Property and Equipment, net - Interest Cost Capitalized and Depreciation and Amortization Expense for Property and Equipment (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Property Plant And Equipment [Abstract]
Interest cost capitalized		$ 1.2	$ 1.0	$ 2.5
Depreciation and amortization expense for property and equipment	$ 31.4	$ 38.5	$ 63.6	$ 75.6