Employee Retirement and Profit Sharing Plans - Net Periodic Benefit Cost (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Amortizations:
Net periodic benefit cost	$ 6,717	$ 6,805	$ 6,594
Pension Plan
Components of net periodic benefit cost:
Service cost	3,007	3,173	3,631
Interest cost	11,709	12,171	13,736
Expected return on plan assets	(19,030)	(18,531)	(20,026)
Amortizations:
Prior service cost	706	857	856
Unrecognized net (gain) loss	10,325	8,822	8,544
Effect of settlement	0	313	0
Other	0	0	(147)
Net periodic benefit cost	$ 6,717	$ 6,805	$ 6,594