LOANS AND ALLOWANCE - Risk Categories of Loans by Class of Loans - (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2017	Dec. 31, 2016
Risk category of loans
Loans	$ 3,028,686	$ 2,651,673
Pass
Risk category of loans
Loans	1,706,542	1,481,038
Special Mention
Risk category of loans
Loans	56,196	20,526
Substandard
Risk category of loans
Loans	18,851	18,626
Substandard Commercial
Risk category of loans
Loans	921	1,421
Non-accrual
Risk category of loans
Loans	10,706	5,844
Performing
Risk category of loans
Loans	186,285	169,710
Watch
Risk category of loans
Loans	43	90
Minimum
Risk category of loans
Credit relationships with an outstanding balance	$ 1,000
Minimum | Substandard
Risk category of loans
Period of loans past due	90 days
Minimum | Watch
Risk category of loans
Period of loans past due	60 days
Minimum | Loss
Risk category of loans
Period of loans past due	119 days
Maximum | Watch
Risk category of loans
Period of loans past due	89 days
Consumer loans not secured by 1-4 family residential real estate | Minimum | Substandard
Risk category of loans
Period of loans past due	60 days
Consumer loans not secured by 1-4 family residential real estate | Maximum | Substandard
Risk category of loans
Period of loans past due	119 days
Commercial
Risk category of loans
Loans	$ 555,629	534,559
Commercial | Maximum
Risk category of loans
Loans classified by delinquency	250
Commercial | Commercial and industrial
Risk category of loans
Loans	492,942	461,092
Commercial | Commercial and industrial | Pass
Risk category of loans
Loans	444,240	415,064
Commercial | Commercial and industrial | Special Mention
Risk category of loans
Loans	3,805	3,347
Commercial | Commercial and industrial | Substandard
Risk category of loans
Loans	4,112	5,297
Commercial | Commercial and industrial | Substandard Commercial
Risk category of loans
Loans	50	55
Commercial | Commercial and industrial | Non-accrual
Risk category of loans
Loans	440	827
Commercial | Commercial and industrial | Performing
Risk category of loans
Loans	40,295	36,502
Commercial | Agricultural
Risk category of loans
Loans	62,687	73,467
Commercial | Agricultural | Pass
Risk category of loans
Loans	52,895	61,637
Commercial | Agricultural | Special Mention
Risk category of loans
Loans	532	2,283
Commercial | Agricultural | Substandard
Risk category of loans
Loans	287	190
Commercial | Agricultural | Substandard Commercial
Risk category of loans
Loans	81
Commercial | Agricultural | Non-accrual
Risk category of loans
Loans	1,488	1,441
Commercial | Agricultural | Performing
Risk category of loans
Loans	7,389	7,916
Commercial | Agricultural | Watch
Risk category of loans
Loans	15
Commercial Real Estate
Risk category of loans
Loans	1,423,915	1,162,696
Commercial Real Estate | Maximum
Risk category of loans
Loans classified by delinquency	250
Commercial Real Estate | Farm
Risk category of loans
Loans	101,859	111,807
Commercial Real Estate | Farm | Pass
Risk category of loans
Loans	78,852	89,297
Commercial Real Estate | Farm | Special Mention
Risk category of loans
Loans	2,550	2,209
Commercial Real Estate | Farm | Substandard
Risk category of loans
Loans	2,376	694
Commercial Real Estate | Farm | Substandard Commercial
Risk category of loans
Loans	151	91
Commercial Real Estate | Farm | Non-accrual
Risk category of loans
Loans	1,508	1,340
Commercial Real Estate | Farm | Performing
Risk category of loans
Loans	16,422	21,778
Commercial Real Estate | Hotel
Risk category of loans
Loans	117,027	91,213
Commercial Real Estate | Hotel | Pass
Risk category of loans
Loans	114,077	88,166
Commercial Real Estate | Hotel | Substandard
Risk category of loans
Loans		2,983
Commercial Real Estate | Hotel | Non-accrual
Risk category of loans
Loans	2,950	64
Commercial Real Estate | Construction and development
Risk category of loans
Loans	123,521	102,598
Commercial Real Estate | Construction and development | Pass
Risk category of loans
Loans	93,126	74,811
Commercial Real Estate | Construction and development | Special Mention
Risk category of loans
Loans	4,467	3,600
Commercial Real Estate | Construction and development | Substandard
Risk category of loans
Loans	56	2,287
Commercial Real Estate | Construction and development | Substandard Commercial
Risk category of loans
Loans		7
Commercial Real Estate | Construction and development | Non-accrual
Risk category of loans
Loans	1,416	31
Commercial Real Estate | Construction and development | Performing
Risk category of loans
Loans	24,456	18,260
Commercial Real Estate | Other
Risk category of loans
Loans	1,081,508	857,078
Commercial Real Estate | Other | Pass
Risk category of loans
Loans	923,352	752,063
Commercial Real Estate | Other | Special Mention
Risk category of loans
Loans	44,842	9,087
Commercial Real Estate | Other | Substandard
Risk category of loans
Loans	12,020	7,365
Commercial Real Estate | Other | Substandard Commercial
Risk category of loans
Loans	639	1,078
Commercial Real Estate | Other | Non-accrual
Risk category of loans
Loans	2,904	2,141
Commercial Real Estate | Other | Performing
Risk category of loans
Loans	97,723	85,254
Commercial Real Estate | Other | Watch
Risk category of loans
Loans	28	90
Residential
Risk category of loans
Loans	983,915	892,513
Residential | Substandard
Risk category of loans
Loans	3,416	4,176
Residential | Performing
Risk category of loans
Loans	978,183	886,198
Residential | Watch
Risk category of loans
Loans	2,316	2,139
Residential | 1-4 family
Risk category of loans
Loans	684,187	608,366
Residential | 1-4 family | Substandard
Risk category of loans
Loans	2,897	3,262
Residential | 1-4 family | Performing
Risk category of loans
Loans	679,188	603,102
Residential | 1-4 family | Watch
Risk category of loans
Loans	2,102	2,002
Residential | Home equity
Risk category of loans
Loans	299,728	284,147
Residential | Home equity | Substandard
Risk category of loans
Loans	519	914
Residential | Home equity | Performing
Risk category of loans
Loans	298,995	283,096
Residential | Home equity | Watch
Risk category of loans
Loans	214	137
Consumer
Risk category of loans
Loans	65,227	61,905
Consumer | Substandard
Risk category of loans
Loans	28	4
Consumer | Performing
Risk category of loans
Loans	64,255	61,839
Consumer | Loss
Risk category of loans
Loans	944	62
Consumer | Direct
Risk category of loans
Loans	64,958	61,574
Consumer | Direct | Substandard
Risk category of loans
Loans	28	4
Consumer | Direct | Performing
Risk category of loans
Loans	63,986	61,508
Consumer | Direct | Loss
Risk category of loans
Loans	944	62
Consumer | Indirect
Risk category of loans
Loans	269	331
Consumer | Indirect | Performing
Risk category of loans
Loans	$ 269	$ 331