LOANS - Credit Risk Profile of Loans (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017	Sep. 30, 2017
Financing Receivable, Recorded Investment [Line Items]
Purchased Credit Impaired	$ 7,037	$ 15,965
Total loans held for investment	3,363,354	3,190,485	$ 3,071,761
Grade 1 - 4 (Pass)
Financing Receivable, Recorded Investment [Line Items]
Loans, credit risk profile	2,941,273	2,767,798
Grade 5 (Watch)
Financing Receivable, Recorded Investment [Line Items]
Loans, credit risk profile	215,170	146,999
Grade 6 (Special Mention)
Financing Receivable, Recorded Investment [Line Items]
Loans, credit risk profile	70,647	130,126
Grade 7 (Substandard-Accrual)
Financing Receivable, Recorded Investment [Line Items]
Loans, credit risk profile	67,106	72,259
Grade 8 (Substandard-Nonaccrual)
Financing Receivable, Recorded Investment [Line Items]
Loans, credit risk profile	62,121	57,338
Grade 9 (Doubtful)
Financing Receivable, Recorded Investment [Line Items]
Loans, credit risk profile	0	0
Commercial & industrial
Financing Receivable, Recorded Investment [Line Items]
Total loans held for investment	1,142,733	1,066,266
Mortgage warehouse
Financing Receivable, Recorded Investment [Line Items]
Total loans held for investment	236,307	220,230
Owner occupied commercial real estate
Financing Receivable, Recorded Investment [Line Items]
Total loans held for investment	435,667	415,230
Commercial real estate
Financing Receivable, Recorded Investment [Line Items]
Total loans held for investment	1,133,427	1,067,779
Construction, land & land development
Financing Receivable, Recorded Investment [Line Items]
Total loans held for investment	153,257	164,952
Residential mortgage
Financing Receivable, Recorded Investment [Line Items]
Total loans held for investment	249,046	238,580
Consumer and other
Financing Receivable, Recorded Investment [Line Items]
Total loans held for investment	12,917	17,448
Originated
Financing Receivable, Recorded Investment [Line Items]
Purchased Credit Impaired	0	0
Total loans held for investment	3,074,574	2,676,491	2,485,239
Originated | Grade 1 - 4 (Pass)
Financing Receivable, Recorded Investment [Line Items]
Loans, credit risk profile	2,719,068	2,382,372
Originated | Grade 5 (Watch)
Financing Receivable, Recorded Investment [Line Items]
Loans, credit risk profile	177,269	78,394
Originated | Grade 6 (Special Mention)
Financing Receivable, Recorded Investment [Line Items]
Loans, credit risk profile	54,188	98,694
Originated | Grade 7 (Substandard-Accrual)
Financing Receivable, Recorded Investment [Line Items]
Loans, credit risk profile	66,194	65,171
Originated | Grade 8 (Substandard-Nonaccrual)
Financing Receivable, Recorded Investment [Line Items]
Loans, credit risk profile	57,855	51,860
Originated | Grade 9 (Doubtful)
Financing Receivable, Recorded Investment [Line Items]
Loans, credit risk profile	0	0
Originated | Commercial & industrial
Financing Receivable, Recorded Investment [Line Items]
Purchased Credit Impaired	0	0
Total loans held for investment	1,114,467	1,002,797
Originated | Commercial & industrial | Grade 1 - 4 (Pass)
Financing Receivable, Recorded Investment [Line Items]
Loans, credit risk profile	972,237	889,709
Originated | Commercial & industrial | Grade 5 (Watch)
Financing Receivable, Recorded Investment [Line Items]
Loans, credit risk profile	68,791	22,648
Originated | Commercial & industrial | Grade 6 (Special Mention)
Financing Receivable, Recorded Investment [Line Items]
Loans, credit risk profile	22,179	5,605
Originated | Commercial & industrial | Grade 7 (Substandard-Accrual)
Financing Receivable, Recorded Investment [Line Items]
Loans, credit risk profile	15,436	39,422
