Derivative, Percentage of Variable Rate Receivable

No definition available.

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- Definition

Unrealized Gain (Loss) on Interest Rate Cash Flow Hedges, Net of Tax, Accumulated Other Comprehensive Income (Loss), Monthly Amortization

+ References

No definition available.

+ Details

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Namespace Prefix:	cmt_
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Balance Type:	debit
Period Type:	duration

- Definition

Unrealized Gain (Loss) on Interest Rate Cash Flow Hedges, Pretax, Accumulated Other Comprehensive Income (Loss), Monthly Amortization

+ References

No definition available.

+ Details

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Namespace Prefix:	cmt_
Data Type:	xbrli:monetaryItemType
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Period Type:	duration

- Definition

Aggregate notional amount specified by the derivative(s). Expressed as an absolute value.

+ References

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Article 12

-Section 13

-Sentence Column B

+ Details

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Namespace Prefix:	invest_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount of the increase (decrease) in fair value of the hedged item in a fair value hedge recognized in the income statement.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 25

-Section 50

-Paragraph 1

-Subparagraph (a)(1)

-URI http://asc.fasb.org/extlink&oid=6886632&loc=d3e76258-113986

+ Details

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Period Type:	duration

- Definition

Face (par) amount of debt instrument at time of issuance.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 835

-SubTopic 30

-Section 45

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6451184&loc=d3e28551-108399

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 835

-SubTopic 30

-Section 55

-Paragraph 8

-URI http://asc.fasb.org/extlink&oid=6584090&loc=d3e28878-108400

+ Details

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- Definition

The reference rate for the variable rate of the interest rate derivative, such as LIBOR or the US Treasury rate and the maturity of the reference rate used, such as three months or six months LIBOR.

+ References

No definition available.

+ Details

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- Definition

Fixed interest rate related to the interest rate derivative.

+ References

No definition available.

+ Details

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

- Definition

Fair value, after the effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets not subject to a master netting arrangement and not elected to be offset.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 825

-SubTopic 10

-Section 50

-Paragraph 10

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=28364263&loc=d3e13433-108611

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 45

-Paragraph 5

-URI http://asc.fasb.org/extlink&oid=6945355&loc=d3e41228-113958

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 825

-SubTopic 10

-Section 50

-Paragraph 15

-URI http://asc.fasb.org/extlink&oid=28364263&loc=d3e13495-108611

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 20

-Section 50

-Paragraph 3

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=20225523&loc=SL20225862-175312

Reference 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 45

-Paragraph 6

-URI http://asc.fasb.org/extlink&oid=6945355&loc=d3e41271-113958

Reference 6: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 20

-Section 55

-Paragraph 10

-URI http://asc.fasb.org/extlink&oid=28370219&loc=SL20226008-175313

+ Details

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Balance Type:	credit
Period Type:	instant

- Details

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- Definition

Variable interest rate in effect as of the balance sheet date related to the interest rate derivative.

+ References

No definition available.

+ Details

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- Definition

Description of the transactions or other events that will result in the reclassification into earnings of gains or losses reported in accumulated other comprehensive income. May include the time period over which gains or losses will be reclassified to earnings.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 30

-Section 50

-Paragraph 1

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=7668309&loc=d3e80748-113994

+ Details

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- Definition

The net gain (loss) included in earnings for the period relating to components of the gain (loss) on interest rate fair value hedging instruments excluded from the assessment of fair value hedge effectiveness.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 25

-Section 50

-Paragraph 1

-Subparagraph (a)(2)

-URI http://asc.fasb.org/extlink&oid=6886632&loc=d3e76258-113986

+ Details

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

- Definition

Amount of unrealized gain (loss) related to the increase or decrease in fair value of interest rate derivatives designated as cash flow hedging instruments, which was recorded in accumulated other comprehensive income to the extent that the cash flow hedge was determined to be effective.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 50

-Paragraph 4C

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=7476318&loc=SL5624171-113959

+ Details

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- Details

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- Details

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Namespace Prefix:
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- Details

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Namespace Prefix:
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Period Type:

Debt and Leases - Interest Rate Swaps (Details) (USD $)	12 Months Ended			0 Months Ended
Debt and Leases - Interest Rate Swaps (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2009	Mar. 31, 2009
Interest rate swaps:
Interest expense for settlements related to swaps	$ 70,000	$ 110,000	$ 170,000
Capex loan
Interest rate swaps:
Debt instrument, face amount	12,000,000
Industrial Development Revenue Bond swap agreement
Interest rate swaps:
Derivative, fixed interest rate		4.89%
Derivative, description of variable rate basis		76% of the 30-day commercial paper rate
Derivative, variable interest rate		0.10%
Description of reclassification of cash flow hedge gain (loss)		The pre-tax loss previously recognized in Accumulated Other Comprehensive Income (Loss), totaling $200,000 as of December 31, 2009, was amortized as an increase to interest expense of $5,000 per month, or $3,000 net of tax, over the remaining term of the interest rate swap agreement.
Industrial Development Revenue Bond swap agreement \| Interest rate swap \| Cash flow hedging \| Designated as hedging instrument
Interest rate swaps:
Percentage of variable rate receivable				76.00%
Derivative, description of variable rate basis				30-day commercial paper rate
Pre-tax loss previously recognized in Accumulated Other Comprehensive Income				200,000
Pre-tax loss previously recognized in Accumulated Other Comprehensive Income, monthly amortization amount				5,000
Pre-tax loss previously recognized in Accumulated Other Comprehensive Income, monthly amortization amount, net of tax				3,000
Capex loan swap agreement
Interest rate swaps:
Derivative, fixed interest rate	2.295%
Derivative, description of variable rate basis	LIBOR
Description of reclassification of cash flow hedge gain (loss)	The pre-tax loss previously recognized in Accumulated Other Comprehensive Income (Loss), totaling $146,000 as of March 31, 2009, is being amortized as an increase to interest expense of $2,000 per month, or $1,000 net of tax, over the remaining term of the interest rate swap agreement.
Derivatives not designated as hedging instruments, interest rate swap liabilities	37,000	103,000
Interest income (loss) for mark-to-market adjustment of swap fair value	(66,000)	102,000	74,000
Derivative, Notional Amount	2,428,000	4,143,000
Capex loan swap agreement \| Interest rate swap \| Cash flow hedging \| Designated as hedging instrument
Interest rate swaps:
Pre-tax loss previously recognized in Accumulated Other Comprehensive Income					146,000
Pre-tax loss previously recognized in Accumulated Other Comprehensive Income, monthly amortization amount					2,000
Pre-tax loss previously recognized in Accumulated Other Comprehensive Income, monthly amortization amount, net of tax					$ 1,000