Superalloy Powders Technical Assistance and Powder Supply Agreements (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended	9 Months Ended
Sep. 30, 2014	Jun. 30, 2014
Superalloy powders technical assistance and powder supply agreements
Up-front license fee asset	$ 13.0	$ 13.0
Up-front license fee paid	9.8	9.8
Other assets
Superalloy powders technical assistance and powder supply agreements
Up-front license fee asset	13.0	13.0
Accrued liability
Superalloy powders technical assistance and powder supply agreements
Up-front license fee payable	3.2	3.2
Technical assistance agreement and a long-term powder supply agreement \| UTC
Superalloy powders technical assistance and powder supply agreements
Term for minimum guaranteed purchase quantities of specified materials	12 years	12 years
Technical assistance agreement and a long-term powder supply agreement \| UTC \| Maximum
Superalloy powders technical assistance and powder supply agreements
Superalloy powder supply term	20 years	20 years
Technical assistance agreement and a long-term powder supply agreement \| UTC \| Estimated
Superalloy powders technical assistance and powder supply agreements
Superalloy powder facility construction period	18 months	18 months
Superalloy powder facility construction costs	$ 30

Represents the plant construction period.

No definition available.

Name:	crs_PlantConstructionPeriod
Namespace Prefix:	crs_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

Amount of costs which are directly related to the specified activities to build the plant.

No definition available.

Represents the supply arrangement term for the minimum guaranteed purchase quantities of the specified materials.

No definition available.

Name:	crs_SupplyArrangementMinimumGuaranteedPurchaseQuantityTerm
Namespace Prefix:	crs_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

Represents the term of the supply arrangement.

No definition available.

Name:	crs_TechnicalAssistanceAndMaterialSupplyAgreementLineItems
Namespace Prefix:	crs_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Amount of up-front license fee asset according to the terms of the technology licensing agreement.

No definition available.

Name:	crs_UpFrontLicenseFeeAsset
Namespace Prefix:	crs_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Represents the amount of up-front license fee paid according to the terms of the technology licensing agreement.

No definition available.

Amount of up-front license fee payable according to the terms of the technology licensing agreement.

No definition available.

Name:	crs_UpFrontLicenseFeePayable
Namespace Prefix:	crs_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant