Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
BASIC
Income (loss) from continuing operations attributable to common shareholders	$ (7,629)	$ 20,151	$ 70,189	$ 35,330
Income from discontinued operations attributable to common shareholders	0	18,569	1,682	15,294
Net income (loss) attributable to common shareholders	$ (7,629)	$ 38,720	$ 71,871	$ 50,624
Weighted-average number of common shares outstanding	234,018,062	229,463,522	233,457,400	228,337,871
Income (loss) from continuing operations (in USD per share)	$ (0.03)	$ 0.09	$ 0.30	$ 0.15
Income (loss) from discontinued operations (in USD per share)	0.00	0.08	0.01	0.07
Net income (loss) attributable to common shareholders (USD per share)	$ (0.03)	$ 0.17	$ 0.31	$ 0.22
DILUTED
Income (loss) from continuing operations attributable to common shareholders	$ (7,629)	$ 20,151	$ 70,189	$ 35,330
Impact of assumed conversions	0	0	0	0
Income (loss) from continuing operations attributable to common shareholders	(7,629)	20,151	70,189	35,330
Income from discontinued operations attributable to common shareholders	0	18,569	1,682	15,294
Impact of assumed conversions	0	0	0	0
Income from discontinued operations attributable to common shareholders	0	18,569	1,682	15,294
Net income (loss) attributable to common shareholders	$ (7,629)	$ 38,720	$ 71,871	$ 50,624
Effect of dilutive securities:
Share options (in shares)	0	458,588	319,438	492,149
Weighted-average common shares outstanding (in shares)	234,018,062	229,922,110	233,776,838	228,830,020
Income (loss) per common share:
Income from continuing operations (USD per share)	$ (0.03)	$ 0.09	$ 0.30	$ 0.15
Income (loss) from discontinued operations (USD per share)	0.00	0.08	0.01	0.07
Net income (loss) attributable to common shareholders (USD per share)	$ (0.03)	$ 0.17	$ 0.31	$ 0.22