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.

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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
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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.

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Benefit Plans - Plan Assets Allocation (Details) - Pension Plan	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Benefit Plans
Asset Allocation (as a percent)	100.00%	100.00%
Expected long term return on plan assets (as a percent)	4.75%	3.05%	2.75%
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)	86.00%	87.00%
Target Allocation (as a percent)	88.00%
Other securities
Benefit Plans
Asset Allocation (as a percent)	3.00%	2.00%
Target Allocation (as a percent)	2.00%