Summary Of Significant Accounting Policies (Calculation Of Basic And Diluted Earnings Per Share) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Accounting Policies [Abstract]
Basic earnings per common share, Income (Numerator)	$ 67,195	$ 50,743	$ 222,609	$ 150,263
Shares used to compute basic earnings per share	171,308	173,429	172,043	174,869
Basic earnings per common share	$ 0.39	$ 0.29	$ 1.29	$ 0.86
Dilutive effect of stock options, income	0	0	0	0
Dilutive effect of stock options, shares	4,735	1,940	3,993	1,448
Diluted earnings per common share, Income (Numerator)	$ 67,195	$ 50,743	$ 222,609	$ 150,263
Shares used to compute diluted earnings per share	176,043	175,369	176,036	176,317
Diluted earnings per common share	$ 0.38	$ 0.29	$ 1.26	$ 0.85