REVENUES - Summary of Revenue by Geography (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net revenues	$ 82,972	$ 68,907	$ 239,135	$ 210,682
INAP US
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net revenues	66,825	54,006	190,071	165,757
INAP INTL
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net revenues	16,147	14,901	49,064	44,925
United States | INAP US
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net revenues	66,825	54,006	190,071	165,757
United States | INAP INTL
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net revenues	0	0	0	0
Canada | INAP US
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net revenues	0	0	0	0
Canada | INAP INTL
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net revenues	9,187	9,421	27,846	29,320
Other countries | INAP US
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net revenues	0	0	0	0
Other countries | INAP INTL
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net revenues	$ 6,960	$ 5,480	$ 21,218	$ 15,605