Fair Value Measurements - Rollforward of the Fair Value as Determined by Level 3 (Detail) - USD ($) $ in Thousands |
12 Months Ended | |
|---|---|---|
Dec. 31, 2014 |
Dec. 31, 2013 |
|
| Fair Value Disclosures [Abstract] | ||
| Beginning balance | $ 99 | |
| Additions | $ 42 | |
| Payments | (237) | |
| Change in fair value included in earnings | $ 138 | 57 |
| Ending balance | $ 99 | |