Originated | Commercial & industrial | Grade 8 (Substandard-Nonaccrual)
Financing Receivable, Recorded Investment [Line Items]
Loans, credit risk profile	35,824	45,413
Originated | Commercial & industrial | Grade 9 (Doubtful)
Financing Receivable, Recorded Investment [Line Items]
Loans, credit risk profile	0	0
Originated | Mortgage warehouse
Financing Receivable, Recorded Investment [Line Items]
Purchased Credit Impaired	0	0
Total loans held for investment	236,307	220,230
Originated | Mortgage warehouse | Grade 1 - 4 (Pass)
Financing Receivable, Recorded Investment [Line Items]
Loans, credit risk profile	236,307	220,230
Originated | Mortgage warehouse | Grade 5 (Watch)
Financing Receivable, Recorded Investment [Line Items]
Loans, credit risk profile	0	0
Originated | Mortgage warehouse | Grade 6 (Special Mention)
Financing Receivable, Recorded Investment [Line Items]
Loans, credit risk profile	0	0
Originated | Mortgage warehouse | Grade 7 (Substandard-Accrual)
Financing Receivable, Recorded Investment [Line Items]
Loans, credit risk profile	0	0
Originated | Mortgage warehouse | Grade 8 (Substandard-Nonaccrual)
Financing Receivable, Recorded Investment [Line Items]
Loans, credit risk profile	0	0
Originated | Mortgage warehouse | Grade 9 (Doubtful)
Financing Receivable, Recorded Investment [Line Items]
Loans, credit risk profile	0	0
Originated | Owner occupied commercial real estate
Financing Receivable, Recorded Investment [Line Items]
Purchased Credit Impaired	0	0
Total loans held for investment	382,886	327,906	312,162
Originated | Owner occupied commercial real estate | Grade 1 - 4 (Pass)
Financing Receivable, Recorded Investment [Line Items]
Loans, credit risk profile	353,041	314,497
Originated | Owner occupied commercial real estate | Grade 5 (Watch)
Financing Receivable, Recorded Investment [Line Items]
Loans, credit risk profile	9,546	3,096
Originated | Owner occupied commercial real estate | Grade 6 (Special Mention)
Financing Receivable, Recorded Investment [Line Items]
Loans, credit risk profile	9,918	7,658
Originated | Owner occupied commercial real estate | Grade 7 (Substandard-Accrual)
Financing Receivable, Recorded Investment [Line Items]
Loans, credit risk profile	6,887	2,655
Originated | Owner occupied commercial real estate | Grade 8 (Substandard-Nonaccrual)
Financing Receivable, Recorded Investment [Line Items]
Loans, credit risk profile	3,494	0
Originated | Owner occupied commercial real estate | Grade 9 (Doubtful)
Financing Receivable, Recorded Investment [Line Items]
Loans, credit risk profile	0	0
Originated | Commercial real estate
Financing Receivable, Recorded Investment [Line Items]
Purchased Credit Impaired	0	0
Total loans held for investment	1,013,927	823,361	806,327
Originated | Commercial real estate | Grade 1 - 4 (Pass)
Financing Receivable, Recorded Investment [Line Items]
Loans, credit risk profile	851,864	681,691
Originated | Commercial real estate | Grade 5 (Watch)
Financing Receivable, Recorded Investment [Line Items]
Loans, credit risk profile	90,208	45,149
Originated | Commercial real estate | Grade 6 (Special Mention)
Financing Receivable, Recorded Investment [Line Items]
Loans, credit risk profile	22,091	85,431
Originated | Commercial real estate | Grade 7 (Substandard-Accrual)
Financing Receivable, Recorded Investment [Line Items]
Loans, credit risk profile	36,385	11,090
Originated | Commercial real estate | Grade 8 (Substandard-Nonaccrual)
Financing Receivable, Recorded Investment [Line Items]
Loans, credit risk profile	13,379	0
Originated | Commercial real estate | Grade 9 (Doubtful)
Financing Receivable, Recorded Investment [Line Items]
Loans, credit risk profile	0	0
