Investments Narrative (Details) (USD $)	9 Months Ended
Sep. 30, 2011	Sep. 30, 2010	Dec. 31, 2010
Schedule of Investments [Line Items]
Investments in fluctuating-value mutual funds	$ 153,600,000		$ 105,700,000
Trading securities	35,800,000		29,200,000
Payments to Acquire Available-for-sale Securities	72,108,000	58,202,000
Available-for-sale Securities, Fair Value Disclosure	107,200,000
Fixed-Income Mutual Funds [Member]
Schedule of Investments [Line Items]
Payments to Acquire Available-for-sale Securities	60,000,000
Available-for-sale Securities, Gross Unrealized Losses	1,565,000		136,000
Total Fluctuating-Value Mutual Funds [Member]
Schedule of Investments [Line Items]
Available-for-sale Securities, Gross Unrealized Losses	$ 5,138,000		$ 160,000

The cash outflow to acquire debt and equity securities not classified as either held-to-maturity securities or trading securities which would be classified as available-for-sale securities and reported at fair value, with unrealized gains and losses excluded from earnings and reported in a separate component of shareholders' equity.

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

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-Name Accounting Standards Codification

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+ Details

- Definition

Financial instruments that are bought and held principally for the purpose of selling them in the near term (thus held for only a short period of time, usually less than one year or the normal operating cycle, whichever is longer) or for debt and equity securities formerly categorized as available-for-sale or held-to-maturity which the entity held as of the date it opted to account for such securities at fair value. An enterprise may also categorize such a security as trading without the intent to sell it in the near term assuming the decision to categorize the security as trading occurred at acquisition.

+ References

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+ Details