LOANS AND ALLOWANCE FOR LOAN LOSSES (PCI Loan Portfolios by Segment and Delinquency Status) (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	$ 12,132,081	$ 9,537,156
Total Loans	12,306,997	9,716,207
Construction and Land Development
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	1,183,393	1,177,204
Total Loans	1,201,149	1,194,821
Commercial Real Estate - Owner Occupied
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	1,938,003	1,294,975
Total Loans	1,979,052	1,337,345
Commercial Real Estate - Non-Owner Occupied
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	3,173,243	2,447,907
Total Loans	3,198,580	2,467,410
Multifamily Real Estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	658,370	547,997
Total Loans	659,946	548,231
Commercial & Industrial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	2,048,996	1,309,581
Total Loans	2,058,133	1,317,135
Residential 1-4 Family - Commercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	699,230	614,732
Total Loans	721,185	640,419
Residential 1-4 Family - Consumer
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	879,452	630,132
Total Loans	913,245	673,909
Auto
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	325,468	297,442
Total Loans	328,456	301,943
HELOC
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	646,661	600,055
Total Loans	660,963	613,383
Consumer
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	381,253	376,057
Total Loans	386,848	379,694
Other Commercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	198,012	241,074
Total Loans	199,440	241,917
Purchased Impaired
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	79,092	71,213
Total Loans	89,735	90,221
Purchased Impaired | 30 To 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	2,266	4,264
Purchased Impaired | Greater than 90 Days
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	8,377	14,744
Purchased Impaired | Construction and Land Development
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	7,862	7,122
Total Loans	8,387	8,654
Purchased Impaired | Construction and Land Development | 30 To 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	126	108
Purchased Impaired | Construction and Land Development | Greater than 90 Days
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	399	1,424
Purchased Impaired | Commercial Real Estate - Owner Occupied
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	24,029	20,705
Total Loans	27,817	25,644
Purchased Impaired | Commercial Real Estate - Owner Occupied | 30 To 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	526	658
Purchased Impaired | Commercial Real Estate - Owner Occupied | Greater than 90 Days
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	3,262	4,281
Purchased Impaired | Commercial Real Estate - Non-Owner Occupied
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	16,168	15,464
Total Loans	17,285	17,335
Purchased Impaired | Commercial Real Estate - Non-Owner Occupied | 30 To 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	137	61
Purchased Impaired | Commercial Real Estate - Non-Owner Occupied | Greater than 90 Days
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	980	1,810
Purchased Impaired | Multifamily Real Estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	93	88
Total Loans	93	88
Purchased Impaired | Multifamily Real Estate | 30 To 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	0	0
Purchased Impaired | Multifamily Real Estate | Greater than 90 Days
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	0	0
Purchased Impaired | Commercial & Industrial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	2,219	1,017
Total Loans	3,262	2,156
Purchased Impaired | Commercial & Industrial | 30 To 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due		47
Purchased Impaired | Commercial & Industrial | Greater than 90 Days
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	1,043	1,092
Purchased Impaired | Residential 1-4 Family - Commercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	11,337	9,276
Total Loans	12,237	13,601
Purchased Impaired | Residential 1-4 Family - Commercial | 30 To 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	421	871
Purchased Impaired | Residential 1-4 Family - Commercial | Greater than 90 Days
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	479	3,454
Purchased Impaired | Residential 1-4 Family - Consumer
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	12,221	12,491
Total Loans	14,977	16,872
Purchased Impaired | Residential 1-4 Family - Consumer | 30 To 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	844	1,959
Purchased Impaired | Residential 1-4 Family - Consumer | Greater than 90 Days
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	1,912	2,422
Purchased Impaired | Auto
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	7	7
Total Loans	7	7
Purchased Impaired | Auto | 30 To 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	0	0
Purchased Impaired | Auto | Greater than 90 Days
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	0	0
Purchased Impaired | HELOC
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	3,780	4,365
Total Loans	4,275	5,115
Purchased Impaired | HELOC | 30 To 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	208	498
Purchased Impaired | HELOC | Greater than 90 Days
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	287	252
Purchased Impaired | Consumer
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	663	18
Total Loans	682	32
Purchased Impaired | Consumer | 30 To 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	4	5
Purchased Impaired | Consumer | Greater than 90 Days
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	15	9
Purchased Impaired | Other Commercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	713	660
Total Loans	713	717
Purchased Impaired | Other Commercial | 30 To 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	0	57
Purchased Impaired | Other Commercial | Greater than 90 Days
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	$ 0	$ 0