Revenue Recognition (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Disaggregation of Revenue [Line Items]
Revenue subject to contracts with customers	$ 4,405,040	$ 3,688,518	$ 3,430,316
Dividend and interest income, net of interest expense	35,048	35,273	47,216
Investment (losses) gains	(636)	(16,401)	38,659
Other revenues	2,150	1,146	2,241
Revenue not subject to contract with customer	36,562	20,018	88,116
Net revenues	4,441,602	3,708,536	3,518,432
Base fees
Disaggregation of Revenue [Line Items]
Revenue subject to contracts with customers	2,949,405	2,462,810	2,372,429
Performance-based fees
Disaggregation of Revenue [Line Items]
Revenue subject to contracts with customers	245,119	132,626	99,615
Bernstein research services
Disaggregation of Revenue [Line Items]
Revenue subject to contracts with customers	452,017	459,744	407,911
All-in-management fees
Disaggregation of Revenue [Line Items]
Revenue subject to contracts with customers	350,674	331,268	291,999
12b-1 fees
Disaggregation of Revenue [Line Items]
Revenue subject to contracts with customers	83,920	75,973	80,268
Other distribution fees
Disaggregation of Revenue [Line Items]
Revenue subject to contracts with customers	217,646	122,540	82,776
Shareholder servicing fees
Disaggregation of Revenue [Line Items]
Revenue subject to contracts with customers	90,225	82,317	77,394
Other
Disaggregation of Revenue [Line Items]
Revenue subject to contracts with customers	$ 16,034	$ 21,240	$ 17,924