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Summary of Significant Accounting Policies - Narrative (Details) - USD ($)
$ in Thousands, shares in Millions
3 Months Ended 6 Months Ended
Jun. 30, 2021
Jun. 30, 2020
Jun. 30, 2021
Jun. 30, 2020
Dec. 31, 2020
Accounting Policies [Abstract]          
Allowance for doubtful accounts $ 3,370   $ 3,370   $ 3,443
Unearned revenue 22,893   22,893   $ 14,101
Prior year unearned revenue recognized in period     7,500    
Share-based compensation costs $ 6,400 $ 3,000 $ 14,700 $ 7,200  
Antidilutive securities excluded from computation of Earnings Per Share, amount     2.5 2.3