$CDP
COPT Defense Properties Stock $cdp

$cdp Overview Financials Valuation SEC Filings Company Website

2012 Q2 Form 10-Q Financial Statement

#000144530512002318 Filed on July 27, 2012

Income Statement

Concept	2012 Q2	2011 Q2
Revenue	$123.1M	$131.8M
YoY Change	-6.65%	0.64%
Cost Of Revenue	$16.29M	$63.80M
YoY Change	-74.47%	0.0%
Gross Profit	$106.8M	$62.80M
YoY Change	70.05%	-6.69%
Gross Profit Margin	86.77%	47.63%
Selling, General & Admin	$8.851M	$6.300M
YoY Change	40.49%	6.78%
% of Gross Profit	8.29%	10.03%
Research & Development	$1.300M	$1.300M
YoY Change	0.0%	160.0%
% of Gross Profit	1.22%	2.07%
Depreciation & Amortization	$32.30M	$32.70M
YoY Change	-1.22%	8.64%
% of Gross Profit	30.25%	52.07%
Operating Expenses	$8.851M	$32.50M
YoY Change	-72.77%	-5.52%
Operating Profit	$32.07M	$16.60M
YoY Change	93.19%	-49.54%
Interest Expense	-$23.60M	-$22.40M
YoY Change	5.36%	-11.11%
% of Operating Profit	-73.59%	-134.94%
Other Income/Expense, Net
YoY Change
Pretax Income	$9.926M	-$9.130M
YoY Change	-208.72%	-220.13%
Income Tax	$17.00K	-$5.042M
% Of Pretax Income	0.17%
Net Earnings	$11.31M	-$23.41M
YoY Change	-148.28%	-389.06%
Net Earnings / Revenue	9.19%	-17.76%
Basic Earnings Per Share	$0.10	-$0.40
Diluted Earnings Per Share	$0.10	-$0.41
COMMON SHARES
Basic Shares Outstanding	71.62M shares	68.45M shares
Diluted Shares Outstanding	71.65M shares	72.83M shares

Balance Sheet

Concept	2012 Q2	2011 Q2
SHORT-TERM ASSETS
Cash & Short-Term Investments	$4.700M	$11.70M
YoY Change	-59.83%	18.18%
Cash & Equivalents	$4.702M	$11.70M
Short-Term Investments
Other Short-Term Assets	$73.90M	$101.6M
YoY Change	-27.26%	53.94%
Inventory	$144.4M
Prepaid Expenses
Receivables	$11.00M	$13.10M
Other Receivables	$0.00	$84.40M
Total Short-Term Assets	$234.0M	$210.8M
YoY Change	11.01%	28.46%
LONG-TERM ASSETS
Property, Plant & Equipment	$9.248M	$3.398B
YoY Change	-99.73%	8.54%
Goodwill
YoY Change
Intangibles	$76.43M
YoY Change
Long-Term Investments
YoY Change
Other Assets	$86.50M	$160.3M
YoY Change	-46.04%	109.54%
Total Long-Term Assets	$3.481B	$3.657B
YoY Change	-4.82%	10.72%
TOTAL ASSETS
Total Short-Term Assets	$234.0M	$210.8M
Total Long-Term Assets	$3.481B	$3.657B
Total Assets	$3.715B	$3.868B
YoY Change	-3.96%	11.56%
SHORT-TERM LIABILITIES
YoY Change
Accounts Payable	$84.70M	$115.2M
YoY Change	-26.48%	36.82%
Accrued Expenses
YoY Change
Deferred Revenue
YoY Change
Short-Term Debt	$0.00	$0.00
YoY Change
Long-Term Debt Due
YoY Change
Total Short-Term Liabilities	$136.5M	$177.0M
YoY Change	-22.88%	25.44%
LONG-TERM LIABILITIES
Long-Term Debt	$2.192B	$2.299B
YoY Change	-4.68%	5.36%
Other Long-Term Liabilities	$33.30M	$38.50M
YoY Change	-13.51%	19.2%
Total Long-Term Liabilities	$2.225B	$2.338B
YoY Change	-4.82%	5.56%
TOTAL LIABILITIES
Total Short-Term Liabilities	$136.5M	$177.0M
Total Long-Term Liabilities	$2.225B	$2.338B
Total Liabilities	$2.362B	$2.609B
YoY Change	-9.47%	6.58%
SHAREHOLDERS EQUITY
Retained Earnings
YoY Change
Common Stock	$721.0K
YoY Change
Preferred Stock
YoY Change
Treasury Stock (at cost)
YoY Change
Treasury Stock Shares
Shareholders Equity	$1.274B	$1.260B
YoY Change
Total Liabilities & Shareholders Equity	$3.715B	$3.868B
YoY Change	-3.96%	11.56%

Cashflow Statement

Concept	2012 Q2	2011 Q2
OPERATING ACTIVITIES
Net Income	$11.31M	-$23.41M
YoY Change	-148.28%	-389.06%
Depreciation, Depletion And Amortization	$32.30M	$32.70M
YoY Change	-1.22%	8.64%
Cash From Operating Activities	$68.10M	$59.50M
YoY Change	14.45%	38.69%
INVESTING ACTIVITIES
Capital Expenditures	-$44.00M	-$66.40M
YoY Change	-33.73%	-31.05%
Acquisitions
YoY Change
Other Investing Activities	$60.80M	-$9.600M
YoY Change	-733.33%	134.15%
Cash From Investing Activities	$16.80M	-$75.90M
YoY Change	-122.13%	-24.33%
FINANCING ACTIVITIES
Cash Dividend Paid
YoY Change
Common Stock Issuance & Retirement, Net
YoY Change
Debt Paid & Issued, Net
YoY Change
Cash From Financing Activities	-88.10M	15.50M
YoY Change	-668.39%	-72.9%
NET CHANGE
Cash From Operating Activities	68.10M	59.50M
Cash From Investing Activities	16.80M	-75.90M
Cash From Financing Activities	-88.10M	15.50M
Net Change In Cash	-3.200M	-900.0K
YoY Change	255.56%	350.0%
FREE CASH FLOW
Cash From Operating Activities	$68.10M	$59.50M
Capital Expenditures	-$44.00M	-$66.40M
Free Cash Flow	$112.1M	$125.9M
YoY Change	-10.96%	-9.55%

Facts In Submission

Frame	Concept Type	Concept / XBRL Key	Value	Unit
	us-gaap	Gains Losses On Extinguishment Of Debt GainsLossesOnExtinguishmentOfDebt	-25000	USD
	us-gaap	Gains Losses On Extinguishment Of Debt GainsLossesOnExtinguishmentOfDebt	-169000	USD
	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	-0.45
	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	9239000	USD
	ofc	Increase Decrease In Fair Value Of Derivatives Applied To Aocl And Noncontrolling Interests IncreaseDecreaseInFairValueOfDerivativesAppliedToAoclAndNoncontrollingInterests	6358000	USD
	ofc	Increase Decrease In Fair Value Of Derivatives Applied To Aocl And Noncontrolling Interests IncreaseDecreaseInFairValueOfDerivativesAppliedToAoclAndNoncontrollingInterests	2255000	USD
CY2011Q4	us-gaap	Accounts Payable And Accrued Liabilities Current And Noncurrent AccountsPayableAndAccruedLiabilitiesCurrentAndNoncurrent	96425000	USD
CY2012Q2	us-gaap	Accounts Payable And Accrued Liabilities Current And Noncurrent AccountsPayableAndAccruedLiabilitiesCurrentAndNoncurrent	84733000	USD
CY2011Q4	us-gaap	Accounts Receivable Net AccountsReceivableNet	26032000	USD
CY2012Q2	us-gaap	Accounts Receivable Net AccountsReceivableNet	10992000	USD
CY2012Q2	us-gaap	Accumulated Distributions In Excess Of Net Income AccumulatedDistributionsInExcessOfNetIncome	562678000	USD
CY2011Q4	us-gaap	Accumulated Distributions In Excess Of Net Income AccumulatedDistributionsInExcessOfNetIncome	532288000	USD
CY2011Q4	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	-1733000	USD
CY2012Q2	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	-3717000	USD
CY2011Q4	us-gaap	Additional Paid In Capital AdditionalPaidInCapital	1452393000	USD
CY2012Q2	us-gaap	Additional Paid In Capital AdditionalPaidInCapital	1450923000	USD
	us-gaap	Additions To Noncurrent Assets AdditionsToNoncurrentAssets	35217000	USD
CY2011Q2	us-gaap	Additions To Noncurrent Assets AdditionsToNoncurrentAssets	17017000	USD
CY2012Q2	us-gaap	Additions To Noncurrent Assets AdditionsToNoncurrentAssets	9726000	USD
	us-gaap	Additions To Noncurrent Assets AdditionsToNoncurrentAssets	14304000	USD
	us-gaap	Adjustments To Additional Paid In Capital Reallocation Of Minority Interest AdjustmentsToAdditionalPaidInCapitalReallocationOfMinorityInterest	0	USD
	us-gaap	Adjustments To Additional Paid In Capital Reallocation Of Minority Interest AdjustmentsToAdditionalPaidInCapitalReallocationOfMinorityInterest	0	USD
	us-gaap	Adjustments To Additional Paid In Capital Stock Issued Issuance Costs AdjustmentsToAdditionalPaidInCapitalStockIssuedIssuanceCosts	5000	USD
CY2011Q4	us-gaap	Allowance For Doubtful Accounts Receivable AllowanceForDoubtfulAccountsReceivable	3546000	USD
CY2012Q2	us-gaap	Allowance For Doubtful Accounts Receivable AllowanceForDoubtfulAccountsReceivable	4193000	USD
	us-gaap	Amortization Of Debt Discount Premium AmortizationOfDebtDiscountPremium	3367000	USD
	us-gaap	Amortization Of Debt Discount Premium AmortizationOfDebtDiscountPremium	1565000	USD
	us-gaap	Amortization Of Financing Costs AmortizationOfFinancingCosts	3169000	USD
	us-gaap	Amortization Of Financing Costs AmortizationOfFinancingCosts	3461000	USD
CY2012Q2	us-gaap	Asset Impairment Charges AssetImpairmentCharges	0	USD
CY2011Q2	us-gaap	Asset Impairment Charges AssetImpairmentCharges	20183000	USD
	us-gaap	Asset Impairment Charges AssetImpairmentCharges	-2303000	USD
	us-gaap	Asset Impairment Charges AssetImpairmentCharges	47925000	USD
	us-gaap	Derivative Instruments Loss Reclassified From Accumulated Oci Into Income Effective Portion DerivativeInstrumentsLossReclassifiedFromAccumulatedOCIIntoIncomeEffectivePortion	2267000	USD
	us-gaap	Derivative Instruments Loss Reclassified From Accumulated Oci Into Income Effective Portion DerivativeInstrumentsLossReclassifiedFromAccumulatedOCIIntoIncomeEffectivePortion	2402000	USD
	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.13
	ofc	Equity Change Stock Issued During Period Value Conversion Of Units EquityChangeStockIssuedDuringPeriodValueConversionOfUnits	696000	USD
	us-gaap	Noncash Or Part Noncash Acquisition Net Nonmonetary Assets Acquired Liabilities Assumed1 NoncashOrPartNoncashAcquisitionNetNonmonetaryAssetsAcquiredLiabilitiesAssumed1	3040000	USD
	us-gaap	Noncash Or Part Noncash Acquisition Net Nonmonetary Assets Acquired Liabilities Assumed1 NoncashOrPartNoncashAcquisitionNetNonmonetaryAssetsAcquiredLiabilitiesAssumed1	0	USD
	ofc	Incremental Common Shares Attributable To Conversion Of Common Units IncrementalCommonSharesAttributableToConversionOfCommonUnits	0	shares
	ofc	Incremental Common Shares Attributable To Conversion Of Common Units IncrementalCommonSharesAttributableToConversionOfCommonUnits	4389000	shares
CY2012Q2	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	4702000	USD
CY2010Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	10102000	USD
CY2012Q2	us-gaap	Assets Assets	3715075000	USD
CY2011Q4	us-gaap	Assets Assets	3867524000	USD
CY2011Q2	us-gaap	Assets Assets	3868230000	USD
CY2011Q4	us-gaap	Assets Of Disposal Group Including Discontinued Operation AssetsOfDisposalGroupIncludingDiscontinuedOperation	116616000	USD
CY2012Q2	us-gaap	Assets Of Disposal Group Including Discontinued Operation AssetsOfDisposalGroupIncludingDiscontinuedOperation	144392000	USD
CY2011Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	5559000	USD
CY2011Q2	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	11703000	USD
	us-gaap	Cash And Cash Equivalents Period Increase Decrease CashAndCashEquivalentsPeriodIncreaseDecrease	1601000	USD
	us-gaap	Cash And Cash Equivalents Period Increase Decrease CashAndCashEquivalentsPeriodIncreaseDecrease	-857000	USD
CY2011Q4	us-gaap	Commitments And Contingencies CommitmentsAndContingencies		USD
CY2012Q2	us-gaap	Commitments And Contingencies CommitmentsAndContingencies		USD
CY2012Q2	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.275
	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.825
CY2011Q2	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.4125
	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.55
CY2011Q4	us-gaap	Common Stock Par Or Stated Value Per Share CommonStockParOrStatedValuePerShare	0.01
CY2012Q2	us-gaap	Common Stock Par Or Stated Value Per Share CommonStockParOrStatedValuePerShare	0.01
CY2011Q4	us-gaap	Common Stock Shares Authorized CommonStockSharesAuthorized	125000000	shares
CY2012Q2	us-gaap	Common Stock Shares Authorized CommonStockSharesAuthorized	125000000	shares
CY2011Q4	us-gaap	Common Stock Shares Issued CommonStockSharesIssued	72011324	shares
CY2012Q2	us-gaap	Common Stock Shares Issued CommonStockSharesIssued	72084932	shares
CY2011Q4	us-gaap	Common Stock Shares Outstanding CommonStockSharesOutstanding	72011324	shares
CY2012Q2	us-gaap	Common Stock Shares Outstanding CommonStockSharesOutstanding	72084932	shares
CY2010Q4	us-gaap	Common Stock Shares Outstanding CommonStockSharesOutstanding	66931582	shares
CY2011Q2	us-gaap	Common Stock Shares Outstanding CommonStockSharesOutstanding	71891631	shares
CY2012Q2	us-gaap	Common Stock Value CommonStockValue	721000	USD
CY2011Q4	us-gaap	Common Stock Value CommonStockValue	720000	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%;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.  Included among these reclassifications are retrospective changes in the presentation of:</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><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;">our preferred shares of beneficial interest; these shares are reported on our consolidated balance sheets at their liquidation preference value after having been reported at par value in our </font><font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;">2011</font><font style="font-family:inherit;font-size:10pt;"> Annual Report on Form 10-K; 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;">costs expensed in connection with properties not in operations; these costs are included in the line on our consolidated statements of operations entitled “business development expenses and land carry costs,” after having been included in property operating expenses in our </font><font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;">2011</font><font style="font-family:inherit;font-size:10pt;"> Annual Report on Form 10-K.</font></div></td></tr></table></div>
CY2011Q2	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	-31069000	USD
	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	-47953000	USD
CY2012Q2	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	9139000	USD
	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	15332000	USD
CY2012Q2	us-gaap	Comprehensive Income Net Of Tax Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxAttributableToNoncontrollingInterest	1011000	USD
	us-gaap	Comprehensive Income Net Of Tax Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxAttributableToNoncontrollingInterest	1282000	USD
CY2011Q2	us-gaap	Comprehensive Income Net Of Tax Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxAttributableToNoncontrollingInterest	-2233000	USD
	us-gaap	Comprehensive Income Net Of Tax Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxAttributableToNoncontrollingInterest	-2947000	USD
	us-gaap	Comprehensive Income Net Of Tax Including Portion Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest	-50900000	USD
CY2012Q2	us-gaap	Comprehensive Income Net Of Tax Including Portion Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest	10150000	USD
	us-gaap	Comprehensive Income Net Of Tax Including Portion Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest	16614000	USD
CY2011Q2	us-gaap	Comprehensive Income Net Of Tax Including Portion Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest	-33302000	USD
CY2012Q2	us-gaap	Costs And Expenses CostsAndExpenses	97562000	USD
CY2011Q2	us-gaap	Costs And Expenses CostsAndExpenses	123382000	USD
	us-gaap	Costs And Expenses CostsAndExpenses	252349000	USD
	us-gaap	Costs And Expenses CostsAndExpenses	198695000	USD
CY2011Q4	us-gaap	Deferred Rent Receivables Net DeferredRentReceivablesNet	86856000	USD
CY2012Q2	us-gaap	Deferred Rent Receivables Net DeferredRentReceivablesNet	85595000	USD
CY2011Q4	us-gaap	Deferred Tax Assets Net DeferredTaxAssetsNet	10892000	USD
CY2012Q2	us-gaap	Deferred Tax Assets Net DeferredTaxAssetsNet	6746000	USD
CY2011Q2	us-gaap	Derivative Instruments Loss Reclassified From Accumulated Oci Into Income Effective Portion DerivativeInstrumentsLossReclassifiedFromAccumulatedOCIIntoIncomeEffectivePortion	1163000	USD
CY2012Q2	us-gaap	Derivative Instruments Loss Reclassified From Accumulated Oci Into Income Effective Portion DerivativeInstrumentsLossReclassifiedFromAccumulatedOCIIntoIncomeEffectivePortion	928000	USD
	us-gaap	Derivative Instruments Loss Recognized In Other Comprehensive Income Effective Portion DerivativeInstrumentsLossRecognizedInOtherComprehensiveIncomeEffectivePortion	4626000	USD
CY2011Q2	us-gaap	Derivative Instruments Loss Recognized In Other Comprehensive Income Effective Portion DerivativeInstrumentsLossRecognizedInOtherComprehensiveIncomeEffectivePortion	8458000	USD
