Benefit Plans - Reconciliation of Amounts in Accumulated Other Comprehensive Loss That Have Not Yet Been Recognized as Components of Net Periodic Benefit Cost (Detail) $ in Thousands	12 Months Ended
	Jan. 01, 2017 USD ($)
Defined Benefit Plan Disclosure [Line Items]
Actuarial gain (loss)	$ (18,929)
Net periodic benefit cost, beginning balance	(137,079)
Reclassification Adjustments, Net periodic benefit cost	1,883
Net periodic benefit cost, ending balance	(154,125)
Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Actuarial loss, beginning balance	(112,898)
Actuarial gain (loss)	(9,777)
Reclassification Adjustments, Actuarial loss	3,031
Actuarial loss, ending balance	(119,644)
Prior service cost (credit), beginning balance	(128)
Reclassification Adjustments, Prior service cost (credit)	27
Prior service cost (credit), ending balance	(101)
Postretirement Medical [Member]
Defined Benefit Plan Disclosure [Line Items]
Actuarial loss, beginning balance	(33,536)
Actuarial gain (loss)	(9,152)
Reclassification Adjustments, Actuarial loss	2,186
Actuarial loss, ending balance	(40,502)
Prior service cost (credit), beginning balance	9,483
Reclassification Adjustments, Prior service cost (credit)	(3,361)
Prior service cost (credit), ending balance	$ 6,122