Note 3 - Miscellaneous Other Income - Miscellaneous Other Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2022	Mar. 31, 2021
Interest Income	$ 1,329	$ 858
Royalty Income - Non-Operated Coal	1,062	1,601
Property Easements and Option Income	714	98
Rental Income	460	215
Other	783	417
Miscellaneous Other Income	$ 4,348	$ 3,189

Represents information related to property easements and option income.

No definition available.

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Represents information related to royalty income no-operated coal.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
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Period Type:	duration

- Definition

Amount of interest income earned from interest bearing assets classified as other.

+ References

No definition available.

+ Details

Name:	us-gaap_InterestIncomeOther
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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The aggregate amount of income or expense from ancillary business-related activities (that is to say, excluding major activities considered part of the normal operations of the business).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.7)
-URI https://asc.fasb.org/extlink&oid=126953954&loc=SL114868664-224227

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of income related to nonoperating activities, classified as other.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03(7)(d))
-URI https://asc.fasb.org/extlink&oid=126953954&loc=SL114868664-224227

+ Details

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- Definition

Income earned by providing the use of assets to an outside party in exchange for a payment or series of payments that is nonoperating in nature.

+ References

+ Details

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Balance Type:	credit
Period Type:	duration