	us-gaap	Derivative Instruments Loss Recognized In Other Comprehensive Income Effective Portion DerivativeInstrumentsLossRecognizedInOtherComprehensiveIncomeEffectivePortion	8594000	USD
CY2012Q2	us-gaap	Derivative Instruments Loss Recognized In Other Comprehensive Income Effective Portion DerivativeInstrumentsLossRecognizedInOtherComprehensiveIncomeEffectivePortion	2639000	USD
CY2011Q4	us-gaap	Development In Process DevelopmentInProcess	638919000	USD
CY2012Q2	us-gaap	Development In Process DevelopmentInProcess	603456000	USD
CY2011Q2	us-gaap	Direct Costs Of Leased And Rented Property Or Equipment DirectCostsOfLeasedAndRentedPropertyOrEquipment	40450000	USD
	us-gaap	Direct Costs Of Leased And Rented Property Or Equipment DirectCostsOfLeasedAndRentedPropertyOrEquipment	84985000	USD
CY2012Q2	us-gaap	Direct Costs Of Leased And Rented Property Or Equipment DirectCostsOfLeasedAndRentedPropertyOrEquipment	42384000	USD
	us-gaap	Direct Costs Of Leased And Rented Property Or Equipment DirectCostsOfLeasedAndRentedPropertyOrEquipment	87301000	USD
CY2011Q2	us-gaap	Disposal Group Including Discontinued Operation Interest Expense DisposalGroupIncludingDiscontinuedOperationInterestExpense	1235000	USD
CY2012Q2	us-gaap	Disposal Group Including Discontinued Operation Interest Expense DisposalGroupIncludingDiscontinuedOperationInterestExpense	228000	USD
	us-gaap	Disposal Group Including Discontinued Operation Interest Expense DisposalGroupIncludingDiscontinuedOperationInterestExpense	983000	USD
	us-gaap	Disposal Group Including Discontinued Operation Interest Expense DisposalGroupIncludingDiscontinuedOperationInterestExpense	2495000	USD
	us-gaap	Disposal Group Including Discontinued Operation Revenue DisposalGroupIncludingDiscontinuedOperationRevenue	23710000	USD
CY2011Q2	us-gaap	Disposal Group Including Discontinued Operation Revenue DisposalGroupIncludingDiscontinuedOperationRevenue	11787000	USD
	us-gaap	Disposal Group Including Discontinued Operation Revenue DisposalGroupIncludingDiscontinuedOperationRevenue	16805000	USD
	us-gaap	Gain Loss On Sale Of Properties Net Of Applicable Income Taxes GainLossOnSaleOfPropertiesNetOfApplicableIncomeTaxes	2728000	USD
CY2012Q2	us-gaap	Disposal Group Including Discontinued Operation Revenue DisposalGroupIncludingDiscontinuedOperationRevenue	7577000	USD
	us-gaap	Dividends Dividends	65387000	USD
	us-gaap	Dividends Dividends	47821000	USD
	us-gaap	Dividends Preferred Stock Cash DividendsPreferredStockCash	8192000	USD
CY2012Q2	us-gaap	Dividends Preferred Stock Cash DividendsPreferredStockCash	4167000	USD
	us-gaap	Dividends Preferred Stock Cash DividendsPreferredStockCash	8051000	USD
CY2011Q2	us-gaap	Dividends Preferred Stock Cash DividendsPreferredStockCash	4026000	USD
	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	-0.75
CY2011Q2	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	-0.42
CY2012Q2	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.09
CY2011Q2	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	-0.42
CY2012Q2	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.09
	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	-0.75
	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.13
	us-gaap	Equity Method Investment Realized Gain Loss On Disposal EquityMethodInvestmentRealizedGainLossOnDisposal	0	USD
	us-gaap	Equity Method Investment Realized Gain Loss On Disposal EquityMethodInvestmentRealizedGainLossOnDisposal	2442000	USD
	us-gaap	Gain Loss On Sale Of Properties GainLossOnSaleOfProperties	2867000	USD
	us-gaap	Gain Loss On Sale Of Properties GainLossOnSaleOfProperties	4056000	USD
	us-gaap	Gain Loss On Sale Of Properties Net Of Applicable Income Taxes GainLossOnSaleOfPropertiesNetOfApplicableIncomeTaxes	21000	USD
CY2011Q2	us-gaap	Gain Loss On Sale Of Properties Net Of Applicable Income Taxes GainLossOnSaleOfPropertiesNetOfApplicableIncomeTaxes	27000	USD
CY2012Q2	us-gaap	Gain Loss On Sale Of Properties Net Of Applicable Income Taxes GainLossOnSaleOfPropertiesNetOfApplicableIncomeTaxes	21000	USD
CY2011Q2	us-gaap	Gains Losses On Extinguishment Of Debt GainsLossesOnExtinguishmentOfDebt	-25000	USD
CY2012Q2	us-gaap	Gains Losses On Extinguishment Of Debt GainsLossesOnExtinguishmentOfDebt	-169000	USD
	us-gaap	General And Administrative Expense GeneralAndAdministrativeExpense	14759000	USD
CY2011Q2	us-gaap	General And Administrative Expense GeneralAndAdministrativeExpense	6320000	USD
	us-gaap	General And Administrative Expense GeneralAndAdministrativeExpense	13097000	USD
CY2012Q2	us-gaap	General And Administrative Expense GeneralAndAdministrativeExpense	7742000	USD
CY2012Q2	us-gaap	Guarantee Obligations Current Carrying Value GuaranteeObligationsCurrentCarryingValue	4700000	USD
CY2011Q4	us-gaap	Incentive To Lessee IncentiveToLessee	5233000	USD
CY2012Q2	us-gaap	Incentive To Lessee IncentiveToLessee	5229000	USD
CY2011Q2	us-gaap	Income Loss Before Gain Or Loss On Sale Of Properties Extraordinary Items And Cumulative Effects Of Accounting Changes IncomeLossBeforeGainOrLossOnSaleOfPropertiesExtraordinaryItemsAndCumulativeEffectsOfAccountingChanges	-26034000	USD
	us-gaap	Income Loss Before Gain Or Loss On Sale Of Properties Extraordinary Items And Cumulative Effects Of Accounting Changes IncomeLossBeforeGainOrLossOnSaleOfPropertiesExtraordinaryItemsAndCumulativeEffectsOfAccountingChanges	18817000	USD
	us-gaap	Income Loss Before Gain Or Loss On Sale Of Properties Extraordinary Items And Cumulative Effects Of Accounting Changes IncomeLossBeforeGainOrLossOnSaleOfPropertiesExtraordinaryItemsAndCumulativeEffectsOfAccountingChanges	-47301000	USD
CY2012Q2	us-gaap	Income Loss Before Gain Or Loss On Sale Of Properties Extraordinary Items And Cumulative Effects Of Accounting Changes IncomeLossBeforeGainOrLossOnSaleOfPropertiesExtraordinaryItemsAndCumulativeEffectsOfAccountingChanges	11840000	USD
CY2012Q2	us-gaap	Income Loss From Continuing Operations IncomeLossFromContinuingOperations	10475000	USD
	us-gaap	Income Loss From Continuing Operations IncomeLossFromContinuingOperations	-21609000	USD
	us-gaap	Income Loss From Continuing Operations IncomeLossFromContinuingOperations	18603000	USD
CY2011Q2	us-gaap	Income Loss From Continuing Operations IncomeLossFromContinuingOperations	-3744000	USD
	us-gaap	Income Loss From Continuing Operations Attributable To Noncontrolling Entity IncomeLossFromContinuingOperationsAttributableToNoncontrollingEntity	1474000	USD
CY2011Q2	us-gaap	Income Loss From Continuing Operations Attributable To Noncontrolling Entity IncomeLossFromContinuingOperationsAttributableToNoncontrollingEntity	-411000	USD
	us-gaap	Income Loss From Continuing Operations Attributable To Noncontrolling Entity IncomeLossFromContinuingOperationsAttributableToNoncontrollingEntity	-1192000	USD
CY2012Q2	us-gaap	Income Loss From Continuing Operations Attributable To Noncontrolling Entity IncomeLossFromContinuingOperationsAttributableToNoncontrollingEntity	1090000	USD
CY2012Q2	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	11748000	USD
CY2011Q2	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	-9130000	USD
	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	-31051000	USD
	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	24522000	USD
CY2011Q2	us-gaap	Income Loss From Continuing Operations Including Portion Attributable To Noncontrolling Interest IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest	-4182000	USD
	us-gaap	Income Loss From Continuing Operations Including Portion Attributable To Noncontrolling Interest IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest	20056000	USD
CY2012Q2	us-gaap	Income Loss From Continuing Operations Including Portion Attributable To Noncontrolling Interest IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest	11544000	USD
	us-gaap	Income Loss From Continuing Operations Including Portion Attributable To Noncontrolling Interest IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest	-25529000	USD
CY2012Q2	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	0.09
	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	-0.45
CY2011Q2	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	-0.12
	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	0.14
CY2011Q2	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	-0.12
	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	0.14
CY2012Q2	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	0.09
	us-gaap	Income Loss From Discontinued Operations Net Of Tax IncomeLossFromDiscontinuedOperationsNetOfTax	-21772000	USD
	us-gaap	Income Loss From Discontinued Operations Net Of Tax IncomeLossFromDiscontinuedOperationsNetOfTax	-1239000	USD
CY2011Q2	us-gaap	Income Loss From Discontinued Operations Net Of Tax IncomeLossFromDiscontinuedOperationsNetOfTax	-21852000	USD
CY2012Q2	us-gaap	Income Loss From Discontinued Operations Net Of Tax IncomeLossFromDiscontinuedOperationsNetOfTax	296000	USD
CY2011Q2	us-gaap	Income Loss From Discontinued Operations Net Of Tax Attributable To Noncontrolling Interest IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToNoncontrollingInterest	-1372000	USD
	us-gaap	Income Loss From Discontinued Operations Net Of Tax Attributable To Noncontrolling Interest IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToNoncontrollingInterest	-67000	USD
CY2012Q2	us-gaap	Income Loss From Discontinued Operations Net Of Tax Attributable To Noncontrolling Interest IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToNoncontrollingInterest	17000	USD
	us-gaap	Income Loss From Discontinued Operations Net Of Tax Attributable To Noncontrolling Interest IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToNoncontrollingInterest	-1367000	USD
CY2012Q2	us-gaap	Income Loss From Discontinued Operations Net Of Tax Attributable To Reporting Entity IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity	279000	USD
CY2011Q2	us-gaap	Income Loss From Discontinued Operations Net Of Tax Attributable To Reporting Entity IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity	-20480000	USD
	us-gaap	Income Loss From Discontinued Operations Net Of Tax Attributable To Reporting Entity IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity	-20405000	USD
	us-gaap	Income Loss From Discontinued Operations Net Of Tax Attributable To Reporting Entity IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity	-1172000	USD
CY2012Q2	us-gaap	Income Loss From Discontinued Operations Net Of Tax Per Basic Share IncomeLossFromDiscontinuedOperationsNetOfTaxPerBasicShare	0.00
CY2011Q2	us-gaap	Income Loss From Discontinued Operations Net Of Tax Per Basic Share IncomeLossFromDiscontinuedOperationsNetOfTaxPerBasicShare	-0.30
	us-gaap	Income Loss From Discontinued Operations Net Of Tax Per Basic Share IncomeLossFromDiscontinuedOperationsNetOfTaxPerBasicShare	-0.01
	us-gaap	Income Loss From Discontinued Operations Net Of Tax Per Basic Share IncomeLossFromDiscontinuedOperationsNetOfTaxPerBasicShare	-0.30
