XML 110 R101.htm IDEA: XBRL DOCUMENT
v2.4.0.8

Fair Value Measurements Text Tag (Details) | 12 Months Ended
--- | ---
Mar. 31, 2013
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |
Percent of Total Assets Level 3 | 0.10%

X
- Definition Percent of Total Assets Level 3 + References No definition available. + Details
Name: | carv_PercentOfTotalAssetsLevel3
Namespace Prefix: | carv_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

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