Annual report pursuant to Section 13 and 15(d)

Selected Balance Sheet Data - Summary of Net Change in Carrying Value of Assets Held in Rabbi Trust and Deferred Compensation Liability (Detail)

v3.6.0.2
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
12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Balance Sheet Related Disclosures [Abstract]      
Increase (decrease) in the carrying value of the assets held in the rabbi trust $ 470 $ (57) $ 290
Increase (decrease) in the carrying value of the deferred compensation obligation $ 452 $ (67) $ 313