Note 6 - Derivative Financial Instruments - Gain (Loss) Recognized in Earnings for Derivative Instruments (Details) - USD ($) $ in Thousands	12 Months Ended
Mar. 31, 2025	Mar. 31, 2024
Hot-rolled coil steel contracts	$ 1,961	$ 64
Nonoperating Income (Expense) [Member] \| Hot-rolled Coil Steel Contracts [Member]
Hot-rolled coil steel contracts	$ 7,598	$ 1,848

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

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 815
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 182
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480401/815-10-55-182

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 815
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 4CC
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480434/815-10-50-4CC

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 220
-SubTopic 40
-Name Accounting Standards Codification
-Section 50
-Paragraph 21
-Subparagraph (i)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147476148/220-40-50-21

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