Consolidated Statements of Operations (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Consolidated Statements of Operations
Net sales	$ 657,236	$ 603,446	$ 555,487
Cost of sales	373,759	332,642	311,349
Gross profit	283,477	270,804	244,138
Operating expenses:
Research and development and other engineering	35,919	25,886	21,110
Selling	82,364	73,568	63,293
General and administrative	100,973	95,820	79,788
Impairment of goodwill	2,346	1,282	6,292
Loss (gain) on sale of assets	166	191	(4,769)
Total operating expenses	221,768	196,747	165,714
Income from continuing operations	61,709	74,057	78,424
Income (loss) in equity method investment, before tax		4,389	(535)
Interest income	1,005	913	492
Interest expense	(793)	(573)	(344)
Income from continuing operations before taxes	61,921	78,786	78,037
Provision for income taxes from continuing operations	20,003	27,886	33,239
Income from continuing operations, net of tax	41,918	50,900	44,798
Loss from discontinued operations, net of tax			(16,212)
Net income	$ 41,918	$ 50,900	$ 28,586
Basic
Continuing operations (in dollars per share)	$ 0.87	$ 1.04	$ 0.91
Discontinued operations (in dollars per share)			$ (0.33)
Net income (in dollars per share)	$ 0.87	$ 1.04	$ 0.58
Diluted
Continuing operations (in dollars per share)	$ 0.87	$ 1.04	$ 0.90
Discontinued operations (in dollars per share)			$ (0.33)
Net income (in dollars per share)	$ 0.87	$ 1.04	$ 0.58
Weighted average number of shares outstanding
Basic (in shares)	48,339	48,974	49,498
Diluted (in shares)	48,412	49,023	49,612