LOANS AND ALLOWANCE FOR LOAN LOSSES (PCI Loan Portfolios by Segment and Delinquency Status) (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	$ 11,776,128	$ 9,537,156
Total Loans	11,952,310	9,716,207
Construction and Land Development
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	1,305,024	1,177,204
Total Loans	1,326,679	1,194,821
Commercial Real Estate - Owner Occupied
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	1,883,881	1,294,975
Total Loans	1,921,464	1,337,345
Commercial Real Estate - Non-Owner Occupied
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	2,944,927	2,447,907
Total Loans	2,970,453	2,467,410
Multifamily Real Estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	590,745	547,997
Total Loans	591,431	548,231
Commercial & Industrial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	1,858,429	1,309,581
Total Loans	1,866,625	1,317,135
Residential 1-4 Family - Commercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	790,458	687,957
Total Loans	815,309	713,750
Residential 1-4 Family - Mortgage
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	830,642	556,907
Total Loans	865,502	600,578
Auto
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	297,499	297,442
Total Loans	300,631	301,943
HELOC
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	658,263	600,055
Total Loans	672,087	613,383
Consumer
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	392,478	376,057
Total Loans	397,491	379,694
Other Commercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	223,782	241,074
Total Loans	224,638	241,917
Purchased Impaired
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	79,829	71,213
Total Loans	99,932	90,221
Purchased Impaired | 30 To 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	7,658	4,264
Purchased Impaired | Greater than 90 Days
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	12,445	14,744
Purchased Impaired | Construction and Land Development
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	11,123	7,122
Total Loans	12,600	8,654
Purchased Impaired | Construction and Land Development | 30 To 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	220	108
Purchased Impaired | Construction and Land Development | Greater than 90 Days
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	1,257	1,424
Purchased Impaired | Commercial Real Estate - Owner Occupied
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	21,492	20,705
Total Loans	26,836	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	453	658
Purchased Impaired | Commercial Real Estate - Owner Occupied | Greater than 90 Days
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	4,891	4,281
Purchased Impaired | Commercial Real Estate - Non-Owner Occupied
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	16,931	15,464
Total Loans	18,850	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	146	61
Purchased Impaired | Commercial Real Estate - Non-Owner Occupied | Greater than 90 Days
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	1,773	1,810
Purchased Impaired | Multifamily Real Estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	90	88
Total Loans	90	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	2,601	1,017
Total Loans	4,159	2,156
Purchased Impaired | Commercial & Industrial | 30 To 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	275	47
Purchased Impaired | Commercial & Industrial | Greater than 90 Days
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	1,283	1,092
Purchased Impaired | Residential 1-4 Family - Commercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	9,732	9,312
Total Loans	13,693	13,707
Purchased Impaired | Residential 1-4 Family - Commercial | 30 To 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	2,990	931
Purchased Impaired | Residential 1-4 Family - Commercial | Greater than 90 Days
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	971	3,464
Purchased Impaired | Residential 1-4 Family - Mortgage
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	12,261	12,455
Total Loans	17,180	16,766
Purchased Impaired | Residential 1-4 Family - Mortgage | 30 To 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	2,761	1,899
Purchased Impaired | Residential 1-4 Family - Mortgage | Greater than 90 Days
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	2,158	2,412
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	4,225	4,365
Total Loans	5,138	5,115
Purchased Impaired | HELOC | 30 To 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	808	498
Purchased Impaired | HELOC | Greater than 90 Days
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	105	252
Purchased Impaired | Consumer
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	681	18
Total Loans	693	32
Purchased Impaired | Consumer | 30 To 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	5	5
Purchased Impaired | Consumer | Greater than 90 Days
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	7	9
Purchased Impaired | Other Commercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	686	660
Total Loans	686	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