Securities (Held to Maturity Securities Losses) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Fair Value
Less than 12 months	$ 8,512	$ 31,479
12 months or longer	8,989	2,017
Total	17,501	33,496
Unrealized Losses
Less than 12 months	(49)	(884)
12 months or longer	(467)	(261)
Total	(516)	(1,145)
Obligations of states and political subdivisions
Fair Value
Less than 12 months	8,512	31,479
12 months or longer	8,989	2,017
Total	17,501	33,496
Unrealized Losses
Less than 12 months	(49)	(884)
12 months or longer	(467)	(261)
Total	$ (516)	$ (1,145)