Summary of Significant Accounting Policies - Reclassification (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Reclassification
Other long-term liabilities	$ 51.4	$ 50.2
Deferred Compensation Plan Liabilities Reclassification \| Reclassification Adjustment
Reclassification
Long-term retirement benefits		(43.2)
Other long-term liabilities		$ 43.2

Aggregate carrying value as of the balance sheet date of the liabilities for all deferred compensation arrangements payable and amount of liability, recognized in statement of financial position, for pension, other postretirement and postemployment benefits, classified as noncurrent.

No definition available.

Name:	rs_DeferredCompensationLiabilityAndPensionAndOtherPostretirementAndPostemploymentBenefitPlansLiabilitiesNoncurrent
Namespace Prefix:	rs_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant