ALLOWANCE FOR LOAN LOSSES (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2017
Allowance for loan losses:
Beginning balance	$ 31,220	$ 26,364
Provision	9,663	6,145
Charge-offs	(2,723)	(1,415)
Recoveries	73	842
Ending balance	38,233	31,936
Loans evaluated for impairment:
Collectively evaluated for impairment			$ 3,046,148	$ 3,104,089	$ 2,909,117
Individually evaluated for impairment			78,486	70,431	80,682
Purchased credit impaired			11,702	15,965	22,476
Total loans held for investment			3,136,336	3,190,485	3,012,275
Allowance for loans losses evaluated:
Collectively evaluated for impairment			23,685	25,478	23,827
Individually evaluated for impairment			14,450	5,667	8,092
Purchased credit impaired			98	75	17
Total allowance for loan losses	31,220	26,364	38,233	31,220	31,936
Commercial & industrial
Loans evaluated for impairment:
Total loans held for investment			1,038,715	1,066,266
Owner occupied commercial real estate
Loans evaluated for impairment:
Total loans held for investment			435,366	415,230
Commercial real estate
Loans evaluated for impairment:
Total loans held for investment			1,068,832	1,067,779
Construction, land & land development
Loans evaluated for impairment:
Total loans held for investment			148,732	164,952
Residential mortgage
Loans evaluated for impairment:
Total loans held for investment			242,529	238,580
Consumer and other
Loans evaluated for impairment:
Total loans held for investment			16,313	17,448
Originated
Allowance for loan losses:
Beginning balance	29,978	23,855
Provision	9,215	5,691
Charge-offs	(2,709)	(1,143)
Recoveries	51	708
Ending balance	36,535	29,111
Loans evaluated for impairment:
Collectively evaluated for impairment			2,620,188	2,620,375	2,237,049
Individually evaluated for impairment			64,539	56,116	45,162
Purchased credit impaired			0	0	0
Total loans held for investment			2,684,727	2,676,491	2,282,211
Allowance for loans losses evaluated:
Collectively evaluated for impairment			22,643	24,315	22,877
Individually evaluated for impairment			13,892	5,663	6,234
Purchased credit impaired			0	0	0
Total allowance for loan losses	29,978	23,855	36,535	29,978	29,111
Originated | Commercial & industrial
Allowance for loan losses:
Beginning balance	16,654
Ending balance	23,113
Loans evaluated for impairment:
Collectively evaluated for impairment			1,119,174	1,173,371
Individually evaluated for impairment			57,800	49,656
Purchased credit impaired			0	0
Total loans held for investment			1,176,974	1,223,027
Allowance for loans losses evaluated:
Collectively evaluated for impairment			9,653	11,245
Individually evaluated for impairment			13,460	5,409
Purchased credit impaired			0	0
Total allowance for loan losses	16,654		23,113	16,654
Originated | Commercial & industrial
Allowance for loan losses:
Beginning balance	16,654	9,491
Provision	9,156	6,234
Charge-offs	(2,699)	(1,135)
Recoveries	2	565
Ending balance	23,113	15,155
Loans evaluated for impairment:
Collectively evaluated for impairment					849,529
Individually evaluated for impairment					40,319
Purchased credit impaired					0
Total loans held for investment			991,125	1,002,797	889,848
Allowance for loans losses evaluated:
Collectively evaluated for impairment					9,041
Individually evaluated for impairment					6,114
Purchased credit impaired					0
Total allowance for loan losses	16,654	9,491	23,113	16,654	15,155
Originated | Owner occupied commercial real estate
Allowance for loan losses:
Beginning balance	2,748	2,609
Provision	123	154
Charge-offs	0	0
Recoveries	0	0
Ending balance	2,871	2,763
Loans evaluated for impairment:
Collectively evaluated for impairment			352,138	327,906	292,413
Individually evaluated for impairment			0	0	0
