Consolidated Statements of Stockholders' Equity - 6 months ended Jun. 30, 2017 - 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]	Accumulated Foreign Currency Adjustment Attributable to Parent [Member]
Beginning Balance, Shares, Outstanding at Dec. 31, 2016		736,531,771
Beginning Balance, Equity at Dec. 31, 2016	$ 265,062	$ 74	$ 2,112,728		$ (1,099,010)	$ 58,052	$ 264,420	$ 642	$ 58,249
Beginning Balance, Treasury Stock, Shares at Dec. 31, 2016				(171,695,908)
Beginning Balance, Treasury Stock, Value at Dec. 31, 2016	(807,424)			$ (807,424)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative Effect on Retained Earnings, Net of Tax	(3,234)				(3,234)		(3,234)
Net loss	(27,161)				(33,740)		(33,740)	6,579
Foreign currency translation, net of tax	(22,225)					(22,225)		0	(22,225)
Other Comprehensive (Income) Loss, Amortization Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, for Net Prior Service Cost (Credit), Net of Tax	(2)							0
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax	(585)					(585)	(585)
Unrealized gain (loss) on available-for-sale debt security, net of tax	(2,054)					(2,054)	(2,054)
Exercise of stock options, shares		9,601
Exercise of stock options, value	19		19				19
Vesting of restricted stock units, shares		9,578,738
Vesting of restricted stock units, value		$ 0	0
Shares issued under employee stock purchase plan, shares		877,845
Shares issued under employee stock purchase plan, value	2,458		2,458				2,458
Tax withholding related to net share settlements of stock-based compensation awards, shares		(3,420,768)
Tax withholding related to net share settlements of stock-based compensation awards, value	(12,745)	$ 0	(12,745)				(12,745)
Stock-based compensation on equity-classified awards	42,570		42,570				42,570
Adjustments to Additional Paid in Capital, Equity Component of Convertible Debt			67,014
Purchases of treasury stock, shares				(14,522,134)
Purchases of treasury stock, value	(50,867)			$ (50,867)			(50,867)
Partnership distributions to noncontrolling interest holders	(6,426)							(6,426)
Ending Balance, Treasury Stock, Shares at Jun. 30, 2017				(186,218,042)
Ending Balance, Treasury Stock, Value at Jun. 30, 2017	(858,291)			$ (858,291)
Ending Balance, Shares, Outstanding at Jun. 30, 2017		743,577,187.000
Ending Balance, Equity at Jun. 30, 2017	$ 185,982	$ 74	$ 2,145,030		$ (1,135,984)	$ 34,358	$ 185,187	$ 795	$ 36,024