Net Income per Unit (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
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	$ 184,196	$ 139,937
Weighted average limited partnership units outstanding – basic (in units)	269,184,000	268,479,000
Dilutive effect of compensatory options to buy AB Holding Units (in units)	336,000	534,000
Weighted average limited partnership units outstanding – diluted (in units)	269,520,000	269,013,000
Basic net income per AB Unit (in dollars per unit)	$ 0.68	$ 0.52
Diluted net income per AB Unit (in dollars per unit)	$ 0.68	$ 0.51
Options excluded from diluted net income per unit computation due to their anti-dilutive effect (in units)	1,225,731	2,437,307