Derivatives - Schedule of Gains (Losses) for Derivatives Designated as Fair Value Hedges (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Derivative Instruments Gain Loss [Line Items]
Total (gain) loss recognized as ineffectiveness in the Condensed Consolidated Statements of Operations	$ (0.2)	$ 0.1	$ (0.4)	$ (0.6)
Interest Rate Swap | Investment and other expense-net
Derivative Instruments Gain Loss [Line Items]
Total (gain) loss recognized as ineffectiveness in the Condensed Consolidated Statements of Operations	0.9	(1.6)	(1.4)	(1.7)
Hedged Items | Investment and other expense-net
Derivative Instruments Gain Loss [Line Items]
Total (gain) loss recognized as ineffectiveness in the Condensed Consolidated Statements of Operations	$ (1.1)	$ 1.7	$ 1.0	$ 1.1