Consolidated Subsidiary, Ownership Percentage

No definition available.

Name:	cas_ConsolidatedSubsidiaryOwnershipPercentage
Namespace Prefix:	cas_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The percentage of excess cash flow which must be used to redeem New Secured Notes due December 2018, per the terms of the indenture agreement.

+ References

No definition available.

+ Details

Name:	cas_DebtInstrumentExcessCashFlowPercentage
Namespace Prefix:	cas_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The costs recognized as expense in the period for consent and other third party fees incurred in connection with a debt restructuring.

+ References

No definition available.

+ Details

Name:	cas_DebtRestructuringCosts
Namespace Prefix:	cas_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Special Redemption, percent penalty applied to outstanding principle if company fails to meet special redemption provisions as defined under New Secured Notes indenture agreement.

+ References

No definition available.

+ Details

Name:	cas_PercentPenaltySpecialRedemptionProvision
Namespace Prefix:	cas_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- 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

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

+ References

No definition available.

+ Details

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

- Definition

Redemption Price, Stated as a Percentage of Principal, Upon Certain Asset Sales

+ References

No definition available.

+ Details

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

- Definition

The upper bound of the amount of New Secured Notes due December 2018 to be purchased with excess cash flow, as defined by the indenture agreement, at respective excess cash flow percentage.

+ References

No definition available.

+ Details

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

- Definition

The amount of the aggregate principal amount of the New Secured Notes that the Company must redeem on one or more occasions prior to October 31, 2016 using cash available to the Company and/or net proceeds from sales of assets of the Company or a Restricted Subsidiary outside the normal course of business.

+ References

No definition available.

+ Details

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

- Definition

The maturity date of the New Secured Notes if the Special Redemption Condition is not met.

+ References

No definition available.

+ Details

Name:	cas_SpecialRedemptionConditionMaturityDate
Namespace Prefix:	cas_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- 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

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

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 210.5-02.22(a)(1))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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

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

- Definition

Percentage price of original principal amount of debt at which debt can be redeemed by the issuer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 470
-Section 50
-Paragraph 3
-Subparagraph e
-URI http://asc.fasb.org/extlink&oid=6479336&loc=d3e64711-112823

+ Details

Name:	us-gaap_DebtInstrumentRedemptionPricePercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Including the current and noncurrent portions, carrying value as of the balance sheet date of Notes with the highest claim on the assets of the issuer in case of bankruptcy or liquidation (with maturities initially due after one year or beyond the operating cycle if longer). Senior note holders are paid off in full before any payments are made to junior note holders.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03.16(a))
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.16)
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

+ Details

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

- Details

Name:	us-gaap_DebtInstrumentAxis=cas_SeniorSecuredNotesDuein2018Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=cas_SeniorSecuredNotesDueIn2016Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementGeographicalAxis=cas_DomesticSubsidiariesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RangeAxis=us-gaap_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RangeAxis=us-gaap_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RangeAxis=cas_A0ExcessCashFlowMemberMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RangeAxis=cas_A75ExcessCashFlowMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RangeAxis=cas_A50ExcessCashFlowMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RangeAxis=cas_A25ExcessCashFlowMember
Namespace Prefix:
Data Type:	na
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Period Type:

Debt Secured Notes (Details) - USD ($) $ in Thousands	3 Months Ended
Debt Secured Notes (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015
Debt Instrument [Line Items]
Debt Restructuring Costs	$ 7,075	$ 0
Percent, Penalty Special Redemption Provision	4.00%
Special Redemption Condition, Maturity Date	Sep. 14, 2017
Senior Secured Notes Due in 2018 [Member]
Debt Instrument [Line Items]
Senior Notes	$ 203,319		$ 203,319
Debt Instrument, Interest Rate, Stated Percentage	12.75%
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	95 days
Debt Instrument, Redemption Price, Percentage	100.00%
Redemption Price, Stated as a Percentage of Principal, Change of Control	101.00%
Redemption Price, Stated as a Percentage of Principal, Upon Certain Asset Sales	100.00%
Senior Secured Notes Due in 2016 [Member]
Debt Instrument [Line Items]
Senior Notes	$ 6,681		$ 6,681
Debt Instrument, Interest Rate, Stated Percentage	12.75%
Debt Instrument, Redemption Price, Percentage	100.00%
Domestic Subsidiaries [Member] \| Senior Secured Notes Due in 2018 [Member]
Debt Instrument [Line Items]
Consolidated Subsidiary, Ownership Percentage	100.00%
Minimum
Debt Instrument [Line Items]
Special Redemption, Amount	$ 27,500
Maximum [Member]
Debt Instrument [Line Items]
Special Redemption, Amount	$ 40,000
0% Excess Cash Flow [Member] [Member]
Debt Instrument [Line Items]
Redemption Price, Stated as a Percentage of Principal, Percentage, Excess Cash Flow	103.00%
Debt Instrument, Excess Cash Flow, Percentage	0.00%
75% Excess Cash Flow [Member]
Debt Instrument [Line Items]
Debt Instrument, Excess Cash Flow, Percentage	75.00%
Secured Notes to be Purchased with Excess Cash Flow	$ 50,000
50% Excess Cash Flow [Member]
Debt Instrument [Line Items]
Debt Instrument, Excess Cash Flow, Percentage	50.00%
Secured Notes to be Purchased with Excess Cash Flow	$ 75,000
25% Excess Cash Flow [Member]
Debt Instrument [Line Items]
Debt Instrument, Excess Cash Flow, Percentage	25.00%
Secured Notes to be Purchased with Excess Cash Flow	$ 100,000