Fair Value Measurement (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Contingent Earn-out Liability	$ 17,300	$ 47,400	$ 27,000	$ 0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Issuances	17,300	0	19,000
Fair Value, Liability, Recurring Basis, Still Held, Unrealized Gain (Loss)	$ (47,400)	$ 20,400	$ 8,000