Loans Held for Investment (LHFI) and Allowance for Loan Losses, excluding Covered Loans Part 3 (Details) (USD $)	Dec. 31, 2011	Dec. 31, 2010
Financing Receivable Aging [Abstract]
Current	$ 5,708,531,000	$ 5,872,830,000
Past Due 30 - 89 Days	34,265,000	40,881,000
Nonaccrual	110,458,000	142,923,000
Total LHFI, Excluding Covered Loans	5,857,484,000	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	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
Construction, Land Development And Other Financing Receivable [Member]
Financing Receivable Aging [Abstract]
Total LHFI, Excluding Covered Loans	474,082,000	583,316,000
Residential Financing Receivable [Member]
Financing Receivable Aging [Abstract]
Total LHFI, Excluding Covered Loans	1,760,930,000	1,732,056,000
Nonresidential Properties Financing Receivables [Member]
Financing Receivable Aging [Abstract]
Total LHFI, Excluding Covered Loans	1,425,774,000	1,498,108,000
Other Real Estate Secured Financing Receivable [Member]
Financing Receivable Aging [Abstract]
Total LHFI, Excluding Covered Loans	204,849,000	231,963,000
Real Estate Secured Financing Receivable [Member] | Construction, Land Development And Other Financing Receivable [Member]
Financing Receivable Aging [Abstract]
Current	430,228,000	523,834,000
Past Due 30 - 89 Days	1,784,000	1,651,000
Nonaccrual	40,413,000	57,831,000
Total LHFI, Excluding Covered Loans	474,082,000	583,316,000
Real Estate Secured Financing Receivable [Member] | Residential Financing Receivable [Member]
Financing Receivable Aging [Abstract]
Current	1,725,521,000	1,688,811,000
Past Due 30 - 89 Days	9,755,000	11,654,000
Nonaccrual	24,348,000	30,313,000
Total LHFI, Excluding Covered Loans	1,760,930,000	1,732,056,000
Real Estate Secured Financing Receivable [Member] | Nonresidential Properties Financing Receivables [Member]
Financing Receivable Aging [Abstract]
Current	1,391,868,000	1,459,915,000
Past Due 30 - 89 Days	9,925,000	9,149,000
Nonaccrual	23,981,000	29,013,000
Total LHFI, Excluding Covered Loans	1,425,774,000	1,498,108,000
Real Estate Secured Financing Receivable [Member] | Other Real Estate Secured Financing Receivable [Member]
Financing Receivable Aging [Abstract]
Current	198,099,000	225,368,000
Past Due 30 - 89 Days	879,000	441,000
Nonaccrual	5,871,000	6,154,000
Total LHFI, Excluding Covered Loans	204,849,000	231,963,000
Commercial And Industrial Loans Financing Receivable [Member]
Financing Receivable Aging [Abstract]
Total LHFI, Excluding Covered Loans	1,139,365,000	1,068,369,000
Consumer Loans Financing Receivable [Member]
Financing Receivable Aging [Abstract]
Current	235,261,000	384,052,000
Past Due 30 - 89 Days	7,172,000	13,741,000
Nonaccrual	825,000	2,112,000
Total LHFI, Excluding Covered Loans	243,756,000	402,165,000
Other Loans Financing Receivable [Member]
Financing Receivable Aging [Abstract]
Current	604,752,000	542,805,000
Past Due 30 - 89 Days	3,104,000	67,000
Nonaccrual	872,000	1,393,000
Total LHFI, Excluding Covered Loans	608,728,000	544,265,000
Commercial Portfolio Segment [Member]
Financing Receivable [Abstract]
Financing Receivable Commercial	3,924,755,000	3,990,244,000
Commercial Portfolio Segment [Member] | Pass [Member]
Financing Receivable [Abstract]
Financing Receivable Commercial	3,554,041,000	3,544,306,000
Commercial Portfolio Segment [Member] | Special Mention [Member]
Financing Receivable [Abstract]
Financing Receivable Commercial	84,848,000	88,129,000
Commercial Portfolio Segment [Member] | Substandard [Member]
Financing Receivable [Abstract]
