OPERATING SEGMENTS - Narrative (Details)	6 Months Ended
	Jun. 30, 2018 point_of_presence segment
Segment Reporting [Abstract]
Number of reportable segments (segment) | segment	2
Segment Reporting Information [Line Items]
Number of POPs (point of presence)	99
Network services
Segment Reporting Information [Line Items]
Number of POPs (point of presence)	99