Securities (Details Textual) (Details) - USD ($)	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities	$ 442,929,000		$ 442,929,000		$ 447,498,000
Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net	0	$ 0	0	$ 0
Other than Temporary Impairment, Credit Losses Recognized in Earnings, Credit Losses on Debt Securities Held	0	$ 0	0	$ 0
Securities (Textual) [Abstract]
Callable Securities in Investment Portfolio	6,600,000		6,600,000
Pledged Financial Instruments, Not Separately Reported, Securities	545,400,000		545,400,000		547,200,000
Trading	1,598,000		1,598,000		1,324,000
Investments in obligations of individual states, counties or municipalities which exceed 10% of equity	0		0		0
Trading Securities, Equity	$ 20,133,000		$ 20,133,000		0
Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities					$ 20,584,000