$CDP
COPT Defense Properties Stock $cdp

$cdp Overview Financials Valuation SEC Filings Company Website

2014 Q4 Form 10-Q Financial Statement

#000086054614000043 Filed on October 28, 2014

Income Statement

Concept	2014 Q4	2014 Q3	2013 Q3
Revenue	$147.0M	$153.0M	$131.8M
YoY Change	14.11%	16.09%	5.39%
Cost Of Revenue	$68.00M	$33.59M	$16.31M
YoY Change	43.16%	106.02%	13.16%
Gross Profit	$78.90M	$119.4M	$115.5M
YoY Change	14.85%	3.39%	4.38%
Gross Profit Margin	53.68%	78.05%	87.63%
Selling, General & Admin	$8.900M	$7.211M	$8.027M
YoY Change	5.95%	-10.17%	25.87%
% of Gross Profit	11.28%	6.04%	6.95%
Research & Development	$1.500M	$1.400M	$1.400M
YoY Change	7.14%	0.0%	-12.5%
% of Gross Profit	1.9%	1.17%	1.21%
Depreciation & Amortization	$31.90M	$30.80M	$29.80M
YoY Change	0.31%	3.36%	-4.49%
% of Gross Profit	40.43%	25.79%	25.8%
Operating Expenses	$41.70M	$7.211M	$8.027M
YoY Change	13.62%	-10.17%	25.87%
Operating Profit	$37.15M	$37.42M	$30.67M
YoY Change	6.62%	22.0%	-382.86%
Interest Expense	-$22.10M	-$23.40M	-$19.30M
YoY Change	78.23%	21.24%	-13.84%
% of Operating Profit	-59.49%	-62.53%	-62.92%
Other Income/Expense, Net
YoY Change
Pretax Income	$5.900M	$13.64M	$10.95M
YoY Change	-80.33%	24.48%	-134.38%
Income Tax	$100.0K	$101.0K	$24.00K
% Of Pretax Income	1.69%	0.74%	0.22%
Net Earnings	$4.904M	$22.72M	-$2.964M
YoY Change	-94.36%	-866.53%	-84.53%
Net Earnings / Revenue	3.34%	14.85%	-2.25%
Basic Earnings Per Share	$0.01	$0.22	-$0.09
Diluted Earnings Per Share	$0.01	$0.22	-$0.09
COMMON SHARES
Basic Shares Outstanding	87.71M shares	87.29M shares	86.76M shares
Diluted Shares Outstanding		87.49M shares	86.76M shares

Balance Sheet

Concept	2014 Q4	2014 Q3	2013 Q3
SHORT-TERM ASSETS
Cash & Short-Term Investments	$6.100M	$40.00M	$27.30M
YoY Change	-88.79%	46.52%	446.0%
Cash & Equivalents	$6.077M	$40.02M	$27.32M
Short-Term Investments
Other Short-Term Assets
YoY Change
Inventory	$14.30M		$134.0M
Prepaid Expenses
Receivables	$30.70M	$20.20M	$17.70M
Other Receivables	$0.00	$0.00	$0.00
Total Short-Term Assets	$51.10M	$60.20M	$179.0M
YoY Change	-37.22%	-66.37%	-28.74%
LONG-TERM ASSETS
Property, Plant & Equipment	$6.637M	$6.527M	$6.705M
YoY Change	1.24%	-2.65%	-22.55%
Goodwill
YoY Change
Intangibles	$43.85M	$48.30M	$64.37M
YoY Change	-25.99%	-24.97%	-20.59%
Long-Term Investments	$2.368M	$2.240M	$4.928M
YoY Change	4.87%	-54.55%
Other Assets	$92.40M	$107.9M	$107.7M
YoY Change	-8.79%	0.19%	35.13%
Total Long-Term Assets	$3.613B	$3.620B	$3.577B
YoY Change	1.82%	1.21%	6.88%
TOTAL ASSETS
Total Short-Term Assets	$51.10M	$60.20M	$179.0M
Total Long-Term Assets	$3.613B	$3.620B	$3.577B
Total Assets	$3.664B	$3.680B	$3.756B
YoY Change	0.94%	-2.01%	4.39%
SHORT-TERM LIABILITIES
YoY Change
Accounts Payable	$123.0M	$123.9M	$85.30M
YoY Change	24.49%	45.25%	-2.4%
Accrued Expenses
YoY Change
Deferred Revenue
YoY Change
Short-Term Debt	$0.00	$0.00	$0.00
YoY Change
Long-Term Debt Due
YoY Change
Total Short-Term Liabilities	$183.9M	$185.3M	$142.9M
YoY Change	15.37%	29.67%	1.28%
LONG-TERM LIABILITIES
Long-Term Debt	$1.914B	$2.050B	$2.135B
YoY Change	-0.71%	-3.98%	-1.58%
Other Long-Term Liabilities	$27.00M	$28.90M	$26.80M
YoY Change	-3.23%	7.84%	-27.57%
Total Long-Term Liabilities	$1.941B	$2.079B	$2.162B
YoY Change	-0.75%	-3.83%	-2.02%
TOTAL LIABILITIES
Total Short-Term Liabilities	$183.9M	$185.3M	$142.9M
Total Long-Term Liabilities	$1.941B	$2.079B	$2.162B
Total Liabilities	$2.125B	$2.264B	$2.305B
YoY Change	0.47%	-1.76%	-1.82%
SHAREHOLDERS EQUITY
Retained Earnings
YoY Change
Common Stock	$933.0K	$877.0K	$874.0K
YoY Change	6.75%	0.34%	21.05%
Preferred Stock
YoY Change
Treasury Stock (at cost)
YoY Change
Treasury Stock Shares
Shareholders Equity	$1.451B	$1.330B	$1.365B
YoY Change
Total Liabilities & Shareholders Equity	$3.664B	$3.680B	$3.756B
YoY Change	0.94%	-2.01%	4.39%

Cashflow Statement

Concept	2014 Q4	2014 Q3	2013 Q3
OPERATING ACTIVITIES
Net Income	$4.904M	$22.72M	-$2.964M
YoY Change	-94.36%	-866.53%	-84.53%
Depreciation, Depletion And Amortization	$31.90M	$30.80M	$29.80M
YoY Change	0.31%	3.36%	-4.49%
Cash From Operating Activities	$49.70M	$41.20M	$45.50M
YoY Change	-4.42%	-9.45%	63.67%
INVESTING ACTIVITIES
Capital Expenditures	-$66.30M	-$57.00M	-$68.20M
YoY Change	15.3%	-16.42%	-28.66%
Acquisitions
YoY Change
Other Investing Activities	-$6.200M	$60.00M	-$3.300M
YoY Change	-104.98%	-1918.18%	-102.13%
Cash From Investing Activities	-$72.70M	$3.000M	-$71.50M
YoY Change	-208.51%	-104.2%	-220.78%
FINANCING ACTIVITIES
Cash Dividend Paid
YoY Change
Common Stock Issuance & Retirement, Net
YoY Change
Debt Paid & Issued, Net
YoY Change
Cash From Financing Activities	-10.90M	-80.50M	44.20M
YoY Change	-88.15%	-282.13%	-150.98%
NET CHANGE
Cash From Operating Activities	49.70M	41.20M	45.50M
Cash From Investing Activities	-72.70M	3.000M	-71.50M
Cash From Financing Activities	-10.90M	-80.50M	44.20M
Net Change In Cash	-33.90M	-36.30M	18.20M
YoY Change	-225.56%	-299.45%	5966.67%
FREE CASH FLOW
Cash From Operating Activities	$49.70M	$41.20M	$45.50M
Capital Expenditures	-$66.30M	-$57.00M	-$68.20M
Free Cash Flow	$116.0M	$98.20M	$113.7M
YoY Change	5.94%	-13.63%	-7.86%

