Share Based Compensation (Summary Of Changes In The Number Of Shares Of Common Stock Under Option) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2012
Share Based Compensation [Abstract]
Shares, Outstanding, Beginning Balance	8,341
Weighted Average Exercise Price, Outstanding, Beginning balance	$ 15.51
Options Exercisable at End of Period, Outstanding, Beginning Balance	4,394
Weighted Average Exercise Price of Exercisable Options, Outstanding, Beginning Balance	$ 10.13
Aggregate Intrinsic Value, Outstanding, Beginning Balance	$ 119,802
Shares, Exercised	(1,019)
Weighted Average Exercise Price, Exercised	$ 7.77
Aggregate Intrinsic Value, Exercised	31,607
Shares, Forfeited	(30)
Weighted Average Exercise Price, Forfeited	$ 10.00
Shares, Outstanding, Ending Balance	7,292
Weighted Average Exercise Price, Outstanding, Ending balance	$ 16.61
Options Exercisable at End of Year, Outstanding, Ending Balance	3,716
Weighted Average Exercise Price of Exercisable Options, Outstanding, Ending Balance	$ 11.09
Aggregate Intrinsic Value, Outstanding, Ending Balance	$ 161,530
Shares, Expected to vest	7,292
Weighted Average Exercise Price, Expected to vest	$ 16.61