Revenues - Disaggregation of revenue (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2021 USD ($) oz	Mar. 31, 2020 USD ($) oz
Disaggregation of Revenue [Line Items]
Revenues | $	$ 19,036	$ 11,146
Ounces Sold | oz
Gold sales
Disaggregation of Revenue [Line Items]
Revenues | $	$ 17,541	$ 10,348
Ounces Sold | oz	9,830	6,560
Silver sales
Disaggregation of Revenue [Line Items]
Revenues | $	$ 1,495	$ 798
Ounces Sold | oz	57,236	49,373