Pension, Postretirement and Postemployment Benefits (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2017 USD ($)	Dec. 25, 2016 USD ($)	Dec. 27, 2015 USD ($)	Dec. 31, 2017 USD ($)	Dec. 25, 2016 USD ($)
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Pension expense	$ 45,900	$ 45,200	$ 36,000
Pension expense related to defined contribution plans	36,000	33,300	26,600
Defined benefit plan, number of major plans which principally cover non-union employees				2
Assumptions used to determine year-end pension and postretirement benefit obligations [Abstract]
Defined benefit plan, number of major plans that are funded				1
Reconciliation of Funded Status [Abstract]
Expected amortization of unrecognized net losses in next fiscal year				$ 8,445
Pension [Member]
Assumptions used to determine year-end pension and postretirement benefit obligations [Abstract]
Weighted average discount rate				3.71%	4.22%
Change in Projected Benefit Obligation [Roll Forward]
Service cost	1,290	2,100	1,918
Interest cost	15,303	16,106	15,683
Pension [Member] | International Plans[Member]
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Pension expense	3,473	1,533	2,769
Reconciliation of Funded Status [Abstract]
Expected amortization of unrecognized net losses in next fiscal year				$ 1,026
Expected amortization of unrecognized prior service cost in next fiscal year				(36)
Pension [Member] | United States [Member]
Change in Projected Benefit Obligation [Roll Forward]
Projected benefit obligation - beginning	372,824	361,060
Service cost	1,290	2,100
Interest cost	15,303	16,106
Actuarial (gain) loss	27,670	17,353
Curtailment	0	0
Benefits paid	22,579	22,508
Expenses paid	1,141	1,287
Projected benefit obligation - ending	393,367	372,824	361,060
Accumulated benefit obligation - ending				393,367	$ 372,824
Change in Plan Assets [Roll Forward]
Fair value of plan assets - beginning	309,380	259,329
Actual return on plan assets	44,562	8,961
Employer contribution	52,767	64,885
Benefits paid	(22,579)	(22,508)
Expenses paid	(1,141)	(1,287)
Fair value of plan assets - ending	382,989	309,380	259,329
Reconciliation of Funded Status [Abstract]
Projected benefit obligation	(393,367)	(361,060)	(361,060)	(393,367)	(372,824)
Fair value of plan assets	$ 309,380	$ 309,380	259,329	382,989	309,380
Funded status				(10,378)	(63,444)
Unrecognized net loss (gain)				132,088	138,529
Unrecognized prior service cost				0	0
Net amount recognized				121,710	75,085
Accrued liabilities				(2,448)	(2,553)
Other liabilities				(7,930)	(60,891)
Accumulated other comprehensive earnings (loss)				132,088	138,529
Pension [Member] | United States [Member] | Funded [Member]
Assumptions used to determine year-end pension and postretirement benefit obligations [Abstract]
Projected benefit obligations in excess of the fair value of the plans' assets				(25,603)	28,340
Pension [Member] | United States [Member] | Unfunded [Member]
Assumptions used to determine year-end pension and postretirement benefit obligations [Abstract]
Projected benefit obligations in excess of the fair value of the plans' assets				$ 35,981	$ 35,104
Postretirement [Member]
Assumptions used to determine year-end pension and postretirement benefit obligations [Abstract]
Weighted average discount rate				3.74%	4.26%
Health care cost trend rate assumed for next year	6.50%	7.00%
Rate to which the cost trend rate is assumed to decline (ultimate trend rate)	5.00%	5.00%
Year that the rate reaches the ultimate trend	2024	2021
Change in Projected Benefit Obligation [Roll Forward]
Service cost	$ 691	$ 532	567
Interest cost	1,179	1,175	1,154
Postretirement [Member] | United States [Member]
Change in Projected Benefit Obligation [Roll Forward]
Projected benefit obligation - beginning	28,484	26,247
Service cost	691	532
Interest cost	1,179	1,175
Actuarial (gain) loss	3,432	2,380
Curtailment	0	0
Benefits paid	1,633	1,850
Expenses paid	0	0
Projected benefit obligation - ending	32,153	28,484	26,247
Accumulated benefit obligation - ending				$ 32,153	$ 28,484
Change in Plan Assets [Roll Forward]
Fair value of plan assets - beginning	0	0
Actual return on plan assets	0	0
Employer contribution	0	0
Benefits paid	0	0
Expenses paid	0	0
Fair value of plan assets - ending	0	0	0
Reconciliation of Funded Status [Abstract]
Projected benefit obligation	(28,484)	(28,484)	(26,247)	(32,153)	(28,484)
Fair value of plan assets	$ 0	$ 0	$ 0	0	0
Funded status				(32,153)	(28,484)
Unrecognized net loss (gain)				5,853	2,420
Unrecognized prior service cost				0	0
Net amount recognized				(26,300)	(26,064)
Accrued liabilities				(1,630)	(1,599)
Other liabilities				(30,523)	(26,885)
Accumulated other comprehensive earnings (loss)				$ 5,853	$ 2,420