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Securities - Schedule of Amortized Cost and Fair Value of Debt Securities by Contractual Maturity (Details) - USD ($) $ in Thousands | Dec. 31, 2019 | Dec. 31, 2018
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Available-for-sale Securities Debt Maturities, Amortized Cost [Abstract] |  |
Available-for-sale Securities, Due in one year or less, Amortized Cost | $ 51,901 |
Available-for-sale Securities, Due from one to five years, Amortized Cost | 99,605 |
Available-for-sale Securities, Due from five to ten years, Amortized Cost | 136,479 |
Available-for-sale Securities, Due after ten years, Amortized Cost | 104,697 |
Available-for-sale Securities, Amortized Cost | 1,183,404 | $ 834,254
Held-to-maturity Securities Debt Maturities, Amortized Cost [Abstract] |  |
Held-to-maturity Securities, Due from one to five years, Amortized Cost | 3,800 |
Held-to-maturity Securities, Due from five to ten years, Amortized Cost | 612 |
Held-to-maturity Securities, Amortized Cost | 4,412 | 99,266
Available-for-sale Securities Debt Maturities, Fair Value [Abstract] |  |
Available-for-sale Securities, Due in one year or less, Fair Value | 52,093 |
Available-for-sale Securities, Due from one to five years, Fair Value | 100,593 |
Available-for-sale Securities, Due from five to ten years, Fair Value | 137,843 |
Available-for-sale Securities, Due after ten years, Fair Value | 104,730 |
Available-for-sale Securities, Fair Value, Total | 1,186,292 | 817,656
Held-to-maturity Securities Debt Maturities, Fair Value [Abstract] |  |
Held-to-maturity Securities, Due from one to five years, Fair Value | 3,866 |
Held-to-maturity Securities, Due from five to ten years, Fair Value | 632 |
Held-to-maturity securities, Fair Value, Total | 4,498 | $ 97,739
Mortgage and Asset-Backed Securities |  |
Available-for-sale Securities Debt Maturities, Amortized Cost [Abstract] |  |
Available-for-sale Securities, Not due at single maturity, Amortized Cost | 790,722 |
Available-for-sale Securities Debt Maturities, Fair Value [Abstract] |  |
Available-for-sale Securities, Not due at single maturity, Fair Value | $ 791,033 |

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- Definition Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), with single maturity date and allocated without single maturity date, maturing in second through fifth fiscal year following latest fiscal year. Excludes interim and annual periods when interim period is reported on rolling approach, from latest statement of financial position date. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 3 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=118939692&loc=d3e27198-111563 + Details
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