Goodwill, Acquistion-Related Intangible Assets, and Other Long Lived Assets - Summary of Acquisition-Related Intangible Assets (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	$ 60,918	$ 60,094
Accumulated Amortization	(49,321)	(46,868)
Balance	11,597	13,226
Acquired customer relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	40,040	39,390
Accumulated Amortization	(31,351)	(29,564)
Balance	8,689	9,826
Acquired customer contracts [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	14,000	14,000
Accumulated Amortization	(14,000)	(14,000)
Acquired technology [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	5,117	5,117
Accumulated Amortization	(3,142)	(2,804)
Balance	1,975	2,313
Non-compete agreements [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	1,630	1,500
Accumulated Amortization	(734)	(465)
Balance	896	1,035
Acquired trademarks [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	131	87
Accumulated Amortization	(94)	(35)
Balance	$ 37	$ 52