Derivative Instrument (Notional Table) (Details) - USD ($) $ in Thousands		3 Months Ended	12 Months Ended
		Mar. 31, 2016	Dec. 31, 2015
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	72,000
Designated as Hedging Instrument [Member] | Cash Flow Hedging [Member] | GBP
Derivatives Fair Value [Line Items]
Derivative, Notional Amount		60,000	60,000
Designated as Hedging Instrument [Member] | Net Investment Hedging [Member] | CAD
Derivatives Fair Value [Line Items]
Derivative, Notional Amount		1,175,000	1,175,000
Notional Amount Of Nonderivative Instruments		250,000	250,000
Designated as Hedging Instrument [Member] | Net Investment Hedging [Member] | GBP
Derivatives Fair Value [Line Items]
Derivative, Notional Amount		550,000	550,000
Notional Amount Of Nonderivative Instruments		1,050,000	1,050,000
Not Designated as Hedging Instrument [Member] | CAD
Derivatives Fair Value [Line Items]
Derivative, Notional Amount	[1]	$ 47,000	$ 47,000

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