Benefit Plans - Amounts in Accumulated Other Comprehensive Loss Expected to be Recognized as Components of Net Periodic Pension Costs or Postretirement Benefits Costs in 2015 (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 28, 2014
Defined Benefit Plan Disclosure [Line Items]
Actuarial loss	$ 6,052
Prior service cost (credit)	(3,325)
Net periodic benefit expected to be recognized	2,727
Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Actuarial loss	3,182
Prior service cost (credit)	35
Net periodic benefit expected to be recognized	3,217
Postretirement Medical [Member]
Defined Benefit Plan Disclosure [Line Items]
Actuarial loss	2,870
Prior service cost (credit)	(3,360)
Net periodic benefit expected to be recognized	$ (490)