v3.2.0.727

Commitments - Additional Information (Detail)	6 Months Ended
	Jun. 30, 2015
Office and Warehouse
Operating Leased Assets [Line Items]
Lease, expiration period	10 years

X

- Definition

Operating Lease Expiration Period

+ References

No definition available.

+ Details

Name:	crv_OperatingLeaseExpirationPeriod
Namespace Prefix:	crv_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

X

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

X

- Details

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