LOANS AND ALLOWANCE FOR CREDIT LOSSES - Allowance for Loan Losses (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Allowance for Loan and Lease Losses [Roll Forward]
Balance at beginning of period	$ 199,422	$ 38,189	$ 28,819
Initial allowance for PCD assets	9,432
Provision for credit losses	(35,081)	125,488	19,758
Loans charged off	(21,616)	(54,464)	(19,861)
Recoveries of loans previously charged off	15,425	11,548	9,473
Balance at end of period	167,582	199,422	38,189
Loans individually evaluated for impairment			7,162
Loans collectively evaluated for impairment			31,027
Allowance for credit losses	167,582	199,422	38,189
Individually evaluated for impairment			82,475
Collectively evaluated for impairment			12,609,278
Acquired with deteriorated credit quality			126,723
Loans, net of unearned income	15,874,258	14,480,925	12,818,476
Financing receivable, nonaccrual	85,266	76,457
Accounting Standards Update 2016-13
Allowance for Loan and Lease Losses [Roll Forward]
Balance at beginning of period	78,661
Balance at end of period		78,661
Allowance for credit losses		78,661
Commercial, financial and agricultural
Allowance for Loan and Lease Losses [Roll Forward]
Balance at beginning of period	7,359	4,567	2,352
Initial allowance for PCD assets	9,432
Provision for credit losses	12,071	8,963	3,837
Loans charged off	(7,760)	(10,647)	(3,460)
Recoveries of loans previously charged off	5,727	1,889	1,838
Balance at end of period	26,829	7,359	4,567
Loans individually evaluated for impairment			1,543
Loans collectively evaluated for impairment			3,024
Allowance for credit losses	26,829	7,359	4,567
Individually evaluated for impairment			8,032
Collectively evaluated for impairment			789,252
Acquired with deteriorated credit quality			4,887
Loans, net of unearned income	1,875,993	1,627,477	802,171
Financing receivable, nonaccrual	14,214	9,836
Commercial, financial and agricultural | Accounting Standards Update 2016-13
Allowance for Loan and Lease Losses [Roll Forward]
Balance at beginning of period	2,587
Balance at end of period		2,587
Allowance for credit losses		2,587
Consumer installment
Allowance for Loan and Lease Losses [Roll Forward]
Balance at beginning of period	4,076	3,784	3,795
Initial allowance for PCD assets	0
Provision for credit losses	7,330	(3,831)	4,268
Loans charged off	(6,248)	(5,642)	(5,899)
Recoveries of loans previously charged off	939	1,753	1,620
Balance at end of period	6,097	4,076	3,784
Loans individually evaluated for impairment			0
Loans collectively evaluated for impairment			3,784
Allowance for credit losses	6,097	4,076	3,784
Individually evaluated for impairment			0
Collectively evaluated for impairment			498,363
Acquired with deteriorated credit quality			214
Loans, net of unearned income	191,298	306,995	498,577
Financing receivable, nonaccrual	476	709
Consumer installment | Accounting Standards Update 2016-13
Allowance for Loan and Lease Losses [Roll Forward]
Balance at beginning of period	8,012
Balance at end of period		8,012
Allowance for credit losses		8,012
Indirect automobile
Allowance for Loan and Lease Losses [Roll Forward]
Balance at beginning of period	1,929	0	0
Initial allowance for PCD assets	0
Provision for credit losses	(1,944)	(235)	1,459
Loans charged off	(1,188)	(3,602)	(1,904)
Recoveries of loans previously charged off	1,679	1,657	445
Balance at end of period	476	1,929	0
Loans individually evaluated for impairment			0
Loans collectively evaluated for impairment			0
Allowance for credit losses	476	1,929	0
Individually evaluated for impairment			0
Collectively evaluated for impairment			1,056,811
Acquired with deteriorated credit quality			5,013
Loans, net of unearned income	265,779	580,083	1,061,824
Financing receivable, nonaccrual	947	2,831
Indirect automobile | Accounting Standards Update 2016-13
Allowance for Loan and Lease Losses [Roll Forward]
Balance at beginning of period	4,109
Balance at end of period		4,109
Allowance for credit losses		4,109
Mortgage warehouse
Allowance for Loan and Lease Losses [Roll Forward]
Balance at beginning of period	3,666	640	640
Initial allowance for PCD assets	0
Provision for credit losses	(435)	2,563	0
Loans charged off	0	0	0
Recoveries of loans previously charged off	0	0	0
Balance at end of period	3,231	3,666	640
Loans individually evaluated for impairment			0
Loans collectively evaluated for impairment			640
Allowance for credit losses	3,231	3,666	640
Individually evaluated for impairment			0
Collectively evaluated for impairment			526,369
Acquired with deteriorated credit quality			0
Loans, net of unearned income	787,837	916,353	526,369
Municipal
Allowance for Loan and Lease Losses [Roll Forward]
Balance at beginning of period	791	484	509
Initial allowance for PCD assets	0
Provision for credit losses	(390)	399	(25)
Loans charged off	0	0	0
Recoveries of loans previously charged off	0	0	0
Balance at end of period	401	791	484
