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Executive Benefit Agreements, Employee Savings Plans and Collective Bargaining Agreements - Additional Information (Detail)
 12 Months Ended
Dec. 31, 2016
USD ($)
Person
Deferred Compensation Arrangement With Individual Excluding Share Based Payments And Postretirement Benefits [Line Items]  
Death benefit payment term 10 years
Minimum amount of life insurance policies to be kept by the company for 2005 Agreement | $ $ 2,500,000
Collective Bargaining Agreements [Member]  
Deferred Compensation Arrangement With Individual Excluding Share Based Payments And Postretirement Benefits [Line Items]  
Number of persons employed 610
Number of persons represented by union under agreements 195