Securities - Contractual Maturity Information for Securities Held to Maturity (Detail) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Investments, Debt and Equity Securities [Abstract]
Due in 1 year or less, Amortized Cost	$ 84,409
Due after 1 year through 5 years, Amortized Cost	328,485
Due after 5 years through 10 years, Amortized Cost	824,540
Due after 10 years, Amortized Cost	1,705,046
Total, Amortized cost	2,942,480
Mortgage-backed securities, Amortized cost	2,790,103
Amortized Cost	5,732,583	$ 5,861,599
Due in 1 year or less, Fair Value	83,964
Due after 1 year through 5 years, Fair Value	317,451
Due after 5 years through 10 years, Fair Value	757,544
Due after 10 years, Fair Value	1,419,835
Total, Fair value	2,578,794
Mortgage-backed securities, Fair value	2,277,672
Total securities held to maturity, Fair value	$ 4,856,466	$ 5,280,659

Mortgage backed securities held to maturity amortized cost.

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Amount, before allowance for credit loss, of investment in debt security measured at amortized cost (held-to-maturity).

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Fair value of securitized, pay-through debt securities collateralized by real estate mortgage loans classified as held-to-maturity.

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