Derivative Instruments and Hedging Activities - Gains (Losses) Relating to Derivative Instruments Recorded to Income (Parenthetical) (Detail) - Derivatives designated as hedging instruments [Member] $ in Millions	12 Months Ended
	Dec. 31, 2015 USD ($)
Derivative Instruments, Gain (Loss) [Line Items]
Benefit related to hedge ineffectiveness	$ 1.3
Expense related to amounts excluded from assessment of hedge effectiveness recognized in income (loss)	$ 0.9