Investment in AB (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Change in Equity Method Investment [Roll Forward]
Beginning balance			$ 2,074,626
Equity in net income attributable to AB Unitholders	$ 65,761	$ 63,905	211,264	$ 233,616
Changes in accumulated other comprehensive income	(5,643)	$ (11,495)	(1,122)	(27,094)
Cash distributions received from AB			(248,529)	$ (313,438)
Capital contributions (from) AB			(2,499)
AB Holding Units retired			(72,592)
AB Holding Units issued to fund long-term incentive compensation plans			8,005
Change in AB Holding Units held by AB for long-term incentive compensation plans			3,893
Ending balance	$ 1,973,046		$ 1,973,046