shares (in shares) | shares	57,354
Options outstanding, weighted-average exercise price (in dollars per share)	$ 24.78
Options outstanding, weighted-average remaining life	3 years 6 months 18 days
Options exercisable, shares (in shares) | shares	57,354
Options exercisable, weighted-average exercise price (in dollars per share)	$ 24.78
$29.01 - $30.00
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Additional Disclosures [Abstract]
Exercise price range, lower range limit (in dollars per share)	29.01
Exercise price range, upper range limit (in dollars per share)	$ 30
Options [Abstract]
Options outstanding, shares (in shares) | shares	58,276
Options outstanding, weighted-average exercise price (in dollars per share)	$ 29.79
Options outstanding, weighted-average remaining life	1 year 2 months 15 days
Options exercisable, shares (in shares) | shares	58,276
Options exercisable, weighted-average exercise price (in dollars per share)	$ 29.79
$30.01 - $40.00
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Additional Disclosures [Abstract]
Exercise price range, lower range limit (in dollars per share)	30.01
Exercise price range, upper range limit (in dollars per share)	$ 40
Options [Abstract]
Options outstanding, shares (in shares) | shares	403,901
Options outstanding, weighted-average exercise price (in dollars per share)	$ 37.07
Options outstanding, weighted-average remaining life	3 years 5 months 15 days
Options exercisable, shares (in shares) | shares	403,901
Options exercisable, weighted-average exercise price (in dollars per share)	$ 37.07
$40.01 - $60.00
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Additional Disclosures [Abstract]
Exercise price range, lower range limit (in dollars per share)	40.01
Exercise price range, upper range limit (in dollars per share)	$ 60
Options [Abstract]
Options outstanding, shares (in shares) | shares	706,389
Options outstanding, weighted-average exercise price (in dollars per share)	$ 55.54
Options outstanding, weighted-average remaining life	6 years 10 months 28 days
Options exercisable, shares (in shares) | shares	352,515
Options exercisable, weighted-average exercise price (in dollars per share)	$ 56.30
$60.01 - $80.00
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Additional Disclosures [Abstract]
Exercise price range, lower range limit (in dollars per share)	60.01
Exercise price range, upper range limit (in dollars per share)	$ 80
Options [Abstract]
Options outstanding, shares (in shares) | shares	166,785
Options outstanding, weighted-average exercise price (in dollars per share)	$ 79.68
Options outstanding, weighted-average remaining life	9 years 2 months 19 days
Options exercisable, shares (in shares) | shares	7,028
Options exercisable, weighted-average exercise price (in dollars per share)	$ 79.66

STOCK-BASED COMPENSATION PLAN_5

STOCK-BASED COMPENSATION PLANS - Stock-Based Compensation Expense Recognized (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Stock Options [Member]
Compensation Related Costs [Abstract]
Stock-based compensation expense related to incentive and non-qualified stock options recognized	$ 2.6	$ 2.7	$ 2.2
Income tax benefit recognized	0.6	0.7	0.5
Restricted Stock [Member]
Compensation Related Costs [Abstract]
Stock-based compensation expense related to incentive and non-qualified stock options recognized	$ 3.3	$ 3.3	$ 2.8

STOCK-BASED COMPENSATION PLAN_6

STOCK-BASED COMPENSATION PLANS - Assumptions Used to Estimate Value of Stock Options (Details) - $ / shares	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
STOCK-BASED COMPENSATION PLANS
Fair value assumptions, method used	Black-Scholes option-pricing model
Weighted-average Fair Value of Options Granted (in dollars per share)	$ 18.43	$ 10.86	$ 14.16
Assumptions [Abstract]
Weighted-average expected life	6 years 6 months	6 years 6 months	6 years 6 months
Future dividend yield	2.48%	2.57%	2.73%
Share price volatility	30.09%	29.29%	29.31%
Weighted-average risk-free interest rate	1.28%	0.67%	2.44%

STOCK-BASED COMPENSATION PLAN_7

STOCK-BASED COMPENSATION PLANS - Unrecognized Stock-Based Compensation Expense and Stock Option Exercises (Details) - Stock Options [Member] - USD ($) shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Unrecognized Stock-Based Compensation Expense and Stock Option Exercises
Unrecognized stock-based compensation expense related to non-vested stock options	$ 5.5
Weighted average period for recognition of unrecognized compensation cost	3 years 3 months 18 days
Total fair value of stock options vested	$ 2.5	$ 2.5	$ 2.4
Proceeds from stock option exercises	14.2	7.5
Related tax benefits from stock option exercises	$ 1.8	$ 1.2
Shares issued in connection with stock option exercise (in shares)	0.3	0.2
Total intrinsic value of options exercised	$ 10.3	$ 6.6	$ 11.6

STOCK-BASED COMPENSATION PLAN_8

STOCK-BASED COMPENSATION PLANS - Activity of Unvested Restricted Stock Awards (Details) - Restricted Stock [Member] - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Restricted Shares
Unvested, beginning of period (in shares)	176,408	196,788
Awards (in shares)	51,456	52,132
Forfeitures (in shares)	(2,619)	(12,884)
Vestings (in shares)	(47,977)	(59,628)
Unvested, end of period (in shares)	177,268	176,408	196,788
Weighted-average grant date fair value
Unvested, beginning of period (in dollars per share)	$ 47.24	$ 45.58
Awards (in dollars per share)	79.51	51.64
Forfeitures (in dollars per share)	54.15	37.14
Vestings (in dollars per share)	52.84	47.80
Unvested, end of period (in dollars per share)	$ 54.98	$ 47.24	$ 45.58
Unrecognized stock-based compensation expense	$ 7.1
Award vesting period	5 years
Weighted-average period for recognition of unrecognized compensation cost	3 years 8 months 12 days
Total fair value of restricted stock vested	$ 2.5	$ 2.9	$ 3.8

EARNINGS PER SHARE (Details)

