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Securities - Amortized Cost and Fair Value of Debt Securities (Details) - USD ($) $ in Thousands | Mar. 31, 2022 | Dec. 31, 2021
--- | --- | ---
Debt Securities, Available-for-sale [Line Items] |  |
Amortized Cost | $ 1,065,927 | $ 900,235
Gross Unrealized Gains | 1,648 | 15,183
Gross Unrealized Losses | (40,495) | (5,767)
Fair Value | 1,027,080 | 909,651
Interest receivable | 3,500 | 3,300
U.S. Treasury securities |  |
Debt Securities, Available-for-sale [Line Items] |  |
Amortized Cost | 136,695 | 95,954
Gross Unrealized Gains | 41 | 115
Gross Unrealized Losses | (6,742) | (742)
Fair Value | 129,994 | 95,327
Obligations of U.S. government corporations and agencies |  |
Debt Securities, Available-for-sale [Line Items] |  |
Amortized Cost | 58,570 | 68,599
Gross Unrealized Gains | 179 | 1,749
Gross Unrealized Losses | (256) | 0
Fair Value | 58,493 | 70,348
Collateralized mortgage obligations of U.S. government corporations and agencies |  |
Debt Securities, Available-for-sale [Line Items] |  |
Amortized Cost | 404,626 | 270,696
Gross Unrealized Gains | 179 | 2,408
Gross Unrealized Losses | (19,203) | (2,810)
Fair Value | 385,602 | 270,294
Residential mortgage-backed securities of U.S. government corporations and agencies |  |
Debt Securities, Available-for-sale [Line Items] |  |
Amortized Cost | 54,444 | 57,029
Gross Unrealized Gains | 52 | 392
Gross Unrealized Losses | (4,050) | (628)
Fair Value | 50,446 | 56,793
Commercial mortgage-backed securities of U.S. government corporations and agencies |  |
Debt Securities, Available-for-sale [Line Items] |  |
Amortized Cost | 340,886 | 336,918
Gross Unrealized Gains | 169 | 5,969
Gross Unrealized Losses | (10,244) | (1,587)
Fair Value | 330,811 | 341,300
Corporate obligations |  |
Debt Securities, Available-for-sale [Line Items] |  |
Amortized Cost | 500 | 500
Gross Unrealized Gains | 0 | 0
Gross Unrealized Losses | 0 | 0
Fair Value | 500 | 500
Obligations of states and political subdivisions |  |
Debt Securities, Available-for-sale [Line Items] |  |
Amortized Cost | 70,206 | 70,539
Gross Unrealized Gains | 1,028 | 4,550
Gross Unrealized Losses | 0 | 0
Fair Value | $ 71,234 | $ 75,089

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- Definition Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=123581744&loc=d3e27161-111563 + Details
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