Summary of Stock Options Outstanding and Exercisable (Details) - $ / shares	12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Options Outstanding Shares	91,100	165,600	190,100
Options Outstanding, Weighted Average Remaining Term	5 years 6 months
Options Outstanding Weighted Average Exercise Price	$ 17.66	$ 19.15	$ 17.81
Range One
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Range of Exercise Prices	$ 14.87
Options Outstanding Shares	52,300
Options Outstanding, Weighted Average Remaining Term	5 years 1 month 6 days
Options Outstanding Weighted Average Exercise Price	$ 14.87
Range Two
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Range of Exercise Prices	$ 21.42
Options Outstanding Shares	38,800
Options Outstanding, Weighted Average Remaining Term	6 years 1 month 6 days
Options Outstanding Weighted Average Exercise Price	$ 21.42