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Pension Plans and Other Retirement Benefits - Additional Information (Detail) - USD ($)
$ in Millions
3 Months Ended 6 Months Ended
Apr. 29, 2016
Jul. 29, 2017
Pension Plans and Other Retirement Benefits [Line Items]    
Minimum percentage of pension liability   80.00%
Anticipated employer's contribution to fund current benefit and expense payments under the unfunded plan in fiscal 2018   $ 4.1
Post Retirement Medical Plan    
Pension Plans and Other Retirement Benefits [Line Items]    
Pre-tax income from post retirement medical plan reflected in income statement $ 5.5