Earnings per Share Data - Basic and Diluted Earnings Per Share (Detail) - USD ($)	3 Months Ended						9 Months Ended
	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Jun. 30, 2021	Jun. 30, 2020
Earnings Per Share [Abstract]
Net Income	$ 2,335,000	$ 2,288,000	$ 1,551,000	$ 4,322,000	$ (655,000)	$ 2,489,000	$ 6,174,000	$ 6,156,000
Common Shares:
Weighted average common shares outstanding	14,617,000			14,601,000			14,613,000	14,592,000
Effect of dilutive stock options	132,000			118,000			129,000	125,000
Diluted shares outstanding	14,749,000			14,719,000			14,742,000	14,717,000
Basic:
Net earnings per share	$ 0.16			$ 0.30			$ 0.42	$ 0.42
Diluted:
Net earnings per share	$ 0.16			$ 0.29			$ 0.42	$ 0.42