CY2011Q2	us-gaap	Income Loss From Discontinued Operations Net Of Tax Per Diluted Share IncomeLossFromDiscontinuedOperationsNetOfTaxPerDilutedShare	-0.30
CY2012Q2	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	-0.01
	us-gaap	Income Loss From Discontinued Operations Net Of Tax Per Diluted Share IncomeLossFromDiscontinuedOperationsNetOfTaxPerDilutedShare	-0.30
	us-gaap	Income Loss From Equity Method Investments IncomeLossFromEquityMethodInvestments	-64000	USD
CY2012Q2	us-gaap	Income Loss From Equity Method Investments IncomeLossFromEquityMethodInvestments	-187000	USD
	us-gaap	Income Loss From Equity Method Investments IncomeLossFromEquityMethodInvestments	-276000	USD
CY2011Q2	us-gaap	Income Loss From Equity Method Investments IncomeLossFromEquityMethodInvestments	-94000	USD
CY2011Q2	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	-5042000	USD
CY2012Q2	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	17000	USD
	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	4190000	USD
	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	-5586000	USD
	us-gaap	Income Taxes Paid IncomeTaxesPaid	170000	USD
	us-gaap	Income Taxes Paid IncomeTaxesPaid	8000	USD
	us-gaap	Increase Decrease In Accounts Receivable IncreaseDecreaseInAccountsReceivable	-6044000	USD
	us-gaap	Increase Decrease In Accounts Receivable IncreaseDecreaseInAccountsReceivable	-15031000	USD
	us-gaap	Increase Decrease In Deferred Rent Receivables IncreaseDecreaseInDeferredRentReceivables	7213000	USD
	us-gaap	Increase Decrease In Deferred Rent Receivables IncreaseDecreaseInDeferredRentReceivables	4937000	USD
	us-gaap	Increase Decrease In Prepaid Deferred Expense And Other Assets IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets	-4536000	USD
	us-gaap	Increase Decrease In Prepaid Deferred Expense And Other Assets IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets	-22201000	USD
CY2012Q2	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	25000	shares
CY2011Q2	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	0	shares
	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	0	shares
	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	35000	shares
CY2011Q4	us-gaap	Intangible Assets Net Excluding Goodwill IntangibleAssetsNetExcludingGoodwill	89120000	USD
CY2012Q2	us-gaap	Intangible Assets Net Excluding Goodwill IntangibleAssetsNetExcludingGoodwill	76426000	USD
CY2012Q2	us-gaap	Interest And Debt Expense InterestAndDebtExpense	24747000	USD
	us-gaap	Interest And Debt Expense InterestAndDebtExpense	51263000	USD
	us-gaap	Interest And Debt Expense InterestAndDebtExpense	49667000	USD
CY2011Q2	us-gaap	Interest And Debt Expense InterestAndDebtExpense	25595000	USD
	us-gaap	Interest Costs Capitalized InterestCostsCapitalized	7400000	USD
CY2011Q2	us-gaap	Interest Costs Capitalized InterestCostsCapitalized	4300000	USD
	us-gaap	Interest Costs Capitalized InterestCostsCapitalized	8600000	USD
CY2012Q2	us-gaap	Interest Costs Capitalized InterestCostsCapitalized	3600000	USD
	us-gaap	Interest Paid Net InterestPaidNet	45435000	USD
	us-gaap	Interest Paid Net InterestPaidNet	47425000	USD
CY2011Q4	us-gaap	Interest Rate Derivative Liabilities At Fair Value InterestRateDerivativeLiabilitiesAtFairValue	30863000	USD
CY2012Q2	us-gaap	Interest Rate Derivative Liabilities At Fair Value InterestRateDerivativeLiabilitiesAtFairValue	4400000	USD
CY2011Q4	us-gaap	Interest Rate Derivatives At Fair Value Net InterestRateDerivativesAtFairValueNet	-30147000	USD
CY2012Q2	us-gaap	Interest Rate Derivatives At Fair Value Net InterestRateDerivativesAtFairValueNet	-4400000	USD
CY2011Q4	us-gaap	Liabilities Liabilities	2649459000	USD
CY2012Q2	us-gaap	Liabilities Liabilities	2361726000	USD
CY2011Q4	us-gaap	Liabilities And Stockholders Equity LiabilitiesAndStockholdersEquity	3867524000	USD
CY2012Q2	us-gaap	Liabilities And Stockholders Equity LiabilitiesAndStockholdersEquity	3715075000	USD
CY2011Q4	us-gaap	Loans Receivable Fair Value Disclosure LoansReceivableFairValueDisclosure	28000000	USD
CY2012Q2	us-gaap	Loans Receivable Fair Value Disclosure LoansReceivableFairValueDisclosure	38100000	USD
CY2011Q4	us-gaap	Long Term Debt LongTermDebt	2426303000	USD
CY2012Q2	us-gaap	Long Term Debt LongTermDebt	2191851000	USD
CY2011Q4	us-gaap	Minority Interest MinorityInterest	82640000	USD
CY2012Q2	us-gaap	Minority Interest MinorityInterest	79267000	USD
CY2011Q2	us-gaap	Minority Interest In Net Income Loss Operating Partnerships MinorityInterestInNetIncomeLossOperatingPartnerships	-1887000	USD
	us-gaap	Minority Interest In Net Income Loss Operating Partnerships MinorityInterestInNetIncomeLossOperatingPartnerships	549000	USD
CY2012Q2	us-gaap	Minority Interest In Net Income Loss Operating Partnerships MinorityInterestInNetIncomeLossOperatingPartnerships	390000	USD
	us-gaap	Minority Interest In Net Income Loss Operating Partnerships MinorityInterestInNetIncomeLossOperatingPartnerships	-3366000	USD
CY2012Q2	us-gaap	Minority Interest In Net Income Loss Preferred Unit Holders MinorityInterestInNetIncomeLossPreferredUnitHolders	165000	USD
CY2011Q2	us-gaap	Minority Interest In Net Income Loss Preferred Unit Holders MinorityInterestInNetIncomeLossPreferredUnitHolders	165000	USD
	us-gaap	Minority Interest In Net Income Loss Preferred Unit Holders MinorityInterestInNetIncomeLossPreferredUnitHolders	330000	USD
	us-gaap	Minority Interest In Net Income Loss Preferred Unit Holders MinorityInterestInNetIncomeLossPreferredUnitHolders	330000	USD
CY2011Q4	us-gaap	Minority Interest In Operating Partnerships MinorityInterestInOperatingPartnerships	55281000	USD
CY2012Q2	us-gaap	Minority Interest In Operating Partnerships MinorityInterestInOperatingPartnerships	52152000	USD
CY2012Q2	us-gaap	Minority Interest In Preferred Unit Holders MinorityInterestInPreferredUnitHolders	8800000	USD
CY2011Q4	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,” “we” or “us”) is a fully-integrated and self-managed real estate investment trust (“REIT”) that focuses primarily on serving the specialized requirements of strategic customers in the United States Government and defense information technology sectors.  We acquire, develop, manage and lease office and data center properties that are typically concentrated in large office parks primarily located adjacent to government demand drivers and/or in office markets that we believe possess growth opportunities.  As of </font><font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;">June 30, 2012</font><font style="font-family:inherit;font-size:10pt;">, our investments in real estate included the following:</font></div><div style="line-height:120%;text-indent:24px;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"> </font></div><table cellpadding="0" cellspacing="0" style="font-family:Times New Roman; font-size:10pt;"><tr><td style="width:48px;" 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:24px;"><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;">228</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;">19.8 million</font><font style="font-family:inherit;font-size:10pt;"> square feet;</font></div></td></tr></table><table cellpadding="0" cellspacing="0" style="font-family:Times New Roman; font-size:10pt;"><tr><td style="width:48px;" 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:24px;"><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;">nine</font><font style="font-family:inherit;font-size:10pt;"> office properties under 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, including </font><font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;">two</font><font style="font-family:inherit;font-size:10pt;"> partially operational properties included above;</font></div></td></tr></table><table cellpadding="0" cellspacing="0" style="font-family:Times New Roman; font-size:10pt;"><tr><td style="width:48px;" 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:24px;"><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;">land held or under pre-construction totaling </font><font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;">2,303</font><font style="font-family:inherit;font-size:10pt;"> acres (including </font><font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;">583</font><font style="font-family:inherit;font-size:10pt;"> controlled but not owned) that we believe are potentially developable into approximately </font><font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;">20.1 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:48px;" 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:24px;"><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%;text-indent:24px;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">We conduct almost all of our operations through our operating partnership, Corporate Office Properties, L.P. (the “Operating Partnership”), of which we are the managing general partner.  The Operating Partnership owns real estate both directly and through subsidiary partnerships and limited liability companies (“LLCs”).  A summary of our Operating Partnership’s forms of ownership and the percentage of those ownership forms owned by COPT as of </font><font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;">June 30, 2012</font><font style="font-family:inherit;font-size:10pt;"> follows:</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%;padding-left:24px;font-size:10pt;"><div style="padding-left:0px;text-indent:0px;line-height:normal;padding-top:10px;"><table cellpadding="0" cellspacing="0" style="font-family:Times New Roman;font-size:10pt;width:58.3984375%;border-collapse:collapse;text-align:left;"><tr><td colspan="3" rowspan="1"></td></tr><tr><td width="78%" rowspan="1" colspan="1"></td><td width="21%" rowspan="1" colspan="1"></td><td width="1%" rowspan="1" colspan="1"></td></tr><tr><td style="vertical-align:top;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">Common Units</font></div></td><td style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:right;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">94</font></div></td><td style="vertical-align:bottom;background-color:#cceeff;padding-right:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">%</font></div></td></tr><tr><td style="vertical-align:top;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">Series G Preferred Units</font></div></td><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:right;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">100</font></div></td><td style="vertical-align:bottom;padding-right:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">%</font></div></td></tr><tr><td style="vertical-align:top;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">Series H Preferred Units</font></div></td><td style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:right;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">100</font></div></td><td style="vertical-align:bottom;background-color:#cceeff;padding-right:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">%</font></div></td></tr><tr><td style="vertical-align:top;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">Series I Preferred Units</font></div></td><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:right;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">0</font></div></td><td style="vertical-align:bottom;padding-right:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">%</font></div></td></tr><tr><td style="vertical-align:top;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">Series J Preferred Units</font></div></td><td style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:right;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">100</font></div></td><td style="vertical-align:bottom;background-color:#cceeff;padding-right:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">%</font></div></td></tr><tr><td style="vertical-align:top;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">Series K Preferred Units</font></div></td><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:right;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">100</font></div></td><td style="vertical-align:bottom;padding-right:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">%</font></div></td></tr><tr><td style="vertical-align:top;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">Series L Preferred Units</font></div></td><td style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:right;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">100</font></div></td><td style="vertical-align:bottom;background-color:#cceeff;padding-right:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">%</font></div></td></tr></table></div><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;"> </font></div><div style="line-height:120%;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;">Three</font><font style="font-family:inherit;font-size:10pt;"> of our trustees also controlled, either directly or through ownership by other entities or family members, an additional </font><font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;">5%</font><font style="font-family:inherit;font-size:10pt;"> of the Operating Partnership’s common units (“common units”) as of </font><font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;">June 30, 2012</font><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;"> </font></div><div style="line-height:120%;text-indent:24px;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">In addition to owning real estate, the Operating Partnership also owns entities that provide real estate services such as property management and construction and development services primarily for our properties but also for third parties.</font></div><div style="line-height:120%;text-indent:24px;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"> </font></div></div>
	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	46413000	USD
	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	-137337000	USD
	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	24586000	USD
	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-137309000	USD
	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	92497000	USD
	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	111894000	USD
CY2012Q2	us-gaap	Net Income Loss NetIncomeLoss	10754000	USD
CY2011Q2	us-gaap	Net Income Loss NetIncomeLoss	-24224000	USD
	us-gaap	Net Income Loss NetIncomeLoss	17431000	USD
	us-gaap	Net Income Loss NetIncomeLoss	-42014000	USD
CY2012Q2	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	6587000	USD
	us-gaap	Payments To Acquire Notes Receivable PaymentsToAcquireNotesReceivable	15796000	USD
	us-gaap	Payments To Develop Real Estate Assets PaymentsToDevelopRealEstateAssets	99152000	USD
	us-gaap	Payments To Develop Real Estate Assets PaymentsToDevelopRealEstateAssets	71504000	USD
CY2011Q4	us-gaap	Preferred Stock Par Or Stated Value Per Share PreferredStockParOrStatedValuePerShare	0.01
CY2012Q2	us-gaap	Preferred Stock Par Or Stated Value Per Share PreferredStockParOrStatedValuePerShare	0.01
CY2011Q2	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	-28250000	USD
	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	-50065000	USD
CY2011Q2	us-gaap	Operating Income Loss OperatingIncomeLoss	13734000	USD
	us-gaap	Operating Income Loss OperatingIncomeLoss	16313000	USD
CY2012Q2	us-gaap	Operating Income Loss OperatingIncomeLoss	35824000	USD
	us-gaap	Operating Income Loss OperatingIncomeLoss	72301000	USD
CY2011Q4	us-gaap	Other Assets OtherAssets	13284000	USD
CY2012Q2	us-gaap	Other Assets OtherAssets	4998000	USD
	us-gaap	Other Comprehensive Income Derivatives Qualifying As Hedges Net Of Tax Period Increase Decrease OtherComprehensiveIncomeDerivativesQualifyingAsHedgesNetOfTaxPeriodIncreaseDecrease	-2224000	USD
	us-gaap	Other Comprehensive Income Derivatives Qualifying As Hedges Net Of Tax Period Increase Decrease OtherComprehensiveIncomeDerivativesQualifyingAsHedgesNetOfTaxPeriodIncreaseDecrease	-6327000	USD
CY2012Q2	us-gaap	Other Comprehensive Income Loss Net Of Tax Period Increase Decrease OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecrease	-1711000	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax Period Increase Decrease OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecrease	-6327000	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax Period Increase Decrease OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecrease	-2224000	USD
CY2011Q2	us-gaap	Other Comprehensive Income Loss Net Of Tax Period Increase Decrease OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecrease	-7295000	USD
CY2011Q2	us-gaap	Other Comprehensive Income Reclassification Adjustment On Derivatives Included In Net Income Net Of Tax OtherComprehensiveIncomeReclassificationAdjustmentOnDerivativesIncludedInNetIncomeNetOfTax	-1163000	USD
	us-gaap	Other Comprehensive Income Reclassification Adjustment On Derivatives Included In Net Income Net Of Tax OtherComprehensiveIncomeReclassificationAdjustmentOnDerivativesIncludedInNetIncomeNetOfTax	-2267000	USD
	us-gaap	Other Comprehensive Income Reclassification Adjustment On Derivatives Included In Net Income Net Of Tax OtherComprehensiveIncomeReclassificationAdjustmentOnDerivativesIncludedInNetIncomeNetOfTax	-2402000	USD
CY2012Q2	us-gaap	Other Comprehensive Income Reclassification Adjustment On Derivatives Included In Net Income Net Of Tax OtherComprehensiveIncomeReclassificationAdjustmentOnDerivativesIncludedInNetIncomeNetOfTax	-928000	USD
	us-gaap	Other Comprehensive Income Unrealized Gain Loss On Derivatives Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodNetOfTax	-8594000	USD
CY2011Q2	us-gaap	Other Comprehensive Income Unrealized Gain Loss On Derivatives Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodNetOfTax	-8458000	USD
CY2012Q2	us-gaap	Other Comprehensive Income Unrealized Gain Loss On Derivatives Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodNetOfTax	-2639000	USD
	us-gaap	Other Comprehensive Income Unrealized Gain Loss On Derivatives Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodNetOfTax	-4626000	USD
CY2011Q4	us-gaap	Other Liabilities OtherLiabilities	9657000	USD
CY2012Q2	us-gaap	Other Liabilities OtherLiabilities	8703000	USD
	us-gaap	Other Noncash Income Expense OtherNoncashIncomeExpense	724000	USD
	us-gaap	Other Noncash Income Expense OtherNoncashIncomeExpense	917000	USD
CY2011Q2	us-gaap	Other Nonoperating Income OtherNonoperatingIncome	2756000	USD
CY2012Q2	us-gaap	Other Nonoperating Income OtherNonoperatingIncome	840000	USD
	us-gaap	Other Nonoperating Income OtherNonoperatingIncome	3924000	USD
	us-gaap	Other Nonoperating Income OtherNonoperatingIncome	2057000	USD
	us-gaap	Payments For Capital Improvements PaymentsForCapitalImprovements	6009000	USD
	us-gaap	Payments For Capital Improvements PaymentsForCapitalImprovements	5514000	USD
	us-gaap	Payments For Proceeds From Other Investing Activities PaymentsForProceedsFromOtherInvestingActivities	991000	USD
	us-gaap	Payments For Proceeds From Other Investing Activities PaymentsForProceedsFromOtherInvestingActivities	1545000	USD
	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	3813000	USD
	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	3219000	USD
	us-gaap	Payments Of Debt Extinguishment Costs PaymentsOfDebtExtinguishmentCosts	0	USD
	us-gaap	Payments Of Debt Extinguishment Costs PaymentsOfDebtExtinguishmentCosts	156000	USD
	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	55415000	USD
	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	49507000	USD
	us-gaap	Payments Of Dividends Preferred Stock And Preference Stock PaymentsOfDividendsPreferredStockAndPreferenceStock	8051000	USD
	us-gaap	Payments Of Dividends Preferred Stock And Preference Stock PaymentsOfDividendsPreferredStockAndPreferenceStock	8051000	USD
	us-gaap	Payments Of Financing Costs PaymentsOfFinancingCosts	557000	USD
	us-gaap	Payments Of Financing Costs PaymentsOfFinancingCosts	2111000	USD
	us-gaap	Payments To Acquire Notes Receivable PaymentsToAcquireNotesReceivable	8933000	USD
CY2011Q4	us-gaap	Preferred Stock Shares Outstanding PreferredStockSharesOutstanding	8121667	shares
CY2012Q2	us-gaap	Preferred Stock Shares Outstanding PreferredStockSharesOutstanding	15021667	shares
CY2012Q2	us-gaap	Preferred Stock Value PreferredStockValue	388833000	USD
CY2011Q4	us-gaap	Preferred Stock Value PreferredStockValue	216333000	USD
CY2012Q2	us-gaap	Prepaid Expense And Other Assets PrepaidExpenseAndOtherAssets	73883000	USD
CY2011Q4	us-gaap	Prepaid Expense And Other Assets PrepaidExpenseAndOtherAssets	87619000	USD
CY2012Q2	us-gaap	Prepaid Expense Current And Noncurrent PrepaidExpenseCurrentAndNoncurrent	9541000	USD
CY2011Q4	us-gaap	Prepaid Expense Current And Noncurrent PrepaidExpenseCurrentAndNoncurrent	20035000	USD
	us-gaap	Proceeds From Issuance Of Common Stock ProceedsFromIssuanceOfCommonStock	145361000	USD
	us-gaap	Proceeds From Issuance Of Common Stock ProceedsFromIssuanceOfCommonStock	185000	USD
CY2011Q4	us-gaap	Preferred Stock Shares Authorized PreferredStockSharesAuthorized	15000000	shares
CY2012Q2	us-gaap	Preferred Stock Shares Authorized PreferredStockSharesAuthorized	25000000	shares
CY2012Q2	us-gaap	Preferred Stock Shares Issued PreferredStockSharesIssued	15021667	shares
CY2011Q4	us-gaap	Preferred Stock Shares Issued PreferredStockSharesIssued	8121667	shares
	us-gaap	Proceeds From Issuance Of Other Long Term Debt ProceedsFromIssuanceOfOtherLongTermDebt	273909000	USD
	us-gaap	Proceeds From Issuance Of Other Long Term Debt ProceedsFromIssuanceOfOtherLongTermDebt	32662000	USD
	us-gaap	Proceeds From Issuance Of Preferred Stock And Preference Stock ProceedsFromIssuanceOfPreferredStockAndPreferenceStock	165902000	USD
	us-gaap	Proceeds From Issuance Of Preferred Stock And Preference Stock ProceedsFromIssuanceOfPreferredStockAndPreferenceStock	0	USD
	us-gaap	Proceeds From Long Term Lines Of Credit ProceedsFromLongTermLinesOfCredit	252000000	USD
	us-gaap	Proceeds From Long Term Lines Of Credit ProceedsFromLongTermLinesOfCredit	101000000	USD
	us-gaap	Proceeds From Payments For Other Financing Activities ProceedsFromPaymentsForOtherFinancingActivities	-838000	USD
