COPT Defense Properties Quarterly report pursuant to Section 13 or 15(d)

Quarterly report pursuant to Section 13 or 15(d)

Debt, Net (Details)

Debt, Net (Details)	3 Months Ended		6 Months Ended
Debt, Net (Details)	Jun. 30, 2018 USD ($) extension	Jun. 30, 2017 USD ($)	Jun. 30, 2018 USD ($) extension	Jun. 30, 2017 USD ($)	Dec. 31, 2017 USD ($)
Debt
Carrying Value	$ 1,871,445,000		$ 1,871,445,000		$ 1,828,333,000
Interest costs capitalized	1,400,000	$ 1,600,000	2,800,000	$ 3,100,000
Secured Debt
Debt
Carrying Value	$ 161,893,000		$ 161,893,000		163,838,000
Line of Credit \| Revolving Credit Facility
Debt
Number of extensions \| extension	2		2
Extension option period (in years)			6 months
Line of credit facility, extension fee percentage			0.075%
Loans payable
Debt
Deferred financing costs, net	$ 4,500,000		$ 4,500,000		5,000,000
Fixed rate debt \| Secured Debt
Debt
Carrying Value	148,950,000		148,950,000		150,723,000
Unamortized premium included in carrying value	$ 315,000		$ 315,000		349,000
Weighted average interest rate (as a percent)	4.18%		4.18%
Fixed rate debt \| Secured Debt \| Minimum
Debt
Stated interest rate (as a percent)	3.82%		3.82%
Fixed rate debt \| Secured Debt \| Maximum
Debt
Stated interest rate (as a percent)	7.87%		7.87%
Variable-rate debt \| Secured Debt
Debt
Carrying Value	$ 12,943,000		$ 12,943,000		13,115,000
Stated interest rate (as a percent)	3.83%		3.83%
Variable-rate debt \| Secured Debt \| London Interbank Offered Rate (LIBOR)
Debt
Variable rate, spread (as a percent)			1.85%
Revolving Credit Facility
Debt
Carrying Value	$ 170,000,000		$ 170,000,000		126,000,000
Weighted average interest rate (as a percent)	3.19%		3.19%
Revolving Credit Facility \| Minimum \| London Interbank Offered Rate (LIBOR)
Debt
Variable rate, spread (as a percent)			0.875%
Revolving Credit Facility \| Maximum \| London Interbank Offered Rate (LIBOR)
Debt
Variable rate, spread (as a percent)			1.60%
Term Loan Facilities
Debt
Carrying Value	$ 348,185,000		$ 348,185,000		347,959,000
Weighted average interest rate (as a percent)	3.35%		3.35%
Aggregate additional borrowing capacity available	$ 350,000,000		$ 350,000,000
Term Loan Facilities \| Minimum \| London Interbank Offered Rate (LIBOR)
Debt
Variable rate, spread (as a percent)			0.90%
Term Loan Facilities \| Maximum \| London Interbank Offered Rate (LIBOR)
Debt
Variable rate, spread (as a percent)			1.85%
3.60% Senior Notes \| Unsecured senior notes
Debt
Carrying Value	347,767,000		$ 347,767,000		347,551,000
Debt instrument, face amount	$ 350,000,000		$ 350,000,000
Stated interest rate (as a percent)	3.60%		3.60%
Unamortized discount included in carrying value	$ 1,500,000		$ 1,500,000		1,700,000
Interest rate on debt (as a percent)	3.70%		3.70%
5.250% Senior Notes \| Unsecured senior notes
Debt
Carrying Value	$ 246,887,000		$ 246,887,000		246,645,000
Debt instrument, face amount	$ 250,000,000		$ 250,000,000
Stated interest rate (as a percent)	5.25%		5.25%
Unamortized discount included in carrying value	$ 2,800,000		$ 2,800,000		3,000,000
Interest rate on debt (as a percent)	5.49%		5.49%
3.70% Senior Notes \| Unsecured senior notes
Debt
Carrying Value	$ 298,567,000		$ 298,567,000		298,322,000
Debt instrument, face amount	$ 300,000,000		$ 300,000,000
Stated interest rate (as a percent)	3.70%		3.70%
Unamortized discount included in carrying value	$ 1,100,000		$ 1,100,000		1,300,000
Interest rate on debt (as a percent)	3.85%		3.85%
5.000% Senior Notes \| Unsecured senior notes
Debt
Carrying Value	$ 296,918,000		$ 296,918,000		296,731,000
Debt instrument, face amount	$ 300,000,000		$ 300,000,000
Stated interest rate (as a percent)	5.00%		5.00%
Unamortized discount included in carrying value	$ 2,600,000		$ 2,600,000		2,700,000
Interest rate on debt (as a percent)	5.15%		5.15%
Unsecured notes payable
Debt
Carrying Value	$ 1,228,000		$ 1,228,000		1,287,000
Stated interest rate (as a percent)	0.00%		0.00%
Unamortized discount included in carrying value	$ 333,000		$ 333,000		$ 373,000