Fair Value Measurements (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012		Dec. 31, 2011
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	$ 13,382		$ 12,983
Derivative assets	172
Derivative liabilities	(8,467)
Vessels	37,070	[1]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Rail-Ferry Vessels	37,070	[1]
Carrying Amount [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Vessels	32,500
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Rail-Ferry Vessels	32,500
Level 1 Inputs [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	13,382
Derivative assets	0
Derivative liabilities	0
Vessels	0	[1]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Rail-Ferry Vessels	0	[1]
Level 2 Inputs [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	0
Derivative assets	172
Derivative liabilities	(8,467)
Vessels	37,070	[1]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Rail-Ferry Vessels	37,070	[1]
Level 3 Inputs [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	0
Derivative assets	0
Derivative liabilities	0
Vessels	0	[1]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Rail-Ferry Vessels	$ 0	[1]

[1] Represents the appraised fair value of our Rail-Ferry vessels after the impairment charge taken in the third quarter of 2010. The valuation technique used was a weighted average of the cost, comparable sales and income approaches. The carrying value of the Rail-Ferry vessels ($32.5 million as of September 30, 2012) no longer equals the fair value.