Consolidated Statements of Stockholders' Equity - 9 months ended Sep. 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	(24,221)				(33,681)		(33,681)	9,460
Foreign currency translation, net of tax	(27,259)					(27,259)		0	(27,259)
Other Comprehensive (Income) Loss, Defined Benefit Plan, Prior Service Cost (Credit), Reclassification Adjustment from AOCI, after Tax	(2)							0
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax	(585)					(585)	(585)
Unrealized gain (loss) on available-for-sale debt security, net of tax	(2,279)					(2,279)	(2,279)
Exercise of stock options, shares		84,427
Exercise of stock options, value	203		203				203
Vesting of restricted stock units, shares		13,293,810
Vesting of restricted stock units, value		$ 1	(1)
Shares issued under employee stock purchase plan, shares		1,879,656
Shares issued under employee stock purchase plan, value	5,283		5,283				5,283
Tax withholding related to net share settlements of stock-based compensation awards, shares		(5,367,465)
Tax withholding related to net share settlements of stock-based compensation awards, value	(20,770)	$ 0	(20,770)				(20,770)
Stock-based compensation on equity-classified awards	63,696		63,696				63,696
Adjustments to Additional Paid in Capital, Equity Component of Convertible Debt			67,014
Purchases of treasury stock, shares				(16,906,334)
Purchases of treasury stock, value	(60,026)			$ (60,026)			(60,026)
Partnership distributions to noncontrolling interest holders	(8,974)							(8,974)
Ending Balance, Treasury Stock, Shares at Sep. 30, 2017				(188,602,242)
Ending Balance, Treasury Stock, Value at Sep. 30, 2017	(867,450)			$ (867,450)
Ending Balance, Shares, Outstanding at Sep. 30, 2017		746,422,199.000
Ending Balance, Equity at Sep. 30, 2017	$ 188,066	$ 75	$ 2,161,139		$ (1,135,925)	$ 29,099	$ 186,938	$ 1,128	$ 30,990