Allowance For Loan Losses And Credit Quality Of Financing Receivables - Changes In The Allowance For Loan Losses (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance	$ 6,797	$ 5,812	$ 6,696	$ 5,590
Charge-offs	(16)	(228)	(334)	(256)
Recoveries	4	19	16	58
Provision	380	385	787	596
Ending balance	7,165	5,988	7,165	5,988
Commercial And Industrial [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance	92	98	110	85
Charge-offs	0	(138)	(13)	(138)
Recoveries	0	9	0	16
Provision	109	230	104	236
Ending balance	201	199	201	199
Construction [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance	425	267	359	220
Provision	53	(59)	119	(12)
Ending balance	478	208	478	208
Commercial Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance	4,025	3,847	3,932	3,646
Charge-offs	0	(65)	(266)	(65)
Recoveries	2	3	4	34
Provision	216	235	573	405
Ending balance	4,243	4,020	4,243	4,020
Residential Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance	925	908	899	784
Charge-offs	(8)	(25)	(42)	(34)
Recoveries	1	6	9	6
Provision	(1)	25	51	158
Ending balance	917	914	917	914
Consumer And Other [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance	17	121	19	87
Charge-offs	(8)	0	(13)	(19)
Recoveries	1	1	3	2
Provision	10	(105)	11	(53)
Ending balance	20	17	20	17
Unallocated [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance	1,313	571	1,377	768
Provision	(7)	59	(71)	(138)
Ending balance	$ 1,306	$ 630	$ 1,306	$ 630