Income Taxes - Schedule of Components of Deferred Income Taxes (Detail) - USD ($) $ in Thousands	Mar. 31, 2025	Mar. 31, 2024
Income Tax Disclosure [Abstract]
Excess Tax Depreciation and Amortization	$ (256,999)	$ (260,577)
Depletable Assets	(4,455)	(4,294)
Investment in Joint Venture Basis Differences	(6,436)	(7,710)
Right-of-Use Assets	(7,996)	(4,774)
Inventory	(1,276)	0
Other	0	(2,956)
Total Deferred Tax Liabilities	(277,162)	(280,311)
Change in Accruals	12,866	13,313
Bad Debts	1,551	1,621
Long-term Incentive Compensation Plan	4,609	3,622
Credits and Other Carryforwards	9,905	11,466
Lease Liability	9,303	6,598
Inventory	0	307
Pension	984	1,087
Other	1,002	0
Subtotal	40,220	38,014
Valuation Allowance	(3,000)	(2,500)
Total Deferred Tax Assets	$ 37,220	$ 35,514

Deferred tax assets, lease liability.

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Deferred tax liabilities, depletable assets.

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Deferred tax liabilities, right of use asset.

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Amount of deferred tax liability attributable to taxable temporary differences.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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-Name Accounting Standards Codification
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Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences and carryforwards.

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Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences from inventory.

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Amount after allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences and carryforwards.

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Amount, before allocation of valuation allowance, of deferred tax asset attributable to deductible tax credit carryforwards, classified as other.

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Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences from compensation and benefits costs.

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Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences from pension benefits.

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Amount, before allocation of valuation allowance, of deferred tax asset attributable to deductible temporary differences from provisions, reserves, allowances, and accruals, classified as other.

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Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences from accrued liabilities.

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Amount, before allocation of valuation allowance, of deferred tax asset attributable to deductible temporary difference from allowance for credit loss on accounts receivable.

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Amount of deferred tax assets for which it is more likely than not that a tax benefit will not be realized.

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Amount of deferred tax consequences attributable to taxable temporary differences derived from inventory.

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Amount of deferred tax liability attributable to taxable temporary differences from investments (excludes investments in subsidiaries and equity method investments).

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Amount of deferred tax liability attributable to taxable temporary differences classified as other.

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Amount of deferred tax liability attributable to taxable temporary differences from property, plant, and equipment.

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