Quarterly report pursuant to Section 13 or 15(d)

Goodwill and Intangible Assets (Narrative) (Details)

v2.4.1.9
Goodwill and Intangible Assets (Narrative) (Details) (USD $)
6 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Jun. 30, 2014
Jun. 30, 2012
Sep. 30, 2012
Finite-Lived Intangible Assets [Line Items]          
Goodwill $ 4,884,000us-gaap_GoodwillGross        
Gross carrying amount - finite lived intangible 8,396,000amrk_IntangibleAssetsGrossCarryingAmount   8,396,000amrk_IntangibleAssetsGrossCarryingAmount    
Amortization expense related to intangible assets $ 200,000us-gaap_AmortizationOfIntangibleAssets $ 200,000us-gaap_AmortizationOfIntangibleAssets      
Spectrum PMI          
Finite-Lived Intangible Assets [Line Items]          
Ownership percentage       80.00%us-gaap_MinorityInterestOwnershipPercentageByParent
/ dei_LegalEntityAxis
= amrk_SpectrumPMIMember
 
Spectrum PMI | Auctentia SL          
Finite-Lived Intangible Assets [Line Items]          
Noncontrolling interest percentage       20.00%us-gaap_MinorityInterestOwnershipPercentageByNoncontrollingOwners
/ dei_LegalEntityAxis
= amrk_SpectrumPMIMember
/ us-gaap_RelatedPartyTransactionsByRelatedPartyAxis
= amrk_AuctentiaSlMember
20.00%us-gaap_MinorityInterestOwnershipPercentageByNoncontrollingOwners
/ dei_LegalEntityAxis
= amrk_SpectrumPMIMember
/ us-gaap_RelatedPartyTransactionsByRelatedPartyAxis
= amrk_AuctentiaSlMember