Line of Credit - Additional Information (Detail) (USD $)	12 Months Ended
Mar. 31, 2015
Debt Disclosure [Abstract]
Credit facility with borrowing capacity	$ 10,000,000
Debt instrument, basis spread on variable rate	1.50%
Fluctuating rate determined by financial institution	Fluctuating rate determined by the financial institution to be 1.50% above the daily one-month LIBOR rate.
Debt to tangible net worth not greater than	Debt to tangible net worth not greater than 1.25:1
Current assets to liabilities ratio	1.25
Debt to tangible net worth	125.00%
Amount borrowed under line of credit	618,000us-gaap_LineOfCredit
Line of credit paid off date	Apr. 01, 2015
Letters of credit in aggregate amount	$ 4,500,000
Renewed credit agreement expiration period	September 2015

Debt to tangible net worth not greater than 1.25:1

No definition available.

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- Definition

Fluctuating rate determined by the financial institution to be 1.50% above the daily one-month LIBOR rate.

+ References

No definition available.

+ Details

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Period Type:	duration

- Definition

Expiration of line of credit.

+ References

No definition available.

+ Details

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

- Definition

Debt to tangible net worth not greater than 1.25:1

+ References

No definition available.

+ Details

Name:	crvl_LineOfCreditFacilityCurrentAssetsToLiabilitiesRatio
Namespace Prefix:	crvl_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	instant

- Definition

Debt to tangible net worth not greater than 1.25:1

+ References

No definition available.

+ Details

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Namespace Prefix:	crvl_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Line of credit facility repayment date.

+ References

No definition available.

+ Details

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Namespace Prefix:	crvl_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Details

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Data Type:	xbrli:stringItemType
Balance Type:	na
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- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.

+ References

No definition available.

+ Details

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

- Definition

The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-03.16)

-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 19, 20, 22

-Article 5

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.7-03.16)

-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

+ Details

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

- Definition

Amount of current borrowing capacity under the credit facility considering any current restrictions on the amount that could be borrowed (for example, borrowings may be limited by the amount of current assets), but without considering any amounts currently outstanding under the facility.

+ 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 210.5-02.19(b),22(b))

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

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 19, 22

-Article 5

+ Details

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