Consolidated Statement of Changes in Shareholders' Equity (USD $) In Thousands	Common Stock	Surplus	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Treasury Stock	Total
Balance at Dec. 31, 2008	$ 110,802	$ 96,654	$ 637,152	$ (76,151)	$ (31,745)	$ 736,712
Balance, shares at Dec. 31, 2008	44,320,832
Net income	0	0	67,298	0	0	67,298
Other comprehensive income, net of tax	0	0	0	7,768	0	7,768
Total comprehensive income, net of tax						75,066
Stock based compensation expense	0	484	0	0	0	484
Purchase of treasury stock (74,703, 8,910 and 676 shares for the years ended 2009, 2010 and 2011 respectively)	0	0	0	0	(1,304)	(1,304)
Distribution of treasury stock for deferred compensation plan (30,902, 28,466 and 3,069 shares for the years ended 2009, 2010 and 2011 respectively)	0	0	0	0	536	536
Cash dividends ($1.17, $1.20 and $1.21 per share for the years ended 2009, 2010 and 2011 respectively)	0	0	(50,837)	0	0	(50,837)
Common stock options exercised (79,323, 164,341 and 40,447 shares for the years ended 2009, 2010 and 2011 respectively)	0	(1,858)	0	0	2,751	893
Fractional shares adjustment	(4)	4	0	0	0	0
Fractional shares adjustment, shares	(1,675)
Balance at Dec. 31, 2009	110,798	95,284	653,613	(68,383)	(29,762)	761,550
Balance, shares at Dec. 31, 2009	44,319,157
Net income	0	0	71,947	0	0	71,947
Other comprehensive income, net of tax	0	0	0	7,727	0	7,727
Total comprehensive income, net of tax						79,674
Stock based compensation expense	0	1,050	0	0	0	1,050
Purchase of treasury stock (74,703, 8,910 and 676 shares for the years ended 2009, 2010 and 2011 respectively)	0	0	0	0	(249)	(249)
Distribution of treasury stock for deferred compensation plan (30,902, 28,466 and 3,069 shares for the years ended 2009, 2010 and 2011 respectively)	0	0	0	0	520	520
Cash dividends ($1.17, $1.20 and $1.21 per share for the years ended 2009, 2010 and 2011 respectively)	0	0	(52,300)	0	0	(52,300)
Common stock options exercised (79,323, 164,341 and 40,447 shares for the years ended 2009, 2010 and 2011 respectively)	0	(2,903)	0	0	5,670	2,767
Balance at Dec. 31, 2010	110,798	93,431	673,260	(60,656)	(23,821)	793,012
Balance, shares at Dec. 31, 2010	44,319,157
Net income	0	0	75,610	0	0	75,610
Other comprehensive income, net of tax	0	0	0	(6,102)	0	(6,102)
Total comprehensive income, net of tax						69,508
Acquisition of Centra Financial Holdings, Inc.	16,371	145,049	0	0	0	161,420
Acquisition of Centra Financial Holdings, Inc., shares	6,548,473
Stock based compensation expense	0	1,133	0	0	0	1,133
Purchase of treasury stock (74,703, 8,910 and 676 shares for the years ended 2009, 2010 and 2011 respectively)	0	0	0	0	(18)	(18)
Distribution of treasury stock for deferred compensation plan (30,902, 28,466 and 3,069 shares for the years ended 2009, 2010 and 2011 respectively)	0	0	0	0	74	74
Cash dividends ($1.17, $1.20 and $1.21 per share for the years ended 2009, 2010 and 2011 respectively)	0	0	(56,827)	0	0	(56,827)
Common stock options exercised (79,323, 164,341 and 40,447 shares for the years ended 2009, 2010 and 2011 respectively)	0	(852)	0	0	1,394	542
Balance at Dec. 31, 2011	$ 127,169	$ 238,761	$ 692,043	$ (66,758)	$ (22,371)	$ 968,844
Balance, shares at Dec. 31, 2011	50,867,630