Name:	rs_DebtInstrumentCovenantPercentageOfEBITDAParentAndSubsidiaryGuarantorsMinimum
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Represents the percentage of consolidated tangible assets which the subsidiary guarantors together with the entity required to own under the terms of the financial covenants.

No definition available.

Name:	rs_DebtInstrumentCovenantPercentageOfTangibleAssetsParentAndSubsidiaryGuarantorsMinimum
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Represents the number of tranches comprising the debt issuance.

No definition available.

Name:	rs_DebtInstrumentIssuedTranchesNumber
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Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

Represents the lump sum amount payable at the maturity of the debt instrument.

No definition available.

Name:	rs_DebtInstrumentPaymentAtMaturity
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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Represents the percentage of annual amortization of term loan after specified period.

No definition available.

Name:	rs_DebtInstrumentTermLoanAnnualAmortizationPercentageAfterSpecifiedPeriod
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Data Type:	num:percentItemType
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Represents the redemption price as a percentage of the principal amount at which the debt instrument may be required to be redeemed by the entity in the event of a change of control or downgrade of the entity's credit rating.

No definition available.

Name:	rs_DebtRedemptionPriceDueToChangeOfControlAndDowngradeOfCreditRatingAsPercentageOfPrincipalAmount
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Data Type:	num:percentItemType
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Period Type:	duration

Represents the number of banks as lenders of the line of credit facility.

No definition available.

Name:	rs_LineOfCreditFacilityBankLendersNumber
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Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

Increased maximum borrowing capacity under the credit subject to approval of the lenders and certain other conditions.

No definition available.

Name:	rs_LineOfCreditFacilityContingentIncreaseToMaximumBorrowingCapacity
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Data Type:	xbrli:monetaryItemType
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Represents the parent entity's interest in net assets of the subsidiary, expressed as a percentage.

No definition available.

Name:	rs_MajorityInterestOwnershipPercentageByParent
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Data Type:	num:percentItemType
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Percentage points added to the reference rate to compute the variable rate on the debt instrument.

No definition available.

Name:	us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
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Data Type:	num:percentItemType
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Period Type:	duration

Amount of long-term debt before deduction of unamortized discount or premium. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt, with initial maturities beyond one year or the normal operating cycle, if longer.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.22)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 20

-Article 5

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 16

-Article 9

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Data Type:	xbrli:monetaryItemType
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Period Type:	instant

The reference rate for the variable rate of the debt instrument, such as LIBOR or the US Treasury rate and the maturity of the reference rate used, such as three months or six months LIBOR.

No definition available.

Name:	us-gaap_DebtInstrumentDescriptionOfVariableRateBasis
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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Contractual interest rate for funds borrowed, under the debt agreement.

Name:	us-gaap_DebtInstrumentInterestRateStatedPercentage
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Data Type:	num:percentItemType
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:	us-gaap_DebtInstrumentLineItems
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Data Type:	xbrli:stringItemType
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Period Type:	duration

Weighted average interest rate of debt outstanding.

No definition available.

Name:	us-gaap_DebtWeightedAverageInterestRate
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-03.16)

-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.7-03.16)

-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 19, 20, 22

-Article 5

Name:	us-gaap_LineOfCredit
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

Name:	us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding).

Name:	us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

The fee, expressed as a percentage of the line of credit facility, for available but unused credit capacity under the credit facility.

No definition available.

Name:	us-gaap_LineOfCreditFacilityUnusedCapacityCommitmentFeePercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

The cash inflow during the period from additional borrowings in aggregate debt. Includes proceeds from short-term and long-term debt.

No definition available.

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

Name:	us-gaap_BusinessAcquisitionAxis=rs_RealEstatePropertiesPortfolioMember
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Name:	us-gaap_FinancialInstrumentAxis=rs_ThirdAmendedAndRestatedCreditAgreementAndSeniorUnsecuredNotesDueApril2023IndentureMember
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Name:	us-gaap_DebtInstrumentAxis=rs_UnsecuredRevolvingCreditFacilityMember
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Data Type:	na
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Name:	us-gaap_VariableRateAxis=us-gaap_LondonInterbankOfferedRateLIBORMember
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Data Type:	na
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Name:	us-gaap_VariableRateAxis=us-gaap_PrimeRateMember
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Data Type:	na
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Name:	us-gaap_DebtInstrumentAxis=rs_SeniorUnsecuredNotesPubliclyTradedMember
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Data Type:	na
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Name:	us-gaap_DebtInstrumentAxis=rs_SeniorUnsecuredNotesIssuedNovember2006Member
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Data Type:	na
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Name:	us-gaap_DebtInstrumentAxis=rs_SeniorUnsecuredNotesDueNovember2016Member
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Data Type:	na
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Name:	us-gaap_DebtInstrumentAxis=rs_SeniorUnsecuredNotesDueNovember2036Member
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Data Type:	na
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Name:	us-gaap_DebtInstrumentAxis=rs_SeniorUnsecuredNotesDue2023Member
Namespace Prefix:
Data Type:	na
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Name:	us-gaap_DebtInstrumentAxis=rs_UnsecuredRevolvingCreditFacilityAndSeniorUnsecuredNotesMember
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Name:	us-gaap_DebtInstrumentAxis=rs_TermLoanDueApril2018Member
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Name:	us-gaap_DebtInstrumentAxis=rs_OtherRevolvingCreditFacilityMember
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Data Type:	na
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Name:	us-gaap_DebtInstrumentAxis=rs_IndustrialRevenueBondsMember
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