Guarantees - Changes from credit recourses agreements (Details) - Financial Guarantee - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Guarantor Obligations
Balance as of beginning of period	$ 31,719	$ 52,011	$ 34,862	$ 56,230
Impact of adopting CECL	0	0	(3,831)	0
Provision for recourse liability	1,050	1,267	5,414	956
Net charge-offs	(1,464)	(5,178)	(5,140)	(9,086)
Balance as of end of period	$ 31,305	$ 48,100	$ 31,305	$ 48,100