Loans, Allowance for Loan Losses, and Credit Quality (Details 6) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
Summarized details of Loans
30-59 Days Past Due	$ 60,972	$ 46,612
60-89 Days Past Due	27,238	29,844
90 Days or More Past Due	164,828	175,181
Total Past Due	253,038	251,637
Current	14,000,687	13,779,434
Total loans	14,253,725	14,031,071
Commercial and industrial financing receivable [Member]
Summarized details of Loans
30-59 Days Past Due	16,713	8,887
60-89 Days Past Due	3,052	12,163
90 Days or More Past Due	24,362	24,547
Total Past Due	44,127	45,597
Current	3,674,889	3,679,139
Total loans	3,719,016	3,724,736
Commercial Real Estate Owner Occupied Portfolio Segment
Summarized details of Loans
30-59 Days Past Due	5,087	8,978
60-89 Days Past Due	4,193	489
90 Days or More Past Due	17,534	19,724
Total Past Due	26,814	29,191
Current	1,047,941	1,057,638
Total loans	1,074,755	1,086,829
Finance Leases Financing Receivable [Member]
Summarized details of Loans
30-59 Days Past Due	11	31
60-89 Days Past Due	44	73
90 Days or More Past Due	843	858
Total Past Due	898	962
Current	60,310	57,232
Total loans	61,208	58,194
Commercial and business lending
Summarized details of Loans
30-59 Days Past Due	21,811	17,896
60-89 Days Past Due	7,289	12,725
90 Days or More Past Due	42,739	45,129
Total Past Due	71,839	75,750
Current	4,783,140	4,794,009
Total loans	4,854,979	4,869,759
Commercial Real Estate Investor Portfolio Segment
Summarized details of Loans
30-59 Days Past Due	6,885	5,102
60-89 Days Past Due	5,604	4,930
90 Days or More Past Due	29,748	31,529
Total Past Due	42,237	41,561
Current	2,622,014	2,522,206
Total loans	2,664,251	2,563,767
Real estate construction
Summarized details of Loans
30-59 Days Past Due	1,736	909
60-89 Days Past Due	238	605
90 Days or More Past Due	17,661	19,106
Total Past Due	19,635	20,620
Current	546,318	563,426
Total loans	565,953	584,046
Commercial real estate lending
Summarized details of Loans
30-59 Days Past Due	8,621	6,011
60-89 Days Past Due	5,842	5,535
90 Days or More Past Due	47,409	50,635
Total Past Due	61,872	62,181
Current	3,168,332	3,085,632
Total loans	3,230,204	3,147,813
Total commercial [Member]
Summarized details of Loans
30-59 Days Past Due	30,432	23,907
60-89 Days Past Due	13,131	18,260
90 Days or More Past Due	90,148	95,764
Total Past Due	133,711	137,931
Current	7,951,472	7,879,641
Total loans	8,085,183	8,017,572
Home Equity [Member]
Summarized details of Loans
30-59 Days Past Due	15,750	12,217
60-89 Days Past Due	8,863	5,198
90 Days or More Past Due	30,482	34,976
Total Past Due	55,095	52,391
Current	2,446,675	2,452,313
Total loans	2,501,770	2,504,704
Installment
Summarized details of Loans
30-59 Days Past Due	2,689	2,187
60-89 Days Past Due	679	1,181
90 Days or More Past Due	1,471	1,288
Total Past Due	4,839	4,656
Current	532,789	553,126
Total loans	537,628	557,782
Total retail [Member]
Summarized details of Loans
30-59 Days Past Due	18,439	14,404
60-89 Days Past Due	9,542	6,379
90 Days or More Past Due	31,953	36,264
Total Past Due	59,934	57,047
Current	2,979,464	3,005,439
Total loans	3,039,398	3,062,486
Residential mortgage [Member]
Summarized details of Loans
30-59 Days Past Due	12,101	8,301
60-89 Days Past Due	4,565	5,205
90 Days or More Past Due	42,727	43,153
Total Past Due	59,393	56,659
Current	3,069,751	2,894,354
Total loans	3,129,144	2,951,013
Consumer Loan [Member]
Summarized details of Loans
30-59 Days Past Due	30,540	22,705
60-89 Days Past Due	14,107	11,584
90 Days or More Past Due	74,680	79,417
Total Past Due	119,327	113,706
Current	6,049,215	5,899,793
Total loans	6,168,542	6,013,499
Accruing Loans [Member]
Summarized details of Loans
30-59 Days Past Due	45,299	31,478
60-89 Days Past Due	15,899	12,432
90 Days or More Past Due	2,497	4,925
Total Past Due	63,695	48,835
Current	13,862,945	13,625,464
Total loans	13,926,640	13,674,299
Accruing Loans [Member] | Commercial and industrial financing receivable [Member]
Summarized details of Loans
30-59 Days Past Due	11,615	3,513
60-89 Days Past Due	1,028	5,230
90 Days or More Past Due	1,051	3,755
Total Past Due	13,694	12,498
Current	3,654,681	3,656,163
Total loans	3,668,375	3,668,661
Accruing Loans [Member] | Commercial Real Estate Owner Occupied Portfolio Segment
Summarized details of Loans
30-59 Days Past Due	3,816	6,788
60-89 Days Past Due	3,716	304
90 Days or More Past Due	823	0
Total Past Due	8,355	7,092
Current	1,034,512	1,044,019
Total loans	1,042,867	1,051,111
Accruing Loans [Member] | Finance Leases Financing Receivable [Member]
Summarized details of Loans
30-59 Days Past Due	11	31
60-89 Days Past Due	29	73
90 Days or More Past Due	0	0
Total Past Due	40	104
Current	52,128	47,446
Total loans	52,168	47,550
Accruing Loans [Member] | Commercial and business lending
Summarized details of Loans
30-59 Days Past Due	15,442	10,332
60-89 Days Past Due	4,773	5,607
90 Days or More Past Due	1,874	3,755
Total Past Due	22,089	19,694
Current	4,741,321	4,747,628
Total loans	4,763,410	4,767,322
Accruing Loans [Member] | Commercial Real Estate Investor Portfolio Segment
Summarized details of Loans
30-59 Days Past Due	4,523	2,770
60-89 Days Past Due	3,790	2,200
90 Days or More Past Due	0	0
Total Past Due	8,313	4,970
Current	2,566,908	2,459,445
Total loans	2,575,221	2,464,415
Accruing Loans [Member] | Real estate construction
Summarized details of Loans
30-59 Days Past Due	1,736	873
60-89 Days Past Due	0	123
90 Days or More Past Due	0	481
Total Past Due	1,736	1,477
Current	527,746	540,763
Total loans	529,482	542,240
Accruing Loans [Member] | Commercial real estate lending
Summarized details of Loans
30-59 Days Past Due	6,259	3,643
60-89 Days Past Due	3,790	2,323
90 Days or More Past Due	0	481
Total Past Due	10,049	6,447
Current	3,094,654	3,000,208
Total loans	3,104,703	3,006,655
Accruing Loans [Member] | Total commercial [Member]
Summarized details of Loans
30-59 Days Past Due	21,701	13,975
60-89 Days Past Due	8,563	7,930
90 Days or More Past Due	1,874	4,236
Total Past Due	32,138	26,141
Current	7,835,975	7,747,836
Total loans	7,868,113	7,773,977
Accruing Loans [Member] | Home Equity [Member]
Summarized details of Loans
30-59 Days Past Due	11,412	9,399
60-89 Days Past Due	6,595	2,790
90 Days or More Past Due	0	0
Total Past Due	18,007	12,189
Current	2,439,135	2,445,608
Total loans	2,457,142	2,457,797
Accruing Loans [Member] | Installment
Summarized details of Loans
30-59 Days Past Due	2,322	1,784
60-89 Days Past Due	491	808
90 Days or More Past Due	623	689
Total Past Due	3,436	3,281
Current	531,565	551,786
Total loans	535,001	555,067
Accruing Loans [Member] | Total retail [Member]
Summarized details of Loans
30-59 Days Past Due	13,734	11,183
60-89 Days Past Due	7,086	3,598
90 Days or More Past Due	623	689
Total Past Due	21,443	15,470
Current	2,970,700	2,997,394
Total loans	2,992,143	3,012,864
Accruing Loans [Member] | Residential mortgage [Member]
Summarized details of Loans
30-59 Days Past Due	9,864	6,320
60-89 Days Past Due	250	904
90 Days or More Past Due	0	0
Total Past Due	10,114	7,224
Current	3,056,270	2,880,234
Total loans	3,066,384	2,887,458
Accruing Loans [Member] | Consumer Loan [Member]
Summarized details of Loans
30-59 Days Past Due	23,598	17,503
60-89 Days Past Due	7,336	4,502
90 Days or More Past Due	623	689
Total Past Due	31,557	22,694
Current	6,026,970	5,877,628
Total loans	6,058,527	5,900,322
Nonaccrual Loans [Member]
