XML 59 R37.htm IDEA: XBRL DOCUMENT v3.21.1
Note 1 - Nature of Operations (Details Textual)
3 Months Ended 12 Months Ended
Sep. 30, 2020
Dec. 31, 2020
Juanicipio Joint Venture [member]    
Statement Line Items [Line Items]    
Proportion of ownership interest in joint venture 44.00% 44.00%