Guarantees - Credit recourse - Additional Information (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021	Jun. 30, 2022	Dec. 31, 2021	Jun. 30, 2021	Dec. 31, 2020
Guarantee on loans sold or serviced with credit recourse
Guarantor Obligations
Valuation allowances and reserves balance	$ 7,193,000	$ 12,651,000	$ 7,193,000	$ 12,651,000	$ 9,095,000	$ 11,800,000	$ 15,662,000	$ 22,484,000
Serviced mortgage loans
Guarantor Obligations
Loans serviced	11,400,000,000		11,400,000,000			12,100,000,000
Loans with recourse
Guarantor Obligations
Loans serviced	700,000,000		700,000,000			$ 700,000,000
Loans with recourse | Serviced mortgage loans
Guarantor Obligations
Repurchased loans	$ 1,000,000	$ 2,000,000	6,000,000	17,000,000
Securitization | Guarantee on loans sold or serviced with representation and warranties
Guarantor Obligations
Repurchased loans			$ 1,000,000	$ 0