Income Taxes - Current and Deferred Income Tax Expense (Detail) - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Deferred Income Tax Assets And Liabilities
Income before income taxes	$ 18,153	$ 19,002
Current income tax expense	6,765	6,687
Deferred income tax expense (benefit)	(1,591)	(1,224)
Total income tax expense	$ 5,174	$ 5,463