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Significant Acquisitions (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2012 T	Sep. 30, 2009 T
Acquisitions (Textual) [Abstract]
Amount paid at closing	$ 40.0
Sugar Camp [Member]
Acquisitions (Textual) [Abstract]
Purchase price	58.9
Business Acquisition Purchase Price Allocation Rail Load out Assets Acquired	50.0
Contractual overriding royalty interest	8.9
Colt [Member]
Acquisitions (Textual) [Abstract]
Purchase price		255.0
Coal reserve agreed to acquire under partnership agreement	118,100,000	200,000,000
Amount paid at closing	215.0
Transportation Equipment [Member] | Sugar Camp [Member]
Acquisitions (Textual) [Abstract]
Business Acquisition Purchase Price Allocation Rail Load out Assets Acquired	10.1
Intangible Asset [Member] | Sugar Camp [Member]
Acquisitions (Textual) [Abstract]
Business Acquisition Purchase Price Allocation Rail Load out Assets Acquired	$ 39.9

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Business acquisition cost of acquired entity amount paid at closing.

+ References

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Business acquisition purchase price allocation contractual overriding royalty interest acquired.

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Business acquisition purchase price allocation rail loadout assets acquired.

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Coal reserve agreed to acquire under partnership agreement.

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The total cost of the acquired entity including the cash paid to shareholders of acquired entities, fair value of debt and equity securities issued to shareholders of acquired entities, the fair value of the liabilities assumed, and direct costs of the acquisition.

+ References

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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.

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