Revenue Disaggregation of revenues (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Jan. 02, 2021	Sep. 26, 2020	Jun. 27, 2020	Mar. 28, 2020	Dec. 28, 2019	Sep. 28, 2019	Jun. 29, 2019	Mar. 30, 2019	Jan. 02, 2021	Dec. 28, 2019	Dec. 29, 2018
Disaggregation of Revenue [Line Items]
Net sales	$ 1,019,839	$ 850,569	$ 848,673	$ 852,842	$ 859,428	$ 842,049	$ 827,324	$ 835,104	$ 3,571,923	$ 3,363,905	$ 3,387,726
North America
Disaggregation of Revenue [Line Items]
Net sales									1,960,503	1,889,573	1,817,001
Europe
Disaggregation of Revenue [Line Items]
Net sales									1,296,668	1,153,787	1,225,461
China
Disaggregation of Revenue [Line Items]
Net sales									202,093	194,625	210,657
South America
Disaggregation of Revenue [Line Items]
Net sales									38,238	51,168	53,206
Other Geographical Areas [Member]
Disaggregation of Revenue [Line Items]
Net sales									74,421	74,752	81,401
Fats [Member]
Disaggregation of Revenue [Line Items]
Net sales									804,737	718,234	728,605
Used Cooking Oil [Member]
Disaggregation of Revenue [Line Items]
Net sales									176,691	185,705	166,634
Proteins [Member]
Disaggregation of Revenue [Line Items]
Net sales									830,195	791,284	842,878
Bakery [Member]
Disaggregation of Revenue [Line Items]
Net sales									183,759	191,551	180,227
Other Rendering [Member]
Disaggregation of Revenue [Line Items]
Net sales									178,601	167,870	129,273
Food Ingredients, Products and Services [Member]
Disaggregation of Revenue [Line Items]
Net sales									947,928	894,761	886,042
Bioenergy [Member]
Disaggregation of Revenue [Line Items]
Net sales									293,249	234,691	247,187
Biofuels [Member]
Disaggregation of Revenue [Line Items]
Net sales									20,869	39,568	48,858
Other, Products And Services [Member]
Disaggregation of Revenue [Line Items]
Net sales									135,894	140,241	158,022
Food Ingredients [Member]
Disaggregation of Revenue [Line Items]
Net sales									1,185,701	1,119,085	1,139,126
Food Ingredients [Member] | North America
Disaggregation of Revenue [Line Items]
Net sales									244,929	214,623	181,213
Food Ingredients [Member] | Europe
Disaggregation of Revenue [Line Items]
Net sales									650,671	609,999	648,933
Food Ingredients [Member] | China
Disaggregation of Revenue [Line Items]
Net sales									188,417	178,283	182,369
Food Ingredients [Member] | South America
Disaggregation of Revenue [Line Items]
Net sales									38,238	51,168	53,206
Food Ingredients [Member] | Other Geographical Areas [Member]
Disaggregation of Revenue [Line Items]
Net sales									63,446	65,012	73,405
Food Ingredients [Member] | Fats [Member]
Disaggregation of Revenue [Line Items]
Net sales									142,963	133,898	163,815
Food Ingredients [Member] | Used Cooking Oil [Member]
Disaggregation of Revenue [Line Items]
Net sales									0	0	0
Food Ingredients [Member] | Proteins [Member]
Disaggregation of Revenue [Line Items]
Net sales									0	0	0
Food Ingredients [Member] | Bakery [Member]
Disaggregation of Revenue [Line Items]
Net sales									0	0	0
Food Ingredients [Member] | Other Rendering [Member]
Disaggregation of Revenue [Line Items]
Net sales									0	0	0
Food Ingredients [Member] | Food Ingredients, Products and Services [Member]
Disaggregation of Revenue [Line Items]
Net sales									947,928	894,761	886,042
Food Ingredients [Member] | Bioenergy [Member]
Disaggregation of Revenue [Line Items]
Net sales									0	0	0
Food Ingredients [Member] | Biofuels [Member]
Disaggregation of Revenue [Line Items]
Net sales									0	0	0
Food Ingredients [Member] | Other, Products And Services [Member]
Disaggregation of Revenue [Line Items]
