ALLOWANCE FOR LOAN LOSSES (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Dec. 31, 2017	Sep. 30, 2017
Allowance for loan losses:
Beginning balance	$ 35,086	$ 31,991	$ 31,220	$ 26,364
Provision	320	2,300	11,880	9,955
Charge-offs	(292)	(850)	(8,367)	(3,818)
Recoveries	72	39	453	979
Ending balance	35,186	33,480	35,186	33,480
Loans evaluated for impairment:
Collectively evaluated for impairment					$ 3,291,187	$ 3,104,089	$ 2,978,883
Individually evaluated for impairment					65,130	70,431	72,462
Purchased credit impaired					7,037	15,965	20,416
Total loans held for investment					3,363,354	3,190,485	3,071,761
Allowance for loans losses evaluated:
Collectively evaluated for impairment					25,906	25,478	25,572
Individually evaluated for impairment					9,170	5,667	7,774
Purchased credit impaired					110	75	134
Total allowance for loan losses	35,086	31,991	31,220	26,364	35,186	31,220	33,480
Commercial & industrial
Loans evaluated for impairment:
Total loans held for investment					1,142,733	1,066,266
Owner occupied commercial real estate
Loans evaluated for impairment:
Total loans held for investment					435,667	415,230
Commercial real estate
Loans evaluated for impairment:
Total loans held for investment					1,133,427	1,067,779
Construction, land & land development
Loans evaluated for impairment:
Total loans held for investment					153,257	164,952
Residential mortgage
Loans evaluated for impairment:
Total loans held for investment					249,046	238,580
Consumer and other
Loans evaluated for impairment:
Total loans held for investment					12,917	17,448
Originated
Allowance for loan losses:
Beginning balance	34,152	30,529	29,978	23,855
Provision	495	2,479	12,662	9,986
Charge-offs	(291)	(845)	(8,346)	(2,422)
Recoveries	29	18	91	762
Ending balance	34,385	32,181	34,385	32,181
Loans evaluated for impairment:
Collectively evaluated for impairment					3,016,712	2,620,375	2,438,715
Individually evaluated for impairment					57,862	56,116	46,524
Purchased credit impaired					0	0	0
Total loans held for investment					3,074,574	2,676,491	2,485,239
Allowance for loans losses evaluated:
Collectively evaluated for impairment					25,231	24,315	24,429
Individually evaluated for impairment					9,154	5,663	7,752
Purchased credit impaired					0	0	0
Total allowance for loan losses	34,152	30,529	29,978	23,855	34,385	29,978	32,181
Originated | Commercial & industrial
Allowance for loan losses:
Beginning balance			16,654
Ending balance	19,809	17,806	19,809	17,806
Loans evaluated for impairment:
Collectively evaluated for impairment					1,314,942	1,173,371	1,025,109
Individually evaluated for impairment					35,832	49,656	41,606
Purchased credit impaired					0	0	0
Total loans held for investment					1,350,774	1,223,027	1,066,715
Allowance for loans losses evaluated:
Collectively evaluated for impairment					11,215	11,245	10,391
Individually evaluated for impairment					8,594	5,409	7,415
Purchased credit impaired					0	0	0
Total allowance for loan losses	19,809	17,806	16,654	17,806	19,809	16,654	17,806
Originated | Commercial & industrial
Allowance for loan losses:
Beginning balance	20,527	16,606	16,654	9,491
Provision	(542)	2,031	11,327	10,002
Charge-offs	(178)	(836)	(8,177)	(2,280)
Recoveries	2	5	5	593
Ending balance	19,809	17,806	19,809	17,806
Loans evaluated for impairment:
Total loans held for investment					1,114,467	1,002,797
Allowance for loans losses evaluated:
Total allowance for loan losses	20,527	16,606	16,654	9,491	19,809	16,654	17,806
Originated | Owner occupied commercial real estate
Allowance for loan losses:
Beginning balance	3,351	2,825	2,748	2,609
Provision	9	85	612	301
Charge-offs	0	0	0	0
Recoveries	0	0	0	0
Ending balance	3,360	2,910	3,360	2,910
Loans evaluated for impairment:
Collectively evaluated for impairment					379,392	327,906	312,162
Individually evaluated for impairment					3,494	0	0
Purchased credit impaired					0	0	0
Total loans held for investment					382,886	327,906	312,162
