Guarantees - Changes from credit recourses agreements (Details) - Guarantee on loans sold or serviced with credit recourse - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Guarantor Obligations
Balance as of beginning of period	$ 15,662	$ 31,305	$ 22,484	$ 34,862
Impact of adopting CECL	0	0	0	(3,831)
Provision (reversal) for recourse liability	(1,959)	(4,058)	(2,710)	1,356
Net charge-offs	(1,052)	(362)	(7,123)	(5,502)
Balance as of end of period	$ 12,651	$ 26,885	$ 12,651	$ 26,885