CONDENSED CONSOLIDATED STATEMENT OF INCOME (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Income Statement [Abstract]
Net sales	$ 153,495	$ 132,452	$ 300,135	$ 258,432
Cost of sales	96,357	88,023	189,078	172,713
Gross margin	57,138	44,429	111,057	85,719
Selling and administrative expenses	34,499	25,547	62,097	50,753
Research and development expenses	6,420	6,250	11,283	11,519
Restructuring and impairment charges		4,525	0	4,525
Operating income	16,219	8,107	37,677	18,922
Equity income in unconsolidated joint ventures	1,062	762	2,039	1,291
Other income (expense), net	(76)	(177)	(1,268)	(766)
Interest income (expense), net	(720)	(830)	(1,468)	(1,735)
Income before income tax expense	16,485	7,862	36,980	17,712
Income tax expense	5,583	2,279	11,498	5,152
Income from continuing operations	10,902	5,583	25,482	12,560
Income (loss) from discontinued operations, net of income taxes	0	(18)	0	102
Net income	$ 10,902	$ 5,565	$ 25,482	$ 12,662
Basic net income per share:
Income from continuing operations (in dollars per share)	$ 0.60	$ 0.33	$ 1.41	$ 0.73
Income from discontinued operations (in dollars per share)		$ 0.00	$ 0.00	$ 0.01
Net income (loss) (in dollars per share)	$ 0.60	$ 0.33	$ 1.41	$ 0.74
Diluted net income per share:
Income from continuing operations (in dollars per share)	$ 0.58	$ 0.32	$ 1.37	$ 0.71
Income from discontinued operations (in dollars per share)		$ 0.00	$ 0.00	$ 0.01
Net income (in dollars per share)	$ 0.58	$ 0.32	$ 1.37	$ 0.72
Shares used in computing:
Basic net income per share (shares)	18,158,244	17,107,727	18,054,543	17,090,093
Diluted net income per share (shares)	18,688,538	17,599,481	18,618,998	17,636,440