Property and Equipment - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Property, Plant and Equipment [Line Items]
Rent expense on operating leases	$ 37.9	$ 36.7	$ 33.2
Minimum [Member]
Property, Plant and Equipment [Line Items]
Operating leases offer extension options period	1 month
Maximum [Member]
Property, Plant and Equipment [Line Items]
Operating leases offer extension options period	5 years