XML 47 R97.htm IDEA: XBRL DOCUMENT
v2.4.1.9

Quarterly Data (Unaudited) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified | 3 Months Ended | 12 Months Ended
--- | --- | ---
Dec. 31, 2014 | Sep. 30, 2014 | Jun. 30, 2014 | Mar. 31, 2014 | Dec. 31, 2013 | Sep. 30, 2013 | Jun. 30, 2013 | Mar. 31, 2013 | Dec. 31, 2014 | Dec. 31, 2013 | Dec. 31, 2012
Revenues | $ 146,971 us-gaap_Revenues | $ 153,015 us-gaap_Revenues | $ 139,820 us-gaap_Revenues | $ 146,667 us-gaap_Revenues | $ 128,802 us-gaap_Revenues | $ 131,812 us-gaap_Revenues | $ 136,527 us-gaap_Revenues | $ 126,219 us-gaap_Revenues | $ 586,473 us-gaap_Revenues |  | $ 523,360 us-gaap_Revenues |  | $ 508,135 us-gaap_Revenues |
Operating income (loss) | 37,148 us-gaap_OperatingIncomeLoss | 37,422 us-gaap_OperatingIncomeLoss | 31,836 us-gaap_OperatingIncomeLoss | 25,206 us-gaap_OperatingIncomeLoss | 34,843 us-gaap_OperatingIncomeLoss | 30,673 us-gaap_OperatingIncomeLoss | 40,229 us-gaap_OperatingIncomeLoss | 36,165 us-gaap_OperatingIncomeLoss | 131,612 us-gaap_OperatingIncomeLoss |  | 141,910 us-gaap_OperatingIncomeLoss |  | 89,066 us-gaap_OperatingIncomeLoss |
Income (loss) from continuing operations | 5,874 us-gaap_IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest | 13,727 us-gaap_IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest | 9,248 us-gaap_IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest | 5,660 us-gaap_IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest | 14,432 us-gaap_IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest | 10,974 us-gaap_IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest | (232)us-gaap_IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest | 11,662 us-gaap_IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest | 34,509 us-gaap_IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest |  | 36,836 us-gaap_IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest |  | 7,967 us-gaap_IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest |
Discontinued operations | 22 us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTax | 191 us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTax | (198)us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTax | 11 us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTax | 71,907 us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTax | (12,974)us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTax | (4,502)us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTax | 1,261 us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTax | 26 us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTax |  | 55,692 us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTax |  | 12,353 us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTax |
Net income | 5,937 us-gaap_ProfitLoss | 24,548 us-gaap_ProfitLoss | 9,050 us-gaap_ProfitLoss | 5,671 us-gaap_ProfitLoss | 92,672 us-gaap_ProfitLoss | (2,000)us-gaap_ProfitLoss | (4,405)us-gaap_ProfitLoss | 15,277 us-gaap_ProfitLoss | 45,206 us-gaap_ProfitLoss |  | 101,544 us-gaap_ProfitLoss |  | 20,341 us-gaap_ProfitLoss |
Net (income) loss attributable to noncontrolling interests in consolidated entities | (1,033)us-gaap_NetIncomeLossAttributableToNoncontrollingInterest | (1,828)us-gaap_NetIncomeLossAttributableToNoncontrollingInterest | (1,160)us-gaap_NetIncomeLossAttributableToNoncontrollingInterest | (930)us-gaap_NetIncomeLossAttributableToNoncontrollingInterest | (5,656)us-gaap_NetIncomeLossAttributableToNoncontrollingInterest | (964)us-gaap_NetIncomeLossAttributableToNoncontrollingInterest | (960)us-gaap_NetIncomeLossAttributableToNoncontrollingInterest | (257)us-gaap_NetIncomeLossAttributableToNoncontrollingInterest |  |  |  |  |  |
Net income | 4,904 us-gaap_NetIncomeLoss | 22,720 us-gaap_NetIncomeLoss | 7,890 us-gaap_NetIncomeLoss | 4,741 us-gaap_NetIncomeLoss | 87,016 us-gaap_NetIncomeLoss | (2,964)us-gaap_NetIncomeLoss | (5,365)us-gaap_NetIncomeLoss | 15,020 us-gaap_NetIncomeLoss | 40,255 us-gaap_NetIncomeLoss |  | 93,707 us-gaap_NetIncomeLoss |  | 20,977 us-gaap_NetIncomeLoss |
Preferred share/ unit dividends/ distributions | (3,552)us-gaap_PreferredStockDividendsIncomeStatementImpact | (3,553)us-gaap_PreferredStockDividendsIncomeStatementImpact | (4,344)us-gaap_PreferredStockDividendsIncomeStatementImpact | (4,490)us-gaap_PreferredStockDividendsIncomeStatementImpact | (4,490)us-gaap_PreferredStockDividendsIncomeStatementImpact | (4,490)us-gaap_PreferredStockDividendsIncomeStatementImpact | (4,885)us-gaap_PreferredStockDividendsIncomeStatementImpact | (6,106)us-gaap_PreferredStockDividendsIncomeStatementImpact | (15,939)us-gaap_PreferredStockDividendsIncomeStatementImpact |  | (19,971)us-gaap_PreferredStockDividendsIncomeStatementImpact |  | (20,844)us-gaap_PreferredStockDividendsIncomeStatementImpact |
Issuance costs associated with redeemed preferred shares | 0 us-gaap_OtherPreferredStockDividendsAndAdjustments | 0 us-gaap_OtherPreferredStockDividendsAndAdjustments | (1,769)us-gaap_OtherPreferredStockDividendsAndAdjustments | 0 us-gaap_OtherPreferredStockDividendsAndAdjustments | 0 us-gaap_OtherPreferredStockDividendsAndAdjustments | 0 us-gaap_OtherPreferredStockDividendsAndAdjustments | (2,904)us-gaap_OtherPreferredStockDividendsAndAdjustments | 0 us-gaap_OtherPreferredStockDividendsAndAdjustments | (1,769)us-gaap_OtherPreferredStockDividendsAndAdjustments |  | (2,904)us-gaap_OtherPreferredStockDividendsAndAdjustments |  | (1,827)us-gaap_OtherPreferredStockDividendsAndAdjustments |
