Note 6 - Derivative Financial Instruments - Gain (Loss) Recognized in Earnings for Derivative Instruments (Details) - USD ($)	12 Months Ended
Mar. 31, 2022	Mar. 31, 2021
Hot-rolled coil steel contracts	$ (1,216,500)	$ (0)
Nonoperating Income (Expense) [Member]
Hot-rolled coil steel contracts	(11,636,120)
Nonoperating Income (Expense) [Member] \| Hot-rolled Coil Steel Contracts [Member]
Hot-rolled coil steel contracts	$ (11,636,120)	$ (515,160)

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

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4CC
-URI https://asc.fasb.org/extlink&oid=125515794&loc=SL109998890-113959

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4C
-Subparagraph (e)
-URI https://asc.fasb.org/extlink&oid=125515794&loc=SL5624171-113959

Name:	us-gaap_DerivativeInstrumentsNotDesignatedAsHedgingInstrumentsGainLossNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration