v3.25.1
Fair Value of ZEN - Summary of changes in quantity of ZEN and respective fair value (Detail)
$ in Thousands
 3 Months Ended 6 Months Ended 12 Months Ended
Mar. 31, 2025
USD ($)
Horizen
Mar. 31, 2024
USD ($)
Mar. 31, 2025
USD ($)
Horizen
Mar. 31, 2024
USD ($)
Horizen
Sep. 30, 2024
USD ($)
Horizen
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 Owned, Balance, Contracts | Horizen     586,285.79535365 601,138.55454194 601,138.55454194
ZEN contributed | Horizen     377,718.6458723   0
ZEN distributed for Sponsor's Fee, related party | Horizen     (9,608.67659242)   (14,852.75918829)
Net change in unrealized depreciation on investment in ZEN | Horizen     0   0
Net realized loss on investment in ZEN | Horizen     0   0
Investment Owned, Balance, Contracts | Horizen 954,395.76463353   954,395.76463353   586,285.79535365
Investment Owned, at Fair Value | $     $ 4,767 $ 4,671 $ 4,671
ZEN contributed | $     6,493   0
ZEN distributed for Sponsor's Fee, related party | $     (146)   (140)
Net change in unrealized depreciation on investment in ZEN | $ $ (18,118) $ 3,419 (2,661) 4,286 400
Net realized loss on investment in ZEN | $ (21) $ (37) (45) $ (78) (164)
Investment Owned, at Fair Value | $ $ 8,408   $ 8,408   $ 4,767