Fair Value of Financial Instruments (Assets Measured at Fair Value Nonrecurring) (Details) - Nonrecurring Basis $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2015 USD ($)	Sep. 30, 2015 USD ($)
Nonrecurring Basis
Losses on impaired loans charged through allowance for loan losses	$ 4.1	$ 7.2
Significant Other Observable Inputs (Level 2)
Nonrecurring Basis
Impaired loans, aggregate outstanding principal balance	58.7	58.7
Impaired loans, fair value	$ 48.1	$ 48.1