Aggregate Minimum Payments under Operating Leases with Initial or Remaining Terms of More Than One Year (Detail) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012
Schedule of Operating Leases [Line Items]
2013	$ 27.7
2014	30.5
2015	27.9
2016	23.8
2017	22.5
2018 and thereafter	$ 151.3