Investments, At Equity, And Advances To 50% Or Less Owned Companies (Investments, At Equity, And Advances To 50% Or Less Owned Companies) (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Jun. 01, 2015
Schedule of Equity Method Investments [Line Items]
Equity Method Investments	$ 313,772	$ 331,103
Falcon Global [Member]
Schedule of Equity Method Investments [Line Items]
Ownership of equity interest	50.00%
OSV Partners [Member]
Schedule of Equity Method Investments [Line Items]
Ownership of equity interest	30.40%
Trailer Bridge Inc [Member]
Schedule of Equity Method Investments [Line Items]
Ownership of equity interest	55.30%
VA&E [Member]
Schedule of Equity Method Investments [Line Items]
Ownership of equity interest	41.30%		81.10%
Offshore Marine Services [Member] | MexMar [Member]
Schedule of Equity Method Investments [Line Items]
Ownership of equity interest	49.00%
Equity Method Investments	$ 63,404	50,163
Offshore Marine Services [Member] | Falcon Global [Member]
Schedule of Equity Method Investments [Line Items]
Ownership of equity interest	50.00%
Equity Method Investments	$ 18,539	17,951
Offshore Marine Services [Member] | Dynamic Offshore Drilling Ltd. [Member]
Schedule of Equity Method Investments [Line Items]
Ownership of equity interest	19.00%
Equity Method Investments	$ 15,871	14,172
Offshore Marine Services [Member] | Sea-Cat Crewzer II [Member]
Schedule of Equity Method Investments [Line Items]
Ownership of equity interest	50.00%
Equity Method Investments	$ 11,246	11,339
Offshore Marine Services [Member] | OSV Partners [Member]
Schedule of Equity Method Investments [Line Items]
Ownership of equity interest	30.40%
Equity Method Investments	$ 9,245	11,374
Offshore Marine Services [Member] | Nautical Power [Member]
Schedule of Equity Method Investments [Line Items]
Ownership of equity interest	50.00%
Equity Method Investments	$ 6,413	6,412
Offshore Marine Services [Member] | Sea Cat Crewzer [Member]
Schedule of Equity Method Investments [Line Items]
Ownership of equity interest	50.00%
Equity Method Investments	$ 4,088	2,701
Offshore Marine Services [Member] | Other Offshore Marine Services Joint Ventures [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investments	$ 9,505	15,898
Offshore Marine Services [Member] | Other Offshore Marine Services Joint Ventures [Member] | Minimum [Member]
Schedule of Equity Method Investments [Line Items]
Ownership of equity interest	20.00%
Offshore Marine Services [Member] | Other Offshore Marine Services Joint Ventures [Member] | Maximum [Member]
Schedule of Equity Method Investments [Line Items]
Ownership of equity interest	50.00%
Offshore Marine Services [Member] | Offshore Marine Services Joint Ventures [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investments	$ 138,311	130,010
Inland River Services [Member] | SCFCo Holdings [Member]
Schedule of Equity Method Investments [Line Items]
Ownership of equity interest	50.00%
Equity Method Investments	$ 46,028	57,437
Inland River Services [Member] | Bunge-SCF Grain [Member]
Schedule of Equity Method Investments [Line Items]
Ownership of equity interest	50.00%
Equity Method Investments	$ 16,176	16,695
Inland River Services [Member] | SCF Bunge Marine [Member]
Schedule of Equity Method Investments [Line Items]
Ownership of equity interest	50.00%
Equity Method Investments	$ 4,233	4,544
Inland River Services [Member] | Other Inland River Joint Ventures [Member]
Schedule of Equity Method Investments [Line Items]
Ownership of equity interest	50.00%
Equity Method Investments	$ 2,744	2,687
Inland River Services [Member] | Inland River Joint Venture [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investments	$ 69,181	81,363
Shipping Services [Member] | Trailer Bridge Inc [Member]
Schedule of Equity Method Investments [Line Items]
Ownership of equity interest	55.30%
Equity Method Investments	$ 43,050	41,710
Shipping Services [Member] | Sea-Access [Member]
Schedule of Equity Method Investments [Line Items]
Ownership of equity interest	50.00%
Equity Method Investments	$ 0	8,414
Shipping Services [Member] | SeaJon [Member]
Schedule of Equity Method Investments [Line Items]
Ownership of equity interest	50.00%
Equity Method Investments	$ 8,570	7,987
Shipping Services [Member] | SeaJon II [Member]
Schedule of Equity Method Investments [Line Items]
Ownership of equity interest	50.00%
Equity Method Investments	$ 0	6,388
Shipping Services [Member] | Shipping Services Joint Ventures [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investments	51,620	64,499
Corporate and Other [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investments	$ 54,660	55,231
Corporate and Other [Member] | Hawker Pacific Airservices Limited [Member]
Schedule of Equity Method Investments [Line Items]
Ownership of equity interest	34.20%
Equity Method Investments	$ 20,418	20,964
Corporate and Other [Member] | VA&E [Member]
Schedule of Equity Method Investments [Line Items]
Ownership of equity interest	41.30%
Equity Method Investments	$ 11,133	13,954
Corporate and Other [Member] | Avion Pacific Limited [Member]
Schedule of Equity Method Investments [Line Items]
Ownership of equity interest	39.10%
Equity Method Investments	$ 14,783	11,994
Corporate and Other [Member] | Cleancor [Member]
Schedule of Equity Method Investments [Line Items]
Ownership of equity interest	50.00%
Equity Method Investments	$ 5,373	5,613
Corporate and Other [Member] | Other Corporate Joint Ventures [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investments	$ 2,953	$ 2,706
Corporate and Other [Member] | Other Corporate Joint Ventures [Member] | Minimum [Member]
Schedule of Equity Method Investments [Line Items]
Ownership of equity interest	34.00%
Corporate and Other [Member] | Other Corporate Joint Ventures [Member] | Maximum [Member]
Schedule of Equity Method Investments [Line Items]
Ownership of equity interest	50.00%