Property and Equipment, net - Interest Cost Capitalized and Depreciation and Amortization Expense for Property and Equipment (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Property, Plant and Equipment [Abstract]
Interest cost capitalized	$ 10.3	$ 11.0	$ 5.4
Depreciation and amortization expense for property and equipment	$ 107.0	$ 88.2	$ 89.1