Loans and Allowance (Activity in Allowance for Loan Losses by Portfolio Segment) (Details) - USD ($) $ in Thousands	3 Months Ended									12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses, Beginning of period				$ 12,382				$ 12,641		$ 12,382	$ 12,641	$ 13,168
Provision charged (credited) to expense	$ 350	$ 370	$ 300	200	$ 250	$ 250	$ 150	200	$ 125	1,220	850	125
Losses charged off										(1,412)	(1,482)	(1,387)
Recoveries										197	373	735
Allowance for loan losses, End of period	12,387				12,382				12,641	12,387	12,382	12,641
Allowance for loan losses, individually evaluated for impairment, Ending balance													$ 100	$ 100	$ 100
Allowance for loan losses, collectively evaluated for impairment, Ending balance													12,287	12,282	12,541
Total allowance for loan losses	12,387			12,382	12,382			12,641	12,641	12,382	12,641	13,168	12,387	12,382	12,641
Loans, individually evaluated for impairment, Ending balance													3,607	3,757	6,700
Loans, collectively evaluated for impairment, Ending balance													1,183,106	1,168,879	1,076,695
Total loans receivable													1,186,713	1,172,636	1,083,395
Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses, Beginning of period				7,358				7,090		7,358	7,090	7,085
Provision charged (credited) to expense										483	457	(389)
Losses charged off										(161)	(274)	(104)
Recoveries										24	85	498
Allowance for loan losses, End of period	7,704				7,358				7,090	7,704	7,358	7,090
Allowance for loan losses, individually evaluated for impairment, Ending balance													100	100	100
Allowance for loan losses, collectively evaluated for impairment, Ending balance													7,604	7,258	6,990
Total allowance for loan losses	7,704			7,358	7,358			7,090	7,090	7,358	7,090	7,085	7,704	7,358	7,090
Loans, individually evaluated for impairment, Ending balance													2,064	1,888	5,093
Loans, collectively evaluated for impairment, Ending balance													475,863	454,245	370,589
Total loans receivable													477,927	456,133	375,682
Mortgage [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses, Beginning of period				2,303				2,683		2,303	2,683	3,471
Provision charged (credited) to expense										(271)	15	(179)
Losses charged off										(284)	(420)	(643)
Recoveries										13	25	34
Allowance for loan losses, End of period	1,761				2,303				2,683	1,761	2,303	2,683
Allowance for loan losses, collectively evaluated for impairment, Ending balance													1,761	2,303	2,683
Total allowance for loan losses	1,761			2,303	2,303			2,683	2,683	2,303	2,683	3,471	1,761	2,303	2,683
Loans, individually evaluated for impairment, Ending balance													1,543	1,869	1,126
Loans, collectively evaluated for impairment, Ending balance													442,700	476,979	490,325
Total loans receivable													444,243	478,848	491,451
Consumer Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses, Beginning of period				2,721				2,868		2,721	2,868	2,612
Provision charged (credited) to expense										1,008	378	693
Losses charged off										(967)	(788)	(640)
Recoveries										160	263	203
Allowance for loan losses, End of period	2,922				2,721				2,868	2,922	2,721	2,868
Allowance for loan losses, collectively evaluated for impairment, Ending balance													2,922	2,721	2,868
Total allowance for loan losses	$ 2,922			$ 2,721	$ 2,721			$ 2,868	$ 2,868	$ 2,721	$ 2,868	$ 2,612	2,922	2,721	2,868
Loans, individually evaluated for impairment, Ending balance															481
Loans, collectively evaluated for impairment, Ending balance													264,543	237,655	215,781
Total loans receivable													$ 264,543	$ 237,655	$ 216,262