Preferred Shares (Narrative) (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 30, 2017	Dec. 31, 2016	Jan. 02, 2016
Temporary Equity [Line Items]
Dividends	$ (1,700)	$ (1,590)	$ 0
Series A Preferred Stock [Member] | Oaktree Organics, L.P. and Oaktree Huntington Investment Fund II, L.P.
Temporary Equity [Line Items]
Preferred Stock Shares Issued	85,000
Preferred Stock Value	$ 85,000
Preferred Stock Issuance Costs	$ 6,000
Preferred Stock Redemption Terms	At any time on or after the fifth anniversary of the Closing Date, SunOpta Foods may redeem all of the Preferred Stock for an amount, per share of Preferred Stock, equal to the value of the liquidation preference at such time. The carrying value of the Preferred Stock is being accreted to the redemption amount of $85.0 million through charges to retained earnings over the period preceding the fifth anniversary of the Closing Date, which accretion amounted to $1.0 million and $0.2 million for the year ended December 30, 2017 and period ended December 31, 2016.
Preferred Stock Accretion To Redemption Value2	$ 1,000	$ 200
Preferred Stock Dividend Preference Or Restrictions	In connection with the Subscription Agreement, the Company agreed to, among other things (i) ensure SunOpta Foods has sufficient funds to pay its obligations under the terms of the Preferred Stock and (ii) grant each holder of Preferred Stock (the “Holder”) the right to exchange the Preferred Stock for shares of common stock of the Company (the “Common Shares”). The Preferred Stock is non-participating with the Common Shares in dividends and undistributed earnings of the Company.
Preferred Stock Liquidation Preference	$ 1,000
Preferred Stock Dividend Payment Terms	Cumulative preferred dividends accrue daily on the Preferred Stock at an annualized rate of 8.0% prior to October 5, 2025 and 12.5% thereafter, in each case of the liquidation preference (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 October 5, 2025, 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. After October 4, 2025, the failure to pay dividends in cash will be an event of non-compliance. The Preferred Stock ranks senior to the shares of common stock of SunOpta Foods with respect to dividend rights and rights on the distribution of assets on any liquidation, winding up or dissolution of the Company or SunOpta Foods.
Dividends	$ 1,700
Convertible Preferred Stock Terms Of Conversion	At any time, the Holders may exchange their shares of Preferred Stock, in whole or in part, into the number of Common Shares equal to, per share of Preferred Stock, the quotient of the liquidation preference divided by $7.50 (such price, the “Exchange Price” and such quotient, the “Exchange Rate”). As at December 30, 2017, the aggregate shares of Preferred Stock outstanding were exchangeable into 11,333,333 Common Shares. 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 $7.00 (subject to adjustment in certain circumstances).
Convertible Preferred Stock Settlement Terms	SunOpta Foods may cause the Holders to exchange all of the Preferred Stock into a number of Common Shares based on the applicable Exchange Price if (i) fewer than 10% of the shares of Preferred Stock issued on the Closing Date remain outstanding or (ii) on or after the third anniversary of the Closing Date, the average volume-weighted average price of the Common Shares during the then preceding 20 trading day period is greater than 200% of the Exchange Price.
Preferred Stock Voting Rights	In connection with the Subscription Agreement, the Company issued 11,333,333 Special Shares, Series 1 (the “Special Voting Shares”) to the Investors, which entitle the Investors to one vote per Special Voting Share on all matters submitted to a vote of the holders of Common Shares, together as a single class, subject to certain exceptions. Additional Special Voting Shares will be issued, or existing Special Voting Shares will be redeemed, as necessary to ensure that the aggregate number of Special Voting Shares outstanding is equal to the number of shares of Preferred Stock outstanding from time to time multiplied by the Exchange Rate in effect at such time. As at December 30, 2017, 11,333,333 Special Voting Shares were issued and outstanding, which represented an approximate 11.7% voting interest in the Company. The Special Voting Shares are not transferable and the voting rights associated with the Special Voting Shares will terminate upon the transfer of the Preferred Stock to a third party, other than a controlled affiliate of the Investors. The Investors are entitled to designate up to two nominees for election to the Board of Directors of the Company (the “Board”) and have the right to designate one individual to attend meetings of the Board as a non-voting observer, subject to the Investors maintaining certain levels of beneficial ownership of Common Shares on an as-exchanged basis.
Preferred Stock Participation Rights	For so long as the Investors beneficially own or control at least 50% of the Preferred Stock issued on the Closing Date, including any corresponding Common Shares into which such Preferred Stock are exchanged, the Investors will be entitled to (i) participation rights with respect to future equity offerings of the Company; and (ii) governance rights, including the right to approve certain actions proposed to be taken by the Company and its subsidiaries.