Loans and Allowance for Credit Losses (Allowance for Credit Losses on Financing Receivables) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Allowance for credit losses:
Beginning balance	$ 8,927	$ 8,309	$ 8,726	$ 8,316
Charge-offs	(846)	(440)	(1,163)	(1,010)
Recoveries	77	114	168	227
Net charge-offs	(769)	(326)	(995)	(783)
Provision	974	375	1,401	825
Ending balance	9,132	8,358	9,132	8,358
Commercial and Residential Real Estate Portfolio Segment [Member] | Construction Loans [Member]
Allowance for credit losses:
Beginning balance	2,290	1,753	2,787	1,646
Charge-offs	(25)	(13)	(54)	(254)
Recoveries	9	10	16	16
Net charge-offs	(16)	(3)	(38)	(238)
Provision	75	(6)	(400)	336
Ending balance	2,349	1,744	2,349	1,744
Residential Portfolio Segment [Member]
Allowance for credit losses:
Beginning balance	2,131	2,014	1,953	2,181
Charge-offs	(100)	(102)	(323)	(118)
Recoveries	10	33	21	67
Net charge-offs	(90)	(69)	(302)	(51)
Provision	55	90	445	(95)
Ending balance	2,096	2,035	2,096	2,035
Commercial Real Estate Portfolio Segment [Member]
Allowance for credit losses:
Beginning balance	2,912	3,257	2,610	2,999
Charge-offs		(265)		(503)
Recoveries	8	10	19	10
Net charge-offs	8	(255)	19	(493)
Provision	(118)	(131)	173	365
Ending balance	2,802	2,871	2,802	2,871
Commercial Portfolio Segment [Member]
Allowance for credit losses:
Beginning balance	1,338	585	1,145	558
Charge-offs	(706)	(58)	(771)	(125)
Recoveries	42	57	100	122
Net charge-offs	(664)	(1)	(671)	(3)
Provision	978	93	1,178	122
Ending balance	1,652	677	1,652	677
Consumer Portfolio Segment [Member]
Allowance for credit losses:
Beginning balance	256	177	231	156
Charge-offs	(15)	(2)	(15)	(10)
Recoveries	8	4	12	12
Net charge-offs	(7)	2	(3)	2
Provision	(16)	27	5	48
Ending balance	$ 233	206	$ 233	206
Unallocated Financing Receivables [Member]
Allowance for credit losses:
Beginning balance		523		776
Provision		302		49
Ending balance		$ 825		$ 825