CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY - USD ($) shares in Thousands, $ in Thousands	Common Shares	Additional Paid-in Capital	Accumulated Deficit	Accumulated Other Comprehensive Income	Treasury Stock	Total
Balance at Dec. 31, 2012	$ 3,914	$ 1,712,880	$ (683,176)	$ 3,685	$ (8,397)	$ 1,028,906
Balance (in shares) at Dec. 31, 2012	391,424
Increase (Decrease) in Shareholders' Equity
Equity-based compensation		69,101				69,101
Derivatives, net				(1,527)		(1,527)
Restricted stock awards and units	$ 6	(6)
Restricted stock awards and units (in shares)	550
Restricted stock forfeitures		6			(6)
Purchase of treasury stock		(446)			(12,655)	(13,101)
Net income (loss)			(91,044)			(91,044)
Balance at Dec. 31, 2013	$ 3,920	1,781,535	(774,220)	2,158	(21,058)	992,335
Balance (in shares) at Dec. 31, 2013	391,974
Increase (Decrease) in Shareholders' Equity
Equity-based compensation		79,741				79,741
Derivatives, net				(1,391)		(1,391)
Restricted stock awards and units	$ 4	(4)
Restricted stock awards and units (in shares)	469
Restricted stock forfeitures		2			(2)
Purchase of treasury stock		(1,084)			(10,012)	(11,096)
Net income (loss)			279,370			279,370
Balance at Dec. 31, 2014	$ 3,924	1,860,190	(494,850)	767	(31,072)	1,338,959
Balance (in shares) at Dec. 31, 2014	392,443
Increase (Decrease) in Shareholders' Equity
Equity-based compensation		75,267				75,267
Derivatives, net				$ (767)		(767)
Restricted stock awards and units	$ 15	(15)
Restricted stock awards and units (in shares)	1,460
Restricted stock forfeitures		16			(16)
Purchase of treasury stock		(2,269)			(15,841)	(18,110)
Net income (loss)			(69,836)			(69,836)
Balance at Dec. 31, 2015	$ 3,939	$ 1,933,189	$ (564,686)		$ (46,929)	$ 1,325,513
Balance (in shares) at Dec. 31, 2015	393,903