Variable Interest Entities - Additional Information (Details) - USD ($)	Dec. 31, 2020	Dec. 31, 2019
Variable Interest Entity [Line Items]
Net assets for VIEs for which the Company has determined it is not the primary beneficiary	$ 1,997,140,000	$ 1,628,719,000
Liabilities related to VIEs for which the Company has determined it is not the primary beneficiary	1,071,058,000	822,191,000
Variable Interest Entity, Primary Beneficiary
Variable Interest Entity [Line Items]
Available bank line financing	25,000,000.0
Net assets for VIEs for which the Company has determined it is not the primary beneficiary	156,784,000
Liabilities related to VIEs for which the Company has determined it is not the primary beneficiary	2,593,000
Variable Interest Entity, Not Primary Beneficiary
Variable Interest Entity [Line Items]
Net assets for VIEs for which the Company has determined it is not the primary beneficiary	1,800,000,000	300,000,000
Variable interest entities, exposure to loss	7,800,000
Liabilities related to VIEs for which the Company has determined it is not the primary beneficiary	$ 0	$ 0