Consolidated Income Statements - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Gross sales	$ 525,936	$ 491,538	$ 433,856
Commissions, allowances and rebates	1,995	2,369	1,949
Net sales	523,941	489,169	431,907
Other revenue, net	10,515	1,475	1,419
Net revenues	534,456	490,644	433,326
Cost of goods sold	304,369	286,419	256,361
Gross profit	230,087	204,225	176,965
Selling, general and administrative expenses	70,468	60,422	57,867
Research and development expenses	16,901	14,292	12,540
Restructuring expenses		1,158	15,573
Operating expenses	87,369	75,872	85,980
Operating profit	142,718	128,353	90,985
Other expenses/(income)
Interest expense, net	1,253	717	1,699
Other (income)/expense, net	(360)	97	(279)
Income before income taxes	141,825	127,539	89,565
Provision for income taxes	38,061	40,214	32,389
Income from continuing operations	103,764	87,325	57,176
(Loss)/income from discontinued operations, net of tax	(1,314)	(5,647)	41
Net income	$ 102,450	$ 81,678	$ 57,217
Basic earnings per share
Income from continuing operations (in dollars per share)	$ 3.18	$ 2.72	$ 1.82
(Loss)/income from discontinued operations, net of tax (in dollars per share)	(0.04)	(0.17)	0
Net income (in dollars per share)	3.14	2.55	1.82
Diluted earnings per share
Income from continuing operations (in dollars per share)	3.10	2.65	1.76
(Loss)/income from discontinued operations, net of tax (in dollars per share)	(0.04)	(0.17)	0
Net income (in dollars per share)	$ 3.06	$ 2.48	$ 1.76
Weighted average shares outstanding:
Basic weighted average shares outstanding (in shares)	32,662	32,086	31,420
Effect of dilutive stock based compensation (in shares)	824	883	1,135
Diluted weighted average shares outstanding (in shares)	33,486	32,969	32,555