Available for Sale Securities - Unrealized losses (Details) - Obligations of states and political subdivisions	Sep. 30, 2020 USD ($) security	Jun. 30, 2020 USD ($) security
Debt Securities, Available-for-sale [Line Items]
Continuous Unrealized Losses Existing for Less Than 12 Months, Fair Value	$ 0	$ 0
Continuous Unrealized Losses Existing for Less Than 12 Months, Unrealized Losses	0	0
Continuous Unrealized Losses Existing for 12 Months or Greater, Fair Value	697,342	693,687
Continuous Unrealized Losses Existing for 12 Months or Greater, Unrealized Losses	11,780	16,056
Total, Fair Value	697,342	693,687
Total, Unrealized Losses	$ 11,780	$ 16,056
Number of securities with unrealized loss position | security	2	6