Consolidated Statements of Shareholders' Equity - USD ($) $ in Thousands	Total	Common Stock	Retained Earnings	Accumulated Other Comprehensive Loss
Beginning Balance (in shares) at Sep. 30, 2020		8,310,793
Beginning Balance at Sep. 30, 2020	$ 187,630	$ 42,396	$ 145,173	$ 61
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	27,583		27,583
Other comprehensive loss	(2)			(2)
Repurchase of common stock (in shares)		(19,588)
Repurchase of common stock	$ (527)	$ (527)
Exercise of stock options (in shares)	64,264	64,264
Exercise of stock options	$ 631	$ 631
Common stock dividends	(8,589)		(8,589)
Stock option compensation expense	173	173
Ending Balance at Sep. 30, 2021	206,899	$ 42,673	164,167	59
Ending Balance (in shares) at Sep. 30, 2021		8,355,469
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	23,600		23,600
Other comprehensive loss	(776)			(776)
Repurchase of common stock (in shares)		(170,237)
Repurchase of common stock	$ (4,583)	$ (4,583)
Exercise of stock options (in shares)	36,720	36,720
Exercise of stock options	$ 415	$ 415
Common stock dividends	(7,232)		(7,232)
Stock option compensation expense	246	246
Ending Balance at Sep. 30, 2022	218,569	$ 38,751	180,535	(717)
Ending Balance (in shares) at Sep. 30, 2022		8,221,952
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	27,118		27,118
Other comprehensive loss	(367)			(367)
Repurchase of common stock (in shares)		(185,399)
Repurchase of common stock	$ (4,998)	$ (4,998)
Exercise of stock options (in shares)	42,635	42,635
Exercise of stock options	$ 698	$ 698
Common stock dividends	(8,267)		(8,267)
Stock option compensation expense	320	320
Ending Balance at Sep. 30, 2023	$ 233,073	$ 34,771	$ 199,386	$ (1,084)
Ending Balance (in shares) at Sep. 30, 2023		8,105,338