Fair Value Measurement Fair Value Liabilities Measured on Recurring Basis, Unobservable Inputs (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Dec. 31, 2017	[1]
Fair Value Disclosures [Abstract]
Fair Value, Liabilities Measured on Recurring Basis, Change in Unrealized Gain (Loss)	$ 20,500
CONTINGENT EARN-OUT LIABILITY	$ 47,500	$ 27,000

[1] December 31, 2017 balances were derived from audited consolidated financial statements.