Long-Term Debt (8.5% Junior Priority Secured Notes) (Details) (Junior subordinated debt [Member], 8.500% junior secured priority notes due 2022 [Member], USD $)	0 Months Ended
Jun. 26, 2014	Dec. 27, 2014
Debt Instrument [Line Items]
Debt instrument, face amount	250,000,000us-gaap_DebtInstrumentFaceAmount
Debt interest rate (percent)	8.50%	8.50%
Debt redemption price, maximum percentage of principal amount redeemable (percent)	35.00%
Debt redemption price, change of control (percentage)	101.00%
Prior to September 15, 2017 [Member]
Debt Instrument [Line Items]
Debt redemption price (percentage)	108.50%
September 15, 2017 through September 14, 2018 [Member]
Debt Instrument [Line Items]
Debt redemption price (percentage)	106.375%
September 15, 2018 through September 14, 2019 [Member]
Debt Instrument [Line Items]
Debt redemption price (percentage)	104.25%
September 15, 2019 through September 14, 2020 [Member]
Debt Instrument [Line Items]
Debt redemption price (percentage)	102.125%
On or After September 15, 2020 [Member]
Debt Instrument [Line Items]
Debt redemption price (percentage)	100.00%

Debt Instrument, Redemption Price, Maximum Percentage of Principal Amount Redeemable

No definition available.

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Namespace Prefix:	cvo_
Data Type:	num:percentItemType
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Period Type:	instant

- Definition

Debt Instrument, Redemption Price, Percentage, Change of Control

+ References

No definition available.

+ Details

Name:	cvo_DebtInstrumentRedemptionPricePercentageChangeofControl
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 45

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6451184&loc=d3e28551-108399

Reference 2: 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=6584090&loc=d3e28878-108400

+ 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 SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 22

-Article 5

Reference 2: 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

+ Details

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

- Details

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

- Definition

Percentage price of original principal amount of debt at which debt can be redeemed by the issuer.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 470

-Section 50

-Paragraph 3

-Subparagraph e

-URI http://asc.fasb.org/extlink&oid=6479336&loc=d3e64711-112823

+ Details

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Namespace Prefix:	us-gaap_
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Balance Type:	na
Period Type:	duration