Loans, Allowance for Loan Losses, and Credit Quality Loans by Past Due Status (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Summarized details of Loans
30-59 Days Past Due	$ 43,388	$ 63,973
60-89 Days Past Due	33,281	26,720
90 Days or More Past Due	86,863	134,445
Total Past Due	163,532	225,138
Current	15,732,729	15,185,884
Total loans	15,896,261	15,411,022
Commercial And Industrial Financing Receivable [Member]
Summarized details of Loans
30-59 Days Past Due	4,388	18,116
60-89 Days Past Due	5,200	2,573
90 Days or More Past Due	10,964	12,041
Total Past Due	20,552	32,730
Current	4,802,128	4,469,291
Total loans	4,822,680	4,502,021
Commercial Real Estate Owner Occupied Portfolio [Member]
Summarized details of Loans
30-59 Days Past Due	3,497	11,909
60-89 Days Past Due	3,815	2,382
90 Days or More Past Due	11,125	12,127
Total Past Due	18,437	26,418
Current	1,096,278	1,193,329
Total loans	1,114,715	1,219,747
Finance Leases Financing Receivable [Member]
Summarized details of Loans
30-59 Days Past Due	0	15
60-89 Days Past Due	0	12
90 Days or More Past Due	69	9
Total Past Due	69	36
Current	55,414	64,160
Total loans	55,483	64,196
Commercial And Business Lending [Member]
Summarized details of Loans
30-59 Days Past Due	7,885	30,040
60-89 Days Past Due	9,015	4,967
90 Days or More Past Due	22,158	24,177
Total Past Due	39,058	59,184
Current	5,953,820	5,726,780
Total loans	5,992,878	5,785,964
Commercial Real Estate Investor Portfolio Segment [Member]
Summarized details of Loans
30-59 Days Past Due	12,489	8,621
60-89 Days Past Due	15,033	8,120
90 Days or More Past Due	20,466	31,294
Total Past Due	47,988	48,035
Current	2,891,468	2,858,724
Total loans	2,939,456	2,906,759
Commercial Real Estate Construction Financing Receivable [Member]
Summarized details of Loans
30-59 Days Past Due	3,212	1,644
60-89 Days Past Due	1,118	1,527
90 Days or More Past Due	2,267	9,922
Total Past Due	6,597	13,093
Current	889,651	642,288
Total loans	896,248	655,381
Commercial Real Estate Lending [Member]
Summarized details of Loans
30-59 Days Past Due	15,701	10,265
60-89 Days Past Due	16,151	9,647
90 Days or More Past Due	22,733	41,216
Total Past Due	54,585	61,128
Current	3,781,119	3,501,012
Total loans	3,835,704	3,562,140
Commercial Financing Receivable [Member]
Summarized details of Loans
30-59 Days Past Due	23,586	40,305
60-89 Days Past Due	25,166	14,614
90 Days or More Past Due	44,891	65,393
Total Past Due	93,643	120,312
Current	9,734,939	9,227,792
Total loans	9,828,582	9,348,104
Home Equity [Member]
Summarized details of Loans
30-59 Days Past Due	10,336	11,607
60-89 Days Past Due	3,704	5,905
90 Days or More Past Due	14,677	28,570
Total Past Due	28,717	46,082
Current	1,796,297	2,173,412
Total loans	1,825,014	2,219,494
Installment [Member]
Summarized details of Loans
30-59 Days Past Due	1,014	1,453
60-89 Days Past Due	289	950
90 Days or More Past Due	926	1,599
Total Past Due	2,229	4,002
Current	404,845	462,725
Total loans	407,074	466,727
Residential, Prime, Financing Receivable [Member]
Summarized details of Loans
30-59 Days Past Due	8,452	10,608
60-89 Days Past Due	4,122	5,251
90 Days or More Past Due	26,369	38,883
Total Past Due	38,943	54,742
Current	3,796,648	3,321,955
Total loans	3,835,591	3,376,697
Consumer Loan [Member]
Summarized details of Loans
30-59 Days Past Due	19,802	23,668
60-89 Days Past Due	8,115	12,106
90 Days or More Past Due	41,972	69,052
Total Past Due	69,889	104,826
Current	5,997,790	5,958,092
Total loans	6,067,679	6,062,918
Accruing Loans [Member]
Summarized details of Loans
30-59 Days Past Due	29,071	49,953
60-89 Days Past Due	23,978	14,128
90 Days or More Past Due	2,350	2,289
Total Past Due	55,399	66,370
Current	15,655,434	15,091,784
Total loans	15,710,833	15,158,154
Accruing Loans [Member] | Commercial And Industrial Financing Receivable [Member]
Summarized details of Loans
30-59 Days Past Due	3,390	9,557
60-89 Days Past Due	3,436	1,782
90 Days or More Past Due	1,199	79
Total Past Due	8,025	11,418
Current	4,776,936	4,451,421
Total loans	4,784,961	4,462,839
Accruing Loans [Member] | Commercial Real Estate Owner Occupied Portfolio [Member]
Summarized details of Loans
30-59 Days Past Due	1,015	10,420
60-89 Days Past Due	2,091	633
90 Days or More Past Due	0	308
Total Past Due	3,106	11,361
Current	1,081,945	1,184,132
Total loans	1,085,051	1,195,493
Accruing Loans [Member] | Finance Leases Financing Receivable [Member]
Summarized details of Loans
30-59 Days Past Due	0	0
60-89 Days Past Due	0	12
90 Days or More Past Due	0	0
Total Past Due	0	12
Current	55,414	61,153
Total loans	55,414	61,165
Accruing Loans [Member] | Commercial And Business Lending [Member]
Summarized details of Loans
30-59 Days Past Due	4,405	19,977
60-89 Days Past Due	5,527	2,427
90 Days or More Past Due	1,199	387
Total Past Due	11,131	22,791
Current	5,914,295	5,696,706
Total loans	5,925,426	5,719,497
Accruing Loans [Member] | Commercial Real Estate Investor Portfolio Segment [Member]
Summarized details of Loans
30-59 Days Past Due	9,081	8,424
60-89 Days Past Due	14,134	5,048
90 Days or More Past Due	0	366
Total Past Due	23,215	13,838
Current	2,878,645	2,834,234
Total loans	2,901,860	2,848,072
Accruing Loans [Member] | Commercial Real Estate Construction Financing Receivable [Member]
Summarized details of Loans
30-59 Days Past Due	836	1,628
60-89 Days Past Due	1,118	1,527
90 Days or More Past Due	0	283
Total Past Due	1,954	3,438
Current	887,827	624,641
Total loans	889,781	628,079
Accruing Loans [Member] | Commercial Real Estate Lending [Member]
Summarized details of Loans
30-59 Days Past Due	9,917	10,052
60-89 Days Past Due	15,252	6,575
90 Days or More Past Due	0	649
Total Past Due	25,169	17,276
Current	3,766,472	3,458,875
Total loans	3,791,641	3,476,151
Accruing Loans [Member] | Commercial Financing Receivable [Member]
Summarized details of Loans
30-59 Days Past Due	14,322	30,029
60-89 Days Past Due	20,779	9,002
90 Days or More Past Due	1,199	1,036
Total Past Due	36,300	40,067
Current	9,680,767	9,155,581
Total loans	9,717,067	9,195,648
Accruing Loans [Member] | Home Equity [Member]
Summarized details of Loans
30-59 Days Past Due	8,611	10,151
60-89 Days Past Due	2,069	3,387
90 Days or More Past Due	346	96
Total Past Due	11,026	13,634
Current	1,788,821	2,166,645
Total loans	1,799,847	2,180,279
Accruing Loans [Member] | Installment [Member]
Summarized details of Loans
30-59 Days Past Due	885	1,300
60-89 Days Past Due	265	809
90 Days or More Past Due	637	1,013
Total Past Due	1,787	3,122
Current	404,173	461,767
Total loans	405,960	464,889
Accruing Loans [Member] | Residential, Prime, Financing Receivable [Member]
Summarized details of Loans
30-59 Days Past Due	5,253	8,473
60-89 Days Past Due	865	930
90 Days or More Past Due	168	144
Total Past Due	6,286	9,547
Current	3,781,673	3,307,791
Total loans	3,787,959	3,317,338
Accruing Loans [Member] | Consumer Loan [Member]
Summarized details of Loans
30-59 Days Past Due	14,749	19,924
60-89 Days Past Due	3,199	5,126
90 Days or More Past Due	1,151	1,253
Total Past Due	19,099	26,303
Current	5,974,667	5,936,203
Total loans	5,993,766	5,962,506
Nonaccrual Loan [Member]
Summarized details of Loans
30-59 Days Past Due	14,317	14,020
60-89 Days Past Due	9,303	12,592
90 Days or More Past Due	84,513	132,156
Total Past Due	108,133	158,768
Current	77,295	94,100
Total loans	185,428	252,868
Nonaccrual Loan [Member] | Commercial And Industrial Financing Receivable [Member]
Summarized details of Loans
30-59 Days Past Due	998	8,559
60-89 Days Past Due	1,764	791
90 Days or More Past Due	9,765	11,962
Total Past Due	12,527	21,312
Current	25,192	17,870
Total loans	37,719	39,182
Nonaccrual Loan [Member] | Commercial Real Estate Owner Occupied Portfolio [Member]
Summarized details of Loans
30-59 Days Past Due	2,482	1,489
60-89 Days Past Due	1,724	1,749
90 Days or More Past Due	11,125	11,819
Total Past Due	15,331	15,057
Current	14,333	9,197
Total loans	29,664	24,254
Nonaccrual Loan [Member] | Finance Leases Financing Receivable [Member]
Summarized details of Loans
30-59 Days Past Due	0	15
60-89 Days Past Due	0	0
90 Days or More Past Due	69	9
Total Past Due	69	24
Current	0	3,007
Total loans	69	3,031
Nonaccrual Loan [Member] | Commercial And Business Lending [Member]
Summarized details of Loans
30-59 Days Past Due	3,480	10,063
60-89 Days Past Due	3,488	2,540
90 Days or More Past Due	20,959	23,790
Total Past Due	27,927	36,393
Current	39,525	30,074
Total loans	67,452	66,467
Nonaccrual Loan [Member] | Commercial Real Estate Investor Portfolio Segment [Member]
Summarized details of Loans
30-59 Days Past Due	3,408	197
60-89 Days Past Due	899	3,072
90 Days or More Past Due	20,466	30,928
Total Past Due	24,773	34,197
Current	12,823	24,490
Total loans	37,596	58,687
Nonaccrual Loan [Member] | Commercial Real Estate Construction Financing Receivable [Member]
Summarized details of Loans
30-59 Days Past Due	2,376	16
60-89 Days Past Due	0	0
90 Days or More Past Due	2,267	9,639
Total Past Due	4,643	9,655
Current	1,824	17,647
Total loans	6,467	27,302
Nonaccrual Loan [Member] | Commercial Real Estate Lending [Member]
Summarized details of Loans
30-59 Days Past Due	5,784	213
60-89 Days Past Due	899	3,072
90 Days or More Past Due	22,733	40,567
Total Past Due	29,416	43,852
Current	14,647	42,137
Total loans	44,063	85,989
Nonaccrual Loan [Member] | Commercial Financing Receivable [Member]
Summarized details of Loans
30-59 Days Past Due	9,264	10,276
60-89 Days Past Due	4,387	5,612
90 Days or More Past Due	43,692	64,357
Total Past Due	57,343	80,245
Current	54,172	72,211
Total loans	111,515	152,456
Nonaccrual Loan [Member] | Home Equity [Member]
Summarized details of Loans
30-59 Days Past Due	1,725	1,456
60-89 Days Past Due	1,635	2,518
90 Days or More Past Due	14,331	28,474
Total Past Due	17,691	32,448
Current	7,476	6,767
Total loans	25,167	39,215
Nonaccrual Loan [Member] | Installment [Member]
Summarized details of Loans
30-59 Days Past Due	129	153
60-89 Days Past Due	24	141
90 Days or More Past Due	289	586
Total Past Due	442	880
Current	672	958
Total loans	1,114	1,838
Nonaccrual Loan [Member] | Residential, Prime, Financing Receivable [Member]
Summarized details of Loans
30-59 Days Past Due	3,199	2,135
60-89 Days Past Due	3,257	4,321
90 Days or More Past Due	26,201	38,739
Total Past Due	32,657	45,195
Current	14,975	14,164
Total loans	47,632	59,359
Nonaccrual Loan [Member] | Consumer Loan [Member]
Summarized details of Loans
30-59 Days Past Due	5,053	3,744
60-89 Days Past Due	4,916	6,980
90 Days or More Past Due	40,821	67,799
Total Past Due	50,790	78,523
Current	23,123	21,889
Total loans	$ 73,913	$ 100,412