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Commitments and Contingencies (Details) - USD ($) | 12 Months Ended
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Dec. 31, 2025 | Dec. 31, 2024 | Dec. 31, 2023
Commitments And Contingencies [Line Items] |  |  |
Letters of credit outstanding | $ 520,200,000 | $ 503,400,000 |
Mortgage loans sold | 2,585,949,000 | 2,609,248,000 | $ 1,963,214,000
Liability for estimated losses on repurchase and indemnification claims | 578,000 | 188,000 |
Losses charged against liability | 117,100 | 60,100 |
Unfunded commitments to investment partnerships | 160,700,000 | 94,100,000 |
Commitments to invest in partnership for tax credits | 126,300,000 | 67,000,000.0 |
Forward contracts |  |  |
Commitments And Contingencies [Line Items] |  |  |
Derivative instrument, contractual amounts | 413,200,000 | 377,500,000 |
Commercial, commercial real estate, and construction loans | Commitments to extend credit |  |  |
Commitments And Contingencies [Line Items] |  |  |
Commitments to fund | 11,800,000,000 | 11,500,000,000 |
Unused home equity lines | Commitments to extend credit |  |  |
Commitments And Contingencies [Line Items] |  |  |
Commitments to fund | 1,000,000,000.0 | 999,100,000 |
Residential real estate | Commitments to extend credit |  |  |
Commitments And Contingencies [Line Items] |  |  |
Commitments to fund | $ 423,600,000 | $ 361,300,000 |

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- Definition The total amount of the contingent obligation under letters of credit outstanding as of the reporting date. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 944 -SubTopic 605 -Name Accounting Standards Codification -Section 55 -Paragraph 15 -Publisher FASB -URI https://asc.fasb.org/1943274/2147477548/944-605-55-15 Reference 2: http://www.xbrl.org/2003/role/exampleRef -Topic 944 -SubTopic 605 -Name Accounting Standards Codification -Section 55 -Paragraph 12 -Publisher FASB -URI https://asc.fasb.org/1943274/2147477548/944-605-55-12 + Details
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- Definition Minimum amount of other commitment not otherwise specified in the taxonomy. Excludes commitments explicitly modeled in the taxonomy, including but not limited to, long-term and short-term purchase commitments, recorded and unrecorded purchase obligations, supply commitments, registration payment arrangements, leases, debt, product warranties, guarantees, environmental remediation obligations, and pensions. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 942 -SubTopic 235 -Name Accounting Standards Codification -Section S99 -Paragraph 2 -Publisher FASB -URI https://asc.fasb.org/1943274/2147477314/942-235-S99-2 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 235 -SubTopic 10 -Name Accounting Standards Codification -Section S50 -Paragraph 4 -Publisher FASB -URI https://asc.fasb.org/1943274/2147480738/235-10-S50-4 Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 235 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 3 -Subparagraph (SX 210.12-04(a)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480678/235-10-S99-3 + Details
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- Definition Amount of commitment and contingent commitment, including amount of delayed equity contribution, for investment that generates income tax credit and other income tax benefit under tax credit program elected to be accounted for using proportional amortization method. Includes, but is not limited to, commitment and contingent commitment related to investment under tax credit program not meeting condition for accounting under proportional amortization method. + References Reference 1: http://www.xbrl.org/2003/role/recommendedDisclosureRef -Topic 740 -SubTopic 323 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (e) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478156/740-323-50-2 + Details
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- Definition Liability for loss indemnification claims on residential mortgage loans previously sold to investors. + References No definition available. + Details
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