Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Statement of Comprehensive Income [Abstract]
Net income	$ 156,255	$ 160,536
Other comprehensive income (loss):
Foreign currency translation adjustments, before tax	9,001	5,225
Income tax expense	(134)	0
Foreign currency translation adjustments, net of tax	8,867	5,225
Unrealized gains (losses) on investments:
Unrealized (losses) arising during period	(16)	(8)
Less: reclassification adjustment for (losses) included in net income	0	(3)
Change in unrealized gains (losses) on investments	(16)	(5)
Income tax expense	(2)	(1)
Unrealized (losses) on investments, net of tax	(18)	(6)
Changes in employee benefit related items:
Amortization of prior service cost	6	71
Recognized actuarial loss (gain)	259	(433)
Changes in employee benefit related items	265	(362)
Income tax expense	(76)	(71)
Employee benefit related items, net of tax	189	(433)
Other comprehensive income	9,038	4,786
Less: Comprehensive income (loss) in consolidated entities attributable to non-controlling interests	16,394	(5,697)
Comprehensive income attributable to AB Unitholders	$ 148,899	$ 171,019