Acquired Intangible Assets and Related Amortization (Detail) (USD $) In Millions, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Finite-Lived Intangible Assets [Line Items]
Acquired intangible assets, net	$ 238.0	$ 253.6
Client relationships
Finite-Lived Intangible Assets [Line Items]
Acquired intangible assets, gross	216.5	217.9
Accumulated amortization	(65.4)	(58.6)
Acquired intangible assets, net	151.1	159.3
Trade secrets
Finite-Lived Intangible Assets [Line Items]
Acquired intangible assets, gross	31.4	31.3
Accumulated amortization	(14.7)	(13.4)
Acquired intangible assets, net	16.7	17.9
Software
Finite-Lived Intangible Assets [Line Items]
Acquired intangible assets, gross	70.7	70.9
Accumulated amortization	(28.7)	(25.1)
Acquired intangible assets, net	42.0	45.8
Trade names
Finite-Lived Intangible Assets [Line Items]
Acquired intangible assets, gross	28.2	28.1
Accumulated amortization	(9.6)	(9.0)
Acquired intangible assets, net	18.6	19.1
Other Intangible Assets
Finite-Lived Intangible Assets [Line Items]
Acquired intangible assets, gross	24.6	24.6
Accumulated amortization	(15.0)	(13.1)
Acquired intangible assets, net	$ 9.6	$ 11.5