Summary of Significant Accounting Policies - Property & Equipment (Details)	12 Months Ended
	Dec. 31, 2012
Network equipment | Min
Property, Plant and Equipment
Useful life of property and equipment	3 years
Network equipment | Max
Property, Plant and Equipment
Useful life of property and equipment	4 years
Buildings | Min
Property, Plant and Equipment
Useful life of property and equipment	15 years
Buildings | Max
Property, Plant and Equipment
Useful life of property and equipment	20 years
Computer software, office equipment and other | Min
Property, Plant and Equipment
Useful life of property and equipment	2 years
Computer software, office equipment and other | Max
Property, Plant and Equipment
Useful life of property and equipment	5 years