| Secured Loans Receivable - Schedule of Classes for Financing Receivables (Details) - USD ($) $ in Thousands | Jun. 30, 2021 | Jun. 30, 2020 | 
|---|---|---|
| Accounts, Notes, Loans and Financing Receivable [Line Items] | ||
| Secured loans | $ 112,968 | $ 63,710 | 
| Secured loan, percentage | 100.00% | 100.00% | 
| Bullion | ||
| Accounts, Notes, Loans and Financing Receivable [Line Items] | ||
| Secured loans | $ 88,332 | $ 36,445 | 
| Secured loan, percentage | 78.20% | 57.20% | 
| Numismatic and Semi-numismatic | ||
| Accounts, Notes, Loans and Financing Receivable [Line Items] | ||
| Secured loans | $ 24,636 | $ 27,265 | 
| Secured loan, percentage | 21.80% | 42.80% | 
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- Definition The percentage that a balance of a given type of loan receivable is to the total balance outstanding. No definition available. 
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available. 
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- Definition Amount, after allowance for credit loss, of financing receivable. Excludes financing receivable covered under loss sharing agreement. Reference 1: http://www.xbrl.org/2003/role/disclosureRef 
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