XML 87 R72.htm IDEA: XBRL DOCUMENT v3.20.4

Employee Benefits - Supplemental Bonus Plan (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Contributions to Company Sponsored Retirement Plans
Company's expense for Reliance-sponsored retirement plans	$ 53.0	$ 42.1	$ 45.0
Master Plan
Contributions to Company Sponsored Retirement Plans
Company's expense for Reliance-sponsored retirement plans	21.2	22.7	28.1
Other defined contribution plans
Contributions to Company Sponsored Retirement Plans
Company's expense for Reliance-sponsored retirement plans	6.9	9.6	9.4
ESOP
Contributions to Company Sponsored Retirement Plans
Company's expense for Reliance-sponsored retirement plans			1.9
Reliance Deferred Compensation Plan
Contributions to Company Sponsored Retirement Plans
Company's expense for Reliance-sponsored retirement plans	(0.3)	5.0	0.9
SERPs
Contributions to Company Sponsored Retirement Plans
Company's expense for Reliance-sponsored retirement plans	10.5	3.3	2.9
Defined Benefit Plans
Contributions to Company Sponsored Retirement Plans
Company's expense for Reliance-sponsored retirement plans	$ 14.7	$ 1.5	$ 1.8

X

- References

No definition available.

+ Details

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

X

- Definition

Amount of cost (reversal of cost) for pension and other postretirement benefits.

+ References

No definition available.

+ Details

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

X

- Details

Name:	us-gaap_RetirementPlanTypeAxis=rs_MasterPlanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_RetirementPlanTypeAxis=us-gaap_OtherPensionPlansDefinedBenefitMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_RetirementPlanTypeAxis=rs_EmployeeStockOwnershipPlanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_RetirementPlanTypeAxis=rs_DeferredCompensationPlanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_RetirementPlanTypeAxis=us-gaap_SupplementalEmployeeRetirementPlanDefinedBenefitMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_RetirementPlanTypeAxis=us-gaap_PensionPlansDefinedBenefitMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: