LEASES - Future Minimum Lease Payments (Details) $ in Thousands	Jun. 30, 2020 USD ($)
Finance Lease, Liability, Payments, Due Next Twelve Months	$ 30,527
Finance Lease, Liability, Payments, Due Year Two	50,543
Finance Lease, Liability, Payments, Due Year Three	46,298
Finance Lease, Liability, Payments, Due Year Four	15,501
Finance Lease, Liability, Payments, Due Year Five	3,413
Finance Lease, Liability, Payments, Due after Year Five	300
Finance Lease, Liability, Payment, Due, Total	146,582
Finance Leases, Future Minimum Payments, Interest Included in Payments	10,533
Finance Leases, Future Minimum Payments, Present Value of Net Minimum Payments	136,049
Lessee, Operating Lease, Liability, Payments, Due Next Twelve Months	27,389
Lessee, Operating Lease, Liability, Payments, Due Year Two	43,615
Lessee, Operating Lease, Liability, Payments, Due Year Three	49,668
Lessee, Operating Lease, Liability, Payments, Due Year Four	39,694
Lessee, Operating Lease, Liability, Payments, Due Year Five	35,261
Lessee, Operating Lease, Liability, Payments, Due after Year Five	200,665
Lessee, Operating Lease, Liability, Payments, Due, Total	396,292
Operating Leases, Future Minimum Payments, Interest Included in Payments	96,555
Operating Leases, Future Minimum Payments, Present Value of Net Minimum Payments	$ 299,737

Finance Leases, Future Minimum Payments, Interest Included in Payments

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- Definition

Finance Leases, Future Minimum Payments, Present Value of Net Minimum Payments

+ References

No definition available.

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- Definition

Operating Leases, Future Minimum Payments, Interest Included in Payments

+ References

No definition available.

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- Definition

Operating Leases, Future Minimum Payments, Present Value of Net Minimum Payments

+ References

No definition available.

+ Details

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Namespace Prefix:	atus_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
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- Definition

Amount of lessee's undiscounted obligation for lease payments for finance lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 50
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=121609121&loc=SL77918701-209980

+ Details

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- Definition

Amount of lessee's undiscounted obligation for lease payment for finance lease to be paid after fifth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

+ Details

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- Definition

Amount of lessee's undiscounted obligation for lease payment for finance lease to be paid in next fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

+ Details

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- Definition

Amount of lessee's undiscounted obligation for lease payment for finance lease to be paid in fifth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

+ Details

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- Definition

Amount of lessee's undiscounted obligation for lease payment for finance lease to be paid in fourth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

+ Details

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- Definition

Amount of lessee's undiscounted obligation for lease payment for finance lease to be paid in third fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

+ Details

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- Definition

Amount of lessee's undiscounted obligation for lease payment for finance lease to be paid in second fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

+ Details

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- Definition

Amount of lessee's undiscounted obligation for lease payment for operating lease.

+ References

+ Details

Name:	us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue
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Balance Type:	credit
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- Definition

Amount of lessee's undiscounted obligation for lease payment for operating lease due after fifth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

+ Details

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- Definition

Amount of lessee's undiscounted obligation for lease payment for operating lease to be paid in next fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

+ Details

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- Definition

Amount of lessee's undiscounted obligation for lease payment for operating lease to be paid in fifth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

+ Details

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- Definition

Amount of lessee's undiscounted obligation for lease payment for operating lease to be paid in fourth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

+ Details

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- Definition

Amount of lessee's undiscounted obligation for lease payment for operating lease to be paid in third fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

+ Details

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- Definition

Amount of lessee's undiscounted obligation for lease payment for operating lease to be paid in second fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

+ Details

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