Related Party Transactions - Revenues for Services Provided (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Related Party Transaction [Line Items]
Investment advisory and services fees	$ 1,973,837	$ 1,958,250	$ 1,849,105
Distribution revenues	427,156	444,970	465,424
Other revenues	101,169	108,788	105,058
Bernstein research services	493,463	482,538	445,083
Mutual Funds [Member]
Related Party Transaction [Line Items]
Investment advisory and services fees	1,056,227	1,061,677	1,009,901
Distribution revenues	415,380	433,063	455,327
Shareholder servicing fees	85,207	91,020	90,718
Other revenues	4,939	6,694	5,682
Bernstein research services	$ 4	$ 13	$ 113