Amount of direct costs of the business combination including legal, accounting, and other costs incurred to consummate the business acquisition.

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 141

-Paragraph 51

-Subparagraph d

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 141

-Paragraph 24

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Name:	us-gaap_BusinessAcquisitionCostOfAcquiredEntityTransactionCosts
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Changes in Operations (Details2) (USD $) In Millions, unless otherwise specified	Dec. 31, 2011 AZER [Member]	Sep. 01, 2011 AZER [Member] employees locomotives rail_lines track_miles	May 01, 2012 CCH [Member] track_miles	Jan. 02, 2012 HAL [Member] track_miles
Business Acquisition [Line Items]
Track miles leased			26	56
Cost of acquired entity		$ 89.5
Working capital adjustment to purchase price	0.8	(0.6)
Acquisition costs		$ 0.6
Number of employees acquired		43
Number of locomotives acquired		10
Number of rail lines acquired		2
Track miles acquired		200
Trackage rights miles acquired		52