Note 14 - Fair Value Measurements and Fair Value of Financial Instruments - Fair Value Hierarchy of Financial Instruments (Details) - USD ($) $ in Thousands	Jun. 30, 2026	Dec. 31, 2025
Equity Securities, FV-NI	$ 26,482	$ 32,754
Estimate of Fair Value Measurement [Member]
Cash and due from banks	163,976	146,320
Short-term investments	1,163,120	1,278,089
Loans held for investment, net	20,647,585	20,516,176
Equity Securities, FV-NI	1,539	1,539
Investment in Federal Home Loan Bank stock	17,250	17,250
Deposits	21,029,316	20,884,386
Long-term debt	83,157	79,818
Estimate of Fair Value Measurement [Member] \| Fair Value, Inputs, Level 1 [Member]
Cash and due from banks	163,976	146,320
Short-term investments	1,163,120	1,278,089
Loans held for investment, net	0	0
Equity Securities, FV-NI	0	0
Investment in Federal Home Loan Bank stock	0	0
Deposits	0	0
Long-term debt	0	0
Estimate of Fair Value Measurement [Member] \| Fair Value, Inputs, Level 2 [Member]
Cash and due from banks	0	0
Short-term investments	0	0
Loans held for investment, net	0	0
Equity Securities, FV-NI	0	0
Investment in Federal Home Loan Bank stock	17,250	17,250
Deposits	0	0
Long-term debt	83,157	79,818
Estimate of Fair Value Measurement [Member] \| Fair Value, Inputs, Level 3 [Member]
Cash and due from banks	0	0
Short-term investments	0	0
Loans held for investment, net	20,647,585	20,516,176
Equity Securities, FV-NI	1,539	1,539
Investment in Federal Home Loan Bank stock	0	0
Deposits	21,029,316	20,884,386
Long-term debt	$ 0	$ 0

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 portion of deposit liabilities held by the entity, including, but not limited to, foreign and domestic, interest and noninterest bearing, demand deposits, saving deposits, negotiable orders of withdrawal (NOW) and time deposits.

+ References

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

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- Definition

Fair value portion of investments in Federal Home Loan Bank (FHLBank) stock.

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Fair value portion of loan receivable, including, but not limited to, mortgage loans held for investment, finance receivables held for investment, policy loans on insurance contracts.

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- Definition

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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Amount of investments including trading securities, available-for-sale securities, held-to-maturity securities, and short-term investments classified as other and current.

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