Description of Business and Basis of Presentation - Basis of Presentation (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Assets	$ 6,977,364	$ 7,107,398
Liabilities	2,499,822	$ 2,611,860
Variable Interest Entity, Primary Beneficiary
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Assets	307,100
Liabilities	$ 305,600