Net Income Per Unit (Details) (USD $) In Thousands, except Share data	3 Months Ended		9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Earnings Per Unit [Abstract]
Net income - basic	$ 27,003	$ 12,215	$ 106,195	$ 91,233
Additional allocation of equity in net income attributable to AllianceBernstein resulting from assumed dilutive effect of compensatory options	0	169	240	1,228
Net income - diluted	$ 27,003	$ 12,384	$ 106,435	$ 92,461
Weighted average units outstanding - basic (in units)	103,156	100,893	103,915	101,236
Dilutive effect of compensatory options (in units)	0	1,444	316	1,776
Weighted average units outstanding - diluted (in units)	103,156	102,337	104,231	103,012
Basic net income per unit (in dollars per unit)	$ 0.26	$ 0.12	$ 1.02	$ 0.90
Diluted net income per unit (in dollars per unit)	$ 0.26	$ 0.12	$ 1.02	$ 0.90
Out-of-the-money options from the diluted net income per unit (in units)	9,590,691	5,279,772	4,307,713	4,918,021