Goodwill and Amortizable Intangible Assets - Net Consolidated Balance of Amortizable Intangible Assets (Detail) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2016	Dec. 31, 2015
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 41,580
Accumulated Amortization	(29,770)
Total amortizable intangible assets	$ 11,810	$ 14,964
Customer Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Useful Life (In Years)	10 years
Gross Carrying Amount	$ 25,002
Accumulated Amortization	(13,960)
Total amortizable intangible assets	11,042
Acquired Technology [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	8,454
Accumulated Amortization	(8,454)
Total amortizable intangible assets	0
Non-compete Agreements [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	2,370
Accumulated Amortization	(2,370)
Total amortizable intangible assets	$ 0
Trademarks [Member]
Finite-Lived Intangible Assets [Line Items]
Useful Life (In Years)	6 years
Gross Carrying Amount	$ 5,754
Accumulated Amortization	(4,986)
Total amortizable intangible assets	$ 768
Minimum [Member]
Finite-Lived Intangible Assets [Line Items]
Useful Life (In Years)	2 years
Minimum [Member] | Acquired Technology [Member]
Finite-Lived Intangible Assets [Line Items]
Useful Life (In Years)	2 years
Minimum [Member] | Non-compete Agreements [Member]
Finite-Lived Intangible Assets [Line Items]
Useful Life (In Years)	3 years
Maximum [Member]
Finite-Lived Intangible Assets [Line Items]
Useful Life (In Years)	10 years
Maximum [Member] | Acquired Technology [Member]
Finite-Lived Intangible Assets [Line Items]
Useful Life (In Years)	4 years
Maximum [Member] | Non-compete Agreements [Member]
Finite-Lived Intangible Assets [Line Items]
Useful Life (In Years)	5 years