PARENT COMPANY FINANCIAL INFORMATION - Schedule of STATEMENTS OF CASH FLOWS (Details) - USD ($) $ in Thousands		12 Months Ended
	Jun. 10, 2025	Dec. 31, 2025	Dec. 31, 2024
Cash flows from operating activities:
Net Income		$ 15,104	$ 23,671
Adjustments to reconcile net income to net cash provided by operating activities:
Amortization of deferred costs on subordinated debt		56	0
Change in other assets		4,533	(2,167)
Change in other liabilities		4,143	2,119
Net change in fair value of equity investments		(211)	(179)
Net cash provided by operating activities		45,499	29,815
Cash flow from investing activities:
Net cash (used in) provided by investing activities		68,320	(57,723)
Cash flow from financing activities:
Cash dividends paid		(6,325)	(7,365)
Proceeds from subordinated debt issuance, net	$ 44,000	45,000	0
Payment of subordinated debt issuance costs		(1,028)	0
Purchase of treasury stock		(396)	(344)
Sale of treasury stock		536	430
Net cash (used in) provided by financing activities		(110,757)	38,096
Net increase (decrease) in cash and cash equivalents		3,062	10,188
Cash and cash equivalents at beginning of year		47,035
Cash and cash equivalents at end of year		50,097	47,035
Parent Company
Cash flows from operating activities:
Net Income		15,104	23,671
Adjustments to reconcile net income to net cash provided by operating activities:
Change in dividend receivable		0	1,469
Amortization of deferred costs on subordinated debt		56	0
Change in other assets		(816)	(127)
Change in other liabilities		(65)	235
Net change in fair value of equity investments		(9)	24
Net cash provided by operating activities		3,787	2,896
Cash flow from investing activities:
Downstream of subordinated debt		(37,000)	0
Net cash (used in) provided by investing activities		(37,000)	0
Cash flow from financing activities:
Cash dividends paid		(6,325)	(7,365)
Proceeds from subordinated debt issuance, net		45,000	0
Payment of subordinated debt issuance costs		(1,028)	0
Purchase of treasury stock		(396)	(344)
Sale of treasury stock		536	430
Net cash (used in) provided by financing activities		37,787	(7,279)
Net increase (decrease) in cash and cash equivalents		4,574	(4,383)
Cash and cash equivalents at beginning of year		2,252	6,635
Cash and cash equivalents at end of year		6,826	2,252
Parent Company | Chemung Canal Trust Company
Adjustments to reconcile net income to net cash provided by operating activities:
Equity in undistributed earnings		(10,381)	(22,344)
Parent Company | CFS Group Inc.
Adjustments to reconcile net income to net cash provided by operating activities:
Equity in undistributed earnings		$ (102)	$ (32)