Property and Equipment, net - Interest Cost Capitalized and Depreciation and Amortization Expense for Property and Equipment (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Property Plant And Equipment [Abstract]
Interest cost capitalized	$ 2.0	$ 1.0	$ 4.5	$ 3.7
Depreciation and amortization expense for property and equipment	$ 36.6	$ 38.1	$ 112.2	$ 121.2