Related Party Transactions - Cantor Rights to Purchase Cantor Units from Newmark Holdings (Details)	Jun. 30, 2023 USD ($) shares	Apr. 16, 2023 USD ($) shares	Sep. 30, 2024 shares	Sep. 23, 2024	Nov. 06, 2018	Dec. 13, 2017
Related Party Transaction
Limited partnership units exchange ratio			0.4545	0.9248
Related Party
Related Party Transaction
General partners' capital account, units outstanding (in shares)			662,703
Founding partner interest | Related Party
Related Party Transaction
Issuance of Class A common stock for Newmark RSUs (in shares)	74,026	309,631
Proceeds from the sale of limited partnership interests | $	$ 310,976	$ 1,282,265
Limited partner interest | Related Party
Related Party Transaction
Issuance of Class A common stock for Newmark RSUs (in shares)		38,989
Proceeds from the sale of limited partnership interests | $		$ 166,364
Common Stock
Related Party Transaction
Limited partnership units exchange ratio					1
Class A Common Stock
Related Party Transaction
Limited partnership units exchange ratio						1
Class A Common Stock | Newmark Holdings Units
Related Party Transaction
Limited partnership units exchange ratio			0.9257