Summarized details of Loans
30-59 Days Past Due	15,673	15,134
60-89 Days Past Due	11,339	17,412
90 Days or More Past Due	162,331	170,256
Total Past Due	189,343	202,802
Current	137,742	153,970
Total loans	327,085	356,772
Nonaccrual Loans [Member] | Commercial and industrial financing receivable [Member]
Summarized details of Loans
30-59 Days Past Due	5,098	5,374
60-89 Days Past Due	2,024	6,933
90 Days or More Past Due	23,311	20,792
Total Past Due	30,433	33,099
Current	20,208	22,976
Total loans	50,641	56,075
Nonaccrual Loans [Member] | Commercial Real Estate Owner Occupied Portfolio Segment
Summarized details of Loans
30-59 Days Past Due	1,271	2,190
60-89 Days Past Due	477	185
90 Days or More Past Due	16,711	19,724
Total Past Due	18,459	22,099
Current	13,429	13,619
Total loans	31,888	35,718
Nonaccrual Loans [Member] | Finance Leases Financing Receivable [Member]
Summarized details of Loans
30-59 Days Past Due	0	0
60-89 Days Past Due	15	0
90 Days or More Past Due	843	858
Total Past Due	858	858
Current	8,182	9,786
Total loans	9,040	10,644
Nonaccrual Loans [Member] | Commercial and business lending
Summarized details of Loans
30-59 Days Past Due	6,369	7,564
60-89 Days Past Due	2,516	7,118
90 Days or More Past Due	40,865	41,374
Total Past Due	49,750	56,056
Current	41,819	46,381
Total loans	91,569	102,437
Nonaccrual Loans [Member] | Commercial Real Estate Investor Portfolio Segment
Summarized details of Loans
30-59 Days Past Due	2,362	2,332
60-89 Days Past Due	1,814	2,730
90 Days or More Past Due	29,748	31,529
Total Past Due	33,924	36,591
Current	55,106	62,761
Total loans	89,030	99,352
Nonaccrual Loans [Member] | Real estate construction
Summarized details of Loans
30-59 Days Past Due	0	36
60-89 Days Past Due	238	482
90 Days or More Past Due	17,661	18,625
Total Past Due	17,899	19,143
Current	18,572	22,663
Total loans	36,471	41,806
Nonaccrual Loans [Member] | Commercial real estate lending
Summarized details of Loans
30-59 Days Past Due	2,362	2,368
60-89 Days Past Due	2,052	3,212
90 Days or More Past Due	47,409	50,154
Total Past Due	51,823	55,734
Current	73,678	85,424
Total loans	125,501	141,158
Nonaccrual Loans [Member] | Total commercial [Member]
Summarized details of Loans
30-59 Days Past Due	8,731	9,932
60-89 Days Past Due	4,568	10,330
90 Days or More Past Due	88,274	91,528
Total Past Due	101,573	111,790
Current	115,497	131,805
Total loans	217,070	243,595
Nonaccrual Loans [Member] | Home Equity [Member]
Summarized details of Loans
30-59 Days Past Due	4,338	2,818
60-89 Days Past Due	2,268	2,408
90 Days or More Past Due	30,482	34,976
Total Past Due	37,088	40,202
Current	7,540	6,705
Total loans	44,628	46,907
Nonaccrual Loans [Member] | Installment
Summarized details of Loans
30-59 Days Past Due	367	403
60-89 Days Past Due	188	373
90 Days or More Past Due	848	599
Total Past Due	1,403	1,375
Current	1,224	1,340
Total loans	2,627	2,715
Nonaccrual Loans [Member] | Total retail [Member]
Summarized details of Loans
30-59 Days Past Due	4,705	3,221
60-89 Days Past Due	2,456	2,781
90 Days or More Past Due	31,330	35,575
Total Past Due	38,491	41,577
Current	8,764	8,045
Total loans	47,255	49,622
Nonaccrual Loans [Member] | Residential mortgage [Member]
Summarized details of Loans
30-59 Days Past Due	2,237	1,981
60-89 Days Past Due	4,315	4,301
90 Days or More Past Due	42,727	43,153
Total Past Due	49,279	49,435
Current	13,481	14,120
Total loans	62,760	63,555
Nonaccrual Loans [Member] | Consumer Loan [Member]
Summarized details of Loans
30-59 Days Past Due	6,942	5,202
60-89 Days Past Due	6,771	7,082
90 Days or More Past Due	74,057	78,728
Total Past Due	87,770	91,012
Current	22,245	22,165
Total loans	$ 110,015	$ 113,177