Defined Contribution Plans - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
United States Pension Plans Of US Entity, Defined Contribution [Member] | UNITED STATES
Defined Contribution Plan Disclosure [Line Items]
Expense recognized	$ 26.5	$ 25.3	$ 22.6
Supplemental matching	4.8	4.3	4.0
Foreign Pension Plans, Defined Contribution [Member] | UNITED KINGDOM
Defined Contribution Plan Disclosure [Line Items]
Expense recognized	$ 4.0	$ 4.5	$ 4.0