Loans, Impaired Loans (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Recorded Investment
With no related allowance recorded	$ 18,261		$ 17,099
With an allowance recorded	1,224		3,550
Total	19,485		20,649
Unpaid Principal Balance
With no related allowance recorded	20,002		18,961
With an allowance recorded	1,255		3,574
Total	21,257		22,535
Related Allowance
With an allowance recorded	216		191
Average Recorded Investment
With no related allowance recorded	19,011	$ 20,157
With an allowance recorded	1,244	3,009
Total	20,255	23,166
Interest Income Recognized
With no related allowance recorded	263	319
With an allowance recorded	17	37
Total	280	356
Cash basis interest expense on impaired loans	20	0
Commercial and industrial [Member]
Recorded Investment
With no related allowance recorded	264		1,015
With an allowance recorded	288		296
Total	552		1,311
Unpaid Principal Balance
With no related allowance recorded	348		1,100
With an allowance recorded	288		301
Total	636		1,401
Related Allowance
With an allowance recorded	11		8
Average Recorded Investment
With no related allowance recorded	639	261
With an allowance recorded	291	322
Total	930	583
Interest Income Recognized
With no related allowance recorded	11	26
With an allowance recorded	4	4
Total	15	30
Commercial, secured by real estate [Member]
Recorded Investment
With no related allowance recorded	14,713		12,677
With an allowance recorded	155		2,660
Total	14,868		15,337
Unpaid Principal Balance
With no related allowance recorded	15,504		13,608
With an allowance recorded	155		2,660
Total	15,659		16,268
Related Allowance
With an allowance recorded	4		146
Average Recorded Investment
With no related allowance recorded	14,991	15,859
With an allowance recorded	157	1,931
Total	15,148	17,790
Interest Income Recognized
With no related allowance recorded	196	186
With an allowance recorded	3	24
Total	199	210
Residential real estate [Member]
Recorded Investment
With no related allowance recorded	2,688		2,822
With an allowance recorded	741		553
Total	3,429		3,375
Unpaid Principal Balance
With no related allowance recorded	3,413		3,516
With an allowance recorded	772		572
Total	4,185		4,088
Related Allowance
With an allowance recorded	189		29
Average Recorded Investment
With no related allowance recorded	2,791	3,219
With an allowance recorded	755	704
Total	3,546	3,923
Interest Income Recognized
With no related allowance recorded	45	89
With an allowance recorded	9	8
Total	54	97
Consumer [Member]
Recorded Investment
With no related allowance recorded	6		6
With an allowance recorded	40		41
Total	46		47
Unpaid Principal Balance
With no related allowance recorded	6		6
With an allowance recorded	40		41
Total	46		47
Related Allowance
With an allowance recorded	12		8
Average Recorded Investment
With no related allowance recorded	6	21
With an allowance recorded	41	52
Total	47	73
Interest Income Recognized
With no related allowance recorded	0	0
With an allowance recorded	1	1
Total	1	1
Agricultural [Member]
Recorded Investment
With no related allowance recorded	178		177
With an allowance recorded	0		0
Total	178		177
Unpaid Principal Balance
With no related allowance recorded	178		177
With an allowance recorded	0		0
Total	178		177
Related Allowance
With an allowance recorded	0		0
Average Recorded Investment
With no related allowance recorded	177	334
With an allowance recorded	0	0
Total	177	334
Interest Income Recognized
With no related allowance recorded	0	0
With an allowance recorded	0	0
Total	0	0
Other [Member]
Recorded Investment
With no related allowance recorded	412		402
With an allowance recorded	0		0
Total	412		402
Unpaid Principal Balance
With no related allowance recorded	553		554
With an allowance recorded	0		0
Total	553		554
Related Allowance
With an allowance recorded	0		$ 0
Average Recorded Investment
With no related allowance recorded	407	463
With an allowance recorded	0	0
Total	407	463
Interest Income Recognized
With no related allowance recorded	11	18
With an allowance recorded	0	0
Total	$ 11	$ 18