Fair Value Measurements - Fair Value of Financial Instruments (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Financial liabilities:
Mortgages payable, net	$ 92,075	$ 94,155
Unsecured notes payable, net	1,185,479	796,247
Unsecured term loans, net	467,391	716,523
Unsecured revolving line of credit	0	18,000
Carrying Value
Financial liabilities:
Mortgages payable, net	92,075	94,155
Unsecured notes payable, net	1,185,479	796,247
Unsecured term loans, net	467,391	716,523
Unsecured revolving line of credit	0	18,000
Derivative liability	34,804	12,288
Fair Value
Financial liabilities:
Mortgages payable, net	94,078	98,082
Unsecured notes payable, net	1,205,002	822,883
Unsecured term loans, net	458,788	720,000
Unsecured revolving line of credit	0	18,000
Derivative liability	$ 34,804	$ 12,288