$CDP
COPT Defense Properties Stock $cdp

$cdp Overview Financials Valuation SEC Filings Company Website

2020 Q4 Form 10-Q Financial Statement

#000086054620000039 Filed on October 30, 2020

Income Statement

Concept	2020 Q4	2020 Q3	2019 Q3
Revenue	$156.6M	$148.8M	$159.4M
YoY Change	-0.75%	-6.67%	16.02%
Cost Of Revenue	$74.70M	$19.22M	$27.80M
YoY Change	-1.06%	-30.87%	245.02%
Gross Profit	$89.30M	$129.6M	$131.6M
YoY Change	8.51%	-1.56%	1.76%
Gross Profit Margin	57.02%	87.08%	82.56%
Selling, General & Admin	$10.80M	$7.467M	$7.929M
YoY Change	11.34%	-5.83%	14.93%
% of Gross Profit	12.09%	5.76%	6.02%
Research & Development	$1.000M	$1.100M	$1.000M
YoY Change	-23.08%	10.0%	-37.5%
% of Gross Profit	1.12%	0.85%	0.76%
Depreciation & Amortization	$37.10M	$35.80M	$35.20M
YoY Change	11.75%	1.7%	1.44%
% of Gross Profit	41.55%	27.63%	26.74%
Operating Expenses	$48.40M	$7.467M	$7.929M
YoY Change	10.5%	-5.83%	14.93%
Operating Profit	$40.90M	$122.1M	$123.7M
YoY Change	6.23%	-1.28%	231.17%
Interest Expense	-$13.40M	$17.15M	$17.13M
YoY Change	-6.94%	0.15%	-198.99%
% of Operating Profit	-32.76%	14.05%	13.84%
Other Income/Expense, Net	$800.0K	$1.500M
YoY Change
Pretax Income	$83.80M	-$31.80M	$22.72M
YoY Change	87.05%	-239.98%	15.58%
Income Tax	$300.0K	$16.00K	-$131.0K
% Of Pretax Income	0.36%		-0.58%
Net Earnings	$81.67M	-$31.85M	$21.26M
YoY Change	81.98%	-249.81%	13.69%
Net Earnings / Revenue	52.15%	-21.4%	13.33%
Basic Earnings Per Share	$0.73	-$0.29	$0.19
Diluted Earnings Per Share	$0.73	-$0.29	$0.19
COMMON SHARES
Basic Shares Outstanding	112.2M shares	111.8M shares	111.6M shares
Diluted Shares Outstanding		111.8M shares	111.9M shares

Balance Sheet

Concept	2020 Q4	2020 Q3	2019 Q3
SHORT-TERM ASSETS
Cash & Short-Term Investments	$18.40M	$11.50M	$34.00M
YoY Change	25.17%	-66.18%	257.89%
Cash & Equivalents	$18.37M	$11.46M	$34.01M
Short-Term Investments
Other Short-Term Assets
YoY Change
Inventory			$61.70M
Prepaid Expenses
Receivables	$41.60M	$36.20M	$37.60M
Other Receivables	$0.00	$0.00	$0.00
Total Short-Term Assets	$60.00M	$47.70M	$133.3M
YoY Change	19.76%	-64.22%	88.01%
LONG-TERM ASSETS
Property, Plant & Equipment	$10.43M	$3.674B	$3.335B
YoY Change	-99.69%	10.18%	46950.94%
Goodwill
YoY Change
Intangibles	$19.25M	$22.43M	$29.45M
YoY Change	-29.73%	-23.84%	-37.42%
Long-Term Investments	$44.40M	$58.80M	$59.80M
YoY Change	-28.04%	-1.67%	20.32%
Other Assets	$86.40M	$95.20M	$90.70M
YoY Change	-0.23%	4.96%	5.1%
Total Long-Term Assets	$4.017B	$4.072B	$3.722B
YoY Change	5.59%	9.41%	3.98%
TOTAL ASSETS
Total Short-Term Assets	$60.00M	$47.70M	$133.3M
Total Long-Term Assets	$4.017B	$4.072B	$3.722B
Total Assets	$4.077B	$4.120B	$3.855B
YoY Change	5.77%	6.87%	5.62%
SHORT-TERM LIABILITIES
YoY Change
Accounts Payable	$142.7M	$140.9M	$141.2M
YoY Change	-4.03%	-0.21%	56.54%
Accrued Expenses	$30.70M	$26.40M	$16.70M
YoY Change	77.46%	58.08%
Deferred Revenue
YoY Change
Short-Term Debt	$0.00	$0.00	$0.00
YoY Change
Long-Term Debt Due	$4.000M	$178.1M
YoY Change
Total Short-Term Liabilities	$242.1M	$407.0M	$217.2M
YoY Change	4.85%	87.38%	51.04%
LONG-TERM LIABILITIES
Long-Term Debt	$2.083B	$2.004B	$1.864B
YoY Change	13.68%	7.51%	3.03%
Other Long-Term Liabilities	$32.80M	$36.60M	$50.00M
YoY Change	-23.0%	-26.8%	-20.26%
Total Long-Term Liabilities	$2.116B	$2.040B	$1.914B
YoY Change	12.85%	6.62%	2.25%
TOTAL LIABILITIES
Total Short-Term Liabilities	$242.1M	$407.0M	$217.2M
Total Long-Term Liabilities	$2.116B	$2.040B	$1.914B
Total Liabilities	$2.358B	$2.447B	$2.131B
YoY Change	11.97%	14.84%	5.73%
SHAREHOLDERS EQUITY
Retained Earnings
YoY Change
Common Stock	$1.122M	$1.122M	$1.121M
YoY Change	0.09%	0.09%	3.03%
Preferred Stock
YoY Change
Treasury Stock (at cost)
YoY Change
Treasury Stock Shares
Shareholders Equity	$1.661B	$1.609B	$1.656B
YoY Change
Total Liabilities & Shareholders Equity	$4.077B	$4.120B	$3.855B
YoY Change	5.77%	6.87%	5.62%

Cashflow Statement

Concept	2020 Q4	2020 Q3	2019 Q3
OPERATING ACTIVITIES
Net Income	$81.67M	-$31.85M	$21.26M
YoY Change	81.98%	-249.81%	13.69%
Depreciation, Depletion And Amortization	$37.10M	$35.80M	$35.20M
YoY Change	11.75%	1.7%	1.44%
Cash From Operating Activities	$79.40M	$22.50M	$45.20M
YoY Change	10.89%	-50.22%	10.24%
INVESTING ACTIVITIES
Capital Expenditures	-$73.30M	-$119.2M	-$103.9M
YoY Change	-28.77%	14.73%	97.9%
Acquisitions
YoY Change
Other Investing Activities	$143.7M	-$49.70M	$8.500M
YoY Change	94.45%	-684.71%	-350.0%
Cash From Investing Activities	$70.40M	-$168.9M	-$95.30M
YoY Change	-341.92%	77.23%	70.48%
FINANCING ACTIVITIES
Cash Dividend Paid
YoY Change
Common Stock Issuance & Retirement, Net
YoY Change
Debt Paid & Issued, Net
YoY Change
Cash From Financing Activities	-142.4M	135.2M	36.80M
YoY Change	130.42%	267.39%	140.52%
NET CHANGE
Cash From Operating Activities	79.40M	22.50M	45.20M
Cash From Investing Activities	70.40M	-168.9M	-95.30M
Cash From Financing Activities	-142.4M	135.2M	36.80M
Net Change In Cash	7.400M	-11.20M	-13.30M
YoY Change	-138.34%	-15.79%	-3425.0%
FREE CASH FLOW
Cash From Operating Activities	$79.40M	$22.50M	$45.20M
Capital Expenditures	-$73.30M	-$119.2M	-$103.9M
Free Cash Flow	$152.7M	$141.7M	$149.1M
YoY Change	-12.49%	-4.96%	59.47%

