Revenue Recognition (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Disaggregation of Revenue [Line Items]
Revenue subject to contracts with customers	$ 4,406,318	$ 4,048,736	$ 4,099,287
Dividend and interest income, net of interest expense	80,800	91,902	56,653
Investment (losses) gains	(13,486)	14,206	(102,413)
Other revenues	1,507	479	763
Revenue not subject to contract with customer	68,821	106,587	(44,997)
Net revenues	4,475,139	4,155,323	4,054,290
Base fees
Disaggregation of Revenue [Line Items]
Revenue subject to contracts with customers	3,171,175	2,830,557	2,825,791
Performance-based fees
Disaggregation of Revenue [Line Items]
Revenue subject to contracts with customers	270,964	144,911	145,247
Bernstein research services
Disaggregation of Revenue [Line Items]
Revenue subject to contracts with customers	96,222	386,142	416,273
All-in-management fees
Disaggregation of Revenue [Line Items]
Revenue subject to contracts with customers	337,999	284,057	290,740
12b-1 fees
Disaggregation of Revenue [Line Items]
Revenue subject to contracts with customers	67,611	63,127	69,041
Other distribution fees
Disaggregation of Revenue [Line Items]
Revenue subject to contracts with customers	321,060	239,079	247,414
Shareholder servicing fees
Disaggregation of Revenue [Line Items]
Revenue subject to contracts with customers	89,195	83,802	86,661
JV related revenues
Disaggregation of Revenue [Line Items]
Revenue subject to contracts with customers	37,775	0	0
Other
Disaggregation of Revenue [Line Items]
Revenue subject to contracts with customers	$ 14,317	$ 17,061	$ 18,120