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Stock-Based Awards - Performance Awards Information (Details) - USD ($)
1 Months Ended 12 Months Ended
Mar. 31, 2017
Jul. 31, 2016
Feb. 29, 2016
Feb. 28, 2015
Jul. 31, 2014
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                
Share-based compensation expense           $ 65,830,000 $ 54,699,000 $ 43,081,000
Performance awards                
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                
Award vesting period 3 years 3 years            
Share-based compensation expense           11,200,000 $ 2,600,000 $ 1,900,000
Unrecognized compensation expense           0    
Performance based restricted stock units                
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                
Award vesting period     3 years   3 years      
Expected to vest (in shares)       535,000 40,600      
Aggregated grant date fair value         $ 1,800,000      
Performance based restricted stock units | Maximum                
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                
Expected to vest (in shares)       1,070,000 60,900      
Tranche One | Performance based restricted stock units                
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                
Aggregated grant date fair value       $ 9,900,000   4,800,000    
Tranche Two | Performance based restricted stock units                
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                
Aggregated grant date fair value     $ 3,600,000     $ 9,800,000