Net income (loss) attributable to COPT common shareholders | 1,352 us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic | 19,167 us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic | 1,777 us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic | 251 us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic | 82,526 us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic | (7,454)us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic | (13,154)us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic | 8,914 us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic | 22,547 us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic |  | 70,832 us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic |  | (1,694)us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic |
Basic earnings per common share/unit (in dollars per share/unit) | $ 0.01 us-gaap_EarningsPerShareBasic | $ 0.22 us-gaap_EarningsPerShareBasic | $ 0.02 us-gaap_EarningsPerShareBasic | $ 0.00 us-gaap_EarningsPerShareBasic | $ 0.94 us-gaap_EarningsPerShareBasic | $ (0.09)us-gaap_EarningsPerShareBasic | $ (0.16)us-gaap_EarningsPerShareBasic | $ 0.11 us-gaap_EarningsPerShareBasic | $ 0.25 us-gaap_EarningsPerShareBasic | [1] | $ 0.83 us-gaap_EarningsPerShareBasic | [1] | $ (0.03)us-gaap_EarningsPerShareBasic | [1]
Diluted earnings per common share/unit (in dollars per share/unit) | $ 0.01 us-gaap_EarningsPerShareDiluted | $ 0.22 us-gaap_EarningsPerShareDiluted | $ 0.02 us-gaap_EarningsPerShareDiluted | $ 0.00 us-gaap_EarningsPerShareDiluted | $ 0.94 us-gaap_EarningsPerShareDiluted | $ (0.09)us-gaap_EarningsPerShareDiluted | $ (0.16)us-gaap_EarningsPerShareDiluted | $ 0.11 us-gaap_EarningsPerShareDiluted | $ 0.25 us-gaap_EarningsPerShareDiluted | [1] | $ 0.83 us-gaap_EarningsPerShareDiluted | [1] | $ (0.03)us-gaap_EarningsPerShareDiluted | [1]
Corporate Office Properties, L.P. |  |  |  |  |  |  |  |  |  |  |  |  |  |
Revenues | 146,971 us-gaap_Revenues / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | 153,015 us-gaap_Revenues / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | 139,820 us-gaap_Revenues / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | 146,667 us-gaap_Revenues / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | 128,802 us-gaap_Revenues / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | 131,812 us-gaap_Revenues / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | 136,527 us-gaap_Revenues / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | 126,219 us-gaap_Revenues / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | 586,473 us-gaap_Revenues / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |  | 523,360 us-gaap_Revenues / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |  | 508,135 us-gaap_Revenues / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |
Operating income (loss) | 37,148 us-gaap_OperatingIncomeLoss / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | 37,422 us-gaap_OperatingIncomeLoss / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | 31,836 us-gaap_OperatingIncomeLoss / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | 25,206 us-gaap_OperatingIncomeLoss / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | 34,843 us-gaap_OperatingIncomeLoss / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | 30,673 us-gaap_OperatingIncomeLoss / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | 40,229 us-gaap_OperatingIncomeLoss / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | 36,165 us-gaap_OperatingIncomeLoss / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | 131,612 us-gaap_OperatingIncomeLoss / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |  | 141,910 us-gaap_OperatingIncomeLoss / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |  | 89,066 us-gaap_OperatingIncomeLoss / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |
Income (loss) from continuing operations | 5,874 us-gaap_IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | 13,727 us-gaap_IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | 9,248 us-gaap_IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | 5,660 us-gaap_IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | 14,432 us-gaap_IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | 10,974 us-gaap_IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | (232)us-gaap_IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | 11,662 us-gaap_IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | 34,509 us-gaap_IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |  | 36,836 us-gaap_IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |  | 7,967 us-gaap_IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |
