Loans, Allowance For Credit Losses (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance	$ 28,950	$ 27,290	$ 26,530	$ 26,510
Charge-offs	(305)	(478)	(1,464)	(1,518)
Recoveries	575	1,160	2,457	3,153
Provision	130	(1,832)	1,827	(2,004)
Ending balance	29,350	26,140	29,350	26,140
Ending balance, individually evaluated for impairment	3,000	2,113	3,000	2,113
Ending balance, collectively evaluated for impairment	26,350	24,027	26,350	24,027
Loan [Abstract]
Total Loans Receivable	2,419,894	2,226,932	2,419,894	2,226,932	$ 2,277,148
Ending balance, individually evaluated for impairment	33,785	35,935	33,785	35,935
Ending balance, collectively evaluated for impairment	2,386,109	2,190,997	2,386,109	2,190,997
Agricultural [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance	2,341	2,997	2,947	3,082
Charge-offs	(27)	(19)	(66)	(44)
Recoveries	56	0	123	173
Provision	92	201	(542)	(434)
Ending balance	2,462	2,777	2,462	2,777
Ending balance, individually evaluated for impairment	653	746	653	746
Ending balance, collectively evaluated for impairment	1,809	2,031	1,809	2,031
Loan [Abstract]
Total Loans Receivable	76,484	88,104	76,484	88,104	92,871
Ending balance, individually evaluated for impairment	6,181	12,276	6,181	12,276
Ending balance, collectively evaluated for impairment	70,303	75,828	70,303	75,828
Commercial and Financial [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance	4,586	4,011	4,531	4,517
Charge-offs	(21)	(38)	(478)	(172)
Recoveries	219	289	882	910
Provision	(43)	(252)	(194)	(1,245)
Ending balance	4,741	4,010	4,741	4,010
Ending balance, individually evaluated for impairment	913	221	913	221
Ending balance, collectively evaluated for impairment	3,828	3,789	3,828	3,789
Loan [Abstract]
Total Loans Receivable	214,199	188,365	214,199	188,365	192,995
Ending balance, individually evaluated for impairment	2,985	2,529	2,985	2,529
Ending balance, collectively evaluated for impairment	211,214	185,836	211,214	185,836
Real Estate: Construction and land development [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance	3,165	2,898	2,890	2,280
Charge-offs	0	0	(114)	0
Recoveries	33	186	443	792
Provision	(182)	(75)	(203)	(63)
Ending balance	3,016	3,009	3,016	3,009
Ending balance, individually evaluated for impairment	46	223	46	223
Ending balance, collectively evaluated for impairment	2,970	2,786	2,970	2,786
Loan [Abstract]
Total Loans Receivable	180,574	178,820	180,574	178,820
Ending balance, individually evaluated for impairment	1,161	2,877	1,161	2,877
Ending balance, collectively evaluated for impairment	179,413	175,943	179,413	175,943
Real Estate: Mortgage, farmland [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance	4,009	3,927	3,417	3,342
Charge-offs	(3)	(105)	(3)	(116)
Recoveries	0	0	0	0
Provision	2	(204)	594	392
Ending balance	4,008	3,618	4,008	3,618
Ending balance, individually evaluated for impairment	784	549	784	549
Ending balance, collectively evaluated for impairment	3,224	3,069	3,224	3,069
Loan [Abstract]
Total Loans Receivable	208,982	193,819	208,982	193,819	$ 202,340
Ending balance, individually evaluated for impairment	8,179	8,371	8,179	8,371
Ending balance, collectively evaluated for impairment	200,803	185,448	200,803	185,448
Real Estate: Mortgage, 1 to 4 family [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance	8,340	8,226	7,677	8,172
Charge-offs	(55)	(176)	(263)	(704)
Recoveries	203	276	570	767
Provision	98	(425)	602	(334)
Ending balance	8,586	7,901	8,586	7,901
Ending balance, individually evaluated for impairment	110	283	110	283
Ending balance, collectively evaluated for impairment	8,476	7,618	8,476	7,618
Loan [Abstract]
Total Loans Receivable	960,800	883,693	960,800	883,693
Ending balance, individually evaluated for impairment	7,097	6,497	7,097	6,497
Ending balance, collectively evaluated for impairment	953,703	877,196	953,703	877,196
Real Estate: Mortgage, multi-family and commercial [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance	5,414	4,201	4,045	4,223
Charge-offs	(86)	0	(130)	(66)
Recoveries	7	358	236	379
Provision	107	(589)	1,291	(566)
Ending balance	5,442	3,970	5,442	3,970
Ending balance, individually evaluated for impairment	409	62	409	62
Ending balance, collectively evaluated for impairment	5,033	3,908	5,033	3,908
Loan [Abstract]
Total Loans Receivable	694,771	619,214	694,771	619,214
Ending balance, individually evaluated for impairment	8,097	3,356	8,097	3,356
Ending balance, collectively evaluated for impairment	686,674	615,858	686,674	615,858
Others [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance	1,095	1,030	1,023	894
Charge-offs	(113)	(140)	(410)	(416)
Recoveries	57	51	203	132
Provision	56	(86)	279	246
Ending balance	1,095	855	1,095	855
Ending balance, individually evaluated for impairment	85	29	85	29
Ending balance, collectively evaluated for impairment	1,010	826	1,010	826
Loan [Abstract]
Total Loans Receivable	84,084	74,917	84,084	74,917
Ending balance, individually evaluated for impairment	85	29	85	29
Ending balance, collectively evaluated for impairment	$ 83,999	$ 74,888	$ 83,999	$ 74,888