Loans Held for Investment (LHFI) and Allowance for Loan Losses, excluding Covered Loans Part 3 (Details) (USD $)	Jun. 30, 2011	Dec. 31, 2010
Financing Receivable Aging [Abstract]
Current	$ 5,717,956,000	$ 5,872,830,000
Past Due 30 - 89 Days	60,348,000	40,881,000
Nonaccrual	121,018,000	142,923,000
Total LHFI, Excluding Covered Loans	5,906,316,000	6,060,242,000
Number of Days used as Baseline in Evaluating Collateral Documentation Exceptions For Loan Policy (in days)	90 D
Loan Amount Used as Baseline in Credit Quality Review For Loan Policy	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
Charge-off Amount Used as Baseline in Credit Quality Review For Loan Policy	25,000
Real Estate Secured Financing Receivable [Member] | Construction Land Development And Other Financing Receivable [Member] | Commercial Portfolio Segment [Member]
Financing Receivable [Abstract]
Financing Receivable Commercial	457,539,000	526,761,000
Real Estate Secured Financing Receivable [Member] | Construction Land Development And Other Financing Receivable [Member] | Commercial Portfolio Segment [Member] | Pass [Member]
Financing Receivable [Abstract]
Financing Receivable Commercial	303,186,000	347,287,000
Real Estate Secured Financing Receivable [Member] | Construction Land Development And Other Financing Receivable [Member] | Commercial Portfolio Segment [Member] | Special Mention [Member]
Financing Receivable [Abstract]
Financing Receivable Commercial	37,323,000	44,459,000
Real Estate Secured Financing Receivable [Member] | Construction Land Development And Other Financing Receivable [Member] | Commercial Portfolio Segment [Member] | Substandard [Member]
Financing Receivable [Abstract]
Financing Receivable Commercial	116,918,000	134,503,000
Real Estate Secured Financing Receivable [Member] | Construction Land Development And Other Financing Receivable [Member] | Commercial Portfolio Segment [Member] | Doubtful [Member]
Financing Receivable [Abstract]
Financing Receivable Commercial	112,000	512,000
Real Estate Secured Financing Receivable [Member] | Residential Financing Receivable [Member] | Commercial Portfolio Segment [Member]
Financing Receivable [Abstract]
Financing Receivable Commercial	135,538,000	139,949,000
Real Estate Secured Financing Receivable [Member] | Residential Financing Receivable [Member] | Commercial Portfolio Segment [Member] | Pass [Member]
Financing Receivable [Abstract]
Financing Receivable Commercial	115,711,000	113,776,000
Real Estate Secured Financing Receivable [Member] | Residential Financing Receivable [Member] | Commercial Portfolio Segment [Member] | Special Mention [Member]
Financing Receivable [Abstract]
Financing Receivable Commercial	1,348,000	780,000
Real Estate Secured Financing Receivable [Member] | Residential Financing Receivable [Member] | Commercial Portfolio Segment [Member] | Substandard [Member]
Financing Receivable [Abstract]
Financing Receivable Commercial	18,307,000	25,167,000
Real Estate Secured Financing Receivable [Member] | Residential Financing Receivable [Member] | Commercial Portfolio Segment [Member] | Doubtful [Member]
Financing Receivable [Abstract]
Financing Receivable Commercial	172,000	226,000
Real Estate Secured Financing Receivable [Member] | Nonresidential Properties Financing Receivables [Member] | Commercial Portfolio Segment [Member]
Financing Receivable [Abstract]
Financing Receivable Commercial	1,456,393,000	1,497,133,000
Real Estate Secured Financing Receivable [Member] | Nonresidential Properties Financing Receivables [Member] | Commercial Portfolio Segment [Member] | Pass [Member]
Financing Receivable [Abstract]
Financing Receivable Commercial	1,311,071,000	1,353,794,000
Real Estate Secured Financing Receivable [Member] | Nonresidential Properties Financing Receivables [Member] | Commercial Portfolio Segment [Member] | Special Mention [Member]
Financing Receivable [Abstract]
Financing Receivable Commercial	20,493,000	16,858,000
Real Estate Secured Financing Receivable [Member] | Nonresidential Properties Financing Receivables [Member] | Commercial Portfolio Segment [Member] | Substandard [Member]
Financing Receivable [Abstract]
Financing Receivable Commercial	124,568,000	126,050,000
Real Estate Secured Financing Receivable [Member] | Nonresidential Properties Financing Receivables [Member] | Commercial Portfolio Segment [Member] | Doubtful [Member]
Financing Receivable [Abstract]