Discontinued operations | 22 us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTax / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | 191 us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTax / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | (198)us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTax / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | 11 us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTax / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | 71,907 us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTax / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | (12,974)us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTax / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | (4,502)us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTax / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | 1,261 us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTax / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | 26 us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTax / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |  | 55,692 us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTax / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |  | 12,353 us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTax / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |
Net income | 5,937 us-gaap_ProfitLoss / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | 24,548 us-gaap_ProfitLoss / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | 9,050 us-gaap_ProfitLoss / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | 5,671 us-gaap_ProfitLoss / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | 92,672 us-gaap_ProfitLoss / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | (2,000)us-gaap_ProfitLoss / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | (4,405)us-gaap_ProfitLoss / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | 15,277 us-gaap_ProfitLoss / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | 45,206 us-gaap_ProfitLoss / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |  | 101,544 us-gaap_ProfitLoss / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |  | 20,341 us-gaap_ProfitLoss / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |
Net (income) loss attributable to noncontrolling interests in consolidated entities | (805)us-gaap_NetIncomeLossAttributableToNoncontrollingInterest / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | (897)us-gaap_NetIncomeLossAttributableToNoncontrollingInterest / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | (837)us-gaap_NetIncomeLossAttributableToNoncontrollingInterest / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | (737)us-gaap_NetIncomeLossAttributableToNoncontrollingInterest / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | (1,735)us-gaap_NetIncomeLossAttributableToNoncontrollingInterest / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | (1,035)us-gaap_NetIncomeLossAttributableToNoncontrollingInterest / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | (1,473)us-gaap_NetIncomeLossAttributableToNoncontrollingInterest / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | 336 us-gaap_NetIncomeLossAttributableToNoncontrollingInterest / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | (3,276)us-gaap_NetIncomeLossAttributableToNoncontrollingInterest / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |  | (3,907)us-gaap_NetIncomeLossAttributableToNoncontrollingInterest / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |  | 507 us-gaap_NetIncomeLossAttributableToNoncontrollingInterest / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |
Net income | 5,132 us-gaap_NetIncomeLoss / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | 23,651 us-gaap_NetIncomeLoss / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | 8,213 us-gaap_NetIncomeLoss / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | 4,934 us-gaap_NetIncomeLoss / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | 90,937 us-gaap_NetIncomeLoss / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | (3,035)us-gaap_NetIncomeLoss / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | (5,878)us-gaap_NetIncomeLoss / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | 15,613 us-gaap_NetIncomeLoss / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | 41,930 us-gaap_NetIncomeLoss / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |  | 97,637 us-gaap_NetIncomeLoss / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |  | 20,848 us-gaap_NetIncomeLoss / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |
Preferred share/ unit dividends/ distributions | (3,717)us-gaap_PreferredStockDividendsIncomeStatementImpact / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | (3,718)us-gaap_PreferredStockDividendsIncomeStatementImpact / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | (4,509)us-gaap_PreferredStockDividendsIncomeStatementImpact / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | (4,655)us-gaap_PreferredStockDividendsIncomeStatementImpact / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | (4,655)us-gaap_PreferredStockDividendsIncomeStatementImpact / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | (4,655)us-gaap_PreferredStockDividendsIncomeStatementImpact / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | (5,050)us-gaap_PreferredStockDividendsIncomeStatementImpact / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | (6,271)us-gaap_PreferredStockDividendsIncomeStatementImpact / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | (16,599)us-gaap_PreferredStockDividendsIncomeStatementImpact / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |  | (20,631)us-gaap_PreferredStockDividendsIncomeStatementImpact / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |  | (21,504)us-gaap_PreferredStockDividendsIncomeStatementImpact / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |
