Revenue Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 28, 2020	Mar. 30, 2019
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net sales	$ 852,842	$ 835,104
Feed Ingredients
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net sales	512,625	495,819
Food Ingredients
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net sales	270,294	279,164
Fuel Ingredients
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net sales	69,923	60,121
North America
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net sales	479,278	464,760
North America | Feed Ingredients
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net sales	427,463	410,237
North America | Food Ingredients
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net sales	46,415	48,813
North America | Fuel Ingredients
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net sales	5,400	5,710
Europe
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net sales	303,553	286,061
Europe | Feed Ingredients
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net sales	80,443	79,998
Europe | Food Ingredients
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net sales	158,587	151,652
Europe | Fuel Ingredients
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net sales	64,523	54,411
China
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net sales	42,379	49,889
China | Feed Ingredients
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net sales	2,423	2,952
China | Food Ingredients
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net sales	39,956	46,937
China | Fuel Ingredients
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net sales	0	0
South America
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net sales	10,586	12,669
South America | Feed Ingredients
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net sales	0	0
South America | Food Ingredients
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net sales	10,586	12,669
South America | Fuel Ingredients
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net sales	0	0
Other
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net sales	17,046	21,725
Other | Feed Ingredients
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net sales	2,296	2,632
Other | Food Ingredients
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net sales	14,750	19,093
Other | Fuel Ingredients
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net sales	0	0
Fats
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net sales	196,760	180,014
Fats | Feed Ingredients
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net sales	163,284	144,876
Fats | Food Ingredients
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net sales	33,476	35,138
Fats | Fuel Ingredients
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net sales	0	0
Used cooking oil
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net sales	47,608	45,406
Used cooking oil | Feed Ingredients
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net sales	47,608	45,406
Used cooking oil | Food Ingredients
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net sales	0	0
Used cooking oil | Fuel Ingredients
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net sales	0	0
Proteins
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net sales	195,980	205,813
Proteins | Feed Ingredients
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net sales	195,980	205,813
Proteins | Food Ingredients
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net sales	0	0
Proteins | Fuel Ingredients
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net sales	0	0
Bakery
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net sales	47,101	45,656
Bakery | Feed Ingredients
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net sales	47,101	45,656
Bakery | Food Ingredients
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net sales	0	0
Bakery | Fuel Ingredients
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net sales	0	0
Other rendering
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net sales	47,164	41,254
Other rendering | Feed Ingredients
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net sales	47,164	41,254
Other rendering | Food Ingredients
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net sales	0	0
Other rendering | Fuel Ingredients
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net sales	0	0
Food ingredients
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net sales	214,793	221,908
Food ingredients | Feed Ingredients
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net sales	0	0
Food ingredients | Food Ingredients
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net sales	214,793	221,908
Food ingredients | Fuel Ingredients
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net sales	0	0
Bioenergy
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net sales	64,523	54,411
Bioenergy | Feed Ingredients
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net sales	0	0
Bioenergy | Food Ingredients
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net sales	0	0
Bioenergy | Fuel Ingredients
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net sales	64,523	54,411
Biofuels
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net sales	5,400	5,710
Biofuels | Feed Ingredients
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net sales	0	0
Biofuels | Food Ingredients
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net sales	0	0
Biofuels | Fuel Ingredients
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net sales	5,400	5,710
Other
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net sales	33,513	34,932
Other | Feed Ingredients
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net sales	11,488	12,814
Other | Food Ingredients
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net sales	22,025	22,118
Other | Fuel Ingredients
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net sales	$ 0	$ 0