Note 10 - Goodwill and Other Intangible Assets (Details Textual) - USD ($)		3 Months Ended	12 Months Ended
	May 13, 2016	Jun. 30, 2016	Mar. 31, 2018	Mar. 31, 2017
Business Acquisition, Goodwill, Expected Tax Deductible Amount			$ 2,700,000
Goodwill, Impairment Loss			$ 0
Fairmount Bancorp, Inc. [Member]
Operating Loss Carryforwards, Total		$ 533,000
Real Estate Loans [Member] | One-to four-family [Member]
Financing Receivables, Impaired, Troubled Debt Restructuring, Write-down		$ 451,000
Core Deposits [Member]
Finite-Lived Intangible Asset, Useful Life	8 years		8 years