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Investment Securities - Held-to-Maturity Securities Amortized Cost and Fair Value (Details) - USD ($) | Dec. 31, 2020 | Dec. 31, 2019
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Debt Securities, Held-to-maturity [Abstract] |  |
Amortized Cost | $ 109,036,000 | $ 137,413,000
Allowance for Credit Losses | 0 | 0
Net Carrying Amount | 109,036,000 | 137,413,000
Gross Unrealized Gains | 6,149,000 | 2,378,000
Gross Unrealized (Losses) | 0 | (149,000)
Fair Value | 115,185,000 | 139,642,000
Other assets |  |
Debt Securities, Held-to-maturity [Abstract] |  |
Accrued interest | 366,000 | 469,000
MBS pass-through securities issued by FHLMC and FNMA |  |
Debt Securities, Held-to-maturity [Abstract] |  |
Amortized Cost | 65,579,000 | 80,451,000
Allowance for Credit Losses | 0 | 0
Net Carrying Amount | 65,579,000 | 80,451,000
Gross Unrealized Gains | 3,924,000 | 1,018,000
Gross Unrealized (Losses) | 0 | (144,000)
Fair Value | 69,503,000 | 81,325,000
CMOs issued by FHLMC |  |
Debt Securities, Held-to-maturity [Abstract] |  |
Amortized Cost | 27,201,000 | 31,477,000
Allowance for Credit Losses | 0 | 0
Net Carrying Amount | 27,201,000 | 31,477,000
Gross Unrealized Gains | 1,441,000 | 685,000
Gross Unrealized (Losses) | 0 | (5,000)
Fair Value | 28,642,000 | 32,157,000
CMOs issued by FNMA |  |
Debt Securities, Held-to-maturity [Abstract] |  |
Amortized Cost | 8,042,000 | 10,210,000
Allowance for Credit Losses | 0 | 0
Net Carrying Amount | 8,042,000 | 10,210,000
Gross Unrealized Gains | 363,000 | 282,000
Gross Unrealized (Losses) | 0 | 0
Fair Value | 8,405,000 | 10,492,000
CMOs issued by GNMA |  |
Debt Securities, Held-to-maturity [Abstract] |  |
Amortized Cost |  | 3,763,000
Allowance for Credit Losses |  | 0
Net Carrying Amount |  | 3,763,000
Gross Unrealized Gains |  | 53,000
Gross Unrealized (Losses) |  | 0
Fair Value |  | 3,816,000
SBA-backed securities |  |
Debt Securities, Held-to-maturity [Abstract] |  |
Amortized Cost | 6,547,000 | 7,999,000
Allowance for Credit Losses | 0 | 0
Net Carrying Amount | 6,547,000 | 7,999,000
Gross Unrealized Gains | 400,000 | 265,000
Gross Unrealized (Losses) | 0 | 0
Fair Value | 6,947,000 | 8,264,000
Obligations of state and political subdivisions |  |
Debt Securities, Held-to-maturity [Abstract] |  |
Amortized Cost | 1,667,000 | 3,513,000
Allowance for Credit Losses | 0 | 0
Net Carrying Amount | 1,667,000 | 3,513,000
Gross Unrealized Gains | 21,000 | 75,000
Gross Unrealized (Losses) |  | 0
Fair Value | $ 1,688,000 | $ 3,588,000

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- Definition Amount, before allowance for credit loss, of accrued interest on investment in debt security measured at amortized cost (held-to-maturity). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 20 -Section 50 -Paragraph 3B -URI http://asc.fasb.org/extlink&oid=121599337&loc=SL120267963-210447 + Details
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