Goodwill and Intangible Assets - Goodwill (Detail) (USD $) In Thousands, unless otherwise specified	9 Months Ended	12 Months Ended
	Sep. 30, 2014	Dec. 31, 2013
Goodwill and Intangible Assets Disclosure [Abstract]
Beginning balance, Goodwill Gross Carrying Amount	$ 290,323	$ 290,147
Acquired goodwill, Gross Carrying Amount	41,993
Foreign currency translation, Gross Carrying Amount	223	176
Ending balance, Goodwill Gross Carrying Amount	332,539	290,323
Beginning balance, Accumulated Impairment (Loss)	(139,414)	(139,414)
Acquired goodwill, Accumulated Impairment (Loss)
Foreign currency translation, Accumulated Impairment (Loss)
Ending balance, Accumulated Impairment (Loss)	(139,414)	(139,414)
Beginning balance, Goodwill Net	150,909	150,733
Acquired goodwill, Net	41,993
Foreign currency translation, Net	223	176
Ending balance, Goodwill Net	$ 193,125	$ 150,909