LOANS AND ALLOWANCE FOR LOAN LOSSES (Summary of Aging of the Loan Portfolio by Class) (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Jan. 01, 2020	Dec. 31, 2019
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	$ 12,649,743		$ 12,419,378
Greater Than 90 Days and Still Accruing	12,876		13,396
Nonaccrual	44,022	$ 45,204	28,232
Total Loans	12,768,841		12,610,936
30-59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	48,868		50,453
60-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	13,332		12,796
Purchased Impaired
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current			70,267
Total Loans	84,700		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	1,311,599		1,231,043
Greater Than 90 Days and Still Accruing	317		189
Nonaccrual	3,234	4,060	3,703
Total Loans	1,318,252		1,250,924
Construction and Land Development | 30-59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	2,786		4,563
Construction and Land Development | 60-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	316		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	2,026,741		2,001,074
Greater Than 90 Days and Still Accruing	1,690		1,062
Nonaccrual	11,250	13,889	6,003
Total Loans	2,051,904		2,041,243
Commercial Real Estate - Owner Occupied | 30-59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	10,779		3,482
Commercial Real Estate - Owner Occupied | 60-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	1,444		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	3,319,481		3,269,244
Greater Than 90 Days and Still Accruing	2,037		1,451
Nonaccrual	1,642	1,368	381
Total Loans	3,328,012		3,286,098
Commercial Real Estate - Non-Owner Occupied | 30-59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	2,087		457
Commercial Real Estate - Non-Owner Occupied | 60-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	2,765		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	676,343		632,952
Greater Than 90 Days and Still Accruing	377		474
Nonaccrual	53	0	0
Total Loans	679,390		633,743
Multifamily Real Estate | 30-59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	623		223
Multifamily Real Estate | 60-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	1,994		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	2,167,873		2,099,974
Greater Than 90 Days and Still Accruing	517		449
Nonaccrual	3,431	3,037	1,735
Total Loans	2,177,932		2,114,033
Commercial and Industrial | 30-59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	4,893		8,698
Commercial and Industrial | 60-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	1,218		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	708,772		703,471
Greater Than 90 Days and Still Accruing	777		674
Nonaccrual	7,040	6,492	4,301
Total Loans	721,800		724,337
Residential 1-4 Family - Commercial | 30-59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	4,145		1,479
Residential 1-4 Family - Commercial | 60-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	1,066		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	820,818		842,667
Greater Than 90 Days and Still Accruing	4,407		4,515
Nonaccrual	13,088	13,117	9,292
Total Loans	854,550		890,503
Residential 1-4 Family - Consumer | 30-59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	15,667		16,244
Total Loans	15,667
Residential 1-4 Family - Consumer | 60-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	570		3,072
Total Loans	570
Residential 1-4 Family - Consumer | 90+ Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	4,407
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	640,989		637,966
Greater Than 90 Days and Still Accruing	2,005		3,357
Nonaccrual	3,547	2,490	2,080
Total Loans	652,135		659,504
Residential 1-4 Family - Revolving | 30-59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	4,308		10,190
Total Loans	4,308
Residential 1-4 Family - Revolving | 60-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	1,286		1,784
Total Loans	1,286
Residential 1-4 Family - Revolving | 90+ Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	2,005
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	355,084		346,819
Greater Than 90 Days and Still Accruing	127		272
Nonaccrual	550	565	563
Total Loans	358,039		350,419
Auto | 30-59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	1,967		2,525
Total Loans	1,967
Auto | 60-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	311		236
Total Loans	311
Auto | 90+ Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	127
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	348,953		367,794
Greater Than 90 Days and Still Accruing	622		953
Nonaccrual	91	88	77
Total Loans	352,572		372,853
Consumer | 30-59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	1,612		2,128
Total Loans	1,612
Consumer | 60-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	1,294		1,233
Total Loans	1,294
Consumer | 90+ Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	622
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	273,090		286,374
Greater Than 90 Days and Still Accruing	0		0
Nonaccrual	96	$ 98	97
Total Loans	274,255		287,279
Other Commercial | 30-59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	1		464
Other Commercial | 60-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	$ 1,068		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