Employee Benefit Plans - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Domestic Employees
Employee Benefit Plan [Line Items]
Employer contributions to plan	$ 9.7	$ 9.2	$ 8.8
Foreign Employees
Employee Benefit Plan [Line Items]
Employer contributions to plan	$ 6.0	$ 5.3	$ 6.2