XML 109 R50.htm IDEA: XBRL DOCUMENT v3.20.4
Pension Plans - Accumulated Benefit Obligations in Excess of Plan Assets (Detail) - USD ($)
$ in Thousands
Dec. 31, 2020
Dec. 31, 2019
Defined Benefit Plan Plans With Benefit Obligations In Excess Of Plan Assets [Abstract]    
Accumulated benefit obligation $ 42,582 $ 37,936
Fair market value of assets $ 36,756 $ 32,658