Parent Company Financial Information - Consolidated Balance Sheets (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Consolidated Balance Sheets [Abstract]
Securities available for sale, at fair value	$ 321,337	$ 346,502
Total assets	1,816,078	1,678,638	$ 1,547,599
Trust preferred capital notes	27,826	27,724
Shareholders' equity	208,717	201,380	$ 197,835	$ 173,780
Total liabilities and shareholders' equity	1,816,078	1,678,638
Parent Company
Consolidated Balance Sheets [Abstract]
Cash	1,597	4,654
Securities available for sale, at fair value	8,740	8,355
Investment in subsidiaries	226,452	216,340
Due from subsidiaries	46	120
Other assets	31	40
Total assets	236,866	229,509
Trust preferred capital notes	27,826	27,724
Other liabilities	323	405
Shareholders' equity	208,717	201,380
Total liabilities and shareholders' equity	$ 236,866	$ 229,509