CONSOLIDATED STATEMENTS OF EQUITY - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-In- Capital	Treasury Stock	Accumulated Deficit	Stockholders' Equity	Noncontrolling Interest
Balances at beginning of period at Dec. 31, 2014	$ 2,882,241	$ 1,870	$ 4,034,655	$ (46,800)	$ (1,108,001)	$ 2,881,724	$ 517
Balances at beginning of period (in shares) at Dec. 31, 2014		187,038,000
Compensation expense related to restricted stock grants	31,651		31,651			31,651
Net income (loss)	(458,155)				(457,477)	(457,477)	(678)
Issuance of common stock under Associate Stock Purchase Plan	2,870	$ 1	2,869			2,870
Issuance of common stock under Associate Stock Purchase Plan (in shares)		122,000
Restricted stock, net		$ 12	(12)
Restricted stock, net (in shares)		1,179,000
Other	120		120			120
Balances at end of period (in shares) at Dec. 31, 2015		188,339,000
Balances at end of period at Dec. 31, 2015	2,458,727	$ 1,883	4,069,283	(46,800)	(1,565,478)	2,458,888	(161)
Compensation expense related to restricted stock grants	32,285		32,285			32,285
Net income (loss)	(404,636)				(404,397)	(404,397)	(239)
Issuance of common stock under Associate Stock Purchase Plan	2,349	$ 2	2,347			2,349
Issuance of common stock under Associate Stock Purchase Plan (in shares)		172,000
Restricted stock, net		$ 24	(24)
Restricted stock, net (in shares)		2,396,000
Purchase of treasury stock	$ (9,640)	$ (8)	8	(9,640)		(9,640)
Purchase of treasury stock (in shares)	(750,000)	(750,000)
Shares withheld for employee taxes	$ (1,640)	$ (1)	(1,639)			(1,640)
Shares withheld for employee taxes (in shares)		(111,000)
Other	$ 287		137			137	150
Balances at end of period (in shares) at Dec. 31, 2016	190,045,681	190,046,000
Balances at end of period at Dec. 31, 2016	$ 2,077,732	$ 1,900	4,102,397	(56,440)	(1,969,875)	2,077,982	(250)
Compensation expense related to restricted stock grants	27,832		27,832			27,832
Net income (loss)	(571,606)				(571,419)	(571,419)	(187)
Issuance of common stock under Associate Stock Purchase Plan	$ 2,041	$ 2	2,039			2,041
Issuance of common stock under Associate Stock Purchase Plan (in shares)		181,000
Restricted stock, net		$ 14	(14)
Restricted stock, net (in shares)		1,421,000
Purchase of treasury stock (in shares)	0
Shares withheld for employee taxes	$ (5,889)	$ (3)	(5,886)			(5,889)
Shares withheld for employee taxes (in shares)		(372,000)
Other	$ 181		181			181
Balances at end of period (in shares) at Dec. 31, 2017	191,275,928	191,276,000
Balances at end of period at Dec. 31, 2017	$ 1,530,291	$ 1,913	$ 4,126,549	$ (56,440)	$ (2,541,294)	$ 1,530,728	$ (437)