Earnings Per Share and Weighted-Average Shares Outstanding - Schedule of Fully Diluted Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Fully diluted earnings per share:
Net income (loss) available to common stockholders	$ 17,794	$ 9,947	$ 15,820	$ 6,027
Allocations of net income to limited partnership interests in Newmark Holdings, net of tax	8,357	4,128	7,148	2,266
Net income (loss) for fully diluted shares	$ 26,151	$ 14,075	$ 22,968	$ 8,293
Weighted-average shares:
Common stock outstanding (in shares)	170,088	174,129	172,767	173,549
Partnership units (in shares)	79,371	71,125	77,792	68,658
RSUs (Treasury stock method) (in shares)	5,138	1,463	4,398	1,193
Newmark exchange shares (in shares)	373	523	419	482
Fully diluted weighted-average shares of common stock outstanding (in shares)	254,970	247,240	255,376	243,882
Fully diluted earnings per share (in dollars per share)	$ 0.10	$ 0.06	$ 0.09	$ 0.03