Income Taxes - Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 28, 2019	Dec. 29, 2018
Deferred tax assets:
Loss contingency reserves	$ 11,193	$ 9,007
Employee benefits	12,236	10,791
Pension liability	13,049	12,882
Intangible assets amortization, including taxable goodwill	1,485	1,566
Interest expense carryforwards	12,361	16,871
Tax loss carryforwards	80,195	103,618
Tax credit carryforwards	5,653	5,108
Operating lease liabilities	33,549	0
Inventory	5,185	8,583
Accrued liabilities and other	13,677	12,291
Total gross deferred tax assets	188,583	180,717
Less valuation allowance	(24,759)	(27,942)
Net deferred tax assets	163,824	152,775
Deferred tax liabilities:
Intangible assets amortization, including taxable goodwill	(157,332)	(152,841)
Property, plant and equipment depreciation	(144,911)	(164,011)
Investment in DGD Joint Venture	(54,287)	(44,857)
Operating lease assets	(32,233)	0
Tax on unremitted foreign earnings	(6,139)	(5,648)
Other	(2,459)	(1,500)
Total gross deferred tax liabilities	(397,361)	(368,857)
Net deferred tax liability	(233,537)	(216,082)
Non-current deferred tax asset	14,394	14,981
Non-current deferred tax liability	$ (247,931)	$ (231,063)