XML 78 R39.htm IDEA: XBRL DOCUMENT
v3.20.1

REVENUE RECOGNITION - Revenue Recognition Method (Details) - Americas Fabrication | 3 Months Ended | 6 Months Ended
--- | --- | ---
Feb. 29, 2020 | Feb. 29, 2020
Recognized as Amounts are Billed |  |
Disaggregation of Revenue [Line Items] |  |
Contract as percent of total segment revenue (percent) | 48.00% | 50.00%
Fabricated Product and Installation Services | Recognized over Time |  |
Disaggregation of Revenue [Line Items] |  |
Contract as percent of total segment revenue (percent) | 27.00% | 26.00%
Fabricated Product without Installation Services | Recognized over Time |  |
Disaggregation of Revenue [Line Items] |  |
Contract as percent of total segment revenue (percent) | 25.00% | 24.00%

X
- Definition Contract with Customer, Contract as Percent of Total Revenue + References No definition available. + Details
Name: | cmc_ContractwithCustomerContractasPercentofTotalRevenue
Namespace Prefix: | cmc_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- 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_DisaggregationOfRevenueLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_StatementBusinessSegmentsAxis=cmc_AmericasFabricationMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_TimingOfTransferOfGoodOrServiceAxis=us-gaap_TransferredAtPointInTimeMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_ProductOrServiceAxis=cmc_FabricatedProductandInstallationServicesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_TimingOfTransferOfGoodOrServiceAxis=us-gaap_TransferredOverTimeMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_ProductOrServiceAxis=cmc_FabricatedProductwithoutInstallationServicesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |