INVESTMENT IN MINERA SANTA CRUZ S.A. ("MSC") - SAN JOSE MINE - Argentinian Tax Reform (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent			35.00%	34.00%	34.00%
Recovery of income taxes			$ (15,369)	$ (3,749)	$ (24,560)
Argentina
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent			35.00%
Recovery of income taxes			$ 5,600
Forecast
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent		21.00%
Forecast | Argentina
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent	25.00%