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Exploration License - Additional Information (Detail) - USD ($)
Sep. 30, 2019
Jul. 09, 2019
Accounting Standards Update 2017-01 [Member]    
Business Acquisition [Line Items]    
Percent of ownership acquired 79.90%  
Bismarck [Member]    
Business Acquisition [Line Items]    
Annual Fee Due   $ 14,000
Bismarck [Member] | Accounting Standards Update 2017-01 [Member]    
Business Acquisition [Line Items]    
Percent of ownership acquired   79.90%