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Debt Securities Available-for-Sale - Comparative Summary of Mortgage-Backed Securities and Other Securities Available-for-Sale) (Details) - USD ($) $ in Thousands | Jun. 30, 2022 | Dec. 31, 2021
--- | --- | ---
Debt Securities, Available-for-sale [Line Items] |  |
Amortized cost | $ 1,130,384 | $ 1,205,516
Gross unrealized gains | 71 | 7,824
Gross unrealized losses | (43,587) | (5,103)
Estimated fair value | 1,086,868 | 1,208,237
U.S. Government agency securities |  |
Debt Securities, Available-for-sale [Line Items] |  |
Amortized cost | 76,572 | 2,344
Gross unrealized gains | 0 | 0
Gross unrealized losses | (1,769) | (54)
Estimated fair value | 74,803 | 2,290
Real estate mortgage investment conduits (REMICs) |  |
Debt Securities, Available-for-sale [Line Items] |  |
Amortized cost | 855,942 | 969,790
Gross unrealized gains | 49 | 7,631
Gross unrealized losses | (34,752) | (4,305)
Estimated fair value | 821,239 | 973,116
Other debt securities |  |
Debt Securities, Available-for-sale [Line Items] |  |
Amortized cost | 197,870 | 233,382
Gross unrealized gains | 22 | 193
Gross unrealized losses | (7,066) | (744)
Estimated fair value | 190,826 | 232,831
GSE | Pass-through Certificates |  |
Debt Securities, Available-for-sale [Line Items] |  |
Amortized cost | 538,676 | 579,035
Gross unrealized gains | 49 | 5,233
Gross unrealized losses | (25,299) | (2,862)
Estimated fair value | 513,426 | 581,406
GSE | Real estate mortgage investment conduits (REMICs) |  |
Debt Securities, Available-for-sale [Line Items] |  |
Amortized cost | 317,266 | 390,755
Gross unrealized gains | 0 | 2,398
Gross unrealized losses | (9,453) | (1,443)
Estimated fair value | 307,813 | 391,710
Municipal bonds | Other debt securities |  |
Debt Securities, Available-for-sale [Line Items] |  |
Amortized cost | 52 | 71
Gross unrealized gains | 0 | 1
Gross unrealized losses | 0 | 0
Estimated fair value | 52 | 72
Corporate bonds | Other debt securities |  |
Debt Securities, Available-for-sale [Line Items] |  |
Amortized cost | 197,818 | 233,311
Gross unrealized gains | 22 | 192
Gross unrealized losses | (7,066) | (744)
Estimated fair value | $ 190,774 | $ 232,759

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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 https://asc.fasb.org/extlink&oid=126970911&loc=d3e27161-111563 + Details
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- Definition Amount, before tax, of unrealized loss 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 (c) -URI https://asc.fasb.org/extlink&oid=126970911&loc=d3e27161-111563 + Details
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