Facts In Submission

Frame	Concept Type	Concept / XBRL Key	Value	Unit
	dei	Entity Central Index Key EntityCentralIndexKey	0000860546
	dei	Current Fiscal Year End Date CurrentFiscalYearEndDate	--12-31
	dei	Document Fiscal Year Focus DocumentFiscalYearFocus	2020
	dei	Document Fiscal Period Focus DocumentFiscalPeriodFocus	Q3
	dei	Amendment Flag AmendmentFlag	false
	dei	Entity Address Address Line1 EntityAddressAddressLine1	6711 Columbia Gateway Drive
	dei	Entity Address Address Line2 EntityAddressAddressLine2	Suite 300
	dei	Entity Address City Or Town EntityAddressCityOrTown	Columbia
	dei	Entity Address State Or Province EntityAddressStateOrProvince	MD
	dei	Document Type DocumentType	10-Q
	dei	Document Quarterly Report DocumentQuarterlyReport	true
	dei	Document Period End Date DocumentPeriodEndDate	2020-09-30
	dei	Document Transition Report DocumentTransitionReport	false
	dei	Entity File Number EntityFileNumber	1-14023
	dei	Entity Registrant Name EntityRegistrantName	CORPORATE OFFICE PROPERTIES TRUST
	dei	Entity Incorporation State Country Code EntityIncorporationStateCountryCode	MD
	dei	Entity Tax Identification Number EntityTaxIdentificationNumber	23-2947217
	dei	Entity Address Address Line1 EntityAddressAddressLine1	6711 Columbia Gateway Drive
	dei	Entity Address Address Line2 EntityAddressAddressLine2	Suite 300
	dei	Entity Address City Or Town EntityAddressCityOrTown	Columbia
	dei	Entity Address State Or Province EntityAddressStateOrProvince	MD
	dei	Entity Address Postal Zip Code EntityAddressPostalZipCode	21046
	dei	City Area Code CityAreaCode	443
	dei	Local Phone Number LocalPhoneNumber	285-5400
	dei	Security12b Title Security12bTitle	Common Shares of beneficial interest, $0.01 par value
	dei	Trading Symbol TradingSymbol	OFC
	dei	Security Exchange Name SecurityExchangeName	NYSE
	dei	Entity Current Reporting Status EntityCurrentReportingStatus	Yes
	dei	Entity Interactive Data Current EntityInteractiveDataCurrent	Yes
	dei	Entity Filer Category EntityFilerCategory	Large Accelerated Filer
	dei	Entity Small Business EntitySmallBusiness	false
	dei	Entity Emerging Growth Company EntityEmergingGrowthCompany	false
	dei	Entity Shell Company EntityShellCompany	false
CY2020Q4	dei	Entity Common Stock Shares Outstanding EntityCommonStockSharesOutstanding	112175248	shares
CY2020Q3	us-gaap	Rental Properties RentalProperties	2999892000	USD
CY2019Q4	us-gaap	Rental Properties RentalProperties	2772647000	USD
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CY2019Q4	us-gaap	Development In Process DevelopmentInProcess	568239000	USD
CY2020Q3	us-gaap	Real Estate Investment Property Net RealEstateInvestmentPropertyNet	3586938000	USD
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CY2020Q3	us-gaap	Operating Lease Right Of Use Asset OperatingLeaseRightOfUseAsset	36442000	USD
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	us-gaap	Gain Loss On Derivative Instruments Net Pretax GainLossOnDerivativeInstrumentsNetPretax	0	USD
CY2020Q3	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	-31803000	USD
CY2019Q3	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	22719000	USD
	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	18052000	USD
	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	153807000	USD
CY2020Q3	us-gaap	Income Loss From Equity Method Investments IncomeLossFromEquityMethodInvestments	477000	USD
CY2019Q3	us-gaap	Income Loss From Equity Method Investments IncomeLossFromEquityMethodInvestments	396000	USD
	us-gaap	Income Loss From Equity Method Investments IncomeLossFromEquityMethodInvestments	1372000	USD
	us-gaap	Income Loss From Equity Method Investments IncomeLossFromEquityMethodInvestments	1207000	USD
CY2020Q3	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	16000	USD
CY2019Q3	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	-131000	USD
	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	95000	USD
	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	-113000	USD
CY2020Q3	us-gaap	Profit Loss ProfitLoss	-31342000	USD
CY2019Q3	us-gaap	Profit Loss ProfitLoss	23246000	USD
	us-gaap	Profit Loss ProfitLoss	19329000	USD
	us-gaap	Profit Loss ProfitLoss	155127000	USD
CY2020Q3	us-gaap	Noncontrolling Interest In Net Income Loss Operating Partnerships Nonredeemable NoncontrollingInterestInNetIncomeLossOperatingPartnershipsNonredeemable	-386000	USD
CY2019Q3	us-gaap	Noncontrolling Interest In Net Income Loss Operating Partnerships Nonredeemable NoncontrollingInterestInNetIncomeLossOperatingPartnershipsNonredeemable	267000	USD
	us-gaap	Noncontrolling Interest In Net Income Loss Operating Partnerships Nonredeemable NoncontrollingInterestInNetIncomeLossOperatingPartnershipsNonredeemable	185000	USD
	us-gaap	Noncontrolling Interest In Net Income Loss Operating Partnerships Nonredeemable NoncontrollingInterestInNetIncomeLossOperatingPartnershipsNonredeemable	1863000	USD
CY2020Q3	us-gaap	Noncontrolling Interest In Net Income Loss Preferred Unit Holders Nonredeemable NoncontrollingInterestInNetIncomeLossPreferredUnitHoldersNonredeemable	77000	USD
CY2019Q3	us-gaap	Noncontrolling Interest In Net Income Loss Preferred Unit Holders Nonredeemable NoncontrollingInterestInNetIncomeLossPreferredUnitHoldersNonredeemable	157000	USD
	us-gaap	Noncontrolling Interest In Net Income Loss Preferred Unit Holders Nonredeemable NoncontrollingInterestInNetIncomeLossPreferredUnitHoldersNonredeemable	231000	USD
	us-gaap	Noncontrolling Interest In Net Income Loss Preferred Unit Holders Nonredeemable NoncontrollingInterestInNetIncomeLossPreferredUnitHoldersNonredeemable	487000	USD
CY2020Q3	ofc	Minority Interest In Net Income Loss Other Including Joint Ventures Minority Interests MinorityInterestInNetIncomeLossOtherIncludingJointVenturesMinorityInterests	812000	USD
CY2019Q3	ofc	Minority Interest In Net Income Loss Other Including Joint Ventures Minority Interests MinorityInterestInNetIncomeLossOtherIncludingJointVenturesMinorityInterests	1565000	USD
	ofc	Minority Interest In Net Income Loss Other Including Joint Ventures Minority Interests MinorityInterestInNetIncomeLossOtherIncludingJointVenturesMinorityInterests	3207000	USD
	ofc	Minority Interest In Net Income Loss Other Including Joint Ventures Minority Interests MinorityInterestInNetIncomeLossOtherIncludingJointVenturesMinorityInterests	3870000	USD
CY2020Q3	ofc	Net Income Loss Available To Common Stockholders Including Participating Securities NetIncomeLossAvailableToCommonStockholdersIncludingParticipatingSecurities	-31845000	USD
CY2019Q3	ofc	Net Income Loss Available To Common Stockholders Including Participating Securities NetIncomeLossAvailableToCommonStockholdersIncludingParticipatingSecurities	21257000	USD
	ofc	Net Income Loss Available To Common Stockholders Including Participating Securities NetIncomeLossAvailableToCommonStockholdersIncludingParticipatingSecurities	15706000	USD
	ofc	Net Income Loss Available To Common Stockholders Including Participating Securities NetIncomeLossAvailableToCommonStockholdersIncludingParticipatingSecurities	148907000	USD
CY2020Q3	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	-0.29
CY2019Q3	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.19
	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.14
	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.34
CY2020Q3	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	-0.29
CY2019Q3	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.19
	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.14
	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.33
CY2020Q3	us-gaap	Profit Loss ProfitLoss	-31342000	USD
CY2019Q3	us-gaap	Profit Loss ProfitLoss	23246000	USD
	us-gaap	Profit Loss ProfitLoss	19329000	USD
	us-gaap	Profit Loss ProfitLoss	155127000	USD
CY2020Q3	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Before Reclassification After Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAfterTax	1428000	USD
CY2019Q3	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Before Reclassification After Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAfterTax	-11047000	USD
	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Before Reclassification After Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAfterTax	-39592000	USD
	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Before Reclassification After Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAfterTax	-33437000	USD
CY2020Q3	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Reclassification After Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossReclassificationAfterTax	-1342000	USD
CY2019Q3	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Reclassification After Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossReclassificationAfterTax	307000	USD
	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Reclassification After Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossReclassificationAfterTax	-2408000	USD
	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Reclassification After Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossReclassificationAfterTax	1434000	USD
CY2020Q3	ofc	Other Comprehensive Income Loss Cash Flow Hedge Reclassification For Discontinuanceafter Tax OtherComprehensiveIncomeLossCashFlowHedgeReclassificationForDiscontinuanceafterTax	-51865000	USD
CY2019Q3	ofc	Other Comprehensive Income Loss Cash Flow Hedge Reclassification For Discontinuanceafter Tax OtherComprehensiveIncomeLossCashFlowHedgeReclassificationForDiscontinuanceafterTax	0	USD
	ofc	Other Comprehensive Income Loss Cash Flow Hedge Reclassification For Discontinuanceafter Tax OtherComprehensiveIncomeLossCashFlowHedgeReclassificationForDiscontinuanceafterTax	-51865000	USD
	ofc	Other Comprehensive Income Loss Cash Flow Hedge Reclassification For Discontinuanceafter Tax OtherComprehensiveIncomeLossCashFlowHedgeReclassificationForDiscontinuanceafterTax	0	USD
CY2020Q3	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	54635000	USD
CY2019Q3	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	-11354000	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	14681000	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	-34871000	USD
CY2020Q3	us-gaap	Comprehensive Income Net Of Tax Including Portion Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest	23293000	USD
CY2019Q3	us-gaap	Comprehensive Income Net Of Tax Including Portion Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest	11892000	USD
	us-gaap	Comprehensive Income Net Of Tax Including Portion Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest	34010000	USD
	us-gaap	Comprehensive Income Net Of Tax Including Portion Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest	120256000	USD
CY2020Q3	us-gaap	Comprehensive Income Net Of Tax Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxAttributableToNoncontrollingInterest	1173000	USD
CY2019Q3	us-gaap	Comprehensive Income Net Of Tax Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxAttributableToNoncontrollingInterest	1750000	USD
	us-gaap	Comprehensive Income Net Of Tax Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxAttributableToNoncontrollingInterest	3408000	USD
	us-gaap	Comprehensive Income Net Of Tax Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxAttributableToNoncontrollingInterest	5691000	USD
CY2020Q3	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	22120000	USD
CY2019Q3	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	10142000	USD
	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	30602000	USD
	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	114565000	USD
CY2019Q2	us-gaap	Common Stock Shares Outstanding CommonStockSharesOutstanding	111949887	shares
CY2019Q2	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	1719111000	USD
CY2019Q3	us-gaap	Stock Issued During Period Shares Conversion Of Units StockIssuedDuringPeriodSharesConversionOfUnits	97539	shares
CY2019Q3	us-gaap	Stock Issued During Period Value Conversion Of Units StockIssuedDuringPeriodValueConversionOfUnits	0	USD
CY2019Q3	us-gaap	Partners Capital Account Redemptions PartnersCapitalAccountRedemptions	24000	USD
CY2019Q3	us-gaap	Stock Issued During Period Shares Share Based Compensation StockIssuedDuringPeriodSharesShareBasedCompensation	11749	shares
CY2019Q3	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	1895000	USD
CY2019Q3	us-gaap	Stock Repurchased During Period Value StockRepurchasedDuringPeriodValue	53000	USD
CY2019Q3	us-gaap	Noncontrolling Interest Increase From Subsidiary Equity Issuance NoncontrollingInterestIncreaseFromSubsidiaryEquityIssuance	0	USD
CY2019Q3	ofc	Comprehensive Income Loss Net Of Tax After Redeemable Noncontrolling Interest Adjustments ComprehensiveIncomeLossNetOfTaxAfterRedeemableNoncontrollingInterestAdjustments	10707000	USD
CY2019Q3	us-gaap	Dividends Dividends	30825000	USD
CY2019Q3	ofc	Minority Interest Decrease From Distributions To Operating Partnership Noncontrolling Interest Holders MinorityInterestDecreaseFromDistributionsToOperatingPartnershipNoncontrollingInterestHolders	517000	USD
CY2019Q3	ofc	Minority Interest Decrease From Distributions Including Joint Ventures MinorityInterestDecreaseFromDistributionsIncludingJointVentures	5878000	USD
CY2019Q3	ofc	Adjustmentto Equityto Arriveat Fair Valueof Redeemable Noncontrolling Interest AdjustmenttoEquitytoArriveatFairValueofRedeemableNoncontrollingInterest	1531000	USD
CY2019Q3	us-gaap	Common Stock Shares Outstanding CommonStockSharesOutstanding	112059175	shares
CY2019Q3	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	1695947000	USD
CY2020Q2	us-gaap	Common Stock Shares Outstanding CommonStockSharesOutstanding	112183192	shares
CY2020Q2	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	1656924000	USD
CY2020Q3	us-gaap	Stock Issued During Period Shares Share Based Compensation StockIssuedDuringPeriodSharesShareBasedCompensation	-7504	shares
CY2020Q3	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	1784000	USD
CY2020Q3	us-gaap	Stock Repurchased During Period Value StockRepurchasedDuringPeriodValue	57000	USD
CY2020Q3	us-gaap	Noncontrolling Interest Increase From Subsidiary Equity Issuance NoncontrollingInterestIncreaseFromSubsidiaryEquityIssuance	0	USD
CY2018Q4	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	1627048000	USD
CY2020Q3	ofc	Comprehensive Income Loss Net Of Tax After Redeemable Noncontrolling Interest Adjustments ComprehensiveIncomeLossNetOfTaxAfterRedeemableNoncontrollingInterestAdjustments	22653000	USD
CY2020Q3	us-gaap	Dividends Dividends	30843000	USD
CY2020Q3	ofc	Minority Interest Decrease From Distributions To Operating Partnership Noncontrolling Interest Holders MinorityInterestDecreaseFromDistributionsToOperatingPartnershipNoncontrollingInterestHolders	444000	USD
CY2020Q3	ofc	Minority Interest Decrease From Distributions Including Joint Ventures MinorityInterestDecreaseFromDistributionsIncludingJointVentures	7000	USD
CY2020Q3	ofc	Adjustmentto Equityto Arriveat Fair Valueof Redeemable Noncontrolling Interest AdjustmenttoEquitytoArriveatFairValueofRedeemableNoncontrollingInterest	-374000	USD
CY2020Q3	us-gaap	Common Stock Shares Outstanding CommonStockSharesOutstanding	112175688	shares
CY2020Q3	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	1649636000	USD
CY2018Q4	us-gaap	Common Stock Shares Outstanding CommonStockSharesOutstanding	110241868	shares
	us-gaap	Stock Issued During Period Shares Conversion Of Units StockIssuedDuringPeriodSharesConversionOfUnits	103039	shares
	us-gaap	Stock Issued During Period Value Conversion Of Units StockIssuedDuringPeriodValueConversionOfUnits	0	USD
	us-gaap	Partners Capital Account Redemptions PartnersCapitalAccountRedemptions	25000	USD
	us-gaap	Stock Issued During Period Shares Share Based Compensation StockIssuedDuringPeriodSharesShareBasedCompensation	100181	shares
	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	5530000	USD
	us-gaap	Stock Repurchased During Period Value StockRepurchasedDuringPeriodValue	1973000	USD
	us-gaap	Noncontrolling Interest Increase From Subsidiary Equity Issuance NoncontrollingInterestIncreaseFromSubsidiaryEquityIssuance	0	USD
	ofc	Minority Interest Decrease From Distributions Including Joint Ventures MinorityInterestDecreaseFromDistributionsIncludingJointVentures	5886000	USD
	ofc	Adjustmentto Equityto Arriveat Fair Valueof Redeemable Noncontrolling Interest AdjustmenttoEquitytoArriveatFairValueofRedeemableNoncontrollingInterest	-1344000	USD
	ofc	Comprehensive Income Loss Net Of Tax After Redeemable Noncontrolling Interest Adjustments ComprehensiveIncomeLossNetOfTaxAfterRedeemableNoncontrollingInterestAdjustments	117527000	USD
	us-gaap	Dividends Dividends	92334000	USD
	ofc	Minority Interest Decrease From Distributions To Operating Partnership Noncontrolling Interest Holders MinorityInterestDecreaseFromDistributionsToOperatingPartnershipNoncontrollingInterestHolders	1620000	USD
	ofc	Minority Interest Increase From Contributions Including Joint Ventures MinorityInterestIncreaseFromContributionsIncludingJointVentures	2570000	USD
CY2019Q3	us-gaap	Common Stock Shares Outstanding CommonStockSharesOutstanding	112059175	shares
CY2019Q3	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	1695947000	USD
CY2019Q4	us-gaap	Common Stock Shares Outstanding CommonStockSharesOutstanding	112068705	shares
CY2019Q4	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	1719245000	USD
	us-gaap	Stock Issued During Period Shares Conversion Of Units StockIssuedDuringPeriodSharesConversionOfUnits	12009	shares
	us-gaap	Stock Issued During Period Value Conversion Of Units StockIssuedDuringPeriodValueConversionOfUnits	0	USD
	us-gaap	Stock Issued During Period Shares Share Based Compensation StockIssuedDuringPeriodSharesShareBasedCompensation	94974	shares
	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	4730000	USD
	us-gaap	Stock Repurchased During Period Value StockRepurchasedDuringPeriodValue	1629000	USD
	us-gaap	Noncontrolling Interest Increase From Subsidiary Equity Issuance NoncontrollingInterestIncreaseFromSubsidiaryEquityIssuance	0	USD
	ofc	Comprehensive Income Loss Net Of Tax After Redeemable Noncontrolling Interest Adjustments ComprehensiveIncomeLossNetOfTaxAfterRedeemableNoncontrollingInterestAdjustments	31295000	USD
	us-gaap	Dividends Dividends	92537000	USD
	ofc	Minority Interest Decrease From Distributions To Operating Partnership Noncontrolling Interest Holders MinorityInterestDecreaseFromDistributionsToOperatingPartnershipNoncontrollingInterestHolders	1306000	USD
	ofc	Minority Interest Increase From Contributions Including Joint Ventures MinorityInterestIncreaseFromContributionsIncludingJointVentures	112000	USD
	ofc	Minority Interest Decrease From Distributions Including Joint Ventures MinorityInterestDecreaseFromDistributionsIncludingJointVentures	22000	USD
	ofc	Adjustmentto Equityto Arriveat Fair Valueof Redeemable Noncontrolling Interest AdjustmenttoEquitytoArriveatFairValueofRedeemableNoncontrollingInterest	-4711000	USD
CY2020Q3	us-gaap	Common Stock Shares Outstanding CommonStockSharesOutstanding	112175688	shares
CY2020Q3	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	1649636000	USD
	ofc	Revenues From Real Estate Operations Received RevenuesFromRealEstateOperationsReceived	394094000	USD
	ofc	Revenues From Real Estate Operations Received RevenuesFromRealEstateOperationsReceived	391758000	USD
	ofc	Construction Contract And Other Service Revenues Received ConstructionContractAndOtherServiceRevenuesReceived	53911000	USD
	ofc	Construction Contract And Other Service Revenues Received ConstructionContractAndOtherServiceRevenuesReceived	65813000	USD
	ofc	Property Operating Expenses Paid PropertyOperatingExpensesPaid	159007000	USD
	ofc	Property Operating Expenses Paid PropertyOperatingExpensesPaid	151478000	USD
	ofc	Construction Contract And Other Service Expenses Paid ConstructionContractAndOtherServiceExpensesPaid	45686000	USD
	ofc	Construction Contract And Other Service Expenses Paid ConstructionContractAndOtherServiceExpensesPaid	68599000	USD
	ofc	Generaland Administrative Leasing Business Developmentand Land Carry Paid GeneralandAdministrativeLeasingBusinessDevelopmentandLandCarryPaid	24408000	USD
	ofc	Generaland Administrative Leasing Business Developmentand Land Carry Paid GeneralandAdministrativeLeasingBusinessDevelopmentandLandCarryPaid	23806000	USD
	us-gaap	Interest Paid Net InterestPaidNet	49693000	USD
	us-gaap	Interest Paid Net InterestPaidNet	52818000	USD
	ofc	Paymentsof Lease Incentives PaymentsofLeaseIncentives	12634000	USD
	ofc	Paymentsof Lease Incentives PaymentsofLeaseIncentives	6366000	USD
	us-gaap	Other Operating Activities Cash Flow Statement OtherOperatingActivitiesCashFlowStatement	2464000	USD
	us-gaap	Other Operating Activities Cash Flow Statement OtherOperatingActivitiesCashFlowStatement	2533000	USD
	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	159041000	USD
	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	157037000	USD
	us-gaap	Payments To Develop Real Estate Assets PaymentsToDevelopRealEstateAssets	284416000	USD
	us-gaap	Payments To Develop Real Estate Assets PaymentsToDevelopRealEstateAssets	308997000	USD
	us-gaap	Payments For Tenant Improvements PaymentsForTenantImprovements	23377000	USD
	us-gaap	Payments For Tenant Improvements PaymentsForTenantImprovements	16466000	USD
	us-gaap	Payments For Capital Improvements PaymentsForCapitalImprovements	24797000	USD
	us-gaap	Payments For Capital Improvements PaymentsForCapitalImprovements	14497000	USD
	us-gaap	Proceeds From Equity Method Investment Dividends Or Distributions Return Of Capital ProceedsFromEquityMethodInvestmentDividendsOrDistributionsReturnOfCapital	0	USD
	us-gaap	Proceeds From Equity Method Investment Dividends Or Distributions Return Of Capital ProceedsFromEquityMethodInvestmentDividendsOrDistributionsReturnOfCapital	129783000	USD
	us-gaap	Proceeds From Sale Of Real Estate Heldforinvestment ProceedsFromSaleOfRealEstateHeldforinvestment	0	USD
	us-gaap	Proceeds From Sale Of Real Estate Heldforinvestment ProceedsFromSaleOfRealEstateHeldforinvestment	107440000	USD
	us-gaap	Proceeds From Distributions Received From Real Estate Partnerships ProceedsFromDistributionsReceivedFromRealEstatePartnerships	2287000	USD
	us-gaap	Proceeds From Distributions Received From Real Estate Partnerships ProceedsFromDistributionsReceivedFromRealEstatePartnerships	16937000	USD
	us-gaap	Payments To Acquire Notes Receivable PaymentsToAcquireNotesReceivable	258000	USD
	us-gaap	Payments To Acquire Notes Receivable PaymentsToAcquireNotesReceivable	11169000	USD
	us-gaap	Payments For Leasing Costs PaymentsForLeasingCosts	12455000	USD
	us-gaap	Payments For Leasing Costs PaymentsForLeasingCosts	13502000	USD
	us-gaap	Payments For Derivative Instrument Investing Activities PaymentsForDerivativeInstrumentInvestingActivities	53130000	USD
	us-gaap	Payments For Derivative Instrument Investing Activities PaymentsForDerivativeInstrumentInvestingActivities	0	USD
	us-gaap	Payments For Proceeds From Other Investing Activities PaymentsForProceedsFromOtherInvestingActivities	63000	USD
	us-gaap	Payments For Proceeds From Other Investing Activities PaymentsForProceedsFromOtherInvestingActivities	-1558000	USD
	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-396209000	USD
	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-108913000	USD
	us-gaap	Proceeds From Long Term Lines Of Credit ProceedsFromLongTermLinesOfCredit	409000000	USD
	us-gaap	Proceeds From Long Term Lines Of Credit ProceedsFromLongTermLinesOfCredit	349000000	USD
	us-gaap	Proceeds From Issuance Of Senior Long Term Debt ProceedsFromIssuanceOfSeniorLongTermDebt	395264000	USD
	us-gaap	Proceeds From Issuance Of Senior Long Term Debt ProceedsFromIssuanceOfSeniorLongTermDebt	0	USD
	us-gaap	Proceeds From Issuance Of Other Long Term Debt ProceedsFromIssuanceOfOtherLongTermDebt	199088000	USD
	us-gaap	Proceeds From Issuance Of Other Long Term Debt ProceedsFromIssuanceOfOtherLongTermDebt	32002000	USD
	us-gaap	Repayments Of Long Term Lines Of Credit RepaymentsOfLongTermLinesOfCredit	529000000	USD
	us-gaap	Repayments Of Long Term Lines Of Credit RepaymentsOfLongTermLinesOfCredit	342000000	USD
	us-gaap	Repayments Of Senior Debt RepaymentsOfSeniorDebt	122948000	USD
	us-gaap	Repayments Of Senior Debt RepaymentsOfSeniorDebt	0	USD
	ofc	Scheduled Principal Amortization Repayments Of Long Term Debt ScheduledPrincipalAmortizationRepaymentsOfLongTermDebt	3077000	USD
	ofc	Scheduled Principal Amortization Repayments Of Long Term Debt ScheduledPrincipalAmortizationRepaymentsOfLongTermDebt	3300000	USD
	us-gaap	Payments Of Financing Costs PaymentsOfFinancingCosts	2161000	USD
	us-gaap	Payments Of Financing Costs PaymentsOfFinancingCosts	405000	USD
	us-gaap	Proceeds From Issuance Of Common Stock ProceedsFromIssuanceOfCommonStock	0	USD
	us-gaap	Proceeds From Issuance Of Common Stock ProceedsFromIssuanceOfCommonStock	46415000	USD
	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	92512000	USD
	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	91835000	USD
	us-gaap	Payments Of Dividends Minority Interest PaymentsOfDividendsMinorityInterest	1303000	USD
	us-gaap	Payments Of Dividends Minority Interest PaymentsOfDividendsMinorityInterest	1661000	USD
	ofc	Payments Of Ordinary Dividends Noncontrolling Interest In Other Consolidated Entities PaymentsOfOrdinaryDividendsNoncontrollingInterestInOtherConsolidatedEntities	15000	USD
	ofc	Payments Of Ordinary Dividends Noncontrolling Interest In Other Consolidated Entities PaymentsOfOrdinaryDividendsNoncontrollingInterestInOtherConsolidatedEntities	5882000	USD
	ofc	Paymentsof Distributions Redeemable Noncontrolling Interest PaymentsofDistributionsRedeemableNoncontrollingInterest	13515000	USD
	ofc	Paymentsof Distributions Redeemable Noncontrolling Interest PaymentsofDistributionsRedeemableNoncontrollingInterest	984000	USD
	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	1629000	USD
	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	1973000	USD
	us-gaap	Payments Of Debt Extinguishment Costs PaymentsOfDebtExtinguishmentCosts	3037000	USD
	us-gaap	Payments Of Debt Extinguishment Costs PaymentsOfDebtExtinguishmentCosts	0	USD
	us-gaap	Proceeds From Payments For Other Financing Activities ProceedsFromPaymentsForOtherFinancingActivities	-442000	USD
	us-gaap	Proceeds From Payments For Other Financing Activities ProceedsFromPaymentsForOtherFinancingActivities	-1944000	USD
	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	233713000	USD
	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	-22567000	USD
	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	-3455000	USD
	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	25557000	USD
CY2019Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	18130000	USD
CY2018Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	11950000	USD
CY2020Q3	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	14675000	USD
CY2019Q3	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	37507000	USD
	us-gaap	Profit Loss ProfitLoss	19329000	USD
	us-gaap	Profit Loss ProfitLoss	155127000	USD
	us-gaap	Depreciation Depletion And Amortization DepreciationDepletionAndAmortization	102864000	USD
	us-gaap	Depreciation Depletion And Amortization DepreciationDepletionAndAmortization	105686000	USD
	us-gaap	Asset Impairment Charges AssetImpairmentCharges	1530000	USD
	us-gaap	Asset Impairment Charges AssetImpairmentCharges	327000	USD
	us-gaap	Amortization Of Financing Costs And Discounts AmortizationOfFinancingCostsAndDiscounts	3104000	USD
	us-gaap	Amortization Of Financing Costs And Discounts AmortizationOfFinancingCostsAndDiscounts	2716000	USD
	us-gaap	Straight Line Rent StraightLineRent	3560000	USD
	us-gaap	Straight Line Rent StraightLineRent	4184000	USD
	us-gaap	Gain Loss On Sale Of Properties GainLossOnSaleOfProperties	5000	USD
	us-gaap	Gain Loss On Sale Of Properties GainLossOnSaleOfProperties	84469000	USD
	us-gaap	Share Based Compensation ShareBasedCompensation	4753000	USD
	us-gaap	Share Based Compensation ShareBasedCompensation	4979000	USD
	us-gaap	Gains Losses On Extinguishment Of Debt GainsLossesOnExtinguishmentOfDebt	-3237000	USD
	us-gaap	Gains Losses On Extinguishment Of Debt GainsLossesOnExtinguishmentOfDebt	0	USD
	us-gaap	Derivative Gain Loss On Derivative Net DerivativeGainLossOnDerivativeNet	-53196000	USD
	us-gaap	Derivative Gain Loss On Derivative Net DerivativeGainLossOnDerivativeNet	0	USD
	us-gaap	Other Noncash Income Expense OtherNoncashIncomeExpense	4184000	USD
	us-gaap	Other Noncash Income Expense OtherNoncashIncomeExpense	4296000	USD
	us-gaap	Increase Decrease In Accounts Receivable IncreaseDecreaseInAccountsReceivable	744000	USD
	us-gaap	Increase Decrease In Accounts Receivable IncreaseDecreaseInAccountsReceivable	9483000	USD
	us-gaap	Increase Decrease In Prepaid Deferred Expense And Other Assets IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets	13164000	USD
	us-gaap	Increase Decrease In Prepaid Deferred Expense And Other Assets IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets	26878000	USD
	us-gaap	Increase Decrease In Operating Liabilities IncreaseDecreaseInOperatingLiabilities	-3971000	USD
	us-gaap	Increase Decrease In Operating Liabilities IncreaseDecreaseInOperatingLiabilities	19616000	USD
	ofc	Increase Decrease In Advance Rent And Security Deposit Liability IncreaseDecreaseInAdvanceRentAndSecurityDepositLiability	-3344000	USD
	ofc	Increase Decrease In Advance Rent And Security Deposit Liability IncreaseDecreaseInAdvanceRentAndSecurityDepositLiability	-2104000	USD
	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	159041000	USD
	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	157037000	USD
CY2019Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	14733000	USD
CY2018Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	8066000	USD
CY2019Q4	us-gaap	Restricted Cash RestrictedCash	3397000	USD
CY2018Q4	us-gaap	Restricted Cash RestrictedCash	3884000	USD
CY2019Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	18130000	USD
CY2018Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	11950000	USD
CY2020Q3	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	11458000	USD
CY2019Q3	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	34005000	USD
CY2020Q3	us-gaap	Restricted Cash RestrictedCash	3217000	USD
CY2019Q3	us-gaap	Restricted Cash RestrictedCash	3502000	USD
CY2020Q3	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	14675000	USD
CY2019Q3	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	37507000	USD
	ofc	Increase Decrease In Accrued Capital Improvements Leasing And Other Investing Activity Costs IncreaseDecreaseInAccruedCapitalImprovementsLeasingAndOtherInvestingActivityCosts	-195000	USD
	ofc	Increase Decrease In Accrued Capital Improvements Leasing And Other Investing Activity Costs IncreaseDecreaseInAccruedCapitalImprovementsLeasingAndOtherInvestingActivityCosts	29457000	USD
