Condensed Statements of Income - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Income Statement [Abstract]
Equity in net income attributable to AB Unitholders	$ 52,638	$ 65,698
Income taxes	6,199	7,538
Net income	$ 46,439	$ 58,160
Net income per unit:
Basic (in dollars per unit)	$ 0.49	$ 0.60
Diluted (in dollars per unit)	$ 0.49	$ 0.60