Derivatives - Effect of Our Derivative Financial Instruments on Our Consolidated Statements of Operations (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Derivatives in cash flow hedging relationships:
Gain (Loss) recognized in Other Comprehensive Income (Loss) on derivatives	$ 2.6	$ (3.9)	$ (8.1)	$ (5.5)
Interest
Derivatives in cash flow hedging relationships:
Loss reclassified from Accumulated Other Comprehensive Income (Loss) into income (effective portion)	$ 1.3	$ 1.3	3.9	3.5
Loss recognized in income on derivatives (ineffective portion and amount excluded from effectiveness testing)			$ (0.1)	$ (0.5)