Derivative Instruments and Hedging Activities - Derivative Instruments Designated as Fair Value Hedges (Detail) - Interest Rate Swaps [Member] - Interest Expense [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Gain (Loss) on Instrument	$ 7.5	$ 2.8	$ 14.7
Gain (Loss) on Hedged Item	$ (7.5)	$ (2.8)	$ (14.7)