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Investment Securities - Additional Information (Detail) $ in Thousands | 12 Months Ended
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Dec. 31, 2021 USD ($) Security | Dec. 31, 2020 USD ($) | Dec. 31, 2019 USD ($)
Debt Securities, Available-for-sale [Line Items] |  |  |
Number of securities in an unrealized loss positions | Security | 66 |  |
Corporate/Mortgage-Backed Securities, Amortized cost | $ 1,045,579 | $ 805,515 |
Securities available for sale | 1,041,380 | 831,223 |
Other investments | 11,700 | 10,600 |
Equity Securities, FV-NI | 1,200 | 1,700 |
Gross Unrealized Gains (Losses) | 13,714 | 0 |
Amortized Cost | 1,045,579 | 805,515 |
Held-to-maturity Securities [Member] |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |
Pledged Financial Instruments, Not Separately Reported, Other Debt Securities Available-for-sale or Held-for-investment | 313,900 | 228,100 |
Available-for-sale Securities [Member] |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |
Pledged Financial Instruments, Not Separately Reported, Other Debt Securities Available-for-sale or Held-for-investment | 759,100 | 792,100 |
Corporate Securities [Member] |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |
Corporate/Mortgage-Backed Securities, Amortized cost | 32,088 | 22,941 |
Securities available for sale | 32,949 | 24,385 |
Gross Unrealized Gains (Losses) | 112 | 0 |
Amortized Cost | 32,088 | 22,941 |
Sales [Member] |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |
Available-for-sale Securities, Gross Realized Losses | 0 | 0 | $ 0
Available-for-sale Securities, Gross Realized Losses | 0 | 0 | 7
Available-for-sale Securities, Gross Realized Gain (Loss), Excluding Other than Temporary Impairments | 0 | 0 | (7)
Calls And Maturities [Member] |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |
Gross Gains | 16 | 70 | 29
Available-for-sale Securities, Gross Realized Losses | 0 | 0 | 0
Gain Losses Maturities And Impairment | $ 16 | $ 70 | $ 29

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- Definition Federal Home Loan Bank (FHLB) stock represents an equity interest in a FHLB. It does not have a readily determinable fair value because its ownership is restricted and it lacks a market (liquidity). + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 325 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=123599499&loc=d3e63345-112809 + Details
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