Originated | Construction, land & land development
Financing Receivable, Recorded Investment [Line Items]
Purchased Credit Impaired	0	0
Total loans held for investment	137,634	136,998	146,522
Originated | Construction, land & land development | Grade 1 - 4 (Pass)
Financing Receivable, Recorded Investment [Line Items]
Loans, credit risk profile	121,480	121,893
Originated | Construction, land & land development | Grade 5 (Watch)
Financing Receivable, Recorded Investment [Line Items]
Loans, credit risk profile	8,300	970
Originated | Construction, land & land development | Grade 6 (Special Mention)
Financing Receivable, Recorded Investment [Line Items]
Loans, credit risk profile	0	0
Originated | Construction, land & land development | Grade 7 (Substandard-Accrual)
Financing Receivable, Recorded Investment [Line Items]
Loans, credit risk profile	6,397	10,848
Originated | Construction, land & land development | Grade 8 (Substandard-Nonaccrual)
Financing Receivable, Recorded Investment [Line Items]
Loans, credit risk profile	1,457	3,287
Originated | Construction, land & land development | Grade 9 (Doubtful)
Financing Receivable, Recorded Investment [Line Items]
Loans, credit risk profile	0	0
Originated | Residential mortgage
Financing Receivable, Recorded Investment [Line Items]
Purchased Credit Impaired	0	0
Total loans held for investment	177,168	149,021	138,095
Originated | Residential mortgage | Grade 1 - 4 (Pass)
Financing Receivable, Recorded Investment [Line Items]
Loans, credit risk profile	171,997	138,239
Originated | Residential mortgage | Grade 5 (Watch)
Financing Receivable, Recorded Investment [Line Items]
Loans, credit risk profile	424	6,529
Originated | Residential mortgage | Grade 6 (Special Mention)
Financing Receivable, Recorded Investment [Line Items]
Loans, credit risk profile	0	0
Originated | Residential mortgage | Grade 7 (Substandard-Accrual)
Financing Receivable, Recorded Investment [Line Items]
Loans, credit risk profile	1,089	1,142
Originated | Residential mortgage | Grade 8 (Substandard-Nonaccrual)
Financing Receivable, Recorded Investment [Line Items]
Loans, credit risk profile	3,658	3,111
Originated | Residential mortgage | Grade 9 (Doubtful)
Financing Receivable, Recorded Investment [Line Items]
Loans, credit risk profile	0	0
Originated | Consumer and other
Financing Receivable, Recorded Investment [Line Items]
Purchased Credit Impaired	0	0
Total loans held for investment	12,185	16,178	15,418
Originated | Consumer and other | Grade 1 - 4 (Pass)
Financing Receivable, Recorded Investment [Line Items]
Loans, credit risk profile	12,142	16,113
Originated | Consumer and other | Grade 5 (Watch)
Financing Receivable, Recorded Investment [Line Items]
Loans, credit risk profile	0	2
Originated | Consumer and other | Grade 6 (Special Mention)
Financing Receivable, Recorded Investment [Line Items]
Loans, credit risk profile	0	0
Originated | Consumer and other | Grade 7 (Substandard-Accrual)
Financing Receivable, Recorded Investment [Line Items]
Loans, credit risk profile	0	14
Originated | Consumer and other | Grade 8 (Substandard-Nonaccrual)
Financing Receivable, Recorded Investment [Line Items]
Loans, credit risk profile	43	49
Originated | Consumer and other | Grade 9 (Doubtful)
Financing Receivable, Recorded Investment [Line Items]
Loans, credit risk profile	0	0
Acquired
Financing Receivable, Recorded Investment [Line Items]
Purchased Credit Impaired	7,037	15,965
Total loans held for investment	288,780	513,994	586,522
Acquired | Grade 1 - 4 (Pass)
Financing Receivable, Recorded Investment [Line Items]
Loans, credit risk profile	222,205	385,426
Acquired | Grade 5 (Watch)
Financing Receivable, Recorded Investment [Line Items]
