Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
BASIC
Income from continuing operations attributable to common shareholders									$ 89,109	$ 103,418	$ 37,652
Income from discontinued operations attributable to common shareholders									0	1,682	48,672
Net income attributable to common shareholders									$ 89,109	$ 105,100	$ 86,324
Weighted-average common shares outstanding - basic (in shares)									233,633,058	233,455,056	228,966,253
Income from continuing operations, basic (usd per share)									$ 0.38	$ 0.44	$ 0.17
Income from discontinued operations, basic (usd per share)									0.00	0.01	0.21
Net income attributable to common shareholders, basic (usd per share)	$ 0.06	$ (0.12)	$ 0.23	$ 0.21	$ 0.14	$ (0.03)	$ 0.20	$ 0.14	$ 0.38	$ 0.45	$ 0.38
DILUTED:
Impact of assumed conversions									$ (159)	$ 0	$ 0
Income from continuing operations attributable to common shareholders									88,950	103,418	37,652
Income from discontinued operations									0	1,682	48,672
Impact of assumed conversions:									0	0	0
Income from discontinued operations attributable to common shareholders									0	1,682	48,672
Net income attributable to common shareholders									$ 88,950	$ 105,100	$ 86,324
Weighted-average common shares outstanding - basic (in shares)									233,633,058	233,455,056	228,966,253
Effect of dilutive securities:
Share options (in shares)									230,352	296,719	470,455
Operating Partnership Units (in units)									3,815,621	0	0
Weighted-average common shares outstanding (in shares)									237,679,031	233,751,775	229,436,708
Income from continuing operations, diluted (usd per share)									$ 0.37	$ 0.44	$ 0.17
Income from discontinued operations, diluted (usd per share)									0.00	0.01	0.21
Net income attributable to common shareholders, diluted (usd per share)	$ 0.06	$ (0.12)	$ 0.23	$ 0.20	$ 0.14	$ (0.03)	$ 0.20	$ 0.14	$ 0.37	$ 0.45	$ 0.38