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Investment Securities - Additional Information (Details) | 3 Months Ended |
--- | --- | ---
Mar. 31, 2024 USD ($) Position Security | Dec. 31, 2023 USD ($) Position Security
Schedule Of Available For Sale Securities [Line Items] |  |
Equity securities, at fair value | $ 4,298,000 | $ 4,074,000
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 | $ 820,000,000 | 831,000,000
Available-for-sale, 12 months or longer, Fair Value | 1,057,538,000 | 1,075,835,000
12 months or longer, unrealized losses | $ 203,245,000 | $ 192,616,000
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 | 625 | 36
Available-for-sale, 12 months or longer, Fair Value | $ 206,025,000 | $ 210,069,000
12 months or longer, unrealized losses | $ 27,220,000 | $ 26,215,000
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 | 255 | 237
Available-for-sale, 12 months or longer, Fair Value | $ 248,168,000 | $ 241,630,000
12 months or longer, unrealized losses | $ 52,540,000 | $ 49,038,000
Mortgage-backed Securities: GSE Residential |  |
Schedule Of Available For Sale Securities [Line Items] |  |
Number of securities in unrealized loss positions | Security | 263 | 263
Available-for-sale, 12 months or longer, Fair Value | $ 545,899,000 | $ 566,197,000
12 months or longer, unrealized losses | $ 119,639,000 | $ 113,007,000
Other Securities |  |
Schedule Of Available For Sale Securities [Line Items] |  |
Number of securities in unrealized loss positions | Security | 42 | 43
Available-for-sale, 12 months or longer, Fair Value | $ 57,446,000 | $ 57,939,000
12 months or longer, unrealized losses | $ 3,846,000 | $ 4,356,000

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