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	Jun. 30, 2011	Dec. 31, 2010
Trading securities owned	$ 603,964	$ 444,170
Trading securities pledged	300,249	272,172
U.S. Government Agency Securities [Member]
Trading securities owned	141,510	86,882
Trading securities sold, but not yet purchased	6,380	664
U.S. Government Securities [Member]
Trading securities owned	25,975	9,038
Trading securities sold, but not yet purchased	106,666	131,561
Corporate Fixed Income Securities [Member]
Trading securities owned	290,673	221,145
Fixed income securities	156,969	61,026
Corporate Equity Securities [Member]
Equity securities	40,789	46,877
Equity securities	21,187	6,800
State and Municipal Securities [Member]
Trading securities owned	105,017	80,228
State and municipal securities	$ 263	$ 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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-Publisher FASB
-Name Accounting Standards Codification
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-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
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+ Details

- 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
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Trading Securities
-URI http://asc.fasb.org/extlink&oid=6526789

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-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
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-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 Statement of Financial Accounting Standard (FAS)
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-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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+ Details

- Definition

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

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Trading Securities
-URI http://asc.fasb.org/extlink&oid=6526789

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-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
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+ Details