COPT Defense Properties Quarterly report [Sections 13 or 15(d)]

Quarterly report [Sections 13 or 15(d)]

Debt, Net - Schedule of Debt Maturities (Details)

Debt, Net - Schedule of Debt Maturities (Details)	3 Months Ended
Debt, Net - Schedule of Debt Maturities (Details)	Mar. 31, 2026 USD ($) extension $ / shares	Mar. 16, 2026	Dec. 31, 2025 USD ($)
Debt
Carrying Value	$ 2,546,958,000		$ 2,767,834,000
Net deferred financing costs	3,800,000		4,100,000
Mortgage and Other Secured Debt
Debt
Carrying Value	$ 183,866,000		142,189,000
Fixed-rate mortgage debt \| Mortgage and Other Secured Debt
Debt
Interest rate	3.82%
Carrying Value	$ 35,786,000		36,064,000
Variable-rate secured debt \| Mortgage and Other Secured Debt
Debt
Carrying Value	$ 10,080,000		10,125,000
Variable rate, additional spread over SOFR	0.10%
Weighted average interest rate	5.20%
Variable-rate secured debt \| Mortgage and Other Secured Debt \| Interest rate swaps
Debt
Weighted average interest rate	3.10%
Variable-rate secured debt \| Mortgage and Other Secured Debt \| Maximum
Debt
Variable rate, spread over SOFR	1.45%
Revolving Development Facility \| Mortgage and Other Secured Debt
Debt
Carrying Value	$ 138,000,000		96,000,000
Weighted average interest rate	5.00%
Extension option period	12 months
Extension fee percentage	0.25%
Revolving Development Facility \| Mortgage and Other Secured Debt \| Minimum
Debt
Variable rate, spread over SOFR	1.25%
Revolving Development Facility \| Mortgage and Other Secured Debt \| Maximum
Debt
Variable rate, spread over SOFR	1.90%
Credit Agreement \| Line of Credit \| Revolving Credit Facility
Debt
Carrying Value	$ 190,000,000		54,000,000
Weighted average interest rate	4.50%
Extension option period	6 months
Extension fee percentage	0.0625%
Number of extensions \| extension	2
Credit Agreement \| Line of Credit \| Revolving Credit Facility \| Minimum
Debt
Variable rate, spread over SOFR	0.725%
Credit Agreement \| Line of Credit \| Revolving Credit Facility \| Maximum
Debt
Variable rate, spread over SOFR	1.40%
Credit Agreement \| Term Loan Facility \| Term Loan Facility
Debt
Interest rate	4.70%
Carrying Value	$ 49,932,000		49,911,000
Extension option period	12 months
Extension fee percentage	0.125%
Credit Agreement \| Term Loan Facility \| Term Loan Facility \| Minimum
Debt
Variable rate, spread over SOFR	0.85%
Credit Agreement \| Term Loan Facility \| Term Loan Facility \| Maximum
Debt
Variable rate, spread over SOFR	1.70%
5.25%, $345,000 aggregate principal \| Unsecured Senior Notes
Debt
Interest rate	5.25%
Debt instrument, face amount	$ 345,000,000
Carrying Value	$ 339,956,000		339,470,000
Exchange rate of notes	0.0335584
Exchange price (in dollars per share) \| $ / shares	$ 29.80
Unamortized discounts and/or commissions included in carrying value	$ 4,500,000		4,900,000
Effective interest rate on debt	5.80%
2.00%, $400,000 aggregate principal \| Unsecured Senior Notes
Debt
Interest rate	2.00%
Debt instrument, face amount	$ 400,000,000
Carrying Value	398,584,000		398,459,000
Unamortized discounts and/or commissions included in carrying value	$ 1,000,000.0		1,100,000
Effective interest rate on debt	2.10%
4.50%, $400,000 aggregate principal \| Unsecured Senior Notes
Debt
Interest rate	4.50%
Debt instrument, face amount	$ 400,000,000
Carrying Value	394,601,000		394,326,000
Unamortized discounts and/or commissions included in carrying value	$ 4,100,000		4,300,000
Effective interest rate on debt	4.80%
2.75%, $600,000 aggregate principal \| Unsecured Senior Notes
Debt
Interest rate	2.75%
Debt instrument, face amount	$ 600,000,000
Carrying Value	593,767,000		593,476,000
Unamortized discounts and/or commissions included in carrying value	$ 5,400,000		5,700,000
Effective interest rate on debt	2.90%
2.90%, $400,000 aggregate principal \| Unsecured Senior Notes
Debt
Interest rate	2.90%
Debt instrument, face amount	$ 400,000,000
Carrying Value	396,241,000		396,130,000
Unamortized discounts and/or commissions included in carrying value	$ 3,100,000		3,200,000
Effective interest rate on debt	3.00%
2.25%, $400,000 aggregate principal \| Unsecured Senior Notes
Debt
Interest rate	2.25%	2.25%
Debt instrument, face amount	$ 400,000,000
Carrying Value	$ 0		399,812,000
Unamortized discounts and/or commissions included in carrying value			$ 153,000
Effective interest rate on debt			2.50%
Unsecured note payable \| Unsecured note payable
Debt
Interest rate	0.00%
Carrying Value	$ 11,000		$ 61,000
Unamortized discounts and/or commissions included in carrying value			$ 1,000