Derivatives Instruments (Notional Table) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Designated as Hedging Instrument [Member] | Cash Flow Hedging [Member] | USD
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	$ 57,000	$ 57,000
Designated as Hedging Instrument [Member] | Cash Flow Hedging [Member] | CAD
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	72,000	58,000
Designated as Hedging Instrument [Member] | Cash Flow Hedging [Member] | GBP
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	60,000	40,000
Designated as Hedging Instrument [Member] | Net Investment Hedging [Member] | CAD
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	1,175,000	900,000
Designated as Hedging Instrument [Member] | Net Investment Hedging [Member] | GBP
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	550,000	350,000
Not Designated as Hedging Instrument [Member] | USD
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	47,000	12,000
Not Designated as Hedging Instrument [Member] | Net Investment Hedging [Member] | CAD
Derivatives, Fair Value [Line Items]
Notional Amount of Nonderivative Instruments	250,000	250,000
Not Designated as Hedging Instrument [Member] | Net Investment Hedging [Member] | GBP
Derivatives, Fair Value [Line Items]
Notional Amount of Nonderivative Instruments	$ 1,050,000	$ 1,050,000