Loans and Allowance for Loan Losses (Details 8) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Average recorded investment and interest income recognized on impaired loans
Average recorded investment	$ 13,060	$ 12,108	$ 13,019
Recognized interest income	158	114	637
Commercial [Member]
Average recorded investment and interest income recognized on impaired loans
Average recorded investment	7,875	9,834	9,222
Recognized interest income	88	97	465
Commercial [Member] | Owner occupied RE [Member]
Average recorded investment and interest income recognized on impaired loans
Average recorded investment	2,231	2,232	2,255
Recognized interest income	17	28	104
Commercial [Member] | Non-owner occupied RE [Member]
Average recorded investment and interest income recognized on impaired loans
Average recorded investment	3,758	3,927	4,144
Recognized interest income	50	29	199
Commercial [Member] | Business [Member]
Average recorded investment and interest income recognized on impaired loans
Average recorded investment	1,886	3,675	2,823
Recognized interest income	21	40	162
Commercial [Member] | Construction [Member]
Average recorded investment and interest income recognized on impaired loans
Average recorded investment
Recognized interest income
Consumer [Member]
Average recorded investment and interest income recognized on impaired loans
Average recorded investment	5,185	2,274	3,797
Recognized interest income	70	17	172
Consumer [Member] | Other [Member]
Average recorded investment and interest income recognized on impaired loans
Average recorded investment	168	182	174
Recognized interest income	1		6
Consumer [Member] | Real estate [Member]
Average recorded investment and interest income recognized on impaired loans
Average recorded investment	2,814	1,836	2,047
Recognized interest income	41	16	69
Consumer [Member] | Home equity [Member]
Average recorded investment and interest income recognized on impaired loans
Average recorded investment	2,203	256	1,576
Recognized interest income	28	1	97
Consumer [Member] | Construction [Member]
Average recorded investment and interest income recognized on impaired loans
Average recorded investment
Recognized interest income