Mortgage Banking - Schedule of Mortgage Loans Sold and Serviced for Others (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Mortgage Loans On Real Estate [Line Items]
Total mortgage loans sold and serviced for others	$ 7,876,527	$ 7,657,090
Federal National Mortgage Association [Member]
Mortgage Loans On Real Estate [Line Items]
Total mortgage loans sold and serviced for others	4,676,745	4,629,670
Government National Mortgage Association [Member]
Mortgage Loans On Real Estate [Line Items]
Total mortgage loans sold and serviced for others	3,146,324	2,960,760
Federal Home Loan Mortgage Corporation [Member]
Mortgage Loans On Real Estate [Line Items]
Total mortgage loans sold and serviced for others	39,275	50,459
Other [Member]
Mortgage Loans On Real Estate [Line Items]
Total mortgage loans sold and serviced for others	$ 14,183	$ 16,201