Financing Receivable Commercial	261,000	431,000
Real Estate Secured Financing Receivable [Member] | Other Real Estate Secured Financing Receivable [Member] | Commercial Portfolio Segment [Member]
Financing Receivable [Abstract]
Financing Receivable Commercial	200,980,000	223,620,000
Real Estate Secured Financing Receivable [Member] | Other Real Estate Secured Financing Receivable [Member] | Commercial Portfolio Segment [Member] | Pass [Member]
Financing Receivable [Abstract]
Financing Receivable Commercial	192,286,000	216,022,000
Real Estate Secured Financing Receivable [Member] | Other Real Estate Secured Financing Receivable [Member] | Commercial Portfolio Segment [Member] | Special Mention [Member]
Financing Receivable [Abstract]
Financing Receivable Commercial	315,000	180,000
Real Estate Secured Financing Receivable [Member] | Other Real Estate Secured Financing Receivable [Member] | Commercial Portfolio Segment [Member] | Substandard [Member]
Financing Receivable [Abstract]
Financing Receivable Commercial	8,379,000	7,418,000
Commercial And Industrial Loans Financing Receivable [Member] | Commercial Portfolio Segment [Member]
Financing Receivable [Abstract]
Financing Receivable Commercial	1,078,649,000	1,063,158,000
Commercial And Industrial Loans Financing Receivable [Member] | Commercial Portfolio Segment [Member] | Pass [Member]
Financing Receivable [Abstract]
Financing Receivable Commercial	998,915,000	977,793,000
Commercial And Industrial Loans Financing Receivable [Member] | Commercial Portfolio Segment [Member] | Special Mention [Member]
Financing Receivable [Abstract]
Financing Receivable Commercial	27,064,000	25,642,000
Commercial And Industrial Loans Financing Receivable [Member] | Commercial Portfolio Segment [Member] | Substandard [Member]
Financing Receivable [Abstract]
Financing Receivable Commercial	51,198,000	58,307,000
Commercial And Industrial Loans Financing Receivable [Member] | Commercial Portfolio Segment [Member] | Doubtful [Member]
Financing Receivable [Abstract]
Financing Receivable Commercial	1,472,000	1,416,000
Consumer Loans Financing Receivable [Member] | Commercial Portfolio Segment [Member]
Financing Receivable [Abstract]
Financing Receivable Commercial	1,282,000	524,000
Consumer Loans Financing Receivable [Member] | Commercial Portfolio Segment [Member] | Pass [Member]
Financing Receivable [Abstract]
Financing Receivable Commercial	1,282,000	524,000
Other Loans Financing Receivable [Member] | Commercial Portfolio Segment [Member]
Financing Receivable [Abstract]
Financing Receivable Commercial	571,196,000	539,099,000
Other Loans Financing Receivable [Member] | Commercial Portfolio Segment [Member] | Pass [Member]
Financing Receivable [Abstract]
Financing Receivable Commercial	567,213,000	535,110,000
Other Loans Financing Receivable [Member] | Commercial Portfolio Segment [Member] | Special Mention [Member]
Financing Receivable [Abstract]
Financing Receivable Commercial		210,000
Other Loans Financing Receivable [Member] | Commercial Portfolio Segment [Member] | Substandard [Member]
Financing Receivable [Abstract]
Financing Receivable Commercial	3,858,000	3,633,000
Other Loans Financing Receivable [Member] | Commercial Portfolio Segment [Member] | Doubtful [Member]
Financing Receivable [Abstract]
Financing Receivable Commercial	125,000	146,000
Commercial Portfolio Segment [Member]
Financing Receivable [Abstract]
Financing Receivable Commercial	3,901,577,000	3,990,244,000
Commercial Portfolio Segment [Member] | Pass [Member]
Financing Receivable [Abstract]
Financing Receivable Commercial	3,489,664,000	3,544,306,000
Commercial Portfolio Segment [Member] | Special Mention [Member]
Financing Receivable [Abstract]
Financing Receivable Commercial	86,543,000	88,129,000
Commercial Portfolio Segment [Member] | Substandard [Member]
Financing Receivable [Abstract]
Financing Receivable Commercial	323,228,000	355,078,000
Commercial Portfolio Segment [Member] | Doubtful [Member]
Financing Receivable [Abstract]
Financing Receivable Commercial	2,142,000	2,731,000
Real Estate Secured Financing Receivable [Member] | Construction Land Development And Other Financing Receivable [Member] | Consumer Portfolio Segment [Member]
Financing Receivable Aging [Abstract]
Current	50,290,000	53,797,000
Past Due 30 - 89 Days	1,107,000	223,000
Past Due Greater Than 90 Days	210,000
Nonaccrual	1,721,000	2,535,000
Subtotal	53,328,000	56,555,000
