Fair Value Measurements (Non-Financial Assets And Liabilities Measured At Fair Value) (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Asset Impairment Charges	$ 3,000,000	$ 1,200,000	$ 100,000
U.S.-flag Harbor Tugs [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Asset Impairment Charges	3,000,000
Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets Held-for-sale, Long Lived	17,494,000	0
Fair Value, Inputs, Level 1 [Member] | C-Lift LLC [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity Method Investments, Fair Value Disclosure	0
Fair Value, Inputs, Level 1 [Member] | Dorian LPG [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity Method Investments, Fair Value Disclosure	0
Fair Value, Inputs, Level 1 [Member] | Zhuhai SEACOR/Avion Logistics Company Limited [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment in affiliates (included in Investments, at Equity, and Advances to 50% or Less Owned Companies)	0
Fair Value, Inputs, Level 1 [Member] | Illinois Corn Processing LLC [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment in affiliates (included in Investments, at Equity, and Advances to 50% or Less Owned Companies)		0
Fair Value, Inputs, Level 1 [Member] | Witt O'Brien's LLC [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment in affiliates (included in Investments, at Equity, and Advances to 50% or Less Owned Companies)		0
Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets Held-for-sale, Long Lived	0	8,400,000
Fair Value, Inputs, Level 2 [Member] | C-Lift LLC [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity Method Investments, Fair Value Disclosure	13,290,000
Fair Value, Inputs, Level 2 [Member] | Dorian LPG [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity Method Investments, Fair Value Disclosure	14,989,000
Fair Value, Inputs, Level 2 [Member] | Zhuhai SEACOR/Avion Logistics Company Limited [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment in affiliates (included in Investments, at Equity, and Advances to 50% or Less Owned Companies)	924,000
Fair Value, Inputs, Level 2 [Member] | Illinois Corn Processing LLC [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment in affiliates (included in Investments, at Equity, and Advances to 50% or Less Owned Companies)		30,916,000
Fair Value, Inputs, Level 2 [Member] | Witt O'Brien's LLC [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment in affiliates (included in Investments, at Equity, and Advances to 50% or Less Owned Companies)		50,261,000
Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets Held-for-sale, Long Lived	0	0
Fair Value, Inputs, Level 3 [Member] | C-Lift LLC [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity Method Investments, Fair Value Disclosure	0
Fair Value, Inputs, Level 3 [Member] | Dorian LPG [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity Method Investments, Fair Value Disclosure	0
Fair Value, Inputs, Level 3 [Member] | Zhuhai SEACOR/Avion Logistics Company Limited [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment in affiliates (included in Investments, at Equity, and Advances to 50% or Less Owned Companies)	0
Fair Value, Inputs, Level 3 [Member] | Illinois Corn Processing LLC [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment in affiliates (included in Investments, at Equity, and Advances to 50% or Less Owned Companies)		0
Fair Value, Inputs, Level 3 [Member] | Witt O'Brien's LLC [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment in affiliates (included in Investments, at Equity, and Advances to 50% or Less Owned Companies)		$ 0