Segment Reporting - Summary of Segment Information (Details) - USD ($) $ in Thousands |
3 Months Ended | 9 Months Ended | ||||||
|---|---|---|---|---|---|---|---|---|
Sep. 30, 2026 |
Jun. 30, 2026 |
Mar. 31, 2026 |
Sep. 30, 2025 |
Jun. 30, 2025 |
Mar. 31, 2025 |
Sep. 30, 2026 |
Sep. 30, 2025 |
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| Segment Reporting [Line Items] | ||||||||
| Net commissions and fees | $ 775,081 | $ 739,552 | $ 2,460,712 | $ 2,256,537 | ||||
| Fiduciary investment income | 14,882 | 15,025 | 41,127 | 43,376 | ||||
| Total revenue | 789,963 | 754,577 | 2,501,839 | 2,299,913 | ||||
| General and administrative expense | 106,977 | 117,589 | 334,381 | 330,698 | ||||
| Change in contingent consideration | (10,658) | 11,968 | 34,187 | (2,833) | ||||
| Interest income | (1,400) | (1,700) | (4,200) | (6,300) | ||||
| Income from equity method investments | (11,840) | (4,957) | (24,410) | (15,050) | ||||
| Other non-operating income | (784) | (402) | (1,520) | (636) | ||||
| Income tax expense (benefit) | 8,140 | (2,797) | 36,998 | 65,659 | ||||
| NET INCOME | 88,048 | $ 108,381 | $ 40,597 | 62,603 | $ 124,705 | $ (4,389) | 237,026 | 182,919 |
| Reporting Segment | ||||||||
| Segment Reporting [Line Items] | ||||||||
| Net commissions and fees | 775,081 | 739,552 | 2,460,712 | 2,256,537 | ||||
| Fiduciary investment income | 14,882 | 15,025 | 41,127 | 43,376 | ||||
| Total revenue | 789,963 | 754,577 | 2,501,839 | 2,299,913 | ||||
| Compensation-related expense | 443,373 | 417,217 | 1,400,151 | 1,268,059 | ||||
| General and administrative expense | 102,144 | 101,827 | 298,306 | 287,414 | ||||
| Other segment items | 45,668 | 38,979 | 146,925 | 131,220 | ||||
| Depreciation and amortization | 68,608 | 73,795 | 206,530 | 213,975 | ||||
| Change in contingent consideration | (10,658) | 11,968 | 34,187 | (2,833) | ||||
| Interest income | (1,381) | (1,749) | (4,180) | (6,334) | ||||
| Interest expense | 58,645 | 58,093 | 171,826 | 175,520 | ||||
| Income from equity method investments | (11,840) | (4,957) | (24,410) | (15,050) | ||||
| Other non-operating income | (784) | (402) | (1,520) | (636) | ||||
| Income tax expense (benefit) | $ 8,140 | $ (2,797) | $ 36,998 | $ 65,659 | ||||
| X | ||||||||||
- Definition Compensation Expense, Excluding Cost of Good and Service Sold and Other No definition available.
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| X | ||||||||||
- Definition Amount of increase (decrease) in value of liability in contingent consideration arrangement in business combination, including, but not limited to, difference arising upon settlement. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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| X | ||||||||||
- Definition The aggregate expense recognized in the current period that allocates the cost of tangible assets, intangible assets, or depleting assets to periods that benefit from use of the assets. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Definition The aggregate total of expenses of managing and administering the affairs of an entity, including affiliates of the reporting entity, which are not directly or indirectly associated with the manufacture, sale or creation of a product or product line. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Definition Amount of income (loss) for proportionate share of equity method investee's income (loss). Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Definition Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Amount of interest expense classified as nonoperating. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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| X | ||||||||||
- Definition Amount of interest income from interest-earning asset. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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- Definition Amount after accretion (amortization) of discount (premium), and investment expense, of interest income and dividend income on nonoperating securities. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Definition Amount of income (expense) related to nonoperating activities, classified as other. Reference 1: http://www.xbrl.org/2003/role/exampleRef
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- Definition The consolidated profit or loss for the period, net of income taxes, including the portion attributable to the noncontrolling interest. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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| X | ||||||||||
- Definition Amount, excluding tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value added and excise. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss). Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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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. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Amount of other expense (income) and loss (gain) calculated as difference between segment revenue and separately disclosed expense category to arrive at segment profit (loss). Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Details
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