	ofc	Rightof Use Asset Contributed By Noncontrolling Interest RightofUseAssetContributedByNoncontrollingInterest	0	USD
	ofc	Rightof Use Asset Contributed By Noncontrolling Interest RightofUseAssetContributedByNoncontrollingInterest	2570000	USD
	us-gaap	Right Of Use Asset Obtained In Exchange For Operating Lease Liability RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability	8955000	USD
	us-gaap	Right Of Use Asset Obtained In Exchange For Operating Lease Liability RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability	255000	USD
	ofc	Noncashor Part Noncash Disposition Decreasein Propertyin Connection With Partial Saleof Properties Net NoncashorPartNoncashDispositionDecreaseinPropertyinConnectionWithPartialSaleofPropertiesNet	0	USD
	ofc	Noncashor Part Noncash Disposition Decreasein Propertyin Connection With Partial Saleof Properties Net NoncashorPartNoncashDispositionDecreaseinPropertyinConnectionWithPartialSaleofPropertiesNet	99288000	USD
	ofc	Increasein Investmentin Unconsolidated Real Estate Joint Venturein Connection With Partial Saleof Properties IncreaseinInvestmentinUnconsolidatedRealEstateJointVentureinConnectionWithPartialSaleofProperties	0	USD
	ofc	Increasein Investmentin Unconsolidated Real Estate Joint Venturein Connection With Partial Saleof Properties IncreaseinInvestmentinUnconsolidatedRealEstateJointVentureinConnectionWithPartialSaleofProperties	26500000	USD
	ofc	Increase Decrease In Fair Value Of Derivatives Applied To Aocl And Noncontrolling Interests IncreaseDecreaseInFairValueOfDerivativesAppliedToAoclAndNoncontrollingInterests	-37183000	USD
	ofc	Increase Decrease In Fair Value Of Derivatives Applied To Aocl And Noncontrolling Interests IncreaseDecreaseInFairValueOfDerivativesAppliedToAoclAndNoncontrollingInterests	-34951000	USD
CY2020Q3	us-gaap	Dividends Payable Current And Noncurrent DividendsPayableCurrentAndNoncurrent	31307000	USD
CY2019Q3	us-gaap	Dividends Payable Current And Noncurrent DividendsPayableCurrentAndNoncurrent	31345000	USD
	ofc	Equity Change Stock Issued During Period Value Conversion Of Units EquityChangeStockIssuedDuringPeriodValueConversionOfUnits	182000	USD
	ofc	Equity Change Stock Issued During Period Value Conversion Of Units EquityChangeStockIssuedDuringPeriodValueConversionOfUnits	1556000	USD
	ofc	Equity Change Adjustments To Additional Paid In Capital Reallocation Of Minority Interest EquityChangeAdjustmentsToAdditionalPaidInCapitalReallocationOfMinorityInterest	-527000	USD
	ofc	Equity Change Adjustments To Additional Paid In Capital Reallocation Of Minority Interest EquityChangeAdjustmentsToAdditionalPaidInCapitalReallocationOfMinorityInterest	522000	USD
	us-gaap	Minority Interest Change In Redemption Value MinorityInterestChangeInRedemptionValue	4711000	USD
	us-gaap	Minority Interest Change In Redemption Value MinorityInterestChangeInRedemptionValue	1344000	USD
	us-gaap	Nature Of Operations NatureOfOperations	Organization<div><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"> </span></div><div style="text-indent:18pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Corporate Office Properties Trust (“COPT”) and subsidiaries (collectively, the “Company”) is a fully-integrated and self-managed real estate investment trust (“REIT”). Corporate Office Properties, L.P. (“COPLP”) and subsidiaries (collectively, the “Operating Partnership”) is the entity through which COPT, the sole general partner of COPLP, conducts almost all of its operations and owns almost all of its assets. Unless otherwise expressly stated or the context otherwise requires, “we”, “us” and “our” as used herein refer to each of the Company and the Operating Partnership. We own, manage, lease, develop and selectively acquire office and data center properties. The majority of our portfolio is in locations that support the United States Government (“USG”) and its contractors, most of whom are engaged in national security, defense and information technology (“IT”) related activities servicing what we believe are growing, durable, priority missions (“Defense/IT Locations”). We also own a portfolio of office properties located in select urban/urban-like submarkets in the Greater Washington, DC/Baltimore region with durable Class-A office fundamentals and characteristics (“Regional Office”). As of September 30, 2020, our properties included the following:</span></div><div style="padding-left:18pt"><span><br/></span></div><div style="padding-left:18pt;text-indent:-18pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">•</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:14.5pt">176 properties totaling 20.4 million square feet comprised of 15.9 million square feet in 151 office properties and 4.5 million square feet in 25 single-tenant data center shell properties (“data center shells”). We owned 15 of these data center shells through unconsolidated real estate joint ventures;</span></div><div style="padding-left:18pt;text-indent:-18pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">•</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:14.5pt">a wholesale data center with a critical load of 19.25 megawatts;</span></div><div style="padding-left:18pt;text-indent:-18pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">•</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:14.5pt">11 properties under development (ten office properties and one data center shell), including one partially-operational property, and expansion of one fully-operational property that we estimate will total approximately 1.6 million square feet upon completion; and</span></div><div style="padding-left:18pt;text-indent:-18pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">•</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:14.5pt">approximately 860 acres of land controlled for future development that we believe could be developed into approximately 11.0 million square feet and 43 acres of other land.</span></div><div><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"> </span></div><div><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">COPLP owns real estate directly and through subsidiary partnerships and limited liability companies (“LLCs”). In addition to owning real estate, COPLP also owns subsidiaries that provide real estate services such as property management, development and construction services primarily for our properties but also for third parties. Some of these services are performed by a taxable REIT subsidiary (“TRS”).</span></div><div style="text-indent:18pt"><span><br/></span></div><div style="text-indent:18pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Equity interests in COPLP are in the form of common and preferred units. As of September 30, 2020, COPT owned 98.6% of the outstanding COPLP common units (“common units”); the remaining common units and all of the outstanding COPLP preferred units (“preferred units”) were owned by third parties. Common units not owned by COPT carry certain redemption rights. The number of common units owned by COPT is equivalent to the number of outstanding common shares of beneficial interest (“common shares”) of COPT, and the entitlement of common units to quarterly distributions and payments in liquidation is substantially the same as that of COPT common shareholders. In the case of any series of preferred units held by COPT, there would be a series of preferred shares of beneficial interest (“preferred shares”) in COPT that is equivalent in number and carries substantially the same terms as such series of COPLP preferred units. </span></div><div style="text-indent:18pt"><span><br/></span></div><div style="text-indent:18pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">COPT’s common shares are publicly traded on the New York Stock Exchange (“NYSE”) under the ticker symbol “OFC”. </span></div><div style="text-indent:18pt"><span><br/></span></div><div style="text-indent:18pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Because COPLP is managed by COPT, and COPT conducts substantially all of its operations through COPLP, we refer to COPT’s executive officers as COPLP’s executive officers; similarly, although COPLP does not have a board of trustees, we refer to COPT’s Board of Trustees as COPLP’s Board of Trustees.</span></div>
	us-gaap	Prior Period Reclassification Adjustment Description PriorPeriodReclassificationAdjustmentDescription	<div><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">Reclassifications</span></div><div><span><br/></span></div><div style="text-indent:18pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">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.</span></div>
CY2019Q4	ofc	Off Balance Sheet Credit Loss Exposure Allowancefor Credit Loss OffBalanceSheetCreditLossExposureAllowanceforCreditLoss	0	USD
CY2019Q4	ofc	Credit Losses Financial Assetsand Other Instruments Allowancefor Credit Loss CreditLossesFinancialAssetsandOtherInstrumentsAllowanceforCreditLoss	97000	USD
	ofc	Off Balance Sheet Credit Loss Exposure Allowancefor Credit Loss Cumulative Effectof Changefor Adoptionof Credit Loss Guidance OffBalanceSheetCreditLossExposureAllowanceforCreditLossCumulativeEffectofChangeforAdoptionofCreditLossGuidance	1340000	USD
	ofc	Credit Losses Financial Assetsand Other Instruments Allowancefor Credit Loss Cumulative Effectof Changefor Adoptionof Credit Loss Guidance CreditLossesFinancialAssetsandOtherInstrumentsAllowanceforCreditLossCumulativeEffectofChangeforAdoptionofCreditLossGuidance	5541000	USD
	ofc	Off Balance Sheet Credit Loss Exposure Credit Loss Expense Reversal OffBalanceSheetCreditLossExposureCreditLossExpenseReversal	-1317000	USD
	ofc	Credit Losses Financial Assetsand Other Instruments Allowancefor Credit Loss Expense Reversal CreditLossesFinancialAssetsandOtherInstrumentsAllowanceforCreditLossExpenseReversal	-161000	USD
CY2020Q3	ofc	Off Balance Sheet Credit Loss Exposure Allowancefor Credit Loss OffBalanceSheetCreditLossExposureAllowanceforCreditLoss	23000	USD
CY2020Q3	ofc	Credit Losses Financial Assetsand Other Instruments Allowancefor Credit Loss CreditLossesFinancialAssetsandOtherInstrumentsAllowanceforCreditLoss	5477000	USD
	ofc	Lessor Operating Lease Average Termof Contract LessorOperatingLeaseAverageTermofContract	P5Y3M18D
CY2020Q3	us-gaap	Operating Lease Lease Income Lease Payments OperatingLeaseLeaseIncomeLeasePayments	106743000	USD
CY2019Q3	us-gaap	Operating Lease Lease Income Lease Payments OperatingLeaseLeaseIncomeLeasePayments	102389000	USD
	us-gaap	Operating Lease Lease Income Lease Payments OperatingLeaseLeaseIncomeLeasePayments	314845000	USD
	us-gaap	Operating Lease Lease Income Lease Payments OperatingLeaseLeaseIncomeLeasePayments	311226000	USD
CY2020Q3	us-gaap	Operating Lease Variable Lease Income OperatingLeaseVariableLeaseIncome	27132000	USD
CY2019Q3	us-gaap	Operating Lease Variable Lease Income OperatingLeaseVariableLeaseIncome	27072000	USD
	us-gaap	Operating Lease Variable Lease Income OperatingLeaseVariableLeaseIncome	82189000	USD
	us-gaap	Operating Lease Variable Lease Income OperatingLeaseVariableLeaseIncome	80553000	USD
CY2020Q3	us-gaap	Operating Lease Lease Income OperatingLeaseLeaseIncome	133875000	USD
CY2019Q3	us-gaap	Operating Lease Lease Income OperatingLeaseLeaseIncome	129461000	USD
	us-gaap	Operating Lease Lease Income OperatingLeaseLeaseIncome	397034000	USD
	us-gaap	Operating Lease Lease Income OperatingLeaseLeaseIncome	391779000	USD
CY2020Q3	us-gaap	Lessor Operating Lease Payments To Be Received Remainder Of Fiscal Year LessorOperatingLeasePaymentsToBeReceivedRemainderOfFiscalYear	107972000	USD
CY2019Q4	us-gaap	Lessor Operating Lease Payments To Be Received Next Twelve Months LessorOperatingLeasePaymentsToBeReceivedNextTwelveMonths	388310000	USD
CY2020Q3	us-gaap	Lessor Operating Lease Payments To Be Received Next Twelve Months LessorOperatingLeasePaymentsToBeReceivedNextTwelveMonths	410966000	USD
CY2019Q4	us-gaap	Lessor Operating Lease Payments To Be Received Two Years LessorOperatingLeasePaymentsToBeReceivedTwoYears	336482000	USD
CY2020Q3	us-gaap	Lessor Operating Lease Payments To Be Received Two Years LessorOperatingLeasePaymentsToBeReceivedTwoYears	362892000	USD
CY2019Q4	us-gaap	Lessor Operating Lease Payments To Be Received Three Years LessorOperatingLeasePaymentsToBeReceivedThreeYears	299356000	USD
CY2020Q3	us-gaap	Lessor Operating Lease Payments To Be Received Three Years LessorOperatingLeasePaymentsToBeReceivedThreeYears	307346000	USD
CY2019Q4	us-gaap	Lessor Operating Lease Payments To Be Received Four Years LessorOperatingLeasePaymentsToBeReceivedFourYears	245661000	USD
CY2020Q3	us-gaap	Lessor Operating Lease Payments To Be Received Four Years LessorOperatingLeasePaymentsToBeReceivedFourYears	258059000	USD
CY2019Q4	us-gaap	Lessor Operating Lease Payments To Be Received Five Years LessorOperatingLeasePaymentsToBeReceivedFiveYears	195246000	USD
CY2020Q3	ofc	Lessor Operating Lease Paymenttobe Receivedafter Year Four LessorOperatingLeasePaymenttobeReceivedafterYearFour	773582000	USD
CY2019Q4	us-gaap	Lessor Operating Lease Payments To Be Received Thereafter LessorOperatingLeasePaymentsToBeReceivedThereafter	474741000	USD
CY2020Q3	us-gaap	Lessor Operating Lease Payments To Be Received LessorOperatingLeasePaymentsToBeReceived	2220817000	USD
CY2019Q4	us-gaap	Lessor Operating Lease Payments To Be Received LessorOperatingLeasePaymentsToBeReceived	1939796000	USD
CY2020Q3	ofc	Lessee Rightof Use Asset LesseeRightofUseAsset	76900000	USD
CY2020Q3	us-gaap	Operating Lease Right Of Use Asset OperatingLeaseRightOfUseAsset	36442000	USD
CY2019Q4	us-gaap	Operating Lease Right Of Use Asset OperatingLeaseRightOfUseAsset	27864000	USD
CY2020Q3	us-gaap	Finance Lease Right Of Use Asset FinanceLeaseRightOfUseAsset	40432000	USD
CY2019Q4	us-gaap	Finance Lease Right Of Use Asset FinanceLeaseRightOfUseAsset	40458000	USD
CY2020Q3	ofc	Lease Rightof Use Assets LeaseRightofUseAssets	76874000	USD
CY2019Q4	ofc	Lease Rightof Use Assets LeaseRightofUseAssets	68322000	USD
CY2020Q3	us-gaap	Operating Lease Liability OperatingLeaseLiability	26382000	USD
CY2019Q4	us-gaap	Operating Lease Liability OperatingLeaseLiability	17317000	USD
CY2020Q3	us-gaap	Finance Lease Liability FinanceLeaseLiability	28000	USD
CY2019Q4	us-gaap	Finance Lease Liability FinanceLeaseLiability	702000	USD
CY2020Q3	ofc	Lease Liabilities LeaseLiabilities	26410000	USD
CY2019Q4	ofc	Lease Liabilities LeaseLiabilities	18019000	USD
CY2020Q3	us-gaap	Operating Lease Weighted Average Remaining Lease Term1 OperatingLeaseWeightedAverageRemainingLeaseTerm1	P54Y
CY2020Q3	us-gaap	Finance Lease Weighted Average Remaining Lease Term1 FinanceLeaseWeightedAverageRemainingLeaseTerm1	P1Y
CY2020Q3	us-gaap	Operating Lease Weighted Average Discount Rate Percent OperatingLeaseWeightedAverageDiscountRatePercent	0.0719
CY2020Q3	us-gaap	Finance Lease Weighted Average Discount Rate Percent FinanceLeaseWeightedAverageDiscountRatePercent	0.0362
CY2020Q3	us-gaap	Lease Cost LeaseCost	714000	USD
CY2019Q3	us-gaap	Lease Cost LeaseCost	422000	USD
	us-gaap	Lease Cost LeaseCost	1608000	USD
	us-gaap	Lease Cost LeaseCost	1260000	USD
	us-gaap	Operating Lease Payments OperatingLeasePayments	987000	USD
	us-gaap	Operating Lease Payments OperatingLeasePayments	804000	USD
	us-gaap	Finance Lease Principal Payments FinanceLeasePrincipalPayments	674000	USD
	us-gaap	Finance Lease Principal Payments FinanceLeasePrincipalPayments	14000	USD
CY2020Q3	us-gaap	Lessee Operating Lease Liability Payments Remainder Of Fiscal Year LesseeOperatingLeaseLiabilityPaymentsRemainderOfFiscalYear	615000	USD
CY2020Q3	us-gaap	Finance Lease Liability Payments Remainder Of Fiscal Year FinanceLeaseLiabilityPaymentsRemainderOfFiscalYear	0	USD
CY2020Q3	ofc	Lessee Lease Liability Payments Remainderof Fiscal Year LesseeLeaseLiabilityPaymentsRemainderofFiscalYear	615000	USD
CY2019Q4	us-gaap	Lessee Operating Lease Liability Payments Due Next Twelve Months LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths	1092000	USD
CY2019Q4	us-gaap	Finance Lease Liability Payments Due Next Twelve Months FinanceLeaseLiabilityPaymentsDueNextTwelveMonths	674000	USD
CY2019Q4	ofc	Lessee Lease Liability Payments Due Next Twelve Months LesseeLeaseLiabilityPaymentsDueNextTwelveMonths	1766000	USD
CY2020Q3	us-gaap	Lessee Operating Lease Liability Payments Due Next Twelve Months LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths	2513000	USD
CY2020Q3	us-gaap	Finance Lease Liability Payments Due Next Twelve Months FinanceLeaseLiabilityPaymentsDueNextTwelveMonths	14000	USD
CY2020Q3	ofc	Lessee Lease Liability Payments Due Next Twelve Months LesseeLeaseLiabilityPaymentsDueNextTwelveMonths	2527000	USD
CY2019Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Two LesseeOperatingLeaseLiabilityPaymentsDueYearTwo	1138000	USD
CY2019Q4	us-gaap	Finance Lease Liability Payments Due Year Two FinanceLeaseLiabilityPaymentsDueYearTwo	14000	USD
CY2019Q4	ofc	Lessee Lease Liability Payments Due Year Two LesseeLeaseLiabilityPaymentsDueYearTwo	1152000	USD
CY2020Q3	us-gaap	Lessee Operating Lease Liability Payments Due Year Two LesseeOperatingLeaseLiabilityPaymentsDueYearTwo	2566000	USD
CY2020Q3	us-gaap	Finance Lease Liability Payments Due Year Two FinanceLeaseLiabilityPaymentsDueYearTwo	14000	USD
CY2020Q3	ofc	Lessee Lease Liability Payments Due Year Two LesseeLeaseLiabilityPaymentsDueYearTwo	2580000	USD
CY2019Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Three LesseeOperatingLeaseLiabilityPaymentsDueYearThree	1162000	USD
CY2019Q4	us-gaap	Finance Lease Liability Payments Due Year Three FinanceLeaseLiabilityPaymentsDueYearThree	14000	USD
CY2019Q4	ofc	Lessee Lease Liability Payments Due Year Three LesseeLeaseLiabilityPaymentsDueYearThree	1176000	USD
CY2020Q3	us-gaap	Lessee Operating Lease Liability Payments Due Year Three LesseeOperatingLeaseLiabilityPaymentsDueYearThree	2601000	USD
CY2020Q3	us-gaap	Finance Lease Liability Payments Due Year Three FinanceLeaseLiabilityPaymentsDueYearThree	0	USD
CY2020Q3	ofc	Lessee Lease Liability Payments Due Year Three LesseeLeaseLiabilityPaymentsDueYearThree	2601000	USD
CY2019Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Four LesseeOperatingLeaseLiabilityPaymentsDueYearFour	1167000	USD
CY2019Q4	us-gaap	Finance Lease Liability Payments Due Year Four FinanceLeaseLiabilityPaymentsDueYearFour	0	USD
CY2019Q4	ofc	Lessee Lease Liability Payments Due Year Four LesseeLeaseLiabilityPaymentsDueYearFour	1167000	USD
CY2020Q3	us-gaap	Lessee Operating Lease Liability Payments Due Year Four LesseeOperatingLeaseLiabilityPaymentsDueYearFour	2636000	USD
CY2020Q3	us-gaap	Finance Lease Liability Payments Due Year Four FinanceLeaseLiabilityPaymentsDueYearFour	0	USD
CY2020Q3	ofc	Lessee Lease Liability Payments Due Year Four LesseeLeaseLiabilityPaymentsDueYearFour	2636000	USD
CY2019Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Five LesseeOperatingLeaseLiabilityPaymentsDueYearFive	1173000	USD
CY2019Q4	us-gaap	Finance Lease Liability Payments Due Year Five FinanceLeaseLiabilityPaymentsDueYearFive	0	USD
CY2019Q4	ofc	Lessee Lease Liability Payments Due Year Five LesseeLeaseLiabilityPaymentsDueYearFive	1173000	USD
CY2020Q3	ofc	Lessee Operating Lease Liabilitytobe Paidafter Year Four LesseeOperatingLeaseLiabilitytobePaidafterYearFour	118295000	USD
CY2020Q3	ofc	Finance Lease Liability Payments Due After Year Four FinanceLeaseLiabilityPaymentsDueAfterYearFour	0	USD
CY2020Q3	ofc	Lessee Lease Liability Payments Dueafter Year Four LesseeLeaseLiabilityPaymentsDueafterYearFour	118295000	USD
CY2019Q4	us-gaap	Lessee Operating Lease Liability Payments Due After Year Five LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive	100609000	USD
CY2019Q4	us-gaap	Finance Lease Liability Payments Due After Year Five FinanceLeaseLiabilityPaymentsDueAfterYearFive	0	USD
CY2019Q4	ofc	Lessee Lease Liability Payments Dueafter Year Five LesseeLeaseLiabilityPaymentsDueafterYearFive	100609000	USD
CY2020Q3	us-gaap	Lessee Operating Lease Liability Payments Due LesseeOperatingLeaseLiabilityPaymentsDue	129226000	USD
CY2020Q3	us-gaap	Finance Lease Liability Payments Due FinanceLeaseLiabilityPaymentsDue	28000	USD
CY2020Q3	ofc	Lessee Lease Liability Payments Due LesseeLeaseLiabilityPaymentsDue	129254000	USD
CY2019Q4	us-gaap	Lessee Operating Lease Liability Payments Due LesseeOperatingLeaseLiabilityPaymentsDue	106341000	USD
CY2019Q4	us-gaap	Finance Lease Liability Payments Due FinanceLeaseLiabilityPaymentsDue	702000	USD
CY2019Q4	ofc	Lessee Lease Liability Payments Due LesseeLeaseLiabilityPaymentsDue	107043000	USD
