LOANS AND ALLOWANCE - Risk Categories of Loans by Class of Loans - (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Dec. 31, 2016
Risk category of loans
Loans	$ 3,047,250	$ 2,651,673
Pass
Risk category of loans
Loans	1,751,207	1,481,038
Special Mention
Risk category of loans
Loans	32,796	20,526
Substandard
Risk category of loans
Loans	22,250	18,626
Non-accrual
Risk category of loans
Loans	12,030	5,844
Substandard Commercial
Risk category of loans
Loans	748	1,421
Performing
Risk category of loans
Loans	166,239	169,710
Watch
Risk category of loans
Loans		90
Commercial
Risk category of loans
Loans	559,995	534,559
Commercial | Commercial and industrial
Risk category of loans
Loans	496,523	461,092
Commercial | Commercial and industrial | Pass
Risk category of loans
Loans	449,907	415,064
Commercial | Commercial and industrial | Special Mention
Risk category of loans
Loans	2,941	3,347
Commercial | Commercial and industrial | Substandard
Risk category of loans
Loans	2,914	5,297
Commercial | Commercial and industrial | Non-accrual
Risk category of loans
Loans	2,187	827
Commercial | Commercial and industrial | Substandard Commercial
Risk category of loans
Loans	38	55
Commercial | Commercial and industrial | Performing
Risk category of loans
Loans	38,536	36,502
Commercial | Agricultural
Risk category of loans
Loans	63,472	73,467
Commercial | Agricultural | Pass
Risk category of loans
Loans	52,043	61,637
Commercial | Agricultural | Special Mention
Risk category of loans
Loans	1,557	2,283
Commercial | Agricultural | Substandard
Risk category of loans
Loans	338
Commercial | Agricultural | Non-accrual
Risk category of loans
Loans	1,484	1,441
Commercial | Agricultural | Substandard Commercial
Risk category of loans
Loans	66	190
Commercial | Agricultural | Performing
Risk category of loans
Loans	7,984	7,916
Commercial real estate
Risk category of loans
Loans	1,425,275	1,162,696
Commercial real estate | Farm
Risk category of loans
Loans	103,783	111,807
Commercial real estate | Farm | Pass
Risk category of loans
Loans	79,619	89,297
Commercial real estate | Farm | Special Mention
Risk category of loans
Loans	2,950	2,209
Commercial real estate | Farm | Substandard
Risk category of loans
Loans	3,784	694
Commercial real estate | Farm | Non-accrual
Risk category of loans
Loans	1,504	1,340
Commercial real estate | Farm | Substandard Commercial
Risk category of loans
Loans	150	91
Commercial real estate | Farm | Performing
Risk category of loans
Loans	15,776	21,778
Commercial real estate | Hotel
Risk category of loans
Loans	120,829	91,213
Commercial real estate | Hotel | Pass
Risk category of loans
Loans	117,911	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	2,918	64
Commercial real estate | Construction and development
Risk category of loans
Loans	98,906	102,598
Commercial real estate | Construction and development | Pass
Risk category of loans
Loans	76,313	74,811
Commercial real estate | Construction and development | Special Mention
Risk category of loans
Loans		3,600
Commercial real estate | Construction and development | Substandard
Risk category of loans
Loans	2,579	2,287
Commercial real estate | Construction and development | Non-accrual
Risk category of loans
Loans		31
Commercial real estate | Construction and development | Substandard Commercial
Risk category of loans
Loans		7
Commercial real estate | Construction and development | Performing
Risk category of loans
Loans	20,014	18,260
Commercial real estate | Other
Risk category of loans
Loans	1,101,757	857,078
Commercial real estate | Other | Pass
Risk category of loans
Loans	975,414	752,063
Commercial real estate | Other | Special Mention
Risk category of loans
Loans	25,348	9,087
Commercial real estate | Other | Substandard
Risk category of loans
Loans	12,635	7,365
Commercial real estate | Other | Non-accrual
Risk category of loans
Loans	3,937	2,141
Commercial real estate | Other | Substandard Commercial
Risk category of loans
Loans	494	1,078
Commercial real estate | Other | Performing
Risk category of loans
Loans	83,929	85,254
Commercial real estate | Other | Watch
Risk category of loans
Loans		90
Residential
Risk category of loans
Loans	995,495	892,513
Residential | Substandard
Risk category of loans
Loans	3,171	4,176
Residential | Performing
Risk category of loans
Loans	990,233	886,198
Residential | Watch
Risk category of loans
Loans	2,091	2,139
Residential | 1-4 family
Risk category of loans
Loans	694,163	608,366
Residential | 1-4 family | Substandard
Risk category of loans
Loans	2,591	3,262
Residential | 1-4 family | Performing
Risk category of loans
Loans	689,607	603,102
Residential | 1-4 family | Watch
Risk category of loans
Loans	1,965	2,002
Residential | Home equity
Risk category of loans
Loans	301,332	284,147
Residential | Home equity | Substandard
Risk category of loans
Loans	580	914
Residential | Home equity | Performing
Risk category of loans
Loans	300,626	283,096
Residential | Home equity | Watch
Risk category of loans
Loans	126	137
Consumer
Risk category of loans
Loans	66,485	61,905
Consumer | Substandard
Risk category of loans
Loans	11	4
Consumer | Performing
Risk category of loans
Loans	65,560	61,839
Consumer | Loss
Risk category of loans
Loans	914	62
Consumer | Direct
Risk category of loans
Loans	66,281	61,574
Consumer | Direct | Substandard
Risk category of loans
Loans	11	4
Consumer | Direct | Performing
Risk category of loans
Loans	65,356	61,508
Consumer | Direct | Loss
Risk category of loans
Loans	914	62
Consumer | Indirect
Risk category of loans
Loans	204	331
Consumer | Indirect | Performing
Risk category of loans
Loans	204	$ 331
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
Minimum | Consumer loans not secured by 1-4 family residential real estate | Substandard
Risk category of loans
Period of loans past due	60 days
Maximum | Watch
Risk category of loans
Period of loans past due	89 days
Maximum | Consumer loans not secured by 1-4 family residential real estate | Substandard
Risk category of loans
Period of loans past due	119 days
Maximum | Commercial
Risk category of loans
Loans classified by delinquency	$ 250
Maximum | Commercial real estate
Risk category of loans
Loans classified by delinquency	$ 250