Condensed Statements of Income - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Income Statement [Abstract]
Equity in net income attributable to AB Unitholders	$ 65,698	$ 49,666
Income taxes	7,538	5,756
Net income	$ 58,160	$ 43,910
Net income per unit:
Basic (in dollars per unit)	$ 0.60	$ 0.46
Diluted (in dollars per unit)	$ 0.60	$ 0.46