BUSINESS SEGMENTS - Reconciling Information Between Reportable Segments and Consolidated Totals (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Segment Reporting [Abstract]
Segment gross profit (loss)	$ 56,895	$ 61,386	$ 129,822	$ 140,196
Operating expenses:
Research and development expenses	1,439	1,730	3,981	3,294
Selling and marketing expenses	4,370	4,167	8,542	9,293
General and administrative expenses	19,786	18,026	37,695	37,563
Other operating income	(4,269)	0	(7,394)	0
Impairment of long-lived assets	0	957	0	957
Write-off of unsuccessful exploration and storage activities	251	1,379	767	1,379
Operating income	35,318	35,127	86,231	87,710
Interest income	1,929	2,604	3,242	4,443
Interest expense, net	(36,682)	(33,716)	(71,155)	(64,684)
Derivatives and foreign currency transaction gains (losses)	5,068	(332)	7,128	(1,914)
Income attributable to sale of tax benefits	16,251	15,798	33,822	33,274
Other non-operating income, net	76	74	298	100
Income from operations before income tax and equity in earnings of investees	$ 21,960	$ 19,555	$ 59,566	$ 58,929