Fair Value Measurements - Financial Instruments (Details) - USD ($)	Jun. 30, 2017	Jun. 30, 2016
Financial assets:
Cash and due from financial institutions	$ 4,881,007	$ 2,567,296
Securities available-for-sale	1,410,955	664,755
Securities held-to-maturity	745,873	801,114
Federal Home Loan Bank stock	453,400	229,900
Loans, net	236,545,125	198,309,920
Accrued interest receivable	1,297,908	1,147,467
Financial liabilities:
Noninterest-bearing deposits	29,546,051	24,296,166
Interest-bearing deposits	179,512,265	162,666,186
Federal funds purchased	399,000
Federal Home Loan Bank borrowings	6,745,400
Accrued interest payable and other liabilities	820,229	1,198,850
Carrying Amount | Level 1
Financial assets:
Cash and due from financial institutions	4,881,007	14,947,296
Federal Home Loan Bank stock	453,400	229,900
Accrued interest receivable	1,297,908	1,147,467
Financial liabilities:
Accrued interest payable and other liabilities	820,229	1,198,850
Carrying Amount | Level 2
Financial assets:
Securities available-for-sale	1,410,955	664,755
Securities held-to-maturity	735,978	781,740
Loans, net	236,545,125	198,309,920
Mortgage servicing rights	852,715	701,293
Financial liabilities:
Noninterest-bearing deposits	29,546,051	24,296,166
Interest-bearing deposits	179,512,265	162,666,186
Federal Home Loan Bank borrowings	6,745,400
Estimated Fair Value | Level 1
Financial assets:
Cash and due from financial institutions	4,881,000	14,947,000
Federal Home Loan Bank stock	453,000	230,000
Accrued interest receivable	1,298,000	1,147,000
Financial liabilities:
Accrued interest payable and other liabilities	820,000	1,199,000
Estimated Fair Value | Level 2
Financial assets:
Securities available-for-sale	1,411,000	665,000
Securities held-to-maturity	746,000	801,000
Loans, net	232,931,000	198,000,000
Mortgage servicing rights	1,089,000	841,000
Financial liabilities:
Noninterest-bearing deposits	29,546,000	24,296,000
Interest-bearing deposits	185,040,000	$ 170,276,000
Federal Home Loan Bank borrowings	$ 6,745,000