Segment Information - Summary of segment information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Australia segment operating income (expense):
Gain on grant of royalty interest in mineral titles	$ 16,909
Depreciation and amortization	(55)	$ (40)
Corporate administration	(3,663)	(3,504)
Gain on sale of plant and equipment	802
Total operating income (expense), net	10,535	(6,764)
Non-operating income (expense):
Interest income	701	263
Other income (expense)	13	(84)
Total non-operating income	714	179
Net income (loss)	11,249	(6,585)
Long-lived assets	1,471	2,419
Corporate
Australia segment operating income (expense):
Corporate administration	(3,663)	(3,504)
Australia segment
Non-operating income (expense):
Mineral property and capital assets	2,209	51
Long-lived assets	1,402	2,350
Australia segment | Operating segments
Australia segment operating income (expense):
Gain on grant of royalty interest in mineral titles	16,909
Employee Compensation	(1,749)	(1,675)
Drilling	(1,891)
Capitalized Development Drilling	1,865
Project Programs	(506)	(412)
Site Holding	(458)	(307)
Administrative	(388)	(384)
Consulting & Contract Services	(201)	(222)
Power	(130)	(220)
Depreciation and amortization	(55)	(40)
Total operating income (expense), net	$ 13,396	$ (3,260)