Contingencies and Guarantees (Narratives) (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011	Sep. 30, 2011
Loss Contingencies [Line Items]
Allowance for unfunded lending commitments	$ 5.8	$ 6.4	$ 6.4
Short-term guarantees	69.6
Allowance for loan loss associated with loans sold with recourse	2.3	1.7	2.0
Residential Mortgage [Member]
Loss Contingencies [Line Items]
Financing Receivable, Loans Sold to Third Party Investors	28.5	28.1	29.4
Financing Receivable, Reserve For Loans Sold to Third Party Investors	1.1	0.5	0.4
Manufactured housing [Member]
Loss Contingencies [Line Items]
Financing Receivable, Loans Sold to Third Party Investors	10.7		11.4
Financing Receivable, Reserve For Loans Sold to Third Party Investors	$ 1.2	$ 1.3	$ 1.6