v2.4.1.9

Commitments and Contingencies - Additional Information (Detail) (USD $) | 12 Months Ended
--- | ---
Dec. 31, 2014 | Dec. 31, 2013 | Dec. 31, 2012
Operating Leased Assets [Line Items] |  |  |
Rent expenses | $ 3,670,000 us-gaap_OperatingLeasesRentExpenseNet | $ 3,759,000 us-gaap_OperatingLeasesRentExpenseNet | $ 3,938,000 us-gaap_OperatingLeasesRentExpenseNet
Office and Warehouse |  |  |
Operating Leased Assets [Line Items] |  |  |
Lease, expired period | 12 years |  |

X
- Definition Operating Lease Expiration Period + References No definition available. + Details
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Namespace Prefix: | crv_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_OperatingLeasedAssetsLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Rental expense for the reporting period incurred under operating leases, including minimum and any contingent rent expense, net of related sublease income. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 840 -SubTopic 20 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6453985&loc=d3e41499-112717 + Details
Name: | us-gaap_OperatingLeasesRentExpenseNet
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Details
Name: | us-gaap_PropertyPlantAndEquipmentByTypeAxis=crv_OfficeFacilitiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |