Loans, Allowance For Credit Losses (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance	$ 28,910	$ 26,450	$ 29,400	$ 26,530
Charge-offs	(547)	(606)	(814)	(1,159)
Recoveries	436	595	978	1,882
Provision	711	2,511	(54)	1,697
Ending balance	29,510	28,950	29,510	28,950
Ending balance, individually evaluated for impairment	1,518	3,242	1,518	3,242
Ending balance, collectively evaluated for impairment	27,992	25,708	27,992	25,708
Loan [Abstract]
Total Loans Receivable	2,502,872	2,370,699	2,502,872	2,370,699	$ 2,459,671
Ending balance, individually evaluated for impairment	27,458	30,206	27,458	30,206
Ending balance, collectively evaluated for impairment	2,475,414	2,340,493	2,475,414	2,340,493
Agricultural [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance	2,253	2,505	2,294	2,947
Charge-offs	(5)	(39)	(5)	(39)
Recoveries	17	29	29	67
Provision	(194)	(154)	(247)	(634)
Ending balance	2,071	2,341	2,071	2,341
Ending balance, individually evaluated for impairment	189	447	189	447
Ending balance, collectively evaluated for impairment	1,882	1,894	1,882	1,894
Loan [Abstract]
Total Loans Receivable	81,171	80,434	81,171	80,434	88,580
Ending balance, individually evaluated for impairment	3,718	5,052	3,718	5,052
Ending balance, collectively evaluated for impairment	77,453	75,382	77,453	75,382
Commercial and Financial [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance	4,658	3,899	4,837	4,531
Charge-offs	(176)	(237)	(206)	(457)
Recoveries	193	210	441	664
Provision	365	714	(32)	(152)
Ending balance	5,040	4,586	5,040	4,586
Ending balance, individually evaluated for impairment	706	908	706	908
Ending balance, collectively evaluated for impairment	4,334	3,678	4,334	3,678
Loan [Abstract]
Total Loans Receivable	219,693	203,150	219,693	203,150	218,632
Ending balance, individually evaluated for impairment	3,524	2,405	3,524	2,405
Ending balance, collectively evaluated for impairment	216,169	200,745	216,169	200,745
Real Estate: Construction and land development [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance	2,780	3,094	2,989	2,890
Charge-offs	0	(114)	0	(114)
Recoveries	2	29	145	410
Provision	272	156	(80)	(21)
Ending balance	3,054	3,165	3,054	3,165
Ending balance, individually evaluated for impairment	36	33	36	33
Ending balance, collectively evaluated for impairment	3,018	3,132	3,018	3,132
Loan [Abstract]
Total Loans Receivable	184,370	196,925	184,370	196,925
Ending balance, individually evaluated for impairment	942	690	942	690
Ending balance, collectively evaluated for impairment	183,428	196,235	183,428	196,235
Real Estate: Mortgage, farmland [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance	3,709	3,507	3,669	3,417
Charge-offs	0	0	0	0
Recoveries	19	0	19	0
Provision	(253)	502	(213)	592
Ending balance	3,475	4,009	3,475	4,009
Ending balance, individually evaluated for impairment	13	814	13	814
Ending balance, collectively evaluated for impairment	3,462	3,195	3,462	3,195
Loan [Abstract]
Total Loans Receivable	227,124	207,412	227,124	207,412	$ 215,286
Ending balance, individually evaluated for impairment	4,276	8,111	4,276	8,111
Ending balance, collectively evaluated for impairment	222,848	199,301	222,848	199,301
Real Estate: Mortgage, 1 to 4 family [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance	8,655	8,172	8,668	7,677
Charge-offs	(205)	(63)	(326)	(208)
Recoveries	147	234	245	367
Provision	305	(3)	315	504
Ending balance	8,902	8,340	8,902	8,340
Ending balance, individually evaluated for impairment	71	56	71	56
Ending balance, collectively evaluated for impairment	8,831	8,284	8,831	8,284
Loan [Abstract]
Total Loans Receivable	1,010,836	933,441	1,010,836	933,441
Ending balance, individually evaluated for impairment	6,980	5,540	6,980	5,540
Ending balance, collectively evaluated for impairment	1,003,856	927,901	1,003,856	927,901
Real Estate: Mortgage, multi-family and commercial [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance	5,794	4,358	5,700	4,045
Charge-offs	(53)	(43)	(54)	(43)
Recoveries	13	49	17	229
Provision	(57)	1,050	34	1,183
Ending balance	5,697	5,414	5,697	5,414
Ending balance, individually evaluated for impairment	443	889	443	889
Ending balance, collectively evaluated for impairment	5,254	4,525	5,254	4,525
Loan [Abstract]
Total Loans Receivable	699,106	668,234	699,106	668,234
Ending balance, individually evaluated for impairment	7,958	8,313	7,958	8,313
Ending balance, collectively evaluated for impairment	691,148	659,921	691,148	659,921
Others [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance	1,061	915	1,243	1,023
Charge-offs	(108)	(110)	(223)	(298)
Recoveries	45	44	82	145
Provision	273	246	169	225
Ending balance	1,271	1,095	1,271	1,095
Ending balance, individually evaluated for impairment	60	95	60	95
Ending balance, collectively evaluated for impairment	1,211	1,000	1,211	1,000
Loan [Abstract]
Total Loans Receivable	80,572	81,103	80,572	81,103
Ending balance, individually evaluated for impairment	60	95	60	95
Ending balance, collectively evaluated for impairment	$ 80,512	$ 81,008	$ 80,512	$ 81,008