Net sales									94,810	90,426	89,269
Fuel Ingredients [Member]
Disaggregation of Revenue [Line Items]
Net sales									314,118	274,259	296,045
Fuel Ingredients [Member] | North America
Disaggregation of Revenue [Line Items]
Net sales									20,869	39,568	48,858
Fuel Ingredients [Member] | Europe
Disaggregation of Revenue [Line Items]
Net sales									293,249	234,691	247,187
Fuel Ingredients [Member] | China
Disaggregation of Revenue [Line Items]
Net sales									0	0	0
Fuel Ingredients [Member] | South America
Disaggregation of Revenue [Line Items]
Net sales									0	0	0
Fuel Ingredients [Member] | Other Geographical Areas [Member]
Disaggregation of Revenue [Line Items]
Net sales									0	0	0
Fuel Ingredients [Member] | Fats [Member]
Disaggregation of Revenue [Line Items]
Net sales									0	0	0
Fuel Ingredients [Member] | Used Cooking Oil [Member]
Disaggregation of Revenue [Line Items]
Net sales									0	0	0
Fuel Ingredients [Member] | Proteins [Member]
Disaggregation of Revenue [Line Items]
Net sales									0	0	0
Fuel Ingredients [Member] | Bakery [Member]
Disaggregation of Revenue [Line Items]
Net sales									0	0	0
Fuel Ingredients [Member] | Other Rendering [Member]
Disaggregation of Revenue [Line Items]
Net sales									0	0	0
Fuel Ingredients [Member] | Food Ingredients, Products and Services [Member]
Disaggregation of Revenue [Line Items]
Net sales									0	0	0
Fuel Ingredients [Member] | Bioenergy [Member]
Disaggregation of Revenue [Line Items]
Net sales									293,249	234,691	247,187
Fuel Ingredients [Member] | Biofuels [Member]
Disaggregation of Revenue [Line Items]
Net sales									20,869	39,568	48,858
Fuel Ingredients [Member] | Other, Products And Services [Member]
Disaggregation of Revenue [Line Items]
Net sales									0	0	0
Feed Ingredients [Member]
Disaggregation of Revenue [Line Items]
Net sales									2,072,104	1,970,561	1,952,555
Feed Ingredients [Member] | North America
Disaggregation of Revenue [Line Items]
Net sales									1,694,705	1,635,382	1,586,930
Feed Ingredients [Member] | Europe
Disaggregation of Revenue [Line Items]
Net sales									352,748	309,097	329,341
Feed Ingredients [Member] | China
Disaggregation of Revenue [Line Items]
Net sales									13,676	16,342	28,288
Feed Ingredients [Member] | South America
Disaggregation of Revenue [Line Items]
Net sales									0	0	0
Feed Ingredients [Member] | Other Geographical Areas [Member]
Disaggregation of Revenue [Line Items]
Net sales									10,975	9,740	7,996
Feed Ingredients [Member] | Fats [Member]
Disaggregation of Revenue [Line Items]
Net sales									661,774	584,336	564,790
Feed Ingredients [Member] | Used Cooking Oil [Member]
Disaggregation of Revenue [Line Items]
Net sales									176,691	185,705	166,634
Feed Ingredients [Member] | Proteins [Member]
Disaggregation of Revenue [Line Items]
Net sales									830,195	791,284	842,878
Feed Ingredients [Member] | Bakery [Member]
Disaggregation of Revenue [Line Items]
Net sales									183,759	191,551	180,227
Feed Ingredients [Member] | Other Rendering [Member]
Disaggregation of Revenue [Line Items]
Net sales									178,601	167,870	129,273
Feed Ingredients [Member] | Food Ingredients, Products and Services [Member]
Disaggregation of Revenue [Line Items]
Net sales									0	0	0
Feed Ingredients [Member] | Bioenergy [Member]
Disaggregation of Revenue [Line Items]
Net sales									0	0	0
Feed Ingredients [Member] | Biofuels [Member]
Disaggregation of Revenue [Line Items]
Net sales									0	0	0
Feed Ingredients [Member] | Other, Products And Services [Member]
Disaggregation of Revenue [Line Items]
Net sales									$ 41,084	$ 49,815	$ 68,753