XML 81 R54.htm IDEA: XBRL DOCUMENT v3.20.4
Accounts Receivable - Balance and Activity in Allowance for Doubtful Accounts (Details) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Allowance for Doubtful Accounts Receivable [Roll Forward]    
Beginning balance $ 1,117 $ 1,295
Additions charged to costs and expenses 3,239 6
Deductions 0 (184)
Ending balance 4,356 1,117
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Additions charged to costs and expenses 3,239 $ 6
Governmental and Other Regulatory Items    
Allowance for Doubtful Accounts Receivable [Roll Forward]    
Additions charged to costs and expenses 2,500  
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Additions charged to costs and expenses $ 2,500