Derivative Financial Instruments (Narrative) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Derivative [Line Items]
Notional amount	$ 41.0	$ 192.5
Fixed Interest Swaps [Member]
Derivative [Line Items]
Notional amount	41.0	92.5
Fixed Interest Swaps On Commercial Loans [Member]
Derivative [Line Items]
Notional amount		100.0
Interest Rate Lock Commitments [Member]
Derivative [Line Items]
Notional amount	23.4	8.7
Forward Commitments [Member]
Derivative [Line Items]
Notional amount	32.0	10.2
Customer Derivative Instruments [Member]
Derivative [Line Items]
Notional amount	456.1	448.5
Offsetting Counter Party Derivative Instruments [Member]
Derivative [Line Items]
Notional amount	$ 456.1	$ 448.5