Represents the number of shares used to pay interest for the conversion of sahres.

No definition available.

Name:	hnrg_DebtConversionConvertedInstrumentSharesUsedForInterest
Namespace Prefix:	hnrg_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

The number of shares issued in exchange for the original debt being converted in a noncash (or part noncash) transaction. "Part noncash" refers to that portion of the transaction not resulting in cash receipts or payments in the period.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 50
-Paragraph 3
-Publisher FASB
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
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-Section 50
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-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482913/230-10-50-5

+ Details

Name:	us-gaap_DebtConversionConvertedInstrumentSharesIssued1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

The amount of the original debt being converted in a noncash (or part noncash) transaction. "Part noncash" refers to that portion of the transaction not resulting in cash receipts or cash payments in the period.

+ References

+ Details

Name:	us-gaap_DebtConversionOriginalDebtAmount1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The price per share of the conversion feature embedded in the debt instrument.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1B
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481139/470-20-50-1B

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-Name Accounting Standards Codification
-Section 50
-Paragraph 5
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-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481139/470-20-50-5

+ Details

Name:	us-gaap_DebtInstrumentConvertibleConversionPrice1
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:perShareItemType
Balance Type:	na
Period Type:	instant

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22)(a)(1))
-Publisher FASB
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
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-Name Accounting Standards Codification
-Section 50
-Paragraph 1B
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481139/470-20-50-1B

+ Details

Name:	us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Difference between the fair value of payments made and the carrying amount of debt which is extinguished prior to maturity.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Section 45
-Paragraph 28
-Subparagraph (b)
-SubTopic 10
-Topic 230
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-Section 40
-Paragraph 4
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481303/470-50-40-4

+ Details

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

- Definition

The cash inflow from a long-term borrowing made from related parties where one party can exercise control or significant influence over another party; including affiliates, owners or officers and their immediate families, pension trusts, and so forth. Alternate caption: Proceeds from Advances from Affiliates.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 14
-Subparagraph (b)
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-URI https://asc.fasb.org/1943274/2147482740/230-10-45-14

+ Details

Name:	us-gaap_ProceedsFromRelatedPartyDebt
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

Name:	us-gaap_LongtermDebtTypeAxis=hnrg_SeniorUnsecuredConvertibleNotesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_CounterpartyNameAxis=srt_DirectorMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtConversionByUniqueDescriptionAxis=hnrg_ConversionPrice6Point254MaturityDateDecember2028Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtConversionByUniqueDescriptionAxis=hnrg_ConversionPrice6Point15MaturityDateDecember2028Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtConversionByUniqueDescriptionAxis=hnrg_HolderConversionOfAccruedInterestToCommonStockMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_CounterpartyNameAxis=hnrg_NonaffiliatedPartyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtConversionByUniqueDescriptionAxis=hnrg_ConversionPrice6Point254MaturityDateDecember2026Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Note 14 - Convertible Notes (Details Textual) - USD ($) $ / shares in Units, $ in Thousands			3 Months Ended
	Aug. 12, 2022	Jul. 29, 2022	Mar. 31, 2024	Mar. 31, 2023	Aug. 08, 2022
Proceeds from Related Party Debt			$ 5,000	$ 0
Gain (Loss) on Extinguishment of Debt			(853)	0
Debt Conversion, Original Debt, Amount			9,721	$ 0
Senior Unsecured Convertible Notes [Member]
Debt Instrument, Interest Rate, Stated Percentage		8.00%
Senior Unsecured Convertible Notes [Member] \| Director [Member] \| Conversion Price 6 Point 254, Maturity Date December 2028 [Member]
Proceeds from Related Party Debt		$ 5,000	$ 5,000
Debt Instrument, Convertible, Conversion Price (in dollars per share)		$ 6.254
Debt Conversion, Converted Instrument, Shares Issued (in shares)			799,488
Debt Conversion, Converted Instrument, Shares Used for Interest (in shares)			112,570
Gain (Loss) on Extinguishment of Debt			$ (550)
Senior Unsecured Convertible Notes [Member] \| Director [Member] \| Conversion Price 6 Point 15, Maturity Date December 2028 [Member]
Proceeds from Related Party Debt	$ 4,000
Debt Instrument, Interest Rate, Stated Percentage					8.00%
Debt Instrument, Convertible, Conversion Price (in dollars per share)					$ 6.254
Debt Conversion, Converted Instrument, Shares Issued (in shares)			479,693
Debt Conversion, Converted Instrument, Shares Used for Interest (in shares)			67,542
Gain (Loss) on Extinguishment of Debt			$ (300)
Debt Conversion, Original Debt, Amount			$ 3,000
Senior Unsecured Convertible Notes [Member] \| Director [Member] \| Holder Conversion of Accrued Interest to Common Stock [Member]
Debt Conversion, Converted Instrument, Shares Used for Interest (in shares)			57,564
Senior Unsecured Convertible Notes [Member] \| Non-affiliated Party [Member] \| Holder Conversion of Accrued Interest to Common Stock [Member]
Debt Conversion, Converted Instrument, Shares Used for Interest (in shares)			65,041
Senior Unsecured Convertible Notes [Member] \| Non-affiliated Party [Member] \| Conversion Price 6 Point 254, Maturity Date December 2026 [Member]
Proceeds from Related Party Debt	$ 10,000
Debt Instrument, Interest Rate, Stated Percentage	8.00%
Debt Instrument, Convertible, Conversion Price (in dollars per share)	$ 6.15