Stock-Based Compensation (Narrative) (Details) (USD $)	12 Months Ended
	Dec. 31, 2013 ShareBasedCompensationPlan	Dec. 31, 2012	Dec. 31, 2011
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of stock incentive plans	2
Stock incentive plan, vesting period	4 years
Number of options exercised	270,749
Stock-based compensation expense	$ 12,324,000	$ 11,110,000	$ 9,324,000
Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock incentive plan, vesting period	4 years
Weighted Average Grant Date Fair Value, Granted	$ 31.72	$ 21.73	$ 16.82
Stock-based compensation expense	8,100,000	5,500,000	2,900,000
Unrecognized compensation expense	8,600,000
Weighted-average period for recognition of compensation cost	2 years 9 months 18 days
Number of shares granted	268,265
Total fair value of restricted stock vested	7,100,000	0	0
Restricted Stock Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock incentive plan, vesting period	4 years
Weighted Average Grant Date Fair Value, Granted	$ 26.86	$ 28.30	$ 23.13
Stock-based compensation expense	4,100,000	5,500,000	5,900,000
Unrecognized compensation expense	3,500,000
Weighted-average period for recognition of compensation cost	2 years 2 months 12 days
Number of shares granted	97,401
Total fair value of restricted stock vested	8,100,000	15,100,000	11,500,000
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	100,000	100,000	500,000
Intrinsic value of options exercised	6,700,000	12,900,000	15,100,000
Tax benefits from options exercised	2,300,000	4,500,000	5,300,000
Cash received from option exercises	$ 2,600,000	$ 7,300,000	$ 11,400,000
Performance Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted Average Grant Date Fair Value, Granted	$ 27.43
Number of shares granted	247,798
2007 Stock Inventive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares of common stock authorized under the plan	5,179,393
Options granted, net of cancellation	416,500
Restricted shares granted, net of cancellations	4,102,458
Number of options exercised	232,275
2001 Stock Inventive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options granted, net of cancellation	6,438,172
Number of options exercised	6,099,962
Vesting Two Years From January 31 of Grant Year [Member] | Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock incentive plan, vesting period	24 months
Vesting percentage	50.00%
Vesting Three Years From January 31 of Grant Year [Member] | Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock incentive plan, vesting period	36 months
Vesting percentage	25.00%
Vesting Four Years From January 31 of Grant Year [Member] | Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock incentive plan, vesting period	48 months
Vesting percentage	25.00%