OPERATING SEGMENT AND GEOGRAPHIC INFORMATION - Summary of Total Assets by Segment (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	$ 586,525	$ 430,615
Operating Segments | INAP COLO
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	398,231	224,540
Operating Segments | INAP CLOUD
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	173,691	192,684
Corporate, Non-Segment
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	$ 14,603	$ 13,391