XML 99 R75.htm IDEA: XBRL DOCUMENT
v3.3.1.900

Debt (Details 4) |  |  |  |  |  |  |  |  |  | 1 Months Ended | 12 Months Ended
--- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | ---
Dec. 17, 2015 USD ($) | Aug. 28, 2015 USD ($) | Jun. 29, 2015 USD ($) | May. 06, 2015 USD ($) extensions | May. 14, 2014 USD ($) | Dec. 23, 2013 USD ($) | Aug. 03, 2012 USD ($) | Feb. 14, 2012 USD ($) | Sep. 01, 2011 USD ($) | Dec. 31, 2014 USD ($) | Dec. 31, 2015 USD ($) | Dec. 31, 2014 USD ($) | Dec. 31, 2013 USD ($)
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Gain (loss) on early extinguishment of debt |  |  |  |  |  |  |  |  |  |  | $ 85,275,000 | $ (9,552,000) | $ (27,030,000)
Term Credit Facility Effective February 2012 [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Initial amount borrowed |  |  |  |  |  |  |  | $ 250,000,000 |  |  |  |  |
Term Credit Facility Effective August 2012 [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Initial amount borrowed |  |  |  |  |  |  | $ 120,000,000 |  |  |  |  |  |
Additional borrowing capacity available provided there is no default under the agreement |  |  |  |  |  |  | $ 80,000,000 |  |  |  |  |  |
Term Credit Facility Effective September 2011 [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Initial amount borrowed |  |  |  |  |  |  |  |  | $ 400,000,000 |  |  |  |
Repayments of debt |  |  |  |  |  |  |  |  |  |  |  | 100,000,000 | $ 150,000,000
4.25% Exchangeable Senior Notes [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Stated interest rate (as a percent) |  |  |  |  |  |  |  |  |  |  |  |  | 4.25%
Unamortized discount included in carrying value |  |  |  |  |  |  |  |  |  | $ 3,000 |  | $ 3,000 |
Gain (loss) on early extinguishment of debt |  |  |  |  |  |  |  |  |  |  |  |  | $ (25,900,000)
Amount of loans repaid upon entry into Revolving Credit Facility and Term Loan Agreement |  |  |  |  |  |  |  |  |  |  |  |  | $ 239,400,000
Fixed rate mortgage loans [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Debt settled through the surrender of real estate assets |  | $ 150,000,000 |  |  |  |  |  |  |  |  |  |  |
Minimum [Member] | Revolving Credit Facility [Member] | London Interbank Offered Rate (LIBOR) [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Variable rate, spread (as a percent) |  |  |  |  |  |  |  |  |  |  | 0.875% |  |
Minimum [Member] | Term Credit Facility Effective February 2012 [Member] | London Interbank Offered Rate (LIBOR) [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Variable rate, spread (as a percent) |  |  |  | 0.90% |  |  |  |  |  |  |  |  |
Minimum [Member] | Term Credit Facility Effective August 2012 [Member] | London Interbank Offered Rate (LIBOR) [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Variable rate, spread (as a percent) |  |  |  |  |  |  | 2.10% |  |  |  |  |  |
Maximum [Member] | Revolving Credit Facility [Member] | London Interbank Offered Rate (LIBOR) [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Variable rate, spread (as a percent) |  |  |  |  |  |  |  |  |  |  | 1.60% |  |
Maximum [Member] | Term Credit Facility Effective February 2012 [Member] | London Interbank Offered Rate (LIBOR) [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Variable rate, spread (as a percent) |  |  |  | 1.85% |  |  |  |  |  |  |  |  |
Maximum [Member] | Term Credit Facility Effective August 2012 [Member] | London Interbank Offered Rate (LIBOR) [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Variable rate, spread (as a percent) |  |  |  |  |  |  | 2.60% |  |  |  |  |  |
Secured Loans Due November 2015 And January 2016 [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Gain (loss) on early extinguishment of debt |  |  |  |  |  |  |  |  |  | $ (9,100,000) |  |  |
Secured Loan Due November 2015 [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Stated interest rate (as a percent) |  |  |  |  |  |  |  |  |  | 5.53% |  | 5.53% |
Amount of loans repaid upon entry into Revolving Credit Facility and Term Loan Agreement |  |  |  |  |  |  |  |  |  | $ 103,000,000 |  |  |
Secured Loan Due January 2016 [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Stated interest rate (as a percent) |  |  |  |  |  |  |  |  |  | 5.56% |  | 5.56% |
Amount of loans repaid upon entry into Revolving Credit Facility and Term Loan Agreement |  |  |  |  |  |  |  |  |  | $ 108,500,000 |  |  |
