Derivative Instruments And Hedging Strategies (Narrative) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013
Offshore Marine Services Joint Ventures [Member]
Derivative [Line Items]
Derivative, Notional Amount	$ 16.8
Fixed interest rate	1.48%
Inland River Joint Venture [Member] | Cash Flow Hedging [Member]
Derivative [Line Items]
Derivative, Notional Amount	28.6
Inland River Joint Venture [Member] | Minimum [Member]
Derivative [Line Items]
Fixed interest rate	1.53%
Inland River Joint Venture [Member] | Maximum [Member]
Derivative [Line Items]
Fixed interest rate	4.16%
Shipping Services Joint Ventures [Member]
Derivative [Line Items]
Fixed interest rate	2.79%
Shipping Services Joint Ventures [Member] | Cash Flow Hedging [Member]
Derivative [Line Items]
Derivative, Notional Amount	37.3
Not Designated as Hedging Instrument [Member] | Forward Currency Exchange, Option And Future Contracts [Member]
Derivative [Line Items]
Derivative, Notional Amount	25.9
Not Designated as Hedging Instrument [Member] | Interest Rate Swap [Member]
Derivative [Line Items]
Derivative, Notional Amount	88.2
Fixed interest rate range, start	2.25%
Fixed interest rate range, end	3.05%
Not Designated as Hedging Instrument [Member] | Offshore Marine Services Joint Ventures [Member] | Interest Rate Swap [Member]
Derivative [Line Items]
Derivative, Notional Amount	103.1
Fixed interest rate	1.30%
Not Designated as Hedging Instrument [Member] | Shipping Services Joint Ventures [Member] | Cash Flow Hedging [Member]
Derivative [Line Items]
Fixed interest rate range, start	2.96%
Fixed interest rate range, end	5.40%
Not Designated as Hedging Instrument [Member] | Shipping Services Joint Ventures [Member] | Interest Rate Swap [Member]
Derivative [Line Items]
Derivative, Notional Amount	$ 130.7