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, 2013	Dec. 31, 2012
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Credit Quality, Time Period Expected to Return to Perform	12 months
Total	$ 2,110,825	$ 2,106,039
Non-Covered Loans
Financing Receivable, Recorded Investment [Line Items]
Portfolio Loans	2,109,943	2,106,028
Total	2,110,825	2,106,039
Non-Covered Loans | Pass (1-6)
Financing Receivable, Recorded Investment [Line Items]
Total	1,900,106	1,865,490
Non-Covered Loans | Watch (7)
Financing Receivable, Recorded Investment [Line Items]
Total	124,508	136,036
Non-Covered Loans | Substandard (8)
Financing Receivable, Recorded Investment [Line Items]
Total	85,363	101,808
Non-Covered Loans | Doubtful (9)
Financing Receivable, Recorded Investment [Line Items]
Total	848	2,705
Non-Covered Loans | Commercial & Industrial
Financing Receivable, Recorded Investment [Line Items]
Portfolio Loans	1,007,398	962,884
Non-Covered Loans | Commercial & Industrial | Pass (1-6)
Financing Receivable, Recorded Investment [Line Items]
Portfolio Loans	948,844	912,766
Non-Covered Loans | Commercial & Industrial | Watch (7)
Financing Receivable, Recorded Investment [Line Items]
Portfolio Loans	35,321	29,524
Non-Covered Loans | Commercial & Industrial | Substandard (8)
Financing Receivable, Recorded Investment [Line Items]
Portfolio Loans	22,858	18,546
Non-Covered Loans | Commercial & Industrial | Doubtful (9)
Financing Receivable, Recorded Investment [Line Items]
Portfolio Loans	375	2,048
Non-Covered Loans | Commercial Real Estate Owner Occupied
Financing Receivable, Recorded Investment [Line Items]
Portfolio Loans	350,653	333,242
Non-Covered Loans | Commercial Real Estate Owner Occupied | Pass (1-6)
Financing Receivable, Recorded Investment [Line Items]
Portfolio Loans	315,715	290,850
Non-Covered Loans | Commercial Real Estate Owner Occupied | Watch (7)
Financing Receivable, Recorded Investment [Line Items]
Portfolio Loans	20,862	26,336
Non-Covered Loans | Commercial Real Estate Owner Occupied | Substandard (8)
Financing Receivable, Recorded Investment [Line Items]
Portfolio Loans	14,076	15,898
Non-Covered Loans | Commercial Real Estate Owner Occupied | Doubtful (9)
Financing Receivable, Recorded Investment [Line Items]
Portfolio Loans	0	158
Non-Covered Loans | Commercial Real Estate Investor Owned
Financing Receivable, Recorded Investment [Line Items]
Portfolio Loans	451,102	486,467
Non-Covered Loans | Commercial Real Estate Investor Owned | Pass (1-6)
Financing Receivable, Recorded Investment [Line Items]
Portfolio Loans	381,553	389,886
Non-Covered Loans | Commercial Real Estate Investor Owned | Watch (7)
Financing Receivable, Recorded Investment [Line Items]
Portfolio Loans	43,654	64,707
Non-Covered Loans | Commercial Real Estate Investor Owned | Substandard (8)
Financing Receivable, Recorded Investment [Line Items]
Portfolio Loans	25,895	31,874
Non-Covered Loans | Commercial Real Estate Investor Owned | Doubtful (9)
Financing Receivable, Recorded Investment [Line Items]
Portfolio Loans	0	0
Non-Covered Loans | Construction and Land Development
Financing Receivable, Recorded Investment [Line Items]
Portfolio Loans	114,608	160,911
Non-Covered Loans | Construction and Land Development | Pass (1-6)
Financing Receivable, Recorded Investment [Line Items]
Portfolio Loans	81,799	124,857
Non-Covered Loans | Construction and Land Development | Watch (7)
Financing Receivable, Recorded Investment [Line Items]
Portfolio Loans	17,385	9,543
Non-Covered Loans | Construction and Land Development | Substandard (8)
Financing Receivable, Recorded Investment [Line Items]
Portfolio Loans	14,951	26,012
Non-Covered Loans | Construction and Land Development | Doubtful (9)
Financing Receivable, Recorded Investment [Line Items]
Portfolio Loans	473	499
Non-Covered Loans | Residential Real Estate
Financing Receivable, Recorded Investment [Line Items]
Portfolio Loans	150,320	145,558
Non-Covered Loans | Residential Real Estate | Pass (1-6)
Financing Receivable, Recorded Investment [Line Items]
Portfolio Loans	135,455	130,159
Non-Covered Loans | Residential Real Estate | Watch (7)
Financing Receivable, Recorded Investment [Line Items]
Portfolio Loans	7,282	5,921
Non-Covered Loans | Residential Real Estate | Substandard (8)
Financing Receivable, Recorded Investment [Line Items]
Portfolio Loans	7,583	9,478
Non-Covered Loans | Residential Real Estate | Doubtful (9)
Financing Receivable, Recorded Investment [Line Items]
Portfolio Loans	0	0
Non-Covered Loans | Consumer & Other
Financing Receivable, Recorded Investment [Line Items]
Portfolio Loans	35,862	16,966
Total	36,744	16,977
Non-Covered Loans | Consumer & Other | Pass (1-6)
Financing Receivable, Recorded Investment [Line Items]
Total	36,740	16,972
Non-Covered Loans | Consumer & Other | Watch (7)
Financing Receivable, Recorded Investment [Line Items]
Total	4	5
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