Statements of Income - USD ($) $ in Thousands	3 Months Ended																12 Months Ended
	Dec. 31, 2015		Sep. 30, 2015		Jun. 30, 2015		Mar. 31, 2015		Dec. 31, 2014		Sep. 30, 2014		Jun. 30, 2014		Mar. 31, 2014		Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Statement [Abstract]
Equity in net income attributable to AB Unitholders	$ 57,485		$ 48,988		$ 54,409		$ 51,616		$ 63,563		$ 49,876		$ 48,467		$ 41,371		$ 212,498	$ 203,277	$ 185,912
Income taxes																	24,320	22,463	20,410
Net income	$ 51,682		$ 42,687		$ 48,224		$ 45,585		$ 57,667		$ 44,134		$ 42,854		$ 36,159		$ 188,178	$ 180,814	$ 165,502
Net income per unit:
Basic (in dollars per share)	$ 0.53	[1]	$ 0.43	[1]	$ 0.48	[1]	$ 0.45	[1]	$ 0.59	[1]	$ 0.45	[1]	$ 0.44	[1]	$ 0.38	[1]	$ 1.89	$ 1.87	$ 1.72
Diluted (in dollars per share)	$ 0.53	[1]	$ 0.43	[1]	$ 0.48	[1]	$ 0.45	[1]	$ 0.59	[1]	$ 0.45	[1]	$ 0.44	[1]	$ 0.38	[1]	$ 1.89	$ 1.86	$ 1.71

[1] Basic and diluted net income per unit are computed independently for each of the periods presented. Accordingly, the sum of the quarterly net income per unit amounts may not agree to the total for the year.