A-Mark Precious Metals, Inc. Quarterly report pursuant to Section 13 or 15(d)

Hedging Transactions (Narrative) (Details) (USD $)	3 Months Ended		9 Months Ended
Hedging Transactions (Narrative) (Details) (USD $)	Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2015	Mar. 31, 2014	Jun. 30, 2014
Derivative [Line Items]
Realized gain (loss) on future commodity contracts, net	$ (10,309,000)	$ (21,122,000)	$ (44,831,000)	$ (31,144,000)
Derivative usual settlement period			2 days
Derivative open positions expected settlement period			30 days
Unrealized losses on foreign exchange	(123,000)	(60,000)	(207,000)	0
Foreign Exchange
Derivative [Line Items]
Open inventory sale commitments	300,000		300,000		2,700,000
Forward contracts
Derivative [Line Items]
Open inventory sale commitments	$ 2,200,000		$ 2,200,000		$ 3,800,000