Earnings Per Share (Table) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
Mar. 31, 2018	Apr. 01, 2017
Earnings Per Share [Abstract]
Earnings (loss) attributable to SunOpta Inc.	$ (4,363)	$ (11,398)
Dividends and accretion on Series A Preferred Stock	(1,967)	(1,940)
Earnings (loss) available to common shareholders	$ (6,330)	$ (13,338)
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Weighted Average Number of Shares Outstanding, Basic	86,810,000	85,929,000
Dilutive Securities, Effect on Basic Earnings Per Share, Including Options and Restrictive Stock Units	0	0
Weighted Average Number of Shares Outstanding, Diluted	86,810,000	85,929,000
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	1,984,184	1,362,347
Earnings (loss) per share - basic
Basic	$ (0.07)	$ (0.16)
Earnings (loss) per share - diluted
Diluted	$ (0.07)	$ (0.16)
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
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	657,946	84,659
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	0
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	11,333,333

Earning (loss) from operations available to common shareholders after dividend for Preferred Stock

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Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented.

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The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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The amount of net income (loss) for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period.

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Additional shares included in the calculation of diluted EPS as a result of the potentially dilutive effect of call options and warrants using the treasury stock method.

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The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

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The amount of preferred stock dividends that is an adjustment to net income apportioned to common stockholders.

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Number of [basic] shares or units, after adjustment for contingently issuable shares or units and other shares or units not deemed outstanding, determined by relating the portion of time within a reporting period that common shares or units have been outstanding to the total time in that period.

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