Fair Value of Financial Instruments - Estimated Fair Values and Carrying Values of Financial Instruments (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Financial assets:
Net loans held for investment	$ 9,227,187	$ 9,164,020
Interest receivable	44,737	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	1,319,951	1,027,052
Investment securities	1,474,064	1,474,176
Net loans held for investment	9,227,187	9,164,020
Loans held for sale, at fair value	61,987	113,240
Interest receivable	44,737	45,684
Mortgage servicing rights	164,879	168,365
Derivatives	39,799	48,769
Financial liabilities:
Deposits, Without stated maturities	9,686,045	9,433,860
Deposits, With stated maturities	1,496,870	1,421,974
Securities sold under agreements to repurchase and federal funds purchased	38,130	86,945
Federal Home Loan Bank advances	125,000	175,000
Subordinated debt, net	127,076	126,101
Interest payable	11,834	8,648
Derivatives	48,461	63,229
Fair Value
Financial assets:
Cash and cash equivalents	1,319,951	1,027,052
Investment securities	1,474,064	1,474,176
Net loans held for investment	9,090,899	9,048,943
Loans held for sale, at fair value	61,987	113,240
Interest receivable	44,737	45,684
Mortgage servicing rights	164,879	168,365
Derivatives	39,799	48,769
Financial liabilities:
Deposits, Without stated maturities	9,686,045	9,433,860
Deposits, With stated maturities	1,485,091	1,422,544
Securities sold under agreements to repurchase and federal funds purchased	38,130	86,945
Federal Home Loan Bank advances	125,000	175,000
Subordinated debt, net	120,584	118,817
Interest payable	11,834	8,648
Derivatives	48,461	63,229
Fair Value \| Level 1
Financial assets:
Cash and cash equivalents	1,319,951	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	1,027	126
Mortgage servicing rights	0	0
Derivatives	0	0
Financial liabilities:
Deposits, Without stated maturities	9,686,045	9,433,860
Deposits, With stated maturities	0	0
Securities sold under agreements to repurchase and federal funds purchased	38,130	86,945
Federal Home Loan Bank advances		0
Subordinated debt, net	0	0
Interest payable	3,731	2,571
Derivatives	0	0
Fair Value \| Level 2
Financial assets:
Cash and cash equivalents	0	0
Investment securities	1,474,064	1,474,176
Net loans held for investment	0	0
Loans held for sale, at fair value	52,477	82,750
Interest receivable	6,705	6,961
Mortgage servicing rights	0	0
Derivatives	39,799	48,769
Financial liabilities:
Deposits, Without stated maturities	0	0
Deposits, With stated maturities	1,485,091	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	7,704	4,559
Derivatives	48,461	63,229
Fair Value \| Level 3
Financial assets:
Cash and cash equivalents	0	0
Investment securities	0	0
Net loans held for investment	9,090,899	9,048,943
Loans held for sale, at fair value	9,510	30,490
Interest receivable	37,005	38,597
Mortgage servicing rights	164,879	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	120,584	118,817
Interest payable	399	1,518
Derivatives	$ 0	$ 0

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Deposits without stated maturities fair value disclosure.

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Fair value portion of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

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Fair value, after the effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets not subject to a master netting arrangement and not elected to be offset.

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Amortized cost excluding accrued interest, after allowance for credit loss, of financing receivable. Excludes net investment in lease.

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Amount of interest payable on debt, including, but not limited to, trade payables.

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Carrying amount as of the balance sheet date of interest earned but not received. Also called accrued interest or accrued interest receivable.

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Fair value portion of loans held-for-sale including, but not limited to, mortgage loans and finance receivables.

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The fair value amount of long-term debt whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission.

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Fair value portion of securities that an entity sells and agrees to repurchase at a specified date for a specified price.

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Fair value of an asset representing net future revenue from contractually specified servicing fees, late charges, and other ancillary revenues, in excess of future costs related to servicing arrangements.

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Amount of investment in debt security measured at fair value with change in fair value recognized in net income (trading) and investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI).

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