Guarantor Financial Information Condensed Consolidated Statements of Operations (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended								12 Months Ended
	May 31, 2018	Dec. 28, 2019	Sep. 28, 2019	Jun. 29, 2019	Mar. 30, 2019	Dec. 29, 2018	Sep. 29, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 28, 2019	Dec. 29, 2018	Dec. 30, 2017
Net sales		$ 859,428	$ 842,049	$ 827,324	$ 835,104	$ 853,130	$ 812,576	$ 846,646	$ 875,374	$ 3,363,905	$ 3,387,726	$ 3,662,251
Costs and expenses:
Cost of sales and operating expenses										2,589,085	2,646,374	2,875,680
Loss/(gain) on sale of assets										(20,582)	709	(237)
Selling, general and administrative expense										358,523	309,264	343,502
Restructuring Costs and Asset Impairment Charges										0	14,965	0
Depreciation and amortization										325,510	321,192	302,100
Total costs and expenses										3,252,536	3,292,504	3,521,045
Equity In Income (Loss) from Subsidiary, before Tax										364,452	159,779	28,239
Operating income		293,287	59,859	74,124	48,551	73,738	15,556	36,754	128,953	475,821	255,001	169,445
Interest expense										(78,674)	(86,429)	(88,926)
Gain (Loss) on Extinguishment of Debt										(12,126)	(23,509)	0
Foreign currency losses										(1,311)	(6,431)	(6,898)
Gain (Loss) on Disposition of Business	$ 15,600									2,967	(12,545)	(885)
Other expense, net										(6,671)	(7,562)	(8,801)
Equity in net income of other unconsolidated subsidiaries										428	(550)	265
Earnings in investments in subsidiaries										0	0	0
Income from operations before income taxes		279,013	37,687	38,820	24,914	50,183	(6,540)	(27,455)	101,787	380,434	117,975	64,200
Income taxes (benefit)										59,467	12,031	(69,154)
Net income attributable to noncontrolling interests		(837)	(1,116)	(4,786)	(1,628)	(1,496)	(900)	(1,282)	(770)	(8,367)	(4,448)	(4,886)
Net income attributable to Darling		$ 242,609	$ 25,721	$ 26,258	$ 18,012	$ 40,648	$ (6,037)	$ (30,420)	$ 97,305	312,600	101,496	128,468
Parent Company [Member]
Net sales										652,708	541,499	545,699
Costs and expenses:
Cost of sales and operating expenses										515,286	422,028	429,983
Loss/(gain) on sale of assets										(403)	(86)	(302)
Selling, general and administrative expense										187,851	149,715	150,880
Restructuring Costs and Asset Impairment Charges											0
Depreciation and amortization										61,777	48,941	42,366
Total costs and expenses										764,511	620,598	622,927
Equity In Income (Loss) from Subsidiary, before Tax										0	0	0
Operating income										(111,803)	(79,099)	(77,228)
Interest expense										(56,240)	(56,832)	(55,336)
Gain (Loss) on Extinguishment of Debt										(12,126)	(15,635)
Foreign currency losses										(306)	(431)	(234)
Gain (Loss) on Disposition of Business										0	(15,583)	0
Other expense, net										(5,828)	(18,487)	(14,651)
Equity in net income of other unconsolidated subsidiaries										(2,425)	(2,622)	(1,847)
Earnings in investments in subsidiaries										471,827	270,943	438,580
Income from operations before income taxes										283,099	82,254	289,284
Income taxes (benefit)										(29,501)	(19,242)	160,816
Net income attributable to noncontrolling interests										0	0	0
Net income attributable to Darling										312,600	101,496	128,468
Guarantors [Member]
Net sales										1,305,464	1,338,376	1,464,920
Costs and expenses:
Cost of sales and operating expenses										1,078,247	1,080,420	1,198,528
Loss/(gain) on sale of assets										(7,356)	(184)	(257)
Selling, general and administrative expense										43,855	46,199	55,053
Restructuring Costs and Asset Impairment Charges											0
Depreciation and amortization										104,247	107,581	106,406
Total costs and expenses										1,218,993	1,234,016	1,359,730
Equity In Income (Loss) from Subsidiary, before Tax										0	0	0
Operating income										86,471	104,360	105,190
Interest expense										(167)	7,397	15,818
Gain (Loss) on Extinguishment of Debt										0	0
Foreign currency losses										4	(103)	114
Gain (Loss) on Disposition of Business										0	0	0
Other expense, net										(880)	(1,019)	37
Equity in net income of other unconsolidated subsidiaries										0	0	0
Earnings in investments in subsidiaries										0	0	0
Income from operations before income taxes										85,428	110,635	121,159
Income taxes (benefit)										13,354	11,282	(130,508)
Net income attributable to noncontrolling interests										0	0	0
Net income attributable to Darling										72,074	99,353	251,667
Non-guarantors [Member]
Net sales										1,637,861	1,738,427	1,893,304
Costs and expenses:
Cost of sales and operating expenses										1,227,680	1,374,502	1,488,841
Loss/(gain) on sale of assets										(12,823)	979	322
Selling, general and administrative expense										126,817	113,350	137,569
Restructuring Costs and Asset Impairment Charges											14,965
Depreciation and amortization										159,486	164,670	153,328
Total costs and expenses										1,501,160	1,668,466	1,780,060
Equity In Income (Loss) from Subsidiary, before Tax										364,452	159,779	28,239
Operating income										501,153	229,740	141,483
Interest expense										(22,267)	(36,994)	(49,408)
Gain (Loss) on Extinguishment of Debt										0	(7,874)
Foreign currency losses										(1,009)	(5,897)	(6,778)
Gain (Loss) on Disposition of Business										2,967	3,038	(885)
Other expense, net										37	11,944	5,813
Equity in net income of other unconsolidated subsidiaries										2,853	2,072	2,112
Earnings in investments in subsidiaries										0	0	0
Income from operations before income taxes										483,734	196,029	92,337
Income taxes (benefit)										75,614	19,991	(99,462)
Net income attributable to noncontrolling interests										(8,367)	(4,448)	(4,886)
Net income attributable to Darling										399,753	171,590	186,913
Consolidation, Eliminations [Member]
Costs and expenses:
Restructuring Costs and Asset Impairment Charges											0
Equity In Income (Loss) from Subsidiary, before Tax										0	0	0
Gain (Loss) on Extinguishment of Debt										0	0
Gain (Loss) on Disposition of Business										0	0	0
Consolidation, Eliminations [Member]
Net sales										(232,128)	(230,576)	(241,672)
Costs and expenses:
Cost of sales and operating expenses										(232,128)	(230,576)	(241,672)
Loss/(gain) on sale of assets										0	0	0
Selling, general and administrative expense										0	0	0
Depreciation and amortization										0	0	0
Total costs and expenses										(232,128)	(230,576)	(241,672)
Operating income										0	0	0
Interest expense										0	0	0
Foreign currency losses										0	0	0
Other expense, net										0	0	0
Equity in net income of other unconsolidated subsidiaries										0	0	0
Earnings in investments in subsidiaries										(471,827)	(270,943)	(438,580)
Income from operations before income taxes										(471,827)	(270,943)	(438,580)
Income taxes (benefit)										0	0	0
Net income attributable to noncontrolling interests										0	0	0
Net income attributable to Darling										$ (471,827)	$ (270,943)	$ (438,580)