Loans Held for Investment (LHFI) and Allowance for Loan Losses, excluding Covered Loans Part 3 (Details) (USD $)	Sep. 30, 2011	Dec. 31, 2010
Financing Receivable Aging [Abstract]
Current	$ 5,627,052,000	$ 5,872,830,000
Past Due 30 - 89 Days	53,916,000	40,881,000
Nonaccrual	99,578,000	142,923,000
Total LHFI, Excluding Covered Loans	5,783,712,000	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	429,725,000	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	305,155,000	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	28,014,000	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	96,487,000	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	69,000	512,000
Real Estate Secured Financing Receivable [Member] | Residential Financing Receivable [Member] | Commercial Portfolio Segment [Member]
Financing Receivable [Abstract]
Financing Receivable Commercial	135,586,000	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	118,644,000	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	147,000	780,000
Real Estate Secured Financing Receivable [Member] | Residential Financing Receivable [Member] | Commercial Portfolio Segment [Member] | Substandard [Member]
Financing Receivable [Abstract]
Financing Receivable Commercial	16,795,000	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	0	226,000
Real Estate Secured Financing Receivable [Member] | Nonresidential Properties Financing Receivables [Member] | Commercial Portfolio Segment [Member]
Financing Receivable [Abstract]
Financing Receivable Commercial	1,436,660,000	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	1,291,830,000	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	13,123,000	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	131,656,000	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	51,000	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	200,759,000	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	190,265,000	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	314,000	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	10,180,000	7,418,000
Commercial And Industrial Loans Financing Receivable [Member] | Commercial Portfolio Segment [Member]
Financing Receivable [Abstract]
Financing Receivable Commercial	1,081,350,000	1,063,158,000
Commercial And Industrial Loans Financing Receivable [Member] | Commercial Portfolio Segment [Member] | Pass [Member]
Financing Receivable [Abstract]
Financing Receivable Commercial	999,567,000	977,793,000
Commercial And Industrial Loans Financing Receivable [Member] | Commercial Portfolio Segment [Member] | Special Mention [Member]
Financing Receivable [Abstract]
Financing Receivable Commercial	24,922,000	25,642,000
Commercial And Industrial Loans Financing Receivable [Member] | Commercial Portfolio Segment [Member] | Substandard [Member]
Financing Receivable [Abstract]
Financing Receivable Commercial	55,456,000	58,307,000
Commercial And Industrial Loans Financing Receivable [Member] | Commercial Portfolio Segment [Member] | Doubtful [Member]
Financing Receivable [Abstract]
Financing Receivable Commercial	1,405,000	1,416,000
Consumer Loans Financing Receivable [Member] | Commercial Portfolio Segment [Member]
Financing Receivable [Abstract]
Financing Receivable Commercial	820,000	524,000
Consumer Loans Financing Receivable [Member] | Commercial Portfolio Segment [Member] | Pass [Member]
Financing Receivable [Abstract]
Financing Receivable Commercial	796,000	524,000
Consumer Loans Financing Receivable [Member] | Commercial Portfolio Segment [Member] | Special Mention [Member]
Financing Receivable [Abstract]
Financing Receivable Commercial	24,000
Other Loans Financing Receivable [Member] | Commercial Portfolio Segment [Member]
Financing Receivable [Abstract]
Financing Receivable Commercial	581,834,000	539,099,000
Other Loans Financing Receivable [Member] | Commercial Portfolio Segment [Member] | Pass [Member]
Financing Receivable [Abstract]
Financing Receivable Commercial	572,818,000	535,110,000
Other Loans Financing Receivable [Member] | Commercial Portfolio Segment [Member] | Special Mention [Member]
Financing Receivable [Abstract]
Financing Receivable Commercial	5,994,000	210,000
Other Loans Financing Receivable [Member] | Commercial Portfolio Segment [Member] | Substandard [Member]
Financing Receivable [Abstract]
Financing Receivable Commercial	2,469,000	3,633,000
Other Loans Financing Receivable [Member] | Commercial Portfolio Segment [Member] | Doubtful [Member]
Financing Receivable [Abstract]
Financing Receivable Commercial	553,000	146,000
Commercial Portfolio Segment [Member]
Financing Receivable [Abstract]
Financing Receivable Commercial	3,866,734,000	3,990,244,000
Commercial Portfolio Segment [Member] | Pass [Member]
Financing Receivable [Abstract]
Financing Receivable Commercial	3,479,075,000	3,544,306,000
Commercial Portfolio Segment [Member] | Special Mention [Member]
Financing Receivable [Abstract]
Financing Receivable Commercial	72,538,000	88,129,000
