Guarantor Financial Information (Condensed Consolidated Statements of Operations) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 28, 2020	Mar. 30, 2019
Net sales	$ 852,842	$ 835,104
Costs and expenses:
Cost of sales and operating expenses	646,908	650,913
Loss (gain) on disposal of property, plant, equipment and other assets	61	(4,250)
Selling, general and administrative expenses	96,193	85,003
Depreciation and amortization	84,671	79,164
Total costs and expenses	827,833	810,830
Equity in net income of Diamond Green Diesel	97,820	24,277
Operating income	122,829	48,551
Interest expense	(19,090)	(19,876)
Foreign currency gain/(loss)	1,664	(732)
Other expense, net	(1,881)	(2,525)
Equity in net income/(loss) of other unconsolidated subsidiaries	869	(504)
Earnings in investments in subsidiaries	0	0
Income/(loss) before taxes	104,391	24,914
Income tax expense	18,300	5,274
Net income attributable to noncontrolling interests	(581)	(1,628)
Net income attributable to Darling	85,510	18,012
Parent [Member]
Net sales	180,919	160,230
Costs and expenses:
Cost of sales and operating expenses	144,142	128,324
Loss (gain) on disposal of property, plant, equipment and other assets	(38)	68
Selling, general and administrative expenses	48,074	47,423
Depreciation and amortization	17,272	14,373
Total costs and expenses	209,450	190,188
Equity in net income of Diamond Green Diesel	0	0
Operating income	(28,531)	(29,958)
Interest expense	(13,775)	(14,027)
Foreign currency gain/(loss)	(326)	(4)
Other expense, net	(1,540)	(1,567)
Equity in net income/(loss) of other unconsolidated subsidiaries	0	(891)
Earnings in investments in subsidiaries	121,939	54,627
Income/(loss) before taxes	77,767	8,180
Income tax expense	(7,743)	(9,832)
Net income attributable to noncontrolling interests	0	0
Net income attributable to Darling	85,510	18,012
Guarantors [Member]
Net sales	310,301	329,991
Costs and expenses:
Cost of sales and operating expenses	246,320	271,671
Loss (gain) on disposal of property, plant, equipment and other assets	63	(4,477)
Selling, general and administrative expenses	12,517	11,947
Depreciation and amortization	26,593	26,112
Total costs and expenses	285,493	305,253
Equity in net income of Diamond Green Diesel	0	0
Operating income	24,808	24,738
Interest expense	(58)	(32)
Foreign currency gain/(loss)	(24)	0
Other expense, net	(339)	(1,212)
Equity in net income/(loss) of other unconsolidated subsidiaries	0	0
Earnings in investments in subsidiaries	0	0
Income/(loss) before taxes	24,387	23,494
Income tax expense	4,275	4,973
Net income attributable to noncontrolling interests	0	0
Net income attributable to Darling	20,112	18,521
Non-guarantors [Member]
Net sales	405,025	403,911
Costs and expenses:
Cost of sales and operating expenses	299,849	309,946
Loss (gain) on disposal of property, plant, equipment and other assets	36	159
Selling, general and administrative expenses	35,602	25,633
Depreciation and amortization	40,806	38,679
Total costs and expenses	376,293	374,417
Equity in net income of Diamond Green Diesel	97,820	24,277
Operating income	126,552	53,771
Interest expense	(5,257)	(5,817)
Foreign currency gain/(loss)	2,014	(728)
Other expense, net	(2)	254
Equity in net income/(loss) of other unconsolidated subsidiaries	869	387
Earnings in investments in subsidiaries	0	0
Income/(loss) before taxes	124,176	47,867
Income tax expense	21,768	10,133
Net income attributable to noncontrolling interests	(581)	(1,628)
Net income attributable to Darling	101,827	36,106
Eliminations [Member]
Costs and expenses:
Equity in net income of Diamond Green Diesel	0	0
Eliminations [Member]
Net sales	(43,403)	(59,028)
Costs and expenses:
Cost of sales and operating expenses	(43,403)	(59,028)
Loss (gain) on disposal of property, plant, equipment and other assets	0	0
Selling, general and administrative expenses	0	0
Depreciation and amortization	0	0
Total costs and expenses	(43,403)	(59,028)
Operating income	0	0
Interest expense	0	0
Foreign currency gain/(loss)	0	0
Other expense, net	0	0
Equity in net income/(loss) of other unconsolidated subsidiaries	0	0
Earnings in investments in subsidiaries	(121,939)	(54,627)
Income/(loss) before taxes	(121,939)	(54,627)
Income tax expense	0	0
Net income attributable to noncontrolling interests	0	0
Net income attributable to Darling	$ (121,939)	$ (54,627)