Significant Accounting Policies - Inventories (Details) - USD ($) $ in Thousands	Sep. 30, 2025	Mar. 31, 2025
Inventory
Crude oil	$ 44,538	$ 23,962
Propane	14,137	11,847
Total	118,003	69,916
Butane inventory
Inventory
Energy Related Inventory, Natural Gas Liquids	52,856	22,674
Other natural gas liquids
Inventory
Energy Related Inventory, Natural Gas Liquids	$ 6,472	$ 11,433

Carrying amount as of the balance sheet date of liquid hydrocarbon components recovered from natural gas.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 210
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-Name Accounting Standards Codification
-Section S99
-Paragraph 1
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-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1

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- Definition

Carrying amount as of the balance sheet date of petroleum or crude oil.

+ References

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Carrying amount as of the balance sheet date of product derived from petroleum during the processing of oil or natural gas which is then used as a heat source or fuel.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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Amount after valuation and LIFO reserves of inventory expected to be sold, or consumed within one year or operating cycle, if longer.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 852
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 10
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481372/852-10-55-10

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 1
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483467/210-10-45-1

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 210
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