Quarterly report pursuant to Section 13 or 15(d)

Note 1 - Basis of Presentation (Details Textual)

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Note 1 - Basis of Presentation (Details Textual)
$ in Millions
3 Months Ended 12 Months Ended
Mar. 31, 2021
USD ($)
Dec. 31, 2020
USD ($)
Accounts Receivable, Allowance for Credit Loss, Ending Balance $ 9.1 $ 9.1
Revenue Benchmark [Member] | Customer Concentration Risk [Member] | Three Major Oil and Gas Companies [Member]    
Concentration Risk, Percentage 67.00% 62.00%
Number of Major Customers 3 3
General and Administrative Expense [Member]    
Employee Retention Credit $ 2.1