Income Taxes - Net Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 30, 2018	Dec. 31, 2017
Deferred tax assets
Retirement, postemployment and deferred compensation plans	$ 128,926	$ 140,657
Accruals for other employee benefits, compensation, insurance and other	22,722	16,883
Net operating losses	1,598	6,228
Other	23,400	31,686
Gross deferred tax assets	176,646	195,454
Deferred tax liabilities
Property, plant and equipment	38,268	31,043
Intangible assets	7,225	7,300
Other	2,722	4,065
Gross deferred tax liabilities	48,215	42,408
Net deferred tax asset	$ 128,431	$ 153,046
Valuation allowance, period for recoverability measurement	3 years