Business Combinations - Elixiter Acquisition (Details) - USD ($) $ in Thousands		12 Months Ended
	Oct. 29, 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
Elixiter
Business Acquisition [Line Items]
Cash paid for acquisition	$ 5,400
Common stock issued	1,400
Net working capital settlement	400
Initial fair value estimate of additional earnings-based contingent consideration	900
Period to realize additional earnings-based contingent consideration		12 months
Acquisition maximum payout		$ 1,800
Transaction costs		$ 500
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net [Abstract]
Acquired tangible assets	1,700
Identified intangible assets	2,600
Liabilities assumed	(2,000)
Goodwill	5,800
Total purchase price	$ 8,100