Derivative Instrument (Notional Table) (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 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	63,000	60,000
Designated as Hedging Instrument [Member] | Net Investment Hedging [Member] | CAD
Derivatives Fair Value [Line Items]
Derivative, Notional Amount	900,000	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	37,000	47,000
Not Designated as Hedging Instrument [Member] | GBP
Derivatives Fair Value [Line Items]
Derivative, Notional Amount	$ 20,100	$ 0