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

No definition available.

Name:	hnrg_LongtermContractForPurchaseOfElectricPowerTerm
Namespace Prefix:	hnrg_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents purchase of plant’s capacity, percentage.

+ References

No definition available.

+ Details

Name:	hnrg_PurchaseOfPlantsCapacityPercentage
Namespace Prefix:	hnrg_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents purchase of plant’s energy and capacity, percentage.

+ References

No definition available.

+ Details

Name:	hnrg_PurchaseOfPlantsEnergyAndCapacityPercentage
Namespace Prefix:	hnrg_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents purchase of Plant’s Energy output, percentage.

+ References

No definition available.

+ Details

Name:	hnrg_PurchaseOfPlantsEnergyOutputPercentage
Namespace Prefix:	hnrg_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of consideration transferred, consisting of acquisition-date fair value of assets transferred by the acquirer, liabilities incurred by the acquirer, and equity interest issued by the acquirer.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 30
-Paragraph 8
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-Topic 805
-SubTopic 30
-Section 30
-Paragraph 7
-URI https://asc.fasb.org/extlink&oid=126966197&loc=d3e6578-128477

+ Details

Name:	us-gaap_BusinessCombinationConsiderationTransferred1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of deferred revenue expected to be recognized as such within one year or the normal operating cycle, if longer, assumed at the acquisition date.

+ References

+ Details

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

- Definition

The amount of inventory recognized as of the acquisition date.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 20
-Section 50
-Paragraph 1
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-Topic 805
-SubTopic 10
-Section 55
-Paragraph 37
-URI https://asc.fasb.org/extlink&oid=123455525&loc=d3e2207-128464

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
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- Details

Name:	dei_LegalEntityAxis=hnrg_HoosierEnergyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_StatementScenarioAxis=srt_ScenarioForecastMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_BusinessAcquisitionAxis=hnrg_HoosierEnergyAcquisitionMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_SubsequentEventTypeAxis=us-gaap_SubsequentEventMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongTermPurchaseCommitmentByCategoryOfItemPurchasedAxis=us-gaap_InventoriesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Note 15 - Subsequent Events (Details Textual) - USD ($) $ in Millions		19 Months Ended	31 Months Ended
	Oct. 21, 2022	May 31, 2023	Dec. 31, 2025
Hoosier Energy [Member] \| Forecast [Member]
Purchase of Plant’s Energy and Capacity, Percentage		100.00%
Purchase of Plant’s Energy Output, Percentage			22.00%
Purchase of Plant’s Capacity, Percentage			32.00%
Hoosier Energy Acquisition [Member] \| Subsequent Event [Member]
Business Combination, Consideration Transferred, Total	$ 20.0
Long-Term Contract for Purchase of Electric Power, Term (Year)	3 years 6 months
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Inventory	$ 17.0
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities, Deferred Revenue	39.0
Hoosier Energy Acquisition [Member] \| Subsequent Event [Member] \| Inventories [Member]
Business Combination, Consideration Transferred, Total	$ 5.4