Note 6 - Goodwill and Other Intangible Assets - Activity in Goodwill and Intangible Assets (Details) - USD ($)	6 Months Ended		12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Mar. 31, 2018
Goodwill, balance	$ 8,563,530	$ 8,563,530	$ 8,563,530
Goodwill, Amortization			0
Goodwill, balance	8,563,530	8,563,530	8,563,530
Core deposit intangible, Amortization	(63,032)	(63,032)
Core deposit intangible, balance	550,201
Core Deposits [Member]
Core deposit intangible, balance	613,234	739,298	739,298
Core deposit intangible, Amortization	(63,033)	(63,032)
Core deposit intangible, balance	$ 550,201	$ 676,266	$ 613,234