Loans, Allowance for Loan Losses, and Credit Quality Consumer Loans by Credit Quality Indicator (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Consumer Loans By Credit Quality Indicator [Abstract]
Home equity	$ 1,762,002	$ 1,825,014
Installment	393,321	407,074
Residential mortgage	3,942,555	3,835,591
Total consumer	6,097,878	6,067,679
Performing Financing Receivable [Member]
Consumer Loans By Credit Quality Indicator [Abstract]
Home equity	1,719,075	1,777,421
Installment	390,912	404,514
Residential mortgage	3,868,263	3,758,688
Total consumer	5,978,250	5,940,623
Thirty To Eighty Nine Days Past Due [Member]
Consumer Loans By Credit Quality Indicator [Abstract]
Home equity	9,819	10,680
Installment	1,269	1,150
Residential mortgage	4,498	6,118
Total consumer	15,586	17,948
Potential Problem [Member]
Consumer Loans By Credit Quality Indicator [Abstract]
Home equity	1,051	2,113
Installment	0	50
Residential mortgage	2,091	3,312
Total consumer	3,142	5,475
Impaired [Member]
Consumer Loans By Credit Quality Indicator [Abstract]
Home equity	32,057	34,800
Installment	1,140	1,360
Residential mortgage	67,703	67,473
Total consumer	$ 100,900	$ 103,633