Loans Held for Investment (LHFI) and Allowance for Loan Losses, excluding Covered Loans Part 6 (Details) (USD $)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010
Financing Receivable, Modifications [Line Items]
Nonaccrual	$ 110,458,000	$ 142,923,000
Loans to related party	54,400,000	77,900,000
New loan advances to related party	167,100,000
Loan repayment by related party	170,800,000
Loan decreases from changes in executive officers and directors	19,800,000
Nonaccrual loans considered for impairment analysis	110,500,000	142,900,000
Minimum loan amount for loan to be individually assessed for impairment	500,000
Financing Receivable, Excluding Covered Loans, Troubled Debt Recorded Investment	34,200,000	19,200,000
Financing Receivable, Excluding Covered Loans, Related Allowance	4,500,000	1,900,000
Financing Receivable, Excluding Covered Loans, Related Charge-offs	1,900,000	2,100,000
Loan Amount Used as Baseline in Credit Quality Review For Loan Policy	1,000,000	1,000,000
Credit Amount Used as Baseline in Evaluating Residential Real Estate Development and Non-owner Occupied Commercial Real Estate For Loan Policy	100,000	100,000
Charge-off Amount Used as Baseline in Credit Quality Review For Loan Policy	25,000	25,000
Troubled Debt Restructurings [Abstract]
Number of Contracts	45
Pre-Modification Outstanding Recorded Investment	32,040,000
Post-Modification Outstanding Recorded Investment	29,280,000
Troubled Debt Restructurings that Subsequently Defaulted [Abstract]
Number of Contracts	6
Recorded Investment	3,237,000
Troubled Debt Restructurings [Member]
Financing Receivable, Modifications [Line Items]
Accruing	1,023,000	318,000
Nonaccrual	33,164,000	18,898,000
Total Troubled Debt Restructurings by Type	34,187,000	19,216,000
Troubled Debt Restructurings [Member] | Construction, Land Development And Other Financing Receivable [Member]
Financing Receivable, Modifications [Line Items]
Accruing	241,000	0
Nonaccrual	14,041,000	3,181,000
Total Troubled Debt Restructurings by Type	14,282,000	3,181,000
Troubled Debt Restructurings [Abstract]
Number of Contracts	26
Pre-Modification Outstanding Recorded Investment	16,200,000
Troubled Debt Restructurings [Member] | Residential Financing Receivable [Member]
Financing Receivable, Modifications [Line Items]
Accruing	782,000	318,000
Nonaccrual	3,485,000	1,488,000
Total Troubled Debt Restructurings by Type	4,267,000	1,806,000
Troubled Debt Restructurings [Abstract]
Number of Contracts	17
Pre-Modification Outstanding Recorded Investment	3,843,000
Post-Modification Outstanding Recorded Investment	3,793,000
Troubled Debt Restructurings [Member] | Nonresidential Properties Financing Receivables [Member]
Financing Receivable, Modifications [Line Items]
Accruing	0	0
Nonaccrual	4,135,000	2,232,000
Total Troubled Debt Restructurings by Type	4,135,000	2,232,000
Troubled Debt Restructurings [Member] | Commercial And Industrial Loans [Member]
Financing Receivable, Modifications [Line Items]
Accruing	0	0
Nonaccrual	11,503,000	11,997,000
Total Troubled Debt Restructurings by Type	11,503,000	11,997,000
Troubled Debt Restructurings [Abstract]
Number of Contracts	2
Pre-Modification Outstanding Recorded Investment	11,997,000
Post-Modification Outstanding Recorded Investment	11,503,000
Troubled Debt Restructurings that Subsequently Defaulted [Member] | Construction, Land Development And Other Financing Receivable [Member]
Troubled Debt Restructurings [Abstract]
Post-Modification Outstanding Recorded Investment	13,984,000
Troubled Debt Restructurings that Subsequently Defaulted [Abstract]
Number of Contracts	5
Recorded Investment	3,058,000
Troubled Debt Restructurings that Subsequently Defaulted [Member] | Residential Financing Receivable [Member]
Troubled Debt Restructurings that Subsequently Defaulted [Abstract]
Number of Contracts	1
Recorded Investment	$ 179,000