Earnings Per Common Share (Computation Of Basic And Diluted Earnings Per Share) (Details) (USD $) In Thousands, except Per Share data	3 Months Ended		9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Earnings Per Common Share
Income available to common stockholders and holders of dilutive securities	$ 43,614	$ 45,452	$ 132,756	$ 135,503
Weighted average shares	88,563	95,214	91,196	95,666
Effect of dilutive securities: Incremental shares under stock compensation plans	1,980	1,491	2,311	1,823
Adjusted weighted average shares	90,543	96,705	93,507	97,489
Per share amount, basic	$ 0.49	$ 0.48	$ 1.46	$ 1.42
Per share amount, diluted	$ 0.48	$ 0.47	$ 1.42	$ 1.39