Consolidated Statements of Changes in Stockholders' Equity - USD ($) $ in Thousands	Common Stock [Member]	Retained Earnings [Member]	AOCI Attributable to Parent [Member]	Total
Balance at Dec. 31, 2013	$ 8,685	$ 154,171	$ (16,964)	$ 145,892
Net income		16,914		16,914
Other comprehensive income (loss), net of tax			11,292	11,292
Cash dividend		(7,853)		(7,853)
Exercise of stock options	3	55		58
Balance at Dec. 31, 2014	8,688	163,287	(5,672)	166,303
Net income		15,833		15,833
Other comprehensive income (loss), net of tax			(2,265)	(2,265)
Cash dividend		(7,930)		(7,930)
Exercise of stock options	10	163		173
Balance at Dec. 31, 2015	8,698	171,353	(7,937)	172,114
Net income		14,942		14,942
Other comprehensive income (loss), net of tax			(722)	(722)
Cash dividend		(8,071)		(8,071)
Balance at Dec. 31, 2016	$ 8,698	$ 178,224	$ (8,659)	$ 178,263