Derivative Instruments And Hedging Strategies (Recognized Gains (Losses) On Derivative Instruments Not Designated As Hedging Instruments) (Details) (USD $)	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013
Derivative [Line Items]
Derivative gains (losses), net	$ (2,681,000)	$ (3,235,000)
Options On Equities And Equity Indices [Member]
Derivative [Line Items]
Derivative gains (losses), net	22,000	(4,132,000)
Forward Currency Exchange, Option And Future Contracts [Member]
Derivative [Line Items]
Derivative gains (losses), net	62,000	(439,000)
Interest Rate Swap Agreements [Member]
Derivative [Line Items]
Derivative gains (losses), net	(169,000)	253,000
Commodity Contract [Member]
Derivative [Line Items]
Derivative gains (losses), net	(2,996,000)	368,000
Commodity Swap, Option And Future Contracts, Non-Exchange Traded [Member]
Derivative [Line Items]
Derivative gains (losses), net	400,000	715,000
Not Designated as Hedging Instrument [Member] | Forward Currency Exchange, Option And Future Contracts [Member]
Derivative [Line Items]
Derivative, Notional Amount	3,500,000
Not Designated as Hedging Instrument [Member] | Interest Rate Swap Agreements [Member]
Derivative [Line Items]
Derivative, Lower Fixed Interest Rate Range	3.00%
Derivative, Higher Fixed Interest Rate Range	3.05%
Derivative, Notional Amount	32,300,000
Not Designated as Hedging Instrument [Member] | Dynamic Offshore Drilling Ltd [Member] | Interest Rate Swap Agreements [Member]
Derivative [Line Items]
Derivative, Fixed Interest Rate	1.30%
Derivative, Notional Amount	95,800,000
Not Designated as Hedging Instrument [Member] | OSV Partners [Member] | Interest Rate Swap Agreements [Member]
Derivative [Line Items]
Derivative, Lower Fixed Interest Rate Range	1.89%
Derivative, Higher Fixed Interest Rate Range	2.27%
Derivative, Notional Amount	32,600,000
Not Designated as Hedging Instrument [Member] | Sea Cat Crewzer [Member] | Interest Rate Swap Agreements [Member]
Derivative [Line Items]
Derivative, Fixed Interest Rate	1.48%
Derivative, Notional Amount	15,700,000
Not Designated as Hedging Instrument [Member] | Dorian LPG [Member] | Interest Rate Swap Agreements [Member]
Derivative [Line Items]
Derivative, Lower Fixed Interest Rate Range	2.96%
Derivative, Higher Fixed Interest Rate Range	5.40%
Derivative, Notional Amount	$ 122,600,000