Financing Receivable Commercial	284,694,000	355,078,000
Commercial Portfolio Segment [Member] | Doubtful [Member]
Financing Receivable [Abstract]
Financing Receivable Commercial	1,172,000	2,731,000
Commercial Portfolio Segment [Member] | Real Estate Secured Financing Receivable [Member] | Construction, Land Development And Other Financing Receivable [Member]
Financing Receivable [Abstract]
Financing Receivable Commercial	425,182,000	526,761,000
Commercial Portfolio Segment [Member] | Real Estate Secured Financing Receivable [Member] | Construction, Land Development And Other Financing Receivable [Member] | Pass [Member]
Financing Receivable [Abstract]
Financing Receivable Commercial	308,618,000	347,287,000
Commercial Portfolio Segment [Member] | Real Estate Secured Financing Receivable [Member] | Construction, Land Development And Other Financing Receivable [Member] | Special Mention [Member]
Financing Receivable [Abstract]
Financing Receivable Commercial	26,273,000	44,459,000
Commercial Portfolio Segment [Member] | Real Estate Secured Financing Receivable [Member] | Construction, Land Development And Other Financing Receivable [Member] | Substandard [Member]
Financing Receivable [Abstract]
Financing Receivable Commercial	90,175,000	134,503,000
Commercial Portfolio Segment [Member] | Real Estate Secured Financing Receivable [Member] | Construction, Land Development And Other Financing Receivable [Member] | Doubtful [Member]
Financing Receivable [Abstract]
Financing Receivable Commercial	116,000	512,000
Commercial Portfolio Segment [Member] | Real Estate Secured Financing Receivable [Member] | Residential Financing Receivable [Member]
Financing Receivable [Abstract]
Financing Receivable Commercial	135,621,000	139,949,000
Commercial Portfolio Segment [Member] | Real Estate Secured Financing Receivable [Member] | Residential Financing Receivable [Member] | Pass [Member]
Financing Receivable [Abstract]
Financing Receivable Commercial	119,155,000	113,776,000
Commercial Portfolio Segment [Member] | Real Estate Secured Financing Receivable [Member] | Residential Financing Receivable [Member] | Special Mention [Member]
Financing Receivable [Abstract]
Financing Receivable Commercial	142,000	780,000
Commercial Portfolio Segment [Member] | Real Estate Secured Financing Receivable [Member] | Residential Financing Receivable [Member] | Substandard [Member]
Financing Receivable [Abstract]
Financing Receivable Commercial	16,324,000	25,167,000
Commercial Portfolio Segment [Member] | Real Estate Secured Financing Receivable [Member] | Residential Financing Receivable [Member] | Doubtful [Member]
Financing Receivable [Abstract]
Financing Receivable Commercial	0	226,000
Commercial Portfolio Segment [Member] | Real Estate Secured Financing Receivable [Member] | Nonresidential Properties Financing Receivables [Member]
Financing Receivable [Abstract]
Financing Receivable Commercial	1,424,641,000	1,497,133,000
Commercial Portfolio Segment [Member] | Real Estate Secured Financing Receivable [Member] | Nonresidential Properties Financing Receivables [Member] | Pass [Member]
Financing Receivable [Abstract]
Financing Receivable Commercial	1,287,886,000	1,353,794,000
Commercial Portfolio Segment [Member] | Real Estate Secured Financing Receivable [Member] | Nonresidential Properties Financing Receivables [Member] | Special Mention [Member]
Financing Receivable [Abstract]
Financing Receivable Commercial	26,232,000	16,858,000
