Name:	rs_EmployeeBenefitPlanDiscretionaryProfitSharingContributionEligibilityServicePeriod
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Balance Type:	na
Period Type:	duration

Minimum number of hours of employee service required for a participant to become eligible for discretionary profit sharing contributions under the employee benefit plan.

No definition available.

Name:	rs_EmployeeBenefitPlanDiscretionaryProfitSharingContributionMinimumHoursOfServiceRequirement
Namespace Prefix:	rs_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

Percentage of automatic increase per year in pretax annual compensation that participant in employee stock purchase, saving, or similar plan (employee benefit plan (EBP)), contributes to total pretax annual compensation.

No definition available.

Name:	rs_EmployeeBenefitPlanParticipantContributionAutomaticIncreasePerYearPercent
Namespace Prefix:	rs_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

Percentage of maximum automatic salary deferral contribution rate under automatic enrollment.

No definition available.

Name:	rs_EmployeeBenefitPlanParticipantContributionMaximumAutomaticEnrollmentContributionPercent
Namespace Prefix:	rs_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

Represents the percentage of vesting.

No definition available.

Name:	rs_EmployeeBenefitPlanVestingPercentage
Namespace Prefix:	rs_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

Indicates (true false) whether description of employee stock purchase, saving, or similar plan (employee benefit plan (EBP)) is published and made available.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 962
-SubTopic 205
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478416/962-205-50-1

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Namespace Prefix:	us-gaap-ebp_
Data Type:	xbrli:booleanItemType
Balance Type:	na
Period Type:	duration

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.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 962
-SubTopic 205
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478416/962-205-50-1

Name:	us-gaap-ebp_EmployeeBenefitPlanDescriptionOfPlanLineItems
Namespace Prefix:	us-gaap-ebp_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Percentage of eligible compensation contributed for participant automatically enrolled in employee stock purchase, saving, or similar plan (employee benefit plan (EBP)).

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 962
-SubTopic 325
-Name Accounting Standards Codification
-Section 55
-Paragraph 17
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478873/962-325-55-17

Name:	us-gaap-ebp_EmployeeBenefitPlanParticipantContributionAutomaticDeferralRate
Namespace Prefix:	us-gaap-ebp_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

Percentage of maximum pretax annual compensation that participant in employee stock purchase, saving, or similar plan (employee benefit plan (EBP)), is permitted to contribute to total pretax annual compensation.

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Namespace Prefix:	us-gaap-ebp_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

Name:	dei_LegalEntityAxis=rs_EBP001Member
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Balance Type:
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Name:	rs_EmployeeBenefitPlanYearsOfVestingServiceAxis=rs_EmployeeBenefitPlanYearsOfVestingServiceTrancheOneMember
Namespace Prefix:
Data Type:	na
Balance Type:
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Name:	rs_EmployeeBenefitPlanYearsOfVestingServiceAxis=rs_EmployeeBenefitPlanYearsOfVestingServiceTrancheTwoMember
Namespace Prefix:
Data Type:	na
Balance Type:
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Name:	rs_EmployeeBenefitPlanYearsOfVestingServiceAxis=rs_EmployeeBenefitPlanYearsOfVestingServiceTrancheThreeMember
Namespace Prefix:
Data Type:	na
Balance Type:
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Name:	rs_EmployeeBenefitPlanYearsOfVestingServiceAxis=rs_EmployeeBenefitPlanYearsOfVestingServiceTrancheFourMember
Namespace Prefix:
Data Type:	na
Balance Type:
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Name:	rs_EmployeeBenefitPlanYearsOfVestingServiceAxis=rs_EmployeeBenefitPlanYearsOfVestingServiceTrancheFiveMember
Namespace Prefix:
Data Type:	na
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