Trading Securities Owned and Trading Securities Sold, But Not Yet Purchased (Components of Trading Securities Owned and Trading Securities Sold, But Not Yet Purchased) (Details) (USD $) In Thousands	Sep. 30, 2011	Dec. 31, 2010
Trading securities owned	$ 526,444	$ 444,170
U.S. Government Agency Securities [Member]
Trading securities owned	71,333	86,882
Trading securities sold, but not yet purchased	0	664
U.S. Government Securities [Member]
Trading securities owned	12,202	9,038
Trading securities sold, but not yet purchased	109,568	131,561
Corporate Fixed Income Securities [Member]
Trading securities owned	264,623	221,145
Fixed income securities	129,226	61,026
Corporate Equity Securities [Member]
Equity securities	40,886	46,877
Equity securities	33,071	6,800
State and Municipal Securities [Member]
Trading securities owned	137,400	80,228
State and municipal securities	$ 325	$ 89

The total of 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) 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.

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- Definition

Debt securities 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) or for debt 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

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

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Total common and preferred stock (which is not mandatorily redeemable, redeemable at the option of the holder, or in any other way classified as liability) equity securities 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) or for 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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