Condensed Statements of Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Income Statement [Abstract]
Equity in net income attributable to AB Unitholders	$ 72,802	$ 49,055	$ 203,888	$ 146,668
Income taxes	6,902	5,877	21,371	17,839
Net income	$ 65,900	$ 43,178	$ 182,517	$ 128,829
Net income per unit:
Basic (in dollars per unit)	$ 0.68	$ 0.46	$ 1.87	$ 1.35
Diluted (in dollars per unit)	$ 0.68	$ 0.46	$ 1.87	$ 1.35