Intangible Assets - Estimated Future Amortization Expense for Amortizable Intangible Assets (Detail) $ in Millions	Sep. 30, 2015 USD ($)
Goodwill and Intangible Assets Disclosure [Abstract]
Estimated amortization expense 2015	$ 41.8
Estimated amortization expense 2016	141.5
Estimated amortization expense 2017	127.7
Estimated amortization expense 2018	120.2
Estimated amortization expense 2019	$ 115.3