Condensed Consolidated Statements of Changes in Equity Statement - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Treasury Stock	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit	Total Equity	Non-controlling interest
Beginning balance (in shares) at Dec. 31, 2016		397,979,772		2,282,700
Beginning balance at Dec. 31, 2016	$ 975,770	$ 4,003	$ 1,226,206	$ (19,485)	$ (767)	$ (234,187)	$ 975,770	$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation and related tax effects	22,056		23,453			(1,397)	22,056
Stock option exercises and other (in shares)		4,864,441
Stock option exercises and other	4,299	$ 48	4,251				4,299
Net unrealized gain on available for sale securities, net of tax	141				141		141
Net loss	(29,844)					(29,844)	(29,844)
Net loss, including portion attributable to noncontrolling interest	(29,844)
Ending balance (in shares) at Mar. 31, 2017		402,844,213		2,282,700
Ending balance at Mar. 31, 2017	972,422	$ 4,051	1,253,910	$ (19,485)	(626)	(265,428)	972,422	0
Beginning balance (in shares) at Dec. 31, 2017		417,473,846		2,282,700
Beginning balance at Dec. 31, 2017	927,757	$ 4,198	1,327,206	$ (19,485)	(5)	(389,419)	922,495	5,262
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation and related tax effects	20,024		20,024			0	20,024
Stock option exercises and other (in shares)		2,133,783
Stock option exercises and other	(439)	$ 21	(460)				(439)
Net unrealized gain on available for sale securities, net of tax	42				50		50	(8)
Dividends paid and return of capital to noncontrolling interests	(1,084)							(1,084)
Net loss	(31,181)					(31,181)	(31,181)	1
Net loss, including portion attributable to noncontrolling interest	(31,180)
Ending balance (in shares) at Mar. 31, 2018		419,607,629		2,282,700
Ending balance at Mar. 31, 2018	$ 915,120	$ 4,219	$ 1,346,770	$ (19,485)	$ 45	$ (420,600)	$ 910,949	$ 4,171