Employee Benefits - Certain Information Regarding Health and Welfare Plan (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Change in Plan Assets:
Fair value of assets at end of year	$ 283,000
Post-Retirement Benefits
Change in benefit obligation:
Benefit obligation at beginning of year	12,000	$ 12,000
Interest cost	0	0	$ 0
Actuarial gain	(2,000)
Benefit obligation at end of year	10	12,000	$ 12,000
Change in Plan Assets:
Employer contribution		1,000
Premiums and claims paid		(1,000)
Funded status (included in “Other liabilities”)	(10,000)	(12,000)
Changes recognized in other comprehensive income for the year ended December 31:
Net actuarial (gain) loss arising during the year	2,000
Total recognized in other comprehensive income for the year (pre-tax)	$ 2,000
Accumulated other comprehensive loss (pre-tax) not yet recognized in net periodic benefit cost at December 31:
Actuarial loss, net		1,000
Total accumulated other comprehensive loss (pre-tax)		$ 1,000