Loans - Impaired Loan Balances By Portfolio Segment (Details) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2016	Dec. 31, 2015
Recorded Investment [Abstract]
Impaired loan, with no related allowance, recorded investment	$ 1,598	$ 1,724
Impaired loan, with related allowance, recorded investment	2,460	2,983
Impaired loan, total, recorded investment	4,058	4,707
Unpaid Principal Balance [Abstract]
Impaired loan, with no related allowance, unpaid principal balance	1,599	1,725
Impaired loan, with related allowance, unpaid principal balance	2,464	3,026
Impaired loan, total, unpaid principal balance	4,063	4,751
Impaired loan, total, related allowance	28	35
Average Recorded Investment [Abstract]
Impaired loan, with no related allowance, average recorded investment	1,228	2,216
Impaired loan, with related allowance, average recorded investment	2,869	2,387
Impaired loan, total, average recorded investment	4,097	4,603
Interest Income Recognized [Abstract]
Impaired loan, with no related allowance, interest income recognized	43	1
Impaired loan, with related allowance, interest income recognized	29	65
Impaired loan, total, interest income recognized	72	66
Commercial [Member]
Recorded Investment [Abstract]
Impaired loan, with no related allowance, recorded investment	3	4
Impaired loan, with related allowance, recorded investment	98	91
Impaired loan, total, recorded investment	101	95
Unpaid Principal Balance [Abstract]
Impaired loan, with no related allowance, unpaid principal balance	3	4
Impaired loan, with related allowance, unpaid principal balance	98	91
Impaired loan, total, unpaid principal balance	101	95
Impaired loan, total, related allowance	0	0
Average Recorded Investment [Abstract]
Impaired loan, with no related allowance, average recorded investment	3	47
Impaired loan, with related allowance, average recorded investment	102	99
Impaired loan, total, average recorded investment	105	146
Interest Income Recognized [Abstract]
Impaired loan, with no related allowance, interest income recognized	0	0
Impaired loan, with related allowance, interest income recognized	1	0
Impaired loan, total, interest income recognized	1	0
Commercial real estate [Member] | Construction and land development [Member]
Recorded Investment [Abstract]
Impaired loan, with no related allowance, recorded investment	0	205
Impaired loan, with related allowance, recorded investment	291	448
Impaired loan, total, recorded investment	291	653
Unpaid Principal Balance [Abstract]
Impaired loan, with no related allowance, unpaid principal balance	0	205
Impaired loan, with related allowance, unpaid principal balance	291	449
Impaired loan, total, unpaid principal balance	291	654
Impaired loan, total, related allowance	4	6
Average Recorded Investment [Abstract]
Impaired loan, with no related allowance, average recorded investment	0	220
Impaired loan, with related allowance, average recorded investment	410	563
Impaired loan, total, average recorded investment	410	783
Interest Income Recognized [Abstract]
Impaired loan, with no related allowance, interest income recognized	0	0
Impaired loan, with related allowance, interest income recognized	10	26
Impaired loan, total, interest income recognized	10	26
Commercial real estate [Member] | Real estate [Member]
Recorded Investment [Abstract]
Impaired loan, with no related allowance, recorded investment	1,577	1,202
Impaired loan, with related allowance, recorded investment	384	390
Impaired loan, total, recorded investment	1,961	1,592
Unpaid Principal Balance [Abstract]
Impaired loan, with no related allowance, unpaid principal balance	1,577	1,206
Impaired loan, with related allowance, unpaid principal balance	384	391
Impaired loan, total, unpaid principal balance	1,961	1,597
Impaired loan, total, related allowance	2	3
Average Recorded Investment [Abstract]
Impaired loan, with no related allowance, average recorded investment	1,096	1,504
Impaired loan, with related allowance, average recorded investment	413	353
Impaired loan, total, average recorded investment	1,509	1,857
Interest Income Recognized [Abstract]
Impaired loan, with no related allowance, interest income recognized	40	1
Impaired loan, with related allowance, interest income recognized	7	17
Impaired loan, total, interest income recognized	47	18
Residential [Member] | Real estate [Member]
Recorded Investment [Abstract]
Impaired loan, with no related allowance, recorded investment	2	127
Impaired loan, with related allowance, recorded investment	1,415	1,649
Impaired loan, total, recorded investment	1,417	1,776
Unpaid Principal Balance [Abstract]
Impaired loan, with no related allowance, unpaid principal balance	3	124
Impaired loan, with related allowance, unpaid principal balance	1,420	1,690
Impaired loan, total, unpaid principal balance	1,423	1,814
Impaired loan, total, related allowance	22	0
Average Recorded Investment [Abstract]
Impaired loan, with no related allowance, average recorded investment	1	126
Impaired loan, with related allowance, average recorded investment	1,588	1,034
Impaired loan, total, average recorded investment	1,589	1,160
Interest Income Recognized [Abstract]
Impaired loan, with no related allowance, interest income recognized	2	0
Impaired loan, with related allowance, interest income recognized	9	22
Impaired loan, total, interest income recognized	11	22
Residential [Member] | Home equity [Member]
Recorded Investment [Abstract]
Impaired loan, with no related allowance, recorded investment	6	173
Impaired loan, with related allowance, recorded investment	271	397
Impaired loan, total, recorded investment	277	570
Unpaid Principal Balance [Abstract]
Impaired loan, with no related allowance, unpaid principal balance	6	173
Impaired loan, with related allowance, unpaid principal balance	270	396
Impaired loan, total, unpaid principal balance	276	569
Impaired loan, total, related allowance	0	25
Average Recorded Investment [Abstract]
Impaired loan, with no related allowance, average recorded investment	117	305
Impaired loan, with related allowance, average recorded investment	341	327
Impaired loan, total, average recorded investment	458	632
Interest Income Recognized [Abstract]
Impaired loan, with no related allowance, interest income recognized	1	0
Impaired loan, with related allowance, interest income recognized	2	0
Impaired loan, total, interest income recognized	3	0
Consumer [Member]
Recorded Investment [Abstract]
Impaired loan, with no related allowance, recorded investment	10	13
Impaired loan, with related allowance, recorded investment	1	8
Impaired loan, total, recorded investment	11	21
Unpaid Principal Balance [Abstract]
Impaired loan, with no related allowance, unpaid principal balance	10	13
Impaired loan, with related allowance, unpaid principal balance	1	9
Impaired loan, total, unpaid principal balance	11	22
Impaired loan, total, related allowance	0	1
Average Recorded Investment [Abstract]
Impaired loan, with no related allowance, average recorded investment	11	14
Impaired loan, with related allowance, average recorded investment	15	11
Impaired loan, total, average recorded investment	26	25
Interest Income Recognized [Abstract]
Impaired loan, with no related allowance, interest income recognized	0	0
Impaired loan, with related allowance, interest income recognized	0	0
Impaired loan, total, interest income recognized	$ 0	$ 0