Real Estate Secured Financing Receivable [Member] | Residential Financing Receivable [Member] | Consumer Portfolio Segment [Member]
Financing Receivable Aging [Abstract]
Current	1,570,576,000	1,559,611,000
Past Due 30 - 89 Days	10,798,000	10,302,000
Past Due Greater Than 90 Days	2,770,000	1,278,000
Nonaccrual	18,062,000	20,916,000
Subtotal	1,602,206,000	1,592,107,000
Real Estate Secured Financing Receivable [Member] | Nonresidential Properties Financing Receivables [Member] | Consumer Portfolio Segment [Member]
Financing Receivable Aging [Abstract]
Current	935,000	975,000
Subtotal	935,000	975,000
Real Estate Secured Financing Receivable [Member] | Other Real Estate Secured Financing Receivable [Member] | Consumer Portfolio Segment [Member]
Financing Receivable Aging [Abstract]
Current	7,779,000	8,282,000
Past Due 30 - 89 Days	6,000	26,000
Nonaccrual	32,000	35,000
Subtotal	7,817,000	8,343,000
Commercial And Industrial Loans Financing Receivable [Member] | Consumer Portfolio Segment [Member]
Financing Receivable Aging [Abstract]
Current	2,571,000	5,075,000
Past Due 30 - 89 Days	863,000	97,000
Nonaccrual	44,000	39,000
Subtotal	3,478,000	5,211,000
Consumer Loans Financing Receivable [Member] | Consumer Portfolio Segment [Member]
Financing Receivable Aging [Abstract]
Current	317,771,000	383,529,000
Past Due 30 - 89 Days	9,427,000	13,741,000
Past Due Greater Than 90 Days	2,556,000	2,260,000
Nonaccrual	996,000	2,111,000
Subtotal	330,750,000	401,641,000
Other Loans Financing Receivable [Member] | Consumer Portfolio Segment [Member]
Financing Receivable Aging [Abstract]
Current	6,225,000	5,166,000
Subtotal	6,225,000	5,166,000
Consumer Portfolio Segment [Member]
Financing Receivable Aging [Abstract]
Current	1,956,147,000	2,016,435,000
Past Due 30 - 89 Days	22,201,000	24,389,000
Past Due Greater Than 90 Days	5,536,000	3,538,000
Nonaccrual	20,855,000	25,636,000
Subtotal	2,004,739,000	2,069,998,000
Real Estate Secured Financing Receivable [Member] | Construction Land Development And Other Financing Receivable [Member]
Financing Receivable Aging [Abstract]
Current	456,153,000	523,834,000
Past Due 30 - 89 Days	7,150,000	1,651,000
Nonaccrual	46,058,000	57,831,000
Total LHFI, Excluding Covered Loans	510,867,000	583,316,000
Real Estate Secured Financing Receivable [Member] | Residential Financing Receivable [Member]
Financing Receivable Aging [Abstract]
Current	1,699,524,000	1,688,811,000
Past Due 30 - 89 Days	11,847,000	11,654,000
Nonaccrual	23,604,000	30,313,000
Total LHFI, Excluding Covered Loans	1,737,744,000	1,732,056,000
Real Estate Secured Financing Receivable [Member] | Nonresidential Properties Financing Receivables [Member]
Financing Receivable Aging [Abstract]
Current	1,402,522,000	1,459,915,000
Past Due 30 - 89 Days	25,723,000	9,149,000
Nonaccrual	29,055,000	29,013,000
Total LHFI, Excluding Covered Loans	1,457,328,000	1,498,108,000
Real Estate Secured Financing Receivable [Member] | Other Real Estate Secured Financing Receivable [Member]
Financing Receivable Aging [Abstract]
Current	201,644,000	225,368,000
Past Due 30 - 89 Days	2,033,000	441,000
Nonaccrual	5,120,000	6,154,000
Total LHFI, Excluding Covered Loans	208,797,000	231,963,000
Commercial And Industrial Loans Financing Receivable [Member]
Financing Receivable Aging [Abstract]
Total LHFI, Excluding Covered Loans	1,082,127,000	1,068,369,000
Consumer Loans Financing Receivable [Member]
Financing Receivable Aging [Abstract]
Current	319,077,000	384,052,000
Past Due 30 - 89 Days	9,403,000	13,741,000
Nonaccrual	996,000	2,112,000
Total LHFI, Excluding Covered Loans	332,032,000	402,165,000
Other Loans Financing Receivable [Member]
Financing Receivable Aging [Abstract]
Current	576,198,000	542,805,000
Past Due 30 - 89 Days	218,000	67,000
Nonaccrual	1,005,000	1,393,000
Total LHFI, Excluding Covered Loans	577,421,000	544,265,000
Construction Land Development And Other Financing Receivable [Member]
Financing Receivable Aging [Abstract]
Total LHFI, Excluding Covered Loans	510,867,000	583,316,000
Residential Financing Receivable [Member]
Financing Receivable Aging [Abstract]
Total LHFI, Excluding Covered Loans	1,737,744,000	1,732,056,000
Nonresidential Properties Financing Receivables [Member]
Financing Receivable Aging [Abstract]
Total LHFI, Excluding Covered Loans	1,457,328,000	1,498,108,000
Other Real Estate Secured Financing Receivable [Member]
Financing Receivable Aging [Abstract]
Total LHFI, Excluding Covered Loans	$ 208,797,000	$ 231,963,000