Loans, credit risk profile	37,901	68,605
Acquired | Grade 6 (Special Mention)
Financing Receivable, Recorded Investment [Line Items]
Loans, credit risk profile	16,459	31,432
Acquired | Grade 7 (Substandard-Accrual)
Financing Receivable, Recorded Investment [Line Items]
Loans, credit risk profile	912	7,088
Acquired | Grade 8 (Substandard-Nonaccrual)
Financing Receivable, Recorded Investment [Line Items]
Loans, credit risk profile	4,266	5,478
Acquired | Grade 9 (Doubtful)
Financing Receivable, Recorded Investment [Line Items]
Loans, credit risk profile	0	0
Acquired | Commercial & industrial
Financing Receivable, Recorded Investment [Line Items]
Purchased Credit Impaired	1,563	3,237
Total loans held for investment	28,266	63,469	82,135
Acquired | Commercial & industrial | Grade 1 - 4 (Pass)
Financing Receivable, Recorded Investment [Line Items]
Loans, credit risk profile	16,044	38,000
Acquired | Commercial & industrial | Grade 5 (Watch)
Financing Receivable, Recorded Investment [Line Items]
Loans, credit risk profile	5,171	3,172
Acquired | Commercial & industrial | Grade 6 (Special Mention)
Financing Receivable, Recorded Investment [Line Items]
Loans, credit risk profile	3,638	11,101
Acquired | Commercial & industrial | Grade 7 (Substandard-Accrual)
Financing Receivable, Recorded Investment [Line Items]
Loans, credit risk profile	55	6,058
Acquired | Commercial & industrial | Grade 8 (Substandard-Nonaccrual)
Financing Receivable, Recorded Investment [Line Items]
Loans, credit risk profile	1,795	1,901
Acquired | Commercial & industrial | Grade 9 (Doubtful)
Financing Receivable, Recorded Investment [Line Items]
Loans, credit risk profile	0	0
Acquired | Mortgage warehouse
Financing Receivable, Recorded Investment [Line Items]
Total loans held for investment	0	0
Acquired | Owner occupied commercial real estate
Financing Receivable, Recorded Investment [Line Items]
Purchased Credit Impaired	14	4,062
Total loans held for investment	52,781	87,324	96,236
Acquired | Owner occupied commercial real estate | Grade 1 - 4 (Pass)
Financing Receivable, Recorded Investment [Line Items]
Loans, credit risk profile	44,106	72,592
Acquired | Owner occupied commercial real estate | Grade 5 (Watch)
Financing Receivable, Recorded Investment [Line Items]
Loans, credit risk profile	6,550	8,499
Acquired | Owner occupied commercial real estate | Grade 6 (Special Mention)
Financing Receivable, Recorded Investment [Line Items]
Loans, credit risk profile	162	0
Acquired | Owner occupied commercial real estate | Grade 7 (Substandard-Accrual)
Financing Receivable, Recorded Investment [Line Items]
Loans, credit risk profile	278	285
Acquired | Owner occupied commercial real estate | Grade 8 (Substandard-Nonaccrual)
Financing Receivable, Recorded Investment [Line Items]
Loans, credit risk profile	1,671	1,886
Acquired | Owner occupied commercial real estate | Grade 9 (Doubtful)
Financing Receivable, Recorded Investment [Line Items]
Loans, credit risk profile	0	0
Acquired | Commercial real estate
Financing Receivable, Recorded Investment [Line Items]
Purchased Credit Impaired	3,594	6,437
Total loans held for investment	119,500	244,418	262,415
Acquired | Commercial real estate | Grade 1 - 4 (Pass)
Financing Receivable, Recorded Investment [Line Items]
Loans, credit risk profile	90,396	173,765
Acquired | Commercial real estate | Grade 5 (Watch)
Financing Receivable, Recorded Investment [Line Items]
Loans, credit risk profile	14,186	43,775
Acquired | Commercial real estate | Grade 6 (Special Mention)
Financing Receivable, Recorded Investment [Line Items]
Loans, credit risk profile	11,324	20,129
Acquired | Commercial real estate | Grade 7 (Substandard-Accrual)
