Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 28, 2019	Dec. 29, 2018	Dec. 30, 2017
Income Statement [Abstract]
Revenues	$ 1,190,022	$ 1,260,852	$ 1,279,593
Cost of goods sold	1,074,769	1,137,382	1,134,506
Gross profit	115,253	123,470	145,087
Selling, general and administrative expenses	108,340	108,248	127,507
Intangible asset amortization	10,971	11,038	11,195
Other expense (income), net	(40,048)	2,825	23,660
Goodwill impairment		81,222	115,000
Foreign exchange loss (gain)	(1,304)	252	5,618
Earnings (loss) before the following	37,294	(80,115)	(137,893)
Interest expense, net	34,677	34,406	32,504
Earnings (loss) before income taxes	2,617	(114,521)	(170,397)
Provision for (recovery of) income taxes	3,221	(5,378)	(35,829)
Net loss	(604)	(109,143)	(134,568)
Earnings attributable to non-controlling interests	154	62	752
Loss attributable to SunOpta Inc.	(758)	(109,205)	(135,320)
Dividends and accretion on Series A Preferred Stock	(8,022)	(7,909)	(7,809)
Loss attributable to common shareholders	$ (8,780)	$ (117,114)	$ (143,129)
Loss per share
Basic (in dollars per share)	$ (0.10)	$ (1.34)	$ (1.66)
Diluted (in dollars per share)	$ (0.10)	$ (1.34)	$ (1.66)
Weighted-average common shares outstanding (000s)
Basic	87,787	87,082	86,355
Diluted	87,787	87,082	86,355