Fair Value Measurements - Changes in the earn-out, Level 3 (Details) - Recurring - Level 3 - USD ($) $ in Thousands	3 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at the beginning of the period	$ 3,610	$ 3,480	$ 11,100	$ 7,544	$ 7,075	$ 7,075
Payment of earn-out liability	0	0	(8,000)	0	0	0
Revaluations included in earnings	91	130	380	4,616	469	0
Balance at the end of the period	$ 3,701	$ 3,610	$ 3,480	$ 12,160	$ 7,544	$ 7,075