Operating Segments (Reconciliation Of Totals Reported For Operating Segments) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Operating Segments [Abstract]
Revenues	$ 53,801	$ 68,026
Voyage Expenses	43,077	52,211
Amortization Expense	3,079	5,187
Gross Voyage Profit (Loss) (excluding Depreciation Expense)	7,787	11,521
Vessel Depreciation	5,436	5,543
Other Depreciation	225	184
Gross Profit	2,126	5,794
Administrative and General Expenses	4,513	5,022
Impairment Loss	1,934
Loss on Sale of Assets		68
Less: Net Income of Unconsolidated Entities	142	893
Total Other Operating Expenses	6,589	5,983
Operating Loss	$ (4,463)	$ (189)