Acquisitions - Allocation of Acquired Intangible Assets and Related Estimates of Useful Lives (Detail) (Granville-Phillips [Member], USD $) In Thousands, unless otherwise specified	0 Months Ended	9 Months Ended
	May 30, 2014	Sep. 30, 2014
Acquired Finite-Lived Intangible Assets [Line Items]
Acquired intangible assets, purchase price	$ 38,850
Customer Relationships [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Acquired intangible assets, purchase price	21,250	21,250
Estimated useful life of finite lived intangible assets	7 years
Trademarks and Trade Names [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Acquired intangible assets, purchase price	1,900	1,900
Estimated useful life of finite lived intangible assets	12 years
Current Developed Technology [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Acquired intangible assets, purchase price	$ 15,700
Current Developed Technology [Member] | Minimum [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Estimated useful life of finite lived intangible assets	9 years
Current Developed Technology [Member] | Maximum [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Estimated useful life of finite lived intangible assets	12 years