Loan Servicing (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Transfers and Servicing of Financial Assets [Abstract]
Serviced sold mortgage loans	$ 1,370,000	$ 1,330,000	$ 1,370
Serviced sold mortgage loans with recourse	2,800	3,600	$ 3,000
Servicing fees included in other service income	900	$ 900
Mortgage Loans Sold with Recourse, Reserve	$ 43