Portfolio Loans Not Covered by Loss Share ("Non-covered") - Summary of Recorded Investment by Risk Category of Non-covered Loans by Portfolio Class and Category (Details) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2012	Dec. 31, 2011
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Credit Quality, Time Period Expected to Return to Perform	12 months
Total	$ 1,987,166	$ 1,897,074
Non-Covered Loans
Financing Receivable, Recorded Investment [Line Items]
Portfolio Loans	1,987,144	1,897,412
Total	1,987,166	1,897,074
Non-Covered Loans | Pass (1-6)
Financing Receivable, Recorded Investment [Line Items]
Total	1,735,221	1,616,434
Non-Covered Loans | Watch (7)
Financing Receivable, Recorded Investment [Line Items]
Total	142,963	178,653
Non-Covered Loans | Substandard (8)
Financing Receivable, Recorded Investment [Line Items]
Total	108,130	96,228
Non-Covered Loans | Doubtful (9)
Financing Receivable, Recorded Investment [Line Items]
Total	852	5,759
Non-Covered Loans | Commercial & Industrial
Financing Receivable, Recorded Investment [Line Items]
Portfolio Loans	880,394	763,202
Non-Covered Loans | Commercial & Industrial | Pass (1-6)
Financing Receivable, Recorded Investment [Line Items]
Portfolio Loans	824,351	683,239
Non-Covered Loans | Commercial & Industrial | Watch (7)
Financing Receivable, Recorded Investment [Line Items]
Portfolio Loans	37,878	50,197
Non-Covered Loans | Commercial & Industrial | Substandard (8)
Financing Receivable, Recorded Investment [Line Items]
Portfolio Loans	18,165	27,229
Non-Covered Loans | Commercial & Industrial | Doubtful (9)
Financing Receivable, Recorded Investment [Line Items]
Portfolio Loans	0	2,537
Non-Covered Loans | Real Estate
Financing Receivable, Recorded Investment [Line Items]
Portfolio Loans	1,095,056	1,122,751
Non-Covered Loans | Real Estate | Commercial - Owner Occupied
Financing Receivable, Recorded Investment [Line Items]
Portfolio Loans	325,379	334,416
Non-Covered Loans | Real Estate | Commercial - Owner Occupied | Pass (1-6)
Financing Receivable, Recorded Investment [Line Items]
Portfolio Loans	279,806	276,802
Non-Covered Loans | Real Estate | Commercial - Owner Occupied | Watch (7)
Financing Receivable, Recorded Investment [Line Items]
Portfolio Loans	30,850	40,207
Non-Covered Loans | Real Estate | Commercial - Owner Occupied | Substandard (8)
Financing Receivable, Recorded Investment [Line Items]
Portfolio Loans	14,379	16,225
Non-Covered Loans | Real Estate | Commercial - Owner Occupied | Doubtful (9)
Financing Receivable, Recorded Investment [Line Items]
Portfolio Loans	344	1,182
Non-Covered Loans | Real Estate | Commercial - Investor Owned
Financing Receivable, Recorded Investment [Line Items]
Portfolio Loans	476,501	477,154
Non-Covered Loans | Real Estate | Commercial - Investor Owned | Pass (1-6)
Financing Receivable, Recorded Investment [Line Items]
Portfolio Loans	387,509	405,686
Non-Covered Loans | Real Estate | Commercial - Investor Owned | Watch (7)
Financing Receivable, Recorded Investment [Line Items]
Portfolio Loans	54,161	56,370
Non-Covered Loans | Real Estate | Commercial - Investor Owned | Substandard (8)
Financing Receivable, Recorded Investment [Line Items]
Portfolio Loans	34,831	14,894
Non-Covered Loans | Real Estate | Commercial - Investor Owned | Doubtful (9)
Financing Receivable, Recorded Investment [Line Items]
Portfolio Loans	0	204
Non-Covered Loans | Real Estate | Construction and Land Development
Financing Receivable, Recorded Investment [Line Items]
Portfolio Loans	146,236	140,147
Non-Covered Loans | Real Estate | Construction and Land Development | Pass (1-6)
Financing Receivable, Recorded Investment [Line Items]
Portfolio Loans	101,683	91,286
Non-Covered Loans | Real Estate | Construction and Land Development | Watch (7)
Financing Receivable, Recorded Investment [Line Items]
Portfolio Loans	15,101	27,056
Non-Covered Loans | Real Estate | Construction and Land Development | Substandard (8)
Financing Receivable, Recorded Investment [Line Items]
Portfolio Loans	28,944	21,461
Non-Covered Loans | Real Estate | Construction and Land Development | Doubtful (9)
Financing Receivable, Recorded Investment [Line Items]
Portfolio Loans	508	344
Non-Covered Loans | Real Estate | Residential
Financing Receivable, Recorded Investment [Line Items]
Portfolio Loans	146,940	171,034
Non-Covered Loans | Real Estate | Residential | Pass (1-6)
Financing Receivable, Recorded Investment [Line Items]
Portfolio Loans	130,212	148,309
Non-Covered Loans | Real Estate | Residential | Watch (7)
Financing Receivable, Recorded Investment [Line Items]
Portfolio Loans	4,967	4,814
Non-Covered Loans | Real Estate | Residential | Substandard (8)
Financing Receivable, Recorded Investment [Line Items]
Portfolio Loans	11,761	16,419
Non-Covered Loans | Real Estate | Residential | Doubtful (9)
Financing Receivable, Recorded Investment [Line Items]
Portfolio Loans	0	1,492
Non-Covered Loans | Consumer & Other
Financing Receivable, Recorded Investment [Line Items]
Portfolio Loans	11,694	11,459
Total	11,716	11,121
Non-Covered Loans | Consumer & Other | Pass (1-6)
Financing Receivable, Recorded Investment [Line Items]
Total	11,660	11,112
Non-Covered Loans | Consumer & Other | Watch (7)
Financing Receivable, Recorded Investment [Line Items]
Total	6	9
Non-Covered Loans | Consumer & Other | Substandard (8)
Financing Receivable, Recorded Investment [Line Items]
Total	50	0
Non-Covered Loans | Consumer & Other | Doubtful (9)
Financing Receivable, Recorded Investment [Line Items]
Total	$ 0	$ 0