Amount of debt with maximum interest rate

No definition available.

Name:	hnrg_AmountOfDebtWithMaximumInterestRate
Namespace Prefix:	hnrg_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Debt service coverage ratio

+ References

No definition available.

+ Details

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Balance Type:	na
Period Type:	instant

- Definition

Leverage Ratio

+ References

No definition available.

+ Details

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Balance Type:	na
Period Type:	instant

- Definition

Liquidity

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
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- Definition

The net increase(decrease) in interest income during the period representing the allocation of deferred loan origination fees less deferred loan origination costs using the effective interest method over the term of the debt arrangement to which they pertain taking into account the effect of prepayments.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of the fee that accompanies borrowing money under the debt instrument.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
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-Paragraph 1
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-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Effective interest rate for the funds borrowed under the debt agreement considering interest compounding and original issue discount or premium.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
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-Paragraph 6
-Subparagraph (a)
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Balance Type:	na
Period Type:	instant

- Definition

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.

+ References

No definition available.

+ Details

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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Date when the debt instrument is scheduled to be fully repaid, in CCYY-MM-DD format.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
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+ Details

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Balance Type:	na
Period Type:	duration

- Definition

Amount of unused borrowing capacity under the long-term financing arrangement that is available to the entity as of the balance sheet date.

+ References

+ Details

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

- Definition

Fair value of the amount outstanding under the credit facility.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 10
-URI http://asc.fasb.org/extlink&oid=109250915&loc=d3e13433-108611

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- Details

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- Details

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Bank Debt (Narrative) (Details) - USD ($) $ in Millions	6 Months Ended
Bank Debt (Narrative) (Details) - USD ($) $ in Millions	Jun. 30, 2019	Dec. 31, 2018	May 21, 2018
Debt Instrument [Line Items]
Leverage ratio	220.00%
Debt service coverage ratio	225.00%
Interest rate effective percentage	5.91%
Credit Agreement [Member]
Debt Instrument [Line Items]
Closing costs of debt	$ 8.8
Deferred financing costs expensed	6.3	$ 7.4
Credit agreement, amount outstanding	173.0
Borrowing capacity	65.0
Liquidity	$ 73.0
Debt, interest rate spread on variable rate	3.50%
Interest rate effective percentage	6.00%
Minimum [Member] \| Credit Agreement [Member]
Debt Instrument [Line Items]
Debt service coverage ratio	125.00%
London Interbank Offered Rate (LIBOR) [Member] \| Minimum [Member] \| Credit Agreement [Member]
Debt Instrument [Line Items]
Debt, interest rate spread on variable rate	3.00%
London Interbank Offered Rate (LIBOR) [Member] \| Maximum [Member] \| Credit Agreement [Member]
Debt Instrument [Line Items]
Debt, interest rate spread on variable rate	4.50%
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Amount of debt with maximum interest rate	$ 53.0
Revolving Credit Facility [Member] \| Credit Agreement [Member]
Debt Instrument [Line Items]
Credit agreement, amount outstanding	$ 55.0		$ 120.0
Debt maturity date	May 21, 2022
Term Loan [Member] \| Credit Agreement [Member]
Debt Instrument [Line Items]
Credit agreement, amount outstanding	$ 118.0