Agreements and Transactions with Related Parties - Related Party Income (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Amounts Included in the Condensed Consolidated Statements of Operations
Asset management fees	$ 2,878	$ 2,859	$ 5,880	$ 5,727
Available Cash Distributions	2,029	2,105	3,945	3,953
Personnel and overhead reimbursements	606	783	1,331	1,581
Interest expense on deferred acquisition fees and external joint venture loans	133	128	256	255
Disposition fees	0	0	0	1,117
Operating expenses	5,646	5,875	11,412	12,633
Acquisition Fees Capitalized
Current acquisition fees	0	0	110	695
Deferred acquisition fees	0	0	88	555
Capitalized personnel and overhead reimbursements	0	0	70	89
Transaction fees incurred	$ 0	$ 0	$ 268	$ 1,339