XML 108 R92.htm IDEA: XBRL DOCUMENT
v3.20.4

DERIVATIVES - Narrative (Details) $ in Thousands | 12 Months Ended
--- | ---
Dec. 31, 2020 USD ($) contract | Dec. 31, 2019 USD ($) | Dec. 31, 2018 USD ($)
Derivative [Line Items] |  |  |
Notional amounts | $ 1,100,000 | $ 823,900 |
Derivative liability position net | 0 |  |
Derivative asset position net | 57,100 |  |
Collateral received against obligations in net asset position | 57,900 |  |
Collateral posted in net liability position | 0 |  |
Derivative designated as a cash flow hedge | Amount Reclassified from Accumulated Other Comprehensiven (loss) Income |  |  |
Derivative [Line Items] |  |  |
Accelerated reclassification, loss from other comprehensive income to earnings as a result of the hedged forecasted transactions becoming probable not to occur | 3,400 |  |
Interest rate swaps | Derivative designated as a cash flow hedge |  |  |
Derivative [Line Items] |  |  |
Notional amounts | 280,000 | 290,000 |
Notional amount terminated | $ 125,000 |  |
Derivative, number of terminations | contract | 4 |  |
Loss on termination of swaps, reported in non-interest income | $ 3,400 |  |
Interest income (expense) on derivative | 1,700 | $ 1,600 | $ 1,100
Interest rate swaps | Derivative designated as a cash flow hedge | Federal Home Loan Bank of New York |  |  |
Derivative [Line Items] |  |  |
Reclassified as an increase to interest expense during the next twelve months | 2,100 |  |
Interest rate swaps | Derivative designated as a cash flow hedge | Federal Home Loan Bank of New York | Amount Reclassified from Accumulated Other Comprehensiven (loss) Income |  |  |
Derivative [Line Items] |  |  |
Increase to interest expense | $ 1,700 |  |

X
- Definition Nominal or face amount of terminated derivative. + References No definition available. + Details
Name: | dcom_DerivativeAssetTerminatedNotionalAmount
Namespace Prefix: | dcom_
Data Type: | xbrli:monetaryItemType
Balance Type: | na
Period Type: | instant

X
- Definition Represents amount of fair value amounts of derivative instruments in a net asset position at the end of the reporting period. + References No definition available. + Details
Name: | dcom_DerivativeNetAssetPositionAggregateFairValue
Namespace Prefix: | dcom_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Represents the amount of interest income (expense) recorded on interest rate derivative. + References No definition available. + Details
Name: | dcom_InterestExpenseOnInterestRateDerivative
Namespace Prefix: | dcom_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Represents amount of reclassifications to interest expense. + References No definition available. + Details
Name: | dcom_ReclassificationsToInterestExpense
Namespace Prefix: | dcom_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The estimated net amount of existing gains or losses on cash flow hedges at the reporting date expected to be reclassified to earnings within the next 12 months. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 30 -Section 50 -Paragraph 1 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=121549185&loc=d3e80748-113994 + Details
Name: | us-gaap_CashFlowHedgeGainLossToBeReclassifiedWithinTwelveMonths
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Nominal or face amount used to calculate payments on the derivative asset. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 1A -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=121590274&loc=SL5579245-113959 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 1B -URI http://asc.fasb.org/extlink&oid=121590274&loc=SL5580258-113959 Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 1A -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=121590274&loc=SL5579245-113959 + Details
Name: | us-gaap_DerivativeAssetNotionalAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | na
Period Type: | instant

X
- Definition Amount of obligation to return cash collateral under master netting arrangements that have not been offset against derivative assets. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 20 -Section 55 -Paragraph 13 -URI http://asc.fasb.org/extlink&oid=99393222&loc=SL20226016-175313 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 8 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=121590274&loc=d3e41678-113959 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 20 -Section 50 -Paragraph 3 -Subparagraph (d)(2) -URI http://asc.fasb.org/extlink&oid=51824906&loc=SL20225862-175312 + Details
Name: | us-gaap_DerivativeCollateralObligationToReturnCash
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of right to receive cash collateral under master netting arrangements that have not been offset against derivative liabilities. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 20 -Section 55 -Paragraph 13 -URI http://asc.fasb.org/extlink&oid=99393222&loc=SL20226016-175313 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 8 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=121590274&loc=d3e41678-113959 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 20 -Section 50 -Paragraph 3 -Subparagraph (d)(2) -URI http://asc.fasb.org/extlink&oid=51824906&loc=SL20225862-175312 + Details
Name: | us-gaap_DerivativeCollateralRightToReclaimCash
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_DerivativeLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The aggregate fair value amounts of derivative instruments that contain credit-risk-related contingent features that are in a net liability position at the end of the reporting period. For nonderivative instruments that are designated and qualify as hedging instruments, the fair value amounts are the carrying value of the nonderivative hedging instrument, including the adjustment for the foreign currency transaction gain (loss) on that instrument. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4H -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=121590274&loc=SL5624258-113959 + Details
Name: | us-gaap_DerivativeNetLiabilityPositionAggregateFairValue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition The number of derivative instruments of a particular group held by the entity. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 1A -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=121590274&loc=SL5579245-113959 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 1B -URI http://asc.fasb.org/extlink&oid=121590274&loc=SL5580258-113959 + Details
Name: | us-gaap_DerivativeNumberOfInstrumentsHeld
Namespace Prefix: | us-gaap_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Aggregate loss on all derivative instruments charged against earnings during the period, before tax effects. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4A -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=121590274&loc=SL5618551-113959 + Details
Name: | us-gaap_LossOnDerivativeInstrumentsPretax
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The amount of loss reclassified into earnings in the period when cash flow hedge is discontinued because it is probable that the original forecasted transactions will not occur by the end of the original period or an additional two month time period. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 30 -Section 50 -Paragraph 1 -Subparagraph (e) -URI http://asc.fasb.org/extlink&oid=121549185&loc=d3e80748-113994 + Details
Name: | us-gaap_LossOnDiscontinuationOfCashFlowHedgeDueToForecastedTransactionProbableOfNotOccurring
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Details
Name: | us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis=us-gaap_CashFlowHedgingMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeAxis=us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=us-gaap_InterestRateSwapMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_FederalHomeLoanBankAdvancesBranchOfFHLBBankAxis=srt_FederalHomeLoanBankOfNewYorkMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |