DESCRIPTION OF THE PLAN - Transfers from Other Plans (Details) - Reliance, Inc. Master 401(k) Plan	12 Months Ended
Dec. 31, 2025 USD ($)
DESCRIPTION OF THE PLAN
Transfers from other plans	$ 36,741,619
American Alloy Steel 401(k) Plan
DESCRIPTION OF THE PLAN
Transfers from other plans	23,505,710
Cooksey Iron & Metal Co., Inc. 401(k) Profit Sharing Plan
DESCRIPTION OF THE PLAN
Transfers from other plans	8,188,709
Southern Steel Supply 401(k) Plan
DESCRIPTION OF THE PLAN
Transfers from other plans	$ 5,047,200

Amount of net asset available for benefit transferred to (from) employee stock purchase, saving, or similar plan (employee benefit plan (EBP)) from (to) external plan.

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

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 962
-SubTopic 205
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.6A-05(a)(Schedule III))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477804/962-205-S99-1

Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 962
-SubTopic 205
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478416/962-205-50-1

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 962
-SubTopic 205
-Name Accounting Standards Codification
-Section 45
-Paragraph 8
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477063/962-205-45-8

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Namespace Prefix:	us-gaap-ebp_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration