Schedule of Identifiable Intangible Assets Acquired, by Major Asset Class (Detail) (Antenna, USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014
Acquired Finite-Lived Intangible Assets [Line Items]
Value of acquired intangible assets	$ 10,355
Weighted-average amortization period	3 years 2 months 12 days
Customer-related intangible assets
Acquired Finite-Lived Intangible Assets [Line Items]
Value of acquired intangible assets	4,279
Weighted-average amortization period	4 years
Technology
Acquired Finite-Lived Intangible Assets [Line Items]
Value of acquired intangible assets	3,656
Weighted-average amortization period	3 years
Non-compete
Acquired Finite-Lived Intangible Assets [Line Items]
Value of acquired intangible assets	1,342
Weighted-average amortization period	1 year
Trade name
Acquired Finite-Lived Intangible Assets [Line Items]
Value of acquired intangible assets	$ 1,078
Weighted-average amortization period	3 years