	us-gaap	Proceeds From Payments For Other Financing Activities ProceedsFromPaymentsForOtherFinancingActivities	3524000	USD
	us-gaap	Proceeds From Payments For Trading Securities ProceedsFromPaymentsForTradingSecurities	0	USD
	us-gaap	Proceeds From Payments For Trading Securities ProceedsFromPaymentsForTradingSecurities	18975000	USD
	us-gaap	Proceeds From Sale Of Equity Method Investments ProceedsFromSaleOfEquityMethodInvestments	0	USD
	us-gaap	Proceeds From Sale Of Equity Method Investments ProceedsFromSaleOfEquityMethodInvestments	5773000	USD
	us-gaap	Proceeds From Sale Of Real Estate Heldforinvestment ProceedsFromSaleOfRealEstateHeldforinvestment	130814000	USD
	us-gaap	Proceeds From Sale Of Real Estate Heldforinvestment ProceedsFromSaleOfRealEstateHeldforinvestment	6943000	USD
	us-gaap	Profit Loss ProfitLoss	-44573000	USD
CY2011Q2	us-gaap	Profit Loss ProfitLoss	-26007000	USD
	us-gaap	Profit Loss ProfitLoss	18838000	USD
CY2012Q2	us-gaap	Profit Loss ProfitLoss	11861000	USD
CY2012Q2	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	9248000	USD
CY2011Q4	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	10177000	USD
CY2012Q2	us-gaap	Real Estate Investment Property Net RealEstateInvestmentPropertyNet	3232592000	USD
CY2011Q4	us-gaap	Real Estate Investment Property Net RealEstateInvestmentPropertyNet	3352975000	USD
	us-gaap	Real Estate Revenue Net RealEstateRevenueNet	249272000	USD
	us-gaap	Real Estate Revenue Net RealEstateRevenueNet	243247000	USD
CY2011Q2	us-gaap	Real Estate Revenue Net RealEstateRevenueNet	120806000	USD
CY2012Q2	us-gaap	Real Estate Revenue Net RealEstateRevenueNet	123968000	USD
CY2011Q2	ofc	Construction Contract And Other Service Expenses ConstructionContractAndOtherServiceExpenses	26909000	USD
	ofc	Construction Contract And Other Service Expenses ConstructionContractAndOtherServiceExpenses	47527000	USD
	ofc	Construction Contract And Other Service Expenses Paid ConstructionContractAndOtherServiceExpensesPaid	51538000	USD
	ofc	Construction Contract And Other Service Expenses Paid ConstructionContractAndOtherServiceExpensesPaid	37296000	USD
	ofc	Construction Contract And Other Service Revenue ConstructionContractAndOtherServiceRevenue	49125000	USD
CY2011Q2	ofc	Construction Contract And Other Service Revenue ConstructionContractAndOtherServiceRevenue	28097000	USD
	ofc	Construction Contract And Other Service Revenue ConstructionContractAndOtherServiceRevenue	38529000	USD
CY2012Q2	ofc	Construction Contract And Other Service Revenue ConstructionContractAndOtherServiceRevenue	16995000	USD
	ofc	Construction Contract And Other Service Revenues Received ConstructionContractAndOtherServiceRevenuesReceived	49441000	USD
CY2011Q4	us-gaap	Rental Properties RentalProperties	2714056000	USD
CY2012Q2	us-gaap	Rental Properties RentalProperties	2629136000	USD
	us-gaap	Repayments Of Long Term Lines Of Credit RepaymentsOfLongTermLinesOfCredit	205000000	USD
	us-gaap	Repayments Of Long Term Lines Of Credit RepaymentsOfLongTermLinesOfCredit	568000000	USD
	us-gaap	Repayments Of Other Long Term Debt RepaymentsOfOtherLongTermDebt	102913000	USD
	us-gaap	Repayments Of Other Long Term Debt RepaymentsOfOtherLongTermDebt	37035000	USD
	us-gaap	Revenues Revenues	270996000	USD
	us-gaap	Revenues Revenues	268662000	USD
CY2012Q2	us-gaap	Revenues Revenues	133386000	USD
CY2011Q2	us-gaap	Revenues Revenues	137116000	USD
	us-gaap	Share Based Compensation ShareBasedCompensation	6559000	USD
	us-gaap	Share Based Compensation ShareBasedCompensation	5734000	USD
	us-gaap	Stock Issued During Period Shares Conversion Of Units StockIssuedDuringPeriodSharesConversionOfUnits	21045	shares
	us-gaap	Stock Issued During Period Shares Conversion Of Units StockIssuedDuringPeriodSharesConversionOfUnits	54550	shares
	us-gaap	Stock Issued During Period Shares New Issues StockIssuedDuringPeriodSharesNewIssues	6900000	shares
	us-gaap	Stock Issued During Period Shares New Issues StockIssuedDuringPeriodSharesNewIssues	4600000	shares
	us-gaap	Stock Issued During Period Shares Stock Options Exercised StockIssuedDuringPeriodSharesStockOptionsExercised	180464	shares
	us-gaap	Stock Issued During Period Shares Stock Options Exercised StockIssuedDuringPeriodSharesStockOptionsExercised	12667	shares
	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	145361000	USD
	us-gaap	Stock Issued During Period Value New Issues StockIssuedDuringPeriodValueNewIssues	165665000	USD
	us-gaap	Stock Issued During Period Value Stock Options Exercised StockIssuedDuringPeriodValueStockOptionsExercised	-189000	USD
	us-gaap	Stock Issued During Period Value Stock Options Exercised StockIssuedDuringPeriodValueStockOptionsExercised	-2309000	USD
	us-gaap	Stock Repurchased During Period Shares StockRepurchasedDuringPeriodShares	107442	shares
	us-gaap	Stock Repurchased During Period Shares StockRepurchasedDuringPeriodShares	133081	shares
	us-gaap	Stock Repurchased During Period Value StockRepurchasedDuringPeriodValue	3813000	USD
	us-gaap	Stock Repurchased During Period Value StockRepurchasedDuringPeriodValue	3219000	USD
CY2011Q4	us-gaap	Stockholders Equity StockholdersEquity	1135425000	USD
CY2012Q2	us-gaap	Stockholders Equity StockholdersEquity	1274082000	USD
CY2012Q2	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	1353349000	USD
CY2011Q4	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	1218065000	USD
CY2011Q2	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	1353372000	USD
CY2010Q4	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	1323138000	USD
CY2012Q2	us-gaap	Undistributed Earnings Allocated To Participating Securities UndistributedEarningsAllocatedToParticipatingSecurities	105000	USD
	us-gaap	Undistributed Earnings Allocated To Participating Securities UndistributedEarningsAllocatedToParticipatingSecurities	519000	USD
CY2011Q2	us-gaap	Undistributed Earnings Allocated To Participating Securities UndistributedEarningsAllocatedToParticipatingSecurities	237000	USD
	us-gaap	Undistributed Earnings Allocated To Participating Securities UndistributedEarningsAllocatedToParticipatingSecurities	246000	USD
	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	71576000	shares
CY2011Q2	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	72828000	shares
CY2012Q2	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	71649000	shares
	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	71788000	shares
	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	71541000	shares
CY2011Q2	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	68446000	shares
CY2012Q2	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	71624000	shares
	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	67399000	shares
CY2012Q2	ofc	Additional Costs Incurred Related To Construction And Environmental Regulatory Activities Maximum Per Annum AdditionalCostsIncurredRelatedToConstructionAndEnvironmentalRegulatoryActivitiesMaximumPerAnnum	300000	USD
CY2012Q2	ofc	Additional Costs Incurred Related To Construction And Environmental Regulatory Activities Percentage AdditionalCostsIncurredRelatedToConstructionAndEnvironmentalRegulatoryActivitiesPercentage	0.5
CY2011Q4	ofc	Advance Rent And Security Deposit Liability AdvanceRentAndSecurityDepositLiability	29548000	USD
CY2012Q2	ofc	Advance Rent And Security Deposit Liability AdvanceRentAndSecurityDepositLiability	27124000	USD
CY2011Q2	ofc	Amount Of Dilutive Effect Of Common Units On Diluted Earnings Per Share From Continuing Operations AmountOfDilutiveEffectOfCommonUnitsOnDilutedEarningsPerShareFromContinuingOperations	-517000	USD
	ofc	Amount Of Dilutive Effect Of Common Units On Diluted Earnings Per Share From Continuing Operations AmountOfDilutiveEffectOfCommonUnitsOnDilutedEarningsPerShareFromContinuingOperations	0	USD
CY2012Q2	ofc	Amount Of Dilutive Effect Of Common Units On Diluted Earnings Per Share From Continuing Operations AmountOfDilutiveEffectOfCommonUnitsOnDilutedEarningsPerShareFromContinuingOperations	0	USD
	ofc	Amount Of Dilutive Effect Of Common Units On Diluted Earnings Per Share From Continuing Operations AmountOfDilutiveEffectOfCommonUnitsOnDilutedEarningsPerShareFromContinuingOperations	-2002000	USD
	ofc	Amount Of Dilutive Securities Common Units AmountOfDilutiveSecuritiesCommonUnits	0	USD
CY2012Q2	ofc	Amount Of Dilutive Securities Common Units AmountOfDilutiveSecuritiesCommonUnits	0	USD
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CY2011Q2	ofc	Amount Of Dilutive Securities Common Units AmountOfDilutiveSecuritiesCommonUnits	-1887000	USD
	ofc	Asset Impairment Charges Continuing And Noncontinuing Operations AssetImpairmentChargesContinuingAndNoncontinuingOperations	72347000	USD
	ofc	Asset Impairment Charges Continuing And Noncontinuing Operations AssetImpairmentChargesContinuingAndNoncontinuingOperations	7693000	USD
CY2012Q1	ofc	Asset Impairment Charges Continuing And Noncontinuing Operations Including Exit Costs AssetImpairmentChargesContinuingAndNoncontinuingOperationsIncludingExitCosts	6587000	USD
	ofc	Asset Impairment Charges Continuing And Noncontinuing Operations Including Exit Costs AssetImpairmentChargesContinuingAndNoncontinuingOperationsIncludingExitCosts	8941000	USD
CY2012Q2	ofc	Asset Impairment Charges Continuing And Noncontinuing Operations Including Exit Costs AssetImpairmentChargesContinuingAndNoncontinuingOperationsIncludingExitCosts	2354000	USD
	ofc	Business Development Expenses And Land Carry Costs BusinessDevelopmentExpensesAndLandCarryCosts	2874000	USD
CY2011Q2	ofc	Business Development Expenses And Land Carry Costs BusinessDevelopmentExpensesAndLandCarryCosts	1349000	USD
	ofc	Business Development Expenses And Land Carry Costs BusinessDevelopmentExpensesAndLandCarryCosts	2571000	USD
CY2012Q2	ofc	Business Development Expenses And Land Carry Costs BusinessDevelopmentExpensesAndLandCarryCosts	1298000	USD
	ofc	Common Stock Conversion Basis For Common Unit CommonStockConversionBasisForCommonUnit	1	shares
	ofc	Construction Contract And Other Service Expenses ConstructionContractAndOtherServiceExpenses	36892000	USD
CY2012Q2	ofc	Construction Contract And Other Service Expenses ConstructionContractAndOtherServiceExpenses	16285000	USD
	ofc	Construction Contract And Other Service Revenues Received ConstructionContractAndOtherServiceRevenuesReceived	46933000	USD
CY2011Q4	ofc	Deferred Leasing And Financing Costs Net DeferredLeasingAndFinancingCostsNet	66515000	USD
CY2012Q2	ofc	Deferred Leasing And Financing Costs Net DeferredLeasingAndFinancingCostsNet	63861000	USD
CY2011Q4	ofc	Deferred Revenue Operating Leases DeferredRevenueOperatingLeases	15554000	USD
CY2012Q2	ofc	Deferred Revenue Operating Leases DeferredRevenueOperatingLeases	13938000	USD
	ofc	Depreciation And Amortization For Real Estate Operations DepreciationAndAmortizationForRealEstateOperations	59172000	USD
CY2012Q2	ofc	Depreciation And Amortization For Real Estate Operations DepreciationAndAmortizationForRealEstateOperations	29853000	USD
	ofc	Depreciation And Amortization For Real Estate Operations DepreciationAndAmortizationForRealEstateOperations	56244000	USD
