Inventory and Ore on Leach Pads (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Inventory Disclosure [Abstract]
Inventory, Finished Goods, Net of Reserves	$ 1,854	$ 6,557
Other Inventory, Net of Reserves	13,237	14,040
Inventory, Supplies, Net of Reserves	31,887	35,289
Inventory	46,978	55,886
Ore on Leach Pad, Current	72,326	66,192
Ore on leach pads, noncurrent	87,420	71,539
Inventory, Ore Stockpiles on Leach Pads, Gross	159,746	137,731
Inventory and Ore on Leach Pads	210,415	193,617
Long-Term Inventory Stockpile	$ 3,691	$ 0