Revenue - Performance Obligations (Details) $ in Millions	Mar. 31, 2019 USD ($)	Dec. 31, 2018
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Nine months ended December 31, 2019	$ 2.0
2020	2.6
2021	2.5
2022	2.6
2023	2.5
Thereafter	27.1
Total	$ 39.3
Revenue, Remaining Performance Obligation, Percentage	80.00%
Indefeasible Right of Use, Maximum, in Years		30

The contract term of certain indefeasible right of use contracts, in years.

No definition available.

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- Definition

The amount of revenue that will be recognized in the remainder of fiscal year allocated to performance obligations.

+ References

No definition available.

+ Details

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- Definition

The amount of revenue that will be recognized thereafter allocated to performance obligation.

+ References

No definition available.

+ Details

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- Definition

The amount of revenue that will be recognized in year 5 allocated to performance obligations.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
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- Definition

The amount of revenue that will be recognized in year four allocated to performance obligations.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
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- Definition

The amount of revenue that will be recognized in year three allocated to performance obligations.

+ References

No definition available.

+ Details

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Namespace Prefix:	cbb_
Data Type:	xbrli:monetaryItemType
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Period Type:	instant

- Definition

The amount of revenue that will be recognized in year two allocated to performance obligations.

+ References

No definition available.

+ Details

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Namespace Prefix:	cbb_
Data Type:	xbrli:monetaryItemType
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- Definition

Amount of transaction price allocated to performance obligation that has not been recognized as revenue.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 13
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=109196051&loc=SL49130556-203045

+ Details

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Balance Type:	credit
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

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- Definition

Percentage of remaining performance obligation to total remaining performance obligation not recognized as revenue.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 13
-Subparagraph (b)(1)
-URI http://asc.fasb.org/extlink&oid=109196051&loc=SL49130556-203045

+ Details

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