EARNINGS PER SHARE (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
EARNINGS PER SHARE
Weighted-average anti-dilutive stock options outstanding (in shares)	100,000	600,000	500,000
Basic earnings per share
Net income	$ 189,694	$ 164,676	$ 169,063
Income attributable to unvested stock-based compensation awards	(445)	(514)	(400)
Income available to common shareholders	$ 189,249	$ 164,162	$ 168,663
Weighted-average common shares outstanding - basic (in shares)	53,977,000	52,969,000	51,732,000
Basic earnings per share (in dollars per share)	$ 3.51	$ 3.10	$ 3.26
Diluted earnings per share
Net income	$ 189,694	$ 164,676	$ 169,063
Income attributable to unvested stock-based compensation awards	(445)	(514)	(400)
Income available to common shareholders	$ 189,249	$ 164,162	$ 168,663
Weighted-average common shares outstanding (in shares)	53,977,000	52,969,000	51,732,000
Assumed exercise of stock options (in shares)	423,000	352,000	516,000
Weighted-average common shares outstanding - diluted (in shares)	54,400,000	53,321,000	52,248,000
Diluted earnings per share (in dollars per share)	$ 3.48	$ 3.08	$ 3.23
Cash dividends declared per share (in dollars per share)	$ 1.70	$ 1.66	$ 1.58
Stock Repurchase Program
Number of common shares authorized to be repurchased (in shares)	2,697,000	2,680,000
Number of common shares repurchased (in shares)	67,500

COMMITMENTS, CONTINGENT LIABI_3

COMMITMENTS, CONTINGENT LIABILITIES AND RESTRICTIONS (Details) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
COMMITMENTS, CONTINGENT LIABILITIES AND RESTRICTIONS.
Contract amount of commitments and contingencies	$ 1,486,563,000	$ 1,352,781,000
Unused lines of credit	25,000,000
Federal Home Loan Bank unused borrowing capacity	1,710,000,000
Federal Reserve unused borrowing capacity	247,700,000
Federal Reserve required average total reserve	0	0
Litigation accrual	(100,000)	2,950,000	$ 0
Litigation settlement amount	2,900,000
Adjustment to the Company's litigation accrual	100,000
Minimum
COMMITMENTS, CONTINGENT LIABILITIES AND RESTRICTIONS.
Range of reasonably possible losses for such matters in the aggregate, beyond the existing recorded liability	0
Maximum
COMMITMENTS, CONTINGENT LIABILITIES AND RESTRICTIONS.
Range of reasonably possible losses for such matters in the aggregate, beyond the existing recorded liability	1,000,000
Commitments to Extend Credit
COMMITMENTS, CONTINGENT LIABILITIES AND RESTRICTIONS.
Contract amount of commitments and contingencies	1,443,879,000	1,313,568,000
Standby Letters of Credit
COMMITMENTS, CONTINGENT LIABILITIES AND RESTRICTIONS.
Contract amount of commitments and contingencies	$ 42,684,000	$ 39,213,000

LEASES (Details)

LEASES (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Operating Leases
Term of option to terminate		1 year
Components of Lease Expense
Operating lease cost		$ 8,397	$ 9,000	$ 8,724
Variable lease cost		50	53	18
Short-term lease cost	[1]	148	369	240
Total lease cost		8,595	9,422	$ 8,982
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash outflows for operating leases		8,203	8,478
Right-of-use assets obtained in exchange for lease obligations:
Operating leases		5,344	3,519
Operating leases
Operating lease right-of-use assets		$ 31,754	$ 34,908
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]		Property, Plant and Equipment, Net	Property, Plant and Equipment, Net
Operating lease liabilities		$ 32,833	$ 35,857
Operating Lease, Liability, Statement of Financial Position [Extensible List]		Operating lease liabilities	Operating lease liabilities
Weighted average remaining lease term
Operating leases		5 years 4 months 24 days	6 years 1 month 6 days
Weighted average discount rate
Operating leases		2.62%	2.82%
Minimum
Operating Leases
Remaining term of lease		1 year
Term of option to extend		1 year
Maximum
Operating Leases
Remaining term of lease		13 years
Term of option to extend		40 years
[1]	Short-term lease cost includes the cost of leases with terms of twelve months or less, excluding leases with terms of one month or less.

LEASES, Maturities of Lease Lia

LEASES, Maturities of Lease Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Maturities of Lease Liabilities:
2022	$ 8,729	$ 8,697
2023	7,640	7,505
2024	5,920	6,336
2025	4,401	4,973
2026	3,062	3,688
Thereafter	5,846	8,222
Total lease payments	35,598	39,421
Less imputed interest	(2,765)	(3,564)
Total	32,833	35,857
Operating lease right-of-use assets	$ 31,754	$ 34,908
Weighted average remaining lease term operating lease	5 years 4 months 24 days	6 years 1 month 6 days
Weighted average discount rate operating lease	2.62%	2.82%
706 North Clinton [Member]
Maturities of Lease Liabilities:
2022	$ 591	$ 591
2023	591	591
2024	591	591
2025	605	591
2026	614	605
Thereafter	1,727	2,341
Total lease payments	4,719	5,310
Less imputed interest	(633)	(791)
Total	$ 4,086	4,519
Membership interest	50.00%
Operating lease right-of-use assets	$ 4,000	$ 4,500
Weighted average remaining lease term operating lease	8 years	9 years
Weighted average discount rate operating lease	3.68%	3.68%

REGULATORY MATTERS (Details)

REGULATORY MATTERS (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Tier 1 Leverage ratio [Abstract]
Required capital conservation ratio	2.50%	2.50%
Tier 1 Leverage ratio, actual amount	$ 1,331,368	$ 1,314,864
Tier 1 Leverage ratio, actual ratio	9.09	10.16
Tier 1 leverage ratio for capital adequacy purposes, amount	$ 585,594	$ 517,736
Tier 1 leverage ratio for capital adequacy purposes, ratio	4	4
Tier 1 leverage capital to be well-capitalized under prompt corrective action, amount	$ 731,993	$ 647,169
Tier 1 leverage capital to be well-capitalized under prompt corrective action, ratio	5	5
Tier 1 risk-based capital [Abstract]
Tier 1 risk-based capital, actual amount	$ 1,331,368	$ 1,314,864
Tier 1 risk-based capital, actual ratio	18.60	18.99
Tier 1 risk-based capital for capital adequacy purposes, amount	$ 429,559	$ 415,472
Tier 1 risk-based capital for capital adequacy purposes, ratio	6	6
Tier 1 risk-based capital for capital adequacy purposes plus capital conservation buffer, amount	$ 608,542	$ 588,585
Tier 1 risk-based capital for capital adequacy purposes plus capital conservation buffer, ratio	8.50%	8.50%
Tier 1 risk based capital to be well-capitalized under prompt corrective action, amount	$ 572,746	$ 553,962
Tier 1 risk-based capital to be well-capitalized under prompt corrective action, ratio	8	8
Total risk-based capital [Abstract]
Total risk-based capital, actual amount	$ 1,380,458	$ 1,375,704
Total risk-based capital, actual ratio	19.28	19.87
Total risk-based capital for capital adequacy purposes, amount	$ 572,746	$ 553,962
Total risk-based capita for capital adequacy purposes, ratio	8	8
Total risk-based capital for capital adequacy purposes plus capital conservation buffer, amount	$ 751,729	$ 727,075
Total risk-based capita for capital adequacy purposes plus capital conservation buffer, ratio	10.50%	10.50%
Total risk based capital to be well-capitalized under prompt corrective action, amount	$ 715,932	$ 692,453
Total risk based capital to be well-capitalized under prompt corrective action, ratio	10	10
Common equity Tier 1 capital [Abstract]
Common equity Tier 1 capital, actual amount	$ 1,331,259	$ 1,239,754
Common equity Tier 1 capital, actual ratio	18.60	17.90
Common equity Tier 1 capital for capital adequacy purposes, amount	$ 322,169	$ 311,604
Common equity Tier 1 capital for capital adequacy purposes, ratio	4.50%	4.50%
Common equity Tier 1 capital for capital adequacy purposes plus capital conservation buffer, amount	$ 501,152	$ 484,717
Common equity Tier 1 capital for capital adequacy purposes plus capital conservation buffer, ratio	7.00%	7.00%
Common equity Tier 1 capital to be well-capitalized under prompt corrective action, amount	$ 465,356	$ 450,094
Common equity Tier 1 capital to be well-capitalized under prompt corrective action, ratio	6.50%	6.50%
Community Bank, N.A. [Member]
Tier 1 Leverage ratio [Abstract]
Tier 1 Leverage ratio, actual amount	$ 1,058,091	$ 1,028,285
Tier 1 Leverage ratio, actual ratio	7.26	7.98
Tier 1 leverage ratio for capital adequacy purposes, amount	$ 582,631	$ 515,552
Tier 1 leverage ratio for capital adequacy purposes, ratio	4	4
Tier 1 leverage capital to be well-capitalized under prompt corrective action, amount	$ 728,289	$ 644,440
Tier 1 leverage capital to be well-capitalized under prompt corrective action, ratio	5	5
Tier 1 risk-based capital [Abstract]
Tier 1 risk-based capital, actual amount	$ 1,058,091	$ 1,028,285
Tier 1 risk-based capital, actual ratio	14.92	14.98
Tier 1 risk-based capital for capital adequacy purposes, amount	$ 425,393	$ 411,880
Tier 1 risk-based capital for capital adequacy purposes, ratio	6	6
Tier 1 risk-based capital for capital adequacy purposes plus capital conservation buffer, amount	$ 602,640	$ 583,497
Tier 1 risk-based capital for capital adequacy purposes plus capital conservation buffer, ratio	8.50%	8.50%
Tier 1 risk based capital to be well-capitalized under prompt corrective action, amount	$ 567,190	$ 549,174
Tier 1 risk-based capital to be well-capitalized under prompt corrective action, ratio	8	8
Total risk-based capital [Abstract]
Total risk-based capital, actual amount	$ 1,107,181	$ 1,089,125
Total risk-based capital, actual ratio	15.62	15.87
Total risk-based capital for capital adequacy purposes, amount	$ 567,190	$ 549,174
Total risk-based capita for capital adequacy purposes, ratio	8	8
Total risk-based capital for capital adequacy purposes plus capital conservation buffer, amount	$ 744,437	$ 720,791
Total risk-based capita for capital adequacy purposes plus capital conservation buffer, ratio	10.50%	10.50%
Total risk based capital to be well-capitalized under prompt corrective action, amount	$ 708,988	$ 686,467
Total risk based capital to be well-capitalized under prompt corrective action, ratio	10	10
Common equity Tier 1 capital [Abstract]
Common equity Tier 1 capital, actual amount	$ 1,057,982	$ 1,028,175
Common equity Tier 1 capital, actual ratio	14.92	14.98
Common equity Tier 1 capital for capital adequacy purposes, amount	$ 319,045	$ 308,910
Common equity Tier 1 capital for capital adequacy purposes, ratio	4.50%	4.50%
Common equity Tier 1 capital for capital adequacy purposes plus capital conservation buffer, amount	$ 496,292	$ 480,527
Common equity Tier 1 capital for capital adequacy purposes plus capital conservation buffer, ratio	7.00%	7.00%
Common equity Tier 1 capital to be well-capitalized under prompt corrective action, amount	$ 460,842	$ 446,204
Common equity Tier 1 capital to be well-capitalized under prompt corrective action, ratio	6.50%	6.50%

PARENT COMPANY STATEMENTS - Con

PARENT COMPANY STATEMENTS - Condensed Statements of Condition (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Assets:
Cash and cash equivalents	$ 1,875,064	$ 1,645,805
Investment in and advances to:
Other assets	313,854	281,903
Total assets	15,552,657	13,931,094	$ 11,410,295
Liabilities and shareholders' equity:
Accrued interest and other liabilities	210,797	230,724
Borrowings	0	77,320
Shareholders' equity	2,100,807	2,104,107	$ 1,855,234	$ 1,713,783
Total liabilities and shareholders' equity	15,552,657	13,931,094
Parent Company
Assets:
Cash and cash equivalents	154,374	196,021
Investment securities	8,679	6,043
Investment in and advances to:
Bank subsidiary	1,721,520	1,802,150
Non-bank subsidiaries	232,096	196,090
Other assets	18,462	15,290
Total assets	2,135,131	2,215,594
Liabilities and shareholders' equity:
Accrued interest and other liabilities	31,047	30,864
Borrowings	3,277	80,623
Shareholders' equity	2,100,807	2,104,107
Total liabilities and shareholders' equity	$ 2,135,131	$ 2,215,594

PARENT COMPANY STATEMENTS - C_2

PARENT COMPANY STATEMENTS - Condensed Statements of Income (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Expenses:
Interest on borrowings	$ 293	$ 1,875	$ 3,898
Acquisition expenses	701	4,933	8,608
Gain on debt extinguishment	0	(421)	0
Other expenses	18,500	18,415	24,090
Income before tax benefit and equity in undistributed net income of subsidiaries	241,348	206,076	209,338
Income tax benefit	(51,654)	(41,400)	(40,275)
Net income	189,694	164,676	169,063
Other comprehensive (loss) income, net of tax:
Changes in other comprehensive income (loss) related to pension and other post retirement obligations	13,403	6,009	(2,045)
Changes in other comprehensive (loss) income related to unrealized losses on available-for-sale securities	(126,107)	66,294	37,124
Other comprehensive (loss) income	(112,704)	72,303	35,079
Comprehensive income	76,990	236,979	204,142
Parent Company
Dividends from subsidiaries:
Bank subsidiary	125,000	105,000	115,000
Non-bank subsidiaries	14,000	13,500	27,600
Interest and dividends on investments	245	168	134
Total revenues	139,245	118,668	142,734
Expenses:
Interest on borrowings	446	2,546	4,244
Acquisition expenses	0	450	1,248
Gain on debt extinguishment	0	(421)	0
Other expenses	5,717	4,945	477
Total expenses	6,163	7,520	5,969
Income before tax benefit and equity in undistributed net income of subsidiaries	133,082	111,148	136,765
Income tax benefit	3,964	3,739	4,545
Income before equity in undistributed net income of subsidiaries	137,046	114,887	141,310
Equity in undistributed net income of subsidiaries	52,648	49,789	27,753
Net income	189,694	164,676	169,063
Other comprehensive (loss) income, net of tax:
Changes in other comprehensive income (loss) related to pension and other post retirement obligations	13,403	6,009	(2,045)
Changes in other comprehensive (loss) income related to unrealized losses on available-for-sale securities	(126,107)	66,294	37,124
Other comprehensive (loss) income	(112,704)	72,303	35,079
Comprehensive income	$ 76,990	$ 236,979	$ 204,142

PARENT COMPANY STATEMENTS - C_3

PARENT COMPANY STATEMENTS - Condensed Statements of Cash Flows (Details) - USD ($) $ in Thousands	Sep. 18, 2019	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Operating activities:
Net income		$ 189,694	$ 164,676	$ 169,063
Adjustments to reconcile net income to net cash provided by operating activities
Net change in other assets and other liabilities		2,064	(16,939)	2,545
Net cash provided by operating activities		202,546	179,483	202,502
Investing activities:
Cash paid for acquisitions, net of cash acquired of $0, $448, and $1,328, respectively	$ (500)	(29,329)	34,360	(4,653)
Net cash used in investing activities		(1,530,775)	(398,720)	(157,054)
Financing activities:
Issuance of common stock		9,821	15,792	6,915
Purchase of treasury stock		(5,106)	(271)	(286)
Sale of treasury stock		0	85	6,884
Increase in deferred compensation arrangements		252	271	286
Net cash provided by (used in) financing activities		1,557,488	1,660,012	(52,252)
Change in cash and cash equivalents		229,259	1,440,775	(6,804)
Cash and cash equivalents at beginning of year		1,645,805	205,030	211,834
Cash and cash equivalents at end of year		1,875,064	1,645,805	205,030
Supplemental disclosures of cash flow information:
Cash paid for interest		13,752	21,169	25,425
Supplemental disclosures of noncash financing activities
Dividends declared and unpaid		23,235	22,695	21,342
Common stock issued for acquisition		0	76,942	0
Parent Company
Operating activities:
Net income		189,694	164,676	169,063
Adjustments to reconcile net income to net cash provided by operating activities
Equity in undistributed net income of subsidiaries		(52,648)	(49,789)	(27,753)
Net change in other assets and other liabilities		(3,050)	1,740	86
Net cash provided by operating activities		133,996	116,627	141,396
Investing activities:
Purchases of investment securities		(5,173)	(3,000)	0
Cash paid for acquisitions, net of cash acquired of $0, $448, and $1,328, respectively		0	(20,892)	(92,056)
(Capital contributions to)/Return of capital from		(12,918)	2	100,680
Net cash used in investing activities		(18,091)	(23,890)	8,624
Financing activities:
Repayment of advances from subsidiaries		(482)	(482)	(1,652)
Repayment of borrowings		(77,320)	(12,062)	(22,681)
Issuance of common stock		16,155	22,211	12,200
Purchase of treasury stock		(5,106)	(271)	(286)
Sale of treasury stock		0	85	6,884
Increase in deferred compensation arrangements		252	271	286
Cash dividends paid		(91,051)	(87,131)	(80,241)
Net cash provided by (used in) financing activities		(157,552)	(77,379)	(85,490)
Change in cash and cash equivalents		(41,647)	15,358	64,530
Cash and cash equivalents at beginning of year		196,021	180,663	116,133
Cash and cash equivalents at end of year		154,374	196,021	180,663
Supplemental disclosures of cash flow information:
Cash paid for interest		560	2,555	4,306
Supplemental disclosures of noncash financing activities
Dividends declared and unpaid		23,235	22,695	21,342
Advances from subsidiaries		482	932	1,691
Common stock issued for acquisition		$ 0	$ 76,942	$ 0

PARENT COMPANY STATEMENTS - C_4

PARENT COMPANY STATEMENTS - Condensed Statements of Cash Flows (Parenthetical) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Statements of Cash Flows
Cash paid for acquisitions	$ 541	$ 55,973	$ 90,381
Parent Company
Statements of Cash Flows
Cash paid for acquisitions	$ 0	$ 448	$ 1,328

