Consolidated Balance Sheet (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2021	Sep. 30, 2020
Statement Of Financial Position [Abstract]
Allowance for loan losses	$ 18,113	$ 15,400
Preferred Stock, par value	$ 0.01	$ 0.01
Preferred Stock, shares authorized	10,000,000	10,000,000
Preferred Stock, shares issued	0	0
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	40,000,000	40,000,000
Common stock, shares issued	18,133,095	18,133,095
Common stock, shares outstanding	10,461,443	10,876,869
Treasury stock, shares outstanding	7,671,652	7,256,226