Long-Term Debt (Other Debt) (Details) - Other debt including capital leases [Member] - Equipment note [Member] - USD ($) $ in Millions	Sep. 30, 2015	Sep. 16, 2013
Debt Instrument [Line Items]
Debt instrument, face amount	$ 12.5	$ 20.0
Debt interest rate (percent)	8.25%	11.00%
Debt prepayment fee (percentage)		4.00%
Debt prepayment fee, subsequent annual decrease (percentage)		1.00%
Period one [Member]
Debt Instrument [Line Items]
Debt prepayment fee (percentage)	3.00%
Period two [Member]
Debt Instrument [Line Items]
Debt prepayment fee (percentage)	2.00%
Period three [Member]
Debt Instrument [Line Items]
Debt prepayment fee (percentage)	1.00%

Debt, Prepayment Fee, Percentage

No definition available.

Name:	cvo_DebtPrepaymentFeePercentage
Namespace Prefix:	cvo_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Debt, Prepayment Fee, Subsequent Annual Decrease, Percentage

+ References

No definition available.

+ Details

Name:	cvo_DebtPrepaymentFeeSubsequentAnnualDecreasePercentage
Namespace Prefix:	cvo_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Face (par) amount of debt instrument at time of issuance.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=34725769&loc=d3e28878-108400

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6451184&loc=d3e28551-108399

+ Details

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

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ 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 210.5-02.22(a)(1))
-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 22
-Article 5

+ Details

Name:	us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

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

- Details

Name:	us-gaap_LongtermDebtTypeAxis=cvo_OtherDebtIncludingCapitalLeasesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=cvo_EquipmentnoteMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentRedemptionPeriodAxis=us-gaap_DebtInstrumentRedemptionPeriodOneMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentRedemptionPeriodAxis=us-gaap_DebtInstrumentRedemptionPeriodTwoMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentRedemptionPeriodAxis=us-gaap_DebtInstrumentRedemptionPeriodThreeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: