Condensed Statement of Shareholders' Equity (Unaudited) (USD $) In Thousands, unless otherwise specified	Total	Preferred Stock	Common Stock	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Treasury Stock
Balance at beginning of period at Dec. 31, 2011	$ 206,657	$ 0	$ 166,969	$ 53,580	$ 1,412	$ (15,304)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	16,511			16,511
Other comprehensive loss, net of tax	(661)				(661)
Repurchase of common stock warrant	(1,201)		(1,201)
Common stock cash dividends declared	(3,522)			(3,522)
Excess tax benefit from share-based payments	13		13
Reissuance of treasury stock for deferred compensation plan	163					163
Purchase of treasury stock	(80)					(80)
Common shares issued under dividend reinvestment plan	264		264
Common shares issued under Board of Directors' compensation plan	89		(35)			124
Stock based compensation expense	602		602
Balance at end of period at Sep. 30, 2012	$ 218,835	$ 0	$ 166,612	$ 66,569	$ 751	$ (15,097)