Revolving Credit Facility [Member] | Revolving Credit Facility [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Maximum availability |  |  |  |  |  |  |  |  |  |  | $ 800,000,000 |  |
Expansion right, maximum borrowing capacity |  |  |  |  |  |  |  |  |  |  | $ 1,300,000,000 |  |
Amount available as a percentage of unencumbered Asset value |  |  |  |  |  |  |  |  |  |  | 60.00% |  |
Line of credit facility, extension fee percentage |  |  |  |  |  |  |  |  |  |  | 0.075% |  |
Remaining borrowing capacity |  |  |  |  |  |  |  |  |  |  | $ 741,700,000 |  |
Weighted average borrowings |  |  |  |  |  |  |  |  |  |  | $ 125,000,000 | $ 15,900,000 |
Weighted average interest rate (as a percent) |  |  |  |  |  |  |  |  |  | 1.47% | 1.40% | 1.47% |
Line of Credit [Member] | Revolving Credit Facility [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Number of extensions | extensions |  |  |  | 2 |  |  |  |  |  |  |  |  |
Extension option period (in years) |  |  |  | 6 months |  |  |  |  |  |  |  |  |
Line of Credit [Member] | Revolving Credit Facility [Member] | Minimum [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Commitment fee percentage |  |  |  | 0.125% |  |  |  |  |  |  |  |  |
Line of Credit [Member] | Revolving Credit Facility [Member] | Minimum [Member] | London Interbank Offered Rate (LIBOR) [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Variable rate, spread (as a percent) |  |  |  | 0.875% |  |  |  |  |  |  |  |  |
Line of Credit [Member] | Revolving Credit Facility [Member] | Maximum [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Commitment fee percentage |  |  |  | 0.30% |  |  |  |  |  |  |  |  |
Line of Credit [Member] | Revolving Credit Facility [Member] | Maximum [Member] | London Interbank Offered Rate (LIBOR) [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Variable rate, spread (as a percent) |  |  |  | 1.60% |  |  |  |  |  |  |  |  |
Line of Credit [Member] | Term Loan Facilities [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Maximum availability |  |  |  | $ 300,000,000 |  |  |  |  |  |  |  |  |
Increase to maximum borrowing capacity |  |  |  | 200,000,000 |  |  |  |  |  |  |  |  |
Aggregate maximum borrowing capacity |  |  |  | $ 500,000,000 |  |  |  |  |  |  |  |  |
Unsecured Debt [Member] | Term Credit Facility Effective December 2015 [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Maximum availability | $ 250,000,000 |  |  |  |  |  |  |  |  |  |  |  |
Initial amount borrowed | 100,000,000 |  |  |  |  |  |  |  |  |  |  |  |
Increase to maximum borrowing capacity | $ 150,000,000 |  |  |  |  |  |  |  |  |  |  |  |
Unsecured Debt [Member] | Minimum [Member] | Term Credit Facility Effective December 2015 [Member] | London Interbank Offered Rate (LIBOR) [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Variable rate, spread (as a percent) | 1.40% |  |  |  |  |  |  |  |  |  |  |  |
Unsecured Debt [Member] | Maximum [Member] | Term Credit Facility Effective December 2015 [Member] | London Interbank Offered Rate (LIBOR) [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Variable rate, spread (as a percent) | 2.35% |  |  |  |  |  |  |  |  |  |  |  |
Senior Notes [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Redemption price (percent) |  |  |  |  |  |  |  |  |  |  | 100.00% |  |
Senior Notes [Member] | 3.70% Senior Notes [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Initial amount borrowed |  |  |  |  | $ 297,300,000 |  |  |  |  |  |  |  |
Loan amount |  |  |  |  |  |  |  |  |  |  | $ 300,000,000 |  |
Stated interest rate (as a percent) |  |  |  |  | 3.70% |  |  |  |  |  | 3.70% |  |
Debt issuance as a percentage of principal amount |  |  |  |  | 99.739% |  |  |  |  |  |  |  |
Unamortized discount included in carrying value |  |  |  |  |  |  |  |  |  | $ 2,400,000 | $ 2,100,000 | $ 2,400,000 |
Interest rate on debt (as a percent) |  |  |  |  |  |  |  |  |  |  | 3.85% |  |
Senior Notes [Member] | 3.70% Senior Notes [Member] | Adjusted Treasury [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Basis points used in determining redemption price prior to maturity |  |  |  |  |  |  |  |  |  |  | 250.00% |  |
Senior Notes [Member] | 5.0% Senior Notes [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Loan amount |  |  | $ 300,000,000 |  |  |  |  |  |  |  |  |  |
Stated interest rate (as a percent) |  |  | 5.00% |  |  |  |  |  |  |  | 5.00% |  |
Debt issuance as a percentage of principal amount |  |  | 99.51% |  |  |  |  |  |  |  |  |  |
