Loans Part 3 (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	$ 9,645,217		$ 9,362,898	$ 8,914,817
Non-Graded, Recorded Investment	1,931,214		1,906,845	1,822,727
Total	11,576,431		11,269,743	10,737,544
Related Allowance [Abstract]
Internally Risk Graded, Allowance	147,045		160,086	212,930
Non-Graded, Allowance	43,766		47,045	46,556
Allowance For Financing Receivable Total	231,669	244,209	253,481	286,611	289,549	292,971
Performing [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	9,359,478		9,025,862	8,567,108
Non-Graded, Recorded Investment	1,913,049		1,882,048	1,798,967
Potential Problem [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	159,422		160,547	171,299
Nonaccrual [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	126,317		176,489	176,331
Non-Graded, Recorded Investment	18,165		24,797	23,839
Commercial [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	7,034,934		6,536,602	6,151,384
Non-Graded, Recorded Investment	17,610		18,468	18,861
Total	7,052,544		6,555,070	6,170,245
Related Allowance [Abstract]
Internally Risk Graded, Allowance	82,357		82,263	111,392
Non-Graded, Allowance	1,120		1,180	2,179
Allowance For Financing Receivable Total	83,477		83,443	113,571
Commercial [Member] | Performing [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	6,925,797		6,394,362	6,008,620
Non-Graded, Recorded Investment	17,510		18,416	18,658
Commercial [Member] | Potential Problem [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	74,708		73,481	89,602
Commercial [Member] | Nonaccrual [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	34,429		68,759	53,162
Non-Graded, Recorded Investment	100		52	203
Commercial [Member] | Energy [Member]
Recorded Investment [Abstract]
Total	2,278,336		2,005,041	1,710,106
Commercial [Member] | Energy [Member] | Performing [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	2,264,290		2,003,288	1,705,073
Non-Graded, Recorded Investment	0		0	0
Commercial [Member] | Energy [Member] | Potential Problem [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	10,959		1,417	4,688
Commercial [Member] | Energy [Member] | Nonaccrual [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	3,087		336	345
Non-Graded, Recorded Investment	0		0	0
Commercial [Member] | Services [Member]
Recorded Investment [Abstract]
Total	1,931,520		1,761,538	1,725,289
Commercial [Member] | Services [Member] | Performing [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	1,881,143		1,713,232	1,675,545
Non-Graded, Recorded Investment	0		0	0
Commercial [Member] | Services [Member] | Potential Problem [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	40,254		31,338	33,490
Commercial [Member] | Services [Member] | Nonaccrual [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	10,123		16,968	16,254
Non-Graded, Recorded Investment	0		0	0
Commercial [Member] | Wholesale/Retail [Member]
Recorded Investment [Abstract]
Total	960,184		967,426	1,054,149
Commercial [Member] | Wholesale/Retail [Member] | Performing [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	944,412		912,090	988,076
Non-Graded, Recorded Investment	0		0	0
Commercial [Member] | Wholesale/Retail [Member] | Potential Problem [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	11,597		34,156	40,935
Commercial [Member] | Wholesale/Retail [Member] | Nonaccrual [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	4,175		21,180	25,138
Non-Graded, Recorded Investment	0		0	0
Commercial [Member] | Manufacturing [Member]
Recorded Investment [Abstract]
Total	362,877		336,733	367,414
Commercial [Member] | Manufacturing [Member] | Performing [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	340,815		311,292	360,221
Non-Graded, Recorded Investment	0		0	0
Commercial [Member] | Manufacturing [Member] | Potential Problem [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	9,832		2,390	2,827
Commercial [Member] | Manufacturing [Member] | Nonaccrual [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	12,230		23,051	4,366
Non-Graded, Recorded Investment	0		0	0
Commercial [Member] | Healthcare [Member]
Recorded Investment [Abstract]
Total	1,009,128		978,160	855,744
Commercial [Member] | Healthcare [Member] | Performing [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	1,004,773		969,260	846,790
Non-Graded, Recorded Investment	0		0	0
Commercial [Member] | Healthcare [Member] | Potential Problem [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	1,045		3,414	2,992
Commercial [Member] | Healthcare [Member] | Nonaccrual [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	3,310		5,486	5,962
Non-Graded, Recorded Investment	0		0	0
Commercial [Member] | Integrated Food Services [Member]
Recorded Investment [Abstract]
Total	216,978		204,311	187,833
Commercial [Member] | Integrated Food Services [Member] | Performing [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	216,282		203,555	186,573
Non-Graded, Recorded Investment	0		0	0
Commercial [Member] | Integrated Food Services [Member] | Potential Problem [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	696		756	1,260
Commercial [Member] | Integrated Food Services [Member] | Nonaccrual [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	0		0	0
Non-Graded, Recorded Investment	0		0	0
Commercial [Member] | Other Commercial and Industrial [Member]
Recorded Investment [Abstract]
Total	293,521		301,861	269,710
Commercial [Member] | Other Commercial and Industrial [Member] | Performing [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	274,082		281,645	246,342
