Name:	cas_EarningsBeforeInterestTaxesDepreciationAndAmortizationToFixedChargesRatio
Namespace Prefix:	cas_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	instant

The lower bound of excess revolver availability as defined in Revolving Credit Facility Agreement, under which amount the Company must retain a ratio of EBITDA to fixed charges of 1.1 to 1.0.

No definition available.

Name:	cas_ExcessAvailabilitylowerboundfixedchargecoverage
Namespace Prefix:	cas_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

The lower bound of excess revolver availability under which amount the lender has the right to take full dominion of the Company's cash collections and apply them to outstanding loans under the Revolving Credit Agreement.

No definition available.

Name:	cas_ExcessAvailabilitylowerboundlenderfulldominionovercollections
Namespace Prefix:	cas_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Lower bound percentage of excess availability to calculated borrowing base, under which percentage the Company must maintain a ratio of EBITDA to fixed charges of 1.1 to 1.0.

No definition available.

Name:	cas_Excessavailabilitypercentageofborrowingbaselowerboundfixedchargecoverage
Namespace Prefix:	cas_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

The lower bound excess availability percentage of borrowing base where the lender has the right to take full dominion of the Company's cash collections and apply them to amounts outstanding under the Revolving Credit Facility.

No definition available.

Name:	cas_Excessavailabilitypercentageofborrowingbaselowerboundlenderfulldominionovercollections
Namespace Prefix:	cas_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

Line of Credit Facility, Borrowing Capacity excluding minimum excess availability, springing covenant

No definition available.

Name:	cas_LineofCreditFacilityBorrowingCapacityexcludingminimumexcessavailabilityspringingcovenant
Namespace Prefix:	cas_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Line of Credit, Terms, Provision to Increase the Aggregate Amount of Commitments Under Certain Conditions, Amount

No definition available.

Name:	cas_LineOfCreditTermsProvisionToIncreaseAggregateAmountOfCommitmentsUnderCertainConditionsAmount
Namespace Prefix:	cas_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Details

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

Date when the debt instrument is scheduled to be fully repaid, in CCYY-MM-DD format.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 22

-Article 5

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.22(a)(2))

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Name:	us-gaap_DebtInstrumentMaturityDate
Namespace Prefix:	us-gaap_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

Weighted average interest rate of debt outstanding.

No definition available.

Name:	us-gaap_DebtWeightedAverageInterestRate
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

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.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.19(b),22(b))

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 19, 22

-Article 5

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

Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding).