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Investment Securities - Available-for-Sale Securities Amortized Cost and Fair Value (Details) - USD ($) | Dec. 31, 2021 | Dec. 31, 2020
--- | --- | ---
Debt Securities, Available-for-sale [Line Items] |  |  |
Amortized Cost |  | $ 1,169,520,000 | $ 373,038,000
Gross Unrealized Gains |  | 11,074,000 | 19,393,000
Gross Unrealized (Losses) |  | (13,026,000) | (80,000)
Allowance for Credit Losses | [1] | 0 | 0
Securities available for sale, Fair Value |  | 1,167,568,000 | 392,351,000
Other assets |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |
Accrued interest |  | 3,700,000 | 1,900,000
MBS pass-through securities issued by FHLMC and FNMA |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |
Amortized Cost |  | 316,090,000 | 50,686,000
Gross Unrealized Gains |  | 1,224,000 | 2,530,000
Gross Unrealized (Losses) |  | (2,784,000) | 0
Allowance for Credit Losses |  | 0 | 0
Securities available for sale, Fair Value |  | 314,530,000 | 53,216,000
CMOs issued by FHLMC |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |
Amortized Cost |  | 343,047,000 | 143,267,000
Gross Unrealized Gains |  | 3,209,000 | 7,925,000
Gross Unrealized (Losses) |  | (4,829,000) | (1,000)
Allowance for Credit Losses |  | 0 | 0
Securities available for sale, Fair Value |  | 341,427,000 | 151,191,000
CMOs issued by FNMA |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |
Amortized Cost |  | 48,187,000 | 16,450,000
Gross Unrealized Gains |  | 152,000 | 580,000
Gross Unrealized (Losses) |  | (611,000) | 0
Allowance for Credit Losses |  | 0 | 0
Securities available for sale, Fair Value |  | 47,728,000 | 17,030,000
CMOs issued by GNMA |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |
Amortized Cost |  | 56,345,000 | 6,863,000
Gross Unrealized Gains |  | 99,000 | 351,000
Gross Unrealized (Losses) |  | (553,000) | 0
Allowance for Credit Losses |  | 0 | 0
Securities available for sale, Fair Value |  | 55,891,000 | 7,214,000
SBA-backed securities |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |
Amortized Cost |  | 32,640,000 | 30,941,000
Gross Unrealized Gains |  | 993,000 | 1,976,000
Gross Unrealized (Losses) |  | (155,000) | (55,000)
Allowance for Credit Losses |  | 0 | 0
Securities available for sale, Fair Value |  | 33,478,000 | 32,862,000
Debentures of government sponsored agencies |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |
Amortized Cost |  | 191,449,000 | 19,944,000
Gross Unrealized Gains |  | 25,000 | 266,000
Gross Unrealized (Losses) |  | (2,947,000) | (24,000)
Allowance for Credit Losses |  | 0 | 0
Securities available for sale, Fair Value |  | 188,527,000 | 20,186,000
U.S. Treasury securities |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |
Amortized Cost |  | 11,886,000 |
Gross Unrealized Gains |  | 0 |
Gross Unrealized (Losses) |  | (256,000) |
Allowance for Credit Losses |  | 0 |
Securities available for sale, Fair Value |  | 11,630,000 |
Obligations of state and political subdivisions |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |
Amortized Cost |  | 129,009,000 | 104,887,000
Gross Unrealized Gains |  | 5,372,000 | 5,765,000
Gross Unrealized (Losses) |  | (381,000) | 0
Allowance for Credit Losses |  | 0 | 0
Securities available for sale, Fair Value |  | 134,000,000 | $ 110,652,000
Corporate bonds |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |
Amortized Cost |  | 39,001,000 |
Gross Unrealized Gains |  | 0 |
Gross Unrealized (Losses) |  | (506,000) |
Allowance for Credit Losses |  | 0 |
Securities available for sale, Fair Value |  | 38,495,000 |
Asset-backed securities |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |
Amortized Cost |  | 1,866,000 |
Gross Unrealized Gains |  | 0 |
Gross Unrealized (Losses) |  | (4,000) |
Allowance for Credit Losses |  | 0 |
Securities available for sale, Fair Value |  | $ 1,862,000 |
[1] | Refer to Note 1, Summary of Accounting Policies, for information on the adoption of ASU 2016-13 in 2020.

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