Property and Equipment, net - Interest Cost Capitalized and Depreciation and Amortization Expense for Property and Equipment (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Property Plant And Equipment [Abstract]
Interest cost capitalized	$ 1.0	$ 2.0	$ 4.0	$ 4.5
Depreciation and amortization expense for property and equipment	$ 31.0	$ 36.6	$ 94.6	$ 112.2