Derivative Instruments (Details) - USD ($) $ in Millions	Sep. 30, 2015	Dec. 31, 2014
Derivatives, Fair Value [Line Items]
Notional amount of foreign currency derivatives	$ 172.2	$ 238.7
Cash flow hedges [Member]
Derivatives, Fair Value [Line Items]
Notional amount of foreign currency derivatives	116.3	160.7
Non-designated derivatives [Member]
Derivatives, Fair Value [Line Items]
Notional amount of foreign currency derivatives	$ 55.9	$ 78.0