Investments, At Equity, And Advances To 50% Or Less Owned Companies (Narrative) (Details) $ in Millions	3 Months Ended
	Mar. 31, 2016 USD ($)
Schedule Of Equity Method Investments [Line Items]
Guarantor Obligations, Maximum Exposure, Undiscounted	$ 2.7
Allocable Share of Uncalled Capital	1.9
Falcon Global [Member]
Schedule Of Equity Method Investments [Line Items]
Partners' Capital Account, Contributions	4.3
SCFCo Holdings [Member]
Schedule Of Equity Method Investments [Line Items]
Partners' Capital Account, Contributions	0.3
Outstanding Working Capital Advances At End Of Period	26.1
Sea-Access [Member]
Schedule Of Equity Method Investments [Line Items]
Proceeds from Equity Method Investment, Dividends or Distributions, Return of Capital	1.5
Partners' Capital Account, Return of Capital	1.1
Seajon [Member]
Schedule Of Equity Method Investments [Line Items]
Proceeds from Equity Method Investment, Dividends or Distributions, Return of Capital	0.6
Avion Pacific Limited [Member]
Schedule Of Equity Method Investments [Line Items]
Outstanding Working Capital Advances At End Of Period	3.0
Payments for Advance to Affiliate	(3.0)
VA&E [Member]
Schedule Of Equity Method Investments [Line Items]
Outstanding Working Capital Advances At End Of Period	3.6
Line of Credit Facility, Maximum Borrowing Capacity	6.0
Proceeds from Unsecured Lines of Credit	2.1
Repayments of Long-term Lines of Credit	(5.5)
Other Corporate Joint Ventures [Member]
Schedule Of Equity Method Investments [Line Items]
Payments for Advance to Affiliate	0.4
Other Offshore Marine Services Joint Ventures [Member]
Schedule Of Equity Method Investments [Line Items]
Guarantor Obligations, Maximum Exposure, Undiscounted	$ 55.2