CY2020Q3	us-gaap	Lessee Operating Lease Liability Undiscounted Excess Amount LesseeOperatingLeaseLiabilityUndiscountedExcessAmount	102844000	USD
CY2020Q3	us-gaap	Finance Lease Liability Undiscounted Excess Amount FinanceLeaseLiabilityUndiscountedExcessAmount	0	USD
CY2020Q3	ofc	Lessee Lease Liability Imputed Interest LesseeLeaseLiabilityImputedInterest	102844000	USD
CY2019Q4	us-gaap	Lessee Operating Lease Liability Undiscounted Excess Amount LesseeOperatingLeaseLiabilityUndiscountedExcessAmount	89024000	USD
CY2019Q4	us-gaap	Finance Lease Liability Undiscounted Excess Amount FinanceLeaseLiabilityUndiscountedExcessAmount	0	USD
CY2019Q4	ofc	Lessee Lease Liability Imputed Interest LesseeLeaseLiabilityImputedInterest	89024000	USD
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CY2020Q3	us-gaap	Finance Lease Liability FinanceLeaseLiability	28000	USD
CY2020Q3	ofc	Lease Liabilities LeaseLiabilities	26410000	USD
CY2019Q4	us-gaap	Operating Lease Liability OperatingLeaseLiability	17317000	USD
CY2019Q4	us-gaap	Finance Lease Liability FinanceLeaseLiability	702000	USD
CY2019Q4	ofc	Lease Liabilities LeaseLiabilities	18019000	USD
CY2019Q3	us-gaap	Interest Costs Capitalized InterestCostsCapitalized	2900000	USD
CY2020Q3	us-gaap	Deferred Compensation Plan Assets DeferredCompensationPlanAssets	2672000	USD
CY2019Q4	us-gaap	Deferred Compensation Plan Assets DeferredCompensationPlanAssets	3060000	USD
CY2020Q3	us-gaap	Prepaid Expense And Other Assets PrepaidExpenseAndOtherAssets	110292000	USD
CY2019Q4	us-gaap	Prepaid Expense And Other Assets PrepaidExpenseAndOtherAssets	96076000	USD
CY2020Q3	us-gaap	Long Term Debt LongTermDebt	2181551000	USD
CY2019Q4	us-gaap	Long Term Debt LongTermDebt	1831139000	USD
CY2020Q3	us-gaap	Interest Costs Capitalized InterestCostsCapitalized	2900000	USD
	us-gaap	Interest Costs Capitalized InterestCostsCapitalized	9400000	USD
	us-gaap	Interest Costs Capitalized InterestCostsCapitalized	7300000	USD
CY2020Q3	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Before Reclassification After Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAfterTax	1428000	USD
CY2019Q3	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Before Reclassification After Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAfterTax	-11047000	USD
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	ofc	Numberof Joint Ventures With Redeemable Noncontrolling Interests NumberofJointVenturesWithRedeemableNoncontrollingInterests	2	joint_venture
CY2019Q4	us-gaap	Redeemable Noncontrolling Interest Equity Fair Value RedeemableNoncontrollingInterestEquityFairValue	29431000	USD
CY2018Q4	us-gaap	Redeemable Noncontrolling Interest Equity Fair Value RedeemableNoncontrollingInterestEquityFairValue	26260000	USD
	us-gaap	Minority Interest Decrease From Distributions To Noncontrolling Interest Holders MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders	13335000	USD
	us-gaap	Minority Interest Decrease From Distributions To Noncontrolling Interest Holders MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders	1656000	USD
CY2020Q3	us-gaap	Redeemable Noncontrolling Interest Equity Fair Value RedeemableNoncontrollingInterestEquityFairValue	23522000	USD
	us-gaap	Net Income Loss Attributable To Redeemable Noncontrolling Interest NetIncomeLossAttributableToRedeemableNoncontrollingInterest	2715000	USD
	us-gaap	Net Income Loss Attributable To Redeemable Noncontrolling Interest NetIncomeLossAttributableToRedeemableNoncontrollingInterest	2729000	USD
	us-gaap	Minority Interest Change In Redemption Value MinorityInterestChangeInRedemptionValue	4711000	USD
CY2019Q3	us-gaap	Redeemable Noncontrolling Interest Equity Fair Value RedeemableNoncontrollingInterestEquityFairValue	28677000	USD
CY2020Q3	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.275
CY2019Q3	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.275
	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.825
	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.825
	us-gaap	Revenues Revenues	445337000	USD
	us-gaap	Revenues Revenues	483441000	USD
CY2020Q3	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	20323000	USD
CY2019Q3	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	28697000	USD
	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	46240000	USD
	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	87946000	USD
CY2020Q3	us-gaap	Revenues Revenues	154766000	USD
CY2019Q3	us-gaap	Revenues Revenues	159431000	USD
CY2019Q3	us-gaap	Income Loss From Equity Method Investments IncomeLossFromEquityMethodInvestments	396000	USD
	us-gaap	Income Loss From Equity Method Investments IncomeLossFromEquityMethodInvestments	1372000	USD
CY2020Q3	ofc	Unconsolidated Joint Venture Net Operating Income Allocableto Parent UnconsolidatedJointVentureNetOperatingIncomeAllocabletoParent	1752000	USD
CY2019Q3	ofc	Unconsolidated Joint Venture Net Operating Income Allocableto Parent UnconsolidatedJointVentureNetOperatingIncomeAllocabletoParent	1601000	USD
	ofc	Unconsolidated Joint Venture Net Operating Income Allocableto Parent UnconsolidatedJointVentureNetOperatingIncomeAllocabletoParent	5190000	USD
	ofc	Unconsolidated Joint Venture Net Operating Income Allocableto Parent UnconsolidatedJointVentureNetOperatingIncomeAllocabletoParent	4071000	USD
CY2020Q3	ofc	Income Lossfrom Equity Method Investments Allocableto Depreciation Amortizationand Interest Expense IncomeLossfromEquityMethodInvestmentsAllocabletoDepreciationAmortizationandInterestExpense	1274000	USD
CY2019Q3	ofc	Income Lossfrom Equity Method Investments Allocableto Depreciation Amortizationand Interest Expense IncomeLossfromEquityMethodInvestmentsAllocabletoDepreciationAmortizationandInterestExpense	1202000	USD
	ofc	Income Lossfrom Equity Method Investments Allocableto Depreciation Amortizationand Interest Expense IncomeLossfromEquityMethodInvestmentsAllocabletoDepreciationAmortizationandInterestExpense	3814000	USD
	ofc	Income Lossfrom Equity Method Investments Allocableto Depreciation Amortizationand Interest Expense IncomeLossfromEquityMethodInvestmentsAllocabletoDepreciationAmortizationandInterestExpense	2859000	USD
CY2020Q3	ofc	Income Lossin Non Real Estate Equity Method Investments IncomeLossinNonRealEstateEquityMethodInvestments	-1000	USD
CY2019Q3	ofc	Income Lossin Non Real Estate Equity Method Investments IncomeLossinNonRealEstateEquityMethodInvestments	-3000	USD
	ofc	Income Lossin Non Real Estate Equity Method Investments IncomeLossinNonRealEstateEquityMethodInvestments	-4000	USD
	ofc	Income Lossin Non Real Estate Equity Method Investments IncomeLossinNonRealEstateEquityMethodInvestments	-5000	USD
CY2020Q3	us-gaap	Income Loss From Equity Method Investments IncomeLossFromEquityMethodInvestments	477000	USD
	us-gaap	Income Loss From Equity Method Investments IncomeLossFromEquityMethodInvestments	1207000	USD
CY2020Q3	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	20323000	USD
CY2019Q3	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	28697000	USD
	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	46240000	USD
	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	87946000	USD
CY2020Q3	ofc	Construction Contract And Other Service Expenses ConstructionContractAndOtherServiceExpenses	19220000	USD
CY2019Q3	ofc	Construction Contract And Other Service Expenses ConstructionContractAndOtherServiceExpenses	27802000	USD
	ofc	Construction Contract And Other Service Expenses ConstructionContractAndOtherServiceExpenses	44052000	USD
	ofc	Construction Contract And Other Service Expenses ConstructionContractAndOtherServiceExpenses	85130000	USD
CY2020Q3	us-gaap	Other Nonoperating Income OtherNonoperatingIncome	1746000	USD
CY2019Q3	us-gaap	Other Nonoperating Income OtherNonoperatingIncome	1842000	USD
	us-gaap	Other Nonoperating Income OtherNonoperatingIncome	5233000	USD
	us-gaap	Other Nonoperating Income OtherNonoperatingIncome	5977000	USD
CY2020Q3	ofc	Credit Losses Financial Assetsand Other Instruments Allowancefor Credit Loss Expense Reversal CreditLossesFinancialAssetsandOtherInstrumentsAllowanceforCreditLossExpenseReversal	-1465000	USD
CY2019Q3	ofc	Credit Losses Financial Assetsand Other Instruments Allowancefor Credit Loss Expense Reversal CreditLossesFinancialAssetsandOtherInstrumentsAllowanceforCreditLossExpenseReversal	0	USD
	ofc	Credit Losses Financial Assetsand Other Instruments Allowancefor Credit Loss Expense Reversal CreditLossesFinancialAssetsandOtherInstrumentsAllowanceforCreditLossExpenseReversal	-161000	USD
	ofc	Credit Losses Financial Assetsand Other Instruments Allowancefor Credit Loss Expense Reversal CreditLossesFinancialAssetsandOtherInstrumentsAllowanceforCreditLossExpenseReversal	0	USD
CY2020Q3	us-gaap	Gain Loss On Disposition Of Assets1 GainLossOnDispositionOfAssets1	0	USD
CY2019Q3	us-gaap	Gain Loss On Disposition Of Assets1 GainLossOnDispositionOfAssets1	0	USD
	us-gaap	Gain Loss On Disposition Of Assets1 GainLossOnDispositionOfAssets1	5000	USD
	us-gaap	Gain Loss On Disposition Of Assets1 GainLossOnDispositionOfAssets1	84469000	USD
CY2020Q3	us-gaap	Income Loss From Equity Method Investments IncomeLossFromEquityMethodInvestments	477000	USD
CY2019Q3	us-gaap	Income Loss From Equity Method Investments IncomeLossFromEquityMethodInvestments	396000	USD
	us-gaap	Income Loss From Equity Method Investments IncomeLossFromEquityMethodInvestments	1372000	USD
	us-gaap	Income Loss From Equity Method Investments IncomeLossFromEquityMethodInvestments	1207000	USD
CY2020Q3	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	16000	USD
CY2019Q3	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	-131000	USD
	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	95000	USD
	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	-113000	USD
CY2020Q3	ofc	Depreciation And Amortization For Real Estate Operations DepreciationAndAmortizationForRealEstateOperations	35332000	USD
CY2019Q3	ofc	Depreciation And Amortization For Real Estate Operations DepreciationAndAmortizationForRealEstateOperations	34692000	USD
	ofc	Depreciation And Amortization For Real Estate Operations DepreciationAndAmortizationForRealEstateOperations	101540000	USD
	ofc	Depreciation And Amortization For Real Estate Operations DepreciationAndAmortizationForRealEstateOperations	104290000	USD
CY2020Q3	us-gaap	Asset Impairment Charges AssetImpairmentCharges	1530000	USD
