Portfolio Loans Not Covered by Loss Share ("Non-covered") - Summary of Non-covered Loans by Category (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	$ 1,987,166	$ 1,897,074
Non-Covered Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Portfolio Loans	1,987,144	1,897,412
Unearned loan costs, net	22	(338)
Total	1,987,166	1,897,074
Non-Covered Loans | Real Estate Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Portfolio Loans	1,095,056	1,122,751
Non-Covered Loans | Real Estate Loans | Construction and Land Development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Portfolio Loans	146,236	140,147
Non-Covered Loans | Real Estate Loans | Commercial Real Estate Investor Owned
Accounts, Notes, Loans and Financing Receivable [Line Items]
Portfolio Loans	476,501	477,154
Non-Covered Loans | Real Estate Loans | Commercial Real Estate Owner Occupied
Accounts, Notes, Loans and Financing Receivable [Line Items]
Portfolio Loans	325,379	334,416
Non-Covered Loans | Real Estate Loans | Residential Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Portfolio Loans	146,940	171,034
Non-Covered Loans | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Portfolio Loans	880,394	763,202
Non-Covered Loans | Consumer & other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Portfolio Loans	11,694	11,459
Total	$ 11,716	$ 11,121