XML 78 R67.htm IDEA: XBRL DOCUMENT
v3.19.2

FAIR VALUE (Narrative) (Details) $ in Millions | 3 Months Ended | 9 Months Ended
--- | --- | ---
May 31, 2018 USD ($) | May 31, 2019 levels | May 31, 2018 USD ($)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Number of fair value hierarchy | levels |  | 3 |
Structural Steel Fabrication Operations |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Nonrecurring impairment charge | $ | $ 0.9 |  | $ 13.0

X
- Definition Disposal Group, Including Discontinued Operations, Impairment + References No definition available. + Details
Name: | cmc_DisposalGroupIncludingDiscontinuedOperationsImpairment
Namespace Prefix: | cmc_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition This represents number of levels used to prioritize the inputs to valuation techniques used to measure fair value. The fair value hierarchy gives the highest priority to quoted prices (unadjusted) in active markets for identical assets or liabilities (Level 1), inputs other than quoted prices included within Level 1 that are observable for the asset or liability, either directly or indirectly (Level 2), and the lowest priority to unobservable inputs (Level 3). Where the quoted price in an active market for the identical liability is not available, the Level 1 input is the quoted price of an identical liability when traded as an asset. + References No definition available. + Details
Name: | cmc_NumberofFairValueHierarchy
Namespace Prefix: | cmc_
Data Type: | xbrli:integerItemType
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_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis=cmc_StructuralSteelFabricationOperationsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |