Business Description Organization and Basis of Presentation (Revision) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Income taxes	$ 10,265	$ 13,231	$ 20,322	$ 25,737
Net income attributable to AB Unitholders	$ 135,103	$ 124,501	$ 275,040	$ 290,785
Basic net income per AB Unit (in dollars per unit)	$ 0.50	$ 0.46	$ 1.01	$ 1.06
Diluted net income per AB Unit (in dollars per unit)	$ 0.50	$ 0.46	$ 1.01	$ 1.06
As Reported
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Income taxes		$ 10,588		$ 20,452
Net income attributable to AB Unitholders		$ 127,144		$ 296,070
Basic net income per AB Unit (in dollars per unit)		$ 0.47		$ 1.08
Diluted net income per AB Unit (in dollars per unit)		$ 0.47		$ 1.08
Adjustment
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Income taxes		$ 2,643		$ 5,285
Net income attributable to AB Unitholders		$ (2,643)		$ (5,285)
Basic net income per AB Unit (in dollars per unit)		$ (0.01)		$ (0.02)
Diluted net income per AB Unit (in dollars per unit)		$ (0.01)		$ (0.02)