Condensed Consolidated Statement of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Income Statement [Abstract]
Revenue	$ 288,386	$ 279,993	$ 835,306	$ 820,286
Cost of goods sold	215,867	212,212	628,282	625,465
Gross profit	72,519	67,781	207,024	194,821
Operating expenses:
Selling, general and administrative expenses	57,134	52,601	165,647	155,511
Depreciation and amortization	3,317	5,066	9,403	14,382
Change in fair value of contingent consideration	(167)	788	677	9,975
Restructuring and other charges	0	466	0	4,433
Income from operations	12,235	8,860	31,297	10,520
Other income (expense):
Interest income	31	26	77	63
Interest expense	(1,198)	(1,191)	(3,239)	(3,252)
Other, net	427	(114)	(962)	16
Total other expense	(740)	(1,279)	(4,123)	(3,173)
Income before income taxes	11,495	7,581	27,173	7,347
Income tax expense	3,967	3,240	9,694	8,023
Net income (loss)	$ 7,528	$ 4,341	$ 17,479	$ (676)
Basic earnings (loss) per share (in dollars per share)	$ 0.14	$ 0.08	$ 0.32	$ (0.01)
Diluted earnings (loss) per share (in dollars per share)	$ 0.14	$ 0.08	$ 0.32	$ (0.01)
Comprehensive income (loss)	$ 9,696	$ 4,676	$ 25,506	$ (2,201)