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Summary of Significant Accounting Policies - Composition of the Allowance for Credit Losses (Details) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Accounts Receivable, Allowance for Credit Loss [Roll Forward]      
Balance at beginning of year $ 9,398 $ 5,839 $ 4,465
Charges to bad debt expense 3,656 11,249 7,169
Direct write-offs charged against the allowance (1,575) (7,690) (5,795)
Balance at end of year 16,546 9,398 $ 5,839
Cumulative Effect, Period of Adoption, Adjustment      
Accounts Receivable, Allowance for Credit Loss [Roll Forward]      
Balance at beginning of year $ 5,067    
Balance at end of year   $ 5,067