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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 |

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- Definition Amount of payment to participant of defined benefit plan which decreases benefit obligation. For pension plan, payment includes, but is not limited to, pension benefits and death benefits. For other postretirement plan, payment includes, but is not limited to, prescription drug benefits, health care benefits, life insurance benefits, and legal, educational and advisory services. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 60 -Name Accounting Standards Codification -Section 50 -Paragraph 4 -Publisher FASB -URI https://asc.fasb.org//1943274/2147480266/715-60-50-4 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (a)(6) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480506/715-20-50-1 + Details
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