Fair Value Measurements - Roll Forward of Fair Value of Contingent Obligations (Detail) - Contingent Obligations [Member] $ in Thousands |
9 Months Ended |
|---|---|
|
Sep. 30, 2016
USD ($)
| |
| Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | |
| Beginning balances | $ 1,000 |
| Change in fair value | (50) |
| Ending balances | $ 950 |