Debt And Lease Obligations (Schedule of Debt Obligations) (Details)								1 Months Ended								3 Months Ended					12 Months Ended
		Apr. 06, 2016	Nov. 13, 2015	Nov. 12, 2015	Nov. 04, 2015	Nov. 03, 2015	Aug. 26, 2014 USD ($) item	Apr. 30, 2016	Apr. 30, 2015 USD ($)	Aug. 31, 2014 item	Jan. 31, 2012 USD ($)	Dec. 31, 2011 USD ($) item	Nov. 30, 2011 USD ($)	Jun. 30, 2011 USD ($) item	Aug. 31, 2010 USD ($) item	Mar. 31, 2016 USD ($)		Dec. 31, 2015 USD ($)		Mar. 31, 2015 USD ($)	Dec. 31, 2015 USD ($)		Jun. 20, 2011
Debt Instrument [Line Items]
Total principal due																$ 117,070,000		$ 159,844,000			$ 159,844,000
Less current maturities																(113,721,000)		(156,807,000)			(156,807,000)
Less: Debt Issuance Costs																(3,349,000)		(3,037,000)			(3,037,000)
Proceeds from borrowings of line of credit																				$ 5,000,000
Pre-funding of upcoming quarterly debt payment, amount																1,496,000		$ 1,530,000			$ 1,530,000
Related debt paid off																				13,500,000
Notes Payable - Variable Rate 2018, Tranche B [Member]
Debt Instrument [Line Items]
Debt instrument interst rate, minimum	[1]																				4.6947%
Subsequent Event [Member]
Debt Instrument [Line Items]
Increase in interest rate margins		50.00%
Loan Agreement [Member]
Debt Instrument [Line Items]
Related debt paid off																12,000,000
Handysize Vessel [Member]
Debt Instrument [Line Items]
Related debt paid off																				$ 13,500,000
Handysize Vessel [Member] | Dry Bulk Carriers [Member]
Debt Instrument [Line Items]
Related debt paid off																$ 25,100,000
ING Bank [Member]
Debt Instrument [Line Items]
Term of financing agreement in years														7 years
Number of tranches | item														2
ING Bank [Member] | LIBOR [Member]
Debt Instrument [Line Items]
Basis spread on variable interest rate					4.50%	2.50%
ING Bank [Member] | Notes Payable - Variable Rate 2018, Tranche A [Member]
Debt Instrument [Line Items]
Interest rate	[1]																	4.693%			4.693%
Maturity date	[1]															2018
Total principal due	[1]																	$ 8,589,000			$ 8,589,000
Term of financing agreement in years															7 years
Proceeds from borrowings of line of credit														$ 24,100,000
Number of tranches | item															2
ING Bank [Member] | Notes Payable - Variable Rate 2018, Tranche A [Member] | Dry Bulk Carriers [Member]
Debt Instrument [Line Items]
Business acquisition interest in acquiree																							100.00%
ING Bank [Member] | Notes Payable - Variable Rate 2018, Tranche B [Member]
Debt Instrument [Line Items]
Interest rate	[1]															4.9106%
Maturity date	[1]															2018
Total principal due	[1]															$ 1,851,000		$ 25,146,000			$ 25,146,000
Proceeds from borrowings of line of credit											$ 12,700,000		$ 6,100,000
ING Bank [Member] | Notes Payable - Variable Rate 2018, Tranche B [Member] | Maximum [Member]
Debt Instrument [Line Items]
Proceeds from borrowings of line of credit														$ 23,300,000
ING Bank [Member] | Notes Payable - Variable Rate 2018c [Member]
Debt Instrument [Line Items]
Interest rate	[1]																	4.8199%			4.8199%
Maturity date	[1]															2018
Total principal due	[1]																	$ 2,800,000			$ 2,800,000
ING Bank [Member] | Notes Payable - Variable Rate 2018 Tranche I [Member]
Debt Instrument [Line Items]
Secured term loan facility fully drawn amount															$ 36,800,000
ING Bank [Member] | Notes Payable - Variable Rate 2018 Tranche II [Member]
Debt Instrument [Line Items]
Secured term loan facility fully drawn amount															$ 18,400,000
ING Bank [Member] | Handysize Vessel [Member] | Notes Payable - Variable Rate 2018, Tranche A [Member]
Debt Instrument [Line Items]
Number of vessels financed | item															3
Number of vessels covered by Tranch I | item															2
Capital One N.A. [Member] | Notes Payable - Variable Rate 2017 [Member]
Debt Instrument [Line Items]
Interest rate	[2]															2.7885%		2.5938%			2.5938%
Maturity date	[2]															2017
Total principal due	[2]															$ 6,274,000		$ 6,904,000			$ 6,904,000
Debt instrument principal amount												$ 15,700,000
Debt instrument term, years																5 years
Final quarterly balloon payment												$ 4,700,000
Number of monthly payments | item												59
Regions Bank [Member] | Notes Payable - Variable Rate 2017 [Member]
Debt Instrument [Line Items]
Interest rate	[3]															9.69%		9.44%			9.44%
Maturity date	[3]															2017
Total principal due	[3]															$ 27,965,000		$ 33,090,000			$ 33,090,000
Regions Bank [Member] | Old Line Of Credit Facility [Member] | Term Loan [Member]
Debt Instrument [Line Items]
Debt instrument principal amount																45,000,000
Regions Bank [Member] | Old Line Of Credit Facility [Member] | Swingline Loans [Member]
Debt Instrument [Line Items]
Line of credit																$ 5,000,000
Regions Bank [Member] | Secured Line Of Credit [Member]
Debt Instrument [Line Items]
Interest rate	[3]															9.69%		9.44%			9.44%
Maturity date	[3]															2017
Total principal due	[3]															$ 31,000,000		$ 31,000,000			$ 31,000,000
Regions Bank [Member] | Senior Secured Credit Facility [Member] | LIBOR [Member] | July 1, 2016 through July 20, 2017 [Member]
Debt Instrument [Line Items]
Basis spread on variable interest rate			10.00%
Regions Bank [Member] | Senior Secured Credit Facility [Member] | Old Line Of Credit Facility [Member] | LIBOR [Member]
Debt Instrument [Line Items]
Basis spread on variable interest rate				3.50%
Regions Bank [Member] | Senior Secured Credit Facility [Member] | Old Line Of Credit Facility [Member] | LIBOR [Member] | November 13, 2015 through June 30, 2016 [Member]
Debt Instrument [Line Items]
Basis spread on variable interest rate			9.25%
Regions Bank [Member] | Revolving Credit Facility [Member] | Old Line Of Credit Facility [Member]
Debt Instrument [Line Items]
Line of credit																$ 40,000,000
DVB Bank SE [Member]
Debt Instrument [Line Items]
Interest rate									4.16%
Debt instrument term, years									5 years
Final quarterly balloon payment									$ 16,800,000
Amortization period									10 years
DVB Bank SE [Member] | Notes Payable - Fixed Rate 2020 [Member]
Debt Instrument [Line Items]
Interest rate					6.35%	4.35%										6.35%	[4]	6.35%	[4]		6.35%	[4]
Maturity date	[4]															2020
Total principal due	[4]															$ 32,348,000		$ 33,664,000			$ 33,664,000
Debt instrument principal amount							$ 38,500,000
Number of quarterly payments | item							24
Final quarterly balloon payment							$ 20,700,000
Pre-funding of upcoming quarterly debt payment, amount																$ 500,000
Citizens Asset Finance (formerly RBS Asset Finance) [Member] | Notes Payable - Variable Rate 2021 [Member]
Debt Instrument [Line Items]
Interest rate	[5]															4.1874%		3.99%			3.99%
Maturity date	[5]															2021
Total principal due	[5]															$ 17,632,000		$ 18,651,000			$ 18,651,000
Debt instrument principal amount																$ 23,000,000
Increase in interest rate margins																		1.00%
Number of monthly payments | item										84
Citizens Asset Finance (formerly RBS Asset Finance) [Member] | Notes Payable - Variable Rate 2021 [Member] | LIBOR [Member]
Debt Instrument [Line Items]
Basis spread on variable interest rate																2.75%
Citizens Asset Finance (formerly RBS Asset Finance) [Member] | Subsequent Event [Member] | Notes Payable - Variable Rate 2021 [Member]
Debt Instrument [Line Items]
Increase in interest rate margins								0.50%

