Loans and Allowances for Credit Losses Part 3 (Details) (USD $)	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	$ 11,494,951,000		$ 10,789,740,000	$ 10,480,793,000
Non-Graded, Recorded Investment	1,931,907,000		2,002,524,000	1,959,989,000
Total	13,426,858,000		12,792,264,000	12,440,782,000
Related Allowance [Abstract]
Internally Risk Graded, Allowance	135,294,000		127,961,000	118,586,000
Non-Graded, Allowance	28,447,000		29,222,000	42,089,000
Allowance For Financing Receivable Total	190,690,000	188,318,000	185,396,000	203,124,000	205,965,000	215,507,000
Performing [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	11,334,373,000		10,650,784,000	10,303,771,000
Non-Graded, Recorded Investment	1,890,830,000		1,966,324,000	1,924,100,000
Potential Problem [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	104,975,000		74,007,000	90,778,000
Nonaccrual [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	55,603,000		64,949,000	86,244,000
Non-Graded, Recorded Investment	41,077,000		36,200,000	35,889,000
Commercial [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	8,341,114,000		7,888,219,000	7,689,954,000
Non-Graded, Recorded Investment	26,547,000		55,002,000	18,166,000
Total	8,367,661,000		7,943,221,000	7,708,120,000
Related Allowance [Abstract]
Internally Risk Graded, Allowance	86,893,000		78,250,000	62,830,000
Non-Graded, Allowance	913,000		930,000	1,214,000
Allowance For Financing Receivable Total	87,806,000		79,180,000	64,044,000
Commercial [Member] | Performing [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	8,258,262,000		7,841,108,000	7,624,152,000
Non-Graded, Recorded Investment	26,485,000		54,929,000	18,105,000
Commercial [Member] | Potential Problem [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	65,811,000		30,424,000	44,994,000
Commercial [Member] | Nonaccrual [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	17,041,000		16,687,000	20,808,000
Non-Graded, Recorded Investment	62,000		73,000	61,000
Energy [Member]
Recorded Investment [Abstract]
Total	2,419,788,000		2,351,760,000	2,384,746,000
Energy [Member] | Performing [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	2,395,942,000		2,347,519,000	2,378,187,000
Non-Graded, Recorded Investment	0		0	0
Energy [Member] | Potential Problem [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	22,227,000		2,381,000	4,282,000
Energy [Member] | Nonaccrual [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	1,619,000		1,860,000	2,277,000
Non-Graded, Recorded Investment	0		0	0
Services [Member]
Recorded Investment [Abstract]
Total	2,377,065,000		2,282,210,000	2,204,253,000
Services [Member] | Performing [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	2,352,450,000		2,265,984,000	2,170,695,000
Non-Graded, Recorded Investment	0		0	0
Services [Member] | Potential Problem [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	20,946,000		11,304,000	26,110,000
Services [Member] | Nonaccrual [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	3,669,000		4,922,000	7,448,000
Non-Graded, Recorded Investment	0		0	0
Wholesale/retail [Member]
Recorded Investment [Abstract]
Total	1,318,151,000		1,201,364,000	1,175,543,000
Wholesale/retail [Member] | Performing [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	1,307,426,000		1,191,791,000	1,167,215,000
Non-Graded, Recorded Investment	0		0	0
Wholesale/retail [Member] | Potential Problem [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	4,840,000		2,604,000	1,628,000
Wholesale/retail [Member] | Nonaccrual [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	5,885,000		6,969,000	6,700,000
Non-Graded, Recorded Investment	0		0	0
Manufacturing [Member]
Recorded Investment [Abstract]
Total	452,866,000		391,751,000	386,133,000
Manufacturing [Member] | Performing [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	442,493,000		381,794,000	381,729,000
Non-Graded, Recorded Investment	0		0	0
Manufacturing [Member] | Potential Problem [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	6,866,000		9,365,000	3,528,000
Manufacturing [Member] | Nonaccrual [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	3,507,000		592,000	876,000
Non-Graded, Recorded Investment	0		0	0
Healthcare [Member]
Recorded Investment [Abstract]
Total	1,394,156,000		1,274,246,000	1,118,810,000
Healthcare [Member] | Performing [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	1,385,395,000		1,272,626,000	1,116,089,000
Non-Graded, Recorded Investment	0		0	0
Healthcare [Member] | Potential Problem [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	7,339,000		34,000	51,000
Healthcare [Member] | Nonaccrual [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	1,422,000		1,586,000	2,670,000
