Note 8 - Operating Leases (Details Textual)	12 Months Ended
Mar. 31, 2022 USD ($)	Mar. 31, 2021 USD ($)	Mar. 31, 2020 USD ($)
Operating Leases, Expense, Contingent Rentals	$ 73,000	$ 50,000	$ 49,000
Operating Lease, Weighted Average Discount Rate, Percent	7.20%
Operating Lease, Weighted Average Remaining Lease Term (Year)	12 years 2 months 12 days	13 years 6 months
Operating Lease, Cost	$ 603,000	$ 591,000
Operating Lease, Expense	713,000	616,000	623,000
State and Local Jurisdiction [Member]
Real Estate Tax Expense	$ 30,000	$ 28,000	$ 28,000
Solar Lease for Buildings [Member]
Leases, Number of Lease Properties	2
Lessee, Operating Lease, Term of Contract (Year)	84 months
Operating Lease, Weighted Average Discount Rate, Percent	5.50%
Equipment [Member]
Lessee, Operating Lease, Term of Contract (Year)	48 months
HAWAII1 [Member]
Leases, Number of Lease Properties	2
HAWAII1 [Member] \| Commercial Lease Expiring in 2035 [Member]
Lessee, Operating Lease, Term of Contract (Year)	40 years
HAWAII1 [Member] \| Commercial Lease Expiring in 2037 [Member]
Lessee, Operating Lease, Term of Contract (Year)	19 years

Represents number of lease properties under lease agreement.

No definition available.

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- Definition

The increases or decreases in lease payments that result from changes occurring after the inception of the lease in the factors (other than the passage of time) on which lease payments are based, except that any escalation of minimum lease payments relating to increases in construction or acquisition cost of the leased property or for increases in some measure of cost or value during the construction or preconstruction period, are excluded from contingent rentals. Contingent rentals also may include amounts for which the triggering events have not yet occurred or the specified targets for which have not yet been achieved (such as sales based percentage rent), but which events are considered probable of occurring or which specified targets are considered probable of being achieved.

+ References

No definition available.

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- Definition

Term of lessee's operating lease, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 50
-Paragraph 3
-Subparagraph (a)(3)
-URI https://asc.fasb.org/extlink&oid=128292326&loc=SL77918673-209980

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- Definition

Amount of single lease cost, calculated by allocation of remaining cost of lease over remaining lease term. Includes, but is not limited to, single lease cost, after impairment of right-of-use asset, calculated by amortization of remaining right-of-use asset and accretion of lease liability.

+ References

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-Publisher FASB
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- Definition

Amount of operating lease expense. Excludes sublease income.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 45
-Paragraph 4
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-URI https://asc.fasb.org/extlink&oid=123391704&loc=SL77918638-209977

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- Definition

Weighted average discount rate for operating lease calculated at point in time.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
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- Definition

Weighted average remaining lease term for operating lease, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
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- Definition

A tax based on the assessed value of real estate by the local government. The tax is usually based on the value of property (including the land).

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