| Activity in Silver Bullion [Table Text Block] |
| Three Months Ended June 30, 2021 | | Ounces | | | Cost | | | Fair Value | | | Realized
Gain (Loss) | |
| Beginning balance | | | 575,124,212 | | | $ | 11,937,644,776 | | | $ | 13,802,981,086 | | | $ | — | |
| Silver bullion contributed | | | 28,106,701 | | | | 765,794,167 | | | | 765,794,167 | | | | — | |
| Silver bullion distributed | | | (44,335,250 | ) | | | (928,983,617 | ) | | | (1,177,999,610 | ) | | | 249,015,993 | |
| Silver bullion sold to pay expenses | | | (722,380 | ) | | | (15,051,815 | ) | | | (19,036,249 | ) | | | 3,984,434 | |
| Net realized gain | | | — | | | | — | | | | 253,000,427 | | | | — | |
| Net change in unrealized appreciation/depreciation | | | — | | | | — | | | | 756,594,817 | | | | — | |
| Ending balance | | | 558,173,283 | | | $ | 11,759,403,511 | | | $ | 14,381,334,638 | | | $ | 253,000,427 | |
| Three Months Ended June 30, 2020 | | Ounces | | | Cost | | | Fair Value | | | Realized
Gain (Loss) | |
| Beginning balance | | | 395,368,466 | | | $ | 6,681,432,888 | | | $ | 5,507,482,733 | | | $ | — | |
| Silver bullion contributed | | | 118,708,634 | | | | 1,962,530,775 | | | | 1,962,530,775 | | | | — | |
| Silver bullion distributed | | | (15,569,065 | ) | | | (261,348,495 | ) | | | (250,788,865 | ) | | | (10,559,630 | ) |
| Silver bullion sold to pay expenses | | | (500,537 | ) | | | (8,415,355 | ) | | | (7,832,116 | ) | | | (583,239 | ) |
| Net realized loss | | | — | | | | — | | | | (11,142,869 | ) | | | — | |
| Net change in unrealized appreciation/depreciation | | | — | | | | — | | | | 1,686,694,147 | | | | — | |
| Ending balance | | | 498,007,498 | | | $ | 8,374,199,813 | | | $ | 8,886,943,805 | | | $ | (11,142,869 | ) |
| Six Months Ended June 30, 2021 | | Ounces | | | Cost | | | Fair Value | | | Realized
Gain (Loss) | |
| Beginning balance | | | 558,715,882 | | | $ | 10,472,474,303 | | | $ | 14,797,590,146 | | | $ | — | |
| Silver bullion contributed | | | 192,263,810 | | | | 5,234,465,003 | | | | 5,234,465,003 | | | | — | |
| Silver bullion distributed | | | (191,415,186 | ) | | | (3,919,057,880 | ) | | | (5,056,623,118 | ) | | | 1,137,565,238 | |
| Silver bullion sold to pay expenses | | | (1,391,223 | ) | | | (28,477,915 | ) | | | (37,671,676 | ) | | | 9,193,761 | |
| Net realized gain | | | — | | | | — | | | | 1,146,758,999 | | | | — | |
| Net change in unrealized appreciation/depreciation | | | — | | | | — | | | | (1,703,184,716 | ) | | | — | |
| Ending balance | | | 558,173,283 | | | $ | 11,759,403,511 | | | $ | 14,381,334,638 | | | $ | 1,146,758,999 | |
| Six Months Ended June 30, 2020 | | Ounces | | | Cost | | | Fair Value | | | Realized Gain (Loss) | |
| Beginning balance | | | 362,616,711 | | | $ | 6,294,157,046 | | | $ | 6,543,418,555 | | | $ | — | |
| Silver bullion contributed | | | 180,427,906 | | | | 2,852,348,213 | | | | 2,852,348,213 | | | | — | |
| Silver bullion distributed | | | (44,081,945 | ) | | | (755,993,432 | ) | | | (735,788,453 | ) | | | (20,204,979 | ) |
| Silver bullion sold to pay expenses | | | (955,174 | ) | | | (16,312,014 | ) | | | (15,803,415 | ) | | | (508,599 | ) |
| Net realized loss | | | — | | | | — | | | | (20,713,578 | ) | | | — | |
| Net change in unrealized appreciation/depreciation | | | — | | | | — | | | | 263,482,483 | | | | — | |
| Ending balance | | | 498,007,498 | | | $ | 8,374,199,813 | | | $ | 8,886,943,805 | | | $ | (20,713,578 | ) |
|