Benefit Plans - Components of Net Periodic Postretirement Benefit Cost (Detail) - Postretirement Benefits [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Jan. 01, 2017	Jan. 03, 2016
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 2,232	$ 1,567	$ 1,118
Interest cost	3,636	3,094	2,878
Recognized net actuarial loss	2,942	2,186	3,164
Amortization of prior service cost	(2,982)	(3,360)	(3,360)
Net periodic pension cost (benefit)	$ 5,828	$ 3,487	$ 3,800