OPERATING SEGMENT REPORTING - Geographic information (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Operating Segment Reporting
Revenue	$ 117,019	$ 128,175	$ 67,465
Long-lived Assets	539,150	557,565
Investment in MSC	110,183	127,814
Operating Lease, Right-of-Use Asset	1,000
MSC
Operating Segment Reporting
Revenue	263,887	213,096	235,650
Investment in MSC	110,183	127,814	150,064
Bank of Nova Scotia \| Sales \| Customer
Operating Segment Reporting
Revenue	$ 103,600	$ 123,500	$ 65,900
Gold and silver sales, percentage	89.00%	96.00%	94.00%
United States
Operating Segment Reporting
Revenue	$ 43,847
Long-lived Assets	135,854	$ 127,617
Canada
Operating Segment Reporting
Revenue	50,058	62,024	$ 11,620
Long-lived Assets	77,147	84,119
Canada \| MSC
Operating Segment Reporting
Investment in MSC		127,800
Mexico
Operating Segment Reporting
Revenue	23,114	66,151	$ 55,845
Long-lived Assets	23,551	26,524
Argentina
Operating Segment Reporting
Long-lived Assets	302,598	$ 319,305
Argentina \| MSC
Operating Segment Reporting
Investment in MSC	$ 110,200

For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

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