Investment in AB (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Change in Equity Method Investment
Beginning balance	$ 2,074,626	$ 1,623,764
Equity in net income attributable to AB Unitholders	299,781	305,504	$ 416,326
Changes in accumulated other comprehensive income	8,964	(18,303)	1,193
Cash distributions received from AB	(329,900)	(394,470)	(385,236)
Additional investments with proceeds from exercises of compensatory options to buy AB Holding Units	0	178	3,402
Capital contribution to AB	0	1,590	0
Capital contributions from AB	(2,164)	0	(2,346)
AB Holding Units retired	(85,300)	(114,794)	(143,460)
AB Holding Units issued to fund long-term incentive compensation plans	104,167	76,230	151,082
AB Holding Units issued to fund CarVal acquisition	0	589,169
Change in AB Holding Units held by AB for long-term incentive compensation plans	7,366	5,758
Ending balance	$ 2,077,540	$ 2,074,626	$ 1,623,764