LOANS AND ALLOWANCE FOR LOAN LOSSES (Summary of Aging of the Loan Portfolio by Class) (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Jan. 01, 2021	Dec. 31, 2020	Jan. 01, 2020
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	$ 13,636,459		$ 13,929,049
Current, % of total loans	99.55%		99.34%
Greater Than 90 Days and Still Accruing	$ 8,746		$ 13,634
Greater than 90 Days and still Accruing, % of total loans	0.06%		0.10%
Nonaccrual	$ 36,399	$ 42,448	$ 42,448	$ 45,204
Nonaccrual, % of total loans	0.27%		0.30%
Total Loans	$ 13,697,929		$ 14,021,314
Total loans, % of total loans	100.00%		100.00%
30-59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	$ 9,499		$ 27,024
Past Due, % of total loans	0.07%		0.19%
60-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	$ 6,826		$ 9,159
Past Due, % of total loans	0.05%		0.07%
Construction and Land Development
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	$ 834,743		$ 920,276
Greater Than 90 Days and Still Accruing	186		0
Nonaccrual	2,685	3,072	3,072	4,060
Total Loans	838,722		925,798
Construction and Land Development | 30-59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	798		1,903
Construction and Land Development | 60-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	310		547
Commercial Real Estate - Owner Occupied
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	2,056,955		2,114,804
Greater Than 90 Days and Still Accruing	2,276		3,727
Nonaccrual	6,969	7,128	7,128	13,889
Total Loans	2,069,658		2,128,909
Commercial Real Estate - Owner Occupied | 30-59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	1,450		1,870
Commercial Real Estate - Owner Occupied | 60-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	2,008		1,380
Commercial Real Estate - Non-Owner Occupied
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	3,707,175		3,651,232
Greater Than 90 Days and Still Accruing	827		148
Nonaccrual	3,026	2,317	2,317	1,368
Total Loans	3,712,607		3,657,562
Commercial Real Estate - Non-Owner Occupied | 30-59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	1,501		2,144
Commercial Real Estate - Non-Owner Occupied | 60-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	78		1,721
Multifamily Real Estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	859,812		814,095
Greater Than 90 Days and Still Accruing	0		0
Nonaccrual	113	33	33	0
Total Loans	860,081		814,745
Multifamily Real Estate | 30-59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	156		617
Multifamily Real Estate | 60-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	0		0
Commercial and Industrial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	2,984,945		3,257,201
Greater Than 90 Days and Still Accruing	1,088		1,114
Nonaccrual	1,908	2,107	2,107	3,037
Total Loans	2,990,622		3,263,460
Commercial and Industrial | 30-59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	948		1,848
Commercial and Industrial | 60-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	1,733		1,190
Residential 1-4 Family - Commercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	631,251		657,351
Greater Than 90 Days and Still Accruing	759		1,560
Nonaccrual	4,200	9,993	9,993	6,492
Total Loans	637,485		671,949
Residential 1-4 Family - Commercial | 30-59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	710		2,227
Residential 1-4 Family - Commercial | 60-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	565		818
Residential 1-4 Family - Consumer
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	805,385		792,852
Greater Than 90 Days and Still Accruing	2,725		5,699
Nonaccrual	13,489	12,600	12,600	13,117
Total Loans	823,355		822,866
Residential 1-4 Family - Consumer | Current
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	805,385		792,852
Residential 1-4 Family - Consumer | 30-59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	764		10,182
Total Loans	764		10,182
Residential 1-4 Family - Consumer | 60-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	992		1,533
Total Loans	992		1,533
Residential 1-4 Family - Consumer | 90+ Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	2,725		5,699
Residential 1-4 Family - Consumer | Nonaccrual
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	13,489		12,600
Residential 1-4 Family - Revolving
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	553,130		587,522
Greater Than 90 Days and Still Accruing	561		826
Nonaccrual	3,726	4,629	4,629	2,490
Total Loans	559,014		596,996
Residential 1-4 Family - Revolving | Current
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	553,130		587,522
Residential 1-4 Family - Revolving | 30-59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	919		2,975
Total Loans	919		2,975
Residential 1-4 Family - Revolving | 60-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	678		1,044
Total Loans	678		1,044
Residential 1-4 Family - Revolving | 90+ Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	561		826
Residential 1-4 Family - Revolving | Nonaccrual
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	3,726		4,629
Auto
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	409,228		398,206
Greater Than 90 Days and Still Accruing	168		166
Nonaccrual	179	500	500	565
Total Loans	411,073		401,324
Auto | Current
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	409,228		398,206
Auto | 30-59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	1,333		2,076
Total Loans	1,333		2,076
Auto | 60-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	165		376
Total Loans	165		376
Auto | 90+ Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	168		166
Auto | Nonaccrual
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	179		500
Consumer
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	193,934		245,551
Greater Than 90 Days and Still Accruing	156		394
Nonaccrual	104	$ 69	69	88
Total Loans	195,036		247,730
Consumer | Current
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	193,934		245,551
Consumer | 30-59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	545		1,166
Total Loans	545		1,166
Consumer | 60-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	297		550
Total Loans	297		550
Consumer | 90+ Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	156		394
Consumer | Nonaccrual
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	104		69
Other Commercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	599,901		489,959
Greater Than 90 Days and Still Accruing	0		0
Nonaccrual	0		0	$ 98
Total Loans	600,276		489,975
Other Commercial | 30-59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	375		16
Other Commercial | 60-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	$ 0		$ 0