1.0.0.3 false Condensed Consolidated Statements of Income (USD $) In Thousands, except Per Share data false 1 $ false false u000 Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 u002 Divide http://www.xbrl.org/2003/iso4217 USD iso4217 http://www.xbrl.org/2003/instance shares xbrli 0 false 2 $ false false u000 Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 u002 Divide http://www.xbrl.org/2003/iso4217 USD iso4217 http://www.xbrl.org/2003/instance shares xbrli 0 false 3 $ false false u000 Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 u002 Divide http://www.xbrl.org/2003/iso4217 USD iso4217 http://www.xbrl.org/2003/instance shares xbrli 0 false 4 $ false false u000 Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 u002 Divide http://www.xbrl.org/2003/iso4217 USD iso4217 http://www.xbrl.org/2003/instance shares xbrli 0 5 Revenues 3 us-gaap_RevenuesAbstract us-gaap true na duration string No definition available. false false false false false true false false false 1 false false 0 0 false false 2 false false 0 0 false false 3 false false 0 0 false false 4 false false 0 0 false false No definition available. false 6 Coal revenues 4 us-gaap_SalesRevenueGoodsNet us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 true true 662396000 662396 false false 2 true true 601477000 601477 false false 3 true true 1423169000 1423169 false false 4 true true 1627617000 1627617 false false No definition available. No authoritative reference available. false 7 Freight and handling revenues 4 us-gaap_SalesRevenueServicesNet us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true 47592000 47592 false false 2 false true 75709000 75709 false false 3 false true 129091000 129091 false false 4 false true 220896000 220896 false false No definition available. No authoritative reference available. false 8 Other revenues 4 us-gaap_OtherSalesRevenueNet us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true 19258000 19258 false false 2 false true 11218000 11218 false false 3 false true 49960000 49960 false false 4 false true 36640000 36640 false false No definition available. No authoritative reference available. false 9 Total revenues 4 us-gaap_Revenues us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true 729246000 729246 false false 2 false true 688404000 688404 false false 3 false true 1602220000 1602220 false false 4 false true 1885153000 1885153 false false No definition available. No authoritative reference available. true 10 Costs and expenses 3 us-gaap_CostsAndExpensesAbstract us-gaap true na duration string No definition available. false false false false false true false false false 1 false false 0 0 false false 2 false false 0 0 false false 3 false false 0 0 false false 4 false false 0 0 false false No definition available. false 11 Cost of coal sales (exclusive of items shown separately below) 4 us-gaap_CostOfGoodsSold us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true 469451000 469451 false false 2 false true 441092000 441092 false false 3 false true 1039490000 1039490 false false 4 false true 1213999000 1213999 false false No definition available. No authoritative reference available. false 12 Gain on sale of coal reserves 4 anr_GainOnSaleOfCoalReserves anr false na duration monetary The difference between the book value and the sale price of property that has been found to have proven coal reserves. This... false false false false false false false false false 1 false true 0 0 false false 2 false true -11446000 -11446 false false 3 false true 0 0 false false 4 false true -11446000 -11446 false false The difference between the book value and the sale price of property that has been found to have proven coal reserves. This element refers to the gain (loss). No authoritative reference available. false 13 Freight and handling costs 4 us-gaap_ShippingHandlingAndTransportationCosts us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true 47592000 47592 false false 2 false true 75709000 75709 false false 3 false true 129091000 129091 false false 4 false true 220896000 220896 false false No definition available. No authoritative reference available. false 14 Other expenses 4 anr_OtherExpense anr false na duration monetary Amount of other costs of revenues and general expenses not normally included in Other Operating Costs and Expenses. false false false false false false false false false 1 false true 11251000 11251 false false 2 false true 40235000 40235 false false 3 false true 15650000 15650 false false 4 false true 35859000 35859 false false Amount of other costs of revenues and general expenses not normally included in Other Operating Costs and Expenses. No authoritative reference available. false 15 Depreciation, depletion and amortization 4 anr_DepreciationDepletionAndAmortizationRecognizedFromContinuingOperations anr false debit duration monetary The aggregate expense recognized in continuing operations during the current period that allocates the cost of tangible... false false false false false false false false false 1 false true 78246000 78246 false false 2 false true 40155000 40155 false false 3 false true 154803000 154803 false false 4 false true 125548000 125548 false false The aggregate expense recognized in continuing operations during the current period that allocates the cost of tangible assets, intangible assets, or depleting assets to periods that benefit from use of the assets. No authoritative reference available. false 16 Amortization of acquired coal supply agreements, net 4 us-gaap_AmortizationOfIntangibleAssets us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true 57983000 57983 false false 2 false true 0 0 false false 3 false true 57983000 57983 false false 4 false true 0 0 false false No definition available. No authoritative reference available. false 17 Selling, general and administrative expenses (exclusive of depreciation and amortization shown separately above) 4 us-gaap_SellingGeneralAndAdministrativeExpense us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true 83544000 83544 false false 2 false true 20936000 20936 false false 3 false true 122917000 122917 false false 4 false true 56962000 56962 false false No definition available. No authoritative reference available. false 18 Total costs and expenses 4 us-gaap_CostsAndExpenses us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true 748067000 748067 false false 2 false true 606681000 606681 false false 3 false true 1519934000 1519934 false false 4 false true 1641818000 1641818 false false No definition available. No authoritative reference available. true 19 (Loss) income from operations 3 us-gaap_OperatingIncomeLoss us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true -18821000 -18821 false false 2 false true 81723000 81723 false false 3 false true 82286000 82286 false false 4 false true 243335000 243335 false false No definition available. No authoritative reference available. true 20 Other income (expense) 3 anr_OtherIncomeAbstract anr false na duration string No definition available. false false false false false true false false false 1 false false 0 0 false false 2 false false 0 0 false false 3 false false 0 0 false false 4 false false 0 0 false false No definition available. false 21 Interest expense 4 us-gaap_InterestExpense us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true -42835000 -42835 false false 2 false true -9723000 -9723 false false 3 false true -62854000 -62854 false false 4 false true -30225000 -30225 false false No definition available. No authoritative reference available. false 22 Interest income 4 anr_InterestIncome anr false credit duration monetary Interest Income false false false false false false false false false 1 false true 295000 295 false false 2 false true 2725000 2725 false false 3 false true 1275000 1275 false false 4 false true 5702000 5702 false false Interest Income No authoritative reference available. false 23 Loss on early extinguishment of debt 4 us-gaap_GainsLossesOnExtinguishmentOfDebt us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true -5641000 -5641 false false 2 false true -33000 -33 false false 3 false true -5641000 -5641 false false 4 false true -14702000 -14702 false false No definition available. No authoritative reference available. false 24 Miscellaneous income, net 4 anr_MiscellaneousIncomeNet anr false credit duration monetary Miscellaneous Income, Net false false false false false false false false false 1 false true 856000 856 false false 2 false true 481000 481 false false 3 false true 1037000 1037 false false 4 false true 478000 478 false false Miscellaneous Income, Net No authoritative reference available. false 25 Total other expense, net 4 us-gaap_OtherNonoperatingIncomeExpense us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true -47325000 -47325 false false 2 false true -6550000 -6550 false false 3 false true -66183000 -66183 false false 4 false true -38747000 -38747 false false No definition available. No authoritative reference available. true 26 (Loss) income from continuing operations before income taxes 3 us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true -66146000 -66146 false false 2 false true 75173000 75173 false false 3 false true 16103000 16103 false false 4 false true 204588000 204588 false false No definition available. No authoritative reference available. true 27 Income tax benefit (expense) 3 us-gaap_IncomeTaxExpenseBenefit us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true 46172000 46172 false false 2 false true -9066000 -9066 false false 3 false true 27222000 27222 false false 4 false true -39886000 -39886 false false No definition available. No authoritative reference available. false 28 (Loss) income from continuing operations 3 us-gaap_IncomeLossFromContinuingOperations us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true -19974000 -19974 false false 2 false true 66107000 66107 false false 3 false true 43325000 43325 false false 4 false true 164702000 164702 false false No definition available. No authoritative reference available. true 29 Discontinued operations 3 anr_DiscontinuedOperationsAbstract anr false na duration string No definition available. false false false false false true false false false 1 false false 0 0 false false 2 false false 0 0 false false 3 false false 0 0 false false 4 false false 0 0 false false No definition available. false 30 Loss from discontinued operations before income taxes 4 us-gaap_DiscontinuedOperationIncomeLossFromDiscontinuedOperationBeforeIncomeTax us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true -2290000 -2290 false false 2 false true -11768000 -11768 false false 3 false true -11600000 -11600 false false 4 false true -19590000 -19590 false false No definition available. No authoritative reference available. false 31 Gain on sale of discontinued operations 4 us-gaap_DiscontinuedOperationGainLossOnDisposalOfDiscontinuedOperationNetOfTax us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true 0 0 false false 2 false true 13635000 13635 false false 3 false true 0 0 false false 4 false true 13635000 13635 false false No definition available. No authoritative reference available. false 32 Income tax benefit (expense) 4 us-gaap_DiscontinuedOperationTaxEffectOfDiscontinuedOperation us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true 2765000 2765 false false 2 false true -543000 -543 false false 3 false true 5099000 5099 false false 4 false true 1346000 1346 false false No definition available. No authoritative reference available. false 33 Income (loss) from discontinued operations 4 us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTax us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true 475000 475 false false 2 false true 1324000 1324 false false 3 false true -6501000 -6501 false false 4 false true -4609000 -4609 false false No definition available. No authoritative reference available. true 34 Net (loss) income 3 us-gaap_NetIncomeLoss us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 true true -19499000 -19499 false false 2 true true 67431000 67431 false false 3 true true 36824000 36824 false false 4 true true 160093000 160093 false false No definition available. No authoritative reference available. true 35 Basic earnings per share 3 us-gaap_EarningsPerShareBasicAbstract us-gaap true na duration string No definition available. false false false false false true false false false 1 false false 0 0 false false 2 false false 0 0 false false 3 false false 0 0 false false 4 false false 0 0 false false No definition available. false 36 Income (loss) from continuing operations 4 us-gaap_IncomeLossFromContinuingOperationsPerBasicShare us-gaap true na duration decimal No definition available. false false false false false false false false true 1 true true -0.19 -0.19 false false 2 true true 0.95 0.95 false false 3 true true 0.53 0.53 false false 4 true true 2.42 2.42 false false No definition available. No authoritative reference available. false 37 Income (loss) from discontinued operations 4 us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxPerBasicShare us-gaap true na duration decimal No definition available. false false false false false false false false true 1 true true 0 0 false false 2 true true 0.02 0.02 false false 3 true true -0.08 -0.08 false false 4 true true -0.07 -0.07 false false No definition available. No authoritative reference available. false 38 Net income (loss) 4 us-gaap_EarningsPerShareBasic us-gaap true na duration decimal No definition available. false false false false false false false false true 1 true true -0.19 -0.19 false false 2 true true 0.97 0.97 false false 3 true true 0.45 0.45 false false 4 true true 2.35 2.35 false false No definition available. No authoritative reference available. true 39 Diluted earnings per share 3 us-gaap_EarningsPerShareDilutedAbstract us-gaap true na duration string No definition available. false false false false false true false false false 1 false false 0 0 false false 2 false false 0 0 false false 3 false false 0 0 false false 4 false false 0 0 false false No definition available. false 40 Income (loss) from continuing operations 4 us-gaap_IncomeLossFromContinuingOperationsPerDilutedShare us-gaap true na duration decimal No definition available. false false false false false false false false true 1 true true -0.19 -0.19 false false 2 true true 0.91 0.91 false false 3 true true 0.53 0.53 false false 4 true true 2.36 2.36 false false No definition available. No authoritative reference available. false 41 Income (loss) from discontinued operations 4 us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxPerDilutedShare us-gaap true na duration decimal No definition available. false false false false false false false false true 1 true true 0 0 false false 2 true true 0.02 0.02 false false 3 true true -0.08 -0.08 false false 4 true true -0.07 -0.07 false false No definition available. No authoritative reference available. false 42 Net income (loss) 4 us-gaap_EarningsPerShareDiluted us-gaap true na duration decimal No definition available. false false false false false false false false true 1 true true -0.19 -0.19 false false 2 true true 0.93 0.93 false false 3 true true 0.45 0.45 false false 4 true true 2.29 2.29 false false No definition available. No authoritative reference available. true false 4 38 false Thousands UnKnown Hundreds false true