NATURE OF OPERATIONS AND BASIS OF PRESENTATION - Narrative (Details) ft² in Thousands	6 Months Ended
	Jun. 30, 2017 ft² datacenter market point_of_presence
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of metropolitan markets (market) | market	20
Number of datacenters (datacenter) | datacenter	46
Number of POPs (point of presence) | point_of_presence	85
Area under lease (sqft)	950
Area of data centers (sqft)	500
Area of raised floor (sqft)	325
Area occupied (sqft)	200