Condensed Consolidated Statements of Comprehensive Income (Loss) (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Oct. 06, 2018	Oct. 07, 2017	Oct. 06, 2018	Oct. 07, 2017
Statement Of Income And Comprehensive Income [Abstract]
Net income (loss)	$ 39,630	$ (33,571)	$ 136,319	$ 71,587
Pension and postretirement plans:
Settlement loss	696	1,863	4,959	1,863
Net loss for the period	(32,639)	(2,707)	(19,883)	(2,707)
Amortization of prior service cost included in net income	35	21	96	79
Amortization of actuarial loss included in net income	768	769	2,709	2,712
Pension and postretirement plans, net of tax	(31,140)	(54)	(12,119)	1,947
Derivative instruments:
Net change in fair value of derivatives	7,394	(9,652)	9,055	(5,932)
Loss reclassified to net income	266	372	689	1,166
Derivative instruments, net of tax	7,660	(9,280)	9,744	(4,766)
Other comprehensive loss, net of tax	(23,480)	(9,334)	(2,375)	(2,819)
Comprehensive income (loss)	$ 16,150	$ (42,905)	$ 133,944	$ 68,768