Transfer Of Accounts Receivable Program, Termination

No definition available.

Name:	cmc_TransferOfAccountsReceivableProgramTermination
Namespace Prefix:	cmc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Transfer of Accounts Receivable Program, Face Amount

+ References

No definition available.

+ Details

Name:	cmc_TransferofAccountsReceivableProgramFaceAmount
Namespace Prefix:	cmc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Transfers of Accounts Receivable Outstanding

+ References

No definition available.

+ Details

Name:	cmc_TransfersofAccountsReceivableOutstanding
Namespace Prefix:	cmc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of short-term and long-term debt and lease obligation.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.13,16)
-URI https://asc.fasb.org/extlink&oid=126897435&loc=d3e534808-122878

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03.16)
-URI https://asc.fasb.org/extlink&oid=126734703&loc=d3e572229-122910

+ Details

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

- Definition

Face (par) amount of debt instrument at time of issuance.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 1B
-Subparagraph (a)
-URI https://asc.fasb.org/extlink&oid=123466505&loc=SL123495323-112611

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI https://asc.fasb.org/extlink&oid=124435984&loc=d3e28551-108399

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI https://asc.fasb.org/extlink&oid=114775985&loc=d3e28878-108400

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 50
-Paragraph 1
-URI https://asc.fasb.org/extlink&oid=124429444&loc=SL124452920-239629

Reference 5: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 55
-Paragraph 69C
-URI https://asc.fasb.org/extlink&oid=123466577&loc=SL123495737-112612

Reference 6: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 55
-Paragraph 69B
-URI https://asc.fasb.org/extlink&oid=123466577&loc=SL123495735-112612

+ Details

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

- Definition

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.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of the cost of borrowed funds accounted for as interest expense for debt.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 6
-Subparagraph (b)
-URI https://asc.fasb.org/extlink&oid=123466204&loc=SL6036836-161870

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.8)
-URI https://asc.fasb.org/extlink&oid=126953954&loc=SL114868664-224227

Reference 3: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 55
-Paragraph 69F
-URI https://asc.fasb.org/extlink&oid=123466577&loc=SL123495745-112612

Reference 4: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 55
-Paragraph 69E
-URI https://asc.fasb.org/extlink&oid=123466577&loc=SL123495743-112612

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 1F
-Subparagraph (b)
-URI https://asc.fasb.org/extlink&oid=123466505&loc=SL123495355-112611

+ Details

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

- Definition

The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.

+ References

No definition available.

+ Details

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

- Definition

Amount of current borrowing capacity under the credit facility considering any current restrictions on the amount that could be borrowed (for example, borrowings may be limited by the amount of current assets), but without considering any amounts currently outstanding under the facility.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.19(b),22(b))
-URI https://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

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

- Definition

Fair value of the amount outstanding under the credit facility.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 10
-URI https://asc.fasb.org/extlink&oid=123594938&loc=d3e13433-108611

+ Details

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

- Definition

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.

+ References

+ Details

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

- Definition

Weighted average interest rate of long-term debt outstanding calculated at point in time.

+ References

No definition available.

+ Details

Name:	us-gaap_LongtermDebtWeightedAverageInterestRate
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The cash outflow for debt initially having maturity due after one year or beyond the normal operating cycle, if longer.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 15
-Subparagraph (b)
-URI https://asc.fasb.org/extlink&oid=126954810&loc=d3e3291-108585

+ Details

Name:	us-gaap_RepaymentsOfLongTermDebt
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Details

Name:	dei_LegalEntityAxis=cmc_CmcpMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=cmc_PolandProgramMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=cmc_A330MillionNotesAt4875DueMay2023Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=cmc_PolandTermLoanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CreditFacilityAxis=us-gaap_RevolvingCreditFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_LineOfCreditMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=cmc_CreditAgreementMaturing2027Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=cmc_CreditAgreementMaturingMarch2026Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CreditFacilityAxis=us-gaap_SecuredDebtMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_StandbyLettersOfCreditMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

CREDIT ARRANGEMENTS (Narrative) (Details)			3 Months Ended		9 Months Ended
CREDIT ARRANGEMENTS (Narrative) (Details)	May 15, 2023 USD ($)	Nov. 10, 2022 USD ($)	May 31, 2023 USD ($)	May 31, 2022 USD ($)	May 31, 2023 USD ($)	May 31, 2022 USD ($)	May 31, 2023 PLN (zł)	Nov. 09, 2022 USD ($)	Oct. 31, 2022 USD ($)	Aug. 31, 2022 USD ($)	Aug. 31, 2022 PLN (zł)	May 31, 2013 USD ($)
Debt Instrument [Line Items]
Capitalized interest			$ 6,200,000	$ 3,600,000	$ 16,200,000	$ 7,800,000
Repayment of long-term debt					380,700,000	319,706,000
Financial liabilities			1,169,693,000		1,169,693,000					$ 1,513,703,000
Transfer of accounts receivable program, termination								$ 150,000,000
CMCP
Debt Instrument [Line Items]
Revolving credit facility current borrowing capacity			129,900,000		129,900,000		zł 550,000,000			63,900,000	zł 300,000,000
Revolving credit facility, amount drawn			0		0					0
Poland Program
Debt Instrument [Line Items]
Transfer of accounts receivable program limit			68,000,000		68,000,000		288,000,000			61,300,000
Advances outstanding under transfer of receivables programs			$ 24,600,000		$ 24,600,000		zł 104,000,000			26,400,000	124,000,000
2023 Notes
Debt Instrument [Line Items]
Face amount of debt												$ 330,000,000
Weighted average interest rate			4.875%		4.875%		4.875%					4.875%
Repayment of long-term debt	$ 214,100,000	$ 115,900,000
Financial liabilities			$ 0		$ 0					330,000,000
Poland Term Loan \| CMCP
Debt Instrument [Line Items]
Stand by letters of credit outstanding amount			$ 15,900,000		$ 15,900,000					1,000,000
Financial liabilities										32,400,000	zł 152,400,000
Poland Term Loan \| Revolving credit facility
Debt Instrument [Line Items]
Weighted average interest rate			0.00%		0.00%		0.00%
Financial liabilities			$ 0		$ 0					32,439,000
Line of Credit \| Revolving credit facility \| Credit Agreement Maturing October 2027
Debt Instrument [Line Items]
Revolving credit facility current borrowing capacity									$ 600,000,000
Maximum borrowing capacity									850,000,000
Revolving credit facility, amount drawn			0	$ 0	0	$ 0
Line of Credit \| Revolving credit facility \| Credit Agreement Maturing March 2026
Debt Instrument [Line Items]
Revolving credit facility current borrowing capacity									400,000,000
Line of Credit \| Secured Debt \| Credit Agreement Maturing October 2027
Debt Instrument [Line Items]
Face amount of debt									200,000,000
Revolving credit facility, amount drawn			0		0
Standby Letters of Credit
Debt Instrument [Line Items]
Stand by letters of credit outstanding amount			$ 900,000		$ 900,000					$ 1,400,000
Standby Letters of Credit \| Revolving credit facility \| Credit Agreement Maturing October 2027
Debt Instrument [Line Items]
Revolving credit facility current borrowing capacity									$ 50,000,000