LOANS AND ALLOWANCE FOR LOAN LOSSES (PCI Loan Portfolios by Segment and Delinquency Status) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	$ 12,419,378	$ 9,537,156
Total Loans	12,610,936	9,716,207
Purchased Impaired
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	70,267	71,213
Total Loans	86,681	90,221
Construction and Land Development
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	1,231,043	1,177,204
Total Loans	1,250,924	1,194,821
Construction and Land Development | Purchased Impaired
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	10,465	7,122
Total Loans	10,944	8,654
Commercial Real Estate - Owner Occupied
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	2,001,074	1,294,975
Total Loans	2,041,243	1,337,345
Commercial Real Estate - Owner Occupied | Purchased Impaired
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	20,074	20,705
Total Loans	27,438	25,644
Commercial Real Estate - Non-Owner Occupied
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	3,269,244	2,447,907
Total Loans	3,286,098	2,467,410
Commercial Real Estate - Non-Owner Occupied | Purchased Impaired
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	12,730	15,464
Total Loans	14,565	17,335
Multifamily Real Estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	632,952	547,997
Total Loans	633,743	548,231
Multifamily Real Estate | Purchased Impaired
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	94	88
Total Loans	94	88
Commercial and Industrial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	2,099,974	1,309,581
Total Loans	2,114,033	1,317,135
Commercial and Industrial | Purchased Impaired
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	590	1,017
Total Loans	1,579	2,156
Residential 1-4 Family - Commercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	703,471	614,732
Total Loans	724,337	640,419
Residential 1-4 Family - Commercial | Purchased Impaired
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	9,667	9,276
Total Loans	12,205	13,601
Residential 1-4 Family - Consumer
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	842,667	630,132
Total Loans	890,503	673,909
Residential 1-4 Family - Consumer | Purchased Impaired
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	12,005	12,491
Total Loans	14,713	16,872
Residential 1-4 Family - Revolving
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	637,966	600,055
Total Loans	659,504	613,383
Residential 1-4 Family - Revolving | Purchased Impaired
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	3,635	4,365
Total Loans	4,127	5,115
Auto
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	346,819	297,442
Total Loans	350,419	301,943
Auto | Purchased Impaired
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	4	7
Total Loans	4	7
Consumer
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	367,794	376,057
Total Loans	372,853	379,694
Consumer | Purchased Impaired
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	659	18
Total Loans	668	32
Other Commercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	286,374	241,074
Total Loans	287,279	241,917
Other Commercial | Purchased Impaired
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	344	660
Total Loans	344	717
30 To 89 Days Past Due | Purchased Impaired
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	3,221	4,264
30 To 89 Days Past Due | Construction and Land Development | Purchased Impaired
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	136	108
30 To 89 Days Past Due | Commercial Real Estate - Owner Occupied | Purchased Impaired
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	480	658
30 To 89 Days Past Due | Commercial Real Estate - Non-Owner Occupied | Purchased Impaired
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	848	61
30 To 89 Days Past Due | Multifamily Real Estate | Purchased Impaired
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	0	0
30 To 89 Days Past Due | Commercial and Industrial | Purchased Impaired
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	0	47
30 To 89 Days Past Due | Residential 1-4 Family - Commercial | Purchased Impaired
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	543	871
30 To 89 Days Past Due | Residential 1-4 Family - Consumer | Purchased Impaired
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	927	1,959
30 To 89 Days Past Due | Residential 1-4 Family - Revolving | Purchased Impaired
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	287	498
30 To 89 Days Past Due | Auto | Purchased Impaired
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	0	0
30 To 89 Days Past Due | Consumer | Purchased Impaired
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	0	5
30 To 89 Days Past Due | Other Commercial | Purchased Impaired
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	0	57
Greater Than 90 Days | Purchased Impaired
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	13,193	14,744
Greater Than 90 Days | Construction and Land Development | Purchased Impaired
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	343	1,424
Greater Than 90 Days | Commercial Real Estate - Owner Occupied | Purchased Impaired
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	6,884	4,281
Greater Than 90 Days | Commercial Real Estate - Non-Owner Occupied | Purchased Impaired
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	987	1,810
Greater Than 90 Days | Multifamily Real Estate | Purchased Impaired
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	0	0
Greater Than 90 Days | Commercial and Industrial | Purchased Impaired
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	989	1,092
Greater Than 90 Days | Residential 1-4 Family - Commercial | Purchased Impaired
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	1,995	3,454
Greater Than 90 Days | Residential 1-4 Family - Consumer | Purchased Impaired
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	1,781	2,422
Greater Than 90 Days | Residential 1-4 Family - Revolving | Purchased Impaired
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	205	252
Greater Than 90 Days | Auto | Purchased Impaired
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	0	0
Greater Than 90 Days | Consumer | Purchased Impaired
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	9	9
Greater Than 90 Days | Other Commercial | Purchased Impaired
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	$ 0	$ 0