Allowance for loans losses evaluated:
Collectively evaluated for impairment					2,829	2,748	2,910
Individually evaluated for impairment					531	0	0
Purchased credit impaired					0	0	0
Total allowance for loan losses	3,351	2,825	2,748	2,609	3,360	2,748	2,910
Originated | Commercial real estate
Allowance for loan losses:
Beginning balance	8,151	8,185	7,738	8,576
Provision	533	131	946	(260)
Charge-offs	0	0	0	0
Recoveries	0	0	0	0
Ending balance	8,684	8,316	8,684	8,316
Loans evaluated for impairment:
Collectively evaluated for impairment					1,000,548	823,361	806,125
Individually evaluated for impairment					13,379	0	202
Purchased credit impaired					0	0	0
Total loans held for investment					1,013,927	823,361	806,327
Allowance for loans losses evaluated:
Collectively evaluated for impairment					8,684	7,738	8,316
Individually evaluated for impairment					0	0	0
Purchased credit impaired					0	0	0
Total allowance for loan losses	8,151	8,185	7,738	8,576	8,684	7,738	8,316
Originated | Construction, land & land development
Allowance for loan losses:
Beginning balance	848	1,576	1,481	1,852
Provision	226	255	(407)	(21)
Charge-offs	0	0	0	0
Recoveries	0	0	0	0
Ending balance	1,074	1,831	1,074	1,831
Loans evaluated for impairment:
Collectively evaluated for impairment					136,177	133,711	143,385
Individually evaluated for impairment					1,457	3,287	3,137
Purchased credit impaired					0	0	0
Total loans held for investment					137,634	136,998	146,522
Allowance for loans losses evaluated:
Collectively evaluated for impairment					1,074	1,257	1,523
Individually evaluated for impairment					0	224	308
Purchased credit impaired					0	0	0
Total allowance for loan losses	848	1,576	1,481	1,852	1,074	1,481	1,831
Originated | Residential mortgage
Allowance for loan losses:
Beginning balance	1,110	1,165	1,136	1,134
Provision	120	(6)	89	(9)
Charge-offs	0	0	0	0
Recoveries	4	13	9	47
Ending balance	1,234	1,172	1,234	1,172
Loans evaluated for impairment:
Collectively evaluated for impairment					173,510	145,910	136,588
Individually evaluated for impairment					3,658	3,111	1,507
Purchased credit impaired					0	0	0
Total loans held for investment					177,168	149,021	138,095
Allowance for loans losses evaluated:
Collectively evaluated for impairment					1,234	1,136	1,172
Individually evaluated for impairment					0	0	0
Purchased credit impaired					0	0	0
Total allowance for loan losses	1,110	1,165	1,136	1,134	1,234	1,136	1,172
Originated | Consumer and other
Allowance for loan losses:
Beginning balance	165	172	221	193
Provision	149	(17)	95	(27)
Charge-offs	(113)	(9)	(169)	(142)
Recoveries	23	0	77	122
Ending balance	224	146	224	146
Loans evaluated for impairment:
Collectively evaluated for impairment					12,143	16,116	15,346
Individually evaluated for impairment					42	62	72
Purchased credit impaired					0	0	0
Total loans held for investment					12,185	16,178	15,418
Allowance for loans losses evaluated:
Collectively evaluated for impairment					195	191	117
Individually evaluated for impairment					29	30	29
Purchased credit impaired					0	0	0
Total allowance for loan losses	165	172	221	193	224	221	146
Acquired
Allowance for loan losses:
Beginning balance	934	1,462	1,242	2,509
Provision	(175)	(179)	(782)	(31)
Charge-offs	(1)	(5)	(21)	(1,396)
Recoveries	43	21	362	217
Ending balance	801	1,299	801	1,299
Loans evaluated for impairment:
Collectively evaluated for impairment					274,475	483,714	540,168
Individually evaluated for impairment					7,268	14,315	25,938
Purchased credit impaired					7,037	15,965	20,416
Total loans held for investment					288,780	513,994	586,522
Allowance for loans losses evaluated:
Collectively evaluated for impairment					675	1,163	1,143
Individually evaluated for impairment					16	4	22
Purchased credit impaired					110	75	134
Total allowance for loan losses	934	1,462	1,242	2,509	801	1,242	1,299
Acquired | Commercial & industrial
Allowance for loan losses:
Beginning balance	19	157	35	1,260
Provision	26	(145)	1	(984)
Charge-offs	(1)	(4)	(1)	(338)
Recoveries	2	7	11	77
Ending balance	46	15	46	15
Loans evaluated for impairment:
Collectively evaluated for impairment					22,101	49,494	61,035
Individually evaluated for impairment					4,602	10,738	17,761
Purchased credit impaired					1,563	3,237	3,339
Total loans held for investment					28,266	63,469	82,135
Allowance for loans losses evaluated:
Collectively evaluated for impairment					34	35	15
Individually evaluated for impairment					12	0	0
Purchased credit impaired					0	0	0
Total allowance for loan losses	19	157	35	1,260	46	35	15
Acquired | Owner occupied commercial real estate
Allowance for loan losses:
Beginning balance	153		0	0
Provision	(153)			957
Charge-offs	0			(961)
Recoveries	0			4
Ending balance	0	0	0	0
Loans evaluated for impairment:
Collectively evaluated for impairment					51,096	81,376	85,073
Individually evaluated for impairment					1,671	1,886	6,880
Purchased credit impaired					14	4,062	4,283
Total loans held for investment					52,781	87,324	96,236
Allowance for loans losses evaluated:
Collectively evaluated for impairment					0	0	0
Individually evaluated for impairment					0	0	0
Purchased credit impaired					0	0	0
Total allowance for loan losses	153	0	0	0	0	0	0
Acquired | Commercial real estate
Allowance for loan losses:
Beginning balance	290	487	658	437
Provision	15	167	(360)	214
Charge-offs	0	0	0	0
Recoveries	2	4	9	7
Ending balance	307	658	307	658
Loans evaluated for impairment:
Collectively evaluated for impairment					115,906	237,669	251,965
Individually evaluated for impairment					0	312	127
Purchased credit impaired					3,594	6,437	10,323
Total loans held for investment					119,500	244,418	262,415
Allowance for loans losses evaluated:
Collectively evaluated for impairment					307	658	569
Individually evaluated for impairment					0	0	0
Purchased credit impaired					0	0	89
Total allowance for loan losses	290	487	658	437	307	658	658
Acquired | Construction, land & land development
Allowance for loan losses:
Beginning balance	38	3	0	115
Provision	(8)	19	30	(72)
Charge-offs	0	0	0	(95)
Recoveries	0	1	0	75
Ending balance	30	23	30	23
Loans evaluated for impairment:
Collectively evaluated for impairment					14,928	27,240	46,396
Individually evaluated for impairment					695	714	921
Purchased credit impaired					0	0	17
Total loans held for investment					15,623	27,954	47,334
Allowance for loans losses evaluated:
Collectively evaluated for impairment					30	0	23
Individually evaluated for impairment					0	0	0
Purchased credit impaired					0	0	0
Total allowance for loan losses	38	3	0	115	30	0	23
Acquired | Residential mortgage
Allowance for loan losses:
Beginning balance	430	598	542	685
Provision	(54)	(10)	(466)	(136)
Charge-offs	0	0	0	0
Recoveries	38	8	338	47
Ending balance	414	596	414	596
Loans evaluated for impairment:
Collectively evaluated for impairment					69,911	86,876	94,503
Individually evaluated for impairment					101	454	37
Purchased credit impaired					1,866	2,229	2,454
Total loans held for investment					71,878	89,559	96,994
Allowance for loans losses evaluated:
Collectively evaluated for impairment					304	467	532
Individually evaluated for impairment					0	0	19
Purchased credit impaired					110	75	45
Total allowance for loan losses	430	598	542	685	414	542	596
Acquired | Consumer and other
Allowance for loan losses:
Beginning balance	4	217	7	12
Provision	(1)	(210)	13	(10)
Charge-offs	0	(1)	(20)	(2)
Recoveries	1	1	4	7
Ending balance	4	7	4	7
Loans evaluated for impairment:
Collectively evaluated for impairment					533	1,059	1,196
Individually evaluated for impairment					199	211	212
Purchased credit impaired					0	0	0
Total loans held for investment					732	1,270	1,408
Allowance for loans losses evaluated:
Collectively evaluated for impairment					0	3	4
Individually evaluated for impairment					4	4	3
Purchased credit impaired					0	0	0
Total allowance for loan losses	$ 4	$ 217	$ 7	$ 12	$ 4	$ 7	$ 7