LOANS AND ALLOWANCE FOR LOAN LOSSES (Loans Receivables Related Risk Rating Excluding Purchased Impaired Loans) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Financing Receivable, Recorded Investment [Line Items]
Total Loans	$ 9,716,207	$ 7,141,552
Construction and Land Development
Financing Receivable, Recorded Investment [Line Items]
Total Loans	1,194,821	948,791
Commercial Real Estate - Owner Occupied
Financing Receivable, Recorded Investment [Line Items]
Total Loans	1,337,345	943,933
Commercial Real Estate - Non-Owner Occupied
Financing Receivable, Recorded Investment [Line Items]
Total Loans	2,467,410	1,713,659
Multifamily Real Estate
Financing Receivable, Recorded Investment [Line Items]
Total Loans	548,231	357,079
Commercial and Industrial
Financing Receivable, Recorded Investment [Line Items]
Total Loans	1,317,135	612,023
Residential 1-4 Family - Commercial
Financing Receivable, Recorded Investment [Line Items]
Total Loans	713,750	612,395
Residential 1-4 Family - Mortgage
Financing Receivable, Recorded Investment [Line Items]
Total Loans	600,578	485,690
Auto
Financing Receivable, Recorded Investment [Line Items]
Total Loans	301,943	282,474
HELOC
Financing Receivable, Recorded Investment [Line Items]
Total Loans	613,383	537,521
Consumer and all other
Financing Receivable, Recorded Investment [Line Items]
Total Loans	621,611	647,987
Excluding Purchased Impaired
Financing Receivable, Recorded Investment [Line Items]
Total Loans	9,625,986	7,102,531
Excluding Purchased Impaired | Pass
Financing Receivable, Recorded Investment [Line Items]
Total Loans	9,344,002	6,880,526
Excluding Purchased Impaired | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Total Loans	201,174	184,654
Excluding Purchased Impaired | Substandard
Financing Receivable, Recorded Investment [Line Items]
Total Loans	80,810	34,114
Excluding Purchased Impaired | Doubtful
Financing Receivable, Recorded Investment [Line Items]
Total Loans	0	3,237
Excluding Purchased Impaired | Construction and Land Development
Financing Receivable, Recorded Investment [Line Items]
Total Loans	1,186,167	945,953
Excluding Purchased Impaired | Construction and Land Development | Pass
Financing Receivable, Recorded Investment [Line Items]
Total Loans	1,130,577	869,111
Excluding Purchased Impaired | Construction and Land Development | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Total Loans	43,894	62,517
Excluding Purchased Impaired | Construction and Land Development | Substandard
Financing Receivable, Recorded Investment [Line Items]
Total Loans	11,696	14,325
Excluding Purchased Impaired | Construction and Land Development | Doubtful
Financing Receivable, Recorded Investment [Line Items]
Total Loans	0	0
Excluding Purchased Impaired | Commercial Real Estate - Owner Occupied
Financing Receivable, Recorded Investment [Line Items]
Total Loans	1,311,701	929,143
Excluding Purchased Impaired | Commercial Real Estate - Owner Occupied | Pass
Financing Receivable, Recorded Investment [Line Items]
Total Loans	1,231,422	872,130
Excluding Purchased Impaired | Commercial Real Estate - Owner Occupied | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Total Loans	50,939	52,268
Excluding Purchased Impaired | Commercial Real Estate - Owner Occupied | Substandard
Financing Receivable, Recorded Investment [Line Items]
Total Loans	29,340	4,745
Excluding Purchased Impaired | Commercial Real Estate - Owner Occupied | Doubtful
Financing Receivable, Recorded Investment [Line Items]
Total Loans	0	0
Excluding Purchased Impaired | Commercial Real Estate - Non-Owner Occupied
Financing Receivable, Recorded Investment [Line Items]
Total Loans	2,450,075	1,707,049
Excluding Purchased Impaired | Commercial Real Estate - Non-Owner Occupied | Pass
Financing Receivable, Recorded Investment [Line Items]
Total Loans	2,425,500	1,681,314
Excluding Purchased Impaired | Commercial Real Estate - Non-Owner Occupied | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Total Loans	17,648	19,899
Excluding Purchased Impaired | Commercial Real Estate - Non-Owner Occupied | Substandard
Financing Receivable, Recorded Investment [Line Items]
Total Loans	6,927	5,836
Excluding Purchased Impaired | Commercial Real Estate - Non-Owner Occupied | Doubtful
Financing Receivable, Recorded Investment [Line Items]
Total Loans	0	0
Excluding Purchased Impaired | Multifamily Real Estate
Financing Receivable, Recorded Investment [Line Items]
Total Loans	548,143	356,999
Excluding Purchased Impaired | Multifamily Real Estate | Pass
Financing Receivable, Recorded Investment [Line Items]
Total Loans	537,572	349,625
Excluding Purchased Impaired | Multifamily Real Estate | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Total Loans	10,571	7,374
Excluding Purchased Impaired | Multifamily Real Estate | Substandard
Financing Receivable, Recorded Investment [Line Items]
Total Loans	0	0
Excluding Purchased Impaired | Multifamily Real Estate | Doubtful
Financing Receivable, Recorded Investment [Line Items]
Total Loans	0	0
Excluding Purchased Impaired | Commercial and Industrial
Financing Receivable, Recorded Investment [Line Items]
Total Loans	1,314,979	611,615
Excluding Purchased Impaired | Commercial and Industrial | Pass
Financing Receivable, Recorded Investment [Line Items]
Total Loans	1,273,549	595,923
Excluding Purchased Impaired | Commercial and Industrial | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Total Loans	34,864	13,533
Excluding Purchased Impaired | Commercial and Industrial | Substandard
Financing Receivable, Recorded Investment [Line Items]
Total Loans	6,566	2,159
Excluding Purchased Impaired | Commercial and Industrial | Doubtful
Financing Receivable, Recorded Investment [Line Items]
Total Loans	0	0
Excluding Purchased Impaired | Residential 1-4 Family - Commercial
Financing Receivable, Recorded Investment [Line Items]
Total Loans	700,043	602,981
Excluding Purchased Impaired | Residential 1-4 Family - Commercial | Pass
Financing Receivable, Recorded Investment [Line Items]
Total Loans	677,109	587,169
Excluding Purchased Impaired | Residential 1-4 Family - Commercial | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Total Loans	17,086	12,117
Excluding Purchased Impaired | Residential 1-4 Family - Commercial | Substandard
Financing Receivable, Recorded Investment [Line Items]
Total Loans	5,848	3,650
Excluding Purchased Impaired | Residential 1-4 Family - Commercial | Doubtful
Financing Receivable, Recorded Investment [Line Items]
Total Loans	0	45
Excluding Purchased Impaired | Residential 1-4 Family - Mortgage
Financing Receivable, Recorded Investment [Line Items]
Total Loans	583,812	481,957
Excluding Purchased Impaired | Residential 1-4 Family - Mortgage | Pass
Financing Receivable, Recorded Investment [Line Items]
Total Loans	554,192	470,646
Excluding Purchased Impaired | Residential 1-4 Family - Mortgage | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Total Loans	14,855	7,190
Excluding Purchased Impaired | Residential 1-4 Family - Mortgage | Substandard
Financing Receivable, Recorded Investment [Line Items]
Total Loans	14,765	1,642
Excluding Purchased Impaired | Residential 1-4 Family - Mortgage | Doubtful
Financing Receivable, Recorded Investment [Line Items]
Total Loans	0	2,479
Excluding Purchased Impaired | Auto
Financing Receivable, Recorded Investment [Line Items]
Total Loans	301,936	282,474
Excluding Purchased Impaired | Auto | Pass
Financing Receivable, Recorded Investment [Line Items]
Total Loans	296,907	278,063
Excluding Purchased Impaired | Auto | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Total Loans	3,590	4,131
Excluding Purchased Impaired | Auto | Substandard
Financing Receivable, Recorded Investment [Line Items]
Total Loans	1,439	119
Excluding Purchased Impaired | Auto | Doubtful
Financing Receivable, Recorded Investment [Line Items]
Total Loans	0	161
Excluding Purchased Impaired | HELOC
Financing Receivable, Recorded Investment [Line Items]
Total Loans	608,268	536,571
Excluding Purchased Impaired | HELOC | Pass
Financing Receivable, Recorded Investment [Line Items]
Total Loans	598,444	531,358
Excluding Purchased Impaired | HELOC | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Total Loans	6,316	3,867
Excluding Purchased Impaired | HELOC | Substandard
Financing Receivable, Recorded Investment [Line Items]
Total Loans	3,508	857
Excluding Purchased Impaired | HELOC | Doubtful
Financing Receivable, Recorded Investment [Line Items]
Total Loans	0	489
Excluding Purchased Impaired | Consumer and all other
Financing Receivable, Recorded Investment [Line Items]
Total Loans	620,862	647,789
Excluding Purchased Impaired | Consumer and all other | Pass
Financing Receivable, Recorded Investment [Line Items]
Total Loans	618,730	645,187
Excluding Purchased Impaired | Consumer and all other | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Total Loans	1,411	1,758
Excluding Purchased Impaired | Consumer and all other | Substandard
Financing Receivable, Recorded Investment [Line Items]
Total Loans	721	781
Excluding Purchased Impaired | Consumer and all other | Doubtful
Financing Receivable, Recorded Investment [Line Items]
Total Loans	$ 0	$ 63