Condensed Consolidated Statements of Comprehensive Income (unaudited) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Condensed Consolidated Statements of Comprehensive Income (unaudited) [Abstract]
Net income	$ 113,031	$ 94,542
Other comprehensive income (loss):
Foreign currency translation adjustments	(10,320)	1,875
Income tax (expense)	0	0
Foreign currency translation adjustments, net of tax	(10,320)	1,875
Unrealized gains on investments:
Unrealized gains arising during period	742	705
Less: reclassification adjustment for gains included in net income	0	0
Change in unrealized gains on investments	742	705
Income tax (expense)	(383)	(436)
Unrealized gains on investments, net of tax	359	269
Changes in employee benefit related items:
Amortization of transition asset	(36)	(36)
Amortization of prior service cost	27	27
Recognized actuarial loss (gain)	295	(73)
Changes in employee benefit related items	286	(82)
Income tax (expense)	(96)	0
Employee benefit related items, net of tax	190	(82)
Other comprehensive (loss) income	(9,771)	2,062
Less: Comprehensive (loss) income in consolidated entities attributable to non-controlling interests	(1,475)	7,316
Comprehensive income attributable to AllianceBernstein Unitholders	$ 104,735	$ 89,288