Fair Value of Financial Instruments - Schedule of Estimated Fair Values and Carrying Values of Financial Instruments (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Financial assets:
Net loans held for investment	$ 9,141,091	$ 9,164,020
Interest receivable	49,205	45,684
Level 1
Financial liabilities:
Federal Home Loan Bank advances	0
Level 2
Financial liabilities:
Federal Home Loan Bank advances	0
Level 3
Financial liabilities:
Federal Home Loan Bank advances	0
Carrying amount
Financial assets:
Cash and cash equivalents	848,318	1,027,052
Investment securities	1,351,153	1,474,176
Net loans held for investment	9,141,091	9,164,020
Loans held for sale, at fair value	81,784	113,240
Interest receivable	49,205	45,684
Mortgage servicing rights	172,710	168,365
Derivatives	51,703	48,769
Financial liabilities:
Deposits, Without stated maturities	9,032,433	9,433,860
Deposits, With stated maturities	1,606,635	1,421,974
Securities sold under agreements to repurchase and federal funds purchased	74,705	86,945
Federal Home Loan Bank advances	0	175,000
Subordinated debt, net	128,560	126,101
Interest payable	20,581	8,648
Derivatives	59,025	63,229
Fair Value
Financial assets:
Cash and cash equivalents	848,318	1,027,052
Investment securities	1,351,153	1,474,176
Net loans held for investment	8,859,673	9,048,943
Loans held for sale, at fair value	81,784	113,240
Interest receivable	49,205	45,684
Mortgage servicing rights	172,710	168,365
Derivatives	51,703	48,769
Financial liabilities:
Deposits, Without stated maturities	9,032,433	9,433,860
Deposits, With stated maturities	1,610,908	1,422,544
Securities sold under agreements to repurchase and federal funds purchased	74,705	86,945
Federal Home Loan Bank advances	0	175,000
Subordinated debt, net	119,605	118,817
Interest payable	20,581	8,648
Derivatives	59,025	63,229
Fair Value | Level 1
Financial assets:
Cash and cash equivalents	848,318	1,027,052
Investment securities	0	0
Net loans held for investment	0	0
Loans held for sale, at fair value	0	0
Interest receivable	851	126
Mortgage servicing rights	0	0
Derivatives	0	0
Financial liabilities:
Deposits, Without stated maturities	9,032,433	9,433,860
Deposits, With stated maturities	0	0
Securities sold under agreements to repurchase and federal funds purchased	74,705	86,945
Federal Home Loan Bank advances		0
Subordinated debt, net	0	0
Interest payable	3,906	2,571
Derivatives	0	0
Fair Value | Level 2
Financial assets:
Cash and cash equivalents	0	0
Investment securities	1,351,153	1,474,176
Net loans held for investment	0	0
Loans held for sale, at fair value	72,524	82,750
Interest receivable	6,428	6,961
Mortgage servicing rights	0	0
Derivatives	51,703	48,769
Financial liabilities:
Deposits, Without stated maturities	0	0
Deposits, With stated maturities	1,610,908	1,422,544
Securities sold under agreements to repurchase and federal funds purchased	0	0
Federal Home Loan Bank advances		175,000
Subordinated debt, net	0	0
Interest payable	16,300	4,559
Derivatives	59,025	63,229
Fair Value | Level 3
Financial assets:
Cash and cash equivalents	0	0
Investment securities	0	0
Net loans held for investment	8,859,673	9,048,943
Loans held for sale, at fair value	9,260	30,490
Interest receivable	41,926	38,597
Mortgage servicing rights	172,710	168,365
Derivatives	0	0
Financial liabilities:
Deposits, Without stated maturities	0	0
Deposits, With stated maturities	0	0
Securities sold under agreements to repurchase and federal funds purchased	0	0
Federal Home Loan Bank advances		0
Subordinated debt, net	119,605	118,817
Interest payable	375	1,518
Derivatives	$ 0	$ 0