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 issued percent of par.

+ References

No definition available.

+ Details

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

- Definition

Debt instruments maturity period.

+ References

No definition available.

+ Details

Name:	csal_DebtInstrumentsMaturityPeriod
Namespace Prefix:	csal_
Data Type:	xbrli:gYearMonthItemType
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

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

- Definition

Amount of amortization expense attributable to debt issuance costs.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=64930785&loc=d3e28555-108399

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-URI http://asc.fasb.org/extlink&oid=66902209&loc=d3e3602-108585

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03(8))
-URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 225
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04(8))
-URI http://asc.fasb.org/extlink&oid=6879574&loc=d3e536633-122882

+ Details

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

- 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 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=64930739&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=64930785&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

+ 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

- Definition

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

+ References

+ Details

Name:	us-gaap_DebtInstrumentMaturityDate
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 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: 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

Reference 3: 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

+ Details

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

- Definition

Date the credit facility terminates, in CCYY-MM-DD format.

+ References

+ Details

Name:	us-gaap_LineOfCreditFacilityExpirationDate1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- 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

+ Details

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

- 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=66902209&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

Name:	us-gaap_RangeAxis=us-gaap_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RangeAxis=us-gaap_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementScenarioAxis=us-gaap_ProFormaMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_BusinessAcquisitionAxis=csal_TowerCloudIncMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CreditFacilityAxis=us-gaap_RevolvingCreditFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

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

- Details

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

- Details

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

- Details

Name:	dei_LegalEntityAxis=csal_CSLCapitalLLCMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

Name:	us-gaap_VariableRateAxis=us-gaap_LondonInterbankOfferedRateLIBORMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

Name:	us-gaap_VariableRateAxis=us-gaap_EurodollarMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=csal_WindstreamServicesLLCMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Notes and Other Debt - Additional Information (Details) - USD ($)				3 Months Ended	5 Months Ended	8 Months Ended	9 Months Ended
	Aug. 31, 2016	Jun. 09, 2016	Apr. 25, 2015	Jun. 30, 2016	Sep. 30, 2015	Dec. 31, 2015	Sep. 30, 2016	Aug. 26, 2016	Apr. 22, 2016	Apr. 24, 2015
Debt Instrument [Line Items]
Amortization of deferred financing costs				$ 2,000,000	$ 3,039,000		$ 5,640,000
Minimum
Debt Instrument [Line Items]
Aggregate borrowing amount										$ 150,000,000
Maximum
Debt Instrument [Line Items]
Consolidated secured leverage ratio										500.00%
Consolidated total leverage ratio										650.00%
Maximum \| Pro Forma
Debt Instrument [Line Items]
Consolidated secured leverage ratio										400.00%
Tower Cloud
Debt Instrument [Line Items]
Issuers transferred cash proceeds to parent	$ 187,700,000
Tower Cloud \| Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Aggregate borrowing amount								$ 150,000,000
Senior Secured Revolving Credit Facility
Debt Instrument [Line Items]
Line of credit facility, expiration date							Apr. 24, 2020
Senior Secured Notes - 6.00% Due April 15, 2023
Debt Instrument [Line Items]
Issuance senior notes, stated percentage						6.00%	6.00%
Debt instrument, maturity date						Apr. 15, 2023	Apr. 15, 2023
Senior Unsecured Notes - 8.25% Due October 15, 2023
Debt Instrument [Line Items]
Issuance senior notes, stated percentage						8.25%	8.25%
Debt instrument, maturity date						Oct. 15, 2023	Oct. 15, 2023
Senior Secured Term Loan B Facility
Debt Instrument [Line Items]
Debt instrument, maturity date						Oct. 24, 2022	Oct. 24, 2022
CSL Capital, LLC
Debt Instrument [Line Items]
Term loan issue price as a percentage of par										98.00%
CSL Capital, LLC \| Senior Notes
Debt Instrument [Line Items]
Proceeds from issuance of debt			$ 0
CSL Capital, LLC \| Senior Secured Revolving Credit Facility
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity									$ 321,000,000
Aggregate borrowing amount									$ 500,000,000
Line of credit facility, expiration date							Apr. 24, 2020
CSL Capital, LLC \| Senior Secured Revolving Credit Facility \| Minimum \| London Interbank Offered Rate (LIBOR)
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate			1.75%
CSL Capital, LLC \| Senior Secured Revolving Credit Facility \| Maximum \| London Interbank Offered Rate (LIBOR)
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate			2.25%
CSL Capital, LLC \| Senior Secured Notes - 6.00% Due April 15, 2023
Debt Instrument [Line Items]
Issuance of senior notes, principal amount		$ 150,000,000
Issuance senior notes, stated percentage		6.00%
Debt instrument, maturity date							Apr. 15, 2023
Notes issued price percentage at par		99.25%
CSL Capital, LLC \| Senior Secured Notes - 8.25% Due October 15, 2023
Debt Instrument [Line Items]
Issuance of senior notes, principal amount										$ 400,000,000
Notes issued price percentage at par			100.00%
CSL Capital, LLC \| Senior Unsecured Notes - 8.25% Due October 15, 2023
Debt Instrument [Line Items]
Issuance of senior notes, principal amount										$ 1,110,000,000
Issuance senior notes, stated percentage										8.25%
Debt instrument, maturity date							Oct. 15, 2023
Notes issued price percentage at par			97.055%
CSL Capital, LLC \| Senior Secured Term Loan B Facility
Debt Instrument [Line Items]
Issuance of senior notes, principal amount										$ 2,140,000,000
Debt instrument, maturity period							2022-10
Debt amortization percentage										1.00%
CSL Capital, LLC \| Senior Secured Term Loan B Facility \| Eurodollar
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate			4.00%
CSL Capital, LLC \| Senior Secured Term Loan B Facility \| Minimum \| Eurodollar
Debt Instrument [Line Items]
Issuance senior notes, stated percentage										1.00%
Windstream Services LLC
Debt Instrument [Line Items]
Issuers transferred cash proceeds to parent			$ 1,040,000,000