Business Segments - EBITDA and Adjusted EBITDA (Details) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended									12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Segment Reporting Information [Line Items]
Net (loss) income	$ (29,251)	$ (44,937)	$ (299)	$ (1,684)	$ (738)	$ 7,116	$ 4,374	$ 5,678
Provision (benefit) for income tax										$ (461)	$ 11,288	$ 10,834
Depreciation, Depletion and Amortization, Nonproduction										(12,988)	(13,390)	(17,916)
Stock-based compensation										(5,302)	(6,820)	(5,572)
Change in fair value of contingent consideration liability										0	(677)	(10,417)
Inventory Write-down										(950)	0	0
Professional fees related to ASC 606										(1,092)	(829)	0
Goodwill impairment charge		(27,900)								(46,319)	0	0
Impairment of Intangible Assets (Excluding Goodwill)										(18,121)
Intangible asset impairment charges		$ (13,800)							$ (100)	(18,121)	0	(70)
Restructuring charges										(6,031)	0	(5,615)
Senior leadership transition and other employee-related costs										(1,410)	0	0
Business Development										0	715	0
Secured asset reserve										$ (433)	$ 0	$ 0
Weighted Average Number of Shares Outstanding, Diluted										52,230	54,944	54,460
Professional fees related to ASC 606 implementation										$ 507	$ 0	$ 0
Executive Succession Search Costs										(235)	(454)	0
professional fees related to restatement										(2,430)	0	0
Czech Koruna Appreciation Impact on Gross Profit										0	(860)	0
CEO search costs										9,147	6,420	4,239
Income (loss) before income taxes										(76,632)	27,718	14,783
Interest income										(218)	(97)	(86)
Interest expense										(7,749)	(4,729)	(4,171)
Other Nonoperating Income (Expense)										1,616	1,788	154
Adjusted EBITDA										27,900	57,883	58,612
Retained Earnings
Segment Reporting Information [Line Items]
Net (loss) income										$ (76,171)	$ 16,430	$ 3,949