LOANS AND ALLOWANCE FOR LOAN LOSSES - Aging of the Recorded Investment in Past Due Loans - (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Recorded investment in nonaccrual and loans past due over 90 days still on accrual and aging of recorded investment in past due
Non-accrual	$ 16,195	$ 12,843
Past due over 90 days and still accruing	126
Aging of the recorded investment in past due loans
Total ending loan balance excluding accrued interest	2,548,803	2,155,392
Total Past Due	15,650	14,853
Loans Not Past Due	2,533,153	2,140,539
Accrued interest	7,315	5,878
30-59 Days Past Due
Aging of the recorded investment in past due loans
Total Past Due	3,231	5,164
60-89 Days Past Due
Aging of the recorded investment in past due loans
Total Past Due	5,107	2,597
Greater Than 90 Days Past Due
Aging of the recorded investment in past due loans
Total Past Due	7,312	7,092
Commercial
Aging of the recorded investment in past due loans
Total ending loan balance excluding accrued interest	474,165	445,664
Commercial | Commercial and industrial
Recorded investment in nonaccrual and loans past due over 90 days still on accrual and aging of recorded investment in past due
Non-accrual	625	654
Aging of the recorded investment in past due loans
Total ending loan balance excluding accrued interest	407,519	380,960
Total Past Due	487	342
Loans Not Past Due	407,032	380,618
Commercial | Commercial and industrial | 30-59 Days Past Due
Aging of the recorded investment in past due loans
Total Past Due	258	93
Commercial | Commercial and industrial | Greater Than 90 Days Past Due
Aging of the recorded investment in past due loans
Total Past Due	229	249
Commercial | Agricultural
Recorded investment in nonaccrual and loans past due over 90 days still on accrual and aging of recorded investment in past due
Non-accrual	1,558	7
Aging of the recorded investment in past due loans
Total ending loan balance excluding accrued interest	66,646	64,704
Total Past Due	1,560	27
Loans Not Past Due	65,086	64,677
Commercial | Agricultural | 30-59 Days Past Due
Aging of the recorded investment in past due loans
Total Past Due	2	20
Commercial | Agricultural | 60-89 Days Past Due
Aging of the recorded investment in past due loans
Total Past Due	1,450
Commercial | Agricultural | Greater Than 90 Days Past Due
Aging of the recorded investment in past due loans
Total Past Due	108	7
Commercial Real Estate
Aging of the recorded investment in past due loans
Total ending loan balance excluding accrued interest	1,093,659	925,884
Commercial Real Estate | Farm
Recorded investment in nonaccrual and loans past due over 90 days still on accrual and aging of recorded investment in past due
Non-accrual	1,363	308
Aging of the recorded investment in past due loans
Total ending loan balance excluding accrued interest	110,843	97,916
Total Past Due	959	119
Loans Not Past Due	109,884	97,797
Commercial Real Estate | Farm | 30-59 Days Past Due
Aging of the recorded investment in past due loans
Total Past Due	81
Commercial Real Estate | Farm | 60-89 Days Past Due
Aging of the recorded investment in past due loans
Total Past Due	694
Commercial Real Estate | Farm | Greater Than 90 Days Past Due
Aging of the recorded investment in past due loans
Total Past Due	184	119
Commercial Real Estate | Hotel
Aging of the recorded investment in past due loans
Total ending loan balance excluding accrued interest	87,720	72,193
Total Past Due	64	13
Loans Not Past Due	87,656	72,180
Commercial Real Estate | Hotel | 60-89 Days Past Due
Aging of the recorded investment in past due loans
Total Past Due	64	13
Commercial Real Estate | Construction and development
Recorded investment in nonaccrual and loans past due over 90 days still on accrual and aging of recorded investment in past due
Non-accrual	124	144
Aging of the recorded investment in past due loans
Total ending loan balance excluding accrued interest	82,550	77,394
Total Past Due	136	211
Loans Not Past Due	82,414	77,183
Commercial Real Estate | Construction and development | 30-59 Days Past Due
