Other Comprehensive Income (Loss) Tax Effects Allocated to Each Component of Other Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Other Comprehensive Income, before Tax [Abstract]
Net unrealized holding gains (losses) arising during the period on investment securities available-for-sale, Before Tax Amount	$ 70	$ (276)	$ 923	$ 1,082
Reclassification adjustment for net gains on investment securities available-for-sale realized in net income, Before Tax Amount	(24)	(53)	(33)	(71)
Total other comprehensive income (loss), Before Tax Amount	46	(329)	890	1,011
Other Comprehensive Income, Tax [Abstract]
Net unrealized holding gains (losses) arising during the period on investment securities available-for-sale, Tax	(24)	94	(314)	(368)
Reclassification adjustment for net gains on investment securities available-for-sale realized in net income, Tax	8	18	11	24
Total other comprehensive income (loss), Tax	(16)	112	(303)	(344)
Net unrealized holding gains (losses) arising during the period on investment securities available-for-sale	46	(182)	609	714
Reclassification adjustment for net gains on sales of investment securities available-for-sale realized in net income	(16)	(35)	(22)	(47)
Total other comprehensive income (loss), Net of Tax Amount	$ 30	$ (217)	$ 587	$ 667