Benefit Plans - Funded Status (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Jan. 01, 2017	Jan. 03, 2016
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	$ 257,790	$ 227,549
Noncurrent liabilities	118,392	126,679
Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligation	(303,918)	(273,148)	$ (261,469)
Plan assets at fair value	258,513	228,256	214,055
Net funded status	(45,405)	(44,892)
Noncurrent liabilities	45,405	44,892
Total liability - postretirement benefits	45,405	44,892
Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligation	(76,665)	(85,255)	(70,361)
Plan assets at fair value	0	0	$ 0
Current liabilities	3,678	3,468
Noncurrent liabilities	72,987	81,787
Total liability - postretirement benefits	$ 76,665	$ 85,255