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Investment Securities - Additional Information (Details) | 6 Months Ended |
--- | --- | ---
Jun. 30, 2024 USD ($) Position Security | Dec. 31, 2023 USD ($) Position Security
Schedule Of Available For Sale Securities [Line Items] |  |
Equity securities, at fair value | $ 4,258,000 | $ 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 | $ 728,000,000 | 831,000,000
Available-for-sale, 12 months or longer, Fair Value | 1,036,465,000 | 1,075,835,000
12 months or longer, unrealized losses | $ 199,931,000 | $ 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 | 32 | 36
Available-for-sale, 12 months or longer, Fair Value | $ 196,288,000 | $ 210,069,000
12 months or longer, unrealized losses | $ 25,248,000 | $ 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 | 0 | 237
Available-for-sale, 12 months or longer, Fair Value | $ 247,125,000 | $ 241,630,000
12 months or longer, unrealized losses | $ 56,082,000 | $ 49,038,000
Mortgage-backed Securities: GSE Residential |  |
Schedule Of Available For Sale Securities [Line Items] |  |
Number of securities in unrealized loss positions | Security | 250 | 263
Available-for-sale, 12 months or longer, Fair Value | $ 535,856,000 | $ 566,197,000
12 months or longer, unrealized losses | $ 114,474,000 | $ 113,007,000
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 | $ 57,196,000 | $ 57,939,000
12 months or longer, unrealized losses | $ 4,127,000 | $ 4,356,000

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