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Securities, HTM Debt Securities, Contractual Maturities (Details) $ in Thousands | Jun. 30, 2021 USD ($) Issuer | Dec. 31, 2020 USD ($) Issuer
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Held-to-maturity Securities, Debt Maturities, Amortized Cost [Abstract] |  |
Within one year | $ 51,610 |
From one to five years | 54,875 |
From five to ten years | 227,013 |
After ten years | 288,853 |
Amortized cost | 622,351 | $ 616,560
Held-to-maturity Securities, Debt Maturities, Estimated Fair Value [Abstract] |  |
Within one year | 51,659 |
From one to five years | 56,215 |
From five to ten years | 229,266 |
After ten years | 295,814 |
Fair value | $ 632,954 | $ 636,827
Number of issuers whose holdings exceeded 10% of consolidated stockholders' equity, excluding U.S. Government securities and Government-sponsored enterprises securities | Issuer | 0 | 0

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- Definition Amount, before allowance for credit loss, of investment in debt security measured at amortized cost (held-to-maturity). + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 20 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=124255206&loc=SL82895884-210446 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 20 -Section 50 -Paragraph 14 -URI http://asc.fasb.org/extlink&oid=124255953&loc=SL82919253-210447 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 7A -URI http://asc.fasb.org/extlink&oid=123577603&loc=SL6953401-111524 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 5 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=123581744&loc=d3e27232-111563 + Details
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