Note 1 - General Business (Details Textual) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended	9 Months Ended
Sep. 30, 2022	Sep. 30, 2022	Sep. 30, 2022	Sep. 30, 2021
Mine Reclamation and Closing Liability, Noncurrent	$ 100	$ 100	$ 100
Payments for Repurchase of Redeemable Preferred Stock		600	585	$ (0)
Cancellation of Redeemable Noncontrolling Interests		$ 3,415	$ 3,415
Hoosier Energy [Member]
Long-Term Contract for Purchase of Electric Power, Term (Year)	3 years 6 months

Amount of cancellation on redeemable noncontrolling interests.

No definition available.

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Namespace Prefix:	hnrg_
Data Type:	xbrli:monetaryItemType
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Period Type:	duration

- Definition

Represents the Length of the term for the contract to purchase electric power.

+ References

No definition available.

+ Details

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Namespace Prefix:	hnrg_
Data Type:	xbrli:durationItemType
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- Definition

Amount of a reclamation and mine closing liability that is associated with a legal obligation for the closure and reclamation of a mine including the removal of buildings, equipment, machinery and other physical remnants of mining, closure of tailings impoundments, leach pads and other mine features, and contouring, covering and revegetation of waste rock piles and other disturbed areas.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The cash outflow for reacquisition of callable preferred stock.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 15
-Subparagraph (a)
-URI https://asc.fasb.org/extlink&oid=126954810&loc=d3e3291-108585

+ Details

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Period Type:	duration

- Details

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