LOANS AND ALLOWANCE FOR LOAN LOSSES (Loans Receivables Related Risk Rating Excluding Purchased Impaired Loans) (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Financing Receivable, Recorded Investment [Line Items]
Total Loans	$ 12,220,514	$ 9,716,207
Construction and Land Development
Financing Receivable, Recorded Investment [Line Items]
Total Loans	1,267,712	1,194,821
Commercial Real Estate - Owner Occupied
Financing Receivable, Recorded Investment [Line Items]
Total Loans	1,966,776	1,337,345
Commercial Real Estate - Non-Owner Occupied
Financing Receivable, Recorded Investment [Line Items]
Total Loans	3,104,823	2,467,410
Multifamily Real Estate
Financing Receivable, Recorded Investment [Line Items]
Total Loans	602,115	548,231
Commercial & Industrial
Financing Receivable, Recorded Investment [Line Items]
Total Loans	2,032,799	1,317,135
Residential 1-4 Family - Commercial
Financing Receivable, Recorded Investment [Line Items]
Total Loans	801,703	713,750
Residential 1-4 Family - Mortgage
Financing Receivable, Recorded Investment [Line Items]
Total Loans	850,063	600,578
Auto
Financing Receivable, Recorded Investment [Line Items]
Total Loans	311,858	301,943
HELOC
Financing Receivable, Recorded Investment [Line Items]
Total Loans	660,621	613,383
Consumer
Financing Receivable, Recorded Investment [Line Items]
Total Loans	383,653	379,694
Other Commercial
Financing Receivable, Recorded Investment [Line Items]
Total Loans	238,391	241,917
Excluding Purchased Impaired
Financing Receivable, Recorded Investment [Line Items]
Total Loans	12,119,213	9,625,986
Excluding Purchased Impaired | Pass
Financing Receivable, Recorded Investment [Line Items]
Total Loans	11,761,202	9,344,002
Excluding Purchased Impaired | Watch & Special Mention
Financing Receivable, Recorded Investment [Line Items]
Total Loans	286,542	201,174
Excluding Purchased Impaired | Substandard
Financing Receivable, Recorded Investment [Line Items]
Total Loans	71,469	80,810
Excluding Purchased Impaired | Doubtful
Financing Receivable, Recorded Investment [Line Items]
Total Loans	0	0
Excluding Purchased Impaired | Construction and Land Development
Financing Receivable, Recorded Investment [Line Items]
Total Loans	1,255,531	1,186,167
Excluding Purchased Impaired | Construction and Land Development | Pass
Financing Receivable, Recorded Investment [Line Items]
Total Loans	1,204,655	1,130,577
Excluding Purchased Impaired | Construction and Land Development | Watch & Special Mention
Financing Receivable, Recorded Investment [Line Items]
Total Loans	43,268	43,894
Excluding Purchased Impaired | Construction and Land Development | Substandard
Financing Receivable, Recorded Investment [Line Items]
Total Loans	7,608	11,696
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	1,934,148	1,311,701
Excluding Purchased Impaired | Commercial Real Estate - Owner Occupied | Pass
Financing Receivable, Recorded Investment [Line Items]
Total Loans	1,848,333	1,231,422
Excluding Purchased Impaired | Commercial Real Estate - Owner Occupied | Watch & Special Mention
Financing Receivable, Recorded Investment [Line Items]
Total Loans	65,257	50,939
Excluding Purchased Impaired | Commercial Real Estate - Owner Occupied | Substandard
Financing Receivable, Recorded Investment [Line Items]
Total Loans	20,558	29,340
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	3,089,068	2,450,075
Excluding Purchased Impaired | Commercial Real Estate - Non-Owner Occupied | Pass
Financing Receivable, Recorded Investment [Line Items]
Total Loans	3,042,648	2,425,500
Excluding Purchased Impaired | Commercial Real Estate - Non-Owner Occupied | Watch & Special Mention
Financing Receivable, Recorded Investment [Line Items]
Total Loans	40,760	17,648
Excluding Purchased Impaired | Commercial Real Estate - Non-Owner Occupied | Substandard
Financing Receivable, Recorded Investment [Line Items]
Total Loans	5,660	6,927
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	602,023	548,143
Excluding Purchased Impaired | Multifamily Real Estate | Pass
Financing Receivable, Recorded Investment [Line Items]
Total Loans	586,626	537,572
Excluding Purchased Impaired | Multifamily Real Estate | Watch & Special Mention
Financing Receivable, Recorded Investment [Line Items]
Total Loans	15,397	10,571
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	2,028,869	1,314,979
Excluding Purchased Impaired | Commercial & Industrial | Pass
Financing Receivable, Recorded Investment [Line Items]
