Nature of Operations and Summary of Significant Accounting Policies - Basic and Diluted EPS (Detail) - USD ($)	12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Earnings Per Share [Abstract]
Net income (loss)	$ 5,531,000	$ 10,196,000
Net Income Diluted	$ 5,531,000	$ 10,196,000
Weighted average common shares outstanding	14,595,000	14,551,000
Common Stock Equivalents	125,000	157,000
Diluted shares outstanding	14,720,000	14,708,000
Basic earnings per common share:
Basic earnings per share	$ 0.38	$ 0.70
Diluted earnings per common share:
Diluted earnings per share	$ 0.38	$ 0.69