Equity - Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Numerator - Basic:
Net income	$ 9,856	$ 18,058
Private perpetual preferred unit distributions	(234)	(234)
Net income attributable to non-controlling interests	(3,945)	(8,056)
Earnings allocated to unvested shares	(7)	(6)
Net income attributable to common stockholders - basic	5,670	9,762
Numerator - Diluted:
Net income	9,856	18,058
Private perpetual preferred unit distributions	(234)	(234)
Earnings allocated to unvested shares	(7)	(6)
Net income attributable to common stockholders - diluted	$ 9,615	$ 17,818
Denominator:
Weighted average shares outstanding - basic (in shares)	175,850,000	162,667,000
Operating partnership units (in shares)	122,199,000	134,157,000
Effect of dilutive securities:
Stock-based compensation plans (in shares)	0	3,000
Weighted average shares outstanding - diluted (in shares)	298,049,000	296,827,000
Earnings per share:
Basic (in USD per share)	$ 0.03	$ 0.06
Diluted (in USD per share)	$ 0.03	$ 0.06
Antidilutive securities (in shares)	684	419,347