v3.26.1
Note 2 - Significant Accounting Policies (Details Textual) - USD ($)
$ in Thousands
 3 Months Ended 6 Months Ended 12 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Mar. 31, 2026
Mar. 31, 2025
Sep. 30, 2025
Fair Value Assets and Liabilities, Transfers Between Level One, Level Two and Level Three $ 0       $ 0
Percentage of Gold Held as Good Delivery Gold Bars 100.00%   100.00%    
Maximum Number of Business Days to Transfer Ownership of Gold (Day) 1 day        
Minimum Block of Shares Issued Redeemed Against Gold (in shares) 100,000        
Gain (Loss) on Investments $ 1,659,474 $ 1,900,649 $ 4,350,743 $ 1,831,988  
Gain (Loss) on Sale of Trust Assets to Pay Expenses 2,818 699 4,723 1,316  
Net Realized Gain (Loss) From Gold Distributed for the Redemption of Shares 259,539 34,849 817,154 255,934  
Unrealized Gain (Loss) on Investments 1,397,117 1,865,101 3,528,866 1,574,739  
Liability for Uncertainty in Income Taxes, Current $ 0   $ 0    
Income Tax Examination, Description There were no examinations in progress at period end.        
SPDR Gold Mini Shares Trust [Member]          
Fair Value Assets and Liabilities, Transfers Between Level One, Level Two and Level Three $ 0       $ 0
Percentage of Gold Held as Good Delivery Gold Bars 100.00%   100.00%    
Maximum Number of Business Days to Transfer Ownership of Gold (Day) 1 day        
Minimum Block of Shares Issued Redeemed Against Gold (in shares) 100,000        
Gain (Loss) on Investments $ 1,659,474 1,900,649 $ 4,350,743 1,831,988  
Gain (Loss) on Sale of Trust Assets to Pay Expenses 2,818 699 4,723 1,316  
Net Realized Gain (Loss) From Gold Distributed for the Redemption of Shares 259,539 34,849 817,154 255,934  
Unrealized Gain (Loss) on Investments 1,397,117 $ 1,865,101 3,528,866 $ 1,574,739  
Liability for Uncertainty in Income Taxes, Current $ 0   $ 0    
Income Tax Examination, Description There were no examinations in progress at period end.