Unamortized discount included in carrying value |  |  |  |  |  |  |  |  |  |  | $ 3,300,000 |  |
Interest rate on debt (as a percent) |  |  |  |  |  |  |  |  |  |  | 5.15% |  |
Proceeds from debt, net |  |  | $ 296,600,000 |  |  |  |  |  |  |  |  |  |
Senior Notes [Member] | 5.0% Senior Notes [Member] | Adjusted Treasury [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Basis points used in determining redemption price prior to maturity |  |  |  |  |  |  |  |  |  |  | 450.00% |  |
Senior Notes [Member] | 3.60% Senior Notes [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Stated interest rate (as a percent) |  |  |  |  |  |  |  |  |  |  | 3.60% |  |
Unamortized discount included in carrying value |  |  |  |  |  |  |  |  |  | 2,500,000 | $ 2,200,000 | 2,500,000 |
Interest rate on debt (as a percent) |  |  |  |  |  |  |  |  |  |  | 3.70% |  |
Senior Notes [Member] | 3.60% Senior Notes [Member] | Adjusted Treasury [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Basis points used in determining redemption price prior to maturity |  |  |  |  |  |  |  |  |  |  | 300.00% |  |
Senior Notes [Member] | 5.250% Senior Notes [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Stated interest rate (as a percent) |  |  |  |  |  |  |  |  |  |  | 5.25% |  |
Unamortized discount included in carrying value |  |  |  |  |  |  |  |  |  | $ 4,200,000 | $ 3,800,000 | $ 4,200,000 |
Interest rate on debt (as a percent) |  |  |  |  |  |  |  |  |  |  | 5.49% |  |
Senior Notes [Member] | 5.250% Senior Notes [Member] | Adjusted Treasury [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Basis points used in determining redemption price prior to maturity |  |  |  |  |  |  |  |  |  |  | 400.00% |  |
Senior Notes [Member] | 4.25% Exchangeable Senior Notes [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Stated interest rate (as a percent) |  |  |  |  |  |  |  |  |  | 4.25% |  | 4.25% |
Operating properties, net [Member] | December 2013 Portfolio Conveyance [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Gain (loss) on early extinguishment of debt |  |  |  |  |  | $ 67,800,000 |  |  |  |  |  |  |
Debt settled through the surrender of real estate assets |  |  |  |  |  | $ 146,500,000 |  |  |  |  |  |  |
Operating properties, net [Member] | 15000 and 15010 Conference Center Drive [Member] | Northern Virginia [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Gain (loss) on early extinguishment of debt |  | 84,800,000 |  |  |  |  |  |  |  |  |  |  |
Debt settled through the surrender of real estate assets |  | $ 150,000,000 |  |  |  |  |  |  |  |  |  |  |

X
- Definition Basis points added to adjusted treasury note used in determining the redemption price of the debt instrument prior to maturity. + References No definition available. + Details
Name: | ofc_Basispointsusedindeterminingredemptionpricepriortomaturity
Namespace Prefix: | ofc_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Represents the carrying value of debt settled through the surrender of real estate assets. + References No definition available. + Details
Name: | ofc_CarryingValueOfDebtSettledThroughSurrenderOfRealEstateAssets
Namespace Prefix: | ofc_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Additional borrowing capacity available under the debt agreement provided that there is no default under the agreement and subject to the approval of the lender. + References No definition available. + Details
Name: | ofc_CreditFacilityAdditionalBorrowingCapacityAvailable
Namespace Prefix: | ofc_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Represents the period over which the debt may be extended at the option of the entity, subject to certain conditions. + References No definition available. + Details
Name: | ofc_DebtInstrumentExtensionOptionTerm
Namespace Prefix: | ofc_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Represents the debt instrument issuance price, expressed as a percentage of the principal amount of the debt instrument. + References No definition available. + Details
Name: | ofc_Debtissuanceasapercentageofprincipalamount
Namespace Prefix: | ofc_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Maximum borrowing availability to which the credit facility may be expanded as per the terms of the agreement, which is the right of the reporting entity. + References No definition available. + Details
Name: | ofc_LineOfCreditExpansionRightMaximumBorrowingAvailabiliity
