Quarterly report pursuant to Section 13 or 15(d)

Allowance for Doubtful Accounts

Allowance for Doubtful Accounts
9 Months Ended
Sep. 30, 2021
Credit Loss [Abstract]  
Allowance for Doubtful Accounts Allowance for Doubtful Accounts
We estimate the lifetime allowance for doubtful, potentially uncollectible, accounts receivable upon their inception based on historical collection experience within the markets in which we operate, customer-specific information such as bankruptcy filings or customer liquidity problems, current conditions, and reasonable and supportable forecasts about the future.
Our allowance for doubtful accounts is presented as a reduction to accounts receivable on our consolidated balance sheet. When all internal efforts have been exhausted to collect the receivable, it is written off and relieved from the reserve.
The details of activity in allowance for doubtful accounts are as follows (in thousands):
Three Months Ended
September 30,
Nine Months Ended
September 30,
2021 2020 2021 2020
Balance, beginning of period $ 6,130  $ 7,539  $ 6,213  $ 7,384 
Additions charged to expense (14) 209  273  1,158 
Write-offs charged against allowance (136) (1,079) (506) (1,873)
Balance, end of period $ 5,980  $ 6,669  $ 5,980  $ 6,669