CY2019Q3	us-gaap	Asset Impairment Charges AssetImpairmentCharges	327000	USD
	us-gaap	Asset Impairment Charges AssetImpairmentCharges	1530000	USD
	us-gaap	Asset Impairment Charges AssetImpairmentCharges	327000	USD
CY2020Q3	us-gaap	Selling General And Administrative Expense SellingGeneralAndAdministrativeExpense	7467000	USD
CY2019Q3	us-gaap	Selling General And Administrative Expense SellingGeneralAndAdministrativeExpense	7929000	USD
	us-gaap	Selling General And Administrative Expense SellingGeneralAndAdministrativeExpense	23111000	USD
	us-gaap	Selling General And Administrative Expense SellingGeneralAndAdministrativeExpense	26066000	USD
CY2020Q3	ofc	Business Development Expenses And Land Carry Costs BusinessDevelopmentExpensesAndLandCarryCosts	1094000	USD
CY2019Q3	ofc	Business Development Expenses And Land Carry Costs BusinessDevelopmentExpensesAndLandCarryCosts	964000	USD
	ofc	Business Development Expenses And Land Carry Costs BusinessDevelopmentExpensesAndLandCarryCosts	3474000	USD
	ofc	Business Development Expenses And Land Carry Costs BusinessDevelopmentExpensesAndLandCarryCosts	2947000	USD
CY2020Q3	us-gaap	Interest Expense InterestExpense	17152000	USD
CY2019Q3	us-gaap	Interest Expense InterestExpense	17126000	USD
	us-gaap	Interest Expense InterestExpense	50789000	USD
	us-gaap	Interest Expense InterestExpense	54275000	USD
CY2020Q3	ofc	Unconsolidated Joint Venture Net Operating Income Allocableto Parent UnconsolidatedJointVentureNetOperatingIncomeAllocabletoParent	1752000	USD
CY2019Q3	ofc	Unconsolidated Joint Venture Net Operating Income Allocableto Parent UnconsolidatedJointVentureNetOperatingIncomeAllocabletoParent	1601000	USD
	ofc	Unconsolidated Joint Venture Net Operating Income Allocableto Parent UnconsolidatedJointVentureNetOperatingIncomeAllocabletoParent	5190000	USD
	ofc	Unconsolidated Joint Venture Net Operating Income Allocableto Parent UnconsolidatedJointVentureNetOperatingIncomeAllocabletoParent	4071000	USD
CY2020Q3	us-gaap	Gains Losses On Extinguishment Of Debt GainsLossesOnExtinguishmentOfDebt	-3237000	USD
CY2019Q3	us-gaap	Gains Losses On Extinguishment Of Debt GainsLossesOnExtinguishmentOfDebt	0	USD
	us-gaap	Gains Losses On Extinguishment Of Debt GainsLossesOnExtinguishmentOfDebt	-3237000	USD
	us-gaap	Gains Losses On Extinguishment Of Debt GainsLossesOnExtinguishmentOfDebt	0	USD
CY2020Q3	us-gaap	Gain Loss On Derivative Instruments Net Pretax GainLossOnDerivativeInstrumentsNetPretax	-53196000	USD
CY2019Q3	us-gaap	Gain Loss On Derivative Instruments Net Pretax GainLossOnDerivativeInstrumentsNetPretax	0	USD
	us-gaap	Gain Loss On Derivative Instruments Net Pretax GainLossOnDerivativeInstrumentsNetPretax	-53196000	USD
	us-gaap	Gain Loss On Derivative Instruments Net Pretax GainLossOnDerivativeInstrumentsNetPretax	0	USD
CY2020Q3	us-gaap	Profit Loss ProfitLoss	-31342000	USD
CY2019Q3	us-gaap	Profit Loss ProfitLoss	23246000	USD
	us-gaap	Profit Loss ProfitLoss	19329000	USD
	us-gaap	Profit Loss ProfitLoss	155127000	USD
CY2020Q3	us-gaap	Assets Assets	4120189000	USD
CY2019Q3	us-gaap	Assets Assets	3855369000	USD
CY2020Q3	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	20323000	USD
CY2019Q3	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	28697000	USD
	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	46240000	USD
	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	87946000	USD
CY2020Q3	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	20323000	USD
CY2019Q3	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	28697000	USD
	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	46240000	USD
	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	87946000	USD
CY2020Q3	us-gaap	Revenue Remaining Performance Obligation RevenueRemainingPerformanceObligation	82100000	USD
CY2020Q3	ofc	Revenue Remaining Performance Obligation Amounttobe Recognized Duringthe Remainderofthe Year RevenueRemainingPerformanceObligationAmounttobeRecognizedDuringtheRemainderoftheYear	21000000	USD
CY2020Q3	us-gaap	Net Income Loss NetIncomeLoss	-31845000	USD
CY2019Q3	us-gaap	Net Income Loss NetIncomeLoss	21257000	USD
	us-gaap	Net Income Loss NetIncomeLoss	15706000	USD
	us-gaap	Net Income Loss NetIncomeLoss	148907000	USD
CY2020Q3	us-gaap	Participating Securities Distributed And Undistributed Earnings Loss Basic ParticipatingSecuritiesDistributedAndUndistributedEarningsLossBasic	145000	USD
CY2019Q3	us-gaap	Participating Securities Distributed And Undistributed Earnings Loss Basic ParticipatingSecuritiesDistributedAndUndistributedEarningsLossBasic	123000	USD
	us-gaap	Participating Securities Distributed And Undistributed Earnings Loss Basic ParticipatingSecuritiesDistributedAndUndistributedEarningsLossBasic	365000	USD
	us-gaap	Participating Securities Distributed And Undistributed Earnings Loss Basic ParticipatingSecuritiesDistributedAndUndistributedEarningsLossBasic	495000	USD
CY2020Q3	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	-31990000	USD
CY2019Q3	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	21134000	USD
	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	15341000	USD
	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	148412000	USD
CY2020Q3	ofc	Dilutive Securities Effecton Basic Earnings Per Share Dilutive Redeemable Noncontrolling Interests DilutiveSecuritiesEffectonBasicEarningsPerShareDilutiveRedeemableNoncontrollingInterests	0	USD
CY2019Q3	ofc	Dilutive Securities Effecton Basic Earnings Per Share Dilutive Redeemable Noncontrolling Interests DilutiveSecuritiesEffectonBasicEarningsPerShareDilutiveRedeemableNoncontrollingInterests	0	USD
	ofc	Dilutive Securities Effecton Basic Earnings Per Share Dilutive Redeemable Noncontrolling Interests DilutiveSecuritiesEffectonBasicEarningsPerShareDilutiveRedeemableNoncontrollingInterests	0	USD
	ofc	Dilutive Securities Effecton Basic Earnings Per Share Dilutive Redeemable Noncontrolling Interests DilutiveSecuritiesEffectonBasicEarningsPerShareDilutiveRedeemableNoncontrollingInterests	100000	USD
CY2020Q3	us-gaap	Amount Of Dilutive Securities Stock Options And Restrictive Stock Units AmountOfDilutiveSecuritiesStockOptionsAndRestrictiveStockUnits	0	USD
CY2019Q3	us-gaap	Amount Of Dilutive Securities Stock Options And Restrictive Stock Units AmountOfDilutiveSecuritiesStockOptionsAndRestrictiveStockUnits	5000	USD
	us-gaap	Amount Of Dilutive Securities Stock Options And Restrictive Stock Units AmountOfDilutiveSecuritiesStockOptionsAndRestrictiveStockUnits	6000	USD
	us-gaap	Amount Of Dilutive Securities Stock Options And Restrictive Stock Units AmountOfDilutiveSecuritiesStockOptionsAndRestrictiveStockUnits	26000	USD
CY2020Q3	us-gaap	Net Income Loss Available To Common Stockholders Diluted NetIncomeLossAvailableToCommonStockholdersDiluted	-31990000	USD
CY2019Q3	us-gaap	Net Income Loss Available To Common Stockholders Diluted NetIncomeLossAvailableToCommonStockholdersDiluted	21139000	USD
	us-gaap	Net Income Loss Available To Common Stockholders Diluted NetIncomeLossAvailableToCommonStockholdersDiluted	15347000	USD
	us-gaap	Net Income Loss Available To Common Stockholders Diluted NetIncomeLossAvailableToCommonStockholdersDiluted	148538000	USD
CY2020Q3	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	111811000	shares
CY2019Q3	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	111582000	shares
	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	111778000	shares
	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	111036000	shares
CY2020Q3	ofc	Incremental Common Shares Attributableto Dilutive Effectof Redeemable Noncontrolling Interests IncrementalCommonSharesAttributabletoDilutiveEffectofRedeemableNoncontrollingInterests	0	shares
CY2019Q3	ofc	Incremental Common Shares Attributableto Dilutive Effectof Redeemable Noncontrolling Interests IncrementalCommonSharesAttributabletoDilutiveEffectofRedeemableNoncontrollingInterests	0	shares
	ofc	Incremental Common Shares Attributableto Dilutive Effectof Redeemable Noncontrolling Interests IncrementalCommonSharesAttributabletoDilutiveEffectofRedeemableNoncontrollingInterests	0	shares
	ofc	Incremental Common Shares Attributableto Dilutive Effectof Redeemable Noncontrolling Interests IncrementalCommonSharesAttributabletoDilutiveEffectofRedeemableNoncontrollingInterests	123000	shares
CY2020Q3	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	0	shares
CY2019Q3	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	361000	shares
	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	278000	shares
	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	313000	shares
CY2020Q3	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	111811000	shares
CY2019Q3	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	111943000	shares
	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	112056000	shares
	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	111472000	shares
CY2020Q3	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	-0.29
CY2019Q3	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.19
	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.14
	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.34
CY2020Q3	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	-0.29
CY2019Q3	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.19
	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.14
	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.33
CY2020Q3	us-gaap	Loss Contingency Estimate Of Possible Loss LossContingencyEstimateOfPossibleLoss	3100000	USD
CY2020Q3	ofc	Property Subjectto Environmental Indemnity Numberof Properties PropertySubjecttoEnvironmentalIndemnityNumberofProperties	3	property
CY2020Q3	ofc	Maximum Additional Costs Agreed To Be Paid By The Entity Under Environmental Indemnification Agreement MaximumAdditionalCostsAgreedToBePaidByTheEntityUnderEnvironmentalIndemnificationAgreement	19000000	USD

Files In Submission

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$CDP
COPT Defense Properties Stock $cdp

2020 Q4 Form 10-Q Financial Statement

#000086054620000039 Filed on October 30, 2020

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$CDP COPT Defense Properties Stock $cdp

2020 Q4 Form 10-Q Financial Statement

#000086054620000039 Filed on October 30, 2020

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$CDP
COPT Defense Properties Stock $cdp