COST-SAVING INITIATIVES - Expenses Associated with Cost Savings Initiatives (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2024 USD ($)
Cost Saving initiatives [Line Items]
Restructuring charges	$ 48,729
Severance and other employee termination expenses (included in "compensation and benefits" expense)
Cost Saving initiatives [Line Items]
Restructuring charges	46,610
Other
Cost Saving initiatives [Line Items]
Restructuring charges	2,119
Financial Advisory
Cost Saving initiatives [Line Items]
Restructuring charges	33,481
Financial Advisory | Severance and other employee termination expenses (included in "compensation and benefits" expense)
Cost Saving initiatives [Line Items]
Restructuring charges	32,773
Financial Advisory | Other
Cost Saving initiatives [Line Items]
Restructuring charges	708
Asset Management
Cost Saving initiatives [Line Items]
Restructuring charges	11,559
Asset Management | Severance and other employee termination expenses (included in "compensation and benefits" expense)
Cost Saving initiatives [Line Items]
Restructuring charges	11,545
Asset Management | Other
Cost Saving initiatives [Line Items]
Restructuring charges	14
Corporate
Cost Saving initiatives [Line Items]
Restructuring charges	3,689
Corporate | Severance and other employee termination expenses (included in "compensation and benefits" expense)
Cost Saving initiatives [Line Items]
Restructuring charges	2,292
Corporate | Other
Cost Saving initiatives [Line Items]
Restructuring charges	$ 1,397