Fair Value of Financial Instruments (Servicing Assets) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Default rate assumption, default rate increase of 25%	25.00%
Default rate assumption, default rate increase of 50%	50.00%
Cost to service assumption, cost to service increase by 25%	25.00%
Cost to service assumption, cost to service increase by 50%	50.00%
Default rate increase of 25%	$ (40)	$ (98)
Default rate increase of 50%	(76)	(188)
Cost to service increase by 25%	(63)	(60)
Cost to service increase by 50%	$ (126)	$ (120)