Significant Accounting Policies - Summary of Trust's Assets Accounted at Fair Value (Details) - USD ($) $ in Thousands	Mar. 31, 2026	Dec. 31, 2025	Dec. 31, 2024
Assets
Investment in ether, at fair value	$ 219,266	$ 343,746	$ 404,529
Level 1
Assets
Investment in ether, at fair value	219,266	343,746
Level 2
Assets
Investment in ether, at fair value	0	0
Level 3
Assets
Investment in ether, at fair value	$ 0	$ 0