Commercial Portfolio Segment [Member] | Real Estate Secured Financing Receivable [Member] | Nonresidential Properties Financing Receivables [Member] | Substandard [Member]
Financing Receivable [Abstract]
Financing Receivable Commercial	110,472,000	126,050,000
Commercial Portfolio Segment [Member] | Real Estate Secured Financing Receivable [Member] | Nonresidential Properties Financing Receivables [Member] | Doubtful [Member]
Financing Receivable [Abstract]
Financing Receivable Commercial	51,000	431,000
Commercial Portfolio Segment [Member] | Real Estate Secured Financing Receivable [Member] | Other Real Estate Secured Financing Receivable [Member]
Financing Receivable [Abstract]
Financing Receivable Commercial	198,214,000	223,620,000
Commercial Portfolio Segment [Member] | Real Estate Secured Financing Receivable [Member] | Other Real Estate Secured Financing Receivable [Member] | Pass [Member]
Financing Receivable [Abstract]
Financing Receivable Commercial	188,772,000	216,022,000
Commercial Portfolio Segment [Member] | Real Estate Secured Financing Receivable [Member] | Other Real Estate Secured Financing Receivable [Member] | Special Mention [Member]
Financing Receivable [Abstract]
Financing Receivable Commercial	130,000	180,000
Commercial Portfolio Segment [Member] | Real Estate Secured Financing Receivable [Member] | Other Real Estate Secured Financing Receivable [Member] | Substandard [Member]
Financing Receivable [Abstract]
Financing Receivable Commercial	9,312,000	7,418,000
Commercial Portfolio Segment [Member] | Real Estate Secured Financing Receivable [Member] | Other Real Estate Secured Financing Receivable [Member] | Doubtful [Member]
Financing Receivable [Abstract]
Financing Receivable Commercial	0	0
Commercial Portfolio Segment [Member] | Commercial And Industrial Loans Financing Receivable [Member]
Financing Receivable [Abstract]
Financing Receivable Commercial	1,137,584,000	1,063,158,000
Commercial Portfolio Segment [Member] | Commercial And Industrial Loans Financing Receivable [Member] | Pass [Member]
Financing Receivable [Abstract]
Financing Receivable Commercial	1,048,556,000	977,793,000
Commercial Portfolio Segment [Member] | Commercial And Industrial Loans Financing Receivable [Member] | Special Mention [Member]
Financing Receivable [Abstract]
Financing Receivable Commercial	32,046,000	25,642,000
Commercial Portfolio Segment [Member] | Commercial And Industrial Loans Financing Receivable [Member] | Substandard [Member]
Financing Receivable [Abstract]
Financing Receivable Commercial	56,577,000	58,307,000
Commercial Portfolio Segment [Member] | Commercial And Industrial Loans Financing Receivable [Member] | Doubtful [Member]
Financing Receivable [Abstract]
Financing Receivable Commercial	405,000	1,416,000
Commercial Portfolio Segment [Member] | Consumer Loans Financing Receivable [Member]
Financing Receivable [Abstract]
Financing Receivable Commercial	668,000	524,000
Commercial Portfolio Segment [Member] | Consumer Loans Financing Receivable [Member] | Pass [Member]
Financing Receivable [Abstract]
Financing Receivable Commercial	643,000	524,000
Commercial Portfolio Segment [Member] | Consumer Loans Financing Receivable [Member] | Special Mention [Member]
Financing Receivable [Abstract]
Financing Receivable Commercial	25,000	0
Commercial Portfolio Segment [Member] | Consumer Loans Financing Receivable [Member] | Substandard [Member]
Financing Receivable [Abstract]
Financing Receivable Commercial	0	0
Commercial Portfolio Segment [Member] | Consumer Loans Financing Receivable [Member] | Doubtful [Member]
