Stock-Based Compensation Restricted Stock Units Summary (Details) (Restricted Stock Units (RSUs) [Member], USD $) In Thousands, except Share data, unless otherwise specified	9 Months Ended
	Sep. 30, 2012		Sep. 30, 2011
Restricted Stock Units (RSUs) [Member]
[Line Items]
Outstanding, beginning balance, Number	625,000		588,000
Granted, Number	452,000	[1]	286,000	[1]
Granted, Weighted Average Grant Date Fair Value	$ 47.29	[1]	$ 54.82	[1]
Released, Number	(207,000)		(201,000)
Released, Aggregate Intrinsic Value	$ 12,835	[2]	$ 15,739	[2]
Forfeited, Number	(34,000)		(37,000)
Outstanding, ending balance, Number	836,000		636,000
Vested, Number	48,000
Vested, Aggregate Intrinsic Value	2,049	[2]
Expected to vest, Number	763,000
Expected to vest, Aggregate Intrinsic Value	$ 32,904	[2]

[1] These restricted stock units do not include the respective 2011 and 2012 awards under the Performance Award Agreement, which are not eligible for vesting as of September 30 of each respective year.

[2] The aggregate intrinsic value is the market value of the stock, before applicable income taxes, based on the closing price on the stock release dates or at the end of the period for restricted stock units expected to vest.