CONSOLIDATED STATEMENTS OF STOCKHOLDERS EQUITY (USD $) In Thousands	Total	Common Stock [Member]	Additional Paid-In Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]
Beginning Balance at Dec. 31, 2009	$ 292,950	$ 15,743	$ 25,160	$ 260,473	$ (8,426)
Net income (loss)	34,571			34,571
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	(5,121)
Stock options exercised	790	26	764
Stock issued to directors	28	38	(10)
Shares issued for employees stock purchase plan	686	34	652
Stock-based compensation expense	6,628		6,628
Ending Balance at Dec. 31, 2010	330,532	15,841	33,194	295,044	(13,547)
Net income (loss)	37,055			37,055
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	(49,255)
Stock options exercised	11,071	330	10,741
Stock issued to directors	1	22	(21)
Shares issued for employees stock purchase plan	756	28	728
Stock-based compensation expense	8,096		8,096
Ending Balance at Dec. 31, 2011	338,256	16,221	52,738	332,099	(62,802)
Net income (loss)	68,685			68,685
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	4,994
Stock options exercised	17,007	603	16,404
Stock issued to directors	0	15	(15)
Shares issued for employees stock purchase plan	809	27	782
Shares issued for restricted stock	(752)	38	(790)
Stock-based compensation expense	5,153		5,153
Ending Balance at Dec. 31, 2012	$ 434,152	$ 16,904	$ 74,272	$ 400,784	$ (57,808)