Derivative Instruments And Hedging Strategies (Recognized Gains (Losses) On Derivative Instruments Not Designated As Hedging Instruments) (Details) $ in Thousands, € in Millions	6 Months Ended
	Jun. 30, 2016 USD ($)	Jun. 30, 2015 USD ($)	Jun. 30, 2016 EUR (€)
Derivative [Line Items]
Derivative gains (losses), net	$ 1,065	$ (1,570)
Derivative, Fixed Interest Rate	(0.027%)		(0.027%)
Derivative, Notional Amount	$ 16,700		€ 15.0
Options on equities and equity indices
Derivative [Line Items]
Derivative gains (losses), net	3,079	(442)
Forward Currency Exchange, Option And Future Contracts [Member]
Derivative [Line Items]
Derivative gains (losses), net	(107)	(302)
Interest rate swap agreements
Derivative [Line Items]
Derivative gains (losses), net	(18)	(5)
Commodity swap, option and future contracts, exchange traded
Derivative [Line Items]
Derivative gains (losses), net	671	(2,271)
Commodity swap, option and future contracts, non-exchange traded
Derivative [Line Items]
Derivative gains (losses), net	0	1,450
Not Designated as Hedging Instrument [Member] | Forward Currency Exchange, Option And Future Contracts [Member]
Derivative [Line Items]
Derivative, Notional Amount	2,100
Not Designated as Hedging Instrument [Member] | OSV Partners [Member] | Interest rate swap agreements
Derivative [Line Items]
Derivative, Notional Amount	$ 40,600
Derivative, Lower Fixed Interest Rate Range	1.89%		1.89%
Derivative, Higher Fixed Interest Rate Range	2.27%		2.27%
Not Designated as Hedging Instrument [Member] | Dynamic Offshore Drilling Ltd [Member] | Interest rate swap agreements
Derivative [Line Items]
Derivative, Fixed Interest Rate	1.30%		1.30%
Derivative, Notional Amount	$ 78,800
Not Designated as Hedging Instrument [Member] | Falcon Global [Member] | Interest rate swap agreements
Derivative [Line Items]
Derivative, Fixed Interest Rate	2.06%		2.06%
Derivative, Notional Amount	$ 62,500
Three Point Seven Five Percentage Convertible Notes [Member]
Derivative [Line Items]
Embedded Derivative, Gain on Embedded Derivative	$ (2,560)	$ 0