Business Segments (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
Segment Reporting Information [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
Cost of sales and operating expenses										2,688,815	2,589,085	2,646,374
Loss/(gain) on sale of assets										(426)	20,582	(709)
Selling, general and administrative expense										378,496	358,523	309,264
Restructuring Costs and Asset Impairment Charges		38,200								38,167	0	14,965
Depreciation and amortization										350,178	325,510	321,192
Equity In net income of Diamond Green Diesel										315,095	364,452	159,779
Segment operating income/(loss)		74,364	127,455	106,288	122,829	293,287	59,859	74,124	48,551	430,936	475,821	255,001
Equity in net income of other unconsolidated subsidiaries										3,193	428	(550)
Total other expense										(80,510)	(95,815)	(136,476)
Income before income taxes		56,370	$ 106,417	$ 86,441	$ 104,391	279,013	$ 37,687	$ 38,820	$ 24,914	353,619	380,434	117,975
Total assets		5,613,331				5,345,258				5,613,331	5,345,258
Capital expenditures:	[1]									280,115	359,498	321,896
Capital assets		18,400								18,400		31,600
Long-Lived Assets		4,626,337				4,427,970				4,626,337	4,427,970
North America
Segment Reporting Information [Line Items]
Net sales										1,960,503	1,889,573	1,817,001
Long-Lived Assets		3,056,047				2,991,537				3,056,047	2,991,537
Europe
Segment Reporting Information [Line Items]
Net sales										1,296,668	1,153,787	1,225,461
Long-Lived Assets		1,357,070				1,228,807				1,357,070	1,228,807
China
Segment Reporting Information [Line Items]
Net sales										202,093	194,625	210,657
Long-Lived Assets		127,549				124,874				127,549	124,874
South America
Segment Reporting Information [Line Items]
Net sales										38,238	51,168	53,206
Long-Lived Assets		74,720				73,477				74,720	73,477
Other
Segment Reporting Information [Line Items]
Long-Lived Assets		10,951				9,275				10,951	9,275
Feed Ingredients [Member]
Segment Reporting Information [Line Items]
Net sales										2,072,104	1,970,561	1,952,555
Cost of sales and operating expenses										1,544,524	1,519,596	1,497,973
Gross Margin										527,580	450,965	454,582
Loss/(gain) on sale of assets										19	(7,720)	725
Selling, general and administrative expense										209,748	200,487	176,722
Restructuring Costs and Asset Impairment Charges										0		0
Depreciation and amortization										221,187	203,456	194,292
Equity In net income of Diamond Green Diesel										0	0	0
Segment operating income/(loss)										96,626	54,742	82,843
Equity in net income of other unconsolidated subsidiaries										3,193	428	(550)
Segment income/(loss)										99,819	55,170	82,293
Total assets		2,708,922				2,653,363				2,708,922	2,653,363
Capital expenditures:										176,530	229,415	237,215
Feed Ingredients [Member] | North America
Segment Reporting Information [Line Items]
Net sales										1,694,705	1,635,382	1,586,930
Feed Ingredients [Member] | Europe
Segment Reporting Information [Line Items]
Net sales										352,748	309,097	329,341
Feed Ingredients [Member] | China
Segment Reporting Information [Line Items]
Net sales										13,676	16,342	28,288
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										1,185,701	1,119,085	1,139,126
Cost of sales and operating expenses										920,682	864,618	918,141
Gross Margin										265,019	254,467	220,985
Loss/(gain) on sale of assets										482	(13,175)	(282)
Selling, general and administrative expense										97,406	97,363	91,546
Restructuring Costs and Asset Impairment Charges										0		14,965
Depreciation and amortization										83,752	79,671	80,988
Equity In net income of Diamond Green Diesel										0	0	0
Segment operating income/(loss)										83,379	90,608	33,768
Equity in net income of other unconsolidated subsidiaries										0	0	0
Segment income/(loss)										83,379	90,608	33,768
Total assets		1,335,769				1,345,526				1,335,769	1,345,526
Capital expenditures:										68,250	85,501	51,659
Food Ingredients [Member] | North America
Segment Reporting Information [Line Items]
Net sales										244,929	214,623	181,213
Food Ingredients [Member] | Europe
Segment Reporting Information [Line Items]
Net sales										650,671	609,999	648,933
Food Ingredients [Member] | China
Segment Reporting Information [Line Items]
Net sales										188,417	178,283	182,369
Food Ingredients [Member] | South America
Segment Reporting Information [Line Items]
Net sales										38,238	51,168	53,206
Fuel Ingredients [Member]
Segment Reporting Information [Line Items]
Net sales										314,118	274,259	296,045
Cost of sales and operating expenses										223,609	204,871	230,260
Gross Margin										90,509	69,388	65,785
Loss/(gain) on sale of assets										(75)	313	266
Selling, general and administrative expense										16,014	2,762	(4,770)
Restructuring Costs and Asset Impairment Charges										38,167		0
Depreciation and amortization										34,218	31,946	34,981
Equity In net income of Diamond Green Diesel										315,095	364,452	159,779
Segment operating income/(loss)										317,280	398,819	195,087
Equity in net income of other unconsolidated subsidiaries										0	0	0
Segment income/(loss)										317,280	398,819	195,087
Total assets		1,160,132				1,087,701				1,160,132	1,087,701
Capital expenditures:										30,638	23,964	27,121
Fuel Ingredients [Member] | North America
Segment Reporting Information [Line Items]
Net sales										20,869	39,568	48,858
Fuel Ingredients [Member] | Europe
Segment Reporting Information [Line Items]
Net sales										293,249	234,691	247,187
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										55,328	57,911	45,766
Restructuring Costs and Asset Impairment Charges										0		0
Depreciation and amortization										11,021	10,437	10,931
Equity In net income of Diamond Green Diesel										0	0	0
Segment operating income/(loss)										(66,349)	(68,348)	(56,697)
Equity in net income of other unconsolidated subsidiaries										0	0	0
Segment income/(loss)										(66,349)	(68,348)	(56,697)
Total assets		408,508				258,668				408,508	258,668
Capital expenditures:										4,697	20,618	5,901
Operating Segments [Member]
Segment Reporting Information [Line Items]
Net sales										3,571,923	3,363,905	3,387,726
Cost of sales and operating expenses										2,688,815	2,589,085	2,646,374
Gross Margin										883,108	774,820	741,352
Loss/(gain) on sale of assets										426	(20,582)	709
Selling, general and administrative expense										378,496	358,523	309,264
Restructuring Costs and Asset Impairment Charges										38,167		14,965
Depreciation and amortization										350,178	325,510	321,192
Equity In net income of Diamond Green Diesel										315,095	364,452	159,779
Segment operating income/(loss)										430,936	475,821	255,001
Equity in net income of other unconsolidated subsidiaries										3,193	428	(550)
Segment income/(loss)										434,129	476,249	$ 254,451
Total assets		$ 5,613,331				$ 5,345,258				$ 5,613,331	$ 5,345,258

[1] Excludes capital assets acquired by acquisition in fiscal 2020 and fiscal 2018 of approximately $18.4 million and $31.6 million, respectively.