Fair Value Measurements - Reconciliation of Assets and Liabilities Measured Using Significant Unobservable Inputs (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value adjustment	$ 415	$ (55)	$ 345	$ 80
Measured on a recurring basis
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Balance at Beginning			5,070
Balance at Ending	5,415		5,415
Level 3 | Measured on a recurring basis
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Balance at Beginning			5,070
Fair value adjustment			345
Balance at Ending	$ 5,415		$ 5,415