GOODWILL AND OTHER INTANGIBLE ASSETS - Summary of carrying amount of goodwill (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Goodwill [Roll Forward]
Goodwill	$ 172,228	$ 172,094
Accumulated impairment losses	(112,623)	(112,623)
Net	59,605	59,471
Data Center Services
Goodwill [Roll Forward]
Goodwill	20,141	20,007
Accumulated impairment losses
Net	20,141	20,007
IP Services
Goodwill [Roll Forward]
Goodwill	152,087	152,087
Accumulated impairment losses	(112,623)	(112,623)
Net	$ 39,464	$ 39,464