LOANS AND ALLOWANCE FOR LOAN LOSSES (Loans Receivables Related Risk Rating Excluding Purchased Impaired Loans) (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Financing Receivable, Recorded Investment [Line Items]
Total Loans	$ 9,290,259	$ 7,141,552
Construction and Land Development
Financing Receivable, Recorded Investment [Line Items]
Total Loans	1,250,448	948,791
Commercial Real Estate - Owner Occupied
Financing Receivable, Recorded Investment [Line Items]
Total Loans	1,293,791	943,933
Commercial Real Estate - Non-Owner Occupied
Financing Receivable, Recorded Investment [Line Items]
Total Loans	2,318,589	1,713,659
Multifamily Real Estate
Financing Receivable, Recorded Investment [Line Items]
Total Loans	541,730	357,079
Commercial & Industrial
Financing Receivable, Recorded Investment [Line Items]
Total Loans	1,093,771	612,023
Residential 1-4 Family - Commercial
Financing Receivable, Recorded Investment [Line Items]
Total Loans	723,945	612,395
Residential 1-4 Family - Mortgage
Financing Receivable, Recorded Investment [Line Items]
Total Loans	607,155	485,690
Auto
Financing Receivable, Recorded Investment [Line Items]
Total Loans	296,706	282,474
HELOC
Financing Receivable, Recorded Investment [Line Items]
Total Loans	626,916	537,521
Consumer and all other
Financing Receivable, Recorded Investment [Line Items]
Total Loans	537,208	647,987
Excluding Purchased Impaired
Financing Receivable, Recorded Investment [Line Items]
Total Loans	9,188,735	7,102,531
Excluding Purchased Impaired | Pass
Financing Receivable, Recorded Investment [Line Items]
Total Loans	8,908,024	6,880,526
Excluding Purchased Impaired | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Total Loans	228,767	184,654
Excluding Purchased Impaired | Substandard
Financing Receivable, Recorded Investment [Line Items]
Total Loans	51,726	34,114
Excluding Purchased Impaired | Doubtful
Financing Receivable, Recorded Investment [Line Items]
Total Loans	218	3,237
Excluding Purchased Impaired | Construction and Land Development
Financing Receivable, Recorded Investment [Line Items]
Total Loans	1,245,265	945,953
Excluding Purchased Impaired | Construction and Land Development | Pass
Financing Receivable, Recorded Investment [Line Items]
Total Loans	1,175,380	869,111
Excluding Purchased Impaired | Construction and Land Development | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Total Loans	57,960	62,517
Excluding Purchased Impaired | Construction and Land Development | Substandard
Financing Receivable, Recorded Investment [Line Items]
Total Loans	11,925	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	1,267,071	929,143
Excluding Purchased Impaired | Commercial Real Estate - Owner Occupied | Pass
Financing Receivable, Recorded Investment [Line Items]
Total Loans	1,205,921	872,130
Excluding Purchased Impaired | Commercial Real Estate - Owner Occupied | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Total Loans	50,989	52,268
Excluding Purchased Impaired | Commercial Real Estate - Owner Occupied | Substandard
Financing Receivable, Recorded Investment [Line Items]
Total Loans	10,161	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	2,293,909	1,707,049
Excluding Purchased Impaired | Commercial Real Estate - Non-Owner Occupied | Pass
Financing Receivable, Recorded Investment [Line Items]
Total Loans	2,245,538	1,681,314
Excluding Purchased Impaired | Commercial Real Estate - Non-Owner Occupied | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Total Loans	41,367	19,899
Excluding Purchased Impaired | Commercial Real Estate - Non-Owner Occupied | Substandard
Financing Receivable, Recorded Investment [Line Items]
Total Loans	7,004	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	541,646	356,999
Excluding Purchased Impaired | Multifamily Real Estate | Pass
Financing Receivable, Recorded Investment [Line Items]
Total Loans	526,392	349,625
Excluding Purchased Impaired | Multifamily Real Estate | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Total Loans	15,254	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 & Industrial
Financing Receivable, Recorded Investment [Line Items]
Total Loans	1,091,920	611,615
Excluding Purchased Impaired | Commercial & Industrial | Pass
Financing Receivable, Recorded Investment [Line Items]
Total Loans	1,056,472	595,923
Excluding Purchased Impaired | Commercial & Industrial | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Total Loans	33,041	13,533
Excluding Purchased Impaired | Commercial & Industrial | Substandard
Financing Receivable, Recorded Investment [Line Items]
Total Loans	2,407	2,159
Excluding Purchased Impaired | Commercial & 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	706,718	602,981
Excluding Purchased Impaired | Residential 1-4 Family - Commercial | Pass
Financing Receivable, Recorded Investment [Line Items]
Total Loans	686,817	587,169
Excluding Purchased Impaired | Residential 1-4 Family - Commercial | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Total Loans	15,161	12,117
Excluding Purchased Impaired | Residential 1-4 Family - Commercial | Substandard
Financing Receivable, Recorded Investment [Line Items]
Total Loans	4,740	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	589,153	481,957
Excluding Purchased Impaired | Residential 1-4 Family - Mortgage | Pass
Financing Receivable, Recorded Investment [Line Items]
Total Loans	572,050	470,646
Excluding Purchased Impaired | Residential 1-4 Family - Mortgage | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Total Loans	6,353	7,190
Excluding Purchased Impaired | Residential 1-4 Family - Mortgage | Substandard
Financing Receivable, Recorded Investment [Line Items]
Total Loans	10,564	1,642
Excluding Purchased Impaired | Residential 1-4 Family - Mortgage | Doubtful
Financing Receivable, Recorded Investment [Line Items]
Total Loans	186	2,479
Excluding Purchased Impaired | Auto
Financing Receivable, Recorded Investment [Line Items]
Total Loans	296,695	282,474
Excluding Purchased Impaired | Auto | Pass
Financing Receivable, Recorded Investment [Line Items]
Total Loans	293,409	278,063
Excluding Purchased Impaired | Auto | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Total Loans	2,531	4,131
Excluding Purchased Impaired | Auto | Substandard
Financing Receivable, Recorded Investment [Line Items]
Total Loans	737	119
Excluding Purchased Impaired | Auto | Doubtful
Financing Receivable, Recorded Investment [Line Items]
Total Loans	18	161
Excluding Purchased Impaired | HELOC
Financing Receivable, Recorded Investment [Line Items]
Total Loans	620,026	536,571
Excluding Purchased Impaired | HELOC | Pass
Financing Receivable, Recorded Investment [Line Items]
Total Loans	613,491	531,358
Excluding Purchased Impaired | HELOC | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Total Loans	3,044	3,867
Excluding Purchased Impaired | HELOC | Substandard
Financing Receivable, Recorded Investment [Line Items]
Total Loans	3,491	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	536,332	647,789
Excluding Purchased Impaired | Consumer and all other | Pass
Financing Receivable, Recorded Investment [Line Items]
Total Loans	532,554	645,187
Excluding Purchased Impaired | Consumer and all other | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Total Loans	3,067	1,758
Excluding Purchased Impaired | Consumer and all other | Substandard
Financing Receivable, Recorded Investment [Line Items]
Total Loans	697	781
Excluding Purchased Impaired | Consumer and all other | Doubtful
Financing Receivable, Recorded Investment [Line Items]
Total Loans	$ 14	$ 63