Consolidated Statements of Changes in Shareholders' Equity (Unaudited) - USD ($) $ in Thousands	Capital Stock [Member]	Surplus [Member]	Undivided Profits [Member]	Accumulated Other Comprehensive (Loss) Income [Member]	Treasury Stock [Member]	Total
Balance at Dec. 31, 2014	$ 98,945	$ 172,353	$ 166,745	$ (4,509)	$ (40,090)	$ 393,444
Net income	0	0	10,715	0	0	10,715
Other comprehensive income, net of tax	0	0	0	1,822	0	1,822
Cash dividend declared	0	0	(6,228)	0	0	(6,228)
Stock options exercised and related tax benefits	19	80	0	0	0	99
Purchase of treasury stock	0	0	0	0	(99)	(99)
Sale of treasury stock	0	(244)	0	0	919	675
Stock based compensation expense	0	48	0	0	0	48
Balance at Mar. 31, 2015	98,964	172,237	171,232	(2,687)	(39,270)	400,476
Balance at Dec. 31, 2015	98,973	171,443	184,009	(4,781)	(36,334)	413,310
Net income	0	0	10,409	0	0	10,409
Other comprehensive income, net of tax	0	0	0	4,854	0	4,854
Cash dividend declared	0	0	(6,259)	0	0	(6,259)
Sale of treasury stock	0	(386)	0	0	1,041	655
Stock based compensation expense	0	56	0	0	0	56
Balance at Mar. 31, 2016	$ 98,973	$ 171,113	$ 188,159	$ 73	$ (35,293)	$ 423,025