Date at which the Company may redeem some or all of the Notes at a redemption premium.

No definition available.

Name:	cas_DateOfRedemption
Namespace Prefix:	cas_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage of the aggregate principal amount of the Secured Notes that may be redeemed before a certain specified date.

+ References

No definition available.

+ Details

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

- Definition

As of the balance sheet date, the amount of secured debt offered to be purchased as a result of excess cash flow as required by the indenture agreement.

+ References

No definition available.

+ Details

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

- Definition

Redemption Price on Principal Amount, Percentage, Upon Certain Asset Sales

+ References

No definition available.

+ Details

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

- Definition

Redemption Price, Percentage

+ References

No definition available.

+ Details

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

- Definition

Redemption Price, Stated as a Percentage of Principal, Percentage, Change of Control

+ References

No definition available.

+ Details

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

- Definition

The amount of the redemption price in percentage in the event of excess cash flow.

+ References

No definition available.

+ Details

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

- Definition

Amount of outstanding principal due for the Senior Secured Notes at the maturity date, before deducting unamortized discount.

+ References

No definition available.

+ Details

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

- Definition

Timeframe after the end of each fiscal year that the Company must make an offer to purchase New Secured Notes with certain of its excess cash flow for such fiscal year. Days After Fiscal Year End

+ References

No definition available.

+ Details

Name:	cas_TimeframeAfterEndOfEachFiscalYearThatCompanyMustMakeOfferToPurchaseNewSecuredNotesWithCertainOfItsExcessCashFlowForSuchFiscalYearDaysAfterFiscalYearEnd
Namespace Prefix:	cas_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Interest rate stated in the contractual debt agreement.

+ References

+ Details

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

- Details

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

- Definition

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

+ References

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

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 129

-Paragraph 2, 4

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

+ Details

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

- Definition

The amount of cash paid for interest during the period.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 50

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6367179&loc=d3e4297-108586

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 95

-Paragraph 29

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 25

-Subparagraph (e)

-URI http://asc.fasb.org/extlink&oid=6943989&loc=d3e3536-108585

+ Details

Name:	us-gaap_InterestPaid
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Debt Secured Notes (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended											12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2012 New Revolving Credit Facility [Member]	Dec. 31, 2012 Secured Notes Due in 2016 - New [Member]	Jun. 12, 2012 Secured Notes Due in 2016 - New [Member]	Dec. 31, 2011 Secured Notes Due in 2016 - New [Member]	Jun. 12, 2012 Secured Notes Due in 2016 - Old [Member]	Dec. 31, 2011 Secured Notes Due in 2016 - Old [Member]	Dec. 31, 2012 Senior Secured Notes Due in 2016 [Member]	Dec. 31, 2011 Senior Secured Notes Due in 2016 [Member]	Dec. 31, 2012 Indenture Agreement, December 15 2011	Dec. 31, 2012 Redemption Date Range 1 [Member] Secured Notes Due in 2016 - New [Member]	Dec. 31, 2012 Redemption Date Range 2 [Member] Secured Notes Due in 2016 - New [Member]	Dec. 31, 2012 Redemption Date Range 3 [Member] Secured Notes Due in 2016 - New [Member]
Debt Instrument [Line Items]
Aggregate principal amount issued	$ 225,000	$ 225,000					$ 225,000		$ 225,000		$ 225,000
Stated interest rate on debt					12.75%	12.75%		12.75%		12.75%		7.00%
Maturity date				Dec. 15, 2015	Dec. 15, 2016							Dec. 15, 2017
Date of redemption					On or after December 15, 2014							On or after December 20, 2015
Redemption percentage after disclosed date													112.75%	106.375%	100.00%
Maximum redemption of secured notes, states as a percentage													35.00%
Redemption price stated as a percentage of principal					101.00%
Redemption price on principal amount, percentage, upon certain asset sales					100.00%
Offer to purchase secured notes with certain of its excess cash flow					95 days
Requirement to purchase secured notes with excess cash flows as a percentage of outstanding principal					103.00%
Interest	34,051	7,234	4,392		28,688							4,025
Excess Cash Flow Per Seniot Secured Note Agreement					$ 17,000