Facts In Submission

Frame	Concept Type	Concept / XBRL Key	Value	Unit
CY2014Q3	us-gaap	Accounts Payable And Accrued Liabilities Current And Noncurrent AccountsPayableAndAccruedLiabilitiesCurrentAndNoncurrent	123893000	USD
CY2013Q4	us-gaap	Accounts Payable And Accrued Liabilities Current And Noncurrent AccountsPayableAndAccruedLiabilitiesCurrentAndNoncurrent	98785000	USD
CY2013Q4	us-gaap	Accounts Receivable Net AccountsReceivableNet	27000000	USD
CY2014Q3	us-gaap	Accounts Receivable Net AccountsReceivableNet	20180000	USD
CY2013Q4	us-gaap	Accumulated Distributions In Excess Of Net Income AccumulatedDistributionsInExcessOfNetIncome	641868000	USD
CY2014Q3	us-gaap	Accumulated Distributions In Excess Of Net Income AccumulatedDistributionsInExcessOfNetIncome	692978000	USD
CY2013Q4	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	3480000	USD
CY2014Q3	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	871000	USD
CY2014Q3	us-gaap	Additional Paid In Capital AdditionalPaidInCapital	1822283000	USD
CY2013Q4	us-gaap	Additional Paid In Capital AdditionalPaidInCapital	1814015000	USD
	us-gaap	Adjustments To Additional Paid In Capital Tax Effect From Share Based Compensation AdjustmentsToAdditionalPaidInCapitalTaxEffectFromShareBasedCompensation	-122000	USD
CY2014Q3	us-gaap	Allowance For Doubtful Accounts Receivable AllowanceForDoubtfulAccountsReceivable	750000	USD
CY2013Q4	us-gaap	Allowance For Doubtful Accounts Receivable AllowanceForDoubtfulAccountsReceivable	2976000	USD
	us-gaap	Amortization Of Debt Discount Premium AmortizationOfDebtDiscountPremium	1207000	USD
	us-gaap	Amortization Of Debt Discount Premium AmortizationOfDebtDiscountPremium	659000	USD
	us-gaap	Amortization Of Financing Costs AmortizationOfFinancingCosts	4292000	USD
	us-gaap	Amortization Of Financing Costs AmortizationOfFinancingCosts	3646000	USD
CY2013Q3	us-gaap	Asset Impairment Charges AssetImpairmentCharges	5857000	USD
	us-gaap	Asset Impairment Charges AssetImpairmentCharges	5857000	USD
CY2014Q3	us-gaap	Asset Impairment Charges AssetImpairmentCharges	66000	USD
	us-gaap	Asset Impairment Charges AssetImpairmentCharges	1368000	USD
CY2013Q4	us-gaap	Assets Assets	3629952000	USD
CY2014Q3	us-gaap	Assets Assets	3680188000	USD
CY2013Q3	us-gaap	Assets Assets	3755588000	USD
CY2013Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	54373000	USD
CY2014Q3	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	40018000	USD
CY2012Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	10594000	USD
CY2013Q3	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	27318000	USD
	us-gaap	Cash And Cash Equivalents Period Increase Decrease CashAndCashEquivalentsPeriodIncreaseDecrease	16724000	USD
	us-gaap	Cash And Cash Equivalents Period Increase Decrease CashAndCashEquivalentsPeriodIncreaseDecrease	-14355000	USD
CY2013Q4	us-gaap	Commitments And Contingencies CommitmentsAndContingencies		USD
CY2014Q3	us-gaap	Commitments And Contingencies CommitmentsAndContingencies		USD
CY2014Q3	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.2750
	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.825
	us-gaap	Payments Of Dividends Minority Interest PaymentsOfDividendsMinorityInterest	3705000	USD
	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	169000	shares
	us-gaap	Payments To Minority Shareholders PaymentsToMinorityShareholders	811000	USD
	us-gaap	Proceeds From Payments For Trading Securities ProceedsFromPaymentsForTradingSecurities	298000	USD
	ofc	Disposal Group Including Discontinued Operations General And Administrative And Leasing Expenses DisposalGroupIncludingDiscontinuedOperationsGeneralAndAdministrativeAndLeasingExpenses	0	USD
	ofc	Disposal Group Including Discontinued Operations General And Administrative And Leasing Expenses DisposalGroupIncludingDiscontinuedOperationsGeneralAndAdministrativeAndLeasingExpenses	1000	USD
	us-gaap	Payments To Minority Shareholders PaymentsToMinorityShareholders	976000	USD
	ofc	Redeemable Noncontrolling Interest Equity Net Income Loss Attributableto Noncontrolling Interest RedeemableNoncontrollingInterestEquityNetIncomeLossAttributabletoNoncontrollingInterest	888000	USD
	us-gaap	Stock Issued During Period Value Acquisitions StockIssuedDuringPeriodValueAcquisitions	1369000	USD
	us-gaap	Stock Issued During Period Value Conversion Of Units StockIssuedDuringPeriodValueConversionOfUnits	0	USD
	us-gaap	Stock Issued During Period Value Conversion Of Units StockIssuedDuringPeriodValueConversionOfUnits	0	USD
	us-gaap	Stock Issued During Period Value New Issues StockIssuedDuringPeriodValueNewIssues	-7000	USD
	ofc	Operating Partnership Unit Conversion Rate To Shares OperatingPartnershipUnitConversionRateToShares	1	shares
CY2013Q4	us-gaap	Common Stock Par Or Stated Value Per Share CommonStockParOrStatedValuePerShare	0.01
CY2013Q4	us-gaap	Common Stock Shares Authorized CommonStockSharesAuthorized	125000000	shares
CY2014Q3	us-gaap	Common Stock Shares Authorized CommonStockSharesAuthorized	125000000	shares
	us-gaap	Costs And Expenses CostsAndExpenses	287491000	USD
	us-gaap	Costs And Expenses CostsAndExpenses	345038000	USD
CY2014Q3	us-gaap	Costs And Expenses CostsAndExpenses	115593000	USD
CY2013Q3	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.2750
	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.825
CY2014Q3	us-gaap	Common Stock Par Or Stated Value Per Share CommonStockParOrStatedValuePerShare	0.01
CY2013Q4	us-gaap	Common Stock Shares Issued CommonStockSharesIssued	87394512	shares
CY2014Q3	us-gaap	Common Stock Shares Issued CommonStockSharesIssued	87711731	shares
CY2014Q3	us-gaap	Common Stock Shares Outstanding CommonStockSharesOutstanding	87711731	shares
CY2013Q4	us-gaap	Common Stock Shares Outstanding CommonStockSharesOutstanding	87394512	shares
CY2012Q4	us-gaap	Common Stock Shares Outstanding CommonStockSharesOutstanding	80952986	shares
CY2013Q3	us-gaap	Common Stock Shares Outstanding CommonStockSharesOutstanding	87381395	shares
CY2013Q4	us-gaap	Common Stock Value CommonStockValue	874000	USD
CY2014Q3	us-gaap	Common Stock Value CommonStockValue	877000	USD
	us-gaap	Comparability Of Prior Year Financial Data ComparabilityOfPriorYearFinancialData	<div style="font-family:Times New Roman;font-size:10pt;"><div style="line-height:120%;text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;font-weight:bold;">Prior Out of Period Adjustment</font></div><div style="line-height:120%;text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"><br clear="none"/></font></div><div style="line-height:120%;text-align:left;text-indent:24px;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">As previously disclosed in our 2013 Annual Report on Form 10-K, during the second quarter of 2013, we identified an error related to the estimated fair value of a redeemable noncontrolling interest in a real estate joint venture. Changes in such fair value are reported as changes in equity with no impact to net income or comprehensive income. The error resulted in an understatement of the line entitled “redeemable noncontrolling interest” in the mezzanine section of our consolidated balance sheet and an overstatement of the line entitled “additional paid-in capital” in the equity section of our consolidation balance sheet of </font><font style="font-family:Times New Roman;font-size:10pt;color:#000000;font-style:normal;font-weight:normal;text-decoration:none;">$3.7 million</font><font style="font-family:inherit;font-size:10pt;"> as of December 31, 2012. We have determined that this adjustment was not material to our financial statements for 2012 or 2013. Accordingly, this change is reported as an out-of-period adjustment in the nine months ended September 30, 2013. </font></div></div>
CY2014Q3	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	24351000	USD
	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	32741000	USD
	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	15051000	USD
CY2013Q3	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	-3671000	USD
CY2013Q3	us-gaap	Comprehensive Income Net Of Tax Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxAttributableToNoncontrollingInterest	948000	USD
	us-gaap	Comprehensive Income Net Of Tax Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxAttributableToNoncontrollingInterest	3960000	USD
CY2014Q3	us-gaap	Comprehensive Income Net Of Tax Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxAttributableToNoncontrollingInterest	1968000	USD
	us-gaap	Comprehensive Income Net Of Tax Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxAttributableToNoncontrollingInterest	2722000	USD
CY2013Q3	us-gaap	Comprehensive Income Net Of Tax Including Portion Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest	-2723000	USD
	us-gaap	Comprehensive Income Net Of Tax Including Portion Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest	36701000	USD
CY2014Q3	us-gaap	Comprehensive Income Net Of Tax Including Portion Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest	26319000	USD
	us-gaap	Comprehensive Income Net Of Tax Including Portion Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest	17773000	USD
CY2013Q3	us-gaap	Contracts Revenue ContractsRevenue	16991000	USD
	us-gaap	Contracts Revenue ContractsRevenue	80390000	USD
	us-gaap	Contracts Revenue ContractsRevenue	52048000	USD
CY2014Q3	us-gaap	Contracts Revenue ContractsRevenue	34739000	USD
CY2013Q3	us-gaap	Cost Of Services CostOfServices	16306000	USD
CY2014Q3	us-gaap	Cost Of Services CostOfServices	33593000	USD
	us-gaap	Cost Of Services CostOfServices	75353000	USD
	us-gaap	Cost Of Services CostOfServices	49165000	USD
CY2013Q3	us-gaap	Costs And Expenses CostsAndExpenses	101139000	USD
CY2013Q4	us-gaap	Deferred Costs Current And Noncurrent DeferredCostsCurrentAndNoncurrent	66267000	USD
CY2014Q3	us-gaap	Deferred Costs Current And Noncurrent DeferredCostsCurrentAndNoncurrent	65009000	USD
CY2014Q3	us-gaap	Costs In Excess Of Billings On Uncompleted Contracts Or Programs CostsInExcessOfBillingsOnUncompletedContractsOrPrograms	17962000	USD
CY2013Q4	us-gaap	Costs In Excess Of Billings On Uncompleted Contracts Or Programs CostsInExcessOfBillingsOnUncompletedContractsOrPrograms	2462000	USD
CY2013Q4	us-gaap	Deferred Rent Receivables Net DeferredRentReceivablesNet	89456000	USD
CY2014Q3	us-gaap	Deferred Rent Receivables Net DeferredRentReceivablesNet	95405000	USD
CY2014Q3	us-gaap	Deferred Revenue Leases Net DeferredRevenueLeasesNet	13420000	USD
CY2013Q4	us-gaap	Deferred Revenue Leases Net DeferredRevenueLeasesNet	10369000	USD
CY2013Q4	us-gaap	Deferred Tax Assets Net DeferredTaxAssetsNet	4305000	USD
CY2014Q3	us-gaap	Deferred Tax Assets Net DeferredTaxAssetsNet	4058000	USD
	us-gaap	Depreciation And Amortization DepreciationAndAmortization	104728000	USD
CY2014Q3	us-gaap	Depreciation And Amortization DepreciationAndAmortization	30237000	USD
CY2013Q3	us-gaap	Depreciation And Amortization DepreciationAndAmortization	28205000	USD
	us-gaap	Depreciation And Amortization DepreciationAndAmortization	82888000	USD
	us-gaap	Depreciation Depletion And Amortization DepreciationDepletionAndAmortization	106619000	USD
	us-gaap	Depreciation Depletion And Amortization DepreciationDepletionAndAmortization	87956000	USD
CY2013Q4	us-gaap	Development In Process DevelopmentInProcess	511608000	USD
CY2014Q3	us-gaap	Development In Process DevelopmentInProcess	513949000	USD
	us-gaap	Direct Costs Of Leased And Rented Property Or Equipment DirectCostsOfLeasedAndRentedPropertyOrEquipment	123082000	USD
CY2013Q3	us-gaap	Direct Costs Of Leased And Rented Property Or Equipment DirectCostsOfLeasedAndRentedPropertyOrEquipment	41361000	USD
	us-gaap	Direct Costs Of Leased And Rented Property Or Equipment DirectCostsOfLeasedAndRentedPropertyOrEquipment	136600000	USD
CY2014Q3	us-gaap	Direct Costs Of Leased And Rented Property Or Equipment DirectCostsOfLeasedAndRentedPropertyOrEquipment	43056000	USD
	us-gaap	Disposal Group Including Discontinued Operation Interest Expense DisposalGroupIncludingDiscontinuedOperationInterestExpense	0	USD
CY2013Q3	us-gaap	Disposal Group Including Discontinued Operation Interest Expense DisposalGroupIncludingDiscontinuedOperationInterestExpense	1968000	USD
	us-gaap	Disposal Group Including Discontinued Operation Interest Expense DisposalGroupIncludingDiscontinuedOperationInterestExpense	6316000	USD
CY2014Q3	us-gaap	Disposal Group Including Discontinued Operation Interest Expense DisposalGroupIncludingDiscontinuedOperationInterestExpense	0	USD
	us-gaap	Disposal Group Including Discontinued Operation Revenue DisposalGroupIncludingDiscontinuedOperationRevenue	29403000	USD
