Loans and Allowance for Credit Losses - Summary of Loans Receivable and Related Reclassifications (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Sep. 30, 2023	Mar. 31, 2023	Dec. 31, 2022	Sep. 30, 2022	Mar. 31, 2022
Financing Receivable, Past Due [Line Items]
Total Loans	$ 376,048		$ 353,687
Allowance for credit losses	(5,867)		(5,412)	$ (5,377)	$ (5,283)	$ (4,928)
Net deferred origination costs & fees	24
Loans-net	370,205		348,337
Real Estate
Financing Receivable, Past Due [Line Items]
Allowance for credit losses	(5,867)	$ (5,657)	(5,412)
Real Estate | Construction
Financing Receivable, Past Due [Line Items]
Total Loans	9,972
Allowance for credit losses	(197)	(398)	(334)
Real Estate | Commercial
Financing Receivable, Past Due [Line Items]
Total Loans	123,754		102,446
Allowance for credit losses	(2,305)	(1,277)	(2,048)	(2,047)	(1,962)	(1,845)
Real Estate | Residential
Financing Receivable, Past Due [Line Items]
Total Loans	151,215
Allowance for credit losses	(1,819)	(1,832)	(1,286)
Construction and Land Development | Non-1-4 Family
Financing Receivable, Past Due [Line Items]
Total Loans			23,644
Allowance for credit losses			(402)	(377)	(427)	(357)
Residential | 1-4 Family
Financing Receivable, Past Due [Line Items]
Total Loans			119,610
Allowance for credit losses			(686)	(611)	(600)	(636)
Residential | Multi-Family
Financing Receivable, Past Due [Line Items]
Total Loans			34,296
Allowance for credit losses			(670)	(670)	(620)	(481)
Commercial | Non-Real Estate
Financing Receivable, Past Due [Line Items]
Total Loans	34,068		30,101
Allowance for credit losses	(759)	(1,298)	(915)	(963)	(965)	(930)
Agriculture
Financing Receivable, Past Due [Line Items]
Total Loans	18,353
Allowance for credit losses	(211)	(240)	(484)
Agriculture | Real Estate
Financing Receivable, Past Due [Line Items]
Total Loans			9,245
Allowance for credit losses			(203)
Agriculture | Non-Real Estate
Financing Receivable, Past Due [Line Items]
Total Loans			8,921
Allowance for credit losses			(281)	(281)	(281)	(281)
Consumer
Financing Receivable, Past Due [Line Items]
Allowance for credit losses	(360)	(334)	(157)
Consumer | Auto
Financing Receivable, Past Due [Line Items]
Total Loans			5,622
Allowance for credit losses			(44)	(44)	(44)	(64)
Consumer | Other
Financing Receivable, Past Due [Line Items]
Total Loans			14,334
Allowance for credit losses			(113)	(131)	(131)	(71)
Other Consumer
Financing Receivable, Past Due [Line Items]
Total Loans	22,508
Land Development and SIDs
Financing Receivable, Past Due [Line Items]
Total Loans	16,178
Allowance for credit losses	$ (216)	$ (278)	(188)
Sanitary & Improvement Districts
Financing Receivable, Past Due [Line Items]
Total Loans			5,468
Allowance for credit losses			(50)	$ (50)	$ (50)	$ (50)
Pre Adoption
Financing Receivable, Past Due [Line Items]
Total Loans			353,687
Allowance for credit losses			(5,412)
Net deferred origination costs & fees			62
Loans-net			348,337
Pre Adoption | Real Estate | Commercial
Financing Receivable, Past Due [Line Items]
Total Loans			102,446
Pre Adoption | Construction and Land Development | Non-1-4 Family
Financing Receivable, Past Due [Line Items]
Total Loans			23,644
Pre Adoption | Residential | 1-4 Family
Financing Receivable, Past Due [Line Items]
Total Loans			119,610
Pre Adoption | Residential | Multi-Family
Financing Receivable, Past Due [Line Items]
Total Loans			34,296
Pre Adoption | Commercial | Non-Real Estate
Financing Receivable, Past Due [Line Items]
Total Loans			30,101
Pre Adoption | Agriculture | Real Estate
Financing Receivable, Past Due [Line Items]
Total Loans			9,245
Pre Adoption | Agriculture | Non-Real Estate
Financing Receivable, Past Due [Line Items]
Total Loans			8,921
Pre Adoption | Consumer | Auto
Financing Receivable, Past Due [Line Items]
Total Loans			5,622
Pre Adoption | Consumer | Other
Financing Receivable, Past Due [Line Items]
Total Loans			14,334
Pre Adoption | Sanitary & Improvement Districts
Financing Receivable, Past Due [Line Items]
Total Loans			5,468
The Effect of Adoption
Financing Receivable, Past Due [Line Items]
Allowance for credit losses			(299)
Loans-net			(299)
The Effect of Adoption | Real Estate | Construction
Financing Receivable, Past Due [Line Items]
Total Loans			19,301
The Effect of Adoption | Real Estate | Residential
Financing Receivable, Past Due [Line Items]
Total Loans			148,486
The Effect of Adoption | Construction and Land Development | Non-1-4 Family
Financing Receivable, Past Due [Line Items]
Total Loans			(23,644)
The Effect of Adoption | Residential | 1-4 Family
Financing Receivable, Past Due [Line Items]
Total Loans			(119,610)
The Effect of Adoption | Residential | Multi-Family
Financing Receivable, Past Due [Line Items]
Total Loans			(34,296)
The Effect of Adoption | Agriculture
Financing Receivable, Past Due [Line Items]
Total Loans			18,166
The Effect of Adoption | Agriculture | Real Estate
Financing Receivable, Past Due [Line Items]
Total Loans			(9,245)
The Effect of Adoption | Agriculture | Non-Real Estate
Financing Receivable, Past Due [Line Items]
Total Loans			(8,921)
The Effect of Adoption | Consumer | Auto
Financing Receivable, Past Due [Line Items]
Total Loans			(5,622)
The Effect of Adoption | Consumer | Other
Financing Receivable, Past Due [Line Items]
Total Loans			(14,334)
The Effect of Adoption | Other Consumer
Financing Receivable, Past Due [Line Items]
Total Loans			19,956
The Effect of Adoption | Land Development and SIDs
Financing Receivable, Past Due [Line Items]
Total Loans			15,231
The Effect of Adoption | Sanitary & Improvement Districts
Financing Receivable, Past Due [Line Items]
Total Loans			(5,468)
Post Adoption
Financing Receivable, Past Due [Line Items]
Total Loans			353,687
Allowance for credit losses			(5,711)
Net deferred origination costs & fees			62
Loans-net			348,038
Post Adoption | Real Estate | Construction
Financing Receivable, Past Due [Line Items]
Total Loans			19,301
Post Adoption | Real Estate | Commercial
Financing Receivable, Past Due [Line Items]
Total Loans			102,446
Post Adoption | Real Estate | Residential
Financing Receivable, Past Due [Line Items]
Total Loans			148,486
Post Adoption | Commercial | Non-Real Estate
Financing Receivable, Past Due [Line Items]
Total Loans			30,101
Post Adoption | Agriculture
Financing Receivable, Past Due [Line Items]
Total Loans			18,166
Post Adoption | Other Consumer
Financing Receivable, Past Due [Line Items]
Total Loans			19,956
Post Adoption | Land Development and SIDs
Financing Receivable, Past Due [Line Items]
Total Loans			$ 15,231