Earning Per Share Data - Basic and Diluted Earnings Per Share (Detail) - USD ($)		3 Months Ended		9 Months Ended
		Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Earnings Per Share [Abstract]
Net income		$ 2,588,000	$ 2,114,000	$ 7,397,000	$ 5,319,000
Common Shares:
Weighted average common shares outstanding		14,400,000	14,333,000	14,390,000	14,321,000
Effect of dilutive stock options		299,000	217,000	290,000	170,000
Diluted shares outstanding		14,699,000	14,550,000	14,680,000	14,491,000
Basic:
Net earnings per share	[1]	$ 0.18	$ 0.15	$ 0.51	$ 0.37
Diluted:
Net earnings per share	[1]	$ 0.18	$ 0.15	$ 0.50	$ 0.37

[1] Prior year adjusted for three-for-two stock split