Condensed Statements of Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Income Statement [Abstract]
Equity in net income attributable to AB Unitholders	$ 73,874	$ 66,722	$ 206,989	$ 178,383
Income taxes	6,875	6,894	20,805	19,842
Net income	$ 66,999	$ 59,828	$ 186,184	$ 158,541
Net income per unit:
Basic (in dollars per unit)	$ 0.70	$ 0.62	$ 1.95	$ 1.65
Diluted (in dollars per unit)	$ 0.70	$ 0.62	$ 1.95	$ 1.65