RETIREMENT AND POSTRETIREMENT PLANS - Dime KSOP Plan - BMP and Outside Director Retirement Plan (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2021	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Defined Benefit Plan Disclosure [Line Items]
Curtailment loss			$ (1,543)	$ 1,651
POSTRETIREMENT PLANS
Defined Benefit Plan Disclosure [Line Items]
Obligation				13	$ 1,608
Curtailment loss				(1,651)
Benefits paid			13	165
Dime KSOP Plan
Defined Benefit Plan Disclosure [Line Items]
Contribution plan cost		$ 300	1,900	1,900
Dime KSOP Plan | Defined Benefit Plan, Equity Securities, Common Stock [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Plan Assets		$ 40	33,700
BMP and Outside Director Retirement Plan
Defined Benefit Plan Disclosure [Line Items]
Termination Age of Board Members		75 years
Curtailment loss	$ 1,500
BMP and Outside Director Retirement Plan | RETIREMENT PLANS
Defined Benefit Plan Disclosure [Line Items]
Obligation				9,328	$ 9,360
Curtailment loss			(1,543)
Benefits paid			$ 9,063	771
Outside Director Retirement Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Obligation		$ 2,800
Board Member Retirement Plan
Defined Benefit Plan Disclosure [Line Items]
Obligation		$ 6,200
Board Member Retirement Plan | Defined Benefit Plan, Equity Securities, Common Stock [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Plan Assets				$ 2,200