Derivative Instruments And Hedging Strategies (Recognized Gains (Losses) On Derivative Instruments Not Designated As Hedging Instruments) (Details) (USD $)	6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011
Derivative [Line Items]
Derivative gains (losses), net	$ (613,000)	$ (9,854,000)
Options On Equities And Equity Indices [Member]
Derivative [Line Items]
Derivative gains (losses), net	(910,000)	332,000
Forward Currency Exchange, Option And Future Contracts [Member]
Derivative [Line Items]
Derivative gains (losses), net	373,000	1,812,000
Interest Rate Swap Agreements [Member]
Derivative [Line Items]
Derivative gains (losses), net	(542,000)	(1,276,000)
Exchange Traded [Member]
Derivative [Line Items]
Derivative gains (losses), net	(1,456,000)	(3,547,000)
Commodity Swap, Option And Future Contracts, Non-Exchange Traded [Member]
Derivative [Line Items]
Derivative gains (losses), net	1,922,000	250,000
U.S. Treasury Notes, Rate Locks And Bond Future And Option Contracts [Member]
Derivative [Line Items]
Derivative gains (losses), net	0	(7,425,000)
Derivatives Not Designated As Hedging Instruments [Member]
Derivative [Line Items]
Notional Amount of Foreign Currency Derivatives	18,600,000
SEACOR Holdings Inc. [Member] | Derivatives Not Designated As Hedging Instruments [Member]
Derivative [Line Items]
Derivative, Lower Fixed Interest Rate Range	1.67%
Derivative, Higher Fixed Interest Rate Range	2.59%
Notional amount of interest rate derivatives	93,100,000
Offshore Marine Services Joint Ventures [Member]
Derivative [Line Items]
Notional amount of interest rate derivatives	$ 24,800,000
Offshore Marine Services Joint Ventures [Member] | Derivatives Not Designated As Hedging Instruments [Member]
Derivative [Line Items]
Derivative, Fixed Interest Rate	3.05%