Subsequent Event (Details) $ in Thousands		1 Months Ended	3 Months Ended	9 Months Ended
	Nov. 06, 2015 USD ($) item	Oct. 31, 2015 USD ($) item	Sep. 30, 2015 USD ($)	Sep. 30, 2015 USD ($) loan	Oct. 21, 2015 segment item
Impairment of Long-Lived Assets held for sale				$ 1,135
Long-term Line of Credit			$ 40,000	40,000
Jones Act Tug-Barge [Member]
Impairment of Long-Lived Assets held for sale			1,100	$ 1,100
DVB Bank SE [Member]
Debt instrument amendment description				significant amendments included (i) requiring us to apply the proceeds from the sale of one of our PCTCs to pay down 100% of the debt owned under one facility of approximately $30.2 million and $912,000 of the debt owed under the other facility, (ii) pledging under certain circumstances 65% of our shares of our wholly-owned Singapore subsidiaries to DVB Bank SE, (iii) increasing the interest rate by 2%, (iv) increasing by approximately $222,000 our quarterly principal payments and (v) specifying various dates (ranging from December 2015 through March 2016) by which our sale of non-core assets must be completed and at specified amounts.
Number of loan facilities | loan				2
Senior Secured Credit Facility [Member] | Regions Bank [Member]
Credit facility maturity date				Sep. 24, 2018
Line of credit facility borrowing capacity			85,000	$ 85,000
Long-term Line of Credit			31,000	31,000
Standby Letters of Credit [Member]
Long-term Line of Credit			20,000	20,000
Standby Letters of Credit [Member] | Regions Bank [Member]
Line of credit facility borrowing capacity			$ 20,000	$ 20,000
ING Bank [Member]
Debt instrument amendment description				significant amendments included (i) increasing by approximately $625,000 our quarterly principal payments, (ii) increasing our interest rate margin by approximately 2% per annum, (iii) modifying the manner in which we will be required to pay down debt owed under the facility upon the sale of assets comprising collateral under the facility, including requiring any excess proceeds to be applied to pay off the other tranches at the discretion of the facility's agent, (iv) providing credit enhancements of equal value to those afforded by us to our other creditors, (v) prohibiting the payment of common stock dividends, (vi) prohibiting the payment of preferred stock dividends without the written consent from the lender, (vii) requiring the preparation of a financial plan acceptable to the facility agent in its sole discretion, and (viii) specifying various amounts and dates in December 2015 by which our sale of non-core assets must be completed.
Credit Facility Amendment [Member] | Senior Secured Credit Facility [Member] | Regions Bank [Member]
Credit facility maturity date				Jul. 20, 2017
Debt instrument amendment description				amendments to our Senior Credit Facility with Regions Bank included (i) accelerating the facility's maturity date from September 24, 2018 to July 20, 2017, (ii) reducing the Letter of Credit Sublimit from $20 million to $7.2 million initially and to lower amounts at future dates, (iii) prohibiting us from issuing new letters of credit without the lenders' consent, (iv) reducing the Aggregate Revolving Commitment by $1.8 million, (v) increasing the applicable margins for all Loans, Letter of Credit Fees and Commitment Fees set to 9.25% from the effective date of the amendment through June 30, 2016, and 10.0% from July 1, 2016 through the maturity date, (vi) increasing our scheduled payments for the next twelve months by $3.0 million and mandating certain specified mandatory prepayments, (vii) prohibiting us from paying common stock dividends unless we have at least $30.0 million of liquidity (as defined in the credit facility) after making the payment, (viii) prohibiting us from paying preferred stock dividends prior to January 29, 2016 or paying preferred stock dividends thereafter unless various financial conditions are met, (ix) prohibiting us from making any further payments to construct our New Orleans headquarters, except to the extent financed by the general contractor, and (x) amending certain of our financial covenants, effective as of June 30, 2016, and amending certain of our other loan covenants to further restrict our operations, effective immediately.
Subsequent Event [Member]
Number of core segments approved for restructuring | segment					3
Subsequent Event [Member] | Jones Act Tug-Barge [Member]
Number of core segments approved for restructuring | item					1
Subsequent Event [Member] | International Flag PCTC [Member]
Number of core segments approved for restructuring | item					1
Number of held for sale assets being actively marketed | item	1
Subsequent Event [Member] | Standby Letters of Credit [Member] | Regions Bank [Member]
Line of credit facility borrowing capacity		$ 7,200
Subsequent Event [Member] | Credit Facility Amendment [Member] | PCTC [Member]
Number of held for sale assets being actively marketed | item		1
Subsequent Event [Member] | Credit Facility Amendment [Member] | DVB Bank SE [Member]
Percentage of debt to be paid down from proceed of asset sold		100.00%
Ownership interest in wholly-owned Singapore subsidiaries to be pledged		65.00%
Increase in quarterly principal payment amounts		$ 222
Increase in interest rate margins per annum		2.00%
Subsequent Event [Member] | Credit Facility Amendment [Member] | RBS Asset Finance [Member]
Increase in interest rate margins per annum		1.00%
Subsequent Event [Member] | Credit Facility Amendment [Member] | Senior Secured Credit Facility [Member] | Regions Bank [Member]
Reduce aggregate revolving commitment		$ 1,800
Long term debt covenant minimum liquidity amount		30,000
Subsequent Event [Member] | Credit Facility Amendment [Member] | Loan Facility A [Member] | DVB Bank SE [Member]
Repayments of debt		30,200
Subsequent Event [Member] | Credit Facility Amendment [Member] | Loan Facility B [Member] | DVB Bank SE [Member]
Repayments of debt		912
Subsequent Event [Member] | Credit Facility Amendment [Member] | ING Bank [Member]
Increase in quarterly principal payment amounts		$ 625
Increase in interest rate margins per annum		2.00%
Subsequent Event [Member] | Credit Facility Amendment [Member] | Maximum [Member] | RBS Asset Finance [Member]
Loan-to-value ratio		75.00%
Subsequent Event [Member] | Memorandum of Agreement to Sell [Member] | International Flag PCTC [Member]
Net proceeds from sale of vessels	$ 15,100
Loss on sale of vessels	16,700
Repayments of debt	$ 31,300
Subsequent Event [Member] | Fourth Quarter 2015 [Member] | Minimum [Member]
Impairment of Long-Lived Assets held for sale		$ 85,000
Subsequent Event [Member] | Fourth Quarter 2015 [Member] | Maximum [Member]
Impairment of Long-Lived Assets held for sale		$ 95,000
Subsequent Event [Member] | November 13,2015 through June 30, 2016 [Member] | Credit Facility Amendment [Member] | Standby Letters of Credit [Member] | Regions Bank [Member]
Line of credit facility commitment fees		9.25%
Subsequent Event [Member] | July 1, 2016 through July 20, 2017 [Member] | Credit Facility Amendment [Member] | Standby Letters of Credit [Member] | Regions Bank [Member]
Line of credit facility commitment fees		10.00%
Subsequent Event [Member] | Next Twelve Months [Member] | Senior Secured Credit Facility [Member] | Regions Bank [Member]
Increase in scheduled payments		$ 3,000