RETIREMENT AND POSTRETIREMENT PLANS - Dime KSOP Plan - BMP and Outside Director Retirement Plan (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
BMP and Outside Director Retirement Plan
Defined Benefit Plan Disclosure [Line Items]
Termination Age of Board Members	75 years
Curtailment loss		$ 1.5
Outside Director Retirement Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Obligation	$ 2.8
Board Member Retirement Plan
Defined Benefit Plan Disclosure [Line Items]
Obligation	$ 6.2