Basis of Presentation - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Revisions [Line Items]
Fees and other revenues	$ 76.0	$ 78.4	$ 215.3	$ 213.5