Capital Stock (Detail) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020
Capital Stock
Common shares as presented in the accompanying Consolidated Balance Sheets	30,707,748	30,666,173
Common shares in treasury	4,854,997	4,604,741
Board of Directors authorized an expanded stock repurchase program	$ 200.0
Stock repurchases during period, shares	257,500	0	0
Stock Repurchased During Period, Value	$ 20.0