Note 6 - Segment Information - Information By Segment (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Revenues	$ 57,252	$ 64,277	$ 128,051	$ 144,146
Equity in earnings of Sisecam Wyoming	3,645	26,978	9,095	46,232
Gain on asset sales and disposals	4,643	5	4,808	101
Operating and maintenance expenses	5,872	7,930	11,605	15,093
Depreciation, depletion and amortization	3,324	3,792	7,978	7,875
General and administrative expenses	5,931	5,643	12,258	11,488
Interest expense, net	4,349	3,492	7,836	6,345
Net income (loss)	46,064	70,334	102,277	149,609
Asset impairments	0	69	0	69
Segment Reporting, Reconciling Item, Corporate Nonsegment [Member]
Revenues	0	0	0	0
Equity in earnings of Sisecam Wyoming	0	0	0	0
Gain on asset sales and disposals	0	0	0	0
Operating and maintenance expenses	0	0	0	0
Depreciation, depletion and amortization	4	5	9	9
General and administrative expenses	5,931	5,643	12,258	11,488
Interest expense, net	4,349	3,492	7,836	6,345
Net income (loss)	(10,284)	(9,140)	(20,103)	(17,842)
Asset impairments		0		0
Mineral Rights Segment [Member] | Operating Segments [Member]
Revenues	57,252	64,277	128,051	144,146
Equity in earnings of Sisecam Wyoming	0	0	0	0
Gain on asset sales and disposals	4,643	5	4,808	101
Operating and maintenance expenses	5,846	7,916	11,517	14,921
Depreciation, depletion and amortization	3,320	3,787	7,969	7,866
General and administrative expenses	0	0	0	0
Interest expense, net	0	0	0	0
Net income (loss)	52,729	52,510	113,373	121,391
Asset impairments		69		69
Soda Ash Segment [Member] | Operating Segments [Member]
Revenues	0	0	0	0
Equity in earnings of Sisecam Wyoming	3,645	26,978	9,095	46,232
Gain on asset sales and disposals	0	0	0	0
Operating and maintenance expenses	26	14	88	172
Depreciation, depletion and amortization	0	0	0	0
General and administrative expenses	0	0	0	0
Interest expense, net	0	0	0	0
Net income (loss)	$ 3,619	26,964	$ 9,007	46,060
Asset impairments		$ 0		$ 0