Organization, Summary of Significant Accounting Policies and New Accounting Standards - Derivative Notional Amounts Outstanding (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Derivative [Line Items]
Total	$ 4,157,979	$ 5,876,277
Interest rate swaps
Derivative [Line Items]
Total	3,035,000	1,475,000
Interest rate futures
Derivative [Line Items]
Total	0	3,400,000
Home loan pipeline hedges
Derivative [Line Items]
Total	575,000	371,000
IRLCs
Derivative [Line Items]
Total	$ 547,979	$ 630,277