Short-term and Other Investments - Other Investments (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Other Investments
Proceeds from Sale and Maturity of Marketable Securities	$ 300
Other investments, at fair value	$ 2,247		$ 3,676
Midas Gold Shares [Member]
Other Investments
Shares owned	6,240,115		6,882,115
Marketable Securities Cumulative Gain (Loss)	$ (2,577)		$ (2,562)
Number Marketable Securities Sold	642,000,000	0
Proceeds from Sale and Maturity of Marketable Securities	$ 300
Marketable Securities, Realized Gain (Loss)	$ (15)
Nusantara Resources
Other Investments
Shares owned	1,333,334		1,333,334