Portfolio Loans Not Covered by Loss Share ("Non-covered") - Summary of Recorded Investment by Category of Non-covered Loans Restructured (Details) (USD $)	3 Months Ended	9 Months Ended
	Sep. 30, 2012 loan	Sep. 30, 2012 loan
Financing Receivable, Modifications [Line Items]
Financing Receivable Modifications Reserve	$ 791,000,000	$ 791,000,000
Non-Covered Loans
Financing Receivable, Modifications [Line Items]
Number of Loans	2	4
Pre-Modification Outstanding Recorded Balance	357,000	6,244,000
Post-Modification Outstanding Recorded Balance	207,000	4,712,000
Non-Covered Loans | Commercial & Industrial
Financing Receivable, Modifications [Line Items]
Number of Loans	1	0
Pre-Modification Outstanding Recorded Balance	150,000	0
Post-Modification Outstanding Recorded Balance	0	0
Non-Covered Loans | Real Estate | Commercial - Owner Occupied
Financing Receivable, Modifications [Line Items]
Number of Loans	1	1
Pre-Modification Outstanding Recorded Balance	207,000	207,000
Post-Modification Outstanding Recorded Balance	207,000	207,000
Non-Covered Loans | Real Estate | Commercial - Investor Owned
Financing Receivable, Modifications [Line Items]
Number of Loans	0	0
Pre-Modification Outstanding Recorded Balance	0	0
Post-Modification Outstanding Recorded Balance	0	0
Non-Covered Loans | Real Estate | Construction and Land Development
Financing Receivable, Modifications [Line Items]
Number of Loans	0	2
Pre-Modification Outstanding Recorded Balance	0	4,341,000
Post-Modification Outstanding Recorded Balance	0	2,809,000
Non-Covered Loans | Real Estate | Residential
Financing Receivable, Modifications [Line Items]
Number of Loans	0	1
Pre-Modification Outstanding Recorded Balance	0	1,696,000
Post-Modification Outstanding Recorded Balance	0	1,696,000
Non-Covered Loans | Consumer & Other
Financing Receivable, Modifications [Line Items]
Number of Loans	0	0
Pre-Modification Outstanding Recorded Balance	0	0
Post-Modification Outstanding Recorded Balance	$ 0	$ 0