PROPERTY AND EQUIPMENT - Estimated useful lives of assets (Details 1)	12 Months Ended
	Dec. 31, 2012
Original | Network equipment
Property, Plant and Equipment [Line Items]
Estimated useful lives of assets (in years)	3 years
Original | Capitalized software
Property, Plant and Equipment [Line Items]
Estimated useful lives of assets (in years)	3 years
Original | Leasehold improvements
Property, Plant and Equipment [Line Items]
Estimated useful lives of assets (in years)	7 years
Revised | Network equipment
Property, Plant and Equipment [Line Items]
Estimated useful lives of assets (in years)	5 years
Revised | Capitalized software
Property, Plant and Equipment [Line Items]
Estimated useful lives of assets (in years)	5 years
Revised | Leasehold improvements | Minimum
Property, Plant and Equipment [Line Items]
Estimated useful lives of assets (in years)	10 years
Revised | Leasehold improvements | Maximum
Property, Plant and Equipment [Line Items]
Estimated useful lives of assets (in years)	25 years