Stock-Based Compensation Stock-Based Compensation Expense (Details) (USD $)	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Pre-tax compensation expense	$ 4,500,000	$ 3,100,000
Tax provision	1,700,000	1,200,000
Total stock-based compensation expense, net of tax	2,800,000	1,900,000
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized	14,400,000
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Period for Recognition (in years)	1.3
Employee Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized	12,300,000
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Period for Recognition (in years)	1.2
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Options, outstanding, beginning of period	1,318,640
Options, granted	147,674
Options, exercised	(164,954)
Options, forfeited	(13,335)
Options, outstanding, end of period	1,288,025
Options, vested and expected to vest	1,220,562
Options, exercisable	812,691
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Roll Forward]
Weighted average exercise price, beginning of period	$ 32.06
Weighted average exercise price, granted	$ 51.63
Weighted average exercise price, exercised	$ 12.40
Weighted average exercise price, forfeited	$ 44.44
Weighted average exercise price, end of period	$ 36.69
Weighted average exercise price, vested and expected to vest	$ 36.09
Weighted average exercise price, exercisable	$ 31.82
Weighted average remaining contractual term	6.89
Weighted average remaining contractual term, vested and expected to vest	6.77
Weighted average remaining contractual term, exercisable	5.68
Options, outstanding, intrinsic value	18,277,000
Options, vested and expected to vest, intrinsic value	17,958,000
Options, vested and expected to vest, exercisable	$ 14,914,000