Stock Option Plans - Stock Option Information (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense recognized	$ 20,840,000	$ 12,207,000	$ 4,502,000
Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total intrinsic value of options exercised	57,700,000	23,900,000	19,500,000
Compensation expense recognized	17,200,000	10,300,000	3,800,000
Unrecognized compensation expense related to options	59,600,000
Unrecognized compensation expense, weighted-average period of recognition	2 years 8 months 1 day
Aggregate grant date fair value of stock options granted	$ 51,500,000	$ 28,400,000	$ 11,900,000