Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Statement of Comprehensive Income [Abstract]
Net income	$ 173,731	$ 130,237	$ 463,611	$ 425,412
Other comprehensive income (loss):
Foreign currency translation adjustment, before reclassification and tax	437	(7,161)	539	(11,838)
Less: reclassification adjustment for (losses) gains included in net income upon liquidation	(6)	0	(6)	1,542
Foreign currency translation adjustments, before tax	443	(7,161)	545	(13,380)
Income tax expense	0	0	0	0
Foreign currency translation adjustments, net of tax	443	(7,161)	545	(13,380)
Unrealized gains (losses) on investments:
Unrealized gains (losses) arising during period	12	(11)	(7)	(352)
Less: reclassification adjustment for (losses) gains included in net income	(7)	1,270	(10)	1,270
Change in unrealized gains (losses) on investments	19	(1,281)	3	(1,622)
Income tax (expense) benefit	(8)	420	(5)	700
Unrealized gains (losses) on investments, net of tax	11	(861)	(2)	(922)
Changes in employee benefit related items:
Amortization of prior service cost	6	0	87	0
Recognized actuarial gain	244	251	202	726
Changes in employee benefit related items	250	251	289	726
Income tax benefit (expense)	24	(22)	(51)	(87)
Employee benefit related items, net of tax	274	229	238	639
Other comprehensive income (loss)	728	(7,793)	781	(13,663)
Less: Comprehensive income (loss) in consolidated entities attributable to non-controlling interests	15,725	(3,109)	14,815	4,782
Comprehensive income attributable to AB Unitholders	$ 158,734	$ 125,553	$ 449,577	$ 406,967