OPERATING SEGMENTS - Summary of operating results for business segments (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Revenues:
Total revenues	$ 69,642	$ 74,315	$ 141,775	$ 150,239
Direct costs of sales and services, customer support and sales and marketing, exclusive of depreciation and amortization:
Total direct costs of sales and services, customer support and sales and marketing	39,557	46,366	82,351	93,670
Business unit contribution:
Total business unit contribution	30,085	27,949	59,424	56,569
Exit activities, restructuring and impairments	4,628	152	5,651	353
Other operating expenses, including depreciation and amortization	27,510	30,271	55,334	60,891
Loss from operations	(2,053)	(2,474)	(1,561)	(4,675)
Non-operating expenses	17,336	8,198	25,570	15,538
Loss before income taxes and equity in earnings of equity-method investment	(19,389)	(10,672)	(27,131)	(20,213)
INAP COLO
Revenues:
Total revenues	52,044	55,827	105,383	111,708
Direct costs of sales and services, customer support and sales and marketing, exclusive of depreciation and amortization:
Total direct costs of sales and services, customer support and sales and marketing	30,060	35,837	63,476	72,326
Business unit contribution:
Total business unit contribution	21,984	19,990	41,907	39,382
INAP CLOUD
Revenues:
Total revenues	17,598	18,488	36,392	38,531
Direct costs of sales and services, customer support and sales and marketing, exclusive of depreciation and amortization:
Total direct costs of sales and services, customer support and sales and marketing	9,497	10,529	18,875	21,344
Business unit contribution:
Total business unit contribution	$ 8,101	$ 7,959	$ 17,517	$ 17,187