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, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Derivatives in cash flow hedging relationships:
(Loss) gain recognized in Other Comprehensive Income (Loss) on derivatives	$ (3.9)	$ 1.4	$ (5.5)	$ (0.7)
Loss recognized in income on derivatives (ineffective portion and amount excluded from effectiveness testing)			0.5
Interest
Derivatives in cash flow hedging relationships:
Loss reclassified from Accumulated Other Comprehensive Income (Loss) into income (effective portion)	$ 1.3	1.0	3.5	3.3
Loss recognized in income on derivatives (ineffective portion and amount excluded from effectiveness testing)		$ (0.1)	$ (0.5)	$ (1.4)