Schedule of Amortizable Intangible Asset (Detail) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Finite-Lived Intangible Assets [Line Items]
Cost	$ 90,039	$ 90,039
Accumulated Amortization	(34,584)	(31,807)
Net Book Value	55,455	58,232
Customer related intangibles
Finite-Lived Intangible Assets [Line Items]
Cost	44,355	44,355
Accumulated Amortization	(14,374)	(13,142)
Net Book Value	29,981	31,213
Technology
Finite-Lived Intangible Assets [Line Items]
Cost	43,446	43,446
Accumulated Amortization	(17,972)	(16,431)
Net Book Value	25,474	27,015
Other intangibles
Finite-Lived Intangible Assets [Line Items]
Cost	2,238	2,238
Accumulated Amortization	(2,238)	(2,234)
Net Book Value		$ 4