Earnings (Losses) Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Jan. 31, 2017
Net income (loss) (numerator):
Income (loss) from continuing operations, net of tax	$ (119,285)	$ (97,839)	$ (382,389)	$ (681,048)
Less: net (income) loss attributable to noncontrolling interest	(2,113)	(1,185)	(5,001)	990
Less: (earnings) losses allocated to unvested shareholders	3,463	2,698	10,580	14,683
Adjusted income (loss) from continuing operations, net of tax - basic	(117,935)	(96,326)	(376,810)	(665,375)
Income (loss) from discontinued operations, net of tax	$ (27,134)	$ (12,187)	$ (43,077)	$ (14,097)
Weighted-average number of shares outstanding - basic	279,313	276,707	278,670	276,369
Earnings (losses) Per Share - Basic
Basic from continuing operations (in dollars per share)	$ (0.42)	$ (0.35)	$ (1.35)	$ (2.41)
Basic from discontinued operations (in dollars per share)	(0.10)	(0.04)	(0.16)	(0.05)
Total Basic (in dollars per share)	$ (0.52)	$ (0.39)	$ (1.51)	$ (2.46)
DILUTED EPS:
Adjusted income (loss) from continuing operations, net of tax - basic	$ (117,935)	$ (96,326)	$ (376,810)	$ (665,375)
Adjusted income (loss) from continuing operations, net of tax - diluted	(117,935)	(96,326)	(376,810)	(665,375)
Income (loss) from discontinued operations, net of tax	$ (27,134)	$ (12,187)	$ (43,077)	$ (14,097)
Weighted-average number of shares outstanding - basic	279,313	276,707	278,670	276,369
Weighted-average number of shares outstanding - diluted	279,313	276,707	278,670	276,369
Earnings (losses) per share:
Diluted from continuing operations (in dollars per share)	$ (0.42)	$ (0.35)	$ (1.35)	$ (2.41)
Diluted from discontinued operations (in dollars per share)	(0.10)	(0.04)	(0.16)	(0.05)
Total Diluted (in dollars per share)	$ (0.52)	$ (0.39)	$ (1.51)	$ (2.46)
0.75% senior exchangeable notes due January 2024
Earnings (losses) per share:
Aggregate amount of senior notes	$ 575,000		$ 575,000		$ 575,000
Interest rate on senior notes due (as a percent)	0.75%		0.75%
0.75% senior exchangeable notes due January 2024 | Minimum
Earnings (losses) per share:
Share issued price (in dollars per share)	$ 25.16		$ 25.16