Aggregate dividends declared during the period for each share of common stock outstanding.

Name:	us-gaap_CommonStockDividendsPerShareDeclared
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration

- Definition

Date the declared dividend will be paid, in CCYY-MM-DD format.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=98513485&loc=d3e4304-108586

+ Details

Name:	us-gaap_DividendPayableDateToBePaidDayMonthAndYear
Namespace Prefix:	us-gaap_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of paid and unpaid cash, stock, and paid-in-kind (PIK) dividends declared, for example, but not limited to, common and preferred stock.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 405
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6957935&loc=d3e64057-112817

+ Details

Name:	us-gaap_Dividends
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Date the dividend to be paid was declared, in CCYY-MM-DD format.

+ References

+ Details

Name:	us-gaap_DividendsPayableDateDeclaredDayMonthAndYear
Namespace Prefix:	us-gaap_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

Date the holder must own the stock to be entitled to the dividend, in CCYY-MM-DD format.

+ References

No definition available.

+ Details

Name:	us-gaap_DividendsPayableDateOfRecordDayMonthAndYear
Namespace Prefix:	us-gaap_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_DividendsPayableLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_DividendsAxis=rba_FourthQuarter2015Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DividendsAxis=rba_FirstQuarter2016Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DividendsAxis=rba_SecondQuarter2016Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DividendsAxis=rba_ThirdQuarter2016Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DividendsAxis=rba_FourthQuarter2016Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DividendsAxis=rba_FirstQuarter2017Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DividendsAxis=rba_SecondQuarter2017Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DividendsAxis=rba_ThirdQuarter2017Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DividendsAxis=rba_FourthQuarter2017Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DividendsAxis=rba_FirstQuarter2018Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DividendsAxis=rba_SecondQuarter2018Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DividendsAxis=rba_ThirdQuarter2018Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Equity and Dividends (Schedule of Quarterly Dividends Declared and Paid) (Details) - USD ($) $ / shares in Units, $ in Thousands	2 Months Ended	12 Months Ended
	Feb. 26, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Dividends Payable [Line Items]
Dividend per share	$ 0.18
Record date	Feb. 15, 2019
Payment date	Mar. 09, 2019
Fourth Quarter 2015 [Member]
Dividends Payable [Line Items]
Declaration date				Jan. 15, 2016
Dividend per share				$ 0.1600
Record date				Feb. 12, 2016
Total dividends				$ 17,154
Payment date				Mar. 04, 2016
First Quarter 2016 [Member]
Dividends Payable [Line Items]
Declaration date				May 09, 2016
Dividend per share				$ 0.1600
Record date				May 24, 2016
Total dividends				$ 17,022
Payment date				Jun. 14, 2016
Second Quarter 2016 [Member]
Dividends Payable [Line Items]
Declaration date				Aug. 05, 2016
Dividend per share				$ 0.1700
Record date				Sep. 02, 2016
Total dividends				$ 18,127
Payment date				Sep. 23, 2016
Third Quarter 2016 [Member]
Dividends Payable [Line Items]
Declaration date				Nov. 08, 2016
Dividend per share				$ 0.1700
Record date				Nov. 28, 2016
Total dividends				$ 18,156
Payment date				Dec. 19, 2016
Fourth Quarter 2016 [Member]
Dividends Payable [Line Items]
Declaration date			Jan. 23, 2017
Dividend per share			$ 0.1700
Record date			Feb. 10, 2017
Total dividends			$ 18,160
Payment date			Mar. 03, 2017
First Quarter 2017 [Member]
Dividends Payable [Line Items]
Declaration date			May 04, 2017
Dividend per share			$ 0.1700
Record date			May 23, 2017
Total dividends			$ 18,188
Payment date			Jun. 13, 2017
Second Quarter 2017 [Member]
Dividends Payable [Line Items]
Declaration date			Aug. 04, 2017
Dividend per share			$ 0.1700
Record date			Aug. 25, 2017
Total dividends			$ 18,210
Payment date			Sep. 15, 2017
Third Quarter 2017 [Member]
Dividends Payable [Line Items]
Declaration date			Nov. 08, 2017
Dividend per share			$ 0.1700
Record date			Nov. 29, 2017
Total dividends			$ 18,227
Payment date			Dec. 20, 2017
Fourth Quarter 2017 [Member]
Dividends Payable [Line Items]
Declaration date		Jan. 26, 2018
Dividend per share		$ 0.1700
Record date		Feb. 16, 2018
Total dividends		$ 18,246
Payment date		Mar. 09, 2018
First Quarter 2018 [Member]
Dividends Payable [Line Items]
Declaration date		May 09, 2018
Dividend per share		$ 0.1700
Record date		May 30, 2018
Total dividends		$ 18,342
Payment date		Jun. 20, 2018
Second Quarter 2018 [Member]
Dividends Payable [Line Items]
Declaration date		Aug. 07, 2018
Dividend per share		$ 0.1800
Record date		Aug. 29, 2018
Total dividends		$ 19,528
Payment date		Sep. 19, 2018
Third Quarter 2018 [Member]
Dividends Payable [Line Items]
Declaration date		Nov. 08, 2018
Dividend per share		$ 0.1800
Record date		Nov. 28, 2018
Total dividends		$ 19,562
Payment date		Dec. 19, 2018