Employee Benefit Plans (Components of Net Periodic Benefit Costs) (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Apr. 01, 2018
Pension and SERPA Benefits
Defined Benefit Plan Disclosure
Service cost	$ 6,632	$ 8,155
Interest cost	21,371	20,590
Expected return on plan assets	(35,581)	(36,891)
Amortization of unrecognized: Prior service credit	(483)	(106)
Amortization of unrecognized: Net loss	11,128	15,819
Curtailment loss	0	1,018
Net periodic benefit cost	3,067	8,585
Postretirement Healthcare Benefits
Defined Benefit Plan Disclosure
Service cost	1,184	1,812
Interest cost	2,938	2,897
Expected return on plan assets	(3,507)	(3,541)
Amortization of unrecognized: Prior service credit	(595)	(460)
Amortization of unrecognized: Net loss	69	454
Net periodic benefit cost	89	1,162
Pension and postretirement benefit plans
Defined Benefit Plan Disclosure
Other comprehensive income before reclassifications	$ 0	$ 96,374