Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
BASIC
Net income (loss) attributable to common shareholders	$ (15,957)	$ 40,397
Weighted-average number of common shares outstanding - basic	238,072,081	237,179,526
Income (loss) per common share:
Net income (loss) attributable to common shares outstanding - basic (in dollars per share)	$ (0.07)	$ 0.17
DILUTED
Impact of assumed conversions	$ 0	$ (19)
Net income (loss) attributable to common shareholders	$ (15,957)	$ 40,378
Effect of dilutive securities:
Share options (in shares)	0	136,881
OP Units (in shares)	0	3,771,642
Weighted-average common shares outstanding (in shares)	238,072,081	241,088,049
Income (loss) per common share:
Net income (loss) attributable to common shareholders - per common share diluted (in dollars per share)	$ (0.07)	$ 0.17