Consolidated Statements of Stockholders' Equity - 3 months ended Mar. 31, 2016 - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Treasury Stock [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income [Member]	Parent [Member]	Noncontrolling Interest [Member]	Total Equity [Member]	Accumulated Foreign Currency Adjustment Attributable to Parent [Member]
Beginning Balance, Shares, Outstanding at Dec. 31, 2015		719,787,422
Beginning Balance, Equity at Dec. 31, 2015	$ 470,587	$ 72	$ 1,964,453		$ (901,292)	$ 51,206	$ 469,398	$ 1,189	$ 470,587
Beginning Balance, Treasury Stock, Shares at Dec. 31, 2015				(128,468,165)
Beginning Balance, Treasury Stock, Value at Dec. 31, 2015	(645,041)			$ (645,041)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative Effect on Retained Earnings, Net of Tax					(3,131)		(3,131)		(3,131)
Net loss	$ (45,596)				(49,119)		(49,119)	3,523	(45,596)
Foreign currency translation, net of tax						(2,763)		0	(2,763)	$ (2,763)
Other Comprehensive (Income) Loss, Amortization Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, for Net Prior Service Cost (Credit), Net of Tax						27	27	0	27
Unrealized gain (loss) on available-for-sale debt security, net of tax						(116)	(116)		(116)
Issuance of unvested restricted stock	(196,968)
Exercise of stock options, shares		253,511
Exercise of stock options, value			319				319		319
Vesting of restricted stock units, shares		4,104,383
Vesting of restricted stock units, value		$ 0	0
Shares issued under employee stock purchase plan, shares		618,319
Shares issued under employee stock purchase plan, value			1,614				1,614		1,614
Tax withholding related to net share settlements of stock-based compensation awards, shares		(1,399,721)
Tax withholding related to net share settlements of stock-based compensation awards, value		$ 0	(4,262)				(4,262)		(4,262)
Stock-based compensation on equity-classified awards			35,806				35,806		35,806
Purchases of treasury stock, shares				(18,820,000)
Purchases of treasury stock, value				$ (63,449)			(63,449)		(63,449)
Partnership distributions to noncontrolling interest holders								(3,365)	(3,365)
Ending Balance, Treasury Stock, Shares at Mar. 31, 2016				(147,288,165)
Ending Balance, Treasury Stock, Value at Mar. 31, 2016	$ (708,490)			$ (708,490)
Ending Balance, Shares, Outstanding at Mar. 31, 2016		723,166,946
Ending Balance, Equity at Mar. 31, 2016	$ 385,671	$ 72	$ 1,997,930		$ (953,542)	$ 48,354	$ 384,324	$ 1,347	$ 385,671