Business Segments (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 28, 2020	Mar. 30, 2019	Dec. 28, 2019
Segment Reporting, Revenue Reconciling Item [Line Items]
Net sales	$ 852,842	$ 835,104
Cost of sales and operating expenses	646,908	650,913
Gain (Loss) on Disposition of Assets	(61)	4,250
Selling, general and administrative expenses	96,193	85,003
Depreciation and amortization	84,671	79,164
Equity in net income of Diamond Green Diesel	97,820	24,277
Operating income	122,829	48,551
Equity in net income/(loss) of other unconsolidated subsidiaries	869	(504)
Total other expense	(19,307)	(23,133)
Income before income taxes	104,391	24,914
Segment Assets	5,377,779		$ 5,345,258
Feed Ingredients
Segment Reporting, Revenue Reconciling Item [Line Items]
Net sales	512,625	495,819
Cost of sales and operating expenses	388,453	386,859
Gross Margin	124,172	108,960
Gain (Loss) on Disposition of Assets	50	(4,391)
Selling, general and administrative expenses	53,947	48,831
Depreciation and amortization	53,521	49,369
Equity in net income of Diamond Green Diesel	0	0
Operating income	16,654	15,151
Equity in net income/(loss) of other unconsolidated subsidiaries	869	(504)
Segment income/(loss)	17,523	14,647
Segment Assets	2,613,292		2,653,363
Food Ingredients
Segment Reporting, Revenue Reconciling Item [Line Items]
Net sales	270,294	279,164
Cost of sales and operating expenses	205,430	214,004
Gross Margin	64,864	65,160
Gain (Loss) on Disposition of Assets	2	114
Selling, general and administrative expenses	25,476	21,887
Depreciation and amortization	20,305	19,511
Equity in net income of Diamond Green Diesel	0	0
Operating income	19,081	23,648
Equity in net income/(loss) of other unconsolidated subsidiaries	0	0
Segment income/(loss)	19,081	23,648
Segment Assets	1,314,436		1,345,526
Fuel Ingredients
Segment Reporting, Revenue Reconciling Item [Line Items]
Net sales	69,923	60,121
Cost of sales and operating expenses	53,025	50,050
Gross Margin	16,898	10,071
Gain (Loss) on Disposition of Assets	9	27
Selling, general and administrative expenses	1,654	(754)
Depreciation and amortization	8,092	7,798
Equity in net income of Diamond Green Diesel	97,820	24,277
Operating income	104,963	27,277
Equity in net income/(loss) of other unconsolidated subsidiaries	0	0
Segment income/(loss)	104,963	27,277
Segment Assets	1,181,241		1,087,701
Corporate
Segment Reporting, Revenue Reconciling Item [Line Items]
Net sales	0	0
Cost of sales and operating expenses	0	0
Gross Margin	0	0
Gain (Loss) on Disposition of Assets	0	0
Selling, general and administrative expenses	15,116	15,039
Depreciation and amortization	2,753	2,486
Equity in net income of Diamond Green Diesel	0	0
Operating income	(17,869)	(17,525)
Equity in net income/(loss) of other unconsolidated subsidiaries	0	0
Segment income/(loss)	(17,869)	(17,525)
Segment Assets	268,810		258,668
Total
Segment Reporting, Revenue Reconciling Item [Line Items]
Net sales	852,842	835,104
Cost of sales and operating expenses	646,908	650,913
Gross Margin	205,934	184,191
Gain (Loss) on Disposition of Assets	61	(4,250)
Selling, general and administrative expenses	96,193	85,003
Depreciation and amortization	84,671	79,164
Equity in net income of Diamond Green Diesel	97,820	24,277
Operating income	122,829	48,551
Equity in net income/(loss) of other unconsolidated subsidiaries	869	(504)
Segment income/(loss)	123,698	$ 48,047
Segment Assets	$ 5,377,779		$ 5,345,258