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		9 Months Ended
Debt, Net (Details)	Jun. 29, 2015 USD ($)	May. 06, 2015 USD ($) extensions	Apr. 20, 2015	Sep. 30, 2015 USD ($)	Sep. 30, 2014 USD ($)	Sep. 30, 2015 USD ($)	Sep. 30, 2014 USD ($)	Aug. 28, 2015 USD ($)	May. 05, 2015 USD ($)	Dec. 31, 2014 USD ($)
Debt
Carrying Value				$ 2,121,240,000		$ 2,121,240,000				$ 1,920,057,000
Interest costs capitalized				1,500,000	$ 1,300,000	5,600,000	$ 4,300,000
Line of Credit \| Revolving Credit Facility
Debt
Number of extensions \| extensions		2
Term of extension option		6 months
Line of Credit \| Revolving Credit Facility \| Minimum
Debt
Commitment fee (as a percent)		0.125%
Line of Credit \| Revolving Credit Facility \| Minimum \| London Interbank Offered Rate (LIBOR)
Debt
Variable rate, spread (as a percent)		0.875%
Line of Credit \| Revolving Credit Facility \| Maximum
Debt
Commitment fee (as a percent)		0.30%
Line of Credit \| Revolving Credit Facility \| Maximum \| London Interbank Offered Rate (LIBOR)
Debt
Variable rate, spread (as a percent)		1.60%
Line of Credit \| Term Loan Facilities
Debt
Maximum availability		$ 300,000,000							$ 250,000,000
Increase to maximum borrowing capacity		200,000,000
Aggregate maximum borrowing capacity		500,000,000
Proceeds from issuance of debt		$ 50,000,000
Line of Credit \| Term Loan Facilities \| Minimum \| London Interbank Offered Rate (LIBOR)
Debt
Variable rate, spread (as a percent)		0.90%
Line of Credit \| Term Loan Facilities \| Maximum \| London Interbank Offered Rate (LIBOR)
Debt
Variable rate, spread (as a percent)		1.85%
Mortgage and Other Secured Loans:
Debt
Carrying Value				324,466,000		324,466,000				424,016,000
Fixed rate mortgage loans
Debt
Carrying Value				288,217,000		$ 288,217,000				387,139,000
Stated interest rates, low end of range (as a percent)						3.96%
Stated interest rates, high end of range (as a percent)						7.87%
Unamortized premium included in carrying value				$ 24,000		$ 24,000				42,000
Debt settled through the surrender of real estate assets								$ 150,000,000
Weighted-average interest rate excluding incremental rate on default rate				6.07%		6.07%
Variable rate secured loans
Debt
Carrying Value				$ 36,249,000		$ 36,249,000				36,877,000
Description of variable rate basis						LIBOR
Stated interest rate (as a percent)				2.45%		2.45%
Variable rate secured loans \| London Interbank Offered Rate (LIBOR)
Debt
Variable rate, spread (as a percent)						2.25%
Variable rate secured loans \| Revolving Credit Facility
Debt
Weighted average interest rate (as a percent)				1.48%		1.48%
Revolving Credit Facility
Debt
Carrying Value				$ 87,000,000		$ 87,000,000				83,000,000
Description of variable rate basis						LIBOR
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%
Revolving Credit Facility \| Revolving Credit Facility
Debt
Maximum availability				800,000,000		$ 800,000,000
Term Loan Facilities
Debt
Carrying Value				$ 520,000,000		$ 520,000,000				520,000,000
Description of variable rate basis						LIBOR
Weighted average interest rate (as a percent)				1.78%		1.78%
Additional borrowing capacity available provided there is no default under the agreement				$ 380,000,000		$ 380,000,000
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)						2.60%
3.60% Senior Notes \| Unsecured senior notes
Debt
Carrying Value				$ 347,691,000		$ 347,691,000				347,496,000
Stated interest rate (as a percent)				3.60%		3.60%
Debt instrument, face amount				$ 350,000,000		$ 350,000,000
Unamortized discount included in carrying value				$ 2,300,000		$ 2,300,000				2,500,000
Interest rate on debt (as a percent)				3.70%		3.70%
5.250% Senior Notes \| Unsecured senior notes
Debt
Carrying Value				$ 246,074,000		$ 246,074,000				245,797,000
Stated interest rate (as a percent)				5.25%		5.25%
Debt instrument, face amount				$ 250,000,000		$ 250,000,000
Unamortized discount included in carrying value				$ 3,900,000		$ 3,900,000				4,200,000
Interest rate on debt (as a percent)				5.49%		5.49%
3.70% Senior Notes \| Unsecured senior notes
Debt
Carrying Value				$ 297,830,000		$ 297,830,000				297,569,000
Stated interest rate (as a percent)				3.70%		3.70%
Debt instrument, face amount				$ 300,000,000		$ 300,000,000
Unamortized discount included in carrying value				$ 2,200,000		$ 2,200,000				2,400,000
Interest rate on debt (as a percent)				3.85%		3.85%
5.000% Senior Notes \| Unsecured senior notes
Debt
Carrying Value				$ 296,646,000		$ 296,646,000				0
Stated interest rate (as a percent)	5.00%			5.00%		5.00%
Debt instrument, face amount	$ 300,000,000
Unamortized discount included in carrying value				$ 3,400,000		$ 3,400,000
Interest rate on debt (as a percent)				5.15%		5.15%
Debt issuance as a percentage of principal amount	99.51%
Proceeds from debt, net	$ 296,600,000
Redemption price ( as a percent)	100.00%
5.000% Senior Notes \| Unsecured senior notes \| Adjusted Treasury
Debt
Basis points used in determining redemption price prior to maturity	0.45%
Unsecured notes payable
Debt
Carrying Value				$ 1,533,000		$ 1,533,000				1,607,000
Stated interest rate (as a percent)				0.00%		0.00%
Unamortized discount included in carrying value				$ 578,000		$ 578,000				654,000
4.25% Exchangeable Senior Notes
Debt
Carrying Value				$ 0		$ 0				$ 572,000
Percentage of principal amount redeemed			100.00%