Income Taxes - Provision for Income Tax Expense (Benefit) (Detail) - USD ($)	12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022
Current:
Federal	$ 4,151,000	$ 1,680,000
State	279,000	317,000
Total current	4,430,000	1,997,000
Deferred:
Federal	(328,000)	(2,701,000)
State	8,000	(617,000)
Total deferred	(320,000)	(3,318,000)
Income tax expense (benefit)	$ 4,110,000	$ (1,321,000)