RETIREMENT AND POSTRETIREMENT PLANS - Dime KSOP Plan - BMP and Outside Director Retirement Plan (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2022	Jun. 30, 2021
Dime KSOP Plan
Defined Benefit Plan Disclosure [Line Items]
Contribution plan cost	$ 0			$ 0
BMP and Outside Director Retirement Plan
Defined Benefit Plan Disclosure [Line Items]
Termination Age of Board Members			75 years
Curtailment loss		$ 1,500,000
Outside Director Retirement Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Obligation		2,800,000
Board Member Retirement Plan
Defined Benefit Plan Disclosure [Line Items]
Obligation		$ 6,200,000