Guarantees - Changes from credit recourses agreements - subnote (Details) - Loans with recourse - Serviced mortgage loans - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Guarantor Obligations
Repurchased loans	$ 2.0	$ 131.0	$ 17.0	$ 143.0
Loans from FNMA and FHLMC | Bulk loan repurchase
Guarantor Obligations
Repurchased loans		120.0
Credit recourse reserve		$ 5.1