Quarterly report pursuant to Section 13 or 15(d)

Goodwill and Intangible Assets (Intangible Assets) (Details)

v2.4.1.9
Goodwill and Intangible Assets (Intangible Assets) (Details) (USD $)
6 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Jun. 30, 2014
Indefinite-lived Intangible Assets [Line Items]      
Gross carrying amount - finite lived intangible $ 8,396,000amrk_IntangibleAssetsGrossCarryingAmount   $ 8,396,000amrk_IntangibleAssetsGrossCarryingAmount
Accumulated amortization (5,835,000)us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization   (5,643,000)us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization
Net book value - finite lived intangible 2,561,000us-gaap_IntangibleAssetsNetExcludingGoodwill   2,753,000us-gaap_IntangibleAssetsNetExcludingGoodwill
Amortization expense related to intangible assets 200,000us-gaap_AmortizationOfIntangibleAssets 200,000us-gaap_AmortizationOfIntangibleAssets  
Existing customer relationships      
Indefinite-lived Intangible Assets [Line Items]      
Gross carrying amount - finite lived intangible 5,747,000amrk_IntangibleAssetsGrossCarryingAmount
/ us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis
= us-gaap_CustomerListsMember
  5,747,000amrk_IntangibleAssetsGrossCarryingAmount
/ us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis
= us-gaap_CustomerListsMember
Accumulated amortization (3,640,000)us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization
/ us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis
= us-gaap_CustomerListsMember
  (3,448,000)us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization
/ us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis
= us-gaap_CustomerListsMember
Net book value - finite lived intangible 2,107,000us-gaap_IntangibleAssetsNetExcludingGoodwill
/ us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis
= us-gaap_CustomerListsMember
  2,299,000us-gaap_IntangibleAssetsNetExcludingGoodwill
/ us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis
= us-gaap_CustomerListsMember
Non-compete and other      
Indefinite-lived Intangible Assets [Line Items]      
Estimated useful lives 4 years    
Gross carrying amount - finite lived intangible 2,000,000amrk_IntangibleAssetsGrossCarryingAmount
/ us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis
= amrk_NoncompeteAgreementsAndOtherIntangibleAssetsMember
  2,000,000amrk_IntangibleAssetsGrossCarryingAmount
/ us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis
= amrk_NoncompeteAgreementsAndOtherIntangibleAssetsMember
Accumulated amortization (2,000,000)us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization
/ us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis
= amrk_NoncompeteAgreementsAndOtherIntangibleAssetsMember
  (2,000,000)us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization
/ us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis
= amrk_NoncompeteAgreementsAndOtherIntangibleAssetsMember
Net book value - finite lived intangible 0us-gaap_IntangibleAssetsNetExcludingGoodwill
/ us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis
= amrk_NoncompeteAgreementsAndOtherIntangibleAssetsMember
  0us-gaap_IntangibleAssetsNetExcludingGoodwill
/ us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis
= amrk_NoncompeteAgreementsAndOtherIntangibleAssetsMember
Employment agreement      
Indefinite-lived Intangible Assets [Line Items]      
Estimated useful lives 3 years    
Gross carrying amount - finite lived intangible 195,000amrk_IntangibleAssetsGrossCarryingAmount
/ us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis
= us-gaap_EmploymentContractsMember
  195,000amrk_IntangibleAssetsGrossCarryingAmount
/ us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis
= us-gaap_EmploymentContractsMember
Accumulated amortization (195,000)us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization
/ us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis
= us-gaap_EmploymentContractsMember
  (195,000)us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization
/ us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis
= us-gaap_EmploymentContractsMember
Net book value - finite lived intangible 0us-gaap_IntangibleAssetsNetExcludingGoodwill
/ us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis
= us-gaap_EmploymentContractsMember
  0us-gaap_IntangibleAssetsNetExcludingGoodwill
/ us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis
= us-gaap_EmploymentContractsMember
Purchased intangibles subject to amortization      
Indefinite-lived Intangible Assets [Line Items]      
Gross carrying amount - finite lived intangible 7,942,000amrk_IntangibleAssetsGrossCarryingAmount
/ us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis
= us-gaap_OtherIntangibleAssetsMember
  7,942,000amrk_IntangibleAssetsGrossCarryingAmount
/ us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis
= us-gaap_OtherIntangibleAssetsMember
Accumulated amortization (5,835,000)us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization
/ us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis
= us-gaap_OtherIntangibleAssetsMember
  (5,643,000)us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization
/ us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis
= us-gaap_OtherIntangibleAssetsMember
Net book value - finite lived intangible 2,107,000us-gaap_IntangibleAssetsNetExcludingGoodwill
/ us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis
= us-gaap_OtherIntangibleAssetsMember
  2,299,000us-gaap_IntangibleAssetsNetExcludingGoodwill
/ us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis
= us-gaap_OtherIntangibleAssetsMember
Trade-name      
Indefinite-lived Intangible Assets [Line Items]      
Gross carrying amount 454,000us-gaap_IndefiniteLivedIntangibleAssetsExcludingGoodwill
/ us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis
= us-gaap_TrademarksMember
  454,000us-gaap_IndefiniteLivedIntangibleAssetsExcludingGoodwill
/ us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis
= us-gaap_TrademarksMember
Accumulated amortization 0us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization
/ us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis
= us-gaap_TrademarksMember
  0us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization
/ us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis
= us-gaap_TrademarksMember
Net book value $ 454,000amrk_IndefiniteLivedIntangibleAssetsNet
/ us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis
= us-gaap_TrademarksMember
  $ 454,000amrk_IndefiniteLivedIntangibleAssetsNet
/ us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis
= us-gaap_TrademarksMember
Minimum      
Indefinite-lived Intangible Assets [Line Items]      
Estimated useful lives 4 years    
Minimum | Existing customer relationships      
Indefinite-lived Intangible Assets [Line Items]      
Estimated useful lives 5 years    
Maximum      
Indefinite-lived Intangible Assets [Line Items]      
Estimated useful lives 15 years    
Maximum | Existing customer relationships      
Indefinite-lived Intangible Assets [Line Items]      
Estimated useful lives 15 years