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Investment Securities - Additional Information (Details) $ in Thousands | 9 Months Ended |
--- | --- | ---
Sep. 30, 2024 USD ($) Position Security | Dec. 31, 2023 USD ($) Position Security
Schedule Of Available For Sale Securities [Line Items] |  |
Equity securities, at fair value | $ 4,424 | $ 4,074
Tax rate used to calculate tax-equivalent yields (in hundredths) | 21.00% |
Percentage investment book value exceeds stockholders' equity (in hundredths) | 10.00% |
Debt securities, available-for-sale, restricted | $ 834,100 | 831,000
Available-for-sale, 12 months or longer, Fair Value | 1,050,204 | 1,075,835
12 months or longer, unrealized losses | $ 160,096 | $ 192,616
U.S. Treasury Securities and Obligations of U.S. Government Corporations and Agencies |  |
Schedule Of Available For Sale Securities [Line Items] |  |
Number of securities in unrealized loss positions | Security | 28 | 36
Available-for-sale, 12 months or longer, Fair Value | $ 193,524 | $ 210,069
12 months or longer, unrealized losses | $ 18,091 | $ 26,215
Held-to-maturity, securities in unrealized loss positions, qualitative disclosure, number of positions | Position | 0 | 0
Obligations of States and Political Subdivisions |  |
Schedule Of Available For Sale Securities [Line Items] |  |
Number of securities in unrealized loss positions | Security | 247 | 237
Available-for-sale, 12 months or longer, Fair Value | $ 251,107 | $ 241,630
12 months or longer, unrealized losses | $ 45,729 | $ 49,038
Mortgage-backed Securities: GSE Residential |  |
Schedule Of Available For Sale Securities [Line Items] |  |
Number of securities in unrealized loss positions | Security | 242 | 263
Available-for-sale, 12 months or longer, Fair Value | $ 547,233 | $ 566,197
12 months or longer, unrealized losses | $ 93,269 | $ 113,007
Other Securities |  |
Schedule Of Available For Sale Securities [Line Items] |  |
Number of securities in unrealized loss positions | Security | 40 | 43
Available-for-sale, 12 months or longer, Fair Value | $ 58,340 | $ 57,939
12 months or longer, unrealized losses | $ 3,007 | $ 4,356

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