Loans Receivable and the Allowance for Credit Losses - Schedule of Composition of Loans by Lending Classification (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Financing Receivable, Impaired [Line Items]
Loans held for investment, net of unearned income	$ 4,126,947	$ 3,840,524
Allowance for credit losses	(51,500)	(49,200)	$ (48,700)	$ (55,500)
Total loans held for investment, net	4,075,447	3,791,324
Asset Pledged as Collateral without Right | FHLB borrowings
Financing Receivable, Impaired [Line Items]
Total loans held for investment, net	1,130,000	1,010,000
Agricultural
Financing Receivable, Impaired [Line Items]
Loans held for investment, net of unearned income	118,414	115,320
Allowance for credit losses	(613)	(923)	(667)	(1,346)
Commercial and Industrial
Financing Receivable, Impaired [Line Items]
Loans held for investment, net of unearned income	1,075,003	1,055,162
Allowance for credit losses	(21,743)	(22,855)	(17,294)	(15,689)
Commercial Real Estate
Financing Receivable, Impaired [Line Items]
Loans held for investment, net of unearned income	2,225,310	1,980,018
Allowance for credit losses	(23,759)	(20,123)	(26,120)	(32,640)
Commercial Real Estate | Construction & development
Financing Receivable, Impaired [Line Items]
Loans held for investment, net of unearned income	323,195	270,991
Commercial Real Estate | Farmland
Financing Receivable, Impaired [Line Items]
Loans held for investment, net of unearned income	184,955	183,913
Commercial Real Estate | Multifamily
Financing Receivable, Impaired [Line Items]
Loans held for investment, net of unearned income	383,178	252,129
Commercial Real Estate | Commercial real estate-other
Financing Receivable, Impaired [Line Items]
Loans held for investment, net of unearned income	1,333,982	1,272,985
Commercial Real Estate | One- to four- family first liens
Financing Receivable, Impaired [Line Items]
Loans held for investment, net of unearned income	459,798
Residential Real Estate
Financing Receivable, Impaired [Line Items]
Loans held for investment, net of unearned income	640,437	614,428
Allowance for credit losses	(4,762)	(4,678)	(4,010)	(4,882)
Residential Real Estate | One- to four- family first liens
Financing Receivable, Impaired [Line Items]
Loans held for investment, net of unearned income	459,798	451,210
Residential Real Estate | One- to four- family junior liens
Financing Receivable, Impaired [Line Items]
Loans held for investment, net of unearned income	180,639	163,218
Consumer
Financing Receivable, Impaired [Line Items]
Loans held for investment, net of unearned income	67,783	75,596
Allowance for credit losses	$ (623)	$ (621)	$ (609)	$ (943)