Purchased credit impaired			0	0	0
Total loans held for investment			352,138	327,906	292,413
Allowance for loans losses evaluated:
Collectively evaluated for impairment			2,871	2,748	2,763
Individually evaluated for impairment			0	0	0
Purchased credit impaired			0	0	0
Total allowance for loan losses	2,748	2,609	2,871	2,748	2,763
Originated | Commercial real estate
Allowance for loan losses:
Beginning balance	7,738	8,576
Provision	28	(229)
Charge-offs	0	0
Recoveries	0	0
Ending balance	7,766	8,347
Loans evaluated for impairment:
Collectively evaluated for impairment			861,502	823,361	807,005
Individually evaluated for impairment			185	0	2,021
Purchased credit impaired			0	0	0
Total loans held for investment			861,687	823,361	809,026
Allowance for loans losses evaluated:
Collectively evaluated for impairment			7,766	7,738	8,347
Individually evaluated for impairment			0	0	0
Purchased credit impaired			0	0	0
Total allowance for loan losses	7,738	8,576	7,766	7,738	8,347
Originated | Construction, land & land development
Allowance for loan losses:
Beginning balance	1,481	1,852
Provision	(20)	(316)
Charge-offs	0	0
Recoveries	0	0
Ending balance	1,461	1,536
Loans evaluated for impairment:
Collectively evaluated for impairment			118,859	133,711	151,114
Individually evaluated for impairment			3,415	3,287	0
Purchased credit impaired			0	0	0
Total loans held for investment			122,274	136,998	151,114
Allowance for loans losses evaluated:
Collectively evaluated for impairment			1,059	1,257	1,536
Individually evaluated for impairment			402	224	0
Purchased credit impaired			0	0	0
Total allowance for loan losses	1,481	1,852	1,461	1,481	1,536
Originated | Residential mortgage
Allowance for loan losses:
Beginning balance	1,136	1,134
Provision	21	(40)
Charge-offs	0	0
Recoveries	2	25
Ending balance	1,159	1,119
Loans evaluated for impairment:
Collectively evaluated for impairment			153,167	145,910	128,185
Individually evaluated for impairment			3,088	3,111	2,614
Purchased credit impaired			0	0	0
Total loans held for investment			156,255	149,021	130,799
Allowance for loans losses evaluated:
Collectively evaluated for impairment			1,159	1,136	1,119
Individually evaluated for impairment			0	0	0
Purchased credit impaired			0	0	0
Total allowance for loan losses	1,136	1,134	1,159	1,136	1,119
Originated | Consumer and other
Allowance for loan losses:
Beginning balance	221	193
Provision	(93)	(112)
Charge-offs	(10)	(8)
Recoveries	47	118
Ending balance	165	191
Loans evaluated for impairment:
Collectively evaluated for impairment			15,348	16,116	8,803
Individually evaluated for impairment			51	62	208
Purchased credit impaired			0	0	0
Total loans held for investment			15,399	16,178	9,011
Allowance for loans losses evaluated:
Collectively evaluated for impairment			135	191	71
Individually evaluated for impairment			30	30	120
Purchased credit impaired			0	0	0
Total allowance for loan losses	221	193	165	221	191
Acquired
Allowance for loan losses:
Beginning balance	1,242	2,509
Provision	448	454
Charge-offs	(14)	(272)
Recoveries	22	134
Ending balance	1,698	2,825
Loans evaluated for impairment:
Collectively evaluated for impairment			425,960	483,714	672,068
Individually evaluated for impairment			13,947	14,315	35,520
Purchased credit impaired			11,702	15,965	22,476
Total loans held for investment			451,609	513,994	730,064
Allowance for loans losses evaluated:
Collectively evaluated for impairment			1,042	1,163	950
Individually evaluated for impairment			558	4	1,858
Purchased credit impaired			98	75	17
Total allowance for loan losses	1,242	2,509	1,698	1,242	2,825
Acquired | Commercial & industrial
Allowance for loan losses:
Beginning balance	35	1,260
