Servicing Rights (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Transfers and Servicing [Abstract]
Serviced unpaid principal balance	$ 181.0	$ 222.0
Unpaid principal balance for loans sold during period	72.5	368.3	$ 600.0
Servicing revenue	$ 1.1	$ 1.2	$ 3.5