Receivables (Loans Receivable and Credit Quality Indicators) (Details)	12 Months Ended
	Jun. 30, 2015 USD ($) loan class	Jun. 30, 2014 USD ($) loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of loans | loan	1	0
Classes of receivables | class	3
Secured loan	$ 49,316,000	$ 41,261,000
Secured loan, percentage	100.00%	100.00%
Secured loans (current)	$ 48,666,000	$ 41,261,000
Loan-to-value of More than 100%
Accounts, Notes, Loans and Financing Receivable [Line Items]
Secured loans (current)	$ 175,600
Secured loans (current), percentage	0.40%
Bullion and Numismatic
Accounts, Notes, Loans and Financing Receivable [Line Items]
Secured loan	$ 48,466,000	$ 41,261,000
Secured loan, percentage	98.30%	100.00%
Secured loans (current)	$ 48,466,000	$ 41,261,000
Secured loans (current), percentage	100.00%	100.00%
Bullion and Numismatic | Loan-to-value of 75% or more
Accounts, Notes, Loans and Financing Receivable [Line Items]
Secured loans (current)	$ 17,153,000	$ 11,950,000
Secured loans (current), percentage	35.40%	29.00%
Bullion and Numismatic | Loan-to-value of less than 75%
Accounts, Notes, Loans and Financing Receivable [Line Items]
Secured loans (current)	$ 31,313,000	$ 29,311,000
Secured loans (current), percentage	64.60%	71.00%
Bullion
Accounts, Notes, Loans and Financing Receivable [Line Items]
Secured loan	$ 16,250,000	$ 17,361,000
Secured loan, percentage	33.00%	42.10%
Numismatic and semi numismatic
Accounts, Notes, Loans and Financing Receivable [Line Items]
Secured loan	$ 32,216,000	$ 23,900,000
Secured loan, percentage	65.30%	57.90%
Other pledged assets
Accounts, Notes, Loans and Financing Receivable [Line Items]
Secured loan	$ 850,000	$ 0
Secured loan, percentage	1.70%	0.00%
Minimum
Accounts, Notes, Loans and Financing Receivable [Line Items]
Credit quality indicator Loan-to-value threshold percentage	75.00%
Maximum
Accounts, Notes, Loans and Financing Receivable [Line Items]
Secured loans (current), percentage	100.00%
Secured Loans-to-Value Percentage	100.00%