Employee Benefit Plans (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share Based Awards, Cumulative Shares Issued	7,100,000		7,100,000
Share-based awards available for grant	900,000		900,000
Share-based compensation expense	$ 1,400,000	$ 3,100,000	$ 10,100,000	$ 8,200,000
Proceeds from Stock Options Exercised	6,400,000	8,500,000	6,352,000	8,488,000
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unamortized compensation costs	18,200,000		18,200,000
Unamortized compensation costs, period for recognition	2 years
Weighted-average grant date fair value			$ 8.93	$ 10.53
Options Outstanding [Roll Forward]
Options outstanding at January 1, 2014			5,509,246
Options outstanding at January 1, 2014, weighted average exercise price, beginning balance			$ 14.01
Options granted, shares			894,180
Options granted, weighted average exercise price			$ 23.41
Options exercised, shares			(458,545)
Options exercised, weighted average exercise price			$ 13.58
Options cancelled or forfeited, shares			(292,813)
Options cancelled or forfeited, weighted average exercise price			$ 20.09
Options outstanding at September 30, 2014	5,652,068		5,652,068
Options outstanding, weighted average exercise price, ending balance	$ 15.22		$ 15.22
Options exercisable at September 30, 2014, shares	3,130,278		3,130,278
Options exercisable at September 30, 2014, weighted average exercise price	$ 12.77		$ 12.77
Expected to vest after September 30, 2014	1,898,726		1,898,726
Expected to Vest, Weighted Average Exercise Price	$ 18.55		$ 18.55
Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unamortized compensation costs	$ 18,100,000		$ 18,100,000
Unamortized compensation costs, period for recognition	2 years
Unvested Shares [Roll Forward]
Unvested shares at January 1, 2014			629,518
Unvested shares at January 1, 2014, Weighted-average grant date fair value			$ 20.11
Unvested shares granted			579,918
Unvested shares ganted, Weighted-average grant date fair value			$ 23.55
Unvested shares vested			(186,788)
Unvested shares vested, Weighted-average grant date fair value			$ 19.45
Unvested shares cancelled/forfeited			(105,915)
Unvested shares cancelled/forfeited, Weighted-average grant date fair value			$ 22.59
Unvested shares at September 30, 2014	916,733		916,733
Unvested shares at September 30, 2014, Weighted-average grant date fair value	$ 22.29		$ 22.29
Performance Stock Units
Unvested Shares [Roll Forward]
Unvested shares at January 1, 2014			431,858
Unvested shares at January 1, 2014, Weighted-average grant date fair value			$ 0
Unvested shares granted			123,283
Unvested shares ganted, Weighted-average grant date fair value			$ 26.50
Unvested shares cancelled/forfeited			34,819
Unvested shares cancelled/forfeited, Weighted-average grant date fair value			$ 23.14
Unvested shares at September 30, 2014	520,322		520,322
Unvested shares at September 30, 2014, Weighted-average grant date fair value	$ 23.64		$ 23.64