Issuance costs associated with redeemed preferred shares | 0 us-gaap_OtherPreferredStockDividendsAndAdjustments / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | 0 us-gaap_OtherPreferredStockDividendsAndAdjustments / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | (1,769)us-gaap_OtherPreferredStockDividendsAndAdjustments / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | 0 us-gaap_OtherPreferredStockDividendsAndAdjustments / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | 0 us-gaap_OtherPreferredStockDividendsAndAdjustments / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | 0 us-gaap_OtherPreferredStockDividendsAndAdjustments / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | (2,904)us-gaap_OtherPreferredStockDividendsAndAdjustments / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | 0 us-gaap_OtherPreferredStockDividendsAndAdjustments / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | (1,769)us-gaap_OtherPreferredStockDividendsAndAdjustments / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |  | (2,904)us-gaap_OtherPreferredStockDividendsAndAdjustments / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |  | (1,827)us-gaap_OtherPreferredStockDividendsAndAdjustments / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |
Net income (loss) attributable to COPT common shareholders | $ 1,415 us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | $ 19,933 us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | $ 1,935 us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | $ 279 us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | $ 86,282 us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | $ (7,690)us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | $ (13,832)us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | $ 9,342 us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | $ 23,562 us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |  | $ 74,102 us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |  | $ (2,483)us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |
Basic earnings per common share/unit (in dollars per share/unit) | $ 0.01 us-gaap_EarningsPerShareBasic / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | $ 0.22 us-gaap_EarningsPerShareBasic / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | $ 0.02 us-gaap_EarningsPerShareBasic / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | $ 0.00 us-gaap_EarningsPerShareBasic / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | $ 0.94 us-gaap_EarningsPerShareBasic / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | $ (0.09)us-gaap_EarningsPerShareBasic / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | $ (0.16)us-gaap_EarningsPerShareBasic / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | $ 0.11 us-gaap_EarningsPerShareBasic / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | $ 0.25 us-gaap_EarningsPerShareBasic / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | [2] | $ 0.83 us-gaap_EarningsPerShareBasic / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | [2] | $ (0.04)us-gaap_EarningsPerShareBasic / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | [2]
Diluted earnings per common share/unit (in dollars per share/unit) | $ 0.01 us-gaap_EarningsPerShareDiluted / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | $ 0.22 us-gaap_EarningsPerShareDiluted / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | $ 0.02 us-gaap_EarningsPerShareDiluted / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | $ 0.00 us-gaap_EarningsPerShareDiluted / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | $ 0.94 us-gaap_EarningsPerShareDiluted / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | $ (0.09)us-gaap_EarningsPerShareDiluted / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | $ (0.16)us-gaap_EarningsPerShareDiluted / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | $ 0.11 us-gaap_EarningsPerShareDiluted / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | $ 0.25 us-gaap_EarningsPerShareDiluted / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | [2] | $ 0.83 us-gaap_EarningsPerShareDiluted / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | [2] | $ (0.04)us-gaap_EarningsPerShareDiluted / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | [2]
[1] | Basic and diluted earnings per common share are calculated based on amounts attributable to common shareholders of Corporate Office Properties Trust.
[2] | Basic and diluted earnings per common unit are calculated based on amounts attributable to common unitholders of Corporate Office Properties, L.P.

