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		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Accounting Policies [Abstract]
Basic earnings per common share, Income (Numerator)	$ 82,813	$ 83,494	$ 157,633	$ 155,414
Shares used to compute basic earnings per share	168,606	172,223	168,956	172,411
Basic earnings per common share	$ 0.49	$ 0.48	$ 0.93	$ 0.90
Dilutive effect of stock options, income	0	0	0	0
Dilutive effect of stock options, shares	3,698	3,835	4,110	3,621
Diluted earnings per common share, Income (Numerator)	$ 82,813	$ 83,494	$ 157,633	$ 155,414
Shares used to compute diluted earnings per share	172,304	176,058	173,066	176,032
Diluted earnings per common share	$ 0.48	$ 0.47	$ 0.91	$ 0.88