PROPERTY, PLANT AND EQUIPMENT AND CONSTRUCTION-IN-PROCESS - Activity in Construction and Development (Details) - USD ($)	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Construction in Progress [Roll Forward]
Balance	$ 814,967,000
Write-off of unsuccessful exploration costs	(3,930,000)	$ (3,733,000)	$ (828,000)
Balance	755,589,000	814,967,000
Projects under exploration and development
Construction in Progress [Roll Forward]
Balance	162,476,000	95,268,000	50,702,000
Cost incurred during the year	36,339,000	70,667,000	44,566,000
Write-off of unsuccessful exploration costs	(1,971,000)	(3,459,000)
Transfer of projects under exploration and development to projects under construction	3,141,000
Balance	193,703,000	162,476,000	95,268,000
Projects under exploration and development | Up-front Bonus Costs
Construction in Progress [Roll Forward]
Balance	5,335,000	5,335,000	5,335,000
Cost incurred during the year	0	0	0
Write-off of unsuccessful exploration costs	(4,000)	0
Transfer of projects under exploration and development to projects under construction	0
Balance	5,331,000	5,335,000	5,335,000
Projects under exploration and development | Exploration and Development Costs
Construction in Progress [Roll Forward]
Balance	156,438,000	89,230,000	44,664,000
Cost incurred during the year	36,339,000	70,667,000	44,566,000
Write-off of unsuccessful exploration costs	(1,967,000)	(3,459,000)
Transfer of projects under exploration and development to projects under construction	3,141,000
Balance	187,669,000	156,438,000	89,230,000
Projects under exploration and development | Interest Capitalized
Construction in Progress [Roll Forward]
Balance	703,000	703,000	703,000
Cost incurred during the year	0	0	0
Write-off of unsuccessful exploration costs	0	0
Transfer of projects under exploration and development to projects under construction	0
Balance	703,000	703,000	703,000
Projects under construction
Construction in Progress [Roll Forward]
Balance	652,491,000	797,930,000	670,781,000
Cost incurred during the year	379,886,000	488,603,000	495,526,000
Write-off of unsuccessful exploration costs	(1,958,000)	(993,000)
Transfer of projects under exploration and development to projects under construction	3,141,000
Transfer of completed projects to property, plant and equipment	(471,674,000)	(633,049,000)	(368,377,000)
Balance	561,886,000	652,491,000	797,930,000
Projects under construction | Up-front Bonus Costs
Construction in Progress [Roll Forward]
Balance	11,156,000	11,156,000	39,156,000
Cost incurred during the year	0	0	0
Write-off of unsuccessful exploration costs	0	0
Transfer of projects under exploration and development to projects under construction	0
Transfer of completed projects to property, plant and equipment	(125,000)	0	(28,000,000)
Balance	11,031,000	11,156,000	11,156,000
Projects under construction | Exploration and Development Costs
Construction in Progress [Roll Forward]
Transfer of projects under exploration and development to projects under construction	3,141,000
Projects under construction | Drilling and Construction Costs
Construction in Progress [Roll Forward]
Balance	618,416,000	761,129,000	611,553,000
Cost incurred during the year	367,674,000	473,422,000	489,953,000
Write-off of unsuccessful exploration costs	(1,958,000)	(993,000)
Transfer of completed projects to property, plant and equipment	(457,500,000)	(615,142,000)	(340,377,000)
Balance	529,773,000	618,416,000	761,129,000
Projects under construction | Interest Capitalized
Construction in Progress [Roll Forward]
Balance	22,919,000	25,645,000	20,072,000
Cost incurred during the year	12,212,000	15,181,000	5,573,000
Write-off of unsuccessful exploration costs	0	0
Transfer of projects under exploration and development to projects under construction	0
Transfer of completed projects to property, plant and equipment	(14,049,000)	(17,907,000)	0
Balance	$ 21,082,000	$ 22,919,000	$ 25,645,000