Shareholders' Equity (Narrative) (Details) (USD $)	1 Months Ended	9 Months Ended
May 31, 2010	Sep. 30, 2010
Shareholders' Equity [Abstract]
Sale of repurchased common stock	4,300,000
Repurchased common stock price per share	$ 35.00
Proceeds from issuance of common stock	$ 143,300,000	$ 143,325,000
Reduction to retained earnings	42,800,000
Historical cost of stock issued	$ 186,100,000

Historical cost of stock issued.

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- Definition

The cash inflow from the additional capital contribution to the entity.

+ References

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-Name Accounting Standards Codification

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-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 95

-Paragraph 18

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-Publisher FASB

-Name Accounting Standards Codification

-Glossary Financing Activities

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- Definition

The dollar amount received by subsidiary or equity investee for each share of common stock issued or sold in the stock transaction.

+ References

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

-Publisher SEC

-Name Staff Accounting Bulletin (SAB)

-Number Topic 5

-Section H

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- Definition

Number of shares issued during the period as a result of an employee stock purchase plan.

+ References

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-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 29, 30

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-Publisher AICPA

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-Number 12

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-Name Regulation S-X (SX)

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- Definition

Equity impact of the value of stock that has been repurchased and retired during the period. The excess of the purchase price over par value can be charged against retained earnings (once the excess is fully allocated to additional paid in capital).

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

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