Consolidated Statements of Shareholders' Equity (USD $) In Thousands	Total	Common Stock	Capital Surplus	Accum. Other Comprehensive Income	Retained Earnings	Treasury Stock	Comprehensive Income
Balance at Dec. 31, 2009	$ 895,973	$ 569	$ 494,318	$ 6,925	$ 843,521	$ (449,360)
Comprehensive Income:
Net Income	99,300				99,300		99,300
Other Comprehensive Income, Net of Tax:
Net Unrealized Gains (Losses) on Investment Securities, Net of Reclassification Adjustment	53,534			53,534			53,534
Amortization of Net Losses Related to Defined Benefit Plans	761			761			761
Total Comprehensive Income	153,595						153,595
Share-Based Compensation	1,545		1,545
Common Stock Issued under Purchase and Equity Compensation Plans and Related Tax Benefits (237,619 and 312,707 shares for the six months ended June 30, 2011 and 2010 respectively)	8,532	1	1,219		(3,902)	11,214
Common Stock Repurchased (1,109,988 and 67,493 shares for the six months ended June 30, 2011 and 2010 respectively)	(3,280)					(3,280)
Cash Dividends Paid ($0.90 per share)	(43,354)				(43,354)
Balance at Jun. 30, 2010	1,013,011	570	497,082	61,220	895,565	(441,426)
Balance at Dec. 31, 2010	1,011,133	570	500,888	26,965	932,629	(449,919)
Comprehensive Income:
Net Income	77,508				77,508		77,508
Other Comprehensive Income, Net of Tax:
Net Unrealized Gains (Losses) on Investment Securities, Net of Reclassification Adjustment	(235)			(235)			(235)
Amortization of Net Losses Related to Defined Benefit Plans	1,048			1,048			1,048
Total Comprehensive Income	78,321						78,321
Share-Based Compensation	1,360		1,360
Common Stock Issued under Purchase and Equity Compensation Plans and Related Tax Benefits (237,619 and 312,707 shares for the six months ended June 30, 2011 and 2010 respectively)	7,829	1	529		(2,752)	10,051
Common Stock Repurchased (1,109,988 and 67,493 shares for the six months ended June 30, 2011 and 2010 respectively)	(52,228)					(52,228)
Cash Dividends Paid ($0.90 per share)	(42,965)				(42,965)
Balance at Jun. 30, 2011	$ 1,003,450	$ 571	$ 502,777	$ 27,778	$ 964,420	$ (492,096)