Summary of Significant Accounting Policies - Other Expense (Income) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Accounting Policies [Abstract]
Foreign currency losses (gains)	$ 260	$ (33)	$ 557
Tax indemnification (income) expense, net	(2,218)	10,635	(2,855)
Interest income	(238)	(686)	(167)
Arbitration award	0	(3,453)	0
Other	(2)	(242)	0
Total other (income) loss	$ (2,198)	$ 6,221	$ (2,465)