Provision	1	(517)
Charge-offs	0	(177)
Recoveries	6	20
Ending balance	42	586
Loans evaluated for impairment:
Collectively evaluated for impairment			34,313	49,494	97,312
Individually evaluated for impairment			11,116	10,738	22,017
Purchased credit impaired			2,161	3,237	3,805
Total loans held for investment			47,590	63,469	123,134
Allowance for loans losses evaluated:
Collectively evaluated for impairment			6	35	0
Individually evaluated for impairment			36	0	586
Purchased credit impaired			0	0	0
Total allowance for loan losses	35	1,260	42	35	586
Acquired | Owner occupied commercial real estate
Allowance for loan losses:
Beginning balance	0	0
Provision	513	1,060
Charge-offs	0	0
Recoveries	0	4
Ending balance	513	1,064
Loans evaluated for impairment:
Collectively evaluated for impairment			77,698	81,376	109,193
Individually evaluated for impairment			1,779	1,886	8,743
Purchased credit impaired			3,751	4,062	5,246
Total loans held for investment			83,228	87,324	123,182
Allowance for loans losses evaluated:
Collectively evaluated for impairment			0	0	0
Individually evaluated for impairment			513	0	1,064
Purchased credit impaired			0	0	0
Total allowance for loan losses	0	0	513	0	1,064
Acquired | Commercial real estate
Allowance for loan losses:
Beginning balance	658	437
Provision	(86)	(97)
Charge-offs	0	0
Recoveries	2	0
Ending balance	574	340
Loans evaluated for impairment:
Collectively evaluated for impairment			203,422	237,669	307,394
Individually evaluated for impairment			112	312	1,912
Purchased credit impaired			3,611	6,437	10,699
Total loans held for investment			207,145	244,418	320,005
Allowance for loans losses evaluated:
Collectively evaluated for impairment			574	658	340
Individually evaluated for impairment			0	0	0
Purchased credit impaired			0	0	0
Total allowance for loan losses	658	437	574	658	340
Acquired | Construction, land & land development
Allowance for loan losses:
Beginning balance	0	115
Provision	20	(85)
Charge-offs	0	(95)
Recoveries	0	74
Ending balance	20	9
Loans evaluated for impairment:
Collectively evaluated for impairment			25,749	27,240	49,478
Individually evaluated for impairment			709	714	1,336
Purchased credit impaired			0	0	18
Total loans held for investment			26,458	27,954	50,832
Allowance for loans losses evaluated:
Collectively evaluated for impairment			20	0	9
Individually evaluated for impairment			0	0	0
Purchased credit impaired			0	0	0
Total allowance for loan losses	0	115	20	0	9
Acquired | Residential mortgage
Allowance for loan losses:
Beginning balance	542	685
Provision	(16)	(106)
Charge-offs	0	0
Recoveries	13	32
Ending balance	539	611
Loans evaluated for impairment:
Collectively evaluated for impairment			84,079	86,876	107,036
Individually evaluated for impairment			16	454	1,296
Purchased credit impaired			2,179	2,229	2,708
Total loans held for investment			86,274	89,559	111,040
Allowance for loans losses evaluated:
Collectively evaluated for impairment			441	467	594
Individually evaluated for impairment			0	0	0
Purchased credit impaired			98	75	17
Total allowance for loan losses	542	685	539	542	611
Acquired | Consumer and other
Allowance for loan losses:
Beginning balance	7	12
Provision	16	199
Charge-offs	(14)	0
Recoveries	1	4
Ending balance	10	215
Loans evaluated for impairment:
Collectively evaluated for impairment			699	1,059	1,655
Individually evaluated for impairment			215	211	216
Purchased credit impaired			0	0	0
Total loans held for investment			914	1,270	1,871
Allowance for loans losses evaluated:
Collectively evaluated for impairment			1	3	7
Individually evaluated for impairment			9	4	208
Purchased credit impaired			0	0	0
Total allowance for loan losses	$ 7	$ 12	$ 10	$ 7	$ 215