Other - Additional Information Domain (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended				3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Apr. 01, 2015	Apr. 01, 2014	Sep. 30, 2013 Minimum	Sep. 30, 2012 Minimum	Sep. 30, 2013 Northwind Holdings LLC [Member]	Sep. 30, 2013 Tailwind Holdings LLC [Member]	Mar. 31, 2012 Prior to UK Tax Rate Change [Member] Rate	Mar. 31, 2012 After UK Tax Rate Change [Member] Rate
Debt Instrument, Periodic Payment, Principal									$ 45.0
Repayments of Long-term Debt			101.2	45.6						62.5
Gains (Losses) on Extinguishment of Debt										4.0
Line of Credit Facility, term	five
Line of Credit Facility, Maximum Borrowing Capacity	400.0		400.0
Line of Credit Facility, Amount Outstanding	0		0
Unrecognized Tax Benefits	21.5		21.5
Unrecognized Tax Benefits That Would Not Effect Tax Rate	15.0		15.0
Unrecognized Tax Benefits, Income Tax Penalties and Interest Expense	0.1	0.1	0.3	(10.5)
2013 UK Tax rate	23.00%		23.00%
2014 UK Tax Rate						21.00%
2015 UK Tax Rate					20.00%
2012 UK tax rate											25.00%	24.00%
Income Tax Reconciliation, Change in Enacted Tax Rate							$ 6.3	$ 9.3