Net Income per Unit (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Earnings Per Unit [Abstract]
General partnership interest in Company (percent)	1.00%
Limited Partners interest in Company (as a percent)	99.00%
Net income per unit, basic and diluted [Abstract]
Net income attributable to AB Unitholders	$ 149,114	$ 184,196
Weighted average limited partnership units outstanding – basic (in units)	267,336,000	269,184,000
Dilutive effect of compensatory options to buy AB Holding Units (in units)	72,000	336,000
Weighted average limited partnership units outstanding – diluted (in units)	267,408,000	269,520,000
Basic net income per AB Unit (in dollars per unit)	$ 0.55	$ 0.68
Diluted net income per AB Unit (in dollars per unit)	$ 0.55	$ 0.68
Options excluded from diluted net income per unit computation due to their anti-dilutive effect (in units)	29,056	1,225,731