Subsequent Event (Narrative) (Details) - Subsequent Event [Member] $ / shares in Units, $ in Thousands	1 Months Ended
	Apr. 24, 2020 USD ($) $ / shares shares
Series B-1 Preferred Stock [Member] | Stock issued to each recipient [Member]
Subsequent Event [Line Items]
Preferred Stock, Shares Issued	15,000
Series B-1 Preferred Stock [Member] | Oaktree and Engaged [Member]
Subsequent Event [Line Items]
Preferred Stock, Value, Issued | $	$ 30,000
Preferred Stock, Shares Issued	30,000
Preferred Stock, Liquidation Preference Per Share | $ / shares	$ 1,000
Preferred Stock Annualized Rate	8.00%
Preferred Stock, Dividend Payment Terms	Cumulative preferred dividends accrue daily on the Series B-1 Preferred Stock at an annualized rate of 8.0% of the liquidation preference prior to September 30, 2029 and 10.0% of the liquidation preference thereafter (subject to an increase of 1.0% per quarter, up to a maximum rate of 5.0% per quarter on the occurrence of certain events of non-compliance). Prior to September 30, 2029, SunOpta Foods may pay dividends in cash or elect, in lieu of paying cash, to add the amount that would have been paid to the liquidation preference. The failure to pay dividends in cash for any quarter ending after September 30, 2029 will be an event of non-compliance.
Convertible Preferred Stock, Terms of Conversion	At any time, the Series B-1 Preferred Stock may be exchanged, in whole or in part, into the number of Common Shares equal to, per share of Series B-1 Preferred Stock, the quotient of the liquidation preference divided by $2.50 (such price, the "Series B-1 Exchange Price" and such quotient, the "Series B-1 Exchange Rate").
Number of common shares available due to exchangeable preferred stock	12,000,000
Preferred stock exchange, description of exchange price	The Exchange Price is subject to certain anti-dilution adjustments, including a weighted-average adjustment for issuances of Common Shares below the Exchange Price, provided that the Exchange Price may not be lower than $2.00 (subject to adjustment in certain circumstances).
Convertible preferred stock, Settlement terms	SunOpta Foods may cause the holders of the Series B-1 Preferred Stock to exchange all of their shares of Series B-1 Preferred Stock into a number of Common Shares equal to the number of shares of Series B-1 Preferred Stock outstanding multiplied by the Series B-1 Exchange Rate if (i) fewer than 10% of the shares of Series B-1 Preferred Stock issued on April 24, 2020 remain outstanding, or (ii) on or after April 24, 2023, the average volume-weighted average price of the Common Shares during the then preceding 20 trading day period is greater than 200% of the Series B-1 Exchange Price then in effect. At any time, if a holder of Series B Preferred Stock elects to exchange, or SunOpta Foods causes an exchange of Series B Preferred Stock, the number of Common Shares delivered to each applicable holder may not cause such holder’s beneficial ownership to exceed 19.99% of the Common Shares that would be outstanding immediately following such exchange (the “Series B Exchange Cap”).
Series B-2 Preferred Stock [Member] | Stock issued to each recipient [Member]
Subsequent Event [Line Items]
Right but not obligation to purchase Preferred Stock shares	15,000
Series B-2 Preferred Stock [Member] | Oaktree and Engaged [Member]
Subsequent Event [Line Items]
Right but not obligation to purchase Preferred Stock shares	30,000
Right but not obligation to purchase preferred stock shares for aggregate consideration | $	$ 30,000
Convertible Preferred Stock, Terms of Conversion	The exchange price for the Series B-2 Preferred Stock (such price, the "Series B-2 Exchange Price") will initially be that amount which is equal to a 30% premium to the 15-day volume-weighted average price of the Common Shares determined as at the date of notice, provided that the Series B-2 Exchange Price cannot be less than $2.00 or greater than $3.50 per underlying Common Share. The dividend terms on the Series B-2 Preferred Stock would be the same as the Series B-1 Preferred Stock. Oaktree and Engaged will be entitled to vote the Series B Preferred Stock with the Common Shares on an as-exchanged basis, subject to a permanent 19.99% voting cap. As a result of the voting cap, each of Oaktree and Engaged will only be able to vote its Series B Preferred Stock to the extent that, when taken together with any other voting securities each investor controls, such votes do not exceed 19.99% of the votes eligible to be cast by all security holders of the Company. On April 24, 2020, the Company designated Special Shares, Series 2 to serve as the mechanism for attaching exchanged voting to the Series B Preferred Stock. The Special Shares, Series 2 entitle the holder thereof to one vote per Special Share, Series 2 on all matters submitted to a vote of the holders of Common Shares, voting together as a single class, subject to certain exceptions. The Special Shares, Series 2 are not transferrable and the voting rights associated with the Special Shares, Series 2 will terminate upon the transfer of the shares of Series B Preferred Stock to a third party, other than an affiliate of Oaktree or Engaged, as applicable. On April 24, 2020, 6,000,000 Special Shares, Series 2 were issued to Engaged, equal to the number of Common Shares issuable to Engaged on the exchange of all of the shares of Series B-1 Preferred Stock held by it, and no Special Shares, Series 2 were issued to Oaktree, as Oaktree was subject to the Series B Exchange Cap.