Pro Forma Condensed Consolidated Income Statement Information (Detail) (USD $) In Millions, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010
Business Acquisition, Pro Forma Information [Line Items]
Net service revenue	$ 1,502.6	$ 1,682.1
Operating (loss) income	(467.3)	219.0
Net (loss) income	$ (381.8)	$ 115.3
Basic (loss) earnings per share	$ (13.30)	$ 4.11
Diluted (loss) earnings per share	$ (13.30)	$ 4.05