Variable Interest Entities - Additional Information (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Variable Interest Entity [Line Items]
Assets of the consolidated variable interest entities	$ 644,246	$ 582,426
Liabilities of the consolidated variable interest entities	375,974	324,146
Variable Interest Entity, Primary Beneficiary
Variable Interest Entity [Line Items]
Assets of the consolidated variable interest entities	418,300	361,700
Liabilities of the consolidated variable interest entities	$ 325,900	$ 287,100