Loans - Credit Quality (Details) - USD ($)	12 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Unpaid principal balance by credit quality indicator
Unpaid principal balance	$ 239,452,928	$ 200,694,437
Performing Financing Receivable Maximum Days Past Due	31 days
Nonperforming Financing Receivable Minimum Days Past Due	31 days
Commercial and Agricultural
Unpaid principal balance by credit quality indicator
Unpaid principal balance	$ 180,969,878	144,173,099
Financing Receivable Risk Rating Minimum Review Period	12 months
Maximum aggregate exposure not requiring a loan review within 12 months of most recent credit review	$ 250,000
Commercial
Unpaid principal balance by credit quality indicator
Unpaid principal balance	106,948,983	83,054,605
Commercial | Operating
Unpaid principal balance by credit quality indicator
Unpaid principal balance	20,139,045	15,355,676
Commercial | Real Estate
Unpaid principal balance by credit quality indicator
Unpaid principal balance	86,809,938	67,698,929
Agricultural
Unpaid principal balance by credit quality indicator
Unpaid principal balance	57,845,197	47,908,101
Agricultural | Operating
Unpaid principal balance by credit quality indicator
Unpaid principal balance	26,739,407	22,942,560
Agricultural | Real Estate
Unpaid principal balance by credit quality indicator
Unpaid principal balance	31,105,790	24,965,541
Residential Real Estate and Other Combined
Unpaid principal balance by credit quality indicator
Unpaid principal balance	58,483,050	56,521,338
Residential
Unpaid principal balance by credit quality indicator
Unpaid principal balance	54,808,376	52,954,421
Residential | 1 - 4 family
Unpaid principal balance by credit quality indicator
Unpaid principal balance	43,060,013	40,309,797
Residential | Consumer - Home equity and lines of credit
Unpaid principal balance by credit quality indicator
Unpaid principal balance	11,748,363	12,644,624
Other
Unpaid principal balance by credit quality indicator
Unpaid principal balance	19,850,372	16,777,310
Other | Construction and land
Unpaid principal balance by credit quality indicator
Unpaid principal balance	16,175,698	13,210,393
Other | Consumer - Personal
Unpaid principal balance by credit quality indicator
Unpaid principal balance	3,674,674	3,566,917
Highest Quality (rating 1) | Commercial and Agricultural
Unpaid principal balance by credit quality indicator
Unpaid principal balance	650,083	832,824
Highest Quality (rating 1) | Agricultural | Operating
Unpaid principal balance by credit quality indicator
Unpaid principal balance	324,038	484,813
Highest Quality (rating 1) | Agricultural | Real Estate
Unpaid principal balance by credit quality indicator
Unpaid principal balance	326,045	348,011
Good Quality (rating 2) | Commercial and Agricultural
Unpaid principal balance by credit quality indicator
Unpaid principal balance	18,412,202	18,808,405
Good Quality (rating 2) | Commercial | Operating
Unpaid principal balance by credit quality indicator
Unpaid principal balance	177,795	213,824
Good Quality (rating 2) | Commercial | Real Estate
Unpaid principal balance by credit quality indicator
Unpaid principal balance	6,638,998	4,923,002
Good Quality (rating 2) | Agricultural | Operating
Unpaid principal balance by credit quality indicator
Unpaid principal balance	5,185,147	5,510,208
Good Quality (rating 2) | Agricultural | Real Estate
Unpaid principal balance by credit quality indicator
Unpaid principal balance	3,541,630	6,173,479
Good Quality (rating 2) | Other | Construction and land
Unpaid principal balance by credit quality indicator
Unpaid principal balance	2,868,632	1,987,892
Acceptable Quality (rating 3) | Commercial and Agricultural
Unpaid principal balance by credit quality indicator
Unpaid principal balance	84,763,249	63,736,162
Acceptable Quality (rating 3) | Commercial | Operating
Unpaid principal balance by credit quality indicator