Namespace Prefix: | ofc_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Percentage of unencumbered asset value used for computation of amounts available under the facility. + References No definition available. + Details
Name: | ofc_LineOfCreditFacilityPercentageOfUnencumberedAssetValue
Namespace Prefix: | ofc_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Line of Credit Facility, Aggregate Maximum Borrowing Capacity + References No definition available. + Details
Name: | ofc_LineofCreditFacilityAggregateMaximumBorrowingCapacity
Namespace Prefix: | ofc_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Line of Credit Facility, Extension Fee Percentage + References No definition available. + Details
Name: | ofc_LineofCreditFacilityExtensionFeePercentage
Namespace Prefix: | ofc_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Line of Credit Facility, Accordion Feature, Increase Limit + References No definition available. + Details
Name: | ofc_LineofCreditFacilityIncreasetoMaximumBorrowingCapacity
Namespace Prefix: | ofc_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Line of Credit Facility, Maturity Date Extension, Number of Extensions + References No definition available. + Details
Name: | ofc_LineofCreditFacilityMaturityDateExtensionNumberofExtensions
Namespace Prefix: | ofc_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Percentage points added to the reference rate to compute the variable rate on the debt instrument. + References No definition available. + Details
Name: | us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Face (par) amount of debt instrument at time of issuance. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 835 -SubTopic 30 -Section 55 -Paragraph 8 -URI http://asc.fasb.org/extlink&oid=34725769&loc=d3e28878-108400 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 835 -SubTopic 30 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6451184&loc=d3e28551-108399 + Details
Name: | us-gaap_DebtInstrumentFaceAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Effective interest rate for the funds borrowed under the debt agreement considering interest compounding and original issue discount or premium. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.22(a)(1)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 835 -SubTopic 30 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6451184&loc=d3e28551-108399 + Details
Name: | us-gaap_DebtInstrumentInterestRateEffectivePercentage
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Contractual interest rate for funds borrowed, under the debt agreement. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.22(a)(1)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
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_DebtInstrumentLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage price of original principal amount of debt at which debt can be redeemed by the issuer. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 470 -Section 50 -Paragraph 3 -Subparagraph e -URI http://asc.fasb.org/extlink&oid=6479336&loc=d3e64711-112823 + Details
Name: | us-gaap_DebtInstrumentRedemptionPricePercentage
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition The amount of debt discount that was originally recognized at the issuance of the instrument that has yet to be amortized. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 835 -SubTopic 30 -Section 45 -Paragraph 1A -URI http://asc.fasb.org/extlink&oid=6451184&loc=d3e28541-108399 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 835 -SubTopic 30 -Section 55 -Paragraph 8 -URI http://asc.fasb.org/extlink&oid=34725769&loc=d3e28878-108400 + Details
Name: | us-gaap_DebtInstrumentUnamortizedDiscount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Weighted average interest rate of debt outstanding. + References No definition available. + Details
Name: | us-gaap_DebtWeightedAverageInterestRate
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Gross amount of debt extinguished. + References No definition available. + Details
Name: | us-gaap_ExtinguishmentOfDebtAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Difference between the fair value of payments made and the carrying amount of debt which is extinguished prior to maturity. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 470 -SubTopic 50 -Section 40 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=49170532&loc=d3e12317-112629 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=56944662&loc=d3e3602-108585 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 470 -SubTopic 50 -Section 40 -Paragraph 4 -URI http://asc.fasb.org/extlink&oid=49170532&loc=d3e12355-112629 + Details
