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Securities - Amortized Cost and Fair Value (Details) $ in Thousands | 12 Months Ended |
--- | --- | ---
Dec. 31, 2021 USD ($) item | Dec. 31, 2020 USD ($)
Securities Available-for-Sale |  |
Amortized Cost | $ 1,677,016 | $ 471,961
Gross Unrealized Gains | 20,587 | 26,735
Gross Unrealized Losses | (5,115) | (2,518)
Debt Securities, Available-for-sale, Total | 1,692,488 | 496,178
Accrued interest receivable | 4,300 | 2,700
FHLB and FRB Stock |  |
FHLBC stock | 7,100 | 3,700
FRB stock | 6,200 | 6,200
Securities pledged to secure deposits and for other purposes | 501,300 | 335,800
Other disclosures |  |
Debt Securities, Available-for-sale, Total | $ 1,692,488 | 496,178
Number of securities issued from originators | 0 |
Number of originators | item | 1 |
Minimum percentage of securities investment | 10.00% |
Reimbursement requests greater than 5 % |  |
Other disclosures |  |
Percentage of outstanding principal amount of loans guaranteed by US Department of Education | 85 |
Percent of insured loan | 5 |
Reimbursement requests greater than 9 % |  |
Other disclosures |  |
Percentage of outstanding principal amount of loans guaranteed by US Department of Education | 75 |
Percent of insured loan | 9 |
US Treasury Securities |  |
Securities Available-for-Sale |  |
Amortized Cost | $ 202,251 | 4,014
Gross Unrealized Gains | 125 | 103
Gross Unrealized Losses | (37) |
Debt Securities, Available-for-sale, Total | 202,339 | 4,117
Other disclosures |  |
Debt Securities, Available-for-sale, Total | 202,339 | 4,117
US Government Corporations and Agencies Securities |  |
Securities Available-for-Sale |  |
Amortized Cost | 62,587 | 6,811
Gross Unrealized Losses | (699) | (154)
Debt Securities, Available-for-sale, Total | 61,888 | 6,657
Other disclosures |  |
Debt Securities, Available-for-sale, Total | 61,888 | 6,657
U.S. government agencies mortgage-backed |  |
Securities Available-for-Sale |  |
Amortized Cost | 172,016 | 16,098
Gross Unrealized Gains | 856 | 1,112
Gross Unrealized Losses | (570) | (1)
Debt Securities, Available-for-sale, Total | 172,302 | 17,209
Other disclosures |  |
Debt Securities, Available-for-sale, Total | 172,302 | 17,209
States and political subdivisions |  |
Securities Available-for-Sale |  |
Amortized Cost | 240,793 | 229,352
Gross Unrealized Gains | 16,344 | 21,269
Gross Unrealized Losses | (672) | (1,362)
Debt Securities, Available-for-sale, Total | 256,465 | 249,259
Other disclosures |  |
Debt Securities, Available-for-sale, Total | 256,465 | 249,259
Corporate bonds |  |
Securities Available-for-Sale |  |
Amortized Cost | 10,000 |
Gross Unrealized Losses | (113) |
Debt Securities, Available-for-sale, Total | 9,887 |
Other disclosures |  |
Debt Securities, Available-for-sale, Total | 9,887 |
Collateralized loan obligations |  |
Securities Available-for-Sale |  |
Amortized Cost | 673,238 | 53,999
Gross Unrealized Gains | 2,014 | 2,866
Gross Unrealized Losses | (2,285) | (280)
Debt Securities, Available-for-sale, Total | 672,967 | 56,585
Other disclosures |  |
Debt Securities, Available-for-sale, Total | 672,967 | 56,585
Asset-backed Securities |  |
Securities Available-for-Sale |  |
Amortized Cost | 236,293 | 130,959
Gross Unrealized Gains | 1,245 | 1,370
Gross Unrealized Losses | (661) | (511)
Debt Securities, Available-for-sale, Total | 236,877 | 131,818
Other disclosures |  |
Debt Securities, Available-for-sale, Total | 236,877 | 131,818
FFEL |  |
Securities Available-for-Sale |  |
Debt Securities, Available-for-sale, Total | 194,400 |
Other disclosures |  |
Debt Securities, Available-for-sale, Total | $ 194,400 |
Percentage of outstanding principal amount of loans guaranteed by US Department of Education | 97 |
Collateralized loan obligations. |  |
Securities Available-for-Sale |  |
Amortized Cost | $ 79,838 | 30,728
Gross Unrealized Gains | 3 | 15
Gross Unrealized Losses | (78) | (210)
Debt Securities, Available-for-sale, Total | 79,763 | 30,533
Other disclosures |  |
Debt Securities, Available-for-sale, Total | $ 79,763 | $ 30,533
Loan receivables | GCO Education Loan Funding Corp | Customer Concentration Risk |  |
Other disclosures |  |
Percentage of concentration risk | 1.00% |

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