Transfers of Financial Assets Servicing Assets at Amortized Cost Roll Forward (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Servicing Asset at Amortized Cost, Balance [Roll Forward]
Beginning balance	$ 20,698	$ 19,379	$ 20,983
Additions	11,312	8,027	4,581
Amortization	(7,554)	(6,699)	(6,318)
Valuation recovery (provision)	10	(9)	133
Ending balance	24,466	20,698	19,379
Valuation allowance	$ 22	$ 32	$ 23