Benefit Plans - Benefit Plan Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 26, 2020	Dec. 28, 2019	Dec. 29, 2018
Change in fair value of plan assets:
Beginning balance	$ 183,486
Surplus assets	12,400
Ending balance	78,480	$ 183,486
Incremental benefit payments	100,000
Actuarial net loss	$ 900
Payable maximum period to be considered current	12 months
Components of net periodic benefit cost [Abstract]
Net periodic benefit (income) cost	$ (3,013)	(465)	$ (2,914)
Weighted average assumptions in net periodic benefit calculations [Abstract]
Ultimate health care cost trend rate	4.10%
Minimum [Member]
Weighted average assumptions in net periodic benefit calculations [Abstract]
Annual assumed rate of increase in the per capita cost of covered benefits	4.30%
Maximum [Member]
Weighted average assumptions in net periodic benefit calculations [Abstract]
Annual assumed rate of increase in the per capita cost of covered benefits	8.70%
Pension Plan [Member]
Change in benefit obligation [Roll Forward]
Obligation at beginning of year	$ 182,164	166,739
Service cost	0	0	88
Interest cost	3,260	5,972	5,745
Actuarial loss (gain)	10,790	17,061
Plan amendments	0	0
Benefit payments	(9,214)	(9,883)
Curtailment	0	0
Settlement	(99,585)	0
Foreign currency translation adjustment	3,394	2,275
Obligation at end of year	90,809	182,164	166,739
Change in fair value of plan assets:
Beginning balance	183,486	164,603
Actual return on plan assets	13,313	26,734
Employer contributions	0	0
Benefit payments	(9,214)	(9,883)
Settlement	(99,585)	0
Surplus assets	12,386	0
Foreign currency translation adjustment	2,866	2,032
Ending balance	78,480	183,486	164,603
Funded (underfunded) status at end of year	(12,329)	1,322
Plan termination, termination costs	17,800
Plan termination, federal excise tax	6,200
Unrecognized net actuarial loss (gain)	26,476	36,195
Unrecognized prior service credit	0	0
Funded status of the plans recognized [Abstract]
Long-term asset	0	8,592
Current liability	0	0
Long-term liability	(12,329)	(7,270)
Total (underfunded) funded status	(12,329)	1,322
Components of net periodic benefit cost [Abstract]
Service cost	0	0	88
Interest cost	3,260	5,972	5,745
Expected return on plan assets	(5,704)	(8,103)	(9,522)
Amortization of net (gain) loss	2,305	1,950	1,151
Settlement charge	11,642	0	0
Net periodic benefit (income) cost	$ 11,503	$ (181)	$ (2,538)
Weighted average assumptions in benefit obligations calculations [Abstract]
Discount rate	1.40%	1.93%
Expected long-term return on plan assets	4.69%	3.84%
Rate of inflation	3.20%	3.20%
Weighted average assumptions in net periodic benefit calculations [Abstract]
Discount rate	1.93%	3.72%	3.22%
Expected long-term return on plan assets	3.84%	5.05%	5.27%
Rate of inflation	3.20%	3.40%	3.30%
Other Postretirement Benefits Plan [Member]
Change in benefit obligation [Roll Forward]
Obligation at beginning of year	$ 12,653	$ 14,382
Service cost	212	260	$ 235
Interest cost	430	609	447
Actuarial loss (gain)	422	(1,860)
Plan amendments	(26)	0
Benefit payments	(716)	(832)
Curtailment	(183)	0
Settlement	0	(198)
Foreign currency translation adjustment	(10)	292
Obligation at end of year	12,782	12,653	14,382
Change in fair value of plan assets:
Beginning balance	0	0
Actual return on plan assets	0	0
Employer contributions	716	832
Benefit payments	(716)	(832)
Settlement	0	0
Surplus assets	0	0
Foreign currency translation adjustment	0	0
Ending balance	0	0	0
Funded (underfunded) status at end of year	(12,782)	(12,653)
Unrecognized net actuarial loss (gain)	(1,187)	(1,609)
Unrecognized prior service credit	(2,401)	(5,485)
Funded status of the plans recognized [Abstract]
Long-term asset	0	0
Current liability	(948)	(1,013)
Long-term liability	(11,834)	(11,640)
Total (underfunded) funded status	(12,782)	(12,653)
Components of net periodic benefit cost [Abstract]
Service cost	212	260	235
Interest cost	430	609	447
Amortization of net (gain) loss	(193)	(88)	92
Amortization of prior service credit	(519)	(902)	(902)
Curtailment gain	(2,591)	0	0
Settlement charge	0	(2)	38
Net periodic benefit (income) cost	$ (2,661)	$ (123)	$ (90)
Weighted average assumptions in benefit obligations calculations [Abstract]
Discount rate	2.92%	3.70%
Rate of compensation increases	5.00%	5.00%
Weighted average assumptions in net periodic benefit calculations [Abstract]
Discount rate	3.70%	4.56%	3.89%
Rate of compensation increases	5.00%	5.00%	5.00%
Foreign Plan [Member] | Pension Plan [Member]
Change in fair value of plan assets:
Percent of above benefit obligation on company sponsored UK pension plan	100.00%	43.00%
Percent above plan assets on company sponsored UK pension plan	100.00%	39.00%