Operating Segments (Segment Profit And Loss) (Details) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2015 USD ($)	Sep. 30, 2014 USD ($)	Sep. 30, 2015 USD ($) segment	Sep. 30, 2014 USD ($)
Segment Reporting Information [Line Items]
Number of operating segments \| segment			6
Fixed Revenue	$ 45,654	$ 58,763	$ 143,936	$ 172,452
Variable Revenue	20,855	15,647	57,907	51,404
Total Revenues	66,509	74,410	201,843	223,856
Voyage Expenses	52,569	55,450	158,589	170,685
Amortization Expenses	3,657	6,142	13,192	16,791
(Income) Loss of Unconsolidated Entities	(158)	176	(1,716)	364
Gross Voyage Profit (Loss) (excluding Depreciation Expense)	$ 10,441	$ 12,642	$ 31,778	$ 36,016
Gross Voyage Profit Margin Percentage (in hundredths)	16.00%	17.00%	16.00%	16.00%
Jones Act [Member]
Segment Reporting Information [Line Items]
Fixed Revenue	$ 19,199	$ 32,101	$ 63,344	$ 94,408
Total Revenues	19,199	32,101	63,344	94,408
Voyage Expenses	17,342	20,541	52,634	65,226
Amortization Expenses	2,450	4,799	9,392	12,144
Gross Voyage Profit (Loss) (excluding Depreciation Expense)	$ (593)	$ 6,761	$ 1,318	$ 17,038
Gross Voyage Profit Margin Percentage (in hundredths)	(3.00%)	21.00%	2.00%	18.00%
PCTC [Member]
Segment Reporting Information [Line Items]
Fixed Revenue	$ 13,131	$ 15,290	$ 41,890	$ 46,200
Variable Revenue	8,665	3,520	24,854	11,319
Total Revenues	21,796	18,810	66,744	57,519
Voyage Expenses	16,228	15,606	51,289	48,417
Amortization Expenses	604	593	2,095	1,938
Gross Voyage Profit (Loss) (excluding Depreciation Expense)	$ 4,964	$ 2,611	$ 13,360	$ 7,164
Gross Voyage Profit Margin Percentage (in hundredths)	23.00%	14.00%	20.00%	12.00%
Dry Bulk Carriers [Member]
Segment Reporting Information [Line Items]
Fixed Revenue	$ 1,933	$ 1,910	$ 5,667	$ 5,194
Variable Revenue	1,695	1,786	4,063	8,881
Total Revenues	3,628	3,696	9,730	14,075
Voyage Expenses	2,305	2,870	6,821	9,820
Amortization Expenses	60	63	181	172
(Income) Loss of Unconsolidated Entities	45	373	(797)	542
Gross Voyage Profit (Loss) (excluding Depreciation Expense)	$ 1,218	$ 390	$ 3,525	$ 3,541
Gross Voyage Profit Margin Percentage (in hundredths)	34.00%	11.00%	36.00%	25.00%
Rail-Ferry Service [Member]
Segment Reporting Information [Line Items]
Variable Revenue	$ 10,402	$ 9,435	$ 28,014	$ 27,101
Total Revenues	10,402	9,435	28,014	27,101
Voyage Expenses	8,038	7,644	22,514	22,089
Amortization Expenses	258	259	679	675
(Income) Loss of Unconsolidated Entities	229	81	186	148
Gross Voyage Profit (Loss) (excluding Depreciation Expense)	$ 1,877	$ 1,451	$ 4,635	$ 4,189
Gross Voyage Profit Margin Percentage (in hundredths)	18.00%	15.00%	17.00%	15.00%
Specialty Contracts [Member]
Segment Reporting Information [Line Items]
Fixed Revenue	$ 11,391	$ 9,462	$ 33,035	$ 26,650
Variable Revenue	541	1,497	1,373	4,624
Total Revenues	11,932	10,959	34,408	31,274
Voyage Expenses	9,435	9,923	26,654	26,964
Amortization Expenses	285	428	845	1,862
(Income) Loss of Unconsolidated Entities	(432)	(278)	(1,105)	(326)
Gross Voyage Profit (Loss) (excluding Depreciation Expense)	$ 2,644	$ 886	$ 8,014	$ 2,774
Gross Voyage Profit Margin Percentage (in hundredths)	22.00%	8.00%	23.00%	9.00%
Other [Member]
Segment Reporting Information [Line Items]
Variable Revenue	$ (448)	$ (591)	$ (397)	$ (521)
Total Revenues	(448)	(591)	(397)	(521)
Voyage Expenses	(779)	(1,134)	(1,323)	(1,831)
Gross Voyage Profit (Loss) (excluding Depreciation Expense)	$ 331	$ 543	$ 926	$ 1,310

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Amount of fixed revenue from external customers for the reportable segment. Such disclosure is presented if the amount is: (a) included in the measure of segment profit or loss reviewed by the chief operating decision maker or (b) otherwise regularly provided to the chief operating decision maker, even if not included in that measure of segment profit or loss.

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Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss).

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