| Segment Reporting [Table Text Block] |
| | | Reportable Segments | | | | | | | | | | | | | |
| (In thousands) | | Mineral Rights | | | Soda Ash | | | Total Reportable Segments | | | Corporate and Financing | | | Total | |
| For the Three Months Ended June 30, 2026 | | | | | | | | | | | | | | | | | | | | |
| Revenues | | $ | 52,970 | | | $ | — | | | $ | 52,970 | | | $ | — | | | $ | 52,970 | |
| Equity in loss of Sisecam Wyoming | | | — | | | | (4,905 | ) | | | (4,905 | ) | | | — | | | | (4,905 | ) |
| Gain on asset sales and disposals | | | 45 | | | | — | | | | 45 | | | | — | | | | 45 | |
| Total revenues and other income | | $ | 53,015 | | | $ | (4,905 | ) | | $ | 48,110 | | | $ | — | | | $ | 48,110 | |
| Less: | | | | | | | | | | | | | | | | | | | | |
| Compensation (salaries, benefits and bonus) | | $ | 1,808 | | | $ | — | | | $ | 1,808 | | | $ | 1,988 | | | $ | 3,796 | |
| Property taxes | | | 1,876 | | | | — | | | | 1,876 | | | | — | | | | 1,876 | |
| Depreciation, depletion and amortization | | | 11,126 | | | | — | | | | 11,126 | | | | 5 | | | | 11,131 | |
| Other items (1) | | | 1,968 | | | | 79 | | | | 2,047 | | | | 4,084 | | | | 6,131 | |
| Net income (loss) | | $ | 36,237 | | | $ | (4,984 | ) | | $ | 31,253 | | | $ | (6,077 | ) | | $ | 25,176 | |
| | | | | | | | | | | | | | | | | | | | | |
| For the Three Months Ended June 30, 2025 | | | | | | | | | | | | | | | | | | | | |
| Revenues | | $ | 46,846 | | | $ | — | | | $ | 46,846 | | | $ | — | | | $ | 46,846 | |
| Equity in earnings of Sisecam Wyoming | | | — | | | | 2,526 | | | | 2,526 | | | | — | | | | 2,526 | |
| Gain on asset sales and disposals | | | 729 | | | | — | | | | 729 | | | | — | | | | 729 | |
| Total revenues and other income | | $ | 47,575 | | | $ | 2,526 | | | $ | 50,101 | | | $ | — | | | $ | 50,101 | |
| Less: | | | | | | | | | | | | | | | | | | | | |
| Compensation (salaries, benefits and bonus) | | $ | 1,683 | | | $ | — | | | $ | 1,683 | | | $ | 1,847 | | | $ | 3,530 | |
| Property taxes | | | 1,767 | | | | — | | | | 1,767 | | | | — | | | | 1,767 | |
| Depreciation, depletion and amortization | | | 3,748 | | | | — | | | | 3,748 | | | | 6 | | | | 3,754 | |
| Other items (1) | | | 686 | | | | 24 | | | | 710 | | | | 6,129 | | | | 6,839 | |
| Net income (loss) | | $ | 39,691 | | | $ | 2,502 | | | $ | 42,193 | | | $ | (7,982 | ) | | $ | 34,211 | |
| | | | | | | | | | | | | | | | | | | | | |
| For the Six Months Ended June 30, 2026 | | | | | | | | | | | | | | | | | | | | |
| Revenues | | $ | 100,152 | | | $ | — | | | $ | 100,152 | | | $ | — | | | $ | 100,152 | |
| Equity in loss of Sisecam Wyoming | | | — | | | | (12,733 | ) | | | (12,733 | ) | | | — | | | | (12,733 | ) |
| Gain on asset sales and disposals | | | 44 | | | | — | | | | 44 | | | | — | | | | 44 | |
| Total revenues and other income | | $ | 100,196 | | | $ | (12,733 | ) | | $ | 87,463 | | | $ | — | | | $ | 87,463 | |
| Less: | | | | | | | | | | | | | | | | | | | | |
| Compensation (salaries, benefits and bonus) | | $ | 3,605 | | | $ | — | | | $ | 3,605 | | | $ | 4,052 | | | $ | 7,657 | |
| Property taxes | | | 3,755 | | | | — | | | | 3,755 | | | | — | | | | 3,755 | |
| Depreciation, depletion and amortization | | | 18,736 | | | | — | | | | 18,736 | | | | 9 | | | | 18,745 | |
| Other items (1) | | | 4,333 | | | | 151 | | | | 4,484 | | | | 8,027 | | | | 12,511 | |
| Net income (loss) | | $ | 69,767 | | | $ | (12,884 | ) | | $ | 56,883 | | | $ | (12,088 | ) | | $ | 44,795 | |
| As of June 30, 2026 | | | | | | | | | | | | | | | | | | | | |
| Total assets | | $ | 475,312 | | | $ | 277,475 | | | $ | 752,787 | | | $ | 4,748 | | | $ | 757,535 | |
| | | | | | | | | | | | | | | | | | | | | |
| For the Six Months Ended June 30, 2025 | | | | | | | | | | | | | | | | | | | | |
| Revenues | | $ | 102,527 | | | $ | — | | | $ | 102,527 | | | $ | — | | | $ | 102,527 | |
| Equity in earnings of Sisecam Wyoming | | | — | | | | 7,136 | | | | 7,136 | | | | — | | | | 7,136 | |
| Gain on asset sales and disposals | | | 976 | | | | — | | | | 976 | | | | — | | | | 976 | |
| Total revenues and other income | | $ | 103,503 | | | $ | 7,136 | | | $ | 110,639 | | | $ | — | | | $ | 110,639 | |
| Less: | | | | | | | | | | | — | | | | | | | | — | |
| Compensation (salaries, benefits and bonus) | | $ | 3,621 | | | $ | — | | | $ | 3,621 | | | $ | 3,956 | | | $ | 7,577 | |
| Property taxes | | | 3,559 | | | | — | | | | 3,559 | | | | — | | | | 3,559 | |
| Depreciation, depletion and amortization | | | 7,733 | | | | — | | | | 7,733 | | | | 10 | | | | 7,743 | |
| Asset impairments | | | 20 | | | | — | | | | 20 | | | | — | | | | 20 | |
| Other items (1) | | | 3,671 | | | | 84 | | | | 3,755 | | | | 13,521 | | | | 17,276 | |
| Net income (loss) | | $ | 84,899 | | | $ | 7,052 | | | $ | 91,951 | | | $ | (17,487 | ) | | $ | 74,464 | |
| As of December 31, 2025 | | | | | | | | | | | | | | | | | | | | |
| Total assets | | $ | 492,672 | | | $ | 250,244 | | | $ | 742,916 | | | $ | 5,449 | | | $ | 748,365 | |
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