Business Combinations - Stone Temple Acquisition (Details) - USD ($) $ in Thousands		12 Months Ended
	Jul. 16, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Business Acquisition [Line Items]
Period to realize additional earnings-based contingent consideration		12 months
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net [Abstract]
Goodwill		$ 327,992	$ 305,238	$ 275,205
Stone Temple
Business Acquisition [Line Items]
Cash paid for acquisition	$ 9,900
Common stock issued	1,100
Net working capital settlement	100
Initial fair value estimate of additional earnings-based contingent consideration	1,200
Acquisition maximum payout		2,600
Transaction costs		500
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net [Abstract]
Acquired tangible assets	2,500
Identified intangible assets	4,500
Liabilities assumed	(1,600)
Goodwill	6,900
Total purchase price	$ 12,300
Tax deductible amount of Goodwill		$ 5,400