Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Statement [Abstract]
Net sales	$ 1,175,342	$ 876,737	$ 708,906
Cost of sales	799,231	600,961	486,774
Gross profit	376,111	275,776	222,132
Operating expenses:
Selling, general and administrative expenses	251,909	164,492	140,492
Research and development expenses	33,076	24,434	17,677
Impairment of intangible assets			6,568
Restructuring costs	4,449	4,143	9,849
Total operating expenses	289,434	193,069	174,586
Income from operations	86,677	82,707	47,546
Other non-operating income and expense:
Loss on partial settlement of pension plan	5,086	1,720
Interest expense, net	28,601	7,710	11,679
Loss on write-off of deferred financing and extinguishment of convertible debt	1,247	1,797	1,989
Other non-operating (income) expense, net	(5)	353	(7)
Total other non-operating (income) expense, net	34,929	11,580	13,661
Income before income taxes	51,748	71,127	33,885
Provision for income taxes	16,407	19,700	8,745
Net income	$ 35,341	$ 51,427	$ 25,140
Weighted average shares, basic	37,868	28,949	25,719
Weighted average shares, diluted	38,380	29,064	25,872
Net income per share:
Basic	$ 0.93	$ 1.78	$ 0.97
Diluted	0.92	1.77	0.97
Cash dividend declared per share	$ 0.68	$ 0.66	$ 0.60