Guarantees - Changes from credit recourses agreements (Details) - Financial Guarantee - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Guarantor Obligations
Balance as of beginning of period	$ 34,862	$ 56,230
Impact of adopting CECL	(3,831)	0
Provision (reversal) for recourse liability	4,364	(311)
Net charge-offs / terminations	(3,676)	(3,908)
Balance as of end of period	$ 31,719	$ 52,011