Consolidated Statements of Income (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Consolidated Statements of Income [Abstract]
Net sales	$ 955,729	$ 771,335	$ 738,094
Cost of sales	736,935	592,288	585,667
Gross profit	218,794	179,047	152,427
Selling, general and administrative expenses	138,845	114,141	107,455
Goodwill and other intangible asset impairment charges	0	0	17,036
Research and development expenses	22,422	17,482	18,029
Income from operations	57,527	47,424	9,907
Other income:
Interest expense	193	352	537
Interest income	883	956	734
Other income (expense), net	1,084	675	1,137
Income before income taxes	59,301	48,703	11,241
Income taxes	19,281	16,131	8,135
Net income	40,020	32,572	3,106
Net income attributable to non-controlling interest	102	142	38
Net income attributable to controlling interest	$ 39,918	$ 32,430	$ 3,068
Net income attributable to controlling interest:
Basic (in dollars per share)	$ 1.77	$ 1.44	$ 0.14
Diluted (in dollars per share)	$ 1.74	$ 1.42	$ 0.14
Weighted average number of common shares outstanding:
Basic (in shares)	22,588,721	22,517,246	22,446,940
Diluted (in shares)	22,984,221	22,829,799	22,715,780