Earnings per Share - Computation of Earnings per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Numerator:
Net (loss) income	$ (167)	$ (19,938)	$ 1,108	$ (36,601)
Noncontrolling interest	7,316	3,109	10,391	10,795
Dividends on preferred shares	13,669	5,569	26,650	16,707
Net income (loss) attributable to common shareholders	$ (21,152)	$ (28,616)	$ (35,933)	$ (64,103)
Denominator:
Weighted-average shares (denominator) (in shares)	238,401,343	211,414,368	232,036,802	211,460,840
Net loss per share—basic and diluted (in USD per share)	$ (0.09)	$ (0.14)	$ (0.15)	$ (0.30)