Commitments And Contingencies (Details) - Mt Todd, Australia $ in Thousands	12 Months Ended
	Dec. 31, 2018 AUD ($)
Loss Contingencies [Line Items]
Percentage of ownership in project	100.00%
Scenario, Plan
Loss Contingencies [Line Items]
Percentage of ownership in project	90.00%
Scenario, Plan | Jawoyn Association Aboriginal Corporation
Loss Contingencies [Line Items]
Percentage of ownership in project	10.00%
Percentage of royalty on gold	1.00%
Percentage of royalty on other metals	1.00%
Minimum payment per year	$ 50