Condensed Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Income Statement [Abstract]
Net sales	$ 230,974	$ 216,139	$ 660,470	$ 609,295
Cost of sales	117,499	115,798	342,985	333,138
Gross profit	113,475	100,341	317,485	276,157
Operating expenses:
Research and development and other engineering	10,932	13,935	33,807	34,648
Selling	24,304	22,535	74,313	68,156
General and administrative	32,543	28,648	96,786	86,875
Net gain on disposal of assets	(81)	(26)	(763)	(57)
Total operating expenses	67,698	65,092	204,143	189,622
Income from operations	45,777	35,249	113,342	86,535
Interest expense, net	(82)	(175)	(400)	(264)
Income before taxes	45,695	35,074	112,942	86,271
Provision for income taxes	15,898	13,479	40,601	33,115
Net income	$ 29,797	$ 21,595	$ 72,341	$ 53,156
Earnings per common share:
Basic (in dollars per share)	$ 0.62	$ 0.44	$ 1.50	$ 1.08
Diluted (in dollars per share)	$ 0.62	$ 0.44	$ 1.49	$ 1.08
Number of shares outstanding
Basic (in shares)	48,119	48,998	48,231	49,157
Diluted (in shares)	48,352	49,239	48,429	49,377
Cash dividends declared per common share (in dollars per share)	$ 0.18	$ 0.16	$ 0.52	$ 0.460

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.