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	6 Months Ended
	Jun. 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	$ 1,948,994	$ 1,897,074
Non-Covered Loans
Financing Receivable, Recorded Investment [Line Items]
Portfolio Loans	1,949,270	1,897,412
Total	1,948,994	1,897,074
Non-Covered Loans | Pass (1-6)
Financing Receivable, Recorded Investment [Line Items]
Total	1,675,068	1,616,434
Non-Covered Loans | Watch (7)
Financing Receivable, Recorded Investment [Line Items]
Total	159,301	178,653
Non-Covered Loans | Substandard (8)
Financing Receivable, Recorded Investment [Line Items]
Total	113,592	96,228
Non-Covered Loans | Doubtful (9)
Financing Receivable, Recorded Investment [Line Items]
Total	1,033	5,759
Non-Covered Loans | Commercial & Industrial
Financing Receivable, Recorded Investment [Line Items]
Portfolio Loans	841,383	763,202
Non-Covered Loans | Commercial & Industrial | Pass (1-6)
Financing Receivable, Recorded Investment [Line Items]
Portfolio Loans	768,797	683,239
Non-Covered Loans | Commercial & Industrial | Watch (7)
Financing Receivable, Recorded Investment [Line Items]
Portfolio Loans	52,630	50,197
Non-Covered Loans | Commercial & Industrial | Substandard (8)
Financing Receivable, Recorded Investment [Line Items]
Portfolio Loans	19,956	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	1,093,867	1,122,751
Non-Covered Loans | Real Estate | Commercial - Owner Occupied
Financing Receivable, Recorded Investment [Line Items]
Portfolio Loans	322,491	334,416
Non-Covered Loans | Real Estate | Commercial - Owner Occupied | Pass (1-6)
Financing Receivable, Recorded Investment [Line Items]
Portfolio Loans	273,950	276,802
Non-Covered Loans | Real Estate | Commercial - Owner Occupied | Watch (7)
Financing Receivable, Recorded Investment [Line Items]
Portfolio Loans	33,381	40,207
Non-Covered Loans | Real Estate | Commercial - Owner Occupied | Substandard (8)
Financing Receivable, Recorded Investment [Line Items]
Portfolio Loans	14,816	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	479,492	477,154
Non-Covered Loans | Real Estate | Commercial - Investor Owned | Pass (1-6)
Financing Receivable, Recorded Investment [Line Items]
Portfolio Loans	393,624	405,686
Non-Covered Loans | Real Estate | Commercial - Investor Owned | Watch (7)
Financing Receivable, Recorded Investment [Line Items]
Portfolio Loans	50,330	56,370
Non-Covered Loans | Real Estate | Commercial - Investor Owned | Substandard (8)
Financing Receivable, Recorded Investment [Line Items]
Portfolio Loans	35,538	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	142,474	140,147
Non-Covered Loans | Real Estate | Construction and Land Development | Pass (1-6)
Financing Receivable, Recorded Investment [Line Items]
Portfolio Loans	97,463	91,286
Non-Covered Loans | Real Estate | Construction and Land Development | Watch (7)
Financing Receivable, Recorded Investment [Line Items]
Portfolio Loans	17,830	27,056
Non-Covered Loans | Real Estate | Construction and Land Development | Substandard (8)
Financing Receivable, Recorded Investment [Line Items]
Portfolio Loans	26,492	21,461
Non-Covered Loans | Real Estate | Construction and Land Development | Doubtful (9)
Financing Receivable, Recorded Investment [Line Items]
Portfolio Loans	689	344
Non-Covered Loans | Real Estate | Residential
Financing Receivable, Recorded Investment [Line Items]
Portfolio Loans	149,410	171,034
Non-Covered Loans | Real Estate | Residential | Pass (1-6)
Financing Receivable, Recorded Investment [Line Items]
Portfolio Loans	127,496	148,309
Non-Covered Loans | Real Estate | Residential | Watch (7)
Financing Receivable, Recorded Investment [Line Items]
Portfolio Loans	5,124	4,814
Non-Covered Loans | Real Estate | Residential | Substandard (8)
Financing Receivable, Recorded Investment [Line Items]
Portfolio Loans	16,790	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	14,020	11,459
Total	13,744	11,121
Non-Covered Loans | Consumer & Other | Pass (1-6)
Financing Receivable, Recorded Investment [Line Items]
Total	13,738	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	0	0
Non-Covered Loans | Consumer & Other | Doubtful (9)
Financing Receivable, Recorded Investment [Line Items]
Total	$ 0	$ 0