Subsequent events (Second LienNotes Narrative) (Details) - USD ($) $ in Millions	1 Months Ended	9 Months Ended
	Oct. 20, 2016	Oct. 01, 2016
Term Loan Facility [Member]
Subsequent Event [Line Items]
Debt Conversion Original Debt Type Of Debt		The remaining $231.0 million aggregate principal amount of Initial Loans matured on October 9, 2016 and automatically converted into a like principal amount of term loans (such converted loans, the “Term Loans”), with a maturity date of October 9, 2022. The Term Loans bore interest at a rate of 9.5% per annum. On October 20, 2016, all of the outstanding Term Loans were exchanged for a corresponding amount of 9.5% Senior Secured Second Lien Notes due 2022 (the “Notes”) issued by SunOpta Foods
Subsequent Event [Member] | Secured Debt [Member]
Subsequent Event [Line Items]
Debt Instrument, Issuance Date	Oct. 20, 2016
Debt Instrument, Face Amount	$ 231
Debt Instrument Interest Rate Stated Percentage	9.50%
Debt Instrument, Frequency of Periodic Payment	semi-annually in arrears
Debt Conversion Original Debt Type Of Debt	SunOpta Foods issued $231.0 million aggregate principal amount of Notes in exchange for the corresponding principal amount of Term Loans borrowed under the Second Lien Loan Agreement. The Term Loans were the result of the automatic conversion on October 9, 2016 of the outstanding Initial Loans borrowed under the Second Lien Loan Agreement
Debt Instrument, Maturity Date	Oct. 09, 2022
Debt Instrument Redemption Description	At any time prior to October 9, 2018, SunOpta Foods may redeem some or all of the Notes at any time and from time to time at a “make-whole” redemption price set forth in the indenture governing the Notes. On or after October 9, 2018, SunOpta Foods may redeem the Notes, in whole or in part, at any time at the redemption prices equal to 107.125% through October 8, 2019, 104.750% from October 9, 2019 through October 8, 2020, 102.375% from October 9, 2020 through October 8, 2021 and at par thereafter, plus accrued and unpaid interest, if any, to but excluding the date of redemption. In addition, prior to October 9, 2018, SunOpta Foods may, on one or more occasions, redeem up to 35% of the aggregate principal amount of the Notes with the proceeds of certain equity offerings at a redemption price equal to 109.500% of the principal amount of the Notes redeemed, plus accrued and unpaid interest, if any, to but excluding the date of redemption. At any time prior to October 9, 2018, SunOpta Foods may also redeem, during each twelve-month period beginning on October 20, 2016, up to 10% of the aggregate principal amount of the Notes at a price equal to 103% of the aggregate principal amount of the Notes being redeemed, plus accrued and unpaid interest, if any, to but excluding the date of redemption. In the event of a change of control, SunOpta Foods will be required to make an offer to repurchase the Notes at 101% of their principal amount, plus accrued and unpaid interest, if any, to the date of purchase.