Total Loans	1,945,547	1,273,549
Excluding Purchased Impaired | Commercial & Industrial | Watch & Special Mention
Financing Receivable, Recorded Investment [Line Items]
Total Loans	79,232	34,864
Excluding Purchased Impaired | Commercial & Industrial | Substandard
Financing Receivable, Recorded Investment [Line Items]
Total Loans	4,090	6,566
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	789,028	700,043
Excluding Purchased Impaired | Residential 1-4 Family - Commercial | Pass
Financing Receivable, Recorded Investment [Line Items]
Total Loans	755,438	677,109
Excluding Purchased Impaired | Residential 1-4 Family - Commercial | Watch & Special Mention
Financing Receivable, Recorded Investment [Line Items]
Total Loans	26,284	17,086
Excluding Purchased Impaired | Residential 1-4 Family - Commercial | Substandard
Financing Receivable, Recorded Investment [Line Items]
Total Loans	7,306	5,848
Excluding Purchased Impaired | Residential 1-4 Family - Commercial | Doubtful
Financing Receivable, Recorded Investment [Line Items]
Total Loans	0	0
Excluding Purchased Impaired | Residential 1-4 Family - Mortgage
Financing Receivable, Recorded Investment [Line Items]
Total Loans	832,242	583,812
Excluding Purchased Impaired | Residential 1-4 Family - Mortgage | Pass
Financing Receivable, Recorded Investment [Line Items]
Total Loans	808,797	554,192
Excluding Purchased Impaired | Residential 1-4 Family - Mortgage | Watch & Special Mention
Financing Receivable, Recorded Investment [Line Items]
Total Loans	6,036	14,855
Excluding Purchased Impaired | Residential 1-4 Family - Mortgage | Substandard
Financing Receivable, Recorded Investment [Line Items]
Total Loans	17,409	14,765
Excluding Purchased Impaired | Residential 1-4 Family - Mortgage | Doubtful
Financing Receivable, Recorded Investment [Line Items]
Total Loans	0	0
Excluding Purchased Impaired | Auto
Financing Receivable, Recorded Investment [Line Items]
Total Loans	311,851	301,936
Excluding Purchased Impaired | Auto | Pass
Financing Receivable, Recorded Investment [Line Items]
Total Loans	307,921	296,907
Excluding Purchased Impaired | Auto | Watch & Special Mention
Financing Receivable, Recorded Investment [Line Items]
Total Loans	2,181	3,590
Excluding Purchased Impaired | Auto | Substandard
Financing Receivable, Recorded Investment [Line Items]
Total Loans	1,749	1,439
Excluding Purchased Impaired | Auto | Doubtful
Financing Receivable, Recorded Investment [Line Items]
Total Loans	0	0
Excluding Purchased Impaired | HELOC
Financing Receivable, Recorded Investment [Line Items]
Total Loans	655,752	608,268
Excluding Purchased Impaired | HELOC | Pass
Financing Receivable, Recorded Investment [Line Items]
Total Loans	643,778	598,444
Excluding Purchased Impaired | HELOC | Watch & Special Mention
Financing Receivable, Recorded Investment [Line Items]
Total Loans	5,418	6,316
Excluding Purchased Impaired | HELOC | Substandard
Financing Receivable, Recorded Investment [Line Items]
Total Loans	6,556	3,508
Excluding Purchased Impaired | HELOC | Doubtful
Financing Receivable, Recorded Investment [Line Items]
Total Loans	0	0
Excluding Purchased Impaired | Consumer
Financing Receivable, Recorded Investment [Line Items]
Total Loans	382,964	379,662
Excluding Purchased Impaired | Consumer | Pass
Financing Receivable, Recorded Investment [Line Items]
Total Loans	381,478	378,873
Excluding Purchased Impaired | Consumer | Watch & Special Mention
Financing Receivable, Recorded Investment [Line Items]
Total Loans	1,121	547
Excluding Purchased Impaired | Consumer | Substandard
Financing Receivable, Recorded Investment [Line Items]
Total Loans	365	242
Excluding Purchased Impaired | Consumer | Doubtful
Financing Receivable, Recorded Investment [Line Items]
Total Loans	0	0
Excluding Purchased Impaired | Other Commercial
Financing Receivable, Recorded Investment [Line Items]
Total Loans	237,737	241,200
Excluding Purchased Impaired | Other Commercial | Pass
Financing Receivable, Recorded Investment [Line Items]
Total Loans	235,981	239,857
Excluding Purchased Impaired | Other Commercial | Watch & Special Mention
Financing Receivable, Recorded Investment [Line Items]
Total Loans	1,588	864
Excluding Purchased Impaired | Other Commercial | Substandard
Financing Receivable, Recorded Investment [Line Items]
Total Loans	168	479
Excluding Purchased Impaired | Other Commercial | Doubtful
Financing Receivable, Recorded Investment [Line Items]
Total Loans	$ 0	$ 0