Loans, Allowance for Loan Losses, and Credit Quality Consumer Loans by Credit Quality Indicator (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Consumer Loans By Credit Quality Indicator [Abstract]
Home equity	$ 1,676,525	$ 1,825,014
Installment and Credit Cards	459,682	407,074
Residential mortgage	4,326,262	3,835,591
Total consumer	6,462,469	6,067,679
Performing Financing Receivable [Member]
Consumer Loans By Credit Quality Indicator [Abstract]
Home equity	1,633,033	1,777,421
Installment and Credit Cards	456,101	404,514
Residential mortgage	4,250,223	3,758,688
Total consumer	6,339,357	5,940,623
Thirty To Eighty Nine Days Past Due [Member]
Consumer Loans By Credit Quality Indicator [Abstract]
Home equity	10,738	10,680
Installment and Credit Cards	1,818	1,150
Residential mortgage	3,231	6,118
Total consumer	15,787	17,948
Potential Problem [Member]
Consumer Loans By Credit Quality Indicator [Abstract]
Home equity	911	2,113
Installment and Credit Cards	4	50
Residential mortgage	2,166	3,312
Total consumer	3,081	5,475
Impaired [Member]
Consumer Loans By Credit Quality Indicator [Abstract]
Home equity	31,843	34,800
Installment and Credit Cards	1,759	1,360
Residential mortgage	70,642	67,473
Total consumer	$ 104,244	$ 103,633