Condensed Consolidated Statements of Income (unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Condensed Consolidated Statements of Income (unaudited) [Abstract]
Net sales	$ 278,721	$ 288,748
Cost of sales	206,765	222,703
Gross profit	71,956	66,045
Selling, general, administrative and engineering expenses	43,806	43,804
Income from operations	28,150	22,241
Interest expense	467	297
Other income, net of expenses	544	1,761
Income from operations before income taxes	28,227	23,705
Income taxes	10,549	8,788
Net income	17,678	14,917
Net loss attributable to non-controlling interest	(65)	(188)
Net income attributable to controlling interest	$ 17,743	$ 15,105
Net income attributable to controlling interest:
Basic (in dollars per share)	$ 0.77	$ 0.66
Diluted (in dollars per share)	$ 0.77	$ 0.65
Weighted average number of common shares outstanding:
Basic (in shares)	22,965	22,904
Diluted (in shares)	23,135	23,114
Dividends declared per common share (in dollars per share)	$ 0.10	$ 0.10