Revenue Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 30, 2019	Mar. 31, 2018
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net sales	$ 835,104	$ 875,374
Feed Ingredients
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net sales	495,819	485,798
Food Ingredients
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net sales	279,164	305,520
Fuel Ingredients
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net sales	60,121	84,056
North America
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net sales	464,760	456,193
North America | Feed Ingredients
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net sales	410,237	390,376
North America | Food Ingredients
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net sales	48,813	44,277
North America | Fuel Ingredients
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net sales	5,710	21,540
Europe
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net sales	286,061	333,945
Europe | Feed Ingredients
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net sales	79,998	87,790
Europe | Food Ingredients
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net sales	151,652	183,639
Europe | Fuel Ingredients
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net sales	54,411	62,516
China
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net sales	49,889	49,590
China | Feed Ingredients
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net sales	2,952	5,678
China | Food Ingredients
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net sales	46,937	43,912
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	12,669	14,344
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	12,669	14,344
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	21,725	21,302
Other | Feed Ingredients
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net sales	2,632	1,954
Other | Food Ingredients
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net sales	19,093	19,348
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	180,014	188,371
Fats | Feed Ingredients
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net sales	144,876	143,552
Fats | Food Ingredients
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net sales	35,138	44,819
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	45,406	36,608
Used cooking oil | Feed Ingredients
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net sales	45,406	36,608
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	205,813	203,395
Proteins | Feed Ingredients
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net sales	205,813	203,395
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	45,656	46,751
Bakery | Feed Ingredients
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net sales	45,656	46,751
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	41,254	31,362
Other rendering | Feed Ingredients
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net sales	41,254	31,362
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	221,908	233,923
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	221,908	233,923
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	54,411	62,516
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	54,411	62,516
Biofuels
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net sales	5,710	21,540
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	5,710	21,540
Other
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net sales	34,932	50,908
Other | Feed Ingredients
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net sales	12,814	24,130
Other | Food Ingredients
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net sales	22,118	26,778
Other | Fuel Ingredients
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net sales	$ 0	$ 0