Income Taxes (Narrative) (Details)	3 Months Ended	12 Months Ended
	Dec. 31, 2017 USD ($)	Dec. 31, 2017 USD ($) business	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Income Tax Disclosure [Abstract]
Reduction in income tax expense based upon initial revaluation of deferred tax assets and liabilities as result of tax reform	$ 2,284,000
Number of acquired banking companies | business		3
Amount of retained earnings which has no provision for federal income taxes	5,095,000	$ 5,095,000
Unrecorded deferred income tax liability	1,070,000	1,070,000
Unrecognized tax benefits	0	0	$ 0	$ 0
Increase in unrecognized tax benefits relative to tax positions taken		0
Accrual of unrecognized tax benefit, income tax penalties and interest accrued	$ 0	$ 0	$ 0	$ 0