FAIR VALUE - Financial Assets a

FAIR VALUE - Financial Assets and Liabilities Accounted for at Fair Value On a Recurring Basis (Details) - USD ($)	Dec. 31, 2021	Dec. 31, 2020
Available-for-sale investment securities
Available-for-sale investment securities	$ 4,934,210,000
Equity securities	463,000	$ 445,000
U.S. Treasury and Agency Securities
Available-for-sale investment securities
Available-for-sale investment securities	3,998,564,000	2,501,382,000
Obligations of State and Political Subdivisions
Available-for-sale investment securities
Available-for-sale investment securities	430,289,000	475,660,000
Government Agency Mortgage-Backed Securities
Available-for-sale investment securities
Available-for-sale investment securities	477,056,000	522,638,000
Corporate debt securities
Available-for-sale investment securities
Available-for-sale investment securities	7,962,000	4,635,000
Government Agency Collateralized Mortgage Obligations
Available-for-sale investment securities
Available-for-sale investment securities	20,339,000	43,577,000
Significant Unobservable Inputs, Level 3 | Commitments to Originate Real Estate Loans for Sale
Available-for-sale investment securities
Derivative asset	51,000	14,000
Recurring
Available-for-sale investment securities
Available-for-sale investment securities	4,934,210,000	3,547,892,000
Equity securities	463,000	445,000
Mortgage loans held for sale		1,622,000
Total	4,935,049,000	3,550,473,000
Recurring | Interest Rate Swap Agreements
Available-for-sale investment securities
Derivative asset	296,000	1,572,000
Derivative liability	(3,000)	(1,074,000)
Recurring | ForwardContractsMember
Available-for-sale investment securities
Derivative asset		2,000
Derivative liability	32,000
Recurring | Commitments to Originate Real Estate Loans for Sale
Available-for-sale investment securities
Derivative asset	51,000	14,000
Recurring | U.S. Treasury and Agency Securities
Available-for-sale investment securities
Available-for-sale investment securities	3,998,564,000	2,501,382,000
Recurring | Obligations of State and Political Subdivisions
Available-for-sale investment securities
Available-for-sale investment securities	430,289,000	475,660,000
Recurring | Government Agency Mortgage-Backed Securities
Available-for-sale investment securities
Available-for-sale investment securities	477,056,000	522,638,000
Recurring | Corporate debt securities
Available-for-sale investment securities
Available-for-sale investment securities	7,962,000	4,635,000
Recurring | Government Agency Collateralized Mortgage Obligations
Available-for-sale investment securities
Available-for-sale investment securities	20,339,000	43,577,000
Recurring | Quoted Prices in Active Markets For Identical Assets, Level 1
Available-for-sale investment securities
Available-for-sale investment securities	3,900,924,000	2,359,912,000
Equity securities	463,000	445,000
Mortgage loans held for sale		0
Total	3,901,387,000	2,360,357,000
Recurring | Quoted Prices in Active Markets For Identical Assets, Level 1 | Interest Rate Swap Agreements
Available-for-sale investment securities
Derivative asset	0	0
Derivative liability	0	0
Recurring | Quoted Prices in Active Markets For Identical Assets, Level 1 | ForwardContractsMember
Available-for-sale investment securities
Derivative asset		0
Derivative liability	0
Recurring | Quoted Prices in Active Markets For Identical Assets, Level 1 | Commitments to Originate Real Estate Loans for Sale
Available-for-sale investment securities
Derivative asset	0	0
Recurring | Quoted Prices in Active Markets For Identical Assets, Level 1 | U.S. Treasury and Agency Securities
Available-for-sale investment securities
Available-for-sale investment securities	3,900,924,000	2,359,912,000
Recurring | Quoted Prices in Active Markets For Identical Assets, Level 1 | Obligations of State and Political Subdivisions
Available-for-sale investment securities
Available-for-sale investment securities	0	0
Recurring | Quoted Prices in Active Markets For Identical Assets, Level 1 | Government Agency Mortgage-Backed Securities
Available-for-sale investment securities
Available-for-sale investment securities	0	0
Recurring | Quoted Prices in Active Markets For Identical Assets, Level 1 | Corporate debt securities
Available-for-sale investment securities
Available-for-sale investment securities	0	0
Recurring | Quoted Prices in Active Markets For Identical Assets, Level 1 | Government Agency Collateralized Mortgage Obligations
Available-for-sale investment securities
Available-for-sale investment securities	0	0
Recurring | Significant Observable Inputs, Level 2
Available-for-sale investment securities
Available-for-sale investment securities	1,033,286,000	1,187,980,000
Equity securities	0	0
Mortgage loans held for sale	0	1,622,000
Total	1,033,611,000	1,190,102,000
Recurring | Significant Observable Inputs, Level 2 | Interest Rate Swap Agreements
Available-for-sale investment securities
Derivative asset	296,000	1,572,000
Derivative liability	(3,000)	(1,074,000)
Recurring | Significant Observable Inputs, Level 2 | ForwardContractsMember
Available-for-sale investment securities
Derivative asset		2,000
Derivative liability	32,000
Recurring | Significant Observable Inputs, Level 2 | Commitments to Originate Real Estate Loans for Sale
Available-for-sale investment securities
Derivative asset	0	0
Recurring | Significant Observable Inputs, Level 2 | U.S. Treasury and Agency Securities
Available-for-sale investment securities
Available-for-sale investment securities	97,640,000	141,470,000
Recurring | Significant Observable Inputs, Level 2 | Obligations of State and Political Subdivisions
Available-for-sale investment securities
Available-for-sale investment securities	430,289,000	475,660,000
Recurring | Significant Observable Inputs, Level 2 | Government Agency Mortgage-Backed Securities
Available-for-sale investment securities
Available-for-sale investment securities	477,056,000	522,638,000
Recurring | Significant Observable Inputs, Level 2 | Corporate debt securities
Available-for-sale investment securities
Available-for-sale investment securities	7,962,000	4,635,000
Recurring | Significant Observable Inputs, Level 2 | Government Agency Collateralized Mortgage Obligations
Available-for-sale investment securities
Available-for-sale investment securities	20,339,000	43,577,000
Recurring | Significant Unobservable Inputs, Level 3
Available-for-sale investment securities
Available-for-sale investment securities	0	0
Equity securities	0	0
Mortgage loans held for sale		0
Total	51,000	14,000
Recurring | Significant Unobservable Inputs, Level 3 | Interest Rate Swap Agreements
Available-for-sale investment securities
Derivative asset	0	0
Derivative liability	0	0
Recurring | Significant Unobservable Inputs, Level 3 | ForwardContractsMember
Available-for-sale investment securities
Derivative asset		0
Derivative liability	0
Recurring | Significant Unobservable Inputs, Level 3 | Commitments to Originate Real Estate Loans for Sale
Available-for-sale investment securities
Derivative asset	51,000	14,000
Recurring | Significant Unobservable Inputs, Level 3 | U.S. Treasury and Agency Securities
Available-for-sale investment securities
Available-for-sale investment securities	0	0
Recurring | Significant Unobservable Inputs, Level 3 | Obligations of State and Political Subdivisions
Available-for-sale investment securities
Available-for-sale investment securities	0	0
Recurring | Significant Unobservable Inputs, Level 3 | Government Agency Mortgage-Backed Securities
Available-for-sale investment securities
Available-for-sale investment securities	0	0
Recurring | Significant Unobservable Inputs, Level 3 | Corporate debt securities
Available-for-sale investment securities
Available-for-sale investment securities	0	0
Recurring | Significant Unobservable Inputs, Level 3 | Government Agency Collateralized Mortgage Obligations
Available-for-sale investment securities
Available-for-sale investment securities	$ 0	$ 0

