Financial Instruments (Narrative) (Details) ₨ in Millions, PHP in Millions, COP in Millions, CAD in Millions, AUD in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2016 AUD	Mar. 31, 2016 INR (₨)	Mar. 31, 2016 COP	Mar. 31, 2016 CAD	Mar. 31, 2016 USD ($)	Mar. 31, 2016 PHP	Mar. 31, 2015 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
Derivatives
Derivative, Notional Amount					$ 1,005.9			$ 1,040.8
Derivative instruments maturity period (in months)	36 months	36 months	36 months	36 months	36 months	36 months
Deferred tax expense					$ (2.5)			(16.2)
Deferred gains (losses), net of tax					4.1		$ 13.6	26.1	$ 18.3
Deferred gain on derivative instruments reclassified from OCI to earnings during the next the next twelve months, before tax					(9.1)
Deferred gain on derivative instruments reclassified from OCI to earnings during next twelve months, net of tax					(5.6)
Derivative Instruments Not Designated as Hedging Instruments, Gain					1.0		$ 2.4
Derivative Instruments Not Designated as Hedging Instruments, Asset, at Fair Value					1.5
Aggregate fair value of derivative instruments in liability positions					19.3
Aggregate fair value of collateral already posted					0.0
Trading Securities, Fair Value Disclosure					11.2			$ 12.2
Forward Contracts PHP [Member]
Derivatives
Foreign currency acquired through forward exchange contracts | PHP						PHP 37,062.0
Derivative, Notional Amount					798.6
Forward Contracts INR [Member]
Derivatives
Foreign currency acquired through forward exchange contracts | ₨		₨ 11,322.0
Derivative, Notional Amount					158.8
Forward Contracts CAD [Member]
Derivatives
Foreign currency acquired through forward exchange contracts | CAD				CAD 35.2
Derivative, Notional Amount					27.9
Forward Contracts COP [Member]
Derivatives
Foreign currency acquired through forward exchange contracts | COP			COP 4,000.0
Derivative, Notional Amount					1.3
Forward Contracts AUD [Member]
Derivatives
Foreign currency acquired through forward exchange contracts | AUD	AUD 27.0
Derivative, Notional Amount					$ 19.3