Stockholders' Equity (Summary Of Stock Option Activity) (Details) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2011
Stockholders' Equity [Abstract]
Shares, Outstanding at January 1, 2011	24,028,688
Shares, Granted	4,404,965
Shares, Exercised	(1,954,840)
Shares, Forfeited	(429,950)
Shares, Expired	(980,051)
Shares, Outstanding at December 31, 2011	25,068,812
Shares, Vested and expected to vest at December 31, 2011	24,331,795
Shares, Exercisable at December 31, 2011	17,017,555
Weighted-Average Exercise Price, Outstanding at January 1, 2011	$ 14.55
Weighted-Average Exercise Price, Granted	$ 25.57
Weighted-Average Exercise Price, Exercised	$ 8.69
Weighted-Average Exercise Price, Forfeited	$ 22.40
Weighted-Average Exercise Price, Expired	$ 39.28
Weighted-Average Exercise Price, Outstanding at December 31, 2011	$ 15.84
Weighted-Average Exercise Price, Vested and expected to vest at December 31, 2011	$ 15.66
Weighted-Average Exercise Price, Exercisable at December 31, 2011	$ 12.40
Weighted-Average Remaining Contractual Term (years), Outstanding at January 1, 2011	6.32
Weighted-Average Remaining Contractual Term (years), Outstanding at December 31, 2011	6.24
Weighted-Average Remaining Contractual Term (years), Vested and expected to vest at December 31, 2011	6.17
Weighted-Average Remaining Contractual Term (years), Exercisable at December 31, 2011	5.14
Aggregate Intrinsic Value, Outstanding at January 1, 2011	$ 275,278	[1]
Aggregate Intrinsic Value, Exercised	32,946	[1]
Aggregate Intrinsic Value, Outstanding at December 31, 2011	25,815	[1]
Aggregate Intrinsic Value, Vested and expected to vest at December 31, 2011	24,941	[1]
Aggregate Intrinsic Value, Exercisable at December 31, 2011	$ 18,023	[1]

[1] Aggregate intrinsic value includes only options in which the exercise price of the option is less than the market value of the Company's stock on December 31, 2011, or for exercised options, the intrinsic value on the exercise date.