FAIR VALUE, Assets and Liabilit

FAIR VALUE, Assets and Liabilities Measured on Nonrecurring Basis (Details) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Assets and Liabilities Measured on Nonrecurring Basis
Mortgage servicing rights	$ 1,469,000	$ 1,384,000
Valuation allowance	566,000	3,874,000
Fair value, assets, levels transfers	0
Mortgage Servicing Rights.
Assets and Liabilities Measured on Nonrecurring Basis
Valuation allowance		200,000
Significant Unobservable Inputs, Level 3
Assets and Liabilities Measured on Nonrecurring Basis
Individually assessed loans	1,820,000	25,063,000
Other real estate owned	718,000	883,000
Mortgage servicing rights	810,000
Contingent consideration	$ (3,100,000)
Significant Unobservable Inputs, Level 3 | Other Real Estate Owned | Market Approach Valuation Technique | Minimum
Assets and Liabilities Measured on Nonrecurring Basis
Discount rate	31.80%
Significant Unobservable Inputs, Level 3 | Other Real Estate Owned | Market Approach Valuation Technique | Maximum
Assets and Liabilities Measured on Nonrecurring Basis
Discount rate	42.30%
Non-recurring
Assets and Liabilities Measured on Nonrecurring Basis
Individually assessed loans	$ 1,820,000	25,063,000
Other real estate owned	718,000	883,000
Mortgage servicing rights	810,000	682,000
Contingent consideration	(3,100,000)	0
Total	248,000	26,628,000
Non-recurring | Quoted Prices in Active Markets For Identical Assets, Level 1
Assets and Liabilities Measured on Nonrecurring Basis
Individually assessed loans	0	0
Other real estate owned	0	0
Mortgage servicing rights	0	0
Contingent consideration	0	0
Total	0	0
Non-recurring | Significant Observable Inputs, Level 2
Assets and Liabilities Measured on Nonrecurring Basis
Individually assessed loans	0	0
Other real estate owned	0	0
Mortgage servicing rights	0	0
Contingent consideration	0	0
Total	0	0
Non-recurring | Significant Unobservable Inputs, Level 3
Assets and Liabilities Measured on Nonrecurring Basis
Individually assessed loans	1,820,000	25,063,000
Other real estate owned	718,000	883,000
Mortgage servicing rights	810,000	682,000
Contingent consideration	(3,100,000)	0
Total	$ 248,000	$ 26,628,000

