CONDENSED CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY (Parenthetical) - $ / shares	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Dividends declared per share of common stock (in dollars per share)	$ 0.03	$ 0.03	$ 0.09	$ 0.09
Dividends declared and paid per share of common stock (in dollars per share)	$ 0.03	$ 0.03	$ 0.09	$ 0.07
FPU's
Cantor purchase of Cantor units from Newmark Holdings upon redemption/exchange of FPU's (in shares)			422,646
Cantor | FPU's | Related Party
Cantor purchase of Cantor units from Newmark Holdings upon redemption/exchange of FPU's (in shares)				208,276
Class A Common Stock
Cantor purchase of Cantor units from Newmark Holdings upon redemption/exchange of FPU's (in shares)	1,069,447	0	1,069,447	1,767,736
Treasury stock repurchases (in shares)	2,787,291	10,163,677	5,141,508	23,217,195
Class A Common Stock | Common Stock
Grant of exchangeability, redemption and issuance of limited partnership interests and issuance of common stock (in shares)	2,014,382	691,844	6,218,592	5,502,373
Treasury stock repurchases (in shares)	2,787,291	10,163,677	5,141,508	23,217,195