Fair Value Measurements (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	$ 13,111
Derivative assets	42
Derivative liabilities	(8,189)
Vessels	37,070	[1]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Rail-Ferry Vessels	37,070	[1]
Appraised Fair Value [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Vessels	37,070
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Rail-Ferry Vessels	37,070
Carrying Amount [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Vessels	33,200
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Rail-Ferry Vessels	33,200
Level 1 Inputs [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	13,111
Derivative assets	0
Derivative liabilities	0
Vessels	0
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Rail-Ferry Vessels	0
Level 2 Inputs [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	0
Derivative assets	42
Derivative liabilities	(8,189)
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
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Rail-Ferry Vessels	$ 0

[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 ($33.2 million as of June 30, 2012) no longer equals the fair value.