Derivatives - Effect of Our Derivative Financial Instruments on Our Consolidated Statements of Operations (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Derivatives in cash flow hedging relationships:
Loss recognized in Other Comprehensive Income (Loss) on derivatives	$ (4.3)	$ 0.2	$ (11.0)	$ (1.6)
Interest
Derivatives in cash flow hedging relationships:
Loss reclassified from Accumulated Other Comprehensive Income (Loss) into income (effective portion)	$ 1.4	$ 1.2	2.8	2.3
Loss recognized in income on derivatives (ineffective portion and amount excluded from effectiveness testing)			$ (0.1)	$ (0.5)