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Note 9 - Fair Value Measurements - Assets Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Thousands | Mar. 31, 2025 | Dec. 31, 2024
--- | --- | ---
Debt securities available for sale | $ 3,236,049 | $ 3,395,810
Agency Residential MBS [Member] |  |
Debt securities available for sale | 204,342 | 211,060
Agency Commercial MBS [Member] |  |
Debt securities available for sale | 46,502 | 6,966
US Government Agencies Debt Securities [Member] |  |
Debt securities available for sale | 299,722 | 292,117
US Treasury Securities [Member] |  |
Debt securities available for sale |  | 4,955
US States and Political Subdivisions Debt Securities [Member] |  |
Debt securities available for sale | 60,581 | 62,186
Corporate Debt Securities [Member] |  |
Debt securities available for sale | 1,802,791 | 1,835,937
Fair Value, Recurring [Member] |  |
Debt securities available for sale | 3,236,049 | 3,395,810
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] |  |
Debt securities available for sale | 0 | 4,955
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] |  |
Debt securities available for sale | 3,236,049 | 3,390,855
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] |  |
Debt securities available for sale | 0 | 0
Fair Value, Recurring [Member] | Agency Residential MBS [Member] |  |
Debt securities available for sale | 204,342 | 211,060
Fair Value, Recurring [Member] | Agency Residential MBS [Member] | Fair Value, Inputs, Level 1 [Member] |  |
Debt securities available for sale | 0 | 0
Fair Value, Recurring [Member] | Agency Residential MBS [Member] | Fair Value, Inputs, Level 2 [Member] |  |
Debt securities available for sale | 204,342 | 211,060
Fair Value, Recurring [Member] | Agency Residential MBS [Member] | Fair Value, Inputs, Level 3 [Member] |  |
Debt securities available for sale | 0 | 0
Fair Value, Recurring [Member] | Agency Commercial MBS [Member] |  |
Debt securities available for sale | 46,502 | 6,966
Fair Value, Recurring [Member] | Agency Commercial MBS [Member] | Fair Value, Inputs, Level 1 [Member] |  |
Debt securities available for sale | 0 | 0
Fair Value, Recurring [Member] | Agency Commercial MBS [Member] | Fair Value, Inputs, Level 2 [Member] |  |
Debt securities available for sale | 46,502 | 6,966
Fair Value, Recurring [Member] | Agency Commercial MBS [Member] | Fair Value, Inputs, Level 3 [Member] |  |
Debt securities available for sale | 0 | 0
Fair Value, Recurring [Member] | US Government Agencies Debt Securities [Member] |  |
Debt securities available for sale | 299,722 | 292,117
Fair Value, Recurring [Member] | US Government Agencies Debt Securities [Member] | Fair Value, Inputs, Level 1 [Member] |  |
Debt securities available for sale | 0 | 0
Fair Value, Recurring [Member] | US Government Agencies Debt Securities [Member] | Fair Value, Inputs, Level 2 [Member] |  |
Debt securities available for sale | 299,722 | 292,117
Fair Value, Recurring [Member] | US Government Agencies Debt Securities [Member] | Fair Value, Inputs, Level 3 [Member] |  |
Debt securities available for sale | 0 | 0
Fair Value, Recurring [Member] | US Treasury Securities [Member] |  |
Debt securities available for sale |  | 4,955
Fair Value, Recurring [Member] | US Treasury Securities [Member] | Fair Value, Inputs, Level 1 [Member] |  |
Debt securities available for sale |  | 4,955
Fair Value, Recurring [Member] | US Treasury Securities [Member] | Fair Value, Inputs, Level 2 [Member] |  |
Debt securities available for sale |  | 0
Fair Value, Recurring [Member] | US Treasury Securities [Member] | Fair Value, Inputs, Level 3 [Member] |  |
Debt securities available for sale |  | 0
Fair Value, Recurring [Member] | US States and Political Subdivisions Debt Securities [Member] |  |
Debt securities available for sale | 60,581 | 62,186
Fair Value, Recurring [Member] | US States and Political Subdivisions Debt Securities [Member] | Fair Value, Inputs, Level 1 [Member] |  |
Debt securities available for sale | 0 | 0
Fair Value, Recurring [Member] | US States and Political Subdivisions Debt Securities [Member] | Fair Value, Inputs, Level 2 [Member] |  |
Debt securities available for sale | 60,581 | 62,186
Fair Value, Recurring [Member] | US States and Political Subdivisions Debt Securities [Member] | Fair Value, Inputs, Level 3 [Member] |  |
Debt securities available for sale | 0 | 0
Fair Value, Recurring [Member] | Corporate Debt Securities [Member] |  |
Debt securities available for sale | 1,802,791 | 1,835,937
Fair Value, Recurring [Member] | Corporate Debt Securities [Member] | Fair Value, Inputs, Level 1 [Member] |  |
Debt securities available for sale | 0 | 0
Fair Value, Recurring [Member] | Corporate Debt Securities [Member] | Fair Value, Inputs, Level 2 [Member] |  |
Debt securities available for sale | 1,802,791 | 1,835,937
Fair Value, Recurring [Member] | Corporate Debt Securities [Member] | Fair Value, Inputs, Level 3 [Member] |  |
Debt securities available for sale | 0 | 0
Fair Value, Recurring [Member] | Collateralized Loan Obligations [Member] |  |
Debt securities available for sale | 822,111 | 982,589
Fair Value, Recurring [Member] | Collateralized Loan Obligations [Member] | Fair Value, Inputs, Level 1 [Member] |  |
Debt securities available for sale | 0 | 0
Fair Value, Recurring [Member] | Collateralized Loan Obligations [Member] | Fair Value, Inputs, Level 2 [Member] |  |
Debt securities available for sale | 822,111 | 982,589
Fair Value, Recurring [Member] | Collateralized Loan Obligations [Member] | Fair Value, Inputs, Level 3 [Member] |  |
Debt securities available for sale | $ 0 | $ 0

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