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Benefit Plans - Plan Assets Allocation (Details) - Pension Plan [Member] | 12 Months Ended
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Dec. 31, 2024 | Dec. 31, 2023 | Dec. 31, 2022
Benefit Plans |  |  |
Asset Allocation (as a percent) | 100.00% | 100.00% |
Expected long term return on plan assets (as a percent) | 4.75% | 4.75% | 3.05%
Equity securities |  |  |
Benefit Plans |  |  |
Asset Allocation (as a percent) | 11.00% | 11.00% |
Target Allocation (as a percent) | 10.00% |  |
FHI stock |  |  |
Benefit Plans |  |  |
Asset Allocation (as a percent) | 0.00% | 0.00% |
BNP Paribas stock |  |  |
Benefit Plans |  |  |
Asset Allocation (as a percent) | 0.00% | 0.00% |
Debt securities |  |  |
Benefit Plans |  |  |
Asset Allocation (as a percent) | 85.00% | 86.00% |
Target Allocation (as a percent) | 88.00% |  |
Other securities |  |  |
Benefit Plans |  |  |
Asset Allocation (as a percent) | 4.00% | 3.00% |
Target Allocation (as a percent) | 2.00% |  |

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- Definition Weighted average rate of return on plan assets, reflecting average rate of earnings expected on existing plan assets and expected contributions, used to determine net periodic benefit cost of defined benefit plan. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 8 -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-8 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (k)(3) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-1 + Details
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
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- Definition Percentage of target investment allocation to total plan assets. Includes, but is not limited to, percentage on weighted-average basis if more than one plan. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 17 -Publisher FASB -URI https://asc.fasb.org/1943274/2147480482/715-20-55-17 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (d)(i) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-1 + Details
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- Definition Percentage of actual investment allocation to total plan assets. Includes, but is not limited to, percentage on weighted-average basis if more than one plan. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (d)(i) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-1 + Details
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