XML 49 R38.htm IDEA: XBRL DOCUMENT v3.21.2
Supplemental balance sheet and cash flow information (trade accounts receivable, allowances for uncollectible accounts) (Details) - USD ($)
$ in Thousands
9 Months Ended
Sep. 30, 2021
Sep. 30, 2020
Accounts receivable, allowances for uncollectible accounts [Roll Forward]    
Balance, beginning of year $ 6,428 $ 4,985
Bad debt (benefit) expense (412) 4,174
Write-offs and other (2,555) (2,671)
Balance, end of period $ 3,461 $ 6,488