Debt amortization percentage.

No definition available.

Name:	csal_DebtAmortizationPercentage
Namespace Prefix:	csal_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Debt instrument basis spread on floor rate.

+ References

No definition available.

+ Details

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Namespace Prefix:	csal_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Debt instrument issue price percentage.

+ References

No definition available.

+ Details

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Namespace Prefix:	csal_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Debt instruments maturity period.

+ References

No definition available.

+ Details

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Namespace Prefix:	csal_
Data Type:	xbrli:gYearMonthItemType
Balance Type:	na
Period Type:	duration

- Definition

Distribution made to limited liability company member percentage distribution.

+ References

No definition available.

+ Details

Name:	csal_DistributionMadeToLimitedLiabilityCompanyMemberPercentageDistribution
Namespace Prefix:	csal_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Leverage ratio.

+ References

No definition available.

+ Details

Name:	csal_LeverageRatio
Namespace Prefix:	csal_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Secured leverage ratio.

+ References

No definition available.

+ Details

Name:	csal_SecuredLeverageRatio
Namespace Prefix:	csal_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Term loan issue price percentage of par.

+ References

No definition available.

+ Details

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

- Definition

Aggregate notional amount specified by the derivative(s). Expressed as an absolute value.

+ References

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Article 12

-Section 13

-Sentence Column B

+ Details

Name:	invest_DerivativeNotionalAmount
Namespace Prefix:	invest_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	instant

- Definition

Face amount or stated value per share of common stock.

+ 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 210.5-02.29)

-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 30

-Article 5

+ Details

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Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant

- Definition

Total number of common shares of an entity that have been sold or granted to shareholders (includes common shares that were issued, repurchased and remain in the treasury). These shares represent capital invested by the firm's shareholders and owners, and may be all or only a portion of the number of shares authorized. Shares issued include shares outstanding and shares held in the treasury.

+ References

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

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

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
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

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-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

+ Details

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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

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

- Definition

Date when the debt instrument is scheduled to be fully repaid, in CCYY-MM-DD format.

+ 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)(2))

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

+ Details

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

- Definition

Average fixed interest rate related to the group of interest rate derivatives.

+ References

No definition available.

+ Details

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

- Definition

Low end of the range of variable interest rates when a range is presented for a group of interest rate derivatives.

+ References

No definition available.

+ Details

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

- Definition

Date the derivative contract matures, in CCYY-MM-DD format.

+ References

No definition available.

+ Details

Name:	us-gaap_DerivativeMaturityDates
Namespace Prefix:	us-gaap_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- 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

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

- Definition

The equity interest of noncontrolling shareholders, partners or other equity holders in consolidated entity.

+ References

No definition available.

+ Details

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

- Definition

The value of an asset or business acquired in a noncash (or part noncash) acquisition. Noncash is defined as information about all investing and financing activities of an enterprise during a period that affect recognized assets or liabilities but that do not result in cash receipts or cash payments in the period. "Part noncash" refers to that portion of the transaction not resulting in cash receipts or cash payments in the period.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 50

-Paragraph 5

-URI http://asc.fasb.org/extlink&oid=6367179&loc=d3e4332-108586

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 50

-Paragraph 4

-URI http://asc.fasb.org/extlink&oid=6367179&loc=d3e4313-108586

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 50

-Paragraph 3

-URI http://asc.fasb.org/extlink&oid=6367179&loc=d3e4304-108586

+ Details

Name:	us-gaap_NoncashOrPartNoncashAcquisitionValueOfAssetsAcquired1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The cash outflow associated with the acquisition of business during the period. The cash portion only of the acquisition price.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Investing Activities

-URI http://asc.fasb.org/extlink&oid=6516133

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 13

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3213-108585

+ Details

Name:	us-gaap_PaymentsToAcquireBusinessesGross
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The cash inflow during the period from additional borrowings in aggregate debt. Includes proceeds from short-term and long-term debt.

+ References

No definition available.

+ Details

Name:	us-gaap_ProceedsFromIssuanceOfDebt
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

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Subsequent Events - Additional Information (Details) (USD $)	0 Months Ended
	Apr. 27, 2015	Apr. 24, 2015	Mar. 31, 2015
Subsequent Event [Line Items]
Common Stock, shares issued			1us-gaap_CommonStockSharesIssued
Common Stock, par value			$ 0.01
Subsequent Event \| Interest Rate Swap
Subsequent Event [Line Items]
Derivative, notional amount	$ 2,140,000,000
Derivative, maturity date	Oct. 24, 2022
Derivative, weighted average fixed rate	2.105%
LIBOR, minimum variable rate	1.00%
Subsequent Event \| Minimum
Subsequent Event [Line Items]
Aggregate borrowing amount		150,000,000
Subsequent Event \| Maximum
Subsequent Event [Line Items]
Consolidated total leverage ratio		6.50%
Consolidated secured leverage ratio		5.00%
Subsequent Event \| Maximum \| Pro Forma
Subsequent Event [Line Items]
Consolidated secured leverage ratio		4.00%
Subsequent Event \| Consumer CLEC Business
Subsequent Event [Line Items]
Term loan issue price as a percentage of par		98.00%
Debt amortization percentage		1.00%
Subsequent Event \| Consumer CLEC Business \| Interest Rate Swap
Subsequent Event [Line Items]
Derivative, notional amount	2,140,000,000
Derivative, maturity date	Oct. 24, 2022
Derivative, weighted average fixed rate	2.105%
LIBOR, minimum variable rate	1.00%
Subsequent Event \| Consumer CLEC Business \| Eurodollar
Subsequent Event [Line Items]
Debt instrument, floor rate		1.00%
Debt instrument, basis spread on variable rate		4.00%
Subsequent Event \| Consumer CLEC Business \| Senior Secured Term Loan B Facility
Subsequent Event [Line Items]
Issuance of senior notes, principal amount		2,140,000,000
Debt instrument, maturity period		2022-10
Subsequent Event \| Consumer CLEC Business \| Senior Secured Revolving Credit Facility
Subsequent Event [Line Items]
Issuance of senior notes, principal amount		500,000,000
Debt instrument, maturity period		2020-04
Subsequent Event \| Consumer CLEC Business \| Minimum
Subsequent Event [Line Items]
Aggregate borrowing amount		150,000,000
Subsequent Event \| Consumer CLEC Business \| Minimum \| London Interbank Offered Rate (LIBOR)
Subsequent Event [Line Items]
Debt instrument, basis spread on variable rate		1.75%
Subsequent Event \| Consumer CLEC Business \| Maximum
Subsequent Event [Line Items]
Consolidated total leverage ratio		6.50%
Consolidated secured leverage ratio		5.00%
Subsequent Event \| Consumer CLEC Business \| Maximum \| Pro Forma
Subsequent Event [Line Items]
Consolidated secured leverage ratio		4.00%
Subsequent Event \| Consumer CLEC Business \| Maximum \| London Interbank Offered Rate (LIBOR)
Subsequent Event [Line Items]
Debt instrument, basis spread on variable rate		2.25%
Subsequent Event \| Windstream \| Stock Distribution \| Consumer CLEC Business
Subsequent Event [Line Items]
Percentage of stock distributed		80.40%
Subsequent Event \| C S L Capital Llc
Subsequent Event [Line Items]
Term loan issue price as a percentage of par		98.00%
Debt amortization percentage		1.00%
Subsequent Event \| C S L Capital Llc \| Eurodollar
Subsequent Event [Line Items]
Debt instrument, floor rate		1.00%
Debt instrument, basis spread on variable rate		4.00%
Subsequent Event \| C S L Capital Llc \| Senior Secured Term Loan B Facility
Subsequent Event [Line Items]
Issuance of senior notes, principal amount		2,140,000,000
Debt instrument, maturity period		2022-10
Subsequent Event \| C S L Capital Llc \| Senior Secured Revolving Credit Facility
