EXIT ACTIVITIES AND RESTRUCTURING LIABILITIES - Exit activities and restructuring charges for Real estate obligations (Details) - USD ($) $ in Thousands	9 Months Ended
Sep. 30, 2019	Sep. 30, 2018
Restructuring Reserve [Roll Forward]
Balance, beginning of period	$ 2,601	$ 4,816
Initial Charges (1)	1,629	1,821
Plan Adjustments	190	1,377
Cash Payments	(3,870)	(4,597)
Balance, end of period	550	3,417
Activity for 2019 restructuring charge: \| Real estate obligations
Restructuring Reserve [Roll Forward]
Balance, beginning of period	0
Initial Charges (1)	1,629
Plan Adjustments	(115)
Cash Payments	(1,098)
Balance, end of period	416
Activity for 2018 restructuring charge: \| Real estate obligations
Restructuring Reserve [Roll Forward]
Balance, beginning of period	1,922	0
Initial Charges (1)	0	1,821
Plan Adjustments	186	902
Cash Payments	(2,108)	(961)
Balance, end of period	0	1,762
Activity for 2017 restructuring charge: \| Real estate obligations
Restructuring Reserve [Roll Forward]
Balance, beginning of period	100	3,380
Initial Charges (1)	0	0
Plan Adjustments	(10)	220
Cash Payments	(90)	(2,747)
Balance, end of period	0	853
Activity for 2016 restructuring charge: \| Real estate obligations
Restructuring Reserve [Roll Forward]
Balance, beginning of period	125	247
Initial Charges (1)	0	0
Plan Adjustments	16	29
Cash Payments	(116)	(122)
Balance, end of period	25	154
Activity for 2016 restructuring charge: \| Severance
Restructuring Reserve [Roll Forward]
Balance, beginning of period		46
Initial Charges (1)		0
Plan Adjustments		35
Cash Payments		(35)
Balance, end of period		46
Activity for 2015 restructuring charge: \| Real estate obligations
Restructuring Reserve [Roll Forward]
Balance, beginning of period	27	64
Initial Charges (1)	0	0
Plan Adjustments	29	8
Cash Payments	(49)	(36)
Balance, end of period	7	36
Activity for 2015 restructuring charge: \| Service contracts
Restructuring Reserve [Roll Forward]
Balance, beginning of period	221	388
Initial Charges (1)	0	0
Plan Adjustments	30	22
Cash Payments	(149)	(148)
Balance, end of period	102	262
Activity for 2014 restructuring charge: \| Real estate obligations
Restructuring Reserve [Roll Forward]
Balance, beginning of period	206	691
Initial Charges (1)	0	0
Plan Adjustments	54	161
Cash Payments	(260)	(548)
Balance, end of period	$ 0	$ 304

This element represents the value of restructuring reserve after adjustments in plan.

No definition available.

Name:	inap_RestructuringReserveSubsequentPlanAdjustments
Namespace Prefix:	inap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of cash payments made as the result of exit or disposal activities. Excludes payments associated with a discontinued operation or an asset retirement obligation.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 420
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (b)(2)
-URI http://asc.fasb.org/extlink&oid=6394359&loc=d3e17939-110869

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 17
-Subparagraph (f)
-URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3367-108585

+ Details

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Period Type:	duration

- Definition

Amount of expenses associated with exit or disposal activities pursuant to an authorized plan. Excludes expenses related to a discontinued operation or an asset retirement obligation.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 420
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 5.P.3)
-URI http://asc.fasb.org/extlink&oid=115931487&loc=d3e140864-122747

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-URI http://asc.fasb.org/extlink&oid=6394359&loc=d3e17939-110869

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Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
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+ Details

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Period Type:	duration

- Definition

Carrying amount (including both current and noncurrent portions of the accrual) as of the balance sheet date pertaining to a specified type of cost associated with exit from or disposal of business activities or restructuring pursuant to a duly authorized plan.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 420
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (b)(2)
-URI http://asc.fasb.org/extlink&oid=6394359&loc=d3e17939-110869

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-URI http://asc.fasb.org/extlink&oid=115931487&loc=d3e140904-122747

+ Details

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- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

+ References

No definition available.

+ Details

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