Business Segments (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
Segment Reporting Information [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
Cost of sales and operating expenses										2,589,085	2,646,374	2,875,680
Loss/(gain) on sale of assets										20,582	(709)	237
Selling, general and administrative expense										358,523	309,264	343,502
Restructuring Costs and Asset Impairment Charges										0	14,965	0
Depreciation and amortization										325,510	321,192	302,100
Equity In Income (Loss) from Subsidiary, before Tax										364,452	159,779	28,239
Segment operating income/(loss)		293,287	59,859	74,124	48,551	73,738	15,556	36,754	128,953	475,821	255,001	169,445
Equity in net income of other unconsolidated subsidiaries										428	(550)	265
Total other expense										(95,815)	(136,476)	(105,510)
Income before income taxes		279,013	$ 37,687	$ 38,820	$ 24,914	50,183	$ (6,540)	$ (27,455)	$ 101,787	380,434	117,975	64,200
Segment assets		5,345,258				4,889,354				5,345,258	4,889,354
Capital expenditures:	[1]									359,498	321,896	274,168
Capital assets		31,600								31,600
Long-Lived Assets		4,427,970				3,991,412				4,427,970	3,991,412
North America
Segment Reporting Information [Line Items]
Net sales										1,889,573	1,817,001	1,937,027
Long-Lived Assets		2,991,537				2,562,389				2,991,537	2,562,389
Europe
Segment Reporting Information [Line Items]
Net sales										1,153,787	1,225,461	1,372,750
Long-Lived Assets		1,228,807				1,219,084				1,228,807	1,219,084
China
Segment Reporting Information [Line Items]
Net sales										194,625	210,657	209,780
Long-Lived Assets		124,874				136,711				124,874	136,711
South America
Segment Reporting Information [Line Items]
Net sales										51,168	53,206	60,111
Long-Lived Assets		73,477				64,916				73,477	64,916
Other
Segment Reporting Information [Line Items]
Long-Lived Assets		9,275				8,312				9,275	8,312
Feed Ingredients [Member]
Segment Reporting Information [Line Items]
Net sales										1,970,561	1,952,555	2,239,492
Cost of sales and operating expenses										1,519,596	1,497,973	1,744,990
Gross Margin										450,965	454,582	494,502
Loss/(gain) on sale of assets										(7,720)	725	(358)
Selling, general and administrative expense										200,487	176,722	178,347
Restructuring Costs and Asset Impairment Charges											0
Depreciation and amortization										203,456	194,292	184,172
Equity In Income (Loss) from Subsidiary, before Tax										0	0	0
Segment operating income/(loss)										54,742	82,843	132,341
Equity in net income of other unconsolidated subsidiaries										428	(550)	265
Segment income/(loss)										55,170	82,293	132,606
Segment assets		2,653,363				2,566,106				2,653,363	2,566,106
Capital expenditures:										229,415	237,215	191,953
Feed Ingredients [Member] | North America
Segment Reporting Information [Line Items]
Net sales										1,635,382	1,586,930	1,696,081
Feed Ingredients [Member] | Europe
Segment Reporting Information [Line Items]
Net sales										309,097	329,341	503,786
Feed Ingredients [Member] | China
Segment Reporting Information [Line Items]
Net sales										16,342	28,288	32,103
Feed Ingredients [Member] | South America
Segment Reporting Information [Line Items]
Net sales										0	0	0
Food Ingredients [Member]
Segment Reporting Information [Line Items]
Net sales										1,119,085	1,139,126	1,156,976
Cost of sales and operating expenses										864,618	918,141	920,165
Gross Margin										254,467	220,985	236,811
Loss/(gain) on sale of assets										(13,175)	(282)	218
Selling, general and administrative expense										97,363	91,546	104,644
Restructuring Costs and Asset Impairment Charges											14,965
Depreciation and amortization										79,671	80,988	75,010
Equity In Income (Loss) from Subsidiary, before Tax										0	0	0
Segment operating income/(loss)										90,608	33,768	56,939
