Condensed Consolidated Statements of Operations (USD $) In Thousands, except Per 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	$ 207,893	$ 195,348	$ 376,198	$ 349,628
Cost of sales	111,993	106,176	202,518	195,736
Gross profit	95,900	89,172	173,680	153,892
Operating expenses:
Research and development and other engineering	10,094	9,484	19,794	17,792
Selling	24,213	21,652	46,032	43,024
General and administrative	29,494	28,347	56,435	54,382
Loss (gain) on sale of assets	(34)	11	(319)	3
Total operating expenses	63,767	59,494	121,942	115,201
Income from operations	32,133	29,678	51,738	38,691
Interest (expense) income, net	(15)	1	71	40
Income before taxes	32,118	29,679	51,809	38,731
Provision for income taxes	11,667	11,177	19,271	15,434
Net income	$ 20,451	$ 18,502	$ 32,538	$ 23,297
Earnings per common share:
Basic (in dollars per share)	$ 0.42	$ 0.38	$ 0.66	$ 0.48
Diluted (in dollars per share)	$ 0.42	$ 0.38	$ 0.66	$ 0.48
Number of shares outstanding
Basic (in shares)	49,011	48,529	48,955	48,532
Diluted (in shares)	49,227	48,628	49,146	48,627
Cash dividends declared per common share (in dollars per share)	$ 0.140	$ 0.125	$ 0.265	$ 0.125

The aggregate costs incurred (1) in a planned search or critical investigation aimed at discovery of new knowledge with the hope that such knowledge will be useful in developing a new product or service, a new process or technique, or in bringing about a significant improvement to an existing product or process; (2) to translate research findings or other knowledge into a plan or design for a new product or process or for a significant improvement to an existing product or process whether intended for sale or the entity's use, during the reporting period charged to research and development projects, including the costs of developing computer software up to the point in time of achieving technological feasibility, and costs allocated in accounting for a business combination to in-process projects deemed to have no alternative future use; (3) to conduct internal product testing; (4) or to provide engineering support to customers in the form of testing services or product uses, specifications or requirements.

No definition available.