Note 7 - Derivative Financial Instruments - Gain (Loss) Recognized in Earnings for Derivative Instruments (Details) - USD ($) $ in Thousands	12 Months Ended
Mar. 31, 2023	Mar. 31, 2022
Hot-rolled coil steel contracts	$ (459)	$ (1,217)
Nonoperating Income (Expense) [Member] \| Hot-rolled Coil Steel Contracts [Member]
Hot-rolled coil steel contracts	$ 9,306	$ (11,636)

Amount of realized and unrealized gain (loss) of derivative instruments not designated or qualifying as hedging instruments.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4C
-Subparagraph (e)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480434/815-10-50-4C

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Name Accounting Standards Codification
-Section 50
-Paragraph 4CC
-SubTopic 10
-Topic 815
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480434/815-10-50-4CC

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