Selected Balance Sheet Data - Summary of Net Change in Carrying Value of Assets Held in Rabbi Trust and Deferred Compensation Liability (Detail) - USD ($) $ in Thousands |
3 Months Ended | 6 Months Ended | ||
|---|---|---|---|---|
Jun. 30, 2017 |
Jun. 30, 2016 |
Jun. 30, 2017 |
Jun. 30, 2016 |
|
| Balance Sheet Related Disclosures [Abstract] | ||||
| Increase in the carrying value of the assets held in the rabbi trust | $ 170 | $ 150 | $ 369 | $ 184 |
| Increase in the net carrying value of the deferred compensation obligation | $ 188 | $ 151 | $ 399 | $ 188 |
| X | ||||||||||
- Definition The amount of increase or decrease in the fair value of plan assets during the reporting period. No definition available.
|
| X | ||||||||||
- References No definition available.
|
| X | ||||||||||
- Definition The increase (decrease) during the reporting period in the obligation created by employee agreements whereby earned compensation will be paid in the future. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|