Net Income Per Unit (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Net Income Per Unit [Abstract]
General Partnership Interest In Company (in hundredths)	1.00%
Limited Partners interest in Company (in hundredths)	99.00%
Net income per unit, basic and diluted [Abstract]
Net income attributable to AllianceBernstein Unitholders	$ 114,516	$ 87,278
Weighted average units outstanding - basic (in units)	277,786	277,846
Dilutive effect of compensatory options to buy Holding Units (in units)	937	0
Weighted average units outstanding - diluted (in units)	278,723	277,846
Basic net income (loss) per AllianceBernstein Unit (in dollars per unit)	$ 0.41	$ 0.31
Diluted net income (loss) per AllianceBernstein Unit (in dollars per unit)	$ 0.41	$ 0.31
Options excluded from diluted net income per unit computation due to their anti-dilutive effect (in units)	3,161,304	8,977,349