Name: | us-gaap_GainsLossesOnExtinguishmentOfDebt
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Average amount borrowed under the credit facility during the period. + References No definition available. + Details
Name: | us-gaap_LineOfCreditFacilityAverageOutstandingAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The fee, expressed as a percentage of the line of credit facility, for the line of credit facility regardless of whether the facility has been used. + References No definition available. + Details
Name: | us-gaap_LineOfCreditFacilityCommitmentFeePercentage
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.19(b),22(b)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding). + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.19(b),22(b)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition The cash inflow from additional borrowings, net of cash paid to third parties in connection with debt origination. + References No definition available. + Details
Name: | us-gaap_ProceedsFromDebtNetOfIssuanceCosts
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The cash inflow during the period from additional borrowings in aggregate debt. Includes proceeds from short-term and long-term debt. + References No definition available. + Details
Name: | us-gaap_ProceedsFromIssuanceOfDebt
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The cash outflow during the period from the repayment of aggregate short-term and long-term debt. Excludes payment of capital lease obligations. + References No definition available. + Details
Name: | us-gaap_RepaymentsOfDebt
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Details
Name: | us-gaap_DebtInstrumentAxis=ofc_TermCreditFacilityEffectiveFebruary2012Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=ofc_TermCreditFacilityEffectiveAugust2012Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=ofc_TermCreditFacilityEffectiveSeptember2011Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=ofc_Exchangeable425PercentSeniorNotesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=ofc_FixedRateSecuredDebtMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RangeAxis=us-gaap_MinimumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=ofc_CreditFacilityMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_VariableRateAxis=us-gaap_LondonInterbankOfferedRateLIBORMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RangeAxis=us-gaap_MaximumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ExtinguishmentOfDebtAxis=ofc_SecuredLoansDueNovember2015AndJanuary2016Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ExtinguishmentOfDebtAxis=ofc_SecuredLoanDueNovember2015Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ExtinguishmentOfDebtAxis=ofc_SecuredLoanDueJanuary2016Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_CreditFacilityAxis=us-gaap_RevolvingCreditFacilityMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LongtermDebtTypeAxis=us-gaap_LineOfCreditMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_CreditFacilityAxis=ofc_TermLoanFacilitiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LongtermDebtTypeAxis=us-gaap_UnsecuredDebtMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=ofc_TermCreditFacilityEffectiveDecember2015Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LongtermDebtTypeAxis=us-gaap_SeniorNotesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=ofc_A3.70SeniorNotesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_VariableRateAxis=ofc_AdjustedTreasuryMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=ofc_FivePercentSeniorNotesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=ofc_A3.60SeniorNotesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=ofc_A5.250SeniorNotesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ofc_RealEstatePropertyDisposalAxis=ofc_OperatingPropertiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis=ofc_December2013PortfolioConveyanceMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis=ofc_Number15000and15010ConferenceCenterDriveMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementGeographicalAxis=ofc_NorthernVirginiaMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |