Document and Entity Information - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Feb. 22, 2022	Jun. 30, 2021
Entity Listings [Line Items]
Document Type	10-K
Document Annual Report	true
Document Transition Report	false
Document Period End Date	Dec. 31, 2021
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 Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	true
Entity Shell Company	false
Entity Public Float			$ 1,150
Entity Common Stock, Shares Outstanding		39,647,623
Auditor Name	Crowe LLP
Auditor Firm ID	173
Auditor Location	New York, New York
Entity Central Index Key	0000846617
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	FY
Amendment Flag	false
Common Stock
Entity Listings [Line Items]
Title of 12(b) Security	Common Stock, par value $0.01 per share
Trading Symbol	DCOM
Security Exchange Name	NASDAQ
Preferred Stock, Series A
Entity Listings [Line Items]
Title of 12(b) Security	Preferred Stock, Series A, par value $0.01 per share
Trading Symbol	DCOMP
Security Exchange Name	NASDAQ