Inventory and Ore on Leach Pads (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Inventory Disclosure [Abstract]
Inventory, Finished Goods, Net of Reserves	$ 2,100	$ 2,909
Other Inventory, Net of Reserves	16,573	14,788
Inventory, Supplies, Net of Reserves	34,918	33,513
Inventory	53,591	51,210
Ore on Leach Pad, Current	78,689	74,866
Ore on leach pads, noncurrent	87,723	81,963
Inventory, Ore Stockpiles on Leach Pads, Gross	166,412	156,829
Inventory and Ore on Leach Pads	230,762	213,703
Long-Term Inventory Stockpile	$ 10,759	$ 5,664