Revenue Recognition (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Disaggregation of Revenue [Line Items]
Revenue subject to contracts with customers	$ 4,048,736	$ 4,099,287	$ 4,405,040
Dividend and interest income, net of interest expense	91,902	56,653	35,048
Investment gains (losses)	14,206	(102,413)	(636)
Other revenues	479	763	2,150
Revenue not subject to contract with customer	106,587	(44,997)	36,562
Net revenues	4,155,323	4,054,290	4,441,602
Base fees
Disaggregation of Revenue [Line Items]
Revenue subject to contracts with customers	2,830,557	2,825,791	2,949,405
Performance-based fees
Disaggregation of Revenue [Line Items]
Revenue subject to contracts with customers	144,911	145,247	245,119
Bernstein research services
Disaggregation of Revenue [Line Items]
Revenue subject to contracts with customers	386,142	416,273	452,017
All-in-management fees
Disaggregation of Revenue [Line Items]
Revenue subject to contracts with customers	284,057	290,740	350,674
12b-1 fees
Disaggregation of Revenue [Line Items]
Revenue subject to contracts with customers	63,127	69,041	83,920
Other distribution fees
Disaggregation of Revenue [Line Items]
Revenue subject to contracts with customers	239,079	247,414	217,646
Shareholder servicing fees
Disaggregation of Revenue [Line Items]
Revenue subject to contracts with customers	83,802	86,661	90,225
Other
Disaggregation of Revenue [Line Items]
Revenue subject to contracts with customers	$ 17,061	$ 18,120	$ 16,034