Pension Benefits - Changes in Benefit Obligation and Plan Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 26, 2021
Amount recognized in the Consolidated Balance Sheets
Pension assets	$ 83,016	$ 69,521
Pension Plan
Change in benefit obligation
Benefit obligation at beginning of year	1,256,020	1,714,954
Service cost	5,742	11,631	$ 9,200
Interest cost	66,011	40,492	34,869
Actuarial loss/(gain)	47,205	(420,944)
Benefits paid	(125,964)	(90,036)
Effects of change in currency conversion	31	(77)
Benefit obligation at end of year	1,249,045	1,256,020	1,714,954
Change in plan assets
Fair value of plan assets at beginning of year	1,145,933	1,550,078
Actual return on plan assets	104,595	(343,215)
Employer contributions	26,941	29,106
Benefits paid	(125,964)	(90,036)
Fair value of plan assets at end of year	1,151,505	1,145,933	1,550,078
Net amount recognized	(97,540)	(110,087)
Amount recognized in the Consolidated Balance Sheets
Pension assets	83,016	69,521
Current liabilities	(16,672)	(16,361)
Noncurrent liabilities	(163,884)	(163,247)
Net amount recognized	(97,540)	(110,087)
Amount recognized in accumulated other comprehensive loss
Actuarial loss	520,304	507,397
Prior service credit	(8,573)	(10,468)
Total	511,731	496,929
Qualified Plans | Pension Plan
Change in benefit obligation
Benefit obligation at beginning of year	1,076,412	1,475,764
Service cost	5,669	11,526	9,105
Interest cost	56,793	35,350	30,517
Actuarial loss/(gain)	39,116	(374,109)
Benefits paid	(109,501)	(72,119)
Effects of change in currency conversion	0	0
Benefit obligation at end of year	1,068,489	1,076,412	1,475,764
Change in plan assets
Fair value of plan assets at beginning of year	1,145,933	1,550,078
Actual return on plan assets	104,595	(343,215)
Employer contributions	10,478	11,189
Benefits paid	(109,501)	(72,119)
Fair value of plan assets at end of year	1,151,505	1,145,933	1,550,078
Net amount recognized	83,016	69,521
Amount recognized in the Consolidated Balance Sheets
Pension assets	83,016	69,521
Current liabilities	0	0
Noncurrent liabilities	0	0
Net amount recognized	83,016	69,521
Amount recognized in accumulated other comprehensive loss
Actuarial loss	446,500	438,145
Prior service credit	(9,062)	(11,007)
Total	437,438	427,138
Non- Qualified Plans | Pension Plan
Change in benefit obligation
Benefit obligation at beginning of year	179,608	239,190
Service cost	73	105	95
Interest cost	9,218	5,142	4,352
Actuarial loss/(gain)	8,089	(46,835)
Benefits paid	(16,463)	(17,917)
Effects of change in currency conversion	31	(77)
Benefit obligation at end of year	180,556	179,608	239,190
Change in plan assets
Fair value of plan assets at beginning of year	0	0
Actual return on plan assets	0	0
Employer contributions	16,463	17,917
Benefits paid	(16,463)	(17,917)
Fair value of plan assets at end of year	0	0	$ 0
Net amount recognized	(180,556)	(179,608)
Amount recognized in the Consolidated Balance Sheets
Pension assets	0	0
Current liabilities	(16,672)	(16,361)
Noncurrent liabilities	(163,884)	(163,247)
Net amount recognized	(180,556)	(179,608)
Amount recognized in accumulated other comprehensive loss
Actuarial loss	73,804	69,252
Prior service credit	489	539
Total	$ 74,293	$ 69,791