NATURE OF OPERATIONS AND BASIS OF PRESENTATION - Narrative (Details) ft² in Millions	9 Months Ended
	Sep. 30, 2018 ft² datacenter market point_of_presence
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of datacenters (datacenter) | datacenter	53
Number of metropolitan markets (market) | market	21
Number of POPs (point of presence) | point_of_presence	102
Area under lease (sqft)	1.0
Area of data centers (sqft)	0.6