Equity - Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Numerator - Basic:
Net loss	$ (10,183)	$ (12,269)	$ (8,963)	$ (23,599)
Private perpetual preferred unit distributions	(1,050)	(1,050)	(3,151)	(3,147)
Net loss attributable to non-controlling interests	4,256	5,115	4,591	10,244
Earnings allocated to unvested shares	(9)	(24)	(18)	(60)
Net loss attributable to common stockholders – basic	(6,986)	(8,228)	(7,541)	(16,562)
Numerator - Diluted:
Net loss	(10,183)	(12,269)	(8,963)	(23,599)
Private perpetual preferred unit distributions	(1,050)	(1,050)	(3,151)	(3,147)
Earnings allocated to unvested shares	(9)	(24)	(18)	(60)
Net loss attributable to common stockholders – diluted	$ (11,242)	$ (13,343)	$ (12,132)	$ (26,806)
Denominator:
Weighted average shares outstanding - basic (in shares)	172,494,000	173,048,000	172,487,000	176,299,000
Operating partnership units (in shares)	105,222,000	107,892,000	105,342,000	109,341,000
Effect of dilutive securities:
Stock-based compensation plans (in shares)	0	0	0	0
Weighted average shares outstanding - diluted (in shares)	277,716,000	280,940,000	277,829,000	285,640,000
Earnings per share:
Basic (in USD per share)	$ (0.04)	$ (0.05)	$ (0.04)	$ (0.09)
Diluted (in USD per share)	$ (0.04)	$ (0.05)	$ (0.04)	$ (0.09)
Antidilutive securities (in shares)	1,084,264	0	997,811	169,848