CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Income Statement [Abstract]
Net sales	$ 236,303	$ 222,738
Cost of goods sold	162,392	158,518
Gross profit	73,911	64,220
Operating expenses
Selling, general and administrative	39,690	39,454
Research and development	18,040	18,149
Amortization of acquisition related intangible assets	4,758	5,131
Restructuring expense	2,231
Other operating (income) expenses	(165)	31
Total operating expenses	64,554	62,765
Income from operations	9,357	1,455
Other income (expense)
Interest income	295	456
Interest expense	(3,485)	(2,512)
Currency, net	(3,794)	(1,279)
Other expense	(271)	(157)
Total other income (expense)	(7,255)	(3,492)
Income before income taxes and noncontrolling interest	2,102	(2,037)
Income tax provision (benefit)	560	(552)
Net income (loss)	1,542	(1,485)
Less net income attributable to noncontrolling interest	(325)	(248)
Net income (loss) attributable to common stockholders	$ 1,217	$ (1,733)
Earnings (loss) per share attributable to common stockholders:
Basic	$ 0.03	$ (0.04)
Diluted	$ 0.02	$ (0.04)
Number of shares used in earnings per share computation:
Basic	48,316	48,288
Diluted	49,663	48,288