LOANS AND ALLOWANCE - Risk Categories of Loans by Class of Loans - (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Dec. 31, 2016
Risk category of loans
Loans	$ 2,614,610	$ 2,651,673
Pass
Risk category of loans
Loans	1,473,548	1,481,038
Special Mention
Risk category of loans
Loans	15,532	20,526
Substandard
Risk category of loans
Loans	12,861	18,626
Substandard Commercial
Risk category of loans
Loans	1,563	1,421
Non-accrual
Risk category of loans
Loans	9,887	5,844
Performing
Risk category of loans
Loans	157,988	169,710
Watch
Risk category of loans
Loans		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	$ 528,166	534,559
Commercial | Maximum
Risk category of loans
Loans classified by delinquency	250
Commercial | Commercial and industrial
Risk category of loans
Loans	458,019	461,092
Commercial | Commercial and industrial | Pass
Risk category of loans
Loans	413,011	415,064
Commercial | Commercial and industrial | Special Mention
Risk category of loans
Loans	4,076	3,347
Commercial | Commercial and industrial | Substandard
Risk category of loans
Loans	4,033	5,297
Commercial | Commercial and industrial | Substandard Commercial
Risk category of loans
Loans	64	55
Commercial | Commercial and industrial | Non-accrual
Risk category of loans
Loans	367	827
Commercial | Commercial and industrial | Performing
Risk category of loans
Loans	36,468	36,502
Commercial | Agricultural
Risk category of loans
Loans	70,147	73,467
Commercial | Agricultural | Pass
Risk category of loans
Loans	61,333	61,637
Commercial | Agricultural | Special Mention
Risk category of loans
Loans	383	2,283
Commercial | Agricultural | Substandard
Risk category of loans
Loans		190
Commercial | Agricultural | Substandard Commercial
Risk category of loans
Loans	210
Commercial | Agricultural | Non-accrual
Risk category of loans
Loans	1,595	1,441
Commercial | Agricultural | Performing
Risk category of loans
Loans	6,626	7,916
Commercial Real Estate
Risk category of loans
Loans	1,143,213	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	108,037	111,807
Commercial Real Estate | Farm | Pass
Risk category of loans
Loans	86,076	89,297
Commercial Real Estate | Farm | Special Mention
Risk category of loans
Loans	2,147	2,209
Commercial Real Estate | Farm | Substandard
Risk category of loans
Loans	680	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	1,540	1,340
Commercial Real Estate | Farm | Performing
Risk category of loans
Loans	17,443	21,778
Commercial Real Estate | Hotel
Risk category of loans
Loans	101,685	91,213
Commercial Real Estate | Hotel | Pass
Risk category of loans
Loans	98,702	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	2,983	64
Commercial Real Estate | Construction and development
Risk category of loans
Loans	84,939	102,598
Commercial Real Estate | Construction and development | Pass
Risk category of loans
Loans	61,177	74,811
Commercial Real Estate | Construction and development | Special Mention
Risk category of loans
Loans	3,605	3,600
Commercial Real Estate | Construction and development | Substandard
Risk category of loans
Loans	652	2,287
Commercial Real Estate | Construction and development | Substandard Commercial
Risk category of loans
Loans	84	7
Commercial Real Estate | Construction and development | Non-accrual
Risk category of loans
Loans	1,441	31
Commercial Real Estate | Construction and development | Performing
Risk category of loans
Loans	17,980	18,260
Commercial Real Estate | Other
Risk category of loans
Loans	848,552	857,078
Commercial Real Estate | Other | Pass
Risk category of loans
Loans	753,249	752,063
Commercial Real Estate | Other | Special Mention
Risk category of loans
Loans	5,321	9,087
Commercial Real Estate | Other | Substandard
Risk category of loans
Loans	7,496	7,365
Commercial Real Estate | Other | Substandard Commercial
Risk category of loans
Loans	1,054	1,078
Commercial Real Estate | Other | Non-accrual
Risk category of loans
Loans	1,961	2,141
Commercial Real Estate | Other | Performing
Risk category of loans
Loans	79,471	85,254
Commercial Real Estate | Other | Watch
Risk category of loans
Loans		90
Residential
Risk category of loans
Loans	880,803	892,513
Residential | Substandard
Risk category of loans
Loans	3,539	4,176
Residential | Performing
Risk category of loans
Loans	876,584	886,198
Residential | Watch
Risk category of loans
Loans	680	2,139
Residential | 1-4 family
Risk category of loans
Loans	601,338	608,366
Residential | 1-4 family | Substandard
Risk category of loans
Loans	2,628	3,262
Residential | 1-4 family | Performing
Risk category of loans
Loans	598,074	603,102
Residential | 1-4 family | Watch
Risk category of loans
Loans	636	2,002
Residential | Home equity
Risk category of loans
Loans	279,465	284,147
Residential | Home equity | Substandard
Risk category of loans
Loans	911	914
Residential | Home equity | Performing
Risk category of loans
Loans	278,510	283,096
Residential | Home equity | Watch
Risk category of loans
Loans	44	137
Consumer
Risk category of loans
Loans	62,428	61,905
Consumer | Substandard
Risk category of loans
Loans	949	4
Consumer | Performing
Risk category of loans
Loans	61,450	61,839
Consumer | Loss
Risk category of loans
Loans	29	62
Consumer | Direct
Risk category of loans
Loans	62,132	61,574
Consumer | Direct | Substandard
Risk category of loans
Loans	949	4
Consumer | Direct | Performing
Risk category of loans
Loans	61,154	61,508
Consumer | Direct | Loss
Risk category of loans
Loans	29	62
Consumer | Indirect
Risk category of loans
Loans	296	331
Consumer | Indirect | Performing
Risk category of loans
Loans	$ 296	$ 331