Loans Held for Investment (LHFI) and Allowance for Loan Losses Part 4 (Details) (USD $)	3 Months Ended
	Mar. 31, 2012		Dec. 31, 2011
Financing Receivable, Recorded Investment, Aging [Abstract]
Past Due 30 - 89 Days	$ 28,924,000		$ 34,265,000
Past Due Greater Than 90 Days	1,551,000	[1]	4,230,000	[1]
Total Past Due	30,475,000		38,495,000
Nonaccrual	105,773,000		110,458,000
Current Loans	5,638,505,000		5,708,531,000
Total LHFI	5,774,753,000		5,857,484,000
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	41,000,000		43,600,000
Covered Serviced Financing Receivable Available for Repurchase, Recorded Investment, Equal to Greater than 90 Days Past Due	39,500,000		39,400,000
Percentage of Outstanding Principal To Be Repurchased Under GNMA Optional Repurchase Program (in hundredths)	100.00%
Construction Land Development And Other Financing Receivable [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total LHFI	465,486,000		474,082,000
Residential Financing Receivable [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total LHFI	1,722,357,000		1,760,930,000
Nonresidential Properties Financing Receivables [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total LHFI	1,419,902,000		1,425,774,000
Other Real Estate Secured Financing Receivable [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total LHFI	199,400,000		204,849,000
Real Estate Secured Financing Receivable [Member] | Construction Land Development And Other Financing Receivable [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Past Due 30 - 89 Days	3,248,000		1,784,000
Past Due Greater Than 90 Days	20,000	[1]	1,657,000	[1]
Total Past Due	3,268,000		3,441,000
Nonaccrual	38,023,000		40,413,000
Current Loans	424,195,000		430,228,000
Total LHFI	465,486,000		474,082,000
Real Estate Secured Financing Receivable [Member] | Residential Financing Receivable [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Past Due 30 - 89 Days	8,385,000		9,755,000
Past Due Greater Than 90 Days	1,220,000	[1]	1,306,000	[1]
Total Past Due	9,605,000		11,061,000
Nonaccrual	24,446,000		24,348,000
Current Loans	1,688,306,000		1,725,521,000
Total LHFI	1,722,357,000		1,760,930,000
Real Estate Secured Financing Receivable [Member] | Nonresidential Properties Financing Receivables [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Past Due 30 - 89 Days	7,594,000		9,925,000
Past Due Greater Than 90 Days	0	[1]	0	[1]
Total Past Due	7,594,000		9,925,000
Nonaccrual	33,034,000		23,981,000
Current Loans	1,379,274,000		1,391,868,000
Total LHFI	1,419,902,000		1,425,774,000
Real Estate Secured Financing Receivable [Member] | Other Real Estate Secured Financing Receivable [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Past Due 30 - 89 Days	1,342,000		879,000
Past Due Greater Than 90 Days	27,000	[1]	0	[1]
Total Past Due	1,369,000		879,000
Nonaccrual	4,557,000		5,871,000
Current Loans	193,474,000		198,099,000
Total LHFI	199,400,000		204,849,000
Commercial And Industrial Loans [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Past Due 30 - 89 Days	3,787,000		1,646,000
Past Due Greater Than 90 Days	8,000	[1]	769,000	[1]
Total Past Due	3,795,000		2,415,000
Nonaccrual	4,929,000		14,148,000
Current Loans	1,134,089,000		1,122,802,000
Total LHFI	1,142,813,000		1,139,365,000
Consumer Loans Financing Receivable [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Past Due 30 - 89 Days	3,685,000		7,172,000
Past Due Greater Than 90 Days	276,000	[1]	498,000	[1]
Total Past Due	3,961,000		7,670,000
Nonaccrual	536,000		825,000
Current Loans	206,216,000		235,261,000
Total LHFI	210,713,000		243,756,000
Other Loans Financing Receivable [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Past Due 30 - 89 Days	883,000		3,104,000
Past Due Greater Than 90 Days	0	[1]	0	[1]
Total Past Due	883,000		3,104,000
Nonaccrual	248,000		872,000
Current Loans	612,951,000		604,752,000
Total LHFI	$ 614,082,000		$ 608,728,000

[1] Past due greater than 90 days but still accruing interest