CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY AND COMPREHENSIVE INCOME (USD $) In Thousands, except Share data, unless otherwise specified	Common Stock [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Total
Balance at Dec. 31, 2008	$ 163,550	$ 461,741	$ 13,703	$ 638,994
Balance (in shares) at Dec. 31, 2008	25,830,374
Comprehensive income:
Net income	0	8,515	0	8,515
Net unrealized gain (loss) on available-for-sale securities	0	0	3,612	3,612
Net change in pension liability	0	0	(936)	(936)
Cumulative translation adjustment	0	0	5,149	5,149
Total comprehensive income	0	0	0	16,340
Impact of repurchase of convertible debt	(829)			(829)
Issuance of common stock	944	0	0	944
Issuance of common stock (in shares)	129,131
Repurchases of common stock	(9,753)	0	0	(9,753)
Repurchases of common stock (in shares)	(567,000)
Exercise of stock options	33	0	0	33
Exercise of stock options (in shares)	8,500
Tax benefit (shortfall) from exercise of stock options	149	0	0	149
Stock based compensation	3,839	0	0	3,839
Balance at Dec. 31, 2009	157,933	470,256	21,528	649,717
Balance (in shares) at Dec. 31, 2009	25,401,005
Comprehensive income:
Net income	0	29,276	0	29,276
Net unrealized gain (loss) on available-for-sale securities	0	0	79	79
Net change in pension liability	0	0	(782)	(782)
Cumulative translation adjustment	0	0	(10,368)	(10,368)
Total comprehensive income	0	0	0	18,205
Issuance of common stock	319	0	0	319
Issuance of common stock (in shares)	140,755
Repurchases of common stock	(19,766)	0	0	(19,766)
Repurchases of common stock (in shares)	(854,134)
Exercise of stock options	362	0	0	362
Exercise of stock options (in shares)	25,500
Tax benefit (shortfall) from exercise of stock options	(472)	0	0	(472)
Stock based compensation	3,844	0	0	3,844
Balance at Dec. 31, 2010	142,220	499,532	10,457	652,209
Balance (in shares) at Dec. 31, 2010	24,713,126
Comprehensive income:
Net income	0	83,888	0	83,888
Net unrealized gain (loss) on available-for-sale securities	0	0	(3,035)	(3,035)
Net change in pension liability	0	0	(1,591)	(1,591)
Cumulative translation adjustment	0	0	(2,735)	(2,735)
Total comprehensive income	0	0	0	76,527
Issuance of common stock	851	0	0	851
Issuance of common stock (in shares)	304,859
Repurchases of common stock	(25,775)	0	0	(25,775)
Repurchases of common stock (in shares)	(842,934)
Tax benefit (shortfall) from exercise of stock options	740	0	0	740
Stock based compensation	4,146	0	0	4,146
Balance at Dec. 31, 2011	$ 122,182	$ 583,420	$ 3,096	$ 708,698
Balance (in shares) at Dec. 31, 2011	24,175,051