Loans - Impaired Loan Balances By Portfolio Segment (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2015	Dec. 31, 2014
Recorded Investment [Abstract]
Impaired loan, with no related allowance, recorded investment	$ 3,202	$ 2,667
Impaired loan, with an related allowance, recorded investment	1,147	1,870
Impaired loan, total, recorded investment	4,349	4,537
Unpaid Principal Balance [Abstract]
Impaired loan, with no related allowance, unpaid principal balance	3,578	2,989
Impaired loan, with an related allowance, unpaid principal balance	1,147	2,018
Impaired loan, total, unpaid principal balance	4,725	5,007
Impaired loan, total, related allowance	34	165
Average Recorded Investment [Abstract]
Impaired loan, with no related allowance, average recorded investment	3,464	3,345
Impaired loan, with related allowance, average recorded investment	1,095	1,911
Impaired loan, total, average recorded investment	4,559	5,256
Interest Income Recognized [Abstract]
Impaired loan, with no related allowance, interest income recognized	1	9
Impaired loan, with related allowance, interest income recognized	43	43
Impaired loan, total, interest income recognized	44	52
Commercial [Member]
Recorded Investment [Abstract]
Impaired loan, with no related allowance, recorded investment	107	7
Impaired loan, with an related allowance, recorded investment	0	0
Impaired loan, total, recorded investment	107	7
Unpaid Principal Balance [Abstract]
Impaired loan, with no related allowance, unpaid principal balance	108	7
Impaired loan, with an related allowance, unpaid principal balance	0	0
Impaired loan, total, unpaid principal balance	108	7
Impaired loan, total, related allowance	0	0
Average Recorded Investment [Abstract]
Impaired loan, with no related allowance, average recorded investment	203	12
Impaired loan, with related allowance, average recorded investment	0	0
Impaired loan, total, average recorded investment	203	12
Interest Income Recognized [Abstract]
Impaired loan, with no related allowance, interest income recognized	0	1
Impaired loan, with related allowance, interest income recognized	0	0
Impaired loan, total, interest income recognized	0	1
Construction and land development [Member]
Recorded Investment [Abstract]
Impaired loan, with no related allowance, recorded investment	249	280
Impaired loan, with an related allowance, recorded investment	413	576
Impaired loan, total, recorded investment	662	856
Unpaid Principal Balance [Abstract]
Impaired loan, with no related allowance, unpaid principal balance	306	325
Impaired loan, with an related allowance, unpaid principal balance	413	577
Impaired loan, total, unpaid principal balance	719	902
Impaired loan, total, related allowance	2	12
Average Recorded Investment [Abstract]
Impaired loan, with no related allowance, average recorded investment	382	448
Impaired loan, with related allowance, average recorded investment	484	593
Impaired loan, total, average recorded investment	866	1,041
Interest Income Recognized [Abstract]
Impaired loan, with no related allowance, interest income recognized	0	0
Impaired loan, with related allowance, interest income recognized	21	34
Impaired loan, total, interest income recognized	21	34
Commercial real estate [Member]
Recorded Investment [Abstract]
Impaired loan, with no related allowance, recorded investment	1,108	1,520
Impaired loan, with an related allowance, recorded investment	249	1,275
Impaired loan, total, recorded investment	1,357	2,795
Unpaid Principal Balance [Abstract]
Impaired loan, with no related allowance, unpaid principal balance	1,425	1,797
Impaired loan, with an related allowance, unpaid principal balance	249	1,422
Impaired loan, total, unpaid principal balance	1,674	3,219
Impaired loan, total, related allowance	6	149
Average Recorded Investment [Abstract]
Impaired loan, with no related allowance, average recorded investment	1,524	1,844
Impaired loan, with related allowance, average recorded investment	254	1,297
Impaired loan, total, average recorded investment	1,778	3,141
Interest Income Recognized [Abstract]
Impaired loan, with no related allowance, interest income recognized	0	0
Impaired loan, with related allowance, interest income recognized	12	8
Impaired loan, total, interest income recognized	12	8
Residential [Member]
Recorded Investment [Abstract]
Impaired loan, with no related allowance, recorded investment	920	603
Impaired loan, with an related allowance, recorded investment	379	4
Impaired loan, total, recorded investment	1,299	607
Unpaid Principal Balance [Abstract]
Impaired loan, with no related allowance, unpaid principal balance	921	603
Impaired loan, with an related allowance, unpaid principal balance	379	4
Impaired loan, total, unpaid principal balance	1,300	607
Impaired loan, total, related allowance	24	1
Average Recorded Investment [Abstract]
Impaired loan, with no related allowance, average recorded investment	626	723
Impaired loan, with related allowance, average recorded investment	333	4
Impaired loan, total, average recorded investment	959	727
Interest Income Recognized [Abstract]
Impaired loan, with no related allowance, interest income recognized	0	8
Impaired loan, with related allowance, interest income recognized	10	0
Impaired loan, total, interest income recognized	10	8
Home equity [Member]
Recorded Investment [Abstract]
Impaired loan, with no related allowance, recorded investment	803	256
Impaired loan, with an related allowance, recorded investment	106	0
Impaired loan, total, recorded investment	909	256
Unpaid Principal Balance [Abstract]
Impaired loan, with no related allowance, unpaid principal balance	803	256
Impaired loan, with an related allowance, unpaid principal balance	106	0
Impaired loan, total, unpaid principal balance	909	256
Impaired loan, total, related allowance	2	0
Average Recorded Investment [Abstract]
Impaired loan, with no related allowance, average recorded investment	695	316
Impaired loan, with related allowance, average recorded investment	24	0
Impaired loan, total, average recorded investment	719	316
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
Consumer [Member]
Recorded Investment [Abstract]
Impaired loan, with no related allowance, recorded investment	15	1
Impaired loan, with an related allowance, recorded investment	0	15
Impaired loan, total, recorded investment	15	16
Unpaid Principal Balance [Abstract]
Impaired loan, with no related allowance, unpaid principal balance	15	1
Impaired loan, with an related allowance, unpaid principal balance	0	15
Impaired loan, total, unpaid principal balance	15	16
Impaired loan, total, related allowance	0	3
Average Recorded Investment [Abstract]
Impaired loan, with no related allowance, average recorded investment	34	2
Impaired loan, with related allowance, average recorded investment	0	17
Impaired loan, total, average recorded investment	34	19
Interest Income Recognized [Abstract]
Impaired loan, with no related allowance, interest income recognized	1	0
Impaired loan, with related allowance, interest income recognized	0	1
Impaired loan, total, interest income recognized	$ 1	$ 1