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v2.4.1.9

Equity Investment in Savoy (Results of Operations for Oil and Gas Producing Activities) (Details) | 12 Months Ended |
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Dec. 31, 2014 bbl | Dec. 31, 2013 bbl | Sep. 30, 2014
Oil [Member] |  |  |
Results of Operations for Oil and Gas Producing Activities, by Geographic Area [Line Items] |  |  |
Reserves, beginning balance | 1,469,000 us-gaap_ProvedDevelopedAndUndevelopedReservesNet / us-gaap_ReserveQuantitiesByTypeOfReserveAxis = us-gaap_OilReservesMember | 700,000 us-gaap_ProvedDevelopedAndUndevelopedReservesNet / us-gaap_ReserveQuantitiesByTypeOfReserveAxis = us-gaap_OilReservesMember |
Extensions and discoveries | 262,000 us-gaap_ProvedDevelopedAndUndevelopedReservesExtensionsDiscoveriesAndAdditions / us-gaap_ReserveQuantitiesByTypeOfReserveAxis = us-gaap_OilReservesMember | 898,000 us-gaap_ProvedDevelopedAndUndevelopedReservesExtensionsDiscoveriesAndAdditions / us-gaap_ReserveQuantitiesByTypeOfReserveAxis = us-gaap_OilReservesMember |
Production | (143,000)us-gaap_ProvedDevelopedAndUndevelopedReservesProduction / us-gaap_ReserveQuantitiesByTypeOfReserveAxis = us-gaap_OilReservesMember | (153,000)us-gaap_ProvedDevelopedAndUndevelopedReservesProduction / us-gaap_ReserveQuantitiesByTypeOfReserveAxis = us-gaap_OilReservesMember |
Revisions to previous estimates | (840,000)us-gaap_ProvedDevelopedAndUndevelopedReservesRevisionsOfPreviousEstimatesIncreaseDecrease / us-gaap_ReserveQuantitiesByTypeOfReserveAxis = us-gaap_OilReservesMember | 24,000 us-gaap_ProvedDevelopedAndUndevelopedReservesRevisionsOfPreviousEstimatesIncreaseDecrease / us-gaap_ReserveQuantitiesByTypeOfReserveAxis = us-gaap_OilReservesMember |
Change in ownership from 45% to 40% | (73,000)hnrg_ProvedDevelopedAndUndevelopedReservesChangeInOwnership / us-gaap_ReserveQuantitiesByTypeOfReserveAxis = us-gaap_OilReservesMember |  |
Reserves, ending balance | 675,000 us-gaap_ProvedDevelopedAndUndevelopedReservesNet / us-gaap_ReserveQuantitiesByTypeOfReserveAxis = us-gaap_OilReservesMember | 1,469,000 us-gaap_ProvedDevelopedAndUndevelopedReservesNet / us-gaap_ReserveQuantitiesByTypeOfReserveAxis = us-gaap_OilReservesMember |
Proved developed reserves | 467,000 us-gaap_ProvedDevelopedReservesVolume / us-gaap_ReserveQuantitiesByTypeOfReserveAxis = us-gaap_OilReservesMember | 746,000 us-gaap_ProvedDevelopedReservesVolume / us-gaap_ReserveQuantitiesByTypeOfReserveAxis = us-gaap_OilReservesMember |
Proved undeveloped reserves (PUDs) | 208,000 us-gaap_ProvedUndevelopedReserveVolume / us-gaap_ReserveQuantitiesByTypeOfReserveAxis = us-gaap_OilReservesMember | 723,000 us-gaap_ProvedUndevelopedReserveVolume / us-gaap_ReserveQuantitiesByTypeOfReserveAxis = us-gaap_OilReservesMember |
Natural Gas Liquids [Member] |  |  |
Results of Operations for Oil and Gas Producing Activities, by Geographic Area [Line Items] |  |  |
Reserves, beginning balance | 99,000 us-gaap_ProvedDevelopedAndUndevelopedReservesNet / us-gaap_ReserveQuantitiesByTypeOfReserveAxis = us-gaap_NaturalGasLiquidsReservesMember | 29,000 us-gaap_ProvedDevelopedAndUndevelopedReservesNet / us-gaap_ReserveQuantitiesByTypeOfReserveAxis = us-gaap_NaturalGasLiquidsReservesMember |
Extensions and discoveries | 14,000 us-gaap_ProvedDevelopedAndUndevelopedReservesExtensionsDiscoveriesAndAdditions / us-gaap_ReserveQuantitiesByTypeOfReserveAxis = us-gaap_NaturalGasLiquidsReservesMember | 58,000 us-gaap_ProvedDevelopedAndUndevelopedReservesExtensionsDiscoveriesAndAdditions / us-gaap_ReserveQuantitiesByTypeOfReserveAxis = us-gaap_NaturalGasLiquidsReservesMember |
Production | (9,000)us-gaap_ProvedDevelopedAndUndevelopedReservesProduction / us-gaap_ReserveQuantitiesByTypeOfReserveAxis = us-gaap_NaturalGasLiquidsReservesMember | (11,000)us-gaap_ProvedDevelopedAndUndevelopedReservesProduction / us-gaap_ReserveQuantitiesByTypeOfReserveAxis = us-gaap_NaturalGasLiquidsReservesMember |
Revisions to previous estimates | (60,000)us-gaap_ProvedDevelopedAndUndevelopedReservesRevisionsOfPreviousEstimatesIncreaseDecrease / us-gaap_ReserveQuantitiesByTypeOfReserveAxis = us-gaap_NaturalGasLiquidsReservesMember | 23,000 us-gaap_ProvedDevelopedAndUndevelopedReservesRevisionsOfPreviousEstimatesIncreaseDecrease / us-gaap_ReserveQuantitiesByTypeOfReserveAxis = us-gaap_NaturalGasLiquidsReservesMember |
Change in ownership from 45% to 40% | (5,000)hnrg_ProvedDevelopedAndUndevelopedReservesChangeInOwnership / us-gaap_ReserveQuantitiesByTypeOfReserveAxis = us-gaap_NaturalGasLiquidsReservesMember |  |
Reserves, ending balance | 39,000 us-gaap_ProvedDevelopedAndUndevelopedReservesNet / us-gaap_ReserveQuantitiesByTypeOfReserveAxis = us-gaap_NaturalGasLiquidsReservesMember | 99,000 us-gaap_ProvedDevelopedAndUndevelopedReservesNet / us-gaap_ReserveQuantitiesByTypeOfReserveAxis = us-gaap_NaturalGasLiquidsReservesMember |
Proved developed reserves | 30,000 us-gaap_ProvedDevelopedReservesVolume / us-gaap_ReserveQuantitiesByTypeOfReserveAxis = us-gaap_NaturalGasLiquidsReservesMember | 60,000 us-gaap_ProvedDevelopedReservesVolume / us-gaap_ReserveQuantitiesByTypeOfReserveAxis = us-gaap_NaturalGasLiquidsReservesMember |
Proved undeveloped reserves (PUDs) | 9,000 us-gaap_ProvedUndevelopedReserveVolume / us-gaap_ReserveQuantitiesByTypeOfReserveAxis = us-gaap_NaturalGasLiquidsReservesMember | 39,000 us-gaap_ProvedUndevelopedReserveVolume / us-gaap_ReserveQuantitiesByTypeOfReserveAxis = us-gaap_NaturalGasLiquidsReservesMember |
Natural Gas [Member] |  |  |
Results of Operations for Oil and Gas Producing Activities, by Geographic Area [Line Items] |  |  |
Reserves, beginning balance | 1,301,000 us-gaap_ProvedDevelopedAndUndevelopedReservesNet / us-gaap_ReserveQuantitiesByTypeOfReserveAxis = us-gaap_NaturalGasReservesMember | 1,108,000 us-gaap_ProvedDevelopedAndUndevelopedReservesNet / us-gaap_ReserveQuantitiesByTypeOfReserveAxis = us-gaap_NaturalGasReservesMember |
Extensions and discoveries | 253,000 us-gaap_ProvedDevelopedAndUndevelopedReservesExtensionsDiscoveriesAndAdditions / us-gaap_ReserveQuantitiesByTypeOfReserveAxis = us-gaap_NaturalGasReservesMember | 442,000 us-gaap_ProvedDevelopedAndUndevelopedReservesExtensionsDiscoveriesAndAdditions / us-gaap_ReserveQuantitiesByTypeOfReserveAxis = us-gaap_NaturalGasReservesMember |
Production | (83,000)us-gaap_ProvedDevelopedAndUndevelopedReservesProduction / us-gaap_ReserveQuantitiesByTypeOfReserveAxis = us-gaap_NaturalGasReservesMember | (96,000)us-gaap_ProvedDevelopedAndUndevelopedReservesProduction / us-gaap_ReserveQuantitiesByTypeOfReserveAxis = us-gaap_NaturalGasReservesMember |
Revisions to previous estimates | (956,000)us-gaap_ProvedDevelopedAndUndevelopedReservesRevisionsOfPreviousEstimatesIncreaseDecrease / us-gaap_ReserveQuantitiesByTypeOfReserveAxis = us-gaap_NaturalGasReservesMember | (153,000)us-gaap_ProvedDevelopedAndUndevelopedReservesRevisionsOfPreviousEstimatesIncreaseDecrease / us-gaap_ReserveQuantitiesByTypeOfReserveAxis = us-gaap_NaturalGasReservesMember |
Change in ownership from 45% to 40% | (65,000)hnrg_ProvedDevelopedAndUndevelopedReservesChangeInOwnership / us-gaap_ReserveQuantitiesByTypeOfReserveAxis = us-gaap_NaturalGasReservesMember |  |
Reserves, ending balance | 450,000 us-gaap_ProvedDevelopedAndUndevelopedReservesNet / us-gaap_ReserveQuantitiesByTypeOfReserveAxis = us-gaap_NaturalGasReservesMember | 1,301,000 us-gaap_ProvedDevelopedAndUndevelopedReservesNet / us-gaap_ReserveQuantitiesByTypeOfReserveAxis = us-gaap_NaturalGasReservesMember |
Proved developed reserves | 292,000 us-gaap_ProvedDevelopedReservesVolume / us-gaap_ReserveQuantitiesByTypeOfReserveAxis = us-gaap_NaturalGasReservesMember | 450,000 us-gaap_ProvedDevelopedReservesVolume / us-gaap_ReserveQuantitiesByTypeOfReserveAxis = us-gaap_NaturalGasReservesMember |
Proved undeveloped reserves (PUDs) | 158,000 us-gaap_ProvedUndevelopedReserveVolume / us-gaap_ReserveQuantitiesByTypeOfReserveAxis = us-gaap_NaturalGasReservesMember | 851,000 us-gaap_ProvedUndevelopedReserveVolume / us-gaap_ReserveQuantitiesByTypeOfReserveAxis = us-gaap_NaturalGasReservesMember |
Savoy [Member] |  |  |
Results of Operations for Oil and Gas Producing Activities, by Geographic Area [Line Items] |  |  |
Equity method investment ownership percentage | 40.00%us-gaap_EquityMethodInvestmentOwnershipPercentage / dei_LegalEntityAxis = hnrg_SavoyMember |  | 45.00%us-gaap_EquityMethodInvestmentOwnershipPercentage / dei_LegalEntityAxis = hnrg_SavoyMember

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- Definition Proved Developed And Undeveloped Reserves, Change In Ownership + References No definition available. + Details
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- Definition The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 323 -SubTopic 10 -Section 50 -Paragraph 3 -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=6382943&loc=d3e33918-111571 + Details
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- Definition Additions to proved reserves that result from (1) extension of the proved acreage of previously discovered (old) reservoirs through additional drilling in periods after discovery and (2) discovery of new fields with proved reserves or of new reservoirs of proved reserves in old fields. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 932 -SubTopic 235 -Section 50 -Paragraph 5 -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=8451039&loc=d3e61831-109447 + Details
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- Definition The net quantity of proved reserves as of the balance sheet date. Proved oil reserves are the estimated quantities of crude oil and natural gas liquids which geological and engineering data demonstrate with reasonable certainty to be recoverable. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 932 -SubTopic 235 -Section 50 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=8451039&loc=d3e61831-109447 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 932 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.4-10.(a)(2)) -URI http://asc.fasb.org/extlink&oid=27015464&loc=d3e511914-122862 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 10 -Paragraph a -Subparagraph 2 -Article 4 + Details
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- Definition Production of proved reserves. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 932 -SubTopic 235 -Section 50 -Paragraph 5 -Subparagraph (e) -URI http://asc.fasb.org/extlink&oid=8451039&loc=d3e61831-109447 + Details
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- Definition Revisions represent changes in previous estimates of proved reserves, either upward or downward, resulting from new information (except for an increase in proved acreage) normally obtained from development drilling and production history or resulting from change in economic factors. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 932 -SubTopic 235 -Section 50 -Paragraph 5 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=8451039&loc=d3e61831-109447 + Details
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- Definition Net quantities of an enterprise's interests in proved developed reserves of either crude oil (including condensate and natural gas liquids), natural gas, synthetic oil and gas, or other nonrenewable natural resource that is intended to be upgraded into synthetic oil and gas as of the beginning and the end of the year. "Net" quantities of reserves include those relating to the enterprise's operating and nonoperating interests in properties. Quantities of reserves relating to royalty interests owned are included in "net" quantities if the necessary information is available to the enterprise. "Net" quantities does not include reserves relating to interests of others in properties owned by the enterprise. The unit of measure for reserve quantities is defined as "barrels" for oil and synthetic oil reserves or "cubic feet" or "cubic meters" for natural gas and synthetic gas reserves. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 932 -SubTopic 235 -Section 50 -Paragraph 4 -URI http://asc.fasb.org/extlink&oid=8451039&loc=d3e61797-109447 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 932 -SubTopic 235 -Section 50 -Paragraph 9 -URI http://asc.fasb.org/extlink&oid=8451039&loc=d3e61884-109447 + Details
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