v2.4.0.8
Stock-based Compensation (Details) (USD $)
 0 Months Ended 12 Months Ended 12 Months Ended
Dec. 03, 2012
Dec. 31, 2013
Dec. 31, 2012
Dec. 31, 2011
Dec. 31, 2013
2006 Equity Compensation Plan
Dec. 03, 2012
2006 Equity Compensation Plan
Dec. 02, 2012
2006 Equity Compensation Plan
Dec. 31, 2013
2006 Equity Compensation Plan
Maximum
Dec. 31, 2013
2006 Equity Compensation Plan
Minimum
Dec. 31, 2013
Stock Options
Dec. 31, 2012
Stock Options
Dec. 31, 2011
Stock Options
Dec. 31, 2013
Restricted Stock
Dec. 31, 2012
Restricted Stock
Dec. 31, 2011
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                              
Common stock available under the plan (in shares)           5,400,000 3,000,000                
Maximum term of award granted (in years)         10 years                    
Vesting period of restricted stock, (in years)               5 years 1 year            
Stock split three-for-one       three-for-one                    
Weighted average fair value of options granted (in dollars per share)                   $ 11.54 $ 9.13 $ 6.58      
Weighted average assumptions [Abstract]                              
Expected term (in years)                   3 years 1 month 6 days 3 years 3 years      
Expected volatility (in hundredths)                   39.00% 46.00% 54.00%      
Risk-free interest rate (in hundredths)                   0.50% 0.30% 1.40%      
Expected dividend yield (in hundredths)                   0.00% 0.00% 0.00%      
Summary of option activity [Roll Forward]                              
Outstanding at beginning of period (in shares)                   438,693          
Granted (in shares)                   55,000          
Exercised (in shares)                   (229,506)          
Outstanding at end of period (in shares)                   264,187 438,693        
Exercisable at end of period (in shares)                   254,187          
Weighted average exercise price [Abstract]                              
Weighted average exercise price of options outstanding at beginning of period (in dollars per share)                   $ 10.72          
Weighted average exercise price of options granted (in dollars per share)                   $ 41.93          
Weighted average exercise price of options exercised (in dollars per share)                   $ 7.62          
Weighted average exercise price of options outstanding at end of period (in dollars per share)                   $ 19.90 $ 10.72        
Weighted average exercise price of options exercisable at end of period (in dollars per share)                   $ 18.94          
Weighted Average Remaining Contractual Life Abstract                              
Weighted-average remaining contractual life of options outstanding at end of period (in years)                   2 years 1 month 6 days          
Weighted-average remaining contractual life of options exercisable at end of period (in years)                   2 years          
Aggregate intrinsic value [Abstract]                              
Aggregate intrinsic value of options outstanding at end of period                   $ 10,133,000          
Aggregate intrinsic value of options exercisable at end of period                   9,994,000          
Aggregate intrinsic value of options exercised during the period                   8,300,000 9,614,000 5,768,000      
Summary of restricted stock activity [Roll Forward]                              
Nonvested at beginning of period (in shares)                         205,650    
Granted (in shares)                         126,000    
Vested (in shares)                         (73,500)    
Forfeited (in shares)                         (21,200)    
Nonvested at end of period (in shares)                         236,950 205,650  
Weighted average grant-date fair value [Abstract]                              
Weighted average grant-date fair value of nonvested shares at beginning of period (in dollars per share)                         $ 27.94    
Weighted average grant-date fair value of shares granted (in dollars per share)                         $ 46.80    
Weighted average grant-date fair value of shares vested (in dollars per share)                         $ 26.70    
Weighted average grant-date fair value of shares forfeited (in dollars per share)                         $ 37.25    
Weighted average grant-date fair value of nonvested shares at end of period (in dollars per share)                         $ 37.24 $ 27.94  
Total fair value of shares vested during the period                         2,868,000 2,644,000 255,000
Stock-based compensation costs [Abstract]                              
Stock-based compensation expense   3,560,000 2,044,000 2,889,000                      
Total unrecognized compensation cost   $ 6,606,000                          
Period over which unrecognized compensation cost is expected to be recognized (in years)   2 years 2 months 12 days