Aging of the recorded investment in past due loans
Total Past Due	27
Commercial Real Estate | Construction and development | 60-89 Days Past Due
Aging of the recorded investment in past due loans
Total Past Due		67
Commercial Real Estate | Construction and development | Greater Than 90 Days Past Due
Aging of the recorded investment in past due loans
Total Past Due	109	144
Commercial Real Estate | Other
Recorded investment in nonaccrual and loans past due over 90 days still on accrual and aging of recorded investment in past due
Non-accrual	3,968	4,791
Aging of the recorded investment in past due loans
Total ending loan balance excluding accrued interest	812,546	678,381
Total Past Due	3,028	3,576
Loans Not Past Due	809,518	674,805
Commercial Real Estate | Other | 30-59 Days Past Due
Aging of the recorded investment in past due loans
Total Past Due	226	873
Commercial Real Estate | Other | 60-89 Days Past Due
Aging of the recorded investment in past due loans
Total Past Due	691	102
Commercial Real Estate | Other | Greater Than 90 Days Past Due
Aging of the recorded investment in past due loans
Total Past Due	2,111	2,601
Residential
Aging of the recorded investment in past due loans
Total ending loan balance excluding accrued interest	919,640	727,073
Residential | 1-4 family
Recorded investment in nonaccrual and loans past due over 90 days still on accrual and aging of recorded investment in past due
Non-accrual	7,054	5,211
Aging of the recorded investment in past due loans
Total ending loan balance excluding accrued interest	632,522	438,808
Total Past Due	7,279	8,401
Loans Not Past Due	625,243	430,407
Residential | 1-4 family | 30-59 Days Past Due
Aging of the recorded investment in past due loans
Total Past Due	1,729	3,726
Residential | 1-4 family | 60-89 Days Past Due
Aging of the recorded investment in past due loans
Total Past Due	1,872	1,904
Residential | 1-4 family | Greater Than 90 Days Past Due
Aging of the recorded investment in past due loans
Total Past Due	3,678	2,771
Residential | Home equity
Recorded investment in nonaccrual and loans past due over 90 days still on accrual and aging of recorded investment in past due
Non-accrual	1,395	1,639
Aging of the recorded investment in past due loans
Total ending loan balance excluding accrued interest	287,118	288,265
Total Past Due	1,920	1,989
Loans Not Past Due	285,198	286,276
Residential | Home equity | 30-59 Days Past Due
Aging of the recorded investment in past due loans
Total Past Due	782	410
Residential | Home equity | 60-89 Days Past Due
Aging of the recorded investment in past due loans
Total Past Due	336	446
Residential | Home equity | Greater Than 90 Days Past Due
Aging of the recorded investment in past due loans
Total Past Due	802	1,133
Consumer
Aging of the recorded investment in past due loans
Total ending loan balance excluding accrued interest	61,339	56,771
Consumer | Direct
Recorded investment in nonaccrual and loans past due over 90 days still on accrual and aging of recorded investment in past due
Non-accrual	108	89
Aging of the recorded investment in past due loans
Total ending loan balance excluding accrued interest	60,948	56,312
Total Past Due	217	173
Loans Not Past Due	60,731	56,139
Consumer | Direct | 30-59 Days Past Due
Aging of the recorded investment in past due loans
Total Past Due	126	40
Consumer | Direct | 60-89 Days Past Due
Aging of the recorded investment in past due loans
Total Past Due		65
Consumer | Direct | Greater Than 90 Days Past Due
Aging of the recorded investment in past due loans
Total Past Due	91	68
Consumer | Indirect
Recorded investment in nonaccrual and loans past due over 90 days still on accrual and aging of recorded investment in past due
Past due over 90 days and still accruing	126
Aging of the recorded investment in past due loans
Total ending loan balance excluding accrued interest	391	459
Total Past Due		2
Loans Not Past Due	$ 391	457
Consumer | Indirect | 30-59 Days Past Due
Aging of the recorded investment in past due loans
Total Past Due		$ 2