Note 11 - Derivative - Interest Rate Swap Agreements (Details Textual) - USD ($)	3 Months Ended	12 Months Ended
Sep. 30, 2015	Mar. 31, 2018	Mar. 31, 2017
Derivative, Notional Amount		$ 11,550,000
Finite-Lived Intangible Assets, Amortization Expense, Next Twelve Months		126,070
Interest Rate Swap [Member]
Unrealized Gain (Loss) on Cash Flow Hedging Instruments		0	$ 0
Interest Rate Swap [Member] \| Cash Flow Hedging [Member]
Derivative Liability, Fair Value of Collateral		751,000	392,000
Derivative Instruments, Gain (Loss) Recognized in Income, Ineffective Portion and Amount Excluded from Effectiveness Testing, Net, Total		(1,075)
Finite-Lived Intangible Assets, Amortization Expense, Next Twelve Months		110,926	4,800
Interest Rate Swap [Member] \| Cash Flow Hedging [Member] \| Federal Home Loan Bank Advances [Member]
Derivative, Notional Amount		11,600,000
Derivative Instruments, Gain (Loss) Recognized in Income, Ineffective Portion and Amount Excluded from Effectiveness Testing, Net, Total		1,075
Interest Rate Swap [Member] \| Fair Value Hedging [Member]
Derivative, Notional Amount	$ 3,300,000	$ 3,100,000	$ 3,200,000
Derivative, Fixed Interest Rate	3.99%
Derivative, Term of Contract	10 years

Aggregate notional amount specified by the derivative(s). Expressed as an absolute value.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Article 12
-Section 13
-Sentence Column B

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- Definition

Fixed interest rate related to the interest rate derivative.

+ References

No definition available.

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- Definition

The portion of gains and losses (net) on derivative instruments designated and qualifying as hedging instruments representing (a) the amount of the hedge ineffectiveness and (b) the amount, if any, excluded from the assessment of hedge effectiveness.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4C
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5624171-113959

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 25
-Section 50
-Paragraph 1
-Subparagraph (a)(1),(2)
-URI http://asc.fasb.org/extlink&oid=109977999&loc=d3e76258-113986

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- Definition

Fair value of securities pledged as collateral against derivative liabilities.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 20
-Section 55
-Paragraph 12
-URI http://asc.fasb.org/extlink&oid=99393222&loc=SL20226013-175313

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- Definition

Period the derivative contract is outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

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- Definition

Amount of amortization expense for assets, excluding financial assets and goodwill, lacking physical substance with a finite life expected to be recognized during the next fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 30
-Section 50
-Paragraph 2
-Subparagraph (a)(3)
-URI http://asc.fasb.org/extlink&oid=66006027&loc=d3e16323-109275

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- Definition

Amount of unrealized gain (loss) related to derivatives designated as cash flow hedging instruments, recorded in results of operations to the extent that the cash flow hedge is determined to be ineffective.

+ References

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