	us-gaap	Disposal Group Including Discontinued Operation Revenue DisposalGroupIncludingDiscontinuedOperationRevenue	-12000	USD
CY2013Q3	us-gaap	Disposal Group Including Discontinued Operation Revenue DisposalGroupIncludingDiscontinuedOperationRevenue	9740000	USD
CY2014Q3	us-gaap	Disposal Group Including Discontinued Operation Revenue DisposalGroupIncludingDiscontinuedOperationRevenue	-36000	USD
	us-gaap	Dividends Dividends	84692000	USD
	us-gaap	Dividends Dividends	86700000	USD
CY2013Q4	us-gaap	Dividends Payable Current And Noncurrent DividendsPayableCurrentAndNoncurrent	29080000	USD
CY2014Q3	us-gaap	Dividends Payable Current And Noncurrent DividendsPayableCurrentAndNoncurrent	28344000	USD
CY2013Q3	us-gaap	Dividends Payable Current And Noncurrent DividendsPayableCurrentAndNoncurrent	29077000	USD
CY2014Q3	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.22
	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	-0.14
	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.24
CY2013Q3	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	-0.09
	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	-0.14
CY2013Q3	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	-0.09
	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.24
CY2014Q3	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.22
CY2013Q4	us-gaap	Equity Method Investments EquityMethodInvestments	2258000	USD
CY2014Q3	us-gaap	Equity Method Investments EquityMethodInvestments	2240000	USD
	us-gaap	Income Loss From Continuing Operations Attributable To Noncontrolling Entity IncomeLossFromContinuingOperationsAttributableToNoncontrollingEntity	3923000	USD
	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	28686000	USD
	us-gaap	Gain Loss On Sale Of Properties GainLossOnSaleOfProperties	10654000	USD
	us-gaap	Gain Loss On Sale Of Properties GainLossOnSaleOfProperties	2683000	USD
CY2014Q3	us-gaap	Gain Loss On Sale Of Properties Net Of Applicable Income Taxes GainLossOnSaleOfPropertiesNetOfApplicableIncomeTaxes	10630000	USD
	us-gaap	Gain Loss On Sale Of Properties Net Of Applicable Income Taxes GainLossOnSaleOfPropertiesNetOfApplicableIncomeTaxes	10630000	USD
CY2013Q3	us-gaap	Gain Loss On Sale Of Properties Net Of Applicable Income Taxes GainLossOnSaleOfPropertiesNetOfApplicableIncomeTaxes	0	USD
	us-gaap	Gain Loss On Sale Of Properties Net Of Applicable Income Taxes GainLossOnSaleOfPropertiesNetOfApplicableIncomeTaxes	2683000	USD
CY2014Q3	us-gaap	Gains Losses On Extinguishment Of Debt GainsLossesOnExtinguishmentOfDebt	-176000	USD
	us-gaap	Gains Losses On Extinguishment Of Debt GainsLossesOnExtinguishmentOfDebt	-446000	USD
	us-gaap	Gains Losses On Extinguishment Of Debt GainsLossesOnExtinguishmentOfDebt	-27028000	USD
CY2013Q3	us-gaap	Gains Losses On Extinguishment Of Debt GainsLossesOnExtinguishmentOfDebt	-374000	USD
CY2014Q3	us-gaap	Guarantee Obligations Current Carrying Value GuaranteeObligationsCurrentCarryingValue	1100000	USD
	us-gaap	Impairment Of Real Estate ImpairmentOfRealEstate	30940000	USD
	us-gaap	Impairment Of Real Estate ImpairmentOfRealEstate	1371000	USD
CY2013Q4	us-gaap	Incentive To Lessee IncentiveToLessee	8435000	USD
CY2014Q3	us-gaap	Incentive To Lessee IncentiveToLessee	12939000	USD
	us-gaap	Income Loss Before Gain Or Loss On Sale Of Properties Extraordinary Items And Cumulative Effects Of Accounting Changes IncomeLossBeforeGainOrLossOnSaleOfPropertiesExtraordinaryItemsAndCumulativeEffectsOfAccountingChanges	6189000	USD
CY2013Q3	us-gaap	Income Loss Before Gain Or Loss On Sale Of Properties Extraordinary Items And Cumulative Effects Of Accounting Changes IncomeLossBeforeGainOrLossOnSaleOfPropertiesExtraordinaryItemsAndCumulativeEffectsOfAccountingChanges	-2000000	USD
CY2014Q3	us-gaap	Income Loss Before Gain Or Loss On Sale Of Properties Extraordinary Items And Cumulative Effects Of Accounting Changes IncomeLossBeforeGainOrLossOnSaleOfPropertiesExtraordinaryItemsAndCumulativeEffectsOfAccountingChanges	13918000	USD
	us-gaap	Income Loss Before Gain Or Loss On Sale Of Properties Extraordinary Items And Cumulative Effects Of Accounting Changes IncomeLossBeforeGainOrLossOnSaleOfPropertiesExtraordinaryItemsAndCumulativeEffectsOfAccountingChanges	28639000	USD
	us-gaap	Income Loss From Continuing Operations IncomeLossFromContinuingOperations	35342000	USD
	us-gaap	Income Loss From Continuing Operations IncomeLossFromContinuingOperations	22377000	USD
CY2013Q3	us-gaap	Income Loss From Continuing Operations IncomeLossFromContinuingOperations	9518000	USD
CY2014Q3	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	13635000	USD
CY2014Q3	us-gaap	Income Loss From Continuing Operations IncomeLossFromContinuingOperations	22537000	USD
CY2013Q3	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	24000	USD
CY2014Q3	us-gaap	Income Loss From Continuing Operations Attributable To Noncontrolling Entity IncomeLossFromContinuingOperationsAttributableToNoncontrollingEntity	1820000	USD
CY2013Q3	us-gaap	Income Loss From Continuing Operations Attributable To Noncontrolling Entity IncomeLossFromContinuingOperationsAttributableToNoncontrollingEntity	1456000	USD
	us-gaap	Income Loss From Continuing Operations Attributable To Noncontrolling Entity IncomeLossFromContinuingOperationsAttributableToNoncontrollingEntity	2710000	USD
	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	22254000	USD
CY2013Q3	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	10954000	USD
	us-gaap	Income Loss From Continuing Operations Including Portion Attributable To Noncontrolling Interest IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest	22404000	USD
CY2013Q3	us-gaap	Income Loss From Continuing Operations Including Portion Attributable To Noncontrolling Interest IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest	10974000	USD
	us-gaap	Income Loss From Continuing Operations Including Portion Attributable To Noncontrolling Interest IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest	28635000	USD
CY2014Q3	us-gaap	Income Loss From Continuing Operations Including Portion Attributable To Noncontrolling Interest IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest	13727000	USD
CY2014Q3	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	0.22
CY2013Q3	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	0.06
	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	0.04
	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	0.24
CY2014Q3	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	0.22
CY2013Q3	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	0.06
	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	0.24
	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	0.04
	us-gaap	Income Loss From Discontinued Operations Net Of Tax IncomeLossFromDiscontinuedOperationsNetOfTax	4000	USD
	us-gaap	Income Loss From Discontinued Operations Net Of Tax IncomeLossFromDiscontinuedOperationsNetOfTax	-16215000	USD
CY2014Q3	us-gaap	Income Loss From Discontinued Operations Net Of Tax IncomeLossFromDiscontinuedOperationsNetOfTax	191000	USD
CY2013Q3	us-gaap	Income Loss From Discontinued Operations Net Of Tax IncomeLossFromDiscontinuedOperationsNetOfTax	-12974000	USD
CY2014Q3	us-gaap	Income Loss From Discontinued Operations Net Of Tax Attributable To Noncontrolling Interest IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToNoncontrollingInterest	8000	USD
	us-gaap	Income Loss From Discontinued Operations Net Of Tax Attributable To Noncontrolling Interest IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToNoncontrollingInterest	-529000	USD
CY2013Q3	us-gaap	Income Loss From Discontinued Operations Net Of Tax Attributable To Noncontrolling Interest IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToNoncontrollingInterest	-492000	USD
	us-gaap	Income Loss From Discontinued Operations Net Of Tax Attributable To Noncontrolling Interest IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToNoncontrollingInterest	-5000	USD
CY2013Q3	us-gaap	Income Loss From Discontinued Operations Net Of Tax Attributable To Reporting Entity IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity	-12482000	USD
	us-gaap	Income Loss From Discontinued Operations Net Of Tax Attributable To Reporting Entity IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity	9000	USD
CY2014Q3	us-gaap	Income Loss From Discontinued Operations Net Of Tax Attributable To Reporting Entity IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity	183000	USD
	us-gaap	Income Loss From Discontinued Operations Net Of Tax Attributable To Reporting Entity IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity	-15686000	USD
	us-gaap	Income Loss From Discontinued Operations Net Of Tax Per Basic Share IncomeLossFromDiscontinuedOperationsNetOfTaxPerBasicShare	0.00
	us-gaap	Income Loss From Discontinued Operations Net Of Tax Per Basic Share IncomeLossFromDiscontinuedOperationsNetOfTaxPerBasicShare	-0.18
CY2013Q3	us-gaap	Income Loss From Discontinued Operations Net Of Tax Per Basic Share IncomeLossFromDiscontinuedOperationsNetOfTaxPerBasicShare	-0.15
CY2014Q3	us-gaap	Income Loss From Discontinued Operations Net Of Tax Per Basic Share IncomeLossFromDiscontinuedOperationsNetOfTaxPerBasicShare	0.00
	us-gaap	Income Loss From Discontinued Operations Net Of Tax Per Diluted Share IncomeLossFromDiscontinuedOperationsNetOfTaxPerDilutedShare	0.00
	us-gaap	Income Loss From Discontinued Operations Net Of Tax Per Diluted Share IncomeLossFromDiscontinuedOperationsNetOfTaxPerDilutedShare	-0.18
CY2014Q3	us-gaap	Income Loss From Discontinued Operations Net Of Tax Per Diluted Share IncomeLossFromDiscontinuedOperationsNetOfTaxPerDilutedShare	0.00
CY2013Q3	us-gaap	Income Loss From Discontinued Operations Net Of Tax Per Diluted Share IncomeLossFromDiscontinuedOperationsNetOfTaxPerDilutedShare	-0.15
	us-gaap	Income Loss From Equity Method Investments IncomeLossFromEquityMethodInvestments	211000	USD
	us-gaap	Income Loss From Equity Method Investments IncomeLossFromEquityMethodInvestments	206000	USD
CY2014Q3	us-gaap	Income Loss From Equity Method Investments IncomeLossFromEquityMethodInvestments	193000	USD
CY2013Q3	us-gaap	Income Loss From Equity Method Investments IncomeLossFromEquityMethodInvestments	44000	USD
	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	257000	USD
CY2014Q3	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	101000	USD
	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	61000	USD
	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	0	shares
	us-gaap	Income Taxes Paid Net IncomeTaxesPaidNet	-6000	USD
	us-gaap	Income Taxes Paid Net IncomeTaxesPaidNet	-200000	USD
CY2013Q4	us-gaap	Minority Interest In Operating Partnerships MinorityInterestInOperatingPartnerships	53468000	USD
CY2014Q3	us-gaap	Minority Interest In Preferred Unit Holders MinorityInterestInPreferredUnitHolders	8800000	USD
	us-gaap	Increase Decrease In Accounts Receivable IncreaseDecreaseInAccountsReceivable	-1523000	USD
	us-gaap	Increase Decrease In Accounts Receivable IncreaseDecreaseInAccountsReceivable	-6815000	USD
	us-gaap	Increase Decrease In Operating Liabilities IncreaseDecreaseInOperatingLiabilities	18000	USD
	us-gaap	Increase Decrease In Operating Liabilities IncreaseDecreaseInOperatingLiabilities	24247000	USD
	us-gaap	Increase Decrease In Prepaid Deferred Expense And Other Assets IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets	12974000	USD
	us-gaap	Increase Decrease In Prepaid Deferred Expense And Other Assets IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets	26553000	USD
CY2014Q3	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	195000	shares
CY2013Q3	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	0	shares
CY2014Q3	us-gaap	Intangible Assets Net Excluding Goodwill IntangibleAssetsNetExcludingGoodwill	48300000	USD
CY2013Q4	us-gaap	Intangible Assets Net Excluding Goodwill IntangibleAssetsNetExcludingGoodwill	59258000	USD
CY2014Q3	us-gaap	Interest And Debt Expense InterestAndDebtExpense	24802000	USD
CY2013Q3	us-gaap	Interest And Debt Expense InterestAndDebtExpense	19342000	USD
	us-gaap	Interest And Debt Expense InterestAndDebtExpense	60734000	USD
	us-gaap	Interest And Debt Expense InterestAndDebtExpense	69107000	USD
	us-gaap	Interest Costs Capitalized InterestCostsCapitalized	6700000	USD
CY2013Q3	us-gaap	Interest Costs Capitalized InterestCostsCapitalized	2200000	USD
	us-gaap	Interest Costs Capitalized InterestCostsCapitalized	4300000	USD
CY2014Q3	us-gaap	Interest Costs Capitalized InterestCostsCapitalized	1300000	USD
	us-gaap	Interest Paid Net InterestPaidNet	59052000	USD
	us-gaap	Interest Paid Net InterestPaidNet	54683000	USD
CY2013Q4	us-gaap	Interest Rate Cash Flow Hedge Asset At Fair Value InterestRateCashFlowHedgeAssetAtFairValue	6594000	USD
CY2014Q3	us-gaap	Interest Rate Cash Flow Hedge Asset At Fair Value InterestRateCashFlowHedgeAssetAtFairValue	2907000	USD
CY2013Q4	us-gaap	Interest Rate Derivative Liabilities At Fair Value InterestRateDerivativeLiabilitiesAtFairValue	3309000	USD
CY2014Q3	us-gaap	Interest Rate Derivative Liabilities At Fair Value InterestRateDerivativeLiabilitiesAtFairValue	2236000	USD
CY2013Q4	us-gaap	Liabilities Liabilities	2114945000	USD
CY2014Q3	us-gaap	Liabilities Liabilities	2264248000	USD
CY2013Q4	us-gaap	Liabilities And Stockholders Equity LiabilitiesAndStockholdersEquity	3629952000	USD
CY2014Q3	us-gaap	Liabilities And Stockholders Equity LiabilitiesAndStockholdersEquity	3680188000	USD
CY2014Q3	us-gaap	Long Term Debt LongTermDebt	2049992000	USD
CY2013Q4	us-gaap	Long Term Debt LongTermDebt	1927703000	USD
CY2013Q4	us-gaap	Minority Interest MinorityInterest	71665000	USD
CY2014Q3	us-gaap	Minority Interest MinorityInterest	67368000	USD
	us-gaap	Minority Interest Change In Redemption Value MinorityInterestChangeInRedemptionValue	6414000	USD
	us-gaap	Minority Interest Change In Redemption Value MinorityInterestChangeInRedemptionValue	7000	USD
CY2014Q3	us-gaap	Minority Interest In Operating Partnerships MinorityInterestInOperatingPartnerships	49781000	USD
CY2013Q4	us-gaap	Minority Interest In Preferred Unit Holders MinorityInterestInPreferredUnitHolders	8800000	USD
	us-gaap	Nature Of Operations NatureOfOperations	<div style="font-family:Times New Roman;font-size:10pt;"><div style="line-height:120%;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;font-weight:bold;">Organization</font></div><div style="line-height:120%;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"> </font></div><div style="line-height:120%;text-indent:24px;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">Corporate Office Properties Trust (“COPT”) and subsidiaries (collectively, the “Company”) is a fully-integrated and self-managed real estate investment trust (“REIT”). Corporate Office Properties, L.P. (“COPLP”) and subsidiaries (collectively, the “Operating Partnership”) is the entity through which COPT, the sole general partner of COPLP, conducts almost all of its operations and owns almost all of its assets. Unless otherwise expressly stated or the context otherwise requires, “we”, “us” and “our” as used herein refer to each of the Company and the Operating Partnership. We focus primarily on serving the specialized requirements of United States Government agencies and defense contractors, most of whom are engaged in defense information technology and national security related activities. We generally acquire, develop, manage and lease office and data center properties concentrated in large office parks located near knowledge-based government demand drivers and/or in targeted markets or submarkets in the Greater Washington, DC/Baltimore region. As of </font><font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;">September 30, 2014</font><font style="font-family:inherit;font-size:10pt;">, our properties included the following:</font></div><div style="line-height:120%;padding-left:24px;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"><br clear="none"/></font></div><table cellpadding="0" cellspacing="0" style="font-family:Times New Roman; font-size:10pt;"><tr><td style="width:24px;" rowspan="1" colspan="1"></td><td rowspan="1" colspan="1"></td></tr><tr><td style="vertical-align:top" rowspan="1" colspan="1"><div style="line-height:120%;font-size:10pt;padding-left:0px;"><font style="font-family:inherit;font-size:10pt;">•</font></div></td><td style="vertical-align:top;" rowspan="1" colspan="1"><div style="line-height:120%;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;">174</font><font style="font-family:inherit;font-size:10pt;"> operating office properties totaling </font><font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;">16.9 million</font><font style="font-family:inherit;font-size:10pt;"> square feet (excluding </font><font style="font-family:inherit;font-size:10pt;">two</font><font style="font-family:inherit;font-size:10pt;"> properties serving as collateral for a nonrecourse mortgage loan which is in default, as discussed further in the Management’s Discussion and Analysis of Financial Condition and Results of Operations section of this Quarterly Report on Form 10-Q);</font></div></td></tr></table><table cellpadding="0" cellspacing="0" style="font-family:Times New Roman; font-size:10pt;"><tr><td style="width:24px;" rowspan="1" colspan="1"></td><td rowspan="1" colspan="1"></td></tr><tr><td style="vertical-align:top" rowspan="1" colspan="1"><div style="line-height:120%;font-size:10pt;padding-left:0px;"><font style="font-family:inherit;font-size:10pt;">•</font></div></td><td style="vertical-align:top;" rowspan="1" colspan="1"><div style="line-height:120%;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;">10</font><font style="font-family:inherit;font-size:10pt;"> office properties under, or contractually committed for, construction or redevelopment that we estimate will total approximately </font><font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;">1.1 million</font><font style="font-family:inherit;font-size:10pt;"> square feet upon completion;</font></div></td></tr></table><table cellpadding="0" cellspacing="0" style="font-family:Times New Roman; font-size:10pt;"><tr><td style="width:24px;" rowspan="1" colspan="1"></td><td rowspan="1" colspan="1"></td></tr><tr><td style="vertical-align:top" rowspan="1" colspan="1"><div style="line-height:120%;font-size:10pt;padding-left:0px;"><font style="font-family:inherit;font-size:10pt;">•</font></div></td><td style="vertical-align:top;" rowspan="1" colspan="1"><div style="line-height:120%;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;">1,480</font><font style="font-family:inherit;font-size:10pt;"> acres of land we control that we believe are potentially developable into approximately </font><font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;">18.7 million</font><font style="font-family:inherit;font-size:10pt;"> square feet; and</font></div></td></tr></table><table cellpadding="0" cellspacing="0" style="font-family:Times New Roman; font-size:10pt;"><tr><td style="width:24px;" rowspan="1" colspan="1"></td><td rowspan="1" colspan="1"></td></tr><tr><td style="vertical-align:top" rowspan="1" colspan="1"><div style="line-height:120%;font-size:10pt;padding-left:0px;"><font style="font-family:inherit;font-size:10pt;">•</font></div></td><td style="vertical-align:top;" rowspan="1" colspan="1"><div style="line-height:120%;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">a partially operational, wholesale data center which upon completion and stabilization is expected to have a critical load of </font><font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;">18</font><font style="font-family:inherit;font-size:10pt;"> megawatts.</font></div></td></tr></table><div style="line-height:120%;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"> </font></div><div style="line-height:120%;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">COPLP owns real estate both directly and through subsidiary partnerships and limited liability companies (“LLCs”).  In addition to owning real estate, COPLP also owns subsidiaries that provide real estate services such as property management and construction and development services primarily for our properties but also for third parties. Some of these services are performed by a taxable REIT subsidiary (“TRS”).</font></div><div style="line-height:120%;text-indent:24px;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"><br clear="none"/></font></div><div style="line-height:120%;text-indent:24px;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">Interests in COPLP are in the form of common and preferred units. As of </font><font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;">September 30, 2014</font><font style="font-family:inherit;font-size:10pt;">, COPT owned </font><font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;">95.8%</font><font style="font-family:inherit;font-size:10pt;"> of the outstanding COPLP common units (“common units”) and </font><font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;">95.5%</font><font style="font-family:inherit;font-size:10pt;"> of the outstanding COPLP preferred units (“preferred units”); the remaining common and preferred units in COPLP were owned by third parties. Common units in COPLP not owned by COPT carry certain redemption rights. The number of common units in COPLP owned by COPT is equivalent to the number of outstanding common shares of beneficial interest (“common shares”) of COPT, and the entitlement of all COPLP common units to quarterly distributions and payments in liquidation are substantially the same as those of COPT common shareholders. Similarly, in the case of each series of preferred units in COPLP held by COPT, there is a series of preferred shares of beneficial interest (“preferred shares”) in COPT that is equivalent in number and carries substantially the same terms as such series of COPLP preferred units. COPT’s common shares are publicly traded on the New York Stock Exchange (“NYSE”) under the ticker symbol “OFC”. </font></div><div style="line-height:120%;text-indent:24px;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"><br clear="none"/></font></div><div style="line-height:120%;text-indent:24px;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">Because COPLP is managed by COPT, and COPT conducts substantially all of its operations through COPLP, we refer to COPT’s executive officers as COPLP’s executive officers, and although, as a partnership, COPLP does not have a board of trustees, we refer to COPT’s Board of Trustees as COPLP’s Board of Trustees.</font></div></div>
	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	96560000	USD
	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	-21557000	USD
	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-186845000	USD
	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-137046000	USD
	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	144248000	USD
	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	107009000	USD
	us-gaap	Net Income Loss NetIncomeLoss	35351000	USD
CY2014Q3	us-gaap	Net Income Loss NetIncomeLoss	22720000	USD
CY2013Q3	us-gaap	Net Income Loss NetIncomeLoss	-2964000	USD
	us-gaap	Net Income Loss NetIncomeLoss	6691000	USD
	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	-11694000	USD
CY2014Q3	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	19167000	USD
CY2013Q3	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	-7454000	USD
	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	21195000	USD
CY2013Q3	us-gaap	Noncontrolling Interest In Net Income Loss Operating Partnerships Nonredeemable NoncontrollingInterestInNetIncomeLossOperatingPartnershipsNonredeemable	-232000	USD
	us-gaap	Noncontrolling Interest In Net Income Loss Operating Partnerships Nonredeemable NoncontrollingInterestInNetIncomeLossOperatingPartnershipsNonredeemable	942000	USD
	us-gaap	Noncontrolling Interest In Net Income Loss Operating Partnerships Nonredeemable NoncontrollingInterestInNetIncomeLossOperatingPartnershipsNonredeemable	-474000	USD
CY2014Q3	us-gaap	Noncontrolling Interest In Net Income Loss Operating Partnerships Nonredeemable NoncontrollingInterestInNetIncomeLossOperatingPartnershipsNonredeemable	768000	USD
CY2013Q3	us-gaap	Noncontrolling Interest In Net Income Loss Preferred Unit Holders Nonredeemable NoncontrollingInterestInNetIncomeLossPreferredUnitHoldersNonredeemable	165000	USD
	us-gaap	Noncontrolling Interest In Net Income Loss Preferred Unit Holders Nonredeemable NoncontrollingInterestInNetIncomeLossPreferredUnitHoldersNonredeemable	495000	USD
CY2014Q3	us-gaap	Noncontrolling Interest In Net Income Loss Preferred Unit Holders Nonredeemable NoncontrollingInterestInNetIncomeLossPreferredUnitHoldersNonredeemable	165000	USD
	us-gaap	Noncontrolling Interest In Net Income Loss Preferred Unit Holders Nonredeemable NoncontrollingInterestInNetIncomeLossPreferredUnitHoldersNonredeemable	495000	USD
	us-gaap	Noncontrolling Interest Increase From Subsidiary Equity Issuance NoncontrollingInterestIncreaseFromSubsidiaryEquityIssuance	0	USD
	us-gaap	Noncontrolling Interest Increase From Subsidiary Equity Issuance NoncontrollingInterestIncreaseFromSubsidiaryEquityIssuance	0	USD
