Summary of Significant Accounting Policies - Depreciation of Property and Equipment Estimated Useful Lives (Detail)	12 Months Ended
	Dec. 31, 2015
Office Equipment, Furniture, Fixtures and Other [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Depreciation of property and equipment estimated useful lives	3 years
Office Equipment, Furniture, Fixtures and Other [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Depreciation of property and equipment estimated useful lives	7 years
Leasehold Improvements [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Depreciation of property and equipment estimated useful lives	3 years
Leasehold Improvements [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Depreciation of property and equipment estimated useful lives	13 years
Airborne Equipment [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Depreciation of property and equipment estimated useful lives	7 years
Network Equipment [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Depreciation of property and equipment estimated useful lives	5 years
Network Equipment [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Depreciation of property and equipment estimated useful lives	25 years