Schedule of Amortizable Intangible Asset (Detail) (USD $) In Thousands, unless otherwise specified	9 Months Ended	12 Months Ended
	Sep. 30, 2013	Dec. 31, 2012
Finite-Lived Intangible Assets [Line Items]
Cost	$ 90,039	$ 90,039
Accumulated Amortization	(40,129)	(31,807)
Net Book Value	49,910	58,232
Customer related intangibles
Finite-Lived Intangible Assets [Line Items]
Cost	44,355	44,355
Accumulated Amortization	(16,838)	(13,142)
Net Book Value	27,517	31,213
Customer related intangibles | Maximum
Finite-Lived Intangible Assets [Line Items]
Range of Useful Lives	9 years	9 years
Technology
Finite-Lived Intangible Assets [Line Items]
Cost	43,446	43,446
Accumulated Amortization	(21,053)	(16,431)
Net Book Value	22,393	27,015
Technology | Minimum
Finite-Lived Intangible Assets [Line Items]
Range of Useful Lives	4 years	4 years
Technology | Maximum
Finite-Lived Intangible Assets [Line Items]
Range of Useful Lives	9 years	9 years
Other intangibles
Finite-Lived Intangible Assets [Line Items]
Cost	2,238	2,238
Accumulated Amortization	(2,238)	(2,234)
Net Book Value		$ 4
Other intangibles | Minimum
Finite-Lived Intangible Assets [Line Items]
Range of Useful Lives	1 year	1 year
Other intangibles | Maximum
Finite-Lived Intangible Assets [Line Items]
Range of Useful Lives	5 years	5 years