Loans - Allowance for loan losses (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2023	Dec. 31, 2022	Jun. 30, 2023
Allowance for credit losses:
Beginning balance	$ 3,587	$ 3,333	$ 3,313
Beginning balance				$ 3,409
Charge-offs	(13)		(13)
Charge-offs				(79)
Recoveries	2		28
Recoveries		1		4
Provision (recovery)	25		30
Ending balance	3,601		3,601
Ending Balance		3,334		3,334
Allowance ending balance:
Collectively evaluated for impairment	3,601		3,601
Collectively evaluated for impairment					$ 3,313
Allowance for loan losses	3,601		3,601
Allowance for loan losses		3,334		3,334	3,313
Loans receivable ,Individually evaluated for impairment	3,017		3,017		3,252
Loans receivable, Collectively evaluated for impairment	467,798		467,798		380,012
Total Loans	470,815		470,815
Total Loans					480,856
Cumulative Effect, Period of Adoption, Adjustment
Allowance for credit losses:
Ending balance	243		243
Allowance ending balance:
Allowance for loan losses	243		243
Acquired credit impaired
Allowance ending balance:
Loans receivable, Collectively evaluated for impairment					72
Acquired non-credit impaired
Allowance ending balance:
Loans receivable, Collectively evaluated for impairment					97,520
Residential real estate | 1-4 Family
Allowance for credit losses:
Beginning balance	407	493	486
Beginning balance			419	506
Charge-offs				(79)
Provision (recovery)	(4)		(16)
Provision (recovery)		21		87
Ending balance	403		403
Ending Balance		514		514
Allowance ending balance:
Collectively evaluated for impairment	403		403
Collectively evaluated for impairment					486
Allowance for loan losses	403		403		419
Allowance for loan losses		514		514	486
Loans receivable ,Individually evaluated for impairment	1,480		1,480		1,209
Loans receivable, Collectively evaluated for impairment	128,190		128,190		78,237
Total Loans	129,670		129,670
Total Loans					135,046
Residential real estate | 1-4 Family | Cumulative Effect, Period of Adoption, Adjustment
Allowance for credit losses:
Ending balance	(67)		(67)
Allowance ending balance:
Allowance for loan losses	(67)		(67)
Residential real estate | 1-4 Family | Acquired credit impaired
Allowance ending balance:
Loans receivable, Collectively evaluated for impairment					72
Residential real estate | 1-4 Family | Acquired non-credit impaired
Allowance ending balance:
Loans receivable, Collectively evaluated for impairment					55,528
Residential real estate | Home equity and HELOCs
Allowance for credit losses:
Beginning balance	131	116	113
Beginning balance			132	113
Provision (recovery)	84		83
Provision (recovery)		(7)		(4)
Ending balance	215		215
Ending Balance		109		109
Allowance ending balance:
Collectively evaluated for impairment	215		215
Collectively evaluated for impairment					113
Allowance for loan losses	215		215		132
Allowance for loan losses		109		109	113
Loans receivable ,Individually evaluated for impairment	16		16		182
Loans receivable, Collectively evaluated for impairment	31,166		31,166		19,689
Total Loans	31,182		31,182
Total Loans					32,684
Residential real estate | Home equity and HELOCs | Cumulative Effect, Period of Adoption, Adjustment
Allowance for credit losses:
Ending balance	19		19
Allowance ending balance:
Allowance for loan losses	19		19
Residential real estate | Home equity and HELOCs | Acquired non-credit impaired
Allowance ending balance:
Loans receivable, Collectively evaluated for impairment					12,813
Residential real estate | Construction Residential
Allowance for credit losses:
Beginning balance	39	301	214
Beginning balance			40	386
Provision (recovery)	5		4
Provision (recovery)		(29)		(114)
Ending balance	44		44
Ending Balance		272		272
Allowance ending balance:
Collectively evaluated for impairment	44		44
Collectively evaluated for impairment					214
Allowance for loan losses	44		44		40
Allowance for loan losses		272		272	214
Loans receivable, Collectively evaluated for impairment	9,899		9,899		9,113
Total Loans	9,899		9,899
Total Loans					9,113
Residential real estate | Construction Residential | Cumulative Effect, Period of Adoption, Adjustment
Allowance for credit losses:
Ending balance	(174)		(174)
Allowance ending balance:
Allowance for loan losses	(174)		(174)
Commercial real estate
Allowance ending balance:
Total Loans	52,700		52,700
Commercial real estate | 1-4 Family
Allowance for credit losses:
Ending balance	317		317
Allowance ending balance:
Collectively evaluated for impairment	317		317
Allowance for loan losses	317		317
Loans receivable ,Individually evaluated for impairment	102		102
Loans receivable, Collectively evaluated for impairment	94,234		94,234
Total Loans	94,336		94,336
Commercial real estate | 1 - 4 family investor
Allowance for credit losses:
Beginning balance	325	495	569
Beginning balance			328	527
Provision (recovery)	(8)		(11)
Provision (recovery)		13		(19)
Ending balance	317		317
Ending Balance		508		508
Allowance ending balance:
Collectively evaluated for impairment					569
Allowance for loan losses	317		317		328
Allowance for loan losses		508		508	569
Loans receivable ,Individually evaluated for impairment					832
Loans receivable, Collectively evaluated for impairment					84,891
Total Loans	94,336		94,336
Total Loans					98,160
Commercial real estate | 1 - 4 family investor | Cumulative Effect, Period of Adoption, Adjustment
Allowance for credit losses:
Ending balance	(241)		(241)
Allowance ending balance:
Allowance for loan losses	(241)		(241)
Commercial real estate | 1 - 4 family investor | Acquired non-credit impaired
Allowance ending balance:
Loans receivable, Collectively evaluated for impairment					12,437
Commercial real estate | Multi-family (five or more)
Allowance for credit losses:
Beginning balance	53	112	89
Beginning balance			59	110
Provision (recovery)	(1)		(7)
Provision (recovery)		(20)		(18)
Ending balance	52		52
Ending Balance		92		92
Allowance ending balance:
Collectively evaluated for impairment	52		52
Collectively evaluated for impairment					89
Allowance for loan losses	52		52		59
Allowance for loan losses		92		92	89
Loans receivable ,Individually evaluated for impairment	223		223		251
Loans receivable, Collectively evaluated for impairment	14,883		14,883		14,781
Total Loans	15,106		15,106
Total Loans					15,281
Commercial real estate | Multi-family (five or more) | Cumulative Effect, Period of Adoption, Adjustment
Allowance for credit losses:
Ending balance	(30)		(30)
Allowance ending balance:
Allowance for loan losses	(30)		(30)
Commercial real estate | Multi-family (five or more) | Acquired non-credit impaired
Allowance ending balance:
Loans receivable, Collectively evaluated for impairment					249
Commercial real estate | Commercial non-residential
Allowance for credit losses:
Beginning balance	1,767	1,431	1,420
Beginning balance			1,799	1,451
Provision (recovery)	(13)		(45)
Provision (recovery)		(22)		(42)
Ending balance	1,754		1,754
Ending Balance		1,409		1,409
Allowance ending balance:
Collectively evaluated for impairment	1,754		1,754
Collectively evaluated for impairment					1,420
Allowance for loan losses	1,754		1,754		1,799
Allowance for loan losses		1,409		1,409	1,420
Loans receivable ,Individually evaluated for impairment	1,085		1,085		778
Loans receivable, Collectively evaluated for impairment	152,801		152,801		142,098
Total Loans	153,886		153,886
Total Loans					157,555
Commercial real estate | Commercial non-residential | Cumulative Effect, Period of Adoption, Adjustment
Allowance for credit losses:
Ending balance	379		379
Allowance ending balance:
Allowance for loan losses	379		379
Commercial real estate | Commercial non-residential | Acquired non-credit impaired
Allowance ending balance:
Loans receivable, Collectively evaluated for impairment					14,679
Commercial real estate | Construction and land
Allowance for credit losses:
Beginning balance	233	224	281
Beginning balance			188	166
Provision (recovery)	7		52
Provision (recovery)		25		83
Ending balance	240		240
Ending Balance		249		249
Allowance ending balance:
Collectively evaluated for impairment	240		240
Collectively evaluated for impairment					281
Allowance for loan losses	240		240		188
Allowance for loan losses		249		249	281
Loans receivable, Collectively evaluated for impairment	19,953		19,953		15,584
Total Loans	19,953		19,953
Total Loans					15,584
Commercial real estate | Construction and land | Cumulative Effect, Period of Adoption, Adjustment
Allowance for credit losses:
Ending balance	(93)		(93)
Allowance ending balance:
Allowance for loan losses	(93)		(93)
Commercial
Allowance for credit losses:
Beginning balance	340	111	82
Beginning balance			336	100
Provision (recovery)	(18)		(14)
Provision (recovery)		12		23
Ending balance	322		322
Ending Balance		123		123
Allowance ending balance:
Collectively evaluated for impairment	322		322
Collectively evaluated for impairment					82
Allowance for loan losses	322		322		336
Allowance for loan losses		123		123	82
Loans receivable, Collectively evaluated for impairment	14,786		14,786		14,976
Total Loans	14,786		14,786
Total Loans					15,433
Commercial | Cumulative Effect, Period of Adoption, Adjustment
Allowance for credit losses:
Ending balance	254		254
Allowance ending balance:
Allowance for loan losses	254		254
Commercial | Acquired non-credit impaired
Allowance ending balance:
Loans receivable, Collectively evaluated for impairment					457
Consumer
Allowance for credit losses:
Beginning balance	292	50	59
Beginning balance			255	50
Charge-offs	(13)		(13)
Recoveries	2		28
Recoveries		1		4
Provision (recovery)	(27)		(16)
Provision (recovery)		7		4
Ending balance	254		254
Ending Balance		58		58
Allowance ending balance:
Collectively evaluated for impairment	254		254
Collectively evaluated for impairment					59
Allowance for loan losses	254		254		255
Allowance for loan losses		$ 58		$ 58	59
Loans receivable ,Individually evaluated for impairment	111		111
Loans receivable, Collectively evaluated for impairment	1,886		1,886		643
Total Loans	1,997		1,997
Total Loans					2,000
Consumer | Cumulative Effect, Period of Adoption, Adjustment
Allowance for credit losses:
Ending balance	196		196
Allowance ending balance:
Allowance for loan losses	$ 196		$ 196
Consumer | Acquired non-credit impaired
Allowance ending balance:
Loans receivable, Collectively evaluated for impairment					$ 1,357