Parent Company Only Financial Statements Condensed Parent Company Only Income Statement (Details) - USD ($) $ in Thousands	3 Months Ended												12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Condensed Financial Statements, Captions [Line Items]
Interest-bearing deposits with banks													$ 235	$ 274	$ 115
Total interest income	$ 11,409	$ 10,842	$ 9,896	$ 9,562	$ 9,464	$ 9,358	$ 9,221	$ 9,154	$ 9,606	$ 9,736	$ 9,695	$ 9,652	41,709	37,197	38,689
Total interest expense	2,105	1,908	1,713	1,781	1,772	1,694	1,653	1,632	1,609	1,517	1,517	1,598	7,507	6,751	6,241
Loss before provision for federal income taxes and equity in undistributed earnings of subsidiaries	4,344	3,453	2,219	2,588	3,643	3,430	3,551	3,423	4,584	4,197	3,664	4,098	12,604	14,047	16,543
Federal income tax provision	1,323	847	779	763	1,526	984	1,183	1,194	1,644	1,462	1,297	1,453	3,712	4,887	5,856
Net income	$ 3,021	$ 2,606	$ 1,440	$ 1,825	$ 2,117	$ 2,446	$ 2,368	$ 2,229	$ 2,940	$ 2,735	$ 2,367	$ 2,645	8,892	9,160	10,687
Parent Company [Member]
Condensed Financial Statements, Captions [Line Items]
Interest-bearing deposits with banks													92	143	26
Other Income													0	2	8
Total interest income													92	145	34
Total interest expense													1,913	1,440	1,475
Loss before provision for federal income taxes and equity in undistributed earnings of subsidiaries													(1,821)	(1,295)	(1,441)
Federal income tax provision													(701)	(601)	(573)
Loss before equity in undistributed loss of subsidiaries													(1,120)	(694)	(868)
Equity in undistributed earnings of subsidiaries													10,012	9,854	11,555
Net income													$ 8,892	$ 9,160	$ 10,687