Note 3 - Trust Expenses (Details Textual) - USD ($)		12 Months Ended
	Jan. 31, 2022	Dec. 31, 2021
Sponsors Fee Annualized Accrual Rate Based on Daily Net Asset Value		0.25%
Maximum [Member]
Legal Fees Per Year		$ 100,000
Maximum [Member] | Subsequent Event [Member]
Legal Fees Per Year	$ 500,000