Loans, Credit Quality Indicators (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019	Sep. 30, 2019
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	$ 2,767,125	$ 2,639,104	$ 2,637,938
Excellent [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	80,387	68,021
Good [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	358,778	311,157
Satisfactory [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	1,735,585	1,728,780
Monitor [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	459,092	420,993
Special Mention [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	80,694	66,810
Substandard [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	52,589	43,343
Agricultural [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	96,321	91,317	91,621
Agricultural [Member] | Excellent [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	3,174	3,594
Agricultural [Member] | Good [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	11,212	12,380
Agricultural [Member] | Satisfactory [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	44,687	43,308
Agricultural [Member] | Monitor [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	28,217	24,857
Agricultural [Member] | Special Mention [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	6,624	3,110
Agricultural [Member] | Substandard [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	2,407	4,068
Commercial and Financial [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	335,463	221,323	219,362
Commercial and Financial [Member] | Excellent [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	15,023	3,461
Commercial and Financial [Member] | Good [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	62,843	47,843
Commercial and Financial [Member] | Satisfactory [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	181,807	117,114
Commercial and Financial [Member] | Monitor [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	61,300	44,543
Commercial and Financial [Member] | Special Mention [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	9,147	5,157
Commercial and Financial [Member] | Substandard [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	5,343	3,205
Real Estate: Construction, 1 to 4 family residential [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	70,527	80,209
Real Estate: Construction, 1 to 4 family residential [Member] | Excellent [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	1	260
Real Estate: Construction, 1 to 4 family residential [Member] | Good [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	13,969	8,868
Real Estate: Construction, 1 to 4 family residential [Member] | Satisfactory [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	38,486	51,093
Real Estate: Construction, 1 to 4 family residential [Member] | Monitor [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	16,441	17,505
Real Estate: Construction, 1 to 4 family residential [Member] | Special Mention [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	1,315	2,483
Real Estate: Construction, 1 to 4 family residential [Member] | Substandard [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	315	0
Real Estate: Construction, land development and commercial [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	114,270	108,410
Real Estate: Construction, land development and commercial [Member] | Excellent [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	231	190
Real Estate: Construction, land development and commercial [Member] | Good [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	16,492	23,217
Real Estate: Construction, land development and commercial [Member] | Satisfactory [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	61,231	47,987
Real Estate: Construction, land development and commercial [Member] | Monitor [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	28,008	29,009
Real Estate: Construction, land development and commercial [Member] | Special Mention [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	7,595	7,428
Real Estate: Construction, land development and commercial [Member] | Substandard [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	713	579
Real Estate: Mortgage, farmland [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	243,689	242,730	$ 237,513
Real Estate: Mortgage, farmland [Member] | Excellent [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	5,968	3,630
Real Estate: Mortgage, farmland [Member] | Good [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	42,037	40,118
Real Estate: Mortgage, farmland [Member] | Satisfactory [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	130,185	134,738
Real Estate: Mortgage, farmland [Member] | Monitor [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	55,917	53,147
Real Estate: Mortgage, farmland [Member] | Special Mention [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	6,100	3,033
Real Estate: Mortgage, farmland [Member] | Substandard [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	3,482	8,064
Real Estate: Mortgage, 1 to 4 family first liens [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	900,224	910,742
Real Estate: Mortgage, 1 to 4 family first liens [Member] | Excellent [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	2,395	3,209
Real Estate: Mortgage, 1 to 4 family first liens [Member] | Good [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	43,348	32,474
Real Estate: Mortgage, 1 to 4 family first liens [Member] | Satisfactory [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	710,236	751,215
Real Estate: Mortgage, 1 to 4 family first liens [Member] | Monitor [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	114,949	96,353
Real Estate: Mortgage, 1 to 4 family first liens [Member] | Special Mention [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	13,424	11,167
Real Estate: Mortgage, 1 to 4 family first liens [Member] | Substandard [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	15,872	16,324
Real Estate: Mortgage, 1 to 4 family junior liens [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	131,477	149,227
Real Estate: Mortgage, 1 to 4 family junior liens [Member] | Excellent [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	268	261
Real Estate: Mortgage, 1 to 4 family junior liens [Member] | Good [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	3,284	4,233
Real Estate: Mortgage, 1 to 4 family junior liens [Member] | Satisfactory [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	118,885	136,079
Real Estate: Mortgage, 1 to 4 family junior liens [Member] | Monitor [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	5,575	5,473
Real Estate: Mortgage, 1 to 4 family junior liens [Member] | Special Mention [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	1,635	1,469
Real Estate: Mortgage, 1 to 4 family junior liens [Member] | Substandard [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	1,830	1,712
Real Estate: Mortgage, multi-family [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	371,167	350,761
Real Estate: Mortgage, multi-family [Member] | Excellent [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	17,824	18,955
Real Estate: Mortgage, multi-family [Member] | Good [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	56,624	47,871
Real Estate: Mortgage, multi-family [Member] | Satisfactory [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	203,078	189,391
Real Estate: Mortgage, multi-family [Member] | Monitor [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	59,787	60,965
Real Estate: Mortgage, multi-family [Member] | Special Mention [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	15,439	27,559
Real Estate: Mortgage, multi-family [Member] | Substandard [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	18,415	6,020
Real Estate: Mortgage, commercial [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	417,042	402,181
Real Estate: Mortgage, commercial [Member] | Excellent [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	28,533	27,017
Real Estate: Mortgage, commercial [Member] | Good [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	94,886	79,467
Real Estate: Mortgage, commercial [Member] | Satisfactory [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	191,744	206,196
Real Estate: Mortgage, commercial [Member] | Monitor [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	78,640	81,381
Real Estate: Mortgage, commercial [Member] | Special Mention [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	19,103	4,802
Real Estate: Mortgage, commercial [Member] | Substandard [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	4,136	3,318
Loans to individuals [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	30,521	32,308
Loans to individuals [Member] | Excellent [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	0	0
Loans to individuals [Member] | Good [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	160	221
Loans to individuals [Member] | Satisfactory [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	29,685	31,385
Loans to individuals [Member] | Monitor [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	436	437
Loans to individuals [Member] | Special Mention [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	164	212
Loans to individuals [Member] | Substandard [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	76	53
Obligations of state and political subdivisions [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	56,424	49,896
Obligations of state and political subdivisions [Member] | Excellent [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	6,970	7,444
Obligations of state and political subdivisions [Member] | Good [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	13,923	14,465
Obligations of state and political subdivisions [Member] | Satisfactory [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	25,561	20,274
Obligations of state and political subdivisions [Member] | Monitor [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	9,822	7,323
Obligations of state and political subdivisions [Member] | Special Mention [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	148	390
Obligations of state and political subdivisions [Member] | Substandard [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	$ 0	$ 0