OPERATING SEGMENTS - Summary of operating results for business segments (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Revenues:
Total revenues	$ 68,907	$ 73,940	$ 210,682	$ 224,180
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	38,142	46,222	120,493	139,892
Business unit contribution:
Total business unit contribution	30,765	27,718	90,189	84,288
Exit activities, restructuring and impairments	745	1,670	6,396	2,023
Other operating expenses, including depreciation and amortization	29,288	109,446	84,622	170,338
Income (loss) from operations	732	(83,398)	(829)	(88,073)
Non-operating expenses	12,496	7,848	38,066	23,387
Loss before income taxes and equity in earnings of equity-method investment	(11,764)	(91,246)	(38,895)	(111,460)
INAP COLO
Revenues:
Total revenues	51,344	54,998	156,727	166,707
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	29,048	35,893	92,524	108,219
Business unit contribution:
Total business unit contribution	22,296	19,105	64,203	58,488
INAP CLOUD
Revenues:
Total revenues	17,563	18,942	53,955	57,473
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	9,094	10,329	27,969	31,673
Business unit contribution:
Total business unit contribution	$ 8,469	$ 8,613	$ 25,986	$ 25,800