Fair Value Measurement - Reconciliation of Liabilities Using Level 3 (Details) - USD ($) $ in Thousands |
6 Months Ended | |
|---|---|---|
Jun. 30, 2019 |
Jun. 30, 2018 |
|
| Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | ||
| Payment of contingent consideration due to seller | $ 1,400 | $ 900 |
| Level 3 | ||
| Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | ||
| Balance at beginning of period | (2,960) | |
| Change in fair value of contingent consideration due to seller | (490) | |
| Payment of contingent consideration due to seller | 1,350 | |
| Balance at end of period | $ (2,100) | |