Equity in net income of other unconsolidated subsidiaries										0	0	0
Segment income/(loss)										90,608	33,768	56,939
Segment assets		1,345,526				1,401,291				1,345,526	1,401,291
Capital expenditures:										85,501	51,659	50,099
Food Ingredients [Member] | North America
Segment Reporting Information [Line Items]
Net sales										214,623	181,213	193,950
Food Ingredients [Member] | Europe
Segment Reporting Information [Line Items]
Net sales										609,999	648,933	650,177
Food Ingredients [Member] | China
Segment Reporting Information [Line Items]
Net sales										178,283	182,369	177,677
Food Ingredients [Member] | South America
Segment Reporting Information [Line Items]
Net sales										51,168	53,206	60,111
Fuel Ingredients [Member]
Segment Reporting Information [Line Items]
Net sales										274,259	296,045	265,783
Cost of sales and operating expenses										204,871	230,260	210,525
Gross Margin										69,388	65,785	55,258
Loss/(gain) on sale of assets										313	266	(97)
Selling, general and administrative expense										2,762	(4,770)	10,355
Restructuring Costs and Asset Impairment Charges											0
Depreciation and amortization										31,946	34,981	31,019
Equity In Income (Loss) from Subsidiary, before Tax										364,452	159,779	28,239
Segment operating income/(loss)										398,819	195,087	42,220
Equity in net income of other unconsolidated subsidiaries										0	0	0
Segment income/(loss)										398,819	195,087	42,220
Segment assets		1,087,701				761,817				1,087,701	761,817
Capital expenditures:										23,964	27,121	24,707
Fuel Ingredients [Member] | North America
Segment Reporting Information [Line Items]
Net sales										39,568	48,858	46,996
Fuel Ingredients [Member] | Europe
Segment Reporting Information [Line Items]
Net sales										234,691	247,187	218,787
Fuel Ingredients [Member] | China
Segment Reporting Information [Line Items]
Net sales										0	0	0
Fuel Ingredients [Member] | South America
Segment Reporting Information [Line Items]
Net sales										0	0	0
Corporate Segment [Member]
Segment Reporting Information [Line Items]
Net sales										0	0	0
Cost of sales and operating expenses										0	0	0
Gross Margin										0	0	0
Loss/(gain) on sale of assets										0	0	0
Selling, general and administrative expense										57,911	45,766	50,156
Restructuring Costs and Asset Impairment Charges											0
Depreciation and amortization										10,437	10,931	11,899
Equity In Income (Loss) from Subsidiary, before Tax										0	0	0
Segment operating income/(loss)										(68,348)	(56,697)	(62,055)
Equity in net income of other unconsolidated subsidiaries										0	0	0
Segment income/(loss)										(68,348)	(56,697)	(62,055)
Segment assets		258,668				160,140				258,668	160,140
Capital expenditures:										20,618	5,901	7,409
Operating Segments [Member]
Segment Reporting Information [Line Items]
Net sales										3,363,905	3,387,726	3,662,251
Cost of sales and operating expenses										2,589,085	2,646,374	2,875,680
Gross Margin										774,820	741,352	786,571
Loss/(gain) on sale of assets										(20,582)	709	(237)
Selling, general and administrative expense										358,523	309,264	343,502
Restructuring Costs and Asset Impairment Charges											14,965
Depreciation and amortization										325,510	321,192	302,100
Equity In Income (Loss) from Subsidiary, before Tax										364,452	159,779	28,239
Segment operating income/(loss)										475,821	255,001	169,445
Equity in net income of other unconsolidated subsidiaries										428	(550)	265
Segment income/(loss)										476,249	254,451	$ 169,710
Segment assets		$ 5,345,258				$ 4,889,354				$ 5,345,258	$ 4,889,354

[1] Excludes capital assets acquired by acquisition in fiscal 2018 of approximately $31.6 million and excludes immaterial capital assets acquired by acquisition in fiscal 2017.