INVESTMENT IN MINERA SANTA CRUZ S.A. ("MSC") - SAN JOSE MINE - Summary of Operating Results from MSC (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
INVESTMENT IN MINERA SANTA CRUZ S.A. ("MSC") - SAN JOSE MINE
Revenue from gold and silver sales	$ 23,740	$ 31,400
Depreciation and depletion	(5,137)	(6,698)
Gross Profit	(4,986)	(3,685)
Net income (loss) before tax	(14,481)	(100,285)
Net income (loss)	(12,466)	(99,191)
Income tax recovery	2,015	1,094
Loss from investment in MSC, net of amortization	$ (574)	(2,676)
Subsidiary (as a percent)	100.00%
Ownership interest (as a percent)	49.00%
MSC
INVESTMENT IN MINERA SANTA CRUZ S.A. ("MSC") - SAN JOSE MINE
Revenue from gold and silver sales	$ 53,303	37,390
Production costs applicable to sales	(36,367)	(28,316)
Depreciation and depletion	(6,953)	(7,327)
Gross Profit	9,983	1,747
Exploration	(2,236)	(2,866)
Other expenses	(5,536)	(2,217)
Net income (loss) before tax	2,211	(3,336)
Current and deferred tax expense	(1,629)	49
Net income (loss)	582	(3,287)
Net income (loss)	285		$ 2,745
Amortization of fair value increments	(1,071)		(5,390)
Income tax recovery	212		$ 1,128
Loss from investment in MSC, net of amortization	(574)	(2,676)
MSC | Equity Method Investment
INVESTMENT IN MINERA SANTA CRUZ S.A. ("MSC") - SAN JOSE MINE
Net income (loss)	285	(1,611)
Amortization of fair value increments	(1,071)	(1,385)
Income tax recovery	$ 212	$ 320
Ownership interest (as a percent)	49.00%