Condensed Consolidated Statements of Changes in Shareholders' Equity (Unaudited) - USD ($)	Preferred Stock [Member]	Common Stock [Member]	Retained Earnings [Member]	AOCI Attributable to Parent [Member]	Total
Begining Balances at Dec. 31, 2014	$ 0	$ 317,904,000	$ 10,218,000	$ 16,000	$ 328,138,000
Employee stock purchase plan		23,000			23,000
Dividend reinvestment plan		283,000			283,000
Stock option exercises		275,000			275,000
Stock grants to directors for retainer fees		402,000			402,000
Stock-based compensation expense		359			359
Share repurchase program		(9,110,000)			(9,110,000)
Cash dividends			(4,656,000)		(4,656,000)
Net income			13,204,000		13,204,000
Change in net unrealized holding gain on securities available for sale, net of tax effect				135,000	135,000
Change in fair value of interest rate swap, net of tax effect				(82,000)	(82,000)
Ending Balance at Jun. 30, 2015	0	310,136,000	18,766,000	69,000	328,971,000
Begining Balances at Dec. 31, 2015	0	304,819,000	27,722,000	1,263,000	333,804,000
Employee stock purchase plan		18,000			18,000
Dividend reinvestment plan		909,000			909,000
Stock option exercises		379,000			379,000
Stock grants to directors for retainer fees		327,000			327,000
Stock-based compensation expense		616			616
Share repurchase program		(3,732,000)			(3,732,000)
Cash dividends			(5,152,000)		(5,152,000)
Net income			15,983,000		15,983,000
Change in net unrealized holding gain on securities available for sale, net of tax effect				1,441,000	1,441,000
Change in fair value of interest rate swap, net of tax effect				(16,000)	(16,000)
Ending Balance at Jun. 30, 2016	$ 0	$ 303,336,000	$ 38,553,000	$ 2,688,000	$ 344,577,000