Extinguishment of Debt (Details Textual)	1 Months Ended	12 Months Ended
	Jan. 31, 2016 USD ($) Advance $ / shares	Dec. 31, 2017	Dec. 31, 2016 USD ($)	Dec. 31, 2015
Extinguishment Of Debt [Line Items]
Average interest rate during the year		1.03%	0.54%	0.27%
Losses from the extinguishment of debt			$ (242,000)
Federal Home Loan Bank Advances
Extinguishment Of Debt [Line Items]
Number of federal home loan bank advances paid off | Advance	2
Extinguishment of debt, amount	$ 4,500,000
Average interest rate during the year	4.01%	0.33%	0.31%	0.10%
Losses from the extinguishment of debt	$ 242,000
Prepayment penalties after tax	$ 160,000
Extinguishment of debt effect on earnings per share | $ / shares	$ (0.04)
Debt instrument alternative wholesale borrowing rate	1.44%
Estimated annual interest expense savings	$ 130,000