Long-Term Debt (6.0% Senior Priority Secured Notes) (Details) (USD $)	0 Months Ended
Jun. 26, 2014	Dec. 27, 2014
Senior notes [Member] \| 6.000% senior secured priority notes due 2019 [Member]
Debt Instrument [Line Items]
Debt instrument, face amount	540,000,000
Debt interest rate (percent)	6.00%	6.00%
Debt redemption price, change of control (percentage)	101.00%
Senior notes [Member] \| 6.000% senior secured priority notes due 2019 [Member] \| Prior to August 1, 2017 [Member]
Debt Instrument [Line Items]
Debt redemption price (percentage)	106.00%
Debt redemption price, maximum percentage of principal amount redeemable (percent)	35.00%
Senior notes [Member] \| 6.000% senior secured priority notes due 2019 [Member] \| Between August 1, 2017, and February 1, 2019 [Member]
Debt Instrument [Line Items]
Debt redemption price (percentage)	100.00%
Debt redemption price, minimum make-whole premium (percentage)	1.00%
Senior notes [Member] \| 6.000% senior secured priority notes due 2019 [Member] \| On or After February 1, 2019 [Member]
Debt Instrument [Line Items]
Debt redemption price (percentage)	100.00%
Line of credit [Member] \| ABL Facility due 2017 [Member]
Debt Instrument [Line Items]
Credit facility, borrowing capacity		230,000,000

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

No definition available.

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- Definition

Debt Instrument, Redemption Price, Percentage, Change of Control

+ References

No definition available.

+ Details

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- Definition

Debt Instrument, Redemption Price, Premium, Percentage

+ References

No definition available.

+ Details

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Namespace Prefix:	cvo_
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Balance Type:	na
Period Type:	duration

- 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

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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

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- Details

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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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- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the 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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