Fair Value of Financial Measurements - Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) - Fair Value, Measurements, Recurring - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Level 1
Liabilities:
Contingent consideration	$ 0	$ 0
Total	0	0
Level 2
Liabilities:
Contingent consideration	0	0
Total	0	0
Level 3
Liabilities:
Contingent consideration	1,988	5,531
Total	$ 1,988	$ 5,531