Financing Receivable [Abstract]
Financing Receivable Commercial	0	0
Commercial Portfolio Segment [Member] | Other Loans Financing Receivable [Member]
Financing Receivable [Abstract]
Financing Receivable Commercial	602,845,000	539,099,000
Commercial Portfolio Segment [Member] | Other Loans Financing Receivable [Member] | Pass [Member]
Financing Receivable [Abstract]
Financing Receivable Commercial	600,411,000	535,110,000
Commercial Portfolio Segment [Member] | Other Loans Financing Receivable [Member] | Special Mention [Member]
Financing Receivable [Abstract]
Financing Receivable Commercial	0	210,000
Commercial Portfolio Segment [Member] | Other Loans Financing Receivable [Member] | Substandard [Member]
Financing Receivable [Abstract]
Financing Receivable Commercial	1,834,000	3,633,000
Commercial Portfolio Segment [Member] | Other Loans Financing Receivable [Member] | Doubtful [Member]
Financing Receivable [Abstract]
Financing Receivable Commercial	600,000	146,000
Consumer Portfolio Segment [Member]
Financing Receivable Aging [Abstract]
Current	1,893,658,000	2,016,434,000
Past Due 30 - 89 Days	16,356,000	24,389,000
Past Due Greater Than 90 Days	1,804,000	3,538,000
Nonaccrual	20,911,000	25,637,000
Subtotal	1,932,729,000	2,069,998,000
Consumer Portfolio Segment [Member] | Real Estate Secured Financing Receivable [Member] | Construction, Land Development And Other Financing Receivable [Member]
Financing Receivable Aging [Abstract]
Current	47,253,000	53,797,000
Past Due 30 - 89 Days	353,000	223,000
Past Due Greater Than 90 Days	0	0
Nonaccrual	1,294,000	2,535,000
Subtotal	48,900,000	56,555,000
Consumer Portfolio Segment [Member] | Real Estate Secured Financing Receivable [Member] | Residential Financing Receivable [Member]
Financing Receivable Aging [Abstract]
Current	1,596,800,000	1,559,611,000
Past Due 30 - 89 Days	8,477,000	10,302,000
Past Due Greater Than 90 Days	1,306,000	1,278,000
Nonaccrual	18,726,000	20,916,000
Subtotal	1,625,309,000	1,592,107,000
Consumer Portfolio Segment [Member] | Real Estate Secured Financing Receivable [Member] | Nonresidential Properties Financing Receivables [Member]
Financing Receivable Aging [Abstract]
Current	1,133,000	975,000
Past Due 30 - 89 Days	0	0
Past Due Greater Than 90 Days	0	0
Nonaccrual	0	0
Subtotal	1,133,000	975,000
Consumer Portfolio Segment [Member] | Real Estate Secured Financing Receivable [Member] | Other Real Estate Secured Financing Receivable [Member]
Financing Receivable Aging [Abstract]
Current	6,405,000	8,282,000
Past Due 30 - 89 Days	201,000	26,000
Past Due Greater Than 90 Days	0	0
Nonaccrual	29,000	35,000
Subtotal	6,635,000	8,343,000
Consumer Portfolio Segment [Member] | Commercial And Industrial Loans Financing Receivable [Member]
Financing Receivable Aging [Abstract]
Current	1,626,000	5,075,000
Past Due 30 - 89 Days	118,000	97,000
Past Due Greater Than 90 Days	0	0
Nonaccrual	37,000	39,000
Subtotal	1,781,000	5,211,000
Consumer Portfolio Segment [Member] | Consumer Loans Financing Receivable [Member]
Financing Receivable Aging [Abstract]
Current	234,593,000	383,528,000
Past Due 30 - 89 Days	7,172,000	13,741,000
Past Due Greater Than 90 Days	498,000	2,260,000
Nonaccrual	825,000	2,112,000
Subtotal	243,088,000	401,641,000
Consumer Portfolio Segment [Member] | Other Loans Financing Receivable [Member]
Financing Receivable Aging [Abstract]
Current	5,848,000	5,166,000
Past Due 30 - 89 Days	35,000	0
Past Due Greater Than 90 Days	0	0
Nonaccrual	0	0
Subtotal	$ 5,883,000	$ 5,166,000