Allowance for Credit Losses (Allowance For Credit Losses And Recorded Investments In Loans Receivables) (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	$ 5,843	$ 5,373	$ 5,373
Charge-offs	(76)	(349)
Recoveries	3	69
Provisions	375	325
Ending balance	6,145	5,418	5,843
Ending balance: individually evaluated for impairment	174		157
Ending balance: collectively evaluated for impairment	5,971		5,686
Ending balance: Loans receivables	864,345		845,897
Ending Balance: individually evaluated for impairment	9,518		8,187
Ending Balance: collectively evaluated for impairment	854,041		836,767
Reserve for unfunded loan commitments included in other liabilities	309	376	348
Receivables Acquired with Deteriorated Credit Quality [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Ending balance: Loans receivables	786		943
Residential Mortgage [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	221	349	349
Charge-offs	(34)
Recoveries	1	2
Provisions	38	(104)
Ending balance	226	247	221
Ending balance: individually evaluated for impairment			3
Ending balance: collectively evaluated for impairment	226		218
Ending balance: Loans receivables	95,404		93,959
Ending Balance: individually evaluated for impairment	2,296		1,908
Ending Balance: collectively evaluated for impairment	93,108		92,044
Residential Mortgage [Member] | Receivables Acquired with Deteriorated Credit Quality [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Ending balance: Loans receivables			7
Commercial Mortgage [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	2,856	2,531	2,531
Charge-offs	(13)	(234)
Recoveries		50
Provisions	144	250
Ending balance	2,987	2,597	2,856
Ending balance: individually evaluated for impairment	24		19
Ending balance: collectively evaluated for impairment	2,963		2,837
Ending balance: Loans receivables	498,506		484,868
Ending Balance: individually evaluated for impairment	2,791		2,828
Ending Balance: collectively evaluated for impairment	494,929		481,104
Reserve for unfunded loan commitments included in other liabilities	3	10	2
Commercial Mortgage [Member] | Receivables Acquired with Deteriorated Credit Quality [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Ending balance: Loans receivables	786		936
Commercial Term [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	845	709	709
Charge-offs	(17)	(105)
Recoveries	2	16
Provisions	74	154
Ending balance	904	774	845
Ending balance: individually evaluated for impairment	142		123
Ending balance: collectively evaluated for impairment	762		722
Ending balance: Loans receivables	131,144		129,535
Ending Balance: individually evaluated for impairment	3,015		2,080
Ending Balance: collectively evaluated for impairment	128,129		127,455
Reserve for unfunded loan commitments included in other liabilities	150	147	155
Commercial Construction [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	1,128	969	969
Charge-offs
Provisions	91	90
Ending balance	1,219	1,059	1,128
Ending balance: collectively evaluated for impairment	1,219		1,128
Ending balance: Loans receivables	78,863		75,014
Ending Balance: individually evaluated for impairment	497		514
Ending Balance: collectively evaluated for impairment	78,366		74,500
Reserve for unfunded loan commitments included in other liabilities	139	202	173
Leases Financing [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Charge-offs
Recoveries		1
Provisions		(1)
Consumer: Home Equity [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	183	196	196
Charge-offs
Provisions	(7)
Ending balance	176	196	183
Ending balance: collectively evaluated for impairment	176		183
Ending balance: Loans receivables	55,002		56,844
Ending Balance: individually evaluated for impairment	608		612
Ending Balance: collectively evaluated for impairment	54,394		56,232
Reserve for unfunded loan commitments included in other liabilities	17	17	18
Consumer: Other [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	63	61	61
Charge-offs	(12)	(10)
Provisions	4	12
Ending balance	55	63	63
Ending balance: individually evaluated for impairment	8		12
Ending balance: collectively evaluated for impairment	47		51
Ending balance: Loans receivables	5,426		5,677
Ending Balance: individually evaluated for impairment	311		245
Ending Balance: collectively evaluated for impairment	5,115		5,432
Unallocated [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	547	558	558
Charge-offs
Provisions	31	(76)
Ending balance	578	$ 482	547
Ending balance: collectively evaluated for impairment	$ 578		$ 547