Business Segment Information - Net Revenues Derived From Investment Management, Research and Related Services (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Revenues:
Total revenues	$ 1,104,569	$ 1,049,756	$ 2,202,693	$ 2,177,624
Less: Broker-dealer related Interest expense	15,662	21,813	33,179	45,530
Net revenues	1,088,907	1,027,943	2,169,514	2,132,094
Reportable Segment
Revenues:
Total revenues	1,104,569	1,049,756	2,202,693	2,177,624
Less: Broker-dealer related Interest expense	15,662	21,813	33,179	45,530
Net revenues	1,088,907	1,027,943	2,169,514	2,132,094
Institutions | Reportable Segment
Revenues:
Total revenues	163,018	158,779	335,023	316,052
Retail | Reportable Segment
Revenues:
Total revenues	603,176	566,671	1,203,148	1,102,848
Private Wealth Management | Reportable Segment
Revenues:
Total revenues	297,428	287,138	596,225	565,446
Bernstein Research Services | Reportable Segment
Revenues:
Total revenues	0	0	0	96,222
Other | Reportable Segment
Revenues:
Total revenues	$ 40,947	$ 37,168	$ 68,297	$ 97,056