Income Taxes (Tables)

6 Months Ended

Jun. 30, 2018

Income Tax Disclosure [Abstract]

Computation of Effective Income Tax Rate and Changes in Components of Income Tax

	Three Months Ended June 30,								Six Months Ended June 30,
	2018			2017			% Change		2018			2017			% Change
	(in thousands)
Net income attributable to AB Unitholders	$	181,665		$	135,103		34.5	%	$	365,861		$	275,040		33.0	%
Multiplied by: weighted average equity ownership interest	36.0		%	35.5		%			35.8		%	35.5		%
Equity in net income attributable to AB Unitholders	$	65,388		$	47,947		36.4		$	131,086		$	97,613		34.3
AB qualifying revenues	$	643,009		$	586,478		9.6		$	1,345,927		$	1,132,655		18.8
Multiplied by: weighted average equity ownership interest for calculating tax	30.2		%	29.7		%			30.2		%	29.6		%
Multiplied by: federal tax	3.5		%	3.5		%			3.5		%	3.5		%
Federal income taxes	6,794			6,099					14,204			11,750
State income taxes	137			107					265			212
Total income taxes	$	6,931		$	6,206		11.7		$	14,469		$	11,962		21.0
Effective tax rate	10.6		%	12.9		%			11.0		%	12.3		%