LOANS AND ALLOWANCE FOR LOAN LOSSES (Summary of Aging of the Loan Portfolio by Class) (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Jan. 01, 2020	Dec. 31, 2019
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	$ 14,293,262		$ 12,419,378
Greater Than 90 Days and Still Accruing	15,661		13,396
Nonaccrual	39,023	$ 45,204	28,232
Total Loans	14,383,215		12,610,936
30-59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	23,211		50,453
60-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	12,058		12,796
Purchased Impaired
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current			70,267
Total Loans	68,800		86,681
Purchased Impaired | 30-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due			3,221
Purchased Impaired | 90+ Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due			13,193
Construction and Land Development
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	1,200,729		1,231,043
Greater Than 90 Days and Still Accruing	93		189
Nonaccrual	3,520	4,060	3,703
Total Loans	1,207,190		1,250,924
Construction and Land Development | 30-59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	2,625		4,563
Construction and Land Development | 60-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	223		482
Construction and Land Development | Purchased Impaired
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current			10,465
Total Loans			10,944
Construction and Land Development | Purchased Impaired | 30-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due			136
Construction and Land Development | Purchased Impaired | 90+ Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due			343
Commercial Real Estate - Owner Occupied
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	2,090,106		2,001,074
Greater Than 90 Days and Still Accruing	1,726		1,062
Nonaccrual	9,267	13,889	6,003
Total Loans	2,107,333		2,041,243
Commercial Real Estate - Owner Occupied | 30-59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	4,924		3,482
Commercial Real Estate - Owner Occupied | 60-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	1,310		2,184
Commercial Real Estate - Owner Occupied | Purchased Impaired
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current			20,074
Total Loans			27,438
Commercial Real Estate - Owner Occupied | Purchased Impaired | 30-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due			480
Commercial Real Estate - Owner Occupied | Purchased Impaired | 90+ Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due			6,884
Commercial Real Estate - Non-Owner Occupied
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	3,493,107		3,269,244
Greater Than 90 Days and Still Accruing	168		1,451
Nonaccrual	1,992	1,368	381
Total Loans	3,497,929		3,286,098
Commercial Real Estate - Non-Owner Occupied | 30-59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	1,291		457
Commercial Real Estate - Non-Owner Occupied | 60-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	1,371		0
Commercial Real Estate - Non-Owner Occupied | Purchased Impaired
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current			12,730
Total Loans			14,565
Commercial Real Estate - Non-Owner Occupied | Purchased Impaired | 30-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due			848
Commercial Real Estate - Non-Owner Occupied | Purchased Impaired | 90+ Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due			987
Multifamily Real Estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	731,190		632,952
Greater Than 90 Days and Still Accruing	359		474
Nonaccrual	33	0	0
Total Loans	731,582		633,743
Multifamily Real Estate | 30-59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due			223
Multifamily Real Estate | 60-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due			0
Multifamily Real Estate | Purchased Impaired
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current			94
Total Loans			94
Multifamily Real Estate | Purchased Impaired | 30-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due			0
Multifamily Real Estate | Purchased Impaired | 90+ Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due			0
Commercial and Industrial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	3,528,283		2,099,974
Greater Than 90 Days and Still Accruing	604		449
Nonaccrual	1,592	3,037	1,735
Total Loans	3,536,249		2,114,033
Commercial and Industrial | 30-59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	4,322		8,698
Commercial and Industrial | 60-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	1,448		1,598
Commercial and Industrial | Purchased Impaired
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current			590
Total Loans			1,579
Commercial and Industrial | Purchased Impaired | 90+ Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due			989
Residential 1-4 Family - Commercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	683,730		703,471
Greater Than 90 Days and Still Accruing	5,298		674
Nonaccrual	5,743	6,492	4,301
Total Loans	696,944		724,337
Residential 1-4 Family - Commercial | 30-59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	1,236		1,479
Residential 1-4 Family - Commercial | 60-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	937		2,207
Residential 1-4 Family - Commercial | Purchased Impaired
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current			9,667
Total Loans			12,205
Residential 1-4 Family - Commercial | Purchased Impaired | 30-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due			543
Residential 1-4 Family - Commercial | Purchased Impaired | 90+ Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due			1,995
Residential 1-4 Family - Consumer
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	806,055		842,667
Greater Than 90 Days and Still Accruing	4,495		4,515
Nonaccrual	12,620	13,117	9,292
Total Loans	830,144		890,503
Residential 1-4 Family - Consumer | 30-59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	2,998		16,244
Total Loans	2,998
Residential 1-4 Family - Consumer | 60-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	3,976		3,072
Total Loans	3,976
Residential 1-4 Family - Consumer | 90+ Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	4,495
Residential 1-4 Family - Consumer | Purchased Impaired
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current			12,005
Total Loans			14,713
Residential 1-4 Family - Consumer | Purchased Impaired | 30-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due			927
Residential 1-4 Family - Consumer | Purchased Impaired | 90+ Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due			1,781
Residential 1-4 Family - Revolving
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	608,570		637,966
Greater Than 90 Days and Still Accruing	2,276		3,357
Nonaccrual	3,664	2,490	2,080
Total Loans	618,320		659,504
Residential 1-4 Family - Revolving | 30-59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	2,669		10,190
Total Loans	2,669
Residential 1-4 Family - Revolving | 60-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	1,141		1,784
Total Loans	1,141
Residential 1-4 Family - Revolving | 90+ Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	2,276
Residential 1-4 Family - Revolving | Purchased Impaired
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current			3,635
Total Loans			4,127
Residential 1-4 Family - Revolving | Purchased Impaired | 30-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due			287
Residential 1-4 Family - Revolving | Purchased Impaired | 90+ Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due			205
Auto
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	384,619		346,819
Greater Than 90 Days and Still Accruing	315		272
Nonaccrual	517	565	563
Total Loans	387,417		350,419
Auto | 30-59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	1,513		2,525
Total Loans	1,513
Auto | 60-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	453		236
Total Loans	453
Auto | 90+ Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	315
Auto | Purchased Impaired
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current			4
Total Loans			4
Consumer
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	273,829		367,794
Greater Than 90 Days and Still Accruing	327		953
Nonaccrual	75	88	77
Total Loans	276,023		372,853
Consumer | 30-59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	1,020		2,128
Total Loans	1,020
Consumer | 60-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	772		1,233
Total Loans	772
Consumer | 90+ Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	327
Consumer | Purchased Impaired
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current			659
Total Loans			668
Consumer | Purchased Impaired | 90+ Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due			9
Other Commercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	493,044		286,374
Greater Than 90 Days and Still Accruing	0		0
Nonaccrual		$ 98	97
Total Loans	494,084		287,279
Other Commercial | 30-59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	613		464
Other Commercial | 60-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	$ 427		0
Other Commercial | Purchased Impaired
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current			344
Total Loans			344
Other Commercial | Purchased Impaired | 30-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due			0
Other Commercial | Purchased Impaired | 90+ Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due			$ 0