Document and Entity Information - USD ($) $ in Millions	12 Months Ended
	Dec. 28, 2019	Feb. 21, 2020	Jun. 28, 2019
Entity Registrant Name	SUNOPTA INC.
Entity Shell Company	false
Entity Current Reporting Status	Yes
Entity Emerging Growth Company	false
Entity Small Business	false
Document Fiscal Period Focus	FY
Document Fiscal Year Focus	2019
Amendment Flag	false
Document Period End Date	Dec. 28, 2019
Document Type	10-K
Entity Common Stock, Shares Outstanding		88,148,363
Entity Public Float			$ 230
Entity Voluntary Filers	Yes
Entity Well-known Seasoned Issuer	No
Entity Filer Category	Accelerated Filer
Current Fiscal Year End Date	--12-28
Entity Central Index Key	0000351834
Entity File Number	001-34198
Entity Address, Address Line One	2233 Argentia Road
Entity Address, City or Town	Mississauga
City Area Code	905
Local Phone Number	821-9669
Entity Address, State or Province	ON
Entity Interactive Data Current	Yes
Entity Tax Identification Number	00-0000000
Entity Address, Address Line Two	Suite 401
Entity Incorporation, State or Country Code	Z4
Entity Address, Postal Zip Code	L5N 2X7
Document Transition Report	false
Entity Address, Country	CA
Document Annual Report	true
The Nasdaq Stock Market | Common Shares
Trading Symbol	STKL
Security Exchange Name	NASDAQ
Title of 12(b) Security	Common Shares
The Toronto Stock Exchange | Common Shares
Trading Symbol	SOY
Title of 12(b) Security	Common Shares