Loan Sales and Servicing Activities - Geographical Distribution of Loans (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Loan Sales and Servicing Activities
Total loans serviced	$ 509,708,281	$ 426,750,830
California
Loan Sales and Servicing Activities
Total loans serviced	67,317,935	60,591,363
Florida
Loan Sales and Servicing Activities
Total loans serviced	45,222,233	35,360,190
Texas
Loan Sales and Servicing Activities
Total loans serviced	42,064,686	34,591,419
Virginia
Loan Sales and Servicing Activities
Total loans serviced	31,442,370	26,209,701
Maryland
Loan Sales and Servicing Activities
Total loans serviced	23,922,075	19,974,809
All other states
Loan Sales and Servicing Activities
Total loans serviced	$ 299,738,982	$ 250,023,348