TREASURY STOCK (Details) (USD $)	Apr. 30, 2014	Apr. 30, 2013
TREASURY STOCK [Abstract]
Treasury stock issued attributable to restricted stock award grant (in shares)	121,333	145,925
Closing price of company stock (in dollars per share)	$ 16.30	$ 14.27
Issuance of Treasury Stock for BMP award	9,364	15,049

Number of treasury shares (units) issued during the period used to satisfy a grant of restricted stock awards.

No definition available.

Name:	dcom_TreasuryStockIssuedAttributableToShareBasedPaymentArrangements
Namespace Prefix:	dcom_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant