v3.26.1
Financial Highlights Per Share Performance - Summary of per share data (Detail) - $ / shares
12 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2024
Per Share Data:      
Principal Market NAV, beginning of year $ 7.25 $ 6.37 $ 9.22
Net (decrease) increase in net assets from investment operations:      
Net investment loss (0.16) (0.19) (0.17)
Net realized and unrealized (loss) gain (3.7) 1.07 (2.68)
Net (decrease) increase in net assets resulting from operations (3.86) 0.88 (2.85)
Principal Market NAV, end of year $ 3.39 $ 7.25 $ 6.37
Total return (53.24%) 13.81% (30.91%)
Ratios to average net assets:      
Net investment loss (2.50%) (2.50%) (2.50%)
Expenses (2.50%) (2.50%) (2.50%)