Amount of contingent liability relating to take or pay arrangements.

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The amount of gain that could be realized upon the resolution of a contingency.

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The number of raw coal storage silos.

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The number of raw coal storage silos that experienced partial structure failure.

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The percent of plant capacity restored after partial structural failure.

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Total costs accrued as of the balance sheet date for environmental loss contingencies.

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The carrying amount of a liability for an asset retirement obligation. An asset retirement obligation is a legal obligation associated with the disposal or retirement of a tangible long-lived asset that results from the acquisition, construction or development, or the normal operations of a long-lived asset, except for certain obligations of lessees.

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Amount awarded from other party in judgment or settlement of litigation.

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The minimum amount the entity agreed to spend under the long-term purchase commitment.

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Period covered by the long-term purchase commitment, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Amount of loss contingency liability.

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Amount of damages awarded to the plaintiff in the legal matter.

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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.

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No definition available.

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Minimum amount to be expended to satisfy the terms of arrangements in which the entity has agreed to expend funds to procure goods or services, excluding long-term purchase commitments or unconditional purchase obligations.

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Amount of expense related to royalty payments under a contractual arrangement such as payment for mineral and drilling rights and use of technology or intellectual property.

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Note 7 - Commitments and Contingencies (Details) $ in Thousands						3 Months Ended		6 Months Ended
	Jul. 20, 2023 USD ($)	Mar. 04, 2022 USD ($)	Jul. 16, 2021 USD ($)	Jul. 15, 2021 USD ($)	Nov. 05, 2018 item	Jun. 30, 2023 USD ($)	Jun. 30, 2022 USD ($)	Jun. 30, 2023 USD ($)	Jun. 30, 2022 USD ($)
COMMITMENTS AND CONTINGENCIES
Royalty Expense						$ 7,000	$ 7,000	$ 16,000	$ 17,200
Compensatory damages	$ 7,700	$ 1,800		$ 7,700
Award to cover inconvenience and aggravation	$ 25,000		$ 25,000
Accrued amount						0		0
Resolution of a contingency						0		0
Number of raw coal storage silos, failure \| item					1
Number of raw coal storage silos \| item					3
Percentage of structural failure					80.00%
Surety Bond
COMMITMENTS AND CONTINGENCIES
Asset Retirement Obligation						26,100		26,100
Take-or-pay Purchase Commitments
COMMITMENTS AND CONTINGENCIES
Amount of contingent liability						0		0
Commitment						22,200		22,200
Total commitment								$ 36,000
Commitment term								5 years
Environmental
COMMITMENTS AND CONTINGENCIES
Environmental liabilities						$ 0		$ 0