Subsequent Event [Line Items]
Issuance of senior notes, principal amount		500,000,000
Debt instrument, maturity period		2020-04
Subsequent Event \| C S L Capital Llc \| Minimum \| London Interbank Offered Rate (LIBOR)
Subsequent Event [Line Items]
Debt instrument, basis spread on variable rate		1.75%
Subsequent Event \| C S L Capital Llc \| Maximum \| London Interbank Offered Rate (LIBOR)
Subsequent Event [Line Items]
Debt instrument, basis spread on variable rate		2.25%
Subsequent Event \| C S L Capital Llc \| 6.00% Senior Secured Notes
Subsequent Event [Line Items]
Issuance of senior notes, principal amount		400,000,000
Issuance senior notes, stated percentage		6.00%
Notes issue price percentage		100.00%
Subsequent Event \| C S L Capital Llc \| Senior Secured Notes
Subsequent Event [Line Items]
Debt instrument, maturity date		Apr. 15, 2023
Subsequent Event \| C S L Capital Llc \| Senior Unsecured Notes
Subsequent Event [Line Items]
Debt instrument, maturity date		Oct. 15, 2023
Subsequent Event \| C S L Capital Llc \| 8.25% Senior Unsecured Notes
Subsequent Event [Line Items]
Issuance of senior notes, principal amount		1,110,000,000
Issuance senior notes, stated percentage		8.25%
Notes issue price percentage		97.055%
Subsequent Event \| C S L Capital Llc \| Senior Notes
Subsequent Event [Line Items]
Proceeds from issuance of debt		0
Subsequent Event \| C S L Capital Llc \| Consumer CLEC Business \| 6.00% Senior Secured Notes
Subsequent Event [Line Items]
Issuance of senior notes, principal amount		400,000,000
Issuance senior notes, stated percentage		6.00%
Notes issue price percentage		100.00%
Subsequent Event \| C S L Capital Llc \| Consumer CLEC Business \| Senior Secured Notes
Subsequent Event [Line Items]
Debt instrument, maturity date		Apr. 15, 2023
Subsequent Event \| C S L Capital Llc \| Consumer CLEC Business \| Senior Unsecured Notes
Subsequent Event [Line Items]
Debt instrument, maturity date		Oct. 15, 2023
Subsequent Event \| C S L Capital Llc \| Consumer CLEC Business \| 8.25% Senior Unsecured Notes
Subsequent Event [Line Items]
Issuance of senior notes, principal amount		1,110,000,000
Issuance senior notes, stated percentage		8.25%
Notes issue price percentage		97.055%
Subsequent Event \| C S L Capital Llc \| Consumer CLEC Business \| Senior Notes
Subsequent Event [Line Items]
Proceeds from issuance of debt		0
Subsequent Event \| Windstream Services Llc
Subsequent Event [Line Items]
Proceeds from issuance of debt		62,200,000
Issuers transferred cash proceeds to parent		1,040,000,000
Subsequent Event \| Windstream Services Llc \| Consumer CLEC Business
Subsequent Event [Line Items]
Proceeds from issuance of debt		62,200,000
Issuers transferred cash proceeds to parent		1,040,000,000
Subsequent Event \| Spinoff \| Windstream
Subsequent Event [Line Items]
Common Stock, shares issued		149,800,000
Common Stock, par value		0.0001
Common stock, ownership interest percentage		19.60%
Subsequent Event \| Spinoff \| Windstream \| Consumer CLEC Business
Subsequent Event [Line Items]
Common Stock, shares issued		149,800,000
Common Stock, par value		0.0001
Common stock, ownership interest percentage		19.60%
Amount of assets transferred		2,500,000,000
Subsequent Event \| Spinoff \| Windstream \| Stock Distribution
Subsequent Event [Line Items]
Percentage of stock distributed		80.40%
Subsequent Event \| Spinoff \| Windstream \| Stock Distribution \| Consumer CLEC Business
Subsequent Event [Line Items]
Percentage of stock distributed		80.40%