Related Party Transactions (Details) (Series A Convertible Perpetual Preferred Stock [Member], USD $) In Millions, except Share data, unless otherwise specified	0 Months Ended	6 Months Ended	12 Months Ended
May 25, 2007	Jul. 31, 2011	Jan. 31, 2011	May 31, 2007
Series A Convertible Perpetual Preferred Stock [Member]
Aggregate number of share purchase for cash	293,000
Aggregate purchase price of preferred stock	$ 293.0
Cumulative, undeclared dividends on the preferred stock		52.3	45.7
Liquidation preference of the preferred stock		$ 345.3	$ 338.7
Initial conversion rate for each share of preferred stock shares in to common stock				30.6185
Number of preferred stock could be converted into common stock		10,600,000	10,400,000

Number of shares issued for each share of convertible preferred stock that is converted.

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- Definition

Liquidation preference of the preferred stock.

+ Details

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- Definition

Number of preferred stock could be converted into common stock.

+ Details

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- Definition

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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

+ Details

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- Definition

Number of shares of equity interests issued or issuable to acquire entity.

+ References

+ Details

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- Definition

Aggregate amount of cumulative preferred dividends in arrears.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 129
-Paragraph 7
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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 Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 5
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21488-112644

+ Details

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