CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY - USD ($) shares in Thousands, $ in Thousands	Total	Accumulated Deficit [Member]	AOCI Attributable to Parent [Member]	Common Stock [Member]	Additional Paid-In Capital [Member]	Treasury Stock [Member]
Beginning Balance at Dec. 31, 2013	$ 284,661	$ (539,597)	$ 0	$ 2,155	$ 822,103	$ 0
Beginning Balance (in shares) at Dec. 31, 2013				21,553		4
Net loss	(5,149)	(5,149)
Stock options exercised, net	1,289			$ 2	(2,716)	$ 4,003
Stock options exercised, net (in shares)				18		198
Issuance of restricted stock, net	98				(1,594)	$ 1,692
Issuance of restricted stock, net (in shares)						(79)
Stock-based compensation expense	1,935				1,935
Repurchase of common stock	(25,036)					$ (25,036)
Repurchase of common stock (in shares)						1,194
Other comprehensive loss	29				29
Conversion of convertible senior debentures to common stock (in shares)				2
Share of other comprehensive loss of equity method investments	0
Ending Balance at Dec. 31, 2014	257,827	(544,746)	0	$ 2,157	819,757	$ (19,341)
Ending Balance (in shares) at Dec. 31, 2014				21,573		921
Net loss	(59,524)	(59,524)
Stock options exercised, net	676				(1,051)	$ 1,727
Stock options exercised, net (in shares)						83
Issuance of restricted stock, net	158				(2,883)	$ 3,041
Issuance of restricted stock, net (in shares)						149
Stock-based compensation expense	1,611				1,611
Repurchase of common stock	(4,997)					$ (4,997)
Repurchase of common stock (in shares)						304
Share of other comprehensive loss of equity method investments	(246)		(246)
Ending Balance at Dec. 31, 2015	195,505	(604,270)	(246)	$ 2,157	817,434	$ (19,570)
Ending Balance (in shares) at Dec. 31, 2015				21,573		993
Net loss	(22,262)	(22,262)
Stock options exercised, net	(318)				(1,117)	$ 799
Stock options exercised, net (in shares)						46
Issuance of restricted stock, net	32				(3,067)	$ 3,099
Issuance of restricted stock, net (in shares)						162
Stock-based compensation expense	2,394				2,394
Repurchase of common stock	(5,389)					$ (5,389)
Repurchase of common stock (in shares)						424
Share of other comprehensive loss of equity method investments	(185)		(185)
Ending Balance at Dec. 31, 2016	$ 169,777	$ (626,904)	$ (431)	$ 2,157	$ 816,016	$ (21,061)
Ending Balance (in shares) at Dec. 31, 2016				21,573		1,209