Equity - Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended												12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Numerator - Basic:
Net income (loss)	$ 710	$ (12,269)	$ (19,618)	$ 8,288	$ 28,720	$ 26,784	$ 18,930	$ 9,856	$ 39,781	$ 29,230	$ 30,184	$ 18,058	$ (22,889)	$ 84,290	$ 117,253
Private perpetual preferred unit distributions													(4,197)	(1,743)	(936)
Net (income) loss attributable to non-controlling interest													10,374	(33,102)	(50,714)
Earnings allocated to unvested shares													(60)	(45)	(38)
Net income (loss) attributable to common stockholders - basic													(16,772)	49,400	65,565
Numerator - Diluted:
Net income (loss)	$ 710	$ (12,269)	$ (19,618)	$ 8,288	$ 28,720	$ 26,784	$ 18,930	$ 9,856	$ 39,781	$ 29,230	$ 30,184	$ 18,058	(22,889)	84,290	117,253
Private perpetual preferred unit distributions													(4,197)	(1,743)	(936)
Earnings allocated to unvested shares													(60)	(45)	(38)
Net income (loss) attributable to common stockholders - diluted													$ (27,146)	$ 82,502	$ 116,279
Denominator:
Weighted average shares outstanding - basic (in shares)													175,169,000	178,340,000	167,571,000
Operating partnership units (in shares)													108,657,000	119,458,000	129,687,000
Effect of dilutive securities:
Stock-based compensation plans (in shares)													11,000	0	1,000
Weighted average shares outstanding - dilutive (in shares)													283,837,000	297,798,000	297,259,000
Earnings per share:
Basic (in USD per share)													$ (0.10)	$ 0.28	$ 0.39
Diluted (in USD per share)													$ (0.10)	$ 0.28	$ 0.39
Antidilutive securities (in shares)													307,536	416,492	485,865