Stock Option - Activity (Details) - USD ($)	3 Months Ended		6 Months Ended		12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2023	Dec. 31, 2022	Jun. 30, 2023
2012 Employee Stock Option Plan
Options
Outstanding, beginning of year			521,580	523,080	523,080
Granted	0	0	0	37,500
Forfeited/Lapsed			(11,000)
Exercised	(31,600)	(2,000)	(31,600)	(7,200)
Outstanding, end of period	478,980	553,380	478,980	553,380	521,580
Exercisable, end of period	289,728	262,252	289,728	262,252
Weighted average exercise price
Weighted average exercise price, beginning of year			$ 19.37	$ 18.59	$ 18.59
Granted (per share)				26.94
Forfeited/Lapsed (per share)			3.15
Exercised (per share)			22.13	7.07
Weighted average exercise price, end of period	$ 19.56	$ 18.90	19.56	18.90	$ 19.37
Exercisable, end of period, weighted average exercise price	$ 18.58	$ 16.88	$ 18.58	16.88
Additional disclosures
Weighted average fair value at grant date of options granted				$ 13.36
Total intrinsic value of options exercised			$ 375,000	$ 159,000
Total intrinsic value of options outstanding	$ 7,034,000	$ 4,746,000	7,034,000	4,746,000
Total intrinsic value of options exercisable	$ 4,539,000	$ 2,779,000	$ 4,539,000	$ 2,779,000
2012 Non-Employee Stock Option Plan
Options
Outstanding, beginning of year			20,400	20,400	20,400
Granted	0	0	0	0
Exercised	0	0	0	0
Outstanding, end of period	20,400	20,400	20,400	20,400	20,400
Exercisable, end of period	15,840	13,200	15,840	13,200
Weighted average exercise price
Weighted average exercise price, beginning of year			$ 14.39	$ 14.39	$ 14.39
Exercised (per share)			0
Weighted average exercise price, end of period	$ 14.39	$ 14.39	14.39	14.39	$ 14.39
Exercisable, end of period, weighted average exercise price	$ 12.44	$ 10.95	$ 12.44	$ 10.95
Additional disclosures
Total intrinsic value of options outstanding	$ 405,000	$ 267,000	$ 405,000	$ 267,000
Total intrinsic value of options exercisable	$ 345,000	$ 218,000	$ 345,000	$ 218,000
2018 Non-Employee Stock Option Plan
Options
Outstanding, beginning of year			75,000	89,000	89,000
Granted	0	0	0	0
Exercised	(1,600)	(3,600)	(1,600)	(9,900)
Outstanding, end of period	73,400	79,100	73,400	79,100	75,000
Exercisable, end of period	58,620	49,440	58,620	49,440
Weighted average exercise price
Weighted average exercise price, beginning of year			$ 14.83	$ 14.91	$ 14.91
Exercised (per share)			15.27	16.27
Weighted average exercise price, end of period	$ 14.82	$ 14.74	14.82	14.74	$ 14.83
Exercisable, end of period, weighted average exercise price	$ 13.81	$ 13.02	$ 13.81	$ 13.02
Additional disclosures
Total intrinsic value of options exercised			$ 28,000	$ 124,000
Total intrinsic value of options outstanding	$ 1,426,000	$ 1,008,000	1,426,000	1,008,000
Total intrinsic value of options exercisable	$ 1,198,000	$ 715,000	$ 1,198,000	$ 715,000
2020 Non-Employee Stock Option Plan
Options
Granted	0	0	0	25,000
Outstanding, end of period	56,900		56,900
Exercisable, end of period	29,140		29,140
2022 Employee Stock Option Plan
Options
Outstanding, beginning of year			5,000
Granted	10,000		10,000
Forfeited/Lapsed			(5,000)
Exercised	0		0
Outstanding, end of period	10,000		10,000		5,000
Exercisable, end of period	2,000		2,000
Weighted average exercise price
Weighted average exercise price, beginning of year			$ 40.01
Granted (per share)			21.60
Forfeited/Lapsed (per share)			40.01
Weighted average exercise price, end of period	$ 21.60		21.60		$ 40.01
Exercisable, end of period, weighted average exercise price	$ 21.60		21.60
Additional disclosures
Weighted average fair value at grant date of options granted			$ 9.75
Total intrinsic value of options outstanding	$ 127,000		$ 127,000
Total intrinsic value of options exercisable	$ 25,300		$ 25,300