[1] We entered into a variable rate financing agreement with ING Bank N.V, London branch in August 2010 for a seven year facility to finance the construction and acquisition of three handysize vessels. Pursuant to the terms of the facility, the lender agreed to provide a secured term loan facility divided into two tranches which corresponded to the vessel delivery schedule. Tranche I covered the first two vessels delivered with Tranche II covering the last vessel. Tranche I was fully drawn in the amount of $36.8 million, and Tranche II fully drawn at $18.4 million We entered into a variable rate financing agreement with ING Bank N.V., London branch in June 2011 for a seven year facility to finance the acquisition of a capesize vessel and a supramax bulk carrier newbuilding, both of which we acquired a 100% interest in as a result of our acquisition of Dry Bulk. Pursuant to the terms of the facility, the lender agreed to provide a secured term loan facility divided into two tranches: Tranche A, fully drawn in June 2011 in the amount of $24.1 million, and Tranche B, providing up to $23.3 million of additional credit. Under Tranche B, we drew $6.1 million in November 2011 and $12.7 million in January 2012. In order to aid in the collateral value coverage covenant, both of the above facilities were merged into one facility without altering the debt maturities or terms of our indebtedness. Effective November 4, 2015, the interest rate was increased from LIBOR plus 2.5% to LIBOR plus 4.5%. For other changes to the credit facility, refer to "Recent Financing Agreement Waivers and Amendments" within Note F - Debt Obligations of our Annual Report on Form 10-K for the year ended December 31, 2015.

[2] In December 2011, we entered into a variable rate financing agreement with Capital One N.A. for a five year facility totaling $15.7 million to finance a portion of the acquisition price of a multi-purpose ice strengthened vessel. This loan requires us to make 59 monthly payments with a final balloon payment of $4.7 million in January 2017.

[3] Our original senior secured Credit Facility was scheduled to mature on September 24, 2018 and included a term loan facility in the principal amount of $45.0 million and a LOC in the principal amount of up to $40.0 million. The LOC facility originally included a $20.0 million sublimit for the issuance of standby letters of credit and a $5.0 million sublimit for swingline loans. As discussed above, o

[4] We entered into a fixed rate financing agreement with DVB Bank SE, on August 26, 2014 in the amount of $38.5 million, collateralized by our 2007 PCTC at a rate of 4.35% with 24 quarterly payments and a final balloon payment of $20.7 million in August 2020. This loan requires us to pre-fund a one-third portion of the upcoming quarterly scheduled debt payment, which, at March 31, 2016, constituted $0.5 million and is included as restricted cash on our Condensed Consolidated Balance Sheet.

[5] We have a $23.0 million loan with Citizens Asset Finance (formerly RBS Asset Finance) that is collateralized by one of our 1999 PCTCs at a variable rate equal to the 30-day Libor rate plus 2.75% payable in 84 monthly installments with the final payment due August 2021. Late in 2015, this loan agreement was amended to include an increase to the annual interest rate of 1.0% and in April 2016 this loan agreement was further amended to include an additional increase to the annual interest rate of 0.5%. For additional changes to this facility, refer to "Recent Financing Agreement Waivers and Amendments" within Note F - Debt Obligations of our Annual Report on Form 10-K for the year ended December 31, 2015