Borrowings (Repurchase Agreements and Fed Funds) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Debt Disclosure [Abstract]
Balance outstanding at end of year	$ 51,052	$ 17,000
Average balance outstanding	38,191	16,270
Maximum outstanding at any month-end	$ 62,651	$ 57,009
Average interest rate during the year	0.10%	0.10%
Average interest rate at end of year	0.10%	0.68%