Disposal Group, Including Discontinued Operations, Impairment

No definition available.

Name:	cmc_DisposalGroupIncludingDiscontinuedOperationsImpairment
Namespace Prefix:	cmc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- 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

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Data Type:	xbrli:integerItemType
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Period Type:	duration

- Definition

Amount of foreign currency translation gain (loss) in the disposal group, including discontinued operation, recognized in the statement of income as a result of the sale or complete or substantially complete liquidation of an investment in a foreign entity.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 830
-SubTopic 30
-Section 45
-Paragraph 20
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=109240241&loc=d3e32211-110900

+ Details

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- 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

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Balance Type:	na
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- Definition

The aggregate amount of write-downs for impairments recognized during the period for long lived assets held for use (including those held for disposal by means other than sale).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3602-108585

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 360
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=109226691&loc=d3e2921-110230

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 958
-SubTopic 220
-Section 45
-Paragraph 11
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=114873921&loc=SL114875236-224282

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 360
-SubTopic 10
-Section 45
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=109226348&loc=d3e2420-110228

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

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- Details

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- Details

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FAIR VALUE (Narrative) (Details) $ in Millions	3 Months Ended	12 Months Ended
FAIR VALUE (Narrative) (Details) $ in Millions	Aug. 31, 2017 USD ($)	Aug. 31, 2018 USD ($) levels	Aug. 31, 2017 USD ($)	Aug. 31, 2016 USD ($)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Number of fair value hierarchy \| levels		3
Nonrecurring impairment charge		$ 2.1	$ 4.2	$ 15.8
Americas Recycling
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impairment of long-lived assets	$ 38.9
Structural Steel Fabrication Operations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Nonrecurring impairment charge		(13.7)
Australian Steel Trading Business
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Foreign currency translation loss		$ (2.1)	$ (4.2)	$ (15.8)