Loans and Allowances for Credit Losses Part 7 (Details) (USD $)	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2013
Financing receivable, recorded investment, aging [Abstract]
Current	$ 12,799,061,000	$ 12,509,986,000	$ 11,799,899,000
Past due 30 to 89 days	36,309,000	38,099,000	38,182,000
Past due 90 days or more	137,778,000	143,030,000	122,850,000
Nonaccrual	104,706,000	101,149,000	132,633,000
Total	13,077,854,000	12,792,264,000	12,093,564,000
Commercial [Member]
Financing receivable, recorded investment, aging [Abstract]
Current	8,027,248,000	7,922,000,000	7,390,259,000
Past due 30 to 89 days	5,411,000	4,112,000	7,604,000
Past due 90 days or more	0	349,000	581,000
Nonaccrual	19,047,000	16,760,000	19,861,000
Total	8,051,706,000	7,943,221,000	7,418,305,000
Energy [Member]
Financing receivable, recorded investment, aging [Abstract]
Current	2,341,923,000	2,347,267,000	2,346,530,000
Past due 30 to 89 days	390,000	2,483,000	525,000
Past due 90 days or more	0	150,000	0
Nonaccrual	1,759,000	1,860,000	2,377,000
Total	2,344,072,000	2,351,760,000	2,349,432,000
Services [Member]
Financing receivable, recorded investment, aging [Abstract]
Current	2,227,008,000	2,276,036,000	2,103,111,000
Past due 30 to 89 days	882,000	1,210,000	1,697,000
Past due 90 days or more	0	42,000	517,000
Nonaccrual	4,581,000	4,922,000	9,474,000
Total	2,232,471,000	2,282,210,000	2,114,799,000
Wholesale/retail [Member]
Financing receivable, recorded investment, aging [Abstract]
Current	1,219,058,000	1,193,905,000	1,082,491,000
Past due 30 to 89 days	78,000	338,000	270,000
Past due 90 days or more	0	152,000	0
Nonaccrual	6,854,000	6,969,000	2,239,000
Total	1,225,990,000	1,201,364,000	1,085,000,000
Manufacturing [Member]
Financing receivable, recorded investment, aging [Abstract]
Current	437,707,000	391,159,000	397,746,000
Past due 30 to 89 days	2,943,000	0	224,000
Past due 90 days or more	0	0	0
Nonaccrual	3,565,000	592,000	1,848,000
Total	444,215,000	391,751,000	399,818,000
Healthcare [Member]
Financing receivable, recorded investment, aging [Abstract]
Current	1,394,479,000	1,272,660,000	1,073,804,000
Past due 30 to 89 days	640,000	0	4,806,000
Past due 90 days or more	0	0	64,000
Nonaccrual	1,443,000	1,586,000	2,962,000
Total	1,396,562,000	1,274,246,000	1,081,636,000
Integrated food services [Member]
Financing receivable, recorded investment, aging [Abstract]
Current	126,414,000	150,494,000	173,800,000
Past due 30 to 89 days	100,000	0	0
Past due 90 days or more	0	0	0
Nonaccrual	0	0	0
Total	126,514,000	150,494,000	173,800,000
Other commercial and industrial [Member]
Financing receivable, recorded investment, aging [Abstract]
Current	280,659,000	290,479,000	212,777,000
Past due 30 to 89 days	378,000	81,000	82,000
Past due 90 days or more	0	5,000	0
Nonaccrual	845,000	831,000	961,000
Total	281,882,000	291,396,000	213,820,000
Commercial Real Estate [Member]
Financing receivable, recorded investment, aging [Abstract]
Current	2,589,656,000	2,370,684,000	2,214,348,000
Past due 30 to 89 days	493,000	2,788,000	2,303,000
Past due 90 days or more	1,953,000	1,031,000	3,334,000
Nonaccrual	39,305,000	40,850,000	65,175,000
Total	2,631,407,000	2,415,353,000	2,285,160,000
Residential construction and land development [Member]
Financing receivable, recorded investment, aging [Abstract]
