Gross Reserves for Asbestos and Environmental Losses (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Insurance [Abstract]
Gross reserve for A&E losses and loss adjustment expenses – beginning of period	$ 47,593	$ 48,825	$ 50,445
Plus: Change in incurred losses and loss adjustment expenses	(7,500)	(259)	(2)
Less: Payments	940	973	1,618
Gross reserves for A&E losses and loss adjustment expenses – end of period	$ 39,153	$ 47,593	$ 48,825