Loans, Past Due (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Recorded investment of past due [Abstract]
Total past due	$ 15,195	$ 15,546
Current	1,073,917	1,064,478
PCI	1,805	1,859
Total financing receivables	1,090,917	1,081,883
90 Days or greater and accruing	64	68
Financing receivables on nonaccrual status [Abstract]
Total past due and non-accrual	10,661	12,170
Current and non-accrual	1,039	1,554
PCI Loans considered non accrual	0	0
Financing receivable nonaccrual status	11,700	13,724
Financing receivables on accrual status [Abstract]
Total past due and still accruing	4,534	3,376
Current and still accruing	1,072,878	1,062,924
PCI Loans still accruing	1,805	1,859
Total financing receivables and still accruing	$ 1,079,217	1,068,159
Minimum [Member]
Financing receivables on nonaccrual status [Abstract]
Period of past due after which loans considered as non accrual	90 days
30 to 59 Days Past Due [Member]
Recorded investment of past due [Abstract]
Total past due	$ 4,544	2,038
Financing receivables on nonaccrual status [Abstract]
Total past due and non-accrual	354	72
Financing receivables on accrual status [Abstract]
Total past due and still accruing	4,190	1,966
60 to 89 Days Past Due [Member]
Recorded investment of past due [Abstract]
Total past due	705	1,595
Financing receivables on nonaccrual status [Abstract]
Total past due and non-accrual	425	253
Financing receivables on accrual status [Abstract]
Total past due and still accruing	280	1,342
90 Days Or Greater [Member]
Recorded investment of past due [Abstract]
Total past due	9,946	11,913
Financing receivables on nonaccrual status [Abstract]
Total past due and non-accrual	9,882	11,845
Financing receivables on accrual status [Abstract]
Total past due and still accruing	64	68
Real Estate Loans [Member] | Mortgages [Member]
Recorded investment of past due [Abstract]
Total past due	1,392	1,958
Current	155,080	154,501
PCI	28	28
Total financing receivables	156,500	156,487
90 Days or greater and accruing	23	20
Financing receivables on nonaccrual status [Abstract]
Financing receivable nonaccrual status	1,009	1,079
Real Estate Loans [Member] | Mortgages [Member] | 30 to 59 Days Past Due [Member]
Recorded investment of past due [Abstract]
Total past due	592	483
Real Estate Loans [Member] | Mortgages [Member] | 60 to 89 Days Past Due [Member]
Recorded investment of past due [Abstract]
Total past due	83	789
Real Estate Loans [Member] | Mortgages [Member] | 90 Days Or Greater [Member]
Recorded investment of past due [Abstract]
Total past due	717	686
Real Estate Loans [Member] | Home Equity [Member]
Recorded investment of past due [Abstract]
Total past due	577	428
Current	57,558	58,390
PCI	0	0
Total financing receivables	58,135	58,818
90 Days or greater and accruing	17	0
Financing receivables on nonaccrual status [Abstract]
Financing receivable nonaccrual status	77	82
Real Estate Loans [Member] | Home Equity [Member] | 30 to 59 Days Past Due [Member]
Recorded investment of past due [Abstract]
Total past due	401	257
Real Estate Loans [Member] | Home Equity [Member] | 60 to 89 Days Past Due [Member]
Recorded investment of past due [Abstract]
Total past due	87	108
Real Estate Loans [Member] | Home Equity [Member] | 90 Days Or Greater [Member]
Recorded investment of past due [Abstract]
Total past due	89	63
Real Estate Loans [Member] | Commercial [Member]
Recorded investment of past due [Abstract]
Total past due	4,755	6,336
Current	328,325	311,608
PCI	1,291	1,321
Total financing receivables	334,371	319,265
90 Days or greater and accruing	4	36
Financing receivables on nonaccrual status [Abstract]
Financing receivable nonaccrual status	3,689	5,957
Real Estate Loans [Member] | Commercial [Member] | 30 to 59 Days Past Due [Member]
Recorded investment of past due [Abstract]
Total past due	1,888	999
Real Estate Loans [Member] | Commercial [Member] | 60 to 89 Days Past Due [Member]
Recorded investment of past due [Abstract]
Total past due	499	631
Real Estate Loans [Member] | Commercial [Member] | 90 Days Or Greater [Member]
Recorded investment of past due [Abstract]
Total past due	2,368	4,706
Real Estate Loans [Member] | Agricultural [Member]
Recorded investment of past due [Abstract]
Total past due	4,587	3,305
Current	290,960	281,215
PCI	0	0
Total financing receivables	295,547	284,520
90 Days or greater and accruing	0	0
Financing receivables on nonaccrual status [Abstract]
Financing receivable nonaccrual status	3,607	3,206
Real Estate Loans [Member] | Agricultural [Member] | 30 to 59 Days Past Due [Member]
Recorded investment of past due [Abstract]
Total past due	991	121
Real Estate Loans [Member] | Agricultural [Member] | 60 to 89 Days Past Due [Member]
Recorded investment of past due [Abstract]
Total past due	0	0
Real Estate Loans [Member] | Agricultural [Member] | 90 Days Or Greater [Member]
Recorded investment of past due [Abstract]
Total past due	3,596	3,184
Real Estate Loans [Member] | Construction [Member]
Recorded investment of past due [Abstract]
Total past due	0	0
Current	18,611	33,913
PCI	0	0
Total financing receivables	18,611	33,913
90 Days or greater and accruing	0	0
Financing receivables on nonaccrual status [Abstract]
Financing receivable nonaccrual status	0	0
Real Estate Loans [Member] | Construction [Member] | 30 to 59 Days Past Due [Member]
Recorded investment of past due [Abstract]
Total past due	0	0
Real Estate Loans [Member] | Construction [Member] | 60 to 89 Days Past Due [Member]
Recorded investment of past due [Abstract]
Total past due	0	0
Real Estate Loans [Member] | Construction [Member] | 90 Days Or Greater [Member]
Recorded investment of past due [Abstract]
Total past due	0	0
Consumer [Member]
Recorded investment of past due [Abstract]
Total past due	96	63
Current	9,677	9,795
PCI	0	0
Total financing receivables	9,773	9,858
90 Days or greater and accruing	0	12
Financing receivables on nonaccrual status [Abstract]
Financing receivable nonaccrual status	0	14
Consumer [Member] | 30 to 59 Days Past Due [Member]
Recorded investment of past due [Abstract]
Total past due	96	37
Consumer [Member] | 60 to 89 Days Past Due [Member]
Recorded investment of past due [Abstract]
Total past due	0	14
Consumer [Member] | 90 Days Or Greater [Member]
Recorded investment of past due [Abstract]
Total past due	0	12
Other Commercial Loans [Member]
Recorded investment of past due [Abstract]
Total past due	2,376	2,255
Current	71,461	71,353
PCI	486	510
Total financing receivables	74,323	74,118
90 Days or greater and accruing	20	0
Financing receivables on nonaccrual status [Abstract]
Financing receivable nonaccrual status	2,053	2,185
Other Commercial Loans [Member] | 30 to 59 Days Past Due [Member]
Recorded investment of past due [Abstract]
Total past due	396	141
Other Commercial Loans [Member] | 60 to 89 Days Past Due [Member]
Recorded investment of past due [Abstract]
Total past due	0	53
Other Commercial Loans [Member] | 90 Days Or Greater [Member]
Recorded investment of past due [Abstract]
Total past due	1,980	2,061
Other Agricultural Loans [Member]
Recorded investment of past due [Abstract]
Total past due	1,412	1,201
Current	41,833	40,985
PCI	0	0
Total financing receivables	43,245	42,186
90 Days or greater and accruing	0	0
Financing receivables on nonaccrual status [Abstract]
Financing receivable nonaccrual status	1,265	1,201
Other Agricultural Loans [Member] | 30 to 59 Days Past Due [Member]
Recorded investment of past due [Abstract]
Total past due	180	0
Other Agricultural Loans [Member] | 60 to 89 Days Past Due [Member]
Recorded investment of past due [Abstract]
Total past due	36	0
Other Agricultural Loans [Member] | 90 Days Or Greater [Member]
Recorded investment of past due [Abstract]
Total past due	1,196	1,201
State and Political Subdivision Loans [Member]
Recorded investment of past due [Abstract]
Total past due	0	0
Current	100,412	102,718
PCI	0	0
Total financing receivables	100,412	102,718
90 Days or greater and accruing	0	0
Financing receivables on nonaccrual status [Abstract]
Financing receivable nonaccrual status	0	0
State and Political Subdivision Loans [Member] | 30 to 59 Days Past Due [Member]
Recorded investment of past due [Abstract]
Total past due	0	0
State and Political Subdivision Loans [Member] | 60 to 89 Days Past Due [Member]
Recorded investment of past due [Abstract]
Total past due	0	0
State and Political Subdivision Loans [Member] | 90 Days Or Greater [Member]
Recorded investment of past due [Abstract]
Total past due	$ 0	$ 0