Transfers of Financial Assets Servicing Assets at Amortized Cost Roll Forward (Details) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Servicing Asset at Amortized Cost, Balance [Roll Forward]
Beginning Balance	$ 24,708	$ 21,946	$ 24,466	$ 20,698
Additions	2,576	3,338	7,063	8,198
Amortization	(2,144)	(1,900)	(6,389)	(5,512)
Ending Balance	$ 25,140	$ 23,384	$ 25,140	$ 23,384