v3.25.3
Fair Value of ETC - Summary of changes in quantity of ETC and the respective fair value (Detail)
$ in Thousands
 3 Months Ended 9 Months Ended 12 Months Ended
Sep. 30, 2025
USD ($)
ETC
Sep. 30, 2024
USD ($)
Sep. 30, 2025
USD ($)
ETC
Sep. 30, 2024
USD ($)
ETC
Dec. 31, 2024
USD ($)
ETC
Fair Value Disclosures [Abstract]          
Investment Owned, Balance | ETC     11,263,626.2550315 11,548,776.1723 11,548,776.1723
ETC contributed | ETC     0   0
ETC distributed for Sponsor's Fee, related party | ETC     (208,664.57666045)   (285,149.91726843)
Net change in unrealized (depreciation) appreciation on investment in ETC | ETC     0   0
Net realized gain on investment in ETC | ETC     0   0
Investment Owned, Balance | ETC 11,054,961.67837105   11,054,961.67837105   11,263,626.2550315
Investment Owned, at Fair Value | $     $ 283,055 $ 253,958 $ 253,958
ETC contributed | $     0   0
ETC distributed for Sponsor's Fee, related party | $     (4,130)   (7,157)
Net change in unrealized appreciation on investment in ETC | $ $ 17,154 $ (45,236) (78,289) (29,389) 31,251
Net realized gain on investment in ETC | $ 912 $ 896 2,554 $ 3,782 5,003
Investment Owned, at Fair Value | $ $ 203,190   $ 203,190   $ 283,055