Net Income Per Unit (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended																12 Months Ended
	Dec. 31, 2019		Sep. 30, 2019		Jun. 30, 2019		Mar. 31, 2019		Dec. 31, 2018		Sep. 30, 2018		Jun. 30, 2018		Mar. 31, 2018		Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Earnings Per Share [Abstract]
Percentage of General Partnership interest in company																	1.00%
Percentage of Limited Partners interest in Company																	99.00%
Net income per unit, basic and diluted [Abstract]
Net income attributable to AB Unitholders	$ 248,865		$ 187,811		$ 166,252		$ 149,114		$ 188,053		$ 203,674		$ 181,665		$ 184,196		$ 752,042	$ 757,588	$ 662,403
Weighted average units outstanding—basic (in units)																	268,075,000	269,236,000	266,955,000
Dilutive effect of compensatory options to buy AB Holding Units (in units)																	44,000	251,000	430,000
Weighted average units outstanding - diluted (in units)																	268,119,000	269,487,000	267,385,000
Basic net income per AB Unit (in dollars per unit)	$ 0.92	[1]	$ 0.69	[1]	$ 0.61	[1]	$ 0.55	[1]	$ 0.70	[1]	$ 0.75	[1]	$ 0.66	[1]	$ 0.68	[1]	$ 2.78	$ 2.79	$ 2.46
Diluted net income per AB Unit (in dollars per unit)	$ 0.92	[1]	$ 0.69	[1]	$ 0.61	[1]	$ 0.55	[1]	$ 0.70	[1]	$ 0.75	[1]	$ 0.66	[1]	$ 0.68	[1]	$ 2.78	$ 2.78	$ 2.45
Options excluded from diluted net income per unit computation due to their anti-dilutive effect (in units)																	29,056	49,784	1,970,741

[1] Basic and diluted net income per unit are computed independently for each of the periods presented. Accordingly, the sum of the quarterly net income per unit amounts may not agree to the total for the year.