Annual report pursuant to Section 13 and 15(d)

Debt (Details 3)

v2.4.1.9
Debt (Details 3) (USD $)
In Thousands, unless otherwise specified
Dec. 31, 2014
Dec. 31, 2013
Carrying amount and estimated fair value of debt    
Debt, net $ 1,920,057us-gaap_LongTermDebt $ 1,927,703us-gaap_LongTermDebt
Senior Notes    
Carrying amount and estimated fair value of debt    
Debt, net 890,900us-gaap_LongTermDebt
/ us-gaap_DebtInstrumentAxis
= us-gaap_SeniorNotesMember
 
4.25% Exchangeable Senior Notes    
Carrying amount and estimated fair value of debt    
Debt, net 572us-gaap_LongTermDebt
/ us-gaap_DebtInstrumentAxis
= ofc_Exchangeable425PercentSeniorNotesMember
563us-gaap_LongTermDebt
/ us-gaap_DebtInstrumentAxis
= ofc_Exchangeable425PercentSeniorNotesMember
Carrying Amount    
Carrying amount and estimated fair value of debt    
Variable-rate debt 639,877us-gaap_LongtermDebtPercentageBearingVariableInterestAmount
/ us-gaap_FairValueByMeasurementBasisAxis
= us-gaap_CarryingReportedAmountFairValueDisclosureMember
657,691us-gaap_LongtermDebtPercentageBearingVariableInterestAmount
/ us-gaap_FairValueByMeasurementBasisAxis
= us-gaap_CarryingReportedAmountFairValueDisclosureMember
Debt, net 1,920,057us-gaap_LongTermDebt
/ us-gaap_FairValueByMeasurementBasisAxis
= us-gaap_CarryingReportedAmountFairValueDisclosureMember
1,927,703us-gaap_LongTermDebt
/ us-gaap_FairValueByMeasurementBasisAxis
= us-gaap_CarryingReportedAmountFairValueDisclosureMember
Carrying Amount | Senior Notes    
Carrying amount and estimated fair value of debt    
Fixed-rate debt 890,862us-gaap_LongtermDebtPercentageBearingFixedInterestAmount
/ us-gaap_DebtInstrumentAxis
= us-gaap_SeniorNotesMember
/ us-gaap_FairValueByMeasurementBasisAxis
= us-gaap_CarryingReportedAmountFairValueDisclosureMember
592,689us-gaap_LongtermDebtPercentageBearingFixedInterestAmount
/ us-gaap_DebtInstrumentAxis
= us-gaap_SeniorNotesMember
/ us-gaap_FairValueByMeasurementBasisAxis
= us-gaap_CarryingReportedAmountFairValueDisclosureMember
Carrying Amount | 4.25% Exchangeable Senior Notes    
Carrying amount and estimated fair value of debt    
Fixed-rate debt 572us-gaap_LongtermDebtPercentageBearingFixedInterestAmount
/ us-gaap_DebtInstrumentAxis
= ofc_Exchangeable425PercentSeniorNotesMember
/ us-gaap_FairValueByMeasurementBasisAxis
= us-gaap_CarryingReportedAmountFairValueDisclosureMember
563us-gaap_LongtermDebtPercentageBearingFixedInterestAmount
/ us-gaap_DebtInstrumentAxis
= ofc_Exchangeable425PercentSeniorNotesMember
/ us-gaap_FairValueByMeasurementBasisAxis
= us-gaap_CarryingReportedAmountFairValueDisclosureMember
Carrying Amount | Fixed-rate debt excluding other fixed rate debt not separately disclosed    
Carrying amount and estimated fair value of debt    
Fixed-rate debt 388,746us-gaap_LongtermDebtPercentageBearingFixedInterestAmount
/ us-gaap_DebtInstrumentAxis
= ofc_OtherFixedRateDebtMember
/ us-gaap_FairValueByMeasurementBasisAxis
= us-gaap_CarryingReportedAmountFairValueDisclosureMember
676,760us-gaap_LongtermDebtPercentageBearingFixedInterestAmount
/ us-gaap_DebtInstrumentAxis
= ofc_OtherFixedRateDebtMember
/ us-gaap_FairValueByMeasurementBasisAxis
= us-gaap_CarryingReportedAmountFairValueDisclosureMember
Total Estimated Fair Value    
Carrying amount and estimated fair value of debt    
Variable-rate debt 642,091us-gaap_LongtermDebtPercentageBearingVariableInterestAmount
/ us-gaap_FairValueByMeasurementBasisAxis
= us-gaap_EstimateOfFairValueFairValueDisclosureMember
657,527us-gaap_LongtermDebtPercentageBearingVariableInterestAmount
/ us-gaap_FairValueByMeasurementBasisAxis
= us-gaap_EstimateOfFairValueFairValueDisclosureMember
Debt, net 1,900,067us-gaap_LongTermDebt
/ us-gaap_FairValueByMeasurementBasisAxis
= us-gaap_EstimateOfFairValueFairValueDisclosureMember
1,884,473us-gaap_LongTermDebt
/ us-gaap_FairValueByMeasurementBasisAxis
= us-gaap_EstimateOfFairValueFairValueDisclosureMember
Total Estimated Fair Value | Senior Notes    
Carrying amount and estimated fair value of debt    
Fixed-rate debt 901,599us-gaap_LongtermDebtPercentageBearingFixedInterestAmount
/ us-gaap_DebtInstrumentAxis
= us-gaap_SeniorNotesMember
/ us-gaap_FairValueByMeasurementBasisAxis
= us-gaap_EstimateOfFairValueFairValueDisclosureMember
575,374us-gaap_LongtermDebtPercentageBearingFixedInterestAmount
/ us-gaap_DebtInstrumentAxis
= us-gaap_SeniorNotesMember
/ us-gaap_FairValueByMeasurementBasisAxis
= us-gaap_EstimateOfFairValueFairValueDisclosureMember
Total Estimated Fair Value | 4.25% Exchangeable Senior Notes    
Carrying amount and estimated fair value of debt    
Fixed-rate debt 575us-gaap_LongtermDebtPercentageBearingFixedInterestAmount
/ us-gaap_DebtInstrumentAxis
= ofc_Exchangeable425PercentSeniorNotesMember
/ us-gaap_FairValueByMeasurementBasisAxis
= us-gaap_EstimateOfFairValueFairValueDisclosureMember
575us-gaap_LongtermDebtPercentageBearingFixedInterestAmount
/ us-gaap_DebtInstrumentAxis
= ofc_Exchangeable425PercentSeniorNotesMember
/ us-gaap_FairValueByMeasurementBasisAxis
= us-gaap_EstimateOfFairValueFairValueDisclosureMember
Total Estimated Fair Value | Fixed-rate debt excluding other fixed rate debt not separately disclosed    
Carrying amount and estimated fair value of debt    
Fixed-rate debt $ 355,802us-gaap_LongtermDebtPercentageBearingFixedInterestAmount
/ us-gaap_DebtInstrumentAxis
= ofc_OtherFixedRateDebtMember
/ us-gaap_FairValueByMeasurementBasisAxis
= us-gaap_EstimateOfFairValueFairValueDisclosureMember
$ 650,997us-gaap_LongtermDebtPercentageBearingFixedInterestAmount
/ us-gaap_DebtInstrumentAxis
= ofc_OtherFixedRateDebtMember
/ us-gaap_FairValueByMeasurementBasisAxis
= us-gaap_EstimateOfFairValueFairValueDisclosureMember