Non-Graded, Recorded Investment	17,510		18,416	18,658
Commercial [Member] | Other Commercial and Industrial [Member] | Potential Problem [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	325		10	3,410
Commercial [Member] | Other Commercial and Industrial [Member] | Nonaccrual [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	1,504		1,738	1,097
Non-Graded, Recorded Investment	100		52	203
Commercial Real Estate [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	2,126,208		2,291,303	2,188,031
Non-Graded, Recorded Investment	6		0	0
Total	2,126,214		2,291,303	2,188,031
Related Allowance [Abstract]
Internally Risk Graded, Allowance	55,806		67,034	91,750
Non-Graded, Allowance	0		0	0
Allowance For Financing Receivable Total	55,806		67,034	91,750
Commercial Real Estate [Member] | Performing [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	1,977,737		2,124,872	2,012,968
Non-Graded, Recorded Investment	0		0	0
Commercial Real Estate [Member] | Potential Problem [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	68,263		67,238	64,700
Commercial Real Estate [Member] | Nonaccrual [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	80,208		99,193	110,363
Non-Graded, Recorded Investment	6		0	0
Commercial Real Estate [Member] | Construction and Land Development [Member]
Recorded Investment [Abstract]
Total	287,059		342,054	372,225
Commercial Real Estate [Member] | Construction and Land Development [Member] | Performing [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	214,263		252,936	280,210
Non-Graded, Recorded Investment	0		0	0
Commercial Real Estate [Member] | Construction and Land Development [Member] | Potential Problem [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	26,746		27,244	15,750
Commercial Real Estate [Member] | Construction and Land Development [Member] | Nonaccrual [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	46,050		61,874	76,265
Non-Graded, Recorded Investment	0		0	0
Commercial Real Estate [Member] | Retail [Member]
Recorded Investment [Abstract]
Total	492,377		509,402	449,784
Commercial Real Estate [Member] | Retail [Member] | Performing [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	476,179		499,295	438,129
Non-Graded, Recorded Investment	0		0	0
Commercial Real Estate [Member] | Retail [Member] | Potential Problem [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	8,290		3,244	7,013
Commercial Real Estate [Member] | Retail [Member] | Nonaccrual [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	7,908		6,863	4,642
Non-Graded, Recorded Investment	0		0	0
Commercial Real Estate [Member] | Office [Member]
Recorded Investment [Abstract]
Total	384,392		405,923	485,731
Commercial Real Estate [Member] | Office [Member] | Performing [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	361,451		381,918	459,507
Non-Graded, Recorded Investment	0		0	0
Commercial Real Estate [Member] | Office [Member] | Potential Problem [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	12,352		12,548	14,751
Commercial Real Estate [Member] | Office [Member] | Nonaccrual [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	10,589		11,457	11,473
Non-Graded, Recorded Investment	0		0	0
Commercial Real Estate [Member] | Multifamily [Member]
Recorded Investment [Abstract]
Total	362,165		369,028	334,541
Commercial Real Estate [Member] | Multifamily [Member] | Performing [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	352,269		357,436	323,964
Non-Graded, Recorded Investment	0		0	0
Commercial Real Estate [Member] | Multifamily [Member] | Potential Problem [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	6,677		8,079	5,860
Commercial Real Estate [Member] | Multifamily [Member] | Nonaccrual [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	3,219		3,513	4,717
Non-Graded, Recorded Investment	0		0	0
Commercial Real Estate [Member] | Industrial [Member]
Recorded Investment [Abstract]
Total	231,033		278,186	159,806
Commercial Real Estate [Member] | Industrial [Member] | Performing [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	230,760		277,906	159,518
Non-Graded, Recorded Investment	0		0	0
Commercial Real Estate [Member] | Industrial [Member] | Potential Problem [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	273		280	288
Commercial Real Estate [Member] | Industrial [Member] | Nonaccrual [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	0		0	0
Non-Graded, Recorded Investment	0		0	0
Commercial Real Estate [Member] | Other Commercial Real Estate [Member]
Recorded Investment [Abstract]
Total	369,188		386,710	385,944
Commercial Real Estate [Member] | Other Commercial Real Estate [Member] | Performing [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	342,815		355,381	351,640
Non-Graded, Recorded Investment	0		0	0
Commercial Real Estate [Member] | Other Commercial Real Estate [Member] | Potential Problem [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	13,925		15,843	21,038
Commercial Real Estate [Member] | Other Commercial Real Estate [Member] | Nonaccrual [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	12,442		15,486	13,266
Non-Graded, Recorded Investment	6		0	0
Residential Mortgage [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	283,031		317,798	355,102
Non-Graded, Recorded Investment	1,722,066		1,656,729	1,516,852
Total	2,005,097		1,974,527	1,871,954
Related Allowance [Abstract]
Internally Risk Graded, Allowance	6,987		8,262	7,911
