1.0.0.3 false Consolidated Statements of Operations (USD $) In Thousands, except Per Share data false 1 $ false false USD Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 USDEPS Divide http://www.xbrl.org/2003/iso4217 USD iso4217 http://www.xbrl.org/2003/instance shares xbrli 0 false 2 $ false false USD Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 USDEPS Divide http://www.xbrl.org/2003/iso4217 USD iso4217 http://www.xbrl.org/2003/instance shares xbrli 0 false 3 $ false false USD Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 USDEPS Divide http://www.xbrl.org/2003/iso4217 USD iso4217 http://www.xbrl.org/2003/instance shares xbrli 0 3 Revenues: 1 us-gaap_SalesRevenueNetAbstract 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 No definition available. false 4 Coal revenues 2 us-gaap_SalesRevenueGoodsNet us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 true true 2210629000 2210629 false false 2 true true 2140367000 2140367 false false 3 true true 1558665000 1558665 false false No definition available. No authoritative reference available. false 5 Freight and handling revenues 2 us-gaap_SalesRevenueServicesNet us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true 189874000 189874 false false 2 false true 279853000 279853 false false 3 false true 205086000 205086 false false No definition available. No authoritative reference available. false 6 Other revenues 2 us-gaap_OtherSalesRevenueNet us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true 95004000 95004 false false 2 false true 48533000 48533 false false 3 false true 42403000 42403 false false No definition available. No authoritative reference available. true 7 Total revenues 2 us-gaap_SalesRevenueNet us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true 2495507000 2495507 false false 2 false true 2468753000 2468753 false false 3 false true 1806154000 1806154 false false No definition available. No authoritative reference available. true 8 Costs and expenses: 1 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 No definition available. false 9 Cost of coal sales (exclusive of items shown separately below) 2 us-gaap_CostOfGoodsSold us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true 1616905000 1616905 false false 2 false true 1627960000 1627960 false false 3 false true 1284840000 1284840 false false No definition available. No authoritative reference available. false 10 Gain on sale of coal reserves 2 anr_GainOnSaleOfCoalReserves anr false credit 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 -12936000 -12936 false false 3 false true 0 0 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 11 Freight and handling costs 2 us-gaap_CostOfServices us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true 189874000 189874 false false 2 false true 279853000 279853 false false 3 false true 205086000 205086 false false No definition available. No authoritative reference available. false 12 Other expenses 2 anr_OtherExpense anr false debit 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 21016000 21016 false false 2 false true 91461000 91461 false false 3 false true 22725000 22725 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 13 Depreciation, depletion and amortization 2 us-gaap_DepreciationAndAmortization us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true 252395000 252395 false false 2 false true 164969000 164969 false false 3 false true 153987000 153987 false false No definition available. No authoritative reference available. false 14 Amortization of acquired coal supply agreements, net 2 us-gaap_AmortizationOfIntangibleAssets us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true 127608000 127608 false false 2 false true 0 0 false false 3 false true 0 0 false false No definition available. No authoritative reference available. false 15 Selling, general and administrative expenses (exclusive of depreciation and amortization shown separately above) 2 us-gaap_SellingGeneralAndAdministrativeExpense us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true 170414000 170414 false false 2 false true 71923000 71923 false false 3 false true 58485000 58485 false false No definition available. No authoritative reference available. true 16 Total costs and expenses 2 us-gaap_CostsAndExpenses us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true 2378212000 2378212 false false 2 false true 2223230000 2223230 false false 3 false true 1725123000 1725123 false false No definition available. No authoritative reference available. true 17 Income from operations 1 us-gaap_OperatingIncomeLoss us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true 117295000 117295 false false 2 false true 245523000 245523 false false 3 false true 81031000 81031 false false No definition available. No authoritative reference available. true 18 Other income (expense): 1 us-gaap_NonoperatingIncomeExpenseAbstract 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 No definition available. false 19 Interest expense 2 us-gaap_InterestExpense us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true -82825000 -82825 false false 2 false true -39812000 -39812 false false 3 false true -40366000 -40366 false false No definition available. No authoritative reference available. false 20 Interest income 2 us-gaap_InvestmentIncomeInterest us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true 1769000 1769 false false 2 false true 7351000 7351 false false 3 false true 2266000 2266 false false No definition available. No authoritative reference available. false 21 Loss on early extinguishment of debt 2 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 -14702000 -14702 false false 3 false true 0 0 false false No definition available. No authoritative reference available. false 22 Gain on termination of Cliffs' merger, net 2 us-gaap_GainLossOnContractTermination 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 56315000 56315 false false 3 false true 0 0 false false No definition available. No authoritative reference available. false 23 Miscellaneous income (expense), net 2 us-gaap_OtherNonoperatingIncomeExpense us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true 3186000 3186 false false 2 false true -3834000 -3834 false false 3 false true -93000 -93 false false No definition available. No authoritative reference available. true 24 Total other income (expense), net 2 us-gaap_NonoperatingIncomeExpense us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true -83511000 -83511 false false 2 false true 5318000 5318 false false 3 false true -38193000 -38193 false false No definition available. No authoritative reference available. true 25 Income from continuing operations before income taxes 1 us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true 33784000 33784 false false 2 false true 250841000 250841 false false 3 false true 42838000 42838 false false No definition available. No authoritative reference available. false 26 Income tax (expense) benefit 1 us-gaap_IncomeTaxExpenseBenefit us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true 33023000 33023 false false 2 false true -52242000 -52242 false false 3 false true -9965000 -9965 false false No definition available. No authoritative reference available. true 27 Income from continuing operations 1 us-gaap_IncomeLossFromContinuingOperations us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true 66807000 66807 false false 2 false true 198599000 198599 false false 3 false true 32873000 32873 false false No definition available. No authoritative reference available. false 28 Discontinued operations 1 anr_DiscontinuedOperationsAbstract anr false na duration string Discontinued operations. 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 Discontinued operations. false 29 Loss from discontinued operations 2 us-gaap_DiscontinuedOperationIncomeLossFromDiscontinuedOperationBeforeIncomeTax us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true -14278000 -14278 false false 2 false true -27873000 -27873 false false 3 false true -6653000 -6653 false false No definition available. No authoritative reference available. false 30 Mine closure/asset impairment charges 2 us-gaap_DiscontinuedOperationProvisionForLossGainOnDisposalNetOfTax us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true 0 0 false false 2 false true -30172000 -30172 false false 3 false true 0 0 false false No definition available. No authoritative reference available. false 31 Gain on sale of discontinued operations 2 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 13622000 13622 false false 3 false true 0 0 false false No definition available. No authoritative reference available. false 32 Income tax benefit 2 us-gaap_DiscontinuedOperationTaxEffectOfDiscontinuedOperation us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true 5476000 5476 false false 2 false true 11035000 11035 false false 3 false true 1335000 1335 false false No definition available. No authoritative reference available. true 33 Loss from discontinued operations 2 us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTax us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true -8802000 -8802 false false 2 false true -33388000 -33388 false false 3 false true -5318000 -5318 false false No definition available. No authoritative reference available. true 34 Net income 1 us-gaap_ProfitLoss us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true 58005000 58005 false false 2 false true 165211000 165211 false false 3 false true 27555000 27555 false false No definition available. No authoritative reference available. false 35 Less : Net loss from discontinued operations attributable to noncontrolling interest 1 us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToNoncontrollingInterest us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true 0 0 false false 2 false true -490000 -490 false false 3 false true -179000 -179 false false No definition available. No authoritative reference available. true 36 Net income attributable to Alpha Natural Resources, Inc. 1 us-gaap_NetIncomeLoss us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true 58005000 58005 false false 2 false true 165701000 165701 false false 3 false true 27734000 27734 false false No definition available. No authoritative reference available. true 37 Amounts attributable to Alpha Natural Resources, Inc. 1 us-gaap_NetIncomeLossAbstract 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 No definition available. false 38 Income from continuing operations, net of tax 2 us-gaap_IncomeLossFromContinuingOperations us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true 66807000 66807 false false 2 false true 198599000 198599 false false 3 false true 32873000 32873 false false No definition available. No authoritative reference available. false 39 Loss from discontinued operations, net of tax 2 us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true -8802000 -8802 false false 2 false true -32898000 -32898 false false 3 false true -5139000 -5139 false false No definition available. No authoritative reference available. true 40 Net income attributable to Alpha Natural Resources, Inc. 2 us-gaap_NetIncomeLoss us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 true true 58005000 58005 false false 2 true true 165701000 165701 false false 3 true true 27734000 27734 false false No definition available. No authoritative reference available. true 41 Basic earnings per share: 1 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 No definition available. false 42 Income from continuing operations attributable to Alpha Natural Resources, Inc. 2 us-gaap_IncomeLossFromContinuingOperationsPerBasicShare us-gaap true na duration decimal No definition available. false false false false false false false false true 1 true true 0.74 0.74 false false 2 true true 2.9 2.9 false false 3 true true 0.51 0.51 false false No definition available. No authoritative reference available. false 43 Loss from discontinued operations attributable to Alpha Natural Resources, Inc. 2 us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxPerBasicShare us-gaap true na duration decimal No definition available. false false false false false false false false true 1 true true -0.1 -0.1 false false 2 true true -0.48 -0.48 false false 3 true true -0.08 -0.08 false false No definition available. No authoritative reference available. true 44 Net income attributable to Alpha Natural Resources, Inc. 2 us-gaap_EarningsPerShareBasic us-gaap true na duration decimal No definition available. false false false false false false false false true 1 true true 0.64 0.64 false false 2 true true 2.42 2.42 false false 3 true true 0.43 0.43 false false No definition available. No authoritative reference available. true 45 Diluted earnings per share: 1 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 No definition available. false 46 Income from continuing operations attributable to Alpha Natural Resources, Inc. 2 us-gaap_IncomeLossFromContinuingOperationsPerDilutedShare us-gaap true na duration decimal No definition available. false false false false false false false false true 1 true true 0.73 0.73 false false 2 true true 2.83 2.83 false false 3 true true 0.51 0.51 false false No definition available. No authoritative reference available. false 47 Loss from discontinued operations attributable to Alpha Natural Resources, Inc. 2 us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxPerDilutedShare us-gaap true na duration decimal No definition available. false false false false false false false false true 1 true true -0.1 -0.1 false false 2 true true -0.47 -0.47 false false 3 true true -0.08 -0.08 false false No definition available. No authoritative reference available. true 48 Net income attributable to Alpha Natural Resources, Inc. 2 us-gaap_EarningsPerShareDiluted us-gaap true na duration decimal No definition available. false false false false false false false false true 1 true true 0.63 0.63 false false 2 true true 2.36 2.36 false false 3 true true 0.43 0.43 false false No definition available. No authoritative reference available. true false 3 46 false Thousands UnKnown Hundreds false true