Loans and Allowance for Credit Losses - Allowance for off-balance credit exposure (Details) - USD ($)	3 Months Ended		6 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2024	Dec. 31, 2023
Allowance for off-balance sheet credit exposure:
Balance, beginning of period	$ 3,401,000	$ 5,618,000	$ 3,263,000	$ 6,288,000
Provision (benefit) charged to expense	431,000	(1,022,000)	569,000	(1,692,000)
Balance, end of period	3,832,000	4,596,000	3,832,000	4,596,000
Commercial and industrial
Allowance for off-balance sheet credit exposure:
Balance, beginning of period	802,000	767,000	782,000	730,000
Provision (benefit) charged to expense	230,000	(39,000)	250,000	(2,000)
Balance, end of period	1,032,000	728,000	1,032,000	728,000
Agriculture production
Allowance for off-balance sheet credit exposure:
Balance, beginning of period	34,000	23,000	37,000	107,000
Provision (benefit) charged to expense	93,000	134,000	90,000	50,000
Balance, end of period	127,000	157,000	127,000	157,000
Consumer
Allowance for off-balance sheet credit exposure:
Balance, beginning of period	12,000	17,000	12,000	16,000
Provision (benefit) charged to expense	(6,000)	(3,000)	(6,000)	(2,000)
Balance, end of period	6,000	14,000	6,000	14,000
All other loans
Allowance for off-balance sheet credit exposure:
Balance, beginning of period		7,000		10,000
Provision (benefit) charged to expense		(7,000)		(10,000)
Secured by real estate | 1-4 residential real estate
Allowance for off-balance sheet credit exposure:
Balance, beginning of period	170,000	131,000	140,000	126,000
Provision (benefit) charged to expense	59,000	5,000	89,000	10,000
Balance, end of period	229,000	136,000	229,000	136,000
Secured by real estate | Commercial Real Estate | Non-owner occupied
Allowance for off-balance sheet credit exposure:
Balance, beginning of period	175,000	154,000	153,000	154,000
Provision (benefit) charged to expense	10,000	(3,000)	32,000	(3,000)
Balance, end of period	185,000	151,000	185,000	151,000
Secured by real estate | Commercial Real Estate | Owner occupied
Allowance for off-balance sheet credit exposure:
Balance, beginning of period	122,000	180,000	136,000	182,000
Provision (benefit) charged to expense	47,000	(5,000)	33,000	(7,000)
Balance, end of period	169,000	175,000	169,000	175,000
Secured by real estate | Multi-family real estate
Allowance for off-balance sheet credit exposure:
Balance, beginning of period	34,000	15,000	31,000	16,000
Provision (benefit) charged to expense	31,000	(6,000)	34,000	(7,000)
Balance, end of period	65,000	9,000	65,000	9,000
Secured by real estate | Construction and land development
Allowance for off-balance sheet credit exposure:
Balance, beginning of period	2,000,000	4,285,000	1,912,000	4,897,000
Provision (benefit) charged to expense	(35,000)	(1,106,000)	53,000	(1,718,000)
Balance, end of period	1,965,000	3,179,000	1,965,000	3,179,000
Secured by real estate | Agriculture real estate
Allowance for off-balance sheet credit exposure:
Balance, beginning of period	52,000	39,000	60,000	50,000
Provision (benefit) charged to expense	2,000	8,000	(6,000)	(3,000)
Balance, end of period	$ 54,000	$ 47,000	$ 54,000	$ 47,000