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Profit Sharing, Retirement Savings Plans and Defined Benefit Pension Plans - Additional Information (Detail) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Defined Benefit Plan Disclosure [Line Items]      
Provisions charged from operations for the profit sharing plan and retirement savings plans $ 42.9 $ 55.3 $ 50.3
Contribution of common stock to profit sharing plan 830,600 787,500 965,200
Defined benefit pension plan corridor rate 10.00%    
Percentage of equity allocation, maximum 70.00%    
Percentage of fixed income allocation, minimum 30.00%    
Equity Security [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Equity securities, minimum 40.00%    
Equity securities, maximum 50.00%    
Fixed Income Securities [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Equity securities, minimum 50.00%    
Equity securities, maximum 60.00%