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Data Type:	xbrli:monetaryItemType
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Amount of depreciation and amortization expense, net of tax attributable to disposal group, including, but not limited to, discontinued operation.

No definition available.

Name:	hnrg_DisposalGroupIncludingDiscontinuedOperationDepreciationAndAmortizationNetOfTax
Namespace Prefix:	hnrg_
Data Type:	xbrli:monetaryItemType
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Represents number of day right of first refusal.

No definition available.

Name:	hnrg_DisposalGroupIncludingDiscontinuedOperationRightOfFirstRefusalNumberOfDays
Namespace Prefix:	hnrg_
Data Type:	xbrli:durationItemType
Balance Type:	na
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Amount of consideration received or receivable for the disposal of assets and liabilities, including discontinued operation.

No definition available.

Name:	us-gaap_DisposalGroupIncludingDiscontinuedOperationConsideration
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Amount of depreciation and amortization expense attributable to disposal group, including, but not limited to, discontinued operation.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 205
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 5B
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483499/205-20-50-5B

Name:	us-gaap_DisposalGroupIncludingDiscontinuedOperationDepreciationAndAmortization
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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.

No definition available.