OPERATING SEGMENT REPORTING - Geographic information (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2024	Sep. 30, 2024	Jun. 30, 2024	Mar. 31, 2024	Dec. 31, 2023	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Revenues from External Customers and Long-Lived Assets
Non-current Assets	$ 623,431				$ 604,578				$ 623,431	$ 604,578
Revenue	33,523	$ 52,250	$ 47,476	$ 41,228	58,680	$ 38,404	$ 34,395	$ 34,752	174,477	166,231	$ 110,417
Investment in MSC or McEwen Copper	298,947				326,147				298,947	326,147
Minera Santa Cruz S.A.
Revenues from External Customers and Long-Lived Assets
Revenue									310,411	254,926	254,698
Asahi Refining Inc.
Revenues from External Customers and Long-Lived Assets
Revenue									112,298	24,639	57,835
Auramet International LLC ("Auramet")
Revenues from External Customers and Long-Lived Assets
Revenue									56,869	136,911	50,580
Other
Revenues from External Customers and Long-Lived Assets
Revenue									5,310	4,681	2,002
USA
Revenues from External Customers and Long-Lived Assets
Non-current Assets	100,488				71,234				100,488	71,234
Revenue									105,147	83,409	47,926
Canada
Revenues from External Customers and Long-Lived Assets
Non-current Assets	89,822				83,674				89,822	83,674
Revenue									67,808	81,295	60,848
Mexico
Revenues from External Customers and Long-Lived Assets
Non-current Assets	32,320				30,304				32,320	30,304
Revenue									1,522	1,527	$ 1,643
Argentina
Revenues from External Customers and Long-Lived Assets
Non-current Assets	400,801				419,366				400,801	419,366
Argentina | Minera Santa Cruz S.A.
Revenues from External Customers and Long-Lived Assets
Investment in MSC or McEwen Copper	101,900				93,200				101,900	93,200
Argentina | McEwen Copper
Revenues from External Customers and Long-Lived Assets
Investment in MSC or McEwen Copper	$ 298,900				$ 326,100				$ 298,900	$ 326,100