| Cover | Jun. 24, 2021 |
| Document Information [Line Items] | |
| Entity Registrant Name | DIME COMMUNITY BANCSHARES, INC. |
| Entity Central Index Key | 0000846617 |
| Entity Emerging Growth Company | false |
| Document Type | 8-K |
| Entity Central Index Key | 0000846617 |
| Amendment Flag | false |
| Document Period End Date | Sep. 30, 2021 |
| Entity File Number | 001-34096 |
| Entity Tax Identification Number | 11-2934195 |
| Entity Incorporation, State or Country Code | NY |
| Entity Address, Address Line One | 898 Veterans Memorial Highway, Suite 560 |
| Entity Address, City or Town | Hauppauge |
| Entity Address, State or Province | NY |
| Entity Address, Postal Zip Code | 11788 |
| City Area Code | 631 |
| Local Phone Number | 537-1000 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Common Stock | |
| Document Information [Line Items] | |
| Title of 12(b) Security | Common Stock, $0.01 Par Value |
| Trading Symbol | DCOM |
| Security Exchange Name | NASDAQ |
| Preferred Stock, Series A | |
| Document Information [Line Items] | |
| Title of 12(b) Security | Preferred Stock, Series A, $0.01 Par Value |
| Trading Symbol | DCOMP |
| Security Exchange Name | NASDAQ |
