Note 2 - Significant Accounting Policies - Activity in Number and Value of Shares Created and Redeemed (Details) - USD ($) $ in Thousands |
3 Months Ended | 6 Months Ended | ||
|---|---|---|---|---|
Mar. 31, 2026 |
Mar. 31, 2025 |
Mar. 31, 2026 |
Mar. 31, 2025 |
|
| Activity in Number of Shares Created and Redeemed: | ||||
| Creations (in shares) | 39,000,000 | 51,900,000 | 92,300,000 | 81,500,000 |
| Redemptions (in shares) | (46,800,000) | (30,400,000) | (79,600,000) | (59,500,000) |
| Net Change in Number of Shares Created and Redeemed (in shares) | 12,700,000 | 22,000,000 | ||
| Activity in Value of Shares Created and Redeemed: | ||||
| Creations | $ 17,672,805 | $ 13,919,642 | $ 38,199,177 | $ 21,193,982 |
| Redemptions | $ (21,013,472) | $ (7,955,231) | (33,338,524) | (15,114,312) |
| Net change in Value of Shares Created and Redeemed | $ 4,860,653 | $ 6,079,671 | ||
| X | ||||||||||
- Definition Represents the activity in number of shares created and redeemed. No definition available.
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| X | ||||||||||
- Definition Represents the activity in value of shares created and redeemed. No definition available.
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| X | ||||||||||
- Definition The shares issued and outstanding net increase decrease. No definition available.
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| X | ||||||||||
- Definition The value of net increase (decrease) in shares issued and outstanding. No definition available.
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| X | ||||||||||
- Definition Number of new stock issued during the period. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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| X | ||||||||||
- Definition Equity impact of the value of new stock issued during the period. Includes shares issued in an initial public offering or a secondary public offering. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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| X | ||||||||||
- Definition Number of shares that have been repurchased and retired during the period. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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| X | ||||||||||
- Definition Equity impact of the value of stock that has been repurchased and retired during the period. The excess of the purchase price over par value can be charged against retained earnings (once the excess is fully allocated to additional paid in capital). Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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