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)

v3.20.4
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, 2020
Dec. 31, 2019
Dec. 31, 2018
Balance Sheet Related Disclosures [Abstract]      
Increase (decrease) in the carrying value of the assets held in the rabbi trust $ 1,042 $ 1,353 $ (326)
Increase (decrease) in the net carrying value of the deferred compensation obligation $ 799 $ 1,293 $ (306)