Net Income per Unit (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Limited Partners interest in Company (as a percent)			99.00%
Net income per unit, basic and diluted [Abstract]
Net income attributable to AB Unitholders	$ 177,321	$ 166,252	$ 371,641	$ 315,366
Weighted average limited partnership units outstanding – basic (in units)	269,081,000	268,475,000	269,789,000	267,909,000
Dilutive effect of compensatory options to buy AB Holding Units (in units)	9,000	48,000	22,000	60,000
Weighted average limited partnership units outstanding – diluted (in units)	269,090,000	268,523,000	269,811,000	267,969,000
Basic net income per AB Unit (in dollars per unit)	$ 0.65	$ 0.61	$ 1.36	$ 1.17
Diluted net income per AB Unit (in dollars per unit)	$ 0.65	$ 0.61	$ 1.36	$ 1.17
Options excluded from diluted net income per unit computation due to their anti-dilutive effect (in units)	44,877	29,056	44,877	29,056
General Partner Interest
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
General partnership interest in Company (percent)			1.00%