RETIREMENT AND POSTRETIREMENT PLANS - Dime KSOP Plan - BMP and Outside Director Retirement Plan (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2021	Dec. 31, 2020
Defined Benefit Plan Disclosure [Line Items]
Curtailment loss		$ (1,543)
Postretirement Benefit Plan
Defined Benefit Plan Disclosure [Line Items]
Obligation			$ 13
Benefits paid		13
Dime KSOP Plan
Defined Benefit Plan Disclosure [Line Items]
Contribution plan cost		338
Dime KSOP Plan | Defined Benefit Plan, Equity Securities, Common Stock [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Plan Assets		40
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
Curtailment loss		(1,543)
Benefits paid		9,063
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