Revenues - Disaggregation of revenue (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021 USD ($) oz	Jun. 30, 2020 USD ($) oz	Jun. 30, 2021 USD ($) oz	Jun. 30, 2020 USD ($) oz
Disaggregation of Revenue [Line Items]
Revenues	$ 36,001	$ 7,636	$ 55,037	$ 18,760
Gold sales
Disaggregation of Revenue [Line Items]
Revenues	$ 30,900	$ 7,284	$ 48,441	$ 17,612
Ounces Sold | oz	17,060	4,237	26,890	10,797
Silver sales
Disaggregation of Revenue [Line Items]
Revenues	$ 5,101	$ 352	$ 6,596	$ 1,148
Ounces Sold | oz	189,766	21,331	247,002	70,703