v2.4.0.6

Summary of Share Based Compensation Option Nonvested (Detail) (USD $)	6 Months Ended
	Jun. 30, 2012
Shares - Nonvested
Granted
Forfeited	110,000
Non Vested Stock Options
Shares - Nonvested
Beginning Balance	69,200
Granted
Vested	(69,200)
Forfeited
Ending Balance	0
Weighted Average Grant-Date Fair Value
Beginning Balance	0.73
Granted
Vested	0.73
Forfeited
Ending Balance	0

X

- Definition

Share Based Compensation Arrangement by Share Based Payment Award, Nonvested Options, Forfeited in Period, Weighted Average Grant Date Fair Value

+ References

No definition available.

+ Details

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Namespace Prefix:	crv_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Share Based Compensation Arrangement by Share Based Payment Award, Nonvested Options, Granted in Period, Weighted Average Grant Date Fair Value

+ References

No definition available.

+ Details

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Namespace Prefix:	crv_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Share Based Compensation Arrangement by Share Based Payment Award, Nonvested Options, Vested in Period, Weighted Average Grant Date Fair Value

+ References

No definition available.

+ Details

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Namespace Prefix:	crv_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration

X

- Details

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Namespace Prefix:	crv_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Share based Compensation Arrangement by Share based Payment Award, Options Nonvested, Weighted Average Grant Date Fair Value

+ References

No definition available.

+ Details

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Namespace Prefix:	crv_
Data Type:	num:perShareItemType
Balance Type:	na
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X

- Details

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Namespace Prefix:	crv_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number, Nonvested

+ References

No definition available.

+ Details

Name:	crv_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingNumberNonvested
Namespace Prefix:	crv_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

X

- Definition

Share Based Compensation Arrangement by Share Based Payment Award, Options, Vested in Period

+ References

No definition available.

+ Details

Name:	crv_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedInPeriod
Namespace Prefix:	crv_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

X

- Definition

The number of shares under options that were cancelled during the reporting period as a result of occurrence of a terminating event specified in contractual agreements pertaining to the stock option plan.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)(1)(iv)(3)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901



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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 123R

-Paragraph A240

-Subparagraph b(1)(f)

-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

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

X

- Definition

Net number of share options (or share units) granted during the period.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)(1)(iv)(1)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901



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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 123R

-Paragraph A240

-Subparagraph b(1)(d)

-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

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
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