Consolidated Statements of Shareholders' Equity - USD ($) $ in Thousands	Total	Common Stock [Member]	Treasury [Member]	Additional Paid In Capital [Member]	Retained Earnings [Member]	Stock Options [Member]	Stock Options [Member] Additional Paid In Capital [Member]	Restricted Stock [Member]	Restricted Stock [Member] Additional Paid In Capital [Member]
Beginning Balance, shares at Dec. 31, 2013		62,753,000	220,000
Beginning Balance, value at Dec. 31, 2013	$ 518,433	$ 6,275	$ (1,895)	$ 456,812	$ 57,241
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(35,932)				(35,932)
Stock Issued During Period, Shares, Other		271,000
Exercise of options and related income tax effect, value	1,266	$ 27		1,239
Purchase of treasury stock, shares			(85,000)
Purchase of treasury stock, value	(631)		$ (631)
Income tax effect from share-based compensation, net						$ (56)	$ (56)	$ (265)	$ (265)
Issuance of restricted stock, shares		316,000
Issuance of restricted stock, value	0	$ 31		(31)
Stock-based compensation expense	6,371			6,371
Ending Balance, shares at Dec. 31, 2012		62,166,000	135,000
Ending Balance, value at Dec. 31, 2012	$ 547,680	$ 6,217	$ (1,264)	449,554	93,173
Beginning Balance, shares at Dec. 31, 2014	63,820,126	64,137,000	317,000
Beginning Balance, value at Dec. 31, 2014	$ 495,064	$ 6,414	$ (3,030)	472,457	19,223
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(38,018)				(38,018)
Stock Issued During Period, Shares, Other		929,000
Exercise of options and related income tax effect, value	8,368	$ 93		8,275
Purchase of treasury stock, shares			(97,000)
Purchase of treasury stock, value	(1,135)		$ (1,135)
Income tax effect from share-based compensation, net						(201)	(201)
Issuance of restricted stock, shares		455,000
Issuance of restricted stock, value	0	$ 46		(46)
Stock-based compensation expense	7,617			7,617
Ending Balance, shares at Dec. 31, 2013		62,753,000	220,000
Ending Balance, value at Dec. 31, 2013	$ 518,433	$ 6,275	$ (1,895)	456,812	57,241
Beginning Balance, shares at Dec. 31, 2015	64,497,915	64,956,000	458,000
Beginning Balance, value at Dec. 31, 2015	$ 342,643	$ 6,496	$ (3,759)	475,823	(135,917)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(155,140)				(155,140)
Stock Issued During Period, Shares, Other		203,000
Exercise of options and related income tax effect, value	781	$ 20		761
Purchase of treasury stock, shares			(141,000)
Purchase of treasury stock, value	(729)		$ (729)
Income tax effect from share-based compensation, net						$ (78)	$ (78)	$ (884)	$ (884)
Issuance of restricted stock, shares		616,000
Issuance of restricted stock, value	0	$ 62		(62)
Stock-based compensation expense	$ 3,629			3,629
Ending Balance, shares at Dec. 31, 2014	63,820,126	64,137,000	317,000
Ending Balance, value at Dec. 31, 2014	$ 495,064	$ 6,414	$ (3,030)	$ 472,457	$ 19,223