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Stock Option Plans - Additional information (Detail) - USD ($)
 3 Months Ended 9 Months Ended
Mar. 16, 2017
Mar. 17, 2016
Sep. 30, 2017
Sep. 30, 2016
Sep. 30, 2017
Sep. 30, 2016
Stock Option Plans [Line Items]            
Compensation expense related to stock option grants     $ 4,400,000 $ 3,800,000 $ 12,900,000 $ 10,900,000
Total intrinsic value of options exercised         28,300,000 $ 14,900,000
Total unrecognized compensation cost related to nonvested options     $ 47,400,000   $ 47,400,000  
Weighted average period, years         4 years  
Long Term Incentive Plan [Member]            
Stock Option Plans [Line Items]            
Maximum number of shares available         4,000,000  
Maximum number of shares granted during any fiscal year to any person         200,000  
Shares available for grant     16,100,000   16,100,000  
2014 Long Term Incentive Plan [Member]            
Stock Option Plans [Line Items]            
Number of years options expire from date of grant         7 years 7 years
Officer and Key Employees [Member] | 2014 Long Term Incentive Plan [Member]            
Stock Option Plans [Line Items]            
Shares available for grant 1,650,400 2,576,700        
Stock options granted, exercise percentage, on the third anniversary date of the grant 34.00% 34.00%        
Stock options granted, exercise percentage, on the fourth anniversary date of the grant 33.00% 33.00%        
Stock options granted, exercise percentage, on the fifth anniversary date of the grant 33.00% 33.00%        
Minimum [Member] | Long Term Incentive Plan [Member]            
Stock Option Plans [Line Items]            
Minimum exercise price of stock options, percent of fair market value of a share of common stock on the date of grant         100.00%  
Minimum [Member] | 2014 Long Term Incentive Plan [Member]            
Stock Option Plans [Line Items]            
Period of service from grant date stock options awarded not subject to forfeiture         2 years 2 years
Minimum [Member] | Executive Officer [Member] | 2014 Long Term Incentive Plan [Member]            
Stock Option Plans [Line Items]            
Minimum age of employee with not subject to award forfeiture on condition compliance         55 years 55 years
Maximum [Member] | Long Term Incentive Plan [Member]            
Stock Option Plans [Line Items]            
Maximum period for the exercise of stock options, years         7 years  
Options or Stock Appreciation Rights [Member]            
Stock Option Plans [Line Items]            
Maximum number of shares granted during any fiscal year to any person         200,000  
Cash Settled Performance Shares [Member] | Long Term Incentive Plan [Member]            
Stock Option Plans [Line Items]            
Maximum amount payable for the shares granted during any fiscal year to any person         $ 5,000,000  
Black-Scholes Option Pricing Model [Member]            
Stock Option Plans [Line Items]            
Weighted average fair value per option for all options         $ 11.42 $ 8.45