Unpaid principal balance	8,470,283	7,732,341
Acceptable Quality (rating 3) | Commercial | Real Estate
Unpaid principal balance by credit quality indicator
Unpaid principal balance	44,240,531	33,606,696
Acceptable Quality (rating 3) | Agricultural | Operating
Unpaid principal balance by credit quality indicator
Unpaid principal balance	9,271,425	5,992,063
Acceptable Quality (rating 3) | Agricultural | Real Estate
Unpaid principal balance by credit quality indicator
Unpaid principal balance	12,354,765	9,729,301
Acceptable Quality (rating 3) | Other | Construction and land
Unpaid principal balance by credit quality indicator
Unpaid principal balance	10,426,245	6,675,761
Fair Quality (rating 4) | Commercial and Agricultural
Unpaid principal balance by credit quality indicator
Unpaid principal balance	70,403,654	57,861,158
Fair Quality (rating 4) | Commercial | Operating
Unpaid principal balance by credit quality indicator
Unpaid principal balance	11,313,276	7,294,630
Fair Quality (rating 4) | Commercial | Real Estate
Unpaid principal balance by credit quality indicator
Unpaid principal balance	31,603,455	28,578,771
Fair Quality (rating 4) | Agricultural | Operating
Unpaid principal balance by credit quality indicator
Unpaid principal balance	11,489,750	9,604,176
Fair Quality (rating 4) | Agricultural | Real Estate
Unpaid principal balance by credit quality indicator
Unpaid principal balance	13,116,352	7,836,841
Fair Quality (rating 4) | Other | Construction and land
Unpaid principal balance by credit quality indicator
Unpaid principal balance	2,880,821	4,546,740
Special Mention | Commercial and Agricultural
Unpaid principal balance by credit quality indicator
Unpaid principal balance	2,351,251	829,738
Special Mention | Commercial | Real Estate
Unpaid principal balance by credit quality indicator
Unpaid principal balance	1,948,017
Special Mention | Agricultural | Operating
Unpaid principal balance by credit quality indicator
Unpaid principal balance	403,234	829,738
Substandard | Commercial and Agricultural
Unpaid principal balance by credit quality indicator
Unpaid principal balance	4,389,439	2,104,812
Substandard | Commercial | Operating
Unpaid principal balance by credit quality indicator
Unpaid principal balance	177,691	114,881
Substandard | Commercial | Real Estate
Unpaid principal balance by credit quality indicator
Unpaid principal balance	2,378,937	590,460
Substandard | Agricultural | Operating
Unpaid principal balance by credit quality indicator
Unpaid principal balance	65,813	521,562
Substandard | Agricultural | Real Estate
Unpaid principal balance by credit quality indicator
Unpaid principal balance	1,766,998	877,909
Performing | Residential Real Estate and Other Combined
Unpaid principal balance by credit quality indicator
Unpaid principal balance	57,596,501	54,006,030
Performing | Residential | 1 - 4 family
Unpaid principal balance by credit quality indicator
Unpaid principal balance	42,220,268	37,832,838
Performing | Residential | Consumer - Home equity and lines of credit
Unpaid principal balance by credit quality indicator
Unpaid principal balance	11,725,714	12,614,817
Performing | Other | Consumer - Personal
Unpaid principal balance by credit quality indicator
Unpaid principal balance	3,650,519	3,558,375
Nonperforming | Residential Real Estate and Other Combined
Unpaid principal balance by credit quality indicator
Unpaid principal balance	886,549	2,515,308
Nonperforming | Residential | 1 - 4 family
Unpaid principal balance by credit quality indicator
Unpaid principal balance	839,745	2,476,959
Nonperforming | Residential | Consumer - Home equity and lines of credit
Unpaid principal balance by credit quality indicator
Unpaid principal balance	22,649	29,807
Nonperforming | Other | Consumer - Personal
Unpaid principal balance by credit quality indicator
Unpaid principal balance	$ 24,155	$ 8,542