Loans Held for Investment (LHFI) and Allowance for Loan Losses, excluding Covered Loans Part 2 (Details) (USD $)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Loan and Lease Receivables, Impaired [Abstract]
Unpaid Principal Balance	$ 146,602,000	$ 188,809,000
Total LHFI With No Related Allowance Recorded	36,945,000	70,186,000
Total LHFI With An Allowance Recorded	73,513,000	72,737,000
Total Carrying Amount	110,458,000	142,923,000
Related Allowance	12,664,000	11,797,000
Average Recorded Investment	126,689,000	142,044,000
Maximum Concentration Of Loan as a Percentage of Total Loans Held For Investment (in hundredths)	10.00%
Nonaccrual Financing Receivable, Specifically Evaluated for Impairment	68,900,000	97,600,000
Nonaccrual Financing Receivable, Allowance for Credit Losses, Specifically Evaluated for Impairment	8,800,000	8,300,000
Nonaccrual Financing Receivable, Allowance For Credit Losses, Charge-offs, Specifically Evaluated For Impairment	21,500,000	33,000,000	29,100,000
Nonaccrual Financing Receivable Specifically Evaluated For Impairment, Allowance For Credit Losses, Provisions	7,500,000	11,500,000	20,700,000
Minimum loan amount for loan to be individually assessed for impairment	500,000
Nonaccrual Financing Receivable, Not Specifically Evaluated for Impairment	41,600,000	45,300,000
Nonaccrual Financing Receivable, Allowance for Credit Losses, Not Specifically Evaluated for Impairment	3,900,000	3,500,000
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
Real Estate Secured Financing Receivable [Member] | Construction, Land Development And Other Financing Receivable [Member]
Loan and Lease Receivables, Impaired [Abstract]
Unpaid Principal Balance	58,757,000	81,945,000
Total LHFI With No Related Allowance Recorded	11,123,000	33,201,000
Total LHFI With An Allowance Recorded	29,290,000	24,630,000
Total Carrying Amount	40,413,000	57,831,000
Related Allowance	6,547,000	6,782,000
Average Recorded Investment	49,122,000	69,817,000
Real Estate Secured Financing Receivable [Member] | Residential Financing Receivable [Member]
Loan and Lease Receivables, Impaired [Abstract]
Unpaid Principal Balance	33,746,000	41,475,000
Total LHFI With No Related Allowance Recorded	1,560,000	3,082,000
Total LHFI With An Allowance Recorded	22,788,000	27,231,000
Total Carrying Amount	24,348,000	30,313,000
Related Allowance	1,348,000	1,745,000
Average Recorded Investment	27,330,000	30,888,000
Real Estate Secured Financing Receivable [Member] | Nonresidential Properties Financing Receivables [Member]
Loan and Lease Receivables, Impaired [Abstract]
Unpaid Principal Balance	27,183,000	35,679,000
Total LHFI With No Related Allowance Recorded	13,770,000	18,582,000
Total LHFI With An Allowance Recorded	10,211,000	10,431,000
Total Carrying Amount	23,981,000	29,013,000
Related Allowance	2,431,000	1,579,000
Average Recorded Investment	26,497,000	23,535,000
Real Estate Secured Financing Receivable [Member] | Other Real Estate Secured Financing Receivable [Member]
Loan and Lease Receivables, Impaired [Abstract]
Unpaid Principal Balance	7,158,000	7,009,000
Total LHFI With No Related Allowance Recorded	1,548,000	5,042,000
Total LHFI With An Allowance Recorded	4,323,000	1,112,000
Total Carrying Amount	5,871,000	6,154,000
Related Allowance	1,007,000	96,000
Average Recorded Investment	6,013,000	4,126,000
Commercial And Industrial Loans Financing Receivable [Member]
Loan and Lease Receivables, Impaired [Abstract]
Unpaid Principal Balance	16,102,000	17,413,000
Total LHFI With No Related Allowance Recorded	8,724,000	9,172,000
Total LHFI With An Allowance Recorded	5,424,000	6,935,000
Total Carrying Amount	14,148,000	16,107,000
Related Allowance	1,137,000	1,514,000
Average Recorded Investment	15,127,000	11,369,000
Consumer Loans Financing Receivable [Member]
Loan and Lease Receivables, Impaired [Abstract]
Unpaid Principal Balance	1,097,000	2,420,000
Total LHFI With No Related Allowance Recorded	0	0
Total LHFI With An Allowance Recorded	825,000	2,112,000
Total Carrying Amount	825,000	2,112,000
Related Allowance	9,000	23,000
Average Recorded Investment	1,468,000	1,544,000
Other Loans Financing Receivable [Member]
Loan and Lease Receivables, Impaired [Abstract]
Unpaid Principal Balance	2,559,000	2,868,000
Total LHFI With No Related Allowance Recorded	220,000	1,107,000
Total LHFI With An Allowance Recorded	652,000	286,000
Total Carrying Amount	872,000	1,393,000
Related Allowance	185,000	58,000
Average Recorded Investment	$ 1,132,000	$ 765,000