LOANS AND ALLOWANCE FOR LOAN LOSSES (Summary of Aging of the Loan Portfolio by Segment) (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Financing Receivable, Recorded Investment, Past Due [Line Items]
Greater than 90 Days and still Accruing	$ 9,532	$ 3,532
Total Loans	9,411,598	7,141,552
Nonaccrual	28,110	21,743
Current	9,242,170	7,053,016
Purchased Impaired
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	94,746	39,021
Current	75,851	35,418
30 to 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	25,731	16,873
60 to 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	11,309	7,367
Construction and Land Development
Financing Receivable, Recorded Investment, Past Due [Line Items]
Greater than 90 Days and still Accruing	442	1,340
Total Loans	1,178,054	948,791
Nonaccrual	9,221	5,610
Current	1,160,172	936,857
Construction and Land Development | Purchased Impaired
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	5,042	2,838
Current	3,640	2,773
Construction and Land Development | 30 to 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	1,351	1,248
Construction and Land Development | 60 to 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	1,826	898
Commercial Real Estate - Owner Occupied
Financing Receivable, Recorded Investment, Past Due [Line Items]
Greater than 90 Days and still Accruing	3,586	0
Total Loans	1,283,125	943,933
Nonaccrual	3,202	2,708
Current	1,245,684	925,910
Commercial Real Estate - Owner Occupied | Purchased Impaired
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	25,896	14,790
Current	21,974	13,931
Commercial Real Estate - Owner Occupied | 30 to 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	4,218	444
Commercial Real Estate - Owner Occupied | 60 to 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	539	81
Commercial Real Estate - Non-Owner Occupied
Financing Receivable, Recorded Investment, Past Due [Line Items]
Greater than 90 Days and still Accruing	0	194
Total Loans	2,427,251	1,713,659
Nonaccrual	1,812	2,992
Current	2,403,372	1,703,592
Commercial Real Estate - Non-Owner Occupied | Purchased Impaired
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	21,575	6,610
Current	19,731	6,189
Commercial Real Estate - Non-Owner Occupied | 30 to 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	492	187
Commercial Real Estate - Non-Owner Occupied | 60 to 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	0	84
Multifamily Real Estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Greater than 90 Days and still Accruing	0	0
Total Loans	542,662	357,079
Nonaccrual	0	0
Current	542,023	356,999
Multifamily Real Estate | Purchased Impaired
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	86	80
Current	86	80
Multifamily Real Estate | 30 to 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	553	0
Multifamily Real Estate | 60 to 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	0	0
Commercial & Industrial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Greater than 90 Days and still Accruing	256	214
Total Loans	1,154,583	612,023
Nonaccrual	1,404	316
Current	1,147,957	609,829
Commercial & Industrial | Purchased Impaired
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	2,299	408
Current	1,165	408
Commercial & Industrial | 30 to 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	2,239	1,147
Commercial & Industrial | 60 to 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	428	109
Residential 1-4 Family - Commercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Greater than 90 Days and still Accruing	378	579
Total Loans	719,798	612,395
Nonaccrual	1,956	1,085
Current	696,964	598,935
Residential 1-4 Family - Commercial | Purchased Impaired
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	16,073	9,414
Current	10,385	8,630
Residential 1-4 Family - Commercial | 30 to 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	2,535	1,682
Residential 1-4 Family - Commercial | 60 to 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	1,892	700
Residential 1-4 Family - Mortgage
Financing Receivable, Recorded Investment, Past Due [Line Items]
Greater than 90 Days and still Accruing	2,543	546
Total Loans	611,728	485,690
Nonaccrual	8,535	6,269
Current	575,590	468,763
Residential 1-4 Family - Mortgage | Purchased Impaired
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	16,761	3,733
Current	12,693	2,764
Residential 1-4 Family - Mortgage | 30 to 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	4,506	3,838
Residential 1-4 Family - Mortgage | 60 to 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	3,793	2,541
Auto
Financing Receivable, Recorded Investment, Past Due [Line Items]
Greater than 90 Days and still Accruing	211	40
Total Loans	306,196	282,474
Nonaccrual	525	413
Current	302,738	278,295
Auto | Purchased Impaired
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	9	0
Current	9
Auto | 30 to 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	2,414	3,541
Auto | 60 to 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	299	185
HELOC
Financing Receivable, Recorded Investment, Past Due [Line Items]
Greater than 90 Days and still Accruing	1,291	217
Total Loans	612,116	537,521
Nonaccrual	1,273	2,075
Current	597,198	531,180
HELOC | Purchased Impaired
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	6,179	950
Current	5,395	445
HELOC | 30 to 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	4,783	2,382
HELOC | 60 to 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	1,392	717
Consumer and all other
Financing Receivable, Recorded Investment, Past Due [Line Items]
Greater than 90 Days and still Accruing	825	402
Total Loans	576,085	647,987
Nonaccrual	182	275
Current	570,472	642,656
Consumer and all other | Purchased Impaired
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	826	198
Current	773	198
Consumer and all other | 30 to 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	2,640	2,404
Consumer and all other | 60 to 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	$ 1,140	$ 2,052