Comprehensive Income AOCI (Details) $ in Thousands	12 Months Ended
	Jan. 02, 2021 USD ($)
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Accumulated Other Comprehensive Income/(loss) January 2, 2016, attributable to Darling, net of tax	$ (321,847)
Other comprehensive gain before reclassifications	74,265
Amounts reclassified from accumulated other comprehensive income/(loss)	(5,967)
Reclassification of tax effect	(4,800)
Net current-period other comprehensive income	68,298
Noncontrolling interest	(1,116)
Accumulated Other Comprehensive Income/(loss) December 31, 2016, attributable to Darling, net of tax	(252,433)
Foreign Currency Translation
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Accumulated Other Comprehensive Income/(loss) January 2, 2016, attributable to Darling, net of tax	(282,338)
Other comprehensive gain before reclassifications	70,320
Amounts reclassified from accumulated other comprehensive income/(loss)	0
Net current-period other comprehensive income	70,320
Noncontrolling interest	(1,116)
Accumulated Other Comprehensive Income/(loss) December 31, 2016, attributable to Darling, net of tax	(210,902)
Derivative Instruments
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Accumulated Other Comprehensive Income/(loss) January 2, 2016, attributable to Darling, net of tax	(5,505)
Other comprehensive gain before reclassifications	10,857
Amounts reclassified from accumulated other comprehensive income/(loss)	(8,566)
Net current-period other comprehensive income	2,291
Noncontrolling interest	0
Accumulated Other Comprehensive Income/(loss) December 31, 2016, attributable to Darling, net of tax	(3,214)
Defined Benefit Pension Plans
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Accumulated Other Comprehensive Income/(loss) January 2, 2016, attributable to Darling, net of tax	(34,004)
Other comprehensive gain before reclassifications	(6,912)
Amounts reclassified from accumulated other comprehensive income/(loss)	2,599
Net current-period other comprehensive income	(4,313)
Noncontrolling interest	0
Accumulated Other Comprehensive Income/(loss) December 31, 2016, attributable to Darling, net of tax	$ (38,317)