Estimated Useful Lives of Assets in Property and Equipment (Detail)	3 Months Ended
	Mar. 31, 2012 Year
Network equipment
Property, Plant and Equipment [Line Items]
Estimated Useful Life (in years)	5
Capitalized Software
Property, Plant and Equipment [Line Items]
Estimated Useful Life (in years)	5
Leasehold improvements
Property, Plant and Equipment [Line Items]
Estimated Useful Life (in years), minimum	10
Estimated Useful Life (in years), maximum	25
Before Change In Accounting Estimate | Network equipment
Property, Plant and Equipment [Line Items]
Estimated Useful Life (in years)	3
Before Change In Accounting Estimate | Capitalized Software
Property, Plant and Equipment [Line Items]
Estimated Useful Life (in years)	3
Before Change In Accounting Estimate | Leasehold improvements
Property, Plant and Equipment [Line Items]
Estimated Useful Life (in years)	7