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, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Fully diluted earnings per share:
Net income (loss) available to common stockholders	$ 20,819	$ 14,280	$ 12,053	$ (1,973)
Allocations of net income to limited partnership interests in Newmark Holdings, net of tax	7,954	6,302	4,048	0
Net income (loss) for fully diluted shares	$ 28,773	$ 20,582	$ 16,101	$ (1,973)
Weighted-average shares:
Common stock outstanding (in shares)	179,560	173,469	177,965	174,121
Partnership units (in shares)	69,512	77,955	71,684	0
RSUs (Treasury stock method) (in shares)	3,260	3,789	3,724	0
Newmark exchange shares (in shares)	282	391	297	0
Fully diluted weighted-average shares of common stock outstanding (in shares)	252,614	255,604	253,670	174,121
Fully diluted earnings per share (in dollars per share)	$ 0.11	$ 0.08	$ 0.06	$ (0.01)