Consolidated Income Statements - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Statement [Abstract]
Gross Sales	$ 514,997	$ 525,936	$ 491,538
Commissions, allowances and rebates	1,018	1,995	2,369
Net sales	513,979	523,941	489,169
Other revenues, net	18,114	10,515	1,475
Net revenue	532,093	534,456	490,644
Cost of goods sold	335,405	304,153	286,256
Gross profit	196,688	230,303	204,388
Selling, general and administrative expenses	68,506	68,984	58,042
Research and development expenses	15,547	16,901	14,292
Acquisition and integration expenses	11,139		840
Restructuring expenses			1,158
Operating expenses	95,192	85,885	74,332
Operating profit	101,496	144,418	130,056
Other expenses/(income)
Interest expense, net	3,967	1,253	717
Unrealized gain on investment in equity securities	(13,023)
Other expenses, net	747	1,340	1,800
Income before income taxes	109,805	141,825	127,539
Provision for income taxes	16,596	38,061	40,214
Income from continuing operations	93,209	103,764	87,325
Loss from discontinued operations, net of tax	(791)	(1,314)	(5,647)
Net income	$ 92,418	$ 102,450	$ 81,678
Basic earnings per share
Income from continuing operations	$ 2.80	$ 3.18	$ 2.72
Loss from discontinued operations, net of tax	(0.02)	(0.04)	(0.17)
Net income	2.78	3.14	2.55
Diluted earnings per share
Income from continuing operations	2.77	3.10	2.65
Loss from discontinued operations, net of tax	(0.02)	(0.04)	(0.17)
Net income	$ 2.75	$ 3.06	$ 2.48
Weighted average shares outstanding:
Basic weighted average shares outstanding	33,243	32,662	32,086
Effect of dilutive stock based compensation	422	824	883
Diluted weighted average shares outstanding	33,665	33,486	32,969