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

Investing Receivables - Investing Receivables (Details) - Investing Receivables - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost basis	$ 77,362	$ 71,605
Allowance for credit losses	(1,415)	(2,851)
Investing receivables, net	75,947	68,754
Notes receivable from the City of Huntsville
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost basis	71,322	65,564
Other investing loans receivable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost basis	$ 6,040	$ 6,041

Amount of allowance for credit loss on financing receivable. Excludes allowance for financing receivable covered under loss sharing agreement.

Amount, before allowance for credit loss, of financing receivable.