Business Segments (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 27, 2020	Jun. 29, 2019	Jun. 27, 2020	Jun. 29, 2019	Dec. 28, 2019
Segment Reporting, Revenue Reconciling Item [Line Items]
Net sales	$ 848,673	$ 827,324	$ 1,701,515	$ 1,662,428
Cost of sales and operating expenses	632,347	644,716	1,279,255	1,295,629
Gain (Loss) on Disposition of Assets	(27)	13,926	(88)	18,176
Selling, general and administrative expenses	90,193	81,017	186,386	166,020
Depreciation and amortization	83,310	79,486	167,981	158,650
Equity in net income of Diamond Green Diesel	63,492	38,093	161,312	62,370
Operating income	106,288	74,124	229,117	122,675
Equity in net income/(loss) of other unconsolidated subsidiaries	692	82	1,561	(422)
Total other expense	(20,539)	(35,386)	(39,846)	(58,519)
Income before income taxes	86,441	38,820	190,832	63,734
Segment Assets	5,327,154		5,327,154		$ 5,345,258
Feed Ingredients
Segment Reporting, Revenue Reconciling Item [Line Items]
Net sales	503,690	487,447	1,016,315	983,266
Cost of sales and operating expenses	367,902	376,955	756,355	763,814
Gross Margin	135,788	110,492	259,960	219,452
Gain (Loss) on Disposition of Assets	76	(524)	126	(4,914)
Selling, general and administrative expenses	50,484	46,465	104,431	95,296
Depreciation and amortization	52,683	48,720	106,204	98,089
Equity in net income of Diamond Green Diesel	0	0	0	0
Operating income	32,545	15,831	49,199	30,981
Equity in net income/(loss) of other unconsolidated subsidiaries	692	82	1,561	(422)
Segment income/(loss)	33,237	15,913	50,760	30,559
Segment Assets	2,600,884		2,600,884		2,653,363
Food Ingredients
Segment Reporting, Revenue Reconciling Item [Line Items]
Net sales	278,934	274,835	549,228	553,999
Cost of sales and operating expenses	220,159	214,444	425,589	428,448
Gross Margin	58,775	60,391	123,639	125,551
Gain (Loss) on Disposition of Assets	(48)	(13,379)	(46)	(13,265)
Selling, general and administrative expenses	22,564	23,431	48,040	45,318
Depreciation and amortization	19,972	19,861	40,277	39,372
Equity in net income of Diamond Green Diesel	0	0	0	0
Operating income	16,287	30,478	35,368	54,126
Equity in net income/(loss) of other unconsolidated subsidiaries	0	0	0	0
Segment income/(loss)	16,287	30,478	35,368	54,126
Segment Assets	1,325,739		1,325,739		1,345,526
Fuel Ingredients
Segment Reporting, Revenue Reconciling Item [Line Items]
Net sales	66,049	65,042	135,972	125,163
Cost of sales and operating expenses	44,286	53,317	97,311	103,367
Gross Margin	21,763	11,725	38,661	21,796
Gain (Loss) on Disposition of Assets	(1)	(23)	8	3
Selling, general and administrative expenses	3,953	425	5,607	(329)
Depreciation and amortization	7,980	8,362	16,072	16,160
Equity in net income of Diamond Green Diesel	63,492	38,093	161,312	62,370
Operating income	73,323	41,054	178,286	68,332
Equity in net income/(loss) of other unconsolidated subsidiaries	0	0	0	0
Segment income/(loss)	73,323	41,054	178,286	68,332
Segment Assets	1,090,623		1,090,623		1,087,701
Corporate
Segment Reporting, Revenue Reconciling Item [Line Items]
Net sales	0	0	0	0
Cost of sales and operating expenses	0	0	0	0
Gross Margin	0	0	0	0
Gain (Loss) on Disposition of Assets	0	0	0	0
Selling, general and administrative expenses	13,192	10,696	28,308	25,735
Depreciation and amortization	2,675	2,543	5,428	5,029
Equity in net income of Diamond Green Diesel	0	0	0	0
Operating income	(15,867)	(13,239)	(33,736)	(30,764)
Equity in net income/(loss) of other unconsolidated subsidiaries	0	0	0	0
Segment income/(loss)	(15,867)	(13,239)	(33,736)	(30,764)
Segment Assets	309,908		309,908		258,668
Total
Segment Reporting, Revenue Reconciling Item [Line Items]
Net sales	848,673	827,324	1,701,515	1,662,428
Cost of sales and operating expenses	632,347	644,716	1,279,255	1,295,629
Gross Margin	216,326	182,608	422,260	366,799
Gain (Loss) on Disposition of Assets	27	(13,926)	88	(18,176)
Selling, general and administrative expenses	90,193	81,017	186,386	166,020
Depreciation and amortization	83,310	79,486	167,981	158,650
Equity in net income of Diamond Green Diesel	63,492	38,093	161,312	62,370
Operating income	106,288	74,124	229,117	122,675
Equity in net income/(loss) of other unconsolidated subsidiaries	692	82	1,561	(422)
Segment income/(loss)	106,980	$ 74,206	230,678	$ 122,253
Segment Assets	$ 5,327,154		$ 5,327,154		$ 5,345,258