Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2021	May 07, 2021
Document and Entity Information
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2021
Document Transition Report	false
Entity File Number	001-13425
Entity Registrant Name	Ritchie Bros. Auctioneers Incorporated
Entity Incorporation, State or Country Code	CA
Entity Tax Identification Number	98-0626225
Entity Address, Address Line One	9500 Glenlyon Parkway
Entity Address, Address Line Two	Burnaby
Entity Address, City or Town	British Columbia
Entity Address, Country	CA
Entity Address, Postal Zip Code	V5J 0C6
City Area Code	778
Local Phone Number	331-5500
Title of 12(b) Security	Common shares
Trading Symbol	RBA
Security Exchange Name	NYSE
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		110,280,611
Entity Central Index Key	0001046102
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q1
Amendment Flag	false