X
- Definition The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 260 -SubTopic 10 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6371337&loc=d3e3550-109257 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 260 -SubTopic 10 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=7655603&loc=d3e1252-109256 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 260 -SubTopic 10 -Section 55 -Paragraph 52 -URI http://asc.fasb.org/extlink&oid=32703322&loc=d3e4984-109258 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 225 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03.21) -URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688 Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 225 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-04.19) -URI http://asc.fasb.org/extlink&oid=6879464&loc=d3e573970-122913 Reference 6: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 225 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-04.23) -URI http://asc.fasb.org/extlink&oid=6879574&loc=d3e536633-122882 Reference 7: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Paragraph 18 -Article 7 Reference 8: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 20 -Article 5 Reference 9: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Paragraph 21 -Article 9 + Details
Name: | us-gaap_EarningsPerShareBasic
Namespace Prefix: | us-gaap_
Data Type: | num:perShareItemType
Balance Type: | na
Period Type: | duration

X
- Definition The amount of net income (loss) for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 260 -SubTopic 10 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=7655603&loc=d3e1252-109256 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 225 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03.21) -URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Paragraph 18 -Article 7 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 20 -Article 5 Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Paragraph 21 -Article 9 + Details
Name: | us-gaap_EarningsPerShareDiluted
Namespace Prefix: | us-gaap_
Data Type: | num:perShareItemType
Balance Type: | na
Period Type: | duration

X
- Definition This element represents the income or loss from continuing operations attributable to the economic entity which may also be defined as revenue less expenses and taxes from ongoing operations before extraordinary items, and noncontrolling interest. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 810 -SubTopic 10 -Section 45 -Paragraph 19 -URI http://asc.fasb.org/extlink&oid=7656940&loc=SL4569616-111683 + Details
Name: | us-gaap_IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of income (loss) from a disposal group, net of income tax before extraordinary items allocable to noncontrolling interests. Includes, net of tax, income (loss) from operations during the phase-out period, gain (loss) on disposal, provision (or any reversals of earlier provisions) for loss on disposal, and adjustments of a prior period gain (loss) on disposal. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 205 -SubTopic 20 -Section 45 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=6892542&loc=d3e957-107759 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 225 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-04.12) -URI http://asc.fasb.org/extlink&oid=6879464&loc=d3e573970-122913 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Paragraph 13 -Article 7 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 205 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=6360339&loc=d3e1361-107760 Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 225 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03.14) -URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688 Reference 6: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 15 -Article 5 + Details
Name: | us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTax
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The portion of profit or loss for the period, net of income taxes, which is attributable to the parent. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3602-108585 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 260 -SubTopic 10 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6371337&loc=d3e3550-109257 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Other Comprehensive Income -URI http://asc.fasb.org/extlink&oid=6519514 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Net Income -URI http://asc.fasb.org/extlink&oid=6518256 Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 225 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-04.19) -URI http://asc.fasb.org/extlink&oid=6879464&loc=d3e573970-122913 Reference 6: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 225 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03.18) -URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688 Reference 7: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 225 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-04.22) -URI http://asc.fasb.org/extlink&oid=6879464&loc=d3e573970-122913 Reference 8: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 19 -Article 5 Reference 9: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Paragraph 20 -Article 9 + Details
Name: | us-gaap_NetIncomeLoss
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of Net Income (Loss) attributable to noncontrolling interest. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 810 -SubTopic 10 -Section 50 -Paragraph 1A -URI http://asc.fasb.org/extlink&oid=18733093&loc=SL4573702-111684 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 810 -SubTopic 10 -Section 55 -Paragraph 4J -URI http://asc.fasb.org/extlink&oid=35736750&loc=SL4591551-111686 + Details
Name: | us-gaap_NetIncomeLossAttributableToNoncontrollingInterest
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Net income after adjustments for dividends on preferred stock (declared in the period) and/or cumulative preferred stock (accumulated for the period). + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 260 -SubTopic 10 -Section 45 -Paragraph 11 -URI http://asc.fasb.org/extlink&oid=7655603&loc=d3e1377-109256 + Details
Name: | us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The net result for the period of deducting operating expenses from operating revenues. + References No definition available. + Details
Name: | us-gaap_OperatingIncomeLoss
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Other preferred stock dividends and adjustments, not otherwise defined in the taxonomy, that are necessary to adjust net income to obtain net income applicable to common stockholders. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 260 -SubTopic 10 -Section 45 -Paragraph 11 -URI http://asc.fasb.org/extlink&oid=7655603&loc=d3e1377-109256 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Staff Accounting Bulletin (SAB) -Number Topic 5 -Section Q + Details
Name: | us-gaap_OtherPreferredStockDividendsAndAdjustments
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The amount of preferred stock dividends that is an adjustment to net income apportioned to common stockholders. + References No definition available. + Details
Name: | us-gaap_PreferredStockDividendsIncomeStatementImpact
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The consolidated profit or loss for the period, net of income taxes, including the portion attributable to the noncontrolling interest. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 810 -SubTopic 10 -Section 55 -Paragraph 4K -URI http://asc.fasb.org/extlink&oid=35736750&loc=SL4591552-111686 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 810 -SubTopic 10 -Section 45 -Paragraph 19 -URI http://asc.fasb.org/extlink&oid=7656940&loc=SL4569616-111683 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 810 -SubTopic 10 -Section 50 -Paragraph 1A -Subparagraph (a),(c) -URI http://asc.fasb.org/extlink&oid=18733093&loc=SL4573702-111684 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 810 -SubTopic 10 -Section 55 -Paragraph 4J -URI http://asc.fasb.org/extlink&oid=35736750&loc=SL4591551-111686 + Details
Name: | us-gaap_ProfitLoss
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss). + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 225 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03.1) -URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 1 -Article 5 + Details
Name: | us-gaap_Revenues
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Details
Name: | dei_LegalEntityAxis=us-gaap_SubsidiariesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |