Summary of Stock Options Outstanding and Exercisable (Details) - USD ($)	12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Options Outstanding Shares	165,600	190,100	201,800
Options Outstanding, Weighted Average Remaining Term	4 years 10 months 24 days
Options Outstanding Weighted Average Exercise Price	$ 19.15	$ 17.81	$ 17.47
Options Outstanding Intrinsic Value	$ 34,650
Options Exercisable Shares	45,000
Option Exercisable Weighted Average Remaining Term	6 months
Options Exercisable Weighted Average Exercise Price	$ 23.16
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	69,300
Options Outstanding, Weighted Average Remaining Term	6 years 1 month 6 days
Options Outstanding Weighted Average Exercise Price	$ 14.87
Options Outstanding Intrinsic Value	$ 34,650
Range Two
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Range of Exercise Prices Minimum	$ 21.42
Range of Exercise Prices Maximum	$ 21.95
Options Outstanding Shares	84,300
Options Outstanding, Weighted Average Remaining Term	4 years 6 months
Options Outstanding Weighted Average Exercise Price	$ 21.63
Options Exercisable Shares	33,000
Option Exercisable Weighted Average Remaining Term	4 months 24 days
Options Exercisable Weighted Average Exercise Price	$ 21.95
Range Three
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Range of Exercise Prices Minimum	26.48
Range of Exercise Prices Maximum	$ 26.48
Options Outstanding Shares	12,000
Options Outstanding, Weighted Average Remaining Term	10 months 24 days
Options Outstanding Weighted Average Exercise Price	$ 26.48
Options Exercisable Shares	12,000
Option Exercisable Weighted Average Remaining Term	10 months 24 days
Options Exercisable Weighted Average Exercise Price	$ 26.48