Condensed Statements of Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Income Statement [Abstract]
Equity in net income attributable to AB Unitholders	$ 66,722	$ 72,802	$ 178,383	$ 203,888
Income taxes	6,894	6,902	19,842	21,371
Net income	$ 59,828	$ 65,900	$ 158,541	$ 182,517
Net income per unit:
Basic (in dollars per unit)	$ 0.62	$ 0.68	$ 1.65	$ 1.87
Diluted (in dollars per unit)	$ 0.62	$ 0.68	$ 1.65	$ 1.87