Current	168,043,000	188,434,000	214,367,000
Past due 30 to 89 days	230,000	428,000	0
Past due 90 days or more	0	19,000	0
Nonaccrual	16,547,000	17,377,000	23,462,000
Total	184,820,000	206,258,000	237,829,000
Retail [Member]
Financing receivable, recorded investment, aging [Abstract]
Current	634,497,000	580,926,000	575,239,000
Past due 30 to 89 days	0	264,000	119,000
Past due 90 days or more	1,383,000	0	0
Nonaccrual	4,626,000	4,857,000	8,921,000
Total	640,506,000	586,047,000	584,279,000
Office [Member]
Financing receivable, recorded investment, aging [Abstract]
Current	429,700,000	404,505,000	404,401,000
Past due 30 to 89 days	263,000	603,000	436,000
Past due 90 days or more	0	0	2,956,000
Nonaccrual	6,301,000	6,391,000	12,851,000
Total	436,264,000	411,499,000	420,644,000
Multifamily [Member]
Financing receivable, recorded investment, aging [Abstract]
Current	662,674,000	576,495,000	455,973,000
Past due 30 to 89 days	0	0	0
Past due 90 days or more	0	0	0
Nonaccrual	0	7,000	4,501,000
Total	662,674,000	576,502,000	460,474,000
Industrial [Member]
Financing receivable, recorded investment, aging [Abstract]
Current	304,321,000	243,625,000	234,851,000
Past due 30 to 89 days	0	0	0
Past due 90 days or more	0	0	0
Nonaccrual	886,000	252,000	2,198,000
Total	305,207,000	243,877,000	237,049,000
Other commercial real estate [Member]
Financing receivable, recorded investment, aging [Abstract]
Current	390,421,000	376,699,000	329,517,000
Past due 30 to 89 days	0	1,493,000	1,748,000
Past due 90 days or more	570,000	1,012,000	378,000
Nonaccrual	10,945,000	11,966,000	13,242,000
Total	401,936,000	391,170,000	344,885,000
Residential Mortgage [Member]
Financing receivable, recorded investment, aging [Abstract]
Current	1,807,639,000	1,837,885,000	1,822,322,000
Past due 30 to 89 days	29,832,000	30,172,000	26,081,000
Past due 90 days or more	135,824,000	141,649,000	118,621,000
Nonaccrual	45,380,000	42,320,000	45,426,000
Total	2,018,675,000	2,052,026,000	2,012,450,000
Permanent mortage [Member]
Financing receivable, recorded investment, aging [Abstract]
Current	991,486,000	1,018,670,000	1,047,648,000
Past due 30 to 89 days	5,732,000	9,795,000	5,774,000
Past due 90 days or more	12,000	0	0
Nonaccrual	36,342,000	34,279,000	38,153,000
Total	1,033,572,000	1,062,744,000	1,091,575,000
Permanent mortgages guaranteed by US govenment agencies [Member]
Financing receivable, recorded investment, aging [Abstract]
Current	26,919,000	21,916,000	25,915,000
Past due 30 to 89 days	20,544,000	17,290,000	17,669,000
Past due 90 days or more	135,787,000	141,615,000	118,621,000
Nonaccrual	1,572,000	777,000	214,000
Total	184,822,000	181,598,000	162,419,000
Home equity {Member]
Financing receivable, recorded investment, aging [Abstract]
Current	789,234,000	797,299,000	748,759,000
Past due 30 to 89 days	3,556,000	3,087,000	2,638,000
Past due 90 days or more	25,000	34,000	0
Nonaccrual	7,466,000	7,264,000	7,059,000
Total	800,281,000	807,684,000	758,456,000
Consumer [Member]
Financing receivable, recorded investment, aging [Abstract]
Current	374,518,000	379,417,000	372,970,000
Past due 30 to 89 days	573,000	1,027,000	2,194,000
Past due 90 days or more	1,000	1,000	314,000
Nonaccrual	974,000	1,219,000	2,171,000
Total	$ 376,066,000	$ 381,664,000	$ 377,649,000