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Basis of Presentation - VIE - Additional Information (Details) - USD ($)
Sep. 30, 2021
Dec. 31, 2020
Variable Interest Entity    
Payroll tax withholdings $ 12,961,000  
Primary Beneficiary    
Variable Interest Entity    
Liabilities of the deferred compensation plan 7,087,000 $ 7,961,000
Assets held in the related rabbi trust $ 11,542,000 $ 16,323,000