Note 19 - Fair Value Measurements - Reconciliation of Investments at Fair Value on Recurring Basis (Details) - USD ($)	12 Months Ended
Mar. 31, 2018	Mar. 31, 2017
Balance, beginning of year	$ 1,930,786	$ 1,898,640
Balance, end of year	1,954,092	1,930,786
Corporate Bond Securities [Member]
Transfers in	1,954,076
Transfers out		1,898,640
Collateralized Mortgage Backed Securities [Member]
Transfers in	16	2,473
Transfers out	2,473
Municipal Bonds [Member]
Transfers in		1,928,313
Transfers out	$ 1,928,313

Amount of transfer of financial instrument classified as an asset into level 3 of the fair value hierarchy.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(3)
-URI http://asc.fasb.org/extlink&oid=99377789&loc=d3e19207-110258

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- Definition

Amount of transfers of financial instrument classified as an asset out of level 3 of the fair value hierarchy.

+ References

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- Definition

Fair value of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=99377789&loc=d3e19207-110258

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