Stock-Based Compensation (Summary Of Combined Stock Option Activity) (Details) (Stock Options [Member], USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2011 years
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options outstanding as of January 1, 2011, Shares	3,003,000
Granted, Shares	342,000
Exercised, Shares	(669,000)
Forfeited/Cancelled, Shares	(144,000)
Options outstanding as of December 31, 2011, Shares	2,532,000
Vested and expected to vest as of December 31, 2011, Shares	2,279,000
Exercisable as of December 31, 2011, Shares	1,727,000
Options outstanding as of January 1, 2011, Weighted-average exercise price	$ 12.54
Granted, Weighted-average exercise price	$ 31.10
Exercised, Weighted-average exercise price	$ 9.33
Forfeited/Cancelled, Weighted-average exercise price	$ 15.63
Options outstanding as of December 31, 2011, Weighted-average exercise price	$ 15.46
Vested and expected to vest as of December 31, 2011, Weighted-average exercise price	$ 14.48
Exercisable as of December 31, 2011, Weighted-average exercise price	$ 10.66
Vested and expected to vest as of December 31, 2011, Weighted-average remaining contractual term (in years)	5.13
Exercisable as of December 31, 2011, Weighted-average remaining contractual term (in years)	4.06
Vested and expected to vest as of December 31, 2011, Aggregate intrinsic value	$ 35,513
Exercisable as of December 31, 2011, Aggregate intrinsic value	$ 32,829