Borrowings - Interest Expense Amounts Related to Convertible Notes (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Debt Disclosure [Abstract]
Interest cost related to contractual interest coupon	$ 15.5	$ 15.5	$ 15.5
Interest cost related to amortization of the discount	$ 13.2	$ 12.2	$ 11.3