Consolidated Statements Of Stockholders' Equity (USD $) In Thousands	Common Stock [Member]	Additional Paid-In Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Gain/(Loss) [Member]	Treasury Stock [Member]	Total
Beginning Balance at Dec. 31, 2008	$ 374	$ 319,976	$ 159,470	$ 122	$ (67,959)	$ 411,983
Beginning Balance, shares at Dec. 31, 2008	37,392
Net income (loss)			76,928			76,928
Unrealized gain (loss) on available for sale securities, net of tax				235		235
Total comprehensive income (loss)						77,163
Exercise of stock options, value	1	717				718
Exercise of stock options, shares	71
Tax benefit from exercise of stock options		181				181
Tax benefit/deficiency related to the expiration of stock options		(1,237)				(1,237)
Tax benefit/deficiency related to the vesting of restricted stock		(606)				(606)
Employee stock purchase program		238				238
Purchase of treasury stock					(2,187)	(2,187)
Compensatory arrangements		13,737				13,737
Restricted stock grants, value	3	(3)
Restricted stock grants, shares	305
Forfeitures of restricted stock, value	(1)	1
Forfeitures of restricted stock, shares	(106)
Other		(1,337)				(1,337)
Ending Balance at Dec. 31, 2009	377	331,667	236,398	357	(70,146)	498,653
Ending Balance, shares at Dec. 31, 2009	37,662
Net income (loss)			92,731			92,731
Unrealized gain (loss) on available for sale securities, net of tax				(220)		(220)
Total comprehensive income (loss)						92,511
Exercise of stock options, value	11	24,783				24,794
Exercise of stock options, shares	1,111
Tax benefit from exercise of stock options		2,053				2,053
Tax benefit/deficiency related to the expiration of stock options		(351)				(351)
Tax benefit/deficiency related to the vesting of restricted stock		560				560
Resolution of tax contingencies		625				625
Employee stock purchase program		354				354
Purchase of treasury stock					(4,829)	(4,829)
Compensatory arrangements		14,074				14,074
Restricted stock grants, value	1	(1)
Restricted stock grants, shares	154
Forfeitures of restricted stock, shares	(54)
Ending Balance at Dec. 31, 2010	389	373,764	329,129	137	(74,975)	628,444
Ending Balance, shares at Dec. 31, 2010	38,873
Net income (loss)			(26,145)			(26,145)
Unrealized gain (loss) on available for sale securities, net of tax				(124)		(124)
Total comprehensive income (loss)						(26,269)
Exercise of stock options, value	7	10,343				10,350
Exercise of stock options, shares	668					668
Tax benefit from exercise of stock options						2,400
Tax benefit related to the expiration of stock options		(649)				(649)
Employee stock purchase program		333				333
Purchase of treasury stock					(8,004)	(8,004)
Compensatory arrangements		9,830				9,830
Cash settlement of share-based compensation		(4,133)				(4,133)
Restricted stock grants, value	1	(1)
Restricted stock grants, shares	170
Forfeitures of restricted stock, shares	(33)
Other		(321)				(321)
Ending Balance at Dec. 31, 2011	$ 397	$ 389,166	$ 302,984	$ 13	$ (82,979)	$ 609,581
Ending Balance, shares at Dec. 31, 2011	39,678