Gold and Silver Rounds/Bullion - Bullion Holdings (Details) $ in Thousands	Mar. 31, 2020 USD ($) oz $ / oz	Dec. 31, 2019 USD ($) oz $ / oz
Schedule of Investments [Line Items]
Total carrying value	$ 4,111	$ 4,265
Gold
Schedule of Investments [Line Items]
Ounces | oz	1,866	1,866
Carrying value per ounce | $ / oz	1,609	1,515
Total carrying value	$ 3,002	$ 2,827
Silver
Schedule of Investments [Line Items]
Ounces | oz	79,605	79,662
Carrying value per ounce | $ / oz	13.93	18.05
Total carrying value	$ 1,109	$ 1,438