FAIR VALUE - Significant Unobse

FAIR VALUE - Significant Unobservable Inputs (Details)	Dec. 31, 2021USD ($)	Dec. 31, 2020USD ($)
Significant Unobservable Inputs used in determination of Fair Value of Assets Classified as Level 3
Fair value of MSRs at end of period	$ 1,469,000	$ 1,384,000
Significant Unobservable Inputs, Level 3
Significant Unobservable Inputs used in determination of Fair Value of Assets Classified as Level 3
Individually assessed loans	1,820,000	25,063,000
Other real estate owned	718,000	$ 883,000
Other real estate owned, Measurement Input [Extensible List]		Estimated Cost of Disposal/Market Adjustment
Fair value of MSRs at end of period	810,000
Mortgage servicing rights, measurement input		682,000
Contingent consideration	$ (3,100,000)
Significant Unobservable Inputs, Level 3 | Fair Value of Collateral
Significant Unobservable Inputs used in determination of Fair Value of Assets Classified as Level 3
Individually assessed loans, Valuation Technique [Extensible List]	Fair Value of Collateral	Fair Value of Collateral
Other real estate owned, Valuation Technique [Extensible List]	Fair Value of Collateral	Fair Value of Collateral
Significant Unobservable Inputs, Level 3 | Fair Value of Collateral | Estimated Cost of Disposal/Market Adjustment
Significant Unobservable Inputs used in determination of Fair Value of Assets Classified as Level 3
Individually assessed loans, Measurement Input [Extensible List]	Estimated Cost of Disposal/Market Adjustment	Estimated Cost of Disposal/Market Adjustment
Other real estate owned, Measurement Input [Extensible List]	Estimated Cost of Disposal/Market Adjustment
Significant Unobservable Inputs, Level 3 | Discounted Cash Flow
Significant Unobservable Inputs used in determination of Fair Value of Assets Classified as Level 3
Mortgage servicing rights, Valuation Technique [Extensible List]	Discounted Cash Flow	Discounted Cash Flow
Contingent consideration, Valuation Technique [Extensible List]	Discounted Cash Flow
Significant Unobservable Inputs, Level 3 | Discounted Cash Flow | Weighted Average Constant Prepayment Rate
Significant Unobservable Inputs used in determination of Fair Value of Assets Classified as Level 3
Mortgage servicing rights, Measurement Input [Extensible List]	Weighted Average Constant Prepayment Rate	Weighted Average Constant Prepayment Rate
Significant Unobservable Inputs, Level 3 | Discounted Cash Flow | Weighted Average Discount Rate
Significant Unobservable Inputs used in determination of Fair Value of Assets Classified as Level 3
Mortgage servicing rights, Measurement Input [Extensible List]	Weighted Average Discount Rate	Weighted Average Discount Rate
Contingent consideration, Measurement Input [Extensible List]	Weighted Average Discount Rate
Significant Unobservable Inputs, Level 3 | Discounted Cash Flow | Adequate Compensation
Significant Unobservable Inputs used in determination of Fair Value of Assets Classified as Level 3
Mortgage servicing rights, Measurement Input [Extensible List]	Adequate Compensation	Adequate Compensation
Significant Unobservable Inputs, Level 3 | Discounted Cash Flow | Probability Adjusted Level Of Retained Revenue
Significant Unobservable Inputs used in determination of Fair Value of Assets Classified as Level 3
Contingent consideration, Measurement Input [Extensible List]	Probability Adjusted Level Of Retained Revenue
Significant Unobservable Inputs, Level 3 | Minimum | Fair Value of Collateral | Estimated Cost of Disposal/Market Adjustment
Significant Unobservable Inputs used in determination of Fair Value of Assets Classified as Level 3
Individually assessed loans, measurement input	9	9
Other real estate owned, measurement input	31.8	11.3
Significant Unobservable Inputs, Level 3 | Minimum | Discounted Cash Flow | Weighted Average Constant Prepayment Rate
Significant Unobservable Inputs used in determination of Fair Value of Assets Classified as Level 3
Mortgage servicing rights, measurement input	6.4	9.8
Significant Unobservable Inputs, Level 3 | Minimum | Discounted Cash Flow | Weighted Average Discount Rate
Significant Unobservable Inputs used in determination of Fair Value of Assets Classified as Level 3
Mortgage servicing rights, measurement input	2.3	1.7
Contingent consideration, measurement input	1.4
Significant Unobservable Inputs, Level 3 | Minimum | Discounted Cash Flow | Probability Adjusted Level Of Retained Revenue
Significant Unobservable Inputs used in determination of Fair Value of Assets Classified as Level 3
Contingent consideration, measurement input 2	$ 3,000,000
Significant Unobservable Inputs, Level 3 | Maximum | Fair Value of Collateral | Estimated Cost of Disposal/Market Adjustment
Significant Unobservable Inputs used in determination of Fair Value of Assets Classified as Level 3
Individually assessed loans, measurement input	43.1	78.4
Other real estate owned, measurement input	42.3	52.9
Significant Unobservable Inputs, Level 3 | Maximum | Discounted Cash Flow | Weighted Average Constant Prepayment Rate
Significant Unobservable Inputs used in determination of Fair Value of Assets Classified as Level 3
Mortgage servicing rights, measurement input	15.2	18.8
Significant Unobservable Inputs, Level 3 | Maximum | Discounted Cash Flow | Weighted Average Discount Rate
Significant Unobservable Inputs used in determination of Fair Value of Assets Classified as Level 3
Mortgage servicing rights, measurement input	2.7	2.2
Contingent consideration, measurement input	1.7
Significant Unobservable Inputs, Level 3 | Maximum | Discounted Cash Flow | Probability Adjusted Level Of Retained Revenue
Significant Unobservable Inputs used in determination of Fair Value of Assets Classified as Level 3
Contingent consideration, measurement input 2	$ 5,800,000
Significant Unobservable Inputs, Level 3 | Weighted Average | Fair Value of Collateral | Estimated Cost of Disposal/Market Adjustment
Significant Unobservable Inputs used in determination of Fair Value of Assets Classified as Level 3
Individually assessed loans, measurement input	43.1	52.7
Other real estate owned, measurement input	33.3	34
Significant Unobservable Inputs, Level 3 | Weighted Average | Discounted Cash Flow | Weighted Average Constant Prepayment Rate
Significant Unobservable Inputs used in determination of Fair Value of Assets Classified as Level 3
Mortgage servicing rights, measurement input	14	17.6
Significant Unobservable Inputs, Level 3 | Weighted Average | Discounted Cash Flow | Weighted Average Discount Rate
Significant Unobservable Inputs used in determination of Fair Value of Assets Classified as Level 3
Mortgage servicing rights, measurement input	2.6	2.1
Contingent consideration, measurement input	1.5
Commitments to Originate Real Estate Loans for Sale | Significant Unobservable Inputs, Level 3
Significant Unobservable Inputs used in determination of Fair Value of Assets Classified as Level 3
Commitments to originate real estate loans for sale	$ 51,000	$ 14,000
Commitments to Originate Real Estate Loans for Sale | Significant Unobservable Inputs, Level 3 | Embedded Servicing Value
Significant Unobservable Inputs used in determination of Fair Value of Assets Classified as Level 3
Commitments to originate real estate loans for sale, measurement input	1	1
Commitments to Originate Real Estate Loans for Sale | Significant Unobservable Inputs, Level 3 | Discounted Cash Flow
Significant Unobservable Inputs used in determination of Fair Value of Assets Classified as Level 3
Commitments to originate real estate loans for sale, Valuation Technique [Extensible List]	Discounted Cash Flow	Discounted Cash Flow
Commitments to Originate Real Estate Loans for Sale | Significant Unobservable Inputs, Level 3 | Discounted Cash Flow | Embedded Servicing Value
Significant Unobservable Inputs used in determination of Fair Value of Assets Classified as Level 3
Commitments to originate real estate loans for sale, Measurement Input [Extensible List]	Embedded Servicing Value	Embedded Servicing Value
Business loans held for sale | Significant Unobservable Inputs, Level 3 | Adequate Compensation
Significant Unobservable Inputs used in determination of Fair Value of Assets Classified as Level 3
Business loans held for sale, measurement input	7	7

FAIR VALUE - Carrying Amounts a

FAIR VALUE - Carrying Amounts and Estimated Fair Values of Other Financial Instruments (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Carrying Value
Financial assets:
Net loans	$ 7,323,770	$ 7,355,083
Financial liabilities:
Deposits	12,911,168	11,224,974
Securities sold under agreement to repurchase, short-term	324,720	284,008
Other Federal Home Loan Bank borrowings	1,888	6,658
Subordinated notes payable	3,277	3,303
Subordinated debt held by unconsolidated subsidiary trusts	0	77,320
Fair Value
Financial assets:
Net loans	7,523,024	7,655,044
Financial liabilities:
Deposits	12,911,197	11,239,628
Securities sold under agreement to repurchase, short-term	324,720	284,008
Other Federal Home Loan Bank borrowings	1,907	6,758
Subordinated notes payable	3,277	3,303
Subordinated debt held by unconsolidated subsidiary trusts	$ 0	$ 77,320

