Condensed Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Income Statement [Abstract]
Net sales	$ 262,476	$ 230,974	$ 745,345	$ 660,470
Cost of sales	142,591	117,499	401,779	342,985
Gross profit	119,885	113,475	343,566	317,485
Operating expenses:
Research and development and other engineering	8,679	10,932	35,051	33,807
Selling	28,156	24,304	86,150	74,313
General and administrative	36,501	32,543	108,049	96,786
Net gain on disposal of assets	(147)	(81)	(147)	(763)
Total operating expenses	73,189	67,698	229,103	204,143
Income from operations	46,696	45,777	114,463	113,342
Loss in equity method investment, before tax	(13)	0	(53)	0
Interest expense, net	(296)	(82)	(685)	(400)
Gain (adjustment) on bargain purchase of a business	(2,052)	0	6,336	0
Gain on disposal of a business	443	0	443	0
Income before taxes	44,778	45,695	120,504	112,942
Provision for income taxes	16,581	15,898	40,972	40,601
Net income	$ 28,197	$ 29,797	$ 79,532	$ 72,341
Earnings per common share:
Basic (in dollars per share)	$ 0.60	$ 0.62	$ 1.67	$ 1.50
Diluted (in dollars per share)	$ 0.59	$ 0.62	$ 1.66	$ 1.49
Number of shares outstanding
Basic (in shares)	47,367	48,119	47,544	48,231
Diluted (in shares)	47,686	48,352	47,843	48,429
Cash dividends declared per common share (in dollars per share)	$ 0.42	$ 0.18	$ 0.81	$ 0.52

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.