CONDENSED 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 (in shares) at Dec. 31, 2017		191,276,000
Balances at beginning of period at Dec. 31, 2017	$ 1,530,291	$ 1,913	$ 4,126,549	$ (56,440)	$ (2,541,294)	$ 1,530,728	$ (437)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Compensation expense related to restricted stock grants	8,406		8,406			8,406
Net income (loss)	(457,234)				(457,188)	(457,188)	(46)
Issuance of common stock under Associate Stock Purchase Plan (in shares)		62,000
Issuance of common stock under Associate Stock Purchase Plan	372	$ 1	371			372
Restricted stock, net (in shares)		2,841,000
Restricted stock, net		$ 28	(28)
Shares withheld for employee taxes (in shares)		(381,000)
Shares withheld for employee taxes	(2,618)	$ (4)	(2,614)			(2,618)
Other, net	344		63		281	344
Balances at end of period at Mar. 31, 2018	$ 1,079,561	$ 1,938	4,132,747	(56,440)	(2,998,201)	1,080,044	(483)
Balances at end of period (in shares) at Mar. 31, 2018		193,798,000
Balances at beginning of period (in shares) at Dec. 31, 2018	192,356,051	192,356,000
Balances at beginning of period at Dec. 31, 2018	$ 1,018,413	$ 1,968	4,151,147	(64,940)	(3,069,272)	1,018,903	(490)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Compensation expense related to restricted stock grants	6,356		6,356			6,356
Net income (loss)	(42,606)				(42,595)	(42,595)	(11)
Issuance of common stock under Associate Stock Purchase Plan (in shares)		50,000
Issuance of common stock under Associate Stock Purchase Plan	299	$ 1	298			299
Restricted stock, net (in shares)		3,534,000
Restricted stock, net		$ 35	(35)
Purchase of treasury stock (in shares)		(933,000)
Purchase of treasury stock	(6,000)			(6,000)		(6,000)
Shares withheld for employee taxes (in shares)		(434,000)
Shares withheld for employee taxes	(2,997)	$ (4)	(2,993)			(2,997)
Other, net	17		17		0	17
Balances at end of period at Mar. 31, 2019	$ 917,597	$ 2,000	$ 4,154,790	$ (70,940)	$ (3,167,752)	$ 918,098	$ (501)
Balances at end of period (in shares) at Mar. 31, 2019	194,573,086	194,573,000