Financing Receivable, Recorded Investment [Line Items]
Loans, credit risk profile	0	0
Acquired | Commercial real estate | Grade 8 (Substandard-Nonaccrual)
Financing Receivable, Recorded Investment [Line Items]
Loans, credit risk profile	0	312
Acquired | Commercial real estate | Grade 9 (Doubtful)
Financing Receivable, Recorded Investment [Line Items]
Loans, credit risk profile	0	0
Acquired | Construction, land & land development
Financing Receivable, Recorded Investment [Line Items]
Purchased Credit Impaired	0	0
Total loans held for investment	15,623	27,954	47,334
Acquired | Construction, land & land development | Grade 1 - 4 (Pass)
Financing Receivable, Recorded Investment [Line Items]
Loans, credit risk profile	2,505	14,549
Acquired | Construction, land & land development | Grade 5 (Watch)
Financing Receivable, Recorded Investment [Line Items]
Loans, credit risk profile	11,893	12,136
Acquired | Construction, land & land development | Grade 6 (Special Mention)
Financing Receivable, Recorded Investment [Line Items]
Loans, credit risk profile	0	0
Acquired | Construction, land & land development | Grade 7 (Substandard-Accrual)
Financing Receivable, Recorded Investment [Line Items]
Loans, credit risk profile	530	555
Acquired | Construction, land & land development | Grade 8 (Substandard-Nonaccrual)
Financing Receivable, Recorded Investment [Line Items]
Loans, credit risk profile	695	714
Acquired | Construction, land & land development | Grade 9 (Doubtful)
Financing Receivable, Recorded Investment [Line Items]
Loans, credit risk profile	0	0
Acquired | Residential mortgage
Financing Receivable, Recorded Investment [Line Items]
Purchased Credit Impaired	1,866	2,229
Total loans held for investment	71,878	89,559	96,994
Acquired | Residential mortgage | Grade 1 - 4 (Pass)
Financing Receivable, Recorded Investment [Line Items]
Loans, credit risk profile	68,635	85,461
Acquired | Residential mortgage | Grade 5 (Watch)
Financing Receivable, Recorded Investment [Line Items]
Loans, credit risk profile	101	1,023
Acquired | Residential mortgage | Grade 6 (Special Mention)
Financing Receivable, Recorded Investment [Line Items]
Loans, credit risk profile	1,141	202
Acquired | Residential mortgage | Grade 7 (Substandard-Accrual)
Financing Receivable, Recorded Investment [Line Items]
Loans, credit risk profile	34	190
Acquired | Residential mortgage | Grade 8 (Substandard-Nonaccrual)
Financing Receivable, Recorded Investment [Line Items]
Loans, credit risk profile	101	454
Acquired | Residential mortgage | Grade 9 (Doubtful)
Financing Receivable, Recorded Investment [Line Items]
Loans, credit risk profile	0	0
Acquired | Consumer and other
Financing Receivable, Recorded Investment [Line Items]
Purchased Credit Impaired	0	0
Total loans held for investment	732	1,270	$ 1,408
Acquired | Consumer and other | Grade 1 - 4 (Pass)
Financing Receivable, Recorded Investment [Line Items]
Loans, credit risk profile	519	1,059
Acquired | Consumer and other | Grade 5 (Watch)
Financing Receivable, Recorded Investment [Line Items]
Loans, credit risk profile	0	0
Acquired | Consumer and other | Grade 6 (Special Mention)
Financing Receivable, Recorded Investment [Line Items]
Loans, credit risk profile	194	0
Acquired | Consumer and other | Grade 7 (Substandard-Accrual)
Financing Receivable, Recorded Investment [Line Items]
Loans, credit risk profile	15	0
Acquired | Consumer and other | Grade 8 (Substandard-Nonaccrual)
Financing Receivable, Recorded Investment [Line Items]
Loans, credit risk profile	4	211
Acquired | Consumer and other | Grade 9 (Doubtful)
Financing Receivable, Recorded Investment [Line Items]
Loans, credit risk profile	$ 0	$ 0