Loans (Summary of TDRs with a Payment Default During the Period) (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2017 USD ($) loan	Dec. 31, 2016 USD ($) loan	Dec. 31, 2015 USD ($) loan
Troubled debt restructurings on financing receivables with defaults payment
Number of loans (in loan) | loan	22	16	9
Principal balance at year end | $	$ 2,051	$ 1,980	$ 2,287
Commercial Loan Portfolio
Troubled debt restructurings on financing receivables with defaults payment
Number of loans (in loan) | loan	5	2	6
Principal balance at year end | $	$ 1,617	$ 1,721	$ 2,222
Consumer Loan Portfolio
Troubled debt restructurings on financing receivables with defaults payment
Number of loans (in loan) | loan	17	14	3
Principal balance at year end | $	$ 434	$ 259	$ 65
Commercial | Commercial Loan Portfolio
Troubled debt restructurings on financing receivables with defaults payment
Number of loans (in loan) | loan	5	0	1
Principal balance at year end | $	$ 1,617	$ 0	$ 1,206
Commercial real estate | Commercial Loan Portfolio
Troubled debt restructurings on financing receivables with defaults payment
Number of loans (in loan) | loan	0	2	5
Principal balance at year end | $	$ 0	$ 1,721	$ 1,016