Retirement Plans - Information Pertaining to Activity in Supplemental Retirement Plans (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Change in benefit obligation:
Benefit obligation at beginning of year	$ (38,000)	$ (36,737)
Service cost	(913)	(2,225)	$ (879)
Interest cost	(898)	(1,014)	(1,131)
Actuarial (loss)/gain	3,580	640
Plan amendments	0	0
Benefits paid	972	1,336
Benefit obligation at end of year	(35,259)	(38,000)	$ (36,737)
Change in plan assets:
Fair value of plan assets at beginning of year	0
Fair value of plan assets at end of year	0	0
Funded status	(35,259)	(38,000)
Unrecognized net obligation existing at January 1, 1986		0
Unrecognized net actuarial (loss)/gain	(2,453)	1,380
Unrecognized prior service cost	(28)	(86)
Accumulated other comprehensive income (loss)	2,481	(1,294)
Accrued benefit cost	(35,259)	(38,000)
Accumulated benefit obligation	$ (34,015)	$ (36,298)