Investment Securities (Narrative) (Details) $ in Millions	9 Months Ended
	Sep. 30, 2018 USD ($) security	Sep. 30, 2017	Dec. 31, 2017 USD ($)
Securities [Line Items]
Available-for-sale securities pledged as collateral | $	$ 90.4		$ 105.9
Collection of the original recorded investment on HTM securities (percentage)		85.00%
Collateralized Mortgage Obligations GSE [Member]
Securities [Line Items]
Securities in unrealized loss positions qualitative disclosure number of positions	19
Number of securities, impaired for more than 12 months	19
Unrealized loss of security from book value	9.50%
Government Sponsored Entities (GSE) Mortgage-Backed Securities [Member]
Securities [Line Items]
Securities in unrealized loss positions qualitative disclosure number of positions	20
Number of securities, impaired for more than 12 months	18
Unrealized loss of security from book value	6.06%
US Government Agency Obligations [Member]
Securities [Line Items]
Securities in unrealized loss positions qualitative disclosure number of positions	9
Number of securities, impaired for more than 12 months	8
Unrealized loss of security from book value	6.68%
State and Municipal Tax-Exempt [Member]
Securities [Line Items]
Securities in unrealized loss positions qualitative disclosure number of positions	56
Number of securities, impaired for more than 12 months	29
Number of impaired municipal securities, insured school districts	23
Number of impaired municipal securities, unisured school districts	17
Number of impaired municipal securities, townships insured	9
Number of impaired municipal securities, townships uninsured	7
Unrealized loss of security from book value	12.29%
State and Municipal Taxable [Member]
Securities [Line Items]
Securities in unrealized loss positions qualitative disclosure number of positions	1
Unrealized loss of security from book value	2.78%
Corporate Bonds [Member]
Securities [Line Items]
Securities in unrealized loss positions qualitative disclosure number of positions	12
Number of securities, impaired for more than 12 months	4
Unrealized loss of security from book value	6.14%