Schedule I - Condensed Statements of Comprehensive Income (Parent Company Only) (Parenthetical) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Tax expense (benefit) on actuarial gain (loss), employee benefit plans	$ 13,263	$ (1,431)	$ (9,236)
Tax expense, adjustment for items reclassified to earnings, employee benefit plans	1,609	1,476	1,167
Parent Company [Member]
Tax expense (benefit) on actuarial gain (loss), employee benefit plans	13,263	(1,431)	(9,236)
Tax expense, adjustment for items reclassified to earnings, employee benefit plans	$ 1,609	$ 1,476	$ 1,167