Non-Graded, Recorded Investment	0		0	0
Other commercial and industrial [Member]
Recorded Investment [Abstract]
Total	405,635,000		441,890,000	438,635,000
Other commercial and industrial [Member] | Performing [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	374,556,000		381,394,000	410,237,000
Non-Graded, Recorded Investment	26,485,000		54,929,000	18,105,000
Other commercial and industrial [Member] | Potential Problem [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	3,593,000		4,736,000	9,395,000
Other commercial and industrial [Member] | Nonaccrual [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	939,000		758,000	837,000
Non-Graded, Recorded Investment	62,000		73,000	61,000
Commercial Real Estate [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	2,654,978,000		2,415,353,000	2,317,096,000
Non-Graded, Recorded Investment	0		0	0
Total	2,654,978,000		2,415,353,000	2,317,096,000
Related Allowance [Abstract]
Internally Risk Graded, Allowance	41,252,000		41,573,000	49,687,000
Non-Graded, Allowance	0		0	0
Allowance For Financing Receivable Total	41,252,000		41,573,000	49,687,000
Commercial Real Estate [Member] | Performing [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	2,583,554,000		2,334,998,000	2,218,338,000
Non-Graded, Recorded Investment	0		0	0
Commercial Real Estate [Member] | Potential Problem [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	36,952,000		39,505,000	40,065,000
Commercial Real Estate [Member] | Nonaccrual [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	34,472,000		40,850,000	58,693,000
Non-Graded, Recorded Investment	0		0	0
Residential construction and land development [Member]
Recorded Investment [Abstract]
Total	184,779,000		206,258,000	225,654,000
Residential construction and land development [Member] | Performing [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	152,228,000		173,488,000	184,216,000
Non-Graded, Recorded Investment	0		0	0
Residential construction and land development [Member] | Potential Problem [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	17,405,000		15,393,000	20,303,000
Residential construction and land development [Member] | Nonaccrual [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	15,146,000		17,377,000	21,135,000
Non-Graded, Recorded Investment	0		0	0
Retail [Member]
Recorded Investment [Abstract]
Total	642,110,000		586,047,000	553,412,000
Retail [Member] | Performing [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	636,332,000		579,506,000	540,872,000
Non-Graded, Recorded Investment	0		0	0
Retail [Member] | Potential Problem [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	1,579,000		1,684,000	4,134,000
Retail [Member] | Nonaccrual [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	4,199,000		4,857,000	8,406,000
Non-Graded, Recorded Investment	0		0	0
Office [Member]
Recorded Investment [Abstract]
Total	394,217,000		411,499,000	459,558,000
Office [Member] | Performing [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	389,487,000		403,951,000	450,790,000
Non-Graded, Recorded Investment	0		0	0
Office [Member] | Potential Problem [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	1,139,000		1,157,000	940,000
Office [Member] | Nonaccrual [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	3,591,000		6,391,000	7,828,000
Non-Graded, Recorded Investment	0		0	0
Multifamily [Member]
Recorded Investment [Abstract]
Total	677,403,000		576,502,000	500,452,000
Multifamily [Member] | Performing [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	663,349,000		562,800,000	491,864,000
Non-Graded, Recorded Investment	0		0	0
Multifamily [Member] | Potential Problem [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	14,054,000		13,695,000	2,141,000
Multifamily [Member] | Nonaccrual [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	0		7,000	6,447,000
Non-Graded, Recorded Investment	0		0	0
Industrial [Member]
Recorded Investment [Abstract]
Total	342,080,000		243,877,000	253,990,000
Industrial [Member] | Performing [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	341,449,000		243,625,000	253,732,000
Non-Graded, Recorded Investment	0		0	0
Industrial [Member] | Potential Problem [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	0		0	258,000
Industrial [Member] | Nonaccrual [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	631,000		252,000	0
Non-Graded, Recorded Investment	0		0	0
Other commercial real estate [Member]
Recorded Investment [Abstract]
Total	414,389,000		391,170,000	324,030,000
Other commercial real estate [Member] | Performing [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	400,709,000		371,628,000	296,864,000
Non-Graded, Recorded Investment	0		0	0
