Condensed Financial Statements of Parent Company, Balance Sheets (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Assets [Abstract]
Cash and cash equivalents	$ 14,412	$ 25,854	$ 36,990	$ 33,305
Securities available-for-sale	157,121	199,365
Other assets	12,777	15,543
Total assets	981,826	902,966	896,787
Liabilities and Stockholders' Equity [Abstract]
Common stock	25,087	24,806
Additional paid-in capital	17,270	16,427
Retained earnings	54,738	56,965
Accumulated other comprehensive loss	(707)	(4,208)
Total liabilities and stockholders' equity	981,826	902,966
Parent Company [Member]
Assets [Abstract]
Cash and cash equivalents	2,622	2,366	$ 2,198	$ 1,349
Securities available-for-sale	197	164
Investment in common stock of subsidiaries	93,533	91,437
Other assets	54	31
Total assets	96,406	93,998
Liabilities and Stockholders' Equity [Abstract]
Note payable - subsidiary	18	8
Common stock	25,087	24,806
Additional paid-in capital	17,270	16,427
Retained earnings	54,738	56,965
Accumulated other comprehensive loss	(707)	(4,208)
Total liabilities and stockholders' equity	$ 96,406	$ 93,998