Net Income per Unit (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Earnings Per Unit [Abstract]
Net income – basic	$ 56,991	$ 56,316	$ 184,986	$ 210,385
Additional allocation of equity in net income attributable to AB resulting from assumed dilutive effect of compensatory options	0	0	0	2
Net income – diluted	$ 56,991	$ 56,316	$ 184,986	$ 210,387
Weighted average units outstanding – basic (in shares)	113,185,000	100,466,000	113,407,000	99,494,000
Dilutive effect of compensatory options (in shares)	0	0	0	2,000
Weighted average units outstanding – diluted (in shares)	113,185,000	100,466,000	113,407,000	99,496,000
Basic net income per unit (in dollars per share)	$ 0.50	$ 0.56	$ 1.63	$ 2.11
Diluted net income per unit (in dollars per share)	$ 0.50	$ 0.56	$ 1.63	$ 2.11
Anti-dilutive units excluded from diluted net income (in shares)	0	0	0	0