Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 29, 2018	Dec. 30, 2017	Dec. 31, 2016
Statement Of Income And Comprehensive Income [Abstract]
Net income	$ 157,160	$ 150,120	$ 163,776
Pension and postretirement plans:
Settlement loss	5,816	3,072	4,087
Net loss for the period	(19,831)	(2,637)	(4,013)
Amortization of prior service credit included in net income	130	108	108
Amortization of actuarial loss included in net income	4,022	3,603	4,206
Pension and postretirement plans, net of tax	(9,863)	4,146	4,388
Derivative instruments:
Net change in fair value of derivatives	2,978	(6,789)	5,730
Loss reclassified to net income	1,079	1,367	3,399
Derivative instruments, net of tax	4,057	(5,422)	9,129
Other comprehensive income (loss), net of tax	(5,806)	(1,276)	13,517
Comprehensive income	$ 151,354	$ 148,844	$ 177,293