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Represents the number of units held in a unitized employer stock fund within an employee benefit plan at the reporting date.

No definition available.

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Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

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.

No definition available.

Name:	rs_EmployeeBenefitPlanInvestmentsLineItems
Namespace Prefix:	rs_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Fair and contract value of investment, excluding plan interest in master trust, held by employee stock purchase, saving, or similar plan (employee benefit plan (EBP)). Includes, but is not limited to, derivative, investment measured at net asset value per share as practical expedient, and insurance contract.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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Period Type:	instant

Fair value of investment, excluding plan interest in master trust, held by employee stock purchase, saving, or similar plan (employee benefit plan (EBP)). Includes, but is not limited to, derivative, investment measured at net asset value per share as practical expedient, and insurance contract not meeting fully-benefit responsive investment criteria.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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Name:	us-gaap-ebp_EmployeeBenefitPlanInvestmentExcludingPlanInterestInMasterTrustFairValue
Namespace Prefix:	us-gaap-ebp_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Number of shares or units of investment held by employee stock purchase, saving, or similar plan (employee benefit plan (EBP)).

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 962
-SubTopic 205
-Name Accounting Standards Codification
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Balance Type:	na
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Amount of liability of employee stock purchase, saving, or similar plan (employee benefit plan (EBP)), classified as other.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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Name:	us-gaap-ebp_EmployeeBenefitPlanOtherLiability
Namespace Prefix:	us-gaap-ebp_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Amount of receivable for employee stock purchase, saving, or similar plan (employee benefit plan (EBP)), classified as other.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 962
-SubTopic 205
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
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