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Stock Options, Restricted Stock Units and Employee Stock Purchase Plan - Additional Information (Details)
3 Months Ended 5 Months Ended 9 Months Ended
Sep. 30, 2017
USD ($)
shares
Sep. 30, 2016
USD ($)
shares
Sep. 30, 2017
shares
Sep. 30, 2017
USD ($)
offering_period
shares
Sep. 30, 2016
USD ($)
shares
Apr. 27, 2017
shares
May 02, 2014
shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Number of options granted (in Shares)     0        
Exercise of stock options (in Shares) 100,000 200,000   600,000 1,700,000    
Proceeds from stock options exercised | $ $ 2,300,000 $ 3,200,000   $ 9,300,000 $ 13,000,000    
Tax benefit from compensation expense | $ $ 2,600,000 $ 3,300,000   $ 9,400,000 $ 39,800,000    
Restricted stock units              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Annual award vesting percentage       25.00%      
Award vesting period       4 years      
Number of unit granted (in Shares)       666,000      
Omnibus Plan              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Number of shares available for issuance (in Shares)           8,000,000  
2014 Plan              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Number of shares reserved for issuance (in Shares)             7,500,000
Employee Stock Purchase Plan ESPP              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Number of shares reserved for issuance (in Shares) 2,000,000   2,000,000 2,000,000      
Discount from market price at the beginning or end of the offering period       15.00%      
Number of offering periods | offering_period       2      
Maximum annual purchase per employee under ESPP | $       $ 25,000      
Maximum annual withholdings per employee for purchases under ESPP | $       $ 21,250      
Maximum number of shares available for purchase per employee (in Shares)       15,000      
Contributions from plan participants through payroll deductions | $       $ 2,200,000      
Employee Stock Purchase Plan ESPP | Minimum              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Percentage of base wages withheld for purchase of stock       1.00%      
Employee Stock Purchase Plan ESPP | Maximum              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Percentage of base wages withheld for purchase of stock       15.00%