CY2011Q2	ofc	Depreciation And Amortization For Real Estate Operations DepreciationAndAmortizationForRealEstateOperations	28171000	USD
	ofc	Depreciation And Other Amortization Excluding Amortization On Financing Costs DepreciationAndOtherAmortizationExcludingAmortizationOnFinancingCosts	64000000	USD
	ofc	Depreciation And Other Amortization Excluding Amortization On Financing Costs DepreciationAndOtherAmortizationExcludingAmortizationOnFinancingCosts	66317000	USD
	ofc	Discontinued Operation Gain Loss On Sale Of Real Estate DiscontinuedOperationGainLossOnSaleOfRealEstate	4035000	USD
	ofc	Discontinued Operation Gain Loss On Sale Of Real Estate DiscontinuedOperationGainLossOnSaleOfRealEstate	139000	USD
CY2012Q2	ofc	Discontinued Operation Gain Loss On Sale Of Real Estate DiscontinuedOperationGainLossOnSaleOfRealEstate	-103000	USD
CY2011Q2	ofc	Discontinued Operation Gain Loss On Sale Of Real Estate DiscontinuedOperationGainLossOnSaleOfRealEstate	139000	USD
CY2011Q2	ofc	Disposal Group Including Discontinued Operation Business Development And Land Carry Costs DisposalGroupIncludingDiscontinuedOperationBusinessDevelopmentAndLandCarryCosts	20000	USD
	ofc	Disposal Group Including Discontinued Operation Business Development And Land Carry Costs DisposalGroupIncludingDiscontinuedOperationBusinessDevelopmentAndLandCarryCosts	39000	USD
	ofc	Disposal Group Including Discontinued Operation Business Development And Land Carry Costs DisposalGroupIncludingDiscontinuedOperationBusinessDevelopmentAndLandCarryCosts	24000	USD
CY2012Q2	ofc	Disposal Group Including Discontinued Operation Business Development And Land Carry Costs DisposalGroupIncludingDiscontinuedOperationBusinessDevelopmentAndLandCarryCosts	6000	USD
CY2011Q2	ofc	Disposal Group Including Discontinued Operation Depreciation And Amortization For Real Estate Operations DisposalGroupIncludingDiscontinuedOperationDepreciationAndAmortizationForRealEstateOperations	3878000	USD
	ofc	Disposal Group Including Discontinued Operation Depreciation And Amortization For Real Estate Operations DisposalGroupIncludingDiscontinuedOperationDepreciationAndAmortizationForRealEstateOperations	8825000	USD
	ofc	Disposal Group Including Discontinued Operation Depreciation And Amortization For Real Estate Operations DisposalGroupIncludingDiscontinuedOperationDepreciationAndAmortizationForRealEstateOperations	3581000	USD
CY2012Q2	ofc	Disposal Group Including Discontinued Operation Depreciation And Amortization For Real Estate Operations DisposalGroupIncludingDiscontinuedOperationDepreciationAndAmortizationForRealEstateOperations	1813000	USD
	ofc	Disposal Group Including Discontinued Operation Gains Losses On Extinguishment Of Debt DisposalGroupIncludingDiscontinuedOperationGainsLossesOnExtinguishmentOfDebt	-2000	USD
	ofc	Disposal Group Including Discontinued Operation Gains Losses On Extinguishment Of Debt DisposalGroupIncludingDiscontinuedOperationGainsLossesOnExtinguishmentOfDebt	0	USD
CY2011Q2	ofc	Disposal Group Including Discontinued Operation Gains Losses On Extinguishment Of Debt DisposalGroupIncludingDiscontinuedOperationGainsLossesOnExtinguishmentOfDebt	0	USD
CY2012Q2	ofc	Disposal Group Including Discontinued Operation Gains Losses On Extinguishment Of Debt DisposalGroupIncludingDiscontinuedOperationGainsLossesOnExtinguishmentOfDebt	-2000	USD
	ofc	Disposal Group Including Discontinued Operation Operating Income Loss Excluding Depreciation And Amortization DisposalGroupIncludingDiscontinuedOperationOperatingIncomeLossExcludingDepreciationAndAmortization	-10560000	USD
	ofc	Disposal Group Including Discontinued Operation Operating Income Loss Excluding Depreciation And Amortization DisposalGroupIncludingDiscontinuedOperationOperatingIncomeLossExcludingDepreciationAndAmortization	-13870000	USD
CY2011Q2	ofc	Disposal Group Including Discontinued Operation Operating Income Loss Excluding Depreciation And Amortization DisposalGroupIncludingDiscontinuedOperationOperatingIncomeLossExcludingDepreciationAndAmortization	-7564000	USD
CY2012Q2	ofc	Disposal Group Including Discontinued Operation Operating Income Loss Excluding Depreciation And Amortization DisposalGroupIncludingDiscontinuedOperationOperatingIncomeLossExcludingDepreciationAndAmortization	-4802000	USD
CY2011Q2	ofc	Disposal Group Including Discontinued Operation Property Operating Expense DisposalGroupIncludingDiscontinuedOperationPropertyOperatingExpense	4223000	USD
	ofc	Disposal Group Including Discontinued Operation Property Operating Expense DisposalGroupIncludingDiscontinuedOperationPropertyOperatingExpense	6245000	USD
	ofc	Disposal Group Including Discontinued Operation Property Operating Expense DisposalGroupIncludingDiscontinuedOperationPropertyOperatingExpense	9840000	USD
CY2012Q2	ofc	Disposal Group Including Discontinued Operation Property Operating Expense DisposalGroupIncludingDiscontinuedOperationPropertyOperatingExpense	2775000	USD
CY2012Q2	ofc	Distributions Received In Excess Of Investment In Unconsolidated Real Estate Joint Venture DistributionsReceivedInExcessOfInvestmentInUnconsolidatedRealEstateJointVenture	6282000	USD
CY2012Q2	ofc	Environmental Indemnification To Tenant Against Losses Covered Under Prior Owner Indemnity Agreement Maximum EnvironmentalIndemnificationToTenantAgainstLossesCoveredUnderPriorOwnerIndemnityAgreementMaximum	5000000	USD
	ofc	Equity Change Adjustments To Additional Paid In Capital Reallocation Of Minority Interest EquityChangeAdjustmentsToAdditionalPaidInCapitalReallocationOfMinorityInterest	4778000	USD
	ofc	Equity Change Adjustments To Additional Paid In Capital Reallocation Of Minority Interest EquityChangeAdjustmentsToAdditionalPaidInCapitalReallocationOfMinorityInterest	524000	USD
	ofc	Equity Change Stock Issued During Period Value Conversion Of Units EquityChangeStockIssuedDuringPeriodValueConversionOfUnits	328000	USD
CY2011Q4	ofc	Distributions Received In Excess Of Investment In Unconsolidated Real Estate Joint Venture DistributionsReceivedInExcessOfInvestmentInUnconsolidatedRealEstateJointVenture	6071000	USD
CY2011Q4	ofc	Dividends And Distributions Payable DividendsAndDistributionsPayable	35038000	USD
CY2012Q2	ofc	Dividends And Distributions Payable DividendsAndDistributionsPayable	24695000	USD
CY2012Q2	ofc	Dividends Distributions Payable DividendsDistributionsPayable	24695000	USD
CY2011Q2	ofc	Dividends Distributions Payable DividendsDistributionsPayable	35021000	USD
CY2012Q2	ofc	Environmental Indemnification To Tenant Against Consequential Damages After Acquisition Of Property In Years EnvironmentalIndemnificationToTenantAgainstConsequentialDamagesAfterAcquisitionOfPropertyInYears	15	Y
CY2012Q2	ofc	Environmental Indemnification To Tenant Against Consequential Damages After Acquisition Of Property Maximum EnvironmentalIndemnificationToTenantAgainstConsequentialDamagesAfterAcquisitionOfPropertyMaximum	12500000	USD
	ofc	Exit Costs Included In Impairment Losses In Connection With Disposition Plan ExitCostsIncludedInImpairmentLossesInConnectionWithDispositionPlan	1200000	USD
	ofc	General And Administrative And Business Development Expenses Paid GeneralAndAdministrativeAndBusinessDevelopmentExpensesPaid	10124000	USD
	ofc	General And Administrative And Business Development Expenses Paid GeneralAndAdministrativeAndBusinessDevelopmentExpensesPaid	10429000	USD
	ofc	Impairment Of Properties In Connection With Disposition Plan Aggregate ImpairmentOfPropertiesInConnectionWithDispositionPlanAggregate	8900000	USD
	ofc	Impairment Of Properties In Connection With Disposition Plan In Discontinued Operations ImpairmentOfPropertiesInConnectionWithDispositionPlanInDiscontinuedOperations	11200000	USD
CY2011Q2	ofc	Impairment Of Properties To Be Disposed Discontinued Operations ImpairmentOfPropertiesToBeDisposedDiscontinuedOperations	24422000	USD
CY2012Q2	ofc	Impairment Of Properties To Be Disposed Discontinued Operations ImpairmentOfPropertiesToBeDisposedDiscontinuedOperations	2354000	USD
	ofc	Impairment Of Properties To Be Disposed Discontinued Operations ImpairmentOfPropertiesToBeDisposedDiscontinuedOperations	24422000	USD
	ofc	Impairment Of Properties To Be Disposed Discontinued Operations ImpairmentOfPropertiesToBeDisposedDiscontinuedOperations	11244000	USD
	ofc	Impairment On Expected Dispostion Of Additional Property ImpairmentOnExpectedDispostionOfAdditionalProperty	5100000	USD
	ofc	Increase Decrease In Accounts Payable And Other Accrued Liabilities IncreaseDecreaseInAccountsPayableAndOtherAccruedLiabilities	-907000	USD
	ofc	Increase Decrease In Accounts Payable And Other Accrued Liabilities IncreaseDecreaseInAccountsPayableAndOtherAccruedLiabilities	-7522000	USD
	ofc	Increase Decrease In Accrued Capital Improvements Leasing And Other Investing Activity Costs IncreaseDecreaseInAccruedCapitalImprovementsLeasingAndOtherInvestingActivityCosts	-12081000	USD
	ofc	Increase Decrease In Accrued Capital Improvements Leasing And Other Investing Activity Costs IncreaseDecreaseInAccruedCapitalImprovementsLeasingAndOtherInvestingActivityCosts	23053000	USD
	ofc	Increase Decrease In Advance Rent And Security Deposit Liability IncreaseDecreaseInAdvanceRentAndSecurityDepositLiability	-2424000	USD
	ofc	Increase Decrease In Advance Rent And Security Deposit Liability IncreaseDecreaseInAdvanceRentAndSecurityDepositLiability	-4824000	USD
	ofc	Increase Decrease In Interest Rate Derivatives In Connection With Cash Settlement IncreaseDecreaseInInterestRateDerivativesInConnectionWithCashSettlement	-28003000	USD
	ofc	Increase Decrease In Interest Rate Derivatives In Connection With Cash Settlement IncreaseDecreaseInInterestRateDerivativesInConnectionWithCashSettlement	0	USD
	ofc	Increase Decrease In Marketable Securities And Restricted Cash IncreaseDecreaseInMarketableSecuritiesAndRestrictedCash	-14082000	USD
	ofc	Increase Decrease In Marketable Securities And Restricted Cash IncreaseDecreaseInMarketableSecuritiesAndRestrictedCash	-856000	USD
CY2012Q2	ofc	Incremental Common Shares Attributable To Conversion Of Common Units IncrementalCommonSharesAttributableToConversionOfCommonUnits	0	shares
CY2011Q2	ofc	Incremental Common Shares Attributable To Conversion Of Common Units IncrementalCommonSharesAttributableToConversionOfCommonUnits	4382000	shares
	ofc	Interest And Other Income Received InterestAndOtherIncomeReceived	529000	USD
	ofc	Interest And Other Income Received InterestAndOtherIncomeReceived	250000	USD
CY2012Q2	ofc	Maximum Additional Costs Incurred Related To Construction And Environmental Regulatory Activities MaximumAdditionalCostsIncurredRelatedToConstructionAndEnvironmentalRegulatoryActivities	1500000	USD
	ofc	Minority Interest Decrease From Distributions Including Joint Ventures MinorityInterestDecreaseFromDistributionsIncludingJointVentures	648000	USD
	ofc	Minority Interest Decrease From Distributions Including Joint Ventures MinorityInterestDecreaseFromDistributionsIncludingJointVentures	8000	USD
	ofc	Minority Interest Decrease From Distributions To Operating Partnership Noncontrolling Interest Holders MinorityInterestDecreaseFromDistributionsToOperatingPartnershipNoncontrollingInterestHolders	3947000	USD
