Condensed Consolidated Statements of Comprehensive Income (unaudited) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Condensed Consolidated Statements of Comprehensive Income (unaudited) [Abstract]
Net (loss) income	$ (48,249)	$ 72,536	$ 119,202	$ 308,345
Other comprehensive income (loss), before taxes:
Foreign currency translation adjustment	6,197	(11,790)	4,186	1,514
Unrealized gains on investments:
Unrealized gains (loss) arising during period	321	(921)	1,091	(333)
Less: reclassification adjustment for gains (losses) included in net income	(45)	40	(27)	(88)
Change in unrealized gains (losses) on investments	366	(961)	1,118	(245)
Changes in employee benefit related items:
Amortization of transition asset	(35)	(35)	(107)	(107)
Amortization of prior service cost	26	27	80	80
Recognized actuarial loss (gain)	211	(34)	365	50
Other comprehensive (loss) income, before taxes	6,765	(12,793)	5,642	1,292
Income tax expense	(390)	(415)	(59)	(1,104)
Other comprehensive income (loss), after taxes	6,375	(13,208)	5,583	188
Less: Comprehensive income (loss) in consolidated entities attributable to non-controlling interests	(3,933)	(18,571)	1,994	(33,660)
Comprehensive (loss) income attributable to AllianceBernstein Unitholders	$ (37,941)	$ 77,899	$ 122,791	$ 342,193