Summary of Significant Accounting Policies (Derivative Instruments) (Details) (USD $)
In Thousands, unless otherwise specified |
3 Months Ended | 9 Months Ended | ||
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Mar. 31, 2015
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Mar. 31, 2014
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Mar. 31, 2015
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Mar. 31, 2014
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Derivative [Line Items] | ||||
Realized gain (loss) on future commodity contracts, net | $ (10,309)us-gaap_DerivativeGainLossOnDerivativeNet | $ (21,122)us-gaap_DerivativeGainLossOnDerivativeNet | $ (44,831)us-gaap_DerivativeGainLossOnDerivativeNet | $ (31,144)us-gaap_DerivativeGainLossOnDerivativeNet |
Futures Commodity And Forwards Contracts And Open Purchase And Sale Commitments [Member] | ||||
Derivative [Line Items] | ||||
Unrealized loss on open future commodity and forward contracts and open sale and purchase commitments, net |
(12,866)us-gaap_UnrealizedGainLossOnDerivatives / us-gaap_DerivativeInstrumentRiskAxis = amrk_FuturesCommodityAndForwardsContractsAndOpenPurchaseAndSaleCommitmentsMember |
(19,373)us-gaap_UnrealizedGainLossOnDerivatives / us-gaap_DerivativeInstrumentRiskAxis = amrk_FuturesCommodityAndForwardsContractsAndOpenPurchaseAndSaleCommitmentsMember |
(2,582)us-gaap_UnrealizedGainLossOnDerivatives / us-gaap_DerivativeInstrumentRiskAxis = amrk_FuturesCommodityAndForwardsContractsAndOpenPurchaseAndSaleCommitmentsMember |
(21,212)us-gaap_UnrealizedGainLossOnDerivatives / us-gaap_DerivativeInstrumentRiskAxis = amrk_FuturesCommodityAndForwardsContractsAndOpenPurchaseAndSaleCommitmentsMember |
Commodity Contract | ||||
Derivative [Line Items] | ||||
Realized gain (loss) on future commodity contracts, net |
$ 2,557us-gaap_DerivativeGainLossOnDerivativeNet / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_CommodityContractMember |
$ (1,749)us-gaap_DerivativeGainLossOnDerivativeNet / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_CommodityContractMember |
$ (42,249)us-gaap_DerivativeGainLossOnDerivativeNet / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_CommodityContractMember |
$ (9,932)us-gaap_DerivativeGainLossOnDerivativeNet / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_CommodityContractMember |
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- Definition
Amount of increase (decrease) in the fair value of derivatives recognized in the income statement. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition
The net change in the difference between the fair value and the carrying value, or in the comparative fair values, of derivative instruments, including options, swaps, futures, and forward contracts, held at each balance sheet date, that was included in earnings for the period. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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