Loans (Narrative) (Details)	12 Months Ended
	Dec. 31, 2017 USD ($) loan	Dec. 31, 2016 USD ($) loan	Dec. 31, 2015 USD ($) loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of loans modified as debt restructurings | loan	3	0	0
Troubled debt restructuring, additional lending amount	$ 0	$ 0
Number of loans that subsequently default after modification | loan	0	0	0
Mortgage loans in process of foreclosure	$ 14,000	$ 202,000
Loans Acquired with Deteriorated Credit Quality
Accounts, Notes, Loans and Financing Receivable [Line Items]
Increase in allowance for loans that subsequently default after modification	11,000	107,000	$ 0
Loans Purchased
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses, reversal	$ 110,000	$ 2,000	$ 54,000