Goodwill and Intangible Assets - Goodwill (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended	12 Months Ended
	Mar. 31, 2013	Dec. 31, 2012
Goodwill And Intangible Assets Disclosure [Abstract]
Goodwill gross carrying amount, Beginning balance	$ 290,147	$ 279,498
Acquired goodwill, gross		9,989
Foreign currency translation	(393)	660
Goodwill gross carrying amount, Ending balance	289,754	290,147
Accumulated Impairment Loss, Beginning balance	(139,414)	(139,414)
Acquired goodwill, impairment loss
Foreign currency translation
Accumulated Impairment Loss, Ending balance	(139,414)	(139,414)
Goodwill, net, Beginning balance	150,733	140,084
Acquired goodwill, net		9,989
Foreign currency translation, net	(393)	660
Goodwill, net, Ending balance	$ 150,340	$ 150,733