Fair Value Measurements (Narrative) (Details) - USD ($) $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2016	Dec. 31, 2015
Finite-Lived Intangible Assets [Line Items]
Impaired loans carrying amount	$ 20.4	$ 25.9
Impaired loans measured at fair value	14.9	21.6
Impaired loans life to date impairment	5.5	4.3
Mortgage Loan Servicing Rights [Member]
Finite-Lived Intangible Assets [Line Items]
Mortgage Servicing Rights (MSR) Impairment (Recovery)	$ 0.6	0.1
Covered And Noncovered [Member]
Finite-Lived Intangible Assets [Line Items]
Impairment charge of other real estate assets		$ 0.1