	ofc	Minority Interest Decrease From Distributions To Operating Partnership Noncontrolling Interest Holders MinorityInterestDecreaseFromDistributionsToOperatingPartnershipNoncontrollingInterestHolders	2672000	USD
CY2011Q2	ofc	Minority Interest In Net Income Loss Other Including Joint Ventures Minority Interests MinorityInterestInNetIncomeLossOtherIncludingJointVenturesMinorityInterests	-61000	USD
	ofc	Minority Interest In Net Income Loss Other Including Joint Ventures Minority Interests MinorityInterestInNetIncomeLossOtherIncludingJointVenturesMinorityInterests	477000	USD
	ofc	Minority Interest In Net Income Loss Other Including Joint Ventures Minority Interests MinorityInterestInNetIncomeLossOtherIncludingJointVenturesMinorityInterests	528000	USD
CY2012Q2	ofc	Minority Interest In Net Income Loss Other Including Joint Ventures Minority Interests MinorityInterestInNetIncomeLossOtherIncludingJointVenturesMinorityInterests	552000	USD
	ofc	Minority Interest Increase From Contributions Including Joint Ventures MinorityInterestIncreaseFromContributionsIncludingJointVentures	-261000	USD
CY2012Q2	ofc	Mortgage And Other Investing Receivables MortgageAndOtherInvestingReceivables	38121000	USD
CY2011Q4	ofc	Mortgage And Other Investing Receivables MortgageAndOtherInvestingReceivables	27998000	USD
	ofc	Net Income Loss Attributable To Common Stockholders Basic NetIncomeLossAttributableToCommonStockholdersBasic	8993000	USD
CY2011Q2	ofc	Net Income Loss Attributable To Common Stockholders Basic NetIncomeLossAttributableToCommonStockholdersBasic	-28487000	USD
CY2012Q2	ofc	Net Income Loss Attributable To Common Stockholders Basic NetIncomeLossAttributableToCommonStockholdersBasic	6482000	USD
	ofc	Net Income Loss Attributable To Common Stockholders Basic NetIncomeLossAttributableToCommonStockholdersBasic	-50584000	USD
	ofc	Net Income Loss Attributable To Common Stockholders Dilutive NetIncomeLossAttributableToCommonStockholdersDilutive	-53950000	USD
CY2012Q2	ofc	Net Income Loss Attributable To Common Stockholders Dilutive NetIncomeLossAttributableToCommonStockholdersDilutive	6482000	USD
	ofc	Net Income Loss Attributable To Common Stockholders Dilutive NetIncomeLossAttributableToCommonStockholdersDilutive	8993000	USD
CY2011Q2	ofc	Net Income Loss Attributable To Common Stockholders Dilutive NetIncomeLossAttributableToCommonStockholdersDilutive	-30374000	USD
CY2011Q2	ofc	Net Income Loss From Continuing Operations Available To Common Stockholders Basic NetIncomeLossFromContinuingOperationsAvailableToCommonStockholdersBasic	-8007000	USD
CY2012Q2	ofc	Net Income Loss From Continuing Operations Available To Common Stockholders Basic NetIncomeLossFromContinuingOperationsAvailableToCommonStockholdersBasic	6203000	USD
	ofc	Net Income Loss From Continuing Operations Available To Common Stockholders Basic NetIncomeLossFromContinuingOperationsAvailableToCommonStockholdersBasic	10165000	USD
	ofc	Net Income Loss From Continuing Operations Available To Common Stockholders Basic NetIncomeLossFromContinuingOperationsAvailableToCommonStockholdersBasic	-30179000	USD
CY2011Q2	ofc	Net Income Loss From Continuing Operations Available To Common Stockholders Dilutive NetIncomeLossFromContinuingOperationsAvailableToCommonStockholdersDilutive	-8524000	USD
CY2012Q2	ofc	Net Income Loss From Continuing Operations Available To Common Stockholders Dilutive NetIncomeLossFromContinuingOperationsAvailableToCommonStockholdersDilutive	6203000	USD
	ofc	Net Income Loss From Continuing Operations Available To Common Stockholders Dilutive NetIncomeLossFromContinuingOperationsAvailableToCommonStockholdersDilutive	10165000	USD
	ofc	Net Income Loss From Continuing Operations Available To Common Stockholders Dilutive NetIncomeLossFromContinuingOperationsAvailableToCommonStockholdersDilutive	-32181000	USD
CY2011Q2	ofc	Net Operating Income Loss From Service Operations NetOperatingIncomeLossFromServiceOperations	1188000	USD
	ofc	Net Operating Income Loss From Service Operations NetOperatingIncomeLossFromServiceOperations	1637000	USD
	ofc	Net Operating Income Loss From Service Operations NetOperatingIncomeLossFromServiceOperations	1598000	USD
CY2012Q2	ofc	Net Operating Income Loss From Service Operations NetOperatingIncomeLossFromServiceOperations	710000	USD
CY2012Q2	ofc	Number Of Primary Office Property Segments NumberOfPrimaryOfficePropertySegments	10	segments
	ofc	Operating Partnership Unit Conversion Rate To Shares OperatingPartnershipUnitConversionRateToShares	54550	shares
CY2012Q2	ofc	Other Minority Interests Including Joint Ventures OtherMinorityInterestsIncludingJointVentures	18315000	USD
CY2011Q4	ofc	Other Minority Interests Including Joint Ventures OtherMinorityInterestsIncludingJointVentures	18559000	USD
	ofc	Payments For Derivative Instrument Operating Activities PaymentsForDerivativeInstrumentOperatingActivities	29738000	USD
	ofc	Payments For Derivative Instrument Operating Activities PaymentsForDerivativeInstrumentOperatingActivities	0	USD
CY2012Q1	ofc	Payments For Derivative Instrument Operating Activities PaymentsForDerivativeInstrumentOperatingActivities	29700000	USD
	ofc	Payments For Leasing Costs PaymentsForLeasingCosts	5489000	USD
	ofc	Payments For Leasing Costs PaymentsForLeasingCosts	6802000	USD
	ofc	Payments Of Capital Distribution To Noncontrolling Interest In Operating Partnership PaymentsOfCapitalDistributionToNoncontrollingInterestInOperatingPartnership	3269000	USD
	ofc	Payments Of Capital Distribution To Noncontrolling Interest In Operating Partnership PaymentsOfCapitalDistributionToNoncontrollingInterestInOperatingPartnership	3964000	USD
	ofc	Property Operating Expenses Paid PropertyOperatingExpensesPaid	80528000	USD
	ofc	Property Operating Expenses Paid PropertyOperatingExpensesPaid	81173000	USD
CY2012Q2	ofc	Property Subject To Environmental Indemnity Lease Agreement Number Of Properties PropertySubjectToEnvironmentalIndemnityLeaseAgreementNumberOfProperties	3	Property
	ofc	Rental Revenue RentalRevenue	179436000	USD
CY2012Q2	ofc	Rental Revenue RentalRevenue	94502000	USD
	ofc	Rental Revenue RentalRevenue	188394000	USD
CY2011Q2	ofc	Rental Revenue RentalRevenue	90337000	USD
CY2011Q4	ofc	Restricted Cash And Marketable Securities RestrictedCashAndMarketableSecurities	36232000	USD
CY2012Q2	ofc	Restricted Cash And Marketable Securities RestrictedCashAndMarketableSecurities	22632000	USD
	ofc	Revenues From Real Estate Operations Received RevenuesFromRealEstateOperationsReceived	233541000	USD
	ofc	Revenues From Real Estate Operations Received RevenuesFromRealEstateOperationsReceived	248742000	USD
	ofc	Scheduled Principal Amortization Repayments Of Long Term Debt ScheduledPrincipalAmortizationRepaymentsOfLongTermDebt	6303000	USD
	ofc	Scheduled Principal Amortization Repayments Of Long Term Debt ScheduledPrincipalAmortizationRepaymentsOfLongTermDebt	7421000	USD
	ofc	Segment Reporting Direct Costs Of Leased And Rented Property Or Equipment SegmentReportingDirectCostsOfLeasedAndRentedPropertyOrEquipment	94825000	USD
	ofc	Segment Reporting Direct Costs Of Leased And Rented Property Or Equipment SegmentReportingDirectCostsOfLeasedAndRentedPropertyOrEquipment	93546000	USD
CY2011Q2	ofc	Segment Reporting Direct Costs Of Leased And Rented Property Or Equipment SegmentReportingDirectCostsOfLeasedAndRentedPropertyOrEquipment	44673000	USD
CY2012Q2	ofc	Segment Reporting Direct Costs Of Leased And Rented Property Or Equipment SegmentReportingDirectCostsOfLeasedAndRentedPropertyOrEquipment	45159000	USD
	ofc	Segment Reporting Operating Income SegmentReportingOperatingIncome	148422000	USD
CY2011Q2	ofc	Segment Reporting Operating Income SegmentReportingOperatingIncome	76133000	USD
CY2012Q2	ofc	Segment Reporting Operating Income SegmentReportingOperatingIncome	78809000	USD
	ofc	Segment Reporting Operating Income SegmentReportingOperatingIncome	155726000	USD
	ofc	Segment Reporting Transfers From Non Operating Properties SegmentReportingTransfersFromNonOperatingProperties	101202000	USD
CY2012Q2	ofc	Segment Reporting Transfers From Non Operating Properties SegmentReportingTransfersFromNonOperatingProperties	66371000	USD
CY2011Q2	ofc	Segment Reporting Transfers From Non Operating Properties SegmentReportingTransfersFromNonOperatingProperties	15954000	USD
	ofc	Segment Reporting Transfers From Non Operating Properties SegmentReportingTransfersFromNonOperatingProperties	45211000	USD
	ofc	Share Based Compensation Recognized ShareBasedCompensationRecognized	7181000	USD
	ofc	Share Based Compensation Recognized ShareBasedCompensationRecognized	6358000	USD
CY2010Q3	ofc	Tax Incremental Financing Bonds Amount Issued By Anne Arundel County Maryland TaxIncrementalFinancingBondsAmountIssuedByAnneArundelCountyMaryland	30000000	USD
	ofc	Tenant Improvements On Operating Properties TenantImprovementsOnOperatingProperties	13797000	USD
	ofc	Tenant Improvements On Operating Properties TenantImprovementsOnOperatingProperties	20721000	USD
	ofc	Tenant Reimbursements And Other Real Estate Operations Revenue TenantReimbursementsAndOtherRealEstateOperationsRevenue	44073000	USD
CY2011Q2	ofc	Tenant Reimbursements And Other Real Estate Operations Revenue TenantReimbursementsAndOtherRealEstateOperationsRevenue	18682000	USD
CY2012Q2	ofc	Tenant Reimbursements And Other Real Estate Operations Revenue TenantReimbursementsAndOtherRealEstateOperationsRevenue	21889000	USD
	ofc	Tenant Reimbursements And Other Real Estate Operations Revenue TenantReimbursementsAndOtherRealEstateOperationsRevenue	40101000	USD
	dei	Amendment Flag AmendmentFlag	false
	dei	Current Fiscal Year End Date CurrentFiscalYearEndDate	--12-31
	dei	Document Fiscal Period Focus DocumentFiscalPeriodFocus	Q2
	dei	Document Fiscal Year Focus DocumentFiscalYearFocus	2012
	dei	Document Period End Date DocumentPeriodEndDate	2012-06-30
	dei	Document Type DocumentType	10-Q
	dei	Entity Central Index Key EntityCentralIndexKey	0000860546
CY2012Q3	dei	Entity Common Stock Shares Outstanding EntityCommonStockSharesOutstanding	72089752	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
0001445305-12-002318-index-headers.html	Edgar Link	pending
0001445305-12-002318-index.html	Edgar Link	pending
0001445305-12-002318.txt	Edgar Link	pending
0001445305-12-002318-xbrl.zip	Edgar Link	pending
copt630201210q.htm	Edgar Link	pending
copt6302012ex311.htm	Edgar Link	pending
copt6302012ex312.htm	Edgar Link	pending
copt6302012ex321.htm	Edgar Link	pending
copt6302012ex322.htm	Edgar Link	pending
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report.css	Edgar Link	pending
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$CDP
COPT Defense Properties Stock $cdp

2012 Q2 Form 10-Q Financial Statement

#000144530512002318 Filed on July 27, 2012

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$CDP COPT Defense Properties Stock $cdp

2012 Q2 Form 10-Q Financial Statement

#000144530512002318 Filed on July 27, 2012

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$CDP
COPT Defense Properties Stock $cdp