Value Creation Plan (Exiting Flexible Resealable Pouch and Nutrition Bar Product Lines and Operations) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 30, 2017	Dec. 31, 2016	Jan. 02, 2016
Restructuring Cost And Reserve [Line Items]
Proceeds From Sale Of Property Plant And Equipment	$ 2,385	$ 254	$ 1,138
Revenues	1,279,593	1,346,731	1,145,134
Earnings (loss) from continuing operations before income taxes	$ (170,397)	(74,361)	(6,522)
Flexible Resealable Pouch [Member]
Restructuring Cost And Reserve [Line Items]
Property Plant And Equipment Impairment Or Disposal Disclosure	On July 26, 2017, SunOpta Foods entered an agreement with Skjodt-Barrett Contract Packaging LLC to sell equipment used in the production of flexible resealable pouches at the Company’s Allentown, Pennsylvania facility for gross proceeds of $2.0 million ($1.3 million net of costs to sell). The transaction closed on November 3, 2017. The Company continued to produce flexible resealable pouch products for existing customers until the closing date. The Company’s aseptic beverage operations were not affected by the sale of assets, and the Company will continue to produce aseptic beverages at its Allentown facility.
Proceeds From Sale Of Property Plant And Equipment	$ 2,000
Nutrition Bar [Member]
Restructuring Cost And Reserve [Line Items]
Property Plant And Equipment Impairment Or Disposal Disclosure	On September 27, 2017, the Company announced its intention to exit its nutrition bar product lines and operations in Carson City, Nevada, with final production for customers ending on December 20, 2017. On November 21, 2017, the Company entered into an agreement to sell the nutrition bar equipment for gross proceeds of $0.9 million, of which $0.2 million was received on signing and $0.7 million was received at closing on January 3, 2018. The Company is pursuing potential parties interested assuming the facility lease.
Proceeds From Sale Of Property Plant And Equipment	$ 900
Flexible Resealable Pouch and Nutrition Bar [Member]
Restructuring Cost And Reserve [Line Items]
Revenues	53,100	59,300	58,100
Earnings (loss) from continuing operations before income taxes	$ (24,400)	$ (2,100)	$ (2,800)
Restructuring and Related Cost, Description	For the year ended December 30, 2017, the loss before income taxes from these operations included write-offs of accounts receivable and inventory ($2.9 million) and impairments of long-lived assets ($13.2 million) related to the exit activities, as well as employee termination costs of $1.7 million. These operations were included in the Consumer Products operating segment.