Net Income per Unit (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Schedule of net (loss) income per unit [Abstract]
Net income - basic	$ 40,276	$ 21,339	$ 78,507	$ 48,038
Additional allocation of equity in net income attributable to AllianceBernstein resulting from assumed dilutive effect of compensatory options	341	0	592	0
Net income - diluted	$ 40,617	$ 21,339	$ 79,099	$ 48,038
Weighted average units outstanding - basic (in units)	100,888,000	101,424,000	100,595,000	101,595,000
Dilutive effect of compensatory options (in units)	1,251,000	0	1,111,000	0
Weighted average units outstanding - diluted (in units)	102,139,000	101,424,000	101,706,000	101,595,000
Basic net income per unit (in dollars per unit)	$ 0.40	$ 0.21	$ 0.78	$ 0.47
Diluted net income per unit (in dollars per unit)	$ 0.40	$ 0.21	$ 0.78	$ 0.47
Out-of-the-money options excluded from the diluted net income per unit (in units)	2,979,935	9,036,845	2,979,935	9,036,845
Proportional share of the Holding Units held by AllianceBernstein in its consolidated rabbi trust (in hundredths)	37.60%	37.50%	37.60%	37.50%