DEPOSITS - Additional Information (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
DEPOSITS
Deposits in excess of the FDIC limit	$ 93.3	$ 115.3

The aggregate amount of domestic and foreign time deposit liabilities (including certificates of deposits, individual retirement accounts and open accounts) in denominations of $250,000 or more.

No definition available.

Name:	dcom_TimeDeposits250000OrMore
Namespace Prefix:	dcom_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant