Quarterly report pursuant to Section 13 or 15(d)

Income Taxes (Narrative) (Details)

v2.4.1.9
Income Taxes (Narrative) (Details) (USD $)
 3 Months Ended 6 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2014
Dec. 31, 2013
Jun. 30, 2014
Operating Loss Carryforwards [Line Items]          
Effective tax rate 40.50%us-gaap_EffectiveIncomeTaxRateContinuingOperations 41.90%us-gaap_EffectiveIncomeTaxRateContinuingOperations 40.50%us-gaap_EffectiveIncomeTaxRateContinuingOperations 40.50%us-gaap_EffectiveIncomeTaxRateContinuingOperations  
Valuation allowance $ (300,000)us-gaap_DeferredTaxAssetsValuationAllowance   $ (300,000)us-gaap_DeferredTaxAssetsValuationAllowance    
Deferred Tax Assets, Other 6,000,000us-gaap_DeferredTaxAssetsOther   6,000,000us-gaap_DeferredTaxAssetsOther    
Unrecognized tax benefits 500,000us-gaap_UnrecognizedTaxBenefits   500,000us-gaap_UnrecognizedTaxBenefits    
Penalties and interest expense recognized 400,000us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccrued   400,000us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccrued    
Income taxes receivable from Former Parent 3,139,000us-gaap_DueFromRelatedPartiesCurrent   3,139,000us-gaap_DueFromRelatedPartiesCurrent   3,139,000us-gaap_DueFromRelatedPartiesCurrent
Operating loss related to state and city deferred tax asset 400,000us-gaap_DeferredTaxAssetsOperatingLossCarryforwardsStateAndLocal   400,000us-gaap_DeferredTaxAssetsOperatingLossCarryforwardsStateAndLocal    
Domestic Tax Authority          
Operating Loss Carryforwards [Line Items]          
Income Taxes Receivable 200,000us-gaap_IncomeTaxReceivable
/ us-gaap_IncomeTaxAuthorityAxis
= us-gaap_DomesticCountryMember 		  200,000us-gaap_IncomeTaxReceivable
/ us-gaap_IncomeTaxAuthorityAxis
= us-gaap_DomesticCountryMember 		   
State and Local Jurisdiction          
Operating Loss Carryforwards [Line Items]          
Operating loss carryforwards 6,300,000us-gaap_OperatingLossCarryforwards
/ us-gaap_IncomeTaxAuthorityAxis
= us-gaap_StateAndLocalJurisdictionMember 		  6,300,000us-gaap_OperatingLossCarryforwards
/ us-gaap_IncomeTaxAuthorityAxis
= us-gaap_StateAndLocalJurisdictionMember 		   
Income Tax Sharing Agreement | SGI (Former Parent)          
Operating Loss Carryforwards [Line Items]          
Income taxes receivable from Former Parent $ 3,100,000us-gaap_DueFromRelatedPartiesCurrent
/ us-gaap_RelatedPartyTransactionAxis
= amrk_IncomeTaxSharingAgreementMember
/ us-gaap_RelatedPartyTransactionsByRelatedPartyAxis
= amrk_FormerParentSGIMember 		  $ 3,100,000us-gaap_DueFromRelatedPartiesCurrent
/ us-gaap_RelatedPartyTransactionAxis
= amrk_IncomeTaxSharingAgreementMember
/ us-gaap_RelatedPartyTransactionsByRelatedPartyAxis
= amrk_FormerParentSGIMember