Investments in Unconsolidated Real Estate Ventures - Condensed Combined Financial Information (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Combined balance sheet information:
Real estate, net	$ 2,287,736		$ 2,287,736		$ 2,493,961
Other assets, net	274,321		274,321		291,092
Total assets	2,562,057		2,562,057		2,785,053
Borrowings, net	1,211,210		1,211,210		1,187,856
Other liabilities, net	143,939		143,939		168,243
Total liabilities	1,355,149		1,355,149		1,356,099
Total equity	1,206,908		1,206,908		1,428,954
Total liabilities and equity	2,562,057		2,562,057		$ 2,785,053
Combined income statement information:
Total revenue	47,235	$ 65,110	162,128	$ 199,897
Operating income	1,296	10,925	(24,418)	21,034
Net loss	$ (6,265)	$ (3,602)	(60,331)	$ (20,289)
Landmark | Woodglen
Combined income statement information:
Loss from sale			$ 16,400