Condensed Statements of Income (unaudited) (USD $)
In Thousands, except Per Share data, unless otherwise specified
3 Months Ended
Mar. 31, 2015
Mar. 31, 2014
Condensed Statements of Income (unaudited) [Abstract]    
Equity in net income attributable to AB Unitholders $ 51,616 $ 41,371
Income taxes 6,031 5,212
Net income $ 45,585 $ 36,159
Net income per unit:    
Basic (in dollars per share) $ 0.45 $ 0.38
Diluted (in dollars per share) $ 0.45 $ 0.38