Loans and Allowance for Loan Losses, Allowance for Loan Losses by Portfolio Segment (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended	12 Months Ended
Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Allowance for Loan Losses [Roll Forward]
Beginning balance			$ 5,094	$ 4,525	$ 4,525
Charge-offs			(505)	(585)	(691)
Recoveries			77	54	740
Provision (recovery)	$ 12	$ 235	312	285	520
Ending balance	4,978	4,279	4,978	4,279	5,094
Additional Information on Allowance for Loan Losses and Recorded Investment in Loans Receivable [Abstract]
Ending balances individually evaluated for impairment	514		514		912
Ending balances collectively evaluated for impairment	4,464		4,464		4,182
Loans receivable, individually evaluated for impairment	8,461		8,461		10,862
Loans receivable, collectively evaluated for impairment	502,140		502,140		491,937
Total financing receivables	510,601		510,601		502,799
Commercial and Industrial [Member]
Allowance for Loan Losses [Roll Forward]
Beginning balance			518	561	561
Charge-offs			(88)	(15)	(19)
Recoveries			14	49	154
Provision (recovery)			(15)	(109)	(178)
Ending balance	429	486	429	486	518
Additional Information on Allowance for Loan Losses and Recorded Investment in Loans Receivable [Abstract]
Ending balances individually evaluated for impairment	79		79		247
Ending balances collectively evaluated for impairment	350		350		271
Loans receivable, individually evaluated for impairment	642		642		758
Loans receivable, collectively evaluated for impairment	28,111		28,111		23,655
Total financing receivables	28,753		28,753		24,413
Commercial Real Estate [Member]
Allowance for Loan Losses [Roll Forward]
Beginning balance			1,609	1,569	1,569
Charge-offs			0	(477)	(476)
Recoveries			10	0	575
Provision (recovery)			217	255	(59)
Ending balance	1,836	1,347	1,836	1,347	1,609
Additional Information on Allowance for Loan Losses and Recorded Investment in Loans Receivable [Abstract]
Ending balances individually evaluated for impairment	372		372		257
Ending balances collectively evaluated for impairment	1,464		1,464		1,352
Loans receivable, individually evaluated for impairment	3,593		3,593		3,631
Loans receivable, collectively evaluated for impairment	174,406		174,406		173,196
Total financing receivables	177,999		177,999		176,827
Construction and Land [Member]
Allowance for Loan Losses [Roll Forward]
Beginning balance			879	661	661
Charge-offs			(312)	0	0
Recoveries			0	0	0
Provision (recovery)			(115)	132	218
Ending balance	452	793	452	793	879
Additional Information on Allowance for Loan Losses and Recorded Investment in Loans Receivable [Abstract]
Ending balances individually evaluated for impairment	22		22		357
Ending balances collectively evaluated for impairment	430		430		522
Loans receivable, individually evaluated for impairment	2,929		2,929		5,234
Loans receivable, collectively evaluated for impairment	49,949		49,949		48,928
Total financing receivables	52,878		52,878		54,162
Consumer [Member]
Allowance for Loan Losses [Roll Forward]
Beginning balance			105	21	21
Charge-offs			(10)	(30)	(114)
Recoveries			4	1	2
Provision (recovery)			10	54	196
Ending balance	109	46	109	46	105
Additional Information on Allowance for Loan Losses and Recorded Investment in Loans Receivable [Abstract]
Ending balances individually evaluated for impairment	0		0		0
Ending balances collectively evaluated for impairment	109		109		105
Loans receivable, individually evaluated for impairment	0		0		0
Loans receivable, collectively evaluated for impairment	4,580		4,580		5,068
Total financing receivables	4,580		4,580		5,068
Student [Member]
Allowance for Loan Losses [Roll Forward]
Beginning balance			72	76	76
Charge-offs			(15)	(12)	(31)
Recoveries			0	0	0
Provision (recovery)			21	17	27
Ending balance	78	81	78	81	72
Additional Information on Allowance for Loan Losses and Recorded Investment in Loans Receivable [Abstract]
Ending balances individually evaluated for impairment	0		0		0
Ending balances collectively evaluated for impairment	78		78		72
Loans receivable, individually evaluated for impairment	0		0		0
Loans receivable, collectively evaluated for impairment	9,995		9,995		10,677
Total financing receivables	9,995		9,995		10,677
Residential Real Estate [Member]
Allowance for Loan Losses [Roll Forward]
Beginning balance			1,174	943	943
Charge-offs			0	(51)	(51)
Recoveries			48	3	6
Provision (recovery)			77	71	276
Ending balance	1,299	966	1,299	966	1,174
Additional Information on Allowance for Loan Losses and Recorded Investment in Loans Receivable [Abstract]
Ending balances individually evaluated for impairment	0		0		0
Ending balances collectively evaluated for impairment	1,299		1,299		1,174
Loans receivable, individually evaluated for impairment	719		719		581
Loans receivable, collectively evaluated for impairment	192,913		192,913		186,523
Total financing receivables	193,632		193,632		187,104
Home Equity Lines of Credit [Member]
Allowance for Loan Losses [Roll Forward]
Beginning balance			387	307	307
Charge-offs			(80)	0	0
Recoveries			1	1	3
Provision (recovery)			117	103	77
Ending balance	425	411	425	411	387
Additional Information on Allowance for Loan Losses and Recorded Investment in Loans Receivable [Abstract]
Ending balances individually evaluated for impairment	41		41		51
Ending balances collectively evaluated for impairment	384		384		336
Loans receivable, individually evaluated for impairment	578		578		658
Loans receivable, collectively evaluated for impairment	42,186		42,186		43,890
Total financing receivables	42,764		42,764		44,548
Unallocated [Member]
Allowance for Loan Losses [Roll Forward]
Beginning balance			350	387	387
Charge-offs			0	0	0
Recoveries			0	0	0
Provision (recovery)			0	(238)	(37)
Ending balance	350	$ 149	350	$ 149	350
Additional Information on Allowance for Loan Losses and Recorded Investment in Loans Receivable [Abstract]
Ending balances individually evaluated for impairment	0		0		0
Ending balances collectively evaluated for impairment	350		350		350
Loans receivable, individually evaluated for impairment	0		0		0
Loans receivable, collectively evaluated for impairment	0		0		0
Total financing receivables	$ 0		$ 0		$ 0

Amount of recovery of loans and lease receivables which had previously been fully or partially written-off as bad debts.

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Amount of loans and leases that have been written off from both loan receivables and allowance reserve for credit loss.

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The valuation allowance for financing receivables that are expected to be uncollectible that were collectively evaluated for impairment.

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Amount of valuation allowance for financing receivables that are expected to be uncollectible that were individually evaluated for impairment.

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The balance of financing receivables that were collectively evaluated for impairment.

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Amount of allowance to cover probable credit losses on loans and leases. Includes carryover of or adjustments to the allowance for loan losses in connection with business combinations. Excludes allowance for loans and leases covered under loss sharing agreements.

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Amount before allowance of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Includes deferred interest and fees, undisbursed portion of loan balance, unamortized costs and premiums and discounts from face amounts. Excludes loans and leases covered under loss sharing agreements.

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Amount of expense related to estimated loss from loan and lease transactions.

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