Quarterly report [Sections 13 or 15(d)]

Long-Term Investments - Schedule of Carrying Value and Ownership Percentage of Investment (Parenthetical) (Details)

v3.25.1
Long-Term Investments - Schedule of Carrying Value and Ownership Percentage of Investment (Parenthetical) (Details)
Mar. 31, 2025
Feb. 28, 2025
Jun. 30, 2024
AMS Holding, LLC      
Schedule Of Equity And Cost Method Investments [Line Items]      
Ownership percentage [1] 10.00%   33.30%
AMS Holding, LLC | Spectrum Group International, Inc. and Pinehurst Coin Exchange, Inc.      
Schedule Of Equity And Cost Method Investments [Line Items]      
Ownership percentage 10.00%    
AMS Holding, LLC | APS Investment, LLC      
Schedule Of Equity And Cost Method Investments [Line Items]      
Ownership percentage 10.00%    
APS Investment, LLC      
Schedule Of Equity And Cost Method Investments [Line Items]      
Ownership percentage   33.30%  
APS Investment, LLC | Spectrum Group International, Inc. and Pinehurst Coin Exchange, Inc.      
Schedule Of Equity And Cost Method Investments [Line Items]      
Ownership percentage   100.00%  
APS Investment, LLC | Pinehurst Coin Exchange, Inc.      
Schedule Of Equity And Cost Method Investments [Line Items]      
Ownership percentage 33.30%    
APS Investment, LLC | Stack's Bowers Numismatics, LLC      
Schedule Of Equity And Cost Method Investments [Line Items]      
Ownership percentage 33.30%    
[1] APS Investment, LLC is a holding company that as of March 31, 2025 owned a 10% equity interest in AMS Holding, LLC. A-Mark, Pinehurst Coin Exchange, Inc. and Stack's Bowers Galleries each own a one-third equity interest in APS Investment, LLC. In February 2025, the Company acquired both SGI, the parent of Stack's Bowers Galleries and Pinehurst; as a result, the Company owned 100% of APS Investment, LLC and therefore a 10% equity interest of AMS Holding, LLC as of March 31, 2025. Prior to the acquisitions of SGI and Pinehurst in February 2025, the Company owned a 33.3% equity interest in APS Investment, LLC.