GOODWILL AND OTHER INTANGIBLE ASSETS - Narrative (Details) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2018 USD ($)	Sep. 30, 2017 USD ($)	Sep. 30, 2018 USD ($) reporting_unit	Sep. 30, 2017 USD ($)
Goodwill and Intangible Assets Disclosure [Abstract]
Number of reportable units (reporting unit) \| reporting_unit			7
Amortization expense for intangible assets \| $	$ 3.2	$ 1.8	$ 8.0	$ 4.0

Represents amount of amortization expense expected to be recognized during the fiscal year for assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

No definition available.

Name:	inap_IntangibleAssetsAmortizationExpense
Namespace Prefix:	inap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration