Loans Held for Investment (LHFI) and Allowance for Loan Losses, excluding Covered Loans Part 4 (Details) (USD $)	1 Months Ended	6 Months Ended
	Dec. 31, 2010	Jun. 30, 2011
Financing Receivable, Recorded Investment, Aging [Abstract]
Past Due 30 - 89 Days	$ 40,881,000	$ 60,348,000
Past Due Greater Than 90 Days	3,608,000	6,994,000
Total Past Due	44,489,000	67,342,000
Nonaccrual	142,923,000	121,018,000
Current Loans	5,872,830,000	5,717,956,000
Total LHFI, Excluding Covered Loans	6,060,242,000	5,906,316,000
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	19,400,000	31,700,000
Covered Serviced Financing Receivable Available for Repurchase, Recorded Investment, Equal to Greater than 90 Days Past Due	15,800,000	24,700,000
Percentage of Outstanding Principal To Be Repurchased Under GNMA Optional Repurchase Program (in hundredths)		100.00%
Payment to Acquire securities Sold Under Optional Repurchase Program	53,900,000
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	1,651,000	7,150,000
Past Due Greater Than 90 Days		1,506,000
Total Past Due	1,651,000	8,656,000
Nonaccrual	57,831,000	46,058,000
Current Loans	523,834,000	456,153,000
Total LHFI, Excluding Covered Loans	583,316,000	510,867,000
Real Estate Secured Financing Receivable [Member] | Residential Financing Receivable [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Past Due 30 - 89 Days	11,654,000	11,847,000
Past Due Greater Than 90 Days	1,278,000	2,769,000
Total Past Due	12,932,000	14,616,000
Nonaccrual	30,313,000	23,604,000
Current Loans	1,688,811,000	1,699,524,000
Total LHFI, Excluding Covered Loans	1,732,056,000	1,737,744,000
Real Estate Secured Financing Receivable [Member] | Nonresidential Properties Financing Receivables [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Past Due 30 - 89 Days	9,149,000	25,723,000
Past Due Greater Than 90 Days	31,000	28,000
Total Past Due	9,180,000	25,751,000
Nonaccrual	29,013,000	29,055,000
Current Loans	1,459,915,000	1,402,522,000
Total LHFI, Excluding Covered Loans	1,498,108,000	1,457,328,000
Real Estate Secured Financing Receivable [Member] | Other Real Estate Secured Financing Receivable [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Past Due 30 - 89 Days	441,000	2,033,000
Total Past Due	441,000	2,033,000
Nonaccrual	6,154,000	5,120,000
Current Loans	225,368,000	201,644,000
Total LHFI, Excluding Covered Loans	231,963,000	208,797,000
Commercial And Industrial Loans [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Past Due 30 - 89 Days	4,178,000	3,974,000
Past Due Greater Than 90 Days	39,000	135,000
Total Past Due	4,217,000	4,109,000
Nonaccrual	16,107,000	15,180,000
Current Loans	1,048,045,000	1,062,838,000
Total LHFI, Excluding Covered Loans	1,068,369,000	1,082,127,000
Consumer Loans Financing Receivable [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Past Due 30 - 89 Days	13,741,000	9,403,000
Past Due Greater Than 90 Days	2,260,000	2,556,000
Total Past Due	16,001,000	11,959,000
Nonaccrual	2,112,000	996,000
Current Loans	384,052,000	319,077,000
Total LHFI, Excluding Covered Loans	402,165,000	332,032,000
Other Loans Financing Receivable [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Past Due 30 - 89 Days	67,000	218,000
Total Past Due	67,000	218,000
Nonaccrual	1,393,000	1,005,000
Current Loans	542,805,000	576,198,000
Total LHFI, Excluding Covered Loans	544,265,000	577,421,000
Construction Land Development And Other Financing Receivable [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total LHFI, Excluding Covered Loans	583,316,000	510,867,000
Residential Financing Receivable [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total LHFI, Excluding Covered Loans	1,732,056,000	1,737,744,000
Nonresidential Properties Financing Receivables [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total LHFI, Excluding Covered Loans	1,498,108,000	1,457,328,000
Other Real Estate Secured Financing Receivable [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total LHFI, Excluding Covered Loans	$ 231,963,000	$ 208,797,000