Stock Options - Activity (Details) - USD ($)	3 Months Ended	12 Months Ended	15 Months Ended
Sep. 30, 2021	Sep. 30, 2020	Jun. 30, 2021	Sep. 30, 2021
2012 Employee Stock Option Plan
Options
Outstanding, beginning of year	107,040	117,840	117,840	117,840
Granted	0	0
Exercised	(2,500)
Outstanding, end of period	104,540	117,840	107,040	104,540
Exercisable, end of period	48,988	37,400		48,988
Weighted average exercise price
Weighted average exercise price, bgn	$ 19.18	$ 18.84	$ 18.84	$ 18.84
Exercised (per share)	6.31
Weighted average exercise price, end	19.48	18.84	$ 19.18	19.48
Exercisable, end of period, weighted average exercise price	$ 16.95	$ 13.73		$ 16.95
Additional disclosures
Intrinsic value of options exercised	$ 94,000
Intrinsic value of options outstanding	2,467,000	$ 706,000		$ 2,467,000
Intrinsic value of options exercisable	$ 1,280,000	$ 399,000		$ 1,280,000
2012 Non-Employee Stock Option Plan
Options
Outstanding, beginning of year	6,000	12,000	12,000	12,000
Granted	0	0
Exercised	0	0
Outstanding, end of period	6,000	12,000	6,000	6,000
Exercisable, end of period	3,120	5,760		3,120
Weighted average exercise price
Weighted average exercise price, bgn	$ 13.10	$ 10.29	$ 10.29	$ 10.29
Exercised (per share)	0
Weighted average exercise price, end	13.10	10.29	$ 13.10	13.10
Exercisable, end of period, weighted average exercise price	$ 12.08	$ 8.35		$ 12.08
Additional disclosures
Intrinsic value of options outstanding	$ 180,000	$ 159,000		$ 180,000
Intrinsic value of options exercisable	$ 97,000	$ 87,000		$ 97,000
2018 Non-Employee Stock Option Plan
Options
Outstanding, beginning of year	35,050	48,400	48,400	48,400
Granted	0	0		0
Exercised	0			0
Outstanding, end of period	35,050	48,400	35,050	35,050
Exercisable, end of period	14,980	12,240		14,980
Weighted average exercise price
Weighted average exercise price, bgn	$ 23.85	$ 23.48	$ 23.48	$ 23.48
Weighted average exercise price, end	23.85	23.48	$ 23.85	23.85
Exercisable, end of period, weighted average exercise price	$ 23.36	$ 21.96		$ 23.36
Additional disclosures
Intrinsic value of options outstanding	$ 674,000	$ 114,000		$ 674,000
Intrinsic value of options exercisable	$ 295,000	$ 41,000		$ 295,000
2020 Non-Employee Stock Option Plan
Options
Outstanding, beginning of year	5,000
Granted	0	5,000
Exercised				0
Outstanding, end of period	5,000	5,000	5,000	5,000
Exercisable, end of period	2,000	1,000		2,000
Weighted average exercise price
Weighted average exercise price, bgn	$ 22.80
Granted (per share)		$ 22.80
Weighted average exercise price, end	22.80	22.80	$ 22.80	$ 22.80
Exercisable, end of period, weighted average exercise price	$ 22.80	22.80		$ 22.80
Additional disclosures
Weighted average fair value at grant date of options granted		$ 12.20
Intrinsic value of options outstanding	$ 101,000	$ 4,000		$ 101,000
Intrinsic value of options exercisable	$ 41,000	$ 1,000		$ 41,000

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