Commitments and Contingencies (Narrative) (Details) $ in Millions	6 Months Ended
	Jun. 30, 2018 USD ($)
Employment Matter [Member]
Loss Contingencies [Line Items]
Loss Contingency Accrual Carrying Value Current	$ 5.0
Loss Contingency Allegations	On April 19, 2013, a class-action complaint, in the case titled De Jesus, et al. v. Frozsun, Inc. d/b/a Frozsun Foods, was filed against Sunrise Growers, Inc. (“Sunrise”) (then named Frozsun, Inc.) in California Superior Court, Santa Barbara County seeking damages, equitable relief and reasonable attorneys’ fees for alleged wage and hour violations. This case includes claims for failure to pay all hours worked, failure to pay overtime wages, meal and rest period violations, waiting-time penalties, improper wage statements and unfair business practices. The putative class includes 10,611 non-exempt hourly employees from Sunrise’s production facilities in Santa Maria and Oxnard, California. The parties attended mediation on October 12, 2017, and reached a general agreement to resolve the matter on a class-wide basis for $5.0 million.
Product Recall [Member]
Loss Contingencies [Line Items]
Loss Contingency Damages Sought	On November 20, 2017, Treehouse Foods, Inc., several of its related entities, and its insurer filed a lawsuit against the Company in the Circuit Court of Cook County, Illinois titled Treehouse Foods, Inc. et al. v. SunOpta Grains and Food, Inc. The Company was served with the Summons and Complaint on January 24, 2018, and the plaintiffs filed an Amended Complaint on April 23, 2018. The plaintiffs allege economic damages resulting from the Company’s 2016 voluntary recall of certain roasted sunflower kernel products due to the potential for Listeria monocytogenes contamination. The case includes claims for breach of express and implied warranty, negligence, strict liability, and indemnity seeking $16.2 million in damages. There are no allegations of personal injury. The Company is vigorously defending itself against these claims. The Company cannot reasonably predict the outcome of this claim, nor can it estimate the amount of loss, or range of loss, if any, that may result from this claim.
Loss Contingency Damages Sought Value	$ 16.2