Quarterly Financial Data (Details) - USD ($) $ / shares in Units, $ 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	Dec. 30, 2017
Investment [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
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
Income from operations 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
Net income	46,139	101,605	66,495	86,091	243,446	26,837	31,044	19,640	300,330	320,967	105,944
Net income attributable to noncontrolling interests	(1,394)	(480)	(1,056)	(581)	(837)	(1,116)	(4,786)	(1,628)	(3,511)	(8,367)	(4,448)
Net income attributable to Darling	$ 44,745	$ 101,125	$ 65,439	$ 85,510	$ 242,609	$ 25,721	$ 26,258	$ 18,012	$ 296,819	$ 312,600	$ 101,496
Basic (in dollars per share)	$ 0.28	$ 0.62	$ 0.40	$ 0.52	$ 1.48	$ 0.16	$ 0.16	$ 0.11	$ 1.83	$ 1.90	$ 0.62
Diluted (in dollars per share)	$ 0.27	$ 0.61	$ 0.39	$ 0.51	$ 1.44	$ 0.15	$ 0.16	$ 0.11	$ 1.78	$ 1.86	$ 0.60
Cost of sales and operating expenses									$ 2,688,815	$ 2,589,085	$ 2,646,374
Restructuring Costs and Asset Impairment Charges	$ 38,200								38,167	0	14,965
Diamond Green Diesel Holdings LLC Joint Venture [Member]
Investment [Line Items]
Income Tax Credits and Adjustments	$ 234,400								$ 287,900	$ 274,700	$ 155,900	$ 160,400