Contingencies (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017
Contingencies [Abstract]
Assets guaranteed under contract	$ 41,461	$ 30,948
Percentage of assets expected to be sold	51.00%	27.00%

Minimum level of proceeds guaranteed to consignors on the sale at auction of that consignor's equipment.

No definition available.

Name:	rba_GuarantorObligationsProceedsOnAuctionSale
Namespace Prefix:	rba_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration