Earnings (Loss) Per Common Share - Schedule of Earnings (Loss) Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Earnings Per Share [Abstract]
Net income (loss)	$ 26,382	$ (77,991)	$ 45,619	$ (60,332)
Net (income) loss attributable to redeemable noncontrolling interests	3,552	(8,160)	6,532	(2,481)
Net loss attributable to noncontrolling interests	0	0	127	0
Net income (loss) attributable to common shareholders	22,830	(69,831)	39,214	(57,851)
Distributions to participating securities	(153)	0	(527)	0
Net income (loss) available to common shareholders — basic and diluted	$ 22,677	$ (69,831)	$ 38,687	$ (57,851)
Weighted average number of common shares outstanding — basic and diluted (1)	119,835	114,744	118,588	105,347
Earnings (loss) per common share:
Basic (in dollars per share)	$ 0.19	$ (0.61)	$ 0.33	$ (0.55)
Diluted (in dollars per share)	$ 0.19	$ (0.61)	$ 0.33	$ (0.55)