Commercial Portfolio Segment [Member] | Substandard [Member]
Financing Receivable [Abstract]
Financing Receivable Commercial	313,043,000	355,078,000
Commercial Portfolio Segment [Member] | Doubtful [Member]
Financing Receivable [Abstract]
Financing Receivable Commercial	2,078,000	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	49,668,000	53,797,000
Past Due 30 - 89 Days	490,000	223,000
Past Due Greater Than 90 Days	176,000
Nonaccrual	1,762,000	2,535,000
Subtotal	52,096,000	56,555,000
Real Estate Secured Financing Receivable [Member] | Residential Financing Receivable [Member] | Consumer Portfolio Segment [Member]
Financing Receivable Aging [Abstract]
Current	1,551,510,000	1,559,611,000
Past Due 30 - 89 Days	11,346,000	10,302,000
Past Due Greater Than 90 Days	1,742,000	1,278,000
Nonaccrual	17,182,000	20,916,000
Subtotal	1,581,780,000	1,592,107,000
Real Estate Secured Financing Receivable [Member] | Nonresidential Properties Financing Receivables [Member] | Consumer Portfolio Segment [Member]
Financing Receivable Aging [Abstract]
Current	876,000	975,000
Past Due 30 - 89 Days	37,000	0
Nonaccrual	0	0
Subtotal	913,000	975,000
Real Estate Secured Financing Receivable [Member] | Other Real Estate Secured Financing Receivable [Member] | Consumer Portfolio Segment [Member]
Financing Receivable Aging [Abstract]
Current	7,189,000	8,282,000
Past Due 30 - 89 Days	6,000	26,000
Nonaccrual	30,000	35,000
Subtotal	7,225,000	8,343,000
Commercial And Industrial Loans Financing Receivable [Member] | Consumer Portfolio Segment [Member]
Financing Receivable Aging [Abstract]
Current	2,327,000	5,075,000
Past Due 30 - 89 Days	52,000	97,000
Nonaccrual	24,000	39,000
Subtotal	2,403,000	5,211,000
Consumer Loans Financing Receivable [Member] | Consumer Portfolio Segment [Member]
Financing Receivable Aging [Abstract]
Current	258,724,000	383,529,000
Past Due 30 - 89 Days	6,973,000	13,741,000
Past Due Greater Than 90 Days	579,000	2,260,000
Nonaccrual	906,000	2,111,000
Subtotal	267,182,000	401,641,000
Other Loans Financing Receivable [Member] | Consumer Portfolio Segment [Member]
Financing Receivable Aging [Abstract]
Current	5,348,000	5,166,000
Past Due 30 - 89 Days	31,000
Subtotal	5,379,000	5,166,000
Consumer Portfolio Segment [Member]
Financing Receivable Aging [Abstract]
Current	1,875,642,000	2,016,435,000
Past Due 30 - 89 Days	18,935,000	24,389,000
Past Due Greater Than 90 Days	2,497,000	3,538,000
Nonaccrual	19,904,000	25,636,000
Subtotal	1,916,978,000	2,069,998,000
Real Estate Secured Financing Receivable [Member] | Construction Land Development And Other Financing Receivable [Member]
Financing Receivable Aging [Abstract]
Current	446,730,000	523,834,000
Past Due 30 - 89 Days	4,653,000	1,651,000
Nonaccrual	29,594,000	57,831,000
Total LHFI, Excluding Covered Loans	481,821,000	583,316,000
Real Estate Secured Financing Receivable [Member] | Residential Financing Receivable [Member]
Financing Receivable Aging [Abstract]
Current	1,679,267,000	1,688,811,000
Past Due 30 - 89 Days	12,798,000	11,654,000
Nonaccrual	23,558,000	30,313,000
Total LHFI, Excluding Covered Loans	1,717,366,000	1,732,056,000
Real Estate Secured Financing Receivable [Member] | Nonresidential Properties Financing Receivables [Member]
Financing Receivable Aging [Abstract]
Current	1,392,407,000	1,459,811,000
Past Due 30 - 89 Days	19,863,000	9,149,000
Nonaccrual	25,303,000	29,013,000
Total LHFI, Excluding Covered Loans	1,437,573,000	1,498,108,000
Real Estate Secured Financing Receivable [Member] | Other Real Estate Secured Financing Receivable [Member]
Financing Receivable Aging [Abstract]
Current	203,100,000	225,368,000
Past Due 30 - 89 Days	63,000	441,000
Nonaccrual	4,821,000	6,154,000
Total LHFI, Excluding Covered Loans	207,984,000	231,963,000
Commercial And Industrial Loans Financing Receivable [Member]
Financing Receivable Aging [Abstract]
Total LHFI, Excluding Covered Loans	1,083,753,000	1,068,369,000
Consumer Loans Financing Receivable [Member]
Financing Receivable Aging [Abstract]
Current	259,543,000	384,052,000
Past Due 30 - 89 Days	6,973,000	13,741,000
Nonaccrual	907,000	2,112,000
Total LHFI, Excluding Covered Loans	268,002,000	402,165,000
Other Loans Financing Receivable [Member]
Financing Receivable Aging [Abstract]
Current	585,237,000	542,805,000
Past Due 30 - 89 Days	785,000	67,000
Nonaccrual	1,191,000	1,393,000
Total LHFI, Excluding Covered Loans	587,213,000	544,265,000
Construction Land Development And Other Financing Receivable [Member]
Financing Receivable Aging [Abstract]
Total LHFI, Excluding Covered Loans	481,821,000	583,316,000
Residential Financing Receivable [Member]
Financing Receivable Aging [Abstract]
Total LHFI, Excluding Covered Loans	1,717,366,000	1,732,056,000
Nonresidential Properties Financing Receivables [Member]
Financing Receivable Aging [Abstract]
Total LHFI, Excluding Covered Loans	1,437,573,000	1,498,108,000
Other Real Estate Secured Financing Receivable [Member]
Financing Receivable Aging [Abstract]
Total LHFI, Excluding Covered Loans	$ 207,984,000	$ 231,963,000