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, 2010	$ 330,532	$ 15,841	$ 33,194	$ 295,044	$ (13,547)
Net income (loss):	37,055			37,055
Other comprehensive income (loss):	(49,255)				(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):	4,994				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)
Net income (loss):	37,761			37,761
Other comprehensive income (loss):	46,358				46,358
Stock options exercised	32,426	859	31,567
Stock issued to directors	0	15	(15)
Shares issued for employees stock purchase plan	734	24	710
Shares issued for restricted stock	(1,297)	53	(1,350)
Stock-based compensation expense	5,393		5,393
Ending Balance at Dec. 31, 2013	$ 555,527	$ 17,855	$ 110,577	$ 438,545	$ (11,450)