Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Cash Flows From Operating Activities
Net Income	$ 640,707	$ 417,737	$ 285,223
Adjustments to Reconcile Net Income to Net Cash Provided by (Used In) Operating Activities:
Net (Gains) Losses on Investments, Investment Securities and Contingent Consideration	(24,082)	(33,682)	(34,671)
Equity Method Investments, Including (Gains) Losses on Sales and Redemptions	(112)	7,385	(192)
Equity-Based and Other Deferred Compensation	675,100	569,734	515,381
Noncash Lease Expense	49,798	41,792	42,153
Depreciation, Amortization and Accretion, net	10,537	(387)	2,388
Bad Debt Expense	5,635	2,334	5,559
Deferred Taxes	15,086	8,074	(2,894)
Decrease (Increase) in Operating Assets:
Investment Securities	23,918	30,839	11,635
Accounts Receivable	(124,587)	(54,589)	11,273
Receivable from Employees and Related Parties	(4,916)	(7,919)	(3,758)
Other Assets	(131,447)	6,797	(4,759)
(Decrease) Increase in Operating Liabilities:
Accrued Compensation and Benefits	176,881	17,754	(325,732)
Accounts Payable and Accrued Expenses	14,489	1,743	(966)
Payables to Employees and Related Parties	16,053	5,446	(8,734)
Taxes Payable	11,161	(643)	(4,557)
Other Liabilities	(97,757)	(24,264)	(29,395)
Net Cash Provided by Operating Activities	1,256,464	988,151	457,954
Cash Flows From Investing Activities
Investments Purchased	(1,000)	(22)	(37)
Proceeds from Sale of Investments	0	18,113	0
Distributions of Private Equity Investments	1,887	0	105
Investment Securities:
Proceeds from Sales and Maturities of Investment Securities	3,247,890	3,066,469	3,279,088
Purchases of Investment Securities	(3,310,862)	(3,108,767)	(3,313,200)
Maturity of Certificates of Deposit	202,950	172,297	177,446
Purchase of Certificates of Deposit	(177,348)	(185,420)	(107,733)
Cash Acquired for Acquisitions, net of Cash Paid	12,160	0	0
Purchase of Furniture, Equipment and Leasehold Improvements	(74,002)	(30,101)	(20,048)
Net Cash Provided by (Used in) Investing Activities	(98,325)	(67,431)	15,621
Cash Flows From Financing Activities
Issuance of Noncontrolling Interests	1,331	85	733
Distributions to Noncontrolling Interests	(30,731)	(30,848)	(27,293)
Payments Under Tax Receivable Agreement	(11,371)	(11,427)	(10,843)
Payment of Notes Payable	(38,000)	0	0
Issuance of Notes Payable	250,000	0	0
Debt Issuance Costs	(662)	0	0
Purchase of Treasury Stock and Noncontrolling Interests	(661,780)	(450,530)	(391,964)
Dividends	(144,410)	(135,832)	(127,864)
Net Cash Provided by (Used in) Financing Activities	(635,623)	(628,552)	(557,231)
Effect of Exchange Rate Changes on Cash	31,517	(15,545)	17,017
Net Increase (Decrease) in Cash, Cash Equivalents and Restricted Cash	554,033	276,623	(66,639)
Cash, Cash Equivalents and Restricted Cash – Beginning of Period	882,107	605,484	672,123
Cash, Cash Equivalents and Restricted Cash – End of Period	1,436,140	882,107	605,484
SUPPLEMENTAL CASH FLOW DISCLOSURE
Payments for Interest	19,896	16,214	16,181
Payments for Income Taxes	117,312	98,201	74,639
Accrued Dividends	15,537	16,159	17,054
Redemption of Luminis Interest	0	7,305	0
Contingent Consideration Accrued	24,521	0	0
Shares Issued as Consideration for Acquisitions	95,767	0	0
Deferred Purchase Price Payable in Shares or Cash for Acquisitions	94,893	0
Assets Acquired in Acquisitions	27,906	0	0
Liabilities Assumed in Acquisitions	$ 27,906	$ 0	$ 0