REVENUES - Schedule of Adjustments to Previously Reported Financial Statements from the Adoption (Details) - USD ($) $ / shares in Units, $ in Thousands	Mar. 31, 2018	Jan. 01, 2018	Dec. 31, 2017	Mar. 31, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 16,159	$ 14,603	$ 14,603	$ 9,174	$ 10,389
Accounts receivable, net of allowance for doubtful accounts of $1,700 and $1,487, respectively	17,524	17,794	17,794
Prepaid expenses and other assets	8,690	15,487	8,673
Total current assets	49,504	47,884	41,070
Property and equipment, net	461,314	458,565	458,565
Intangible assets, net	79,185	25,666	25,666
Goodwill	118,077	50,209	50,209
Deposits and other assets	11,784	23,229	11,015
Total assets	731,920	605,553	586,525
Current liabilities:
Accounts payable	21,699	20,388	20,388
Accrued liabilities	14,279	15,908	15,908
Deferred revenues	5,871	4,112	4,861
Capital lease obligations	10,095	11,711	11,711
Revolving credit facility	16,000	5,000	5,000
Term loan, less discount and prepaid costs of $3,539 and $2,133, respectively	818	867	867
Exit activities and restructuring liability	3,391	4,152	4,152
Other current liabilities	4,197	1,707	1,707
Total current liabilities	76,350	63,845	64,594
Capital lease obligations	223,549	223,749	223,749
Term loan, less discount and prepaid costs of $11,286 and $7,655, respectively	416,766	287,845	287,845
Exit activities and restructuring liability	408	664	664
Deferred rent	1,138	1,310	1,310
Deferred tax liability	1,841	1,860	1,651
Other long-term liabilities	3,046	3,128	7,744
Total liabilities	723,098	582,401	587,557
Commitments and contingencies
Stockholders’ deficit:
Preferred stock, $0.001 par value; 5,000 shares authorized; no shares issued or outstanding	0	0	0
Common stock, $0.001 par value; 30,000 shares authorized; 21,131 and 20,804 shares outstanding, respectively	21	21	21
Additional paid-in capital	1,327,985	1,327,084	1,327,084
Treasury stock, at cost, 313 and 293 shares, respectively	(7,429)	(7,159)	(7,159)
Accumulated deficit	(1,313,598)	(1,299,539)	(1,323,723)
Accumulated items of other comprehensive loss	(1,263)	(1,324)	(1,324)
Total INAP stockholders’ deficit	5,716	19,083	(5,101)
Non-controlling interests	3,106	4,069	4,069
Total stockholders’ deficit	8,822	23,152	(1,032)
Total liabilities and stockholders’ deficit	731,920	605,553	586,525
Allowance for doubtful accounts receivable	1,700		1,487
Term loan current, discount and prepaid costs	3,539		2,133
Term loan deferred, discount and prepaid costs	$ 11,286		$ 7,655
Preferred stock, par value (in dollars per share)	$ 0.001		$ 0.001
Preferred stock, shares authorized (in shares)	5,000,000		5,000,000
Preferred stock, shares issued (in shares)	0		0
Preferred stock, shares outstanding (in shares)	0		0
Common stock, par value (in dollars per share)	$ 0.001		$ 0.001
Common stock, shares authorized (in shares)	30,000,000		30,000,000
Common stock, shares outstanding (in shares)	21,131,000		20,804,000
Treasury stock, shares (in shares)	313,000		293,000
Balances without Adoption of ASC 606
Current assets:
Cash and cash equivalents	$ 16,159		$ 14,603
Accounts receivable, net of allowance for doubtful accounts of $1,700 and $1,487, respectively	17,524		17,794
Prepaid expenses and other assets	8,690		8,673
Total current assets	49,245		41,070
Property and equipment, net	461,314		458,565
Intangible assets, net	79,185		25,666
Goodwill	118,077		50,209
Deposits and other assets	11,784		11,015
Total assets	731,632		586,525
Current liabilities:
Accounts payable	21,699		20,388
Accrued liabilities	14,279		15,908
Deferred revenues	6,062		4,861
Capital lease obligations	10,095		11,711
Revolving credit facility	16,000		5,000
Term loan, less discount and prepaid costs of $3,539 and $2,133, respectively	818		867
Exit activities and restructuring liability	3,391		4,152
Other current liabilities	4,197		1,707
Total current liabilities	76,541		64,594
Capital lease obligations	223,549		223,749
Term loan, less discount and prepaid costs of $11,286 and $7,655, respectively	416,766		287,845
Exit activities and restructuring liability	408		664
Deferred rent	1,138		1,310
Deferred tax liability	1,841		1,651
Other long-term liabilities	2,902		7,744
Total liabilities	723,145		587,557
Commitments and contingencies
Stockholders’ deficit:
Preferred stock, $0.001 par value; 5,000 shares authorized; no shares issued or outstanding	0		0
Common stock, $0.001 par value; 30,000 shares authorized; 21,131 and 20,804 shares outstanding, respectively	21		21
Additional paid-in capital	1,327,985		1,327,084
Treasury stock, at cost, 313 and 293 shares, respectively	(7,429)		(7,159)
Accumulated deficit	(1,313,933)		(1,323,723)
Accumulated items of other comprehensive loss	(1,263)		(1,324)
Total INAP stockholders’ deficit	5,381		(5,101)
Non-controlling interests	3,106		4,069
Total stockholders’ deficit	8,487		(1,032)
Total liabilities and stockholders’ deficit	731,632		$ 586,525
Effect of Change Higher/ (Lower) | Accounting Standards Update 2014-09
Current assets:
Cash and cash equivalents	0	0
Accounts receivable, net of allowance for doubtful accounts of $1,700 and $1,487, respectively	0	0
Prepaid expenses and other assets	0	6,814
Total current assets	259	6,814
Property and equipment, net	0	0
Intangible assets, net	0	0
Goodwill	0	0
Deposits and other assets	0	12,214
Total assets	288	19,028
Current liabilities:
Accounts payable	0	0
Accrued liabilities	0	0
Deferred revenues	(191)	(749)
Capital lease obligations	0	0
Revolving credit facility	0	0
Term loan, less discount and prepaid costs of $3,539 and $2,133, respectively	0	0
Exit activities and restructuring liability	0	0
Other current liabilities	0	0
Total current liabilities	(191)	(749)
Capital lease obligations	0	0
Term loan, less discount and prepaid costs of $11,286 and $7,655, respectively	0	0
Exit activities and restructuring liability	0	0
Deferred rent	0	0
Deferred tax liability	0	209
Other long-term liabilities	144	(4,616)
Total liabilities	(47)	(5,156)
Commitments and contingencies
Stockholders’ deficit:
Preferred stock, $0.001 par value; 5,000 shares authorized; no shares issued or outstanding	0	0
Common stock, $0.001 par value; 30,000 shares authorized; 21,131 and 20,804 shares outstanding, respectively	0	0
Additional paid-in capital	0	0
Treasury stock, at cost, 313 and 293 shares, respectively	0	0
Accumulated deficit	335	24,184
Accumulated items of other comprehensive loss	0	0
Total INAP stockholders’ deficit	335	24,184
Non-controlling interests	0	0
Total stockholders’ deficit	335	24,184
Total liabilities and stockholders’ deficit	$ 288	$ 19,028