Investment Securities Summary of Amortized Cost and Fair Values of Corporate Debt Securities (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Debt Securities	$ 2,672,366
Corporate Debt Securities Issued by Financial Institutions [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Debt Securities, Amortized Cost Basis	107,589	130,319
Available-for-sale Securities, Debt Securities	103,604	120,770
Single-issuer Trust Preferred Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Debt Securities, Amortized Cost Basis	57,726	83,899
Available-for-sale Securities, Debt Securities	50,426	74,365
Subordinated Debt [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Debt Securities, Amortized Cost Basis	44,262	40,184
Available-for-sale Securities, Debt Securities	48,037	41,296
Pooled Trust Preferred Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Debt Securities, Amortized Cost Basis	5,601	6,236
Available-for-sale Securities, Debt Securities	5,141	5,109
Other Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Debt Securities, Amortized Cost Basis	2,522	2,536
Available-for-sale Securities, Debt Securities	2,522	2,536
Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Debt Securities, Amortized Cost Basis	110,111	132,855
Available-for-sale Securities, Debt Securities	$ 106,126	$ 123,306

For an unclassified balance sheet, total of debt securities categorized neither as held-to-maturity nor trading.

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Reference 4: http://www.xbrl.org/2003/role/presentationRef

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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