Property, Plant and Equipment (Details Textual) (USD $) In Millions, unless otherwise specified	3 Months Ended	12 Months Ended
Mar. 31, 2012	Mar. 31, 2011	Dec. 31, 2011
Property, Plant and Equipment (Textual) [Abstract]
Depreciation expense on property, plant and equipment	$ 5.5	$ 4.9	$ 20.4
Depreciation expense on railcar assets leased to others	$ 3.9	$ 3.3	$ 13.8

The reporting period depreciation, depletion and amortization expense on long-lived, physical assets used in the normal conduct of business and not intended for resale. Examples include land, buildings, and production equipment.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher AICPA

-Name Accounting Principles Board Opinion (APB)

-Number 12

-Paragraph 5

Name:	us-gaap_AccumulatedDepreciationDepletionAndAmortizationExpensePropertyPlantAndEquipmentCurrentCharge
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration