v3.26.1
Fair Value of ZEN - Summary of changes in quantity of ZEN and respective fair value (Detail)
$ in Thousands
 3 Months Ended 6 Months Ended
Jun. 30, 2026
USD ($)
Horizen
Jun. 30, 2025
USD ($)
Horizen
Jun. 30, 2026
USD ($)
Horizen
Jun. 30, 2025
USD ($)
Horizen
Dec. 31, 2025
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]          
Investment, Type [Extensible Enumeration] Investment in ZEN [Member] Investment in ZEN [Member] Investment in ZEN [Member] Investment in ZEN [Member] Investment in ZEN [Member]
Investment Owned, Balance, Contracts | Horizen     949,408.87165001 889,400.61619664  
ZEN contributed | Horizen     0 83,720.15209896  
ZEN distributed for Sponsor's Fee, related party | Horizen     (11,697.80928309) (11,670.61417119)  
Net change in unrealized appreciation/depreciation on investment in ZEN | Horizen     0 0  
Net realized loss on investment in ZEN | Horizen     0 0  
Investment Owned, Balance, Contracts | Horizen 937,711.06236692 961,450.15412441 937,711.06236692 961,450.15412441  
Investment Owned, at Fair Value | $     $ 8,673 $ 25,713  
ZEN contributed | $     0 1,030  
ZEN distributed for Sponsor's Fee, related party | $     (74) (142)  
Net change in unrealized appreciation/depreciation on investment in ZEN | $ $ (1,421) $ (1,305) (4,673) (19,423)  
Net realized loss on investment in ZEN | $ (79) (61) (148) (82)  
Investment Owned, at Fair Value | $ $ 3,778 $ 7,096 $ 3,778 $ 7,096