Condensed Statements of Income - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Income Statement [Abstract]
Equity in net income attributable to AB Unitholders	$ 88,907	$ 69,914
Income taxes	7,820	7,655
Net income	$ 81,087	$ 62,259
Net income per unit:
Basic (in dollars per unit)	$ 0.81	$ 0.63
Diluted (in dollars per unit)	$ 0.81	$ 0.63