REPORTING SEGMENTS AND RELATED INFORMATION - Revenue Components of Mineral Resources Segment (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Revenue from External Customer [Line Items]
Total expenses	$ 15,808	$ 12,108
Operating results	5,212	(1,054)
Operating Segments
Revenue from External Customer [Line Items]
Total revenues	21,020	11,054
Mineral resources | Operating Segments
Revenue from External Customer [Line Items]
Total revenues	11,968	7,176
Total expenses	7,157	5,047
Operating results	$ 4,811	$ 2,129