CY2013Q4	us-gaap	Notes Receivable Net NotesReceivableNet	53663000	USD
CY2014Q3	us-gaap	Notes Receivable Net NotesReceivableNet	50886000	USD
CY2014Q3	us-gaap	Operating Income Loss OperatingIncomeLoss	37422000	USD
	us-gaap	Operating Income Loss OperatingIncomeLoss	94464000	USD
CY2013Q3	us-gaap	Operating Income Loss OperatingIncomeLoss	30673000	USD
	us-gaap	Operating Income Loss OperatingIncomeLoss	107067000	USD
	us-gaap	Operating Leases Income Statement Lease Revenue OperatingLeasesIncomeStatementLeaseRevenue	288574000	USD
CY2014Q3	us-gaap	Operating Leases Income Statement Lease Revenue OperatingLeasesIncomeStatementLeaseRevenue	96207000	USD
	us-gaap	Operating Leases Income Statement Lease Revenue OperatingLeasesIncomeStatementLeaseRevenue	280911000	USD
CY2013Q3	us-gaap	Operating Leases Income Statement Lease Revenue OperatingLeasesIncomeStatementLeaseRevenue	94641000	USD
CY2013Q4	us-gaap	Other Assets OtherAssets	4268000	USD
CY2014Q3	us-gaap	Other Assets OtherAssets	3733000	USD
CY2013Q3	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Net Of Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax	1070000	USD
CY2014Q3	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Net Of Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax	0	USD
	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Net Of Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax	1070000	USD
	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Net Of Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax	0	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	-2568000	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	8901000	USD
CY2013Q3	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	-723000	USD
CY2014Q3	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	1771000	USD
CY2014Q3	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci On Derivatives Net Of Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIOnDerivativesNetOfTax	-756000	USD
	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci On Derivatives Net Of Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIOnDerivativesNetOfTax	-2170000	USD
	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci On Derivatives Net Of Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIOnDerivativesNetOfTax	-2021000	USD
CY2013Q3	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci On Derivatives Net Of Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIOnDerivativesNetOfTax	-689000	USD
	us-gaap	Other Comprehensive Income Unrealized Gain Loss On Derivatives Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodNetOfTax	-4738000	USD
	us-gaap	Other Comprehensive Income Unrealized Gain Loss On Derivatives Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodNetOfTax	5810000	USD
CY2013Q3	us-gaap	Other Comprehensive Income Unrealized Gain Loss On Derivatives Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodNetOfTax	-2482000	USD
CY2014Q3	us-gaap	Other Comprehensive Income Unrealized Gain Loss On Derivatives Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodNetOfTax	1015000	USD
CY2014Q3	us-gaap	Other Liabilities OtherLiabilities	13288000	USD
CY2013Q4	us-gaap	Other Liabilities OtherLiabilities	14207000	USD
	us-gaap	Other Noncash Income Expense OtherNoncashIncomeExpense	2446000	USD
	us-gaap	Other Noncash Income Expense OtherNoncashIncomeExpense	2284000	USD
	us-gaap	Other Nonoperating Income OtherNonoperatingIncome	3775000	USD
CY2014Q3	us-gaap	Other Nonoperating Income OtherNonoperatingIncome	1191000	USD
	us-gaap	Other Nonoperating Income OtherNonoperatingIncome	2949000	USD
CY2013Q3	us-gaap	Other Nonoperating Income OtherNonoperatingIncome	-3000	USD
CY2013Q3	us-gaap	Other Preferred Stock Dividends And Adjustments OtherPreferredStockDividendsAndAdjustments	0	USD
	us-gaap	Other Preferred Stock Dividends And Adjustments OtherPreferredStockDividendsAndAdjustments	1769000	USD
	us-gaap	Other Preferred Stock Dividends And Adjustments OtherPreferredStockDividendsAndAdjustments	2904000	USD
CY2014Q3	us-gaap	Other Preferred Stock Dividends And Adjustments OtherPreferredStockDividendsAndAdjustments	0	USD
	us-gaap	Other Real Estate Revenue OtherRealEstateRevenue	61599000	USD
	us-gaap	Other Real Estate Revenue OtherRealEstateRevenue	70538000	USD
CY2014Q3	us-gaap	Other Real Estate Revenue OtherRealEstateRevenue	22069000	USD
CY2013Q3	us-gaap	Other Real Estate Revenue OtherRealEstateRevenue	20180000	USD
	us-gaap	Payments For Capital Improvements PaymentsForCapitalImprovements	17528000	USD
	us-gaap	Payments For Capital Improvements PaymentsForCapitalImprovements	21179000	USD
	us-gaap	Payments For Leasing Costs PaymentsForLeasingCosts	10549000	USD
	us-gaap	Payments For Leasing Costs PaymentsForLeasingCosts	9366000	USD
	us-gaap	Payments For Proceeds From Other Investing Activities PaymentsForProceedsFromOtherInvestingActivities	-4257000	USD
	us-gaap	Payments For Proceeds From Other Investing Activities PaymentsForProceedsFromOtherInvestingActivities	1343000	USD
	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	1848000	USD
	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	1389000	USD
	us-gaap	Payments For Repurchase Of Redeemable Preferred Stock PaymentsForRepurchaseOfRedeemablePreferredStock	50000000	USD
	us-gaap	Payments For Repurchase Of Redeemable Preferred Stock PaymentsForRepurchaseOfRedeemablePreferredStock	84750000	USD
	us-gaap	Payments For Tenant Improvements PaymentsForTenantImprovements	15868000	USD
	us-gaap	Payments For Tenant Improvements PaymentsForTenantImprovements	17754000	USD
	us-gaap	Payments Of Debt Extinguishment Costs PaymentsOfDebtExtinguishmentCosts	104000	USD
	us-gaap	Payments Of Debt Extinguishment Costs PaymentsOfDebtExtinguishmentCosts	23969000	USD
	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	72217000	USD
	us-gaap	Payments To Develop Real Estate Assets PaymentsToDevelopRealEstateAssets	150862000	USD
	us-gaap	Payments To Develop Real Estate Assets PaymentsToDevelopRealEstateAssets	156820000	USD
	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	69451000	USD
	us-gaap	Payments Of Dividends Minority Interest PaymentsOfDividendsMinorityInterest	3786000	USD
	us-gaap	Proceeds From Sale Of Real Estate Heldforinvestment ProceedsFromSaleOfRealEstateHeldforinvestment	12447000	USD
	us-gaap	Payments Of Dividends Preferred Stock And Preference Stock PaymentsOfDividendsPreferredStockAndPreferenceStock	16845000	USD
	us-gaap	Payments Of Dividends Preferred Stock And Preference Stock PaymentsOfDividendsPreferredStockAndPreferenceStock	13179000	USD
	us-gaap	Payments Of Financing Costs PaymentsOfFinancingCosts	694000	USD
	us-gaap	Payments Of Financing Costs PaymentsOfFinancingCosts	9001000	USD
	us-gaap	Payments To Acquire Notes Receivable PaymentsToAcquireNotesReceivable	4111000	USD
	us-gaap	Payments To Acquire Notes Receivable PaymentsToAcquireNotesReceivable	3610000	USD
CY2013Q3	us-gaap	Preferred Stock Dividends Income Statement Impact PreferredStockDividendsIncomeStatementImpact	4490000	USD
	us-gaap	Preferred Stock Dividends Income Statement Impact PreferredStockDividendsIncomeStatementImpact	12387000	USD
	us-gaap	Preferred Stock Dividends Income Statement Impact PreferredStockDividendsIncomeStatementImpact	15481000	USD
CY2014Q3	us-gaap	Preferred Stock Dividends Income Statement Impact PreferredStockDividendsIncomeStatementImpact	3553000	USD
CY2013Q4	us-gaap	Preferred Stock Liquidation Preference Value PreferredStockLiquidationPreferenceValue	249083000	USD
CY2014Q3	us-gaap	Preferred Stock Liquidation Preference Value PreferredStockLiquidationPreferenceValue	199083000	USD
CY2014Q3	us-gaap	Preferred Stock Par Or Stated Value Per Share PreferredStockParOrStatedValuePerShare	0.01
CY2013Q4	us-gaap	Preferred Stock Par Or Stated Value Per Share PreferredStockParOrStatedValuePerShare	0.01
CY2014Q3	us-gaap	Preferred Stock Shares Authorized PreferredStockSharesAuthorized	25000000	shares
CY2013Q4	us-gaap	Preferred Stock Shares Authorized PreferredStockSharesAuthorized	25000000	shares
CY2014Q3	us-gaap	Preferred Stock Shares Issued PreferredStockSharesIssued	7431667	shares
CY2013Q4	us-gaap	Preferred Stock Shares Issued PreferredStockSharesIssued	9431667	shares
CY2013Q4	us-gaap	Preferred Stock Shares Outstanding PreferredStockSharesOutstanding	9431667	shares
CY2014Q3	us-gaap	Preferred Stock Shares Outstanding PreferredStockSharesOutstanding	7431667	shares
CY2013Q4	us-gaap	Prepaid Expense And Other Assets PrepaidExpenseAndOtherAssets	54186000	USD
CY2014Q3	us-gaap	Prepaid Expense And Other Assets PrepaidExpenseAndOtherAssets	74863000	USD
CY2013Q4	us-gaap	Prepaid Expense Current And Noncurrent PrepaidExpenseCurrentAndNoncurrent	19308000	USD
CY2014Q3	us-gaap	Prepaid Expense Current And Noncurrent PrepaidExpenseCurrentAndNoncurrent	24497000	USD
	us-gaap	Prior Period Reclassification Adjustment Description PriorPeriodReclassificationAdjustmentDescription	<div style="font-family:Times New Roman;font-size:10pt;"><div style="line-height:120%;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;font-weight:bold;">Reclassifications</font></div><div style="line-height:120%;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"> </font></div><div style="line-height:120%;text-indent:24px;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">We reclassified certain amounts from prior periods to conform to the current period presentation of our consolidated financial statements with no effect on previously reported net income or equity.  These reclassifications occurred in conjunction with the transfer of properties to, and from, discontinued operations during 2013.</font></div></div>
	us-gaap	Proceeds From Collection Of Notes Receivable ProceedsFromCollectionOfNotesReceivable	10278000	USD
	us-gaap	Proceeds From Collection Of Notes Receivable ProceedsFromCollectionOfNotesReceivable	144000	USD
	us-gaap	Proceeds From Issuance Of Common Stock ProceedsFromIssuanceOfCommonStock	157307000	USD
	us-gaap	Proceeds From Issuance Of Common Stock ProceedsFromIssuanceOfCommonStock	1352000	USD
	us-gaap	Proceeds From Issuance Of Other Long Term Debt ProceedsFromIssuanceOfOtherLongTermDebt	82886000	USD
	us-gaap	Proceeds From Issuance Of Other Long Term Debt ProceedsFromIssuanceOfOtherLongTermDebt	11569000	USD
	us-gaap	Proceeds From Issuance Of Senior Long Term Debt ProceedsFromIssuanceOfSeniorLongTermDebt	297342000	USD
	us-gaap	Proceeds From Issuance Of Senior Long Term Debt ProceedsFromIssuanceOfSeniorLongTermDebt	592413000	USD
	us-gaap	Proceeds From Long Term Lines Of Credit ProceedsFromLongTermLinesOfCredit	115000000	USD
	us-gaap	Proceeds From Long Term Lines Of Credit ProceedsFromLongTermLinesOfCredit	457000000	USD
	us-gaap	Proceeds From Payments For Other Financing Activities ProceedsFromPaymentsForOtherFinancingActivities	-685000	USD
	us-gaap	Proceeds From Payments For Other Financing Activities ProceedsFromPaymentsForOtherFinancingActivities	-2582000	USD
	us-gaap	Proceeds From Payments For Trading Securities ProceedsFromPaymentsForTradingSecurities	0	USD
	us-gaap	Proceeds From Sale Of Real Estate Heldforinvestment ProceedsFromSaleOfRealEstateHeldforinvestment	57973000	USD
CY2014Q3	us-gaap	Rental Properties RentalProperties	2757207000	USD
CY2014Q3	us-gaap	Profit Loss ProfitLoss	24548000	USD
	us-gaap	Profit Loss ProfitLoss	8872000	USD
	us-gaap	Profit Loss ProfitLoss	39269000	USD
CY2013Q3	us-gaap	Profit Loss ProfitLoss	-2000000	USD
CY2014Q3	us-gaap	Property Plant And Equipment Additions PropertyPlantAndEquipmentAdditions	22793000	USD
CY2013Q3	us-gaap	Property Plant And Equipment Additions PropertyPlantAndEquipmentAdditions	13942000	USD
CY2013Q4	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	6556000	USD
CY2014Q3	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	6527000	USD
CY2014Q3	us-gaap	Real Estate Investment Property Net RealEstateInvestmentPropertyNet	3271156000	USD
CY2013Q4	us-gaap	Real Estate Investment Property Net RealEstateInvestmentPropertyNet	3214301000	USD
CY2014Q3	us-gaap	Real Estate Revenue Net RealEstateRevenueNet	118240000	USD
CY2013Q3	us-gaap	Real Estate Revenue Net RealEstateRevenueNet	124561000	USD
	us-gaap	Real Estate Revenue Net RealEstateRevenueNet	371913000	USD
	us-gaap	Real Estate Revenue Net RealEstateRevenueNet	359100000	USD
CY2013Q4	us-gaap	Redeemable Noncontrolling Interest Equity Carrying Amount RedeemableNoncontrollingInterestEquityCarryingAmount	17758000	USD
CY2014Q3	us-gaap	Redeemable Noncontrolling Interest Equity Carrying Amount RedeemableNoncontrollingInterestEquityCarryingAmount	18436000	USD
CY2013Q4	us-gaap	Redeemable Noncontrolling Interest Equity Fair Value RedeemableNoncontrollingInterestEquityFairValue	17758000	USD
