CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Income Statement [Abstract]
Net sales	$ 302,293	$ 274,512
Cost of goods sold	189,882	175,917
Gross profit	112,411	98,595
Operating expenses
Selling, general and administrative	43,688	47,150
Research and development	22,170	20,200
Amortization of acquisition related intangible assets	4,484	4,767
Other operating income	(54)	(462)
Total operating expense	70,288	71,655
Income from operations	42,123	26,940
Other income (expense)
Interest income	875	514
Interest expense	(2,145)	(2,757)
Foreign currency loss, net	(64)	(3,029)
Other income	1,245	4,635
Total other expense	(89)	(637)
Income before income taxes and noncontrolling interest	42,034	26,303
Income tax provision	10,298	7,783
Net income	31,736	18,520
Less net (income) loss attributable to noncontrolling interest	(20)	6
Net income attributable to common stockholders	$ 31,716	$ 18,526
Earnings per share attributable to common stockholders:
Basic	$ 0.63	$ 0.38
Diluted	$ 0.62	$ 0.37
Number of shares used in earnings per share computation:
Basic	50,398	49,337
Diluted	51,462	50,622