Investment Securities - Available for Sale (Details 3) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Unrealized losses and fair value of available for sale securities , by investment category and time length
Unrealized losses on available for sale securities, less than 12 months	$ (512)	$ (2,133)
Unrealized losses on available for sale securities, 12 months or more	(155)	(1,530)
Total unrealized losses on available for sale securities	(667)	(3,663)
Fair value of unrealized losses on available for sale securities, less than 12 months	128,384	237,411
Fair value of unrealized losses on available for sale securities, 12 months or more	2,607	176,979
Total fair value of unrealized losses on available for sale securities	130,991	414,390
Obligations of state and political subdivisions (municipal securities) [Member]
Unrealized losses and fair value of available for sale securities , by investment category and time length
Unrealized losses on available for sale securities, less than 12 months	(91)	(10)
Unrealized losses on available for sale securities, 12 months or more	(14)	(18)
Total unrealized losses on available for sale securities	(105)	(28)
Fair value of unrealized losses on available for sale securities, less than 12 months	11,699	971
Fair value of unrealized losses on available for sale securities, 12 months or more	457	348
Total fair value of unrealized losses on available for sale securities	12,156	1,319
Number of available for sale securities in a continuous unrealized loss position less than twelve months	31
Number of available for sale securities in a continuous unrealized loss position for twelve months or more	2
Residential mortgage-related securities [Member]
Unrealized losses and fair value of available for sale securities , by investment category and time length
Unrealized losses on available for sale securities, less than 12 months	(421)	(1,443)
Unrealized losses on available for sale securities, 12 months or more	(64)	(20)
Total unrealized losses on available for sale securities	(485)	(1,463)
Fair value of unrealized losses on available for sale securities, less than 12 months	116,685	186,954
Fair value of unrealized losses on available for sale securities, 12 months or more	2,040	1,469
Total fair value of unrealized losses on available for sale securities	118,725	188,423
Number of available for sale securities in a continuous unrealized loss position less than twelve months	6
Number of available for sale securities in a continuous unrealized loss position for twelve months or more	5
Asset-backed Securities [Member]
Unrealized losses and fair value of available for sale securities , by investment category and time length
Unrealized losses on available for sale securities, less than 12 months	0	(9)
Unrealized losses on available for sale securities, 12 months or more	0	(698)
Total unrealized losses on available for sale securities	0	(707)
Fair value of unrealized losses on available for sale securities, less than 12 months	0	4,091
Fair value of unrealized losses on available for sale securities, 12 months or more	0	174,640
Total fair value of unrealized losses on available for sale securities	0	178,731
Number of available for sale securities in a continuous unrealized loss position less than twelve months	0
Number of available for sale securities in a continuous unrealized loss position for twelve months or more	0
Other Debt And Other Equity Securities [Member]
Unrealized losses and fair value of available for sale securities , by investment category and time length
Unrealized losses on available for sale securities, less than 12 months	0	(671)
Unrealized losses on available for sale securities, 12 months or more	(77)	(794)
Total unrealized losses on available for sale securities	(77)	(1,465)
Fair value of unrealized losses on available for sale securities, less than 12 months	0	45,395
Fair value of unrealized losses on available for sale securities, 12 months or more	110	522
Total fair value of unrealized losses on available for sale securities	$ 110	$ 45,917
Number of available for sale securities in a continuous unrealized loss position less than twelve months	0
Number of available for sale securities in a continuous unrealized loss position for twelve months or more	1

Number of available for sale securities in a continuous unrealized loss position less than twelve months

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Number of available for sale securities in a continuous unrealized loss position twelve months or longer aggregate losses.

+ References

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Amount of the excess of amortized cost basis over fair value of securities that have been in a loss position for twelve months or longer for securities which are categorized neither as held-to-maturity nor trading securities.

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This item represents the aggregate fair value of investments in debt and equity securities in an unrealized loss position which are categorized neither as held-to-maturity nor trading securities.

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