Mineral Properties - Awak Mas (Details) $ in Thousands			3 Months Ended	6 Months Ended
	May 05, 2020 USD ($)	Nov. 01, 2019 USD ($) oz	Jun. 30, 2020 USD ($)	Jun. 30, 2020 USD ($)	May 04, 2020 USD ($)	Dec. 31, 2019 USD ($)
Property, Plant and Equipment [Line Items]
Gain (Loss) On Disposal Of Mineral Property Interests, Net			$ 2,568	$ 2,568
Disposal Group, Deferred Gain on Disposal						$ 2,960
PT Masmindo Dwi Area | Awak Mas
Property, Plant and Equipment [Line Items]
NSR Cancellation Proceeds	$ 2,400
Gain (Loss) On Disposal Of Mineral Property Interests, Net	$ 2,568
Disposal Group, Deferred Gain on Disposal			$ 68	$ 68	$ 168
PT Masmindo Dwi Area | Awak Mas | First 1,250,000 Ounces Produced
Property, Plant and Equipment [Line Items]
NSR Royalty Cancellation, Percentage		1.00%
Remaining NSR Royalty Cancellation, Percentage		1.00%
Net Smelter Return Royalty Agreement Benchmark | oz		1,250,000
NSR Royalty Cancelled Percentage	1.00%
PT Masmindo Dwi Area | Awak Mas | Next 1,250,000 Ounces Produced
Property, Plant and Equipment [Line Items]
NSR Royalty Cancellation, Percentage		1.25%
Remaining NSR Royalty Cancellation, Percentage		1.25%
Net Smelter Return Royalty Agreement Benchmark | oz		1,250,000
NSR Royalty Cancelled Percentage	1.25%
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-04-20 | PT Masmindo Dwi Area | Awak Mas | First 1,250,000 Ounces Produced
Property, Plant and Equipment [Line Items]
NSR Cancellation Receivable		$ 2,400
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-04-30 | PT Masmindo Dwi Area | Awak Mas
Property, Plant and Equipment [Line Items]
NSR Cancellation Proceeds		$ 2,500