Schedule of Unused Lines of Committed Credit Facilities (Detail) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Line of Credit Facility [Line Items]
Unused lines of credit	$ 763.2	$ 831.4
Within one year
Line of Credit Facility [Line Items]
Unused lines of credit		58.4
Later than one year and not later than two years
Line of Credit Facility [Line Items]
Unused lines of credit		8.0
Later than two years and not later than three years
Line of Credit Facility [Line Items]
Unused lines of credit	96.7	35.0
Later than three years and not later than five years
Line of Credit Facility [Line Items]
Unused lines of credit	$ 666.5	$ 730.0

Within one year

Later than one year and not later than two years

Later than two years and not later than three years

Later than three years and not later than five years