Derivative Instruments And Hedging Strategies (Recognized Gains (Losses) On Derivative Instruments Designated As Cash Flow Hedges) (Details) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Derivative Instruments, Gain (Loss) [Line Items]
Derivative losses on cash flow hedges	$ (247,000)	$ (2,195,000)	$ (747,000)	$ (2,294,000)
Other Comprehensive Income (Loss), Reclassification Adjustment on Derivatives Included in Net Income, Net of Tax	857,000	103,000	1,591,000	851,000
Reclassification of derivative losses to interest expense or equity in earnings of 50% or less owned companies, Other comprehensive income (loss)			0	0
Derivative Instruments, Gain (Loss) Recognized in Other Comprehensive Income (Loss), Effective Portion, Net			844,000	(1,443,000)
Gains (losses) on derivative instruments designated as cash flow hedges, Derivative gains (losses), net			(19,000)	(27,000)
Other Comprehensive Income (Loss) [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Interest rate swap agreements, ineffective portion, Derivative gains (losses), net	0
Net Income [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) on Interest Rate Cash Flow Hedge Effective Portion, Net			0	0
Interest rate swap agreements, ineffective portion, Derivative gains (losses), net			(19,000)	(27,000)
SEACOR Holdings Inc. [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Notional Amount of Interest Rate Cash Flow Hedge Derivatives	125,000,000		125,000,000
Cash Flow Hedging [Member] | SEACOR Holdings Inc. [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Lower Fixed Interest Rate Range	2.25%		2.25%
Derivative, Higher Fixed Interest Rate Range	2.85%		2.85%
Offshore Marine Services Joint Ventures [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Notional Amount of Interest Rate Cash Flow Hedge Derivatives	18,900,000		18,900,000
Offshore Marine Services Joint Ventures [Member] | Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Fixed Interest Rate	1.48%		1.48%
Inland River Joint Venture [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Notional Amount of Interest Rate Cash Flow Hedge Derivatives	$ 46,600,000		$ 46,600,000
Inland River Joint Venture [Member] | Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Lower Fixed Interest Rate Range	1.53%		1.53%
Derivative, Higher Fixed Interest Rate Range	4.16%		4.16%