Earnings per share (Table) (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 29, 2018	Dec. 30, 2017	Dec. 31, 2016
Earnings Per Share Abstract
Income (Loss) from Continuing Operations Attributable to Parent	$ (109,205)	$ (135,320)	$ (50,618)
Dividends and accretion on Series A Preferred Stock	(7,909)	(7,809)	1,812
Earning (loss) from continuing operations available to common shareholders	(117,114)	(143,129)	(52,430)
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to SunOpta Inc	0	0	(570)
Earnings (loss) available to common shareholders	$ (117,114)	$ (143,129)	$ (53,000)
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Weighted Average Number of Shares Outstanding, Basic	87,082,000	86,355,000	85,569,000
Dilutive Securities, Effect on Basic Earnings Per Share, Including Options and Restrictive Stock Units	0	0	0
Weighted Average Number of Shares Outstanding, Diluted	87,082,000	86,355,000	85,569,000
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	2,384,249	2,540,189	2,321,448
Earnings (loss) per share - basic
from continuing operations basic	$ (1.34)	$ (1.66)	$ (0.61)
from discontinued operations basic	0	0	(0.01)
Earnings Per Share Total	(1.34)	(1.66)	(0.62)
Earnings (loss) per share - diluted
from continuing operations diluted	(1.34)	(1.66)	(0.61)
from discontinued operations diluted	0	0	(0.01)
Earnings Per Share Diluted Total	$ (1.34)	$ (1.66)	$ (0.62)
Options Held [Member]
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Dilutive Securities, Effect on Basic Earnings Per Share, Including Options and Restrictive Stock Units	0	0	0
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	452,316	815,952	66,166
Warrant [Member]
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Dilutive Securities, Effect on Basic Earnings Per Share, Including Options and Restrictive Stock Units	0	0	0
Series A Preferred Stock [Member]
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Dilutive Securities, Effect on Basic Earnings Per Share, Including Options and Restrictive Stock Units	0
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	11,333,333	11,333,333	2,670,320