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Note 13 - Other Operating Income and Expense (Details Textual) - Other Operating Income (Expense) [Member] - USD ($) $ in Millions | 12 Months Ended
--- | ---
Mar. 31, 2020 | Mar. 31, 2019
Gain (Loss) on Disposition of Property Plant Equipment, Total | $ 1.2 |
Gain (Loss) On Partial Sale of Plant |  | $ 0.8
Interest Rate Swap [Member] |  |
Gain (Loss) on Sale of Derivatives |  | 0.3
Midwest Plant [Member] |  |
Gain (Loss) On Sale of Plant | 3.3 | 4.1
Northwest Plant [Member] |  |
Gain (Loss) On Sale of Plant | $ 8.2 |
Northeast Plant [Member] |  |
Gain (Loss) On Sale of Plant |  | 2.0
Eastern Plant [Member] |  |
Gain (Loss) On Sale of Plant |  | $ (0.6)

X
- Definition Amount of gain (loss) on partial sale of plant. + References No definition available. + Details
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- Definition Amount of gain (loss) on sale of plant. + References No definition available. + Details
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X
- Definition The difference between the book value and the sale price of options, swaps, futures, forward contracts, and other derivative instruments. This element refers to the gain (loss) included in earnings. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3602-108585 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 220 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-04.13(h)) -URI http://asc.fasb.org/extlink&oid=120399700&loc=SL114874048-224260 + Details
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- Definition Amount of gain (loss) on sale or disposal of property, plant and equipment assets, including oil and gas property and timber property. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3602-108585 + Details
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- Details
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- Details
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- Details
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- Details
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- Details
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