XML 83 R54.htm IDEA: XBRL DOCUMENT
v3.6.0.2

Summary of Significant Accounting Policies (Details 2) - USD ($) $ in Thousands | 12 Months Ended
--- | ---
Dec. 31, 2016 | Dec. 31, 2015 | Dec. 31, 2014
Accounting Policies [Abstract] |  |  |
Minimum adjusted taxable income to be distributed to shareholders to qualify as a REIT (as a percent) | 90.00% |  |
Subsequent period during which entity would be disqualified as a REIT if during any tax year entity fails to qualify as a REIT (in years) | 4 years |  |
Change in Accounting Estimate [Line Items] |  |  |
Approximate amount by which basis of assets and liabilities for tax reporting purposes is higher than amount reported on consolidated balance sheet | $ 9,000 |  |
Deferred lease related compensation costs | 1,100 | $ 1,200 | $ 1,300
Future minimum payments due | $ 91,249 |  |
Common Shares [Member] |  |  |
Change in Accounting Estimate [Line Items] |  |  |
Ordinary income (as a percent) | 48.00% | 38.30% | 64.50%
Long-term capital gain (as a percent) | 0.00% | 61.70% | 6.50%
Return of capital (as a percent) | 52.00% | 0.00% | 29.00%
Preferred Shares [Member] |  |  |
Change in Accounting Estimate [Line Items] |  |  |
Ordinary income (as a percent) | 100.00% | 38.30% | 90.90%
Long-term capital gain (as a percent) | 0.00% | 61.70% | 9.10%
Return of capital (as a percent) | 0.00% | 0.00% | 0.00%
Ground Leases [Member] |  |  |
Change in Accounting Estimate [Line Items] |  |  |
Future minimum payments due | $ 90,900 |  |
Accounting Standards Update 2014-09 [Member] |  |  |
Change in Accounting Estimate [Line Items] |  |  |
Effect of change on net income | $ 18,000 |  |

X
- Definition Represents the approximate amount by which basis of assets and liabilities for tax reporting purposes are higher than the amount reported on consolidated balance sheet. + References No definition available. + Details
Name: | ofc_ApproximateAmountbywhichNetBasisofAssetsandLiabilitiesforTaxReportingPurposesisHigherthanAmountReportedonConsolidatedBalanceSheet
Namespace Prefix: | ofc_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Compensation and Indirect Costs Capitalized, Deferred Leasing Costs + References No definition available. + Details
Name: | ofc_CompensationandIndirectCostsCapitalizedDeferredLeasingCosts
Namespace Prefix: | ofc_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Represents the percentage of aggregate dividends declared during the period treated as a long-term capital gain for federal tax purposes. + References No definition available. + Details
Name: | ofc_DividendsDeclaredLongTermCapitalGainPercentage
Namespace Prefix: | ofc_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Represents the percentage of aggregate dividends declared during the period treated as ordinary income for federal tax purposes. + References No definition available. + Details
Name: | ofc_DividendsDeclaredOrdinaryIncomePercentage
Namespace Prefix: | ofc_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Represents the percentage of aggregate dividends declared during the period treated as return of capital for federal tax purposes. + References No definition available. + Details
Name: | ofc_DividendsDeclaredReturnOfCapitalPercentage
Namespace Prefix: | ofc_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Represents the minimum percentage of adjusted taxable income required to be distributed to shareholders for qualifying as a real estate investment trust. + References No definition available. + Details
Name: | ofc_MinimumPercentageOfTaxableIncomeToBeDistributedAsDividendToMaintainQualificationAsReit
Namespace Prefix: | ofc_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Represents the subsequent number of years during which the entity would be disqualified as a real estate investment trust, if during any tax year the entity fails to qualify as a real estate investment trust. + References No definition available. + Details
Name: | ofc_SubsequentDisqualificationPeriodIfFailedToQualifyAsReit
Namespace Prefix: | ofc_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- References No definition available. + Details
Name: | us-gaap_AccountingPoliciesAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

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_ChangeInAccountingEstimateLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of the effect of a change in accounting principle on net income. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 250 -SubTopic 10 -Section 50 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=64853466&loc=d3e22583-107794 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 250 -SubTopic 10 -Section 50 -Paragraph 1 -Subparagraph (b)(2) -URI http://asc.fasb.org/extlink&oid=64853466&loc=d3e22499-107794 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 250 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=64853466&loc=d3e22580-107794 + Details
Name: | us-gaap_NewAccountingPronouncementOrChangeInAccountingPrincipleEffectOfChangeOnNetIncome
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of required minimum rental payments for leases having an initial or remaining non-cancelable letter-terms in excess of one year. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 840 -SubTopic 10 -Section 55 -Paragraph 40 -Subparagraph (Note 3) -URI http://asc.fasb.org/extlink&oid=6584154&loc=d3e38371-112697 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 840 -SubTopic 20 -Section 50 -Paragraph 2 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=6453985&loc=d3e41502-112717 + Details
Name: | us-gaap_OperatingLeasesFutureMinimumPaymentsDue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Details
Name: | us-gaap_StatementClassOfStockAxis=us-gaap_CommonStockMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementClassOfStockAxis=us-gaap_PreferredStockMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LeaseArrangementTypeAxis=ofc_GroundLeasesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_AdjustmentsForNewAccountingPronouncementsAxis=us-gaap_AccountingStandardsUpdate201409Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |