Annual coal reserve payments to be made by Company.

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- Definition

Business acquisition cost of acquired entity cash purchase price per share.

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- Definition

Business acquisition cost of acquired entity maximum cash purchase price per share.

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- Definition

Business acquisition percentage of voting interests acquired by other company.

+ Details

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- Definition

Business combination merged company voting interest in acquiree company.

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- Definition

Conditions of any resulting offers to shareholders.

+ Details

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- Definition

First coal reserve payment made by the Company.

+ Details

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- Definition

Maximum Final Dividend per share entitled to be retained by acquiree company shareholders.

+ Details

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- Definition

Number of tons of coal in which the Company was named the winning bidder.

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- Definition

Subsequent events.

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- Definition

The acquisition-date fair value of the equity interests of the acquirer, including the number of instruments or interests issued or issuable in consideration for the business combination.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 141R
-Paragraph 68
-Subparagraph f(4)
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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 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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Emerging Issues Task Force (EITF)
-Number 88-16
-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 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 141R
-Paragraph 39
-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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- Definition

Percentage of voting equity interests acquired in the business combination.

+ References

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Subsequent Events (Details)	1 Months Ended	6 Months Ended
Subsequent Events (Details)	Jul. 31, 2011 USD ($) Tons	Jun. 30, 2011 AUD	Aug. 01, 2011 USD ($)	Aug. 01, 2011 AUD
Subsequent Events (Textuals) [Abstract]
Cash price per share for proposed acquisition				15.50
Implied value for the equity of proposed acquired company			$ 5,200,000,000	4,700,000,000
Ownership percentage of the Company in the newly formed company			60.00%	60.00%
Ownership percentage of the joint owner in the newly formed company			40.00%	40.00%
Conditions of any resulting offers to shareholders		subject to a number of conditions including minimum 50.01% acceptances, approval by Australia’s Foreign Investment Review Board, other regulatory approvals and other standard conditions
Relevant interest percentage in proposed acquisition by newly formed company			16.10%	16.10%
Maximum dividend declared per share AUD ($) to be retained by shareholders of proposed acquisition company		0.16
Implied value per share of proposed acquired company				15.66
Number of tons of coal in the Powder River Basin of Wyoming in which the Company was named the winning bidder	220,000,000
First coal reserve payment made by the Company	42,100,000
Annual coal reserve payments to be made by the Company in July of each of the next four years	$ 42,100,000