Allowance for Credit Losses - Changes in the Allowance for Credit Loss (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Allowance for credit losses on loans:
Beginning balance	$ 164,171	$ 176,144
Charge-offs	(14,185)	(18,874)
Recoveries	6,856	8,601
Net charge-offs	(7,329)	(10,273)
Provision (recoveries) of credit losses on loans	23,788	(1,700)	$ 85,350
Ending balance	192,090	164,171	176,144
Individually evaluated	6,442	12,463
Collectively evaluated	185,648	151,708
Loans:
Individually evaluated	29,450	33,449
Collectively evaluated	11,548,854	9,987,465
Loans held for investment, net of unearned income	11,578,304	10,020,914
Nonaccruing loans with no allowance for credit losses	$ 10,899	8,018
Supportable period	2 years
Commercial
Allowance for credit losses on loans:
Beginning balance	$ 33,922	39,031
Charge-offs	(5,120)	(7,087)
Recoveries	2,471	1,470
Net charge-offs	(2,649)	(5,617)
Provision (recoveries) of credit losses on loans	1,522	508
Ending balance	44,255	33,922	39,031
Individually evaluated	4,397	9,239
Collectively evaluated	39,858	24,683
Loans:
Individually evaluated	8,536	12,776
Collectively evaluated	1,665,347	1,410,494
Loans held for investment, net of unearned income	1,673,883	1,423,270
Nonaccruing loans with no allowance for credit losses	464	397
Real Estate - Construction
Allowance for credit losses on loans:
Beginning balance	16,419	16,047
Charge-offs	0	(52)
Recoveries	0	13
Net charge-offs	0	(39)
Provision (recoveries) of credit losses on loans	2,695	411
Ending balance	19,114	16,419	16,047
Individually evaluated	0	0
Collectively evaluated	19,114	16,419
Loans:
Individually evaluated	489	0
Collectively evaluated	1,329,848	1,104,896
Loans held for investment, net of unearned income	1,330,337	1,104,896
Nonaccruing loans with no allowance for credit losses	0	0
Real Estate - 1-4 Family Mortgage
Allowance for credit losses on loans:
Beginning balance	32,356	32,165
Charge-offs	(757)	(1,164)
Recoveries	821	1,498
Net charge-offs	64	334
Provision (recoveries) of credit losses on loans	12,307	(143)
Ending balance	44,727	32,356	32,165
Individually evaluated	46	216
Collectively evaluated	44,681	32,140
Loans:
Individually evaluated	9,202	5,360
Collectively evaluated	3,207,061	2,718,886
Loans held for investment, net of unearned income	3,216,263	2,724,246
Nonaccruing loans with no allowance for credit losses	7,278	2,329
Real estate – commercial mortgage:
Allowance for credit losses on loans:
Beginning balance	68,940	76,127
Charge-offs	(5,134)	(5,184)
Recoveries	418	541
Net charge-offs	(4,716)	(4,643)
Provision (recoveries) of credit losses on loans	7,574	(2,544)
Ending balance	71,798	68,940	76,127
Individually evaluated	1,729	2,401
Collectively evaluated	70,069	66,539
Loans:
Individually evaluated	10,953	14,623
Collectively evaluated	5,107,110	4,534,414
Loans held for investment, net of unearned income	5,118,063	4,549,037
Nonaccruing loans with no allowance for credit losses	3,157	5,270
Lease financing
Allowance for credit losses on loans:
Beginning balance	1,486	1,624
Charge-offs	(7)	(13)
Recoveries	146	49
Net charge-offs	139	36
Provision (recoveries) of credit losses on loans	838	(174)
Ending balance	2,463	1,486	1,624
Individually evaluated	0	0
Collectively evaluated	2,463	1,486
Loans:
Individually evaluated	0	0
Collectively evaluated	115,013	76,125
Loans held for investment, net of unearned income	115,013	76,125
Nonaccruing loans with no allowance for credit losses	0	0
Installment loans to individuals
Allowance for credit losses on loans:
Beginning balance	11,048	11,150
Charge-offs	(3,167)	(5,374)
Recoveries	3,000	5,030
Net charge-offs	(167)	(344)
Provision (recoveries) of credit losses on loans	(1,148)	242
Ending balance	9,733	11,048	$ 11,150
Individually evaluated	270	607
Collectively evaluated	9,463	10,441
Loans:
Individually evaluated	270	690
Collectively evaluated	124,475	142,650
Loans held for investment, net of unearned income	124,745	143,340
Nonaccruing loans with no allowance for credit losses	0	22
Impact of the adoption of ASC 326
Allowance for credit losses on loans:
Beginning balance	11,460
Ending balance		11,460
Impact of the adoption of ASC 326 \| Commercial
Allowance for credit losses on loans:
Beginning balance	11,460
Ending balance		11,460
Impact of the adoption of ASC 326 \| Real Estate - Construction
Allowance for credit losses on loans:
Beginning balance	0
Ending balance		0
Impact of the adoption of ASC 326 \| Real Estate - 1-4 Family Mortgage
Allowance for credit losses on loans:
Beginning balance	0
Ending balance		0
Impact of the adoption of ASC 326 \| Real estate – commercial mortgage:
Allowance for credit losses on loans:
Beginning balance	0
Ending balance		0
Impact of the adoption of ASC 326 \| Lease financing
Allowance for credit losses on loans:
Beginning balance	0
Ending balance		0
Impact of the adoption of ASC 326 \| Installment loans to individuals
Allowance for credit losses on loans:
Beginning balance	$ 0
Ending balance		$ 0

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