MINERAL PROPERTY INTERESTS AND PLANT AND EQUIPMENT- Mineral Properties (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Aug. 25, 2017
Mineral Property Interests
Mineral property interests	$ 311,220	$ 309,145
Amortization of mineral property interests and asset retirement obligations	25,543	16,425	$ 6,576
Black Fox
Mineral Property Interests
Mineral property interests	14,627	16,365
Lexam VG Gold
Mineral Property Interests
Mineral property interests	41,595	41,595
Los Azules Copper Project
Mineral Property Interests
Mineral property interests	191,490	191,490
Gold Bar Project
Mineral Property Interests
Mineral property interests	48,492	44,131
El Gallo Project
Mineral Property Interests
Mineral property interests	3,591	4,139
Fenix Project Properties
Mineral Property Interests
Mineral property interests	5,807	5,807
Battle Mountain Complex
Mineral Property Interests
Mineral property interests	785	785
Tonkin Properties
Mineral Property Interests
Mineral property interests	$ 4,833	$ 4,833
Black Fox
Mineral Property Interests
Mineral property interests				$ 8,954