Subsequent Event (Narrative) (Details) - USD ($) $ in Millions					3 Months Ended		12 Months Ended
	Apr. 19, 2016	Apr. 13, 2016	Apr. 07, 2016	Apr. 06, 2016	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015
Repayments of debt from sale proceeds						$ 13.5
Subsequent Event [Member]
Increase in interest rate margins				50.00%
Subsequent Event [Member] | Jones Act Tug-Barge [Member]
Net proceeds from sale of vessels		$ 0.4
Repayment of debt		$ 0.7
Subsequent Event [Member] | Jones Act [Member]
Repayments of debt from sale proceeds				$ 0.7
Subsequent Event [Member] | Sale Of New Orleans Office Building [Member]
Payment of amount owed to construction company			$ 6.2
9.50% Series A Preferred Stock [Member]
Preferred stock, dividend rate					9.50%		9.50%
9.50% Series A Preferred Stock [Member] | Minimum [Member]
Preferred stock, dividend rate	11.50%
9.50% Series A Preferred Stock [Member] | Subsequent Event [Member] | Maximum [Member]
Preferred stock, dividend rate	13.50%
9.00% Series B Preferred Stock [Member]
Preferred stock, dividend rate					9.00%		9.00%
9.00% Series B Preferred Stock [Member] | Minimum [Member]
Preferred stock, dividend rate	11.00%
9.00% Series B Preferred Stock [Member] | Subsequent Event [Member] | Maximum [Member]
Preferred stock, dividend rate	13.00%