Segment Information Reconciliation of Profit from Segments to Consolidated (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Jan. 03, 2021	Sep. 27, 2020	Jun. 28, 2020	Mar. 29, 2020	Dec. 29, 2019	Sep. 29, 2019	Jun. 30, 2019	Mar. 31, 2019	Jan. 03, 2021	Dec. 29, 2019	Dec. 30, 2018
Segment Reporting, Reconciling Item for Profit from Segment to Consolidated
Segment profit	$ 78,567	$ 81,348	$ 60,661	$ 48,732	$ 36,717	$ 79,023	$ 80,573	$ 66,266	$ 269,308	$ 262,579	$ 249,892
Advertising funds surplus		(7,293)	(3,205)	(1,387)					2,904	1,337	4,153
Unallocated general and administrative									(206,876)	(200,206)	(217,489)
Depreciation and amortization									(132,775)	(131,693)	(128,879)
System optimization gains, net									3,148	1,283	463
Reorganization and realignment costs	$ (5,834)	$ (3,375)	$ (2,911)	$ (3,910)	(12,194)				(16,030)	(16,965)	(9,068)
Impairment of long-lived assets									(8,037)	(6,999)	(4,697)
Unallocated other operating income, net									8,397	11,418	6,387
Interest expense, net									(117,737)	(115,971)	(119,618)
Loss on early extinguishment of debt					(1,346)		$ (7,150)		0	(8,496)	(11,475)
Investment (loss) income, net					$ 24,599				(225)	25,598	450,736
Other income, net									1,449	7,771	5,381
Income before income taxes									152,795	171,481	574,916
Corporate and Other
Segment Reporting, Reconciling Item for Profit from Segment to Consolidated
Unallocated general and administrative									(94,256)	(81,230)	(104,208)
Unallocated other operating income, net									190	291	444
Impact of legal reserves - Financial Institutions case settlement											27,500
Operating Segments
Segment Reporting, Reconciling Item for Profit from Segment to Consolidated
Segment profit									514,164	496,555	491,684
Operating Segments | Wendy's U.S.
Segment Reporting, Reconciling Item for Profit from Segment to Consolidated
Segment profit									393,314	369,193	355,455
Advertising funds surplus									(14,600)
Operating Segments | Wendy's International
Segment Reporting, Reconciling Item for Profit from Segment to Consolidated
Segment profit									20,119	20,246	25,597
Operating Segments | Global Real Estate & Development
Segment Reporting, Reconciling Item for Profit from Segment to Consolidated
Segment profit									$ 100,731	$ 107,116	$ 110,632