Consolidated Statements of Shareholders' Equity - USD ($) $ in Thousands	Total	Common Stock	Retained Earnings	Accumulated Other Comprehensive Loss
Beginning Balance (in shares) at Sep. 30, 2019		8,329,419
Beginning Balance at Sep. 30, 2019	$ 171,067	$ 43,030	$ 127,987	$ 50
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	24,269		24,269
Other comprehensive income	11			11
Repurchase of common stock (in shares)		(56,601)
Repurchase of common stock	$ (1,238)	$ (1,238)
Exercise of stock options (in shares)	37,975	37,975
Exercise of stock options	$ 391	$ 391
Common stock dividends	(7,083)		(7,083)
Earned Employee Stock Ownership Plan ("ESOP") shares, net of income taxes	31	31
Stock option compensation expense	182	182
Ending Balance at Sep. 30, 2020	187,630	$ 42,396	145,173	61
Ending Balance (in shares) at Sep. 30, 2020		8,310,793
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	27,583		27,583
Other comprehensive income	(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 income	(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