RETIREMENT AND POSTRETIREMENT PLANS - Dime KSOP Plan - BMP and Outside Director Retirement Plan (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Mar. 31, 2021	Sep. 30, 2022	Sep. 30, 2021
Defined Benefit Plan Disclosure [Line Items]
Curtailment loss			$ (1,543)
Dime KSOP Plan
Defined Benefit Plan Disclosure [Line Items]
Contribution plan cost	$ 338
BMP and Outside Director Retirement Plan
Defined Benefit Plan Disclosure [Line Items]
Termination Age of Board Members		75 years
Curtailment loss	1,500
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