Retirement Plans - Components of Net Periodic Benefit Costs for Pension and Other Postretirement Benefits (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Oct. 01, 2016	Sep. 30, 2017	Oct. 01, 2016
Pension Benefits [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Service cost	$ 755	$ 962	$ 1,767	$ 2,887
Interest cost	9,329	10,114	29,606	30,344
Expected return on plan assets	(11,943)	(12,072)	(35,871)	(36,220)
Amortization of prior service cost	35	39	104	118
Amortization of net loss (gain)	785	2,063	2,886	6,191
Settlements	1,000	750	3,000	2,250
Net periodic benefit costs (credits)	(39)	1,856	1,492	5,570
Other Postretirement Benefits [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Service cost	7	9	26	28
Interest cost	68	73	212	221
Amortization of prior service cost	2	2	5	5
Amortization of net loss (gain)	(86)	(17)	(112)	(53)
Net periodic benefit costs (credits)	$ (9)	$ 67	$ 131	$ 201