Debt Obligations - Mortgage Payable (Details) - Mortgages payable - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Jul. 31, 2021
Debt Instrument [Line Items]
Weighted average interest rate on mortgage debt (as a percentage)	4.14%		4.14%
Average maturity			4 years 4 months 2 days
Interest expense	$ 1,378	$ 1,468	$ 2,808	$ 2,943
Subsequent Event
Debt Instrument [Line Items]
Weighted average interest rate on mortgage debt (as a percentage)					4.46%
Outstanding principal balance					$ 17,000