Investment Securities (Narrative) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2016 USD ($) security item	Dec. 31, 2015 USD ($)
Securities [Line Items]
Available-for-sale Securities Pledged as Collateral | $	$ 116.7	$ 147.9
Percent of principal outstanding collected of held-to-maturity securities	85.00%
State and Municipal Tax-Exempt [Member]
Securities [Line Items]
Securities in unrealized loss positions qualitative disclosure number of positions | security	53
Number Of Impaired Municipal Securities, School Districts, Additional Private Insurance	20
Number Of Impaired Municipal Securities, Remaining	19
Number Of Impaired Municipal Securities School Districts State Qualified School Aid	34
Number Of Impaired Municipal Securities, School Districts, Insured	2
Number Of Impaired Municipal Securities, School Districts, Uninsured	2
Number Of Impaired Municipal Securities, Townships	9
Government Sponsored Entities (GSE) Mortgage-Backed Securities [Member]
Securities [Line Items]
Securities in unrealized loss positions qualitative disclosure number of positions | security	15
Number of securities, impaired for more than 12 months	0
Corporate Bonds [Member]
Securities [Line Items]
Securities in unrealized loss positions qualitative disclosure number of positions | security	12
Number of securities, impaired for more than 12 months	2
US Government Agency Obligations [Member]
Securities [Line Items]
Securities in unrealized loss positions qualitative disclosure number of positions | security	6
Number of securities, impaired for more than 12 months	0
Collateralized Mortgage Obligations GSE [Member]
Securities [Line Items]
Securities in unrealized loss positions qualitative disclosure number of positions | security	17
Number of securities, impaired for more than 12 months	9
Asset-Backed Security [Member]
Securities [Line Items]
Securities in unrealized loss positions qualitative disclosure number of positions | security	1
Unrealized loss of security from book value	0.02%
Maximum [Member] | State and Municipal Tax-Exempt [Member]
Securities [Line Items]
Unrealized loss of security from book value	8.60%
Maximum [Member] | Government Sponsored Entities (GSE) Mortgage-Backed Securities [Member]
Securities [Line Items]
Unrealized loss of security from book value	3.29%
Maximum [Member] | Corporate Bonds [Member]
Securities [Line Items]
Unrealized loss of security from book value	5.15%
Maximum [Member] | US Government Agency Obligations [Member]
Securities [Line Items]
Unrealized loss of security from book value	0.74%
Maximum [Member] | Collateralized Mortgage Obligations GSE [Member]
Securities [Line Items]
Unrealized loss of security from book value	4.47%