Note 6 - Long-term Debt - Summary of Long-term Debt (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Mar. 31, 2019
Long-term debt	$ 217,581	$ 266,245
Less current portion	500	345
Long-term debt	217,081	265,900
Line of Credit [Member]
Long-term debt	106,924	155,278
Term Loan [Member]
Long-term debt	99,941	99,906
Tax-exempt Bond [Member]
Long-term debt	10,000	10,000
Secured Promissory Note 1 [Member]
Long-term debt		262
Economic Development Note [Member]
Long-term debt	500	583
Other [Member]
Long-term debt	$ 216	$ 216

Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (b)(3)
-URI http://asc.fasb.org/extlink&oid=120520924&loc=SL6031897-161870

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(16))
-URI http://asc.fasb.org/extlink&oid=120400017&loc=d3e572229-122910

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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-Section S99
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Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
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Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt, classified as current. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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