Revenue Disaggregation of revenues (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 28, 2019	Sep. 28, 2019	Jun. 29, 2019	Mar. 30, 2019	Dec. 29, 2018	Sep. 29, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 28, 2019	Dec. 29, 2018	Dec. 30, 2017
Disaggregation of Revenue [Line Items]
Net sales	$ 859,428	$ 842,049	$ 827,324	$ 835,104	$ 853,130	$ 812,576	$ 846,646	$ 875,374	$ 3,363,905	$ 3,387,726	$ 3,662,251
North America
Disaggregation of Revenue [Line Items]
Net sales									1,889,573	1,817,001	1,937,027
Europe
Disaggregation of Revenue [Line Items]
Net sales									1,153,787	1,225,461	1,372,750
China
Disaggregation of Revenue [Line Items]
Net sales									194,625	210,657	209,780
South America
Disaggregation of Revenue [Line Items]
Net sales									51,168	53,206	60,111
Other Geographical Areas [Member]
Disaggregation of Revenue [Line Items]
Net sales									74,752	81,401	82,583
Fats [Member]
Disaggregation of Revenue [Line Items]
Net sales									718,234	728,605	832,047
Used Cooking Oil [Member]
Disaggregation of Revenue [Line Items]
Net sales									185,705	166,634	185,516
Proteins [Member]
Disaggregation of Revenue [Line Items]
Net sales									791,284	842,878	816,060
Bakery [Member]
Disaggregation of Revenue [Line Items]
Net sales									191,551	180,227	209,801
Other Rendering [Member]
Disaggregation of Revenue [Line Items]
Net sales									167,870	129,273	286,183
Food Ingredients, Products and Services [Member]
Disaggregation of Revenue [Line Items]
Net sales									894,761	886,042	880,128
Bioenergy [Member]
Disaggregation of Revenue [Line Items]
Net sales									234,691	247,187	218,787
Biofuels [Member]
Disaggregation of Revenue [Line Items]
Net sales									39,568	48,858	46,996
Other, Products And Services [Member]
Disaggregation of Revenue [Line Items]
Net sales									140,241	158,022	186,733
Food Ingredients [Member]
Disaggregation of Revenue [Line Items]
Net sales									1,119,085	1,139,126	1,156,976
Food Ingredients [Member] | North America
Disaggregation of Revenue [Line Items]
Net sales									214,623	181,213	193,950
Food Ingredients [Member] | Europe
Disaggregation of Revenue [Line Items]
Net sales									609,999	648,933	650,177
Food Ingredients [Member] | China
Disaggregation of Revenue [Line Items]
Net sales									178,283	182,369	177,677
Food Ingredients [Member] | South America
Disaggregation of Revenue [Line Items]
Net sales									51,168	53,206	60,111
Food Ingredients [Member] | Other Geographical Areas [Member]
Disaggregation of Revenue [Line Items]
Net sales									65,012	73,405	75,061
Food Ingredients [Member] | Fats [Member]
Disaggregation of Revenue [Line Items]
Net sales									133,898	163,815	183,719
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									894,761	886,042	880,128
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									90,426	89,269	93,129
Fuel Ingredients [Member]
Disaggregation of Revenue [Line Items]
Net sales									274,259	296,045	265,783
Fuel Ingredients [Member] | North America
Disaggregation of Revenue [Line Items]
Net sales									39,568	48,858	46,996
Fuel Ingredients [Member] | Europe
Disaggregation of Revenue [Line Items]
Net sales									234,691	247,187	218,787
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									234,691	247,187	218,787
Fuel Ingredients [Member] | Biofuels [Member]
Disaggregation of Revenue [Line Items]
Net sales									39,568	48,858	46,996
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									1,970,561	1,952,555	2,239,492
Feed Ingredients [Member] | North America
Disaggregation of Revenue [Line Items]
Net sales									1,635,382	1,586,930	1,696,081
Feed Ingredients [Member] | Europe
Disaggregation of Revenue [Line Items]
Net sales									309,097	329,341	503,786
Feed Ingredients [Member] | China
Disaggregation of Revenue [Line Items]
Net sales									16,342	28,288	32,103
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									9,740	7,996	7,522
Feed Ingredients [Member] | Fats [Member]
Disaggregation of Revenue [Line Items]
Net sales									584,336	564,790	648,328
Feed Ingredients [Member] | Used Cooking Oil [Member]
Disaggregation of Revenue [Line Items]
Net sales									185,705	166,634	185,516
Feed Ingredients [Member] | Proteins [Member]
Disaggregation of Revenue [Line Items]
Net sales									791,284	842,878	816,060
Feed Ingredients [Member] | Bakery [Member]
Disaggregation of Revenue [Line Items]
Net sales									191,551	180,227	209,801
Feed Ingredients [Member] | Other Rendering [Member]
Disaggregation of Revenue [Line Items]
Net sales									167,870	129,273	286,183
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									$ 49,815	$ 68,753	93,604
Calculated under Revenue Guidance in Effect before Topic 606 [Member]
Disaggregation of Revenue [Line Items]
Revenue, Modified Retrospective Basis Effect											$ 160,000