Net Income per Unit (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Schedule of net (loss) income per unit [Abstract]
Net income - basic	$ 42,854	$ 40,276	$ 79,013	$ 78,507
Additional allocation of equity in net income attributable to AllianceBernstein resulting from assumed dilutive effect of compensatory options	376	341	672	592
Net income - diluted	$ 43,230	$ 40,617	$ 79,685	$ 79,099
Weighted average units outstanding - basic (in units)	96,451,000	100,888,000	96,284,000	100,595,000
Dilutive effect of compensatory options (in units)	1,169,000	1,251,000	1,127,000	1,111,000
Weighted average units outstanding - diluted (in units)	97,620,000	102,139,000	97,411,000	101,706,000
Basic net income per unit (in dollars per unit)	$ 0.44	$ 0.40	$ 0.82	$ 0.78
Diluted net income per unit (in dollars per unit)	$ 0.44	$ 0.40	$ 0.82	$ 0.78
Out-of-the-money options excluded from the diluted net income per unit (in units)	2,806,033	2,979,935	2,806,033	2,979,935
Schedule of Equity Method Investments [Line Items]
Proportional share of the Holding Units held in consolidated rabbi trust (in hundredths)	35.50%	37.60%	35.50%	37.60%
Unallocated Holding Units Held in Consolidated Rabbi Trust [Member]
Schedule of Equity Method Investments [Line Items]
Proportional share of the Holding Units held in consolidated rabbi trust (in hundredths)		37.60%		37.60%