Fair Value of Financial Instruments - Estimated Fair Values and Carrying Values of Financial Instruments (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Financial assets:
Net loans held for investment	$ 9,185,360	$ 9,164,020
Interest receivable	44,973	45,684
Level 1
Financial liabilities:
Federal Home Loan Bank advances	0
Level 2
Financial liabilities:
Federal Home Loan Bank advances	125,000
Level 3
Financial liabilities:
Federal Home Loan Bank advances	0
Carrying amount
Financial assets:
Cash and cash equivalents	1,160,354	1,027,052
Investment securities	1,422,391	1,474,176
Net loans held for investment	9,185,360	9,164,020
Loans held for sale, at fair value	78,906	113,240
Interest receivable	44,973	45,684
Mortgage servicing rights	166,433	168,365
Derivatives	47,132	48,769
Financial liabilities:
Deposits, Without stated maturities	9,251,599	9,433,860
Deposits, With stated maturities	1,620,656	1,421,974
Securities sold under agreements to repurchase and federal funds purchased	116,220	86,945
Federal Home Loan Bank advances	125,000	175,000
Subordinated debt, net	127,535	126,101
Interest payable	16,897	8,648
Derivatives	54,544	63,229
Fair Value
Financial assets:
Cash and cash equivalents	1,160,354	1,027,052
Investment securities	1,422,391	1,474,176
Net loans held for investment	8,894,367	9,048,943
Loans held for sale, at fair value	78,906	113,240
Interest receivable	44,973	45,684
Mortgage servicing rights	166,433	168,365
Derivatives	47,132	48,769
Financial liabilities:
Deposits, Without stated maturities	9,251,599	9,433,860
Deposits, With stated maturities	1,611,764	1,422,544
Securities sold under agreements to repurchase and federal funds purchased	116,220	86,945
Federal Home Loan Bank advances	125,000	175,000
Subordinated debt, net	117,939	118,817
Interest payable	16,897	8,648
Derivatives	54,544	63,229
Fair Value | Level 1
Financial assets:
Cash and cash equivalents	1,160,354	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	234	126
Mortgage servicing rights	0	0
Derivatives	0	0
Financial liabilities:
Deposits, Without stated maturities	9,251,599	9,433,860
Deposits, With stated maturities	0	0
Securities sold under agreements to repurchase and federal funds purchased	116,220	86,945
Federal Home Loan Bank advances		0
Subordinated debt, net	0	0
Interest payable	3,503	2,571
Derivatives	0	0
Fair Value | Level 2
Financial assets:
Cash and cash equivalents	0	0
Investment securities	1,422,391	1,474,176
Net loans held for investment	0	0
Loans held for sale, at fair value	69,639	82,750
Interest receivable	6,682	6,961
Mortgage servicing rights	0	0
Derivatives	47,132	48,769
Financial liabilities:
Deposits, Without stated maturities	0	0
Deposits, With stated maturities	1,611,764	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	11,894	4,559
Derivatives	54,544	63,229
Fair Value | Level 3
Financial assets:
Cash and cash equivalents	0	0
Investment securities	0	0
Net loans held for investment	8,894,367	9,048,943
Loans held for sale, at fair value	9,267	30,490
Interest receivable	38,057	38,597
Mortgage servicing rights	166,433	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	117,939	118,817
Interest payable	1,500	1,518
Derivatives	$ 0	$ 0