Consolidated Statements of Financial Condition (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Statement of Financial Position [Abstract]
Investments attributable to noncontrolling interests	$ 234,167	$ 211,096
Accumulated depreciation and amortization on fixed assets	95,534	91,378
Accumulated amortization on intangible assets	$ 152,848	$ 150,487
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	100,000,000	100,000,000
Common stock, shares issued (in shares)	19,553,656	19,553,101
Common stock, shares outstanding (in shares)	15,642,422	15,200,149
Common stock held in treasury, shares (in shares)	3,911,234	4,352,952