Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Operating Activities
Net Income	$ 164,772	$ 189,955	$ 212,426
Adjustments to Reconcile Net Income to Net Cash Provided by Operating Activities
Equity-Based Compensation Expense	165,528	108,913	120,912
Depreciation and Amortization Expense	15,475	15,750	15,055
Amortization of Operating Lease Right-of-Use Assets	20,735	19,175	21,305
Deferred Taxes	1,784	7,096	6,911
Provision for Credit Losses	2,817	2,869	1,266
Other	2,793	(4,674)	(4,281)
Cash Flows Due to Changes in Operating Assets and Liabilities
Accounts Receivable	(32,497)	(61,034)	(4,943)
Other Assets	(42,659)	(3,060)	(6,490)
Accrued Compensation and Benefits	(35,347)	(131,388)	129,618
Accounts Payable, Accrued Expenses and Other Liabilities	1,658	(2,073)	818
Operating Lease Liabilities	(22,488)	(21,397)	(16,596)
Taxes Payable	105	847	(2,133)
Deferred Revenue	55	3,182	(4,426)
Net Cash Provided by Operating Activities	242,731	124,161	469,442
Investing Activities
Purchases of Investments	(143,929)	(97,638)	(278,060)
Proceeds from Sales and Maturities of Investments	94,128	235,457	141,162
Purchases of Furniture, Equipment and Leasehold Improvements	(3,434)	(6,472)	(8,854)
Net Cash Provided by (Used in) Investing Activities	(53,235)	131,347	(145,752)
Financing Activities
Dividends	(24,632)	(77,974)	(4,819)
Proceeds from Revolving Credit Facility	42,000	15,000	16,000
Payments on Revolving Credit Facility	(42,000)	(15,000)	(16,000)
Principal Payments on Term Loan			(21,500)
Tax Distributions	(38,338)	(37,830)	(54,685)
Employee Taxes Paid for Shares Withheld	(17,792)	(22,773)	(12,704)
Cash-Settled Exchanges of Partnership Units	(15,120)	(109,574)	(101,895)
Treasury Stock Purchases	(109,484)	(103,342)	(48,674)
Payments Pursuant to Tax Receivable Agreement	(4,655)	(1,890)
Net Cash Used in Financing Activities	(210,021)	(353,383)	(244,277)
Effect of Exchange Rate Changes on Cash and Cash Equivalents	(6,721)	(1,157)	4,150
Net Increase (Decrease) in Cash and Cash Equivalents	(27,246)	(99,032)	83,563
Cash and Cash Equivalents, Beginning of Period	200,481	299,513	215,950
Cash and Cash Equivalents, End of Period	173,235	200,481	299,513
Supplemental Disclosure of Cash Flows Information
Payments for Income Taxes, Net of Refunds Received	28,578	30,933	36,161
Payments for Interest	$ 133	10	116
Non-Cash Receipt of Shares		$ 1,125	$ 1,138