Deferred Dry-Docking Costs (Dry-Docking Costs Incurred And Amortization) (Details) (USD $) In Thousands			3 Months Ended		9 Months Ended
	Sep. 30, 2011	Dec. 31, 2010	Sep. 30, 2011 Deferred Dry-Docking Costs [Member]	Sep. 30, 2010 Deferred Dry-Docking Costs [Member]	Sep. 30, 2011 Deferred Dry-Docking Costs [Member]	Sep. 30, 2010 Deferred Dry-Docking Costs [Member]
Deferred Dry-Docking Costs [Line Items]
Net book value at beginning of period	$ 21,248	$ 20,429	$ 16,766	$ 34,123	$ 13,609	$ 41,825
Additions for the period			1,894		9,592	2,169
Reclassifications to assets held for sale				(8,090)		(9,761)
Reductions related to the sale of investment in subsidiaries			(837)		(837)
Amortization expense for the period			(2,076)	(3,966)	(6,617)	(12,166)
Net book value at end of period	$ 21,248	$ 20,429	$ 15,747	$ 22,067	$ 15,747	$ 22,067