v2.4.1.9

Summary of Operations by Geographic Area (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Segment Reporting Information [Line Items]
Net sales to external customers	$ 22,326us-gaap_SalesRevenueNet	$ 34,821us-gaap_SalesRevenueNet	$ 36,797us-gaap_SalesRevenueNet	$ 24,855us-gaap_SalesRevenueNet	$ 19,875us-gaap_SalesRevenueNet	$ 33,101us-gaap_SalesRevenueNet	$ 35,565us-gaap_SalesRevenueNet	$ 25,397us-gaap_SalesRevenueNet	$ 118,799us-gaap_SalesRevenueNet	$ 113,938us-gaap_SalesRevenueNet	$ 113,521us-gaap_SalesRevenueNet
Operating income (loss)									79us-gaap_OperatingIncomeLoss	62us-gaap_OperatingIncomeLoss	(2,133)us-gaap_OperatingIncomeLoss
Assets	49,767us-gaap_Assets				46,244us-gaap_Assets				49,767us-gaap_Assets	46,244us-gaap_Assets
UNITED STATES
Segment Reporting Information [Line Items]
Net sales to external customers									92,686us-gaap_SalesRevenueNet / us-gaap_StatementGeographicalAxis = country_US	87,504us-gaap_SalesRevenueNet / us-gaap_StatementGeographicalAxis = country_US	85,374us-gaap_SalesRevenueNet / us-gaap_StatementGeographicalAxis = country_US
Operating income (loss)									1,289us-gaap_OperatingIncomeLoss / us-gaap_StatementGeographicalAxis = country_US	1,085us-gaap_OperatingIncomeLoss / us-gaap_StatementGeographicalAxis = country_US	(459)us-gaap_OperatingIncomeLoss / us-gaap_StatementGeographicalAxis = country_US
Assets	40,819us-gaap_Assets / us-gaap_StatementGeographicalAxis = country_US				36,339us-gaap_Assets / us-gaap_StatementGeographicalAxis = country_US				40,819us-gaap_Assets / us-gaap_StatementGeographicalAxis = country_US	36,339us-gaap_Assets / us-gaap_StatementGeographicalAxis = country_US	38,341us-gaap_Assets / us-gaap_StatementGeographicalAxis = country_US
CANADA
Segment Reporting Information [Line Items]
Net sales to external customers									26,113us-gaap_SalesRevenueNet / us-gaap_StatementGeographicalAxis = country_CA	26,434us-gaap_SalesRevenueNet / us-gaap_StatementGeographicalAxis = country_CA	28,147us-gaap_SalesRevenueNet / us-gaap_StatementGeographicalAxis = country_CA
Operating income (loss)									(1,195)us-gaap_OperatingIncomeLoss / us-gaap_StatementGeographicalAxis = country_CA	(1,122)us-gaap_OperatingIncomeLoss / us-gaap_StatementGeographicalAxis = country_CA	(1,607)us-gaap_OperatingIncomeLoss / us-gaap_StatementGeographicalAxis = country_CA
Assets	8,703us-gaap_Assets / us-gaap_StatementGeographicalAxis = country_CA				9,554us-gaap_Assets / us-gaap_StatementGeographicalAxis = country_CA				8,703us-gaap_Assets / us-gaap_StatementGeographicalAxis = country_CA	9,554us-gaap_Assets / us-gaap_StatementGeographicalAxis = country_CA	11,009us-gaap_Assets / us-gaap_StatementGeographicalAxis = country_CA
Other Countries
Segment Reporting Information [Line Items]
Operating income (loss)									(15)us-gaap_OperatingIncomeLoss / us-gaap_StatementGeographicalAxis = crv_OtherCountriesMember	99us-gaap_OperatingIncomeLoss / us-gaap_StatementGeographicalAxis = crv_OtherCountriesMember	(67)us-gaap_OperatingIncomeLoss / us-gaap_StatementGeographicalAxis = crv_OtherCountriesMember
Assets	$ 245us-gaap_Assets / us-gaap_StatementGeographicalAxis = crv_OtherCountriesMember				$ 351us-gaap_Assets / us-gaap_StatementGeographicalAxis = crv_OtherCountriesMember				$ 245us-gaap_Assets / us-gaap_StatementGeographicalAxis = crv_OtherCountriesMember	$ 351us-gaap_Assets / us-gaap_StatementGeographicalAxis = crv_OtherCountriesMember	$ 309us-gaap_Assets / us-gaap_StatementGeographicalAxis = crv_OtherCountriesMember

X

- Definition

Sum of the carrying amounts as of the balance sheet date of all assets that are recognized. Assets are probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

+ 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 210.5-02.18)

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



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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

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



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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 12

-Article 7



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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 18

-Article 5

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

The net result for the period of deducting operating expenses from operating revenues.

+ References

No definition available.

+ Details

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

X

- Definition

Total revenue from sale of goods and services rendered during the reporting period, in the normal course of business, reduced by sales returns and allowances, and sales discounts.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.1)

-URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688



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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 1

-Article 5

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X

- Details

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- Details

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X

- Details

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- Details

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