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Stock Based Compensation (Details Textual) - USD ($)
12 Months Ended
Feb. 16, 2017
Feb. 15, 2017
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Jun. 10, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Maximum shares of common stock provided           8,700,000
Aggregate intrinsic value     $ 29,400,000      
Aggregate intrinsic value exercisable     $ 13,600,000      
Quoted closing market price     $ 25.76      
Weighted average contractual term     1 year 1 month 39 days      
Total intrinsic value of options exercised     $ 1,600,000 $ 1,300,000 $ 200,000  
Tax related benefits realized from the exercise of stock options     500,000.0 300,000 100,000.0  
Stock-based compensation expense     12,362,000 9,450,000 5,524,000  
Stock based long term liability     1,400,000 0 1,400,000  
Stock based current liability     0 1,000,000 0  
Unrecognized compensation expense related to unvested stock options     $ 6,900,000      
Weighted average remaining requisite service period of unvested stock awards     1 year 10 months 24 days      
Fair value of option shares vested     $ 3,000,000 1,300,000 1,500,000  
Options granted     668,000      
Restricted stock or unit expenses       0 3,023,000  
Aggregate intrinsic value for the restricted stock and restricted stock units outstanding     $ 28,900,000      
Tax benefits recognized for stock based compensation     $ 4,300,000 3,400,000 1,900,000  
Minimum [Member]            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Vesting period of shares     3 years      
Maximum [Member]            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Vesting period of shares     4 years      
Class A [Member]            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Maximum shares that may be issued pursuant to options or restricted stock grants     3,481,569      
Restricted stock [Member]            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Weighted average remaining requisite service period of unvested stock awards     1 year 9 months 4 days      
Restricted stock or unit expenses     $ 6,600,000 4,700,000 3,000,000  
Unrecognized compensation expense related to unvested restricted stock and restricted stock units     12,500,000      
Fair value of restricted stock and restricted stock units vested     $ 4,600,000 800,000 900,000  
Stock options [Member]            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Maximum vesting period     5 years      
Maximum vesting period     10 years      
Stock-based compensation expense     $ 5,900,000 $ 4,700,000 $ 2,500,000  
Subsequent Event [Member]            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Options granted 444,491 590,128        
Share Based Compensation Arrangement By Share Based Payment Award Options and Restricted Stock Grants In Period Fair Value $ 9,300,000 $ 12,400,000        
Subsequent Event [Member] | Restricted stock [Member]            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Vesting period of shares 3 years 3 years        
Restricted stock grants 174,561 228,174        
Weighted average fair value, Granted $ 26.86 $ 27.26        
Subsequent Event [Member] | Stock options [Member]            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Vesting period of shares 3 years 3 years        
Weighted average fair value, Granted $ 26.86 $ 27.26