EXIT ACTIVITIES AND RESTRUCTURING LIABILITIES - Summary of activity and balances for restructuring and asset impairment activity (Details) - Data center and network services - Exit activities and Restructuring charges - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Restructuring Reserve [Roll Forward]
December 31, 2015 and 2014	$ 3,878	$ 4,510
Initial Charges	147
Plan Adjustments	199	$ 371
Cash Payments	(803)	(663)
March 31, 2016 and 2015	$ 3,421	4,218
2016 exit activities
Restructuring Reserve [Roll Forward]
December 31, 2015 and 2014
Initial Charges	$ 147
Plan Adjustments
Cash Payments	$ (9)
March 31, 2016 and 2015	138
2015 exit activities
Restructuring Reserve [Roll Forward]
December 31, 2015 and 2014	$ 1,007
Initial Charges
Plan Adjustments
Cash Payments	$ (172)
March 31, 2016 and 2015	835
2014 exit activities
Restructuring Reserve [Roll Forward]
December 31, 2015 and 2014	$ 1,701	$ 2,010
Initial Charges
Plan Adjustments	$ 18	$ 206
Cash Payments	(144)	(121)
March 31, 2016 and 2015	1,575	2,095
2007 restructuring
Restructuring Reserve [Roll Forward]
December 31, 2015 and 2014	$ 1,170	$ 2,325
Initial Charges
Plan Adjustments	$ 181	$ 160
Cash Payments	(478)	(454)
March 31, 2016 and 2015	$ 873	2,031
Other
Restructuring Reserve [Roll Forward]
December 31, 2015 and 2014		$ 175
Initial Charges
Plan Adjustments		$ 5
Cash Payments		(88)
March 31, 2016 and 2015		$ 92