Number of financing receivables that have been commitments to borrowers with outstanding troubled debt restructurings.

No definition available.

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- Definition

Number of loans modified in a manner that met the criteria of a TDR.

+ References

No definition available.

+ Details

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Period Type:	duration

- Definition

The number of TDR loans that have defaulted within twelve months following modification.

+ References

No definition available.

+ Details

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- References

No definition available.

+ Details

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Namespace Prefix:	dcom_
Data Type:	xbrli:stringItemType
Balance Type:	na
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- Definition

Number of financing receivables that have been modified by troubled debt restructurings.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 33
-URI http://asc.fasb.org/extlink&oid=66008989&loc=SL6953676-111524

+ Details

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- Definition

The amount of the outstanding recorded investment related to financing receivables that have been modified by troubled debt restructurings.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 40
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=25495931&loc=d3e18845-111554

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Recorded Investment
-URI http://asc.fasb.org/extlink&oid=65880944

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Details

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Namespace Prefix:
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- Details

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- Details

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- Details

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LOANS RECEIVABLE AND CREDIT QUALITY, Troubled Debt Restructurings (Details) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2016 USD ($) Loan	Sep. 30, 2015 Loan	Sep. 30, 2016 USD ($) Loan	Sep. 30, 2015 Loan	Dec. 31, 2015 USD ($) Loan
Troubled Debt Restructuring on Receivables [Abstract]
Number of loans modified	0	0		0
Number of loan committed to borrowers	0		0		0
TDRs which defaulted within twelve months following the modification	0	0	0	0
One- to Four-Family Residential, Including Condominium and Cooperative Apartment [Member]
Troubled Debt Restructuring on Receivables [Abstract]
Number of loans modified			1
Real Estate Loans [Member]
Troubled Debt Restructuring on Receivables [Abstract]
Number of loans			7		8
Balance \| $	$ 8,739		$ 8,739		$ 9,273
Real Estate Loans [Member] \| One- to Four-Family Residential, Including Condominium and Cooperative Apartment [Member] \| Accruing TDRs [Member]
Troubled Debt Restructuring on Receivables [Abstract]
Number of loans			2		2
Balance \| $	410		$ 410		$ 598
Real Estate Loans [Member] \| Multifamily Residential and Residential Mixed Use [Member] \| Accruing TDRs [Member]
Troubled Debt Restructuring on Receivables [Abstract]
Number of loans			3		3
Balance \| $	667		$ 667		$ 696
Real Estate Loans [Member] \| Commercial Mixed Use Real Estate [Member] \| Accruing TDRs [Member]
Troubled Debt Restructuring on Receivables [Abstract]
Number of loans			1		1
Balance \| $	4,282		$ 4,282		$ 4,344
Real Estate Loans [Member] \| Commercial Real Estate [Member] \| Accruing TDRs [Member]
Troubled Debt Restructuring on Receivables [Abstract]
Number of loans			1		1
Balance \| $	3,380		$ 3,380		$ 3,428
Real Estate Loans [Member] \| Commercial Real Estate [Member] \| Non-accruing TDRs [Member]
Troubled Debt Restructuring on Receivables [Abstract]
Number of loans			0		1
Balance \| $	$ 0		$ 0		$ 207