Securities - Carrying Value and Estimated Fair Value of Available-for-Sale Securities (Detail) - USD ($) $ in Thousands |
Jun. 30, 2026 |
Dec. 31, 2025 |
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| Investments, Debt and Equity Securities [Abstract] | ||
| Total | $ 6,030,335 | $ 5,856,138 |
| Due within one year | 215,741 | |
| Due after one year through five years | 2,989,929 | |
| Due after five years through ten years | 1,741,307 | |
| Due after ten years | 1,083,358 | |
| Total | 6,030,335 | |
| Available-for-Sale, Estimated Fair Value, Due within one year | 214,485 | |
| Available-for-Sale, Estimated Fair Value, Due after one year through five years | 2,856,312 | |
| Available-for-Sale, Estimated Fair Value, Due after five years through ten years | 1,663,449 | |
| Available-for-Sale, Estimated Fair Value, Due after ten years | 941,711 | |
| Available-for-Sale, Estimated Fair Value, Total | $ 5,675,957 | $ 5,514,113 |
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- Definition Available For Sale Debt Securities No definition available.
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- Definition Available For Sale Securities Debt Maturities After Five Through Ten Years No definition available.
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- Definition Available for sale securities debt maturities after one through five years No definition available.
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- Definition Available for sale securities debt maturities after ten years No definition available.
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- Definition Available For Sale Securities Debt Maturities With In One Year No definition available.
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- Definition Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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- Definition Fair value of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), with single maturity date and allocated without single maturity date, maturing in sixth through tenth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach). Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Fair value of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), with single maturity date and allocated without single maturity date, maturing in second through fifth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach). Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Fair value of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), with single maturity date and allocated without single maturity date, maturing after tenth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach). Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Fair value of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), with single maturity date and allocated without single maturity date, maturing in next fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach). Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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- References No definition available.
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