v3.26.1
Fair Value of ETC - Summary of changes in quantity of ETC and the respective fair value (Detail)
$ in Thousands
 3 Months Ended 12 Months Ended
Mar. 31, 2026
USD ($)
ETC
Mar. 31, 2025
USD ($)
ETC
Dec. 31, 2025
USD ($)
ETC
Fair Value Disclosures [Abstract]      
Investment Owned, Balance | ETC 10,985,516.92607291 11,263,626.2550315 11,263,626.2550315
ETC contributed | ETC 0   0
ETC distributed for Sponsor's Fee, related party | ETC (67,512.95041201) (69,222.1081569)  
Net change in unrealized appreciation/depreciation on investment in ETC | ETC 0 0  
Net realized gain on investment in ETC | ETC 0 0  
Investment Owned, Balance | ETC 10,918,003.9756609 11,194,404.1468746 10,985,516.92607291
Investment Owned, Fair Value | $ $ 126,004 $ 283,055 $ 283,055
ETC contributed | $ 0   0
ETC distributed for Sponsor's Fee, related party | $ (660) (1,511)  
Net change in unrealized appreciation/depreciation on investment in ETC | $ (36,076) (94,019)  
Net realized gain on investment in ETC | $ 150 989  
Investment Owned, Fair Value | $ $ 89,418 $ 188,514 $ 126,004