Other commercial real estate [Member] | Potential Problem [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	2,775,000		7,576,000	12,289,000
Other commercial real estate [Member] | Nonaccrual [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	10,905,000		11,966,000	14,877,000
Non-Graded, Recorded Investment	0		0	0
Residential Mortgage [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	203,097,000		220,635,000	230,359,000
Non-Graded, Recorded Investment	1,805,118,000		1,831,391,000	1,809,426,000
Total	2,008,215,000		2,052,026,000	2,039,785,000
Related Allowance [Abstract]
Internally Risk Graded, Allowance	4,169,000		5,481,000	3,753,000
Non-Graded, Allowance	23,485,000		23,984,000	35,453,000
Allowance For Financing Receivable Total	27,654,000		29,465,000	39,206,000
Residential Mortgage [Member] | Performing [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	197,005,000		210,142,000	219,222,000
Non-Graded, Recorded Investment	1,764,683,000		1,796,281,000	1,775,240,000
Residential Mortgage [Member] | Potential Problem [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	2,187,000		3,283,000	4,789,000
Residential Mortgage [Member] | Nonaccrual [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	3,905,000		7,210,000	6,348,000
Non-Graded, Recorded Investment	40,435,000		35,110,000	34,186,000
Permanent mortage [Member]
Recorded Investment [Abstract]
Total	1,020,928,000		1,062,744,000	1,095,871,000
Permanent mortage [Member] | Performing [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	197,005,000		210,142,000	219,222,000
Non-Graded, Recorded Investment	788,784,000		815,040,000	839,113,000
Permanent mortage [Member] | Potential Problem [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	2,187,000		3,283,000	4,789,000
Permanent mortage [Member] | Nonaccrual [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	3,905,000		7,210,000	6,348,000
Non-Graded, Recorded Investment	29,047,000		27,069,000	26,399,000
Permanent mortgages guaranteed by US govenment agencies [Member]
Recorded Investment [Abstract]
Total	188,087,000		181,598,000	156,887,000
Permanent mortgages guaranteed by US govenment agencies [Member] | Performing [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	0		0	0
Non-Graded, Recorded Investment	186,140,000		180,821,000	156,804,000
Permanent mortgages guaranteed by US govenment agencies [Member] | Potential Problem [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	0		0	0
Permanent mortgages guaranteed by US govenment agencies [Member] | Nonaccrual [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	0		0	0
Non-Graded, Recorded Investment	1,947,000		777,000	83,000
Home equity {Member]
Recorded Investment [Abstract]
Total	799,200,000		807,684,000	787,027,000
Home equity {Member] | Performing [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	0		0	0
Non-Graded, Recorded Investment	789,759,000		800,420,000	779,323,000
Home equity {Member] | Potential Problem [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	0		0	0
Home equity {Member] | Nonaccrual [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	0		0	0
Non-Graded, Recorded Investment	9,441,000		7,264,000	7,704,000
Consumer [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	295,762,000		265,533,000	243,384,000
Non-Graded, Recorded Investment	100,242,000		116,131,000	132,397,000
Total	396,004,000		381,664,000	375,781,000
Related Allowance [Abstract]
Internally Risk Graded, Allowance	2,980,000		2,657,000	2,316,000
Non-Graded, Allowance	4,049,000		4,308,000	5,422,000
Allowance For Financing Receivable Total	7,029,000		6,965,000	7,738,000
Consumer [Member] | Performing [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	295,552,000		264,536,000	242,059,000
Non-Graded, Recorded Investment	99,662,000		115,114,000	130,755,000
Consumer [Member] | Potential Problem [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	25,000		795,000	930,000
Consumer [Member] | Nonaccrual [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	185,000		202,000	395,000
Non-Graded, Recorded Investment	580,000		1,017,000	1,642,000
Specific Allowance [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	11,494,951,000		10,789,740,000	10,480,793,000
Non-Graded, Recorded Investment	1,931,907,000		2,002,524,000	1,959,989,000
Total	13,426,858,000		12,792,264,000	12,440,782,000
Related Allowance [Abstract]
Internally Risk Graded, Allowance	135,294,000		127,961,000	118,586,000
Non-Graded, Allowance	28,447,000		29,222,000	42,089,000
Allowance For Financing Receivable Total	163,741,000		157,183,000	160,675,000
Nonspecific Allowance [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	$ 26,949,000	$ 26,965,000	$ 28,213,000	$ 42,449,000	$ 42,812,000	$ 44,187,000