Business Segments - EBITDA and Adjusted EBITDA (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Segment Reporting [Abstract]
Adjusted EBITDA			$ 59,153	$ 50,799	$ 41,654
Depreciation and amortization			(17,916)	(17,472)	(17,723)
Stock-based compensation			(5,572)	(5,873)	(5,352)
Change in fair value of contingent consideration			(10,417)	270	37,873
Goodwill impairment charge			0	(37,539)	0
Intangible asset impairment charges	$ (100)	$ (200)	(70)	(202)	(2,710)
Restructuring and other charges			(5,615)	(1,053)	0
Secured asset reserve			0	(2,023)	(940)
Restatement-related professional fees			0	0	(2,093)
Interest income			(4,238)	(7,678)	(5,118)
Income (loss) before income taxes			$ 15,325	$ (20,771)	$ 45,591