DERIVATIVE INSTRUMENTS (Details

DERIVATIVE INSTRUMENTS (Details) - Interest Rate Swap Agreements - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Derivative Instruments
Derivative, notional amount	$ 0.5	$ 14.4
Derivative weighted average receive rate	2.35%	2.10%
Derivative weighted average pay rate	3.54%	4.44%
Weighted average maturity period	1 year 3 months 18 days	5 years 2 months 12 days
Designated As Hedging Instrument | Fair Value Hedging
Derivative Instruments
Derivative, notional amount	$ 5.3	$ 5.7
Derivative weighted average receive rate	1.39%	1.42%
Derivative weighted average pay rate	3.11%	3.11%
Weighted average maturity period	11 years 6 months	12 years 6 months

DERIVATIVE INSTRUMENTS, Cumulat

DERIVATIVE INSTRUMENTS, Cumulative Basis Adjustments for Fair Value Hedges (Details) - Loans. - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Cumulative Basis Adjustments for Fair Value Hedges
Carrying amount of the hedged assets	$ 5,400	$ 5,675
Cumulative amount of fair value hedging adjustment included in the carrying amount of the hedged assets	$ (293)	$ (498)

DERIVATIVE INSTRUMENTS, Fair Va

DERIVATIVE INSTRUMENTS, Fair Values of Derivative Instruments (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Fair Values of Derivative Instruments
Derivative assets	$ 379	$ 1,588
Derivative liabilities	3	1,074
Interest Rate Swap Agreements | Designated As Hedging Instrument | Other Assets.
Fair Values of Derivative Instruments
Derivative assets	293	498
Interest Rate Swap Agreements | Not Designated as Hedging Instrument | Other Assets.
Fair Values of Derivative Instruments
Derivative assets	3	1,074
Interest Rate Swap Agreements | Not Designated as Hedging Instrument | Accrued interest and other liabilities
Fair Values of Derivative Instruments
Derivative liabilities	3	1,074
Commitments to Originate Real Estate Loans for Sale | Not Designated as Hedging Instrument | Other Assets.
Fair Values of Derivative Instruments
Derivative assets	51	14
Forward Sales Commitments | Not Designated as Hedging Instrument | Other Assets.
Fair Values of Derivative Instruments
Derivative assets	$ 32	$ 2

VARIABLE INTEREST ENTITIES (Det

VARIABLE INTEREST ENTITIES (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Variable Interest Entity [Line Items]
Cash and cash equivalents	$ 1,875,064	$ 1,645,805
Premises and equipment, net	160,651	165,655
Other assets	313,854	281,903
Total assets	15,552,657	13,931,094	$ 11,410,295
Accrued interest and other liabilities	210,797	230,724
Total liabilities	$ 13,451,850	11,826,987
Variable Interest Entity, Primary Beneficiary [Member] | 706 North Clinton [Member]
Variable Interest Entity [Line Items]
Percentage of membership interest	50.00%
Cash and cash equivalents	$ 198	157
Premises and equipment, net	5,618	5,782
Other assets	57	48
Total assets	5,873	5,987
Accrued interest and other liabilities	0	$ 0
Minority interest	2,900
Loss of minority interest	4,200
Minority interest loss exposure related to financing agreement	$ 1,200

SEGMENT INFORMATION (Details)

SEGMENT INFORMATION (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Information about reportable segments [Abstract]
Net interest income	$ 374,412	$ 368,403	$ 359,175
Provision for credit losses	(8,839)	14,212	8,430
Noninterest revenue	246,235	228,419	230,619
Amortization of intangible assets	14,051	14,297	15,956
Acquisition expenses	701	4,933	8,608
Acquisition-related contingent consideration adjustment	200	0	0
Other operating expenses	373,186	357,304	347,462
Income before income taxes	241,348	206,076	209,338
Assets	15,552,657	13,931,094	11,410,295
Goodwill	799,109	793,708	773,810
Core deposit intangibles & Other intangibles	65,226	52,940	63,113
Eliminations [Member]
Information about reportable segments [Abstract]
Net interest income	0	0	0
Provision for credit losses	0	0	0
Noninterest revenue	(7,130)	(6,214)	(3,006)
Amortization of intangible assets	0	0	0
Acquisition expenses	0	0	0
Acquisition-related contingent consideration adjustment	0
Other operating expenses	(7,130)	(6,214)	(3,006)
Income before income taxes	0	0	0
Assets	(128,345)	(131,860)	(101,255)
Goodwill	0	0	0
Core deposit intangibles & Other intangibles	0	0	0
Banking [Member] | Operating Segments [Member]
Information about reportable segments [Abstract]
Net interest income	374,078	367,237	358,334
Provision for credit losses	(8,839)	14,212	8,430
Noninterest revenue	67,910	69,578	75,067
Amortization of intangible assets	4,744	5,515	5,751
Acquisition expenses	638	4,933	8,608
Acquisition-related contingent consideration adjustment	0
Other operating expenses	265,525	255,955	245,870
Income before income taxes	179,920	156,200	164,742
Assets	15,325,732	13,762,325	11,225,509
Goodwill	689,868	690,121	670,223
Core deposit intangibles & Other intangibles	9,087	13,831	16,418
Employee Benefit Services [Member] | Operating Segments [Member]
Information about reportable segments [Abstract]
Net interest income	293	943	665
Provision for credit losses	0	0	0
Noninterest revenue	116,621	103,456	99,483
Amortization of intangible assets	6,033	5,724	6,770
Acquisition expenses	36	0	0
Acquisition-related contingent consideration adjustment	200
Other operating expenses	64,423	60,709	59,428
Income before income taxes	46,222	37,966	33,950
Assets	257,879	217,780	209,690
Goodwill	85,321	83,275	83,275
Core deposit intangibles & Other intangibles	40,018	32,051	37,775
All Other [Member] | Operating Segments [Member]
Information about reportable segments [Abstract]
Net interest income	41	223	176
Provision for credit losses	0	0	0
Noninterest revenue	68,834	61,599	59,075
Amortization of intangible assets	3,274	3,058	3,435
Acquisition expenses	27	0	0
Acquisition-related contingent consideration adjustment	0
Other operating expenses	50,368	46,854	45,170
Income before income taxes	15,206	11,910	10,646
Assets	97,391	82,849	76,351
Goodwill	23,920	20,312	20,312
Core deposit intangibles & Other intangibles	$ 16,121	$ 7,058	$ 8,920