Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
BASIC
Net income attributable to common shareholders									$ 220,838	$ 79,067	$ 89,109
Weighted-average common shares outstanding - basic (in shares)									236,666,375	237,758,408	233,633,058
Net income attributable to common shareholders - basic (usd per share)	$ 0.10	$ 0.91	$ (0.01)	$ (0.07)	$ 0.12	$ 0.02	$ 0.02	$ 0.17	$ 0.93	$ 0.33	$ 0.38
DILUTED:
Net income attributable to common shareholders - basic									$ 220,838	$ 79,067	$ 89,109
Impact of assumed conversions									2,528	147	(159)
Net income attributable to common shareholders									$ 223,366	$ 79,214	$ 88,950
Weighted-average common shares outstanding - basic (in shares)									236,666,375	237,758,408	233,633,058
Effect of dilutive securities:
Unvested share-based payment awards and options (in shares)									528,495	86,285	230,352
Operating Partnership Units (in units)									3,616,120	3,693,144	3,815,621
Weighted-average common shares outstanding (in shares)									240,810,990	241,537,837	237,679,031
Net income (loss) attributable to common shareholders - per common share diluted (usd per share)	$ 0.10	$ 0.90	$ (0.01)	$ (0.07)	$ 0.12	$ 0.02	$ 0.02	$ 0.17	$ 0.93	$ 0.33	$ 0.37