| Document and Entity Information | Jan. 08, 2021 |
| Entity Listings [Line Items] | |
| Document Type | 8-K |
| Amendment Flag | false |
| Document Period End Date | Jan. 8, 2021 |
| Entity Registrant Name | DIME COMMUNITY BANCSHARES, INC. |
| Entity Incorporation, State or Country Code | DE |
| Entity File Number | 000-27782 |
| Entity Tax Identification Number | 11-3297463 |
| Entity Address, Address Line One | 300 Cadman Plaza West, 8th Floor |
| Entity Address, City or Town | Brooklyn |
| Entity Address, State or Province | NY |
| Entity Address, Postal Zip Code | 11201 |
| City Area Code | 718 |
| Local Phone Number | 782-6200 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Entity Emerging Growth Company | false |
| Entity Central Index Key | 0001005409 |
| Common Stock [Member] | |
| Entity Listings [Line Items] | |
| Title of 12(b) Security | Common Stock, $0.01 Par Value |
| Trading Symbol | DCOM |
| Security Exchange Name | NASDAQ |
| Series A Preferred Stock [Member] | |
| Entity Listings [Line Items] | |
| Title of 12(b) Security | Preferred Stock, Series A, $0.01 Par Value |
| Trading Symbol | DCOMP |
| Security Exchange Name | NASDAQ |
