Debt Instrument, Increase in Line of Credit Facility

No definition available.

Name:	atus_DebtInstrumentIncreaseinLineofCreditFacility
Namespace Prefix:	atus_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Line of Credit, Covenant Compliance, Cash Proceeds Requirement of Certain Assets Sales, Reinvestment Rights and Other

+ References

No definition available.

+ Details

Name:	atus_LineofCreditCovenantComplianceCashProceedsRequirementofCertainAssetsSalesReinvestmentRightsandOther
Namespace Prefix:	atus_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Line of Credit, Covenant Compliance, Excess Cash Flow, Percentage Required When Minimum Leverage Ratio is Fulfilled

+ References

No definition available.

+ Details

Name:	atus_LineofCreditCovenantComplianceExcessCashFlowPercentageRequiredWhenMinimumLeverageRatioisFulfilled
Namespace Prefix:	atus_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Line of Credit, Covenant Compliance, Excess Cash Flow, Percentage Required When Minimum Leverage Ratio is Not Met

+ References

No definition available.

+ Details

Name:	atus_LineofCreditCovenantComplianceExcessCashFlowPercentageRequiredWhenMinimumLeverageRatioisNotMet
Namespace Prefix:	atus_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Line of Credit Facility, Covenant, Maximum Leverage Maintenance required as a Percentage of EBITDA

+ References

No definition available.

+ Details

Name:	atus_LineofCreditFacilityCovenantMaximumLeverageMaintenanceRequiredasaPercentageofEBITDA
Namespace Prefix:	atus_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	duration

- Definition

Line of Credit Facility, Periodic Payment, Percentage of Principal

+ References

No definition available.

+ Details

Name:	atus_LineofCreditFacilityPeriodicPaymentPercentageofPrincipal
Namespace Prefix:	atus_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Minimum Debt Leverage Ratio Required for Zero Percent of Excess Cash Flow Obligation to Prepay Debt

+ References

No definition available.

+ Details

Name:	atus_MinimumDebtLeverageRatioRequiredforZeroPercentofExcessCashFlowObligationtoPrepayDebt
Namespace Prefix:	atus_
Data Type:	xbrli:pureItemType
Balance Type:	na
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

Difference between the fair value of payments made and the carrying amount of debt which is extinguished prior to maturity.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 50
-Section 40
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=49170532&loc=d3e12317-112629

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3602-108585

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 50
-Section 40
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=49170532&loc=d3e12355-112629

+ Details

Name:	us-gaap_GainsLossesOnExtinguishmentOfDebt
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
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

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-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

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_LineOfCreditFacilityLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
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

Amount of the required periodic payment applied to principal.

+ References

+ Details

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

- Definition

The cash outflow for a long-term debt where the holder has highest claim on the entity's asset in case of bankruptcy or liquidation during the period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 15
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3291-108585

+ Details

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

- Details

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

- Details

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

- Details

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

- Details

Name:	us-gaap_VariableRateAxis=us-gaap_BaseRateMember
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:	us-gaap_DebtInstrumentAxis=atus_CequelRevolvingCreditFacilityMember
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=atus_CequelandCequelCapital6.375SeniorNotesdueSeptember152020Member
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- Details

Name:	us-gaap_DebtInstrumentAxis=atus_CequelCreditFacilitiesMember
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DEBT - Cequel Credit Facilities (Details) - USD ($)		12 Months Ended
DEBT - Cequel Credit Facilities (Details) - USD ($)	Mar. 15, 2017	Dec. 31, 2017	Dec. 31, 2016
Line of Credit Facility [Line Items]
Principal Amount		$ 4,693,675,000
Credit facility		4,643,523,000	$ 3,444,790,000
Redemption of debt amount		1,729,400,000	0
Loss on extinguishment of debt and write-off of deferred financing costs	$ 18,976,000	600,240,000	127,649,000
Senior Notes
Line of Credit Facility [Line Items]
Principal Amount		16,289,245,000
Cequel Term Loan Facility \| Term Loan
Line of Credit Facility [Line Items]
Line of credit facility, aggregate principal amount	1,265,000,000	1,265,000,000
Principal Amount		1,258,675,000
Line of credit facility, increase in borrowing capacity	450,000,000
Credit facility	812,963,000	$ 1,250,217,000	812,903,000
Loss on extinguishment of debt and write-off of deferred financing costs	28,684,000
Line of credit facility periodic payment, percentage of principal		0.25%
Line of credit facility, periodic payment amount		$ 3,163,000
Cequel Term Loan Facility \| Term Loan \| Alternate Base Rate
Line of Credit Facility [Line Items]
Basis spread on variable rate		1.25%
Cequel Term Loan Facility \| Term Loan \| Eurodollar
Line of Credit Facility [Line Items]
Basis spread on variable rate		2.25%
Cequel Revolving Credit Facility \| Revolving Credit Facility
Line of Credit Facility [Line Items]
Line of credit facility, aggregate principal amount		$ 350,000,000
Principal Amount		0
Credit facility		$ 0	$ 0
Cequel Revolving Credit Facility \| Revolving Credit Facility \| Alternate Base Rate
Line of Credit Facility [Line Items]
Basis spread on variable rate		2.25%
Cequel Revolving Credit Facility \| Revolving Credit Facility \| Eurodollar
Line of Credit Facility [Line Items]
Basis spread on variable rate		3.25%
6.375% Senior Notes due September 15, 2020 \| Senior Notes
Line of Credit Facility [Line Items]
Principal Amount		$ 1,050,000,000
Redemption of debt amount	$ 450,000,000
Stated interest rate	6.375%	6.375%
Cequel Credit Facilities
Line of Credit Facility [Line Items]
Percentage of proceeds from asset sales required to pay down term loans		100.00%
Percentage of excess cash flow required when minimum leverage ratio is not met		50.00%
Percentage of excess cash flow required to pay down term loans when minimum leverage ratio is fulfilled		0.00%
Minimum debt leverage ratio required for zero percent of excess cash flow obligation to prepay debt		4.5
Leverage maintenance covenant		5.0