CY2013Q3	us-gaap	Redeemable Noncontrolling Interest Equity Fair Value RedeemableNoncontrollingInterestEquityFairValue	16789000	USD
CY2014Q3	us-gaap	Redeemable Noncontrolling Interest Equity Fair Value RedeemableNoncontrollingInterestEquityFairValue	18436000	USD
CY2012Q4	us-gaap	Redeemable Noncontrolling Interest Equity Fair Value RedeemableNoncontrollingInterestEquityFairValue	10298000	USD
	us-gaap	Revenues Revenues	394558000	USD
CY2013Q4	us-gaap	Rental Properties RentalProperties	2702693000	USD
	us-gaap	Repayments Of Long Term Lines Of Credit RepaymentsOfLongTermLinesOfCredit	115000000	USD
	us-gaap	Repayments Of Long Term Lines Of Credit RepaymentsOfLongTermLinesOfCredit	457000000	USD
	us-gaap	Repayments Of Other Long Term Debt RepaymentsOfOtherLongTermDebt	183059000	USD
	us-gaap	Repayments Of Other Long Term Debt RepaymentsOfOtherLongTermDebt	542532000	USD
CY2013Q3	us-gaap	Revenues Revenues	131812000	USD
	us-gaap	Revenues Revenues	439502000	USD
CY2014Q3	us-gaap	Revenues Revenues	153015000	USD
	us-gaap	Stock Issued During Period Shares Stock Options Exercised StockIssuedDuringPeriodSharesStockOptionsExercised	57888	shares
	ofc	Acquisitionof Noncontrolling Interestin Other Consolidated Entity AcquisitionofNoncontrollingInterestinOtherConsolidatedEntity	5194000	USD
CY2014Q3	ofc	Additional Costs Incurred Related To Construction And Environmental Regulatory Activities Maximum Per Annum AdditionalCostsIncurredRelatedToConstructionAndEnvironmentalRegulatoryActivitiesMaximumPerAnnum	300000	USD
	us-gaap	Selling General And Administrative Expense SellingGeneralAndAdministrativeExpense	22430000	USD
	us-gaap	Selling General And Administrative Expense SellingGeneralAndAdministrativeExpense	22882000	USD
CY2014Q3	us-gaap	Selling General And Administrative Expense SellingGeneralAndAdministrativeExpense	7211000	USD
CY2013Q3	us-gaap	Selling General And Administrative Expense SellingGeneralAndAdministrativeExpense	8027000	USD
	us-gaap	Share Based Compensation ShareBasedCompensation	4869000	USD
	us-gaap	Share Based Compensation ShareBasedCompensation	4563000	USD
	us-gaap	Stock Issued During Period Shares Conversion Of Units StockIssuedDuringPeriodSharesConversionOfUnits	310889	shares
	us-gaap	Stock Issued During Period Shares Conversion Of Units StockIssuedDuringPeriodSharesConversionOfUnits	117149	shares
	us-gaap	Stock Issued During Period Shares Stock Options Exercised StockIssuedDuringPeriodSharesStockOptionsExercised	32756	shares
	us-gaap	Stock Issued During Period Value New Issues StockIssuedDuringPeriodValueNewIssues	117961000	USD
	us-gaap	Stock Issued During Period Value Stock Options Exercised StockIssuedDuringPeriodValueStockOptionsExercised	1359000	USD
	us-gaap	Stock Issued During Period Value Stock Options Exercised StockIssuedDuringPeriodValueStockOptionsExercised	642000	USD
	us-gaap	Stock Redeemed Or Called During Period Value StockRedeemedOrCalledDuringPeriodValue	84750000	USD
	us-gaap	Stock Redeemed Or Called During Period Value StockRedeemedOrCalledDuringPeriodValue	50000000	USD
	us-gaap	Stock Repurchased During Period Shares StockRepurchasedDuringPeriodShares	51681	shares
	us-gaap	Stock Repurchased During Period Shares StockRepurchasedDuringPeriodShares	71523	shares
	us-gaap	Stock Repurchased During Period Value StockRepurchasedDuringPeriodValue	1389000	USD
	us-gaap	Stock Repurchased During Period Value StockRepurchasedDuringPeriodValue	1848000	USD
CY2013Q4	us-gaap	Stockholders Equity StockholdersEquity	1425584000	USD
CY2014Q3	us-gaap	Stockholders Equity StockholdersEquity	1330136000	USD
CY2013Q4	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	1497249000	USD
CY2014Q3	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	1397504000	USD
CY2013Q3	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	1434067000	USD
CY2012Q4	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	1436499000	USD
	us-gaap	Straight Line Rent StraightLineRent	2738000	USD
	us-gaap	Straight Line Rent StraightLineRent	7995000	USD
CY2014Q3	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	87485000	shares
	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	87365000	shares
CY2013Q3	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	86760000	shares
	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	84547000	shares
CY2013Q3	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	86760000	shares
CY2014Q3	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	87290000	shares
	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	84547000	shares
	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	87196000	shares
	ofc	Acquisitionof Noncontrolling Interestin Other Consolidated Entity AcquisitionofNoncontrollingInterestinOtherConsolidatedEntity	0	USD
CY2014Q3	ofc	Additional Costs Incurred Related To Construction And Environmental Regulatory Activities Percentage AdditionalCostsIncurredRelatedToConstructionAndEnvironmentalRegulatoryActivitiesPercentage	0.5
CY2013Q4	ofc	Advance Rent And Security Deposit Liability AdvanceRentAndSecurityDepositLiability	31492000	USD
CY2014Q3	ofc	Advance Rent And Security Deposit Liability AdvanceRentAndSecurityDepositLiability	33075000	USD
CY2014Q3	ofc	Allowancefor Doubtful Accounts Deferred Rent AllowanceforDoubtfulAccountsDeferredRent	1426000	USD
CY2014Q3	ofc	Disposal Group Including Discontinued Operation Property Operating Expense DisposalGroupIncludingDiscontinuedOperationPropertyOperatingExpense	-175000	USD
	ofc	Disposal Group Including Discontinued Operation Property Operating Expense DisposalGroupIncludingDiscontinuedOperationPropertyOperatingExpense	-111000	USD
CY2013Q4	ofc	Allowancefor Doubtful Accounts Deferred Rent AllowanceforDoubtfulAccountsDeferredRent	2126000	USD
	ofc	Business Development Expenses And Land Carry Costs BusinessDevelopmentExpensesAndLandCarryCosts	4069000	USD
CY2014Q3	ofc	Business Development Expenses And Land Carry Costs BusinessDevelopmentExpensesAndLandCarryCosts	1430000	USD
	ofc	Business Development Expenses And Land Carry Costs BusinessDevelopmentExpensesAndLandCarryCosts	4107000	USD
CY2013Q3	ofc	Business Development Expenses And Land Carry Costs BusinessDevelopmentExpensesAndLandCarryCosts	1383000	USD
	ofc	Comprehensive Income Loss Net Of Tax After Redeemable Noncontrolling Interest Adjustments ComprehensiveIncomeLossNetOfTaxAfterRedeemableNoncontrollingInterestAdjustments	35055000	USD
	ofc	Comprehensive Income Loss Net Of Tax After Redeemable Noncontrolling Interest Adjustments ComprehensiveIncomeLossNetOfTaxAfterRedeemableNoncontrollingInterestAdjustments	16885000	USD
	ofc	Construction Contract And Other Service Expenses ConstructionContractAndOtherServiceExpenses	49165000	USD
CY2013Q3	ofc	Construction Contract And Other Service Expenses ConstructionContractAndOtherServiceExpenses	16306000	USD
CY2014Q3	ofc	Construction Contract And Other Service Expenses ConstructionContractAndOtherServiceExpenses	33593000	USD
	ofc	Construction Contract And Other Service Expenses ConstructionContractAndOtherServiceExpenses	75353000	USD
	ofc	Construction Contract And Other Service Expenses Paid ConstructionContractAndOtherServiceExpensesPaid	58218000	USD
	ofc	Construction Contract And Other Service Expenses Paid ConstructionContractAndOtherServiceExpensesPaid	53191000	USD
	ofc	Construction Contract And Other Service Revenues Received ConstructionContractAndOtherServiceRevenuesReceived	48877000	USD
	ofc	Construction Contract And Other Service Revenues Received ConstructionContractAndOtherServiceRevenuesReceived	62170000	USD
CY2013Q3	ofc	Depreciation And Amortization For Real Estate Operations DepreciationAndAmortizationForRealEstateOperations	28205000	USD
CY2014Q3	ofc	Depreciation And Amortization For Real Estate Operations DepreciationAndAmortizationForRealEstateOperations	30237000	USD
	ofc	Depreciation And Amortization For Real Estate Operations DepreciationAndAmortizationForRealEstateOperations	82888000	USD
	ofc	Depreciation And Amortization For Real Estate Operations DepreciationAndAmortizationForRealEstateOperations	104728000	USD
CY2013Q3	ofc	Discontinued Operation Gain Loss On Sale Of Real Estate DiscontinuedOperationGainLossOnSaleOfRealEstate	0	USD
	ofc	Discontinued Operation Gain Loss On Sale Of Real Estate DiscontinuedOperationGainLossOnSaleOfRealEstate	24000	USD
	ofc	Discontinued Operation Gain Loss On Sale Of Real Estate DiscontinuedOperationGainLossOnSaleOfRealEstate	0	USD
CY2014Q3	ofc	Discontinued Operation Gain Loss On Sale Of Real Estate DiscontinuedOperationGainLossOnSaleOfRealEstate	28000	USD
CY2013Q3	ofc	Disposal Group Including Discontinued Operation Depreciation And Amortization For Real Estate Operations DisposalGroupIncludingDiscontinuedOperationDepreciationAndAmortizationForRealEstateOperations	1005000	USD
	ofc	Disposal Group Including Discontinued Operation Depreciation And Amortization For Real Estate Operations DisposalGroupIncludingDiscontinuedOperationDepreciationAndAmortizationForRealEstateOperations	0	USD
	ofc	Disposal Group Including Discontinued Operation Depreciation And Amortization For Real Estate Operations DisposalGroupIncludingDiscontinuedOperationDepreciationAndAmortizationForRealEstateOperations	3509000	USD
CY2014Q3	ofc	Disposal Group Including Discontinued Operation Depreciation And Amortization For Real Estate Operations DisposalGroupIncludingDiscontinuedOperationDepreciationAndAmortizationForRealEstateOperations	0	USD
	ofc	Disposal Group Including Discontinued Operation Gains Losses On Extinguishment Of Debt DisposalGroupIncludingDiscontinuedOperationGainsLossesOnExtinguishmentOfDebt	-116000	USD
	ofc	Disposal Group Including Discontinued Operation Gains Losses On Extinguishment Of Debt DisposalGroupIncludingDiscontinuedOperationGainsLossesOnExtinguishmentOfDebt	0	USD
CY2013Q3	ofc	Disposal Group Including Discontinued Operation Gains Losses On Extinguishment Of Debt DisposalGroupIncludingDiscontinuedOperationGainsLossesOnExtinguishmentOfDebt	0	USD
CY2014Q3	ofc	Disposal Group Including Discontinued Operation Gains Losses On Extinguishment Of Debt DisposalGroupIncludingDiscontinuedOperationGainsLossesOnExtinguishmentOfDebt	0	USD
CY2013Q3	ofc	Disposal Group Including Discontinued Operation Operating Income Loss Excluding Depreciation And Amortization DisposalGroupIncludingDiscontinuedOperationOperatingIncomeLossExcludingDepreciationAndAmortization	-6216000	USD
	ofc	Disposal Group Including Discontinued Operation Operating Income Loss Excluding Depreciation And Amortization DisposalGroupIncludingDiscontinuedOperationOperatingIncomeLossExcludingDepreciationAndAmortization	-99000	USD
CY2014Q3	ofc	Disposal Group Including Discontinued Operation Operating Income Loss Excluding Depreciation And Amortization DisposalGroupIncludingDiscontinuedOperationOperatingIncomeLossExcludingDepreciationAndAmortization	-139000	USD
	ofc	Disposal Group Including Discontinued Operation Operating Income Loss Excluding Depreciation And Amortization DisposalGroupIncludingDiscontinuedOperationOperatingIncomeLossExcludingDepreciationAndAmortization	-18880000	USD
	ofc	Disposal Group Including Discontinued Operation Property Operating Expense DisposalGroupIncludingDiscontinuedOperationPropertyOperatingExpense	10523000	USD
CY2013Q3	ofc	Disposal Group Including Discontinued Operation Property Operating Expense DisposalGroupIncludingDiscontinuedOperationPropertyOperatingExpense	3524000	USD
CY2013Q4	ofc	Mortgage And Other Investing Receivables MortgageAndOtherInvestingReceivables	53663000	USD
CY2014Q3	ofc	Mortgage And Other Investing Receivables MortgageAndOtherInvestingReceivables	50886000	USD
CY2013Q3	ofc	Disposal Group Including Discontinued Operations General And Administrative And Leasing Expenses DisposalGroupIncludingDiscontinuedOperationsGeneralAndAdministrativeAndLeasingExpenses	0	USD
CY2014Q3	ofc	Disposal Group Including Discontinued Operations General And Administrative And Leasing Expenses DisposalGroupIncludingDiscontinuedOperationsGeneralAndAdministrativeAndLeasingExpenses	0	USD
CY2014Q3	ofc	Environmental Indemnification To Tenant Against Consequential Damages After Acquisition Of Property Maximum EnvironmentalIndemnificationToTenantAgainstConsequentialDamagesAfterAcquisitionOfPropertyMaximum	12500000.0	USD
CY2014Q3	ofc	Environmental Indemnification To Tenant Against Losses Covered Under Prior Owner Indemnity Agreement Maximum EnvironmentalIndemnificationToTenantAgainstLossesCoveredUnderPriorOwnerIndemnityAgreementMaximum	5000000.0	USD
	ofc	Equity Change Adjustments To Additional Paid In Capital Reallocation Of Minority Interest EquityChangeAdjustmentsToAdditionalPaidInCapitalReallocationOfMinorityInterest	773000	USD
	ofc	Equity Change Adjustments To Additional Paid In Capital Reallocation Of Minority Interest EquityChangeAdjustmentsToAdditionalPaidInCapitalReallocationOfMinorityInterest	248000	USD
	ofc	Equity Change Stock Issued During Period Value Conversion Of Units EquityChangeStockIssuedDuringPeriodValueConversionOfUnits	3991000	USD
	ofc	Equity Change Stock Issued During Period Value Conversion Of Units EquityChangeStockIssuedDuringPeriodValueConversionOfUnits	1545000	USD
	ofc	Extinguishment Of Debt Non Cash Loss ExtinguishmentOfDebtNonCashLoss	458000	USD
	ofc	Extinguishment Of Debt Non Cash Loss ExtinguishmentOfDebtNonCashLoss	3059000	USD
CY2014Q3	ofc	Number Of Primary Office Property Segments NumberOfPrimaryOfficePropertySegments	10	segment
	ofc	General And Administrative And Leasing And Business Development Expenses Paid GeneralAndAdministrativeAndLeasingAndBusinessDevelopmentExpensesPaid	22288000	USD
	ofc	General And Administrative And Leasing And Business Development Expenses Paid GeneralAndAdministrativeAndLeasingAndBusinessDevelopmentExpensesPaid	20681000	USD
	ofc	Impairment Of Properties To Be Disposed Discontinued Operations ImpairmentOfPropertiesToBeDisposedDiscontinuedOperations	3000	USD
CY2014Q3	ofc	Impairment Of Properties To Be Disposed Discontinued Operations ImpairmentOfPropertiesToBeDisposedDiscontinuedOperations	-24000	USD
	ofc	Impairment Of Properties To Be Disposed Discontinued Operations ImpairmentOfPropertiesToBeDisposedDiscontinuedOperations	25269000	USD
CY2013Q3	ofc	Impairment Of Properties To Be Disposed Discontinued Operations ImpairmentOfPropertiesToBeDisposedDiscontinuedOperations	16217000	USD
	ofc	Increase Decrease In Accrued Capital Improvements Leasing And Other Investing Activity Costs IncreaseDecreaseInAccruedCapitalImprovementsLeasingAndOtherInvestingActivityCosts	-13094000	USD
	ofc	Increase Decrease In Accrued Capital Improvements Leasing And Other Investing Activity Costs IncreaseDecreaseInAccruedCapitalImprovementsLeasingAndOtherInvestingActivityCosts	-174000	USD
	ofc	Increase Decrease In Advance Rent And Security Deposit Liability IncreaseDecreaseInAdvanceRentAndSecurityDepositLiability	1583000	USD
	ofc	Increase Decrease In Advance Rent And Security Deposit Liability IncreaseDecreaseInAdvanceRentAndSecurityDepositLiability	907000	USD
	ofc	Increase Decrease In Fair Value Of Derivatives Applied To Aocl And Noncontrolling Interests IncreaseDecreaseInFairValueOfDerivativesAppliedToAoclAndNoncontrollingInterests	7785000	USD
	ofc	Increase Decrease In Fair Value Of Derivatives Applied To Aocl And Noncontrolling Interests IncreaseDecreaseInFairValueOfDerivativesAppliedToAoclAndNoncontrollingInterests	-2613000	USD
	ofc	Increase Decrease In Marketable Securities And Restricted Cash IncreaseDecreaseInMarketableSecuritiesAndRestrictedCash	2591000	USD
	ofc	Increase Decrease In Marketable Securities And Restricted Cash IncreaseDecreaseInMarketableSecuritiesAndRestrictedCash	-418000	USD
	ofc	Interest And Other Income Received InterestAndOtherIncomeReceived	391000	USD
	ofc	Interest And Other Income Received InterestAndOtherIncomeReceived	448000	USD
CY2014Q3	ofc	Maximum Additional Costs Incurred Related To Construction And Environmental Regulatory Activities MaximumAdditionalCostsIncurredRelatedToConstructionAndEnvironmentalRegulatoryActivities	1500000.0	USD
	ofc	Minority Interest Decrease From Distributions Including Joint Ventures MinorityInterestDecreaseFromDistributionsIncludingJointVentures	8000	USD
	ofc	Minority Interest Decrease From Distributions Including Joint Ventures MinorityInterestDecreaseFromDistributionsIncludingJointVentures	1606000	USD
	ofc	Minority Interest Decrease From Distributions To Operating Partnership Noncontrolling Interest Holders MinorityInterestDecreaseFromDistributionsToOperatingPartnershipNoncontrollingInterestHolders	3710000	USD
	ofc	Minority Interest Decrease From Distributions To Operating Partnership Noncontrolling Interest Holders MinorityInterestDecreaseFromDistributionsToOperatingPartnershipNoncontrollingInterestHolders	3681000	USD
	ofc	Minority Interest In Net Income Loss Other Including Joint Ventures Minority Interests MinorityInterestInNetIncomeLossOtherIncludingJointVenturesMinorityInterests	2481000	USD
	ofc	Minority Interest In Net Income Loss Other Including Joint Ventures Minority Interests MinorityInterestInNetIncomeLossOtherIncludingJointVenturesMinorityInterests	2160000	USD
CY2013Q3	ofc	Minority Interest In Net Income Loss Other Including Joint Ventures Minority Interests MinorityInterestInNetIncomeLossOtherIncludingJointVenturesMinorityInterests	1031000	USD
CY2014Q3	ofc	Minority Interest In Net Income Loss Other Including Joint Ventures Minority Interests MinorityInterestInNetIncomeLossOtherIncludingJointVenturesMinorityInterests	895000	USD
	ofc	Minority Interest Increase From Contributions Including Joint Ventures MinorityInterestIncreaseFromContributionsIncludingJointVentures	3000	USD
	ofc	Minority Interest Increase From Contributions Including Joint Ventures MinorityInterestIncreaseFromContributionsIncludingJointVentures	85000	USD
	ofc	Net Operating Income Loss From Service Operations NetOperatingIncomeLossFromServiceOperations	5037000	USD
	ofc	Noncontrolling Interest Increasefrom Subsidiary Equity Issuance Propertyand Subsidiary Noncontrolling Interest NoncontrollingInterestIncreasefromSubsidiaryEquityIssuancePropertyandSubsidiaryNoncontrollingInterest	1369000	USD
	ofc	Settlement Of Previously Accreted Interest Expense SettlementOfPreviouslyAccretedInterestExpense	11116000	USD
	ofc	Share Based Compensation Recognized ShareBasedCompensationRecognized	5702000	USD
CY2014Q3	ofc	Net Income Loss Attributableto Common Stockholders Basicand Diluted NetIncomeLossAttributabletoCommonStockholdersBasicandDiluted	19064000	USD
CY2013Q3	ofc	Net Income Loss Attributableto Common Stockholders Basicand Diluted NetIncomeLossAttributabletoCommonStockholdersBasicandDiluted	-7551000	USD
	ofc	Net Income Loss Attributableto Common Stockholders Basicand Diluted NetIncomeLossAttributabletoCommonStockholdersBasicandDiluted	-12011000	USD
	ofc	Net Income Loss Attributableto Common Stockholders Basicand Diluted NetIncomeLossAttributabletoCommonStockholdersBasicandDiluted	20863000	USD
CY2014Q3	ofc	Net Income Lossfrom Continuing Operations Availableto Common Stockholders Basicand Diluted NetIncomeLossfromContinuingOperationsAvailabletoCommonStockholdersBasicandDiluted	18881000	USD
	ofc	Net Income Lossfrom Continuing Operations Availableto Common Stockholders Basicand Diluted NetIncomeLossfromContinuingOperationsAvailabletoCommonStockholdersBasicandDiluted	3675000	USD
CY2013Q3	ofc	Net Income Lossfrom Continuing Operations Availableto Common Stockholders Basicand Diluted NetIncomeLossfromContinuingOperationsAvailabletoCommonStockholdersBasicandDiluted	4931000	USD
	ofc	Net Income Lossfrom Continuing Operations Availableto Common Stockholders Basicand Diluted NetIncomeLossfromContinuingOperationsAvailabletoCommonStockholdersBasicandDiluted	20854000	USD
CY2013Q3	ofc	Net Operating Income Loss From Service Operations NetOperatingIncomeLossFromServiceOperations	685000	USD
CY2014Q3	ofc	Net Operating Income Loss From Service Operations NetOperatingIncomeLossFromServiceOperations	1146000	USD
	ofc	Net Operating Income Loss From Service Operations NetOperatingIncomeLossFromServiceOperations	2883000	USD
CY2014Q3	ofc	Other Minority Interests Including Joint Ventures OtherMinorityInterestsIncludingJointVentures	8787000	USD
CY2013Q4	ofc	Other Minority Interests Including Joint Ventures OtherMinorityInterestsIncludingJointVentures	9397000	USD
	ofc	Payments Of Exit Costs Included In Impairment Losses In Connection With Dispositions PaymentsOfExitCostsIncludedInImpairmentLossesInConnectionWithDispositions	0	USD
	ofc	Payments Of Exit Costs Included In Impairment Losses In Connection With Dispositions PaymentsOfExitCostsIncludedInImpairmentLossesInConnectionWithDispositions	186000	USD
	ofc	Previously Accreted Interest Expense Paid PreviouslyAccretedInterestExpensePaid	11116000	USD
	ofc	Previously Accreted Interest Expense Paid PreviouslyAccretedInterestExpensePaid	0	USD
	ofc	Property Operating Expenses Paid PropertyOperatingExpensesPaid	133799000	USD
	ofc	Property Operating Expenses Paid PropertyOperatingExpensesPaid	141489000	USD
CY2014Q3	ofc	Property Subject To Environmental Indemnity Lease Agreement Number Of Properties PropertySubjectToEnvironmentalIndemnityLeaseAgreementNumberOfProperties	3	Property
	ofc	Redeemable Noncontrolling Interest Equity Net Income Loss Attributableto Noncontrolling Interest RedeemableNoncontrollingInterestEquityNetIncomeLossAttributabletoNoncontrollingInterest	1647000	USD
CY2013Q4	ofc	Restricted Cash And Marketable Securities RestrictedCashAndMarketableSecurities	11448000	USD
CY2014Q3	ofc	Restricted Cash And Marketable Securities RestrictedCashAndMarketableSecurities	14371000	USD
	ofc	Revenues From Real Estate Operations Received RevenuesFromRealEstateOperationsReceived	358212000	USD
	ofc	Revenues From Real Estate Operations Received RevenuesFromRealEstateOperationsReceived	359431000	USD
	ofc	Share Based Compensation Recognized ShareBasedCompensationRecognized	5249000	USD
	ofc	Stock Issued During Period Value New Issuesfor Other Program StockIssuedDuringPeriodValueNewIssuesforOtherProgram	38447000	USD
CY2010Q3	ofc	Tax Incremental Financing Bonds Amount Issued By Anne Arundel County Maryland TaxIncrementalFinancingBondsAmountIssuedByAnneArundelCountyMaryland	30000000	USD
	ofc	Undistributed Earnings Loss Allocatedto Participating Securities Basicand Diluted UndistributedEarningsLossAllocatedtoParticipatingSecuritiesBasicandDiluted	332000	USD
CY2014Q3	ofc	Undistributed Earnings Loss Allocatedto Participating Securities Basicand Diluted UndistributedEarningsLossAllocatedtoParticipatingSecuritiesBasicandDiluted	103000	USD
CY2013Q3	ofc	Undistributed Earnings Loss Allocatedto Participating Securities Basicand Diluted UndistributedEarningsLossAllocatedtoParticipatingSecuritiesBasicandDiluted	97000	USD
	ofc	Undistributed Earnings Loss Allocatedto Participating Securities Basicand Diluted UndistributedEarningsLossAllocatedtoParticipatingSecuritiesBasicandDiluted	317000	USD
	dei	Amendment Flag AmendmentFlag	false
	dei	Current Fiscal Year End Date CurrentFiscalYearEndDate	--12-31
	dei	Document Fiscal Period Focus DocumentFiscalPeriodFocus	Q3
	dei	Document Fiscal Year Focus DocumentFiscalYearFocus	2014
	dei	Document Period End Date DocumentPeriodEndDate	2014-09-30
	dei	Document Type DocumentType	10-Q
	ofc	Scheduled Principal Amortization Repayments Of Long Term Debt ScheduledPrincipalAmortizationRepaymentsOfLongTermDebt	7229000	USD
	ofc	Scheduled Principal Amortization Repayments Of Long Term Debt ScheduledPrincipalAmortizationRepaymentsOfLongTermDebt	4914000	USD
CY2014Q3	ofc	Segment Reporting Direct Costs Of Leased And Rented Property Or Equipment SegmentReportingDirectCostsOfLeasedAndRentedPropertyOrEquipment	42881000	USD
CY2013Q3	ofc	Segment Reporting Direct Costs Of Leased And Rented Property Or Equipment SegmentReportingDirectCostsOfLeasedAndRentedPropertyOrEquipment	44885000	USD
	ofc	Segment Reporting Direct Costs Of Leased And Rented Property Or Equipment SegmentReportingDirectCostsOfLeasedAndRentedPropertyOrEquipment	133605000	USD
	ofc	Segment Reporting Direct Costs Of Leased And Rented Property Or Equipment SegmentReportingDirectCostsOfLeasedAndRentedPropertyOrEquipment	136489000	USD
CY2013Q3	ofc	Segment Reporting Operating Income SegmentReportingOperatingIncome	79676000	USD
CY2014Q3	ofc	Segment Reporting Operating Income SegmentReportingOperatingIncome	75359000	USD
	ofc	Segment Reporting Operating Income SegmentReportingOperatingIncome	222611000	USD
	ofc	Segment Reporting Operating Income SegmentReportingOperatingIncome	238308000	USD
CY2014Q3	ofc	Segment Reporting Transfers From Non Operating Properties SegmentReportingTransfersFromNonOperatingProperties	42802000	USD
CY2013Q3	ofc	Segment Reporting Transfers From Non Operating Properties SegmentReportingTransfersFromNonOperatingProperties	42842000	USD
	ofc	Settlement Of Previously Accreted Interest Expense SettlementOfPreviouslyAccretedInterestExpense	0	USD
	dei	Entity Central Index Key EntityCentralIndexKey	0000860546
CY2014Q4	dei	Entity Common Stock Shares Outstanding EntityCommonStockSharesOutstanding	87711731	shares
	dei	Entity Filer Category EntityFilerCategory	Large Accelerated Filer
	dei	Entity Registrant Name EntityRegistrantName	CORPORATE OFFICE PROPERTIES TRUST

