Segment Reporting (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2020 USD ($) segment	Mar. 31, 2019 USD ($)	Dec. 31, 2019 USD ($)
Number of reportable segments | segment	2
Total sales, net	$ 28,005	$ 26,578
Exploration expense	4,942	3,486
Net income (loss)	(3,121)	882
Capital expenditures	6,414	11,881
Change in capital expenditures in accounts payable	(950)	2,303
Non - cash additions	435	792
Capital expenditures on a cash basis	6,929	8,786
Assets	196,073		$ 193,012
Mexico
Total sales, net	22,148	26,578
Net income (loss)	(952)	3,396
Capital expenditures	1,979	4,682
Assets	89,677		98,718
Nevada
Total sales, net	5,857
Net income (loss)	(793)	(419)
Capital expenditures	4,398	7,199
Assets	85,947		84,669
Corporate and Other
Net income (loss)	(1,376)	(2,095)
Capital expenditures	37
Assets	20,449		$ 9,625
Exploration expenses
Exploration expense	1,155	1,450
Exploration expenses | Mexico
Exploration expense	968	1,068
Exploration expenses | Nevada
Exploration expense	177	383
Exploration expenses | Corporate and Other
Exploration expense	$ 10	$ (1)