Securities - Contractual Maturity Information for Securities Held to Maturity (Detail) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Investments Debt And Equity Securities [Abstract]
Due in 1 year or less, Amortized Cost	$ 13,819
Due after 1 year through 5 years, Amortized Cost	151,022
Due after 5 years through 10 years, Amortized Cost	616,835
Due after 10 years, Amortized Cost	1,329,863
Total, Amortized cost	2,111,539
Mortgage-backed securities, Amortized cost	2,490,693
Amortized Cost	4,602,232	$ 1,480,416
Due in 1 year or less, Fair Value	13,784
Due after 1 year through 5 years, Fair Value	144,816
Due after 5 years through 10 years, Fair Value	579,542
Due after 10 years, Fair Value	1,231,111
Total, Fair value	1,969,253
Mortgage-backed securities, Fair value	2,424,202
Total securities held to maturity, Fair value	$ 4,393,455	$ 1,442,391

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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