CONDENSED CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY - USD ($) $ in Thousands	Total	Common Stock Class A Common Stock	Common Stock Class B Common Stock	Common Stock Contingent Class A Common Stock	Additional Paid-in Capital	Treasury Stock	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Noncontrolling Interests
Balance at beginning of period at Dec. 31, 2021	$ 1,664,193	$ 1,940	$ 212	$ 1,572	$ 487,447	$ (290,174)	$ 1,079,661	$ (2,731)	$ 386,266
Increase (Decrease) in Stockholders' Equity
Consolidated net income	100,420						76,848		23,572
Foreign currency translation adjustments	(16,474)							(13,178)	(3,296)
Cantor purchase of Cantor units from Newmark Holdings upon redemption/exchange of FPU's	863								863
Dividends to common stockholders	(12,753)						(12,753)
Earnings distributions to limited partnership interests and other noncontrolling interests	(54,024)								(54,024)
Grant of exchangeability, redemption and issuance of Class A common stock	72,238	55			57,022				15,161
Contributions of capital to and from Cantor for equity-based compensation	505				407				98
Repurchase of Class A common stock	(281,193)					(237,206)			(43,987)
Restricted stock units compensation	10,339				8,688				1,651
Balance at end of period at Sep. 30, 2022	1,484,114	1,995	212	1,572	553,564	(527,380)	1,143,756	(15,909)	326,304
Balance at beginning of period at Jun. 30, 2022	1,521,002	1,988	212	1,572	523,504	(440,444)	1,121,150	(9,116)	322,136
Increase (Decrease) in Stockholders' Equity
Consolidated net income	37,910						27,964		9,946
Foreign currency translation adjustments	(8,883)							(6,793)	(2,090)
Cantor purchase of Cantor units from Newmark Holdings upon redemption/exchange of FPU's	0								0
Dividends to common stockholders	(5,358)						(5,358)
Earnings distributions to limited partnership interests and other noncontrolling interests	5,882								5,882
Grant of exchangeability, redemption and issuance of Class A common stock	33,937	7			26,028				7,902
Contributions of capital to and from Cantor for equity-based compensation	(819)				(682)				(137)
Repurchase of Class A common stock	(105,265)					(86,936)			(18,329)
Restricted stock units compensation	5,708				4,714				994
Balance at end of period at Sep. 30, 2022	1,484,114	1,995	212	1,572	553,564	(527,380)	1,143,756	(15,909)	326,304
Balance at beginning of period at Dec. 31, 2022	1,524,865	2,011	212	0	584,709	(538,612)	1,145,006	(11,989)	343,528
Increase (Decrease) in Stockholders' Equity
Consolidated net income	9,034						6,027		3,007
Foreign currency translation adjustments	(1,895)							(1,460)	(435)
Cantor purchase of Cantor units from Newmark Holdings upon redemption/exchange of FPU's	1,760								1,760
Dividends to common stockholders	(15,686)						(15,686)
Purchase of noncontrolling interests	(21,946)				(3,462)				(18,484)
Earnings distributions to limited partnership interests and other noncontrolling interests	(32,179)								(32,179)
Grant of exchangeability, redemption and issuance of Class A common stock	54,196	62			39,554				14,580
Contributions of capital to and from Cantor for equity-based compensation	(2,437)				(1,902)				(535)
Repurchase of Class A common stock	(32,270)					(26,434)			(5,836)
Restricted stock units compensation	15,054				12,386				2,668
Balance at end of period at Sep. 30, 2023	1,498,496	2,073	212	0	631,285	(565,046)	1,135,347	(13,449)	308,074
Balance at beginning of period at Jun. 30, 2023	1,495,211	2,053	212	0	613,847	(549,617)	1,130,645	(5,443)	303,514
Increase (Decrease) in Stockholders' Equity
Consolidated net income	14,153						9,947		4,206
Foreign currency translation adjustments	(9,846)							(8,006)	(1,840)
Dividends to common stockholders	(5,245)						(5,245)
Earnings distributions to limited partnership interests and other noncontrolling interests	(440)								(440)
Grant of exchangeability, redemption and issuance of Class A common stock	19,990	20			14,385				5,585
Contributions of capital to and from Cantor for equity-based compensation	(1,931)				(1,445)				(486)
Repurchase of Class A common stock	(18,909)					(15,429)			(3,480)
Restricted stock units compensation	5,513				4,498				1,015
Balance at end of period at Sep. 30, 2023	$ 1,498,496	$ 2,073	$ 212	$ 0	$ 631,285	$ (565,046)	$ 1,135,347	$ (13,449)	$ 308,074