Loans individually evaluated for impairment			0
Loans collectively evaluated for impairment			484
Allowance for credit losses	401	791	484
Individually evaluated for impairment			0
Collectively evaluated for impairment			564,304
Acquired with deteriorated credit quality			0
Loans, net of unearned income	572,701	659,403	564,304
Municipal | Accounting Standards Update 2016-13
Allowance for Loan and Lease Losses [Roll Forward]
Balance at beginning of period	(92)
Balance at end of period		(92)
Allowance for credit losses		(92)
Premium finance
Allowance for Loan and Lease Losses [Roll Forward]
Balance at beginning of period	3,879	2,550	1,426
Initial allowance for PCD assets	0
Provision for credit losses	(2,352)	(198)	2,721
Loans charged off	(3,668)	(6,133)	(4,351)
Recoveries of loans previously charged off	4,870	3,189	2,754
Balance at end of period	2,729	3,879	2,550
Loans individually evaluated for impairment			758
Loans collectively evaluated for impairment			1,792
Allowance for credit losses	2,729	3,879	2,550
Individually evaluated for impairment			6,768
Collectively evaluated for impairment			647,901
Acquired with deteriorated credit quality			0
Loans, net of unearned income	798,409	687,841	654,669
Premium finance | Accounting Standards Update 2016-13
Allowance for Loan and Lease Losses [Roll Forward]
Balance at beginning of period	4,471
Balance at end of period		4,471
Allowance for credit losses		4,471
Real estate – construction and development
Allowance for Loan and Lease Losses [Roll Forward]
Balance at beginning of period	45,304	5,995	4,210
Initial allowance for PCD assets	0
Provision for credit losses	(23,532)	26,327	454
Loans charged off	(233)	(83)	(414)
Recoveries of loans previously charged off	506	817	1,745
Balance at end of period	22,045	45,304	5,995
Loans individually evaluated for impairment			204
Loans collectively evaluated for impairment			5,791
Allowance for credit losses	22,045	45,304	5,995
Individually evaluated for impairment			1,605
Collectively evaluated for impairment			1,532,786
Acquired with deteriorated credit quality			14,671
Loans, net of unearned income	1,452,339	1,606,710	1,549,062
Financing receivable, nonaccrual	492	5,407
Real estate – construction and development | Accounting Standards Update 2016-13
Allowance for Loan and Lease Losses [Roll Forward]
Balance at beginning of period	12,248
Balance at end of period		12,248
Allowance for credit losses		12,248
Real estate – commercial and farmland
Allowance for Loan and Lease Losses [Roll Forward]
Balance at beginning of period	88,894	9,666	9,659
Initial allowance for PCD assets	0
Provision for credit losses	(9,784)	78,210	3,017
Loans charged off	(1,852)	(27,504)	(3,342)
Recoveries of loans previously charged off	573	1,449	332
Balance at end of period	77,831	88,894	9,666
Loans individually evaluated for impairment			953
Loans collectively evaluated for impairment			8,713
Allowance for credit losses	77,831	88,894	9,666
Individually evaluated for impairment			19,759
Collectively evaluated for impairment			4,256,397
Acquired with deteriorated credit quality			76,883
Loans, net of unearned income	6,834,917	5,300,006	4,353,039
Financing receivable, nonaccrual	15,365	18,517
Real estate – commercial and farmland | Accounting Standards Update 2016-13
Allowance for Loan and Lease Losses [Roll Forward]
Balance at beginning of period	27,073
Balance at end of period		27,073
Allowance for credit losses		27,073
Real estate – residential
Allowance for Loan and Lease Losses [Roll Forward]
Balance at beginning of period	43,524	10,503	6,228
Initial allowance for PCD assets	0
Provision for credit losses	(16,045)	13,290	4,027
Loans charged off	(667)	(853)	(491)
Recoveries of loans previously charged off	1,131	794	739
Balance at end of period	27,943	43,524	10,503
Loans individually evaluated for impairment			3,704
Loans collectively evaluated for impairment			6,799
Allowance for credit losses	27,943	43,524	10,503
Individually evaluated for impairment			46,311
Collectively evaluated for impairment			2,737,095
Acquired with deteriorated credit quality			25,055
Loans, net of unearned income	3,094,985	2,796,057	2,808,461
Financing receivable, nonaccrual	53,772	39,157
Real estate – residential | Accounting Standards Update 2016-13
Allowance for Loan and Lease Losses [Roll Forward]
Balance at beginning of period	19,790
Balance at end of period		19,790
Allowance for credit losses		19,790
Mortgage Warehouse, Portfolio Segment
Allowance for Loan and Lease Losses [Roll Forward]
Loans, net of unearned income		916,353
Mortgage Warehouse, Portfolio Segment | Accounting Standards Update 2016-13
Allowance for Loan and Lease Losses [Roll Forward]
Balance at beginning of period	$ 463
Balance at end of period		463
Allowance for credit losses		$ 463
Substandard | Minimum
Allowance for Loan and Lease Losses [Roll Forward]
Financing receivable, nonaccrual			100
Troubled debt restructuring loans			$ 100