Non-Vested Stock Activity (Detail) - $ / shares
 12 Months Ended
Dec. 31, 2015
Dec. 31, 2014
Dec. 31, 2013
Non-Vested Stock [Member]      
Share Based Compensation [Line Items]      
Non-vested Stock Outstanding, Beginning Balance 917,959    
Non-vested Stok Granted, Number of Shares 93,256    
Non-vested Stock Vested, Number of Shares (355,396)    
Non-vested Stock Canceled, Forfeited or Expired, Number of Shares (154,931)    
Non-vested Stock Outstanding, Ending Balance 500,888 917,959  
Non-vested Stock Outstanding, Beginning Balance, Weighted Average Grant Date Fair Value $ 15.17    
Non-vested Stock Granted, Weighted Average Grant Date Fair Value 28.48 $ 16.38 $ 10.91
Non-vested Stock Vested, Weighted Average Grant Date Fair Value 14.69    
Non-vested Stock Canceld, Forfeited or Expired, Weighted Average Grant Date Fair Value 14.34    
Non-vested Stock Outstanding, Ending Balance, Weighted Average Grant Date Fair Value $ 18.24 15.17  
Non-Vested Stock Units - Service-Based and Performance-Based [Member]      
Share Based Compensation [Line Items]      
Non-vested Stok Granted, Number of Shares 154,732    
Non-vested Stock Vested, Number of Shares 0    
Non-vested Stock Canceled, Forfeited or Expired, Number of Shares (3,669)    
Non-vested Stock Outstanding, Ending Balance 151,063    
Non-vested Stock Outstanding, Beginning Balance, Weighted Average Grant Date Fair Value $ 0.00    
Non-vested Stock Granted, Weighted Average Grant Date Fair Value 39.54    
Non-vested Stock Vested, Weighted Average Grant Date Fair Value 0    
Non-vested Stock Canceld, Forfeited or Expired, Weighted Average Grant Date Fair Value 43.63    
Non-vested Stock Outstanding, Ending Balance, Weighted Average Grant Date Fair Value $ 39.44 $ 0.00  
Non-Vested Stock Units - Service-Based and Market-Based [Member]      
Share Based Compensation [Line Items]      
Non-vested Stock Outstanding, Beginning Balance 225,745    
Non-vested Stok Granted, Number of Shares 0    
Non-vested Stock Vested, Number of Shares 0    
Non-vested Stock Canceled, Forfeited or Expired, Number of Shares (61,211)    
Non-vested Stock Outstanding, Ending Balance 164,534 225,745  
Non-vested Stock Outstanding, Beginning Balance, Weighted Average Grant Date Fair Value $ 10.51    
Non-vested Stock Granted, Weighted Average Grant Date Fair Value 0    
Non-vested Stock Vested, Weighted Average Grant Date Fair Value 0    
Non-vested Stock Canceld, Forfeited or Expired, Weighted Average Grant Date Fair Value 10.51    
Non-vested Stock Outstanding, Ending Balance, Weighted Average Grant Date Fair Value $ 10.51 $ 10.51  
Non Vested Stock Units Service [Member]      
Share Based Compensation [Line Items]      
Non-vested Stock Outstanding, Beginning Balance 0    
Non-vested Stok Granted, Number of Shares 186,314    
Non-vested Stock Vested, Number of Shares 0    
Non-vested Stock Canceled, Forfeited or Expired, Number of Shares (2,982)    
Non-vested Stock Outstanding, Ending Balance 183,332 0  
Non-vested Stock Outstanding, Beginning Balance, Weighted Average Grant Date Fair Value $ 0.00    
Non-vested Stock Granted, Weighted Average Grant Date Fair Value 37.98    
Non-vested Stock Vested, Weighted Average Grant Date Fair Value 0    
Non-vested Stock Canceld, Forfeited or Expired, Weighted Average Grant Date Fair Value 43.63    
Non-vested Stock Outstanding, Ending Balance, Weighted Average Grant Date Fair Value $ 37.89 $ 0.00