Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2020	Feb. 28, 2021	Jun. 30, 2020
Document Information [Line Items]
Document Type	10-K
Document Annual Report	true
Document Transition Report	false
Document Period End Date	Dec. 31, 2020
Entity File Number	001-34096
Entity Registrant Name	DIME COMMUNITY BANCSHARES, INC.
Entity Incorporation, State or Country Code	NY
Entity Tax Identification Number	11-2934195
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
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	true
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		41,488,275
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	FY
Entity Central Index Key	0000846617
Amendment Flag	false
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Public Float			$ 377,838,854
Common Stock
Document Information [Line Items]
Title of 12(b) Security	Common Stock
Trading Symbol	DCOM
Security Exchange Name	NASDAQ
Preferred Stock
Document Information [Line Items]
Title of 12(b) Security	Preferred Stock
Trading Symbol	DCOMP
Security Exchange Name	NASDAQ