Non-Graded, Allowance	35,701		38,214	37,332
Allowance For Financing Receivable Total	42,688		46,476	45,243
Residential Mortgage [Member] | Performing [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	262,423		294,478	330,464
Non-Graded, Recorded Investment	1,706,549		1,634,403	1,496,045
Residential Mortgage [Member] | Potential Problem [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	13,398		15,879	13,752
Residential Mortgage [Member] | Nonaccrual [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	7,210		7,441	10,885
Non-Graded, Recorded Investment	15,517		22,326	20,808
Residential Mortgage [Member] | Permanent Residential Mortgage [Member]
Recorded Investment [Abstract]
Total	1,141,371		1,153,644	1,155,291
Residential Mortgage [Member] | Permanent Residential Mortgage [Member] | Performing [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	262,423		294,478	330,464
Non-Graded, Recorded Investment	847,414		817,921	783,084
Residential Mortgage [Member] | Permanent Residential Mortgage [Member] | Potential Problem [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	13,398		15,879	13,752
Residential Mortgage [Member] | Permanent Residential Mortgage [Member] | Nonaccrual [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	7,210		7,441	10,885
Non-Graded, Recorded Investment	10,926		17,925	17,106
Residential Mortgage [Member] | Permanent Mortgages Guaranteed by US Government Agencies [Member]
Recorded Investment [Abstract]
Total	168,059		188,462	134,458
Residential Mortgage [Member] | Permanent Mortgages Guaranteed by US Government Agencies [Member] | Performing [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	0		0	0
Non-Graded, Recorded Investment	168,059		188,462	134,458
Residential Mortgage [Member] | Permanent Mortgages Guaranteed by US Government Agencies [Member] | Potential Problem [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	0		0	0
Residential Mortgage [Member] | Permanent Mortgages Guaranteed by US Government Agencies [Member] | Nonaccrual [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	0		0	0
Non-Graded, Recorded Investment	0		0	0
Residential Mortgage [Member] | Home Equity [Member]
Recorded Investment [Abstract]
Total	695,667		632,421	582,205
Residential Mortgage [Member] | Home Equity [Member] | Performing [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	0		0	0
Non-Graded, Recorded Investment	691,076		628,020	578,503
Residential Mortgage [Member] | Home Equity [Member] | Potential Problem [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	0		0	0
Residential Mortgage [Member] | Home Equity [Member] | Nonaccrual [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	0		0	0
Non-Graded, Recorded Investment	4,591		4,401	3,702
Consumer [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	201,044		217,195	220,300
Non-Graded, Recorded Investment	191,532		231,648	287,014
Total	392,576		448,843	507,314
Related Allowance [Abstract]
Internally Risk Graded, Allowance	1,895		2,527	1,877
Non-Graded, Allowance	6,945		7,651	7,045
Allowance For Financing Receivable Total	8,840		10,178	8,922
Consumer [Member] | Performing [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	193,521		212,150	215,056
Non-Graded, Recorded Investment	188,990		229,229	284,264
Consumer [Member] | Potential Problem [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	3,053		3,949	3,245
Consumer [Member] | Nonaccrual [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	4,470		1,096	1,921
Non-Graded, Recorded Investment	2,542		2,419	2,828
Consumer [Member] | Indirect Automobile [Member]
Recorded Investment [Abstract]
Total	62,924		105,149	162,500
Consumer [Member] | Indirect Automobile [Member] | Performing [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	0		0	0
Non-Graded, Recorded Investment	60,667		102,955	159,771
Consumer [Member] | Indirect Automobile [Member] | Potential Problem [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	0		0	0
Consumer [Member] | Indirect Automobile [Member] | Nonaccrual [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	0		0	0
Non-Graded, Recorded Investment	2,257		2,194	2,729
Consumer [Member] | Other Consumer [Member]
Recorded Investment [Abstract]
Total	329,652		343,694	344,814
Consumer [Member] | Other Consumer [Member] | Performing [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	193,521		212,150	215,056
Non-Graded, Recorded Investment	128,323		126,274	124,493
Consumer [Member] | Other Consumer [Member] | Potential Problem [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	3,053		3,949	3,245
Consumer [Member] | Other Consumer [Member] | Nonaccrual [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	4,470		1,096	1,921
Non-Graded, Recorded Investment	285		225	99
Allocated Class of Receivables [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	9,645,217		9,362,898	8,914,817
Non-Graded, Recorded Investment	1,931,214		1,906,845	1,822,727
Total	11,576,431		11,269,743	10,737,544
Related Allowance [Abstract]
Internally Risk Graded, Allowance	147,045		160,086	212,930
Non-Graded, Allowance	43,766		47,045	46,556
Allowance For Financing Receivable Total	190,811		207,131	259,486
Unallocated Financing Receivables [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	0		0	0
Non-Graded, Recorded Investment	0		0	0
Total	0		0	0
Related Allowance [Abstract]
Internally Risk Graded, Allowance	0		0	0
Non-Graded, Allowance	0		0	0
Allowance For Financing Receivable Total	$ 40,858		$ 46,350	$ 27,125