Consolidated Income Statements (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Income Statement [Abstract]
Gross sales	$ 139,130	$ 103,711
Commissions, allowances and rebates	209	594
Net sales	138,921	103,117
Other revenues, net	2,176	1,889
Net revenue	141,097	105,006
Cost of goods sold	90,242	58,131
Gross profit	50,855	46,875
Operating expenses:
Selling, general and administrative expenses	16,855	15,391
Research and development expenses	3,619	3,890
Total operating expenses	20,474	19,281
Operating profit	30,381	27,594
Other expenses:
Interest expense, net	82	266
Other expenses, net	264	401
Income before income taxes	30,035	26,927
Provision for income taxes	5,786	5,812
Income from continuing operations	24,249	21,115
Loss from discontinued operations, net of tax	(191)	(1,250)
Net income	$ 24,058	$ 19,865
Basic earnings/(loss) per share of common stock:
Income from continuing operations	$ 0.74	$ 0.65
Loss from discontinued operations, net of tax	(0.01)	(0.04)
Net income	0.73	0.61
Diluted earnings/(loss) per share of common stock:
Income from continuing operations	0.72	0.63
Loss from discontinued operations, net of tax	0.00	(0.03)
Net income	$ 0.72	$ 0.60
Weighted average shares outstanding:
Basic	32,894	32,454
Effect of dilutive stock based compensation	727	911
Diluted	33,621	33,365