AFFILIATE AND RELATED PARTY TRANSACTIONS - Amounts Due From and Due to Related Parties (Details) - Affiliates - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Related Party Transaction [Line Items]
Due from related parties and affiliates	$ 21,146	$ 19,764
Due to related parties and affiliates	11,078	10,998
Altice US Finance S.A.
Related Party Transaction [Line Items]
Due from related parties and affiliates	12,951	12,951
Newsday
Related Party Transaction [Line Items]
Due from related parties and affiliates	2,558	2,713
Due to related parties and affiliates	33	33
Altice Management Americas
Related Party Transaction [Line Items]
Due from related parties and affiliates	1,271	33
I24
Related Party Transaction [Line Items]
Due from related parties and affiliates	4,335	4,036
Altice Labs S.A.
Related Party Transaction [Line Items]
Due to related parties and affiliates	1,051	7,354
Other Altice N.V. subsidiaries
Related Party Transaction [Line Items]
Due from related parties and affiliates	31	31
Due to related parties and affiliates	2,494	3,611
Altice Management International
Related Party Transaction [Line Items]
Due to related parties and affiliates	$ 7,500	$ 0