Components of Net Periodic Benefit Cost (Narrative) (Detail) - USD ($)			3 Months Ended
	Dec. 31, 2006	Dec. 31, 2002	Mar. 31, 2024
Retirement Benefits [Abstract]
Service period for employees of coverage age, years (at least)			1 year
Defined benefit plan, percentage vested			100.00%
Retiree benefits eliminated if less than service period, years (less than)	10 years	10 years
Defined benefit plan, contributions by employer			$ 0