Files In Submission

Name	View Source	Status
0000860546-14-000043-index-headers.html	Edgar Link	pending
0000860546-14-000043-index.html	Edgar Link	pending
0000860546-14-000043.txt	Edgar Link	pending
0000860546-14-000043-xbrl.zip	Edgar Link	pending
copt0930201410qdocument.htm	Edgar Link	pending
copt09302014ex121.htm	Edgar Link	pending
copt09302014ex122.htm	Edgar Link	pending
copt09302014ex311.htm	Edgar Link	pending
copt09302014ex312.htm	Edgar Link	pending
copt09302014ex313.htm	Edgar Link	pending
copt09302014ex314.htm	Edgar Link	pending
copt09302014ex321.htm	Edgar Link	pending
copt09302014ex322.htm	Edgar Link	pending
copt09302014ex323.htm	Edgar Link	pending
copt09302014ex324.htm	Edgar Link	pending
FilingSummary.xml	Edgar Link	unprocessable
Financial_Report.xls	Edgar Link	pending
Financial_Report.xlsx	Edgar Link	pending
ofc-20140930.xml	Edgar Link	completed
ofc-20140930.xsd	Edgar Link	pending
ofc-20140930_cal.xml	Edgar Link	unprocessable
ofc-20140930_def.xml	Edgar Link	unprocessable
ofc-20140930_lab.xml	Edgar Link	unprocessable
ofc-20140930_pre.xml	Edgar Link	unprocessable
R1.htm	Edgar Link	pending
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report.css	Edgar Link	pending
Show.js	Edgar Link	pending

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$CDP
COPT Defense Properties Stock $cdp

2014 Q4 Form 10-Q Financial Statement

#000086054614000043 Filed on October 28, 2014

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$CDP COPT Defense Properties Stock $cdp

2014 Q4 Form 10-Q Financial Statement

#000086054614000043 Filed on October 28, 2014

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$CDP
COPT Defense Properties Stock $cdp