CONSOLIDATED STATEMENTS OF EQUITY - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-In- Capital	Treasury Stock	Accumulated Deficit	Noncontrolling Interest
Balances at beginning of period at Dec. 31, 2016	$ 2,077,732	$ 1,900	$ 4,102,397	$ (56,440)	$ (1,969,875)	$ (250)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock under Associate Stock Purchase Plan		2	2,039
Restricted stock, net		14	(14)
Shares withheld for employee taxes		(3)	(5,886)
Other, net		0	181		0
Compensation expense related to restricted stock grants			27,832
Purchase of treasury stock				0
Net income (loss)	(571,606)				(571,419)	(187)
Noncontrolling interest contribution						0
Noncontrolling interest distribution						0
Balances at end of period at Dec. 31, 2017	$ 1,530,291	$ 1,913	4,126,549	(56,440)	(2,541,294)	(437)
Balances at beginning of period (in shares) at Dec. 31, 2016		190,046,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock under Associate Stock Purchase Plan (in shares)		181,000
Restricted stock, net (in shares)		1,421,000
Purchase of treasury stock (in shares)	0	0
Shares withheld for employee taxes (in shares)		(372,000)
Balances at end of period (in shares) at Dec. 31, 2017		191,276,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock under Associate Stock Purchase Plan		$ 1	1,468
Restricted stock, net		26	(26)
Shares withheld for employee taxes		(4)	(3,057)
Other, net		32	146		280
Compensation expense related to restricted stock grants			26,067
Purchase of treasury stock	$ (8,500)			(8,500)
Net income (loss)	(528,352)				(528,258)	(94)
Noncontrolling interest contribution						41
Noncontrolling interest distribution						0
Balances at end of period at Dec. 31, 2018	$ 1,018,413	$ 1,968	4,151,147	(64,940)	(3,069,272)	(490)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock under Associate Stock Purchase Plan (in shares)		207,000
Restricted stock, net (in shares)		2,593,000
Purchase of treasury stock (in shares)	(1,280,802)	(1,281,000)
Shares withheld for employee taxes (in shares)		(439,000)
Balances at end of period (in shares) at Dec. 31, 2018	192,356,051	192,356,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock under Associate Stock Purchase Plan		$ 2	1,160
Restricted stock, net		31	(31)
Shares withheld for employee taxes		(5)	(3,308)
Other, net		0	105		0
Compensation expense related to restricted stock grants			23,026
Purchase of treasury stock	$ (19,700)			(19,711)
Net income (loss)	(268,492)				(267,931)	(561)
Noncontrolling interest contribution						6,566
Noncontrolling interest distribution						(3,146)
Balances at end of period at Dec. 31, 2019	$ 698,725	$ 1,996	$ 4,172,099	$ (84,651)	$ (3,393,088)	$ 2,369
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock under Associate Stock Purchase Plan (in shares)		181,000
Restricted stock, net (in shares)		3,073,000
Purchase of treasury stock (in shares)	(3,005,554)	(3,005,000)
Shares withheld for employee taxes (in shares)		(476,000)
Balances at end of period (in shares) at Dec. 31, 2019	192,128,586	192,129,000