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		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Fully diluted earnings per share:
Net income (loss) available to common stockholders	$ 14,280	$ 6,429	$ (1,973)	$ (3,921)
Allocations of net income to limited partnership interests in Newmark Holdings, net of tax	6,302	2,421	0	0
Net income (loss) for fully diluted shares	$ 20,582	$ 8,850	$ (1,973)	$ (3,921)
Weighted-average shares:
Common stock outstanding (in shares)	173,469	173,939	174,121	173,254
Partnership units (in shares)	77,955	69,633	0	0
RSUs (Treasury stock method) (in shares)	3,789	879	0	0
Newmark exchange shares (in shares)	391	503	0	0
Fully diluted weighted-average shares of common stock outstanding (in shares)	255,604	244,954	174,121	173,254
Fully diluted earnings per share (in dollars per share)	$ 0.08	$ 0.04	$ (0.01)	$ (0.02)